莽吉柿中几种双苯吡酮和蒽醌类成分的分离与鉴定

对莽吉柿(Pericarpium Garciniae Mangostanae)85%乙醇提取物进一步分离,得到8个双苯吡酮类化合物和1个蒽酮类化合物,经理化性质和NMR及MS谱学数据鉴定分别为α-倒捻子素-3,6-二乙酸酯（α-mangostin-3,6-diyl diacetate,Ⅰ）、1,5,8-三羟基-3-甲氧基-2,4-双-（3-甲基丁-2-烯）双苯吡酮（8-hydroxycudraxanthone G,Ⅱ）、1,3-二羟基-6,7-二甲氧基-2,8-双-（3-甲基丁-2-烯基）双苯吡酮（Cowaxanthone B,Ⅲ）、1,6-二羟基-3,5-二甲氧基-2-（3-甲基丁-2-烯基）双苯吡酮（Cowaxanthone A,Ⅳ）、1,5-二羟基-4-（3-甲基丁-2-烯基）-6′,6′-二甲基吡喃[2′,3′:3,2]双苯吡酮（trapezifolixanthone,Ⅴ）、1,6-二羟基-6′,6′-二甲基吡喃[2′,3′:7,8]-6″,6″-二甲基吡喃[2″,3″:3,2-]双苯吡酮（brasilixanthone B,Ⅵ）、1,3,5-三羟基-2-（3-甲基丁-2-烯）-4-（1,1-二甲基-2-烯丙基）双苯吡酮（Allanxanthone A,Ⅶ）、1,3,8-三羟基-5-甲氧基-2,4-双-（3-甲基丁-2-烯）双苯吡酮(2,4-di-(3-methylbut-2-enyl)-1,3,8-trihydroxy-5-methoxyxanthone,Ⅷ)、1,4,8-三羟基-6-甲基-3-甲氧基-9,10-蒽酮(1,4,8-trihydroxy-6-methyl-3-methoxy- 9,10-anthraquinone, Ⅸ）。 其中化合物Ⅰ、Ⅴ、Ⅵ、Ⅶ、Ⅸ为首次从藤黄属植物中分离得到,化合物Ⅱ、Ⅲ、Ⅳ、Ⅷ为首次从该植物中分离得到。     

基于量子相干效应的无芯射频识别标签的空间散射场测量

基于原子蒸汽池中铯里德伯原子的电磁感应透明光谱在微波场作用下的Aulter-Towns效应,测量了无芯射频识别标签线形散射单元的近场散射微波电场二维空间分布,空间分辨率可达到亚微波波长.实现了射频电场极化方向与线形散射体标签夹角的有效分辨.电磁仿真软件的仿真结果与实验测量符合得很好.本研究提供了一种测量微波电场近场测量的新方法,对无芯射频识别标签的散射单元设计和标定以及电子电路的电磁辐射测量具有重要的意义.     

Influence of atmosphere on lunar rover performance analysis based on soil parameter identification

This paper outlines an analysis of the traveling performance of a lunar rover. The analysis is in the form of numerical simulations and it uses soil properties, identified in vacuum, and mechanics of wheel-based travel. The wheel-to-ground contact model and soil parameters are determined first so they could be used in the numerical simulation. A soil test device is introduced and the soil parameters are identified from plate-pressing and shear tests. Finally, numerical simulations are conducted using the parameters identified and their results are discussed along with those of the traveling tests conducted in vacuum. The soil tests indicated that the wheel sinkage into the ground can increase in vacuum and that the shear stress acting beneath the wheel in vacuum is almost the same as that in the atmosphere. Because of these trends, the simulations and traveling tests showed that the traveling performance of the wheel can decrease in vacuum. Although it has been widely considered that the vacuum environments enhance the traveling performance of the wheel, this study confirmed that it is not always the case.     

Experiment-based identification of time delays in linear systems

This paper presents an identification approach to time delays in single-degree-of-freedom (SDOF) and multiple-degree-of-freedom (MDOF) systems. In an SDOF system, the impedance function of the delayed system is expressed by the system parameters, the feedback gain, and the time delay. The time delay can be treated as the "fre-quency"of the difference between the impedance function of the delayed system and that of the corresponding uncon-trolled system. Thus, it can be identified from the Fourier transform of the difference between the two impedance func-tions. In an MDOF system, the pseudo-impedance functions are defined. The relationships between the time delay and the pseudo-impedance functions of the delayed system and uncontrolled system are deduced. Similarly, the time delay can be identified from the Fourier transform of the difference between the two pseudo-impedance functions. The results of numerical examples and experimental tests show that the identification approach to keeps a relatively high accuracy.     

