基于Web的海洋计量检测实验室管理信息系统设计

介绍基于Web的海洋计量检测实验室管理信息系统的规划、分析与设计,采取了Browser／Web Server、JSP、JDBC和Jasper Reports等技术开发了本系统。阐述了本管理信息系统的体系结构、子系统划分,以及相关技术、安全策略、实施和运行机制,着重讨论系统需求、系统解决方案及数据库设计和程序设计的要点。     

溶质施放部位对红壤坡面溶质迁移特征的影响

以非吸附性溴离子为示踪剂,采用室内模拟降雨方法研究间歇降雨和施肥部位对红壤坡面产流、产沙以及溴离子迁移特征的影响。结果表明,降雨特征相同条件下,3次降雨的总径流量无明显差异,但第3次降雨形成的产沙量分别是第1次和第2次的7倍和2.2倍,这表明因前期含水量的提高而降低了土壤抗冲性是红壤侵蚀的主要原因之一;径流溴离子浓度随时间变化均呈幂函数衰减,与施肥部位无关;施肥部位越靠近坡底,径流溴离子初始浓度越高且衰减速度越快;溴离子流失数量与施肥距离呈显著正线性关系。通过估算3次间歇降雨径流中溶质流失数量的来源发现,淋溶到坡面土壤中的溴离子再次参与径流流失的数量,其平均比重从81.61%提高到了93.76%,这表明施加在上坡部位的肥料被淋溶后对后期径流养分流失的贡献十分显著。     

土壤优先流运动的活动流场模型分形特征参数计算

活动流场模型分形特征参数控制着优先流的产生和发展,因此准确获得活动流场模型分形特征参数值对提高模型的模拟预测精度具有重要意义。该研究采用染色示踪方法,将优先流流场从流动背景中显示出来,通过数字图像分析和采样分析获得优先流流场和流场内土壤含水率的分布模式,根据活动流场模型本构方程拟合活动流场模型分形特征参数值;针对3种常见的入渗后染色区内土壤含水率分布模式,分别提供了相应的活动流场模型分形特征参数的计算方法。研究结果显示,1）由于入渗后土壤水重分布的影响,活动流场区域和染色区域在整个入渗深度范围并不完全重合,因此仅可选择活动流场与染色区域相重合深度范围内受土壤初始含水率影响较小的数据来拟合活动流场模型分形特征参数值;2）土壤质地对入渗后染色区内土壤含水率的分布模式有显著影响,细质地土壤中入渗后染色区土壤含水率沿入渗方向逐渐减小,粗质地土壤中入渗后染色区土壤含水率沿入渗方向先增大后减小。     

果蔬气调保鲜运输车的设计与试验

为解决果蔬气调保鲜运输气调效率低且成本高等问题,该文提出了一种液氮充注气调保鲜运输技术,应用该技术制造的运输车主要由汽车底盘、基于压差原理的运输厢体、液氮充注气调装置、超声波加湿装置、制冷机组、变风量通风装置、换气装置和集中控制系统等组成。整车性能试验结果表明:在环境温度(33.5±1)℃、相对湿度59%±3%、采用仅中间留空堆栈、装载后厢体内后部温度(22.3±0.3)℃的条件下,物料初始温度为4.82和6.38℃时,调控至目标环境所用时间为52和90min;物料初始温度基本相同(4.65～4.82℃)、采用仅中间留空、中间与两侧留空和无空留堆栈方式时,调控至目标环境所用时间分别为52、30和77min,相对湿度自85%升至90%所用时间分别为26、9和33min,中间与两侧留空堆栈方式在调控速度方面依次优于仅中间留空和无空留堆栈;实载时厢体内氧气体积分数自20.9%降至5%用时28min,平均消耗液氮18.99kg,气调效率高且使用成本低。研究结果对提升果蔬气调保鲜运输技术水平具有一定参考价值。     

土壤溶质迁移的指数函数模型

边界层方法是描述土壤溶质迁移的简单方法,通过边界层距离与时间的关系可以估计溶质迁移参数。基于边界层方法,研究了土壤溶质迁移的数学模拟及相应参数估计问题。假定土壤溶质浓度剖面为指数函数,得到了描述溶质浓度分布的指数函数模型。各参数对边界层距离的影响分析表明,应选取较小的孔隙水流速度、短历时推求土壤溶质迁移参数;对不同模型预测土壤溶质分布进行比较,结果表明,在短距离处指数型解与精确解的误差比其它都要小。误差分析表明了指数函数模型的有效性和实用性。     

Influence of root restriction on two cultivars of summer squash (Cucurbita pepo L.)

Variable root restricting conditions were imposed on summer squash (Cucurbita pepo L.) cultivars ‘Senator’ and Dixie’ using container sizes of 0.35, 2.00, and 7.60 liters. Nondestructive and destructive plant sampling were conducted to evaluate leaf area production, dry weight accumulation and partitioning, crop growth rate and net assimilation rate, and flower and fruit development. Within 10 days after transplanting (DAT), ‘Senator’ exhibited declining leaf area production under increased root restriction, and within 17 DAT leaf area was diminished for both cultivars under increased root restricting conditions. Dry weight accumulation in leaves, stems, roots, and fruit was reduced for both cultivars over time and level of root restriction severity. There was a tendency for greater vegetative growth reductions with ‘Senator’ than with ‘Dixie’ at comparable levels of root restriction. Root‐to‐shoot ratio, timing and duration of flowering, and sex of flowers were not significantly impacted by root restriction level or cultivar. Fruit dry weight was greatest for Dixie’ early on, but by 28 DAT, total fruit dry weight produced did not differ for the cultivars except under the most severe root restricting conditions. Fruit dry weight production was limited for both cultivars as container volume became smaller.     

