The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Aver...The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Average current density and reverse anodic current density amongst the variables investigated have very strong effects on the cobalt content in the Zn-Co alloy deposits. Grain size, surface appearance and internal stress in the deposit were improved significantly by introducing the reverse current. Varieties of Zn-Co alloy compositionally modulated multilayer (CMM) coatings with large differences in cobalt contents for different sublayers were electrodeposited by designing corresponding waveforms using a computer-aided pulse plater and characterized in terms of surface morphologies. Cross-sectional morphologies of the Zn-Co alloy CMM coatings, examined using field emission gun scanning electron microscopy (FEGSEM), confirmed the layered structure.展开更多
Converting sunlight directly to fuels and chemicals is a great latent capacity for storing renewable energy.Due to the advantages of large surface area,short diffusion paths for electrons,and more exposed active sites...Converting sunlight directly to fuels and chemicals is a great latent capacity for storing renewable energy.Due to the advantages of large surface area,short diffusion paths for electrons,and more exposed active sites,few‐layer carbon nitride(FLCN)materials present great potential for production of solar fuels and chemicals and set off a new wave of research in the last few years.Herein,the recent progress in synthesis and regulation of FLCN‐based photocatalysts,and their applications in the conversion of sunlight into fuels and chemicals,is summarized.More importantly,the regulation strategies from chemical modification to microstructure control toward the production of solar fuels and chemicals has been deeply analyzed,aiming to inspire critical thinking about the effective approaches for photocatalyst modification rather than developing new materials.At the end,the key scientific challenges and some future trend of FLCN‐based materials as advanced photocatalysts are also discussed.展开更多
Modeling vapor pressure is crucial for studying the moisture reliability of microelectronics, as high vapor pressure can cause device failures in environments with high temperature and humidity. To minimize the impact...Modeling vapor pressure is crucial for studying the moisture reliability of microelectronics, as high vapor pressure can cause device failures in environments with high temperature and humidity. To minimize the impact of vapor pressure, a super-hydrophobic(SH) coating can be applied on the exterior surface of devices in order to prevent moisture penetration. The underlying mechanism of SH coating for enhancing device reliability, however, is still not fully understood. In this paper, we present several existing theories for predicting vapor pressure within microelectronic materials. In addition, we discuss the mechanism and effectiveness of SH coating in preventing water vapor from entering a device, based on experimental results. Two theoretical models, a micro-mechanics-based whole-field vapor pressure model and a convection-diffusion model, are described for predicting vapor pressure. Both methods have been successfully used to explain experimental results on uncoated samples. However, when a device was coated with an SH nanocomposite, weight gain was still observed, likely due to vapor penetration through the SH surface. This phenomenon may cast doubt on the effectiveness of SH coatings in microelectronic devices. Based on current theories and the available experimental results, we conclude that it is necessary to develop a new theory to understand how water vapor penetrates through SH coatings and impacts the materials underneath. Such a theory could greatly improve microelectronics reliability.展开更多
Using the compound materials and double e-gun evaporation,the compound optical films have been successfully deposited on K9 glass substrate.The refractive index of optical compund films deposited in diffeent parameter...Using the compound materials and double e-gun evaporation,the compound optical films have been successfully deposited on K9 glass substrate.The refractive index of optical compund films deposited in diffeent parameters have been measured and theoretical formula for calculation refractive index of compound films have been derived.It is shown that the experimental curve for the variation of refractive index with wavelength in 0.4￣1.4 μm region and the theoretical one agree very well.Using these films,the laser reflecting mirror has been successfully coated.展开更多
Limited by serious heterogeneity both horizontally and vertically, water driving of low-permeability layers in Qiaokou oilfield appears to be very difficult. As the classⅠ layer reaches the stage of high water-conten...Limited by serious heterogeneity both horizontally and vertically, water driving of low-permeability layers in Qiaokou oilfield appears to be very difficult. As the classⅠ layer reaches the stage of high water-content too early, the level of exploitation became worse with low-recovery. Regarding the serious heterogeneity and low recovery in layers class Ⅱand Ⅲ, composite fracturing technology suitable for this kind of reservoir was applied. Its basement was a lab study of indoor water driving efficiency and fracturing experiment. Perfect result has achieved by using the technology.展开更多
