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第30届中国控制与决策会议

作者： Han Wu Hongxu Ma Qing Wei Jian Wang Honglei An College of Intelligence Science and Engineering National University of Defense Technology

Exoskeleton is a kind of wearable robot that can help human achieve special targets. The study comes up with a novel force control method based on dual foot force sensors, named proportional force control. First a dual foot force sensors mechanism is introduced, and then a simpler one dimension lower limb model is presented in order to analysis the human machine system conveniently. After that two normal control methods(trajectory tracking control and desired force control) are listed for the purpose of being compared with the proportional force control. At last simulations are carried out and the results show that force control based on dual foot force sensors can augment human strength proportionally as well as feedback pilots a kind of directly perceived feeling.

关键词： Exoskeleton Lower Limb Force Control Augmentation

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THE BIOMECHANICAL STUDY OF DIFFERENT POSTERIOR CRUCIATE LIGAMENT RECONSTRUCTION techNIQUES

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JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY 2018年第8期18卷

作者： Guo, Na Qi, Yansong Yang, Biao Han, Zhonghao Hu, Lei Xu, Yongsheng Wang, Tianmiao Yu, Jiakuo Beihang Univ Sch Mech Engn & Automat Beijing Peoples R China Peking Univ Third Hosp Inst Sports Med Knee Surg Dept Beijing 100191 Peoples R China Inner Mongolia Peoples Hosp Dept Orthoped Hohhot 010017 Peoples R China Peking Univ Third Hosp Beijing Peoples R China

The main purpose of our study was to evaluate the biomechanics of different posterior cruciate ligament (PCL) reconstruction techniques. Seven fresh cadaver knees were collected. A 6-D OF robot arm was used to test the biomechanical parameters, including the posterior stability, the lateral stability and the rotation stability of different PCL reconstruction techniques. Each group was tested at the knee flexion of 0, 30 degrees, 60 degrees, 90 degrees and 120 degrees, under the following conditions respectively: a posterior force of 134 N, an internal and external rotation torque of 5N . m, a varus and valgus torque of 10N . m, and a combination of 100 N posterior force and 5N . m external rotation torque. The posterior tibia translation and the rotational angle of the 4-tunnel double-bundle PCL reconstruction group were significantly lower than that of 3-tunnel double-bundle group and the single-bundle group;the posterior tibia translation valgus-varus-angle were lower at some specified flexion angle. No statistical difference was found between the anatomic 4-tunnel bundle group and the intact knee group concerning the posterior tibia translation, the rotational angle, and the valgus-varus-angle. This study showed that the biomechanics of PCL of 4-tunnel double-bundle reconstruction was closer to the intact knees than the other two reconstruction methods.

关键词： Knee joint stereo-vision force sensor posterior cruciate ligament biomechanical properties

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A temperature characteristic research and compensation design for micro-machined gyroscope

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MODERN PHYSICS LETTERS B 2017年第6期31卷

作者： Fu, Qiang Di, Xin-Peng Chen, Wei-Ping Yin, Liang Liu, Xiao-Wei Harbin Inst Technol MEMS Ctr 92 St Xidazhi Harbin 150001 Heilongjiang Peoples R China

The all temperature range stability is the most important technology of MEMS angular velocity sensor according to the principle of capacity detecting. The correlation be tween driven force and zero-point of sensor is summarized according to the temperature characteristic of the air-damping and resonant frequency of sensor header. A constant trans-conductance high-linearity amplifier is designed to realize the low phase-drift and low amplitude-drift interface circuit at all-temperature range. The chip is fabricated in a standard 0.5 mu m CMOS process. Compensation achieved by driven force to zero-point drift caused by the stiffness of physical construction and air-damping is adopted. Moreover, the driven force can be obtained from the drive-circuit to avoid the complex sampling. The test result shows that the zero-point drift is lower than 30 degrees/h (1-sigma) at the temperature range from -40 degrees C to 60 degrees C after three-order compensation made by force.

关键词： Gyroscope all temperature range stability interface circuit

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Pd catalyst supported on ZrO₂-Al₂O₃ by double-solvent method for methane oxidation under lean conditions

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CANADIAN JOURNAL OF CHEMICAL ENGINEERING 2017年第6期95卷 1117-1123页

作者： Li, Guangxia Hu, Wei Huang, Fujin Chen, Jianjun Gong, MaoChu Yuan, Shandong Chen, Yaoqiang Zhong, Lin Sichuan Univ Coll Chem Engn Chengdu 610064 Peoples R China Sichuan Univ Coll Chem Chengdu 610064 Peoples R China Sichuan Univ Inst New Energy & Low Carbon Technol Chengdu 610064 Peoples R China

