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四川大学学报（自然科学版）

四川大学学报（自然科学版）

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Journal of Sichuan University(Natural Science Edition)
本刊是国内外公开发行的自然科学综合性学术刊物。主要刊登本校理科基础理论和应用研究方面有创造性的学术论文和简报。内容包括：数学、物理学、化学和生物学等基础学科及其分支学科，基础数学论文占有较大比重。读者对象是国内外有关的教学、科学工作者以及研究生和大学生。
  • 发文量：7219
  • 被引量：1070
  • H指数：3
  • 开始收录时间：-
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  • 维普期刊影响因子： 1.01
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  • 国内刊号/CN：51-1595/N
    国际刊号/ISSN：0490-6756
  • 发行周期：双月刊
    邮发代号：62-127
  • 主管单位：国家教育部
    主办单位：四川大学
四川大学学报（自然科学版）-联系信息
  • 主编：王玉忠
  • 电话：028-85412393
  • 邮箱：scdx@scu.edu.cn
  • 地址：四川省成都市武侯区望江路29号
  • 邮编：610064
四川大学学报（自然科学版）-获奖情况
  • • 1995年四川省十佳科技期刊奖
  • • 1995年全国高校优秀学报二等奖
  • • 1999年全国高校优秀期刊二等奖
  • • 2000年四川省第二届优秀期刊一等奖
  • • 2004年全国高校优秀科技期刊二等奖
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四川大学学报（自然科学版） >2022年第1期

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  • 摘要：基于第一性原理密度泛函,开展了氧化钇(Y2 O3)的晶体结构和电子性质的计算研究,对比实验结果验证了计算方法的可行性.通过超元胞模型的密度泛函计算,探究了氧化钇主要本征点缺陷和不同格点阳离子铕(Eu)取代掺杂的形成能.结果表明,富氧条件有利于Eu杂质原子掺入氧化钇晶格,低费米能条件下,Eu原子易于取代周围6个O原子具有中心反演对称性的钇原子;在高费米能条件下,杂质原子对两种格点钇原子取代几率相等.本研究对于提升Eu掺杂氧化钇的发光效率具有一定的指导意义.%The structural and electronic properties of yttria are studied by density functional theory calcu-lations .The results agree well with the experimental ones .Based on the supercell method ,the intrinsic and Eu-doped defects are investigated .Analyzing the formation energies of various defects ,we find that the Eu atom substitutes for the cations more easily under the O-rich condition .The b-site as an inversion center is preferred with the lower Fermi energy ,while the probability of the d-site with lower symmetry is equal to that of b-site .The results are instructive to improve the luminous efficiency .
  • 摘要：In this paper ,we consider numerical methods to solve the fractional advection-dispersion equa-tion with Robin boundary condition .We propose an implicit finite difference scheme based on the shifted Grünwald formula to discretize Riemann-Liouville fractional derivative .Existence and uniqueness of nu-merical solutions are derived .It is proved that the implicit finite difference scheme is unconditionally sta -ble and convergent .Finally ,numerical simulations show that the method is efficient .%本文对带Robin边界条件的分数阶对流-扩散方程进行了数值研究.本文利用移位Grünwald公式对Riemann-Liouville空间分数阶导数进行离散,在此基础上建立一种隐式有限差分格式,并讨论了它差分解的存在唯一性,然后分析了该格式的相容性 、稳定性和收敛性,最后通过数值算例验证格式是可靠和有效的.
  • 摘要：In control theory ,one of the fundamental issues is to design feedback controls ,which is well achieved in the case of linear quadratic control problems .To date ,the study of this problem in the sto-chastic setting is focused much on the natural filtration .In this paper ,we utilize the notion of transposi-tion solution to give a sufficient condition for the existence of an optimal feedback control for the sto -chastic linear quadratic control problems with random coefficients in the general filtration setting ,and we also show that it is also necessary for 1-D system .%控制论中的一个基本问题是为系统设计反馈最优控制.这已在LQ问题中得到了很好的实现.但是,在已有的文献中,对这一问题的随机情形的讨论多集中在自然滤子情形.本文应用转置解这一概念在一般滤子情形下给出了带随机系数的SLQ问题最优反馈控制存在的充分条件,证明了对一维控制问题而言这还是必要条件.
  • 摘要：The part characteristics and the difference of amylase were investigated in tuberous root of sweet potato ,during storage period .The total soluble protein were extracted with 3 mL /g buffer ,it harvests between 2 weeks in the storage time .Difference amylases were found in isozyme composition in tuberous roots of sweet potato during storage period ,by electrophoresis on 8％ native polyacrylamide gel and active stain by using soluble starch as substrate .New amylase responds differently to inhibitors , it is sensitive to EDTA or thiol-group reagent ,and it is more sensitive to temperature than β-amylase . New amylase can be metalloenzyme with disulfide bond .%本文就甘薯收获后,自然储藏期间淀粉酶种类变化和部分性质进行研究.从收获开始,每间隔2周取样1次,按3 mL/g加入缓冲液,提取可溶性总蛋白,经8％ 连续聚丙烯酰胺凝胶电泳(PAGE)及淀粉酶活性染色,结果显示:在贮藏期间,有新的淀粉酶活性带出现,在性质上与原有淀粉酶活性带存在差异.主要表现在,对 β-巯基乙醇和EDTA均非常敏感,而原有淀粉酶活性带不敏感;在热稳定性方面新出现的淀粉酶也更为敏感.说明甘薯块根在贮藏期间,新陈代谢旺盛,有新的淀粉酶表达,是需要二硫键的金属酶.
