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空间索杆铰接式伸展臂参数设计与精度测量

光学精密工程 2010年第5期18卷 1105-1111页

作者：郭宏伟邓宗全刘荣强哈尔滨工业大学机器人技术与系统国家重点实验室黑龙江哈尔滨150080

结合空间索杆铰接式伸展臂在航天工程中的应用,基于伸展臂从航天器伸出且前端支撑负载的在轨工作状态,运用欧拉梁理论建立了悬臂式伸展臂理论分析模型。分析了工作状态下伸展臂与负载系统的固有频率和根部弯曲强度,提出了基于伸展臂固... 详细信息

结合空间索杆铰接式伸展臂在航天工程中的应用,基于伸展臂从航天器伸出且前端支撑负载的在轨工作状态,运用欧拉梁理论建立了悬臂式伸展臂理论分析模型。分析了工作状态下伸展臂与负载系统的固有频率和根部弯曲强度,提出了基于伸展臂固有频率限制和根部弯矩限制的伸展臂参数设计方法。通过算例分析了伸展臂线密度、半径、纵杆截面面积等主要设计参数与伸展臂固有频率和根部弯矩之间的关系。研制了伸展臂原理样机,其弯曲刚度和抗弯强度分别为0.388 MN.m2和562.12 N.m,验证了伸展臂具有较高的刚度和强度。对伸展臂物理样机的地面重复展开定位精度进行了测量实验,其轴向、水平、竖直方向上的重复展开精度分别为0.127 mm、0.645 mm和0.588 mm,证明了伸展臂具有较高的重复展开定位精度。

关键词：空间索杆铰接式伸展臂模型固有频率弯曲强度定位精度

Hybrid improper ferroelectricity and phase transition behavior of Li_(2)Nd_(2)Ti_(3)O_(10)ceramics with A-site ordered triple-layer Ruddlesden-Popper structure

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Journal of Materiomics 2024年第1期10卷 145-153页

作者： Bi Hui Zhang Diming Xu Rui Ze Guo Lu liu Xiao qiang liu Xiang Ming Chen Laboratory of Dielectric Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou310058China Key Laboratory of Multifunctional Materials and Structures Ministry of EducationSchool of Electronic Science and EngineeringXi'an Jiaotong UniversityXi'an710049China

Hybrid improper ferroelectricity has been extensively reported through theoretical prediction and experimental investigation in the oxides with Ruddlesden-Popper(R-P)***,the experimentally reported ferroelectric materials based on triple-layer R-P structures are rare,and the weak ferroelectricity impedes its practical *** the present work,the single-phase Li_(2)Nd_(2)Ti_(3)O_(10)ceramics with A-site cation ordered triple-layer R-P structure was obtained by spark plasma sintering technique,and the crystal structure of P2_(1)ab symmetry was revealed by neutron powder diffraction and transmission electron microscope ***,the switchable ferroelectricity in Li_(2)Nd_(2)Ti_(3)O_(10)ceramics has been observed at room temperature,and the saturated polarization-electric field hysteresis loop was obtained with P_(r)=0.4μC/cm^(2)under the electric field of 250 kV/*** phase transition behavior of Li_(2)Nd_(2)Ti_(3)O_(10)oxides was revealed by the temperature-dependence Raman and dielectric spectra combined with the piezoelectric property.

关键词： Hybrid improper ferroelectricity A-site ordered Ruddlesden-Popper structure Phase transition behavior

An injectable,self-healable,and reusable PEDOT:PSS/PVA hydrogel patch electrode for epidermal electronics

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Nano Research 2024年第6期17卷 5479-5490页

作者： Yang Li Yuzhe Gu Sheng Qian Shuwen Zheng Yuncong Pang Lele Wang Baoguang liu Shujuan liu qiang Zhao College of Electronic and Optical Engineering and College of Flexible Electronics(Future Technology) Nanjing University of Posts and Telecommunications(NJUPT)Nanjing 210023China State Key Laboratory of Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Nanjing University of Posts and Telecommunications(NJUPT)Nanjing 210023China

Injectability empowers conductive hydrogels to transcend traditional limitations,unlocking a realm of possibilities for innovative medical,wearable,and therapeutic applications that can significantly enhance patient care and quality of ***,we report an injectable,self-healable,and reusable hydrogel obtained by mixing the concentrated poly(3,4-ethylenedioxythiophene)doped with polystyrene sulfonate(PEDOT:PSS)suspension(~2 wt.%solid content),polyvinyl alcohol(PVA),and *** the presence of reversible borax/hydroxyl bonds and multiple hydrogen bonds,this PEDOT:PSS/PVA hydrogel exhibits notable shear-thinning behavior and self-healing capabilities,enabling it to be injected as a gel fiber from a ***-prepared injectable hydrogel also demonstrates an ultra-low modulus(~2.5 MPa),reduced on-skin impedance(~45%of commercial electrodes),and high signal-to-noise ratio(SNR)(~15-22 dB)in recording of electrocardiography(ECG),electromyography(EMG),and electroencephalogram(EEG)***,the injectable hydrogels can be remolded and reinjected as the reusable electrodes,maintaining nearly identical electrophysiological recording capabilities and brain-computer interface(BCI)performance compared to commercial wet *** their straightforward fabrication,excellent material properties and electronic performance,ease of cleaning,and remarkable reusability,our injectable PEDOT:PSS/PVA hydrogels hold promise for advancements in BCI based electronics and wearable bioelectronics.

