Science and technology

Two hydrogens can form a diatomic molecule H2, which exists in gaseous form at room temperature and is therefore referred to as hydrogen. Hydrogen molecules are composed of covalent bonds, and the modern theory of covalent bonds begins with quantum mechanical studies of hydrogen molecules. Hydrogen is a clean energy source that combines with oxygen to release a lot of heat. At the same quality, the heat released by hydrogen combustion is more than four times that of coal, and its reaction product is water, which is harmless to the environment...

3D printing, a new type of manufacturing technology, is receiving more and more attention. Conventional manufacturing techniques generally process a single piece of material into the required size and...

First, we have to figure out what the background radiation is. Many people may first think of these four words as the concept of physics "cosmic background radiation" or "universe microwave background radiation." In fact, background radiation, also known as background radiation, is a concept in the field of radiation safety and protection. We know that radiation can be divided into ionizing radiation and non-ionizing radiation according to whether it can ionize atoms and molecules. The former includes particles such as α particles, β particles, neutrons, etc...

When it comes to glue or adhesive, the first thing that everyone thinks of is the glue that is contained in the small bottle. When it is used, it can be applied to the object to be bonded. However, some adhesives are separately contained in two containers, and the two parts must be mixed evenly before use, otherwise, they will not work. Such an adhesive is commonly known as AB glue. AB glue is much more complicated in form than ordinary adhesives, and it is more troublesome to use. So why do we develop...

There is a "Chicago school" in the economics field. They believe that everyone is very rational when making choices. They will definitely make their own decisions. Therefore, the government should not interfere with individual freedom and let people freely choose what they want. lifestyle. This school is very influential in the economics field and is the theoretical basis of "neoliberalism." However, there have been people who have questioned this theory and accused it of overestimating human judgment...

"Just do not play, good baby changes." This old saying is tantamount to clichés for modern child educators, but it still makes sense when discussing the relationship between early childhood education and games. Although the Greek philosophers Plato and Aristotle have long discussed the role of games in education, the special "early education-game" theory did not begin to develop until hundreds of years later. Game as a treatment In 1920, Sigmund Freud proposed a psychoanalytic game theory in his book The Principles of Beyond Happiness...

The University of Munich in Germany studied a group of people aged 14-94 and found that the older people feel the faster they have experienced in the past 10 years, but they are no longer "accelerated" after the age of 50. Studies at the University of Oberlin and Duke University have found similar patterns: for hours to months, both old and young feel the same, but for the last 10 years, older people feel better than young people. fast. In 2013, the blink of an eye passed. You and your friends have...

An interesting study found that the more unfamiliar a student's name is, the more likely it is that there will be poor academic performance and even psychological problems. The two professors believe that a rare name will have a negative psychological impact on its owner. Many of the significant effects on names on behavior are attributed to self-suggestion. However, what is the truth? In 1948, two professors at Harvard University published a study of 3,300 newly graduated boys. The study explored the impact of student names on their academic performance...

According to a network news report during the National Day of 2013, 110,000 people watched the flag-raising and left 5 tons of garbage. Some people think that this is a false news, because 5 tons = 5000 kilograms, 110000 ÷ 5000 = 22 kilograms/person, and each person carrying 22 kilograms (44 pounds) of garbage is impossible. I have seen a saying before: 10 cm × 10 cm = 100 cm = 1 m, and 0.1 m × 0.1 m = 0.01 m = 1 cm, so 10 cm is not equal to 0.1 m. Of course, the above two examples are all wrong, the error is misused in the unit...

The best way to promote an esoteric theory or point of view is to create an interesting and impressive analogy, the butterfly effect, which clearly goes into TOP10, although one hundred people who talk about the butterfly effect may actually understand it. None of the people, including the author, did not hinder the popularity of the word. Even Hollywood has used this word to shoot three movies. Of course, the main theme in the movie is a desperate love. The word butterfly effect comes from the title...

It is no secret that there are many bacteria in the human body, on the surface of the skin, in the respiratory tract and in the intestines. If the human body is compared to mainstream society, then these bacteria are triads. Most of them have no name, no hukou, no preparation, and they are parasitic in some places in the human body. They rely on "stealing" for a living. Running out is awkward. The above is the traditional understanding of human parasitic bacteria. But when scientists began to study them seriously, they found that the real situation was much more complicated...

We tend to think that all the characteristics of animals and plants are produced in order to adapt to the environment under the influence of natural selection. In fact, many features are neither an adaptation to the environment nor a result of natural selection. Why do many people choose to watch simple TV and eat simple microwave food after a hard day? Is this because of convenience or the result of evolution over millions of years? We are accustomed to the assumption that all aspects of our body...