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Unique landslides (loess slide-flows) induced by an extreme rainstorm in 2018 on the Loess Plateau: A new geological hazard and erosion process

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International Journal of Sediment Research 2023年第2期38卷 228-239页

作者： Li Luo Wen-Zhao Guo Pei Tian Yi-li Liu Shao-Kun Wang Jia-Wei Luo State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau/College of Water Resources and Architectural Engineering Northwest Agriculture and Forestry University State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Key Laboratory for Geographical Process Analysis & Simulation of Hubei Province Central China Normal University

Currently, the vegetation has recovered well in most areas of the Loess Plateau in China, and soil erosion has significantly decreased. However, the heavy rainfall event in July 2018 triggered many instances of a unique type of loess landslides(i.e., slide-flows) on the gully-slopes with vegetation recovery in the Nanxiaohegou Basin on the Loess Plateau. This rainfall event was unusual and was a persistent heavy rainfall. The accumulated rainfall from 24 June to 10 July was 232.2 mm, which comprised 42% of the mean annual rainfall. A loess slide-flow is characterized by combining two movement types of the slide and flow. The loess slide-flows first slide on the gully-slopes and then turn into long run-out earthflows moving downstream, delivering vast amounts of sediment to the river. The average landslide erosion rates were 110.8-134.9 kg/m2. These loess slide-flows generally did not occur individually but in groups,which were characterized by large numbers, high density, small scale, and shallow depth. The changes of vegetation characteristics and soil characteristics both had a significant impact on the scale of the landslides. Grass with high coverage had an adverse effect on the occurrence of shallow landslides. The adverse hydrological effects of the plant may offset the weak root reinforcement. Loess slide-flows have become a new geological hazard and erosion process on the Loess Plateau. Loess slide-flows are a prominent ecological and environmental problem after vegetation restoration, and more attention should be paid to loess slide-flows in the future.

关键词： Loess plateau Landslide Soil erosion Vegetation Rainfall

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FairCF: fairness-aware collaborative filtering

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Science China(Information Sciences) 2022年第12期65卷 127-141页

作者： Pengyang shao Le WU Lei CHEN kun ZHANG Meng wang School of Computer Science and Information Engineering Hefei University of Technology Intelligent Interconnected Systems Laboratory of Anhui Province Institute of Artifcial Intelligence Hefei Comprehensive National Science Center

Collaborative filtering(CF) techniques learn user and item embeddings from user-item interaction behaviors, and are commonly used in recommendation systems to help users find potentially desirable items. Most CF models optimize recommendation accuracy; however, they may lead to unwanted biases for particular demographic groups. Thus, we focus on learning fair representations of CF-based recommendations. We formulate this problem as an optimization task with two competing goals: embedding representations better meet accuracy requirements of recommendations, and simultaneously obfuscate information hidden in the embedding space, which is related to the users’ sensitive attributes for fairness. Here,the intuitive idea is to use fair representation learning from machine learning to train a classifier with a sensitive attribute predictor from the user side to satisfy the fairness goal. However, such fair machine learning models assume entity independence, which differs greatly from CF because users and items are correlated collaboratively via user-item behaviors. Therefore, sensitive user information can be exposed from the users’ preferred items. Consequently, defining only fairness constraints on users cannot achieve fairness in recommendation systems. In this paper, we propose FairCF framework for fairness-aware collaborative filtering.In particular, we first define fairness constraints in a fair embedding space, where both a user classifier and an item classifier are employed to fit the fairness constraints. We then design an item classifier without item sensitive labels. The proposed framework can be trained in an end-to-end manner under most embedding based CF models. Extensive experiments conducted on three datasets(Movie Lens-100K, Movie Lens-1M,and Lastfm-360K) clearly demonstrate the superiority of the proposed FairCF framework relative to various fairness metrics(i.e., performance of newly-trained classifiers) than other state-of-the-art fairness-aware CF models with less than 4% accuracy reduction.

