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分析了某公司热轧厂主设备——飞剪的构造、工作原理和机械设计的要点,并对其剪切机构进行了运动学分析和优化设计。编制Matlab程序,进行优化计算。优化后,在剪切区内剪刃剪切倾角和连杆水平速度均匀性两项指标均有所提高。通过对飞剪机构的分析及优化设计,可以更好地了解设备的特性,各种设备参数或工艺参数对工件加工质量的影响,为飞剪的设计或改进、设备工艺参数的制定,提供了可靠的参考依据。 相似文献
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Lanthanum hexaboride nanopartieles, with high emission electrons in cathode materials and peculiar blocking near infrared wavelengths, were applied for many aspects. Based on the quasi-static approximation of Mie theory, the size dependent optical prop- erties of LaB6 nanoparticles were researched, such as refractive index n(ω), extinction coefficient k(ω), reflectivity R(ω), absorption coefficient a(ω), and electron energy loss L(ω). Due to the localized surface plasmon resonance (LSPR), the extinction coefficient k(ω) and absorption coefficient a(ω) depended on the size, and the LSPR peaks red-shifted with sizes increased, which was different from that of bulk materials. In addition, electron energy-loss spectrum L(co) showed electrons oscillation reinforced, since electrons absorbed the photon energy and generated resonance. Further, reftectivity R(ω) and refractive index n(ω) indicated that the light in near infrared region could not be propagated on the surface of LaB6 materials, which exhibited metallic behaviors. So the resonance peak of LaB6 nanoparticle was located in near-infrared region, making use of this property for solar control glazing and heat-shielding application. 相似文献
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利用热注入法合成带有油酸配体的PbS量子点, 用短链乙醇胺替代长链油酸做为PbS量 子点的配体。 对比了由两种材料制得的量子点薄膜与Al形成的肖特基结的J-V特性,采用热 电子发射理论对其J-V特 性进行分析,结果发现,接有短链乙醇胺的PbS量子点薄膜具有更优的整流特 性,理想因子n为3.8,明显低 于采用油酸配体的PbS量子点(n=4.6)。 研究表明,短链配体有利于提高PbS薄膜表面的均匀性并形成较好的肖 特基接触;短链置换过程提高了量子点薄膜与Al电极的接触势垒高度,使肖特基结反向 漏电流降低。 相似文献
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ZnO nanorods prepared by a solution-phase method are annealed at different temperatures in oxygen ambient.The luminescence properties of the samples are investigated.In the same excitation condition,the photoluminescence(PL) spectra of all samples show an ultraviolet(UV) emission and a broad strong visible emission band.The asymmetric visible emis-sion band of annealed samples has a red-shift as the annealing temperature increasing from 200 ℃ to 600 ℃ and it can be deconvoluted into two subband emissions centered at 535 nm(green emission) and 611 nm(orange-red emission) by Gaussian-fitting analysis.Analyses of PL excitation(PLE) spectra and PL spectra at different excitation wavelengths reveal that the green emission and the orange-red emission have a uniform initial state,which can be attributed to the electron transition from Zn interstitial(Zni) to oxygen vacancy(Vo) and oxygen interstitial(Oi),respectively. 相似文献
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国家安全生产监督管理局局长张宝明在日前召开的全国煤矿安全生产电话会议上指出:山西省连续发生的5起特大事故,暴露出煤矿安全专项整治,特别是小煤矿关闭整顿工作中存在着突出问题:一是地方政府特别是县乡政府的负责人,对关闭整顿小煤矿的极端重要性认识不足,态度不坚决,措施不得力,工作不落实,存在着地方保护主义倾向和不负责任的官僚主义、形式主义问题,以会议落实会议,以文件落实文件,没有切合实际的关闭措施;对小煤矿存在的以停代整、停而不整,以停代关、昼停夜开、明停暗开等现象,睁只眼闭只眼;个别干部在小煤矿入股… 相似文献
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ZnS:Er量子点材料制备及其受激发光特性研究 总被引:1,自引:1,他引:0
在水性介质中,制备了ZnS:Er量子点,并对其的X射线(XRF)谱、X射线衍射(XRD)谱、透射电子显微镜(TEM)图像和光致发光(PL)谱进行了研究,确定了所制备的ZnS:Er量子点材料中Er的浓度,观测到ZnS:Er量子点呈粒径为4nm的近球型结构。利用LD激发,在LD不同电流强度下得到ZnS:Er量子点从波长1500nm到1650nm的宽谱发射,并随着电流强度的增加ZnS:Er量子点的发射强度明显增加,当电流强度达到1.5A时,1545nm波长处的发射峰更明显。 相似文献