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[Objective] Regional carbon storage is closely related to land use. Under the goal of “carbon peaking and carbon neutrality”, researches about land use change calculations in significant regions play an important role on coordinating and optimizing regional land use patterns, improving the future carbon sequestration potential of regional ecosystems. [Methods] Taking Western Sichuan Plateau as the study area this paper predicts land use changes under different scenarios from 2020 to 2030, and estimates regional carbon storage changes by using revised land use carbon density data and land use data in 2000, 2010 and 2020. [Results] (1) From 2000 to 2020, grassland gradually decreased from 65.20% to 63.65%, forest continuously expanded from 31.73% to 32.92%, unused land firstly decreased and then increased and the net increase rate is 0.57%, water area and farmland firstly increased and then decreased and their net decrease rate is 0.11% and 0.11%, wetlands continued to increase by 0.07%; The carbon reserves of the study area in 2000, 2010 and 2020 were 24.26×108, 24.29×108, 24.27×108 t, showing a trend of first increasing and then decreasing.(2) Carbon storage reduced 3.19×105 t under natural development scenario. Under farmland protection scenario, ecological protection scenario, and farmland ecological joint protection scenario, their carbon sequestration will be respectively 4.29×106, 9.72×106, 9.60×106 t. [Conclusion] Reversing the increasing trend of unused land, continuing to steadily implement ecological protection policies with maintaining the cultivated land area, improving the carbon sequestration potential, and helping the Western Sichuan Plateau become an important “carbon sink” area should become the key points of land spatial planning and control on the Western Sichuan Plateau.

BACKGROUND With the increasing concern for food safety, especially for the elemental composition and efficacy of plant-derived foods and health products, research on the nutrient analysis of related foods is continuously carried out. At present, due to the wide variety of agricultural and health products, and the different environments in which the plant matrix grows, the elements absorbed by plants during the growth process vary greatly, making it difficult for many foods to meet the requirements of the calibration and testing system simply by using pure standards. It is necessary to combine the matrix reference materials for calibration and develop new plant-based reference materials. OBJECTIVES To improve the situation that there are few existing plant matrix reference materials, by developing 9 kinds of plant matrix reference materials for elemental analysis. Except for the reference materials for elemental analysis in notoginseng powder, all of them were developed for the first time, which supplemented the types of plant matrix elemental analysis reference materials and were mainly used in food nutrition and safety analysis and testing technology research of plant samples. METHODS In the early stage of development, the selection of candidate reference materials with the representative matrix were investigated and studied. The samples were pretreated, dried, crushed, sieved, and examined by a laser particle size analyzer before being packed in 45mL HDPE plastic bottles and inactivated by 60Co irradiation, which can be stored for a certain period of time. The samples were randomly selected from 30 bottles during the whole packing process, and the homogeneity test was performed by inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-optical emission spectrometry (ICP-OES), atomic fluorescence spectrometry (AFS) and volumetric method (VOL). The long-term stability of the reference materials under the specified storage conditions and the transport stability at 60℃ were investigated and the results were evaluated by trend analysis, which showed that the samples were stable under the specified conditions. The operation guideline of reference materials characterization analysis was developed, and 11 laboratories worked together to analyze 59 elements: Ag, Al, As, B, Ba, Be, Bi, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Gd, Ge, Hg, Ho, I, K, La, Li, Lu, Mg, Mn, Mo, N, Na, Nd, Ni, P, Pb, Pr, Rb, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Tb, Th, Ti, Tl, Tm, U, V, Y, Yb, Zn. RESULTS The data of the developed series of reference materials were statistically judged by Grubbs and Dixon and the suspicious values were rejected, with a rejection rate of less than 3%. Shapiro-Wilk was used to test the normality of the fixed value data, in which the element Ti in red bean, Bi, I and Th in needle mushroom, Ti in tremella, and I in jasmine had a skewed distribution of the original measurement data, and no certified value was taken only as the median value for reference, and the arithmetic mean of the customized data was used as the certified value for the remaining elements. The certified values and uncertainties of the nine reference materials were above 40, among which, 53 certified values and uncertainties were given for hawthorn and notoginseng. The uncertainty of reference materials consists of homogeneity uncertainty, stability uncertainty and characterization uncertainty. This series of reference materials was developed under the concept of metrological traceability, and a variety of quality control measures were taken to ensure the accuracy and reliability of analytical results and was applied as national level reference materials in 2021. The names and number are as follows: chemical composition of red bean (GBW10228), onion (GBW10232), rape (GBW10233), needle mushroom (GBW10247), tremella (GBW10248), root starch (GBW10249), hawthorn (GBW10250), notoginseng (GBW10251), and jasmine (GBW10234).The existing plant matrix elemental analysis reference materials are mostly found in rice, wheat, tea and other major agricultural and sideline food, and the certified value elements are mainly macronutrients and heavy metals. The present series of reference materials cover agricultural and health products with a large amount of daily sampling, except for notoginseng, which is developed for the first time, supplementing the variety of relevant quality control samples in the food testing field, with 59 certified value elements, which can effectively reflect the composition of elements in relevant products.In this study, more regionally representative candidates were selected, focusing on the beneficial nutritional elements K, Ca, Na, Mg, P, Zn, Fe and harmful metal elements As, Hg, Cd, Pb, whose contents can reflect the distribution characteristics of the elements in different samples and origins, such as red beans, which is a health food, and the candidates were picked from Yi'an County in Songnen Plain (one of the important commodity grain bases in China). It contains high contents of beneficial nutrients such as K (1.392g/100g), Ca (0.104g/100g), Mg (0.165g/100g), P (0.457g/100g), Zn (24μg/g) and Fe (71μg/g), and low contents of Pb (0.033μg/g), Cd (5.4ng/g) and other harmful metal elements, which are far below the national limit standards, reflecting the fertile black soil of Songnen Plain and the effectiveness of China's land management. For elements of Cd and Pb, red beans (5.4ng/g) and (0.033μg/g), onions (17ng/g) and (0.322μg/g), needle mushroom (33ng/g) and (0.126μg/g), rape (170ng/g) and (0.9μg/g), notoginseng (311ng/g) and (0.7μg/g), jasmine (420ng/g) and (1.65μg/g) form a gradient range, which is more applicable for food testing quality control. It can be found that the content of heavy metals in health products such as notoginseng and jasmine are higher than that in vegetable products such as rape and needle mushroom, which has a certain guidance for selecting suitable quality control samples in analytical testing. This is a guideline for the selection of suitable quality control samples.Due to the progress of the current testing methods and instruments, the precision of the data for the determination of rare earths and other elements with very low contents in some samples was good, and standard values were given, such as Eu (9.4±1.7ng/g), Ge (7.8±2.3ng/g), Lu (1.7±0.5ng/g), Tb (5.3±0.9ng/g), Tm (1.8±0.6ng/g) in rape, while the previous reference materials of similar vegetable matrixes did not reach such definite levels. CONCLUSIONS The development of the series of plant matrix reference materials is supplemental and improves the existing plant matrix reference materials, with obvious distribution characteristics of elements and wide applicability of the gradient range. This series of reference substances covers lots of elements with certified values, which is suitable for the quantity transfer and quality control of biological samples analysis and provides basis for the research on the correlation between the medicinal value and elements of health products.

