Preservation of DNA in ancient Egyptian mummies

The presence of DNA has been demonstrated in the cell nuclei of an ancient Egyptian mummy fragment. When extracted, this DNA proved to be degraded to a considerable extent and chemically modified. However, the preservation of nucleic acids in this specimen suggests that applying recombinant DNA techniques to the study of ancient mummified tissues might prove to be a fruitful future area of research.     

红外光谱在传统年画红蓝色料分析中的应用研究

年画是中国特有的民间艺术形式。本研究介绍了传统年画印制所用红蓝色料的发展历史,选取15种中国古代与近现代常用红蓝色料进行红外光谱分析,并归纳总结了标准样品的化学结构与红外谱图特征。在此基础上,利用衰减全反射傅里叶变换红外光谱仪对三幅清末民初时期的传统年画开展无损检测。结果显示三幅年画的红蓝色料均为合成颜料或染料,包括酸性大红G、酸性墨水蓝G、普鲁士蓝等。本研究扩展了红外光谱在书画文物分析检测中的应用范围,为传统年画色料的无损鉴定提供科学依据。     

领导干部问责制刍议

领导干部问责制是问责制的中心环节和切入点。近年来领导干部问责在实践和制度建设上均取得了进展,但问责主体、问责范围、客体界定、问责程序方面仍有完善的空间。为此,需进行相应的制度建设,以促进领导干部问责制适应现实的需要,并为中国特色问责制度的确立奠定基础。     

弦歌台大成殿文物建筑彩绘颜料成分分析

弦歌台又被称为绝粮祠，整体布局以中轴线为中心呈现东西对称，现存建筑的规制为三进院落，从南向北依次为正门、戟门、大成殿、弦歌书院。大成殿作为弦歌台最核心的建筑，外观气势宏伟，彩绘精美绝伦，是我国东部地区规格较高的孔庙建筑之一。弦歌台大成殿在自然环境和人为因素的长期影响下，彩绘表面出现了褪色、龟裂、颜料脱落等多种病害，彩绘修复工作已成为当前文物保护亟待解决的棘手问题。本工作对彩绘样本的层位和形制进行详细分析，从剖面和表面等多角度进行全面研究，发现大部分彩绘样本由内向外的结构依次为基底层、地仗层、颜料层，蓝色彩绘样本所使用的地仗层为传统的单披灰工艺，与之不同的是红色彩绘样本为无地仗彩绘，红色颜料层直接绘制于基底层上，推测这可能与时代的发展及工艺的变化有关。为了更好地服务文物进行科学保护，需要了解大成殿彩绘颜料成分及制作工艺等。采用超景深微观分析、扫描电镜及能谱仪分析、显微拉曼光谱分析等现代技术及方法，对彩绘颜料样本进行了层位结构、微观及成分检测分析。结果表明，在制作工艺上，大成殿彩绘颜料层剖面多为两层以上叠加，是明显的重层彩绘，说明历史上至少经历过两次以上重绘。同时发现大成殿彩绘颜料层既有重...     

A PROCEDURE FOR ESTIMATING INPUT ENERGY SPECTRA FOR SEISMIC DESIGN

In this paper, the damage potential of an earthquake ground motion is evaluated in terms of the total power of the acceleration of the ground motion. By assuming an appropriate spectral shape for the input energy spectrum, and using the well-known Parseval theorem for evaluating the total power of a random signal, the peak amplification factor for the equivalent input energy velocity spectrum can be determined. It is shown that the peak amplification factor for the input energy spectrum depends on the peak-ground-acceleration to peak-ground-velocity ratio and duration of the strong motion phase of the ground motion. Values for the equivalent input energy velocity amplification factor vary from about 2 to 10 for most of the recorded ground motions used in this study. Although a considerable scatter of data is observed in this study, the peak amplification factor predicted by the Fourier amplitude spectrum of the ground acceleration provides a fairly good estimate of the mean value of the peak input energy compared to that determined from inelastic dynamic time history analyses, particularly for systems with high damping and low lateral strength. The peak amplification factor derived in this paper provides a more consistent approach for estimation of seismic demand when compared to an earlier empirical expression used for the formulation of duration-dependent inelastic seismic design spectra, even though only a slight difference in the required lateral strength results from the use of the new formula.     

