2009年天津城区空气负离子变化规律   总被引：2，自引：0，他引：2       下载免费PDF全文

孟丽红  张敏  姚青 《气象与环境学报》2011,27(1):27-29

空气负离子成为空气清洁度的重要评价指标。利用2009年天津城区空气负离子观测数据,研究天津城区空气负离子的时空变化规律。结果表明：天津城区空气负离子月变化浓度呈双峰型分布,主峰值出现在9月,次峰值出现在5月,7月份负离子浓度最低;四个季节中负离子的日变化特征存在明显差异;天津市和大连市两个沿海城市的负离子浓度范围相差不大,最低值均出现在7月份,但二者月变化规律趋势不同。  相似文献   

Migration of total chromium and chloride anion in the Rocha River used for estimating degradation of agricultural soil quality at the Thiu Rancho zone          下载免费PDF全文

Terrazas-Salvatierra Jhim  Munoz-Vásquez Galo  Romero-Jaldin Ana 《地下水科学与工程》2020,8(3):223-229

The Rocha River is a receptor to receive wastewater from household, hospital and industry, from where contaminants are transported in the river, affecting biodiversity and the ecosystem of the area. In this paper we estimated the maximum transport of total chromium and chloride anion by applying the analytical model of Ogata & Banks (1961), and the results obtained are grouped into three zones: Contaminated, transition, and uncontaminated. The analytical model was applied with 13 samples collected from the river piezometers installed near Rocha, where they are arranged in two lines, i.e. RH-1 to RH-6 as the first line and RH-9 to RH-12 as the second line. The total chromium concentrations range from 0.16 mg/L (RH-1) and 0.11 mg/L (RH-9) at the closest points to Rocha River, to 0.13 mg/L (RH-7) and 0.03 mg/L (RH-12) at the most remote points to the river. The advance of the pollutants does not exceed 50 meters with respect to the axis of the Rocha River.  相似文献   

PCR-DGGE解析阴离子交换膜生物反应器反硝化过程中微生物群落结构变化   总被引：3，自引：0，他引：3  

高孟春  梁方圆  杨丽娟  杨瑒  李冰  朱玉姣  顾雯  徐婕 《中国海洋大学学报(自然科学版)》2010,40(4)

通过扫描电镜和聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)方法考察了进水NO3-浓度变化对阴离子交换膜生物反应器微生物种群结构的影响。研究结果表明,在进水NO3-浓度从47.01 mg/L逐渐增加到168.55 mg/L的过程中,出水中NO3--N浓度满足我国饮用水水质标准中小于10 mg/L的要求。电镜扫描图显示微生物的形态结构发生了很大变化。对不同阶段的样品进行PCR-DGGE图谱和相似系数分析,发现随着反应的持续进行,微生物种群结构发生了演替变化,证实污泥微生物生态能够迅速进行优胜劣汰的筛选,调整内部微生物种群结构,从而达到适应环境的目的。  相似文献   

Isobar Attenuation Using Anion–Gas Reactions for Accelerator Mass Spectrometry and Application to 36Cl     

John Eliades  Xiaolei Zhao  William E. Kieser  Albert E. Litherland 《Geostandards and Geoanalytical Research》2010,34(2):107-115

Preliminary tests of a prototype radio-frequency quadrupole (RFQ) collision cell system, known as an isobar separator for anions (ISA), for the removal of isobaric interferences for accelerator mass spectrometry (AMS) and for studies of anion–gas interactions are reported. The ISA decelerated a mass-analysed beam of anions from an energy (∼ 20 keV) typically generated by an AMS ion source to < 10 eV. RFQs and electrostatic lenses then guided the ions through the collision cell where ion-gas collisions reduced both the energy and energy spread of the ion beam (cooled the ions) and ion-gas reactions attenuated most of the unwanted isobars. The anions were then re-accelerated to their original energy for injection into the rest of the AMS system. With the ISA installed on a full 3 MV AMS system, attenuations of ³²S^-, ¹²C₃^- and ³⁹K^- by six, seven and greater than ten orders of magnitude, respectively were achieved using 0.7–1 Pa NO₂ gas in the collision cell, while maintaining approximately 10–30% of the chlorine anion transmission. A further measurement of a ³⁶Cl/Cl = 4.1 × 10^-11 RM is also described. The results suggest that the ³⁶Cl/Cl lower detection limit of the current system was 10^-14–10^-15 for samples that could be prepared with S/Cl ratios below 10 μg g^-1.  相似文献   

