The selection of an appropriate basic detonation wave flow field is crucial for improving the performance and geometric design of standing detonation vehicles.This paper employs a detailed chemical reaction model and ...The selection of an appropriate basic detonation wave flow field is crucial for improving the performance and geometric design of standing detonation vehicles.This paper employs a detailed chemical reaction model and solves the unsteady axisymmetric Euler equation to study the characteristics of the Axisymmetric Inward Turning Curved Detonation Wave(AIT-CDW)flow field and the parameters affecting the stability of the wave system structure of AIT-CDW flow field.The numerical results demonstrate a radial compression effect in the AIT-CDW flow field.This effect causes the detonation wave to have a shorter initiation length than oblique detonation wave flow field and the detonation wave angle to gradually increase with the flow direction postdetonation.The AIT-CDW flow field is confined space,making it prone to normal detonation waves when the detonation wave reflects from the wall.This phenomenon is detrimental to the stability of the wave system structure in the flow field.It has been observed that increasing the center body radius and decreasing the fuel equivalent ratio can effectively reduce the height of the normal detonation wave or even eliminate it.Additionally,a well-designed generatrix shape of the center body can enhance airflow,reduce choked flow,and promote the stability of the wave structure in the flow field.展开更多
This study investigates the inward flux events following sawtooth crashes in the edge of HL-2A neutral beam heated plasmas.We identified three distinct types of inward fluxes with varying magnitudes and durations,each...This study investigates the inward flux events following sawtooth crashes in the edge of HL-2A neutral beam heated plasmas.We identified three distinct types of inward fluxes with varying magnitudes and durations,each associated with unique plasma parameter fluctuations.Magnetic fluctuations,particularly the disruption of magnetic surface structures caused by sawtooth crashes,may play a significant role in modulating plasma dynamics.Moreover,the crossphase term and coherence between density and velocity fluctuations were found to be key factors in these flux events,with high coherence correlating with peak inward flux.These findings enhance the understanding of fluctuation-induced transport after sawtooth crashes and have implications for plasma confinement in fusion devices.展开更多
Parvalbumin-positive(PV^(+))interneuron dysfunction is believed to be linked to autism spectrum disorder(ASD),a neurodevelopmental disorder characterized by social deficits and stereotypical behaviors.However,the mech...Parvalbumin-positive(PV^(+))interneuron dysfunction is believed to be linked to autism spectrum disorder(ASD),a neurodevelopmental disorder characterized by social deficits and stereotypical behaviors.However,the mechanisms behind PV^(+)interneuron dysfunction remain largely unclear.Here,we found that a deficiency of Biorientation Defective 1(Bod1)in PV^(+)interneurons led to an ASD-like phenotype in Pvalb-Cre;Bod1f/f mice.Mechanistically,we observed that Bod1 deficiency induced hypoactivity of PV^(+)interneurons and hyperactivity of calcium/calmodulin-dependent protein kinaseⅡalpha(CaMKⅡα)neurons in the medial prefrontal cortex,as determined by whole-cell patch-clamp recording.Additionally,Bod1 deficiency decreased the power of highgamma oscillation,assessed by in vivo multi-channel electrophysiological recording.Furthermore,we found that Bod1 deficiency enhanced the inwardly rectifying K^(+)current,leading to an increase in the resting membrane potential of PV^(+)interneurons.Importantly,the gain-of-function of Bod1 improved social deficits and stereotypical behaviors in Pvalb-Cre;Bod1f/f mice.These findings provide mechanistic insights into the PV^(+)interneuron dysfunction and suggest new strategies for developing PV^(+)interneuron-targeted therapies for ASD.展开更多
A design method based on tip to tail streamline tracing and osculating inward cone methods is discussed for designing the integrated Osculating Inward Cone Waverider Inlet（OICWI）. A practical geometrical constrained...A design method based on tip to tail streamline tracing and osculating inward cone methods is discussed for designing the integrated Osculating Inward Cone Waverider Inlet（OICWI）. A practical geometrical constrained experimental model of OICWI is designed based on the validated design method. It has a total contraction ratio of 4.61 and inner contraction ratio is 2.0. Wind-tunnel tests have been conducted for the OICWI model at free stream Mach number（Ma） of 4.0, 3.5 and 3.0 respectively. The experimental results show that the OICWI has high flow capture ratio and compression abilities. It can self-start at Ma= 3.5 and 4.0 and its flow capture ratio is 0.73 at Ma= 4.0, and Angle of Attack（AOA） 0°. The research results show that the OICWI has advantages of inward cone waverider and streamline tracing inlet. Present OICWI is a novel approach for waverider inlet integration studies and it will promote the use of waverider inlet integration configuration in the studies of airbreathing hypersonic vehicles.展开更多
