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Ultralow dispersion gradient refractive index (GRIN) microlens arrays (MLAs) covering the visible to mid-infrared wavelength range are imprinted in GeS 2 -Ga 2 S 3 -CsI chalcohalide glass by an efficient and economical microthermal poling process. The effect of poling voltage on GRIN microstructure, structural rearrangement, optical properties of the poled glasses, and imaging of the imprinted MLAs have been investigated. Optical focal length of the GRIN MLAs decreases from 353 to 63 μm with increasing the poling voltage from 200 to 1000 V, which is in accordance with imprinting-induced phase difference increase from 0.57 λ to 1.19 λ. Optimal chromatic aberration (between 520 and 850 nm) as low as 5% is achieved in the GRIN MLAs. Formation mechanism of GRIN MLAs is mainly associated with an enhanced transverse migration of Cs+ ions within mesh square area, which is provided by an improved anode of microthermal poling setup. Thus, an efficient and inexpensive process developed can produce broadband and ultralow dispersion GRIN MLAs for imaging, display, and photovoltaic applications. [ABSTRACT FROM AUTHOR]

This work presents the influence of glass matrix SiO 2 –B 2 O 3 –NaF on the formation of near-infrared (NIR)-shielding functional units in energy-saving glass windows. The structural analyses by XRD, XPS, and Raman confirmed that the NIR-shielding performance is insensitive to SiO 2 or B 2 O 3 glass network formers but is significantly impacted by the concentration of NaF. This is because the presence of a reasonable amount of NaF provides the much-needed sodium for the formation of NIR-shielding functional units Na 5 W 14 O 44 but too much NaF (>22 mol.%) can inhibit the formation of Na 5 W 14 O 44 by transforming the W– O –W chain in the interconnected [WO 6 ] and [WO 4 ] polyhedrons into W–O- bonds. By adjusting NaF to the optimal level (16 mol.%) and adding only a small amount of H 2 WO 4 (1.9 mol.%) as the tungsten source in the raw materials, excellent optical properties and thermal insulation performance have been achieved in the produced bulk glass, with a high transmission of 65.8% at 550 nm in the visible light region and a low transmission of 6.6% at 1550 nm in the NIR region. This performance is much better than soda lime glass and ITO glass and is comparable to cesium tungsten bronze-based membrane coated glass. This study paves a way for glass composition design to achieve high NIR-shielding performance with the minimum amount of tungsten source, leading to cost-effective glass fabrication and enhanced mechanical strength of energy-saving glass windows. [ABSTRACT FROM AUTHOR]

NIR-shielding window materials were fabricated by direct embedding of Ta 0.3 W 0.7 O 2.85 nanocrystals in bulk borosilicate glass-ceramics during a facile melt-quenching process. Optical and thermal performance of the prepared windows can be adjusted by varying the concentration of H 2 WO 4 and Ta 2 O 5 in the starting materials. The optimized window fabricated from raw materials containing 4.5 mol% H 2 WO 4 and 0.3 mol% Ta 2 O 5 exhibited high visible light transmittance 74.4% and strong NIR-shielding ability ΔT = 68.9%. Its thermal insulation performance is much better than soda lime glass or ITO glass, and its visible light transmission is higher than cesium-tungsten-bronze-based film coated glass. The distribution of Ta 0.3 W 0.7 O 2.85 functional nanocrystals in the glass matrix was confirmed by sample characterization using XRD, Raman, XPS, HRTEM and EDS. The NIR-shielding property has been attributed to local surface plasmon resonance due to oxygen vacancies in the Ta 0.3 W 0.7 O 2.85 nanocrystals. This study sheds a light on fabricating energy-saving windows with a tunable NIR-shielding performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The mathematical model of CFD-DEM calculation method was used. • The inhale and dust exposure characteristics of driver were analyzed. • Different area airflow patterns of bronchus were analyzed. • The deposition rate of different particle diameters were analyzed. To study the dust exposure law of the operator in the anchor digging working face, the CFD-DEM method was used to numerically simulate the dust deposition pattern in the bronchus of the anchor digging driver. The results show that the highest dust concentration in the vortex region of the anchor digging working face can reach 2364.76 mg/m3, seriously endangering the health of anchor digging driver. The average dust concentration in the respiratory hemisphere of the driver is 510.57 mg/m3, and the range of inhaled dust diameter is 0–60 μm in the breathing state of moderate labour. Over time, the deposition mass in the bronchial showed a pattern of rapid and then slow increase, which was consistent with the trend of the Boltzmann model. Increasing dust particle diameter was positively correlated with bronchial deposition rate and negatively correlated with alveolar deposition rate. Among them, 0–10 μm particles were deposited throughout the bronchus and a large number of particles were deep into the alveoli, with the alveolar deposition rate as high as 56.3 %, while the alveolar deposition rate for particles of 10–20 μm decreased to 20.4 %, and for particles larger than 30 μm, the effect on the alveoli was smaller. [ABSTRACT FROM AUTHOR]