  • 摘要：提出一种基于稀疏 、稠密特征转换的仿射不变特征匹配算法,其中稀疏特征包括坐标,尺度,仿射模拟参数等,稠密特征指基于图像局部区域内光学属性的局部描述符.本文算法在Affine-SIFT算法基础之上,针对在特征提取阶段仅使用稀疏特征提取的缺陷做出了改进.由于稠密信息只有在稀疏参数满一定足检测条件时才能提取到特征,导致本可以匹配到的特征(包括稀疏 、稠密参数)无法提取,将通过使用稀疏特征构造新的模拟图像,通过将稀疏特征重新稠密化,并在模拟图像基础上进一步提取稀疏特征,同时可检测到原始图像中检测不到的可匹配特征,最终达到增大特征建立匹配的概率,提升正确匹配数量的目标.经实验验证,本文提出的稀密特征转换算法相比于ASIFT算法能大量增加特征匹配的数量.除针对ASIFT方法提供扩展外,该方法也可用于扩展具有充分稀疏特征参数的其它特征提取和匹配方法,并适用于目标识别 、目标分类和三维重建等问题.%In this paper ,an affine invariant feature matching algorithm based on transforming sparse fea-tures into dense features is proposed .In the proposed method ,the sparse features include coordinates , scale ,affine parameters etc .,and the dense features include information of Gaussian kernel ,area de-scriptor .Based on the Affine-SIFT algorithm ,the proposed algorithm improves the shortcomings of sparse feature extraction in the feature extraction phase .Because the dense feature can only be obtained if the sparse parameters satisfy some given conditions ,some good features for matching schemes (inclu-ding sparse and dense parameters ) can not be obtained .In this paper ,the authors construct the new sim-ulation images by using the original sparse features obtained by ASIFT ,and then extract the new sparse features from the simulated images ,and thus the authors can obtain some new features which can not be detected by the original ASIFT method .By using this scheme ,the correct match number in the matc-hing scheme is improved .The effectiveness of the proposed method as beenverified by experiments .Be-sides that it can be applied to extend ASIFT ,the proposed method can also be applied to extend other feature extraction and matching methods with sufficiently parameters of sparse feature ,and be applied to precisely target recognition ,target classification and 3D reconstruction etc .
  • 摘要：Different carbon and nitrogen sources were used to culture the Lentinula edodes Xin808 in this study .The contents of intracellular polysaccharide were determined by phenol-sulfuric acid .The expres-sion level of UDP-glucose pyrophosphorylase ,UGP gene were analyzed by real-time quantitative PCR , and enzyme activity of UGP were also determined .The results showed that ,comparing to the control , besides NH4NO3 treatment group ,the rest of carbon and nitrogen sources could increase the biomass of Letinous edodes ,among which wheat bran exhibited as the best (0 .63g) .The small molecule (sucrose , maltose and mannose) as carbon sources and organic compounds(wheat bran and yellow bean sprouts ) as nitrogen sources ,UGP gene relative expression level obviously were up-regulated ,increased UGP activ-ity ,promoted the biosynthesis of mycelium intracellular polysaccharide .With sucrose as carbon source and wheat bran as nitrogen source ,the relative expression level of UGP gene ,the activity of UGP and mycelium polysaccharide content were the highest .The expression level of UGP gene ,the activity of UGPase and mycelium intracellular polysaccharide of Letinous edodes showed high positive correlation between the three .The small molecule carbon sources (sucrose ,maltose and mannose) and organic ni-trogen sources (wheat bran and yellow bean sprouts) were helpful to the biosynthesis of mycelium poly-saccharide .Sugar and wheat bran could be used as advantage carbon source and nitrogen source under Letinous edodes liquid fermentation .%以香菇新808为材料,利用苯酚-硫酸法和qPCR技术分析不同碳氮源下菌丝体多糖含量及尿苷二磷酸葡萄糖焦磷酸化酶基因相对表达量,并测定其酶活性.结果表明,与对照组相比,除硝酸铵处理外,其余处理均能提高香菇菌丝体生物量,以麦麸处理的生物量最大(0.63g).以小分子糖(蔗糖 、麦芽糖和甘露糖)为碳源 、有机复合物(麦麸和黄豆芽)为氮源时,UG P基因表达量明显上调,酶活性更高,菌丝胞内多糖含量也明显提高.其中蔗糖和麦麸处理下的UG P基因表达量 、酶活性和菌丝胞内多糖含量最高.香菇菌丝UG P基因表达量 、酶活性以及胞内多糖间存在明显的正相关关系.显示小分子碳源(蔗糖 、麦芽糖和甘露糖)、有机氮源(麦麸和黄豆芽)有助于香菇菌丝多糖的合成,其中蔗糖和麦麸可作为香菇液体发酵优势碳源和氮源.