Intensive studies have been carried out on generations of waverider geometry and hypersonic inlet geometry. However, integration efforts of waverider and related air-intake system are restricted majorly around the X43...Intensive studies have been carried out on generations of waverider geometry and hypersonic inlet geometry. However, integration efforts of waverider and related air-intake system are restricted majorly around the X43A-like or conical flow field induced configuration, which adopts mainly the two-dimensional air-breathing technology and limits the judicious visions of developing new aerodynamic profiles for hypersonic designers. A novel design approach for integrating the inward turning inlet with the traditional parameterized waverider is proposed. The proposed method is an alternative means to produce a compatible configuration by linking the off-the-shelf results on both traditional waverider techniques and inward turning inlet techniques. A series of geometry generations and optimization solutions is proposed to enhance the lift-to-drag ratio. A quantitative but efficient aerodynamic performance evaluation approach （the hypersonic flow panel method） with lower computational cost is employed to play the role of objective function for opti- mization purpose. The produced geometry compatibility with a computational fluid dynamics （CFD） solver is also verified for detailed flow field investigation. Optimization results and other numerical validations are obtained for the feasibility demonstration of the proposed method.展开更多
In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the ...In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the basic flow-field, which interacts with the boundary layer to produce a considerable influence on the performance of the inlet. Here, a basic flow-field design method that can control the velocity direction at the throat section is developed, and numerical simulations are conducted to demonstrate the effectiveness of this method. The method presented in this paper can achieve the absorption of the reflected waves at the shoulder of the basic flow-field by adjusting the variation law of the center radius in the basic flow-field, and a smooth transition between the compression surface and the isolator can also be produced. The Mach number and total pressure recovery coefficient of the inlet designed according to this method are 3.00 and 0.657, respectively, at design point(the incoming flow Mach number Ma1= 6.0). The results show that with this method, the inlet can efficiently weaken both the reflection of the shock wave and the interaction between the boundary layer and the reflected shock waves, which improves the aerodynamic performance of the inlet.展开更多
In this paper,the influence of various field shapers and their shapes on the distribution of the magnetic flux densities and applied forces on the work-piece in the electromagnetic inward tube forming are studied nume...In this paper,the influence of various field shapers and their shapes on the distribution of the magnetic flux densities and applied forces on the work-piece in the electromagnetic inward tube forming are studied numerically using the FEA software MAXWELL.First the model was verified with experimental results and thereafter four kinds of field shapers(conical,cylindrical,concave and convex)were considered.Effects of their geometries,such as air gap between field shaper and tube work-piece,height of the step in single and multiple stepped field shaper on magnetic flux densities and magnetic pressures were studied.The results of this research can be applied to design field shaper,tube compression technology,and improve the efficiency of the coil.It is seen that magnetic force decreases if height of step in convex field shaper increases but effective forming region enlarges.Decreasing air gap has also a positive influence on magnetic field increase.Though the object of this research is limited to field shaper for inward tube forming,the results can also be applied to the field shaper for tube bulging.展开更多
Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events a...Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events are significantly slower than the excitatory postsynaptic currents.Parameters of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto rs.Astrocytes are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback loop.Mostly as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological conditions.There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level.These events often occur in synchro ny on neurons located in the same astrocytic domain.Besides synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity.In addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory inputs.Of note,there might be important regionspecific differences in the roles and actions triggering slow inward currents.In greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological ones.Slow inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural networks.Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes.These events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive functions.Events with features overlapping with slow inward currents(excitatory,N-methyl-Daspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke,traumatic brain injury,or epilepsy.One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation.However,to state this,more experimental evidence from greater neuronal networks or the level of the individual is needed.In this review,I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.展开更多
This paper is an attempt to investigate systematically fixed points of weakly inward maps by using some basic results from differential equations in Banach spaces. By investigating the Poincare operators for such diff...This paper is an attempt to investigate systematically fixed points of weakly inward maps by using some basic results from differential equations in Banach spaces. By investigating the Poincare operators for such differential equations, we establish a fixed point index theory for two classes of weakly inward maps.展开更多
In this paper, we discuss the concept of fixed point curve for linear interpolations of weakly inward contractions and establish necessary condition for a nonex- pansive mapping to have approximate fixed point property.
