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基于改进SBR的舰船SAR成像快速仿真计算方法

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电子学报 2024年第2期52卷 602-613页

作者：章琪琪张寅范君杰夏翀翔闫钧华南京航空航天大学空间光电探测与感知工业和信息化部重点实验室江苏南京211106 南京航空航天大学航天学院江苏南京211106 上海卫星工程研究所上海200240

针对SAR(Synthetic Aperture Radar)舰船成像仿真应用中电磁散射特性计算效率低下的问题,在现有SBR(Shooting and Bouncing Rays)算法的基础上,本文提出两方面改进.一是基于叶节点空间邻域编码搜索的射线管相交面元检测算法,通过只追踪... 详细信息

针对SAR(Synthetic Aperture Radar)舰船成像仿真应用中电磁散射特性计算效率低下的问题,在现有SBR(Shooting and Bouncing Rays)算法的基础上,本文提出两方面改进.一是基于叶节点空间邻域编码搜索的射线管相交面元检测算法,通过只追踪射线管中心射线并搜索叶节点空间周围潜在相交面元,在有效提升相交检测速度的同时避免遗漏相交面元;二是射线管三角剖分快速分裂算法,将射线管和相交面元投影至射线管虚拟孔径面,利用Delaunay三角剖分算法自适应地将射线管快速分裂成连续的子射线管.对典型舰船目标进行RcS(Radar cross Section)计算及SAR成像仿真实验,结果表明,在保证计算精度的前提下,本文方法计算效率比Kd树(K-dimension tree)加速SBR方法提升14倍以上,比经典自适应射线管分裂SBR方法提升3倍以上,计算效率显著提高.

关键词： SAR成像仿真 SAR回波仿真舰船RcS计算弹跳射线法自适应射线管分裂

基于藤copula理论的海上风电建模及电力市场运行分析

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电力系统自动化 2024年第11期48卷 134-142页

作者：张帅龙郑可迪刘学程兰芬唐翀陈启鑫清华大学电机工程与应用电子技术系北京市100084 新型电力系统运行与控制全国重点实验室(清华大学) 北京市100084 南方电网科学研究院有限责任公司广东省广州市510663

海上风电因具有更高的发电利用小时数,将成为中国实现“碳中和·碳达峰”的重要技术选项。随着海上风电装机容量的不断提升,其出力的间歇性、波动性将对电力系统的安全稳定和电力市场的经济运行造成显著影响。为刻画不同站点间风速的相... 详细信息

海上风电因具有更高的发电利用小时数,将成为中国实现“碳中和·碳达峰”的重要技术选项。随着海上风电装机容量的不断提升,其出力的间歇性、波动性将对电力系统的安全稳定和电力市场的经济运行造成显著影响。为刻画不同站点间风速的相关性,基于藤copula理论对海上风电的出力进行建模,并利用c藤copula函数构建多风电场出力的联合分布模型。在此基础上,提出基于共识聚类的电力市场典型阻塞场景构建方法,并采用简化的中国广东省电网架构数据开展算例仿真计算,对大规模海上风电并网前后电力系统的发电结构、碳排放量、市场电价等关键指标的变化进行实证分析。

关键词：海上风电不确定性电力现货市场节点边际电价

基于数智财务产业学院的专业课程建设研究——以大数据与会计专业群平台课程《财务会计》为例

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湖北开放职业学院学报 2024年第8期37卷 185-187页

作者：胡重毅江苏联合职业技术学院无锡旅游商贸分院江苏无锡214045

课程是人才培养的核心要素,是影响学生发展最直接的中介和变量,课程质量直接决定着人才的培养质量。五年制高职会计专业要深化教育教学改革,须自觉聚焦在课程建设上,并以此作为落实立德树人根本任务的重要落脚点。本研究通过对江苏联合... 详细信息

课程是人才培养的核心要素,是影响学生发展最直接的中介和变量,课程质量直接决定着人才的培养质量。五年制高职会计专业要深化教育教学改革,须自觉聚焦在课程建设上,并以此作为落实立德树人根本任务的重要落脚点。本研究通过对江苏联合职业技术学院无锡旅游商贸分院数智财务产业学院中的大数据与会计专业群平台课程《财务会计》进行研究,以期为新时代五年制高职的专业课程建设提供一定的参考。

关键词：产业学院课程建设专业群

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改进密闭室抽气法以准确定量旱地土壤氨挥发

农业环境科学学报 2024年第10期43卷 2434-2442页

作者：钟光迪任羡潘珊珊张翀巨晓棠海南大学热带农林学院海口570228

密闭室抽气法被认为是定量土壤NH_(3)挥发较为可靠的方法,具有灵敏度高且成本低的优点。然而,大部分研究忽略了密闭室抽气法大气进气口NH_(3)浓度,可能会高估土壤NH_(3)挥发量,目前尚缺乏相关定量研究。本研究以华北冬小麦-夏玉米轮作... 详细信息

