检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

一种新型多层介质悬置微带线漏波特性的分析

电波科学学报 2006年第6期21卷 816-819页

作者：周恩徐善驾中国科学技术大学电子工程与信息科学系安徽合肥230027

提出了一种多层介质悬置微带线天线结构,以改善天线的频扫特性。分析表明该结构不仅可以确保天线工作在效率较高的天线模工作区,而且它的泄漏常数在相当宽的范围内随频率都能平坦地变化。对频率扫描天线能保证当波束扫描时,可以保持一... 详细信息

提出了一种多层介质悬置微带线天线结构,以改善天线的频扫特性。分析表明该结构不仅可以确保天线工作在效率较高的天线模工作区,而且它的泄漏常数在相当宽的范围内随频率都能平坦地变化。对频率扫描天线能保证当波束扫描时,可以保持一个相对稳定不畸变的辐射方向图。

关键词：悬置微带线多层介质频率扫描天线漏波

在线全文

学校读者我要写书评

暂无评论

五轴电动转台控制系统设计

系统仿真学报 2008年第10期20卷 2557-2559,2571页

作者：徐博单家元北京理工大学北京100081

五轴转台在寻的制导武器半实物仿真系统中具有突出的优点。介绍了某型五轴电动转台控制系统的设计方案,并详细给出了转台控制系统的软件及相关硬件的设计。本套数字式集散控制系统特点在于采用自主研发的基于ARM的多功能运动控制器,能... 详细信息

五轴转台在寻的制导武器半实物仿真系统中具有突出的优点。介绍了某型五轴电动转台控制系统的设计方案,并详细给出了转台控制系统的软件及相关硬件的设计。本套数字式集散控制系统特点在于采用自主研发的基于ARM的多功能运动控制器,能够满足仿真、控制的硬实时性要求,而且在使用上具有很好的灵活性,便于实现一些复杂的控制算法。

关键词：飞行仿真寻的制导五轴转台控制系统

斜入射情况下介质周期结构三维散射问题的严格求解

在线全文

学校读者我要写书评

暂无评论

电子学报 2000年第6期28卷 72-75页

作者：杨利徐善驾中国科技大学电子工程与信息科学系合肥230027

本文采用多模网络与严格模匹配相结合的方法 ,以介质周期结构在平面波沿主平面二维斜入射情况下散射特性的分析为基础 ,经过巧妙的数学处理 ,严格求解了三维斜入射情况下介质周期结构的散射问题。

关键词：介质周期结构散射斜入射

在线全文

学校读者我要写书评

暂无评论

渐变表面左手介质表面波天线散射特性分析

电波科学学报 2008年第2期23卷 267-271页

作者：黄萌徐善驾中国科学技术大学电子工程与信息科学系安徽合肥230027

利用严格的模匹配与多模网络相结合的方法以及阶梯近似和阻抗转移技术分析了不同渐变曲线形状的左手介质表面波天线的反射与辐射特性,着重研究了不同渐变形状对天线反射与辐射特性的影响。从电磁波散射的角度将辐射问题转化为表面波和... 详细信息

利用严格的模匹配与多模网络相结合的方法以及阶梯近似和阻抗转移技术分析了不同渐变曲线形状的左手介质表面波天线的反射与辐射特性,着重研究了不同渐变形状对天线反射与辐射特性的影响。从电磁波散射的角度将辐射问题转化为表面波和空间波的传输问题,从而使分析过程得到了极大的简化。分析表明左手介质表面波天线的辐射特性与传统右手情形有很多不同,说明了产生这种不同的原因。所给出的计算结果对左手介质表面波天线的设计有实际参考意义。

关键词：左手介质表面波天线消失表面波反射和辐射

Changes in soil organic carbon pools following long-term fertilization under a rain-fed cropping system in the Loess Plateau,China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2021年第9期20卷 2512-2525页

作者： WANG Ren-jie SONG jia-shan FENG Yong-tao ZHOU jiang-xiang XIE Jun-yu Asif KHAN CHE Zong-xian ZHANG Shu-lan YANG Xue-yun Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China Ministry of Agriculture and Rural Affairs/College of Natural Resources and EnvironmentNorthwest A&F UniversityYangling 712100P.R.China Baoji Extension and Service Centre of Agricultural Technology Baoji 721001P.R.China College of Natural Resources and Environment Shanxi Agricultural UniversityTaigu 030801P.R.China Institute of Soil Fertilizer and Water-saving AgricultureGansu Academy of Agricultural SciencesLanzhou 730070P.R.China

