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Aerosol classification in Europe, Middle East, North Africa and Arabian Peninsula based on AERONET Version 3 期刊论文
ATMOSPHERIC RESEARCH, 2020, 239
作者:  Logothetis, Stavros-Andreas;  Salamalikis, Vasileios;  Kazantzidis, Andreas
收藏  |  浏览/下载:13/0  |  提交时间:2020/08/18
Aerosol  Climatology  Aerosol classification  AERONET  Aerosol optical properties  
Assessment of GPM IMERG and radar quantitative precipitation estimation (QPE) products using dense rain gauge observations in the Guangdong-Hong Kong-Macao Greater Bay Area, China 期刊论文
ATMOSPHERIC RESEARCH, 2020, 236
作者:  Li, Xue;  Chen, Yangbo;  Wang, Huanyu;  Zhang, Yueyuan
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/02
Precipitation  GPM  IMERG  Radar  QPE  
Ordinal regression algorithms for the analysis of convective situations over Madrid-Barajas airport 期刊论文
ATMOSPHERIC RESEARCH, 2020, 236
作者:  Guijo-Rubio, D.;  Casanova-Mateo, C.;  Sanz-Justo, J.;  Gutierrez, P. A.;  Cornejo-Bueno, S.;  Hervas, C.;  Salcedo-Sanz, S.
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/02
Convective clouds  Convective analysis  Airports  Machine learning techniques  Ordinal regression  
Multi-model ensemble predictions of precipitation and temperature using machine learning algorithms 期刊论文
ATMOSPHERIC RESEARCH, 2020, 236
作者:  Ahmed, Kamal;  Sachindra, D. A.;  Shahid, Shamsuddin;  Iqbal, Zafar;  Nawaz, Nadeem;  Khan, Najeebullah
收藏  |  浏览/下载:16/0  |  提交时间:2020/07/02
General circulation models  Multi-model ensemble  Taylor skill score  Machine learning algorithms  Temperature and precipitation  Pakistan  
The water lily genome and the early evolution of flowering plants 期刊论文
NATURE, 2020, 577 (7788) : 79-+
作者:  Zhang, Liangsheng;  Chen, Fei;  Zhang, Xingtan;  Li, Zhen;  Zhao, Yiyong;  Lohaus, Rolf;  Chang, Xiaojun;  Dong, Wei;  Ho, Simon Y. W.;  Liu, Xing;  Song, Aixia;  Chen, Junhao;  Guo, Wenlei;  Wang, Zhengjia;  Zhuang, Yingyu;  Wang, Haifeng;  Chen, Xuequn;  Hu, Juan;  Liu, Yanhui;  Qin, Yuan;  Wang, Kai;  Dong, Shanshan;  Liu, Yang;  Zhang, Shouzhou;  Yu, Xianxian;  Wu, Qian;  Wang, Liangsheng;  Yan, Xueqing;  Jiao, Yuannian;  Kong, Hongzhi;  Zhou, Xiaofan;  Yu, Cuiwei;  Chen, Yuchu;  Li, Fan;  Wang, Jihua;  Chen, Wei;  Chen, Xinlu;  Jia, Qidong;  Zhang, Chi;  Jiang, Yifan;  Zhang, Wanbo;  Liu, Guanhua;  Fu, Jianyu;  Chen, Feng;  Ma, Hong;  Van de Peer, Yves;  Tang, Haibao
收藏  |  浏览/下载:16/0  |  提交时间:2020/07/03

Water lilies belong to the angiosperm order Nymphaeales. Amborellales, Nymphaeales and Austrobaileyales together form the so-called ANA-grade of angiosperms, which are extant representatives of lineages that diverged the earliest from the lineage leading to the extant mesangiosperms(1-3). Here we report the 409-megabase genome sequence of the blue-petal water lily (Nymphaea colorata). Our phylogenomic analyses support Amborellales and Nymphaeales as successive sister lineages to all other extant angiosperms. The N. colorata genome and 19 other water lily transcriptomes reveal a Nymphaealean whole-genome duplication event, which is shared by Nymphaeaceae and possibly Cabombaceae. Among the genes retained from this whole-genome duplication are homologues of genes that regulate flowering transition and flower development. The broad expression of homologues of floral ABCE genes in N. colorata might support a similarly broadly active ancestral ABCE model of floral organ determination in early angiosperms. Water lilies have evolved attractive floral scents and colours, which are features shared with mesangiosperms, and we identified their putative biosynthetic genes in N. colorata. The chemical compounds and biosynthetic genes behind floral scents suggest that they have evolved in parallel to those in mesangiosperms. Because of its unique phylogenetic position, the N. colorata genome sheds light on the early evolution of angiosperms.


