Based on analyzing the limit of Ziolkowski＇s bubble oscillation formulation,a new model with various physical factors is established to simulate air gun signatures fo marine seismic exploration.The practical effects ...Based on analyzing the limit of Ziolkowski＇s bubble oscillation formulation,a new model with various physical factors is established to simulate air gun signatures fo marine seismic exploration.The practical effects of physical factors,such as heat transfe across the bubble wall,air gun port throttling,vertical rise of the bubble,fluid viscosity,and the existence of the air gun body were all taken into account in the new model.Compared with Ziolkowski＇s model,the signatures simulated by the new model,with small peak amplitude and rapid decay of bubble oscillation,are more consistent with actual signatures The experiment analysis indicates：（1）gun port throttling controls the peak amplitude of ai gun pulse;（2）since the hydrostatic pressure decreases when the bubble rises,the bubble oscillation period changes;（3）heat transfer and fluid viscosity are the main factors tha explain the bubble oscillation damping.展开更多
Air gun arrays are often used in marine energy exploration and marine geological surveys.The study of the single bubble dynamics and multibubbles produced by air guns interacting with each other is helpful in understa...Air gun arrays are often used in marine energy exploration and marine geological surveys.The study of the single bubble dynamics and multibubbles produced by air guns interacting with each other is helpful in understanding pressure signals.We used the van der Waals air gun model to simulate the wavelets of a sleeve gun of various offsets and arrival angles.Several factors were taken into account,such as heat transfer,the thermodynamically open quasi-static system,the vertical rise of the bubble,and air gun post throttling.Marine vertical cables are located on the seafloor,but hydrophones are located in seawater and are far away from the air gun array vertically.This situation conforms to the acquisition conditions of the air gun far-field wavelet and thus avoids the problems of ship noise,ocean surges,and coupling.High-quality 3D wavelet data of air gun arrays were collected during a vertical cable test in the South China Sea in 2017.We proposed an evaluation method of multidimensional facial features,including zeropeak amplitude,peak-peak amplitude,bubble period,primary-to-bubble ratio,frequency spectrum,instantaneous amplitude,instantaneous phase,and instantaneous frequency,to characterize the 3D air gun wave field.The match between the facial features in the field and simulated data provides confidence for the use of the van der Waals air gun model to predict air gun wavelet and facial features to evaluate air gun array.展开更多
Air guns and rifles are usually considered to be harmless. Even though these firearms are categorized as toys, injuries with these are quite common in children and adolescents. The most common reason for these types o...Air guns and rifles are usually considered to be harmless. Even though these firearms are categorized as toys, injuries with these are quite common in children and adolescents. The most common reason for these types of injuries is accidents and negligence. In this case report we present a 17-year-old male, admitted to the emergency department with a 5 mm incision below his left eye. In the CT imaging a pellet was seen lodged in the cribriform plate. It pierced through the ethmoid sinus. The patient was admitted to the inpatient clinic and managed conservatively with antibiotherapy. A review of literature was performed to find out the best strategy to reach an optimized outcome and evaluate probable complications.展开更多
Penetrating abdominal trauma is the main cause of pancreatic lesions and delay in diagnosis or treatment can increase morbimortality. We present a case of acute necrohemorrhagic pancreatitis (ANHP) secondary to airgun...Penetrating abdominal trauma is the main cause of pancreatic lesions and delay in diagnosis or treatment can increase morbimortality. We present a case of acute necrohemorrhagic pancreatitis (ANHP) secondary to airgun injury associated with pulmonary embolism caused by the projectile in a 36 year old man. He underwent urgent surgery, appreciating pancreatic contusion but not visualizing the projectile, located by CT scan 3mm from the inferior vena cava. The patient underwent further surgery 48 hours later for necrosectomy and the insertion of an irrigation tube, due to ANHP after the migration of the projectile into the lung. This case underlines the clinical relevance of pancreatic lesion in patients with a penetrating abdominal trauma, the diagnostic difficulty and the surgical strategy, as well as the repercussions of the migration of a foreign body through the blood stream, crossing the right heart chambers and becoming lodged in the lung.展开更多
