Festkontaktierte potentiometrische Elektroden für Sulfatbestimmungen in wässrigen Lösungen     

Monika Berthold  Heimo Jahn  Heiner Kaden 《洁净——土壤、空气、水》2001,29(4):219-226

Solid‐contacted Potentiometric Electrodes for Measurements of Sulfate Ions in Aqueous Solutions A solid‐contact electrode for potentiometric measurement of sulfate ions in aqueous solutions was developed and examined. The electrode is based on a PVC membrane which contains the ionophore 3‐decyl‐1,5,8‐triazacyclodecan‐2,4‐dione (DTADD). Instead of the usual inner fluid junction, a polypyrrole layer applied on the inner side of the PVC membrane was employed as inner solid contact. The performance of this electrode was compared to solid‐state sulfate‐selective electrodes with the ionophore α,α′‐bis(N′‐phenylthioureylene)‐m‐xylene (BTH) and to electrodes in the coated‐wire configuration. For the parameters sensitivity, selectivity, and long‐term stability, electrodes with the DTADD ionophore show improved properties. In the sulfate concentration range of 5·10^–5...10^–2 mol L^–1 the slope of the response is –(26.8 ± 0.5) mV/decade. The new solid contact sulfate electrodes showed a very low drift of the electrode potential within a period of 150 days when the electrode was stored in 10^–2 M Na₂SO₄. In Na2SO4 solutions of the pH range of 4...9 the electrode potentials were constant. The 95% response time was about 10 s when the sulfate concentration was changed from 10^–4 mol L^–1 to 10^–3 mol L^–1. The selectivity with DTADD ionophore relating to the nitrate ions is higher than the selectivity with BTH. Improvements are also made in comparison with sulfate‐selective electrodes described in the literature which contain other ionophores with fluid inner reference electrolytes.  相似文献   

长输埋地管道振动台试验传感器布置方案研究     

韩俊艳  万宁潭  李立云  侯本伟  赵密  杜修力 《震灾防御技术》2018,13(1):13-22

在进行长输埋地管道振动台试验的过程中,针对数据信息的采集量测以及传感器的布置位置进行了研究。采用三维数值模拟的方法对管-土相互作用体系进行了地震反应分析,内容包括埋地管道结构纵、横向在非一致地震动作用下的地震响应及受力变形特征。根据计算结果确定了主观测断面及辅助观测断面的位置及观测断面上传感器布置的位置,在满足基本信息采集要求的前提下,对可供采用的信息采集通道进行了优化分配,由此确定本次试验的观测断面以及传感器的具体测量部位与数目。成果对试验获得成功起到了保障作用,可为同类试验提供参考。  相似文献   

山东莱州西岭勘查区ZK88-19深孔同径造斜绕障工艺          下载免费PDF全文

王林钢  潘垚  所建成  白露明  李召胜 《探矿工程》2020,47(12):55-59

山东莱州西岭勘查区ZK88-19号钻孔设计孔深2500 m,2016年12月开孔,于孔深2034 m处发生烧钻事故,处理孔底钻具时再次发生烧钻事故,导致2套钻具及2套内管总成滞留孔底;2017年8月,受划定环境保护区的影响,中断施工,直至2020年3月恢复施工,继续处理孔内事故难度很大;经过多次论证,应用了深孔同径造斜绕障技术,包括设计了造斜偏心楔、造斜钻头以及研发了偏心楔固定技术等,成功绕过事故段,恢复钻进。  相似文献   

GROUP HOME LOCATION AND HOST NEIGHBORHOOD ATTRIBUTES: AN ECOLOGICAL ANALYSIS     

G. Brent Hall  Alun E. Joseph 《The Professional geographer》1988,40(3):297-306

This paper investigates the characteristics of areas with numerous group homes (residential care facilities) that cater to a variety of user groups. An overview of patterns of locational concentration precedes the results of an ecological analysis for the Minor Planning Districts of the City of Toronto. The pattern of ecological correlates among the three group home types analyzed supports results obtained elsewhere, but cautions against inferring ecological associations identified for one sort of facility to other facility types, The conclusion questions the suitability of present areas of locational concentration of group homes as host environments.  相似文献   

RETRIEVING OVER-OCEAN PRECIPITABLE WATER FROM THE SSM/I MEASUREMENTS WITH SEVERAL REGRESSION ALGORITHMS^*          下载免费PDF全文

Chen Hongbin  Sun Haibing  Wang Pucai  Lu Daren 《Acta Meteorologica Sinica》1998,12(4):443-449