In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the...In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the help of this method, the major design concern of balancing the aerodynamic performance against the requirements for efficient propulsion can be well addressed. A novel geometric parametrically modelling method based on a combination of patched class and shape transition（CST） and COONs surface is proposed to represent the configuration, especially a complex configuration with an irregular inlet lip shape. The modelling method enlarges the design space of components on the premise of guaranteeing the configuration integrity via special constraints imposed on the interface across adjacent surfaces. A basic flow inside a cone shaped by a dual-inflection-point generatrix is optimized to generate the inward-turning inlet with improvements of both compression efficiency and flow uniformity. The performance improvement mechanism of this basic flow is the compression velocity variation induced by the variation of the generatrix slope along the flow path. At the design point, numerical simulation results show that the lift-to-drag ratio of the configuration is as high as 5.2 and the inlet works well with a high level of compression efficiency and flow uniformity. The design result also has a good performance on off-design conditions. The achievement of all the design targets turns out that the integration design method proposed in this paper is efficient and practical.展开更多
In this paper we define a fixed point index theory for locally Lip., completely continuous and weakly inward mappings defined on closed convex sets in general Banach spaces where no other artificial conditions are imp...In this paper we define a fixed point index theory for locally Lip., completely continuous and weakly inward mappings defined on closed convex sets in general Banach spaces where no other artificial conditions are imposed. This makes ns to deal with these kinds of mappings more easily. As obvious applications, some results in [3],[5],[7],[9],[10] are deepened and extended.展开更多
S. Hu and Y. Sun[1] defined the fixed point index for weakly inward mappings, investigated its properties and studied fixed points for such mappings. In this paper, following S. Hu and Y. Sun, we further investigate b...S. Hu and Y. Sun[1] defined the fixed point index for weakly inward mappings, investigated its properties and studied fixed points for such mappings. In this paper, following S. Hu and Y. Sun, we further investigate boundary conditions, under which the fixed point index for i（A, Ω, p） is equal to nonzero, where i（A, Ω, p） is the completely continuous and weakly inward mapping. Correspondingly, we can obtain many new fixed point theorems of the completely continuous and weakly inward mapping, which generalize some famous theorems such as Rothe＇s theorem, Altman＇s theorem, Petryshyn＇s theorem etc. in the case of weakly inward mappings. In addition, our conclusions extend the famous fixed point theorem of cone expansion and compression to the case of weakly inward mappings. Moreover, the main results contain and generalize the corresponding results in the recent work[2].展开更多
The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state discharge.The active control of inward particl...The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state discharge.The active control of inward particle transport is considered as one of the most critical issues of magnetic confinement fusion.Recently,it is realized preliminarily by adding a biased endplate in the Peking University Plasma Test(PPT)device.The results reveal that the inward particle flux increases with the bias voltage of the endplate.It is also found that the profile of radial electric field(Er)shear is flattened by the increased bias voltage.Radial velocity fluctuations affect the inward particle more than density fluctuations,and the frequency of the dominant mode driving inward particle flux increases with the biased voltage applied to the endplate.The experimental results in the PPT device provide a method to actively control the inward particle flux using a biased endplate and enrich the understanding of the relationship between E_(r)×B shear and turbulence transport.展开更多
To determine the effects of HOE 694, a new and potent Na＋- H＋ exchanger blocker, on transient inward current (Iti) and Na＋- Ca2＋ exchange during hypoxia- reoxygenation in guinea pig cardiomyocytes. Methods. Cardio...To determine the effects of HOE 694, a new and potent Na＋- H＋ exchanger blocker, on transient inward current (Iti) and Na＋- Ca2＋ exchange during hypoxia- reoxygenation in guinea pig cardiomyocytes. Methods. Cardiomyocytes were isolated from adult guinea pig ventricle. Experiment was performed in an experimental chamber that allowed the cells to be exposed to a sufficiently low O2 pressure. The cells were subjected to hypoxia and reoxygenation. The ionic currents were studied with patch clamp technique. Results. In the absence of HOE 694, hypoxia- reoxygenation induced Iti in 12 of 15 experiments; but in cardiomyocytes pretreated with HOE 694 (10～ 50μ mol/L), the incidence of Iti observed during reoxygenation was reduced to 5 of 11 experiments and 3 of 10 experiments, P Conclusions. Blockade of the Na＋- H＋ exchange by HOE 694 could reduce Ca2＋ overload upon hypoxia- reoxygenation, and inhibition of Na＋- H＋ exchange may also indirectly decrease Na＋- Ca2＋ exchange activity during hypoxia.展开更多
