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TIME-EXTRAPOLATION ALGORITHM （TEA） FOR LINEAR PARABOLIC PROBLEMS

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Journal of Computational Mathematics 2014年第2期32卷 183-194页

作者： Hongling hu Chuanmiao Chen Kejia Pan College of Mathematics and Computer Science Key Laboratory of High Performance Computing and Stochastic Information Processing (HPCSIP) (Ministry of Education of China) Hunan Normal University Changsha 410081 China School of Mathematics and Statistics Central South University Changsha 410083 China

The fast solutions of Crank-Nicolson scheme on quasi-uniform mesh for parabolic prob- lems are discussed. First, to decrease regularity requirements of solutions, some new error estimates are proved. Second, we analyze the two characteristics of parabolic discrete scheme, and find that the efficiency of Multigrid Method （MG） is greatly reduced. Nu- merical experiments compare the efficiency of Direct Conjugate Gradient Method （DCG） and Extrapolation Cascadic Multigrid Method （EXCMG）. Last, we propose a Time- Extrapolation Algorithm （TEA）, which takes a linear combination of previous several level solutions as good initial values to accelerate the rate of convergence. Some typical extrapolation formulas are compared numerically. And we find that under certain accuracy requirement, the CG iteration count for the 3-order and 7-level extrapolation formula is about 1/3 of that of DCG＇s. Since the TEA algorithm is independent of the space dimension, it is still valid for quasi-uniform meshes. As only the finest grid is needed, the proposed method is regarded very effective for nonlinear parabolic problems.

关键词： Parabolic problem Crank-Nicolson scheme Error estimates Time-extrapolationalgorithm CG-iteration.

Efficient reduction and adsorption of Cr(Ⅵ)using FeCl_(3)-modified biochar:Synergistic roles of persistent free radicals and Fe(Ⅱ)

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Journal of Environmental Sciences 2024年第3期137卷 626-638页

作者： Shujie hu Chengshuai Liu hongling Bu Manjia Chen Ying-heng Fei National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of ScienceGuiyang 550081China School of Environment Science and Engineering Guangzhou UniversityGuangzhou 510006China College of Resources and Environment Chongqing SchoolUniversity of Chinese Academy of SciencesChongqing 400714China School of Environmental Science and Engineering Guangdong University of TechnologyGuangzhou 510006China

Transition metal iron and persistent free radicals(PFRs)both affect the redox properties of biochar,but the electron transfer relationship between them and the coupling reduction mechanism of Cr(Ⅵ)requires further investigation.To untangle the interplay between iron and PFRs in biochar and the infuences on redox properties,FeCl_(3)-modified rice husk biochar(FBCs)was prepared and its reduction mechanism for Cr(Ⅵ)without light was evaluated.The FBCs had higher surface positive charges,oxygen-containing functional groups,and PFRs compared with pristine rice husk biochar(BC).Phenoxyl PFRs with high electrondonating capability formed in biochar.The pronounced electron paramagnetic resonance signals showed that the PFRs preferred to form at lower Fe(Ⅲ)concentrations.While a high concentration of Fe(Ⅲ)would be reduced to Fe(Ⅱ)and consumed the formed PFRs.Adsorption kinetics and X-ray photoelectron spectroscopy analysis indicated that the FBCs effectively enhanced the Cr(Ⅵ)removal efficiency by 1.54-8.20 fold and the Cr(Ⅵ)reduction efficiency by 1.88-9.29 fold compared to those of BC.PFRs quenching and competitive reductant addition experiments revealed that the higher Cr(Ⅵ)reduction performance of FBCs was mainly attributed to the formed PFRs,which could contribute to~74.0%of Cr(Ⅵ)reduction by direct or indirect electron transfer.The PFRs on FBCs surfaces could promote the Fe(Ⅲ)/Fe(Ⅱ)cycle through single electron transfer and synergistically accelerate~52.3%of Cr(Ⅵ)reduction.This study provides an improved understanding of the reduction mechanism of iron-modified biochar PFRs on Cr(Ⅵ)in environments.

关键词： Biochar Iron-modification Cr(Ⅵ) Electron transfer Reduction mechanism

ON EXTRAPOLATION CASCADIC MULTIGRID METHOD

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Journal of Computational Mathematics 2011年第6期29卷 684-697页

作者： Chuanmiao Chen Zhong-Ci Shi Hongling hu Institute of Computation Hunan Normal University Changsha 410081 China LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Based on an asymptotic expansion of （bi）linear finite elements, a new extrapolation formula and extrapolation cascadic multigrid method （EXCMG） are proposed. The key ingredients of the proposed methods are some new extrapolations and quadratic interpolations, which are used to provide better initial values on the refined grid. In the case of triple grids, the errors of the new initial values are analyzed in detail. The numerical experiments show that EXCMG has higher accuracy and efficiency.

