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951.
通过水泥稳定碎石施工中的材料、施工中、养护事先控制,从而提高工程施工质量,进而提高工程质量. 相似文献
952.
对7例患者肾移植术后并发重症病毒性肝炎的病回进行了分析。发现所有患者均为HBSAg阳性的HBV感染者,2例重叠HCV感染,HAV和HDV重叠感染各1例。表明HBV感染及在此基础上其它肝炎病毒合并感染是发生重症肝炎的主要原因;治疗过程中环孢素A的应用和它所引起的肝肾毒性是移植后重症肝炎发生和影响患者预后的一个重要因素。提出应慎重考虑HBV感染者的肾移植适应症,有HCV、HDV重叠感染者不宜施行肾移植术。对HBsAg阳性肾移植患者应加强术后肝功能的监测,及早应用保肝药物。 相似文献
953.
本文分析了低增生性急性白血病(HAL)与胃烟性白血病(SAL)低原始细胞性白血病(OBL)及MDS的异同点,提出HAL的诊断标准:①初诊病例骨髓呈灶性增生减低或重度减低,原+早(幼)≥本系细胞30%;②骨髓活检印片有核细胞增生亦呈减低现象,病理切片示造血组织减少。应取消SAL及OBL的命名,以防止分类上的混乱。 相似文献
954.
955.
近年来随着交通量的增加和重型车辆、超吨车辆的增加 ,白灰土作为上基层已不能满足形势的需要 ,为解决上述问题 ,结合在国道、省干道工程中就利用水泥稳定类基层进行探索。 相似文献
956.
957.
To study flame propagation in a spark ignition engine, it must concentrate on the initial combustion stage, i.e., the formation and development of flame. Therefore, we must study the theoretical calculation of minimum flame kernel radius which affects the formation and development of flame kernel. To calculate the minimum flame kernel radius, we must know the thermal conductivity, flame temperature, laminar burning velocity, etc. To evaluate the accuracy of the minimum flame kernel radius based on the theory, authors compared with those from calculation and those from tests. According to the increase of number of sparks and spark intervals, the flame kernel radii become to increase and the expected lean limits are extended. It is considered that is due to the stability of combustion as increase of flame kernel size according as high ignition energy supplies in initial period and discharge energy period lengthens. 相似文献
958.
In this study, cooperative regenerative braking control of front-wheel-drive hybrid electric vehicle is proposed to recover optimal braking energy while guaranteeing the vehicle lateral stability. In front-wheel-drive hybrid electric vehicle, excessive regenerative braking for recuperation of the maximum braking energy can cause under-steer problem. This is due to the fact that the resultant lateral force on front tire saturates and starts to decrease. Therefore, cost function with constraints is newly defined to determine optimum distribution of brake torques including the regenerative brake torque for improving the braking energy recovery as well as the vehicle lateral stability. This cost function includes trade-off relation of two objectives. The physical meaning of first objective of cost function is to maximize the regenerative brake torque for improving the fuel economy and that of second objective is to increase the mechanical-friction brake torques at rear wheels rather than regenerative brake torque at front wheels for preventing front tire saturation. And weighting factor in cost function is also proposed as a function of under-steer index representing current state of the vehicle lateral motion in order to generalize the constrained optimization problem including both normal and severe cornering situation. For example, as the vehicle approaches its handling limits, adaptation of weighting factor is possible to prioritize front tire saturation over increasing the recuperation of braking energy for driver safety and vehicle lateral stability. Finally, computer simulation of closed loop driver-vehicle system based on Carsim? performed to verify the effectiveness of adaptation method in proposed controller and the vehicle performance of the proposed controller in comparison with the conventional controller for only considering the vehicle lateral stability. Simulation results indicate that the proposed controller improved the performance of braking energy recovery as well as guaranteed the vehicle lateral stability similar to the conventional controller. 相似文献
959.
Recent studies on the new congestion reduction method―tradable credit scheme rely on the full information of speed‐flow relationship, demand function, and generalized cost. As analytical travel demand, functions are difficult to establish in practice. This paper develops a trial and error method for selecting optimal credit schemes for general networks in the absence of demand functions. After each trial of tradable credit scheme, the credit charging scheme and total amount of credits to be distributed are updated by both observed link flows at traffic equilibrium and revealed credit price at market equilibrium. The updating strategy is based on the method of successive averages and its convergence is established theoretically. Our numerical experiments demonstrate that the method of successive averages based trial and error method for tradable credit schemes has a lower convergence speed in comparison with its counterpart for congestion pricing and could be enhanced by exploring more efficient methods that make full use of credit price information. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
960.