• A multicomponent acid solution consisting of SDBS,BS-12, HF and C6H8O7 was used to acidifie coal samples. • Acidification treatment can promote the formation of oxygen-containing functional groups C O and C O. • Provide an effective method for realizing high-efficiency clean mining of coal. • The micro mechanism of wettability was explained using molecular dynamics software. In order to explore the influence mechanism of different surfactants on the wettability of coal samples acidified with multi-component acid solutions, the effects of multi-component acid solutions and surfactant composite acid solutions on the functional groups and microcrystalline structures of coal samples were studied. In this paper, a multicomponent acid solution consisting of sodium dodecyl benzene sulfonate (SDBS), dodecyl dimethyl betaine (BS-12), hydrofluoric acid (HF), and citric acid (C 6 H 8 O 7) was used to acidification and contact angle experiments on coal samples. Fourier transform infrared spectroscopy (FTIR) results show that acidification can promote the formation of C O and C O, and the synergistic effect of surfactant BS-12 on multi-component acid solution is more prominent. X-ray diffraction (XRD) results show that the variation trend of aromatic lamellar diameter L a of coal samples is consistent with the aromatic layer spacing d 002. Surfactants can slow down the damage of multi-component acid solution to the microcrystalline structure of coal samples. The change of contact angle shows that the instantaneous synergistic wetting effect of BS-12 is better than that of SDBS. At the same time, molecular dynamics simulation technology was used to verify the effect of surfactants on the wettability of multi-component acid solutions. Therefore, this study provides a feasible method and theoretical guidance for improving the efficiency of coal production and utilization through chemical means. [ABSTRACT FROM AUTHOR]

Abstract The multi-satellite-retrieved (ESA CCI SM) and the Global Land Data Assimilation System-Noah-simulated (GLDAS-Noah) surface soil moisture (SM) datasets are compared for global drought analysis over a multi-decadal time period (1991–2015). Global drought events and their duration, frequency and severity are assessed on a grid basis with soil moisture anomaly percentage index (SMAPI). The results show that the ESA CCI SM and the GLDAS-Noah based SMAPI values are significantly (p < 0.05) correlated over most (83%) of the study region, of seasonally dependent. Both datasets show similar global patterns in drought duration, drought frequency and drought severity. The droughts present generally longer duration, higher frequency and more severity in arid and semi-arid regions than humid and sub-humid regions. The ESA CCI SM droughts are relatively higher in frequency and more intense in severity than the GLDAS-Noah SM droughts in many regions of the globe, while the two datasets show considerable differences in drought duration over arid, semi-arid and highly vegetated regions. For long-term trend detection, both datasets show high consistency in spatial pattern of SMAPI, with major significant drying trends in arid and semi-arid regions. Part (~20%) trends are confirmed by the Global Precipitation Climatology Centre (GPCC) precipitation dataset using the Standard Precipitation Index (SPI). The two SM datasets exhibit large disparity in trending drought duration, drought frequency and drought severity. Despite that, both show major significant increasing trends in arid and semi-arid regions. Both soil moisture datasets are capable of identifying extreme drought events reported in southern China, North America, Europe and southern Africa. The ESA CCI SM dataset is more effective in determining the severity and spatial pattern of drought excluding densely vegetated regions, while the GLDAS-Noah dataset is more powerful in detecting drought occurrence, even over densely vegetated regions. Overall, the ESA CCI SM and GLDAS-Noah SM show potential in global drought analysis, yet cautions should be paid to arid and semi-arid regions where drying trends are prevalent and large discrepancy presents between two datasets. Highlights • ESA CCI and GLDAS-Noah are significantly correlated in soil moisture drought index. • They show similar global pattern for drought duration, frequency and severity. • Two datasets exhibit similar spatial pattern and high consistency in drought trend. • Significant drying trends appear mainly in arid and semi-arid region. • ESA CCI is superior in drought detection except densely vegetated areas. [ABSTRACT FROM AUTHOR]

