环胶州湾河流入海口CDOM吸收光谱特征

为深入认识河流对胶州湾水体有机碳的贡献,于2016年4月-2017年2月对环胶州湾河流入海口进行双月采样,通过分析水体中DOC（溶解有机碳）和POC（颗粒有机碳）质量浓度及CDOM（有色溶解有机物）的吸收光谱特征,揭示环胶州湾入海口有机碳的分布特征,辨析CDOM的组成和来源,探讨其与主要环境因素的关系.结果表明:①环胶州湾河流入海口DOC和POC质量浓度范围分别为0.98~32.75和0.13~22.40 mg/L,其中李村河口最高,轮渡和大港相对较小.②a（355）（CDOM的吸收系数）变化范围为0.23~16.35 m-1,存在明显的季节性差异,与盐度成反比,其分布与DOC和POC基本一致.③研究区域水体中,表征CDOM分子组成、来源及芳香化程度的S_R[光谱斜率比,S_g（275~295 nm）/S_g（350~400 nm）]和A_{250 nm}/A_{365 nm}存在显著的时空差异.④夏季、秋季CDOM的整体分子量水平高于春季、冬季;轮渡、大港、板桥坊河和娄山河S_R相对较高,CDOM组成趋向于蛋白类或富里酸类物质.⑤轮渡、大港和镰湾河A_{250 nm}/A_{365 nm}相对较高,类腐殖质的芳香化程度较低,受海源控制;其他河口A_{250 nm}/A_{365 nm}相对较低,CDOM以陆源输入为主,其类腐殖质的芳香化程度较高,结构相对稳定而不易降解.⑥CCA（Canonical Correspond Analysis,典范对应分析）结果表明,DOC与CDOM吸收特性存在较好的相关性,河口CDOM主要来自地表径流,温度和DO是影响CDOM时空分布的主要因素.研究显示,CDOM的组成、降解的难易程度与来源密切相关,秋季生物量丰富,水体中腐殖酸所占比例增大,CDOM芳香度较高,不容易被降解.      

桂林五里峡水库丰水期溶解有机碳特征

为更全面、准确把握岩溶碳循环特征,本文在获取桂林五里峡水库丰水期水化学及溶解有机碳(DOC)分布特征的基础上,还借助紫外吸收光谱技术对水体有机质分子量大小等进行分析.结果表明,五里峡水库丰水期水化学类型仍为HCO_3-Ca·Mg型,水体营养状态为中等营养型,未达到富营养状态;五里峡水库丰水期DOC质量浓度比枯水期低,DOC为TOC的主要组成部分,DOC质量浓度在垂直方向上呈表层至底层降低的趋势,这是Chl-a、DIC等水环境因子综合影响的结果;S_(275~295)、M、SUVA_(254)、E_(253)/E_(203)吸收光谱特征参数表征下的库区水体有机质以小分子量物质为主,富里酸所占比例高,腐殖酸所占比例低,芳香性较弱,苯环上脂肪族等非极性官能团含量较多,表明库区水体DOC内源特征较强,有机质生物活性较好,在水库碳循环中发挥了积极作用.     

东平湖CDOM吸收光谱特性及其来源解析

为分析东平湖有色可溶性有机物（CDOM）吸收特性、来源和空间分布的季节变化,分别于2013年8、12月以及2014年3月采集了35个表层水样,分析了各基本水质参数、CDOM吸收系数[a（440）]、比吸收系数[a^*（440）]和相对分子量参数M值的分布规律及CDOM吸收系数与水质参数之间的相关关系.结果表明：东平湖CDOM吸收系数a（440）呈现出枯水期 > 丰水期 > 平水期的规律,空间分布与CDOM比吸收系数[a^*（440）]相似.M值呈现出丰水期 < 平水期 < 枯水期的变化趋势.丰水期CDOM吸收系数与叶绿素a（Chla）具有显著相关关系;丰、平水期两季CDOM吸收系数与DOC存在显著相关关系.丰水期CDOM同时受外源和内源输入的影响,但以内源输入为主,主要来源于浮游植物降解产物;老湖镇湖区外源特征明显.平水期CDOM亦受内源和外源输入的双重影响,但浮游植物的腐烂降解不是CDOM的主要来源;北部湖区以外源输入为主.枯水期CDOM整体表现出较强的自生源特征,但相关分析显示,浮游植物降解并不是CDOM的主要来源,自生源特征可能与挖沙活动导致的悬浮物浓度增高有关;东南湖区因大汶河输入的影响呈现出较强的外源特征.利用东平湖丰、平水期两季CDOM浓度反演DOC浓度具有可行性.     

