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Energy Expenditure of Trotting Gait Under Different Gait Parameters

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Chinese Journal of Mechanical Engineering 2017年第4期30卷 943-950页

作者： xian-Bao chen Feng Gao State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China

Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, opti- mal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is pro- posed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.

关键词： Quadruped robot Energy expenditure Gait Bezier curve

Preparation of Al–La master alloy by ultrasonic method and modification on Al alloy

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Rare Metals 2015年第7期34卷 457-462页

作者： Hong Yan xian-chen Song Xin Huang Department of Materials Processing Engineering School of Mechanical and Electrical EngineeringNanchang University

In this study, two kinds of Al–La master alloys were prepared by ultrasonic method and ordinary mixmelting method, and both of the alloys were added into the Al ***, the microstructure of Al–La master alloy and the modification effect on the Al alloy were investigated using optical microscope(OM), X-ray diffraction(XRD), scanning electron microscope(SEM), and energy disperse spectroscopy(EDS).The results show that because of ultrasonic cavitation and streaming, the grain size of Al–La master alloy prepared by the ultrasonic method is refined, which distributes ***, there is no gas hole,inclusion, or segregation in the Al–La master alloy with aAl, La, and ***, Al–La master alloys show a nice modification for Al alloy, which is much better than that prepared by ordinary mix-melting method.

关键词： Rare earth La Master alloy Al alloy Ultrasonic

Micro-Macro Scale Relationship in Creep Deformation of Ultra High Molecular Weight Polyethylene

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Chinese Journal of Polymer Science 2021年第12期39卷 1665-1672页

作者： Bi-Jin Xiong Zhen-xian chen Jian Kang Key Laboratory of Materials Chemistry for Energy Conversion and Storage(HUST)of Ministry of Education School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology(HUST)Wuhan 430074China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu 610065China

Macroscopic and microscale creep deformations of UHMWPE were investigated by using in situ SAXS.A methodology for the measurement of the local creep deformation of inter-lamellar amorphous phase has been *** local strain of inter-lamellar amorphous phase(£a)and macroscopic strain(£macro)were evaluated and they were compared to study the relati on ship betwee n macroscopic and microscale creep deformation of *** of them exhibit two deformation regions against creep *** entanglements show a strong impact on both the macroscopic and local inter-lamellar amorphous phase creep behavior and they can be well correlated to the molecular weight between two entanglements estimated from strain-hardening *** to the macroscopic creep deformation,local inter-lamellar amorphous layers have a smaller creep *** the local creep measurement,the apparent modulus of inter-lamellar amorphous phase can also be estimated(200

关键词： Ultra-high molecular weight polyethylene Creep Small angle X-ray scattering Microscale

High-quality voice conversion system based on GMM statistical parameters and RBF neural network

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The Journal of China Universities of Posts and Telecommunications 2014年第5期21卷 68-75,93页

作者： chen xian-tong ZHANG Ling-hua College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications

A voice conversion （VC） system was designed based on Gaussian mixture model （GMM） and radial basis function （RBF） neural network. As a voice conversion model, RBF network needs quantities of training data to improve its performance. For one speech, the networks trained by different segments of data have different transformation effects. Since trying segment by segment to obtain the best conversion effect is complex, a conversion method was proposed, that uses GMM for statistics before training RBF network to aim at the problem. The speech transformation and representation using adaptive interpolation of weighted spectrum （STRAIGHT） model is used for accurate extraction of vocal tract spectrum. Then GMM is used to classify the numerous spectral parameters. The obtained mean parameters were trained in RBF network. Experiment reveals that, the soft classification ability of GMM can promptly realize the reduction and classification of training data under the premise of ensuring the training effect. The selection complexity is decreased thereafter. Compared to the conventional RBF network training methods, this method can make the transformation of spectral parameters more effective and improve the quality of converted speech.

关键词： VC system STRAIGHT vocal tract spectrum GMM RBF

Markov Jump Processes in Estimating Sharing of Identity by Descent

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Acta Mathematicae Applicatae Sinica 2021年第1期37卷 183-191页

作者： xian chen Wei GUO Xu-min NI School of Mathematical Sciences Xiamen UniversityXiamen 361005China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China Department of Mathematics Beijing Jiaotong UniversityBeijing 100044China

Identity by descent(IBD)sharing is a very important genomic feature in population genetics which can be used to reconstruct recent demographic *** this paper we provide a framework to estimate IBD sharing for a demographic model called two-population model with *** adopt the structured coalescent theory and use a continuous-time Markov jump process{X(t),t≥0}to describe the genealogical process in such *** we apply Kolmogorov backward equation to calculate the distribution of coalescence time and develop a formula for estimating the IBD *** simulation studies show that our method to estimate IBD sharing for this demographic model is robust and accurate.

