Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this...Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.展开更多
BACKGROUND Hypocalcemia is highly common in hospitalized patients,especially in those with trauma,On the other hand,abnormal calcium metabolism is an important metabolic challenge;however,it is often neglected and unt...BACKGROUND Hypocalcemia is highly common in hospitalized patients,especially in those with trauma,On the other hand,abnormal calcium metabolism is an important metabolic challenge;however,it is often neglected and untreated,and certain factors may induce serious neurological and cardiovascular complications.AIM To retrospectively analyze the impact of hypocalcemia on the prognosis of patients with multiple traumas.METHODS The study was conducted from January 2020 to December 2021.Ninety-nine patients with multiple injuries were treated at the critical care medicine department of Fuyang People’s Hospital.The selected indicators included sex,age,and blood calcium and hematocrit levels.Many indicators were observed,including within 24 h of hospitalization,and the prognosis was collected after 28 d.Based on the blood calcium levels,the patients were divided into the following two groups:Normocalcemia and hypocalcemia.Of the 99 patients included,81 had normocalcemia,and 18 had hypocalcemia.Separate experiments were conducted for these two groups.RESULTS There was an association between serum calcium levels and the prognosis of patients with polytrauma.CONCLUSION Clinically,the prognosis of patients with multiple traumas can be preliminarily evaluated based on serum calcium levels.展开更多
Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for...Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for train to train rescue.In this paper,the longitudinal train dynamics of electric multiple units under rescue were analyzed by field and laboratory tests.The angling behavior of the brakinginduced coupler under compressed in-train forces was analyzed.A dynamic model for the train and draft gear system was developed considering accurate boundary limitations and braking characteristics.The safety indices and their limits for the coupled rescue train were defined.Thedynamic evaluations of different train to train rescue scenarios were analyzed.It is indicated that the coupler vertical rotation occurs during the emergency braking applied by the assisting train.The vertical force components of intrain forces lead to the carbody pitch behavior and even cause local destructions to the coupler system.The carbody pitch motion can arise the inference of in-train devices.Based on the safety evaluation of train and coupler system,the regulations for typical train to train rescue scenarios were formulated.展开更多
A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM...A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access （TDMA） technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network （OAN） with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system.展开更多
One of the most important responsibilities of a supply chain manager is to decide “how much” (or “many”) of inventory items to order and how to transport them. This paper presents four mixed-integer linear program...One of the most important responsibilities of a supply chain manager is to decide “how much” (or “many”) of inventory items to order and how to transport them. This paper presents four mixed-integer linear programming models to help supply chain managers make these decisions for multiple products subject to multiple constraints when suppliers offer quantity discounts and shippers offer freight discounts. Each model deals with one of the possible combinations of all-units, incremental quantity discounts, all-weight and incremental freight discounts. The models are based on a piecewise linear approximation of the number of orders function. They allow any number of linear constraints and determine if independent or common (fixed) cycle ordering has a lower total cost. Results of computational experiments on an example problem are also presented.展开更多
目的探讨急诊重症监护室(emergency intensive care unit,EICU)血流感染患者临床结局的风险因子,为临床决策提供依据。方法回顾性收集2019年1月至2023年4月我院就诊的141例EICU血流感染患者的病历资料及血培养记录,采用Logistic回归分...目的探讨急诊重症监护室(emergency intensive care unit,EICU)血流感染患者临床结局的风险因子,为临床决策提供依据。方法回顾性收集2019年1月至2023年4月我院就诊的141例EICU血流感染患者的病历资料及血培养记录,采用Logistic回归分析患者死亡的危险因素,运用Cox回归分析上述因素与患者生存时间和临床结局的关系。结果在141例EICU血流感染患者中,两种及以上细菌混合血流感染[比值比(OR)=5.68,95%置信区间(CI):1.20~26.98,P<0.05]及多重耐药菌血流感染(OR=6.39,95%CI:2.78~14.67,P<0.01)与患者死亡具有显著相关性;是否根据药敏结果及时调整用药[风险比(HR)=0.47,95%CI:0.30~0.74]和多重耐药菌血流感染(HR=2.02,95%CI:1.28~3.20)是EICU血流感染患者死亡的风险因子(P<0.01)。结论尽早采集血培养,明确感染病原菌,精准用药控制感染,可以有效降低患者的死亡率。展开更多
由于动车组车轮受加工装配及工况载荷等不确定因素的影响,车轮退化过程复杂,存在显著的个体差异及多个性能退化特征量,且多个退化特征量间相互耦合,仅考虑单个性能特征量难以全面反映其退化过程。因此,以轮缘和轮径作为车轮退化特征量,...由于动车组车轮受加工装配及工况载荷等不确定因素的影响,车轮退化过程复杂,存在显著的个体差异及多个性能退化特征量,且多个退化特征量间相互耦合,仅考虑单个性能特征量难以全面反映其退化过程。因此,以轮缘和轮径作为车轮退化特征量,通过随机化尺度参数表征车轮个体差异,采用Gamma过程和Copula函数建立二元相关退化模型,并根据赤池信息准则(Akaike Information Criterion, AIC)筛选Copula函数,得到可靠度解析式。基于某型动车组车轮实测磨耗数据,对车轮进行可靠性分析,同时通过车辆动力学模型进行仿真验证。结果显示:考虑二元相关时的可靠性结果比仅考虑一元退化更贴近车辆实际运行情况;根据动力学仿真结果体现了考虑个体差异的必要性,表明所提模型能够更准确地表征车轮退化过程,可为可靠性分析以及维修决策优化提供理论支撑。展开更多
文摘Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.
