scholarly journals X-Rays in Physical Science

Nature ◽  
1919 ◽  
Vol 104 (2610) ◽  
pp. 235-237
Author(s):  
W. H. BRAGG
Keyword(s):  
Physical Science ◽  
X Rays

scholarly journals The Professor G. De-Metz’s Contribution to the Development of Physical Science in Ukraine

2021 ◽  
Vol 66 (9) ◽  
pp. 819
Author(s):  
M.V. Gutnyk ◽  
E.E. Tverytnykova
Keyword(s):  
Physical Science ◽  
Historical Review ◽  
Scientific Work ◽  
Botanical Garden ◽  
Physical Factors ◽  
X Rays ◽  
Major Work ◽  
Master's Thesis ◽  
Kyiv Polytechnic Institute ◽  
Teaching Physics

The contribution of Professor Georgy De-Metz to the development of physical science in Ukraine is highlighted. The information about the childhood of the future scientist is given and his formation as a scientist is shown. He was extensively involved in physics under the guidance of F. Shvedov and M. Umov. The head of his master’s thesis was Professor A. Kundt. After the publication of the discovery of X-rays by Roentgen, G. De-Metz not only repeated the experiments of the German colleague, but also put new ones. In particular, he investigated the influence of various physical factors on obtaining the clear photographs of this radiation. The scientist managed to make clear pictures of frogs with an image of the internal organs. He also explored the possibility of using X-rays in medicine. In the early twentieth century, he published his first major work on radioactivity “Doctrine of the radioactivity and radioactive substances”, in which the scientist described the physical basics of radioactivity in detail. The researcher examined the radium content in water and flora from the pond of the Kyiv Botanical garden. Using the results of the studies G. De-Metz concluded that some types of living tissue were able to absorb and even concentrate radium from water and the environment. In his work “Radioactivity and the structure of matter,” not only a historical review of the development of the doctrine of radioactivity was made, but also the new experimental works of the author were represented. He analyzed 68 various minerals of uranium. G. De-Metz described the picture of the geographical distribution of radioactive minerals and identified the richest deposits of uranium ore at that time. In addition to his scientific work, the scientist was a well-known methodist. It was he who, in the 1920s, developed a method of teaching physics in institutes of Ukraine. It is reported that the scientist in a different period of time was the head of the physical department at various institutions of higher education. Moreover, he was even the Rector of the St. Volodymyr University, Kyiv Polytechnic Institute, and Kuban University.

STUDIO DI UNA LENTE PER CANNOCCHIALE DI GRANDI DIMENSIONI LAVORATA DA EVANGELISTA TORRICELLI

Nuncius ◽  
1996 ◽  
pp. 123-134
Author(s):  
E. SCHETTINO ◽  
G. PATERNOSTER, ◽  
R. RINZIVILLO,
Keyword(s):  
Physical Science ◽  
The Other ◽  
X Rays ◽  
Scientific Instruments ◽  
Large Telescope ◽  
Xviii Century ◽  
The University

Abstracttitle SUMMARY /title The Museum of the Department of Physical Science at the University of Naples holds a large telescope lens, work of Evangelista Torricelli. This lens which probably reached Naples in the first half of XVIII Century was forgotten until it was catalogued and placed with the other scientific instruments in the museum in 1984. The authors update the optic measure of the Torricelli lens taken by Gilberto Govi in 1886 and determine the composition of the lens glass by the fluorescence revealed from X-rays. On the basis of an analysis of correspondence by Torricelli they conclude that this is one of the two lenses which the scientist wrote to the gesuit Raffaello Prodanelli from Rome on October 14, 1645.

X-Rays in Physical Science

1920 ◽  
Vol 16 (62) ◽  
pp. 24-25
Author(s):  
W. H. Bragg
Keyword(s):  
Physical Science ◽  
X Rays

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

The Clinical, Roentgenological and Morphological Effects of an Acute Exposure of Phosgene on the Lungs of Dogs

1971 ◽  
Vol 29 ◽  
pp. 236-237
Author(s):  
R. F. Bils ◽  
W. F. Diller ◽  
F. Huth
Keyword(s):  
Latent Period ◽  
Chemical Industry ◽  
Toxic Substance ◽  
Lung Edema ◽  
X Rays ◽  
Beagle Dogs ◽  
Male And Female ◽  
Morphological Alterations ◽  
Before And After ◽  
Electron Microscopes

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.

Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

1974 ◽  
Vol 32 ◽  
pp. 570-571
Author(s):  
R. H. Duff
Keyword(s):  
Species Identification ◽  
Valence Electron ◽  
Chemical Species ◽  
X Rays ◽  
Chemical Bonds ◽  
Small Shift ◽  
X Ray ◽  
Electron Transitions ◽  
Peak Energy ◽  
Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

Structural preservation and absolute contrast of catalase crystal sections prepared with tannic acid

1983 ◽  
Vol 41 ◽  
pp. 448-449
Author(s):  
C.W. Akey ◽  
M. Szalay ◽  
S.J. Edelstein
Keyword(s):  
Tannic Acid ◽  
Beef Heart ◽  
X Rays ◽  
Screw Axis ◽  
General Applicability ◽  
Thin Sections ◽  
Beef Liver ◽  
3 Dimensional ◽  
Dimensional Reconstruction ◽  
Structural Preservation

Three methods of obtaining 20 Å resolution in sectioned protein crystals have recently been described. They include tannic acid fixation, low temperature embedding and grid sectioning. To be useful for 3-dimensional reconstruction thin sections must possess suitable resolution, structural fidelity and a known contrast. Tannic acid fixation appears to satisfy the above criteria based on studies of crystals of Pseudomonas cytochrome oxidase, orthorhombic beef liver catalase and beef heart F1-ATPase. In order to develop methods with general applicability, we have concentrated our efforts on a trigonal modification of catalase which routinely demonstrated a resolution of 40 Å. The catalase system is particularly useful since a comparison with the structure recently solved with x-rays will permit evaluation of the accuracy of 3-D reconstructions of sectioned crystals.Initially, we re-evaluated the packing of trigonal catalase crystals studied by Longley. Images of the (001) plane are of particular interest since they give a projection down the 31-screw axis in space group P3121. Images obtained by the method of Longley or by tannic acid fixation are negatively contrasted since control experiments with orthorhombic catalase plates yield negatively stained specimens with conditions used for the larger trigonal crystals.

Diagnosis of Silica Induced Granulomatous Hypersensitivity

1982 ◽  
Vol 40 ◽  
pp. 336-337
Author(s):  
C. W. Mehard ◽  
W. L. Epstein
Keyword(s):  
Electron Microscope ◽  
White Female ◽  
X Rays ◽  
Blood Tests ◽  
Analytical Electron ◽  
Analytical Electron Microscope

The underlying cause of a disease may not he readily apparent but may have a long history in development. We report one such case which was diagnosed with the aid of the analytical electron microscope.The patient, a 48 yr. old white female, developed a tender nodule on the sole of her foot in December, 1981. Subsequently additional lesions developed on the same foot resulting in deep pain and tenderness. Superficial lesions also extended up to the knee on both legs. No abnormalities were revealed in blood tests or chest X-rays.

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