Two water cooled toroidal limiters were used in HT-7 to exhaust power effectively since the spring campaign of 2004. The heat flux deposition pattern on their surfaces both in steady state and transient state, caused ...Two water cooled toroidal limiters were used in HT-7 to exhaust power effectively since the spring campaign of 2004. The heat flux deposition pattern on their surfaces both in steady state and transient state, caused only by plasma displacement, were studied with ANSYS code. The ripple of the toroidal magnetic field was taken into account. The heat flux deposition appeared to be periodic. The ripple and the relative location of the limiter to the toroidal field (TF) coils, as well as the shift of the center of the last closed flux surface (LCFS), had a vital influence upon the heat flux profile. The location with maximum temperature didn't coincide with that for the maximum heat flux in a transient state. The shift of the center of LCFS, caused by plasma displacement, made the heat flux on the limiter more uneven. The heat flux deposition pattern concerning the real shift of the center of LCFS at a transient state calls for further research.展开更多
The heat flux deposition pattern on the toroidal limiters installed in HT-7 was simulated with ANSYS code. The simulation model was established with the ripple of the magnetic field. The heat deposition pattern and te...The heat flux deposition pattern on the toroidal limiters installed in HT-7 was simulated with ANSYS code. The simulation model was established with the ripple of the magnetic field. The heat deposition pattern and temperature distribution on the surface of the toroidal linfiters were obtained. A comparison of the results obtained with and without the shaped tiles, used to reduce the heat flux on the leading edge of the limiters, was made. The maximum heat load allowed at the leading edge was about 1.8 MW/m2 because of the poor power removing capacity on the ends of the limiters. This approach can also be applied to other devices with a limiter configuration in a circular cross-section shape.展开更多
A novel heat substrate technique, high frequency inductive heat deposition (IHD), was introduced to coat porous carbon materials, C/C and carbon felt to improve their bioactivity. The morphologies, composition and m...A novel heat substrate technique, high frequency inductive heat deposition (IHD), was introduced to coat porous carbon materials, C/C and carbon felt to improve their bioactivity. The morphologies, composition and microstructure of the resulting coatings were examined by scanning electron microscopy (SEM), energy dispersive spectra (EDS), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). The results show that, the calcium phosphate consisted of non-stoichiometric, CO3-containing and plate- like octacalcium phosphate (Ca8-xH2(PO4)6, OCP) could uniformly cover the entire porous surfaces of carbon materials. Good adhesion of the coating to carbon material substrates was observed.展开更多
A new method of fabricating C/C composite materials, namely electric heating CVD method, was used, which electrified the carbon fiber directly by using the conductivity of itself. Acetylene was used as the carbon sour...A new method of fabricating C/C composite materials, namely electric heating CVD method, was used, which electrified the carbon fiber directly by using the conductivity of itself. Acetylene was used as the carbon source with nitrogen as dilution gas, and the pyrolytic carbon started to deposit on the carbon fiber surface when the deposition temperature was reached. The morphology of pyrolytic carbon was characterized by SEM, and the surface properties of carbon fibers before and after CVD were characterized by Raman spectroscopy. The experimental results show that the electric heating method is a novel method to fabricate C/C composite materials, which can form a dense C/C composite material in a short time. The order degree and the average crystallite size of the carbon fiber surface were decreased after the experiment.展开更多
Sodium beta alumina(Na-β-alumina) films were synthesized by heat treatment of NaAl6O(9.5)and γ-NaA1O2 films at temperatures of 1 373-1 573 K.Single-phase γ-NaA1O2 and NaAl6O(9.5) films were prepared by laser ...Sodium beta alumina(Na-β-alumina) films were synthesized by heat treatment of NaAl6O(9.5)and γ-NaA1O2 films at temperatures of 1 373-1 573 K.Single-phase γ-NaA1O2 and NaAl6O(9.5) films were prepared by laser chemical vapor deposition at the deposition temperatures of 976 and 1 100 K,respectively.Subsequent heat treatment of the films resulted in the formation of Na-β-alumina with α-Al2O3 at temperatures above 1 373 K for NaAl6O(9.5) and 1 473 K for γ-NaA1O2.On heat treatment at temperatures of 1 473-1 573 K,the faceted morphology with terraces of the as-deposited(110)-oriented γ-NaAlO2 films transformed to a porous morphology with platelet grains comprising Na-β-alumina and α-Al2O3.On heat treatment at temperatures of1 373-1 473 K,the pyramidal,faceted grains of as-deposited NaAl6O(9.5) films transformed to planer,shapeanisotropic morphology in the film of mixed Na-β-alumina and α-Al2O3.A dense morphology was observed in both the as-deposited and heat-treated NaAl6O(9.5) films.展开更多
