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Fast sulfate formation from oxidation of SO2 by NO2 and HONO observed in Beijing haze 期刊论文
NATURE COMMUNICATIONS, 2020, 11 (1)
作者:  Wang, Junfeng;  Li, Jingyi;  Ye, Jianhuai;  Zhao, Jian;  Wu, Yangzhou;  Hu, Jianlin;  Liu, Dantong;  Nie, Dongyang;  Shen, Fuzhen;  Huang, Xiangpeng;  Huang, Dan Dan;  Ji, Dongsheng;  Sun, Xu;  Xu, Weiqi;  Guo, Jianping;  Song, Shaojie;  Qin, Yiming;  Liu, Pengfei;  Turner, Jay R.;  Lee, Hyun Chul;  Hwang, Sungwoo;  Liao, Hong;  Martin, Scot T.;  Zhang, Qi;  Chen, Mindong;  Sun, Yele;  Ge, Xinlei;  Jacob, Daniel J.
收藏  |  浏览/下载:18/0  |  提交时间:2020/06/09
A big data approach to improving the vehicle emission inventory in China 期刊论文
NATURE COMMUNICATIONS, 2020, 11 (1)
作者:  Deng, Fanyuan;  Lv, Zhaofeng;  Qi, Lijuan;  Wang, Xiaotong;  Shi, Mengshuang;  Liu, Huan
收藏  |  浏览/下载:9/0  |  提交时间:2020/06/09
Strain engineering and epitaxial stabilization of halide perovskites 期刊论文
NATURE, 2020, 577 (7789) : 209-+
作者:  Chen, Yimu;  Lei, Yusheng;  Li, Yuheng;  Yu, Yugang;  Cai, Jinze;  Chiu, Ming-Hui;  Rao, Rahul;  Gu, Yue;  Wang, Chunfeng;  Choi, Woojin;  Hu, Hongjie;  Wang, Chonghe;  Li, Yang;  Song, Jiawei;  Zhang, Jingxin;  Qi, Baiyan;  Lin, Muyang;  Zhang, Zhuorui;  Islam, Ahmad E.;  Maruyama, Benji;  Dayeh, Shadi;  Li, Lain-Jong;  Yang, Kesong;  Lo, Yu-Hwa;  Xu, Sheng
收藏  |  浏览/下载:26/0  |  提交时间:2020/07/03

Strain engineering is a powerful tool with which to enhance semiconductor device performance(1,2). Halide perovskites have shown great promise in device applications owing to their remarkable electronic and optoelectronic properties(3-5). Although applying strain to halide perovskites has been frequently attempted, including using hydrostatic pressurization(6-8), electrostriction(9), annealing(10-12), van der Waals force(13), thermal expansion mismatch(14), and heat-induced substrate phase transition(15), the controllable and device-compatible strain engineering of halide perovskites by chemical epitaxy remains a challenge, owing to the absence of suitable lattice-mismatched epitaxial substrates. Here we report the strained epitaxial growth of halide perovskite single-crystal thin films on lattice-mismatched halide perovskite substrates. We investigated strain engineering of a-formamidinium lead iodide (alpha-FAPbI(3)) using both experimental techniques and theoretical calculations. By tailoring the substrate composition-and therefore its lattice parameter-a compressive strain as high as 2.4 per cent is applied to the epitaxial alpha-FAPbI(3) thin film. We demonstrate that this strain effectively changes the crystal structure, reduces the bandgap and increases the hole mobility of alpha-FAPbI(3). Strained epitaxy is also shown to have a substantial stabilization effect on the alpha-FAPbI(3) phase owing to the synergistic effects of epitaxial stabilization and strain neutralization. As an example, strain engineering is applied to enhance the performance of an alpha-FAPbI(3)-based photodetector.


  
CAN THE WORLD MAKE ENOUGH CORONAVIRUS VACCINE? 期刊论文
NATURE, 2020, 580 (7805) : 578-580
作者:  Zhao, Chuangqi;  Zhang, Pengchao;  Zhou, Jiajia;  Qi, Shuanhu;  Yamauchi, Yoshihiro;  Shi, Ruirui;  Fang, Ruochen;  Ishida, Yasuhiro;  Wang, Shutao;  Tomsia, Antoni P.;  Liu, Mingjie;  Jiang, Lei
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/03

Researchers warn production constraints and hoarding could limit SARS-CoV-2 vaccine supplies.


Researchers warn production constraints and hoarding could limit SARS-CoV-2 vaccine supplies.


