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Search Results: 1 - 10 of 18362 matches for " YingQuan Peng "
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On Expanded Cyclic Codes
Yingquan Wu
Mathematics , 2008,
Abstract: The paper has a threefold purpose. The first purpose is to present an explicit description of expanded cyclic codes defined in $\GF(q^m)$. The proposed explicit construction of expanded generator matrix and expanded parity check matrix maintains the symbol-wise algebraic structure and thus keeps many important original characteristics. The second purpose of this paper is to identify a class of constant-weight cyclic codes. Specifically, we show that a well-known class of $q$-ary BCH codes excluding the all-zero codeword are constant-weight cyclic codes. Moreover, we show this class of codes achieve the Plotkin bound. The last purpose of the paper is to characterize expanded cyclic codes utilizing the proposed expanded generator matrix and parity check matrix. We characterize the properties of component codewords of a codeword and particularly identify the precise conditions under which a codeword can be represented by a subbasis. Our developments reveal an alternative while more general view on the subspace subcodes of Reed-Solomon codes. With the new insights, we present an improved lower bound on the minimum distance of an expanded cyclic code by exploiting the generalized concatenated structure. We also show that the fixed-rate binary expanded Reed-Solomon codes are asymptotically "bad", in the sense that the ratio of minimum distance over code length diminishes with code length going to infinity. It overturns the prevalent conjecture that they are "good" codes and deviates from the ensemble of generalized Reed-Solomon codes which asymptotically achieves the Gilbert-Varshamov bound.
New List Decoding Algorithms for Reed-Solomon and BCH Codes
Yingquan Wu
Mathematics , 2007,
Abstract: In this paper we devise a rational curve fitting algorithm and apply it to the list decoding of Reed-Solomon and BCH codes. The proposed list decoding algorithms exhibit the following significant properties. 1 The algorithm corrects up to $n(1-\sqrt{1-D})$ errors for a (generalized) $(n, k, d=n-k+1)$ Reed-Solomon code, which matches the Johnson bound, where $D\eqdef \frac{d}{n}$ denotes the normalized minimum distance. In comparison with the Guruswami-Sudan algorithm, which exhibits the same list correction capability, the former requires multiplicity, which dictates the algorithmic complexity, $O(n(1-\sqrt{1-D}))$, whereas the latter requires multiplicity $O(n^2(1-D))$. With the up-to-date most efficient implementation, the former has complexity $O(n^{6}(1-\sqrt{1-D})^{7/2})$, whereas the latter has complexity $O(n^{10}(1-D)^4)$. 2. With the multiplicity set to one, the derivative list correction capability precisely sits in between the conventional hard-decision decoding and the optimal list decoding. Moreover, the number of candidate codewords is upper bounded by a constant for a fixed code rate and thus, the derivative algorithm exhibits quadratic complexity $O(n^2)$. 3. By utilizing the unique properties of the Berlekamp algorithm, the algorithm corrects up to $\frac{n}{2}(1-\sqrt{1-2D})$ errors for a narrow-sense $(n, k, d)$ binary BCH code, which matches the Johnson bound for binary codes. The algorithmic complexity is $O(n^{6}(1-\sqrt{1-2D})^7)$.
Numerical model of planar heterojunction organic solar cells
ChaoZhu Ma,YingQuan Peng,RunSheng Wang,RongHua Li,HongWei Xie,Ying Wang,JiPeng Xie,Ting Yang
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4376-4
Abstract: We present a numerical study of the effects of the energy barrier between the lowest unoccupied molecular orbital of the acceptor layer and the cathode, the thicknesses of the donor layer and acceptor layer on the distributions of carrier density, the electric fields and the electric potentials of organic planar heterojunction solar cells. We obtained the quantitative dependencies of the distribution of carrier density, electric fields and the electric potentials on these quantities. The results provide a theoretical foundation for the experimental study of open-circuit organic planar heterojunction solar cells.
Nonvolatile memory devices based on organic field-effect transistors
Hong Wang,YingQuan Peng,ZhuoYu Ji,Ming Liu,LiWei Shang,XingHua Liu
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-010-4240-y
Abstract: Among the many possible device configurations for organic memory devices, organic field-effect transistor (OFET) memory is an emerging technology with the potential to realize lightweight, low-cost, flexible charge storage media. In this feature article, the recent progress in the classes of OFET-based memory, including floating gate OFET memory, polymer electret OFET memory, ferroelectric OFET memory and several other kinds of OFET memories with unique configurations, are introduced. Finally, the prospects and problems of OFETs memory are discussed.
Numerical Study of Optimization of Layer Thickness in Bilayer Organic Light-Emitting Diodes
双层有机电致发光器件有机层厚度优化的数值研究(英文)

