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Random change point model with an application to the China Household Finance Survey

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Science China Mathematics 2024年第10期67卷 2373-2386页

作者： Meng Li Lingxi Gao Guangming lv Xingwei Tong School of Statistics Beijing Normal UniversityBeijing 100875China

We consider a linear model with a change point according to the unknown random threshold of a covariate. We give the expectation-maximization(EM) estimations of the regression and change point parameters. The existence of the random change point is detected by the supremum(SUP) test of score statistics. Theoretically, we establish the convergence and asymptotic distribution of the estimation and show that the EM estimates converge in distribution to a normal distribution. In addition, the numerical performance of the proposed approach is demonstrated through simulation studies. Finally, applying our methodology to household financial decisions, we see that the average debt tolerance of Chinese households is estimated to be 1.1364 times the sum of total household income and financial assets. The effect of assets and income on consumption shows a rapid decline if the household exceeds the average debt tolerance.

关键词： random change point EM algorithm SUP test debt nancial vulnerability

Exceptional reversed yield strength asymmetry in a rare-earth free Mg alloy containing quasicrystal precipitates

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Journal of Magnesium and Alloys 2024年第2期12卷 687-699页

作者： Qiang Yang Shuhui lv Zixiang Yan Zefeng Xie Xin Qiu State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022PR China School of Materials Science and Engineering Changchun University of Science and Technology130022PR China

This work reports an exceptional reversed yield strength asymmetry at room temperature for a rare-earth free magnesium alloy containing a mass of fine dispersed quasicrystal(I-phase)*** exhibiting traditional basal texture,it owns an exceptional CYS/TYS as high as~*** back-scattered diffraction(EBSD)and transmission electron microscopy(TEM)examinations indicate pyramidal and prismatic dislocations plus tensile twinning being activated after immediate yielding in compression while basal and non-basal dislocations in tension.I-phase particles transferred the concentrated stress by self-twinning to provide the driving force for tensile twin initiating in neighboring grains,thereby significantly increasing the critical resolved shear stress of tensile twinning to possibly the level of pyramidal slip,finally leading to the dominance of pyramidal slip plus tensile twinning in texture *** results in a higher contribution on yield strength by~55 MPa in compression than in tension,which reasonably agrees with the experimental yield strength difference(~38 MPa).It can be concluded that I-phase particles influence deformation modes in tension and in compression,finally result in reversed yield strength asymmetry.

关键词： Magnesium alloy Reversed yield strength asymmetry Transmission electron microscopy(TEM) Twinning Dislocations

Hierarchical In_(2)S_(3)microflowers decorated with WO_(3)quantum dots:Sculpting S-scheme heterostructure for enhanced photocatalytic H_(2)evolution and nitrobenzene hydrogenation

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Journal of Materials Science & Technology 2024年第7期174卷 218-225页

作者： Yuan Lin lv Chen Jianhua Zhang Yunyun Gui Lijun Liu Hubei Key Laboratory of Biomass Fibers and Eco-dyeing&Finishing College of Chemistry and Chemical EngineeringWuhan Textile UniversityWuhan 430200China

Solar energy conversion and high-value chemical production are of utmost ***,the de-velopment of efficient photocatalysts with strong redox ability remains *** we report a unique 3D/0D In_(2)S_(3)/WO_(3)S-scheme heterojunction photocatalyst obtained by depositing WO_(3)quantum dots(QDs)onto hierarchical In_(2)S_(3)*** In_(2)S_(3)/WO_(3)composite exhibits outstanding visible light absorption,with a maximum optical response of up to 600 *** electronic interaction and charge separation at interfaces are explored by in situ X-ray photoelectron spectroscopy(XPS)and density func-tional theory(DFT)*** difference in work function causes In_(2)S_(3)to donate electrons to WO_(3)upon combination,leading to the formation of an internal electric field(IEF)at the *** to the IEF and bent energy bands,the transfer and separation of photogenerated charge carriers follow an S-scheme pathway within In_(2)S_(3)/WO_(3).Owing to the strong redox ability,spatial charge separation and lower H 2-generation barrier of S active sites,the optimized In_(2)S_(3)/WO_(3)heterojunctions show enhanced photocatalytic hydrogen evolution of 0.39 mmol h^(-1)g^(-1),6.7 times that of pristine In_(2)S_(3).In addition,the In_(2)S_(3)/WO_(3)S-scheme heterojunctions afford a remarkable activity for photocatalytic nitrobenzene hydro-genation with nearly 98%conversion and 99%selectivity of aniline within 1 *** work might present new insights into developing efficient S-scheme heterojunctions for various photocatalytic applications.

