The discovery of C60 originated from the research in the field of astronomy. Scientists were initially interested in carbon dust widely distributed in stars. Scholars have found that the black cloud of interstellar carbon dust contains molecules composed of short-chain atoms, and some scholars believe that this cloud is produced by the red giant of carbon stars. Theoretical astronomers speculate that these dusty soils contain black carbon particles.
Later, in order to find out the molecular structure of carbon produced by red giant stars, Croft of Britain confirmed several molecules of carbon in interstellar dust. Hoffman in the United States and Clatchy Mo Ye in Germany created similar dust in the universe. They compared it with the black substance left by coal combustion and found that the vaporized substance left a clear trace in the ultraviolet absorption experiment, which was called "hump spectrum". Later, Cole, smalley of the United States and Croft of the United Kingdom explained the reasons for this phenomenon and won the Nobel Prize in chemistry.
C60 molecule is a molecule composed of 60 carbon atoms, which looks like football, so it is also called soccer ene. C60 is a stable molecule composed of carbon atoms. It has 60 vertices and 32 faces, of which 12 is a regular pentagon and 20 are regular hexagons. Its relative molecular mass is 720. C60 is a newly discovered carbon cluster in the mid-1980s. It is a simple substance, an allotrope of graphite and diamond. C60 has a broad application prospect.
How was carbon 60 discovered? C60 molecule C60 molecule is a molecule composed of 60 carbon atoms. It looks like a football and is a very stable molecule, which is mainly used in material science, superconductors and so on. Structural diagrams of diamond, graphite and C60 molecules. The world-famous football olefin-C60. C60 molecule is a stable molecule composed of 60 carbon atoms. It has 60 vertices and 32 faces, of which 12 is a regular pentagon and 20 are regular hexagons. It looks like football, so it is also called soccer ene. Soccer alkene was put forward by clotho (H.W.) and Smali (R.E.) of Rice University in Houston, USA in 1985. They bombarded graphite with a high-power laser beam to vaporize it, and used helium with a pressure of 1MPa to generate ultrasonic waves, so that the carbon atoms vaporized by the laser beam expanded in vacuum through a small nozzle and cooled rapidly. The composition and structure of C60 have been confirmed by mass spectrometry, X-ray analysis and other experiments. In addition, many molecules similar to C60, such as C70, have been found. 199 1 year, scientists found that C60 doped with a small amount of a certain metal has superconductivity, and the manufacturing process of this material is simpler than that of the traditional superconducting material-ceramics, and the texture is very hard, so people predict that C60 will have broad application prospects in the field of superconducting materials. Carbon 60 molecule, commonly known as buckyball, consists of 60 carbon atoms, forming a cage structure. This molecule was discovered in 1985. Because of its special properties, it has been the focus of chemists' research.
How was DNA discovered? The discovery of DNA
Since Mendel's genetic law was rediscovered, people have raised another question: Are genetic factors material entities? In order to solve the problem of what genes are, people began to study nucleic acids and protein.
As early as 1868, people have discovered nucleic acids. In the laboratory of German chemist Hope Sailor, there is a Swiss graduate student named Michel (1844- 1895). He is very interested in the bandages with purulent blood thrown by a hospital near the laboratory, because he knows that purulent blood is the "remains" of white blood cells and human cells that died in the "battle" with germs in order to protect human health. So he carefully collected the purulent blood on the bandage and decomposed it with pepsin. As a result, he found that most of the cell debris was decomposed, but it had no effect on the nucleus. He further analyzed the substances in the nucleus and found that the nucleus contained a substance rich in phosphorus and nitrogen. Hope Sailor experimented with yeast, which proved that Michelle found the substance in the nucleus correct. So he named this substance separated from the nucleus "nuclide", and later found that it was acidic, so it was renamed "nucleic acid". Since then, people have carried out a series of fruitful research on nucleic acid.
At the beginning of the 20th century, the German pirate ship (1853- 1927) and his two students, Jones (1865- 1935) and Levin (1869-1. Nucleotides are composed of bases, ribose and phosphoric acid. There are four kinds of bases (adenine, guanine, thymine and cytosine) and two kinds of ribose (ribose and deoxyribose), so nucleic acids are divided into ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).
