137 Cs is an artificial radionuclide with a half-life of 30.2 years,which was released into the environment as a byproduct of atmospheric testing of nuclear weapons during the period of 1950s to 1970s with a peak depo...137 Cs is an artificial radionuclide with a half-life of 30.2 years,which was released into the environment as a byproduct of atmospheric testing of nuclear weapons during the period of 1950s to 1970s with a peak deposition in 1963.137 Cs fallout was strongly and rapidly adsorbed by soil particles when it deposited on the ground mostly with precipitation.Its following movements will associate with the adsorbed particles.137 Cs tracing technique has been widely used in soil erosion and sedimentation studies since 1980s.This paper introduces the basis of the technique and shows several case studies of assessment of soil erosion rates,investigation of sediment sources and dating of reservoir deposits by using the technique in the Loess Plateau and the Upper Yangtze River Basin.展开更多
Compared with bar code and quick response( QR) code in the storage and retailing management of textiles, the ultra-high frequency( UHF) radio frequency identification( RFID) tags have high information capacity as well...Compared with bar code and quick response( QR) code in the storage and retailing management of textiles, the ultra-high frequency( UHF) radio frequency identification( RFID) tags have high information capacity as well as reliability in complex environmental conditions. In this study,the UHF RFID tags with perfect integration with textiles are assembled with screen-printed antenna on woven water-mark nylon fabric and Alien UHF integrated circuit( IC), and their reading performance under various washing and bending conditions is evaluated by an RFID reader. The results show that the tags after fifty bending( both arch and sink) cycles of screen-printed antenna still have reading distance more than 5.5 m,and an average reading distance is over 4.0 m after five washing cycles. The experimental results demonstrate that the tag antenna on the water-mark fabric can be manufactured by the screen-printing technology,and a coating process on this fabric facilitates the reading performance and the resistance against complex mechanical impact.展开更多
Three-dimensional (3D) printing is a novel promising technology based on 3D imaging and layer-by-layer additive fabrication. It has a profound influence on all aspects of our lives and is playing an increasing impor...Three-dimensional (3D) printing is a novel promising technology based on 3D imaging and layer-by-layer additive fabrication. It has a profound influence on all aspects of our lives and is playing an increasing important role in many areas including engineering, manufacturing, art, education and medicine. "3D bioprinting" has been put forward with the technical progress in 3D printing and might be a possible way to solve the serious problem of human organ shortage in tissue engineering and regenerative medicine. Many research groups flung them into this area and have already made some gratifying achievements. However, it is a long way to fabricate a live organ. Many elements lead to the limitation of 3D bioprinting. This review introduces the background and development history of 3D bioprinting, compares different approaches of 3D bioprinting and illustrates the key factors of the printing process. Meanwhile, this review also points out existing challenges of 3D bioprinting and has a great prospect. Some points proposed in this review might be served as reference for the research of this field.展开更多
Nanoclay-enabled self-supporting printing has been emerging as a promising filament-based extrusion fabrication approach for different biomedical and engineering applications including tissue engineering. With the add...Nanoclay-enabled self-supporting printing has been emerging as a promising filament-based extrusion fabrication approach for different biomedical and engineering applications including tissue engineering. With the addition of nanoclay powders, liquid build materials may exhibit solid-like behavior upon extrusion and can be directly printed in air into complex three-dimensional structures. The objective of this study is to investigate the effect of nanoclay on the extrudability of N-isopropylacrylamide (NIPAAm) and the effect of standoff distance on the print quality during nanoclay-enabled direct printing. It is found that the addition of nanoclay can significantly improve the NIPAAm extrudability and effectively eliminate die swelling in material extrusion. In addition, with the increase of standoff distance, deposited filaments change from over-deposited to well-defined to stretched to broken, the filament width decreases, and the print fidelity deteriorates. A mathematical model is further proposed to determine the optimal standoff distance to achieve better print fidelity during nanoclay-enabled direct printing. Based on the extrudability and standoff distance knowledge from this study, NIPAAm-Laponite nanoclay and NIPAAm-Laponite nanoclay-graphene oxide nanocomposite hydrogel precursors are successfully printed into a three-layered one-dimensional responsive pattern, demonstrating the good extrudability and print quality during nanoclay-enabled printing under optimal printing conditions.展开更多
