期刊文献+
共找到102篇文章
< 1 2 6 >
每页显示 20 50 100
基于分形理论的城市配网地理空间-网架布局一致性评估方法
1
作者 殷佳敏 王承民 +4 位作者 谢宁 陈志鹏 彭石 陈彬 侯昀 《智慧电力》 北大核心 2024年第4期100-107,共8页
我国国土空间规划要求电力部门展开空间布局规划。首先,将分形理论应用于描述配网网架的拓扑图,并给出相应的分形维数定义与计算方法。其次,在提出只考虑城市配网拓扑特性评估方法的基础上,综合考虑其负荷特性对分形维数指标进行加权,... 我国国土空间规划要求电力部门展开空间布局规划。首先,将分形理论应用于描述配网网架的拓扑图,并给出相应的分形维数定义与计算方法。其次,在提出只考虑城市配网拓扑特性评估方法的基础上,综合考虑其负荷特性对分形维数指标进行加权,实现从空间利用程度和中心集聚程度两个角度来评估城市配网地理空间与网架布局之间的一致性。最后,以某地区实际网架为例,将所定义的量化指标应用于评估该地区配网网架布局与地理空间之间的一致性,并对几个地区实际网架进行综合比较分析,验证了所提方法的合理性及可行性。 展开更多
关键词 城市配电网网架规划 分形理论 分形维数 用地负荷 地理空间
下载PDF
Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach
2
作者 Yi Yu Guo-Ping Liu +1 位作者 Yi Huang peng shi 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第2期405-417,共13页
DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately por... DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method. 展开更多
关键词 DC microgrids distributed control high-order fully actuated system approach linear quadratic regulator microgrid modeling secondary control
下载PDF
预测典型变形高温合金均匀化动力学的新模型
3
作者 张献光 杨文超 +9 位作者 周扬 闫建昊 肖东平 税烺 付建辉 孙飞 石鹏 陈佳俊 裴逸武 张健 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第4期1178-1190,共13页
提出一种基于扩散距离概念的变形高温合金均匀化动力学新预测模型。通过定量电子探针(EPMA)分析,系统研究典型镍基变形高温合金(GH4141)的微观偏析和均匀化动力学。研究发现,基于残余偏析指数模型预测的均匀化动力学与实际测量结果之间... 提出一种基于扩散距离概念的变形高温合金均匀化动力学新预测模型。通过定量电子探针(EPMA)分析,系统研究典型镍基变形高温合金(GH4141)的微观偏析和均匀化动力学。研究发现,基于残余偏析指数模型预测的均匀化动力学与实际测量结果之间存在一定差异。实验和理论分析均表明,考虑了过去通常被忽略的扩散方向因子的一维扩散距离模型可以合理地预测均化动力学。新模型在只需知道原始枝晶臂间距和扩散系数前提下即可完成预测计算,这为变形高温合金均匀化动力学预测提供了一种新的选择。 展开更多
关键词 变形高温合金 微观偏析 均匀化动力学 预测模型 扩散距离
下载PDF
The impact of toroidal mode coupling on high-density discharges in J-TEXT
4
作者 peng DENG Wenzhe MAO +13 位作者 Zhipeng CHEN Yinan ZHOU peng shi Zhoujun YANG Li GAO Tao LAN Jinlin XIE Hong LI Zian WEI Adi LIU Chu ZHOU Weixing DING Wandong LIU Ge ZHUANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第12期1-8,共8页
Density limit has long been a widely studied issue influencing the operating range of tokamaks.The rapid growth of the m/n=2/1(where m and n are poloidal and toroidal mode numbers,respectively)tearing mode is generall... Density limit has long been a widely studied issue influencing the operating range of tokamaks.The rapid growth of the m/n=2/1(where m and n are poloidal and toroidal mode numbers,respectively)tearing mode is generally regarded as a primary precursor to the density limit disruption.In this experiment,the coupling of the m/n=1/1 mode and the m/n=2/1 mode in highdensity plasma was observed.During a sawtooth cycle,the frequencies of the two modes gradually converge until they become equal.After that,toroidal coupling occurs between the 1/1 and 2/1 modes,resulting in a mutually fixed phase relationship.With the occurrence of toroidal coupling,the 2/1 mode is stabilized.Prior to the disruption,the cessation of the 1/1 and 2/1 mode coupling,along with the rapid growth in the amplitude of the 2/1 mode,can be observed.Additionally,under the same parameters,comparing discharges with or without the 1/1 mode,it is found that the presence of the 1/1 mode leads to higher plasma density and temperature parameters. 展开更多
