东海大气气溶胶中二元羧酸的分布特征及来源

大气气溶胶中的二元羧酸因其在全球气候变化中的潜在作用而受到广泛关注.利用2011年5月12日-6月6日在东海采集的气溶胶样品,分析其中水溶性二元羧酸及常量离子浓度,探讨东海气溶胶中二元羧酸的时空分布特征及来源.结果显示东海大气气溶胶中乙二酸、丙二酸和丁二酸的浓度分别为26.0～1475.5 ng·m-3、0.1 ～61.4 ng·m-3和0.1～132.4 ng·m-3,乙二酸在这3种二元羧酸中的贡献最大,为88.3％.东海气溶胶中二元羧酸浓度的昼夜变化不显著.空间分布整体呈现近海高、远海低的趋势.气团的来源和迁移路径以及气象因素影响气溶胶中二元羧酸的分布,气团来自污染较重的陆源时气溶胶中二元羧酸的浓度较高,气团来自清洁的海洋源时,二元羧酸的浓度则较低;阴雾天气时气溶胶中二元羧酸浓度相对较高,降雨发生时二元羧酸的浓度较低.二元羧酸与常量离子的相关性分析表明,自然源和人为源释放的挥发性有机物质在液相中氧化生成二元羧酸是东海大气气溶胶中二元羧酸的主要源,而汽车尾气和生物质燃烧的一次排放、海洋源以及碱性粗颗粒吸收气体二元羧酸不是主要源.液相中乙醛酸氧化形成的乙二酸和长链二元羧酸氧化形成的乙二酸对东海气溶胶中乙二酸的贡献分别为41％和59％.     

基于地基遥感数据的太湖地区气溶胶光学厚度和粒子谱变化规律研究

利用多光谱旋转遮蔽影带辐射计(Multi-Filter Rotating Shadowband Radiometer,MFRSR)测定了我国长江三角洲中部的太湖地区2008年5月至2009年4月期间415 nm、500 nm、615 nm、673 nm、870 nm波段的全天空总辐射、散射辐射和直接辐射通量密度,结合球形粒子的Mie散射理论反演了该地区大气气溶胶粒子谱,并对结果进行了分析.结果表明:受人为活动的影响,该地区工作日和非工作日气溶胶光学厚度和粒子谱的日变化存在明显的差异,工作日上午6:00-9:00时间内,细粒子的生成远大于非工作日这一期间细粒子的生成.太湖地区气溶胶光学厚度常年较高,500 nm波段的年平均值为0.8038±0.7924,夏季最大(0.9359±0.7389),冬季最小(0.6209±0.5500);气溶胶粒子谱表现出双峰分布,一种是位于半径0.15 μm附近的细模态,另一种是半径3μm左右的粗模态,且夏季和秋季细粒子较多,而其他季节粗粒子较多.气溶胶光学厚度以及气溶胶粒子谱分布的季节变化受到气象条件的显著影响.降水过程对大气气溶胶具有明显的冲刷作用,并且降水后大气气溶胶的增加与气溶胶粒子大小有关,积聚态粒子浓度的增加比粗模态粒子的增加更快.     

磺胺甲噁唑对猪粪堆肥过程中堆料性质与酶活性的影响

以猪粪、小麦秸秆为材料,研究了磺胺甲噁唑（SMZ）对高温堆肥过程中理化性质（温度、pH值、E₄/E₆）和酶活性（纤维素酶、磷酸酶、脲酶、多酚氧化酶）的影响.结果表明：SMZ对堆肥理化性质的影响与其浓度有关.高浓度（95 mg·kg^-1）SMZ会对微生物活性产生显著抑制作用,表现出堆肥温度难以达到无害化标准,堆料pH值较低（<9.0）.但高浓度（95 mg·kg^-1）SMZ能激活多酚氧化酶活性,且水提浸液E₄/E₆值较低.在堆肥过程中,SMZ对纤维素酶和脲酶活性呈现出“抑制-激活-抑制”的作用,50 mg·kg^-1的SMZ对纤维素酶产生不同程度的激活作用.相比之下,脲酶活性对SMZ的敏感性比纤维素酶更敏感,5 mg·kg^-1的SMZ即能显著抑制脲酶活性,中浓度（50 mg·kg^-1）的SMZ对碱性磷酸酶活性产生了显著的抑制作用.综上,SMZ通过影响酶活性而影响堆肥过程的物质转化.此外,SMZ浓度越大,种子发芽指数越低.当SMZ≥50 mg·kg^-1时,堆肥难以腐熟而对植物毒性较大.     

改性壳聚糖CAD与微生物絮凝剂MBF8复配絮凝研究

采用水溶液自由基聚合反应,将丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)接枝到壳聚糖分子上制成了阳离子改性壳聚糖(CAD).经FT-IR、XRD、zeta(ξ)电位、凝胶色谱等分析确定,CAD为淡黄色透明液体,pH值为3.7,相对分子质量为2.88×10⁶,阳离子度为16.7,等电点(0.1%溶液)约为pH值10.5,有效成分2.6%,主要特征官能团有羟基、氨基、季铵基和酰胺基, 呈不规则晶体结构.将CAD与相对分子质量3.67×10⁵的多糖类电负性微生物絮凝剂MBF8复配,对浊度12~460 NTU、离子强度3.0 mmol·L^-1的高岭土悬浊液进行烧杯实验.结果表明,MBF8与CAD的最佳使用方式为先投加MBF8后投加CAD,复配比5:3时效果最好,适用的pH范围为6.0~10.0.采用PAC(3.0 mg·L^-1)+MBF8+CAD(1.0 mg·L^-1)复配絮凝,pH=8.0下,对浊度为110 NTU的高岭土悬浊液,浊度去除率>97%,残余铝<0.08 mg·L^-1,絮体大、沉降快,絮凝效果优于PAC+分子量800万、1200万的阴离子PAM及分子量1500万的阳离子PAM.     

