The evolution of hardness and microstructures of 1050 aluminum alloy prepared by hot rolling and subsequent equal- channel angular pressing at cryogenic temperature (cryoECAP) after annealing at 150?400 °C for 1 ...The evolution of hardness and microstructures of 1050 aluminum alloy prepared by hot rolling and subsequent equal- channel angular pressing at cryogenic temperature (cryoECAP) after annealing at 150?400 °C for 1 h without and with magnetic field of 12 T was investigated. The electron back scattering diffraction pattern (EBSD) and transmission electron microscopy (TEM) were utilized to characterize the grain microstructures and dislocations. It is demonstrated that the hot rolling before cryoECAP produces more equiaxed grains with a smaller average size and a higher fraction of high angle boundaries (HABs) in the subsequent cryoECAPed 1050 aluminum alloy, thus accelerating the recovery and recrystallization of cryoECAPed alloy and produces more homogeneous microstructure during annealing. The magnetic field promotes the recovery and recrystallization and leads to much lower hardness at 150?250 °C, while it can suppress the abnormal grain growth and form more homogeneous grain size distributions annealed at 300?400 °C.展开更多
High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic field as a field source. It has higher resolution and greater depth penetration than th...High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic field as a field source. It has higher resolution and greater depth penetration than the direct current method and is especially fit for geothermal energy exploration and low- and mid-level groundwater detection. We introduce a successful application of high-frequency electromagnetic sounding for evaluating geothermal water resources. The high frequency electromagnetic system (MT-USA with a frequency range from 10 KHz to 1 Hz) is first applied to sample field data from China. A remote reference station is used to assure sampled data quality. We then perform 2D inversion image processing with the electrical method data. The results basically indicate the spatial distribution of underground geothermal water and provide favorable clues to finding the sources of the subsurface geothermal water in this area.展开更多
The effect of sintering temperature on the structure, magnetic transition and magnetic entropy of La0.6Ca0.4MnO3 manganite was studied. It was observed that this compound belongs to the orthorhombic structure with the...The effect of sintering temperature on the structure, magnetic transition and magnetic entropy of La0.6Ca0.4MnO3 manganite was studied. It was observed that this compound belongs to the orthorhombic structure with the Pnma space group without any impurity phase. The effect of sintering temperature on the Curie temperature(TC) was studied. The small increment in TC is found with increasing the sintering temperature. The magnetocaloric study exposes a quite large change of the magnetic entropy, which varies with sintering temperature. For an applied magnetic field of 3 T and sintering temperature of 1300 °C, the relative cooling power(RCP) is 89 J/kg. As a result, the studied compound can be considered as potential material for magnetic refrigeration near and below room temperature.展开更多
The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu_2(CeCu_2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of ...The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu_2(CeCu_2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of HoCu_2 were a mixture of Cu, unknown hydride Ⅰ, and unknown hydride Ⅱ. Based on the PCT(pressure-concentration-temperature) curves under different reaction temperatures, the relationships among reaction temperature, equilibrium pressure, and maximum hydrogen absorption capacity were analyzed and discussed. The enthalpy change ΔH and entropy change ΔS as a result of the whole hydrogenation process were also calculated from the PCT curves. The magnetization and volumetric specific heat capacity of the hydride were also measured by SQUID magnetometer and PPMS, respectively.展开更多
A novel magnetic adsorbent was synthesized by magnetizing bentonite by APTES-Fe_3O_4 via a functional groupbridged interaction. The characterization of APTES-Fe_3O_4/bentonite was conducted via transmission electron m...A novel magnetic adsorbent was synthesized by magnetizing bentonite by APTES-Fe_3O_4 via a functional groupbridged interaction. The characterization of APTES-Fe_3O_4/bentonite was conducted via transmission electron microscope(TEM), X-ray diffraction(XRD), Fourier transform infrared spectrophotometer(FT-IR), thermal gravimetric analysis(TGA), vibrating sample magnetometer(VSM), zeta potential analysis and Brunner–Emmet–Teller(BET). The APTES-Fe_3O_4/bentonite was assessed as adsorbents for methylene blue(MB) with a high adsorption capacity(91.83 mg·g^(-1)). Factors affecting the adsorption of MB(such as p H, equilibrium time, temperature and initial concentration) were investigated. The adsorption process completely reaches equilibrium after 120 min and the maximum sorption is achieved at p H 8.0. The adsorption trend follows the pseudosecond order kinetics model. The adsorption data gives good fits with Langmuir isotherm model. The parameter factor RLfalls between 0 and 1, indicating the adsorption of MB is favorable. The adsorption process is endothermic with positive ΔH^0 values. The positive values of ΔG^0 confirm the affinity of the adsorbent towards MB, and suggest an increased randomness at the solid–liquid interface during the adsorption process. Regeneration of the saturated adsorbent was easily carried out via gamma-irradiation.展开更多