关键词 toroidal coupling tearing mode density limit SAWTOOTH
下载PDF
MIDNet:Deblurring Network for Material Microstructure Images
5
作者 Jiaxiang Wang Zhengyi Li +2 位作者 peng shi Hongying Yu Dongbai Sun 《Computers, Materials & Continua》 SCIE EI 2024年第4期1187-1204,共18页
Scanning electron microscopy(SEM)is a crucial tool in the field of materials science,providing valuable insightsinto the microstructural characteristics of materials.Unfortunately,SEM images often suffer from blurrine... Scanning electron microscopy(SEM)is a crucial tool in the field of materials science,providing valuable insightsinto the microstructural characteristics of materials.Unfortunately,SEM images often suffer from blurrinesscaused by improper hardware calibration or imaging automation errors,which present challenges in analyzingand interpretingmaterial characteristics.Consequently,rectifying the blurring of these images assumes paramountsignificance to enable subsequent analysis.To address this issue,we introduce a Material Images DeblurringNetwork(MIDNet)built upon the foundation of the Nonlinear Activation Free Network(NAFNet).MIDNetis meticulously tailored to address the blurring in images capturing the microstructure of materials.The keycontributions include enhancing the NAFNet architecture for better feature extraction and representation,integratinga novel soft attention mechanism to uncover important correlations between encoder and decoder,andintroducing newmulti-loss functions to improve training effectiveness and overallmodel performance.We conducta comprehensive set of experiments utilizing the material blurry dataset and compare them to several state-of-theartdeblurring methods.The experimental results demonstrate the applicability and effectiveness of MIDNet in thedomain of deblurring material microstructure images,with a PSNR(Peak Signal-to-Noise Ratio)reaching 35.26 dBand an SSIM(Structural Similarity)of 0.946.Our dataset is available at:https://github.com/woshigui/MIDNet. 展开更多
关键词 Image deblurring material microstructure attention mechanism deep learning
下载PDF
Analysis of large datasets for identifying molecular targets in intestinal polyps and metabolic disorders
6
作者 SHAN OU YUN XU +6 位作者 QINGLAN LIU TIANWEN YANG WEI CHEN XIU YUAN XIN ZUO peng shi JIE YAO 《BIOCELL》 SCIE 2024年第3期415-429,共15页
Background:The interrelation between intestinal polyps,metabolic syndrome(MetS),and colorectal cancer(CRC)is a critical area of study.This research focuses on pinpointing potential molecular targets to understand the ... Background:The interrelation between intestinal polyps,metabolic syndrome(MetS),and colorectal cancer(CRC)is a critical area of study.This research focuses on pinpointing potential molecular targets to understand the link between intestinal polyp formation,metabolic irregularities,and CRC progression.Methods:We examined clinical samples from patients with intestinal polyps coexisting with MetS and compared them with samples from patients with