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101.
A novel optical element, axilens, proposed by Davidson et al., for achieving extended focal length is introduced. We propose a method to design the binary axilens which has high diffraction efficiency. Using computer numerical simulation, we designed 4 axilenses each has different parameters. In this paper we present our results and make comparison with that in ref. [1]. The properties of binary axilens such as the focal depth, the lateral resolution and the intensity distribution along axis is discussed. 相似文献
102.
本文用“剖面不变性”确定等效电子热导系数,研究了TCA装置上阿尔芬波加热的能量平衡,结果与实验符合很好。证明本文所用的方法对不同装置、不同加热方式都适用。 相似文献
103.
Nickel-cobalt binary oxide/reduced graphene oxide (G-NCO) composite with high capacitance is synthesized via a mild method for electrochemical capacitors. G-NCO takes advantages of reduced graphene oxide (RGO) and nickel-cobalt binary oxide. As an appropriate matrix, RGO is beneficial to form homogeneous structure and improve the electron transport ability. The binary oxide owns more active sites than those of nickel oxide and cobalt oxide to promote the redox reaction. Attributed to the well crystallinity, homogeneous structure, increased active sites, and improved charge transfer property, the G-NCO composite exhibits highly enhanced electrochemical performance compared with G-NiO and G-Co3O4 composites. The specific capacitance of the G-NCO composite is about 1750 F g?1 at 1 A g?1 together with capacitance retention of 79 % (900/1138 F g?1) over 10,000 cycles at 4 A g?1. To research its practical application, an asymmetric supercapacitor with G-NCO as positive electrode and activated carbon as negative electrode was fabricated. The asymmetric device exhibits a prominent energy density of 37.7 Wh kg?1 at a power density of 800 W kg?1. The modified G-NCO composite shows great potential for high-capacity energy storage. 相似文献
104.
105.
随着人口老龄化的不断加剧,衰老相关疾病已成为全球关注的问题.神经系统功能的退行性改变居于衰老相关疾病的首位,其机制尚不明了.该文旨在通过核磁共振磷谱(~(31)P NMR)检测不同月龄大鼠脑组织中小分子物质的改变,明确能量相关的含磷化合物随大鼠年龄增长的变化,从而揭示脑组织中年龄相关代谢物的变化规律.该研究萃取了不同年龄(幼年、中年及老年)Sprague-Dawley(SD)大鼠脑组织中的小分子物质,进行了~(31)P NMR检测分析.结果显示:老年大鼠脑组织中能量代谢相关物质——磷酸肌酸的含量显著升高,而磷脂酰胆碱及磷酸肌醇含量显著降低,并且出现了磷酸化葡萄糖.这一发现有助于理解衰老相关的脑结构和功能下调,为神经退行性疾病的发生提供依据. 相似文献
106.
Wuyou Fu Shikai Liu Wenhua Fan Haibin Yang Xiaofen Pang Jing Xu Guangtian Zou 《Journal of magnetism and magnetic materials》2007
Spinel CoFe2O4 coating on the surface of hollow glass microspheres of low density was synthesized by co-precipitation method. The phase structures, morphologies, particle size, shell thickness, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDS). The results show that CoFe2O4 coating on hollow glass microspheres can be achieved, and the coating layers are constituted by CoFe2O4 nanoparticles of mean size ca. 10 nm. The as-synthesized powder materials were uniformly dispersed into the phenolic cement, then the mixture was pasted on metal plate with the area of 200 mm×200 mm as the test plate. The test of microwave absorption was carried out by the radar-absorbing materials (RAM) reflectivity far field radar cross-section (RCS) method. The results indicate that the coated CoFe2O4/hollow glass microspheres composites can be applied in lightweight and strong absorption microwave absorbers. 相似文献
107.
108.
We investigate the linearization of systems of n-component nonlinear diffusion equations; such systems have physical applications in soil science, mathematical biology and invariant curve flows. Equivalence transformations of their auxiliary systems are used to identify the systems that can be linearized. We also provide several examples of systems with two-component equations, and show how to linearize them by nonlocal mappings. 相似文献
109.
Jing Yang Xiao-Min Zhang Dong-Xia Hu Wen-Yi Wang Jing-Qin Su Feng Jing Sheng-Zhi Zhao 《Optics & Laser Technology》2007,39(1):123-128
We have discussed the optical and laser properties of different laser glass types. According to the properties of the gain and the B integral in the high-power laser amplifier chain, an optimal configuration is pointed out to improve the output capability at short pulses based on reducing nonlinear refractive index n2. In this way, high gain glasses and low n2 glasses are used in different amplifier stages simultaneously. The simulated results show that on the condition that the maximal output energies of both the configurations are same at 3 and 5 ns, the maximal output capability growth ratio of 30.48% () and 42.24% () for the optimal configuration can be obtained at 1 ns, respectively. 相似文献
110.
甲氧氯普胺和盐酸普鲁卡因顺序注射光谱研究和测定 总被引:1,自引:0,他引:1
在酸性介质中,铈(Ⅳ)与甲氧氯普胺和盐酸普鲁卡因反应生成不稳定的红色产物,研究了不同条件下的光谱吸收曲线,初步探讨了反应机理,并据此建立了顺序注射光度法测定甲氧氯普胺和盐酸普鲁卡因的新方法。测定甲氧氯普胺方法的线性范围9.71~116.6 μg·mL-1,检出限6.5 μg·mL-1,进样频率45 h-1。测定盐酸普鲁卡因的方法的线性范围10.0~130.0 μg·mL-1,检出限7.4 μg·mL-1,进样频率45 h-1。用于针剂和胃复安药片中甲氧氯普胺的含量以及针剂中盐酸普鲁卡因含量的测定,并与标准测定方法对照,经统计学处理无显著性差异,结果满意。 相似文献