文摘BACKGROUND Hypocalcemia is highly common in hospitalized patients,especially in those with trauma,On the other hand,abnormal calcium metabolism is an important metabolic challenge;however,it is often neglected and untreated,and certain factors may induce serious neurological and cardiovascular complications.AIM To retrospectively analyze the impact of hypocalcemia on the prognosis of patients with multiple traumas.METHODS The study was conducted from January 2020 to December 2021.Ninety-nine patients with multiple injuries were treated at the critical care medicine department of Fuyang People’s Hospital.The selected indicators included sex,age,and blood calcium and hematocrit levels.Many indicators were observed,including within 24 h of hospitalization,and the prognosis was collected after 28 d.Based on the blood calcium levels,the patients were divided into the following two groups:Normocalcemia and hypocalcemia.Of the 99 patients included,81 had normocalcemia,and 18 had hypocalcemia.Separate experiments were conducted for these two groups.RESULTS There was an association between serum calcium levels and the prognosis of patients with polytrauma.CONCLUSION Clinically,the prognosis of patients with multiple traumas can be preliminarily evaluated based on serum calcium levels.
基金supported by the National Natural Science Foundation of China [No.U1334206]the National Key R&D Program of China [No.2016YFB1200500]
文摘Once operating trains are disabled on the railway lines,an efficient manner is to utilize the train for train rescue.Owning to the different train and coupler types,it is difficult to formulate uniform regulations for train to train rescue.In this paper,the longitudinal train dynamics of electric multiple units under rescue were analyzed by field and laboratory tests.The angling behavior of the brakinginduced coupler under compressed in-train forces was analyzed.A dynamic model for the train and draft gear system was developed considering accurate boundary limitations and braking characteristics.The safety indices and their limits for the coupled rescue train were defined.Thedynamic evaluations of different train to train rescue scenarios were analyzed.It is indicated that the coupler vertical rotation occurs during the emergency braking applied by the assisting train.The vertical force components of intrain forces lead to the carbody pitch behavior and even cause local destructions to the coupler system.The carbody pitch motion can arise the inference of in-train devices.Based on the safety evaluation of train and coupler system,the regulations for typical train to train rescue scenarios were formulated.
基金Supported by National Natural Science Foundation of China （61164013, U1334211, 51174091）, the Key Program of China Ministry of Railway （2011Z002-D）, and Natural Science Foundation of Jiangxi Province （20122BAB201021）
文摘A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access （TDMA） technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network （OAN） with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system.
文摘One of the most important responsibilities of a supply chain manager is to decide “how much” (or “many”) of inventory items to order and how to transport them. This paper presents four mixed-integer linear programming models to help supply chain managers make these decisions for multiple products subject to multiple constraints when suppliers offer quantity discounts and shippers offer freight discounts. Each model deals with one of the possible combinations of all-units, incremental quantity discounts, all-weight and incremental freight discounts. The models are based on a piecewise linear approximation of the number of orders function. They allow any number of linear constraints and determine if independent or common (fixed) cycle ordering has a lower total cost. Results of computational experiments on an example problem are also presented.
文摘目的探讨急诊重症监护室(emergency intensive care unit,EICU)血流感染患者临床结局的风险因子,为临床决策提供依据。方法回顾性收集2019年1月至2023年4月我院就诊的141例EICU血流感染患者的病历资料及血培养记录,采用Logistic回归分析患者死亡的危险因素,运用Cox回归分析上述因素与患者生存时间和临床结局的关系。结果在141例EICU血流感染患者中,两种及以上细菌混合血流感染[比值比(OR)=5.68,95%置信区间(CI):1.20~26.98,P<0.05]及多重耐药菌血流感染(OR=6.39,95%CI:2.78~14.67,P<0.01)与患者死亡具有显著相关性;是否根据药敏结果及时调整用药[风险比(HR)=0.47,95%CI:0.30~0.74]和多重耐药菌血流感染(HR=2.02,95%CI:1.28~3.20)是EICU血流感染患者死亡的风险因子(P<0.01)。结论尽早采集血培养,明确感染病原菌,精准用药控制感染,可以有效降低患者的死亡率。
文摘由于动车组车轮受加工装配及工况载荷等不确定因素的影响,车轮退化过程复杂,存在显著的个体差异及多个性能退化特征量,且多个退化特征量间相互耦合,仅考虑单个性能特征量难以全面反映其退化过程。因此,以轮缘和轮径作为车轮退化特征量,通过随机化尺度参数表征车轮个体差异,采用Gamma过程和Copula函数建立二元相关退化模型,并根据赤池信息准则(Akaike Information Criterion, AIC)筛选Copula函数,得到可靠度解析式。基于某型动车组车轮实测磨耗数据,对车轮进行可靠性分析,同时通过车辆动力学模型进行仿真验证。结果显示:考虑二元相关时的可靠性结果比仅考虑一元退化更贴近车辆实际运行情况;根据动力学仿真结果体现了考虑个体差异的必要性,表明所提模型能够更准确地表征车轮退化过程,可为可靠性分析以及维修决策优化提供理论支撑。
