倒置A2/O工艺氮平衡与脱氮效率的分析

研究了倒置A^2／O工艺中的氮平衡和脱氮效率，并对影响脱氮效率的回流比和碳氮质量比进行分析。根据广州某城市污水处理厂水质特点，设计总回流比为3．0，其中污泥回流比为1．0，混合液回流比为2．0，理论总氮去除率为78．75％，实际运行总氮去除率达64．42％。     

西藏盐井盐泉地下热卤水水化学特征分析

地下水化学成分受地质、水文地质、岩性等因素的控制，水化学特征研究对水资源的利用、管理及保护具有重要的指导作用。西藏自治区芒康县盐井乡境内，沿澜沧江近岸边长约1．5km范围内出露有50余处矿化度较高、水温为中高温、无色、味咸的天然盐泉。这种地下热卤水的分布特征、水化学特征和化学组分的形成，受地质构造、地下水径流通道、径流速度等条件的影响，因此通过对其水样水化学特征的研究，进一步阐明盐泉形成的基本规律。     

2006年就业市场环境分析

2005年就业市场的运行特点 2005年三季度完成全年就业和再就业工作目标任务的90%和78% 2005年1月至9月,全国实现新增城镇就业人员810万人,达到全年目标任务（900万）的90%,下岗失业人员再就业390万人,达到全年目标任务（500万人）的78%（数据来源于劳动保障部2005年三季度新闻发布材料）.其中,帮助“4050”人员再就业88万人,达到全年目标任务（100万人）的88%.三季度末,全国共有城镇登记失业人员835万人,城镇登记失业率4.2%,与上年底持平.     

环境模型在风险评估中的应用

环境模型方法是化学品风险评估中经常使用的方法。环境模型可提供化学品的浓度、归趋和主要迁移转化途径等信息,目前已被广泛应用于各类环境系统中。本文对该方法使用的一般步骤进行介绍,并对我国的环境模型工作提出了几点建议。     

基于故障物理和数理统计相结合的可靠性加速试验方法

目的 研究通过加速试验在较短时间内对高可靠性、小子样电子产品的可靠性进行评估的方法.方法 分析可靠性加速试验方案的特点,梳理可靠性加速试验方案制定的基本流程,通过结合数理统计和故障物理技术,研究加速应力的确定方法和加速因子的计算模型,给出加速试验条件及试验时间的确定流程以及相应的试验结果评估方法,并进行案例应用.结果 该方法克服了常规可靠性加速试验方案设计中仅依靠经验并需要大样本量的缺点,科学有效地解决了高可靠性、小样本产品的可靠性加速试验方案设计问题,形成了电子设备基于故障物理和数理统计相结合的可靠性加速试验方案设计方法,经验证合理可行.结论 该试验方法能够满足当前可靠性要求高、进度紧、受试样品有限的武器装备研制的需求.     

Online single particle measurement of fireworks pollution during Chinese New Year in Nanning

Time-resolved single-particle measurements were conducted during Chinese New Year in Nanning, China. Firework displays resulted in a burst of SO_2, coarse mode, and accumulation mode(100–500 nm) particles. Through single particle mass spectrometry analysis, five different types of particles(fireworks-metal, ash, dust, organic carbon-sulfate(OC-sulfate), biomass burning) with different size distributions were identified as primary emissions from firework displays. The fireworks-related particles accounted for more than70% of the total analyzed particles during severe firework detonations. The formation of secondary particulate sulfate and nitrate during firework events was investigated on single particle level. An increase of sulfite peak(80SO_3~-) followed by an increase of sulfate peaks(97HSO_4~-+ 96SO_4~-) in the mass spectra during firework displays indicated the aqueous uptake and oxidation of SO_2 on particles. High concentration of gaseous SO_2, high relative humidity and high particle loading likely promoted SO_2 oxidation. Secondary nitrate formed through gas-phase oxidation of NO_2 to nitric acid, followed by the condensation into particles as ammonium nitrate. This study shows that under worm, humid conditions, both primary and secondary aerosols contribute to the particulate air pollution during firework displays.     