This paper presents an empirical study of how U.S. antidumping （AD） actions against China affect China ＇s inward and outward foreign direct investment （FDI） based on the international division of labor model. Our...This paper presents an empirical study of how U.S. antidumping （AD） actions against China affect China ＇s inward and outward foreign direct investment （FDI） based on the international division of labor model. Our findings are as follows： （1） The U.S.-China trade deficit has been widened by both downstream firms in China established through vertical FDI and also inward enterprises established through horizontal FDI. The widening deficit in turn exacerbates vitriolic complaints in the U.S. about injury to its industries. This will lead to further U.S. AD actions discouraging FDI in China. （2） U.S. AD cases against China have negatively impacted China＇s metal manufacturing, chemical and, especially, textile industries in terms of exports and inward FDI. From 2004 to 2009, the share of total inward FDI going to China＇s manufacturing sector has dropped drastically by almost 20 percent. This supports predictions made using the international division of labor model. （3） With U.S. AD actions against Chinese products on the rise, Chinese firms chose not to circumvent such barriers through outward FDI in the U.S. but rather through outward FDI in tax havens. Such a pattern of outward FDI is not helpful for China to establish its own successful industrial development model.展开更多
This paper has empirical character and investigates locational determinants of the inward foreign direct investment （FDI） stock among 50 states of the United States. The analysis uses annual data for the period from...This paper has empirical character and investigates locational determinants of the inward foreign direct investment （FDI） stock among 50 states of the United States. The analysis uses annual data for the period from 1997 to 2007. The study identifies several state-specific determinants of FDI and investigates the changes in their importance during the study period. Our results show that among the major determinants, the real per capita income, real per capita expenditure on education, FDI related employment, plus real research and development expenditure are found to have a significant positive impact on inward FDI. There is also evidence that manufacturing density and unionization exert a small positive impact on inward FDI. In addition, per capita state taxes, the share of scientists and engineers in the workforce, real capital expenditure, and unemployment rate exert a negative impact on FDI.展开更多
Stomata play essential roles in sensing environmental stress and transmitting signals to plants.Stomatal opening is triggered by increased H^(+)-ATPase activity,leading to membrane hyperpolarization(Liu and Xue,2021),...Stomata play essential roles in sensing environmental stress and transmitting signals to plants.Stomatal opening is triggered by increased H^(+)-ATPase activity,leading to membrane hyperpolarization(Liu and Xue,2021),thus activating inward potassium(K^(+)_(in))channels(KAT1 and KAT2)and resulting in K^(+)influxes(Qi et al.,2018).Conversely,during the stomatal closure,activation of both slow(S)-type and rapid(R)-type anion channels depolarizes the guard cell membrane(Wang et al.,2016).Hydrogen sulfide(H_(2)S)is a vital signaling molecule in promoting stomatal closure(Papanatsiou et al.,2015;Wang et al.,2016;Liu et al.,2021).展开更多
The effects of La3+ on inward K+ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La3+ on both sides of plasma membrane blocks inward ...The effects of La3+ on inward K+ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La3+ on both sides of plasma membrane blocks inward K+ currents in a concentration- dependent manner, indicating that La3+ binding sites may exist on both sides of plasma membrane in guard cells in vicia. The dose response is fitted by the Michaelis-Menten relation characterized by an inhibitor constant Ki of 2.56±0.25 μmol·L?1 (outside membrane) and (1.18±0.11)×10?15 mol·L?1 (inside membrane). Intracellular La3+ has much stronger inhibitory effect on inward K+ currents than ex- tracellular La3+ does, suggesting there may exist stronger binding sites inside membrane than outside membrane. Since ion channel activities of guard cells directly affect plant stomatal movement and water status, our results imply that rare earth elements might have potential practical values in regulating plant water status and strengthening plant drought endurance.展开更多
This paper constructs a two-stage sequential game model to shed light on the spillover effect of inward FDI on the efficiency of domestic firms in host countries.Our model shows that,given an optimal joint-venture pol...This paper constructs a two-stage sequential game model to shed light on the spillover effect of inward FDI on the efficiency of domestic firms in host countries.Our model shows that,given an optimal joint-venture policy made by foreign firms,the impact of the spillover effect of inward FDI is contingent upon the productivity gap between the domestic firms and foreign ones.In particular,we demonstrate that the spillover effect of inward FDI varies negatively with the productivity gap between domestic lowproductivity firms and foreign firms but works in the opposite way for high-productivity firms.This suggests that once the productivity gap widens,the entry of foreign firms will increase the efficiency of high-productivity firms but reduce the efficiency of lowproductivity firms.In support of our theoretical model,we provide robust empirical results by using the dataset of annual survey of Chinese industrial enterprises.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U20A2069,62376234 and 123B2037)the Advanced Aero-Power Innovation Workstation,China(No.HKCX2024-01-017)。
