Going to the movies has become an expensive and often annoying activity.In some parts of the country,movie-goers are paying as much as＄10.50 a ticket. Multiply that times two if you take a friend;then add in popcorn ...Going to the movies has become an expensive and often annoying activity.In some parts of the country,movie-goers are paying as much as＄10.50 a ticket. Multiply that times two if you take a friend;then add in popcorn and soda,and maybe some chocolate covered raisins,too---they are"nature’s candy"---and you’re＄40 the poorer.展开更多
The supercritical CO_(2)cOoled Lithium-Lead(COOL)blanket has been designed as one advanced blanket candidate for the Chinese Fusion Engineering Test Reactor(CFETR).This work focuses on the electromagnetic(EM)loads(Max...The supercritical CO_(2)cOoled Lithium-Lead(COOL)blanket has been designed as one advanced blanket candidate for the Chinese Fusion Engineering Test Reactor(CFETR).This work focuses on the electromagnetic(EM)loads(Maxwell force and Lorentz force)acting on the COOL blanket,which are important mechanical loads in further structural analysis of the COOL blanket.A 3D electromagnetic analysis is performed using the ANSYS finite element method to obtain EM loads on the COOL blanket in this study.At first,the magnetic scalar potential(MSP)method is used to obtain the magnetic field and the Maxwell force on the COOL blanket.Then,the magnetic vector potential(MVP)method is performed during a plasma disruption event to get the eddy current distribution.At last,a multi-step method is adopted for the calculation of the Lorentz force and the torque.The maximum Lorentz forces of inboard and outboard blanket structural components are 5624 kN and 2360 kN respectively.展开更多
Objective:Patients who are involuntarily committed to a psychiatric facility often experience anxiety or increased anxiety in response to being placed in the institutional environment.The weighted blanket introduced a...Objective:Patients who are involuntarily committed to a psychiatric facility often experience anxiety or increased anxiety in response to being placed in the institutional environment.The weighted blanket introduced a proactive treatment option.The purpose of this study was to evaluate patients’anxiety symptoms before and after weighted blanket,compared to a group that did not use a weighted blanket to control anxiety.Methods:This study was conducted in an inpatient mental health facility from June 10,2019,through November 7,2019,with psychiatric patients who were not actively psychotic.Participants were offered the choice of weighted or unweighted blankets for a 20-minute intervention.The treatment group was comprised of individuals who had opted to use a 14-pound weighted blanket,20-pound weighted blanket or 5-pound weighted lap pad.Participants in the comparison group were active in a wider range of settings.Before application of the blankets,pulse rate was measured using a pulse oximeter,and anxiety was measured using the Spielberger State-Trait Anxiety Inventory shortened form(STAI:Y-6).Both measures were taken again after the intervention.A two-way mixed analysis of variance(ANOVA)was run to examine the interaction effects between time(pre/post)and group(comparison/weighted blanket).Simple main effects were then further examined for the comparison/weighted blanket groups using a repeated measures ANOVA.Within the weighted blanket group,additional two-way mixed ANOVA was run to determine if gender or blanket weight made a statistically significant difference.Results:There was a statistically significant difference(P<0.05)among those who used weighted blankets(n=61)and those who did not(n=61)based on the pre/post data for both the STAI:Y-6 inventory and the patients’pulse rates.The results of two-way ANOVA indicated a significant interaction effect between intervention time and group(P<0.001).Repeated measures ANOVA indicated a change between pre/post for the weighted blanket group only,and showed significant reductions in both the STAI:Y-6(P<0.001)and pulse rates(P=0.040).Within the weighted blanket group,additional two-way mixed ANOVA showed that neither gender nor blanket weight had significant difference for either the STAI:Y-6 or the pulse measures.Conclusion:The use of weighted blankets is a safe and potentially effective way to help individuals in a psychiatric facility manage anxiety.This study found a statistically significant drop in anxiety for adults at an inpatient facility,as shown by the STAI:Y-6 scores and drop in pulse rates among patients using weighted blankets.This study suggests a possible alternative to medications,seclusion and physical restraints,which are not patient-centered or trauma-supported.展开更多
