鸡IGF-Ⅰ基因单核苷酸多态性及其与屠体性状关系的研究

本研究采用PCR-RFLP技术,对438只黄羽矮小型肉鸡的胰岛素样生长因子-Ⅰ基因(IGF-Ⅰ)的5′端进行遗传多态性研究,发现该区域的PCR扩增产物经Hinf Ⅰ酶切后出现GG、GT和TT 3种基因型。经χ2检验,群体在该位点上处于Hardy-Weinberg平衡状态(P>0.05)。方差分析结果显示,性别对9个性状(活体重、屠体重、皮脂厚、半净膛、全净膛、胸肌重、腿肌重、腹脂重、腹脂率)有极显著影响(P<0.01),对肌间脂肪含量有显著影响(P<0.05)。家系效应在8个性状上(活体重、屠体重、半净膛、全净膛、胸肌重、腿肌重、腹脂重、腹脂率)达到极显著水平(P<0.01);而基因型效应只在腹脂率上达到显著水平(P<0.05),腹脂重没有达到显著水平(P=0.0669)。不同基因型的最小二乘均值间多重比较结果发现,TT型的腹脂重和腹脂率均显著低于GT型(P<0.05),而GG型和GT、TT型的差异不显著(P>0.05)。     

小麦茎尖丛生芽诱导及植株再生

为了筛选不受季节限制的小麦遗传转化受体,研究了3个小麦栽培品种在3种萌发培养基、4种诱导培养基、3种不同诱导时间和3种生根培养基下从茎尖直接诱导丛生芽的最佳条件和方法。结果表明,MB5基本培养基不添加任何激素最适于小麦成熟胚萌发;而在MB5培养基中添加1.0 mg/L TDZ 和 0.5 mg/L IBA,小麦茎尖丛生芽诱导率最高;单个茎尖形成丛生芽的数目,随诱导时间延长而增加,诱导时间以不超过30 d为宜;品种间的丛生芽诱导率及丛生芽形成数目没有差异;最佳生根培养基为1/2 MS 基本培养基添加1.0 mg/L IBA。由丛生芽诱导再生发育形成的植株开花结实正常。这些研究结果为建立基于小麦丛生芽的再生及遗传转化体系提供了方法。     

湖南省鸡蛔虫线粒体nad1基因部分序列的测定及分析

本研究旨在阐明鸡蛔虫湖南分离株线粒体烟酰胺腺嘌呤二核苷酸（NADH）脱氢酶亚单位1（nad1）基因部分序列（pnad1）遗传变异情况。利用聚合酶链式反应（PCR）扩增鸡蛔虫的pnad1,应用Clustal X 1.81程序对序列进行比对。结果显示,所获得的pnad1序列长度一致,为408 bp。由于鸡蛔虫pnad1序列种内相对保守,种间差异较大,故可作为种间遗传变异研究的标记,从而为鸡蛔虫的分类鉴定及进一步的分子流行病学调查奠定了基础。     

小麦多酚氧化酶研究进展

小麦面粉和面食品的色度是小麦磨粉品质和面食品的主要评价指标.。特别是面条、馒头、饺子、烙饼等中式食品对白度的要求相当高。.多酚氧化酶(PPO)与小麦面粉及其面食品在加工、贮藏中的褐变直接相关.。同时,多酚氧化酶种类的遗传变异和表达差异也决定小麦籽粒中的PPO总活性高低,从而直接或间接影响面粉的白度。笔者综述了近年来小麦多酚氧化酶生化机理、分布和分子生物学遗传分析以及与品质关系等方面的研究进展,并且根据多酚氧化酶的表达特性,讨论了小麦高白度新品种选育的策略。     

Research on Neural Network Applied in Heat Load Control of Heat Pump System

In recent years, lots of heat pump systems have been applied for district heating. In order to insure safe and efficient running of these systems, perfect load control methods are necessary. In this paper, the load matching problem between heat pump syst     

Study on Softening Constitutive Model of Malan Loess

In this paper, based on the uniaxial compression tests, consolidated undrained shear tests,consolidation drainage shear tests of Malan loess with different water contents, and based on understanding deeply of peculiar physico mechanical property of Malan     

Analysis on function of several types polysilicate aluminum ferric 

Polysilicate metal salt exhibits excellent flocculation ability. Polysilicate aluminum ferric(PSAF) was prepared through copolymerization by sulphates and chlorides of aluminum or iron with polysilicate acid. The optimal hydrolysis parameter of different PSAFs was determined. Differences in turbidity and flocculation function of four types of PSAFs were evaluated. Furthermore, differences in coagulation and phosphorus removal were analyzed and discussed.     

Stress wave effect in numerical simulation on rock breaking under high pressure water jet

The evolvement of rock damage struck by a high pressure water jet is characterized by nonlinear properties, thus making it a complicated dynamic problem. Based on a nonlinear finite element and elastic plasticity theory, a computational model was established. The dynamic load striking the rock by a high pressure water jet was simulated by the dynamic contact method. Furthermore, the propagation of a stress wave in the same rock was simulated at different impact velocities. The results show that the propagation velocity of a stress wave is proportional to the impact velocity of the high pressure water jet. The effects of a stress wave in sandstone and coal impacted by high pressure water jets of the same velocity were simulated.The effect of a stress wave in coal was stronger than in sandstone, while the region of propagation of stress wave in coal was smaller.     

A control strategy for braking energy distribution and regenerative braking in a 4WD hybrid electric vehicle

Based on the braking theory of conventional vehicles and high efficient energy recovery and security braking, a control strategy for braking energy distribution and regenerative braking of a 4WD hybrid electric vehicle was proposed. Considering limiting factors, such as motor and battery efficiency, a simulation model of a regenerative braking system was built and a simulation of typical braking conditions was conducted. The simulation result shows that the highest energy recycle ratio can reach 87.5%, 47.8％, and 28.6％ when z is 0.1, 0.3, and 0.5, respectively, at 30 km/h. The control strategy for braking energy distribution and regenerative braking can satisfy demand for vehicle braking and obtain high regenerative energy.     

X-ray diagnosis spectroscopy of laser produced plasma

A new crystal spectrometer with high spatial and spectral resolution was designed to measure very low emissive X ray spectra of laser produced plasma in the 0.5 nm to 0.8 nm range. Twin channels collocated perpendicularly with two different crystal materials and forms were utilized for simultaneous measurement of spectral and spatial resolution. The imaging plate was employed to obtain high spatial resolution with effective area of 30 mm×80 mm. The basic parameters of crystals were analyzed and the design parameters of the spectrometer are presented herein. The first experiment was carried out at the 20 J energy laser facility of Research Center of Laser Fusion, CAEP. X ray spectra were obtained from Al laser produced plasmas with a spectral resolution of 1 000 to 1 500 for the spherically bent mica crystal spectrometer and spatial resolutions of 1.73 mm to 6.88 mm for the flat PET crystal in the same condition. It is suggested that the device be used in high density plasma diagnostics of a single laser shot.