关键词： S-scheme heterojunctions In_(2)S_(3)microflowers WO_(3)quantum dots H_(2)production Electron transfer

Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

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Journal of Magnesium and Alloys 2024年第4期12卷 1449-1460页

作者： Guishang Pei Cheng Pan Dapeng Zhong Junyi Xiang Xuewei lv College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China Pangang Group Research Institute Co. Ltd.Panzhihua 617000China

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted considerable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air *** solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kJ/*** endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kJ/mol,which is related to the incongruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high *** cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is controlled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating ***,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(J mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

关键词： MgV_(2)O_(6) Crystal structure Phase transitions Thermodynamic functions

Energy consumption optimization for edge computing-supported cellular networks based on optimal transport theory

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Science China(Information Sciences) 2024年第2期67卷 201-218页

作者： Xiangyu lv Xiaohu GE Yi ZHOng Qiang LI Yong XIAO School of Electronic Information and Communications Huazhong University of Science and Technology

With advancements in mobile communication technologies, there have been multiple user device(UD) connections to cellular networks. Because of changes in the spatial distribution of UDs and application requirements, the traditional offloading mechanism based on the nearest distance will result in heavy loads for some base stations(BSs). Because there is a high-order relationship between the energy consumption of the BS processing tasks and the number of computing tasks, the traditional offloading mechanism will result in high energy consumption, and UD’s offloading decision must be dynamically adjusted. The offloading decision of UDs is optimized based on detailed information about various parameters associated with a network from the standpoint of distribution. This information includes details regarding the spatial distribution of UDs,application requirements, and the offloading period of computing tasks. Based on optimal transport theory,an energy consumption optimization algorithm is suggested to lower the total amount of energy consumed by the offloading process of UDs’ computing tasks by reasonably planning the offloading BSs of the UDs in the networks. The simulation results show that the proposed offloading mechanism based on energy consumption optimization reduces the total energy consumption of the offloading process by 28.09% when compared to the traditional offloading mechanism, and the traffic managed by each BS is balanced.

关键词： optimal transport theory edge computing energy consumption reduction dynamic voltage frequency scaling

Point Cloud Classification Using Content-Based Transformer via Clustering in Feature Space

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 231-239页

作者： Yahui Liu Bin Tian Yisheng lv Lingxi Li Fei-Yue Wang the State Key Laboratory for Management and Control of Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190 the School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100190 IEEE the Transportation and Autonomous Systems Institute(TASI)and the Department of Electrical and Computer Engineering Purdue School of Engineering and TechnologyIndiana University-Purdue University Indianapolis(IUPUI)Indianapolis 46202 USA

Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to establish relationships between distant but relevant points. To overcome the limitation of local spatial attention, we propose a point content-based Transformer architecture, called PointConT for short. It exploits the locality of points in the feature space(content-based), which clusters the sampled points with similar features into the same class and computes the self-attention within each class, thus enabling an effective trade-off between capturing long-range dependencies and computational complexity. We further introduce an inception feature aggregator for point cloud classification, which uses parallel structures to aggregate high-frequency and low-frequency information in each branch separately. Extensive experiments show that our PointConT model achieves a remarkable performance on point cloud shape classification. Especially, our method exhibits 90.3% Top-1 accuracy on the hardest setting of ScanObjectN N. Source code of this paper is available at https://***/yahuiliu99/PointC onT.

