Long-term measurements of the concentrations of halocarbons in an urban area of Kraków, Poland

The results of the measurements of the concentrations of freons (F-11 and F-113), chloroform (CHCl₃), trichloroethane (CH₃CCl₃) and carbon tetrachloride (CCl₄) in air are presented. The data concern concentration measurements that have been conducted in Krakow since half way through 1997 to the end of 1999. The mean monthly values of these concentrations have been compared with the data from Mace Head, the station situated at a similar longitude as Krakow. It has been concluded that, in the observed period of time, the concentrations of the pollutants in Krakow are higher than in Mace Head. The mean monthly concentrations of F-11 and CCl₄ decrease in Krakow faster than in Mace Head (2.5 and 3.3 times, respectively). The concentrations of CHCl₃ and CH₃CCl₃ decrease at both locations, but the change is greater in Krakow. In Krakow, the observed increase of F-113 is 0.13 ppt/month and has an opposite trend than in the same period at Mace Head.     

塔里木盆地塔中沙漠区高分辨率地震勘探效果

塔中沙漠区地表被北东—南西向条带状沙层所覆盖,地形起伏剧烈,松散沙层厚度变化巨大,给地震资料采集、处理、解释带来了很大的困难。通过联合攻关,从地震波激发能量下传和反射波接收的研究入手,实现了全部潜水面以下激发,因地制宜、避高就低埋置检波器优化观测系统;针对该区石炭系和志留系低幅度构造、薄储层圈闭难以落实,奥陶系内幕地震资料反射波能量弱、信噪比低、叠加成像困难等问题,开展了沙丘对地震波吸收衰减分析和补偿技术、地表一致性处理技术、多域迭代静校正技术、精细速度场模型确立和偏移成像等配套技术的研究开发与应用。从而极大地改善了塔中沙漠区地震资料的品质,使中深层的石炭系、志留系、奥陶系对应的地震剖面主频从18～20Hz提高到36～40Hz;形成了塔中沙漠区油气勘探技术系列,精细刻画了塔中Ⅰ号带,锁定了油气勘探目标,推动了台盆区油气勘探再掀新高潮。     

The amylose and lipid contents,dimensions, and gelatinisation characteristics of some wheat starches and their A- and B-granule fractions

Starches isolated from 23 bread wheats (Triticum aestivum) and 26 durum wheats (T. durum) contained 26.3-30.6% (mean 29.1%) total amylose, 19.3–25.1% (mean 22.9%) apparent amylose and 783–1144mg 100g^?1 (mean 977 mg 100g^?1) lysophos-pholipids. Gelatinisation temperatures were 57.3–64.9°C (mean 61.8°C) and enthalpies 6.4–11.8 Jg^?1 (mean 9.7Jg^?1) in excess water, measured by differential scanning calorimetry. There were no correlations between any of these parameters. Starch granule size distributions were determined with a Coulter Counter and 100–channel analyser. A-granule mean volumes were 1235–2585μm³ (av. 1778), modal volumes 863–1804μm³ (av. 1264), mean diameters 13.9–16.0μm (av. 13.99), and specific surface areas 0.236–0.302m²g^?1. B-granule mean volumes were 35.4–100.4μm³ (av. 55.9), modal volumes 16.5–54.5μm³ (av. 27.7), mean diameters 3.66–5.07μm (av. 4.09), and specific surface areas 0.684–0.920m²g^?1. The B-granule contents of the starches were 12.8–34.6% (av. 27.3) by weight (sedimentation method) and 13.0–37.3% (av. 24.0) by volume (Coulter method), the latter being the more accurate method.     

鄂尔多斯西缘前陆盆地巨厚黄土地区地震采集技术

鄂尔多斯西缘前陆盆地表层地质地貌极其复杂，有巨厚黄土区、黄土-沙漠区及山前砾石-黄土区，独特的黄土地貌使得地震采集面临着诸多技术难题。根据以往巨厚黄土地区地震采集经验，采用多种方法系统地开展黄土表层结构精细调查，深入研究黄土地球物理特征及激发因素与表层黄土结构之间的关系，优选激发井位和井深，确保了激发效果；采用小道距、三线小线距、高密度空间采样技术，获得了高信噪比、高分辨率地震资料。研究表明，巨厚黄土地区地震采集时应优选激发井位和岩性，合理选择激发井深；坚持多深井组合激发、单井药量不宜过大总药量要大两项基本原则；采用高密度采样技术，提高采集资料的覆盖次数和信噪比。图10表1参15     

小型办公网络组网

通过实例,对小型办公网络组网中涉及到的需求设计、网络连接、网络设备、设备连接等进行了论述。     

充分灌与调亏灌溉条件下桃树滴灌的耗水量研究

本文研究了充分灌与调亏灌溉条件下桃树滴灌的耗水量。在田间设置有两个处理，其一是在整个生育期以蒸发量的80%进行充分灌溉；其二是在果实生长缓慢期以蒸发量的20%进行亏缺灌溉，而在其它季节以蒸发量的80%进行充分灌溉。利用石膏块土壤水分传感器和中子仪分别测量了根区土壤水势和土壤含水量的变化，并实测了果实生长量、枝条生长量和产量。利用水量平衡法得出了在上述两种滴灌条件下桃树不同生育期的日均耗水量与蒸发皿系数。与充分灌比较，调亏灌溉对产量没有影响，灌水量减少了32%，并有效抑制了枝条生长。     

机电排灌工程管理之我见

机电排灌工程是丘陵、滨湖地区的主要灌溉设施，必须建立适应市场经济的管理新机制，确保工程良性运行和巩固发展，满足不断发展的工农业生产需要。     

Design Methodology of the Structure of Postal Express Mail Networks of Aviation Channels in China

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MODELING LIQUID MASS TRANSFER IN HIGEE SEPARATION PROCESS

Correspondence concerning this paper should be addressed to Professor Richard S.H. Mah. Hsien-Hsin Tung is now affiliated with Department of Chemical Engineering, California Institute of Technology

Penetration theory is used to describe the liquid mass transfer in Higee separation process. Within a possible range of effective areas, it is shown that the predicted mass transfer coefficients are in reasonable agreement with the estimated mass transfer coefficients. The estimated coefficients were calculated from the experimental data and the possible effective areas. Hence it is concluded the penetration theory is generally applicable to describe liquid mass transfer in Higee separation process. The comparison also suggests that liquid mixing at the junctions of packing materials may be more complete in Higee process than in traditional process.     

广播电视农村覆盖现状浅析

加强农村广播电视的发展,提高其覆盖率是关键,针对这一问题,阐述了解决农村广播电视覆盖的手段,对农村广播电视覆盖现状做了详细的分析,并提出建议和措施。