Table of Content

25 November 2017, Volume 37 Issue 6

Previous Issue    Next Issue

Ansys simulation analysis of cement concrete pavement bearing capacity under extra heavy load

YANG Sanqiang,WU Wenxiu,LIU Na,FAN Xiaoyu

2017, 37(6):  561-566.  DOI: 10.3969/j.issn.1000-1565.2017.06.001

Asbtract ( 621 )   PDF (1738KB) ( 527 )  

References | Related Articles | Metrics

The finite element model of small deflection elastic thin plate was used to carry out the numerical simulation analysis of the bearing capacity by means of dynamic detection, automatic dropping hammer and other testing methods.The results show that the maximum deformation of cement concrete pavement on the wheel is between 0.375 4—0.657 9 mm at the same special heavy load, different thickness and different strength grades. The maximum deformation of the road surface at the wheel will be significantly reduced when the thickness of concrete slab is 10—25 cm and the strength is C30—C50. Thick concrete slab of C40 and 25 cm is used according to the life of the road design cycle. The results can provide theoretical support for the design of cement concrete pavement under extra heavy loads.

Hepatitis B virus infection model with vertical transmission and infection period

TAO Yujie,FENG Heping

2017, 37(6):  567-571.  DOI: 10.3969/j.issn.1000-1565.2017.06.002

Asbtract ( 572 )   PDF (935KB) ( 298 )  

References | Related Articles | Metrics

Hepatitis B virus infection model with vertical transmission and infection period were studied.By consider the epidemic models with nonlinear incidence rate,making infection period as time delay,and making use of Routh-Hurwite criterion to prove that condition of disease-free equilibrium is local asymptotic stability,we obtained a basic reproductive number R₀ and proved the global asymptotic stability of endemic equilibrium by using the Lyapunov functional method.

Stable nucleus size of silicon nanoparticles prepared by pulsed-laser deposition

QIN Aili,CHU Lizhi,DENG Zechao,DING Xuecheng,WANG Yinglong

2017, 37(6):  572-576.  DOI: 10.3969/j.issn.1000-1565.2017.06.003

Asbtract ( 389 )   PDF (1540KB) ( 361 )  

References | Related Articles | Metrics

The dynamical process of silicon nanoparticles prepared by pulsed-laser deposition was simulated using Monte Carlo simulation method.In the simulation,the nucleation and growth model was adopted and the number of silicon atoms contained in the stable nucleus were studied during nanoparticles formation at room temperature.After extensive calculations and comparisons with the experimental data,it was found that the average size distribution of silicon nanoparticles was in good agreement with the experimental data when the number of silicon atoms in the stable nucleus was 6.

Design of staggered step parallax barrier for LED autostereoscopic display system

LI Wenhua,ZHANG Zhiwen,SUN Yabo,ZHAO Xiaohui,ZHANG Lianshui,DANG Wei

2017, 37(6):  577-583.  DOI: 10.3969/j.issn.1000-1565.2017.06.004

Asbtract ( 545 )   PDF (1794KB) ( 301 )  

References | Related Articles | Metrics

The structure of parallax barrier is the key part of parallax barrier LED autostereoscopic display system.A new staggered step parallax barrier was designed to improve the performance of parallax barrier LED autostereoscopic display system.Simulation results by Tracepro software show staggered step parallax barrier can effectively separate images from different viewpoints,and fit to the setup of parallax barrier LED autostereoscopic display system.Experimental results also verify that staggered step parallax barrier can balance the Moire fringe minimization and suppression of the crosstalk of images from different viewpoints.With respect to Moire fringe,the performance of staggered step parallax barrier is better than that of traditional step parallax barrier.With respect to crosstalk suppression,the performance of staggered step parallax barrier is better than that of slanted parallax barrier.

