For the human body, water is the most important substance, accounting for about 70% of human body weight, and is known as the "source of life". Many chemical reactions in the human body can only be carried out in the presence of water.
The inflow and outflow of water in normal body are equal: the thirst center of diencephalon regulates the inflow of water, and water enters the body through various foods eaten by human body and direct drinking. Among them, drinking water directly is the most important way. The water evaporated and breathed from the body surface in 24 hours at room temperature is about 800 ml, and the urine output of the kidney every 24 hours is about 1~2 ml. Generally speaking, a healthy adult needs about 2500 ml of water day and night. However, in the case of rising temperature, falling temperature or strenuous exercise and sweating, the human body will also lose a lot of water, so the water needed by the human body is not constant and inconvenient.
In our daily life, the main types of drinking water are boiled water from tap water and directly drinkable water sold in the market, such as pure water, mineral water and distilled water. Nowadays, advertisements for all kinds of drinks and drinking water are overwhelming, flooding the streets. In today's increasingly serious water pollution, although these water commodities are expensive, they still attract many consumers and have the momentum to replace the traditional habit of drinking boiled water.
There is no doubt that drinks, high-quality mineral water and pure water are much more reassuring than tap water or well water, river water and lake water in rural areas. However, the debate also arises with the change of people's drinking style. We often hear or see experts' suggestions, and the conclusions are often contradictory. This requires us to think, analyze and make corresponding choices according to the specific situation.
In a big city like Shanghai, drinking pure water has been more and more accepted by people. The production process of pure water is generally: tap water passes through quartz sand filter, activated carbon filter, resin exchange device and reverse osmosis membrane device in turn under the action of pressure pump, and then passes through the filter for repeated circulation filtration. The filtered and purified water reaches the standard of drinking water, then it is disinfected with ozone, and then it is exported through pipes or bottles, which becomes the pure water we drink. In this process, the main function of quartz sand filtration is to further filter out the residual solid particles in tap water; Activated carbon plays the role of adsorbing organic matter in tap water; In the resin exchange device, firstly, inorganic salts in water are precipitated by flocculants, secondly, metal ions such as calcium, magnesium and aluminum are replaced by industrial salts, and wastewater is discharged. This method consumes four volumes of tap water to produce one volume of pure water. In the reverse osmosis membrane device, the water after the first three treatment processes is further filtered through the pipeline equipped with reverse osmosis membrane. Due to the special function of reverse osmosis membrane, the extremely fine particles of inorganic salts in water with a particle size of about 1/300 will also be filtered out, so that the water can reach the purity standard.
So is drinking pure water the most hygienic and beneficial to health? This is not necessarily the case! Because the general water contains all kinds of minerals and trace elements that are soluble in water, especially the most common elements such as calcium and magnesium, which are the elements that the human body must supplement frequently. Calcium is the main component of human bones and teeth, which plays an important role in maintaining the normal contraction of myocardium and promoting blood coagulation, so people need to constantly supplement calcium throughout their lives; Magnesium and other essential elements, each person needs to supplement about 0.3 ~ 0.5 grams of magnesium every day. Some of these two elements needed by human body are taken from drinking water. However, pure water is extremely soft water without calcium and magnesium ions, so people cannot be expected to absorb beneficial elements and supplement calcium and magnesium while drinking pure water. Moreover, the effect of any harmful substances in this soft water will be amplified, and a small amount of harmful substances in soft water will have greater harm and negative impact on our health than hard water of the same quality. So it can be said that drinking pure water is not very beneficial to health.
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Second, edible oil and human health
People need to eat oil, especially the growing teenagers. If you don't eat oil for a long time, it will lead to dry skin, desquamation, brittle hair and easy shedding, which will affect your physical development.
The oil we eat is vegetable oil and animal fat. Linoleic acid, linolenic acid and arachidonic acid contained in vegetable oils such as peanut oil, soybean oil, rapeseed oil, sunflower oil and sesame oil are all important unsaturated fatty acids necessary for human body. These organic acids cannot be synthesized in human body and can only be absorbed from edible oil. These unsaturated fatty acids have low melting point and easy absorption, and have the functions of lowering cholesterol and preventing atherosclerosis.
