纳米铁酸镍的制备及可见光催化性能研究

利用水热法制备了纳米铁酸镍,表征了其微观结构和光谱性能,并以罗丹明B溶液作为目标污染物,研究了铁酸镍催化剂的可见光催化性能。结果表明:所制备铁酸镍的微观形貌为由直径200-300 nm左右的类似球形小颗粒组成的大颗粒,平均粒径为95.60 nm,在紫外-可见光谱区均有较强的光吸收。光催化过程中催化剂的适宜用量为0.05 g,少量H2O2的加入有助于提高罗丹明B溶液的降解率。催化剂用量为0.05 g,加入0.4 mL 30%的H2O2,降解50 mL 20 mg/L罗丹明B溶液,模拟太阳光照射240 min后降解率能够达到99.2%。在实际太阳光照射下,240 min后罗丹明B溶液的降解率可以达到85.2%。     

金属材料腐蚀疲劳研究进展

首先归纳了金属材料的腐蚀疲劳裂纹萌生机理和扩展机制,从材料自身因素、外界力学因素和环境因素三方面分析了腐蚀疲劳影响因素,简要介绍了环境腐蚀-疲劳载荷交互试验和环境腐蚀-疲劳载荷协同试验研究现状及重要性,并展望了金属材料腐蚀疲劳今后研究的重要方向,为金属材料腐蚀疲劳的试验开展、机理探索和工程应用奠定基础。     

Dissolved Ions of Trace and Major Elements and in Suspended Sediments in the Nile, Egypt

Dissolved ions and suspended participates from twelve water samples from Sohag (different localities) and Aswan (behind and below the High Dam) areas were collected along the River Nile, upper Egypt, which is at present affected seriously by pressure of population, intense industrial and agricultural activities, and atmospheric fallout. Eighteen trace and nine major ions in solution and fourteen metals in suspension were analyzed to establish whether elements are of anthropogenic or natural origin. Results of this study show that the Nile water was contaminated with high concentrations of dissolved lead, and with copper, nickel and mercury to a lesser extent, suggesting that these contaminants are generated from anthropogenic activities. the other dissolved ions in the Nile are of natural origin because their metal concentrations fall within the range of the normal background and average world dissolved values for inland waters. Results show that the usual constituents of suspended particulates in the Nile seem to be some metals (Cu and Zn) adsorbed on iron and manganese oxide/hydroxide. the results also reveal that most trace and major metal particulates increase from south to north due to activities associated with the dense population living along the Nile banks. No significant differences were observed between the chemical composition of trace and major elements taken on the east and west river Nile banks.     

HMX与低熔点含能材料混合物的热安定性研究

目的 研究环四亚甲基四硝胺(HMX)与2,4,6-三硝基甲苯(TNT)、2,4-二硝基苯甲醚(DNAN)、3,4-二硝基呋咱基氧化呋咱(DNTF)3种低熔点、高挥发性含能材料混合后的热安定性及相关性质.方法 将HMX与3种低熔点含能材料按照质量比1:1进行混合,采用动态测压热分析法(DPTA)、差示扫描量热法(DSC)...     

Investigation of various physicochemical and environmental parameter influence on pesticide sorption to ditch bed substratum by means of experimental design

Diffuse pollution by pesticide applied in rural catchments may contribute to alter water quality. Besides actions relative to the way the substances are introduced into the environment, it is also possible to limit the contamination by interfering on their transfer pathways from fields to the main river network. Especially, interface areas such as buffer strips or small ditches may play a major part in pesticide diffuse pollution decrease. In ditches a great variety of materials may act as sorbents for organic contaminants: grass, leaves, wood debris or sediments. In this study, laboratory experiments were designed to determine sorption characteristics for three herbicides with different physicochemical properties on sediment and leaves in decay commonly found in agricultural ditches. Sorption capacities were assessed for the herbicides isoproturon, diuron and diflufenican.

Experimental design was carried out to investigate the effects of five parameters on herbicide sorption on sediment and dead leaves. These parameters have been chosen according to parallel field experiment needs. Thus, the influence of initial sorbent moisture, herbicide form, i.e. active substance or commercial formulation, water quality (tap or natural ditch water), bromide ions (used as conservative tracers) and solid/liquid ratio have been tested. Within the parameters investigated, pesticide formulation and solid/liquid ratio were the most important parameters affecting pesticide sorption on both ditch materials.     

危险品道路运输风险分级指数法研究

危险品道路运输过程风险影响因素多,随机性和不确定性大,定量风险评价比较复杂,至今没有统一的风险评估模型.为了有效预防危险品运输事故和进行快速风险评估,基于运输危险品本身特性和相关的风险影响因素探讨了运输危险品现实风险分级指数法.该方法由危险品风险分级指数、路线影响因素和安全措施补偿因子3部分构成.危险品风险分级指数由危险品加权平均风险等级和运输危险品量、泄漏点与居民区距离以及危险品扩散因子等级确定.危险品加权平均风险等级涉及其健康危害性、可燃性、化学反应活性以及特殊危险性(氧化性和与水反应性)等级的确定.路线影响因素包含运输道路特征、气象条件、交通状况和影响人员分布4类.安全措施补偿因子为车辆、设备、容器、包装因子,人员素质因子和安全管理因子3类.该方法可对运输危险品的潜在风险进行快速分级,有利于采取有效的安全预防和控制措施,降低运输事故概率和沿线影响人员风险.     

固体废弃物在新型墙体材料中的资源化利用

探讨了工业废弃物、农业废弃物和建筑废弃物在新型墙体材料中的各种资源化利用。将各种固体废弃物变废为宝,综合利用,能够减少对环境的污染,缓解资源紧张现象,是利国利民的好途径。     

基于主成分分析法的危险货物运输企业安全评价

为更准确地评估危险货物运输企业安全等级以降低其运输风险,提出基于主成分分析法(PCA)的危险货物运输企业BP神经网络安全评价模型;在从人-机-物-环境-管理角度构建危险货物运输企业安全评价指标的基础上,分别利用该模型和其他3种模型对3家实例企业进行仿真评价和对比分析。结果表明,该模型的评价结果与期望值间的相对误差约为0.5%～1.2%,计算精度优于其他模型,且具有计算量小等特点。     

Lower back pain and its association with whole-body vibration and manual materials handling among commercial drivers in Sabah

A cross-sectional study was undertaken to determine the prevalence of lower back pain (LBP) and its association with whole-body vibration (WBV) and manual materials handling (MMH). We studied 110 commercial vehicle drivers using a self-administered questionnaire and the VI-400Pro human vibration monitor. Prevalence of LBP was 66.4%. The percentage of drivers who had frequent manual handling of heavy loads was 45.5% and those who handled heavy loads in awkward postures accounted for 86.4%. Daily vibration A(8) averaged on the z axis was 0.25 (0.06) m·s^?2 and at vector sum was 0.29 (0.07) m·s^?2. Daily vibration exposures on the z axis, frequent manual handling of heavy loads and awkward posture during MMH were significantly associated with LBP. Drivers who are exposed to WBV and frequently handle heavy loads manually and with awkward postures probably have more LBP than drivers who are exposed to only one of these risk factors.     

塑料给水管材的选用分析

给水工程中如何根据不同的场合选用合适的塑料给水管材,本文从可靠性、使用寿命和工程造价等方面进行了阐述.