A kicker is a critical component for beam injection and accumulation in circular particle accelerators. A ceramic slat kicker plated with a TiN conductive coating was applied in the Beijing Electron Positron Collider ...A kicker is a critical component for beam injection and accumulation in circular particle accelerators. A ceramic slat kicker plated with a TiN conductive coating was applied in the Beijing Electron Positron Collider (BEPCII). However, the ceramic slat kicker has experienced several sudden malfunctions during the operation of the BEPCII in the past. With a reliable kicker structure, a three-metal-strip kicker can substitute the original ceramic slat kicker to maintain the operational stability of the BEPCII. A comparison of the numerical simulation was conducted for three kicker models, demonstrating the comprehensive advantage of the three-metal-strip kicker. Furthermore, impedance bench measurements were conducted on a prototype of a three-metal-strip kicker. The longitudinal beam-coupling impedance was measured using a vector network analyzer via the coaxial wire method. A satisfactory agreement was obtained between the numerical simulations and measurements. Based on the numerical simulation data, the loss factor was 0.01721 V/pC, and the effective impedance was 3.59 mΩ(σ=10 mm).The simulation of the heat deposition on each part of the kicker demonstrated that 84.4%of the parasitic loss of the beam was deposited on the metal strips, and the total heat deposition power on the kicker was between 113.3 and 131.5 W. The obtained heat deposition powers can be considered as a reference for establishing the cooling system.展开更多
We used the spheroidal beam equation to calculate the sound field created by focusing a transducer with a wide aperture angle to obtain the heat deposition, and then we used the Pennes bioheat equation to calculate th...We used the spheroidal beam equation to calculate the sound field created by focusing a transducer with a wide aperture angle to obtain the heat deposition, and then we used the Pennes bioheat equation to calculate the temperature field in biological tissue with ribs and to ascertain the effects of rib parameters on the temperature field. The results show that the location and the gap width between the ribs have a great influence on the axial and radial temperature rise of multilayer biological tissue. With a decreasing gap width, the location of the maximum temperature rise moves forward; as the ribs are closer to the transducer surface, the sound energy that passes through the gap between the ribs at the focus decreases, the maximum temperature rise decreases, and the location of the maximum temperature rise moves forward with the ribs.展开更多
Three-dimensional photonic crystal (PC) heterostructures with high quality are fabricated by using a pressure controlled isothermal heating vertical deposition technique. The formed heterostructures have higher qual...Three-dimensional photonic crystal (PC) heterostructures with high quality are fabricated by using a pressure controlled isothermal heating vertical deposition technique. The formed heterostructures have higher quality, such as deeper band gaps and sharper band edges, than the heterostructures reported so far. Such a significant improvement in quality is due to the introduction of a thin TiO2 buffer layer between the two constitutional PCs. It is revealed that the disorder caused by lattice mismatch is successfully removed if the buffer layer is used once. As a result, the formed heterostructures possess the main features in the band gap of constitutional PCs. The crucial role of the thin buffer layer is also verified by numerical simulations based on the finite-difference time-domain technique.展开更多
基金supported by National Natural Science Foundation of China (No.10475080)Foundation of Hefei Institutes of Physical Science of China (No.2006 YZJJ-1)
文摘Two water cooled toroidal limiters were used in HT-7 to exhaust power effectively since the spring campaign of 2004. The heat flux deposition pattern on their surfaces both in steady state and transient state, caused only by plasma displacement, were studied with ANSYS code. The ripple of the toroidal magnetic field was taken into account. The heat flux deposition appeared to be periodic. The ripple and the relative location of the limiter to the toroidal field (TF) coils, as well as the shift of the center of the last closed flux surface (LCFS), had a vital influence upon the heat flux profile. The location with maximum temperature didn't coincide with that for the maximum heat flux in a transient state. The shift of the center of LCFS, caused by plasma displacement, made the heat flux on the limiter more uneven. The heat flux deposition pattern concerning the real shift of the center of LCFS at a transient state calls for further research.