关键词： Content-based Transformer deep learning feature aggregator local attention point cloud classification

Rupture of a giant jejunal mesenteric cystic lymphangioma misdiagnosed as ovarian torsion: A case report

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World Journal of Clinical Cases 2024年第4期12卷 847-852页

作者： Jing Xu Tie-Feng lv Department of Hepatopathy Hangzhou Xixi HospitalHangzhou 310023Zhejiang ProvinceChina

BACKGROUND Cystic lymphangioma is a rare benign tumor that affects the lymphatic *** lymphangiomas in the small bowel are extremely *** SUMMARY We present a 21-year-old female patient who complained of abdominal *** diagnosis of ovarian torsion was suspected after abdominopelvic unenhanced computed tomography and ultrasound revealed a large cyst in contact with the bladder,ovary,and *** patient underwent emergency laparotomy per-formed by gynecologists,but it was discovered that the cystic tumor originated from the *** surgeons were then called in to perform a *** examination confirmed the diagnosis of cystic lymphangioma of the *** patient had an uneventful postoperative *** Mesenteric lymphangiomas can cause abdominal pain,and imaging techniques can help determine their characteristics,location,and *** surgical excision and pathological examination are considered the standard treatment and diagnostic method.

关键词： Rupture Jejunum Mesenteric cystic lymphangioma Ovarian torsion Surgical excision Pathological examination Case report

Multi-objective optimal control of tungiasis diseases with terminal demands

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International Journal of Biomathematics 2024年第3期17卷 123-151页

作者： Wei lv Si-Ting Zhang Lei Wang Department of Mathematics Shanghai University Shanghai200444P.R.China Key Laboratory for Computational Mathematics and Data Intelligence of Liaoning Province Dalian University of Technology Dalian 116024P.R.China Department of Mathematics School of Science Shihezi UniversityShihezi 832003P.R.China

In this paper,we aim to minimize the epidemic size of tungiasis disease and economic costs simultaneously,with terminal demands for infected humans.A human-jigger parasite control system with four control schemes for humans and jiggers is *** propose a multi-objective optimal control problem with terminal constraints,in which the accumulated number of infected humans and control costs are *** applying the modified normal boundary intersection algorithm and the interior point scheme,numerical simulations for different combinations of control schemes are carried out,and actual data in Madagascar are *** combination schemes are indicated from the perspectives of disease eradication,cost saving and time *** these effective combinations are properly performed,the disease can be *** only minimizing the epidemic size,the combination of the optimal treatments and adulticiding efforts is the best choice in the rainy season;the combination of the optimal personal protections and treatments is the preferential option in the dry *** only minimizing the economical cost,the combination of the optimal adulticide and larvicide is the better selection in the rainy season;the combination of the optimal personal protections,treatments and adulticiding efforts is the prior choose in the dry ***,there is a trade-off between the two objectives for all the effective combinations,decision-makers may choose an appropriate one to control the disease.

关键词： Multi-objective optimal control terminal demand control combination tun-giasis disease

Early prediction and prevention of infected pancreatic necrosis

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World Journal of Gastroenterology 2024年第9期30卷 1005-1010页

作者： Cheng lv Zi-Xiong Zhang Lu Ke Department of Critical Care Medicine Jinling HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210000Jiangsu ProvinceChina Research Institute of Critical Care Medicine and Emergency Rescue Nanjing UniversityNanjing 210000Jiangsu ProvinceChina

Approximately 20%-30%of patients with acute necrotizing pancreatitis develop infected pancreatic necrosis(IPN),a highly morbid and potentially lethal *** identification of patients at high risk of IPN may facilitate appropriate preventive measures to improve clinical *** the past two decades,several markers and predictive tools have been proposed and evaluated for this *** biomarkers like C-reactive protein,procalcitonin,lymphocyte count,interleukin-6,and interleukin-8,and newly developed biomarkers like angiopoietin-2 all showed significant association with *** the other hand,scoring systems like the Acute Physiology and Chronic Health Evaluation II and Pancreatitis Activity Scoring System have also been tested,and the results showed that they may provide better *** early prevention of IPN,several new therapies were tested,including early enteral nutrition,anti-biotics,probiotics,immune enhancement,etc.,but the results *** together,several evidence-supported predictive markers and scoring systems are readily available for predicting ***,effective treatments to reduce the incidence of IPN are still lacking apart from early enteral *** this editorial,we summarize evidence concerning early prediction and prevention of IPN,providing insights into future practice and study design.A more homo-geneous patient population with reliable risk-stratification tools may help find effective treatments to reduce the risk of IPN,thereby achieving individualized treatment.

关键词： Acute pancreatitis Infected pancreatic necrosis Biomarker Scoring system Nutrition therapy Selective digestive decontamination Probiotics Antibiotics Immune enhancement therapy