The purpose of this study was to evaluate the outcome of patients with unresectable hepatocellular carcinoma(HCC) treated by sequential therapy of transcatheter arterial chemoembolization(TACE),three-dimensional c...The purpose of this study was to evaluate the outcome of patients with unresectable hepatocellular carcinoma(HCC) treated by sequential therapy of transcatheter arterial chemoembolization(TACE),three-dimensional conformal radiotherapy(3-DCRT) and high-intensity focused ultrasound(HIFU).From October,2005 to September,2010,120 patients with unresectable HCC received the sequential treatments of several courses of TACE followed in 2-4 weeks by 3-DCRT and then a single session of HIFU with a curative intent.The median tumor irradiation dose was 40 Gy.Tumor response,toxicity and overall survival rate were analyzed.Clinicopathologic factors affecting the primary technique effectiveness and overall survival rates were investigated by univariate analysis or multivariate analysis.All 120 HCC patients were followed up by the last follow-up time.Among these patients,hepatic toxicities due to treatment were notable in 9 cases.Gastrointestinal bleeding after the overall treatment occurred in 2 cases,leukopenia of grade III was detected in 1 case,radiation-induced liver disease(RILD) was observed in 2 patients,and first-and second-degree skin burn around the HIFU treatment zone were observed in 2 patients and 1 patient,respectively.Among 120 patients,23,83 and 14 cases achieved partial response,stable disease and progressive disease,respectively.The overall survival rates at 1 year,3 years and 5 years were 70%,35% and 15%,respectively,with a median survival time of 26 months.Both Child-Pugh liver function grading and radiation dose were determined to be independent predictors for overall survival revealed by the multivariate analysis.It is concluded that the sequential therapy of TACE,3-DCRT and HIFU is a promising therapeutic regimen for unresectable HCC.展开更多
Three-dimensional(3D)vertical architecture transistors represent an important technological pursuit,which have distinct advantages in device integration density,operation speed,and power consumption.However,the fabric...Three-dimensional(3D)vertical architecture transistors represent an important technological pursuit,which have distinct advantages in device integration density,operation speed,and power consumption.However,the fabrication processes of such 3D devices are complex,especially in the interconnection of electrodes.In this paper,we present a novel method which combines suspended electrodes and focused ion beam(FIB)technology to greatly simplify the electrodes interconnection in 3D devices.Based on this method,we fabricate 3D vertical core-double shell structure transistors with ZnO channel and Al_(2)O_(3) gate-oxide both grown by atomic layer deposition.Suspended top electrodes of vertical architecture could be directly connected to planar electrodes by FIB deposited Pt nanowires,which avoid cumbersome steps in the traditional 3D structure fabrication technology.Both single pillar and arrays devices show well behaved transfer characteristics with an Ion/Ioff current ratio greater than 106 and a low threshold voltage around 0 V.The ON-current of the 2×2 pillars vertical channel transistor was 1.2μA at the gate voltage of 3 V and drain voltage of 2 V,which can be also improved by increasing the number of pillars.Our method for fabricating vertical architecture transistors can be promising for device applications with high integration density and low power consumption.展开更多
An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, clo...An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.展开更多
Ni-rich layered cathodes(LiNi_xCo_yMn_(2)O_(2))have recently drawn much attention due to their high specific capacities.However,the poor rate capability of LiNi_xCo_yMn_(2)O_(2),which is mainly originated from the two...Ni-rich layered cathodes(LiNi_xCo_yMn_(2)O_(2))have recently drawn much attention due to their high specific capacities.However,the poor rate capability of LiNi_xCo_yMn_(2)O_(2),which is mainly originated from the twodimensional diffusion of Li ions in the Li slab and Li^(+)/Ni^(2+)cation mixing that hinder the Li^(+)diffusion,has limited their practical application where high power density is needed.Here we integrated Li_(2)MnO_(3)nanodomains into the layered structure of a typical Ni-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)material,which minimized the Li^(+)/Ni^(2+)cationic disordering,and more importantly,established grain boundaries within the NCM811 matrix,thus providing a three-dimensional diffusion channel for Li ions.Accordingly,an average Li-ion diffusion coefficient(D_(Li+))of the Li_(2)MnO_(3)-integrated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811-I)during charge/discharge was calculated to be approximately 6*10^(-10)cm~2 S^(-1),two times of that in the bare NCM811(3*10^(-10)cm~2 S^(-1)).The capacity delivered by the NCM811-I(154.5 mAh g^(-1))was higher than that of NCM811(141.3 mAh g^(-1))at 2 C,and the capacity retention of NCM811-I increased by 13.6%after100 cycles at 0.1 C and 13.4%after 500 cycles at 1 C compared to NCM811.This work provides a valuable routine to improve the rate capability of Ni-rich cathode materials,which may be applied to other oxide cathodes with sluggish Li-ion transportation.展开更多