Levin, who was eager to publish his own research results, mistakenly thought that the amount of four bases in nucleic acid was equal, and thus deduced that the basic structure of nucleic acid was four nucleotides connected by four different bases, which were polymerized into nucleic acid, and put forward the "four-nucleotide hypothesis". This false assumption greatly hinders the understanding of complex nucleic acid structure, and also affects people's understanding of nucleic acid function to some extent. It is believed that although nucleic acid exists in an important structure-the nucleus, its structure is too simple to imagine what role it can play in the genetic process.
Protein's discovery was 30 years earlier than that of nucleic acid, and it developed rapidly. 12 of the 20 amino acids that make up protein was found in the 20th century, and all of them were found in 1940.
1902, the German chemist Fischer put forward the theory that amino acids are linked by peptide chains to form protein. 19 17 years, he synthesized a 18 peptide chain consisting of 15 glycines and 3 leucines. Therefore, some scientists think that protein may play a major role in heredity. If heredity involves nucleic acid, it must be a nucleoprotein linked with protein. So at that time, the biological community generally tended to think that protein was the carrier of genetic information.
1928, American scientist Griffith (1877- 194 1) experimented on mice with a highly toxic pneumococcus with an envelope and an attenuated pneumococcus without an envelope. He killed pod bacteria with high temperature and injected them into human mice with live bacteria without pods. As a result, he found that the mouse soon became ill and died, and at the same time, he isolated live pod bacteria from the blood of the mouse. This shows that Agabi actually got something from the dead Agabi and turned Agabi into Agabi. Is this assumption correct? Griffith did another experiment in the test tube, and found that when dead bacteria and living bacteria without pods were cultured in the test tube at the same time, all bacteria without pods became pods, and found that it was the residual nucleic acid in the shell of dead bacteria with pods that made bacteria without pods grow protein pods (because the nucleic acid in pods was not destroyed during heating). Griffith called nucleic acids "transforming factors".
1944, American bacteriologist Avery (1877- 1955) isolated an active "transforming factor" from American bacteria, and made an experiment to test the existence of protein. The result is negative, which proves that the "transforming factor" is DNA. However, this discovery has not been widely recognized. People suspect that the technology at that time could not remove protein, and the residual protein played a role in transformation.
The phage group of German-American scientist delbruck (1906- 198 1) firmly believes Avery's discovery. Because they observed the morphology of phage and the growth process of Escherichia coli under electron microscope. Phage is a virus that takes bacterial cells as its host. It is so small that it can only be seen with an electron microscope. It is like a tadpole, with a head membrane and a tail sheath composed of protein. The head contains DNA, and the tail sheath has tail silk, substrate and small hook. When phage infects Escherichia coli, the tail end is first tied to the bacterial cell membrane, and then all the DNA inside is injected into the bacterial cell. Protein's empty shell is left outside the bacterial cells, which has no effect. After phage DNA enters bacterial cells, phage DNA and protein are rapidly synthesized by using substances in bacteria, thus many new phages with the same size and shape as the original ones are replicated. It was not until the bacteria completely disintegrated that these phages left the dead bacteria and infected other bacteria.
1952, Hershey (1908 I), the main member of phage group, and his student Chase used advanced isotope labeling technology to do the experiment of phage infecting Escherichia coli. He labeled the nucleic acid of E.coli T2 phage with 32P and the protein shell with 35S. Escherichia coli was infected with T2 phage, and then it was isolated. Results Phage left an empty shell with 35S label outside E.coli, only the nucleic acid with 32P label inside the phage was injected into E.coli, and the phage successfully propagated in E.coli.. This experiment proves that DNA has the function of transmitting genetic information, and protein is synthesized by the instructions of DNA. This result was immediately accepted by the academic community.
Almost at the same time, Austrian biochemist Chagav (1905-) re-determined the content of four bases in nucleic acid, and achieved results. Under the influence of Avery's work, he thinks that if different biological species are due to different DNA, then the structure of DNA must be very complicated, otherwise it will be difficult to adapt to the diversity of the biological world. Therefore, he doubted Levin's "Tetranucleotide Hypothesis". During the four years of 1948- 1952, he used paper chromatography which was more accurate than that of Levin's time, separated the four bases and made quantitative analysis by ultraviolet absorption spectrum. After repeated experiments, he finally got a different result from Levin. The experimental results show that the total number of purines and pyrimidines in DNA macromolecules is equal, among which the number of adenine A and thymine T is equal, and the number of guanine G and cytosine C is equal. It shows that the bases A and T, G and C in DNA molecules exist in pairs, thus denying the "tetranucleotide hypothesis" and providing important clues and basis for exploring the molecular structure of DNA.
