检索结果-南通市图书馆

Ultra-fast polymer optical fibre Bragg grating inscription for medical devices

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2017年第1期6卷 104-113页

作者： Julien Bonefacino Hwa-Yaw Tam Tom S Glen Xin Cheng Chi-Fung Jeff Pun Jian Wang Po-Heng Lee Ming-Leung Vincent Tse Steven T Boles Photonics Research Centre Department of Electrical EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Division of Urban Environment Department of Civil and Environmental EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

We report the extraordinary result of rapid fibre Bragg grating inscription in doped polymer optical fibres based on polymethyl methacrylate in only 7 ms,which is two orders of magnitude faster than the inscription times previously *** was achieved using a new dopant material,diphenyl disulphide,which was found to enable a fast,positive refractive index change using a low ultraviolet *** changes were investigated and found to arise from photodissociation of the diphenyl disulphide molecule and subsequent molecular *** demonstrate that gratings inscribed in these fibres can exhibit at least a 15 times higher sensitivity than silica glass fibre,despite their quick inscription *** a demonstration of the sensitivity,we selected a highly stringent situation,namely,the monitoring of a human heartbeat and respiratory *** findings could permit the inscription of fibre Bragg gratings during the fibre drawing process for mass production,allowing costeffective,single-use,in vivo sensors among other potential uses.

关键词： bio-sensing fibre Bragg grating photosensitive dopant polymer optical fibre

Recent Advances on Electrospun Nanofiber Materials for Post-lithium Ion Batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advanced Fiber Materials 2021年第5期3卷 275-301页

作者： Fangyi Shi Chunhong Chen Zheng-Long Xu department of Industrial and Systems engineering The Hong Kong Polytechnic UniversityHung HomHong KongPeople’s Republic of China department of Applied Physics The Hong Kong Polytechnic UniversityHung HomHong KongPeople’s Republic of China

Lithium ion batteries(LIBs)have dominated the portable electric market over decades;however,the limited and unevenly distributed lithium resources induce concerns on their future large-scale *** efforts have been endeavored on exploring post-Li ion batteries,such as Na-ion,K-ion,Al-ion and Mg-ion batteries,due to the high abundance of the corresponding elements in Earth *** reliable electrode materials is the key to develop these new battery *** and scalable electrospinning has been widely utilized in preparing mechanically stable,flexible and conductive nanofiber electrodes as successfully proven in *** recent years,tremendous efforts have been devoted to electrospinning nanofiber electrodes for post-Li ion batteries and discernible progress in the electrochemical performance has been ***,we aim to review the-state-of-the-art advances made in electrospun nanofiber materials in optimizing post-Li ion battery technology by surveying the correlations among the morphology,the surface chemistry,the structure of electrospun nanofibers,and the post-Li ion batteries *** on intensive investigations and insightful understandings,perspectives to the future design of electrospun nanofiber electrodes are also presented.

关键词： Electrospinning Nanofibers Electrodes Post-li ion batteries

An extraordinary-performance gradient nanostructured Hadfield manganese steel containing multi-phase nanocrystalline-amorphous core-shell surface layer by laser surface processing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第3期134卷 209-222页

作者： Wanting Sun Jiasi Luo Yim Ying Chan J.H.Luan Xu-Sheng Yang Research Institute for Advanced Manufacturing Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomHong KongChina hong kong Branch of National Rail Transit Electrification and Automation engineering Technology Research Center The Hong Kong Polytechnic UniversityHung HomHong KongChina department of Materials Science and engineering City University of Hong KongHong KongChina

Reducing grain size(*** the fraction of grain boundaries)could effectively strengthen nanograined metals but inevitably sacrifices the ductility and possibly causes a strengthening-softening transition below a critical grain *** this work,a facile laser surface remelting-based technique was employed and optimized to fabricate a∼600μm-thick heterogeneous gradient nanostructured layer on an austenitic Hadfield manganese steel,in which the average grain size is gradually decreased from∼200μm in the matrix to only∼8 nm in the nanocrystalline-amorphous core-shell topmost ***-scale microstructural characterizations dissected the gradient refinement processes along the gradient direction,*** from the dislocations activities and twinning in sub-region to three kinds of martensitic transformations,and finally a multi-phase nanocrystalline-amorphous core-shell structural *** tests(***,bulk-specimen tensile,and micro-pillar compression)were conducted along the gradient *** confirms a tensile strength of∼1055 MPa and ductility of∼10.5%in the laser-processed ***,the core-shell structural surface maintains ultra-strong(tensile strength of∼1.6 GPa,micro-pillar compressive strength of∼4 GPa at a strain of∼8%,and nanoindentation hardness of∼7.7 GPa)to overcome the potential strengthening-softening *** significant strengthening effects are ascribed to the strength-ductility synergetic effects-induced extra work hardening ability in gradient nanostructure and the well-maintained dislocation activities inside extremely refined nanograins in the multi-phase nanocrystalline-amorphous core-shell structural surface,which are evidenced by atomic-scale observations and theoretical *** study provides a unique hetero-nanostructure through a facile laser-related technique for extraordinary mechanical performance.