The Pd catalyst supported on the Zr0.5Al0.5O1.75 composite material was prepared by the conventional impregnation and double solvent impregnation method. The effects of preparation method on the catalytic properties of the Pd/Zr0.5Al0.5O1.75 catalyst for methane combustion have been investigated systematically. The measurement was evaluated in a multiple fixed-bed continuous flow micro-reactor by passing a gas mixture simulating the exhaust emissions from lean-burn natural gas vehicles. The as-prepared catalysts were characterized by CO chemical adsorption, transmission electron microscopy (TEM), hydrogen-temperature programmed reduction (H-2-TPR),and X-ray photoelectron spectroscopy (XPS) measurements. The results of TEM and CO chemisorption showed that the introduction of double solvent during the preparation of Pd/Zr0.5Al0.5O1.75 was beneficial for the dispersion of Pd nanoparticles and obtained superior resistance to the sintering of Pd on the surface of Zr0.5Al0.5O1.75. The H-2-TPR measurements demonstrated that the double solvent method increased the reducibility of the Pd catalyst. The XPS results further indicated that more active surface oxygen species also can be formed on the catalyst prepared via double solvent process. Thus, this catalyst exhibited better catalytic performance and hydrothermal aging resistance in the methane oxidation compared to its analogues with the same Pd content prepared by the conventional impregnation method.

关键词： aluminum Pd catalyst double-solvent methane oxidation lean condition

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Optimization of soybean roasting parameters in developing nutritious and lipoxygenase free soymilk

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JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2017年第4期11卷 1899-1908页

作者： Navicha, Willard Burton Hua, Yufei Masamba, Kingsley Kong, Xiangzhen Zhang, Caimeng Jiangnan Univ Sch Food Sci & Technol State Key Lab Food Sci & Technol 1800 Lihu Ave Wuxi 214122 Jiangsu Peoples R China Domasi Coll Educ Dept Human Ecol POB 49 Zomba Malawi Lilongwe Univ Agr & Nat Resources Dept Food Sci & Technol Box 219 Lilongwe Malawi

It is generally acknowledged that despite the superior nutritional value of soymilk, the presence of off-flavours catalysed by lipoxygenase (LOX) activities has to some extent negatively influenced the overall acceptability of soymilk in consumers. In this current study, the effect of roasting soybeans at different temperatures (110-130 degrees C) and times (20-120 min) on physical, chemical properties and LOX activity of soymilk was investigated in order to establish optimum soybean roasting conditions for developing nutritious and LOX free soymilk. Results have revealed that subjecting soybeans to increased roasting temperature and time negatively affected physical chemical properties of soymilk by decreasing the yield, solid content, colour and nutritive value. On the other hand, roasting soybeans at a relatively low temperature of 110 degrees C for 80 min significantly inactivated LOX but retained adequate protein content in soymilk. The findings of this study have demonstrated that careful selection of roasting conditions can be a useful strategy for inactivating LOX activity in development of a more acceptable soymilk product.

关键词： Soybean roasting temperature Soybean roasting time Soymilk Lipoxygenase activity Nutritive value Optimum roasting conditions

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Fence-Free Synchronization with Dynamically Serialized Synchronization Variables

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2017年第12期28卷 3486-3500页

作者： Hong, Yang Zheng, Yang Guan, Haibing Zang, Binyu Chen, Haibo Shanghai Jiao Tong Univ Shanghai Key Lab Scalable Comp & Syst Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Software Sch Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Inst Parallel & Distributed Syst Shanghai 200240 Peoples R China

Memory fences are widely used to ensure the correctness for synchronization constructs on machines with relaxed consistency models. However, they are expensive and usually impose over-constrained ordering that causes unnecessary CPU stalls. In this paper, we observe that memory fences in TSO are merely intended to order synchronization variables. Based on this observation, we rethink the hardware-software interface of synchronization constructs on multicore processors and propose a new design called Sync-Order that differentiates synchronization variables (sync-vars) from normal ones. Sync-Order reduces hardware complexity such that the processor only needs to serialize the ordering among sync-vars. Its simplicity makes it easy to be integrated to the directory controller and it supports distributed directory, a missing feature in prior designs. We show that Sync-Order eliminates traditional fences on all sides of synchronization constructs (instead of only one side in prior work) and requires small effort for a programmer or compiler to annotate sync-vars. Our experimental results show that Sync-Order significantly reduces CPU stalls and boosts the performance of a set of synchronization constructs and concurrent data structures by 10 percent;meanwhile, the fence overhead of full applications from SPLASH-2 and PARSEC is reduced from 42 to 3 percent.