standard intestinal polyps.Transcriptome sequencing and public database analysis were employed to identify significant pathways and genes.These targets were then validated through immunohistochemistry(IHC).Following the RNA interference of key target expression,a series of experiments,including the cell counting kit-8 assay,colony formation,wound healing,and Transwell assays,were conducted.Results:Comparative analysis revealed 75 up-regulated and 61 down-regulated differentially expressed genes(DEGs)in the MetS polyp group vs.the control.Kyoto encyclopedia of genes and genomes(KEGG)pathway enrichment suggested these DEGs were primarily associated with cell cycle and mitosis.Integration with comparative toxicogenomics database(CTD)and the cancer genome atlas(TCGA)databases highlighted 44 key CRC-related genes.Protein interaction networks indicated connections of purkinje cell protein 4(PCP4),olfactomedin 1(OLFM1),fibronectin 1(FN1),and transforming growth factor beta 3(TGF-β3)with the mitogen-activated protein kinase(MAPK)pathway.Tumor correlation studies suggested higher risk associations with FN1,PCP4,and TGF-β3,while OLFM1 was identified as a lower risk gene.Immunohistochemical analysis revealed a decrease in OLFM1 in MetS-associated intestinal polyps.Upon interference with OLFM1 in polyp epithelial cells,there was a significant enhancement in cell proliferation,colony formation,and cell migration and invasion capabilities.Conclusion:Our study highlights a significant decrease in OLFM1 expression in MetS-associated intestinal polyps.And,this reduction in OLFM1 is associated with enhanced cell proliferation,colony formation,and increased cell migration and invasion capabilities.These findings underscore the reduced OLFM1 expression in MetS-associated intestinal polyps may play a crucial role in promoting tumorigenic processes in colorectal pathology.Further research on OLFM1 may provide valuable insights into understanding and targeting MetS-associated intestinal polyps. 展开更多
关键词 Colorectal cancer Metabolic syndrome Intestinal polyp OLFM1 EXOSOME
下载PDF
Experimental Investigations of Quasi-Coherent Micro-Instabilities in J-TEXT Ohmic Plasmas
7
作者 石鹏 庄革 +5 位作者 程芝峰 高丽 周乙楠 刘永 罗景庭 李景春 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第5期47-52,共6页
Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient(ITG) and trapped-electron-mode instabilities usin... Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient(ITG) and trapped-electron-mode instabilities using newly developed far-forward collective scattering measurements within ohmic plasmas in the J-TEXT tokamak.The ITG mode is characterized by frequencies ranging from 30 to 100 k Hz and wavenumbers(k_(θρs)) less than 0.3. Beyond a critical plasma density threshold, the ITG mode undergoes a bifurcation, which is marked by a reduction in frequency and an enhancement in amplitude. Concurrently, enhancements in ion energy loss and degradation in confinement are observed. This ground-breaking discovery represents the first instance of direct experimental evidence that establishes a clear link between ITG instability and ion thermal transport. 展开更多
