检索结果-南通市图书馆

Secure Multi-keyword Search Supporting Dynamic Update and Ranked Retrieval

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China Communications 2016年第10期13卷 209-221页

作者： jingbo yan Yuqing Zhang Xuefeng Liu State Key Laboratory of Integrated Services Networks Xidian University National Computer Network Intrusion Protection Center University of Chinese Academy of Sciences

As cloud computing is becoming prevalent, data owners are motivated to delegate complex data managements to the commercial cloud for economic savings. Sensitive data is usually encrypted before being uploaded to the cloud, which unfortunately makes the frequently-used search function a challenging problem. In this paper, we present a new multi-keyword dynamic search scheme with result ranking to make search over encrypted data more secure and practical. In the scheme, we employ a powerful function-hiding inner product encryption to enhance the security by preventing the leakage of search pattern. For the concern of efficiency, we adopt a tree-based index structure to facilitate the searching process and updating operations. A comprehensive security analysis is provided and experiments over the real world data show that our scheme is efficient.

关键词： secure search ranked search dynamic update cloud computing

Enhancement of Thermo-Flow Performances by Windbreakers for Two-Tower Indirect Dry Cooling System

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Journal of Thermal Science 2020年第3期29卷 676-686页

作者： yan jingbo WANG Weijia CHEN Lei yanG Lijun DU Xiaoze School of Energy Power and Mechanical Engineering North China Electric Power UniversityBejjing 102206China

The winds will greatly weaken the cooling performance of indirect dry cooling system with twin *** exterior windbreakers are recommended to restrain the wind adverse effects in this *** macro heat exchanger model was adopted to simulate the heat exchange between circulating water and ambient *** performances of natural draft dry cooling system(NDDCS)with and without exterior windbreakers were numerically *** pressure,velocity and temperature distribution of cooling air in wind angles of 0°,45°and 90°was obtained and *** results show that in all wind directions,the performances for lateral sector of towers with windbreakers are significantly improved,but the low-pressure zone appears unexpectedly for the rear sectors,which reduces the air flow *** cooling performances of the twin towers with or without windbreakers decrease at first but then recover with the wind velocity ***,the optimal flow and heat transfer performances appear in the wind angle of 0°.The cooling performances can be significantly improved in all three wind directions due to windbreaker configuration.

关键词： indirect dry cooling system twin towers windbreakers wind directions flow and heat transfer performances

Effect of heat treatment on the microstructure of a Ni–Fe based superalloy for advanced ultra-supercritical power plant applications

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Progress in Natural Science:Materials International 2016年第2期26卷 204-209页

作者： Xinbao Zhao Yingying Dang Hongfei Yin Jintao Lu Yong Yuan Zhen yang jingbo yan Yuefeng Gu Xi'an Thermal Power Research Institute Co. Ltd. National Energy R&D Center of Clean and High-Efficiency Fossil-Fired Power Generation Technology

The effect of heat treatment on the microstructure and microhardness of a Ni–Fe based superalloy for700 °C advanced ultra-supercritical coalfi red power plants was investigated. Results showed that the main phases in the alloy were γ, γ′, MC and M23C6, and no harmful phase was observed in the alloy.M23C6-type carbides discretely distributed nearby grain boundaries as the alloy was aged at above840 °C. The microhardness decreased with increasing aging temperature. The coarsening of γ′ led to the increment of microhardness at 780 °C and 810 °C for a short aging time, and a signi fi cant decrease in microhardness after aging at 840 °C. The aging temperature had more signi fi cant role on the microstructure than holding time. Therefore, to obtain optimum strengthening effect for this alloy, the aging temperature should not exceed 810 °C.

关键词： Ultra-supercritical power plant Ni – Fe based superalloy Heat treatment Microstructure Microhardness

Cause and Prevention Measures of Concrete Cracks during the Construction of Road and Bridge Engineering

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Frontiers Research of Architecture and Engineering 2018年第3期1卷 80-83页

作者： jingbo yan Fushun Shuntong Highway Engineering Co. Ltd.FushunLiaoning113000China

Road and bridge engineering is an indispensable part of socialist economic construction in China, whose construction quality significantly affects the infrastructure construction level in the whole society. To meet the rapid economic development of various regions, construction scale and quantity of road and bridge engineering have been continuously expanded and increased, therefore, higher requirements for construction quality and construction standard are also presented. During the construction of road and bridge engineering, concrete crack is a key problem which affects the construction quality. In this regard, this paper analyzes cause and prevention measures of concrete cracks during the construction of road and bridge engineering, and hopes to provide construction personnel with valuable references.

关键词： Road and bridge engineering Concrete crack Prevention measure

Analysis of Common Diseases and Construction Treatment Technologies of Road and Bridge Engineering

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Frontiers Research of Architecture and Engineering 2018年第2期1卷 38-42页

作者： jingbo yan Fushun Shuntong Highway Engineering Co. Ltd.FushuanLiaoning113000China

In recent years, the rapid growth of the number of private cars has greatly increased the traffic pressure, so the quality of roads and bridges should be further improved. The paper expounds the related matters of road and bridge engineering from three aspects. Firstly, it expounds the construction principles of road and bridge engineering, which are regarded as the theoretical basis of follow-up research. Secondly, it analyzes the common diseases of road and bridge engineering, including bridgehead damage, rein-forcement corrosion, and subgrade uneven settlement, etc. Finally, it puts forward the construction treatment technology of road and bridge engineering on the basis of the construction principles and taking the common diseases as reference.

