The distributed acoustic sensor(DAS)uses a single optical cable as the sensing unit,which can capture the acoustic and vibration signals along the optical cable in real-time.So it is suitable for monitoring downhole p...The distributed acoustic sensor(DAS)uses a single optical cable as the sensing unit,which can capture the acoustic and vibration signals along the optical cable in real-time.So it is suitable for monitoring downhole production activities in the process of oil and gas development.The authors applied the DAS system in a gas production well in the South China Sea for in situ monitoring of the whole wellbore for the first time and obtained the distributed acoustic signals along the whole wellbore.These signals can clearly distinguish the vertical section,curve section,and horizontal production section.The collected acoustic signal with the frequency of approximately 50 Hz caused by the electric submersible pump exhibit a signal-to-noise ratio higher than 27 dB.By analyzing the acoustic signals in the production section,it can be located the layers with high gas production rates.Once an accurate physical model is built in the future,the gas production profile will be obtained.In addition,the DAS system can track the trajectory of downhole tools in the wellbore to guide the operation.Through the velocity analysis of the typical signals,the type of fluids in the wellbore can be distinguished.The successful application of the system provides a promising whole wellbore acoustic monitoring tool for the production of marine gas hydrate,with a good application prospect.展开更多
Ⅰ. THE SCIENTIFIC BACKGROUND AND SIGNIFICANCE Abundant physical information about remote celestial bodies is contained in their optical spectra. The optical spectra of enormous amount of celestial bodies are critical...Ⅰ. THE SCIENTIFIC BACKGROUND AND SIGNIFICANCE Abundant physical information about remote celestial bodies is contained in their optical spectra. The optical spectra of enormous amount of celestial bodies are critical in astronomical research of wide field of view and large samples that concerns various frontiers in astronomy and astrophysics. Up to now, however, among the tens of billions of all kinds of celestial bodies recorded by imaging surveys, only a very little part (about one ten thousandth)展开更多
The China Fiber Inspection Bureau has announced that in 2007 it will reinforce the implementation of science, technologies, and standardization, and begin a project of constructing a fiber standardization demonstr... The China Fiber Inspection Bureau has announced that in 2007 it will reinforce the implementation of science, technologies, and standardization, and begin a project of constructing a fiber standardization demonstration area.……展开更多
The integrity of retinal ganglion cells is tightly associated with diabetic macular degeneration that leads to damage and death of retinal ganglion cells,affecting vision.The major clinical treatments for diabetic mac...The integrity of retinal ganglion cells is tightly associated with diabetic macular degeneration that leads to damage and death of retinal ganglion cells,affecting vision.The major clinical treatments for diabetic macular edema are anti-vascular endothelial growth factor drugs and laser photocoagulation.However,although the macular thickness can be normalized with each of these two therapies used alone,the vision does not improve in many patients.This might result from the incomplete recovery of retinal ganglion cell injury.Therefore,a prospective,non-randomized,controlled clinical trial was designed to investigate the effect of anti-vascular endothelial growth factor drugs combined with laser photocoagulation on the integrity of retinal ganglion cells in patients with diabetic macular edema and its relationship with vision recovery.In this trial,150 patients with diabetic macular edema will be equally divided into three groups according to therapeutic methods,followed by treatment with anti-vascular endothelial growth factor drugs,laser photocoagulation therapy,and their combination.All patients will be followed up for 12 months.The primary outcome measure is retinal ganglion cell-inner plexiform layer thickness at 12 months after treatment.The secondary outcome measures include retinal ganglion cell-inner plexiform layer thickness before and 1,3,6,and 9 months after treatment,retinal nerve fiber layer thickness,best-corrected visual acuity,macular area thickness,and choroidal thickness before and 1,3,6,9,and 12 months after treatment.Safety measure is the incidence of adverse events at 1,3,6,9,and 12 months after treatment.The study protocol hopes to validate the better efficacy and safety of the combined treatment in patients with diabetic macula compared with the other two monotherapies alone during the 12-month follow-up period.The trial is designed to focus on clarifying the time-effect relationship between imaging measures related to the integrity of retinal ganglion cells and best-corrected visual acuity.The trial protocol was approved by the Medical Ethics Committee of the Affiliated Hospital of Beihua University with approval No.(2023)(26)on April 25,2023,and was registered with the Chinese Clinical Trial Registry(registration number:ChiCTR2300072478,June 14,2023,protocol version:2.0).展开更多
随着信息技术的飞速发展,人们的日常工作与生活中开始融入智能、网络及云计算。而这些先进技术的实现需要依赖互联网主干网的接入,其在实际接入时,依然存在着瓶颈的情况。现阶段,该技术也是化解互联网主干网接入瓶颈的最佳方法。文章深...随着信息技术的飞速发展,人们的日常工作与生活中开始融入智能、网络及云计算。而这些先进技术的实现需要依赖互联网主干网的接入,其在实际接入时,依然存在着瓶颈的情况。现阶段,该技术也是化解互联网主干网接入瓶颈的最佳方法。文章深入分析光纤到户(Fiber To The Home,FTTH)技术的概念和基本特征,并提出了小区FTTH技术设计的有效策略和具体的案例。展开更多
