窄带光谱滤光法探测低温黑体太赫兹辐射

为了准确探测低温黑体的太赫兹辐射,研究了黑体的红外辐射和太赫兹各波段辐射的差异,构建了低温黑体太赫兹辐射探测装置,提出在该装置中采用窄带光谱滤光法抑制红外辐射和透过窄带太赫兹光谱.根据普朗克公式计算并对比了各波段太赫兹辐射及红外辐射的亮度值,理论数据显示223～323 K的低温黑体的红外辐射亮度是太赫兹辐射亮度的4～10倍.将在某一窄波长带宽范围内具有高透射比的太赫兹窄带光谱滤光片放置在黑体太赫兹辐射装置的探测器前,滤除红外辐射,并对黑体的太赫兹辐射量进行光谱分段探测实验.根据实验结果计算了黑体在不同太赫兹窄波段的辐射探测值的标准偏差,并对实验结果与黑体太赫兹辐射亮度理论计算值进行了比较.结果显示,窄带光谱滤光法可以实现低温黑体的太赫兹窄带辐射亮度探测.     

太赫兹技术对营养品中蛋白质含量的研究

采用太赫兹时域光谱(THz-TDS)和红外光谱分析技术,研究了3种奶粉、杏仁粉和白砂糖的光学性能和光谱特性。通过对比样品在1658 cm-1和1747 cm-1处的红外光谱吸收峰,可以判定蛋白质和脂肪含量的差别。对比样品在THz波段的吸收系数和折射率,蛋白质含量较高的样品其吸收系数和折射率较高。观察样品的红外吸收峰强度和位置难以定量分析样品的蛋白质含量,但可以利用样品在THz波段的吸收系数与折射率有效地判定营养品中蛋白质的含量。实验结果表明蛋白质在太赫兹波段比在红外波段有更好的区分性,THz-TDS技术有望为营养品中蛋白质含量检测提供一种有效的分析手段。     

基于太赫兹光谱的人参和西洋参鉴别

为了快速区分人参和西洋参,依据两者所含的人参皂苷在太赫兹波段具有不同指纹光谱,提出了一种基于人参皂苷的太赫兹光谱鉴别人参和西洋参的方法。采用MATLAB软件识别人参和西洋参的太赫兹光谱,同时根据太赫兹光谱特征并通过标准的主成分分析(PCA)区分出人参、西洋参。实验结果表明,基于太赫兹光谱的主成分分析可精确区分出人参、西洋参,并且还可以应用于其他类似物质的区分中。     

基于太赫兹光谱的天冬氨酸结构分析及鉴定

太赫兹时域光谱技术（THz-TDS）是一种新的远红外波段光谱测量技术,对化合物结构上的微小差异变化十分敏感,因此成为物质分析与检测的新型方法。文章基于太赫兹时域光谱技术的测定方法,在氮气环境中考察不同来源天冬氨酸在太赫兹波段的吸收特性,并结合差示扫描量热仪（DSC）和傅立叶变换红外光谱仪（FITR）进一步验证THz测定结果的有效性。实验结果表明,用太赫兹时域光谱技术可以清楚地分辨出不同结构天冬氨酸的差异,方法简单,快速,准确。     

基于LabVIEW的太赫兹时域光谱数据处理

太赫兹波段位于红外与微波之间。太赫兹时域光谱技术是一种随着超快激光技术的发展而新兴的、非常有效的相干探测技术,其应用前景已为世界公认。目前各实验室使用的多是基于MatLab和Origin软件处理太赫兹光谱实验数据,但这难以与数据采集程序相结合,所以迫切需要一种更加简便快捷的数据分析手段以适应太赫兹技术的发展。LabVIEW作为一种图形化编程语言具有许多优势。本文概述了太赫兹技术及太赫兹时域光谱,介绍了利用LabVIEW提取太赫兹时域光谱数据并进行分析的方法,通过实例并与其它两种工具处理的结果进行了比较,三种方法的结果完全吻合,证明了这种方法的可靠性。与数据采集程序相结合,我们的工作为太赫兹光谱实验提供了有力的数据分析工具。     

