多层螺旋CT肝脏三期增强扫描质量评价的探讨

多层螺旋CT和高压注射器的应用，使全肝动态多期增强扫描成为可能，但具体应用中，要想获得满意的肝脏三期增强效果，技术因素和患者因素也不容忽视。本文从科室影像服务器中提取在线的肝脏三期增强影像资料26例进行主观评价和CT值测量分析，结果表明，所有病例影像显示均无不满意评价，其中门脉期和实质期显示满意率均为100％，但动脉期显示满意率为65．4％，由此看出肝脏三期增强扫描的技术难点在动脉扫描时机的把握上，能否正确设置造影剂注射后的扫描延迟时间至关重要，文中对能够影响扫描延迟时间的因素进行说明并提出相应操作对策。     

Effet du vieillissement des céramiques poreuses sur leur capacité à évaluer la concentration de pesticide en solution

The soil solution sampling by ceramic cups allows pesticide transfer monitoring in the soil during long times. The ageing of material involves a bias in the sampling results. In laboratory, the comparison of two types of ceramic suction cups, new and installed in situ during four years, shows a modification of the hydrodynamic properties and a possible evolution of the adsorption capacity of the matrix. The passage rate, as well qualitative as quantitative, is better for the old material. Recommendations about site management are finally exposed. To cite this article: N. Domange et al., C. R. Geoscience 336 (2004).     

Determination of nitrophenols,diaminotoluenes, and chloroaromatics in ammunition wastewater

Methods for the determination of three compound classes, i. e. diaminotoluenes, nitrophenols, and chloroaromatics in groundwater of a former ammunition plant are reported. Diaminotoluenes were extracted by discontinuous liquid/liquid-, nitrophenols by continuous liquid/liquid-extraction using dichloromethane, and chloroaromatics by solid-phase extraction. These compound classes may be analyzed by gas chromatography (GC) or gas chromatography coupled to mass spectrometry (GC/MS) without derivatization or after derivatization with N-methyl-bis(trifluoroacetamide) (MBTFA) or heptafluorobutyric anhydride (HFBA) in the case of diaminotoluenes and HFBA or acetic anhydride in the case of nitrophenols. An atomic emission detector (AED) coupled to a gas chromatograph may be employed for the analysis of chloroaromatics. High selectivity can be achieved using the characteristic wavelengths of chlorine. A variety of these compounds were identified and quantified in a groundwater sample from the former ammunition plant Elsnig (Saxony, Germany). Concentrations were in the lower ppb range. Thus, dichlorobenzenes which may have been used as substituents at the end of World War II could be identified in groundwater samples at this site.     

三杯风速传感器非水平风场测量性能

为解决三杯风速传感器在计量检定条件下与观测场景中环境差异所导致的测量数据误差,致力于研究空气流速计量标准在量值传递过程中的真实性、准确性和一致性,为新一代三杯风速传感器作为计量器具的新产品型式评价提供思路和参考指标,依据杯式测风仪测量方法与自动气象站风速风向传感器检定规程,并在实验中加入了主体由角度编码器构成的自动化转盘系统,设计了三杯风速传感器在非水平风场内测量性能水平实验。通过调整三杯风速传感器在风洞试验段内的倾斜角度,模拟其在自然界非水平风场中的测量状态,同步采集风洞的标准指示风速、三杯风速传感器的实测风速以及其相应的倾斜角度,计算示值误差,利用方差分析、趋势分析、相关性分析和线性回归分析等统计方法,对不同倾斜角度下三杯风速传感器示值误差进行研究,得出了三杯风速传感器在风洞试验段内的示值误差与实测风速和倾斜角度之间的相关关系,提出了三杯风速传感器在非水平风场下的测量性能指标。研究了三杯风速传感器在非水平风场中实测风速与标准风速和倾斜角度的回归关系,提出了三杯风速传感器在计量环境下非水平风场中数据的量值传递修正算法。     

VAMOS: A pathfinder for the HAWC gamma-ray observatory

VAMOS¹ was a prototype detector built in 2011 at an altitude of 4100 m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.     