密闭室抽气法被认为是定量土壤NH_(3)挥发较为可靠的方法,具有灵敏度高且成本低的优点。然而,大部分研究忽略了密闭室抽气法大气进气口NH_(3)浓度,可能会高估土壤NH_(3)挥发量,目前尚缺乏相关定量研究。本研究以华北冬小麦-夏玉米轮作为对象,对比分析了2019——2021年间冬小麦基肥(2次)、追肥(1次)、夏玉米四叶肥(2次)、夏玉米十叶肥(2次)共7次施肥后,改进密闭室抽气法前后测定农田土壤NH_(3)挥发的结果。改进前为包含大气背景NH_(3)的测定方法,为常规测定方法;改进后为扣除大气背景NH_(3)的测定方法,通过在田间加装3套采集距地面2.5 m高度大气的装置实现。结果表明:改进后的NH_(3)挥发通量(以N计)比改进前低0~0.23 kg·hm^(-2)·d^(-1)(0%~100%),平均值为0.06 kg·hm^(-2)·d^(-1)(33%),且37%的样本存在显著性差异(P<0.05,n=931)。改进后的NH_(3)挥发累积量比改进前低0.53~2.66 kg·hm^(2)(3%~53%),平均值为1.15 kg·hm^(-2)(29%),且47%的样本存在显著性差异(P<0.05,n=49)。改进前后NH_(3)挥发量(包括通量和累积量)存在显著差异的样本占比随着NH_(3)挥发量降低而升高。回归分析表明,改进前的NH_(3)挥发累积排放量可以用算式校正得到真实的NH_(3)累积排放量,校正式为y=0.94x-0.78(R2=0.99,P<0.01,n=49),其中y和x分别为校正后和校正前的NH_(3)挥发累积量,该算式可应用于华北土壤-作物体系NH_(3)挥发累积量的校正。综上,利用抽气法定量农田土壤NH_(3)挥发需要扣除大气背景NH_(3)以得到准确的测定结果,对于未扣除大气背景的旱地NH_(3)挥发累积量,可采用校正算式进行校正。

关键词：密闭室抽气法大气背景氨土壤氨挥发华北平原冬小麦-夏玉米轮作

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Adaptive network fuzzy inference system based navigation controller for mobile robotAdaptive network fuzzy inference system based navigation controller for mobile robot

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Frontiers of Information Technology & Electronic Engineering 2019年第2期20卷 141-151页

作者： Panati SUBBASH Kil To chong Department of Electronics and Information Engineering Chonbuk National University Advanced Electronics and Information Research center Chonbuk National University

Autonomous navigation of a mobile robot in an unknown environment with highly cluttered obstacles is a fundamental issue in mobile robotics research. We propose an adaptive network fuzzy inference system(ANFIS) based navigation controller for a differential drive mobile robot in an unknown environment with cluttered obstacles. Ultrasonic sensors are used to capture the environmental information around the mobile robot. A training data set required to train the ANFIS controller has been obtained by designing a fuzzy logic based navigation controller. Additive white Gaussian noise has been added to the sensor readings and fed to the trained ANFIS controller during mobile robot navigation, to acc.unt for the effect of environmental noise on sensor readings. The robustness of the proposed navigation controller has been evaluated by navigating the mobile robot in three different environments. The performance of the proposed controller has been verified by comparing the travelled path length/efficiency and bending energy obtained by the proposed method with reference mobile robot navigation controllers, such as neural network, fuzzy logic, and ANFIS. Simulation results presented in this paper show that the proposed controller has better performance compared with reference controllers and can successfully navigate in different environments without any collision with obstacles.

关键词： Adaptive network fuzzy inference system Additive white Gaussian noise Autonomous navigation Mobile robot

Therapeutic efficacy and stent patency of transhepatic portal vein stenting after surgery

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World Journal of Gastroenterology 2016年第44期22卷 9822-9828页

作者： ung Bae Jeon chang Won Kim Tae un Kim Ki Seok choo Joo Yeon Jang Kyung Jin Nam chong Woo chu Je Ho Ryu Department of Radiology Pusan National University Yangsan Hospital Department of Radiology Medical Research Institute Pusan National University School of Medicine and Research Institute for Convergence of Biomedical Science and Technology Pusan National University Hospital Department of Surgery Pusan National University Yangsan Hospital

