People who generally eat contaminated food get sick at the same time or successively. Although the symptoms may be different, if you can't tell whether it is poisoning or physical discomfort, you can call the local poisoning control center for help. Experts there will provide free poisoning prevention and first aid guidance and help, as well as special detoxification drugs and poison testing services. In most cases, under the guidance of experts in the poisoning control center, they can be treated by vomiting, taking absorbent drugs, resting, etc., or with the help of relatives and friends at home. If it is serious, experts will also guide you to a professional unit.
Fingerprint inspection
Principle: Iodine will sublimate into iodine vapor when heated. Iodine vapor can be dissolved in grease and other secretions on fingers to form a brown fingerprint.
Supplies: test tube, rubber stopper, medicine spoon, alcohol lamp, scissors, white paper, iodine.
Experimental steps: 1. Take a clean and smooth piece of white paper, cut it into a piece of paper about 4 cm long and less than the diameter of the test tube, and press several handprints on the paper with your fingers. 2. Take a sesame-sized iodine with a spoon and put it in a test tube. Hang the paper in the test tube (be careful not to stick the side with fingerprints on the tube wall) and plug it with rubber plugs. 3. Heat the test tube containing iodine to slightly above the flame of alcohol lamp, stop heating immediately after iodine vapor is generated, and observe the fingerprints on the paper.
Some new methods of hydrogen production course
Liang teaching material institute
In recent years, scientists all over the world have developed some new hydrogen production methods, and scientists in China have also tried some new hydrogen production methods. Now some new methods are introduced as follows: ceramics react with water to produce hydrogen. Scientists in tokyo institute of technology made ceramics react with water at 300℃ to produce hydrogen. They heated the nickel ferrite (CNF) of carbon to 300℃ in the flow of argon and nitrogen, and then injected water into CNF with an injection needle, so that the water contacted with the hot CNF to generate hydrogen. Since CNF returns to inactive state after water decomposition, ferrite can be reused. In each reaction, 2 ~ 3 cubic centimeters of hydrogen can be produced on average per gram of CNF. Enzymes extracted from microorganisms produce hydrogen glucose deoxyenzyme. Glucose deoxygenase was extracted from pyrogenic lactic acid bacteria in Oak Cen National Laboratory. Thermogenic lactic acid bacteria were first discovered in low-temperature dry distillation coal cinder in American mines. With the help of nicotinamide adenine dinucleotide phosphate (NADP), glucose deoxyenzyme can extract hydrogen from glucose. In the process of producing hydrogen, NADP stripped a hydrogen atom from glucose, making the remaining substances into a hydrogen atom solution. Hydrogen production by bacteria Many primitive lower organisms can also release hydrogen during metabolism. For example, many bacteria can release hydrogen under certain conditions. A bacterium named Trichomonas rubra was discovered in Japan, and it is an expert in hydrogen production. In glassware, this kind of bacteria can be cultivated by using starch as raw material and adding some other nutrients to make culture solution. For every 5 mm starch nutrient solution consumed, 25 ml hydrogen can be produced.
Hydrogen production by green algae
Scientists have discovered a new method that allows green algae to produce hydrogen as needed. Scientists at the University of California, Berkeley, say that green algae is one of the oldest plants known to mankind, and it has evolved the ability to live in two completely different environments. When green algae live in ordinary air and sunlight, it will carry out photosynthesis like other plants. Photosynthesis uses sunlight, water and carbon dioxide to produce oxygen and chemicals that plants need to sustain life. However, when green algae lack sulfur, a key nutrient, and are placed in an anaerobic environment, green algae will return to another way of life in order to survive. In this case, the green algae will produce hydrogen. According to scientists, 1 liter of green algae culture solution can produce 3 ml of hydrogen per hour, but researchers believe that the efficiency of hydrogen production by green algae can be improved by at least 100 times.
Artificial snowfall
Since ancient times, God has always been willing to snow, but not willing to. Is there any way to make God make it snow according to human needs? There is a way, and that is artificial snowfall. There are two conditions for water vapor in the sky to turn into rain and snow. First, it must have a certain degree of water vapor saturation (mainly related to temperature), and second, it must have condensation nuclei. Therefore, artificial snowfall must first have clouds in the sky. There is no cloud, just like a clever woman can't cook without rice, and it won't snow. The cloud that can snow is the "Leng Yun" below 0℃. In the cold cloud, there are both small water droplets and small snow crystals condensed by water vapor. But they are all very small and light. If there are no conditions to continue to grow, they can only be suspended in the air like smoke, and it is difficult to fall. In winter, we often see large clouds, but we can't see snowflakes floating down, because the snow crystals that make up these clouds are too small to overcome the buoyancy of the air and have poor precipitation ability. If some particles are sprayed in the cloud to promote the rapid growth of snow crystals to overcome the buoyancy of the air, this is the credit of artificial snowfall.