Effect of preparation temperature on corrosion resistance of iron oxides coated aluminum pigments

MA Zhiling,ZHANG Chunyan,WEN Yajing

2017, 37(6):  584-589.  DOI: 10.3969/j.issn.1000-1565.2017.06.005

Asbtract ( 474 )   PDF (2076KB) ( 323 )  

References | Related Articles | Metrics

The khaki waterborne aluminum pigments were prepared in isopropyl alcohol/water media at 6-6.5 pH value,using ferrous sulfate as precursor and H₂O₂ as anchoring agent.The encapsulated mechanism and the effect of temperature on the aluminum property were discussed.Scanning electron microscopy,optical microscopy,X-ray diffraction and infrared spectroscopy results show that the diaspore form on the aluminum flakes surface by H₂O₂ oxidizing,and the amorphous iron oxide particles with opposite charge can combine with diaspore by mutual attraction.Perhaps the diaspore induces the iron oxide in the solution to form goethite anchored on the aluminum surface and then form a dense coating layer.At low temperature,the electrostatic attraction of amorphous iron oxide dominates.As the temperature rising,the proportion of goethite is increased,and the crystallinity is enhanced.The performance test prove that goethite and amorphous iron oxide evenly deposits on the aluminum surface together to form a dense coating layer at 45 ℃,and thus gives the khaki aluminum pigments excellent corrosion resistance performance.

Electrochemical performance of SnO₂-NiO porous nano-fiber anode materials

YANG Qi,WANG Na,CUI Shuai,YANG Lu

2017, 37(6):  590-594.  DOI: 10.3969/j.issn.1000-1565.2017.06.006

Asbtract ( 464 )   PDF (1363KB) ( 405 )  

References | Related Articles | Metrics

SnO₂-NiO porous nano-fibers were synthesized by annealing nano-fibers produced by electrospinning a solution containing polyacrylonitrile(PAN),precursors of SnO₂ and NiO.XRD,SEM,TEM,nitrogen adsorption-desorption,cyclic voltammetry(CV)and charge-discharge testing were performed to analyze their morphologies,crystal structures,pore structures and electrochemical performance.The results show the porous nano-fibers consist of tetragonal phase SnO₂ and cubic phase NiO nano-particles with a size of ~5 nm; the pore size between nano-particles is ~5 nm; the nano-fiber anodes exhibit excellent electrochemical performance with a reversible capacity of 637 mA h/g after 100 cycles at a current density of 50 mA/g without exhibiting apparent capacity fading and a reversible capacity of 505 mA·h/g at a high current density up to 800 mA/g.Their excellent electrochemical performance is attributed to their one dimensional porous structure.

First principle study of the B-site ordered structure perovskite BaFe_0.5Nb_0.5O₃

JI Denghui,ZHANG Ya,WANG Shuling,LI Xiuling,ZHANG Congmin,ZENG Zhiwei

2017, 37(6):  595-604.  DOI: 10.3969/j.issn.1000-1565.2017.06.007

Asbtract ( 669 )   PDF (2313KB) ( 591 )  