关键词： recommendation systems fairness adversarial learning

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Constrained future brightening of solar radiation and its implication for China's solar power

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National Science Review 2023年第1期10卷 154-165页

作者： Yanyi He kun Yang Martin Wild Kaicun wang Dan Tong Changkun shao Tianjun Zhou Department of Earth System Science Ministry of Education Key Laboratory for Earth System Modeling Institute for Global Change Studies Tsinghua University National Tibetan Plateau Data Center State Key Laboratory of Tibetan Plateau Earth System and Resource Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences Institute for Atmospheric and Climate Science ETH Zürich Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

As Earth’s primary energy source,surface downward solar radiation(Rs) determines the solar power potential and usage for climate change mitigation.Future projections of Rsbased on climate models have large uncertainties that interfere with the efficient deployment of solar energy to achieve China’ s carbon-neutrality goal.Here we assess 24 models in the latest Coupled Model Inter comparison Project Phase 6 with historical observations in China and find systematic biases in simulating historical Rsvalues likely due to model biases in cloud cover and clear-sky radiation,resulting in largely uncertain projections for future changes in Based on emergent constraints,we obtain credible Rswith narrowed uncertainties by ～56% in the mid-twenty-first century and show that the mean Rschange during 2050-2069 relative to 1995-2014 is 30% more brightening than the raw projections.Particularly in North China and Southeast China with higher power demand,the constrained projections present more significant brightening,highlighting the importance of considering the spatial changes in future Rswhen locating new solar energy infrastructures.

关键词： surface downward solar radiation CMIP6 model emergent constraint future change solar energy

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Direct conversion of CO_(2)to graphene via vapor–liquid reaction for magnesium matrix composites with structural and functional properties

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Journal of Magnesium and Alloys 2023年第4期11卷 1206-1212页

作者： Xuejian Li Xiaojun wang Xiaoshi Hu Chao Xu Wenzhu shao kun Wu State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001PR China National Key Laboratory of Precision Hot Processing of Metal Harbin Institute of TechnologyHarbin 150001PR China

Converting CO_(2)to valuable materials is attractive in environmental protection and resource utilization.In this study,a vapor-liquid interface reaction system for mass production of high-quality graphene is reported.The graphene obtained has high crystallinity and few defects during the reaction of CO_(2)and Mg melt.The growth mechanism of graphene is demonstrated in vapor-liquid interface area by combining the CO_(2)bubbles as a soft template to guide growth with the confinement effect of dense MgO nanoparticles.The quality of the graphene is verified by epoxy composites with high electromagnetic shielding effectiveness.Additionally,the V-L reaction method ingeniously solves the dispersion of graphene in metal,providing a preparation strategy of Mg matrix composites with structure and function integration.

关键词： Graphene Vapor-liquid interface Magnesiothermic reaction Dispersion Shielding effectiveness

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On the classification of mixed floating pollutants on the Yellow Sea of China by using a quad-polarized SAR image

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Frontiers of Earth Science 2018年第2期12卷 373-380页

作者： Xiaochen wang Yun shao Wei TIAN kun LI Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China Joint Institute for Regional Earth System Science and Engineering and Department of Atmospheric and Oceanic Sciences University of California Los Angeles CA 90095 USA

This study explored different methodologiesusing a C-band RADARSAT-2 quad-polarized SyntheticAperture Radar （SAR） image located over China＇s YellowSea to investigate polarization decomposition parametersfor identifying mixed floating pollutants from a complexocean background. It was found that solitary polarizationdecomposition did not meet the demand for detecting andclassifying multiple floating pollutants, even after applyinga polarized SAR image. Furthermore, considering thatYamaguchi decomposition is sensitive to vegetation andthe algal variety Enteromorpha prolifera, while H/A/alphadecomposition is sensitive to oil spills, a combination ofparameters which was deduced from these two decom-positions was proposed for marine environmental mon-itoring of mixed floating sea surface pollutants. Acombination of volume scattering, surface scattering, andscattering entropy was the best indicator for classifyingmixed floating pollutants from a complex ocean back-ground. The Kappa coefficients for Enteromorpha pro-lifera and oil spills were 0.7514 and 0.8470, respectively,evidence that the composite polarized parameters based onquad-polarized SAR imagery proposed in this research isan effective monitoring method for complex marinepollution.

