Quantitative SIMS analysis of trace Au in pyrite using the infinite velocity (IV) method

The quantitative analysis of trace concentrations of Au in pyrite using a new procedure of SIMS quantification is investigated. Analysis of an Au implanted pyrite standard demonstrates the infinite velocity (IV) method as a viable procedure for evaluation of trace concentrations of Au in pyrite. Comparison of naturally occurring trace concentrations of Au in pyrite using standard-derived relative sensitivity factor (RSF) and IV quantification methods is shown as a means of evaluating the chemical environments in which Au is found in pyrite.     

藏南羊卓雍错流域水化学主离子特征及其控制因素

水化学主离子特征是流域湖泊的一个重要特征,对气候以及河流所经地区的环境具有指示作用.本文对藏南羊卓雍错流域水化学主离子组成特征及其控制因素进行分析,结果显示流域内不同水体(湖水、河水、地下水)之间的主离子组成以及水化学类型差异显著.其中,羊卓雍错的水化学类型为SO24--HCO3--Mg2+-Na+,巴纠错为SO24--Mg2+-Na+,沉错为SO24--Na+-Mg2+-Ca2+,普莫雍错为HCO3--SO24--Mg2+-Ca2+,空姆错为HCO3--SO24--Ca2+;流域河水中主要阴离子为HCO3-和SO24-,Ca2+为绝对优势阳离子;流域地下水化学类型则为HCO3--Ca2+.究其原因,流域水体化学组成主要受岩石风化作用控制;除此,羊卓雍错、巴纠错和沉错水化学组成亦受自身蒸发-结晶作用的影响.就入湖河水而言,羊卓雍错入湖河水整体受碳酸盐岩石风化的影响较大,蒸发岩溶解的影响次之;沉错和空姆错入湖河流(卡鲁雄曲)的蒸发岩来源则略大于碳酸盐岩来源;而硅酸盐对流域内河水的水化学性质影响较小.与入湖河水相比,羊卓雍错和沉错湖水的Mg2+、Na+和SO24-含量较高,而Ca2+和HCO3-含量较低.这应该与湖水蒸发强烈使得湖水中Ca2+和HCO3-析出并沉积到湖底有关.而空姆错由于湖泊面积小、入湖河水流量大,致使其湖水与入湖河水的主离子组成差异不显著.     

Fast generation of cluster states in a linear ion trap

We propose a practical scheme to generate cluster states by simultaneously accomplishing two-qubit conditional gating on an array of equidistant ions by using transverse modes. Our operation is robust to heating and insensitive to Lamb--Dicke parameter. Meanwhile, as it is carried out in a geometric quantum computing fashion, our scheme enables the fast and high-fidelity generation of cluster states. The experimental feasibility is discussed with sophisticated ion trap techniques.     

黄河三角洲平原型水库总磷的变动趋势

通过连续 4年对黄河三角洲 6座水库水环境化学的观测发现 ,水层中总磷 (TP)丰度存在明显的季节波动 ,并与氢离子 (H)或 (和 )氯化物 (Cl)丰度存在显著相关关系 (p<0 .0 1 ,p<0 .0 5) ,但没有发现其随着年度推移的变化规律。根据对 7座 9～ 2 6年不同库龄水库的调查发现 ,随着库龄的增加 ,底泥中沉积的总磷 (DP)显著增加 (p<0 .0 5)     

锂同位素在环境地球化学研究中的新进展

锂的两个稳定同位素(6Li和7Li)相对质量差较大,因此易产生明显的同位素分馏。业已查明,自然界中δ7Li值的变化在-40‰和 50‰之间。其中较小的δ7Li值见于海相生物碳酸盐样品,较大的δ7Li值见于某些盐湖卤水以及有孔虫的样品。由于明显的同位素分馏和不同地质体中截然不同的δ7Li值,锂同位素应用十分广泛,且在壳-幔演化、陆壳风化、卤水和污染水体示踪等研究领域取得显著成效。     

