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Unknown system dynamics estimator-based impedance control for lower limb exoskeleton with enhanced performance

Control Theory and Technology 2024年第1期22卷 56-68页

作者： Wenhao Zhang Peng Song Mingying Wu Qiang Li Xinmin mo Pingxin Ji Northwest institute of Mechanical and Electrical Engineering Xianyang712099ShaanxiChina Xi’an Exo-Smart Dynamics Technology Ltd. Xi’an712046ShaanxiChina department of Mechanical and Engineering Beijing Institute of TechnologyBeijing100081China

in this article, an unknown system dynamics estimator-based impedance control method is proposed for the lower limb exoskeleton to stimulate the tracking flexibility with the terminal target position when suffering parametric inaccuracies and unexpected disturbances. To reinforce the robust performance, via constructing the filtering operation-based dynamic relation, i.e., invariant manifold, the unknown system dynamics estimators are employed to maintain the accurate perturbation identification in both the hip and knee subsystem. Besides, a funnel control technique is designed to govern the convergence process within a minor overshoot and a higher steady-state precision. Meanwhile, an interactive complaint result can be obtained with the aid of the impedance control, where the prescribed terminal trajectory can be adjusted into the interaction variable-based target position by the force–position mapping, revealing the dynamic influence between the impedance coefficient (stiffness and damping) and the adjusted position magnitude. A sufficient stability analysis verifies the ultimately uniformly bounded results of all the error signals, and even the angle errors can be regulated within the predefined funnel boundary in the whole convergence. finally, some simulations are provided to demonstrate the validity and superiority including the enhanced interaction flexibility and robustness.

关键词： Trajectory tracking invariant manifold funnel control impedance control Lower limb exoskeleton

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development and parentage analysis of SNP markers for Chestnut-vented Nuthatch(Sitta nagaensis)based on ddRAD-seq data

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Avian Research 2024年第2期15卷 271-278页

作者： Qingmiao Yuan Xi Lu Ruixin mo Xianyin Xu Xu Luo Yubao Duan Key Laboratory for Conserving Wildlife with Small Populations in Yunnan Southwest Forestry UniversityKunming 650224China Key Laboratory for forest Resources Conservation and Utilization in the Southwest mountains of China Ministry of EducationSouthwest Forestry UniversityKunming 650224China Key Laboratory of forest Disaster Warning and Control of Yunnan Province Southwest Forestry UniversityKunming 650224China College of forestry Southwest Forestry UniversityKunming 650224China Administration of Zixi mountain Provincial Nature Reserve Chuxiong 675008China

Extra-pair paternity(EPP)is commonly found in socially monogamous birds,especially in small passerine birds,and there are interspecific and intraspecific variations in the extent of *** Chestnut-vented Nuthatch(Sitta nagaensis)is a socially monogamous passerine bird,and verifying whether this species has EPP relies on parentage *** is not known to have *** this study,we developed SNP markers of this species that are informative for parentage analysis from double digest restriction site-associated DNA sequencing(ddRAD-seq)data.A panel consisting of 50 SNP markers,with a mean heterozygosity of 0.343,was used to resolve 95% of nestlings to *** combined exclusion probabilities for the first parent and second parent were 0.991 and 0.9999,*** panel of SNP markers is a powerful tool for parentage assignments in *** addition,we found that three offspring(7.9%)from three nests(23.1%)were the result of extra-pair fertilization out of 38 offspring in 13 *** study provided information on parentage analysis that has not been reported before in *** also supplemented the understudied EPP behavior of birds in Asia,contributing to a general understanding of the EPP behaviors of birds.

