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Design and Cryogenic Performance of a Hexapod Platform for a Large Ground-based Wide Field Survey Telescope

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Research in Astronomy and Astrophysics 2024年第1期24卷 178-187页

作者： Yang Yu Xue-wen Wang Yu zhang Jia-lin Sun Zhen-Bang Xu Jian-Li Wang Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Chinese Academy of Sciences Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System Changchun 130033China University of Chinese Academy of Sciences Beijing 100049China

The thermal gradient is an important factor that causes degradation to the image quality of telescopes. In order to ensure the accurate alignment of the primary focus unit and the primary mirror, the hexapod platform(as a corrector) is investigated in this paper. First, a ground-based telescope with 2.5 m aperture and 3.5 deg field of view is described. The telescope is under construction, and it is expected to be finished in 2023. Second, the hexapod platform with flexure hinges utilized to adjust the primary focus unit is proposed, which is applied as a ***, the inverse kinematics of the platform is established and an open-loop control system is built based on ***, the cryogenic performance test for the hexapod platform is performed. The experimental results show that the resolution and repeatability of the translation for the hexapod platform can be achieved at the micrometer *** resolution and repeatability of the rotation can be achieved at the arc-second level. Therefore, the cryogenic performance of the hexapod platform can meet the optical imaging requirements of the wide-field ground-based telescope. The kinematic analysis and cryogenic performance tests in the paper provide a technical reference for the precise alignment of the primary focus unit and the primary mirror, which can improve the imaging quality of the telescope.

关键词： methods:miscellaneous space vehicles:instruments telescopes miscellaneous

Highly selective photocatalytic reduction of CO_(2) to CH_(4) on electron-rich Fe species cocatalyst under visible light irradiation

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Carbon Energy 2024年第1期6卷 255-266页

作者： Qianying lin Jiwu Zhao Pu zhang Shuo Wang Ying Wang Zizhong zhang Na wen Zhengxin Ding Rusheng Yuan Xuxu Wang Jinlin Long State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhouChina

Efficient photocatalytic reduction of CO_(2) to high-calorific-value CH4,an ideal target product,is a blueprint for C_(1)industry relevance and carbon neutrality,but it also faces great ***,we demonstrate unprecedented hybrid SiC photocatalysts modified by Fe-based cocatalyst,which are prepared via a facile impregnation-reduction method,featuring an optimized local electronic *** exhibits a superior photocatalytic carbon-based products yield of 30.0μmol g^(−1) h^(−1) and achieves a record CH_(4) selectivity of up to 94.3%,which highlights the effectiveness of electron-rich Fe cocatalyst for boosting photocatalytic performance and ***,the synergistic effects of directional migration of photogenerated electrons and strongπ-back bonding on low-valence Fe effectively strengthen the adsorption and activation of reactants and intermediates in the CO_(2)→CH_(4) *** study inspires an effective strategy for enhancing the multielectron reduction capacity of semiconductor photocatalysts with low-cost Fe instead of noble metals as cocatalysts.

关键词： artificial synthesis of CH_(4) electronic structure optimization Fe species cocatalyst photocatalytic CO_(2) reduction SiC

Evaluation of the clinical effects of atropine in combination with remifentanil in children undergoing surgery for acute appendicitis

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World Journal of Gastrointestinal Surgery 2024年第7期16卷 2065-2072页

作者： Yu-Juan Li Yong-Yan Chen Xia-Lan lin Wei-zhi zhang Department of Anesthesiology Shanxi Provincial Children’s HospitalTaiyuan 030013Shanxi ProvinceChina