  
Accelerated discovery of CO2 electrocatalysts using active machine learning 期刊论文
NATURE, 2020, 581 (7807) : 178-+
作者:  Lan, Jun;  Ge, Jiwan;  Yu, Jinfang;  Shan, Sisi;  Zhou, Huan;  Fan, Shilong;  Zhang, Qi;  Shi, Xuanling;  Wang, Qisheng;  Zhang, Linqi;  Wang, Xinquan
收藏  |  浏览/下载:88/0  |  提交时间:2020/07/03

The rapid increase in global energy demand and the need to replace carbon dioxide (CO2)-emitting fossil fuels with renewable sources have driven interest in chemical storage of intermittent solar and wind energy(1,2). Particularly attractive is the electrochemical reduction of CO2 to chemical feedstocks, which uses both CO2 and renewable energy(3-8). Copper has been the predominant electrocatalyst for this reaction when aiming for more valuable multi-carbon products(9-16), and process improvements have been particularly notable when targeting ethylene. However, the energy efficiency and productivity (current density) achieved so far still fall below the values required to produce ethylene at cost-competitive prices. Here we describe Cu-Al electrocatalysts, identified using density functional theory calculations in combination with active machine learning, that efficiently reduce CO2 to ethylene with the highest Faradaic efficiency reported so far. This Faradaic efficiency of over 80 per cent (compared to about 66 per cent for pure Cu) is achieved at a current density of 400 milliamperes per square centimetre (at 1.5 volts versus a reversible hydrogen electrode) and a cathodic-side (half-cell) ethylene power conversion efficiency of 55 +/- 2 per cent at 150 milliamperes per square centimetre. We perform computational studies that suggest that the Cu-Al alloys provide multiple sites and surface orientations with near-optimal CO binding for both efficient and selective CO2 reduction(17). Furthermore, in situ X-ray absorption measurements reveal that Cu and Al enable a favourable Cu coordination environment that enhances C-C dimerization. These findings illustrate the value of computation and machine learning in guiding the experimental exploration of multi-metallic systems that go beyond the limitations of conventional single-metal electrocatalysts.


  
Hydropower Production Benefits More From 1.5 degrees C than 2 degrees C Climate Scenario 期刊论文
WATER RESOURCES RESEARCH, 2020, 56 (5)
作者:  Meng, Ying;  Liu, Junguo;  Leduc, Sylvain;  Mesfun, Sennai;  Kraxner, Florian;  Mao, Ganquan;  Qi, Wei;  Wang, Zifeng
收藏  |  浏览/下载:9/0  |  提交时间:2020/05/13
global warming  hydropower(sic)hydro-economic modeling  optimization model  ISIMIP  PCR-GLOBWB  protected areas  
Structure and mechanism of human diacylglycerol O-acyltransferase 1 期刊论文
NATURE, 2020, 581 (7808) : 329-+
作者:  Wu, Fan;  Zhao, Su;  Yu, Bin;  Chen, Yan-Mei;  Wang, Wen;  Song, Zhi-Gang;  Hu, Yi;  Tao, Zhao-Wu;  Tian, Jun-Hua;  Pei, Yuan-Yuan;  Yuan, Ming-Li;  Zhang, Yu-Ling;  Dai, Fa-Hui;  Liu, Yi;  Wang, Qi-Min;  Zheng, Jiao-Jiao;  Xu, Lin;  Holmes, Edward C.;  Zhang, Yong-Zhen
收藏  |  浏览/下载:24/0  |  提交时间:2020/07/03

The structure of human diacylglycerol O-acyltransferase 1, a membrane protein that synthesizes triacylglycerides, is solved with cryo-electron microscopy, providing insight into its function and mechanism of enzymatic activity.


Diacylglycerol O-acyltransferase 1 (DGAT1) synthesizes triacylglycerides and is required for dietary fat absorption and fat storage in humans(1). DGAT1 belongs to the membrane-bound O-acyltransferase (MBOAT) superfamily, members of which are found in all kingdoms of life and are involved in the acylation of lipids and proteins(2,3). How human DGAT1 and other mammalian members of the MBOAT family recognize their substrates and catalyse their reactions is unknown. The absence of three-dimensional structures also hampers rational targeting of DGAT1 for therapeutic purposes. Here we present the cryo-electron microscopy structure of human DGAT1 in complex with an oleoyl-CoA substrate. Each DGAT1 protomer has nine transmembrane helices, eight of which form a conserved structural fold that we name the MBOAT fold. The MBOAT fold in DGAT1 forms a hollow chamber in the membrane that encloses highly conserved catalytic residues. The chamber has separate entrances for each of the two substrates, fatty acyl-CoA and diacylglycerol. DGAT1 can exist as either a homodimer or a homotetramer and the two forms have similar enzymatic activity. The N terminus of DGAT1 interacts with the neighbouring protomer and these interactions are required for enzymatic activity.


  
The online competition between pro- and anti-vaccination views 期刊论文
NATURE, 2020, 582 (7811) : 230-+
作者:  Wu, Fan;  Zhao, Su;  Yu, Bin;  Chen, Yan-Mei;  Wang, Wen;  Song, Zhi-Gang;  Hu, Yi;  Tao, Zhao-Wu;  Tian, Jun-Hua;  Pei, Yuan-Yuan;  Yuan, Ming-Li;  Zhang, Yu-Ling;  Dai, Fa-Hui;  Liu, Yi;  Wang, Qi-Min;  Zheng, Jiao-Jiao;  Xu, Lin;  Holmes, Edward C.;  Zhang, Yong-Zhen
收藏  |  浏览/下载:10/0  |  提交时间:2020/07/03

Insights into the interactions between pro- and anti-vaccination clusters on Facebook can enable policies and approaches that attempt to interrupt the shift to anti-vaccination views and persuade undecided individuals to adopt a pro-vaccination stance.


