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多维地震下钢管混凝土柱-组合梁框架结构体系抗震性能分析 被引量:4
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作者 许云龙 丁发兴 +5 位作者 吕飞 潘志成 罗靓 尹国安 陈明 余志武 《钢结构(中英文)》 2023年第12期27-38,共12页
基于柱端拉筋对钢管混凝土柱、钢管混凝土柱-组合梁节点和钢管混凝土柱-组合梁平面框架结构抗震性能影响的试验研究成果,建立了钢管混凝土柱-组合梁空间框架结构动力时程分析的三维实体-壳单元模型,探讨了柱端拉筋和主梁加高等增强约束... 基于柱端拉筋对钢管混凝土柱、钢管混凝土柱-组合梁节点和钢管混凝土柱-组合梁平面框架结构抗震性能影响的试验研究成果,建立了钢管混凝土柱-组合梁空间框架结构动力时程分析的三维实体-壳单元模型,探讨了柱端拉筋和主梁加高等增强约束措施、削减钢梁跨中腹板高度的变截面组合梁以及多维地震波对结构抗震性能的影响规律,分析了不同地震波强度作用下该类组合框架结构的位移响应、轴压比时程曲线、应力-应变等曲线,以及结构塑性耗能分配机制、塑性铰形成与发展规律和结构刚度损伤演化规律等抗震性能指标。有限元计算结果表明:1)柱端拉筋和主梁加高等增强约束措施均能有效提升组合框架结构抗震性能而减小结构刚度损伤,且地震波强度越大作用效果越明显;相同地震波作用时,柱端拉筋增强约束措施比主梁加高增强约束措施更有效,而两种增强约束措施共同作用则能进一步提升组合结构的极限抗震能力。2)柱端拉筋增强约束措施能够降低钢管壁与混凝土间界面滑移,增强混凝土的耗能能力,降低钢管混凝土柱塑性耗能占比,提升钢梁塑性耗能占比,提升结构总塑性耗能;此外,柱端拉筋增强约束措施还可减少组合框架柱端塑性铰并增加梁端塑性铰的数量,延缓柱端“压铰”的出现,延长“压铰”向“拉铰”转变的过程。3)降低钢梁跨中腹板高度的变截面组合梁对框架结构抗震性能没有影响,采用该变截面组合梁的框架模型不仅能够满足结构基本功能要求,还可节省结构耗材、降低造价,进一步扩大建筑实用空间。4)与单向地震波作用相比,多维地震波作用下组合框架结构的极限抗震能力大幅下降,结构失效模式由剪切破坏转变为剪扭破坏。另外,三维地震波中竖向加速度对框架结构柱端轴压比有放大作用,而对楼层最大位移、层间位移角、塑性耗能和刚度损伤等方面则无明显影响。柱端拉筋增强约束措施对组合框架结构抗震性能仍有提升作用。 展开更多
关键词 钢-混凝土组合结构 多维地震 增强约束 塑性耗能 刚度损伤
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Meat quality traits of four Chinese indigenous chicken breeds and one commercial broiler stock 被引量:14
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作者 Rong-fa GUAN fei lyu +3 位作者 Xiao-qiang CHEN Jie-qing MA Han JIANG Chao-geng XIAO 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2013年第10期896-902,共7页
Meat quality traits of four genotypes of Chinese indigenous chicken [Ninghai chicken(NC),frizzle chicken(FC),Ninghai xiang chicken(XC),and Zhenning loquat chicken(LC)] and one genotype of commercial broiler [Arbor Acr... Meat quality traits of four genotypes of Chinese indigenous chicken [Ninghai chicken(NC),frizzle chicken(FC),Ninghai xiang chicken(XC),and Zhenning loquat chicken(LC)] and one genotype of commercial broiler [Arbor Acres plus broiler(AAB)] were analyzed.The indigenous chickens were raised before the commercial chickens in order to achieve the same final processed days.Indigenous chickens of NC,FC,XC,and LC showed significantly higher inosine-5′-monophosphate(IMP) content,shorter fiber diameter,and lower shear force than those of AAB(P<0.05).In the indigenous genotypes,NC and FC had significantly shorter fiber diameters and lower shear forces than XC and LC(P<0.05),and NC and XC had a higher IMP content than FC and LC(P<0.05).Moreover,the indigenous genotype of LC significantly displayed the highest protein content(P<0.05) in the five genotypes of birds,and no significant differences of protein content were found between the other genotypes of NC,FC,XC,and AAB(P>0.05).The indigenous chickens from FC displayed the highest total lipid content in the five bird genotypes(P<0.05).Significant differences of pH,color values of L* and a*,and drip loss for the five genotypes of birds were also observed.In conclusion,there were significant differences in the meat quality traits of the bird breeds selected in this study,and the indigenous chickens,especially the NC genotype,produced better quality meat as far as the IMP content,fiber diameters,and shear forces were concerned. 展开更多
关键词 Indigenous CHICKEN Commercial BROILER MEAT quality Fiber diameter Inosine-5′-monophosphate
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Performance optimization for high speed axial piston pump considering cylinder block tilt 被引量:6
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作者 Haogong XU Junhui ZHANG +6 位作者 Shoujun ZHAO Junyuan CHEN Weidi HUANG Xiaochen HUANG fei lyu Qi SU Bing XU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2023年第9期437-450,共14页
