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Science china(Information Sciences) 2024年第7期67卷 224-239页

作者： Zhijia ZHAO Jiale WU Zhijie LIU We HE c.L.Philip chen School of Mechanical and Electrical Engineering Guangzhou University School of Intelligence Science and Technology and Key Laboratory of Intelligent Bionic Unmanned Systems of Ministry of Education University of Science and Technology Beijing School of computer Science and Engineering South China University of Technology Pazhou Lab

In this study, an adaptive neural network(NN) control is proposed for nonlinear two-degree-offreedom(2-DOF) helicopter systems considering the input constraints and global prescribed ***, radial basis function NN(RBFNN) is employed to estimate the unknown dynamics of the helicopter system. Second, a smooth nonaffine function is exploited to approximate and address nonlinear constraint functions. Subsequently, a new prescribed function is proposed, and an original constrained error is transformed into an equivalent unconstrained error using the error transformation and barrier function transformation methods. The analysis of the established Lyapunov function proves that the controlled system is globally uniformly bounded. Finally, the simulation and experimental results on a constructed Quanser's test platform verify the rationality and feasibility of the proposed control.

关键词： adaptive NN control 2-DOF helicopter global prescribed performance input constraints

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Mechanistic insight into cr(Ⅵ)retention by Si-containing ferrihydrite

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Journal of Environmental Sciences 2024年第5期139卷 217-225页

作者： Ying Hu Qiang Xue Honghan chen Huaming Guo Kenneth c.carroll Song Wang MOE Key Laboratory of Groundwater circulation and Environmental Evolution School of Water Resources and EnvironmentChina University of Geosciences(Beijing)Beijing 100083China Beijing Key Laboratory of Water Resources and Environmental Engineering School of Water Resources and EnvironmentChina University of GeosciencesBeijing 100083China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesBeijing 100083China Plant&Environmental Science New Mexico State UniversityNM 88003USA Institute of Theoretical chemistry College of ChemistryJilin UniversityChangchun 130023China

Hexavalent chromium[cr(Ⅵ)]causes serious harm to the environment due to its high toxicity,solubility,and ***(Fh)are the main adsorbent and trapping agent of cr(Ⅵ)in soils and aquifers,and they usually coexist with silicate(Si),forming Si-containing ferrihydrite(Si-Fh)***,the mechanism of cr(Ⅵ)retention by Si-Fh mixtures is poorly *** this study,the behaviors and mechanisms of cr(Ⅵ)adsorption onto Si-Fh with different Si/Fe molar ratios was *** electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and other techniques were used to characterize Si-Fh and cr(Ⅵ)-loading of *** results show that specific surface area of Si-Fh increases gradually with increasing Si/Fe ratios,but cr(Ⅵ)adsorption on Si-Fh decreases with increasing Si/Fe *** is because with an increase in Si/Fe molar ratio,the point of zero charge of Si-Fh gradually decreases and electrostatic repulsion between Si-Fh and cr(Ⅵ)***,the complexation of cr(Ⅵ)is enhanced due to the increase in adsorbed hydroxyl(A-OH-)on Si-Fh with increasing Si/Fe molar ratio,which partly counteracts the effect of the electrostatic ***,the increase in the electrostatic repulsion has a greater impact on adsorption than the additional complexation with *** functional theory calculation further supports this observation,showing the increases in electron variation of bonding atoms and reaction energies of inner spherical complexes with the increase in Si/Fe ratio.

关键词： Hexavalent chromium Ferrihydrite Si/Fe ratio cr(Ⅵ)Adsorption

Liquefaction susceptibility and deformation characteristics of saturated coral sandy soils subjected to cyclic loadings-a critical review

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 261-296页

作者： chen Guoxing Qin You Ma Weijia Liang Ke Wu Qi c.Hsein Juang Institute of Geotechnical Engineering Nanjing Tech UniversityNanjing 210009China civil Engineering and Earthquake Disaster Prevention center of Jiangsu Province Nanjing 210009China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China college of civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 210016China Glenn Department of civil Engineering Clemson UniversityClemsonSC 29634USA

