Mapping upland crop–rice cropping systems for targeted sustainable intensification in South China

Upland crop-rice cropping systems(UCR)facilitate sustainable agricultural intensification.Accurate UCR cultivation mapping is needed to ensure food security,sustainable water management,and rural revitalization.However,datasets describing cropping systems are limited in spatial coverage and crop types.Mapping UCR is more challenging than crop identification and most existing approaches rely heavily on accurate phenology calendars and representative training samples,which limits its applications over large regions.We describe a novel algorithm(RRSS)for automatic mapping of upland crop-rice cropping systems using Sentinel-1 Synthetic Aperture Radar(SAR)and Sentinel-2 Multispectral Instrument(MSI)data.One indicator,the VV backscatter range,was proposed to discriminate UCR and another two indicators were designed by coupling greenness and pigment indices to further discriminate tobacco or oilseed UCR.The RRSS algorithm was applied to South China characterized by complex smallholder rice cropping systems and diverse topographic conditions.This study developed 10-m UCR maps of a major rice bowl in South China,the Xiang-Gan-Min(XGM)region.The performance of the RRSS algorithm was validated based on 5197 ground-truth reference sites,with an overall accuracy of 91.92%.There were7348 km^(2) areas of UCR,roughly one-half of them located in plains.The UCR was represented mainly by oilseed-UCR and tobacco-UCR,which contributed respectively 69%and 15%of UCR area.UCR patterns accounted for only one-tenth of rice production,which can be tripled by intensification from single rice cropping.Application to complex and fragmented subtropical regions suggested the spatiotemporal robustness of the RRSS algorithm,which could be further applied to generate 10-m UCR datasets for application at national or global scales.

Review on the nanoparticle fluidization science and technology

Gas fluidization has an ability to turn static particles to fluid-like dense flow, which allows greatly improved heat transfer among porous powders and highly efficient solid processing to become reality. As the rising star of current scientific research, some nanoparticles can also be fluidized in the form of agglomerates, with sizes ranging from tens to hundreds of microns. Herein, we have reviewed the recent progress on nanomaterial agglomeration and their fluidization behavior, the assisted techniques to enhance the fluidization of nanomaterials,including some mechanical measures, external fields and improved gas injections, as well as their effects on solid fluidization and mixing behaviors. Most of these techniques are effective in breaking large agglomerates and promoting particulate fluidization, meanwhile, the solid mixing is intensified under assisted fluidization. The applications of nanofluidization in nanostructured material production and sustainable chemical industry are further presented. In summary, the fluidization science of multidimensional, multicomponent and multifunctional particles, their multi-phase characterization, and the guideline of fluidized bed coupled process are prerequisites for the sustainable development of fluidized bed based materials, energy and chemical industry.

Identification and analysis of AP2/ERF gene family in tomato underabiotic stress

AP2/ERE-type transcription factors,as a type of plant-specific transcription factors,play a key role in plant biotic and abiotic stress.Meanwhile,they have been studied in many plants,but rarely in tomatoes.In this study,we performed a genome-wide analysis of the SlAP2/ERF gene family of tomato,and finally identified 29 SlAP2/ERF genes and divided them into different subfamilies.At the same time,its basic physical and chemical properties were analyzed.We also constructed phylogenetic trees with 30 Arabidopsis AP2/ERF proteins and 28 potatoes AP2/ERF proteins to ensure conservative homology between them.In addition,we mapped 29 SlAP2/ERF transcription factors on 10 different chromosomes,and identified 43 responsive plant hormones,responsive light signals,tissue-specific expression and stress response elements from 2000bp upstream of the promoter region,and we analyzed conserved motifs and gene structures of SlAP2/ERF.The tertiary structure of SlAP2/ERF protein was constructed by homology modeling,and the protein-protein interaction network was constructed based on Arabidopsis Thaliana.Finally,the expression pattern of tomato in different tissues was studied by using gene expression database,and the expression level of tomato under abiotic stress was detected by q-RT-PCR.These results provide comprehensive information for further study of the function of the SlAP2/ERF gene family.

