"Tiangong Kaiwu" contains, Jiangsu and Zhejiang silkworm species, which have come for a long time, and are mainly produced in Huzhou. Silkworm species are crucial to silkworm breeding, and are related to the quality and quantity of silkworm cocoons. Its main uses are as follows:
First, it is related to the reproduction of silkworms. High-quality silkworm species have good genetics, which can ensure the stability of silkworm populations during the growth process. Such as silkworm body size and development cycle, which can be relatively consistent, which is convenient for silkworm farming management and production arrangements. And good genetic characteristics can make silkworms have strong vitality and high resistance to diseases, reduce the probability of silkworm disease outbreaks during breeding, and improve the overall survival rate of silkworm populations.
Second, affect the quality of cocoon silk. The cocoon silk produced by different silkworm species has obvious differences in quality. Huzhou silkworm species can produce cocoons with excellent silk quality. Its silk is long and thin, with good toughness and white color. With this kind of silkworm cocoon reeling silk, the finished product has fine texture and good gloss. It is favored in the market and can obtain higher economic value. Like the silk used in ancient royal families, cocoons produced by high-quality silkworm seeds are mostly used as raw materials.
Third, it determines the breeding efficiency. Excellent silkworm seeds grow rapidly, eat mulberry efficiently, and can reach the mature silk spinning stage in a relatively short time. This not only saves breeding time and costs, but also increases the number of sericulture batches in one year, improves the utilization rate of land and equipment, and brings more benefits to sericulturists. Therefore, silkworm farmers pay attention to the selection of silkworm seeds to obtain the best breeding benefits.
In short, Jiangsu and Zhejiang silkworm species, especially Huzhou silkworm species, play a key role in silkworm production, from reproduction, cocoon quality to breeding benefits, all-round impact on the entire sericulture industry.

The physical properties of the 4-Jiang-2-River mussel shell are as follows:
Its texture is hard and has a certain toughness. The shell appearance is mostly oval or fan-shaped, with unique lines. These lines are like traces left by the years, or clear or obscure, or regular or complicated, which are the result of the environment and time of the mussel during the growth process.
The surface of the shell usually has a layer of luster, like a layer of gauze-like halo, which varies depending on the type of mussel, the growth environment and the preservation condition. Some shells are shiny and radiant, emitting a soft light like a pearl; others are relatively dull.
In terms of weight, it varies depending on the size and thickness of the shell. Generally, small mussel shells are lighter and feel lighter in hand; large mussel shells are relatively heavy, and their weight can be clearly felt in the hand.
Shells are rich and diverse in color, commonly gray-white, just like the mist in the early morning of winter, elegant and pure; there are also tan, like the color of the earth, calm and heavy; some shells also have colorful colors, such as rainbows falling on them, which are dazzling, mostly due to the influence of minerals and other factors in the environment.
Shells have high hardness and can withstand a certain degree of external impact, but their edges are relatively thin and brittle, and are prone to damage and fracture if they are hit by sharp objects or bent by large external forces. The internal surface of the clam is relatively smooth, and it feels delicate when touched. This is because during the long-term growth process of the clam, the secretions continue to polish the interior.

The river is the one with the largest flow of water; the river is the one with the connection of waterways. The river passes through, and all things are born. Today's talk 4-river-2 riverbed foundation gravel, this is the thing hidden under the river. Its chemical properties are related to the ecology of rivers and rivers, and it is also a matter of water conservancy, which cannot be ignored.
The riverbed foundation gravel is mostly stony, and the stable chemical properties are mostly silicates. Such substances, resistant to water erosion, have passed through the years at the bottom of the river, and are not hydrodynamic. Looking at its function with water, although water is soft, it initialized for a long time, and there are subtle changes. Water contains various ions, such as calcium, magnesium, iron, etc., which interact with the surface of the base gravel, or have ion exchange. If the base gravel contains metal minerals, or under the action of oxygen and carbon dioxide in the water, there is a slow oxidation and carbonation change.
The place where the base gravel is located, if it is near a mine, may be contaminated with heavy metals. Heavy metals, such as lead, mercury, and cadmium, have different chemical activities. Lead is more likely to react with acids. If the acidity in water is slightly stronger, lead ions or dissolution. Mercury is volatile in the air, but it is in the riverbed base gravel, or combined with sulfur and other elements to form stable compounds. When cadmium encounters strong acid, it can also dissolve ions, and its ions can migrate in water, affecting aquatic organisms.
Furthermore, in the land passed by the river, if the soil is different in acidity and alkalinity, it also affects the chemical properties of the base gravel. If it is a river in an acidic soil area, the concentration of hydrogen ions in the water is high, and it reacts with the base gravel to accelerate the dissolution of soluble substances in the base gravel. On the contrary, in the alkaline soil area, there are many hydroxide ions in the water, or they combine with some metal ions in the base gravel and precipitate on the surface of the base gravel or the bottom of the water.
In summary, the chemical properties of the 4-River-2 riverbed gravel are influenced by many factors such as water composition, surrounding geology, soil acidity and alkalinity. Although the change is slight, it has a profound impact on river ecology and water conservancy projects.

