7-(iodomethyl)pentadecane

"Tiangong Kaiwu" has a saying: "Those who have five catties of ten are refined into brass with furnace sweet (calamine) and other medicines, and its color is like gold." Fifteen catties of copper is a good material for castings. Its main use is covered with the following ends.
One is used for coinage. Money is the blood of economic circulation. Brass coinage is solid in texture, not easy to wear and tear, and beautiful in quality. It is easy to carry and count. It is indispensable for merchants' transactions and tax collection. Since the Han Dynasty, many dynasties have used brass to mint coins to stabilize the economy and promote trade.
Second, it is cast as an appliance. Brass has good thermal conductivity, so it is mostly used to make cooking utensils such as pots and kettles, stoves, etc. It is durable and not easy to rust, and can be used for cooking by the people for a long time. Furthermore, it is also used in the manufacture of lamps, candlesticks and other lighting utensils, which are not only beautiful and elegant, but also sturdy and durable, providing convenience for night lighting.
Third, carved handicrafts. Brass is golden in color and warm in texture. Craftsmen use it as a material to carefully carve and make ornaments, accessories and other handicrafts. Or it is an exquisite bird and beast, or a lifelike figure, or an exquisite decoration. It has ornamental value and can show the status. It is loved by dignitaries, literati and scholars.
Fourth, it is used for architectural decoration. In palaces, temples, gardens and other buildings, brass is often used to make door knockers, handles, decorative components, etc. Its golden light shines, adding to the solemnity of the building, showing the royal majesty, the sanctity of the temple, and the elegance of the garden.
In short, fifteen catties of brass play an important role in many fields such as currency, utensils, craftsmanship, and architecture, bringing many conveniences and beauty to the development of ancient society and people's lives.

"Tiangong Kaiwu" is a scientific and technological masterpiece written by Song Yingxing in the Ming Dynasty. However, it does not mention the "fifteen chickens" in it, or because the expression is wrong, it answers with the common characteristics of "stone sulfur yellow" (ie sulfur).
Stone sulfur yellow, pure yang in nature, its quality is formed by the essence of things. The color is yellow and brittle, and it burns when it touches fire. The flame is blue-purple, and it has a pungent smell.
Its sex is hot and poisonous. In the way of medicine, it can be used externally to kill insects, treat scabies, and treat acne. Because it can dry dampness, kill insects, and relieve itching, it can get rid of skin diseases. However, it is poisonous, and it should be taken internally with caution. If it exceeds the amount, it will cause harm.
In the art of alchemy, stone sulfur yellow is also an important medicine. The ancients believed that it has magical power, can transform hardware, alchemy medicine, and seek longevity. Although today I know the delusion of longevity, it has contributed greatly to the evolution of alchemy.
For industrial use, stone sulfur yellow can be used to make sulfuric acid, which is the foundation of chemical industry. It is also used for rubber vulcanization, making rubber tough and wear-resistant, and has a wide range of uses.
Stone sulfur yellow is strong and toxic, so use it carefully, take its advantage and avoid its harm, so that it can be used as much as possible.

Hepta- (methyl) pentadecane is an organic compound with relatively stable chemical properties.
This compound is composed of a long carbon chain, and the methyl group is connected to the main chain of pentadecane as a side chain. Because of its long carbon chain and strong intermolecular van der Waals force, the melting boiling point is relatively high. Under normal temperature and pressure, it is mostly liquid or solid.
In terms of chemical activity, hepta- (methyl) pentadecane is generally difficult to undergo addition reactions due to carbon chain saturation. Under normal conditions, it is relatively stable to acids, bases, common oxidants and reducing agents. However, at high temperature, high pressure and in the presence of suitable catalysts, cracking reactions can occur, and the carbon chain breaks to form hydrocarbons with shorter carbon chains.
In addition, under light or heating conditions, the hydrogen atoms in heptadecane can be replaced by halogen atoms to undergo halogenation reactions. However, such reactions require specific reaction conditions and initiators to proceed smoothly.
Overall, heptadecane has relatively stable chemical properties and is not easy to participate in chemical reactions under common conditions. The stability makes it suitable for use as a stable basic raw material or additive in many fields.

"Tiangong Kaiwu" has a saying: "Where a mirror is cast, gray sand is used for the mold, and tin and copper are used, and lead is not used." The method of casting a mirror is to use copper as the main one, supplemented by other things, to make a tool. For the copper of the casting mirror, refined copper is often selected. There are few impurities and the texture is pure. This is the foundation of the casting mirror.
As for the ingredients of the casting mirror, tin is indispensable. Tin and copper are combined to change the characteristics of copper. Adding an appropriate amount of tin can make the texture of the bronze mirror harder, and after polishing, it can be used to learn from people. For example, "Kaogong Ji" says: "There are six pieces of gold, and half pieces of gold and tin, which is called the unity of the beacon." This is the experience of the ancients in casting mirrors. It is said that half of copper
When casting a mirror, it is also crucial to grasp the heat. If the fire is too fierce, the copper and tin are easy to evaporate and the ratio is inaccurate; if the fire is insufficient, the copper and tin will be difficult to fuse and the mirror quality will be poor. Craftsmen need to rely on experience to observe the changes in the heat and adjust it in a timely manner.
In addition, the casting mold is also exquisite. Using gray sand as a mold, because of its good air permeability, can make the mirror body cool evenly and reduce air bubbles and trachoma. When making the mold, carefully carving and clear decoration can make the bronze mirror both practical and beautiful.
After the casting mirror is completed, polishing is also an important process. Fine stone, flannel, etc. need to be used to polish repeatedly to make the mirror surface as smooth as a mirror, in order to show the delicacy of the casting mirror. This is the method of casting mirrors, and the wisdom of the ancients can be seen here.

Five out of ten dogs should pay attention to everything during storage and transportation. First, the placement of the dog needs to be proper. It is advisable to prepare a clean and soft place so that the dog can sleep peacefully, and do not let it be pressed or squeezed to prevent injury to the body. Second, the temperature and humidity should be appropriate. Cold can easily cause diseases in dogs, and heat can make dogs unbearable. Therefore, it is necessary to check the temperature and humidity of the environment and adjust it in time. If it is cold, it can increase the felt blanket, and if it is hot, it needs to be ventilated and cooled. Third, there is no shortage of drinking water. During the journey, the dog must be provided with sufficient food and clear water to maintain its physical fitness, and the drinking water must be changed frequently to prevent filth and evil. Fourth, to prevent disturbance. The dog is sensitive, noisy or abnormal, and it is easy to make it panic, so keep the environment quiet, and do not let the dog be disturbed and cause confusion. Fifth, cleanliness should not be ignored. Regularly remove filth to keep the dog's body and place clean and free from diseases. And when transporting, you should also pay attention to the movement of the dog. If there is any discomfort, you should deal with it quickly, so that the dog can be safely stored and transported.