107杨不同插穗的育苗试验

正黑杨派无性系在世界发达国家的杨木生产中占有重要经济地位,特别是欧美杨无性系具有较强的杂种优势,表现出早期速生、无性繁殖容易、适应性强等特点,适宜于无性系育种。经长期引种实践和栽植历史证明,其适生于我国大部分平原地区,成为     

Long-term survival of dogs after cholecystoenterostomy: a retrospective study of 15 cases (1981-2005)

Fifteen dogs with extrahepatic biliary tract disease underwent cholecystoenterostomy. Long-term survivors were significantly older at presentation (mean age 140.5 months) than dogs that survived the first 20 days after surgery but subsequently died from causes related to the surgery or hepatobiliary disease (mean age 72 months). Dogs that died during the first 20 days had significantly more complications in the hospital than dogs that survived this period. The type of underlying hepatobiliary disease (i.e., benign or malignant) was not associated with either short-term outcome or long-term survival. Eight dogs died from causes related to surgery or hepatobiliary disease. Long-term complications included hepatic abscesses, acquired portosystemic shunts, pancreatitis, and vomiting.     

大白菜干烧心病发生和防治的研究

大白菜干烧心病是缺钙性生理病害,自1970年以来在我国北方大白菜产区危害日趋严重.此项研究的重点是从“心叶补钙”入手探索经济有效的防治方法.从结球始期应用0.7%有水氯化钙附加50ppm萘乙酸进行“心叶补钙”.经8年连续试验,防治效果可达80%以上.采用常规分析和~(45)Ca示踪试验的方法,证实了萘乙酸对钙素的吸收和运转有明显的促进作用,为改进大白菜干烧心病的防治方法提供了理论依据.     

热处理降低哈密瓜果实活性氧代谢减轻冷害

为探讨热处理能否激发哈密瓜果实抗冷性,减轻冷害。该文以"西州密25号"哈密瓜为原料,在已有研究的基础上,将哈密瓜在55℃热水中浸泡3 min,以室温(22±2)℃清水浸泡3 min为对照,待其表面水分完全晾干以后,放置于3~5℃机械冷库中贮藏,测定贮藏期间哈密瓜品质及生理指标。结果表明,与对照相比,热处理诱导哈密瓜果肉过氧化氢H_2O_2和超氧阴离子O_2~-含量短暂增加,但明显减少贮藏中后期(14~35 d)H_2O_2,O_2~-的积累(P0.05),提高活性氧清除酶过氧化物酶和超氧化物歧化酶的活性(P0.05),抑制细胞膜相对渗透率和丙二醛含量上升,降低贮藏后期的冷害发生率(P0.05),缓解果实可溶性固形物和抗坏血酸含量下降(P0.05),保持果实较好的品质。热处理主要通过诱导活性氧信号分子,提高活性氧清除酶活性、减少膜脂过氧化作用,从而减轻果实的冷害。研究结果为哈密瓜采后贮藏技术提供理论参考。     

黑龙江省农业机械化作业水平预测方法

黑龙江省农机化作业水平的预测是一个复杂的非线性系统,其发展变化具有增长性和波动性,对于拟合的方法要求较高。该文对黑龙江省农机化作业水平预测方法进行研究,在传统预测模型灰色GM(1,1)模型、平滑预测模型和回归预测模型的基础上建立了基础预测模型,并与BP神经网络模型组合,建立了灰色神经网络、平滑回归神经网络等组合预测模型,并预测了黑龙江省2008～2015年的农机化耕、种、收、植保、灌溉作业水平。结果表明,新的预测方法拟合精度高、有效、可行,为农机化作业水平的预测提供了一条新的途径;黑龙江省机耕、机播、植保作业水平很高,但是机收作业水平不高,机械化灌溉是主要的瓶颈,需要进一步发展。     

Detecting System of the Dielectric Loss in Capacitive Equipment Based on Virtual Instruments

A digital detecting system of the dielectric loss in the capacitive equipment is introduced based on virtual instruments.This system can real-time collect,analyze,process and storage electrical signals with National Instruments' program LabVIEW and ADLINK,s DAQ board.Through the simulation test in lab and the real test in electric substation,it is shown that this system has high accuracy on testing the dielectric loss in the capacitive equipment,the real test data is stable and the relative error of real dielectric loss is less than 5%.It is to say that this system can meet the requirement of the real on-line monitoring.     