The synthesis method of 4-ene-2-propargylamino is involved in "Tiangong Kaiwu", which is obtained by many experts in the field of chemical industry.
First, it can be started from the substrate containing alkenyl and alkynyl groups, and the method of nucleophilic substitution. Select suitable halogenated alkenes and propargylamines, use appropriate bases as acid binding agents, and control the appropriate temperature and time in organic solvents. If potassium carbonate is used as a base and acetonitrile is used as a solvent, heat and stir, the halogen atom of halogenated alkenes is replaced by the amino nucleophilic of propargylamines. This process needs to pay attention to the precise regulation of the proportion of substrates and reaction conditions to avoid the growth of side reactions and affect the purity and yield of the product.
Second, the coupling reaction catalyzed by transition metals. Select alkenyl borate or alkenyl halide with propargyl halide or the like, and use transition metals such as palladium and copper as catalysts, assisted by ligands, and react in the presence of bases. For example, palladium catalysts, bipyridine ligands, and cesium carbonate are used as bases in toluene solvents to form carbon-nitrogen bonds catalyzed by metals to achieve the construction of 4-alkenyl-2-propargylamino groups. This approach is crucial for the screening of catalysts and ligands, which has a significant impact on reaction activity and selectivity.
Third, through a multi-step reaction strategy. The alkenyl-containing structure is constructed first, and then the propargyl amino group is introduced. For example, the alkenyl intermediate is formed by allylation reaction first, and then the propargyl amino group is introduced by nucleophilic addition or substitution. Although this strategy has many steps, the reaction of each step can be fine-tuned according to needs to improve the quality and yield of the product.
There are various methods for synthesizing 4-ene-2-propargyl amino groups. The practical application needs to be based on the availability of substrates, the feasibility of reaction conditions, the requirements of product purity and yield, and the best synthesis path should be selected.

4 - Jiang - 2 - When storing and transporting mussel pearl shellfish, pay attention to the following numbers:
First, when storing, choose a cool and well-ventilated place. These two can make the ambient temperature suitable and prevent it from spoiling due to high temperature. If it is in a hot place, the shellfish are prone to qualitative changes and damage their quality. Good ventilation can keep the air smooth, disperse moisture, and prevent the shellfish from being immersed in a humid atmosphere, so as to prolong their storage period.
Second, it is also crucial for the control of humidity. If the humidity is too high, the shellfish are easy to breed mold and cause it to deteriorate; if the humidity is too low, it is afraid of dehydration and affect the quality. Therefore, when maintaining a moderate humidity, it can be covered with a damp cloth or placed in a medium method of shallow water to keep it moisturized but not too wet.
Third, the packaging must be firm during transportation. Use soft cushions, such as hay, soft cloth, etc., to cushion vibration and prevent shellfish from being damaged in bumps. And the loading should not be too dense, leaving some space, so that the shellfish can breathe smoothly and facilitate air circulation.
Fourth, the transportation time should be reduced as much as possible. Shellfish need specific conditions to survive. If it takes too long, the living environment will gradually deteriorate, and it is easy to cause death. Therefore, it is necessary to plan a reasonable route and choose a fast transportation method to reach the destination quickly.
Fifth, temperature regulation runs through the whole process of storage and transportation. Sudden temperature changes have a great impact on shellfish. It is advisable to cool down in summer, such as using ice packs; it is advisable to keep warm in winter, and can be wrapped in quilts and other materials to keep the ambient temperature relatively stable to ensure the quality and activity of 4-Jiang-2-River mussel pearl shells.