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Flow-slide characteristics and failure mechanism of shallow landslides in granite residual soil under heavy rainfall

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Journal of Mountain Science 2022年第6期19卷 1541-1557页

作者： BAI Hui-lin FENG Wen-kai LI Shuang-quan YE Long-zhen WU Zhong-teng HU Rui dai hong-chuan HU Yun-peng YI Xiao-yu DENG Peng-cheng State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China Key Laboratory of Geohazard Prevention of Hilly Mountainous Ministry of Natural ResourcesFuzhou 350002China Fujian Key Laboratory ofGeohazard Prevention Fuzhou 350002China

Affected by typhoons over years, Fujian Province in Southeast China has developed a large number of shallow landslides, causing a long-term concern for the local government. The study on shallow landslide is not only helpful to the local government in disaster prevention, but also the theoretical basis of regional early warning technology. To determine the whole-process characteristics and failure mechanisms of flow-slide failure of granite residual soil slopes, we conducted a detailed hazard investigation in Minqing County, Fujian Province, which was impacted by Typhoon Lupit-induced heavy rainfall in August 2021. Based on the investigation and preliminary analysis results, we conducted indoor artificial rainfall physical model tests and obtained the whole-process characteristics of flow-slide failure of granite residual soil landslides. Under the action of heavy rainfall, a granite residual soil slope experiences initial deformation at the slope toe and exhibits development characteristics of continuous traction deformation toward the middle and upper parts of the slope. The critical volumetric water content during slope failure is approximately 53%. Granite residual soil is in a state of high volumetric water content under heavy rainfall conditions, and the shear strength decreases, resulting in a decrease in stability and finally failure occurrence. The new free face generated after failure constitutes an adverse condition for continued traction deformation and failure. As the soil permeability(cm/h) is less than the rainfall intensity(mm/h), and it is difficult for rainwater to continuously infiltrate in short-term rainfall, the influence depth of heavy rainfall is limited. The load of loose deposits at the slope foot also limits the development of deep deformation and failure. With the continuous effect of heavy rainfall, the surface runoff increases gradually, and the influence mode changes from instability failure caused by rainfall infiltration to erosion a

关键词： Granite residual soil Flow slide process Failure mechanism Artificial rainfall Critical volumetric water content

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Grain refinement of 5A06 aluminum alloy welds caused by tungsten inert gas welding arc characteristics under Ar-He alternating gas supply conditions:a coupled method of water-cooled copper plate test/numerical simulation

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Journal of Iron and Steel Research International 2024年第3期31卷 767-777页

作者： hong-bin dai Jian Miao Jia-xin Lin School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040HeilongjiangChina

The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and *** the tungsten inert gas(TIG)welding process under the condition of Ar-He alternating gas supply,the arc is alternately converted between Ar arc and He arc with an alternating gas supply cycle,which has obvious arc change *** FLUENT software was used to numerically simulate the characteristics of the TIG arc under the condition of alternating gas supply,and the arc temperature field,arc pressure,electric potential and current density distribution under the condition of alternating gas supply were *** with the real-time data of arc pressure measured by the water-cooled copper plate with holes,it is proved that the TIG arc has obvious dynamic characteristics under the condition of Ar-He alternating gas *** unique dynamic TIG arc acts on the 5A06 aluminum alloy weld,causing the molten pool to stir,resulting in uniform microstructure and grain refinement at the weld,and thereby improving the mechanical properties of the welded joint.

关键词： Alternating gas supply Grain refinement Numerical simulation Tungsten argon arc morphology Microstructure Mechanical property

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The Rate of Convergence of Augmented Lagrangian Method for Minimax Optimization Problems with Equality Constraints

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Journal of the Operations Research Society of China 2024年第2期12卷 265-297页

作者： Yu-hong dai Li-Wei Zhang LSEC ICMSECAMSSChinese Academy of SciencesBeijing 100190China Institute of Operations Research and Control Theory School of Mathematical SciencesDalian University of TechnologyDalian 116024China

