检索结果-南通市图书馆

Advances in Phytochemistry and Modern Pharmacology of Saposhnikovia Divaricata(Turcz.)Schischk

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2023年第11期29卷 1033-1044页

作者： GAO Jun-wen ZHAN Yang wang yun-he ZHAO Shu-jie HAN Zhong-ming College of Resources and Environment Jilin Agricultural UniversityChangchun(130118)China Information Center Jilin Agricultural UniversityChangchun(130118)China College of Chinese Medicinal Materials Jilin Agricultural UniversityChangchun(130118)China

Saposhnikovia divaricata(Turcz.)Schischk(***,Fangfeng)is a herb in the Apiaceae family,and its root has been used since the Western Han Dynasty(202 B.C.).Chromones and coumarins are the pharmacologically active substances in *** phytochemical and pharmacological studies have demonstrated their antipyretic,analgesic,anti-inflammatory,antioxidant,anti-tumor,and anticoagulant *** and analytical strategy theory advancements have yielded novel results;however,most investigations have been limited to the main active substances—chromones and ***,we reviewed studies related to the chemical composition and pharmacological activity of ***,analyzed the developing trends and challenges,and proposed that research should focus on components’synergistic *** also suggested that,the structure-effect relationship should be prioritized in advanced research.

关键词： coumarin synergistic priori

Simulation and Experimentation for Low Density Drain AlGaN/GaN heMT

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2014年第3期31卷 177-180页

作者： wang Chong he yun-Long DING Ning ZheNG Xue-Feng ZHANG Peng MA Xiao-Hua ZHANG Jin-Cheng HAO Yue Key Lab of Wide Band Gap Semiconductor Materials and Devices and Institute of Microelectronics Xidian University Xi'an 710071

In order to improve the breakdown voltage of AlGaN/GaN high electron mobility transistors （heMTs）, we report a feasible method of low density drain （LDD） heMT. The fluoride-based plasma treatment using CF4 gas is performed on the drain-side of the gate edge. The channel two-dimensional electron gas （2DEG） concentrations are modulated by fluoride plasma treatment, and the peak electric field at the gate edge is effectively reduced, so the breakdown voltage is improved. The electric field distributions of the LDD-heMTs are simulated using the Silvaco software, and the peak of the electric field on the gate edge is effectively reduced. Experimental results show that, compared with the conventional heMT, LDD-heMTs have a lower reverse leakage current of the gate, and the breakdown voltage is increased by 36%. The current collapse characteristics of the LDD-heMTs are confirmed by dual-pulse measurement, and an obvious pulse current reduction is due to the surface states by implanting F ions between the gate and the drain.

关键词： High electron mobility transistors

The detection, extraction and parameter estimation of extreme-mass-ratio inspirals with deep learning

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 86-96页

作者： Qianyun yun Wen-Biao Han Yi-Yang Guo he wang Minghui Du Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Shanghai Astronomical Observatory Chinese Academy of Sciences School of Physics and Astronomy Shanghai Jiao Tong University School of Astronomy and Space Science University of Chinese Academy of Sciences Taiji Laboratory for Gravitational Wave Universe (Beijing/Hangzhou) University of Chinese Academy of Sciences Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Province Key Laboratory of Quantum Theory and Applications of MoE Lanzhou University Institute of Theoretical Physics & Research Center of Gravitation Lanzhou University International Centre for Theoretical Physics Asia-Pacific (ICTP-AP) University of Chinese Academy of Sciences (UCAS) Center for Gravitational Wave Experiment National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences

One of the primary goals of space-borne gravitational wave detectors is to detect and analyze extreme-mass-ratio inspirals(EMRIs). This task is particularly challenging because EMRI signals are complex, lengthy, and faint. In this work, we introduce a2-layer convolutional neural network(CNN) approach to detect EMRI signals for space-borne detectors, achieving a true positive rate(TPR) of 96.9% at a 1% false positive rate(FPR) for signal-to-noise ratio(SNR) from 50 to 100. Especially, the key intrinsic parameters of EMRIs such as the mass, spin of the supermassive black hole(SMBH) and the initial eccentricity of the orbit can also be inferred directly by employing a neural network. The mass and spin of the SMBH can be determined at 99% and 92% respectively. This will greatly reduce the parameter spaces and computing cost for the following Bayesian parameter *** model also has a low dependency on the accuracy of the waveform model. This study underscores the potential of deep learning methods in EMRI data analysis, enabling the rapid detection of EMRI signals and efficient parameter estimation.