The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier tr...The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier transform infrared spectroscopy (FTIR), and H20 adsorption mechanism on the surface of lignite pyrolysis was inferred. Two major changes in the pore structure of lignite char were observed as temperature increased in 105-200 ℃ and 500-700 ℃. Pyrolysis temperature is a significant factor in removing carboxyl and phenolic hydroxyl from lignite. Variation of ether bond content can be divided into three stages; the content initially increased, then decreased, and finally increased. The equilibrium adsorption ratio, content of oxygen-containing groups, and variation of pore volume below 700° were closely correlated with each other. The amount of adsorbed water on char pyrolyzed at 700 ℃ increased. Moreover, the adsorption capacity of the lignite decreased, and the adsorption state changed.展开更多
A repulsive vortex\|vortex interaction model was used to numerically study the melting transition of the two\|dimensional vortex system with Monte Carlo method. Then a δ\|function\|like peak in the specific heat was ...A repulsive vortex\|vortex interaction model was used to numerically study the melting transition of the two\|dimensional vortex system with Monte Carlo method. Then a δ\|function\|like peak in the specific heat was observed and the internal energy showed a sharp drop at the melting temperature, which indicated that there exists a first\|order melting transition at finite temperatures. The Lindemann criterion was also investigated and valid, but different from previous simulation results.展开更多
The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of (E)-13-ocimene. Myrrh was extracted with hexane to avoid inducing c...The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of (E)-13-ocimene. Myrrh was extracted with hexane to avoid inducing changes in the constituents and odor. The main constituent, (E)-L3-ocimene (group A; low boiling point), and the other constituents (group B; high boiling point) of the hexane extract were separated by bulb-to-bulb distillation. The constituents of groups A and B were analyzed over time by nuclear magnetic resonance analysis and the odors were evaluated. Myrrh's odor depended on both the amount of thermally unstable (E)-[3-ocimene, which contributed to the fresh odor, and the constituents of group B (thermally stable), which contributed to the myrrh-like odor. Six compounds (c^-santalene, (Z)-a-bisabolene, c^-bergamotene, (E)-ct-santalal, c^-photosantalol and campherenol) were isolated from group B. No individual group B component had a myrrh-like odor, although the combined odor of group B was myrrh like. The authors demonstrated that the aroma profile of myrrh depends on the thermal instability of (E)-^-ocimene and a combination of six thermally stable terpenes with similar molecular structures.展开更多
基金Project(2011CB606403)supported by the State Basic Research Development Program of ChinaProjects(51171044,51174058)supported by the National Natural Science Foundation of ChinaProject(2012CB723307)supported by the State Basic Research Development Program of China
文摘The evolution of hardness and microstructures of 1050 aluminum alloy prepared by hot rolling and subsequent equal- channel angular pressing at cryogenic temperature (cryoECAP) after annealing at 150?400 °C for 1 h without and with magnetic field of 12 T was investigated. The electron back scattering diffraction pattern (EBSD) and transmission electron microscopy (TEM) were utilized to characterize the grain microstructures and dislocations. It is demonstrated that the hot rolling before cryoECAP produces more equiaxed grains with a smaller average size and a higher fraction of high angle boundaries (HABs) in the subsequent cryoECAPed 1050 aluminum alloy, thus accelerating the recovery and recrystallization of cryoECAPed alloy and produces more homogeneous microstructure during annealing. The magnetic field promotes the recovery and recrystallization and leads to much lower hardness at 150?250 °C, while it can suppress the abnormal grain growth and form more homogeneous grain size distributions annealed at 300?400 °C.
文摘High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic field as a field source. It has higher resolution and greater depth penetration than the direct current method and is especially fit for geothermal energy exploration and low- and mid-level groundwater detection. We introduce a successful application of high-frequency electromagnetic sounding for evaluating geothermal water resources. The high frequency electromagnetic system (MT-USA with a frequency range from 10 KHz to 1 Hz) is first applied to sample field data from China. A remote reference station is used to assure sampled data quality. We then perform 2D inversion image processing with the electrical method data. The results basically indicate the spatial distribution of underground geothermal water and provide favorable clues to finding the sources of the subsurface geothermal water in this area.
基金Project(2012-RIAIB300784) supported by Basic Science Research Program through the NRF of Korea funded by the MESTProject(2012HIB8A2026212) supported by the MEST and NRF of Korea the Human Training Project for Regional Innovation
文摘The effect of sintering temperature on the structure, magnetic transition and magnetic entropy of La0.6Ca0.4MnO3 manganite was studied. It was observed that this compound belongs to the orthorhombic structure with the Pnma space group without any impurity phase. The effect of sintering temperature on the Curie temperature(TC) was studied. The small increment in TC is found with increasing the sintering temperature. The magnetocaloric study exposes a quite large change of the magnetic entropy, which varies with sintering temperature. For an applied magnetic field of 3 T and sintering temperature of 1300 °C, the relative cooling power(RCP) is 89 J/kg. As a result, the studied compound can be considered as potential material for magnetic refrigeration near and below room temperature.
