Subtle but important differences are identified between the 1997/1998 and 2015/2016 extreme El Niños that reflect fundamental differences in their underlying dynamics. The 1997/1998 event is found to ...evolve following the eastern Pacific El Niño dynamics that relies on basin‐wide thermocline variations, whereas the 2015/2016 event involves additionally the central Pacific (CP) El Niño dynamics that depends on subtropical forcing. The stronger CP dynamics during the 2015/2016 event resulted in its sea surface temperature (SST) anomalies lingering around the International Date Line during the decaying phase, which is in contrast to the retreat of the anomalies toward the South American Coast during the decaying phase of the 1997/1998 event. The different SST evolution excited different wave trains resulting in the western U.S. not receiving the same above‐normal rainfall during the 2015/2016 El Niño as it did during the 1997/1998 El Niño. Ensemble model experiments are conducted to confirm the different climate impacts of the two El Niños.
Key Points
The 1997/1998 event is the strongest EP El Niño, while the 2015/2016 event is the strongest mixed EP and CP El Niño ever recorded
The two events exhibit subtle differences in their equatorial SST evolution that reflects fundamental differences in the underlying dynamics
The SST differences led to large differences in tropical convection, resulting in different impacts on North American climate
The lithium metal anode has attracted soaring attention as an ideal battery anode. Unfortunately, nonuniform Li nucleation results in uncontrollable growth of dendritic Li, which incurs serious ...safety issues and poor electrochemical performance, hindering its practical applications. Herein, this study shows that uniform Li nucleation/growth can be induced by an ultralight 3D current collector consisting of in situ nitrogen‐doped graphitic carbon foams (NGCFs) to realize suppressing dendritic Li growth at the nucleating stage. The N‐containing functional groups guide homogenous growth of Li nucleus nanoparticles and the initial Li nucleus seed layer regulates the following well‐distributed Li growth. Benefiting from such favorable Li growth behavior, superior electrochemical performance can be achieved as evidenced by the high Coulombic efficiency (≈99.6% for 300 cycles), large capacity (10 mA h cm−2, 3140 mA h g−1NGCF‐Li), and ultralong lifespan (>1200 h) together with low overpotential (<25 mV at 3 mA cm−2); even under a high current density up to 10 mA cm−2, it still displays low overpotential of 62 mV.
Uniform Li nucleation/growth can be induced by an ultralight 3D current collector consisting of in situ nitrogen‐doped graphitic carbon foams for high‐performance lithium‐metal anodes. The N‐containing functional groups guide initial homogeneous formation of Li nanoparticles and the initial nucleus seed layer regulates the even Li growth that follows. Significantly improved electrochemical performance can be achieved.
In this study, we evaluate the intensity of the Central‐Pacific (CP) and Eastern‐Pacific (EP) types of El Niño‐Southern Oscillation (ENSO) simulated in the pre‐industrial, historical, and the ...Representative Concentration Pathways (RCP) 4.5 experiments of the Coupled Model Intercomparison Project Phase 5 (CMIP5). Compared to the CMIP3 models, the pre‐industrial simulations of the CMIP5 models are found to (1) better simulate the observed spatial patterns of the two types of ENSO and (2) have a significantly smaller inter‐model diversity in ENSO intensities. The decrease in the CMIP5 model discrepancies is particularly obvious in the simulation of the EP ENSO intensity, although it is still more difficult for the models to reproduce the observed EP ENSO intensity than the observed CP ENSO intensity. Ensemble means of the CMIP5 models indicate that the intensity of the CP ENSO increases steadily from the pre‐industrial to the historical and the RCP4.5 simulations, but the intensity of the EP ENSO increases from the pre‐industrial to the historical simulations and then decreases in the RCP4.5 projections. The CP‐to‐EP ENSO intensity ratio, as a result, is almost the same in the pre‐industrial and historical simulations but increases in the RCP4.5 simulation.