BACKGROUND Acute appendicitis(AA)is the most common cause of acute abdomen in *** significantly influences the surgical treatment of AA in children,making the scientific and effective selection of anesthetics *** To assess the clinical effect of atropine(ATR)in combination with remifentanil(REMI)in children undergoing surgery for *** In total,108 cases of pediatric AA treated between May 2020 and May 2023 were selected,58 of which received ATR+REMI[research group(RG)]and 50 who received REMI[control group(CG)].Comparative analyses were conducted on the time to loss of eyelash reflex,pain resolution time,recovery time from anesthesia,incidence of adverse events(AEs;respiratory depression,hypoxemia,bradycardia,nausea and vomiting,and hypotension),intraoperative responses(head shaking,limb activity,orientation recovery,safe departure time from the operating room),hemodynamic parameters[oxygen saturation(SPO2),mean arterial pressure,heart rate,and respiratory rate],postoperative sedation score(Ramsay score),and pain level[the Face,Legs,Activity,Cry,Consolability(FLACC)Behavioral Scale].RESULTS Compared with the CG,the RG showed significantly shorter time to loss of eyelash reflex,pain resolution,recovery from anesthesia,and safe departure from the operating ***,the incidence rates of overall AEs(head shaking,limb activity,etc.)were lower,and influences on intraoperative hemodynamic parameters and stress response indexes were *** Ramsay score at 30 min after extubation and the FLACC score at 60 min after extubation were significantly lower in the RG than in the *** ATR+REMI is superior to REMI alone in children undergoing AA surgery,with a lower incidence of AEs,fewer influences on hemodynamics and stress responses,and better post-anesthesia recovery.

关键词： Atropine Remifentanil Pediatric acute appendicitis Surgery Clinical efficacy

Methane adsorption effected by pore structure of overmature continental shale:Lower Cretaceous Shahezi Formation,Xujiaweizi Fault,Songliao Basin

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Frontiers of Earth Science 2024年第1期18卷 172-187页

作者： Pengfei zhang Shuangfang LU Nengwu ZHOU Zizhi lin xiangchun CHANG Junjian zhang Guo CHEN Yumao PANG Junjie WANG Hongsheng HUANG Qi zhi College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya 572025China School of Geoscience China University of Petroleum(East China)Qingdao 266580China College of Resources and Environment Yangtze UniversityWuhan 430100China

Overmature continental shale is commonly developed,but few studies have given insight into its pore structure and sorption *** techniques,including SEM,helium porosity and permeability,N_(2)/CO_(2)adsorption,MICP,and NMR,were used to detect the pore structure of shale from the Shahezi Formation,Xujiaweizi Fault,Songliao *** excess methane adsorption volumes were measured by the volumetric method and modeled by the Langmuir *** on the findings,the most developed pores are intraparticle pores in clay minerals,followed by the dissolution pores in feldspar,but organic pores are *** selected shales have low helium porosity(mean 1.66%)and ultralow permeability(mean 0.0498×10^(−3)μm^(2)).The pore throats are at the nanoscale,and the pore-throat size distributions are unimodal,with most less than 50 *** studied shales are characterized by the lower specific surface area(SSA)and pore volume(PV)but the larger average pore *** total SSA is contributed by the micro-and mesopores,while the PV is dominated by meso-and *** pore structures are more complex and controlled by multiple factors,such as mineral compositions and diagenesis,but organic matter is not *** maximum absolute adsorption methane volume(VL)is 0.97−3.58 cm^(3)/g(mean 1.90 cm^(3)/g),correlating well with the total SSA,SSA,and pore volume of micropores,which indicates that methane is mainly adsorbed and stored in micropores,followed by mesopores.

关键词： continental shale pore structure methane adsorption Shahezi Formation Songliao Basin

Lithium-induced graphene layer containing Li_(3)P alloy phase to achieve ultra-stable electrode interface for lithium metal anode

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Rare Metals 2024年第2期43卷 562-574页

作者： Jia-Xin Chen Guo-Qiang zhang Xian-Ying qin Kui lin Zi-Jin Yang Ge-Meng Liang Yue Xia Guo-Bin zhang Hai-Kun Wu Qiu-Chan Cai Hai lin Bao-Hua Li Shenzhen Key Laboratory on Power Battery Safety Research and Shenzhen Geim Graphene Center Tsinghua Shenzhen International Graduate SchoolShenzhen518055China Shenzhen Graphene Innovation Center Co. Ltd.Shenzhen518107China School of Chemical Engineering and Advanced Materials The University of AdelaideAdelaideSA5005Australia Department of Chemistry City University of Hong KongHong Kong990077China

