Pre-stack depth migration velocity analysis is one of the key techniques influencing image quality. As for areas with a rugged surface and complex subsurface, conventional prestack depth migration velocity analysis co...Pre-stack depth migration velocity analysis is one of the key techniques influencing image quality. As for areas with a rugged surface and complex subsurface, conventional prestack depth migration velocity analysis corrects the rugged surface to a known datum or designed surface velocity model on which to perform migration and update the velocity. We propose a rugged surface tomographic velocity inversion method based on angle-domain common image gathers by which the velocity field can be updated directly from the rugged surface without static correction for pre-stack data and improve inversion precision and efficiency. First, we introduce a method to acquire angle-domain common image gathers （ADCIGs） in rugged surface areas and then perform rugged surface tornographic velocity inversion. Tests with model and field data prove the method to be correct and effective.展开更多
Through a summary of the results of past research on the time of the origin of hongqu(红曲,red yeast rice),a critical review is made of multiple pieces of published evidence supporting the various viewpoints that hong...Through a summary of the results of past research on the time of the origin of hongqu(红曲,red yeast rice),a critical review is made of multiple pieces of published evidence supporting the various viewpoints that hongqu originated from the Han,Wei,Jin,Tang,or Song dynasties.Based on a newly discovered textual comment by Kong Guangtao孔广陶(1832–1890)that rectified the mistake of mis-quoting“red wheat powder in Guazhou”(Guazhou hongzhi瓜州红)as“red yeast rice in Guazhou”(Guazhou hongqu瓜州红麯)in Entry into Learning(Chuxue ji初学记),a conclusion can be drawn that the evidence for a Han dynasty origin that has dominated for nearly forty years is not well-grounded,and proposes that Chinese hongqu originated in the Tang dynasty(618–907).展开更多
This paper demonstrates three species of Punctariaceae, newly-recorded in China. i.e. Desmotrichum balticum Kuetzing, Myriotrichia clavaeformis Harvey and Punctaria projecta Yamada.
The experiments of the onset of nucleate boiling using R134a as working fluid were conducted in vertical helically-coiled tubes. The experiments were carried out with a range of pressure from 450 to 850 kPa, inlet sub...The experiments of the onset of nucleate boiling using R134a as working fluid were conducted in vertical helically-coiled tubes. The experiments were carried out with a range of pressure from 450 to 850 kPa, inlet subcooling from 4.7 to 15.0℃, heat flux from 0.11 to 8.9 kW/m2 and mass flux from 218. 2 to 443. 7 kg/（ m2 · s ）. The heat flux, superheat and temperature undershoot at the ONB are analyzed in vertical helically-coiled tubes. Also, the effects of mass flux, system pressure, inlet subcooling and geometric parameters on the ONB are studied. The results demonstrate that the inception heat flux and superheat increase with increasing mass flux and inlet subcooling, but decrease with increasing system pressure and helix diameter. The pitch of the helical coil has a slight effect on the wall superheat and heat flux at the ONB. The correlation of heat flux at the ONB of subcooled flow boiling in helical coil is developed based on the experimental data, and it shows a good agreement with the experimental data.展开更多
During transcription initiation,RNA polymerase binds tightly to the promoter DNA defining the start of transcription,transcribes comparatively slowly,and frequently releases short transcripts(3-8 nucleotides)in a proc...During transcription initiation,RNA polymerase binds tightly to the promoter DNA defining the start of transcription,transcribes comparatively slowly,and frequently releases short transcripts(3-8 nucleotides)in a process called abortive cycling.Transitioning to elongation,the second phase of transcription,the polymerase dissociates from the promoter while RNA synthesis continues.Elongation is characterized by higher rates of transcription and tight binding to the RNA transcript.The RNA polymerase from enterophage T7 (T7 RNAP) has been used as a model to understand the mechanism of transcription in general,and the transition from initiation to elongation specifically.This single-subunit enzyme undergoes dramatic conformational changes during this transition to support the changing requirements of nucleic acid interactions while continuously maintaining polymerase function.Crystal structures,available of multiple stages of the initiation complex and of the elongation complex,combined with biochemical and biophysical data,offer molecular detail of the transition.Some of the crystal structures contain a variant of T7 RNAP where proline 266 is substituted by leucine.This variant shows less abortive products and altered timing of transition,and is a valuable tool to study these processes.The structural transitions from early to late initiation are well understood and are consistent with solution data.The timing of events and the structural intermediates in the transition from late initiation to elongation are less well understood,but the available data allows one to formulate testable models of the transition to guide further research.展开更多
