The potential energy surfaces for butanone isomerization have been investigated by density function theory calculation. Six main reaction pathways are confirmed using the intrinsic reaction coordinate method, and the ...The potential energy surfaces for butanone isomerization have been investigated by density function theory calculation. Six main reaction pathways are confirmed using the intrinsic reaction coordinate method, and the corresponding isomerization products are 1-buten-2-ol, 2-buten-2-ol, butanal or 1-buten-l-ol, methyl 1-propenyl ether, methyl allyl ether, and ethyl vinyl ether, respectively. Among them, there are three pathways through butylene oxide, indicating butylene oxide is an important intermediate product during butanone isomer ization. The calculated vertical ionization energies of the reactant and its products are in a good agreement with the experimental values available. From the consideration for the relative energies Of transition states and the number of high-energy barriers we infer that the reaction pathway butanone-*l-buten-2-ol---2-buten-2-oi is the most competitive. The obtained results are informative for future studies on isomerization of ketone molecules.展开更多
We propose a sequential monomer reaction model for a two-species predator-prey system, in which the aggregates of either species can spontaneously produce or lose one monomer and meanwhile, a type-B aggregate can prey...We propose a sequential monomer reaction model for a two-species predator-prey system, in which the aggregates of either species can spontaneously produce or lose one monomer and meanwhile, a type-B aggregate can prey upon one monomer of a type-A aggregate when they meet. Using the mean-field rate equation approach, we analytically investigate the kinetic behavior of the system. The results show that the evolution of the system depends crucially on the details of the rate kernels. The aggregate size distribution of either species approaches the conventional or modified scaling form in most cases. Moreover, the total size of either species grows exponentially with time in some cases and asymptotically retains a constant quantity in other cases, while it decays with time and vanishes finally in the rest cases.展开更多
The classical elastic impedance (EI) inversion method, however, is based on the L2-norm misfit function and considerably sensitive to outliers, assuming the noise of the seismic data to be the Guassian-distribution....The classical elastic impedance (EI) inversion method, however, is based on the L2-norm misfit function and considerably sensitive to outliers, assuming the noise of the seismic data to be the Guassian-distribution. So we have developed a more robust elastic impedance inversion based on the Ll-norm misfit function, and the noise is assumed to be non-Gaussian. Meanwhile, some regularization methods including the sparse constraint regularization and elastic impedance point constraint regularization are incorporated to improve the ill-posed characteristics of the seismic inversion problem. Firstly, we create the Ll-norm misfit objective function of pre-stack inversion problem based on the Bayesian scheme within the sparse constraint regularization and elastic impedance point constraint regularization. And then, we obtain more robust elastic impedances of different angles which are less sensitive to outliers in seismic data by using the IRLS strategy. Finally, we extract the P-wave and S-wave velocity and density by using the more stable parameter extraction method. Tests on synthetic data show that the P-wave and S-wave velocity and density parameters are still estimated reasonable with moderate noise. A test on the real data set shows that compared to the results of the classical elastic impedance inversion method, the estimated results using the proposed method can get better lateral continuity and more distinct show of the gas, verifying the feasibility and stability of the method.展开更多
The fi rst arrival waveform inversion(FAWI)has a strong nonlinearity due to the objective function using L2 parametrization.When the initial velocity is not accurate,the inversion can easily fall into local minima.In ...The fi rst arrival waveform inversion(FAWI)has a strong nonlinearity due to the objective function using L2 parametrization.When the initial velocity is not accurate,the inversion can easily fall into local minima.In the full waveform inversion method,adding a cross-correlation function to the objective function can eff ectively reduce the nonlinearity of the inversion process.In this paper,the nonlinearity of this process is reduced by introducing the correlation objective function into the FAWI and by deriving the corresponding gradient formula.We then combine the first-arrival wave travel-time tomography with the FAWI to form a set of inversion processes.This paper uses the limited memory Broyden-Fletcher-Goldfarb-Shanno(L-BFGS)algorithm to improve the computational effi ciency of inversion and solve the problem of the low effi ciency of the FAWI method.The overthrust model and fi eld data test show that the method used in this paper can eff ectively reduce the nonlinearity of inversion and improve the inversion calculation effi ciency at the same time.展开更多
