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971.
972.
NMR Relaxation and Imaging have been applied to study preparation processes of ceramic porous samples. Relaxation analysis gives a clear characterization of the materials, with high sensitivity. Differences in the method of preparation and steps as low as 25 degrees C in the firing temperatures are well detectable. Furthermore, the images permit distinguishing the different samples. The effects of the contrast in relaxation times dominate those due to the different porosities of the samples. Scanning Electron Microscopy confirms the interpretation that the changes in relaxation times are due to different pore space structures associated with the different firing temperatures. The higher the firing temperature, the larger are the pores and the higher is the amount of compact, sintered matrix, leading to higher relaxation times.  相似文献   
973.
974.
The powder mixtures used for diffusion galvanizing (Zn + inert filler + activator) have the following deficiencies: susceptibility to sintering and fusing under elevated CTT temperatures, complexity of correcting the set of components in repeated use of the mixtures and the related instability of the results obtained, complexity of regeneration of worked-out mixtures, elevated ecological hazard of their use, etc. This explains the need for the present work, which shows that most of the mentioned deficiencies can be eliminated by an appropriate choice of the mixture components and (or) preliminary treatment of them.  相似文献   
975.
A multifunctional measurement system utilizing a noncontacting, thermal-tracer primary detector is described. It provides for the automatic acquisition of information on volumetric and mass flow rates and the properties of fluid flows.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 10–11, August, 1994.  相似文献   
976.
977.
 Thick film technology was used to manufacture a solid-state electrochemical nitrogen dioxide sensor. The prepared sensor has a linear dependence of electromotive force that is based in the NO2 concentration level. This paper presents discussion on a thick-film sensor that has a much smaller dimension and shorter response time as compared to typical ceramic solid-state electrochemical devices. Received: 26 February 1996/Accepted: 27 June 1996  相似文献   
978.
979.
During parasitization of Heliothis virescens, Campoletis sonorensis deposits an egg along with venom, polydnavirus particles (CsPDV), and ovarian proteins (OPs). Oviposited eggs are not encapsulated, while washed eggs are encapsulated rapidly by H. virescens. Early protection from encapsulation is afforded by a group of 29-36 kD OP glycoforms. These glycoforms are endocytosed by host hemocytes within 30 min post-parasitization (pp) and disrupt hemocyte spreading behavior and egg encapsulation through at least 24 h p.i. Purified CsPDV does not protect eggs from encapsulation early, but disrupts hemocyte spreading and egg encapsulation from 24 h through at least 5 days p.i. Functional activity of CsPDV appears to be correlated with time-dependent accumulation of virus-specific proteins in parasitized insects. We propose that the fast-acting 29-36 kD OP protects Campoletis eggs from encapsulation until accumulation of CsPDV proteins which sustain immunosuppression.  相似文献   
980.
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