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  china-xuba.com
Geschrieben von: bop17mo - 25.04.2022, 02:35 - Forum: Allgemein - Keine Antworten

The Courses for Early Language Education reflects Xuba Language Enlightenment's value orientation in the process of children's learning of their mother tongue, and it is one aspect of Xuba Language Enlightenment's multi-dimensional value concept. Therefore, the courses for early language education is not a teaching method in a simple sense, nor is it a teaching material for children to learn their mother tongue in the conventional concept. On the contrary, the courses has the universal characteristics of general pedagogy, and then has its own independent system. Therefore, we prefer to regard the language course as a curriculum model for children's diversified learning with language as the carrier.
It is not difficult to find that each part of the courses of language construction involves a wide range of elements that affect the development of educational and teaching activities: the values pursued by educational and teaching activities, the content stipulated in educational and teaching activities, the methods selected for educational and teaching activities, The operation model of education and teaching activities, the basic requirements followed by education and teaching activities, the detection and evaluation system of the quality of education and teaching activities, and the many details that should be paid attention to in the process of education and teaching activities.
The Teaching Products for Early Language Education we provide includes English basic word cards, English advanced word cards, English phonics cards and picture book reading device. English basic word cards also known as XUBA 243 word cards, 243 words are selected which are suitable for English enlightenment. With recto-verso print, the cards are point-reading sensitive and suitable for flashing and point-reading. English advanced word cards, it is composed of 1000 basic words that have been carefully selected, covering the body, home, fruits, vegetables, animals, birds, insects and things of other aspects. Selection follows the principle of commonness, interest and expansion, avoiding the principle of abstract words. English phonics cards contains phoneme cards, joint pronunciation cards, English phonetic cards. The joint pronunciation cards and the English phonetic cards are distinctive cards from Xuba Language, which can help the children to master the joint pronunciation and the English sound parts quickly. Mastering of these cards can lay a good foundation for children's phonics learning. And Teaching Cards for Early Education also happen to cover the three items mentioned above.
Tests for Early Language Education contains two aspects, they are spoken English test young learners and training for spoken English test for young learners. ISET-YL (International Spoken English Test for Young Learners) is developed and supervised by IEERA. Founded in 1965 and headquartered in New York, IEERA is a maker of International Standards for English education, and a guidance provider to English education institutes throughout the world to implement high level English education programs and standards. At present, ISET-YL certificate is accepted in 159 countries or regions. It is recognized and used by over 20 thousand international academies or institutions with 18 million candidates worldwide. This certification enjoys a good reputation of "qualification passport".
Books for Early Language Education consists of Early English Eduaction for Babies, English Words for Children Volume One&Two, Early English Education Instructors Textbook, English Class for Fun 0-3&3-6 Years Old and so on. With native language enlightenment method for babies to increase vocabulary base rapidly and facilitating sound parenting reading habit, these books will help children to easily achieve native English listening ability equivalent to their Chinese level. And also these are a very practical book of words cognition for English enlightenment. Based on Xuba's researches, understandings and practices on children's cognition areas, principles of closing to life, expanding and interest are considered. Words of 31 themes are selected that cover every aspect of children's recognition towards things around them in their early development stages. Main body of these books are all in English to develop children's English thinking. Rich colors and adorable images of the book are helpful for children to accumulate 1000 situational words and phrases easily in their golden stage of recognition.
Peripheral Products for Early Language Education includes little school bag yellow & blue, which can be innovated and has a super capacity, and it is easy to clean for its waterproof properties; and multifunction early education Smart Machine blue & pink, it is only a system, but also an English practice class for children and a personal English AI tutor, who can help children improve their oral English ability before school and in K12, and can perfectly interpret the challenges of K12 oral English test. The content of the system covers 31 versions of K12 textbooks, providing a full set of graded English courses and connecting with the oral English test. And it can also enable the children to do practices in multiple scenes for various oral English tests. By introducing synchronous English textbooks of dozens of publishing houses nationwide, Biba can save your effort and money and acts better than a professional English teacher. It also has the same standard as the National Examination Center. Meanwhile, Biba M15 provides a set of oral cards. For example, for "书本" in English: "BOOK", Biba first reads the standard pronunciation, and then the child listen and repeat. Then Biba can test whether the children's English pronunciation is accurate or not, and makes the whole word pronunciation assessment precisely. If children speak correctly,it will automatically jump onto another word. If you do not speak correctly, Biba will also encourage you to read it again, a test up to three times. The same goes for sentence training. If you still want to listen and repeat, you can press the forward or the backward button, which is super effective for the development of children's language skills.

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  antenkconnector.com
Geschrieben von: bop17mo - 25.04.2022, 02:30 - Forum: Allgemein - Keine Antworten