What substance can be sprayed to promote the rapid growth of snow crystals? In the early days, people showed their magical powers and used many interesting methods. These methods mainly include: burning on the ground and releasing a lot of smoke into the sky; Attack the clouds with artillery; Fly high in the clouds with a kite, then electrify the kite and flash flowers; Fly into the clouds and spray liquid water droplets and dust particles. However, the effects of these methods are not ideal. It was not until 1946 that people discovered that millions of snow crystals could be formed by throwing tiny dry ice particles into the Leng Yun. 1l On June 3rd, 2008, someone scattered dry ice particles on the top of the cumulus cloud with the temperature of -20℃ on the plane and found that snow had fallen from this cloud.
The dry ice mentioned here is not water-frozen ice, but the solid state of carbon dioxide, much like compacted snow in winter. The temperature of dry ice is very low, below -78.5℃. Spraying dry ice crystals in cold clouds is like scattered flowers, and each carbon dioxide crystal becomes a dramatic cooling center, which makes water vapor, small water droplets and small snow crystals in cold clouds quickly gather around it and condense into larger snowflakes. How to diffuse these condensed nuclei into the cloud? Modern people mostly use cannons to put chemicals in shells, and then use cannons to shoot shells into the clouds. However, this method does not spray evenly, which wastes a lot of drugs and increases the cost of artificial snowfall. Some people put them in earth rockets and let them fly into the clouds to spray.
Manifestations of pesticide-contaminated food poisoning
Whether people will have poisoning symptoms after eating food with pesticide residues depends on the types of pesticides and the amount of pesticides entering the body. Not all foods contaminated with pesticides can cause poisoning. If the pollution is light, people may not have obvious symptoms when eating a small amount, but they often have systemic symptoms such as headache, dizziness, fatigue, nausea and poor mental condition. When the pesticide pollution is serious and the amount of pesticide entering the body is large, obvious discomfort may occur, such as fatigue, vomiting, diarrhea, muscle tremor and palpitation. In severe cases, general convulsions, coma, heart failure and other manifestations may occur, which may lead to death. The manifestation of poisoning also depends on the type of poison. The main types of poisoning caused by pesticide residues are methamidophos, parathion (1605), methyl parathion, phorate, omethoate and carbofuran.
Human taste pollution
There are more than 400 metabolites in human body. There are 149 species excreted by breathing, 229 species excreted by urine, 196 species excreted by feces, 15 1 species excreted by sweat, 27 1 species excreted by skin, and so on. Emissions include carbon dioxide, carbon monoxide, hydrocarbons, acetone, benzene, methane, aldehydes and so on. In the case of air circulation, pollutants will spread rapidly and you won't feel any smell. If there are many people in the room and cabin and the ventilation is not good, it will be full of "human flavor".
How to remove pesticide residues in vegetables
There are several simple ways to remove pesticide residues from vegetables and fruits at home:
Bubble washing method: the pesticides contaminated by vegetables are mainly organophosphorus pesticides, which are insoluble in water. This method can only remove some contaminated pesticides. But water washing is the basic method to remove other pollutants and residual pesticides in vegetables and fruits. Mainly used in leafy vegetables, such as spinach, day lily, leek flower, lettuce, Chinese cabbage and so on. Generally, the dirt on the surface should be washed off with water first, and then soaked in clear water for not less than 10 minute. Fruit and vegetable cleaning agent can increase the dissolution of pesticides, so a small amount of fruit and vegetable cleaning agent can be added during soaking. Rinse with running water for 2-3 times after soaking.
Peeling method: There are relatively many pesticides on the surface of vegetables and fruits, so peeling is a good way to remove residual pesticides. Can be used for apples, pears, kiwis, cucumbers, carrots, white gourd, pumpkins, zucchini, eggplant, radishes, etc. When processing, it is necessary to prevent mixed pollution of peeled vegetables and fruits again.
Storage method: pesticides will slowly decompose into harmless substances in the environment over time. Therefore, fruits and vegetables that are easy to preserve can be preserved for a certain period of time with less pesticide residues. Suitable for apple, kiwi, wax gourd and other non-perishable varieties. Generally stored 15 days or more. At the same time, it is suggested that the newly picked fruits should not be peeled and eaten immediately.
