Tracking load changes in a pressurized water reactor(PWR)with the help of an efficient core power control scheme in a nuclear power station is very important.The reason is that it is challenging to maintain a stable c...Tracking load changes in a pressurized water reactor(PWR)with the help of an efficient core power control scheme in a nuclear power station is very important.The reason is that it is challenging to maintain a stable core power according to the reference value within an acceptable tolerance for the safety of PWR.To overcome the uncertainties,a non-integer-based fractional order control method is demonstrated to control the core power of PWR.The available dynamic model of the reactor core is used in this analysis.Core power is controlled using a modified state feedback approach with a non-integer integral scheme through two different approximations,CRONE(Commande Robuste d’Ordre Non Entier,meaning Non-integer orderRobust Control)and FOMCON(non-integer order modeling and control).Simulation results are produced using MATLAB■program.Both non-integer results are compared with an integer order PI(Proportional Integral)algorithm to justify the effectiveness of the proposed scheme.Sate-spacemodel Core power control Non-integer control Pressurized water reactor PI controller CRONE FOMCON.展开更多
背景消化性溃疡(PUD)是消化系统常见疾病,中医药治疗作为PUD的有效治疗措施,但目前针对中医药治疗PUD的随机对照试验(RCT)中,方法学质量、结局指标的选择等存在较大局限性,给疗效评价、资料整合分析等带来一定挑战。目的本文系统梳理近1...背景消化性溃疡(PUD)是消化系统常见疾病,中医药治疗作为PUD的有效治疗措施,但目前针对中医药治疗PUD的随机对照试验(RCT)中,方法学质量、结局指标的选择等存在较大局限性,给疗效评价、资料整合分析等带来一定挑战。目的本文系统梳理近15年中医药干预PUD的RCT结局指标应用状况与试验设计要点,旨在为构建中医药治疗PUD核心指标集及优化临床试验设计提供参考依据。方法计算机检索中文数据库:中国知网、万方数据知识服务平台、维普网、中国生物医学文献服务系统,以及国际权威数据库:PubMed、Embase、Cochrane Library、Web of Science中关于中医药治疗PUD的RCT文献;检索时限为2010—2024年。对纳入文献进行Cochrane偏倚风险评估,并统计、归纳、分析相关结局指标。结果共纳入323篇RCT文献,34933例患者,单项研究样本量最大为498例,最小为40例,平均样本量为108例;171篇报告中医证型,其中使用频次最高为脾胃虚寒(31篇,18.13%);47篇采用纯中医治疗,276篇采用中西医结合治疗;治疗疗程多为4周(119次,36.84%);结局指标按照功能属性划分为6类,共报道了170种结局指标,总频次为1962次,其中使用频次较高的结局指标是临床总有效率(233次,11.88%)、幽门螺杆菌根除率(165次,8.41%)、不良反应(155次,7.90%);纳入文献偏倚风险评估多数为不明确。结论中医药治疗PUD的RCT尚存在中医辨证分型与疾病分期欠规范、方法学设计(盲法、分配隐藏)待完善、主次结局指标区分不明确、临床疗效标准未统一、结局指标测量时间差距大、中医证候/症状积分评分标准多元化、伦理注册待重视、安全性指标报告不规范等问题。建议积极开展中医药治疗PUD的核心指标集研究,优化完善方法学质量,为中医药治疗PUD的临床实践提供科学性、可靠性、实用性证据。展开更多
In situ pressure-preserved coring(IPP-Coring)technology is considered one of the most efficient methods for assessing resources.However,seal failure caused by the rotation of pressure controllers greatly affects the s...In situ pressure-preserved coring(IPP-Coring)technology is considered one of the most efficient methods for assessing resources.However,seal failure caused by the rotation of pressure controllers greatly affects the success of pressure coring.In this paper,a novel spherical-cylindrical shell pressure controller was proposed.The finite element analysis model was used to analyze the stress distribution and deformation characteristics of the pressure controller at different rotation angles.The seal failure mechanism caused by the rotation of the pressure controller was discussed.The stress deviation rate was defined to quantitatively characterize the stress concentration.Based on the test equipment designed in this laboratory,the ultimate bearing strength of the pressure controller was tested.The results show that the rotation of the valve cover causes an increase in the deformation on its lower side.Furthermore,the specific sealing pressure in the weak zone is greatly reduced by a statistically significant amount,resulting in seal failure.When the valve cover rotates 5°around the major axis,the stress deviation rate is-92.6%.To prevent rotating failure of the pressure controller,it is necessary to control the rotation angle of the valve cover within 1°around the major axis.The results of this research can help engineers reduce failure-related accidents,provide countermeasures for pressure coring,and contribute to the exploration and evaluation of deep oil and gas resources.展开更多
The existing active queue management （AQM） algorithm acts on subscribers and edge routers only, it does not support differentiate-serve （Diffserv） quality of service （QoS）, while the existing diffserv QoS has no...The existing active queue management （AQM） algorithm acts on subscribers and edge routers only, it does not support differentiate-serve （Diffserv） quality of service （QoS）, while the existing diffserv QoS has not considered the link capacities between edge routers and connected core routers. When a core router in a two layers’ network experiences congestion, the connected edge routers have no ability to adjust their access data rates. Thus, it is difficult to achieve the congestion control for the large scale network with many edge routers and core routers. To solve these problems, two difffserve AQM algorithms are proposed for the congestion control of multilayer network. One diffserv AQM algorithm implements fair link capacities of edge routers, and the other one implements unequal link capacities of edge routers, but it requires the core routers to have multi-queues buffers and Diffserv AQM to support. The proposed algorithms achieve the network congestion control by operating AQM parameters on the conditions of proposed three theorems for core and edge routers. The dynamic simulation results demonstrate the proposed control algorithms for core and edge routers to be valid.展开更多
基金This project was funded by the Deanship of Scientific Research(DSR),King Abdulaziz University,Jeddah,Saudi Arabia under grant no.(KEP-Msc-36-135-38).