Gamma-emitting radionuclide ^(99m)Tc is globally used for the diagnosis of various pathological conditions owing to its ideal single-photon emission computed tomography (SPECT) characteristics.However,the short half-l...Gamma-emitting radionuclide ^(99m)Tc is globally used for the diagnosis of various pathological conditions owing to its ideal single-photon emission computed tomography (SPECT) characteristics.However,the short half-life of ^(99m)Tc (T_(1/2)=6 h)makes it difficult to store or transport.Thus,the production of ^(99m)Tc is tied to its parent radionuclide ^(99)Mo (T_(1/2)=66 h).The major production paths are based on accelerators and research reactors.The reactor process presents the potential for nuclear proliferation owing to its use of highly enriched uranium (HEU).Accelerator-based methods tend to use deuterium–tritium(D–T) neutron sources but are hindered by the high cost of tritium and its challenging operation.In this study,a new ^(99)Mo production design was developed based on a deuterium–deuterium (D–D) gas dynamic trap fusion neutron source (GDT-FNS) and a subcritical blanket system (SBS) assembly with a low-enriched uranium (LEU) solution.GDT-FNS can provide a relatively high-neutron intensity,which is one of the advantages of ^(99)Mo production.We provide a Monte Carlo-based neutronics analysis covering the calculation of the subcritical multiplication factor (k_(s)) of the SBS,optimization design for the reflector,shielding layer,and ^(99)Mo production capacity.Other calculations,including the neutron flux and nuclear heating distributions,are also provided for an overall evaluation of the production system.The results demonstrated that the SBS meets the nuclear critical safety design requirement (k_(s)<0.97) and maintained a high ^(99)Mo production capacity.The proposed system can generate approximately 157 Ci ^(99)Mo for a stable 24 h operation with a neutron intensity of 1×10^(14) n/s,which can meet 50%of China’s demand in 2025.展开更多
The netted radar system(NRS)has been proved to possess unique advantages in anti-jamming and improving target tracking performance.Effective resource management can greatly ensure the combat capability of the NRS.In t...The netted radar system(NRS)has been proved to possess unique advantages in anti-jamming and improving target tracking performance.Effective resource management can greatly ensure the combat capability of the NRS.In this paper,based on the netted collocated multiple input multiple output(CMIMO)radar,an effective joint target assignment and power allocation(JTAPA)strategy for tracking multi-targets under self-defense blanket jamming is proposed.An architecture based on the distributed fusion is used in the radar network to estimate target state parameters.By deriving the predicted conditional Cramer-Rao lower bound(PC-CRLB)based on the obtained state estimation information,the objective function is formulated.To maximize the worst case tracking accuracy,the proposed JTAPA strategy implements an online target assignment and power allocation of all active nodes,subject to some resource constraints.Since the formulated JTAPA is non-convex,we propose an efficient two-step solution strategy.In terms of the simulation results,the proposed algorithm can effectively improve tracking performance in the worst case.展开更多
25.birthplace(名词) 该词的意思是“诞生地,出生地”。英语的释义是site of origin;place where somebody is born。Coriolanus(《科里奥兰纳斯》)于大约1608 年完成,1623年用对开本印刷,按创作顺序排列, 大概是莎士比亚的最后一部悲剧。
The water-cooled ceramic breeder (WCCB) blanket is one of the blanket candidates for Chinese fusion engineering testing reactor (CFETR) and is being developed at the Institute of Plasma Physics, Chinese Academy of Sci...The water-cooled ceramic breeder (WCCB) blanket is one of the blanket candidates for Chinese fusion engineering testing reactor (CFETR) and is being developed at the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). This paper reviews design and evolution of the WCCB blanket for CFETR, and presents a new WCCB blanket design according to the latest CFETR core parameters (major and minor radii are R = 7.2 m and a = 2.2 m, respectively) and missions. This new design is expected to satisfy multiple CFETR operation modes of 0.2, 0.5, 1.0, and 1.5 GW fusion power and achieve tritium self-sufficiency. The feasibility of the updated blanket design is evaluated from the aspects of neutronics and thermo-hydraulics. Furthermore, the research and development (R&D) activities supporting to the WCCB blanket for CFETR are reported, including the design code, the water loop experiments, the pebble bed modeling and experiments, and the components fabrication technology.展开更多