文摘The selection of an appropriate basic detonation wave flow field is crucial for improving the performance and geometric design of standing detonation vehicles.This paper employs a detailed chemical reaction model and solves the unsteady axisymmetric Euler equation to study the characteristics of the Axisymmetric Inward Turning Curved Detonation Wave(AIT-CDW)flow field and the parameters affecting the stability of the wave system structure of AIT-CDW flow field.The numerical results demonstrate a radial compression effect in the AIT-CDW flow field.This effect causes the detonation wave to have a shorter initiation length than oblique detonation wave flow field and the detonation wave angle to gradually increase with the flow direction postdetonation.The AIT-CDW flow field is confined space,making it prone to normal detonation waves when the detonation wave reflects from the wall.This phenomenon is detrimental to the stability of the wave system structure in the flow field.It has been observed that increasing the center body radius and decreasing the fuel equivalent ratio can effectively reduce the height of the normal detonation wave or even eliminate it.Additionally,a well-designed generatrix shape of the center body can enhance airflow,reduce choked flow,and promote the stability of the wave structure in the flow field.
基金support of these experiments.This work was supported by the National Natural Science Foundation of China(12405268,12175227,11875255,12375226,and 11975231)the National Magnetic Confinement Fusion Science Program of China(2022YFE03060003,2022YFE03100004)+1 种基金the Fundamental Research Funds for the Central Universities(WK2140000016)the China Postdoctoral Science Foundation(2022M723066).
文摘This study investigates the inward flux events following sawtooth crashes in the edge of HL-2A neutral beam heated plasmas.We identified three distinct types of inward fluxes with varying magnitudes and durations,each associated with unique plasma parameter fluctuations.Magnetic fluctuations,particularly the disruption of magnetic surface structures caused by sawtooth crashes,may play a significant role in modulating plasma dynamics.Moreover,the crossphase term and coherence between density and velocity fluctuations were found to be key factors in these flux events,with high coherence correlating with peak inward flux.These findings enhance the understanding of fluctuation-induced transport after sawtooth crashes and have implications for plasma confinement in fusion devices.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0108600 to Y.M.L.)the National Natural Science Foundations of China(Grant Nos.82473918 and 82104162 to X.X.L.).
文摘Parvalbumin-positive(PV^(+))interneuron dysfunction is believed to be linked to autism spectrum disorder(ASD),a neurodevelopmental disorder characterized by social deficits and stereotypical behaviors.However,the mechanisms behind PV^(+)interneuron dysfunction remain largely unclear.Here,we found that a deficiency of Biorientation Defective 1(Bod1)in PV^(+)interneurons led to an ASD-like phenotype in Pvalb-Cre;Bod1f/f mice.Mechanistically,we observed that Bod1 deficiency induced hypoactivity of PV^(+)interneurons and hyperactivity of calcium/calmodulin-dependent protein kinaseⅡalpha(CaMKⅡα)neurons in the medial prefrontal cortex,as determined by whole-cell patch-clamp recording.Additionally,Bod1 deficiency decreased the power of highgamma oscillation,assessed by in vivo multi-channel electrophysiological recording.Furthermore,we found that Bod1 deficiency enhanced the inwardly rectifying K^(+)current,leading to an increase in the resting membrane potential of PV^(+)interneurons.Importantly,the gain-of-function of Bod1 improved social deficits and stereotypical behaviors in Pvalb-Cre;Bod1f/f mice.These findings provide mechanistic insights into the PV^(+)interneuron dysfunction and suggest new strategies for developing PV^(+)interneuron-targeted therapies for ASD.
基金supported by the National Natural Science Foundation of China (Nos. 51376192 and 91216303)
文摘A design method based on tip to tail streamline tracing and osculating inward cone methods is discussed for designing the integrated Osculating Inward Cone Waverider Inlet（OICWI）. A practical geometrical constrained experimental model of OICWI is designed based on the validated design method. It has a total contraction ratio of 4.61 and inner contraction ratio is 2.0. Wind-tunnel tests have been conducted for the OICWI model at free stream Mach number（Ma） of 4.0, 3.5 and 3.0 respectively. The experimental results show that the OICWI has high flow capture ratio and compression abilities. It can self-start at Ma= 3.5 and 4.0 and its flow capture ratio is 0.73 at Ma= 4.0, and Angle of Attack（AOA） 0°. The research results show that the OICWI has advantages of inward cone waverider and streamline tracing inlet. Present OICWI is a novel approach for waverider inlet integration studies and it will promote the use of waverider inlet integration configuration in the studies of airbreathing hypersonic vehicles.
