4-bromopyridine

4 - The main use of the image is to observe the passage of the sky and show the transformation of the celestial phenomena, so as to help the ancients to understand the sky and understand the will of the sky.
The image is a delicate system of ancient astronomical instruments. Its shape is like the celestial sphere, which is modelled on the image of the sky. Among them, the primary use of the image is to be able to directly show the distribution of the stars in the sky. Ancient astronomical scholars can understand the position and arrangement of the stars, as if the sky is in control. For example, the astronomical exploration of the era of "Heavenly Works", the image is an indispensable weapon.
Furthermore, the image can show the action of the sky. The sun, moon and stars alternate between night and night, and the four changes, and their behavior has a law. By means of ingenious mechanical arrangements, the image of the sky can be mimicked, so that the person can see the sky and make clear the passage of time. This is especially important for the farming community. It helps people to work according to the sky, and it refers to the work of the people.
And the image can show the picture of the sky. The ancients believed that the celestial phenomenon and the human relationship, the star, the coma, etc., are all shown by the sky. The image can be made into the celestial manifestation, for the occupiers, the rulers, etc., to promote good luck and good luck, and to help people's livelihood.
As the crystal of ancient astronomical wisdom, with its functions of modeling celestial phenomena, developing celestial movements, and revealing celestial phenomena, it played an important role in many fields such as ancient astronomy, technology, politics, and culture. It was an important medium for the ancients to explore the sky and connect the world.

The methods of synthesis of 4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4 The required chemical products, according to a specific ratio, are put into a refined container. First, add the amount of oil to the degree of sum, so that the products can be fused with each other and reversed. In reverse, it is necessary to mix them without mixing, so that they are homogeneous. It is necessary to check the quality of the product. If it is normal, the degree of straightening or the proportion of the product should be immediately adjusted. When the reverse is completed, the cold container should be filled with a mixed liquid containing 4-10. Then the method of division and extraction can be obtained.
Third, the method of biological extraction can also be feasible. There are strange organisms in the world, and they can be stored. Capture this organism and immerse it in the solution of the mixture to dissolve the organism. The leaching liquid is easy to obtain, but the process is cumbersome and energy-consuming; the chemical synthesis method can precisely control the composition, but the products used may be dangerous and costly; the biological extraction method can ensure that the biological sources are limited and the extraction efficiency is large. To obtain the 4-dimensional solution, it depends on the needs, sources and components.

4-Cyanopyridine is an organic compound with many unique physical properties.
Its appearance is white to light yellow crystalline powder, which is easy to store and transport, and is also easy to use during many chemical reactions. Under normal temperature and pressure, 4-cyanopyridine is quite stable. This stability provides convenience for its storage and use in various environments, and will not easily decompose or deteriorate due to minor changes in the external environment.
When it comes to solubility, 4-cyanopyridine is soluble in a variety of common organic solvents, such as ethanol, acetone, chloroform, etc. In ethanol, it can interact with ethanol molecules by means of intermolecular forces to achieve uniform dispersion and dissolution. This solubility makes it widely used in the field of organic synthesis. Chemists can dissolve it with suitable organic solvents to participate in various reactions and greatly expand the feasibility and diversity of reactions. However, the solubility of 4-cyanopyridine in water is relatively low, which is due to the existence of cyano and pyridine rings in its molecular structure, which makes it difficult to form effective interactions with water molecules, limiting its solubility in water.
The melting point of 4-cyanopyridine is within a certain range, about 105-107 ° C. The melting point is of great significance in the identification and purification of substances. By measuring the melting point of the unknown sample and comparing it with the standard melting point of 4-cyanopyridine, it can be preliminarily determined whether the sample is this substance. In the purification process, the use of melting point differences, recrystallization and other means can effectively separate impurities to obtain high-purity 4-cyanopyridine. Its boiling point is also a specific value, about 212-213 ° C. The boiling point characteristics are related to its application in separation operations such as distillation, and the appropriate temperature conditions can be selected to achieve separation from other substances.
4-cyanopyridine has a certain odor. Although it is not extremely strong and pungent, it also has a unique smell. This smell needs to be paid attention to when handling the substance, because it may suggest the volatilization or leakage of the substance, which can be used as a simple and intuitive warning signal to remind the operator to pay attention to safety and standard operation.

Borax is cold in nature and salty in taste. Its chemical properties are specific, and there are many wonders.
Borax can be dissociated in water and is in an alkaline state. When it encounters acid, it can react to form boric acid. Boric acid is also unique in nature and can be used for anti-corrosion and other things. When borax meets metal ions, it can often form a complex. The properties of this complex, which may be different from the original substance, are useful in many fields.
And borax has buffering properties. In solution, it can stabilize its pH and prevent it from changing significantly. In the industrial field, borax is often used as a flux. Because it can reduce the melting point of metals and help them melt, making metallurgy more smooth. In the industry of enamel and glass, borax is also indispensable, which can increase its luster, strengthen its strength, and make it more durable and beautiful.
In the process of medicine, borax is also effective. In the past, it was often used as a disinfectant and preservative to clean wounds, prevent them from decaying, and help wounds heal. In the folk, some people also use borax in food, but now it is known that its excess is harmful and cannot be abused.
In addition, borax can be used as a mordant in the printing and dyeing industry. It can make dyes easier to adhere to fabrics, and the color is more vivid and lasting. In the art of alchemy, the ancients also used borax. Although its cognition may be limited, it can be seen that the use of borax has a long history, and it shows its unique chemical properties and functions in many aspects.

The system of the boat is related to storage and transportation, so everyone should pay attention.
When storing, the first warehouse is sturdy. If the warehouse is not solid, it is easy to leak in case of wind and rain, and it is easy to be damaged in case of water and fire, and the grain is damaged by it, which will cause loss. Therefore, when building a warehouse, it is necessary to choose a high-pitched place to avoid water hazards; its materials should be sturdy, and the masonry and wooden beams should be durable. And the warehouse should be equipped with moisture barriers to prevent the earth and air from invading and causing the grain to rot. It also needs ventilation holes to circulate the air, remove moisture and dissipate heat, and keep the grain dry.
Furthermore, the number of stored grain should be counted in detail. It is not advisable to live within the limits of one's income, so that the warehouse will be full of trouble; nor should it be neglected, so that there will be a lack of emergency. The person in charge of the warehouse must be careful in bookkeeping, clearly check the number of incoming and outgoing, and check it on time to prevent the invasion of silverfish and insects, and the consumption of rats and sparrows.
As for the time of water transportation, the repair of the boat is extremely important. The body of the boat is easy to wear and tear after traveling in rivers over the years. If its boards are rotten, it will be easier if they are not rotten in time, and it will be dangerous in case of storms. The mast, cable, etc. also need to be inspected from time to time. The stability of the mast is related to the hanging of the sail, which can help the power of the boat; the firmness of the cable is indispensable for the berthing and towing of the ship.
< b Know the depth of the waterway, observe the speed of the current, and avoid the dangerous beaches of the reef. Boats need to be experienced and able to judge the situation. In case of downwind, you will set sail and move forward while the tide rises; if you are against the wind and tide, you should seek shelter from the wind, wait patiently for the opportunity, and do not force it.
And the safety of the water transportation cannot be ignored. To prevent thieves from robbing, you need to set up guards and patrol day and night. And to prevent traitors from corruptive practices. The transporters must be fair and honest, and must not swallow the grain or cut corners on the boat.
All these are matters that should be paid attention to in the storage and transportation of the water transportation. It is related to the storage of the country and the livelihood of the people.