《中国多民族青少年文化认同问卷》在内蒙古地区大学生中的适用性检验

本文使用《中国多民族青少年文化认同问卷》对内蒙古地区的523名大学生进行调查,采用相关分析、内部一致性检验和验证性因素分析进行信度、效度检验,并检验内蒙古地区大学生的文化认同情况。结果表明,该问卷的内部一致性信度、结构效度均符合心理测量学标准,效标关联效度较好。该问卷在内蒙古地区的使用倾向于是一个一阶六因素结构。内蒙古地区大学生文化认同总体情况较好,整合认同模式的被试人数最多。性别、生源地和民族对于内蒙古地区大学生文化认同情况具有一定的影响。

Elucidating the effect of barium halide promoters on La_(2)O_(3)/CaO catalyst for oxidative coupling of methane

The industrialization of oxidative coupling of methane(OCM)is restricted by the low once through yield of C_(2)hydrocarbons.Recently,the halogen-assisted OCM process has been attempted to overcome this issue,but the reaction stability was poor due to the rapid loss of gas-phase halides or molten alkali halides.In this work,the barium salts,particularly barium halides(BaCl_(2)and BaF_(2)),were demonstrated to be efficient promoters to improve the OCM reactivity of La_(2)O_(3)/CaO catalyst by increasing both C_(2)selectivity and C_(2)H_(4)/C_(2)H_(6)ratio,and simultaneously achieving outstanding reaction stability.The promoting mechanism can be understood in two aspects.On the one hand,the introduction of barium salts increased the amount of surface electrophilic oxygen species,serving as the alkaline active sites for selective methane activation.On the other hand,the barium halide additives induced the in-situ formation of methyl halide intermediates facilitating C_(2)H_(6)dehydrogenation,and their intimate contact with catalyst substrate restricted the rapid halogen loss and thereby improved the catalytic stability.This work not only provides a class of efficient OCM catalyst,but also offers a highly stable halogen-assisted reaction strategy.

An Improved Non-Parametric Method for Multiple Moving Objects Detection in the Markov Random Field

Detecting moving objects in the stationary background is an important problem in visual surveillance systems.However,the traditional background subtraction method fails when the background is not completely stationary and involves certain dynamic changes.In this paper,according to the basic steps of the background subtraction method,a novel non-parametric moving object detection method is proposed based on an improved ant colony algorithm by using the Markov random field.Concretely,the contributions are as follows:1)A new nonparametric strategy is utilized to model the background,based on an improved kernel density estimation;this approach uses an adaptive bandwidth,and the fused features combine the colours,gradients and positions.2)A Markov random field method based on this adaptive background model via the constraint of the spatial context is proposed to extract objects.3)The posterior function is maximized efficiently by using an improved ant colony system algorithm.Extensive experiments show that the proposed method demonstrates a better performance than many existing state-of-the-art methods.

3D Physical Simulation of Water Flooding Characteristics of Buried Hill Reservoir with Different Fracture Systems

In order to understand the water-flooding characteristics of different fracture systems in metamorphic rock buried hill reservoirs and the mechanism of improving water-flooding development effect, a three-dimensional physical model of fractured reservoirs is established according to the similarity criterion based on the prototype of metamorphic buried hill reservoirs in JZ Oilfield in Bohai Bay Basin. Combined with the fractured reservoir characteristics of JZ Oilfield, the water displacement characteristics of the top-bottom staggered injection-production well pattern in different fracture network mode and different fracture development degree of buried hill reservoir are studied. The experimental results show that: 1) the more serious the fracture system irregularity is, the shorter the water-free oil production period is and the lower the water-free oil recovery is. After water breakthrough of production wells, the water cut rises faster, and the effect of water flooding development is worse;2) under the condition of non-uniform fracture development, the development effect of the bottom fracture undeveloped is better than that of the middle fracture undeveloped. Water injection wells are deployed in areas with relatively few fractures, while oil wells are deployed in fractured areas with higher oil recovery and better development effect.

董事高管责任保险会诱发企业真实盈余管理吗?

本文以2010~2019年沪深A股上市公司为样本,实证检验了董事高管责任保险的引入对上市公司真实盈余管理的影响及其作用机制。研究发现,董事高管责任保险与真实盈余管理正相关,说明董事高管责任保险助长了高管的机会主义行为;董事高管责任保险的"兜底"效应诱发高管更多的冒进行为,提高了企业风险承担水平,进而加剧了真实盈余管理,即风险承担在二者之间发挥中介效应。通过拓展性研究发现,在民营企业及外部审计规模较小的情景下,董事高管责任保险与公司真实盈余管理之间的相关性更强。本文研究加深了资本市场对董事高管责任保险治理效应的认知,对相关法律法规的健全及监管部门的发展具有一定的参考意义。

Remaining Oil Distribution Law and Potential Tapping Strategy of Horizontal Well Pattern in Narrow Oil Rim Reservoir with Gas Cap and Edge Water

