检索结果-南通市图书馆

Improved Capon Estimator for High-Resolution DOA Estimation and Its Statistical Analysis

IEEE/CAA Journal of Automatica Sinica 2023年第8期10卷 1716-1729页

作者： weiliang zuo Jingmin Xin Changnong Liu Nanning Zheng Akira Sano IEEE the National Key Laboratory of Human-Machine Hybrid Augmented Intelligence the National Engineering Research Center for Visual Information and Applicationsand the Institute of Artificial Intelligence and RoboticsXi’an Jiaotong UniversityXi’an 710049China the Data Center China Construction BankBeijing 100033China the Department of System Design Engineering Keio UniversityYokohama 223-8522Japan

Despite some efforts and attempts have been made to improve the direction-of-arrival(DOA)estimation performance of the standard Capon beamformer(SCB)in array processing,rigorous statistical performance analyses of these modified Capon estimators are still *** paper studies an improved Capon estimator(ICE)for estimating the DOAs of multiple uncorrelated narrowband signals,where the higherorder inverse(sample)array covariance matrix is used in the Capon-like cost *** establishing the relationship between this nonparametric estimator and the parametric and classic subspace-based MUSIC(multiple signal classification),it is clarified that as long as the power order of the inverse covariance matrix is increased to reduce the influence of signal subspace components in the ICE,the estimation performance of the ICE becomes equivalent to that of the MUSIC regardless of the signal-to-noise ratio(SNR).Furthermore the statistical performance of the ICE is analyzed,and the large-sample mean-squared-error(MSE)expression of the estimated DOA is *** the effectiveness and the theoretical analysis of the ICE are substantiated through numerical examples,where the Cramer-Rao lower bound(CRB)is used to evaluate the validity of the derived asymptotic MSE expression.

关键词： Capon beamformer direction-of-arrival(DOA)estimation large-sample mean-squared-error(MSE) subspace-based methods uniform linear array

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Inhibition of the spread of endophytic Sporisorium reilianum renders maize resistance to head smut

引用

The Crop Journal 2015年第2期3卷 87-95页

作者： Xianrong Zhao Jianrong Ye Lai Wei Nan Zhang Yuexian Xing weiliang zuo Qing Chao Guoqing Tan Mingliang Xu National Maize Improvement Center of China China Agricultural University Institute of Genetics and Developmental Biology Chinese Academy of Sciences Maize Research Institute Jilin Academy of Agricultural Sciences Institute of Botany Chinese Academy of Sciences

Head smut, caused by the fungal pathogen Sporisorium reilianum, poses a grave threat to maize(Zea mays) production worldwide. Here we report cytological and molecular evidence for maize resistance to head smut. During early stages of root infection, S. reilianum mycelium was capable of penetrating the root epidermis of both resistant(Ji1037) and susceptible(HZ4) inbred lines. S. reilianum hyphae were observed in the root–stem junction at 6 days after inoculation. In an attempt to monitor hyphal spread within the maize plant,a highly specific and sensitive real-time PCR method was established to estimate the hyphal content in infected maize tissues. During the upward growth of endophytic ***, the extent of hyphal spread was markedly different between Ji1037 and HZ4. Very little or no pathogen was detected in aerial parts of Ji1037, whereas large amounts of pathogen accumulated in aboveground tissues, particularly inflorescences, of HZ4. Thus,maize resistance to S. reilianum was achieved mainly by inhibition of endophytic hyphal growth rather than by prevention of early-root penetration by the pathogen.

关键词： Head smut Sporisorium reilianum Maize Resistance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An Atypical Thioredoxin Imparts Early Resistance to Sugarcane Mosaic Virus in Maize

引用

Molecular Plant 2017年第3期10卷 483-497页

作者： Qingqing Liu Huanhuan Liu Yangqing Gong Yongfu Tao Lu Jiang weiliang zuo Qin Yang Jianrong Ye Jinsheng Lai Jianyu Wu Thomas Lubberstedt Mingliang Xu National Maize Improvement Centre of China China Agricultural University Beijing 100193 China Department of Agronomy Iowa State University Ames IA 50011 USA College of Agronomy Synergetic Innovation Center of Henan Grain Crops and National Key Laboratory of Wheat and Maize Crop ScienceHenan Agricultural University Zhengzhou 450002 China

Sugarcane mosaic virus （SCMV） causes substantial losses of grain yield and forage biomass in susceptible maize worldwide. A major quantitative trait locus, Scmvl, has been identified to impart strong resistance to SCMV at the early infection stage. Here, we demonstrate that ZmTrxh, encoding an atypical h-type thioredoxin, is the causal gene at Scmvl, and that its transcript abundance correlated strongly with maize resistance to SCMV. ZmTrxh alleles, whether they are resistant or susceptible, share the identical coding/proximal promoter regions, but vary in the upstream regulatory regions. ZmTrxh lacks two canon- ical cysteines in the thioredoxin active-site motif and exists uniquely in the maize genome. Because of this, ZmTrxh is unable to reduce disulfide bridges but possesses a strong molecular chaperone-like activity. ZmTrxh is dispersed in maize cytoplasm to suppress SCMV viral RNA accumulation. Moreover, ZmTrxh- mediated maize resistance to SCMV showed no obvious correlation with the salicylic acid- and jasmonic acid-related defense signaling pathways. Taken together, our results indicate that ZmTrxh exhibits a distinct defense profile in maize resistance to SCMV, differing from previously characterized dominant or recessive potyvirus resistance genes.

