Neutrino detection with CLEAN

This article describes CLEAN, an approach to the detection of low-energy solar neutrinos and neutrinos released from supernovae. The CLEAN concept is based on the detection of elastic scattering events (neutrino–electron scattering and neutrino–nuclear scattering) in liquified noble gases such as liquid helium, liquid neon, and liquid xenon, all of which scintillate brightly in the ultraviolet. Key to the CLEAN technique is the use of a thin film of wavelength-shifting fluor to convert the ultraviolet scintillation light to the visible, thereby allowing detection by conventional photomultipliers.

Liquid neon is a particularly promising medium for CLEAN. Because liquid neon has a high scintillation yield, has no long-lived radioactive isotopes, and can be easily purified by use of cold traps, it is an ideal medium for the detection of rare nuclear events. In addition, neon is inexpensive, dense, and transparent to its own scintillation light, making it practical for use in a large self-shielding apparatus. The central region of a full-sized detector would be a stainless steel tank holding approximately 135 metric tons of liquid neon. Inside the tank and suspended in the liquid neon would be several thousand photomultipliers.

Monte Carlo simulations of gamma ray backgrounds have been performed assuming liquid neon as both shielding and detection medium. Gamma ray events occur with high probability in the outer parts of the detector. In contrast, neutrino scattering events occur uniformly throughout the detector. We discriminate background gamma ray events from events of interest based on a spatial maximum likelihood method estimate of event location. Background estimates for CLEAN are presented, as well as an evaluation of the sensitivity of the detector for p–p neutrinos. Given these simulations, the physics potential of the CLEAN approach is evaluated.     

Indirect estimation of the swelling percent and a new classification of soils depending on liquid limit and cation exchange capacity

This paper describes the dependence of the swell percent (%S) on the soil properties, namely, liquid limit (LL) and cation exchange capacity (CEC). This study provides the statistical model that can be used to obtain an indirect estimation of %S due to CEC and LL. According to the coefficient of correlation (R² = 0.91), VAF (91.5%) and RMSE (0.727) indices, multiple regression model has a high prediction performance. Although CEC values play an important role in the swelling behaviour of clayey soils, there is no universally accepted simple quantitative swelling potential classification at present. In this paper, a new swelling potential classification and graph, having four respective zones indicating the low, moderate, high, very high swelling potential, was also developed and proposed. This classification will serve to the engineers in order to evaluate the expansivity of the soils, in practice.     

头孢拉定、诺氟沙星及罗红霉素在中华鳖(Pelodiscus sinensis)日本品系体内残留代谢的比较研究

应用液相色谱-串联质谱技术比较研究了头孢拉定、诺氟沙星及罗红霉素3种渔药在中华鳖(Pelodiscus sinensis)日本品系体内的残留代谢规律。在(25.0±2)°C饲养条件下,通过连续7d对健康中华鳖日本品系投喂分别含有30mg/kg头孢拉定,300mg/kg诺氟沙星或30mg/kg罗红霉素的药饵后,比较分析了3种渔药在中华鳖日本品系体内各组织中的浓度变化。结果表明:头孢拉定和诺氟沙星的代谢符合一室消除模型,罗红霉素的代谢符合二室消除模型。头孢拉定在中华鳖日本品系血液、肌肉和肝脏中消除半衰期T1/2(Ke)分别为6.132h、9.002h和10.132h。诺氟沙星在中华鳖日本品系血液、肌肉和肝脏中消除半衰期T1/2(Ke)分别为22.526h、39.715h和41.585h。罗红霉素在中华鳖日本品系血液、肌肉和肝脏中消除半衰期T1/2(β)分别为38.54h、15.65h和100.5h。建议选用肝脏作为今后中华鳖质量安全残留监控靶组织。     

超高效液相色谱法直接快速测定环境水样中硝基苯和苯胺

建立了超高效液相色谱直接快速测定环境水样中硝基苯和苯胺的分析方法。取900μL水样与100μL乙腈混匀,用微孔滤膜(0.2μm,有机系)过滤。采用1.7μm小颗粒填料的BEH phenyl柱,以乙腈/醋酸铵溶液为流动相,硝基苯和苯胺分别用紫外和荧光检测器检测,分析时间仅1.1 min。硝基苯和苯胺的线性范围分别是0.485～4850μg/L和0.495～1978μg/L,方法检出限分别是0.194μg/L和0.099μg/L,相关系数均在0.995以上。硝基苯9.70μg/L、194μg/L、1940μg/L三个浓度水平回收率在98.3%～101%,相对标准偏差在1.11%～2.03%。苯胺9.89μg/L、198μg/L、1978μg/L三个浓度水平回收率在98.6%～104%,相对标准偏差在0.75%～5.85%。与传统液相分析方法相比,本方法线性范围更宽,灵敏度更高;直接进样简化了前处理环节,减少采样体积和有机试剂的使用;分析效率高,适用于地下水、地表水等多种水质样品中痕量到常量范围的硝基苯和苯胺快速测定。     