A contraction-expansion helical mixer which combines several features, viz. helical pipes for induction of secondary flows and sudden expansion and contraction array tor expansion vortices, has been designed to en- ha...A contraction-expansion helical mixer which combines several features, viz. helical pipes for induction of secondary flows and sudden expansion and contraction array tor expansion vortices, has been designed to en- hance flow mixing. A fast competitive-consecutive diazo coupling reaction is used to test the mixing efficiency of contraction-expansion helical mixer. Furthermore, an image processing technique is applied for data visualization and monitoring the extent of mixing. The mixing performance is found to be superior in comparison to the regular helical mixer in the range of Reynolds number from 170 to 1540. Moreover, the mixing time of contraction-expansion helical mixer was found to be reduced by more than 25% compared to the regular helical pipe. Finally, a simple correlation is proposed for predicting the mixing time.展开更多
Based on the thermal tomography technology, this thesis tries to calculate quantity and distribution of heat source in vivo from body surface temperature. A superposition temperature image of a number of point heat so...Based on the thermal tomography technology, this thesis tries to calculate quantity and distribution of heat source in vivo from body surface temperature. A superposition temperature image of a number of point heat sources is surface fitted to get the Q of heat sources (information of cancer cells) quantitatively. The result can reflect the disease area information because cancer cell's Q value is much higher than that of normal cell. This application is a new try in the diagnosis of breast cancer, which has an important value on the early detection and diagnosis of disease source.展开更多
Mo-based alloys are widely used for their excellent wear and corrosion resistance as well as high temperature resistance.Mo-NiCrBSi and Mo-Ni alloy coatings were prepared on 1020 water wall tube by laser cladding tech...Mo-based alloys are widely used for their excellent wear and corrosion resistance as well as high temperature resistance.Mo-NiCrBSi and Mo-Ni alloy coatings were prepared on 1020 water wall tube by laser cladding technology in the present study.The microstructure and phase compositions were analyzed by means of the scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS)and X-ray diffractometry(XRD).The corrosion properties of the coatings were evaluated by an electrochemical experiment at room temperature in 3.5 wt.%NaCl electrolyte.With increasing content of Mo,the structure homogeneity in Mo-Ni coatings deteriorated,the grain size increased,the average hardness and the corrosion resistance declined,due to the more content of harmful phases.Compared to the Mo-Ni coatings,the overall performance was better for the Mo-NiCrBSi,which had the higher hardness contributed by the element B and Si as well as the better corrosion resistance due to the addition of Cr.展开更多
Researches on wood nanocomposites, which involve nano science and technology, wood science,materials science and other related subjects, have important science signification and promising prospect forthe development a...Researches on wood nanocomposites, which involve nano science and technology, wood science,materials science and other related subjects, have important science signification and promising prospect forthe development and study of new wood composites with high appending values and multi-properties. Thispaper reviewed the conventional wood composites, and then discussed the approaches to prepare woodnanocomposites. Based on the achievements of researches on polymer/montmorillonite (MMT)nanocomposites, the design ideas of preparing nanocomposites of wood and inorganic MMT weresystematically put forward. Nano compounding of wood and other materials is an effective approach togreatly improve or modify wood.展开更多
文摘The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Average current density and reverse anodic current density amongst the variables investigated have very strong effects on the cobalt content in the Zn-Co alloy deposits. Grain size, surface appearance and internal stress in the deposit were improved significantly by introducing the reverse current. Varieties of Zn-Co alloy compositionally modulated multilayer (CMM) coatings with large differences in cobalt contents for different sublayers were electrodeposited by designing corresponding waveforms using a computer-aided pulse plater and characterized in terms of surface morphologies. Cross-sectional morphologies of the Zn-Co alloy CMM coatings, examined using field emission gun scanning electron microscopy (FEGSEM), confirmed the layered structure.
文摘Converting sunlight directly to fuels and chemicals is a great latent capacity for storing renewable energy.Due to the advantages of large surface area,short diffusion paths for electrons,and more exposed active sites,few‐layer carbon nitride(FLCN)materials present great potential for production of solar fuels and chemicals and set off a new wave of research in the last few years.Herein,the recent progress in synthesis and regulation of FLCN‐based photocatalysts,and their applications in the conversion of sunlight into fuels and chemicals,is summarized.More importantly,the regulation strategies from chemical modification to microstructure control toward the production of solar fuels and chemicals has been deeply analyzed,aiming to inspire critical thinking about the effective approaches for photocatalyst modification rather than developing new materials.At the end,the key scientific challenges and some future trend of FLCN‐based materials as advanced photocatalysts are also discussed.
