The control of macrosegregation is still a difficult problem for the production of large steel ingots.In order to develop new techniques for producing low-macrosegregation and high-quality steel ingots,the effect of t...The control of macrosegregation is still a difficult problem for the production of large steel ingots.In order to develop new techniques for producing low-macrosegregation and high-quality steel ingots,the effect of the heat absorption method(HAM)used by the inorganic material rods to cool the liquid steel on the formation of macrosegregation during solidification of a 5-t GCr15SiMn bearing steel ingot was studied using experiment and mathematical simulation.The inorganic material was a mixture of CaF2 and CaO.The levels of macrosegregation in the longitudinal sections of two ingots with and without HAM were compared.Experimental results showed that the application of HAM reduced the positive segregation in the upper part of the ingot and the negative segregation in the lower part.The levels of carbon segregation along the longitudinal centerline and horizontal direction at different heights were all alleviated and the fluctuation of carbon segregation was significantly reduced.The simulation results confirmed that the melting and floating of the inorganic material could carry the sensible heat to the top of the liquid steel quickly.This leads to the acceleration of the cooling rate of the liquid steel,thereby alleviating the level of macrosegregation.展开更多
In vitro experiment using excised skin has been valuable for studying the mechanism of percutaneous absorption. Based on previously established static diffusion cell system in this laboratory, a novel model-peifused g...In vitro experiment using excised skin has been valuable for studying the mechanism of percutaneous absorption. Based on previously established static diffusion cell system in this laboratory, a novel model-peifused glass diffusion cell system is desboed. The results of initial comporative study on percutaneous absorption between glass perfused diffusion cell and static diffusion cell, ih vitro and in vivo permeation as well as factors affecting permeation with seven radiolabelled chemicals are presented. The results demonstrate that the peifused diffusion cell system, which used a perfusion nuid betow the suiface of skin to take up the materials which penetrated the skin, is more similar to physiologic condition,convenient and automatic than that of the static cell. It well predicts the in vivo percutaneous absorption if appropriate areptor fluid is chosen. The results also show that the selection of receptor fluid is critical for in vitro permeation of chemicals with different soubility展开更多
Based on theoretical calculation and Monte Carlo simulation,this paper proposes a new method for the diagnosing of 16.7 MeV high-energy pulse gamma,named "scattering absorption method". The ratio of the sens...Based on theoretical calculation and Monte Carlo simulation,this paper proposes a new method for the diagnosing of 16.7 MeV high-energy pulse gamma,named "scattering absorption method". The ratio of the sensitivity of high-energy gamma to that of the low-energy background gamma can reach 106 to 108 by this new method. The sensitivity of 16.7 MeV high-energy gamma ranges from 10-21 to 10-16 C·cm2. It's better than the traditional method which is based on the magnetic analyzer and Cherenkov detector on some aspects.展开更多
The complexation of gallium with 2-hydroxy-5-T-butylphenol-4’-methoxy-azobenzene (HR) has been studied by atomic absorption and spectrophotometric methods. The optimal conditions for the formation and extraction of t...The complexation of gallium with 2-hydroxy-5-T-butylphenol-4’-methoxy-azobenzene (HR) has been studied by atomic absorption and spectrophotometric methods. The optimal conditions for the formation and extraction of the complex were found. The maximum light absorption of the complex in n-butanol is in the range of 450 - 470 nm. The molar absorption coefficient is (3.3 - 4.2)<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>10<sup>4</sup>. The stability constant of the gallium coordination compound in n-butanol is <em>β</em><sub>l</sub> = 4.2<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>10<sup>10</sup>. The developed technique allows to determine the gallium content within n × 10<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> - n × 10<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>4</sup>%. The selective and sensitive technique for the extraction-atomic absorption determination of gallium in soils has been developed.展开更多
The composite that can absorb the high-performance electromagnetic(EM) wave is constructed into a sandwiched structure composed of carbon black(CB)/ethylene-vinyl acetate(EVA) and Ag naowires(Ag NWs). The Ag N...The composite that can absorb the high-performance electromagnetic(EM) wave is constructed into a sandwiched structure composed of carbon black(CB)/ethylene-vinyl acetate(EVA) and Ag naowires(Ag NWs). The Ag NWs sandwiched between two CB/EVA layers are used to improve the absorption properties of composite. The effects of EVA-to-CB weight ratio, concentration and diameter of Ag NWs with a thickness of 0.4 mm on microwave absorption are investigated.The results indicate that for an EVA-to-CB weight ratio of 1:3, Ag NW concentration of 1.0 mg/100 m L, and average diameter of 56 nm, the reflection loss(RL) of the composite is below-10 d B in a frequency range of 9.3 Ghz–18.0 GHz, with the minimum values of-40.0 d B and-25.6 d B at 13.5 GHz and 15.3 GHz, respectively. A finite element method(FEM)is used for calculating the RL of the composite. The calculated results are in agreement with the experimental data.展开更多
