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61.
黄土构造节理研究及其应用 总被引:3,自引:0,他引:3
作者发现大量不同力学性质的黄土构造节理后,识别了它们的区域性、系统性特征;认定其两组扭裂面代表新构造应力场最大剪切应力方向,利用黄土构造节理系及由其控制的土层沟槽网络恢复了相应地区Q3-4构造应力场;提出构造节理是黄土区地下水运移的主要通道和赋存的场所;发现构造节理是黄土区地裂缝、滑坡、崩塌和水土流失等地质灾害的构造基础之一,证实构造节理是黄土地层的软弱面,风化和继之而来的应力侵蚀就由此开始,进而逐步塑造黄土碟、穴、井、桥、柱、墙、沟等潜蚀地貌和部分侵蚀地貌。研究黄土构造节理对恢复新构造应力场、帮助预测地裂乃至地震活动、控制水土流失和滑塌灾害、进行工程乃至区域稳定性评价、重新认识黄土潜蚀地貌发育规律、指导干旱半干旱黄土区找水,既有理论意义又有实际意义。 相似文献
62.
Cigarette smoking can damage DNA and induce spontaneous mutagenesis or carcinogenesis. Here, we describe a novel strategy for in situ monitoring of cigarette smoke-induced DNA oxidation damage and offer a method for screening natural compounds that protect DNA against tobacco smoke. The present protocol takes advantage of a fast and simple magnetic separation/mixing method and a highly sensitive chemiluminescence (CL) ELISA. The DNA immobilized on the magnetic beads was oxidized by the smoke in the absence or presence of natural compounds, and then oxidative DNA was conveniently held by magnetic force, whereas the complex tobacco smoke matrix and any remaining compounds were completely eliminated by extensive washing, and possible interferences were thus removed and oxidative damage was then sensitively monitored by CL ELISA. A library of 32 natural products was then screened and three were found to protect DNA from oxidative damage and thus may be promising compounds for the development of new drugs. Moreover, the protection effect of these three natural compounds against DNA oxidation damage was successfully classified by directly spiking them in the reference cigarettes. In addition, the potential to screen a mixture in a complex sample matrix, such as crude extracts, was also demonstrated, and hence the proposed technique can screen compounds within a complex matrix and enhance the screening throughput. 相似文献
63.
Shen Jianzhong Zhang Suxia Wu Congming Jiang Haiyang Wang Zhanhui Cheng Linli 《Chromatographia》2010,71(1-2):163-165
A method was developed to simultaneously detect six resorcylic acid lactones in feed by GC–MS. Samples were extracted with methanol followed by a two step liquid–liquid extraction and an HLB SPE clean-up. The samples were derivatized with BSTFA + TMCS (99/1; v/v) and determined by GC–MS. For all analytes, the ranges of recoveries were 81.2–98.2%, with RSDs of 3.2–15.2%, and the LODs were 0.2–0.6 μg kg−1.
相似文献64.
A series of C10-BridgePHOS oxides possessing different substituted groups on the diphenyl phosphine system were synthesized and tested as organocatalysts in the allylation of aldehydes with allyltrichlorosilane, providing chiral homoallylic alcohols. These types of organocatalysts showed high catalytic activity and only 2 mol% catalyst loading was required to induce short reaction times. Under optimal reaction conditions, excellent product yields and up to 92% ee were obtained for a variety of substrates. 相似文献
65.
Xiuqiao Xiang Jianzhong Zhou Li Mo Zhimeng Luo Chaoshun Li 《Applied mathematics and computation》2009,215(3):881-888
For the purpose of further saving computing time, an improved algorithm about NSFOT is provided in this paper. That is, by introducing the simple operations such as preprocessing or after-processing, Haar and Walsh transforms are performed conveniently on the multiprocessor. As a result, one large size problem is divided into several small size sub-problems, load on every processor not only decreases greatly but also gets so uniform that much time is saved. Both the theoretical analysis and experimental results demonstrate the effectiveness of the proposed approach. 相似文献
66.
67.
The biodegradation rate and biocompatibility of poly (d, / -lactide) (PDLLA)in vivo were evaluated. The aim of this study was to establish a nerve guide constructed by the PDLLA with 3-D microenvironment and
to repair a 10 mm of sciatic nerve gap in rats. The process of the nerve regeneration was investigated by histological assessment,
electrophysiological examination, and determination of wet weight recovery rate of the gastrocnemius muscle. After 3 weeks,
the nerve guide had changed from a transparent to an opaque status. The conduit was degraded and absorbed partly and had lost
their strength with breakage at the 9th week of postoperation. At the conclusion of 12 weeks, proximal and distal end of nerves
were anastomosed by nerve regeneration and the conduit vanished completely. The results suggest that PDLLA conduits may serve
for peripheral nerve regeneration and PDLLA is a sort of hopeful candidate for tissue engineering. 相似文献
68.
In this paper, we consider the network improvement problem for multicut by upgrading nodes in a directed tree T = (V, E) with multiple sources and multiple terminals. In a node based upgrading model, a node v can be upgraded at the expense of c(v) and such an upgrade reduces weights on all edges incident to v. The objective is to upgrade a minimum cost subset S ⊆ V of nodes such that the resulting network has a multicut in which no edge has weight larger than a given value D. We first obtain a minimum cardinality node multicut Vc for tree T, then find the minimum cost upgrading set based on the upgrading sets for the subtrees rooted at the nodes in Vc. We show that our algorithm is polynomial when the number of source–terminal pairs is upper bounded by a given value. 相似文献
69.
该文介绍一类岩性反演问题.从理论上分析LMS估计的结构。在空间齐次假设下,得到不变矩阵α=(αij)的递推计算关系.同时,建立一种计算机模拟岩性的算法,该算法被实践证明是有效的. 相似文献
70.
Jianzhong Zhu I. G. Vasileva J. I. Gibner T. Y. Shilkina Z. I. Boris 《Fresenius' Journal of Analytical Chemistry》1992,342(4-5):363-366
Summary An apparatus for the selective dissolution as a chemical method of phase analysis and its operating conditions are described. Using ICP-AES as determination method an example for the YBCO system is found in the phase YBa2–0.04Cu3+0.03Ox and a BSCCO system is found in three phases of 35.6% Bi2(Sr,Ca)4–0.08Cu3–0.05Ox, 30.1% Bi2(Sr,Ca)3–0.09Cu2–0.08Ox and 34.3% Bi2(Sr,Ca)2–0.07Cu1–0.05Ox. 相似文献