关键词： epidermal hydrogel electrodes reusability injectability self-healing electrophysiological recording brain-computer interface

Study on Influencing Factors of Mental Health of Mobile Young White-Collar Workers in China

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International Journal of Mental Health Promotion 2024年第2期26卷 127-138页

作者： Tao liu Lin liu Zeyu Chen rong Fu Department of Sociology Hangzhou Dianzi UniversityHangzhou310018China College of Economics Hangzhou Dianzi UniversityHangzhou310018China

Mobile young white-collar workers not only have the characteristics of mobile young people,but also have the characteristics of general white-collar *** the influence of both,their mental health may be suffering from“double disadvantage”.So,based on an ecological model of the stress process,this paper tries to use the data of the questionnaire on the mental health of mobile young white-collar workers in Zhejiang Province to explore the influence of some factors in the middle workplace and residence place on the mental health of micro *** results show that:(1)The working environment with high control and low freedom and the workplace discrimination against the mobile status will have a negative impact on the mental health of mobile young white-collar workers;(2)Financial anxiety in daily life will lead to a decline in the mental health level of mobile young white-collar workers;(3)Good organizational support and neighborhood social relations can significantly relieve life pressure,so as to effectively improve the mental health of mobile young white-collar *** can be seen that we also need to pay more attention to the mental health of mobile young white-collar workers in order to improve their situation.

关键词： Mobile population young white-collar workers mental health ecological model stress process

Purification performance on molten steel of novel Al_(2)O_(3)-based ceramic filter prepared from microporous powder and nano-Al_(2)O_(3) powder

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Journal of Iron and Steel Research International 2024年第6期31卷 1535-1546页

作者： Zhe Chen Wen Yan Ying liu Guang-qiang Li Shao-song Hong Nan Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Jiangsu Shengnai New Materials Co. Ltd.Taizhou 225534JiangsuChina

Reticulated ceramic foam filters provide an effective way to purify molten steel by removing non-metallic *** proposed a novel strategy to improve the purification performance of Al_(2)O_(3)-based ceramic filters by using microporous corundum-spinel raw materials to replace dense raw *** kinds of Al_(2)O_(3)-based ceramic filters fabricated from dense α-Al_(2)O_(3) micro-powder or microporous corundum-spinel powder were selected to carry out the immersion tests with molten *** the one hand,the higher surface roughness of the filter skeleton prepared from microporous raw materials increased the adsorption capacity of skeleton surface on inclusions in molten *** the other hand,the higher apparent porosity and larger pore size of the filter skeleton were more beneficial to the penetration of molten steel in the micropores of *** reaction process at the solid-liquid interface also improved the wettability of the interface between skeleton and molten steel,resulting in a larger penetration depth and a better adsorption effect on the *** summary,the novel Al_(2)O_(3)-based ceramic filter prepared with microporous corundum-spinel powder and addition of 5 wt.% nano-Al_(2)O_(3) powder reduced the total oxygen content of the steel from 40.2×10^(-4) to 12.7×10^(-4) wt.% by 68.4% and the Al content from 0.46 to 0.18 wt.% by 60.9% after immersion test,presenting the most excellent purification performance on molten steel.

关键词： Al_(2)O_(3)-based ceramic filter Microporous corundum-spinel powder Non-metallic inclusion-Microstructure Molten steel purification

Simulating the GRF of Humanoid Robot Vertical Jumping Using a Simplified Model with a Foot Structure for Foot Design

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Journal of Bionic Engineering 2024年第1期21卷 112-125页

作者： Chuanku Yi Xuechao Chen Yu Zhang Zhangguo Yu Haoxiang Qi Yaliang liu qiang Huang School of Mechatronical Engineering Beijing Institute of TechnologyZizhuyaunHaidianBeijing 100081China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Tec

There are many theories and tools for human or robot motion simulation,but most of them require complex *** LNZN model(a simplified model named by the proposers)simplifies the human model and facilitates simulation of the Ground Reaction Force(GRF)of body landing by spring damping model and ignoring joint rotation movements,which can reduce the amount of computation *** this paper,the LNZN model of human running is selected as the basis and is modified to obtain the LNZN model of a robot,which expands the application of the LNZN *** to the structure of the human foot,a foot structure is then added to the simplified model to reduce the *** also applied driving forces to the new model to simulate the whole high jump motion of the robot to expand the functions of the LNZN *** obtained GRF data were anastomotic to the actual experimental *** addition,the effects of variables,such as the mass,hardness,and damping,of the foot on the GRF at the moment of landing were also ***,based on the guidelines obtained for the design of the robot’s foot structure,we fabricated new robot’s feet and installed them on the actual robot and achieved a better cushioning effect than the original foot in experiments.