金属矿山掘进巷道新型通风除尘系统研究与应用

为了减少掘进巷道的粉尘危害,以某金属矿掘进工作面为研究对象,经过现场调研和理论分析,研究开发了1种适合掘进巷道的新型通风除尘系统。介绍了新型通风除尘系统的结构和工作原理,并将该通风除尘系统应用于掘进巷道的粉尘治理,对该系统在掘进巷道的应用效果进行现场测定。研究结果表明:该通风除尘系统将压风筒布置在巷道中心位置的顶部,抽风筒布置在巷道两侧的呼吸带高度,使得掘进工作面的风流位置控制在1.5 m之下,保障了作业人员的职业健康。系统的湿式除尘风机对掘进巷道粉尘除尘效率达到了91%以上,彻底解决了掘进巷道粉尘污染问题。同时该系统能够实现按需通风除尘,净化后的风流可以循环利用,节能效果显著,在金属矿山掘进巷道生产系统具有较好的应用前景。     

膜参数对膜吸收法天然气脱硫传质性能的影响研究

以N-甲基二乙醇胺(MDEA)溶液为吸收液,采用膜吸收法进行了模拟天然气脱硫试验,考察了不同膜参数对MDEA溶液脱硫过程中传质性能的影响。结果表明:在较为理想的稳态膜吸收过程中,多孔膜孔径大小、膜厚度以及膜孔形态等因素对稳态膜吸收过程中的传质效果影响不大;在其他条件不变的情况下,多孔膜的传质性能随着孔隙率的增大而提高;同时传质效果还受到膜润湿现象的影响。这说明在较为理想的稳态膜吸收过程中孔隙率是对传质效果产生影响的主要因素,为膜吸收过程传质的影响因素探究及多孔膜选择提供了依据。     

Oxidation state specific analysis of arsenic species in tissues of wild-type and arsenic (+ 3 oxidation state) methyltransferase-knockout mice

Arsenic methyltransferase(As3mt) catalyzes the conversion of inorganic arsenic(i As) to its methylated metabolites, including toxic methylarsonite(MAs~Ⅲ) and dimethylarsinite(DMAs~Ⅲ). Knockout(KO) of As3 mt was shown to reduce the capacity to methylate i As in mice. However, no data are available on the oxidation states of As species in tissues of these mice. Here, we compare the oxidation states of As species in tissues of male C57BL/6 As3mt-KO and wild-type(WT) mice exposed to arsenite(iA s~Ⅲ) in drinking water. WT mice were exposed to50 mg/L As and As3mt-KO mice that cannot tolerate 50 mg/L As were exposed to 0, 15, 20, 25 or30 mg/L As. iA s~Ⅲaccounted for 53% to 74% of total As in liver, pancreas, adipose, lung, heart, and kidney of As3mt-KO mice; tri- and pentavalent methylated arsenicals did not exceed 10% of total As. Tissues of WT mice retained iA s and methylated arsenicals: iA s~Ⅲ, MAs~Ⅲand DMAs~Ⅲ represented 55%‐68% of the total As in the liver, pancreas, and brain. High levels of methylated species, particularly MAs~Ⅲ, were found in the intestine of WT, but not As3mt-KO mice,suggesting that intestinal bacteria are not a major source of methylated As. Blood of WT mice contained significantly higher levels of As than blood of As3mt-KO mice. This study is the first to determine oxidation states of As species in tissues of As3mt-KO mice. Results will help to design studies using WT and As3mt-KO mice to examine the role of iA s methylation in adverse effects of iA s exposure.     

