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基于逆Leidenfrost效应的多孔地聚合物微球孔结构及pH缓冲性能

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建筑材料学报 2024年第3期27卷 267-274页

作者：李方贤王亚松张志博韦江雄余其俊华南理工大学材料科学与工程学院广东广州510641

以水玻璃、矿渣粉为材料,基于逆Leidenfrost效应制备了多孔地聚合物微球,研究了其孔结构及pH缓冲性能.结果表明:改变水玻璃掺量和水固比可以调控多孔地聚合物微球的孔结构和pH缓冲性能;当水固比为1.0、水玻璃掺量由4%增大至8%时,微球的... 详细信息

以水玻璃、矿渣粉为材料,基于逆Leidenfrost效应制备了多孔地聚合物微球,研究了其孔结构及pH缓冲性能.结果表明:改变水玻璃掺量和水固比可以调控多孔地聚合物微球的孔结构和pH缓冲性能;当水固比为1.0、水玻璃掺量由4%增大至8%时,微球的孔隙率、中位孔径和孔比表面积均减小,pH值波动范围为1.50~1.90;当水玻璃掺量为4%、水固比由1.0增大至1.2.,微球的孔隙率、中位孔径和孔比表面积均增大,pH值波动范围超过2.00;与双氧水直接发气法制备的多孔地聚合物相比,基于逆Leidenfrost效应制备的多孔地聚合物具有更好的pH缓冲性能和更高的OH-累积浸出量.

关键词：逆Leidenfrost效应矿渣地聚合物孔结构 pH缓冲性能

CONSUMER-DRIVEN GROUP BUYING： TRICK OR TREAT TO RETAIL STORES？

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Journal of Systems Science and Systems Engineering 2018年第1期27卷 1-23页

作者： qijun Qiu Li Jiang Department of Logistics and Maritime Studies Faculty of Business The Hong Kong Polytechnic University Hong Kong SAR China

Group buying （GB） has emerged and evolved into various forms over the past decade. We investigate a distinct form of GB, namely consumer-driven group buying, whereby some consumers form purchase groups to visit stores together and negotiate for discounts. We refer to these consumers as GB consumers that differ from regular consumers who visit stores individually and pay regular prices. Visited by a purchase group, a store has to make an immediate decision to serve their demand in its entirety. Turned down by the first store it visits, the purchase group continues to visit the other store. After accommodating GB demand, the stores use remaining stocks to serve regular consumers. We demonstrate that GB can be a treat to stores that adopt proper policies to utilize it as an instrument to reach consumers. The stores are able to accommodate group demand at a price lower than regular price in most circumstances but still manage to earn stable profits. The presence of regular consumers has a subtle effect on equilibrium formation, by strengthening the stores＇ power in negotiating with GB consumers to make group price weakly increase with group size. Moreover, competing stores are able to manipulate the interactions between purchase groups and collectively earn a higher total profit than a monopolist store when GB consumers account for a small fraction of market base and competition is intense.

关键词： Group buying pricing retailing and competitive strategy

深基坑双排微型桩-锚-撑组合支护结构受力与变形特性

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中南大学学报（自然科学版） 2024年第6期55卷 2295-2309页

作者：闫楠郝增明白晓宇张立孙林娜张启军青岛理工大学土木工程学院山东青岛266520 青岛业高建设工程有限公司山东青岛266022

为深入研究深厚杂填土地层深基坑微型桩-锚-撑组合支护结构随基坑开挖的受力与变形演化规律,首先,依托青岛市某深基坑工程开展双排微型桩-锚-撑原位试验,分析开挖工况下前、后排桩的桩身弯矩分布规律;然后,结合ABAQUS有限元模拟方法,明... 详细信息