基金the support of the National High-Tech Research and Development Program of China (863 Program) (2015AA03A101)
文摘Modeling vapor pressure is crucial for studying the moisture reliability of microelectronics, as high vapor pressure can cause device failures in environments with high temperature and humidity. To minimize the impact of vapor pressure, a super-hydrophobic(SH) coating can be applied on the exterior surface of devices in order to prevent moisture penetration. The underlying mechanism of SH coating for enhancing device reliability, however, is still not fully understood. In this paper, we present several existing theories for predicting vapor pressure within microelectronic materials. In addition, we discuss the mechanism and effectiveness of SH coating in preventing water vapor from entering a device, based on experimental results. Two theoretical models, a micro-mechanics-based whole-field vapor pressure model and a convection-diffusion model, are described for predicting vapor pressure. Both methods have been successfully used to explain experimental results on uncoated samples. However, when a device was coated with an SH nanocomposite, weight gain was still observed, likely due to vapor penetration through the SH surface. This phenomenon may cast doubt on the effectiveness of SH coatings in microelectronic devices. Based on current theories and the available experimental results, we conclude that it is necessary to develop a new theory to understand how water vapor penetrates through SH coatings and impacts the materials underneath. Such a theory could greatly improve microelectronics reliability.
文摘Using the compound materials and double e-gun evaporation,the compound optical films have been successfully deposited on K9 glass substrate.The refractive index of optical compund films deposited in diffeent parameters have been measured and theoretical formula for calculation refractive index of compound films have been derived.It is shown that the experimental curve for the variation of refractive index with wavelength in 0.4￣1.4 μm region and the theoretical one agree very well.Using these films,the laser reflecting mirror has been successfully coated.
文摘Limited by serious heterogeneity both horizontally and vertically, water driving of low-permeability layers in Qiaokou oilfield appears to be very difficult. As the classⅠ layer reaches the stage of high water-content too early, the level of exploitation became worse with low-recovery. Regarding the serious heterogeneity and low recovery in layers class Ⅱand Ⅲ, composite fracturing technology suitable for this kind of reservoir was applied. Its basement was a lab study of indoor water driving efficiency and fracturing experiment. Perfect result has achieved by using the technology.
基金Supported by the National Key Technology R&D Program(2011BAE07B01)the National Natural Science Foundation of China(20836001)
文摘A contraction-expansion helical mixer which combines several features, viz. helical pipes for induction of secondary flows and sudden expansion and contraction array tor expansion vortices, has been designed to en- hance flow mixing. A fast competitive-consecutive diazo coupling reaction is used to test the mixing efficiency of contraction-expansion helical mixer. Furthermore, an image processing technique is applied for data visualization and monitoring the extent of mixing. The mixing performance is found to be superior in comparison to the regular helical mixer in the range of Reynolds number from 170 to 1540. Moreover, the mixing time of contraction-expansion helical mixer was found to be reduced by more than 25% compared to the regular helical pipe. Finally, a simple correlation is proposed for predicting the mixing time.
文摘Based on the thermal tomography technology, this thesis tries to calculate quantity and distribution of heat source in vivo from body surface temperature. A superposition temperature image of a number of point heat sources is surface fitted to get the Q of heat sources (information of cancer cells) quantitatively. The result can reflect the disease area information because cancer cell's Q value is much higher than that of normal cell. This application is a new try in the diagnosis of breast cancer, which has an important value on the early detection and diagnosis of disease source.
基金supported by the National Natural Science Foundation of China(Grant Nos.11372110and 51101056)+1 种基金the National Science and Technology Support Program(Grant No.2011BAE12B03)the Fundamental Research Funds for the Central Universities(Grant No.12MS07)
文摘Mo-based alloys are widely used for their excellent wear and corrosion resistance as well as high temperature resistance.Mo-NiCrBSi and Mo-Ni alloy coatings were prepared on 1020 water wall tube by laser cladding technology in the present study.The microstructure and phase compositions were analyzed by means of the scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS)and X-ray diffractometry(XRD).The corrosion properties of the coatings were evaluated by an electrochemical experiment at room temperature in 3.5 wt.%NaCl electrolyte.With increasing content of Mo,the structure homogeneity in Mo-Ni coatings deteriorated,the grain size increased,the average hardness and the corrosion resistance declined,due to the more content of harmful phases.Compared to the Mo-Ni coatings,the overall performance was better for the Mo-NiCrBSi,which had the higher hardness contributed by the element B and Si as well as the better corrosion resistance due to the addition of Cr.
文摘Researches on wood nanocomposites, which involve nano science and technology, wood science,materials science and other related subjects, have important science signification and promising prospect forthe development and study of new wood composites with high appending values and multi-properties. Thispaper reviewed the conventional wood composites, and then discussed the approaches to prepare woodnanocomposites. Based on the achievements of researches on polymer/montmorillonite (MMT)nanocomposites, the design ideas of preparing nanocomposites of wood and inorganic MMT weresystematically put forward. Nano compounding of wood and other materials is an effective approach togreatly improve or modify wood.
