This thesis discusses the earthquake reflecting ability of the observation well pattern system of Jiangsu Province,China,which has been digitally renovated,and probes into the cause of the major differences in the ear...This thesis discusses the earthquake reflecting ability of the observation well pattern system of Jiangsu Province,China,which has been digitally renovated,and probes into the cause of the major differences in the earthquake reflecting abilities of well holes at different measurement points.This is achieved through the analysis of the co-seismic responses to the Wenchuan(2008;Ms8.0,China)and Tohoku(2011;Ms9.0,Japan)earthquakes.We found that the co-seismic response of water level from regional well holes in Jiangsu Province was stronger than that of water temperature.The water-level co-seismic response follows a consistent law and is closely related to the earthquake magnitude.The co-seismic response of water temperature strongly varied among well points,and was more often manifested as a slow restorative change.The co-seismic responses also varied based on tectonic elements.The response in central and northern Jiangsu was weaker than that of southern Jiangsu,possibly due to the thicker loess cover layer in central Jiangsu which makes it less effective at capturing the micro-changes of stress-strain states relative to the hilly land in the south.The more complicated geological structure in southern Jiangsu makes it contribute to greater changes in the state of underground water after a minor disturbance.展开更多
Neurodegenerative disorders like Parkinson＇s disease （PD） or atypi- cal Parkinsonian syndromes including the different synucleinopa- thies and tauopathies are an important burden for patients, rela- tives, care pro...Neurodegenerative disorders like Parkinson＇s disease （PD） or atypi- cal Parkinsonian syndromes including the different synucleinopa- thies and tauopathies are an important burden for patients, rela- tives, care providers and incur mounting costs for the health care system in our aging society.展开更多
A pseudoplastic metal nanoparticle fluid （PMNF） is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key ...A pseudoplastic metal nanoparticle fluid （PMNF） is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key parameters, which influence the morphology of patterning, such as the radius of metal particles, the concentra- tion of metal particles, the Hamaker constant of the solvent, viscosity of the fluids and the evaporation velocity, are analyzed. Based on a two-sphere sintering model, the equations are derived, which represent the relationships between the relative shrinkage and radius of the metal particles, sintering temperature and time. The optimal parameters for the heat treatment are provided in nanoimprint.展开更多
1 Introduction The large clusters of Zn-Pb deposits in northeastern Yunnan,located in the southwestern margin of the Yangtze Block,are an important part of the Sichuan-YunnanGuizhou Pb-Zn Poly-metallic Metallogenic Tr...1 Introduction The large clusters of Zn-Pb deposits in northeastern Yunnan,located in the southwestern margin of the Yangtze Block,are an important part of the Sichuan-YunnanGuizhou Pb-Zn Poly-metallic Metallogenic Triangle Area展开更多
The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the hole...The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the holes. The effects of the perforated conic shroud on the vortex shedding pattern in the near wake was mainly investigated, as well as the time history of the drag and lift forces. In the investigated parameter space, three flow regimes were generally identified, corresponding to weak, moderate, and strong disturbance effects.In regime I, the wake can mainly be described by alternately shedding Kármán or Kármán-like vortices. In regime II, the spanwise vortices are obviously disturbed along the span due to the appearance of additional vorticity components and their interactions with the spanwise vortices, but still shed in synchronization along the spanwise direction. In regime III,the typical Kármán vortices partially or totally disappear,and some new vortex shedding patterns appear, such as-type, obliquely shedding, and crossed spanwise vortices with opposite sign. Corresponding to these complex vortex shedding patterns in the near wake, the fluid forces no longer oscillate regularly at a single vortex shedding frequency, but rather with a lower modulation frequency and multiple amplitudes. An overview of these flow regimes is presented.展开更多
The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built ...The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built and simulated in Matlab/Simulink to analyze the rotor vibration characteristics and the vibration reduction effect of the MRF damper.Based on the numerical simulation analysis,an optimizing control strategy using pattern search method was proposed and designed.The control system was constructed on a test rotor bench and experiment validations on the effectiveness of the proposed control strategy were conducted.Experimental results show that rotor vibration caused by unbalance can be well controlled whether in resonance region(70%)or in non-resonance region(30%).An irregular vibration amplitude jump can be suppressed with the optimization strategy.Furthermore,it is found that the rapidity of transient response and efficiency of optimizing technique depend on the pattern search step.The presented strategies and control system can be extended to multi-span(more than two or three spans)rotor system.It provides a powerful technical support for the extension and application in target and control for shafting vibration.展开更多
Petroleum production logging needs to determine the interpretation models first and flow pattern identification is the foundation, but traditional flow pattern identification methods have some limitations. In this pap...Petroleum production logging needs to determine the interpretation models first and flow pattern identification is the foundation, but traditional flow pattern identification methods have some limitations. In this paper, a new method of flow pattern identification in oil wells by electromagnetic image logging is proposed. First, the characteristics of gas-water and oil-water flow patterns in horizontal and vertical wellbores are picked up. Then, the continuous variation of the two phase flow pattern in the vertical and horizontal pipe space is discretized into continuous fluid distribution models in the pipeline section. Second, the electromagnetic flow image measurement responses of all the eight fluid distribution models are simulated and the characteristic vector of each response is analyzed in order to distinguish the fluid distribution models. Third, the time domain changes of the fluid distribution models in the pipeline section are used to identify the flow pattern. Finally, flow simulation experiments using electromagnetic flow image logging are operated and the experimental and simulated data are compared. The results show that the method can be used for flow pattern identification of actual electromagnetic image logging data.展开更多