Effect of acid solutions on plants studied by the optical beam deflection method

The optical beam deflection method was applied to study the effects of acid solution on both a terrestial and aquatic plants Egeria and Cerastium, which are common aquatic plant and terrestial weed respectively. A probe beam from a He-Ne laser was passed through a vicinity of a leaf of the plants, which were put in culture dishes filled with acid solutions. Deflection signals of the probe beam were monitored and compared for acid solutions with different pH values. The results of Egria showed that the deflection signals changed dramatically when pH values of acid solutions were 2.0 and 3.0, while little at pH of 4.0 and 5.0. For Cerastium when pH were below 3.0, deflection signals changed greatly with time at the begining. After a certain period of time, deflection signals changed little with time. When pH value was above 4.0, deflection signals of Cerastium were still changing with time even after 20 hours. The results suggested that the damage threshold of pH was between 3.0 and 4.0 for both the land and aquatic plants.     

Homogeneous and heterogeneous reactions of anthracene with selected atmospheric oxidants

The reactions of gas-phase anthracene and suspended anthracene particles with O3 and O3-NO were conducted in a 200-L reaction chamber, respectively. The secondary organic aerosol (SOA) formations from gas-phase reactions of anthracene with O3 and O3-NO were observed. Meanwhile, the size distributions and mass concentrations of SOA were monitored with a scanning mobility particle sizer (SMPS) during the formation processes. The rapid exponential growths of SOA reveal that the atmospheric lifetimes of gas-phase anthracene towards O3 and O3-NO are less than 20.5 and 4.34 hr, respectively. The particulate oxidation products from homogeneous and heterogeneous reactions were analyzed with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). Gas chromatograph/mass spectrometer (GC/MS) analyses of oxidation products of anthracene were carried out for assigning the time-of-flight (TOF) mass spectra of products from homogeneous and heterogeneous reactions. Anthrone, anthraquinone, 9,10- dihydroxyanthracene, and 1,9,10-trihydroxyanthracene were the ozonation products of anthracene, while anthrone, anthraquinone, 9-nitroanthracene, and 1,8-dihydroxyanthraquinone were the main products of anthracene with O3-NO.     

基于单颗粒质谱信息气溶胶分类方法的研究进展

气溶胶质谱仪在对气溶胶颗粒的监测过程中会产生大量单颗粒的化学成分和粒径信息,基于这些质谱数据能够推测颗粒的来源。而对气溶胶来源的分析,很大程度上是由颗粒的种类决定的,故对海量数据的分类就成为不可忽略的步骤。针对气溶胶质谱仪采集到的数据,概述了用于气溶胶分类的多种方法的理论核心、分类步骤及各自的优缺点等。据此可为今后气溶胶分类方法的研究提供建设性意见。     

分光光度法中不同光程长度比色皿间关系验证

参照《纳氏试剂分光光度法》的方法原理,用分光光度计对3种光程长度比色皿分别进行比色,探讨不同光程长度比色皿间关系。     

Application of CGP-cross route process for microstructure refinement and mechanical properties improvement in steel sheets

A modified method of severe plastic deformation (SPD) entitled constrained groove pressing-cross route (CGP-CR) was introduced for imposing a high magnitude of equivalent strain of about 2.32 per pass on the sheet form samples. The major benefit of this improved route compared to previous common route was the more homogeneity of strain in the rolling (RD) and transverse (TD) directions of sheets. In this study, low carbon steel samples were used for examination of evolutions in microstructure and mechanical properties during SPD via CGP-CR process. Mechanical properties improvement were measured by tensile and macro hardness tests. The results indicate that CGP-CR process can effectively improve tensile strength; and also, yield stress and hardness of as-received low carbon steel samples were improved up to about 100% after two deformation passes. Also, high magnitude of inhomogeneity can be observed in hardness distribution through first pass of the process which diminishes in the subsequent passes. Microstructural evolutions during process were monitored by optical microscopy observations and X-ray diffraction analysis. The results demonstrate that initial ferritic microstructure with grain size of about 30 μm was refined to a 225 nm cell structure after two passes of CGP-CR process.     

航空光学器件的损伤破裂机理和加速寿命试验方法 研究

目的研究航空光学器件的损伤破裂机理和加速寿命试验方法。方法从理论上对航空光学器件的损伤破裂机理进行研究,对不同机理产生的原因、表现及预防措施进行分析。分析大气摩擦和太阳辐射因素对航空光学器件表面温度的影响,在Arrhenius模型理论基础上,以加速寿命试验方法计算航空光学器件的寿命。结果推导出了航空光学器件寿命的计算公式。结论航空光学器件的损伤破裂主要归因于脆性断裂失效和疲劳断裂失效。