  • 摘要：为探究肾母细胞瘤(Nephroblastoma)发生的关键基因,并筛选出潜在的治疗靶点及生物标志,采用由GEO数据库获取的基因芯片GSE11151和GSE53224,经归一化处理后,通过GO和KEGG分析筛选出差异基因,并通过构建蛋白互作网络获得其中的关键基因.总计获得差异基因404个,其中上调基因385个,下调基因19个.PMCH、CCR5、CCR7、RGS1和KNG1作为关键基因,涉及趋化因子信号通路、G蛋白偶联信号通路,参与肿瘤微环境的形成.这5个关键基因在肾母细胞瘤的发生中有着重要作用,并可能作为潜在治疗靶点及生物标志.%This study was aim to identify gene signatures and potential therapeutic target in nephroblas-toma.Microarrays GSE11151 and GSE53224 were downloaded from GEO database.57 Wilms tumor and 5 normal tissues profiles were screened by GO and KEGG enrichment analysis,and protein-protein interaction(PPI)network of the differentially expressed genes(DEGs)was constructed.In total,404 DEGs were identified,including 385 up-regulated genes and 19 down-regulated genes.The biological processes of GO functional enrichment showed that up-regulated DEGs significantly involved in immune response,immune system process,and leukocyte cell-cell adhesion;while the down-regulated DEGS were related to excretion,metanephros development,and nephron development.In KEGG analysis,the DEGs were enriched in neuroactive ligand-receptor interaction,T cell receptor signaling pathway,and Chemokine signaling pathway.Five genes were identified as hub nodes from the PPI network,including PMCH,CCR5,CCR7,RGS1 and KNG1,which were mostly associated with Chemokine signaling path-way,G-protein coupled signaling pathway,and involved in shaping tumor microenvironment.In conclu-sion,the DEGs,particular hub genes,play significant roles in the development of nephroblastoma and might be the underlying target and diagnostic biomarkers for the treatment of nephroblastoma.
  • 摘要：A novel composite drug nanoparticles(DOX-Cb nanoparticles)have been prepared by repre-cipitation after hydrophobic anticancer drug Doxorubicin(DOX)and hydrophobic anticancer drug chlor-ambucil(Cb)being mixed.1H NM R confirms that DOX and Cb compound is formed via electrostatic force between amino group and carboxyl group.DLS,SEM,AFM and TEM confirm that Composite drug nanoparticles have regular morphology and a narrow size distribution.Cytotoxicity test by using three tumor models(MCF-7,A549,HepG2)shows Composite drug nanoparticles have better effect of killing tumor cells than free DOX,Cb and DOX/Cb mixture.Hoechst staining and western'result by u-sing HepG2suggest that Composite drug nanoparticles kill tumor by inducing tumor cells apoptosis. confocal experiment verifys DOX-Cb nanoparticles are easier endocytosed by tumor cells than DOX.%本文利用两种不同的抗肿瘤药物阿霉素(DOX)和苯丁酸氮芥(Cb)混合,通过再沉淀法制备了一种新型的复合药物纳米粒子.1H NM R证明了DOX和Cb混合后通过氨基和羧基静电力相互作用形成超分子复合物,通过DLS、SEM、AFM、TEM 等表征证明了复合药物纳米粒子具有规整的形貌,较窄的尺寸分布.三种肿瘤细胞模型(MCF-7、A549、HepG2)的细胞毒性实验证明了复合药物纳米粒子相比于单独的DOX、Cb、DOX/Cb混合物有着更好杀死肿瘤细胞的效果.选取HepG2采用Hoechst染色检测凋亡细胞成像以及Western说明了复合药物纳米粒子能更好的诱导了肿瘤细胞的凋亡.共聚焦实验则很好的验证了相比于自由药阿霉素(DOX),复合药物纳米粒子可以更容易被肿瘤细胞内吞.
  • 摘要：CaGd3F11:Eu3+nanocrystals with the morphologies of nanoparticles were prepared by octyl-amine and oleic acid as capping ligands,and anhydrous calcium chloride,rare earth nitrate,n-octanol as the raw materials with solvothermal method.The products were characterized by X-ray diffraction (XRD),transmission electron microscopy(TEM)and fluorescence spectrophotometer.The results in-dicate that CaGd3F11nanocrystals are well-crystallized and their sizes are uniform(about 5 nm).As a lu-minescence host,it shows higher emitting intensity with Eu3+doping.%以无水氯化钙、稀土硝酸盐、正辛醇为原料,以正辛胺和油酸为表面活性剂,通过控制不同的反应条件,采用溶剂热法制备出形貌均匀的CaGd3F11:Eu3+纳米发光材料.用X射线衍射(XRD)、透射电子显微镜(T EM)和荧光分光光度计对合成的纳米晶的粒径、形貌和光学性质进行了表征.结果表明CaGd3F11纳米晶的结晶度良好且尺寸均匀(约5 nm),其作为基质材料,掺杂Eu3+表现出很强的荧光发射.