References | Related Articles | Metrics

Based on the first principle calculations,the four kinds of B-site order or disorder BaFe_0.5Nb_0.5O₃ were constructed using the CASTEP software package,the impacts of the order and disorder at B sites on the structure and physical properties of the BaFe_0.5Nb_0.5O₃ perovskite were investigated.The exchange-correlation potential with Perdew-Burke-Ernzerhof(PBE)gradient corrected functional is adopted.Calculated results show that the antiferromagnetic configuration exhibits the direct band with a minimum- DOI:10.3969/j.issn.1000-1565.2017.06.007基于第一性原理的钙钛矿BaFe_0.5Nb_0.5O₃B位的有序结构纪登辉¹,张娅¹,王淑玲²,李秀玲³,张聪敏¹,曾志伟¹(1.六盘水师范学院 电气工程学院,六盘水市光电信息技术重点实验室,贵州 六盘水 553004;2.河北工程大学 数理科学与工程学院,河北 邯郸 056038;3.河北师范大学 物理科学与信息工程学院,河北省新型薄膜材料实验室,河北 石家庄 050024)摘 要:基于第一性原理,利用Materials Studio计算软件中CASTEP软件包构建出双钙钛矿材料BaFe_0.5Nb_0.5O₃的4种位形,研究B位有序无序对其结构和物理性能的影响.通过GGA+PBE关联函数对4种位形结构分别进行几何优化和能量优化,根据能量最低原理,获得最终优化后的几何结构与各项物理性能.计算结果表明:反铁磁的能量最低且为半导体,为最优的几何结构,并且通过紫外可见吸收实验证明了带隙的存在;铁磁结构与反铁磁结构自旋存在夹角,属于半金属;在费米能级附近,d电子与p电子的相互作用明显,对态密度的贡献最大;在低频率范围内,反铁磁结构Ba-AFM出现吸收峰最早,但吸收峰强度最低.关键词:双钙钛矿;第一性原理;带隙;能量最低原理;态密度中图分类号:O469 文献标志码:A 文章编号:1000-1565(2017)06-0595-10First principle study of the B-site ordered structureperovskite BaFe_0.5Nb_0.5O₃JI Denghui¹,ZHANG Ya¹,WANG Shuling²,LI Xiuling³,ZHANG Congmin¹,ZENG Zhiwei¹(1.The Key Laboratory of Opt-electrical InformationTechnology of Liupanshui City,School of Physics and Electronic Science,Liupanshui Normal University,Liupanshui 553004,China;2.School of Science of Hebei University of Engineering,Hebei University of Engineering,Handan 056038,China;3.Hebei Advanced Thin Films Laboratory,College of Physics andInformation Engineering,Hebei Normal University,Shijiazhuang 050024,China)Abstract: Based on the first principle calculations,the four kinds of B-site order or disorder BaFe_0.5Nb_0.5O₃ were constructed using the CASTEP software package,the impacts of the order and disorder at B sites on the structure and physical properties of the BaFe_0.5Nb_0.5O₃ perovskite were investigated.The exchange-correlation potential with Perdew-Burke-Ernzerhof(PBE)gradient corrected functional is adopted.Calculated results show that the antiferromagnetic configuration exhibits the direct band with a minimum- 收稿日期:2016-06-11 基金项目:国家自然科学基金资助项目(11504078); 六盘水师范学院高层次人才科研启动基金(LPSSYKYJJ201404);贵州省教育厅自然科学重点研究项目(KY2015379); 六盘水师范学院MIT创新团队项目(LPSSYKJTD201402);六盘水师范学院物理电子学院级重点学科(LPSSYZDXK201502);贵州省科技厅联合基金(LH［2014］7449,LH［2014］7456) 第一作者:纪登辉(1985—),男,河北平泉人,六盘水师范学院讲师理学博士,主要从事磁性纳米功能材料研究.E-mail:jidenghui2007@163.com第6期纪登辉等:基于第一性原理的钙钛矿BaFe_0.5Nb_0.5O₃B位的有序结构energy,which is consistent with the Uv-vis absorption experiment result.Near the Fermi level,the interaction between d and p electron contributes the most to the density of states.At the low frequency range,antiferromagnetic configuration possesses the lowest absorption peak location,and the weakest intensity.

Prokaryotic expression and characterization of ρ-hydroxyphenylpyruvate dioxygenase from cultured Coptis japonica cells

LIANG Yuling,SATO Fumihiko

2017, 37(6):  605-613.  DOI: 10.3969/j.issn.1000-1565.2017.06.008

Asbtract ( 518 )   PDF (1613KB) ( 326 )  

