At present, the most common micro/nano-scale fabri ca tion processes include the plane silicon process based on IC technology, stereo silicon process, LIGA, quasi-LIGA based on near ultra violet deep lithography, MEMS...At present, the most common micro/nano-scale fabri ca tion processes include the plane silicon process based on IC technology, stereo silicon process, LIGA, quasi-LIGA based on near ultra violet deep lithography, MEMS, energy beam etching and micro/nano-machining, etc. A common problem for t hese processes is the difficulty to fabricate arbitrary form for 3-dimensional micro/nano-parts, devices or mechanisms. To develop advanced MEMS manufacturin g technology, and to achieve fabrication of true 3-dimensional parts, devices or mechanisms, this paper proposes a nanofabrication technology for rapid proto typing of 3-dimensional parts, using plasma chemical vapor deposition (PCVD). This process can be describes as follows: A laser beam is produced by a low power, quasi molecule laser. It enters the vac uum chamber through a window, and is focused on with the substrate surface. A ga s in the chamber is ionized by the laser beam to produce PCVD on the substrate s urface, and forms a particle of the size of Ф100 nm (its thickness is about 100 nm). When the laser beam moves along X-axis, many particles form a line. Then the laser beam moves one step in Y-axis to form a new line. A plane is complete d by many lines. Then the substrate moves in Z-axis to form new plane. Eventu ally, many planes form a 3-dimensional component. Using available CAD/CAM softw are with this process, rapid prototyping of complex components can be achieved. A nanometer precision linear motor, such as that described in Chinese national p atent (patent No. ZL 98 2 16753.9), can be used to obtain the nanometer precisio n movements in the process. The process does not require mask, can be used for v arious rapid prototyping materials, to obtain high fabrication precision (its sc ale precision is 15 nm), and larger ratio of height to width of micro/nano-stru cture. It can find widespread applications in the fabrication of micro-mechani sm, trimming IC, and fabricating minilens, etc.展开更多
Three dimensional （3D） printing technology was utilized to fabricate a new type of drug implant with complicated architectures, employing levofloxacin （LVFX） and rifampicine （RFP） as model drugs. The prepared dr...Three dimensional （3D） printing technology was utilized to fabricate a new type of drug implant with complicated architectures, employing levofloxacin （LVFX） and rifampicine （RFP） as model drugs. The prepared drug implant prototype consists of a doublelayer structure, of which the upper region is a reservoir system containing RFP and the lower region is a matrix one containing LVFX. The release test in vivo revealed that LVFX was released in the early stage; no RFP was detected until 8th day; both of them continuously released more than 6 weeks. Therefore, 3D printing technology provides a precise and feasible method to fabricate a controlled-releasing drug implant with complicated architectures and this drug implant may present a new strategy for the prophylaxis and treatment of bone diseases such as combined bone infections and bone tuberculosis in the near future.展开更多
Based on Vacuum Differential Pressure Casting (VDPC) precision forming technology and the Selective Laser Sintering (SLS) Rapid Prototyping (RP) technology, a rapid manufacturing method called Rapid Precision Casting ...Based on Vacuum Differential Pressure Casting (VDPC) precision forming technology and the Selective Laser Sintering (SLS) Rapid Prototyping (RP) technology, a rapid manufacturing method called Rapid Precision Casting (RPC) process from computer three-dimensional solid models to metallic parts was investigated. The experimental results showed that the main advantage of RPC was not only its ability to cast higher internal quality and more accurate complex thin-walled aluminum alloy parts, but also the greatly-reduced lead time cycle from Selective Laser Sintering (SLS) plastic prototyping to metallic parts. The key forming technology of RPC for complex thin-walled metallic parts has been developed for new casting production and Rapid Tooling (RT), and it is possible to rapidly manufacture high-quality and accurate metallic parts by means of RP in foundry industry.展开更多