关键词： IBD sharing structured coalescent theory Markov jump process Kolmogorov backward equation

Ultrasound-guided needle release plus corticosteroid injection of superficial radial nerve:A case report

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World Journal of Clinical Cases 2022年第4期10卷 1320-1325页

作者： Zeng Zeng Cong-xian chen Department of Ultrasound Zhejiang Provincial People's HospitalHangzhou 310000Zhejiang ProvinceChina

BACKGROUND The radial nerve(RN)splits into two main branches at the elbow:The superficial branch of RN(SBRN)and the deep branch of *** SBRN can be easily damaged in acute trauma due to its superficial *** SUMMARY A 55-year-old male patient injured his right wrist 10 mo ***,suturing and bandaging were performed in the emergency *** months after the scar had healed,he felt numbness and tingling in the dorsal surface of the thumb of the right *** the surgery of resection and SBRN anastomosis were *** pathological findings showed it as traumatic *** months after surgery,the patient felt numbness and tingling in the right dorsal surface of the thumb *** tenderness was marked in the operated *** indicated that the SBRN was adhered to the surrounding *** patient refused further surgical treatment and underwent ultrasound-guided needle release plus corticosteroid injection of the *** weeks later,the tenderness in the surgical area was reduced by 70%,the numbness in the dorsal surface of the thumb of the right hand was reduced by 40%and the nerve swelling evaluated by ultrasound was *** months passed,he did not feel any numbness or tingling sensation of his right *** is the first report of ultrasound-guided needle release plus corticosteroid injection of the *** Ultrasound can evaluate the condition of the RN,and the relationship with surrounding ***-guided needle release plus corticosteroid injection is an effective and safe treatment for SBRN adhesion.

关键词： Ultrasound-guided Needle release Superficial radial nerve Traumatic neuroma Corticosteroid injection Case report

Selective Acid Hydrolysis Condition for the Composition and Linkage with a Fructofuranosyl Backbone of a Polysaccharide from Angelica sinensis (Oliv) Diels

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Chinese Chemical Letters 2006年第10期17卷 1369-1372页

作者： Gui Yun XU Yang chen Ru xian chen Institute of Chemistry Chinese Academy of Sciences Beijing 100080 Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences Beijing 100050

A new polysaccharide was extracted and purified from the roots of Angelica sinensis （Oliv） Diels （ASD）. Its composition and linkage was elucidated by selective hydrolysis and GC/MS analysis of its derivatives. The polysaccharide was made of → 1） Fruf（2→and→6） Glcp （l→as its backbone with highly branched structure. To our best knowledge, this is the first report of the fructose residue in polysaccharides from the roots of the ASD.

关键词： Selective hydrolysis fructofuranosyl backbone GC/MS

Dynamics,impacts,and future projections of Arctic rapid change

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Advances in Climate Change Research 2021年第4期12卷 445-446页

作者： chen xian-Yao ZHANG Tingjun Frontiers Science Center for Deep Ocean Multi-spheres and Earth System Key Laboratory of Physical OceanographyOcean University of ChinaQingdao266100China Laboratory of Ocean Dynamics and Climate Qingdao National Laboratory of Marine Science and TechnologyQingdao266100China Key Laboratory of Western China's Environmental Systems College of Earth and Environmental ScienceLanzhou UniversityLanzhou730000China

Observations show that Arctic sea ice has been dramatically declined,and the surface temperature in Arctic region is dramatically increasing since *** the end of 2020,the summer sea ice extent had been decreased by more than 50%comparing with the area in the late *** increasing rate of surface atmospheric and oceanic temperature was about 2-3 times faster than that of the global average(Meredith et al.,2019).Arctic is experiencing rapid change.

关键词： change. Arctic oceanic

Colorimetric enantiodiscrimination of mandelic acid by indicator displacement assay

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Chinese Chemical Letters 2015年第8期26卷 1019-1021页

作者： Xue-xian chen Li-Ming Yuan School of Energy and Environment Yunnan Normal University

The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu（II） is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu（II）. The △A could be increased to 0.12 by changing the ratio of（＋）- and（-）-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus △A relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.

关键词： proline indicator reserved resultant calibration excess violet guest isotherm tuned