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Feature selection for probabilistic load forecasting via sparse penalized quantile regression

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Journal of Modern Power Systems and Clean Energy 2019年第5期7卷 1200-1209页

作者： Yi wang Dahua GAN Ning zhang Le XIE Chongqing kang Department of Electrical Engineering Tsinghua UniversityBeijingChina Department of Electrical and Computer Engineering Texas A&M UniversityUvaldeTXUSA

Probabilistic load forecasting(PLF)is able to present the uncertainty information of the future *** is the basis of stochastic power system planning and *** works on PLF mainly focus on how to develop and combine forecasting models,while the feature selection issue has not been thoroughly investigated for *** paper fills the gap by proposing a feature selection method for PLF via sparse L1-norm penalized quantile *** can be viewed as an extension from point forecasting-based feature selection to probabilistic forecasting-based feature *** both the number of training samples and the number of features to be selected are very large,the feature selection process is casted as a large-scale convex optimization *** alternating direction method of multipliers is applied to solve the problem in an efficient *** conduct case studies on the open datasets of ten *** results show that the proposed feature selection method can improve the performance of the probabilistic forecasting and outperforms traditional least absolute shrinkage and selection operator method.

关键词： Probabilistic load forecasting Feature selection Alternating direction method of multipliers(ADMM) Quantile regression L1-norm penalty

Topology characteristics of three-dimensional grains in polycrystalline materials

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Science China(Technological Sciences) 2019年第2期62卷 263-268页

作者： wang Hao XUE WeiHua kang RenMu zhang YiFan LIU GuoQuan School of Materials Science and Engineering University of Science and Technology Beijing School of Materials Science and Engineering Liaoning Technical University Deyang Products Quality Supervision and Inspection Institute Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing

The quantitative microstructural analysis in recrystallized pure iron is carried out by serial sectioning experiment coupled with three-dimensional(3-D) grain reconstruction technique. The full 3-D morphology of 16254 pure iron grains, which is the largest experimental 3-D grain dataset to date, is obtained. It is shown that the peak and the mean of the grain face number distribution were 10 and 13.5, respectively. For individual grains, the average trends that the highest and lowest face classes exhibited the highest affinity for mutual contact but the lowest affinity for contact with themselves are experimentally confirmed by 3-D pure iron grains. The pure iron grains are observed to have much more three-edged faces than Monte Carlo grains, resulting in relatively higher average dispersions of the grain edge distribution.

关键词： 3-D characterization serial sectioning Monte Carlo grain growth topology

Saline-alkali soil reclamation and utilization in China:progress and prospects

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Frontiers of Agricultural Science and Engineering 2024年第2期11卷 216-228页

作者： Guangzhou wang Gang NI Gu FENG Haley MBURRILL Jianfang LI junling zhang Fusuo zhang State Key Laboratory of Nutrient Use and Management(SKLNUM) College of Resources and Environmental SciencesNational Academy of Agriculture Green DevelopmentChina Agricultural UniversityBeijing 100193China The Institute of Ecology and Evolution University of OregonEugeneOR97403USA

Soil salinity is a global threat to the productivity of arable land. With the impact of population growth and development of social economy in China, the area of arable land has been shrinking in recent decades and is approaching a critical threshold of 120 Mha, the minimum area for maintaining the national food security. Saline-alkaline land, as important backup reserve, has been receiving increased attention as an opportunity to expand land resources. This review first summarizes the general principles and technologies of saline soil reclamation to support plant growth, including leaching salts or blocking the rise of salts, and soil fertility enhancement to improve the buffering *** the progress in this area in China is described including the customization of technologies and practices used in different saline-alkali regions. Following the soil management strategies, the concept of selecting crops for saline soil is proposed. This encompasses halophyte planting, salt-tolerant crop breeding and the application of saline-adapted functional microorganisms to improve the adaptation of crops. Finally, the current problems and challenges are evaluate, and future research directions and prospects proposed for managing this major soil constraint.

关键词： Food security land reserve reclamation saline-alkali soil utilization

Precipitation behaviors and mechanical properties of a solution-treated Mg-Gd-Nd-Zn-Zr alloy during equal-channel angular pressing process

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Journal of Magnesium and Alloys 2022年第1期10卷 257-266页

作者： Zhenzhen Gui Fen wang Junyi zhang Dexin Chen Zhixin kang School of Mechanical and Electrical Engineering Guangzhou University230 Wai Huan Xi RoadGuangzhou Higher Education Mega CenterGuangzhou 510006China Guangdong Key Laboratory for Advanced Metallic Materials Processing School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou 510640China Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan University601 Hmmgpu Avenue WestGuangzhou 510632China