Methods of metal release assessment in soil water at anoxic sites

Metal mobility at contaminated sites can be assessed by soil water investigations or by leaching tests. Leaching tests are usually carried out in open contact with the atmosphere disregarding possible changes of redox conditions. This can affect the original metal speciation and distribution, particularly when anoxic samples are investigated. In this study, the applicability of common leaching tests (the German S4 test (S4), ammonium nitrate extraction (AmmN), and saturation soil extraction (SSE)) is tested for the assessment of zinc release from sulfide‐bearing flotation residues of a former ore mine. Results are compared to soil solution samples obtained by centrifugation and suction cups. The influence of sample storage on S4 leaching test results is investigated in a long‐term study to assess oxidation kinetics. Within the first 200 days the release of zinc increases with a slope of 0.1 mmol kg^–1 d^–1 or 6.0 mg kg^–1 d^–1, respectively. Since oxidation of the sulfide‐bearing samples leads to a significant overestimation of metal release, a feasible modification for the conduction of leaching tests for anoxic material is proposed where oxidation is prevented efficiently. The modified SSE is found to be the only of the tested leaching procedures, which can be recommended for the assessment of current soil water concentrations at anoxic sites if direct investigation of the soil water is impossible due to technical reasons.     

桂西北喀斯特山区人口分布特征及其与自然因素的关系

选择第六次全国人口普查的最小行政单位——乡（镇）为基本单元,利用Lorenz曲线和空间相关分析方法分析桂西北喀斯特山区乡（镇）级尺度下的人口空间分布特征,运用地理探测器方法探测自然因素单独和叠加作用后对区域人口空间分布的影响强度。结果表明： 乡（镇）级研究尺度下的人口空间分布具有不均衡性特征,呈现一般显著正相关和一定的聚集性; 各自然因素空间分布对人口分布的影响呈现显著差异,研究区西北和中南部没有喀斯特分布的乡镇,人口密度随有利于人类居住因素的增加而增加,但平均人口密度仅79人/km ²。东部和南部有喀斯特分布的乡镇,人口密度与自然因素空间分布并非简单的增减关系,其随喀斯特分布面积的变化呈现起伏波动。 地理探测器的因子探测结果显示对人口空间分布的影响强度最大的为海拔高度,交互探测结果显示,任意两个自然因素叠加交互作用后的影响强度呈现非线性增强和双因子增强。可见,桂西北喀斯特山区与其他地区类似,海拔高度是影响人口空间分布的最主要因素之一,但喀斯特山区的河网密度及特有的地质地貌等因素对其人口的空间分布具有较强的催化作用,与其他因素叠加交互作用可进一步加强对人口分布的影响。     

Instrumentation plans for 1024×1024 HgCdTe detector arrays at the University of Hawaii

The U.S. Air Force Phillips Laboratory will build the 3.63 m Advanced Electro Optical System (AEOS) telescope on Haleakala, Maui. The Institute for Astronomy will participate in this project and will develop astronomical instruments optimized for using the AEOS telescope in survey projects. As part of this instrument development program 1024×1024 HgCdTe near-infrared detector arrays will be developed at the Rockwell International Science Center.     

The design and performance of IceCube DeepCore

The IceCube neutrino observatory in operation at the South Pole, Antarctica, comprises three distinct components: a large buried array for ultrahigh energy neutrino detection, a surface air shower array, and a new buried component called DeepCore. DeepCore was designed to lower the IceCube neutrino energy threshold by over an order of magnitude, to energies as low as about 10 GeV. DeepCore is situated primarily 2100 m below the surface of the icecap at the South Pole, at the bottom center of the existing IceCube array, and began taking physics data in May 2010. Its location takes advantage of the exceptionally clear ice at those depths and allows it to use the surrounding IceCube detector as a highly efficient active veto against the principal background of downward-going muons produced in cosmic-ray air showers. DeepCore has a module density roughly five times higher than that of the standard IceCube array, and uses photomultiplier tubes with a new photocathode featuring a quantum efficiency about 35% higher than standard IceCube PMTs. Taken together, these features of DeepCore will increase IceCube’s sensitivity to neutrinos from WIMP dark matter annihilations, atmospheric neutrino oscillations, galactic supernova neutrinos, and point sources of neutrinos in the northern and southern skies. In this paper we describe the design and initial performance of DeepCore.     

塔里木盆地轮南奥陶系风化壳SYT法物性探测试验研究

ＳＹＴ型物性探测仪自从１９９２年石油系统使用之后,先后在陕北,华北,吉林,大庆油田取得了一定的试验效果,在仪器硬件和方法软件不断改进的基础上,在塔里木盆地轮南地区又进行了深为５７００余米的探测试验,其界面探测精度误差为０．５％～１．２％,在地面上直接解译奥灰顶界面深度,奥灰风化壳裂隙性岩溶发育程度,判译地下油气有等方面,无疑这将会大大降低对油气勘探投资的风险系数,塔里木盆地轮南奥灰风化壳ＳＹＴ法试