3-bromo-2-iodopyridine

"Tiangong Kaiwu" is an important scientific and technological work in ancient China. Its main uses can be viewed from many aspects in the content of "3-liquid-2 question type".
The first to bear the brunt is to record the knowledge of the process. "Tiangong Kaiwu" records in detail the transformation of various substances from liquid state to liquid state and other processes, such as the treatment of metal melt during metal smelting. The characteristics of liquids, operating conditions and product effects are described in detail, providing precious materials for future generations to inherit and study ancient crafts. For example, in the coin casting process, the preparation of copper liquid and the control of casting temperature are all related to the quality of coins. These records help future generations to clarify ancient exquisite skills.
Furthermore, it has scientific research value. The observation and analysis of liquid-related phenomena in the book reflects the level of scientific cognition at that time. For example, the description of some liquid chemical reactions provides clues for the study of chemical history. By exploring the ancient understanding of liquid substances, we can gain insight into the development of ancient science, which is of great significance for the construction of scientific history.
In addition, it provides reference for production practice. It records many practical production technologies, such as brine extraction and treatment in salt making processes. In today's traditional process inheritance or specific production fields, these ancient methods are still of practical value and can provide ideas for production optimization and quality improvement.
"Tiangong Kaiwu" is of great significance in the documentation of liquid-related knowledge, whether in process inheritance, scientific research or production practice. It is an important embodiment of ancient Chinese scientific and technological civilization and lays a solid foundation for future development.

The synthesis method of 3-2-3-2-3-3-2-3-3-3-3-3-2-1 can be divided into fabrication, fabrication, mechanical processing, etc. Each method has its own advantages and disadvantages, and the use of the balance.
The method of fabrication is to melt the gold into a liquid, and then put it into the mold, and wait for it to solidify and form. This method is used in the molding of 3-2-2-3, which can be produced in large quantities, and the cost is low. However, the parts may have defects such as holes and sparsity, which need to be dealt with. For example, "All the tools must be molded first, and the soil or wood must be melted into gold." The key to the fabrication is to control the degree of melting, the speed of injection, and the transparency of the molds.
Manufacturer, the metal billet is applied with force to make it plastic-shaped, with the desired shape properties. The manufacturing can improve the quality of the metal and improve its performance. For 3-2-2, if you need to withstand a large external force, the manufactured product is better. The method is as said in "Tiangong Materials": "Where the properties are bonded one by one, it is bonded with mud dregs into the fire." Through reverse coating and beating, the gold is dense and uniform. However, the manufacturing requirements are high, and the production efficiency is low.
Mechanical processing is to process the metal material into 3-2-2 by means of cutting, grinding, etc. This method can achieve high precision and good surface roughness, and is used for the combination of dimensional accuracy and surface roughness requirements. According to the requirements, each shape can be precisely machined. However, the mechanical processing consumables are expensive, and the cost is high. "Tiangong" has not yet been machined. However, the principles are the same. All of them need fine tools and reasonable machining tools to form a device.
Therefore, the synthesis of 3-2-1, its use, quantity, cost and other factors, and a method or method can be combined to form a combined device.

Mercury is feminine and heavy in nature. It is liquid at room temperature, like water and dignified, with a shimmering silver light. Its quality is smooth and greasy, its flow is irregular, and it is attached to objects and difficult to hold.
Mercury is toxic, which is its important characteristic. Its poison is hidden and quietly harmful. If a person accidentally touches it, smells it, or eats it, it will be poisoned into the body, and at first or not, for a long time, the viscera will be damaged, and the qi and blood will be disordered. In light cases, it will be dizzy, nausea, and body fatigue. In severe cases, it will be confused and endanger life.
Furthermore, the chemical activity of mercury is lively. Although the normal state is quiet, it often changes when encountering other things. It can bond with many metals, forming a state of amalgam, like a fusion, and its properties are very different from before. This characteristic makes it very popular in ancient alchemy and pill refining.
The volatility of mercury should not be underestimated. In the open, it gradually turns into mercury vapor, which disperses in the air. Its gas is invisible and colorless, but it contains highly toxic, quietly entering the breath, accumulating more and more, causing great harm.
Mercury also has good thermal and electrical conductivity. Although it is a liquid, it has good thermal and electrical conductivity, which is also applied to today's technology. However, although the ancients did not understand this principle, in practice, due to the various characteristics of mercury, it was either used for alchemy to seek longevity or for technological production, and the toxicity of mercury was often a problem. Therefore, it was necessary to know its nature and make good use of it, avoiding its harm and seeking its benefits.