The chemical composition of animal fat is mainly saturated fatty acid glyceride. Each gram of fat can produce 9 kilocalories in human body, which is twice as much as the same mass of carbohydrates or protein. If animals eat too much fat, it will be transformed into adipose tissue and stored in the body, which will gradually make the body fat, increase the cholesterol in the blood and accelerate the hardening of the blood vessel wall, leading to hypertension, coronary heart disease and unexpected diseases such as heart, brain and kidney. Therefore, it is better for the elderly to eat vegetable oil. Children and teenagers' bodies are developing, moving more and consuming more energy. After the edible oil is digested and absorbed in the body, some provide energy for physical activities, while others form cell tissues. Oil contains cephalin, which is an indispensable nutrient for the normal growth and development of teenagers, so teenagers need vegetable oil and animal fat very much.
The edible method of oil is common in cooking. Cooking with oil is also very particular, otherwise it will be harmful to health. It seems that people are used to cooking after the oil smokes, but it is very harmful. Experiments have also proved that repeatedly heated used oil and oil residue will not only cause cancer if eaten, but also cause tumors if coated on animals or injected into muscles, because these substances contain carcinogens-polycyclic aromatic hydrocarbons.
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Three. Salt and human health
Salt is an important condiment in daily life. Salty taste is the most basic of three kinds of food: sour, sweet, bitter, spicy and salty. Without it, meals, soups and vegetables will become tasteless. Adding a proper amount of salt to meals, soups and vegetables can certainly make dishes fragrant and delicious and stimulate appetite, but more importantly, the human body cannot maintain normal physiological functions without salt.
Human blood contains about 0.6 ~ 0.9% salt. In this case, the heart can beat normally, and the muscles can keep stimulation sensitivity. When the human body loses a lot of water, it will be accompanied by a lot of salt loss. Doctors often treat it by subcutaneous or intravenous infusion of human physiological saline (sodium chloride aqueous solution). In the process of human metabolism, salt is often excreted with sweat. Workers engaged in high-temperature operations, or after intense physical labor and strenuous physical exercise, should pay attention to drinking some salted boiled water to supplement the salt content in their bodies. Lack of salt can make people dizzy, tired and weak, and reduce the efficiency of study and work. Long-term salt deficiency is prone to heart disease, and it will also produce "low sodium syndrome". So, is it better to eat more salt? No. If the human body consumes too much salt, it will affect the normal metabolism and make the acid-base balance unbalanced. Eating too much salt can easily lead to sodium retention, and long-term sodium retention can lead to kidney disease and hypertension. Modern medical research has proved that adhering to a light diet all the year round can make people live longer.
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Fourth, the multiple uses of salt.
The biggest use of salt is eating. In addition, salt is an important industrial raw material, which can be used to make soda ash, caustic soda, hydrochloric acid, PVC plastics and so on. Sodium metal can be produced by electrolyzing molten sodium chloride. In agriculture, salt solution is used to select seeds to ensure high germination rate, strong growth and high yield. In big cities, sanitation workers melt the snow on roads by spraying salt water to ensure the safety of vehicles and pedestrians. In the hospital, salt solution can be used instead of disinfectant to clean the wound, because the concentrated solution of salt can strongly absorb the water in the bacteria, which leads to metabolic disorder and death.
In daily life, salt has many uses. If you can use it skillfully, it will bring you a lot of convenience. For example, put some salt when washing clothes, and clothes are not easy to fade; When dyeing clothes, put some salt to make the color bright and firm; When cooking, put some salt in the pot, especially when frying fish, sprinkle some salt on the fish to prevent hot oil from spilling; In summer, sprinkling salt on fresh fish can prevent fish from spoilage; Getting up in the morning and drinking a cup of salty boiled water can clean the stomach and make the stool smooth; Frequent gargling with salt water can maintain oral hygiene and prevent diseases; Soaking melons and fruits in 15gb salt solution for 20 minutes can play a role in disinfection and sterilization; Boil broken eggs with salt water to prevent protein from flowing out; Adding some salt to the batter can prevent corruption and increase the viscosity of the batter.
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Five, the wonderful use of vinegar
Vinegar is a traditional acidic condiment in China, which was recorded as early as 2000 years ago. As the saying goes, "seven things to go out, rice, oil, salt, sauce, vinegar and tea." It can be seen that vinegar is one of indispensable foods for people.
Vinegar has a unique flavor and a wide variety in China. Some products are well-known at home and abroad, such as Zhenjiang balsamic vinegar, Shanxi mature vinegar and Fujian red kojic vinegar.