关键词： RADARSAT-2 polarization decomposition mixed floating pollutants classification

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Changes in Florets’Vertical Direction within Inflorescence Affects Pollinator Behavior,and Fitness in Trifolium repens

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Phyton-International Journal of Experimental Botany 2022年第8期91卷 1617-1628页

作者： Qinzheng Hou Wenjuan shao Nurbiye Ehmet Taihong wang Yifan Xu kun Sun College of Life Sciences Northwest Normal UniversityLanzhou730070China

interactions,many flowers are known to display their attractive qualities,such as scent emission,flower rewards and floral vertical direction,in a rhythmic fashion.However,less is known about how plants regulate the relationship between these flower traits to adapt to pollinator visiting behavior and increase reproduction success.Here we investigated the adaptive significance of the flower bending from erect to downward in Trifolium repens.We observed the flowering dynamic characteristics(changes of vertical direction of florets,flowering number,pollen grain numbers,pollen viability and stigma receptivity over time after blossom)and the factors affecting the rate of flower bending in T.repens.Then we altered the vertical direction of florets in inflorescence of different types(upright and downward),and compared the pollinator behaviors and female reproductive success.Our results showed that florets opened sequentially in inflorescence,and then bend downwards slowly after flowering.The bending speed of florets was mainly influenced by pollination,and bending angle increased with the prolongation of flowering time,while the pollen germination rate,stigma receptivity and nectar secretion has a rhythm of“lowhigh-low”during the whole period with the time going.The visiting frequency of all the four species of pollinators on upward flowers was significantly higher than that of downward flowers,and they especially prefer to visit flowers with a bending angle of 30°–60°,when the flowers was exactly of the highest flower rewards(nectar secretion and number of pollen grains),stigma receptivity and pollen germination rate.The seed set ratio and fruit set ratio of upward flowers were significantly higher than downward flowers,but significantly lower than unmanipulated flowers.Our results indicated that the T.repens could increase female and male fitness by accurate pollination.The most suitable flower angle saves pollinators’visiting energy and enables them to obtain the highest nectar rewards.This coordination between plant

关键词： Trifolium repens floral vertical direction adaptive significances fitness

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Identification and functional analysis of arabinogalactan protein expressed in pear pollen tubes

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Journal of Integrative Agriculture 2023年第3期22卷 776-789页

作者： JIAO Hui-jun wang Hong-wei RAN kun DONG Xiao-chang DONG Ran WEI Shu-wei wang shao-min Shandong Institute of Pomology Tai’an 271000P.R.China

Arabinogalactan proteins(AGPs)are widely distributed in the plant kingdom and play a vital role during the process of plant sexual reproduction.In this study,we performed a comprehensive identification of the PbrAGPs expressed in pear pollen and further explored their influences on pollen tube growth.Among the 187 PbrAGPs that were found to be expressed in pear pollen tubes,38 PbrAGPs were specifically expressed in pollen according to the RNA-seq data.The PbrAGPs were divided into two groups of highly expressed and specifically expressed in pear pollen.We further tested their expression patterns using RT-PCR and RT-qPCR.Most of the PbrAGPs were expressed in multiple tissues and their expression levels were consistent with reads per kilobase per million map reads(RPKM)values during pollen tube growth,implying that PbrAGPs might be involved in the regulation of pear pollen tube growth.We also constructed phylogenetic trees to identify the functional genes in pear pollen tube growth.Therefore,19 PbrAGPs(PbrAGP1 to PbrAGP19)were selected to test their influences on pollen tube growth.Recombinant proteins of the 19 PbrAGP-His were purified and used to treat pear pollen,and 11 of the PbrAGP-His recombinant proteins could promote pear pollen tube growth.Additionally,pollen tube growth was inhibited when the expression levels of PbrAGP1 and PbrAGP5 were knocked down using an antisense oligonucleotide assay.PbrAGP1 and PbrAGP5 were localized in the plasma membrane and might not alter the distribution of pectin in the pollen tube.In summary,this study identified the PbrAGPs expressed in pear pollen and lays the foundation for further exploring their functions in pollen tube growth.

关键词： arabinogalactan proteins pear pollen tube antisense oligodeoxynucleotides sexual reproduction

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Systemic regulation of photosynthetic function in maize plants at graining stage under a vertically heterogeneous light environment

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Journal of Integrative Agriculture 2022年第3期21卷 666-676页

作者： WU Han-yu QIAO Mei-yu ZHANG wang-feng wang Ke-ru LI shao-kun JIANG Chuang-dao Key Laboratory of Plant Resources Institute of BotanyChinese Academy of SciencesBeijing 100093P.R.China Key Laboratory of Oasis Eco-Agriculture Xinjiang Production and Construction Corps/College of AgronomyShihezi UniversityShihezi 832003P.R.China Institute of Crop Sciences Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing 100081P.R.China