煤炭中氢含量与挥发分的太赫兹时域光谱研究

本文应用太赫兹时域光谱技术(THz-TDS)研究了具有一系列不同氢含量和挥发分的煤炭标准物质在太赫兹波段的光学性质.结果表明,煤炭样品的氢含量与挥发分在太赫兹波段内的吸收系数和介电常数实部均存在负线性关系,符合成矿理论中氢含量与挥发分的真实关系,预示了太赫兹波谱技术将在煤质氢含量及挥发分的研究方面提供了高效的实验方法.     

汽油中烃类物质的太赫兹时域光谱研究

本文应用太赫兹时域光谱技术研究了在室温氮气环境下催化裂化汽油中芳烃、烯烃的光学性质,以芳烃中二甲苯、均三甲苯及烯烃中二异丁烯为例,分析了含有不同浓度二甲苯、均三甲苯和二异丁烯的催化裂化汽油在太赫兹波段的光谱效应。结果表明,汽油中不同浓度的芳烃和烯烃具有不同的吸收谱和折射率特性。根据太赫兹光谱包含的特征信息能够对汽油中芳烃、烯烃成分进行定性分析,从而为汽油中烃含量的定量检测做基础。     

环氧树脂及其混合物的太赫兹光谱分析

本文采用太赫兹时域光谱（THz-TDS）技术研究了四种不同环氧值的环氧树脂在0.2～2.6 THz波段的光学性能和光谱特性,并通过计算获得了四种树脂的吸收系数和折射率。同时,基于四种环氧树脂的吸收谱,本文还对三种按不同质量百分数混合的环氧树脂混合物的太赫兹吸收光谱进行分析。实验结果显示,四种环氧树脂在太赫兹频率范围内没有明显的吸收峰,但各个样品吸收曲线和折射率曲线有显著的差异。运用最小二乘拟合的方法对混合物的吸收谱进行拟合,拟合得到的混合物吸收谱与实验所得的结果相符合。因此,根据太赫兹光谱包含的特征信息能够对混合物进行分析,证实了太赫兹波谱技术将在定量分析领域具有潜在的应用前景。     

太赫兹双梳光谱中重复频率差影响的研究

太赫兹双梳光谱技术因其高频率分辨率和高灵敏度等优点,近年来成为一种有力的光谱测量技术。为了提高光谱系统的探测性能,本文分析了双梳光谱技术在时域和频域中的采样原理及方法,基于两台飞秒激光器搭建了一套重复频率可调的太赫兹双梳光谱系统。通过改变一台光频梳的重复频率,系统地研究了不同重复频率差对太赫兹双梳光谱系统性能的影响。结果表明有效范围内的重复频率差越小,探测到光谱质量越高。当重复频率差为10 Hz时,太赫兹双梳光谱系统的探测性能最佳。此研究为太赫兹双梳光谱技术选择最合适的重复频率差提供了方法。     

基于太赫兹光谱技术的抗生素类药物检测研究

本文利用太赫兹时域光谱技术在室温下对几种在临床和人们日常生活中常用的抗生素类药物阿莫西林、青霉素钠、头孢氢氨苄和头孢拉丁进行了光谱测量,获得了四种物质在0.2-1.7THz波段的吸收谱和折射谱,发现这四种抗生素类药物在太赫兹波段均存在明显的特征吸收峰,可作为其在太赫兹波段的指纹谱用于药物分子识别。本研究表明,太赫兹时域光谱技术在常用抗生素类药物的物质鉴别及药品质量检查方面有着广泛的应用前景。     

