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Revealing and predicting the long-term biomechanical response of orthokeratology by developing a patient-specific computational model

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Science China(Physics,mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 156-168页

作者： Yifeng Li Zhuoran Yang Ziming Yan Huibin Shi Zhanli Liu Kaijie Wang Department of Engineering mechanics School of Aerospace Engineering Tsinghua University Beijing Tongren Eye center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology & Visual Sciences Key Lab

Orthokeratology(OK) is widely used for effective myopia correction and control. However, the incomplete understanding of its biomechanical mechanisms makes OK lens fitting rely heavily on clinician judgment, complicating accurate predictions of treatment outcomes. In this paper, we performed clinical experiments and numerical analysis to study corneal deformation modes and long-term changes in central corneal thickness. Clinical experiments were conducted on 194 Chinese myopic patients under OK treatment for 3 months. Based on the experimental data, a patient-specific computational biomechanical model for OK was established and validated. Specifically, the anisotropic mechanical properties of the cornea were incorporated into the model to describe the significant difference between its shear modulus(29.5 kPa) and tensile modulus(768.4 kPa). Additionally, a viscohyperelastic material model with a prolonged corneal relaxation time of 5.6 h was developed to capture the long-term deformation response. The results show that corneal thickness reduction in OK is primarily due to out-of-plane shear deformation,influenced by the cornea's low shear resistance. Modeling the extended corneal relaxation time is crucial for predicting long-term biomechanical responses. The computational model effectively captures long-term changes in central corneal thickness, potentially improving OK lens fitting accuracy.

关键词： orthokeratology computational biomechanical model long-term viscoelasticity myopia correction

Rapid and scalable preparation of highly quaternized polymer networks to achieve efficient simultaneous adsorption of iodide and pertechnetate

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Science China Chemistry 2025年第01期 337-349页

作者： Meiyun xu Song Gu Fulong Chen Zhe Zhao Peng Liu Daoben Hua State Key Laboratory of Radiation Medicine and Protection School of Radiological and Interdisciplinary Sciences (RAD-X) Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions Soochow University

The efficient separation of fission products,such as TcO4-and I-,holds strategic significance for the management of radioactive wastes and environmental *** this study,we propose an ultrafast strategy for scalable preparation of a highly quaternized organic network to facilitate efficient and synchronous separation of iodide and *** network can be prepared within a few minutes at room temperature,using polyethylenimine and 1,2,4,5-tetrakis（bromomethyl）benzene as building *** chlorine replacement,the network,abundantly decorated with quaternary ammonium groups （Cl@QPN）,exhibits an ultrahigh positive charge density of 7.6 mmol/*** enables the rapid and efficient enrichment of target anions through strong electrostatic Coulomb *** a result,Cl@QPN exhibits significantly higher adsorption rate constants of 0.830 g/（mg min） for ReO4-（a nonradioactive surrogate of TcO4-） and 0.677 g/（mg min） for I-compared to other ***,it possesses high adsorption capacities,reaching 1,681 mg/g for ReO4-and 917.4 mg/g for I-.Cl@QPN also demonstrates good selectivity towards target ions and shows efficient adsorption for99TcO4-.Additionally,Cl@QPN exhibits high dynamic processing capacities,handling up to 3,100 and 7,400 kg of simulated streams per kilogram of material for I-and ReO4-,respectively.

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Mechanical Properties and Deformation Mechanisms of Metallic Glasses Under Hydrostatic Pressure

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Acta Mechanica Solida Sinica 2023年第3期36卷 390-404页

作者： Haiming Lu Yao Tang Fanheng Jiang Panpan Wan Haofei Zhou center for x-mechanics Department of Engineering MechanicsZhejiang UniversityHangzhou 310027China

Metallic glasses(MGs)are promising structural materials with high strength,large elastic strain limit and enhanced wear *** the way to tune the mechanical performance of MGs,numerous efforts have been devoted to investigating the effect of hydrostatic pressure(σh)on the mechanical properties and deformation mechanisms of *** application of sufficiently large magnitudes ofσh to MGs has been considered a feasible way to improve strength and delocalize plastic deformation in *** this paper,we review recent studies on pressure-dependent thermodynamic properties,mechanical strength and hardness,as well as elevated ductility of MGs due to the pressure-induced change of deformation and failure *** of intriguing mechanical behaviors of MGs,and the corresponding theoretical modeling and atomistic understanding of plastic deformation in MGs under pure hydrostatic pressure and more general stress states are *** findings not only deepen the understanding of pressure-dependent mechanical behaviors of MGs,but also point out the potential of tuning mechanical behaviors of MGs through stress engineering.

关键词： Metallic glass Hydrostatic pressure Mechanical property Deformation mechanism Microstructure

A chemo-mechanical model for fully-coupled lithiation reaction and stress generation in viscoplastic lithiated silicon

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Science China(Technological Sciences) 2019年第8期62卷 1365-1374页

作者： BUREBI Yi Ming JIA Zheng QU Shaoxing Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Center for X-MechanicsDepartment of Engineering MechanicsZhejiang University

Development of stresses in silicon(Si) anodes of lithium-ion batteries is strongly affected by its mechanical properties. Recent experiments reveal that the mechanical behavior of lithiated silicon is viscoplastic, thereby indicating that lithiation-induced mechanical stresses are dependent on the lithiation reaction rate. Experimental evidence also accumulates that the rate of lithiation reaction is conversely affected by the magnitude of mechanical stresses. These experimental observations demonstrate that lithiation reaction and stress generation in silicon anodes are fully coupled. In this work, we formulate a chemo-mechanical model considering the two-way coupling between lithiation reaction and viscoplastic deformation in silicon nanoparticle *** on the model, the position of the lithiation interface, the interface velocity, and the lithiation-induced stresses can be solved simultaneously via numerical methods. The predicted interface velocity is in line with experimental measurements reported in the literature. We demonstrate that the lithiation-induced stress field depends on the lithiation reaction through two parameters:the migration velocity and the position of the lithiation interface. We identify a stress-mitigation mechanism in viscoplastic silicon anodes: the stress-regulated lithiation reaction at the interface serves as a "brake" to reduce the interface velocity and mitigate the lithiation-induced stresses, protecting the Si nanoparticle anode from being subjected to excessive mechanical stresses.

