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681.
Objective To investigate the distribution of brain-derived neurotrophic factor(BDNF) protein in the rabbit retina. Methods Immune response material in the retina was observed using BDNF antibody by the method of immunohistochemistry. Results BDNF gene expression was mainly found in the RGCs, also in innernuclei cells and outernuclei cells in rabbit retina. Conclusion RGC is not only the target cell of BDNF, but also express the BDNF protein. BDNF from multi-sources participates in the regulation of RGCs.  相似文献   
682.
城市交通与信息化   总被引:1,自引:0,他引:1  
信息技术的不断发展为城市交通运行改善带来新的契机,城市交通与信息化是一个对中国未来城镇化模式影响非常深远的命题。首先从道路交通管理、公共交通服务、交通综合信息平台等六个方面阐述中国交通信息化的发展状况,总结交通信息化在信息采集、数据分析、决策支持、信息发布以及社会关注五个方面的发展趋势。指出交通信息化应更关注城市交通、都市圈交通的特点,在认识城市交通本质和服务对象的基础上进行总体设计。最后,强调智能交通信息化发展目标应与城市整体发展目标相一致,应考虑公众、企业、政府层面的不同诉求进行交通信息化的顶层设计。  相似文献   
683.
针对大跨曲线连续刚构桥弯扭耦合导致结构线形施工控制异常复杂的问题,在总结曲线刚构桥线形影响因素的基础上,提出了施工恒载零弯矩的大跨曲线连续刚构桥线形控制系统和具体实现措施。为验证所提措施的有效性,以曲率半径1 200 m、主跨80 m的江西会昌九岭高架桥为例,采用有限元法对不同曲率半径下增加预应力束或临时斜拉塔辅助合龙实现恒载零弯矩的措施与传统设计进行了分析对比。结果表明:增加预应力束,或者临时斜拉塔辅助合龙可大大减少结构的竖向位移、横向位移和扭转位移,可以简化大跨曲线连续刚构桥施工线形控制的难度。  相似文献   
684.
给定两个广义反射矩阵P,Q,通常对于矩阵方程AX=B关于P,Q的自反解和反自反解的研究大多是通过矩阵分解或广义奇异值分解来进行的。采用广义逆,建立该方程存在自反解和反自反解的充要条件以及解的一般表达式,并研究与之相关的矩阵最佳逼近问题。  相似文献   
685.
Along with higher and higher integration of intellectual properties (IPs) on a single chip, traditional bus-based system-on-chips (SoC) meets several design difficulties (such as low scalability, high power consumption, packet latency and clock tree problem). As a promising solution, network-on-chips (NoC) has been proposed and widely studied. In this work, a novel algorithm for NoC topology synthesis, which is decomposing and cluster refinement (DCR) algorithm, has been proposed to minimize the total power consumption of application-specific NoC. This algorithm is composed of two stages: decomposing with cluster generation, and cluster refinement. For partitioning and cluster generation, an initial low-power solution for NoC topology is generated. For cluster refinement, the clustering is optimized by performing floorplan to further reduce power consumption. Meanwhile, a good tradeoff between power consumption and CPU time can be achieved. Experimental results show that the proposed method outperforms the existing work.  相似文献   
686.
An improved numerical method is used to simulate the dynamic behavior of a two part towing cable systems during turnings. In U turns and full turns, periodical heave motions are found both for the towed vehicle and for the depressor. Periodic motions of the subsea units and of the cable surface tension are closely related to the turning parameters, such as turning velocity and turning radius. System parameters, such as length of the second cable and the vehicle hydrodynamics, also damp turning instability.  相似文献   
687.
To get the movement mode and driving mechanism similar to human shoulder joint, a six degrees of freedom (DOF) serial-parallel bionic shoulder joint mechanism driven by pneumatic muscle actuators (PMAs) was designed. However, the structural parameters of the shoulder joint will affect various performances of the mechanism. To obtain the optimal structure parameters, the particle swarm optimization (PSO) was used. Besides, the mathematical expressions of indexes of rotation ranges, maximum bearing torque, discrete dexterity and muscle shrinkage of the bionic shoulder joint were established respectively to represent its many-sided characteristics. And the multi-objective optimization problem was transformed into a single-objective optimization problem by using the weighted-sum method. The normalization method and adaptive-weight method were used to determine each optimization index’s weight coefficient; then the particle swarm optimization was used to optimize the integrated objective function of the bionic shoulder joint and the optimal solution was obtained. Compared with the average optimization generations and the optimal target values of many experiments, using adaptive-weight method to adjust weights of integrated objective function is better than using normalization method, which validates superiority of the adaptive-weight method.  相似文献   
688.
689.
This research presents a multi-band hybrid mobile phone antenna based on electromagnetic coupling,which can be applied to mobile handheld devices, occupying a small board space of 39.7 mm × 15.6 mm on the system circuit board. By adding resonant and coupled branch instead of multi-feed on the traditional bent antenna,this design provides four wide operating bands of 0.772—0.998 GHz, 1.540—1.600 GHz, 1.680—2.270 GHz and2.300—2.690 GHz with the hybrid feature of planar inverted-F antenna(PIFA), L-shape, U-shape and S-shape structures, which cover nine-band, i.e., GSM850, GSM900, GPS1575, DCS1800, PCS1900, IMT200, LTE2300,LTE2600 and Blue Tooth/Wi-Fi. Ansoft software HFSS is used in this research to make the antenna performance better and the operating principle of the proposed antenna is described in detail. Result of simulation reveals that the maximum gains of these four wide bands are 2.20,-0.99, 4.01 and 4.05 dBi, respectively. Moreover, this research also tests the return loss(S11) of the fabricated antenna with the vector network analyzer and the result is in accordance with the simulation result on the whole. There are four wide resonant frequencies which cover nine-band of wireless wide area network(WWAN), wireless local area network(WLAN) and long term evolution(LTE), when the available bandwidth is better than 6 d Bi return loss.  相似文献   
690.
城市交通治理是提升国家及城市治理能力的战略需求和重要抓手。研究面向交通服务多元主体新型关系的城市交通治理现代化理论,是提升交通服务共建、共享、共治水平的新要求和新趋势。通过梳理公共治理一般理论以及国家治理、社会治理、城市治理等相关领域治理研究的基础,从中国城市交通治理的现实需求出发,提出城市交通治理的基本内涵与技术支撑要求。围绕服务于人的需求,组织城市高效、安全、低耗可持续运行的城市交通总体目标,在以城市群为主体形态背景下,制定差异化、阶段性城市交通治理目标。  相似文献   
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