关键词： Fences synchronization memory consistency sequential consistency parallel programming shared-memory multiprocessors

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Evolutionary processes and sources of high-nitrate haze episodes over Beijing,Spring

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Journal of Environmental Sciences 2017年第4期29卷 142-151页

作者： Ting Yang Yele Sun Wei Zhang Zifa Wang Xingang Liu Pingqing Fu Xiquan Wang State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Aviation Meteorological Center of China Beijing 100021 China State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing 100089 China

Rare and consecutive high-nitrate haze pollution episodes were observed in Beijing in spring2012. We present detailed characterization of the sources and evolutionary mechanisms of this haze pollution, and focus on an episode that occurred between 15 and 26 April. Submicron aerosol species were found to be substantially elevated during haze episodes, and nitrates showed the largest increase and occupation（average： 32.2%） in non-refractory submicron particles（NR-PM1）, which did not occur in other seasons as previously reported. The haze episode（HE） was divided into three sub-episodes, HEa, HEb, and HEc. During HEa and HEc, a shallow boundary layer, stagnant meteorological conditions, and high humidity favored the formation of high-nitrate concentrations, which were mainly produced by three different processes —daytime photochemical production, gas-particle partitioning, and nighttime heterogeneous reactions — and the decline in visibility was mainly induced by ***, unlike HEa and HEc, during HEb, the contribution of high nitrates was partly from the transport of haze from the southeast of Beijing — the transport pathway was observed at ~800–1000 m by aerosol Lidar —and the decline in visibility during HEb was primarily caused by PM（2.5）. Our results provide useful information for air quality improvement strategies in Beijing during Spring.

关键词： Haze Nitrate Sources Lidar Aerosol Chemical Speciation Monitor Boundary layer

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Bone marrow mesenchymal stem cell-derived acellular matrix-coated chitosan/silk scaffolds for neural tissue regeneration

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JOURNAL OF MATERIALS CHEMISTRY B 2017年第6期5卷 1246-1257页

作者： Xue, Chengbin Ren, Hechun Zhu, Hui Gu, Xiaokun Guo, Qi Zhou, Yi Huang, Jing Wang, Shengran Zha, Guangbin Gu, Jianhui Yang, Yumin Gu, Yun Gu, Xiaosong Nanjing Univ State Key Lab Pharmaceut Biotechnol Model Anim Res Ctr Nanjing Biomed Res Inst Nanjing 210061 Jiangsu Peoples R China Nanjing Univ MOE Key Lab Model Anim Dis Study Model Anim Res Ctr Nanjing Biomed Res Inst Nanjing 210061 Jiangsu Peoples R China Nantong Univ Coinnovat Ctr Neuroregenerat Minist Educ 19 Qixiu Rd Nantong 226001 JS Peoples R China Nantong Univ Coinnovat Ctr Neuroregenerat Jiangsu Key Lab Neuroregenerat 19 Qixiu Rd Nantong 226001 JS Peoples R China Nantong Univ Res Ctr Clin Med Affiliated Hosp 20 Xisi Rd Nantong 226001 JS Peoples R China Nantong Univ Dept Hand Surg Affiliated Hosp 20 Xisi Rd Nantong 226001 JS Peoples R China Jilin Univ China Japan Union Hosp Dept Hand Surg Changchun 130033 Jilin Province Peoples R China

Extracellular/acellular matrix-containing neural scaffolds represent a promising design of a tissue engineered nerve graft (TENG) for peripheral nerve repair. In this study, we engineered a composite neural scaffold by culturing dog bone marrow mesenchymal stem cells (BMSCs) onto the surface of a chitosan/silk fibroin-based scaffold and then exposing the cell culture to decellularization to deposit acellular matrix (ACM) coatings on the scaffold. This natural biomaterial-based, cell-derived ACM-coated neural scaffold, as a novel nerve graft, was used to bridge a 60 mm long nerve gap in a dog sciatic nerve. At 12 months after grafting, behavioral, functional, and histological evaluation indicated that our developed neural scaffold achieved satisfactory regenerative outcomes, which were very close to those achieved by autologous nerve grafts, the accepted golden standard for peripheral nerve repair. Moreover, additional therapeutic benefits produced by the modification of a neural scaffold with BMSC-derived ACM may be associated with the unique neural activity of the ACM, as evidenced by in vitro experimental findings that the ACM significantly enhanced axonal regrowth and Schwann cell proliferation. Our results will provide a further experimental basis for the translation of ACM-containing neural scaffolds into the clinic.

