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Acta Mathematicae Applicatae Sinica 2013年第2期29卷 403-414页

作者： Dong-yan. SHI fen.ling WANG yan.min ZHAO Department of Mathematics Zhengzhou University School of Mathematics and Statistics Xuchang University

Quasi-Wilson nonconforming finite element approximation for a class of nonlinear Sobolev equa- tions is discussed on rectangular meshes. We first prove that this element has two special characters by novel approaches. One is that （Vh（U -- Ihu）,VhVh）h may be estimated as order O（h2） when u E H3（Ω）, where Iuu denotes the bilinear interpolation of u, vh is a polynomial belongs to quasi-Wilson finite element space and △h denotes the piecewise defined gradient operator, h is the mesh size tending to zero. The other is that the consistency error of this element is of order O（h2）/O（h3） in broken Hi-norm, which is one/two order higher than its interpolation error when u ε Ha（Ω）/H4 （（1）. Then we derive the optimal order error estimate and su- perclose property via mean-value method and the known high accuracy result of bilinear element. Furthermore, we deduce the global superconvergence through interpolation post processing technique. At last, an extrapola- tion result of order O（h3）, two order higher than traditional error estimate, is obtained by constructing a new suitable extrapolation scheme.

关键词： nonlinear Sobolev equations quasi-Wilson element superclose and superconvergence extrapola-tion

High Accuracy Analysis of the Lowest Order H1-Galerkin Mixed Finite Element Method for Nonlinear Sine-Gordon Equations

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Acta Mathematicae Applicatae Sinica 2017年第3期33卷 699-708页

作者： Dong-yan. SHI fen.ling WANG yan.min ZHAO School of Mathematics and Statistics Zhengzhou UniversityZhengzhou 450001China School of Mathematics and Statistics Xuchang UniversityXuchang 461000China

The lowest order H1-Galerkin mixed finite element method （for short MFEM） is proposed for a class of nonlinear sine-Gordon equations with the simplest bilinear rectangular element and zero order Raviart- Thomas element. Base on the interpolation operator instead of the traditional Ritz projection operator which is an indispensable tool in the traditional FEM analysis, together with mean-value technique and high accuracy analysis, the superclose properties of order O（h2）/O（h2 ＋ r2） in Hi-norm and H（div; Ω）-norm axe deduced for the semi-discrete and the fully-discrete schemes, where h, r- denote the mesh size and the time step, respectively, which improve the results in the previous literature.

关键词： nonlinear sine-Gordon equations H1-Galerkin MFEM superclose estimates semi-discrete and fully-discrete schemes

Infinitely Many Periodic Solutions for a Class of Second-order Hamiltonian Systems

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Acta Mathematicae Applicatae Sinica 2016年第1期32卷 231-238页

作者： Ming-hai yan. Yue-fen.CHEN yan.fang XUE Department of Mathematics Xinyang Normal University

In this paper we study the existence of infinitely many periodic solutions for second-order Hamiltonian systems{ü（t）＋A（t）u（t）＋▽F（t,u（t））=0,u（0）-u（T）=u^·（0）-u^·（T）=0,where F（t,u） is even in u,... 详细信息

关键词： second-order Hamiltonian systems periodic solutions Fountain theorem

Radial Distribution Characteristics of Microstructure and Mechanical Properties of Ti–6Al–4V Butt Joint by Rotary Friction Welding

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Acta Metallurgica Sinica(English Letters) 2015年第10期28卷 1291-1298页

作者： Hai-yan.Chen Li Fu Wen-Yuan Zhang fen.Jun Liu State Key Laboratory of Solidification Processing Northwestern Polytechnical University Shaanxi Key Laboratory of Friction Welding Technologies

Ti-6Al-4V rods were butt-welded by rotary friction welding in this study. Additionally, the radial differences in microstructure and mechanical property of joints were investigated by hierarchy slicing method. The results displayed that the width of weld zone and heat-affected zone of joints became wider along radial direction. Meanwhile, the tensile strength of joints decreased gradually along the radial direction. According to the theoretical analysis, the temperature gradient and inhomogeneous forging pressure leaded to the radial differences. Through K-type thermocouples, the actual temperatures at different locations were measured, and the results were consistent with the theoretical analysis. Theoretically, the radial differences of rotary friction welding joint are an inherent phenomenon; thus, the size of weldment should be limited strictly below the corresponding critical size. In order to prevent radial differences from enlarging, the welding surface profile of weldment can be processed into oval shape, and a larger forging pressure can be used within the scope of the joint deformation allowed according to causes for radial differences.