A collocated SSM/I and radiosonde measurement data set provided by the NASDA(Japan) was used to retrieve the total precipitable water(PW) over oceans.The retrieval results obtained with several regression algorithms were compared against the radiosonde measurements.It is shown that:(a) the routinely operational algorithm of Alishouse et al.(1990) yields significant underestimation in high PW regime and overestimation in low PW regime;(b) a cubic correction by Colton and Poe(1994) is not sufficient and globally improves slightly the retrieval results;and(c) the regression algorithm with the form of brightness temperature(T_b) function In(280-T_b) gives a little largely scattered retrievals in whole PW range but without considerable over-and underestimates in low and high PW regimes.To improve the estimation of the oceanic precipitable water from the SSM/I measurements,a composite algorithm with different forms of T_b function in low.medium and high PW regimes is proposed and tested.  相似文献   

An analysis of the Hubble Space Telescope Fine Guidance Sensor Coarse Track mode     

L. G. Taff 《Experimental Astronomy》1990,1(4):237-266

There are two guiding modes of the Hubble Space Telescope used for the acquisition of astronomical data by one of its six scientific instruments. The nominally more precise one is called Fine Lock and the other is known as Coarse Track. Two of the three Fine Guidance Sensors are locked onto Guide Stars, in one of these two modes, thus maintaining the spacecraft's line of sight to a few milli-arc seconds (nominally 7 milli-arc seconds for Fine Lock and 17 milli-arc seconds for Coarse Track). In this paper I report on the most realistic and extensive simulations to date of the Coarse Track guidance mode. These simulations clearly show that the precision of Coarse Track is influenced by one adjustable parameter and that for default operating conditions its precision is 12 milli-arc seconds. A factor of two improvement should be possible by modifying the key parameter which governs the precision of Coarse Track. The importance of this for the scientific mission on the Hubble Space Telescope is that the use of Coarse Track in place of Fine Lock will result in a 1/3 reduction of engineering overhead per scientific target acquisition.See text for a full explanation.  相似文献   

GPS／INS直接定向精度分析   总被引：1，自引：0，他引：1  

白志刚  鲁建伟 《全球定位系统》2009,34(2):27-30

近年来，GPS／INS融合技术在国内逐渐被应用于航空摄影测量中，利用其直接获得外方位元素，从而减少外业控制点。通过试验，在DMC数码相机同高精度的GPS／INS系统联结下，直接获取了试验区的外方位元素，并对GPS／INS数据直接定向的精度进行分析和总结，得出了一些有益的结论。  相似文献   

电子地图的自适应注记研究与实现   总被引：1，自引：0，他引：1  

陈长林  魏海平  陈换新  李玉 《测绘科学》2009,34(5)

地图注记的自动配置是地图制图与GIS的难点之一,传统的注记自动配置,采用的算法过于复杂,难以满足电子地图实时响应的要求;而且传统地图采用的是静态注记,而电子地图的屏幕范围有限,往往导致地图视口边界的注记不完整。本文提出一种网格标记法实现注记压盖的快速检测,并基于此方法实现注记配置的压盖避让和动态调整,即注记的自适应配置。实践表明,此方法能有效改善电子地图的显示效果和运行效率,具有较高的实用性。  相似文献   

无线传感器网络中基于能量平衡的部署算法     

任丽婕  郭忠文  唐瑞春 《中国海洋大学学报(自然科学版)》2008,38(5)

为平衡能量损耗并用网络生存期最大化,提出1种无线传感器网络(WSNs)中基于能量平衡的节点部署算法.此算法基于距离调整网络部署,也就是根据不同位置的节点能耗调整节点的间距.文中提出能耗最低点并不等于生存期最优.仿真证明基于这种部署策略网络的能耗大大降低,网络生存期比均匀部署策略高160%,同时给出调整距离、网络半径、节点传递范围和节点数量之间的参考关系.  相似文献   

智能化地图注记   总被引：1，自引：0，他引：1  

罗广祥  马智民  刘元会  田永瑞  李芹芳 《地球科学与环境学报》1999,21(3)

详细讨论了候选注记位置的确定、候选注记位置的质量评定以及最佳注记位置的选择方法。在全面考虑注记配置顾及因素的基础上， 对注记位置的质量进行了量化评定， 提出候选注记位压盖要素情况质量评定函数、位置优先性评定函数、位置松驰度评定函数， 从而使对注记位置质量好坏的评价有一个统一的、合理的量化标准， 这对优化注记配置， 减少智能注记过程中超常规配置出现的数量具有重要意义。在选择最佳注记位置策略方面， 提出逐次选取的方法， 使智能注记软件能灵活适应不同复杂程度的地图， 减少计算及判断工作量， 提高工作效率， 快速达到最佳的注记配置效果。  相似文献