高效液相色谱法测定盐酸阿考替胺三水合物工业品含量

盐酸阿考替胺三水合物为第一个胃肠蠕动改善药物,用来治疗功能性消化不良,作为一种新药,其分析测定方面的报道甚少,已有的报道采用高效液相色谱(HPLC)以甲醇-磷酸二氢钾-辛烷磺酸钠为流动相进行测定,由于使用了离子对试剂辛烷磺酸钠,因而分析过程比较耗时且保留不够稳定。本文基于盐酸阿考替胺三水合物为两性化合物,建立了测定其含量的高效液相色谱分析方法。测定方法采用C18(4.6 mm×150 mm,5 μm)色谱柱,以甲醇-20 mmol/L乙酸铵水溶液=45:55(V/V)为流动相(pH 6.8)进行等度洗脱,紫外检测波长选择280 nm,盐酸阿考替胺三水合物的保留时间合适且峰形较好,出峰时间为8 min,总分析时间为23 min。在优化色谱条件下,盐酸阿考替胺三水合物的浓度在0.0006~1.0 mg/mL范围内线性关系良好,检出限为0.0002 mg/mL,日内、日间测定的相对标准偏差(RSD)均小于1.0%。该方法不添加离子对试剂,有利于色谱系统的快速平衡,提高了实验的重复性和可操作性,可对盐酸阿考替胺三水合物工业品进行快速分析,实现对原料药的质量控制。     

罗布泊第四纪湖泊沉积序列及钾盐资源的形成

为在我国新生代大陆沉积盆地开展区域找矿及钾盐资源预测提供科学依据, 采用地球卫星遥感资料和地面调查与化学测试以及区域盐湖卤水演化环境的演绎分析等手段, 综合方法, 揭示了罗布泊盆地第四纪沉积层序和湖泊气候环境变化的基本特征与古湖泊湖水及现代湖水的饱和流结晶路线及成盐成矿演化趋势.区域盐湖卤水演化环境和地质钻探资料及相图表明, 罗布泊地区钾盐矿床的成盐矿物以钾的硫酸盐矿物为主, 并没有出现真正意义上的钾盐沉积阶段(即氯化物钾盐析出阶段), 而钾盐卤水矿床却是一个积极的找矿方向.根据断裂组合及深部地质作用的分析, 这一地段是现代地质作用条件下形成的呈北东向展布的地堑构造系统, 富钾卤水蕴藏在地堑构造系统的中央断裂带内.综合分析表明, 通过地堑构造系统的中央断裂的贯通作用, 使深层卤水以及表层渗滤水向断裂破碎部位聚集, 并由于深部卤水的运动, 使深层盐岩系地层发生选择性溶解和表层渗滤水, 使浅部疏松堆积物的易溶性氧化钾溶解, 从而导致富钾卤水的富集而形成超大型液体钾盐矿床.     

基于BIF条带状铁建造矿化特征的国际铁矿石盈亏平衡运营成本定量研究

国内外铁矿石价格对标基准多采用离岸价或到岸价,而非盈亏平衡运营成本,难以揭示我国铁矿石所面对的真实市场承压价格。为了厘清国际一线生产商的铁矿石盈亏平衡运营成本价格,本文对世界上最重要的条带状铁建造(BIF)矿产地——西澳哈默斯利盆地高品位赤铁矿矿床的矿化特征及代表性铁矿石产品展开系统研究,同时引入巴西铁四角地区的铁英岩型赤铁矿矿石作为对照,分析全球典型高品位赤铁矿矿石经济指标。结合前人研究成果,将西澳哈默斯利盆地与BIF相关的高品位赤铁矿的富集矿化类型划分为假象赤铁矿-针铁矿、微板状赤铁矿与河道沉积型赤铁矿,巴西铁四角主要为铁英岩型赤铁矿。上述各矿化类型对应的铁矿石产品的铁元素含量均高于56%;在杂质元素含量上,假象赤铁矿-针铁矿的磷含量高,微板状赤铁矿的磷、硫含量较高,河道沉积型赤铁矿的磷、硫含量较低,铁英岩型赤铁矿含锰。经定量估算,西澳力拓、必和必拓、FMG和巴西淡水河谷的铁矿石盈亏平衡运营成本价格分别为34.66、36.76、47.35、38.07美元/干吨,可为中国海外权益铁矿项目开发提供运营成本的参考。     

