A new solution called component modification in-process was introduced to the difficult grinding of air quenching steel slag by a series of experiments. The results show that the fly ash added into the molten steel sl...A new solution called component modification in-process was introduced to the difficult grinding of air quenching steel slag by a series of experiments. The results show that the fly ash added into the molten steel slag before air quenching can more effectively improve the slag's grindability than milltailings, which is the other modification agent tested under the same conditions. The role of fly ash is strengthened as its proportion increases, although the degree of promotion is gradually reduced. As a result of the reaction between fly ash and steel slag at high temperature, some new mineral phases and vitreous bodies with fine grindability promote the slag grinding easily. This work is helpful to making a comprehensive utilization of steel slag and maximize its economic efficiency in China.展开更多
The microstructure and tensile properties were investigated in a thick-walled section (approximately 45 mm×43 mm) of a rheocast component produced by the RheoMetalTM process.Due to the long solidification period ...The microstructure and tensile properties were investigated in a thick-walled section (approximately 45 mm×43 mm) of a rheocast component produced by the RheoMetalTM process.Due to the long solidification period of such components, it is expected that the Al-Si eutectic formed will be coarse.Therefore, sodium (Na) was used as a modifying agent to reduce the coarseness of the eutectic.Tensile test bars were machined from three different sets of materials:1) non-modified melt, 2) modified melt cast directly after Na addition, and 3) modified melt cast 30 min after Na addition.The alloy used was a secondary AlSi6Cu2.5 alloy (STENAL Rheo1), specially developed for rheocasting.The material was studied in the as-cast condition as well as after a T6 heat treatment.The results show that the Al-Si eutectic is significantly refined by the Na addition, even after a fading time of 30 min.However, it is observed that the Na modification generally has a detrimental effect on the mechanical properties, despite the structure refinement.This is especially true in the T6 heat treated condition, where the yield strength is reduced by more than 30%.Some possible mechanisms for the degradation of mechanical performance are discussed.展开更多
Aerosol particles over the coastal area are subject to the modification of their chemical composition during their transport and diffusion. For examining the modification, the marine aerosol particles are collected at...Aerosol particles over the coastal area are subject to the modification of their chemical composition during their transport and diffusion. For examining the modification, the marine aerosol particles are collected at an island, East China Sea. Comparison of elemental composition of the marine aerosols with that of the samples collected at a coastal site, e.g. in Shanghai, was made. The results of chemical analysis show that the loss of chlorine component in aerosol particles is one of the main characteristics in the course of diffusion of marine aerosols into the coastal continent. Sulphur is a dominant component for fine particles in both marine and coastal aerosols. The relation of particle number concentration and particle size distribution to the meteorological conditions was discussed briefly. These results can be used as a reference in the estimation of equivalent refractive index of the aerosols for radiation transfer.展开更多
The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on th...The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on the surface reactivity, morphology, oxygen-to-carbon （O/C） ratio of the EFB at varying treatment times. The surface reactivity is determined by the reaction of antioxidant functional groups or reactive species with 2,2-diphenyl-l-picrylhydrazyl （DPPH）. By measuring the concentration of the DPPH with a spectrophotometer, the change in the amount of antioxidant functional groups can be measured to determine the surface reactivity. The reactions of the various lignin components in the EFB with respect to the NTP treatment are discussed by qualitatively assessing the changes in the Fourier transform infrared （FTIR） spectra. The surface morphology is examined by a scanning electron microscope. To determine the amount of oxygen deposited on the EFB by the air-based NTP treatment, the oxygen and carbon contents are measured by an energy dispersive x-ray detector to determine the O/C ratio. The results show that the NTP reactor produced reactive species such as atomic oxygen and ozone, increasing the surface reactivity and chemical scavenging rate of the EFB. Consequently, the surface morphology changed, with an observed rougher surface from the images of the EFB samples. The change in the appearance of the surface is accompanied by a high O/C ratio, and is caused by reactions of certain components of lignin due to the NTP treatment, The lignin component that was modified is believed to be syringyl, as the syringyl portion in the lignin of EFBs is higher compared to the other components. Syringyl components are detected in the range of F-FIR wavenumbers of 1109-1363 cm-1. With increasing NTP treatment times, the absorbance （of the peaks in the PTIR spectra） for syringyl related C-H and lignin associated C=C bonds decreases as the syringyl decomposes. The resulting release of carboxyl compounds increases the absorbance for the carbonyl C=O group. The results show that NTP treatment is able to modify the surface properties of EFB, and that the surface reactivity can be increased to improve their conversion and processing efficiencies.展开更多
