Quantifying the agreement and accuracy characteristics of four satellite-based LULC products for cropland classification in China

Various land use and land cover(LULC)products have been produced over the past decade with the development of remote sensing technology.Despite the differences in LULC classification schemes,there is a lack of research on assessing the accuracy of their application to croplands in a unified framework.Thus,this study evaluated the spatial and area accuracies of cropland classification for four commonly used global LULC products(i.e.,MCD12Q1V6,GlobCover2009,FROM-GLC and GlobeLand30)based on the harmonised FAO criterion,and quantified the relationships between four factors(i.e.,slope,elevation,field size and crop system)and cropland classification agreement.The validation results indicated that MCD12Q1 and GlobeLand30 performed well in cropland classification regarding spatial consistency,with overall accuracies of 94.90 and 93.52%,respectively.The FROMGLC showed the worst performance,with an overall accuracy of 83.17%.Overlaying the cropland generated by the four global LULC products,we found the proportions of complete agreement and disagreement were 15.51 and 44.72% for the cropland classification,respectively.High consistency was mainly observed in the Northeast China Plain,the Huang-Huai-Hai Plain and the northern part of the Middle-lower Yangtze Plain,China.In contrast,low consistency was detected primarily on the eastern edge of the northern and semiarid region,the Yunnan-Guizhou Plateau and southern China.Field size was the most important factor for mapping cropland.For area accuracy,compared with China Statistical Yearbook data at the provincial scale,the accuracies of different products in descending order were:GlobeLand30,FROM-GLC,MCD12Q1,and GlobCover2009.The cropland classification schemes mainly caused large area deviations among the four products,and they also resulted in the different ranks of spatial accuracy and area accuracy among the four products.Our results can provide valuable suggestions for selecting cropland products at the national or provincial scale and help cropland mapping and reconstruction,which is essential for food security and crop management,so they can also contribute to achieving the Sustainable Development Goals issued by the United Nations.

Improving model performance in mapping cropland soil organic matter using time-series remote sensing data

Faced with increasing global soil degradation,spatially explicit data on cropland soil organic matter(SOM)provides crucial data for soil carbon pool accounting,cropland quality assessment and the formulation of effective management policies.As a spatial information prediction technique,digital soil mapping(DSM)has been widely used to spatially map soil information at different scales.However,the accuracy of digital SOM maps for cropland is typically lower than for other land cover types due to the inherent difficulty in precisely quantifying human disturbance.To overcome this limitation,this study systematically assessed a framework of“information extractionfeature selection-model averaging”for improving model performance in mapping cropland SOM using 462 cropland soil samples collected in Guangzhou,China in 2021.The results showed that using the framework of dynamic information extraction,feature selection and model averaging could efficiently improve the accuracy of the final predictions(R^(2):0.48 to 0.53)without having obviously negative impacts on uncertainty.Quantifying the dynamic information of the environment was an efficient way to generate covariates that are linearly and nonlinearly related to SOM,which improved the R^(2)of random forest from 0.44 to 0.48 and the R^(2)of extreme gradient boosting from 0.37to 0.43.Forward recursive feature selection(FRFS)is recommended when there are relatively few environmental covariates(<200),whereas Boruta is recommended when there are many environmental covariates(>500).The Granger-Ramanathan model averaging approach could improve the prediction accuracy and average uncertainty.When the structures of initial prediction models are similar,increasing in the number of averaging models did not have significantly positive effects on the final predictions.Given the advantages of these selected strategies over information extraction,feature selection and model averaging have a great potential for high-accuracy soil mapping at any scales,so this approach can provide more reliable references for soil conservation policy-making.

Practices and Empirical Insights from the National Research Program for Key Issues in Air Pollution in Beijing-Tianjin-Hebei and Surrounding Areas

1.Introduction The United States began implementing policies against air pollution in earnest starting in the early 1970s,taking several decades and an economic recession to achieve reductions in air pollution.In contrast,China has reduced its air pollution by the same amount in only seven years[1].Compared with foreign countries.