This paper addresses the existence detection of blanket jamming based on fractal features in fractional Fourier transform （FRET） domain. Firstly, the existences of fractal features of three typical jamming signals a...This paper addresses the existence detection of blanket jamming based on fractal features in fractional Fourier transform （FRET） domain. Firstly, the existences of fractal features of three typical jamming signals are analyzed, and box dimension and information dimension are employed to describe fractal features quantitatively. Then the differences of fractal characteristics between blanket jamming and white Gaussian noise （WGN） in FRFT domain are described, and a detector to detect the jamming is proposed. At last, simulations are done to verify that the algorithm is effective preferable.展开更多
In the core of a molten salt fast reactor(MSFR),heavy metal fuel and fission products can be dissolved in a molten fluoride salt to form a eutectic mixture that acts as both fuel and coolant.Fission energy is released...In the core of a molten salt fast reactor(MSFR),heavy metal fuel and fission products can be dissolved in a molten fluoride salt to form a eutectic mixture that acts as both fuel and coolant.Fission energy is released from the fuel salt and transferred to the second loop by fuel salt circulation.Therefore,the MSFR is characterized by strong interaction between the neutronics and the thermal hydraulics.Moreover,recirculation flow occurs,and nuclear heat is accumulated near the fertile blanket,which significantly affects both the flow and the temperature fields in the core.In this work,to further optimize the conceptual geometric design of the MSFR,three geometries of the core and fertile blanket are proposed,and the thermal-hydraulic characteristics,including the three-dimensional flow and temperature fields of the fuel and fertile salts,are simulated and analyzed using a coupling scheme between the open source codes OpenMC and OpenFOAM.The numerical results indicate that a flatter core temperature distribution can be obtained and the hot spot and flow stagnation zones that appear in the upper and lower parts of the core center near the reflector can be eliminated by curving both the top and bottom walls of the core.Moreover,eight cooling loops with a total flow rate of0.0555 m3 s-1 ensur an acceptable temperature distribusure an acceptable temperature distribution in the fertile blanket.展开更多
For the solid blanket concept of helium cooled ceramic breeder (HCCB) demonstration fusion power plant (DEMO), a feasible blanket structure with configuration 2×X is proposed as considering relatively low tempera...For the solid blanket concept of helium cooled ceramic breeder (HCCB) demonstration fusion power plant (DEMO), a feasible blanket structure with configuration 2×X is proposed as considering relatively low temperature limit of neutron multiplier beryllium pebbles. Based on that, preliminary design for the typical blanket module of HCCB DEMO has been carried out and verified by thermal-hydraulic analysis and structural analysis. Furthermore, the specific relationship of maximum temperature depended on the surface heating of blanket key part first wall (FW) is also analyzed.展开更多
Direct simulation of 3-D MHD(magnetohydrodynamics) flows in liquid metal fusion blanket with flow channel insert(FCI) has been conducted.Two kinds of pressure equilibrium slot (PES) in FCI,which are used to balance th...Direct simulation of 3-D MHD(magnetohydrodynamics) flows in liquid metal fusion blanket with flow channel insert(FCI) has been conducted.Two kinds of pressure equilibrium slot (PES) in FCI,which are used to balance the pressure difference between the inside and outside of FCI,are considered with a slot in Hartmann wall or a slot in side wall,respectively.The velocity and pressure distribution of FCI made of SiC/SiC_f are numerically studied to illustrate the 3-D MHD flow effects,which clearly show that t...展开更多
Feature selection plays an important role in data mining and recognition, especially in the large scale text, image and biological data. Specifically, the class label information is unavailable to guide the selection ...Feature selection plays an important role in data mining and recognition, especially in the large scale text, image and biological data. Specifically, the class label information is unavailable to guide the selection of minimal feature subset in unsupervised feature selection, which is challenging and interesting. An unsupervised feature selection based on Markov blanket and particle swarm optimization is proposed named as UFSMB-PSO. The proposed method seeks to find the high-quality feature subset through multi-particles' cooperation of particle swarm optimization without using any learning algorithms. Moreover, the features' relevance will be computed based on an information metric of relevance gain,which provides an information theoretical foundation for finding the minimization of the redundancy between features. Our results on several benchmark datasets demonstrate that UFSMB-PSO can achieve significant improvement over state of the art unsupervised methods.展开更多
