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排序方式: 共有609条查询结果,搜索用时 31 毫秒
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Ohne Zusammenfassung 相似文献
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On the suitability of agricultural by-products for the manufacture of granular activated carbon 总被引:1,自引:0,他引:1
An investigation of several agricultural by-products revealed that their suitability for activated carbon production is not determined by general material-specific features (elemental composition) but by type-specific features. A coarse-cellular structure (as in wood), which is indicated by porosities of the raw materials higher than 35% is disadvantageous. A specific change in the properties of cokes (porosity, density, hardness) is possible by varying the conditions of pyrolysis. By rapid heating in the pyrolysis step, for instance, macroporous residues are produced. Temperature and burnoff have the greatest influence on the quality of the activated carbon during the activation step. Of the investigated materials, coconut shells yield granular activated carbon of the highest quality. The following order of suitability of raw materials for activated carbon production was established: coconut shells> peach stones> plum stones> hazelnut shells> walnut shells> cherry stones. 相似文献
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A numerical model based on the finite-element method for solving the nonlinear diffusion equation of ion-exchange in glasses is presented. The model is applied to the calculation of the concentration profile for a Ag+-Na+ ion-exchanged channel waveguide. The calculated concentration profile is in good agreement with a measured refractive-index profile of a waveguide fabricated with the same parameters as used in the calculations 相似文献
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Erhard Ueckermann 《Zeitschrift für Jagdwissenschaft》1994,40(1):68
Ohne Zusammenfassung 相似文献
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Translated the MMPI into American Sign Language (ASL) via the back-translation procedure and recorded it on videotape to determine the linguistic equivalency of a sign language translation of a psychological test for use with deaf individuals. The bilingual retest technique was conducted whereby both forms of the instrument were administered to 28 ASL-English bilingual deaf Ss. Due to the advent of the MMPI-2 during the conduct of this study, a new set of T scores was calculated from the present MMPI data to compare the effect of shifting to the MMPI-2 norms. The results demonstrate adequate linguistic equivalencies of the ASL MMPI items and underscore the potential utility and practicality of future ASL translations of psychological tests for use with deaf individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
B. S. Seplyarskii S. V. Kostin G. B. Brauer 《International Journal of Self-Propagating High-Temperature Synthesis》2008,17(2):121-124
Explored is the filtration combustion in Ti-(Ti + 0.5C) layered powder systems in a coflow of nitrogen gas. The presence/absence
of nitrogen coflow through the layered system was found to drastically affect the character of wave propagation and structure/properties
of product. The obtained data can be regarded as a basis for fabrication of new layered and composite materials in the mode
of dynamic filtration combustion.
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Experiments have been performed to investigate the mechanical response of unfilled polycarbonate vis‐à‐vis the influence of prior deformation on stress relaxation and creep. Piecewise linear deformation histories, which involve strain‐controlled tensile loading of a specimen to a maximum load and partial unloading to a target strain/stress point as prologue to a relaxation test, have been shown to qualitatively influence the recorded stress‐time behavior. In particular, the stress magnitude during relaxation first increases and is then followed by a decrease. Analogously, in creep tests during unloading, the strain might decrease and then increase. Time characteristics for this U‐turn in the deformation response are influenced by the placement of the test. The influence of prior specimen conditioning on this phenomenon is investigated by comparing test data from virgin samples to that of specimens having high (~85%) inelastic strain from prior tensile elongation. Findings suggest that the observed persistence in the occurrence of this reversal effect for both types of specimens is evidence of the need to incorporate this behavior into the fold of material modeling. Additionally, this novel relaxation and creep behavior has been observed in other amorphous (poly(phenylene oxide)) and crystalline (high‐density polyethylene) polymers. Polym. Eng. Sci. 44:1783–1791, 2004. © 2004 Society of Plastics Engineers. 相似文献