摘要：Based on the nonlocal strain gradient theory(NSGT),the static bending behaviors of an axially functionally graded(AFG)Bernoulli-Euler microbeam subjected to concentrated and distributed loads are *** material property of the AFG microbeam changes continuously along the longitudinal *** the basis of the minimum potential energy principle,the equations of motion and associated classical and non-classical boundary conditions are ***,Galerkin’s weighted residual method in conjunction with the normalization technique are utilized to solve the governing differential *** transverse deformations of the AFG microbeam suffering the sinusoidal distributed load within the framework of NSGT,nonlocal elasticity theory(NET),strain gradient theory(SGT)and classical elasticity theory(CET)are *** is observed that the bending flexibility of the microbeam decreases with the increase in the ratio of the material length scale parameter to the beam ***,the bending flexibility increases with the increase in the material nonlocal *** functionally graded parameter plays an important role in controlling the transverse *** study provides a theoretical basis and a technical reference for the design and analysis of AFG micro-beams in the related regions.

摘要：Due to their capability of reversibly accepting multi lithium ions,polyoxometalates(POMs)have been widely regarded as promising candidates for electrochemical lithium ***,the insulating nature of POMs hinders fast migration kinetics of lithium within the bulk of these ***,we propose the introduction of a local electric field surrounding the POM nanoparticles consisting of Mn and V where the concomitant Coulomb forces can accelerate the migration of lithium *** rationally hybridizing POMs with MXene nanosheets,the imbalanced charge distribution emerging at their interface produces the local electric field,thereby leading to a 250-fold increase of lithium diffusion *** this regard,a capacitive contribution as high as 81.7%at 1.0 mV sis ***,the POM nanoparticles could densely assemble on the surface of MXene nanosheets,offering highly packed electrodes and thus high volumetric *** to the improved lithiumion transfer kinetics,the POMs/MXenes composites are paired with activated carbon to produce lithium-ion capacitors which could offer a high energy density of 195.5 W h kgand a large power capability of 3800 W *** findings in this work could build a clear relationship between materials with different conductivities for designing electrode materials.

摘要：This paper focuses on the thermo-mechanical behaviors of functionally graded(FG)shape memory alloy(SMA)composite beams based on Timoshenko beam *** volume fraction of SMA fiber is graded in the thickness of beam according to a power-law function and the equivalent parameters are *** governing differential equations,which can be solved by direct integration,are established by employing the composite laminated plate *** influences of FG parameter,ambient temperature and SMA fiber laying angle on the thermo-mechanical behaviors are numerically simulated and discussed under different boundary *** indicate that the neutral plane does not coincide with the middle plane of the composite beam and the distribution of martensite is asymmetric along the *** the increments of the functionally graded parameter and ambient temperature make the composite beam become ***,the influence of the SMA fiber laying angle can be *** work can provide the theoretical basis for the design and application of FG SMA structures.

摘要：研究目的:提出一种新的腐蚀疲劳损伤演化模型,建立基于损伤演化的腐蚀疲劳寿命预测模型。创新要点:将应力腐蚀损伤与疲劳损伤非线性耦合,建立腐蚀疲劳损伤演化律,依托实验确定腐蚀疲劳损伤演化参数,形成基于损伤演化律的腐蚀疲劳寿命预测模型。研究方法:采用理论研究与实验验证相结合的研究方法。选取特定材料设计应力腐蚀实验,回归应力腐蚀门槛值应力和损伤参数(图2);查阅疲劳实验数据建立变幅疲劳损伤模型,将应力腐蚀损伤与变幅疲劳损伤非线性累加形成腐蚀疲劳损伤非线性演化模型。根据腐蚀疲劳实验结果,验证腐蚀疲劳损伤演化模型并确定非线性损伤累加参数(图5和6),形成基于损伤演化律的腐蚀疲劳寿命预测模型。重要结论:从损伤力学角度,将材料的腐蚀疲劳损伤处理成应力腐蚀损伤与疲劳损伤的非线性累加,形成腐蚀疲劳损伤演化模型。结合LY12CZ铝合金的试验结果,验证了损伤演化模型的可行性。该方法可以为材料腐蚀疲劳的寿命评价研究提供新的思路。

摘要：A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation *** relationship between the anions of the ILs and the catalytic activities was investigated,and the readily‐prepared IL tetraethylammonium imidazolate(TEAI)was found to exhibit the highest catalytic *** optimizing the reaction conditions,a PIC with a weight‐average molecular weight(Mw)of25600g/mol was obtained,in conjunction with an isosorbide conversion of92%.As a means of modifying the molecular flexibility and thermal properties of the PIC,poly(aliphatic diol‐co‐isosorbide carbonate)s(PAIC)s were successfully synthesized,again using TEAI,and polymers with Mw values ranging from29000to112000g/mol were obtained.13C NMR analyses determined that the PAIC specimens had random microstructures,while differential scanning calorimetry demonstrated that each of the PAICs were amorphous and had glass transition temperatures ranging from50to115°*** analyses found Td‐5%values ranging from316to332°C for these *** on these data,it is evident that the incorporation of linear or cyclohexane‐based diol repeating units changed the thermal properties of the PIC.

