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311.
Visible-light-driven photocatalysis as a green technology has attracted a lot of attention due to its potential applications in environmental remediation. Vesicle Cd Se nano-semiconductor photocatalyst are successfully prepared by a gas template method and characterized by a variety of methods. The vesicle Cd Se nano-semiconductors display enhanced photocatalytic performance for the degradation of tetracycline hydrochloride, the photodegradation rate of78.824% was achieved by vesicle Cd Se, which exhibited an increase of 31.779% compared to granular Cd Se. Such an exceptional photocatalytic capability can be attributed to the unique structure of the vesicle Cd Se nano-semiconductor with enhanced light absorption ability and excellent carrier transport capability. Meanwhile, the large surface area of the vesicle Cd Se nano-semiconductor can increase the contact probability between catalyst and target and provide more surface-active centers. The photocatalytic mechanisms are analyzed by active species quenching. It indicates that h+and UO_2~-are the main active species which play a major role in catalyzing environmental toxic pollutants. Simultaneously, the vesicle Cd Se nano-semiconductor had high efficiency and stability.  相似文献   
312.
The status of energy consumption and air pollution in China is serious. It is important to analyze and predict the different fuel consumption of various types of vehicles under different influence factors. In order to fully describe the relationship between fuel consumption and the impact factors, massive amounts of floating vehicle data were used. The fuel consumption pattern and congestion pattern based on large samples of historical floating vehicle data were explored, drivers'' information and vehicles'' parameters from different group classification were probed, and the average velocity and average fuel consumption in the temporal dimension and spatial dimension were analyzed respectively. The fuel consumption forecasting model was established by using a Back Propagation Neural Network. Part of the sample set was used to train the forecasting model and the remaining part of the sample set was used as input to the forecasting model.  相似文献   
313.
Environmental exposure and health risk upon engineered nanomaterials are increasingly concerned. The family of mesoporous carbon nanomaterials(MCNs) is a rising star in nanotechnology for multidisciplinary research with versatile applications in electronics,energy and gas storage, and biomedicine. Meanwhile, there is mounting concern on their environmental health risks due to the growing production and usage of MCNs. The lung is the primary site for particle invasion under environmental exposure to nanomaterials. Here, we studied the comprehensive toxicological profile of MCNs in the lung under the scenario of moderate environmental exposure. It was found that at a low concentration of 10 μg/mL MCNs induced biophysical inhibition of natural pulmonary surfactant. Moreover, MCNs at similar concentrations reduced viability of J774 A.1 macrophages and lung epithelial A549 cells.Incubating with nature pulmonary surfactant effectively reduced the cytotoxicity of MCNs.Regarding the pro-inflammatory responses, MCNs activated macrophages in vitro, and stimulated lung inflammation in mice after inhalation exposure, associated with lung fibrosis.Moreover, we found that the size of MCNs played a significant role in regulating cytotoxicity and pro-inflammatory potential of this nanomaterial. In general, larger MCNs induced more pronounced cytotoxic and pro-inflammatory effects than their smaller counterparts. Our results provided valuable information on the toxicological profile and environmental health risks of MCNs, and suggested that fine-tuning the size of MCNs could be a practical precautionary design strategy to increase safety and biocompatibility of this nanomaterial.  相似文献   
314.
为提高剩余污泥的破解效果并降低能耗,采用FS(fluid shear,流体剪切)、UC(ultrasonic cavitation,超声空化)、FS和UC联合工艺(FS-UC,UC-FS)破解剩余污泥,并应用单因素试验结合响应面法对联合工艺进行优化.结果表明:FS对剩余污泥破解效果一般,只在开始阶段具有较好效果,随作用时间延长,破解效果未有显著提高甚至下降.UC对剩余污泥破解效果明显,随作用时间延长,破解效果显著提升,但能耗也随之增大,EDR(energy disintegration ratio,效能比)明显下降.相同作用时间下,UC破解效果优于FS破解效果,UC破解剩余污泥的DDCOD(degree of disintegration,破解率)与EDR均明显高于FS方法.单因素试验得出的较优FS作用时间范围为2~8 min,较优UC作用时间范围为5~15 min.响应面法试验结果显示,联合工艺的剩余污泥破解效果和能量利用率均优于单一方法,联合工艺中FS-UC工艺的破解效果优于UC-FS工艺.FS-UC工艺的最佳参数:FS处理5.6 min再UC处理15.0 min,该条件下剩余污泥实际DDCOD为50.8%,EDR为26.8%.UC-FS工艺的最佳参数:先UC作用15.0 min再FS作用7.8 min,该条件下剩余污泥实际DDCOD为36.5%,EDR为17.1%.研究显示,以DDCOD和EDR为指标,4种工艺的高效性顺序为FS-UC > UC-FS > UC > FS,其中FS-UC工艺具有能耗低、破解效率高的特点,是4种工艺中剩余污泥破解效果最好的一种工艺.   相似文献   
315.