基金supported by the National Natural Science Foundation of China (Grant No.61004089)
文摘Intensive studies have been carried out on generations of waverider geometry and hypersonic inlet geometry. However, integration efforts of waverider and related air-intake system are restricted majorly around the X43A-like or conical flow field induced configuration, which adopts mainly the two-dimensional air-breathing technology and limits the judicious visions of developing new aerodynamic profiles for hypersonic designers. A novel design approach for integrating the inward turning inlet with the traditional parameterized waverider is proposed. The proposed method is an alternative means to produce a compatible configuration by linking the off-the-shelf results on both traditional waverider techniques and inward turning inlet techniques. A series of geometry generations and optimization solutions is proposed to enhance the lift-to-drag ratio. A quantitative but efficient aerodynamic performance evaluation approach （the hypersonic flow panel method） with lower computational cost is employed to play the role of objective function for opti- mization purpose. The produced geometry compatibility with a computational fluid dynamics （CFD） solver is also verified for detailed flow field investigation. Optimization results and other numerical validations are obtained for the feasibility demonstration of the proposed method.
基金supported by the National Natural Science Foundation of China (Nos. 11702229, 11602207 and 91641103)
文摘In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the basic flow-field, which interacts with the boundary layer to produce a considerable influence on the performance of the inlet. Here, a basic flow-field design method that can control the velocity direction at the throat section is developed, and numerical simulations are conducted to demonstrate the effectiveness of this method. The method presented in this paper can achieve the absorption of the reflected waves at the shoulder of the basic flow-field by adjusting the variation law of the center radius in the basic flow-field, and a smooth transition between the compression surface and the isolator can also be produced. The Mach number and total pressure recovery coefficient of the inlet designed according to this method are 3.00 and 0.657, respectively, at design point(the incoming flow Mach number Ma1= 6.0). The results show that with this method, the inlet can efficiently weaken both the reflection of the shock wave and the interaction between the boundary layer and the reflected shock waves, which improves the aerodynamic performance of the inlet.
文摘In this paper,the influence of various field shapers and their shapes on the distribution of the magnetic flux densities and applied forces on the work-piece in the electromagnetic inward tube forming are studied numerically using the FEA software MAXWELL.First the model was verified with experimental results and thereafter four kinds of field shapers(conical,cylindrical,concave and convex)were considered.Effects of their geometries,such as air gap between field shaper and tube work-piece,height of the step in single and multiple stepped field shaper on magnetic flux densities and magnetic pressures were studied.The results of this research can be applied to design field shaper,tube compression technology,and improve the efficiency of the coil.It is seen that magnetic force decreases if height of step in convex field shaper increases but effective forming region enlarges.Decreasing air gap has also a positive influence on magnetic field increase.Though the object of this research is limited to field shaper for inward tube forming,the results can also be applied to the field shaper for tube bulging.
基金funded by the National Research Developm ent and Innovation Office (NKFIH-K1468 73) (to BP)。
文摘Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events are significantly slower than the excitatory postsynaptic currents.Parameters of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto rs.Astrocytes are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback loop.Mostly as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological conditions.There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level.These events often occur in synchro ny on neurons located in the same astrocytic domain.Besides synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity.In addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory inputs.Of note,there might be important regionspecific differences in the roles and actions triggering slow inward currents.In greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological ones.Slow inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural networks.Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes.These events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive functions.Events with features overlapping with slow inward currents(excitatory,N-methyl-Daspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke,traumatic brain injury,or epilepsy.One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation.However,to state this,more experimental evidence from greater neuronal networks or the level of the individual is needed.In this review,I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.
文摘This paper is an attempt to investigate systematically fixed points of weakly inward maps by using some basic results from differential equations in Banach spaces. By investigating the Poincare operators for such differential equations, we establish a fixed point index theory for two classes of weakly inward maps.
文摘In this paper, we discuss the concept of fixed point curve for linear interpolations of weakly inward contractions and establish necessary condition for a nonex- pansive mapping to have approximate fixed point property.