The water-cooled ceramic breeder(WCCB) blanket is one of the three candidates of China's Fusion Engineering Test Reactor(CFETR). The evaluation of the radioactivity and decay heat produced by neutrons for the in-v...The water-cooled ceramic breeder(WCCB) blanket is one of the three candidates of China's Fusion Engineering Test Reactor(CFETR). The evaluation of the radioactivity and decay heat produced by neutrons for the in-vacuum vessel components is essential for the assessment of radioactive wastes and the safety of CFETR. The activation calculation of CFETR in-vacuum vessel components was carried out by using the Monte Carlo N-Particle Transport Code MCNP, IAEA Fusion Evaluated Nuclear Data Library FENDL2.1, and the nuclear inventory code FISPACT-2007 and corresponding EAF-2007 libraries. In these analyses, the three-dimensional(3-D) neutronics model was employed and the WCCB blanket, the divertor, and the shield were modeled in detail to provide the detailed spatial distribution of the neutron flux and energy spectra. Then the neutron flux, energy spectra and the materials specification were transferred to FISPACT for the activation calculation with an assumed irradiation scenario of CFETR. This paper presents the main results of the activation analysis to evaluate the radioactivity, the decay heat, the contact dose, and the waste classification of the radioactive materials. At the time of shutdown, the activity of the WCCB blanket is 1.88×10^(19)Bq and the specific activity, the decay heat and the contact dose rate are 1.7×10^(13)Bq/kg, 3.05 MW, and 2.0×10~3Sv/h respectively. After cooling for 100 years, 79%(4166.4 tons) radioactive wastes produced from the blanket, divertor,high temperature shield(HTS) and low temperature shield(LTS) need near surface disposal, while21%(1112.3 tons) need geological disposal. According to results of the contact dose rate, all the components of the blanket, divertor, HTS and LTS could potentially be recycled after shutdown by using advanced remote handling equipment. In addition, the selection of Eurofer97 or RAFM for the divertor is better than that of SS316 because SS316 makes the activity of the divertor-body keep at a relatively high level.展开更多
In this paper,we consider the scenario of using unmanned aerial vehicles base stations(UAV-BSs)to serve cellular users.In particular,we focus on frnding the minimum number of UAV-BSs as well as their deployment.We pro...In this paper,we consider the scenario of using unmanned aerial vehicles base stations(UAV-BSs)to serve cellular users.In particular,we focus on frnding the minimum number of UAV-BSs as well as their deployment.We propose an optimization model which minimizes the number of UAV-BSs and optimize their positions such that the user equipment(UE)covered ratio is no less than the expectation of network suppliers,the UEs receive acceptable downlink rates,and the UAV-BSs can work in a sustainable manner.We show the NP-hardness of this problem and then propose a method to address it.The method first estimates the range of the number of UAV-BSs and then converts the original problem to one which maximizes the UE served ratio,given the number of UAV-BSs within that range.We present a maximizing algorithm to solve it with the proof of convergence.Extensive simulations based on a realistic dataset have been conducted to demonstrate the effectiveness of the proposed method.展开更多
文摘Going to the movies has become an expensive and often annoying activity.In some parts of the country,movie-goers are paying as much as＄10.50 a ticket. Multiply that times two if you take a friend;then add in popcorn and soda,and maybe some chocolate covered raisins,too---they are"nature’s candy"---and you’re＄40 the poorer.
基金supported by the Comprehensive Research Facility for Fusion Technology(CRAFT)Program of China(No.2018-000052-73-01-001228)National Natural Science Foundation of China(No.12205330)。
文摘The supercritical CO_(2)cOoled Lithium-Lead(COOL)blanket has been designed as one advanced blanket candidate for the Chinese Fusion Engineering Test Reactor(CFETR).This work focuses on the electromagnetic(EM)loads(Maxwell force and Lorentz force)acting on the COOL blanket,which are important mechanical loads in further structural analysis of the COOL blanket.A 3D electromagnetic analysis is performed using the ANSYS finite element method to obtain EM loads on the COOL blanket in this study.At first,the magnetic scalar potential(MSP)method is used to obtain the magnetic field and the Maxwell force on the COOL blanket.Then,the magnetic vector potential(MVP)method is performed during a plasma disruption event to get the eddy current distribution.At last,a multi-step method is adopted for the calculation of the Lorentz force and the torque.The maximum Lorentz forces of inboard and outboard blanket structural components are 5624 kN and 2360 kN respectively.