针对小城市污水排放量历史数据较少,城市发展变化较大的特点,以楚雄市为例,提出了基于污水排放来源以及生成机理的预测方法。根据历史人口增长趋势以及城镇化率进行城区人口综合预测,运用定额法根据不同行业用水特点预测城市用水量,结合城市污水排放特点对楚雄市近期以及远期城市污水排放量进行科学合理的预测,并对预测结果进行了分析,可为城市发展规划提供决策参考。  相似文献   
316.
Global marine capture fisheries are undergoing serious stress, with overfishing as one of the major problems. In order to mitigate the overexploitation of capture fisheries, government regulation or fisheries management is necessary. Among various management approaches, vessel quantity control is being widely employed. To achieve effective governance of fisheries, the technical efficiency (TE) issue needs to be considered in the implementation of vessel quantity control. Using the Pacific saury (Cololabis saira) stick-held dip net fishery in Japan as a case study, this paper estimated the TE of sampled fishing vessels and explored the possible factors affecting the gap in efficiency. This paper aims to provide suggestions for a better implementation of vessel quantity control in global Pacific saury fishery, and also to serve as an empirical example of integrating TE analysis into management of overexploited fisheries for achieving satisfactory effects. Results show the TE score of the sampled fishery averaged around 0.7 from 2009 to 2014, and factors concerning owners/skippers’ motivation such as vessel ownership and specialization, vessel tonnage as well as skippers’ age show positive effects on the TE. Our findings in the present work provide important strategies for mitigating overexploitation in fisheries. Conducting technical efficiency analysis of targeted fisheries is a vital issue to be considered for designing and realizing an effective implementation of fisheries management approaches. The large vessels and the enthusiasm of vessel owners/skippers need to be particularly addressed when vessel quantity limit is considered to mitigate the problem of overfishing.  相似文献   
317.
为有效提升艰险地区地质调查作业人员安全装备保障水平,结合艰险地区作业环境特点和地质调查作业人员安全装备配备现状,从气象和气候条件、地理环境、自然灾害、人文地理四个方面进行了安全风险分析,并依据事故发生的可能性和严重性将风险划分为5个等级,最终按照"立足实际、重点优先、优化配置"原则提出了由个体防护、应急自救、人员定位、野外生存4类系统组成的地质调查作业人员安全装备保障体系以及安全装备配备建议,以期能够最大限度地降低安全风险对作业人员的影响,从根本上解决艰险地区地质调查作业人员个体防护用品配备标准适用性差、安全装备系统化程度低、个体防护用品整体质量不高、安全装备更新不及时不到位等突出问题,可为今后地质调查作业人员安全装备保障体系建设以及安全装备配备提供指导和参考。  相似文献   
318.
舰面设备可靠性试验工程实践   总被引:1,自引:1,他引:0       下载免费PDF全文
目的开展舰面设备可靠性试验工程实践。方法在舰面设备研制阶段,策划提出关键单机与系统相结合的可靠性试验方案。结果快速提高舰面设备的系统可靠性。结论近几年多个型号舰面设备的可靠性试验工程实践,有效促进了海军导弹武器系统的整体可靠性水平的提高,为其他舰面设备的可靠性工程提供参考。  相似文献   
319.
依据美国环保署颁布的储罐VOCs排放量核算公式,从环境参数、原油参数和储罐结构参数3个方面对外浮顶储罐VOCs排放的影响进行了研究,其中包括了边缘密封排放挂壁排放、浮盘附件排放和浮盘着陆期间排放等几个相关排放核算数学公式。结果表明:环境风速增大,环境温度升高或太阳辐射强度提高均导致排放量增大;原油温度升高或原油周转量增加也导致排放量增加;储罐直径增加,罐漆颜色浅,或者罐壁锈蚀情况好会降低VOCs排放量。  相似文献   
320.
介绍了国内外浮顶原油储罐VOCs泄漏损耗形式。结合美国环保署(EPA)发布的AP-42中第7章储罐的VOCs相关排放公式,建立了外浮顶原油储罐VOCs排放量核算的方法,并对核算方法的应用进行了举例分析,有助于掌握现阶段原油外浮顶储罐的泄漏损耗量,为推进企业绿色低碳发展,控制原油储罐VOCs总量排放提供参考。  相似文献   
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