Sedimentary phosphate method for estimating paleosalinities: limited applicability

The sedimentary phosphate method for estimating paleosalinities was tested on argillaceous sediments from different formations and environments. Results reveal that the method cannot be used generally.     

Sedimentary phosphate method for estimating paleosalinities: a paleontological assumption

Paleosalinity values in certain rocks determined by the sedimentary phosphate method differ from salinity estimates based upon contained fossil assemblages, geochemical methods, and existing stratigraphic controls. Some anomalous values are related to the abundance of fossil organisms known to be concentrators of calcium phosphate. Because of the abundance and diversity of organisms which might introduce significant errors into paleosalinity estimates, the sedimentary phosphate method seemingly is of limited applicability.     

径流含沙量测定方法研究

目的径流含沙量是水文测验和水土流失监测中必须测定的重要参数,更是衡量水土流失程度的重要指标,简单便捷的径流含沙量测定方法是目前水土保持监测中需要解决的关键问题之一,这对于实现水土流失量的自动监测和预警,及时准确地把握水土流失强度,进而选择合理的水土保持措施,开展水土流失治理均具有重要意义。方法本文通过采集国内不同省份的土壤样品,利用室内实验,构建了称重法测定径流含沙量的基本原理,提出了计算含沙量的经验模型,探讨了称重法测定径流含沙量精度的主要因素（泥沙比重、泥水样体积、水温）。结果称重法测量径流含沙量的模型精度较高,能满足水土保持监测中径流含沙量测定的精度要求,径流含沙量在5.00 ~ 20.00 g/L时,平均相对误差 < 20.00%;径流含沙量在20.00 ~ 200.00 g/L时,平均相对误差 < 5.00%。泥沙比重对泥沙含量测定结果的影响不显著,可采用水土流失地区表层土壤平均比重（变化范围基本在2.50 ~ 2.70之间）,利用称重法模型计算出径流含沙量。泥水样体积的测定误差是影响称重法测量泥沙含量精度的关键,研制以称重法为基本原理的径流泥沙含量自动监测仪器时,准确测量泥水样的体积最为关键。温度对称重法测量径流含沙量的精度影响很小（P > 0.05）。结论称重法操作简单,精度高,在水土流失自动监测领域具有良好的应用前景。      

各向异性含水层参数估计的差分进化算法

【目的】通过分析抽水试验数据进行各向异性含水层参数估计,为各向异性含水层参数估计提供新的方法。【方法】以各向同性情况下的泰斯公式为基础,将差分进化算法应用于各向异性条件下含水层参数的估计,并将其计算结果与其他方法的参数估计结果进行比较,对不同初始参数范围下的参数估计值进行分析探讨。【结果】差分进化算法估计的参数值与其他方法估计的参数值之间有较小的差异,相对误差不到4%,且目标函数值相对更小,达到0.003 93;对于不同的初始参数范围,利用该算法均能得到满意的参数估计结果。【结论】基于抽水试验数据估计各向异性含水层参数的差分进化算法估计结果有效且可靠,算法稳定性高,寻优能力强。     

估算流域非点源污染负荷的降雨量差值法

结合我国非点源污染监测资料少的实际情况,利用我国现有的水文站降雨资料和水质资料,提出了一种简便易用的流域非点源污染负荷估算方法——降雨量差值法。与传统的径流分割法相比,降雨量差值法能利用现有水文水质资料而无需增加监测项目,即可对流域非点源污染负荷作出估算,计算过程简单,结果合理。     

用纯合基因型估计遗传力的一种新方法

本文提出了一种用纯合基因型估计数量性状遗传力的新方法。该法的试验不需设置重复,只要有若干纯合基因型在两种不同环境(如年份、地点或栽培措施)下的观测值即可,因此特别适合于作物品种资源研究或育种实践中的资料分析。文中用一个油菜实例对本法和现有唯一的用纯合基因型估计遗传力的方差分析法进行了比较,结果表明本法具有试验简单,计算容易和估值更为实际等优点。     