关键词： Chestnut-vented Nuthatch ddRAD sequencing Extra-pair paternity Parentage analysis SNPs

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Policy uncertainty and land transaction prices in China

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Economic and Political Studies 2024年第2期12卷 117-142页

作者： Xiaoyang Li mo Liang Jidong Yang School of Accounting and finance The Hong Kong Polytechnic UniversityHong Kong SARChina School of finance Renmin University of ChinaBeijingChina School of Economics Renmin University of ChinaBeijingChina

Economic policy uncertainty has prominent effects on investment and *** unique transaction-level data in China,this paper explores the impact of economic policy uncertainty on land transaction premiums in *** average,a 1%increase in the policy uncertainty level reduces land transaction premiums by 3.907 percentage *** impact of policy uncertainty is more profound for firms with tighter financial constraints and land located in cities with lower rent-to-price *** influence of policy uncertainty becomes weaker after the anti-corruption campaign in China,especially in provinces scrutinised by the central inspection teams,implying that improvements in the political environment alleviates the impact of policy uncertainty.

关键词： Policy uncertainty land transaction price premium anti-corruption campaign

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Chinese expert consensus on an innovative patient‐centered approach to diagnosis and treatment of cancer

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Cancer innovation 2024年第5期3卷 50-70页

作者： Hongnan mo Ruiqi Zhong fei Ma department of Medical Oncology National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina +4 Medical Doctor Program Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijingChina

Patient‐centered care(PCC)is an innovative approach to the diagnosis and treatment of malignancy that aims to improve patients'experience during the management of their ***,despite growing interest,the concept and specifics of PCC remain *** consensus document addresses this gap by providing a literature review and a clear definition of PCC and outlines its main components as observed in real‐world *** components include daytime diagnostic and treatment procedures,in‐hospital and community‐based infusion centers,home‐based diagnostic and treatment services,smart healthcare solutions,and integration of traditional Chinese *** document delves into the implementation of PCC and explores its potential benefits.

关键词： cancer consensus management patient‐centered care quality of life

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Refined acoustic holography via nonlocal metasurfaces

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 113-123页

作者： Shuhuan Xie Hongyu Ma Junmei Cao fangshuo mo Qian Cheng Yong Li Tong Hao institute of Acoustics School of Physics Science and EngineeringTongji UniversityShanghai 200092China Center for Spatial information Science and Sustainable development Applications Tongji UniversityShanghai 200092China College of Surveying and Geo-informatics Tongji UniversityShanghai 200092China

Holography can provide the desired wavefront phase and/or amplitude for imaging,particle manipulation,bacteria trapping,and cell patterning in optics and ***,previous work on acoustic holography is mostly based on local design optimization,either using active control of the sound source or relying on the structural design to provide the desired *** precise control over the acoustic field remains a significant ***,we realize refined single-plane symmetric binary amplitude,asymmetric intensity gradient amplitude,and bi-objective hologram through the non-local holographic imaging theory that considers the acoustic coupling of structural units in *** taking into account the self-radiation and mutual radiation between many small units on a plate of well-designed thickness,as well as the transmission through the plate's apertures,we can effectively regulate the sound field behind the *** demonstrate the effectiveness of our approach through numerical simulations and experiments,showcasing a circle,a black hole,and a bi-objective with a circle and a square ***,the acoustic black hole hologram precisely reconstructs the intensity gradient distribution at two bright *** non-local holographic imaging theory is valuable for the fine-intensity regulation of the sound field and is expected to be applied in ultrasound diagnosis and treatment,medical imaging,and other fields.

关键词： acoustic holograms non-local interactions fine intensity modulation acoustic metasurfaces

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Effects of synthesis parameters on the performance of crosslinked Co-polymers with clays for conformance control

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Petroleum Research 2024年第1期9卷 98-108页

作者： A.A.Roslan N.A.A.Aziz N.f.A.deraman i.Dzulkarnain Petroleum Engineering department Centre of Research Enhanced Oil Recovery(COREOR)Universiti Teknologi PETRONASSeri IskandarPerakMalaysia Chemical Engineering department Centre of Research Enhanced Oil Recovery(COREOR)Universiti Teknologi PETRONASSeri IskandarPerakMalaysia

