检索结果-南通市图书馆

Extracting outer function part from Hardy space function

Science China Mathematics 2017年第11期60卷 2321-2336页

作者： tAN LiHui qian tao School of Applied Mathematics Guangdong University of Technology Faculty of Science and technology University of Macao

Any analytic signal fa(e^(it)) can be written as a product of its minimum-phase signal part(the outer function part) and its all-phase signal part(the inner function part). Due to the importance of such decomposition, Kumarasan and Rao(1999), implementing the idea of the Szeg?o limit theorem(see below),proposed an algorithm to obtain approximations of the minimum-phase signal of a polynomial analytic signal fa(e^(it)) = e^(iN0t)M∑k=0a_k^(eikt),(0.1)where a_0≠ 0, a_M≠ 0. their method involves minimizing the energy E(f_a, h_1, h_2,..., h_H) =1/(2π)∫_0^(2π)|1+H∑k=1h_k^(eikt)|~2|fa(e^(it))|~2dt(0.2) with the undetermined complex numbers hk's by the least mean square error method. In the limiting procedure H →∞, one obtains approximate solutions of the minimum-phase signal. What is achieved in the present paper is two-fold. On one hand, we rigorously prove that, if fa(e^(it)) is a polynomial analytic signal as given in(0.1),then for any integer H≥M, and with |fa(e^(it))|~2 in the integrand part of(0.2) being replaced with 1/|fa(e^(it))|~2,the exact solution of the minimum-phase signal of fa(e^(it)) can be extracted out. On the other hand, we show that the Fourier system e^(ikt) used in the above process may be replaced with the takenaka-Malmquist(tM) system, r_k(e^(it)) :=((1-|α_k|~2e^(it))/(1-α_ke^(it))^(1/2)∏_(j=1)^(k-1)(e^(it)-α_j/(1-α_je^(it))^(1/2), k = 1, 2,..., r_0(e^(it)) = 1, i.e., the least mean square error method based on the tM system can also be used to extract out approximate solutions of minimum-phase signals for any functions f_a in the Hardy space. the advantage of the tM system method is that the parameters α_1,..., α_n,...determining the system can be adaptively selected in order to increase computational efficiency. In particular,adopting the n-best rational(Blaschke form) approximation selection for the n-tuple {α_1,..., α_n}, n≥N, where N is the degree of the given rational analytic signal, the minimum-phase part of a rational analytic signal can b

关键词： complex Hardy space analytic signal Nevanlinna decomposition inner and outer functions minimum-phase signal all-phase signal takenaka-Malmquist system

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

Synergistic etching and intercalation enables ultrathin ti_(3)C_(2)t_(x)and Nb_(2)Ct_(x)MXene nanosheets

引用

Rare Metals 2023年第4期42卷 1175-1185页

作者： qian-qian Xiong tahir Muhmood Cheng-Xiao Zhao Jing-San Xu Xiao-Fei yang College of Science Nanjing Forestry UniversityNanjing210037China School of Chemistry and Physics Science and Engineering FacultyQueensland University of TechnologyBrisbaneQLD4001Australia

transition metal-containing MXene has shown great potential in the promising research fields,and its performance strongly depends on the composition,structure,dimension,and surface ***,rational design and controllable synthesis of ultrathin two-dimensional(2D)MXene nanosheets with uniform surface terminations are of great ***,the use of 2D MXene,particularly in solar-powered photocatalysis and electrocatalysis,is restricted by the formation of thick,multi-layered MXene flakes with a small interlayer spacing produced from the conventional hydrofluoric acid(HF)etching *** this work,we report a few-layer MXene nanosheets by solely employing a mixture of lithium fluoride and hydrochloric acid as the etching *** etching and intercalation technique endows MXene with ultrathin 2D nanostructures;moreover,the use of fluoride salt,rather than harmful HF,offers a safer and environmentally-friendly synthetic route for scalable green production of 2D *** the obtained ti_(3)C_(2)t_(x)and Nb_(2)Ct_(x)nanosheets show a highly efficient photoelectrochemical performance superior to highly stacked MXene *** work highlights a mild,simultaneous etching and delamination strategy for the development of high quality of 2D MXene nanosheets.