[Display omitted] • LVB experienced extensive conversion of forest and grass to agricultural land. • SWAT model presents good applicability in seasonal runoff modeling in LVB. • annual runoff generally increased with seasonal differences due to LULC changes. • hydrological drought aggravated over central western and eastern LVB with increased frequency and lengthened duration. Understanding the hydrological impacts of land use and land cover (LULC) changes is significant for sustainable water resources management and planning. The Lake Victoria basin (LVB) has experienced extensive forest and grass degradation and agricultural land expansion under rapid socio-economic development and population growth in recent decades. However, the hydrological impacts of LULC changes for the whole LVB is still poorly documented. This study first investigated the LULC changing effects of LVB, focusing on its impacts on the annual and seasonal runoff and the hydrological drought based on a distributed hydrological modeling of the Soil and Water Assessment Tool (SWAT). SWAT model showed comparatively good applicability in seasonal runoff simulation of LVB, with the percent bias (PBIAS) kept within ± 20 % and the coefficient of determination (R2) over 0.6 at ten hydrological stations available over the calibration and validation phases. Generally, the annual runoff obtained a monthly increase of 1.5 mm under collective LULC changes. Moreover, the LULC effects presented considerable seasonal dependence. A largest runoff increase of approximately 4 mm was detected in short rainy season attributed to the combined surface runoff and groundwater increase. Insignificant runoff increase was observed in long rainy and dry seasons under the complementary effects of surface runoff increase and groundwater decrease. Additionally, the hydrological drought was generally aggravated with increased drought frequency and lengthened duration, particularly for the central western and eastern regions with massive conversion of forest to agricultural land. The findings provide importance implication for rational water resources management and drought disaster response for the LVB. [ABSTRACT FROM AUTHOR]

Since compressed sensing was introduced in 2006, ℓ 1 − ℓ 2 minimization admits a large number of applications in signal processing, statistical inference, magnetic resonance imaging (MRI), computed tomography (CT), etc. In this paper, we present a neural network for ℓ 1 − ℓ 2 minimization based on scaled gradient projection. We prove that it is stable in the sense of Lyapunov and converges to an optimal solution of the ℓ 1 − ℓ 2 minimization. We show that the proposed neural network is feasible and efficient for compressed sensing via simulation examples. [ABSTRACT FROM AUTHOR]

Gradient refractive index (GRIN) micro-optics present unique opportunities for control of the chromatic properties, new degrees of freedom for optical design as well as the potential for use in new optical system applications. GRIN microgratings were imprinted in GeS 2 -Ga 2 S 3 -MCl (M = Na, K, Cs) chalcohalide glasses by microthermal poling, and the effects of the type and concentration of alkali cations on their performance were investigated. Two effective imprinting formation regions of the GRIN microstructure based on the poling saturation voltage (U s) and glass composition are observed at fixed poling time and temperature. The U s increases from 140 to 750 and 2600 V in accordance with the activation energy (E a) of alkali ions (Na+ to K+ and Cs+) increasing from 45.15 to 58.62 and 92.58 kJ/mol for studied samples. The saturated numbers of diffraction order (N s) of the gratings in these samples are 7, 9 and 6, respectively, the highest number being provided by the K+-containing sample. This is in accordance with imprinting-induced phase differences (0.14λ, 0.19λ and 0.09λ) measured in the fabricated samples containing Na+, K+ and Cs+ ions. Furthermore, the U s of samples decreases from 1500 to 300 V with four concentrations of K+ from 10 to 30%, associated with their E a of K+ decreasing from 69.62 to 53.46 kJ/mol, while N s increases from 8 to 14, which is attributed to the increase of the phase difference in the GRIN structures. The controllable GRIN microstructures are realized by adjusting the type and concentration of alkali cations in chalcohalide glasses, which is expected to drive the design of broadband GRIN microgratings. [ABSTRACT FROM AUTHOR]

