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31.
This paper introduced systematically the present situation of the research on theory andtechnology for hard roof control of coal face in Chinese collieries.  相似文献   
32.
液压凿岩设备在我国地下矿山的应用   总被引:1,自引:0,他引:1  
十多年来,我国液压凿岩设备的研制和使用进展很大。地下矿山除了使用我国自行设计、研制的产品外,还使用根据技术引进合同生产的产品,也有一些矿山直接从国外购买,本文着重介绍这些液压凿岩设备在金属矿山、黄金和化工等矿山的应用情况。  相似文献   
33.
This study mainly focuses on the formation of isotactic polypropylene (iPP) blend morphologies with microspheres and distinct bead–string spherulites. iPP microspheres have been prepared by a simple and convenient strategy through either an isothermal or a nonisothermal crystallization process based on the macrophase‐separated structure in molten state of iPP/olefin block copolymer (OBC) blend. The dimension of the iPP spheres can be adjusted easily from about 1 µm to >10 µm by controlling the compatibility and annealing conditions. It was found that any of the following three parameters, the molecular structure of OBC (particularly the octene content), molecular weight of iPP, and annealing condition can be rescaled with others in controlling the dimension of the iPP microspheres. The mechanism of the formation of iPP microspheres was studied in detail. Surprisingly, the typical spinodal decomposition morphology with interconnected or thin sheet structure is the precursor of these microspheres. During the subsequent annealing process, it breaks up and further coarsens into spherical structure. In addition, distinct spherulites with a bead–string substructure have been obtained during the isothermal crystallization. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40863.  相似文献   
34.
大漆艺术在中国有着悠久的历史以及辉煌的成就,本文从漆艺的历史切入,阐述了大漆良好的性能对古代漆器的保护作用;重点对漆器工艺的木胎、竹胎、陶胎、金属胎、夹纻、脱胎等胎骨的器型、工艺、优缺点等进行分析;另外也对漆画、漆塑的胎骨进行了探索与革新。将整个漆工艺制胎技术进行梳理与对比。  相似文献   
35.
The first catalytic asymmetric construction of the cyclic enaminone‐based 3‐substituted 3‐amino‐2‐oxindole scaffold with potential bioactivity has been developed via chiral phosphoric acid‐catalyzed enantioselective addition reactions of cyclic enaminones to isatin‐derived imines, which afforded a series of cyclic enaminone‐based 3‐substituted 3‐amino‐2‐oxindoles in high yields and excellent enantioselectivities (up to 99% yield, 97% ee). The investigation of the reaction mechanism suggested that it was facilitated by a dual hydrogen‐bonding activation mode between the two substrates and the chiral phosphoric acid. Besides, this method could be utilized for a large‐scale synthesis with maintained enantioselectivity. This approach will not only offer a useful method for enantioselective construction of the cyclic enaminone‐based 3‐substituted 3‐amino‐2‐oxindole scaffold, but also enrich the research on catalytic asymmetric addition reactions of isatin‐derived imines by using electron‐rich olefins as nucleophiles. More importantly, a preliminary evaluation on the cytotoxicity of some selected products revealed that two of the enantio‐pure compounds exhibited moderate to strong cytotoxicity to A549, 786‐0, ECA109 and BT474 cancer cell lines.

  相似文献   

36.
Yu  Pei  Jiang  Junxiang  Chen  Can  Wang  Zhong  Wang  Da  Li  Guangci  Li  Xuebing 《Catalysis Letters》2022,152(10):3046-3057
Catalysis Letters - Catalytic selective hydrogenation of esterified malic acid to produce 1,2,4-butanetriol (1,2,4-BT) using H2 as the reducing reagent suffers from the low 1,2,4-BT selectivity....  相似文献   
37.
Jiang  Lu  Jia  Zhiqian  Xu  Xin  Chen  Yili  Peng  Wenjuan  Zhang  Jiamin  Wang  Huimin  Li  Suoding  Wen  Jianping 《Journal of Porous Materials》2022,29(4):1071-1081
Journal of Porous Materials - Activated carbon fiber (ACF) is often used as efficient adsorption material for removal of contaminants from water. However, the propagation of microorganism on ACF...  相似文献   
38.
Bulletin of Engineering Geology and the Environment - Full-face tunnel boring machines (TBMs) are widely used in tunnel engineering projects as an efficient, safe and economical tunneling method....  相似文献   
39.
A three-step chemical synthesis of SmCo_5/Co nanocomposites was developed. Firstly, the Co-Sm(OH)_3-Ca(OH)_2 precursors were prepared by co-precipitation.Secondly, SmCo_5 particles were obtained by reductive annealing of the precursors. At last, the SmCo_5/Co nanocomposites were achieved by chemical deposition based on SmCo_5 particles. The SmCo_5/Co nanocomposites contain hard magnetic phase of SmCo_5 with about 100 nm in size and soft magnetic phase of Co with about 8 nm in size,exhibiting independent two-phase structure without alloying. Compared to that of single-phase SmCo_5 particles, the saturation magnetization of SmCo_5/Co nanocomposites is increased by 27.5%. The synthesis provides a new route to fabricate SmCo-based nanocomposites.  相似文献   
40.
In this report, fluorescence detection coupled capillary electrophoresis (CE-FL) was used to detect Protein A. Antibody was first labeled with Cy5 and then mixed with quantum dots (QDs) to form QDs-antibody bioprobe. Further, we observed fluorescence resonance energy transfer (FRET) from QDs donor to Cy5 acceptor. The bioprobe was formed and brought QDs and Cy5 close enough to allow FRET to occur. After adding protein A, the FRET system was broken and caused the FRET signal to decrease. Thus, a new method for the determination of protein A was proposed based on the FRET signal changes. This study provides a new trail of thought for the detection of protein.  相似文献   
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