关键词： MXene Electrocatalysis Hydrogen evolution reaction(HER) two-dimensional(2D)nanomaterials

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

StRUCtURAL DEtERMINAtION OF tItANIUM-OXIDE NANOPARtICLES By X-RAy ABSORPtION SPECtROSCOPy

引用

Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 53-57页

作者： Z.y. Wu J. Zhang K. Ibrahim M.I. Abbas G. Li y. tao t.D. Hu F.Q. Liu H.J. qian y.N. Xie Q.H. Zhang L. Gao Z.Z. Chen Beijing Synchrotron Radiat. Facility Inst. of High Energy Phys. Chinese Acad. of Sci. Beijing 100039 China

As a potential application of titanium-oxide nanoparticles, it is extremely important to investigate a detailed picture of the surface and interior structural properties of nanocrystalline materials, such as rutile and anatase with diameters 7.0 and 4.5nm, respectively. X-ray absorption spectroscopy has been used to identify the local ti environment and related electronic structure. We combine the experimental results at the ti edge in both bulk and nano-crystals to determine the lattice distortion in terms of differently characteristic preedge features and the variation in the multiple-scattering region of X-ray absorption near-edge structure (XANES) spectra. the relationship between the transition peaks and the surface-to volume ratio is also discussed.

关键词： X-ray absorption near edge structure nano particle transition metal oxide

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

Improved design of special boundary elements for t-shaped reinforced concrete walls

引用

Earthquake Engineering and Engineering Vibration 2017年第1期16卷 83-95页

作者： Ji Xiaodong Liu Dan qian Jiaru Department of Civil Engineering Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry Tsinghua University Beijing 100084 China

this study examines the design provisions of the Chinese GB 50011-2010 code for seismic design of buildings for the special boundary elements of t-shaped reinforced concrete walls and proposes an improved design method. Comparison of the design provisions of the GB 50011-2010 code and those of the American code ACI 318-14 indicates a possible deficiency in the t-shaped wall design provisions in GB 50011-2010. A case study of a typical t-shaped wall designed in accordance with GB 50011-2010 also indicates the insufficient extent of the boundary element at the non-flange end and overly conservative design of the flange end boundary element. Improved designs for special boundary elements oft-shaped walls are developed using a displacement-based method. the proposed design formulas produce a longer boundary element at the non-flange end and a shorter boundary element at the flange end, relative to those of the GB 50011-2010 provisions. Extensive numerical analysis indicates that t-shaped walls designed using the proposed formulas develop inelastic drift of 0.01 for both cases of the flange in compression and in tension.

关键词： code comparison displacement-based method seismic design special boundary element t-shaped wall

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

Cloning, prokaryotic expression,purification and sequence analysis of 20S proteasome subunit gene from ***

引用

High technology Letters 2007年第2期13卷 210-215页

作者：刘燕 yang qian Department of Life Science and Engineering Harbin Institute of Technology Harbin 150001 P.R.China

the gene encoding the 20S proteasome subunit（PR29） was cloned from cDNA library of trichoderma harzianum and expressed in Escherichia coli BL21 （D3） using a pEt-28a expression system. the molecular weight of the protein was found to be approximately 29 kDa, as estimated by SDS-PAGE on gels. the target protein was insoluble when induced at 22℃ with 0.4 mmol/L IPtG, while dissoluble if induced at 37℃ with 0.8mmoL/L IPtG. the expressed product was purified through Ni-magnetic beads His Bind. the purity of the fusion protein reached above 80%. the entire eDNA sequence consisted of 1094 bp with 173 and 135 bp in 5＇ and 3＇ untranslated regions respectively. the gene encoding 261 amino acids has no signal peptide sequence. these results could provide a basis for validating the func-tions of PR29. It also provided a preliminary indication for further study of the mechanism and function of proteasome, and more information of proteasome mechanism in *** could be obtained.