关键词 ITG mode COLLECTIVE
原文传递
Phylogenetic relationships of the zokor genus Eospalax(Mammalia,Rodentia,Spalacidae)inferred from whole-genome analyses,with description of a new species endemic to Hengduan Mountains 被引量:4
8
作者 Tao Zhang Meng-Long Lei +2 位作者 Hao Zhou Zhong-Zheng Chen peng shi 《Zoological Research》 SCIE CAS CSCD 2022年第3期331-342,共12页
Zokors in the genus Eospalax,which are endemic to northern and western China,are subterranean rodents that inhabit various niches,including grasslands,high-altitude meadows,forests,and farmlands.Six species in Eospala... Zokors in the genus Eospalax,which are endemic to northern and western China,are subterranean rodents that inhabit various niches,including grasslands,high-altitude meadows,forests,and farmlands.Six species in Eospalax were described a century ago but their taxonomy and phylogeny remain controversial.In this study,we performed high-depth whole-genome sequencing of 47 zokor samples,comprising all six previously described species.Genomic analyses revealed a reliable and robust phylogeny of Eospalax and supported the validity of the six named species.According to the inferred phylogenetic relationships,Eospalax first divergent into two clades in the early Pliocene(ca.4.68 million years ago(Ma)),one inhabiting the highaltitude Qinghai-Xizang(Tibet)Plateau(QTP)and adjacent regions,and the another inhabiting the lowaltitude Loess Plateau and Qinling-Daba Mountains.The most recent divergences occurred between E.baileyi and E.smithii and between E.rufescens and E.rothschildi in the late Pliocene(ca.2.09 and 2.19 Ma,respectively).We also collected specimens of zokors in the southern Hengduan Mountains(Muli County,Sichuan Province),far from the known distributions of all other zokors.Morphological and molecular analyses strongly suggested that the specimens represent a new species,formally described here as Eospalax muliensis sp.nov.The new species belongs to the high-altitude clade and diverged from closely related species(ca.4.22 Ma)shortly after the first divergence in Eospalax.Interestingly,Eospalax muliensis sp.nov.possesses more supposedly plesiomorphic characters,suggesting a possible origin of the genus in the Hengduan Mountains. 展开更多
关键词 ZOKOR Eospalax Phylogenomic analyses New species Hengduan Mountains
下载PDF
Experimental study of relationship between average isotopic fractionation factor and evaporation rate 被引量:1
9
作者 Tao WANG Wei-min BAO +6 位作者 Hai-li XU Zhen ZHU Si-min QU peng shi Hai-ying HU Rui-qi FAN Qian LI 《Water Science and Engineering》 EI CAS 2010年第4期394-404,共11页
