检索结果-南通市图书馆

Underlying Mechanisms of Tai-Chi-Chuan Training for Improving Balance Ability in the Elders

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2014年第6期20卷 409-415页

作者：郭藍遠楊照彬尤玉琳陳勝凱楊志鴻侯易佑吳汶蘭 department of Sports Medicine College of MedicineKaohsiung Medical University department of Physical Medicine and Rehabilitation Changhua Christian Hospital department of Orthopedic Kaohsiung Medical UniversityHospital department of Physical Therapy Tzu-Chi College of Technology department of Electrical engineering Far East University

Objective： To compare balance ability between elderly individuals who practiced Tai-Chi-Chuan （TCC） for average 9.64 years and elderly individuals who did not practice TCC and its relationship with lower extremity muscle strength and ankle proprioception. Methods： Twenty-five elderly volunteers were divided into two groups according to their TCC practcing experience. Sixteen were TCC group and the other nine were control population. Subjects completed a static balance test and ankle proprioception test using a custom-designed evaluation system, and concentric and eccentric knee extensor and flexor muscle strength tests. Subjects stood on the plate form to measure the proprioception in functional standing position which was differed from the previous studies. Multiple linear regressions were also used to predict the important factor affecting balance. Results： TCC group performed better than the control group in balance, proprioception, and muscle strength of lower extremity. The proprioception was the most important factor related to balance ability and it can be accounted for explaining 44% of variance in medial-lateral sway direction, and 53% of variance in antero-posterior sway direction. The proprioception may be a more important factor which affecting the balance ability. Conclusion： TCC training is recommended to the elders; as it can improve balance ability through better proprioception.

关键词： elders Tai-Chi-Chuan ankle proprioception muscle strength balance predicted factor affectingthe balance ability

Effects of CeO_(2)pre-calcined at different temperatures on the performance of Pt/CeO_(2)-C electrocatalyst for methanol oxidation reaction

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2021年第7期28卷 1224-1232页

作者： Guo-qing Li Pu-kang Wen Chen-qiang Gao Tian-yi Zhang Jun-yang Hu Yu-hao Zhang Shi-you Guan Qing-feng Li Bing Li School of mechanical and Power engineering East China University of Science and TechnologyShanghai 200237China School of Materials Science and engineering East China University of Science and TechnologyShanghai 200237China Institute for Sustainable Energy College of SciencesShanghai UniversityShanghai 200237China department of Energy Conversion and Storage Technical University of DenmarkLyngby 2800Denmark

Pt/CeO_(2)-C catalysts with CeO_(2)pre-calcined at 300-600 ℃were synthesized by combining hydrothermal calcination and wet *** effects of the pre-calcined CeO_(2)on the performance of Pt/CeO_(2)-C catalysts in methanol oxidation were *** Pt/CeO_(2)-C catalysts with pre-calcined CeO_(2)at 300-600 ℃showed an average particle size of 2.6-2.9 nm and exhibited better methanol elec-tro-oxidation catalytic activity than the commercial Pt/C *** specific,the Pt/CeO_(2)-C catalysts with pre-calcined CeO_(2)at 400 ℃dis-played the highest electrochemical surface area value of 68.14 m2·g−1 and If/Ib ratio(the ratio of the forward scanning peak current density(If)and the backward scanning peak current density(Ib))of 1.26,which are considerably larger than those(53.23 m2·g−1 and 0.79,respectively)of the commercial Pt/C catalyst,implying greatly enhanced CO tolerance.

关键词： direct methanol fuel cell platinum/cerium dioxide-carbon electrocatalyst methanol oxidation

Emerging of Stochastic Dynamical Equalities and Steady State Thermodynamics from Darwinian Dynamics

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第5期49卷 1073-1090页

作者： P.Ao department of mechanical engineering and department of Physics University of WashingtonSeattleWA 98195USA

The evolutionary dynamics first conceived by Darwin and Wallace, referring to as Darwinian dynamics in the present paper, has been found to be universally valid in biology. The statistical mechanics and thermodynamics, while enormous successful in physics, have been in an awkward situation of wanting a consistent dynamical understanding. Here we present from a formal point of view an exploration of the connection between thermodynamics and Darwinian dynamics and a few related topics. We first show that the stochasticity in Darwinian dynamics implies the existence temperature, hence the canonical distribution of Boltzmann-Gibbs type. In term of relative entropy the Second Law of thermodynamics is dynamically demonstrated without detailed balance condition, and is valid regardless of size of the system. In particular, the dynamical component responsible for breaking detailed balance condition does not contribute to the change of the relative entropy. Two types of stochastic dynamical equalities of current interest are explicitly discussed in the present approach： One is based on Feynman-Kac formula and another is a generalization of Einstein relation. Both are directly accessible to experimental tests. Our demonstration indicates that Darwinian dynamics represents logically a simple and straightforward starting point for statistical mechanics and thermodynamics and is complementary to and consistent with conservative dynamics that dominates the physical sciences. Present exploration suggests the existence of a unified stochastic dynamical framework both near and far from equilibrium.

