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911.
912.
地质灾害专题地图编制研究 总被引:1,自引:0,他引:1
地质灾害专题制图是地质灾害系统研究成果的高层次综合。本文论述了地质灾害制图的目的、原则、特点、表示内容与方法,为规划决策提供地质灾害背景图件。 相似文献
913.
本文采用11项指标并确定相应的评分标准和权重分配,对关中地区进行防旱抗旱能力的综合评价,得出关中地区属中等抗旱能力区。由于经济发展需水超过供水能力,现状及本世纪末缺水率将超过20%。因而跨流域引水是今后长期供水的途径。 相似文献
914.
对旋风除尘器在静态载荷下的强度进行了分析,发现头部顶板是较薄弱部件。通过动态载荷系数(DLF)方法,研究了旋风除尘器承受动态粉尘爆炸压力载荷时提高使用强度的可能性,结果表明,一般情况下,由于载荷的动态特性导致设备强度的变化可以忽略。 相似文献
915.
王兴昌 《长江流域资源与环境》1999,8(4):360-364
1997年11月18日,三峡工程大江截流成功,标志着第一期工程结束、进入第二期工程实施阶段。长江三峡水利枢纽具有防洪、发电、航运和供水等巨大综合效益,是跨世纪特大型水利工程。它的建设,不仅对我国能源秘至整个经济布局产生极大的影响,而且对湖北长江经济带的形成与发展具有决定性的意义。 相似文献
916.
Xing Xu Tao Zhang Shaohua Wang Zhiguang Zhou 《International Journal of Green Energy》2020,17(5):319-331
ABSTRACTEnergy management strategy (EMS) is crucial in improving the fuel economy of plug-in hybrid electric vehicle (PHEV). Existing studies on EMS mostly manage powertrain and cooling system separately which cannot get the minimum total energy consumption. This paper aims to propose a novel EMS for a new type of dual-motor planetary-coupled PHEV, which considers cooling power demand and effect of temperature on fuel economy. Temperature-modified engine model, lithium-ion battery model, two motors, and cooling system models are established. Firstly, the separated EMS (S-EMS) is designed which manages powertrain and cooling system separately. Sequentially, after the analysis of thermal characteristics of the powertrain and cooling system, the thermal-based EMS (T-EMS) is then proposed to manage two systems coordinately. In T-EMS, cooling power demand and the charging/discharging energy of motors are calculated as equivalent fuel consumption and integrated into the object function. Besides, a fuzzy controller is also established to deicide the fuel-electricity equivalent factor with consideration of the effect of temperature and state of charge on powertrain efficiency. Finally, the hardware-in-loop experiment is carried out to validate the real-time effect of EMS under the New European Driving Cycle. The result shows that cooling power demand and temperature can significantly affect the fuel economy of the vehicle. T-EMS shows better performance in fuel economy than S-EMS. The equivalent fuel consumption of the cooling system of T-EMS decreases by 27% compared with that of S-EMS. The total equivalent fuel consumption over the entire trip of PHEV using T-EMS is reduced by 9.7%. 相似文献
917.
Xinyou Lin Guangji Zhang Shenshen Wei Yanli Yin 《International Journal of Green Energy》2020,17(8):488-500
ABSTRACT The drive range of electric vehicle (EV) is one of the major limitations that impedes its universalism. A great deal of research has been devoted to drive range improvement of EV, an accurate and efficiency energy consumption estimation plays a crucial role in these researches. However, the majority of EV’s energy consumption estimation models are based on single motor EV, these models are not suitable for dual-motor EVs, which are composed of more complex transmission mechanisms and multiple operating modes. Thus, an energy consumption estimation model for dual-motor EV is proposed to estimate battery power. This article focuses on studying the operating modes and system efficiency in each operating mode. The limitation of working area of each mode ensures the vehicle dynamic performance, then PSO algorithm is adopted to optimize the torque (speed) distribution between two motors to improve the system efficiency in the coupled driving mode. Finally, the energy consumption estimation model is established by multiple linear regression (MLR). The result shows that the proposed model has a high precision in energy consumption estimation of dual-motor EV. 相似文献
918.
小城镇灾害易损性分析与评估 总被引:7,自引:0,他引:7
随着我国城镇化进程的加快 ,小城镇的防灾减灾问题逐步引起社会的关注 ,而小城镇易损度分析和评价是灾害危险性评价的重要组成部分 ,也是小城镇决策部门制定防灾减灾规划的重要依据 ;笔者在综合分析了小城镇的自然易损性、经济易损性及社会易损性的基础上 ,选取相应的灾害指标和社会经济指标 ,应用多级模糊综合评判方法 ,对小城镇的易损程度作出了评估 ,从而为小城镇制定相应防灾、减灾对策提供科学依据。 相似文献
919.
WEP的安全技术分析及对策 总被引:6,自引:2,他引:4
在对无线局域网WLAN标准IEEE80 2 .11的WEP描述的基础上 ,笔者深入研究了WEP协议的设计上和实际应用中存在的密钥序列重复使用、消息认证和完整性等严重安全漏洞 ;详细分析了标准无线局域网中WEP协议解决方案 ;提出了WEP的改进算法WEP2 ,WEP2将IV大小增加到 12 8bit,以增强抗攻击能力 ;分析了AES解决方案的可行性 ;在密钥再生与分配方面 ,提出在MAC层实现经认证的密钥交换 ,用来改善WEP的安全脆弱性等解决措施。最后 ,还对今后的研究方向作出进一步的展望 相似文献
920.
Effect of surfactants on solubilization and degradation of phenanthrene under thermophilic conditions 总被引:1,自引:0,他引:1
The bioavailability and biodegradation of polycyclic aromatic hydrocarbons (PAHs) can be increased through the addition of surfactants. Previous studies of this nature have been conducted under mesophilic conditions. Hence, the aim of the present study was to investigate the effects of synthetic surfactants and biosurfactants on solubilization and degradation of phenanthrene (PHE) in a series of batch solution experiments under thermophilic conditions. Tween 80, Triton X-100, and biosurfactants produced from Pseudomonas aeruginosa strain P-CG3 (P-CG3) and Pseudomonas aeruginosa ATCC 9027 (P. 9027) were used in this study. Surfactants effectively enhanced the solubility of PHE at 50 degrees C and the biosurfactant from P-CG3 was most effective with a 28-fold increase in apparent solubility of PHE at a concentration of 10 x critical micelle concentration (CMC) compared with the controls. However, addition of synthetic surfactants or biosurfactants inhibited the biodegradation of PHE in mineral salts medium by an isolate Bacillus sp. B-UM. Degradation of PHE diminished with increasing surfactant concentrations, and PHE degradation was completely inhibited for all the surfactants tested when the concentrations were greater than their respective CMC. The growth test suggested that Tween 80 and biosurfactants were degradable, but preferential utilization of these surfactants as substrates was not the mechanism for explaining the inhibition of PHE biodegradation. Because of the hydrophobic property of B-UM, degradation inhibition of PHE by surfactants was probably due to the reduction of direct contact between bacterial cells and PHE. 相似文献