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Strong gravitational lensing is a powerful tool for investigating dark matter and dark energy properties. With the advent of large-scale sky surveys, we can discover strong-lensing systems on an unprecedented scale, which requires efficient tools to extract them from billions of astronomical objects. The existing mainstream lens-finding tools are based on machine-learning algorithms and applied to cutout-centered galaxies. However, according to the design and survey strategy of optical surveys by the China Space Station Telescope (CSST), preparing cutouts with multiple bands requires considerable efforts. To overcome these challenges, we have developed a framework based on a hierarchical visual transformer with a sliding window technique to search for strong-lensing systems within entire images. Moreover, given that multicolor images of strong-lensing systems can provide insights into their physical characteristics, our framework is specifically crafted to identify strong-lensing systems in images with any number of channels. As evaluated using CSST mock data based on a semianalytic model named CosmoDC2, our framework achieves precision and recall rates of 0.98 and 0.90, respectively. To evaluate the effectiveness of our method in real observations, we have applied it to a subset of images from the DESI Legacy Imaging Surveys and media images from Euclid Early Release Observations. A total of 61 new strong-lensing system candidates are discovered by our method. However, we also identified false positives arising primarily from the simplified galaxy morphology assumptions within the simulation. This underscores the practical limitations of our approach while simultaneously highlighting potential avenues for future improvements.

Variations of the North American summer monsoon (NASM) and North Atlantic tropical cyclone (NATC) activities strongly influence climate anomalies in North America, with serious potential risk to life and property. Despite the scientific importance of this topic, the possible linkage between the NASM and the NATC genesis frequency remains unexplored. Here, we aim to examine the relationship between interannual variations of the NASM intensity and the NATC genesis frequency based on observations and Coupled Model Intercomparison Project Phase 6 (CMIP6) models. Our results show a strong association between the NASM intensity and the NATC genesis frequency during the extended boreal summer, with a good synchronization between their interannual variations. In years with stronger (weaker) NASM intensity, the NATC genesis frequency tends to be higher (lower). The observed NASM–NATC synchronization may be explained by two pathways: tropical-ocean-driven pathway and monsoon-heating-driven pathway. In the tropical-ocean-driven pathway, the tropical Pacific and Atlantic interbasin sea surface temperature (SST) anomalies play a critical role in bridging the NASM and NATC, by modulating the cross-Central American wind. Simulations of the tropical Pacific–Atlantic interbasin SST anomalies are critical for CMIP6 models to capture the observed linkage between the NASM and the vertical wind shear over the NATC main development region (MDR). In the monsoon-heating-driven pathway, the heating source due to the rainfall anomalies associated with the NASM can trigger atmospheric circulation anomalies through the Gill-type response, thereby affecting the NATC by changing the vertical wind shear over the MDR. This study demonstrates a connection between interannual variations of the NASM and the NATC genesis frequency, results of which can be used to advance our understanding of the monsoon–TC relationship and increase research focus on the interannual NASM–NATC synchronization in climate prediction.

The South Asian summer monsoon (SASM) exerts a profound influence on South Asia and the southern Tibetan Plateau. The timing of its onset and withdrawal significantly impacts regional rainfall, a critical water source for agriculture and the economy. Various SASM indices, employing different variables, have been employed to gauge monsoon onset and withdrawal, each demonstrating distinct characteristics. This study provides a comprehensive comparison of prominent SASM indices related to onset and withdrawal, revealing similar timing but varying magnitudes. Across nearly all indices, a consistent pattern emerges, indicating a trend towards earlier onset and delayed retreat during 1979–2018, marked by pronounced interdecadal variability, with a notable turning point around 1997. The earlier onset and later retreat are likely to enhance rainfall and potential water resources for South Asia and the Tibetan Plateau. Delving into the mechanisms revealed a delayed connection between the SASM onset to the large-scale sea surface temperature (SST) anomalies characterized by the Oceanic Niño Index (ONI) in the preceding spring, but a simultaneous connection between SASM withdrawl and ONI in autumn. Current index definitions, relying on single or dual variables, may fall short in accurately depicting monsoon onset and withdrawal. To address this, we introduce a novel monsoon index derived from multiple large-scale circulation variables, offering improved trend capture and enhanced representation of interannual variability in SASM onset and withdrawal. This study advances our understanding of SASM indices and their correlation with monsoon rainfall, providing insights into the dynamics of SASM onset and withdrawal.

3D printing stands at the forefront of transforming space exploration, offering unprecedented on-demand and rapid manufacturing capabilities. It adeptly addresses challenges such as mass reduction, intricate component fabrication, and resource constraints. Despite the obstacles posed by microgravity and extreme environments, continual advancements underscore the pivotal role of 3D printing in aerospace science. Beyond its primary function of producing space structures, 3D printing contributes significantly to progress in electronics, biomedicine, and resource optimization. This perspective delves into the technological advantages, environmental challenges, development status, and opportunities of 3D printing in space. Envisioning its crucial impact, we anticipate that 3D printing will unlock innovative solutions, reshape manufacturing practices, and foster self-sufficiency in future space endeavors.