关键词： Road and bridge engineering Common diseases Construction treatment technology

Co/Fe oxide and Ce_(0.8)Gd_(0.2)O_(2-δ) composite interlayer for solid oxide electrolysis cell

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Journal of Energy Chemistry 2016年第5期25卷 840-844页

作者： jingbo yan Lei Shang Zhe Zhao Dingrong Ou Mojie Cheng Division of Fuel Cells Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

A composite interlayer comprised of gadolinia doped ceria（GDC） and Co/Fe oxide was prepared and investigated for solid oxide electrolysis cell with yttrium stabilized zirconia（YSZ） electrolyte and LaSrCoFeO（LSCF） anode. The interlayer was constructed of a base layer of GDC and a top layer of discrete CoO/FeCoOparticles. The presence of the GDC layer drastically alleviated the undesired reactions between LSCF and YSZ, and the presence of Co/Fe oxide led to further performance improvement. At 800 °C and 45% humidity, the cell with 70% Co/Fe-GDC interlayer achieved 0.98 A/cmat 1.18 V, 14% higher than the cell without Co/Fe oxide. Electrochemical impedance spectroscopy（EIS） revealed that with higher Co/Fe content, both the ohmic resistance and the polarization resistance of the cell were reduced. It is suggested that Co/Fe oxide can react with the Sr species segregated from LSCF and Sr（Co,Fe）O, a compound with high catalytic activity and electronic conductivity. The Sr-capturing ability of Co/Fe oxide in combination with the Sr-blocking ability of GDC layer can effectively suppress the undesired reaction between LSCF and YSZ, and consequently improve the cell performance.

关键词： Solid oxide electrolysis cell Ceria interlayer Cobalt oxide Sr segregation

夫妻共同持股与企业创新投入:基于婚姻契约的视角

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管理工程学报 2024年第4期38卷 17-35页

作者：陈元贺小刚闫静波彭屹上海财经大学商学院上海200433 上海财经大学浙江学院工商管理系浙江金华321000 上海交通大学安泰经济与管理学院上海200030

夫妻组合作为中国家族企业中最为常见的治理模式之一,其在企业战略决策中的作用正日益突显。本文以2008—2016年中国家族上市公司为研究样本,实证分析了夫妻共同持股对企业创新投入的影响及其制约机制与内在机理。研究结果表明:(1)相较... 详细信息

夫妻组合作为中国家族企业中最为常见的治理模式之一,其在企业战略决策中的作用正日益突显。本文以2008—2016年中国家族上市公司为研究样本,实证分析了夫妻共同持股对企业创新投入的影响及其制约机制与内在机理。研究结果表明:(1)相较于其他家族治理模式,夫妻共同持股更有利于促进企业创新投入,且该结果在利用工具变量法、倾向匹配得分法、安慰剂检验等多种稳健性检验后依然成立;(2)家族系统的夫妻差异,比如教育水平与婚前嵌入的儒家文化差异激发了夫妻间的关系冲突,将显著弱化夫妻共同持股对企业创新投入的促进作用。企业系统的经营困境,比如当前组织下滑与预期盈利压力激发了夫妻间的同心效应,有助于强化夫妻共同持股对企业创新投入的促进作用;(3)进一步研究发现,夫妻共同持股促进企业创新投入的关键在于长期导向的传导效应。本文基于婚姻契约的独特性验证了夫妻组合模式的创新激励效应,为深入理解家族企业的创新问题提供了新的理论视角。

关键词：夫妻共同持股家族企业婚姻契约企业创新投入长期导向

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电站空冷散热器动态传热特性研究

华北电力大学学报（自然科学版） 2020年第2期47卷 89-94页

作者：闫景波杨立军华北电力大学能源动力与机械工程学院北京102206

建立了空冷散热器空气侧、水侧和管壁的热平衡偏微分方程,采用改进欧拉法对离散后的方程进行求解。获得了迎面风速、循环水质量流量和入口水温阶跃变化时散热器的动态响应特性,以及变量变化程度对散热器动态过程的影响。结果表明:扰动... 详细信息

建立了空冷散热器空气侧、水侧和管壁的热平衡偏微分方程,采用改进欧拉法对离散后的方程进行求解。获得了迎面风速、循环水质量流量和入口水温阶跃变化时散热器的动态响应特性,以及变量变化程度对散热器动态过程的影响。结果表明:扰动变量阶跃变化时,变化程度越大,对应的动态响应曲线变化幅度也越大。迎面风速增加时,空气和循环水出口温度降低;循环水质量流量和入口水温增加时,空气和循环水出口温度均增加。迎面风速和循环水质量流量越大,动态响应时间越短;循环水入口水温变化时,动态响应时间不变。

关键词：空冷散热器动态特性迎面风速循环水质量流量

清代英国东印度公司广州商馆大班小斯当东的礼单和画押

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地方文化研究 2023年第1期11卷 44-51页

作者：颜景波山东文化产业职业学院山东青岛266600

小斯当东是19世纪中英关系中的重要人物。这位清代中期英国东印度公司驻广州商馆的大班,经常出现在中外文献和中英外交活动中,一生与中国结下不解之缘。缘于小斯当东学习中国传统文化,采取中国传统交际手段,使用中国传统文书格式,以期... 详细信息

小斯当东是19世纪中英关系中的重要人物。这位清代中期英国东印度公司驻广州商馆的大班,经常出现在中外文献和中英外交活动中,一生与中国结下不解之缘。缘于小斯当东学习中国传统文化,采取中国传统交际手段,使用中国传统文书格式,以期获得清朝官府和广州十三行商的认同,力图推动中英商贸往来和实现政治诉求。最新发现小斯当东的礼单和画押,成为了解这个“中国通”的具体例证。

关键词：小斯当东广州十三行礼单画押