coral sandy soils widely exist in coral island reefs and seashores in tropical and subtropical *** to the unique marine depositional environment of coral sandy soils,the engineering characteristics and responses of these soils subjected to monotonic and cyclic loadings have been a subject of intense interest among the geotechnical and earthquake engineering *** paper critically reviews the progress of experimental investigations on the undrained behavior of coral sandy soils under monotonic and cyclic loadings over the last three *** focus of coverage includes the contractive-dilative behavior,the pattern of excess pore-water pressure(EPWP)generation and the liquefaction mechanism and liquefaction resistance,the small-strain shear modulus and strain-dependent shear modulus and damping,the cyclic softening feature,and the anisotropic characteristics of undrained responses of saturated coral sandy *** particular,the advances made in the past decades are reviewed from the following aspects:(1)the characterization of factors that impact the mechanism and patterns of EPWP build-up;(2)the identification of liquefaction triggering in terms of the apparent viscosity and the average flow coefficient;(3)the establishment of the invariable form of strain-based,stress-based,or energy-based EPWP ratio formulas and the unique relationship between the new proxy of liquefaction resistance and the number of cycles required to reach liquefaction;(4)the establishment of the invariable form of the predictive formulas of small strain modulus and strain-dependent shear modulus;and(5)the investigation on the effects of stress-induced anisotropy on liquefaction susceptibility and dynamic deformation *** gained through the critical review of these advances in the past decades offer a perspective for future research to further resolve the fundamental issues concerning the liquefaction mechanism and responses of coral sandy sites subjecte

关键词： liquefaction susceptibility dynamic deformation characteristics coral sandy soil cyclic loading review and prospect

Development and experiments of low frequency ultrasonic electrostatic atomizing nozzle with double resonators

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International Journal of Agricultural and Biological Engineering 2022年第4期15卷 39-48页

作者： Jianmin Gao Ke Xu Rui He Xiangchao chen Mazhar Hussain Tunio School of Agricultural Engineering Jiangsu UniversityZhenjiang 212013China

Fine droplets with high adhesion can greatly improve the efficiency of atomization ***,the development of a spray nozzle that can produce fine fog droplets with high adhesion is of great significance for *** to piezoelectric ultrasonic atomizer,Hartmann resonator low-frequency ultrasonic electrostatic atomizer has the advantages of large atomization volume and constant liquid chemical structure,but the droplet size is ***-speed gas can generate low-frequency ultrasonic vibration sound waves in Hartmann *** frequency and intensity of sound waves determine the atomization performance of supersonic atomizer ***,very few research literatures can be found on how the structure and operating parameters of Hartmann resonator affect the atomization *** order to improve the atomization performance of ultrasonic atomizer,a two-stage Hartmann resonator low-frequency ultrasonic electrostatic atomizer was *** shrinkage-type Laval tube was designed by fluid mechanics theory,and the design results were verified by fluent *** virtual orthogonal test method was used to optimize the structure parameters of two-stage resonator and spray test was carried *** results showed that when the included angle between the two stage resonators was 80°,the diameter was 4.86 mm,the tube length ratio was 1.0 and the gas pressure was 0.5 MPa,the droplet size could reach 22.05μ***,compared with the traditional Hartmann cavity with 90°included angle,the droplet size was decreased by 63%.The annular electrode was used as the charging electrode,and comsol Multiphysics software was used to simulate and calculate the deformation and crushing process of electrostatic droplets and the influence of different voltage,surface tension and droplet diameter on the droplet deformation *** results showed that:(1)the optimum charge range of the electrode ring was within 20 mm of the axial distance along the ele

关键词： ultrasonic atomization Laval tube two-stage resonance tube electrostatic spray deformation rupture simulation analysis

The anti-inflammatory effects of exercise on autoimmune diseases:A 20-year systematic review

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Journal of Sport and Health Science 2024年第3期13卷 353-367,I0001页

作者： Beibei Luo Dao Xiang Xiaorong Ji Xuan chen Rui Li Shuxin Zhang Yujun Meng David c.Nieman Peijie chen School of Exercise and Health Shanghai University of SportShanghai 200438China Shanghai Key Laboratory of Human Performance Shanghai University of SportShanghai 200438China Department of Diving and Hyperbaric Medicine Naval Medical CenterShanghai 200433China National Key Laboratory of Immunity and Inflammation Naval Medical UniversityShanghai 200433China Human Performance Laboratory Appalachian State UniversityNorth Carolina Research CampusKannapolisNC 28081USA Research Institute for Doping control Shanghai University of SportShanghai 200438China