Heating method: the decomposition of carbamate pesticides is accelerated with the increase of temperature. Therefore, some vegetables and fruits that are difficult to treat by other methods can be heated to remove some pesticides. Commonly used in celery, spinach, Chinese cabbage, cabbage, green pepper, cauliflower, beans and so on. Clean the dirt on the surface with clear water, put it in boiling water for 2-5 minutes, and then rinse it with clear water 1-2 times.
What are minerals?
All aspects of human life, such as food, clothing, housing and transportation, are inseparable from minerals. For example, all kinds of materials needed to build a house, precious stones carried with you, and daily edible salt all come from minerals. What are minerals?
Only substances that meet the following conditions can be called minerals:
1) Minerals are natural compounds or simple materials formed by various geological processes, such as volcanism. They can be solid (such as seasonal diamonds), liquid (such as natural mercury), gas (such as water vapor in volcanic jets) or colloid (such as opal).
2) Minerals have a certain chemical composition. For example, the composition of a diamond is elemental carbon (C), which should be silica (SiO2), but the natural mineral composition is not completely pure and often contains a small amount of impurities.
3) Minerals also have a certain crystal structure, and their atoms are arranged regularly. For example, the timely crystal arrangement is that the four corners of silicon ions are connected with an oxygen ion to form a tetrahedron, and these tetrahedrons are connected with each other at the corners to form a three-dimensional frame structure.
If there is enough room for growth, all solid minerals have certain forms. For example, diamonds form octahedral shapes, and cylinders with horizontal stripes are often formed on cylinders when necessary. When there is no room for growth, their inherent forms cannot be expressed.
4) Minerals have relatively stable physical properties. For example, galena is steel gray, bright metallic luster and opaque, and its powder (streaks) is black and soft (can be scraped with a knife).
Diamonds fly out of graphite powder
When it comes to diamonds, people will think of dazzling and glittering scenes, which shine with the owner's activities. But because of its high price, most people can only flinch. Despite this, people are still eager for diamonds. Do you know what a diamond is? Its chemical composition is carbon (C), and natural diamonds can only be called "diamonds" after being polished. Natural diamonds are very rare. There are only two diamonds weighing more than 1 000 carats (1g = 5 carats) in the world, and there are very few diamonds weighing more than 400 carats. The largest diamond found in China so far weighs 1588.786 carats, which is called "Chang Lin diamond". That thing which is rare is dear. Because there are few natural diamonds that can be used as "diamonds", people want to use "artificial" diamonds instead, and naturally think of the "twin" brother of diamonds-graphite.
The chemical composition of diamond and graphite is carbon (C), which is called "allotrope". From this title, we can know that their "quality" is the same, but their "shape" or "nature" is different, and there is a world of difference. Diamond is the hardest substance at present, but graphite is one of the softest substances.
The hardness difference between graphite and diamond is so great, but people still hope to obtain diamond through artificial synthesis because graphite (carbon) is rich in nature. But it is not so easy to change the carbon in graphite into carbon arranged like diamond. Graphite can be transformed into diamond at 50000-60000 atmospheres ((5-6)× 103 MPa) and 1000-2000 degrees Celsius, and then iron, cobalt and nickel are used as catalysts.
At present, more than a dozen countries (including China) have synthesized diamonds. However, due to its fine particles, this kind of diamond is mainly used as an abrasive and as a drilling bit for cutting and geological and oil drilling. At present, 80% of the global diamond consumption is mainly used in industry, and the output far exceeds that of natural diamonds.
The diamond particles initially synthesized are black, with a size of 0.5 mm and a weight of about 0. 1 carat (the smallest diamond used for gemstones should not be less than 0. 1 carat). At present, the large-particle diamond developed in China is more than 3mm, and the United States and Japan have made 6. 1 Klado diamond. We say that diamonds have "flown" out of graphite, and gem-grade synthetic diamonds will also be supplied to the market in the near future.
World Water Day
March 22nd 1999 is the seventh World Water Day and the first day of New China Water Week. The Agriculture Committee of the National People's Congress, the Environmental Protection Committee and the Ministry of Water Resources jointly held a commemorative forum in Beijing, calling on the whole society to pay more attention to China's water resources. Water is an irreplaceable resource for human survival and development, and it has increasingly become a restrictive factor for the sustainable development of the global economy and society. In order to arouse the world public's attention to water issues, the 47th United Nations General Assembly 1993 designated March 22nd as World Water Day.