  • 摘要：基于第一性原理理论求解玻尔兹曼运输方程的迭代解方法准确计算了氟化锂的晶格热导率.采用实空间有限差分超晶胞方法来计算二阶力常数和三阶的力常数.然后通过二阶力常数和三阶原子力常数计算氟化锂晶体的相关物理性质.结果表明,室温下氟化锂的晶格热导率为13.89 W/(m·K),与实验结果一致,这表明这种计算方法可以准确得到这种材料的晶格热导率.%The lattice thermal conductivity of lithium fluoride(LiF)is accurately computed from a first-principles theoretical approach based on an iterative solution of the Boltzmann transport equation.Real-space finite-difference supercell approach is employed to generate the second-and third-order interatomic force constants.Then the related physical quantities of LiF crystal are calculated by the second-and third-order potential interactions at 30 to 1000 K.The calculated lattice thermal conductivity 13.89 W/(m·K)for LiF at room temperature agrees well with the experimental value,demonstrating that the approach can furnish precise descriptions of the lattice thermal conductivity of this material.
  • 摘要：为提高医学图像增强的清晰度和对比度,并提高计算效率,提出一种基于灰度有向无环图(DAG)熵最大化量化分辨率医学图像色调增强算法.首先,采用简单的分段自回归(PA R)模型进行图像目标恢复,并考虑到模数转换的误差利用全最小二乘算法进行PA R模型参数估计,获得高分辨率图像恢复直方图模型;其次,针对可能存在的对比度过低问题,将上述获得的最小二乘算法约束优化问题,建模为DAG中的最大权重路径问题,构建了色调保持最大熵图像增强过程约束优化模型,并通过DAG 图Monge定理特性实现计算复杂度的降低;通过上述两个步骤,实现了医学图像增强过程中图像细节和对比度的同步增强,仿真实验显示所提算法可提供更为有效的医学图像增强效果.%In order to improve the medical image sharpness and contrast,and improve the computational efficien-cy,the authors proposed the gray level DAG maximum entropy based on quantization resolution for Medical im-age tone enhancement.Firstly,the authors used a simple piecewise autoregressive(Piecewise Autoregressive PAR)image target model for recovery,and taked into account the error of analog to digital conversion to use least squares algorithm to estimate PAR model parameter,which obtain high resolution image histogram resto-ration model;Secondly,aiming at the problem of low contrast may exist,the least squares algorithm for con-strained optimization problems was modeled in DAG,which constructed a hue preserving constraint optimization model of maximum entropy image enhancement,and the characteristics of the DAG figure Monge theorem was used to reduce the computational complexity;Through the above two steps,the image details and contrast en-hancement in the process of medical image enhancement are realized.The simulation results show that the pro-posed algorithm can provide more effective medical image enhancement effect.
  • 摘要：In this paper,we determine the forbidden set,introduce an explicit formula for the solutions and discuss the global behavior of a rational difference equation xn+ 1=xnx n-k/αx n+βxn-(k+ 1),w here inter k ∈ N n ∈ N ∪ {0},α,βare real numbers,the initial conditions(x-(k+ 1),x-k,…,x0)∈Rk+ 2.%本文给出方程 xn+ 1=xnx n-k/αx n+βxn-(k+ 1)的奇点集及解的表达式,并讨论了该方程解的全局行为,其中k ∈ N,n ∈ N ∪ {0},α,β都是实数,初始值(x-(k+ 1),x-k,…,x0)∈Rk+2.
  • 摘要：量子相对熵在保迹完全正定的映射作用下是单调递减的.此外,对于一种新提出的Sandw iched Renyi量子相对熵,当映射满足Schw arz不等式或映射保迹正定时,也有研究证明该量子相对熵的单调性也成立.本文利用复插值技巧给出当α∈12,1)时Sandw iched Renyi量子相对熵单调性的另一证明.该技巧曾被用于证明α∈(1,∞)时量子相对熵在保迹正定映射的作用下满足单调性.%It is well known that quantum relative entropy is monotonically decreasing under the complete-ly positive and trace-preserving maps.For a new proposed sandwiched Renyi quantum relative entropy, the monotonicity still holds under the linear trace-preserving map w hose Hilber-Schmidt adjoint map sat-isfies Schwarz inequality.In this paper,we give a new proof for the monotonicity of the sandwiched Re-nyi relative entropy for α∈[12,1).T he proof is based on the complex interpolation techniques,w hich is used to prove the monotonicity under the trace-preserving and positive map for α ∈(1,∞).
  • 摘要：To explore the differences of cadmium resistant ability among rice varieties and the effects of cadmium stress at different levels on their germination and post-germinating grow th,the related phenotypic indices of eighty varieties under low,moderated and high stress levels,respectively,were collected and analyzed by cluste-ring methodology.The results showed that there was a great difference in the ability to resist cadmium in differ-ent rice varieties.The effect of mild cadmium stress on rice germination was more reflected by the single inhibi-tory effect on seed vigor.The comprehensive characters at this level were more consistent with the correlation fitting curve,which was suitable for screening cadmium resistant varieties.The most effects of cadmium stress during rice germination were the green time and root growth.The three hybrid rice parents(maintainer lines Gang 46B,Ⅱ-32B and restorer line Chenghui 3203)belonged to the high resistant type,the three classic indica rice varieties(Guichao 2,Gui Yu 7 and Wushansimiao)were sensitive.%为了探明不同水稻品种间抗镉能力差异及不同镉胁迫水平对水稻种子萌发和出芽生长的影响,对轻、中、重度镉胁迫下8个水稻品种(系)萌发和出芽生长间的相关性状指标进行收集,并通过聚类分析法进行分析评价.结果表明:不同水稻品种抗镉能力存在较大差异.轻度镉胁迫对水稻萌发的影响,更多的体现为对水稻种子活力的单抑制效应,该水平下的综合性状表现更符合相关性拟合曲线,适合用于抗镉品种的筛选.水稻出芽期间受镉胁迫影响最大的是转绿时间和根系生长.三个杂交水稻主要亲本(保持系岗46B、Ⅱ-32B和恢复系成恢3203)都属于高抗型,三个常规籼稻品种(桂朝2号、桂育7号及五山丝苗)都属于敏感型.
