CATDOLL : CATDOLL: What are the commonly used fish oxytocins?

1. What are the commonly used fish oxytocins?

Commonly used fish oxytocin agents include the following: 1. Oxygen: Oxygen is a hormone-based oxytocin agent, which is often used to increase the spawning rate of female fish and promote the maturation of follicles. Common oxytocin agents include synthetic GnRH (growth hormone-releasing hormone), hCG (human chorionic gonadotropin), etc. 2. Clonidine: Clonidine is an anesthetic, which is often used in the process of fish oxytocin. It can inhibit the physiological response of fish, reduce the stress response during spawning, and increase the spawning rate. 3. Ovaprim: Ovaprim is a commercial oxytocin agent made of a mixture of GnRH and hCG. It is often used in artificial breeding of marine fish and can effectively promote follicle maturation and spawning. 4. Acacetin: Acacetin is a plant extract with an oxytocin effect. It is often used in artificial breeding of freshwater fish and can increase the spawning rate of female fish and promote the maturation of follicles. It should be noted that the use of fish oxytocin agents should comply with relevant laws, regulations and technical specifications to avoid adverse effects on the environment and fish. At the same time, the use of oxytocin requires strict adherence to the instructions to ensure the effectiveness of oxytocin and the health and safety of the fish.

2. Reasonable use of fish oxytocin?

The drugs currently used to induce spawning using dried fish include: the commonly used fish ovulation induction No. 2 (LHRH-A2), fish chorionic gonadotropin (polysexual hormone, HCG), chorionic gonadotropin type A, chorionic gonadotropin type B, fish ovulation induction No. 3 (LHRH-A3), diometron (DOM), fish pituitary gland (pituitary gland, PG) and a variety of complex high-efficiency oxytocin, but the most commonly used ones are fish ovulation induction No. 2 (LHRH-A2) and fish chorionic gonadotropin (polysexual hormone, HCG).

For fish with low spawning rate and low total spawning volume, such as loach, Chinese spiny target (Qingbo) and other medium and high-end fish, dioic acid (DOM) and pituitary gland (PG) should be added on the basis of using LHRH-A2+HCG, and the effect will be doubled.

For common fish, such as grass carp, silver carp, bighead carp, carp, crucian carp, etc., LHRH-A2+HCG is effective, and there is no need to add other oxytocin drugs to reduce production costs. Grass carp using LHRH-A2 alone, silver carp using chorionic gonadotropin type A alone, and bighead carp using chorionic gonadotropin type B alone are sufficient to achieve the purpose of smooth spawning. Also refer to: Rational use of fish oxytocin

3. What is the basic principle of fish oxytocin?

The principle is to use a combination of physiological and ecological methods to directly inject oxytocin (PG, HCG or LRH-A, etc.) into the fish, replacing the effect of the gonadotropin secreted by the fish's own pituitary gland, or replacing the effect of the hypothalamus releasing LRH, which triggers the pituitary gland to secrete gonadotropin, thereby promoting oocyte maturation and spawning. Among fish oxytocin, the main components of the pituitary gland and HCG are FSH and LH. After entering the blood circulation of fish, they directly act on the gonads of carp, promoting gonadal maturation and spawning;

4. What are the commonly used lubricants and lubrication methods for punching machines?

There are two types of commonly used lubricants, one is butter

The other is hydraulic oil.

There are several ways of lubrication: some use manual refueling, some use electric refueling, and some use oil pump circulation lubrication and refueling. It depends on the model.

1. Manual oiling and lubrication. The operator manually adds lubricating oil or grease to the friction parts, which are used for friction pairs with light load, low speed or intermittent operation. Such as guide rails, pulleys and roller chains (oil injection lubrication), toothed chains (oil brushing lubrication), rolling bearings and ball screw pairs (grease lubrication) of ordinary machine tools.

2. Oil dripping lubrication. The lubricating oil drips into the friction parts by its own weight (usually using a needle valve dripping oil cup). It is used for friction pairs that are small in number and easy to access, such as rolling bearings that require quantitative oil supply, unimportant sliding bearings (circumferential speed less than 4-5m/s, light load), chains, ball screw pairs, and plate friction clutches with a circumferential speed less than 5m/s.

3. Oil wick lubrication. It uses the capillary action of the oil wick immersed in oil or the negative pressure formed by the rotating shaft for self-priming lubrication. It is used for medium and low-speed gears, sliding bearings that do not require much oil, medium-speed and light-load rolling bearings installed on vertical shafts, etc.

4. Oil pad lubrication: It uses the capillary action of the oil pad immersed in oil for lubrication, and is used for sliding bearings with a circumferential speed of less than 4m/s.

5. Self-priming lubrication. Self-priming lubrication is performed using the negative pressure formed by the rotating shaft. It is used for precision machine tool spindle sliding bearings with a circumferential speed greater than 3m/s and a bearing interval less than 0.01mm.

6. Centrifugal lubrication: Under the action of centrifugal force, the lubricating oil flows continuously along the conical surface to the lubrication point, which is used for rolling bearings installed on vertical shafts.

7. Oil bath lubrication. Part or all of the friction surface is immersed in lubricating oil for operation. It is used for medium and low speed friction pairs, such as closed gears with a circumferential speed of less than 12-14m/s; worms, chains, rolling bearings with a circumferential speed of less than 10m/s; sliding bearings with a circumferential speed of less than 12-14m/s; plate friction clutches with a circumferential speed of less than 2m/s, etc.

