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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）

北大核心

CSCD

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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：5743
  • 被引量：1070
  • H指数：3
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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） >2021年第006期

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  • 摘要：为了安全便捷地获取严重急性呼吸系统综合征冠状病毒(Severe Acute Respiratory Syndrome coronavirus,SARS coronavirus)的RdRp基因,作者合成了26条寡聚核苷酸片段,利用组装PCR(assembly PCR)在体外构建了SARS病毒的RdRp基因片段,并建立了基于Vero E6细胞的SARS RdRp基因的稳定表达株.之后设计了4对针对SARS RdRp基因的siRNA,基因干扰表明这4对siRNA均能高效干扰SARS RdRp基因在Vero E6细胞中的表达.至此,本文提供了一种安全便捷地获取病毒基因的方法.
  • 摘要：作者首先利用强拟开集的概念引入了正则强拟开(闭)集、强拟S-闭空间等概念,然后讨论了强拟S-闭空间的特征以及强拟S-闭空间的强拟正则化,最后指出强拟S-闭性是半拓扑性质.
  • 摘要：三维CAD检索技术对产品设计、重用具有促进作用.经典的三维模型检索算法——形状分布算法SD,适用于全局特征相似的模型检索,但对于全局相似但局部差异明显的模型则无法有效检索.针对这一问题,本文首先提取SD特征,并利用基于法线夹角与面积分布的特征提取技术来对模型局部特征进行描述,随后通过构造特征矩阵来融合提取到的法线夹角与面积分布两类特征,最后将SD特征与法线夹角与面积分布特征进行组合,形成新的特征并应用于检索.实验结果验证了该方法的有效性.
  • 摘要：针对基于H.264/AVC帧内预测模式的信息隐藏算法,本文提出了一种信息隐藏检测方案.由图像残差DCT系数量化后的重建信号与原始信号差的期望为零,理论分析得到对于利用H.264/AVC帧内预测模式嵌入秘密信息的视频,经过H.264/AVC重压缩后,其载密的非最优帧内预测模式将转变为嵌入秘密信息前自然视频的最优预测模式.基于此推论及其实验结果,本文构造了帧内预测模式转移概率矩阵,并以此为特征结合支持向量机分类器进行视频信息隐藏检测.实验表明,本文算法对于不同类型的低嵌入率载密视频都具有很高的正确检测率.
  • 摘要：本文对动态量子点驱动的通过三个量子点接触的电子输运的静电调制效应进行了研究.通过对栅极施加不同电压形成不同的量子点接触静电势,从而改变动态量子点的形状.随着栅极电压的改变,电子库中的费米能也会随之改变,同时,影响下一个量子点接触的静电势垒的梯度.实验证明,量子点接触的电势并不总是阻碍电子输运.电势的调制能够帮助我们了解电子与电子之间的库伦阻塞效应.
  • 摘要：本文以恒界面池法研究了HNO3介质中TiAP对Th(Ⅳ)的萃取动力学性质.在一定条件下,考察了萃取时间对萃取率的影响,并测定了搅拌速度、温度、界面积以及各反应物初始浓度对萃取速率的影响.实验结果表明:萃取体系在约6h后达到平衡;搅拌速度(120-180rpm)对萃取速率无显著影响,萃取反应的活化能为23.20 kJ/mol,萃取过程为界面反应的混合控制模型.在HNO3介质中,TiAP萃取Th(Ⅳ)的化学反应速率方程为:r=-dcTh(NO3)4/dt=k[Th(NOa)4].05[TiAP]1.77[HNO3]0.38,其中,k=1.6×10-2 (mol/L)-2.2·s-1.
  • 摘要：本文应用生物信息学和RT-PCR方法分别获得了三角褐指藻两个PEPC全长cDNA,分别称为:PtPEPC1和PtPEPC2,前者完整开放阅读框3030bp,编码1009个氨基酸,后者完整开放阅读框2634bp,编码877个氨基酸;基于克隆所得PtPEPC的ORF构建了反向互补RNA干扰载体pPha-PtPEPC1RNAi和pPha-PtPEPC2RNAi,并用轰击法(PDS-1000/He)转化野生型三角褐指藻,筛选鉴定到了所需的阳性转基因藻;实时定量RT-PCR结果揭示:含PtPEPC RNA干扰结构的转基因藻的PEPCase基因的表达水平比野生型三角褐指藻该酶的表达水平有显著降低;野生型藻和转基因藻的油脂含量定量分析结果揭示:含RNAi干扰结构的转基因三角褐指藻油脂含量也明显高于野生型三角褐指藻,油脂增幅达2％～12％.
