Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hie...Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hierarchical micro/nanograting structures is important for these applications.In this study,a strategy for machining hierarchical micro/nanograting structures is developed by controlling the tool movement trajectory.A coupling Euler-Lagrange finite element model is established to simulate the machining process.The effect of the machining methods on the nanograting formation is demonstrated,and a suitable machining method for reducing the cutting force is obtained.The height of the nanograting decreases with an increase in the tool edge radius.Furthermore,optical variable devices(OVDs)are machined using an array overlap machining approach.Coding schemes for the parallel column unit crossover and column unit in the groove crossover are designed to achieve high-quality machining of OVDs.The coloring of the logo of the Harbin Institute of Technology and the logo of the centennial anniversary of the Harbin Institute of Technology on the surface of metal samples,such as aluminum alloys,is realized.The findings of this study provide a method for the fabrication of hierarchical micro/nanograting structures that can be used to prepare OVDs.展开更多
A combination of the loosely and compactly coupled integrations of CAD tools and its applications in the design and fabrication of surface acoustic wave (SAW) devices are proposed in this paper. Three core modules are...A combination of the loosely and compactly coupled integrations of CAD tools and its applications in the design and fabrication of surface acoustic wave (SAW) devices are proposed in this paper. Three core modules are developed as design and mask pattern verification module,database module, and device characteristics simulation module. All the operations are controlled under Microsoft Windows GUI interface. This leads to a reduced design and fabrication cycle, workload and cost. With the knowledge-based library for intelligent design and Lotus Notes database for distributed and networked engineering database management (EDM) and effective control of documents, a new enterprise-leveled, computer-integrated design and manufacturing system (CIDMS)can be established for monolithic and hybrid device design (not only confined to SAW device).展开更多
To increase the machine accuracy by improving the stiffness of bearings,a preload was applied to bearings.A variable preload technology was necessary to perform machining processes in both low and high speed regions.A...To increase the machine accuracy by improving the stiffness of bearings,a preload was applied to bearings.A variable preload technology was necessary to perform machining processes in both low and high speed regions.An automatic variable preload device was fabricated using an eccentric mass.By installing the fabricated device on a spindle,the effect of the automatic variable preload device on the performance of the spindle was analyzed.In the results of the vibration measurement of the spindle,the vibration is increased by 20%-37% according to measurement points at the maximum rotation speed of 5 000 r/min.And,in the results of the noise measurement of the spindle,the spindle rotation speed is increased by about 1.9% and 1.5% at the front and side of the spindle,respectively.Based on the results of this analysis,an improved method that reduces such effects on the performance of the spindle is proposed.展开更多
In order to prevent unwanted excited vibrations and to secure better machining precision in large size heavy duty machine tools dynamic stiffness is one of the most desirable and critical properties. In the past decad...In order to prevent unwanted excited vibrations and to secure better machining precision in large size heavy duty machine tools dynamic stiffness is one of the most desirable and critical properties. In the past decades, many researches on machine tool stiffness test and evaluation methodology have been made. However any methodology for a Pin Turning Device (PTD), which is a special kind of turning lathe for machining big size crankshaft pins, is rarely found among them. This study proposes a test and evaluation process of stiffness of a PTD by measuring frequency response function at the tool center point (TCP). For conformance proving for the proposed methodology, stiffness of a PTD obtained by the proposed method with impact hammer test (IHT) has been compared with that determined by FEM.展开更多
An individual's mental health influences their capacity to think effectively,feel emotionally stable,and perform daily activities.As mental health concerns become more prevalent worldwide,new awareness and diagnos...An individual's mental health influences their capacity to think effectively,feel emotionally stable,and perform daily activities.As mental health concerns become more prevalent worldwide,new awareness and diagnostic and treatment tactics are needed.Digital tools and technology are helping solve these problems by providing scalable,tailored solutions for large populations.This detailed review examines mental health‐promoting internet tools.Smartphone applications,web‐based therapy systems,wearable tech,artificial intelligence‐powered resources,and virtual reality(VR)technologies were evaluated for efficacy and side effects.PubMed,PsycINFO,Scopus,IEEE Xplore,and Google Scholar were carefully searched.Search terms included“digital mental health tools,”“online therapy,”and“AI in mental health.”Randomized controlled trials,cohort studies,cross‐sectional studies,systematic reviews,and meta‐analyses of digital technology and mental health were included from among the literature published after 2010.Cognitive behavioral therapy methods,mood monitoring,and mindfulness exercises are among the numerous features of smartphone applications that have been demonstrated to mitigate symptoms of anxiety,depression,and tension.Online therapy platforms let marginalized individuals obtain therapy remotely.Wearable technology may detect heart rate,blood pressure,and sleep length,which may reveal mental health difficulties.Chatbots employ machine learning algorithms and natural language processing to deliver customized support and show promise for quick intervention.Exposure therapy for anxiety and trauma is increasingly using virtual reality environments.Although digital mental health therapies face challenges in relation to data privacy,limited long‐term efficacy,and technological inequality,digital technologies are modernizing mental healthcare.By offering inexpensive and effective alternatives to traditional therapies,digital technologies may help healthcare systems meet the growing demand for mental health services and overall well‐being.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52035004,52105434).