It has been demonstrated that heat absorption method by using the inorganic material rod to cool the molten steel can significantly reduce the macrosegregation level of the large steel ingot.However,owing to the opaci...It has been demonstrated that heat absorption method by using the inorganic material rod to cool the molten steel can significantly reduce the macrosegregation level of the large steel ingot.However,owing to the opacity of the molten steel,the physical mechanism of the heat absorption method is not clear.In this work,a transparent hydraulic physical model with water and paraffin wax was built to simulate the melting and floating processes of inorganic materials in the molten steel.A mathematical simulation was also carried out to analyze the connection between the actual ingot and the physical model.Results show that it is feasible to simulate the molten steel and inorganic materials with water and paraffin wax.With the help of the physical model,the process of the melting of paraffin wax and its floating to the surface of water were clearly observed,during which the temperature of water at some characteristic positions in the mold was recorded.The visualization findings demonstrate that the melting and floating processes of paraffin wax can help to bring the heat from the center of the mold to the top surface more quickly,which reduces the superheat and significantly accelerates the cooling rate of water.The experimental results show that for the water with a certain superheat,the use of a larger mass of paraffin wax can accelerate the cooling of the water,but there is a risk of incomplete melting of the paraffin wax.A higher superheat of water will lead to a quicker melting rate for a given mass of paraffin wax,while a lower superheat leads to the incomplete melting of paraffin wax as well.展开更多
Curcumin aqueous extract is used successfully as a green corrosion inhibitor at quasi-cooking conditions (90℃) to inhibit leaching from Aluminum cook wares in solutions containing vegetables or meat. Aluminum cook wa...Curcumin aqueous extract is used successfully as a green corrosion inhibitor at quasi-cooking conditions (90℃) to inhibit leaching from Aluminum cook wares in solutions containing vegetables or meat. Aluminum cook wares were bought from the market from four countries and cut to make the Aluminum samples. Six types of vegetables and three kinds of meat were chosen. Each type of vegetable and meat was used to prepare 30% w/v aqueous solutions. Three methods were used in the present study: Gravimetric method, Atomic Absorption and FTIR. Gravimetric method was applied to determine the leaching rate and the corrosion inhibition efficiency with/without NaCl. The effect of Curcumin concentration, Tab water, immersion time, alloying elements was investigated. There was a good consistency between Gravimetric and Atomic Absorption methods. The adsorption of Curcumin on the aluminum surface was in accordance with Langmuir isotherm. The values of the adsorption constant (K<sub>ads</sub>) and the free energy of adsorption (G<sub>ads</sub>o</sup>) were calculated and discussed. FTIR spectrum indicated that Curcumin coordinated with Al<sup>3+</sup> resulting in the formation of Al<sup>3+</sup>-Curcumin complex on the metal surface. Using a small amount of Curcumin decreased leaching from Aluminum cook wares into food by 60% - 80% depending about the type of food.展开更多
A multi-functional solar and skylight spectrophotometer has been developed for the study of atmospheric constituents and aerosols. The instrument and its performance are described. Due to telescope structure and lock-...A multi-functional solar and skylight spectrophotometer has been developed for the study of atmospheric constituents and aerosols. The instrument and its performance are described. Due to telescope structure and lock-in amplification technique adopted,the sensitivity of the instrument is high enough to conduct direct sun moon and twilight measurement for several atmospheric species and the degree of polarization and intensity observation for sky light. From measured results, the total column abundance of atmospheric species and the optical characteristics of aerosol can be retrieved. In this paper, the daily averaged column abundance of O_3 measured in Beijing by direct sun was compared with Dobson spectrophotometer nearby. The two did not show significant difference.展开更多
Optical absorption in thin-film solar cells can be improved by using surface plasmons for guiding and confining the light on the nanoscale.We report theoretical and simulation studies of a-Si thin-film solar cells wit...Optical absorption in thin-film solar cells can be improved by using surface plasmons for guiding and confining the light on the nanoscale.We report theoretical and simulation studies of a-Si thin-film solar cells with silver nanocylinders on the surface.We found that surface plasmons increased the cells' spectral response over almost the entire studied solar spectrum.In the ultraviolet range and at wavelengths close to the Si band gap we observed a significant enhancement of the absorption for both thin-film and wafer-based structures.We also performed optimization studies of particle size,inter-particle distance,and dielectric environment,for obtaining maximal absorption within the substrate.A blue-shift of the resonance wavelength with increasing inter-particle distance was observed in the visible range.Cell performance improved at optimal spacing,which strongly depended on the nanoparticle size.Increasing the nanocylinder size was accompanied by the widening of the plasmon resonance band and a red-shift of the plasmon resonance peaks.A weak red-shift and plasmon peak enhancement were observed in the reflectance curve with increasing refractive index of the dielectric spacer.展开更多
基金This work was supported by National Key R&D Program of China(Grant No.2019YFA0705303)National Natural Science Foundation of China(Grant No.52127807)+2 种基金National Science and Technology Major Project"Aeroengine and Gas Turbine"(Grant No.2017-VII-0008-0102)Independent Research and Development Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2020-Z05)the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200).