  
Operation of a silicon quantum processor unit cell above one kelvin 期刊论文
NATURE, 2020, 580 (7803) : 350-+
作者:  Han, Kyuho;  Pierce, Sarah E.;  Li, Amy;  Spees, Kaitlyn;  Anderson, Grace R.;  Seoane, Jose A.;  Lo, Yuan-Hung;  Dubreuil, Michael;  Olivas, Micah;  Kamber, Roarke A.;  Wainberg, Michael;  Kostyrko, Kaja;  Kelly, Marcus R.;  Yousefi, Maryam;  Simpkins, Scott W.;  Yao, David
收藏  |  浏览/下载:11/0  |  提交时间:2020/07/03

Quantum computers are expected to outperform conventional computers in several important applications, from molecular simulation to search algorithms, once they can be scaled up to large numbers-typically millions-of quantum bits (qubits)(1-3). For most solid-state qubit technologies-for example, those using superconducting circuits or semiconductor spins-scaling poses a considerable challenge because every additional qubit increases the heat generated, whereas the cooling power of dilution refrigerators is severely limited at their operating temperature (less than 100 millikelvin)(4-6). Here we demonstrate the operation of a scalable silicon quantum processor unit cell comprising two qubits confined to quantum dots at about 1.5 kelvin. We achieve this by isolating the quantum dots from the electron reservoir, and then initializing and reading the qubits solely via tunnelling of electrons between the two quantum dots(7-9). We coherently control the qubits using electrically driven spin resonance(10,11) in isotopically enriched silicon(12 28)Si, attaining single-qubit gate fidelities of 98.6 per cent and a coherence time of 2 microseconds during '  hot'  operation, comparable to those of spin qubits in natural silicon at millikelvin temperatures(13-16). Furthermore, we show that the unit cell can be operated at magnetic fields as low as 0.1 tesla, corresponding to a qubit control frequency of 3.5 gigahertz, where the qubit energy is well below the thermal energy. The unit cell constitutes the core building block of a full-scale silicon quantum computer and satisfies layout constraints required by error-correction architectures(8),(17). Our work indicates that a spin-based quantum computer could be operated at increased temperatures in a simple pumped He-4 system (which provides cooling power orders of magnitude higher than that of dilution refrigerators), thus potentially enabling the integration of classical control electronics with the qubit array(18,19).


  
Spatial mapping of the provenance of storm dust: Application of data mining and ensemble modelling 期刊论文
ATMOSPHERIC RESEARCH, 2020, 233
作者:  Gholami, Hamid;  Mohamadifar, Aliakbar;  Collins, Adrian L.
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/02
Dust provenance  Spatial modelling  Data mining algorithms  Multicollinearity  Receiver operating characteristic  Ensemble modelling  R software  
Nonuniqueness in a Single-Column Model for Moist Convection 期刊论文
JOURNAL OF THE ATMOSPHERIC SCIENCES, 2020, 77 (3) : 1001-1018
作者:  Turner, M. R.;  Norbury, J.
收藏  |  浏览/下载:1/0  |  提交时间:2020/07/02
Convection  
Merging regional and global aerosol optical depth records from major available satellite products 期刊论文
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2020, 20 (4) : 2031-2056
作者:  Sogacheva, Larisa;  Popp, Thomas;  Sayer, Andrew M.;  Dubovik, Oleg;  Garay, Michael J.;  Heckel, Andreas;  Hsu, N. Christina;  Jethva, Hiren;  Kahn, Ralph A.;  Kolmonen, Pekka;  Kosmale, Miriam;  de Leeuw, Gerrit;  Levy, Robert C.;  Litvinov, Pavel;  Lyapustin, Alexei;  North, Peter;  Torres, Omar;  Arola, Antti
收藏  |  浏览/下载:50/0  |  提交时间:2020/07/02
Coherent electrical control of a single high-spin nucleus in silicon 期刊论文
NATURE, 2020, 579 (7798) : 205-+
作者:  Dedoussi, Irene C.;  Eastham, Sebastian D.;  Monier, Erwan;  Barrett, Steven R. H.
收藏  |  浏览/下载:10/0  |  提交时间:2020/07/03

Nuclear spins are highly coherent quantum objects. In large ensembles, their control and detection via magnetic resonance is widely exploited, for example, in chemistry, medicine, materials science and mining. Nuclear spins also featured in early proposals for solid-state quantum computers(1) and demonstrations of quantum search(2) and factoring(3) algorithms. Scaling up such concepts requires controlling individual nuclei, which can be detected when coupled to an electron(4-6). However, the need to address the nuclei via oscillating magnetic fields complicates their integration in multi-spin nanoscale devices, because the field cannot be localized or screened. Control via electric fields would resolve this problem, but previous methods(7-9) relied on transducing electric signals into magnetic fields via the electron-nuclear hyperfine interaction, which severely affects nuclear coherence. Here we demonstrate the coherent quantum control of a single Sb-123 (spin-7/2) nucleus using localized electric fields produced within a silicon nanoelectronic device. The method exploits an idea proposed in 1961(10) but not previously realized experimentally with a single nucleus. Our results are quantitatively supported by a microscopic theoretical model that reveals how the purely electrical modulation of the nuclear electric quadrupole interaction results in coherent nuclear spin transitions that are uniquely addressable owing to lattice strain. The spin dephasing time, 0.1 seconds, is orders of magnitude longer than those obtained by methods that require a coupled electron spin to achieve electrical driving. These results show that high-spin quadrupolar nuclei could be deployed as chaotic models, strain sensors and hybrid spin-mechanical quantum systems using all-electrical controls. Integrating electrically controllable nuclei with quantum dots(11,12) could pave the way to scalable, nuclear- and electron-spin-based quantum computers in silicon that operate without the need for oscillating magnetic fields.