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Damping and Mechanical Properties of Cocured Composite Laminates with Embedded Perforate Viscoelastic Layer

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Journal of Materials Science & Technology 2009年第4期25卷 543-546页

作者： lijian Pan Boming zhang TCentre for Composite Materials and Structure Harbin Institute of Technology Harbin 150080 China

The composite laminates with embedded acrylonitrile butadiene rubber （NBR） layer were fabricated by cocuring process. The embedded layers were perforated with a series of small holes to allow resin to flow through the damping layer and completely couple the structure to improve bending stiffness and interlaminar shearing strength of these cocured composite laminates. The damping, bending stiffness and shearing strength of these composite laminates with different perforation diameters were investigated. The experimental results show that increasing the perforation diameter leads to significant decreases in damping and significant increase in bending stiffness up to an area ratio of 7.065%. The area ratio here is defined as the ratio of perforation area to the total damping area. Beyond the area ratio of 7.065%, increasing the diameter to an area ratio of 50.24% results in only a slight variation in damping and bending stiffness. Moreover, increasing the perforation diameter does not always increase the shearing strength of the embedded viscoelastic layer. The shearing strength of embedded viscoelastic layer increases only when the area ratio is greater than 19.625%; instead, it will decrease.

关键词： Composite laminates Perforate viscoelastic layer Cocured Damping Mechanical Properties

Multi-objective Optimization of Co-cured Composite Laminates with Embedded Viscoelastic Damping Layer

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Journal of Materials Science & Technology 2009年第5期25卷 708-712页

作者： lijian Pan Boming zhang Fuhong Dai Centre for Composite Materials and Structure Harbin Institute of Technology Harbin 150080 China

Presented herein is a methodology for the multi-objective optimization of damping and bending stiffness of cocoured composite laminates with embedded viscoelastic damping layer. The embedded viscoelastic damping layer is perforated with a series of small holes, and the ratio of the perforation area to the total damping area is the design variable of the methodology. The multi-objective optimization is converted into a single-objective problem by an evaluation function which is a liner weigh sum of the two sub-objective functions. The proposed methodology was carried out to determine the optimal perforation area ratios of two viscoelstic layers with different perforation distance embedded in two composite plates. Both the optimal perforation area ratios are approximate to 2.2%. However, the objective value of the plate with greater perforation distance in embedded viscoelatic layer is much greater.

关键词： Composite laminates Viscoelastic damping layer Co-cured Multi-objective optimization

Study on Robot Grasping System of SSVEP-BCI Based on Augmented Reality Stimulus

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Tsinghua Science and Technology 2023年第2期28卷 322-329页

作者： Shangen zhang Yuanfang Chen lijian zhang Xiaorong Gao Xiaogang Chen School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China Beijing Institute of Mechanical Equipment Beijing 100854China Department of Biomedical Engineering School of MedicineTsinghua UniversityBeijing100084China Institute of Biomedical Engineering Chinese Academy of Medical Sciences and Peking Union Medical CollegeTianjin 300192China

Although notable progress has been made in the study of Steady-State Visual Evoked Potential(SSVEP)-based Brain-Computer Interface(BCI),several factors that limit the practical applications of BCIs still *** of these factors is the importability of the *** this study,Augmented Reality(AR)technology was introduced to present the visual stimuli of SSVEP-BCI,while the robot grasping experiment was designed to verify the applicability of the AR-BCI *** offline experiment was designed to determine the best stimulus time,while the online experiment was used to complete the robot grasping *** offline experiment revealed that better information transfer rate performance could be achieved when the stimulation time is 2 *** of the online experiment indicate that all 12 subjects could control the robot to complete the robot grasping task,which indicates the applicability of the AR-SSVEP-humanoid robot(NAO)*** study verified the reliability of the AR-BCI system and indicated the applicability of the AR-SSVEP-NAO system in robot grasping tasks.

