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排序方式: 共有1016条查询结果,搜索用时 15 毫秒
91.
92.
M. Grujicic G. Arakere A. Hariharan B. Pandurangan 《Journal of Materials Engineering and Performance》2012,21(4):437-449
High-strength aluminum and titanium alloys with superior blast/ballistic resistance against armor piercing (AP) threats and
with high vehicle light-weighing potential are being increasingly used as military-vehicle armor. Due to the complex structure
of these vehicles, they are commonly constructed through joining (mainly welding) of the individual components. Unfortunately,
these alloys are not very amenable to conventional fusion-based welding technologies [e.g., gas metal arc welding (GMAW)]
and to obtain high-quality welds, solid-state joining technologies such as friction-stir welding (FSW) have to be employed.
However, since FSW is a relatively new and fairly complex joining technology, its introduction into advanced military-vehicle-underbody
structures is not straight forward and entails a comprehensive multi-prong approach which addresses concurrently and interactively
all the aspects associated with the components/vehicle-underbody design, fabrication, and testing. One such approach is developed
and applied in this study. The approach consists of a number of well-defined steps taking place concurrently and relies on
two-way interactions between various steps. The approach is critically assessed using a strengths, weaknesses, opportunities,
and threats (SWOT) analysis. 相似文献
93.
Bhari Mallanna Nagaraja Aytam Hari PadmasriBurri David Raju Kamaraju Seetha Rama Rao 《International Journal of Hydrogen Energy》2011,36(5):3417-3425
Cu-MgO is found to be an efficient catalyst for the coupling reaction of furfural (FAL) hydrogenation and cyclohexanol (CyOH) dehydrogenation. This process is not only efficient in compensating the thermodynamic equilibrium constraints in the cyclohexanol dehydrogenation and improving the yields towards cyclohexanone but also is a economical route for the synthesis of furfuryl alcohol (FFA) and cyclohexanone (Cyone) as the process do not need any external pumping of hydrogen. The effect of incorporation of various promoters viz., Co, Zn, Fe, Cr, Pd and Ni in Cu-MgO over its activity towards this coupling reaction has been studied. Incorporation of Cr in Cu-MgO catalyst is found be an advantageous in enhancing the yields of both FFA and Cyone. All other promoters though found to show higher activity for the individual reactions of FAL hydrogenation and CyOH dehydrogenation, failed to do the same in their coupling reaction. The stabilization of active species (Cu+/Cu0) by Cr which also seem to increase the synergetic interaction between Cu and MgO as observed from higher dispersion of copper (from XRD results) and easier reducibility of copper oxide (from TPR results) seem to be the factors behind its higher activity over other promoted catalysts. 相似文献
94.
PY Henry S Hariharan S Prathap TR Jeevaraj J Joseph 《Canadian Metallurgical Quarterly》1998,14(1-2):127-128
A unique case of benign sacrococcygeal teratoma associated with an N-type rectobulbar fistula is reported. 相似文献
95.
Kaupo Kukli Mikko Ritala Markku Leskelä Timo Sajavaara Juhani Keinonen David C. Gilmer Rama Hegde Raghaw Rai Lata Prabhu 《Journal of Materials Science: Materials in Electronics》2003,14(5-7):361-367
Smooth, 4–6-nm thick hafnium oxide films were grown by atomic layer deposition from HfI4 or HfCl4 and H2O on SiO2/Si(1 0 0) substrates at 300 °C. Non-uniform films were obtained on hydrogen-terminated Si(1 0 0). The stoichiometry of the films corresponded to that of HfO2. The films contained small amounts of residual chlorine and iodine. The films deposited on SiO2/Si(1 0 0) were amorphous, but crystallized upon annealing at 1000 °C. In order to decrease the conductivity, the HfO2 films were mixed with Al2O3, and to increase the capacitance, the films were mixed with Nb2O5. The capacitance–voltage curves of the Hf–Al–O mixture films showed hysteresis. The capacitance–voltage curves of HfO2 films and mixtures of Hf–Al–Nb–O were hysteresis free. 相似文献
96.
Bhagwant Persaud Ezra Hauer Richard Retting Rama Vallurupalli Kornel Mucsi 《Accident; analysis and prevention》1997,29(6):803-810
The effect on intersection crashes of converting one-way street intersections in Philadelphia from signal to multiway stop sign control was estimated. Using crash and traffic volume data for a comparison group, regression models were computed to represent the normal crash experience of signal controlled intersections of one-way streets, by impact type, as a function of traffic volume. An empirical Bayesian procedure was used to estimate what would have been the expected number of crashes at the converted intersections had they not been converted. The empirical Bayesian estimates were compared with actual counts of crashes after conversion. Estimates were obtained for different classes of crashes categorized by impact type, day/night condition, and impact severity. Aggregate results indicate that replacing signals by multiway stop signs on one-way streets is associated with a reduction in crashes of approximately 24%, combining all severities, light conditions, and impact types. 相似文献
97.
98.
K Hariharan G Braslawsky A Black S Raychaudhuri N Hanna 《Canadian Metallurgical Quarterly》1995,55(16):3486-3489
CTLs specific for tumor antigens play a major role in the immunity against cancer. We have shown that class I-restricted CTLs can be induced by injecting soluble antigens mixed in an antigen formulation (AF) that consists of squalane, Tween 80, and Pluronic L121 (S. Raychaudhuri et al., Proc. Natl. Acad. Sci. USA, 89: 8308-8312, 1992). In this study, using ovalbumin and the ovalbumin-expressing transfectoma (EG7) as a tumor model system, we examined the in vivo antitumor effect of antigen-AF mixture. Vaccination of mice with ovalbumin in AF 2 or 3 days after EG7 tumor challenge showed significant inhibition of tumor growth compared to mice vaccinated with ovalbumin in alum or in saline. Depletion of CD8+ cells at the time of immunization completely abrogated the AF-induced tumor protection, indicating that CD8+ T cells are the major effectors in tumor protection in vivo. Depletion of CD4+ cells led to a marginal loss of tumor protection, which may be the result of inhibition of ovalbumin-specific CTL response due to the lack of T-helper activity. Our results demonstrate that AF can be used in subunit vaccines to stimulate CTLs and tumor regression in vivo. 相似文献
99.
100.
Structure–Activity Relationship Study of Spider Polyamine Toxins as Inhibitors of Ionotropic Glutamate Receptors
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Dr. Xiao‐Feng Xiong Dr. Mette H. Poulsen Rama A. Hussein Dr. Niels G. Nørager Prof. Kristian Strømgaard 《ChemMedChem》2014,9(12):2661-2670
The spider polyamine toxins Joro spider toxin‐3 (JSTX‐3) and Nephila polyamine toxins‐1 and ‐8 (NPTX‐1 and NPTX‐8) are isolated from the venom of the orb‐weaver spider Nephila clavata (Joro spider). They share a high degree of structural resemblance, their aromatic head groups being the only difference, and were recently found to be very potent open‐channel blockers of ionotropic glutamate (iGlu) receptors. In this study we designed and synthesized a collection of 24 analogues of these toxins using a recently developed solid‐phase synthetic methodology. Systematic variation in two regions of the toxins and subsequent evaluation of biological activity at AMPA and NMDA subtypes of iGlu receptors provided succinct information on structure–activity relationships. In particular, one set of analogues were found to display exquisite selectivity and potency for AMPA receptors relative to the natural products. Thus, this systematic SAR study has provided new pharmacological tools for studies of iGlu receptors. 相似文献