Structural and technological aspects of obtaining and processing functional composite materials based on PTFE(polytetrafluoroethylene)are considered.It is shown that,due to the features of the molecular structure of t...Structural and technological aspects of obtaining and processing functional composite materials based on PTFE(polytetrafluoroethylene)are considered.It is shown that,due to the features of the molecular structure of the matrix polymer,within the framework of the traditional technological paradigm,prerequisites are created for the implementation of a structural paradox,which manifests itself in a decrease in the parameters of the stress-strain and tribological characteristics of composites with an increase in the degree of filling.Within the framework of the concept of multilevel modification,methodological approaches to the implementation of the energy and technological compliance of components,which reduce the negative impact of the structural paradox,are considered.展开更多
Independent component analysis (ICA) has demonstrated its power to extract mass spectra from over-lapping GC/MS signal. However, there is still a problem that mass spectra with negative peaks at some m/z will be obtai...Independent component analysis (ICA) has demonstrated its power to extract mass spectra from over-lapping GC/MS signal. However, there is still a problem that mass spectra with negative peaks at some m/z will be obtained in the resolved results when there are overlapping peaks in the mass spectra of a mixture. Based on a detail theoretical analysis of the preconditions for ICA and the non-negative property of GC/MS signals, a post-modification based on chemical knowledge (PMBK) strategy is pro-posed to solve this problem. By both simulated and experimental GC/MS signals, it was proved that the PMBK strategy can improve the resolution effectively.展开更多
The SiO_2 nanoparticles were coated on the surface of graphene oxide(GO) by sol-gel method to get the SiO_2-G compound.The SiO_2-G was restored and oleophylically modified to prepare hydrophobic modified SiO_2-G(HM-Si...The SiO_2 nanoparticles were coated on the surface of graphene oxide(GO) by sol-gel method to get the SiO_2-G compound.The SiO_2-G was restored and oleophylically modified to prepare hydrophobic modified SiO_2-G(HM-SiO_2-G) which was subsequently added to silicone rubber matrix to prepare two-component room temperature vulcanized(RTV-2) thermal conductive silicone rubber. The morphology, chemical structure and dispersity of the modified graphene were characterized with SEM, FTIR, Raman, and XPS methods.In addition, the heat-resistance behavior, mechanical properties, thermal conductivity, and electrical conductivity of the RTV-2 silicone rubber were also studied systematically. The results showed that the SiO_2 nanoparticles were coated on graphene oxide successfully, and HM-SiO_2-G was uniformly dispersed in RTV-2 silicone rubber. The addition of HM-SiO_2-G could effectively improve the thermal stability, mechanical properties and thermal conductivity of RTV-2 silicone rubber and had no great influence on the electrical insulation performance.展开更多
基金Project(IRT0708) supported by Program for Changjiang Scholars and Innovative Research Team in University of China ("PCSIRT")Project(20070008031) supported by the Research Fund for the Dectoral Program of Higher Education of China
文摘A new solution called component modification in-process was introduced to the difficult grinding of air quenching steel slag by a series of experiments. The results show that the fly ash added into the molten steel slag before air quenching can more effectively improve the slag's grindability than milltailings, which is the other modification agent tested under the same conditions. The role of fly ash is strengthened as its proportion increases, although the degree of promotion is gradually reduced. As a result of the reaction between fly ash and steel slag at high temperature, some new mineral phases and vitreous bodies with fine grindability promote the slag grinding easily. This work is helpful to making a comprehensive utilization of steel slag and maximize its economic efficiency in China.
文摘The microstructure and tensile properties were investigated in a thick-walled section (approximately 45 mm×43 mm) of a rheocast component produced by the RheoMetalTM process.Due to the long solidification period of such components, it is expected that the Al-Si eutectic formed will be coarse.Therefore, sodium (Na) was used as a modifying agent to reduce the coarseness of the eutectic.Tensile test bars were machined from three different sets of materials:1) non-modified melt, 2) modified melt cast directly after Na addition, and 3) modified melt cast 30 min after Na addition.The alloy used was a secondary AlSi6Cu2.5 alloy (STENAL Rheo1), specially developed for rheocasting.The material was studied in the as-cast condition as well as after a T6 heat treatment.The results show that the Al-Si eutectic is significantly refined by the Na addition, even after a fading time of 30 min.However, it is observed that the Na modification generally has a detrimental effect on the mechanical properties, despite the structure refinement.This is especially true in the T6 heat treated condition, where the yield strength is reduced by more than 30%.Some possible mechanisms for the degradation of mechanical performance are discussed.