关键词： Laser surface processing Hadfield manganese steel Gradient nanostructure Nanocrystalline-amorphous Martensitic transformation

Tree‑Inspired Structurally Graded Aerogel with Synergistic Water,Salt,and Thermal Transport for High‑Salinity Solar‑Powered Evaporation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第11期16卷 19-37页

作者： Xiaomeng Zhao Heng Zhang Kit‑Ying Chan Xinyue Huang Yunfei Yang Xi Shen department of Aeronautical and Aviation engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARPeople’s Republic of China Research Institute for Sports Science and Technology The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARPeople’s Republic of China Research Institute for Advanced Manufacturing The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARPeople’s Republic of China

Solar-powered interfacial evaporation is an energy-efficient solution for water *** requires solar absorbers to facilitate upward water transport and limit the heat to the surface for efficient ***,downward salt ion transport is also desired to prevent salt ***,achieving simultaneously fast water uptake,downward salt transport,and heat localization is challenging due to highly coupled water,mass,and thermal ***,we develop a structurally graded aerogel inspired by tree transport systems to collectively optimize water,salt,and thermal *** arched aerogel features root-like,fan-shaped microchannels for rapid water uptake and downward salt diffusion,and horizontally aligned pores near the surface for heat localization through maximizing solar absorption and minimizing conductive heat *** structural characteristics gave rise to consistent evaporation rates of 2.09 kg m^(-2) h^(-1) under one-sun illumination in a 3.5 wt%NaCl solution for 7 days without *** in a high-salinity solution of 20 wt%NaCl,the evaporation rates maintained stable at 1.94 kg m^(-2) h^(-1) for 8 h without salt crystal *** work offers a novel microstructural design to address the complex interplay of water,salt,and thermal transport.

关键词： Composite aerogel Graded structure Solar-powered evaporation Thermal insulation Salt rejection

Analytical Method for Designing Grating Compensated Dispersion-Managed Soliton Systems

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

光学学报 2003年第S1期23卷 655-656页

作者： Y. H. C. Kwan K. Nakkeeran P. K. A. Wai Photonics Research Centre and department of electronic and Information engineering The Hong Kong Polytechnic University Hung Hom Hong KongPhotonics Research Centre and Department of Electronic and Information Engineering The Hong Kong Polytechnic University Hung Hom Hong KongPhotonics Research Centre and Department of Electronic and Information Engineering The Hong Kong Polytechnic University Hung Hom Hong Kong

We show a useful analytical method to design grating compensated dispersion-managed systems. Our method is in good agreement with the numerical results even in the presence of group delay ripples in the chirped fiber ... 详细信息

关键词： for in FWHM In of GDR Analytical Method for Designing Grating Compensated Dispersion-Managed Soliton Systems

Large Eddy Simulation of Turbulent Channel Flow with 3D Roughness Using a Roughness Element Model

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2008年第1期25卷 191-194页

作者：杨帆张会强陈昌麒王希麟 department of engineering Mechanics Tsinghua University Beijing 100084 department of Applied Mathematics The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong

Large eddy simulation of turbulent channel flow with dense and small 3D roughness elements is carried out using a roughness element model Profiles of mean Reynolds stress, mean velocity and rms velocity as well as turbulent structures near the wall are obtained. The shear stress in the rough wall is larger than that in the smooth wall side and the rough wall has a larger influence on the channel flow. Profiles of mean streamwise velocity near the wall have logarithmic velocity distributions for both smooth and roughness walls, while there is a velocity decrease for the rough wall due to larger fractional drag. All the three components of rms velocities in the rough wall region are larger than that in the smooth wall region, and the roughness elements on the wall increase turbulent intensity in all directions. The s^reak spacing and average diameter of near wall quasi-s^reamwise vortices increase with the presence of roughness elements on the wall and it is shown that the rough wall induces complex and strong streamwise vortices. Results of dense and small 3D roughness elements in both turbulent statistics and structure, obtained with a relatively simple method, are found to be comparable to related experiments.

