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961.
本文系统地研究了GCr15钢球-CVDCr_7C_3镀层钢盘摩擦副滑动干摩擦引起的摩擦力(切向力)振动特性及其对材料摩擦磨损性能的影响。试件系统在垂直和水平方向上均处于低刚度、小阻尼状态。试验信号由微机采集、处理并进行频谱分析。结果表明,摩擦力振动的类型与正压力有关,而与拖动速度无关;摩擦力呈周期性自持振动时具有与相对滑动速度典型的非线性关系,振动频率接近(略低)于系统在切向的固有频率,而与拖动速度无关;摩擦力呈非平稳随机振动时,振动频率与系统在法向的振动频率有关,而与系统在切向的固有频率及拖动速度都无关;摩擦偶件运动的平稳性与摩擦力振动的类型有关,而与平均摩擦系数无关;摩擦力所耗费的能量与正压力呈比例关系。 相似文献
962.
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964.
Song Hua Yang Gang Song Hua-Lin Wang Deng Wang Xue-Qin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(2):390-397
Russian Journal of Physical Chemistry A - A series of Ag/TiO2-NaY (TY) composite adsorbents were successfully prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared... 相似文献
965.
Song Y. Z. Zhu L. C. Zhang Z. Z. Ding J. J. 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(10):1987-1993
Russian Journal of Physical Chemistry A - The azoviolet@Mn3O4 nanoparticles have been successfully synthesized using the azoviolet as a stable absorbed reagent for the supercapacitor. The prepared... 相似文献
966.
Ning Gu Miaochang Liu Hepan Wang Song Sun Zhen Zhou Weiming Hu Jin-Tao Yu Jiang Cheng 《Tetrahedron letters》2017,58(34):3398-3400
An iridium-catalyzed annulation between 1,2-diarylethanone and 3-aminopropanol was developed, leading to site specific 2,3-diarylpyridines in moderate yields. 3-Aminopropanol served as both a four-atom component and solvent during this procedure, releasing water as a clean by-product. The reaction may proceed with sequential imine formation, alcohol oxidation and intramolecular cyclization by Knoevenagel reaction. 相似文献
967.
Dr. Hong Wang Jia Jia Prof. Pengfei Song Dr. Qiang Wang Dr. Debao Li Prof. Shixiong Min Dr. Chenxi Qian Dr. Lu Wang Young Feng Li Chun Ma Prof. Tom Wu Prof. Jiayin Yuan Prof. Markus Antonietti Prof. Geoffrey A. Ozin 《Angewandte Chemie (International ed. in English)》2017,56(27):7847-7852
Herein we introduce a straightforward, low cost, scalable, and technologically relevant method to manufacture an all-carbon, electroactive, nitrogen-doped nanoporous-carbon/carbon-nanotube composite membrane, dubbed “HNCM/CNT”. The membrane is demonstrated to function as a binder-free, high-performance gas diffusion electrode for the electrocatalytic reduction of CO2 to formate. The Faradaic efficiency (FE) for the production of formate is 81 %. Furthermore, the robust structural and electrochemical properties of the membrane endow it with excellent long-term stability. 相似文献
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969.
Deña M. Agra-Kooijman Gautam Singh Michael R. Fisch M. R. Vengatesan Jang-Kun Song 《Liquid crystals》2017,44(1):191-203
ABSTRACTThe discovery of the oblique chiral (or, the twist-bend, NTB) nematic phase predicted for bent-core mesogens has engendered much interest due to its unique structure and physical properties, and the possibility of use in the next generation of fast electro-optic technology. Bimesogenic calamitic as well as bent-core mesogens are found to form the NTB phase. Here, we report direct measurements of the temperature dependence of the conical tilt and the evidence of volcano-like orientational distribution of molecules in the NTB phase. Optical and x-ray scattering investigations of two single-component calamitic bimesogens and their mixtures show that, while the Maier–Saupe orientational distribution function (ODF) is valid for the higher temperature nematic phase, a generalised expansion in terms of even Legendre functions is needed for the NTB phase. Temperature dependence of the ODFs and the order parameters 〈P2(cosβ)〉, 〈P4(cosβ)〉, and 〈P6(cosβ)〉 has been measured in both phases. The parameters 〈P2(cosβ)〉 and 〈P4(cosβ)〉 increase/decrease in the N/NTB phase with decreasing temperature, while 〈P6(cosβ)〉 remains vanishingly small for all samples. The value of 〈P4(cosβ)〉 becomes negative in the NTB phase confirming a conical distribution of molecules as they follow a helical trajectory keeping the local director tilted at an angle α wrt the macroscopic director. The heliconical tilt calculated from ODFs, exhibits a power law behaviour with temperature, vanishing at the transition to the N phase. 相似文献
970.
Shuai Huang Huanxi Zheng Jiyu Liu Jinlong Song Faze Chen Xiaolong Yang 《Journal of Dispersion Science and Technology》2017,38(4):566-569
Selective fabrication of superhydrophilic (S-philic) region on a superhydrophobic (S-phobic) surface requires complex technology and high cost, which has limited applications of extreme wettability patterns. In this paper, a twice-chemical-etching approach without special modification is used to prepare the extreme wettability patterns. Superhydrophobicity and superhydrophilicity can be successfully achieved after twice chemical etching for 20 seconds. The obtained patterns can maintain their extreme wettability for at least 30 days. Functional platforms with single-S-philic and multi-S-philic regions are fabricated to manipulate water and various organic liquids with water-film protection in an air environment. 相似文献