三种养殖模式下日本鳗鲡(Anguilla japonica)养成品体色和肌肉品质的差异

随机选取池塘专养(M1)、日本沼虾套养(M2)以及水库放养(M3)三种养殖模式养成的肛长(25.91±3.26)cm的日本鳗鲡作为研究材料, 比较研究了三者间在表皮色差、背肌组织物理特性和肌肉营养成分组成及含量上的差异。结果表明: (1) M1表皮色差与M2、M3均具显著差异(P<0.05), 三者背、腹间的体色差异程度呈M1>M2>M3 (P<0.05); (2) 背肌物性指标中均具显著差异的为粘着性、弹性和回复性, 前者测定值呈M1>M3>M2 (P<0.05), 后两者均呈M3>M1>M2 (P<0.05), M3背肌最发达, M1纵肌肌束纤维排列较M2紊乱; (3) 肌肉营养成分中仅水分和灰分含量均具显著差异, 依次呈M3>M1>M2 (P<0.05)和M3>M2>M1 (P<0.05), 蛋白质含量高于脂肪含量的仅为M3; (4) 三者间肌肉脂肪酸、氨基酸组成均完全相同, 含量排序也均基本一致, 但多种不饱和脂肪酸含量却均具显著差异(P<0.05)。     

Pyrite surface interaction with selected organic aqueous species under anoxic conditions

The interaction between low-molecular weight organic compounds and pyrite under anoxic conditions has been studied using a combination of electrophoresis and batch sorption experiments. The results suggest that acetate, carbamide, ethylamine, formamide, purine, D-ribose, and adenine, as well as the amino acids alanine, cysteine and glycine, interact within the electrophoretic shearplane of the pyrite surface. The observed surface interaction between the negatively charged surface of pyrite and the organic aqueous species takes place regardless of the formal charge of the aqueous species of interest. This indicates that the interaction of organic molecules with pyrite surfaces under anoxic conditions is dictated by interactions with specific surface sites (thiol or iron surface sites) rather than electrostatic forces. Dissolved metals typically enhance the interaction of the organics species. This enhancement is either due to an alteration in the distribution of thiol and iron groups on the pyrite surface or by the formation of ternary surface complexes.     

区域自然资源可持续利用创新模式研究

区域可持续发展要求有源源不断的后续资源供应为保证,资源问题是区域发展的核心问题之一。本文界定了区域自然资源可持续利用的概念,构建了区域自然资源可持续利用模式并进行了实证分析。     

Crack propagation analysis with Galerkin boundary element method

This paper describes the application of symmetric Galerkin boundary element methods (SGBEM) for the analysis of a 2D crack propagation problem. The sub-domain SGBEM for crack problem is derived. The coefficient matrix is completely symmetric. Cohesive crack model is used to simulate crack propagation. The increment control method for crack propagation and the method for unknown crack propagation path have been derived for high-order element. Two-stage interpolation method called the ‘quasi-higher order element method’ (QHOEM) is then proposed to solve the double integrals. In the initial stage, it uses higher order elements to interpolate the field variables, and for the numerical integration involved, it further uses interpolation functions to decompose the higher order elements into lower order elements so that the existing analytical integration can be applied. A finite rectangular plate containing a centre crack growth and four-points bending beam problem have been analysed to check the accuracy of the proposed method. For actual application, a dam buttress with an edge crack has been analysed and the results are found to be in agreement with the other numerical and experimental results. Copyright © 2004 John Wiley & Sons, Ltd.     

Soil respiratory and enzyme activities in leachate-contaminated soils with different application rate of cow manure compost: a laboratory study

The experiment was conducted to evaluate the effects of cow manure compost (CMC) application on respiratory and enzyme activities of leachate-polluted soils. Soils treated with various levels of leachate (0, 12.5, 25, 37.5, and 50 ml leachate per 300 g soil) were amended with 0, 25 and 50 g CMC, respectively. Soil pH, respiration and enzyme activities were evaluated by regularly repeated sampling. Addition of CMC neutralized pH and maintained it within the range of 6.4–6.7 in a long run. Respiration was increased neither by leachate nor by CMC. This probably results from deterioration of soil compaction, biotoxicity of leachate, or increased fungi proportion. Enzyme activities increased with increasing CMC application but decoupled with leachate addition rate, reasonably attributed to pH neutralization and high content of humus in CMC. Thus, pH value and humus content could be considered as key items affecting soil enzyme activities.     

串联SRME在涠西南地区多次波衰减中的应用

在浅水区域的海洋地震勘探中,海底与水面波阻抗差异较大,形成了大量的短周期海底多次波（鸣震）及微屈多次波,严重影响了地震资料的真实性与可靠性,此类多次波一般采用自由地表相关多次波压制（SRME）;涠西南某工区由于基底较浅且与老地层波阻抗差异较大,所以除海面与海底外存在第三个多次波源,尤其在基底处产生的海底微屈多次波,离基底较近,很容易被误认为是基底,此类多次波采用传统的SRME方法无法有效压制,笔者采用基于波动方程模型与褶积模型串联SRME对其进行压制,实际资料处理结果显示该方法对多次波压制效果较为明显。     

中国区域创新来源的空间异质性研究

基于经济普查数据,应用地理加权回归模型实证研究了中国区域创新来源因素对创新绩效影响的空间异质特征。结果发现当前中国区域创新主要来源是自主研发,国内技术引进和技术吸收对区域创新有正向作用,外国技术引进、出口、外国直接投资存在一定负效应。不同的省域,创新来源因素对创新绩效的影响存在空间异质。创新来源因素对区域创新的影响大体呈现从东部发达地区向西部后发地区梯度递减特征。在东、中部地区,自主研发成为主要创新来源因素,正效应显著;西部地区的创新来源除自主研发,国内技术转移和吸收仍发挥重要作用,地理加权回归较好揭示了创新影响的空间异质特点。     

近40年来中国降水量、雨日变化趋势及与全球温度变化的关系

近40年来中国降水量的空间分布与相应时段的雨日数空间分布较一致;年降水量变化趋势主要呈现东北-西南向“＋、-、＋”分布型,其中以西部地区和长江三角洲的增加和华北及川东地区的减少趋势更加显著.对季降水来说,除了冬季降水量场表现为绝大部分地区为正趋势外,其它三季变化都较复杂;绝大部分地区年雨日数的趋势系数是负值,就是说雨日数总的趋势是减少的,全国范围内秋季雨日数明显呈现减少的趋势;夏季强降水日的平均频数介于0～11之间,最大值位于西南地区的西部,最小值则位于南疆地区;无论是降水量场还是雨日数场都与全球温度距平存在显著相关,只是后者的显著性水平高于前者.     

A fast marching method for reservoir simulation

We present a fast marching level set method for reservoir simulation based on a fractional flow formulation of two-phase, incompressible, immiscible flow in two or three space dimensions. The method uses a fast marching approach and is therefore considerably faster than conventional finite difference methods. The fast marching approach compares favorably with a front tracking method as regards both efficiency and accuracy. In addition, it maintains the advantage of being able to handle changing topologies of the front structure. This revised version was published online in July 2006 with corrections to the Cover Date.