DIN 41612 was a DIN standard for electrical connectors that are widely used in rack based electrical systems. Standardisation of the connectors is a pre-requisite for open systems, where users expect components from different suppliers to operate together. The most widely known use of DIN 41612 connectors is in the VMEbus and NuBus systems. The standard has withdrawn in favor of international standards IEC 60603-2 and EN 60603-2. DIN 41612 connectors are used in Pancon, STEbus, Futurebus, VMEbus, Multibus II, NuBus, VXI Bus, eurocard TRAM motherboards, and Europe Card Bus, all of which typically use male DIN 41612 connectors on Eurocards plugged into female DIN 41612 on the backplane in a 19-inch rack chassis. The standard describes connectors which may have one, two or three rows of contacts, which are labelled as rows a, b and c. Two row connectors may use rows a+b or rows a+c. The connectors may have 16 or 32 columns, which means that the possible permutations allow 16, 32, 48, 64 or 96 contacts. The rows and columns are on a 0.1 inch (2.54 mm) grid pitch. Insertion and removal force are controlled, and three durability grades are available. Often the female DIN 41612 connectors have press fit contacts rather than solder pin contacts, to avoid thermal shock to the backplane.
battery holder is one or more compartments or chambers for holding a battery. For dry cells, the holder must also make electrical contact with the battery terminals. For wet cells, cables are often connected to the battery terminals, as is found in automobiles or emergency lighting equipment. A battery holder is either a plastic case with the shape of the housing moulded as a compartment or compartments that accepts a battery or batteries, or a separate plastic holder that is mounted with screws, eyelets, glue, double-sided tape, or other means. Battery holders may have a lid to retain and protect the batteries or may be sealed to prevent damage to circuitry and components from battery leakage. Coiled spring wire or flat tabs that press against the battery terminals are the two most common methods of making the electrical connection inside a holder. External connections on battery holders are usually made by contacts with pins, surface mount feet, solder lugs, or wire leads. Where the battery is expected to last over the life of the product, no holder is necessary, and a tab welded to the battery terminals can be directly soldered to a printed circuit board.
pin header (or simply header) is a form of electrical connector. A male pin header consists of one or more rows of metal pins molded into a plastic base, often 2.54 mm (0.1 in) apart, though available in many spacings. Male pin headers are cost-effective due to their simplicity. The female counterparts are sometimes known as female socket headers, though there are numerous naming variations of male and female connectors. Historically, headers have sometimes been called "Berg connectors", but headers are manufactured by many companies.
SCSI connector is used to connect computer parts that use a system called SCSI to communicate with each other. Generally, two connectors, designated male and female, plug together to form a connection which allows two components, such as a computer and a disk drive, to communicate with each other. SCSI connectors can be electrical connectors or optical connectors. There have been a large variety of SCSI connectors in use at one time or another in the computer industry. Twenty-five years of evolution and three major revisions of the standards resulted in requirements for Parallel SCSI connectors that could handle an 8, 16 or 32 bit wide bus running at 5, 10 or 20 megatransfer/s, with conventional or differential signaling. Serial SCSI added another three transport types, each with one or more connector types. Manufacturers have frequently chosen connectors based on factors of size, cost, or convenience at the expense of compatibility.
card edge connector is the portion of a printed circuit board (PCB) consisting of traces leading to the edge of the board that are intended to plug into a matching socket. The edge connector is a money-saving device because it only requires a single discrete female connector (the male connector is formed out of the edge of the PCB), and they also tend to be fairly robust and durable. They are commonly used in computers for expansion slots for peripheral cards, such as PCI, PCI Express, and AGP cards.
Terminal block is an accessory product used to realize electrical connection, which is divided into the category of connector in industry. With the increasing degree of industrial automation and the stricter and more precise requirements of industrial control, the amount of terminal blocks is gradually increasing. With the development of the electronics industry, the use of terminal blocks is increasing, and there are more and more types. In addition to PCB board terminals, the most widely used ones are hardware terminals, nut terminals, spring terminals and so on. The terminal is used to facilitate the connection of wires. It is actually a piece of metal enclosed in insulating plastic. There are holes at both ends to insert wires. There are screws for fastening or loosening, such as two wires, sometimes Need to connect, sometimes need to be disconnected, then you can use the terminal to connect them, and can be disconnected at any time, without having to solder or twist them together, very convenient and fast. And it is suitable for a large number of wire interconnections. In the power industry, there are special terminal blocks and terminal boxes, all of which are terminal blocks, single-layer, double-layer, current, voltage, common, breakable and so on. A certain crimping area is to ensure reliable contact and to ensure that enough current can pass.
circular connector is a type of connector whose basic structure is cylindrical and has a circular mating surface. In the interconnection classification, it belongs to category 5 and is used for interconnection between devices. Broadly speaking, it includes low-frequency circular connectors, RF coaxial connectors and audio connectors. The cylindrical structure of the circular connector is inherently robust and provides greater strength than any other shape.
Automotive connectors are a component that electronic engineering technicians often touch. Its function is very simple: it sets up a bridge of communication between the blocked or isolated circuits in the circuit, so that the current flows and the circuit realizes the predetermined function. The form and structure of automotive connectors are ever-changing. They are mainly composed of four basic structural components, namely: contacts, shells (depending on the variety), insulators, and accessories. In the industry, it is usually also called sheath, connector, plastic shell. Board-to-board connectors are the connector products with the strongest transmission capacity among all connector product types, mainly used in power systems, communication networks, financial manufacturing, elevators, industrial automation, medical equipment, office equipment, home appliances, military manufacturing and other industries . An IC socket is an integrated circuit socket mounted on a circuit board, characterized by a plurality of electrical contacts arranged in a plurality of cavities. An integrated circuit socket includes an insulating shell, and the insulating shell has an integrated circuit package accommodating groove in which the integrated circuit package is accommodated. The contacts are embedded in cavities arranged in a matrix arrangement in the accommodating grooves of the integrated circuit package.

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  sidalite.com
Geschrieben von: bop16mo - 24.04.2022, 02:45 - Forum: Allgemein - Keine Antworten

Galvanized Light Fixtures, this upscale traditional style fixture can be used on the outside of any home to beautify a porch, deck, patio, garage and more. The anti-flicker high grade Dusk to Dawn photocell automatically turns light on at dusk and turns off the next morning. Simply install it, turn the switch on, and leave it to do its job. This fixture contains a standard medium base (E26) socket and can be adapted to use several styles of light bulbs according to the light and style needs required. It is built to last with reliable quality and a great mix of decorative and functional features such as stainless steel or solid brass mounting hardware and moisture blocking rubber washers. This fixture includes everything you need for a new or to replace an existing light fixture including mounting bracket, junction box screws, corrosion resistant fixture mounting screws and wire nuts. Easy to Install, each fixture comes with full illustrated instructions, making it easy to install for most DIY customers.
The light can be used in commercial areas, residential areas, scenic spots, parks, squares, etc. It can also be used in heavy industrial environments such as marine lighting and external effects. And this kind of light has strong adhesion, heat and cold resistance, clean and environmentally friendly, good safety, stable chemical functions of the raw materials, no harm to the human body. It has anti-rust and oxidation resistance, acid and alkali resistance, and excellent intergranular corrosion resistance. It can be used with confidence in any place and environment.
Good quality outdoor wall lights will allow you to extend the time you can spend outside. They also help to improve security by making it harder for thieves to enter your garden undetected. LED Garden Wall Lights are available in a vast array of styles and finishes, with a number of designs also available with built in security sensors. The combination of PC lampshade and aluminum makes the lamps unique, elegant and sophisticated. Apply PC lampshade to make the light softer, warmer, and protect the eyes. black outdoor lights wall mounted can be applied to unused places, and it is green and environmentally friendly, that is, no heat and no radiation. Using LED light source, compared with incandescent lamps of the same brightness, black outdoor lights wall mounted can save about 80% of electricity. High efficiency, energy saving, environmental protection, recyclable, sturdy and durable, high color temperature, superior color rendering, natural light, no flicker, no glare. In addition to the above, this light is also suitable for anywhere lighting is required.
Outdoor Lawn Lights or garden lighting refers to lights that use outdoor lighting to illuminate private gardens and public landscapes; for the enhancement and purposes of safety, nighttime aesthetics, accessibility, security, recreation and sports, and social and event uses. Light pollution exacerbated by excessive, misdirected or obtrusive use of light, but even carefully used light fundamentally alters natural conditions. As a major side-effect of urbanization, it is blamed for compromising health, disrupting ecosystems and spoiling aesthetic environments.
The public landscape and gardens have been illuminated for as long as interior structures have – for beauty, security, circulation, and social occasions; since ancient times by firelight from wood, candles, and animal-plant oil fells in torches, sconces and lanterns. Since the 17th century's introductions of new interior illumination fuels, the technology has then been used outdoors and in gardens. As systems were developed for power delivery, Gas lighting of the 19th century and electric light of the 20th century became part of exterior functioning and design. Conventionally generated and sourced electricity remains the most used source for landscape lighting in the early twenty-first century. With the combination of increasing demand for more efficient lighting, increasing availability of sustainable designs, global warming considerations, and aesthetic and safety concerns in garden and landscape design the methods and equipment of outdoor illumination have been evolving. The increasing use of LEDs, solar power, low voltage fixtures, energy efficient lamps, and energy-saving lighting design are examples of innovation in the field.
The lights suitable for beautification and lighting decoration in residential communities or public places. Using galvanized or spray paint technology, safe and reliable, energy-saving and environmentally friendly, strong and durable anti-oxidation. This kind of light not only play a lighting effect, bring people a safe and convenient night, but also play a very good green landscape. The soft lighting does not irritate the eyes, but also brings illumination. It can also create a different color atmosphere for the surrounding plants, creating a more eye-catching and beautiful picture, and becoming a beautiful scenery in the city.

