Micro-RNAs(miRNAs) have been found to be implicated in a very wide range of physiological processes.This study was aimed to investigate the regulation of miRNA-429(miR-429) in gastric cancer cells on cell proliferatio...Micro-RNAs(miRNAs) have been found to be implicated in a very wide range of physiological processes.This study was aimed to investigate the regulation of miRNA-429(miR-429) in gastric cancer cells on cell proliferation and apoptosis.Quantitative PCR was employed to detect the expressions of miR-429 after eukaryotic expression plasmid of miR-429 and its inhibitor were transiently transfected into poorly differentiated human gastric can-cer cell line BGC823.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) reduction as-says were used to examine proliferation ability.Apoptosis was analyzed by flow cytometry after transfection.The results showed that 48 h after transfection,overexpression of miR-429 reached maximum efficiency.Compared with mock transfection,miR-429 inhibited tumor cell proliferation significantly(P < 0.05) at 48 h and 72 h.of Overexpression of miR-429 promoted tumor cell apoptosis when compared with mock transfected cells(P < 0.05).On the contrary,miR-429 inhibitor promoted tumor cell proliferation and inhibited apoptosis when compared with controls(P < 0.05).Our results suggested that miRNA-429 may serve as a tumor suppressor during tumorigenesis of gastric cancer and may be a potential gastric cancer therapeutic target.展开更多
We have used the ShenguangⅡlaser in third harmonic(351 nm)to investigate the emission of L-shell radiation in the 3.3–4.4 ke V range generated using thin foils of Sn coated onto a parylene substrate with irradiation...We have used the ShenguangⅡlaser in third harmonic(351 nm)to investigate the emission of L-shell radiation in the 3.3–4.4 ke V range generated using thin foils of Sn coated onto a parylene substrate with irradiation of order 1015 W cm-2 and nanosecond pulse duration.In our experiment,we have concentrated on assessing the emission on the non-laser irradiated side as this allows an experimental geometry relevant to experiments on photo-ionised plasmas where a secondary target must be placed close to the source,to achieve x-ray fluxes appropriate to astrophysical objects.Overall L-shell conversion efficiencies are estimated to be of order 1%,with little dependence on Sn thickness between 400 and 800 nm.展开更多
The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil.The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneou...The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil.The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneously generated magnetic field.The Cu I spectral lines at wavelengths of 510.5541,515.3235,and 521.8202 nm are detected and analyzed.The splittings of spectral lines are used to estimate the magnetic field strength at the coil center as∼31.4±15.7 T at a laser intensity of∼5.6310^(15) W/cm^(2),which agrees well with measurements using a B-dot probe.Some other plasma parameters of the central plasma disk are also studied.The temperature is evaluated from the Cu I spectral line intensity ratio,while the electron density is estimated from the Stark broadening effect.展开更多
Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Basic fibroblast growth factor (bFGF), which is highly expressed in developing tissues and malignant cells, regulates cell growth, differenti...Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Basic fibroblast growth factor (bFGF), which is highly expressed in developing tissues and malignant cells, regulates cell growth, differentiation, and migration. Its expression is essential for the progression and metastasis of HCC. This study aims to investigate the effects of bFGF on the expression of angiogenin, another growth factor, which plays an important role in tumor angiogenesis, and on cell proliferation in H7402 human hepatoma cells. The bFGF sense cDNA or antisense cDNA was stably transfected into H7402 cells. Genomic DNA PCR analysis demonstrated that human bFGF sense cDNA or antisense cDNA was inserted into the genome. Furthermore, the expression of bFGF and angiogenin was examined by RT-PCR and Western blot assays. MTT and colony formation assays were employed to determine cell proliferation. Stable bFGF over-expressing and under-expressing transfectants were successfully established. Expression of angiogenin was decreased in the over-expressing bFGF cells (sense transfectants) and was increased in the under-expressing bFGF cells (antisense transfectants). Cell proliferation increased in the bFGF sense transfectants and decreased in the bFGF antisense transfectants. These results demonstrated that the endogenous bFGF may not only negatively regulate the angiogenin expression but also contribute to the overall cell proliferation in H7402 human hepatoma cells. This study may be helpful in finding a potential therapeutic approach to HCC.展开更多