References | Related Articles | Metrics

To characterize the ρ-hydroxyphenylpyruvate dioxygenase from cultured Coptis japonica cells(CjHPPD),recombinant protein was produced in E.coli. When the enzyme activity of recombinant CjHPPD was measured in vitro,the formation of homogentisate was determined by HPLC and confirmed by LC-MS analysis. Enzyme assays indicated that the optimum pH for the reaction of HPP transfer to homogentiaste was approximately 6.5. A time course study showed that the accumulation of homogentisate was linear with time for at least 10 min in the presence of 10 μL(37.18 μg)of desalted enzyme and 200 μmol/L hydroxyphenlpyruvate. The optimum temperature was 30 ℃. Characterization of the substrate affinity of recombinant CjHPPD using HPP as the substrate indicated that CjHPPD also followed Michaelis-Menten-type kinetics and K_m was estimated to be 43.2 μmol/L. The K_m of CjHPPD was much higher than the reported values for the HPPD enzyme from other plants. Since HPPD inhibitors are known to compete for the substrate for binding,the higher K_m value of HPP might affect herbicide tolerance.- DOI:10.3969/j.issn.1000-1565.2017.06.008黄连对羟苯基丙酮酸双加氧酶的原核表达和酶学性质梁玉玲^1,2,佐藤文彦³(1.河北大学 生命科学学院,河北 保定 071002;2.河北省生物工程技术研究中心,河北 保定 071002;3. 京都大学 大学院,日本 京都 606-8502)摘 要:为了研究黄连对羟苯基丙酮酸双加氧酶(CjHPPD)的功能和性质,在E.coli中异源表达其编码cDNA得到了重组的CjHPPD. 经HPLC和LC-MS检测确定重组CjHPPD具有催化对羟苯基丙酮酸形成尿黑酸的酶活性.酶学特性分析表明,CjHPPD催化尿黑酸形成的最适pH值为6.5,产物尿黑酸的积累至少在反应开始10 min内随时间呈线形增长,最适反应温度为30 ℃.以ρ-HPP为底物进行底物亲和性分析表明,CjHPPD符合Michaelis-Menten动力学曲线,K_m值为43.2 μmol/L.结果表明,CjHPPD的K_m值明显高于其他已报道的植物HPPD的K_m值,高K_m使得CjHPPD具有较强除草剂抗性.关键词:黄连;对羟苯基丙酮酸双加氧酶;原核表达;酶学性质;K_m值中图分类号:Q786 文献标志码:A 文章编号:1000-1565(2017)06-0605-09Prokaryotic expression and characterization of ρ-hydroxyphenylpyruvatedioxygenase from cultured Coptis japonica cellsLIANG Yuling^1,2,SATO Fumihiko³(1.College of Life Sciences,Hebei University,Baoding 071002,China;2.Biological Engineering Technology Research Center in Hebei Province,Baoding 071002,China;3.Graduate School of Biostudies,Kyoto University,Kyoto 606-8502,Japan)Abstract: To characterize the ρ-hydroxyphenylpyruvate dioxygenase from cultured Coptis japonica cells(CjHPPD),recombinant protein was produced in E.coli. When the enzyme activity of recombinant CjHPPD was measured in vitro,the formation of homogentisate was determined by HPLC and confirmed by LC-MS analysis. Enzyme assays indicated that the optimum pH for the reaction of HPP transfer to homogentiaste was approximately 6.5. A time course study showed that the accumulation of homogentisate was linear with time for at least 10 min in the presence of 10 μL(37.18 μg)of desalted enzyme and 200 μmol/L hydroxyphenlpyruvate. The optimum temperature was 30 ℃. Characterization of the substrate affinity of recombinant CjHPPD using HPP as the substrate indicated that CjHPPD also followed Michaelis-Menten-type kinetics and K_m was estimated to be 43.2 μmol/L. The K_m of CjHPPD was much higher than the reported values for the HPPD enzyme from other plants. Since HPPD inhibitors are known to compete for the substrate for binding,the higher K_m value of HPP might affect herbicide tolerance.- 收稿日期:2017-05-26 基金项目:河北省自然科学基金资助项目(C2013201126) 第一作者:梁玉玲(1965—),女,河北定州人,河北大学教授,主要从事植物分子生物学与基因工程研究.E-mail: yuling_liang@163.com第6期梁玉玲等:黄连对羟苯基丙酮酸双加氧酶的原核表达和酶学性质

Callus proliferation and accumulation of tea polyphenols of Anji Baicha

LIN Yuxing,XIAO Zefeng,TIAN Birui,HAO Na,WANG Junli

2017, 37(6):  614-620.  DOI: 10.3969/j.issn.1000-1565.2017.06.009

Asbtract ( 508 )   PDF (1020KB) ( 289 )  

References | Related Articles | Metrics

For utilization of Anji Baicha,the effects of different plant growth regulators on callus,proliferation and accumulation of tea polyphenols of Anji Baicha were investigated using leaf as explants.The results showed that TDZ was more effective for callus induction,proliferation and accumulation of tea polyphenols.The callus induction frequency reached 92.1 % when the concentration of TDZ was as high as 1.0 mg/L.The mass fraction of tea polyphenols was 20.6%,and the relative abundance of epicatechin increased to 5.3%.

