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991.
水热法制备BiVO_4及其光催化性能研究 总被引:1,自引:0,他引:1
采用水热反应法并改变反应条件制备不同形貌和晶体结构的BiVO4可见光催化剂,并探讨不同形貌BiVO4的形成机制及其光催化活性的影响因素。借助X-射线衍射(XRD)、扫描电子显微镜(SEM)及固体紫外-可见漫反射光谱(DRS)对产品进行表征,并在可见光(λ〉420 nm)照射下考察其降解亚甲基蓝(MB)的光催化性能。结果表明,高温更有利于单斜型钒酸铋的生成,反应初始pH值对钒酸铋的形貌影响较大。反应过程中,前驱液中的颗粒通过溶解再结晶、定向聚集自组装、熟化过程最终形成不同形貌的钒酸铋颗粒。钒酸铋的光催化降解速率主要受其晶粒粒径和晶体微观应变的影响,晶粒粒径越大,微观应变越小,结晶度越好,降解速率越高。 相似文献
992.
(1 − x)Bi0.5Na0.5TiO3-xBi0.5K0.5TiO3 [BNT-BKT-100x] thin films have been successfully deposited on Pt/Ti/SiO2/Si substrates by a sol-gel process together with rapid thermal annealing. A morphotropic phase boundary (MPB) between Bi0.5Na0.5TiO3 and Bi0.5K0.5TiO3 was determined around x ∼ 0.15. Near the MPB, the film exhibits the largest grain size, the highest ε value (360) and the largest Pr value (13.8 μC/cm2). The BNT-BKT thin film system is expected to be a new and promising candidate for lead-free piezoelectric applications. 相似文献
993.
集群并行显示系统在超高分辨、大数据信息高速显示等方面优势明显,但是集群节点机接收用户指令和信息显示输出存在不同步的问题。为了解决这一问题,文中研究了集群并行显示技术,分析了信息显示处理不同步的原因,提出了用户指令同步、渲染显示同步等同步机制,解决了用户交互处理同步和显示渲染输出同步等问题。实验结果证明,文中的集群并行显示同步技术是有效的,可以有效地实现用户指令和集群显示输出的同步。 相似文献
994.
Beta分子筛作为一种重要的催化材料,被广泛应用于石油化工、煤化工及环境保护等领域,但其常规的水热合成过程存在成本高、单釜产率低和废水排放量大等问题。本研究提出了一条基于天然矿物介尺度结构解聚-重组装的无溶剂绿色合成Beta分子筛的新路线,采用该路线所合成的Beta分子筛(Beta-Anhyd)含有丰富的介孔和大孔结构,且具有较商业Beta分子筛(Beta-Ref)更高的比表面积和更低的酸量,以其为载体,通过脱Al补Sn制备的Sn-Beta催化剂(Beta-Anhyd-Deal)在丙烷脱氢反应中表现出较参比催化剂(Beta-Ref-Deal)更加优异的催化性能。 相似文献
995.
Jan‐Chan Huang 《应用聚合物科学杂志》2004,94(4):1547-1555
Experimental values of Flory–Huggins parameters, χ, between polymers and probes, are frequently used to determine the solubility parameters of the polymers by the method of DiPaola–Baranyi and Guillet. The solubility parameters of probes were usually estimated by using heat of vaporization. When χ is measured at a temperature near the critical temperature of the probes and used to determine the solubility parameter of polymers, the departure of enthalpy of the probe vapor from the ideal gas state should be considered. This study discussed the method to make the correction and its effect on the determination solubility parameter of polymers. Without correction in the vapor phase enthalpy, the solubility parameters of the probes and polymer tend to be underestimated and the error increases when the critical temperature is approaching. Analytical expressions for the effect of correction on the solubility parameter of probes and parameters of polymers were derived. By use of probes with a range of solubility parameters on both sides of the solubility parameter of polymers, the correlation between parameters of polymers was shown to be reduced. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1547–1555, 2004 相似文献
996.
997.
We consider the setting of a multiprocessor where the speeds of the m processors can be individually scaled. Jobs arrive over time and have varying degrees of parallelizability. A nonclairvoyant
scheduler must assign the processes to processors, and scale the speeds of the processors. We consider the objective of energy
plus flow time. We assume that a processor running at speed s uses power s
α
for some constant α>1. For processes that may have side effects or that are not checkpointable, we show an W(m(a-1)/a2)\Omega(m^{(\alpha -1)/\alpha^{2}}) bound on the competitive ratio of any randomized algorithm. For checkpointable processes without side effects, we give an
O(log m)-competitive algorithm. Thus for processes that may have side effects or that are not checkpointable, the achievable competitive
ratio grows quickly with the number of processors, but for checkpointable processes without side effects, the achievable competitive
ratio grows slowly with the number of processors. We then show a lower bound of Ω(log 1/α
m) on the competitive ratio of any randomized algorithm for checkpointable processes without side effects. 相似文献
998.
999.
Structural and magnetic properties of Zn1-xcoxO nanorods prepared by microwave irradiation technique
Ahmed F Kumar S Arshi N Anwar MS Koo BH Lee CG 《Journal of nanoscience and nanotechnology》2012,12(2):1386-1389
We have successfully synthesized large-scale aggregative flowerlike Zn1-xCo(x)O (0.0 < or = x < or = 0.07) nanostructures, consisting of many branches of nanorods at different orientations with diameter within 100-150 nm (tip diameter approximately 50 nm) and length of approximately 1 microm. The rods were prepared using Zinc nitrate, cobalt nitrate and KOH in 180 Watt microwave radiation for short time interval. The synthesized nanorods were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM) and DC magnetization measurements. XRD and TEM results indicate that the novel flowerlike nanostructures are hexagonal with wurtzite structure and Co ions were successfully incorporated into the lattice position of Zn ions in ZnO matrix. The selected area electron diffraction (SAED) pattern reveals that the nanorods are single crystal in nature and preferentially grow along [0 0 1] direction. Magnetic studies show that Zn1-xCo(x)O nanorods exhibit room temperature ferromagnetism. This novel nanostructure could be a promising candidate for a variety of future spintronic applications. 相似文献
1000.
Spatially Probed Plasmonic Photothermic Nanoheater Enhanced Hybrid Polymeric–Metallic PVDF‐Ag Nanogenerator 下载免费PDF全文
Chi Hao Liow Xin Lu Chuan Fu Tan Kwok Hoe Chan Kaiyang Zeng Shuzhou Li Ghim Wei Ho 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(7)
Surface plasmon‐based photonics offers exciting opportunities to enable fine control of the site, span, and extent of mechanical harvesting. However, the interaction between plasmonic photothermic and piezoresponse still remains underexplored. Here, spatially localized and controllable piezoresponse of a hybrid self‐polarized polymeric‐metallic system that correlates to plasmonic light‐to‐heat modulation of the local strain is demonstrated. The piezoresponse is associated to the localized plasmons that serve as efficient nanoheaters leading to self‐regulated strain via thermal expansion of the electroactive polymer. Moreover, the finite‐difference time‐domain simulation and linear thermal model also deduce the local strain to the surface plasmon heat absorption. The distinct plasmonic photothermic–piezoelectric phenomenon mediates not only localized external stimulus light response but also enhances dynamic piezoelectric energy harvesting. The present work highlights a promising surface plasmon coordinated piezoelectric response which underpins energy localization and transfer for diversified design of unique photothermic–piezotronic technology. 相似文献