The x-ray compound lens is a novel refractive x-ray optical device. This paper reports the authors' recent research on a polymethyl methacrylate (PMMA) compound x-ray lens. Firstly the designing and LIGA fabricatio...The x-ray compound lens is a novel refractive x-ray optical device. This paper reports the authors' recent research on a polymethyl methacrylate (PMMA) compound x-ray lens. Firstly the designing and LIGA fabrication process for the PMMA compound x-ray lens are briefly described. Then, a method for theoretical analysis, as well as the experimental system for measurement is also introduced. Finally, the focusing spots for 8keV monochromatic x-rays by the PMMA compound x-ray lens are measured and analysed. According to the experimental results, it is concluded that the PMMA compound x-ray lens promises a good focusing performance under the high-energy x-rays.展开更多
In this paper, the axial-flux permanent magnet driver is modeledand analyzed in a simple and novel way under three-dimensional cylindricalcoordinates. The inherent three-dimensional characteristics of the deviceare co...In this paper, the axial-flux permanent magnet driver is modeledand analyzed in a simple and novel way under three-dimensional cylindricalcoordinates. The inherent three-dimensional characteristics of the deviceare comprehensively considered, and the governing equations are solved bysimplifying the boundary conditions. The axial magnetization of the sectorshapedpermanent magnets is accurately described in an algebraic form bythe parameters, which makes the physical meaning more explicit than thepurely mathematical expression in general series forms. The parameters of theBessel function are determined simply and the magnetic field distribution ofpermanent magnets and the air-gap is solved. Furthermore, the field solutionsare completely analytical, which provides convenience and satisfactoryaccuracy for modeling a series of electromagnetic performance parameters,such as the axial electromagnetic force density, axial electromagnetic force,and electromagnetic torque. The correctness and accuracy of the analyticalmodels are fully verified by three-dimensional finite element simulations and a15 kW prototype and the results of calculations, simulations, and experimentsunder three methods are highly consistent. The influence of several designparameters on magnetic field distribution and performance is studied and discussed.The results indicate that the modeling method proposed in this papercan calculate the magnetic field distribution and performance accurately andrapidly, which affords an important reference for the design and optimizationof axial-flux permanent magnet drivers.展开更多
This paper presents a novel geometric parameters analysis to improve the measurement accuracy of stereo deflectometry.Stereo deflectometry can be used to obtain form information for freeform specular surfaces.A measur...This paper presents a novel geometric parameters analysis to improve the measurement accuracy of stereo deflectometry.Stereo deflectometry can be used to obtain form information for freeform specular surfaces.A measurement system based on stereo deflectometry typically consists of a fringe-displaying screen,a main camera,and a reference camera.The arrangement of the components of a stereo deflectometry system is important for achieving high-accuracy measurements.In this paper,four geometric parameters of a stereo deflectometry system are analyzed and evaluated:the distance between the main camera and the measured object surface,the angle between the main camera ray and the surface normal,the distance between the fringe-displaying screen and the object,and the angle between the main camera and the reference camera.The influence of the geometric parameters on the measurement accuracy is evaluated.Experiments are performed using simulated and experimental data.The experimental results confirm the impact of these parameters on the measurement accuracy.A measurement system based on the proposed analysis has been set up to measure a stock concave mirror.Through a comparison of the given surface parameters of the concave mirror,a global measurement accuracy of 154.2 nm was achieved.展开更多
Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects o...Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.展开更多
A novel super-hybrid composite (NSHC) was boron-modified phenolic resin (BPR) with three-dimensional reticulated SiC ceramic (3DRC) and high silica fibers. Ablation performance of the NSHC was studied. The results sho...A novel super-hybrid composite (NSHC) was boron-modified phenolic resin (BPR) with three-dimensional reticulated SiC ceramic (3DRC) and high silica fibers. Ablation performance of the NSHC was studied. The results show that the linear ablation rate of NSHC was lower than that of pure BPR and the high silica/BPR composite. Its linear ablation rate is 1/17 of the high silica/BPR. Mass ablation rate of the NSHC is very close to that of the pure BPR and the high silica/BPR composite. Scanning electron microscope (SEM) analysis indicates that 3DRC has scarcely changed its shape at the ablation temperature. Its special reticulated structure can restrict the materials deformation and prevent high velocity heat flow from eroding the surface of the materials largely and thus increase ablation resistance of the NSHC.展开更多
Ultrasound focusing in three-dimensional(3 D)space is of crucial and enduring significance in a variety of biomedical and industrial applications.Conventional ultrasound focusing based on active phase array or passive...Ultrasound focusing in three-dimensional(3 D)space is of crucial and enduring significance in a variety of biomedical and industrial applications.Conventional ultrasound focusing based on active phase array or passive geometry of bulky size is unable to realize the 3 D arbitrary focusing with subwavelength resolution.Acoustic metamaterial of complex deep-subwavelength microstructure has facilitated the advanced airborne-sound-focusing but is inevitably not applicable for underwater ultrasound,restricted by the law between the multi-modes coupling/thermal viscosity and the feature size of the structure.Here,we aim to circumvent the restriction by increasing the feature size of the metamaterial while keeping the compact overall geometry,and realize the robust subwavelength ultrasound focusing with the sparse metalens of the wavelength-scale meta-atom.We theoretically propose and demonstrate numerically and experimentally the broadband arbitrary ultrasound focusing in 3 D space.The axial and off-axis ultrasound focusing with the subwavelength resolution(FWHM<0.58λ)are achieved by the spatially sparse and compact metalens within one-octave bandwidth.With advantages of 3 D freewheeling focusing,subwavelength resolution,spatial sparsity,geometric simplicity,and broadband,the sparse metalens would offer more initiatives to advanced researches in ultrasound focusing and empower applications such as precise biomedical imaging and therapy,nondestructive evaluation,integrated and multiplexed ultrasound devices.展开更多
In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode (LED), a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, t...In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode (LED), a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.展开更多
We propose and simulate a method for generating a three-dimensional (3D) optical cage in the vicinity of focus by focusing a double-ring shaped radially and azimuthally polarized beam. Our study shows that the combi...We propose and simulate a method for generating a three-dimensional (3D) optical cage in the vicinity of focus by focusing a double-ring shaped radially and azimuthally polarized beam. Our study shows that the combination of an inner ring with an azimuthally polarized field and an outer ring with a radially polarized field and a phase factor can produce an optical cage with a dark region enclosed by higher intensity. The shape of the cage can be tailored by appropriately adjusting the parameters of double-mode beams. Furthermore, multiple 3D optical cages can be realized by applying the shift theorem of the Fourier transform and macro-pixel sampling algorithm to a double-ring shaped radially and azimuthally polarized beam.展开更多
It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunh...It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunhofer diffraction system, it is concluded that the X-ray focusing system can be regarded as a kind of Praunhofer diffraction system. Therefore, a method based on Fourier spectrum analysis is presented to predict the intensity distribution in the focusing plane for the X-ray lenses. A brief analysis on the relationship between the parameters of X-ray lenses and their focusing performance is also given in this paper.展开更多
Based on the heat and mass transfer theory and the characteristics of general-purpose software FLUENT, a three-dimensional numerical simulation platform, composed of lots of user defined functions(UDF), has been devel...Based on the heat and mass transfer theory and the characteristics of general-purpose software FLUENT, a three-dimensional numerical simulation platform, composed of lots of user defined functions(UDF), has been developed to simulate the thermal performance of natural draft wet cooling towers(NDWCTs). After validation, this platform is used to analyse thermal performances of a 220m high super large cooling tower designed for inland nuclear plant under different operational conditions. Variations of outlet temperature of the cooling tower caused by changes of water flow rates, inlet water temperatures are investigated. Effects of optimization through non-uniform water distributions on outlet water temperature are discussed, and the influences on the flow field inside the cooling tower are analyzed in detail. It is found that the outlet water temperature will increase as the water flow rate increases, but the air flow rate will decrease. The outlet water temperature will decrease 0.095K and 0.205K, respectively, if two non-uniform water distribution approaches are applied.展开更多
A method based on the diffraction theory for estimating the three-dimensional (3D) focusing performance of the compound refractive X-ray lenses is presented in this paper. As a special application, the 3D X-ray intens...A method based on the diffraction theory for estimating the three-dimensional (3D) focusing performance of the compound refractive X-ray lenses is presented in this paper. As a special application, the 3D X-ray intensity distribution near the focus is derived for a plano-concave compound refractive X-ray lens. Moreover, the computer codes are developed and some results of 3D focusing performance for a compound refractive X-ray lens with Si material are shown and discussed.展开更多
Three-dimensional printable concrete requires further development owing to the challenges encountered,including its brittle behavior,high cement requirement for the buildability of layers,and anisotropic behavior in d...Three-dimensional printable concrete requires further development owing to the challenges encountered,including its brittle behavior,high cement requirement for the buildability of layers,and anisotropic behavior in different directions.The aim of this study is to overcome these challenges.First,three-dimensional printable concrete mixtures were prepared using silica fume,ground blast furnace slag,and metakaolin,instead of cement,to reduce the amount of cement.Subsequently,the rheological and mechanical behaviors of these concretes were investigated.Second,threedimensional printable concrete mixtures were prepared using 6-mm-long steel and synthetic fibers to eliminate brittleness and determine the effect of those fibers on the anisotropic behavior of the concrete.As a result of this study,it is understood that printable concretes with extremely low permeability and high buildability can be achieved using mineral additives.In addition,results showed that three-dimensional concrete samples containing short steel fibers achieve fracture energies up to 36 times greater than that of plain concrete.Meanwhile,its characteristic length values,as indicators of ductility,are 22 times higher than those of plain concrete.The weakest strength was recorded at the interfaces between layers.The bending and splitting tensile strengths of three-dimensional printed plain concrete samples were 15%and 19%lower than those of casted samples,respectively.However,the addition of fibers improved the mechanical strength of the interfaces significantly.展开更多
文摘The purpose of this study was to evaluate the outcome of patients with unresectable hepatocellular carcinoma(HCC) treated by sequential therapy of transcatheter arterial chemoembolization(TACE),three-dimensional conformal radiotherapy(3-DCRT) and high-intensity focused ultrasound(HIFU).From October,2005 to September,2010,120 patients with unresectable HCC received the sequential treatments of several courses of TACE followed in 2-4 weeks by 3-DCRT and then a single session of HIFU with a curative intent.The median tumor irradiation dose was 40 Gy.Tumor response,toxicity and overall survival rate were analyzed.Clinicopathologic factors affecting the primary technique effectiveness and overall survival rates were investigated by univariate analysis or multivariate analysis.All 120 HCC patients were followed up by the last follow-up time.Among these patients,hepatic toxicities due to treatment were notable in 9 cases.Gastrointestinal bleeding after the overall treatment occurred in 2 cases,leukopenia of grade III was detected in 1 case,radiation-induced liver disease(RILD) was observed in 2 patients,and first-and second-degree skin burn around the HIFU treatment zone were observed in 2 patients and 1 patient,respectively.Among 120 patients,23,83 and 14 cases achieved partial response,stable disease and progressive disease,respectively.The overall survival rates at 1 year,3 years and 5 years were 70%,35% and 15%,respectively,with a median survival time of 26 months.Both Child-Pugh liver function grading and radiation dose were determined to be independent predictors for overall survival revealed by the multivariate analysis.It is concluded that the sequential therapy of TACE,3-DCRT and HIFU is a promising therapeutic regimen for unresectable HCC.
基金the National Key Research and Development Program of China(Grant Nos.2016YFA0200400 and 2016YFA0200800)the National Natural Science Foundation of China(Grant Nos.61888102,12074420,and 11674387)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)Key Research Program of Frontier Sciences,Chinese Acdemy of Sciences(Grant No.QYZDJ-SSWSLH042).
文摘Three-dimensional(3D)vertical architecture transistors represent an important technological pursuit,which have distinct advantages in device integration density,operation speed,and power consumption.However,the fabrication processes of such 3D devices are complex,especially in the interconnection of electrodes.In this paper,we present a novel method which combines suspended electrodes and focused ion beam(FIB)technology to greatly simplify the electrodes interconnection in 3D devices.Based on this method,we fabricate 3D vertical core-double shell structure transistors with ZnO channel and Al_(2)O_(3) gate-oxide both grown by atomic layer deposition.Suspended top electrodes of vertical architecture could be directly connected to planar electrodes by FIB deposited Pt nanowires,which avoid cumbersome steps in the traditional 3D structure fabrication technology.Both single pillar and arrays devices show well behaved transfer characteristics with an Ion/Ioff current ratio greater than 106 and a low threshold voltage around 0 V.The ON-current of the 2×2 pillars vertical channel transistor was 1.2μA at the gate voltage of 3 V and drain voltage of 2 V,which can be also improved by increasing the number of pillars.Our method for fabricating vertical architecture transistors can be promising for device applications with high integration density and low power consumption.
基金Project(51274250)supported by the National Natural Science Foundation of ChinaProject(2012BAK09B02-05)supported by the National Key Technology R&D Program during the 12th Five-year Plan of China
文摘An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.
基金supported by the Ministry of Science and Technology of the People’s Republic of China(2016YFA0202500)the National Natural Science Foundation of China(52072185)+1 种基金the 111 project(B12015)the National Natural Science Foundation of China(21703147 and U1401248)。
文摘Ni-rich layered cathodes(LiNi_xCo_yMn_(2)O_(2))have recently drawn much attention due to their high specific capacities.However,the poor rate capability of LiNi_xCo_yMn_(2)O_(2),which is mainly originated from the twodimensional diffusion of Li ions in the Li slab and Li^(+)/Ni^(2+)cation mixing that hinder the Li^(+)diffusion,has limited their practical application where high power density is needed.Here we integrated Li_(2)MnO_(3)nanodomains into the layered structure of a typical Ni-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)material,which minimized the Li^(+)/Ni^(2+)cationic disordering,and more importantly,established grain boundaries within the NCM811 matrix,thus providing a three-dimensional diffusion channel for Li ions.Accordingly,an average Li-ion diffusion coefficient(D_(Li+))of the Li_(2)MnO_(3)-integrated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811-I)during charge/discharge was calculated to be approximately 6*10^(-10)cm~2 S^(-1),two times of that in the bare NCM811(3*10^(-10)cm~2 S^(-1)).The capacity delivered by the NCM811-I(154.5 mAh g^(-1))was higher than that of NCM811(141.3 mAh g^(-1))at 2 C,and the capacity retention of NCM811-I increased by 13.6%after100 cycles at 0.1 C and 13.4%after 500 cycles at 1 C compared to NCM811.This work provides a valuable routine to improve the rate capability of Ni-rich cathode materials,which may be applied to other oxide cathodes with sluggish Li-ion transportation.
基金Project supported by the National Natural Science Foundation of China (Grant No 10174079), the Natural Science Foundation of Zhejiang Province, China (Grant No Y104203) and BEPC National Laboratory (Grant No sr-03062).
文摘The x-ray compound lens is a novel refractive x-ray optical device. This paper reports the authors' recent research on a polymethyl methacrylate (PMMA) compound x-ray lens. Firstly the designing and LIGA fabrication process for the PMMA compound x-ray lens are briefly described. Then, a method for theoretical analysis, as well as the experimental system for measurement is also introduced. Finally, the focusing spots for 8keV monochromatic x-rays by the PMMA compound x-ray lens are measured and analysed. According to the experimental results, it is concluded that the PMMA compound x-ray lens promises a good focusing performance under the high-energy x-rays.
基金supported by the National Natural Science Foundation of China under Grant[52077027]Liaoning Province Science and Technology Major Project[No.2020JH1/10100020].
文摘In this paper, the axial-flux permanent magnet driver is modeledand analyzed in a simple and novel way under three-dimensional cylindricalcoordinates. The inherent three-dimensional characteristics of the deviceare comprehensively considered, and the governing equations are solved bysimplifying the boundary conditions. The axial magnetization of the sectorshapedpermanent magnets is accurately described in an algebraic form bythe parameters, which makes the physical meaning more explicit than thepurely mathematical expression in general series forms. The parameters of theBessel function are determined simply and the magnetic field distribution ofpermanent magnets and the air-gap is solved. Furthermore, the field solutionsare completely analytical, which provides convenience and satisfactoryaccuracy for modeling a series of electromagnetic performance parameters,such as the axial electromagnetic force density, axial electromagnetic force,and electromagnetic torque. The correctness and accuracy of the analyticalmodels are fully verified by three-dimensional finite element simulations and a15 kW prototype and the results of calculations, simulations, and experimentsunder three methods are highly consistent. The influence of several designparameters on magnetic field distribution and performance is studied and discussed.The results indicate that the modeling method proposed in this papercan calculate the magnetic field distribution and performance accurately andrapidly, which affords an important reference for the design and optimizationof axial-flux permanent magnet drivers.
文摘This paper presents a novel geometric parameters analysis to improve the measurement accuracy of stereo deflectometry.Stereo deflectometry can be used to obtain form information for freeform specular surfaces.A measurement system based on stereo deflectometry typically consists of a fringe-displaying screen,a main camera,and a reference camera.The arrangement of the components of a stereo deflectometry system is important for achieving high-accuracy measurements.In this paper,four geometric parameters of a stereo deflectometry system are analyzed and evaluated:the distance between the main camera and the measured object surface,the angle between the main camera ray and the surface normal,the distance between the fringe-displaying screen and the object,and the angle between the main camera and the reference camera.The influence of the geometric parameters on the measurement accuracy is evaluated.Experiments are performed using simulated and experimental data.The experimental results confirm the impact of these parameters on the measurement accuracy.A measurement system based on the proposed analysis has been set up to measure a stock concave mirror.Through a comparison of the given surface parameters of the concave mirror,a global measurement accuracy of 154.2 nm was achieved.
基金supported by the National Key R&D Program of China(No.2018YFB1502202)the Fundamental Research Funds for the Central Universities(No.FRF-GF-20-09B).
文摘Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.
文摘A novel super-hybrid composite (NSHC) was boron-modified phenolic resin (BPR) with three-dimensional reticulated SiC ceramic (3DRC) and high silica fibers. Ablation performance of the NSHC was studied. The results show that the linear ablation rate of NSHC was lower than that of pure BPR and the high silica/BPR composite. Its linear ablation rate is 1/17 of the high silica/BPR. Mass ablation rate of the NSHC is very close to that of the pure BPR and the high silica/BPR composite. Scanning electron microscope (SEM) analysis indicates that 3DRC has scarcely changed its shape at the ablation temperature. Its special reticulated structure can restrict the materials deformation and prevent high velocity heat flow from eroding the surface of the materials largely and thus increase ablation resistance of the NSHC.
基金supported by the National Natural Science Foundation of China(Grant Nos.11904055,12034005,11827808)the STCSM Science and Technology Innovation Plan of Shanghai Science and Technology Commission(Grant Nos.20ZR1404200,21JC1400300)+2 种基金the Shanghai Chenguang Program(Grant No.20CG02)the Program of Shanghai Academic Research Leader(Grant No.19XD1400500)the Independent Research Project from State Key Laboratory of ASIC and System(Grant No.2021MS007)。
文摘Ultrasound focusing in three-dimensional(3 D)space is of crucial and enduring significance in a variety of biomedical and industrial applications.Conventional ultrasound focusing based on active phase array or passive geometry of bulky size is unable to realize the 3 D arbitrary focusing with subwavelength resolution.Acoustic metamaterial of complex deep-subwavelength microstructure has facilitated the advanced airborne-sound-focusing but is inevitably not applicable for underwater ultrasound,restricted by the law between the multi-modes coupling/thermal viscosity and the feature size of the structure.Here,we aim to circumvent the restriction by increasing the feature size of the metamaterial while keeping the compact overall geometry,and realize the robust subwavelength ultrasound focusing with the sparse metalens of the wavelength-scale meta-atom.We theoretically propose and demonstrate numerically and experimentally the broadband arbitrary ultrasound focusing in 3 D space.The axial and off-axis ultrasound focusing with the subwavelength resolution(FWHM<0.58λ)are achieved by the spatially sparse and compact metalens within one-octave bandwidth.With advantages of 3 D freewheeling focusing,subwavelength resolution,spatial sparsity,geometric simplicity,and broadband,the sparse metalens would offer more initiatives to advanced researches in ultrasound focusing and empower applications such as precise biomedical imaging and therapy,nondestructive evaluation,integrated and multiplexed ultrasound devices.
基金Projects(51575115,51775122)supported by the National Natural Science Foundation of China
文摘In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode (LED), a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.
基金supported in part by the National Natural Science Foundation of China(Nos.91750202,11530046,and 11474156)the National Key R&D Program of China(No.2017YFA0303700)+1 种基金the Collaborative Innovation Center of Advanced Microstructures of Chinathe Collaborative Innovation Center of Solid-State Lighting and Energy-Saving Electronics of China
文摘We propose and simulate a method for generating a three-dimensional (3D) optical cage in the vicinity of focus by focusing a double-ring shaped radially and azimuthally polarized beam. Our study shows that the combination of an inner ring with an azimuthally polarized field and an outer ring with a radially polarized field and a phase factor can produce an optical cage with a dark region enclosed by higher intensity. The shape of the cage can be tailored by appropriately adjusting the parameters of double-mode beams. Furthermore, multiple 3D optical cages can be realized by applying the shift theorem of the Fourier transform and macro-pixel sampling algorithm to a double-ring shaped radially and azimuthally polarized beam.
基金This work was performed with the support from the National Natural Science Foundation of China (No. 10174079) the fund for the qualified researchers in Zhejiang University of Technology, P. R. China.
文摘It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunhofer diffraction system, it is concluded that the X-ray focusing system can be regarded as a kind of Praunhofer diffraction system. Therefore, a method based on Fourier spectrum analysis is presented to predict the intensity distribution in the focusing plane for the X-ray lenses. A brief analysis on the relationship between the parameters of X-ray lenses and their focusing performance is also given in this paper.
基金the National Natural Science Foundation of China (No. 51176170)Foundation for the Author of National Excellent Doctoral Dissertation of PR China (2007B4) are gratefully acknowledged
文摘Based on the heat and mass transfer theory and the characteristics of general-purpose software FLUENT, a three-dimensional numerical simulation platform, composed of lots of user defined functions(UDF), has been developed to simulate the thermal performance of natural draft wet cooling towers(NDWCTs). After validation, this platform is used to analyse thermal performances of a 220m high super large cooling tower designed for inland nuclear plant under different operational conditions. Variations of outlet temperature of the cooling tower caused by changes of water flow rates, inlet water temperatures are investigated. Effects of optimization through non-uniform water distributions on outlet water temperature are discussed, and the influences on the flow field inside the cooling tower are analyzed in detail. It is found that the outlet water temperature will increase as the water flow rate increases, but the air flow rate will decrease. The outlet water temperature will decrease 0.095K and 0.205K, respectively, if two non-uniform water distribution approaches are applied.
基金This work was supported by the National Natural Science Foundation of China (No. 10174079)the fund for the qualified researchers in the Zhejiang University of Technology, P. R. China.
文摘A method based on the diffraction theory for estimating the three-dimensional (3D) focusing performance of the compound refractive X-ray lenses is presented in this paper. As a special application, the 3D X-ray intensity distribution near the focus is derived for a plano-concave compound refractive X-ray lens. Moreover, the computer codes are developed and some results of 3D focusing performance for a compound refractive X-ray lens with Si material are shown and discussed.
基金the author when he was an R&D manager at ISTON.The author would like to thank the technicians at the ISTON R&D laboratory for their assistance.
文摘Three-dimensional printable concrete requires further development owing to the challenges encountered,including its brittle behavior,high cement requirement for the buildability of layers,and anisotropic behavior in different directions.The aim of this study is to overcome these challenges.First,three-dimensional printable concrete mixtures were prepared using silica fume,ground blast furnace slag,and metakaolin,instead of cement,to reduce the amount of cement.Subsequently,the rheological and mechanical behaviors of these concretes were investigated.Second,threedimensional printable concrete mixtures were prepared using 6-mm-long steel and synthetic fibers to eliminate brittleness and determine the effect of those fibers on the anisotropic behavior of the concrete.As a result of this study,it is understood that printable concretes with extremely low permeability and high buildability can be achieved using mineral additives.In addition,results showed that three-dimensional concrete samples containing short steel fibers achieve fracture energies up to 36 times greater than that of plain concrete.Meanwhile,its characteristic length values,as indicators of ductility,are 22 times higher than those of plain concrete.The weakest strength was recorded at the interfaces between layers.The bending and splitting tensile strengths of three-dimensional printed plain concrete samples were 15%and 19%lower than those of casted samples,respectively.However,the addition of fibers improved the mechanical strength of the interfaces significantly.