摘要：Electron beam lithography(EBL) is a key technology in the fabrication of nanoscale silicon optical waveguide. The influence of exposure dose, the main process parameter of EBL, on the structure profile of poly-methyl methacrylate(PMMA) after development was studied using a silicon on insulator(SOI) wafer with 220 nm top silicon as the substrate. The relationship between exposure dose and structure pattern width after development was analyzed according to the measurement results. The optimum exposure dose of 220 μC/cm^(2) was found to obtain a final structure consistent with the designed mask value through subsequent processes. At the same time, according to the image segmentation curve tracking technology, the contour extraction process of the dose test results was carried out, and the relationship among mask design value, exposure dose and two-dimensional roughness of boundary contour was analyzed, which can provide reference for the subsequent electron beam lithography of the same substrate material.

摘要：In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.

摘要：Laser powder bed fusion(LPBF)makes it possible for biodegradable zinc(Zn)to be used to produce customized orthopedic *** this research,we investigate the impact of laser power and scanning speed on the development of surface quality,relative densification,and texture during LPBF of Zn *** laser power was able to decrease melt viscosity and surface tension,which improved the metallurgical bonding between adjacent *** and twisted tracks also became continuous and *** speed could controlmolten-pool temperature to restrain grain natural orientation,achieving various crystal orientations and a weakened ***,it further avoided the thermal expansion and contraction caused by excessive energy storage and accumulation in the matrix,thus reducing the generation of high-dislocation *** a result,by selecting a reasonable laser power and scanning speed,the LPBF parts exhibited a flat surface morphology and a high density over 99.5%.Their average hardness,mechanical strength,and elongation reached 50.2 HV,127.8 MPa,and 7.6%,***,the parts displayed a moderate degradation rate and excellent osteogenic *** these results provide a basis for selecting process parameters to optimize the comprehensive properties of LPBF-processed Zn parts for biodegradable applications.

摘要：The layout of the buckets for tunnel boring machine(TBM)directly affects the muck removal efficiency of cutterhead during *** order to improve the muck removal performance for TBM,the optimal design of bucket layout was *** whole muck transfer process was simulated by discrete-element method(DEM),including the muck falling,colliding,pilling up,shoveling and transferring into the *** muck model was established based on size distribution analysis of muck samples from the water-supply tunnel project in Jilin Province,***,the influence of the bucket number and the interval angle between buckets on muck removal performance was *** results indicated that,as the number of buckets increased from four to eight,the removed muck increased by 29%and the residual volume decreased by 40.5%,and the process became *** interval angles between buckets were corresponding to different removed muck irregularly,but the residual muck number increased generally with the *** optimal layout of buckets for the cutterhead in this tunnel project was obtained based on the simulation results,and the muck removal performance of the TBM was verified by the actual data in the engineering construction.

摘要：The preparation of superhydrophobic or underwater superoleophobic interface materials has become a research hotspot because of their wide application in self-cleaning, drag reduction, oil-water separation, anti-oil pollution and so on. The unique wettability of organisms gives inspiration to design and create new interface materials. This review focuses on the recent research progress of femtosecond laser micro/nano fabrication for bioinspired superhydrophobic or underwater superoleophobic surfaces. This review starts with a presentation of the related background including the advantages of femtosecond laser and wettability theoretical basis. Then, organisms with unique wettability in nature, the preparation of superhydrophobic or underwater superoleophobic surfaces by femtosecond lasers on different materials, and their related important applications are introduced. Finally, the current challenges and future prospects with regard to this field are provided.

摘要：A new consistency control method for jet dispensing is proposed. First, the working parameters, namely, viscosity, supply pressure and supply time, are experimentally investigated. Then, the glue viscosity is approximated by a polynomial model using the least square method. Based on this model and temperatme control implemented using the Dahlin principle, the viscosity of the glue can be maintained at a constant value. Then, the viscosity model of the glue is applied to deriving the droplet mass as the nominal model of the temperature controller. The robustness of the temperature controller is analyzed by applying the small gain theory. The glue supply pressure controller is designed using the consistency control strategy, and the robustness is analyzed. Finall）, simulations and experiments are conducted using a jet dispensing control system. The results show that the proposed control strategy can significantly improve the droplet consistency.

摘要：Geological adaptability matching design of a disc cutter is the prerequisite of cutter head design for tunnel boring machines(TBMs)and plays an important role in improving the tunneling efficiency of *** main purpose of the cutter matching design is to evaluate the cutter performance and select the appropriate cutter *** this paper,a novel evaluation method based on multicriteria decision making(MCDM)techniques was developed to help TBM designers in the process of determining the cutter *** analytic hierarchy process(AHP)and matter element analysis were applied to obtaining the weights of the cutter evaluation criteria,and the fuzzy comprehensive evaluation and technique for order performance by similarity to ideal solution(TOPSIS)approaches were employed to determine the ranking of the cutters.A case application was offered to illustrate and validate the proposed *** results of the project case demonstrate that this method is reasonable and feasible for disc cutter size selection in cutter head design.

摘要：There have been a great demand for a suitable and convenient method in the field of buckling analysis of stiffened ship structures, which is essential to structural safety assessment and is significantly time-consuming. Modeling, buckling behaviors and ultimate strength prediction of stiffened panels were investigated. The modeling specification including nonlinear finite element model and imperfections generation, and post-buckling analysis procedure of stiffened plates were demonstrated. And a software tool using set-based finite element method was developed and executed in the MSC. Marc environment. Different types of stiffen panels of marine structures have been employed to investigate the buckling behavior and assess the validity in the estimation of ultimate strength. A comparison between results of the generally accepted methods, experiments and the software tool developed was demonstrated. It is shown that the software tool can predict the ultimate capacity of stiffened panels with imperfections with a good accuracy.

摘要：As two promising biomaterials for bone implants,biomedical metals have favorable mechanical properties and good machinability but lack of bioactivity;while bioceramics are known for good biocompatibility or even bioactivity but limited by their high ***,a kind of composites composing of bioceramics and biomedical metals,have been developed as an effective solution by combining their complementary *** paper focused on the recently studied biocermets for bone implant ***,biocermets were divided into ceramic-based biocermets and metal-based biocermets according to the phase *** characteristics were systematically summarized,and the fabrication methods for biocermets were reviewed and *** were put on the interactions between bioceramics and biomedical metals,as well as the performance improvement *** importantly,the main methods for the interfacial reinforcing were summarized,and the corresponding interfacial reinforcing mechanisms were *** addition,the in vitro and in vivo biological performances of biocermets were also ***,future research directions were proposed on the advancement in component design,interfacial reinforcing and forming mechanisms for the fabrication of high-performance biocermets.

摘要：Stepped heating treatment has been applied to aluminum alloy thick plate to improve the mechanical performance and corrosion *** temperature control of the plate is the difficulty in engineering *** heating process,the calculation of surface heat transfer coefficient and the accurate temperature control method were studied based on measured heating temperature for the large-size thick *** results show that,the temperature difference between the surface and center of the thick plate is *** on the temperature uniformity,the surface heat transfer coefficient was calculated,and it is constant below300°C,but grows greatly over300°***,a lumped parameter method(LPM)was developed to predict the plate temperature.A stepped solution treatment was designed by using LPM,and verified by finite element method(FEM)and *** curves calculated by LPM and FEM agree well with the experimental data,and the LPM is more convenient in engineering application.