检索结果-南通市图书馆

Phase saddle point transformation-enabled mode-adaptive detection of acoustic orbital angular momentum with high efficiency and low crosstalk

引用

Science China(Physics,Mechanics & Astronomy) 2025年

作者： Kai Wu Yang Tan jingjing liu Bin Liang Jianchun Cheng Collaborative Innovation Center of Advanced Microstructures and Key Laboratory of Modern Acoustics MOE Institute of AcousticsDepartment of Physics Nanjing University

Acoustic orbital angular momentum (OAM) provides an infinite set of orthogonal bases in Hilbert space and significantly boosts the link capacity and data transmission rate. High-capacity and low-crosstalk OAM detection within compact physical space is highly desired to effectively harness this spatial dimension of sound wave, but the existing mechanisms generally either operate only for finite OAMs with predetermined mode orders or rely on complicated active devices. Here, we propose a phase saddle point (PSP) transformation mechanism for distinguishing and demultiplexing acoustic OAM modes in a passive, mode-adaptive,high-efficiency, and high-accuracy paradigm. The phase mask characterized by a PSP in the specific area is created through the single-pass log-polar transformation without prior information of incident modes, whose interaction with incident vortex beams of different OAM modes will yield the translation of the stationary phase point and thereby generate the corresponding focused line spots at distinct lateral positions. We theoretically elucidate the mode-adaptive response of PSP transformation by deriving the quantitative relationship between the OAM order and line spot offset. This mode adaptability enables our mechanism to detect OAM of arbitrary mode orders and mode numbers with the inter-mode crosstalk being effectively suppressed, beyond attainable with the existing methods. The effectiveness of our proposed mechanism is validated by demonstrating several distinct examples of single-mode OAM sorting and multi-mode synthesized vortex beam demultiplexing. We anticipate this modeadaptive methodology, designed for compact dimensions and featuring with low crosstalk and uniform efficiency, will find important applications in OAM information processing.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Meiotic and Mitotic Cell Cycle Mutants Involved in Gametophyte Development in Arabidopsis

引用

Molecular Plant 2008年第4期1卷 564-574页

作者： jingjing liu Li-Jia Qu National Laboratory of Protein Engineering and Plant Genetic Engineering College of Life Sciences Peking University Beijing 100871 RR. China

The alternation between diploid and haploid generations is fundamental in the life cycles of both animals and plants. The meiotic cell cycle is common to both animals and plants gamete formation, but in animals the products of meiosis are gametes, whereas for most plants, subsequent mitotic cell cycles are needed for their formation. Clarifying the regulatory mechanisms of mitotic cell cycle progression during gametophyte development will help understanding of sexual reproduction in plants. Many mutants defective in gametophyte development and, in particular, many meiotic and mitotic cell cycle mutants in Arabidopsis male and female gametophyte development were identified through both forward and reverse genetics approaches.

关键词： Meiotic and Mitotic Cell Cycle Mutants Arabidopsis

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 1556 year-long early summer moisture reconstruction for the Hexi Corridor, Northwestern China

引用

Science China Earth Sciences 2019年第6期62卷 953-963页

作者： Bao YANG Jianglin WANG jingjing liu Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences

We report a 1556 year-long tree-ring width chronology for the Hexi Corridor, in the arid Northwestern China,established by applying the signal-free regional curve standardization method to 416 juniper ring-width series. We found that drought in early summer(May–June) is the primary controlling factor for tree growth in this area. We then developed an early summer moisture(i.e., scPDSI) reconstruction from 455 CE to present. Our reconstruction captures multi-centennial scale moisture variations, showing two long-term dry periods during 800–950 CE and 1000–1200 CE, and two long-term wet periods during 1200–1450 CE and 1510–1620 CE. We found strong similarities between hydroclimatic changes in the Hexi Corridor and Qaidam Basin from interannual to centennial timescales; however, at multi-centennial(>300 years) timescales, hydroclimatic variations in the two regions showed significant regional differences. The Hexi Corridor witnessed a generally dry Medieval Climate Anomaly(MCA, here 800–1200 CE) and the drying 20 th century, whereas the Qaidam Basin experienced highprecipitation periods during the MCA and 20 th century. The different correlation pattern with Northern Hemisphere temperature suggest that the Qaidam Basin will receive more precipitation under global warming, whereas the Hexi Corridor will become dryer in the future.

