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Air pollution is one of the most important factors affecting the solar radiation reaching the earth’s surface under the clear (cloudless) sky conditions. In this work, six typical cities with serious pollution located in the north, northeast, eastern, central, southwest, and southern regions of China: Beijing, Shenyang, Shanghai, Wuhan, Wenjiang and Guangzhou were selected. The influence of air pollution on global and diffuse solar radiation (Rsand Rd) under clear sky condition was quantitatively analyzed, based on the historical daily meteorological data from January 2014 to December 2020. The results showed that the highest Rsattenuation ratio of the above six cities appeared in spring, autumn, winter, summer, autumn and winter, respectively. The largest Rdincrement ratio of the six cities appeared in summer, spring, autumn, summer, autumn and spring, respectively. From 2014 to 2020, the relative attenuation of Rscaused by air pollution (AQI > 100) was largest in Beijing (6.03%), followed by Shanghai (4.21%), Wenjiang (4.15%), Shenyang (3.28%) and Wuhan (3.14%), while Guangzhou (1.32%) had the smallest relative attenuation. Additionally, the Rdrelative increment was largest in Beijing (16.21%), followed by Shanghai (8.78%), Wenjiang (8.13%), Shenyang (7.76%) and Guangzhou (5.96%), while Wuhan (2.57%) had the smallest relative increment.

Ochratoxin A (OTA), primarily produced by the fungi belonging to the species of Aspergillus and Penicillium, is one of the most common mycotoxins found in cereals and fruits. In addition to resulting in huge economic losses, OTA contamination also poses considerable threat to human and livestock health. Microbial degradation of mycotoxins has been considered with great potential in mycotoxins decontamination. In a previous study, Bacillus velezensis E2 was isolated by our laboratory and showed appreciable inhibitory effect on Aspergillus flavus growth and aflatoxin production in rice grains. In this study, B. velezensis E2 was investigated for its ability to remove OTA and biocontrol against the ochratoxigenic Aspergillus westerdijkiae fc-1. The results revealed that B. velezensis E2 has considerable inhibitory effect on A. westerdijkiae fc-1 both on PDA medium and pear fruits, with inhibitory rate of 51.7% and 73.9%, respectively. In addition, its ability to remove OTA was evaluated in liquid medium and the results showed that more than 96.1% of OTA with an initial concentration of 2.5 μg/mL could be removed by B. velezensis E2 in 48 h. Further experiments revealed that enzymatic transformation and alkaline hydrolysis might be the main mechanisms related to OTA degradation by B. velezensis E2, with ring open ochratoxin α (OP-OTα) as a possible degradation product. Our study indicated that the B. velezensis E2 strain could be a potential bacterial candidate in biodegradation of OTA and biocontrol against A. westerdijkiae fc-1.

Based on observation data from January 1st to December 31st in 2014 at Maduo Site, which is located near the Yellow River source area in the Qinghai-Tibet Plateau, this research examined how the surface flow of alpine meadow underlying surface varies. The applicability of the land-surface process models CLM5.0 and CLM4.5 in alpine grassland was also tested. The findings revealed that total radiation in the Yellow River source area was lower in the winter but quickly increased after mid-March, peaked in June or July, and then gradually decreased. The surface reflected radiation was affected by both the total radiation and surface albedo. Its seasonal variation showed different characteristics than the total radiation. Due to the snow on the surface, the short-wave radiation reflected by the surface was larger in winter, while the surface reflected radiation in summer was relatively small, especially after the rainy season. Long-wave surface radiation followed the same seasonal pattern as air counter radiation, with a low point in winter and a high point in summer. Due to cloud cover and other variables, however, long-wave surface radiation was larger than atmospheric counter radiation. The sensible heat flux and net radiation varied similarly until July (rainy season), but after July, the latent heat flux and net radiation followed the same pattern until the soil was frozen in early November. For the whole year, the study of regional surface flux was mainly focused on latent heat flux. Corresponding to sensible heat and latent heat, the daily average of soil heat flux was above 0 from mid-March to late August, which meant that the soil heat flux was transmitted from the surface soil to the deep layer, while the rest of the time showed a negative, with soil heat flux transmitted from the deep layer to the surface soil. In late March, the daily average heat flux of soil was abnormally large, which was related to the melting of frozen soil. Generally, for the whole year, soil heat flux was transmitted from the deep layer to the surface soil. The simulation results of CLM5.0 and CLM4.5 for radiation flux and surface heat flux are very close to the observed values, especially CLM5.0. This indicates that the simulation effect of the model in Alpine Grassland in the source region of the Yellow River has been significantly improved after improving many parameterization schemes and dynamic processes in CLM5.0. However, the soil freezing and thawing process and snow parameterization scheme in CLM need to be further improved. Generally, the daily average CO2 flux during the frozen period of soil was 0. In May, September, and October, the respiration of alpine meadows dominated, surface releasing CO2, while in early and middle June, photosynthesis played the leading role, surface absorbing CO2. During the period from late June to mid-August, when both the moisture and temperature of soil were higher, and the surface vegetation experienced rapid growth, the daily average CO2 flux increased sharply. On the contrary, when the frozen soil melted, the CO2 flux released by the surface increased significantly.

