Assessment of bog-body tissue preservation by pyrolysis-gas chromatography/mass spectrometry

Flash pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) was used to assess the quality and mechanism of protein preservation in the tissue of Iron Age bog bodies from Lindow, UK, and south-eastern Drenthe, The Netherlands. Abundant pyrolysis products of the fresh skin tissue, including 2,5-diketopiperazines of Pro-Gly, Pro-Ala, Pro-Val, Pro-Pro and Hyp, were readily assigned to specific amino acid or dipeptide moieties. Comparison of the pyrolysates of the bog-body tissues with that of modern samples revealed qualitative similarities suggesting good preservation of the collagen and non-collagenous proteins in the ancient tissues. Examination of the pyrolysates of samples of fresh calf skin, which had been treated with various vegetable tanning agents, clearly revealed markers of non-hydrolysable tannins including 1,2-benzenediol, 1,3-benzenediol and 1,2,3-benzenetriol, although chromatographic quality inevitably diminished with increasing functionalization of the compounds. Such markers were not detected in the pyrolysates of the bog-body tissues. Instead 4-isopropenylphenol, a characteristic pyrolysis product of Sphagnum moss, was detected in both solvent-extracted and base-treated samples of tissue. The presence of 4-isopropenylphenol in the pyrolysates of the bog-body tissues provides evidence that their preservation involves reactions of amino acids with sphagnum acid, and possibly other agents derived from the peat. The study constitutes the first chemical characterization of the pyrolysis products of modern and ancient collagen.     

CVT中阻尼器的研究

阐述了电容式电压互感器的各种阻尼器的优缺点,并对速饱和阻尼器设计进行了详述,提出了CVT设计速饱和阻尼器应注意的事项。     

XYZ-125稀油站系统管径优化可行性分析

采油厂为C5101A/B往复式压缩机提供润滑的XYZ-125型稀油站,按照传统设计方法计算与设计,管道通径选择过大,造成设备体积庞大,生产制造成本过高.针对此情况,对XYZ-125稀油站管道系统进行分析与计算,在传统设计的基础上,采用现代计算机模拟优化的方法,通过建立XYZ-125稀油站管道中压力峰值区域三维模型,导入ANSYS软件进行模拟分析后,得出稀油站工作时液流的流动状态参数,为系统优化可行性分析提供直接数据支持和理论依据.优化后的系统体积减小,降低了整个设备的生产制造成本.     

Editorial

On the start occasion of the New Year, 2012, we would like to extend our sincere appreciations and compliments to all readers, authors, reviewers, the members of the editorial board of Optoelectronics Letters, colleagues and friends, and wish you peace, health and hap- piness throughout 2012. The New Year is a time of new beginnings and new hopes for the     

LDA端泵浦短腔Cr^4＋：YAG被动调Q Nd：YAG激光器

采用峰值功率600W的准连续（QCW）激光二极管阵列（LDA）端泵浦Nd:YAG晶体，其耦合装置为自制的微柱透镜阵列和透镜导管，使用Cr^4 :YAG可饱和吸收晶体作为Q开关，并选取长度较短的Nd:YAG晶体，从而使激光腔的长度缩短到11mm，实验研究了在较短的腔长条件下调Q输出多脉波形的时间、空间分布，采用平－平腔结构时，每次泵浦脉冲获得单脉冲输出，脉冲宽度＜4ns，能量4．5mJ。     

高补偿硅的光敏感特性

对电阻率为5 ·cm的p型单晶硅,在高温条件下采用扩散金属锰的方法,得到高补偿硅。并在室温(25℃)和液氮温度(196℃)下,测试了这种高补偿硅材料对光强的敏感性。测试结果表明:这种材料是一种光敏感材料,其敏感性受外加的电压、样品的温度及补偿后样品的电阻率影响。     

可靠性试验自动测试系统的设计

介绍基于GPIB技术的可靠性试验自动测试系统的设计,详细阐述了该系统的硬件组成和软件编程。该自动测试系统不仅具有很高的测试效率和测试精度,而且操作简单,具有良好的扩展性,适用于通用雷达装备板级可靠性试验的评估与验证。经过长时间的试验测试以及获得的大量数据表明,该可靠性试验测试系统运行稳定可靠,数据采集、存储、分析方便,满足通用雷达可靠性试验的测试要求。