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  pino-biotech.com
Geschrieben von: bop16mo - 24.04.2022, 02:41 - Forum: Allgemein - Keine Antworten

vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. The term vitamin does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, there are eight vitamers of vitamin E: four tocopherols and four tocotrienols. Some sources list fourteen vitamins, by including choline, but major health organizations list thirteen: vitamin A (as all-trans-retinol, all-trans-retinyl-esters, as well as all-trans-beta-carotene and other provitamin A carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (phylloquinone and menaquinones).
veterinary drug (also animal drug) refers to a drug intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in animals. Veterinary drugs can be roughly classified into four categories: ① general disease control drugs; ② infectious disease control drugs; ③ internal and external parasitic disease control drugs; ④ (including growth-promoting drugs). Except for biochemical immune products (bacteria, vaccines, serums, antitoxins and toxoids, etc.) for the prevention and treatment of infectious diseases, and special veterinary drugs such as special parasitic drugs for livestock and poultry and growth-promoting drugs, the rest are the same as those for human use, but the dosage , dosage forms and specifications are different. It has long been widely used to control livestock and poultry diseases.
Sweetening agent are food additives that impart sweetness to soft drinks. It can be divided into nutritive sweeteners and non-nutritive sweeteners according to their nutritional value; according to their sweetness, they can be divided into low-sweetness sweeteners and high-sweetness sweeteners; Divided into natural sweeteners and synthetic sweeteners. The main functions of sweetening agent in food are as follows: (1) Taste: Sweetness is one of the indicators of many foods. In order to make food and beverages taste palatable, a certain amount of sweetener needs to be added. (2) For the adjustment and enhancement of flavor, sweetness is generally required in cakes; in beverages, there is a "sugar-acid ratio" for flavor adjustment. Sweeteners allow products to achieve good flavor while retaining fresh flavor. (3) The formation of flavor, sweetness and the flavor of many foods are complementary to each other, and the flavor of many products is produced by the combination of flavor substances and sweeteners, so many foods are added with sweeteners.
Cosmetics are compound mixtures made of various raw materials through reasonable deployment and processing. Cosmetics have a wide variety of raw materials with different properties. According to the raw material properties and uses of cosmetics, it can be roughly divided into two categories: matrix raw materials and auxiliary raw materials. The former is a kind of main raw material of cosmetics, which occupies a large proportion in cosmetic formulations and plays a major functional role in cosmetics. The latter is responsible for shaping, stabilizing or imparting color, fragrance and other properties to cosmetics, which are not used in cosmetic formulations, but are extremely important. Cosmetics are chemical mixtures made of natural, synthetic or extracted substances with different functions as raw materials and processed through production procedures such as heating, stirring and emulsification.
API refers to active pharmaceutical ingredent, includes human growth hormone powder, pure minoxidil powder, paracetamol powder and acetylsalicylic acid powder. It indicate that the raw materials used for the production of various preparations, the active ingredients in the preparations, and various powders, crystals, extracts, etc., prepared by chemical synthesis, plant extraction or biotechnology for medicinal purposes. Substances that the patient cannot take directly.
Natural active ingredient refers to active ingredients extracted from natural products, such as oyster meat powder, bulk krill oil, tomato lycopene extract powder, etc. Chemical products are the species formed from chemical reactions. During a chemical reaction reactants are transformed into products after passing through a high energy transition state. This process results in the consumption of the reactants. It can be a spontaneous reaction or mediated by catalysts which lower the energy of the transition state, and by solvents which provide the chemical environment necessary for the reaction to take place. When represented in chemical equations products are by convention drawn on the right-hand side, even in the case of reversible reactions. The properties of products such as their energies help determine several characteristics of a chemical reaction such as whether the reaction is exergonic or endergonic. Additionally the properties of a product can make it easier to extract and purify following a chemical reaction, especially if the product has a different state of matter than the reactants. Reactants are molecular materials used to create chemical reactions. The atoms aren't created or destroyed. The materials are reactive and reactants are rearranging during a chemical reaction. Here is an example of reactants: CH4 + O2. A non-example is CO2 + H2O or "energy".
Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salting), smoke (smoking), sugar (crystallization), etc. This allows for longer-lasting foods such as bacon, sweets or wines. With the advent of processed foods in the second half of the twentieth century, many additives have been introduced, of both natural and artificial origin. Food additives also include substances that may be introduced to food indirectly (called "indirect additives") in the manufacturing process, through packaging, or during storage or transport.

