检索结果-南通市图书馆

高速履带车辆履带销轴橡胶衬套连接力学性能研究

在线全文

学校读者我要写书评

暂无评论

兵器装备工程学报 2024年第9期45卷 261-268页

作者：袁加乾孙飞鹰陈哲吾湖南科技大学机电工程学院江麓机电集团有限公司

针对橡胶衬套材料超弹性特性行为，设计单轴拉伸实验，获得反应销轴橡胶衬套材料的力学属性数据；选择四种常用于描述橡胶材料超弹性的本构模型，基于ABAQUS得到3阶Ogden本构模型拟合效果最优；设计橡胶衬套压缩实验与仿真压缩实验，检... 详细信息

针对橡胶衬套材料超弹性特性行为，设计单轴拉伸实验，获得反应销轴橡胶衬套材料的力学属性数据；选择四种常用于描述橡胶材料超弹性的本构模型，基于ABAQUS得到3阶Ogden本构模型拟合效果最优；设计橡胶衬套压缩实验与仿真压缩实验，检验了本构模型的合理性；建立连接结构中带有销轴和橡胶衬套的2个履带板连接有限元模型，结合橡胶衬套实际安装特点，对橡胶衬套有限元模型径向预压缩后，完成履带板拉伸和扭转仿真计算，对仿真数据进行处理，获得橡胶衬套力学性能。通过实验与仿真相结合的方式对预压缩后履带销轴橡胶衬套连接的力学性能进行了研究，得到橡胶衬套拉伸刚度50 000 N/m、扭转刚度18 600 N·mm/(°),为高速履带车辆行走系统动力学性能研究奠定基础。

关键词：橡胶衬套超弹性本构模型有限元计算预压缩力学性能

Penalty Formulations and Trap-Avoidance Strategies for Solving Hard Satisfiability Problems

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2005年第1期20卷 3-17页

作者： BenjaminW.Wah zhewu DepartmentofElectricalandComputerEngineering UniversityofIllinoisUrbanaIL61801U.S.A. OracleCorporation OneOracleDriveNashuaNH03062U.S.A.

In this paper we study the solution of SAT problems formulated as discretedecision and discrete constrained optimization problems. Constrained formulations are better thantraditional unconstrained formulations because violated constraints may provide additional forces tolead a search towards a satisfiable assignment. We summarize the theory of extended saddle pointsin penalty formulations for solving discrete constrained optimization problems and the associateddiscrete penalty method (DPM). We then examine various formulations of the objective function,choices of neighborhood in DPM, strategies for updating penalties, and heuristics for avoidingtraps. Experimental evaluations on hard benchmark instances pinpoint that traps contributesignificantly to the inefficiency of DPM and force a trajectory to repeatedly visit the same set ofor nearby points in the original variable space. To address this issue, we propose and study twotrap-avoidance strategies. The first strategy adds extra penalties on unsatisfied clauses inside atrap, leading to very large penalties for unsatisfied clauses that are trapped more often and makingthese clauses more likely to be satisfied in the future. The second strategy stores information onpoints visited before, whether inside traps or not, and avoids visiting points that are close topoints visited before. It can be implemented by modifying the penalty function in such a way that,if a trajectory gets close to points visited before, an extra penalty will take effect and force thetrajectory to a new region. It specializes to the first strategy because traps are special cases ofpoints visited before. Finally, we show experimental results on evaluating benchmarks in the DIMACSand SATLIB archives and compare our results with existing results on GSAT, WalkSAT, LSDL, andGrasp. The results demonstrate that DPM with trap avoidance is robust as well as effective forsolving hard SAT problems.

关键词： knowledge representation and reasoning techniques of algorithms constraintsatisfaction boolean satisfiability penalty formulation saddle point search

典型路谱激励下摆臂式机电馈能悬挂系统性能分析

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

兵器装备工程学报 2024年第8期45卷 51-59,145页

作者：张文广李洪周汪国胜陈哲吾湖南科技大学机电工程学院湖南湘潭411201 中国北方车辆研究所北京100072

机电馈能悬挂系统是一种新型悬挂系统,在实现装甲车辆车身减振同时回收地面传递给车身的振动能量。根据摆臂式机电馈能悬挂系统工作原理,建立了相应数学物理模型,基于Adams和AMEsim搭建了减振系统与馈能系统联合仿真模型,分析了行星变... 详细信息