  • 摘要：从麻疯树基因组中克隆到一个CBF2基因(命名为JcCBF2).运用生物信息学的分析手段对该基因序列及其编码的蛋白质序列进行了分析,结果表明JcCBF2蛋白中不止包含保守的AP2/EREBP结合结构域,还具有CBF转录因子特征序列PKK/RPAGRxKFx-ETRHP、DSAWR.实时荧光定量PCR结果显示,JcCBF2基因主要在麻疯树叶片内转录表达,对低温胁迫极其敏感,但对干旱及盐胁迫不敏感,初步研究表明JcCBF2基因是低温诱导型转录因子.
  • 摘要：本文对于稳态自然对流问题建立了一种内罚有限元格式.该方法通过在通常的混合Galerkin形式中添加能够对速度、压力和温度的梯度跳跃加以L2-控制的稳定项有效地解决了对流占优和速度、压力混合元空间因要求满足LBB条件而造成的解的不稳定性.最后,本文得到了速度、压力、温度的最优先验误差估计.
  • 摘要：本文研究了具有涨落阻尼的线性过阻尼分数阶振子的共振现象.利用分数阶Shapiro-Loginov公式和Laplace变换,本文得到了系统响应的一阶稳态矩的解析表达式.对稳态响应的振幅增益的分析表明该系统存在三种不同形式的共振现象:bona fide共振、随机共振和广义随机共振,而分数阶的变化将导致bona fide共振的多样化.
  • 摘要：针对在Hadoop分布式文件系统中,系统默认的数据负载均衡算法在做负载均衡决策时只根据磁盘空间使用率这单一的衡量指标无法准确反映集群中各服务器实际的工作负载状况这一缺陷,通过研究和分析Hadoop分布式文件系统本身的负载均衡机制和在其基础上改进的负载均衡算法,本文提出了一种基于多衡量指标的负载均衡方法,定义了一个衡量指标函数,然后根据该函数计算集群中各数据服务器的负载量来对集群进行负载决策.最后通过实验结果表明,该方法有效地提高了Hadoop分布式文件系统中的负载均衡效果.
  • 摘要：在domain理论中,事件结构和信息系统是domain的逻辑表示的主要工具.通过研究事件结构和它所对应的domain结构之间的关系,作者提出了L-稳定事件结构以及L-映射的概念,证明了L-稳定事件结构和L-映射构成的范畴等价于具有性质I的代数L-domain和稳定映射构成的范畴,由此说明了可以通过特殊的事件结构来表示具有性质I的代数L-domain.%In domain theory, event structure and information system are the main tools of the domain logical representation. According to studying the relation between event structure and the corresponding domain structure, the authors define the L-stable event structures and L-mappings between them and show that the category whose objects are L -stable event structures and morphisms are L -mappings is equivalent to the category (object: algebraic L-domain satisfying property I, morphism: stable mapping). So the special event structure can represent algebraic L -domain satisfying property I.
  • 摘要：针对传统的PI(Proportional Integral)算法收敛速度慢等问题,基于瞬时到达速率提出了一种新的PI主动队列管理算法PICA(Proportional Integral Based on Cellular Automaton).首先,该算法结合瞬时队长和瞬时到达速率建立了丢包策略,并利用元胞自动机刻画了数据包的动态特性.同时,通过仿真实验,将该算法与传统的PI算法以及RPI (Rate based Proportional and Integral)算法进行比较,结果发现PICA算法在有效传输数据包、时延和丢包率等方面的性能都较优.%In order to mitigate the slow of convergence rate in traditional Proportional Integral algorithm, a novel active queue management algorithm (Proportional Integral Based on Cellular Automaton, PICA) is proposed based on instantaneous arrival rate. At first, combined with instantaneous queue length and instantaneous arrival rate, the dropping strategy is presented in this algorithm, and the dynamic characteristic of packet is depicted by cellular automaton. Then, a simulation was conducted to study on the algorithm performance between PICA and PI, as well as RPKRate based Proportional and Integral). The result shows that it is better performance in efficient transmission packets, delay and dropping rate for PICA algorithm.