关键词： Steady-State Visual Evoked Potential(SSVEP) Brain-Computer Interface(BCI) Augmented Reality(AR) robot grasping system

Reduction Removal of Cr(Ⅵ)from Wastewater by COf Deriving from Formate Anion Based on Activated Carbon Catalyzed Persulfate

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Chemical Research in Chinese Universities 2020年第5期36卷 870-876页

作者： ZHOU Rui LI Tingting zhang lijian JIAO Xinqian Key Laboratory of Groundwater Resources and Environment Ministry of EducationJilin Provincial Key Laboratory of Water Resource and EnvironmentCollege of New Energy and EnvironmentJilin UniversityChangchun 130021P.R.China

As a strong reducing radical,carbon dioxide anion radical(CO·-2)can be generated by initiating sulfate radical(SO·-4)in the presence of tonnate anions(FA)for Cr(Ⅵ)***,activated carbon(AC)-catalyzed persultate(PS)oxidation is an economically justifiable,enⅥronmentally friendly,and easy-to-scalemethod to produce SO·-4 The complete removal of Cr(Ⅵ)was achieved within 280 min for an initial Cr(Ⅵ)concentration of 50 mg/L under the optional condition of c(AC)=1 g/L,[PS]0=1O mmol/L,[FA]0=10 mmol/L,T=30℃,and unadjusted *** the molar ratio of FA to PS was greater than or equal to 1,the system maintained a strong reduction *** mechanism investigation confirmed that FA was converted to carboxyl anion radical(CO2·-2)as the predominant radical tor Cr(Ⅵ)*** novel system may offer a potential plattbnn teclmology tor Cr(Ⅵ)wastewater treatment.

关键词： Cr(Ⅵ) Activated carbon Carboxyl anion radical Persulfate:Reduction

首台“陆改船”用重型燃气轮机自主改型设计实践

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热力透平 2024年第2期53卷 80-83,88页

作者：张立建唐健崔耀欣上海电气燃气轮机有限公司上海200240 上海汽轮机厂有限公司上海200240

某海上浮式发电项目中的燃气轮机,以引进型小F级燃气轮机为母型进行自主改型设计,其为国内首台套陆地重型燃气轮机在发电船上的应用。介绍了母型机的技术特点,并重点阐述了改型设计内容,包括轴系总体布置设计、轴系与钢结构基础耦合设... 详细信息

某海上浮式发电项目中的燃气轮机,以引进型小F级燃气轮机为母型进行自主改型设计,其为国内首台套陆地重型燃气轮机在发电船上的应用。介绍了母型机的技术特点,并重点阐述了改型设计内容,包括轴系总体布置设计、轴系与钢结构基础耦合设计、带挠性联轴器的减速箱设计、轴承适应性设计、支撑的加固与匹配设计、海工化防腐设计、全新机岛布置及辅机优化设计等。该改型设计经验可以为其他型号“陆改船”用燃气轮机提供参考。

关键词：燃气轮机重型小F级联合循环发电发电船

Robust secure transmission for multiuser MISO systems with probabilistic QoS constraints

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Science China(Information Sciences) 2016年第2期59卷 126-138页

作者： lijian zhang Liang JIN Wenyu LUO Chunming WANG Yanqun TANG National Digital Switching System Engineering & Technological Research Center School of Information Systems Engineering Zhengzhou Information Science and Technology Institute

This paper considers a unicast multiuser multiple-input single-output(MISO) downlink system overheard by multiple single-antenna eavesdroppers. The objective is to jointly design the beamforming vectors and the artificial noise(AN) covariance matrix with imperfect channel state information(CSI) at the transmitter,such that the total transmit power is minimized while satisfying probabilistic quality of service(Qo S) constraints at legitimate users and the eavesdroppers. Using Bernstein-type inequalities and the S-procedure, we recast the non-convex power minimization problem as two different convex semidefinite programs(SDPs) which can be solved using interior-point methods. Simulation results show that the proposed methods outperform a nonrobust method and the ones using the isotropic AN.