Geothermal-type Lithium Resources in Southern Xizang, China

High-temperature geothermal water has abundant lithium (Li) resources, and research on the development and utilization of geothermal-type lithium resources around the world are increasing. The Qinghai–Tibetan Plateau contains huge geothermal resources; especially, Li-rich geothermal resources in southern Xizang, southwestern China, are widely developed. The Li-rich geothermal spots in Xizang are mainly distributed on both sides and to the south of the Yarlung Zangbo suture zone. Such resources are often found in the intensely active high-temperature Li-rich geothermal fields and, compared with other Li-rich geothermal fields around the world, the Li-rich geothermal fluid in the Xizang Plateau, southern Xizang is characterized by good quality: the highest reported Li concentration is up to 239 mg/L; the Mg/Li ratio is extremely low and ranges from 0.03 to 1.48 for most of the Li-rich geothermal fluid; the Li/TDS value is relatively high and ranges from 0.25–1.14% compared to Zhabuye Li-rich salt lake (0.19%) and Salar de Uyuni (Bolivia) (0.08–0.31%). Continuous discharge has been stable for at least several decades, and some of them reach industrial grades of salt lake brine (32.74 mg/L). In addition, elements such as boron (B), caesium (Cs), and rubidium (Rb) are rich and can be comprehensively utilized. Based on still-incomplete statistics, there are at least 16 large-scale Li-rich hot springs with lithium concentration of 20 mg/L or more. The total discharge of lithium metal is about 4300 tons per year, equivalent to 25,686 tons of lithium carbonate. Drilling data has shown that the depth is promising and there is a lack of volcanism (non-volcanic geothermal system). With a background of the partial-melting lower crust caused by the collision of the Indo-Asia continent and based on a comprehensive analysis of the tectonic background of southern Xizang and previous geological, geophysical, and geothermal research, deep molten magma seems to provide a stable heat source for the high-temperature Li-rich geothermal field. The Li-rich parent geothermal fluid rushes to the surface to form hot springs along the extensively developed tectonic fault zones in southern Xizang; some of the Li-rich fluid flows in to form Li-rich salt lakes. However, most of the Li-rich geothermal fluid is remitted to seasonal rivers and has not been effectively exploited, resulting in great waste. With the continuous advance of lithium extraction technologies in Li-rich geothermal fluid, the lithium resource in geothermal water is promising as a new geothermal type of mineral deposit, which can be effectively exploited. This is the first study to undertake a longitudinal analysis on the characteristics, distribution and scale, origin and utilization prospects of Li-rich geothermal resources in southern Xizang, research that will contribute to a deeper understanding of Li-rich geothermal resources in the area and attract attention to these resources in China.     

自动气象站防雷电源切换器的设计开发

自动气象站设备经常被从交流电源线路感应进来的雷击而造成损坏,目前安装的各种防避雷器还不能完全有效防止该现象的发生。如果能用两组蓄电池,交替给设备供电,就能将交流电源与设备隔离,起到防止电源线感应来的雷电击毁设备的事故。设计开发的防雷电源切换器通过检测蓄电池的供电电压,控制两微型电机的正反转,再经电机的传动装置,带动接点移动,达到两组蓄电池交替供电和充电。调整电机的走动行程,可使充电器与设备的间距达到8~10 cm,起到了电源防雷的目的。     

东亚地区降水离子成分时空分布及其特征分析

利用东亚酸沉降监测网(EANET)观测资料,对2001年东亚地区降水成分的时空分布特征进行了分析,通过与过去的观测进行对比,揭示东亚各地酸雨分布情况及降水化学特性差异,为东亚酸沉降长距离输送模式比较计划提供前期分析资料.分析结果表明:(1)东亚地区降水化学成分表现出明显的地域特征,滨海地区的日本降水含量中Na+、Cl-分别为219、208μmol·L-1居东亚地区之首,而中国西北地区Ca2+、NO-3、NH4+、SO24-、Mg2+、K+含量最高各为755、168、260、768、59.3、53.6 μmol·L-1;降水酸度主要受阳离子Ca2+、NH4+和阴离子SO24-、NO3-的影响.(2)东亚地区降水化学成分季节变化明显,除部分源自人为或工业排放源影响外(如北部地区冬季取暖),东亚地区气候呈季节变化也是影响的主要因子之一.春季沙尘源区沙尘、扬沙频繁,其上空存在较强的西风带,在天气系统冷锋影响下,沙尘粒子易随大风扬起而由锋前强烈抬升气流输送到对流层中层,在高空西风急流作用下输送到下游地区.(3)东亚地区酸雨区降水与以往主要以硫酸型酸雨为主的降水性质不同,除中国西南工业欠发达地区仍为硫酸型外,其他酸雨区均为硫酸和硝酸混合型.表征酸雨类型的特征参量[SO24-]/[NO3-]的比值在中国西南地区为3～5,东南和华南地区为0.5～3;其他各国均在0.5～3之间.