关键词： maize sugarcane mosaic virus quantitative resistance gene h-type thioredoxin

来源：

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

A wall-associated kinase ZmWAK confers quantitative resistance to head smut in maize

A wall-associated kinase ZmWAK confers quantitative resistan...

引用

第一届全国玉米生物学学术研讨会

作者： weiliang zuo Qing Chao Nan Zhang Xianrong Zhao Yuexian Xing Guoqing Tan Kevin A.Fengler Bailin Li 徐明良 National Maize Improvement Center of China China Agricultural University Maize Research Institute Jilin Academy of Agricultural Sciences DuPont Agricultural Biotechnology 中国农业大学

Head smut is a soil-borne systemic disease in maize caused by fungus Sporisorium reilianum,and poses a grave threat to global maize *** studies detected a major resistance QTL qHSRl on maize chromosome bin2.09,which c...

关键词：

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

基于边缘似然最大化的信号源参数估计

引用

现代电子技术 2023年第23期46卷 28-35页

作者：郑超左炜亮延安九德安全应急科技有限公司总经办陕西延安716099 西安交通大学人工智能学院陕西西安710049

边缘似然最大化算法在远场信号源定位的应用已有研究,但是目前仍然没有将其推广延伸至近场信号。由于近场信号源与远场信号源之间存在着延伸关系,将上述理论自远场源延伸至近场源的研究不仅具有充分的可行性,也具有很大的实用价值。该... 详细信息

边缘似然最大化算法在远场信号源定位的应用已有研究,但是目前仍然没有将其推广延伸至近场信号。由于近场信号源与远场信号源之间存在着延伸关系,将上述理论自远场源延伸至近场源的研究不仅具有充分的可行性,也具有很大的实用价值。该方法将在边缘似然最大化理论远场源情况参数估计的基础上,避开传统估计方法的缺点,一方面设计并实现合理的算法流程,对算法的性能进行统计分析,另一方面对其做更进一步的延伸和研究探索,设计出在近场源情况下的全新参数估计算法,实现边缘似然最大化理论自远场源至近场源应用的推广。已设计的算法虽然在源数不多的情况下取得了良好的效果,但是在源个数增多的情况下性能有所下降。所提方法提高了模型的稳定性,并通过实验证明了该改进的有效性,具有理论意义与实际应用价值。希望其成果能够对声呐、移动通信和地震勘探中的目标定位和跟踪等技术的发展起到积极的促进作用。

关键词：边缘似然估计信号源定位远场源近场源参数估计目标跟踪

来源：

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Underling ZmWAK-mediated molecular mechanism of maize head smut resistance

Underling ZmWAK-mediated molecular mechanism of maize head s...

引用

第一届全国玉米生物学学术研讨会

作者：张楠 weiliang zuo Yuexian Xing Guoqing Tan Boqi Zhang Suvimon Konlasuk Qing Chao Yongsheng Chen Xianrong Zhao Jing Zhao Jianrong Ye Mingliang Xu National Maize Improvement Center of China China Agricultural University Maize Research Institute Jilin Academy of Agricultural Sciences

Head smut,caused by the fungal pathogen Sporisorium reilianum,poses a grave threat to maize(Zea mays)production ***,a transmembrane protein with an extracellular receptor domain and an intercellular kinase domain,was ...

关键词：

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

系统标定中的透视投影模型

引用

兵工自动化 2011年第3期30卷 30-35页

作者：钟韬袁威左炜亮西安交通大学自动化系西安710049

以相机的透视投影模型为基础,根据椭圆拟合与投影变换,建立使用特定靶标计算两相机相对位置的标定模型。分析在不同坐标系下物点与像点的坐标转换关系,分别通过椭圆拟合模型和精确模型,提出求解空间圆的圆心在像平面上的像坐标的算法,... 详细信息

以相机的透视投影模型为基础,根据椭圆拟合与投影变换,建立使用特定靶标计算两相机相对位置的标定模型。分析在不同坐标系下物点与像点的坐标转换关系,分别通过椭圆拟合模型和精确模型,提出求解空间圆的圆心在像平面上的像坐标的算法,并对精度和稳定性进行检验与分析。分析结果表明,椭圆拟合模型求解较简单、方便;基于透视投影变换规律的精度模型结果较精确,但需给出较多的相机外部参数。

关键词：系统标定透视投影模型椭圆拟合畸变误差

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis of C-1 and C-4 modified analogs of zanamivir as neuraminidase inhibitors

Synthesis of C-1 and C-4 modified analogs of zanamivir as ne...