A novel method of initiating nuclear fusion reactions in a full plasma environment was suggested, and a proof-of-concept experiment was carried out with the D t D ! n t3 He reaction. In this new approach, two plasma j...A novel method of initiating nuclear fusion reactions in a full plasma environment was suggested, and a proof-of-concept experiment was carried out with the D t D ! n t3 He reaction. In this new approach, two plasma jets generated by high-intensity lasers collide headon-head. The center-of-mass energy of the nuclei increases accordingly, and therefore, reaction products can be significantly enhanced, especially in the sub-Coulomb barrier ranges. As a result of the fusion reaction, up to 7:6 105 neutrons had been observed. This new type of ‘‘plasma collider'' could provide an innovative tool to study nuclear reactions under astrophysical conditions.展开更多
As a promising new way to generate a controllable strong magnetic field, laser-driven magnetic coils have attracted interest in many research fields. In 2013, a kilotesla level magnetic field was achieved at the Gekk...As a promising new way to generate a controllable strong magnetic field, laser-driven magnetic coils have attracted interest in many research fields. In 2013, a kilotesla level magnetic field was achieved at the Gekko XⅡ laser facility with a capacitor–coil target. A similar approach has been adopted in a number of laboratories, with a variety of targets of different shapes. The peak strength of the magnetic field varies from a few tesla to kilotesla, with different spatiotemporal ranges. The differences are determined by the target geometry and the parameters of the incident laser. Here we present a review of the results of recent experimental studies of laser-driven magnetic field generation, as well as a discussion of the diagnostic techniques required for such rapidly changing magnetic fields. As an extension of the magnetic field generation, some applications are discussed.展开更多
We present laboratory measurement and theoretical analysis of silicon K-shell lines in plasmas produced by Shenguang II laser facility, and discuss the application of line ratios to diagnose the electron density and t...We present laboratory measurement and theoretical analysis of silicon K-shell lines in plasmas produced by Shenguang II laser facility, and discuss the application of line ratios to diagnose the electron density and temperature of laser plasmas.Two types of shots were carried out to interpret silicon plasma spectra under two conditions, and the spectra from 6.6 ?A to6.85 ?A were measured. The radiative-collisional code based on the flexible atomic code(RCF) is used to identify the lines, and it also well simulates the experimental spectra. Satellite lines, which are populated by dielectron capture and large radiative decay rate, influence the spectrum profile significantly. Because of the blending of lines, the traditional G value and R value are not applicable in diagnosing electron temperature and density of plasma. We take the contribution of satellite lines into the calculation of line ratios of He-α lines, and discuss their relations with the electron temperature and density.展开更多
The oil in the Jurassic Da'anzhai reservoirs in the Sichuan Basin is unconventional tight oil,which accumulated in or near source rocks,and did not experience extensive migration in a large-scale long distance.The...The oil in the Jurassic Da'anzhai reservoirs in the Sichuan Basin is unconventional tight oil,which accumulated in or near source rocks,and did not experience extensive migration in a large-scale long distance.The first submember,second submember and third submember of Da'anzhai Member are dominated by shell limestone which is widely and continuously distributed,and are typical near-source lacustrine shell limestone tight reservoirs.Complex lithology,multiple types of reservoir space and complicated pore structure are developed in these reservoirs.The effective reservoir space mainly includes micro-pores and micro-fractures with strong fabric selectivity.The petrophysics experiment reveals that the average connected matrix porosity of tight oil reservoir in Jurassic Da'anzhai Member is about 2.13%,lower than that of other tight oil reservoirs but higher than the average effective porosity(0.97%)from previous single alcohol-saturated method.According to production performance data,the Da'anzhai shell limestone reservoir is not a simple porous or fractured reservoir,but has complex porethroat-fracture association or storage-seepage mode.Because the development of fossil shells controls the development of micro-fractures,fluids are difficult to enter into but easy to escape from the reservoirs.Although the pore-throat is fine,the sorting is poor and the displacement pressure is high,the movable fluid saturation and mercury ejection efficiency of the reservoir in the Da'anzhai Member is only slightly lower than that of some storage-seepage modes,and higher than that of Oil-bearing Group 7 of Yanchang Formation in the Ordos Basin.The reservoir in the Da'anzhai Member is one of the few tight oil reservoirs with high natural productivity.The tight oil in the shell limestone of the Da'anzhai Member has great development potential,but its extensive and effective development also has some challenges,such as high seepage resistance of matrix and ineffective single development mode.The development mode of the Da'anzhai tight oil should draw lessons from the Bakken Formation in North America and Oil-bearing Gourp 7 of Yanchang Formation in the Ordos Basin,and thus,effective development technologies based on volume fracturing and fine operation for shell limestone tight oil in the Da'anzhai Member in Sichuan Basin are developed to realize the development of profit and scale.展开更多
The driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar res...The driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar research mostly depends on observations and theoretical models, laboratory experiments based on high-energy density facilities provide the third method for quantitatively comparing astrophysical observations and models with data achieved in experimental settings.In this article, we show laboratory modeling of solar flares and coronal mass ejections by constructing the magnetic reconnection system with two mutually approaching laser-produced plasmas circumfused of self-generated megagauss magnetic fields. Due to the Euler similarity between the laboratory and solar plasma systems, the present experiments demonstrate the morphological reproduction of flares and coronal mass ejections in solar observations in a scaled sense,and confirm the theory and model predictions about the current-sheet-born anomalous plasmoid as the initial stage of coronal mass ejections, and the behavior of moving-away plasmoid stretching the primary reconnected field lines into a secondary current sheet conjoined with two bright ridges identified as solar flares.展开更多
Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy...Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy cosmic rays. Until now, understanding these micro-processes is still a challenge despite rich astrophysical observation data have been obtained. Laboratory astrophysics, a new route to study the astrophysics, allows us to investigate them at similar extreme physical conditions in laboratory. Here we will review the recent progress of the collisionless shock experiments performed at SG-Ⅱ laser facility in China. The evolution of the electrostatic shocks and Weibel-type/filamentation instabilities are observed. Inspired by the configurations of the counter-streaming plasma flows, we also carry out a novel plasma collider to generate energetic neutrons relevant to the astrophysical nuclear reactions.展开更多
We present a parameter estimate for continua, and He-like triplets of the high resolution X-ray spectra with a Bayesian inference and a Markov Chain Monte Carlo(MCMC) tool. The method is applied for Vela X-1 with thre...We present a parameter estimate for continua, and He-like triplets of the high resolution X-ray spectra with a Bayesian inference and a Markov Chain Monte Carlo(MCMC) tool. The method is applied for Vela X-1 with three different orbital phases(φ), Eclipse, φ = 0.25, and φ = 0.5, which are adopted from the Chandra High-Energy Transmission Grating Spectrometer(HETGS). A parameterized two-component power-law model [Sako et al., Astrophys. J. 525, 921(1999)] and a multi-Gaussian model are applied to model these continua and He-like triplets, respectively. A uniform distribution over each parameter is used as the prior belief. Posterior probability distribution functions of parameters and the covariances among them are explored by using the MCMC method. The main advantages are(i) all model-based parameters are set to be free instead of artificially fixing some of the parameters during the data-model fitting;(ii) the contributions from satellite lines are considered;(iii) backgrounds are treated as a correction to the observation errors;and(iv) the confidence interval of each parameter is given. The fitted results show that the column density of scatter component(N_H^(scat)) varies from phase to phase, which imply a non-spherical structure of the stellar wind in Vela X-1.Moreover, the wind velocities derived from main lines of each set of He-like triplets show better self-consistency than those in previous publications, which could provide a reliable approach for the diagnostics of photoionized plasma in astrophysical objects and the laboratory.展开更多
基金supported by the National Natural Science Foundation of China(No.30973489)
文摘Micro-RNAs(miRNAs) have been found to be implicated in a very wide range of physiological processes.This study was aimed to investigate the regulation of miRNA-429(miR-429) in gastric cancer cells on cell proliferation and apoptosis.Quantitative PCR was employed to detect the expressions of miR-429 after eukaryotic expression plasmid of miR-429 and its inhibitor were transiently transfected into poorly differentiated human gastric can-cer cell line BGC823.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) reduction as-says were used to examine proliferation ability.Apoptosis was analyzed by flow cytometry after transfection.The results showed that 48 h after transfection,overexpression of miR-429 reached maximum efficiency.Compared with mock transfection,miR-429 inhibited tumor cell proliferation significantly(P < 0.05) at 48 h and 72 h.of Overexpression of miR-429 promoted tumor cell apoptosis when compared with mock transfected cells(P < 0.05).On the contrary,miR-429 inhibitor promoted tumor cell proliferation and inhibited apoptosis when compared with controls(P < 0.05).Our results suggested that miRNA-429 may serve as a tumor suppressor during tumorigenesis of gastric cancer and may be a potential gastric cancer therapeutic target.
