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| 1 | New eolian red clay sequence on the western Chinese Loess Plateau linked to onset of Asian desertification about 25 Ma ago显示文摘The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese Loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese Loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese Loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene. | QIANG XiaoKe AN ZhiSheng SONG YouGui CHANG Hong SUN YouBin LIU WeiGuo AO Hong DONG JiBao FU ChaoFeng WU Feng LU FengYan CAI YanJun ZHOU WeiJian CAO JunJi XU XinWen AI Li | 2011 | Science China Earth Sciences2011，54，1： | 73 |
| 2 | Comparative analysis on dynamic behavior of two HMA railway substructures显示文摘A numerical analysis using a finite element program was performed on three structures:hot mix asphalt(HMA) reinforced trackbed(RACS-1),HMA directly supported trackbed(RACS-2),and traditional Portland Cement Concrete(PCC) slab track(SlabTrack).Although the comprehensive dynamic responses of RACS-1 were similar with SlabTrack,HMA layer can positively affect the stress distributions.In particular,the horizontal stresses indicate that the resilience of RACS-1 was improved relative to SlabTrack.In addition,HMA reinforced substructure has the capacity to recover the residual vertical deformation.The effective depth for weakening dynamic loadings is mainly from 0 to 2 m,this being especially true at 0.5 m.The results from the analysis show that HMA is a suitable material for the railway substructure to enhance resilient performance,improve the stress distribution,weaken dynamic loading,and lower the vibration,especially at the effective depth of 2 m.The HMA constructed at the top of the stone subbase layer allows the vertical modulus a smooth transition.In terms of the comprehensive dynamic behaviors,RACS-1 is better than SlabTrack,while the results for RACS-2 are inconclusive and require further research. | Mingjing FANG Yanjun QIU Jerry G. ROSE Randy C. WEST Changfa AI | 2011 | Journal of Modern Transportation2011，19，1： | 3 |
| 3 | DNA methylation affects photoperiodic tuberization in potato (Solanum tuberosum L.) by mediating the expression of genes related to the photoperiod and GA pathways显示文摘Overcoming short-day-dependent tuberization to adapt to long-day conditions is critical for the widespread geographical success of potato.The genetic pathways of photoperiodic tuberization are similar to those of photoperiodic flowering.DNA methylation plays an important role in photoperiodic flowering.However,little is known about how DNA methylation affects photoperiodic tuberization in potato.Here,we verified the effect of a DNA methylation inhibitor on photoperiodic tuberization and compared the DNA methylation levels and differentially methylated genes(DMGs)in the photoperiodic tuberization process between photoperiod-sensitive and photoperiod-insensitive genotypes,aiming to dissect the role of DNA methylation in the photoperiodic tuberization of potato.We found that a DNA methylation inhibitor could promote tuber initiation in strict short-day genotypes.Whole-genome DNA methylation sequencing showed that the photoperiod-sensitive and photoperiod-insensitive genotypes had distinct DNA methylation modes in which few differentially methylated genes were shared.Transcriptome analysis confirmed that the DNA methylation inhibitor regulated the expression of the key genes involved in the photoperiod and GA pathways to promote tuber initiation in the photoperiod-sensitive genotype.Comparison of the DNA methylation levels and transcriptome levels identified 52 candidate genes regulated by DNA methylation that were predicted to be involved in photoperiodic tuberization.Our findings provide a new perspective for understanding the relationship between photoperiod-dependent and GA-regulated tuberization.Uncovering the epigenomic signatures of these pathways will greatly enhance potato breeding for adaptation to a wide range of environments. | Yanjun Ai Shenglin Jing Zhengnan Cheng Botao Song Conghua Xie Jun Liu Jun Zhou | 2021 | Horticulture Research2021，8，1： | 1 |
| 4 | A multiple-proxy stalagmite record reveals historical deforestation in central Shandong, northern China显示文摘Evaluating anthropogenic impacts on regional vegetation changes during historical time is not only important for a better understanding of the Anthropocene but also valuable in improving the vegetation-climate models.In this study,we analyzed stable isotopes(δ^18O,δ^13C)and trace elements(Mg/Ca,Sr/Ca)of a stalagmite from Huangchao Cave in central Shandong,northern China.230Th and AMS14C dating results indicate the stalagmite deposited during 174BC and AD1810,with a hiatus between AD638 and 1102.Broad similarities of theδ^18O and trace elements in the stalagmite suggest they are reliable precipitation indexes.Theδ^13C of the stalagmite,a proxy of vegetation change,was generally consistent with local precipitation and temperature variations on a centennial-scale before the 15th century.It typically varied from–9.6‰to–6.3‰,indicating climate controlled C3 type vegetation during this period.However,a persistent and marked increasing trend in theδ^13C record was observed since the 15th century,resulting inδ^13C values from–7.7‰to–1.6‰in the next four centuries.This unprecedentedδ^13C change caused by vegetation deterioration cannot be explained by climate change but is fairly consistent with the dramatically increasing population and farmland in Shandong.We suggest that the increasing deforestation and reclamation in central Shandong began to affect vegetation in the mountain region of central Shandong since the 15th century and severely destroyed or even cleared the forest during the 16th–18th century. | Liangcheng TAN Wen LIU Tianli WANG Peng CHENG Jingjie ZANG Xiqian WANG Le MA Dong LI Jianghu LAN R.Lawrence EDWARDS Hai CHENG Hai XU Li AI Yongli GAO Yanjun CAI | 2020 | Science China Earth Sciences2020，63，10： | 1 |
| 5 | Testing and assessing the performance of a new warm mix asphalt with SMC显示文摘Warm mix asphalt(WMA)is a new technology which asphalt mix is produced and placed at normal temperature.It has advantages including low cost,environmentally friendly,haul-convenience,and so on.WMA has been widely tested and applied in the USA in the last decade,but it has just started in China.Recently,a new WMA using a new plasticmacromolecule-normal temperature additive,which was called'SMC'by the production company,was introduced as asphalt modifier.Based on discussing the strength forming process of this new WMA with SMC,a series of laboratory tests,including Marshall stability test(MST),boiling test(BT),modified immersion Marshall test(MIMT),freeze-thaw splitting test(FTST),rutting test(RT),low-temperature bending test(LTBT),and abrasion loss test(ALT),were conducted in this study to assess the performance of this WMA and the capability of applying it on low volume roads in China.SMC modified asphalt mixed under normal temperature is used in testing samples.It was found that this WMA product exhibited merits on its strength,which was about 6.7 k N bigger than the requirement of5.0 k N in the JTG F40-2004,on high-temperature stability,which is about 1100 times/mm greater than the requirement of 600e1000 times/mm in the JTG F40-2004,and on its storage stability.Based on these indicators,it is recommended that this product could be used for low volume low class roads construction.However,due to the relatively lower water resistance and low-temperature cracking resistance,this product is suggested to be applied first in the areas with warm weather and little rainfall.In order to improve the performance of this WMA with SMC,further research on this SMC asphalt modifier should be continued. | Changfa Ai Qiang Joshua Li Yanjun Qiu | 2015 | Journal of Traffic and Transportation Engineering(English Edition)2015，2，6： | 0 |
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