In order to build a ceramic component by inkjet printing, the object must be fabricated through the interaction and solidification of drops, typically in the range of 10–100 p L. In order to achieve this goal, stable...In order to build a ceramic component by inkjet printing, the object must be fabricated through the interaction and solidification of drops, typically in the range of 10–100 p L. In order to achieve this goal, stable ceramic inks must be developed. These inks should satisfy specific rheological conditions that can be illustrated within a parameter space defined by the Reynolds and Weber numbers. Printed drops initially deform on impact with a surface by dynamic dissipative processes, but then spread to an equilibrium shape defined by capillarity. We can identify the processes by which these drops interact to form linear features during printing, but there is a poorer level of understanding as to how 2D and 3D structures form. The stability of 2D sheets of ink appears to be possible over a more limited range of process conditions that is seen with the formation of lines. In most cases, the ink solidifies through evaporation and there is a need to control the drying process to eliminate the "coffee ring" defect. Despite these uncertainties, there have been a large number of reports on the successful use of inkjet printing for the manufacture of small ceramic components from a number of different ceramics. This technique offers good prospects as a future manufacturing technique. This review identifies potential areas for future research to improve our understanding of this manufacturing method.展开更多
The CuO-doped ZnO thick films were prepared by the screen printing technique. The CuO doped ZnO composite materials were obtained by mixing AR grade (99.9% pure) Zinc Oxide powder mechanochemically in acetone medium...The CuO-doped ZnO thick films were prepared by the screen printing technique. The CuO doped ZnO composite materials were obtained by mixing AR grade (99.9% pure) Zinc Oxide powder mechanochemically in acetone medium with various weight percentages of Copper Chloride (CulCI2.2H20) powder (1, 3, 5, 7 and 9wt.%). The prepared materials were sintered at 1,000 ℃ for 12 h in air ambience and ball milled to ensure sufficiently fine particle size. The films were characterized by different techniques with respect to their surface morphology and compositional property by means of SEM (scanning electron microscope) and EDXA (energy dispersive x-ray analysis). The surface morphology of the films was studied by SEM and it shows the films are porous in nature and petal-shaped grains of sizes varies from 220 nm to 250 nm were observed. The final composition of each film was determined by the EDXA analysis. The gas response of undoped ZnO and CuO doped ZnO films was studied for different gases such as CO, C12, NH3, Ethanol, H2S and LPG at operating temperature ranging from 50 ℃ to 400 ℃. The 7wt.% CuO-doped ZnO film shows good response to H2S gas (100 ppm) at 250 ℃.展开更多
Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly(dimethylsiloxane) (PDMS) s...Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly(dimethylsiloxane) (PDMS) stamps with relief structures have been widely used to transfer patterns. The traditional fabrication approach of PDMS stamps is time-consuming since the master has been occupied during the curing process. By adding and repeating fast nanoimprint step, many intermediate polymeric molds can be produced from the master and these molds can then be employed to replicate more PDMS stamps while the time used is close to that of the common way. We demonstrated this idea by three masters which were made by the DEM (Deepetching, Electroforming and Microreplicating) and FIB (Focused Ion Beam) techniques. The photos show that the patterns on the PMDS stamps successfully duplicated patterns on the origin masters.展开更多
