In order to inquire into the therapeutic effects of Xin Mai Tong Capsule (心脉通胶囊) on coronary heart disease with myocardial ischemia, 40 patients were randomly divided into two groups (Xin Mai Tong group and the c...In order to inquire into the therapeutic effects of Xin Mai Tong Capsule (心脉通胶囊) on coronary heart disease with myocardial ischemia, 40 patients were randomly divided into two groups (Xin Mai Tong group and the control group). The plasma endothelin (ET) levels in the two groups of patients were markedly higher than that of the healthy people (P<0.001), and the calcitonin gene related peptide (CGRP) was similar to that of the healthy people (P>0.05). After treatment, ET and symptomatic scores in the two groups decreased markedly (P<0.01), and their S-T segments were elevated obviously (P<0.01). But the decrease of ET and symptomatic scores and elevation of S-T segment in Xin Mai Tong group were superior to those of the control group (P<0.05~0.01). The CGRP level in the control group did not vary obviously post-treatment, but it increased markedly (P<0.01) with the addition of Xin Mai Tong Capsule in Xin Mai Tong group.展开更多
In considering next-nearest neighbor (NNN) coupling, we numerically investigate the magnetoelastic instability in ring-shaped mesoscopic antiferromagnetic Heisenberg spin 1/2 systems with spin-phonon interaction. Th...In considering next-nearest neighbor (NNN) coupling, we numerically investigate the magnetoelastic instability in ring-shaped mesoscopic antiferromagnetic Heisenberg spin 1/2 systems with spin-phonon interaction. The results indicate that, for antiferromagnetic NNN coupling J2, there may be a critical value J2^c, at which the ground state is dimerized for arbitrary lattice spring constant and beyond and below which the magnetoelastic instability behavior is different from each other. The values of J2^c are irrelevant to the system size. For ferromagnetic NNN coupling, only continuous transition is present from dimerized phase to uniform phase as lattice spring constant is increased.展开更多
The modulational instability of ion-acoustic wave in a collisionless, unmagnetized plasma consisting of warm ions, hot isothermal electrons, and relativistic electron beam is studied. A modified nonlinear Schr?dinger ...The modulational instability of ion-acoustic wave in a collisionless, unmagnetized plasma consisting of warm ions, hot isothermal electrons, and relativistic electron beam is studied. A modified nonlinear Schr?dinger equation including one additional term that comes from the effect of relativistic electron beam is derived. It is found that the inclusion of a relativistic electron beam would modify the modulational instability of the wave packet and could not admit any stationary soliton waves.展开更多
Relativistic mean-field theory and phase-shift analysis are combined together to investigate the elasticCoulomb scattering between electrons and unstable nuclei.Electron scattering at several different energies is stu...Relativistic mean-field theory and phase-shift analysis are combined together to investigate the elasticCoulomb scattering between electrons and unstable nuclei.Electron scattering at several different energies is studiedand compared,in order to see the energy dependence of electron-nucleus scattering.It is shown that electron scattering at200 MeV or 300 MeV can be used to reveal electron-nucleus scattering information around the first diffraction minimum-Shiftsin opposite directions are obtained for the first diffraction minima of the electron scattering off the ground andfirst excited states of ^(17)F with ^(16)O as reference,and similar effects are obtained for ^(18)Ne.Besides,some neutron-richN = 8 isotones are also studied.Results show that electron scattering will be very useful and important in studyingboth proton- and neutron-rich nuclei in the future.展开更多
Incubation of camazepam [3-(N,N-dimethyl) carbamoyloxy-7-chloro-1- methyl-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one] with rat liver microsomes and cofactors produced a 3-(N-methyl-N-hydroxymethyl) carbamoyloxy d...Incubation of camazepam [3-(N,N-dimethyl) carbamoyloxy-7-chloro-1- methyl-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one] with rat liver microsomes and cofactors produced a 3-(N-methyl-N-hydroxymethyl) carbamoyloxy derivative as the most abundant metabolite.This metabolite was thermally unstable and was isolated from a metabolite mixture by normal-phase High-Performance Liquid Chromatography.Its struc- ture was established by chemical ionization and ^(252)Cf plasma desorption time-of-flight mass spectral analyses.展开更多
The adsorption state and catalytic properties of pepsin and acidic protease from microorganisms Asp. awamori and Asp. oryzae were studied in solid phase system (in presence of sorsilen, DEAE- and CM-cellulose). Acco...The adsorption state and catalytic properties of pepsin and acidic protease from microorganisms Asp. awamori and Asp. oryzae were studied in solid phase system (in presence of sorsilen, DEAE- and CM-cellulose). According to the results, adsorption capacity and catalytic activity of enzymes depend on the physical nature of surface groups of the solid phase. Changing the stability of enzymes in the system with solid phase is observed even the adsorption bond is less stable (in the case of DEAE- and CM-cellulose in acidic media). Injection to the medium ethanol, surfactants, sodium chloride and changing the temperature of the incubation medium could prevent the negative effects of the solid phases. When sorsilen is used as solid phase, pepsin and acidic protease from Asp. awamori suffer from high surface inactivation. Various surfactants influence adsorption state of enzymes differently. Non-ionic surfactants (Triton X-100) prevent adsorption and restore catalytic properties of enzymes.展开更多