文摘Tracking load changes in a pressurized water reactor(PWR)with the help of an efficient core power control scheme in a nuclear power station is very important.The reason is that it is challenging to maintain a stable core power according to the reference value within an acceptable tolerance for the safety of PWR.To overcome the uncertainties,a non-integer-based fractional order control method is demonstrated to control the core power of PWR.The available dynamic model of the reactor core is used in this analysis.Core power is controlled using a modified state feedback approach with a non-integer integral scheme through two different approximations,CRONE(Commande Robuste d’Ordre Non Entier,meaning Non-integer orderRobust Control)and FOMCON(non-integer order modeling and control).Simulation results are produced using MATLAB■program.Both non-integer results are compared with an integer order PI(Proportional Integral)algorithm to justify the effectiveness of the proposed scheme.Sate-spacemodel Core power control Non-integer control Pressurized water reactor PI controller CRONE FOMCON.
文摘背景消化性溃疡(PUD)是消化系统常见疾病,中医药治疗作为PUD的有效治疗措施,但目前针对中医药治疗PUD的随机对照试验(RCT)中,方法学质量、结局指标的选择等存在较大局限性,给疗效评价、资料整合分析等带来一定挑战。目的本文系统梳理近15年中医药干预PUD的RCT结局指标应用状况与试验设计要点,旨在为构建中医药治疗PUD核心指标集及优化临床试验设计提供参考依据。方法计算机检索中文数据库:中国知网、万方数据知识服务平台、维普网、中国生物医学文献服务系统,以及国际权威数据库:PubMed、Embase、Cochrane Library、Web of Science中关于中医药治疗PUD的RCT文献;检索时限为2010—2024年。对纳入文献进行Cochrane偏倚风险评估,并统计、归纳、分析相关结局指标。结果共纳入323篇RCT文献,34933例患者,单项研究样本量最大为498例,最小为40例,平均样本量为108例;171篇报告中医证型,其中使用频次最高为脾胃虚寒(31篇,18.13%);47篇采用纯中医治疗,276篇采用中西医结合治疗;治疗疗程多为4周(119次,36.84%);结局指标按照功能属性划分为6类,共报道了170种结局指标,总频次为1962次,其中使用频次较高的结局指标是临床总有效率(233次,11.88%)、幽门螺杆菌根除率(165次,8.41%)、不良反应(155次,7.90%);纳入文献偏倚风险评估多数为不明确。结论中医药治疗PUD的RCT尚存在中医辨证分型与疾病分期欠规范、方法学设计(盲法、分配隐藏)待完善、主次结局指标区分不明确、临床疗效标准未统一、结局指标测量时间差距大、中医证候/症状积分评分标准多元化、伦理注册待重视、安全性指标报告不规范等问题。建议积极开展中医药治疗PUD的核心指标集研究,优化完善方法学质量,为中医药治疗PUD的临床实践提供科学性、可靠性、实用性证据。
基金supported by the Program for Guangdong Introducing Innovative and Enterpreneurial Teams(No.2019ZT08G315)National Natural Science Foundation of China No.51827901 and U2013603
文摘In situ pressure-preserved coring(IPP-Coring)technology is considered one of the most efficient methods for assessing resources.However,seal failure caused by the rotation of pressure controllers greatly affects the success of pressure coring.In this paper,a novel spherical-cylindrical shell pressure controller was proposed.The finite element analysis model was used to analyze the stress distribution and deformation characteristics of the pressure controller at different rotation angles.The seal failure mechanism caused by the rotation of the pressure controller was discussed.The stress deviation rate was defined to quantitatively characterize the stress concentration.Based on the test equipment designed in this laboratory,the ultimate bearing strength of the pressure controller was tested.The results show that the rotation of the valve cover causes an increase in the deformation on its lower side.Furthermore,the specific sealing pressure in the weak zone is greatly reduced by a statistically significant amount,resulting in seal failure.When the valve cover rotates 5°around the major axis,the stress deviation rate is-92.6%.To prevent rotating failure of the pressure controller,it is necessary to control the rotation angle of the valve cover within 1°around the major axis.The results of this research can help engineers reduce failure-related accidents,provide countermeasures for pressure coring,and contribute to the exploration and evaluation of deep oil and gas resources.
基金supported by the Beijing Natural Science Foundation (4102050)NSFC-KOSEF Joint Research Project of China and Korea(60811140343), and the CDSN, GIST.
文摘The existing active queue management （AQM） algorithm acts on subscribers and edge routers only, it does not support differentiate-serve （Diffserv） quality of service （QoS）, while the existing diffserv QoS has not considered the link capacities between edge routers and connected core routers. When a core router in a two layers’ network experiences congestion, the connected edge routers have no ability to adjust their access data rates. Thus, it is difficult to achieve the congestion control for the large scale network with many edge routers and core routers. To solve these problems, two difffserve AQM algorithms are proposed for the congestion control of multilayer network. One diffserv AQM algorithm implements fair link capacities of edge routers, and the other one implements unequal link capacities of edge routers, but it requires the core routers to have multi-queues buffers and Diffserv AQM to support. The proposed algorithms achieve the network congestion control by operating AQM parameters on the conditions of proposed three theorems for core and edge routers. The dynamic simulation results demonstrate the proposed control algorithms for core and edge routers to be valid.
