南海北部早第三纪流沙港组孢粉组合   总被引：1，自引：0，他引：1  

孙湘君  孔昭宸  李明兴  李彭 《中国科学院研究生院学报》1982,20(1):63-72

In the northern part of South China Sea, including Tonkin Gulf, Hainan lsland, Leizhon Peninsula and some basin of Guangdong  Province,  Paleogene  deposits  are composed of three formations: the Weizhon, the Liushagang and the Changliu forma- tions arranged in descending order.  The paper on the palynoflora of the Weizhon Formation (early and middle Oligocene) is in press[2].  This paper deals only with the palynoflora of the Liushagang Formation, with may be divided into four main stages:       The first stage is represented by Monocolpollenites tranquillus and Crassoretitri- letes sp., assigned to early Eocene The second stage is characterized by Salixipollenites, Momipites triletipollenites and Operculumpollis.  Its age is middle Eocene.  The third stage is dominated by some species of Quercoidites  and  Ulmipollenites  and  also characterized by the presence of Platycaryapollenites  and Prominangularia  dogying- ensis, This sporo-pollen assemblage suggests a late Eocene in age.  The fouth stage is marked by profusion of some alga of brockish water, such as Rugasphera corrugia, Granodiscus gronulatus and some pollen types  of  Liquidambarpollenites   minutus, Multiporopollenites puctatus and Tricolporopollenites minutus.  The age of the last stage is assigned to early oliocene.       In generaly, the palynoflora of the Liushagang Formation is quite different from that of the Weizhou Formation.  The main types of spores and pollen are common with those found in Europe and North America of the same age, while the Weizhou Formation has many elements common both in this region and Borneo.       During Eocene and early Oligocene this area was  of continental  phase with brackish basins. At the beginning the climate was rather moist and hot, but then itbecame moist and warmtemperate.  相似文献   

善治理论与我国政府危机管理能力建设     

孔凡宏  陈向阳 《科技广场》2007,(4):51-53

我国在危机管理方面积累了丰富的经验。但比照善治的标准,仍多少存在着合法性的流失、透明度的缺乏、责任性的缺失、法治性的缺位、回应性的迟缓、有效性的弱化等现象。只有通过改善政府危机形象以增强合法性、准确及时地公开危机信息以增强透明性、严格危机事件问责以增强责任性、健全危机管理法律及规范公务人员行为以增强法治性、完善机构设置规范职能配置以增强回应性、加强人员培训及社会组织培育以增强有效性等举措才能达致政府危机管理的应然状态,提高我国政府危机管理的能力。  相似文献   

How does collaboration affect researchers’ positions in co-authorship networks?     

Xiangjie Kong  Mengyi Mao  Huizhen Jiang  Shuo Yu  Liangtian Wan 《Journal of Informetrics》2019,13(3):887-900

Collaboration usually has a positive effect on researchers’ productivity: researchers have become increasingly collaborative, according to recent studies. Numerous studies have focused on enhancing research collaboration by recommendation technology and measuring the influence of researchers. However, few studies have investigated the effect of collaboration on the position of a researcher in the research social network. In this paper, we explore the relationships between collaboration and influence by social analytical methods, which are pertinent to analyzing the network structure and individual traits. We evaluate three aspects of the researchers’ influence: friendship paradox validation, social circle, and structure of a researcher's ego network. Furthermore, the ”six degrees of Bacon number” theory, generalized friendship paradox, and triadic closure theory are introduced to support our analysis. Experimental results show that collaboration can help researchers increase their influence to some extent.  相似文献   

Bivariate grid-connection speed control of hydraulic wind turbines     

Chao Ai  Wei Gao  Lijuan Chen  Jiawei Guo  Xiangdong Kong  Andrew Plummer 《Journal of The Franklin Institute》2021,358(1):296-320

