几种加氢裂化催化剂的太赫兹光谱研究

采用太赫兹时域光谱(THz-TDS)方法,本文研究了几种Y型加氢裂化催化剂(NaY、ReY、USY和HY)在0.2-1.2THz频段的光谱特性.与此同时,对其中的NaY分子筛进行了加热处理,测量了其经过不同温度处理后的太赫兹时域光谱.通过快速傅里叶变换,分别得到了不同种类和不同温度处理后催化剂的太赫兹吸收谱和折射率谱.研究结果表明,太赫兹时域光谱技术既能用于催化剂的种类鉴别和性能表征,又能给出不同温度下催化剂本身内部结构变化对应的太赫兹光谱响应.本研究工作的展开,证明了太赫兹方法用于催化剂性质表征的可行性,对太赫兹技术在催化领域的应用具有一定的指导意义.     

太赫兹技术在果蔬快速检测设备中的应用分析

太赫兹技术在果蔬快速检测中有着独特的优势,而太赫兹辐射具有非常重要的科学研究和应用价值。首先分析了太赫兹光谱检测技术,包括太赫兹时域光谱技术和太赫兹成像技术,接着分析了太赫兹技术在果蔬快速检测设备中的应用。太赫兹技术为果蔬快速检测提供了一种新的检测方法。     

Fe、Cu、Al三种金属狭缝的THz光谱测量

本文利用太赫兹时域光谱技术研究了宽度在0．08mm-1mm的Fe、Cu、Al三种不同金属狭缝在0．2-1．5THz频段的光学性能,得到了三种样品的时域谱、频域谱、透过率谱,并对三种谱图进行了比较。结果表明金属狭缝对太赫兹波的响应只与狭缝宽度有关,与狭缝深度和材料本身关系不大。这种方法可以不必考虑产生狭缝裂纹的金属材料本身种类,为以后运用太赫兹技术实现对不同金属、异类金属焊缝、合金管道无损检测奠定基础。     

基于太赫兹技术的锂电池电极涂层质量检测

为了对锂电池的电极涂覆层材料厚度以及均匀性进行无损检测,弥补传统检测方式辐射性强、对检测人员伤害大以及太赫兹远场成像分辨率低的缺点,设计研制了一套测量探头能够灵活移动的太赫兹近场光谱检测系统。采用太赫兹微米探针和利用近场技术对涂覆层进行探测,实现了微米级检测。检测结果表明,本系统能够发现传统β射线和X射线等检测手段无法识别到的厚度不均匀缺陷,可为锂电池电极涂覆层的质量检测提供一种高分辨率的、快速的太赫兹无损安全检测手段。     

太赫兹光谱技术在药物定性定量检测上的应用

为判断药物的真伪,检查药物的纯度,以及克服目前化学药物定性定量检测中耗时长、损耗样本、操作繁琐等缺陷,提出了一种基于太赫兹光谱技术的快速且能准确定性和定量药物的检测方法。基于太赫兹吸收光谱,提取了氯雷他定、消旋卡多曲的特征峰频点以及峰下面积差特征,并通过这些信息来对药物进行定性与定量检测。实验结果表明：在定量检测中,太赫兹光谱技术具有高的稳定性及检测精度;质量分数梯度变化的线性拟合相关系数达到99.8%;在结合主成分分析法（principal component analysis,PCA）对其他药物的检测中,太赫兹光谱技术定性检测准确率可达100%,定量检测误差小于0.01。这些结果可为后续药物的快速、准确和无损检测提供参考。     

碳纳米管技术首次检测出太赫兹光子对开发高灵敏度检测仪器具有重要意义

光有X光、红外线、紫外线等很多种类，其中最受科学家关注的是“太赫兹光”。太赫兹光不仅能够观察无法看见的分子的运动，还可以用于癌症检查等，用途十分广泛。但迄今为止，人类对太赫兹光的检测以及产生这种光源都非常困难，属于未知领域。     

