检索结果-南通市图书馆

初应力状态下夹芯复合材料曲梁面板的局部振动的理论分析(英文)

在线全文

学校读者我要写书评

暂无评论

船舶力学 2007年第6期11卷 942-952页

作者：王玮波 r.a.shenoi 中国船舶科学研究中心 School of Engineering Sciences University of SouthamptonSO17 1BJUK

在船舶领域,以复合材料层合面板及泡沫芯材组成的夹芯复合材料板梁结构已大量应用在游艇及复合材料高速艇上。文章研究了受初始静载荷作用下夹芯复合材料曲梁的面板的局部自由振动问题,并给出一种相应的理论分析方法。文中通过将芯材简... 详细信息

在船舶领域,以复合材料层合面板及泡沫芯材组成的夹芯复合材料板梁结构已大量应用在游艇及复合材料高速艇上。文章研究了受初始静载荷作用下夹芯复合材料曲梁的面板的局部自由振动问题,并给出一种相应的理论分析方法。文中通过将芯材简化为Winkler弹性地基,将面板简化为一复合材料曲梁,从而使所研究问题蜕化为有初始静载荷作用下弹性地基上任意曲梁的固有振动问题。在局部振动位移是基于初始静载平衡位置并与初始位移相比是小量的假定的基础上,根据能量原理推导出面板的运动方程。研究的结果表明,该面板的局部振动不只取决于面板的弯曲刚度和长度,以及芯材的弹性刚度,也在很大程度上取决于梁的曲率及面板所受到的初始轴向压力。

关键词：复合材料夹芯曲梁局部自由振动

合拢弯矩作用下复合材料曲梁突变屈曲的研究(英文)

在线全文

学校读者我要写书评

暂无评论

船舶力学 2006年第6期10卷 102-114页

作者：王玮波 r.a.shenoi 崔维成 School of Engineering Sciences University of Southampton 中国船舶科学研究中心江苏无锡214082

研究了复合材料曲梁在受到合拢弯矩作用下发生的屈曲情况,并给出一种理论解析方法来分析这种很可能发生在复合材料弯曲结构中的脱层耦合屈曲问题。该方法是基于曲梁大变形理论及断裂力学而提出来的。文中并用该解析方法分析了一个特定... 详细信息

研究了复合材料曲梁在受到合拢弯矩作用下发生的屈曲情况,并给出一种理论解析方法来分析这种很可能发生在复合材料弯曲结构中的脱层耦合屈曲问题。该方法是基于曲梁大变形理论及断裂力学而提出来的。文中并用该解析方法分析了一个特定的常见的情况,在该题例中脱层发生在非常靠近内表面处并且突变屈曲就发生在该薄脱层。在文中也对脱层裂纹的弧角对极限载荷的影响进行了研究。

关键词：复合材料曲梁脱层损伤断裂突变屈曲应变能

单向复合材料高应变率下材料特性的研究(英文)

在线全文

学校读者我要写书评

暂无评论

船舶力学 2009年第3期13卷 406-415页

作者：王玮波 r. A. shenoi 中国船舶科学研究中心江苏无锡214082 School of Engineering Sciences University of SouthamptonSO171BJUK

在船舶领域,复合材料及夹芯复合材料板梁结构已大量应用在舰船结构中,尤其游艇及复合材料高速艇上。在运行过程中,这些结构有时很可能会受到如砰击、碰撞等动态载荷或高速冲击载荷。然而到目前为止,大多数的结构设计所用到的材料特性仍... 详细信息

在船舶领域,复合材料及夹芯复合材料板梁结构已大量应用在舰船结构中,尤其游艇及复合材料高速艇上。在运行过程中,这些结构有时很可能会受到如砰击、碰撞等动态载荷或高速冲击载荷。然而到目前为止,大多数的结构设计所用到的材料特性仍基于低应变率情况下的准静态测试结果。该文研究了高速艇等结构中的纤维增强复合材料高应变率情况下的材料特性,通过引入一种粘弹性模型来模拟并分析研究对象。并在世界先进的INSTrON高应变率材料试验机上设计并完成了相关试验,验证了该粘弹性模型、确定了模型中的材料参数。该粘弹性模型然后被用来研究分析应变率对单向复合材料机械特性的影响。

关键词：船舶结构纤维增强复合材料强度变形动态载荷高应变率特性

Analysis and Optimization of Operational and Pollutant Attributes of Diesel Engine with CNT-Infused Orange Peel Biodiesel-Diesel Blend Fuel

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第2期33卷 761-778页

作者： ranjeet rAI r.r.SAHOO Mechanical Engineering Department GLA UniversityMathura281406India Mechanical Engineering Department IIT(BHU)Varanasi221005India