基金supported by the UK Science and Technology Facilities Council,National Natural Science Foundation of China(No.11573040)Science Challenge Project(No.TZ2016005)The Royal Society International Exchange(No.IE161039).
文摘We have used the ShenguangⅡlaser in third harmonic(351 nm)to investigate the emission of L-shell radiation in the 3.3–4.4 ke V range generated using thin foils of Sn coated onto a parylene substrate with irradiation of order 1015 W cm-2 and nanosecond pulse duration.In our experiment,we have concentrated on assessing the emission on the non-laser irradiated side as this allows an experimental geometry relevant to experiments on photo-ionised plasmas where a secondary target must be placed close to the source,to achieve x-ray fluxes appropriate to astrophysical objects.Overall L-shell conversion efficiencies are estimated to be of order 1%,with little dependence on Sn thickness between 400 and 800 nm.
基金This work was supported in part by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA25010100,XDA25010300,and XDA25030100)the National Natural Science Foundation of China(Grant Nos.U1930107 and 11827807)the Japanese Ministry of Education,Science,Sports,and Culture through Grants-in-Aid,KAKENHI(Grant No.21H04454).
文摘The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil.The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneously generated magnetic field.The Cu I spectral lines at wavelengths of 510.5541,515.3235,and 521.8202 nm are detected and analyzed.The splittings of spectral lines are used to estimate the magnetic field strength at the coil center as∼31.4±15.7 T at a laser intensity of∼5.6310^(15) W/cm^(2),which agrees well with measurements using a B-dot probe.Some other plasma parameters of the central plasma disk are also studied.The temperature is evaluated from the Cu I spectral line intensity ratio,while the electron density is estimated from the Stark broadening effect.
基金supported by a grant (No. 20060923-02) from the Department of Science and Technology of Jilin Province, China
文摘Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Basic fibroblast growth factor (bFGF), which is highly expressed in developing tissues and malignant cells, regulates cell growth, differentiation, and migration. Its expression is essential for the progression and metastasis of HCC. This study aims to investigate the effects of bFGF on the expression of angiogenin, another growth factor, which plays an important role in tumor angiogenesis, and on cell proliferation in H7402 human hepatoma cells. The bFGF sense cDNA or antisense cDNA was stably transfected into H7402 cells. Genomic DNA PCR analysis demonstrated that human bFGF sense cDNA or antisense cDNA was inserted into the genome. Furthermore, the expression of bFGF and angiogenin was examined by RT-PCR and Western blot assays. MTT and colony formation assays were employed to determine cell proliferation. Stable bFGF over-expressing and under-expressing transfectants were successfully established. Expression of angiogenin was decreased in the over-expressing bFGF cells (sense transfectants) and was increased in the under-expressing bFGF cells (antisense transfectants). Cell proliferation increased in the bFGF sense transfectants and decreased in the bFGF antisense transfectants. These results demonstrated that the endogenous bFGF may not only negatively regulate the angiogenin expression but also contribute to the overall cell proliferation in H7402 human hepatoma cells. This study may be helpful in finding a potential therapeutic approach to HCC.