关键词： lithium-ion battery lithiation-induced stress stress-regulated lithiation viscoplasticity

A compact design of four-degree-of-freedom transmission electron microscope holder for quasi-four-dimensional characterization

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Science China(Technological Sciences) 2020年第7期63卷 1272-1279页

作者： ZHANG YiZhi BU YeQiang FANG xiaoYang WANG HongTao center for x-mechanics Zhejiang UniversityHangzhou 310027China Institute of Applied mechanics Zhejiang UniversityHangzhou 310027China

Electron tomography(ET) has been demonstrated to be a powerful tool in addressing challenging problems, such as understanding 3 D interactions among various microstructures. Advancing ET to broader applications requires novel instrumentation design to break the bottlenecks both in theory and in practice. In this work, we built a compact four-degree-of-freedom(threedirectional positionings plus self-rotation) nano-manipulator dedicated to ET applications, which is called x-Nano transmission electron microscope(TEM) holder. All the movements of the four degrees of freedom are precisely driven by built-in piezoelectric actuators, minimizing the artefacts due to vibration and drifting of the TEM stage. Full 360° rotation is realized with an accuracy of 0.05° in the whole range, which solves the missing wedge problem. Meanwhile, the specimen can move to the rotation axis with an integrated 3D nano-manipulator, greatly reducing the effort in tracking sample locations during ***, in-situ stimulation function can be seamlessly integrated into the x-Nano TEM holder so that dynamic information can be uncovered. We expect that more delicate researches, such as those about 3D microstructural evolution, can be carried out extensively by means of this holder in the near future.

关键词： electron tomography in-situ transmission electron microscopy nano manipulation

x-mechanics——An endless frontier

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Science China(Physics,mechanics & Astronomy) 2019年第1期62卷 1-8页

作者： Wei Yang HongTao Wang TieFeng Li Shaoxing Qu center for x-mechanics Zhejiang University Institute of Applied mechanics Zhejiang University Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University

In contrast to the conventional wisdom that mechanics is a relatively mature subject, the new manifestation of mechanics in an extended or crossed form is unfolding. mechanics is now powering all subjects, from physical sciences, life sciences to social sciences. We name this new phase for the development of mechanics x-mechanics. The present article outlines the contents of x-mechanics from four aspects: cross media, cross scales, cross compliances, and cross cyber/physical spaces. x-mechanics constitutes an endless frontier of science and technology.

关键词： x-mechanics soft matters multi-scales multi-physics adaptive

Cortical hem signaling center: functions, development, and potential implications for evolution and brain disorders

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Neural Regeneration Research 2025年第4期20卷 1079-1080页

作者： Victor V.Chizhikov Igor Y.Iskusnykh Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in *** cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).

关键词： epithelium Figure center

ANALYTICAL EVALUATION OF PERMANENT DEFLECTION OF A THIN CIRCULAR PLATE STRUCK NORMALLY AT ITS center BY A PROJECTILE

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Acta Mechanica Solida Sinica 2007年第2期20卷 117-122页

作者： Chen Liebin Yang Jialing Solid mechanics Research center Beijing University of Aeronautics and Astronautics Beijing 100083 China

The permanent deflection of a thin circular plate struck normally at its center by a projectile is studied by an approximate theoretical analysis, FEM simulation and experiment. The plate made of rate sensitive and strain-hardening material undergoes serious local deformation but is not perforated during the impact. The theoretical analysis is based on an energy approach, in which the Cowper-Symonds equation is used for the consideration of strain rate sensitive effects and the parameters involved are determined with the aid of experimental data. The maximum permanent deflections predicted by the theoretical model are compared with those of FEM simulation and published papers obtained both by theory and experiment, and good agreement is achieved for a wide range of thickness of the plates and initial impact velocities.

关键词： thin circular plate finite deflection impact strain rate sensitive strain-hardening

Lithiation-enhanced charge transfer and sliding strength at the silicon-graphene interface:A first-principles study

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Acta Mechanica Solida Sinica 2017年第3期30卷 254-262页

作者： Cheng Chang xiaoyan Li Zhiping xu Huajian Gao Applied mechanics Laboratory Department of Engineering Mechanics Center for Nano and Micro MechanicsCenter for Advanced Mechanics and Materials Tsinghua University School of Engineering Brown University

The application of silicon as ultrahigh capacity electrodes in lithiumion batteries has been limited by a number of mechanical degradation mechanisms including fracture, delamination and plastic ratcheting, as a result of its large volumetric change during lithiation and delithiation. Graphene coating is one feasible technique to mitigate the mechanical degradation of Si anode and improve its conductivity. In this paper, first-principles calculations are performed to study the atomic structure, charge transfer and sliding strength of the interface between lithiated silicon and graphene. Our results show that Li atoms segre- gate at the （lithiated） Si-graphene interface preferentially, donating electrons to graphene and enhancing the interfacial sliding resistance. Moreover, the interfacial cohesion and sliding strength can be further enhanced by introducing single-vacancy defects into graphene. These findings provide insights that can guide the design of stable and efficient anodes of silicon/graphene hybrids for energy storage applications.

关键词： Lithium-ion batteries Silicon anode Graphene coating Interracial sliding strength First-principles calculations