To observe meteorite ablation, simulation experiments were conducted on the L5 ordinary chondrite and IAB-MG iron meteorites in an arc-heated facility and three flight conditions were reproduced. To mimic the high heating rates and the significant shear stress that meteorites experience during Earth entry, the samples were machined into 9° spherical cones with a 20 mm nose radius. High-quality video, the surface temperature, a time-resolved spectrum, and infrared video were recorded. The atom species were determined via spectroscopy to analyze the ablation products. Due to the electrode erosion and dissociation of air, the atomic lines of copper, nitrogen, and oxygen were detected in all the tests. Although the copper atom is a pollutant to the flow field, the five copper lines were used to determine the flow-field temperature. The ablation rates and effective heat of ablation of both the samples were measured under different conditions. The results indicate that shear stress is the dominant factor influencing meteorite ablation. Furthermore, the diversity between stony and iron meteorites suggests that the mass loss of stony meteorites depends on the fragmentation of the main body and that of iron meteorites depends on the shearing loss of the molten layer. Then, the fusion crusts were analyzed, the microstructures of the samples were obtained, the crust thicknesses were measured, and the elemental distribution of the stony meteorites was determined via energy dispersion spectroscopy. The study results explain the differences in the ablation and recrystallization process between stony and iron meteorites.

The James Webb Space Telescope (JWST) marks a new era of astronomical observation and discovery, providing unrivaled precision in various measurements, including photometry, morphology, and shear measurement. Accurate point-spread function (PSF) models are essential for many of these measurements. In this paper, we introduce HybPSF, a hybrid PSF construction method for JWST NIRCam imaging data that combines the WebbPSF software, which simulates the PSF for JWST, with observed data to produce more accurate and reliable PSF models. We apply this method to the SMACS J0723 imaging data and construct supplementary structures from residuals obtained by subtracting the WebbPSF PSF model from the data. Our results show that HybPSF significantly reduces discrepancies between the PSF model and the data compared to WebbPSF. Specifically, the PSF shape parameter ellipticity and size comparisons indicate that HybPSF improves precision by approximately 10 times for R ^2 and 50% for e . This improvement has important implications for astronomical measurements using JWST NIRCam imaging data.

Magnetic field signatures over impact craters provide constraints for the history of the Martian dynamo. Due to limitations of the spatial resolution of magnetic field models, previous studies primarily focused on large impact craters (mostly ≥ 500 km in diameter). To fill the impact crater age gaps of previous studies, we investigate the magnetic field signature of 23 intermediate-sized craters (150–500 km in diameter) on Mars using both MAVEN data and a magnetic field model. Ten impact craters located in the South Province, the unmagnetized primordial crust, exhibit no or weak magnetic field signatures. The other 13 impact craters produce stronger magnetic anomalies, with the ratio of the averaged magnetic field inside and outside the craters ( B _in / B _out ) ranging from 0.4 to 1.2. The B _in / B _out values exhibit correlation coefficients of −0.54, −0.57, and −0.69 with the diameters of craters, calculated from the MAVEN data, the crustal field model at the surface, and 150 km altitude, respectively. A B _in / B _out larger than 1.0 usually appears in craters with smaller diameters, which is also demonstrated by the forward modeling in this study. Furthermore, the results of the forward modeling indicate that the craters of stronger magnetizations show a larger B _in / B _out . According to this, the Martian dynamo can be associated with the magnetization of craters of different ages, and the characteristic time of the dynamo can be limited. Our study supports the hypothesis that the Martian dynamo weakened or ceased at ∼4.0 Ga and a late dynamo was perhaps active at ∼3.7 Ga.

Classical El Niño–Southern Oscillation (ENSO) theories mainly consider the vertical process-related Ekman and thermocline feedbacks. However, the zonal current-related zonal advective feedback has been suggested to play a crucial role in the evolution of central Pacific (CP) El Niño and La Niña events. Also, the simulation of a realistic current is complex and not the focus of the classical ENSO theories. Using reanalysis datasets and a statistical model, this study emphasizes the importance of the zonal currents in the sea surface temperature anomaly (SSTA) evolution in the Niño4 region (160° E–150° W, 5° S–5° N). Specifically, in addition to the widely used predictors for the ENSO evolution, i.e. the equatorial Pacific mean thermocline depth anomaly (D20) and the zonal wind stress anomaly (ZWS), the zonal current anomaly (ZCA) averaged in the CP is first extracted to construct a statistical model to predict the SSTA of the Niño4 region. The results show that this model has improved overall prediction skill and accuracy for several CP El Niño and La Niña events during 1980–2020, compared with the benchmark linear regression model based on D20 and ZWS. By further removing the components related to the equatorial Kelvin and first symmetric meridional ( $m = 1$ ) Rossby waves (namely, the principal part of the traditional ENSO mechanism) from the ZCA, the remainder, which contains higher-order Rossby waves and other nonlinear components and is called the zonal current anomaly residual (ZCA_RSD), is found to be the key part of the improvements in the prediction skill. This suggests that to better simulate and predict the complex ENSO events, more vertical and meridional modes of the tropical Pacific need to be included to obtain a realistic anomalous zonal current.