The theme of this year's World Water Day is "Everyone lives downstream", which aims to remind people to consider the interests of downstream residents when developing and utilizing water resources. As China draws more and more water from the Yellow River to meet the needs of its economic growth, the Yellow River began to fail to meet the water supply demand 25 years ago. 1972 The water level of the Yellow River dropped sharply, which led to the first dry-up of the Yellow River in the long history of China. In that year, the Yellow River was cut off for 15 days, and then it was cut off intermittently for 10 years. Since 1985, the Yellow River has been cut off every year, and the cut-off time is getting longer and longer. 1996 Yellow River cut off 133 days. During the period of 1997, the Yellow River was cut off for 226 days due to drought. This year, the river failed to flow to Shandong Province, the last province where the Yellow River entered the sea for a long time.
In addition, the increasingly serious water pollution will also cause water shortage. Pollution occurs when harmful substances in water exceed the self-purification ability of water body. These harmful substances include toxic substances, such as pesticides, heavy metals and their compounds, organic and inorganic chemicals, pathogenic microorganisms, oils, plant nutrients, various wastes and radioactive substances. The sources of water pollution are mainly untreated industrial wastewater, domestic wastewater and hospital sewage.
Water pollution is very harmful to human health. Pathogenic microorganisms and viruses in sewage can cause the spread of infectious diseases. Toxic substances in water can poison people and animals, and some highly toxic substances can kill creatures in water and people who drink water in a few minutes. This situation is easier to find. The most dangerous thing is the pollution of metal compounds such as mercury, cadmium, chromium and aluminum, which will cause chronic poisoning after entering the human body. Once found, it cannot be stopped. According to the survey of the World Health Organization (WHO), 70% people in the world do not have access to safe and hygienic drinking water. At present,150,000 children under the age of five die every year in the world, and most of the causes of death are related to drinking water. According to the statistics of the United Nations, 25,000 people around the world get sick or die from lack of water every day because of drinking polluted water.
Discovery of acid rain
The modern industrial revolution, starting with the steam engine, the boiler burns coal, produces steam and drives the machine; As a result, the coal consumption of thermal power plants has increased rapidly. Unfortunately, coal contains impurity sulfur, about 1%, which will release acid gas SO2 when burning. The high temperature produced by combustion can also promote some chemical changes in the combustion-supporting air. Oxygen combines with nitrogen and releases acid gas nitrogen oxides. They were washed and dissolved by rain and snow in the sky, and the rain turned into acid rain; These acidic gases become impurities such as sulfate, nitrate and ammonium ions in rainwater. From 65438 to 0872, the British scientist Smith analyzed the composition of rainwater in Renton and found that it was acidic. The rainwater in rural areas contained ammonium carbonate, not acidic. The rainwater in the suburbs contains ammonium sulfate, which is slightly acidic; Urban rainwater contains sulfuric acid or acidic sulfate, which is acidic. So Smith put forward the proper term "acid rain" for the first time in the book Air and Rainfall: The Beginning of Chemical Climatology.
Sanitary drinking water and chemistry
Water boiled for a long time on the stove, water boiled repeatedly in the electric water heater. Because this kind of water boils for a long time, it contains many inactive substances, such as heavy metal components such as calcium and magnesium and nitrite. Drinking this water for a long time will interfere with people's gastrointestinal function and cause temporary diarrhea and bloating; Toxic nitrite can also cause hypoxia in the body, which can lead to coma, convulsion and even death in severe cases.
The tap water that people drink is chlorinated and disinfected. 13 A variety of harmful substances can be separated from chlorine-treated water, among which halogenated hydrocarbons and chloroform also have carcinogenic and teratogenic effects. When the water temperature reached 90℃, the content of halogenated hydrocarbons increased from 53 micrograms per kilogram to 177 micrograms, which was twice as high as the national sanitary standard for drinking water. Experts point out that drinking boiled water will increase the possibility of bladder cancer and rectal cancer by 2 1%-38%. When the water temperature reaches 100℃, these two harmful substances will be greatly reduced with the evaporation of steam. If boiling lasts for 3 minutes, it is safe to drink.
acid rain
Simply put, acid rain is acid rain.