  • 摘要：The complex disturbance,weak theoretical basis and lack of methodology are the difficulties of pro-tection program design.With Tianfu International Airport as an example,we try to apply the distributed hydro-logical model(SWAT model)to explore the Ju ren River's ecological hydrology response to airport construction and protection,providing a basis for the planning and evaluation of the project planning and protection meas-ures.The result shows that the R2and NS of model calibration are 0.81 and 0.71 respectively,0.70 and 0.53 in model validation,so the model has good effect on runoff simulation.Combined with the airport projects and ecological compensation planning,we set up"construction damage"and"downstream restoration"scenarios,the result shows that the"construction damage"scenario increases the surface runoff by at least 10%,root infiltra-tion by more than 20%,the actual evaporation value increases,meanwhile the runoff and water production de-crease,so construction damage effect is obvious.The"downstream restoration"scenario reduces surface runoff, water production and river runoff significantly,so the ecological restoration has a certain effect.%本文以天府国际机场为例,尝试引入流域分布式水文模型(SWA T 模型),探索机场建设和保护对举人河流域生态水文的影响,为工程项目保护规划的制定提供依据和评价支撑.模型校准结果显示,率定期的 R2和 NS值分别为0.81、0.71,验证期的 R2和 NS 值分别为0.70、0.53,模型对流域径流模拟效果较好.结合机场建设工程和生态补偿规划,设置了"建设破坏"和"下游修复"情景,结果表明,机场"建设破坏"使流域地表径流至少增加10%、植物根部入渗量减少20% 以上、实际蒸发值增加,河川径流和产水量减少,建设破坏效果明显;流域"下游修复"使地表径流、产水量和河川径流大幅减少,下游治理修复措施是有效的.
  • 摘要：A magnetoresistance(MR)device was proposed by depositing two parallel ferromagnetic stripes on top and bottom of a semiconductor heterostructure.In order to manipulate its performance,we are studied theoretically the changes of transmission,conductance and M R ratio after dope a tunable δ-potential into the device.It is confirmed that an obvious M R effect still exists in the device even though a δ-doping is comprised.Results show that the MR ratio varies intensely with the weight and/or the posi-tion of the δ-doping.T herefore,one can manipulate structurally the M R device by altering the δ-doping, and a tunable M R device can be obtained for magnetic information storage.%通过在半导体异质结上的上下表面沉积两条平行的铁磁条带可获得一个巨磁阻器件.为了更好地调控其性能,我们从理论上研究了在该器件中加入 δ势后,该器件的透射系数、电导和磁阻比率的变化情况.研究发现,加入δ势后,该器件同样具有明显的巨磁阻效应,且其磁阻比率与加入δ势的权重和位置密切相关.因此,我们可以通过改变加入δ势的权重和位置来调控该巨磁阻器件,设计出磁阻比率可调的磁信息存储器.
  • 摘要：鸽群优化算法在求解最优问题时易早熟收敛,陷入局部最优,因此本文提出了带认知因子的交叉鸽群算法.首先,将地图指南针算子和地标算子进行联合交叉运行;然后,在地图和指南针算子中引入了非线性递增的认知因子,并将其视为运动权值的三角函数;最后,在地标算子中,引入呈三角函数递增的压缩因子,增加算法的平滑性.仿真结果表明,改进后的算法收敛精度有很大的提高,能有效地避免早熟收敛,跳出局部极值,具有更好地寻优能力.%In solving optimal problems,pigeon-inspired optimization algorithm(PIO)is easy to prema-ture convergence and trap in local optimum,so this paper presents a cross pigeon-inspired optimization algorithm with cognitive factors.Firstly,map the compass operator and landmark operator no longer run independently,and they are mixed together and operated crosswise;Secondly,in the map and com-pass operator the cognitive factor of nonlinear increment was introduced,and regard as the inertia weight's trigonometric functions;Finally,in the landmark operator,a compressive factor that was in-creasing gradually in the form of trigonometric functions was proposed to make curre smoother.Simula-tion results showed that the improved algorithm's convergence precision had greatly improved,and not only effectively avoid premature convergence,but also jump out of local minima and had better optimiza-tion ability.