  • 摘要：Game map generation is one of the hot spots of procedural content generation (PCG). In this article, the map of MegaGlest which is a open source RTS game is the object of study. Fairness, play-ability, strategy and interesting are regarded as the optimization goals. Multiobjective Particle Swarm Optimization (MOPSO) is presented for game map generation. The results of experiment show that the maps generated have clear improvements in four optimization goals, and can improve the gaming experience of players.%游戏地图自动生成是目前过程内容生成PCG(Procedural Content Generation)研究的热点之一,本文以开源RTS游戏MegaGlest的地图为研究对象,以公平性、可玩性、战略性和趣味性为优化目标,提出多目标粒子群优化的游戏地图生成算法.实验结果表明,自动生成的地图在4个优化目标方面具有明显改进,能给玩家提供更好的游戏体验.
  • 摘要：采用量子化学方法研究了N,N'-1,3-苯基二-(7-二乙氨基-3-甲酰胺)香豆素分子的几何结构、电子结构及热力学性质.结果显示,该分子的反式构型三个环几乎位于同一平面,能量最低结构最稳定.气相中最低能量跃迁吸收峰出现在428 nm,溶剂作用使其蓝移约20 nm.在298.15 K标准大气压下,标题化合物分子的标准摩尔生成焓和标准摩尔生成自由能分别为4729.63和5561.27kJmol-1.%The geometric structures, electronic structure, and thermodynamic properties of N,N'-(1,3-Phenylene)bis(7-(diethylamino)-coumarin-3-carboxamide) coumarin molecule were studied by quantum chemistry theory. The results show that the molecule's energy is lowest and structure is the most stable when three rings of this molecule are almost in the same plane. In gas, absorption wavelength of the lowest energy excitation was obtained at 428 nm, solvents made it blue-shifted about 20 nm. At 298. 15 k, the standard molar formed enthalpy and free energy of the title compound molecule were 4729. 63 kJ mol-1 and 5561. 27 kJ mol-1 respectively.
  • 摘要：In the pH 7. 8 BR buffer system, the saffranine and the sodium dodecyl sulfate function, forms the ionic association, the solution color has the change. Its most greatly colored wave length located at 510nm place, in the colored wave length place, the lauryl sodium sulfate's density and the solution coloration assumes the good linear relationship, it may be used in the determination of sodium dodecyl sulfate. The wave length is 510nm place, the sodium dodecyl sulfate's density is 0. 5~5. 0 μg · mL-1 scope observes the Bill law, the correlation coefficient respectively is R=0. 9992, molar absorption absorptivity for 7. 4×104 L · mol-1 · cm-1, the detection limit is: 0. 059 μg · mL-1. This method fast, keen, the operation is simple, it be used in the determination of sodium dodecyl sulfate in the environmental water samples, the result is satisfied.%在pH7.8的BR缓冲体系中,番红花红T与十二烷基硫酸钠作用,形成离子缔合物,溶液颜色发生改变.其最大显色波长位于510 nm处,在显色波长处,十二烷基硫酸钠的浓度与溶液的显色呈良好的线性关系,可用于十二烷基硫酸钠的测定.在波长为510 nm处,十二烷基硫酸钠的浓度为0.5～5.0 μg·mL-1范围内遵守比尔定律,相关系数分别为R=0.9992,摩尔吸光系数为7.4×104 L·mol-1·cm-1,检出限为:0.059 μg·mL-1.该方法快速、灵敏、操作简便,用于环境水样中十二烷基硫酸钠的测定,结果满意.