Conformance control or water shut-off is a technique used to improve oil *** conformance control,polymers block high permeability water areas and redistribute water drive toward unswept oil *** this study,co-polymers(denoted ATP-PGV/AM-co-AMPS)were synthesized using acrylamide(AM)and 2-acrylamide-2-methylpropane sulfonic acid(AMPS)as the monomers,polyethylene glycol(PEG)-200 and methylenebisacrylamide(MBA)as the crosslinkers,attapulgite(ATP)and bentonite(PGV)as the clay types,and ammo.ium persulfate(APS)as the initiator,in addition to paraffin oil and *** were synthesized using inverse emulsion polymerization with different concentrations of monomers,crosslinkers,and clays,and they were characterized using fourier-transform infrared(fTiR)spectroscopy and scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EDX).fTiR spectra of the samples confirmed the existence of sulfonate and hydroxyl groups,which are important for polymer ***-EDX images indicated that the morphology and elemental composition were different before and after swelling,confirming the occurrence of ***,samples were placed in sodium chloride solution(20,000 ppm)for 7 days to evaluate swelling at both room temperature and 90°*** analysis(TGA)and differential scanning calorimetry(DSC)were used to determine the thermal characteristics of the ***,rheological measurements were used to assess the deformation and rheological behavior of the *** results showed that after 1 day,good swelling without loss of mechanical strength was achieved with the composite synthesized using 10%AM,15%AMPS,6%PGV,and 10%ATP.

关键词： Polymer Clay Water shut-off Conformance Swelling

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Coupled CfD-deM Numerical Simulation of the interaction of a flow-Transported Rag with a Solid Cylinder

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fluid Dynamics & Materials Processing 2024年第7期20卷 1593-1609页

作者： Yun Ren Lianzheng Zhao Xiaofan mo Shuihua Zheng Youdong Yang Zhijiang College Zhejiang University of TechnologyShaoxing312030China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou310032China

A coupled Computational fluid Dynamics-Discrete Element Method(CfD-deM)approach is used to calculate the interaction of a flexible rag transported by a fluid current with a fixed solid *** specifically a hybrid Eulerian-Lagrangian approach is used with the rag being modeled as a set of interconnected *** influence of various parameters is considered,namely the inlet velocity(1.5,2.0,and 2.5 m/s,respectively),the angle formed by the initially straight rag with the flow direction(45°,60°and 90°,respectively),and the inlet position(90,100,and 110 mm,respectively).The results show that the flow rate has a significant impact on the permeability of the *** higher the flow rate,the higher the permeability and the rag speed *** angle has a minor effect on rag permeability,with 45°being the most favorable angle for *** inlet position has a small impact on rag permeability,while reducing the initial distance between the rag an the cylinder makes it easier for rags to pass through.

关键词： Rag flow around cylinder flow characteristics numerical simulation

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Precise immo.ilization of metal single atoms into a porphyrinic metal-organic framework for an efficient alkene hydrosilylation

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Nano Research 2024年第7期17卷 5914-5921页

作者： Chun-Ying Chen Qi-Jie mo fu-Zhen Li Hai-Li Song Li Zhang moE Laboratory of Bioinorganic and Synthetic Chemistry Lehn Institute of Functional MaterialsSchool of ChemistrySun Yat-Sen UniversityGuangzhou 510006China

Alkene hydrosilylation is one of the most concise and atom-economical methods to synthesize organosilicon ***,we reported the precise immo.ilization of metal single atoms(M-SAs;M=Ru,Rh,ir,Pd,Pt,and Au)into a porphyrinic metalorganic framework(mof)of PCN-222(PCN=porous coordination network),and then applied the resultant mof composites of M-SAs@PCN-222 to alkene *** solvent-free conditions,Pt-SAs@PCN-222 displayed an especially high catalytic efficiency with the turnover frequency up to 119 s−1 and the maximum turnover number of 906,250 at room *** and theoretical studies revealed that there existed strong interactions between Pt-SAs@PCN-222 and the substrates,which helped to condense the substrates in the cavities of the porous *** density functional theory calculations and molecular dynamics simulations disclosed that PCN-222 could transfer electrons to Pt-SAs to enhance the silane oxidative addition and drive the reaction to proceed smoothly via Chalk–Harrod pathway.