关键词： Titanium alloys Friction welding Microstructure Mechanical property

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高等教育数字化转型与教育理念的关系研究

教育教学论坛 2024年第31期 29-32页

作者：燕小斌顾玉芬卢学峰兰州理工大学材料科学与工程学院甘肃兰州730050

随着数字技术在高等教育领域的广泛应用和深度融合,高等教育必然面临着数字化转型的新机遇,通过对当今高等教育教学中不同层次的数字化转型实践与发展现状进行系统分析,主要对数字化转型实践中所呈现出的新型教学关系背后的教育理念进... 详细信息

随着数字技术在高等教育领域的广泛应用和深度融合,高等教育必然面临着数字化转型的新机遇,通过对当今高等教育教学中不同层次的数字化转型实践与发展现状进行系统分析,主要对数字化转型实践中所呈现出的新型教学关系背后的教育理念进行深入分析与探讨,分析研究表明高等教育教学的数字化转型解构了以知识传授为先的传统教育理念,助推了契合信息时代的以学为中心的高等教育理念的重塑与构建,因此,高等教育的数字化转型是信息时代里高等教育高质量发展值得深入推进的重要路径和新方向。

关键词：高等教育数字化转型以学为中心

模拟牲畜采食对高寒草甸土壤潜在氧化亚氮排放的影响

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草地学报 2024年第9期32卷 2794-2802页

作者：吴晓芬陈有超蒋文婷沈玉叶蔡延江浙江农林大学省部共建亚热带森林培育国家重点实验室浙江杭州311300 浙江农林大学环境与资源学院/碳中和学院浙江杭州311300

探明牲畜采食对土壤氧化亚氮(N_(2)O)排放的影响,是准确预测放牧干扰下高寒草甸生态系统温室气体变化的关键。本研究通过刈割留茬模拟牲畜不同强度采食行为(无采食,CK;轻度采食,LD:留茬高度3 cm;重度采食,HD:留茬高度<1 cm),利用室内培... 详细信息

探明牲畜采食对土壤氧化亚氮(N_(2)O)排放的影响,是准确预测放牧干扰下高寒草甸生态系统温室气体变化的关键。本研究通过刈割留茬模拟牲畜不同强度采食行为(无采食,CK;轻度采食,LD:留茬高度3 cm;重度采食,HD:留茬高度<1 cm),利用室内培养法测定土壤潜在N_(2)O排放,并测定了土壤理化性质、酶活性以及硝化和反硝化功能基因丰度等指标。结果表明:LD处理对土壤潜在N_(2)O排放无显著影响,但HD处理显著降低了潜在N_(2)O排放(P<0.05)。重度采食导致输入土壤铵态氮(NH+4-N)和碳减少,降低土壤AOA-amoA,nirS和nosZI基因丰度及反硝化潜势(Denitrification potential,DP),减弱土壤硝化和反硝化作用从而降低N_(2)O排放。综上,轻度采食对土壤潜在N_(2)O排放无显著影响,但重度采食可能通过降低土壤硝化和反硝化作用,减弱土壤潜在N_(2)O排放。

关键词：高寒草甸硝化作用反硝化作用放牧

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Combining electroacupuncture and transcranial direct current stimulation as an adjuvant therapy enhances spontaneous conversation and naming in subacute vascular aphasia:A retrospective analysis

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Journal of Integrative Medicine 2022年第3期20卷 244-251页

作者： Samwel Sylvester Msigwa yan.Li Xiang-lin Cheng fen.Cao Department of Neurology the Clinical Medicine School of Yangtze Universitythe First Affiliated Hospital of Yangtze UniversityJingzhou 424023Hubei ProvinceChina Department of Research and Training Mirembe National Mental Health HospitalP.O.Box 910DodomaTanzania Department of Rehabilitation The First Affiliated Hospital of Yangtze UniversityJingzhou 424023Hubei ProvinceChina