Isotopic fractionation is the basis of tracing the water cycle using hydrogen and oxygen isotopes. Isotopic fractionation factors in water evaporating from free water bodies are mainly affected by temperature and rela... Isotopic fractionation is the basis of tracing the water cycle using hydrogen and oxygen isotopes. Isotopic fractionation factors in water evaporating from free water bodies are mainly affected by temperature and relative humidity, and vary significantly with these atmospheric factors over the course of a day. The evaporation rate (E) can reveal the effects of atmospheric factors. Therefore, there should be a certain functional relationship between isotopic fractionation factors and E. An average isotopic fractionation factor ( t~* ) was defined to describe isotopic differences between vapor and liquid phases in evaporation with time intervals of days. The relationship between or* and E based on the isotopic mass balance was investigated through an evaporation pan experiment with no inflow. The experimental results showed that the isotopic compositions of residual water were more enriched with time; tr* was affected by air temperature, relative humidity, and other atmospheric factors, and had a strong functional relation with E. The values of 0~* can be easily calculated with the known values of E, the initial volume of water in the pan, and isotopic compositions of residual water. 展开更多
关键词 average isotopic fractionation factor evaporation rate hydrogen and oxygen isotopes
下载PDF
C反应蛋白与高密度脂蛋白胆固醇比值、N末端脑钠肽前体与射血分数比值对STEMI患者PCI术后院内MACE的预测价值研究 被引量:3
10
作者 张兆元 马茜钰 +2 位作者 张丹 彭石 张锦 《心血管病学进展》 CAS 2023年第2期186-192,共7页
目的探讨外周血C反应蛋白与高密度脂蛋白胆固醇比值(CHR)、N末端脑钠肽前体与射血分数比值(NER)与首次ST段抬高心肌梗死(STEMI)患者冠状动脉病变严重程度的关系及对急诊经皮冠状动脉介入治疗(PCI)术后院内主要不良心血管事件(MACE)的预... 目的探讨外周血C反应蛋白与高密度脂蛋白胆固醇比值(CHR)、N末端脑钠肽前体与射血分数比值(NER)与首次ST段抬高心肌梗死(STEMI)患者冠状动脉病变严重程度的关系及对急诊经皮冠状动脉介入治疗(PCI)术后院内主要不良心血管事件(MACE)的预测价值。方法回顾性纳入2019年8月—2021年2月在兰州大学第一医院心内科因首次发生STEMI住院的610例患者,根据PCI术后院内有无发生MACE分为MACE组和非MACE组。比较两组患者临床数据及CHR、NER的差异,采用多元线性回归分析CHR和NER与冠状动脉病变Gensini评分的关系。采用logistic回归模型分析STEMI患者PCI术后住院期间发生MACE的影响因素,并绘制ROC曲线评估CHR、NER及其二者联合对院内发生MACE的预测价值。结果MACE组的CHR、NER水平均高于非MACE组,差异有统计学意义(P<0.001)。CHR、NER和冠状动脉多支病变与冠状动脉病变Gensini评分之间具有线性关系(P<0.001)。CHR(OR=1.021,95%CI 1.014~1.029)、NER(OR=1.011,95%CI 1.005~1.017)是患者院内发生MACE的独立危险因素。ROC曲线分析,CHR预测MACE的曲线下面积(AUC)为0.843(95%CI 0.812~0.871,P<0.05),截点值为23.9048,敏感性为79.26%,特异性为76.42%;NER预测MACE的AUC为0.842(95%CI 0.810~0.870,P<0.05),截点值为67.1111,敏感性为69.63%,特异性为88.42%;二者联合预测MACE的AUC为0.875(95%CI 0.846~0.900,P<0.05),截点值为0.1723,敏感性为78.52%,特异性为84.42%。结论外周血CHR和NER水平与首次STEMI患者冠状动脉病变严重程度呈线性关系,并具有辅助预测PCI术后住院期间发生MACE的价值。 展开更多
关键词 C反应蛋白与高密度脂蛋白胆固醇比值 N末端脑钠肽前体与射血分数比值 急性ST段抬高心肌梗死 主要不良心血管事件 影响因素
下载PDF
多场耦合非热平衡低温等离子体与微纳米结构材料的相互作用
11
作者 徐少锋 徐雨 +15 位作者 丁可 黄晓江 唐晓亮 杨沁玉 杨唯 彭释 王超梁 昌锡江 卢洪伟 施芸城 郭颖 杜诚然 石建军 钟方川 徐金洲 张菁 《力学学报》 EI CAS CSCD 北大核心 2023年第12期2955-2980,共26页
低温等离子体是制备微纳米材料和调控其结构特性的最重要方法之一,其中材料结构及特性的改变是等离子体电磁场、热场、化学场等多场耦合综合作用的结果.本文系统而简要地回顾了如下主要内容:电源的频率及其调制、施加方式对等离子体放... 低温等离子体是制备微纳米材料和调控其结构特性的最重要方法之一,其中材料结构及特性的改变是等离子体电磁场、热场、化学场等多场耦合综合作用的结果.本文系统而简要地回顾了如下主要内容:电源的频率及其调制、施加方式对等离子体放电特性与稳定性的影响;大气压等离子体物理化学反应动力学;等离子体场对微纳米颗粒的聚集态结构与运动的调控、以及对沉积薄膜微纳米结构的影响.总结并得出如下主要结论:放电频率、脉冲调制功率、容性或者感性耦合方式、单体种类、基片温度等对等离子体活性粒子成分与特性具有主要影响,在kHz~MHz范围可以实现稳定放电和微纳米颗粒制备和薄膜沉积;微纳米颗粒/颗粒膜结构形貌随时间和空间而发生动态变化;低温等离子体多场调制可以快速实现微纳米颗粒的结晶,并调控微纳米颗粒的成分、尺度、带隙、晶型、晶面比例及其形貌特征;引入微颗粒可以在鞘层位置悬浮形成规则的二维等离子体晶格与无序的等离子体非晶,在介观尺度研究复杂系统的结构与动理学过程. 展开更多