Increasing the rotating speed is considered as an efficient approach to upgrade the power-to-weight ratio in an axial piston pump,but penalized by more leakage and more severe wear resulting from the adverse cylinder ... Increasing the rotating speed is considered as an efficient approach to upgrade the power-to-weight ratio in an axial piston pump,but penalized by more leakage and more severe wear resulting from the adverse cylinder block tilt.Previous studies mainly focused on the bearing characteristic of the valve plate/cylinder block pair,but the spline coupling also plays a key role in the undesired cylinder block tilt,which has been little studied.A theoretical model for the rotating assembly is presented to investigate the effect of the spline coupling length on the cylinder block tilt and the performance of the valve plate/cylinder block pair.A typical high-speed axial piston pump with the displacement of 5.2 mL/r at 10000 r/min was studied by simulation and experiment.It shows that the optimal spline coupling length is one value increased by 2 mm from the original,bringing a remarkable leakage reduction under the high-speed condition by decreasing the cylinder block tilting angle.The experiment result matches well with the simulation.The influences of the spline coupling on the cylinder block tilt and the leakage were demonstrated. 展开更多
关键词 Cylinder block tilt High-speed axial piston pump LEAKAGE Spline coupling WEAR
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Raising the Speed Limit of Axial Piston Pumps by Optimizing the Suction Duct 被引量:2
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作者 Yu Fang Junhui Zhang +5 位作者 Bing Xu Zebing Mao Changming Li Changsheng Huang fei lyu Zhimin Guo 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第6期271-280,共10页
The maximum delivery pressure and the maximum rotational speed determine the power density of axial piston pumps.However,increasing the speed beyond the limit always accompanies cavitation,leading to the decrease of t... The maximum delivery pressure and the maximum rotational speed determine the power density of axial piston pumps.However,increasing the speed beyond the limit always accompanies cavitation,leading to the decrease of the volumetric efficiency.The pressure loss in the suction duct is considered a significant reason for the cavitation.Therefore,this paper proposes a methodology to optimize the shape of the suction duct aiming at reducing the intensity of cavitation and increasing the speed limit.At first,a computational fluid dynamics(CFD)model based on the full cavitation model(FCM)is developed to simulate the fluid field of the axial piston pump and a test rig is set to validate the model.Then the topology optimization is conducted for obtaining the minimum pressure loss in the suc-tion duct.Comparing the original suction duct with the optimized one in the simulation model,the pressure loss in the suction duct gets considerable reduction,which eases the cavitation intensity a lot.The simulation results prove that the speed limit can increase under several different inlet pressures. 展开更多
关键词 Axial piston pump Speed limit Topology optimization Suction duct CAVITATION
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Coupled evolution of piston asperity and cylinder bore contour of piston/cylinder pair in axial piston pump 被引量:2
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作者 fei lyu Junhui ZHANG +5 位作者 Shoujun ZHAO Kun LI Bing XU Weidi HUANG Haogong XU Xiaochen HUANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2023年第8期395-407,共13页
