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The Consistency of LSE Estimators in Partial Linear Regression Models under Mixing Random Errors

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1244-1272页

作者： Yun Bao YAO Yu tan LÜ Chao LU Wei WAnG Xue Jun WAnG School of Mathematical Sciences Anhui UniversityHefei 230601P.R.China School of Big Data and Artificial Intelligence Chizhou UniversityChizhou 247000P.R.China School of Big Data and Statistics Anhui UniversityHefei 230601P.R.China

In this paper,we consider the partial linear regression model y_(i)=x_(i)β^(*)+g(ti)+ε_(i),i=1,2,...,n,where(x_(i),ti)are known fixed design points,g(·)is an unknown function,andβ^(*)is an unknown parameter to be estimated,random errorsε_(i)are(α,β)-mix_(i)ng random *** p-th(p>1)mean consistency,strong consistency and complete consistency for least squares estimators ofβ^(*)and g(·)are investigated under some mild *** addition,a numerical simulation is carried out to study the finite sample performance of the theoretical ***,a real data analysis is provided to further verify the effect of the model.

关键词： (α,β)-mixing random variables partial linear regression model least squares estimator consistency

A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 146-156页

作者： Thong Duc Hong Minh Quang Pham Son Cong Tran Lam Quang Tran Truong Thanh nguyen Faculty of Transportation Engineering Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam Vietnam national University Ho Chi Minh City(VnU-HCM) Ho Chi Minh City 700000Vietnam Industrial Maintenance Training Center Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been *** mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding *** simulation findings are compared to the analytical calculation results in the steady state,and both methods show good *** the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model ***,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting *** established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system *** is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

关键词： Dump truck Lifting mechanism Hydraulic MATLAB Simscape Kinetic dynamic analysis

Assembly of a core–shell MOF with stability into polyacrylamide hydrogel for boosting extraction of uranium from seawater

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nano Research 2024年第4期17卷 3398-3406页

作者： Yucheng Song Huanhuan tan Shiliang Qin Zhong Liu Chuntai Liu Changyu Shen Peipei Yang Songwei Li national Engineering Research Center for Advanced Polymer Processing Technology Key Laboratory of Materials Processing and Mold(Ministry of Education)Zhengzhou UniversityZhengzhou 450002China Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt LakesQinghai Institute of Salt LakesChinese Academy of SciencesXining 810008China

Efficient and selective extraction of uranium(U(VI))from seawater is essential for sustainable nuclear power *** study reports a novel adsorbent zeolitic imidazolate framework(ZIF)-67@SiO_(2)-A/polyacrylamide(PAM)which was synthesized by grafting the core–shell metal–organic frameworks(MOFs)-based nanostructures coated with the 3-aminopropyl triethoxysilane(APTES)functionalized SiO_(2)(SiO_(2)-A)onto PAM *** SiO_(2) shell was grown on the surface of MOF,which improved the acid-base resistance of *** introduction of ZIF-67@SiO_(2)-A enhances the specific surface area and adsorption efficiency of the *** ZIF-67@SiO_(2)-A/PAM shows remarkable adsorption capacity,fast adsorption kinetics,and good reusability for *** has excellent adsorption property(6.33 mg·g^(-1),30 d)in natural *** X-ray photoelectron spectroscopy(XPS),Fourier transform infrared(FTIR),energy dispersive spectroscopy(EDS)mappings,and density functional theory reveal that the coordination by n and O in ZIF-67@SiO_(2)-A/PAM with uranium is the main mechanism of uranium ***,ZIF-67@SiO_(2)-A/PAM has great potential to capture uranium from natural seawater.

关键词： hydrogel metal–organic frameworks core–shelled nanostructures uranium extraction from seawater

Three-dimensionally ordered macroporous(3DOM) structure promoted the activity and H_(2)O poisoning resistance of Ce Mn/3DOM-TiO_(2) catalyst in nH_(3)-SCR

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Journal of Rare Earths 2024年第3期42卷 523-533,I0004页