关键词： physical layer security artificial noise imperfect CSI robust beamforming semidefinite program outage probability

新时代我国政府购买公共服务市场化面临的困境与路径选择

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云南行政学院学报 2024年第1期26卷 56-65页

作者：张礼建李文靖陈彪重庆大学马克思主义学院重庆大学公共管理学院重庆大学科学文化传播中心重庆大学科学技术与社会研究所(STS) 重庆市自然辩证法研究会重庆市科技创新融合教育协会重庆市哲学学会重庆市逻辑学会四川文理学院政法学院

政府购买公共服务“圈内化”现象突出,市场化程度滞后,严重影响公共服务供给效率。研究发现:公共产品的模糊性、购买制度的模糊性和交易关系的模糊性所构成的政府购买信息非标准化是影响政府购买公共服务市场化的主要“症结”;不同社会... 详细信息

政府购买公共服务“圈内化”现象突出,市场化程度滞后,严重影响公共服务供给效率。研究发现:公共产品的模糊性、购买制度的模糊性和交易关系的模糊性所构成的政府购买信息非标准化是影响政府购买公共服务市场化的主要“症结”;不同社会组织距离政府中心的位置远近直接影响其项目获取能力,紧密组织具有赢得政府购买的天然优势,独立组织在政府购买中处于相对劣势,松散组织游离于二者之间;政府的强权威和“稳中求进”的思维惯性往往倾向于“圈内购买”,造成政府购买公共服务难以市场化。建议通过建立公共服务市场化清单,明晰公共服务边界;完善购买制度体系,强化制度约束;加大培育市场化社会组织,强化功能引导;优化政府公共服务市场化购买机制,提升政府购买公开透明度等举措推进政府购买公共服务市场化。

关键词：新时代购买服务公共服务市场化社会组织

HS-SPME-GC-MS分析武夷岩茶呈香挥发性物质

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食品与生物技术学报 2024年第5期43卷 110-121页

作者：梁轶琳张灵枝戴浩民王治会张黎剑荣杰峰岳彬孙威江福建农林大学园艺学院福建福州350002 福建农林大学海峡两岸特色作物安全生产省部共建协同创新中心福建福州350002 泉州海关综合技术服务中心福建泉州362000 六禾(武夷山)茶业有限公司福建武夷山354300

为探究4个茶树品种所制武夷岩茶风味特征、挥发性物质的差异及其品种香形成的物质基础,使用定量描述分析(quantitative description analysis,QDA)、顶空固相微萃取-气质联用(headspace-solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)、香气活力值(odor activity value,OAV)分析等方法结合化学计量学,对4个茶树品种所制武夷岩茶进行风味特征比对与挥发性物质差异性分析。结果表明,4个茶树品种所制的武夷岩茶香气属性相似,花果香显,‘肉桂’品种所制武夷岩茶具有特殊且明显的桂皮香。使用化学计量学分析并以VIP>1且OAV可计算为准则,共计14种香气成分被认为是4个茶树品种所制武夷岩茶香气差异的原因。芳樟醇、β-紫罗酮、吲哚对4个茶树品种所制武夷岩茶花香的形成具有关键作用;β-环柠檬醛、香叶醇、苯乙醛对‘水仙’,芳樟醇氧化物II对‘瑞香’,(E)-2-壬烯醛对‘黄观音’所制武夷岩茶的花香呈现具有突出贡献;苯乙醇、己酸己酯、反式肉桂醛可能与‘肉桂’所制武夷岩茶的桂皮香形成有关。研究结果为武夷岩茶香型多元化及不同品种的品种香关键呈香物质基础研究提供理论参考。

关键词：武夷岩茶茶树品种呈香物质关键挥发性成分

External Dependent Economy and Structural Real Estate Bubbles in China

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China & World Economy 2008年第1期16卷 34-50页

作者： lijian Sun Shengxing zhang Economics School

This study explores the relationship between external dependent economic structure, surplus monetary liquidity and real estate bubbles in China. Employing monthly data from 28 Chinese provinces over the period 2004-2005, we test whether real estate bubbles are caused by structural surplus monetary liquidity, ccontrolling other possible factors. Our empirical findings show that the growth of private savings in the banking sector, as an index of surplus monetary liquidity, ferments real estate bubbles regardless of the different development level across the 28 provinces.

关键词： private saving real estate bubble ripple effect surplus monetary liquidity