Uncontrolled growth of lithium dendrite will lead to low Coulombic efficiency and poor cycle stability,which hinders the commercialization of lithium metal ***,a novel modified lithium anode with reduced graphene oxide conductive network containing trace lithiophilic phosphorus(P-rGO/Cu)is prepared by electrospraying technique combined with heat treatment *** rGO layer has a concave and undulating conductive structure,which can significantly improve the effective electrical contact between lithium metal and the current collector,speed up the kinetics of interfacial electron transport and reaction,and improve the resistance of the negative electrode to the internal stress caused by volume change of the lithium,which is advantageous for the stability of the SEI *** extremely small and uniformly distributed red phosphorus element avoids the volume change caused by lithiation to the maximum *** two-phase compound Li_(3)P obtained by alloying P with Li can directionally induce the homogeneous nucleation and dense deposition of lithium metal,address the issue of lithium dendrites and extend the cycle life of the *** obtained P-rGO/Cu exhibits excellent electrochemical performance with an average Coulombic efficiency(CE)of 98%at a current density of 1 mA·cm^(−2) for 400 cycles,and the capacity retention rate of the full cell matched with lithium iron phosphate(LFP)is 83%after 400 cycles at 1C.

关键词： Lithium anode Dendrite-free Lithiophilicity Induced nucleation deposition

Leukocyte cell-derived chemotaxin 2(LECT2)regulates liver ischemia-reperfusion injury

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Liver Research 2024年第3期8卷 165-171页

作者： Meng-Qi Dong Yuan Xie zhi-Liang Tang Xue-wen Zhao Fu-Zhen lin Guang-Yu zhang zhi-Hao Huang zhi-Min Liu Yuan lin Feng-Yong Liu Wei-Jie Zhou State Key Laboratory of Organ Failure Research Department of General SurgeryGuangdong Provincial Key Laboratory of Precision Medicine for Gastrointestinal TumorNanfang HospitalSouthern Medical UniversityGuangzhouGuangdongChina Department of Hepato-Biliary-Pancreatic and Hernia Surgery The First People's Hospital of ZhaoqingZhaoqingGuangdongChina Department of Interventional Radiology Senior Department of OncologyFifth Medical Center of PLA General HospitalBeijingChina

Background and aim Hepatic ischemia–reperfusion injury(IRI)is a significant challenge in liver transplantation,trauma,hypovolemic shock,and hepatectomy,with limited effective interventions *** study aimed to investigate the role of leukocyte cell-derived chemotaxin 2(LECT2)in hepatic IRI and assess the therapeutic potential of Lect2-short hairpin RNA(shRNA)delivered through adeno-associated virus(AAV)*** and methods This study analyzed human liver and serum samples from five patients undergoing the Pringle ***2-knockout and C57BL/6J mice were *** IRI was induced by clamping the hepatic *** included recombinant human LECT2(rLECT2)and ***2 expression levels and serum biomarkers including alanine aminotransferase(ALT),aspartate aminotransferase(AST),creatinine,and blood urea nitrogen(BUN)were *** analysis of liver necrosis and quantitative reverse-transcription polymerase chain reaction were *** Serum and liver LECT2 levels were elevated during hepatic *** LECT2 protein and mRNA levels increased post ***2-knockout mice had reduced weight loss;hepatic necrosis;and serum ALT,AST,creatinine,and BUN ***2 treatment exacerbated weight loss,hepatic necrosis,and serum biomarkers(ALT,AST,creatinine,and BUN).AAV-Lect2-shRNA treatment significantly reduced weight loss,hepatic necrosis,and serum biomarkers(ALT,AST,creatinine,and BUN),indicating therapeutic *** Elevated LECT2 levels during hepatic IRI increased liver *** knockout or shRNA-mediated knockdown of Lect2 reduced liver damage,indicating its therapeutic ***-mediated Lect2-shRNA delivery mitigated hepatic IRI,offering a potential new treatment strategy to enhance clinical outcomes for patients undergoing liver-related surgeries or trauma.

