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DEM investigation of strength and critical state behaviours of granular materials under true triaxial loadings

Particuology 2024年第2期85卷 198-212页

作者： minyi zhu Guobin Gong Jun Xia Stephen Wilkinson Department of Civil Engineering Xi'an Jiaotong-Liverpool UniversityChina Department of Civil Engineering and Industrial Design University of LiverpoolLiverpoolUK Faculty of Engineering and Information Sciences University of Wollongong in DubaiUnited Arab Emirates

This paper investigates the strength and critical state(CS)behaviours of granular materials via DEM simulations of true triaxial drained tests under three different loading modes including constant b(in-termediate stress ratio)tests with constantσ'1(major principal stress),constant p(mean pressure)and constantσ'3(minor principal stress)*** this end,a series of samples are generated with the same particle size distribution,and with the confining stresses ranging from 100 kPa to 900 *** CS is achieved for all *** the macroscopic behaviours and the microscopic behaviours are examined and compared considering different loading modes,confining stresses and intermediate stress ratios(b).The critical state lines(CSLs)are found to be unique and independent of the loading modes,but dependent on the b *** CSLs with b=0 and b=1 form the two boundaries of CSLs respectively beyond which CSLs under all other b tests cannot go *** different strength criteria are examined and compared in terms of both peak and CS *** Mohr-Coulomb strength criterion is found to be only suitable for axisymmetric loading *** Lade-Duncan criterion is only suitable for describing peak strengths,which is dependent on the loading modes and confining *** Satake criterion and Matsuoka-Nakai criterion are the more appropriate strength criteria for describing CS failures,indicating that the CS values of both the Satake parameter and the Matsuoka-Nakai parameter describe an inherent property that characterizes the CS failure for a given type of *** CS mechanical coordination number is fitted by a curved line for a given b value,which is unique regardless of the loading *** peak and CS values of both major and minor principal fabric tensors decrease with increasing b values,while they increase with increasing b values for the intermediate principal fabric tensor.

关键词： Discrete element method Intermediate stress ratio Dilation Critical state Failure criterion

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Curve Optimization of Tapered Cantilever Beams Under Tip Loads

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Advances in Applied Mathematics and Mechanics 2021年第6期13卷 1485-1500页

作者： minyi zhu Guobin Gong Jun Xia Department of Civil Engineering Xi’an Jiaotong—Liverpool UniversitySuzhouJiangsu 215123China

The study adopts the variational method for analyzing the cantilever tapered beams under a tip load as well as a definite end displacement,and further determining the optimized shapes and materials that can minimize the *** types of beams are taken into account,i.e.,the Euler-Bernoulli beam without considering shear deformation and the Timoshenko beam with shear *** using the energy theorem and the reference of isoperimetric problem,the width variation curves and the corresponding minimum masses are derived for both beam *** optimized curve of beam width for the Euler-Bernoulli beam is found to be a linear function,but nonlinear for the Timoshenko *** is also found that the optimized curve in the Timoshenko beam case starts from non-zero at the tip end,but its tendency gradually approaches the one of the Euler-Bernoulli *** results indicate that with the increase of the Poisson’s ratio,the required minimum mass of the beam will increase no matter how the material changes,suggesting that the optimized mass for the case of Euler-Bernoulli beam is the lower boundary limit which the Timoshenko case cannot go ***,the ratio r/E(density against Elastic Modulus)of the material should be as small as possible,while the ratio h2/L4 of the beam should be as large as possible in order to minimize the mass for the case of Euler-Bernoulli beam,of which the conclusion is extended to be applicable for the case of Timoshenko *** addition,the optimized curves for Euler-Bernoulli beam types are all found to be power functions of length for both tip point load cases and uniform load cases.

关键词： Tapered beam Euler-Bernoulli beam Timoshenko beam variational principle isoperimetric problem curve optimization

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血运重建治疗对伴慢性多血管病变的急性肠系膜缺血导致的短肠综合征患者肠康复治疗效果的影响

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中华普通外科杂志 2024年第3期39卷 172-182页

作者：夏宇飞齐欣朱旻怡高学金章黎孙羽东王新颖东南大学医学院南京210009 南京大学医学院附属金陵医院全军普通外科研究所南京210002

目的探索伴慢性多血管病变的急性肠系膜缺血(acute mesenteric ischemia,AMI)导致的短肠综合征(short bowel syndrome,SBS)患者在肠康复治疗(intestinal rehabilitation therapy,IRT)前接受血运重建治疗能否优化IRT的疗效。方法回顾性分析2012年1月至2023年10月期间在中国人民解放军东部战区总医院诊断由伴慢性多血管病变的AMI导致SBS并接受IRT的住院患者18例的临床资料。结果在IRT后,血运重建组的四肢骨骼肌指数和握力的增加量显著高于对照组,分别为[(0.28±0.26)kg/m^(2)比(0.02±0.21)kg/m^(2),P=0.033]和[(0.97±0.33)kg比(0.48±0.34)kg,P=0.007]。同样,血运重建组肠内营养(EN)摄入量的增加量显著高于对照组[(572.5±93.6)ml/d比(375.2±176.3)ml/d,P=0.012],并伴随着肠道氮吸收率更高的提升[(25.06±14.06)%比(13.84±4.62)%,P=0.034]和肠道症状评定量表评分更大幅度的降低[(-15.88±3.94)分比(-6.33±5.13)分,P=0.030],且两组EN制剂类型的组成在IRT后也有显著差异(P=0.046)。此外,血运重建组出院时的简明健康量表(SF-36)在躯体疼痛(BP)、总体健康(GH)、活力(VT)、社会功能(SF)、精神健康(MH)等五项指标的得分上显著高于对照组(P<0.05)。结论由伴慢性多血管病变的AMI导致SBS的患者接受血运重建治疗不能使其在IRT中获得体重和血液学营养指标上更高的增长,但有利于患者改善肌肉功能、改善EN吸收、提高摆脱肠外营养的机会、缓解胃肠道症状并提高生活质量。

