The Berlekamp-Massey algorithm and linear recurring sequences over a factorial domain

We present an extended polynomial remainder sequence algorithm XPRS for R[X] whereR is a domain. From this we derive a Berlekamp-Massey algorithm BM/R overR. We show that if () is a linear recurring sequence in a factorial domainU, then the characteristic polynomials for () form aprincipal ideal which is generated by a primitive minimal polynomial. Moreover, this generator ismonic when U[[X]] is factorial (for example, whenU is Z orK[X ₁,X₂,...,X_n] whereK is a field). From XPRS we derive an algorithm MINPOL for determining the minimal polynomial of () when an upper bound on the degree of some characteristic polynomial and sufficiently many initial terms of () are known. We also show how to obtain a Berlekamp-Massey type minimal polynomial algorithm from BM/U and state BM_MINPOL/K explicitly with a further refinement. Examples are given forU=Z, GF(2)[Y].A preliminary version of this paper [7] was presented at the Third Int. Coll. on Coding Theory and Applications, Toulon, Nov. 1988.     

钢铁材料表面镀钨工艺研究

确定了Na2WO4-ZnO-WO3熔盐体系中镀钨的最佳工艺条件.以钨板为阳极、耐热钢为阴极进行了电流密度、电流波形以及温度对镀层质量的影响研究.结果表明,在空气条件下,Na2WO4:ZnO:WO3熔盐摩尔比为6:2:2时,基体不同获得良好镀层的温度不同,在钼基体上所需温度为850℃以上,在铜基体上需870℃以上,在耐热钢基体上需890℃以上;脉冲给电获得的镀层比平波直流给电的质量高.获得高质量钨镀层的最佳工艺参数为:温度范围900～950℃;采用脉冲给电,平均电流密度范围为60～80 mA/cm2.     

The mounting of samples of filamentary A15 superconductor for JC tests

We describe a technique for mounting samples of filamentary A15 superconducting materials which give reliable results in J_c tests. We discuss the possible disadvantages of the method and how these are overcome.     

A/W生物微晶玻璃材料的研究进展

生物活性玻璃陶瓷材料由于能够与活体组织自发产生紧密的化学键合而成为骨修复材料中的重要分支,其中A/W生物微晶玻璃更是由于在保持良好生物活性的基础上,力学性能接近甚至超过自然骨而作为承重的生物活性材料应用于临床.系统介绍了A/W生物微晶玻璃的制备方法、生物活性和力学性能,并展望了A/W生物微晶玻璃今后的研究发展方向.     

纳米WO3薄膜的制备及其光学性能研究

以钨酸钠为原料，采用溶胶技术结合浸渍镀膜方法制备出WO3薄膜，利用透射电子显微镜、紫外-可见分光光度计、X射线衍射仪对薄膜的性质进行了研究。实验结果表明：草酸浓度的大小对产物粒径和紫外-可见透过光谱特性均有影响，随着草酸浓度的增大，产物的粒径减小，在可见光附近的透过率增大。热处理温度对产物的光透过性有影响，处理温度越高，光透过率越大。     

30CrMnSiA和30CrMnSiNi2A钢超高温淬火组织与性能的研究

研究了３０ＣｒＭｎＳｉＡ、３０ＣｒＭｎＳｉＮｉ２Ａ钢超高温淬火组织与力学性能关系。试验结果表明，在该钢Ａｃ３以上－２００℃超高温淬火可获得组织细小均匀的板条马氏体加残余奥氏体。控制超高温淬火加热保温时间，毁唯奥氏体化又能获得细小奥氏体晶粒，从而显著提高了该钢的强韧性。     

双真空熔炼(VIM+VAR)30CrMnSiNi2A钢屈服强度的影响因素分析

对影响双真空(VIM VAR)熔炼30CrMnSiNi2A钢屈服强度(σ0-2)的因素进行了分析。结果表明，C，Si对该钢σ0-2影响较大，为了确保σ满足技术规范的要求，C，Si含量宜控制在上限；在规定200～300C回火温度范围内，较高的温度回火对提高σ0-2有利。     

