不同粒径零价铁活化过硫酸钠氧化降解酸性橙7的影响及动力学研究

以偶氮染料酸性橙7(AO7)为目标污染物,研究了不同粒径零价铁(包括1 mm-ZVI、150μm-ZVI、50 nm-ZVI)对活化过硫酸钠(PS)氧化降解AO7的影响,并探讨了这3种不同粒径的零价铁活化体系中AO7的降解动力学及中间产物.结果表明,3种粒径零价铁均可以高效活化PS氧化降解AO7,反应90 min后,1 mm-ZVI、150μm-ZVI和50 nm-ZVI活化体系对AO7的去除率分别为43%、97%和100%.AO7动力学方程拟合结果表明,1 mm-ZVI和150μm-ZVI活化PS降解AO7是一级反应,50 nm-ZVI活化体系中AO7的降解是二级反应,这3种粒径零价铁活化PS降解AO7的速率常数大小顺序为50 nm-ZVI>150μm-ZVI>1 mm-ZVI.反应过程中1 mm-ZVI反应后主要生成α-Fe2O3和少量Fe3O4,150μm-ZVI表面的腐蚀产物主要是Fe3O4,而50 nm-ZVI的主要氧化物为α-Fe2O3和α-FeOOH.GC/MS检测出AO7降解中间产物有2-萘酚、邻甲酚、3-甲基-4-乙基苯酚、邻苯二甲酰亚胺、邻苯二甲酸等,AO7溶液吸收光谱的变化特征及GC/MS检测结果表明3种粒径零价铁活化PS氧化降解AO7的途径可能存在差异.     

透水混凝土抗压强度尺寸效应细观数值模拟研究

针对透水混凝土抗压强度尺寸效应问题,开展透水混凝土抗压强度尺寸效应的细观数值模拟研究.假定混凝土是由骨料、砂浆及孔隙组成,采用Monte Carlo法将孔隙与骨料颗粒随机投放在砂浆基质中,建立透水混凝土试件的细观非均质力学模型,开展透水混凝土试件压缩数值实验.研究结果表明：随着混凝土试件尺寸的增加,透水混凝土的抗压强度降低,存在尺寸效应现象;由于透水混凝土材料高度的非均匀性,其尺寸效应现象比普通混凝土明显.     

准噶尔盆地南缘黄土磁化率变化规律及影响因素

准噶尔盆地南缘柏杨河典型风成黄土剖面的岩石磁学与粒度研究结果指示该地区黄土磁 性矿物以亚铁磁性矿物为主,主要载磁矿物为粗粒原生强磁性矿物,同时含有少量细粒磁性矿物, 磁性矿物含量远低于黄土高原黄土。磁性矿物磁晶粒度以假单畴和多畴（PSD/MD）为主,后期 成壤过程对磁性矿物颗粒的改造作用很小。柏杨河黄土磁化率增强机制较为复杂,磁学与粒度 的曲线对比表明风动力强度对含磁性矿物较粗颗粒具有分选作用,是导致磁化率变化的重要因 素,但二者的低相关性又暗示了风动力强度在解释磁化率增强机制中的局限性。古尔班通古特 沙漠在末次间冰期以来的收缩与扩张导致的物源变化可能是影响磁化率变化的又一重要因素。     

新疆塔城黄土的形成

中亚黄土是研究区域古气候和古环境变化的重要载体。但是对于受到广泛研究的黄土 高原黄土来说,对中亚东部塔城黄土的报道较少。基于对塔城黄土粒度的系统分析,与伊犁盆 地黄土、典型黄土高原的黄土对比,我们发现无论是粒度频率曲线、粒度结构散点图、还是三 角图,塔城黄土与伊犁盆地清水河黄土较相似,而与黄土高原黄土不同,塔城黄土粒度频率分 布曲线为三峰分布,粒度组成比较分散,分选较差,细、中颗粒含量较少,主要以粗颗粒物质 为主,属近源风成黄土。结合当地地形和现代环流分析,我们认为中亚萨雷耶西克阿特劳沙漠 为塔城黄土提供主要的物源,盛行西风为粉尘的搬运提供足够的动力,向西开口的山间盆地地 形为粉尘的沉积提供有利的沉积中心,这三个条件的共同作用导致了塔城盆地厚层黄土的沉积。     

Unraveling the size distributions of surface properties for purple soil and yellow soil

Soils contain diverse colloidal particles whose properties are pertinent to ecological and human health, whereas few investigations systematically analyze the surface properties of these particles. The objective of this study was to elucidate the surface properties of particles within targeted size ranges (i.e. > 10, 1–10, 0.5–1, 0.2–0.5 and < 0.2 μm) for a purple soil (Entisol) and a yellow soil (Ultisol) using the combined determination method. The mineralogy of corresponding particle-size fractions was determined by X-ray diffraction. We found that up to 80% of the specific surface area and 85% of the surface charge of the entire soil came from colloidal-sized particles (< 1 μm), and almost half of the specific surface area and surface charge came from the smallest particles (< 0.2 μm). Vermiculite, illite, montmorillonite and mica dominated in the colloidal-sized particles, of which the smallest particles had the highest proportion of vermiculite and montmorillonite. For a given size fraction, the purple soil had a larger specific surface area, stronger electrostatic field, and higher surface charge than the yellow soil due to differences in mineralogy. Likewise, the differences in surface properties among the various particle-size fractions can also be ascribed to mineralogy. Our results indicated that soil surface properties were essentially determined by the colloidal-sized particles, and the < 0.2 μm nanoparticles made the largest contribution to soil properties. The composition of clay minerals within the diverse particle-size fractions could fully explain the size distributions of surface properties.     