关键词： non-equilibrium processes Darwinian dynamics generalized Einstein relation absence of detailed balance stochastic dynamical equalities

Flexible, diamond-based microelectrodes fabricated using the diamond growth side for neural sensing

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2020年第1期6卷 742-753页

作者： Bin Fan Cory A.Rusinek Cort H.Thompson Monica Setien Yue Guo Robert Rechenberg Yan Gong Arthur J.Weber Michael F.Becker Erin Purcell Wen Li department of Electrical and Computer engineering Michigan State UniversityEast LansingMIUSA Fraunhofer USA Center for Coatings and Diamond Technologies East LansingMIUSA department of Biomedical engineering Michigan State UniversityEast LansingMIUSA department of Physiology Michigan State UniversityEast LansingMIUSA

Diamond possesses many favorable properties for biochemical sensors,including biocompatibility,chemical inertness,resistance to biofouling,an extremely wide potential window,and low double-layer *** hardness of diamond,however,has hindered its applications in neural implants due to the mechanical property mismatch between diamond and soft nervous ***,we present a flexible,diamond-based microelectrode probe consisting of multichannel boron-doped polycrystalline diamond(BDD)microelectrodes on a soft Parylene C *** developed and optimized a wafer-scale fabrication approach that allows the use of the growth side of the BDD thin film as the sensing *** to the nucleation surface,the BDD growth side exhibited a rougher morphology,a higher sp^(3) content,a wider water potential window,and a lower background *** dopamine(DA)sensing capability of the BDD growth surface electrodes was validated in a 1.0 mM DA solution,which shows better sensitivity and stability than the BDD nucleation surface *** results of these comparative studies suggest that using the BDD growth surface for making implantable microelectrodes has significant advantages in terms of the sensitivity,selectivity,and stability of a neural ***,we validated the functionality of the BDD growth side electrodes for neural recordings both in vitro and in *** biocompatibility of the microcrystalline diamond film was also assessed in vitro using rat cortical neuron cultures.

关键词： neural film diamond

3D printing of metal-based materials for renewable energy applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2021年第7期14卷 2105-2132页

作者： Shahryar Mooraj Zhen Qi Cheng Zhu Jie Ren Siyuan Peng Liang Liu Shengbiao Zhang Shuai Feng Fanyue Kong Yanfang Liu Eric B.Duoss Sarah Baker Wen Chen department of mechanical and Industrial engineering University of MassachusettsAmherstMA01003-2210USA Lawrence Livermore National Laboratory 7000 East AvenueLivermoreCA94550USA department of Materials Science and engineering Rensselaer Polytechnic InstituteTroyNY12180USA

Large-scale renewable energy must overcome conversion and storage challenges before it can replace fossil fuels due to its intermittent ***,current sustainable energy devices still suffer from high cost,low efficiency,and poor service life ***,porous metal-based materials have been widely used as desirable cross-functional platforms for electrochemical and photochemical energy systems for their unique electrical conductivity,catalytic activity,and chemical *** tailor the porosity length scale,ordering,and compositions,3D printing has been applied as a disruptive manufacturing revolution to create complex architected components by directly joining sequential layers into designed *** article intends to summarize cutting-edge advances of metal-based materials for renewable energy devices(e.g.,fuel cells,solar cells,supercapacitors,and batteries)over the past decade.

关键词： renewable energy metal catalysts nanomaterials porous structure 3D printing additive manufacturing

Identification of Composite-Metal Bolted Structures with Nonlinear Contact Effect

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第2期70卷 3383-3397页

作者： Mohammad Ghalandari Ibrahim Mahariq Majid Pourghasem Hasan Mulki Fahd Jarad department of Aerospace engineering Sharif University of TechnologyTehranIran College of engineering and Technology American University of theMiddle EastKuwait Faculty of mechanical and Mechatronics engineering IHUTehranIran department of Mathematics Cankaya UniversityEtimesgutAnkaraTurkey department of Medical Research China Medical University HospitalChina Medical UniversityTaichungTaiwan

The middle layer model has been used in recent years to better describe the connection behavior in composite *** influencing parameters including low pre-screw and high preload have the main effects on nonlinear behavior of the connection as well as the amplitude of the excitation force applied to the ***,in this study,the effects of connection behavior on the general structure in two sections of increasing damping and reducing the stiffness of the structures that lead to non-linear phenomena have been *** to the fact that in composite structure we are faced to the limitation of increasing screw preload which tend to structural damage,so the investigation on the hybrid connection(metal-composite)behavior is *** this research,using the two-dimensional middle layer theory,the stiffness properties of the connection are modeled by normal stiffness and the connection damping is modeled using the structural damping in the shear *** frequency response diagrams have been extracted twice for two different excitation forces and then proposed by a high-order multitasking approximation according to the response range of the nonlinear finite element model for stiffness and damping of the *** effect of increasing the amplitude of the excitation force and decreasing the preload of the screw on the nonlinear behavior of the component has been *** results show that the limited presented novel component model has been accurately verified on the model obtained from the vibration experimental test and the reduction of nonlinear model updating based on that is *** comparison results show good agreementwith a maximumof 1.33%error.