Key Points
Smaller inter‐model diversity of ENSO intensities in CMIP5 than in CMIP3
Decrease in the diversity is particularly significant for the simulated EP ENSO
Different response of EP and CP ENSO to global warming
Although tobacco smoking has been reported as a risk factor for liver cancer, few studies have specifically explored the association among Chinese females and the potential interaction between ...smoking and other risk factors. A population‐based case–control study was conducted and 2,011 liver cancer cases and 7,933 healthy controls were enrolled in Jiangsu, China from 2003 to 2010. Epidemiological data were collected, and serum hepatitis B surface antigen (HBsAg) and anti‐HCV antibody were measured. Unconditional logistic regression was used to examine association and potential interaction, while semi‐Bayes (SB) method was employed to make estimates more conservative. The prevalence of serum HBsAg positivity was 43.2% among cases and 6.5% among controls. The adjusted odds ratios (OR) for ever smoking were 1.62 (95% confidence interval CI: 1.33–1.96) among male and 0.82 (95% CI: 0.53–1.26) among female. Age at first cigarette, duration of smoking and pack‐years of smoking were all significantly associated with liver cancer among men. Compared to HBsAg‐negative never smokers, the adjusted ORs were 1.25 (95% CI: 1.03–1.52) for HBsAg‐negative ever smokers, 7.66 (95% CI: 6.05–9.71) for HBsAg‐positive never smokers, and 15.68 (95% CI: 12.06–20.39) for HBsAg‐positive ever smokers. These different odds ratios indicated super‐additive (RERI: 7.77, 95% CI: 3.81–11.73) and super‐multiplicative interactions (ROR: 1.64, 95% CI: 1.17–2.30) between hepatitis B virus (HBV) infection and tobacco smoking. Most associations and interactions detected remained statistically significant after SB adjustments. Tobacco smoking and HBV infection positively interact in the development of liver cancer.
What's new?
Tobacco smoking is a major risk factor for various cancer types, including liver cancer. Half of new liver cancer cases reported annually worldwide occur in China, where the prevalence of smoking and hepatitis B virus (HBV) infection are high. Here, associations between tobacco smoking and liver cancer and interactions between smoking and other risk factors were examined in a Chinese population. Significant interactions were detected between smoking and HBV infection. Analyses by gender indicated that associations between smoking and liver cancer existed primarily among men, who were more likely than women to have been ever smokers or current smokers.
The composite analyses during 1950–2016 show that the impacts of El Niño on the western Pacific subtropical high (WPSH) are different among the Eastern Pacific type, Central Pacific type‐I (CP‐I), ...and Central Pacific type‐II (CP‐II). The three types of El Niño produce distinct impacts on WPSH due to the varying importance of the Northwestern Pacific coupling, Indian Ocean capacitor, and Maritime Continent mechanisms. The different enhancements and cancellations among these three mechanisms are related to differences in SST anomaly locations and Indian Ocean conditions among the El Niño types. The CP‐II El Niño becomes the most influential type of El Niño, while the CP‐I El Niño becomes the least influential type. The different impacts and mechanisms for the CP‐I and CP‐II types of El Niño imply that these two subtypes of CP El Niño may involve different forcing from the Indian Ocean and extratropical Pacific for their generation.
Plain Language Summary
It is now well recognized that there exists a conventional Eastern Pacific type and an emerging Central Pacific type of El Niño. Recent studies have suggested that the CP El Niño should be further separated into two subtypes. It is shown here that these three El Niño–Southern Oscillation types produce distinct impacts on the western Pacific subtropical high (WPSH). The conventional views of El Niño's impacts on the WPSH and their underlying mechanisms need to be revised to take into account of the El Niño diversity. This study also offers new insights into the generation dynamics of the two subtypes of the CP El Niño. We find that the two subtypes of CP El Niño differ not only in their sea surface temperature anomalies in the northeastern Pacific but also in the Indian Ocean.
Key Points
El Niño diversity invokes NW Pacific coupling, Indian Ocean capacitor, and MC mechanism to produce distinct impacts on WPSH
The changing importance of these mechanisms is caused by different SST anomaly in Pacific and Indian Oceans during various El Niño types
The different impacts indicate that CP‐I and CP‐II El Niños are forced by Indian Ocean and extratropical Pacific, respectively
A 2,200‐year CESM1 pre‐industrial simulation is used to contrast Antarctic sea ice concentration (SIC) variations between the first and second austral winters of multi‐year La Niñas. The typical SIC ...anomaly pattern induced by single‐year La Niñas appears only during the second austral winter of multi‐year La Niñas. A similar pattern, but zonally shifted compared to the typical one, is found during the first winter and exhibits a tripolar pattern with anomaly centers over the Ross, Amundsen‐Bellingshausen, and Weddell Seas. The shift is a result of the pre‐onset conditions associated with multi‐year La Niñas that excites unique atmospheric circulation modes during the first winter. The distinct zonally‐shifted SIC anomaly pattern is observed in four of the six multi‐year La Niña events during the period 1979–2020. These results suggest that it is helpful to separate La Niñas into single and multi‐year events to better understand the La Niña impacts on Antarctic climate.
