2 Iodopyridine

The second important thing is to study the relationship between heaven and man, through ancient and modern times, and become a family. This is the gist of historians' history, and it is also the key to those who seek the Tao.
"Heavenly Works and Objects", which gathers hundreds of technical skills, describes the general method of creation, and does not study mulberry, smelting, ceramics, boats, etc. Its intention lies in the principle of the generation of things. The things under the world are all created by heaven and earth, and people use wisdom and ingenuity to tailor and utilize them. Such as the cultivation and sowing of things, because they are suitable for local conditions, they can only obtain five times. The ratio of smelting, and the proportion of gold, and mastering the heat, is a good tool. Song Zi wrote this book, wanting people to be at ease with the nature of things and the suitability of things, so as to conform to the order of heaven's work and nature.
The second is to inherit the technology in the world. In ancient times, the same technology was made to improve people's livelihood. However, the moon is changed, and the technology may be lost. "Tiangong And "Heavenly Works and Objects" is based on the original text, and all the instructions are,. Teach people to step on the heart, research skills, and use the hands of diligence to create things. If this is done in the world, it will make people's hearts and people's hearts, and it will be prosperous.
, the weight of "Heavenly Works and Objects" has made great contributions to the world's scientific and technological development and cultural development.

There are many ways to combine mortise and tenon, each showing its own wonders. It can be seen in the book "Tiangong Kaiwu".
It has a dovetail, shaped like a dovetail, and the mortise and mortise are in this shape. Applied to cabinet drawers, boxes, etc., it is tightly fastened, can bear heavy objects, and is not easy to disengage. If a small box is made, the wall of the box and the bottom of the box are connected with a dovetail, which is tightly sewn, which can ensure the firmness of the box and the stability of the object.
There are also rice dumplings and tenons, which are combined in three ways, and the corners and corners are interlocked, just like the corners of zongzi. It is more common in the corners of tables and cabinets. This tenon method needs to be well measured and skillfully carved, so that the three square materials can be closely connected to form a stable structure. If a wooden table is made, the legs of the table and the border of the table are connected with dumplings and tenons, which not only have a beautiful state, but also have a stable quality, and the support is not tilted.
There are also lattice tenons, which are often seen in frame production. The edge of the wood is cut into a 45-degree angle, and then spliced into a frame, and the corners are mostly supplemented by tenons and tenons. Such as the frame of doors and windows, with lattice tenons, the lines are smooth, the appearance is regular, and it is both practical and beautiful. Fine cutting is required during production to make the corners fit, so that the good structure can be achieved.
Furthermore, shoulder tenons are also commonly used. Used for waist-bound furniture, such as waist-bound tables. The upper part of the legs and feet is cut out of the oblique shoulder, which is hugged with the groove of the tooth plate, which is tightly combined and has strong support. When making a table with a waist, the legs and the tooth plate are connected with the shoulder tenon, which can make the table stable and not shake for a long time.
The above tenon-and-tenon method depends on the exquisite skills of the craftsman. Only with accurate measurement and delicate carving can the wood and wood be combined into a strong and exquisite tool, and the wisdom of the ancients can be passed on to future generations.

The physical properties of 2-% projectiles are: hard texture, mostly made of metal, so heavy weight. According to the common iron projectile theory, its density is large, and it feels heavy at the beginning. After firing, it can cause significant damage with strong kinetic energy. Its shape is usually a sphere, which is conducive to maintaining stable flight during launch, reducing the interference of air resistance on its trajectory, so that it can hit the target more accurately.
The surface of the projectile is relatively smooth, which also helps to reduce the friction with the air during flight, and the smooth surface can reduce the friction when moving in the gun or gun bore, making the firing process smoother and improving the firing efficiency and reliability.
Furthermore, the projectile has good compression resistance. At the moment of launch, it has to withstand the huge pressure generated by the gunpowder gas. If it does not have enough pressure resistance, it will deform during the launch process, resulting in launch failure or affecting the shooting accuracy. Because the projectile has this physical property, it can maintain its shape and structure intact under strong pressure, ensuring that it can fly at a high speed with a predetermined trajectory, and achieve the purpose of killing or destroying the target. Its hard texture can not only resist the pressure during launch, but also penetrate or destroy the target object with its own hardness when hitting the target, and play its due role.

2-% drug, its chemical properties are as follows:
The chemical properties of this drug are related to its utility and characteristics. It is stable, under normal temperature, it can maintain its own structure for a long time, and it is not easy to decompose and deteriorate due to ordinary environmental changes. Such stability allows the drug to maintain quality during storage and transportation, and will not easily fail.
And its solubility is also a key property. In a specific solvent, it can be moderately dissolved, or instant, or slow dissolution. This property determines the absorption and distribution of the drug in the body. If it dissolves well in body fluids, it is easy for the body to absorb, quickly reach the lesion, and exert curative effect.
Furthermore, its acidity and alkalinity have a great impact on the efficacy of the drug. The appropriate pH can not only ensure the stability of the drug in the body environment, but also help it to accurately bind to the target. Too acidic or alkaline may affect the activity of the drug or cause adverse reactions.
At the same time, this drug has a certain chemical reactivity. It can react with specific substances in the body or participate in the metabolic process to achieve therapeutic purposes. However, this reactivity needs to be precisely regulated. If it is too strong, it may cause excessive reactions and damage the body; if it is too weak, the drug effect will not meet expectations.
The chemical properties of drugs are complex and delicate, and each property is interrelated and affects each other. Stability, solubility, acidity, alkalinity, and reactivity together form the foundation for a drug to function. Only by deeply understanding and making rational use of these properties can a drug maximize its effectiveness in treating diseases and ensure the well-being of patients.

Storage and transportation are related to the national economy and people's livelihood, and many people should pay attention during this period.
In terms of storage, the first storage site should be selected. It is advisable to choose a place with high and dry terrain to prevent rain from soaking and causing the stored things to rot. And it is necessary to consider the surrounding environment, stay away from water and fire, and ensure the safety of storage. Like ancient warehouses, they are mostly built near city walls, which is convenient for protection and transportation. Furthermore, the stored things should be properly placed according to their characteristics. Grain and the like need to be ventilated and moisture-proof; cloth silk and linen should be avoided from moisture and insects. Regular inspection to check for mildew and insect-eaten signs. If so, take quick treatment to avoid loss.
As for transportation, the distance of the journey and the quality of the road conditions are all key. In case of mountains and rivers, it is necessary to plan carefully and choose convenient routes. If the waterway is feasible, we should make good use of the convenience of boats, which will be large and labor-saving. However, rivers often change in flood and dry, so we need to know when to take advantage of the situation. During flood season, flood control will be washed away, and during dry season, we will worry about shallows. Land transportation, the power of vehicles and horses cannot be ignored. The feeding of animal power and the repair of vehicles must be carefully. And security on the way is also a priority, preventing bandits from looting and protecting the smooth transportation.
And the transportation journey, the time is also exquisite. In hot summer and heat, it is not suitable to transport perishable products; in cold winter and twelfth lunar month, when to prevent objects from freezing and cracking. And those who transport it must choose those who are loyal and reliable, and entrust them with important responsibilities, so that they can ensure the safety of storage and transportation, so that things can flow smoothly, people can use them, and the economy of the country is prosperous.