1On April 25th, 953, the British magazine Nature published the research results of Watson and Crick in Cambridge University: the molecular model of DNA double helix structure, which was later hailed as the greatest discovery of biology since the 20th century, marking the birth of molecular biology.
Watson (1928 I) was an extremely clever boy in middle school. He entered the University of Chicago at the age of 15. At that time, because of an experimental education plan that allowed early study, Watson had the opportunity to study the biological science course in all aspects. During his college years, Watson had little formal training in genetics, but since reading Schrodinger's What is Life? -the physical appearance of living cells ",prompted him to" discover the secret of genes ". He is good at brainstorming, learning from others and enriching himself with other people's ideas. As long as there are convenient conditions, you can get the knowledge you need without forcing yourself to learn the whole new field. Watson received his doctorate at the age of 22 and was sent to Europe for postdoctoral research. In order to fully understand the chemical structure of a virus gene, he went to the laboratory in Copenhagen, Denmark to study chemistry. Once he and his tutor went to Naples, Italy to attend a biomacromolecule conference, and had the opportunity to listen to a lecture given by British physical biologist Wilkins (19 16-), and saw the DNAX-ray diffraction photos of Wilkins. Since then, the idea of finding the key to unlock the DNA structure has been retrieved in Watson's mind. Where can I learn to analyze X-ray diffraction patterns? So he went to the Cavendish laboratory of Cambridge University in England to study, during which Watson met Crick.
Crick (19 16) was enthusiastic about science when he was in middle school, and 1937 graduated from London University. In 1946, what does he read about life? -predicted the physical appearance of living cells, determined to apply the knowledge of physics to the study of biology, and became interested in biology from then on. 1947, repeat graduate student. 1949, he and Peruz used X-ray technology to study the molecular structure of protein, so they met Watson here. At that time, Crick was older than Watson 12 years old, and had not yet obtained his doctorate. But they talked very speculatively, and Watson felt lucky to find someone here who knew that DNA was more important than protein. At the same time, Watson thinks Crick is the smartest person he has ever met. They talk for at least a few hours every day to discuss academic issues. Two people complement each other, criticize each other and inspire each other. They believe that solving the molecular structure of DNA is the key to solving the genetic mystery. Only with accurate X-ray diffraction data can we find out the structure of DNA more quickly. In order to get the data of DNAX-ray diffraction, Crick invited Wilkins to Cambridge for the weekend. In the conversation, Wilkins accepted the view that DNA structure is spiral, and also talked about his collaborator Franklin (1920- 1958, female) and the scientists in the laboratory, who were also thinking hard about the problem of DNA structure model. From 195 1 year1month to1April, 9531August, Watson and Crick had several important academic exchanges with Wilkins and Franklin.
195 1 year1month, Watson was deeply inspired after listening to Franklin's detailed report on DNA structure. Watson and Crick, who have a certain understanding of crystal structure analysis, realize that if they want to build a DNA structure model quickly, they can only use other people's analysis data. They quickly put forward the idea of triple helix DNA structure. 195 1 At the end, they invited Wilkins and Franklin to discuss this model. Franklin pointed out that they underestimated the water content of DNA by half, so the first model failed.
One day, Watson went to Wilkins Laboratory at King's College, and Wilkins took out a recent X-ray diffraction photo of Franklin's "B-type" DNA. Watson immediately got excited when he saw the photo, and his heart beat faster, because this kind of image is much simpler than the "A-type" obtained before. Just look at the "B-type" X-ray diffraction photos, and then after simple calculation, we can determine the number of polynucleotide chains in DNA molecules.
Crick asked a mathematician to help him calculate, and the results showed that Yuanyin had a tendency to attract pyrimidine. According to this result and the result that two purines and two pyrimidines of nucleic acid obtained from Chagaff are equal to each other, they formed the concept of base pairing.
They think hard about the sequence of four bases, draw the base structure on paper again and again, fiddle with the model, put forward assumptions again and again, and overthrow their own assumptions again and again.