关键词： gravitational wave EMRIs deep-learing

On a Linear Combination Operator of Neumann-Bessel Series

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Mathematical Research and Exposition 2008年第1期28卷 156-160页

作者： wang Shu-yun he Jia-xing College of Mathematics Jilin University Jilin 130022 China

In this paper we construct a new operator Hn,r（N,B）（f; z） by means of the partial sums S（N,S）（f; z） of Neumann-Bessel series. The operator converges uniformly to any fixed continuous function f（z） on the u... 详细信息

关键词： Neumann-Bessel series kernel function best approximation order uniform conver-gence.

IoT Empowered Early Warning of Transmission Line Galloping Based on Integrated Optical Fiber Sensing and Weather Forecast Time Series Data

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2025年第1期82卷 1171-1192页

作者： Zhe Li yun Liang Jinyu wang Yang Gao State Grid henan Electric Power Company Electric Power Scientific Research Institute State Grid Henan Electric Power CompanyZhengzhou450052China

Iced transmission line galloping poses a significant threat to the safety and reliability of power systems,leading directly to line tripping,disconnections,and power *** early warning methods of iced transmission line galloping suffer from issues such as reliance on a single data source,neglect of irregular time series,and lack of attention-based closed-loop feedback,resulting in high rates of missed and false *** address these challenges,we propose an Internet of Things(IoT)empowered early warning method of transmission line galloping that integrates time series data from optical fiber sensing and weather ***,the method applies a primary adaptive weighted fusion to the IoT empowered optical fiber real-time sensing data and weather forecast data,followed by a secondary fusion based on a Back Propagation(BP)neural network,and uses the K-medoids algorithm for clustering the fused ***,an adaptive irregular time series perception adjustment module is introduced into the traditional Gated Recurrent Unit(GRU)network,and closed-loop feedback based on attentionmechanism is employed to update network parameters through gradient feedback of the loss function,enabling closed-loop training and time series data prediction of the GRU network ***,considering various types of prediction data and the duration of icing,an iced transmission line galloping risk coefficient is established,and warnings are categorized based on this ***,using an IoT-driven realistic dataset of iced transmission line galloping,the effectiveness of the proposed method is validated through multi-dimensional simulation scenarios.

关键词： Optical fiber sensing multi-source data fusion early warning of galloping time series data IoT adaptive weighted learning irregular time series perception closed-loop attention mechanism

基于F-VIKOR的质量改善部件优先级确定

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

计算机集成制造系统 2016年第12期22卷 2809-2818页

作者：周福礼王旭林云何彦东王敏重庆大学机械工程学院重庆400044 重庆大学机械传动国家重点实验室重庆400044 现代物流重庆市重点实验室重庆400044

针对汽车企业质量改善过程部件优先级确定问题,提出考虑顾客抱怨的多属性决策方法。利用基于粗糙集的属性约简技术构建评价指标体系,以梯形模糊数表征质量改善过程小组的决策信息,提出改进模糊多准则妥协解排序方法;引入信息熵获取指标... 详细信息

针对汽车企业质量改善过程部件优先级确定问题,提出考虑顾客抱怨的多属性决策方法。利用基于粗糙集的属性约简技术构建评价指标体系,以梯形模糊数表征质量改善过程小组的决策信息,提出改进模糊多准则妥协解排序方法;引入信息熵获取指标权重,通过计算综合效用值函数得出质量改善过程部件优先权排序。通过实例与文献中决策方法的对比分析可知,第一优先改善部件的决策结果高度一致,优于企业现行决策方法;当效用权重变化时最佳选择方案呈现高鲁棒性。

关键词：质量改善过程模糊多准则妥协解排序方法熵权部件优先级属性约简多属性决策

在线全文

学校读者我要写书评

暂无评论

增材-微锻造加工工艺应力场数值模拟研究

东北大学学报（自然科学版） 2022年第6期43卷 881-887页

作者：任朝晖王云贺李竺鸿王琛东北大学机械工程与自动化学院辽宁沈阳110819

激光熔丝增材制造过程中,材料快热快冷的特点使熔覆层产生不利于表面强度的残余应力,而增材-微锻加工工艺可提高增材制件的加工质量,改善增材制件微观组织及力学性能缺陷.以TC4为研究对象,通过超声微锻造工具头与熔池保持一定的相对距... 详细信息