聚对苯二甲酸乙二醇酯/石墨烯的氧气阻隔性能

通过熔融共混和微型注塑成型的方法制备了不同石墨烯(RGO)含量的聚对苯二甲酸乙二醇酯(PET)纳米复合材料。研究了不同注塑压力条件下,PET/RGO纳米复合材料的气体阻隔性能。结果表明,与纯PET相比,添加质量分数0. 5%的RGO,复合材料的氧气渗透率降低了85%。在微型注塑加工过程中,随着注塑压力增加,RGO在基体中取向,能够延长氧气的渗透路径,进而在较低RGO添加量的情况下能有效提高PET/RGO氧气阻隔性能。

Experimental study of osthole on treatment of hyperlipidemic and alcoholic fatty liver in animals

AIM： To evaluate the effects of osthole on fatty liver, and investigate the possible mechanism. METHODS： A quail model with hyperlipidemic fatty liver and rat model with alcoholic fatty liver were set up by feeding high fat diet and alcohol, respectively. These experimental animals were then treated with osthole 5-20 mg/kg for 6 wk, respectively. Whereafter, the lipid in serum and hepatic tissue, and coefficient of hepatic weight were measured. RESULTS： After treatment with osthole the levels of serum total cholesterol （TC）, triglyceride （TG）, lower density lipoprotein-cholesterol （LDL-C）, coefficient of hepatic weight, and the hepatic tissue contents of TC and TG were significantly decreased. The activity of superoxide dismutase （SOD） in liver was improved. In alcohol-induced fatty liver rats, the level of malondialdehyde （MDA） in liver was decreased. In high fat-induced fatty liver quails, glutathione peroxidase （GSH-PX） in liver was significantly improved. The histological evaluation of liver specimens demonstrated that the osthole dramatically decreased lipid accumulation. CONCLUSION： These results suggested that osthole had therapeutic effects on both alcohol and high fatinduced fatty liver. The mechanism might be associated with its antioxidation.

Effect of yellow rice wine on anti-aging ability in aged mice induced by D-galactose

The present study is focused on investigation of the health protective effect of yellow rice wine(YRW)in mice and the potential underlying mechanism.Symptoms of aging were induced in mice by using Dgalactose(D-gal),and different doses of YRW(4,8,and 12 mL/kg BW)were orally administrated to D-galtreated mice for a period of six weeks.The in vivo data obtained in the present study preliminary indicated that YRW markedly increased the activity of antioxidant enzymes and reduced the concentration of MDA both in the brain and liver.Furthermore,a forced swim test showed that moderate intake of YRW(8 mL/kg BW)significantly decreased the duration of immobility,reduced the blood content of urea nitrogen and lactic acid,and increased hepatic glycogen storage.Besides,results from the Morris water maze test suggested that YRW significantly reversed cognitive impairment and also alleviated neuroapoptosis in the experimental mice by regulating the gene expressions of Bax/Bcl-2 and caspase-3.The above results indicated YRW has a potential anti-aging effect in mice and provided us certain molecular evidence for this action.

Effect of pre-annealing treatment on the microstructure and mechanical properties of extruded Al–Zn–Mg–Cu alloy bars

Taking extruded Al–Zn–Mg–Cu alloy(7A04 alloy) bars as the research object, the effect and mechanism of pre-annealing treatments on the microstructure and mechanical properties of the aged alloy bars were investigated. The results show that a pre-annealing treatment at 350°C for 15 h before a T6 treatment substantially reduced the sensitivity of the microstructure and mechanical properties of the extruded 7A04 aluminum alloy specimens toward the extrusion temperature. The average grain sizes of the specimens extruded at 390 and 430°C after T6 treatment were 3.4 and 8.1 μm, respectively, and their elongations to failure were 7.0% and 9.2%, respectively. However, after pre-annealing + T6 treatment, the differences in both the grain sizes and the elongations of the specimens became small, i.e., their average grain sizes were 3.2 and 3.8 μm and their elongations were 12.0% and 13.3%, respectively. For the specimens extruded at the same temperature, pre-annealing treatment obviously improved the plasticity of the alloy, which is attributed to an increase in soft texture or to grain refinement in the specimens as a result of the pre-annealing + T6 treatment.