为深入研究深厚杂填土地层深基坑微型桩-锚-撑组合支护结构随基坑开挖的受力与变形演化规律,首先,依托青岛市某深基坑工程开展双排微型桩-锚-撑原位试验,分析开挖工况下前、后排桩的桩身弯矩分布规律;然后,结合ABAQUS有限元模拟方法,明确微型桩、预应力锚索与钢支撑之间的协同作用及基坑变形规律;最后,揭示微型桩桩径变化、支护结构作用对桩身受力及基坑变形的影响机制。研究结果表明:增加开挖深度引起桩身正弯矩和负弯矩不断增大,极值点位置不断下移,桩身弯矩整体呈正“S”形分布;开挖至基底,前排桩的桩身反弯点分别位于钢支撑下方0.5 m和开挖面位置,后排桩的桩身反弯点分别位于钢支撑下方0.5 m和开挖面下方1.0 m范围内;基坑开挖竖向影响范围约为1.35H(H为基坑开挖深度),桩径增加近1倍,土体水平位移仅减少约51%,且随桩径继续增加,其对于限制基坑变形效果不显著;相较于桩锚支护结构,桩-锚-撑支护结构作用下,前、后排桩的最大水平位移分别减小34.9%和2..3%,基坑土体的最大水平位移减小46.0%。

关键词：深基坑微型桩锚索钢支撑原位试验有限元模拟

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塞来昔布对创伤性异位骨化跟腱组织相关因子表达及生物力学的影响

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浙江医学 2024年第17期46卷 1797-1803页

作者：冯祁军蒋毅嘉兴市第一医院骨科 314001

目的探讨塞来昔布对创伤性异位骨化(HO)跟腱组织相关因子表达及生物力学的影响。方法采用随机数字表法将60只实验兔分为正常组、模型组、塞来昔布低剂量组、塞来昔布高剂量组、塞来昔布用药3周组、塞来昔布用药6周组,每组10只。除正常组... 详细信息

目的探讨塞来昔布对创伤性异位骨化(HO)跟腱组织相关因子表达及生物力学的影响。方法采用随机数字表法将60只实验兔分为正常组、模型组、塞来昔布低剂量组、塞来昔布高剂量组、塞来昔布用药3周组、塞来昔布用药6周组,每组10只。除正常组外,其余实验兔均建立创伤性HO模型。造模成功后,塞来昔布低、高剂量组分别给予塞来昔布2.、60 mg/(kg·d)灌胃,连续10 d;塞来昔布用药3周组给予塞来昔布10 mg/(kg·d)灌胃,连续3周;塞来昔布用药6周组给予塞来昔布10 mg/(kg·d)灌胃,连续6周;正常组与模型组均给予0.9%氯化钠溶液2.mL灌胃,连续10 d。使用ELISA试剂盒检测血清CRP水平;使用皮温计记录肢体皮温,以肢体肿胀评分评估肿胀程度;X线摄片观察新骨形成情况;采用三点弯曲实验法检测兔右跟腱生物力学参数;采用qRT-PCR检测跟腱组织骨形成蛋白(BMP)-2.BMP-4;免疫组化法检测跟腱组织环氧合酶-2.COX-2.;Western blot法检测跟腱组织转化生长因子-β(TGF-β)1、Smad1蛋白表达水平。结果与正常组比较,模型组血清CRP水平、平均皮温、肿胀程度及新骨形成评分、跟腱组织BMP-2.BMP-4 mRNA表达水平、COX-2.度值和TGF-β1、Smad1蛋白表达水平均升高(均P2.BMP-4 mRNA表达水平,COX-2.度值和TGF-β1、Smad1蛋白表达水平均降低(均P2.BMP-4 m RNA表达水平、COX-2.度值和TGF-β1、Smad1蛋白表达水平均降低(均P0.05)。结论不同剂量及作用时间下塞来昔布均可改善创伤性HO兔的生物力学,降低炎性反应,其作用机制可能与下调跟腱组织COX-2.BMP-2.BMP-4表达水平,抑制TGF-β/Smads信号通路活性有关。

关键词：塞来昔布创伤性异位骨化环氧合酶-2 骨形成蛋白

Parametric analyses for synthetic jet control on separation and stall over rotor airfoil

