辽河流域水污染防治规划实施状况分析

对辽河流域"九五"、"十五"、"十一五"期间的水污染防治规划主要内容及目标指标完成情况进行了介绍,阐述了各规划的流域面源污染控制的行动方案及重点工程,提出了辽河流域水污染防治"十二五"规划的初步思路。     

山区土地利用总体规划环境影响评价

根据＂压力—状态—响应＂模式,按照＂土地需求压力—土地状态变化—响应即环境影响＂思路,分析探讨了土地利用总体规划环境影响指标体系,运用耕地需求压力指数、城镇用地需求压力指数等7个指标,探讨了土地规划实施后可能产生的环境影响。结果表明,与以往土地利用规划环境影响评价指标不同,该文提出土地利用规划环境影响评价的7项指标真正从整体上揭示了土地利用规划对环境的综合影响,符合规划的宏观性、综合性和超前性特征,避免了规划环评与项目环评的雷同,具有较强的实用性和科学性,应用于贵州省土地利用总体规划环境影响评价,效果较好。     

基于动态规划算法的农村无线基站最优传输路径的研究

对农村无线基站的传输方式进行研究,将动态规划算法应用于农村无线基站传输路径的选择上,提出了切实可行的获取传输最优路径的数学模型,并通过仿真证明了其优越性。     

Prolog在过程性问题求解中的应用

本文讨论了Prolog语言的主要特点和基本结构,针对实际应用中出现的过程性问题给出了用Prolog谓词和内部运行机制来表示结构化程序设计语言中的三种控制结构,使得Prolog可以更有效地求解问题。     

Large-scale screening for maize drought resistance using multiple selection criteria evaluated under water-stressed and well-watered environments

A total of 550 maize inbred lines collected from global breeding programs were evaluated for drought resistance under both well-watered and water-stressed environments. The evaluation was based on multiple measurements of biomass taken before and after the drought stress was applied using the normalized difference vegetation index (NDVI), along with other selection criteria including anthesis-silking interval, leaf senescence, chlorophyll content, root capacitance, final grain yield, and grain yield components. Kernel weight was the most stable trait under drought stress. Correlations between the primary trait (grain yield) and the secondary traits, except the root capacitance and ASI under water-stressed condition, were all significant. Root capacitance had relatively low heritability and low genetic correlation with other drought resistance criteria, and is not recommended as a drought resistance criterion. Significant reduction of NDVI values measured in the afternoon when the leaves became rolling, compared to those measured in the morning when the leaves were open, provides a reliable index for leaf rolling, which however was not significantly correlated with grain yield. NDVIs measured across different developmental stages were highly correlated with each other and with most of the secondary traits as well as, grain yield, indicating that NDVI can be used as a secondary trait for large-scale drought resistance screening. Regression models built based on non-yield drought criteria and yield components explained about 40% and 95% of the variation for the grain yield, respectively. Some maize lines developed in China for temperate regions showed strong drought resistance comparable to tropical maize lines when tested under tropical condition, indicating that temperate lines with a wide adaptability can be used in drought resistance breeding for both temperate and tropical environments.     

随机反应扩散神经网络的鲁棒稳定性

研究一类具有分布时滞和反应扩散的随机细胞神经网络,通过构造Lyapunov泛函,并利用It公式以及线性矩阵不等式（LMI）,得到不确定系统鲁棒稳定的充分条件.     

数量性状基因定位研究中若干常见问题的分析与解答

QTL作图是基因精细定位、克隆以及有效开展分子育种的基础,在利用QTL作图开展数量性状基因定位研究的过程中经常会碰到一些问题,与统计方法有关的一些问题包括LOD的统计学意义是什么？检测QTL的可信度和LOD临界值的关系是什么？如何评价不同的QTL作图方法？提高QTL检测效率的途径有哪些？与遗传参数估计有关的一些问题包括QTL的贡献率是如何计算出来的？如何确定QTL有利等位基因的来源？选择基因型分析的有效性如何？复合性状是否适宜于QTL作图？与作图群体及遗传图谱有关的一些问题包括QTL作图群体中表型数据是否要求服从正态分布？加密标记是否可以显著提高QTL检测功效？缺失分子标记对QTL作图有什么影响？奇异分离标记对QTL作图有什么影响？文章试图结合笔者多年研究工作对这12个有共性的常见问题做出分析和解答,以供科研工作者参考。     

ZPXG-18型转盘斜刮式自动光电数粒仪和千粒重仪的设计

依据新发现的使粒料自动排序和隔距的转盘斜刮原理,设计和研制了ZPXG-18型转盘斜刮式自动光电数粒仪和千粒重仪。让无序的粒料或种粒进入有斜槽和弧槽的槽盘中,在底部转盘带动下被斜刮而移行、自动整齐排序和产生粒间距,获得光电计数所需的可靠透光间隙,并通过预置和复检二次计数实施数粒。试验表明：(1)每轮预置计数误差数小于1~2粒,而复检计数与实际粒数的误差率小于0.04%;(2)计数速度可达50 粒·s-1;(3)颗粒适用范围0.5~18.0 mm;(4)试验中未发现供试颗粒破损现象;(5)结构简单可靠,无电磁振动噪声等;(6)其原理还可以应用或开发一些既要精准计数又需防止颗粒破损的数粒设备和机械。     

基于LabVIEW模糊自适应PID的实现

通过LabVIEW与MATLAB进行混合编程的方式,借助两软件各自的优势,设计出具有模糊自适应PID控制算法的虚拟仪器,并对不同的对象特性进行控制系统的仿真与三容水箱液位的实时测控。实验结果表明,模糊自适应PID控制系统的控制效果良好,具有较强的鲁棒性。     

Seasonal Trends in Flavor Quality of Channel Catfish,Ictalurus punctatus,from Commercial Ponds in Mississippi

Seasonal trends in types and intensities of fish flavors were determined for channel catfish, Ictalurus punctatus, from 10 ponds located on a commercial farm in west-central Mississippi. Fish were sampled bimonthly from July-September, 1990 and monthly from October, 1990-July, 1991. Sensory evaluation indicated that, on a yearly basis, 19% of ponds could be considered on- flavor. Off-flavors were strongest from July through September when 76% of ponds had fish tainted by 2-methylisoborneol (MIB). In nine ponds, the onset of MIB off-flavor episodes could be correlated with the presence of an MIB-producing cyanobacterium Oscillatoria chalybea. In seven ponds, fish lost the MIB off-flavor within 3 to 8 weeks after the fist date in September that 0. chalybea was noticed to be absent from the water. In June, 0. chalybea reappeared and caused MIB off-flavors in eight ponds. During the winter and spring, ponds were affected by woody (22%) and decay (25%) offflavors. The most prevalent algal species-Raphidiopsis brookii, 0. aaardhii. and Microcystis aeruginosa-were not associated with off flavor problems. On average, MIB off-flavor episodes lasted for 115 days (range: 27-344), and seven ponds were considered free of off-flavors for an average of 74 days (range: 14-140) in October, November, and December.