基金supported by the ‘‘111" Project of China (No. B17037)
文摘In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the help of this method, the major design concern of balancing the aerodynamic performance against the requirements for efficient propulsion can be well addressed. A novel geometric parametrically modelling method based on a combination of patched class and shape transition（CST） and COONs surface is proposed to represent the configuration, especially a complex configuration with an irregular inlet lip shape. The modelling method enlarges the design space of components on the premise of guaranteeing the configuration integrity via special constraints imposed on the interface across adjacent surfaces. A basic flow inside a cone shaped by a dual-inflection-point generatrix is optimized to generate the inward-turning inlet with improvements of both compression efficiency and flow uniformity. The performance improvement mechanism of this basic flow is the compression velocity variation induced by the variation of the generatrix slope along the flow path. At the design point, numerical simulation results show that the lift-to-drag ratio of the configuration is as high as 5.2 and the inlet works well with a high level of compression efficiency and flow uniformity. The design result also has a good performance on off-design conditions. The achievement of all the design targets turns out that the integration design method proposed in this paper is efficient and practical.
文摘In this paper we define a fixed point index theory for locally Lip., completely continuous and weakly inward mappings defined on closed convex sets in general Banach spaces where no other artificial conditions are imposed. This makes ns to deal with these kinds of mappings more easily. As obvious applications, some results in [3],[5],[7],[9],[10] are deepened and extended.
基金Supported in part by the Foundations of Education Ministry, Anhui Province, China (No: KJ2008A028)Education Ministry, Hubei Province, China (No: D20102502)
文摘S. Hu and Y. Sun[1] defined the fixed point index for weakly inward mappings, investigated its properties and studied fixed points for such mappings. In this paper, following S. Hu and Y. Sun, we further investigate boundary conditions, under which the fixed point index for i（A, Ω, p） is equal to nonzero, where i（A, Ω, p） is the completely continuous and weakly inward mapping. Correspondingly, we can obtain many new fixed point theorems of the completely continuous and weakly inward mapping, which generalize some famous theorems such as Rothe＇s theorem, Altman＇s theorem, Petryshyn＇s theorem etc. in the case of weakly inward mappings. In addition, our conclusions extend the famous fixed point theorem of cone expansion and compression to the case of weakly inward mappings. Moreover, the main results contain and generalize the corresponding results in the recent work[2].
基金supported by the National MCF Energy R&D Program of China(No.2018YFE0303100)National Natural Science Foundation of China(No.11975038)。
文摘The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state discharge.The active control of inward particle transport is considered as one of the most critical issues of magnetic confinement fusion.Recently,it is realized preliminarily by adding a biased endplate in the Peking University Plasma Test(PPT)device.The results reveal that the inward particle flux increases with the bias voltage of the endplate.It is also found that the profile of radial electric field(Er)shear is flattened by the increased bias voltage.Radial velocity fluctuations affect the inward particle more than density fluctuations,and the frequency of the dominant mode driving inward particle flux increases with the biased voltage applied to the endplate.The experimental results in the PPT device provide a method to actively control the inward particle flux using a biased endplate and enrich the understanding of the relationship between E_(r)×B shear and turbulence transport.
基金This work was supported by Leading Specialty Funding of Shanghai, Grant No.94- III- 001.
文摘To determine the effects of HOE 694, a new and potent Na＋- H＋ exchanger blocker, on transient inward current (Iti) and Na＋- Ca2＋ exchange during hypoxia- reoxygenation in guinea pig cardiomyocytes. Methods. Cardiomyocytes were isolated from adult guinea pig ventricle. Experiment was performed in an experimental chamber that allowed the cells to be exposed to a sufficiently low O2 pressure. The cells were subjected to hypoxia and reoxygenation. The ionic currents were studied with patch clamp technique. Results. In the absence of HOE 694, hypoxia- reoxygenation induced Iti in 12 of 15 experiments; but in cardiomyocytes pretreated with HOE 694 (10～ 50μ mol/L), the incidence of Iti observed during reoxygenation was reduced to 5 of 11 experiments and 3 of 10 experiments, P Conclusions. Blockade of the Na＋- H＋ exchange by HOE 694 could reduce Ca2＋ overload upon hypoxia- reoxygenation, and inhibition of Na＋- H＋ exchange may also indirectly decrease Na＋- Ca2＋ exchange activity during hypoxia.
基金This paper is sponsored by the Chinese National Social Science Foundation Project （grant llBJY142）, Chinese MOE Project of Key Research Institute of Humanities and Social Sciences at Universities （grant 08JJD790138）, Shanghai Pujiang Program Project （grant 2011C）, Shu Guang Project of Shanghai Educational Development Foundation （grant llSGl0） and 985＇Third Period Project of Fudan University （grant 2011SHKXZD002）.