引用

2011年全国药物化学学术会议——药物的源头创新

作者： Enguang Feng,Deju Ye,Ning Li,Jian Li,Jianping zuo,weiliang Zhu,Hualiang Jiang,Hong Liu~* Shanghai Institute of Materia Medica,Chinese Academy of Sciences,555 Zu chong zhi Road,Shanghai 201203,China

With the introduction of bioisosteres and scaffold hopping methods of carboxyl and guanidinium groups,57 zanamivir derivatives with C-1-modification and C-4-modification were synthesized,and their inhibitory activities against both group-1(H5N1) and group-2 neuraminidase(H3N2) were *** the series of C-1-modification,compound 9c exerts the most potency,with IC value of 0.018 and 0.18μM against N1 and N2,respectively,which is very close to that of zanamivir(H5N1:IC 0.012μM,H3N2:IC 0.015μM) and oseltamivir(H3N2:IC 0.3μM).While in the series of C-4-modification,compound D26 exerts the most potency,with IC value of 0.43 and 2.06μM against N2 and N1,*** further preliminary anti-avian influenza virus(AIV,H5N1) activities against infected MDCK cells were evaluated,and analogues D5 was shown to be～58%protective against AIV infection,which is comparable to that of zanamivir(～67%) in the same *** study of compound D5 in rats showed the compound has much longer plasma half-lives(t) than that of zanamivir after either intravenous or oral *** modeling provided the information about the binding model between these new inhibitors and neuraminidase,which is in good agreement with inhibitory *** study may represent a new starting point for future development of better anti-flu agents.

关键词：

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

Progress of a commercial ultra-stable laser system for photonic microwave generation prototype

Progress of a commercial ultra-stable laser system for photo...

引用

第十三届中国卫星导航年会

作者： zuo Yani FANG Fang Dai Shaoyang MENG Fei CAO Shiying CHEN weiliang LIU Kun WANG Xiumei LI Tianchu Time and Frequency Division National Institute of Metrology PKU-HKUST Shen Zhen-Hong Kong Institution Beijing Institute of Radio Measurement and Metrology

The frequency generated from an ultra-stable laser locked on a highfinesse FP cavity can be converted into a microwave signal with extremely high fidelity, combined with an optical frequency comb. This so-called ultra-stable microwave down-conversion system can be used as local oscillators for fountain clocks to improve their stabilities. This article introduces a compact ultra-stable laser system with some key features to improve its robustness. A commercial truncated cube FP cavity with a length of 25 mm is rigidly fixed by a four-point tetrahedron installation, which will provide effective isolation from vibration disturbances. The resonant frequency of the FP cavity is 1.5 μm, to utilize the commercial lasers with high stability and narrow linewidth. The 1.5 μm laser will be locked to the FP cavity by the PDH method. And the whole package is designed for easy transportation and resistance to vibration and temperature disturbance.

关键词： ultra-stable laser photonic microwave generation engineering prototype

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

Microwave-Vacuum Integrated Ramsey Cavity with a Low Temperature Sensitivity for Rb Fountain Clocks

Microwave-Vacuum Integrated Ramsey Cavity with a Low Tempera...

引用

第十三届中国卫星导航年会

作者： Fasong Zheng Fang Fang Xiumei Wang weiliang Chen Kun Liu Shaoyang Dai Shiying Cao Yani zuo Tianchu Li Time and Frequency Division National Institute of Metrology National Institute of Metrology PKU-HKUST Shen Zhen-Hong Kong Institution Beijing Institute of Radio Measurement and Metrology

The microwave-vacuum integrated Ramsey cavity（MVIC） with a low temperature sensitivity used for Rb fountain clocks is proposed to solve the problems that the clocks have a small operating ambient temperature range and are sensitive to the ambient temperature *** cavity is a typical TE011 cylindrical microwave resonator（CMwR）,which is made of a titanium（Ti） tube with two oxygen-free copper（OFC）end caps. The quality factor Q of this cavity is improved by coating thin layers of copper and gold on the inner surface of the tube. The cavity resonance frequency（ReF） changes are compensated thanks to the different thermal expansion of the different parts. There are two coupling holes face to face on the Ti tube wall. Each hole is sealed with a ceramic window（CW） first and then covered by a rectangular waveguide. Two microwaves are fed into the waveguides then coupled into the CMwR through the CWs,respectively. Thus, the MVIC itself can be functioned both as the microwave resonator and a part of the vacuum chamber of the clock physical package. For the prepared MVIC for Rb fountain clocks, its Qfactor is measured to be 11500 and its ReF matches the Rb transition frequency within-49 k Hz. And the sensitivity of its ReF to the temperature variation is measured to be-16.3 k Hz/℃, 7.1 times superior to a traditional OFC cavity with the same sizes. Additionally, this cavity ReF can be tuned about 130 k Hz after performing a further bake-out for the fully assembling physical package.

关键词： Time and Frequency Metrology Rb Fountain Clocks Ramsey Cavity Low Temperature Sensitivity

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：