关键词： BOUNDARY-LAYERS WALL

Graphene and MXene-based porous structures for multifunctional electromagnetic interference shielding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第1期16卷 1387-1413页

作者： Xi Shen Jang-Kyo Kim department of Aeronautical and Aviation engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong 999077China School of Mechanical and Manufacturing engineering University of New South WalesSydneyNSW 2052Australia The Research Institute for Sports Science and Technology The Hong Kong Polytechnic UniversityHung HomHong Kong 999077China

Electrically conductive porous structures are ideal candidates for lightweight and absorption-dominant electromagnetic interference(EMI)*** this review,we summarize the recent progress in developing porous composites and structures from emerging two-dimensional(2D)graphene and MXene nanosheets for EMI shielding *** properties contributing to various energy loss mechanisms are probed with a critical discussion on their correlations with EMI shielding *** approaches to constructing bulk porous structures,such as 2D porous films,three-dimensional(3D)aerogels and foams,and hydrogels,are compared to highlight important material and processing parameters required to achieve optimal microstructures.A comprehensive comparison of EMI shielding performance is also carried out to elucidate the effects of different assembly techniques and *** multifunctional applications in adaptive EMI shielding,mechanical force attenuation,thermal management,and wearable devices are introduced,underlining the importance of unique compositions and microstructures of porous *** process–structure–property relationships established in this review would offer valuable guidance and insights into the design of lightweight EMI shielding materials.

关键词： porous composite graphene MXene electrical conductivity electromagnetic interference(EMI)shielding

Machine learning for advanced energy materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and AI 2021年第1期3卷 22-48页

作者： Yun Liu Oladapo Christopher Esan Zhefei Pan Liang An department of Mechanical engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARChina

The screening of advanced materials coupled with the modeling of their quantitative structural-activity relation-ships has recently become one of the hot and trending topics in energy materials due to the diverse challenges,including low success probabilities,high time consumption,and high computational cost associated with the traditional methods of developing energy *** this,new research concepts and technologies to promote the research and development of energy materials become *** latest advancements in ar-tificial intelligence and machine learning have therefore increased the expectation that data-driven materials science would revolutionize scientific discoveries towards providing new paradigms for the development of en-ergy ***,the current advances in data-driven materials engineering also demonstrate that the application of machine learning technology would not only significantly facilitate the design and development of advanced energy materials but also enhance their discovery and *** this article,the importance and necessity of developing new energy materials towards contributing to the global carbon neutrality are presented.A comprehensive introduction to the fundamentals of machine learning is also provided,including open-source databases,feature engineering,machine learning algorithms,and analysis of machine learning ***,the latest progress in data-driven materials science and engineering,including alkaline ion battery materials,pho-tovoltaic materials,catalytic materials,and carbon dioxide capture materials,is ***,relevant clues to the successful applications of machine learning and the remaining challenges towards the development of advanced energy materials are highlighted.

关键词： Energy materials Artificial intelligence Machine learning Data-driven materials science and engineering Prediction of materials properties Design and discovery of energy materials

Structural design and mechanical performance of composite vascular grafts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bio-Design and Manufacturing 2022年第4期5卷 757-785页

作者： Abdul Wasy Zia Rong Liu Xinbo Wu School of Fashion and Textiles The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARChina

This study reviews the state of the art in structural design and the corresponding mechanical behaviours of composite vascular grafts. We critically analyse surface and matrix designs composed of layered, embedded, and hybrid structures along the radial and longitudinal directions;materials and manufacturing techniques, such as tissue engineering and the use of textiles or their combinations;and the corresponding mechanical behaviours of composite vascular grafts in terms of their physical–mechanical properties, especially their stress–strain relationships and elastic recovery. The role of computational studies is discussed with respect to optimizing the geometrics designs and the corresponding mechanical behaviours to satisfy specialized applications, such as those for the aorta and its subparts. Natural and synthetic endothelial materials yield improvements in the mechanical and biological compliance of composite graft surfaces with host arteries. Moreover,the diameter, wall thickness, stiffness, compliance, tensile strength, elasticity, and burst strength of the graft matrix are determined depending on the application and the patient. For composite vascular grafts, hybrid architectures are recommended featuring multiple layers, dimensions, and materials to achieve the desired optimal flexibility and function for complying with user-specific requirements. Rapidly emerging artificial intelligence and big data techniques for diagnostics and the threedimensional(3D) manufacturing of vascular grafts will likely yield highly compliant, subject-specific, long-lasting, and economical vascular grafts in the near-future.

关键词： Vascular grafts Surface design Structural design Composite materials Mechanical properties