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Two 8-node quadrilateral spline elements by B-net method

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Acta Mechanica sinica 2012年第6期28卷 1620-1629页

作者： juan Chen chong-jun Li school of Mathematics and Quantitative Economics Dongbei University of Finance and Economics school of Mathematical sciences Dalian University of Technology

Isoparametric quadrilateral elements are widely used in the finite element method, but the accuracy of the isoparametric quadrilateral elements will drop obviously deteriorate due to mesh distortions. spline functions have some properties of simplicity and conformality. Two 8-node quadrilateral elements have been developed using the trian- gular area coordinates and the B-net method, which can ex- actly model the quadratic field for both convex and concave quadrangles. some appropriate examples are employed to evaluate the performance of the proposed elements. The nu- merical results show that the two spline elements can obtain solutions which are highly accurate and insensitive to mesh distortions.

关键词： spline finite element B-net method Quadri-lateral element - Bivariate spline interpolation The secondorder completeness

Development of quadrilateral spline thin plate elements using the B-net method

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Acta Mechanica sinica 2013年第4期29卷 567-574页

作者： juan Chen chong-jun Li school of Mathematics and Quantitative Economics Dongbei University of Finance and Economics school of Mathematical sciences Dalian University of Technology

The quadrilateral discrete Kirchhoff thin plate bending element DKQ is based on the isoparametric element Q8, however, the accuracy of the isoparametric quadrilateral elements will drop significantly due to mesh distortions. In a previous work, we constructed an 8-node quadrilateral spline element L8 using the triangular area coordinates and the B- net method, which can be insensitive to mesh distortions and possess the second order completeness in the Cartesian co- ordinates. In this paper, a thin plate spline element is devel- oped based on the spline element L8 and the refined tech- nique. Numerical examples show that the present element indeed possesses higher accuracy than the DKQ element for distorted meshes.

关键词： spline finite element ~ Refined quadrilateral el-ement ~ Discrete Kirchhoff plate element ~ Triangular areacoordinates ~ B-net method

Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

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Neural Regeneration Research 2025年第2期20卷 394-401页

作者： josep Tomàs Víctor Cilleros-Mañé Laia just-Borràs Marta Balanyà-segura Aleksandra Polishchuk Laura Nadal Marta Tomàs Carolina silvera-simón Manel M.santafé Maria A.Lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorB

Escape and stand of the Pluto Atmosphere

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Communications in Theoretical Physics 2002年第7期38卷 125-127页

作者： GAO chong-Yi school of Physical science and Technology Lanzhou University Lanzhou 730000 China

Molar mass μmin of the lightest gas, which will exist "forever" in the atmosphere at the planet surface,can be evaluated by jeans rule. The μmin of Pluto is 17.3 g@ mol-1. It is evident that both N2 and CO can be major atmospheric composition at the Pluto surface, and will exist "forever". CH4 can only be escaping slowly from Pluto atmosphere, and still holds quite a proportion in current Pluto atmosphere. However, it will not escape from Titan (or jupiter, saturn) atmosphere largely, and will exist "forever". Given the quantitylevelof partial pressure of CH4 in Pluto and Titan (or jupiter, saturn) original atmosphere is the same, it will be clear that the current partial pressure of CH4 in Pluto surface atmosphere is 10-3 Pa.

关键词： planet atmosphere, Pluto atmosphere, jeans rule, atmospheric composition, escape

Bioleaching and biosorption behavior of vanadium-bearing stone coal by Bacillus mucilaginosus

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International journal of Minerals,Metallurgy and Materials 2023年第2期30卷 283-292页

作者： Yingbo Dong shijia chong Hai Lin school of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants Beijing 100083China