Mine blast vibration response spectrum for structural vulnerability assessment: case study of heritage masonry buildings

Ground-borne vibrations induced by mine blasting are typically of low amplitudes, which are not considered a major concern for modern engineered structures. However, historic structures are often considered more vulnerable due to inadequate knowledge regarding the state of construction materials and structural response. Specifically, the construction materials used might be fragile or have deteriorated to a stage that could be vulnerable to such vibrations. Simplistic rule based on peak ground motion parameter has been adopted worldwide for safety assessment, while the frequency characteristics of vibrations are not taken into account. Further, there is very limited study on response of heritage structures to near-field blasting. This article presents a practical structural vulnerability assessment method for mine blast-induced vibrations. In particular, a design response spectrum model is proposed based on close range measurements of nearby mine blasting, which is compared with an existing design spectrum model for far-field mine blasts and a typical design spectrum model for earthquake actions. The method is illustrated through a case study of heritage masonry buildings in Australia. The unique blast data presented and the generalized methodology would be useful to both structural engineers and blast engineers in considering potential effects of blasting on heritage structures.     

新疆小河墓葬出土毛纤维老化状况的研究

利用光学显微镜、扫描电镜对新疆小河墓葬出土的毛纺织品进行形貌观察,并采用红外显微镜对样品进行测试,对出土自不同地层墓葬的样品归类分析讨论。本研究的目的是补充文物数据库;初步讨论了小河墓葬出土毛制品的保存状况;以小河墓地为例,讨论了墓葬位置对毛纤维老化状况的影响。结果显示:新疆小河墓葬出土毛织品的埋葬位置对毛织品的劣化状况有较大影响。劣化形式表现为:纤维横向、纵向的裂痕;红外光谱中酰胺Ⅱ带与酰胺Ⅰ带吸收峰峰高比值的变化;纤维上附着的结晶物推测为雨水或地下水带入的结晶盐。     

基于可见光谱特征提取的敦煌壁画颜料识别方法研究

为了对壁画颜料种类进行无损识别,根据不同的物质对光的吸收特性不同,决定着光谱反射率不同这一特性,提出一种基于可见光谱的颜料识别方法,并对敦煌壁画所用颜料进行了分析。提取可见光谱曲线二阶导数负数部分表征曲线峰值区域的几何轮廓,利用中值金字塔对提取结果进行三层分辨率表征以突出曲线峰值位置信息,归一化三种表征尺度并组合构建特征空间F,以欧氏距离为准则对壁画采样点与颜料库样本进行相似度判别,从而识别出壁画用颜料信息。结果表明,本研究构建的识别方法能够对壁画颜料种类进行无损识别,在壁画数字存档及修复领域具有一定的应用前景。     

Endogenous Fluorescence Analysis: Preliminary Study Revealing the Potential of this Non‐invasive Method to Study Mummified Samples

Autofluorescence analysis allows new insights on human tissue without any dye in a non‐invasive way and therefore seems well suited to study historical samples. An optical set‐up recorded emitted autofluorescence in 1/spectral and 2/lifetime domains from different samples' regions of interest. The studied samples were a mummified right hand, bog body (Tollund Man) feet and a male Caucasian hand (control sample). Spectral analysis revealed that mummified hand exhibited broad autofluorescence spectra, whereas Tollund Man's feet exhibited a weak single peak with 405‐nm excitation wavelength. Control sample spectra are weaker than that of the mummified hand but higher than the Tollund Man's feet. Lifetime measurements indicated the presence of classical endogenous fluorophores on the mummified right hand. The Tollund Man's feet exhibited two patterns of lifetime measurements: healthy zone exhibited lifetime values at four emission wavelengths but skin lesions at only two wavelengths. This first report of mummified samples' autofluorescence analysis suggests the potential of optical analysis for archeologic research. Copyright © 2017 John Wiley & Sons, Ltd.     

A PROCEDURE FOR COMBINING VERTICAL AND HORIZONTAL SEISMIC ACTION EFFECTS

The vertical component of earthquake ground motion has generally been neglected in the earthquake-resistant design of structures. This is gradually changing due to the increase in near-source records obtained recently, coupled with field observations confirming the possible destructive effect of high vertical vibrations.

In this paper, simple procedures are suggested for assessing the significance of vertical ground motion, indicating when it should be included in the determination of seismic actions on buildings. Proposals are made for the calculation of elastic and inelastic vertical periods of vibration incorporating the effects of vertical and horizontal motion amplitude and the cross-coupling between the two vibration periods. Simplified analysis may then be used to evaluate realistic vertical forces by employing the vertical period of vibration with pertinent spectra without resorting to inelastic dynamic analysis.

Finally, a procedure is suggested for combining vertical and horizontal seismic action effects which accounts for the likelihood of coincidence, or otherwise, of peak response in the two directions.