The augmented Lagrangian function and the corresponding augmented Lagrangian method are constructed for solving a class of minimax optimization problems with equality *** prove that,under the linear independence constraint qualification and the second-order sufficiency optimality condition for the lower level problem and the second-order sufficiency optimality condition for the minimax problem,for a given multiplier vectorμ,the rate of convergence of the augmented Lagrangian method is linear with respect to||μu-μ^(*)||and the ratio constant is proportional to 1/c when the ratio|μ-μ^(*)||/c is small enough,where c is the penalty parameter that exceeds a threshold c_(*)>O andμ^(*)is the multiplier corresponding to a local ***,we prove that the sequence of multiplier vectors generated by the augmented Lagrangian method has at least Q-linear convergence if the sequence of penalty parameters(ck)is bounded and the convergence rate is superlinear if(ck)is increasing to ***,we use a direct way to establish the rate of convergence of the augmented Lagrangian method for the minimax problem with a quadratic objective function and linear equality constraints.

关键词： Minimax optimization Augmented Lagrangian method Rate of convergence Second-order sufficiency optimality

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Strong evidence for latitudinal diversity gradient in mosses across the world

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Plant Diversity 2024年第4期46卷 537-541页

作者： hong Qian Zun dai Jian Wang Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA Bryology Laboratory School of Life SciencesEast China Normal UniversityShanghai 200241China Shanghai Institute of Eco-Chongming(SIEC) 3663 Northern Zhongshan RoadShanghai 200062China

Species richness generally decreases with increasing latitude,a biodiversity gradient that has long been considered as one of the few laws in *** latitudinal diversity gradient has been observed in many major groups of *** plants,the latitudinal diversity gradient has been observed in vascular plants,angiosperms,ferns,and ***,a conspicuous latitudinal diversity gradient in mosses at a global or continental scale has not been observed until ***,we analyze a comprehensive data set including moss species in each band of 20° in latitude *** results show that moss species richness decreases strongly with increasing latitude,regardless of whether the globe is considered as a whole or different longitudinal segments(e.g.,Old World versus New World) are considered *** result holds when variation in area size among latitudinal bands is taken into ***'s correlation coefficient between latitude and species richness is-0.99 for both the Northern and Southern *** bryophytes are an extant lineage of early land plants and because mosses not only include most of extant species of bryophytes but also are important constituents of most terrestrial ecosystems,understanding geographic patterns of mosses is particularly important The finding of our study fills a critical knowledge gap.

关键词： Bryophyte Latitudinal diversity gradient Moss Species density Species diversity

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Metagenomics reveals the microbial community and functional metabolism variation in the partial nitritation-anammox process:From collapse to recovery

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Journal of Environmental Sciences 2024年第1期135卷 210-221页

作者： hong Wang Hui Gong Xiaohu dai Min Yang State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China BIOMATH Department of Data Analysis and Mathematical ModellingGhent UniversityGhent 9000Belgium

Mainstream partial nitritation-anammox(PNA)process easily suffers from performance instability and even reactor collapse in ***,it is of great significance to unveil the characteristic of performance recovery,understand the intrinsic mechanism and then propose operational *** this study,we combined long-term reactor operation,batch tests,and metagenomics to reveal the succession of microbial community and functional metabolism variation from system collapse to *** aeration control(0.10-0.25mg O_(2)/L)was critical for performance *** was also found that Candidatus Brocadia became the dominant flora and its abundance increased from 3.5%to 11.0%.Significant enhancements in carbon metabolism and phospholipid biosynthesis were observed during system recovery,and the genes abundance related to signal transduction was dramatically *** up-regulation of sdh and suc genes showed the processes of succinate dehydrogenation and succinyl-CoA synthesis might stimulate the production of amino acids and the synthesis of proteins,thereby possibly improving the activity and abundance of AnAOB,which was conducive to the performance ***,the increase in abundance of hzs and hdh genes suggested the enhancement of the anammox *** in the abundance of key genes involved in nitrogen metabolism indicated that nitrogen removal pathway was more diverse after system *** achievement of performance recovery was driven by anammox,nitrification and denitrification coupled with dissimilatory nitrate reduction to *** results provide deeper insights into the recovery mechanism of PNA system and also provide a potential regulation strategy for the stable operation of the mainstream PNA process.

