Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and effic...Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.展开更多
研究表明血管钙化是一个类似成骨的主动、可预防和可逆转的高度可调控的生物学过程。骨形态发生蛋白(bone morphogenetic proteins,BMPs)家族作为转化生长因子β(transforming growth f a c t o r-β,TG F-β)超家族的成员,因具有诱导...研究表明血管钙化是一个类似成骨的主动、可预防和可逆转的高度可调控的生物学过程。骨形态发生蛋白(bone morphogenetic proteins,BMPs)家族作为转化生长因子β(transforming growth f a c t o r-β,TG F-β)超家族的成员,因具有诱导骨形成的特点而得名,到目前为止,已发现3 0余种BMP成员,其中BMP-2是一类唯一能够单独诱导骨组织形成的局部生长因子。目前有关动脉粥样硬化及血管钙化中BMP-2作用机制的研究日益增多。本文就近年BMP-2诱导动脉钙化(arterial calcification,AC)的相关研究进展作一综述。展开更多
To satisfy the measuring demands for the micro components of the industry, micro/nano probing systems with various ball tips have been developed. However, most of them cannot be used to measure the real micro geometri...To satisfy the measuring demands for the micro components of the industry, micro/nano probing systems with various ball tips have been developed. However, most of them cannot be used to measure the real micro geometrical features high precisely because the parameters of the ball tips are not appropriate. The ball tips with a diameter of less than 100 μm, a sphericity and eccentricity of far less than 1 μm are required urgently. A review on the state-of-the-art of ball tips of micro/nano probing systems is presented. The material characteristics and geometric parameters of now available ball tips are introduced sepa- rately. The existing fabrication methods for the ball tips are demonstrated and summarized. The ball tips＇ future trends, which are smaller diameter, better sphericity and smaller eccentricity, are proposed in view of the practical requirements of high-precision measurement for micro geometrical features. Some challenges have to be faced in future, such as the promotion and high-precision measurement for the small ball tip＇s sphericity and eccentricity. Fusion method without the gravity effect when the molten ball tip solidifying is a more suitable way to fabricate a small diameter ball tip together with a shaft.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51305322,51405364,51475348)
文摘Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.
文摘研究表明血管钙化是一个类似成骨的主动、可预防和可逆转的高度可调控的生物学过程。骨形态发生蛋白(bone morphogenetic proteins,BMPs)家族作为转化生长因子β(transforming growth f a c t o r-β,TG F-β)超家族的成员,因具有诱导骨形成的特点而得名,到目前为止,已发现3 0余种BMP成员,其中BMP-2是一类唯一能够单独诱导骨组织形成的局部生长因子。目前有关动脉粥样硬化及血管钙化中BMP-2作用机制的研究日益增多。本文就近年BMP-2诱导动脉钙化(arterial calcification,AC)的相关研究进展作一综述。
基金Supported by National Natural Science Foundation of China(Grant Nos.51675157,51475131)State Key Laboratory of Precision Measuring Technology and Instruments of China(Grant No.PIL1401)
文摘To satisfy the measuring demands for the micro components of the industry, micro/nano probing systems with various ball tips have been developed. However, most of them cannot be used to measure the real micro geometrical features high precisely because the parameters of the ball tips are not appropriate. The ball tips with a diameter of less than 100 μm, a sphericity and eccentricity of far less than 1 μm are required urgently. A review on the state-of-the-art of ball tips of micro/nano probing systems is presented. The material characteristics and geometric parameters of now available ball tips are introduced sepa- rately. The existing fabrication methods for the ball tips are demonstrated and summarized. The ball tips＇ future trends, which are smaller diameter, better sphericity and smaller eccentricity, are proposed in view of the practical requirements of high-precision measurement for micro geometrical features. Some challenges have to be faced in future, such as the promotion and high-precision measurement for the small ball tip＇s sphericity and eccentricity. Fusion method without the gravity effect when the molten ball tip solidifying is a more suitable way to fabricate a small diameter ball tip together with a shaft.