Vinegar is a good condiment. The taste is sour, slightly sweet and fragrant. Smell vinegar, taste vinegar, digestive juice is often naturally secreted, so it can stimulate appetite and help digestion, which is a good medicine for people with gastric acid deficiency.
Vinegar is made from grain, sugar or distiller's grains by acetic yeast fermentation. Ordinary vinegar contains 3 ~ 5% acetic acid. Besides the functions listed above, vinegar has many other wonderful uses.
Being jealous in summer and autumn can prevent intestinal infectious diseases.
Soaking fresh eggs in vinegar until they are dissolved can treat diseases such as hepatitis.
Soaking garlic in vinegar and eating it often can disinfect and prevent colds.
Treat onychomycosis with vinegar water.
The solution of vinegar and lime can remove the odor of body odor.
0.5 ~ 2% vinegar can be used to wash the wound infected by Pseudomonas aeruginosa.
Adding vinegar when cooking sweet porridge will make sweet porridge sweeter.
When stewing meat or ribs, put some vinegar to make it easy to cook.
Boiling pig's feet with vinegar can decompose the colloid in bone cells, which is convenient for pregnant women and children to absorb.
When the fish is not fresh, cooking with vinegar can not only remove the fishy smell, but also eliminate harmful bacteria.
Adding sugar to vinegar can relieve alcohol, because alcohol reacts with acetic acid to form esters.
When washing the fabric, put some vinegar in water to keep the original luster of the fabric.
Clothes are stained with juice spots or colors, which can be removed by rubbing with vinegar.
Woolen clothes will glow in some places when worn for a long time. You can spray them with a solution of vinegar and water, then put them on a wet cloth and iron them with an iron.
Polishing bronzes with vinegar.
It is easy to clean the dirt of aluminum products with vinegar water.
The wick of kerosene stove can be soaked in vinegar before use, which can reduce oil smoke.
Washing hot water bottles with vinegar can remove scale.
There are paint spots on the glass, so you can rub some vinegar on it and wipe it off easily.
Wrapping fish and meat with vinegar-soaked cloth can keep fresh fish and meat from going bad.
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Vitamins of intransitive verbs and human health
It is known that there are more than 20 kinds of vitamins, most of which cannot be synthesized in the human body and depend on food supply. The main vitamins are as follows.
(1) vitamin a: extracted from cod liver by American chemist Taves in 19 13. It is yellow powder, insoluble in water, soluble in organic solvents such as fat and oil. The chemical properties are relatively stable, but it is easily destroyed by ultraviolet rays, so it should be kept in a brown bottle. Vitamin A is the raw material of rhodopsin in eyes, and it is also an essential substance for skin tissue. Without it, people will get dry eye and night blindness. Usually everyone should take vitamin a 2 ~ 4.5 mg every day, not too many people. In recent years, related research shows that it also has anti-cancer effect. Animal liver contains a lot of vitamin A, followed by cream and eggs. Carrots, tomatoes and other vegetables contain a lot of carotene, which is the precursor of vitamin A and can be easily converted into vitamin A in the human body, so eating vegetables can also supplement vitamin A.
(2) Vitamin B: It is a water-soluble vitamin, and most of the human body is coenzyme, mainly including the following.
① Vitamin B 1:B 1 is the earliest purified vitamin. It was first discovered by Dutch scientist hickmann in 1896, and was extracted and purified from rice bran by Polish chemist funk in 19 10. White powder, easily soluble in water and easily decomposed in alkali. Its physiological function is to stimulate appetite and maintain normal nerve activity. Without it, it will cause beriberi and neurodermatitis. Adults need to take 2 milligrams a day. Widely found in rice bran, egg yolk, milk, tomatoes and other foods, has been artificially synthesized.
② Vitamin B2:B2 is also called riboflavin. It was first discovered by British chemist Bruce in 1879, extracted from milk by American chemist Goldberg in 1933 and synthesized by German chemist Cohen in 1935. Vitamin B2 is orange-yellow needle-like crystal, slightly bitter in taste, yellow-green fluorescence in aqueous solution, and easy to decompose under alkaline or light conditions This is why you don't need alkali to cook porridge. Without it, the human body is prone to stomatitis, dermatitis, microvascular hyperplasia and so on. Adults should take 2 ~ 4 mg daily, which is rich in cereals, vegetables, milk and fish.