文摘The control of macrosegregation is still a difficult problem for the production of large steel ingots.In order to develop new techniques for producing low-macrosegregation and high-quality steel ingots,the effect of the heat absorption method(HAM)used by the inorganic material rods to cool the liquid steel on the formation of macrosegregation during solidification of a 5-t GCr15SiMn bearing steel ingot was studied using experiment and mathematical simulation.The inorganic material was a mixture of CaF2 and CaO.The levels of macrosegregation in the longitudinal sections of two ingots with and without HAM were compared.Experimental results showed that the application of HAM reduced the positive segregation in the upper part of the ingot and the negative segregation in the lower part.The levels of carbon segregation along the longitudinal centerline and horizontal direction at different heights were all alleviated and the fluctuation of carbon segregation was significantly reduced.The simulation results confirmed that the melting and floating of the inorganic material could carry the sensible heat to the top of the liquid steel quickly.This leads to the acceleration of the cooling rate of the liquid steel,thereby alleviating the level of macrosegregation.
文摘In vitro experiment using excised skin has been valuable for studying the mechanism of percutaneous absorption. Based on previously established static diffusion cell system in this laboratory, a novel model-peifused glass diffusion cell system is desboed. The results of initial comporative study on percutaneous absorption between glass perfused diffusion cell and static diffusion cell, ih vitro and in vivo permeation as well as factors affecting permeation with seven radiolabelled chemicals are presented. The results demonstrate that the peifused diffusion cell system, which used a perfusion nuid betow the suiface of skin to take up the materials which penetrated the skin, is more similar to physiologic condition,convenient and automatic than that of the static cell. It well predicts the in vivo percutaneous absorption if appropriate areptor fluid is chosen. The results also show that the selection of receptor fluid is critical for in vitro permeation of chemicals with different soubility
文摘Based on theoretical calculation and Monte Carlo simulation,this paper proposes a new method for the diagnosing of 16.7 MeV high-energy pulse gamma,named "scattering absorption method". The ratio of the sensitivity of high-energy gamma to that of the low-energy background gamma can reach 106 to 108 by this new method. The sensitivity of 16.7 MeV high-energy gamma ranges from 10-21 to 10-16 C·cm2. It's better than the traditional method which is based on the magnetic analyzer and Cherenkov detector on some aspects.
文摘The complexation of gallium with 2-hydroxy-5-T-butylphenol-4’-methoxy-azobenzene (HR) has been studied by atomic absorption and spectrophotometric methods. The optimal conditions for the formation and extraction of the complex were found. The maximum light absorption of the complex in n-butanol is in the range of 450 - 470 nm. The molar absorption coefficient is (3.3 - 4.2)<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>10<sup>4</sup>. The stability constant of the gallium coordination compound in n-butanol is <em>β</em><sub>l</sub> = 4.2<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>10<sup>10</sup>. The developed technique allows to determine the gallium content within n × 10<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> - n × 10<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>4</sup>%. The selective and sensitive technique for the extraction-atomic absorption determination of gallium in soils has been developed.
基金Project partly supported by the National Natural Science Foundation of China(Grant No.61275174)
文摘The composite that can absorb the high-performance electromagnetic(EM) wave is constructed into a sandwiched structure composed of carbon black(CB)/ethylene-vinyl acetate(EVA) and Ag naowires(Ag NWs). The Ag NWs sandwiched between two CB/EVA layers are used to improve the absorption properties of composite. The effects of EVA-to-CB weight ratio, concentration and diameter of Ag NWs with a thickness of 0.4 mm on microwave absorption are investigated.The results indicate that for an EVA-to-CB weight ratio of 1:3, Ag NW concentration of 1.0 mg/100 m L, and average diameter of 56 nm, the reflection loss(RL) of the composite is below-10 d B in a frequency range of 9.3 Ghz–18.0 GHz, with the minimum values of-40.0 d B and-25.6 d B at 13.5 GHz and 15.3 GHz, respectively. A finite element method(FEM)is used for calculating the RL of the composite. The calculated results are in agreement with the experimental data.