基金Project(51276154)supported by the National Natural Science Foundation of ChinaProject(2012010111014)supported by the University Doctoral Subject Special Foundation of China
文摘The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu_2(CeCu_2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of HoCu_2 were a mixture of Cu, unknown hydride Ⅰ, and unknown hydride Ⅱ. Based on the PCT(pressure-concentration-temperature) curves under different reaction temperatures, the relationships among reaction temperature, equilibrium pressure, and maximum hydrogen absorption capacity were analyzed and discussed. The enthalpy change ΔH and entropy change ΔS as a result of the whole hydrogenation process were also calculated from the PCT curves. The magnetization and volumetric specific heat capacity of the hydride were also measured by SQUID magnetometer and PPMS, respectively.
基金Supported by the National Natural Science Foundation of China(61601227)the Natural Science Foundation of Jiangsu Province(BK20160939)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(16KJB180010)the Qing Lan Project and Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A novel magnetic adsorbent was synthesized by magnetizing bentonite by APTES-Fe_3O_4 via a functional groupbridged interaction. The characterization of APTES-Fe_3O_4/bentonite was conducted via transmission electron microscope(TEM), X-ray diffraction(XRD), Fourier transform infrared spectrophotometer(FT-IR), thermal gravimetric analysis(TGA), vibrating sample magnetometer(VSM), zeta potential analysis and Brunner–Emmet–Teller(BET). The APTES-Fe_3O_4/bentonite was assessed as adsorbents for methylene blue(MB) with a high adsorption capacity(91.83 mg·g^(-1)). Factors affecting the adsorption of MB(such as p H, equilibrium time, temperature and initial concentration) were investigated. The adsorption process completely reaches equilibrium after 120 min and the maximum sorption is achieved at p H 8.0. The adsorption trend follows the pseudosecond order kinetics model. The adsorption data gives good fits with Langmuir isotherm model. The parameter factor RLfalls between 0 and 1, indicating the adsorption of MB is favorable. The adsorption process is endothermic with positive ΔH^0 values. The positive values of ΔG^0 confirm the affinity of the adsorbent towards MB, and suggest an increased randomness at the solid–liquid interface during the adsorption process. Regeneration of the saturated adsorbent was easily carried out via gamma-irradiation.
基金Supported by the National Science Foundation of China(Nos.21566029,21566028and 21266017)
文摘The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier transform infrared spectroscopy (FTIR), and H20 adsorption mechanism on the surface of lignite pyrolysis was inferred. Two major changes in the pore structure of lignite char were observed as temperature increased in 105-200 ℃ and 500-700 ℃. Pyrolysis temperature is a significant factor in removing carboxyl and phenolic hydroxyl from lignite. Variation of ether bond content can be divided into three stages; the content initially increased, then decreased, and finally increased. The equilibrium adsorption ratio, content of oxygen-containing groups, and variation of pore volume below 700° were closely correlated with each other. The amount of adsorbed water on char pyrolyzed at 700 ℃ increased. Moreover, the adsorption capacity of the lignite decreased, and the adsorption state changed.
文摘A repulsive vortex\|vortex interaction model was used to numerically study the melting transition of the two\|dimensional vortex system with Monte Carlo method. Then a δ\|function\|like peak in the specific heat was observed and the internal energy showed a sharp drop at the melting temperature, which indicated that there exists a first\|order melting transition at finite temperatures. The Lindemann criterion was also investigated and valid, but different from previous simulation results.
文摘The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of (E)-13-ocimene. Myrrh was extracted with hexane to avoid inducing changes in the constituents and odor. The main constituent, (E)-L3-ocimene (group A; low boiling point), and the other constituents (group B; high boiling point) of the hexane extract were separated by bulb-to-bulb distillation. The constituents of groups A and B were analyzed over time by nuclear magnetic resonance analysis and the odors were evaluated. Myrrh's odor depended on both the amount of thermally unstable (E)-[3-ocimene, which contributed to the fresh odor, and the constituents of group B (thermally stable), which contributed to the myrrh-like odor. Six compounds (c^-santalene, (Z)-a-bisabolene, c^-bergamotene, (E)-ct-santalal, c^-photosantalol and campherenol) were isolated from group B. No individual group B component had a myrrh-like odor, although the combined odor of group B was myrrh like. The authors demonstrated that the aroma profile of myrrh depends on the thermal instability of (E)-^-ocimene and a combination of six thermally stable terpenes with similar molecular structures.