③ Vitamin B6: 1930 was discovered by American chemist Kohler. Has the effects of inhibiting vomiting and promoting development. Without it, it will cause vomiting, cramps and other symptoms. Adults consume a large amount of 2mg every day, which is widely found in rice bran, soybean, egg yolk and animal liver, and has been artificially synthesized at present.
④ Vitamin B 12: 1947 was found in bovine liver extract by American female scientist Xiao Bo. According to the analysis of chemists, it is an organic compound containing cobalt. It has stable chemical properties and is an indispensable substance for human hematopoiesis. Lack of it will produce pernicious anemia. At present, it can be synthesized artificially, but the cost is high, so it is still made by biotechnology bacteria fermentation. The human body needs about 12 microgram every day, and people will not lack it under normal circumstances.
(3) Vitamin C: Vitamin C is also called ascorbic acid. Norwegian chemist holst found it in lemon juice on 1907. 1934 to obtain pure product, which can be synthesized artificially now. Colorless crystal, melting point 190 ~ 192℃, easily soluble in water. The aqueous solution is acidic, has strong chemical activity and is easily decomposed by heat, alkali and heavy metal ions. Therefore, copper pots are not allowed, and the heating time is too long. The main function of vitamin C is to help the human body complete the oxidation-reduction reaction and improve the sterilization and detoxification ability of the human body. Long-term lack of vitamin C will lead to scurvy, and adults need to take 50 ~ 100 mg every day. Eating more fruits and vegetables can meet the human body's demand for vitamin C. According to the research of Nobel Prize winner Pauling, taking large doses of vitamin C has a certain effect on preventing colds and fighting cancer.
(4) Vitamin D: 1926 Chemist Carl first extracted vitamin D from cod liver oil. It is light yellow crystal, melting point115 ~118℃, insoluble in water and soluble in organic solvents such as ether. Its chemical properties are stable, and it can still maintain its biological activity at 200℃, but it is easy to be destroyed by ultraviolet rays. Therefore, drugs containing vitamin D should be kept in brown bottles. The physiological function of vitamin D is to help the human body absorb phosphorus and calcium, which are necessary raw materials for bone construction, so the lack of vitamin D will lead to rickets. The human body should take 25 micrograms of vitamin D every day, but not too much, otherwise it will easily produce side effects. Rich in cod liver oil, animal liver and egg yolk. The synthesis of vitamin D in human body is related to sun exposure. Therefore, proper illumination is beneficial to health.
(5) Vitamin E: Vitamin E was discovered by American chemist Evans in 1922 and extracted from malt oil. It was synthesized artificially in the 1940s. 1960 China has been ready for mass production. It is odorless and tasteless liquid, insoluble in water and soluble in organic solvents such as ether. Its chemical properties are stable, heat-resistant, acid-resistant and alkali-resistant, but it is easy to be destroyed by ultraviolet rays, so it should be kept in a brown bottle. Vitamin E is an excellent antioxidant in human body. Without it, both men and women can't have children, and in severe cases, their muscles will atrophy and their nerves will be numb. In recent years, scientists have also found that it has anti-aging and anti-cancer effects. Vitamin E is widely found in meat, vegetables and vegetable oils. Under normal circumstances, there is no shortage of people.
(6) Vitamin K: Vitamin K was discovered and extracted from animal liver and hemp seed oil by Danish chemist Damme in 1929. Yellow crystal, melting point 52 ~ 54℃, insoluble in water, soluble in organic solvents such as ether. Vitamin K is stable in nature, resistant to heat and acid, but easily decomposed by alkali and ultraviolet rays. Can promote blood coagulation of human body. Without it, the clotting time will be prolonged, and in severe cases, people will bleed and even die. Strangely, there is a kind of bacteria in human intestine that can continuously produce vitamin K for human body, and it is rich in pig liver, eggs and vegetables, so most people will not lack it. At present, it has been artificially synthesized, and chemists can skillfully change its "properties" into water solubility, which is beneficial to human absorption and has been widely used in medical treatment.
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Seven, protect our water resources
Huangpu River and Suzhou River (formerly known as Wusong River) are two main rivers in Shanghai. At the beginning of the twentieth century, these two rivers were crystal clear and full of fish. In the 1990s, the "Kuroshio" of Huangpu River occurred frequently, and Suzhou River was like sewer water all the year round, black and smelly. It should be said that man-made pollution is the main reason for the great changes in Shanghai's mother river.
