检索结果-南通市图书馆

Novel Method for Selection of Regularization Parameter in the Near-field Acoustic Holography

Chinese Journal of Mechanical Engineering 2011年第2期24卷 285-292页

作者： ZHANG Yongbin BI Chuanxing xu liang chen Xinzhao Institute of Sound and Vibration Research Hefei University qf Technology Hefei 230009 China

Because of the ill-posedness of the near-field acoustic holography（NAH）,the regularization method is required to stabilize the computational process of *** regularization effect is related to how to select the parameter correctly and *** the L-curve method commonly used for the selection of regularization parameters has the disadvantages of wrong selection and incorrect selection,which influences the application of *** the purpose of solving the problems existed in the L-curve method,the （？）-curve method is introduced into the field of NAH,and the performance applied to NAH directly is analyzed on the basis of equivalent source method-based ***,it is found out via investigations that the（？）-curve method in NAH also has the problem of wrong selection and is unable to choose the regularization parameter *** order to select the parameter correctly and effectively,a novel method for selecting regularization parameters is proposed based on the original（？）-curve method,which can be called improved （？）-curve *** the proposed method the regularization parameters are discretized linearly between the largest singular value and the smallest singular value,and the solution norm and the residual norm corresponding to these regularization parameters are also described in a linear coordinate instead of in a lg-lg coordinate,which are the two main differences compared with the L-curve and with the original（？）-curve *** linear coordinate and using the linearly discretized regularization parameters,the solution norm is a monotonically decreasing function of the residual norm as the increase of the regularization parameter,moreover the curve is convex *** the regularization parameters can be selected correctly and effectively based on the improved（？）-curve *** a numerical simulation is done with a simply supported plate to verify the validity of the proposed *** with two actual sources,a clamped plat

关键词： near-field acoustic holography(NAH) regularization parameter selection

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

Resolution enhancement of nearfield acoustic holography by interpolation using band-limited signal restoration method

引用

Chinese Science Bulletin 2008年第20期53卷 3142-3150页

作者： xu liang BI ChuanXing chen XinZhao chen Jian Institute of Sound and Vibration Research Hefei University of Technology Hefei 230009 China

A new method based on interpolation using band-limited signal restoration method was proposed for enhancing the resolution of the nearfield acoustic holography. According to the band-limited property of the pressure on the hologram surface, a band-limited signal restoration method named Papoulis-Gerchberg algorithm was used to realize the interpolation of acoustic pressure. Therefore acoustic pressure data on the hologram surface were increased, the sampling interval was reduced, the information on evanescent waves which was lost because of the large sampling interval was partially recovered, and the resolution of nearfield acoustic holography image was improved. The experimental result shows that the method can enhance the resolution of the nearfield acoustic holography image efficiently.

关键词：近场声学全息术频带限制信号恢复方法分辨率增强插值法

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

Mirizzi syndrome:Problems and strategies

引用

Hepatobiliary & Pancreatic Diseases International 2024年第3期23卷 234-240页

作者： Jun Wu Shuang-Yong Cai xu-liang chen Zhi-Tao chen Shao-Hua Shi Department of Hepatobiliary and Pancreatic Surgery People’s Hospital of Jiulongpo DistrictChongqing 400050China Department of Hepatobiliary and Pancreatic Surgery Shulan(Hangzhou)Hospital Affiliated to Zhejiang Shuren University Shulan International Medical CollegeHangzhou 310003China