Understanding the mechanism of soil organic carbon(SOC)sequestration is of paramount importance in sustaining crop productivity and mitigating climate ***-term trials were employed to investigate the responses of total SOC and its pools,i.e.,mineral-associated OC(MOC),particulate OC(POC,containing Light-POC and Heavy-POC),to fertilization regimes at Yangling(25-year),Tianshui(35-year)and Pingliang(37-year)under a rain-fed cropping system in the Loess *** fertilization regimes in each trial included three treatments,i.e.,control(no nutrient input,CK),chemical fertilizers(CF),and organic manure plus chemical fertilizers(MCF).Relative to the CK,long-term fertilization appreciably increased SOC storage by 134,89 and 129 kg ha^(–1)yr^(–1)under CF,and 418,153 and 384 kg ha^(–1)yr^(–1)under MCF in plough layer soils(0–20 cm),respectively,at the Yangling,Tianshui and Pingliang *** MOC pools accounted for 72,67 and 64%of the total SOC at the above three sites with sequestration rates of 76,57 and 83 kg ha^(–1)yr^(–1)under CF and 238,118 and 156 kg ha^(–1)yr^(–1)under MCF,***,the MOC pool displayed a saturation behavior under MCF *** POC accordingly constituted 27,33 and 36%of SOC,of which Light-POC accounted for 11,17 and 22%and Heavy-POC for 17,16 and 15%of SOC,*** sequestration rates of POC were 58,32 and 46 kg ha^(–1)yr^(–1)under CF,and 181,90 and 228 kg ha^(–1)yr^(–1)under MCF at the three respective sites,in which Light-POC explained 59,81 and 72%of POC under CF,and 60,40 and 69%of POC under MCF,with Heavy-POC accounting for the *** with CK,the application of CF alone did not affect the proportions of MOC or total POC to SOC,whereas MCF application markedly reduced the proportion of MOC and increased the POC ratio,mainly in the Light-POC *** distribution of SOC among different pools was closely related to the distribution and stability of *** present study confirmed that organic

关键词： chemical fertilizer organic manure mineral-associated OC particulate OC Light-POC Heavy-POC

On State Aggregation in a Class of Cyber Physical Energy Systems

在线全文

学校读者我要写书评

暂无评论

On State Aggregation in a Class of Cyber Physical Energy Sys...

Effects of changing the control ovarian stimulation protocol in patients without a transplantable embryo in the previous in vitro fertilization/intracytoplasmic sperm injection cycle

第37届中国控制会议

作者： Junjie Wu Qing-shan jia Center for Intelligent and Networked Systems Department of Automation BNRist Tsinghua University

Various cyber physical energy systems（CPES） are discrete event dynamic systems（DEDS）, in which the states are discrete and the dynamics of state transitions are triggered by events. Markov decision process（MDP） is the major mathematical framework for formulating and analyzing such systems. Look-up table algorithms are usually applied to solve optimization problems in the framework of MDP. The table stores value functions of states. When the system scale is large, it consumes huge memory space and computation budget to store and update the table. Methods like state aggregation are implemented to approximate the value functions. By aggregating several states into a "super" state, the memory space and computation budget are saved when the states are aggregated properly. In the existing researches, all the system state variables are treated equally. Actually, different state variables varies in features. In this paper, we look into the nature of different state variables in a class of cyber physical energy systems, where the state variables can be classified into two categories, action-free and actionbased. These two types of state variables are mathematically defined in this paper. We also define the concept of aggregation complexity to measure the level of aggregation of different state variables. Aggregations of these two state variables are *** experiments are conducted by a toy example of signal tracking problem and a real example of shared electric vehicles（EVs） scheduling in CPES. It is observed that aggregating the states of action-free state variables has better performance than aggregating action-based ones under the same complexity.

关键词： State aggregation Cyber physical energy systems Markov decision process Aggregation complexity Smart city

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Reproductive and Developmental Medicine 2023年第4期7卷 218-223页

作者： shan-jia Yi Yi-Hua Yang Yin Bi Zhong-Hong Zeng Xi Wang Mu-Jun Li Wen-Hong Ma Guangxi Reproductive Medical Center The First Affiliated Hospital of Guangxi Medical UniversityNanning 530021China Reproductive Medicine Center Affiliated Hospital of Guilin Medical UniversityGuilin 541001China Reproductive Medicine Center Liuzhou Maternity and Child Healthcare Hospital Liuzhou 545001China

