Measurement of the energy of pulses of optical radiation over a wide range of durations and repetition frequencies

1981 ◽  
Vol 24 (3) ◽  
pp. 195-198
Author(s):  
V. T. Kibovskii ◽  
F. Kh. Klychev ◽  
V. I. Kukhtevich ◽  
Sh. A. Rubin
Keyword(s):  
2019 ◽  
Vol 86 (12) ◽  
pp. 758
Author(s):  
E. V. Kuvaldin ◽  
A. A. Shulga

2020 ◽  
Vol 21 (4) ◽  
pp. 779-784
Author(s):  
G.I. Barylo ◽  
M.S. Ivakh ◽  
Z.M. Mykytiuk ◽  
I.P. Kremer

The work is devoted to the development of medical systems for monitoring biomedical indicators. The problem of developing a universal hardware software-controlled control system for the diagnosis of biological objects is solved. The main requirements for such a system are a wide range of functionality for combining different methods of measurement transformation and compliance with modern trends in the development of microelectronic sensors. Given the requirements for modern microcircuitry, in particular for sensing devices of the Internet of Things, the signal path of the sensors is implemented on the basis of PSoC family 5LP Family Cypress. Approbation of the developed system is carried out in the course of research of the character of optical radiation in the course of measurement of biomedical indicators.


2018 ◽  
pp. 38-47
Author(s):  
Leonid B. Prikupets ◽  
George V. Boos ◽  
Vladislav G. Terekhov ◽  
Ivan G. Tarakanov

Results of the first photobiological studies of optimisation of LED phyto irradiators spectrum and irradiance level, when growing salad­greengrocers plants in greenhouses and plant factories in photoculture conditions, are presented in the article. The results are given as a series of producing capacity curves for salad and basil plants when irradiating by quasi­monochromatic spectrum for three PAR ranges: blue, green and red. In the experiment, levels of photosynthetic photon irradiance (70 ? 230) µmol/s·m2 and of irradiance (13 ? 60) W/m2 were varied within a wide range. “Rough” spectra of optical radiation action estimated over producing capacity of plants with different irradiance levels are given, and questions of additivity of different spectral radiation influence in forming vegetable biomass are considered. Evaluations of efficiency of various PAR intervals for synthesis of biochemical combinations determining nutrition facts of the studied cultures are performed.


Author(s):  
Maryna Asayonak ◽  
Andrey Zenevich ◽  
Yauhen Novikau

Currently, in many applications, photodetectors are needed that provide registration of optical radiation in a wide range of intensities and allow combining two operating modes: current mode and photon counting. These devices include silicon photoelectronic multipliers (SiPM), which have a number of advantages compared to electrovacuum photomultipliers and avalanche photodetectors. However, the influence on the photoresponse characteristics of SiPM of such important factors as the supply voltage and temperature has not been studied enough. The influence of these factors on the amplitude parameters of the photoresponse of SiPM is studied. The block diagram of the experimental setup is presented, with the help of which the photoresponse characteristics of SiPM with n+-n-p+ and p+-p-n+ structures manufactured by Integral OJSC (Republic of Belarus) were measured. The dependences of the average amplitude of the photoresponse on the supply voltage and temperature of silicon photomultipliers for various wave-lengths of optical radiation are presented. It was found that when SiPM were exposed to optical pulses with the same duration and energy exposure at the same temperature at the same overvoltage, the photoresponse amplitude was larger for a SiPMr with p+-p-n+ structure regardless of the wave-length of optical radiation. It was found that, when the overvoltage changes, the increase in the photoresponse amplitude is observed only in the overvoltage range ΔU = 0 ¸ 3 V for all the studied SiPM, irrespective of the wave-length of the detected optical radiation and temperature. It was determined that a decrease in temperature led to an increase in the amplitude of the photoresponse pulses. The temperature dependence of the amplitude of the photoresponse was most pronounced for SiPM with the p+-p-n+ structure. It was shown that the dependences of the average amplitude of the photomonitor Si-PM on the energy exposure have a linear section, the length of which depends on the wavelength of the detected optical radiation.


Author(s):  
R.W. Horne

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.


Author(s):  
E.D. Wolf

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.


Author(s):  
B. J. Hockey

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.


Author(s):  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda

It is interesting to observe polymers at atomic size resolution. Some works have been reported for thorium pyromellitate by using a STEM (1), or a CTEM (2,3). The results showed that this polymer forms a chain in which thorium atoms are arranged. However, the distance between adjacent thorium atoms varies over a wide range (0.4-1.3nm) according to the different authors.The present authors have also observed thorium pyromellitate specimens by means of a field emission STEM, described in reference 4. The specimen was prepared by placing a drop of thorium pyromellitate in 10-3 CH3OH solution onto an amorphous carbon film about 2nm thick. The dark field image is shown in Fig. 1A. Thorium atoms are clearly observed as regular atom rows having a spacing of 0.85nm. This lattice gradually deteriorated by successive observations. The image changed to granular structures, as shown in Fig. 1B, which was taken after four scanning frames.


Author(s):  
T. Miyokawa ◽  
S. Norioka ◽  
S. Goto

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.


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