基金National Natural Science Foundation of China(No.10475080)the Foundation of Hefei Institutes of Physical Science(No.2006YZJJ-1)
文摘The heat flux deposition pattern on the toroidal limiters installed in HT-7 was simulated with ANSYS code. The simulation model was established with the ripple of the magnetic field. The heat deposition pattern and temperature distribution on the surface of the toroidal linfiters were obtained. A comparison of the results obtained with and without the shaped tiles, used to reduce the heat flux on the leading edge of the limiters, was made. The maximum heat load allowed at the leading edge was about 1.8 MW/m2 because of the poor power removing capacity on the ends of the limiters. This approach can also be applied to other devices with a limiter configuration in a circular cross-section shape.
基金the National Natural Science Foundation of China(No.50702034)the Project 2006033 SZU E/Mthe Project 200629-4XXB SZU R/D
文摘A novel heat substrate technique, high frequency inductive heat deposition (IHD), was introduced to coat porous carbon materials, C/C and carbon felt to improve their bioactivity. The morphologies, composition and microstructure of the resulting coatings were examined by scanning electron microscopy (SEM), energy dispersive spectra (EDS), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). The results show that, the calcium phosphate consisted of non-stoichiometric, CO3-containing and plate- like octacalcium phosphate (Ca8-xH2(PO4)6, OCP) could uniformly cover the entire porous surfaces of carbon materials. Good adhesion of the coating to carbon material substrates was observed.
基金Funded by the National Natural Science Foundation of China(51165006)
文摘A new method of fabricating C/C composite materials, namely electric heating CVD method, was used, which electrified the carbon fiber directly by using the conductivity of itself. Acetylene was used as the carbon source with nitrogen as dilution gas, and the pyrolytic carbon started to deposit on the carbon fiber surface when the deposition temperature was reached. The morphology of pyrolytic carbon was characterized by SEM, and the surface properties of carbon fibers before and after CVD were characterized by Raman spectroscopy. The experimental results show that the electric heating method is a novel method to fabricate C/C composite materials, which can form a dense C/C composite material in a short time. The order degree and the average crystallite size of the carbon fiber surface were decreased after the experiment.
基金Funded by the Ministry of Education,Culture,Sports,Science and Technology,a Grant-in-Aid for Challenging Exploratory Research(No.26560235)the ARCMG–IMR Cooperative Program(No.14G0402)of Tohoku Universitythe China Scholarship Council and the 111 Project(No.B13035)of China
文摘Sodium beta alumina(Na-β-alumina) films were synthesized by heat treatment of NaAl6O(9.5)and γ-NaA1O2 films at temperatures of 1 373-1 573 K.Single-phase γ-NaA1O2 and NaAl6O(9.5) films were prepared by laser chemical vapor deposition at the deposition temperatures of 976 and 1 100 K,respectively.Subsequent heat treatment of the films resulted in the formation of Na-β-alumina with α-Al2O3 at temperatures above 1 373 K for NaAl6O(9.5) and 1 473 K for γ-NaA1O2.On heat treatment at temperatures of 1 473-1 573 K,the faceted morphology with terraces of the as-deposited(110)-oriented γ-NaAlO2 films transformed to a porous morphology with platelet grains comprising Na-β-alumina and α-Al2O3.On heat treatment at temperatures of1 373-1 473 K,the pyramidal,faceted grains of as-deposited NaAl6O(9.5) films transformed to planer,shapeanisotropic morphology in the film of mixed Na-β-alumina and α-Al2O3.A dense morphology was observed in both the as-deposited and heat-treated NaAl6O(9.5) films.