基金Oglethorpe,Inc.provided partial funding to conduct the study。
文摘Objective:Patients who are involuntarily committed to a psychiatric facility often experience anxiety or increased anxiety in response to being placed in the institutional environment.The weighted blanket introduced a proactive treatment option.The purpose of this study was to evaluate patients’anxiety symptoms before and after weighted blanket,compared to a group that did not use a weighted blanket to control anxiety.Methods:This study was conducted in an inpatient mental health facility from June 10,2019,through November 7,2019,with psychiatric patients who were not actively psychotic.Participants were offered the choice of weighted or unweighted blankets for a 20-minute intervention.The treatment group was comprised of individuals who had opted to use a 14-pound weighted blanket,20-pound weighted blanket or 5-pound weighted lap pad.Participants in the comparison group were active in a wider range of settings.Before application of the blankets,pulse rate was measured using a pulse oximeter,and anxiety was measured using the Spielberger State-Trait Anxiety Inventory shortened form(STAI:Y-6).Both measures were taken again after the intervention.A two-way mixed analysis of variance(ANOVA)was run to examine the interaction effects between time(pre/post)and group(comparison/weighted blanket).Simple main effects were then further examined for the comparison/weighted blanket groups using a repeated measures ANOVA.Within the weighted blanket group,additional two-way mixed ANOVA was run to determine if gender or blanket weight made a statistically significant difference.Results:There was a statistically significant difference(P<0.05)among those who used weighted blankets(n=61)and those who did not(n=61)based on the pre/post data for both the STAI:Y-6 inventory and the patients’pulse rates.The results of two-way ANOVA indicated a significant interaction effect between intervention time and group(P<0.001).Repeated measures ANOVA indicated a change between pre/post for the weighted blanket group only,and showed significant reductions in both the STAI:Y-6(P<0.001)and pulse rates(P=0.040).Within the weighted blanket group,additional two-way mixed ANOVA showed that neither gender nor blanket weight had significant difference for either the STAI:Y-6 or the pulse measures.Conclusion:The use of weighted blankets is a safe and potentially effective way to help individuals in a psychiatric facility manage anxiety.This study found a statistically significant drop in anxiety for adults at an inpatient facility,as shown by the STAI:Y-6 scores and drop in pulse rates among patients using weighted blankets.This study suggests a possible alternative to medications,seclusion and physical restraints,which are not patient-centered or trauma-supported.
基金supported by Anhui Provincial Key R&D Program (202104g0102007)Hefei Municipal Natural Science Foundation (2022011)+2 种基金Collaborative Innovation Program of Hefei Science CenterChinese Academy of Sciences(2022HSC CIP024)International Partnership Program of Chinese Academy of Sciences (116134KYSB20200001)。
文摘Gamma-emitting radionuclide ^(99m)Tc is globally used for the diagnosis of various pathological conditions owing to its ideal single-photon emission computed tomography (SPECT) characteristics.However,the short half-life of ^(99m)Tc (T_(1/2)=6 h)makes it difficult to store or transport.Thus,the production of ^(99m)Tc is tied to its parent radionuclide ^(99)Mo (T_(1/2)=66 h).The major production paths are based on accelerators and research reactors.The reactor process presents the potential for nuclear proliferation owing to its use of highly enriched uranium (HEU).Accelerator-based methods tend to use deuterium–tritium(D–T) neutron sources but are hindered by the high cost of tritium and its challenging operation.In this study,a new ^(99)Mo production design was developed based on a deuterium–deuterium (D–D) gas dynamic trap fusion neutron source (GDT-FNS) and a subcritical blanket system (SBS) assembly with a low-enriched uranium (LEU) solution.GDT-FNS can provide a relatively high-neutron intensity,which is one of the advantages of ^(99)Mo production.We provide a Monte Carlo-based neutronics analysis covering the calculation of the subcritical multiplication factor (k_(s)) of the SBS,optimization design for the reflector,shielding layer,and ^(99)Mo production capacity.Other calculations,including the neutron flux and nuclear heating distributions,are also provided for an overall evaluation of the production system.The results demonstrated that the SBS meets the nuclear critical safety design requirement (k_(s)<0.97) and maintained a high ^(99)Mo production capacity.The proposed system can generate approximately 157 Ci ^(99)Mo for a stable 24 h operation with a neutron intensity of 1×10^(14) n/s,which can meet 50%of China’s demand in 2025.