  • 摘要：The paper has built partition function model by product approximation, then taken the normal temperature calculated of moment square R2v > which without rotational transition, as a constant value, and applied to high temperature. On the basis of programming compiler and computing the spectral line intensities and absorption coefficients of 001-000 band for hydride BH2 free radical molecule at several temperatures. The results show that calculated values of total internal partition sums are consistent with the datum obtained from Gauss calculations and the fitted values by five factorial polynomials. Such excellent agreements lend us much credibility in the calculations of spectral intensities and absorption coefficients at different temperatures. From the spectral figs at different temperatures, we find that they are accorded with the spectrum characteristic of asymmetric top molecules in some literatures. These results are of significance for measuring high-temperature spectrum by experimental calculation of radical molecules.%利用乘积近似法构建配分函数模型,再将常温下的无转动跃迁矩平方近似为一常数并应用于高温,进一步编制程序,计算了氢化物BH2自由基分子配分函数和001-000跃迁带不同温度下的谱线强度和吸收系数.结果表明计算的配分函数值与高斯计算和五阶多项式拟合值,不管是在常温还是高温下,都符合较好,这说明构建的模型是可靠的,可以用来进一步研究谱线强度和吸收系数；从获得不同温度段的模拟光谱强度图也可以看出,本文计算结果与文献中的非对称陀螺分子谱带形状基本一致.这对进一步从实验上测量自由基分子高温光谱具有一定的参考作用.
  • 摘要：The phase-separated binary self-assembled monolayer was prepared by the 4-aminothiophenol depositing in a pentanethiol self-assembled monolayer templete, which was fabricated by incubating the unsaturated self-assembled monolayer in liquid by the molecular kinetics and thermodynamics properties in the self-assembled progress. It is a general method to prepare phase-separated binary self-assembled monolayer. We found that the area of the 4-aminothiophenol domain decrease with the increase of the pentanethiol absorption time on gold surface, the incubating progress and the incubating temperature are important to the quality of phase-separated binary self-assembled monolayer.%利用分子自组装热力学及动力学特性,通过控制第一种分子的组装饱和度,以及中间有序化处理过程,得到混合自组装模板,成功的组装出具有相分离结构的五碳硫醇和巯基苯胺二元分子混合自组装膜.这种混合自组装方法对二元相分离结构的混合自组装分子膜具有一定的普适性.同时发现,在两步法混合自组装膜中,随着第一种分子的沉积时间增长,第二种分子的组装面积减小.另外对第一种分子膜进行有序化处理以及不同的处理温度对二元混合自组装膜的质量和结构有着较大的影响.
  • 摘要：The single-strain, multi-strain composite solid-state fermentation was used for the gossypol-degrading screening. A beer yeast (Saccharomyces cerevisiae) with high efficiency of gossypol-degrading was screened. By single-factor test to determine the initial fermentation medium mushroom detoxification process conditions, the best conditions for a single factor as follows: inoculums level 15% , moisture content 60%, fermentation temperature 40 °C. Response surface analysis disclosed that the factors' interaction between each other is not significant, one factor's effect to detoxification of gossypol wouldn' t be affected significantly if any other factor changed, and the optimal fermentation conditions of gossypol from golden mushroom medium as follows: inoculums level 14. 85% , moisture content 60. 70% , fermentation temperature 40. 15 °C, the content of gossypol reduced from 287. 563 mg/kg to 33. 685 mg/ kg, and the detoxification efficiency was up to 88. 286%.%通过单菌种,多菌种的复合固态发酵筛选,建立了一种高效降解金针菇栽培袋料中棉酚的方法:以酿酒酵母(Saccharom yces cerevisiae)单菌种发酵.通过单因素试验初步确定金针菇栽培袋料发酵脱毒的工艺条件,单因素最佳条件为:接种量15％,含水量60％,培养温度40℃.通过响应面法优化脱毒条件,响应面分析结果为三个因素两两之间的交互影响作用并不显著,一个因素对棉酚脱毒率的影响不会随着另一因素的改变而有明显变化,并得出金针菇栽培袋料发酵脱毒的最优条件为接种量14.85％,含水量60.70％,培养温度40.15℃,金针菇栽培袋料中的棉酚从287.563 mg/kg降至33.685 mg/kg,脱毒率达到88.286％.