关键词： Chitosan

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Improving the electrification rate of the vehicle miles traveled in Beijing: A data-driven approach

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TRANSPORTATION research PART A-POLICY AND PRACTICE 2017年 97卷 106-120页

作者： Li, Meng Jia, Yinghao Shen, Zuojun He, Fang Tsinghua Univ Dept Civil Engn Beijing 100084 Peoples R China Tsinghua Univ Dept Ind Engn Beijing 100084 Peoples R China Univ Calif Berkeley Dept Civil & Environm Engn Berkeley CA 94720 USA Univ Calif Berkeley Dept Ind Engn & Operat Res Berkeley CA 94720 USA

Electric vehicles (EV) are promoted as a foreseeable future vehicle technology to reduce dependence on fossil fuels and greenhouse gas emissions associated with conventional vehicles. This paper proposes a data-driven approach to improving the electrification rate of the vehicle miles traveled (VMT) by taxi fleet in Beijing. Specifically, based on the gathered real-time vehicle trajectory data of 46,765 taxis in Beijing, we conduct time-series simulations to derive insights for the public charging station deployment plan, including the locations of public charging stations, the number of chargers at each station and their types. The proposed simulation model defines the electric vehicle charging opportunity from the aspects of time window, charging demand and charger availability, and further incorporates the heterogeneous travel patterns of individual vehicles. Although this study only examines one type of fleet in a specific city, the methodological framework is readily applicable to other cities and types of fleet with similar dataset available, and the analysis results contribute to our understanding on electric vehicle's charging behavior. Simulation results indicate that: (i) locating public charging stations to the clustered charging time windows is a superior strategy to increase the electrification rate of VMT;(ii) deploying 500 public stations (each includes 30 slow chargers) can electrify 170 million VMT in Beijing in two months, if EV's battery range is 80km and home charging is available;(iii) appropriately combining slow and fast chargers in public charging stations contributes to the electrification rate;(iv) breaking the charging stations into smaller ones and spatially distributing them will increase the electrification rate of VMT;(v) feeding the information of availability of chargers in charging stations to drivers can increase the electrification rate of VMT;(vi) the impact of stochasticity embedded in the trajectory data can be significantly mi

关键词： Trajectory dataset Plug-in hybrid electric vehicle Charging opportunity Electrification rate Public charging stations Vehicle miles traveled

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Synthesizing value-added products from methane by a new Methylomonas

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JOURNAL OF APPLIED MICROBIOLOGY 2017年第5期123卷 1214-1227页

作者： Guo, W. Li, D. He, R. Wu, M. Chen, W. Gao, F. Zhang, Z. Yao, Y. Yu, L. Chen, S. Chinese Acad Sci Tianjin Inst Ind Biotechnol Tianjin Key Lab Ind Biol Syst & Bioproc Engn Tianjin Peoples R China Dalian Univ Technol Food & Environm Dept Panjin Peoples R China Chinese Acad Sci Tianjin Inst Ind Biotechnol Technol Support Ctr Tianjin Peoples R China Washington State Univ Dept Biol Syst Engn Pullman WA 99164 USA

AimsMethane and methanol are potential carbon sources of industrial micro-organisms in addition to crop-derived bio-carbon sources. Methanotrophs that can utilize these simple, stable and large amounts chemicals are expected to be developed into cell factories' for the production of specific chemicals. In this study, a methanotroph that can synthesize lycopene, C-30 carotenoid and exopolysaccharides (EPS) with relative better performances from C1 substrates was isolated, and its performances were evaluated. Methods and ResultsThe isolated strain was identified as Methylomonas sp. ZR1 based on 16S rRNA sequence analysis. Its maximum specific growth rate achieved 0200h(-1) under flask culture conditions, and 0386h(-1) in bubble column reactors. ZR1 was able to utilize 35gl(-1) of methanol and even exhibited slight growth in the presence of 40gl(-1) of methanol. Furthermore, ZR1 was proved to synthesize lycopene (C-40 carotenoids) besides the C-30 carotenoids through HPLC-DAD and HPLC-MS/MS analysis methods. Its carotenoid extracts exhibited excellent antioxidative activities measured by the ABTS(+) method. Plenty of polysaccharides were also synthesized by ZR1, the components of the polysaccharides were identified as glucose, mannose and galactose with a proportion of 1:2:1 by GC-MS, and its yield achieved 013gg(-1) cell dry weight. ConclusionsThe isolated strain has great potential for the production of value-added bioproducts from C1 compounds because of its excellent C1 substrate utilizing abilities and its abilities to naturally synthesize lycopene, C-30 carotenoids and EPS. Significance and Impact of the StudyIn this study, we isolated a fast-growing methanotroph, its C1 carbon substrate utilizing ability is excellent in comparison with reported methanotrophs. Furthermore, besides polysaccharides and C-30 carotenoids which were commonly synthesized by methanotrophs, our findings suggested that C-40 lycopene could also be naturally synthesized from methane by meth

关键词： bioproducts carotenoid exopolysaccharides fast growing lycopene methane methanol tolerance methylomonas

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