水稻上三种条斑病细菌DNA的多态性初析

 试用40个引物对我国水稻条斑病菌、"稻短条斑病菌"和李氏禾条斑病菌等14个代表菌株进行RAPD分析,其中11个引物的扩增产物表现明显的多态性,共扩增出158条谱带,多态性为89.74%。聚类分析结果显示14个菌株可区分为3个类群,第1群包括LLS2、LLS3、LLS4、RS05、R1008、TAS和TAX;来自不同稻区水稻条斑病菌的群体结构差异明显,分属于第2群(如RS-Hai等)和第3群(如RS105等)。菌株DNA-RAPD指纹分析和致病性测定结果证明:李氏禾条斑病菌、"稻短条斑病菌"在水稻和李氏禾上不仅可相互侵染,而且遗传背景的相似性较高,确认是同一种病菌,其与小麦黑颖病菌亲缘关系较近,但与水稻细菌性条斑病菌具有明显差异。     

蛋氨酸锌的生物学功能及其在家禽生产中的应用

蛋氨酸锌是由蛋氨酸与无机锌在特定条件下发生配位形成的具有独特环状结构的金属螯合物,是一种类似动物体内吸收和发挥生物功能形式的新型有机微量元素添加剂。研究发现,与无机锌相比,蛋氨酸锌具有生物学效价高、毒副作用小、改善机体免疫力、增强抗应激能力等生物学功能,能显著提高家禽生产性能、改善蛋壳质量及减少家禽粪便中重金属排放量。本文对蛋氨酸锌的理化性质、吸收机制、生物学功能及其在家禽生产中的应用作一综述,以促进蛋氨酸锌在家禽生产领域的应用及其深入的研究。     

基于DNA遗传算法的大坝安全组合

大坝安全的组合优化监控模型实际上为一带约束的优化问题，将DNA遗传算法应用于大坝安全监控领域中，用罚函数法将有约束的优化问题转换为无约束的优化问题，建立了大坝安全监控的组合优化模型。实例计算表明，该方法是可行的，所建立的组合优化模型在拟合与预报精度上要优于单一的模型。     

液压脉动衰减器的动态品质

用集中参数法根据液压系统中流量脉动与压力脉动的关系提出了能够准确反映液压脉动衰减器动态品质的概念——液压脉动衰减函数,由此得出关于液压脉动衰减器的一般设计原则,据此对涡流型液压脉动衰减器进行了理论分析和实验研究。     

考虑非达西流情况下地下水向集水建筑物运动的非稳定理论的研究

在考虑到承压含水层完整井附近同时存在着非达西流区域和达西流区域、并假定非达西流区域的渗透规律可用Ｆｏｒｃｈｈｅｉｍｅｒ方程描述的基础上，通过求解非稳定渗流方程，得到了该情况下两个不同区域中的解析解，并且针对具体情况下的解析解及其物理意义进行了讨论。同时应用该理论，还得到当ｒ→∞或ｔ→∞时，相应于达西流区域的井函数趋于泰斯曲线，而对于非达西流区域，井函数曲线趋于泰斯曲线的条件是时间取较小值。     

Soil system and pedogenic processes: Self-organization, time scales, and environmental significance

The essence of pedogenesis, as a synergetic process, consists in generation, selection, accumulation and differentiation of the solids produced in the course of bio-abiotic processes functioning within a soil body. Soil formation in the broad sense is the result of synergetic processes of self-organization of an in situ soil system during its functioning in time and space. Soil formation, sensu stricto, is the transformation of the solid-phase lithomatrix (parent material) of the soil system into the pedomatrix (soil body, soil mantle). Pedogenesis is perceived as an integration of specific pedogenic processes (SPP); each of them characterized by a definite set of solid-phase pedogenic features. Each soil body is formed by a combination of some SPP. The whole set of SPP may be grouped in accordance with their essence, characteristic times (rates) and reversibility-irreversibility. In terms of characteristic times (rates) they may be arranged in three main groups: rapid (10^1–2 years), medium-rate (10^3–4 years), and slow (10^5–6 years). Soil system functioning and soil formation are intimately linked but fundamentally different processes: the former is infinite in time, if not interrupted by external factors; the latter, as any self-organization process, is finite in time and tends to reach a steady state. The theoretical grouping of the pedogenic processes according to their essence and self-termination or quasi-equilibrium is proposed. All the diagnostic soil horizons (as defined in WRB) are perceived as more or less stable and “mature” degrees of soil self-development. They may be separated into favorable and unfavorable with respect to their suitability for biota. Favorable conditions are generally common in 12 out of 39 diagnostic horizons and properties (32%). They are mainly influenced by biotic fluxes and cycles, which are comparable to, or exceed, abiotic fluxes and cycles in their strength and capacity. In this case, biota transforms and improves the environment rather than adapts to it. Unfavorable conditions are more common in 27 out of 39 diagnostic horizons and properties (68%). They are influenced by the mutual action both of biotic and abiotic fluxes and cycles. In this case, biota adapts to the environment rather than improves it.     

硒的营养功能及缺硒对毛皮动物的危害

综述了微量元素硒对动物的营养功能和毛皮动物3种类型缺Se症及其防治措施。     

人参皂甙的生物学效应研究进展

人参皂甙在免疫调节、诱导细胞凋亡、抗组织损伤、抗肿瘤、抗氧化、治疗糖尿病等方面具有特殊的作用,同时也将作为一种绿色饲料添加剂应用于动物生产。因此,对人参皂甙的生物学效应的研究有重要意义。