The central trinomial coefficient T_(n)denotes the coefficient of x^(n)in the expansion of(1+x+x^(2))^(n).We prove a congruence related to the sums of the central trinomial coefficient and the central binomial coeffic...The central trinomial coefficient T_(n)denotes the coefficient of x^(n)in the expansion of(1+x+x^(2))^(n).We prove a congruence related to the sums of the central trinomial coefficient and the central binomial coefficient,which was conjectured by Z.-W.Sun.展开更多
The Underwater Communication Link(UCL)is a crucial component of Underwater Wireless Optical Communication(UWOC)systems,requiring optimised design to mitigate the high power attenuation inherent in seawater.To ensure t...The Underwater Communication Link(UCL)is a crucial component of Underwater Wireless Optical Communication(UWOC)systems,requiring optimised design to mitigate the high power attenuation inherent in seawater.To ensure the reliability of an optimal UCL design,it is essential to account for the three primary scattering regimes:forward scattering(FSC),backward scattering(BSC),and isotropic scattering(ISC)in seawater channels.This study introduces a new photon-tracking model based on a discrete equation,facilitating Monte Carlo Simulation(MCS)to evaluate how different scattering regimes influence received photon distribution.Three distinct Scattering Regime Contribution Weight(SRCW)probability sets were employed,each representing different UCL operational configurations dominated by specific scattering regimes.The proposed modeling approach enables a comprehensive assessment of the temporal characteristics of received optical pulses,channel loss,and time spread-ultimately defining the optimal UCL design parameters.The key findings of this study include:(1)Enhancing the FSC regime dominance leads to a quasi-light waveguide effect over link spans and small Fields of View(FOV)<25°,significantly improving channel performance in Harbor seawater compared to Coastal seawater.(2)A well-designed UCL with a small FOV(<25°)can minimise channel loss and time spread,ensuring high capacity and efficient performance in both Coastal and Harbor seawaters.(3)When BSC and ISC contributions exceed FSC dominance,the received optical pulse undergoes significant temporal broadening,particularly for larger FOV angles(>25°)and extended link spans.(4)The developed novel MCS-based discrete equation provides a simple yet robust model for simulating photon propagation in both homogeneous and inhomogeneous underwater channels.These insights contribute to developing more efficient and reliable UCL designs with military standards by enhancing UWOC system performance over a longer linkspan for a given limited optical power across various underwater environments.展开更多
Although body mass index(BMI)is widely used as a simple tool to assess obesity,it has certain limitations and inaccuracies.It is known that visceral adipose tissue is closely related to cardiometabolic risks and all-c...Although body mass index(BMI)is widely used as a simple tool to assess obesity,it has certain limitations and inaccuracies.It is known that visceral adipose tissue is closely related to cardiometabolic risks and all-cause mortality;however,precise measurement methods for visceral fat(magnetic resonance imaging and computed tomography)cannot be widely used.Thus,simple but accurate alternatives are valuable.Studies have shown that waist circumference-to-height ratio(WHtR)might be a superior and more accurate variable in assessing central or visceral adiposity as well as predicting risks of diabetes and other cardiometabolic diseases.Furthermore,WHtR cutoff values can be consistent across different races,age,and genders,making it a universal metric worth promoting and applying.展开更多
Coordinated taxiing planning for multiple aircraft on flight deck is of vital importance which can dramatically improve the dispatching efficiency.In this paper,first,the coordinated taxiing path planning problem is t...Coordinated taxiing planning for multiple aircraft on flight deck is of vital importance which can dramatically improve the dispatching efficiency.In this paper,first,the coordinated taxiing path planning problem is transformed into a centralized optimal control problem where collision-free conditions and mechanical limits are considered.Since the formulated optimal control problem is of large state space and highly nonlinear,an efficient hierarchical initialization technique based on the Dubins-curve method is proposed.Then,a model predictive controller is designed to track the obtained reference trajectory in the presence of initial state error and external disturbances.Numerical experiments demonstrate that the proposed“offline planningþonline tracking”framework can achieve efficient and robust coordinated taxiing planning and tracking even in the presence of initial state error and continuous external disturbances.展开更多