Air guns are important sources for marine seismic exploration. Far-field wavelet of air gun arrays, as a necessary parameter for pre-stack processing and source models, plays an important role during marine seismic da...Air guns are important sources for marine seismic exploration. Far-field wavelet of air gun arrays, as a necessary parameter for pre-stack processing and source models, plays an important role during marine seismic data processing and interpretation. When an air gun fires, it generates a series of air bubbles. Similar to onshore seismic exploration, the water forms a plastic fluid near the bubble; the farther the air gun is located from the measurement, the more steady and more accurately represented the wavelet will be. In practice, hydrophones should be placed more than 100 m from the air gun; however, traditional seismic cables cannot meet this requirement. On the other hand, vertical cables provide a viable solution to this problem. This study uses a vertical cable to receive wavelets from 38 air guns and data are collected offshore Southeast Qiong, where the water depth is over 1000 m. In this study, the wavelets measured using this technique coincide very well with the simulated wavelets and can therefore represent the real shape of the wavelets. This experiment fills a technology gap in China.展开更多
The fire distribution can be divided into weapon assignment and firing time scheduling. The criterion of weapon allocation is that a target with greater threat has higher priority. And the criterion of firing time sch...The fire distribution can be divided into weapon assignment and firing time scheduling. The criterion of weapon allocation is that a target with greater threat has higher priority. And the criterion of firing time scheduling is that a target can be damaged with the expected probability before a specific time. A fire distribution scheme and a program for the integrated missile-gun air defense system based on a criterion of earlier damage were presented. An example was taken to illustrate its effectiveness.展开更多
Compressed air is an integral utility part of industrial utility systems. Any improvement in compressed air system will lead to reduction in utility cost. The effectiveness of utilization side of compressed air is usu...Compressed air is an integral utility part of industrial utility systems. Any improvement in compressed air system will lead to reduction in utility cost. The effectiveness of utilization side of compressed air is usually dependent upon operator’s discretion. There are no performance testing methods available for testing existing end use equipments. A test apparatus for estimation of compressed air flow based on measurement of pressure reduction in a fixed volume cylinder in a given time is developed. The test apparatus is easy to build and simple to operate in an industrial environment. This can be used for measuring performance of any pneumatic end-use equipment and for benchmarking the performance. The test apparatus was used in a foundry for quantifying the performance of the old and new blow guns.展开更多
基金supported by the National 973 Program(Grant No.2007CB209608)National 863 Program(Grant No.2007AA06Z218)
文摘Based on analyzing the limit of Ziolkowski＇s bubble oscillation formulation,a new model with various physical factors is established to simulate air gun signatures fo marine seismic exploration.The practical effects of physical factors,such as heat transfe across the bubble wall,air gun port throttling,vertical rise of the bubble,fluid viscosity,and the existence of the air gun body were all taken into account in the new model.Compared with Ziolkowski＇s model,the signatures simulated by the new model,with small peak amplitude and rapid decay of bubble oscillation,are more consistent with actual signatures The experiment analysis indicates：（1）gun port throttling controls the peak amplitude of ai gun pulse;（2）since the hydrostatic pressure decreases when the bubble rises,the bubble oscillation period changes;（3）heat transfer and fluid viscosity are the main factors tha explain the bubble oscillation damping.
基金the National Natural Science Foundation of China(Nos.91958206,91858215)the National Key Research and Development Program Pilot Project(Nos.2018YFC1405901,2017YFC0307401)+1 种基金the Fundamental Research Funds for the Central Univer-sities(No.201964016)the Marine Geological Survey Program of China Geological Survey(No.DD20190819)。
文摘Air gun arrays are often used in marine energy exploration and marine geological surveys.The study of the single bubble dynamics and multibubbles produced by air guns interacting with each other is helpful in understanding pressure signals.We used the van der Waals air gun model to simulate the wavelets of a sleeve gun of various offsets and arrival angles.Several factors were taken into account,such as heat transfer,the thermodynamically open quasi-static system,the vertical rise of the bubble,and air gun post throttling.Marine vertical cables are located on the seafloor,but hydrophones are located in seawater and are far away from the air gun array vertically.This situation conforms to the acquisition conditions of the air gun far-field wavelet and thus avoids the problems of ship noise,ocean surges,and coupling.High-quality 3D wavelet data of air gun arrays were collected during a vertical cable test in the South China Sea in 2017.We proposed an evaluation method of multidimensional facial features,including zeropeak amplitude,peak-peak amplitude,bubble period,primary-to-bubble ratio,frequency spectrum,instantaneous amplitude,instantaneous phase,and instantaneous frequency,to characterize the 3D air gun wave field.The match between the facial features in the field and simulated data provides confidence for the use of the van der Waals air gun model to predict air gun wavelet and facial features to evaluate air gun array.
