基于遗传算法的水声信道常模类盲均衡算法研究

为了解决CMA盲均衡算法收敛速度缓慢、稳态误差大的问题,考虑到初始化权值对CMA算法的重要影响,利用了遗传算法对CMA算法进行有效改进,引入了小样本重用的思想,给出了一种新的适用于水声信道的常模类盲均衡算法,计算机仿真研究证明,该算法不仅大大加快了收敛速度,而且有效的降低了稳态误差。     

盲信道均衡的动量恒模算法

介绍了盲信道均衡恒模算法（CMA）的基本原理，对恒模算法的缺点进行了分析，通过修正恒模算法的迭代公式提出一种动量恒模算法（MCMA）。利用QPSK信号，采用计算机仿真的方法对动量恒模算法与恒模算法进行盲均衡性能比较，模拟结果显示，MCMA算法比CMA算法在收敛速率、降低稳态均方误差和符号间干扰具有明显的优势，有效地改进了信道均衡性能。     

判决引导和常数模融合盲均衡算法研究

结合判决引导（DD：Decision-Directed）算法和常数模算法（CMA：Constant Modulus Algorithm）的各自优点,研究了一种基于DD和CMA的融合盲均衡算法。DD算法收敛速度快,但要求初始接收信号眼图张开,CMA算法稳健,但是收敛速度慢,为此,对接收信号依DD算法和CMA算法获得瞬时误差后进行加权融合处理,以加权后获得的瞬时误差对均衡器权系数进行调节,实现均衡。计算机仿真证明了融合盲均衡算法有效提高收敛速度的同时具有良好的稳健性和均衡性能。     

VS-MFxLMS算法及其在汽车车内噪声有源控制中的应用

为提高经典VS-FxLMS算法的收敛性能以及规避MFxLMS算法不能同时兼顾收敛速度和稳态误差的缺陷,结合修正反正切函数和归一化的方法,提出了一种可用于汽车车内噪声有源控制的VS-MFxLMS算法。应用MFxLMS算法、VS-FxLMS算法和VS-MFxLMS算法分别进行汽车车内噪声有源控制仿真实验。噪声有源控制结果的比较表明,与MFxLMS算法相比,VS-MFxLMS算法的收敛速度提高1.5倍以上,稳态误差降低55%以上;与VSFxLMS算法相比,VS-MFxLMS算法的收敛速度提高25%以上,稳态误差降低28%以上,这为汽车车内噪声的有源控制提供一种新方法。     

VS-MFxLMS算法及其在汽车车内噪声有源控制中的应用

为提高经典VS-FxLMS算法的收敛性能以及规避MFxLMS算法不能同时兼顾收敛速度和稳态误差的缺陷，结合修反正切函数和归一化的方法，提出了一种可用于汽车车内噪声有源控制的VS-MFxLMS算法。应用MFxLMS算法、VS-FxLMS算法和VS-MFxLMS算法分别进行汽车车内噪声有源控制仿真实验。噪声有源控制结果的比较表明，与MFxLMS算法相比，VS-MFxLMS算法的收敛速度提高了1.5倍以上，稳态误差降低55%以上；与VS-FxLMS算法相比，VS-MFxLMS算法的收敛速度提高了25%以上，稳态误差降低了28%以上；为汽车车内噪声的有源控制提供了一种新方法。     

基于改进双曲正切函数的变步长最小平均p范数算法

在信号处理领域,传统的自适应滤波算法采用的固定步长会导致稳态误差和收敛速度无法同时兼顾。针对这个问题,对最小平均p范数(Least Mean p-norm,LMP)算法进行改进,提出了一种基于改进双曲正切(tanh)函数的变步长最小平均p范数算法。该算法利用改进的tanh函数来调节步长,采用移动加权平均法构造变步长函数;同时引入了一个调节函数以进一步提升算法的性能。通过在海洋脉冲噪声干扰下进行仿真,实验表明,与已有的固定步长和变步长算法相比,改进的变步长LMP算法较好地兼顾系统的收敛速度和稳态误差;引入调节函数后的新算法在保证原有算法收敛速度的同时进一步降低了算法的稳态误差,从而兼顾了算法的收敛性和稳定性,具有较好的可行性。     

基于自适应混合结构的快速收敛函数链接人工神经网络算法研究

在非线性主动噪声控制方法中,函数链接人工神经网络(FLANN)算法是最常用的算法之一。FLANN降噪量大,但是其收敛速度较慢。为解决该问题,通过一个自适应混合参数对BFXLMS算法和FLANN算法进行有效结合,提出了CBFLANN算法。在不降低FLANN降噪量的情况下,提高了其收敛速度,解决了FLANN算法无法同时实现快速收敛和低稳态误差的问题。多个仿真实验对提出的CBFLANN算法的降噪性能进行了验证,结果表明,CBFLANN同时拥有BFXLMS的收敛速度和FLANN的降噪量。该算法的提出可以为传统主动噪声控制算法难以同时兼顾收敛速度与稳态误差的问题提供解决方案,具有很强的实际应用价值。     

车内噪声主动控制变步长LMS算法

通过对轨道车辆车内含噪样本数据的分析,应用步长因子μ(n)与误差信号e(n)呈正弦函数关系的变步长LMS算法。分别对自适应滤波器中的权向量按照最速下降算法进行更新,并利用建立的自适应滤波器进行车内噪声主动控制。结果表明,提出的变步长LMS算法解决了LMS算法因固定步长不能同时兼顾算法收敛速度和稳态误差的固有缺陷,具有更快的算法收敛速度和较小的稳态误差。     

汽车车内噪声主动控制变步长NFB-LMS算法

为规避最小均方（Least Mean Square,LMS）算法不能同时提高收敛速度和降低稳态误差的固有缺陷,以及已有变步长LMS算法存在收敛速度慢和稳态误差估计精度差的问题,文中提出了一种基于变步长归一化频域块（Normalized Frequency-domain Block,NFB） LMS算法的汽车车内噪声主动控制方法。为了比较,应用传统的LMS算法、基于反正切函数的变步长LMS算法和变步长NFB-LMS算法分别进行实测汽车车内噪声的主动控制。结果表明,与其他两个算法相比,变步长NFB-LMS算法的收敛速度提高了70%以上,稳态误差减小了90%以上。变步长NFB-LMS算法在处理车内噪声信号时具有很高的效率,为进行汽车车内噪声主动控制提供了一种新方法。     

适用于无线传感器节点的低复杂度CCVSLMS均衡器研究

针对无线传感器节点的均衡算法--最小均方误差(LMS)算法和截断数据LMS算法或截断误差LMS算法(CLMS算法)的收敛速度、稳态误差性能的不足,进行了截断误差和截断数据可变的步长LMS算法(CCVSLMS算法)的研究,该算法通过对误差和数据进行截断处理和建立步长因子μ与截断变化率的线性函数关系来改善收敛速度和稳态误差...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.