Photovoltaic (PV) power plants have shown rapid development in the renewable sector, but the research areas have mainly included land installations, and the study of fishery complementary photovoltaic (FPV) power plants has been comparatively less. Moreover, the mechanism of local microclimate changes caused by FPV panels has not been reported. This work revealed this mechanism using a physical model to illustrate the impact of FPV power plants in a lake on the environment. The results indicated that the lake becomes a heat sink after deploying the PV panel on water. The comprehensive albedo (0.082) decreased by 18.8% relative to the free water surface (0.101). The water energy change was dominated by the water–air vapor pressure deficit. In addition, the FPV panels had a heating effect on the ambient environment; however, the range of this effect was related to the water depth. The installation had an obvious heating effect on surface water.

The rapid development of photovoltaic plays an important role in achieving the carbon-neutral goal. How to improve the conversion efficiency and power generation of solar photovoltaic has always been a focus issue. However, more attention is paid to the impact of photovoltaic panel working temperature on the performance of photovoltaic power generation, and how air temperature affects photovoltaic power generation has been ignored. This paper compared and analyzed the impact of the difference in air temperature between lake and land on the revenue of photovoltaic power generation, and established the functional equation between photovoltaic power generation, air temperature and solar radiation, and revealed the relationship between air temperature, solar radiation and photovoltaic power generation.

In order to identify impacts of photovoltaic (PV) power plant on surface radiation, this paper conducted a comparative study on the surface radiation and surface albedo characteristics between the PV site and reference site in the Gobi area in Xingjiang, China in the summer of 2020. The results show that, the upward long-wave radiation at the PV site was significantly lower than that at the reference site in the night, while the two were basically the same during the daytime. The average surface albedo at the PV site (0.14) was 39.1% lower than that at the reference site (0.23). Net radiation was higher at the PV site than that at the reference site throughout the whole day. The average net radiation of the underlying surface at the PV site was 30.7% more than that at the reference site, 75% of which was contributed by lower upward shortwave radiation and 25% was due to nocturnal lower upward longwave radiation at the PV site.

Wildfires have great impact on the global ecosystem and human society, so the prediction and prevention of wildfires is necessary. This study used the MOD14A2 data, the NCEP/NCAR and ERA5 Reanalysis data, the GFEDv4 data and the Scripps O2 data to analyze the correlations between the area of wildfires and meteorological elements, and used the oxygen concentration to improve the McArthur Forest Fire Danger Index (FFDI). The following results were obtained: 1) During 2001 to 2015, the year of 2002 was the year with the most wildfires in the world, and August was the month with the most wildfires in a year. Northern Africa, Southern Africa and South America are the main wildfires-affected areas, accounting for nearly 80% of the global wildfires area in these 15 years. 2) Globally, the correlation coefficient between temperature and wildfires area is 0.47; for wind speed, it is 0.17; for precipitation, it is -0.41; for relative humidity, it is -0.19; and for oxygen concentration, it is more than 0.6. 3) The improved McArthur Forest Fire Danger Index (FFDInew) constructed by using the original FFDI and oxygen concentration can better reflect the fire risk in Australia. This study emphasized the important impact of changes in oxygen concentration on fires. It is of great significance for the management, prediction and prevention of wildfires.