The CD80 （B7-1） costimulatory molecule is expressed on the surface of B cells and its expression is transcriptionally upregulated upon stimuli. To identify the region of murine CD80 promoter that direct cell type sp...The CD80 （B7-1） costimulatory molecule is expressed on the surface of B cells and its expression is transcriptionally upregulated upon stimuli. To identify the region of murine CD80 promoter that direct cell type specific gene expression, four promoters construct of CD80 gene were generated with DNA fragments fused to the GFP reporter gene. In the present study, significant promoter activity was detected with all four promoter constructs only in the murine B lymphocyte. Further, the CD80 promoter region extending from -3,005 bp to ＋273 bp in relation to the previously reported transcription start site, was identified as tissue specific region. Interestingly, the shortest 700 bp （-427/＋273） of promoter fragment was sufficient to direct the CD80 gene expression. The level of CD80 expression was also found to be modulated by exogenous stimuli in B lymphocyte. Additionally, it was demonstrated that the CD80 gene expression is regulated at the level of transcription where the inducible CD80 gene transcript was detected in B lymphocyte with increasing time.展开更多
Grounded ship faces up exceptionally different stability forces unlike in her normal operating condition. This critical situation must be corrected as soon as can minimize hull stress, the risk of pollution and stabil...Grounded ship faces up exceptionally different stability forces unlike in her normal operating condition. This critical situation must be corrected as soon as can minimize hull stress, the risk of pollution and stability failure. Re-floating the ship need full understanding of the impact of ground reaction （R） on the ship buoyancy and stability. Re-floating the ship has different phases and there are several immediate actions that should be taken by ship＇s crew; one of these phases is re-calculation of ship stability conditions. In this paper, a guide to understanding the effect of the ground reaction （R）, determines the amount of ground pressure and its location. With consideration of the seabed form whether symmetric of asymmetric. Calculating the magnitude of the ground reaction （R） using different applicable methods, explaining the effect of using weight to re-float the ship by her own means, focusing on GM calculation after grounding.展开更多
基金sponsored by the National 863 Project(No.2009AA06Z206)the Self-governed Innovative Project of China University of Petroleum(No.11CX04010A)the Doctoral Fund of National Ministry of Education(No. 20110133120001)
文摘Pre-stack depth migration velocity analysis is one of the key techniques influencing image quality. As for areas with a rugged surface and complex subsurface, conventional prestack depth migration velocity analysis corrects the rugged surface to a known datum or designed surface velocity model on which to perform migration and update the velocity. We propose a rugged surface tomographic velocity inversion method based on angle-domain common image gathers by which the velocity field can be updated directly from the rugged surface without static correction for pre-stack data and improve inversion precision and efficiency. First, we introduce a method to acquire angle-domain common image gathers （ADCIGs） in rugged surface areas and then perform rugged surface tornographic velocity inversion. Tests with model and field data prove the method to be correct and effective.
基金sponsored by the Fujian Engineering and Research Center for Microbial Techniques of Red Yeast Rice,and copyedited by John Moffett。
文摘Through a summary of the results of past research on the time of the origin of hongqu(红曲,red yeast rice),a critical review is made of multiple pieces of published evidence supporting the various viewpoints that hongqu originated from the Han,Wei,Jin,Tang,or Song dynasties.Based on a newly discovered textual comment by Kong Guangtao孔广陶(1832–1890)that rectified the mistake of mis-quoting“red wheat powder in Guazhou”(Guazhou hongzhi瓜州红)as“red yeast rice in Guazhou”(Guazhou hongqu瓜州红麯)in Entry into Learning(Chuxue ji初学记),a conclusion can be drawn that the evidence for a Han dynasty origin that has dominated for nearly forty years is not well-grounded,and proposes that Chinese hongqu originated in the Tang dynasty(618–907).