某油田蒸汽驱油项目职业病危害风险程度的判定

通过现场调查及检测等分析方法,对某油田蒸汽驱油项目职业病危害风险程度该如何判定进行分析讨论。分析认为,蒸汽驱油项目虽为石油开采行业的一个生产环节,但生产工人不接触石油与天然气,其原料为水,产品为水蒸气,其生产性质与"热力生产与供应业"相似,因此定性为"职业病危害较重"更符合实际生产情况。     

锑矿区人发中铋的污染状况

采用氢化物发生-原子荧光光谱法（HG-AFS）,对经过硝酸-高氯酸消解后的锡矿山矿区和贵阳市人体头发样品中重金属铋（Bi）含量进行分析。结果表明,锡矿山矿区和贵阳市人体头发中Bi的检出率分别为95.5%、22.7%,矿区居民人体头发中Bi含量显著高于作为对照的贵阳市居民人体头发中的Bi含量。锡矿山矿区男性和女性居民人发中Bi质量分数范围分别为0.0079～0.1842μg？g-1、0.0080～0.1403μg？g-1,平均值（中位数）分别为0.0480（0.0280）μg？g-1、0.0482（0.0397）μg？g-1,矿区较高的人发Bi含量主要集中在30～49岁的中年人群中。通过独立样本t检验发现,锡矿山矿区男性和女性发样中Bi含量差异不显著（p〉0.05）。研究结果说明锑矿开采和冶炼区域重金属Bi对人体健康的危害明显比非矿区严重。     

Methane/coal dust/air explosions and their suppression by solid particle suppressing agents in a large-scale experimental tube

Methane/coal dust/air explosions under strong ignition conditions have been studied in a 199 mm inner diameter and 30.8 m long horizontal tube. A fuel gas/air manifold assembly was used to introduce methane and air into the experimental tube, and an array of 44 equally spaced dust dispersion units was used to disperse coal dust particles into the tube. The methane/coal dust/air mixture was ignited by a 7 m long epoxypropane mist cloud explosion. A deflagration-to-detonation transition (DDT) was observed, and a self-sustained detonation wave characterized by the existence of a transverse wave was propagated in the methane/coal dust/air mixtures.The suppressing effects on methane/coal dust/air mixture explosions of three solid particle suppressing agents have been studied. Coal dust and the suppressing agent were injected into the experimental tube by the dust dispersion units. The length of the suppression was 14 m. The suppression agents examined in this study comprised ABC powder, SiO₂ powder, and rock dust powder (CaCO₃). Methane/coal dust/air explosions can be efficiently suppressed by the suppression agents characterized by the rapid decrease in overpressure and propagating velocity of the explosion waves.     

Towards Sustainable Integrated Watershed Ecosystem Management: A Case Study in Dingxi on the Loess Plateau, China

The Chinese government initiated a massive conservation program called “Grain-for-Green” in 1999 to reduce soil erosion and improve ecosystem function. Implementing practical sustainable development in the loess plateau still remains problematic, particularly in its eco-fragile areas. Here we discussed an approach for sustainable development at the watershed scale by integrating land use suitability, ecosystem services and public participation in the loess hilly area. We linked land use scenario analysis and economic modeling to compare the outcomes of three scenarios, CLU (Current Land Use), GOLU (Grain-production Oriented Land Use) and PSLU (Potential Sustainable Land Use). The results indicated that compared to PSLU, GOLU may provide a higher economic productivity in the short-term, but not in the long-term. CLU ranked lowest in terms of economic benefits and did not meet the daily needs of the local farmers. To reconcile the land use adjustments with farmers’ basic needs, a labor-saving land use strategy is necessary. Since the PSLU scenario assumes that slope cropland should be converted to pastures or orchards, more time may be available for off-farm work and for more public participation in integrated ecosystem management. Financial support to the local farmers for environmental conservation should be modulated in function of their positive contribution to ecosystem management.