The current study is performed to find sustainable solutions for the future of transportation and environmental well-being.Both conventional methods and experimental design table(L16 Orthogonal Array)techniques have been employed to examine and optimize a diesel-powered engine's operational and pollutant parameters.The L16 Orthogonal Array is obtained through Taguchi's experimental design approach using Minitab 16 software.The experimental design incorporated three control variables,namely engine speed,fuel type,and engine load,each with four levels.The operational parameters,namely brake thermal efficiency(BTE)and brake specific fuel consumption(BSFC),as well as the emission characteristics,including hydrocarbon(HC),carbon monoxide(CO),nitrogen oxide(NO),and smoke emissions,were acquired using the L16 orthogonal array(OA) and subsequently examined.The utilization of methodologies such as signal-to-noise(S/N) ratio and grey analysis was employed to determine the optimal operational state of the engine to achieve maximum performance while minimizing emissions.The engine's ideal state of operation,in terms of BTE and BSFC,was determined to be at 75% engine load,1000 r/min engine speed,and using 10^(-4)(in vol) carbon nanotube incorporated 20% orange peel biodiesel(OPB20CNT100) blended fuel(A3-B1-C4).The study indicated that engine load significantly influenced BTE and BSFC,with 84.05% and 87.79% contribution factors,respectively.At 25% engine load,1000 r/min,and OPB20CNT100 fuel(A1-B1-C4) CO,smoke,NO,and HC emissions were the lowest.Engine load affects emissions the most.Engine BSFC increased 3.10% and NO emissions 1.77%.BTE,CO,smoke,and HC emissions decreased by 1.9%,12.29%,47.05%,and 47.22%,respectively,at optimal operating conditions concerning diesel fuel.This study shows that Taguchi-Grey's experimental design optimizes diesel engine operational and pollutant attributes.The outcomes revealed that orange peel biodiesel infused with CNT can replace diesel fuel in an environmentally friendly way.This alternative

关键词： Taguchi-Grey method OPB20CNT100 transesterification S/N ratio GrG HC CO and NO

Treat to target in Crohn’s disease:A practical guide for clinicians

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第1期30卷 50-69页

作者： Ashish r Srinivasan Department of Gastroenterology Austin HealthVictoriaMelbourne 3083Australia Department of Gastroenterology Eastern HealthVictoriaMelbourne 3128Australia Department of Medicine University of MelbourneVictoriaMelbourne 3052Australia

A treat-to-target(T2T)approach applies the principles of early intervention and tight disease control to optimise long-term outcomes in Crohn's disease.The Selecting Therapeutic Targets in Inflammatory Bowel Disease(STrIDE)-II guidelines specify short,intermediate,and long-term treatment goals,documenting specific treatment targets to be achieved at each of these timepoints.Scheduled appraisal of Crohn’s disease activity against pre-defined treatment targets at these timepoints remains central to determining whether current therapy should be continued or modified.Consensus treatment targets in Crohn’s disease comprise combination clinical and patient-reported outcome remission,in conjunction with biomarker normalisation and endoscopic healing.Although the STrIDE-II guidelines endorse the pursuit of endoscopic healing,clinicians must consider that this may not always be appropriate,acceptable,or achievable in all patients.This underscores the need to engage patients at the outset in an effort to personalise care and individualise treatment targets.The use of non-invasive biomarkers such as faecal calprotectin in conjunction with cross-sectional imaging techniques,particularly intestinal ultrasound,holds great promise;as do emerging treatment targets such as transmural healing.Two randomised clinical trials,namely,CALM and STArDUST,have evaluated the efficacy of a T2T approach in achieving endoscopic endpoints in patients with Crohn’s disease.Findings from these studies reflect that patient subgroups and Crohn’s disease characteristics likely to benefit most from a T2T approach,remain to be clarified.Moreover,outside of clinical trials,data pertaining to the real-world effectiveness of a T2T approach remains scare,highlighting the need for pragmatic real-world studies.Despite the obvious promise of a T2T approach,a lack of guidance to support its integration into real-world clinical practice has the potential to limit its uptake.This highlights the need to describe strategies,processes,and models of care capable of

关键词： Treat to target Inflammatory bowel disease Crohn’s disease Treatment targets Endoscopic remission Transmural healing Time to response Intestinal ultrasound

Kinematic analysis of flexible bipedal robotic systems

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

Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 795-818页

作者： r.FAZEL A.M.SHAFEI S.r.NEKOO Department of Mechanical Engineering Shahid Bahonar University of KermanKerman ***Iran Departamento de Ingenieria de Sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous researchers.What distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic systems.This is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases considerably.Moreover,the human leg bones that are involved in walking are supported by viscoelastic muscles and ligaments.Therefore,for achieving more exact results,it is essential to model the robot links with viscoelastic properties.To this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of motion.The most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational force.The extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned goal.To overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue problem.By solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are determined.The effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of robotic systems are also studied.The findings o

