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41.
在港口低压配电设计实例中,经常会出现一些不可忽视的常见问题,譬如变压器进线断路器的瞬时保护不满足选择性要求、开关柜出线电缆截面偏小、消防泵配电回路违反规范的强制性条文、剩余电流保护装置选型不当等。通过工程案例,分析造成设计差错的原因,并提出解决问题的思路与方法,供港口电气设计人员参考。 相似文献
42.
Angie Fredrickson 《Coastal management》2013,41(3):258-271
Consistent with the policies set forth in the Coastal Zone Management Act, the California Coastal Act seeks to balance the utilization and conservation of coastal resources, taking into account the social and economic needs of the citizens of California. One way the statute pursues this balance is through its provisions for ports. These provisions have functioned as a type of smart growth planning for ports, encouraging densification of existing port districts and possibly averting maritime commercial and industrial sprawl along the California coast. One unintended consequence of the encouraged consolidation of port activities, when combined with the rapid growth in international trade over the last four decades, has been disproportionally large environmental and health impacts on low-income and minority communities surrounding ports. This article examines how the Port of Long Beach's conformance with the California Coastal Act has resulted in ongoing environmental justice concerns. It discusses approaches employed by the Port of Long Beach to reduce environmental justice concerns resulting from significant and unavoidable environmental impacts and offers suggestions for how to address this issue. 相似文献
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张雷 《铁路通信信号工程技术》2013,10(2):22-25
随着客运专线铁路及电子商务的兴起,延伸铁路客运服务信息系统将为旅客提供更加便捷高效的服务,介绍了延伸旅客服务信息系统的总体方案及设计。 相似文献
45.
安慧 《减速顶与调速技术》2013,(3):15-17,28
介绍电磁阀故障切断报警系统的原理和结构,重点描述了电磁阀短路保护装置、CAN通讯管理机构和上位监测机,同时介绍了该系统在本森维尔车站的使用原理和效果. 相似文献
46.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(1):109-131
It is well known that track defects cause profound effects to the dynamics of railway wagons; normally such problems are examined for cases of wagons running at a constant speed. Brake/traction torques affect the speed profile due to the wheel–rail contact characteristics but most of the wagon–track interaction models do not explicitly consider them in simulation. The authors have recently published a model for the dynamics of wagons subject to braking/traction torques on a perfect track by explicitly considering the pitch degree of freedom for wheelsets. The model is extended for cases of lateral and vertical track geometry defects and worn railhead and wheel profiles. This paper presents the results of the analyses carried out using the model extended to the dynamics of wagons containing less ideal wheel profiles running on tracks with geometry defects and worn rails. 相似文献
47.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1563-1584
A virtual test rig is presented using a three-dimensional model of the elasto-kinematic behaviour of a vehicle. A general approach is put forward to determine the three-dimensional position of the body and the main parameters which influence the handling of the vehicle. For the design process, the variable input data are the longitudinal and lateral acceleration and the curve radius, which are defined by the user as a design goal. For the optimisation process, once the vehicle has been built, the variable input data are the travel of the four struts and the steering wheel angle, which is obtained through monitoring the vehicle. The virtual test rig has been applied to a standard vehicle and the validity of the results has been proven. 相似文献
48.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1518-1532
In this paper, a hybrid hydraulic passenger car (HHPC) coupled with a power split continuously variable transmission (P-CVT) is proposed. This P-CVT is capable of splitting the power from the internal combustion engine into mechanical and hydraulic power flows. By adjusting the ratio of the mechanical power to hydraulic power, the P-CVT enables the transmission ratio to be changed continuously. Meanwhile, the P-CVT system can capture the braking energy and store it in the hydraulic accumulator for the next assistant driving. In order to quantitatively investigate the effect of applying P-CVT on improving the fuel economy and operating performance for the HHPC, a numerical simulation is conducted under typical city driving conditions. The simulation results demonstrate that, the P-CVT permits the engine to be run under a more efficient operating range. The total fuel consumption of the HHPC is reduced by 16.4% under the test conditions, compared with that of the original car. 相似文献
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50.
This paper describes two identity-based broadcast encryption(IBBE) schemes for mobile ad hoc networks.The first scheme proposed achieves sub-linear size cipertexts and the second scheme achieves O(1)-size ciphertexts.Furthermore, when the public keys are transmitted, the two schemes have short transmissions and achieve O(1) user storage cost, which are important for a mobile ad hoc network.Finally, the proposed schemes are provable security under the decision generalized bilinear Di?-Hellman(GBDH) assumption in the random oracles model. 相似文献