How to make use of limited onboard resources for complex and heavy space tasks has attracted much attention.With the continuous improvement on satellite payload capacity and the increasing complexity of observation re...How to make use of limited onboard resources for complex and heavy space tasks has attracted much attention.With the continuous improvement on satellite payload capacity and the increasing complexity of observation requirements,the importance of satellite autonomous task scheduling research has gradually increased.This article first gives the problem description and mathematical model for the satellite autonomous task scheduling and then follows the steps of"satellite autonomous task scheduling,centralized autonomous collaborative task scheduling architecture,distributed autonomous collaborative task scheduling architecture,solution algorithm".Finally,facing the complex and changeable environment situation,this article proposes the future direction of satellite autonomous task scheduling.展开更多
在单因素试验基础上,通过Plackett-Burman试验筛选及中心组合设计试验优化超声时间、超声温度和混酸用量三个因素对超声辅助提取人发中铅的影响。由响应面法建立二次回归模型得到最佳超声条件为:超声时间16 min,超声温度56℃,混酸体积6....在单因素试验基础上,通过Plackett-Burman试验筛选及中心组合设计试验优化超声时间、超声温度和混酸用量三个因素对超声辅助提取人发中铅的影响。由响应面法建立二次回归模型得到最佳超声条件为:超声时间16 min,超声温度56℃,混酸体积6.50 m L。方法的相对标准偏差(RSD)为3.18%。检出限为0.80μg·L^(-1),定量限为2.7μg·L^(-1)。t检验结果表明超声提取法和湿消解法之间无显著性差异,因此用超声波辅助-原子吸收光谱法测定人发中的铅方法可行,且超声提取法耗时短、试剂用量少。展开更多
目的探讨5F鞘组在经外周静脉穿刺置入中心静脉导管(peripherally inserted central catheter,PICC)中临床应用的效果。方法回顾性分析并总结2012年12月至2013年2月哈尔滨医科大学附属第一医院收治的应用5F鞘组10例行PICC患者的临床资料...目的探讨5F鞘组在经外周静脉穿刺置入中心静脉导管(peripherally inserted central catheter,PICC)中临床应用的效果。方法回顾性分析并总结2012年12月至2013年2月哈尔滨医科大学附属第一医院收治的应用5F鞘组10例行PICC患者的临床资料。结果 10例患者均顺利完成PICC,有2例患者术后出现静脉炎,其余患者均未发生严重的并发症。结论静脉穿刺条件差的患者应用5F鞘组行PICC导管有利于提高置管成功率。展开更多
金枪鱼渔业区域性管理组织主要有大西洋金枪鱼养护国际委员会（International Commission for the Conservation of Atlantic Tunas-ICCAT）,印度洋金枪鱼委员会（Indian Ocean Tuna Commission -IOTC）, 中西太平洋渔业委员会（Western...金枪鱼渔业区域性管理组织主要有大西洋金枪鱼养护国际委员会（International Commission for the Conservation of Atlantic Tunas-ICCAT）,印度洋金枪鱼委员会（Indian Ocean Tuna Commission -IOTC）, 中西太平洋渔业委员会（Western and Central Pacific Fisheries Commission -WCPFC）,南方蓝鳍金枪鱼养护委员会（Commission for the Conservation of Southern Blue-fin Tuna- CCSBT）等5个。展开更多
基金National Natural Science Foundation of China(11971222,12071208)Jiangsu Qinglan ProjectProject of Guangzhou Huashang College(2022HSDS27)。
文摘The central trinomial coefficient T_(n)denotes the coefficient of x^(n)in the expansion of(1+x+x^(2))^(n).We prove a congruence related to the sums of the central trinomial coefficient and the central binomial coefficient,which was conjectured by Z.-W.Sun.
基金The Deanship of Scientific Research(DSR)at King Abdulaziz University(KAU),Jeddah,Saudi Arabia,has funded this project under Grant No.(KEP-PhD:72-130-1443).
文摘The Underwater Communication Link(UCL)is a crucial component of Underwater Wireless Optical Communication(UWOC)systems,requiring optimised design to mitigate the high power attenuation inherent in seawater.To ensure the reliability of an optimal UCL design,it is essential to account for the three primary scattering regimes:forward scattering(FSC),backward scattering(BSC),and isotropic scattering(ISC)in seawater channels.This study introduces a new photon-tracking model based on a discrete equation,facilitating Monte Carlo Simulation(MCS)to evaluate how different scattering regimes influence received photon distribution.Three distinct Scattering Regime Contribution Weight(SRCW)probability sets were employed,each representing different UCL operational configurations dominated by specific scattering regimes.The proposed modeling approach enables a comprehensive assessment of the temporal characteristics of received optical pulses,channel loss,and time spread-ultimately defining the optimal UCL design parameters.The key findings of this study include:(1)Enhancing the FSC regime dominance leads to a quasi-light waveguide effect over link spans and small Fields of View(FOV)<25°,significantly improving channel performance in Harbor seawater compared to Coastal seawater.(2)A well-designed UCL with a small FOV(<25°)can minimise channel loss and time spread,ensuring high capacity and efficient performance in both Coastal and Harbor seawaters.(3)When BSC and ISC contributions exceed FSC dominance,the received optical pulse undergoes significant temporal broadening,particularly for larger FOV angles(>25°)and extended link spans.(4)The developed novel MCS-based discrete equation provides a simple yet robust model for simulating photon propagation in both homogeneous and inhomogeneous underwater channels.These insights contribute to developing more efficient and reliable UCL designs with military standards by enhancing UWOC system performance over a longer linkspan for a given limited optical power across various underwater environments.
