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喜马拉雅山谷谷底受构造驱动的岩石隆起控制 快报文章
地球科学快报,2023年第18期
作者:  王晓晨
Microsoft Word(15Kb)  |  收藏  |  浏览/下载:535/0  |  提交时间:2023/09/25
Himalayan valley-floor  tectonically driven  
Ozone Production in the Soberanes Smoke Haze: Implications for Air Quality in the San Joaquin Valley During the California Baseline Ozone Transport Study 期刊论文
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2020, 125 (11)
作者:  Langford, Andrew O.;  Alvarez, Raul J., II;  Brioude, J.;  Caputi, Dani;  Conley, Stephen A.;  Evan, S.;  Faloona, Ian C.;  Iraci, Laura T.;  Kirgis, Guillaume;  Marrero, Josette E.;  Ryoo, Ju-Mee;  Senff, Christoph J.;  Yates, Emma L.
收藏  |  浏览/下载:14/0  |  提交时间:2020/08/18
ozone  wildfire  lidar  aircraft  California  San Joaquin Valley  
Identifying Characteristic and Anomalous Mantle From the Complex Relationship Between Abyssal Hill Roughness and Spreading Rates 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2020, 47 (11)
作者:  Goff, John A.
收藏  |  浏览/下载:6/0  |  提交时间:2020/05/20
mid-ocean ridges  axial high  axial valley  faulting  
The Photoelectron-Driven Upper Hybrid Instability as the Cause of 150-km Echoes 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2020, 47 (8)
作者:  Longley, William J.;  Oppenheim, Meers M.;  Pedatella, Nick M.;  Dimant, Yakov S.
收藏  |  浏览/下载:4/0  |  提交时间:2020/07/02
150 km echoes  radar  valley region  ionosphere  plasma  instability  
Mott and generalized Wigner crystal states in WSe2/WS2 moire superlattices 期刊论文
NATURE, 2020, 579 (7799) : 359-+
作者:  Yuan, Jie;  Chang, Si-Yuan;  Yin, Shi-Gang;  Liu, Zhi-Yang;  Cheng, Xiu;  Liu, Xi-Juan;  Jiang, Qiang;  Gao, Ge;  Lin, De-Ying;  Kang, Xin-Lei;  Ye, Shi-Wei;  Chen, Zheng;  Yin, Jiang-An;  Hao, Pei;  Jiang, Lubin;  Cai, Shi-Qing
收藏  |  浏览/下载:50/0  |  提交时间:2020/07/03

Strongly correlated insulating Mott and generalized Wigner phases are detected in WSe2/WS2 moire superlattices, and their electrical properties and excited spin states are studied using an optical technique.


Moire superlattices can be used to engineer strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states observed in magic-angle twisted-bilayer graphene and ABC trilayer graphene/boron nitride moire superlattices(1-4). Transition metal dichalcogenide moire heterostructures provide another model system for the study of correlated quantum phenomena(5) because of their strong light-matter interactions and large spin-orbit coupling. However, experimental observation of correlated insulating states in this system is challenging with traditional transport techniques. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moire superlattices. We use a sensitive optical detection technique and reveal a Mott insulator state at one hole per superlattice site and surprising insulating phases at 1/3 and 2/3 filling of the superlattice, which we assign to generalized Wigner crystallization on the underlying lattice(6-11). Furthermore, the spin-valley optical selection rules(12-14) of transition metal dichalcogenide heterostructures allow us to optically create and investigate low-energy excited spin states in the Mott insulator. We measure a very long spin relaxation lifetime of many microseconds in the Mott insulating state, orders of magnitude longer than that of charge excitations. Our studies highlight the value of using moire superlattices beyond graphene to explore correlated physics.