Screening of Bacillus strains producing β-glucosidase and study on hydrolysis of soybean isoflavone glycosides

LIU Hongli,GUO Xiaojun,DI Congying,GUO Wei,ZHU Baocheng

2017, 37(6):  621-629.  DOI: 10.3969/j.issn.1000-1565.2017.06.010

Asbtract ( 514 )   PDF (1642KB) ( 406 )  

References | Related Articles | Metrics

In order to obtain Bacillus strains capable of efficiently hydrolyze soybean isoflavone glycosides,this study screened Bacillus strains producing β-glucosidase from fresh feces of animals with the help of Aesculin separation culture medium.Then the strains with relatively higher β-glucosidase activity were identified and the ability of hydrolyzing isoflavone glucosides were studied.The results showed that a strains of Bacillus R2-2 with relatively higher β-glucosidase activity was screened out.The identity of strains R2-2 was Bacillus amyloliquefaciens.Strain R2-2 showed rather high efficiency in hydrolyzing isoflavone glucosides.The daidzin hydrolysis rate reached 53.65%,and genistin hydrolysis rate was 48.80%.

Assessment of ecological security for Shuifeng Lake based on the DPSIR model

DONG Dianbo,SUN Xuekai,WEI Yawei,WANG Wei

2017, 37(6):  630-639.  DOI: 10.3969/j.issn.1000-1565.2017.06.011

Asbtract ( 475 )   PDF (1409KB) ( 296 )  

References | Related Articles | Metrics

In order to assess ecological security state of Shuifeng Lake basin scientifically,based on relevant statistical data and research findings,according to the DPSIR(driving force-pressure-state-impact-risk)model,an ecological security index(ESI)system of Shuifeng Lake was constructed from 4 aspects including the social and economic impact,water ecological health,ecological service,management and control,and the assessing system was built by 4 major items which include 33 indices.The result showed that the ESI was gradually increased from 2014 to 2016 and the assessment of ecological security of Shuifeng Lake basin was in good condition.To maintain the ecological security condition,a lot of measures must be taken from- DOI:10.3969/j.issn.1000-1565.2017.06.011基于DPSIR模型的水丰湖生态安全评估董殿波¹,孙学凯²,魏亚伟³,王炜⁴(1.辽宁省环境科学研究院 辽河研究中心,辽宁 沈阳 110161;2.中国科学院沈阳应用生态研究所大青沟沙地生态实验站,辽宁 沈阳 110016;3.沈阳农业大学 林学院,辽宁 沈阳 110866;4.辽宁省大气污染防治管理中心 大气管理室,辽宁 沈阳 110161)摘 要:为了科学合理评估水丰湖生态安全状况,在相关统计数据和研究基础上,基于DPSIR(驱动力-压力-状态-影响-响应)框架模型,从社会经济影响、水生态健康、生态服务功能、调控管理4个方面,选择了4个大项,33个小项构建了水丰湖生态安全评估指标体系.评估结果表明:2014—2016年,水丰湖流域生态安全指数(ESI)逐步升高,水丰湖生态安全大体上位于良好水平范围.但要维持生态安全水平不下降,需要制定多方面的措施.加强环保的力度,阻止破坏生态环境,完善湖泊环境基础设施建设,建立湖泊环境治理和监管体系,是提高湖泊生态安全,实现水丰湖流域可持续发展的重要途径.关键词:水丰湖;DPSIR模型;生态安全中图分类号:X824 文献标志码:A 文章编号:1000-1565(2017)06-0630-10Assessment of ecological security for ShuifengLake based on the DPSIR modelDONG Dianbo¹,SUN Xuekai²,WEI Yawei³,WANG Wei⁴(1.Liaohe River Research Center,Liaoning Academy of Environmental Sciences,Shenyang110161,China;2.Daqinggou Ecological Station,Institute of Applied Ecology,Chinese Academyof Sciences,Shenyang 110016,China; 3.College of Forestry,Shenyang Agricultural University,Shenyang 110866,China; 4.Air Management Department,Liaoning Air Pollution Prevention andControl Management Center,Shenyang 110161,China)Abstract: In order to assess ecological security state of Shuifeng Lake basin scientifically,based on relevant statistical data and research findings,according to the DPSIR(driving force-pressure-state-impact-risk)model,an ecological security index(ESI)system of Shuifeng Lake was constructed from 4 aspects including the social and economic impact,water ecological health,ecological service,management and control,and the assessing system was built by 4 major items which include 33 indices.The result showed that the ESI was gradually increased from 2014 to 2016 and the assessment of ecological security of Shuifeng Lake basin was in good condition.To maintain the ecological security condition,a lot of measures must be taken from- 收稿日期:2017-04-24 基金项目:辽宁省自然科学基金资助项目(2015020594);国家自然科学基金资助项目(41401262) 第一作者:董殿波(1981—),男,辽宁绥中人,辽宁省环境科学研究院高级工程师,主要从事污染生态方面的研究.E-mail:dianbo99-21@163.com 通信作者:孙学凯(1980—),男,辽宁沈阳人,中国科学院沈阳应用生态研究所工程师,主要从事生态恢复与环境污染控制、生态系统碳氮养分循环的研究.E-mail: sunxuekai@iae.ac.cn第6期董殿波等:基于DPSIR模型的水丰湖生态安全评估multi-aspects.Strengthening environmental protection,preventing the destruction of ecological environment,improving the lake environmental infrastructure construction and establishing lake environmental management and supervision system are important ways to improve the ecological security and realize the sustainable development of the Shuifeng Lake basin.