Low valence vanadium oxide(VO2-x) thin films were prepared on SiO2/Si substrates at room temperature by direct current facing targets reactive magnetron sputtering, and then proc- essed through rapid thermal annealing...Low valence vanadium oxide(VO2-x) thin films were prepared on SiO2/Si substrates at room temperature by direct current facing targets reactive magnetron sputtering, and then proc- essed through rapid thermal annealing. The effects of the annealing on the structure and phase transition property of VO2 were discussed. X-ray photoelectron spectroscopy, X-ray diffraction tech- nique and Fourier transform infrared spectroscopy were employed to study the phase composition and structure of the thin films. The resistance-temperature property was measured. The results show that VO2 thin film is obtained after annealed at 320 ℃ for 3 h, its phase transition tempera- ture is 56 ℃, and the resistance changes by more than 2 orders. The vanadium oxide thin films are applicable in thermochromic smart windows, and the deposition and annealing process is compatible with micro electromechanical system process.展开更多
Full waveform inversion( FWI) is a high resolution inversion method,which can reveal detailed information of the structure and lithology under complex geological background. It is limited by many kinds of noises when ...Full waveform inversion( FWI) is a high resolution inversion method,which can reveal detailed information of the structure and lithology under complex geological background. It is limited by many kinds of noises when the method applied to the real seismic data. Based on Huber function criterion,the objective function combinates the anti-noise of L1 norm and the stability of L2 norm in theory,the authors derive the gradient formula of the Huber function by using L-BFGS algorithm for FWI. The new method is proved by synthetic seismic data with the Gaussian noise and the impulse noise. Numerical test results show that L-BFGS algorithm is applied to the frequency domain FWI with the convergence speed and high calculation accuracy,and can effectively reduce computer memory usage; and the Huber function is more robust and stable than L2 norm even with the noises.展开更多
Oral lichen planus (OLP) is a chronic inflammatory disorder and premalignantlesion, of which the mechanisms are still obscure. In the present study, the expression levels of miR-96/182/183 cluster, miR-203, miR-375,...Oral lichen planus (OLP) is a chronic inflammatory disorder and premalignantlesion, of which the mechanisms are still obscure. In the present study, the expression levels of miR-96/182/183 cluster, miR-203, miR-375, and miR-769-5p in both tissues and exfoliative cells of OLP patients as well as healthy volunteers were detected, differentially expressed miRNAs were identified and their correlation with OLP was evaluated by a biplot method. Experimental results show that miR-203 is significantly up-regulated in patient lesion tissues in comparison to volunteer mucosa tissues. Moreover, the contra- dictory insignificant expression changes of miR-203 as well as miR-96/182/183 cluster in comparisons of exfoliative cell samples suggest that different cell compositions in OLP lesion have distinct miRNA regulation, which accords with the histological heterogeneity of OLP. Finally, biplot analyses indicate the expression of miR-203 and miR-96/182/183 cluster are positively correlated in patient lesions. These results provide miR-203 as a molecular indicator of heterogeneity of OLP, and also a potential diagnostic biomarker or therapeutic target that deserves further studies.展开更多
OBJECTIVE:To evaluate the effectiveness and safety of Shenmai injection for shock.METHODS: Randomized controlled trials(RCTs)that evaluated the therapeutic effect of Shenmai injection on shock(including septic shock, ...OBJECTIVE:To evaluate the effectiveness and safety of Shenmai injection for shock.METHODS: Randomized controlled trials(RCTs)that evaluated the therapeutic effect of Shenmai injection on shock(including septic shock, cardiogenic shock, hypovolemic shock, neurogenic shock and anaphylactic shock) were included in this analysis. The major electronic databases were searched until May 2015. The methodological quality of the trials was assessed according to the Cochrane Handbook. Review Manager 5.3 and Stata 12.0 software were applied for data analysis.RESULTS: Thirty RCTs involving 2038 participants were included. The methodological quality of the trials was generally passable. The combined use of Shenmai injection and conventional medicine was significantly more effective at managing shock compared to conventional medicine alone in the outcomes of total effective rate [risk ratio(RR 1.25,95% confidence interval(CI) 1.18 to 1.31] and mortality rate [risk difference(RD)-0.10, 95% CI-0.17 to-0.02]. Likewise, improvements were observed in other metrics. Three trials reported adverse events, but no trial reported serious adverse effects.CONCLUSION: Our results indicated the potential effectiveness of Shenmai injection combined with conventional medicine treatment for shock. However, further rigorously designed trials are needed to collect and weigh up all the evidence for the use of Shenmai injection.展开更多
文摘The potential energy surfaces for butanone isomerization have been investigated by density function theory calculation. Six main reaction pathways are confirmed using the intrinsic reaction coordinate method, and the corresponding isomerization products are 1-buten-2-ol, 2-buten-2-ol, butanal or 1-buten-l-ol, methyl 1-propenyl ether, methyl allyl ether, and ethyl vinyl ether, respectively. Among them, there are three pathways through butylene oxide, indicating butylene oxide is an important intermediate product during butanone isomer ization. The calculated vertical ionization energies of the reactant and its products are in a good agreement with the experimental values available. From the consideration for the relative energies Of transition states and the number of high-energy barriers we infer that the reaction pathway butanone-*l-buten-2-ol---2-buten-2-oi is the most competitive. The obtained results are informative for future studies on isomerization of ketone molecules.