In recent years, the Integrated Satellite Aerial Terrestrial (I‐SAT) network has garnered significant attention as an innovative and integrated communication system. However, it still encounters interference in the face of the complex external environment. In this context, reconfigurable intelligent surface (RIS) provides a key way of solving this problem and effectively improves the performance and stability of the I‐SAT network. This article considers the combination of unmanned aerial vehicle (UAV) and RIS and proposes a novel architecture for sub‐connected active RIS (ARIS) under the energy consumption constraints of UAV and ARIS. The authors first provide a UAV‐ARIS based position prediction strategy for the vehicle. Then, a joint RIS phase shift, amplification and UAV trail optimization algorithm is proposed to pursue a high achievable rate. The interference between each link and the total energy consumption are all taken into consideration. In addition, a deep deterministic policy gradient (DDPG) algorithm is utilized for the optimization problem, and achieves convergence in continuous action space. Finally, the simulation results affirm the precision of the proposed method in significantly enhancing performance compared to other schemes. [ABSTRACT FROM AUTHOR]

Based on the first‐principles calculation of density‐functional theory, the electronic structure and magnetic properties of hexagonal boron phosphide (h‐BP) with doping and applying strain to the transition‐metal (TM = Cr, Mn, Fe, Co, and Ni) elements are investigated. After the TM elements are introduced, the magnetism is induced. The magnetic moments are 3.00, 3.87, 1.00, 1.99, and 1.00 μB, respectively, which mainly contributed by the 3d orbitals of TM elements. In the case of magnetic coupling, Cr–Cr are mainly coupled antiferromagnetically at different distances. In addition, Fe–Fe performs a ferromagnetic state, and Co–Co represents an antiferromagnetic state with the distance of 3.213 Å. After applied strain, Co doped of the system shows the characteristics of semimetals under the application of 4% strain. It can be added that for h‐BP systems, doping Co and Mn increases its conductivity, which is beneficial to the study of spintronic materials. [ABSTRACT FROM AUTHOR]

In this study, we proposed the preparation of phosphate composite coatings (LSPCs) using a Fe3O4/hexagonal boron nitride (h-BN) hybrid, where the ordered dispersion and orientation of h-BN was achieved through a weak magnetic field. The evolution of the physiochemical structure of Fe3O4/h-BN before and after the modification was investigated by FTIR, XRD, XPS, TEM, SEM, and EDS. In addition, the corrosion protection performance of LSPCs was evaluated by electrochemical tests combining the analysis of the microstructure and phase characterization. Results indicate that the nano-Fe3O4 particles are successfully deposited on the surface of h-BN after modification. In addition, electrochemical results confirm that the corrosion protection performance of the layered phosphate composite coating is higher than that of the randomly dispersed coating. That is because the layered structure promotes the densification of the phosphate composite coating, thus delaying the permeation of corrosive media and makes the coatings more protective. [ABSTRACT FROM AUTHOR]