基于太赫兹波谱的液体极性测量

太赫兹波能与极性液体的氢键发生强烈的共振吸收作用,分子极性越大,吸收作用越强。基于此特性,在0.2～1.0 THz波段利用太赫兹时域光谱技术对甲醇、乙醇、正丙醇、正丁醇四种一元醇液体的极性进行检测研究。根据测量得到的四种液体太赫兹波谱数据,得出了液体的极性与其太赫兹波谱的关系式,再利用此关系式求得四种液体的计算值。通过对四种液体极性的标准值和计算值比对,验证了所得液体极性求取公式的有效性。研究结果表明,四种不同液体的时域光谱因分子的极性差异有显著的不同,所用的液体极性测量方法能够对液体的极性进行快速有效的检测与鉴别,可为其他液体极性的检测提供参考。     

消息

碳纳米管技术首次检测出太赫兹光子对开发高灵敏度检测仪器具有重要意义光有X光、红外线、紫外线等很多种类,其中最受科学家关注的是“太赫兹光”。太赫兹光不仅能够观察无法看见的分子的运动,还可以用于癌症检查等,用途十分广泛。但迄今为止,人类对太赫兹光的检测以及产生这种光源都非常困难,属于未知领域。光具有波和粒子两重特性。日本理化学研究所石桥幸治主任研究员领导的研究小组利用“碳纳米管”的微小结构在世界上首次检测出太赫兹光子。在天然原子中,围绕原子核的电子具有分散的能量。把电子封闭在直径数纳米的碳纳米管内,电子就…     

柴油十六烷值测定机的研究

国内对压缩比法测量柴油十六烷值方法研究较少,而该方法是在柴油评定出现纠纷之后唯一的仲裁方法.应用该方法设计的柴油十六烷值测定机市场基本被美国WAUKESHA公司所占有,为实现柴油十六烷值测定机国产化,对柴油十六烷值测定机进行了研究.经过对柴油从建压、喷射到压燃过程的时序分析,设计柴油十六烷值测定机电控喷油系统、喷油爆震...     

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。     

柴油醇的燃料性质和排放特性

为解决柴油醇在应用中存在的相分离、十六烷值低下等问题,提出一种由中碳醇 低分子醚 高分子聚合物 有机硝酸酯构成的复合添加剂.结果表明:添加1%～2%容积百分比的复合添加剂后,柴油醇的溶解度明显提高;并且发动机的冷启动试验也表明加入复合添加剂后,柴油醇的着火性能己同于柴油的水平.由发动机台架试验还研究了柴油和不同乙醇掺合率的柴油醇给与发动机的燃料经济性、排气烟度和THC、CO、NOx气体排放的影响.结果表明:柴油醇以重量计的比油耗较柴油的相应地增加,但以能量计的有效热效率却较柴油的略有提高;各种乙醇掺合率下的排气烟度都大幅地降低;NOx排放浓度则随负荷增加而逐渐增大,但在高负荷工况时,随乙醇掺合率的增加,NOx排放浓度呈下降趋势.     

Flammability of New Diesel Fuels

Analytical evaluation of the flammability of alternative and blended fuels is considered. A method is proposed for determining the cetane number and ignition delay for fuels and the combustion characteristics in diesel engines.     

添加剂对轻柴油燃料润滑性能影响的研究

叙述了柴油中流动改进剂及十六烷值改进剂对润滑改进剂的影响。流动改进剂与润滑改进剂相互抑制，十六烷值改进剂能够降低润滑改进剂的添加效果。     

EFFECTS OF COOLED EXTERNAL EXHAUST GAS RECIRCULATION ON DIESEL HOMOGENEOUS CHARGE COMPRESSION IGNITION ENGINE

The effects of cooled external exhaust gas recirculation (EGR) on the combustion and emission performance of diesel fuel homogeneous charge compression ignition (HCCI) are studied. Homogeneous mixture is formed by injecting fuel in-cylinder in the negative valve overlap (NVO) period. So, the HCCI combustion which has low NOx and smoke emission is achieved. Cooled external EGR can delay the start of combustion effectively, which is very useful for high cetane fuel (diesel) HCCI, because these fuels can easily self-ignition, which makes the start of combustion more early. External EGR can avoid the knock combustion of HCCI at high load which means that the EGR can expand the high load limit. HCCI maintains low smoke emission at various EGR rate and various load compared with conventional diesel engine because there is no fuel-rich area in cylinder..     

