检索结果-南通市图书馆

Kinematic analysis of flexible bipedal robotic systems

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 *** distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic *** 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 ***,the human leg bones that are involved in walking are supported by viscoelastic muscles and ***,for achieving more exact results,it is essential to model the robot links with viscoelastic *** 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 *** 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 *** 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 *** 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 *** solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are *** 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

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

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Blood metal concentrations and cardiac structure and function in total joint arthroplasty patients

引用

World journal of Orthopedics 2024年第8期15卷 773-782页

作者： Peter c Brennan stephanie m Peterson Thomas j O'Byrne mariana L Laporta cody c Wyles Paul j jannetto garvan c Kane maria Vassilaki Hilal maradit Kremers Department of Orthopedic surgery Mayo ClinicRochesterMN 55905United States Department of Quantitative Health sciences Mayo ClinicRochesterMN 55905United States Department of Anesthesiology and Perioperative medicine Mayo ClinicRochesterMN 55905United States Department of Laboratory medicine and Pathology Mayo ClinicRochesterMN 55905United States Department of cardiovascular Diseases Mayo ClinicRochesterMN 55905United States

BAcKgROUND There is concern regarding potential long-term cardiotoxicity with systemic distribution of metals in total joint arthroplasty(TjA)*** To determine the association of commonly used implant metals with echocardiographic measures in TjA *** The study comprised 110 TjA patients who had a recent history of high chromium,cobalt or titanium *** underwent two-dimensional,three-dimensional,Doppler and speckle-strain transthoracic echocardiography and a blood draw to measure metal *** and sex-adjusted linear and logistic regression models were used to examine the association of metal concentrations(exposure)with echocardiographic measures(outcome).REsULTs Higher cobalt concentrations were associated with increased left ventricular end-diastolic volume(estimate 5.09;95%cI:0.02-10.17)as well as left atrial and right ventricular dilation,particularly in men but no changes in cardiac *** titanium concentrations were associated with a reduction in left ventricle global longitudinal strain(estimate 0.38;95%cI:0.70 to 0.06)and cardiac index(estimate 0.08;95%cI,-0.15 to-0.01).cONcLUsION Elevated cobalt and titanium concentrations may be associated with structural and functional cardiac changes in some *** studies are warranted to better understand the systemic effects of metals in TjA patients.

关键词： Total joint arthroplasty metal-on-metal cardiotoxicity Heart failure Echocardiography cobalt

来源：

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

Evaluation of the seismic behavior of reinforced concrete structures with flat slab-column gravity frame and shear walls through nonlinear analysis methods

引用

Earthquake Engineering and Engineering Vibration 2024年第3期23卷 713-726页

作者： m.A.Najafgholipour s.Heidarian Radbakhsh E.Erfani Department of civil and Environmental Engineering Shiraz University of TechnologyShiraz ***Iran Department of Building Civiland Environmental EngineeringConcordia UniversityMontréal H3G 1M8Canada

This paper presents an investigation of the seismic behavior of reinforced concrete(Rc)structures in which shear walls are the main lateral load-resisting elements and the participation of flat slab floor systems is not considered in the seismic design *** this regard,the behavior of six prototype structures(with different heights and plan layouts)is investigated through nonlinear static and time history analyses,implemented in the Opensees *** results of the analyses are presented in terms of the behavior of the slab-column connections and their mode of failure at different loading ***,the global response of the buildings is discussed in terms of some parameters,such as lateral overstrength due to the gravity flat slab-column *** to the nonlinear static analyses,in structures in which the slab-column connections were designed only for gravity loads,the slab-column connections exhibited a punching mode of failure even in the early stages of ***,the punching failure was eliminated in structures in which a minimum transverse reinforcement recommended in AcI 318(2019)was provided in the slabs at joint ***,despite neglecting the contribution of gravity flat slab-column frames in the lateral load resistance of the structures,a relatively significant overstrength was imposed on the structures by the gravity frames.