Convolutional neural network and its research advances

ZHAI Junhai,ZHANG Sufang,HAO Pu

2017, 37(6):  640-651.  DOI: 10.3969/j.issn.1000-1565.2017.06.012

Asbtract ( 863 )   PDF (1277KB) ( 962 )  

References | Related Articles | Metrics

Deep learning is the most popular research topic in the field of machine learning,AlphaGo which overwhelmingly impacts the world is trained with deep learning algorithms.Convolution neural network(CNN)is a model trained with deep learning algorithm,CNN is widely and successfully applied in computer version.The main purpose of this paper includes two aspects:one is to provide readers with some insights into CNN including its architecture,related concepts,operations and its training; the other is to present a comprehensive survey on research advances of CNN,mainly focusing on 4 aspects: activation functions,pooling,training and applications of CNN.Furthermore,the emerging challenges and hot research topics of CNN are also discussed.This paper can be very helpful to researchers in related field.

A retrieval model of scientific documents based on mathematical expression features

TIAN Xuedong,CUI Xiaojuan

2017, 37(6):  652-661.  DOI: 10.3969/j.issn.1000-1565.2017.06.013

Asbtract ( 583 )   PDF (1718KB) ( 379 )  

References | Related Articles | Metrics

The existing full-text retrieval techniques are mostly targeting the text information.While the retrieval of the scientific documents with mathematical expressions as the main components is still in the exploration stage.In order to make the users can easily use the mathematical formula as the query language to retrieve the scientific and technical documents,a new scientific document retrieval model based on mathematical expression features was proposed.Firstly,the formulas were resolved into the subformulas forming the binary trees,which are used to generate the retrieval feature vectors.In the index phase,the index table with the hierarchical structure was constructed using the extracted document feature vectors.In the retrieval phase,the document vectors were weighted by tf-idf.The similarity between the retrieval vector and the document vector was calculated by using the cosine similarity,and an ordered document retrieval result was obtained.The experiment data was selected from different journals,academic website and public data set of 5 017 science and technology documents which contain 96 362 mathematical formulas.The average retrieval time was 0.428 s,which indicates that the proposed model achieved- DOI:10.3969/j.issn.1000-1565.2017.06.013基于数学表达式特征的科技文档检索模型田学东,崔晓娟(河北大学 计算机科学与技术学院,河北 保定 071002)摘 要:现有全文检索技术多是以文本信息为处理对象,对于以数学表达式为主要成分的科技文档检索还处在探索阶段.为了使用户可以方便地以数学公式作为查询语言对科技文档进行检索,提出了一种基于数学表达式特征的科技文档检索模型.首先通过将公式解析为二叉树得到数学表达式的子式信息,利用数学表达式及子式构造检索特征向量;在索引阶段,利用所提取的文档特征向量构建分层结构的索引表;在匹配阶段,对文档向量采用tf-idf进行加权操作,利用余弦相似度对检索向量和文档向量进行相似度计算,得到一个有序的文档检索结果.实验选取了来自不同领域的期刊、学术网站以及公共数据集的5 017篇科技文档,其中包含了96 362条数学公式,平均检索时间为0.428 s,表明该模型达到了实现较高效率科技文档检索的目标.