Stationary waves are time-averaged zonally asymmetric component of the climatological mean atmospheric circulation, primarily due to the unevenly distributed topography and diabatic heating. Stationary waves are subject to influence from long-term external forcing. In this study, the temporal evolution of the winter (January) Northern Hemisphere stationary waves during 1961–2020 is diagnosed with the fifth generation European Centre for Medium-range Weather Forecasts reanalysis data (ERA5), which shows an overall strengthening in amplitude and an eastward shift in phase. A stationary wave model is used to attribute the stationary wave response to changes in the zonal mean basic state (Δ ZM ) and the zonally asymmetric diabatic heating forcing ( $\Delta {q^*}$ ). The pattern of stationary wave changes is well captured by the response to Δ ZM alone, whereas the contribution of $\Delta {q^*}$ to the amplitude increases in height and becomes dominant in the stratosphere. $\Delta {q^*}$ is also found to be important in driving stationary wave changes in the North Pacific and Western Europe regions. Furthermore, changes in tropospheric stationary waves are probably a result of internal variability, whereas stratospheric changes are more likely to be driven by external forcing.

Global warming accelerates the rate of inter-regional hydrological cycles, leading to a significant increase in the frequency and intensity of hydrological wet extremes. The Tibetan Plateau (TP) has been experiencing a rapid warming and wetting trend for decades. This trend is especially strong for the upper Brahmaputra basin (UBB) in the southern TP. The UBB is the largest river on the TP, and these changes are likely to impact the water security of local and downstream inhabitants. This study explores the spatial-temporal variability of wet extremes in the UBB from 1981–2019 using a water- and energy-budget distributed hydrological model (WEB-DHM) to simulate river discharge. The simulated results were validated against observed discharge from the Ministry of Water Resources at a mid-stream location and our observations downstream. The major findings are as follows: (1) the WEB-DHM model adequately describes land-atmosphere interactions (slight underestimation of −0.26 K in simulated annual mean land surface temperature) and can accurately reproduce daily and monthly discharge (Nash-Sutcliffe efficiency is 0.662 and 0.796 respectively for Nuxia station); (2) although extreme discharge generally occurs in July and is concentrated in the southeastern TP, extreme wet events in the UBB are becoming increasingly frequent (after 1998, the number of extreme days per year increased by 13% compared to before) and intense (maximum daily discharge increased with a significant trend of 444 (m ^3 s ^−1 ) yr ^−1 ), and are occurring across a wider region; (3) Precipitation is more likely to affect the intensity and spatial distribution of wet extremes, while the air temperature is more correlated with the frequency. Our wet extreme analysis in the UBB provides valuable insight into strategies to manage regional water resources and prevent hydrological disasters.

Carbon dioxide (CO _2 ) and methane (CH _4 ) emissions from freshwater ecosystems are predicted to increase under climate warming. However, freshwater ecosystems in glacierized regions differ critically from those in non-glacierized regions. The potential emissions of CO _2 and CH _4 from glacierized environments in the Tibetan Plateau (TP) were only recently recognized. Here, the first direct measurement of CO _2 and CH _4 emission fluxes and isotopic composition during the spring of 2022 in 13 glacial lakes of the TP revealed that glacial lakes were the previously overlooked CO _2 sinks due to chemical weathering in glacierized regions. The daily average CO _2 flux was −5.1 ± 4.4 mmol m ^−2 d ^−1 , and the CO _2 consumption could reach 38.9 Gg C-CO _2 yr ^−1 by all glacial lakes in the TP. This consumption might be larger during summer when glaciers experience intensive melting, highlighting the importance of CO _2 uptake by glacial lakes on the global carbon cycle. However, the studied glacial lakes were CH _4 sources with total emission flux ranging from 4.4 ± 3.3 to 4082.5 ± 795.6 μ mol m ^−2 d ^−1 . The large CH _4 range was attributed to ebullition found in three of the glacial lakes. Low dissolved organic carbon concentrations and CH _4 oxidation might be responsible for the low CH _4 diffusive fluxes of glacial lakes without ebullition. In addition, groundwater input could alter CO _2 and CH _4 emissions from glacial lakes. CH _4 in glacial lakes probably had a thermogenic source; whereas CO _2 was influenced mainly by atmospheric input, as well as organic matter remineralization and CH _4 oxidation. Overall, glacial lakes in the TP play an important role in the global carbon cycle and budget, and more detailed isotopic and microbial studies are needed to constrain the contributions of different pathways to CO _2 and CH _4 production, consumption and emissions.