关键词： LNZN model-GRF simulation Humanoid foot structure Foot parameters

Interpreting Larix principis-rupprechtii radial growth in northern China based on the Vaganov-Shashkin model

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Journal of Forestry Research 2024年第3期35卷 99-110页

作者： Jiachuan Wang Shuheng Li qiang Li Yili Guo Yijie Han Qi liu Yiqi Zhao College of Urban and Environmental Sciences Northwest UniversityXi'an 710127People's Republic of China Institute of Global Environmental Change Xi'an Jiaotong UniversityXi'an 710049People's Republic of China Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity Northwest UniversityXi'an 710127People's Republic of China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061People's Republic of China

Changes in annual radial growth is an important indication of climate change. Dendroclimatology studies in northern China have focused on linear statistical analysis,but lacking studies based on the process of ring formation to clarify the radial growth of trees. Tree-ring width standard chronology(STD) was established using samples of Larix principis-rupprechtii collected at 2303 m altitude on Luya Mountain. Using the Vaganov-Shashkin(VS) model to simulate growth and development, the internal physiological mechanism of radial growth is identified. It was concluded that:(1) the growing season of L. principis-rupprechtii was May to September;(2) soil moisture was a significant factor in the early and late growing seasons, and temperature was the dominant factor in its main growth period;and(3) formation of narrow ring widths was closely related to drought stress, the development of wide ring widths will be restricted by increasing future temperatures. The VS model is applicable for radial growth simulation of subalpine coniferous forests and for guiding the cultivation of local tree species in the future.

关键词： Vaganov-Shashkin model Larix principis-rupprechti Tree-ring width Annual growth

Perception-Driven Learning of High-Dynamic Jumping Motions for Single-Legged Robots

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Journal of Bionic Engineering 2024年第4期21卷 1733-1746页

作者： Nengxiang Sun Fei Meng Sai Gu Botao liu Xuechao Chen Zhangguo Yu qiang Huang School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100081China Key Laboratory of Biomimetic Robots and Systems Ministry of EducationBeijing100081China

Legged robots show great potential for high-dynamic motions in continuous interaction with the physical environment,yet achieving animal-like agility remains significant *** animals usually predict and plan their next locomotion by combining high-dimensional information from proprioception and exteroception,and adjust the stiffness of the body’s skeletal muscle system to adapt to the current *** control methods have limitations in handling high-dimensional state information or complex robot motion that are difficult to plan manually,and Deep Reinforcement Learning(DRL)algorithms provide new solutions to robot motioncontrol *** by biomimetics theory,we propose a perception-driven high-dynamic jump adaptive learning algorithm by combining DRL algorithms with Virtual Model Control(VMC)*** robot will be fully trained in simulation to explore its motion potential by learning the factors related to continuous jumping while knowing its real-time jumping *** policy trained in simulation is successfully deployed on the bio-inspired single-legged robot testing platform without further *** results show that the robot can achieve continuous and ideal vertical jumping motion through simple training.

关键词： Deep reinforcement learning High-dynamic jump Perception driven Single-legged robot

Pyruvate kinase M in germ cells is essential for sperm motility and male fertility but not spermatogenesis

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Asian Journal of Andrology 2024年第2期26卷 212-219页

作者： Gao-Qing Qian Xiao-Chen Wang Xi Zhang Bin Shen qiang liu State Key Laboratory of Reproductive Medicine and Offspring Health Nanjing Medical UniversityNanjing 211166China Shanghai Key Laboratory of Reproductive Medicine Department of HistoembryologyGenetics and Developmental BiologyShanghai Jiao Tong University School of MedicineShanghai 200025China State Key Laboratory of Molecular Biology Shanghai Key Laboratory of Molecular AndrologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghai 200031China

Male germ cells employ specific metabolic pathways throughout their developmental *** a previous study,we discovered heightened expression of pyruvate kinase M(PKM),a pivotal glycolytic enzyme,in spermatogonia and *** gain deeper insights into PKM's roles in spermatogenesis,sperm function,and male fertility,we engineered a conditional-knockout mouse model(Pkm-vkO mice)to selectively disrupt the Pkm gene within germ *** maintaining regular testicular histology and sperm morphology,the male Pkm-vko mice were infertility,characterized by significant impairments in sperm motility and adenosine triphosphate(ATP)*** addition,Pkm-null spermatozoa exhibited similar deficits in protein tyrosine phosphorylation linked to capacitation,as well as compromised performance in in vitro fertilization *** conclude,PKM's presence is not obligatory for the entirety of spermatogenesis in male germ cells;however,it emerges as a critical factor influencing sperm motility and overall male fertility.

关键词： glycolysis male fertility pyruvate kinase M sperm motility spermatogenesis