具有两级外差解调的布里渊光纤温度、应力传感器

文章介绍了利用光纤布里渊散射原理检测温度、应力的分布式光纤传感器的工作原理和系统构成,在常用信号解调方式的基础上,提出了新的信号解调方案,实现布里渊频谱信息的提取,并对方案的特点和信号解调方法进行了介绍。     

有源光纤式流量传感器的研究进展

光纤式有源流量传感器是近年来发展起来的一种基于光纤传感技术、流量检测技术的新型流量传感器.目前,主要将金属薄膜的光热转换效应或电阻的热效应与光纤及光纤光栅的温度、应力特性(在流体环境下光的强度、频率、波长及相位等受温度、应力调制的特性)相结合并制得一类新型的光纤有源流量传感器,包括光纤光栅点式及光纤散射(布里渊、瑞利)分布式有源流量传感器.通过文献综述的方式来介绍有源光纤式流量传感器的工作原理、种类及其研究进展,旨在为今后研究提供方法.     

一种新型解调法的光纤布里渊温度传感系统

在基于瑞利散射和布里渊散射强度解调的分布式光纤布里渊温度传感系统中,为了抑制系统温漂和光纤中的应力等噪声因素影响,提出了采用最近已知温度分布曲线来解调待测温度分布曲线的新方法,并在设计的传感系统中进行了实验.实验结果表明,采用该解调法的分布式光纤布里渊温度传感系统能有效提高测温精度和稳定性,降低了系统的成本.系统的测温精度达到±0.09 K.     

分布式光纤传感技术应变测量试验研究

基于布里渊散射原理的布里渊光时域反射技术利用布里渊散射光的光谱技术和光时域测量技术,可对光纤沿线的温度、应变进行分布式监测。通过试验研究了分布式光纤传感技术在应变测量中的空间分辨率、应变分辨率、应变测量精度。研究结果表明,分布式光纤传感技术应变测量能够较准确地测得被测量结构上任何一点的应变,空间最小分辨率0.1m,应变测量分辨率和精度满足工程监测要求,可以在工程监测中作为一种新型分布式应变监测技术加以推广。     

分布式光纤温度传感器新测温原理的研究

介绍了分布式光纤温度传感器的工作原理和应用状况,分析了光纤中放大的自发拉曼散射现象及其时域特性.提出了一种基于光纤中放大的自发拉曼散射光脉冲信号温度效应的新温度测量原理,并将其应用于分布式光纤传感器系统,进而讨论了基于新测温原理的实验现象和实验数据.     

小波滤噪在布里渊光纤传感技术中的应用

针对布里渊分布式传感技术在实际工程应用中的测试信号受外界环境干扰从而影响测试精度的问题,本文提出采用小波信号处理方法对布里渊分布式光纤传感技术的实测信号进行滤噪处理,并以基于布里渊光纤传感技术的实体智能拉索的应变测试数据进行了验证.实验结果表明,该信号处理方法可以有效的消除测试应变中的噪声,提高了索力测试精度,滤噪前后拉索总平均测试索力相对于控制索力的最大相对误差分别为8.8%和5.1%,适合对含噪布里渊传感测试信号进行的滤噪处理.     

光纤在土木工程中的应用

本文介绍了光纤传感器在土木工程应力场、应变场或速度场、温度场测试中的应用情况。介绍了分布式光纤压力传感器，变形测量传感器，光弹式压力传感器和光纤阵列传感方式及其在土木工程的应力、应变及速度测试当中的应用。以及在结构主动抗震的人工神经网络系统中的应用。及其发现前景的展望。     

光纤在土木工程中的应用

本文介绍了光纤传感器在土木工程结构测试、智能结构和智能材料中的应用情况。介绍了Ｂｒａｇｇ光栅光纤传感器,Ｆａｂｒｙ－Ｐｅｒｏｔ（ＦＰ）光纤传感器,高双折射光纤传感器和分布式光纤传感器,以及应用和北们测试的形式,及其发展前景的展望。     

布里渊光纤陀螺光纤环形腔研究

提出了一种用于布里渊光纤陀螺的光纤环形腔设计方法。在分析了布里渊光纤陀螺原理的基础上,利用琼斯矩阵光学的理论以及光纤中的受激布里渊散射理论,详细研究了布里渊光纤环形腔的特性。通过对腔内外光强的细致分析,得出布里渊光纤陀螺环形腔对于腔的耦合系数及输入光强的要求。实验结果表明,该方法用于设置布里渊光纤陀螺工作点,能够保证斯托克斯光的最大传输效率,并有效抑制光路中的散粒噪声。     

海底电缆运行状态监测技术研究

新型海底光纤复合电力电缆(光电复合海底电缆)的出现,使同时传输电能和光信号成为可能,它是近年来海缆整体发展的趋势,也为海缆运行状态监测技术带来了跨领域的突破契机。该文主要介绍基于瑞利散射和布里渊散射的光时域反射(OTDR)技术对扰动、温度和应变敏感的技术特性,并利用上述特性通过分布式光纤传感技术构建监测系统,实现了对海底电缆扰动、温度和应变的长距离分布式运行状态的监测。     

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.     

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.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.