关键词：肠系膜缺血短肠综合征康复研究血运重建

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Highly adaptive and broadband triboelectric energy harvester with stretching silicone rubber strip for variable harmonic frequency vibration

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Nano Research 2024年第5期17卷 4089-4099页

作者： Taili Du Dianlong Shen Ziyue Xi Hongyong Yu Fangyang Dong Cong Zhao Meixian zhu Yongjiu Zou Peiting Sun minyi Xu Dalian Key Laboratory of Marine Micro/Nano Energy and Self-powered Systems Marine Engineering CollegeDalian Maritime UniversityDalian 116026China Collaborative Innovation Research Institute of Autonomous Ship Dalian Maritime UniversityDalian 116026China

An enormous number of wireless sensing nodes(WSNs)are of great significance for the Internet of Things(IoT).It is tremendously prospective to realize the in-situ power supply of WSNs by harvesting unutilized mechanical vibration energy.A harmonic silicone rubber triboelectric nanogenerator(HSR-TENG)is developed focusing on ubiquitous constant working frequency *** unique design of the strip serving as a flexible resonator realizes both soft contact and high and broadband *** significant factors influencing the 1^(st)-order vibration mode of the strip are developed for realizing the harmonic frequency adaptation to external *** surface treatment of the strip improves the output performance of HSR-TENG by 49.1%as well as eliminates the adhesion *** HSR-TENG is able to achieve a voltage output bandwidth of 19 Hz under a vibration strength of 3.0,showing its broadband *** peak power density of 153.9 W/m^(3)is achieved and 12×0.5 W light-emitting diodes(LEDs)are successfully illuminated by the *** can continuously power a temperature sensor by harvesting the actual compressor vibration *** brief,the HSR-TENG provides a promising way for constant frequency vibration energy harvesting,so as to achieve in-situ power supply for the WSNs in the vicinity.

关键词： vibration energy harvesting triboelectric nanogenerator flexible silicone rubber strip harmonic vibration broadband

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同步器齿套倒锥齿塑性成形的工艺分析

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制造技术与机床 2010年第5期 25-27页

作者：朱民益上海汽车变速器有限公司上海201800

通过对同步器齿套倒锥齿加工技术的分析,从塑性成形的工作原理,设计与试制须注意事项等方面,介绍了一种新的同步器齿套倒锥齿加工的塑性成形法。

关键词：同步器齿套倒锥挤压

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试论黄宗羲经世致用的史学思想

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科教文汇 2011年第20期 70-71页

作者：朱敏仪华南师范大学历史文化学院广东广州510630

明末清初,社会动乱,但在文化上却出现了经世致用的思潮。思想界随即掀起了狂涛巨澜,涌现了许多先进的人物,而黄宗羲就是经学致用思想的佼佼者。本文试从治学、著述、创新等方面对黄宗羲经世致用的史学思想进行论述,以进一步深入认识和... 详细信息

明末清初,社会动乱,但在文化上却出现了经世致用的思潮。思想界随即掀起了狂涛巨澜,涌现了许多先进的人物,而黄宗羲就是经学致用思想的佼佼者。本文试从治学、著述、创新等方面对黄宗羲经世致用的史学思想进行论述,以进一步深入认识和研究黄宗羲的治学风范和史学思想。

关键词：黄宗羲经世致用史学思想

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两种治疗化疗性静脉炎方法的效果比较

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全科护理 2010年第32期8卷 2923-2924页

作者：朱敏怡广州医学院附属肿瘤医院

[目的]比较化疗性静脉炎两种防治方法的效果。[方法]选择50例以外周静脉穿刺行化疗所致静脉炎的病人。随机分为两组,对照组25例采用常规利多卡因液局部封闭+硫酸镁湿敷,观察组25例采用利肤宁(放射治疗皮肤防护剂)外用涂擦。观察并比较... 详细信息

[目的]比较化疗性静脉炎两种防治方法的效果。[方法]选择50例以外周静脉穿刺行化疗所致静脉炎的病人。随机分为两组,对照组25例采用常规利多卡因液局部封闭+硫酸镁湿敷,观察组25例采用利肤宁(放射治疗皮肤防护剂)外用涂擦。观察并比较两组治疗效果。[结果]观察组、对照组有效率分别为92%、68%,经比较差异有统计学意义(P<0.05)。[结论]用皮肤防护剂利肤宁涂擦治疗化疗性静脉炎有较好的效果。

关键词：化疗性静脉炎利肤宁利多卡因硫酸镁护理

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我国上市公司股权结构与公司绩效的实证分析

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西部金融 2013年第7期 46-48,57页

作者：朱敏怡上海交通大学安泰经济与管理学院上海200240

股权结构因素与公司绩效的量化研究是分析两者关系的关键。本文在论述国内外学者对于二者之间关系的研究基础之上,以2011年的2111家上市公司作为研究对象,通过实证研究的方法,分析得出境内发起人股比例与公司绩效具有显著的正相关关系,... 详细信息

股权结构因素与公司绩效的量化研究是分析两者关系的关键。本文在论述国内外学者对于二者之间关系的研究基础之上,以2011年的2111家上市公司作为研究对象,通过实证研究的方法,分析得出境内发起人股比例与公司绩效具有显著的正相关关系,A股流通股比例与公司绩效具有显著的负相关关系,而国有股比例与外资股比例与公司绩效之间无显著相关关系。

关键词：上市公司公司绩效股权结构

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