关键词： proteasome prokaryotic express trichoderma harzianum

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

Wnt3a:functions and implications in cancer

引用

Chinese Journal of Cancer 2015年第12期34卷 554-562页

作者： Sha He yi Lu Xia Liu Xin Huang Evan t.Keller Chao-Nan qian Jian Zhang Key Laboratory of Longevity and Ageing-related Diseases Ministry of Education Center for translational Medicine Guangxi Medical University Department of Urology and Pathology School of MedicineUniversity of Michigan Department of Nasopharyngeal Carcinoma Sun Yat-sen University Cancer CenterState Key Laboratory of Oncology in South ChinaCollaborative Innovation Center of Cancer Medicine

Wnt3a,one of Wnt family members,plays key roles in regulating pleiotropic cellular functions,including self-renewal,proliferation,differentiation,and *** evidence has suggested that Wnt3 a promotes or suppresses tumor progression via the canonical Wnt signaling pathway depending on cancer *** addition,the roles of Wnt3 a signaling can be inhibited by multiple proteins or ***,we summarize the latest findings on Wnt3 a as an important therapeutic target in cancer.

关键词： Wnt3a,the Wnt signaling pathway, Cancer

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

Reversing the mitochondrial stress-induced exhaustion of CD8^(+)t cells for improving cancer immunotherapy

引用

Cellular & Molecular Immunology 2021年第7期18卷 1634-1637页

作者： Cheng qian Xuetao Cao National Key Laboratory of Medical Immunology Institute of ImmunologySecond Military Medical UniversityShanghaiChina Laboratory of Immunity and Inflammation College of Life SciencesNankai UniversityTianjinChina

Antigen-specific CD8+t cells that infiltrate tumor tissue have been considered the primary cytotoxic lymphocytes that exert antitumor effects,building a foundation for current immunotherapies against ***,in the face of continuous antigenic stimulation during chronic infections and cancer,t-cell differentiation leads to a state of incapacitation called t-cell exhaustion,which is a critical barrier to successful t-cell immunotherapy of *** explosive growth of malignant tumor cells accompanied by a dysfunctional vascular system and metabolite competition leads to a stressful tumor microenvironment characterized by low-oxygen tension,acidic interstitial pH,and insufficient *** evidence for the contribution of the tumor microenvironment to the metabolic reprogramming of exhausted CD8+t cells has been increasing,but the response of intratumoral t cells to metabolic stress signals is still not fully *** of a study by Scharping et al.,1 together with other recent evidence,have highlighted that the tumor microenvironment can influence the mitochondrial stress of t cells and drive the trajectory of t-cell differentiation toward *** findings add new perspectives on and insights into the molecular initiators of t-cell exhaustion and the combination of strategies that should be utilized to improve the efficacy of immunotherapy,and these perspectives are discussed in this review.

关键词： immunotherapy cancer stimulation

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

turbulence properties in the solar convection envelope:properties of the overshooting regions

引用

Chinese Journal of Astronomy and Astrophysics 2009年第5期9卷 585-595页

作者： qian-Sheng Zhang yan Li National Astronomical Observatories/yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

We apply the turbulent convection model （tCM） to investigate properties of turbulence in the solar convective envelope, especially in overshooting regions. the results show tCM gives negative turbulent heat flux uτ＇t＇ in overshooting regions, which is similar to other nonlocal turbulent convection theories. the turbulent temperature fluctuation t＇t＇ shows peaks in overshooting regions. Most important, we find that the downward overshooting region below the base of the solar convection zone is a thin cellular layer filled with roll-shaped convective cells. the overshooting length for the temperature gradient is much shorter than that for element mixing because turbulent heat flux of downward and upward moving convective cells counteract each other in this cellular overshooting region. Comparing the models＇ sound speed with observations, we find that taking the convective overshooting into account helps to improve the sound speed profile of our nonlocal solar models. Comparing the p-mode oscillation frequencies with observations, we validated that increasing the diffusion parameters and decreasing the dissipation parameters of tCM make the p-mode oscillation frequencies of the solar model be in better agreement with observations.