This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2+2 with an invariant manifold. The slow-fast system in R2+: has a 2-dimensional slow vector field and a 2-dimensional f...This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2+2 with an invariant manifold. The slow-fast system in R2+: has a 2-dimensional slow vector field and a 2-dimensional fast vector field. The fast vector field restricts a feasible region of the slow vector field strictly. In the case of the slow-fast system in R2+1 , that is, the fast vector field is l-dimension, it is classified according to its sign, because it gives only negative(-), positive(+) or zero sign. Then it is attractive, repulsive or stationary. On the other hand, in R2~2 , the fast vector field has combinatorial cases. It causes a complex state to analyze the system. First, we introduce a local model near the pseudo singular point on which we classify the fast vector field attractive(-,-), attractive-repulsive(-,+) or repulsive(+,+), simply as possible. We prove the existence of a 4-dimensional duck solution in the local model. Secondarily, we assume that the slow-fast system has an invariant manifold near the pseudo singular point. When the invariant manifold has a homoclinic point near the pseudo singular point, we show that the slow-fast sytem has a 4-dimensional duck solution having a relatively stable region.展开更多
This study focused on the way that Adolescents with Transfusion- dependent thalassemia explained negative or positive events in their life (Attributional Styles). It is defined by three dimensions describing the cog...This study focused on the way that Adolescents with Transfusion- dependent thalassemia explained negative or positive events in their life (Attributional Styles). It is defined by three dimensions describing the cognitive appraisal of the events: internal-external, stable-unstable, and global-specific. With cross-sectional research design, the observations consist of 102 adolescents (48 males, 54 females) who diagnosed with Transfusion-dependent thalassemia (more than 50 times for blood transfusions) completed the measure of Attributional Styles and Anxiety Questionnaires. The correlations in the predicted directions among variables examine with Pearson product-moment correlation coefficients, t-test, and One-way ANOVA to ascertain a significant between the group differences on attributional factors and levels of anxiety symptoms. The results show that Adolescent samples with higher levels of anxiety revealed statistically significant relationship among three negative attributional dimensions (overall composite F = 4.5, p 〈 0.05; negative composite F = 4.99, p 〈 0.01; negative-internality F = 4.99 p 〈 0.01; negative-stability F = 3.42, p 〈 0.05 and negative-globality F = 3.77, p 〈 0.05). In addition, significant age- group differences were found for the total negative-globality (t = 2.05, p 〈 0.05) and negative- globality (t = -2.22, p 〈 0.05). These data are consistent with the reformulated learned helplessness model of depression. In finding, the individuals who attribute negative life events to internal, stable, and global causes will be more vulnerable to anxiety than those who make external, unstable, and specific attributions. Most interestingly, those adolescents more than 17 years evidence more negative-globality attfibutional style than group less than 16 years, and female adolescents may influence this pattern. These results suggest that targeting Adolescents with Transfusion-dependent thalassemia may be important for improving aspect of coping on psychological adjustment to their chronic illness.展开更多
In order to find out the influence of the instability of angular velocity of the rotating carrier itself on the stability of silicon micromachined gyroscope, the digital models for relative error of the high and low d...In order to find out the influence of the instability of angular velocity of the rotating carrier itself on the stability of silicon micromachined gyroscope, the digital models for relative error of the high and low damping gyroscope's output signal are given respectively, based on the motion equations of the silicon micromachined gyroscope. Theory proves that the output signal error of the silicon micromachined sensor is mainly caused by the instability of damping factor and the angular velocity of the rotating carrier itself. The experiment result indicates that the error of proportionality coefficient of output voltage which is caused by the instability of the angular velocity of the rotating carrier itself reaches to 4.1 %. Theoretical demonstration and experimental verification show that the instability of angular velocity of the rotating carrier itself has an important effect on the stability of low damping silicon micromachined gyroscope.展开更多