激光熔丝增材制造过程中,材料快热快冷的特点使熔覆层产生不利于表面强度的残余应力,而增材-微锻加工工艺可提高增材制件的加工质量,改善增材制件微观组织及力学性能缺陷.以TC4为研究对象,通过超声微锻造工具头与熔池保持一定的相对距离做进给运动,对材料表面进行高频次冲击与滚压,使熔覆层表面得到改善和强化.对增材-微锻加工工艺进行顺序热结构耦合数值模拟研究,分析加工过程中熔覆层应力场变化情况.研究表明:对尚未冷却的增材熔覆层表面进行超声微锻造,熔覆层由于热源加载产生的残余拉应力转化为较为有益的残余压应力,降低了熔覆层表层缺陷发生的概率.不同的超声振幅、进给速度以及锻造温度参数对残余压应力及法向变形量有较大影响.

关键词：激光熔丝增材残余应力顺序热结构耦合超声微锻造工艺参数

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

环形ZnO薄膜谐振器的横模抑制与测试分析

物理学报 2015年第22期64卷 299-305页

作者：李玉金元秀华赵茗王运河华中科技大学光学与电子信息学院武汉430074

采用Tiersten方程研究了环形ZnO薄膜谐振器中横模寄生问题,获得了环(圆)形薄膜谐振器的横模振动方程,求得横模位移场解和频率色散方程;然后采用电磁学模式合成理论进行分析,发现环形薄膜谐振器横模频率与环形电极的内外径之比a/b有关,... 详细信息

采用Tiersten方程研究了环形ZnO薄膜谐振器中横模寄生问题,获得了环(圆)形薄膜谐振器的横模振动方程,求得横模位移场解和频率色散方程;然后采用电磁学模式合成理论进行分析,发现环形薄膜谐振器横模频率与环形电极的内外径之比a/b有关,振动模式可由圆形薄膜谐振器横模模式合成得到,通过控制a/b能够抑制横模模式数和调控基膜频率.采用外差激光干涉仪和网络矢量分析仪测量并比较了同批次的圆形和环形薄膜谐振器的上电极横模振动图样和电阻抗曲线.振动图样显示环形薄膜谐振器振动模式可由半径为a和半径为b的圆形薄膜谐振器振动模式合成,仅存在节圆数大于0的横模振动,等于0的横模模式被抑制;电阻抗曲线显示当a/b为0.436时,环形薄膜谐振器的基频(约1217 MHz)和圆形的(0,1)模式频率相等.测量数据验证了模式合成理论的分析结果正确性,为薄膜谐振器的横模抑制研究提供了理论基础和新方法.

关键词：薄膜谐振器横模模式合成 ZnO

非线性振动下卸载系统动力学及运动学特性分析

在线全文

学校读者我要写书评

暂无评论

东北大学学报（自然科学版） 2022年第12期43卷 1724-1731页

作者：周世华王云贺陈雨任朝晖东北大学机械工程与自动化学院辽宁沈阳110819

针对散体物料与振动卸载面间的摩擦、碰撞等相互作用导致的散体复杂运动行为或磨损等问题,基于库仑摩擦力模型及碰撞理论,建立具有非线性振动的卸载系统动力学模型.采用增量谐波平衡法和数值积分法,分别研究激励幅值和刚度比对系统动态... 详细信息

针对散体物料与振动卸载面间的摩擦、碰撞等相互作用导致的散体复杂运动行为或磨损等问题,基于库仑摩擦力模型及碰撞理论,建立具有非线性振动的卸载系统动力学模型.采用增量谐波平衡法和数值积分法,分别研究激励幅值和刚度比对系统动态特性、振动传递和散体物料流动规律的影响.结果表明,随着激励幅值和刚度比的增大,卸载系统的硬式非线性增强、多解区域变宽、力传递率减小并出现明显的延迟现象;由于轮胎及悬架非线性因素的影响,在相同工况下散体物料呈现出不同的流动状态,并且在跳跃、冲击后出现相对静止和相对前滑等现象.

关键词：振动助流非线性振动流动特性力传递率增量谐波平衡法