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  patebathrooms.com
Geschrieben von: bop16mo - 24.04.2022, 02:38 - Forum: Allgemein - Keine Antworten

A basin used for washing, (now) particularly a permanently installed sink, fitted with a water supply and a drain, for washing the hands and face. It can be made of various materials, such as ceramic wash basins that are very common choice among many households in Singapore. Although in recent years, market have been flooded with many different types of bathroom sinks and vanities creating confusion for homeowners on choosing the right products. However, ceramic wash basin are still the most popular choice among most families. Simply because of its core advantages that is irreplaceable. Ceramic have been tested through time and can last really long so there is absoultely no doubt about its durability even after many years of excessive use. It’s resistance to stain makes cleaning easy which is one of the main reasons people choose to use ceramic basins. On top of that, it's eco friendly yet cost effective since not much maintenance is required.
The vanity washbasin enriches the washing area with lots of storage space. Together with the matching furniture, the vanity washbasin gives you an especially elegant and uniform look. The cabinet module and the shelving space ensure plenty of space for daily bathroom utensils. They offer lots of practical and easy to clean shelving space, perfect for a family bathroom as a double washbasin.
The matt color counter top wash basin is resistant to cracks, scratches, fading, heat and wear. The simple design with mat color make luxury bathroom .It is popular in Europe. All the glossy white design can have matt white or matt black color. As well as wall mounted wash basinglossy white counter top wash basin and mable pattern wash basin.
A toilet is a piece of sanitary hardware that collects human urine and feces, and sometimes toilet paper, usually for disposal. Flush toilets use water, while dry or non-flush toilets do not. They can be designed for a sitting position popular in Europe and North America with a toilet seat, with additional considerations for those with disabilities, or for a squatting posture more popular in Asia (see squat toilet). In urban areas, flush toilets are usually connected to a sewer system that leads to septic tanks in isolated areas. The waste is known as blackwater and the combined effluent including other sources is sewage. Dry toilets are connected to a pit, removable container, composting chamber, or other storage and treatment device, including urine diversion with a urine-diverting toilet. The technology used for modern toilets varies. Toilets are commonly made of ceramic (porcelain), concrete, plastic, or wood. Newer toilet technologies include dual flushing, low flushing, toilet seat warming, self-cleaning, female urinals and waterless urinals. Japan is known for its toilet technology. Airplane toilets are specially designed to operate in the air. The need to maintain anal hygiene post-defecation is universally recognized and toilet paper (often held by a toilet roll holder), which may also be used to wipe the vulva after urination, is widely used (as well as bidets).
The wall hung toilet uses an edgeless toilet design, which can effectively prevent dirt from accumulating in the toilet. Since the toilet has no rims, there are no hidden cavities This makes the inner surface much easier to clean compared to a conventional toilet. And compared to conventional PP (Polypropylene) seat covers, UF (Urea-Formaldehyde) seat covers are high quality and scratch-resistant. UF seat covers are easy to clean and do not lose their shine even after years of use. At the same time, due to the different surface materials, this toilet can be divided into matt color wall hung toilet and glossy white wall hung toilet.
dual flush toilet is a variation of the flush toilet that uses two buttons or a handle mechanism to flush different amounts of water. A lesser amount of water is designed to flush liquid waste and the larger quantity of water is designed to flush solid waste. The system was developed by Japanese sanitary product manufacturer TOTO in 1960. It was equipped with two levers and built-in hand-washer, and was also revolutionary in that it reused the water in the hand-washer for flushing. However, it was not well known outside, or even within, Japan. In 1976, American industrial designer Victor Papanek proposed the dual flush system in his book Design for the real world, but the first practical implementation was designed in 1980, by staff at the Australian sanitary-ware company Caroma, with flush volumes of 11 and 5.5 litres. The design caught on, and a redesign in 1994 cut water usage to 6 and 3 litres. The dual-flush toilet has become almost universally adopted in Australia, New Zealand, Singapore, and Israel, with its use in new buildings often mandated by legislation in those countries. The more complex dual-flush mechanism is more expensive than many other types of low-flush toilets. A typical flush toilet is a ceramic bowl (pan) connected on the "up" side to a cistern (tank) that enables rapid filling with water, and on the "down" side to a drain pipe that removes the effluent. When a toilet is flushed, the sewage should flow into a septic tank or into a system connected to a sewage treatment plant.
Toilets are an integral part of any bathroom. Whether you’re in the midst of a remodel or your old toilet is leaking and needs replacing, you'll be faced with several options when choosing a new bathroom fixture. Toilets come in many shapes, sizes, and styles, including one-piece and two-piece toilets. Traditionally, toilets were made with a tank and bowl bolted together, and some are still sold this way. However, recently one-piece toilets have become an option. A two piece toilet has a separate tank and bowl, while a one piece is all connected. But there are other differences, too. One piece toilets are typically heavier and easier to clean, and there’s less space for bacteria to grow. Because two piece toilets feature a detachable tank, they're more customizable for preferred styles and heights. Both styles can include bells and whistles like bidet attachments or low-flow energy saving. Also, either can be shaped in the standard styles: elongated, which is slightly longer, and round. Because one piece toilets are heavier, they can be more expensive to ship if you order one online. Both toilets work well.

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  meixin-dg.com
Geschrieben von: bop16mo - 24.04.2022, 02:35 - Forum: Allgemein - Keine Antworten

