桃麦间作条件下对小麦进行分区的研究

研究提出了在桃麦间作条件下对小麦进行分区研究的方法,并以间作小麦的产量以及产量构成因素作为分区指标,利用有序样的聚类方法,根据距离桃树远近不同,将小麦种植区划分为冠下区G1、近冠区G2和近冠区G3。     

基于聚类分析法的西南丘陵山区县域土地利用分区研究

土地利用分区是土地利用区域差异性的客观反映,是土地利用规划的核心内容之一。为了对西南丘陵地区县域土地利用及未来发展方向提供理论指导,以重庆市江津区为例,通过采用构建土地利用分区指标体系的方法,借助SPSS软件,对聚类指标体系表进行赋值并对数据进行聚类指标标准化处理,将标准化后的数据作为基础数据,利用系统聚类分析功能对江津区土地利用进行分区。结合分区结果及兼顾区域连续性以及江津区今后社会经济发展,将该区域分为3类：北部城镇高度发达区、中部发展潜力区、南部农林生态区。根据各区域的相似性和差异性,提出了各区域土地资源开发利用中存在的主要问题和未来发展方向。结果表明,聚类分析法是研究西南山区县域土地利用分区的有效方法,该研究是土地利用分区从定性到定量发展的有益尝试。     

不同山茱萸种质资源形态和ISSR遗传多样性研究

利用形态特征和ISSR标记对35份山茱萸种质资源进行遗传多样性分析,利用NTSYSpc-2．11F软件分析遗传相似系数,UPGMA方法聚类,构建亲缘关系系统图。结果表明,35份山茱萸在9个性状上差异明显;分子标记中9条引物共得到条扩增条带179条,其中有164条呈现多态性,占91．6％,遗传相似系数变化范围O．575-0．877。对其进行数据化处理后聚类,35份山茱萸材料可划分为2个类群6小组,材料的聚类结果与地理分布、形态特征有一定的相关性。     

水电站工程水土流失预测存在的问题及对策

开发建设项目水土流失量预测是水土保持方案编制的依据和关键,针对水电站工程水土流失预测过程中出现的种种问题,如预测分区的混乱,预测面积不准确,预测时段划分不正确等,提出了相应的对策。给出了水土流失预测项目区划分图,对预测过程中流失系数的算法进行了分析,作者建议从侵蚀因子、选择类比法来或查阅相关水文资料确定流失系数。     

基于SSR标记的苹果砧木资源的亲缘关系分析

本研究利用SSR方法对46个苹果砧木资源基因组DNA进行分析,了解了目前生产上常用砧木在野生资源中的遗传背景分布,并为进一步的砧木育种亲本选择提供了参考依据。本研究选用筛选出的具有较高多态性的31对引物,获得了111个多态性位点。通过NTSYS软件进行相似性系数计算,46个苹果砧木资源的相似系数分布在0.585 6~0.964 0之间,利用UPGMA法构建聚类树状图,将供试砧木品种划分为4个类群:西府海棠单独划为一类;以山荆子系为主的7个品种为第二类;三叶海棠b、丽江山定子和平邑甜茶聚为第三类;第四类群主要是新疆地方品种、楸子类和培育的砧木品种,共32个品种,聚类又分为4个组,在第四组中大部分的新疆地方品种与楸子类互为交叉聚类在一起,而M9、PAJAM2、Luo 2和Luo 6等培育的砧木品种与花红、新疆野苹果和西蜀海棠等单独聚在一起。     

多种分类器在农用地分等中的应用及其用法改良

以广东省第二次土壤普查成果资料为主要数据源,选取贝叶斯决策、BP神经网络、概率神经网络、聚类等分类方法分别对数据源进行分类;并且,笔者为了充分利用有监督学习分类准确率高和无监督学习无需标定的学习样本的优点,提出了基于监督--非监督的聚类算法,然后对上述五种方法的评价结果作了比较分析;实验表明文章提出的基于监督--非监督聚类方法只利用少量的有标定学习样本,即可得到较高的分类准确率,特别在少量样本时,该方法能得到比贝叶斯决策方法、BP神经网络和概率神经网络等监督学习方法更好的土地评价结果;在实际应用中,可以尝试结合监督和非监督学习的方法,实现分类正确率和获取大量有类标签的样本之间的折中。     

