Red spruce canopy response to acid fog exposure     

Richard Jagels  Mei Jiang  Susan Marden  Jonathan Carlisle 《Atmospheric Research》2002,64(1-4)

The health of red spruce is adversely affected by exposure to acid fog. Epicuticular wax structure over epistomatal chambers, mesophyll membrane calcium and changes in redox state of glutathione are affected in both chamber and field studies and are correlated with leaf exposure to acid fog, but not with soil or total leaf calcium concentrations. Experiments tracking fog deposition under conditions of illumination or darkness, with or without a metabolic inhibitor, support the mechanism of diffusiophoresis linked with photosynthetic gas exchange. Based on deposition pattern and leaf morphology, a stomatal pathway for water and hydrogen ion penetration to leaf interior is proposed. Ecophysiological parameters are discussed in relation to differential sensitivities of red spruce and white pine to ozone and acid fog.  相似文献   

用于多接收器等离子体质谱测定的铁铜锌同位素标准溶液研制   总被引：3，自引：3，他引：0  

唐索寒  朱祥坤  李津  闫斌  李世珍  李志红  王跃  孙剑 《岩矿测试》2016,35(2):127-133

近十来年铁铜锌同位素研究已经成为热门研究领域,铁铜锌同位素分析方法日趋成熟,但是铁铜锌同位素标准物质却十分匮乏。目前欧盟参考物质及测量研究所(IRMM)有1个铁同位素标准物质和1个锌同位素标准物质,前者售罄,后者价格昂贵;美国国家标准局(NIST)有1个铜同位素标准物质。为了适应我国铁铜锌同位素研究的发展,本文使用铁铜锌元素浓度标准溶液作为备选标准溶液研制了铁铜锌三个同位素标准溶液(CAGS-Fe、CAGS-Cu和CAGS-Zn)。三个备选标准溶液经过F检验均匀性良好;在38个月内δ56Fe、δ57Fe、δ65Cu、δ66Zn和δ68Zn值没有显著性变化,具有良好的稳定性;主要特性值的推荐值及95%置信水平的不确定度为:CAGS-Fe,δ56FeIRMM014(‰)=0.80±0.05,δ57FeIRMM014(‰)=1.20±0.10;CAGS-Cu,δ65CuIRMM976(‰)=0.57±0.06;CAGS-Zn,δ66ZnIRMM3702(‰)=-0.77±0.10,δ68ZnIRMM3702(‰)=-1.55±0.13。本文研制的标准溶液可用于多接收器等离子体质谱仪测定铁铜锌同位素时的仪器校正和质谱分析过程监控,对于不同实验室的测试数据对比具有重要意义。  相似文献   

乌贼墨黑色素对铅中毒小鼠的排铅作用及其对体内钙、锌和铜含量的影响     

吕玲  李和生  郑丽  李密  金洋 《海洋与湖沼》2016,47(2):484-490

本文研究了乌贼墨黑色素对铅中毒小鼠的排铅作用及对小鼠体内钙、锌和铜含量的影响。采用48只小鼠为实验对象,按体质量随机分为阴性对照组,醋酸铅模型对照组,乌贼墨黑色素低(50mg/kg)、中(100mg/kg)、高(200mg/kg)剂量组以及阳性对照组(1.5g/60 kg),除阴性对照组外其余各组均每天腹腔注射醋酸铅溶液(7mg/kg)10天。第11天起各剂量组用乌贼墨黑色素灌胃,阴性对照组及醋酸铅模型对照组灌胃去离子水,阳性对照组灌胃二巯基丁二酸(DMSA),连续进行28d。采用原子吸收分光光度法测定小鼠的血液、肝、肾及脑组织中的铅、钙、锌和铜的含量。研究发现乌贼墨黑色素高剂量组(200mg/kg)显著降低了血铅含量,下降28.15%;乌贼墨黑色素中剂量组(100mg/kg)显著降低了肝铅含量,下降15.89%。同时,乌贼墨黑色素高剂量组对铅中毒小鼠肝铜、肾锌以及脑锌的含量高于醋酸铅模型对照组(P0.05),而与阴性对照组相比无统计学差异(P0.05)。以上结果表明高剂量、中剂量乌贼墨黑色素对血铅与肝铅有一定的排铅作用,同时高剂量的乌贼墨黑色素对小鼠肝脏中的铜、肾脏中的锌以及脑中的锌有保护作用。  相似文献   