Pollution levels and characteristics of phthalate esters in indoor air of offices

The pollution status and characteristics of PAEs (phthalate esters) were investigated in indoor air of offices, and PAEs of both gas-phase and particulate-phase were detected in all the samples. The concentration (sum of the gas phase and the particulate phase) was 4748.24 ng/m³, ranging between 3070.09 and 6700.14 ng/m³. Diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate were the most abundant compounds, together accounting for 70% of the ∑ 6PAEs. Dividing the particulate-phase PAEs into four size ranges (< 2.5, 2.5–5, 5–10, > 10 μm), the result indicated that PAEs in PM_2.5 were the most abundant, with the proportion of 72.64%. In addition, the PAE concentration in PM_2.5 correlated significantly with the total particulate-phase PAEs (R² = 0.85). Thus, the amount of PAEs in PM_2.5 can be estimated from the total amount of particulate-phase PAEs using this proportion. In a comparison between the offices and a newly decorated study room, it was found that pollution characteristics were similar between these two places. Thus, it is implied that the PAE concentration decreased by 50% 2 yr after decorating.     

生产工艺条件对菌粉爆炸特征参数的影响

利用扫描电镜及激光粒度分析仪,探究了不同生产工艺条件下医药中间体菌粉A和菌粉B的表面形状及粒径分布,并进行了热解分析,证实上述特征参数存在一定差别。在此基础上进行了爆炸特性参数研究。研究结果表明,上述两种菌粉爆炸下限处于70~90 g/m3,最大爆炸压力峰值0.4~0.5 MPa之间,爆炸性相对较弱,但也必须引起足够的重视。与菌粉B相比,菌粉A相对安全,因此条件许可时优先采用菌粉A生产工艺流程。     

Study of the explosion parameters of vapor–liquid diethyl ether/air mixtures

The knowledge of the vapor–liquid two-phase diethyl ether (DEE)/air mixtures (mist) on the explosion parameters was an important basis of accident prevention. Two sets of vapor–liquid two-phase DEE/air mixtures of various concentrations were obtained with Sauter mean diameters of 12.89 and 22.90 μm. Experiments were conducted on vapor–liquid two-phase DEE/air mixtures of various concentrations at an ignition energy of 40.32 J and at an initial room temperature and pressure of 21 °C and 0.10 MPa, respectively. The effects of the concentration and particle size of DEE on the explosion pressure, the explosion temperature, and the lower and upper flammability limits were analyzed. Finally, a series of experiments was conducted on vapor–liquid two-phase DEE/air mixtures of various concentrations at various ignition energies. The minimum ignition energies were determined, and the results were discussed. The results were also compared against our previous work on the explosion characteristics of vapor–liquid two-phase n-hexane/air mixtures.     

When is female leadership an advantage? Coordination requirements,team cohesion,and team interaction norms

This study seeks to understand to what extent and in what contexts women leaders may be advantageous for teams. More specifically, this study examines how team leader gender relates to team cohesion, cooperative learning, and participative communication. Furthermore, the study argues that advantages derived from female leadership may be contingent on teams' coordination requirements. I propose that as teams' coordination requirements increase (i.e., with functional diversity, size, and geographic dispersion), teams with women leaders report more cohesion and more cooperative and participative interaction norms than those with men leaders. I aggregated survey responses from the members of 82 teams in 29 organizations at the team level. Findings from hierarchical linear modeling analyses suggest that female leadership is more positively associated with cohesion on larger and more functionally diverse teams and more positively associated with cooperative learning and participative communication on larger and geographically dispersed teams. These results call for more research on boundary conditions on the relationship between leader gender and team outcomes, on the role of relational leadership on complex and diverse teams and, ultimately, on the potential mediating role of cohesion and team interaction norms on the relationship between leader gender and team performance. Copyright © 2015 John Wiley & Sons, Ltd.     

东海内陆架沉积物中黑碳分布及其与持久性有机污染物的相关性研究

本文采用化学热氧化法测定了25个东海内陆架表层沉积物中黑碳的含量,探讨了沉积物中黑碳与总有机碳、粒度以及持久性有机污染物之间的关系.结果表明,东海内陆架表层沉积物中黑碳的含量范围为0.21～0.88 mg.g-1.沉积物中黑碳和总有机碳之间没有显著的相关性,表明两者具有不同的来源.区域内沉积物在粒度上有明显的空间分异,黑碳的空间差异则较小,表明黑碳的沉积过程受颗粒物分选过程的影响较小.沉积物中多环芳烃和滴滴涕的含量与黑碳无显著的相关性,可能与东海内陆架环境中强烈的水动力过程和持久性有机污染物来源的复杂性有关.