8. Oil ring lubrication: The rotating parts pass through the oil pool, bringing or splashing the oil to the lubrication parts. It is used for sliding bearings with stable load and speed of 100-2000r/min.

9. Splash lubrication. The rotating parts pass through the oil pool to bring or splash the oil to the lubrication parts. It is used for enclosed gears, rolling bearings that are easily splashed with oil, high-speed sliding bearings, roller chains, plate friction clutches, etc.

10. Scraper lubrication: The rotating parts pass through the oil pool, bringing or splashing the oil to the lubrication parts, which is used for low-speed (30r/min) sliding bearings.

5. What is the order of strength of commonly used oxidizing and reducing agents in high school chemistry?

Commonly used methods for judging the strength of oxidizing and reducing properties

① Judging by the activity of the metal

a. The stronger the metallic property of a metal, the stronger the reducing property of the element, and the weaker the oxidizing property of its corresponding ion.

b. Reducibility of elements: It decreases in the order of metal activity.

c. Oxidizing property of ions: increases in the order of metal activity.

For example: anion > mercury ion > iron ion > copper ion > hydrogen ion > ferrous ion.

② Judging by the activity of non-metals, the stronger the non-metallic property, the stronger the oxidizing property of the element, and the weaker the reducing property of its corresponding ions.

For example: oxidizing fluorine gas > chlorine gas > bromine gas > iodine > sulfur; reducing sulfide ion > iodine ion > bromide ion > chloride ion > fluoride ion

③Judge based on the direction of the redox reaction and the reaction conditions or intensity

a. Oxidizing property: oxidant > oxidation product.

b. Reducibility: reducing agent > reduction product.

c. When different oxidants (reducing agents) react with the same reducing agent (oxidizing agent), the easier the reaction conditions, the stronger the oxidizing (reducing) property.

For example, according to the reaction conditions of concentrated hydrochloric acid with potassium permanganate, manganese dioxide, and oxygen, respectively, at room temperature, heating, and catalyst and heating, the order of oxidizing power of the oxidants can be judged as potassium permanganate>manganese dioxide>oxygen.

d. When different oxidants (reducing agents) react with the same reducing agent (oxidizing agent), the more violent the reaction, the stronger the oxidizing (reducing) property.

For example, when sodium and potassium react with water separately, potassium reacts more violently, so the reducing power is: K> Na

④ Judge based on the electrode reaction of the primary battery or electrolytic cell

a. Two different metals constitute the two poles of the primary battery. The negative metal is the pole where electrons flow out, and the positive metal is the pole where electrons flow in. Their reducing properties are: negative pole > positive pole.

b. When an inert electrode is used to electrolyze a mixed solution, the cations that are discharged first at the cathode have stronger oxidizing properties, while the anions that are discharged first at the anode have stronger reducing properties.

⑤ The oxidizability or reducibility of certain substances is related to external conditions

a. Temperature: For example, concentrated sulfuric acid has strong oxidizing properties, and hot concentrated sulfuric acid is more oxidizing than cold concentrated sulfuric acid.

b. Concentration: For example, the higher the concentration of nitric acid, the stronger its oxidizing power.

c. Acidity and alkalinity: For example, the oxidizing property of potassium permanganate 4 increases with the increase of acidity.

The order of oxidizing and reducing properties commonly used in high schools is: Oxidizing power: sulfur < iodine < iron ion < bromine < chlorine < manganese dioxide

Reducing ability: Sulfur ion > Sulfur dioxide > Iodide ion > Ferrous ion > Bromide ion > Chloride ion > Divalent manganese ion

6. What is the specific order of strength of commonly used oxidizing agents and reducing agents in high school chemistry?

1. Oxidant:

1. Typical non-metallic elements such as F2, Cl2, O2, Br2, I2, S, Si, etc. (the strength of their oxidizing properties is basically consistent with the activity of non-metals).

2. High-valent compounds containing variable-valent elements, such as KMnO4, KClO3, concentrated H2SO4, HNO3, MnO2, FeCl3, etc.

3. Metal cations such as Fe3+, Cu2+, etc.

2. Reducing agent:

1. Active metal elements: such as Na, Al, Zn, Fe, etc.

2. Certain non-metallic elements: such as H2, C, Si and other elements (such as C, S, etc.).

3. Alkali metal elements: such as Li, Na, K, etc.

4. Oxides at low valence: such as CO, SO2, etc.

5. Non-metal hydrides: such as H2S, NH3, HCl, CH4, etc.

6. Salts in low valence state: such as Na2SO3, FeSO4, etc.

7. What are the emulsifiers commonly used in baked goods and what are their respective characteristics?

There are two parts in the emulsifier molecule: hydrophilic and lipophilic. According to the characteristics of their hydrophilic parts, they can be divided into the following categories:

①Anionic emulsifier.

It is an emulsifier that ionizes in water to generate negative ionic hydrophilic groups with alkyl or aromatic groups, such as carboxylates, sulfates and sulfonates.

This type of emulsifier is the most commonly used, and common products include: soap, sodium stearate, and ten.

8. What is the usual amount of diesel octanol flocculant used in coal washing plants, based on tons of raw coal?

Medium powder: 1.5--2.0kg Diesel + 2-octanol: 0.20kg Flocculant: 20g

9. What are the types of compressors and refrigerants commonly used in household air conditioners, car air conditioners and refrigerators?

The current mainstream household air-conditioning compressor is a rotary compressor, and the refrigerant (coolant) is R22.