Effectiveness of terrestrial protected areas for conservation of lake fish communities

Freshwater protected areas are rare even though freshwater ecosystems are among the most imperiled in the world. Conservation actions within terrestrial protected areas (TPAs) such as development or resource extraction regulations may spill over to benefit freshwater ecosystems within their boundaries. Using data from 175 lakes across Ontario, Canada, we compared common indicators of fish‐assemblage status (i.e., species richness, Shannon diversity index, catch per unit effort, and normalized‐length size spectrum slopes) to evaluate whether TPAs benefit lake fish assemblages. Nearest neighbor cluster analysis was used to generate pairs of lakes: inside versus outside, inside versus bordering, and bordering versus outside TPAs based on lake characteristics. The diversity and abundance indicators did not differ significantly across comparisons, but normalized‐length size spectrum slopes (NLSS) were significantly steeper in lakes outside parks. The latter indicated assemblage differences (greater abundances of small‐bodied species) and less‐efficient energy transfer through the trophic levels of assemblages outside parks. Although not significantly different, pollution‐ and turbidity‐tolerant species were more abundant outside parks, whereas 3 of the 4 pollution‐intolerant species were more abundant within parks. Twenty‐one percent of the difference in slopes was related to higher total dissolved solids concentrations and angling pressure. Our results support the hypothesis that TPAs benefit lake fish assemblages and suggest that NLSS slopes are informative indicators for aquatic protected area evaluations because they represent compositional and functional aspects of communities.     

Effects of hexachlorocyclohexane administration on distribution of trace metals in rat tissues

The effects of daily administration of hexachlorocyclohexane (HCH) for 90 days on the distribution of Cu, Zn, Fe and Mn in rat tissues were investigated. The results indicated that HCH caused a significant increase in weight of liver and spleen and decrease in the weight of kidney, heart and brain. The spleen and heart demonstrated the maximum mobilization of metals. Comparing the individual trace elements, zinc appeared to be the most active element. None of the metals assayed registered change in RBC's but there was increase in Zn, Fe and Mn concentration in plasma.     

The effect of fluorescent tracers on droplet spectrum,viscosity, and density of pesticide formulations

The most important factor affecting efficacy and drift of pesticide applications is the droplet spectrum. To measure pesticide drift, researchers utilize fluorescent tracers to rapidly quantify spray deposition. Although fluorescent tracers have been used for more than 50 years, no experiments have been performed on the effect they have on the properties of pesticide formulations (density and viscosity) or droplet spectrum, which affect the drift of pesticides. Therefore, we examined the effect of an oil- and water-based tracer on the volume median diameter (VMD), viscosity, and density of oil- and water-based pesticide formulations. In addition, we experimentally fit and demonstrate the utility of using distributions to characterize pesticide droplet spectra. The addition of tracers to both water- and oil-based formulations did not significantly alter the VMD, viscosity, and density. Lognormal distributions provided the best fit for the water- and oil-based formulations with and without tracer. Our results demonstrated that the addition of oil- and water-based tracers do not significantly alter pesticide formulations properties and droplet spectrum, and most likely do not alter the movement of pesticide droplets in the environment.     

Preparation and luminescence properties of Zn3 （BO3）2 doped with Ce3＋and Mn2＋

采用共沉淀法在700℃和较短的烧结时间下制备了Zn3（BO3）2和不同浓度的Ce3＋、Mn2＋离子掺杂的Zn3（BO3）2纳米晶粉末,对合成产物的发光性质及发光机理进行了研究。利用荧光分光光度计、X射线粉末衍射仪以及透射电镜对其光学性能和纳米晶形貌进行了表征。结果表明Ce3＋离子掺杂的Zn3（BO3）2样品在340～400nm之间有强的荧光发射,其最高发射峰峰位为365nm,在Ce3＋掺量为0.5%（摩尔分数,下同）时发光强度达到最高值。Ce3＋取代Zn2＋离子作为发光中心,Mn2＋离子作为激活剂加入,并不影响荧光发射峰的位置,但能够有效增强其发光强度。当Mn2＋离子掺量为0.7%（摩尔分数）时,Ce3＋、Mn2＋共掺杂的Zn3（BO3）2纳米晶发光强度达到最高值。