• Identify soil moisture (SM) droughts in a 3-D domain. • Severe droughts mainly distributed in northeast and southwest of Southeastern Asia. • SM droughts were more serious in cold (aggravated) than warm season (alleviated). • The drought clusters shared two predominant routes of westward and southwest. • SM droughts propagated synergistically with precipitation and PET. Droughts evolve in space and time simultaneously, but its spatio-temporal propagation remains less explored. As one of the hotspot regions in global soil moisture (SM) drought, the Southeastern Asia supports billions of population and trillions of dollars in gross domestic product. Its high drought risk initiated a deep understanding of drought propagation in multiple dimensions for effective prevention. This study investigated the SM droughts with a merged dataset of remote sensing and land surface modeling over 1979–2016. Our results showed that 369 drought clusters and 145 drought events occurred. Spatially, severe droughts appeared mainly in southwest and northeast of the study region. Temporally, the droughts were more severe in cold season (winter and spring) than warm season (summer and autumn). In last four decades, the SM droughts alleviated in warm season but aggravated in cold season significantly, posing a challenge for drought mitigation, especially for spring crop growth vigorously. Furthermore, the drought clusters shared two predominant routes of westward and southwest. The westward route is for the droughts started in winter in south region, while the southwest route is for the droughts started in summer across the Yangtze River basin from northeast to southwest. At a drought event level, the SM drought propagated synergistically with precipitation and potential evapotranspiration (PET). Precipitation was generally the primary driver and PET the secondary, particularly for SM droughts lasting in summer and winter in south region. The intensity of PET usually enhanced in spring and summer with temperature increasing and crop growing. The findings in drought propagation provide essential spatiotemporal structure for mechanism exploration and important clues for drought prediction. [ABSTRACT FROM AUTHOR]

A series of MoVTeNbO x -mixed metal oxides were synthesized by high-pressure hydrothermal method. The effects of temperature and time during the preparation process on the structure and catalytic performance of MoVTeNbO x were investigated. It was demonstrated that high content of M1 phase (94.5%) MoVTeNbO x with typical needle-shape morphology and high surface abundance of V5+ (68.9%) could be fabricated by high-pressure hydrothermal method in a short time (30–60 min) without hydrogen peroxide post-treatment. The catalytic results of propane selective oxidation showed that the MoVTeNbO x sample synthesized at 200 °C for 30 min possessed the highest surface V5+ abundance and largest proportion of terminating (001) plane, displaying the highest selectivity (74.1%) for acrylic acid. Moreover, the prepared MoVTeNbO x showed excellent stability in high temperature continuous reaction. [Display omitted] • MoVTeNbO x was fabricated facilely by high-pressure hydrothermal technology. • This developed method could shorten preparation time dramatically. • High content M1 phase MoVTeNbO x could be obtained without H 2 O 2 post-treatment. • Synthesized MoVTeNbO x had high surface V5+ abundance of 68.9%. • As prepared MoVTeNbO x exhibited excellent catalytic performance. [ABSTRACT FROM AUTHOR]

• Expression of 1Dy12 in wheat mutant AS273 was decreased during grain development. • A stop codon caused by base change led to truncated translation of 1Dy12 in AS273. • The absence of 1Dy12 influenced the accumulation of seed storage proteins and GMPs. • The absence of 1Dy12 led to a larger size PBs and an inferior flour-processing quality. Dissecting the functions of high molecular weight glutenin subunits (HMW-GSs) is helpful for improving wheat quality via breeding. In this study, we used a wheat mutant AS273 in which HMW-GS 1Dy12 was silenced to investigate the silencing mechanism of 1Dy12 and its effects on gluten accumulation and flour-processing quality. Results suggested that the expression of 1Dy12 in AS273 was decreased by one fifth during grain development; a stop codon produced by a base mutation (C/T) led to truncated translation; the absence of 1Dy12 stimulated the accumulation of low molecular weight glutenin subunits (LMW-GSs), gliadins, and glutenin macropolymers, and was resulted in larger protein bodies; AS273 had an inferior flour-processing performance. Based on the outputs achieved in this study it is concluded that 1Dy12 makes important contributions to bread, sponge cake and biscuit-processing quality. [ABSTRACT FROM AUTHOR]