Magnetic reconnection between neighboring magnetic field loops, the so-called interloop reconnection, is a common process to drive flares in the solar atmosphere. However, there is no direct evidence that a similar but less explosive process can take place on planets. The strong crustal fields on Mars generate plenty of magnetic loops in the near-Mars regions, providing a unique environment to research the interloop reconnection on a planet. Here, we report magnetic reconnection events between crustal field loops in the Martian ionosphere observed by Mars Atmosphere and Volatile EvolutioN (MAVEN) for the first time. During the current layer crossing, MAVEN recorded the characteristic signals of collisionless magnetic reconnection, including the Hall magnetic field, Alfvénic outflow, and electron energization. This finding implies that the interloop reconnection in the Martian ionosphere could contribute to the localized energy deposition and particle energization, which provides the seed source for aurora in the Martian atmosphere.

The large-scale circulation, Indian summer monsoon (ISM), has a strong influence on the Tibetan Plateau (TP) since its onset and intensity have profound impacts on regional precipitation, which then can supply water for glaciers, lakes, rivers and social demands. Weakening monsoon intensity and longer monsoon duration seem contradictory, as a weaker monsoon tends to produce less precipitation, while a longer duration increases the probability of precipitation. Past research has focused on how ISM’s intensity affects precipitation, with little consideration of the impacts of ISM duration. Here, we investigate the long-term (1979–2100) variability in the ISM’s duration and intensity. We find a prolonged ISM from 1979 to 2018, accompanied by monsoon weakening. Different combinations of duration and intensity have resulted in different spatial patterns of precipitation across the southeastern TP. Weakening and prolonged ISM is helpful to produce more precipitation around the southeastern TP, with intensity acting as a dominant control. Afterwards, an obvious impact can be found on potential water availability. Climate projections suggest that the ISM will weaken and lengthen until 2100, thereby increasing precipitation and potential water availability across the southeastern TP. This long-term trend should receive more attentions as increased regional extreme precipitation will increase the probability of flood risks until the end of this century.

Kelvin–Helmholtz (K-H) instability is a fundamental boundary instability between two fluids with different speeds, exchanging the mass, momentum, and energy across the boundary. Although the K-H instability has been suggested to play a critical role in atmospheric ion loss on Mars, the knowledge about its formation and evolution is still poor, due to the limitation of spacecraft missions and a dearth of dedicated simulation codes. In this study, we combine observations from the Mars Atmosphere and Volatile EvolutioN mission and global 3D kinetic simulations to investigate the solar wind–Mars interaction. For the first time, it is found that K-H waves prominently appear in the −E hemisphere, which is attributed to the stronger proton velocity shear therein associated with the asymmetric diamagnetic drift motion of protons. The K-H instability is mainly excited in the −E hemisphere and propagates downstream along the boundary, with the waves also able to be generated near the subsolar point. The K-H waves produce plasma clouds with a net oxygen ion escape rate of about 1.5 × 10 ^24 s ^−1 , contributing to almost half of the global loss on present-day Mars. This heavy ion escape pattern associated with K-H instability is cyclic and could occur on other nonmagnetized planets, potentially influencing planetary atmosphere evolution and habitability.

Seasonal variation of the Indo-Pacific warm pool (IPWP) plays an important role in oceanographic and climatological processes. While expansion of the IPWP under greenhouse warming has been widely discussed, the response of IPWP seasonality to climate change has received limited attention. In this study, we found an obvious seasonal diversity in expansion of the IPWP from 1950 to 2020, with a maximum (minimum) expansion trend of 0.28 $ \times $ 10 ^7 km ^2 /decade in winter (0.17 $ \times $ 10 ^7 km ^2 /decade in spring), which consequently reduces the seasonality amplitude of the variation in IPWP size. This is primarily attributed to the seasonal difference in the climatological spatial sea surface temperature (SST) pattern over the Indo-Pacific Ocean, especially that over the tropical Indian Ocean, which determines the capacity for IPWP expansion. Heat budget analyses show that the seasonal shortwave radiation and latent heat fluxes are the major factors controlling the capacity for change in IPWP size across seasons. The presented analyses emphasize the significant weakening of the seasonality of IPWP size, which may have great impacts on the ecological environment of the IPWP and the tropical climate system, and remind us that the intrinsic properties of the climate background of Indo-Pacific SST hold important clues about IPWP expansion under climate change.