Current work proposes a novel design methodology using curve-fitting approach for a non-axisymmetric airfoil convergent nozzle used in small-sized cryogenic turboexpander.The curves used for designing the nozzle are b...Current work proposes a novel design methodology using curve-fitting approach for a non-axisymmetric airfoil convergent nozzle used in small-sized cryogenic turboexpander.The curves used for designing the nozzle are based on a combination of fifth and third order curve at upper and lower surface respectively.Four different turbulence model such as k-ε,SST,BSL and SSG Reynolds stress turbulence model is used to visualize and compare the fluid flow characteristics and thermal behaviors at various cross-sections.It is interesting to observe that the Mach number obtained at the outlet of the nozzle is highest and temperature drop is maximum for SSG model under similar boundary conditions.It is also observed that the designed nozzle with curve fitting approach is appropriate for impulse type turbine with a small amount of reaction.The key feature of this implementation is to obtain subsonic velocity at the nozzle exit and reduce the irreversible losses through the nozzle,which can affect the performance of a turboexpander.展开更多
Background: Cerebrospinal fluid analysis is a very important tool in the diagnosis of bacterial meningitis in the new born. Bacterial meningitis is a potent cause of morbidity and mortality in the neonatal age group, ...Background: Cerebrospinal fluid analysis is a very important tool in the diagnosis of bacterial meningitis in the new born. Bacterial meningitis is a potent cause of morbidity and mortality in the neonatal age group, with a very high incidence of neurological complications. Aim: To identify the bacterial pathogens isolated from the cerebrospinal fluids of neonates at the University of Port Harcourt Teaching Hospital (UPTH) and their sensitivity patterns. This will assist the neonatologist in the choice of empirical antibiotic treatment. Study Design: Retrospective, descriptive, cross sectional study. Place and duration of study: University of Port Harcourt Teaching Hospital, from 1 January 2009 to 31 December 2014. Methods: Records of bacterial analysis of cerebrospinal fluid from neonates seen at the special care baby unit of the University of Port Harcourt Teaching Hospital with clinical suspicion of meningitis between 1 January 2009 and 31 December 2014 were retrieved from the microbiology record book. Data on patients age, sex, appearance of Cerebrospinal fluid, cell count, microscopy/gram stain, culture and antibiotic sensitivity were retrieved from laboratory record books and entered into a Microsoft? excel spread sheet and analysed using SPSS version 20.0. Results: One hundred and thirteen neonates: 70 (61.95%) of these patients were male while 43 (38.05%) were females. Only 1 (0.89%) was positive for culture yielding a growth of Escherichia coli which was sensitive to Imipenem, moderately sensitive to Ampicillin, Gentamicin, ceftazidime, cefuroxime, ciprofloxacin and Amoxicillinclavulanic acid. It was resistant to cefotaxime. 112 (99.11%) of the neonates had presumed neonatal meningitis while only 1 (0.89%) had proven neonatal meningitis. Conclusions: There is a low yield of organisms in cerebrospinal fluid of neonates at the University of Port Harcourt Teaching Hospital.展开更多
By means of flow visualization on the wall surface and three dimensional flow field numerical simulation for the turbine cascade with 3.6% relative tip clearance, characteristics of the wall flow of the turbine cascad...By means of flow visualization on the wall surface and three dimensional flow field numerical simulation for the turbine cascade with 3.6% relative tip clearance, characteristics of the wall flow of the turbine cascade with large tip clearance is analyzed. The flow pattern on the wall surface near the trailing edge is especially discussed in detail by numerical simulation. Results of the experimental and numerical simulation show that the flow near the cascade trailing edge is very complex, and the wall flow patterns near the upper and down trailing edges are clearly different due to the influence of blade tip clearance.展开更多
基金supported by the Scientific and Technological Support Project of Jiangsu Province(No.BS2007084)Seismic Technology Spark Project(No.XH12020)
文摘This thesis discusses the earthquake reflecting ability of the observation well pattern system of Jiangsu Province,China,which has been digitally renovated,and probes into the cause of the major differences in the earthquake reflecting abilities of well holes at different measurement points.This is achieved through the analysis of the co-seismic responses to the Wenchuan(2008;Ms8.0,China)and Tohoku(2011;Ms9.0,Japan)earthquakes.We found that the co-seismic response of water level from regional well holes in Jiangsu Province was stronger than that of water temperature.The water-level co-seismic response follows a consistent law and is closely related to the earthquake magnitude.The co-seismic response of water temperature strongly varied among well points,and was more often manifested as a slow restorative change.The co-seismic responses also varied based on tectonic elements.The response in central and northern Jiangsu was weaker than that of southern Jiangsu,possibly due to the thicker loess cover layer in central Jiangsu which makes it less effective at capturing the micro-changes of stress-strain states relative to the hilly land in the south.The more complicated geological structure in southern Jiangsu makes it contribute to greater changes in the state of underground water after a minor disturbance.
