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Effects of Groundwater Pumping on Ground Surface Temperature: A Regional Modeling Study in the North China Plain 期刊论文
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2020, 125 (9)
作者:  Yang, Chen;  Li, Hong-Yi;  Fang, Yilin;  Cui, Chixiao;  Wang, Tianye;  Zheng, Chunmiao;  Leung, L. Ruby;  Maxwell, Reed M.;  Zhang, You-Kuan;  Yang, Xiaofan
收藏  |  浏览/下载:27/0  |  提交时间:2020/07/02
the North China Plain  groundwater pumping  ground surface temperature  integrated hydrologic modeling  ParFlow  CLM  
Simulation of Hubbard model physics in WSe2/WS2 moire superlattices 期刊论文
NATURE, 2020, 579 (7799) : 353-+
作者:  Stein, Reed M.;  Kang, Hye Jin;  McCorvy, John D.;  Glatfelter, Grant C.;  Jones, Anthony J.;  Che, Tao;  Slocum, Samuel;  Huang, Xi-Ping;  Savych, Olena;  Moroz, Yurii S.;  Stauch, Benjamin;  Johansson, Linda C.;  Cherezov, Vadim;  Kenakin, Terry;  Irwin, John J.;  Shoichet, Brian K.;  Roth, Bryan L.;  Dubocovich, Margarita L.
收藏  |  浏览/下载:27/0  |  提交时间:2020/07/03

Study of WSe2/WS2 moire superlattices reveals the phase diagram of the triangular-lattice Hubbard model, including a Mott insulating state at half-filling and a possible magnetic quantum phase transition near 0.6 filling.


The Hubbard model, formulated by physicist John Hubbard in the 1960s(1), is a simple theoretical model of interacting quantum particles in a lattice. The model is thought to capture the essential physics of high-temperature superconductors, magnetic insulators and other complex quantum many-body ground states(2,3). Although the Hubbard model provides a greatly simplified representation of most real materials, it is nevertheless difficult to solve accurately except in the one-dimensional case(2,3). Therefore, the physical realization of the Hubbard model in two or three dimensions, which can act as an analogue quantum simulator (that is, it can mimic the model and simulate its phase diagram and dynamics(4,5)), has a vital role in solving the strong-correlation puzzle, namely, revealing the physics of a large number of strongly interacting quantum particles. Here we obtain the phase diagram of the two-dimensional triangular-lattice Hubbard model by studying angle-aligned WSe2/WS2 bilayers, which form moire superlattices(6) because of the difference between the lattice constants of the two materials. We probe the charge and magnetic properties of the system by measuring the dependence of its optical response on an out-of-plane magnetic field and on the gate-tuned carrier density. At half-filling of the first hole moire superlattice band, we observe a Mott insulating state with antiferromagnetic Curie-Weiss behaviour, as expected for a Hubbard model in the strong-interaction regime(2,3,7-9). Above half-filling, our experiment suggests a possible quantum phase transition from an antiferromagnetic to a weak ferromagnetic state at filling factors near 0.6. Our results establish a new solid-state platform based on moire superlattices that can be used to simulate problems in strong-correlation physics that are described by triangular-lattice Hubbard models.


  
Quantum crystal structure in the 250-kelvin superconducting lanthanum hydride 期刊论文
NATURE, 2020, 578 (7793) : 66-+
作者:  Gate, David;  Saligrama, Naresha;  Leventhal, Olivia;  Yang, Andrew C.;  Unger, Michael S.;  Middeldorp, Jinte;  Chen, Kelly;  Lehallier, Benoit;  Channappa, Divya;  De Los Santos, Mark B.;  McBride, Alisha;  Pluvinage, John;  Elahi, Fanny;  Tam, Grace Kyin-Ye;  Kim, Yongha;  Greicius, Michael;  Wagner, Anthony D.;  Aigner, Ludwig;  Galasko, Douglas R.;  Davis, Mark M.;  Wyss-Coray, Tony
收藏  |  浏览/下载:32/0  |  提交时间:2020/07/03