Pollutant emission reduction effect through effluent tax,concentration-based effluent standard,or both

There are numerous studies comparing different kinds of environmental taxes and standards.However,forms of environmental standards focused by former researchers are usually quantitybased limits/standards(e.g.pounds per day or pounds per unit of output).Concentration-based emission standard(e.g.milligrams per liter of wastewater) as one important form of environmental standard has not been given much attention.In this article,comparable estimates of their probable effect on enterprise pollution reduction will be developed for concentrationbased effluent standards,effluent taxes,and a combination of both.A linear simulation model is used to clearly and obviously compare the effects of effluent taxes and concentration-based standards within the same figure.With one detailed application to the paper industry,some enlightenment and conclusions-as well as the general applicability of these principles-are then provided:Under the same effluent tax rate,enterprises,groups,and industries that are cleaner will reduce more pollutants than those that have higher pollutant abatement costs.It is recommended that effluent taxes are set by avoiding cutting it even at one stroke and considering the feasibility of pollution-reducing technology in various industries.It is necessary to reduce MAC of enterprises to better stimulate enterprises' or industries' emission reduction by preferential measures,such as high tax rate coordinated by speeding up the depreciation of environmental protection equipment.

Identification of portal vein tumor thrombus with an independent clonal origin in hepatocellular carcinoma via multi-omics data analysis

Objective: Multiple mechanisms underlying the development of portal vein tumor thrombus(PVTT) in hepatocellular carcinoma(HCC) have been reported recently. However, the origins of PVTT remain unknown. Increasing multi-omics data on PVTTs in HCCs have made it possible to investigate whether PVTTs originate from the corresponding primary tumors(Ts).Methods: The clonal relationship between PVTTs and their corresponding primary Ts was investigated using datasets deposited in public databases. One DNA copy number variations dataset and three gene expression datasets were downloaded for the analyses.Clonality analysis was performed to investigate the clonal relationship between PVTTs and Ts from an individual patient.Differential gene expression analysis was applied to investigate the gene expression profiles of PVTTs and Ts.Results: One out of 19 PVTTs had no clonal relationship with its corresponding T, whereas the others did. The PVTTs with independent clonal origin showed different gene expression and enrichment in biological processes from the primary Ts. Based on the unique gene expression profiles, a gene signature including 24 genes was used to identify pairs of PVTTs and primary Ts without any clonal relationship. Validation in three datasets showed that these types of pairs of PVTTs and Ts can be identified by the 24-gene signature.Conclusions: Our findings show a direct evidence for PVTT origin and consolidate the heterogeneity of PVTTs observed in clinic.The results suggest that PVTT investigation at a molecular level is clinically necessary for diagnosis and treatment.

GLOBAL SIMPLE WAVE SOLUTIONS TO A KIND OF TWO DIMENSIONAL HYPERBOLIC SYSTEM OF CONSERVATION LAWS

This paper is concerned with the simple waves of a kind of two dimensional hyperbolic system of conservation laws,which can be obtained from the two dimensional relativistic membrane equation in Minkowski space.Using wave decomposition method,we get that a flow adjacent to a nonconstant state can be a global simple wave.Furthermore,the flow is covered by three families of characteristics,in which the first family of characteristics is straight and the others are curved,which is different to the almost related results.