An experimental investigation is described for the characteristics of convective boiling flow instabilities in horizontally helically coiled tubes using a steam-water two-phase closed circulation test loop at pressure...An experimental investigation is described for the characteristics of convective boiling flow instabilities in horizontally helically coiled tubes using a steam-water two-phase closed circulation test loop at pressure from 0.5 MPa to 3.5 MPa. Three kinds of oscillation are reported: density waves; pressure drop excursions; thermal fluctuations. We describe their dependence on main system parameters such as system pressure, mass flowrate, inlet subcooling, compressible volume and heat flux. Utilizing the experimental data together with conservation constraints, a dimensionless correlation is proposed for the occurrence of density waves.展开更多
In order to clarify the natures of a rotating stall cell, the experimental investigation was carried out in a high specific-speed diagonal flow fan. The pressure field on the casing wall and the velocity fields at the...In order to clarify the natures of a rotating stall cell, the experimental investigation was carried out in a high specific-speed diagonal flow fan. The pressure field on the casing wall and the velocity fields at the rotor inlet and outlet were measured under rotating stall condition with a fast response pressure transducer and a single slant hot-wire probe, respectively. The data were processed using the “Double Phase-Locked Averaging (DPLA)”technique, which enabled to obtain the unsteady flow field with a rotating stall cell in the relative co-ordinate system fixed to the rotor. As a result, the structure and behavior of the rotating stall cell in a high specific-speed diagonal flow fan were shown.展开更多
The meta-instable state(MIS)is the final stage before fault instability during stick-slip movement.Thus,identification of MIS is of great significance for assessing earthquake hazard in fault zones.A rock sample with ...The meta-instable state(MIS)is the final stage before fault instability during stick-slip movement.Thus,identification of MIS is of great significance for assessing earthquake hazard in fault zones.A rock sample with a precut planar fault was loaded on a horizontally biaxial servo-controlled press machine to create stick-slip conditions.Digital images of the sample surface were taken by a high-speed camera at a rate of 1000 frames per second during the stick-slip motion and processed using a 2D digital image correlation method to obtain the displacement field.We define a synergism coefficient that describes the relative dispersion of the accumulative fault slip.The results reveal that:(1)a local pre-slip area spreads very slowly along the fault before the MIS develops.It extends at a higher but still slow speed during meta-instable state I(MIS-I).During the final^1.5%of MIS,in meta-instable state II(MIS-II),the local pre-slip area first extends at a speed of^0.9 m/s,and then expands out of the observed image area at a very high speed.These results indicate that the local pre-slip area transforms from a state of quasi-static extension in MIS-I to quasi-dynamic extension in MIS-II.(2)The synergism coefficient of the fault slip decreases to half of its original value in MIS-I and to a quarter of its original value in MIS-II.This continuous decrease of synergism coefficient indicates that the strengthening of fault slip synergism is a characteristic of MIS.(3)Furthermore,the unstable sliding stage includes three sliding processes:initial-,fast-,and adjusted-sliding.There are two pauses between the three sliding processes.展开更多
This article proposes a relay camera videometrics based method to convert an unstable measuring platform to a static reference to solve the problems of large error or invalidation caused by measuring platform instabil...This article proposes a relay camera videometrics based method to convert an unstable measuring platform to a static reference to solve the problems of large error or invalidation caused by measuring platform instability in photogrammetric and videometric measurements.The method installs a relay camera on the unstable platform and captures images of a reference marker fixed on a static reference or vice versa to resolve the 3D movement of the unstable platform relative to the static reference,based on which it corrects the error of the measured results and thus eliminating the influence of the platform movement.It finds new and important applications for videometrics by making high-precision dynamic measurement possible on unstable platforms.Verification experiments and numerical simulations have proven its validity and practicability.展开更多
Boiling flow instability of nitrogen in a vertical tube is experimentally investigated in the present study. The experiments reveal that pressure has a significant effect on the characteristics of the heat flux-mass f...Boiling flow instability of nitrogen in a vertical tube is experimentally investigated in the present study. The experiments reveal that pressure has a significant effect on the characteristics of the heat flux-mass flux type boiling flow instability.First.the pressure has strong effects on both the developing time and the fluctuation amplitude.Especially increasing pressure leads to decrease the fluctuating amplitude of mass flux.Then,the mass flux evolving curves under different pressures feature out a shape like a leaf.The characteristics of the heat flux-mass flux type boiling flow instability under lower pressure are very complicated,however,with increasing pressure,this type of instability is gradually suppressed.展开更多