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Chinese Journal of Aeronautics 2014年第5期27卷 1051-1061页

作者： Zhao Guoqing Zhao qijun National Key Laboratory of Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics

Numerical simulations are performed to investigate the effects of synthetic jet control on separation and stall over rotor airfoils. The preconditioned and unsteady Reynolds-averaged Navier–Stokes equations coupled with a k x shear stream transport turbulence model are employed to accomplish the flowfield simulation of rotor airfoils under jet control. Additionally,a velocity boundary condition modeled by a sinusoidal function is developed to fulfill the perturbation effect of periodic jets. The validity of the present CFD procedure is evaluated by the simulated results of an isolated synthetic jet and the jet control case for airfoil NACA0015. Then, parametric analyses are conducted specifically for an OA2.3 rotor airfoil to investigate the effects of jet parameters（forcing frequency, jet location and momentum coefficient, jet direction, and distribution of jet arrays） on the control effect of the aerodynamic characteristics of a rotor airfoil. Preliminary results indicate that the efficiency of jet control can be improved with specific frequencies（the best lift-drag ratio at F＋= 2.0） and jet angles（40 or 75） when the jets are located near the separation point of the rotor airfoil. Furthermore, as a result of a suitable combination of jet arrays, the lift coefficient of the airfoil can be improved by nearly 100%, and the corresponding drag coefficient decreased by2..5% in comparison with the single point control case.

关键词： Flow control Flow separation Parametric analysis Rotor Synthetic jet

Experiments on unsteady vortex flowfield of typical rotor airfoils under dynamic stall conditions

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Chinese Journal of Aeronautics 2016年第2期29卷 358-374页

作者： Wang Qing Zhao qijun National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics

A new experiment for airfoil dynamic stall is conducted by employing the advanced par- ticle image velocimetry （PIV） technology in an open-return wind tunnel. The aim of this experimen- tal investigation is to demonstrate the influences of different motion parameters on the convection velocity, position and strength of leading edge vortex （LEV） of airfoil under different dynamic stall conditions. Two different typical rotor airfoils, OA2.9 and SC1095, are measured at different free stream velocities, oscillation frequencies, and angles of attack. It is demonstrated by the measured data that the airfoil with larger leading edge radius could notably decrease the strength of LEV. The angle of attack （AoA） of airfoil can obviously influence the dynamic stall characteristics of airfoil, and the LEV would be effectively inhibited by decreasing the mean pitch angle. In addition, the con- vection velocity of LEV is estimated in this measurement, and the results demonstrate that the influ- ence of airfoil shape on convection velocity of LEV is limited, but the convection velocity of LEV would be increased by enlarging the oscillation frequency. Meanwhile, the convection velocity of LEV is a time variant value, and this value would increase as the LEV convects to the trailing edge of airfoil.

关键词： Convection velocity Dynamic stall Leading edge vortex PIV Rotor airfoil

Learning Gait of Quadruped Robot without Prior Knowledge of the Environment

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 1068-1074页

作者： XU Tao CHEN qijun College of Electronic and Information Engineering Tongji UniversityShanghai 201804China

Walking is the basic skill of a legged robot, and one of the promising ways to improve the walking performance and its adaptation to environment changes is to let the robot learn its walking by itself. Currently, most of the walking learning methods are based on robot vision system or some external sensing equipment to estimate the walking performance of certain walking parameters, and therefore are usually only applicable under laboratory condition, where environment can be pre-defined. Inspired by the rhythmic swing movement during walking of legged animals and the behavior of their adjusting their walking gait on different walking surfaces, a concept of walking rhythmic pattern（WRP） is proposed to evaluate the walking specialty of legged robot, which is just based on the walking dynamics of the robot. Based on the onboard acceleration sensor data, a method to calculate WRP using power spectrum in frequency domain and diverse smooth filters is also presented. Since the evaluation of WRP is only based on the walking dynamics data of the robot＇s body, the proposed method doesn＇t require prior knowledge of environment and thus can be applied in unknown environment. A gait learning approach of legged robots based on WRP and evolution algorithm（EA） is introduced. By using the proposed approach, a quadruped robot can learn its locomotion by its onboard sensing in an unknown environment, where the robot has no prior knowledge about this place. The experimental result proves proportional relationship exits between WRP match score and walking performance of legged robot, which can be used to evaluate the walking performance in walking optimization under unknown environment.