• The climatological spatial scales (CSS s) of meteorological droughts are investigated. • The CSS s of multi-timescale droughts in China are determined and attributed. • The CSS s generally show a significant decrease with increasing timescale. • The five climate anomalies have significant impacts on the multi-scale CSS s. • The climate anomalies and the CSS s show complex spatiotemporal interaction effects. This study investigates the climatological spatial scales (CSS s) of meteorological droughts in China and the linkages to climate variability. The Global Precipitation Climatology Centre monthly gridded precipitation with a spatial resolution of 25 km × 25 km for 1961–2010 is used. The standardized precipitation index at different timescales (1-, 3-, 6-, 9-, 12-, 24-, 36-, and 48-month) is applied to characterize meteorological droughts. The CSS s of meteorological droughts are calculated using a method considering spatial correlation and anisotropy. The relationships between the CSS s and main monsoons and climate teleconnections in five selected regions are quantified using dynamic spatial panel models. The five regions are South China (SC), the Yangtze River Valley (YRV), North China (NC), Northeast China (NE), and the Tibetan Plateau (TIB). The following results are obtained: (1) The CSS s of multi-timescale meteorological droughts in China are determined. The means of the CSS s at various timescales in China are 68.9, 73.8, 71.8, 69.7, 68.8, 65.9, 62.9, and 60.8 × 104 km2, respectively. The CSS s in eastern China generally show a significant decrease with increasing timescale. (2) Significant quantification relationships (R2 greater than 0.85) suggest that there is not a simple linear relationship between climate anomalies and the CSS s, but rather a complex spatiotemporal interaction including exogenous and endogenous interaction effects. The CSS s not only strongly depend on their neighbors on the same timescale but also significantly depend on the CSS s of neighbors on adjacent timescales. Three monsoon indices (Indian monsoon, East Asian monsoon, and western North Pacific monsoon) have significant impacts on the multi-timescale CSS variations in the five regions, especially for NE, YRV, SC, and TIB, while the El Niño–Southern Oscillation and Pacific Decadal Oscillation affect mainly SC and YRV. These findings could broaden our understanding of the spatiotemporal relationships of droughts and be useful for drought risk management. [ABSTRACT FROM AUTHOR]

• SMAP soil moisture (SM) biases are investigated based on core validation sites data. • The p.m. retrievals outperform a.m. retrievals due to better accuracy in clear days. • Dual channel algorithm has the potential to improve SM retrieval in bad weathers. • SM bias correlates negatively with soil temperature and positively with its bias. • Soil wetness, temperature and vegetation parameters jointly contribute to SM biases. The Soil Moisture Active Passive (SMAP) mission provides state-of-the-art global soil moisture (SM) datasets. However, seasonal SM biases and their contributing factors have not be systematically reviewed. This study evaluated the biases of SMAP V6 dual channel algorithm (DCA), single channel algorithm H-pol (SCA-H) and V-pol (SCA-V) SM products based on core validation sites data. All algorithms perform better under clear- than cloudy-sky, and in cloudless daytime than nighttime. Consecutive clear-sky benefits SM retrieval, progressively lowering the uncertainty of SM retrievals while at the cost of dry biases. Cloudy-sky deteriorates the quality of SM retrievals, and wet biases increase with the duration time of cloudy-sky. The modified V7 DCA has a major improvement, owning the potential to provide accurate retrievals under cloudy-sky. SMAP SM biases are co-determined by vegetation index, soil temperature and their biases, and a single factor only explains at most 54% variance in SM biases. Generally, SMAP SM bias is negatively correlated with soil temperature and positively correlated with its bias. SM bias correlates positively with vegetation index and its bias for single channel algorithms, and the underestimation of SM increases with vegetation density for DCA. To get a complete picture of SMAP SM biases, a total differential of radiative transfer equation is recommended for decomposing SMAP SM biases. To this end, more validation sites are required covering diverse land cover types and providing continuous data records. [ABSTRACT FROM AUTHOR]