Plain Language Summary
La Niña events are characterized by abnormal cooling of sea surface waters in the tropical Pacific Ocean. Recently, more La Niña events have been observed to persist for multiple year. In this study, we analyze a long‐term climate model simulation to show that multi‐year La Niñas produce a different impact on Antarctic sea ice concentrations (SIC) than single‐year La Niñas. The typical SIC impact produced by single‐year La Niñas appears only during the second austral winter of multi‐year La Niñas. In contrast, during the first winter of multi‐year La Niñas the pattern is shifted westward and is characterized by a distinct tripolar pattern with anomaly centers over the Ross, Amundsen‐Bellingshausen, Weddell Seas. The different impact pattern during the first winter is caused by the different atmospheric wave trains excited by the different Indian Ocean conditions during the first and second winters of multi‐year events. The distinct impacts and impact mechanisms found in the climate model are also found in the observations. Four out of the six multi‐year La Niña events observed during 1979–2020 exhibit this zonally‐shifted SIC anomaly pattern during their first winters. The increasing occurrence of multi‐year La Niña events may affect Antarctic sea ice patterns in new ways.
Key Points
The typical sea ice anomaly pattern appears during the second winter of multi‐year La Niñas but was zonally shifted during the first winter
The shifted pattern results from an unique pre‐onset Indian ocean condition of multi‐year La Niña and atmospheric teleconnections it excites
The different sea ice impacts revealed in the CESM1 simulation appear in four of the six observed multi‐year La Niña events during 1979–2020
In recent years, micrometer‐sized Si‐based anode materials have attracted intensive attention in the pursuit of energy‐storage systems with high energy and low cost. However, the significant volume ...variation during repeated electrochemical (de)alloying processes will seriously damage the bulk structure of SiOx microparticles, resulting in rapid performance fade. This work proposes to address the challenge by preparing in situ magnesium‐doped SiOx (SiMgyOx) microparticles with stable structural evolution against Li uptake/release. The homogeneous distribution of magnesium silicate in SiMgyOx contributes to building a bonding network inside the particle so that it raises the modulus of lithiated state and restrains the internal cracks due to electrochemical agglomeration of nano‐Si. The prepared micrometer‐sized SiMgyOx anode shows high reversible capacities, stable cycling performance, and low electrode expansion at high areal mass loading. A 21700 cylindrical‐type cell based on the SiMgyOx‐graphite anode and LiNi0.8Co0.15Al0.05O2 cathode demonstrates a 1000‐cycle operation life using industry‐recognized electrochemical test procedures, which meets the practical storage requirements for consumer electronics and electric vehicles. This work provides insights on the reasonable structural design of micrometer‐sized alloying anode materials toward realization of high‐performance Li‐ion batteries.
The in situ element doping approach developed in this research provides not only a promising material (SiMgyOx) as high‐performance Li‐ion battery anodes with superior properties and low industrialization cost for commercial applications, but also insights on the reasonable structural design of micrometer‐sized alloying anode materials for restraining internal cracks and improving electrochemical performance.
