泥炭树脂颗粒对水溶液中十二烷基苯磺酸钠的去除

泥炭树脂颗粒对水溶液中十二烷基苯磺酸钠 (SDBS)具有很好的去除效果。数据分析表明 ,Freundlich和 Langmuir吸附等温方程可以很好地描述这一过程。通过 L angmuir方程计算出颗粒对 SDBS的最大吸附量为 3 3 .3 3 mg·g- 1。在试验条件下 ,吸附量随着 SDBS的初始浓度增加而增加 ,当溶液的初始 p H在 4～ 8的范围时 ,颗粒对 SDBS吸附量变化很小。溶液的初始浓度对吸附速率产生明显影响 ,浓度越低吸附速率越快 ,达到吸附平衡所需的时间越短。准二级动力学模型能够很好地描述颗粒对 SDBS的吸附过程。     

大气微生物粒子与飘尘粒子的关系

用ＡＮＤＥＲＳＥＮ生物粒子采样器和光散射气溶胶粒子计数器，在北京西单对大气细菌、真菌和飘尘粒子的浓度、粒度分布及它们之间的关系进行了观测和研究。结果表明，大气细菌的粒度是负偏态分布，大气真菌是对数正态分布，飘尘是正偏态分布。大气细菌浓度与飘尘浓度的比值冬季大，为１１９５３８；夏季小，为２４２１７；年平均比值为６７５１７，＞２．０μｍ的菌尘比值为１５２５３８７，２．０μｍ～８．２μｍ的菌尘比值为３３１８，＞８．２μｍ的菌尘比值为３９４。大气真菌浓度与飘尘浓度的比值冬季大，为２１２７７０；夏季小，为６５５８５；年平均比值为１３５３４４，＜２．０μｍ的菌尘比值为９５２６９８，２．０μｍ～８．２μｍ的菌尘比值为５３４３，＞８．２μｍ的菌尘比值为２６３２。     

Stratification and Tidal Current Effects on Larval Transport in the Eastern English Channel: Observations and 3D Modeling

We study how the combination of tides and freshwater buoyancy affects the marine organisms accumulation and horizontal transport in the ROFI system of the eastern English Channel. The Princeton Ocean Model coupled with a particle-tracking module is used to study the migration of fish eggs and larvae under different forcing conditions. Results of modeling are validated against observed concentrations of Flounder (Pleuronectes flesus) larvae. Numerical Lagrangian tracking experiments are performed with passive and active particles, representing sea-water organisms. Passive particles are neutrally buoyant whereas active particles are able to exercise light dependent vertical migrations equating to the swimming behavior of larvae. The experiments reveal that the strongest accumulation of particles occurs along the French coast on the margin of the ROFI. This happens because the interaction between the turbulence, the freshwater buoyancy input, and tidal dynamics, produces particle trapping and vertical spreading within the frontal convergence zone. Tides and freshwater input induce net alongshore horizontal transport toward the North. Tidal currents modulate the magnitude of horizontal transport whereas the fresh water input controls more the location of accumulation zones. Tracking experiments with active particles indicate that the vertical migration leads to a significant departure from the passive particle transport pattern. Differences lie in the shape of the particle transport pattern and the rate of the northward migration. In particular, vertically migrating particles travel slower. To find possible Flounder migration pathways, particles are released within the assumed spawning area of Flounder. The model predicts larvae drift routes and demonstrates that throughout the entire particle-tracking period the horizontal structure of the particle distribution is consistent with the larvae concentrations observed during the field experiments.     

近海海洋大气颗粒物中元素浓度及粒径分布研究

本工作用质子激发Ｘ荧光分析光测定近中国海域上空不同粒径大气颗粒物中１４个元素的浓度、粒径分布及富集因子。研究发现，在开阔海域大气污染元素和地壳元素主要来自亚洲大陆长距离输送的贡献，海水元素浓度受海盐气溶胶的控制，估算近中国海域大气中的尘土量为０．４－２．３μｇ／ｍ＾３，尘土粒子的输入量控制着海洋大气颗粒物中地壳元素浓度。     

渤海非色素颗粒物和黄色物质的吸收特性研究

非色素颗粒物和黄色物质的吸收是海水总吸收系数中重要的组成部分,也是海洋光学和水色遥感目前主要的研究内容.本文利用2005年测量的渤海黄色物质与非色素颗粒物的吸收系数,回归了两者吸收系数的曲线斜率,平均值分别为0.012和0.014 nm-1,这与国外测量的结果是一致的;分析了吸收系数和曲线斜率的时空分布,发现两者存在比较明显的负相关关系,可能是由于非色素颗粒物与黄色物质的两种来源导致的.     

城市雾天单个矿物颗粒物理和化学特征

应用场发射扫描电镜(FESEM)和带能谱的扫描电镜(SEM-EDX)对北京冬季雾天和正常天气下收集的4个样品进行研究.雾天中矿物颗粒的数量-粒度分布的峰值出现在0.1～0.3 μm和1～2.5 μm之间,并且发现雾天出现的二次矿物颗粒的数量百分含量(4.67%)高于正常天气条件(0.12%).单个矿物颗粒的EDX能谱显示,雾天和正常天气中单个矿物颗粒的主要化学成分有一定的差别,尤其是S元素.矿物颗粒分为9种不同类型:"富Si"、"富Ca"、"富S"、"富Fe""富Mg"、"富Al"、"富Ti"、"富K"和"富Cl",其中雾天"富Ca"中55%的颗粒含有Ca(50%±1.2%)和S(37%±1.6%),"富S"中72%的颗粒含有S(44%±1.5%)和Ca(33%±2%),说明了雾天中绝大部富集S的颗粒物中同时富集Ca,这在一定程度上说明了北京市大气中这些含Ca的碱性矿物对雾水酸性有一定的缓冲作用.雾天样品中S/Ca的平均比值为6.11,如果以冬季正常天气条件下S/Ca的均值0.73为背景值,雾天中S/Ca的比值是冬季正常天气的8倍,可见雾天中颗粒物表面的硫化现象相当严重,同时也显示出雾天SO2向硫酸盐的转化率比较高.     