关键词： alkene hydrosilylation single atom catalysts metal-organic frameworks precision chemistry synergistic catalysis

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impact of oxaliplatin and trastuzumab combination therapy on tumor markers and T lymphocyte subsets for advanced gastric cancer

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World Journal of Gastrointestinal Oncology 2024年第9期16卷 3905-3912页

作者： Cheng-Wan Zheng Yun-mo Yang Hui Yang department of Thyroid Surgery The Affiliated Hospital of Southwest Medical UniversityLuzhou 646000Sichuan ProvinceChina

BACKGROUND Advanced gastric cancer(AGC)remains a challenging malignancy with poor *** combination of oxaliplatin and trastuzumab has shown promising results in AGC *** study aimed to investigate the effects of oxaliplatin and trastuzumab combination therapy on serum tumor markers and T lymphocyte subsets in patients with AGC and to explore their potential as predictive biomarkers for treatment *** To investigate the impact of oxaliplatin and trastuzumab combination therapy on serum markers and T cell subsets in patients with *** This prospective study enrolled 60 patients with *** patients received oxaliplatin(130 mg/m^(2),every 3 weeks)and trastuzumab(8 mg/kg loading dose,followed by 6 mg/kg every 3 weeks)for six *** carcinoembryonic antigen(CEA),cancer antigen 19-9(CA19-9),and cancer antigen 72-4(CA72-4)were measured before and after treatment.T-lymphocyte subsets,including CD3+,CD4+,CD8+,and CD4+/CD8+ratios,were also *** clinical response was assessed using the Response Evaluation Criteria in Solid Tumors version *** After six cycles of treatment,the CEA,CA19-9,and CA72-4 serum levels significantly decreased compared to baseline levels(Pf CD3+and CD4+T lymphocytes increased significantly(Pf CD8+T lymphocytes decreased(Pio also significantly increased after treatment(Pients with a higher decrease in serum tumor markers(≥50%reduction)and a higher increase in CD4+/CD8+ratio(≥1.5-fold)showed better clinical response rates(PiON Oxaliplatin and trastuzumab combination therapy effectively reduced serum tumor marker levels and modulated T lymphocyte subsets in patients with *** therapy not only has a direct antitumor effect,but also enhances the immune response in patients with *** tumor markers and T lymphocyte subsets may serve as potential predictive biomarkers for treatment respon

关键词： Advanced gastric cancer Oxaliplatin Trastuzumab Serum tumor markers T lymphocyte subsets Predictive biomarkers

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The effect of friction block hole configurations on the brake tribological performance of high-speed trains

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friction 2024年第10期12卷 2241-2258页

作者： Yuanke WU Wei CHEN Youguang ZHU Zaiyu XiANG Honghua QiAN Jiliang mo Zhongrong ZHOU Tribology Research institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China China Railway Engineering Equipment Group Co. Ltd.Zhengzhou 450016China

Three triangular friction block configurations are commonly employed in high-speed train brake systems,namely,unperforated,perforated configuration with one circular hole,and perforated with three circular *** this study,we adopted these friction block types to investigate the effect of perforated friction block configurations on the brake performance of high-speed trains based on a self.developed brake test *** results indicate the significant impact of the number of the holes on the wear behavior,temperature distribution,and vibration characteristics of the brake *** friction surface of the unperforated block is covered by wear debris,while the perforated blocks produce less wear ***,the one-hole block exhibits a more uniform temperature distribution and better vibration behavior than that with three *** friction brake is a dynamic process,during which separation and attachment between the pad and disc alternatively occur,and the perforated structure on the friction block can both trap and expel the wear debris.

关键词： high-speed train block brake performance wear debris flow

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