Distributed flow shop scheduling of a camshaft machining is an important optimization problem in the automobile industry. The previous studies on distributed flow shop scheduling problem mainly ...emphasized homogeneous factories (shop types are identical from factory to factory) and economic criterion (e.g., makespan and tardiness). Nevertheless, heterogeneous factories (shop types are varied in different factories) and environment criterion (e.g., energy consumption and carbon emission) are inevitable because of the requirement of practical production and life. In this article, we address this energy-efficient scheduling of distributed flow shop with heterogeneous factories for the first time, where contains permutation and hybrid flow shops. First, a new mathematical model of this problem with objectives of minimization makespan and total energy consumption is formulated. Then, a hybrid multiobjective optimization algorithm, which integrates the iterated greedy (IG) and an efficient local search, is designed to provide a set of tradeoff solutions for this problem. Furthermore, the parameter setting of the proposed algorithm is calibrated by using a Taguchi approach of design-of-experiment. Finally, to verify the effectiveness of the proposed algorithm, it is compared against other well-known multiobjective optimization algorithms including MOEA/D, NSGA-II, MMOIG, SPEA2, AdaW, and MO-LR in an automobile plant of China. Experimental results demonstrate that the proposed algorithm outperforms these six state-of-the-art multiobjective optimization algorithms in this real-world instance.
This study finds the seasonal footprinting (SF) mechanism to be a key source of El Niño–Southern Oscillation (ENSO) complexity, whereas the charged‐discharged (CD) mechanism acts to reduce ...complexity. The CD mechanism forces El Niño and La Niña to follow each other, resulting in a more cyclic and less complex ENSO evolution, while the SF mechanism involves subtropical forcing and results in an ENSO evolution that is more episodic and irregular. The SF mechanism also has a tendency to produce multiyear La Niña events but not multiyear El Niño events, contributing to El Niño‐La Niña asymmetries. The strength of CD mechanism has been steady, but SF mechanism has intensified during the past two decades, making ENSO more complicated. Most Climate Model Intercomparison Project version 5 models overestimate the strength of the CD mechanism but underestimate the strength of the SF mechanism, causing their simulated ENSOs to be too regular and symmetric.
Plain Language Summary
El Niño–Southern Oscillation (ENSO) is known to have profound climate impacts worldwide, but the causes of its complex behaviors are still not fully understood. In this study, we show that the subtropical atmosphere‐ocean coupled forcing is a key source of ENSO complexity, whereas the tropical ocean heat content variation acts to reduce ENSO complexity. The subtropical forcing also has a tendency to produce multiyear La Niña events but not multiyear El Niño events, contributing to El Niño‐La Niña asymmetries. In contrast to the steady strength of the tropical variation throughout the past six decades, the strength of the subtropical forcing has increased since the early 1990s. This may have made ENSO more complex recently and, if this trend does not reverse, possibly into the coming decades. Contemporary climate models overestimate the strength of the tropical ocean heat content variation but underestimate the strength of the subtropical forcing, which may be a reason why contemporary models produce ENSO behavior that is too regular.
Key Points
The seasonal footprinting (SF) mechanism is a key to ENSO complexity and asymmetry, but the charged‐discharged (CD) mechanism reduces them
The CMIP5 models overestimate (underestimate) the strength of the CD (SF) mechanism, causing their simulated ENSOs to be too regular
The strength of CD mechanism has been steady, but SF mechanism has intensified during the past two decades, making ENSO more complicated
Aqueous Zn batteries have drawn tremendous attention for their several advantages. However, the challenges of Zn anodes such as the corrosion and ZnO densification have compromised their application ...in rechargeable Zn‐based batteries. In this paper, a straightforward strategy is employed to facilitate the uniform Zn stripping/plating of the Zn anode through using a ZrO2 coating layer, which contributes to the controllable nucleation sites for Zn2+ and fast Zn2+ transportation through the favorable Maxwell–Wagner polarization. As a result, the low polarization (24 mV at 0.25 mA cm−2), high Coulombic efficiency (99.36% at 20 mA cm−2), and long cycle life (over 3800 h at 0.25 mA cm−2) can be obtained for the ZrO2‐coated Zn anode. It is believed that the ZrO2 coating layer can also act as an inert physical barrier to decrease the contact of the anode and electrolyte, thus reducing both the Zn corrosion and formation of ZnO densification, and then improve the reversibility of Zn anode. The results demonstrated in this work provide an appealing strategy for the future development of rechargeable Zn‐based batteries.
A highly reversible Zn anode is achieved through controllable nucleation sites for Zn2+ and fast Zn2+ transportation under the favorable Maxwell–Wagner polarization, in which a low polarization (24 mV), high Coulombic efficiency (99.36%), and long cycle life (over 3800 h) are obtained by employing a ZrO2‐coating layer.
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