我国部分玉米自交系遗传关系和遗传结构解析

玉米自交系遗传关系和遗传结构的解析,对自交系类群划分和杂交组配具有重要的指导意义。本文选用玉米基因组的112个SSR标记对我国97个玉米自交系进行遗传关系和遗传结构分析,并评价了遗传距离聚类和模型聚类方法在玉米自交系遗传关系研究中的应用价值。结果表明,模型聚类方法更适于玉米自交系的遗传关系研究。解析自交系的遗传基础发现,各类群中均有大量自交系含有其他类群的遗传成分。根据模型聚类结果,97个自交系被划分为PB、Reid、塘四平头和旅大红骨4个类群。Reid群与旅大红骨群的遗传关系最近,与塘四平头群遗传关系最远。为了实现杂种优势模式的简化,4个类群可被简化为3大种质类群[A(旅大红骨群与Reid群)、B(PB群)、C(塘四平头群)],或2大种质类群[A(旅大红骨群、Reid群、PB群)、B(塘四平头群)]。研究结果为自交系的改良和利用及杂种优势模式确定提供了理论基础。     

传感器网络同步态的节点故障诊断算法

首先介绍了复杂网络同步态的概念,以传感器量测数据为节点,定义了随时间动态变化的传感器网络,采用数学分析方法定量描述了传感器网络的动力学机制,给出了传感器网络同步态的数学定义、计算方法及其实际的物理含义。理论推导表明,同步态从全局角度评价传感器网络的健康程度,以量测数据距离关联性定义复杂网络的耦合矩阵A=（a_ij）_N×N,并以该耦合矩阵零特征值对应的左特征向量（ξ₁,ξ₂,...,ξ_N）来刻画传感器网络节点的局部细节信息,进而衍生出基于传感器网络同步态的节点故障诊断算法,实现传感器网络的故障诊断。实验仿真了由100个传感器组成的复杂网络,采集了在稳定运动60 s期间的的量测数据,每个量测数据长度为5 000,其中有3个传感器处于间歇增益故障状态,以此来验证基于传感器网络同步态的节点故障诊断算法的有效性。结果表明,该算法不仅可以很好地跟踪整个传感器网络的工作状态,实时监测每个传感器网络节点的故障,而且可以利用传感器网络节点故障之间的相关性有效地识别出传感器量测数据的异常是由外界量测对象的改变还是由传感器本身故障引起的。该算法为全局评估传感器网络的工作状态和监测网络节点的局部故障提供了一个新颖可行的研究思路,期望为相关领域的研究学者提供有益的参考。     

南平烟区植烟土壤中、微量养分丰缺分区及烤烟施肥区划研究

通过采集、测定南平烟区代表性植烟土壤中、微量元素含量状况,借助GIS、GPS与地统计学模型（Geo-statistic）集成,研究其空间分布状况,并作出分区评价。结果表明：土壤有效锌、水溶性氯平均含量分别为2.55 mg/kg、20.22 mg/kg,含量中等以上面积分别占总耕地面积的94.71%、45.15%;交换性钙平均含量分别为531.69 mg/kg,含量较低和中等的面积占93.68%;交换性镁平均含量80.09 mg/kg,丰富面积占70.61%;有效硫平均含量35.30 mg/kg,含量中等以上面积占89.45%;有效硼平均含量0.26 mg/kg,含量低值面积占64.60%。交换性钙和有效锌可划分为2个类区,水溶性氯可划分为4个类区,交换性镁和有效硫、有效硼则可划分为3个类区。同时,根据土壤碱解氮、速效磷和水溶性氯等主要养分的分布分区状况和丰缺程度,提出了8个施肥分区和5个烤烟专用肥分区,并根据每个分区的特点给出了相应的专用肥配方建议,实现烤烟统一、简化施肥。     

