排序方式: 共有24条查询结果,搜索用时 15 毫秒
1.
A two-dimensional steady-sate analysis of semi-infinite brittlecrack growth at a constant subcritical rate in an unboundedfully-coupled thermoelastic solid under mixed-mode thermomechanicalloading is made. The loading consists of normal and shear tractionsand heat fluxes applied as point sources (line loads in theout-of-plane direction). A related problem is solved exactly in an integral transformspace, and robust asymptotic forms used to reduce the originalproblem to a set of integral equations. The equations are partiallycoupled and exhibit operators of both Cauchy and Abel types,yet can be solved analytically. The temperature change field at a distance from the moving crackedge is then constructed, and its dominant term is found tobe controlled by the imposed heat fluxes. The role of this termis, indeed, enhanced if the heat fluxes serve to render thecrack as a net heat source/sink for the solid, as opposed tobeing a transmitter of heat across its plane. More generally,the influence of the thermoelastic coupling on this field, aswell as other functions, is found to increase with crack speed. 相似文献
2.
3.
Rogers CJ Eubanks LM Dickerson TJ Janda KD 《Journal of the American Chemical Society》2006,128(48):15364-15365
A series of proteins with cocaine esterase ability have been shown to hydrolyze acetylcholine with similar rate enhancements. Docking studies revealed that acetylcholine binds in a similar orientation as cocaine. These results suggest that acetylcholinesterase activity may be inherent to cocaine esterases. 相似文献
4.
5.
Amita Gupta Alexei Yu Ganin Parmanand Sharma Vikrant Agnihotri LM Belova KV Rao Mikhail E Kozlov AA Zakhidov RH Baughman 《Pramana》2002,58(5-6):1051-1059
We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show
a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are
found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there
exists no report in literature on any BiNi compound which is magnetic. 相似文献
6.
There is a growing need for technological advancements to combat agents of chemical and biological warfare, particularly in the context of the deliberate use of a chemical and/or biological warfare agent by a terrorist organization. In this tutorial review, we describe methods that have been developed both for the specific detection of biological and chemical warfare agents in a field setting, as well as potential therapeutic approaches for treating exposure to these toxic species. In particular, nerve agents are described as a typical chemical warfare agent, and the two potent biothreat agents, anthrax and botulinum neurotoxin, are used as illustrative examples of potent weapons for which countermeasures are urgently needed. 相似文献
7.
A cross-over inhibitor of the botulinum neurotoxin light chain B: a natural product implicating an exosite mechanism of action 总被引:1,自引:0,他引:1
Salzameda NT Eubanks LM Zakhari JS Tsuchikama K DeNunzio NJ Allen KN Hixon MS Janda KD 《Chemical communications (Cambridge, England)》2011,47(6):1713-1715
Clostridium botulinum produces the most lethal toxins known to man, as such they are high risk terrorist threats, and alarmingly there is no approved therapeutic. We report the first cross-over small molecule inhibitor of these neurotoxins and propose a mechanism by which it may impart its inhibitory activity. 相似文献
8.
We introduce and discuss the well-posedness of a schematic simplified mathematical model of an abstract object ‘swimming’ in the 2D nonstationary Stokes fluid. The object consists of finitely many subsequently connected small sets, each of which can act upon a pair of the adjacent sets in a rotation fashion with the purpose to generate its fish-like or rowing motion. The structural integrity of the object is maintained by respective elastic Hooke's forces. Such models are of interest in biological and engineering applications dealing with propulsion systems in fluids. Mathematics-wise, the model equations are described by a complex highly nonlinear hybrid system of partial differential equations and ordinary differential equations, which include a fluid equation and an equation describing the motion of the object in it. Our study is linked to viewing the swimming process as the one governed by multiplicative (bilinear) controls. 相似文献
9.
Spectrophotometric determination of bromide 总被引:1,自引:0,他引:1
A Spectrophotometric method for bromide determination has been developed. Bromide is converted to tribromide which absorbs at 267 nm. The detection limit is 0.01 g/ml bromide. As little as 0.4 g of bromide can be determined in an excess of chloride and sulfate with a coefficient of variation of 4%. 相似文献
10.