基金supported by the National Basic Research Program of China(2013CBA01501 and2013CB834401)the National Natural Science Foundation of China(11135012 and 11135005)+1 种基金the Doctoral Fund of Ministry of Education of China(20120073110065)Shanghai Municipal Science and Technology Commission(11DZ2260700)for the supports
文摘A novel method of initiating nuclear fusion reactions in a full plasma environment was suggested, and a proof-of-concept experiment was carried out with the D t D ! n t3 He reaction. In this new approach, two plasma jets generated by high-intensity lasers collide headon-head. The center-of-mass energy of the nuclei increases accordingly, and therefore, reaction products can be significantly enhanced, especially in the sub-Coulomb barrier ranges. As a result of the fusion reaction, up to 7:6 105 neutrons had been observed. This new type of ‘‘plasma collider'' could provide an innovative tool to study nuclear reactions under astrophysical conditions.
基金supported in part by the Science Challenge Project(No.TZ2016005)the CAS-JSPS Joint Research Program(External Cooperation Program of the BIC,Chinese Academy of Sciences,No.112111KYSB20160015)+1 种基金the National Natural Science Foundation of China(Nos.11520101003,11535001 and11861121001)the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB16010200 and XDB07030300)
文摘As a promising new way to generate a controllable strong magnetic field, laser-driven magnetic coils have attracted interest in many research fields. In 2013, a kilotesla level magnetic field was achieved at the Gekko XⅡ laser facility with a capacitor–coil target. A similar approach has been adopted in a number of laboratories, with a variety of targets of different shapes. The peak strength of the magnetic field varies from a few tesla to kilotesla, with different spatiotemporal ranges. The differences are determined by the target geometry and the parameters of the incident laser. Here we present a review of the results of recent experimental studies of laser-driven magnetic field generation, as well as a discussion of the diagnostic techniques required for such rapidly changing magnetic fields. As an extension of the magnetic field generation, some applications are discussed.
基金supported by the Science Challenge Project(No.TZ2016005)the National Basic Research Program of China(No.2013CBA01503)+1 种基金the National Natural Science Foundation of China(Nos.10905004,11220101002,and11622323)the Fundamental Research Funds for the Central Universities
文摘We present laboratory measurement and theoretical analysis of silicon K-shell lines in plasmas produced by Shenguang II laser facility, and discuss the application of line ratios to diagnose the electron density and temperature of laser plasmas.Two types of shots were carried out to interpret silicon plasma spectra under two conditions, and the spectra from 6.6 ?A to6.85 ?A were measured. The radiative-collisional code based on the flexible atomic code(RCF) is used to identify the lines, and it also well simulates the experimental spectra. Satellite lines, which are populated by dielectron capture and large radiative decay rate, influence the spectrum profile significantly. Because of the blending of lines, the traditional G value and R value are not applicable in diagnosing electron temperature and density of plasma. We take the contribution of satellite lines into the calculation of line ratios of He-α lines, and discuss their relations with the electron temperature and density.
基金supported by the project of the PetroChina Research Institute of Petroleum Exploration and Development(2016yj01)the National Science and Technology Major Project of China(No.2016ZX05046-003).
文摘The oil in the Jurassic Da'anzhai reservoirs in the Sichuan Basin is unconventional tight oil,which accumulated in or near source rocks,and did not experience extensive migration in a large-scale long distance.The first submember,second submember and third submember of Da'anzhai Member are dominated by shell limestone which is widely and continuously distributed,and are typical near-source lacustrine shell limestone tight reservoirs.Complex lithology,multiple types of reservoir space and complicated pore structure are developed in these reservoirs.The effective reservoir space mainly includes micro-pores and micro-fractures with strong fabric selectivity.The petrophysics experiment reveals that the average connected matrix porosity of tight oil reservoir in Jurassic Da'anzhai Member is about 2.13%,lower than that of other tight oil reservoirs but higher than the average effective porosity(0.97%)from previous single alcohol-saturated method.According to production performance data,the Da'anzhai shell limestone reservoir is not a simple porous or fractured reservoir,but has complex porethroat-fracture association or storage-seepage mode.Because the development of fossil shells controls the development of micro-fractures,fluids are difficult to enter into but easy to escape from the reservoirs.Although the pore-throat is fine,the sorting is poor and the displacement pressure is high,the movable fluid saturation and mercury ejection efficiency of the reservoir in the Da'anzhai Member is only slightly lower than that of some storage-seepage modes,and higher than that of Oil-bearing Group 7 of Yanchang Formation in the Ordos Basin.The reservoir in the Da'anzhai Member is one of the few tight oil reservoirs with high natural productivity.The tight oil in the shell limestone of the Da'anzhai Member has great development potential,but its extensive and effective development also has some challenges,such as high seepage resistance of matrix and ineffective single development mode.The development mode of the Da'anzhai tight oil should draw lessons from the Bakken Formation in North America and Oil-bearing Gourp 7 of Yanchang Formation in the Ordos Basin,and thus,effective development technologies based on volume fracturing and fine operation for shell limestone tight oil in the Da'anzhai Member in Sichuan Basin are developed to realize the development of profit and scale.