基金funded by the TRANSMED Kolleg Gottingen,which was supported by the Ministerium für Wissenschaft und Kultur,Niedersachsenfunded by the DFG-Center for Nanoscale Microscopy and Molecular Physiology of the Brain(CNMPB),Gottingen,Germany
文摘Neurodegenerative disorders like Parkinson＇s disease （PD） or atypi- cal Parkinsonian syndromes including the different synucleinopa- thies and tauopathies are an important burden for patients, rela- tives, care providers and incur mounting costs for the health care system in our aging society.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51175479 and 51475436the Education Department of Henan Province under Grant Nos 13A460725 and 2013GGJS-001
文摘A pseudoplastic metal nanoparticle fluid （PMNF） is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key parameters, which influence the morphology of patterning, such as the radius of metal particles, the concentra- tion of metal particles, the Hamaker constant of the solvent, viscosity of the fluids and the evaporation velocity, are analyzed. Based on a two-sphere sintering model, the equations are derived, which represent the relationships between the relative shrinkage and radius of the metal particles, sintering temperature and time. The optimal parameters for the heat treatment are provided in nanoimprint.
基金supported by the Funds for the program of the National Natural Science Foundation (Noes. 41572060, U1133602)Projects of YM Lab (2011)Innovation Team of Yunnan province and KMUST (2008,2012)
文摘1 Introduction The large clusters of Zn-Pb deposits in northeastern Yunnan,located in the southwestern margin of the Yangtze Block,are an important part of the Sichuan-YunnanGuizhou Pb-Zn Poly-metallic Metallogenic Triangle Area
基金supported by the National Key Scientific Instrument and Equipment Development Program of China (Grant 2011YQ120048)
文摘The flow past a circular-section cylinder with a conic shroud perforated with four holes at the peak was simulated numerically at Re = 100, considering two factors, viz.the angle of attack and the diameter of the holes. The effects of the perforated conic shroud on the vortex shedding pattern in the near wake was mainly investigated, as well as the time history of the drag and lift forces. In the investigated parameter space, three flow regimes were generally identified, corresponding to weak, moderate, and strong disturbance effects.In regime I, the wake can mainly be described by alternately shedding Kármán or Kármán-like vortices. In regime II, the spanwise vortices are obviously disturbed along the span due to the appearance of additional vorticity components and their interactions with the spanwise vortices, but still shed in synchronization along the spanwise direction. In regime III,the typical Kármán vortices partially or totally disappear,and some new vortex shedding patterns appear, such as-type, obliquely shedding, and crossed spanwise vortices with opposite sign. Corresponding to these complex vortex shedding patterns in the near wake, the fluid forces no longer oscillate regularly at a single vortex shedding frequency, but rather with a lower modulation frequency and multiple amplitudes. An overview of these flow regimes is presented.
基金Supported by the National Program on Key Basic Research Program(″973″Program)(2012CB026000)the Ph.D.Programs Foundation of Ministry of Education of China(20110010110009)
文摘The aim of this work is to analyze and design a control system for vibration reduction in a rotor system using a shear mode magnetorheological fluid(MRF)damper.A dynamic model of the MRF damper-rotor system was built and simulated in Matlab/Simulink to analyze the rotor vibration characteristics and the vibration reduction effect of the MRF damper.Based on the numerical simulation analysis,an optimizing control strategy using pattern search method was proposed and designed.The control system was constructed on a test rotor bench and experiment validations on the effectiveness of the proposed control strategy were conducted.Experimental results show that rotor vibration caused by unbalance can be well controlled whether in resonance region(70%)or in non-resonance region(30%).An irregular vibration amplitude jump can be suppressed with the optimization strategy.Furthermore,it is found that the rapidity of transient response and efficiency of optimizing technique depend on the pattern search step.The presented strategies and control system can be extended to multi-span(more than two or three spans)rotor system.It provides a powerful technical support for the extension and application in target and control for shafting vibration.