The simulation performance of the land surface model Community Land Model 5.0 (CLM5.0) is tested by using the eddy correlation system and micrometeorological tower observational data at the Maqu observation field in 2016. The results show that the CLM5.0 model has a good simulation effect on the soil temperature and can well reflect the seasonal variation characteristics of soil temperature. In addition, the model can well simulate the seasonal variation in shallow soil moisture (5 cm and 10 cm). However, the deviations between the simulated and observed values are large. CLM5.0 cannot simulate the water holding capacity of shallow soil well, resulting in its underestimation. The simulation performance of the upward longwave radiation and net radiation is substantially better than that of the upward shortwave radiation due to the change in surface albedo caused by precipitation from March to July. CLM5.0 can also well reproduce the variation trend of the latent heat flux and 5 cm soil heat flux (heat exchange of soil at 5 cm). When the leaf area index (LAI) and Medlyn slope values are changed to 10%, 20%, and 50% of the default values, the simulation effects of soil moisture at depths of 5 cm and 10 cm are significantly improved, and the best simulation effects are achieved at 0.5 times the default values. This result indicates that lower LAI and Medlyn slope values are more suitable for simulating shallow soil moisture.

Rapid progress of solar photovoltaic (PV) technology has caused growing interest in understanding interactions between large scale PV plants and near-surface atmosphere. However few attempts have been made to quantify the impact of PV modules on surface radiative forcing and energy partitioning process. Here, this issue is explored experimentally and analytically in the two adjacent sites located at the PV plant and the natural barren field respectively in Wujiaqu in Xinjiang of China. The results showed that the physical effect of PV panels is not symmetrical in the whole day. During the daytime, compared with the reference site, net shortwave radiative forcing increases 8%, a warming effect on the integrated underlying surface (0.1 K) and a cooling effect (∼-2.6 K) on the ground surface were found in the PV plant. 9.2% of the net radiation (NR) was converted into electric energy (PE), sensible heat flux (H) increased by 30.6% hence resulted in the convection heating effects of 0.64 K and 0.32 K on the near-surface air temperature at the height of 2 m and 10 m respectively, while latent heat flux (LE) and ground surface heat flux (GS) decreased by 49% and 3% respectively related to the reference site. At night, PV panels produce a cooling effect of −0.2 K and −2.3 K on the ground and integrated underlying surface respectively, and less GS is released in the PV plant which contribute to the cooling effects of −0.24 K and −0.08 K on the air temperature at the height of 2 m and 10 m respectively related to the reference site. In the whole day, in the PV plant, H increased by 27.6%, LE and GS decreased by 47.4% and 6.7% respectively, air temperature increased by 0.16 K and 0.1 K at 2 m and 10 m respectively.

Summary The inferior light extraction efficiency (LEE), which is generally less than 20%, based on optical modeling, and the difficulty in achieving white emission are the two main challenges in the metal-halide-perovskite light-emitting diode (PeLED) field. Herein, we report a simple and efficient approach to construct high-performance white PeLEDs with much-enhanced LEE by coupling a blue PeLED with a layer of red perovskite nanocrystal (PeNC) down-converter through a rationally designed multilayer semitransparent electrode (LiF/Al/Ag/LiF). The red PeNC layer allows the extraction of the trapped waveguide mode and surface plasmon polariton mode in a blue PeLED and converts them to red emission, resulting in over 50% LEE improvement. Simultaneously, the complementary emission spectrum of blue photons and down-converting red photons contributes to a white PeLED with a high external quantum efficiency and luminance of more than 12% and approximately 2,000 cd m−2, respectively, which represent state-of-the-art results in this field.