关键词:科技文档;数学表达式;检索;索引;匹配;二叉树;特征中图分类号:TP391 文献标志码:A 文章编号:1000-1565(2017)06-0652-10A retrieval model of scientific documents based onmathematical expression featuresTIAN Xuedong,CUI Xiaojuan(College of Computer Science and Technology,Hebei University,Baoding 071002,China)Abstract: The existing full-text retrieval techniques are mostly targeting the text information.While the retrieval of the scientific documents with mathematical expressions as the main components is still in the exploration stage.In order to make the users can easily use the mathematical formula as the query language to retrieve the scientific and technical documents,a new scientific document retrieval model based on mathematical expression features was proposed.Firstly,the formulas were resolved into the subformulas forming the binary trees,which are used to generate the retrieval feature vectors.In the index phase,the index table with the hierarchical structure was constructed using the extracted document feature vectors.In the retrieval phase,the document vectors were weighted by tf-idf.The similarity between the retrieval vector and the document vector was calculated by using the cosine similarity,and an ordered document retrieval result was obtained.The experiment data was selected from different journals,academic website and public data set of 5 017 science and technology documents which contain 96 362 mathematical formulas.The average retrieval time was 0.428 s,which indicates that the proposed model achieved- 收稿日期:2017-09-18 基金项目:国家自然科学基金资助项目(61375075);河北省教育厅河北省高等学校科学技术研究重点项目(ZD2017208) 第一作者:田学东(1963—),男,天津人,河北大学教授,博士,主要从事模式识别、信息检索的研究. E-mail:xuedong_tian@126.com第6期田学东等:基于数学表达式特征的科技文档检索模型the goal of realizing mathematical expression retrieval with high efficiency.

Regression recommendation algorithm based on extreme learning machine and nearest neighbors

CHEN Aixia,LI Ning

2017, 37(6):  662-666.  DOI: 10.3969/j.issn.1000-1565.2017.06.014

Asbtract ( 501 )   PDF (981KB) ( 448 )  

References | Related Articles | Metrics

This paper proposed a collaborative filtering regression recommendation algorithm based on extreme learning machine(ELM)and nearest neighbors.The algorithm firstly used the k nearest neighbors method to fill the missing attribute value,then the ELM regression machine is used to produce recommendations for the user.On the benchmarking data sets in the field of recommendation,we compared our algorithm with the common recommend algorithm—LRCF algorithm,and verified the effectiveness of the proposed algorithm.

Based on STM32 infrared alarm device and image repair technology

HAO Zhenming,MA Zheng,HAO Jinyuan,ZHANG Youqi,ZHANG Lina

2017, 37(6):  667-672.  DOI: 10.3969/j.issn.1000-1565.2017.06.015

Asbtract ( 522 )   PDF (1814KB) ( 428 )  

References | Related Articles | Metrics

The design of an infrared alarm system based on STM32 single chip microcontroller was introduced.Working principle,hardware composition of system and carried on the detailed narration of image restoration algorithm.After many experiments,proved that the system is simple and practical,safe and reliable,suitable for family security,alert,and many other occasions.In view of the image motion blur problem,the wiener filtering algorithm is used for image restoration,through the experiment testing,confirmed that the algorithm is feasible.