摘要：The paper presented topology optimization of 2 D and 3 D Nanofluid-Cooled Heat Sink(NCHS). The flow and heat transfer problem in the NCHS was treated as a single-phase nanofluid based convective heat transfer model. The temperature-dependent fluid properties were taken into account in the model due to the strong temperature-dependent features of nanofluids. An average temperature minimum problem was studied subject to the fluid area and energy dissipation constraints by using the density method. In the method, the design variable is updated according to the gradient information obtained by an adjoint based sensitivity analysis process. The effects of the energy dissipation constraint, temperature-dependent fluid properties and nanofluid characteristics on optimal configurations of NCHS were numerically investigated with following ***, branched flow channels in the optimal configuration increased with the rise of the allowed energy dissipation. Secondly, temperature-dependent fluid properties were significant for obtaining the appropriate optimal results with best cooling performance. Thirdly, heat transfer performances of optimal configurations were enhanced by reducing the nanoparticle diameter or increasing the nanoparticle volume fraction. Fourthly, the optimal configuration for nanofluid had better cooling performance than that for its base fluid.

摘要：Ideal tissue engineering scaffolds need interconnected pores and high porosity to enable cell survival,migration,proliferation,and ***,obtaining a high-resolution structure is difficult with traditional one-temperature control fused deposition modeling(FDM).In this study,we propose a dual-temperature control method to improve printability.A numerical model is developed in which the viscosity is a function of temperature and shear rate to study the influence of two different temperature control *** tests are used to assess filament formation and shape fidelity,including one-dimensional filament printing,deposition at corners,fusion,and *** using dual-temperature control,the width of the deposited poly(ε-caprolactone)filament is reduced to 50μ*** comparative results of both the experimental method and numerical simulation suggest that the dual-temperature control FDM can manufacture spatially arranged constructs and presents a promising application in tissue engineering。

摘要：Recently,Kelly and colleagues[1],inspired by computed tomography(CT),report a“volumetric additive manufacturing”technology via a computed axial lithography(CAL)approach.A related US patent application[2]has also been *** cumulative light exposure solidifies the material in the target area,while the other area remains uncured,resulting in only specific points in the designed 3D objects being *** technology significantly improves the capability of the digital light processing(DLP)***,the lithography approach based on a similar algorithm was already proposed by Xiang Wu in a patent(application ***/CN2016/080097)in 2016[3].

摘要：Cancer is characterized by a high fatality rate,complex molecular mechanism,and costly *** microenvironment of a tumor consists of multiple biochemical cues and the interaction between tumor cells,stromal cells,and extracellular matrix plays a key role in tumor initiation,development,angiogenesis,invasion and *** better understand the biological features of tumor and reveal the critical factors of therapeutic treatments against cancer,it is of great significance to build in vitro tumor models that could recapitulate the stages of tumor progression and mimic tumor behaviors in vivo for efficient and patient-specific drug screening and biological *** conventional tissue engineering methods of constructing tumor models always fail to simulate the later stages of tumor development due to the lack of ability to build complex structures and angiogenesis potential,three-dimensional(3D)bioprinting techniques have gradually found its applications in tumor microenvironment modeling with accurate composition and well-organized spatial distribution of tumor-related cells and extracellular components in the past *** capabilities of building tumor models with a large range of scale,complex structures,multiple biomaterials and vascular network with high resolution and throughput make 3D bioprinting become a versatile platform in bio-manufacturing aswell as inmedical *** this review,wewill focus on 3D bioprinting strategies,design of bioinks,current 3D bioprinted tumor models in vitro classified with their structures and propose future perspectives.

