高地隙施药机喷杆自动调平系统设计与试验

因田间地表起伏,高地隙施药机在作业过程中车体极易发生横滚方向的倾斜,同车体刚性连接的喷杆同时倾斜,甚至与作物、地面碰触,影响喷药均匀性和作业安全性.为此基于机电液一体化控制方法,设计了高地隙施药机喷杆自动调平系统.设计电控液压调平机构,使喷杆与车体柔性联接,实现在横滚方向上喷杆与车体的相对转动.采用姿态测量方法实时检测...     

离子束介导外源全DNA转化拟南芥菜的诱变效应

用 30kev的Ar+ 离子 ,以 1.5× 10 17ions/cm2 的注入剂量分别介导外源拟南芥菜 (Lansberg生态型 )、甘蓝、红甜菜和芦荟的全DNA转化拟南芥菜种子 (Columbia生态型 )。转化当代营养期表型变异率与外源供体和转化受体的亲缘远近没有必然的联系 ,而低育性株率却随着外源供体亲缘关系的从近到远 ,呈现一种从低到高再变低的变化趋势。从低育性株后代中选育出 2个稳定的突变体 ,该突变体不但保持了其亲本的低育性 ,而且其他性状也有较显著的变异 ,如株型、叶型等。     

木屋圆木梁加工中心转塔式主轴结构设计与研究

通过对圆木梁加工形式的分析,确定加工中心转塔式主轴结构的总体布局方案,利用SolidWorks软件对木屋圆木梁加工中心进行三维建模。完成了矩形转塔、车外圆和铣横向榫槽主轴总成、钻孔主轴总成、铣纵向榫槽主轴总成、铣端部榫槽主轴总成、转动总成的结构设计及单位切削力、切削功率等主参数的设计计算。该设计使加工中心能够一次性进行车削、铣削、钻孔等形式的加工,大大提高了木屋圆木梁的加工精度和加工效率。     

宜昌夷陵长江大桥正桥主梁悬拼施工技术

本文以宜昌夷陵长江大桥为例 ,介绍了大跨径斜拉桥悬拼施工工艺特点 ,通过控制预制主梁、运输、吊装悬拼 ,确保主体施工质量 ,同时也大大提高施工效率。     

现浇空心板在设计中的应用

作者依据工程实例，介绍了现浇空心板在设计中应遵循的基本原则及各种必要的构造措施。     

离子注入生物学在D110菌诱变育种中的应用研究初报

本研究采用离子注入生物学技术，进行了D110菌为出发菌的诱变选育高产谷氨酸菌种的试验研究。通过研究已经筛选到高产菌株D5221,，其产酸幅度比出发菌提高了35％，传代稳定性达到8代，10批次摇瓶发酵平均糖酸转化率可以达到43％，RG％（残糖）达到2％以下。该研究为进一步的梯次注入奠定了基础。     

Study on the Key Construction Techniques about the Prestressed Transform Beam of Chongqing People''s Mansion

In order to ensure the construction quality of the massive prestressed transform beam, to prevent and control the cracking before tensioning ,the technology of casting ,methods of temperature and crack controlling are carefully analysed and theoretical calculation is carried out as well as the temperature inspection during construction ,all of which have effective results. Some prestressed construction points of transform beam are also introduced in this article, and reference advices are given at last.     

Experimental Study on Flexural Behavior of Reinforced Concrete Beams Strengthened With Ferrocement Mortar

Experimental research on flexural behavior of the different grade RC beams strengthened with ferrocement mortar through six RC beams is carried out. The matching of original component concrete to the composite mortar strength rank is studied and its influence on bending strength, the crack-resisting capacity and the bending stiffness of RC beams is analyzed. Based on plane cross-section assumption and the experimental results, the formulas of the theoretical ultimate strength capacity and stiffness are brought forward. The calculated results fit well with the experimental results, to provide a theoretical reference for actual engineering designs.     

Effect of Varying Longitudinal Reinforcement Ratios on Shear Behavior of Reinforced Concrete Beams Without Web Reinforcement

Effect of varying longitudinal reinforcement ratios on shear behavior of reinforced concrete simply supported beams without web reinforcement was analyzed in this paper, with emphasis on both shear ultimate capacity and failure mode, on the basis of available testing data. Generic laws were thus obtained and codified methods, including ACI Code and China Design Code of Reinforced Concrete Structures, were evaluated as a result.     

电子束降解氯霉素调控因子试验

电子束降解氯霉素单体水溶液 ,其降解效果与处理条件有关。处理剂量高、单体浓度低和充氮 ,降解效率高 ;低温处理 ;充 0 5 %H2 O2 且pH调高 ,相对降解效率低