Insights into Nano-and Micro-Structured Scaffolds for Advanced Electrochemical Energy Storage

Adopting a nano-and micro-structuring approach to fully unleashing the genuine potential of electrode active material benefits in-depth understandings and research progress toward higher energy density electrochemical energy stor-age devices at all technology readiness levels.Due to various challenging issues,especially limited stability,nano-and micro-structured(NMS)electrodes undergo fast electrochemical performance degradation.The emerging NMS scaffold design is a pivotal aspect of many electrodes as it endows them with both robustness and electrochemical performance enhancement,even though it only occupies comple-mentary and facilitating components for the main mechanism.However,extensive efforts are urgently needed toward optimizing the stereoscopic geometrical design of NMS scaffolds to minimize the volume ratio and maximize their functionality to fulfill the ever-increasing dependency and desire for energy power source supplies.This review will aim at highlighting these NMS scaffold design strategies,summariz-ing their corresponding strengths and challenges,and thereby outlining the potential solutions to resolve these challenges,design principles,and key perspectives for future research in this field.Therefore,this review will be one of the earliest reviews from this viewpoint.

A gradient nano/micro-structured surface layer on copper induced by severe plasticity roller burnishing

In order to investigate a gradient nano/micro-structured surface layer on pure copper produced by severe plasticity roller burnishing （SPRB） and grain refinement mechanism, the microstructure characteristics and material properties of sample at various depths from the topmost surface were investigated by SEM, TEM, XRD, OM etc. The experimental results show that the gradient nano/micro-structure was introduced into the surface layer of over 100μm in thickness. The remarkable increase in hardness near the topmost surface was mainly attributed to the reduced grain size. The equiaxed nano-sized grains were in random orientation and the most of their boundaries were low-angle grain boundaries （LAGBs）. The coarse grains are refined into the few micro-sized grains by dislocation activities;deformation twinning was found to be the primary form for the formation of submicron grains;the formation of nanostructure was dominated by dislocation activities accompanied with rotation of grains in local region.

Simulation of GaN micro-structured neutron detectors for improving electrical properties

Nowadays,the superior detection performance of semiconductor neutron detectors is a challenging task.In this paper,we deal with a novel GaN micro-structured neutron detector(GaN-MSND)and compare three different methods such as the method of modulating the trench depth,the method of introducing dielectric layer and p-type inversion region to improve the width of depletion region(W).It is observed that the intensity of electric field can be modulated by scaling the trench depth.On the other hand,the electron blocking region is formed in the detector enveloped with a dielectric layer.Furthermore,the introducing of p-type inversion region produces new p/n junction,which not only promotes the further expansion of the depletion region but also reduces the intensity of electric field produced by main junction.It can be realized that all these methods can considerably enhance the working voltage as well as W.Of them,the improvement on W of GaN-MSND with the p-type inversion region is the most significant and the value of W could reach 12.8μm when the carrier concentration of p-type inversion region is 10^17 cm^-3.Consequently,the value of W is observed to improve 200%for the designed GaN-MSND as compared with that without additional design.This work ensures to the researchers and scientific community the fabrication of GaN-MSND having superior detection limit in the field of intense radiation.

Robustness and precision evaluation of the form error of micro-structured surfaces using real coded genetic algorithm

To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm （RCGA）. The meth- od employed the average squared distance as the matching criterion. The point to surface distance was achieved by use of iterative method and the modeling of RCGA for the surface matching was also presented in detail. Parameter selection for RCGA including the crossover rate and population size was discussed. Evaluation results of series simulated surfaces without form error show that this method can achieve the accuracy of root mean square deviation （ Sq ） less than 1 nm and surface pro- file error （ St ） less than 4 nm. Evaluation of the surfaces with different simulated errors illustrates that the proposed method can also robustly obtain the form error with nano-meter precision. The e- valuation of actual measured surfaces further indicates that the proposed method is capable of pre- cisely evaluating micro-structured surfaces.

Microstructural evolution and deformation mechanisms of superplastic aluminium alloys:A review

Aluminium alloy is one of the earliest and most widely used superplastic materials.The objective of this work is to review the scientific advances in superplastic Al alloys.Particularly,the emphasis is placed on the microstructural evolution and deformation mechanisms of Al alloys during superplastic deformation.The evolution of grain structure,texture,secondary phase,and cavities during superplastic flow in typical superplastic Al alloys is discussed in detail.The quantitative evaluation of different deformation mechanisms based on the focus ion beam(FIB)-assisted surface study provides new insights into the superplasticity of Al alloys.The main features,such as grain boundary sliding,intragranular dislocation slip,and diffusion creep can be observed intuitively and analyzed quantitatively.This study provides some reference for the research of superplastic deformation mechanism and the development of superplastic Al alloys.

