TY  - JOUR
A1  - Chen, Shun-Gang
A1  - Li, Ji
A1  - Zhang, Fan
A1  - Xiao, Bo
A1  - Hu, Jia-Ming
A1  - Cui, Yin-Qiu
A1  - Hofreiter, Michael
A1  - Hou, Xin-Dong
A1  - Sheng, Gui-Lian
A1  - Lai, Xu-Long
A1  - Yuan, Jun-Xia
T1  - Different maternal lineages revealed by ancient mitochondrial genome of Camelus bactrianus from China
JF  - Mitochondrial DNA Part A
N2  - Domestic Bactrian camel (Camelus bactrianus) used to be one of the most important livestock species in Chinese history, as well as the major transport carrier on the ancient Silk Road. However, archeological studies on Chinese C. bactrianus are still limited, and molecular biology research on this species is mainly focused on modern specimens. In this study, we retrieved the complete mitochondrial genome from a C. bactrianus specimen, which was excavated from northwestern China and dated at 1290-1180 cal. Phylogenetic analyses using 18 mitochondrial genomes indicated that the C. bactrianus clade was divided into two maternal lineages. The majority of samples originating from Iran to Japan and Mongolia belong to subclade A1, while our sample together with two Mongolian individuals formed the much smaller subclade A2. Furthermore, the divergence time of these two maternal lineages was estimated as 165 Kya (95% credibility interval 117-222 Kya), this might indicate that several different evolutionary lineages were incorporated into the domestic gene pool during the initial domestication process. Bayesian skyline plot (BSP) analysis a slow increase in female effective population size of C. bactrianus from 5000 years ago, which to the beginning of domestication of C. bactrianus. The present study also revealed that there were extensive exchanges of genetic information among C. bactrianus populations in regions along the Silk Road.
KW  - Camelus bactrianus
KW  - mitochondrial genome
KW  - ancient DNA
KW  - phylogeny
KW  - maternal lineages
Y1  - 2019
U6  - https://doi.org/10.1080/24701394.2019.1659250
SN  - 2470-1394
SN  - 2470-1408
VL  - 30
IS  - 7
SP  - 786
EP  - 793
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - THES
A1  - Yin, Fan
T1  - Mathematic approaches for the calibration of the CHAMP satellite magnetic field measurements
T1  - Mathematische Ansätze für die Kalibrierung des Satelliten CHAMP Magnetfeldmessungen
N2  - CHAMP (CHAllenging Minisatellite Payload) is a German small satellite mission to study the earth's gravity field, magnetic field and upper atmosphere. Thanks to the good condition of the satellite so far, the planned 5 years mission is extended to year 2009. The satellite provides continuously a large quantity of measurement data for the purpose of Earth study. The measurements of the magnetic field are undertaken by two Fluxgate Magnetometers (vector magnetometer) and one Overhauser Magnetometer (scalar magnetometer) flown on CHAMP. In order to ensure the quality of the data during the whole mission, the calibration of the magnetometers has to be performed routinely in orbit. The scalar magnetometer serves as the magnetic reference and its readings are compared with the readings of the vector magnetometer. The readings of the vector magnetometer are corrected by the parameters that are derived from this comparison, which is called the scalar calibration. In the routine processing, these calibration parameters are updated every 15 days by means of scalar calibration. There are also magnetic effects coming from the satellite which disturb the measurements. Most of them have been characterized during tests before launch. Among them are the remanent magnetization of the spacecraft and fields generated by currents. They are all considered to be constant over the mission life. The 8 years of operation experience allow us to investigate the long-term behaviors of the magnetometers and the satellite systems. According to the investigation, it was found that for example the scale factors of the FGM show obvious long-term changes which can be described by logarithmic functions. The other parameters (offsets and angles between the three components) can be considered constant. If these continuous parameters are applied for the FGM data processing, the disagreement between the OVM and the FGM readings is limited to \pm1nT over the whole mission. This demonstrates, the magnetometers on CHAMP exhibit a very good stability. However, the daily correction of the parameter Z component offset of the FGM improves the agreement between the magnetometers markedly. The Z component offset plays a very important role for the data quality. It exhibits a linear relationship with the standard deviation of the disagreement between the OVM and the FGM readings. After Z offset correction, the errors are limited to \pm0.5nT (equivalent to a standard deviation of 0.2nT). We improved the corrections of the spacecraft field which are not taken into account in the routine processing. Such disturbance field, e.g. from the power supply system of the satellite, show some systematic errors in the FGM data and are misinterpreted in 9-parameter calibration, which brings false local time related variation of the calibration parameters. These corrections are made by applying a mathematical model to the measured currents. This non-linear model is derived from an inversion technique. If the disturbance field of the satellite body are fully corrected, the standard deviation of scalar error \triangle B remains about 0.1nT. Additionally, in order to keep the OVM readings a reliable standard, the imperfect coefficients of the torquer current correction for the OVM are redetermined by solving a minimization problem. The temporal variation of the spacecraft remanent field is investigated. It was found that the average magnetic moment of the magneto-torquers reflects well the moment of the satellite. This allows for a continuous correction of the spacecraft field. The reasons for the possible unknown systemic error are discussed in this thesis. Particularly, both temperature uncertainties and time errors have influence on the FGM data. Based on the results of this thesis the data processing of future magnetic missions can be designed in an improved way. In particular, the upcoming ESA mission Swarm can take advantage of our findings and provide all the auxiliary measurements needed for a proper recovery of the ambient magnetic field.
