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mobility EVALUATION AND INNOVATION OF WHEELED SPACE ROVER

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Chinese Journal of Mechanical Engineering 2006年第2期19卷 187-190页

作者： SHANG Jianzhong LU0 Zirong LI Shengyi TANG Li School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074 China School of Mechatronics Engineering and Automation National University of Defense TechnologyChangsha 410073 China

The mission and function requirements of lunar rover are analyzed, based on virtual prototype technology, the mobility evaluation theory and method for wheeled space rover are proposed, which provide a new way to study the innovative design of lunar rover. Based on the above theoretical system, an innovative lunar rover suspension system, which adopts a two-crank-slider mechanism, is proposed, and its dynamics model is created. Adopting virtual prototype technology, the ground adaptability, over-obstacle ability and driving placidity of the rover are evaluated in the virtual prototype software ADAMS. The analysis results show that the rover provides a high degree of mobility.

关键词： Space rover mobility Virtual prototype Suspension

mobility and constant-orientation workspace analysis of 4UPS-UPU parallel mechanism

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High Technology Letters 2014年第2期20卷 124-130页

作者：雷静桃 Hu Lei Cao Yuanlong Wang Tianmiao School of Mechatronic Engineering and Automation Shanghai University School of Mechanical Engineering and Automation Beihang University

One of the key issues for parallel mechanism is the kinematic characteristics,especially the workspace which varies with configuration parameters.A kind of 4UPS-UPU parallel mechanism is designed and its workspace is studied in this ***,the mobility of the 4UPS-UPU parallel mechanism is analyzed based on the reciprocal screw theory,and the motion and constraint screw systems of the parallel mechanism are *** the inverse kinematics is derived by the closed-form kinematics *** boundary search method in the polar coordinate system is presented to analyze the constant-orientation workspace of the parallel ***,the influence factors relevant to the workspace,such as the structural parameters and kinematics parameters are analyzed in *** relationship between the workspace volume and different parameters are *** conclusions can be used for parameters optimization and path planning of the parallel mechanism.

关键词： parallel mechanism (PM) screw theory mobility boundary search method workspace

Facile and fast growth of high mobility nanoribbons of ZrTe5

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Chinese Physics B 2020年第6期29卷 69-74页

作者： Jingyue Wang Jingjing Niu Xinqi Li Xiumei Ma Yuan Yao Xiaosong Wu State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Peking UniversityBeijing 100871China Institute of Physics Chinese Academy of SciencesBeijing 100190China Frontiers Science Center for Nano-optoelectronics and Collaborative Innovation Center of Quantum Matter Peking UniversityBeijing 100871China Department of Physics South University of Science and Technology of ChinaShenzhen 518055China

Recently, ZrTe5 has received a lot of attention as it exhibits various topological phases, such as weak and strong topological insulators, a Dirac semimetal, a three-dimensional quantum Hall state, and a quantum spin Hall insulator in the monolayer limit. While most of studies have been focused on the three-dimensional bulk material, it is highly desired to obtain nanostructured materials due to their advantages in device applications. We report the synthesis and characterizations of ZrTe5 nanoribbons. Via a silicon-assisted chemical vapor transport method, long nanoribbons with thickness as thin as 20 nm can be grown. The growth rate is over an order of magnitude faster than the previous method for the bulk ***, transport studies show that the nanoribbons are of low unintentional doping and high carrier mobility, over30000 cm2/V·s, which enable reliable determination of the Berry phase of π in the ac plane from quantum oscillations. Our method holds great potential in growth of high quality ultra-thin nanostructures of ZrTe5.

关键词： ZrTe5 nanoribbons growth chemical vapor transport mobility

Effects of growth temperature and metamorphic buffer on electron mobility of InAs film grown on Si substrate by molecular beam epitaxy

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Chinese Physics B 2019年第2期28卷 428-433页

作者： Jing Zhang Hongliang Lv Haiqiao Ni Shizheng Yang Xiaoran Cui Zhichuan Niu Yimen Zhang Yuming Zhang School of Microelectronics Xidian University and the State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences

The growth of the InAs film directly on the Si substrate deflected from the plane(100) at 4° towards(110) has been performed using a two-step procedure. The effect of the growth and annealing temperature on the electron mobility and surface topography has been investigated for a set of samples. The results show that the highest electron mobility is4640 cm^2/V·s in the sample, in which the 10-nm InAs nucleation layer is grown at a low temperature of 320 ℃ followed by ramping up to 560 ℃, and the nucleation layer was annealed for 15 min and the second layer of InAs is grown at 520 ℃.The influence of different buffer layers on the electron mobility of the samples has also been investigated, which shows that the highest electron mobility of 9222 cm^2/V·s at 300 K is obtained in the sample grown on a thick and linearly graded InGaAlAs metamorphic buffer layer deposited at 420 ℃.

