Radix-16 Booth流水线乘法器的设计

设计了一种新颖的32×32位高速流水线乘法器结构.该结构所采用的新型Radix-16 Booth算法吸取了冗余Booth编码与改进Booth编码的优点,能简单、快速地产生复杂倍数.设计完成的乘法器只产生9个部分积,有效降低了部分积压缩阵列的规模与延时.通过对5级流水线关键路径中压缩阵列和64位超前进位(CLA)加法器的优化设计,减少了乘法器的延时和面积.经现场可编程逻辑器件仿真验证表明,与采用Radix-8 Booth算法的乘法器相比,该乘法器速度提高了11%,硬件资源减少了3%.     

RSA加密中基于二次Booth编码的Montgomery乘法器

研究可用于Montgomery算法的基于二次编码的不同阶的Booth大数乘法器的性能和面积。 通过SMIC 0.13μm工艺实现的阶64, 128和256的128 bit和256 bit的Booth大数乘法器, 分别在160 MHz和125 MHz的频率下实现模乘运算。 实验结果表明, 阶64, 128和256的Booth乘法器在速度上性能一致, 但随着阶的增加, 由于预计算和产生部分积的复杂度上升, 乘法器的面积将增加。     

双字节Booth乘法器的优化设计

在分析改进Booth算法双字节(16bit)乘法器的基础上,提出一种并行的乘法器结构,并且在最后的快速进位链中运用了新的设计,提高了乘法器的速度,相对于传统的结构减少了一位全加器的数量,达到减小电路规模和芯片面积,降低乘法器功耗的目的。     

基于冗余算法和跳跃式结构的54位乘法器的研究

为了提高乘法器的综合性能,提出了一种新的冗余Booth三阶算法和跳跃式Wallace树结构,前者可以减少部分积的数目,提高部分积的产生速度,后者可以加快部分积的压缩,减少电路内部的伪翻转,从而降低功耗.基于冗余Booth三阶算法和跳跃式Wallace树结构,采用0.25μmCMOS工艺,实现了54×54位全定制乘法器,其乘法延时为4.3 ns,芯片面积为1.38 mm2,50MHz频率下的动态功耗仅为47.2 mW.模拟验证表明,与采用传统Wallace树结构和改进Booth二阶算法的乘法器相比,该乘法器的乘法延时减少了23%,功耗降低了17%,面积减少了20%.     

固定位宽乘法器的量化误差补偿方法及电路实现

为了减小乘法器量化噪声对认知无线电信道检测性能的影响并节省芯片面积,提出一种高精度的固定位宽基-4Booth(FBB-4B)乘法器结构.该乘法器的截断部分被分为保留、自适应补偿和常数补偿3部分.常数补偿部分的量化误差补偿值合并到自适应补偿部分,根据自适应补偿部分进位状态的编码产生自适应量化误差补偿值,并设计了补偿进位生成电路.相较于截断部分全部采用自适应补偿的乘法器,FBB-4B乘法器的自适应补偿部分所包含的部分积位数较少,使得自适应补偿部分的量化误差减小,从而提高了该乘法器的精度.仿真实验表明,FBB-4B乘法器的精度比其他同类乘法器的精度提高了约13%,比理想基-4Booth乘法器的面积减少了30%左右.     

Booth编码在补码乘法中的应用

在数字信号处理中,乘法器是运算单元的核心部件之一,通过Booth编码减少部分积的数量,能提高乘法运算的速度。该文分析了优化乘法器的两种思路,推导了2基Booth编码及4基Booth编码,指出在实现乘法器中优先考虑4基Booth编码的原因,阐述了在应用Booth编码时注意的问题,在实际应用中验证了该方案的有效性和稳定性。     

MIPS的流水线技术和基于流水线的乘法器设计

在Booth算法的基础上，结合微处理器中流水线的结构，提出了1种改进的Booth乘法器，以适合全定制版的设计，有效地减小版图的面积、简化了电路的设计，并降低了芯片的功耗。     

乘法器模块在FPGA中的实现

作为数字信号处理领域的基本运算单元,乘法器在其中起到了至关重要的作用。本文设计了三种基于FPGA的数字乘法器模块,包括传统乘法器,LUT乘法器和Booth算法的乘法器,利用Modelsim仿真软件分别对三种算法进行了仿真,并用QuartusⅡ软件对所编写的Verilog程序进行编译综合,这里用到的FPGA芯片是Altera公司生产的cycloneⅡ器件,最后对结果进行了说明。     

32位时延无关异步流水线乘法器设计

提出采用Heaviside函数建立可精确描述门限门行为的数学模型，该数学模型可描述门限门的置位、复位行为．针对异步单轨逻辑健壮性差的缺点，基于零协议逻辑(Null Convention Logic)设计了双轨逻辑的时延无关32位异步流水线乘法器．乘法器基于改进的Booth编码和Wallace树．该乘法器与采取同样结构的同步乘法器的仿真结果表明，前者的性能提高了近4倍．     

基于冗余符号数的定点乘法器的设计

为提高定点乘法器速度,减少乘法器面积,基于Radix-16冗余并行乘法器,将奇数倍部分积用冗余差分形式表示;将部分积的修正位与部分积进行压缩,减少了部分积数量;通过优化控制信号产生电路、Booth解码电路和二进制转换电路的结构,进一步减少了乘法器延时和面积.TSMC 180nm工艺下的Design Complier综合结果表明,改进后冗余乘法器的面积相对减少8%,延时相对减少11%.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to