The mechanism of the Weibel instability is investigated for dense magnetized plasmas. As we know, due to the electron velocity distribution, the Coulomb collision effect of electron-ion and the relativistic properties...The mechanism of the Weibel instability is investigated for dense magnetized plasmas. As we know, due to the electron velocity distribution, the Coulomb collision effect of electron-ion and the relativistic properties play an important role in such study. In this study an analytical expression for the growth rate and the condition of restricting the Weibel instability are derived for low-frequency limit. These calculations are done for the oscillation frequency dependence on the electron cyclotron frequency. It is shown that, the relativistic properties of the particle lead to increasing the growth rate of the instability. On the other hand the collision effects and background magnetic field try to decrease the growth rate by decreasing the temperature anisotropy and restricting the particles movement.展开更多
文摘In order to inquire into the therapeutic effects of Xin Mai Tong Capsule (心脉通胶囊) on coronary heart disease with myocardial ischemia, 40 patients were randomly divided into two groups (Xin Mai Tong group and the control group). The plasma endothelin (ET) levels in the two groups of patients were markedly higher than that of the healthy people (P<0.001), and the calcitonin gene related peptide (CGRP) was similar to that of the healthy people (P>0.05). After treatment, ET and symptomatic scores in the two groups decreased markedly (P<0.01), and their S-T segments were elevated obviously (P<0.01). But the decrease of ET and symptomatic scores and elevation of S-T segment in Xin Mai Tong group were superior to those of the control group (P<0.05~0.01). The CGRP level in the control group did not vary obviously post-treatment, but it increased markedly (P<0.01) with the addition of Xin Mai Tong Capsule in Xin Mai Tong group.
文摘In considering next-nearest neighbor (NNN) coupling, we numerically investigate the magnetoelastic instability in ring-shaped mesoscopic antiferromagnetic Heisenberg spin 1/2 systems with spin-phonon interaction. The results indicate that, for antiferromagnetic NNN coupling J2, there may be a critical value J2^c, at which the ground state is dimerized for arbitrary lattice spring constant and beyond and below which the magnetoelastic instability behavior is different from each other. The values of J2^c are irrelevant to the system size. For ferromagnetic NNN coupling, only continuous transition is present from dimerized phase to uniform phase as lattice spring constant is increased.
文摘The modulational instability of ion-acoustic wave in a collisionless, unmagnetized plasma consisting of warm ions, hot isothermal electrons, and relativistic electron beam is studied. A modified nonlinear Schr?dinger equation including one additional term that comes from the effect of relativistic electron beam is derived. It is found that the inclusion of a relativistic electron beam would modify the modulational instability of the wave packet and could not admit any stationary soliton waves.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10535010,10675090,10775068,and 10975072the 973 National Major State Basic Research and Development of China under Grant No.2007CB815004+1 种基金CAS Knowledge Innovation Project KJCX2-SW-N02the Research Fund of Doctoral Point (RFDP) under Grant No.20070284016
文摘Relativistic mean-field theory and phase-shift analysis are combined together to investigate the elasticCoulomb scattering between electrons and unstable nuclei.Electron scattering at several different energies is studiedand compared,in order to see the energy dependence of electron-nucleus scattering.It is shown that electron scattering at200 MeV or 300 MeV can be used to reveal electron-nucleus scattering information around the first diffraction minimum-Shiftsin opposite directions are obtained for the first diffraction minima of the electron scattering off the ground andfirst excited states of ^(17)F with ^(16)O as reference,and similar effects are obtained for ^(18)Ne.Besides,some neutron-richN = 8 isotones are also studied.Results show that electron scattering will be very useful and important in studyingboth proton- and neutron-rich nuclei in the future.
文摘Incubation of camazepam [3-(N,N-dimethyl) carbamoyloxy-7-chloro-1- methyl-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one] with rat liver microsomes and cofactors produced a 3-(N-methyl-N-hydroxymethyl) carbamoyloxy derivative as the most abundant metabolite.This metabolite was thermally unstable and was isolated from a metabolite mixture by normal-phase High-Performance Liquid Chromatography.Its struc- ture was established by chemical ionization and ^(252)Cf plasma desorption time-of-flight mass spectral analyses.