关键词： Nonlinear equation hybrid joint behavior thin laminated element nonlinear frequency response function

The ReaxFF reactive force-field: development, applications and future directions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2016年第1期2卷 202-215页

作者： Thomas P Senftle Sungwook Hong Md Mahbubul Islam Sudhir B Kylasa Yuanxia Zheng Yun Kyung Shin Chad Junkermeier Roman Engel-Herbert Michael J Janik Hasan Metin Aktulga Toon Verstraelen Ananth Grama Adri CT van Duin department of Chemical engineering Pennsylvania State UniversityUniversity ParkPAUSA department of mechanical and Nuclear engineering Pennsylvania State UniversityUniversity ParkPAUSA department of Computer Science and engineering PurdueWest LafayetteINUSA department of Materials Science and engineering Pennsylvania State UniversityUniversity ParkPAUSA department of Computer Science and engineering Michigan State UniversityEast LansingMIUSA Center for Molecular Modeling(CMM) Ghent UniversityZwijnaardeBelgium

The reactive force-field(ReaxFF)interatomic potential is a powerful computational tool for exploring,developing and optimizing material *** based on the principles of quantum mechanics(QM),while offering valuable theoretical guidance at the electronic level,are often too computationally intense for simulations that consider the full dynamic evolution of a ***,empirical interatomic potentials that are based on classical principles require significantly fewer computational resources,which enables simulations to better describe dynamic processes over longer timeframes and on larger *** methods,however,typically require a predefined connectivity between atoms,precluding simulations that involve reactive *** ReaxFF method was developed to help bridge this *** the gap from the classical side,ReaxFF casts the empirical interatomic potential within a bond-order formalism,thus implicitly describing chemical bonding without expensive QM *** article provides an overview of the development,application,and future directions of the ReaxFF method.

关键词： properties directions bonding

Effect of melting temperature on microstructural evolutions, behavior and corrosion morphology of Hadfield austenitic manganese steel in the casting process

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第12期25卷 1431-1438页

作者： Masoud Sabzi Sadegh Moeini far Saeid Mersagh Dezfuli Young Researchers and Elite Club Dezful Branch Islamic Azad University department of mechanical engineering Islamic Azad University department of Materials Science and engineering Islamic Azad University

In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium silicate/CO_2 method, using a blind riser, and then the desired molten steel was obtained using a coreless induction furnace. The casting was performed at melting temperatures of 1350, 1400, 1450, and 1500°C, and the cast blocks were immediately quenched in water. Optical microscopy was used to analyze the microstructure, and scanning electron microscopy(SEM) and X-ray diffractrometry(XRD) were used to analyze the corrosion morphology and phase formation in the microstructure, respectively. The corrosion behavior of the samples was analyzed using a potentiodynamic polarization test and electrochemical impedance spectroscopy(EIS) in 3.5 wt% NaCl. The optical microscopy observations and XRD patterns show that the increase in melting temperature led to a decrease of carbides and an increase in the austenite grain size in the Hadfield steel microstructure. The corrosion tests results show that with increasing melting temperature in the casting process, Hadfield steel shows a higher corrosion resistance. The SEM images of the corrosion morphologies show that the reduction of melting temperature in the Hadfield steel casting process induced micro-galvanic corrosion conditions.

关键词： Hadfield steel casting process melting temperature microstructural evolutions corrosion behavior corrosion morphology

Analysis of Second-Harmonic Generation of Low-Frequency Dilatational Lamb Waves in a Two-Layered Composite Plate

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2018年第11期35卷 46-50页

作者： Han Chen Ming-Xi Deng Ning Hu Ming-Liang Li Guang-Jian Gao Yan-Xun Xiang department of Physics Army Logistics University of PLAChongqing 401331 College of Aerospace engineering Key Laboratory of Optoelectronic Technology and Systems（Ministry of Education）Chongqing UniversityChongqing 400044 School of mechanical and Power engineering East China University of Science and TechnologyShanghai 200237

We analyze the effect of second-harmonic generation（SHG） of primary Lamb wave propagation in a two-layered composite plate, and then investigate the influence of interfacial properties on the said effect at low frequency. It is found that changes in the interfacial properties essentially affect the dispersion relation and then the maximum cumulative distance of the double-frequency Lamb wave generated. This will remarkably influence the efficiency of SHG. To overcome the complications arising from the inherent dispersion and multimode natures in analyzing the SHG effect of Lamb waves, the present work focuses on the analysis of the SHG effect of low-frequency dilatational Lamb wave propagation. Both the numerical analysis and finite element simulation indicate that the SHG effect of low-frequency dilatational Lamb wave propagation is found to be much more sensitive to changes in the interfacial properties than primary Lamb waves. The potential of using the SHG effect of low-frequency dilatational Lamb waves to characterize a minor change in the interfacial properties is analyzed.

关键词： SHG Analysis of Second-Harmonic Generation of Low-Frequency Dilatational Lamb Waves in a Two-Layered Composite Plate