A magnesium alloy processed by equal-channel angular pressing (ECAP) exhibited excellent microstructure refinement and improved strength and *** comprehensive mechanical properties of magnesium alloys have supported the expansion of their applications in the automotive,aerospace,and biomedical ***,pre-treatment of a solution-treated Mg-2.9Gd-1.5Nd-0.3Zn-0.3Zr alloy was conducted to investigate the precipitate behavior and microstructure evolution during the ECAP process.β;phase grains quickly precipitated from the solution-treated alloy,which accelerated grain refinement and enhanced the ductility after the ECAP process,as compared to the as-cast alloy reported in our previous ***,spherical precipitates (~200 nm) and fine phases (~100 nm) precipitated along the stripe-like Zn;Zr;phase,which formed a kabap-like structure dispersing homogeneously in the solution-treated alloy during the ECAP *** to grain refinement,dislocations,sphericalβ;precipitates,and texture evolution,the solution-treated alloy after eight passes of ECAP exhibited good comprehensive mechanical properties,with the ultimate tensile strength,yield strength,and elongation values reaching210.9 MPa,263.9 MPa,and 27.9%,respectively.

关键词： Mg-Gd-Nd-Zn-Zr alloy Precipitations Solid solution ECAP Mechanical properties

Analysis of Thermoelastohydrodynamic Performance of Journal Misaligned Engine Main Bearings

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Chinese Journal of Mechanical Engineering 2015年第3期28卷 511-520页

作者： BI Fengrong SHAO kang LIU Changwen wang Xia zhang Jian State Key Laboratory of Engines Tianjin University

To understand the engine main bearings＇ working condition is important in order to improve the performance of engine. However, thermal effects and thermal effect deformations of engine main bearings are rarely considered simultaneously in most studies. A typical finite element model is selected and the effect of thermoelastohydrodynamic（TEHD） reaction on engine main bearings is investigated. The calculated method of main bearing＇s thermal hydrodynamic reaction and journal misalignment effect is finite difference method, and its deformation reaction is calculated by using finite element method. The oil film pressure is solved numerically with Reynolds boundary conditions when various bearing characteristics are calculated. The whole model considers a temperature-pressure-viscosity relationship for the lubricant, surface roughness effect, and also an angular misalignment between the journal and the bearing. Numerical simulations of operation of a typical I6 diesel engine main bearing is conducted and importance of several contributing factors in mixed lubrication is discussed. The performance characteristics of journal misaligned main bearings under elastohydrodynamic（EHD） and TEHD loads of an I6 diesel engine are received, and then the journal center orbit movement, minimum oil film thickness and maximum oil film pressure of main bearings are estimated over a wide range of engine operation. The model is verified through the comparison with other present models. The TEHD performance of engine main bearings with various effects under the influences of journal misalignment is revealed, this is helpful to understand EHD and TEHD effect of misaligned engine main bearings.

关键词： main bearings journal misaligned oil film pressure Reynolds equation finite difference methods thermoelastohydrodynamic(TEHD)

Single-cell transcriptional profile of ACE2 in healthy and failing human hearts

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Science China(Life Sciences) 2021年第4期64卷 652-655页

作者： Yitian Zhou Yongfa Huang Xiaomin Song Xiaoxiao Guo junling Pang Jing wang Shuyang zhang Chen wang State Key Laboratory of Medical Molecular Biology.Institute of Basic Medical Sciences Chinese Academy of Medical SciencesDeparment of Pathophysiology.Peking Union Medical CollegeBejing 100730China Deparment of Cardiology Peking Union Medlical College HospialPeking Union Medical College and Chinese Academy of Medical SciencesBejing 100730China Slate Key Laboratory of Medical Molecular Biology Institute of Basic Medical SciencesChinese Academy of Medical SciencesDepartment of PlhysiologPeking Union Medical CollegeBeijing 100730China

Dear Editor,The coronavirus disease 2019(COVID-19)pandemic,which is caused by SARS-Co V-2,has gained serious attention from medical practitioners around the world in the past few *** 20%of critically ill COVID-19 patients were reported to have suffered myocardial *** specific mechanism of this pathology requires further investigation(Yang et al.,2020).

关键词： ACE2 al. pathology

Highly ordered Nb_(2)O_(5)nanochannel film with rich oxygen vacancies for electrocatalytic N2 reduction:Inactivation and regeneration of electrode

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Chinese Chemical Letters 2021年第9期32卷 2833-2836页

作者： Jialu wang Shenghong kang Xiaoguang Zhu Guozhong wang Haimin zhang Key Laboratory of Materials Physics Centre for Environmental and Energy NanomaterialsAnhui Key Laboratory of Nanomaterials and NanotechnologyInstitute of Solid State PhysicsChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China

We report the fabrication of highly ordered Nb_(2)O_(5)nanochannel film(Nb_(2)O_(5)-NCF)onto niobium foil by an anodization *** thermal treatment,the obtained Nb_(2)O_(5)-NCF with rich oxygen vacancies exhibits electrochemical N_(2)reduction reaction(NRR)activity with an NH3 yield rate of 2.52×10^(-10)mol cm^(-2)s^(-1)and a faradaic efficiency of 9.81%at-0.4 V(***)in 0.1 mol/L Na2SO4 electrolyte(pH 3.2).During electrocatalytic NRR,the Nb_(2)O_(5)-NCF takes place electrochromism(EC),along with a crystalline phase transformation from pseudo hexagonal phase to hexagonal phase owing to H+*** results in the reduced NRR activity due to the decrease of oxygen vacancies of hexagonal phase Nb_(2)O_(5),which can be readily regenerated by low-temperature thermal treatment or applying an anodic potential,showing superior recycling reproducibility.