摘要：Metal chalcogenide compounds can be used as high-performance cathodes for aqueous Zn ***,the low accessible surfaces and violent volumetric expansion limit their properties and *** address these,phase-engineering strategies coupled with a hollow structure were applied to regulate the adsorption/desorption of OH−on the electrode surface and enhance the electrochemical *** this study,using a Se@C nanorod template,a series of carbon nanotube(CNT)-supported nickel selenides,including cubic NiSe_(2),NiSe_(2)/Ni_(0.85)Se composites,and hexagonal Ni_(0.85)Se,were synthesized through an in situ selenylation process for the first *** to the large specific surface,high porosity,and hollow carbon skeleton,the optimized NiSe_(2)/Ni_(0.85)Se/CNT has a high specific capacity of 616 Cg^(−1),excellent rate capability,and stable cycling *** addition,its inside Faradic mechanism was investigated using a series of ex situ characterizations and density functional theory ***,the fabricated Ni//Zn battery presents a high energy density of 311.4 W h kg^(−1) at 3485 W kg^(−1) and long cycling *** study offers an ingenious strategy for designing nickel selenide electrodes and deeper perception for its Faradic mechanism in alkaline Zn battery.

摘要：The extending of a cantilever and transverse moving of a drilling floor enable the jack-up to operate in several well positions after the Jack-up has pitched. The cantilever allowable load nephogram is the critical reference which can evaluate the jack-up's drilling ability, design the cantilever structure and instruct a jack-up manager to make the operations safe. The intent of this paper is to explore the interrelationships between the cantilever position, drilling floor and the loads including wind force, the stand set-back weight etc., through analyzing the structure and load characteristics of the x-type cantilever and the simplified mechanics model with the restriction of the maximum moment capacity of the cantilever single side beam. Referring to several typical position designs load values, the cantilever allowable load nephogram is obtained by using the suitable interpolation method. The paper gives a method for cantilever allowable load design, which is proved reliable and effective by the calculation example.

摘要：Single-atom catalysts(SACs) with well-defined and specific single-atom dispersion on supports offer great potential for achieving both high catalytic activity and selectivity. Covalent organic frameworks(COFs) with tailormade crystalline structures and designable atomic composition is a class of promising supports for SACs. Herein, we have studied the binding sites and stability of Pd single atoms(SAs)dispersed on triazine COF(Pd1/trzn-COF) and the reaction mechanism of CO oxidation using the density functional theory(DFT). By evaluating different adsorption sites, including the nucleophilic sp2C atoms, heteroatoms and the conjugated π-electrons of aromatic ring and triazine, it is found that Pd SAs can stably combine with trzn-COF with a binding energy around-5.0 eV, and there are two co-existing dynamic Pd1/trzn-COFs due to the adjacent binding sites on trzn-COF. The reaction activities of CO oxidation on Pd1/trzn-COF can be regulated by the anion–π interaction between a +δ phenyl center and the related-δ moieties as well as the electron-withdrawing feature of imine in the specific complexes. The Pd1/trzn-COF catalyst is found to have a high catalytic activity for CO oxidation via a plausible tri-molecular Eley-Rideal(TER) reaction mechanism. This work provides insights into the d–π interaction between Pd SAs and trznCOF, and helps to better understand and design new SACs supported on COF nanomaterials.

摘要：The development of new products of high quality, low unit cost, and short lead time to market are the key elements required for any enterprise to obtain a competitive advantage. This part of the paper presents a methodology to automatically simulate the conceptual design results in the virtual entity form. To the identified basic mechanisms, their kinematic analysis is carried out by matching basic Barranov trusses, and their virtual entities are modeled based on feature-based technique and encapsulated as one design object. Based on the structures of the basic mechanisms and their connections, a space layout to the mechanical system corresponding to the symbolic scheme is then fulfilled. With the preset-assembly approach, all parts in the mechanical system are put onto proper positions where the constraint equations are met according to the space layout results. In this way, the virtual entity assembly model of the mechanical system relative to the symbolic scheme is set up. The approach presented in this paper can not only obtain innovative conceptual conceptual design results, but also can evaluate their performances under 3-D enviroment efficently.

摘要：The development of new products of high quality, low unit cost, and short lead time to market are the key elements required for any enterprise to obtain a competitive advantage. For shorting the lead time to market and improving the creativity and performances of the product, a rule-based conceptual design approach and a methodology to simulate the conceptual design results generated in conceptual design process in automatical virtual entity form are presented in this paper. This part of paper presents a rule-based conceptual design method for generating creative conceptual design schemes of mechanisms based on Yan＇s kinematic chain regeneration creative design method. The design rules are adopted to describe the design requirements of the functional characteristics, the connection relationships and topological characteristics among mechanisms. Through the graphs-based reasoning process, the conceptual design space is expanded extremely, and the potential creative conceptual design results are then dug out. By refining the design rules, the solution exploration problem is avioded, and the tendentious conceptual design schemes are generated. Since mechanical, electrical and hydraulic subsystems can be transformed into general mechansims, the conceptual design method presented in this paper can also be applied in the conceptual design problem of complex mechatronic systems. And then the method to identify conceptual design schemes is given.