In this paper, a novel strategy was used to grow CeO _2 /Ce(OH)CO _3 composite in situ by the incomplete conversion of CeO _2 to Ce(OH)CO _3 using ethylene glycol (EG) as CO _3 ^2− source and solvent. Interestingly, the content of Ce(OH)CO _3 in CeO _2 /Ce(OH)CO _3 composite can be controlled by changing the solvent composition. The obtained CeO _2 /Ce(OH)CO _3 composite all exhibited enhanced photocatalytic performance for methylene blue (MB) degradation. The CeO _2 /Ce(OH)CO _3 composite prepared at 200 °C for 24 h with a H _2 O/EG volume ratio of 0.5 showed the best visible-light activity with a degradation efficiency of 98.84% within 120 min. This work provided a novel method to fabricate basic rare Earth carbonates and their composites for environmental purification.

The causality between Arctic sea ice decline and cold boreal winters has been widely debated recently and remains controversial. A major source of uncertainty in the sea ice-cold winter relationship originates from that the stratosphere polar vortex (SPV) is not only affected by Arctic sea ice anomaly but can also be modulated by El Niño-Southern Oscillation (ENSO) and quasi-biennial oscillation (QBO). Using reanalysis data and hindcasts from the decadal prediction system version 4, here we show that both cold and warm winters occur over Eurasia when the Barents–Kara Sea sea ice is abnormally low. Warm winters occur during the La Niña-easterly QBO-low sea ice (LANINA-EQBO-LICE) years and cold winters during the neutral ENSO-neutral QBO (NENSO-NQBO)-LICE and El Niño (ELNINO)-NQBO-LICE years. During the LANINA-EQBO-LICE years, weakened upward-propagating planetary waves from the troposphere to the stratosphere strengthen the Arctic SPV and then weaken the Aleutian low and Siberian high, creating conditions favorable for Eurasian warming. The atmospheric responses are opposite in the NENSO-NQBO-LICE and ELNINO-NQBO-LICE years. This implies that care should be taken in using Arctic sea ice alone as the precursor to predict boreal winter climate.

Since the 20th century, due to global warming, permafrost areas have undergone significant changes. The degradation of permafrost has complicated water cycle processes. Taking the upper Yellow River basin (UYRB) as a demonstration, this study discusses the long-term (1960–2019) changes in frozen ground and their hydrological effects with a cryosphere-hydrology model, in particular a permafrost version of the water and energy budget-based distributed hydrological model. The permafrost at the UYRB, with thickening active layer and lengthening thawing duration, has degraded by 10.8%. The seasonally frozen ground has a more pronounced intra-annual regulation that replenishes surface runoff in the warm season, while the degradation of permafrost leads to a runoff increase. The occurrence of extreme events at the UYRB has gradually decreased with the degradation of frozen ground, but spring droughts and autumn floods become more serious. The results may help better understand the hydrological impacts of permafrost degradation in the Tibetan Plateau.

Flooding in the Yangtze River Basin could severely damage socio-economic development, river ecosystems, food security, hydropower production and transportation in China. The Yangtze River Basin accounts for approximately 30% of China’s gross domestic product (GDP) and is an engine for the country’s rapid economic growth. One commonly held belief is that climate change has intensified extreme flood events, leading to increasing economic damage in the Yangtze River. Here, we quantitatively attributed economic exposure to climate change (i.e. climate-induced changes in weather-related events) and GDP growth, and assessed benefits, i.e. the reduction in economic exposure, from flood defence dikes of varying heights. To do this, we developed a framework by combing a large scale hydrological model, a hydraulic model, and long-term GDP data. We find that climate-induced changes in flood inundation area and resulted economic exposure were decreasing overall, whereas GDP growth drove the increases of potential economic exposure to floods. We also reveal that the basin average flood defence dikes should be at least approximately 3.5 m high to achieve an about ten-year average flood occurrence. Our results have significant policy and socioeconomic development implications.

In this study, the synergistic effects of Y and Nd on the grain refinement of the as-cast Mg-Y-Nd-Al alloy was investigated by varying Y and Nd contents while fixing their total content (Y + Nd) at 7%. When the contents of Y and Nd were 3% and 4%, respectively, the refinement was most effective and the smallest grain size of 49 ± 5 μ m was achieved. The grain refinement process was primarily controlled by the heterogeneous nucleation and the growth restriction factor (Q value). Y could only form Al _2 RE phase with Al, while both Al _2 RE and Al _11 RE _3 were formed between Nd and Al. The Al _2 RE phase acted as nucleation particles of α -Mg and facilitated heterogeneous nucleation; however, Al _11 RE _3 was an unfavorable phase for heterogeneous nucleation. When the Y content was less than 3%, the quantity of Al _2 RE phase increased when more Y was available, which resulted in more active nucleation particles and better refinement. When the Y content exceeded 3%, the Q value (growth limiting factor) of the alloy decreased, while the quantity of Al _2 RE phase remained unchanged. This would lead to a decreased number of active nucleation particles and a less effective grain refinement.