青海省冷湖镇钾矿资源调查评价项目冲洗液技术研究及应用          下载免费PDF全文

纪卫军  张明德  赵长亮  张磊  付帆  鲁生彪 《探矿工程》2016,43(1):54-57

青海省冷湖镇钾矿资源调查评价项目要求对冷湖镇地区开展钾矿资源调查评价。青海省冷湖镇地区地层中含有大段石盐和石膏层,而且地层松散、压力系数大。针对该地区的特殊情况,研制了不分散抗盐防塌冲洗液。应用表明,该冲洗液具备较好的抗盐抗钙能力、防塌性和悬浮性,并且应根据地层压力系数不同来调节冲洗液的密度。  相似文献   

江陵凹陷南缘盐井-申津渡凹地始新统硫同位素特征及古气候和物质来源探讨     

颜开  刘成林  王九一  王春连  徐海明  王春林  余小灿  孟令阳 《地质学报》2018,92(8):1647-1660

江陵凹陷南缘盐井-申津渡凹地的早始新世新沟嘴组发育一套钙芒硝-石盐的蒸发岩系地层。岩相学和矿物学证据显示,含盐系地层的主要盐类矿物包括石盐、钙芒硝、硬石膏,形成于常年性的盐湖环境中。钙芒硝为原生-准同生的盐类矿物。根据盐类矿物的类型和沉积特征以及典型暖相盐类矿物(原生钙芒硝)的广泛发育,推断出盐井-申津渡凹地在新沟嘴组沉积时期的古气候为暖型。钙芒硝δ~(34)S组成为25‰~33‰,高于同时期海水硫同位素(17‰~19‰),可能经受过细菌改造。除此之外,晚古新世-早始新世时,盐井-申津渡凹地的硫酸盐物质也有可能来源于西部较老时期的含硫酸盐地层。  相似文献   

Calcium Carbonate and Phosphate Reference Materials for Monitoring Bulk and Microanalytical Determination of Sr Isotopes          下载免费PDF全文

Michael Weber  Federico Lugli  Klaus Peter Jochum  Anna Cipriani  Denis Scholz 《Geostandards and Geoanalytical Research》2018,42(1):77-89

In situ laser ablation analyses rely on the microanalytical homogeneity of reference materials (RMs) and a similar matrix and mass fraction between unknown samples and RMs to obtain reliable results. Suitable carbonate and phosphate RMs for determination of Sr isotope ratios in such materials are limited. Thus, we determined ⁸⁷Sr/⁸⁶Sr ratios of several carbonate (JCt‐1, JCp‐1, MACS‐1, MACS‐3) and phosphate (MAPS‐4, MAPS‐5, NIST SRM 1400, NIST SRM 1486) international RMs using dissolved samples and two different multi‐collector inductively coupled plasma‐mass spectrometers (MC‐ICP‐MS). Our Sr isotope data are in agreement with published data and have an improved measurement precision for some RMs. For MACS‐1, we present the first ⁸⁷Sr/⁸⁶Sr value. We tested the suitability of these materials for microanalytical analyses by LA‐MC‐ICP‐MS, with two different laser ablation systems: a conventional nanosecond laser and a state‐of‐the‐art femtosecond laser. We investigated the RMs micro‐homogeneity and compared the data with our solution data. Both laser ablation systems yielded identical ⁸⁷Sr/⁸⁶Sr ratios within uncertainty to the solution data for RMs with low interferences of REEs. Therefore, these carbonate and phosphate RMs can be used to achieve accurate and precise results for in situ Sr isotope investigations by LA‐MC‐ICP‐MS of similar materials.  相似文献   

