半粒稻米直链淀粉测定方法的研究及应用

本文提出一个简便易行的分析方法,用1粒稻米既可测出其中的直链淀粉含量,还可用以繁种,便于在育种早代选择优良个体、提高效率,加快进程。用本方法测得的直链淀粉含量与用中华人民共和国国标法GB_(7648-87),测得的结果经t检验,差异不显著。利用本法分析了F_1代种子及其亲本的直链淀粉含量,结果表明,在非糯品种与糯稻品种的两     

小麦品种对赤霉病抗扩展性的遗传研究

本研究采用单花针注法接种,以病小穗数为统计单位,对1个感病品种和6个抗病品种杂交取得的F_1、F_2、B_1、B_2及其P_1和P_2进行了抗性调查,研究了这6个小麦品种抗赤霉病性的遗传,结果表明:6个抗性亲本抗性由强到弱的顺序为繁60096、苏麦3号、宁7840、翻山小麦、龙79B-1165、克80F_(3-119),抗病性以加性效应为主,显性效应不可忽     

外源C_4作物DNA导入小麦的研究

利用小麦自交后的花粉管通道,将C_4作物玉米或高粱的DNA导入小麦的种胚细胞,结果受体后代发生了广泛的变异,而且受体不同,所发生的变异不同。甘麦8号受体后代植株变矮,结实率低,分蘖多至5个,少至完全不分蘖;8347—2-4和8013—3品系后代中出现不育株;6873—20—3品系受体后代的籽粒由红色转变为白色而且稳定遗传;蓝粒麦受体后     

PROBABILISTIC EVALUATION FOR STEEL FRAME COLUMNS OF TALL BUILDINGS

Based on properties of parameters and test data of dom-estic steel,this paper analyses the reliability and partial coefficient forresistance of steel frame columns of tall builings.The result may serveas a scientific basis.It is not only for domestic steel instead of importedsteel in building tall steel structures,but also for compiling concerendstandards.     

KINEMATIC ANALYSIS AND CALCULATION OF SLEWING MECHANISM ON HYDRAULIC EXCAVATOR DRIVEN BY VARIABLE DISPLACEMENT PUMPS WITH TOTAL CONSTANT-hp CONTROL

There are two main problems in the kinematic analysisof slewing mechanism on hydraulic excavator driven by variable displace-ment pumps with total hp-control when the excavator works and it'spumps get into variable displacement state as well.The first is how todetermine the oil flow in the hydraulic system according to the sum ofthe instantaneous pressure existing both in the slewing motor and in theworking cylinder.The second is how to calculate the driving torqueacting on the mechanism according to the instantaneous pressure existingin the motor.At pressent,the methods used for the kinematic analysisof the mechanism are based upon the assumption of the mechanism to bedriven by the fixed displacement pumps or by the variable displacementpumps with individual constant hp-control.But in these ways,theproblems mentioned above cannot be solved.This paper,on the basisof the variable displacement characteristic of the pumps with totalconstant hp-control,analyses the general kinematic pattern of the slewingmechanism in detail,presents the mathematical model and the numericalmethod used for it's kinematic analysis and establishes the the basis forevaluating it's design.     

EFFECT OF SEMI-RIGID CONNECTIONS ON BEHAVIOR OF STEEL FRAME

Modeling of girder in steel frame with semi-rigid conn-ections as partially restrained beam element is proposed for elastic-plasticanalysis of steel frames with semi-rigid connections.The results whichare obtained from analyses of elasticity,plasticity and stability for steelframes with semi-rigid connections have significant effects on structuralbehavior.It is necessary to consider the influences of semi-rigid conn-ections on the analysis and design for steel frames.     

植物群体遗传进化研究方法探析

[目的]评估植物群体遗传进化研究涉及的相关算法软件,为该研究领域提供方法选择参考.[方法]利用重测序数据,就群体遗传进化研究的各种算法做比较,对相关算法分析效果做对比评估.[结果]评估结果表明,进化树耗时和数据大小、模型选择均有较大关系,两者共同决定运算时间,另外运算效果还和多序列的比对效果有很大关系.群体结构分析fastStructure、Admixture软件运算速率、准确度较Structure软件有明显提高.主成分分析耗时相对较少,可用Cluster和R软件实现,两款软件的计算结果可相互验证;连锁不平衡分析推荐Plink2软件.[结论]算法及软件的选择对植物群体遗传进化研究的效率、结果影响较大.     

维生素对白僵菌生长和液生分生孢子形成的影响

对球孢白僵菌在不同维生素为生长辅助因子的液体培养基中菌丝生长和液生分生孢子的形成进行研究。结果表明,不同维生素对球孢白僵菌的生长及液生分生孢子的形成影响极显著。在培养液中添加适宜的维生素能有效地刺激液生分生孢子的形成,VB6+VB1+VB2或复合维生素B能使球孢白僵菌获得较高的液生分生孢子产量,产孢量分别高达5.03×1011个·L-1和5.12×1011个·L-1。同时试验还表明,液生分生孢子的产量与维生素组合有关,复杂的维生素组合比单一的维生素更有利于液生分生孢子的形成。     

基于校园网络的综合教务管理系统的设计与实现

建立基于校园网的综合教务管理系统是对现有教务管理模式的重大改进。介绍了该系统的网络结构方案、软件调试与设置、对用户的管理与授权及信息安全措施