Once, Watson was tinkering with the model according to his own ideas. He moved bases to look for various pairing possibilities. Suddenly, he found that the gland-thymine pair connected by two hydrogen bonds had the same shape as the guanine-cytosine pair connected by three hydrogen bonds, so his spirit was greatly uplifted. Because the mystery of why the number of songs of purine is exactly the same as that of pyrimidine is about to be solved. Chagaff's law suddenly became the inevitable result of DNA double helix structure. Therefore, it is not difficult to imagine how to use one strand as a template to synthesize another strand with complementary base sequences. Then, the skeletons of the two chains must be in opposite directions.
After intense and continuous work by Watson and Crick, the DNA metal model was quickly assembled. From this model, we can see that DNA is composed of two nucleotide chains, which are intertwined in opposite directions along the central axis, much like a spiral staircase. The armrests on both sides are the skeleton of alternating combination of sugar and phosphorus genes of two polynucleotide chains, and the pedals are base pairs. Due to the lack of accurate X-ray data, they dare not conclude that this model is completely correct.
The next scientific method is to carefully compare the diffraction pattern predicted by this model with the experimental data of X-ray. They called Wilkins again. In less than two days, Wilkins and Franklin confirmed the correctness of the double helix structure model with the analysis of X-ray data, and wrote two experimental reports, which were published in the British journal Nature. 1962, Watson, Crick and Wilkins won the Nobel Prize in Medicine and Physiology, while Franklin died of cancer in 1958, and did not win the prize.
After the discovery of DNA double helix structure, it greatly shocked the academic circles and inspired people's thoughts. Since then, people have immediately carried out a lot of molecular biology research centered on genetics. Firstly, an experimental study was carried out on how to arrange and combine four bases to encode and express 20 amino acids. 1967, the genetic code was completely cracked, and the gene got a new concept at the molecular level of DNA. It shows that gene is actually a fragment of DNA macromolecule, and it is the functional unit and structural unit of genetic material that controls biological traits. Many nucleotides in this unit fragment are not randomly arranged, but arranged in a meaningful password order. A certain structure of DNA can control the synthesis of protein of the corresponding structure. Protein is an important component of organisms, and the characteristics of organisms are mainly reflected by protein. Therefore, the control of genes on traits is realized by DNA controlling the synthesis of protein. On this basis, genetic engineering, enzyme engineering, fermentation engineering, protein engineering and so on have appeared one after another. The development of these biotechnology will surely make people use biological laws to benefit mankind. With the development of modern biology, it is becoming more and more obvious that it will become a leading discipline.
This article is taken from Creating 1000 Invention Cases, Guangxi Normal University Press, July 5438+0, 2006.
How was this jade discovered? Now only stories can be traced back.
A more reliable statement was discovered by the Burmese themselves, because the name of Meng Gong, a small town near its birthplace, means Drum City. It is said that a drum-shaped aquamarine was found here, which should be jade.
How the black hole was discovered is invisible and intangible. Astronomers mainly explore black holes through powerful X-ray sources. Although the black hole itself cannot emit any light, its great attraction to surrounding objects and celestial bodies still exists. When the surrounding matter is attracted by its strong gravity and gradually falls to the black hole, it will emit powerful X-rays and form an X-ray source in the sky. By searching and observing X-ray sources, people can find traces of black holes.
How were electrons discovered? Electrons are one of the basic particles that make up atoms. They are extremely small in mass and have a unit negative charge. Different atoms have different numbers of electrons. For example, each carbon atom contains 6 electrons and each oxygen atom contains 8 electrons. Those with high energy are farther away from the nucleus and those with low energy are closer to the nucleus. The movement of electrons in regions with different distances from the nucleus is usually called the layered arrangement of electrons.