文摘The adsorption state and catalytic properties of pepsin and acidic protease from microorganisms Asp. awamori and Asp. oryzae were studied in solid phase system (in presence of sorsilen, DEAE- and CM-cellulose). According to the results, adsorption capacity and catalytic activity of enzymes depend on the physical nature of surface groups of the solid phase. Changing the stability of enzymes in the system with solid phase is observed even the adsorption bond is less stable (in the case of DEAE- and CM-cellulose in acidic media). Injection to the medium ethanol, surfactants, sodium chloride and changing the temperature of the incubation medium could prevent the negative effects of the solid phases. When sorsilen is used as solid phase, pepsin and acidic protease from Asp. awamori suffer from high surface inactivation. Various surfactants influence adsorption state of enzymes differently. Non-ionic surfactants (Triton X-100) prevent adsorption and restore catalytic properties of enzymes.
文摘This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2+2 with an invariant manifold. The slow-fast system in R2+: has a 2-dimensional slow vector field and a 2-dimensional fast vector field. The fast vector field restricts a feasible region of the slow vector field strictly. In the case of the slow-fast system in R2+1 , that is, the fast vector field is l-dimension, it is classified according to its sign, because it gives only negative(-), positive(+) or zero sign. Then it is attractive, repulsive or stationary. On the other hand, in R2~2 , the fast vector field has combinatorial cases. It causes a complex state to analyze the system. First, we introduce a local model near the pseudo singular point on which we classify the fast vector field attractive(-,-), attractive-repulsive(-,+) or repulsive(+,+), simply as possible. We prove the existence of a 4-dimensional duck solution in the local model. Secondarily, we assume that the slow-fast system has an invariant manifold near the pseudo singular point. When the invariant manifold has a homoclinic point near the pseudo singular point, we show that the slow-fast sytem has a 4-dimensional duck solution having a relatively stable region.
文摘This study focused on the way that Adolescents with Transfusion- dependent thalassemia explained negative or positive events in their life (Attributional Styles). It is defined by three dimensions describing the cognitive appraisal of the events: internal-external, stable-unstable, and global-specific. With cross-sectional research design, the observations consist of 102 adolescents (48 males, 54 females) who diagnosed with Transfusion-dependent thalassemia (more than 50 times for blood transfusions) completed the measure of Attributional Styles and Anxiety Questionnaires. The correlations in the predicted directions among variables examine with Pearson product-moment correlation coefficients, t-test, and One-way ANOVA to ascertain a significant between the group differences on attributional factors and levels of anxiety symptoms. The results show that Adolescent samples with higher levels of anxiety revealed statistically significant relationship among three negative attributional dimensions (overall composite F = 4.5, p 〈 0.05; negative composite F = 4.99, p 〈 0.01; negative-internality F = 4.99 p 〈 0.01; negative-stability F = 3.42, p 〈 0.05 and negative-globality F = 3.77, p 〈 0.05). In addition, significant age- group differences were found for the total negative-globality (t = 2.05, p 〈 0.05) and negative- globality (t = -2.22, p 〈 0.05). These data are consistent with the reformulated learned helplessness model of depression. In finding, the individuals who attribute negative life events to internal, stable, and global causes will be more vulnerable to anxiety than those who make external, unstable, and specific attributions. Most interestingly, those adolescents more than 17 years evidence more negative-globality attfibutional style than group less than 16 years, and female adolescents may influence this pattern. These results suggest that targeting Adolescents with Transfusion-dependent thalassemia may be important for improving aspect of coping on psychological adjustment to their chronic illness.
基金The author would like to thank the Nature Science Foundation of China (Grant No.60627001)the Beijing Key Laboratory for Sensor(No.KM200810772001)
文摘In order to find out the influence of the instability of angular velocity of the rotating carrier itself on the stability of silicon micromachined gyroscope, the digital models for relative error of the high and low damping gyroscope's output signal are given respectively, based on the motion equations of the silicon micromachined gyroscope. Theory proves that the output signal error of the silicon micromachined sensor is mainly caused by the instability of damping factor and the angular velocity of the rotating carrier itself. The experiment result indicates that the error of proportionality coefficient of output voltage which is caused by the instability of the angular velocity of the rotating carrier itself reaches to 4.1 %. Theoretical demonstration and experimental verification show that the instability of angular velocity of the rotating carrier itself has an important effect on the stability of low damping silicon micromachined gyroscope.