Tropical cyclone precipitation (TCP) has increasing impacts on many coastal regions under global warming. Causes of TCP variation have been principally explored in the troposphere. This study identifies the significant modulation of the stratosphere Quasi-Biennial oscillation (QBO) on the winter TCP in the coastal regions of the western North Pacific (WNP). In the westerly QBO winter, the zonal wind vertical shear anomalies in the stratosphere strengthen (weaken) convective activities around the East China Sea (the Philippines) and cause middle-level easterly (westerly) anomalies of the middle (low) latitudes in the troposphere, leading to more (less) TC activities around the East China Sea (the Philippines). Consequently, a TCP dipole pattern can be observed. The TCP increases in East China, Korean peninsula, Japan and Russian Far East, but decreases in Indo–China Peninsula, South China and the Philippines. These results not only improve the knowledge of QBO-TCP relationship but also provide a potential indicator for the seasonal prediction of the TCP in the coastal regions of the WNP due to the high predictability of the QBO.

Understanding the variation in reference evapotranspiration (ET _o ) is vital for hydrological cycles, drought monitoring, and water resource management. With 1507 meteorological stations and 130 radiation-measured stations, the annual and seasonal ET _o were calculated at each site from 1960 to 2016 in mainland China. The phenomenon of coefficient ‘ a ’ being less than 0.25 and coefficient ‘ b ’ being greater than 0.50 in the Angstrom–Prescott model occurred in almost the whole country, except for a small area of western and northeastern China. Moreover, the Xiao’s method was more applicable to calculate the net longwave radiation ( R _nl ) and then improve the estimation accuracy of ET _o . The annual ET _o varied from 538.8 to 1559.8 mm and had a high-value center located in the plateau and desert of northwestern China and a low-value center located in Northeast China and near the Sichuan Basin. The spatial distribution of seasonal ET _o was roughly similar to that of annual ET _o , except for that in winter when ET _o was high in the south and low in the north. In mainland China, the annual ET _o decreased by 21.2 mm decade ^−1 because of the declining sunshine duration before 1993 and increased by 21.1 mm decade ^−1 due to the decreased relative humidity (RH) after 1993. Generally, the abrupt change of ET _o mainly occurred in the southern China rather than northern China (except for Qinghai Tibet Plateau). Basically, the dominant driving factors of annual and seasonal ET _o were RH and/or T _max after the abrupt change in most parts of China.

Recent studies have shown arguments about the connection between stratospheric quasi‐biennial oscillation (QBO) and activities of Madden‐Julian oscillation (MJO) during boreal winter on interannual timescale, especially for the question of which aspects of MJO, amplitude or occurrence frequency, can really be modulated by QBO. This study re-examines the interannual variability of the seasonally averaged amplitude and the occurrence of both ‘active’ (amplitude > 1.0) and ‘inactive’ (amplitude < 1.0) MJO days in boreal winter December–January–February (DJF), and their relation to QBO variation. Significant correlations between the QBO index and the indicators of MJO activity reveal that wintertime amplitude of ‘active’ and ‘inactive’ MJO days are typically larger in QBO easterly phase (EQBO) than in QBO westerly phase (WQBO). More importantly, we can also expect more ‘active’ MJO days and simultaneously less ‘inactive’ MJO days in EQBO winter as a consequence of more days in winter shifting from ‘inactive’ to ‘active’ due to larger MJO amplitudes. The significantly positive (negative) correlation between the time series of averaged amplitude and occurrence of ‘active’ (‘inactive’) MJO days can as well be interpreted as evidence that QBO is closely connected to the occurrence of MJO days via modulating MJO amplitudes. These results update our current understanding of the QBO-MJO connection, which is helpful to advance the MJO prediction.

In this study, the flame aerosol synthesis (FAS) method was used to synthesize a yttrium aluminum garnet (Y _3 Al _5 O _12 , YAG) nanopowder. The dominant reaction route in the FAS method is the liquid route; this shaped the primary morphology of the YAG nanopowder into hollow and solid spheres. The effects of precursor concentration and annealing parameters were systematically investigated. At a precursor concentration of 0.4 mol L ^−1 and an annealing temperature of 1400 °C, the YAG nanopowder exhibited excellent infrared transmittance. Compared to other conventional synthesis methods, the FAS method has the advantages of high yield, low cost, and ease of obtaining a nanosized powder. The FAS method is thought to be one of the best choices for the large-scale production of YAG powders.

Metakaolin-based auxiliary cementitious materials fabricated by coal gangue were achieved. The temperature and time required for the preparation of metakaolin materials from the calcination of coal gangue were optimized based on the analysis of the reaction characteristics and kinetics during the calcination of coal gangue. The phase, microstructures, and activity analysis of the products were performed, and the effect of calcination conditions on the activity of the product was ascertained. The results of thermal analysis-infrared spectra combined experiments indicated that the dehydroxylation of kaolinite was a one-step reaction during the calcination of coal gangue within a temperature range of 379.8 °C–737.3 °C. According to the General Integration, Flynn-Wall-Ozawa and Kissinger methods, the activation energy E of dehydroxylation of kaolinite is 181.62 kJ·mol ^−1 and pre-index factor A is 10 ^9.27 s ^−1 for calculating the calcination time of metakaolin. The experimental results show that high-activity metakaolin products, that with a dissolution rate of 64.79–71.57 wt% of activated alumina and with an effective dissolution rate of 68.82–94.35 wt% of activated silica, are prepared under the condition of calcination for 15 min and the temperature of 700 °C–825 °C. The kinetic model simulation results for the calcination time at different temperatures correspond to the experimental results.