Mirizzi syndrome is a serious complication of gallstone *** is caused by the impacted stones in the gallbladder neck or cystic *** of the features of Mirizzi syndrome is severe inflammation or dense fibrosis at the Calot’s *** our clinical practice,bile duct,branches of right hepatic artery and right portal vein clinging to gallbladder infundibulum are often observed due to gallbladder infundibulum adhered to right hepatic *** intraoperative damage of branches of right hepatic artery occurs more easily than that of bile duct,all of which are hidden pitfalls for *** resonance cholangiopancreatography(MRCP)and endoscopic retrograde cholangiopancreatography(ERCP)are the preferable tools for the diagnosis of Mirizzi *** cholecystectomy in Mirizzi syndrome is easy to damage branches of right hepatic artery and bile duct due to gallbladder infundibulum adhered to right hepatic *** cholecystectomy is an easy,safe and definitive approach to Mirizzi *** combined with the application of ERCP,a laparoscopic management of Mirizzi syndrome by well-trained surgeons is feasible and *** objective of this review was to highlight its existing problems:(1)low preoperative diagnostic rate,(2)easy to damage bile duct and branches of right hepatic artery,and(3)high concomitant gallbladder ***,the review aimed to discuss the possible therapeutic strategies:(1)to enhance its preoperative recognition by imaging findings,and(2)to avoid potential pitfalls during surgery.

关键词： Mirizzi syndrome Bile duct injury Artery injury Surgical treatment Subtotal cholecystectomy

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

Approximation Algorithms for Steiner Connected Dominating Set

引用

Journal of Computer Science & Technology 2005年第5期20卷 713-716页

作者： Ya-Feng Wu Yin-Long xu Guo-liang chen National High Performance Computing Center at Hefei Department of Computer Science and Technology University of Science and Technology of China Hefei 230027 P.R. China

Steiner connected dominating set （SCDS） is a generalization of the famous connected dominating set problem, where only a specified set of required vertices has to be dominated by a connected dominating set, and known to be NP- hard. This paper firstly modifies the SCDS algorithm of Guha and Khuller and achieves a worst case approximation ratio of （2 ＋ 1/（m - 1））H（min（△, k））＋O（1）, which outperforms the previous best result （c ＋ 1）H（min（△, k））＋ O（1） in the case of m ≥ 1 ＋1/（c - 1）, where c is the best approximation ratio for Steiner tree, A is the maximum degree of the graph, k is the cardinality of the set of required vertices, m is an optional integer satisfying 0 ≤ m ≤ min（△, k） and H is the harmonic function. This paper also proposes another approximation algorithm which is based on a greedy approach. The second algorithm can establish a worst case approximation ratio of 2 ln（min（△, k））＋ O（1）, which can also be improved to 2 lnk if the optimal solution is greater than c·e^2c＋1/2（c＋1）.

关键词： approximation algorithm Steiner connected dominated set graph algorithm NP-hard

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

Systematic Identification of Rice ABC1 Gene Family and Its Response to Abiotic Stress

引用

Rice science 2011年第3期18卷 167-177页

作者： Qing-song GAO Dan ZHANG liang xu chen-wu xu Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology/Key Laboratory of Plant Functional Genomics of Ministry of Education Yangzhou University Yangzhou 225009 China

Members of the activity of bc1 complex (ABC1) family are protein kinases that are widely found in prokaryotes and eukaryotes. Previous studies showed that several plant ABC1 genes participated in the abiotic stress response. Here, we present the systematic identification of rice and Arabidopsis ABC1 genes and the expression analysis of rice ABC1 genes. A total of 15 and 17 ABC1 genes from the rice and Arabidopsis genomes, respectively, were identified using a bioinformatics approach. Phylogenetic analyses of these proteins suggested that the divergence of this family had occurred and their main characteristics were established before the monocot-dicot split. Indeed, species-specific expansion contributed to the evolution of this family in rice and Arabidopsis after the monocot-dicot split. Intron/exon structure analysis indicated that most of the orthologous genes had similar exon sizes, but diverse intron sizes, and the rice genes contained larger introns, moreover, intron gain was an important event accompanying the recent evolution of the rice ABC1 family. Multiple sequence alignment revealed one conserved amino acid segment and four conserved amino acids in the ABC1 domain. Online subcellular localization predicted that nine rice ABC1 proteins were localized in chloroplasts. Real-time RT-PCR established that the rice ABC1 genes were primarily expressed in leaves and the expression could be modulated by a broad range of abiotic factors such as H2O2, abscisic acid, low temperature, drought, darkness and high salinity. These results reveal that the rice ABC1 gene family plays roles in the environmental stress response and specific biological processes of rice.