headband is a clothing accessory worn in the hair or around the forehead, usually to hold hair away from the face or eyes. Headbands generally consist of a loop of elastic material or a horseshoe-shaped piece of flexible plastic or metal. They come in assorted shapes and sizes and are used for both fashion and practical or utilitarian purposes. In the UK, horseshoe-shaped headbands are sometimes called "Alice bands" after the headbands that Alice is often depicted wearing in through the Looking-Glass. There are many materials used for headbands such as wood, leather, plastic, metal, fabric, hemp, teeth, human and animal hair, bone, and novelty materials. The leather headbands are usually glued onto a harder plastic headband, or they are hand-stitched. Plastic headbands, which are most common, can be wavy, straight or angled and come in many colours. Metal can be used to form and support leather headbands. Metal-only headbands may be plain or decorated, sometimes with precious jewels. Fabric headbands are comfortable because they do not dig into the head. They usually have an elastic band, so that the headband forms to the head. Toothed headbands have comb-like teeth that are connected to the top part of the headband. Their teeth ensure that the hair stays in place.
Makeup headband could keep the hair looking fresh while brushing the teeth, washing the face, applying makeup or even in a quick shower. They are ideal for taming those flyaways whilst doing your makeup, stopping a face mask going in your hair, and just generally keeping your hair out of your way during your everyday make-up and skincare routines.
Headbands, or sport headbands, are worn around the forehead during physical activity to absorb sweat and keep it from reaching the eyes. Sweatbands are often made of a continuous loop of terrycloth, as it is a particularly absorbent fabric. Folded bandanas, usually knotted behind the head, also serve this purpose. Headbands are usually used for sports but have not been popular since the late 1970s or early 1980s. LeBron James is one of the most notable players who wears a headband during basketball games. They also come in the form of wristbands.
Hair claws, as the term suggests, are hair clips that are shaped like claws. Basically, two claws are joint together by means of a spring, which helps to open and close the claw clip while also holding the hair firmly. Due to their shapes, hair claw clips enjoy a considerable reputation when it comes to following trendy fashion and hairdos. Hair claw clips are also known as hair jaws. Hair claws are ideal for on-the-go and easy hairstyles. This hair accessory is pretty classy yet straightforward. It offers you an excellent alternative to don a formal updo or casually holding the hair at one place for carrying out home chores. Their versatility is the reason why women drool over them. Owing to their widespread popularity, millions of hair claw clips are embellishing the hairstyles of women across the globe. Although it seems pretty simple to put on a hair claw since all you need to do is pressing the rear end of the claw clip to open its jaws and attach them to the hair. The material of hair claws can be divided into many kinds, such as plastic hair clawsmetal hair claws, etc.
The face mask is a kind of hygiene product, which is generally worn on the mouth and nose to filter the air entering the mouth and nose to block harmful gases, odors, droplets, viruses and other substances. It is made of gauze or paper and other materials. Masks have a certain filtering effect on the air entering the lungs. Wearing masks has a very good effect when working in a polluted environment such as dust when respiratory infectious diseases are prevalent. Masks can be divided into air filter masks and air supply masks. It can also be divided into disposal facemaskscotton facemasks and silk facemasks according to the material. But compared with the latter two, disposal facemasks are more hygienic and safer in the current situation of COVID-19.
scarf, plural scarves, is a piece of fabric worn around the neck or head for warmth, sun protection, cleanliness, fashion, religious reasons, or used to show the support for a sports club or team. They can be made in a variety of different materials such as wool, linen, silk or cotton. It is a common type of neckwear. Scarves have been worn since ancient times. The Statue of Ashurnasirpal II from the 9th century BC features the emperor wearing a shawl. In Ancient Rome, the garment was used to keep clean rather than warm. It was called a focale or sudarium (sudarium from the Latin for "sweat cloth"), and was used to wipe the sweat from the neck and face in hot weather. They were originally worn by men around their neck or tied to their belt.
In later times, scarves were also worn by soldiers of all ranks in Croatia around the 17th century. The only difference in the soldiers' scarves that designated a difference in rank was that the officers had silk scarves whilst the other ranks were issued with cotton scarves. Some of the Croatian soldiers served as mercenaries with the French forces. The men's scarves were sometimes referred to as "cravats" (from the French cravate, meaning "Croat"), and were the precursor of the necktie. The scarf became a real fashion accessory by the early 19th century for both men and women. By the middle of the 20th century, scarves became one of the most essential and versatile clothing accessories for both men and women. Scarves can be divided into hijab scarffashion scarfsoccer scarfsilk scarf and so on.
hat&cap is a head covering which is worn for various reasons, including protection against weather conditions, ceremonial reasons such as university graduation, religious reasons, safety, or as a fashion accessory. In the past, hats were an indicator of social status. In the military, hats may denote nationality, branch of service, rank or regiment. Police typically wear distinctive hats such as peaked caps or brimmed hats, such as those worn by the Royal Canadian Mounted Police. Some hats have a protective function. As examples, the hard hat protects construction workers' heads from injury by falling objects, a British police Custodian helmet protects the officer's head, a sun hat shades the face and shoulders from the sun, a cowboy hat protects against sun and rain and an ushanka fur hat with fold-down earflaps keeps the head and ears warm. Some hats are worn for ceremonial purposes, such as the mortarboard, which is worn (or carried) during university graduation ceremonies. Some hats are worn by members of a certain profession, such as the Toque worn by chefs. Some hats have religious functions, such as the mitres worn by Bishops and the turban worn by Sikhs. Also, it can be divided into bonnetsbeaniesports caps, etc.

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  kt-fasteners.com
Geschrieben von: bop16mo - 24.04.2022, 02:30 - Forum: Allgemein - Keine Antworten