文摘Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hierarchical micro/nanograting structures is important for these applications.In this study,a strategy for machining hierarchical micro/nanograting structures is developed by controlling the tool movement trajectory.A coupling Euler-Lagrange finite element model is established to simulate the machining process.The effect of the machining methods on the nanograting formation is demonstrated,and a suitable machining method for reducing the cutting force is obtained.The height of the nanograting decreases with an increase in the tool edge radius.Furthermore,optical variable devices(OVDs)are machined using an array overlap machining approach.Coding schemes for the parallel column unit crossover and column unit in the groove crossover are designed to achieve high-quality machining of OVDs.The coloring of the logo of the Harbin Institute of Technology and the logo of the centennial anniversary of the Harbin Institute of Technology on the surface of metal samples,such as aluminum alloys,is realized.The findings of this study provide a method for the fabrication of hierarchical micro/nanograting structures that can be used to prepare OVDs.
文摘A combination of the loosely and compactly coupled integrations of CAD tools and its applications in the design and fabrication of surface acoustic wave (SAW) devices are proposed in this paper. Three core modules are developed as design and mask pattern verification module,database module, and device characteristics simulation module. All the operations are controlled under Microsoft Windows GUI interface. This leads to a reduced design and fabrication cycle, workload and cost. With the knowledge-based library for intelligent design and Lotus Notes database for distributed and networked engineering database management (EDM) and effective control of documents, a new enterprise-leveled, computer-integrated design and manufacturing system (CIDMS)can be established for monolithic and hybrid device design (not only confined to SAW device).
基金Project(2011-0027035) supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF)funded by the Ministry of Education,Science and Technology,Korea
文摘To increase the machine accuracy by improving the stiffness of bearings,a preload was applied to bearings.A variable preload technology was necessary to perform machining processes in both low and high speed regions.An automatic variable preload device was fabricated using an eccentric mass.By installing the fabricated device on a spindle,the effect of the automatic variable preload device on the performance of the spindle was analyzed.In the results of the vibration measurement of the spindle,the vibration is increased by 20%-37% according to measurement points at the maximum rotation speed of 5 000 r/min.And,in the results of the noise measurement of the spindle,the spindle rotation speed is increased by about 1.9% and 1.5% at the front and side of the spindle,respectively.Based on the results of this analysis,an improved method that reduces such effects on the performance of the spindle is proposed.
文摘In order to prevent unwanted excited vibrations and to secure better machining precision in large size heavy duty machine tools dynamic stiffness is one of the most desirable and critical properties. In the past decades, many researches on machine tool stiffness test and evaluation methodology have been made. However any methodology for a Pin Turning Device (PTD), which is a special kind of turning lathe for machining big size crankshaft pins, is rarely found among them. This study proposes a test and evaluation process of stiffness of a PTD by measuring frequency response function at the tool center point (TCP). For conformance proving for the proposed methodology, stiffness of a PTD obtained by the proposed method with impact hammer test (IHT) has been compared with that determined by FEM.
文摘An individual's mental health influences their capacity to think effectively,feel emotionally stable,and perform daily activities.As mental health concerns become more prevalent worldwide,new awareness and diagnostic and treatment tactics are needed.Digital tools and technology are helping solve these problems by providing scalable,tailored solutions for large populations.This detailed review examines mental health‐promoting internet tools.Smartphone applications,web‐based therapy systems,wearable tech,artificial intelligence‐powered resources,and virtual reality(VR)technologies were evaluated for efficacy and side effects.PubMed,PsycINFO,Scopus,IEEE Xplore,and Google Scholar were carefully searched.Search terms included“digital mental health tools,”“online therapy,”and“AI in mental health.”Randomized controlled trials,cohort studies,cross‐sectional studies,systematic reviews,and meta‐analyses of digital technology and mental health were included from among the literature published after 2010.Cognitive behavioral therapy methods,mood monitoring,and mindfulness exercises are among the numerous features of smartphone applications that have been demonstrated to mitigate symptoms of anxiety,depression,and tension.Online therapy platforms let marginalized individuals obtain therapy remotely.Wearable technology may detect heart rate,blood pressure,and sleep length,which may reveal mental health difficulties.Chatbots employ machine learning algorithms and natural language processing to deliver customized support and show promise for quick intervention.Exposure therapy for anxiety and trauma is increasingly using virtual reality environments.Although digital mental health therapies face challenges in relation to data privacy,limited long‐term efficacy,and technological inequality,digital technologies are modernizing mental healthcare.By offering inexpensive and effective alternatives to traditional therapies,digital technologies may help healthcare systems meet the growing demand for mental health services and overall well‐being.