基金supported by Shanghai Post-doctoral Excellence Program of China(No.2021166)Shanghai Rising-Star Program(Nos.20QA1403800 and 21QC1401500)Shanghai Science and Technology Committee(No.21511103600).
文摘It has been demonstrated that heat absorption method by using the inorganic material rod to cool the molten steel can significantly reduce the macrosegregation level of the large steel ingot.However,owing to the opacity of the molten steel,the physical mechanism of the heat absorption method is not clear.In this work,a transparent hydraulic physical model with water and paraffin wax was built to simulate the melting and floating processes of inorganic materials in the molten steel.A mathematical simulation was also carried out to analyze the connection between the actual ingot and the physical model.Results show that it is feasible to simulate the molten steel and inorganic materials with water and paraffin wax.With the help of the physical model,the process of the melting of paraffin wax and its floating to the surface of water were clearly observed,during which the temperature of water at some characteristic positions in the mold was recorded.The visualization findings demonstrate that the melting and floating processes of paraffin wax can help to bring the heat from the center of the mold to the top surface more quickly,which reduces the superheat and significantly accelerates the cooling rate of water.The experimental results show that for the water with a certain superheat,the use of a larger mass of paraffin wax can accelerate the cooling of the water,but there is a risk of incomplete melting of the paraffin wax.A higher superheat of water will lead to a quicker melting rate for a given mass of paraffin wax,while a lower superheat leads to the incomplete melting of paraffin wax as well.
文摘Curcumin aqueous extract is used successfully as a green corrosion inhibitor at quasi-cooking conditions (90℃) to inhibit leaching from Aluminum cook wares in solutions containing vegetables or meat. Aluminum cook wares were bought from the market from four countries and cut to make the Aluminum samples. Six types of vegetables and three kinds of meat were chosen. Each type of vegetable and meat was used to prepare 30% w/v aqueous solutions. Three methods were used in the present study: Gravimetric method, Atomic Absorption and FTIR. Gravimetric method was applied to determine the leaching rate and the corrosion inhibition efficiency with/without NaCl. The effect of Curcumin concentration, Tab water, immersion time, alloying elements was investigated. There was a good consistency between Gravimetric and Atomic Absorption methods. The adsorption of Curcumin on the aluminum surface was in accordance with Langmuir isotherm. The values of the adsorption constant (K<sub>ads</sub>) and the free energy of adsorption (G<sub>ads</sub>o</sup>) were calculated and discussed. FTIR spectrum indicated that Curcumin coordinated with Al<sup>3+</sup> resulting in the formation of Al<sup>3+</sup>-Curcumin complex on the metal surface. Using a small amount of Curcumin decreased leaching from Aluminum cook wares into food by 60% - 80% depending about the type of food.
文摘A multi-functional solar and skylight spectrophotometer has been developed for the study of atmospheric constituents and aerosols. The instrument and its performance are described. Due to telescope structure and lock-in amplification technique adopted,the sensitivity of the instrument is high enough to conduct direct sun moon and twilight measurement for several atmospheric species and the degree of polarization and intensity observation for sky light. From measured results, the total column abundance of atmospheric species and the optical characteristics of aerosol can be retrieved. In this paper, the daily averaged column abundance of O_3 measured in Beijing by direct sun was compared with Dobson spectrophotometer nearby. The two did not show significant difference.
文摘Optical absorption in thin-film solar cells can be improved by using surface plasmons for guiding and confining the light on the nanoscale.We report theoretical and simulation studies of a-Si thin-film solar cells with silver nanocylinders on the surface.We found that surface plasmons increased the cells' spectral response over almost the entire studied solar spectrum.In the ultraviolet range and at wavelengths close to the Si band gap we observed a significant enhancement of the absorption for both thin-film and wafer-based structures.We also performed optimization studies of particle size,inter-particle distance,and dielectric environment,for obtaining maximal absorption within the substrate.A blue-shift of the resonance wavelength with increasing inter-particle distance was observed in the visible range.Cell performance improved at optimal spacing,which strongly depended on the nanoparticle size.Increasing the nanocylinder size was accompanied by the widening of the plasmon resonance band and a red-shift of the plasmon resonance peaks.A weak red-shift and plasmon peak enhancement were observed in the reflectance curve with increasing refractive index of the dielectric spacer.