AIM To evaluate portal vein(PV) stenosis and stent patency after hepatobiliary and pancreatic surgery, using abdominal computed tomography(cT).METHODS Percutaneous portal venous stenting was attempted in 22 patients with significant PV stenosis(> 50%)-after hepatobiliary or pancreatic surgery- diagnosed by abdominal cT. Stents were placed in various stenotic lesions after percutaneous transhepatic portography. Pressure gradient across the stenotic segment was measured in 14 patients. Stents were placed when the pressure gradient across the stenotic segment was > 5 mm Hg or PV stenosis was > 50%, as observed on transhepatic portography. Patients underwent followup abdominal cT and technical and clinical success, complications, and stent patency were *** Stent placement was successful in 21 patients(technical success rate: 95.5%). Stents were positioned through the main PV and superior mesenteric vein(n = 13), main PV(n = 2), right and main PV(n = 1), left and main PV(n = 4), or main PV and splenic vein(n = 1). Patients showed no complications after stent placement. The time between procedure and final follow-up cT was 41-761 d(mean: 374.5 d). Twenty stents remained patent during the entire follow-up. Stent obstruction-caused by invasion of the PV stent by a recurrent tumor- was observed in 1 patient in a follow-up cT performed after 155 d after the procedure. The cumulative stent patency rate was 95.7%. Small in-stent low-density areas were found in 11(55%) patients; however, during successive follow-up cT, the extent of these areas had *** Percutaneous transhepatic stent placement can be safe and effective in cases of PV stenosis after hepatobiliary and pancreatic surgery. Stents show excellent patency in follow-up abdominal cT, despite development of small in-stent low-density areas.

关键词： Liver Vein Stent computed tomography Surveillance Efficace

Non-existence of KAM Torus

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Acta Mathematica Sinica,English Series 2011年第2期27卷 397-404页

作者： chong Qing cHENG Department of Mathematics Nanjing University Nanjing 210093 P. R. China

Given an integrable Hamiltonian ho with n-degrees of freedom and a Diophantme trequency ω, then, arbitrarily close to h0 in the c^r topology with r 〈 2n, there exists an analytical Hamiltonian he with no KAM torus o... 详细信息

关键词： KAM theory minimal invariant measure α-function

comparative studies on Zn_(0.95)co_(0.05)O thin films on c- and R-sapphire substrates

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chinese Physics B 2009年第12期18卷 5501-5506页

作者：彭英姿 Thomas Liew Song Wen-Dong chong Tow chong Data Storage Instit u re DSI Building 5 Engineering Drive 1 Singapore 117608 Electrical and computer Engineering Department National University of Singapore Singapore 119260 School of Science Hangzhou Dianzi University Hangzhou 310018 China

Zn0.95co0.05O precipitate-free single crystal thin films were synthesized by a dual beam pulsed laser deposition method. The films form a wurtzite structure whose hexagonal axis is perpendicular or parallel to the plane of the surface depending on the c-plane （0001） or R-plane （1120） sapphire substrate. Based on the results of high-resolution transmission electron microscopy and x-ray diffraction, c-plane films show larger lattice mismatch. The films exhibit magnetic and semiconductor properties at room temperature. The coercivity of the film is about 8000 A/m at room temperature. They are soft magnetic materials with small remanent squareness S for both crystal orientations. There is no evidence to show that the anisotropy is fixed to the hexagonal axis （c-axis） for the wurtzite structure.

关键词： co-doped ZnO thin films diluted magnetic semiconductor anisotropy

大剂量左甲状腺素钠片治疗妊娠合并甲状腺功能减退症的效果

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临床医学研究与实践 2024年第4期9卷 143-146页

作者：蔡蕾崇庆国射阳县人民医院江苏盐城224300 盐城市第三人民医院江苏盐城224000

目的探讨大剂量左甲状腺素钠片治疗妊娠合并甲状腺功能减退症的效果。方法选取2016年11月至2021年11月收治的200例妊娠合并甲状腺功能减退症患者为研究对象,将其随机分为A组和B组,各100例。A组予以小剂量左甲状腺素钠片治疗,B组予以大... 详细信息

目的探讨大剂量左甲状腺素钠片治疗妊娠合并甲状腺功能减退症的效果。方法选取2016年11月至2021年11月收治的200例妊娠合并甲状腺功能减退症患者为研究对象,将其随机分为A组和B组,各100例。A组予以小剂量左甲状腺素钠片治疗,B组予以大剂量左甲状腺素钠片治疗。比较两组的治疗效果。结果治疗后,B组的甲状腺长径短于A组,甲状腺过氧化物酶抗体(TPOAb)、促甲状腺激素(TSH)水平低于A组,游离甲状腺素(FT4)水平高于A组(P0.05)。治疗后,B组的高密度脂蛋白胆固醇(HDL-c)水平高于A组,甘油三酯(TG)、总胆固醇(Tc)、低密度脂蛋白胆固醇(LDL-c)水平低于A组(P0.05)。结论大剂量左甲状腺素钠片治疗妊娠合并甲状腺功能减退症患者的效果更佳,能够明显改善甲状腺功能及血脂代谢异常,有利于改善妊娠结局,整体安全性良好。

关键词：左甲状腺素钠片大剂量妊娠合并甲状腺功能减退症血脂代谢妊娠结局甲状腺功能