关键词： Cascadic multigrid Finite element New extrapolation Error analysis.

Antimony Potassium Tartrate Stabilizes Wide-Bandgap Perovskites for Inverted 4-T All-Perovskite Tandem Solar Cells with Efficiencies over 26%

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Nano-Micro Letters 2023年第7期15卷 204-217页

作者： Xuzhi hu Jiashuai Li Chen Wang Hongsen Cui Yongjie Liu Shun Zhou hongling Guan Weijun Ke Chen Tao Guojia Fang Key Laboratory of Artificial Micro/Nano Structures of Ministry of Education School of Physics and TechnologyWuhan UniversityWuhan 430072People’s Republic of China

Wide-bandgap(WBG)perovskites have been attracting much attention because of their immense potential as a front light-absorber for tandem solar cells.However,WBG perovskite solar cells(PSCs)generally exhibit undesired large open-circuit voltage(VOC)loss due to light-induced phase segregation and severe non-radiative recombination loss.Herein,antimony potassium tartrate(APTA)is added to perovskite precursor as a multifunctional additive that not only coordinates with unbonded lead but also inhibits the migration of halogen in perovskite,which results in suppressed non-radiative recombination,inhibited phase segregation and better band energy alignment.Therefore,a APTA auxiliary WBG PSC with a champion photoelectric conversion efficiency of 20.35%and less hysteresis is presented.They maintain 80%of their initial efficiencies under 100 mW cm^(-2)white light illumination in nitrogen after 1,000 h.Furthermore,by combining a semi-transparent WBG perovskite front cell with a narrow-bandgap tin–lead PSC,a perovskite/perovskite four-terminal tandem solar cell with an efficiency over 26%is achieved.Our work provides a feasible approach for the fabrication of efficient tandem solar cells.

关键词： Perovskite solar cell Tandem Wide bandgap Multifunctional additive

Effect of Fertilization on Anatomical and Physical-mechanical Properties of Neosinocalamus Affinis Bamboo

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Journal of Bioresources and Bioproducts 2019年第1期4卷 67-72页

作者： Jiulong XIE Jinqiu QI Hongling hu Cornelis F DE HOOP hui XIAO Yuzhu CHEN Chungyun HSE College of Forestry Sichuan Agricultural UniversityChengdu 611130China School of Renewable Natural Resource Louisiana State University Agricultural CenterBaton RougeLA70803USA Southern Research Station USDA Forest ServicePinevilleLA71360USA

In order to maintain soil fertility of Neosinocalamus affinis plantations,fertilizers of N,P,and K were applied.The anatomical and physical-mechanical properties of N.affinis bamboo wood from different fertilization treatments were measured.The aim of this study was to elucidate the effect of fertilization practice on the properties of N.affinis bamboo wood.The results revealed that the fertilization of P and K resulted in a slight reduction in fiber length.The application of P,K,and low level(0.3 kg/clump)of N fertilizers had no significant effect on the fiber morphology,while high level(0.9 kg/clump)of N fertilizer contributed to short fibers.The specific gravity was significantly decreased by fertilization,while the volume shrinkage was increased.Since the effect of various fertilization treatments had different influence patterns on the properties of N.affinis,specific evaluations on the quality of the fertilized bamboo wood should be performed prior to its utilization.

关键词： fertilization anatomy physical-mechanical properties Neosinocalamus affinis

The Transfer and Change of Paints in a Hit-and-run Motor Vehicle Accident

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Journal of Forensic Science and Medicine 2024年第1期10卷 24-27页

作者： Can hu Jun Zhu Hongcheng Mei hongling Guo Ping Wang Yajun Li Trace Evidence Department Institute of Forensic ScienceMinistry of Public SecurityXichengBeijingChina

This work investigated transfer and change of paint evidences in a case of hit-and-run.Two kinds of attachments were found on the clothes of the victim and they were initially considered paint fragments from the vehicle causing the accident.Infrared spectroscopy(IR),scanning electron microscope-energy dispersive spectrometer,and Microspectrophotometry were applied for examination of paints and clothing fibers.Polyester was detected in one of the attachments and in the clothing fibers of the victim by IR.A traffic accident simulation experiment was designed and conducted to research whether the polyester attachments come from suspected vehicle paints or victim’s clothing fibers.The results showed that a melt mixture of transferred paints and clothing fiber was formed after a violent collision.Because the amount of transferred paints was too low to be detectable in the mixture,the components detected by IR were mainly from clothing fibers.Thereby,we inferred that only one kind of attachment and paint fragments existed on the clothes of the victim,and the polyester attachments cannot be used to indicate the composition of suspected vehicle paint.Clothing fibers and paints are both common trace evidence in traffic accident cases,and more attention should be paid to the examination of transferred paints on clothing fibers.