文摘An experimental investigation is described for the characteristics of convective boiling flow instabilities in horizontally helically coiled tubes using a steam-water two-phase closed circulation test loop at pressure from 0.5 MPa to 3.5 MPa. Three kinds of oscillation are reported: density waves; pressure drop excursions; thermal fluctuations. We describe their dependence on main system parameters such as system pressure, mass flowrate, inlet subcooling, compressible volume and heat flux. Utilizing the experimental data together with conservation constraints, a dimensionless correlation is proposed for the occurrence of density waves.
文摘In order to clarify the natures of a rotating stall cell, the experimental investigation was carried out in a high specific-speed diagonal flow fan. The pressure field on the casing wall and the velocity fields at the rotor inlet and outlet were measured under rotating stall condition with a fast response pressure transducer and a single slant hot-wire probe, respectively. The data were processed using the “Double Phase-Locked Averaging (DPLA)”technique, which enabled to obtain the unsteady flow field with a rotating stall cell in the relative co-ordinate system fixed to the rotor. As a result, the structure and behavior of the rotating stall cell in a high specific-speed diagonal flow fan were shown.
基金supported by the National Natural Science Foundation of China(Grant No.41172180)Basic Research Funds from the Institute of Geology,China Earthquake Administration(Grant No.IGCEA1203)
文摘The meta-instable state(MIS)is the final stage before fault instability during stick-slip movement.Thus,identification of MIS is of great significance for assessing earthquake hazard in fault zones.A rock sample with a precut planar fault was loaded on a horizontally biaxial servo-controlled press machine to create stick-slip conditions.Digital images of the sample surface were taken by a high-speed camera at a rate of 1000 frames per second during the stick-slip motion and processed using a 2D digital image correlation method to obtain the displacement field.We define a synergism coefficient that describes the relative dispersion of the accumulative fault slip.The results reveal that:(1)a local pre-slip area spreads very slowly along the fault before the MIS develops.It extends at a higher but still slow speed during meta-instable state I(MIS-I).During the final^1.5%of MIS,in meta-instable state II(MIS-II),the local pre-slip area first extends at a speed of^0.9 m/s,and then expands out of the observed image area at a very high speed.These results indicate that the local pre-slip area transforms from a state of quasi-static extension in MIS-I to quasi-dynamic extension in MIS-II.(2)The synergism coefficient of the fault slip decreases to half of its original value in MIS-I and to a quarter of its original value in MIS-II.This continuous decrease of synergism coefficient indicates that the strengthening of fault slip synergism is a characteristic of MIS.(3)Furthermore,the unstable sliding stage includes three sliding processes:initial-,fast-,and adjusted-sliding.There are two pauses between the three sliding processes.
基金supported by the National Natural Science Foundation of China (Grant Nos.11072263,10727202)
文摘This article proposes a relay camera videometrics based method to convert an unstable measuring platform to a static reference to solve the problems of large error or invalidation caused by measuring platform instability in photogrammetric and videometric measurements.The method installs a relay camera on the unstable platform and captures images of a reference marker fixed on a static reference or vice versa to resolve the 3D movement of the unstable platform relative to the static reference,based on which it corrects the error of the measured results and thus eliminating the influence of the platform movement.It finds new and important applications for videometrics by making high-precision dynamic measurement possible on unstable platforms.Verification experiments and numerical simulations have proven its validity and practicability.
基金the Postdoctoral Scientific Foundation of China(No.20070410722)
文摘Boiling flow instability of nitrogen in a vertical tube is experimentally investigated in the present study. The experiments reveal that pressure has a significant effect on the characteristics of the heat flux-mass flux type boiling flow instability.First.the pressure has strong effects on both the developing time and the fluctuation amplitude.Especially increasing pressure leads to decrease the fluctuating amplitude of mass flux.Then,the mass flux evolving curves under different pressures feature out a shape like a leaf.The characteristics of the heat flux-mass flux type boiling flow instability under lower pressure are very complicated,however,with increasing pressure,this type of instability is gradually suppressed.
文摘The mechanism of the Weibel instability is investigated for dense magnetized plasmas. As we know, due to the electron velocity distribution, the Coulomb collision effect of electron-ion and the relativistic properties play an important role in such study. In this study an analytical expression for the growth rate and the condition of restricting the Weibel instability are derived for low-frequency limit. These calculations are done for the oscillation frequency dependence on the electron cyclotron frequency. It is shown that, the relativistic properties of the particle lead to increasing the growth rate of the instability. On the other hand the collision effects and background magnetic field try to decrease the growth rate by decreasing the temperature anisotropy and restricting the particles movement.