特厚倾斜煤层采空区对公路路基沉降影响研究

为了研究采空区导致上覆复杂岩层运移致使公路路基沉降问题,以颗粒流理论为基础,通过下落法构建模型。根据煤层位置,假设了7种采空区长度进行模拟。模拟的结果为岩层应力、应变在不同情况下的最终状态,同时提出了影响区和松散堆积区的概念。结果表明,由于岩层构造复杂,在不同情况下主要影响区和松散堆积区的发展变化是不同的,特别是岩层4的作用较为特殊。根据公路路基设计规范,采空区只限于假设1和假设2的采空区范围内,路基沉降才能满足规范要求。     

Comparison of light absorption and oxidative potential of biodiesel/diesel and chemicals/diesel blends soot particles

Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health outcomes.Though biodiesel or additives blending with diesel was considered environmentally friendly,the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear.The watersoluble organic carbon(WSOC) content,surface chemical structure,light absorption and oxidative potential(OP~(DTT)) of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer,X-ray photoelectron spectrometer,ultraviolet–visible spectrophotometry and dithiothreitol(DTT) assay.The differences and correlations between soot properties were statistically analyzed.Chemicals/diesel blends soot owned significantly higher WSOC content,ratio of mass absorbing efficiency(MAE) in250 and 365 nm(E_2/E_3),OP~(DTT),and higher surface carbonyl content.Coconut biodiesel/diesel blends soot contained evidently higher aromatic carbon–oxygen single bond(Ar_C–O)content,and higher MAE365.The individual comparison of biodiesel/diesel blends showed20% coconut biodiesel blend owned the lowest WSOC,E_2/E_3 and OP~(DTT),while highest Ar_C–O and MAE365,representing strongest absorbing properties.Association analysis showed OP~(DTT)was significantly positively correlated with WSOC.Further,the evident negative correlation between MAE365 and OP~(DTT) was observed.Our results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential,whereas absorption of light was higher,which have far reaching consequences on climate forcing.Therefore,it is important to evaluate the balance point between light-absorbing properties and oxidative potential,under the wide use of biodiesel.     

微/纳米颗粒表面能测定方法适用性研究

采用静态液滴法、柱毛细法、板毛细法3种方法,分别测定了水、正己烷、甲酰胺、二碘甲烷4种液体与TiO_2(40 nm)、TiO_2(100 nm)、Al_2O_3(200 nm)、高岭土(200~400nm)、Fe_2O_3(400~600 nm)、SiO_2(20μm)6种粒径微/纳米颗粒之间的接触角,确定了适用于不同颗粒粒径的接触角测定方法.在此基础之上,利用Young-Dupré方程计算了各微/纳米颗粒的表面能及各分项.结果表明:粒径较小的颗粒(如200 nm)接触角的测定适合使用静态液滴法,而粒径较大的颗粒(如600 nm)接触角的测定适合使用柱毛细法.粒径大小适中时(如200~600 nm),静态液滴法和柱毛细法都适用,测定结果差别普遍较小(≤11°),但二碘甲烷与Fe_2O_3(400~600 nm)之间的接触角利用不同方法测定结果相差可达14°.静态液滴法操作方便,但由于粗糙度的影响需要对接触角测定值进行修正.板毛细法测定接触角时,液体容易挥发,不易得到准确测量结果,不推荐使用.对全部6种测定的微/纳米颗粒,表面能的计算结果相差不大.表面能的3个分项中,范德华分量(γLW)与路易斯碱分量(γ-)的贡献最大,路易斯酸分量(γ+)的贡献很小,主要是因为在微/纳米颗粒-液体界面中,电子受体的反应活性较低.     

POC的结构参数对DMCC发动机排放影响的试验研究

在一台直列4缸增压中冷电控单体泵柴油机的进气道上增加甲醇喷射装置,实现柴油甲醇二元燃料燃烧(DMDF)模式.利用废气分析仪对其主要气体排放进行测量,研究在排气管上加装的柴油颗粒氧化催化转化器结构参数对尾气催化效率的影响,试验结果表明:POC长度越长,对碳烟、THC、和未燃甲醇的转化效果越好,甲醇替代率为30%、POC长度为100 mm时,对碳烟、CO、THC和未燃甲醇的平均净化效率分别为15.00%、91.61%、75.56%、66.96%,长度增加至200 mm后,上述效率明显提高,分别提高到30.37%、99.29%、67.55%、95.44%;POC孔密度增加,POC对碳烟、CO及未燃甲醇的转化效率有小幅增加,甲醇替代率为30%时,孔密度从200目增加到300目,对碳烟、CO和未燃甲醇的催化效率分别从19.61%、94.66%、86.07%提高到23.06%、97.44%和88.56%;POC结构参数的改变对NO_x的转化效率影响不大.