As early as 188 1, Joseph Thomson of Cavendish Laboratory of Cambridge University discovered electrons. He proposed that any charge consists of elementary charge, and named the smallest unit of charge as an electron. The actual electron was discovered by British physicist Tang Musun in 1897. When he observed the deflection of cathode ray under the action of magnetic field and electrostatic field and measured the specific charge of particles and hydrogen ions in cathode ray (the ratio of particle charge to particle mass), he found that the specific charge of cathode ray particles was more than 1000 times larger than that of hydrogen ions. Because they have the same charge, Tang Musun concluded that cathode ray particles are much lighter than the lightest atom-hydrogen atom. Later, this particle was officially named electron. The discovery of electrons broke the traditional concept that atoms are the smallest inseparable material units. Because electrons come from atoms, it means that atoms have internal structures. With the deepening of electronic research, many important concepts of quantum theory have sprouted. For example, the discovery of electronic volatility proves that the matter wave hypothesis is correct; The prediction of positron existence leads to important concepts such as antiparticle and antimatter. Dirac first predicted the existence of positrons in theory. 1932, American Anderson first discovered positrons in cosmic ray experiments. Positron is the antiparticle of electron, which is represented by e+. It carries the same charge as the electron, but the sign is opposite and the mass is the same as the electron. The application of electronics The motive force of the development of science and technology in the 20th century largely comes from the application of electronics. Radio electronics, microelectronics, sub-micron electron beam processing technology, electron tubes, electronic computers, electron microscopes, electron-positron colliders and other disciplines and instruments with the word electron are all milestones in the history of modern science and technology development. In other instruments and devices, such as large-scale integrated circuits, picture tubes, transistors, etc. Electronic plays the leading role, although there is no electronic in the name. In the final analysis, an electronic device in the shape of * * * has two functions, one is how to generate electrons, and the other is how to control electrons. Electrons are usually produced by an electron gun, which generally consists of a heated heating wire (such as tungsten wire), a cathode coated with metal sheet and an anode with high voltage. These coated metal plates (such as nickel plates coated with a mixture of barium oxide and strontium oxide) will emit a large number of electrons when heated. If these electrons are attracted by a positively charged anode, they will form an electron flow. Electrons are subjected to electric field force in an electric field, and moving electrons are subjected to magnetic field force in a magnetic field. Using electric and magnetic fields, the movement of electrons can be controlled as needed, thus making various electronic devices. An electron gun in a TV picture tube can emit an electron beam. Adding some electromagnetic deflection devices between the electron gun and the screen can control the electron beam to hit the designated point on the screen and make the phosphor glow. Let the electron beam scan on the screen at high speed, so that the screen can display images.
Electrons are the first basic particles with unit negative charge discovered by people. Thomson, a British physicist, was the first person to prove the existence of electrons by experiments in 1897.
Thomson is an accomplished physicist. He became a member of the Royal Society at the age of 28 and served as the director of the famous Cavendish laboratory.
The discovery of X-rays, especially its ability to penetrate biological tissues and display images of their bones, has greatly encouraged researchers in Cavendish Laboratory in Britain. Thomson is inclined to crookes's view that it is a charged atom.
What is the cathode ray that causes X-rays? There was a heated debate between German and British physicists. German physicist Hertz declared in 1892 that cathode rays can't be particles, but only an etheric wave. All German physicists agree with this view, but the British physicist, represented by crookes, insists that cathode ray is a stream of charged particles, and Thomson, who is extremely quick-thinking, immediately plunged into this debate about the nature of cathode ray.
1895, French young physicist Perrin talked about the experiment of measuring cathode ray electricity in his doctoral thesis. He made negative rays enter the space in the cathode through a small hole and hit the Faraday tube to collect charge, and the electrometer showed negative charge; When the cathode ray tube is placed between the magnetic poles, the cathode ray deflects and cannot enter the small hole, and the electricity on the current collector disappears immediately, which proves that the charge is carried by the cathode ray. Perrin clearly expressed his support for the view that cathode rays are negatively charged particles through his experimental results, but at that time he thought that such particles were gas ions. In this regard, the German physicist who insisted that the cathode ray was an etheric wave immediately retorted that even if the cathode ray emitted negatively charged particles, the evidence consistent with the path of the cathode ray was not sufficient, so the charge displayed by the electrometer was not necessarily introduced by the cathode ray.
For Perrin's experiment, Thomson also thought that this left a loophole for Taitai, so he specially designed a clever experimental device and redone Perrin's experiment. He put two coaxial cylinders in a glass bulb connected with a discharge tube, and there was a gap between the two cylinders. Cathode rays from cathode A enter bubbles through the gap of the neck metal plug; The metal plug is connected with the cathode B. In this way, the cathode ray will not fall on the cylinder unless it is deflected by the magnet. The outer cylinder is grounded and the inner cylinder is connected with an electroscope. When the cathode ray does not fall in the gap, the charge sent to the electroscope is very small; When the cathode ray is deflected by the magnetic field and falls on the gap, a large amount of charge is sent to the electroscope. The amount of charge is amazing: sometimes the negative charge passing through the gap in one second is enough to change the potential of the 1.5 microfarad capacitor by 20 volts. If the cathode ray is deflected beyond the gap of the cylinder by the magnetic field, the charge entering the cylinder will reduce its value to only a small part when it hits the target. Therefore, this experiment shows that no matter how to distort and deflect cathode rays by magnetic field, negatively charged particles are inextricably linked with cathode rays. This experiment proves that cathode rays and negatively charged particles follow the same path under the action of magnetic field, and that cathode rays are composed of negatively charged particles, thus ending this debate and laying the foundation for the discovery of electrons.