关键词： Hepatic ischemia-reperfusion injury(IRI) Leukocyte cell-derived chemotaxin 2 (LECT2) Adeno-associated virus(AAV)

Prediction of contact resistance of electrical contact wear using different machine learning algorithms

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Friction 2024年第6期12卷 1250-1271页

作者： Zhen-bing CAI Chun-lin LI Lei YOU Xu-dong CHEN Li-ping HE Zhong-qing CAO zhi-nan zhang Tribology Research Institute Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China

H62 brass material is one of the important materials in the process of electrical energy transmission and signal transmission,and has excellent performance in all *** the wear behavior of electrical contact pairs is particularly complex when they are in service,we evaluated the effects of load,sliding velocity,displacement amplitude,current intensity,and surface roughness on the changes in contact *** learning(ML)algorithms were used to predict the electrical contact performance of different factors after wear to determine the correlation between different factors and contact *** forest(RF),support vector regression(SVR)and BP neural network(BPNN)algorithms were used to establish RF,SVR and BPNN models,respectively,and the experimental data were trained and *** was proved that BP neural network model could better predict the stable mean resistance of H62 brass alloy after *** analysis shows that the load and current have great influence on the predicted electrical contact *** wear behavior of electrical contacts is influenced by factors such as load,sliding speed,displacement amplitude,current intensity,and surface roughness during *** learning algorithms can predict the electrical contact performance after wear caused by these *** results indicate that an increase in load,current,and surface roughness leads to a decrease in stable mean resistance,while an increase in displacement amplitude and frequency results in an increase in stable mean resistance,leading to a decline in electrical contact *** reduce testing time and costs and quickly obtain the electrical contact performance of H62 brass alloy after wear caused by different factors,three algorithms(random forest(RF),support vector regression(SVR),and BP neural network(BPNN))were used to train and test experimental results,resulting in a machine learning model suitable for predicting the stable mean

关键词： electrical contact wear contact resistance machine learning(ML) neural network

Dual-curvilinear beam enabled tunable manipulation of high-and low-refractive-index particles

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Photonics Research 2024年第7期12卷 1427-1436页

作者： ZHENG YUAN CHENCHEN zhang YUAN GAO wenxiang YAN XIAN LONG zhi-CHENG REN XI-lin WANG JIANPING DING HUI-TIAN WANG National Laboratory of Solid State Microstructures and School of Physics Nanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China Collaborative Innovation Center of Solid-State Lighting and Energy-Saving Electronics Nanjing 210093China

We present an innovative approach for the simultaneous agile manipulation of high-refractive-index(HRI) and low-refractive-index(LRI) particles. Our method involves introducing a dual-curvilinear optical vortex beam(DC-OVB) generated by superimposing a pair of curved beams: HRI and LRI particles are controlled by the bright curve and the dark channel between the two curves, respectively. The proposed DC-OVB provides customizable motion paths and velocities for both LRI and HRI particles. Each curve of the DC-OVB can support a distinct orbital flow density(OFD), enabling the application of torques to HRI and LRI particles, guiding them to orbit along specified trajectories and prompting them to execute various curvilinear motions simultaneously,including curvilinear movement, revolution, and rotation.

关键词： tunable refractive beam

The Active Compensation Technique for Large Reflector Antennas Based on Quadratic Curve Fitting

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Research in Astronomy and Astrophysics 2024年第7期24卷 226-234页

作者： Tian-xiang Zheng Bin-Bin xiang Han-Wei Cui Wei Wang Pei-Yuan Lian Shang-Ming lin Yang zhang Jian-Ping Zhou Kai Li School of Mechanical Engineering Xinjiang UniversityUrumqi 830017China School of Mechano-Electronic Engineering Xidian UniversityXi’an 710017China Xi’an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi’an 710119China

Active reflectors are often used to compensate the surface distortion caused by environmental factors that degrade the electromagnetic performance of large high-frequency reflector *** is crucial for maintaining high gain operation in antennas.A distortion compensation method for the active reflector of a large dual-reflector antenna is proposed.A relationship is established between the surface deformation and the optical path difference for the primary reflector by geometric ***,employing finite element analysis,a polynomial fitting approach is used to describe the impact of adjusting points on the reflector surface based on the coordinates of each *** standardizing the positions of various panels on the reflector,the fitting ns can be applied to the reflector panels of similar ***,based on the distribution characteristics of the primary reflector panels,the adjustment equation for the actuators is derived by the influence matrix *** can be used to determine the adjustment amount of actuators to reduce the rms of the optical path ***,the least squares method is employed to resolve the matrix *** example of a 110 m aperture dual-reflector antenna is carried out by finite element analysis and the proposed *** results show that the optical path difference is reduced significantly at various elevation cases,which indicates that the proposed method is effective.

关键词： Methods analytical-Methods numerical-Telescopes