关键词： Niobium oxide(Nb_(2)O_(5)) Nitrogen(N_(2))reduction reaction(NRR) Electrochromism Oxygen vacancies Phase transformation

Improving fatigue properties of normal direction ultrasonic vibration assisted face grinding Inconel 718 by regulating machined surface integrity

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International Journal of Extreme Manufacturing 2024年第3期6卷 458-475页

作者： Nianwei Xu Renke kang Bi zhang Yuan zhang Chenxu wang Yan Bao Zhigang Dong State Key Laboratory of High-Performance Precision Manufacturing Dalian University of TechnologyDalian 116024People’s Republic of China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055People’s Republic of China

Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),and microhardness)after machining ***-direction ultrasonic vibration-assisted face grinding(ND-UVAFG)has advantages in improving the machinability of Inconel 718,but there is a competitive relationship between higher compressiveσ_(res)and higher surface roughness R_(a)in affecting fatigue *** lack of a quantitative relationship between multiple SI indexes and fatigue strength makes theindeterminacy of a regulatory strategy for improving fatigue *** this work,a model of fatigue strength(σ_f)_(sur)considering multiple SI indexes was ***,high-cycle fatigue tests were carried out on Inconel 718 samples with different SI characteristics,and the influence of ND-UVAFG process parameters on SI was *** on SI indexes data,the(σ_f)_(sur)distribution in the grinding surface layer for ND-UVAFG Inconel 718 samples was determined using the developed model,and then the fatigue crack initiation(FCI)sites were *** predicted FCI sites corresponded well with the experimental results,therebyverifying this model.A strategy for improving the fatigue life was proposed in this work,which was to transfer the fatigue source from the machined surface to the bulk material by controlling the SI ***,a critical condition of SI indexes that FCI sites appeared on the surface or in bulk material was given by fitting the predicted *** to the critical condition,an SI field where FCI sites appeared in the bulk material could be *** this field,thefatigue life of Inconel 718 samples could be improved by approximately 140%.

关键词： surface integrity fatigue strength Inconel 718 ultrasonic assisted grinding

Helicobacter pylori antibody responses in association with eradication outcome and recurrence： a population-based intervention trial with 7.3-year follow-up in China

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Chinese Journal of Cancer Research 2017年第2期29卷 127-136页

作者： Tianyi wang Yang zhang Huijuan Su Zhexuan Li Lian zhang junling Ma Weidong Liu Tong Zhou Weicheng You Kaifeng Pan Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing) Department of Cancer Epidemiology Peking University Cancer Hospital & Institute Beijing 100142 China Linqu Public Health Bureau Linqu 262600 China

Objective： To identify serum biomarkers that may predict the short or long term outcomes of anti-Helicobacter gylori （H. pylori） treatment, a follow-up study was performed based on an intervention trial in Linqu County, China. Methods： A total of 529 subjects were selected randomly from 1,803 participants to evaluate total anti-H, pylori immunoglobulin G （IgG） and 10 specific antibody levels before and after treatment at 1-, 2- and 7.3-year. The outcomes of anti-H, pylori treatment were also parallelly assessed by 13C-urea breath test at 45-d after treatment and 7.3-year at the end of follow-up. Results： We found the medians of anti-H, pylori IgG titers were consistently below cut-off value through 7.3 years in eradicated group, however, the medians declined in recurrence group to 1.2 at 1-year after treatment and slightly increased to 2.0 at 7.3-year. While the medians were significantly higher （〉3.0 at 2- and 7.3-year） among subjects who failed the eradication or received placebo. For specific antibody responses, baseline seropositivities of FliD and HpaA were reversely associated with eradication failure [for FIiD, odds ratio （OR）=0.44, 95% confidence interval （95% CI）： 0.27-0.73; for HpaA, OR=0.32, 95% Ch 0.I7-0.60]. The subjects with multiple positive specific antibodies at baseline were more likely to be successfully eradicated in a linear fashion （Ptrend=0.006）. Conclusions： Our study suggested that total anti-H, pylori IgG level may serve as a potential monitor of long- term impact on anti-H, pylori treatment, and priority for H. pylori treatment may be endowed to the subjects with multiple seropositive antibodies at baseline, especially for FliD and HapA.

关键词： Helicobacterpylori biomarker serology treatment outcome recurrence