聚类分析

由于农业研究的复杂性,使一些分类的问题长期不能定量地、客观地、科学地加以解决。随着科学技术的发展,这些分类的研究,正在从传统的、主要靠经验和定性的处理方式,向应用数学的方法和使用电子计算机进行定量化的处理方式转变。这些数学方法中,聚类分析是一种很重要的方法。聚类分析,是一种多元统计分类法。根据分类前是否清楚所研究的事物需要分成多少类型。聚类分析,可以划分为系统聚类和动态聚类。系统聚类适于事先并不清楚应分成多少类型的问题,形成的类正是分析的结果;动态聚类解决事前已初步确定,大致可分成多少类的问题。再由研究中需对何种变量(样本     

Graph clustering of Piper nigrum L. (black pepper)

A profound degree of morphological variation exists among the cultivars of Piper nigrum cultivated in Kerala State, South India. Fifty one cultivars of this crop species from the State were subjected to graph clustering by the ‘Graph Theory’ model, based on 27 morphological characters, both qualitative and quantitative, aimed at clustering them into groups with an appreciable degree of intracluster discreteness and intercluster distance. The result was presented in a ‘Skyline Plot’. Ten C-clusters were formed at the c-value of 0.46 corresponding to a fairly high moat value. The number of members from different clusters ranged from 3–8. Distribution of various characters among the clusters formed, shows a considerable degree of intracluster similarity (connectedness) and intercluster distance (isolation). The present graph clustering is significant as it provides reliable clues for selecting parental cultivars with fair degree of genetic difference, from clusters exhibiting appreciable isolation, for future intervarietal hybridization programmes in the crop. This revised version was published online in July 2006 with corrections to the Cover Date.     

直接接触式换热器传热性能优化

建立了以容积换热系数为目标函数,工质流率U₀、喷头喷孔直径d_i、导热油液位高度Z为决策变量的直接接触式换热器性能优化模型,同时进一步将液滴群行为与传热协同关系作为约束条件引入优化模型中,重点分析该约束条件对优化过程及结果的影响。运用遗传算法对原模型和补充模型进行了优化分析,结果表明：原模型优化后的容积换热系数达到了初始值的6.7倍;而补充模型最优值的迭代次数比原模型减小了约55%,同时最优值比原模型提高了0.3%。所以该约束条件不仅提高了迭代速率,还提高了寻求全局最优值的概率,使得最优解更逼近全局最优值。     

正交试验法优化玛咖含片配方

应用正交试验法优化玛咖含片配方,并考察玛咖含片的制备工艺及其实际配方生产中产品的性能。采用L₉(3⁴)正交试验法,以玛咖含片的感官评价为指标,选出玛咖含片的最适宜工艺条件、并对最佳条件下产品的稳定性、重金属和微生物进行考察。玛咖含片口感的最佳工艺条件为：玛咖粉为80%,红景天粉为12%,当归粉为6%,玛咖含片的口感综合指标为246、产品的各项重金属含量符合GB16740标准中的规定、保存12个月之间玛咖含片的色泽,外观形状,脆碎度,崩解时间没有发生明显的变化、微生物也没有增加并其含量满足食品安全要求。工艺及质量控制方法简便可行,稳定可靠,此工艺研究已获得国家专利（专利号：ZL200810233796.X）,产品的重金属含量和微生物为其质量标准提供了实验基础。     

Genetic relationships among species and cultivars of Pistacia using RAPDs and AFLPs