Comparison of petrogenetic signatures between mantle-derived alkali silicate intrusives with and without associated carbonatite, Namibia

We compare the petrogenetic and chemical signatures of two alkali silicate suites from the Cretaceous Damaraland igneous province (Namibia), one with and one without associated carbonatite, in order to explore their differences in terms of magma source and evolution. The Etaneno complex occurs in close spatial proximity to the Kalkfeld bimodal carbonatite–alkali silicate complex, and is dominated by nepheline (ne)-monzosyenites and ne-bearing alkali feldspar syenites. The Etaneno samples have isotopic compositions of ⁸⁷Sr/⁸⁶Sr(i)=0.70462–0.70508 and Nd=−0.5 to −1.5, with the highest ⁸⁷Sr/⁸⁶Sr(i) and lowest Nd values observed in evolved samples. The magma differentiated via olivine, feldspar, clinopyroxene, and nepheline (ne) fractionation in a F-rich system, which fractionated Zr from Hf, and Y from Ho. Partly glassy, recrystallized inclusions in some samples are less evolved than their host rocks and contain a cumulate component (nepheline, plagioclase). The Kalkfeld ne-foidites (ijolites) and ne-syenites have ⁸⁷Sr/⁸⁶Sr(i)=0.70285–0.70592 and Nd=0.5 to 1.1. The isotope ratios show no consistent variation with rock composition, and they are in the same range as the associated carbonatites. The Kalkfeld silicate magma fractionated nepheline and alkali-feldspar in a CO₂-dominated, F- and Ca-poor system. As a result, the rocks display some major and trace element trends distinctly different from those of the Etaneno samples.

We suggest that the Etaneno and the Kalkfeld magmas represent different melt fractions of a heterogeneous mantle source, resulting in different compositions especially with respect to CO₂ contents of the primitive, parental magmas. In this scenario, the carbonated alkali silicate Kalkfeld parental melt contained a critical CO₂ concentration and underwent liquid separation of carbonate and silicate melt fractions at crustal depths. The resulting silicate melt fraction experienced a very different mode of differentiation than the carbonate-poor Etaneno parental magma. Thus, the Kalkfeld rocks are depleted in Ca and other divalent cations, as well as F, rare-earth elements (REE), Ba, and P relative to the Etaneno syenites. We interpret these differences to reflect the partitioning of these elements into the carbonate melt fraction during immiscible separation.     

地基微波辐射计的雨天探测

该文讨论了地基微波辐射计在雨天探测遇到的问题及可能的解决途径.介绍了对天线着水层做的仪器订正,给出了用一维雨天大气辐射传输模式模拟得到的反演水汽总量Q和云液水总量L的方法,并给出雨天观测资料的统计分析实例.结果表明,在雨强小于20mm/h范围内，都有可能由地基辐射计测值定量得到Q和L雨天探测遇到的技术问题正在逐步解决；目前我们已能在统计意义上测量天气过程的降水效率等参量。     

Testing the ability of bentonite-amended natural zeolite (clinoptinolite) to remove heavy metals from liquid waste

 The design of environmentally sound liquid waste containment structures has become a crucial task in engineering applications due to ever increasing groundwater contamination from such sites. Construction of such structures usually requires a bottom liner of low hydraulic conductivity as part of the design. In order to reduce the hazards associated with liquid wastes including landfill leachate, bentonite-amended natural zeolite is proposed as an alternative to conventional earthen liners. Among many contaminants associated with liquid wastes, heavy metals are the most dangerous ones. This paper deals with determining the ability of natural zeolite to remove heavy metals from aqueous waste. For this purpose, crushed natural zeolite (clinoptinolite) is amended with commercial powdered bentonite to yield a soil mixture low in permeability and high in ion-exchange capacity. Leachate from a conventional landfill is used as the percolation fluid. Concentrations of certain heavy metals in the effluent fluid percolated through the bentonite-zeolite mixture are compared with that of initial leachate. The conclusion is reached that certain metals are efficiently removed from the influent solution by the soil matrix whereas some ions do not show significant reduction in concentration. This is attributed to high hydraulic conductivity of the bentonite-zeolite mixture.