bolt is a form of threaded fastener with an external male thread requiring a matching pre-formed female thread such as a nut. Bolts are very closely related to screws. Bolts are designed to pass through an unthreaded hole in a component and be fastened with the aid of a nut, although such a fastener can be used without a nut to tighten into a threaded component such as a nut-plate or tapped housing. They are often used to make a bolted joint. This is a combination of the nut applying an axial clamping force and also the shank of the bolt acting as a dowel, pinning the joint against sideways shear forces. For this reason, many bolts have a plain unthreaded shank (called the grip length) as this makes for a better, stronger dowel. The presence of the unthreaded shank has often been given as characteristic of bolts vs. screws, but this is incidental to its use, rather than defining.
Bolts use a wide variety of head designs, as do screws. These are designed to engage with the tool used to tighten them. Some bolt heads instead lock the bolt in place, so that it does not move and a tool is only needed for the nut end. Many bolts use a screwdriver head fitting, rather than an external wrench. Screwdrivers are applied in-line with the fastener, rather than from the side. These are smaller than most wrench heads and cannot usually apply the same amount of torque. It is sometimes assumed that screwdriver heads imply a screw and wrenches imply a bolt, although this is incorrect. Coach screws are large square-headed screws with a tapered wood screw thread, used for attaching ironwork to timber. Head designs that overlap both bolts and screws are the Allen or Torx heads; hexagonal or splined sockets. These modern designs span a large range of sizes and can carry a considerable torque. Threaded fasteners with screwdriver-style heads are often referred to as machine screws whether they are being used with a nut or not. There are many types of bolts, such as hex bolt - Bolt with a hexagonal head and threaded body. Section immediately under head may or may not be threaded; carriage bolt - Bolt with a smooth rounded head and a square section to prevent turning followed with a threaded section for a nut; anchor bolt - Bolt designed to allow objects to be attached to concrete. The bolt head is usually placed in concrete before it has cured or placed before the concrete is poured, leaving the threaded end exposed; U-bolt - Bolt shaped like the letter U where the two straight sections are threaded. A straight metal plate with two bolt holes is used with nuts to hold pipes or other round objects to the U-bolt.
Flange bolts have a circular flange under the head that acts like a washer to distribute the load. Flange bolts that are non-serrated are sometimes called frame bolts. A flange bolt differs from the common bolt in that it has a wider surface area under the head to provide for an even distribution of clamping pressure. This wider surface acts like a washer, eliminating the need to combine one with this kind of bolt. Flange bolts are available in numerous sizes, strengths, and configurations. Like most other types of fasteners on the market, metric flange bolts are available for any applications that require them. Specially designed flange bolts are equipped with anti-rotational “teeth” designed to “bite” or dig into the material one might need to fasten together. Similar to the locking rings one might see on a soda bottle or milk jug, these teeth on the flange bolt can be turned backward, but often require more force. This type of design is what makes a flange bolt uniquely and strategically different from a common bolt.
Hexagon socket bolts with cylindrical head are also referred to as hexagon socket bolts, cup-head screws, and hexagon socket screws. The names are different, but the meaning is the same. Commonly used hexagon socket head screws also have 4.8, 8.8, 10.9, and 12.9. Also called hexagon socket screws, also called hexagon socket bolts. Its head is hexagonal and cylindrical. According to the material, there are stainless steel and iron. There are stainless steel SUS202 hexagon socket head cap screws. This is a common stainless steel material. There are stainless steel SUS304 hexagon socket cap screws and stainless steel SUS316 hexagon socket cap screws. The iron is classified according to the strength grade of the hexagon socket head screw. There are 4.8 grade hexagon socket head screws, 8.8 grade hexagon socket head screws, 10.9 grade hexagon socket head screws, and 12.9 grade hexagon socket head screws. Grade 8.8-12.9 hexagon socket head cap screws are called high-strength, high-grade hexagon socket bolts.
Stud bolts, also known as double-headed screws. It is used to connect the fixed link function of the machine. The stud bolt has threads at both ends, and the screw in the middle is thick or thin. Generally used in mining machinery, bridges, automobiles, motorcycles, boiler steel structures, pendant towers, long-span steel structures and large buildings. And square bolts are now most commonly used for aesthetic purposes to provide a rustic look in a new structure or to match existing fasteners in an older structure. Square lag screws are also used for these purposes. Crossarm or machine bolts are commonly supplied for the utility industry and included an added cone point. Expansion bolts can be used to secure heavy objects to walls or floors and handle vertical and horizontal loads. By tightening the bolt, the nut on the opposite end pulls into the shell, expanding it outward and wedging it inside the hole in the wall or floor. It requires a spanner or socket wrench to fasten or undo the bolt and ideal for heavy duty fastening of steel and wood structures walls and floors.
Nuts, parts that are screwed together with bolts or screws for fastening, are a kind of original that must be used in all production and manufacturing machinery. According to different materials, it is divided into several types such as carbon steel, stainless steel, non-ferrous metals (such as copper). Nuts are parts that tightly connect mechanical equipment. Through the inner threads, nuts and bolts of the same specification can be connected together. For example, M4-P0.7 nuts can only be connected with M4-P0.7 series bolts (in the nut). Among them, M4 means the inner diameter of the nut is about 4mm, and 0.7 means that the distance between the two threads is 0.7mm); the same is true for American products, for example, a 1/4-20 nut can only be matched with a 1/4-20 screw ( A 1/4 finger nut has an inner diameter of about 0.25 inches, and 20 fingers have 20 teeth in each inch).
The hexagonal nut is used in conjunction with screws, bolts and screws to connect and fasten parts. Among them, the Type 1 six-purpose nut is the most widely used. The C-level nut is used for machines, equipment or structures with rough surface and low precision requirements; A-level and B-level nuts are used for relatively smooth surfaces and high precision requirements. machine, equipment or structure. The thickness M of the type 2 hexagon nut is thicker, and it is mostly used in occasions where assembly and disassembly are often required. The thickness M of the hexagonal thin nut is relatively thin, and it is mostly used in situations where the surface space of the connected parts is limited.
The flange nut is a nut with a wide flange on one end that acts as an integral washer. This serves to distribute the pressure of the nut over the part being fastened, reducing the possibility of damage to the part and making it less likely to loosen due to uneven tightening surfaces. These nuts are mostly hexagonal in shape and are made of hardened steel, usually plated with zinc.
In many cases, the flange is fixed and turns with the nut. The flanges may be serrated to provide locking. The serrations are angled so that the nut does not rotate in the same direction as the nut is loosened. Because of the serrations, they cannot be used with washers or on scratched surfaces. The serrations help prevent the vibration of the nut from moving the fastener, thus maintaining the retention force of the nut. Flange nuts sometimes feature rotating flanges that help create a more stable structure without affecting the finished product like serrated flange nuts. Swivel flange nuts are mainly used to join wood and plastic. Sometimes both sides of the nut are serrated, allowing either side to lock. Self-aligning nuts have male spherical flanges that mate with female dish washers to allow the nut to tighten on surfaces that are not perpendicular to the nut. A spring cushion is installed under the nut to prevent the nut from loosening.