作者： Yaqin Hu Shipeng Ding Chenchen tan Peng Wu Guobo Li Sheng Wang Hongqiang Yang Yaping Zhang Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing210096China State Power Environmental Protection Research Institute Nanjing210031China

nH_(3)-SCR is an effective mean of nOxremoval in the non-electric industry, however, the high activation temperature and poor H_(2)O resistance of SCR catalysts posed a barrier to its application. In this work, a series of three-dimensionally ordered macroporous(3DOM) catalysts were synthesized via a colloidal crystal template(CCT) method, and various characterizations were carried out to explore the physicochemical property of catalysts. The experiment results reveal that Ce_(0.2)Mn_(0.2)/3DOM-TiO_(2) catalyst presents the excellent low-temperature catalytic activity of nearly 100% at 100℃. Furthermore, the enhanced H_(2)O resistance is achieved, certified by the unaffected nO remove at 150℃ in the participation of 15 vol% H_(2)O. The characterizations results exhibit that the improved dispersion of the active component and enhanced redox ability are conducive to the low-temperature catalytic activity. n_(2) adsorption and desorption experiments indicate that catalyst with 3DOM support possesses a larger pore diameter and specific surface area, which may weaken the condensation of H_(2)O in the microporosity of catalysts and improved the H_(2)O resistance of the catalyst. In situ DRIFTS results manifest that Ce_(0.2)Mn_(0.2)/3DOM-TiO_(2) catalyst could not only absorb more nH_(3) and generate more surface-active sites, but inhibit the competitive adsorption between H_(2)O and SCR reactants.

关键词： 3DOM material nH_(3)-SCR H_(2)O resistance Low-temperature Cerium Rare earths

Damage evolution of rock-encased-backfill structure under stepwise cyclic triaxial loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 597-615页

作者： Xin Yu Yuye tan Weidong Song John Kemeny Shengwen Qi Bowen Zheng Songfeng Guo Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100089China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing100089China University of Chinese Academy of Sciences Beijing100049China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of China) University of Science and Technology BeijingBeijing100083China Department of Mining and Geological Engineering University of ArizonaTucsonAZ86721USA

Rock-encased-backfill(RB)structures are common in underground mining,for example in the cut-andfill and stoping *** understand the effects of cyclic excavation and blasting activities on the damage of these RB structures,a series of triaxial stepwise-increasing-amplitude cyclic loading experiments was conducted with cylindrical RB specimens(rock on outside,backfill on inside)with different volume fractions of rock(VF=0.48,0.61,0.73,and 0.84),confining pressures(0,6,9,and 12 MPa),and cyclic loading rates(200,300,400,and 500 n/s).The damage evolution and meso-crack formation during the cyclic tests were analyzed with results from stress-strain hysteresis loops,acoustic emission events,and post-failure X-ray 3D fracture *** results showed significant differences between cyclic and monotonic loadings of RB specimens,particularly with regard to the generation of shear microcracks,the development of stress memory and strain hardening,and the contact forces and associated friction that develops along the rock-backfill *** important finding is that as a function of the number of cycles,the elastic strain increases linearly and the dissipated energy increases ***,compared with monotonic loading,the cyclic strain hardening characteristics are more sensitive to rising confining pressures during the initial compaction *** finding is that compared with monotonic loading,more shear microcracks are generated during every reloading stage,but these microcracks tend to be dispersed and lessen the likelihood of large shear fracture *** transition from elastic to plastic behavior varies depending on the parameters of each test(confinement,volume fraction,and cyclic rate),and an interesting finding was that the transformation to plastic behavior is significantly lower under the conditions of 0.73 rock volume fraction,400 n/s cyclic loading rate,and 9 MPa *** the findings have important practical implications on t

关键词： Rock and backfill Triaxial cyclic loading Volume fraction Damage evolution 3D visualization

越南学生“常常”“往往”习得偏误及教学对策研究

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越南学生“常常”“往往”习得偏误及教学对策研究

作者： nguyen THI LUU LY （阮氏琉璃）河北大学

学位级别：硕士

Thornthwaite moisture index and depth of suction change under current and future climate‒An Australian study

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1761-1775页

作者： Md Rajibul Karim Bikash Devkota Md Mizanur Rahman Hoang Bao Khoi nguyen UniSA STEM University of South AustraliaMawson Lakes CampusMawson LakesSouth Australia5095Australia

Climate change is one of the major global challenges and it can have a significant influence on the behaviour and resilience of geotechnical *** changes in moisture content in soil lead to effective stress changes and can be accompanied by significant volume changes in reactive/expansive *** volume change leads to ground movement and can exert additional stresses on structures founded on or within a shallow depth of such *** change is likely to amplify the ground movement potential and the associated problems are likely to *** effect of atmospheric boundary interaction on soil behaviour has often been correlated to Thornthwaite moisture index(TMI).In this study,the long-term weather data and anticipated future projections for various emission scenarios were used to generate a series of TMI maps for *** changes in TMI were then correlated to the depth of suction change(H s),an important input in ground movement *** all climate scenarios considered,reductions in TMI and increases in H s values were observed.A hypothetical design scenario of a footing on expansive soil under current and future climate is *** is observed that a design that might be considered adequate under the current climate scenario,may fail under future scenarios and accommodations should be made in the design for such events.