室温条件下青海湖水中镁离子浓度对沉淀碳酸钙同质多像类型的调控     

杨康  李红  雷云  牛元哲  冯诗海 《岩石矿物学杂志》2021,40(3):571-580

青海湖是我国唯一报道过的现代湖底沉积物中白云石、方解石和文石等多种碳酸盐矿物共存的高原内陆咸水湖泊。以青海湖水和除菌青海湖水作为载体,以CaCl_2和MgCl_2·6 H_2O作为反应原料,在实验室常温条件下采取控制变量法制备出不同浓度Mg~(2+)参与下的钙质沉淀物,探讨Mg~(2+)浓度对沉淀物类型的影响。仅添加CaCl_2时,青海湖水中的沉淀物主要是石膏(Ca SO_4·2 H_2O)和球霰石(CaCO_3);在添加CaCl_2的同时添加MgCl_2·6 H_2O,沉淀物的石膏消失,完全转变成碳酸盐矿物,包括方解石和球霰石;当湖水中Mg~(2+)浓度为0.62 mol/L时,球霰石消失,沉淀物变为方解石和文石;随着Mg~(2+)浓度继续升高,文石含量稳步增加,方解石含量则逐渐减少,当Mg~(2+)浓度达到1.22 mol/L或更高时,方解石全部消失,沉淀物仅剩文石。实验结果表明,青海湖水中较高浓度的SO_4~(2-)对碳酸钙晶体生长有抑制作用,而额外加入的Mg~(2+)可以解除SO_4~(2-)的抑制作用,使得Ca~(2+)与HCO_3~-和CO_3~(2-)结合形成碳酸钙。此外,碳酸钙的同质多像类型也明显受到Mg~(2+)浓度的控制,随着湖水中Mg~(2+)浓度增加,方解石、球霰石不再稳定,而文石逐渐占主导地位,当Mg/Ca值达到6.1时,反应产物中仅有文石稳定存在。  相似文献   

Study of diclofenac removal by the application of combined zero-valent iron and calcium peroxide nanoparticles in groundwater          下载免费PDF全文

Liang Wen  Zhou Nian-qing  Dai Chao-meng  Duan Yan-ping  Zhou Lang  Tu Yao-jen 《地下水科学与工程》2021,9(3):171-180

Diclofenac(DCF) is one of the most frequently detected pharmaceuticals in groundwater, posing a great threat to the environment and human health due to its toxicity. To mitigate the DCF contamination,experiments on DCF degradation by the combined process of zero-valent iron nanoparticles(nZVI) and nano calcium peroxide(nCaO_2) were performed. A batch experiment was conducted to examine the influence of the adding dosages of both nZVI and nCaO_2 nanoparticles and pH value on the DCF removal.In the meantime, the continuous-flow experiment was done to explore the sustainability of the DCF degradation by jointly adding nZVI/nCaO_2 nanoparticles in the reaction system. The results show that the nZVI/nCaO_2 can effectively remove the DCF in the batch test with only 0.05 g/L nZVI and 0.2 g/L nCaO_2 added, resulting in a removal rate of greater than 90% in a 2-hour reaction with an initial pH of 5. The degradation rate of DCF was positively correlated with the dosage of nCaO_2, and negatively correlated with both nZVI dosage and the initial pH value. The order of significance of the three factors is identified as pH value nZVI dosage nCaO_2 dosage. In the continuous-flow reaction system, the DCF removal rates remained above 75% within 150 minutes at the pH of 5, with the applied dosages of 0.5 g/L for nZVI and 1.0 g/L for nCaO_2. These results provide a theoretical basis for the nZVI/nCaO_2 application to remove DCF in groundwater.  相似文献   

Behaviour of boron,calcium and magnesium in a polluted estuary     

P.V. Narvekar  M.D. Zingde  V.N. Kamat Dalal 《Estuarine, Coastal and Shelf Science》1983,16(1):9-16

Behaviour of industrially added boron in the well mixed Ambika river estuary of South Gujarat, India has been studied along with that of calcium and magnesium. The ratios of Ca : Cl and Mg : Cl at varying chlorinities were always within the normal ranges found in river water at one end and seawater at the other end. B : Cl exceeded the river water end limit at the ebb tide at an upstream station. Percentage addition or removal of boron, calcium and magnesium was calculated using the concept of the theoretical dilution line. The external input raised the boron concentration by 263% in the vicinity of the industrial discharge. A correlation coefficient of ?0·82 between chlorinity and percentage addition or removal of boron supports the theory of boron incorporation in sediments in amounts proportional to salinity. Inverse relationship between percentage addition or removal of boron and suspended solids was observed. Behaviour of calcium and magnesium was in line with the replacement of Ca²⁺ ions occupying the majority of ion-exchange sites in riverine clays by Mg²⁺, Na⁺ and K⁺ during their first encounter with seawater.  相似文献   

粉石英在微孔硅酸钙保温材料中的应用研究   总被引：3，自引：0，他引：3  

余志伟 《华东地质学院学报》1997,20(3):233-244

本文介绍了一种新的优质硅质原料－－粉石英，着重探讨了它的矿物组成、粒度分布、物化性质及其合成硅酸钙的试验。试验结果表明，粉石英与石在高温、高压和搅拌的条件下，可以合成硅硅钙石型优质微孔硅酸钙制品。为微孔硅酸钙行业开发了一种新的质优、价廉的硅质原料。  相似文献