The discovery of superconductivity at 200 kelvin in the hydrogen sulfide system at high pressures(1) demonstrated the potential of hydrogen-rich materials as high-temperature superconductors. Recent theoretical predictions of rare-earth hydrides with hydrogen cages(2,3) and the subsequent synthesis of LaH10 with a superconducting critical temperature (T-c) of 250 kelvin(4,5) have placed these materials on the verge of achieving the long-standing goal of room-temperature superconductivity. Electrical and X-ray diffraction measurements have revealed a weakly pressure-dependent T-c for LaH10 between 137 and 218 gigapascals in a structure that has a face-centred cubic arrangement of lanthanum atoms(5). Here we show that quantum atomic fluctuations stabilize a highly symmetrical Fm (3) over barm crystal structure over this pressure range. The structure is consistent with experimental findings and has a very large electron-phonon coupling constant of 3.5. Although ab initio classical calculations predict that this Fm (3) over barm structure undergoes distortion at pressures below 230 gigapascals(2,3,) yielding a complex energy landscape, the inclusion of quantum effects suggests that it is the true ground-state structure. The agreement between the calculated and experimental Tc values further indicates that this phase is responsible for the superconductivity observed at 250 kelvin. The relevance of quantum fluctuations calls into question many of the crystal structure predictions that have been made for hydrides within a classical approach and that currently guide the experimental quest for room-temperature superconductivity(6-8). Furthermore, we find that quantum effects are crucial for the stabilization of solids with high electron-phonon coupling constants that could otherwise be destabilized by the large electron-phonon interaction(9), thus reducing the pressures required for their synthesis.


  
Climate Change Drives Widespread and Rapid Thermokarst Development in Very Cold Permafrost in the Canadian High Arctic 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2019, 46 (12) : 6681-6689
作者:  Farquharson, Louise M.;  Romanovsky, Vladimir E.;  Cable, William L.;  Walker, Donald A.;  Kokelj, Steven V.;  Nicolsky, Dmitry
收藏  |  浏览/下载:22/0  |  提交时间:2019/11/26
permafrost  Arctic  thermokarst  monitoring  ground temperature  
Elevation-dependent sensible heat flux trend over the Tibetan Plateau and its possible causes 期刊论文
CLIMATE DYNAMICS, 2019, 52: 3997-4009
作者:  Zhu, Lihua;  Huang, Gang;  Fan, Guangzhou;  Que, Xia;  Wang, Zhibiao;  Hua, Wei
收藏  |  浏览/下载:15/0  |  提交时间:2019/11/26
Altitude dependence  Surface sensible heat trend  Tibetan Plateau  The difference of ground-air temperature  Surface wind speed  
Analysis of the long-term high-resolution infrared radiation sounder land surface temperature against ground measurements during 1980-2009 in the Poyang Lake basin, China 期刊论文
INTERNATIONAL JOURNAL OF CLIMATOLOGY, 2018, 38 (15) : 5733-5745
作者:  Wang, Guojie;  Shen, Chengcheng;  Pan, Jian;  Lou, Dan;  Hagan, Daniel F. T.;  Parinussa, Robert M.;  Zhan, Mingjin;  Su, Buda;  Jiang, Tong
收藏  |  浏览/下载:25/0  |  提交时间:2019/04/09
evaluation  ground measurement  land surface temperature  Poyang Lake basin  remote sensing  
Aboveground carbon sequestration in dry temperate forests varies with climate not fire regime 期刊论文
GLOBAL CHANGE BIOLOGY, 2018, 24 (9) : 4280-4292
作者:  Gordon, Christopher E.;  Bendall, Eli R.;  Stares, Mitchell G.;  Collins, Luke;  Bradstock, Ross A.
收藏  |  浏览/下载:14/0  |  提交时间:2019/04/09
Above-ground carbon  climate change  CO  (2)  fire frequency  fire severity  mean annual precipitation  mean annual temperature  
Remote sensing of the lightning heating effect duration with ground-based microwave radiometer 期刊论文
ATMOSPHERIC RESEARCH, 2018, 205: 26-32
作者:  Jiang, Sulin;  Pan, Yun;  Lei, Lianfa;  Ma, Lina;  Li, Qing;  Wang, Zhenhui
收藏  |  浏览/下载:22/0  |  提交时间:2019/04/09
Lightning heating effect duration  Ground-based microwave radiometer  Brightness temperature pulse  
Spurious Additional Warming Reconstructed From Borehole Temperatures Corrected for the Effect of the Last Glacial Cycle 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2018, 45 (6) : 2780-2785
作者:  Safanda, Jan
收藏  |  浏览/下载:11/0  |  提交时间:2019/04/09
borehole temperatures  ground surface temperature history  effect of the Last Glacial Cycle  
Spatiotemporal variations of differences between surface air and ground temperatures in China 期刊论文
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2017, 122 (15)
作者:  Wang, Yanjiao;  Hu, Zeng-Zhen;  Yan, Feng
收藏  |  浏览/下载:10/0  |  提交时间:2019/04/09
ground surface temperature  surface air temperature  land and atmosphere temperature difference  spatiotemporal variations  shift in winter around 2004-2005  snow impact