Despite demonstrating higher photoluminescence quantum yield and better ambient and operational stability than organic–inorganic hybrid perovskites, all-inorganic perovskites encounter the problem of inferior film quality and interfacial electrical properties, which limits the resultant device performance. In this study, three polymers, P4a–c, bearing distinct pendant groups based on a similar conjugated group are synthesized and employed as an interlayer to modify the PEDOT:PSS/CsPbBr3 interface. Due to the pendant design, P4a–c possess deep-lying HOMO levels and high transparency across the visible range. The different structures of the pendant groups in P4a–c are shown to result in their different propensity in energy-level modulation and solid-state aggregation, which plays a non-trivial role in affecting the resulting device performance. Due to the more appropriate energy levels and better regulation of CsPbBr3 crystals, P4c with a polar bridge moiety is shown to better mediate the performance of the derived device. The P4c-mediated PeLED delivers six times enhanced luminance (Lmax, ∼36 000 cd m−2) and 3.6 times enhanced external quantum efficiency (EQE, 2.16%) as compared to the control device (∼6000 cd m−2, 0.60%). Notably, all the devices using P4a–c interlayers deliver a lower turn-on voltage than the control device, clearly revealing the positive role of P4a–c interlayers on diminishing the barrier across the associated interface to improve charge injection efficiency.

Colloidal lead-halide perovskite nanocrystals (LHP NCs) have emerged over the past decade as leading candidates for efficient next-generation optoelectronic devices, but their properties and performance critically depend on how they are purified. While antisolvents are widely used for purification, a detailed understanding of how the polarity of the antisolvent influences the surface chemistry and composition of the NCs is missing in the field. Here, we fill this knowledge gap by studying the surface chemistry of purified CsPbBr

Land-atmosphere interaction is one of the important causes of climate change. The accurate characterization of physical mechanism of the soil layer can help us better understand the land-atmosphere interaction. As one of the important thermal properties of soil, soil thermal diffusivity is an important parameter reflecting soil thermal conductivity and a necessary condition for simulating soil thermodynamic environment. Based on the comparison of several methods for calculating soil thermal diffusivity (amplitude method, phase method, logarithmic method, arctangent method, Laplace method and numerical methods), this paper develops a new soil thermal diffusivity model (Thermal conduction-convection method based on Fourier series boundary condition for calculating soil thermal diffusivity, TCCMF) and compares the results of the new model with other methods. The results show that: (1) The accuracy of the results obtained by the amplitude method, phase method, logarithmic method, and arctangent method is not high enough; the Laplace method can better solve the effects of extreme weather or non-periodic changes in soil temperature. (2) When the numerical methods are used to solve the thermal conduction equation, the Crank-Nichalson-Sch format is unconditionally stable, the data utilization rate is higher, the obtained soil thermal diffusivity is less discrete, and the result is more accurate. (3) The new model (TCCMF) uses the Fourier series method, which is easy to calculate, and has more complete physical process and more flexible precision control. The simulation results of soil temperature using this method show that this method (TCCMF) has better simulation accuracy, indicating that it has potential value in simulating soil thermodynamic characteristics and land-atmosphere interaction.

The air micro- and nanobubbles on a silicon wafer surface, generated by ethanol–water exchange method in THF solution, are found with anomalous small contact angles on the gas side due to the pinni...

The crystallization process of a droplet of tetrahydrofuran (THF) solution on a silicon wafer is studied based on the in situ observation with a high-resolution atomic force microscope. On the basi...

Shallow soil refers to the soil layer within the 50 cm depth. Shallow soil temperature (ST) directly or indirectly affects many processes in the soil, such as seed germination, plant growth, and water evaporation. Therefore, the study of shallow ST is of great significance in understanding the surface energy, water cycle, ecology and climate change. This work collected observational data from 141 meteorological stations on the Qinghai-Tibet Plateau from 1981 to 2020 and ERA5 reanalysis data, used the “Moving Surface Spline Interpolation Algorithm Based on Green’s Function” and “Fuzzy C-means algorithm”, and analyzed the temporal and spatial change characteristics of ST at different levels. The results showed that 1) the temperature increase of 0–20 cm (the surface layer of the shallow soil) was roughly the same. The average annual ST was 9.15–9.57°, and the interdecadal variabilities were 0.49–0.53 K/10a. The average annual ST of 40 cm (the bottom layer) was 8.69°, and the interdecadal variability reached 0.98 K/10a. 2) Considering the 7 regions, the warming trend was obvious, and there were certain regional differences. The average annual ST in different regions ranged from 5.2 (northeastern Plateau) to 17.1 °C (western Sichuan Plateau), with a difference of nearly 12 K. The standard deviation ranged from 0.40 (western Sichuan Plateau) to 0.61 K (Qiangtang Plateau), with a difference of 0.21 K. 3) The errors of the obtained grid data were basically less than 3%, which were much smaller than the errors obtained from the ERA5 reanalysis data. This work is significant for understanding the characteristics of ST evolution and land‒atmosphere interactions on the Qinghai-Tibet Plateau and provides important data support for improving the underlying surface boundary conditions of models.

