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131.
The 2‐(hydroxymethyl)pyridine modified C60 (PY‐C60) and methoxydiglycol modified C60 (MDG‐C60) are synthesized using Bingel‐Hirsch reaction and characterized by nuclear magnetic resonance (NMR) and mass spectra. PY‐C60 and MDG‐C60 can bind to glucose oxidase (GOx) and quench the fluorescence of tryptophan (Trp) residue in GOx through static mechanism. The conformation of GOx is disturbed after formation of complex with these fullerene derivatives. Kinetic analysis indicates that PY‐C60 and MDG‐C60 may affect the catalytic activity of GOx with a partial mixed‐type inhibition mechanism. In the plasma glucose concentration range (3.6–5.2 mmol·L?1), PY‐C60 may significantly accelerate the catalytic velocity of GOx, however, MDG‐C60 exerts almost no obvious change to the initial velocity of GOx, suggesting that elaborate design of molecular structure of fullerene derivative is very important for regulating the biological activity of fullerene‐enzyme complex. 相似文献
132.
Li G Yi Z Bai Y Zhang W Zhang H 《Dalton transactions (Cambridge, England : 2003)》2012,41(34):10194-10198
NaNbO(3) single-crystal films with (100), (110) and (111) oriented crystal planes were grown on LaAlO(3) (100), (110) and (111) substrates by pulsed laser deposition. The NaNbO(3) films exhibit anisotropy in the photocatalytic oxidization activity for Rhodamine B (RhB) degradation. The increasing order of RhB degradation in Ar atmosphere under full arc irradiation of a Xe lamp is (100) < (110) < (111), which is consistent with that of ˙OH generation. The good linear relationship between the activity of RhB degradation and the coercive electric field indicates that the photocatalytic activity is closely related to the ferroelectric property. 相似文献
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135.
由于空间环境中宇宙辐射无处不在,工作在空间环境的光纤系统必须考虑辐致损伤特性。建立了10GHz的射频光纤链路传输系统,分别采用单模光纤和保偏光纤作为传输媒质。利用60 Co`γ射线源,在剂量率1rad/s总剂量50krad下,对射频光纤链路进行辐照实验,对两种系统做对比分析。实验结果表明,单模光纤链路的辐致损耗绝对值较大,保偏光纤链路的辐致损耗绝对值较小;单模光纤的幂律模型指数较保偏光纤大,即同样的辐照剂量,单模光纤受影响程度大。在辐照起主要影响因素的阶段,单模光纤延时差受辐照影响程度较保偏光纤稍小。辐致损耗和辐致延时差对光纤长度都有线性累加作用。从整体水平看,50krad的辐射总剂量对两种光纤造成的损伤并不大,传输的信号仍在可用的范围之内。 相似文献
136.
基于旋转调制的自补偿技术是进一步提高激光陀螺仪捷联惯导系统导航精度的有效方法。研究了旋转调制捷联惯导系统中的激光陀螺仪误差补偿方法。建立旋转式捷联惯导系统激光陀螺仪的误差传播方程,分析激光陀螺仪旋转误差效应及误差传播特性,在此基础上建立了调制策略编排目标函数;研究了双轴交替旋转调制模式下的调制策略编排方案,提出了一种改进的16次序双轴交替旋转调制方法,建立了基于双轴转动角速度的动态误差方程,实现了转动过程中激光陀螺仪的常值项误差、标度因数误差、安装误差的有效补偿,进一步抑制速度误差积累所引起的位置误差。仿真结果验证了该方法的有效性,提高了捷联惯导系统导航精度,可为旋转调制光学捷联惯导系统设计提供理论参考。 相似文献
137.