关键词： rice activity of bc1 complex gene evolutionary analysis abiotic stress expression analysis gene function

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

Discontinuities of Banana Integrals in Dispersion Relation Representation

引用

Chinese Physics Letters 2024年第11期41卷 12-16页

作者： xu-liang chen Peng-Fei Yang and Wei chen School of Physics Sun Yat-sen UniversityGuangzhou 510275China Southern Center for Nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

We derive the discontinuities of banana integrals using the dispersion relation iteratively,and find a series of identities between the parameterized discontinuities of banana integrals(p-DOBIs).Similar to elliptic integrals,these identities enable the reduction of various p-DOBIs to be a linear combination of some fundamental *** present a practical application of p-DOBIs for deriving the Picard–Fuchs *** we establish the expression of generalized dispersion relation,which enables us to obtain the dispersion relation representation of arbitrary banana ***,we propose a hypothesis for generalized dispersion relation and p-DOBIs,which provides a simple way to calculate the discontinuities and transform dispersion relation representation to p-DOBIs.

关键词： dispersion integrals enable

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

Possible Tricritical Behavior and Anomalous Lattice Softening in van der Waals Itinerant Ferromagnet Fe3GeTe2 under High Pressure

引用

Chinese Physics Letters 2020年第7期37卷 61-64页

作者： Jie-Min xu Shu-Yang Wang Wen-Jun Wang Yong-Hui Zhou xu-liang chen Zhao-Rong Yang Zhe Qu Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field LaboratoryHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230026China

We present a high-pressure study of van der Waals ferromagnetic metal Fe3GeTe2 through electrical transport and Raman scattering measurements in diamond anvil cells at pressures up to 22.4 *** compression,the ferromagnetic transition temperature Pc manifested by a kink in resistance curve decreases monotonically and becomes undiscernable around Pc=10 GPa,indicative of suppression of the itinerant ***,by fitting the low temperature resistance to the Fermi liquid behavior of R=R0+AT2,we found that R0 shows a cusp-like anomaly and the coefficient A diverges around *** transport anomalies imply a tricritical point as commonly observed in itinerant ferromagnets under ***,the Raman-active E2g and A1g modes soften remarkably after an initial weak hardening and the peak widths of both modes broaden evidently on approaching Pc,followed by complete disappearance of both modes above this critical pressure.A possible underlying mechanism for such anomalous lattice softening near pc is discussed.

关键词： critical ferromagnetic approaching

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

Pressure-induced anomalous insulating behavior in frustrated iridate La_(3)Ir_(3)O_(11)

引用

Chinese Physics B 2021年第6期30卷 547-551页

作者： Chun-Hua chen Yong-Hui Zhou Ying Zhou Yi-Fang Yuan Chao An xu-liang chen Zhao-Ming Tian Zhao-Rong Yang Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field LaboratoryChinese Academy of SciencesHefei 230031China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230026China Institutes of Physical Science and Information Technology Anhui UniversityHefei 230601China School of Physics and Wuhan National High Magnetic Field CenterHuazhong University of Science and TechnologyWuhan 430074China High Magnetic Field Laboratory of Anhui Province Hefei 230031China

The geometrically frustrated iridate La_(3)Ir_(3)O_(11) with strong spin–orbit coupling and fractional valence was recently predicted to be a quantum spin liquid candidate at ambient conditions. Here, we systematically investigate the evolution of structural and electronic properties of La_(3)Ir_(3)O_(11) under high pressure. Electrical transport measurements reveal an abnormal insulating behavior rather than metallization above a critical pressure P_(c) ~ 38.7 GPa. Synchrotron x-ray diffraction(XRD)experiments indicate the stability of the pristine cubic KSbO_(3)-type structure up to 73.1 GPa. Nevertheless, when the pressure gradually increases across P_(c), the bulk modulus gets enhanced and the pressure dependence of bond length d_(Ir-Ir) undergoes a slope change. Consistent with the XRD data, detailed analyses of Raman spectra reveal an abnormal redshift of Raman mode and a change of Raman intensity around P_(c). Our results demonstrate that the pressure-induced insulating behavior in La_(3)Ir_(3)O_(11) can be assigned to the structural modification, such as the distortion of IrO_6 octahedra. These findings will shed light on the emergent abnormal insulating behavior in other 5 d iridates reported recently.