基金supported by National Natural Science Foundation of China under Grant Nos.10775104 and 10305009Natural Science Foundation of Zhejiang Province of China under Grant No.102067
文摘We propose a sequential monomer reaction model for a two-species predator-prey system, in which the aggregates of either species can spontaneously produce or lose one monomer and meanwhile, a type-B aggregate can prey upon one monomer of a type-A aggregate when they meet. Using the mean-field rate equation approach, we analytically investigate the kinetic behavior of the system. The results show that the evolution of the system depends crucially on the details of the rate kernels. The aggregate size distribution of either species approaches the conventional or modified scaling form in most cases. Moreover, the total size of either species grows exponentially with time in some cases and asymptotically retains a constant quantity in other cases, while it decays with time and vanishes finally in the rest cases.
基金Projects(U1562215,41674130,41404088)supported by the National Natural Science Foundation of ChinaProjects(2013CB228604,2014CB239201)supported by the National Basic Research Program of China+1 种基金Projects(2016ZX05027004-001,2016ZX05002006-009)supported by the National Oil and Gas Major Projects of ChinaProject(15CX08002A)supported by the Fundamental Research Funds for the Central Universities,China
文摘The classical elastic impedance (EI) inversion method, however, is based on the L2-norm misfit function and considerably sensitive to outliers, assuming the noise of the seismic data to be the Guassian-distribution. So we have developed a more robust elastic impedance inversion based on the Ll-norm misfit function, and the noise is assumed to be non-Gaussian. Meanwhile, some regularization methods including the sparse constraint regularization and elastic impedance point constraint regularization are incorporated to improve the ill-posed characteristics of the seismic inversion problem. Firstly, we create the Ll-norm misfit objective function of pre-stack inversion problem based on the Bayesian scheme within the sparse constraint regularization and elastic impedance point constraint regularization. And then, we obtain more robust elastic impedances of different angles which are less sensitive to outliers in seismic data by using the IRLS strategy. Finally, we extract the P-wave and S-wave velocity and density by using the more stable parameter extraction method. Tests on synthetic data show that the P-wave and S-wave velocity and density parameters are still estimated reasonable with moderate noise. A test on the real data set shows that compared to the results of the classical elastic impedance inversion method, the estimated results using the proposed method can get better lateral continuity and more distinct show of the gas, verifying the feasibility and stability of the method.
基金supported by the Major Scientific and Technological Project of PetroChina (ZD2019-183-003)Project of National Natural Science Foundation of China (42074133)+1 种基金the Fundamental Research Funds for the Central Universities (19CX02056A)Project of State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development (33550000-21-FW0399-0009)
文摘The fi rst arrival waveform inversion(FAWI)has a strong nonlinearity due to the objective function using L2 parametrization.When the initial velocity is not accurate,the inversion can easily fall into local minima.In the full waveform inversion method,adding a cross-correlation function to the objective function can eff ectively reduce the nonlinearity of the inversion process.In this paper,the nonlinearity of this process is reduced by introducing the correlation objective function into the FAWI and by deriving the corresponding gradient formula.We then combine the first-arrival wave travel-time tomography with the FAWI to form a set of inversion processes.This paper uses the limited memory Broyden-Fletcher-Goldfarb-Shanno(L-BFGS)algorithm to improve the computational effi ciency of inversion and solve the problem of the low effi ciency of the FAWI method.The overthrust model and fi eld data test show that the method used in this paper can eff ectively reduce the nonlinearity of inversion and improve the inversion calculation effi ciency at the same time.