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  firstkissthermos.com
Geschrieben von: bop16mo - 24.04.2022, 02:27 - Forum: Allgemein - Keine Antworten

The coffee mug is sintered from negative ion powder, tourmaline, high-quality clay and other basic materials. The high concentration of negative ions released from the high coffee mug can electrolyze the water to generate negatively charged hydroxide ions, making the macromolecules in the water smaller and enhancing the solubility and penetration of water. Therefore, the drinking water in the coffee mug has a stronger dissolving ability for the beverage, and the beverage effect is better. Pouring water into a coffee cup can increase the activity of water, regulate human endocrine, adjust the balance of yin and yang in the human body, promote metabolism, improve human microcirculation, and have good medical and health care effects on relieving various diseases. There are many kinds of materials for coffee cups, such as pottery, stainless steel, bone china and so on. Porcelain and pottery are both glazed and fired. The texture of pottery is relatively rough and slightly absorbent. If the glaze falls, that part will be easily polluted and cannot be washed off; The bone china cup has good thermal insulation, which can keep the coffee warm in the cup, but the price is very high; the double-layer stainless steel cup has high thermal insulation, durable and will not be worn, and the price is slightly better than that of bone china coffee.
Stainless steel is designed to resist reaction with the weak acids that we use for cooking. Stainless steel tumblers could be used to keep homemade lemonade cold and you can be sure that no reaction will occur. Stainless steel keeps your liquids tasting good and there is no transfer of odor. Stainless steel has long-life properties inherent in it and these properties don't diminish over time or with repeated use. It also features an excellent strength-to-weight ratio, meaning that even very light steel is still very strong, especially when you compare it to alternatives like different grades of aluminum, polystyrene, plastics, or glass. In fact, glass and ceramic containers (which are popular alternatives to steel) are so unstable that they're actually banned in many venues and events for health and safety reasons. Meanwhile, aluminum is susceptible to corrosion and pinhole leaks and bottles made with it typically have interior linings that can disintegrate over time. Petroleum-based plastics easily crack and degrade with repeated uses, washing, and exposure.
Recent discoveries regarding toxic chemicals in drinkware, such as BPA and Phthalates, have set the entire health community buzzing. These toxins are typically found in plastic containers, as well as in the lining of many aluminum bottles. This has made stainless steel the best option for the health-conscious outdoorsman, where insulated cups with lids are popular. Steel is an alloy that's composed of all-natural elements, therefore it's non-toxic and free of nasty elements like BPA, lead, and zinc. These all can lead to conditions like cancer and endocrine disruption. Thanks to its inherent antibacterial and hygienic properties, stainless steel has been widely used in the food and medical industries for years, even in the most critical of sanitary environments. Stainless steel is also non-reactive to acidic beverages and it offers a clean, neutral taste that won't affect the smell or flavor of your drinks. And there are stainless steel wine tumbler, the best way to enjoy your favorite wines. They keep drinks cold for up to 24 hours, and hot beverages stay warm for 12 hours or more. The double-walled vacuum insulation prevents condensation on the exterior of the cup so you can easily hold it without getting wet; stainless water bottleone touch bottle and mini flask as well.
The outdoor jug is a jug carried during outdoor sports. It has become a basic configuration for outdoor enthusiasts because of its durability, safety, reliability, convenience and insurance, and the ability to choose patterns of different colors and styles according to personal preferences. As a tool for carrying water, the kettle has a simple structure and is convenient to carry. This outdoor kettle adopts a double-layer vacuum design, which can keep warm and cold for 24 hours; with a large-capacity design, it is necessary for outdoor sports and family travel; its strap and TPR soft rubber handle are designed to be portable and easy to carry; the design of the cup cover makes It is more convenient to drink water; in addition, you can customize the color and LOGO design.
The soup cup consists of thermos food pot, thermal soup cup & pot, insulated soup pot. It adopts a double-layer vacuum design, which can keep warm and cold, and has an automatic exhaust design, that the lid can be easily opened after loading hot food. Also it can hold various foods such as soup and porridge, and the large diameter is easy to clean; in addition, you can customize the color and LOGO design.

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  bon-natural-life.com
Geschrieben von: bop16mo - 24.04.2022, 02:24 - Forum: Allgemein - Keine Antworten

Mixtures of aromatic compounds of flavors and fragrances preparations (in some cases a single compound) of aroma compounds that impart a specific aroma to various consumer products. There are several products it includes, such as Ambroxide Ambroxan, synthesized from sclareol, with a special ambergris fragrance, is used as a fixative for perfume and cosmetic essence and often it used as a perfuming agent and a fixative for soap, talcum powder, cream, shampoo and a perfuming agent for blended cigarettes; Natural Sclareol 95% & 98%, sclareol is white crystalline powder extracted from natural Labiate salvia sclarea. It has a faint delicate amber fragrance with strong diffusivity and lasting smell, which can give vivid, harmonious and lasting fragrance to essence. It is mainly used in synthesizing substitutes for natural ambergris such as sclareolide and ambroxide, and is less used in preparing essence; Pure Clary Sage Oil, Pure Lavender Essential Oil, Stachyose Prebiotic and Pure Ferulic Acid Powder.
dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order to increase the quantity of their consumption. The class of nutrient compounds includes vitamins, minerals, fiber, fatty acids, and amino acids. Dietary supplements can also contain substances that have not been confirmed as being essential to life, but are marketed as having a beneficial biological effect, such as plant pigments or polyphenols. Animals can also be a source of supplement ingredients, such as collagen from chickens or fish for example. These are also sold individually and in combination, and may be combined with nutrient ingredients. The European Commission has also established harmonized rules to help insure that food supplements are safe and appropriately labeled. Creating an industry estimated to have a 2020 value of $140.3 billion, there are more than 50,000 dietary supplement products marketed in the United States, where about 50% of the American adult population consumes dietary supplements. Multivitamins are the most commonly used product among types of dietary supplements. The United States National Institutes of Health states that supplements "may be of value" for those who are nutrient deficient from their diet and receive approval from their medical provider.
The principal raw materials used for manufacturing cosmetics are oily materials such as oils, fats, wax esters, and ester oils, and surface-active agents are used as emulsifiers, solubilizing agents, etc. Humectants, thickening agents, film formers as well as polymers are used as powders, ultraviolet absorbents, antioxidants, sequestering agents, coloring agents such as dyes and pigments, along with vitamins, pharmaceutical agents such as plant extracts and perfume. Oil has the ability to dissolve fats and is widely used as a component of cosmetics. Oily materials control the evaporation of moisture from the skin and are used mainly to improve the feeling on use. The solute in a solution can be adsorbed to a gas–liquid, liquid–liquid, or liquid–solid surface. These remarkable changes in the properties of surfaces are called surface activity and the so-called surface-active agents are materials demonstrating unusual surface activity. This surface activity is exploited in emulsification, solubilization, permeation, wetting, dispersion, cleansing, etc. Cosmetic Raw Materials is based on various materials and ingredients perform in accordance to the chemicals and its key functionalities. The properties and uses of the cosmetic materials are generally possible to be divided into two categories. The first is the principal raw ingredient of cosmetics. The primary function of cosmetics is that they are made in large proportion in cosmetic preparations. These substances play a role in a number of cosmetic formulations, stable or given colour, aroma, and other characteristics, but they are vital. Natural cosmetics raw materials are available for every product.
Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", and the majority of its treatments as having no logical mechanism of action. It has evolved over thousands of years. TCM practitioners use various psychological and/or physical approaches (such as acupuncture and tai chi) as well as herbal products to address health problems.
TCM extract is a kind of traditional Chinese medicine product with a relatively clear medicinal effect and strict quality standard, which is obtained by using advanced technology to extract, separate and process traditional Chinese medicinal materials or traditional Chinese medicine compounds. A new product form, it is the main raw material of botanical preparations and can be widely used in natural health products. According to the nature of the extracts, it can be divided into four categories: single herbal extracts (using different extraction methods) such as Ganoderma lucidum, ginseng, ginkgo biloba, Luo Han Guo, Xianrencao, etc.; compound herbal extracts such as Buzhong Yiqi Decoction, Sishen Soup, Liuwei Dihuang Pill, Qibao Meiran Dan, Xiaoyao Powder, etc.; Chinese medicine monomers such as ginkgo flavonoids, ginkgolides, soybean isoflavones, Ganoderma lucidum polysaccharides, cordycepin, etc.; derivatives of Chinese medicine extracts such as indigo red of Qingdai, about this One point is still controversial. The chemical composition of the standard extract of traditional Chinese medicine is usually a group of active ingredients composed of a variety of pharmacologically active substances in a certain proportion. Control has considerable advantages.