Background:The anti-inflammatory effect of exercise may be an underlying factor in improving several autoimmune *** aim of this systematic review was to examine the evidence on the role of exercise training in mitigating inflammation in adolescents and adults with autoimmune ***:PubMed,Web of Science,and Embase databases were systematically reviewed for related studies published between January 1,2003,and August 31,*** randomized and non-randomized controlled trials of exercise interventions with autoimmune disease study participants that evaluated inflammation-related biomarkers were *** quality of evidence was assessed using the Tool for the assEssment of Study qualiTy and reporting in EXercise scale and cochrane bias risk ***:A total of 14,565 records were *** screening the titles,abstracts,and full texts,87 were eligible for the systematic *** studies were conducted in 25 different countries and included a total of 2779 participants(patients with autoimmune disease,in exercise or control groups).Overall,the evidence suggests that inflammation-related markers such as c-reactive protein,interleukin 6,and tumor necrosis factor a were reduced by regular exercise *** exercise interventions combined with multiple exercise modes were associated with greater ***:Regular exercise training by patients with autoimmune disease exerts an anti-inflammatory *** systematic review provides support for the promotion and development of clinical exercise intervention programs for patients with autoimmune *** patients with autoimmune disease can safely adopt moderate exercise training protocols,but changes in inflammation biomarkers will be modest at *** exercise interventions are ineffective or even modestly but transiently pro-inflammatory.

关键词： Autoimmune diseases cytokines Inflammation Physical activity Training

Optical disassembly of cellular clusters by tunable ‘tug-of-war’ tweezers

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Light(Science & Applications) 2016年第1期5卷 444-450页

作者： Anna S Bezryadina Daryl c Preece Joseph c chen Zhigang chen Department of Physics and Astronomy San Francisco State UniversitySan FranciscoCA 94132USA School of Mathematics and Physics The University of QueenslandBrisbaneQLD 4072Australia Department of NanoEngineering University of CaliforniaSan DiegoLa JollaCA 92093USA Department of Biology San Francisco State UniversitySan FranciscoCA 94132USA The MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Applied Physical Institute and School of PhysicsNankai UniversityTianjin 300457China

Bacterial biofilms underlie many persistent infections,posing major hurdles in antibiotic *** we design and demonstrate‘tug-of-war’optical tweezers that can facilitate the assessment of cell–cell adhesion—a key contributing factor to biofilm development,thanks to the combined actions of optical scattering and gradient *** a customized optical landscape distinct from that of conventional tweezers,not only can such‘tug-of-war’tweezers stably trap and stretch a rod-shaped bacterium in the observing plane,but,more importantly,they can also impose a tunable lateral force that pulls apart cellular clusters without any tethering or mechanical *** a proof of principle,we examined a Sinorhizobium meliloti strain that forms robust biofilms and found that the strength of intercellular adhesion depends on the growth *** technique may herald new photonic tools for optical manipulation and biofilm study,as well as other biological applications.

关键词： bacterial adhesion biofilm optical forces optical manipulation tug-of-war optical tweezers

Enhancement of Sinter Densification of SrO-BaO-Nb_2O_5-SiO_2 Tungsten-Bronze Glass-ceramics by Doping with P_2O_5

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Journal of Materials Science & Technology 2013年第8期29卷 731-736页

作者： J.c.chen Y.Zhang Shenyang Research and Development centre for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences State Key Laboratory of New ceramics and Fine Processing Institute of Nuclear and New Energy TechnologyTsinghua University

Densification behaviors of SrO-BaO-Nb2O5-SiO2 based glass-ceramics prepared by conventional sintering were investigated with an emphasis on the influence of P2O5 content. Although P2O5 dopant did not modify the surface crystallization mechanism, it resulted in a decrease of the glass transition temperature, which facilitates the viscous glass flow necessary for sintering. However, premature crystallization of （Sr, Ba）Nb2O6 induced by addition of excess amount of P2O5 essentially retarded sintering due to the formation of closed pores in the matrix. The SrO-BaO-Nb2O5-SiO2 glass with 1.0 mol% P2O5 （SBN-1P） showed the best sinter densification, which was accomplished at about 850 ℃.