Gas hydrate is a nonstoichiometric crystalline material. It is attracting more and more attention not only because natural gas hydrate is a potential energy resource, but also because hydrate-based technologies can be potentially applied to the industry of energy and environment such as energy storage, carbon sequestration, etc. The nucleation mechanism of gas hydrate is a key issue in studying reservoir formation of natural gas hydrate and the kinetic properties of gas hydrate as an energy-storage media. Molecular dynamics simulation can provide microscopic insights into molecular-scale understanding of hydrate nucleation. In this review, the advances on the study of heterogeneous hydrate nucleation by molecular dynamics simulation are summarized, with a specific focus on the factors affecting nucleation processes. The interfacial energy barrier for nucleation will be lowered by molecular structure of interfacial water between hydrate and solid substrate. The interface and surface properties of solid substrate, including hydrophilicity and hydrophobicity, surface roughness, layer-accumulated adsorption potential, crystallinity and surface layer-charge are also recognized as being associated with the process of hydrate nucleation by influencing the dynamics of gas and water molecules. In case of hydrate nucleation in confined pore space, confinement effect, pore size and elasticity are identified as the controlling factors.

Quasi-2D perovskites have long been considered to have favorable "energy funnel/cascade" structures and excellent optical properties compared with their 3D counterparts. However, most quasi-2D perovskite light-emitting diodes (PeLEDs) exhibit high external quantum efficiency (EQE) but unsatisfactory operating stability due to Auger recombination induced by high current density. Herein, a synergetic dual-additive strategy is adopted to prepare perovskite films with low defect density and high environmental stability by using 18-crown-6 and poly(ethylene glycol) methyl ether acrylate (MPEG-MAA) as the additives. The dual additives containing COC bonds can not only effectively reduce the perovskite defects but also destroy the self-aggregation of organic ligands, inducing the formation of perovskite nanocrystals with quasi-core/shell structure. After thermal annealing, the MPEG-MAA with its CC bond can be polymerized to obtain a comb-like polymer, further protecting the passivated perovskite nanocrystals against water and oxygen. Finally, state-of-the-art green PeLEDs with a normal EQE of 25.2% and a maximum EQE of 28.1% are achieved, and the operating lifetime (T50 ) of the device in air environment is over ten times increased, providing a novel and effective strategy to make high efficiency and long operating lifetime PeLEDs.

Polythiophenes (PTs) are promising donor materials for the industrialization of polymer solar cells (PSCs) due to the merits of easy synthesis, low cost, and large-scale producibility. The rapid progress of non-fullerene acceptors requires the development of new PTs for use in non-fullerene PSCs. In this work, we present a set of PTs with different degrees of backbone fluorination (P6T-F00, P6T-F50, P6T-F75, and P6T-F100) to investigate the effect of fluorination on the photovoltaic properties of PTs in non-fullerene PSCs. Upon increasing fluorine content, the PTs tend to have higher crystallinity, higher absorption coefficients, and enhanced relative dielectric constants. When blended with a non-fullerene acceptor EH-IDTBR, the blend films show increased photoluminescence quenching efficiency, reduced charge recombination loss, and extended charge carrier lifetime along with increasing fluorine content of PTs. These positive factors collectively result in dramatically improved power conversion efficiency...

In this work, a molecular dynamics simulation was conducted to study the microscopic mechanism of how nitrogen bubbles affect the formation of THF hydrates at the molecular level. The results obtained reveal that the nitrogen bubble can promote the formation of THF hydrates. In the system with a nitrogen bubble, more THF-filled cages were generated, and the crystal structure was more orderly. The promotion of nitrogen bubbles on hydrate crystallization comes from the dissolution of nitrogen molecules. Some of dissolved nitrogen molecules can be enclosed in small hydrate cages near the nitrogen bubble, which can serve as stable sites for hydrate crystal growth, resulting in the fact that THF-filled cages connected with N2-filled cages are much more stable and have a long lifetime. The results in this work can help to understand the promotion effect of micro- and nano-air bubbles on the crystallization of THF hydrates.

