Xingjiang University

Urunchi, China

Xingjiang University

Urunchi, China
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Ran M.,Xingjiang University | Feng Z.,Xinjiang Institute of Ecology and Geography
Organic Geochemistry | Year: 2014

We present a high resolution record of δ13Corg variation from two loess sequences in central Kazakhstan. The variation shows that the vegetation was persistently dominated by C3 plants over the past ca. 46,000yr. The δ13Corg signature was most likely an indicator of moisture and the moisture variation in central Kazakhstan was associated with the precipitation in Western Europe. The δ13Corg indicated that moisture variation exhibited five stages: decreasing during stage 1 (ca. 46,000-ca. 31,500yr BP), increasing during stage 2 (ca. 31,500-ca. 25,500yr BP), again decreasing during stage 3 (ca. 25,500-ca. 19,000yr BP), fluctuating along a constant line during stage 4 (ca. 19,000-ca. 5000yr BP) and increasing during stage 5 (last ca. 5000yr). Our comparison demonstrated a general similarity between the δ13Corg-indicated moisture variation in central Kazakhstan and the reconstructed precipitation variation in Western Europe. The similarity implies that the moisture of the past ca. 46,000yr in central Kazakhstan has been controlled or modulated by westerlies that brought water vapor from the North Atlantic not only to Western Europe but also to central Kazakhstan. © 2014 Elsevier Ltd.


Ran M.,Xingjiang University | Feng Z.,Xinjiang Institute of Ecology and Geography
Quaternary International | Year: 2013

Based on the review of 33 Holocene moisture reconstructions that passed quality scrutiny, temporal and spatial patterns of regional moisture variations are delineated. The regionally-averaged moisture index from Xinjiang demonstrates that the moisture index has been persistently climbing since ~10ka cal BP and that the period between ~4 and ~0ka cal BP is the Holocene Moisture Optimum. Comparison of the moisture index of Xinjiang region with the winter climate of northern Europe leads us to propose that the Holocene moisture variations in Xinjiang region have been controlled by the winter temperature variations in the North Atlantic region. The regionally-averaged moisture index from the Tibetan Plateau shows that the moisture has been persistently declining since ~11ka cal BP and that the period between ~11.5 and 7.5ka cal BP was the Holocene Moisture Optimum. The parallel trends between the moisture level in the Tibetan Plateau and the Indian summer monsoon strength retrieved from the Arabian Sea suggest that the Tibetan Plateau has been under influence of the Indian summer monsoon throughout the Holocene. The regionally-averaged moisture index curves from Northern China and Southern China are the delayed reflections of the East Asian summer monsoon strength to the solar radiation. That is, the peak insolation was responded by the Holocene "Oceanic Thermal Optimum" with significant time lags and the "Oceanic Thermal Optimum" was then responded by the "Holocene Moisture Optimum" in southern China and northern China also with some time lags. The differences in the moisture-index curve shapes and in the durations of the "Holocene Moisture Optimum" between northern China and southern China suggest that the strength of the East Asian summer monsoon had gradually transgressed northward in the early Holocene and gradually regressed southward in the late Holocene. © 2013 Elsevier Ltd and INQUA.


Wang W.,Inner Mongolia University | Feng Z.,Xinjiang Institute of Ecology and Geography | Ran M.,Xingjiang University | Zhang C.,Lanzhou University
Quaternary International | Year: 2013

This research focuses on the reconstructions of the lake hydrologic variations and the basin-wide vegetation changes over past ~13,870 years based on pollen data of 195 samples and the lithologic variations obtained from Lake Aibi in the western part of Xinjiang area. Our results showed that lake or swamp environment did not come into existence until ~13,870cal.BP and swamp or wetland environment dominated the depression of the basin between ~13,870 and ~7430cal.BP under ameliorated basin-wide moisture conditions. The following period between ~7430 and ~3620cal.BP witnessed lake transgression in the depression and vegetation amelioration within the basin. The moisture conditions were continuously ameliorated from ~3620cal.BP onward, leading to further lake transgression and further basin-wide vegetation amelioration. A dry interval from ~1400 to ~1150cal.BP interrupted the late Holocene wet epoch of the past ~3600 years.Our synthesized (regionally-averaged) moisture index of Xinjiang area indicates that a gradual wetting climate dominated the mid- to late-Holocene in Xinjiang area. This wetting trend in Xinjiang area is hypothesized to have been associated with the winter warming and winter wetting trends in northern Europe. The gradual increase of winter insolation in mid- to late-Holocene might have enhanced evaporation in the North Atlantic Ocean and injected more moisture to the westerlies system, therefore bringing more precipitation to the downwind area including Xinjiang. © 2013 Elsevier Ltd and INQUA.