关键词： Hexi Corridor Tree-ring index Early-summer Hydroclimate reconstruction

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

基于可达性与改进和声算法的高比例DG交直流配电网可靠性评估

引用

供用电 2025年第1期42卷 86-95页

作者：樊文婷白牧可刘敬敬张立梅河北农业大学信息科学与技术学院河北保定071000 中国电力科学研究院有限公司北京100192

高比例分布式电源(distributed generation,DG)与冲击负荷的接入及电力电子设备的广泛应用,使配电网动态、交直流共存特性更加明显,给配电网可靠性评估带来新的挑战。综合考虑负荷优先级和孤岛功率平衡,提出了基于可达性与改进和声算法... 详细信息

高比例分布式电源(distributed generation,DG)与冲击负荷的接入及电力电子设备的广泛应用,使配电网动态、交直流共存特性更加明显,给配电网可靠性评估带来新的挑战。综合考虑负荷优先级和孤岛功率平衡,提出了基于可达性与改进和声算法的配电网可靠性评估。以高比例DG交直流配电网孤岛划分特征分析为基础,基于可达性和并行随机广度优先及深度优先搜索算法生成由含单DG和多DG孤岛构成的候选解集。通过构建重要负荷恢复量最大和孤岛功率不平衡最小的多目标模型,采用改进和声算法优化求解孤岛的Pareto解集,并基于直觉模糊TOPSIS决策分析得到最优孤岛。在此基础上,考虑不确定性因素的影响,并结合高比例DG交直流配电网的特征,构建了含单DG孤岛、多DG孤岛的可靠性计算模型。以改进RBTS BUS6F4系统进行仿真,结果表明所建目标体现了重要负荷恢复量和孤岛功率不平衡量的折中,所提求解方法提高了孤岛划分效率,所提可靠性模型适用于含高比例DG的交直流配电网。

关键词：交直流配电网高比例分布式电源孤岛划分可靠性和声算法

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

Overland flow resistance and its components for slope surfaces covered with gravel and grass

引用

International Soil and Water Conservation Research 2022年第2期10卷 273-283页

作者： Lan Ma Chengzhong Pan jingjing liu Key Laboratory of State Administration of Forestry and Grassland on Soil and Water Conservation School of Soil and Water ConservationBeijing Forestry UniversityBeijing100083China Beijing Key Laboratory of Urban Hydrological Cycle and Sponge City Technology College of Water SciencesBeijing Normal UniversityBeijing100875China Soil and Water Conservation Monitoring Center of Haihe Basin of Haihe Water Resources Commission of the Ministry of Water Resources Tianjin300170China

Overland flow resistance plays an important role in predicting hillslope hydrological and erosion pro-cesses on *** surfaces covered with grass and/or gravel may increase hydraulic resistance to overland flow,but there is little information on the determination on these resistance components in a composite *** this study,the smooth and sand-bed surfaces covered with different gravel or/and grass(cover degree¼2.5%,5%,10%,15%,20%)under five slope gradients(3,6,9,12,15)were subjected to inflows to investigate the hydraulic resistance and validate the sum law of resistance *** results showed that,the overland flow mainly belonged to transition or turbulent and supercritical flow regime with 150

关键词： Overland flow Resistance Grass Gravel Sum law

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

ALGORITHM FOR ACOUSTIC PASSIVE LOCALIZATION WITH DUAL ARRAYS

引用

Chinese Journal of Mechanical Engineering 2008年第6期21卷 14-17页

作者： JIA jingjing liu Mingjie LI Xiaofeng School of Aerospace Science and Engineering Beijing Institute of Technology Beijing 100081 China

Aiming at the problem of 3D target localization by time delay estimation, this paper proposes a new acoustic passive localization method, which can provide high precision localization estimation. The first step of the two-stage algorithm is to measure the azimuth angle and pitch angle at each single array, which can obtain high precision angle estimation but low precision range estimation. And in the second step, the location of acoustic source is calculated from the angles measured above and geometry position of the two arrays. Then the accuracy of localization estimation is discussed in theory, and the influence factors and localization error are analyzed by simulation. The simulation results validate the performance of the proposed algorithm, and show the precision of localization estimation with dual arrays is superior to single array.

