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91.
职务发明专利授权意味着企事业单位或机关团体作为专利权人取得其雇员所发明技术的专利权。职务发明专利授权量可反映一个国家企事业单位或机关团体在其发明专利申请受理国运用专利制度获取技术竞争力的水平。根据世界知识产权组织的《国际专利分类号与技术领域对照表》,对我国1986—2006年发明专利授权按技术领域进行分类统计;从静态和动态比较的角度,对我国国内和国外发明专利授权格局及其演变进行分析;并对上述分析结果的公共政策含义进行探讨。  相似文献   
92.
Building on recent European studies, we used the Survey of Income and Program Participation to provide the first analysis of fertility differences between groups of US college graduates by their undergraduate field of study. We used multilevel event-history models to investigate possible institutional and selection mechanisms linking field of study to delayed fertility and childlessness. The results are consistent with those found for Europe in showing an overall difference of 10 percentage points between levels of childlessness across fields, with the lowest levels occurring for women in health and education, intermediate levels for women in science and technology, and the highest levels for women in arts and social sciences. The mediating roles of the following field characteristics were assessed: motherhood employment penalties; percentage of men; family attitudes; and marriage patterns. Childlessness was higher among women in fields with a moderate representation of men, less traditional family attitudes, and late age at first marriage.  相似文献   
93.
94.
Recent rapid economic growth in Ireland has been accompanied by a strong surge in the number of women in employment, and this has led to a significant increase in the proportion of dual‐earner families. These changes have brought the issue of reconciliation between work and care commitments to the fore. Flexible working arrangements in firms have been identified as one important means of balancing work and other commitments. In this article we investigate the relationship between four flexible working arrangements; flexitime, part‐time hours, working from home and job sharing, and two key employee outcomes; work pressure and work–life conflict, using data from the first national survey of employees in Ireland in 2003. Our results show that while part‐time work and flexitime tend to reduce work pressure and work–life conflict, working from home is associated with greater levels of both work pressure and work–life conflict. We conclude that it is important to distinguish between flexible working arrangements to discover their potential for reducing work pressure and work–life conflict.  相似文献   
95.
Criteria to protect aquatic life are intended to protect diverse ecosystems, but in practice are usually developed from compilations of single‐species toxicity tests using standard test organisms that were tested in laboratory environments. Species sensitivity distributions (SSDs) developed from these compilations are extrapolated to set aquatic ecosystem criteria. The protectiveness of the approach was critically reviewed with a chronic SSD for cadmium comprising 27 species within 21 genera. Within the data set, one genus had lower cadmium effects concentrations than the SSD fifth percentile‐based criterion, so in theory this genus, the amphipod Hyalella, could be lost or at least allowed some level of harm by this criteria approach. However, population matrix modeling projected only slightly increased extinction risks for a temperate Hyalella population under scenarios similar to the SSD fifth percentile criterion. The criterion value was further compared to cadmium effects concentrations in ecosystem experiments and field studies. Generally, few adverse effects were inferred from ecosystem experiments at concentrations less than the SSD fifth percentile criterion. Exceptions were behavioral impairments in simplified food web studies. No adverse effects were apparent in field studies under conditions that seldom exceeded the criterion. At concentrations greater than the SSD fifth percentile, the magnitudes of adverse effects in the field studies were roughly proportional to the laboratory‐based fraction of species with adverse effects in the SSD. Overall, the modeling and field validation comparisons of the chronic criterion values generally supported the relevance and protectiveness of the SSD fifth percentile approach with cadmium.  相似文献   
96.
关于十字军的反犹动机问题,学界观点纷呈。在各种观点中,基督教的反犹主义意识是主导因素,它推动了长达百年的反犹活动持续发生,而当时狂热浓厚的宗教氛围则为反犹暴行提供了合适"土壤",商品经济所带来的巨大压力则成为了反犹的突破口。诸多因素综合作用遂导致反犹活动频繁上演。  相似文献   
97.
针对纸机日益高速化、大型化的发展趋势,设计了国内先进的全数字化通信网络传动控制系统。系统采用西门子全集成自动化解决方案,实现造纸生产过程的全线集成控制。高可靠的工业现场总线PROFIBUS—DP和工业以太网相结合的网络结构,有效地实现了数据共享,全面解决了整个工艺过程的控制。文章详细介绍了控制系统的配置和功能,重点阐述了速度链、负荷分配控制、张力控制等主要控制原理。  相似文献   
98.
砂岩储层酸化的常规土酸体系存在与矿物反应速度快、酸化液的有效距离短和容易产生二次沉淀等问题。现存的缓速酸酸液体系不能克服粘土和石英界面反应速率的巨大反差,新的深度酸化工艺可以在一定程度上增加酸液的穿透距离,但工艺繁琐,且仍然不能解决沉淀、堵塞问题。多氢酸体系与现存的HF酸体系相比,其反应速度慢,溶解能力强,且具有良好的防垢性能和分散性能,可以抑制井眼附近的地层伤害,有效控制二次沉淀等优点。本研究对多氢酸的酸度特性、溶蚀性能、润湿性、静态腐蚀性以及多氢酸的分散和防垢性能进行了室内测试,并对土酸、氟硼酸及多氢酸进行了酸化效果实验评价。室内实验及现场应用表明,多氢酸性能优越,可明显提高酸化效果。  相似文献   
99.
The assessment of the degree of genetic variation in a natural population, and the nature of that variation, is of central importance in both theoretical and applied population studies. Two “variance” results in population genetics theory are presented. For the first, expressions are found for the expected difference in the estimates of genetic variation in a population obtained by two investigators sampling from the same population in the same generation. The second result concerns the question of whether the degree of genetic variation in a population is best estimated by using the number of alleles observed in a sample of genes or by the number of polymorphic sites observed in the sample. For some combinations of the actual degree of variation and the sample size the former is preferred while for other combinations the latter is preferred. The reason for this is discussed.  相似文献   
100.
从聚合物/表面活性剂二元体系的特点出发,综述了聚/表聚/表二元复合体系的实验室研究现状以及在胜利油田孤东七区54-61进行的矿场试验情况。聚/表二元复合驱是在聚/表/碱三元复合驱的基础上去掉碱所形成的低浓度的驱油体系,可以最大限度地发挥聚合物的粘度和弹性,减少乳化液处理带来的负面影响,减弱由于碱的存在引起的地层以及井筒结垢的现象。通过国内外研究结果分析表明,聚/表二元复合体系提高原油采收率幅度在20%左右;矿场试验取得了较好的效果。聚/表二元复合体系可以克服三元体系的缺点,作为一项新的驱油方法具有宽阔的发展空间。  相似文献   
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