The pollution sources of Suzhou Creek can be divided into two categories, one is industrial pollution and the other is domestic pollution. Industrial pollution is an important source of pollution, but domestic pollution also has a considerable impact. The pollution sources of Suzhou Creek are mainly chemical substances, including the following categories: aerobic organic substances, refractory organic pollutants, heavy metals, acids, alkalis and some inorganic salts, and petroleum.
Located in the Yangtze River Delta, Shanghai is rich in water resources, but the deterioration of water quality in a large area has caused a relative shortage of water resources. Judging from the water quality, Shanghai is a water-deficient city.
To control water pollution, one is to control wastewater discharge, and the other is to treat the discharged sewage centrally. Shanghai 1993 completed the first phase of the confluence project and the recently successful second phase project are important measures to control water pollution. 1995, scientists put forward the cross strategy of radical treatment of Suzhou River environment, that is, "river closure, bottom cleaning, drainage, bend cutting and legislation". "sewage interception" means that sewage enters the pipeline to prevent it from being discharged into Suzhou River; "Bottom cleaning" means cleaning up the silt at the bottom of the river and cleaning up the pollutants accumulated over the years; "Drainage" means increasing the flow of fresh water in the upstream and constantly washing the pollution on the river; "Cutting the bend" is to transform the waterway, make it straight, and let the river flow smoothly; "Legislation" is to formulate laws and regulations specifically for Suzhou Creek management, and use laws to regulate people's behavior. Today, with the joint efforts of all citizens for nearly ten years, the odor of Suzhou River has been eliminated and the black color has faded. We will be proud of the beautiful water environment in Shanghai.
Water quality analysis usually includes the following test steps and contents:
1, sampling should pay attention to the sampling location, time, water depth, sampling bottle design, etc.
2. Sensory detection includes color, turbidity, odor, visible objects and organisms.
3. PH value of acidity test (6.5 ~ 8.5)
4. dissolved oxygen test dissolved oxygen refers to the amount of oxygen dissolved in water, usually recorded as DO, expressed in milligrams of oxygen per liter of water. The amount of dissolved oxygen is an index to measure the self-purification ability of water body.
5. Chemical oxygen demand (COD) test Chemical oxygen demand is the amount of oxygen consumed when oxidizable substances in water are chemically oxidized. Expressed in milligrams of oxygen consumption per liter of water, the greater the COD value, the more serious the water pollution (usually considered to be caused by organic matter).
6. Biochemical oxygen demand (BOD) test Biochemical oxygen demand refers to the amount of dissolved oxygen consumed in water when microorganisms decompose organic matter in groundwater. It is expressed in milligrams of dissolved oxygen consumed per liter of water. The greater the BOD value, the more serious the water pollution.
7, the total hardness of water, toxicological indicators (arsenic, cyanide, heavy metal ions and other toxic substances), bacteriological indicators (total bacteria, total coliforms, free residual chlorine, etc.). ) and other tests.
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"How much do you know about chemistry" series of tips
A, 2 1 century metal-titanium
Pure titanium is a silvery white metal. Titanium minerals are widely distributed in nature, accounting for about 0.6% of the earth's crust weight, second only to aluminum, iron, calcium, sodium, potassium and magnesium, but several times or even dozens of times more than copper, tin, manganese and zinc. The melting point of titanium is 1725℃, and its main characteristics are low density and high strength. Compared with steel, its density is only 57% of steel, while its strength and hardness are similar to steel. Compared with aluminum, although aluminum is less dense than titanium, its mechanical strength is poor. So titanium has the advantages of both steel (high strength) and aluminum (light weight). Pure titanium has good plasticity, twice the toughness of pure iron, and good heat resistance and corrosion resistance.