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  allychem.com
Geschrieben von: bop16mo - 24.04.2022, 02:20 - Forum: Allgemein - Keine Antworten

Arylboronic acids are important reagents for the construction of carbon-carbon bonds and carbon-heteroatom bonds. Especially, arylboronic acid esters have the advantages of high stability, low toxicity, and easy operation, and are widely used in the synthesis of drugs and active natural products. .In addition, in biology, material science and medical research, arylboronic acids have been widely used in carbohydrate sensors, enzyme inhibitors and nucleoside and carbohydrate transport carriers. Therefore, the development of efficient and mild aromatic The synthesis method of boronic acid has always been the focus of chemists. The cross‐coupling of arylboronic acids and derivatives with DAST‐type reagents under mild and metal‐free conditions to directly afford sulfinamides in moderate to good yields. Moreover, sulfonamides were obtained after a simple oxidation reaction. The reaction mechanism was investigated by 18O‐labeling experiments, and the synthetic utility was demonstrated by the sulfoxidation of natural products.
Bis(pinacolato)diboron is widely used in the catalytic monoboration and diboration of carbon–carbon multiple bonds. Although known for over 90 years, only in the past two decades has the chemistry of diboron compounds been extensively explored. Many interesting structural features and reaction patterns have emerged, and more importantly, these compounds now feature prominently in both metal-catalyzed and metal-free methodologies for the formation of B–C bonds and other processes.
Organoboric acid is a class of organoboron compounds with the general formula R-B(OH)2, also known as hydrocarbyl boronic acid. It is a product in which one hydroxyl group of boronic acid (B(OH)3) is replaced by an organic group. Organoboronic acid is more stable than its inorganic acid parent (HB(OH)2), but it can still be hydrolyzed under acidic conditions to generate boronic acid. Organoboronic acid has important applications in organic synthesis, such as Suzuki coupling reaction. Due to their versatility as synthetic intermediates in the preparation of complex molecules, boronic acids and derivatives play important roles in organic synthesis and medicinal chemistry.
Potassium trifluoroborates are a special class of organoboron reagents that offer several advantages over the corresponding boronic acids and esters in that they are moisture- and air-stable, and are remarkably compliant with strong oxidative conditions. Sodium tetrafluoroborate is an inorganic compound with formula NaBF4. It is a salt that forms colorless or white water-soluble rhombic crystals and is soluble in water (108 g/100 mL) but less soluble in organic solvents. Sodium tetrafluoroborate is used in some fluxes used for brazing and to produce boron trifluoride. Potassium Trifluoroborate and Tetrafluoroborate Salts are both a class of compounds with the anion BF4−.
Chiral compounds refer to the same molecular weight and molecular structure, but the left and right arrangements are opposite, such as the real object and its enantiomer in the mirror. Human's left and right hands have the same structure, and the order from the big to the little finger is also the same, but the order is different. The left hand is from left to right, and the right hand is from the opposite, so it is called "chirality". That is, a pair of molecules. A chiral compound can contain no improper axis of rotation (Sn), which includes planes of symmetry and inversion center. Chiral molecules are always dissymmetric (lacking Sn) but not always asymmetric (lacking all symmetry elements except the trivial identity). Asymmetric molecules are always chiral.
Alkylboronic acids such as methylboronic acid and butylboronic acid are highly active catalysts for the dehydrative amide condensation of α-hydroxycarboxylic acids. The catalytic activities of these alkylboronic acids are much higher than those of the previously reported arylboronic acids. Alkenyl and alkyl acids are substituted boronic acids with carbon-boron bonds, represented by R-B(OH)2. These Lewis acids are "green" compounds due to their inherent low toxicity and rapid environmental degradation. We provide high quality alkenyl acids for alkylboronic acid derivative formation and other chemical synthesis applications.
Alkenyl boronic acids are important organic synthons that are widely used in the preparation of high value-added alkenyl compounds and multifunctional alkyl boronic acid esters. Cross-coupling or lithium-halide exchange-boration reactions of alkenyl halides and their analogs are a common method for preparing alkenyl boronic esters. However, the alkenylboronic acids derivatives and their analogs are relatively expensive and complicated to prepare, which limits the general use of this method to a certain extent. Hydroboration and carboration of alkynes are another commonly used method for the preparation of alkenyl boronic esters. However, most of the hydroboration reactions of terminal alkynes can only produce 1,2-disubstituted alkenyl boronate esters, and rarely 1,1-disubstituted alkenyl boronate esters; hydroboration of asymmetric internal alkynes or carbon The boronation reaction lacks practical value due to the lack of regioselectivity.
Due to their versatility as synthetic intermediates in the preparation of complex molecules, boronic acids and boronic acid derivatives play important roles in organic synthesis and medicinal chemistry. Boric acid is also one of the basic raw materials for the production of other borides, such as heterocyclic boronic acids and derivativesother compoundsintermediate and so on.

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