TY  - JOUR
A1  - Schmidt, Birgit Angelika
A1  - Ziemann, Martin Andreas
A1  - Pentzien, Simone
A1  - Gabsch, Toralf
A1  - Koch, Werner
A1  - Krüger, Jörg
T1  - Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road
JF  - Studies in Conservation
N2  - A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhohle). Its original painted surface is soot blackened and largely illegible. Gruwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified.
KW  - Wall paintings
KW  - Central Asia
KW  - Silk Road
KW  - Pigments
KW  - Microscopy
KW  - EDX
KW  - XRF
KW  - Raman spectroscopy
Y1  - 2016
U6  - https://doi.org/10.1179/2047058414Y.0000000152
SN  - 0039-3630
SN  - 2047-0584
VL  - 61
SP  - 113
EP  - 122
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Werner, Peter
A1  - Koch, Andreas
T1  - Push-pull allenes-conjugation, (anti)aromaticity and quantification of the push-pull character
JF  - Tetrahedron
N2  - Structures, H-1/C-13 chemical shifts, and pi electron distribution/conjugation of an experimentally available and theoretically completed set of push-pull allenes Acc(2)C=C=CDon(2) (Acc=F, CHO, CF3, C  N; Don=t-Bu, OMe, OEt, SMe, SEt, NCH2R) have been computed at the OFT level of theory. Both orthogonal linear and orthogonal bent structures have been obtained. In the latter case the push-pull character could be quantified by the quotient method. The C-13 chemical shift of the central allene carbon atom C-2 and chemical shift differences Delta delta(C-1, C-2) and Delta delta(C-2, C-3) of allene carbon atoms proved to be a quantitative alternative. TSNMRS of ring-closed push-pull allenes have been computed in addition and were employed to identify polar, carbene-like and carbone-like canonical structures of these molecules.
KW  - Push-pull allenes
KW  - Push-pull character
KW  - C-13 NMR spectroscopy
KW  - Quotient method
KW  - TSNMRS
KW  - ICSS
KW  - Aromaticity
Y1  - 2013
U6  - https://doi.org/10.1016/j.tet.2013.01.027
SN  - 0040-4020
VL  - 69
IS  - 11
SP  - 2436
EP  - 2445
PB  - Elsevier
CY  - Oxford
ER  -