基金National Natural Science Foundation of China(Grant No.62001506)to provide fund for conducting experiments。
文摘The netted radar system(NRS)has been proved to possess unique advantages in anti-jamming and improving target tracking performance.Effective resource management can greatly ensure the combat capability of the NRS.In this paper,based on the netted collocated multiple input multiple output(CMIMO)radar,an effective joint target assignment and power allocation(JTAPA)strategy for tracking multi-targets under self-defense blanket jamming is proposed.An architecture based on the distributed fusion is used in the radar network to estimate target state parameters.By deriving the predicted conditional Cramer-Rao lower bound(PC-CRLB)based on the obtained state estimation information,the objective function is formulated.To maximize the worst case tracking accuracy,the proposed JTAPA strategy implements an online target assignment and power allocation of all active nodes,subject to some resource constraints.Since the formulated JTAPA is non-convex,we propose an efficient two-step solution strategy.In terms of the simulation results,the proposed algorithm can effectively improve tracking performance in the worst case.
文摘25.birthplace(名词) 该词的意思是“诞生地,出生地”。英语的释义是site of origin;place where somebody is born。Coriolanus(《科里奥兰纳斯》)于大约1608 年完成,1623年用对开本印刷,按创作顺序排列, 大概是莎士比亚的最后一部悲剧。
基金the financial support of the National Key R&D Program of China(Grants2017YFE0300503 and 2017YFE0300604)the National Natural Science Foundation of China(Grant 11775256)
文摘The water-cooled ceramic breeder (WCCB) blanket is one of the blanket candidates for Chinese fusion engineering testing reactor (CFETR) and is being developed at the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). This paper reviews design and evolution of the WCCB blanket for CFETR, and presents a new WCCB blanket design according to the latest CFETR core parameters (major and minor radii are R = 7.2 m and a = 2.2 m, respectively) and missions. This new design is expected to satisfy multiple CFETR operation modes of 0.2, 0.5, 1.0, and 1.5 GW fusion power and achieve tritium self-sufficiency. The feasibility of the updated blanket design is evaluated from the aspects of neutronics and thermo-hydraulics. Furthermore, the research and development (R&D) activities supporting to the WCCB blanket for CFETR are reported, including the design code, the water loop experiments, the pebble bed modeling and experiments, and the components fabrication technology.
文摘This paper addresses the existence detection of blanket jamming based on fractal features in fractional Fourier transform （FRET） domain. Firstly, the existences of fractal features of three typical jamming signals are analyzed, and box dimension and information dimension are employed to describe fractal features quantitatively. Then the differences of fractal characteristics between blanket jamming and white Gaussian noise （WGN） in FRFT domain are described, and a detector to detect the jamming is proposed. At last, simulations are done to verify that the algorithm is effective preferable.
基金supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)the Frontier Science Key Program of the Chinese Academy of Sciences(No.QYZDY-SSW-JSC016)。
文摘In the core of a molten salt fast reactor(MSFR),heavy metal fuel and fission products can be dissolved in a molten fluoride salt to form a eutectic mixture that acts as both fuel and coolant.Fission energy is released from the fuel salt and transferred to the second loop by fuel salt circulation.Therefore,the MSFR is characterized by strong interaction between the neutronics and the thermal hydraulics.Moreover,recirculation flow occurs,and nuclear heat is accumulated near the fertile blanket,which significantly affects both the flow and the temperature fields in the core.In this work,to further optimize the conceptual geometric design of the MSFR,three geometries of the core and fertile blanket are proposed,and the thermal-hydraulic characteristics,including the three-dimensional flow and temperature fields of the fuel and fertile salts,are simulated and analyzed using a coupling scheme between the open source codes OpenMC and OpenFOAM.The numerical results indicate that a flatter core temperature distribution can be obtained and the hot spot and flow stagnation zones that appear in the upper and lower parts of the core center near the reflector can be eliminated by curving both the top and bottom walls of the core.Moreover,eight cooling loops with a total flow rate of0.0555 m3 s-1 ensur an acceptable temperature distribusure an acceptable temperature distribution in the fertile blanket.
基金supported by the National Special Project of China for magnetic confined nuclear fusion energy(2015GB108004)
文摘For the solid blanket concept of helium cooled ceramic breeder (HCCB) demonstration fusion power plant (DEMO), a feasible blanket structure with configuration 2×X is proposed as considering relatively low temperature limit of neutron multiplier beryllium pebbles. Based on that, preliminary design for the typical blanket module of HCCB DEMO has been carried out and verified by thermal-hydraulic analysis and structural analysis. Furthermore, the specific relationship of maximum temperature depended on the surface heating of blanket key part first wall (FW) is also analyzed.
基金supported by National Natural Science Foundation of China with grant Nos.10872212,50936006National Magnetic Confinement Fusion Science Program in China with grant No.2009GB10401
文摘Direct simulation of 3-D MHD(magnetohydrodynamics) flows in liquid metal fusion blanket with flow channel insert(FCI) has been conducted.Two kinds of pressure equilibrium slot (PES) in FCI,which are used to balance the pressure difference between the inside and outside of FCI,are considered with a slot in Hartmann wall or a slot in side wall,respectively.The velocity and pressure distribution of FCI made of SiC/SiC_f are numerically studied to illustrate the 3-D MHD flow effects,which clearly show that t...
基金supported by the National Natural Science Foundation of China(6113900261501229+1 种基金11547040)the Guangdong Natural Science Foundation(2016A030310051)
文摘Feature selection plays an important role in data mining and recognition, especially in the large scale text, image and biological data. Specifically, the class label information is unavailable to guide the selection of minimal feature subset in unsupervised feature selection, which is challenging and interesting. An unsupervised feature selection based on Markov blanket and particle swarm optimization is proposed named as UFSMB-PSO. The proposed method seeks to find the high-quality feature subset through multi-particles' cooperation of particle swarm optimization without using any learning algorithms. Moreover, the features' relevance will be computed based on an information metric of relevance gain,which provides an information theoretical foundation for finding the minimization of the redundancy between features. Our results on several benchmark datasets demonstrate that UFSMB-PSO can achieve significant improvement over state of the art unsupervised methods.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB108004,2015BG108002,2014GB122000,2014GB119000)National Natural Science Foundation of China(No.11175207)
文摘The water-cooled ceramic breeder(WCCB) blanket is one of the three candidates of China's Fusion Engineering Test Reactor(CFETR). The evaluation of the radioactivity and decay heat produced by neutrons for the in-vacuum vessel components is essential for the assessment of radioactive wastes and the safety of CFETR. The activation calculation of CFETR in-vacuum vessel components was carried out by using the Monte Carlo N-Particle Transport Code MCNP, IAEA Fusion Evaluated Nuclear Data Library FENDL2.1, and the nuclear inventory code FISPACT-2007 and corresponding EAF-2007 libraries. In these analyses, the three-dimensional(3-D) neutronics model was employed and the WCCB blanket, the divertor, and the shield were modeled in detail to provide the detailed spatial distribution of the neutron flux and energy spectra. Then the neutron flux, energy spectra and the materials specification were transferred to FISPACT for the activation calculation with an assumed irradiation scenario of CFETR. This paper presents the main results of the activation analysis to evaluate the radioactivity, the decay heat, the contact dose, and the waste classification of the radioactive materials. At the time of shutdown, the activity of the WCCB blanket is 1.88×10^(19)Bq and the specific activity, the decay heat and the contact dose rate are 1.7×10^(13)Bq/kg, 3.05 MW, and 2.0×10~3Sv/h respectively. After cooling for 100 years, 79%(4166.4 tons) radioactive wastes produced from the blanket, divertor,high temperature shield(HTS) and low temperature shield(LTS) need near surface disposal, while21%(1112.3 tons) need geological disposal. According to results of the contact dose rate, all the components of the blanket, divertor, HTS and LTS could potentially be recycled after shutdown by using advanced remote handling equipment. In addition, the selection of Eurofer97 or RAFM for the divertor is better than that of SS316 because SS316 makes the activity of the divertor-body keep at a relatively high level.
基金supported by the National Natural Science Foundation of China(61903076,61773109)Liaoning Revitalization Talents Program(XLYC1807009)
文摘In this paper,we consider the scenario of using unmanned aerial vehicles base stations(UAV-BSs)to serve cellular users.In particular,we focus on frnding the minimum number of UAV-BSs as well as their deployment.We propose an optimization model which minimizes the number of UAV-BSs and optimize their positions such that the user equipment(UE)covered ratio is no less than the expectation of network suppliers,the UEs receive acceptable downlink rates,and the UAV-BSs can work in a sustainable manner.We show the NP-hardness of this problem and then propose a method to address it.The method first estimates the range of the number of UAV-BSs and then converts the original problem to one which maximizes the UE served ratio,given the number of UAV-BSs within that range.We present a maximizing algorithm to solve it with the proof of convergence.Extensive simulations based on a realistic dataset have been conducted to demonstrate the effectiveness of the proposed method.