机电馈能悬挂系统是一种新型悬挂系统,在实现装甲车辆车身减振同时回收地面传递给车身的振动能量。根据摆臂式机电馈能悬挂系统工作原理,建立了相应数学物理模型,基于Adams和AMEsim搭建了减振系统与馈能系统联合仿真模型,分析了行星变速器传动比、电池电阻和扭转缓冲器刚度对系统阻尼特性和馈能性能的影响。结果表明:在车速为45 km/h的铺面路、戈壁路、起伏路、砂石路4种路面工况下,车身加速度均方根值平均为4.11 m/s 2,平均馈能功率为1411.57 W,机电馈能悬挂系统有良好的减振性能和可观的馈能功率;随着行星变速器传动比增大,悬挂系统阻尼力矩和馈能功率逐渐增大,且影响显著;随着电池电阻增加,阻尼力矩和馈能功率逐渐降低;扭转缓冲器刚度变化对悬挂系统性能影响较小。

关键词：悬挂系统馈能路面谱联合仿真

Relieving the Impacts of Oral Contraceptives on Lipids Profile by Taking Pills in a Novel Scheme

在线全文

学校读者我要写书评

暂无评论

Journal of Reproduction and Contraception 2003年第1期14卷 21-30页

作者： Pei-juanYANG Si-tianLIU Xue-zhewu E-xiangZHENG ShanghaiInstituteofPlannedParenthoodResearch Shanghai200032China ShanghaiFirstMaternityChildHealthHospital Shanghai200040China

Objective To explore whether the changes on lipids profile induced by oral contraceptives could be reduced through alternatively administering two oral contraceptives of different formulations (either predominant in progestogen or estrogen) Materials &. Methods A total of 59 women aged 25- 45 were divided into two treatment *** subjects in Group A received oral contraceptive A (Oc A: NET 0. 600 mg + EE 0. 035 mg) and B (OcB: LNG 0. 15mg + EEO. 03 mg) alternatively during 12 treatment cycles. Each contraceptive was administrated for three cycles consecutively with starting from OcA. The subjects in the B group received OcB only during 12 treatment cycles. Fasting blood were drawn before treatment, at the end of each trimester treatment and at the end of one cycle after stopping treatment respectively. The concentrations of lipids and apolipoproteins were measured.Results OcA increased the levels of triglyceride(TG) , total cholesterol (TC), high density lipoprotein-cholesterol(HDL-c) , and apolipoprotein AI (apo AI) with statistical significance, whereas OcB significantly decreased all parameters above. As compared with the control group, the overall mean of variation in the study group was much less than that of the control group.Conclusion It indicates that the impacts of oral contraceptives on lipids profile could be moderated by means of alternatively administering Ocs of two different formulations , with estrogen-dominant or progestogen-dominant.

关键词： oral contraceptive lipid apolipoprotein progestogen estrogen impact

Relationship between the development of sphenoid bone in human embryo and fetus and adult morphology

在线全文

学校读者我要写书评

暂无评论

Relationship between the development of sphenoid bone in hum...

Histological study of fabella and muscle origin of the plantaris and gastrocnemius lateral head in late-stage fetuses

中国解剖学会2021年年会

作者： Shaohe Wang Zhao Peng Jin zhewu Gen Murakam Department of Anatomy Wuxi School of MedicineJiangnan University Division of Internal Medicine Cupid-Fair Clinic

The developing sphenoid bone is considered to be a median cartilage mass (basilar sphenoid bone) with three cartilaginous processes (orbital wing or orbital pterygoid process, temporal wing and nasal pterygoid process).The relationship between this initial morphology and adult morphology is difficult to determine because of extensive membranous ossification along the cartilaginous elements.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Histological study of fabella and muscle origin of the plant...

Nine-month Angiographic and Two-year Clinical Follow-up of Novel Biodegradable-polymer Arsenic Trioxide-eluting Stent Versus Durable-polymer Sirolimus-eluting Stent For Coronary Artery Disease

中国解剖学会2021年年会

作者： Huang Shu Du Bin Jin zhewu Gen Murakam Department of Anatomy Wuxi School of MedicineJiangnan University Division of Internal Medicine Cupid-Fair Clinic

Cartilaginous fabella appears to be embedded in the plantaris origin (PL) that fuses with the gastrocnemius lateral head (GL) in midterm *** sections of unilateral knee joints of 15 latestage fetuses, we reexamined the topographical anatomy of fabella or its analogue (a tight fibrous mass) with origins of the GL and *** of whether the cartilaginous fabella is present (6/15) or absent,these muscle origins were composed of three parts (PL1,PL2 and PL3

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Medical Journal 2015年第6期128卷 768-773页

作者： Li Shen Wei Yang Jia-Sheng Yin Xue-Bo Liu Yi-zhewu Ai-Jun Sun Ju-Ying Qian Jun-Bo Ge Department of Cardiology Shanghai Institute of Cardiovascular Diseases Zhongshan Hospital Fudan University Shanghai 200032 China Department of Cardiology First Affiliated Hospital of Harbin Medical University Harbin Heilongjiang 150001 China Department of Cardiology East Hospital Tongji University School of Medicine Shanghai 200120 China