Model of self-generated magnetic field generation from relativistic laser interaction with solid targets

Generation of self-generated annular magnetic fields at the rear side of a solid target driven by relativistic laser pulse is investigated by using theoretical analysis and particle-in-cell simulations.The spatial strength distribution of magnetic fields can be accurately predicted by calculating the net flow caused by the superposition of source flow and return flow of hot electrons.The theoretical model established shows good agreement with the simulation results,indicating that the magnetic-field strength scales positively to the temperature of hot electrons.This provides us a way to improve the magnetic-field generation by using a micro-structured plasma grating in front of the solid target.Compared with that for a common flat target,hot electrons can be effectively heated with the well-designed grating size,leading to a stronger magnetic field.The spatial distribution of magnetic fields can be modulated by optimizing the grating period and height as well as the incident angle of the laser pulse.

Characteristic and optimization of ferrite-rich sulfoaluminate-based composite cement suitable for cold region tunnels

To develop suitable grouting materials for water conveyance tunnels in cold regions,firstly,this study investigated the performance evolution of ferrite-rich sulfoaluminate-based composite cement(FSAC grouting material)at 20 and 3℃.The results show that low temperature only delays the strength development of FSAC grouting material within the first 3 d.Then,the effect of four typical early strength synergists on the early properties of FSAC grouting material was evaluated to optimize the early(£1 d)strength at 3℃.The most effective synergist,Ca(HCOO)_(2),which enhances the low-temperature early strength without compromising fluidity was selected based on strength and fluidity tests.Its micro-mechanism was analyzed by XRD,TG,and SEM methods.The results reveal that the most suitable dosage range is 0.3 wt%−0.5 wt%.Proper addition of Ca(HCOO)_(2)changed the crystal morphology of the hydration products,decreased the pore size and formed more compact hydration products by interlocking and overlapping.However,excessive addition of Ca(HCOO)_(2)inhibited the hydration reaction,resulting in a simple and loose structure of the hydration products.The research results have reference value for controlling surrounding rock deformation and preventing water and mud inrushes during the excavation in cold region tunnels.

模块式四芯光纤信道分束器及其性能测试方法

针对传统多芯光纤分束器与多芯光纤连接方式的不足,如拆卸困难和测试方案需额外引入测试分束器等问题,采用双包层光纤束拉锥法制备了四芯光纤信道分束器。为了方便器件的测试和连接,在单模光纤和四芯光纤的尾端分别制备了LC/PC型的活动连接器,从而形成了单个模块式的四芯光纤信道分束器;同时,提出了一种针对该模块式器件的镜像反射式测试方法。这种测试方法仅需要一个LC/PC活动连接器式反射器,就可以轻松完成器件的插入损耗和芯间串扰的测试。测试结果表明,所制备的四芯光纤信道分束器性能优异,其最大插入损耗和最大芯间串扰分别为0.84 dB和-46.32 dB。

Micro-structural evolution and their effects on physical properties in different types of tectonically deformed coals

The macromolecular structure of tectonically deformed coals(TDC)may be determined by the deformation mechanisms of coal.Alterations of the macromolecular structure change the pore structure of TDC and thereby impact physical properties such as porosity and permeability.This study focuses on structure and properties of TDC from the Huaibei and Huainan coal mining areas of southern North China.Relationships between the macromolecular structure and the pore structure of TDC were analyzed using techniques such as X-ray diffraction,high-resolution transmission electron microcopy,and the low-temperature nitrogen adsorption.The results indicated that the directional stress condition can cause the arrangement of basic structural units(BSU)more serious and closer.And,the orientation is stronger in ductile deformed coal than in brittle deformed coal.Tectonic deformation directly influences the macromolecular structure of coal and consequently results in dynamic metamorphism.Because the size of BSU in brittle deformed coal increases more slowly than in ductile deformed coal,frictional heating and stress-chemistry of shearing areas might play a more important role,locally altering coal structure under stress,in brittle deformed coal.Strain energy is more significant in increasing the ductile deformation of coal.Furthermore,mesopores account for larger percentage of the nano-scale pore volume in brittle deformed coals,while mesopores volume in ductile deformed coal diminishes rapidly along with an increase in the proportion of micropores and sub-micropores.This research also approved that the deformations of macromolecular structures change nano-scale pore structures,which are very important for gas adsorption and pervasion space for gas.Therefore,the exploration and development potential of coal bed methane is promising for reservoirs that are subjected to a certain degree of brittle deformation(such as schistose structure coal,mortar structure coal and cataclastic structure coal).It also holds promise for TDC resulting from wrinkle structure coal of low ductile deformation and later superimposed by brittle deformation.Other kinds of TDC suffering from strong brittle-ductile and ductile deformation,such as scale structure coal and mylonitic structure coal,are difficult problems to resolve.