美国定向能机动近程防空(directed energy maneuver-short range air defense,DE M-SHORAD)计划通过击伤、摧毁或压制旋转翼无人机、固定翼无人机以及火箭弹、火炮炮弹、迫击炮弹(rockets,artillery and mortar,RAM)等威胁目标,为机动...美国定向能机动近程防空(directed energy maneuver-short range air defense,DE M-SHORAD)计划通过击伤、摧毁或压制旋转翼无人机、固定翼无人机以及火箭弹、火炮炮弹、迫击炮弹(rockets,artillery and mortar,RAM)等威胁目标,为机动部队提供伴随防空,对抗新兴威胁,属于美国陆军防空反导现代化的优先项目之一。首先介绍了DE M-SHORAD研制计划;其次详细分析了系统结构,并由系统参数评估了系统的作战性能;最后梳理了系统的研制进展。通过综合分析可知,DE M-SHORAD系统采用最佳组件,通过快速原型方法实现激光武器系统在装甲车上的集成;为降低技术风险,该计划在发展方式上分为两个阶段,首先集成、测试2 kW~5 kW机动实验型高能激光器(mobile experimental high-energy laser,MEHEL),然后再研制50 kW级的多任务高能激光器(multi-mission high-energy laser,MMHEL)。经计算可得:MEHEL和MMHEL对无人机的最大射程分别约为0.77 km、4.8 km。展开更多
文摘At present, the most common micro/nano-scale fabri ca tion processes include the plane silicon process based on IC technology, stereo silicon process, LIGA, quasi-LIGA based on near ultra violet deep lithography, MEMS, energy beam etching and micro/nano-machining, etc. A common problem for t hese processes is the difficulty to fabricate arbitrary form for 3-dimensional micro/nano-parts, devices or mechanisms. To develop advanced MEMS manufacturin g technology, and to achieve fabrication of true 3-dimensional parts, devices or mechanisms, this paper proposes a nanofabrication technology for rapid proto typing of 3-dimensional parts, using plasma chemical vapor deposition (PCVD). This process can be describes as follows: A laser beam is produced by a low power, quasi molecule laser. It enters the vac uum chamber through a window, and is focused on with the substrate surface. A ga s in the chamber is ionized by the laser beam to produce PCVD on the substrate s urface, and forms a particle of the size of Ф100 nm (its thickness is about 100 nm). When the laser beam moves along X-axis, many particles form a line. Then the laser beam moves one step in Y-axis to form a new line. A plane is complete d by many lines. Then the substrate moves in Z-axis to form new plane. Eventu ally, many planes form a 3-dimensional component. Using available CAD/CAM softw are with this process, rapid prototyping of complex components can be achieved. A nanometer precision linear motor, such as that described in Chinese national p atent (patent No. ZL 98 2 16753.9), can be used to obtain the nanometer precisio n movements in the process. The process does not require mask, can be used for v arious rapid prototyping materials, to obtain high fabrication precision (its sc ale precision is 15 nm), and larger ratio of height to width of micro/nano-stru cture. It can find widespread applications in the fabrication of micro-mechani sm, trimming IC, and fabricating minilens, etc.
基金Funded by the Graduate Innovation Fund of the Huazhong University of Science and Technology, the "863" Key Project of the National High Technology Research and Development Program of China (No.2006AA02A124)the Program for New Century Excellent Talents in University from the Ministry of Education of China( NCET-05-0647)
文摘Three dimensional （3D） printing technology was utilized to fabricate a new type of drug implant with complicated architectures, employing levofloxacin （LVFX） and rifampicine （RFP） as model drugs. The prepared drug implant prototype consists of a doublelayer structure, of which the upper region is a reservoir system containing RFP and the lower region is a matrix one containing LVFX. The release test in vivo revealed that LVFX was released in the early stage; no RFP was detected until 8th day; both of them continuously released more than 6 weeks. Therefore, 3D printing technology provides a precise and feasible method to fabricate a controlled-releasing drug implant with complicated architectures and this drug implant may present a new strategy for the prophylaxis and treatment of bone diseases such as combined bone infections and bone tuberculosis in the near future.
文摘Based on Vacuum Differential Pressure Casting (VDPC) precision forming technology and the Selective Laser Sintering (SLS) Rapid Prototyping (RP) technology, a rapid manufacturing method called Rapid Precision Casting (RPC) process from computer three-dimensional solid models to metallic parts was investigated. The experimental results showed that the main advantage of RPC was not only its ability to cast higher internal quality and more accurate complex thin-walled aluminum alloy parts, but also the greatly-reduced lead time cycle from Selective Laser Sintering (SLS) plastic prototyping to metallic parts. The key forming technology of RPC for complex thin-walled metallic parts has been developed for new casting production and Rapid Tooling (RT), and it is possible to rapidly manufacture high-quality and accurate metallic parts by means of RP in foundry industry.
