苹果黄色叶螨(Eotetranychus Sp.)生物学特性的研究

苹果黄色叶螨是近年四川省三州苹果产区发生的一种害螨。该螨在雅安一年发生8～9代。以部分第8代和第9代雌成螨越冬。越冬雌成螨于次年3月上、中旬开始活动,以两性生殖及孤雌生殖繁殖后代。全年中越冬代历期长约5个多月,其余各代约1.5个月。各虫态历期因世代不同而异。各代雌螨寿命及产卵量,以越冬代及春、秋代寿命长,产卵量高。     

桃疏果套袋试验初报

1990-1991年,在四川省江油市对桃进行了疏果套袋试验研究。结果表明,通过疏果套袋,单株产量增加17.2斤,提高59.4％;亩产量增加358斤,提高43.3％;好果率增加52.7％,基本解决了“十桃九烂”问题;而且增强了果实着色,提高了果实整齐度,改善了品质。使每斤售价提高0.43元,每亩喷药投资降低8-10元,每亩净增产值683.46元。     

苹果苜蓿苔螨种群密度的零频率估计初探

本文用三种不同方法对苹果蓿苜苔螨种群密度进行了零频率估计,并对各种方法的估计精度作了比较,同时计算出对应不同抽样精度的理论抽样数表。结果表明,零频率估计苹果苜蓿苔螨的种群密度在实际调查中是可行的。其中以D.J.Grrard与H.C.Chiang方法的估计精度较高。     

Application of AHP-ATA in Elevator Risk Assessment

To analyze the safety of elevator system quantitatively, the risk factor weights aiming at the risk evaluation for elevator system are analyzed based on Analytic Hierarchy Process (AHP) in this paper. The Accident Tree Analysis (ATA) is also introduced to analyze accidents leading to the dangers during elevator running as the basis of weight assignment. The risk evaluation model of elevator system is built and its safety grade is set. The quantitative assessment for elevator system through linear weighted sum law is implemented. This method combining AHP and ATA in this paper avoids subjectivity and one-sidedness of weights indexes caused by expert-scoring method. This elevator system risk evaluation system provides feasible method of assessing safety grade subjectively.     

不同粗度苹果苗木与定植后生长结果关系的研究

1986—1989年在四川盐源果场对不同粗度的金冠、红星、富士苹果苗木定植后的生长结果情况进行了研究。结果表明:定植时的苗木粗度与定植后的树体生长量及单株产量有着密切的关系。培育1.5cm以上茎粗的苹果苗木有利于加速生长,早成形,早开花结果,提高早期产量。     

大叶黄杨炭疽病的病原初步研究

四川雅安的大叶黄杨炭疽病的病原菌Colletotrichun gloeos' porioides(Perz.)Sacc。在自然条件下和病叶保湿培养均不产生有性世代,但在PDA或C32N22平板上,条件适当时产生有性世代Glomerella cingulata。菌丝生长、分生孢了产生和萌发及附着胞形成都受温度、湿度、pH、光线等环境因素的影响。病菌在大叶黄杨的芽、叶、叶柄及茎的皮层中存在潜伏侵染。     

Secondary succession in the Mopani veld of the Limpopo Valley,South Africa

The long-term establishment sequences of the herbaceous and woody component of the Mopani veld of the Limpopo Valley were studied and documented. Based on vegetation surveys conducted at three enclosed sites at the Messina Experimental Farm during the period 1964 to 2001, no clear fixed grass species establishment sequence was observed. The classic plant succession model of the grass component, as usually found in other veld types, is absent in Mopani veld of the Limpopo Valley. Shallow, nutrient poor, gravelly, severely eroded soils with low moisture retention and a high runoff rate are mainly colonised by annual grasses and forbs. Perennial grasses take long to establish. This results in an unstable herbaceous component that is vulnerable to changes, which in turn depends on the erratic availability of soil moisture. Where the woody component is concerned, eight tree species appeared to be early colonisers, five intermediate colonisers and seven late colonisers. Tree numbers increased at sites with deeper soils, indicating that bush encroachment is a general, natural process that occurs irrespective of rest treatments applied to the herbaceous component. At a site with an extremely shallow soil, bush density decreased, suggesting that the bush encroachment process in the Limpopo Valley is much more affected by soil and climate than in other veld types and climatic zones of the Limpopo Province.     

水泥混凝土路面传力杆系统极限承载力的扩展有限元分析

针对超载引起的水泥混凝土路面传力杆系统的早期损坏问题,在多工况道路整体结构三维有限元分析的基础上,基于扩展有限元方法与子模型技术,对传力杆周围混凝土的承载力极限开裂过程进行了数值模拟。计算给出了传力杆周围混凝土材料内裂纹萌生、扩展及最终的破坏形式,并设计足尺试验对数值模拟结果进行验证,对比结果表明两者在加载点荷载-位移曲线与裂纹断裂模式上吻合较好。根据该文的研究可以发现,采用扩展有限元法与子模型技术相结合的方式,能够快速、准确地计算传力杆系统的极限承载力,进而反推出水泥混凝土路面缩缝结构的临界车辆轴载。同时该文的研究方法为解决混凝土结构局部应力集中区域的开裂、破坏过程行为研究提供了一种可行性数值研究手段。     

动态性状功能定位模型的优化

功能定位的实质是将动态性状变化过程的基本规律镶嵌在QTL定位框架内。拟合与时间相关的QTL基因型的期望均值向量和剩余误差的协方差矩阵是动态性状功能定位的核心内容。根据QTL的统计检测效率,通过比较关于QTL基因型的期望均值向量和剩余误差的协方差矩阵的子模型的不同组合,来筛选优化的功能定位模型。以水稻一个DH群体的叶龄性状为例,我们分别用3个具有生物学意义的子模型和2阶Legendre多项式去拟合QTL基因型的均方向量,用13个平稳和非平稳模型去描述剩余协方差的变化。其结果GM2和“衰减”指数模型组合被确定为用来检测水稻第3个连锁群控制叶龄动态变化QTL的优化模型。