摘要：With a growing population, an increasing number of petrochemical facilities are built with larger capacity and more complexity, which pose a great risk to assets, community and environment. The value of inherently safer design is recognized with time by all stakeholders, and an effective tool is needed to evaluate and compare inherent safety of alternative technologies. This study developed a safety index to evaluate existing technologies for their safety levels and guide inherently safer design. The Integrated Risk-based Safety Index(IRSI) was developed based on a comprehensive review of petrochemical processes, incident cases from Sinopec and US Chemical Safety Board, and existing safety index systems. The IRSI included all major hazards, including fire, explosion,toxic release, dust explosion, physical explosion, and runaway. Also, the integrated life cycle approach considered chemical hazards, equipment failure rates and safety measures in this risk-based index. Advanced modeling techniques, PHAST simulation and Neural Network, were used in the development of three novel sub-indices in the projects, fire, explosion and toxic release. The index system could be easily incorporated into a user friendly tool for the ease of application. A case study of hydrogen dioxide was conducted using the IRSI, which showed its capability for evaluating the safety level of process facilities.

摘要：A novel simulation method for fuze warhead system (FWS) at very low altitude flight is proposed to solve adaptability issues of the traditional one in the naval battle. Firstly, a simulation system framework is presented. Then the detailed implementation of a novel general fuze model, a novel sea echo model and a novel warhead dynamic effectiveness power field algorithm including the simulation system are presented. Finally, simulation results show good performance of the proposed method. The proposed method can simulate the echo signal when the complex fuze antennas detect target and the sea at the same time, and can truly reflect the target positions hit by the warhead fragments. The proposed method can solve the existing problems in the FWS simulation system.

摘要：Bioprinting:a powerful tool to fabricate biomimetic tissues and organs Bioprinting is an important technology in the field of biofabrication that aims to create functional biomimetic *** flexibility,versatility and functionality of bioprinting enable the fabrication of intricate biological structures by combining cells,biomaterials or growth factors as printing bioinks[1,2].

摘要：Compared to the current eddy braking patterns using a single magnetic source,hybrid excitation rail eddy brakes have many advantages,such as controllability,energy saving,and various operating *** the large braking power consumption of the high-speed train,a hybrid excitation rail eddy brake system,which is based on the principle of electromagnetic field,is proposed to fulfill the needs of safety and *** the working processes of the mechanical lifting system and electromagnetic system are *** the electromagnetic system analyzed using the finite element method,the factors such as speed,air gap,and exciting current have influences on the braking force and attractive *** last,the structure optimization of the brake system is discussed.

摘要：Treatments for lesions in central nervous system(CNS)are always faced with challenges due to the anatomical and physiological particularity of the CNS despite the fact that several achievements have been made in early diagnosis and precision medicine to improve the survival and quality of life of patients with brain tumors in recent *** the complexity as well as role of the microenvironment of brain tumors may suggest a better revealing of the molecular mechanism of brain tumors and new therapeutic directions,which requires an accurate recapitulation of the complex microenvironment of human brain in ***,a 3D bioprinted in vitro brain matrix-mimetic microenvironment model with hyaluronic acid(HA)and normal glial cells(HEBs)is developed which simulates both mechanical and biological properties of human brain microenvironment in vivo through the investigation of the formulation of bioinks and optimization of printing process and parameters to study the effects of different concentration of gelatin(GA)within the bioink and different printing structures of the scaffold on the performance of the brain matrix-mimetic microenvironment *** study provides experimental models for the exploration of the multiple factors in the brain microenvironment and scaffolds for GBM invasion study.

摘要：Vladimir Vladimirovich Nabokov （1899-1977）, a Russian-born Ameri- can writer, is one of the most gifted exilic writers of the twentieth century. His first English novel, The Real Life of Sebastian Knight, which inherits certain aesthetic motifs of his Russian works, such as the artist in exile, the motif of the double, and the theme of the other world, has attracted the academic circle and received extreme views spreading between the good and the bad. But the core question in the whole of Nabokov scholarship is the ambiguous identities of the novel＇s two heroes, Sebastian and V. who are half-brothers. It is the identity puzzle that makes this novel more and more popular in Nabokov criticism. This essay attempts to review past reviews concerning this problem and analyze the four interpretations occa- sioned by the identity puzzle in Nabokov criticism.