A novel nano-scale alignment technique based on Moiré signal for room-temperature imprint lithography in the submicron realm is proposed. The Moiré signals generated by a pair of quadruple gratings on two te...A novel nano-scale alignment technique based on Moiré signal for room-temperature imprint lithography in the submicron realm is proposed. The Moiré signals generated by a pair of quadruple gratings on two templates respectively are optically projected onto a photodetector array, then the detected Moiré signals are used to estimate the alignment errors in x and y directions. The experiment result indicates that complex differential Moiré signal is sensitive to relative displacement of the pair of marks than each single Moiré signal, and the alignment resolutions obtained in x and y directions are ±20nm(3σ) and ±24nm(3σ). They can meet the requirement of alignment accuracy for submicron imprint lithography.展开更多
Three-dimensional(3D) printing(3DP) is a rapid prototyping technology that has gained increasing recognition in many different fields. Inherent accuracy and low-cost property enable applicability of 3DP in many areas,...Three-dimensional(3D) printing(3DP) is a rapid prototyping technology that has gained increasing recognition in many different fields. Inherent accuracy and low-cost property enable applicability of 3DP in many areas, such as manufacturing, aerospace,medical, and industrial design. Recently, 3DP has gained considerable attention in the medical field. The image data can be quickly turned into physical objects by using 3DP technology. These objects are being used across a variety of surgical specialties. The shortage of cadaver specimens is a major problem in medical education. However, this concern has been solved with the emergence of 3DP model. Custom-made items can be produced by using 3DP technology. This innovation allows 3DP use in preoperative planning and surgical training. Learning is difficult among medical students because of the complex anatomical structures of the liver. Thus, 3D visualization is a useful tool in anatomy teaching and hepatic surgical training. However,conventional models do not capture haptic qualities. 3DP can produce highly accurate and complex physical models. Many types of human or animal differentiated cells can be printed successfully with the development of 3D bio-printing technology. This progress represents a valuable breakthrough that exhibits many potential uses, such as research on drug metabolism or liver disease mechanism. This technology can also be used to solve shortage of organs for transplant in the future.展开更多
This paper presents a discussion of the characters and design patterns of the digital texture design in fashion fabrics. It starts from the characters of fabric texture design, taking digital printing technology as a ...This paper presents a discussion of the characters and design patterns of the digital texture design in fashion fabrics. It starts from the characters of fabric texture design, taking digital printing technology as a detailed example, and raises a possible design route and pattern of the innovative design of fashion fabrics under digital technology.展开更多
To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bott...To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bottom surface and wafer top surface. In nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relation between the residual re- sist thickness and the pressing force during pressing the mould toward the resist-coated wafer. Based on these analytical studies, a new imprint process, which includes a pre-cure release of the pressing force, was proposed for the high-conformity transfer of nano-patterns from the mould to the wafer. The results of a series of imprint experiments showed that the proposed loading process could meet the requirements for the imprint of different patterns and feature sizes while maintaining a uniform residual resist and non-distorted transfer of nano-patterns from the mould to the resist- coated wafer.展开更多
The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem: the generation of vast amounts of electronic waste, or e-waste throug...The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem: the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions (or bioacid constituents). The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.展开更多
Abstract: The search for "new materials" to manufacture building elements for economical housing is the aim of this work. These materials are the following recycled plastics: Low-density polyethylene (LDPE), rec...Abstract: The search for "new materials" to manufacture building elements for economical housing is the aim of this work. These materials are the following recycled plastics: Low-density polyethylene (LDPE), recycled out of discarded soft drink packs: Polyethylene-terephthalate (PET), recycled out of discarded soft drink bottles; and several plastics, from the printed films used like packages of candies (remainder of production plant by faults in the thickness of the films or in the inked process of themt. These conveniently grounded plastics were taken as "arids" to be mixed with Normal Portland cement, replacing heavy sand and gravel habitually used in these mixtures. These materials are used in constructive elements such as bricks, blocks and plates for economical houses closures or traditional construction. The developed constructive elements offer high thermal insulation, so they can be used in closures with a smaller thickness than conventional bricks and blocks. Besides, they have a lower specific weight than these traditiunal constructive elements. Recycling means lowering costs, making part of the environment contaminating waste useful and providing the unemployed and/or unqualified work force with jobs through uncomplicated technologies. Therefore, this recycling technology has an economic as well as an ecological purpose.展开更多
Three-dimensional(3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and...Three-dimensional(3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing.展开更多
基金supported by National Natural Science Foundation of China (Grant No. 40971169,41101259)Ministry of Environmental Protectionof China (Grant No. 2009ZX07104-002-06)State Key Laboratory of Environmental Geochemistry (Grant No. SKLEG9008)
文摘137 Cs is an artificial radionuclide with a half-life of 30.2 years,which was released into the environment as a byproduct of atmospheric testing of nuclear weapons during the period of 1950s to 1970s with a peak deposition in 1963.137 Cs fallout was strongly and rapidly adsorbed by soil particles when it deposited on the ground mostly with precipitation.Its following movements will associate with the adsorbed particles.137 Cs tracing technique has been widely used in soil erosion and sedimentation studies since 1980s.This paper introduces the basis of the technique and shows several case studies of assessment of soil erosion rates,investigation of sediment sources and dating of reservoir deposits by using the technique in the Loess Plateau and the Upper Yangtze River Basin.
基金National Natural Science Foundation of China(Nos.51405079)China Postdoctoral Science Foundation of China(No.2015M570307)+1 种基金the Fundamental Research Funds for the Central Universities,Chinathe Jiangsu Planned Projects for Postdoctoral Research Funds,China
文摘Compared with bar code and quick response( QR) code in the storage and retailing management of textiles, the ultra-high frequency( UHF) radio frequency identification( RFID) tags have high information capacity as well as reliability in complex environmental conditions. In this study,the UHF RFID tags with perfect integration with textiles are assembled with screen-printed antenna on woven water-mark nylon fabric and Alien UHF integrated circuit( IC), and their reading performance under various washing and bending conditions is evaluated by an RFID reader. The results show that the tags after fifty bending( both arch and sink) cycles of screen-printed antenna still have reading distance more than 5.5 m,and an average reading distance is over 4.0 m after five washing cycles. The experimental results demonstrate that the tag antenna on the water-mark fabric can be manufactured by the screen-printing technology,and a coating process on this fabric facilitates the reading performance and the resistance against complex mechanical impact.
基金Acknowledgements The authors would like to acknowledge the support from National Natural Science Foundation of China under Grant 81501607 and 51475419, Natural Science Foundation of Zhejiang Province of China under Grant LY15H160019, Key Research and Development Projects of Zhejiang Province under Grant 2017C 1054.
文摘Three-dimensional (3D) printing is a novel promising technology based on 3D imaging and layer-by-layer additive fabrication. It has a profound influence on all aspects of our lives and is playing an increasing important role in many areas including engineering, manufacturing, art, education and medicine. "3D bioprinting" has been put forward with the technical progress in 3D printing and might be a possible way to solve the serious problem of human organ shortage in tissue engineering and regenerative medicine. Many research groups flung them into this area and have already made some gratifying achievements. However, it is a long way to fabricate a live organ. Many elements lead to the limitation of 3D bioprinting. This review introduces the background and development history of 3D bioprinting, compares different approaches of 3D bioprinting and illustrates the key factors of the printing process. Meanwhile, this review also points out existing challenges of 3D bioprinting and has a great prospect. Some points proposed in this review might be served as reference for the research of this field.
基金This study was partially supported by the U.S. National Science Foundation (NSF CMMI-1634755).
