高等级公路测量基准面的确定及长度变形分析

分析了高等级公路平面控制网导线边投影长度变形与测区平均高程及投影带宽度的关系．根据长度变形是否满足国家标准GB50026－93要求（≤2．5cm／1km）而确定坐标系统．给出了不同坐标系统之间的换算关系．文中算例表明：用简单算法能达到公路工程测量的精度要求．     

ASP.net中的SQL查询技巧及应用

ASP.net是微软公司推出的新一代网站程序开发框架,是.net框架提供的一个统一的Web开发模型。利用ASP.net技术可以方便开发动态网站,而在网站开发中数据查询占据很大的比例。     

Development of buffer methods and evaluation of pedotransfer functions to estimate pH buffer capacity of highly weathered soils

The pH buffer capacity of a soil (pHBC) determines the amount of lime required to raise the pH of the soil layer from its initial acid condition to an optimal pH for plant growth and the time available under current net acid addition rate (NAAR) until the soil layer acidifies to a critical pH leading to likely production losses. Accurate values of pHBC can also be used to calculate NAAR from observed changes in soil pH. In spite of its importance, there is a critical shortage of pHBC data, likely due to the long period of time needed for its direct measurement. This work aimed to develop quick, simple and reliable methods of pHBC measurement and to test these methods against a slow (7‐day) titration used as benchmark. The method developed here calculates pHBC directly from the pH buffer capacity of the buffer solution and the increase in soil pH and corresponding decrease in pH of the buffer solution following mixing and equilibration. The pHBC values calculated using Adams and Evans or modified Woodruff buffers were in accord with those measured by slow titration. Buffer methods are easily deployed in commercial and research laboratories as well as in the field. The advantage of using buffer solutions to calculate pHBC instead of lime requirement is the broad application of this soil property. The pHBC of a soil is an intrinsic property that would not be expected to need remeasurement over periods of less than decades. Recurring lime requirement can be calculated from the soil's pHBC, initial and target pH values. A large proportion of the variability in pHBC was explained by the soil organic carbon content. This relationship between pHBC and soil organic carbon content allowed us to develop local pedotransfer functions to estimate pHBC for different regions of Australia.     

闽南海区休渔前后张网作业渔获物组成比较分析

本文主要根据2008年闽南海区张网作业渔业资源监测资料，对休渔前后（4月和8月）张网作业渔获物组成进行比较分析。结果表明：2008年休渔前后都以捕经济种类幼鱼为主。4月带鱼、二长棘鲷、刺鲳、鲐鱼、中华管鞭虾等主要经济种类渔获重量占总渔获物重量69．6％，其中带鱼幼鱼数量最多，占总渔获数量的26．2％（每网渔获尾数744ind），居第一位；且个体极小，基本上全为幼鱼，平均体重8．1g。8月带鱼、二长棘鲷、短尾大眼鲷、叫姑鱼、白姑鱼、须赤虾等主要经济种类渔获重量占总渔获物重量50．9％。带鱼数量明显减少（每网渔获尾数226ind），但个体增大，肛长140mm以上占63．6％，平均体重54．5g，比4月增加46．4g。并结合2004、2007年有关资料，较为详细说明休渔前（4月）张网作业对近岸经济幼鱼、幼体损害比休渔结束后（8月）严重，通过休渔对带鱼等经济种类幼鱼资源起了一定保护作用。     

Analysis of mesh breaking loads in cotton gill nets: Possible solution to ghost fishing

ABSTRACT:   A small number of fishers in Chiba Prefecture of eastern Japan use cotton gill nets to catch Japanese spiny lobster Panulirus japonicus. To examine the advantages of cotton gill nets, we analyzed changes in mesh breaking load of a new cotton gill net used in a fishing operation. A new cotton gill net was also soaked in a seawater tank to simulate ghost fishing conditions. The average mesh breaking load of new cotton mesh was 50.3 N. This value decreased to 19.0 N after 38 days (∼912 h), and after 82 days (∼1968 h) the mesh could be easily torn (breaking load 0.07 N). Under fishing conditions, the cumulative soak time was only 744.4 h over 19 months. The average breaking load at the end of this period was 43.1 N, a strength 86% that of the presoaked mesh. The mesh breaking load of a cotton gill net continuously soaked for 744.4 h was 26.1 N, as estimated from tank experiment data. Thus, a cotton gill net maintains reasonable strength under typical use conditions, but will degrade if lost at sea.     

微电脑在二片式对拖网设计上的应用及捕捞效果分析

本文分析了二片式对拖网设计软件设计的基本原理及渔获效果的对比。结果表明,本软件设计先进、科学,具有良好的适用性、精确性、高度灵活性和快速简便性等优点;利用本软件设计的网具,具有良好的渔获效果。     

校园网ARP病毒的应对与防范

如何防范与应对ARP病毒现已成为摆在各校园网网络管理者面前的一个厄待解决的技术难题。本文阐述了ARP协议工作的原理，分析了ARP病毒攻击过程，剖析了ARP病毒对网络的危害，并结合校园网络的架构特点给出了ARP病毒防范与应对的方法。     

一种MELSEC—NOVELL网关的设计与实现

在分析了ＮＯＶＥＬＬ网和ＭＥＬＳＥＣ网的基础，提出一种ＭＥＬＳＥＣ－ＮＯＶＥＬＬ网关的硬件设计实现方法。     

集中供热热网系统节能分析

首先分析了集中供热热网系统能源浪费的表现和程度，进而提出了改造和完善的节能措施。     

Development of an international standard set of barley differential genotypes for Pyrenophora teres f. teres

International comparison of virulence profiles of Pyrenophora teres f . teres (Ptt), the cause of barley net blotch, is seriously restricted by inconsistencies in differential testers used among researchers. This paper reports an attempt to develop an appropriate set of differentials to standardize characterization of Ptt populations globally. Fourteen barley genotypes (Canadian Lake Shore (CLS), Harbin, c-8755, c-20019, Manchurian, Tifang, CI 9825, CI 5791, CI 9819, Beecher, CI 9214, Skiff, Prior and Corvette) were selected from among genotypes previously used as Ptt differentials. Three cultivars (Pirkka, Haruna Nijo and Harrington) were included to identify a universally susceptible control. Genotypes were inoculated with approximately 1000 Ptt isolates from Russia, Europe, Australia and Canada. The mean reaction frequency of genotypes ranged from highly resistant (CI 9819, CI 5791, c-8755 and CI 9825) to highly susceptible (Harrington, Haruna Nijo and Pirkka). The best differential abilities were demonstrated by Harbin, CLS, c-20019, Manchurian and Prior. Application of cluster analyses identified genotypes with similar reaction patterns, which supported a reduction of genotypes in the set. When combined with an algorithm comparing the ability of individual genotypes to discriminate among Ptt isolates, a further reduction of genotypes was justified. A new, concise set of barley genotypes for differentiating virulences in Ptt was formulated. It is proposed that these genotypes be adopted as the standard, international differential set to characterize and identify the virulence properties of Ptt populations across environments. The new Ptt differential set consists of the genotypes c-8755, c-20019, CI 5791, CI 9825, CLS, Harbin, Prior, Skiff and Harrington.