Identifying hot spots of long-duration extreme climate events in the northwest arid region of China and implications for glaciers and runoff

China’s Northwest Arid Region(NAR),with dry and cold climate conditions and glaciers widely developed in the high mountains,provides vital water resources for Asia.The consecutive cold,warm,dry and wet days have much higher impacts on the water cycle process in this region than extreme temperature and precipitation events with short durations but high intensities.Parametric and nonparametric trend analysis methods widely used in climatology and hydrology are employed to identify the temporal and spatial features of the changes in the consecutive cold,warm,dry and wet days in the NAR based on China’s 0.5°×0.5°meteorological grid datasets of daily temperature and precipitation from 1961 to 2018.This study found that(1)the consecutive cold days(Cold Spell Duration Indicator,CSDI),and the consecutive dry days(CDD)decreased,while the consecutive warm days(Warm Spell Duration Indicator,WSDI),and the consecutive wet days(CWD)increased from 1961 to 2018,(2)and the eastern Kunlun Mountains were the hot spots where all of these consecutive climate indices changed significantly,(3)and the changes in these consecutive climate indices were highly correlated with the rise in the Global Mean Land/Ocean Temperature Index.The results indicated that winters tended to warmer and dryer and summer became hotter and wetter during 1961–2018 in the NAR under the global warming,which can lead to the sustained glacier retreat and the increase in summer runoff in this region,and the eastern Kunlun Mountains are the area where could face high risks of water scarcity and floods if the changes in these climate indices continue in the future.Given the vulnerability of the socio-economic systems in the NAR to a water shortage and floods,it is most crucial to improve the strategies of water resources management,disaster prevention and risk management for this region under climate change.

Heat and Humidity Transport Analysis Inside a Special Underground Building

The calculation of heat and humidity load serves as the cornerstone of Heating,Ventilation,and Air Conditioning(HVAC)design.Nevertheless,as the heat and humidity load characteristics of underground structures differ substantially from those of above-ground structures,it is a challenge to derive their accurate calculation procedure through engineering experience.Therefore,it is particularly important to carry out quantitative research on heat and humidity load.This study used Design Builder software to study the influence of the design state point of air conditioning in underground buildings on energy consumption.The study showed that compared with the single design temperature of 18℃,setting the temperature of 16℃ in winter and 22℃ in summer could reduce energy consumption by about 59%.And the hourly heat load,cooling load and humidity load in one year are simulated and calculated so as to quantitatively analyze the characteristics of the load.This provides a database for selecting suitable HVAC equipment.It is further emphasized that dehumidification is the key to HVAC design of underground structures,which provides a reference for similar engineering designs.

Nanowire-based transparent conductors for flexible electronics and optoelectronics

As the necessary components for various modern electronic and optoelectronic devices, novel transparent electrodes(TEs) with the low cost, abundance features, and comparable performance of indium tin oxide(ITO) are inquired materials. Metal nanowires(NWs) with the excellent photoelectric properties as next-generation TE candidates have widely applications in smart optoelectronic devices such as electronic skins, wearable electronics, robotic skins, flexible and stretchable displays. This review describes the synthetic strategies for the preparation of metal NWs, the assemble process for metal NW films,and the practical aspects of metal NW films with the desired properties in various low-cost, flexible,and solution-based photoelectric devices.

A new staging system for hepatocellular carcinoma associated with portal vein tumor thrombus

Background:A new staging system for patients with hepatocellular carcinoma(HCC)associated with portal vein tumor thrombus(PVTT)was developed by incorporating the good points of the BCLC classification of HCC,and by improving on the currently existing classifications of HCC associated with PVTT.Methods:Univariate and multivariate analysis with Waldχ2 test were used to determinate the clinical prognostic factors for overall survival(OS)in patients with HCC and PVTT in the training cohort.Then the conditional inference trees analysis was applied to establish a new staging system.Results:A training cohort of 2,179 patients from the Eastern Hepatobiliary Surgery Hospital and a validation cohort of 1,550 patients from four major liver centers in China were enrolled into establishing and validating a new staging system.The system was established by incorporating liver function,general health status,tumor resectability,extrahepatic metastasis and extent of PVTT.This staging system had a good discriminatory ability to separate patients into different stages and substages.The median OS for the two cohorts were 57.1(37.2-76.9),12.1(11.0-13.2),5.7(5.1-6.2),4.0(3.3-4.6)and 2.5(1.7-3.3)months for the stages 0 to IV,respectively(P<0.001)in the training cohort.The corresponding figures for the validation cohort were 6.4(4.9-7.9),2.8(1.3-4.4),10.8(9.3-12.4),and 1.5(1.3-1.7)months for the stages II to IV,respectively(P<0.001).The mean survival for stage 0 to 1 were 37.6(35.9-39.2)and 30.4(27.4-33.4),respectively(P<0.001).Conclusions:A new staging system was established which provided a good discriminatory ability to separate patients into different stages and substages after treatment.It can be used to supplement the other HCC staging systems.

