基于FBG温度解耦的光纤法布里-珀罗 高温压力传感器

本文提出了一种基于光纤布拉格光栅(FBG)温度解耦方法的光纤法珀(FP)压力传感器,该传感器采用低温共烧陶瓷(LTCC)技术实现批量化制作.通过在膜片式压力传感器的基础上集成光纤布拉格光栅(FBG),实现温度、压力双参数测量;提出温度解耦方法,对传感器进行温度补偿及压力测量结果的修正.实验结果表明,在20～300℃的温度范围内, FBG温度传感器的灵敏度为0.012 nm/℃,在160 kPa的压力范围内,压力测量灵敏度约为0.1μm/kPa, 3次重复实验的重复性误差和非线性误差分别约为5.6%和1.3%,温度系数为0.018μm/℃,压力灵敏度随温度变化为0.283 nm/(kPa·℃),同时,采用温度解耦方法,得到压力计算值与真实值最大偏差小于2.5 kPa.     

翅片管冷凝器低压环境下空气侧换热特性研究

本文通过搭建压力可调的封闭环境仓,实验研究了在40~101 kPa低压环境下,不同的管排数和循环热水温度对翅片管冷凝器空气侧对流换热特性的影响。结果表明:在相同的空气侧雷诺数下,环境压力的降低导致空气侧对流换热减小。当空气侧雷诺数为400时,环境压力从101 kPa降至40 kPa,对流换热表面传热系数随之降低44.1%;随着环境压力的降低,管排数对空气侧对流换热的影响变弱;在低压环境下,改变循环热水温度不会对对流换热表面传热系数产生明显影响。随着环境压力的降低,空气侧的对流换热表面传热系数与常压模型的计算结果偏差增大,当环境压力从101 kPa降至40 kPa时,平均偏差从17.3%增至77.5%。在实验的基础上,本文根据环境压力、管排数对空气侧对流换热的影响,对常压下的翅片管空气侧换热模型进行修正,修正后的平均偏差为9.5%。     

低气压环境试验设备检测结果分析

正在检测低气压环境试验设备的过程中,笔者发现了一个现象:在不同的低气压环境条件下,设备的实测温度与设定温度之间的偏差与气压有关联。下面作简要分析。例如,一台低气压环境设备需要在101.3kPa常压条件下检测-40.0℃和60.0℃两个温度点,同时还需在0.4kPa压力条件下测量这两个温度点。得出的结论:常压下测量低温-40.0℃时,设备的几何中心点实测温度为-40.2℃;在测量温度为60.0℃时,设备的几何中心点实测温度为60.4℃。而在0.4kPa压力条件下测量这两个温度时,设备的几何中心点实测温度分别     

一种可同时测量温度和压力的新型SAW传感器

针对汽车轮胎压力监测系统（TPMS）的典型应用,提出了一种基于声表面波（SAW）的新型传感器.这用SAW延迟线理论,温度和压力对于传感器的影响能够通过射频回波信号的变化反映出来.通过在数据处理中引入权重因子,实现对于温度和压力的准确测量.在一定压力（0-200 kPa）和温度（20-100℃）范围内的测试结果表明,该传感器能够同时准确测量温度和压力.SAW传感器对温度的测量精度可以达到0.05℃,对压力的测量精度可以达到7.2 kPa.在对于可靠性和耐久性具有特殊要求的汽车轮胎压力监测等领域,该传感器简单的结构和无线无源的测量方式,进一步提高了其实用性和推广价值.     

有机小分子在半晶体聚乙烯中的溶解度

通过测定压力的方法研究了乙烯、正己烷和异戊烷在三种不同结晶度聚乙烯中的溶解度,分析了结晶度、小分子物性以及温度对该过程的影响。得到温度60℃~90℃,乙烯0~2 M Pa,正己烷19 kPa~100 kPa,异戊烷80 kPa~300 kPa范围内三者各自在聚乙烯样品中的溶解度数据。结果表明,乙烯溶解度呈线性,符合H enry定律;正己烷和异戊烷的溶解度呈非线性。聚乙烯结晶度20%~72%范围内,有机小分子在聚乙烯中的溶解度随结晶度的增加而减小。溶解度随压力增加和温度的减小而增加。     

基于气体吸收谱线宽度的温度检测方法

本文提出一种用于温度传感的气体吸收谱线宽度检测方法,该方法基于比尔-朗伯定律中气体吸收谱线宽度与温度关系,以特征线宽代替半高全宽(FWHM)进行线宽的测量.研究气体所处环境的温度改变对气体吸收谱线宽度的影响.以乙炔气体为例,在0~90℃的温度范围内,测量了其5条较强吸收谱线的特征线宽变化情况.特征线宽测量值标准差0.6 pm,温度分辨力2℃,稳定性好.此方法有效避免了光源功率的波动对特征线宽测量的影响,提高了线宽测量的准确性,该方法应用于气体温度测量具有可行性.     

全数字开环光纤陀螺工作点实时控制

工作点控制是实用型开环光纤陀螺必须解决的技术问题,为此提出了全数字开环光纤陀螺工作点控制方案。在不增加硬件的情况下,通过提取陀螺信号中的二、四次谐波幅值获得陀螺工作点信号,并作为控制输入量,调整调制信号的幅度,实现对陀螺工作点的实时控制。实验表明,该方案在宽温度范围内使陀螺工作点稳定性达到1.16×10-3,偏差为3.1×10-4,在-40℃到60℃范围内的启动时间小于10s。     

高温高固气质量比条件下旋风预热器换热管压降的研究

为了掌握旋风预热器换热管压降随温度、风速和固气质量比的变化规律,在各种不同条件下,对旋风预热器换热管压降进行测试。结果表明:在气流速度固定不变的情况下,当固气质量比z≤1时,随着温度的升高,压降先增大后减小,在200℃附近出现高点;当固气质量比z≥1.5时,随着温度的升高,压降逐渐减小,在600℃附近趋于平缓,之后随着温度的升高略有增大。压降总是随着风速的提高而增大,随着固气质量比的增加而增大。     

退火工艺对FeCuNbSiB非晶带材压磁效应的影响

研究了退火工艺对非晶FeCuNbSiB带材压磁性能的影响情况.结果表明,当退火温度为300℃时,FeCuNbSiB非晶带材开始慢慢晶化,当温度上升到500℃时,带材内部结构已由非晶态完全转变成晶态.当退火温度＜300℃时,退火能够消除部分内应力,使阻抗变化的灵敏度提高;退火温度高于300℃,随着退火温度的升高,压磁效应减弱.退火时间高于1h,带材的压磁性能变化不显著.非晶FeCuNbSiB带材经过100℃×2h退火,压力为2.7MPa时,阻抗变化最高可达40Ω.     

氧气在 PVDF 片材中扩散的分子动力学模拟

目的研究气体在PVDF片材中的扩散。方法采用分子动力学模拟方法研究了氧气在其片材中的扩散行为,得到氧气在PVDF片材中的扩散系数,并讨论了时间、聚合度、温度及残余压力对扩散系数的影响。结果模拟时间太短对模拟结果不利,应以大于1000 fs为宜。当聚合度由400增加到800时,扩散系数由4.77×10-6cm2/s下降到1.78×10-6cm2/s;当温度从298 K提高到303 K时,扩散系数由1.06×10-6cm2/s增加到1.42×10-6cm2/s;当残余压力由60 kPa增大到100 kPa时,扩散系数由7.07×10-6cm2/s下降到3.06×10-6cm2/s。结论氧气在PVDF片层中的扩散系数随聚合度和残余压力的增大而变小,随温度的提高而变大。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

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 Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

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.