关键词： convection - turbulence - Sun helioseismology

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

New time Dependent Pretreat Models Based on total Variational Image Restoration

引用

Acta Mathematicae Applicatae Sinica 2011年第1期27卷 129-140页

作者： Jing Xu qian-shun Chang School of Statistics and Mathematics Zhejiang Gongshang University Hangzhou 310018 China Division of Mathematical Sciences School of Physical and Mathematical Sciences Nanyang TechnologicalUniversity 50 Nanyang Avenue Singapore 639798 Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 110190 China

In this paper, we propose new pretreat models for total variation （tV） minimization problems in image deblurring and denoising. Specially, blur operator is considered as useful information in restoration. New models in form is equivalent to pretreat the initial value by image blur operator. We successfully get a new （L. Rudin, S. Osher, and E. Fatemi） ROF model, a new level set motion model and a new anisotropic diffusion model respectively. Numerical experiments demonstrate that, under the same stopping rule, the proposed methods significantly accelerate the convergence of the toothed, save computation time and get the same restored effect.

关键词： total variation image restoration level set motion anisotropic diffusion PSNR

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

Genome-wide interrogation of transfer RNA-derived small RNAs in a mouse model of traumatic brain injury

引用

Neural Regeneration Research 2022年第2期17卷 386-394页

作者： Xiao-Jian Xu Meng-Shi yang Bin Zhang qian-qian Ge Fei Niu Jin-qian Dong yuan Zhuang Bai-yun Liu Beijing Key Laboratory of Central Nervous System Injury Beijing Neurosurgical InstituteCapital Medical UniversityBeijingChina Beijing Key Laboratory of Central Nervous System Injury and Department of Neurosurgery Beijing Neurosurgical Institute and Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Nerve Injury and Repair Center of Beijing Institute for Brain Disorders BeijingChina China National Clinical Research Center for Neurological Diseases BeijingChina

transfer RNA(t RNA)-derived small RNAs(ts RNAs) are a recently established family of regulatory small non-coding RNAs that modulate diverse biological processes. Growing evidence indicates that ts RNAs are involved in neurological disorders and play a role in the pathogenesis of neurodegenerative disease. However, whether ts RNAs are involved in traumatic brain injury-induced secondary injury remains poorly understood. In this study, a mouse controlled cortical impact model of traumatic brain injury was established, and integrated ts RNA and messenger RNA(m RNA) transcriptome sequencing were used. the results revealed that 103 ts RNAs were differentially expressed in the mouse model of traumatic brain injury at 72 hours, of which 56 ts RNAs were upregulated and 47 ts RNAs were downregulated. Based on micro RNA-like seed matching and Pearson correlation analysis, 57 differentially expressed ts RNA-m RNA interaction pairs were identified, including 29 ts RNAs and 26 m RNAs. Moreover, Gene Ontology annotation of target genes revealed that the significantly enriched terms were primarily associated with inflammation and synaptic function. Collectively, our findings suggest that ts RNAs may be associated with traumatic brain injury-induced secondary brain injury, and are thus a potential therapeutic target for traumatic brain injury. the study was approved by the Beijing Neurosurgical Institute Animal Care and Use Committee(approval No. 20190411) on April 11, 2019.

关键词： gene set enrichment analysis inflammation integrated analysis neurodegenerative disease next-generation sequencing secondary injury synaptic function transfer RNA-derived small RNAs transfer RNAs traumatic brain injury

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：