Because of these advantages, titanium has become an important rare metal since 1950s. Titanium and its alloys were first used to make airplanes, rockets, missiles, ships, etc. Now it is widely used in chemical and petroleum fields. For example, in the manufacture of supersonic aircraft, because the surface temperature of such aircraft is high when flying at high speed, aluminum alloy or stainless steel has lost its original properties at this temperature, while titanium alloy still maintains good mechanical properties above 550℃, so it can be used to manufacture high-speed aircraft that exceeds the speed of sound by three times. The titanium consumption of this kind of aircraft accounts for 95% of the total weight of its structure, so it is called "titanium aircraft". At present, more than half of the titanium in the world is used to manufacture important parts of aircraft bodies and jet engines. In the atomic energy industry, titanium is used to manufacture the main components of nuclear reactors. In the chemical industry, titanium is mainly used to manufacture various containers, reactors, heat exchangers, pipelines, pumps and valves. If only about 1% titanium is added to stainless steel, the rust resistance will be greatly improved.
Titanium can also form many compounds, and they also have various special properties and uses. For example, titanium dioxide is a snow-white powder and the best white pigment, commonly known as "titanium dioxide". 1 g titanium dioxide can paint an area of more than 450 square centimeters white. The amount of titanium dioxide used as a white pigment in the world is more than one year to several hundred thousand tons. If titanium dioxide is added to the paper, it can make the paper white and opaque. Therefore, it is sometimes necessary to add titanium dioxide to the paper used to make banknotes and artworks. In addition, titanium dioxide is sometimes added in order to lighten the color of plastic and soften the luster of rayon. Titanium dioxide is known as the whitest thing in the world.
Most of titanium in nature is in a dispersed state, mainly forming ilmenite, rutile and vanadium-titanium ore. Panzhihua, Sichuan, China is rich in vanadium-titanium iron ore, with a reserve of about 6543.8+0.5 billion tons.
In addition, titanium has a unique use in medicine and can be used to replace damaged bones, so it is called "bionic metal".
So, how was titanium discovered? 179 1 year, the British scientist Gregory discovered a kind of magnetic sand with black ore in the suburb of Minahan. Through the study of this kind of ore, he thinks that there is a new chemical element in the ore. And named this new element "Minahan" after the place where the ore was discovered.
Four years later, German chemist klapp Lott discovered this new element in a red ore in Anick, Hungary. He was named after the "Dan Tai" family in Greek mythology (in Chinese, it was called titanium according to the transliteration of its original name). Klapp Lott also pointed out that the new element "Minahan" discovered by Grigor was titanium, but what was discovered at that time was actually powdered titanium dioxide, not metallic titanium. It was not until 19 10 that American chemist Handel made metallic titanium with a purity of 99.9% for the first time, but the total amount was less than1g. It took 120 years from the discovery of titanium to the preparation of metallic titanium. It was not until 1947 that people began to smelt titanium in factories, with an annual output of only 2 tons. By 1955, the output soared to 20,000 tons. By 1972, the annual output will reach 200,000 tons.
The application of titanium is more and more extensive, and people pay more and more attention to it. People call it the future steel and 2 1 century metal.
Question: Please give some main functions of titanium.
Second, pens and chemistry.
Su Dongpo, a famous painter and painter in the Northern Song Dynasty, said that "there is a wonder in the world, the three rivers flow in parallel, and the pen is tilted", showing a picture of strokes. In ancient China, "pen" ranked first in Four Treasures of the Study, which highlighted the importance of pen. In today's society, the pen has more important practical significance.
1, pencil
There are two kinds of ordinary pencils. One is to fix pencil lead's pencil with wood; One is a movable pencil with pencil lead in a slender plastic tube. No matter what kind of pencil, the core part is to use pencil lead. Pencil lead is made of graphite and a certain proportion of clay. When more clay is added, the Hardness of pencil lead increases, and the pen is marked with the initials H of hard. On the contrary, the proportion of graphite increases, the hardness decreases, and the black color increases, with the black initials B. HB pencils with moderate hardness are suitable for children to learn and write, 6H pencils are often used for drawing, and 2B and 6B pencils are often used for drawing.
2. pen
The nib is made of special steel containing 5% ~ 10% chromium and nickel alloy respectively. Chromium-nickel steel has strong corrosion resistance and is not easy to oxidize. This is a kind of stainless steel. Among these pens, one is a pen dipped in ink. The other is a fountain pen, which has an ink storage device and flows to the nib when writing. The pen tip is made of alloy steel, and the pen tip is a convenient ball for the machine to roll out. This pen has good corrosion resistance, but poor wear resistance.