关键词： Acoustic passive localization Dual arrays Target tracking

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

Space Mapping of Spline Spaces over Hierarchical T-meshes

引用

Communications in Mathematics and Statistics 2023年第2期11卷 403-438页

作者： jingjing liu Fang Deng Jiansong Deng School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026AnhuiPeople’s Republic of China School of Mathematics and Statistics North China University of Water Resources and Electric PowerZhengzhou 450045HenanPeople’s Republic of China

In this paper,we construct a bijective mapping between a biquadratic spline space over the hierarchical T-mesh and the piecewise constant space over the corresponding crossing-vertex-relationship graph(CVR graph).We propose a novel structure,by which we offer an effective and easy operative method for constructing the basis functions of the biquadratic spline *** we construct is an *** basis functions of the biquadratic spline space hold the properties such as linear independence,completeness and the property of partition of unity,which are the same as the properties for the basis functions of piecewise constant space over the CVR *** demonstrate that the new basis functions are efficient,we apply the basis functions to fit some open surfaces.

关键词： Spline spaces over T-meshes Dimension CVR graph Space mapping Basis functions

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

Cancer classification based on microarray gene expression data using a principal component accumulation method

引用

Science China Chemistry 2011年第5期54卷 802-811页

作者： liu jingjing CAI WenSheng SHAO XueGuang Research Center for Analytical Sciences College of ChemistryNankai UniversityTianjin 300071China

The classification of cancer is a major research topic in bioinformatics. The nature of high dimensionality and small size associated with gene expression data,however,makes the classification quite challenging. Although principal component analysis (PCA) is of particular interest for the high-dimensional data,it may overemphasize some aspects and ignore some other important information contained in the richly complex data,because it displays only the difference in the first twoor three-dimensional PC subspaces. Based on PCA,a principal component accumulation (PCAcc) method was proposed. It employs the information contained in multiple PC subspaces and improves the class separability of cancers. The effectiveness of the present method was evaluated by four commonly used gene expression datasets,and the results show that the method performs well for cancer classification.

关键词： cancer classification principal component analysis principal component accumulation gene expression data

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

Effect of lithium content on the electrochemical properties of solid-state-synthesized spinel Li_xMn_2O_4

引用

Rare Metals 2007年第3期26卷 280-285页

作者： LI Tao QIU Weihua ZHAO Hailei liu jingjing General Research Institute for Nonferrous Metals Beijing 100088 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Lithium-substituted LixMn2O4 （x = 0.98, 1.03, 1.08） spinel samples were synthesized by solid-state reaction. X-ray diffraction （XRD） patterns show that the prepared samples have a spinel structure with a space group of Fd 3 m. The cubic lattice parameter was determined from least-squares fitting of the XRD data. Li1.03Mn2O4 shows high capacity at both low and high current densities, while Lil.08Mn2O4shows good cycling performance but relatively low capacity when cycled at both room and elevated temperatures. A variety of electrochemical methods were employed to investigate the electrochemical properties of these series of spinel LixMn2O4.

关键词： lithium manganese oxide solid-state reaction spinel electrochemical properties

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

Electrochemical properties of spinel LiMn_2O_4 and LiAl_(0.1)Mn_(1.9)O_(3.9)F_(0.1) synthesized by solid-state reaction

引用

Journal of University of Science and Technology Beijing 2008年第2期15卷 187-191页

作者： Tao Li Weihua Qiu Hailei Zhao jingjing liu General Research Institute for Nonferrous Metals Beijing 100088 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Two types of spinel cathode powders, LiMn2O4 and LiAl0.1Mn1.9O3.9F0.1, were synthesized by solid-state reaction, X-ray diffraction （XRD） patterns of the prepared samples were identified as the spinel structure with a space group of Fd 3^- m. The cubic lattice parameter was determined from least-squares fitting of the XRD data. The LiAl0.1Mn1.9O3.9F0.1 sample showed a little lower initial capacity, but better cycling performance than the LiMn2O4 sample at both room temperature and an elevated temperature. The Vanderbilt method was used to test the electrochemical conductivity of the LiMn2O4 samples. The electrochemical impedance spectroscopy （EIS） method was employed to investigate the electrochemical properties of these spinel LiMn2O4 samples.

关键词： lithium-ion batteries positive materials LiMn2O4 solid-state reaction electrochemical properties doping

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

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：