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11.
A new switched-capacitor floating inductance simulation circuit which does not depend on matching of passive elements is presented. A switched-capacitor source termination circuit which functions as a sample-and-hold circuit for a filter is also described. 相似文献
12.
Sobolev N. A. Aleksandrov O. V. Sakharov V. I. Serenkov I. T. Shek E. I. Kalyadin A. E. Parshin E. O. Melesov N. S. 《Semiconductors》2019,53(2):153-155
Semiconductors - The implantation of Czochralski-grown p-type silicon with 1-MeV germanium ions at a dose of 2.5 × 1014 cm–2 does not lead to the amorphization of single-crystal... 相似文献
13.
Kalyadin A. E. Shtel’makh K. F. Aruev P. N. Zabrodskii V. V. Karabeshkin K. V. Shek E. I. Sobolev N. A. 《Semiconductors》2020,54(6):687-690
Semiconductors - Silicon light-emitting diodes with luminescence associated with (113) defects are fabricated by the implantation of 350-keV oxygen ions at a dose of 3.7 × 1014 cm–2 and... 相似文献
14.
This review focuses on the response of "stress" hormones to heat, exercise (single or repeated bouts), and combinations of these stimuli, with particular reference to their impact upon immune function. Very hot conditions induce a typical stress response, with secretion of catecholamines and cortisol. The catecholamines induce a demargination of leukocytes, and cortisol subsequently causes cells to migrate to lymphoid tissue. Sustained exercise, even in a thermally comfortable environment, induces a larger hormonal response than moderate thermal stress. With moderate exercise, increases in leukocyte numbers are related mainly to plasma norepinephrine concentrations, but with more intense exercise epinephrine concentrations assume a major importance. As exercise continues, plasma cortisol levels also rise, inducing an influx of neutrophils from bone marrow and an efflux of other leukocyte subsets. A combination of exercise and heat stress augments both hormonal and leukocyte responses. But these changes seem to be reversed if temperatures are clamped by exercising in cold water. If a second bout of exercise is performed with an inter-test interval of 30-45 min, neither hormone concentrations nor immune responses show any great cumulative effect under temperate conditions. However, in a hot environment the second exercise bout induces a larger and more persistent neutrophilia. Training influences these various responses mainly by decreasing the stress imposed when exercising at a given absolute work-rate. 相似文献
15.
We prepared interpenetrating polymer networks (IPNs) composed of a gelatin hydrogel and a HydroThaneTM elastomer to combine the advantages of both polymers into one biomaterial. Fourier transform Infrared (FTIR) spectroscopy
and Differential Scanning Calorimetry (DSC) confirmed the co-existence of the two polymers in the IPNs. Optical light microscopy
confirmed hydrogel domains were interspaced into an elastomer network. Hydration and stability studies in aqueous solution
showed that, although the IPN biomaterials exhibited stable swelling for more than 30 days, approximately 10% and 50% loss
of the hydrogel component were confirmed at room temperature and 37 °C, respectively, using gel permeation chromatography
(GPC). The swelling study in the serum-containing medium indicated the biomaterials maintained their swelling stability for
different periods, depending on the extent of gelatin methacrylation, photoinitiator concentration and incubation temperature.
Lastly, the biomaterials exhibited higher failure stress and lower failure strain in a dry state than in a swollen state,
and showed limited changes in both stress and strain at room temperature and at 37 °C, in contrast with a decrease at 50 °C.
No significant effects of gelatin methacrylation on mechanical properties were noticed. The preparation and characterization
methods were well established and formed the basis of further developing the biomaterials. 相似文献
16.
Feng Ming-Hsiang; Chan Shek Ling; Xiang Yuefang; Huber Carol P.; Lim Carmay 《Protein engineering, design & selection : PEDS》1996,9(11):977-986
Two binding modes of the isobutyl-NH-Eps-Leu-Pro inhibitor tocathepsin B have been proposed. Molecular docking using an empiricalforce field was carried out to distinguish between the two modes.The search began with manual docking, followed by random perturbationsof the docking conformation and cycles of Monte Carlo minimization.Finally, molecular dynamics was carried out for the most favorabledocking conformations. The present calculations predict thatthe isobutyl-NH-Eps-Leu-Pro inhibitor preferentially binds tothe S' rather than the S subsites of cathepsin B. The S' bindingmode prediction is supported by the X-ray crystal structureof cathepsin B bound to a closely related ethyl-O-Eps-Ile-Proinhibitor, which was found to bind in the S' subsite with theC-terminal epoxy ring carbon making a covalent bond to the sulfuratom of Cys29. This agreement, in turn, validates our dockingstrategy. Furthermore, the calculations provide evidence thatthe dominant contribution to the total stabilization energyof the enzymeinhibitor complex stems from the strongelectrostatic interaction between the negatively charged C-terminalcarboxylate group of the ligand and the positively charged imidazoliumrings of His110 and His111. The latter are stabilized and heldin an optimal orientation for interactions with the C-terminalend of the ligand through a salt bridge between the side chainsof His110 and Asp22. By comparison with the crystal structure,some insight into the specificity of the epoxyldipeptide familytowards cathepsin B inhibition has been extracted. Both thecharacteristics of the enzyme (e.g. subsite size and hydrophobicity)as well as the nature of the inhibitor influence the selectivityof an inhibitor towards an enzyme. 相似文献
17.
Yanbin Jiang Guoyi Tang Chanhung ShekWei Liu 《Journal of Alloys and Compounds》2011,509(11):4308-4313
The effect of electropulsing treatment (EPT) on the microstructure and texture evolution of the cold-rolled AZ91 magnesium alloy strip was investigated using X-ray diffraction (XRD) and electron backscattered diffraction patterns (EBSD). The results indicated that EPT accelerated tremendously the recrystallization behaviour of the cold-rolled AZ91 magnesium alloy strip at a relatively low temperature within a short time of 7 s. It also suppressed precipitation of β-Mg17Al12 phase, compared with conventional heat treatment. The recrystallized grains favourably weakened the intensity of the basal texture. A mechanism for rapid recrystallization process during EPT was proposed based on the enhancement of nucleation rate and atomic diffusion resulting from the coupling of the themal and athermal effects. 相似文献
18.
The transformation characteristics of ferrite transformation in a cast of specially designed duplex stainless steel have been studied. The ferrite content in the duplex stainless steel was found to settle to steady values after long-term exposure to high temperatures. This feature can be used for developing an average temperature indicator that is very easy to use and requires only very simple equipment. 相似文献
19.
20.
C.E. Coleman S. Sagat G.K. Shek D.B. Graham M.A. Durand 《International Journal of Pressure Vessels and Piping》1990,43(1-3):187-204
A few Zr-2·5 Nb alloy pressure tubes in CANDU nuclear reactors have leaked through cracks that have grown by delayed hydride cracking (DHC). In some instances, tubes contained confirmed leaks that were leaking at a rate too low for precise identification of the leaking channel. Controlled stimulation of DHC can be used to help locate these leaks by extending the crack and increasing the leak rate without approaching crack instability. In the event of a leak being detected, a plant operator can gain time for leak location by a heating and unloading manoeuvre that will arrest crack growth and increase the critical crack length. This manoeuvre increases the safety margin against tube rupture. If required, the operator can then stimulate cracking in a controlled manner to aid in leak identification. Sequences of temperature and load manoeuvres for safe crack stimulation have been found by laboratory tests on dry specimens and the efficacy of the process has been demonstrated, partly in a power reactor, and partly in a full-scale simulation of a leaking pressure tube. 相似文献