文摘This paper demonstrates three species of Punctariaceae, newly-recorded in China. i.e. Desmotrichum balticum Kuetzing, Myriotrichia clavaeformis Harvey and Punctaria projecta Yamada.
基金The National Natural Science Foundation of China(No.50776055,51076084)the Natural Science Foundation of Shandong Province(No.ZR2016YL005)
文摘The experiments of the onset of nucleate boiling using R134a as working fluid were conducted in vertical helically-coiled tubes. The experiments were carried out with a range of pressure from 450 to 850 kPa, inlet subcooling from 4.7 to 15.0℃, heat flux from 0.11 to 8.9 kW/m2 and mass flux from 218. 2 to 443. 7 kg/（ m2 · s ）. The heat flux, superheat and temperature undershoot at the ONB are analyzed in vertical helically-coiled tubes. Also, the effects of mass flux, system pressure, inlet subcooling and geometric parameters on the ONB are studied. The results demonstrate that the inception heat flux and superheat increase with increasing mass flux and inlet subcooling, but decrease with increasing system pressure and helix diameter. The pitch of the helical coil has a slight effect on the wall superheat and heat flux at the ONB. The correlation of heat flux at the ONB of subcooled flow boiling in helical coil is developed based on the experimental data, and it shows a good agreement with the experimental data.
文摘During transcription initiation,RNA polymerase binds tightly to the promoter DNA defining the start of transcription,transcribes comparatively slowly,and frequently releases short transcripts(3-8 nucleotides)in a process called abortive cycling.Transitioning to elongation,the second phase of transcription,the polymerase dissociates from the promoter while RNA synthesis continues.Elongation is characterized by higher rates of transcription and tight binding to the RNA transcript.The RNA polymerase from enterophage T7 (T7 RNAP) has been used as a model to understand the mechanism of transcription in general,and the transition from initiation to elongation specifically.This single-subunit enzyme undergoes dramatic conformational changes during this transition to support the changing requirements of nucleic acid interactions while continuously maintaining polymerase function.Crystal structures,available of multiple stages of the initiation complex and of the elongation complex,combined with biochemical and biophysical data,offer molecular detail of the transition.Some of the crystal structures contain a variant of T7 RNAP where proline 266 is substituted by leucine.This variant shows less abortive products and altered timing of transition,and is a valuable tool to study these processes.The structural transitions from early to late initiation are well understood and are consistent with solution data.The timing of events and the structural intermediates in the transition from late initiation to elongation are less well understood,but the available data allows one to formulate testable models of the transition to guide further research.
文摘The CD80 （B7-1） costimulatory molecule is expressed on the surface of B cells and its expression is transcriptionally upregulated upon stimuli. To identify the region of murine CD80 promoter that direct cell type specific gene expression, four promoters construct of CD80 gene were generated with DNA fragments fused to the GFP reporter gene. In the present study, significant promoter activity was detected with all four promoter constructs only in the murine B lymphocyte. Further, the CD80 promoter region extending from -3,005 bp to ＋273 bp in relation to the previously reported transcription start site, was identified as tissue specific region. Interestingly, the shortest 700 bp （-427/＋273） of promoter fragment was sufficient to direct the CD80 gene expression. The level of CD80 expression was also found to be modulated by exogenous stimuli in B lymphocyte. Additionally, it was demonstrated that the CD80 gene expression is regulated at the level of transcription where the inducible CD80 gene transcript was detected in B lymphocyte with increasing time.
文摘Grounded ship faces up exceptionally different stability forces unlike in her normal operating condition. This critical situation must be corrected as soon as can minimize hull stress, the risk of pollution and stability failure. Re-floating the ship need full understanding of the impact of ground reaction （R） on the ship buoyancy and stability. Re-floating the ship has different phases and there are several immediate actions that should be taken by ship＇s crew; one of these phases is re-calculation of ship stability conditions. In this paper, a guide to understanding the effect of the ground reaction （R）, determines the amount of ground pressure and its location. With consideration of the seabed form whether symmetric of asymmetric. Calculating the magnitude of the ground reaction （R） using different applicable methods, explaining the effect of using weight to re-float the ship by her own means, focusing on GM calculation after grounding.
