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1.
S. Brabetz R. Weidl F. Klemm L. Dörrer F. Schmidl P. Seidel 《Journal of Low Temperature Physics》1997,106(3-4):527-532
We investigated different types of high-Tc DC-SQUID gradiometers with the aim to develop an one-channel heart monitoring system for non-invasive measurements in unshielded
environment. This system could be used to obtain information about the patients condition in serial examinations and in emergency
cases fast and stable. Step-edge and bicrystal Josephson junctions were used to prepare planar galvanically coupled thin film
gradiometers and magnetometers. These sensors were used to carry out measurements in well-shielded and non-shielded environment
and we compared the different noise properties and field gradient resolutions. With different types and sizes of high-Tc DC-SQUID sensors magnetocardiograms were measured in a magnetically shielded room. The influence of antenna configurations,
SQUID parameters, and cooling conditions on the measurement of magnetocardiograms will be discussed. We investigated possibilities
to suppress the earth magnetic field (with pairs of Helmholtz coils) and for noise field compensation in unshielded environment. 相似文献
2.
Agnieszka J. Klemm Piotr Klemm Kazimierz Rozniakowski Tomasz W. Wojtatowicz 《Building and Environment》2002,37(12):1233-1240
This paper presents the results of the larger study into a potential application of laser radiation for the detection of phase transition processes in low temperatures occurring on the surface layers of cementitious materials. An attempt was made to identify relationships between the environmental conditions—temperature and air humidity, and the selected parameters of the reflected light. Onset of the condensation process and formation of water microdrops on the surface of the material leads to the phase displacement of individual laser rays, which are represented by different speckle images.
Although the analysis of parameters of the reflected light are very difficult in the case of porous materials because of highly developed roughness of the surface structure it has been proved that a dynamic study of the phase transition phenomena can be successfully carried out without mechanical intervention. 相似文献
3.
Agnieszka J Klemm Piotr Klemm Kazimierz Rozniakowski Tomasz W Wojtatowicz 《Building and Environment》2002,37(12):1221-1232
This paper present the results of the investigation into a potential application of laser radiation for the detection of phase transition processes occurring on the surface layers of porous materials. An attempt was made to discuss in the approximation equations, the relationships between coefficients of the reflected light, the temperature and humidity of the surrounding environment. Laser light reflected from the porous surface carries information about the roughness of the structure. The presence of water microdrop on the surface of the porous material, as a result of condensation and thus a phase transition, leads to the phase displacement of individual rays, which is represented by different images. Therefore, a comprehensive analysis of the reflected light parameters allows a dynamic study of the phase transition phenomena without mechanical intervention. 相似文献
4.
5.
Photochromism of the o-Nitrobenzylpyridines in Supercooled Melts 2-(2′, 4′-dinitrobenzyl)-pyridines 1 a–g and 4-(2′,4′-dinitrobenzyl)-pyridine 2 form supercooled melts which are photochromic on u.v.-irradiation. The photochromism and the kinetic stability of the coloured form in supercooled melts are quite different from the behaviour in ethanolic solution. The differences are explained on the basis of a polymethin constitution of the coloured form. 相似文献
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The long-term high-temperature cyclic oxidation (100 cycles, 104 h, 1500°C) of a Si3 N4 material and a Si3 N4 /MoSi2 composite, both fabricated with Y2 O3 as a sintering additive, was studied. Both materials exhibited similar oxidation rates because of surface SiO2 formation described by an almost parabolic law and a total weight gain of 3–4 mg/cm2 after 104 h. As a consequence of oxidation processes in the bulk, microstructural damage was found in the Si3 N4 material. These effects were not observed in the composite. The remarkable microstructural stability observed offers the high potential of Si3 N4 /MoSi2 composites for long-term structural applications at elevated temperatures up to 1500°C. 相似文献
8.
The role of 4-hydroxynonenal (HNE), a major lipid peroxidation product, in oxidative damage to mitochondrial cytochrome c oxidase (COX) was examined. Oxidative stress was induced in mitochondria isolated from livers of male Sprague-Dawley rats by tert-butylhydroperoxide (t-BHP). COX activity was inhibited, with a concomitant increase in endogenous HNE level in mitochondria. COX activity was also inhibited following incubation of mitochondria with 50-450 microM HNE. Blocking HNE degradation intensified COX inhibition by HNE and by t-BHP-induced oxidative stress, the latter accompanied by a simultaneous increase in endogenous HNE production. On the other hand, COX inhibition by HNE was markedly reduced by potentiating HNE degradation via enhancing conjugation of HNE with reduced glutathione (GSH). Incubation of purified COX with 10-400 microM HNE resulted in HNE adduct formation with specific subunits of COX, correlated with inhibition of the enzyme activity. These data suggest that HNE may inhibit mitochondrial COX by forming adducts with the enzyme, and that this could be one mechanism underlying mitochondrial damage caused by oxidative stress. The findings also illustrate a role for GSH in protecting mitochondria from the deleterious effects of HNE. 相似文献
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10.
Methodical aspects relating to determination of serum-bactericidal capacities were studied, with the view to using them to test the bearing of abiotic environmental factors on defence mechanisms against infections. Communicated are methodical experience by which to enhance the methods used to higher accuracy as well as experience regarding biological variance in calf and results obtained from follow-up checks in which antigens were systematically used. Reference is made also to other methodical issues. The method actually used to determine serum-bactericidal capacity was found to be suitable for an assessment of reactivity of infection defence in calf for its good accuracy. Follow-up checks, using antigens, will enable better assessment of the action of abiotic environmental factors on the complex defence system of calf. 相似文献