关键词： Rc flat slab-column frames seismic behavior nonlinear analysis time history analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Deciding on life-saving treatment after a violent suicide attempt:an ethical case report

引用

general Psychiatry 2024年第2期37卷 289-291页

作者： Robert Wichers Hanna m Heller sisco van Veen Department of child and Adolescent Psychiatry&Psychosocial care Amsterdam University Medical CenterLocation AMCAmsterdamThe Netherlands Amsterdam Public Health Mental Health programAmsterdamThe Netherlands Department of Hospital Psychiatry Amsterdam University Medical CenterLocation VUmcAmsterdamThe Netherlands Research Department 113 Suicide PreventionAmsterdamThe Netherlands Department of Psychiatry&Department of Ethics Law and HumanitiesAmsterdam University Medical CenterAmsterdamThe Netherlands ggZ ingeest mental Health care AmsterdamThe Netherlands

To the editor:In the UsA alone,there were 1.7 million suicide attempts in 2021.1 Although the majority of suicide attempts are not fatal,immediate medical attention is often necessary,especially when violent methods are used.2 These methods include jumping from heights,using a firearm,crashing a motor vehicle,and lying down or jumping in front of a moving object.

关键词： treatment editor alone

来源：

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

Pressurized environments directly influence friction and wear of dry steel contacts—Investigations in a novel high fluid pressure tribometer

引用

Friction 2024年第7期12卷 1599-1617页

作者： Paul REIcHLE jakob BARZ georg UmLAUF günter E.m.TOVAR Institute of Interfacial Process Engineering and Plasma Technology(IgVP) University of StuttgartStuttgart 70569Germany Fraunhofer Institute for Interfacial Engineering and Biotechnology(IgB) Stuttgart 70569Germany

To reduce the usage of classical lubricants in deep drawing,a new tribological system based on volatile lubricants was ***,a volatile medium is injected under high pressure into the interstice between drawing tool and sheet *** on temperature and pressure,the temporary lubricant may exist in its gaseous or liquid *** this study,a novel high fluid pressure tribometer was designed to investigate the friction and wear of dry steel contacts under comparable conditions like in dry deep ***,a new ball-on-disc tribometer was designed and integrated into a high-pressure *** specifically investigate the effects of different environments(technical air,liquid and gaseous carbon dioxide,nitrogen,argon)at atmospheric and high pressure(0.1 mPa,6 mPa)on tribology,the specimens and all components were operating *** the experiments,the friction was measured *** show that the highest friction occurs in air and the lowest in carbon dioxide *** to the experiments,the wear of the specimens was assessed along with changes in surface chemistry related to tribochemical ***,the tribology of the dry sliding contacts is correlated to changes of the surface *** differences as well as similarities regarding the different fluid environments are *** the results show,the differences between the media used are most pronounced at elevated ***,this work gives clear indications on the suitability of volatile lubricants in dry friction or rather gas lubrication,especially for dry deep drawing.

关键词： dry friction and dry wear gas lubrication carbon dioxide tribo-layer dry metal forming

来源：

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

Enhancement of coercivity,permeability,and dielectric properties of co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for memory and high frequency devices

引用

journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： I.sardar m.D.Hossain m.s.sikder m.N.I.Khan m.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Department of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Department ofcomputer science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh material science Division Atomic Energy CentreDhaka1000Bangladesh

spinel cubic ferrites have huge applications in me mory and high frequency *** the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important *** article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FEsEm),energy dispersive X-ray(EDX),vibrating sample magnetometer(Vsm),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the *** XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu *** FTIR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FEsEm images,and it is increased from 121 to 198 *** analysis confirms that doping of the Eu content also changes other hysteresis loop properties of co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the *** permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric *** dependent resistivity and impedance analysis also show the improved *** the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths coercivity Permeability EDX Resistivity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Europium recovery process by means of polymeric nanoparticles functionalized with acrylic acid,curcumin and fumaramide