文摘This paper presents an empirical study of how U.S. antidumping （AD） actions against China affect China ＇s inward and outward foreign direct investment （FDI） based on the international division of labor model. Our findings are as follows： （1） The U.S.-China trade deficit has been widened by both downstream firms in China established through vertical FDI and also inward enterprises established through horizontal FDI. The widening deficit in turn exacerbates vitriolic complaints in the U.S. about injury to its industries. This will lead to further U.S. AD actions discouraging FDI in China. （2） U.S. AD cases against China have negatively impacted China＇s metal manufacturing, chemical and, especially, textile industries in terms of exports and inward FDI. From 2004 to 2009, the share of total inward FDI going to China＇s manufacturing sector has dropped drastically by almost 20 percent. This supports predictions made using the international division of labor model. （3） With U.S. AD actions against Chinese products on the rise, Chinese firms chose not to circumvent such barriers through outward FDI in the U.S. but rather through outward FDI in tax havens. Such a pattern of outward FDI is not helpful for China to establish its own successful industrial development model.
文摘This paper has empirical character and investigates locational determinants of the inward foreign direct investment （FDI） stock among 50 states of the United States. The analysis uses annual data for the period from 1997 to 2007. The study identifies several state-specific determinants of FDI and investigates the changes in their importance during the study period. Our results show that among the major determinants, the real per capita income, real per capita expenditure on education, FDI related employment, plus real research and development expenditure are found to have a significant positive impact on inward FDI. There is also evidence that manufacturing density and unionization exert a small positive impact on inward FDI. In addition, per capita state taxes, the share of scientists and engineers in the workforce, real capital expenditure, and unemployment rate exert a negative impact on FDI.
基金funded by the National Natural Science Foundation of China(32070214,31670267)the Postdoctoral Fellowship Program of CPSF(GZC20230908)+1 种基金the China Postdoctoral Science Foundation(CN:2023M741289)the Postdoctor Project of Hubei Province under Grant No.2004HBBHCXA042。
文摘Stomata play essential roles in sensing environmental stress and transmitting signals to plants.Stomatal opening is triggered by increased H^(+)-ATPase activity,leading to membrane hyperpolarization(Liu and Xue,2021),thus activating inward potassium(K^(+)_(in))channels(KAT1 and KAT2)and resulting in K^(+)influxes(Qi et al.,2018).Conversely,during the stomatal closure,activation of both slow(S)-type and rapid(R)-type anion channels depolarizes the guard cell membrane(Wang et al.,2016).Hydrogen sulfide(H_(2)S)is a vital signaling molecule in promoting stomatal closure(Papanatsiou et al.,2015;Wang et al.,2016;Liu et al.,2021).
基金the National Natural Science Foundat ion of China(Grant No.20171031) the Shanxi Provincial Natural Science Foundation.
文摘The effects of La3+ on inward K+ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La3+ on both sides of plasma membrane blocks inward K+ currents in a concentration- dependent manner, indicating that La3+ binding sites may exist on both sides of plasma membrane in guard cells in vicia. The dose response is fitted by the Michaelis-Menten relation characterized by an inhibitor constant Ki of 2.56±0.25 μmol·L?1 (outside membrane) and (1.18±0.11)×10?15 mol·L?1 (inside membrane). Intracellular La3+ has much stronger inhibitory effect on inward K+ currents than ex- tracellular La3+ does, suggesting there may exist stronger binding sites inside membrane than outside membrane. Since ion channel activities of guard cells directly affect plant stomatal movement and water status, our results imply that rare earth elements might have potential practical values in regulating plant water status and strengthening plant drought endurance.
文摘This paper constructs a two-stage sequential game model to shed light on the spillover effect of inward FDI on the efficiency of domestic firms in host countries.Our model shows that,given an optimal joint-venture policy made by foreign firms,the impact of the spillover effect of inward FDI is contingent upon the productivity gap between the domestic firms and foreign ones.In particular,we demonstrate that the spillover effect of inward FDI varies negatively with the productivity gap between domestic lowproductivity firms and foreign firms but works in the opposite way for high-productivity firms.This suggests that once the productivity gap widens,the entry of foreign firms will increase the efficiency of high-productivity firms but reduce the efficiency of lowproductivity firms.In support of our theoretical model,we provide robust empirical results by using the dataset of annual survey of Chinese industrial enterprises.