The wear condition of the piston/cylinder pair is crucial to the performance and reliability of the axial piston pump.The hard piston surface,the soft cylinder bore surface,and the interface oil film affects each othe... The wear condition of the piston/cylinder pair is crucial to the performance and reliability of the axial piston pump.The hard piston surface,the soft cylinder bore surface,and the interface oil film affects each other during the wear process.Specifically,in the mixed lubrication region,the geometry of the hard piston surface asperity directly affects the wear of soft cylinder bore surface,while the asperities may deform or even degrade when penetrating and sliding against the cylinder bore.So far,there is no suitable method to simulate their coupled evolution.This paper proposed a wear process simulation model considering the real-time interaction between the elasto-plastic deformation of the piston surface asperity,the wear contour of the cylinder bore,and the lubrication condition of the interface.An offline library of the elasto-plastic constitutive behavior of the asperity based on the finite element method(FEM)is established as a part of the simulation model to precisely analyze the deformation and degradation of the asperity and quickly invoke them in the numerical wear process simulation.The simulation and experimental results show that the piston asperity and the cylinder bore contour converge to a steady state after running-in for about 0.5 h.The distribution of the simulated asperity degradation and wear depth is also verified by the experiment. 展开更多
关键词 ASPERITY CONTOUR Coupled evolution Piston/cylinder pair Wear process
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Effects of concurrent chemoradiotherapy on immune function and tumor markers SCC-Ag and CYFRA21-1 in patients with esophageal carcinoma
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作者 Ling-Li Jin Zhi-Yuan Du +2 位作者 Guang-Xin Lu fei lyu Rui Shang 《Journal of Hainan Medical University》 2017年第16期90-93,共4页
Objective: To investigate the effects of concurrent chemoradiotherapy and radiotherapy alone on immune function and tumor markers SCC-Ag and CYFRA21-1 in patients with esophageal carcinoma. Method: A total of 84 patie... Objective: To investigate the effects of concurrent chemoradiotherapy and radiotherapy alone on immune function and tumor markers SCC-Ag and CYFRA21-1 in patients with esophageal carcinoma. Method: A total of 84 patients with esophageal cancer treated in our hospital from June 2015 to April 2017 were selected and randomly divided into the observation group and the control group with 42 cases each. The control group received radiotherapy only and irradiated by medical electron linear accelerator, radiotherapy for 6 weeks. The observation group was given radiotherapy and chemotherapy concurrently, 3 weeks for 1 courses, 2 cycles of chemotherapy. The fasting venous blood of patients in two groups were collected in the morning when patients were hospitalized and after chemotherapy, using flow cytometry to detect the immune function indexes of two groups of patients with esophageal cancer before and after treatment, including natural killer cells (NK), T suppressor cells (Ts), T helper cells (Th), Th/Ts and T lymphocytes (T total). The levels of serum SCC-Ag and CYFRA21-1 were detected by electrochemiluminescence assay. Results: There were no significant differences in the indexes of immune function between the two groups before treatment. Total