文摘Air guns and rifles are usually considered to be harmless. Even though these firearms are categorized as toys, injuries with these are quite common in children and adolescents. The most common reason for these types of injuries is accidents and negligence. In this case report we present a 17-year-old male, admitted to the emergency department with a 5 mm incision below his left eye. In the CT imaging a pellet was seen lodged in the cribriform plate. It pierced through the ethmoid sinus. The patient was admitted to the inpatient clinic and managed conservatively with antibiotherapy. A review of literature was performed to find out the best strategy to reach an optimized outcome and evaluate probable complications.
文摘Penetrating abdominal trauma is the main cause of pancreatic lesions and delay in diagnosis or treatment can increase morbimortality. We present a case of acute necrohemorrhagic pancreatitis (ANHP) secondary to airgun injury associated with pulmonary embolism caused by the projectile in a 36 year old man. He underwent urgent surgery, appreciating pancreatic contusion but not visualizing the projectile, located by CT scan 3mm from the inferior vena cava. The patient underwent further surgery 48 hours later for necrosectomy and the insertion of an irrigation tube, due to ANHP after the migration of the projectile into the lung. This case underlines the clinical relevance of pancreatic lesion in patients with a penetrating abdominal trauma, the diagnostic difficulty and the surgical strategy, as well as the repercussions of the migration of a foreign body through the blood stream, crossing the right heart chambers and becoming lodged in the lung.
基金supported by the National Natural Science Foundation of China (Nos. 41304096, 41230318)National High-tech R&D Program of China (863 Program) (No. 2013AA0925010201)+1 种基金Foundation of Ministry of Education of China (No. 20130132120014)the Fundamental Research Funds for the Central Universities (Nos. 1313017, 1362013)
文摘Air guns are important sources for marine seismic exploration. Far-field wavelet of air gun arrays, as a necessary parameter for pre-stack processing and source models, plays an important role during marine seismic data processing and interpretation. When an air gun fires, it generates a series of air bubbles. Similar to onshore seismic exploration, the water forms a plastic fluid near the bubble; the farther the air gun is located from the measurement, the more steady and more accurately represented the wavelet will be. In practice, hydrophones should be placed more than 100 m from the air gun; however, traditional seismic cables cannot meet this requirement. On the other hand, vertical cables provide a viable solution to this problem. This study uses a vertical cable to receive wavelets from 38 air guns and data are collected offshore Southeast Qiong, where the water depth is over 1000 m. In this study, the wavelets measured using this technique coincide very well with the simulated wavelets and can therefore represent the real shape of the wavelets. This experiment fills a technology gap in China.
基金Sponsored by Jiangsu Planned Project for Postdoctoral (0901014B)
文摘The fire distribution can be divided into weapon assignment and firing time scheduling. The criterion of weapon allocation is that a target with greater threat has higher priority. And the criterion of firing time scheduling is that a target can be damaged with the expected probability before a specific time. A fire distribution scheme and a program for the integrated missile-gun air defense system based on a criterion of earlier damage were presented. An example was taken to illustrate its effectiveness.
文摘Compressed air is an integral utility part of industrial utility systems. Any improvement in compressed air system will lead to reduction in utility cost. The effectiveness of utilization side of compressed air is usually dependent upon operator’s discretion. There are no performance testing methods available for testing existing end use equipments. A test apparatus for estimation of compressed air flow based on measurement of pressure reduction in a fixed volume cylinder in a given time is developed. The test apparatus is easy to build and simple to operate in an industrial environment. This can be used for measuring performance of any pneumatic end-use equipment and for benchmarking the performance. The test apparatus was used in a foundry for quantifying the performance of the old and new blow guns.