关键词： Clothing fibers hit‑and‑run traffic accident infrared spectroscopy paints trace evidence transfer

Global existence of real roots and random Newton flow algorithm for nonlinear system of equations To memorize Qin's method for 770 anniversaries

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Science China Mathematics 2017年第7期60卷 1341-1352页

作者： CHEN ChuanMiao hu hongling Key Laboratory of HPCSIP(Ministry of Education of China) College of Mathematics and Computer ScienceHunan Normal University

To solve nonlinear system of equation,F(x) = 0,a continuous Newton flow x_t(t) = V(x) =-(DF(x))^(-1)F(x),x(0) =x^0 and its mathematical properties,such as the central field,global existence and uniqueness of real roots and the structure of the singular surface,are studied.We concisely introduce random Newton flow algorithm(NFA) for finding all roots,based on discrete Newton flow x^(j+1)=x^j+hV{x^j) with random initial value x^0 and h∈(0,1],and three computable quantities,g_j,d_j and K_j.The numerical experiments with dimension n=300 are provided.

关键词： nonlinear system of equation continuous Newton flow real roots global existence and uniqueness random Newton flow algorithm

Effect of electroacupuncture on brain-derived neurotrophic factor mRNA expression in mouse hippocampus following cerebral ischemia-reperfusion injury

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Journal of Traditional Chinese Medicine 2013年第2期33卷 253-257页

作者： Jianxin Zhao huazhou Xu Yuanxiang Tian Manxiang hu hongling Xiao The Third Hospital Affiliated to Beijing University ofTraditional Chinese Medicine Experiment Center Western Part of Hebei Medical University Institute of Basic Research in Clinical Medicine China Academy of Chinese Medical Sciences Shijiazhuang Hospital of Traditional Chinese Medicine Traditional Chinese Medicine College of Hebei Medical University

OBJECTIVE:This work aims to observe the effects of electroacupuncture on brain-derived neurotrophic factor(BDNF) mRNA expression in mouse hippocampus following cerebral ischemia-reperfusion injury.METHODS:The models of mouse cerebral ischemia-reperfusion injury were established.A total of 96 healthy mice were randomly assigned into 4 groups,namely,the sham surgery,model,model + electroacupuncture,and mode + hydergine groups.Mice in the model + electroacupuncture group were treated through electroacupuncture at the Shenshu(BL 23),Geshu(BL 17),and Baihui(GV 20) acupoints.Mice in the model+hydergine group were intragastrically administered with hydergine(0.77 mg/kg-1 · day-1).The levels of BDNF mRNA expressions in the hippocampus were analyzed through a semi-quantitative reverse transcription-polymerase chain reaction assay on days 1 and 7 after the surgeries.RESULTS:BDNF mRNA expressions in the mouse hippocampus of the model group on days 1 and 7 after the surgery were higher than those of the sham surgery group(both P 0.05).CONCLUSION:Electroacupuncture treatment enhances endogenous BDNF expression,which may improve the survival environment for intracerebral neurons and inhibit the apoptosis of hippocampal cells.

关键词：脑源性神经营养因子 mRNA表达水平海马神经细胞再灌注损伤小鼠模型血症电针治疗损伤模型

Analyses of trends and causes for variations in runoff and sediment load of the Yellow River

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International Journal of Sediment Research 2017年第2期32卷 171-179页

作者： hongling Shi Chunhong hu Yangui Wang Cheng Liu huimei Li State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research International Research and Training Center on Erosion and Sedimentation

Due to the impacts of globe climate change and human activities,dramatic variations in runoff and sediment load were observed for the Yellow River.Analyses of nearly 65 years’ data measured at main hydrologic-stations on the Yellow River from 1950 to 2014 indicated that,except for the Tangnaihai station in the head region,sharp downward trends existed in both the annual runoff and annual sediment load according to the Mann-Kendal trend test;and their abrupt changes occurred in 1986 and in1980,respectively,according to the rank sum test.Factors affecting the changes in the runoff and sediment load were very complicated.Results indicated that the reducing precipitation and the increasing water consumption were the main causes for the runoff decline,while the impoundment of the Longyangxia Reservoir and its combined operation with the Liujiaxia Reservoir exerted a direct bearing on the abrupt change in the annual runoff.In addition to the sediment load decrease associated with the runoff reduction,the reduced storm intensity,the conducted soil erosion control,and the constructed dam buildings all played an important role in the trends and abrupt changes of sediment load decline.

关键词： Yellow River Runoff Sediment load Variation trends