基金Natural Science Foundation of Tianjin(No.043100811)the Key Program of Natural Science Foundation of Tianjin(No.08JCZDJC17500)
文摘Low valence vanadium oxide(VO2-x) thin films were prepared on SiO2/Si substrates at room temperature by direct current facing targets reactive magnetron sputtering, and then proc- essed through rapid thermal annealing. The effects of the annealing on the structure and phase transition property of VO2 were discussed. X-ray photoelectron spectroscopy, X-ray diffraction tech- nique and Fourier transform infrared spectroscopy were employed to study the phase composition and structure of the thin films. The resistance-temperature property was measured. The results show that VO2 thin film is obtained after annealed at 320 ℃ for 3 h, its phase transition tempera- ture is 56 ℃, and the resistance changes by more than 2 orders. The vanadium oxide thin films are applicable in thermochromic smart windows, and the deposition and annealing process is compatible with micro electromechanical system process.
基金Supported by the National "863" Project(No.2014AA06A605)
文摘Full waveform inversion( FWI) is a high resolution inversion method,which can reveal detailed information of the structure and lithology under complex geological background. It is limited by many kinds of noises when the method applied to the real seismic data. Based on Huber function criterion,the objective function combinates the anti-noise of L1 norm and the stability of L2 norm in theory,the authors derive the gradient formula of the Huber function by using L-BFGS algorithm for FWI. The new method is proved by synthetic seismic data with the Gaussian noise and the impulse noise. Numerical test results show that L-BFGS algorithm is applied to the frequency domain FWI with the convergence speed and high calculation accuracy,and can effectively reduce computer memory usage; and the Huber function is more robust and stable than L2 norm even with the noises.
基金National Natural Science Foundation of China(Grant No.91029711)
文摘Oral lichen planus (OLP) is a chronic inflammatory disorder and premalignantlesion, of which the mechanisms are still obscure. In the present study, the expression levels of miR-96/182/183 cluster, miR-203, miR-375, and miR-769-5p in both tissues and exfoliative cells of OLP patients as well as healthy volunteers were detected, differentially expressed miRNAs were identified and their correlation with OLP was evaluated by a biplot method. Experimental results show that miR-203 is significantly up-regulated in patient lesion tissues in comparison to volunteer mucosa tissues. Moreover, the contra- dictory insignificant expression changes of miR-203 as well as miR-96/182/183 cluster in comparisons of exfoliative cell samples suggest that different cell compositions in OLP lesion have distinct miRNA regulation, which accords with the histological heterogeneity of OLP. Finally, biplot analyses indicate the expression of miR-203 and miR-96/182/183 cluster are positively correlated in patient lesions. These results provide miR-203 as a molecular indicator of heterogeneity of OLP, and also a potential diagnostic biomarker or therapeutic target that deserves further studies.
基金Supported by the Program for Zhejiang Leading Team of Science and Technology Innovation(No.2011R50021)Medical Research Program of Zhejiang Province(No.2015RCB011)
文摘OBJECTIVE:To evaluate the effectiveness and safety of Shenmai injection for shock.METHODS: Randomized controlled trials(RCTs)that evaluated the therapeutic effect of Shenmai injection on shock(including septic shock, cardiogenic shock, hypovolemic shock, neurogenic shock and anaphylactic shock) were included in this analysis. The major electronic databases were searched until May 2015. The methodological quality of the trials was assessed according to the Cochrane Handbook. Review Manager 5.3 and Stata 12.0 software were applied for data analysis.RESULTS: Thirty RCTs involving 2038 participants were included. The methodological quality of the trials was generally passable. The combined use of Shenmai injection and conventional medicine was significantly more effective at managing shock compared to conventional medicine alone in the outcomes of total effective rate [risk ratio(RR 1.25,95% confidence interval(CI) 1.18 to 1.31] and mortality rate [risk difference(RD)-0.10, 95% CI-0.17 to-0.02]. Likewise, improvements were observed in other metrics. Three trials reported adverse events, but no trial reported serious adverse effects.CONCLUSION: Our results indicated the potential effectiveness of Shenmai injection combined with conventional medicine treatment for shock. However, further rigorously designed trials are needed to collect and weigh up all the evidence for the use of Shenmai injection.