EXPERIMENTAL STUDY ON MACRO AND MICRO-STRUCTURE OF METALLIC PARTS BUILT BY LOW-POWER LASER CLADDING

A low-power CO_2 laser is used to deposit Fe powder and mixture of Fe andcarbon powder on substrates respectively, and the macro and micro-structure of the formed samplesare investigated. It is demonstrated that most grains of these samples are equi-axed. This isderived from the high nucleation velocity in the shallow melt pool besides rapid solidification ofthe liquid-state alloy or metal. Bainitic structure, combination of pearlite and ferrite structureand ferrite structure are seen respectively in the samples involving various amounts of carbon owingto no martensitic transformation in these small samples.

Research on the process of fabricating a multi-layer metal micro-structure based on UV-LIGA overlay technology

In this paper,we report the study of the process of fabricating a multi-layermetal micro-structure using UV-LIGA overlay technology,includingmask fabrication,substrate treatment,and UV-LIGA overlay processes.To solve the process problems in the masking procedure,the swelling problemof the first layer of SU-8 thick photoresist was studied experimentally.The 5μmline-width compensation and closed 20μmand 30μmisolation strips were designed and fabricated around the micro-structure pattern.The pore problemin the Ni micro-electroforming layer was analyzed and the electroforming parameters were improved.The pH value of the electroforming solution should be controlled between 3.8 and 4.4 and the current density should be below 3 A/dm^2.To solve the problems of high inner stress and incomplete development of the micro-cylinder hole array with a diameter of 30μm,the lithography process was optimized.The pre-baking temperature was increased via gradient heating and rose every 5℃ from 65℃ to 85℃ and then remained at 85℃ for 50 min–1 h.In addition,the full contact exposure was used.Finally,a multi-layer metal micro-structure with high precision and good quality of microelectroforming layer was fabricated using UV-LIGA overlay technology.

The effect of agglomerate on micro-structural evolution in solid-state sintering

Discrete element method （DEM） is used in the present paper to simulate the microstructural evolution of a planar layer of copper particles during sintering. Formation of agglomerates and the effect of their rearrangement on densification are mainly focused on. Comparing to the existing experimental observations, we find that agglomerate can form spontaneously in sintering and its rearrangement could accelerate the densification of compacts. Snapshots of numerical simulations agree qualitatively well with experimental observations. The method could be readily extended to investigate the effect of agglomerate on sintering in a three- dimensional model, which should be very useful for understanding the evolution of microstructure of sintering systems.

Effect of particle micro-structure on the electrochemical properties of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode material

Ni-rich layered material is a kind of high-capacity cathode to meet the requirement of electric vehicles.As for the typical LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) material,the particle formation is significant for electrochemical properties of the cathode.In this work,the structure,morphology,and electrochemical performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) secondary particles and single crystals were systematically studied.A lower Ni^(2+)/Ni^(3+)molar ratio of 0.66 and a lower residual alkali content of 0.228wt%were achieved on the surface of the single crystals.In addition,the single crystals showed a discharge capacity of 191.6 mAh/g at 0.2 C(~12 mAh/g lower than that of the secondary particles)and enhanced the electrochemical stability,especially when cycled at 50℃ and in a wider electrochemical window(between 3.0 and 4.4 V vs.Li+/Li).The LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) secondary particles were suitable for applications requiring high specific capacity,whereas single crystals exhibited better stability,indicating that they are more suitable for use in long life requested devices.

Synthesis of Mg_5(CO_3)_4(OH)_2·4H_2O with Flower-like Micro-structure and Its Catalytic Activity for Transesterification of Dimethyl Carbonate with Phenol

A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 （CO3 ）4 （OH）2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 （CO3）4 （OH）2·4H2O were characterized by means of X-ray diffractometry （XRD）, fieldemission scanning electron microscopy（FE-SEM）. Brunauer-Emmett-Teller（BET） surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 （CO3）4（ OH）2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol.