T, the proportion of Th and Th/Ts in the two groups both increased significantly;the proportion of Ts decreased significantly;the difference was statistically significant. NK was higher than treatment before but not significantly. After treatment, the levels of T total, Th, Th/Ts in the observation group were significantly higher than the control group;the levels of NK and Ts were not significantly different. Before treatment, there was no significant difference in serum SCC-Ag and CYFRA21-1 between the two groups. After treatment, the serum SCC-Ag and CYFRA21-1 levels of the two groups were both significantly decreased;the serum levels of SCC-Ag and CYFRA21-1 in the observation group were significantly lower than the control group. Conclusion: Radiotherapy combined with chemotherapy of cisplatin and paclitaxel can improve the immune function and reduce serum SCC-Ag and CYFRA21-1 levels of esophageal cancer patients. This therapeutic schemes can be beneficial to increase the survival rate of patients with esophageal cancer. 展开更多
关键词 RADIOTHERAPY Chemotherapy ESOPHAGEAL cancer Immune function SCC-AG CYFRA21-1
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相同造价下几类方形截面桥墩抗震性能对比研究 被引量:3
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作者 李彪 吕飞 +3 位作者 孙浩 丁发兴 蔡勇强 张朝成 《钢结构(中英文)》 2024年第1期53-67,共15页
强震下传统钢筋混凝土桥墩抗震性能不足,而钢管混凝土具有更好的抗震性能。钢管混凝土墩在公路、高速公路、城市快速路和高速铁路等领域具有广阔的应用前景,近年来在桥梁结构中逐步推广应用。为提高桥墩的抗震韧性,结合当前各类桥墩抗... 强震下传统钢筋混凝土桥墩抗震性能不足,而钢管混凝土具有更好的抗震性能。钢管混凝土墩在公路、高速公路、城市快速路和高速铁路等领域具有广阔的应用前景,近年来在桥梁结构中逐步推广应用。为提高桥墩的抗震韧性,结合当前各类桥墩抗震研究现状,对方形截面钢筋混凝土墩、部分填充钢管混凝土墩、钢管混凝土墩以及端部拉筋钢管混凝土墩的极限抗震能力进行对比研究,并对钢筋混凝土、部分填充钢管混凝土、钢管混凝土与端部拉筋钢管混凝土墩的足尺有限元模型进行地震弹塑性和塑性大变形时程分析,探讨不同类型桥墩的抗震极限性能及其适用范围。分析中采用有限元软件ABAQUS建立实体–壳精细化有限元模型,模型中混凝土应力–应变关系采用参数确定性的混凝土三轴塑性–损伤模型,并引入裂缝插入技术;钢材应力–应变关系采用混合强化与韧性损伤模型,用已有单向拟静力、单向拟动力、双向拟动力和振动台加载下的钢筋混凝土、部分填充钢管混凝土、钢管混凝土与端部拉筋钢管混凝土桥墩抗震性能试验成果对有限元模型进行验证,最后采用位移响应、累积耗能和刚度损伤三个评价指标对相同造价下各类桥墩在不同地震动强度下的抗震韧性进行评价。分析结果表明:1)上述墩柱实体–壳精细化有限元模型弹塑性和塑性大变形抗震计算方法合理反映了循环荷载下钢管混凝土桥墩的滞回曲线“捏拢”效应、塑性大变形阶段承载力退化现象以及动荷载作用下的位移响应;2)当桥梁设防烈度要求为6~7度时,建议选用钢筋混凝土桥墩;当桥梁设防烈度要求为8度时,建议选用钢管混凝土桥墩;当桥梁设防烈度要求为9度及以上时,建议选用端部拉筋钢管混凝土桥墩。 展开更多
关键词 钢筋混凝土 钢管混凝土 桥墩 拉筋 抗震性能 震后刚度损伤
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钢-混凝土组合结构抗震性能研究进展 被引量:13
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作者 丁发兴 许云龙 +3 位作者 王莉萍 吕飞 段林利 余志武 《钢结构(中英文)》 2023年第12期1-26,共26页
钢-混凝土组合结构因具有抗弯刚度大、承载力高、延性好和施工便捷等优点,适应国家新型城镇化建设重大需要,在城市人口密集区域和抗震设防高烈度区域应用广泛。在提高工程结构抗震设防标准的背景下,研究钢-混凝土组合结构的抗震性能,进... 钢-混凝土组合结构因具有抗弯刚度大、承载力高、延性好和施工便捷等优点,适应国家新型城镇化建设重大需要,在城市人口密集区域和抗震设防高烈度区域应用广泛。在提高工程结构抗震设防标准的背景下,研究钢-混凝土组合结构的抗震性能,进一步提升其抗震韧性,建立具有更高韧性的钢-混凝土组合结构抗震设计方法对促进建筑结构实现“双碳”战略目标具有重要意义。为此,归纳总结了钢-混凝土组合结构抗震性能的研究进展,包括钢-混凝土组合梁、钢管混凝土柱及钢管混凝土柱-组合梁节点的滞回性能试验研究,以及钢-混凝土组合结构体系的拟静力、拟动力及振动台试验研究,讨论并比较了各种抗震分析模型及其方法,提出了当前研究存在的一些问题和尚需深入研究的方向。基于现有研究成果总结得到:1)组合梁主要依靠钢梁耗能,可采取增大钢梁截面尺寸的措施提高耗能能力。钢管混凝土柱主要依靠钢管和混凝土耗能,可采取拉筋增强约束措施直接约束混凝土,使其由脆性向塑性转变从而提高框架柱的耗能能力。与其他类型组合节点相比,刚性连接组合节点具有更好的耗能能力。2)罕遇地震下框架结构以梁耗能为主,而在超罕遇地震下仍以梁作为主要耗能部件将使工程成本大幅增加。由于超罕遇地震发生概率极低,若采取适当的增强约束措施使柱也具备耗能能力并参与耗能,则可在适当增加工程建设成本的同时使结构具有抵抗超罕遇地震的能力,此时组合结构抗震设计理念可由罕遇地震时的“强柱弱梁,梁耗能为主”向超罕遇地震时的“梁柱共同耗能”推进。3)基于平截面假定的杆系纤维模型计算软件通常适用于弹性和弹塑性小变形阶段分析,而当组合结构处于塑性大变形阶段时,结构杆件便不再符合平截面假设。对强震下组合结构体系的动力响应仿真模拟需要克服弹塑性小变形阶段的假定条件,采用适用于塑性大变形阶段结构分析的混凝土三轴弹塑性本构模型及相应的体-壳元模型是一种有效的途径。4)剪力墙结构具有整体性好、侧向刚度大等优点,但传统构造下其抗震能力较弱,可通过提升连梁和墙肢等耗能构件的耗能能力以增强结构整体耗能能力,如采用钢-混凝土组合连梁、型钢混凝土连梁或合理构造钢板连梁,以及型钢-约束混凝土或钢管混凝土墙肢等。5)工程结构在使用阶段面临着诸多灾害考验,传统方法根据不同外荷载进行独立抵抗设计,忽视了多灾害耦合作用机制,使结构综合抗灾性能难以满足使用需求,故建立安全可靠的抗多灾害设计方法和结构体系是结构工程师在防灾减灾领域的一项重大课题。 展开更多
关键词 钢-混凝土组合梁 钢管混凝土柱 钢-混凝土组合结构 抗震性能 试验研究
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智能时代的人机交互范式 被引量:28