无导线微型机械驱动器试验研究

针对医用内窥镜驱动系统，提出了一种通过电磁感应加热感应导体、再通过感应导体加热其周围石蜡的无导线热膨胀微型机械驱动器，电磁感应加热不仅加热速度快，而且驱动器与驱动源之间无需导线连接，使驱动器的使用更加方便，石蜡在其熔点附近具有很大的膨胀系数，而且其熔点可以调节（所用石蜡的熔点在37－39℃之间，适合在人体内使用），在对10个不同尺寸的原理性驱动器模型进行位移输出性能试验的基础上，制作了4个可以实现单向运动的驱动器模型，并对其运动性能进行了试验，其最大平均运动速度可以达到0．139mm/s。     

Synthesis of some additives from upgraded petroleum residues of lubricant oil refineries

Aromatic extract residues occur as by‐products in petroleum refineries, through the process of refining lubricant oil. These residues are considered as having low economic value, and their disposal may even cause problems for the refineries. The present work looks at upgrading these residues by using them to synthesise different petroleum additives, e.g., antioxidants, ashless dispersants, pour‐point depressants, and flow improvers for lubricating crankcase oils and for fuels. The antioxidants were synthesised by reacting mono‐aromatics with phosphorus pentasulphide (P₂S₅) in the presence of zinc oxide (ZnO). Ashless dispersant additives were synthesised by reacting alkylated mono‐aromatics (using chlorinated paraffin wax as an alkylating agent) with formaldehyde solution (37%) in the presence of polyisobutylene succinimide. Fuel pour‐point depressants and flow improvers can be synthesised by acylating di‐aromatics via a Friedel‐Crafts reaction. Comparative evaluation of the synthesised products with commercial additives showed them to have good comparative performance properties.     

In situ high resolution electron microscopy/electron energy loss spectroscopy observation of wetting of a Si surface by molten Al

Electron energy loss spectroscopy was used to observe the segregation of Al on a Si surface above the melting point of Al. A mixture of Al and Si particles was heated above the melting point of Al in a vacuum of 1 × 10⁻⁵ Pa. The Si surface, which initially had been covered with an amorphous oxide layer before heating, became clean and atomically facetted when the Al melted. It was shown that the Si surface was segregated with Al.     

基于管道检查用微型机械驱动器试验研究

提出了一种通过电磁感应加热感应导体 ,再通过感应导体加热其周围石蜡的无导线热膨胀微型机械驱动器。电磁感应加热不仅加热速度快 ,而且可以实现驱动器与驱动源之间的无导线连接。石蜡在其熔点附近具有很大的膨胀系数 ,而且其熔点可以调节。在对 7个不同尺寸的原理性驱动器模型进行位移输出性能试验的基础上 ,制作了 4个可以实现单向运动的驱动器模型 ,并采用气冷和水冷两种冷却方式对其运动性能进行了试验研究 ,其最大平均运动速度可以达到 0 .13 9mm/s。     

Heat transfer characteristics in latent heat storage system using paraffin wax

An energy storage system has been designed to study the heat transfer characteristics of paraffin wax during melting and solidification processes in a vertical annulus energy storage system. In the experimental study, three important issues are focused. The first one is temperature distribution in the phase change material (PCM) during the phase change processes. The second one is the thermal characteristics of the paraffin wax, which includes total melting and total solidification times, the nature of heat transfer phenomena in melted and solidified PCM and the effect of Reynolds number as inlet heat transfer fluid (HTF) conditions on the heat transfer parameters. The final one is to calculate heat transfer coefficient and effectiveness during solidification process. The experimental results proved that the PCM melts and solidifies congruently, and the melting front moved from the top to the bottom of the PCM container whereas the solidification front moved from bottom to the top along the axial distances in the PCM container. Experiment has been performed for different water flow rates at constant inlet temperature of heat transfer fluid for recovery and use of heat. Time-based variations of the temperature distributions were explained from the results of observations of melting and solidification curves. Charging and discharging processes were carried out. Heat transfer characteristics were studied.     

