Φ508mm套管补接技术在导管架平台的应用

在南海海域的某导管架生产平台，生产已超过20年，出现了多口井次的Φ508mm套管腐蚀穿孔现象。其中一口井的Φ508mm套管出现了穿孔断裂，致使井口头下沉，采取注水泥塞临时弃井，从断裂处回收Φ508mm套管，使溢油风险得到了控制。小尺寸的套管补接技术已应用非常广泛，但Φ508mm套管补接在国内还没有应用先例。通过不断的技术验证，引进国外的大尺寸套管补接器并加以改进，成功地在该井实施了补接作业，使停产两年的油井恢复了生产。     

Uncovering Micro‐Practices and Pathways of Engagement That Scale Up Social‐Driven Collaborations: A Practice View of Power

This paper explores how large‐scale social‐driven collaborations might grow in scale and help promote political change. We present the results of a qualitative investigation of a complex platform where multiple and hybrid collaborations co‐exist and where civil society plays a central role. Based on a longitudinal comparative case study, we draw a processual model describing micro‐practices and pathways of engagement. We show that the emergence of these collaborations requires a new type of convener, one that is able to manage the interplay between the sharing/co‐creation of abundant resources and the coordinated decentralization of informal authority. Our study extends existing debates on the role of resources and authority, showing the complementarity between possession and practice perspectives of power. Finally, we identified synergies between collaboration and social movement literatures, particularly showing that large‐scale collaborations could be mobilized to refine social movement agendas and achieve more purposive collective action.     

大型央企融资影响因素分析

本文首先对某央企债券发行情况进行了分析。在此基础上,从发行环境、发行条件以及发行程序等几个方面,分析影响央企融资的因素。最后,给出了相关结论及建议。     

基于AHP法的大型医疗设备配置模糊评价模型构建

构建大型医疗设备配置的模糊综合评价指标体系,为大型医疗设备配置作出全面、系统的评价,为医院及相关卫生管理部门提供可靠的数据基础和决策依据。分析了在大型医疗设备配置评价中的各种影响因素,应用层次分析法,确定了每个评价指标的权重,构建了大型医疗设备配置的模糊综合评价模型。通过模拟应用,进行P设备配置评价,验证了模型应用的合理性与有效性。运用该模型建立大型医疗设备配置评价体系,对各种影响因素进行了合理反映,作为评价工具是可行的。大型医疗设备配置评价模型是一种实用、有效的方法,有较好的应用价值,但仍必须在改革实践中加以深化与发展。     

利用遗传算法构造QC-LDPC码

考虑到围长(girth)对低密度奇偶校验（LDPC）码的影响,提出了一种利用遗传算法构造大girth的准循环LDPC(QC-LDPC)码的新方法。该方法借助于计算机搜索,多次运用遗传算法,分步提高girth,在得到大girth 的同时,构造出具有准循环结构的LDPC码。分析发现,该构造方法的复杂度与码长成线性关系。仿真结果表明：在误码率(BER)为10-6时,新方法构造的QC-LDPC码比基于欧式几何构造方法、Gallager和Mackay构造法分别获得约0.15 dB、0.5 dB和0.2 dB的净编码增益(NCG),且因具有准循环结构更易于存储和硬件实现。     

大数据环境下高校图书馆转型建设研究

转型是大数据环境下高校图书馆发展的必然趋势,也是时代和社会发展对高校图书馆提出的基本要求,更是高校图书馆自身核心竞争力的不断完善.本文论述高校图书馆在大数据环境下服务与管理转型必要性的基础上,从高校图书馆资源建设理念模式创新、读者服务理念、读者管理创新模式构建、探索岗位设置创新思路、实现各类数字资源不断重组和优化、不断提高读者参与程度、不断提升区域共享程度、不断提高和完善高校图书馆员素质等阐述高校图书馆的服务转型,以期指导高校图书馆实践.     

The contagion externality of a superspreading event: The Sturgis Motorcycle Rally and COVID‐19

Large in‐person gatherings of travelers who do not socially distance are classified as the “highest risk” for COVID‐19 spread by the Centers for Disease Control and Prevention (CDC). From August 7–16, 2020, nearly 500,000 motorcycle enthusiasts converged on Sturgis, South Dakota for its annual rally in an environment without mask‐wearing requirements or other mitigating policies. This study is the first to explore this event's public health impacts. First, using anonymized cell phone data, we document that foot traffic at restaurants/bars, retail establishments, and entertainment venues rose substantially at event locations. Stay‐at‐home behavior among local residents fell. Second, using a synthetic control approach, we find that the COVID‐19 case rate increased substantially in Meade County and in the state of South Dakota in the month following the Rally. Finally, using a difference‐in‐differences model to assess nationwide spread, we find that following the Sturgis event, counties outside of South Dakota that contributed the highest inflows of rally attendees experienced a 6.4–12.5% increase in COVID‐19 cases relative to counties without inflows. Our findings highlight that local policy decisions assessing the tradeoff between local economic benefits and COVID‐19 health costs will not be socially optimal in the presence of large contagion externalities.     

大区域发展战略下西安统筹科技资源的路径选择

西安拥有丰富的科技资源,但这种科技优势却未能充分转化为经济优势,主要是因为存在着科技资源的"分隔"、"分离"、"分散"等三分问题。以西部大开发、关中—天水经济区建设、西咸新区建设、西安国际化大都市建设、丝绸之路经济带建设等为组成部分,提出并构建西安大区域发展战略。该战略的提出进一步理清了西安统筹科技资源面临的巨大机遇和必要性,为西安统筹科技资源提供了坚实的现实基础和强大的牵引力量。西安统筹科技资源需要根据大区域发展战略下的角色定位和功能定位,实现由要素驱动向创新驱动的转变,有效破解科技资源"三分"问题,只有这样,才能实现西安的跨越式发展。     

Surviving bear hugs: Firm capability,large partner alliances,and growth

In exploring the downsides of partnering with large firms, extant literature has typically focused on the external perspective and the alliance characteristics of small firms. We argue that jointly considering the internal dimension of firm capability together with the external perspective promises to yield a fuller understanding of the nature and consequences of a small firm's relationships with large partners. We analyze a longitudinal dataset on the alliance activities and growth of small, independent studios in the U.S. motion picture industry during 1990–2010. Our findings indicate that small firms that engage in higher levels of alliance activity with large partners, i.e., the major studios, realize lower growth benefits from their internal capability. Copyright © 2013 John Wiley & Sons, Ltd.     

浅析几种影响粮食加工装备质量的关键技术及相应对策

本文详细分析了影响粮食加工装备质量的几种关键技术：即可靠性设计技术、智能化控制技术、关键零部件使用寿命技术、制造技术、大型化技术.从分析中得出我国粮食装备技术的不足以及引起不足的原因,并提出相应对策,希望引起加工制造企业足够的重视,提高我国粮食加工装备的质量.