[Display omitted] • The decadal runoff changes in two contrasting watersheds in the Tienshan Mountains were analyzed. • Water balance closure was achieved by considering remotely sensed snow/ice melt and actual evapotranspiration (ET). • Rainfall and snow/ice melt dominated the increasing of decadal runoff in the humid Kashi watershed. • Rainfall and human activity jointly dominated the increasing of decadal runoff in the arid Boertala watershed. • Most of the changes in snow/ice melt and ET were contributed from the high and low elevation regions, respectively. Water processes in the Tienshan Mountains have undergone great changes under the impacts of climate warming and human activities. Here, based on the Budyko framework, we investigated the respective contributions of climate change and human activities to decadal runoff changes (1982–2014) in two contrary watersheds, i.e., the humid Kashi watershed in the Yili River valley and the arid Boertala watershed in the Ebinur Lake basin, in the Tienshan Mountains, where closing the water balance is difficult due to the scarcity of precipitation gauges. To achieve closure of the decadal water balance of the study watersheds, we estimated evapotranspiration from a complementary relationship model and snow/ice melt using the degree-day method with the remote sensing snow cover product. We found that the increase of rainfall (+61.6 mm) and snow/ice melt (+57.3 mm) dominated the increase of runoff (+87.2 mm, from 398.2 mm in 1982–1992 to 485.4 mm in 1993–2014) in the Kashi watershed, contributing 47.1 mm (54.8%) and 43.8 mm (51.0%), respectively, to the increase of runoff. Unlike the Kashi watershed, human activities contributed −13.8 mm (−103.7%) to the runoff (+13.9 mm, from 61.4 mm in 1982–1997 to 75.3 mm in 1998–2014) in the Boertala watershed. Most of the increase in rainfall (+62.5 mm) and snow/ice melt (+13.6 mm) was consumed by the increase of ET (+64.0 mm) instead of runoff. Further analysis showed that most of the increases in snow/ice melt and ET were contributed from the high (>2500 m) and low (<1500 m) elevation regions, respectively. Snowmelt showed a decreasing trend in low elevation regions. Our study highlighted the importance of snow/ice melt and ET in understanding decadal changes in runoff in the Tienshan Mountains. [ABSTRACT FROM AUTHOR]

• A method to measure the spatial extent of drought at any location was proposed. • The parameters of the method were reasonably specified using sensitivity tests. • The method was tested over a humid region located in southern China. • The difference in spatial lengths of 8 directions showed the anisotropy of drought. • The spatial extents of multi-scale droughts decreased as the time scales increased. The spatial characteristics of droughts are important for understanding drought development and water resource allocation. Most previous studies mainly focus on the spatial display of drought characteristics and the identification of drought spatial extents. Little attention is given to measuring the spatial extent of drought at any location. To this end, a new framework was proposed for measuring the spatial areal extent of drought based on spatial autocorrelation and anisotropy principle. The Global Precipitation Climatology Centre monthly gridded precipitation data with a spatial resolution of 25 km × 25 km were used. The standardized precipitation index on a three-month scale (SPI-3) was applied to characterize meteorological droughts. The base period of 1961–2010 (50 years) was selected for calculating climatology lengths (Cls)/spatial extents (SPEs) of meteorological droughts over the Poyang Lake basin. The parameters of the proposed method, including the drought threshold (SPI ≤ −1), the number of search directions (8), search radius (500 km), distance step (25 km), bandwidth (56.95 km), and angle tolerance (22.5°), were examined using sensitivity tests. The results showed that notable differences in Cls of 8 search directions confirmed the spatial anisotropy of droughts. The statistics of SPEs of the SPI-3 series over the basin were reported. SPEs were mainly between 50 and 100 × 104 km2. The distinctive spatial pattern of the SPEs was revealed and characterized by a high-value belt from the northeast and southwest and two low-value areas. The SPI on other time scales (SPI-1/SPI-6/SPI-12) revealed similar characteristics as SPI-3. Moreover, SPEs are potentially associated with time scales, revealing a decreasing change (or increasing spatial fragmentation) as time scales increased. The proposed method based on anisotropy is reasonable and useful for mining the spatial characteristics of droughts and can be applied in other fields. [ABSTRACT FROM AUTHOR]