To cope with a highly heterogeneous light environment,photosynthesis in plants can be regulated systemically.Currently,the majority of studies are carried out with various plants during the vegetative growth period.As the reproductive sink improves photosynthesis,we wondered how photosynthesis is systemically regulated at the reproductive stage under a vertically heterogeneous light environment in the field.Therefore,changes of light intensity within canopy,chlorophyll content,gas exchange,and chlorophyll a fluorescence transient were carefully investigated at the graining stage of maize under various planting densities.In this study,a high planting density of maize drastically reduced the light intensities in the lower canopy,and increased the difference in vertical light distribution within the canopy.With the increase of vertical heterogeneity,chlorophyll content,light-saturated photosynthetic rate and the quantum yield of electron transport in the ear leaf(EL) and the fourth leaf below the ear(FLBE) were decreased gradually,and the ranges of declines in these parameters were larger at FLBE than those at EL.Leaves in the lower canopy were shaded artificially to further test these results.Partial shading(PS) resulted in a vertically heterogeneous light environment and enhanced the differences in photosynthetic characteristics between EL and FLBE.Removing the tassel and top leaves(RTL) not only improved the vertical light distribution within the canopy,but also reduced the differences in photosynthetic characteristics between the two leaves.Taken together,these results demonstrated that maize plants could enhance the vertical heterogeneity of their photosynthetic function to adapt to their light environment;slight changes of the photosynthetic function in EL at the graining stage under a vertically heterogeneous light environment indicated that the systemic regulation of photosynthesis is weak at the graining stage.

关键词： light environment photosynthesis gas exchange chlorophyll a fluorescence transient reproductive growth

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Current state and suggestions for mechanical harvesting of corn in China

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Journal of Integrative Agriculture 2022年第3期21卷 892-897页

作者： XIE Rui-zhi MING Bo GAO Shang wang Ke-ru HOU Peng LI shao-kun Institute of Crop Sciences Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Physiology and EcologyMinistry of Agriculture and Rural AffairsBeijing 100081P.R.China

Corn(Zea mays L.) accounts for the largest shares of planting area and total yield of grain crops in China.Corn production has played a significant role in the country’s development of agriculture and national economy.Harvesting requires the largest amount of manual labor in the entire corn production process,accounting for about 50–60% of the total labor input.

关键词： China crops harvesting

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A Bilayer High-Temperature Dielectric Film with Superior Breakdown Strength and Energy Storage Density

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Nano-Micro Letters 2023年第9期15卷 479-491页

作者： Jiang-Bo Ping Qi-kun Feng Yong-Xin Zhang Xin-Jie wang Lei Huang shao-Long Zhong Zhi-Min Dang State Key Laboratory of Power System Department of Electrical EngineeringTsinghua UniversityBeijing 100084People’s Republic of China

The further electrification of various fields in production and daily life makes it a topic worthy of exploration to improve the performance of capacitors for a long time,including thin-film capacitors.The discharge energy density of thin-film capacitors that serves as one of the important types directly depends on electric field strength and the dielectric constant of the insulation material.However,it has long been a great challenge to improve the breakdown strength and dielectric constant simultaneously.Considering that boron nitride nanosheets(BNNS)possess superior insulation and thermal conductivity owing to wide band gap and 2-dimensional structure,a bilayer polymer film is prepared via coating BNNS by solution casting on surface of polyethylene terephthalate(PET)films.By revealing the bandgap and insulating behavior with UV absorption spectrum,leakage current,and finite element calculation,it is manifested that nanocoating contributes to enhance the bandgap of polymer films,thereby suppressing the charge injection by redirecting their transport from electrodes.Worthy to note that an ultrahigh breakdown field strength(~736 MV m^(−1)),an excellent discharge energy density(~8.77 J cm^(−3))and a prominent charge-discharge efficiency(~96.51%)are achieved concurrently,which is ascribed to the contribution of BNNS ultrathin layer.In addition,the modified PET films also have superior comprehensive performance at high temperatures(~120°C).The materials and methods here selected are easily accessible and facile,which are suitable for large-scale roll-to-roll process production,and are of certain significance to explore the methods about film modification suitable for commercial promotion.

关键词： Film capacitor Dielectric property Boron nitride nanosheets Surface coating Energy storage characteristics

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