  • 摘要：Because of the complexity of the causes of earthquake prediction,it has been recognized an apo-ria by all over the world.In this paper,a new method based on Back-Propagation neural network(BP) and Self-Organizing Feature Map neural network(SOM)is proposed,and applied to the prediction of earthquake magnitude.Firstly,Clustering of the original seismic data by using Self-Organizing Feature Map neural network,which has the inherent law of the samples together,after using BP neural network to the sample data for learning and prediction,the experimental results show that compared with BP neural network prediction results,the increase of SOM clustering process can effectively reduce the pre-diction error.It show s that this method can effectively summarize the factors w hich are closely related to earthquakes and SOM is effective for the classification of the relevant magnitude parameters,and it can be as an effective assistant method to predict the magnitude by using the fuzzy prediction method.%地震预测由于其产生原因的复杂性,一直是世界公认的难题.本文提出一种将多层前馈神经网络(BP网络)和自组织特征映射神经网络(SOM网络)相结合的方法并应用到地震震级的预测中,首先利用自组织特征映射神经网络对地震的原始数据进行聚类预处理,使具有内在规律的样本点集中在一起,之后利用BP神经网络对样本数据进行学习和预测,结果表明,相比直接利用BP神经网络预测结果,增加SOM 聚类处理过程能有效的减小预测误差.说明此方法可以有效的汇总出与地震关系密切的因素,也表明SOM 对相关震级参数分类的有效性,对利用模糊预测方法来实现震级的预测是一种有效的辅助手段.
  • 摘要：In this paper,we investigate the existence of positive solutions for the following fourth-order Sturm-Liouville boundary value problem with p-Laplacian operator:｛(φp(u″(t)))″+q(t)f(t,u(t),u″(t))=0,t∈(0,1), αu(0)-βu′(0)=0,γu(1)+δu′(1)=0,u″(0)=0,u′″(0)=0, w here φp(s)=∣s∣p-2 s,p >1;f:[0,1]×[0,+∞)×R→[0,+∞) is continuous;q(t)> 0,t ∈(0,1).%本文运用迭代法研究了带 p-Laplacian算子的四阶Sturm-Liouville边值问题｛(φp(u″(t)))″+q(t)f(t,u(t),u″(t))=0,t∈(0,1), αu(0)-βu′(0)=0,γu(1)+δu′(1)=0,u″(0)=0,u′″(0)=0正解的存在性,其中φp(s)=∣s∣p-2 s,p >1;f:[0,1]×[0,+∞)×R→[0,+∞]连续;q(t)>0,t ∈(0,1).
  • 摘要：利用Green函数的性质和Schauder不动点定理,本文研究一类带积分边值条件的非线性Caputo型分数阶微分方程边值问题,得到该边值问题正解的存在性定理,推广了相关结果,并举例说明了主要结果的适用性.%We studied the existence of positive solutions for nonlinear Caputo fractional differential equa-tions with integral boundary value conditions.The existence results of positive solutions for the bounda-ry value problems are obtained by applying the properties of Green function and Schauder fixed point theorem,which partly extend the corresponding results of fractional differential equations.Two exam-ples are also presented to illustrate the applications of the main results.
  • 摘要：Porous ceramics with a high open porosity were prepared by employing low-cost kaolin, talcum pow der,and alumina as major raw materials,cement as curing agent,and hydrophobic activated carbon powders as foam stabilizing agent via direct foaming.PdOOH catalyst was loaded on porous ce-ramics via immersion and reaction method.Methylene blue was used as the simulated pollutant in sew-age,and also used as the degradable agent when sodium hypochlorite was decomposed by the palladium-based catalyst.Effects of the loaded amount of catalyst,temperature,and the amount of sodium hypo-chlorite on the degrading speed of methylene blue were investigated.The results indicate that the palla-dium catalyst loaded on porous ceramics can effectively catalyze the decomposition of sodium hypochlo-rite,and significantly improve the color fading speed of methylene blue by oxidation.The time required for color fading drastically decreases with the increment of temperature.It only needs 58 min for methyl-ene blue(10mg/L,50 mL)to fade to colorless w hen the temperature,the amounts of catalyst and sodi-um hypochlorite,and pH value are 40 ℃,0.4 g,5 mL and 7.88,respectively.%本研究以廉价的高岭土、滑石粉、氧化铝为主要原料,水泥为固化剂,疏水型活性碳粉为泡沫稳定剂,采用直接起泡法制备了高开气孔率的多孔陶瓷,采用浸渍和反应法负载氢氧化高钯催化剂.利用次甲基蓝模拟污水,并作为钯基催化剂催化次氯酸钠分解的标识物.研究了催化剂负载量、温度、次氯酸钠用量对催化剂降解次甲基蓝的影响.结果显示,多孔陶瓷负载的钯催化剂能有效催化次氯酸钠分解,极大地提高了次甲基蓝氧化褪色的速率,随温度升高,最终褪色所需时间急剧减少.在温度为40 ℃,催化剂量为0.4 g,NaClO量为5 mL,pH值为7.88的条件下,50 mL浓度为10 mg/L的次甲基蓝仅需要58 min就能褪至无色.
