非洲猪瘟疫情防控难点与对策

目前肉制品的健康情况备受人们关注,而猪肉是人们餐桌上必不可少的肉制品之一,猪只的安全饲养对人类的生命健康有重要的影响。在饲养猪只中,可发生多种传染病,其中最主要的一种是非洲猪瘟,该传染病不仅具有高热性的特点,还具有高度接触性的特点,再加上目前对于该种疾病还没有特效的疫苗,以及有效的治疗措施,因此,做好该种疾病的预防工作至关重要。该文主要论述非洲猪瘟进行论述,并制定相应的防控措施。为减少猪只发病几率奠定良好的基础。     

3D打印技术在水利水电工程施工中应用研究

对3D打印技术进行应用研究,阐述其精度、强度和速度等关键性能指标合理性,能够有效避免特殊形式结构部位的施工带来的成本、工期及质量问题,增加工程效益,并对溢流堰面特殊部位计算表面曲线轮廓,进行实验3D打印,最后总结3D打印在水利水电工程施工中的优势。     

液压升降折叠宽幅喷杆喷架的结构设计

针对目前植保机械中所使用的喷杆喷架稳定性差、折叠伸展需要人工辅助等问题,设计出了一种液压升降折叠宽幅喷杆喷架。对喷杆喷架的升降装置、90°液压油缸折叠机构、180°液压油缸折叠机构和整体宽幅喷架进行了理论分析和结构设计,并建立了关键部件的三维模型。通过田间试验验证了该装置设计方案的合理性,为研发先进适用、具有自主知识产权的液压升降折叠宽幅喷杆喷架奠定了基础。     

宽幅高效离心式双圆盘撒肥机设计与试验

为解决现有水旱田撒肥机械作业效率低、撒肥量调节技术落后、施肥均匀性稳定性差等实际问题,设计了一种同轴驱动的离心式双圆盘撒肥机。介绍了整机结构与工作参数,研究设计了撒肥传动系统、撒肥盘结构、排肥量液压调节装置等,并确定了关键结构和参数,同时进行了试验研究。试验结果显示,推肥板推肥角度-20°~30°可调,撒肥幅宽达到50m,总排肥量稳定性变异系数低于6%,施肥均匀性变异系数低于16%。研究结果表明,撒肥机工作性能稳定、撒肥量可控、抛撒均匀,整机设计满足水旱田宽幅高效撒肥作业要求。     

抗青枯病樱桃番茄品种的初步筛选及评价

对28个樱桃番茄品种的田间抗病性、植株类型、单果质量、果色、可溶性固形物含量等主要经济性状进行调查。试验结果表明,感病品种红艳发病最重,发病率为73.67%,其次是红箭、红日和金艳,发病率分别为23.33%、21.67%和20.33%,其他品种发病率都在20%以下;28个品种的果实颜色、大小、口感等差异明显,除黑宝石映泰及黄金蛋可溶性固形物含量在4.10%以下外,其他品种可溶性固形物含量都达5.20%以上。综合分析,筛选出绿天使、粉仙、红娘9号、绿圆、格丽贝、红椭圆等11个抗青枯病且经济性状优良的樱桃番茄品种,为优质抗青枯病樱桃番茄的选育和推广提供了参考。     

三道湾水电站正常溢洪洞及泄洪排

试验表明，三道湾水电站原设计存在以下问题：泄洪排沙洞单独全开运行工况下，其进口上方存在贯通性吸气漏斗漩涡；正常溢洪洞进口侧收缩十分严重，泄流量不足，闸后存在水翅、折冲波等不良流态，下游消能效果不佳；针对实际情况，试验通过在泄洪排沙洞进口增设消涡格栅，在正常溢洪洞进口设置椭圆形导墙、延长闸后收缩段，下游采用扩散挑流消能等措施，很好地解决了上述问题。     

Nonlinear Characteristic Modeling of Servo Value on Hydraulic Bending Roll System''s Dynamic Characteristic

Nonlinear characteristic of servo value is the important factor influencing hydraulic system, the model of electro-hydraulic servo pressure control system is designed. In this model, flux-equation of servo valve is specially applied and some non-linear characteristics are considered. Furthermore, SIMULINK toolbox of MATLAB language software is applied to solve mathematic model and simulation curves of some variables are obtained. The calculation results are in good agreement with the experimental results.     

Analysis of Radial Forces on the Seal Block in a Compound Gear Pump with 3 Idle Gears

By analyzing the pressure distribution between gears and sealing blocks in compound gear pump with three idlers,the resultant hydraulic forces acting on seal blocks are obtained.The conclusion is the unbalanced resultant hydraulic forces are relatively small in magnitude.In the pump,the inner sealing edges are long and so it s Sealing effect is good,but the outer sealing effect is relatively poor because of its short sealing edges.The little unbalanced force pushes the sealing block to te pumping chamber,therefore it is advantageous to meliorating the pump's sealing effect,thereby to improving it's volumetric efficiency as well.     

DYNAMIC ANALYSIS OF SPINDLE

In this paper, taking a D1201 spindle as an example, we discuss the dynamic analysis of spindle by using the theory of the complex model, we also analyse the factors which effect the dynamic characterics of spindle and give results which arc reference value to improving the structure of spindle,