基金jointly supported by the Science and Technology Program of Guangzhou (202103040003)the offshore NGHs production test projects under the Marine Geological Survey Program initiated by the China Geological Survey (DD20190226, DD20190218 and DD20221706)+2 种基金the Key Program of Marine Economy Development Special Foundation of Department of Natural Resources of Guangdong Province (GDNRC [2020] 045)the financial support from China Geological Survey (DD20221703)the National Natural Science Foundation of China (NSFC) (6210030553)。
文摘The distributed acoustic sensor(DAS)uses a single optical cable as the sensing unit,which can capture the acoustic and vibration signals along the optical cable in real-time.So it is suitable for monitoring downhole production activities in the process of oil and gas development.The authors applied the DAS system in a gas production well in the South China Sea for in situ monitoring of the whole wellbore for the first time and obtained the distributed acoustic signals along the whole wellbore.These signals can clearly distinguish the vertical section,curve section,and horizontal production section.The collected acoustic signal with the frequency of approximately 50 Hz caused by the electric submersible pump exhibit a signal-to-noise ratio higher than 27 dB.By analyzing the acoustic signals in the production section,it can be located the layers with high gas production rates.Once an accurate physical model is built in the future,the gas production profile will be obtained.In addition,the DAS system can track the trajectory of downhole tools in the wellbore to guide the operation.Through the velocity analysis of the typical signals,the type of fluids in the wellbore can be distinguished.The successful application of the system provides a promising whole wellbore acoustic monitoring tool for the production of marine gas hydrate,with a good application prospect.
文摘Ⅰ. THE SCIENTIFIC BACKGROUND AND SIGNIFICANCE Abundant physical information about remote celestial bodies is contained in their optical spectra. The optical spectra of enormous amount of celestial bodies are critical in astronomical research of wide field of view and large samples that concerns various frontiers in astronomy and astrophysics. Up to now, however, among the tens of billions of all kinds of celestial bodies recorded by imaging surveys, only a very little part (about one ten thousandth)
文摘 The China Fiber Inspection Bureau has announced that in 2007 it will reinforce the implementation of science, technologies, and standardization, and begin a project of constructing a fiber standardization demonstration area.……
基金supported by Science and Technology Research Project of Jilin Provincial Department of Education,No.JJKH20220072KJ(to XL)Science and Technology Development Program of Jilin Province,No.20200201495JC(to YL)。
文摘The integrity of retinal ganglion cells is tightly associated with diabetic macular degeneration that leads to damage and death of retinal ganglion cells,affecting vision.The major clinical treatments for diabetic macular edema are anti-vascular endothelial growth factor drugs and laser photocoagulation.However,although the macular thickness can be normalized with each of these two therapies used alone,the vision does not improve in many patients.This might result from the incomplete recovery of retinal ganglion cell injury.Therefore,a prospective,non-randomized,controlled clinical trial was designed to investigate the effect of anti-vascular endothelial growth factor drugs combined with laser photocoagulation on the integrity of retinal ganglion cells in patients with diabetic macular edema and its relationship with vision recovery.In this trial,150 patients with diabetic macular edema will be equally divided into three groups according to therapeutic methods,followed by treatment with anti-vascular endothelial growth factor drugs,laser photocoagulation therapy,and their combination.All patients will be followed up for 12 months.The primary outcome measure is retinal ganglion cell-inner plexiform layer thickness at 12 months after treatment.The secondary outcome measures include retinal ganglion cell-inner plexiform layer thickness before and 1,3,6,and 9 months after treatment,retinal nerve fiber layer thickness,best-corrected visual acuity,macular area thickness,and choroidal thickness before and 1,3,6,9,and 12 months after treatment.Safety measure is the incidence of adverse events at 1,3,6,9,and 12 months after treatment.The study protocol hopes to validate the better efficacy and safety of the combined treatment in patients with diabetic macula compared with the other two monotherapies alone during the 12-month follow-up period.The trial is designed to focus on clarifying the time-effect relationship between imaging measures related to the integrity of retinal ganglion cells and best-corrected visual acuity.The trial protocol was approved by the Medical Ethics Committee of the Affiliated Hospital of Beihua University with approval No.(2023)(26)on April 25,2023,and was registered with the Chinese Clinical Trial Registry(registration number:ChiCTR2300072478,June 14,2023,protocol version:2.0).
文摘随着信息技术的飞速发展,人们的日常工作与生活中开始融入智能、网络及云计算。而这些先进技术的实现需要依赖互联网主干网的接入,其在实际接入时,依然存在着瓶颈的情况。现阶段,该技术也是化解互联网主干网接入瓶颈的最佳方法。文章深入分析光纤到户(Fiber To The Home,FTTH)技术的概念和基本特征,并提出了小区FTTH技术设计的有效策略和具体的案例。