Gadolinium aluminate (GdAlO _3 , GAP) is a rare earth compound with perovskite structure. Its optical isotropic structure prevents the defects of refractive index difference in any direction. GAP has unique and excellent properties in electricity, magnetism, luminescence and catalysis, especially as a high-quality luminescent matrix material. Sol-gel method has the advantages of accurate control of chemical composition, particle size and purity of products. The main preparation parameters include chelating agent concentration, alcohol water ratio, calcination temperature and so on. In this paper, the citric acid chelating agent was used to prepare gadolinium aluminate nanoparticles by sol-gel method, thermogravimetry-differential thermal analysis (TG-DTA), x-ray diffraction (XRD) and scanning electron microscope (SEM) were employed to analyze the effects of chelating agent, dispersant, solvent and calcination temperature on the phase and morphology changing in precursor and final product. The results show that GAP nanoparticles with high degree of crystallinity, nearly spherical morphology and 60–100 nm particle size can be obtained at the molar ratio of citric acid to cationic of 1:1, the ammonium citrate to citric acid of 1.5:1 and the calcination temperature of 900 °C for 4 h. When the calcination temperature is higher than 1100 °C, a new phase of Gd _3 Al _5 O _12 (GdAG) will be formed with calcination neck shape.

In addition to providing basic protective functions, modern military uniforms are also being designed to provide special functions, such as infrared shielding. In this study, a nanoscale copper film was deposited on Kevlar para-1414 aramid fabric by magnetron sputtering technology to significantly enhance infrared shielding. The deposition of a uniform nano-copper film on the surface of the aramid fabric enhanced infrared shielding, tensile strain, and conductivity, which is of guiding significance for the development of infrared shielding garments.

The effects of pretreatment and homogenization on the microstructure of a new Al-6.7Zn-2.6Mg-2.0Cu-0.1Zr-0.3Sm alloy were investigated. The results show that severe dendritic segregation is visible at the grain boundaries of the as-cast microstructure, which consists of the η (Mg (Zn, Cu, Al) _2 ), Al _10 Cu _7 Sm _2 and Fe-rich phases. Besides, some small η and needle-shaped θ (Al _2 Cu) phases are distributed inside of the grains. After pretreatment at 400 °C for 10 h, the η phase and θ phase in the grains are dissolved, and Al _3 Zr particles are precipitated inside of the grains by homogeneous nucleation. However, dendritic segregation still exists at the grain boundaries. After homogenization annealing, the η phase present at the grain boundaries completely dissolves, and only a small number of Al _10 Cu _7 Sm _2 and Fe-rich phases remain. The alloy microstructure becomes more uniform and the volume fraction of residual eutectic decreases to 0.70% after homogenization annealing. The optimal homogenization processing is determined as 400 °C/10 h + 470 °C/24 h, which is in perfect accordance with the results obtained via homogenizing kinetic analysis.

A novel magnetic nano-zeolite (MNZ@MS) is successfully synthesized, characterized and applied to adsorp heavy metals from solution. In the synthesis of MNZ@MS, the fly ash magnetic sphere (MS) and [C _18 H _37 (CH _3 ) _2 -N ^+ -(CH _2 ) _3 -N ^+ -(CH _3 ) _2 C _18 H _37 ] Cl _2 is used as carrier and directing agent, respectively. The characterization results of XRD, XRF, XPS and SEM demonstrate that the nano-scale (200–600 nm) Linde F(K) zeolite completely wraps the magnetic spherical fly ash particle, and the saturation magnetization value of MNZ@MS is around 17.7 emu g ^−1 . MNZ@MS exhibits a favorable and efficient adsorption performances on heavy metals, and the maximum adsorption capacity of Cu, Cd and Pb on MNZ@MS is 59.9 mg g ^−1 , 188 .6 mg g ^−1 and 909.1 mg g ^−1 , respectively. The higher pH value in solution is more conducive to the adsorption process of heavy metals on MNZ@MS. The adsorption is a fast process, well represented by the pseudo-second-order model. Concerning the equilibrium behavior, Langmuir isotherm model are more suitable for describing the adsorption. Furthermore, in competitive adsorption system, the adsorption process of Pb is the most difficult to be interfered, and the order of adsorption advantage is Pb>Cu>Cd. MNZ@MS may be applied as a low-cost and efficient magnetic adsorbent for wastewater treatment to remove heavy metals.