Distrust in scientific expertise(1-14) is dangerous. Opposition to vaccination with a future vaccine against SARS-CoV-2, the causal agent of COVID-19, for example, could amplify outbreaks(2-4), as happened for measles in 2019(5,6). Homemade remedies(7,8) and falsehoods are being shared widely on the Internet, as well as dismissals of expert advice(9-11). There is a lack of understanding about how this distrust evolves at the system level(13,14). Here we provide a map of the contention surrounding vaccines that has emerged from the global pool of around three billion Facebook users. Its core reveals a multi-sided landscape of unprecedented intricacy that involves nearly 100 million individuals partitioned into highly dynamic, interconnected clusters across cities, countries, continents and languages. Although smaller in overall size, anti-vaccination clusters manage to become highly entangled with undecided clusters in the main online network, whereas pro-vaccination clusters are more peripheral. Our theoretical framework reproduces the recent explosive growth in anti-vaccination views, and predicts that these views will dominate in a decade. Insights provided by this framework can inform new policies and approaches to interrupt this shift to negative views. Our results challenge the conventional thinking about undecided individuals in issues of contention surrounding health, shed light on other issues of contention such as climate change(11), and highlight the key role of network cluster dynamics in multi-species ecologies(15).


  
Very regular high-frequency pulsation modes in young intermediate-mass stars 期刊论文
NATURE, 2020, 581 (7807) : 147-+
作者:  Zhao, Chuangqi;  Zhang, Pengchao;  Zhou, Jiajia;  Qi, Shuanhu;  Yamauchi, Yoshihiro;  Shi, Ruirui;  Fang, Ruochen;  Ishida, Yasuhiro;  Wang, Shutao;  Tomsia, Antoni P.;  Jiang, Lei;  Liu, Mingjie
收藏  |  浏览/下载:10/0  |  提交时间:2020/07/03

Asteroseismology probes the internal structures of stars by using their natural pulsation frequencies(1). It relies on identifying sequences of pulsation modes that can be compared with theoretical models, which has been done successfully for many classes of pulsators, including low-mass solar-type stars(2), red giants(3), high-mass stars(4) and white dwarfs(5). However, a large group of pulsating stars of intermediate mass-the so-called delta Scuti stars-have rich pulsation spectra for which systematic mode identification has not hitherto been possible(6,7). This arises because only a seemingly random subset of possible modes are excited and because rapid rotation tends to spoil regular patterns(8-10). Here we report the detection of remarkably regular sequences of high-frequency pulsation modes in 60 intermediate-mass main-sequence stars, which enables definitive mode identification. The space motions of some of these stars indicate that they are members of known associations of young stars, as confirmed by modelling of their pulsation spectra.


The pulsation spectra of intermediate-mass stars (so-called delta Scuti stars) have been challenging to analyse, but new observations of 60 such stars reveal remarkably regular sequences of high-frequency pulsation modes.


  
Spin squeezing of 10(11) atoms by prediction and retrodiction measurements 期刊论文
NATURE, 2020, 581 (7807) : 159-+
作者:  Lan, Jun;  Ge, Jiwan;  Yu, Jinfang;  Shan, Sisi;  Zhou, Huan;  Fan, Shilong;  Zhang, Qi;  Shi, Xuanling;  Wang, Qisheng;  Zhang, Linqi;  Wang, Xinquan
收藏  |  浏览/下载:7/0  |  提交时间:2020/07/03

The measurement sensitivity of quantum probes using N uncorrelated particles is restricted by the standard quantum limit(1), which is proportional to 1/root N. This limit, however, can be overcome by exploiting quantum entangled states, such as spin-squeezed states(2). Here we report the measurement-based generation of a quantum state that exceeds the standard quantum limit for probing the collective spin of 10(11) rubidium atoms contained in a macroscopic vapour cell. The state is prepared and verified by sequences of stroboscopic quantum non-demolition (QND) measurements. We then apply the theory of past quantum states(3,4) to obtain spin state information from the outcomes of both earlier and later QND measurements. Rather than establishing a physically squeezed state in the laboratory, the past quantum state represents the combined system information from these prediction and retrodiction measurements. This information is equivalent to a noise reduction of 5.6 decibels and a metrologically relevant squeezing of 4.5 decibels relative to the coherent spin state. The past quantum state yields tighter constraints on the spin component than those obtained by conventional QND measurements. Our measurement uses 1,000 times more atoms than previous squeezing experiments(5-10), with a corresponding angular variance of the squeezed collective spin of 4.6 x 10(-13) radians squared. Although this work is rooted in the foundational theory of quantum measurements, it may find practical use in quantum metrology and quantum parameter estimation, as we demonstrate by applying our protocol to quantum enhanced atomic magnetometry.