Molecular dynamics simulations were performed to study the effects of temperatures, pressures, and methane mole fractions on the generation behaviors, dynamic properties, and interfacial structures of methane gas bubbles. Methane gas bubbling can be promoted by high temperatures and high mole fractions of methane, which come from the generation of larger methane clusters in solution. Bubbles were found to be highly dynamic, with more methane molecules exchanging between bubbles and the surrounding solution at high pressures and in systems with high mole fractions of methane. The interfacial structures between bubbles and the surrounding solution were rough at a molecular level, and the roughness of the outermost methane and water molecules was high at high temperatures, low pressures, and in systems with high methane mole fractions. The dissolution of methane molecules depended on the interactions between the outermost methane and water molecules, which would become stronger with decreasing temperatures, increasing pressures, and decreasing methane mole fractions. The results obtained can help in understanding both the generation behaviors of bubbles when gas hydrates decompose and the re-nucleation behaviors of gas hydrates in the presence of bubbles.

Hypothesis Quartz is one of the most common but important minerals, and its wettability plays a significant role in affecting various natural and industrial processes. Studies have revealed that different crystal faces of quartz are with different wettabilities, but its mechanism is still vague. Experiments and simulations For specifying the mechanism of crystal face dependent wettability, the contact angles of three different liquids on the crystal faces of α-quartz are measured; the time-of-flight secondary ion mass spectrometry (ToF-SIMS) is employed to establish the crystal surface models; molecular dynamics (MD) simulations with the surface models are performed to understand the wetting behavior at molecular scale. Findings Based on the contact angle measurements, the wettabilities of different crystal faces of α-quartz are found different, which can be directly attributed to the concentration of hydroxyl group on crystal faces based on ToF-SIMS results. MD simulations yield consistent results with the contact angle order recognized from experiments, revealing that the surface hydroxyl group controls the wettability of α-quartz crystal faces. It is also recognized that the pristine surface atomic arrangement, especially the surface concentration of unsaturated bond (an intrinsic property of α-quartz), is the intrinsic cause of the difference in the concentration of hydroxyl group of the crystal surface.

This study selected the two adjacent eddy covariance observational towers at the FPV in Yangzhong, Jiangsu Province of China to explore the issue. The results indicated that the percent frequency of east wind lower 4 m·s-1 at 2 m decreased by 25.3% in FPV site compared with the REF site. The FPV array have a heating effect on the ambient. The average air temperature difference in two sites at 2 m and 10 m are 0.3 K and 0.1 K during the heating period. The net radiation increased by 47.8 W·m-2 in two sites. Sensible heat is increased by 7.9 W·m-2 due to the heating effect. Latent heat in the two sites are contrary to the sensible heat (-13.0 W·m-2). The difference of the water storage heat is 32.18 W·m-2, which implies the water absorbs higher heat in the FPV site than the REF site. This work illustrated the importance of observational experiments to animate process-based understanding combined with FPV systems. It further provides the scientific basis to establish the FPV energy balance models based on the observation that may be used to reveal the impact of utility-scale FPV deployment on climatic effects.

We used the data of observational site in photovoltaic power plant (PV site) and reference site in summer 2020 to compare the characteristics of surface energy flux of PV site and Gobi underlying surface. We defined the photovoltaic virtual flux and calculated the proportion of photovoltaic power generation in the net radiation by using daily power generation and generating hours. The results show that the net radiation of PV site was larger than that of reference site throughout the day. Compared with the reference site, the sensible heat flux and latent heat flux of PV site increased by 6% and 53.5%, respectively. Sensible heat flux, soil heat flux, latent heat flux and photovoltaic virtual flux accounted for 43.2%, 14.5%, 8.6% and 6.1% of the net radiation, respectively. The sensible heat accounted for the largest proportion, the energy balance closure increased from 0.6 to 0.67 in the daytime.