基金jointly supported by the National Natural Science Foundation of China (Nos. 11121504, 11074297, 11274152)the CAS project of KJCX2-YWT01the National Basic Research Program of China (No. 2007CB815101)
文摘The driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar research mostly depends on observations and theoretical models, laboratory experiments based on high-energy density facilities provide the third method for quantitatively comparing astrophysical observations and models with data achieved in experimental settings.In this article, we show laboratory modeling of solar flares and coronal mass ejections by constructing the magnetic reconnection system with two mutually approaching laser-produced plasmas circumfused of self-generated megagauss magnetic fields. Due to the Euler similarity between the laboratory and solar plasma systems, the present experiments demonstrate the morphological reproduction of flares and coronal mass ejections in solar observations in a scaled sense,and confirm the theory and model predictions about the current-sheet-born anomalous plasmoid as the initial stage of coronal mass ejections, and the behavior of moving-away plasmoid stretching the primary reconnected field lines into a secondary current sheet conjoined with two bright ridges identified as solar flares.
基金supported by the Science Challenge Project (No. TZ2016005)the National Basic Program of China (No. 2013CBA01501/03)+2 种基金the National Natural Science Foundation of China (Nos. 11503041, 11522326, 11622323, and 11573040)the Strategic Priority Research Program of the Chinese Academy of Sciences (Nos. XDB16010200 and XDB07030300)the Project Funded by China Postdoctoral Science Foundation (No. 2015M571124)
文摘Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy cosmic rays. Until now, understanding these micro-processes is still a challenge despite rich astrophysical observation data have been obtained. Laboratory astrophysics, a new route to study the astrophysics, allows us to investigate them at similar extreme physical conditions in laboratory. Here we will review the recent progress of the collisionless shock experiments performed at SG-Ⅱ laser facility in China. The evolution of the electrostatic shocks and Weibel-type/filamentation instabilities are observed. Inspired by the configurations of the counter-streaming plasma flows, we also carry out a novel plasma collider to generate energetic neutrons relevant to the astrophysical nuclear reactions.
基金supported by the Science Challenge Project(No.TZ2016005)the National Natural Science Foundation of China(NSFC)(Nos.11573040,11773033,11390371/2,and 11233004)support from the Recruitment Program of Global Youth Experts of China
文摘We present a parameter estimate for continua, and He-like triplets of the high resolution X-ray spectra with a Bayesian inference and a Markov Chain Monte Carlo(MCMC) tool. The method is applied for Vela X-1 with three different orbital phases(φ), Eclipse, φ = 0.25, and φ = 0.5, which are adopted from the Chandra High-Energy Transmission Grating Spectrometer(HETGS). A parameterized two-component power-law model [Sako et al., Astrophys. J. 525, 921(1999)] and a multi-Gaussian model are applied to model these continua and He-like triplets, respectively. A uniform distribution over each parameter is used as the prior belief. Posterior probability distribution functions of parameters and the covariances among them are explored by using the MCMC method. The main advantages are(i) all model-based parameters are set to be free instead of artificially fixing some of the parameters during the data-model fitting;(ii) the contributions from satellite lines are considered;(iii) backgrounds are treated as a correction to the observation errors;and(iv) the confidence interval of each parameter is given. The fitted results show that the column density of scatter component(N_H^(scat)) varies from phase to phase, which imply a non-spherical structure of the stellar wind in Vela X-1.Moreover, the wind velocities derived from main lines of each set of He-like triplets show better self-consistency than those in previous publications, which could provide a reliable approach for the diagnostics of photoionized plasma in astrophysical objects and the laboratory.