A low-dimension structure strategy for flexible photodetectors based on perovskite nanosheets/ZnO nanowires with broadband photoresponse

Flexible photodetectors(PDs) have huge potential for application in next-generation optoelectronic devices due to their lightweight design, portability, and excellent large area compatibility. The main challenge in the construction of flexible PDs is to maintain the optoelectronic performance during repetitive bending, folding and stretching.Herein, flexible PDs based on ZnO nanowires(NWs) and CsPbBr3 nanosheets(NSs) were constructed by an integrated low-dimensional structure strategy. Benefiting from the flexibility of unique sheet and wire structures, the PDs were able to maintain excellent operational stability under various mechanical stresses. For example, the PDs exhibited no obvious changes in optoelectronic performance after bending for 1000 times. Additionally, the PDs exhibited an integrated broadband response ranging from ultraviolet to visible region due to the combination of the intrinsic light absorption capability of ZnO and CsPbBr3. The PDs demonstrated high responsivities of 3.10 and 0.97 A W^-1 and detectivities of 5.57×10^12 and1.71×10^12 Jones under ultraviolet and visible light irradiation,respectively. The proposed construction strategy for highly flexible and performance-integrated PDs shows great potential in future smart, wearable optoelectronic devices.

Intermolecular charge-transfer aggregates enable high-efficiency near-infrared emissions by nonadiabatic coupling suppression

Pursuing purely organic materials with high-efficiency near-infrared(NIR) emissions is fundamentally limited by the large nonradiative decay rates(k_(nr)) governed by the energy gap law. To date, reported endeavors to decelerate k_(nr) are mainly focused on reducing the electron-vibration coupling with the electronic nonadiabatic coupling assumed as a constant. Here, we demonstrated a feasible and innovative strategy by employing intermolecular charge-transfer(CT) aggregates(CTA) to realize high-efficiency NIR emissions via nonadiabatic coupling suppression. The formation of CTA engenders intermolecular CT in the excited states;thereby, not only reducing the electronic nonadiabatic coupling and contributing to small k_(nr) for high-efficiency NIR photoluminescence, but also stabilizing excited-state energies and achieving thermally activated delayed fluorescence for highefficiency NIR electroluminescence. This work provides new insights into aggregates and opens a new avenue for organic materials to overcome the energy gap law and achieve high-efficiency NIR emissions.

Enhancement of adjustable localized surface plasmon resonance in ZnO nanocrystals via a dual doping approach

Recently, the localized surface plasmon resonance （LSPR） concept was expanded from noble metals to doped semiconductor nanocrystals （NCs）. However, the strengthening of the intrinsically very weak LSPR in NCs remains a great challenge for its applications in optics, electronics and optoelectronics fields. In this work, we report on the remarkable strengthening and controllability of LSPR in ZnO through a dual-doping strategy. First, high quality In-doped ZnO （IZO） NCs with intense LSPR were synthesized by a simple single-pot method. Importantly, the LSPR can be tuned by simply adjusting the concentration of In dopant, as well as by UV light irradiation （photo-induced doping）. The pattern of electricity of an IZO NC film matches the shift of LSPR independent of dopant concentration. The UV light irradiation clearly enhanced the electrical properties of the films （350 fl/sq） due to increase carrier density explained by LSPR and confirmed by X-ray photoelectron spectroscopy, The IZO NCs can be easily dispersed in various organic solvents and serve as inks for assembling uniform films via solution processes. These IZO NC ink is promising for application in next-generation solution-based field effect transistors and other optoelec- tronic devices.