关键词 低温等离子体 多场耦合 微纳米颗粒 功能薄膜 结构调控
下载PDF
血清PKM2与PCT联合对脓毒症患者的诊断价值研究
12
作者 王历 彭适 +2 位作者 蔡馨 汤冬玲 张平安 《疑难病杂志》 CAS 2023年第12期1233-1237,共5页
目的探讨血清丙酮酸激酶M2(PKM2)与降钙素原(PCT)对脓毒症的诊断价值。方法选取2022年4月—2023年1月武汉大学人民医院重症监护室(ICU)收治的脓毒症患者119例(脓毒症组),同期入住重症监护室的非脓毒症患者73例(非脓毒症组)作为研究对象... 目的探讨血清丙酮酸激酶M2(PKM2)与降钙素原(PCT)对脓毒症的诊断价值。方法选取2022年4月—2023年1月武汉大学人民医院重症监护室(ICU)收治的脓毒症患者119例(脓毒症组),同期入住重症监护室的非脓毒症患者73例(非脓毒症组)作为研究对象。入院24 h内检测并比较2组患者血清PKM2和PCT水平,采用Spearman相关性检验分析脓毒症患者血清PKM2与PCT水平的相关性;采用多因素Logistic回归模型分析各指标对脓毒症发生的影响;绘制受试者工作特征(ROC)曲线评价血清PKM2、PCT及二者联合对脓毒症的诊断价值,并计算曲线下面积(AUC)。结果与非脓毒症组比较,脓毒症组血清PKM2、PCT水平明显升高(Z/P=9.373/<0.001、9.013/<0.001)。脓毒症患者血清PKM2与PCT水平呈正相关(r=0.322,P<0.001)。多因素Logistic回归分析显示,血清PKM2、PCT水平升高均是脓毒症发生的独立危险因素[OR(95%CI)=1.182(1.078~1.295)、1.582(1.186~2.110)]。ROC曲线显示,血清PKM2、PCT及二者联合诊断脓毒症的AUC分别为0.903、0.888、0.941,敏感度分别为0.863、0.918、0.932,特异度分别为0.798、0.748、0.857,二者联合诊断的效能显著高于单独检测(Z/P=2.560/0.011、3.423/<0.001)。结论脓毒症患者血清PKM2水平升高,是脓毒症发生的独立危险因素,并与PCT呈正相关,二者联合检测具有较高诊断价值。 展开更多
关键词 脓毒症 丙酮酸激酶M2 降钙素原 诊断
下载PDF
Flexible temperature sensor with high sensitivity ranging from liquid nitrogen temperature to 1200℃ 被引量:6
13
作者 Zhaojun Liu Bian Tian +6 位作者 Zhuangde Jiang Shuimin Li Jiaming Lei Zhongkai Zhang Jiangjiang Liu peng shi Qijing Lin 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2023年第1期355-366,共12页
Flexible temperature sensors have been extensively investigated due to their prospect of wide application in various flexible electronic products.However,most of the current flexible temperature sensors only work well... Flexible temperature sensors have been extensively investigated due to their prospect of wide application in various flexible electronic products.However,most of the current flexible temperature sensors only work well in a narrow temperature range,with their application at high or low temperatures still being a big challenge.This work proposes a flexible thermocouple temperature sensor based on aerogel blanket substrate,the temperature-sensitive layer of which uses the screen-printing technology to prepare indium oxide and indium tin oxide.It has good temperature sensitivity,with the test sensitivity reaching 226.7μV℃^(−1).Most importantly,it can work in a wide temperature range,from extremely low temperatures down to liquid nitrogen temperature to high temperatures up to 1200℃,which is difficult to be achieved by other existing flexible temperature sensors.This temperature sensor has huge application potential in biomedicine,aerospace and other fields. 展开更多
关键词 flexible sensor TEMPERATURE THERMOCOUPLE
下载PDF
Observation of the poloidally asymmetrical density perturbation of sawtooth collapse on J-TEXT
14
作者 周乙楠 庄革 +4 位作者 石鹏 高丽 杨州军 张晓卿 the J-TEXT Team 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第3期32-39,共8页