2013 年春季华南师范大学石牌校区大气冷凝水的化学特征与来源     

温小浩  纪奕璇  吴杭  吴怡洁  周佳明 《热带地理》2016,36(4):642-648

通过人工制冷的方法收集2013 年华南师范大学石牌校区大气冷凝水52 个样品,对其进行pH 值和阴阳离子分析。结果表明：2013 年春季石牌校区绝大多数冷凝水样品的pH 值分布范围为5.00~6.47,平均值为5.97,已不属于酸雨。冷凝水的阴阳离子总质量浓度（TDS）介于57.87~484.38 μeq/L 之间,平均值为154.53 μeq/L;各离子质量浓度高低依次为2-4 SO ＞Ca2+＞ -3 NO ＞Na+＞Cl-＞NO2-＞Mg2+≈K+＞F-。石牌校区冷凝水的这种离子质量浓度分布特征显示：其清洁程度较优于2011 年春季该校区和同期上海大气冷凝水,而较差于云南丽江的大气降水,与广东鹤山和青海瓦里关山等地的大气降水相当。其污染来源除部分属自然源外,还主要与建筑活动、工业生产、汽车尾气等人类活动等有密切关系。  相似文献   

Comparison of Pb Purification by Anion-Exchange Resin Methods and Assessment of Long-Term Reproducibility of Th/U/Pb Ratio Measurements by Quadrupole ICP-MS     

Balz S. Kamber  Annette H. Gladu 《Geostandards and Geoanalytical Research》2009,33(2):169-181

A comparison between HBr-HCl and HBr-HNO₃ based anion chemistry is presented to test the efficiency of Pb purification in the preparation of samples for isotope ratio measurement by ICP-MS. It was found that the small advantages in yield and blank offered by the HNO₃-based method were more than compensated by the more effective matrix removal of the HCl-based method. Apart from very zinc rich matrices (e.g., sphalerite), a careful single pass purification using HBr and HCl removed more than 99.9% of the matrix. In preparation for the isotope ratio analysis, a small (2–5% m/v) liquid sample aliquot was analysed to determine U, Th and Pb concentrations by solution quadrupole ICP-MS. This allowed accurate prediction of the expected ion signal and permitted optimal spiking with Tl, if desired, for mass bias correction. Long-term results for international rock reference materials showed reproducibilities of better than 1% (Th/U) and 1.5% (U/Pb). For most geological applications, such analyses obviate the need for isotope dilution concentration measurements.  相似文献   

早更新世东山古湖氯离子含量变化与季风演化   总被引：15，自引：0，他引：15  

奚晓霞  黎德芬 《冰川冻土》1996,18(2):125-130

高分辨率东山古湖沉积物中氯离子含量变化表明，早更新世早期亚洲季风稳定建立，其变化较小。早期较干；中期出现大湿润期，氯离子含量最低；晚期（１．７－１．６６Ｍａ）再变干。  相似文献   

K2B4O7的Pitzer参数的计算          下载免费PDF全文

李丽娟  姚燕  宋彭生 《盐湖研究》2002,10(4):38-43

由于硼酸盐在电解质中的特殊性 ,硼酸盐的热力学问题一直被化学家所重视。根据文献数据 ,经多种处理获得K2 B4 O7不同存在形式的硼氧配阴离子的Pitzer纯盐参数、K2 B4 O5(OH) 4电离化学计量平衡常数Km。采用所获得的Pitzer纯盐参数计算K2 B4 O7不同存在形式的硼氧配阴离子的渗透系数 ,并与表观实验值进行比较  相似文献   

常见阴离子配位体对土壤吸附铜的干扰规律研究     

李绪谦  段长春 《吉林大学学报(地球科学版)》1992,(1)

土壤对重金属离子的吸附容量明显受阴离子配位体的影响。本文通过试验探讨了Cl~(-),SOi_4~(2-)HCO_3~(-)阴离子在不同的pH值条件下,分别对土壤吸附铜的干扰规律。运用反求吸附参数法评价了不同阴离子对铜吸附量的干扰程度,论证了土壤与地下水之间元素迁移的规律。  相似文献   

熔体阴离子结构团缔合过程中声子熵的研究     

何安明  李秉新  石焕文 《矿物岩石地球化学通报》1997,(2)

熔体阴离子结构团缔合过程中声子熵的研究何安明李秉新石焕文（西安地质学院，西安７１００５４）关键词熔体阴离子结构团缔合声子熵近年来，中外学者已经开始重视对岩浆熔体的物理过程和机制（如利用喇曼光谱直接测定硅酸盐熔浆的结构等）的研究工作，并取得了重要进展。...  相似文献