关键词： InAs Si high electron mobility growth temperature InGaAlAs metamorphic buffer

Role of remote Coulomb scattering on the hole mobility at cryogenic temperatures in SOI p-MOSFETs

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Chinese Physics B 2020年第3期29卷 473-479页

作者： Xian-Le Zhang Peng-Ying Chang Gang Du Xiao-Yan Liu Institute of Microelectronics Peking UniversityBeijing 100871China

The impacts of remote Coulomb scattering(RCS)on hole mobility in ultra-thin body silicon-on-insulator(UTB SOI)p-MOSFETs at cryogenic temperatures are *** physical models including phonon scattering,surface roughness scattering,and remote Coulomb scatterings are considered,and the results are verified by the experimental results at different temperatures for both bulk(from 300 K to 30 K)and UTB SOI(300 K and 25 K)*** impacts of the interfacial trap charges at both front and bottom interfaces on the hole mobility are mainly evaluated for the UTB SOI p-MOSFETs at liquid helium temperature(4.2 K).The results reveal that as the temperature decreases,the RCS due to the interfacial trap charges plays an important role in the hole mobility.

关键词： remote Coulomb scattering hole mobility cryogenic temperatures UTB SOI p-MOSFETs

Significant enhancement of photoresponsive characteristics and mobility of MoS2-based transistors through hybridization with perovskite CsPbBr3 quantum dots

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Nano Research 2019年第2期12卷 405-412页

作者： Taeho Noh Heung Seob Shin Changwon Seo Jun Young Kim Jongwon Youn Jeongyong Kim Kwang-Sup Lee Jinsoo Joo Department of Physics Korea University Seoul 02841 Republic of Korea Department of Advanced Materials and Chemical Engineering Hannatn University Daejeon 34430 Republic of Korea Department of Energy Science Sungkyunkwan University Suwon 16419 Republic of Korea

Inorganic perovskite CsPbBr3 quantum dots (QDs) are potential nanoscale photosensitizers;moreover,two-dimensional (2-D) molybdenum disulfide (MoS2) has been intensively studied for application in the active layers of optoelectronic *** this study,heterostructures of 2D-monolayered MoS2 with zero-dimensional functionalized CsPbBr3 QDs were prepared,and their nanoscale optical characteristics were *** effect of n-type doping on the MoS2 monolayer after hybridization with perovskite CsPbBr3 QDs was observed using laser confocal microscope photoluminescenca (PL) and Raman ***-effect transistors (FETs) using MoS2 and the MoS2-CsPbBr3 QDs hybrid were also fabricated,and their electrical and photoresponsive characteristics were investigated in terms of the charge transfer *** the MoS2-CsPbBr3 QDs-based FETs,the field effect mobility and photoresponsivity upon light irradiation were enhanced by ~ 4 times and a dramatic ~ 17 times,respectively,compared to the FET prepared without the parovskite QDs and without light *** is noteworthy that the photoresponsivity of the MoS-2-CsPbBr3 QDs-based FETs significantly increased with increasing light power,which is completely contrary to the behavior observed in previous studies of MoS2-based *** increased mobility and significant enhancement of the photoresponsivity can be attributed to the n-type doping effect and efficient energy transfer from CsPbBr3 QDs to *** results indicate that the optoelectronic characteristics of MoS2-based FETs can be significantly improved through hybridization with photosensitive parovskite CsPbBr3 QDs.

关键词： MoS2 perovskite quantum dot transistor photoresponsivity mobility charge transfer

Towards high-mobility In2xGa2-2xO3 nanowire field-effecttransistors

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Nano Research 2018年第11期11卷 5935-5945页

作者： Ziyao Zhou Changyong Lan SenPo Yip Renjie Wei Dapan Li Lei Shu Johnny C. Ho Department of Materials Science and Engineering City University of Hong Kong Kowloon Hong Kong 999077 China School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu 610054 China Shenzhen Research Institute City University of Hang Kong Shenzhen S 18057 China State Key Laboratory of Millimeter Waves City University of Hang Kong Kowloon Hang Kong 999077 China