文摘Petroleum production logging needs to determine the interpretation models first and flow pattern identification is the foundation, but traditional flow pattern identification methods have some limitations. In this paper, a new method of flow pattern identification in oil wells by electromagnetic image logging is proposed. First, the characteristics of gas-water and oil-water flow patterns in horizontal and vertical wellbores are picked up. Then, the continuous variation of the two phase flow pattern in the vertical and horizontal pipe space is discretized into continuous fluid distribution models in the pipeline section. Second, the electromagnetic flow image measurement responses of all the eight fluid distribution models are simulated and the characteristic vector of each response is analyzed in order to distinguish the fluid distribution models. Third, the time domain changes of the fluid distribution models in the pipeline section are used to identify the flow pattern. Finally, flow simulation experiments using electromagnetic flow image logging are operated and the experimental and simulated data are compared. The results show that the method can be used for flow pattern identification of actual electromagnetic image logging data.
文摘Current work proposes a novel design methodology using curve-fitting approach for a non-axisymmetric airfoil convergent nozzle used in small-sized cryogenic turboexpander.The curves used for designing the nozzle are based on a combination of fifth and third order curve at upper and lower surface respectively.Four different turbulence model such as k-ε,SST,BSL and SSG Reynolds stress turbulence model is used to visualize and compare the fluid flow characteristics and thermal behaviors at various cross-sections.It is interesting to observe that the Mach number obtained at the outlet of the nozzle is highest and temperature drop is maximum for SSG model under similar boundary conditions.It is also observed that the designed nozzle with curve fitting approach is appropriate for impulse type turbine with a small amount of reaction.The key feature of this implementation is to obtain subsonic velocity at the nozzle exit and reduce the irreversible losses through the nozzle,which can affect the performance of a turboexpander.
文摘Background: Cerebrospinal fluid analysis is a very important tool in the diagnosis of bacterial meningitis in the new born. Bacterial meningitis is a potent cause of morbidity and mortality in the neonatal age group, with a very high incidence of neurological complications. Aim: To identify the bacterial pathogens isolated from the cerebrospinal fluids of neonates at the University of Port Harcourt Teaching Hospital (UPTH) and their sensitivity patterns. This will assist the neonatologist in the choice of empirical antibiotic treatment. Study Design: Retrospective, descriptive, cross sectional study. Place and duration of study: University of Port Harcourt Teaching Hospital, from 1 January 2009 to 31 December 2014. Methods: Records of bacterial analysis of cerebrospinal fluid from neonates seen at the special care baby unit of the University of Port Harcourt Teaching Hospital with clinical suspicion of meningitis between 1 January 2009 and 31 December 2014 were retrieved from the microbiology record book. Data on patients age, sex, appearance of Cerebrospinal fluid, cell count, microscopy/gram stain, culture and antibiotic sensitivity were retrieved from laboratory record books and entered into a Microsoft? excel spread sheet and analysed using SPSS version 20.0. Results: One hundred and thirteen neonates: 70 (61.95%) of these patients were male while 43 (38.05%) were females. Only 1 (0.89%) was positive for culture yielding a growth of Escherichia coli which was sensitive to Imipenem, moderately sensitive to Ampicillin, Gentamicin, ceftazidime, cefuroxime, ciprofloxacin and Amoxicillinclavulanic acid. It was resistant to cefotaxime. 112 (99.11%) of the neonates had presumed neonatal meningitis while only 1 (0.89%) had proven neonatal meningitis. Conclusions: There is a low yield of organisms in cerebrospinal fluid of neonates at the University of Port Harcourt Teaching Hospital.
文摘By means of flow visualization on the wall surface and three dimensional flow field numerical simulation for the turbine cascade with 3.6% relative tip clearance, characteristics of the wall flow of the turbine cascade with large tip clearance is analyzed. The flow pattern on the wall surface near the trailing edge is especially discussed in detail by numerical simulation. Results of the experimental and numerical simulation show that the flow near the cascade trailing edge is very complex, and the wall flow patterns near the upper and down trailing edges are clearly different due to the influence of blade tip clearance.