关键词： Partial nitritation-anammox Metagenomics Microbial community Functional metabolism Recovery

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An Accelerated Proximal Gradient Algorithm for Hankel Tensor Completion

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Journal of the Operations Research Society of China 2024年第2期12卷 461-477页

作者： chuan-Long Wang Xiong-Wei Guo Xi-hong Yan Key Laboratory of Engineering and Computational Science Shanxi Provincial Department of EducationJinzhong 030619ShanxiChina Department of Mathematics Taiyuan Normal UniversityJinzhong 030619ShanxiChina

In this paper,an accelerated proximal gradient algorithm is proposed for Hankel tensor completion *** our method,the iterative completion tensors generated by the new algorithm keep Hankel structure based on projection on the Hankel tensor ***,due to the special properties of Hankel structure,using the fast singular value thresholding operator of the mode-s unfolding of a Hankel tensor can decrease the computational ***,the convergence of the new algorithm is discussed under some reasonable ***,the numerical experiments show the effectiveness of the proposed algorithm.

关键词： Hankel tensor Tensor completion Accelerated proximal gradient algorithm

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Research on casing deformation prevention technology based on cementing slurry system optimization

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Petroleum Science 2024年第2期21卷 1231-1240页

作者： Yan Yan Meng Cai Wen-Hai Ma Xiao-chuan Zhang Li-hong Han Yong-hong Liu State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials CNPC Tubular Goods Research InstituteXi©an710077ShaanxiChina College of Mechanical and Electrical Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Gas Evaluation and Exploitation Key Laboratory of Sichuan Province Chengdu610095SichuanChina CNPC Daqing Oilfield Company Daqing163453HeilongjiangChina

The casing deformation prevention technology based on the optimization of cement slurry is proposed to reduce the casing deformation of shale oil and gas wells during hydraulic fracturing. In this paper, the fracture mechanism of hollow particles in cement sheath was firstly analyzed by discrete element method, and the effect of hollow particles in cement on casing deformation was investigated by laboratory experiment method. Finally, field test was carried out to verify the improvement effect of the casing deformation based on cement slurry modification. The results show that the formation displacement can be absorbed effectively by hollow particles inside the cement transferring the excessive deformation away from casing. The particles in the uncemented state provide deformation space during formation slipping. The casing with diameter of 139.7 mm could be passed through by bridge plug with the diameter of 99 mm when the mass ratio of particle/cement reaches 1:4. According to the field test feedback, the method based on optimization of cement slurry can effectively reduce the risk of casing deformation, and the recommended range of hollow microbeads content in the cement slurry is between 15% and 25%.

关键词： Cement slurry Hollow ceramsite Casing deformation Formation slip Field test

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Intelligent responsive self-assembled micro-nanocapsules: Used to delay gel gelation time

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Petroleum Science 2024年第4期21卷 2433-2443页

作者： chuan-hong Kang Ji-Xiang Guo Dong-Tao Fei Wyclif Kiyingi Unconventional Petroleum Research Institute China University of Petroleum

In the application of polymer gels to profile control and water shutoff,the gelation time will directly determine whether the gel can "go further" in the formation,but the most of the methods for delaying gel gelation time are complicated or have low *** is an urgent need for an effective method for delaying gel gelation time with intelligent *** by the slow-release effect of drug capsules,this paper uses the self-assembly effect of gas-phase hydrophobic SiO2in aqueous solution as a capsule to prepare an intelligent responsive self-assembled *** capsule slowly releases the cross-linking agent under the stimulation of external conditions such as temperature and pH value,thus delaying gel gelation *** the pH value is 2 and the concentration of gas-phase hydrophobic SiO2particles is 10%,the gelation time of the capsule gel system at 30,60,90,and 120℃ is12.5,13.2,15.2,and 21.1 times longer than that of the gel system without containing capsule,*** with other methods,the yield stress of the gel without containing capsules was 78 Pa,and the yield stress after the addition of capsules was 322 *** intelligent responsive self-assembled micronanocapsules prepared by gas-phase hydrophobic silica nanoparticles can not only delay the gel gelation time,but also increase the gel *** slow release of cross-linking agent from capsule provides an effective method for prolongating the gelation time of polymer gels.