关键词： high pressure 5d iridates semimetal–insulator transition crystal structure

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

Pressure-induced enhancement of optoelectronic properties in PtS2

引用

Chinese Physics B 2018年第6期27卷 345-349页

作者： Yi-Fang Yuan Zhi-Tao Zhang Wei-Ke Wang Yong-Hui Zhou xu-liang chen Chao An Ran-Ran Zhang Ying Zhou Chuan-Chuan Gu liang Li Xin-Jian Li Zhao-Rong Yang Department of Physics and Laboratory of Material Physics Zhengzhou UniversityZhengzhou 450052China Anhui Provincial Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field LaboratoryChinese Academy of SciencesHefei 230031China Synergetic Innovation Center for Quantum Effects and Application Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of EducationCollege of Physics and Information ScienceHunan Normal UniversityChangsha 410081China State Key Laboratory of Material Processing and Die and Mould Technology School of Materials Science and EngineeringHuazhong University of Science and Technology(HUST)Wuhan 430074China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China

PtS2, which is one of the group-10 transition metal dichalcogenides, attracts increasing attention due to its extraordinary properties under external modulations as predicted by theory, such as tunable bandgap and indirect-to-direct gap transition under strain; however, these properties have not been verified experimentally. Here we report the first experimental exploration of its optoelectronic properties under external pressure. We find that the photocurrent is weakly pressuredependent below 3 GPa but increases significantly in the pressure range of 3 GPa–4 GPa, with a maximum ～ 6 times higher than that at ambient pressure. X-ray diffraction data shows that no structural phase transition can be observed up to26.8 GPa, which indicates a stable lattice structure of PtS2 under high pressure. This is further supported by our Raman measurements with an observation of linear blue-shifts of the two Raman-active modes to 6.4 GPa. The pressure-enhanced photocurrent is related to the indirect-to-direct/quasi-direct bandgap transition under pressure, resembling the gap behavior under compression strain as predicted theoretically.

关键词： high pressure optoelectronic properties transition metal disulfide

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

Characteristic changes in astrocyte properties during astrocyte-to-neuron conversion induced by NeuroD1/Ascl1/Dlx2

引用

Neural Regeneration Research 2025年第6期20卷 1801-1815页

作者： Qing He Zhen Wang Yuchen Wang Mengjie Zhu Zhile liang Kanghong Zhang Yuge xu Gong chen GHM Institute of CNS Regeneration Jinan UniversityGuangzhouGuangdong ProvinceChina

Direct in vivo conversion of astrocytes into functional new neurons induced by neural transcription factors has been recognized as a potential new therapeutic intervention for neural injury and degenerative disorders. However, a few recent studies have claimed that neural transcription factors cannot convert astrocytes into neurons, attributing the converted neurons to pre-existing neurons mis-expressing transgenes. In this study, we overexpressed three distinct neural transcription factors––NeuroD1, Ascl1, and Dlx2––in reactive astrocytes in mouse cortices subjected to stab injury, resulting in a series of significant changes in astrocyte properties. Initially, the three neural transcription factors were exclusively expressed in the nuclei of astrocytes. Over time, however, these astrocytes gradually adopted neuronal morphology, and the neural transcription factors was gradually observed in the nuclei of neuron-like cells instead of astrocytes. Furthermore,we noted that transcription factor-infected astrocytes showed a progressive decrease in the expression of astrocytic markers AQP4(astrocyte endfeet signal), CX43(gap junction signal), and S100β. Importantly, none of these changes could be attributed to transgene leakage into preexisting neurons. Therefore, our findings suggest that neural transcription factors such as NeuroD1, Ascl1, and Dlx2 can effectively convert reactive astrocytes into neurons in the adult mammalian brain.

关键词： aquaporin-4 Ascl1 astrocyte cortex Dlx2 gap junction glia-to-neuron conversion neural regeneration NeuroD1 reprogramming

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：