For thin oil rim reservoir with gas cap and edge water, it is helpful to improve the development effect to find out the distribution law of remaining oil in this kind of reservoirs. For this reason, taking the narrow oil rim reservoir with gas cap and edge water of Oilfield A in Bohai Sea as a case, the main controlling factors, including reservoir structure, fault, gas cap energy, edge water energy and well pattern, affecting the distribution of residual oil in this kind of reservoir were analyzed by using the data of core, logging, paleogeomorphology and production. Then, the distribution law of remaining oil was summarized. Generally, the remaining oil distribution is mainly potato-shaped or strip-shaped in plane. Vertically, it depends on the energy of gas cap and edge water. For the reservoir with big gas gap and weak edge water, the remaining oil mainly lies in the bottom of oil column. And for the reservoir with small gas gap and strong edge water, the remaining oil mainly locates at the top of oil column. Aiming at different distribution modes of remaining oil, the corresponding potential tapping strategies of horizontal wells are put forward: in the late stage of development, for the reservoir with big gas gap and weak edge water, the remaining oil concentrates at the bottom of the oil column, and the position of horizontal well should be placed at the lower 1/3 to the lower 1/5 of the oil column;for the reservoir with small gas cap and strong edge water, the remaining oil locates at the top of the oil column, and the position of horizontal well should be put at the upper 1/5 to the upper 1/3 of the oil column height, vertically. Based on the study on remaining oil of Oilfield A, a potential tapping strategy of well pattern thickening and vertical position optimization of horizontal well was proposed. This strategy guided the efficient implementation of the comprehensive adjustment plan of the oilfield. Moreover, 18 infill development wells were implemented in Oilfield A, and the average production of the infill wells is 2.1 times that of the surrounding old wells. It is estimated that the ultimate recovery factor of the oilfield will reach 33.9%, which is 2.3% higher than that before infilling wells. This study can be used for reference in the development of similar reservoirs.

Research on Optimization of Reservoir Perforation Position in Offshore Polymer Flooding Oilfield

In order to enhance the effect of polymer flooding in offshore oilfields, so as to realize the longer stable production period and higher oil recovery, the reservoir perforation positions of production wells and injection wells are taken as research objects. By analyzing the distribution of remaining oil and production characteristics under different perforation positions, the optimum perforation positions of production wells and injection wells are selected. Bohai oilfield L was taken as target oilfield in this article, according to the actual reservoir characteristic parameters, three-dimensional laboratory physical simulation experiments of water flooding and polymer flooding were carried out, the experiments include different perforation positions of production wells and injection wells. The research result showed that the influence of perforation position on residual oil and development characteristics of the model is obvious. When takes the scheme of injection well upper part perforated and production well all part perforated, the least of the remaining oil distribution, the longest of the production period without water. Contrast with other perforation schemes, its stable production period increase about 1.2 times, the oil recovery of water flooding increase 3.7% - 6.0%, the oil recovery of polymer flooding increase 2.5% - 4.1%. So it is recommended as the best perforation scheme. Preferable effect had been achieved when translating research findings into practice. It can serve as a reference to the similar offshore oilfield.

Research and Application of Water Flooding Timing and Method for Blocky Bottom Water Fractured Buried Hill Reservoir

Oilfield A is a fractured buried hill reservoir in Bohai bay of China. In order to solve the difficult problem of water flooding timing and method in oilfield. Considering the characteristics of the buried hill fractures with stress sensitivity and strong heterogeneity, the ECLIPSE software was used in the research, and a three-dimensional injection-production numerical model for horizontal wells in buried hill reservoirs is established. According to the main research factors in water flooding, a series of water flooding schemes are designed, and the optimization of water flooding timing, oil recovery rate and water flooding mode in buried hill reservoirs were carried out. The results show that the optimum pressure level of fractured reservoir is about 70% of the original reservoir pressure. The optimal water flooding method is the conventional water flooding in the initial stage, when the water cut reaches 80%, it is converted into periodic water flooding. The oil recovery is the highest when the water injection period is 4 months. Field tests show that conventional water flooding is carried out in the initial stage of the oilfield A when the pressure is reduced to 70% of the original. Periodic water flooding is carried out when water cut is 80%. Good development results had been achieved in the 10 years since oilfield A was put into production. The average productivity of single well reached 300 m3/d in the initial stage, at present, the water cut is 60%, and the recovery degree is 18.5%, which is better than that of similar oilfields. This technology improves the water flooding effect of blocky bottom water fractured dual media reservoirs in metamorphic buried hills, and provides a reference for the development of similar reservoirs.