关键词： bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient

Neurogenic potential of NG2 in neurotrauma:a systematic review

在线全文

学校读者我要写书评

暂无评论

Neural regeneration research 2024年第12期19卷 2673-2683页

作者： Yuri r.rigo radharani Benvenutti Luis V.Portela Nathan r.Strogulski Departamento de Bioquímica Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do Sul(UFRGS)Porto AlegreBrazil School of Pharmacy and Biomolecular Sciences RCSI University of Medicine and Health SciencesDublinIreland School of Biochemistry and Immunology Trinity Biomedical Sciences InstituteTrinity College DublinUniversity of DublinDublinIreland

regenerative approaches towards neuronal loss following traumatic brain or spinal cord injury have long been considered a dogma in neuroscience and remain a cutting-edge area of research.This is reflected in a large disparity between the number of studies investigating primary and secondary injury as therapeutic to rgets in spinal co rd and traumatic brain injuries.Significant advances in biotechnology may have the potential to reshape the current state-of-the-art and bring focus to primary injury neurotrauma research.recent studies using neural-glial factor/antigen 2(NG2)cells indicate that they may differentiate into neurons even in the developed brain.As these cells show great potential to play a regenerative role,studies have been conducted to test various manipulations in neurotrauma models aimed at eliciting a neurogenic response from them.In the present study,we systematically reviewed the experimental protocols and findings described in the scientific literature,which were peer-reviewed original research articles(1)describing preclinical experimental studies,(2)investigating NG2 cells,(3)associated with neurogenesis and neurotrauma,and(4)in vitro and/or in vivo,available in PubMed/MEDLINE,Web of Science or SCOPUS,from 1998 to 2022.Here,we have reviewed a total of 1504 papers,and summarized findings that ultimately suggest that NG2 cells possess an inducible neurogenic potential in animal models and in vitro.We also discriminate findings of NG2 neurogenesis promoted by different pharmacological and genetic approaches over functional and biochemical outcomes of traumatic brain injury and spinal co rd injury models,and provide mounting evidence for the potential benefits of manipulated NG2 cell ex vivo transplantation in primary injury treatment.These findings indicate the feasibility of NG2 cell neurogenesis strategies and add new players in the development of therapeutic alternatives for neurotrauma.

关键词： neural-glial antigen 2 neural-glial factor 2 neuron differentiation NG2 cell regeneration spinal cord injury(SCI) traumatic brain injury(TBI)

Transcranial photobiomodulation for the brain: a wide range of clinical applications

在线全文

学校读者我要写书评

暂无评论

Neural regeneration research 2024年第3期19卷 483-484页

作者： Michael r.Hamblin Laser research Centre Faculty of Health ScienceUniversity of Johannesburg-Doornfontein CampusDoornfonteinSouth Africa

Photobiomodulation therapy(PBMT)is a rapidly growing approach to the healing,stimulation,protection,and regeneration of many human organs and tissue types.PBMT started in the 1960s as low-level laser therapy for wound healing,but since then the introduction of light-emitting diodes(LEDs)has dramatically increased the number of applications and reports of positive results.PBMT generally uses red(620-700 nm)and/or near-infrared(780-1270 nm)wavelengths of light at an intensity that causes no tissue heating,and its activity is based on well-established biological and cellular mechanisms(de Freitas and Hamblin,2016).While laser therapists continue to use various types of laser in their office practice,LEDs are ideally suited for home use devices because they are completely safe and without any known significant adverse effects.Among the various body parts on which PBMT has been shown to exert beneficial effects,the brain stands out as perhaps the most promising overall.PBMT has been shown to reduce neuroinflammation,while increasing mitochondrial function,oxygen consumption,and blood flow within the brain(Hamblin,2016).Moreover,PBMT can stimulate the processes of synaptogenesis,neurogenesis,and neuroplasticity thus helping the brain to heal itself.

关键词： healing stimulation wound

Holographic dark energy in non-conserved gravity theory

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： H r Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

recently,reconsidering the rastall ideaT■=a,_(μ) through relativistic thermodynamics gives a new form for the scalar field which led us to construct modern modified theory of gravity debugged'non-conserved gravity theory'Fazlollahi 2023 Euro.Phys.J.C 83923.This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy.Hence,in this study we have reinvestigated holographic dark energy in the non-conserved theory of gravity.In this context,the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field.As shown,due to non-conservation effects on large-scale structures,unlike the original holographic model,our model onsets an acceleration epoch for the current Universe satisfies observations.Moreover,the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy