The low-Reynolds-number full developed turbulent flow in channels is simulated using large eddy simulation(LES)method with the preconditioned algorithm and the dynamic subgrid-scale model,with a given disturbance in...The low-Reynolds-number full developed turbulent flow in channels is simulated using large eddy simulation(LES)method with the preconditioned algorithm and the dynamic subgrid-scale model,with a given disturbance in inlet boundary,after a short development section.The inlet Reynolds number based on momentum thickness is 670.The computed results show good agreement with direct numerical simulation(DNS),which include root mean square fluctuated velocity distribution and average velocity distribution.It is also found that the staggered phenomenon of the coherent structures is caused by sub-harmonic.The results clearly show the formation and evolution of horseshoe vortex in the turbulent boundary layer,including horseshoe vortex structure with a pair of streamwise vortexes and one-side leg of horseshoe vortex.Based on the results,the development of the horseshoe-shaped coherent structures is analyzed in turbulent boundary layer.展开更多
To reduce the cost, size and complexity, a consumer digital camera usually uses a single sensor overlaid with a color filter array(CFA) to sample one of the red-green-blue primary color values, and uses demosaicking a...To reduce the cost, size and complexity, a consumer digital camera usually uses a single sensor overlaid with a color filter array(CFA) to sample one of the red-green-blue primary color values, and uses demosaicking algorithm to estimate the missing color values at each pixel. A novel image correlation and support vector machine(SVM) based edge-adaptive algorithm was proposed, which can reduce edge artifacts and false color artifacts, effectively. Firstly, image pixels were separated into edge region and smooth region with an edge detection algorithm. Then, a hybrid approach switching between a simple demosaicking algorithm on the smooth region and SVM based demosaicking algorithm on the edge region was performed. Image spatial and spectral correlations were employed to create middle planes for the interpolation. Experimental result shows that the proposed approach produced visually pleasing full-color result images and obtained higher CPSNR and smaller S-CIELAB*ab?E than other conventional demosaicking algorithms.展开更多
To investigate the effects of long-term low dose hormone replacement therapy (HRT) on postmenopaosal women in homone level, cognition score, hippocampus volume, and magnetic resonance spectroscopy (MRS) parameters...To investigate the effects of long-term low dose hormone replacement therapy (HRT) on postmenopaosal women in homone level, cognition score, hippocampus volume, and magnetic resonance spectroscopy (MRS) parameters. Methods A total of 182 postmenopausal women aged 50-87 years were chosen at Peking Union Medical College Hospital and assigned to HRT group and control group. The volunteers of HRT group had taken low dose hormone [ estradiol (E2 ) 0. 5-1.0 mg and progesterone 0.5-2.0 mg, once a day ] for 4-33 years. The concentrations of E2, progesterone, and testosterone were measured using enzyme-linked immunosorbent assay (ELISA). The gene types of apolipoprotein E (ApoE) were measured by polymerase chain reaction, and the subjects with susceptible genes ( ApoE ε3/ε4) of Alzheimer's disease (AD) were screened. Their hippocampus volumes and MRS parameters were obtained through magnetic resonance imaging (MRI), and results in two groups were analyzed by statistical method. Results Compared with control group, the concentrations of E2 at each age stage in HRT group were significantly higher (P 〈0. 05) except the 80-89 years old subgroup; yet, there were no statistical differences in the concentrations of progesterone and testosterone between the two groups. There was no obvious difference in ApoE subtypes distribution between the two groups The results of hippocampus MRI for the subjects with susceptible genes ApoE ε3/ε4 (HRT group 14 cases, control group 11 cases) showed that the ratio of bilateral hippocampus volume to whole brain volume in HRT group (0. 406 ± 0.028) was signiticantlyhigher than control gronp (0.369±0.031, P〈0.05). Theresults of ^1H MRS for the subjects with susceptible genes ApoE ε3/ε4 ( HRT group 12 cases, control group 11 cases) showed that the N-acetylaspartate/total creatine at the area of hippocampus in HRT group ( 1.54±0. 08 ) were significantly higher than control group ( 1.45±0. 13, P 〈 0. 05). Conclusions For postmenopausal women, long-term low dose HRT can maintain the physiological concentration of E2 in plasma. Furthermore, the hippocampus MRI performed on those with ApoE ε3/ε3 genes shows that long-term low dose HRT can prevent hippocampus atrophy, which is beneficial to maintain the brain function and prevent AD.展开更多
The traditional products' quality is often recognized based on organoleptic characteristics without considering the microbiological features, which bring a special note to these products' composition and aroma. It i...The traditional products' quality is often recognized based on organoleptic characteristics without considering the microbiological features, which bring a special note to these products' composition and aroma. It is especially the case of cheeses, whose taste varies from one geographical region to another depending on specific flora and technological processes used in traditional systems. The paper tries to bring new elements on the methodology used in order to elucidate some aspects related to traditional products' quality, products obtained by private producers in the Bra^ov district (Rucar-Bran pass). Covasna district and Bistrita Nasaud district were analyzed organoleptically, physico-chemically and microbiologically samples of fresh cow cheese, soft cow cheese, smoked curd cheese, gaiter cheese and cottage cheese taken within the strategic and self-control program from individuals in the rural areas of Fundata, Poiana Sibiului, Sirnea, Pfirliu, Cristian, Cincaor, Sohodol, Ranov, Brarov, Bod, Roadea, Harnan, Prejmer, Soars, Rupea, Lunca Calnicului, Balanii, Mari, Bran, Buzaiel, Bacut, H~.lchiu, Fagraa, Moeciu de Sus, Purcaareni, Bran-Simon, Venelia de Jos, Vama Buzatului, lntorsura Buzaului, Vatrghia and Sita Buzaului.展开更多
Objective: To investigate the activation (phosphorylation) and subcellular localization of extracellular signal-regulated kinase (ERK1/2), as well as the possible mechanism, following cerebral ischemia and ischem...Objective: To investigate the activation (phosphorylation) and subcellular localization of extracellular signal-regulated kinase (ERK1/2), as well as the possible mechanism, following cerebral ischemia and ischemia/reperfusion in rat hippocampus. Methods: Transient brain ischemia was induced by the four-vessel occlusion method in Sprague-Dawley rats. Western blot analysis. Results: During cerebral ischemia without reperfusion ERK1/2 activation immediately increased with a peak at 5 min and then decreased in the cytosol fraction, which was paralleled by the increase of ERK1/2 activation in the nucleus fraction. During reperfusion, ERK1/2 was activated with peaks occurring at 10 min in the cytosol and at 30 min in the nucleus, respectively. Under those conditions, the protein expressions had no significant change. In order to clarify the possible mechanism of ERK1/2 activation, the rats were intraperitoneally administrated with N-methyl-D-aspartate (NMDA) receptor antagonist dextromethorphan (DM), L-type voltage-gated Ca^2+ channel (L-VGCC) antagonist nifedipine (ND) 20 rain before ischemia, finding that DM and ND markedly prevented ERK1/2 activation of nucleus fraction induced by reperfusion, not by ischemia. Conclusion: These results suggested that the nuclear translocation mainly occurred during ischemia, while ischemia-reperfusion induced ERK1/2 activation both in the cytosol and the nucleus. Two type calcium channels contributed, at least partially, to the activation of ERK1/2.展开更多
Abstract: The present study is an attempt to apply the concept of plant and pollen indicators to habitat conditions in different soil strata at archaeological site (Lake Qarun). It revealed a great palaeoenvironmen...Abstract: The present study is an attempt to apply the concept of plant and pollen indicators to habitat conditions in different soil strata at archaeological site (Lake Qarun). It revealed a great palaeoenvironmental information's about habitat changing of Lake Qarun from a humid and wet conditions during the Hellenic Period to reed swampy early Roman, to Nile Flooding middle Roman, to mesophytic habitats Late Roman, also changing to halophytic and salt marshes with presence of Chenopodiaceae at recent time. Using indicator plants and their remains i.e. pollen grains and spores, palynological studies of different soil strata revealed that, presence of 13 pollen and spore types e.g. Lycopodium, Typhaceae type, Juncaceae, Poaceae, Cyperaceae, Caryophyllaceae, Chenopodiaceae, Nymphaeaceae, Fabaceae, Asteraceae, Tamaricaceae, Onagraceae and Lamiaceae. The data obtained were valuable in reconstruct past vegetation and habitats conditions of Lake Qarun during Helleno Roman period.展开更多
For the formation of nature reserves can directly affect the livelihood of indigenous people living in the area, negotiation between the authority and the community is crucial to the management of the natural resource...For the formation of nature reserves can directly affect the livelihood of indigenous people living in the area, negotiation between the authority and the community is crucial to the management of the natural resources. Crocker Range Park is the largest state park in Sabah state, Malaysia. Since there is a village community living within the boundary of the nature reserve, the state government and the villagers have had a conflict over the land rights. Until the government and the village delegation reached an agreement on the park's management plan in 2015, three actors intervened in the conflict: PACOS Trust, Japan International Cooperation Agency (JICA), and Japan Overseas Cooperation Volunteers (JOCV). In this study, these interventions by different actors were analyzed with the Tripartite Conflict Management (TCM} model. The results indicate that JOCV was the sole actor that was able to communicate with both the state government and the villagers. To support the result, a preliminary research was conducted, and the villagers' perception was investigated through a questionnaire survey. This paper concludes that JOCV was perceived as an actor that can be trusted more than JICA and the state government. This conclusion supports the result of the analysis of TCM model.展开更多
Fast reciprocating probe systems ( FRPS ) are widely used in some tokamaks, such as JT- 60 U, TEXT and DIlI-D. The parameters with high temporal-spatial resolution are measured for boundary plasmas using these syste...Fast reciprocating probe systems ( FRPS ) are widely used in some tokamaks, such as JT- 60 U, TEXT and DIlI-D. The parameters with high temporal-spatial resolution are measured for boundary plasmas using these systems. The FRPS on HL-2A is developed, which is composed of transmission bar, digital grating displacement system, electromagnetic valves, stepping motor and so on. The high-pressure gas from the electromagnetic valves controlled by trigger signals provides the power to drive the transmission bar forward or backward. Reciprocating distance is 8 cm with the maximum speed of 1.5 m·s^-1.展开更多
The edge plasma characteristics are studied by a movable array of Mach/Reynolds stress/Langmuir 10-probes and fast reciprocating 4-probes in the boundary region. These probes can measure edge plasma temperature, densi...The edge plasma characteristics are studied by a movable array of Mach/Reynolds stress/Langmuir 10-probes and fast reciprocating 4-probes in the boundary region. These probes can measure edge plasma temperature, density, poloidal electric field, radial electric field, Reynolds stress, poloidal rotation velocities and their profiles obtained by changing the radial positions of the probe array in different discharges. Measurement resuits are used to analyze plasma confinement, turbulent fluctuations and their correlation. The fixed flush 3-probe arrays are mounted on the 4-divertor neutralization plates at the same toroidal cross-section in divertor chamber. These probes are used to measure the profiles of the electron temperature, density and float potential in divertor chamber.展开更多
Because the last closed flux-surface (LCFS) finally determines the shape of plasma cross-section, and the shaping of plasma is a key issue directly related with lots of the hot subjects of an advanced tokamak(AT) ...Because the last closed flux-surface (LCFS) finally determines the shape of plasma cross-section, and the shaping of plasma is a key issue directly related with lots of the hot subjects of an advanced tokamak(AT) and of a reactor, e. g., the control on the current density, equilibrium, scrapeoff layer(SOL), aspects of edge particle and energy, high plasma kinetic energy, and of course, the MHD instability suppression, the further studies on the LCFS related subjects, e. g., its determination, flux loss, etc., are still tokamak research. It equilibrium, poloidal needed for present is also important to get precise LCFS-related equilibrium or configuration properties for the controls on an AT and for the understandings on the underlying basic physical issues in a discharge.展开更多
Horseshoe vortex topological structure has been studied extensively in the past,traditional"saddle of separation"and new"attachment saddle point"topologies found in literature both have theoretical...Horseshoe vortex topological structure has been studied extensively in the past,traditional"saddle of separation"and new"attachment saddle point"topologies found in literature both have theoretical basis and experimental and computational evidences for support.The laminar incompressible juncture flows at low Reynolds numbers especially are observed to have new topology.Studies concerning the existence of the new topology though found in literature,the topological evolution and its dependency on various critical flow parameters require further investigation.A Particle Image Velocimetry based analysis is carried out to observe the effect of aspect ratio,?*/D and shape of the obstacle on laminar horseshoe vortex topology for small obstacles.Rise in aspect ratio evolves the topology from the traditional to new for all the cases observed.The circular cross section obstacles are found more apt to having the new topology compared to square cross sections.It is noted that the sweeping effect of the fluid above the vortex system in which horseshoe vortex is immersed plays a critical role in this evolution.Topological evolution is observed not only in the most upstream singular point region of horseshoe vortex system but also in the corner region.The corner vortex topology evolves from the traditional type to new one before the topological evolution of the most upstream singular point,resulting in a new topological pattern of the laminar juncture flows"separation-attachment combination".The study may help extend the understanding of the three-dimensional boundary layer separation phenomenon.展开更多
This paper reports the direct numerical simulation (DNS) for hypersonic turbulent boundary layer over a flat-plate at Ma∞ =8 with the ratio of wall-to-freestream temperature equal to 1.9, which indicates an extremely...This paper reports the direct numerical simulation (DNS) for hypersonic turbulent boundary layer over a flat-plate at Ma∞ =8 with the ratio of wall-to-freestream temperature equal to 1.9, which indicates an extremely cold wall condition. It is primarily used to assess the wall temperature effects on the mean velocity profile, Walz equation, turbulent intensity, strong Reynolds analogy (SRA), and compressibility. The present high Mach number with cold wall condition induces strong compressibility effects. As a result, the Morkovin's hypothesis is not fully valid and so the classical SRA is also not fully consistent. However, some modified SRA is still valid at the far-wall region. It is also verified that the semi-local wall coordinate y* is better than conventional y+ in analysis of statistics features in turbulent boundary layer (TBL) in hypersonic flow.展开更多
The object of this paper is to study the non-tangential increasing properties of positiveharmonic function u in Lipschitz domain by means of Martin representation theory. A necessaryand sufficient condition of the con...The object of this paper is to study the non-tangential increasing properties of positiveharmonic function u in Lipschitz domain by means of Martin representation theory. A necessaryand sufficient condition of the control of growth of u near any fixed boundary point is obtained.It is shown that the non-tangential increasing degree of u near a boundary point is exactlythe local degree of its representation measure with respect to the harmonic measure. Someexamples are given.展开更多
The aerodynamic performance of a gas turbine nozzle vane cascade was investigated over a range of Mach and Reynolds numbers.The work is part of a vast research project aimed at the analysis of fluid dynamics and heat ...The aerodynamic performance of a gas turbine nozzle vane cascade was investigated over a range of Mach and Reynolds numbers.The work is part of a vast research project aimed at the analysis of fluid dynamics and heat transfer phenomena in cooled blades.In this paper computed results on the"solid vane"(without cooling devices)are presented and discussed in comparison with experimental data.Detailed measurements were provided by the University of Bergamo where the experimental campaign was carried out by means of a subsonic wind tunnel.The impact of boundary layer transition is investigated by using a novel laminar kinetic energy transport model and the widely used Langtry-Menterγ-Reθ,t model.The comparison between calculations and measurements is presented in terms of blade loading distributions,total pressure loss coefficient contours downstream of the cascade,and velocity/turbulence-intensity profiles within the boundary layer at selected blade surface locations at mid-span.It will be shown how transitional calculations compare favorably with experiments.展开更多
We define a new Markov chain on the symbolic space representing the Sierpinski gasket (SG),and show that the corresponding Martin boundary is homeomorphic to the SG while the minimal Martin boundary is the three verti...We define a new Markov chain on the symbolic space representing the Sierpinski gasket (SG),and show that the corresponding Martin boundary is homeomorphic to the SG while the minimal Martin boundary is the three vertices of the SG.In addition,the harmonic structure induced by the Markov chain coincides with the canonical one on the SG.This suggests another approach to consider the existence of Laplacians on those self-similar sets for which the problem is still not settled.展开更多
This paper investigates a multi-period mean-variance portfolio selection with regime switching and uncertain exit time. The returns of assets all depend on the states of the stochastic market which are assumed to foll...This paper investigates a multi-period mean-variance portfolio selection with regime switching and uncertain exit time. The returns of assets all depend on the states of the stochastic market which are assumed to follow a discrete-time Markov chain. The authors derive the optimal strategy and the efficient frontier of the model in closed-form. Some results in the existing literature are obtained as special cases of our results.展开更多
基金Supported by the National Natural Science Foundation of China(10772082)~~
文摘The low-Reynolds-number full developed turbulent flow in channels is simulated using large eddy simulation(LES)method with the preconditioned algorithm and the dynamic subgrid-scale model,with a given disturbance in inlet boundary,after a short development section.The inlet Reynolds number based on momentum thickness is 670.The computed results show good agreement with direct numerical simulation(DNS),which include root mean square fluctuated velocity distribution and average velocity distribution.It is also found that the staggered phenomenon of the coherent structures is caused by sub-harmonic.The results clearly show the formation and evolution of horseshoe vortex in the turbulent boundary layer,including horseshoe vortex structure with a pair of streamwise vortexes and one-side leg of horseshoe vortex.Based on the results,the development of the horseshoe-shaped coherent structures is analyzed in turbulent boundary layer.
基金Projects(51174258,11105002)supported by the National Natural Science Foundation of ChinaProject(KJ2013B087)supported by Anhui Provincial Natural Science Research Projects in Central Universities,China+1 种基金Projects(2011B31,2013A4017)support by the Guidance Science and Technology Plan Projects of Huainan,ChinaProject(2012QNZ06)supported by the Youth Foundation of Anhui University of Science&technology of China
文摘To reduce the cost, size and complexity, a consumer digital camera usually uses a single sensor overlaid with a color filter array(CFA) to sample one of the red-green-blue primary color values, and uses demosaicking algorithm to estimate the missing color values at each pixel. A novel image correlation and support vector machine(SVM) based edge-adaptive algorithm was proposed, which can reduce edge artifacts and false color artifacts, effectively. Firstly, image pixels were separated into edge region and smooth region with an edge detection algorithm. Then, a hybrid approach switching between a simple demosaicking algorithm on the smooth region and SVM based demosaicking algorithm on the edge region was performed. Image spatial and spectral correlations were employed to create middle planes for the interpolation. Experimental result shows that the proposed approach produced visually pleasing full-color result images and obtained higher CPSNR and smaller S-CIELAB*ab?E than other conventional demosaicking algorithms.
文摘To investigate the effects of long-term low dose hormone replacement therapy (HRT) on postmenopaosal women in homone level, cognition score, hippocampus volume, and magnetic resonance spectroscopy (MRS) parameters. Methods A total of 182 postmenopausal women aged 50-87 years were chosen at Peking Union Medical College Hospital and assigned to HRT group and control group. The volunteers of HRT group had taken low dose hormone [ estradiol (E2 ) 0. 5-1.0 mg and progesterone 0.5-2.0 mg, once a day ] for 4-33 years. The concentrations of E2, progesterone, and testosterone were measured using enzyme-linked immunosorbent assay (ELISA). The gene types of apolipoprotein E (ApoE) were measured by polymerase chain reaction, and the subjects with susceptible genes ( ApoE ε3/ε4) of Alzheimer's disease (AD) were screened. Their hippocampus volumes and MRS parameters were obtained through magnetic resonance imaging (MRI), and results in two groups were analyzed by statistical method. Results Compared with control group, the concentrations of E2 at each age stage in HRT group were significantly higher (P 〈0. 05) except the 80-89 years old subgroup; yet, there were no statistical differences in the concentrations of progesterone and testosterone between the two groups. There was no obvious difference in ApoE subtypes distribution between the two groups The results of hippocampus MRI for the subjects with susceptible genes ApoE ε3/ε4 (HRT group 14 cases, control group 11 cases) showed that the ratio of bilateral hippocampus volume to whole brain volume in HRT group (0. 406 ± 0.028) was signiticantlyhigher than control gronp (0.369±0.031, P〈0.05). Theresults of ^1H MRS for the subjects with susceptible genes ApoE ε3/ε4 ( HRT group 12 cases, control group 11 cases) showed that the N-acetylaspartate/total creatine at the area of hippocampus in HRT group ( 1.54±0. 08 ) were significantly higher than control group ( 1.45±0. 13, P 〈 0. 05). Conclusions For postmenopausal women, long-term low dose HRT can maintain the physiological concentration of E2 in plasma. Furthermore, the hippocampus MRI performed on those with ApoE ε3/ε3 genes shows that long-term low dose HRT can prevent hippocampus atrophy, which is beneficial to maintain the brain function and prevent AD.
文摘The traditional products' quality is often recognized based on organoleptic characteristics without considering the microbiological features, which bring a special note to these products' composition and aroma. It is especially the case of cheeses, whose taste varies from one geographical region to another depending on specific flora and technological processes used in traditional systems. The paper tries to bring new elements on the methodology used in order to elucidate some aspects related to traditional products' quality, products obtained by private producers in the Bra^ov district (Rucar-Bran pass). Covasna district and Bistrita Nasaud district were analyzed organoleptically, physico-chemically and microbiologically samples of fresh cow cheese, soft cow cheese, smoked curd cheese, gaiter cheese and cottage cheese taken within the strategic and self-control program from individuals in the rural areas of Fundata, Poiana Sibiului, Sirnea, Pfirliu, Cristian, Cincaor, Sohodol, Ranov, Brarov, Bod, Roadea, Harnan, Prejmer, Soars, Rupea, Lunca Calnicului, Balanii, Mari, Bran, Buzaiel, Bacut, H~.lchiu, Fagraa, Moeciu de Sus, Purcaareni, Bran-Simon, Venelia de Jos, Vama Buzatului, lntorsura Buzaului, Vatrghia and Sita Buzaului.
基金Supported by grants from the Education Departmental Natural Science Research Funds of Hebei and Jiangsu Provinces of China (200510604KJD310207)the Key Project of the National Natural Science Foundation of China (No. 30330190).
文摘Objective: To investigate the activation (phosphorylation) and subcellular localization of extracellular signal-regulated kinase (ERK1/2), as well as the possible mechanism, following cerebral ischemia and ischemia/reperfusion in rat hippocampus. Methods: Transient brain ischemia was induced by the four-vessel occlusion method in Sprague-Dawley rats. Western blot analysis. Results: During cerebral ischemia without reperfusion ERK1/2 activation immediately increased with a peak at 5 min and then decreased in the cytosol fraction, which was paralleled by the increase of ERK1/2 activation in the nucleus fraction. During reperfusion, ERK1/2 was activated with peaks occurring at 10 min in the cytosol and at 30 min in the nucleus, respectively. Under those conditions, the protein expressions had no significant change. In order to clarify the possible mechanism of ERK1/2 activation, the rats were intraperitoneally administrated with N-methyl-D-aspartate (NMDA) receptor antagonist dextromethorphan (DM), L-type voltage-gated Ca^2+ channel (L-VGCC) antagonist nifedipine (ND) 20 rain before ischemia, finding that DM and ND markedly prevented ERK1/2 activation of nucleus fraction induced by reperfusion, not by ischemia. Conclusion: These results suggested that the nuclear translocation mainly occurred during ischemia, while ischemia-reperfusion induced ERK1/2 activation both in the cytosol and the nucleus. Two type calcium channels contributed, at least partially, to the activation of ERK1/2.
文摘Abstract: The present study is an attempt to apply the concept of plant and pollen indicators to habitat conditions in different soil strata at archaeological site (Lake Qarun). It revealed a great palaeoenvironmental information's about habitat changing of Lake Qarun from a humid and wet conditions during the Hellenic Period to reed swampy early Roman, to Nile Flooding middle Roman, to mesophytic habitats Late Roman, also changing to halophytic and salt marshes with presence of Chenopodiaceae at recent time. Using indicator plants and their remains i.e. pollen grains and spores, palynological studies of different soil strata revealed that, presence of 13 pollen and spore types e.g. Lycopodium, Typhaceae type, Juncaceae, Poaceae, Cyperaceae, Caryophyllaceae, Chenopodiaceae, Nymphaeaceae, Fabaceae, Asteraceae, Tamaricaceae, Onagraceae and Lamiaceae. The data obtained were valuable in reconstruct past vegetation and habitats conditions of Lake Qarun during Helleno Roman period.
文摘For the formation of nature reserves can directly affect the livelihood of indigenous people living in the area, negotiation between the authority and the community is crucial to the management of the natural resources. Crocker Range Park is the largest state park in Sabah state, Malaysia. Since there is a village community living within the boundary of the nature reserve, the state government and the villagers have had a conflict over the land rights. Until the government and the village delegation reached an agreement on the park's management plan in 2015, three actors intervened in the conflict: PACOS Trust, Japan International Cooperation Agency (JICA), and Japan Overseas Cooperation Volunteers (JOCV). In this study, these interventions by different actors were analyzed with the Tripartite Conflict Management (TCM} model. The results indicate that JOCV was the sole actor that was able to communicate with both the state government and the villagers. To support the result, a preliminary research was conducted, and the villagers' perception was investigated through a questionnaire survey. This paper concludes that JOCV was perceived as an actor that can be trusted more than JICA and the state government. This conclusion supports the result of the analysis of TCM model.
文摘Fast reciprocating probe systems ( FRPS ) are widely used in some tokamaks, such as JT- 60 U, TEXT and DIlI-D. The parameters with high temporal-spatial resolution are measured for boundary plasmas using these systems. The FRPS on HL-2A is developed, which is composed of transmission bar, digital grating displacement system, electromagnetic valves, stepping motor and so on. The high-pressure gas from the electromagnetic valves controlled by trigger signals provides the power to drive the transmission bar forward or backward. Reciprocating distance is 8 cm with the maximum speed of 1.5 m·s^-1.
文摘The edge plasma characteristics are studied by a movable array of Mach/Reynolds stress/Langmuir 10-probes and fast reciprocating 4-probes in the boundary region. These probes can measure edge plasma temperature, density, poloidal electric field, radial electric field, Reynolds stress, poloidal rotation velocities and their profiles obtained by changing the radial positions of the probe array in different discharges. Measurement resuits are used to analyze plasma confinement, turbulent fluctuations and their correlation. The fixed flush 3-probe arrays are mounted on the 4-divertor neutralization plates at the same toroidal cross-section in divertor chamber. These probes are used to measure the profiles of the electron temperature, density and float potential in divertor chamber.
基金Supported by the National Natural Science Foundation of China(10175022), and Sichuan Provincial Youth Foundation for Science and Technology (04zp026-032)
文摘Because the last closed flux-surface (LCFS) finally determines the shape of plasma cross-section, and the shaping of plasma is a key issue directly related with lots of the hot subjects of an advanced tokamak(AT) and of a reactor, e. g., the control on the current density, equilibrium, scrapeoff layer(SOL), aspects of edge particle and energy, high plasma kinetic energy, and of course, the MHD instability suppression, the further studies on the LCFS related subjects, e. g., its determination, flux loss, etc., are still tokamak research. It equilibrium, poloidal needed for present is also important to get precise LCFS-related equilibrium or configuration properties for the controls on an AT and for the understandings on the underlying basic physical issues in a discharge.
基金supported by the National Natural Science Foundation of China(Grant No.11372027)
文摘Horseshoe vortex topological structure has been studied extensively in the past,traditional"saddle of separation"and new"attachment saddle point"topologies found in literature both have theoretical basis and experimental and computational evidences for support.The laminar incompressible juncture flows at low Reynolds numbers especially are observed to have new topology.Studies concerning the existence of the new topology though found in literature,the topological evolution and its dependency on various critical flow parameters require further investigation.A Particle Image Velocimetry based analysis is carried out to observe the effect of aspect ratio,?*/D and shape of the obstacle on laminar horseshoe vortex topology for small obstacles.Rise in aspect ratio evolves the topology from the traditional to new for all the cases observed.The circular cross section obstacles are found more apt to having the new topology compared to square cross sections.It is noted that the sweeping effect of the fluid above the vortex system in which horseshoe vortex is immersed plays a critical role in this evolution.Topological evolution is observed not only in the most upstream singular point region of horseshoe vortex system but also in the corner region.The corner vortex topology evolves from the traditional type to new one before the topological evolution of the most upstream singular point,resulting in a new topological pattern of the laminar juncture flows"separation-attachment combination".The study may help extend the understanding of the three-dimensional boundary layer separation phenomenon.
基金supported by the National Nature Science Foundation of China(Grant No. 11072248)the National Basic Research Program(Grant No. 2009CB724100)+1 种基金the National High-tech R&D Program(No.2012AA01A304)the CAS Information Project(INFO-115-B01)
文摘This paper reports the direct numerical simulation (DNS) for hypersonic turbulent boundary layer over a flat-plate at Ma∞ =8 with the ratio of wall-to-freestream temperature equal to 1.9, which indicates an extremely cold wall condition. It is primarily used to assess the wall temperature effects on the mean velocity profile, Walz equation, turbulent intensity, strong Reynolds analogy (SRA), and compressibility. The present high Mach number with cold wall condition induces strong compressibility effects. As a result, the Morkovin's hypothesis is not fully valid and so the classical SRA is also not fully consistent. However, some modified SRA is still valid at the far-wall region. It is also verified that the semi-local wall coordinate y* is better than conventional y+ in analysis of statistics features in turbulent boundary layer (TBL) in hypersonic flow.
基金Project supported by the National Natural Science Foundation of China
文摘The object of this paper is to study the non-tangential increasing properties of positiveharmonic function u in Lipschitz domain by means of Martin representation theory. A necessaryand sufficient condition of the control of growth of u near any fixed boundary point is obtained.It is shown that the non-tangential increasing degree of u near a boundary point is exactlythe local degree of its representation measure with respect to the harmonic measure. Someexamples are given.
基金the project INSIDE(Aerothermal Investigation of cooled Stage turb Ine:Design optimization and Experimental analysis)PRIN 2011 n.2010K3B4RLfunded by the Italian Ministry of Instruction,University and Research(MIUR)
文摘The aerodynamic performance of a gas turbine nozzle vane cascade was investigated over a range of Mach and Reynolds numbers.The work is part of a vast research project aimed at the analysis of fluid dynamics and heat transfer phenomena in cooled blades.In this paper computed results on the"solid vane"(without cooling devices)are presented and discussed in comparison with experimental data.Detailed measurements were provided by the University of Bergamo where the experimental campaign was carried out by means of a subsonic wind tunnel.The impact of boundary layer transition is investigated by using a novel laminar kinetic energy transport model and the widely used Langtry-Menterγ-Reθ,t model.The comparison between calculations and measurements is presented in terms of blade loading distributions,total pressure loss coefficient contours downstream of the cascade,and velocity/turbulence-intensity profiles within the boundary layer at selected blade surface locations at mid-span.It will be shown how transitional calculations compare favorably with experiments.
文摘We define a new Markov chain on the symbolic space representing the Sierpinski gasket (SG),and show that the corresponding Martin boundary is homeomorphic to the SG while the minimal Martin boundary is the three vertices of the SG.In addition,the harmonic structure induced by the Markov chain coincides with the canonical one on the SG.This suggests another approach to consider the existence of Laplacians on those self-similar sets for which the problem is still not settled.
基金This research is supported by the National Science Foundation for Distinguished Young Scholars under Grant No. 70825002, the National Natural Science Foundation of China under Grant No. 70518001, and the National Basic Research Program of China 973 Program, under Grant No. 2007CB814902.
文摘This paper investigates a multi-period mean-variance portfolio selection with regime switching and uncertain exit time. The returns of assets all depend on the states of the stochastic market which are assumed to follow a discrete-time Markov chain. The authors derive the optimal strategy and the efficient frontier of the model in closed-form. Some results in the existing literature are obtained as special cases of our results.