3. Golden pen
The gold pen is a high-grade fountain pen, with gold alloy as the nib and iridium alloy as the nib. There are two kinds of gold pens produced in China, one is14k; Gold 58.33%, silver 20.835% and copper 20.835%; The other is 50% Au, 25% Ag, 25% Cu, commonly known Au 50%% Au, that is, 12K. The gold pen is durable, wear-resistant, smooth and corrosion-resistant, and it is particularly elastic when writing. It is an ideal hard pen.
4. Iridium pen
The tip of iridium pen is also made of stainless steel. In order to change the wear resistance of the nib, iridium particles are placed at the tip of the nib to distinguish the pen from the iridium pen. The pen not only has good corrosion resistance and elasticity, but also has the characteristics of economy and durability, which is well received by consumers. It is the most produced and widely sold pen in China.
5, ballpoint pen
It is a pen that writes with different pigments. The pen tip is a small steel ball embedded in a small cylindrical copper bowl, and then connected to a plastic pipe filled with ink. The ink flows around with the rotation of the steel ball. This kind of pen is more durable than ordinary pen, but if it is used and kept improperly, it often cannot be written, mainly because the dry ink sticks around the steel ball to prevent the ink from flowing out. Ink is a kind of viscous oil, which is made of linseed oil, synthetic pine nut oil (mainly containing terpineol), mineral oil (oil obtained by fractionation of petroleum and other minerals), hard rubber, lampblack and so on. When using a ballpoint pen, don't write on paper with oil and wax, otherwise the oil and wax will be embedded in the copper bowl along the edge of the steel ball, which will affect the oil output and make it impossible to write. It is also necessary to avoid the impact and exposure of the pen, and wear gloves and a pen cap when not in use to prevent the damage of the pen tip and pen holder and the oil leakage of the pen core from polluting objects. If it is cold or not used for a long time. When the pen runs out of oil, you can put the nib in warm water for a while, and then use the nib to stroke on the paper to write.
Step 6 brush
As early as 3000 years ago in Shang Dynasty, China used the brush to write and draw, which is an ancient and vital pen. Brush can be divided into wool and wolf hair because of the different raw materials for making pens. Wool loops are really not made of goat hair, most of them are wool-free, and wolf hair is made of the hair on the tail of a weasel. Wool quilt is soft, elastic and weak, suitable for writing plump or delicate and thin characters. Wolf hair is hard and elastic, suitable for writing tall, straight, strong or beautiful small and medium letters. The newly bought nib has glue, so you should soak the bristles with clear water, then wash the glue and dip it in ink to write. After writing, wash the remaining ink, straighten the pen, cover the cap and put it in the pen. Brushes that are not used for the time being should be placed in a cool and ventilated place, and it is best to place sanitary essence near the bristles to prevent insects from eating.
7.chalk
This pen is made of calcium sulfate hydrate (commonly known as gypsum). You can also add various pigments to make colored chalk. In the production process, raw gypsum is heated to a certain temperature to partially dehydrate it into mature gypsum, and then the hot gypsum is stirred into paste with water and poured into a mold for solidification. Models, statues and medical gypsum bandages can be made by controlling the temperature and using the mutual variability of raw and cooked gypsum.
8, electric pen
An electrician's necessity, a pen used to measure whether an object has electricity. The electric pen looks like a pen, ballpoint pen and screwdriver. Regardless of its appearance, its construction principle is basically the same: the shell is mostly plastic insulator, and the inside is composed of metal conductor, small bulb and resistance wire. The small bulb is filled with a colorless inert gas (neon), which can produce red light with strong transmittance under the excitation of electric field. When the object is charged, use an electric pen to test the redness of the neon light bulb, otherwise the neon light bulb will not light up.
In addition, a stone pen made of talc; Made of high-carbon fatty acids, high-carbon monobasic fatty alcohols and various pigments-colored crayons; Pen for waxed paper-iron pen; Used for signature and writing-signature pen, fountain pen and artistic pen; For painting-charcoal pen, watercolor pen, painting pen, oil painting pen and combination pen; Made of different shapes-space pen, bamboo pen, vase pen, etc. The pen cover is made of different materials-national lacquer pen, gold-plated silver pen and cloisonne pen; There are also used for beauty and makeup-eyebrow pencil, eyeliner, lip pencil and so on.
Various colored pens help people learn knowledge, express ideas, promote communication and beautify the environment.
Question: Please name the main parts of several kinds of pens.
9. Why write important documents in carbon ink?