How to successfully deflect cathode rays under the action of electric field? As early as 1893, Hertz made this attempt, but it failed. Thomson believes that Hertz's failure mainly lies in the low vacuum degree, which leads to the ionization of residual gas and the establishment of electrostatic field. Therefore, Thomson adopted the cathode ray tube device and achieved success by improving the vacuum degree of the discharge tube. Through this experiment and improving the vacuum degree of the discharge tube, Thomson not only made the cathode?
The discovery of electrons is related to the experimental study of cathode ray, which begins with the discharge phenomenon of vacuum tube. As early as 1858, German physicist Pique discovered cathode rays while studying gas discharge with discharge tubes. Pluck found with a vacuum pump that as the air in the glass tube became thinner to a certain extent, the discharge in the tube gradually disappeared. At this time, green fluorescence appeared on the glass tube wall opposite to the cathode. When the magnetic field applied outside the tube changes, the position of fluorescence will also change. It can be seen that this fluorescence is produced by the radiation emitted by the cathode hitting the glass tube wall.
What exactly is cathode ray? /kloc-in the last 30 years of the 0/9th century, many physicists devoted themselves to research. At that time, British physicist crookes and others had proposed that cathode rays were negatively charged particles according to the fact that cathode rays were deflected in the magnetic field. According to the deflection, the charge-to-mass ratio (E/M) of cathode ray particles is 1000 times larger than that of hydrogen ions. At that time, Hertz and his student Leonard added an electric field perpendicular to the cathode ray tube, trying to observe its deflection in the electric field, so they thought the cathode ray was uncharged. In fact, because the vacuum degree is not high, the electrostatic field cannot be established.
J·J· Thomson has designed a new cathode ray tube (figure 1). Under the action of electric field, the cathode ray emitted by cathode C passes through the electric field between another pair of electrodes D and E after focusing by α and B, and a transverse deflection scale is attached to the right tube wall. He repeated Hertz's electric field deflection experiment and didn't see any deflection at first. However, he analyzed that the reason why there was no deflection may be that the electric field could not be established. So, he used the most advanced vacuum technology at that time to obtain a high vacuum, and finally made the cathode ray deflect stably in the electric field, which clearly showed that the cathode ray was negatively charged. He also applied a magnetic field perpendicular to the electric field and the ray velocity (this magnetic field was generated by the coil outside the tube). When the electric field force eE is equal to the Lorentz force evB of the magnetic field, the ray can hit the center of the pipe wall without deflection. According to the calculation, the charge-mass ratio of cathode ray particles is e/m ≈ 10 1C/kg. Through further experiments, Thomson found that by using different materials or changing the gas type in the tube, the charge-to-mass ratio E/M of radiation particles remained unchanged. It can be seen that this kind of particle is a common component in various materials.
1898, Thomson and his students continued to do research on directly measuring the charge of charged particles. One time, the electronic charge of1.1x10-19c was measured by Wilson cloud chamber, which proved that the mass of electrons is about one thousandth of that of hydrogen ions. Thomson finally solved the mystery of cathode ray. Later, many scientists measured the charge value of electrons more accurately, among which American scientist Millikan measured the charge value of electrons for the first time in 1906, e = L.34x 10- 19c. 19 13 finally measured e =1.59x10-19c. It was a high-precision measurement. Modern accurate electron charge E = 1.602 17733 (49
How X-rays were discovered wilhelm konrad rontgen, the discoverer of X-rays, was born in Nipp, Germany, on 1845. 1869 received a doctorate in philosophy from the University of Zurich. In the following nineteen years, Roentgen worked in a number of different universities and gradually gained a reputation as an excellent scientist. 1888 was appointed professor and director of the Institute of Physics of the University of Wü rzburg. Roentgen found X-rays at 1895.