内蒙古地区蒙、汉大学生文化认同对主观幸福感的影响:自我建构的中介作用

目的:探讨大学生的文化认同、自我建构对其主观幸福感的影响。方法:以内蒙古地区4所高校的523名蒙古族和汉族大学生为研究对象,进行问卷调查。结果:大学生的文化认同和自我建构与主观幸福感存在显著的正相关,其中文化认同可以直接预测主观幸福感,也可以通过自我建构中的个体我和集体我间接预测主观幸福感。结论:大学生的自我建构在文化认同对主观幸福感的作用中起到部分中介作用。

Covalent-architected molybdenum disulfide arrays on Ti_(3)C_(2)T_(x) MXene fiber towards robust capacitive energy storage

Ti_(3)C_(2)T_(x)MXene fiber has shown extraordinary potential for supercapacitor electrode in wearable elec-tronics and textile energy storage,but realizing high energy density and practical-powered applications remains a great challenge.Here,we report a covalent-architected molybdenum disulfide-Ti_(3)C_(2)T_(x)(MoS_(2)-Ti_(3)C_(2)T_(x))core-shell fiber for high-performance supercapacitor.Benefiting from the microfluidic and micro-reaction strategies,the ordered MoS_(2)arrays are strongly bridged on Ti_(3)C_(2)T_(x)fiber via Ti-O-Mo bond,re-sulting in large exposed surface,enhanced porosity and excellent interfacial conduction for charges high diffusion and faradaic transfer.The MoS_(2)-Ti_(3)C_(2)T_(x)fiber exhibits ultra-large capacitance of 2028 F cm^(-3)and admirable reversibility in 1 M H_(2)SO_(4)aqueous electrolyte.Meanwhile,MoS_(2)-Ti_(3)C_(2)T_(x)fiber-based solid-state supercapacitor presents high energy density of 23.86 mWh cm^(-3),capacitance of 1073.6 F cm^(-3)and superior cycling ability of 92.13%retention after 20,000 cycles,which can realize stable energy supply for wearable watch,LEDs,electric fans,toy ship and self-powered devices.Our work may provide an insight-ful guidance for the advanced design of structural fiber towards robust new energy and next-generation wearable industry.

The influence of the capping ligands on the optoelectronic performance,morphology,and ion liberation of CsPbBr_(3)perovskite quantum dots

Perovskite quantum dots(PeQDs)endowed with capping ligands exhibit impressive optoelectronic properties and enable for costefficient solution processing and exciting application opportunities.We synthesize and characterize three different PeQDs with the same cubic CsPbBr_(3)core,but which are distinguished by the ligand composition and density.PeQD-1 features a binary didodecyldimethylammonium bromide(DDAB)and octanoic acid capping ligand system,with a high surface density of 1.53 nm^(-2),whereas PeQD-2 and PeQD-3 are coated by solely DDAB at a gradually lower surface density.We show that PeQD-1 endowed with highest ligand density features the highest dispersibility in toluene of 150 g/L,the highest photoluminescence quantum yield of 95%in dilute solution and 59%in a neat film,and the largest core-to-core spacing in neat thin films.We further establish that ions are released from the core of PeQD-1 when it is exposed to an electric field,although it comprises a dense coating of one capping ligand per four surface core atoms.We finally exploit these combined findings to the development of a light-emitting electrochemical cell(LEC),where the active layer is composed solely of solution-processed pure PeQDs,without additional electrolytes.In this device,the ion release is utilized as an advantage for the electrochemical doping process and efficient emissive operation of the LEC.

The stabilization effect of Al_(2)O_(3)on unconventional Pb/SiO_(2)catalyst for propane dehydrogenation

Similar to Sn,Pb located at the same group(IVA)in the periodic table of elements,can also catalyze propane dehydrogenation to propene,while a fast deactivation can be observed.To enhance the stability,the traditional carrier Al_(2)O_(3)with a small amount,was introduced into Pb/SiO_(2)catalyst in this study.It has been proved that Al_(2)O_(3)can inhibit the reduction of PbO,and weaken the agglomeration and loss of Pb species due to its enhanced interaction with Pb species.As a result,3Al15Pb/SiO_(2)catalyst exhibits a much higher stability up to more than 150 h.In addition,a simple schematic diagram of the change of surface species on the catalyst surface after Al_(2)O_(3)addition was also proposed.

