Natural rubber (NR) is widely used in various fields including aerospace, military industry and transportation due to its superior elasticity and comprehensive mechanical properties. Nonetheless, the commercial NR pre...Natural rubber (NR) is widely used in various fields including aerospace, military industry and transportation due to its superior elasticity and comprehensive mechanical properties. Nonetheless, the commercial NR prepared by different methods usually exhibits different mechanical properties, primarily due to variations in processing conditions during the conversion from latex to bulk rubber material. Consequently, this poses challenges in scientific research and industrial production of NR. In order to assess the properties of various commercially available NR and identify key structural and compositional components, this study systematically compares and analyzes four representative NR raw materials: air dried sheet (ADS), ribbed smoked sheets (RSS), constant viscidity NR (CV), and whole field latex rubber (WF). The investigation focuses on evaluating their static mechanical behavior, SIC behavior, wear resistance, and fatigue resistance. The findings indicate that protein and gel content exhibit a crucial influence on the NR properties. These constituents contribute to the formation of a high-crosslinking density region, generating a heterogeneous network structure within the rubber. This structure amplifies strains during deformation, leading to earlier and stronger strain-induced crystallization (SIC). Among the four commercial NR brands, RSS demonstrates superior overall mechanical and dynamic properties owing to its high protein and gel content. This study serves as a valuable reference for comprehending the differences in properties among various commercial NR, thereby offering guidance for the actual processing and selection of NR.展开更多
宏程序是数控系统提供给客户的一种类似于高级语言的编程方式,含有逻辑运算、算术运算和函数等混合功能,通过更改同一程序的参数设置,可实现多种相似工件的精确加工;而梯形螺纹是工程中应用广泛的结合形式,用于传递力和运动。由于螺纹...宏程序是数控系统提供给客户的一种类似于高级语言的编程方式,含有逻辑运算、算术运算和函数等混合功能,通过更改同一程序的参数设置,可实现多种相似工件的精确加工;而梯形螺纹是工程中应用广泛的结合形式,用于传递力和运动。由于螺纹刀牙形角小、刀具强度弱,易引起刀具三刃振动切削而严重影响精度,使得梯形螺纹在传统加工中是一个难点。本文基于FANUC Series Oi mate-TC数控系统,从梯形螺纹加工方法分析、工艺设计和程序编制等方面对梯形螺纹的数控车削方法进行探讨。展开更多
Video is used across a range of applicaticos,from low data-rate mdeo telephony to digitalbroadcast high deftnuzontelevision. Since all applications in thts range require that digually represent-ed sequece of images be...Video is used across a range of applicaticos,from low data-rate mdeo telephony to digitalbroadcast high deftnuzontelevision. Since all applications in thts range require that digually represent-ed sequece of images be reduced in let-rtue for efficient transmision or strage, all applications can uli-lize the same core compression technology. CLI has spent nearl two decades advancing the quality andapplication of digitof video technolegy and continues to rvaluaie meny video compression techniques in-cluding fractof coding, mavelets, subband coding, the discreie cisine transform (DCT), and vectorquantization. CLI currently has concluded that the discrete cosine transform (DCT) combined with mo-tion compensation provides the best pictrue quality for a wide range of video applicarions. In face, theDCT is the technology used by telecommunicationscomputer, and consumer video standards such as H.261 ,JPEG ,adn MPEG. This paper reviews these and other digital video compression iechnologies andthen discusses how CLI applies them to dtfferent video applications. Even within standardsbased mar-kets such as that for MPEG video ditribution syuerns, different products are differentiated easily bydifferences between their proprietary methods for preprocessing ,coding mode selection, postprocessing,etc.展开更多
基金supported by Research and Development Program in key area of Guangdong Province(No.2020B020217001)the National Natural Science Foundation of China(No.52173058)National Key R&D Program of China(No.2022YFD2301202).
文摘Natural rubber (NR) is widely used in various fields including aerospace, military industry and transportation due to its superior elasticity and comprehensive mechanical properties. Nonetheless, the commercial NR prepared by different methods usually exhibits different mechanical properties, primarily due to variations in processing conditions during the conversion from latex to bulk rubber material. Consequently, this poses challenges in scientific research and industrial production of NR. In order to assess the properties of various commercially available NR and identify key structural and compositional components, this study systematically compares and analyzes four representative NR raw materials: air dried sheet (ADS), ribbed smoked sheets (RSS), constant viscidity NR (CV), and whole field latex rubber (WF). The investigation focuses on evaluating their static mechanical behavior, SIC behavior, wear resistance, and fatigue resistance. The findings indicate that protein and gel content exhibit a crucial influence on the NR properties. These constituents contribute to the formation of a high-crosslinking density region, generating a heterogeneous network structure within the rubber. This structure amplifies strains during deformation, leading to earlier and stronger strain-induced crystallization (SIC). Among the four commercial NR brands, RSS demonstrates superior overall mechanical and dynamic properties owing to its high protein and gel content. This study serves as a valuable reference for comprehending the differences in properties among various commercial NR, thereby offering guidance for the actual processing and selection of NR.
文摘宏程序是数控系统提供给客户的一种类似于高级语言的编程方式,含有逻辑运算、算术运算和函数等混合功能,通过更改同一程序的参数设置,可实现多种相似工件的精确加工;而梯形螺纹是工程中应用广泛的结合形式,用于传递力和运动。由于螺纹刀牙形角小、刀具强度弱,易引起刀具三刃振动切削而严重影响精度,使得梯形螺纹在传统加工中是一个难点。本文基于FANUC Series Oi mate-TC数控系统,从梯形螺纹加工方法分析、工艺设计和程序编制等方面对梯形螺纹的数控车削方法进行探讨。
文摘Video is used across a range of applicaticos,from low data-rate mdeo telephony to digitalbroadcast high deftnuzontelevision. Since all applications in thts range require that digually represent-ed sequece of images be reduced in let-rtue for efficient transmision or strage, all applications can uli-lize the same core compression technology. CLI has spent nearl two decades advancing the quality andapplication of digitof video technolegy and continues to rvaluaie meny video compression techniques in-cluding fractof coding, mavelets, subband coding, the discreie cisine transform (DCT), and vectorquantization. CLI currently has concluded that the discrete cosine transform (DCT) combined with mo-tion compensation provides the best pictrue quality for a wide range of video applicarions. In face, theDCT is the technology used by telecommunicationscomputer, and consumer video standards such as H.261 ,JPEG ,adn MPEG. This paper reviews these and other digital video compression iechnologies andthen discusses how CLI applies them to dtfferent video applications. Even within standardsbased mar-kets such as that for MPEG video ditribution syuerns, different products are differentiated easily bydifferences between their proprietary methods for preprocessing ,coding mode selection, postprocessing,etc.