The effect of biodiesel and ultra low sulfur diesel fuels on emissions in 11,000 CC heavy-duty diesel engine

It seems very difficult to comply with upcoming stringent emission standards in vehicles To develop low emission engines, better quality of automotive fuels must be achieved Since sulfur contents in diesel fuels are transformed to sulfate—laden particulate matters as a catalyst is applied, it is necessary to provide low sulfur fuels before any Pt-based oxidation catalysts are applied In general, flash point, distillation 90% and cetane index are improved but viscosity can be worse in the process of desulfunzation of diesel fuel Excessive reduction of sulfur may cause to degrade viscosity of fuels and engine performance in fuel injection systems This research focused on the performance of an 11,000 cc diesel engine and emission characteristics by the introduction of ULSD, bio-diesel and a diesel oxidation catalyst, where the bio—diesel was used to improve viscosity of fuels in fuel injection systems as fuel additives or alternative fuels     

ZrTe5的太赫兹辐射研究

为了研究层状ZrTe₅（五碲化锆）在飞秒脉冲激发下的超快瞬态太赫兹辐射,利用太赫兹时域反射系统对其进行了测试分析。通过分析层状ZrTe₅太赫兹电场幅度与飞秒激光泵浦功率及泵浦脉冲偏振关系,获得了层状ZrTe₅产生太赫兹辐射的主要机理。同时还对比了相同泵浦条件下层状ZrTe₅和本征GaAs（砷化镓）太赫兹辐射强度。研究表明,层状ZrTe₅具有带隙结构窄、吸收深度浅、光生电子剩余能量较大、载流子迁移率较高等优势,在太赫兹产生方面比传统半导体具有更好的性能。该研究可为发现高效、高度集成化太赫兹辐射源提供参考。     

双色激光场下太赫兹辐射能量的调控研究

提升太赫兹(THz)脉冲产生能量一直是近些年超快光学的研究热点之一。基于双色激光在空气中拉丝产生THz波的数值模型,在隧穿电离范围内,详细分析了双色激光场产生THz波的最佳参数组合以及其产生变化的物理机理,用于得到最强的THz波辐射能量。双色激光场组合的电场具有不对称性,其引起的快速振荡有利于电子的加速过程,进而产生更大电子数密度以及在沿拉丝距离形成了更强的累积净电流。当电子密度和净电流增加时,使得单点THz辐射更强,拉丝各点辐射的THz波相干叠加,于是在远场得到了更强的THz波能量。这些研究结果为不同激光产生条件下增强THz波辐射能量提供了详尽的参数分析及理论依据,重点研究了不同寻常波长组合及不同相对相位对激光拉丝产生太赫兹波的影响,对后续大幅增强THz辐射效率具有重要意义。     

Investigation of soot formation in a D.I. diesel engine by using laser induced scattering and laser induced incandescence

Soot has a great effect on the formation of PM (Paniculate Matter) in D.I. (Direct Injection) Diesel engines. Soot in diesel flame is formed by incomplete combustion when the fuel atomization and mixture formation were poor. Therefore, the understanding of soot formation in a D.I. diesel engine is mandatory to reduce PM in exhaust gas. To investigate soot formation in diesel combustion, various measurements have been performed with laser diagnostics. In this study, the relative soot diameter and the relative number density in a D.I. engine was measured by using LIS (Laser Induced Scattering) and LII (Laser Induced Incandescence) methods simultaneously which are planar imaging techniques. And a visualization D.I. diesel engine was used to introduce a laser beam into the combustion chamber and investigate the diffusion flame characteristics. To find the optimal condition that reduces soot formation in diesel combustion, various injection timing and the swirl flow in the cylinder using the SCV (Swirl Control Valve) were applied. From this experiment, the effects of injection timing and swirl on soot formation were established. Effective reduction of soot formation is possible through the control of these two factors.     

The Conduction of Current in Bearings

The mechanism of the action of sulfur compounds during boundary lubrication has been studied by using S³⁵ as a tracer. A NACA type friction machine was used to study the chemical reaction between elementary sulfur or sulfur compounds and metals. All additives were added to cetane which was used as a lubricating oil.

It has been found that it is possible to study kinetically the formation of the iron sulfide and the rate of the wear of its film on the friction surface. Some good analytical results have been obtained.

The rate of wear of iron sulfide film for benzyl disulfide is lower than that for the elementary sulfur, because the former may adsorb effectively to the worn surface. The iron sulfide film formed on the friction surface seems to absorb the polar compounds more actively than the surface of iron oxide. These results Were revealed from the autoradiography of the adsorption.