Recently, owing to the excellent electrical and optical properties, n-type In2O3 nanowires (NWs) have attracted tremendous attention for application in memory devices, solar cells, and ultra-violet photodetectors. However, the relatively low electron mobility of In2O3 NWs grown by chemical vapor deposition (CVD) has limited their further utilization. In this study, utilizing in-situ Ga alloying, highly crystalline, uniform, and thin In2xGa2−2xO3 NWs with diameters down to 30 nm were successfully prepared via ambient-pressure CVD. Introducing an optimal amount of Ga (10 at.%) into the In2O3 lattice was found to effectively enhance the crystal quality and reduce the number of oxygen vacancies in the NWs. A further increase in the Ga concentration adversely induced the formation of a resistive β-Ga2O3 phase, thereby deteriorating the electrical properties of the NWs. Importantly, when configured into global back-gated NW field-effect transistors, the optimized In1.8Ga0.2O3 NWs exhibit significantly enhanced electron mobility reaching up to 750 cm2·V–1·s–1 as compared with that of the pure In2O3 NW, which can be attributed to the reduction in the number of oxygen vacancies and ionized impurity scattering centers. Highly ordered NW parallel arrayed devices were also fabricated to demonstrate the versatility and potency of these NWs for next-generation, large-scale, and high-performance nanoelectronics, sensors, etc.

关键词： In 2 O 3 In 2 x Ga 2−2 x O 3 nanowire chemical vapor deposition mobility oxygen vacancy

Aging effect on the mobility and bioavailability of copper in soil

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Journal of Environmental Sciences 2009年第2期21卷 173-178页

作者： LU Anxiang ZHANG Shuzhen QIN Xiangyang WU Wenyong LIU Honglu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences P. O. Box 2871 Beijing 100085 China National Engineering Research Center for Information Technology in Agriculture P. O. Box 2449-26 Beijing 100097 China Beijing Hydraulic Research Institute Beijing 100044 China

Aging effect on the mobility and bioavallability of copper （Cu） was investigated using a spiked soil with different incubation periods from 3 to 56 d. Wheat was planted and earthworms were cultured separately in the incubated soils. The mobility of Cu in soil was evaluated by a chemical fractionation scheme and the toxicity and bioavailability were assessed by measuring the biomass and Cu concentration in tissues. Results showed that aging had a significant effect on Cu fraction distribution, of which Cu tended to incorporate from the exchangeable into more stable fractions such as the reducible and oxidisable fractions. However, aging had little effect on Cu bioavailability to wheat and earthworm. Comparing the soil being incubated for 3 d and 56 d, Cu concentration in wheat roots decreased from 14.5 to 12.8 mg/kg, and no significant changes in Cu concentration were observed in both wheat shoots and earthworms. The Cu concentration was around 2.0 and 50 mg/kg for wheat shoots and earthworms, respectively, irrespective of soil incubation time. The CaC12-extractable Cu had a linear relationship with Cu concentration in wheat roots （R2 = 0.65, P 〈 0.05）, but no linear relationship can be found for wheat shoots and earthworms. Biological control may be more crucial for Cu accumulation in organism than the changes in soil Cu fraction caused by aging.

关键词： aging effect copper mobility bioavailability

The low-temperature mobility of two-dimensional electron gas in AlGaN/GaN heterostructures

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Chinese Physics B 2008年第7期17卷 2689-2695页

作者：张金风毛维张进城郝跃 Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices Microelectronics InstituteXidian University

To reveal the internal physics of the low-temperature mobility of two-dimensional electron gas （2DEG） in Al- GaN/GaN heterostructures, we present a theoretical study of the strong dependence of 2DEG mobility on Al content and thickness of AlGaN barrier layer. The theoretical results are compared with one of the highest measured of 2DEG mobility reported for AlGaN/GaN heterostructures. The 2DEG mobility is modelled as a combined effect of the scat- tering mechanisms including acoustic deformation-potential, piezoelectric, ionized background donor, surface donor, dislocation, alloy disorder and interface roughness scattering. The analyses of the individual scattering processes show that the dominant scattering mechanisms are the alloy disorder scattering and the interface roughness scattering at low temperatures. The variation of 2DEG mobility with the barrier layer parameters results mainly from the change of 2DEG density and distribution. It is suggested that in AlGaN/GaN samples with a high Al content or a thick AlGaN layer, the interface roughness scattering may restrict the 2DEG mobility significantly, for the AlGaN/GaN interface roughness increases due to the stress accumulation in AlGaN layer.

关键词： two-dimensional electron gas mobility AlGaN/GaN heterostructures interface roughness