The requirement for An electrical grid-connected wind turbine is that the synchronous generator speed is stable within a required speed range for the electrical grid. In this paper, a hydraulic wind turbine (HWT) system is considered, and the working principle and working conditions of the HWT are introduced. A novel speed control method is proposed in this paper, using both a proportional flow control valve and a variable displacement motor, which are adjusted in combination to control the speed of the HWT. By establishing a state space model of the HWT and solving the nonlinear system with a feedback linearization method, a bivariate tracking controller is constructed to realize accurate speed control under fluctuating wind speed and the load disturbance conditions. The effectiveness of the control method is verified by simulation, but experimental results highlight problems with the method. The theoretical controller is simplified to reduce sensitivity to measurement noise and modeling error. The control effect has been improved to some extent, but it is limited. Based on these results, combined with the sliding mode variable structure control method and the feedback linearization method to solve the problem of measurement noise and modeling error, and the effectiveness of the control law is finally verified experimentally. It lays a theoretical foundation for the practical application of HWT.  相似文献   

Networked control for linear systems with forward and backward channels in presence of data transmission delays,consecutive packet dropouts and disordering     

Yanliang Cui  Lanlan Xu 《Journal of The Franklin Institute》2021,358(8):4121-4140

  相似文献   

南京市高职院校乒乓球选项课现状调查及对策分析     

孔煜  蒋琴华  裴春燕  王钧铭 《安徽体育科技》2011,32(1):61-63

通过文献资料法、专家访谈法、调查问卷法、数理统计法、逻辑分析法,对南京市部分高职院校的乒乓球选项课开展情况进行了调查和研究,并提出建设性建议。  相似文献   

图书馆特色建设探讨   总被引：2，自引：0，他引：2  

孔德超 《图书馆建设》2011,(1):95-97

图书馆特色是指图书馆在长期办馆过程中积淀成的比较持久稳定的发展方式和被社会公认的优良的管理理念、服务方式、资源及文化建设等方面特征的总和。图书馆应通过科学准确定位,创新办馆理念,建设特色鲜明的馆藏,延揽卓尔不群的馆员,营造完美、高尚的文化氛围及提供优质多样的服务6个建设路径来完成特色化建设。  相似文献   

Web数据关联创建策略研究   总被引：1，自引：0，他引：1  

邓兰兰  李春旺 《现代图书情报技术》2011,(5):1-6

调研关联数据的关联关系创建算法和策略,分析同构模式下属性相似度和图形相似度算法以及相应的组合策略,对比研究异构模式下包含和不包含实例信息的架构映射方法,对可创建丰富语义关联的推导传递的思想进行剖析,并提出关联创建面临的挑战。  相似文献   

数字典藏在E-learning中的应用     

郭韫丽  孔令保  李冬梅  吴先福 《图书馆学研究》2011,(2):27-29,42

数字典藏平台可以成为一个非常丰富与完整的数字学习环境,所具有的典藏功能、展示功能、教育功能和研究功能有助于营造一个好的E-learning环境。数字典藏应用于E-learning是数字典藏再利用一个可行的发展方向,有助于提高数字典藏资源的价值。  相似文献   

面向供应链融资的企业无风险收益合约研究   总被引：1，自引：0，他引：1       下载免费PDF全文

白少布  刘洪  孔锦 《科研管理》2011,32(3):137-144

摘要：供应链融资服务是一种新型的银行金融产品服务,是实现中小企业资金市场化的有效切入点。本文根据供应链融资运作中企业间的合作关系,建立了不同主体无风险合约模型。基于此模型,研究了银行和企业对贷款额度与利率的承受范围,分析了供应链融资参与主体间的无风险合约达成条件,提出了企业努力水平与贷款利率、贷款额度之间的激励关系。研究表明,供应链项目未来收益作为银行还款来源不仅与项目自然状态有关,还有与成员企业努力水平有着直接的关系,只有成员企业共同努力,才能保证供应链整体效益最大化,从而才能实现企业自身收益最大化。  相似文献