  
Electrically pumped topological laser with valley edge modes 期刊论文
NATURE, 2020, 578 (7794) : 246-+
作者:  Erickson, Peter;  van Asselt, Harro;  Koplow, Doug;  Lazarus, Michael;  Newell, Peter;  Oreskes, Naomi;  Supran, Geoffrey
收藏  |  浏览/下载:46/0  |  提交时间:2020/07/03

Quantum cascade lasers are compact, electrically pumped light sources in the technologically important mid-infrared and terahertz region of the electromagnetic spectrum(1,2). Recently, the concept of topology(3) has been expanded from condensed matter physics into photonics(4), giving rise to a new type of lasing(5-8) using topologically protected photonic modes that can efficiently bypass corners and defects(4). Previous demonstrations of topological lasers have required an external laser source for optical pumping and have operated in the conventional optical frequency regime(5-8). Here we demonstrate an electrically pumped terahertz quantum cascade laser based on topologically protected valley edge states(9-11). Unlike topological lasers that rely on large-scale features to impart topological protection, our compact design makes use of the valley degree of freedom in photonic crystals(10,11), analogous to two-dimensional gapped valleytronic materials(12). Lasing with regularly spaced emission peaks occurs in a sharp-cornered triangular cavity, even if perturbations are introduced into the underlying structure, owing to the existence of topologically protected valley edge states that circulate around the cavity without experiencing localization. We probe the properties of the topological lasing modes by adding different outcouplers to the topological cavity. The laser based on valley edge states may open routes to the practical use of topological protection in electrically driven laser sources.


  
Channelization cascade in landscape evolution 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (3) : 1375-1382
作者:  Bonetti, Sara;  Hooshyar, Milad;  Camporeale, Carlo;  Porporato, Amilcare
收藏  |  浏览/下载:7/0  |  提交时间:2020/05/13
ridge and valley patterns  landscape evolution model  detachment limited  river networks  drainage area  
Climate prediction of summer extreme precipitation frequency in the Yangtze River valley based on sea surface temperature in the southern Indian Ocean and ice concentration in the Beaufort Sea 期刊论文
INTERNATIONAL JOURNAL OF CLIMATOLOGY, 2019
作者:  Tian, Baoqiang;  Fan, Ke
收藏  |  浏览/下载:10/0  |  提交时间:2020/02/17
Beaufort Sea  climate prediction  extreme heavy precipitation  sea-ice concentration  southern Indian Ocean  SST  Yangtze River valley  
Last appearance of Homo erectus at Ngandong, Java, 117,000-108,000 years ago 期刊论文
NATURE, 2020, 577 (7790) : 381-+
作者:  Haldane, Andy
收藏  |  浏览/下载:30/0  |  提交时间:2020/04/16

Homo erectus is the founding early hominin species of Island Southeast Asia, and reached Java (Indonesia) more than 1.5 million years ago(1,2). Twelve H. erectus calvaria (skull caps) and two tibiae (lower leg bones) were discovered from a bone bed located about 20 m above the Solo River at Ngandong (Central Java) between 1931 and 1933(3,4), and are of the youngest, most-advanced form of H. erectus(5-8). Despite the importance of the Ngandong fossils, the relationship between the fossils, terrace fill and ages have been heavily debated(9-14). Here, to resolve the age of the Ngandong evidence, we use Bayesian modelling of 52 radiometric age estimates to establish-to our knowledg-the first robust chronology at regional, valley and local scales. We used uranium-series dating of speleothems to constrain regional landscape evolution  luminescence, (40)argon/(39)argon (Ar-40/Ar-39) and uranium-series dating to constrain the sequence of terrace evolution  and applied uranium-series and uranium series-electron-spin resonance (US-ESR) dating to non-human fossils to directly date our re-excavation of Ngandong(5,15). We show that at least by 500 thousand years ago (ka) the Solo River was diverted into the Kendeng Hills, and that it formed the Solo terrace sequence between 316 and 31 ka and the Ngandong terrace between about 140 and 92 ka. Non-human fossils recovered during the re-excavation of Ngandong date to between 109 and 106 ka (uranium-series minimum)(16) and 134 and 118 ka (US-ESR), with modelled ages of 117 to 108 thousand years (kyr) for the H. erectus bone bed, which accumulated during flood conditions(3,17). These results negate the extreme ages that have been proposed for the site and solidify Ngandong as the last known occurrence of this long-lived species.


  
Climate change impacts on groundwater storage in the Central Valley, California 期刊论文
CLIMATIC CHANGE, 2019, 157 (3-4) : 387-406
作者:  Alam, Sarfaraz;  Gebremichael, Mekonnen;  Li, Ruopu;  Dozier, Jeff;  Lettenmaier, Dennis P.
收藏  |  浏览/下载:9/0  |  提交时间:2020/02/17
Groundwater  Central Valley  Climate change  Integrated modeling