Here we provide a comprehensive review of a newly developed lighting technology based on metal halide perovskites (i.e. perovskite light-emitting diodes) encompassing the research endeavours into materials, photophysics and device engineering. At the outset we survey the basic perovskite structures and their various dimensions (namely three-, two- and zero-dimensional perovskites), and demonstrate how the compositional engineering of these structures affects the perovskite light-emitting properties. Next, we turn to the physics underpinning photo- and electroluminescence in these materials through their connection to the fundamental excited states, energy/charge transport processes and radiative and non-radiative decay mechanisms. In the remainder of the review, we focus on the engineering of perovskite light-emitting diodes, including the history of their development as well as an extensive analysis of contemporary strategies for boosting device performance. Key concepts include balancing the electron/hole injection, suppression of parasitic carrier losses, improvement of the photoluminescence quantum yield and enhancement of the light extraction. Overall, this review reflects the current paradigm for perovskite lighting, and is intended to serve as a foundation to materials and device scientists newly working in this field.

The effects of soil seasonal freezing and thawing process on land surface heat fluxes were analyzed with two years observation data from 2013 to 2014 . The results showed that the sensible heat, latent heat and soil heat flux have no change significantly during the soil freezing stage. The sensible heat flux increased significantly, the latent heat flux decreased significantly, and the corresponding wave ratio increased during the frozen period. The soil moisture and soil heat flux increases rapidly, sensible heat flux and surface long wave radiation decrease rapidly, latent heat flux increases rapidly during the thawing stage. The thawing process of frozen soil has an obvious effect on the heat flux of soil, which increases the heat flux from surface soil to deep soil because of that the heat absorption of ice in thawing process.

Surface albedo is one of the most important properties of underlying surface. However, errors still exist in the calculation of the surface albedo because of complex influencing factors. Understanding the relationship between the surface albedos in different wavebands, and soil moisture will provide theory basis for the parameterization of surface albedos. In this paper, using the data on the spectral radiation and soil moisture observation in Dunhuang, China, from August to October 2016, the spectral radiation characteristics of the underlying surface in this arid Gobi area, the variation characteristics of the surface spectral albedo and its relationship with 2-cm soil moisture were analyzed. The results show that the decrease of the angle of the sun due to seasonal change is the reason of the decrease of NIR, GR, VIS, and UV. The surface albedos in different wavebands are affected by the surface soil moisture, and they exhibit obvious anti-correlations. During the observation period, the average surface albedo of NIR, GR, VIS, and UV is 0.263, 0.230, 0.204, and 0.096, respectively, while the correlation coefficient with 2-cm soil moisture is − 0.522, − 0.678, − 0.804, and − 0.812, respectively. When solar altitude is larger than 40°, the correlation coefficients between the NIR, GR, VIS, and UV surface albedos and 2-cm soil moisture are becoming larger. And the linear regression coefficients between the NIR, GR, VIS, and UV surface albedos and 2-cm soil moisture are becoming smaller. Shorter wavelengths correspond to stronger relationships between the surface albedo and soil moisture. At longer wavelengths, the decrease in the surface albedo due to the increase in soil moisture is sharper.

The mechanisms governing variations in autumn precipitation are complicated and influenced by a number factors. This paper analyses the characteristics of autumn precipitation in China and investigates the influence of Asian polar vertex contraction on rainfall deficits in China and relevant mechanisms. Autumn precipitation decreased significantly from 1961 to 2012 in mid- and southern China, and the area of the Asia polar vortex (AAV) has decreased significantly since 1988. Asian polar vertex contraction is found to be an important factor in these autumn rainfall deficits in China through the following mechanism. Asian polar vertex contraction causes anomalously high geopotential heights in East Asia (from 25°N to 55°N) and low heights north of 65°N in the upper and lower troposphere, weakening meridional gradients in geopotential height. In the upper troposphere, the westerly and northerly winds are strengthened over high latitudes and westerly winds and the subtropical westerly jet are weakened over the East Asian mid-latitudes. In the lower troposphere, westerly winds are strengthened over high latitudes, westerly winds are weakened in East Asia and along the southern periphery of the Tibetan Plateau, and northerly winds in mid- and southern China are clearly strengthened. Hence, autumn rainfall decreases in mid- and southern China.