引用

journal of Rare Earths 2024年第10期42卷 1950-1959页

作者： P.A.martínez-montoya j.m.del Río A.de j.morales-Ramirez m.corea Escuela superior de Ingeniería Química e Industrias Extractivas ESIQIE-IPNDepartamento de Ingeniería Metalúrgica UPALM S/N Col.Lindavista Escuela superior de Ingenieria Química e Industrias Extractivas ESIQIE-IPNLaboratorio de Investigación en Polímeros y NanomaterialesUPALM S/N Col.Lindavista centra de Investigación e Innovación Tecnológica CIITEC-IPNCda.de CECATIs/n

Polymeric nanoparticles of poly(methyl methacrylate) were obtained by emulsion polymerization techniques in a proce ss of two *** particles were functionalized with acrylic acid,curcumin,and fumaramide and three series of polymeric particles were *** incorporation of functional groups was confirmed by Fourier transform-infrared spectrosocopy(FT-IR) and ultraviolet-visible(UV-Vis) *** spherical morphology of particles with an average diameter of 100 nm was observed by scartning electron microscopy(sEm).The polymeric materials were used for recovery of [Eu]from synthetic *** nanoparticles show excellent chelation capacity to trap rare-earth ions,because they recover more than 85% of [Eu] at pH of *** images of sEm after extraction process show arrays between particles with larger average particle sizes to 1.5 *** addition,the particles have a good stripping capacity,exceeding 50% of it,maintaining their homogeneity in morphology and good stability in dispersion for the recovery and stripping processes.A pseudo-second model order is obtained for the extraction and stripping processes while the best results of stripping process are obtained at pH of6.

关键词： chelating effect Emulsion polymerization Extraction process Rare earths stripping process [Eu]recovery

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Velocity equation for grenades while impacting on dry sand media

引用

Defence Technology（防务技术） 2024年第5期35卷 168-173页

作者： martin macko Xuan son Bui Kongsathit Phanthavong Duc Hung Pham van gion Do van minh Do jiri skala University of Defence BrnoCzech Republic Le Quy Don Technical University Ha NoiViet Nam

This paper deals with the collision of sphere shape grenades with sand *** central issue of the article is the establishing of an empirical velocity equation of the grenade while impacting on sand that is used to solve motion equations of the mechanical mechanism inside the impact grenade *** paper focuses on impact velocities that are lower than 5 m s^(-1).An experiment was conducted to study the velocity of the grenade while impacting on dry sand.A high-speed camera video was used to capture the grenade *** grenade velocity in the impact process was generated from these video *** types of fitting curves are used to regress the velocity equation of the grenade while interacting with the sand media and the best-fitting model is *** result shows the regression curve has a high correlation with the experiment data for grenade velocities below 5 m s^(-1).The received regression equation is useful for analyzing the working ability of the inertial mechanism inside the impact grenade or analyzing and choosing the appropriate parameters of each part in the inertial mechanism to meet the required characteristics of the mechanism.

关键词： Dynamic response Impact velocity Impact grenade Low-velocity impact

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Positive health:An integrated quantitative approach in patients with chronic gastrointestinal and hepato-pancreatico-biliary disorders

引用

World journal of gastroenterology 2024年第28期30卷 3418-3427页

作者： Anja H W m Lemlijn-slenter Karolina AP Wijnands gijs van der Hamsvoort Luuk P van Iperen Nico Wolter Angelique E de Rijk Ad Am masclee Department of social medicine Faculty of HealthMedicine and Life sciencesCare and Public Health Research Institute Maastricht UniversityMaastricht 6200 MDLimburgNetherlands Division of gastroenterology and Hepatology Department of Internal MedicineSchool of Nutrition and Translational Research in MetabolismMaastricht 6200 MDLimburgNetherlands social medical Affairs Employee Insurance Agency(UWV)Heerlen 6400 ACLimburgNetherlands Department of Research Academic Knowledge Center Work and Health South-East Netherlands(AKAG-ZON)Heerlen 6400 ACLimburgNetherlands