关键词： Profile control and water shutoff Polymer gel Delayed gelation time Intelligent response Self-assembled Micro-nanocapsules

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Intracellular redox potential-driven live-cell synthesis of CdSe quantum dots in Staphylococcus aureus

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Science China Chemistry 2024年第3期67卷 990-999页

作者： Cai-Qin Wu An-An Liu Xu Li Jia-Wei Tu Juan Kong Ling-Ling Yang Jian-hong Jia chuan Wang Bin Hu Zhi-Xiong Xie dai-Wen Pang The Institute for Advanced Studies College of Chemistry and Molecular SciencesCollege of Life SciencesHubei Key Laboratory of Cell HomeostasisWuhan UniversityWuhan 430072China Research Center for Analytical Sciences College of ChemistryState Key Laboratory of Medicinal Chemical BiologyTianjin Key Laboratory of Biosensing and Molecular RecognitionFrontiers Science Center for New Organic MatterFrontiers Science Center for Cell Responsesand Haihe Laboratory of Sustainable Chemical TransformationsNankai UniversityTianjin 300071China

Biosynthesized semiconductor quantum dots(QDs) have bright fluorescence,adjustable particle sizes,and environmental friendliness,endowing them with convenience and potential for biological *** to the unclear mechanism of the cellular environment on the live-cell synthesis of QDs,it is still difficult to regulate their optical ***,the critical role of the intracellular redox environment in regulating the fluorescence properties of biosynthesized CdSe QDs in Staphylococcus aureus(***) has been *** glutathione peroxidase(GPx) activity directly affects the intracellular H_(2)O_(2) produced in the SeO_(3)^(2-) reduction,which further manipulates the glutathione redox cycle to determine the content of low-valence *** a result,the fluorescence intensity of the synthesized CdSe QDs increases by 60% in the GPx overexpressed *** cellular redox potential that is controlled by the GSH redox cycle provides the driving force for the reduction of SeO_(3)^(2-),facilitating the synthesis of CdSe QDs in *** *** proposed mechanism of the cellular redox state provides a new perspective for regulating the synthesis of semiconductor nanomaterials in live cells.

关键词： redox H_(2)O_(2) peroxidase quantum dot Staphylococcus aureus

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Hydrogel loaded with bone marrow stromal cell-derived exosomes promotes bone regeneration by inhibiting inflammatory responses and angiogenesis

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World Journal of Stem Cells 2024年第5期16卷 499-511页

作者： Shuai Zhang chuan Lu Sheng Zheng Guang hong Division for International Collaborative and Innovative Dentistry Tohoku University Graduate School of DentistrySendai 980-8575MiyagiJapan School of Stomatology Zhejiang Chinese Medical UniversityHangzhou 310053Zhejiang ProvinceChina

BACKGROUND Bone healing is a complex process involving early inflammatory immune regu-lation,angiogenesis,osteogenic differentiation,and *** repair poses challenges for orthopedic surgeons,necessitating the search for efficient healing *** To investigate the underlying mechanism by which hydrogel-loaded exosomes derived from bone marrow mesenchymal stem cells(BMSCs)facilitate the process of fracture *** Hydrogels and loaded BMSC-derived exosome(BMSC-exo)gels were charac-terized to validate their *** vitro evaluations were conducted to assess the impact of hydrogels on various stages of the healing *** could recruit macrophages and inhibit inflammatory responses,enhance of human umbilical vein endothelial cell angiogenesis,and promote the osteogenic differen-tiation of primary cranial ***,the effect of hydrogel on fracture healing was confirmed using a mouse fracture *** The hydrogel effectively attenuated the inflammatory response during the initial repair stage and subsequently facilitated vascular migration,promoted the formation of large vessels,and enabled functional vascularization during bone *** effects were further validated in fracture *** We successfully fabricated a hydrogel loaded with BMSC-exo that modulates macrophage polarization and angiogenesis to influence bone regeneration.

关键词： Hydrogel Bone marrow mesenchymal stem cells Macrophage polarization Angiogenesis Bone regeneration

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