The detailed density perturbations provided by the advanced polarimeter-interferometer system(Polaris) during sawtooth collapse on the Joint Texas Experimental Tokamak(J-TEXT) are reported in this article.During a saw... The detailed density perturbations provided by the advanced polarimeter-interferometer system(Polaris) during sawtooth collapse on the Joint Texas Experimental Tokamak(J-TEXT) are reported in this article.During a sawtooth collapse and the crash of plasma pressure at the center,it is found that the increase in density in the region between the inversion radius and mixing radius is poloidally asymmetrical,while the increase in temperature is poloidally symmetrical.The poloidal location where the density increases is dependent on the phase of the precursory m/n=1/1 kink mode.It is always out of phase with the hot core of the m/n=1/1 mode.The behaviors of density perturbations during sawtooth collapse observed in J-TEXT are beyond the expectations of the standard model,and this can shed new light on the understanding of sawtooth collapse. 展开更多
关键词 TOKAMAK sawtooth collapse POLARIMETER density perturbation
下载PDF
舰载深弹垂直发射弹道建模及射程影响规律分析
15
作者 万小辉 彭士 +3 位作者 张海波 彭顺 戴文留 陈召任 《水下无人系统学报》 2023年第6期926-933,共8页
舰载深弹采用垂直发射后可大幅提高其平台适装性和作战效能,对提高舰船作战能力具有重要意义。文中以某垂直冷发射深弹为原型,根据垂直发射运动学及动力学方程,建立深弹垂直发射弹道计算模型,基于此模型分别考虑弹重、总冲、炮口初速、... 舰载深弹采用垂直发射后可大幅提高其平台适装性和作战效能,对提高舰船作战能力具有重要意义。文中以某垂直冷发射深弹为原型,根据垂直发射运动学及动力学方程,建立深弹垂直发射弹道计算模型,基于此模型分别考虑弹重、总冲、炮口初速、转弯高度、末端攻角、转弯结束时俯仰角、升力系数和阻力系数等影响因素,对舰载深弹射程的影响进行计算分析。结果表明:1)射程与总冲、炮口初速、转弯高度、末端攻角及升力系数具有正相关性,射程与弹重、转弯结束时俯仰角及阻力系数具有负相关性;2)弹重、总冲、炮口初速和转弯结束时俯仰角对深弹射程影响较大,末端攻角、升力系数及阻力系数对深弹射程影响相对较小,转弯高度对深弹射程几乎无影响。仿真结果可为深弹垂直发射总体及弹道设计提供参考。 展开更多
关键词 舰载深弹 垂直发射 弹道 射程
下载PDF
Reachable set estimation for discrete-time Markovian jump neural networks with unified uncertain transition probability
16
作者 Yufeng Tian Wengang Ao peng shi 《Journal of Automation and Intelligence》 2023年第3期167-174,共8页
This paper focuses on the reachable set estimation for Markovian jump neural networks with time delay.By allowing uncertainty in the transition probabilities,a framework unifies and enhances the generality and realism... This paper focuses on the reachable set estimation for Markovian jump neural networks with time delay.By allowing uncertainty in the transition probabilities,a framework unifies and enhances the generality and realism of these systems.To fully exploit the unified uncertain transition probabilities,an equivalent transformation technique is introduced as an alternative to traditional estimation methods,effectively utilizing the information of transition probabilities.Furthermore,a vector Wirtinger-based summation inequality is proposed,which captures more system information compared to existing ones.Building upon these components,a novel condition that guarantees a reachable set estimation is presented for Markovian jump neural networks with unified uncertain transition probabilities.A numerical example is illustrated to demonstrate the superiority of the approaches. 展开更多
关键词 Markovian jump neural networks Unified uncertain transition probabilities Reachable set estimation Double-boundary approach Vector wirtinger-based summation inequality
下载PDF
峨眉山茶区域公用品牌建设成效及对策建议
17
作者 高婧斐 余振怀 +3 位作者 陈含韬 梁琪惠 彭诗 邓静 《中国茶叶》 2023年第3期66-69,共4页