基金supported by the National Natural Science Foundation of China (Nos.Y8113C005C and U1832132)。
文摘A kicker is a critical component for beam injection and accumulation in circular particle accelerators. A ceramic slat kicker plated with a TiN conductive coating was applied in the Beijing Electron Positron Collider (BEPCII). However, the ceramic slat kicker has experienced several sudden malfunctions during the operation of the BEPCII in the past. With a reliable kicker structure, a three-metal-strip kicker can substitute the original ceramic slat kicker to maintain the operational stability of the BEPCII. A comparison of the numerical simulation was conducted for three kicker models, demonstrating the comprehensive advantage of the three-metal-strip kicker. Furthermore, impedance bench measurements were conducted on a prototype of a three-metal-strip kicker. The longitudinal beam-coupling impedance was measured using a vector network analyzer via the coaxial wire method. A satisfactory agreement was obtained between the numerical simulations and measurements. Based on the numerical simulation data, the loss factor was 0.01721 V/pC, and the effective impedance was 3.59 mΩ(σ=10 mm).The simulation of the heat deposition on each part of the kicker demonstrated that 84.4%of the parasitic loss of the beam was deposited on the metal strips, and the total heat deposition power on the kicker was between 113.3 and 131.5 W. The obtained heat deposition powers can be considered as a reference for establishing the cooling system.
基金supported by the National Basic Research Program of China(Grant Nos.2012CB921504 and 2011CB707902)the National Natural Science Foundation of China(Grant No.11274166)+4 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.020414380001)the Fund from State Key Laboratory of AcousticsChinese Academy of Sciences(Grant No.SKLA201401)China Postdoctoral Science Foundation(Grant No.2013M531313)the Priority Academic Program Development of Jiangsu Higher Education Institutions and SRF for ROCS,SEM
文摘We used the spheroidal beam equation to calculate the sound field created by focusing a transducer with a wide aperture angle to obtain the heat deposition, and then we used the Pennes bioheat equation to calculate the temperature field in biological tissue with ribs and to ascertain the effects of rib parameters on the temperature field. The results show that the location and the gap width between the ribs have a great influence on the axial and radial temperature rise of multilayer biological tissue. With a decreasing gap width, the location of the maximum temperature rise moves forward; as the ribs are closer to the transducer surface, the sound energy that passes through the gap between the ribs at the focus decreases, the maximum temperature rise decreases, and the location of the maximum temperature rise moves forward with the ribs.
基金Project supported by the National Natural Science Foundation of China (Grant No 10674051)the Program for Innovative Research Team of the Higher Education of Guangdong Province,China (Grant No 06CXTD005)the Key Program of Extracurricular Research in South China Normal University (SCNU),China (Grant No 08GDKC02)
文摘Three-dimensional photonic crystal (PC) heterostructures with high quality are fabricated by using a pressure controlled isothermal heating vertical deposition technique. The formed heterostructures have higher quality, such as deeper band gaps and sharper band edges, than the heterostructures reported so far. Such a significant improvement in quality is due to the introduction of a thin TiO2 buffer layer between the two constitutional PCs. It is revealed that the disorder caused by lattice mismatch is successfully removed if the buffer layer is used once. As a result, the formed heterostructures possess the main features in the band gap of constitutional PCs. The crucial role of the thin buffer layer is also verified by numerical simulations based on the finite-difference time-domain technique.