Background:Despite great reduction of in-stent restenosis,first-generation drug-eluting stents (DESs) have increased the risk of late stent thrombosis due to delayed *** trioxide,a natural substance that could inhibit cell proliferation and induce cell apoptosis,seems to be a promising surrogate of sirolimus to improve DES *** randomized controlled trial was to evaluate the efficacy and safety of a novel arsenic trioxide-eluting stent (AES),compared with traditional sirolimus-eluting stent (SES).Methods:Patients with symptoms of angina pectoris were enrolled and randomized to AES or SES *** primary endpoint was target vessel failure (TVF),and the second endpoint includes rates of all-cause death,cardiac death or myocardial infarction,target lesion revascularization (TLR) by telephone visit and late luminal loss (LLL) at 9-month by angiographic ***:From July 2007 to 2009,212 patients were enrolled and randomized 1 ∶1 to receive either AES or *** 2 years of follow-up,TVF rate was similar between AES and SES group (6.67％ vs.5.83％,P =0.980).Frequency of all-cause death was significantly lower in AES group (0 vs.4.85％,P =0.028).There was no significant difference between AES and SES in frequency of TLR and in-stent restenosis,but greater in-stent LLL was observed for AES group (0.29 ± 0.52 mm vs.0.1 0 ± 0.25 mm,P =0.008).Conclusions:After 2 years of follow-up,AES demonstrated comparable efficacy and safety to SES for the treatment of de novo coronary artery lesions.

关键词： Arsenic Trioxide Coronary Artery Disease Drug-eluting Stent

在线全文

学校读者我要写书评

暂无评论

环形绕组无刷直流电机的混合换向方法

电工技术学报 2022年第17期37卷 4346-4354页

作者：张庆湖贾喆武王东海军工程大学舰船综合电力技术国防科技重点实验室武汉430033 海军研究院北京102401

环形绕组无刷直流电机(CWBLDCM)是一种新型的多相非正弦永磁电机,其转矩性能与绕组电流换向过程密切相关。该文提出了一种利用绕组自身反电动势和母线电压来改善电机转矩性能的混合换向方法,该方法有两个换向控制参数(β,γ),随着控制... 详细信息

环形绕组无刷直流电机(CWBLDCM)是一种新型的多相非正弦永磁电机,其转矩性能与绕组电流换向过程密切相关。该文提出了一种利用绕组自身反电动势和母线电压来改善电机转矩性能的混合换向方法,该方法有两个换向控制参数(β,γ),随着控制参数的变化,换向过程可能呈现出四种典型的换向状态。首先对各换向状态进行了分析、仿真和实验验证;然后比较了不同换向状态下的转矩性能;最后根据比较结果,提出了一种针对CWBLDC电机转矩性能的优化控制策略。

关键词：无刷直流电机换向方法转矩密度转矩脉动

Effect of Mifepristone on Transforming Growth Factor -βand its Receptor Transcription in Decidua, Villi and Serum Tumor Necrosis Factor -α Level in Early Human Gestation

在线全文

学校读者我要写书评

暂无评论

Journal of Reproduction and Contraception 2004年第1期15卷 33-38页

作者： Li-pingJIN Da-jinLI Jing-yuSHAO Song-guoZHENG Xue-zhewu LaboratoryofReproductiveImmunology InstituteofObstetricsandGynecologyFudanUniversityShanghai200011China ShanghaiFirstMaternity＆InfantHealthHospital Shanghai200040China LaboratoryofMolecularBiology TumorHospitalFudanUniversityShanghai200032China

Objective To investigate the role of mifepristone in regulating cytokines of materno-fetal interface and serum of human early gestationMethods Thirty-five women with early pregnancy received mifepristone 50 mg orallyon study d 1 and d 2, respectively, followed by undergoing artificial abortion to getdecidua and villi on study d 3. Twenty-five women with early pregnancy withoutmifepristone administration as control also underwent artificial abortion to get de-cidua and villi. The expressions of TGF-β1 and TGF-β1 receptor mRNA in the earlydecidua and villi were assessed by using RT-PCR . The concentrations of serum TNF-α were measured by *** The decidual expressions of TGF- β1 mRNA and TGF-β1 receptor mRNA in thetreated group were significantly lower than those of the control (P0.05). The serum TNF-β1 levelselevated significantly after mifepristone *** The antigestational effect of mifepristone might act through suppressingthe transcription of TGF-β1 and TGF-β1 receptor in the decidua and increasing theserum TNF-α level, which interfered in the materno-fetal interface Th2 bias.

关键词： Mifepristone deciduas villi transforming growth factor-β tumor necrosis factor-α