Directional wave separation in tubular acoustic systems – The development and evaluation of two industrially applicable techniques

An acoustic device is used to evaluate internal features and defects within tubes by determination of the acoustic impulse response. This paper concerns methods of separating the total pressure wave measured in the device into its forward and backward travelling components, which facilitates computation of the acoustic impulse response. The device comprises a tube that has a speaker at one end and is axially instrumented with microphones. Unlike similar works, the methods presented in this paper were designed to be applied in an industrial context, they allow simple calibration and implementation using readily transportable equipment. Two wave separation algorithms are presented; the first is a known method that has been improved to provide simplified calibration and the second is a computationally inexpensive technique that has been adapted to improve its operational bandwidth. The techniques are critically evaluated using a custom built test rig, designed to simulate realistic tube features and defects such as constrictions, holes and corrosion. It is demonstrated that, although inter-microphone attenuation is not accounted for in the second algorithm, both algorithms function well and give similar results. It is concluded that the added sophistication of the first method means that it is less affected by low frequency interference and is capable of yielding more accurate results. However, in practical use as an evaluation tool, the benefits of including inter-microphone attenuation are outweighed by the additional calibration and computational requirements. Finally the output of the wave separation techniques is validated by showing agreement between experimental impulse response measurements and those obtained from a theoretically derived acoustic tube simulator.     

基于三角形周长的暗星全天球自主快速识别

随着星敏感器极限探测星等能力的提高,导航星暗星数目及识别特征库急剧增加,造成星图识别耗时长,误匹配率高。通过介绍传统的三角形星图识别算法原理及不足,结合主星识别算法思想,以主星对星角距和周长为识别特征,提出了一种基于三角形周长的暗星全天球自主快速识别算法。由于9.0Mv全天球导航特征库的构建过于繁琐,为了提高运算速度,采用NVIDIA图像处理器(GPU)并行计算架构,通过CUDA计算比CPU获得了20倍以上的加速。对特征库按周长构造了散列函数,分段存储成若干个子块。识别过程中,对观测三角形周长采用哈希查找法实现子块的快速定位,星角距的识别只在相应的子块内进行,提高了识别速度,增加了识别成功率。用实拍星图分别对基于星角距和周长特征的识别算法进行了验证,实验表明,两种算法均能实现9Mv星的识别,平均识别时间分别为37.7123 s和2.0422 s,后者具有明显的优势,能够大大提高星敏感器的数据更新率。     

基于荷载形函数的大跨桥梁结构移动荷载识别

大跨桥梁结构中的移动荷载识别是结构健康监测的重要组成部分之一,其作为动力学中的反问题,存在唯一性及稳定性等病态问题。本文首先推导出移动荷载作用下结构响应的卷积形式的离散公式,然后利用有限元理论中的形函数拟合移动荷载,推导出基于荷载形函数的移动荷载识别表达式。将移动荷载的识别转化为荷载形函数拟合系数的识别,降低了需要识别的未知量,减小了逆运算的计算量,消除或减弱逆问题病态性,并提高了计算效率。利用某大跨刚构-连续预应力混凝土桥梁修正后的有限元模型进行数值仿真,考虑路面粗糙度,由模态叠加法计算移动荷载作用下的响应;然后采用荷载形函数方法识别移动荷载,证明该方法在5%以下的噪声时能快速并精确识别复杂桥梁结构的移动荷载。     

清代工笔云龙水波纹绘画颜料及技法研究

利用超景深三维视频显微镜、激光显微共聚焦拉曼光谱仪、能量色散型X射线荧光分析显微镜,对一幅清代工笔画中云龙纹、水波纹所用颜料及技法进行研究。实验结果表明,画作中人物衣服首先以人工合成颜料巴黎绿（Paris green,Cu(CH₃COO)₂·3Cu(AsO₂)₂）整体填色,再用铁红（Hematite,α-Fe₂O₃）描绘出云龙纹、水波纹,绿色、红色颜料共同呈现纹饰内区的暗黄色,此后再以Cu-Zn-Pb合金黄铜粉末勾描出“金边”。此外在画作中还发现了人工合成的群青（Ultramarine,(Na, Ca)_7-8(Al, Si)₁₂(O, S)₂₄[SO₄, Cl₂(OH)₂]）,结合巴黎绿、群青合成成功的年份,确定了画作完成的时间上限。     

1945年银行票据样品印刷颜料无损鉴定

利用超景深三维视频显微镜、激光显微共聚焦拉曼光谱仪、扫描电镜-能谱仪等,对一张1945年银行票据样品的印刷颜料进行测试分析,结果显示该票据印刷使用了颜料红146和颜料红53∶1等有机颜料,以及朱砂、碳黑、普鲁士蓝、副雄黄和χ构型雄黄等无机颜料,并推测棕黑色手写字迹由蓝黑墨水老化褪色形成。票据中各处色块多为单一呈色,有两处印章由朱砂与不同晶型的雄黄共同呈色,并且首次发现χ构型雄黄和副雄黄作为印刷颜料使用。研究表明,上述三项技术的联用可以成功地对纸质品上的有机及无机颜料进行无损鉴定,在纸质文物研究中具有广阔的应用前景。     

太赫兹光谱技术在中药大黄炮制品检测中的应用研究

针对中药炮制前后成分变化会影响中药用药疗效的问题,采用四种大黄炮制品为研究对象,利用太赫兹时域光谱系统和化学计量学处理方法获得了中药大黄光谱数据,按照中药大黄炮制品的种类对光谱数据进行了区分。同时,薄层色谱法研究显示大黄在不同炮制方法处理后,其炮制品中基础物质蒽醌和鞣质类化合物含量发生变化,而该实验获得的这四种大黄炮制品太赫兹光谱数据之间的关联性与上述变化规律相吻合。这就说明太赫兹光谱技术对中药炮制品的物质成分是敏感的,此方法可以为中药炮制过程中物质结构变化的研究提供重要参考。