关键词： quadruped locomotion gait learning evolution algorithm

中国栽培海藻碳汇经济价值时空分异及影响因素

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水产学报 2024年第10期48卷 171-184页

作者：余悦儒杨锐陈海敏陈娟娟骆其君宁波大学浙江省海洋生物工程重点实验室宁波大学海洋学院

工业革命以来，人类活动导致大气中的温室气体浓度迅速攀升，严重影响了全球气候。开发蓝碳产业成为人们应对气候变化的重要举措。栽培海藻碳汇是蓝碳的重要组成部分。本研究以中国8个沿海省份栽培海藻数据为基础，测算其碳汇总经济价... 详细信息

工业革命以来，人类活动导致大气中的温室气体浓度迅速攀升，严重影响了全球气候。开发蓝碳产业成为人们应对气候变化的重要举措。栽培海藻碳汇是蓝碳的重要组成部分。本研究以中国8个沿海省份栽培海藻数据为基础，测算其碳汇总经济价值，并分析其时空分异特征；采用对数平均迪氏指数法(LMDI)解析中国栽培海藻碳汇总经济价值的影响因素。结果显示，2.09—2.2.年，中国栽培海藻碳汇量及其总经济价值整体呈上升趋势，2.2.年分别达到87万t和488亿元。不同栽培海藻的碳汇量，从高到低依次为海带、江蓠、紫菜、裙带菜和其他(羊栖菜、麒麟菜、石花菜和浒苔)；单位面积碳去除能力，从高到低依次为海带、江蓠、裙带菜、其他和紫菜。福建、山东和辽宁三个省份的栽培海藻碳汇总经济价值较高，其余省份则较低。养殖效率效应(EFE)和养殖面积效应(AE)是栽培海藻碳汇总经济价值的主要驱动因素。研究表明，中国栽培海藻的碳汇潜力不容忽视，能够创造巨大的经济效益。栽培海藻的碳汇能力及其总经济价值存在一定的种间差异，可通过合理调整栽培物种和结构来提高海藻碳汇及其总经济价值。应从政府部门、科研单位及从业人员和社会公众三个层面出发，重视栽培海藻碳汇等渔业碳汇的功能和价值，促进渔业高质量发展，为减缓全球气候变暖，实现“双碳”目标做出更大贡献。

关键词：栽培海藻碳汇经济价值时空分异影响因素

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天津市老年人体医融合知信行现状及影响因素

护理研究 2024年第9期38卷 1533-1537页

作者：敬晔祺陈启俊高尚尚天津中医药大学天津301617

目的:调查天津市老年人体医融合知信行现况,探索体医融合在老年人群实施的影响因素。方法:2.2.年7月—12.采用自制一般资料调查表及体医融合老年人知信行问卷对天津市406名老年人进行调查。结果:406名老年人体医融合总分标准分为53.8分... 详细信息

目的:调查天津市老年人体医融合知信行现况,探索体医融合在老年人群实施的影响因素。方法:2.2.年7月—12.采用自制一般资料调查表及体医融合老年人知信行问卷对天津市406名老年人进行调查。结果:406名老年人体医融合总分标准分为53.8分,体医融合知识为49.2.,体医融合态度为75.6分,体医融合行为为38.0分。老年人的月收入、生活满意状况与健康状况是社区老年人体医融合知信行水平的影响因素(P<0.05)。结论:天津市老年人体医融合知信行水平有待提高,应基于老年人的实际需求完善体医融合宣传及发展方案,为不同特征的老年人提供认知和实践体医融合的渠道和方案。

关键词：老年人体医融合知识信念行为影响因素调查研究