The recovery of vanadium(V)from stone coal by bioleaching is a promising *** bioleaching experiments and the biosorption experiments were carried out,aiming to explore the adsorption characteristics of Bacillus mucilaginosus(***)on the surface of vanadium-bearing stone coal,and the related mechanisms have been *** bioleaching at 30℃ for 28 d,the cumulative leaching rate of V reached 60.2%.The biosorption of *** on stone coal was affected by many *** the pH value of leaching system is 5.0,strong electrostatic attraction between bacteria and stone coal promoted *** in the logarithmic growth phase had mature and excellent biosorption *** initial bacterial concentration of 3.5×10^(8) CFU/mL was conducive to adhesion,with 38.9%adsorption rate and 3.6×10^(7) CFU/g adsorption *** adsorption of *** on the stone coal conformed to the Freundlich model and the pseudo-second-order kinetic *** surface carried functional groups(-CH_(2),-CH_(3),-NH_(2),etc.),which were highly correlated with the adsorption *** addition,biosorption changed the surface properties of stone coal,resulting in the isoelectric point(IEP)approaching the *** results could provide an effective reference for the adsorption laws of bacteria on minerals.

关键词： Bacillus mucilaginosus vanadium-bearing stone coal bioleaching biosorption

Toward tunable shape memory effect of NiTi alloy by grain size engineering:A phase field study

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journal of Materials science & Technology 2024年第1期168卷 276-289页

作者： Bo Xu chong Wang Qingyuan Wang Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan ProvinceSichuan UniversityChengdu 610065China Department of Mechanical science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Key Laboratory of Deep Underground science and Engineering (Sichuan University)Ministry of EducationChengdu 610065China

The inelastic deformations of shape memory alloys(sMAs)always show poor controllability due to the avalanche-like martensite transformation,and the effective control for the deformation of precision de-vices has been not yet *** this work,the phase field method was used to investigate the shape memory effects(sMEs)of NiTi sMAs undergoing grain size(Gs)engineering,to obtain tunable one-way and stress-assisted two-way sMEs(OWsME and sATWsME).The OWsME and sATWsME of the systems with various gradient-nanograin structures and bimodal grain structure,as well as that with geometric gradients were *** simulated results indicate that due to the Gs dependences of martensite transformation and reorientation,the occurrence and expansion of martensite reorientation,martensite transformation and its reverse can be efficaciously controlled via the Gs *** combining the Gs engineering and geometric gradient design,since the effects of Gs and stress gradient can be su-perimposed or competing,and the responses of martensite reorientation,martensite transformation and its reverse to this are different,the OWsME and sATWsME of the geometrically graded systems with various nanograin structures can exhibit different improvements in *** short,the reorienta-tion hardening modulus during OWsME is increased and the transformation temperature window during sATWsME is widened by Gs engineering,indicating the improved controllability of *** optimal Gs engineering schemes revealed in this work provide the basic reference and guidance for designing tun-able sMEs and producing NiTi-based driving devices catering to desired functional performance in various engineering fields.

关键词： Phase field NiTi shape memory effect Grain size engineering Geometric gradient

True polar wander in the Earth system

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science China Earth sciences 2023年第6期66卷 1165-1184页

作者： chong WANG Ross N.MITCHELL state Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China

True polar wander(TPW),or planetary reorientation,is the rotation of solid Earth(crust and mantle)about the liquid outer core in order to stabilize Earth’s rotation due to mass *** TPW is well-documented on Earth presently with satellites and for multiple planets and moons in the solar system,the prevalence of TPW in Earth history remains *** a history of controversy,both the physical plausibility of TPW on Earth and an empirical basis for it are now *** resistance to the old idea likely stems from the fact that,like plate tectonics,TPW may influence much of the Earth system,thus acknowledging its existence requires rethinking how many different datasets are *** review summarizes the development of TPW as a concept and provides a framework for future research that no longer regards TPW like a ghost process that may or may not exist,but as an integral part of the Earth system that can relate shallow and deep processes that are otherwise only mysteriously ***,we focus on the temporal regularity of large TPW,and discuss its relationship with the supercontinent-megacontinent cycle based on previous *** suggest the assembly of megacontinents has a close linkage to large ***,supercontinent tenure and breakup have a close linkage to fast *** effects of TPW on sea level changes,paleoclimate,biological diversity,and other facets of the Earth system are presented and require interdisciplinary tests in the future.