N2  - CHAMP (CHAllenging Minisatellite Payload) ist eine deutsche Kleinsatellitenmission für die Forschung und Anwendung in Bereich der Geowissenschaften und Atmosphärenphysik. Das Projekt wird vom GFZ geleitet. Mit seinen hochgenauen, multifunktionalen, sich ergänzenden Nutzlastelementen (Magnetometer, Akzelerometer, Sternsensor, GPS-Empfänger, Laser-Retroreflektor, Ionendriftmeter) liefert CHAMP erstmalig gleichzeitig hochgenaue Schwere- und Magnetfeldmessungen (seit Mitte 2000). Dank des bisherigen guten Zustandes des Satelliten ist die auf 5 Jahre ausgelegte Mission bis 2009 verlängert geworden. An Board befinden sich ein skalares Overhauser-Magnetometer(OVM) für Kalibrierungszwecke sowie zwei Fluxgate-Magnetometer(FGM) zur Messung des magnetischen Feldvektors. Die Messungen vom FGM werden immer verglichen mit denen vom OVM und korregiert im Fall von Widersprüche, das ist die sog. Skalar-Kalibrierung. Um eine zuverlässige Datenqualität während der 8 jährigen Mission zu garantieren, ist die Nachkalibrierung implementiert. Im Rahmen der standard mäßigen Datenverarbeitung werden die Instrumentenparameter des FGM alle 15 Tage neu bestimmt. Das Ziel der vorliegenden Arbeit ist es, eine Verbesserung der Vektormagnetfelddaten zu erzielen durch eine neue Methode der Kalibrierung, die die Eigenschaften der Sensoren und Störung vom Raumfahrzeug mit berücksichtigt. Die Erfahrung aus den zurückliegenden Jahren hat gezeigt, dass sich die Skalenfaktoren des FGM stark mit der Zeit ändern. Dieser Verlauf lässt sich gut durch eine Logarithmuskurve anpassen. Andere Parameter wie die Winkel und die Offsets scheinen stabil zu sein. Eine Ausnahme macht der Offset der Z-Komponent. Dieser bedarf einer regelmäßigen Korrektur. Während die Standardverarbeitung eine undifferenzierte Bestimmung aller 9 FGM Parameter durch nicht-lineare Inversion der skalar Daten vornimmt, beziehen wir jetzt die langzeitlichen Eigenschaften der Parameter in die Bestimmung mit ein. Eine weitere Verbesserung der CHAMP-Magnetfelddaten konnte erreicht werden durch geeignete Berücksichtigung von Störung vom Raumfahrzeug. Die verbleibenden Unsicherheiten konnten durch diese Maßnahmen auf eine Standardabweichung von 0.1nT reduziert werden.
KW  - Magnetische Feldmessungen
KW  - Magnetometer-Kalibrierung
KW  - Magnetfeld-Satellit
KW  - Magnetic field measurements
KW  - magnetometer calibration
KW  - magnetic field satellites
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-41201
ER  - 
TY  - JOUR
A1  - Lai, Huagui
A1  - Luo, Jincheng
A1  - Zwirner, Yannick
A1  - Olthof, Selina
A1  - Wieczorek, Alexander
A1  - Ye, Fangyuan
A1  - Jeangros, Quentin
A1  - Yin, Xinxing
A1  - Akhundova, Fatima
A1  - Ma, Tianshu
A1  - He, Rui
A1  - Kothandaraman, Radha K.
A1  - Chin, Xinyu
A1  - Gilshtein, Evgeniia
A1  - Muller, Andre
A1  - Wang, Changlei
A1  - Thiesbrummel, Jarla
A1  - Siol, Sebastian
A1  - Prieto, Jose Marquez
A1  - Unold, Thomas
A1  - Stolterfoht, Martin
A1  - Chen, Cong
A1  - Tiwari, Ayodhya N.
A1  - Zhao, Dewei
A1  - Fu, Fan
T1  - High-performance flexible all-Perovskite tandem solar cells with reduced V-OC-deficit in wide-bandgap subcell
JF  - Advanced energy materials
N2  - Among various types of perovskite-based tandem solar cells (TSCs), all-perovskite TSCs are of particular attractiveness for building- and vehicle-integrated photovoltaics, or space energy areas as they can be fabricated on flexible and lightweight substrates with a very high power-to-weight ratio. However, the efficiency of flexible all-perovskite tandems is lagging far behind their rigid counterparts primarily due to the challenges in developing efficient wide-bandgap (WBG) perovskite solar cells on the flexible substrates as well as their low open-circuit voltage (V-OC). Here, it is reported that the use of self-assembled monolayers as hole-selective contact effectively suppresses the interfacial recombination and allows the subsequent uniform growth of a 1.77 eV WBG perovskite with superior optoelectronic quality. In addition, a postdeposition treatment with 2-thiopheneethylammonium chloride is employed to further suppress the bulk and interfacial recombination, boosting the V-OC of the WBG top cell to 1.29 V. Based on this, the first proof-of-concept four-terminal all-perovskite flexible TSC with a power conversion efficiency of 22.6% is presented. When integrating into two-terminal flexible tandems, 23.8% flexible all-perovskite TSCs with a superior V-OC of 2.1 V is achieved, which is on par with the V-OC reported on the 28% all-perovskite tandems grown on the rigid substrate.
KW  - all-perovskite tandems
KW  - flexible tandem solar cells
KW  - perovskite
KW  - V OC-deficit
KW  - wide-bandgap
Y1  - 2022
U6  - https://doi.org/10.1002/aenm.202202438
SN  - 1614-6832
SN  - 1614-6840
VL  - 12
IS  - 45
PB  - Wiley-VCH
CY  - Weinheim
ER  -