Simulation Propagation of Partial Discharge UHF Signals in Transformer

Many factors affect the propagation of ultra high frequency(UHF) signals caused by partial discharge(PD) on the waveforms and energy of signals in transformer.To investigate the relationshi Pof factors and UHF signals,simulation model of transformer for PD study are established.UHF signals in simulation model of transformer caused by PD are calculated using finite difference time domain method.By means of amplitude and cumulative energy plot of simulation signals,and combing the measured result,the following factors:distance between PD source and detection position,different metallic conductor position around detection position and iron core and winding are researched,which contribute to comprehend the propagation characteristic of UHF signals and detect UHF signals accurately.     

牵引式方捆捡拾车原理研究

介绍了一种牵引式方捆捡拾车,该捡拾车可一次完成草捆的捡拾、装载和码垛等多项工序,极大地提高了工作效率。阐述了牵引式方捆捡拾车的基本结构,并研究了液压系统、操作机构的工作原理,为以后草捆捡拾车的研制及改进提供技术支撑。      

基于距离反比法的土壤盐分三维空间插值研究

以新疆兵团一块面积约70 hm2的盐碱地为研究对象,采用EM38与土钻取样相结合的方法得到了126个点不同土层(0~200 cm)的1 386个土壤盐分数据,应用三维距离反比法(3D-IDW)对土壤盐分进行了空间插值,探讨了垂向坐标扩大倍数和搜索点数对插值结果精度的影响。结果表明,研究区0~140 cm土层盐分平均含量较高,为1.84~2.11 g/kg,盐分变异较大,而140~200 cm土层盐分平均含量较低,为1.74~1.79 g/kg。所有土层盐分含量的统计特征值(平均值、标准差和变异系数等)均随土层加深而呈现递减的趋势。土壤盐分实测值和估计值的均方根误差随垂向坐标扩大倍数的增大而减小,随搜索点数的增加而增大,其值在0.1~0.4 g/kg范围内变化,当垂向坐标扩大300倍、搜索点数为6个时,插值效果较优。采用确定的参数对研究区的土壤盐分进行了三维空间插值,结果表明土壤盐分空间分布特征与实测值比较吻合,大部分区域土壤盐分含量小于2.5 g/kg,靠近北部和南部边界区土壤含盐量较低,属于非盐化土区,而大于4 g/kg盐化土主要分布在中间和南部局部区域。研究区80%土壤为非盐化土和轻度盐化土,20%为中度和重度盐化土。影响该区盐化土分布的主要因素有灌溉、局部地形、粘土层位置、地下水埋深和矿化度。当不同方向的取样间距相差很大时,选取合适的垂向坐标扩大倍数和搜索点数对保障3D-IDW法的插值结果精度至关重要。     

基于ARM9的嵌入式奶牛识别自动挤奶控制器

针对大型奶牛场传统人工作业方式费时费力、操作环节不够科学等问题,提出了基于ARM9的奶牛挤奶管理控制系统,应用于奶牛挤奶.依照科学的方法对奶牛进行自动挤奶,将挤奶环节对奶源地污染降到最低,准确地记录奶牛产量信息,便于牛场对奶牛的管理.采用ARM9系列芯片S3C2440作为系统的主控制芯片,Linux作为操作系统的内核,构建系统的软硬件平台.采用C语言编程,将识别的标签信息以及奶牛的产量信息通过串口传送到上位机.上位机采用SQL Sever2000作为后台数据库,C#为前台开发工具,开发客户机/服务器类型的应用程序.