Temperate forests regrowing from historical land use and land cover change in the eastern US serve as carbon (C) sinks. Environmental drivers have been significantly altered (e.g. rising atmospheric CO _2 concentration, warmer temperature, and elevated nitrogen (N) deposition) and will have a wide range of impacts on future forest C sinks. However, the interactions among these environmental drivers are unclear and their effects are subject to uncertainty. We assessed the combined and interactive effects of rising CO _2 concentration, climate change (temperature, precipitation), and N deposition on forest aboveground net primary production (ANPP) and their relative contribution to ANPP changes of a temperate forest in the eastern US. We used a process-based ecosystem model PnET-day to simulate coupled cycles of C, water, and N of forest ecosystems. We found that (1) climate change exerted negative effects on ANPP (−0.250 kg C m ^−2 yr ^−1 ) whereas rising CO _2 and N deposition enhanced ANPP (+0.253, +0.014 kg C m ^−2 yr ^−1 ); (2) climate change interacted with rising CO _2 and N deposition to decrease ANPP (−0.032, −0.018 kg C m ^−2 yr ^−1 ); rising CO _2 and N deposition acted in synergy to increase ANPP (+0.014 kg C m ^−2 yr ^−1 ); (3) changes in ANPP were mainly attributed to rising CO _2 and climate change whereas N deposition effects and any two- or three-factor interactive effects were relatively small. Our results suggest that the total negative effect sizes will not be offset by the total positive effect sizes, thus resulting in reductions in forest ANPP over the 21st century.

Leading indicators of future economic activity include measures such as new housing starts, managers purchasing index, money supply, and bond yields. Such macroeconomic and financial indicators hold predictive power in signaling recessionary periods. However, many indicators are constrained by the fact that data are often published with some delay and are subject to constant revision (Bandholz and Funke 2003 , Huang et al 2018 , Orphanides 2003 ). In this research, we propose a leading indicator derived from satellite imagery, the expansion of anthropogenic bare ground. Satellite-detected gain in built-up area, a major land cover and land use (LCLU) outcome of anthropogenic bare ground gain (ABGG), provides an inexpensive, consistent, and near-real-time indicator of global and regional macroeconomic change. Our panel data analysis across four major regions of the world from 2001 to 2012 shows that the logarithm of total ABGG, mostly owing to its major LCLU outcome, the expansion of built-up land in either year t , t −1 or t −2, significantly correlated with the year t logarithm of gross domestic product (GDP, de-trended by Hodrick–Prescott filter). Global ABGG between 2001 and 2012 averaged 7875 km ^2 yr ^−1 , with a peak gain of 11 875 (± 2014 km ^2 at the 95% confidence interval) in 2006, prior to the 2007–2008 global financial crisis. The curve of global ABGG or its major LCLU outcome of built-up area in year t − 1 accords well with that of the de-trended logarithm of the global GDP in year t . Given the 40 year archive of free satellite data, a growing satellite constellation, advances in machine learning, and scalable methods, this study suggests that analyses of ABGG as a whole or its LCLU outcomes can provide valuable information in near-real time for socioeconomic research, development planning, and economic forecasting.

Local thermal equilibrium (LTE) is a general presumption of many theoretical analyses in nonequilibrium statistical physics. It describes a situation that although the system is not in global thermal equilibrium, each small portion of the system may still be described approximately by the laws of thermal equilibrium. The validity of LTE has however seldom been investigated carefully. Here, by studying the ensemble velocity distribution and its spatial correlation, we present strong evidences for the lack of LTE in anomalous heat diffusion processes in one dimensional harmonic lattices and the Fermi–Pasta–Ulam- β lattices. In particular, clear nonzero excess kurtosis and long range correlations have been observed, with values scaling linearly with the initial temperature difference. Therefore near thermal equilibrium is not sufficient to achieve LTE. Some existing studies that are based on the existence of LTE should be revisited. Using the same methods, we also show that LTE is still valid in the ϕ ^4 lattice, in which heat diffuses following Fourier’s law.

Spinless fermions on a honeycomb lattice provide a minimal realization of lattice Dirac fermions. Repulsive interactions between nearest neighbors drive a quantum phase transition from a Dirac semimetal to a charge-density-wave state through a fermionic quantum critical point, where the coupling of the Ising order parameter to the Dirac fermions at low energy drastically affects the quantum critical behavior. Encouraged by a recent discovery (Huffman and Chandrasekharan 2014 Phys. Rev. B http://dx.doi.org/10.1103/PhysRevB.89.111101 89 http://dx.doi.org/10.1103/PhysRevB.89.111101 ) of the absence of the fermion sign problem in this model, we study the fermionic quantum critical point using the continuous-time quantum Monte Carlo method with a worm-sampling technique. We estimate the transition point $V/t=1.356(1)$ with the critical exponents $\nu =0.80(3)$ and $\eta =0.302(7)$ . Compatible results for the transition point are also obtained with infinite projected entangled-pair states.