  • 摘要：We investigate theoretically the nonclassical properties,such as cross correlation function and sub-Poissonian distribution effect,for the nonlocal coherent photon-added two-mode circular state.The results show the superposition number and excitation number have significant effect on these properties. When the superposition number N = 2,the value of cross correlation function decreases monotonously with the increasing of the average photon number of single-mode and the nonlocal coherent photon-added two-mode circular state has the cross correlation effect.Increasing the superposition number,the cross correlation effect will be reduced.When the superposition number N = 2,sub-Poissonian distribution effect of the nonlocal coherent two-mode photon-added circular state can be observed only when single-mode average photon number is greater than a certain threshold value.%理论上研究了联合增光子二模圆态的互相关函数,亚泊松分布等非经典特性.数值计算表明激发数和叠加态数对这些特性有明显的影响.当叠加态数 N = 2时,交叉关联函数随单模平均光子数的增大而单调减小,并且联合增光子二模圆态存在关联效应.随着叠加态数的增加,二模光场间的关联效应将减弱.当叠加数 N = 2时,只有当激发数 s ≤ 2时,且单模平均光子数大于某阈值时,联合增光子二模圆态才存在亚泊松分布效应.
  • 摘要：Hydrogen sulfide(H2S)is the endogenous signaling molecule and has attracted great attention for its significant role in curing cardiovascular nervous system diseases.Firstly,we surveyed the effect of SCH9 gene deletion on H2S production in SCH9 deletion yeast strains RCD398,RCD399 and TS120-2d by quantifying H2S levels using lead acetate paper.WT(BY4741)yeasts produced H2S of 4(mm)/A600nmafter cultured for 48 h.While Sch9Δ(RCD398)only produced H2S of 0.4 mm /A600nmwithout caloric restriction.Under caloric restriction,WT(BY4742)yeasts produced H2S of 10(mm)/A600nm after cultured for 48 h,whereas H2S was not detected in Sch9Δ(RCD399)yeasts.Secondly,we studied the effect of SC H9 gene deletion on exogenous H2S degradation by substitute GYY4137 and NaHS as external H2S donors.H2S wasn't detected in WT(BY4742)strain after cultured for 72 h,while re-mained to be detected in Sch9Δ(RCD399)strain.These results suggest that SCH9 deletion decreases synthesis and catabolism of H2S in yeast.%H2S作为胞内气体信号分子,在心血管和神经系统方面的治疗显著效果引起了人们的关注.首先,为了探究酿酒酵母中 SC H9基因缺失对其 H2S生成的影响,我们以酿酒酵母 SCH9基因缺失型菌株RCD398、RCD399和TS120-2d为研究对象,用醋酸铅试纸检测反应体系中H2S含量.非热量限制条件,WT(BY4741)培养48 h 产生了4(mm)/A600nm H2S,而 Sch9Δ (RCD398)只产生0.4(mm)/A600nm.热量限制条件下,WT(BY4742)培养48 h产生了10 (mm)/A600nm的H2S,而 Sch9Δ(RCD399)未检测到H2S.其次,为了探究SCH9基因缺失菌株对外源H2S分解的影响.用GYY4137和NaHS作为H2S的供体.WT(BY4742)培养72 h之后未检测到H2S,而Sch9Δ(RCD399)仍可持续检测到大量H2S.结果表明 SCH9缺失既可以下调酿酒酵母中H2S的生成,也可以下调酿酒酵母对外源H2S的分解.
  • 摘要：The model of porous particles is built in this paper,and the optical properties of them were carried out utilizing discrete dipole approximation and Bruggeman effective medium theory for the num-ber of air pockets from 49 to 299.After analyzing and comparing the scattering properties of porous par-ticles obtained by two computing methods,we found that the effective medium theory has a good validi-ty for the extinction efficiency,the absorption efficiency and the scattering efficiency when the number of air pockets less than a certain value,but not vice versa.While for the single-scattering albedo and the asymmetric factor,the effective medium theory always keeps a good validity in the research scope of this paper.The results also revealed that the inference of the doctor Michael about the validity of effective medium theory in light scattering of porous particles was not comprehensive.%采用离散偶极近似法和Bruggeman有效介质理论分别计算了气泡个数为49、99、149、199、249和299的含气泡粒子的辐射特性参数.比较分析后发现:对于衰减因子、吸收因子和散射因子,在气泡数目小于一定值时,有效介质理论具有较好的适用性,反之适用性较差;对于单次散射反照率和非对称因子,有效介质理论均具有较好的适用性.同时证明了M ichael教授关于有效介质理论对含气泡粒子适用性推测的片面性.
  • 摘要：License plate detection is an important part of the license plate recognition system,w hich deeply affects the accuracy of license plate recognition.A method for cascade adaboost license plate de-tection based on HSV color model and multi-block local binary patterns(MB_LBP)is presented to real-ize fast and accurate license plate detection and recognition.Firstly,the license plate image is trans-formed from RGB color space to HSV color space,and the ratio of the blue pixels to the total pixels of the license plate is counted to construct the first class strong classifier.Then,the MB_LBP feature is extracted from the license plate character samples,and the feature selection and the classifier training are carried out by using the Adaboost classifier training method.Finally,a new license plate detection algo-rithm is formed by using the Cascade structure detection method.Experiments results show that the li-cense plate detector improves the detection rate and the detection speed.%车牌检测作为车牌识别系统中的重要环节,直接影响着车牌识别的准确度.为提高车牌的检测率和检测速度,提出了一种基于 HSV 颜色模型和多分块局部二值模式(MB_LBP)特征的级联Adaboost车牌检测方法.首先将车牌图像由RGB颜色空间转换到 HSV 颜色空间,统计蓝色像素占车牌总像素的比例,来构建第一层强分类器;其次对车牌字符样本提取MB_LBP特征,利用Adaboost分类器训练方法进行特征选择及分类器训练,最后利用Cas-cade结构检测法形成一种新的车牌检测算法.实验表明,本文算法有效的提高了车牌检测率和检测速度.