What is acid? Pure water is neutral and tasteless; Lemonade and orange juice are sour, and vinegar is sour. They are all weak acids. Baking soda water's alkalinity is slightly astringent, while caustic soda water has astringent taste and strong alkalinity. They are alkali. Scientists have found that acidity is related to the concentration of hydrogen ions in aqueous solution; The alkaline taste is related to the concentration of hydroxyl ions in aqueous solution; Then an index is established: the negative value of the logarithm of hydrogen ion concentration is called pH value. So the pH value of pure water is 7; The greater the acidity, the lower the pH value. The greater the alkalinity, the higher the pH value. The unpolluted rain and snow are neutral, and the pH value is close to 7. When it is saturated with carbon dioxide in the atmosphere, it is slightly acidic with a pH value of 5.65. Rain with pH less than 5.65, which is polluted by acidic gases in the atmosphere, is called acid rain. Snow with pH less than 5.65 is called sour snow; Fog that spreads at high altitude or high mountains (such as Mount Emei) is called acid fog when its pH value is less than 5.65.
The modern industrial revolution, starting with the steam engine, the boiler burns coal, produces steam and drives the machine; As a result, the coal consumption of thermal power plants has increased rapidly. Unfortunately, coal contains impurity sulfur, about 1%, which will release acid gas SO2 when burning. The high temperature produced by combustion can also promote some chemical changes in the combustion-supporting air. Oxygen combines with nitrogen and releases acid gas nitrogen oxides. They were washed and dissolved by rain and snow in the sky, and the rain turned into acid rain; These acidic gases become impurities such as sulfate, nitrate and ammonium ions in rainwater. From 65438 to 0872, the British scientist Smith analyzed the composition of rainwater in Renton and found that it was acidic. The rainwater in rural areas contained ammonium carbonate, not acidic. The rainwater in the suburbs contains ammonium sulfate, which is slightly acidic; Urban rainwater contains sulfuric acid or acidic sulfate, which is acidic.
Life in a drop of water
A drop of water, crystal clear, can't see anything with the naked eye. Put it under the microscope, hey, it's really special! Look, there are shiny "straps", slender "pins", flat "disks" and even exquisite "iron anchors" ... dazzling. What are these? This is plankton. Plankton is very short, mostly only a few thousandths to a few hundredths of a centimeter, so it is invisible to the naked eye. Their swimming skills are not high, and some of them can't swim at all, just go with the flow. But don't underestimate these little people, they are very fertile! If an individual plankton develops in a suitable environment, it can fill the whole water body in a few days! Even limited by various natural conditions, their number is still considerable, and they can be called "big families" in the water.
Without sunlight, phytoplankton can't survive, so most of them live on sunny water.
Although phytoplankton are small, they are producers of raw food in water. Without them, large creatures in the water may not survive. Plankton is the main bait of fish and a part of human food source. Working people in China's coastal areas have already used tidal currents to catch large plankton such as krill and shrimp, but due to various conditions, they cannot catch a large number of them. In the future, through further research and practice, it is very promising to better grasp the distribution law of plankton, continuously improve fishing technology and regard plankton as the direct food source of human beings.
Everything is split in two. Although plankton has important economic significance, not all plankton are beneficial. Some plankton are harmful to fish. Such as cyanobacteria and ANABAENA. Breeding in large numbers in hot weather makes the water quality worse, which seriously affects the normal life of fish and other aquatic organisms and even causes a large number of fish deaths. From 1946 to 1947, there are many poisonous phytoplankton in the Gulf of Mexico, resulting in a large number of fish deaths. The sea stinks, which seriously hinders people's breathing. This phenomenon occurs to varying degrees in the coastal areas of China. /kloc-in the autumn of 0/972, a large amount of yellow-brown dirt floated on the sea surface of the East China Sea, with an unpleasant smell. Fishermen call it "smelly water", which is caused by the proliferation of oscillatoria.
It is an important measure to use the beneficial side of plankton to prevent the harmful side and turn harm into benefit.
carbon monoxide
Carbon monoxide is inhaled through the respiratory tract. Inhaled CO enters the blood through alveoli and immediately combines with hemoglobin to form carboxyhemoglobin, which leads to hypoxemia and tissue hypoxia. The central nervous system is the most sensitive to hypoxia, so it is the first to participate. Common manifestations are: mental disorder, aphasia, blindness and so on. To quickly move the patient away from the poisoning site to a ventilated place, loosen the collar, pay attention to keep warm, and closely observe the state of consciousness. Timely and effective oxygen supply is the most important treatment principle for acute carbon monoxide poisoning. Hyperbaric oxygen therapy is used to quickly correct tissue hypoxia.