磷酸氢钙中钙含量测定方法的改进

主要研究了应用高锰酸钾滴定法测定磷酸氢钙中钙含量的方法,该方法准确度高,重现性好。     

腐植酸钾与磷肥施用方式对土壤磷素移动性的影响

为探明腐植酸与磷肥施用方式对土壤磷素移动性和淋失量的影响,通过室内土柱淋溶试验,分别设计了不施肥（CK）、基施腐植酸钾追施/不追施磷肥（HA-P、HA）、基施磷肥追施/不追施腐植酸钾（P-HA、P）和磷肥腐植酸钾共同基施（P+HA）共6个处理,来探讨将腐植酸水溶性肥料中的主要原料腐植酸钾与磷肥按照不同施用方式施入土壤后对土壤磷素剖面迁移能力和淋出的影响。结果表明：在相同的灌溉条件下,HA-P处理显著增加了土壤磷素的淋出,分别比P-HA、P和P+HA 3个处理的磷素淋出总量高244.08%、78.51%和35.34%,而P-HA则显著降低了土壤磷素的淋出量;P+HA和P-HA处理土壤剖面的速效磷和全磷含量均随土层深度的增加而显著增加,与P处理结果相似,而HA-P处理剖面各层土壤的速效磷和全磷含量差异较小;HA处理会使土壤磷素淋出略有增加。研究表明,腐植酸钾与磷肥等量输入时,以腐植酸钾为基肥、磷溶液进行追肥的施用方式对土壤磷素移动的促进作用最大,有较高的淋失风险,而基施磷肥、追施腐植酸钾则可以显著控制土壤剖面磷素移动,降低土壤磷素的淋出量。     

基于机载LiDAR数据的玉米叶面积指数反演

以机载LiDAR离散点云数据为数据源,基于植被冠层孔隙率与叶面积指数的关系,提出一种反演大田玉米叶面积指数的方法。对反演LAI和实测LAI进行对比分析,结果表明:基于Axelsson改进的不规则三角格网加密方法可以将地面点和非地面点分开,结合高分辨率影像能够提取出玉米冠层点云;基于孔隙率反演LAI,尼尔逊参数的选择对结果影响很大,利用扫描天顶角模拟尼尔逊参数,LAI反演结果接近于真实情况。利用机载LiDAR点云数据能精确地反演大田玉米LAI,该研究方法适用于中等高度的农作物,可以扩展到甜菜、甘蔗等其他中等高度农作物。     

区域性肉鸡保险费率厘定的实证研究

在回顾农业保险费率厘定方法的相关文献的基础上,采用参数估计法和实际生产历史法(APH),根据辽宁省北票市2008—2011实地调研数据进行肉鸡保险费率厘定。结果表明:在90%的保障水平下,保全险时北票市肉鸡保险的纯费率为1.99%;做出调整以后,在现行条款下的纯费率为1.94%;考虑保险公司经营管理费用和合理利润后,厘定出的毛保险费率为2.70%。这个费率略低于现行的江苏省3%和河南省3.75%的肉鸡保险费率,略高于现行的北京1%的肉鸡保险费率和辽宁省辽阳市2%的肉鸡保险费率。该结果可为区域性肉鸡保险费率的厘定决策提供参考。     

基于水位恢复试验数据估计含水层参数的模糊线性回归法

【目的】通过分析含水层水位恢复试验数据进行含水层参数估计,为地下水含水层参数估计提供方法支持。【方法】以现有的直线拟合法为基础,应用模糊数学知识,在考虑了地下水系统本身存在的不确定性的基础上,借助正态模糊线性回归推求各含水层参数对应的正态模糊数,通过相应的隶属函数最终给出了在不同置信水平下含水层参数的取值区间,并与其他方法的含水层参数估计结果进行了比较。【结果】基于含水层水位恢复试验数据,通过模糊线性回归,得到了不同置信水平下含水层参数的取值区间,且随着置信水平的增大,参数取值区间不断缩小;实例验证及不同方法估计结果的比较表明,应用正态模糊线性回归法求解含水层参数的方法不仅是可行的,而且更符合实际情况。【结论】用基于水位恢复试验数据的模糊线性回归法估计含水层参数,因充分考虑了含水层参数的不确定性,故估计结果更为准确可靠。     