BAcKgROUND The concept of positive health(PH)supports an integrated approach for patients by taking into account six dimensions of *** approach is especially relevant for patients with chronic *** gastrointestinal and hepatopancreatico-biliary(gI-HPB)disorders are among the top-6 of the most prevalent chronically affected organ *** impact of chronic gI-HPB disorders on individuals may be disproportionally high because:(1)The affected organ system frequently contributes to a malnourished state;and(2)persons with chronic gIHPB disorders are often younger than persons with chronic diseases in other organ *** To describe and quantify the dimensions of PH in patients with chronic gI-HPB *** Prospective,observational questionnaire study performed between 2019 and 2021 in 235 patients with a chronic gIHPB disorder attending the Outpatient Department of the maastricht University medical *** questionnaires and data from patient files were used to quantify the six dimensions of *** consistency was tested with mcDonald’s ***-order Pearson correlations and t-tests were used to assess associations and differences.A P values considered *** The gI-HPB patients scored significantly worse in all dimensions of PH compared to control data or norm scores from the general *** quality of life,participation and daily functioning,gI-HPB patients scored in the same range as patients with chronic disorders in other organ systems,but depressive symptoms(in 35%)and malnutrition(in 45%)were more frequent in patients with chronic gI-HPB *** scores between the six dimensions were only very weak to weak,forcing us to quantify each domain *** All six dimensions of PH are impaired in the gI-HPB *** and depressive symptoms are more prevalent compared to patients with chronic disorders in other organ systems.

关键词： Positive health chronic gut disorders gastrointestinal disorders Hepato-pancreatico-biliary disorders Integrated care

来源：

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

Periodontitis:An often-neglected complication of diabetes

引用

World journal of Diabetes 2024年第3期15卷 318-325页

作者： marina g Kudiyirickal joseph m Pappachan Primary care Dental Practice The Smile ClinicPreston PR16PZUnited Kingdom Department of Endocrinology and metabolism Lancashire Teaching Hospitals NHS TrustPreston PR29HTUnited Kingdom Faculty of science Manchester Metropolitan UniversityManchester M156BHUnited Kingdom Faculty of Biology Medicine and HealthThe University of ManchesterManchester M139PLUnited Kingdom

The bidirectional association between type 2 diabetes mellitus(T2Dm)and periodontitis is now well established,resulting in periodontal disease being considered as the 6th major complication of diabetes mellitus(Dm)after cardiovascular disease,eye disease,neuropathy,nephropathy,and peripheral vascular *** can worsen the virulence and invasiveness of pathogenic oral microbial flora aggravating the local inflammation and infection in those with periodontal *** the other hand,the chemical and immunological mediators released into the circulation as part of periodontal inflammation worsen the systemic insulin resistance with worsening of *** if undiagnosed or left untreated can also result in eventual tooth loss.A study by Xu et al in the World journal of Diabetes examined the predictive factors associated with periodontitis in chinese patients with *** prevalence of periodontitis was found to be 75.7%in this *** on logistic regression analysis,the predictive factors for higher risk were low tooth brushing frequency[odds ratio(OR)=4.3],high triglycerides(Tg;OR=3.31),high total cholesterol(Tc;OR=2.87),higher glycated hemoglobin(HbA1c;OR=2.55),and higher age(OR=1.05)while higher education level was protective(OR=0.53).However,the most influential variables were HbA1c followed by age,Tc,Tg,low education level,brushing frequency,and sex on the random forest model(this model showed higher sensitivity for predicting the risk).A good understanding of the predictors for periodontitis in T2Dm patients is important in prevention,early detection of susceptible patients,and intervention to improve periodontal health and enable long-term glycaemic control as observed by Xu et al.

关键词： Diabetes mellitus Periodontitis Predictive factors cardiovascular disease glycaemic control

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：