文摘Nanoclay-enabled self-supporting printing has been emerging as a promising filament-based extrusion fabrication approach for different biomedical and engineering applications including tissue engineering. With the addition of nanoclay powders, liquid build materials may exhibit solid-like behavior upon extrusion and can be directly printed in air into complex three-dimensional structures. The objective of this study is to investigate the effect of nanoclay on the extrudability of N-isopropylacrylamide (NIPAAm) and the effect of standoff distance on the print quality during nanoclay-enabled direct printing. It is found that the addition of nanoclay can significantly improve the NIPAAm extrudability and effectively eliminate die swelling in material extrusion. In addition, with the increase of standoff distance, deposited filaments change from over-deposited to well-defined to stretched to broken, the filament width decreases, and the print fidelity deteriorates. A mathematical model is further proposed to determine the optimal standoff distance to achieve better print fidelity during nanoclay-enabled direct printing. Based on the extrudability and standoff distance knowledge from this study, NIPAAm-Laponite nanoclay and NIPAAm-Laponite nanoclay-graphene oxide nanocomposite hydrogel precursors are successfully printed into a three-layered one-dimensional responsive pattern, demonstrating the good extrudability and print quality during nanoclay-enabled printing under optimal printing conditions.
文摘In order to build a ceramic component by inkjet printing, the object must be fabricated through the interaction and solidification of drops, typically in the range of 10–100 p L. In order to achieve this goal, stable ceramic inks must be developed. These inks should satisfy specific rheological conditions that can be illustrated within a parameter space defined by the Reynolds and Weber numbers. Printed drops initially deform on impact with a surface by dynamic dissipative processes, but then spread to an equilibrium shape defined by capillarity. We can identify the processes by which these drops interact to form linear features during printing, but there is a poorer level of understanding as to how 2D and 3D structures form. The stability of 2D sheets of ink appears to be possible over a more limited range of process conditions that is seen with the formation of lines. In most cases, the ink solidifies through evaporation and there is a need to control the drying process to eliminate the "coffee ring" defect. Despite these uncertainties, there have been a large number of reports on the successful use of inkjet printing for the manufacture of small ceramic components from a number of different ceramics. This technique offers good prospects as a future manufacturing technique. This review identifies potential areas for future research to improve our understanding of this manufacturing method.
文摘The CuO-doped ZnO thick films were prepared by the screen printing technique. The CuO doped ZnO composite materials were obtained by mixing AR grade (99.9% pure) Zinc Oxide powder mechanochemically in acetone medium with various weight percentages of Copper Chloride (CulCI2.2H20) powder (1, 3, 5, 7 and 9wt.%). The prepared materials were sintered at 1,000 ℃ for 12 h in air ambience and ball milled to ensure sufficiently fine particle size. The films were characterized by different techniques with respect to their surface morphology and compositional property by means of SEM (scanning electron microscope) and EDXA (energy dispersive x-ray analysis). The surface morphology of the films was studied by SEM and it shows the films are porous in nature and petal-shaped grains of sizes varies from 220 nm to 250 nm were observed. The final composition of each film was determined by the EDXA analysis. The gas response of undoped ZnO and CuO doped ZnO films was studied for different gases such as CO, C12, NH3, Ethanol, H2S and LPG at operating temperature ranging from 50 ℃ to 400 ℃. The 7wt.% CuO-doped ZnO film shows good response to H2S gas (100 ppm) at 250 ℃.
文摘Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly(dimethylsiloxane) (PDMS) stamps with relief structures have been widely used to transfer patterns. The traditional fabrication approach of PDMS stamps is time-consuming since the master has been occupied during the curing process. By adding and repeating fast nanoimprint step, many intermediate polymeric molds can be produced from the master and these molds can then be employed to replicate more PDMS stamps while the time used is close to that of the common way. We demonstrated this idea by three masters which were made by the DEM (Deepetching, Electroforming and Microreplicating) and FIB (Focused Ion Beam) techniques. The photos show that the patterns on the PMDS stamps successfully duplicated patterns on the origin masters.