Wang Z.,Laboratory of Oasis Ecology of Xinjiang | Wang Z.,Xingjiang University | Wang Z.,Xinjiang University | Chang S.-L.,Laboratory of Oasis Ecology of Xinjiang | And 11 more authors.
Chinese Journal of Applied Ecology | Year: 2010

Based on the fractional vegetation cover (FVC) data of 1982 -2000 NOAA/AVHRR (National Oceanic and Atmospheric Administration / the Advanced Very High Resolution Radiome ter) images, the whole arid area of Northwest China was divided into three sub-areas, and then, the vegetation cover in each sub-area was classified by altitude. Furthermore, the Markov process of vegetation cover change was analyzed and tested through calculating the limit probability of any two years and the continuous and interval mean transition matrixes of vegetation cover change with 8 km x 8 km spatial resolution. By this method, the Markov process of vegetation cover change and its indicative significance were approached. The results showed that the vegetation cover change in the study area was controlled by some random processes and affected by long-term stable driving fac tors, and the transitional change of vegetation cover was a multiple Markov process. Therefore, only using two term image data, no matter they were successive or intervallic, Markov process could not accurately estimate the trend of vegetation cover change. As for the arid area of Northwest China, more than 10 years successive data could basically reflect all the factors affecting regional vegetation cover change, and using long term average transition matrix data could reliably simulate and predict the vegetation cover change. Vegetation cover change was a long term dynamic balance. Once the balance was broken down, it should be a long time process to establish a new balance.


Yuan Y.P.,Xingjiang University | Sun W.L.,Xingjiang University | Huang S.,Xingjiang University | Ni Y.Y.,Xingjiang University
Advanced Materials Research | Year: 2011

The Qing-ling machine is the cleaning part of Comb-type cotton picker. Its working performance directly affects the complete machine efficiency. In order to improve popularizing rate of Comb-type cotton picker, combining with the cotton varieties, the plant characteristics, climatic conditions and the harvests requirements in Xinjiang, the reasonable structures, transmission system and design parameters of Qing-ling machine are put forward. Virtual prototypes of key components are set up under Pro/E. the kinetic simulation data are obtained by using ADAMS. Simulation results prove design correctness and provide relevant data for further research. © (2011) Trans Tech Publications.


Wang D.-G.,Xingjiang University | Wang X.-Y.,Xingjiang University | Zhou D.-D.,Xingjiang University | Mu L.-S.,Xingjiang University | And 2 more authors.
Chinese Physics Letters | Year: 2010

By using a pump-probe technique, the nascent rotational and vibrational state distributions of CsH are obtained in the Cs(62D,72D) plus H2 reaction. The nascent CsH molecules are found to populate the lowest two vibrational (ν″ 0 and 1) levels of the ground electronic state. By comparing the spectral intensities of the CsH action spectra with those of pertinent Cs atomic fluorescence excitation spectra, the relative reactivity with H2 is in an order of 62D3/2 > 62D5/2 > 72D3/2 > 7 2D5/2. The rotational temperatures are found to be slightly below the cell temperature. The relative fractions (fV, fR, fT) of average energy disposal are derived as (0.2,0.12,0.68), (0.2,0.12,0.68), (0.07,0.04,0.89) and (0.07,0.04,0.89) for the 62D3/2, 62D5/2, 72D 3/2 and 72D5/2, respectively. The major available energy is released as translation. These results support that the reaction mechanism of Cs(62D,72D) plus H2 is primarily a collinear abstraction and not an insertion. © 2010 Chinese Physical Society and IOP Publishing Ltd.

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