Objective:Emerging evidence shows the effectiveness of speech and language therapy(SLT);however,precise therapeutic parameters remain *** for the use of adjunctive transcranial direct current stimulation(t DCS)to treat post-stroke aphasia(PSA)is promising;however,the utility of combining t DCS and electroacupuncture(EA)has not yet been *** study assessed the therapeutic consequences of EA and t DCS coupled with SLT in subacute PSA patients who were also undergoing hyperbaric oxygen therapy(HBOT).Methods:A retrospective analysis was conducted on subacute(<6 months)PSA patients who were divided into three groups:patients who received EA plus t DCS(acupuncture group),patients who underwent t DCS(t DCS group),and patients who experienced conventional therapy(HBOT+SLT).All subjects underwent 21 days of treatment and also received conventional *** aphasia battery of Chinese(ABC)was used to score pre-and post-intervention ***:The analysis comprised 238 *** infarction was the most frequent stroke type(137[57.6%]),while motor(66[27.7%])and global aphasia(60[25.2%])were the most common types of *** 21 days of intervention,the ABC scores of all patients were *** acupuncture group had the highest ABC scores,but only repetition,naming,and spontaneous speech were statistically improved(P<0.01).Post-hoc tests revealed significant improvement in word retrieval in the acupuncture and t DCS groups(P<0.01,P=0.037),while the acupuncture group had additional significant improvement in spontaneous conversation(P<0.01).Conclusion:Combining acupuncture and t DCS as an adjuvant therapy for subacute PSA led to significant spontaneous speech and word retrieval *** prospective,multi-ethnic,multi-center trials are warranted.

关键词： Aphasia Stroke rehabilitation Acupuncture Electroacupuncture Transcranial direct current stimulation Speech therapy

气相色谱-质谱法测定食品接触材料及制品中4种癸二酸酯类化合物迁移量

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质谱学报 2024年第4期45卷 558-566,I0005页

作者：陈湘颖曾铭阿文伟范莹颖曾莹陈燕芬李丹钟怀宁郑建国广州海关技术中心广东广州510623

本研究建立了气相色谱-质谱(GC-MS)法同时测定食品接触材料及制品中癸二酸二正丁酯、癸二酸二(2-乙基己基)酯、癸二酸二异辛酯和癸二酸二(2,2,6,6-四甲基-4-哌啶)酯等4种癸二酸酯类化合物在食品模拟物及化学替代溶剂中的迁移量。对于化... 详细信息

本研究建立了气相色谱-质谱(GC-MS)法同时测定食品接触材料及制品中癸二酸二正丁酯、癸二酸二(2-乙基己基)酯、癸二酸二异辛酯和癸二酸二(2,2,6,6-四甲基-4-哌啶)酯等4种癸二酸酯类化合物在食品模拟物及化学替代溶剂中的迁移量。对于化学替代溶剂95%乙醇和异辛烷,采用直接液体进样法;对于橄榄油食品模拟物,用乙腈萃取后采用基质分散萃取净化后上机测试;对于其他食品模拟物(水、4%乙酸、10%乙醇、20%乙醇和50%乙醇),采用正己烷萃取后上机测试。在优化的实验条件下,4种化合物的分离效果良好,在0.30~5.0 mg/kg和0.50~5.0 mg/kg浓度范围内分别呈良好的线性关系,相关系数(r2)大于0.995;4种癸二酸酯类化合物迁移量的检出限和定量限分别为0.1~0.2、0.3~0.5 mg/kg。对塑料样品水、4%乙酸、10%乙醇、20%乙醇、50%乙醇、95%乙醇和异辛烷浸泡液进行0.30、2.0、4.0 mg/kg 3个浓度水平的添加实验,对橄榄油浸泡液进行0.50、2.0、4.0 mg/kg 3个浓度水平的添加实验,测得加标回收率在92.5%~108%之间,相对标准偏差(RSD)在2.4%~8.8%之间。本方法灵敏度高、精密度和准确度好,能够满足食品接触材料及制品中4种癸二酸酯类化合物迁移量的检测需求。

关键词：气相色谱-质谱(GC-MS) 食品接触材料及制品癸二酸酯迁移

Evaluating Water Withdrawals for Regional Water Management Under a Data-driven Framework

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Chinese Geographical Science 2022年第3期32卷 521-536页

