Zernike (Zernike), Fritz( Nederlands physicist, Nobel Prize in Physics, 1953)
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Biography Zernike (Zernike), Fritz
July 16, 1888, Mr.. - March 10, 1966
Netherlands physicist Fritz Zernike born in g. Amsterdam was the second of six children of Charles Frederick Zernicke, director of elementary school mathematics teacher and author of several books on mathematics, and Antje (nee Dipernik) Zernike, also a teacher of mathematics. As a boy he loved to experiment in his home laboratory and rejoiced, thinking hard math problem. In high school, resplendent in physics, he was rather indifferent to other subjects.
In 1905, Mr.. C. enrolled in the University of Amsterdam, where he specialized in chemistry and as neprofiliruyuschih subjects studied physics and mathematics. Three years later he took part in the contest works, funded by the University of Groningen, and was awarded a gold medal for his work on probability theory. The same award he received from the Dutch Scientific Society in 1912. for the problem of light scattering by the pure substances and mixtures. An expanded version of this work was his dissertation, for which the University of Amsterdam in 1915. he was awarded a doctoral degree.
In the same year, Ts, which is already considered a leading expert in his field, was replaced by L. With Ernsteyna to post a lecturer in physics at the University of Groningen, where two years earlier known astronomer YA.K. Kaptein made C. his assistant. By 1920, when he became a full professor of theoretical physics, C. and Ernsteyn conducted a joint study on statistical mechanics that has received wide recognition for the significant contribution it has made in this area. C. also used their mathematical abilities and skills in the manufacture and improvement of scientific instruments such as a galvanometer, but after 1930. major efforts he had sent to study in the field of optics.
At first it was interested in the effect of slit diffraction gratings. Diffraction grating is a transparent glass or a mirror, on the surface of which suffered a large number of thin, closely spaced, equally spaced grooves. The grooves divide passing or reflected light on many individual sources scheleobraznyh. When light rays from a variety of sources (normally focused lens) reach a certain point on the screen, the brightness is the result of summation of all rays. Since light is an electromagnetic wave, . consisting of electric and magnetic fields, . oscillated, . beams are added or subtracted depending on, . They arrive at a given point in the same or opposite phases,
. Phase is a definite position in the process of vibration, and when the light beam passes a distance equal to the wavelength, then for this time variation makes a complete cycle (returns to the initial phase). As the rays from different parts of the slit source on the grid, as well as the rays from the different slits are different distance from a given point on the screen They come in different phases. If the light is monochromatic (single wavelength), then the result is a pattern consisting of narrow strips or lines, alternately light (the rays come in the same phases) and dark (when the rays come in conflict with each other). If the light is a mixture of different wavelengths (colors for visible light), each wavelength gives its diffraction pattern is different from the rest. The result is a continuous spectrum of individual colors like a rainbow.
. Many scholars have noticed that the lattice that contain duplicate errors in the arrangement of the grooves caused by malfunctions in the mechanism to deliver these grooves, generate extra lines, called phantoms, with each party released a bright line
. They considered these lines are not worthy of attention and gave them the appearance of different explanations, with whom T. could not agree. Assuming, . ghosts that arise from the phase shifts, . caused by an error of lattices, . He made a series of experiments, . not only proved him right, . but also led to his invention of the device, . he named a phase-contrast microscope.,
. Optical microscopes have been brought to a high degree of perfection of the German optical company
. However, the opportunity to see the enlarged detail depended on their ability to pass or reflect a certain portion of light is very different from the overall light environment. When working with relatively transparent drugs, as often happens in medicine and biology, conventional microscopes have a number of serious defects. C. believed that the light passing through the transparent parts in the specimens, differs from the light that passes by them, and, therefore, contains the necessary information. The difference here is not in amplitude, which can detect the eye, and in phase, which the eye is unable to distinguish. Phase is different because light travels at different speeds in different substances. If the substance is transparent, . it does not change the amount of transmitted light, . but changes the number of wavelengths or fractions of wavelengths, . falling on the entire length of the optical path, . because it lowers the speed of light and, . hence, . distance, . traversed in one period of oscillation,
. Usually they say that it leads to a lag phase. C. in their experiments with the ghosts of diffraction gratings have found a method of converting the phase changes in the amplitude, which allows him to make clear the details visible to the eye.
. The principle consisted in, . to impose a light, . passing through a transparent object, . on the homogeneous background lighting, . representing a small portion of direct light (light, . flowing object), . who knowingly possesses ahead in phase by a quarter wavelength,
. As a result of a combination of light passing through a transparent object, which has a lag in phase relative to direct light from the background lighting, which has a phase advance, formed by destructive interference, ie. decrease brightness. For the observer's eye it looks as if the object absorbs light. C. sought to correct background lighting, placing what he called a phase plate (glass plate engraved with the notch), the beam of light in the focal plane of the objective lens in the microscope.
Phase-contrast microscope Y. made possible the observation of colorless organisms such as cells or bacteria without the use of dyes, which are often killed samples. It allows for more accurate observations than those that could be obtained with dark-field illumination - another method often led to incorrect interpretation of small details. Phase-contrast method was also useful in evaluating the roughness of optical surfaces, such as a telescope mirror, and diffraction gratings themselves, who gave birth to the idea itself.
. First time making sure that the immensity of his invention and understand its importance, C
. devoted to his Germanic company 'Zeiss' in Jena, a leading manufacturer of microscopes at a time. But company representatives did not show due interest in him. 'They said that if it had practical value, they would have invented it themselves', - recalled Ts
During the Second World War, in 1940, the Germans troops occupied the Netherlands. In search of inventions that could be useful in military affairs, the German military authorities met with a description of the Y. by phase-contrast microscope, and in 1941. first tools were made. However, only after the war, this technology has been used in full.
Phase-contrast microscope has become an extremely important tool, particularly in medical research. As a visiting professor of physics at Johns Hopkins University in Baltimore in 1948 ... 1949. C. continued to improve his invention and was able to obtain color images.
In 1953, Mr.. C. was awarded the Nobel Prize in Physics "for support of a phase-contrast method, especially for the invention of a phase-contrast microscope '. 'When the Nobel Prize awarded for contribution to classical physics, . - Said Eric Hultц╘n, . Member of the Royal Swedish Academy of Sciences, . introducing winner, . - That this very fact is so unique, . that the search for analogues we have to go back to the very first Nobel Prize ', . because, . few exceptions, . all subsequent premiums were awarded "for discoveries in the field of atomic and nuclear physics.",
. In 1930
. C. Theodore married Wilhelmina van Bommel Van Fleet, who had a daughter from his first marriage, they had one son. Wife C. died in 1945, and in 1954. He married Lena Baanders. They had no children. In 1958, Mr.. after more than 40 years of teaching and research activities of C. resigned from the University of Groningen and settled in the town of Naarden near Amsterdam. Before his death he had Parkinson's disease progressed.
While recognition has come to the Y. later, he received many awards, in addition to the Nobel Prize, including the Rumford Medal of the Royal Society of London (1952) and an honorary degree from the University of Amsterdam, London, Poitiers and Modena. He was elected a member of the Royal Netherlands Academy of Sciences in 1946