文摘A novel nano-scale alignment technique based on Moiré signal for room-temperature imprint lithography in the submicron realm is proposed. The Moiré signals generated by a pair of quadruple gratings on two templates respectively are optically projected onto a photodetector array, then the detected Moiré signals are used to estimate the alignment errors in x and y directions. The experiment result indicates that complex differential Moiré signal is sensitive to relative displacement of the pair of marks than each single Moiré signal, and the alignment resolutions obtained in x and y directions are ±20nm(3σ) and ±24nm(3σ). They can meet the requirement of alignment accuracy for submicron imprint lithography.
基金supported by a grant from the National HighTech Research and Development Projects (Grant No. 2015AA020303)
文摘Three-dimensional(3D) printing(3DP) is a rapid prototyping technology that has gained increasing recognition in many different fields. Inherent accuracy and low-cost property enable applicability of 3DP in many areas, such as manufacturing, aerospace,medical, and industrial design. Recently, 3DP has gained considerable attention in the medical field. The image data can be quickly turned into physical objects by using 3DP technology. These objects are being used across a variety of surgical specialties. The shortage of cadaver specimens is a major problem in medical education. However, this concern has been solved with the emergence of 3DP model. Custom-made items can be produced by using 3DP technology. This innovation allows 3DP use in preoperative planning and surgical training. Learning is difficult among medical students because of the complex anatomical structures of the liver. Thus, 3D visualization is a useful tool in anatomy teaching and hepatic surgical training. However,conventional models do not capture haptic qualities. 3DP can produce highly accurate and complex physical models. Many types of human or animal differentiated cells can be printed successfully with the development of 3D bio-printing technology. This progress represents a valuable breakthrough that exhibits many potential uses, such as research on drug metabolism or liver disease mechanism. This technology can also be used to solve shortage of organs for transplant in the future.
文摘This paper presents a discussion of the characters and design patterns of the digital texture design in fashion fabrics. It starts from the characters of fabric texture design, taking digital printing technology as a detailed example, and raises a possible design route and pattern of the innovative design of fashion fabrics under digital technology.
基金Supported by National Natural Science Foundation of China (No. E05020203) , "863" National Hi-Tech Program(No.2002AA420050) and "973" National Key Basic Research Program ( No. 2003CB716202).
文摘To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bottom surface and wafer top surface. In nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relation between the residual re- sist thickness and the pressing force during pressing the mould toward the resist-coated wafer. Based on these analytical studies, a new imprint process, which includes a pre-cure release of the pressing force, was proposed for the high-conformity transfer of nano-patterns from the mould to the wafer. The results of a series of imprint experiments showed that the proposed loading process could meet the requirements for the imprint of different patterns and feature sizes while maintaining a uniform residual resist and non-distorted transfer of nano-patterns from the mould to the resist- coated wafer.
基金Supported by Australian Research Council's Discovery Projects fundings scheme(DP1096342)
文摘The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem: the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions (or bioacid constituents). The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.
文摘Abstract: The search for "new materials" to manufacture building elements for economical housing is the aim of this work. These materials are the following recycled plastics: Low-density polyethylene (LDPE), recycled out of discarded soft drink packs: Polyethylene-terephthalate (PET), recycled out of discarded soft drink bottles; and several plastics, from the printed films used like packages of candies (remainder of production plant by faults in the thickness of the films or in the inked process of themt. These conveniently grounded plastics were taken as "arids" to be mixed with Normal Portland cement, replacing heavy sand and gravel habitually used in these mixtures. These materials are used in constructive elements such as bricks, blocks and plates for economical houses closures or traditional construction. The developed constructive elements offer high thermal insulation, so they can be used in closures with a smaller thickness than conventional bricks and blocks. Besides, they have a lower specific weight than these traditiunal constructive elements. Recycling means lowering costs, making part of the environment contaminating waste useful and providing the unemployed and/or unqualified work force with jobs through uncomplicated technologies. Therefore, this recycling technology has an economic as well as an ecological purpose.
基金supported by the National Basic Research Program of China(2011CB965000)Chinese Academy of Sciences Strategic Priority Research Program Grants(XDA01030506)
文摘Three-dimensional(3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing.