Nowadays, nano-technology is a promising option for scientists to enhance dental conditions and provide new techniques to offer a more reliable and comfortable therapeutic pickups. In this regard, there are different ...Nowadays, nano-technology is a promising option for scientists to enhance dental conditions and provide new techniques to offer a more reliable and comfortable therapeutic pickups. In this regard, there are different methods to manufacture novel nano-structured dental materials, and also modern drug delivery techniques. In this review article, all our efforts are based on the recently nano-dental approaches closely linked to treat or prevent some common dental diseases including tooth erosion, tooth sensitivity, periodontal disease, oral cancer, and so on. All the data and articles putted in this survey are gathered from Google Scholar, PubMed, and some dental databases.展开更多
The kind of micro-/nano-meter precision actuator in cludes a piezoelectric one, an electric deformation one, a magnetic deformation one, a mechanical one, and a mechanical and electrical one. This paper puts forw ard ...The kind of micro-/nano-meter precision actuator in cludes a piezoelectric one, an electric deformation one, a magnetic deformation one, a mechanical one, and a mechanical and electrical one. This paper puts forw ard a mechanical and electrical step actuator of nanometer precision, which cons ists of a step motor of large fine-dividing number of step angle, shaft couplin gs, a decelerator of large decelerating ratio, a screw mechanism and a pole of U shape, and has the minimum step displacement of 10 nm, the step displac ement precision of 1 nm, the step frequency of 4 kHz, the maximum loadability of 20 kg. In order to achieve the nano displacement of nano precision by this actu ator, the theoretical analysis of stress and strain must be made on the transmit ting course of nano displacement of the actuator, and their numerical simulation is done by computer. The paper establishes the constitutive equation of 3-D stress and the strain co ordinate equation of the composing system of the nanometer precision actuator. A s a result, the theoretical relation among stress and strain and displacement is set up. The torque of the step motor produces a thrust to transmit the displace ment of the above system of the parts and assemblies to output the needed nano d isplacement. In the case of concrete analysis and calculating, the comparing met hod of film-roof is applied to analyze and calculate the motor axis, decelerato r axes, the screw pole and the nut. The analysis method of plane stress and stra in is used to analyze and calculate the shaft couplings and gears. The analysis method of beam stress and strain is used to do the pole of U shape. These calcul ation is belong to the physical non-linear problem. Under the condition of smal l deformation, the analysis way of the finite element can be combined with the a bove analyses and calculations. The elementary analysis results show that the na nometer precision actuator can be applied in STM nanofabrication.展开更多
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 dimension free curves find wide applications in engineering. There is no problem to express them exactly mathematically, but th e reportage has not been done on the investigation of precision analysis of thre e-...Three dimension free curves find wide applications in engineering. There is no problem to express them exactly mathematically, but th e reportage has not been done on the investigation of precision analysis of thre e-dimension free curves nanofabrication. Nanofabrication Precision includes the geometrical precision and the precision of driving system (below simply cal led the system precision). This paper submits the precision analysis method of c urve normal vector to analyze geometrical precision. Take an aspherical surf ace for example, it can be fitted and constructed by tensor product parameter cu rves, such as linear drawing curves, straight veins curves, rotating curves, swe eping curves, DUCT curves and Geomap curves. Then the curves of the aspherical s urface is iterated and modified to select the best fitted curves of the aspheric al surface. Finally, the geometrical precision of perfect approximate aspherical surface fitting has been sought. This kind of geometrical fitting construction is very important. Another is the system precision, which contains axial position precision, line p recision, and twisting and swinging precision, etc. The paper adopts the theory of precision optimum match (Prof. Wang Er-qi first put forward in 19 83) to allocate precision optimumly. The minimum cost is used as an objective fu nction, and weight method matches the precision. To obtain the optimum match combination of the minimum cost design parameters and every composing element t olerance, the precision is iterated and sought optimumly to design the system op timumly. The theoretical analysis shows that it’s feasible to control three dim ension free curves nanofabrication within nanometer scale precision.展开更多
Hydration cracks of magnesia-spinel bricks in cement industry have been serious problems for both refractory producers and refractory users for a long time.When magnesia-spinel bricks are kept for more than 6months,th...Hydration cracks of magnesia-spinel bricks in cement industry have been serious problems for both refractory producers and refractory users for a long time.When magnesia-spinel bricks are kept for more than 6months,the bricks tend to have reaction with water or moisture and result in cracks and loss on their structural strength. Those bricks cannot be used anymore and cause substantial loss for the related parties. In 2013,the Siam Refractory Industry Co.,Ltd.,Thailand,successfully developed and applied a special nano-technology to create ＂Anti-Hydration Magnesia-Spinel Bricks ＂ for cement industry which can have the storage time more than two years even in high humidity areas. The cement producers can ensure that all bricks still have good properties as the new ones.展开更多
The surface quality of the substrate is a crucial factor in building ＂clean＂ quantum-dimensional systems. There are a number of micro-nano metric methods for the analysis state of surface： the atomic force microsco...The surface quality of the substrate is a crucial factor in building ＂clean＂ quantum-dimensional systems. There are a number of micro-nano metric methods for the analysis state of surface： the atomic force microscopy, the scanning tunneling microscopy and others. The SE （surface electron） over substrate has a ＂soft＂ hydrogen-like spectrum in the normal direction and the SEs mobility along is sensitive to the inhomogeneities of the substrate and this is analyzed in work. The values of electron mobility and energy of thermal activation are basic parameters of transport process which essentially depend on the helium film thickness. For analysis of nano-size inhomogeneities of substrate here we apply a new method providing a uniformity of the film thickness on substrate and fixing of measuring cell with supply wires. The plunger with electro-mechanic driver into a hermetic chamber is used for variation the helium level and consequently the film thickness. Considering values the conductivity and the variation of potential along surface is estimated the effective size of roughness from several nanometers （for non-saturated helium film） to 10^2 nm （for saturated film）.展开更多
文摘Nowadays, nano-technology is a promising option for scientists to enhance dental conditions and provide new techniques to offer a more reliable and comfortable therapeutic pickups. In this regard, there are different methods to manufacture novel nano-structured dental materials, and also modern drug delivery techniques. In this review article, all our efforts are based on the recently nano-dental approaches closely linked to treat or prevent some common dental diseases including tooth erosion, tooth sensitivity, periodontal disease, oral cancer, and so on. All the data and articles putted in this survey are gathered from Google Scholar, PubMed, and some dental databases.
文摘The kind of micro-/nano-meter precision actuator in cludes a piezoelectric one, an electric deformation one, a magnetic deformation one, a mechanical one, and a mechanical and electrical one. This paper puts forw ard a mechanical and electrical step actuator of nanometer precision, which cons ists of a step motor of large fine-dividing number of step angle, shaft couplin gs, a decelerator of large decelerating ratio, a screw mechanism and a pole of U shape, and has the minimum step displacement of 10 nm, the step displac ement precision of 1 nm, the step frequency of 4 kHz, the maximum loadability of 20 kg. In order to achieve the nano displacement of nano precision by this actu ator, the theoretical analysis of stress and strain must be made on the transmit ting course of nano displacement of the actuator, and their numerical simulation is done by computer. The paper establishes the constitutive equation of 3-D stress and the strain co ordinate equation of the composing system of the nanometer precision actuator. A s a result, the theoretical relation among stress and strain and displacement is set up. The torque of the step motor produces a thrust to transmit the displace ment of the above system of the parts and assemblies to output the needed nano d isplacement. In the case of concrete analysis and calculating, the comparing met hod of film-roof is applied to analyze and calculate the motor axis, decelerato r axes, the screw pole and the nut. The analysis method of plane stress and stra in is used to analyze and calculate the shaft couplings and gears. The analysis method of beam stress and strain is used to do the pole of U shape. These calcul ation is belong to the physical non-linear problem. Under the condition of smal l deformation, the analysis way of the finite element can be combined with the a bove analyses and calculations. The elementary analysis results show that the na nometer precision actuator can be applied in STM nanofabrication.
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.
文摘Three dimension free curves find wide applications in engineering. There is no problem to express them exactly mathematically, but th e reportage has not been done on the investigation of precision analysis of thre e-dimension free curves nanofabrication. Nanofabrication Precision includes the geometrical precision and the precision of driving system (below simply cal led the system precision). This paper submits the precision analysis method of c urve normal vector to analyze geometrical precision. Take an aspherical surf ace for example, it can be fitted and constructed by tensor product parameter cu rves, such as linear drawing curves, straight veins curves, rotating curves, swe eping curves, DUCT curves and Geomap curves. Then the curves of the aspherical s urface is iterated and modified to select the best fitted curves of the aspheric al surface. Finally, the geometrical precision of perfect approximate aspherical surface fitting has been sought. This kind of geometrical fitting construction is very important. Another is the system precision, which contains axial position precision, line p recision, and twisting and swinging precision, etc. The paper adopts the theory of precision optimum match (Prof. Wang Er-qi first put forward in 19 83) to allocate precision optimumly. The minimum cost is used as an objective fu nction, and weight method matches the precision. To obtain the optimum match combination of the minimum cost design parameters and every composing element t olerance, the precision is iterated and sought optimumly to design the system op timumly. The theoretical analysis shows that it’s feasible to control three dim ension free curves nanofabrication within nanometer scale precision.
文摘Hydration cracks of magnesia-spinel bricks in cement industry have been serious problems for both refractory producers and refractory users for a long time.When magnesia-spinel bricks are kept for more than 6months,the bricks tend to have reaction with water or moisture and result in cracks and loss on their structural strength. Those bricks cannot be used anymore and cause substantial loss for the related parties. In 2013,the Siam Refractory Industry Co.,Ltd.,Thailand,successfully developed and applied a special nano-technology to create ＂Anti-Hydration Magnesia-Spinel Bricks ＂ for cement industry which can have the storage time more than two years even in high humidity areas. The cement producers can ensure that all bricks still have good properties as the new ones.
文摘The surface quality of the substrate is a crucial factor in building ＂clean＂ quantum-dimensional systems. There are a number of micro-nano metric methods for the analysis state of surface： the atomic force microscopy, the scanning tunneling microscopy and others. The SE （surface electron） over substrate has a ＂soft＂ hydrogen-like spectrum in the normal direction and the SEs mobility along is sensitive to the inhomogeneities of the substrate and this is analyzed in work. The values of electron mobility and energy of thermal activation are basic parameters of transport process which essentially depend on the helium film thickness. For analysis of nano-size inhomogeneities of substrate here we apply a new method providing a uniformity of the film thickness on substrate and fixing of measuring cell with supply wires. The plunger with electro-mechanic driver into a hermetic chamber is used for variation the helium level and consequently the film thickness. Considering values the conductivity and the variation of potential along surface is estimated the effective size of roughness from several nanometers （for non-saturated helium film） to 10^2 nm （for saturated film）.