Guoqiang He Zaoxue Yan Dr. Mei Cai Prof. Dr. Pei Kang Shen Dr. Min‐Rui Gao Dr. Hong‐Bin Yao Prof. Dr. Shu‐Hong Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8490-8497
Carbide‐based electrocatalysts are superior to traditional carbon‐based electrocatalysts, such as the commercial Pt/C electrocatalysts, in terms of their mass activity and stability. Herein, we report a general approach for the preparation of a nanocomposite electrocatalyst of platinum and vanadium carbide nanoparticles that are loaded onto graphitized carbon. The nanocomposite, which was prepared in a localized and controlled fashion by using an ion‐exchange process, was an effective electrocatalyst for the oxygen‐reduction reaction (ORR). Both the stability and the durability of the Pt‐VC/GC nanocomposite catalyst could be enhanced compared with the state‐of‐the‐art Pt/C. This approach can be extended to the synthesis of other metal‐carbide‐based nanocatalysts. Moreover, this straightforward synthesis of high‐performance composite nanocatalysts can be scaled up to meet the requirements for mass production. 相似文献
138.
Experimental study of rotation effect on film cooling over the flat wall with a single hole 总被引:3,自引:0,他引:3
Zhi Tao Xiaojun Yang Shuiting Ding Guoqiang Xu Hongwei Wu Hongwu Deng Xiang Luo 《Experimental Thermal and Fluid Science》2008,32(5):1081-1089
A new rotating test rig was set up to investigate the rotation effect on the film cooling over the flat wall. A simple flat blade with an inclined 30° film hole, which is parallel to the hot mainstream, was installed. And different rotation orientations were selected to simulate the blade pressure or suction side of a turbine blade. A steady liquid crystal technique was applied to obtain detailed distribution of the temperature over the blade surface. And the average adiabatic film cooling effectiveness of the area adjacent to the film hole was selected to evaluate the cooling effect. Five different rotational speeds, i.e., 0, 300, 500, 800, 1000 r/min, were considered. Experimental results indicate that the film trajectory could bend under the rotating condition. With the increase of the rotational speed, on the pressure side, the film trajectory inclines centripetally firstly and then centrifugally; whereas, on the suction side the film trajectory bends centrifugally. On the other hand, as the rotational speed increases, the cooling effect is improved firstly and then worsened when Ω > 500–600 r/min on the pressure side. On the suction side, however, the cooling effect is not sensitive to the rotational speed. 相似文献
139.
基于体-面混合积分方程方法,研究了介质导体复合结构目标的电磁散射特性.对导体采用面积分方程,对介质应用体积分方程,由等效原理建立以导体面电流及任意非均匀介质体极化电流为未知量的矩阵方程,利用稳定的双共轭梯度并结合快速傅立叶变换技术(BiCGS-FFT)来加速矩阵方程求解,相对于传统的矩量法大大降低了计算时间和内存需求.数值结果验证了该方法的正确性.同时,它为复杂复合结构目标散射特性研究奠定了一定的基础. 相似文献
140.
Gefu Ji Zhenyu Ouyang Guoqiang Li Samuel Ibekwe Su-Seng Pang 《International Journal of Solids and Structures》2010,47(18-19):2445-2458
The interfacial fracture of adhesively bonded structures is a critical issue for the extensive applications to a variety of modern industries. In the recent two decades, cohesive zone models (CZMs) have been receiving intensive attentions for fracture problems of adhesively bonded joints. Numerous global tests have been conducted to measure the interfacial toughness of adhesive joints. Limited local tests have also been conducted to determine the interface traction-separation laws in adhesive joints. However, very few studies focused on the local test of effects of adhesive thickness on the interfacial traction-separation laws. Interfacial toughness and interfacial strength, as two critical parameters in an interfacial traction-separation law, have important effect on the fracture behaviors of bonded joints. In this work, the global and local tests are employed to investigate the effect of adhesive thickness on interfacial energy release rate, interfacial strength, and shapes of the interfacial traction-separation laws. Basically, the measured laws in this work reflect the equivalent and lumped interfacial fracture behaviors which include the cohesive fracture, damage and plasticity. The experimentally determined interfacial traction-separation laws may provide valuable baseline data for the parameter calibrations in numerical models. The current experimental results may also facilitate the understanding of adhesive thickness-dependent interface fracture of bonded joints. 相似文献