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作者 张小龙 吕菲 程时伟 《中国科学:信息科学》 CSCD 北大核心 2018年第4期406-418,共13页
本文首先介绍范式的含义,然后讨论人机交互领域中范式这一概念的使用.以人机交互领域最有影响力的WIMP范式为例,讨论界面范式所包含的主要成分,并在此基础上分析了目前主要的智能系统的界面的特点和不足.最后本文提出了针对智能系统界... 本文首先介绍范式的含义,然后讨论人机交互领域中范式这一概念的使用.以人机交互领域最有影响力的WIMP范式为例,讨论界面范式所包含的主要成分,并在此基础上分析了目前主要的智能系统的界面的特点和不足.最后本文提出了针对智能系统界面设计的RMCP界面范式,强调智能系统界面设计需要考虑系统的角色(role)、交互模态(modal)、交互命令(commands)和信息展示方式(presentation style)这几个基本因素. 展开更多
关键词 人机交互 界面范式 智能系统
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Integrated slipper retainer mechanism to eliminate slipper wear in high-speed axial piston pumps 被引量:4
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作者 Qun CHAO Junhui ZHANG +3 位作者 Bing XU Qiannan WANG fei lyu Kun LI 《Frontiers of Mechanical Engineering》 SCIE CSCD 2022年第1期202-214,共13页
he power density of axial piston pumps can greatly benefit from increasing the speed level.However,traditional slippers in axial piston pumps are exposed to continuous sliding on the swash plate,suffering from serious... he power density of axial piston pumps can greatly benefit from increasing the speed level.However,traditional slippers in axial piston pumps are exposed to continuous sliding on the swash plate,suffering from serious wear at high rotational speeds.Therefore,this paper presents a new integrated slipper retainer mechanism for high-speed axial piston pumps,which can avoid direct contact between the slippers and the swash plate and thereby eliminate slipper wear under severe operating conditions.A lubrication model was developed for this specific slipper retainer mechanism,and experiments were carried out on a pump prototype operating at high rotational speed up to 10000 r/min.Experimental results qualitatively validated the theoretical model and confirmed the effectiveness of the new slipper design. 展开更多
关键词 axial piston pump high speed slipper wear slipper design RETAINER lubrication model
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Multi-objective optimization of surface texture for the slipper/swash plate interface in EHA pumps 被引量:1
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作者 Junhui ZHANG Yining SHEN +4 位作者 Minyao GAN Qi SU fei lyu Bing XU Yuan CHEN 《Frontiers of Mechanical Engineering》 SCIE CSCD 2022年第4期229-242,共14页
Well-designed surface textures can improve the tribological properties and the efficiency of the electro-hydrostatic actuator(EHA)pump under high-speed and high-pressure conditions.This study proposes a multi-objectiv... Well-designed surface textures can improve the tribological properties and the efficiency of the electro-hydrostatic actuator(EHA)pump under high-speed and high-pressure conditions.This study proposes a multi-objective optimization model to obtain the arbitrarily surface textures design of the slipper/swash plate interface for improving the mechanical and volumetric efficiency of the EHA pump.The model is composed of the lubrication film model,the component dynamic model considering the spinning motion,and the multi-objective optimization model.In this way,the arbitrary-shaped surface texture with the best comprehensive effect in the EHA pump is achieved and its positive effects in the EHA pump prototype are verified.Experimental results show a reduction in wear and an improvement in mechanical and volumetric efficiency by 1.4%and 0.8%,respectively,with the textured swash plate compared with the untextured one. 展开更多
关键词 electro-hydrostatic actuator axial piston pump slipper/swash plate interface multi-objective optimization surface texture
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