Anthrazoline Photocatalyst for Promoting Esterification and Etherification Reactions via Photoredox/Nickel Dual Catalysis

Here,we demonstrate a readily prepared anthrazoline photocatalyst,which can effectively promote C—O bond formation reactions with the aid of Ni(II)complex.This methodology enables the esterification(36 examples)and etherification(8 examples)with a broad range of scope,allowing aryl and alkyl halides coupled with diverse carboxylic acids/alcohols.Our metal-free photocatalysts have a potential broad application,may serve as an alternative to some iridium and ruthenium based photocatalysts,and are of potential importance to the pharmaceutical industry.

Interactive effects of understory removal and fertilization on soil respiration in subtropical Eucalyptus plantations

Aims It has been well recognized that understory vegetation plays an important role in driving forest ecosystem processes and functioning.In subtropical plantation forests,understory removal and fertiliza-tion have been widely applied;however,our understanding on how understory removal affects soil respiration and how the process is regulated by fertilization is limited.Here,we conducted an under-story removal experiment combined with fertilization to evaluate the effects of the two forest management practices and their inter-actions on soil respiration in subtropical forest in southern China.Methods The study was conducted in a split-plot design with fertilization as the whole-plot factor,understory removal as the subplot factor and block as the random factor in subtropical Eucalyptus plantations.In total,there were four treatments:control with unfertilized and intact understory(CK),understory removal but without fertilization(UR),with fertilization but without understory removal(FT)and with fertilization+understory removal(FT+UR).Eucalyptus above-and belowground biomass increment,fine root biomass,soil tempera-ture,soil moisture and soil respiration were measured in the present study.understory respiration(Ru)was quantified in different ways:Ru=RCK−Ru or Ru=RFT−R(FT+u);fertilization increased soil respiration(RFI)was also quantified in different ways:RFI=RFT−RCK or RFI=R(FT+u)−Ru.Important Findingsover a 2-year experiment,our data indicate that understory removal significantly decreased soil respiration,while fertilization increased soil respiration.understory removal decreased soil respiration by 28.8%under fertilization,but only 15.2%without fertilization.Fertilization significantly increased soil respiration by 23.6%with the presence of understory vegetation,and only increased by 3.7%when understory was removed,indicating that fertilization increased soil respiration mainly by increasing the contribution of the understory.our study advances our understanding of the interactive effects of understory management and fertilization on soil respiration in subtropical plantations.

Recent advances in organic-based materials for resistive memory applications

With the rapid development of data-driven human interaction,advanced datastorage technologies with lower power consumption,larger storage capacity,faster switching speed,and higher integration density have become the goals of future memory electronics.Nevertheless,the physical limitations of conventional Si-based binary storage systems lag far behind the ultrahigh-density requirements of post-Moore information storage.In this regard,the pursuit of alternatives and/or supplements to the existing storage technology has come to the forefront.Recently,organic-based resistive memory materials have emerged as promising candidates for next-generation information storage applications,which provide new possibilities of realizing high-performance organic electronics.Herein,the memory device structure,switching types,mechanisms,and recent advances in organic resistive memory materials are reviewed.In particular,their potential of fulfilling multilevel storage is summarized.Besides,the present challenges and future prospects confronted by organic resistive memory materials and devices are discussed.

Flow dynamics and contact efficiency in a novel fast-turbulent fluidized bed with ring-feeder internals

The flow dynamics in a novel fast-turbulent fluidized bed （FTFB） with middle-upper expanding structure and two different ring-feeder internals （mixed and vortex ring-feeder） were studied to achieve a reduction in gasoline olefin production, Compared with a conventional circulating fluidized bed, the novel FTFB displayed unique characteristics and advantages. A higher solids holdup and more uniform solids holdup distribution existed in the diameter-expanding region, especially for the FTFB with vortex ring-feeder structure, A probability density distribution analysis indicated that the novel fluidized bed could reduce gas-solids segregation and enhance gas-solids interaction. A constant carbon dioxide tracer system was used to simulate the reactant gas distribution. The gas-solids contact efficiency was defined according to the solid dispersibility and the amount of gas covering the solid surface. Novel FTFB risers, especially those with vortex ring-feeders, have a much higher gas-solids contact efficiency than that of traditional risers.

The deubiquitinase USP11 promotes ovarian cancer chemoresistance by stabilizing BIP

Dear Editor,Chemoresistance is a major problem in the treatment of ovarian cancer patients and leads to poor prognosis,but its underlying mechanism remains elusive.Accumulating evidences have found that the aberrant regulation of the protein ubiquitination pathway plays an essential role in ovarian cancer chemoresistance.13 However,it is unclear whether and how deubiquitinase-USP11 involves in ovarian cancer chemoresistance.