作者： LU yan.WANG Jinxin LIU Jianzhong QIN fen.WANG Jiayao School of Geoscience and Technology Zhengzhou UniversityZhengzhou 450001China Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions Ministry of EducationHenan UniversityZhengzhou 475000China Henan Industrial Technology Academy of Spatio-Temporal Big Data Henan UniversityZhengzhou 475000China College of Geography and Environmental Science Henan UniversityKaifeng 475004China

With an increase in population and economic development,water withdrawals are close to or even exceed the amount of water available in many regions of the *** water withdrawals could help water planners improve the efficiency of water use,water resources allocation,and management in order to alleviate water ***,minimal information has been obtained on how water withdrawals have changed over space and time,especially on a regional or local *** research proposes a data-driven framework to help estimate county-level distribution of water *** this framework,spatial statistical methods are used to estimate water withdrawals for agricultural,industrial,and domestic purposes in the Huaihe River watershed in China for the period 1978–*** water withdrawals were found to have more than doubled,from 292.55×10^(8)m^(3) in 1978 to 642.93×10^(8)m^(3) in 2009,and decreased to 602.63×10^(8)m^(3) in *** water increased from 208.17×10^(8)m^(3) in 1978 to 435.80×10^(8)m^(3) in 2009 and decreased to 360.84×10^(8)m^(3) in *** and domestic water usage constantly increased throughout the 1978–2018 *** 1978,industrial and domestic demands were 20.35×10^(8)m^(3) and 60.04×10^(8)m^(3),respectively,and up until 2018,the figures were 105.58×10^(8)m^(3) and 136.20×10^(8)m^(3).From a spatial distribution perspective,Moran’s I statistical results show that the total water withdrawal has significant spatial autocorrelation during 1978–*** overall trend was a gradual increase in 1978–2010 with withdrawal beginning to decline in 2010–*** results of Getis-Ord G_(i)^(*)statistical calculations showed spatially contiguous clusters of total water withdrawal in the Huaihe River watershed during1978–2010,and the spatial agglomeration weakened from 2010 to *** study provides a data-driven framework for assessing water withdrawals to enable a deeper understanding of competing water use among economic sectors a

关键词： water withdrawal data-driven framework spatial data analysis water coefficient Huaihe River watershed,China

Integrating Remote Sensing and Proximal Sensors for the Detection of Soil Moisture and Salinity Variability in Coastal Areas

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Journal of Integrative Agriculture 2013年第4期12卷 723-731页

作者： GUO yan.SHI Zhou ZHOU Lian-qing JIN Xi TIAN yan.fen. TENG Hong-fen Institute of Agricultural Remote Sensing and Information Technology Application College of Environmental and Resource Sciences Zhejiang University

Soil moisture and salinity are two crucial coastal saline soil variables, which influence the soil quality and agricultural productivity in the reclaimed coastal region. Accurately characterizing the spatial variability of these soil parameters is critical for the rational development and utilization of tideland resources. In the present study, the spatial variability of soil moisture and salinity in the reclaimed area of Hangzhou gulf, Shangyu City, Zhejiang Province, China, was detected using the data acquired from radar image and the proximal sensor EM38. Soil moisture closely correlates radar scattering coefficient, and a simplified inversion model was built based on a backscattering coefficient extracted from multi-polarization data of ALOS/PALSAR and in situ soil moisture measured by a time domain reflectometer to detect soil moisture variations. The result indicated a higher accuracy of soil moisture inversion by the HH polarization mode than those by the HV mode. Soil salinity is reflected by soil apparent electrical conductivity （ECa）. Further, ECa can be rapidly detected by EM38 equipment in situ linked with GPS for characterizing the spatial variability of soil salinity. Based on the strong spatial variability and interactions of soil moisture and salinity, a cokriging interpolation method with auxiliary variable of backscattering coefficient was adopted to map the spatial variability of ECa. When compared with a map of ECa interpolated by the ordinary kriging method, detail was revealed and the accuracy was increased by 15.3%. The results conclude that the integrating active remote sensing and proximal sensors EM38 are effective and acceptable approaches for rapidly and accurately detecting soil moisture and salinity variability in coastal areas, especially in the subtropical coastal zones of China with frequent heavy cloud cover.

关键词： remote sensing proximal sensor soil moisture salinity backscattering coefficient soil apparent electricalconductivity (ECa)