高导热能力的蓄热装置传热性能研究

固液相变材料的导热系数极低,往往不能在规定时间内完全相变融化以吸收电子设备工作的热负荷,导致电子设备出现局部超温现象。文中采用数值仿真和试验测试的方法对高导热能力蓄热装置进行研究。采用均温板与蓄热装置一体化设计,均温板将点热源转换为面热源消除了电子产品温度峰值导致局部超温的问题,也增加了相变材料的吸热面积。同时在相变材料中设置铝合金板以及铝合金波纹板。通过上述设计,增大了石蜡的当量导热系数,增加了短时间内石蜡的融化量进而提高了蓄热能力。     

铝合金/钢异种材料熔钎焊接工艺及其研究现状*

铝合金/钢复合结构以具有重量轻、综合性能高等优势在汽车、航空航天、石油石化、电力、船舶等行业具有广泛的应用前景。但二者之间巨大的理化性能差异,使铝合金/钢板异种金属的焊接仍然存在诸多问题。熔钎焊接工艺是基于母材之间存在的熔点差异,通过精确控制焊接热输入,在确保高熔点母材不熔化的前提下,让低熔点母材和填充金属熔化形成熔焊接头,并与未熔化的高熔点母材形成钎焊连接接头,是适合铝合金/钢复合结构优质高效制备的合适焊接工艺。通过对国内外对铝合金/钢熔钎焊接工艺、接头组织性能调控等方面研究现状的综合评述,讨论了铝合金/钢熔钎焊接技术存在的问题,并对铝合金/钢熔钎焊接技术工程化应用所采取的措施进行阐述。     

An explanation of the hardness differential needed for abrasion

To interpret metallurgical transformations on a worn surface or in wear particles, a new theory is postulated: the melting temperature tends to be depressed when shear stress is applied to the material. Experimental investigation revealed that the freezing point of liquids is depressed in a shear field. The freezing points of paraffin and gallium were measured in a rotating viscometer. In the rotating state of the viscometer, the freezing point of these liquids was depressed. A difference in the freezing behaviour was observed between the static and the rotating state. From these facts, it is suggested that the metallurgical structures in a wear system can be transformed even if the frictionally induced temperatures do not reach the theoretical value required for transformation according to the phase diagram.     

Steedman's polyester wax embedment and de-embedment for combined light and scanning electron microscopy

Steedman's polyester wax mixture is a good, general-purpose histological embedding medium that is suitable and convenient to use when it is desirable to combine light microscopy with scanning electron microscopy (SEM). A range of properties recommend this wax: it has a low melting temperature (37°C), is readily soluble in most dehydrating agents, results in negligible tissue shrinkage, preserves tissue antigenicity, and may even be used as a solvent for fixative agents. We prepare and embed tissues in polyester for light microscopy much as they would be for paraffin wax. For SEM, the block surface is micro- or ultraplaned, utilizing, respectively, a standard rotary microtome with razor blade knives or an ultramicrotome with glass knives. The block is de-waxed in absolute alcohol and then taken to critical point drying. Similarly, sections mounted on coverslips or glass slides may be brought to the SEM after removing the wax. This enables one to bring to the SEM relatively large block faces or sections with good control over orientation. We find the results to be superior to similar procedures employing paraffin. We believe it to be more versatile and equivalent or superior to a variety of other techniques designed to gain access to the interior of tissues with SEM.     

豆油脂肪酸修饰二氧化钛纳米微粒的摩擦学性能研究

采用表面修饰化学法制备了豆油脂肪酸修饰的二氧化钛纳米微粒,对所制备的纳米微粒通过红外光谱进行了结构表征。将二氧化钛纳米微粒作为润滑油添加剂,加入液体石蜡中,利用四球试验机考察其摩擦学性能。试验结果表明,有机基团修饰的二氧化钛纳米微粒具有优良的分散性,可提高液体石蜡的抗磨性和承载能力;加有表面修饰的二氧化钛纳米微粒的液体石蜡磨斑直径减少了39%,承载能力能够提高1倍以上。