关键词： True polar wander(TPW) Planetary reorientation Apparent polar wander(APW) Mantle convection supercontinent cycle Megacontinent

Lesson Learned from COVID-19 Retrospective study: An Entropy-Based Clinical-Interpretable scorecard for Mortality Risk Control at ICU Admission

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Tsinghua science and Technology 2024年第1期29卷 34-45页

作者： chong Yao chonghui Huangqi Anpeng Huang Laboratory of Network Information security Beihang UniversityBeijing 100191China Andrew and Erna Viterbi school of Engineering University of Southern CaliforniaLos AnglesCA 90089USA Beijing Goodwill Information and Technology Co. Ltd.and Mobile Health LaboratoryPeking UniversityBeijing 100871China

With severe acute respiratory syndrome coronavirus 2 spreading globally and causing 2019 coronavirus disease(COVID-19),a challenge that we unprepared for was about how to optimally plan and distribute limited top-medical resources for patients in need of urgent *** address this challenge,physicians desperately needed a scientific tool to methodically differentiate between cases with varying *** this study,the unique data of COVID-19 intensive care unit(ICU)patients provided by the national medical team in Wuhan were classified into discrete and continuous variable *** continuous data were discretized using an entropy-based method and transformed into serial information margins,in which each information margin is related to a specific symptom or clinical ***,all these native and processed discrete data were used to configure a readable scorecard through logistic regression,which is the desired scientific tool aforementioned.A total of 322 ICU patients(age:[median:64,interquartile range:54-75],males:178[55.28%],and death:72[22.36%])were included in the *** of mortality in COVID-19 patients can be evaluated using a scorecard model(calibration slope:1.343,Brier:0.048,Dxy=0.972,and population stability index=0.071),with desired model performances(accuracy=0.948,area under curve=0.99,sensitivity=1,and specificity=0.939).This new model can interpret clinical meanings from complex data,and compare it with existing machine learning methods through a black-box *** new data-information model answers a critical question of how a computing algorithm produces clinically meaningful results that will help physicians logically allocate medical resources for COVID-19 ***,this tool has limitations,giving that this research is a retrospective ***,this tool will be tested further and optimized for adaptation to similar clinical cases in the future.

关键词： COVID-19 scorecard clinical-interpretable machine learning ICU admission control

Neural adaptive control for a ground experiment of the space proximity operation in a six-degree-of freedom micro-gravity simulation system

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Chinese journal of Aeronautics 2020年第9期33卷 2420-2433页

作者： chong sUN jianping YUAN Zhanxia ZHU school of Astronautics Northwestern Polytechnical UniversityXi'an 710100China Research and Development Institute of Northwestern Polytechnical University in shenZhen Shenzhen518057China

In this study,a neural adaptive controller is developed for a ground experiment with a spacecraft proximity *** the water resistance in the experiment is highly nonlinear and can significantly affect the fidelity of the ground experiment,the water resistance must be estimated accurately and compensated using an active force *** this problem,a novel control algorithm combined with Chebyshev Neural Networks(CNN)and an Active Disturbance Rejection Control(ADRC)is ***,the CNN algorithm is used to estimate the water *** advantage of the CNN estimation is that the coefficients of the approximation can be adaptively changed to minimize the estimation *** with the ADRC algorithm,the total disturbance is compensated in the experiment to improve the *** dynamic model of the spacecraft proximity maneuver in the experiment is *** ground experiment of the proximity maneuver that considers an obstacle is provided to verify the efficiency of the proposed *** results demonstrate that the proposed method outperforms the pure ADRC method and can achieve close-to-real-time performance for the spacecraft proximity maneuver.

关键词： Active disturbance rejection control Adaptive controller Ground experiment Micro-gravity Obstacle avoidance spacecraft proximity