文摘Aerosol particles over the coastal area are subject to the modification of their chemical composition during their transport and diffusion. For examining the modification, the marine aerosol particles are collected at an island, East China Sea. Comparison of elemental composition of the marine aerosols with that of the samples collected at a coastal site, e.g. in Shanghai, was made. The results of chemical analysis show that the loss of chlorine component in aerosol particles is one of the main characteristics in the course of diffusion of marine aerosols into the coastal continent. Sulphur is a dominant component for fine particles in both marine and coastal aerosols. The relation of particle number concentration and particle size distribution to the meteorological conditions was discussed briefly. These results can be used as a reference in the estimation of equivalent refractive index of the aerosols for radiation transfer.
基金Tenaga Nasional Berhad (Malaysia) for funding this research (TNBR/SF 240/2016)
文摘The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on the surface reactivity, morphology, oxygen-to-carbon （O/C） ratio of the EFB at varying treatment times. The surface reactivity is determined by the reaction of antioxidant functional groups or reactive species with 2,2-diphenyl-l-picrylhydrazyl （DPPH）. By measuring the concentration of the DPPH with a spectrophotometer, the change in the amount of antioxidant functional groups can be measured to determine the surface reactivity. The reactions of the various lignin components in the EFB with respect to the NTP treatment are discussed by qualitatively assessing the changes in the Fourier transform infrared （FTIR） spectra. The surface morphology is examined by a scanning electron microscope. To determine the amount of oxygen deposited on the EFB by the air-based NTP treatment, the oxygen and carbon contents are measured by an energy dispersive x-ray detector to determine the O/C ratio. The results show that the NTP reactor produced reactive species such as atomic oxygen and ozone, increasing the surface reactivity and chemical scavenging rate of the EFB. Consequently, the surface morphology changed, with an observed rougher surface from the images of the EFB samples. The change in the appearance of the surface is accompanied by a high O/C ratio, and is caused by reactions of certain components of lignin due to the NTP treatment, The lignin component that was modified is believed to be syringyl, as the syringyl portion in the lignin of EFBs is higher compared to the other components. Syringyl components are detected in the range of F-FIR wavenumbers of 1109-1363 cm-1. With increasing NTP treatment times, the absorbance （of the peaks in the PTIR spectra） for syringyl related C-H and lignin associated C=C bonds decreases as the syringyl decomposes. The resulting release of carboxyl compounds increases the absorbance for the carbonyl C=O group. The results show that NTP treatment is able to modify the surface properties of EFB, and that the surface reactivity can be increased to improve their conversion and processing efficiencies.
文摘Structural and technological aspects of obtaining and processing functional composite materials based on PTFE(polytetrafluoroethylene)are considered.It is shown that,due to the features of the molecular structure of the matrix polymer,within the framework of the traditional technological paradigm,prerequisites are created for the implementation of a structural paradox,which manifests itself in a decrease in the parameters of the stress-strain and tribological characteristics of composites with an increase in the degree of filling.Within the framework of the concept of multilevel modification,methodological approaches to the implementation of the energy and technological compliance of components,which reduce the negative impact of the structural paradox,are considered.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20325517 and 20575031)the Teaching and Research Award Program for Out-standing Young Teachers in Higher Educations of MOE (TRAPOYT)
文摘Independent component analysis (ICA) has demonstrated its power to extract mass spectra from over-lapping GC/MS signal. However, there is still a problem that mass spectra with negative peaks at some m/z will be obtained in the resolved results when there are overlapping peaks in the mass spectra of a mixture. Based on a detail theoretical analysis of the preconditions for ICA and the non-negative property of GC/MS signals, a post-modification based on chemical knowledge (PMBK) strategy is pro-posed to solve this problem. By both simulated and experimental GC/MS signals, it was proved that the PMBK strategy can improve the resolution effectively.
基金the Guangdong Province Science and Technology projects(No.2017A040402005)Guangdong Bureau of Quality and Technical Supervision Science and Technology projects(No.2017CT30)for financial support of this work
文摘The SiO_2 nanoparticles were coated on the surface of graphene oxide(GO) by sol-gel method to get the SiO_2-G compound.The SiO_2-G was restored and oleophylically modified to prepare hydrophobic modified SiO_2-G(HM-SiO_2-G) which was subsequently added to silicone rubber matrix to prepare two-component room temperature vulcanized(RTV-2) thermal conductive silicone rubber. The morphology, chemical structure and dispersity of the modified graphene were characterized with SEM, FTIR, Raman, and XPS methods.In addition, the heat-resistance behavior, mechanical properties, thermal conductivity, and electrical conductivity of the RTV-2 silicone rubber were also studied systematically. The results showed that the SiO_2 nanoparticles were coated on graphene oxide successfully, and HM-SiO_2-G was uniformly dispersed in RTV-2 silicone rubber. The addition of HM-SiO_2-G could effectively improve the thermal stability, mechanical properties and thermal conductivity of RTV-2 silicone rubber and had no great influence on the electrical insulation performance.