5A03铝合金管轴向压缩失稳形式及影响因素分析

目的研究管材在承受轴向压缩时的力学行为、失稳形式及其影响因素。方法在航空航天用5A03铝合金管准静态轴向拉伸和压缩实验的基础上,进行了管压缩过程的有限元分析。结果5A03圆管拉伸与压缩力学性能有较大差异,具有拉、压双模量倾向,拉伸屈服强度略低于压缩屈服强度,抗拉强度略低于抗压强度,且拉伸与压缩均呈现锯齿波屈服特性;高径比影响管压缩失稳形式,小于1时管试样形成单鼓,大于1时将出现双鼓,且鼓凸在管材端面摩擦较大一端优先出现。结论管材失稳鼓凸后表现为一种具有一定规律性的非轴对称屈曲压溃。     

The furrows of Rhinolophidae revisited

Rhinolophidae, a family of echolocating bats, feature very baroque noseleaves that are assumed to shape their emission beam. Zhuang & Muller (Zhuang & Muller 2006 Phys. Rev. Lett. 97, 218701 (doi:10.1103/PhysRevLett.97.218701); Zhuang & Muller 2007 Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 76(Pt. 1), 051902 (doi:10.1103/PhysRevE.76.051902)) have proposed, based on finite element simulations, that the furrows present in the noseleaves of these bats act as resonance cavities. Using Rhinolophus rouxi as a model species, they reported that a resonance phenomenon causes the main beam to be elongated at a particular narrow frequency range. Virtually filling the furrows reduced the extent of the main lobe. However, the results of Zhuang & Muller are difficult to reconcile with the ecological background of R. rouxi. In this report, we replicate the study of Zhuang & Muller, and extend it in important ways: (i) we take the filtering of the moving pinnae into account, (ii) we use a model of the echolocation task faced by Rhinolophidae to estimate the effect of any alterations to the emission beam on the echolocation performance of the bat, and (iii) we validate our simulations using a physical mock-up of the morphology of R. rouxi. In contrast to Zhuang & Muller, we find the furrows to focus the emitted energy across the whole range of frequencies contained in the calls of R. rouxi (both in simulations and in measurements). Depending on the frequency, the focusing effect of the furrows has different consequences for the estimated echolocation performance. We argue that the furrows act to focus the beam in order to reduce the influence of clutter echoes.     

Enhancement of the efficiency and the color stabilization in green organic light-emitting devices with multiple heterostructures acting as a hole transport layer

The electrical and the optical properties of organic light-emitting devices (OLEDs), with and without multiple heterostructures consisting of N, N-bis-(1-naphthyl)-N, N-diphenyl-1,1-biphenyl-4,4-diamine (NPB)/5,6,11,12-tetraphenylnaphthacene (rubrene) acting as a hole transport layer (HTL), were investigated. The OLEDs with 3 periods of NPB/mixed rubrene:NPB multiple heterostructures acting as an HTL showed the highest luminances and efficiencies. While the electroluminescence (EL) peak corresponding to the rubrene layer did not appear for the OLEDs with 3 periods of NPB/mixed rubrene:NPB multiple heterostructures, only the EL peak related to the tris (8-hydroxyquinoline) aluminum layer was observed. The Commission Internationale de l’Eclairage chromaticity coordinates of the OLEDs with 3 periods of NPB/mixed rubrene:NPB multiple heterostructures at 14 V were (0.321, 0.531), indicative of a deep stabilized green color.     

Study of superconductors by a.c. susceptibility

An apparatus used for a.c. susceptibility measurements is described and the usefulness of a.c. susceptibility measurements for investigating superconductors is discussed. The importance of carefully studying the real and imaginary parts of a.c. susceptibility is pointed out as illustrated by the results obtained on A15 compounds (V₃Si) and on Nb-Ti samples.     

30CrMnSiNi2A钢冷裂纹敏感性研究

对退火状态超高强钢30CrMnSiNi2A进行了大量的插销试验,结果表明:不同缺口位置的插销试样均断裂于熔合区,熔合区是对冷裂纹最敏感的区域;250℃以上预热能明显改善冷裂纹敏感性;同时发现采用光滑插销试样评估超高强钢抗冷裂纹能力是可行的。     