When forging swords, many matters need to be carefully paid attention to during storage and transportation.
The storage place must be selected in a dry and ventilated place. If it is in a humid place, the sword body is prone to rust, damaging its sharpness and texture. In the past, there were good materials for forging swords, which were hidden in a damp warehouse, and soon rust appeared. When the sword was used, its quality had changed, and it was difficult to become a divine weapon. And the storage place should be protected from fireworks. The material of the sword is more flammable. If it encounters an open fire, disaster may occur. In the past, the swordsmiths lost their materials due to fire, and years of hard work were destroyed in one fell swoop.
Furthermore, the required protection against rodents and insects for storage. Rats have sharp teeth, which can damage the scabbard, and insects and ants may also eat the accessories of the sword body, causing damage. When keeping it, you should also check it regularly to see if there is any rust or damage. If there is any abnormality, you should deal with it in time.
As for transportation, you need to choose a sturdy instrument to load. The blade of the sword is sharp, and if you don't pay attention, it will cut the package and endanger the person handling it. Therefore, it needs to be wrapped in a thick cloth or a special sword cover, and then placed in a wooden box. The box is filled with soft objects to prevent bumps and collisions. In the past, there were swordsmen who transported swords, but they only wrapped them in thin cloth. On the way, the blade cut the package and almost hurt people.
Handlers also need to be specially trained to know the characteristics and handling skills of swords. When handling, the movements should be steady and light, and must not be treated rudely. If you are walking on mountain roads, you should be extra careful to prevent damage to the sword due to rough roads. And during transportation, pay attention to weather changes. In case of rain, you need to cover it in time, and do not let the sword be drenched by rain, so as not to affect the quality.

The price of goods varies from time to time, and it also varies with the thickness and quality of the goods. As for the market value range of three feet of silk and two feet of silk, let me analyze it in detail for you.
The price of silk depends first on the material. If the strands are fine, the weaving is exquisite, the color is fresh and will not fade for a long time, the texture is flexible and not easy to break, this is the best product, and its price is high. On the contrary, if the silk is rough, the weaving method is poor, the color is dark and easy to fail, and the quality is brittle and easy to break, the price will be low.
Furthermore, the supply and demand of the city is also the key. When the demand for silk is abundant, but there are few producers, and everyone is competing for it, its price is bound to rise; if the demand for silk is too high, the goods are accumulated in the market, and the merchants want to sell it quickly, the price will decline.
Also worth the age of the year, sorry, the distance between the regions is near and far. The people are rich in rich years, and the purchasing power is strong. Although silk is expensive, there are buyers; the poor in old age, the livelihood is difficult, and although it is cheap, it is difficult to buy it. And when the goods from distant places are transshipped to the city, the cost will increase, and the price will also increase.
According to common sense, the best three feet of silk, in the bustling city, may be worth five to eight taels of silver; the middle, about three taels to five taels; the lower, one tael to three taels. As for two feet of silk, the upper, or worth three taels to five taels of silver; the middle, one, two, five to three taels; the lower, half taels to one, two, five taels. However, this is only a rough number. The market conditions are ever-changing, and it is difficult to determine with certainty. Only those who have insight into the current situation can know the price and make a profit.