  • 摘要：F特征函数是描述分抗逼近电路集总特征值的新概念.为全面定量分析与表征分抗逼近电路的F特征逼近性能,在F特征函数基础上,提出F特征逼近性能分析的相对误差、精度、带宽、带宽指数、K线斜率图、F指标和逼近效益等一系列概念及相应的数学函数.并将其应用到Oldham分形链分抗逼近电路的F特征逼近性能分析,以证明其有效性.%F-frequency characteristics function is a new concept about lumped characteristics quantity of the frac-tance approximation circuit.In order to quantitatively describe the approximation performance of F-frequency characteristic of the fractance approximation circuit,a series of concepts and corresponding mathematical func-tions about approximation performance analyses of F-frequency characteristic are proposed in this paper based on F-frequency characteristic function,including relative error,approximation accuracy,approximation bandwidth, approximation bandwidth exponent,K-diagram,F-index,approximation benefit,etc.And these concepts are used to analyze the Oldham fractal fractance approximation circuit to verify its effectiveness.
  • 摘要：本文利用鞍点定理得到了二阶哈密尔顿系统｛ü(t)+ ▽ F(t,u(t))= 0,(A)t ∈ R, u(0)-u(T)= (u)(0)-(u)(T)= 0,T > 0在带有混合条件时的周期解的存在x性,推广了已有结果.%In this paper,existence of periodic solutions of the following nonautonomous second order Hamiltonian system with mixed condition ｛ü(t)+ ▽ F(t,u(t))= 0,(A)t ∈ R, u(0)-u(T)= (u)(0)-(u)(T)= 0,T > 0 is obtained by using the saddle point theorem.Our results extend some known results.
  • 摘要：The K(a)hler angle of a surface immersed in an almost Hermitian manifold is an important invar-iant which can be used to measure the deviation of the surface from being a complex(or pseudo-holomor-phic)one and,in particular,the surface with a constant K(a)hler angle has been an interesting object in the study of submanifolds for years.In this paper,we prove two rigidity theorems for complete self-shrinkers of mean curvature flow with constant K(a)hler angle,which are immersed in the complex Eu-clidean space C3of dimension 3.These are direct extensions of some known theorems for self-shrinkers immersed in C2%浸入到近复Hermit流形的曲面的K(a)hler角是一个重要的不变量,可以用于刻画曲面偏离拟全纯曲线的程度.近年来,具有常K(a)hler角的曲面仍是很有意义的研究对象.对于3维复欧氏空间C3中具有常K(a)hler角的曲面收缩子,本文证明了两个刚性定理.这些定理是有关C3中曲面自收缩子的相应定理的直接拓展.
  • 摘要：The Tb3+-TiO2photocatalyst with different amounts of doped Tb3+and under different calci-nation temperatures were synthesized by sol-gel method,and characterized by XRD and FT-IR and pho-tocatalytic activity.Malachite green experiment was chosen to evaluate photocatalyst's activity.The re-sults showed that the obtained powder is anatase TiO2,and with the Tb3+doped,which indicating that Tb3+doped rare earth can refine the grain.The photocatalytic material experiments of malachite green degraded showed that,calcined at 400 ℃,Tb3+-TiO2molar ratio of 2.5% catalyst,irradiated without lighting 3 h,the degradation rate could be 81.1%.%以Tb3+掺杂纳米TiO2为研究内容,采用溶胶-凝胶法合成不同Tb3+掺杂量、不同煅烧温度的Tb3 +-TiO2光催化剂.利用X射线粉末衍射(XRD)、红外(FT=IR)等现代分析技术对Tb3+掺杂TiO2纳米晶样品的结构进行测试、表征.以孔雀石绿溶液为目标降解物,研究了稀土Tb3+掺杂量和煅烧温度对其光催化活性的影响.实验结果表明:Tb3+掺杂纳米TiO2能够细化晶粒,提高热稳定性;Tb3+掺杂提高了TiO2光催化活性.当煅烧温度为400 ℃时,Tb3+-TiO2=2.50% 的催化剂,在自然光照射下,降解孔雀石绿溶液3 h,降解率可达81.1%.
  • 摘要：本文提出一种利用He+离子链模型来增强谐波辐射强度的方案.通过求解薛定谔方程,理论模拟了单个He+离子以及He+离子链辐射谐波的特点,并结合电离几率,谐波辐射时频分析图,含时电子波包运动分析了谐波辐射及电子运动过程.计算结果表明,使用He+离子链模型可以有效增强谐波强度以及延伸谐波截止能量.%In the present paper,we propose an effective method to enhance the intensity of the harmonic spectrum by using the He+ion chain model.Through solving the time-dependent Schr(o)dinger equation, the harmonic spectra from the single He+ion and the He+ion chain have been theoretically calculated. Moreover,the ionization probabilities,the time-frequency analyses of the harmonic spectra and the time dependent wave functions have been used to explain the harmonic emission process and the electron mo-tion.Results show that the harmonic intensity can be remarkably enhanced and the harmonic cutoff can be extended by using the He+ion chain model.

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