H-Y antigen expression in heterogametic males (XY) and females (ZW): a factor in reproductive strategy?

The cells of heterogametic females with ZW sex chromosomes express H-Y or H-W antigen. A hypothesis is formulated to explain why these animals are capable of 'practicing' amphigonia retardata, i.e., delay in actual fertilization of eggs by retaining viable sperm within the oviduct for a considerable time (several months).     

软件系统设计中的模块化思想和技术

本文回顾了设计大型数据处理系统中广泛应用的结构化设计(SD)方法、结构化分析(SA)及结构化程序设计(SP),阐明控制问题复杂性的抽象和分解思想、模块特性、划分模块的原则和评价模块质量标准及模块独立性概念。     

钟表厂生产与货仓动态管理系统

介绍钟表厂生产与货仓动态管理系统的研制及其设计技巧。     

Reproductive consequences of mega vitamin E supplements in female rats

Summary Female rats fed 0, 25, 2500 and 10,000 IU vitamin E/kg diet for 3 months were examined for reproductive performance. On 10,000 IU vitamin E/kg diet, the fertility of inseminated rats was significantly reduced as compared to rats given normal or nutritional levels of vitamin E.This work was supported by research grants from the National Research Council of Canada and the Research Committee of The University of British Columbia. We thank Mrs Virginia Green for her help in statistical analysis. Reprint requests should be addressed to Dr I. D. Desai, Professor of Nutrition.     

龙头锰矿缓倾斜多层邻近薄矿体采矿方法试验研究

本文根据龙头锰矿试验矿块的地质条件和试采一年多以来的实测数据,以及室内相似材料模拟试验结果,分析研究缓倾斜多层邻近薄矿体的开采方法。研究表明,矿层群的开采,特别是近距、低品位矿层群的开采,多以分采为宜;只要合理选择凿岩爆破参数,和采取正确的台阶形式,能安全回采多层矿体而又不破坏厚度仅为2.7～2.9米的隔层。     

Reliability Analysis of Some Typical Repairable Systems with Arbitrary Repair-Time Distribution

In this paper, reliability of some typical non-Markov repairable systems, including series systems, m-out-of- n or majority vote systems, and n : m cross-strapping standby redundant systems with general repair-time distribution, are studied by applying the generalized Markov renewal process (GMRP). The stochastic behavior of the typical systems is analyzed here. Formulas for mean time to first system failure, MTBF, MTTR, and availability are then developed.     

应用单板机实现电机串级调速

本文介绍串级调节的基本原理。介绍用TP801—Z80单板机对电流速度双闭环交流调速系统进行直接控制。它具有调速系统的良好动特性和静持性,本系统适合调速范围较大的场所。它对节约能源将有重大的意义。     

用AHP方法分析砼碳化评价指标的权重

砼的碳化是一个受多种因素制约的复杂过程.要对砼碳化的现状作出评价,如何确定各影响因素的影响程度是其中的关键.本文应用AHP方法对这个问题进行了分析研究,确定了砼碳化现状评价指标的权重.     

湖南禾本科植物新分类群

作者于1987年在益阳林科所竹园和龙山县新发现禾本科植物的一个新种,三个新变种和一个新变型。这些植物的发现,不仅为世界植物分类研究提供了新的资料,而且这些新资源都很有利用价值。