农业机械化在农业生产中贡献的一种测算方法

在现有文献研究的基础上 ,假定技术进步为希克斯中性的前提下 ,推导出增长速度方程 ,给出增长速度方程在各种投入要素的产出弹性是变化的情况下的参数估计方法 ,进而给出测算农业机械化在农业生产中贡献的测算模型。     

A method for estimating the number of hidden neurons in feed-forward neural networks based on information entropy

The number of hidden neurons of feed-forward neural networks is generally decided on the basis of experience. The method usually results in the lack or redundancy of hidden neurons, and causes the shortage of capacity for storing information or learning overmuch. This research proposes a new method for optimizing the number of hidden neurons based on information entropy. Firstly, an initial neural network with enough hidden neurons should be trained by a set of training samples. Secondly, the activation values of hidden neurons should be calculated by inputting the training samples that can be identified correctly by the trained neural network. Thirdly, all kinds of partitions should be tried and its information gain should be calculated, and then a decision tree for correctly dividing the whole sample space can be constructed. Finally, the important and related hidden neurons that are included in the tree can be found by searching the whole tree, and other redundant hidden neurons can be deleted. Thus, the number of hidden neurons can be decided. Taking a neural network with the best number of hidden units for tea quality evaluation as an example, the result shows that the method is effective.     

肉制品中丁烯磷残留量检验方法研究

论述了样品前处理的微量化学法原理 ,设计了简便提取、净化肉制品中丁烯磷残留量的GC -FPD测定方法     

利用~(32)P示踪技术研究土壤磷素活性剂对大豆吸收土壤和肥料磷素量的影响

应用 3 2 P示踪技术研究了土壤磷素活化剂在磷肥肥效方面的影响。结果表明 ,施用土壤磷素活化剂可增加土壤磷素和肥料磷素的供应强度 ,促进大豆对土壤磷素和磷肥磷素的吸收。     

Service-oriented approach for modeling and estimating reference evapotranspiration

Software used for estimating reference evapotranspiration (ET₀) has been developing in various directions. The main goal of this paper is to present an approach based on Service-Oriented Architecture (SOA) paradigm for modeling and estimating ET₀. The FAO-56 Penman-Monteith (FAO-56 PM) and Hargreaves equation are used for estimating monthly ET₀.The weather data for this study were obtained from CIMIS for Davis weather station. The FAO-56 PM and Hargreaves ET₀ values estimated using ET Web service were compared to corresponding CIMIS PM ET₀ estimates. The proposed model based on Web services implemented to the FAO-56 PM and Hargreaves equations has good performances and can be used in estimating ET₀ and has ability to complete missing weather data.     

甜瓜果实体积与表面积的估算方法

以黄河蜜甜瓜为试材,以排水法测定的体积和纸重法测算的表面积为依据,对椭球体体积与表面积计算公式进行了修正,建立了用纵、横半径估算厚皮甜瓜果实体积与表面积的新方法。检验结果表明,用2个修正计算公式估算的甜瓜体积和表面积值与实测结果之间无显著差异。修正公式可用以快速而准确地估算厚皮甜瓜果实的体积与表面积。     

Software for estimating reference evapotranspiration using limited weather data

The FAO-56 Penman-Monteith combination equation (FAO-56 PM) has been recommended as the standard equation for estimating reference evapotranspiration (ET₀). The FAO-56 PM equation requires the numerous weather data that are not available in the most of the stations. The main goal of this paper is to present the software for estimating reference evapotranspiration, focusing on the feature of using limited weather data. This is simple Windows-based and user-friendly software provides methods to estimate extra-terrestrial radiation, maximum sunshine hours, daily net radiation and daily/monthly ET₀. The program is written in C# and includes comprehensive technical documentation. The software is available for free download.The weather data for this study were obtained from CIMIS for Davis weather station. The reduced-set FAO-56 PM approaches and adjusted Hargreaves equation were compared to the full-set FAO-56 PM equation. The FAO-56 reduced-set PM ET₀ estimates were in closest agreement with FAO-56 full-set PM ET₀ estimates. The adjusted Hargreaves equation (AHARG) was found to be in very good agreement with the full-set FAO-56 PM. This program is the first software facilitating calculation of ET₀ only with air temperature parameter.