乐山市位于长江中上游名优绿茶产区,峨眉山茶既是国家地理标志保护产品,也是乐山茶叶区域公用品牌,更是全市农村经济发展的支柱产业。文章总结了10余年来乐山开展峨眉山茶区域品牌建设的工作举措及成效,分析了品牌配套机制不全、基础保... 乐山市位于长江中上游名优绿茶产区,峨眉山茶既是国家地理标志保护产品,也是乐山茶叶区域公用品牌,更是全市农村经济发展的支柱产业。文章总结了10余年来乐山开展峨眉山茶区域品牌建设的工作举措及成效,分析了品牌配套机制不全、基础保障不足、市场影响力不够等问题产生的原因,并分别从品牌管理、品牌营销、品牌激励方面提出了健全领导管理机制、用好品牌符号、做大品牌营销、发挥政策激励等方面的举措建议,希望为今后乐山及相似地区茶叶区域公用品牌发展提供参考。 展开更多
关键词 茶产业 区域公用品牌 品牌管理 品牌营销
下载PDF
Clinical Research Progress of Crohn
18
作者 Pingping Mei Wenzhe Feng +2 位作者 peng shi Yu Zhuang Wenxiu Zhang 《Journal of Biosciences and Medicines》 CAS 2022年第8期35-46,共12页
Crohn’s Disease (CD) is a chronic recurrent inflammatory bowel disease with unknown etiology, most common in the terminal ileum and adjacent colon. In the past 30 years, the global prevalence of CD has continued to r... Crohn’s Disease (CD) is a chronic recurrent inflammatory bowel disease with unknown etiology, most common in the terminal ileum and adjacent colon. In the past 30 years, the global prevalence of CD has continued to rise. Although the etiology is unknown, studies have shown that it is closely related to geographical environment, microfold cell damage, intestinal flora changes, epithelial barrier damage, immune dysfunction and low. The main clinical manifestations of CD are abdominal pain, chronic diarrhea, fatigue, fever and weight loss. At present, 5-aminosalicylic acid, antibiotics, glucocorticoids, immunosuppressants and biological agents are mainly used for treatment, but the drug effect is limited and the effect is not good. Recent studies have shown that Mesenchymal Stem Cells (MSC) can down-regulate immune response and promote tissue healing, which has certain safety and effectiveness in the treatment of moderate and severe CD, and has broad application prospects, but also has certain limitations. This paper summarizes the application and efficacy of related therapies in CD, providing a reference for clinicians. 展开更多
关键词 CROHN Crohn’s Drug Treatment Mesenchymal Stem Cells
下载PDF
人工智能伦理研究的知识图谱分析 被引量:9
19
作者 刘鸿宇 苗芳艳 +2 位作者 彭拾 夏思宇 王珏 《情报杂志》 CSSCI 北大核心 2019年第7期85-93,共9页
[目的/意义]随着人工智能技术的发展与应用,其衍生的伦理问题日益受到关注,但是国内从理论或技术层面防范人工智能伦理冲突的情报评述非常有限,收集人工智能伦理知识情报是当下人工智能健康发展的迫切需求。[方法/过程]借助CitespaceⅢ... [目的/意义]随着人工智能技术的发展与应用,其衍生的伦理问题日益受到关注,但是国内从理论或技术层面防范人工智能伦理冲突的情报评述非常有限,收集人工智能伦理知识情报是当下人工智能健康发展的迫切需求。[方法/过程]借助CitespaceⅢ对选自Web of Science的人工智能伦理领域文献进行知识图谱分析,分别利用检索式#1“人工智能伦理”主题文献与检索式#2“机器人伦理”主题文献进行全面且科学的知识聚类议题探析。[结果/结论]在聚类分析的基础上从人工智能载体的道德主体性研究、机器人的伦理价值敏感设计、人工道德智慧研究与人工智能技术的伦理控制四个方面对人工智能伦理研究领域进行了总结与展望。 展开更多
关键词 知识图谱 数据情报 人工智能伦理 机器人伦理
下载PDF
电气-供热管网系统等值模型与静态潮流分析方法 被引量:3
20
作者 彭石 谢宁 +1 位作者 王承民 黄淳驿 《电力系统自动化》 EI CSCD 北大核心 2022年第13期62-73,共12页
随着光伏、风电等清洁能源的持续增长,电热混合系统将是未来综合能源系统的发展趋势。首先,建立供热管网系统流体质量流量与电力系统电功率的等值关系,保证电力功率流、热力流量流可以在统一的时域尺度下进行分析。在此基础上,分别构建... 随着光伏、风电等清洁能源的持续增长,电热混合系统将是未来综合能源系统的发展趋势。首先,建立供热管网系统流体质量流量与电力系统电功率的等值关系,保证电力功率流、热力流量流可以在统一的时域尺度下进行分析。在此基础上,分别构建供热管网系统的平均温度响应模型及电锅炉外特性模型,确立供热管网系统响应状态及电、热功率流间相互影响的变量。基于牛顿法和供热管网水力计算基本原理,推导电气-供热管网系统潮流修正方程及其雅可比矩阵元素表达式,提出计及电制热效率随系统运行环境变化的电热混合系统潮流静态分析方法。最后,通过算例分析验证了所提出方法的可行性及实用性。 展开更多
关键词 综合能源系统 平均温度响应 电锅炉 电制热效率 潮流计算 静态分析
下载PDF
上一页 1 2 6 下一页 到第
使用帮助 返回顶部