基金supported by the“1·3·5 Project”for Disciplines of Excellence,West China Hospital,Sichuan University,China(ZYGD18017)。
文摘Although body mass index(BMI)is widely used as a simple tool to assess obesity,it has certain limitations and inaccuracies.It is known that visceral adipose tissue is closely related to cardiometabolic risks and all-cause mortality;however,precise measurement methods for visceral fat(magnetic resonance imaging and computed tomography)cannot be widely used.Thus,simple but accurate alternatives are valuable.Studies have shown that waist circumference-to-height ratio(WHtR)might be a superior and more accurate variable in assessing central or visceral adiposity as well as predicting risks of diabetes and other cardiometabolic diseases.Furthermore,WHtR cutoff values can be consistent across different races,age,and genders,making it a universal metric worth promoting and applying.
文摘Coordinated taxiing planning for multiple aircraft on flight deck is of vital importance which can dramatically improve the dispatching efficiency.In this paper,first,the coordinated taxiing path planning problem is transformed into a centralized optimal control problem where collision-free conditions and mechanical limits are considered.Since the formulated optimal control problem is of large state space and highly nonlinear,an efficient hierarchical initialization technique based on the Dubins-curve method is proposed.Then,a model predictive controller is designed to track the obtained reference trajectory in the presence of initial state error and external disturbances.Numerical experiments demonstrate that the proposed“offline planningþonline tracking”framework can achieve efficient and robust coordinated taxiing planning and tracking even in the presence of initial state error and continuous external disturbances.
基金supported by the National Natural Science Foundation of China(72001212,61773120)Hunan Postgraduate Research Innovation Project(CX20210031)+1 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of China(2014-92)the Innovation Team of Guangdong Provincial Department of Education(2018KCXTD031)。
文摘How to make use of limited onboard resources for complex and heavy space tasks has attracted much attention.With the continuous improvement on satellite payload capacity and the increasing complexity of observation requirements,the importance of satellite autonomous task scheduling research has gradually increased.This article first gives the problem description and mathematical model for the satellite autonomous task scheduling and then follows the steps of"satellite autonomous task scheduling,centralized autonomous collaborative task scheduling architecture,distributed autonomous collaborative task scheduling architecture,solution algorithm".Finally,facing the complex and changeable environment situation,this article proposes the future direction of satellite autonomous task scheduling.
文摘在单因素试验基础上,通过Plackett-Burman试验筛选及中心组合设计试验优化超声时间、超声温度和混酸用量三个因素对超声辅助提取人发中铅的影响。由响应面法建立二次回归模型得到最佳超声条件为:超声时间16 min,超声温度56℃,混酸体积6.50 m L。方法的相对标准偏差(RSD)为3.18%。检出限为0.80μg·L^(-1),定量限为2.7μg·L^(-1)。t检验结果表明超声提取法和湿消解法之间无显著性差异,因此用超声波辅助-原子吸收光谱法测定人发中的铅方法可行,且超声提取法耗时短、试剂用量少。
文摘目的探讨5F鞘组在经外周静脉穿刺置入中心静脉导管(peripherally inserted central catheter,PICC)中临床应用的效果。方法回顾性分析并总结2012年12月至2013年2月哈尔滨医科大学附属第一医院收治的应用5F鞘组10例行PICC患者的临床资料。结果 10例患者均顺利完成PICC,有2例患者术后出现静脉炎,其余患者均未发生严重的并发症。结论静脉穿刺条件差的患者应用5F鞘组行PICC导管有利于提高置管成功率。
文摘金枪鱼渔业区域性管理组织主要有大西洋金枪鱼养护国际委员会（International Commission for the Conservation of Atlantic Tunas-ICCAT）,印度洋金枪鱼委员会（Indian Ocean Tuna Commission -IOTC）, 中西太平洋渔业委员会（Western and Central Pacific Fisheries Commission -WCPFC）,南方蓝鳍金枪鱼养护委员会（Commission for the Conservation of Southern Blue-fin Tuna- CCSBT）等5个。