Stirring: The Eckart paradigm revisited

This report provides a topical review of transport in geophysical scale fluids. Rather than presenting an extensive synopsis of the literature, we attempt to connect some recent developments with an incisive 1948 paper by Eckart [1] in which three phases in the evolution of a tracer in turbulent flows were outlined and discussed. The interest here is on the intermediate or stirring phase, which is dominated by the fluid deformation rate. We relate Eckart’s concept of stirring with recent efforts to identify ephemeral spatio-temporal channels that provide a template for transport in geophysical fluid flows. Heretofore such studies have been restricted to a few selected surfaces in the ocean or atmosphere. An application to a large ocean eddy in the Gulf of Mexico illustrates the methodology and shows that the eddy exchanges mass with its environment through material channels identified in the Lagrangian frame by finite-time dynamical systems techniques. We extend previous studies by determining the vertical extent of these transport pathways. The key finding is that the time-dependent geometric structures, which lead to formation of these pathways, retain their coherence well into the water column. Finally, we comment on the significance of these findings on parameterizations of transport processes in predictive models and on the life cycle of ocean mesoscale eddies.     

The C-H delayed failure mechanism revisited

The often cited “Charles–Hillig” model of delayed failure assumes that corrosive attack on existing flaws in glass is controlled by interactions involving the moisture in the environment, which leads to time and stress dependent failure. The analysis by Inglis of the stress multiplication at a rounded end of a flaw is combined with stress-dependent chemical kinetics and thermodynamics. Failure occurs when the tip stress reaches the ultimate strength of the glass. The model provides a physical interpretation of the empirical “Universal Fatigue Law.” When sufficient data is available, it also provides an algorithm that allows a precise determination of the minimum stress needed to induce time-dependent failure. This model is compared with the competing LEFM model.     

Inferencia bayesiana sobre el coeficiente de correlacion de una poblacion normal bivariante

Resumen En el presente artículo, se utiliza el método de maximización de la información desconocida para deducir las distribuciones inicial y final de referencia cuando se trata de hacer inferencias sobre el coeficiente de correlación de una población normal bivariante. Palabras clave: Coeficiente de correlación; Distribución Normal Bivariante; Distribuciones de Referencia; Distribuciones Mínimo Informativas; Inferencia Bayesiana.     

无损压缩技术在测试系统中的应用

针对动态测试中的数据参数进行研究,在深入了解信号特征的基础上,结合当今数据压缩发展的前沿技术,设计、改进得到一种可应用于实际情况、能够满足实际需求的LZW和游程混合压缩算法.设计了基于TMS320F2812 DSP的数据压缩系统.对数据压缩效果进行了测试,试验证明采用该算法能实时、高效的对AD采集到的数据进行压缩.     

30CrMnSiNi2A钢在模拟油箱积水环境中的腐蚀行为研究

通过分析探讨腐蚀面积、腐蚀失重速率、模拟油箱积水中的溶解氧含量和pH值、材料表面腐蚀电位等变化,研究了30CrMnSiNi2A高强钢在模拟油箱积水环境中的腐蚀行为。研究发现:30CrMnSiNi2A高强钢在模拟油箱积水中的腐蚀可分为三个阶段:快速腐蚀阶段(0～24h),腐蚀面积小,腐蚀速率快;中速腐蚀阶段(24～168h),腐蚀面积大,腐蚀速率相对减慢;慢速腐蚀阶段(168～480h),发生全面腐蚀,腐蚀产物的大面积覆盖使得腐蚀速率缓慢。随着腐蚀的进行,模拟油箱积水中的溶解氧含量从开始的逐渐减少到保持稳定;pH值从开始的迅速增大到小幅度波动变化;腐蚀电位在整个腐蚀过程中呈指数函数递减变化。另外,电化学交流阻抗谱和Tafel极化曲线测试结果表明,30CrMnSiNi2A钢在三个特征pH值处的腐蚀速率快慢为V4.2>V4.8>V5.2。     

The computational modeling of nonequilibrium thermodynamics of the martensitic transformations

A mathematical model describing the thermodynamic properties of martensitic crystals is introduced. The thermodynamic model uses the elastic energy derived from the Ericksen-James theory and it incorporates a heat-flux which couples the temperature gradient with the underlying lattice structure. The presented numerical computations simulate thermal effects during the development of the martensitic lamellae from an unstable deformation of the martensitic crystal. The micro-thermal structures are observed to accompany the development of the martensite.     

5A30铝合金弥散析出相研究

本文系统研究了5A30铝合金的微观组织。结果表明,该合金显微组织中的弥散析出相并非通常认为的富Mg的β相,而是Al6Mn和Al4Mn两种富Mn相;真正的β相数量很小,其形态与富Mn相区别明显。