关键词： Sintering densification DieLectric properties Glass-ceramic

A refined representation method of the particle size distribution curve based on grading entropy

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Particuology 2024年第5期88卷 302-311页

作者： Xing Li Qun chen Zhaozhao Liu cheng Zhou chen Wang chen chen State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China

The particle size distribution(PSD)curve is an important expression of the basic properties of the *** characteristic parameters such as median particle size D_(50),effective particle size D_(10),and some combinations of characteristic parameters can only represent some points of the PSD curve,failing to represent all information of the PSD *** this paper,a fraction characteristic parameter F that could reflect the fraction size variation of the PSD curve was introduced based on grading *** a new presentation method of the A-B-F three parameters was proposed for a refined representation of the PSD *** was found that the newly constructed model not only better represents the differences in the width of PSD curves but also has a higher sensitivity than the A-B two-parameter model proposed by Lő*** PSD curves with similar distributions,the new presentation method has a higher degree of discrimination than that of the D_(50)-c_(u)-c_(c) three-parameter or the four-parameter combination G_(c) proposed by ***,the application of this new method in describing the spatial nonuniformity distribution of depositions and predicting the soil hydraulic conductivity was *** research results can provide a reference for the refined representation of PSD curves.

关键词： Grading entropy Particle size distribution curve Refined representation

Theoretical and experimental study of a bi-stable piezoelectric energy harvester under hybrid galloping and band-limited random excitations

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 461-478页

作者： Haitao LI Tianyu ZHENG Weiyang QIN Ruilan TIAN Hu DING J.c.JI Liqun chen Department of Engineering Mechanics North University of ChinaTaiyuan 030051China Department of Engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechnoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China School of Mechanical and Mechatronic Engineering University of Technology SydneyNew South Wales 2007Australia

In the practical environment,it is very common for the simultaneous occurrence of base excitation and *** the combined energy of vibration and wind with a single energy harvesting structure is *** this purpose,the effects of the wind speed and random excitation level are investigated with the stochastic averaging method(SAM)based on the energy *** results of the analytical prediction are verified with the Monte-carlo method(McM).The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester(BEH)realize the performance enhancement for a weak base ***,as the strength of the wind increases to a particular level,the influence of the random base excitation on the dynamic responses is weakened,and the system exhibits a periodic galloping response.A comparison between a BEH and a linear energy harvester(LEH)indicates that the BEH demonstrates inferior performance for high-speed *** experiments are conducted to investigate the validity of the theoretical prediction and numerical *** experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind ***,as the speed of the incoming wind is up to a particular level,the disadvantage of the BEH becomes clear and evident.

关键词： bi-stability inter-well response galloping band-limited random

Vitamin D for the prevention and treatment of pancreatic cancer

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World Journal of Gastroenterology 2009年第27期15卷 3349-3354页

作者： Kun-chun chiang Tai c chen Department of Surgery Chang Gung Memorial Hospital Chang Gung University Taoyuan 333Taiwan China Boston University School of Medicine 715 Albany Street Boston MA 02118 United States

Pancreatic cancer is ranked fi fth among cancer-related deaths worldwide with a 5-year survival rate of less than 5%. currently, surgery is the only effective therapy. However, most patients are diagnosed in the late stage and are not suitable for receiving curative surgery. Moreover, pancreatic cancer doesn't respond well to traditional chemotherapy and radiotherapy, leaving little effective treatment for advanced pancreatic cancer cases. 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], the biologically active form of vitamin D3, was originally identifi ed during studies of calcium and bone metabolism, though it is now recognized that it exerts biological effects in almost every tissue in the body. Abundant evidence has shown that 1α,25(OH)2D3 has antiproliferative, apoptotic, pro-differentiation and antiangiogensis effects in many types of cancer cells in vivo and in vitro, including breast, prostate, and colon. Similarly, the antitumor growth effect of 1α,25(OH)2D3 on pancreatic cells has been demonstrated. The clinical use of 1α,25(OH)2D3 is impeded by the lethal side effects of hypercalcemia and hypercalciuria. Therefore, 1α,25(OH)2D3 analogs, which are either equipotent or more potent than 1α,25(OH)2D3 in inhibiting tumor cell growth but with fewer hypercalcemic and hypercalciuric side effects, have been developed for the treatment of different cancers. Recently, a pre-clinical study demonstrated that a less calcemic analog of 1α,25(OH)2D3, 19-nor-1α,25(OH)2D2 (Paricalcitol), is effective in inhibiting tumor growth in vitro and in vivo , via upregulation of p21 and p27 tumor suppressor genes. Studies on the anti-tumor effects of a more potent analog of Paricalcitol are underway.1α,25(OH)2D3 and its analogs are potentially attractive novel therapies for pancreatic cancer.

关键词：维生素D 胰腺癌治疗预防