The genus Pistacia (Anacardiaceae) includes 11 species divided into four sections, according to leaf characters and nut morphology. Recently two monophyletic groups have been proposed by using cpDNA,Lentiscus and Terebinthus,containing evergreen and deciduous species, respectively. In the present work molecular markers, derived from two different methods, RAPD and AFLP, are used to study the relationships of native and introducedPistacia species present in Greece. According to the cophenetic correlation coefficients best results for both methods were obtained by using the Jaccard algorithm and the UPGMA clustering method. However, phenograms were constructed using the NJ method (r_cs= 0.987 for RAPDs and r_cs= 0.982 for AFLP), since it is less sensitive against varying mutation rates. Correlation among the genetic similarity (GS) matrices for the two methods was high(r = 0.941). The AFLP and RAPD phenograms were comparable with minor clustering differences. According to our results, two main branches are obtained, one containing the evergreen species P. lentiscusand the resin producing P. lentiscuscv. Chia (cultivated only in the island of Chios), and the other branch containing the deciduous species P. terebinthus,P. palaestina and P. vera, P. chinensis was clustered either with the evergreen species (RAPD data) or with the deciduous species (AFLP data). P. palaestina is clustered to P. terebinthus and can be considered as a subspecies of P. terebinthus, since its GS values are close or smaller than GS values of entries within species (P. vera). The four female cultivars were found to have a narrow genetic basis, probably related to cultivar ‘Nazareth‘ with Syrian origin. This revised version was published online in July 2006 with corrections to the Cover Date.     

A method for testing drought tolerance in <Emphasis Type="Italic">Fragaria</Emphasis> based on fast screening for water deficit response and use of associated AFLP and EST candidate gene markers

Drought stress is one of the most important environmental factors that limit plant growth and development, thus reducing yield. The objective of the present research was to correlate the genetic structure of different Fragaria genotypes, as assessed by Expressed Sequence Tag (EST) and Amplified Fragment Length Polymorphism (AFLP) markers, and plant responses to drought stress. Firstly, physiological parameters related to the plant response to drought stress such as leaf relative water content (RWC) and water losing rate (WLR) were measured. WLR and RWC were compared for 20 cultivars of the octaploid Fragaria × ananassa, two ecotypes of the diploid species F. vesca and one octaploid species F. chiloensis. These parameters could discriminate genotypes showing a contrasting response to water stress. Secondly, AFLP and ESTs were compared in terms of their information content and efficiency in the study of genetic diversity and relationships among these 23 Fragaria genotypes. To evaluate the genetic basis for the observed variation in the measured physiological parameter, the effect of specific AFLP/EST loci on WLR and RWC for the different Fragaria genotypes was quantified by Kruskal–Wallis analysis. By Mantel testing, the hierarchical clustering of the Fragaria genotypes based on associated EST or AFLP markers was compared to the observed eco-physiological relevant grouping. A better discriminating capacity for associated markers was noted, enabling a functional marker selection approach to screen the strawberry gene pool for drought tolerance. Correlation of EST markers to leaf RWC and WLR enforces them as potential candidate genes in control of plant responses to drought stress in Fragaria sp.     

Quantification and Simulation of Grazing Impacts on Soil Water in Boreal Grasslands

We conducted a 2‐year study in central Alberta to quantify and simulate the soil water status of boreal grasslands under three grazing systems using wapiti (Cervus elaphus Canadensis), viz. (1) ungrazed control (UNG), (2) high intensity [4.16 animal unit month per ha (AUM) ha^?1 ] short‐duration grazing (SDG) and (3) moderate intensity (2.08 AUM ha^?1) continuous grazing (CG). Soil water was measured from May 1997 to September 1998 to a depth of 15 cm. Total annual precipitation in 1997 and 1998 was 494 and 429 mm respectively. In both years grazing treatments reduced soil water. Soil water content under SDG was significantly (P < 0.05) lower than CG. Simulation of soil water on each grazing system was conducted using PASTURE, a simple compartmental system dynamics model. Evaluation of the model was conducted using statistical criteria that included calculation of average error, root mean square, coefficient of residual mass and modelling efficiency and comparing these statistics against optimal values. Although the model under‐predicted soil water, simulations of soil water for grazing treatments in both years were closest to measured values with modelling efficiency (how well observed values are close to simulated values) up to 68 %.     