关键词： Climate change Future prediction Thornthwaite moisture index(TMI) Characteristic surface movement Infrastructure resilience

KLF4 Inhibits the Activation of Human Hepatic Stellate Cell In Vitro

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Current Medical Science 2024年第3期44卷 512-518页

作者： Xing-yu YAnG Zhe CHEn Jun tan Yin-kai XUE Hai ZHEnG Department of Emergency Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China Department of Thoracic Surgery The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an710061China Department of Thoracic Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China

Objective Hepatic stellate cells(HSCs)play a crucial role in liver ***-stage liver fibrosis is reversible and intimately associated with the state of ***-like factor 4(KLF4)plays a pivotal role in a wide array of physiological and pathological *** study aimed to investigate the effect of KLF4 on the proliferation,apoptosis and phenotype of quiescent HSCs Methods We designed a KLF4 lentiviral vector and a KLF4 siRnA lentiviral vector,to upregulate and silence KLF4 expression in human HSC LX-2 cells via *** proliferation was assessed using the CCK-8 *** cytometry was used to detect the cell cycle distribution and apoptosis *** blotting was used to determine the levels of some quiescence and activation markers of HSCs Results Overexpression of KLF4 significantly increased the levels of E-cadherin and ZO-1,which are quiescent HSC markers,while significantly decreased the levels of n-cadherin and a-SMA,known activated HSC *** contrast,cell proliferation and apoptosis rates were elevated in LX-2 cells in which KLF4 expression was silenced Conclusion KLF4 inhibits the proliferation and activation of human LX-2 *** might be a key regulatory protein in the maintenance of HSC quiescence and may serve as a target for the inhibition of hepatic fibrosis.

关键词： Kruppel-like factor 4 hepatic stellate cells LX-2 cells liver fibrosis

Discrepant responses of soil organic carbon dynamics to nitrogen addition in different layers: a case study in an agroecosystem

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Frontiers of Agricultural Science and Engineering 2024年第2期11卷 314-325页

作者： Hualing HU Liang ZHAO Wenbing tan Guoan WAnG Beidou XI Technical Centre for Soil Agriculture and Rural Ecology and EnvironmentMinistry of Ecology and EnvironmentBeijing 100012China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193China

Empirical research indicates that heightened soil nitrogen availability can potentially diminish microbial decomposition of soil organic carbon(SOC).nevertheless, the relationship between SOC turnover response to n addition and soil depth remains unclear. In this study, soils under varying n fertilizer application rates were sampled up to 100 cm deep to examine the contribution of both new and old carbon to SOC across different soil depths,using a coupled carbon and nitrogen isotopic approach. The SOC turnover time for the plot receiving low n addition(250 kg·ha^(-1)·yr^(-1) n) was about 20-40 years. Conversely, the plot receiving high n(450 kg·ha^(-1)·yr^(-1) n) had a longer SOC turnover time than the low n plot, reaching about 100 years in the upper 10-20 cm layer. The rise in SOC over the entire profile with low n addition primarily resulted from an increase in the upper soil(0-40 cm)whereas with high n addition, the increase was mainly from greater SOC in the deeper soil(40-100 cm). Throughout the entire soil layer, the proportion of new organic carbon derived from maize C_4 plant sources was higher in plots treated with a low n rate than those treated with a high n rate. This implies that, in contrast to low n addition agricultural practices, high n addition predominantly enhances the soil potential for fixing SOC by transporting organic matter from surface soils to deeper layers characterized by more stable properties. This research offers a unique insight into the dynamics of deep carbon under increased n deposition, thereby aiding in the formulation of policies for soil carbon management.

关键词： ^(13)C natural abundance nitrogen addition soil depth organic carbon turnover