Peng Yingquan,Zhang Lei,Zhang Xu,
彭应全
,张磊,张旭

半导体学报 , 2003,
Abstract: A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and carrier mobility of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure anode/HTL/EML/cathode are numerically investigated.It is found that,for given values of the total thickness of organic layers,reduced depth of trap,total density of trap,and carrier mobility of HTL as well as EML,there exists an optimal thickness ratio of HTL to EML,by which a maximal quantum efficiency can be achieved.Through optimization of the thickness ratio,an enhancement of current density and quantum efficiency of as much as two orders of magnitude can be obtained.The dependences of the optimal thickness ratio to the characteristic trap energy,total density of trap and carrier mobility are numerically analyzed.
Numerical Study of Distribution of Electric Field and Carrier Concentration in Luminescent Layer of Organic Light-Emitting Devices
有机电致发光器件发光层中电场与载流子浓度分布的数值研究

Peng Yingquan,Zhang Fujia,Li Hairong,Song Chang''''an,
彭应全
,张福甲,李海蓉,宋长安

半导体学报 , 2003,
Abstract: The electrical potential,field and carrier density in emission layer of single layer organic light-emitting devices are numerically studied based on the trapped charge limited conduction theory.The electric field increases rapidly near the two electrodes,while slowly and nearly lineally in the rest regions.The most charge carriers distribute near the two electrodes and only a small amount of them distribute over the rest region.The diffusion current is the dominant component near the injection electrode,whereas the drift current dominates the rest region of the emission layer.
A Kind of Multistage Interconnection Networks with Multiple Paths
Zhou Yingquan,Min Yinghua
计算机科学技术学报 , 1996,
Abstract: Mltistage Interconnection Networks(MINs)are orten used to provide interconnections in multiprocessor systems.A unique path MIN usually has lower hardware complexity and a simple control algorithm,but it lacks fault tolerance.This paper proposes a kind of multipat MINs,which are obtained by adding auxiliary links at the final stage in Quad Tree(QT) networks so that they can provide more paths between each source-destination pair,and presents their routing algorithm which is both destination tag based and adaptive.Starting with the routing tag for the minimum path between a given source-destination pair,the routing algorithm uses a set of rules to select switches and modify routing tag.In addition to trying the auxiliary link when link0 an link1 are unavilable,link1 will be tried when link0 ys unavailable.This feature distinguishing the proposed routing algorithm form that for QT networks makes better use of all the possible paths between the given source-destination pair.In the end,this paper introduces a performance index,which is called capacity,to compare different kinds of MINs .Comparison shows that the proposed MINs have better capacity than QT networks.
Preparation and Optical Properties of 8-Hydroxylquinline Cadmium Thin Film
八羟基喹啉镉薄膜制备及其光学特性

Lu Feiping,Peng Yingquan,Song Chang''an,Xing Hongwei,Li Xunshuan,Yang Qingsen,
路飞平
,彭应全,宋长安,邢宏伟,李训栓,杨青森

半导体学报 , 2007,
Abstract: 8-hydroxylquinline cadmium(Cdq2)thin films were prepared on glass substrate using vacuum coating technology at different substrate temperatures.The surface and structure were investigated using atomic force microscopy(AFM)and X-ray diffusion(XRD),respectively.The results show that Cdq2 thin film is polycrystalline in structure,and higher substrate temperature results in better morphology,larger grain size,and better structure order.The spectroscopic ellipsometry results show that the refractive index and extinction index decrease with increasing wavelength,and the value of the refractive index and extinction coefficient increase as the substrate temperature increases.
Fabrication of a Bis (8-hydroxyquinoline) Zinc Amorphous-Film Device and Switching Effect
八羟基喹啉锌非晶薄膜器件的制备和开关特性

Shi Junpeng,Wen Zhenchao,Song Chang''''an,Chen Yin,Peng Yingquan,
时军朋
,温振超,宋长安,陈殷,彭应全

半导体学报 , 2005,
Abstract: The structure and fabrication of a Bis (8-hydroxyquinoline) zinc amorphous-film device are introduced by analysis of X-ray diffraction.The state of the Znq_2 film is confirmed by using an I-V curve.The switching effect of the Znq_2 film is obtained.We explain it using a molecular arrangement.
Temperature Characteristics of Bilayer Thin-Film Devices Under Organic Interface Limited Current Conduction
有机双层薄膜器件界面限制传导温度特性研究

Yang Qingsen,Peng Yingquan,Xing Hongwei,Li Xunshuan,Yuan Jianting,Ma Chaozhu,Zhao Ming,
杨青森
,彭应全,邢宏伟,李训栓,袁建挺,马朝柱,赵明

半导体学报 , 2008,
Abstract: Temperature characteristics are important for the performance of organic thin film devices.On the basis of the hopping theory of Miller-Abrahams,an analytical model of charge transport for bilayer organic devices under the organic-organic interface limited current conduction is developed.The dependence of current,field,and carrier distribution in bilayer organic devices with the structure of "injection electrode/LayerI/LayerII/collection electrode" on temperature are numerically analyzed.We conclude that,for a given applied voltage,when temperature is raised,the voltage of LayerIwill increase,and the field will be higher.Meanwhile,the voltage of LayerIIwill decrease,the field will become weaker accordingly,and the current of the device will increase.
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