Changes in nutritive value of alfalfa (Medicago × varia T. Martyn) and Festulolium (Festulolium braunii (K. Richt) A. Camus) under drought stress

Legume–grass mixtures showed a weaker response to adverse environmental conditions than to monocultures. A yield decrease due to the scarcity of water is well documented, while the impact on the food value is inconsistent. Therefore, we undertook studies to assess the impact of water deficit in the soil on the content of the nutrients in alfalfa and Festulolium grown in monoculture and in mixture. A pot experiment was carried out in 2012–2014 in a completely randomized design, with four replications. The research was carried out at two levels of soil moisture: 70% field water capacity FWC (optimal conditions) and 40% FWC (drought stress). We found that the effect of drought stress on the food value of alfalfa and Festulolium was smaller than on the yield. Water deficit caused a significant yield decrease, the biggest in alfalfa in monoculture. Drought stress significantly reduced the content of crude fibre, the contents of crude protein and crude fat tended to increase. The influence of stress on water‐soluble carbohydrates content was not determined. Nutrient content was varied depending on a species. Introducing alfalfa as a component to a mixture with Festulolium caused a significant yield increase and improved the nutritional value of dry matter.     

THE OPTIMAL DESIGN AND ENGINEERING APPLICATION OF DISTRIBUTION

This paper introduces the metod of optimal design of municipal water distribution,The main points are the theory,mathematical model,program frame figure and example in practice of the optimal method of hydraulics.The program is applicable to the design and calculation of the pipe network in a city. It gives a simple and convenient calculation method for multiple-scheme design and scheme cmparison of water supply system.     

Nondestructive detection of insect infested chestnuts based on NIR spectroscopy

Insect feeding is a significant postharvest problem for processors of chestnuts (Castanea sativa, Miller). In most cases, damage from insects is ‘hidden’, i.e. not visually detectable on the fruit surface. Consequently, traditional sorting techniques, including manual sorting, are generally inadequate for the detection and removal of chestnuts with hidden damage. For the most part, the only method currently used by processors is a flotation system, in which chestnuts are placed in salt water and those that float are discarded. Flotation is unreliable, and a more effective method for detection of insect damage would benefit industry and consumers alike. In this study, the feasibility of using NIR spectroscopy to detect hidden insect damage is demonstrated. Using a genetic algorithm for feature selection (from 2 to 6 wavelengths) in combination with a linear discriminant analysis routine, classification error rates as low as 16.81% false negative, 0.00% false positive, and 8.41% total error were achieved, with an AUC value of 0.952 and an Wilk's λ of 0.403 (P < 0.001). A Savitzky–Golay first derivative spectral pretreatment with 13 smoothing points was used. The optimal features corresponded to Abs [1582 nm], Abs [1900 nm], and Abs [1964 nm]. These results represent an average of 55.3% improvement over a traditional flotation sorting system.     

Temporal stability of multivariate genetic divergence in cacao ( Theobroma cacao L.) in Southern Bahia conditions

Stability of the genetic divergence among five non-commercial cacao cultivars at advanced ages was investigated over a five-year period (1986–1990). Cluster analysis was performed on five yield components measured on harvests from each crop year and on the data pooled over five years. The temporal stability was assessed by using clustering procedure, which involved the calculation Mahalanobis distance (D²) and of Tocher's algorithm applied to the distance matrix. The comparison of D² and of clusters based upon pooled analysis, and taken as the standard, with D² values and clusters obtained from each year showed a stable clustering pattern in the most favourable year. For the rest of the years, inconsistency in number and composition of clusters formed was observed. An optimum environment was shown to be important for better expressing divergence by D². Consequently, the evaluation of the genetic divergence among the studied cultivars may be conducted based on a single favourable year. This will result in considerable savings in man power, financial resources, and time which would be wasted should the evaluation be extended for several years.