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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A non-destructive and in-situ technique for the measurement of tritium in materials, namely β-ray-induced X-ray spectrometry (BIXS), has been developed recently. In the present study a V-4Cr-4Ti alloy was pre-heated at 1000℃ for 2 h to form a recrystallization structure before the tritium absorption experiments were conducted. Firstly the hydrogen isotope gas was charazterized by means of a quadrupole mass spectrometer (QMS) and a small-sized ionization chamber. Then hydrogen isotope absorption tests of V-4Cr-4Ti alloy were performed at 400 ℃ and the atomic concentration of hydrogen isotope in V-4Cr-4Ti alloy was estimated as 0.17% with a tritium content of approximately 2.5 ppm. Experimental results indicate that BIXS is a quite useful tool for quantitatively measuring the tritium content and tritium distribution in the surface layers of vanadium alloys and no strong trapping effects of tritium exist in the pre-heated V-4Cr-4Ti alloy. 相似文献
992.
993.
994.
995.
电控柴油机以其节能、环保、易于控制等特点。获得了广泛的应用。为了更好地了解该项新产品,使其尽早在石油机械上推广使用。提升中国石油机械的品质,文章对电控柴油机的特点、结构及应用前景进行了讨论。 相似文献
996.
KS Choi JJ Nah CU Choi YJ Ko HJ Sohn G Libeau SY Kang YS Joo 《Canadian Metallurgical Quarterly》2003,96(1):1-16
An experimental competitive enzyme-linked immunosorbent assay (morbillivirus cELISA) using a recombinant N antigen (rRPV N) expressed in a baculovirus and a ruminant morbillivirus (RPV and PPRV)-specific monoclonal antibody (P-13A9) was developed for simultaneous detection of rinderpest virus (RPV) and peste des petits ruminants virus (PPRV) antibodies and its diagnostic performance was evaluated. A set of known reference antisera against RPV and PPRV belonging to different lineages, experimental sera from cattle vaccinated for a RPV of Asian lineage, and field sera from cattle and sheep/goat populations known to be positive (West Africa) and negative (Korea) for RPV and PPRV were used for the evaluation. Morbillivirus cELISA results on the panel of experimental RPV and PPRV antisera showed high correlation (r=0.97) between the whole virus and the rRPV N antigens, suggesting that the rRPV N contains a ruminant morbillivirus-specific antigenic determinant recognized by the P-13A9 and it may be suitable as an ELISA antigen in place of the whole virus. Morbillivirus cELISA detected anti-RPV and anti-PPRV antibodies in all reference RPV and PPRV antisera containing VN titers >/=1:8, suggesting that the assay can simultaneously detect antibodies against RPV and PPRV. Anti-RPV antibody was detected by morbillivirus cELISA in vaccinated cattle as early as the VNT and continued to be detectable by both the cELISA and the VNT until termination of the study. When applied to field samples from Africa, morbillivirus cELISA showed good agreement with a RP cELISA kit (kappa value of 0.86) in bovine sera and with a peste des petits ruminant cELISA kit (kappa value of 0.81) in caprine/ovine sera. Usefulness of morbillivirus cELISA using the rRPV N protein was discussed. 相似文献
997.
Treated was an anti-plane crack perpendicular to the interface of an exponential-type FGM strip bonded to another linear-type
FGM substrate with infinite thickness. Through Fourier integral transform, the problem was reduced as a Cauchy singular integral
equation, which was further solved numerically by the Lobatto–Chebyshev collocation method. Based on the numerical solution,
the effects of the geometrical and physical parameters on the stress intensity factor (SIF) were analyzed and the following
conclusions were obtained: (a) A notable discrepancy between the interface-perpendicular crack and the interfacial one is
that, to reduce the weak-discontinuity of interface or to make the interface micro-discontinuous will not necessarily decrease
the SIF of the former, but will surely decrease that of the latter. (b) When a crack tip is situated very near to the interface
(or free surface), its SIF will be high and totally dominated by the interface (or free surface). (c) To increase the stiffness
of the FGM on one side of the interface is beneficial to preventing the crack on the other side from growing toward the interface.
Besides, some practical suggestions were further given for material design in the field of composites. 相似文献
998.
999.
我国跳汰选煤市场简析 总被引:1,自引:0,他引:1
通过对我国跳汰选煤的用户及制造厂家情况的调研,认为跳汰选煤仍是我国主要的选煤工艺。介绍了国内外跳汰机制造厂家的产品经营现状,分析了现存的问题。 相似文献
1000.
岩性圈闭预测方法及应用 总被引:2,自引:0,他引:2
随着油田勘探技术的不断进步和勘探目标的日益深化,地质目标从寻找大构造、发展到寻找微幅度构造和非构造的隐蔽油气藏。以往的研究结果表明,岩性预测方法由于受到地震资料分辨率及技术条件等因素的限制,其研究方法及对成果的认识都有其局限性,从而使预测的合理性和精度都不高,因此,本文以高分辨率地震资料为基础,应用测井、钻井及地震等资料,从沉积微相分析入手,建立了不同砂体类型的地质及地震正演模型,并根据地震反射波组特征、地震反演的阻抗值及其它地震属性参数,综合确定出研究区域的砂体变化及其分布规律。总结出一套针对薄互层特点的岩性圈闭识别技术,并在大庆长垣以西古龙和英台—大安地区的实际应用中取得了明显的效果。 相似文献