Objective:Some patients fail to obtain an embryo for transplantation during previousin vitro fertilization(IVF)or intracytoplasmic sperm injection(ICSI)cycles,and require multiple reproductive *** study aimed to evaluate whether changing the control ovarian stimulation(COS)protocol during the subsequent stimulation cycle could improve laboratory and clinical outcomes in these ***:Patients without a transplantable embryo(TE)in the previous IVF/ICSI cycles were recruited during their second *** were classified into two groups according to their first cycle protocol:Group A,patients treated with a gonadotropinreleasing hormone agonist(GnRH-a),and Group B,patients treated with a gonadotropin-releasing hormone antagonist(GnRH-ant).The study group included patients whose stimulation protocols were changed,whereas the control group consisted of patients who used the same stimulation protocol in the second *** then compared the numbers of oocytes collected(OC)and TE,the incidence of non-TE,the pregnancy rate(PR),and the live birth rate(LBR).Results:In Group A,the numbers of OC and TE were significantly lower(6.0±4.7vs.9.4±6.4,2.3±2.2vs.4.5±3.8,P<0.05)in the study group compared with those in the control *** Group B,the numbers of OC and TE were higher(7.0±5.5vs.4.0±4.3,3.5±3.4vs.1.8±2.1,P<0.05)in the study *** was a significant increase in the incidence of non-TE(adjusted odds ratio(AOR)=2.12,95%CI:1.04–4.69)of the study group in Group A but not in Group *** significant differences in the PR or LBR were found between the study and control groups in either Group A or ***:Changing the COS protocol from GnRH-ant to GnRH-a or continuing the GnRH-a protocol can improve laboratory outcomes in patients with no TE in the previous IVF/ICSI cycle.

关键词： GnRH agonist GnRH antagonist Transplantable embryo Pregnancy rate Live birth rate

Deep learning-based lung sound analysis for intelligent stethoscope

在线全文

学校读者我要写书评

暂无评论

Military Medical Research 2024年第4期11卷 567-588页

作者： Dong-Min Huang jia Huang Kun Qiao Nan-shan Zhong Hong-Zhou Lu Wen-Jin Wang Department of Biomedical Engineering Southern University of Science and TechnologyShenzhen 518055GuangdongChina The Third People’s Hospital of Shenzhen Shenzhen 518112GuangdongChina Guangzhou Institute of Respiratory Health China State Key Laboratory of Respiratory DiseaseNational Clinical Research Center for Respiratory Diseasethe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou 510120China

Auscultation is crucial for the diagnosis of respiratory system ***,traditional stethoscopes have inherent limitations,such as inter-listener variability and subjectivity,and they cannot record respiratory sounds for offline/retrospective diagnosis or remote prescriptions in *** emergence of digital stethoscopes has overcome these limitations by allowing physicians to store and share respiratory sounds for consultation and *** this basis,machine learning,particularly deep learning,enables the fully-automatic analysis of lung sounds that may pave the way for intelligent *** review thus aims to provide a comprehensive overview of deep learning algorithms used for lung sound analysis to emphasize the significance of artificial intelligence(AI)in this *** focus on each component of deep learning-based lung sound analysis systems,including the task categories,public datasets,denoising methods,and,most importantly,existing deep learning methods,i.e.,the state-of-the-art approaches to convert lung sounds into two-dimensional(2D)spectrograms and use convolutional neural networks for the end-to-end recognition of respiratory diseases or abnormal lung ***,this review highlights current challenges in this field,including the variety of devices,noise sensitivity,and poor interpretability of deep *** address the poor reproducibility and variety of deep learning in this field,this review also provides a scalable and flexible open-source framework that aims to standardize the algorithmic workflow and provide a solid basis for replication and future extension:https://***/contactless-healthcare/Deep-Learning-for-Lung-Sound-Analysis.

关键词： Deep learning Lung sound analysis Respiratory sounds

Rice gene OsUGT75A regulates seedling emergence under deep-sowing conditions

在线全文

学校读者我要写书评

暂无评论

The Crop Journal 2024年第1期12卷 133-141页

作者： jia Zhao Siyu Liu Xiaoqian Zhao Zhibo Huang shan Sun Zixuan Zeng Yongqi He Zhoufei Wang The Laboratory of Seed Science and Technology Guangdong Key Laboratory of Plant Molecular BreedingNational Engineering Research Center of Plant Space BreedingSouth China Agricultural UniversityGuangzhou 510642GuangdongChina

Poor seedling emergence is a challenge for direct seeding of rice under deep-sowing field *** we reveal that UDP-glucosyltransferase OsUGT75A promotes rice seedling emergence under deepsowing conditions by increasing shoot *** of OsUGT75A was higher in the middle regions of the shoot and in shoots under deep-sowing *** of free abscisic acid(ABA)and jasmonates(JA)were higher in shoots of OsUGT75A mutants than in those of wild-type plants,and OsUGT75A mutants were more sensitive to ABA and JA *** shoot length was attributed to higher ABA INSENSITIVE 3(OsABI3)expression and lower JASMONATE-ZIM domain protein(OsJAZ)expression in *** extension by OsUGT75A is achieved mainly by promotion of cell *** elite haplotype of OsUGT75A associated with increased shoot length was identified among indica rice ***75A acts to increase seedling emergence under deep-sowing conditions.

关键词： Abscisic acid Deep-sowing Jasmonic acid Rice Shoot length