NUMERICAL SIMULATION FOR CONVECTION-DIFFUSION PROBLEM WITH PERIODIC MICRO-STRUCTURE

In this article, the convection dominated convection-diffusion problems with the periodic micro-structure are discussed. A two-scale finite element scheme based on the homogenization technique for this kind of problems is provided. The error estimates between the exact solution and the approximation solution, of the homogenized equation or the two-scale finite element scheme are analyzed. It is shown that the scheme provided in this article is convergent for any fixed diffusion coefficient 5, and it may be convergent independent of δ under some conditions. The numerical results demonstrating the theoretical results are presented in this article.

Temperature Induces Self-assembly of Silicon Nano/Micro-structure based on Multi-physics Approach

A three-dimensional dynamic model for nano/micro-fabrications of silicon was presented. With the developed model, the fabrication process of silicon on nothing（SON） structure was quantitatively investigated. We employ a diffuse interface model that incorporates the mechanism of surface diffusion. The mechanism of the fabrication is systematically integrated for high reliability of computational analysis. A semi-implicit Fourier spectral scheme is applied for high efficiency and numerical stability. Moreover, the theoretical analysis provides the guidance that is ordered by the fundamental geometrical design parameters to guide different fabrications of SON structures. The performed simulations suggest a substantial potential of the presented model for a reliable design technology of nano/micro-fabrications.

On a Standard Parametric Modeling Method of Micro-Structure of Plain Woven Composite

A new standard parametric modeling method of the micro-structure of plain woven composite is proposed. It is based on good analysis of the mechanical property of the yarn, weaving law of plain woven, and other factors. The method implements a woven fabric composite visual engineering modeling process standardization, and it gives five steps to calculate the key micro-structural parameters of the yarn including the cross-section and the trajectory of the central Line. On the basis, the digital model of a plain woven composite has been constructed. The experimental result shows that the forecast for the mechanical property of the model using finite-element simulation analysis is consistent with the actual value. The shape and the structure of the model are also consistent with the solid.

The Effect of Micro-Structure on Fatigue Behaviour of Intact Sandstone

With advent of servo-controlled stiff testing machines, it is now possible to conduct tests on a rock in the laboratory under different variable controlled conditions. In this paper, cyclic fatigue behaviour of intact sandstone obtained from the rock burst prone coal mine in the Czech Republic were presented. Tests were conducted on MTS- 816 rock test system in the laboratory on intact rock samples of L/D ratio 2 under cyclic loading frequency of 0.1, 1, 3, 5, 7 and 10 Hz at amplitude of 0.1 mm under displacement control mode until failure of the samples in uni-axial compression. From, the primary results it was observed that at low loading frequency range of 0.1 to 3 Hz, there was degradation of the rock samples in terms of fatigue strength and modulus. While, at higher frequency rose-up in strength and deformation properties were observed. It was observed that the machine behaviour in terms of amplitude at higher loading frequencies might be affecting the results. It seemed that machine behaviour of servo-hydraulic testing system was also dependent on rock type under investigation.

施工缝加固后铁路重力式桥墩的抗震性能试验研究

为研究施工缝加固后铁路重力式桥墩的抗震性能,选用玄武岩纤维布加固墩身施工缝,采用拟静力试验研究施工缝加固前后桥墩的抗震性能,从加固前后桥墩的破坏特征,滞回曲线和骨架曲线,以及承载力、累积耗能、刚度等指标对桥墩进行抗震性能分析。试验结果表明:采用玄武岩纤维布加固墩身施工缝后,桥墩的破坏面出现在墩底,施工缝区域未发生破坏;与未加固的桥墩相比,施工缝加固后的桥墩的极限承载力、耗能能力和刚度都得到了提升。

光纤溶脂收紧松弛皮肤联合脂肪填充对治疗面部老化患者满意度评分、面部老化改善的影响

目的分析光纤溶脂收紧松弛皮肤联合脂肪填充对治疗面部老化患者满意度评分、面部老化改善的影响。方法选取2022年5月至2023年5月期间我院接受整形治疗的100例面部老化患者,按照治疗方法将其分为2组,每组均为50例,对照组采取光纤溶脂收紧松弛皮肤治疗,观察组采取光纤溶脂收紧松弛皮肤联合脂肪填充治疗,对比两组改善效果。结果两组患者不良反应发生率无明显差异(P>0.05),观察组优良率、整形后生活质量评分、手术满意度高于对照组(P<0.05)。结论面部老化患者采取光纤溶脂收紧松弛皮肤联合脂肪填充治疗,可以有效改善患者面部老化,且效果良好,患者满意度更高,且可以让患者在整形后获得更高的生活质量,值得广泛推广及应用。