Analysis of amino acid uptake and translocation in Arabidopsis with a low‐cost hydroponic system

In soils, amino acids may be an important source of nitrogen for plants, at least in those where organic matter is not quickly degraded. The physiology of uptake of amino acids by roots was mainly studied in the 70's and 80's, before genes encoding amino acid importers were cloned in the 90's. While two families of amino acid transporters have been identified, yielding a total of about 100 genes, the role of each member is yet to be elucidated. As a tool for studying the role of amino acid transporters from Arabidopsis we set up a new hydroponic system suitable for radioisotope use. This system enables reproducible amino acid uptake by roots and estimation of the transport to the shoots of the amino acid taken up. We show that the rates of glutamine (Gln) uptake by wild‐type roots and transfer to the shoots were linear, and that other tested amino acids were translocated to the shoots with lower efficiency than Gln. A T‐DNA insertion mutant for a Gln exporter was compared to the wild‐type plants. Gln uptake and transfer were similar in both genotypes, showing that the suppression of the exporter did not affect uptake or transfer of amino acids to the shoots. The main advantage of the hydroponic system presented here is that all the materials used to grow Arabidopsis are virtually free and can therefore be discarded, a useful feature when working with radioactivity.     

基于无人机和卫星遥感影像的制种玉米田识别纹理特征尺度优选

制种玉米田在高空间分辨率遥感影像上呈现的明显条带状纹理,是有效区分光谱值相近的大田玉米和制种玉米的重要信息.该文在新疆维吾尔自治区奇台县玉米种植区以高空间分辨率的无人机遥感影像为数据源,针对制种玉米识别的纹理特征计算尺度问题,首先采用最近邻内插法对制种玉米和大田玉米样本田块的无人机影像进行重采样,得到不同分辨率的样本;然后用融合Uniform-LBP(local binary pattern)和GLCM(gray level co-occurrence matrix)方法得到提取玉米田块纹理特征合理GLCM参数,其中方向参数为0°、45°、90°和135°这4个方向上的纹理特征值的平均值、距离为5~7像元、灰度级为8;通过多尺度对比分析,得到最适宜区分制种玉米与大田玉米的纹理辨率为0.6~0.9m.最后采用奇台县的0.7m分辨率的Kompsat-3遥感影像进行验证,在多时相EVI(enhanced vegetation index)光谱信息识别玉米的基础上,利用本文确定的纹理分析方法,通过决策树建立规则识别制种玉米,识别精度达90.9%.通过该文的研究,可为高空间分辨率遥感制种玉米田监管提供支撑.     

基于无人机数码影像的冬小麦叶面积指数探测研究

叶面积指数(LAI)是评价作物长势的重要农学参数之一,利用遥感技术准确估测作物叶面积指数(LAI)对精准农业意义重大。目前,数码相机与无人机系统组成的高性价比遥感监测系统在农业研究中已取得一些成果,但利用无人机数码影像开展作物LAI估测研究还少有尝试。为论证利用无人机数码影像估测冬小麦LAI的可行性,本文以获取到的3个关键生育期(孕穗期、开花期和灌浆期)冬小麦无人机数码影像为数据源,利用数字图像转换原理构建出10种数字图像特征参数,并系统地分析了3个生育期内两个冬小麦品种在4种氮水平下的LAI与数字图像特征参数之间的关联性。结果表明,在LAI随生育期发生变化的同时,10种数字图像特征参数中R/(R+G+B)和本文提出的基于无人机数码影像红、绿、蓝通道DN值以及可见光大气阻抗植被指数(VARI)计算原理构建的数字图像特征参数UAV-based VARIRGB也有规律性变化,说明冬小麦的施氮差异不仅对LAI有影响,也对某些数字图像特征参数有一定影响;在不同条件(品种、氮营养水平以及生育期)下的数字图像特征参数与LAI的相关性分析中,R/(R+G+B)和UAV-based VARIRGB与LAI显著相关。进而,研究评价了R/(R+G+B)和UAV-based VARIRGB构建的LAI估测模型,最终确定UAV-based VARIRGB为估测冬小麦LAI的最佳参数指标。结果表明UAV-based VARIRGB指数模型估测的LAI与实测LAI拟合性较好(R2=0.71,RMSE=0.8,P0.01)。本研究证明将无人机数码影像应用于冬小麦LAI探测是可行的,这也为高性价比无人机遥感系统的精准农业应用增添了新成果和经验。     

无人机遥感解析田间作物表型信息研究进展

田间作物表型信息是揭示作物生长发育规律及其与环境关系的重要依据,传统的田间试验取样和车载高通量平台测定作物性状参数的方法耗时耗力,且空间覆盖不全,限制了作物科学研究的快速发展,而以无人机为代表的近地遥感高通量表型平台凭借机动灵活、成本低、空间覆盖广的优势成为获取田间作物表型信息的重要手段。该文根据国内外无人机遥感平台解析作物表型信息的最新研究成果,针对不同传感器类型分析了无人机遥感解析作物表型信息的应用及其不足,总结了遥感定量反演作物表型信息的方法体系,展望了无人机载遥感技术在作物表型信息解析方面的应用前景。该项研究成果对推广无人机遥感平台获取田间作物表型信息、提高复杂农田环境作物长势信息的解析和辨识能力具有重要意义。