  • 摘要：利用Galerkin方法和Leray-Schauder不动点定理,一类复Gross-Pitaevskii方程的初边值问题的H2解的唯一存在性得到了证明.%The unique existence of H2 solutions to the initial-boundary value problem for a class of complex Gross-Pitaevskii equations (GPEs) is proved by using the Galerkin method and Leray-Schauder fixed point theorem.
  • 摘要：In 1946,Erd（o）s and Niven proved that there are at most finitely many positive integers n for which one or more of the elementary symmetric functions of 1,1/2,…,1 are integers.In this paper,we show that if n ≥ 2,then none of the elementary symmetric functions of 1,1/4,…,1/(3n-2) is an integer.%在1946年,Erd(o)s和Niven证明只有有限多个正整数n,使得1,1/2,…,1的一个或多个初等对称函数是整数.在本文中,我们研究算术级数(1+3i)∞i=0.我们证明当n≥2时,1,1/4,…,1/(3n-2)的所有初等对称函数都不是整数.
  • 摘要：大型分布式系统通常将系统内存储的数据复制到多个节点以减少数据访问的时间开销.然而,随着数据副本数量的增加,副本数据更新过程的写代价也随之增加.如何合理地选择数据副本的存储节点、控制副本数量,以平衡数据的读写开销,进而有效地降低系统总的数据访问代价是分布式存储的研究热点.针对这一问题,本文提出了一种基于遗传算法的数据复制方法来平衡数据的读写开销.具体地本文对遗传算法进行了以下两方面改进:(1)建立了一个综合考虑读写数据传输代价的评价函数,以控制遗传算法的收敛方向,搜索数据副本存放位置的最优或次优策略；(2)通过时间序列预测方法来启发式地指导染色体变异操作,以合理控制副本数量适应数据的读写访问趋势.实验表明,与传统方法相比,本方法能够更有效地降低数据访问的总时间代价.%Big distributed systems usually reduce data access time by replicating data to many servers. However, update overhead increases with replica number increases. The hot topic of distributed storage is how to choose replicas' placement and control replica number to balance read and update cost, thus reducing the access overhead of distributed system. To solve this problem, this article proposes a data replication strategy based on the Genetic Algorithm to balance read and update overhead. Specifically, this article improves Genetic Algorithm in the two following aspects: 1. building an evaluation function by considering read and update overhead to control the convergence direction of the Genetic Algorithm for finding the best or the suboptimal replica placement. 2. directing chromosomal mutation heuristically by time series forecasting method to control replica number to adapt to the trend of reading and updating data. Experiment results show that this method can efficiently reduce the whole time overhead of accessing data.
  • 摘要：PCR specific primers were designed based on sequences published on Genbank. A triple-PCR was developed based on conventional PCR and reaction parameter we optimized to develop a detection method. To characterize the accuracy of this method, conventional PCR and triple-PCR were used to test same samples. Results indicated that the coincidence rate of these two methods were 100%. Triple-PCR and disk diffusion method were both performed to detect the genotype and phenotype of 412 bacterial isolated from swine and chicken. The result showed that bacterial resistance rate to tetracycline was 95%, to doxycycline was 92%, and to minocycline was 84%. The detection rate of tetA, tetC and tetM were 47. 57% , 38. 35% , 34. 95% , respectively. The coincidence rate of two methods was 88% , which suggested high consistency.%针对GenBank上已公开的四环素类耐药基因tetA、tetC、tetM序列进行比对分析,设计特异性扩增引物,建立三重PCR法快速检测方法.结果表明,单重PCR和三重PCR的符合率为100％.应用本检测方法和传统药敏试验方法(药敏纸片法)对412猪、鸡源细菌的四环素耐药基因和表型同时进行检测.PCR检测实验结果显示,在412株待检细菌中,tetA、tetC、tetM的检出率分别为47.57％,38.35％和34.95％.药敏实验结果表明,待测细菌对四环素的耐药率最高,为95％；对多西环素的耐药率次之,为92％；对米诺环素耐药率相对最低,为84％.比较两种方法,发现其检出结果的符合率为88％.说明两种方法具有较高的一致性.本研究建立了一种猪、鸡源细菌四环素类药物耐药基因三重PCR检测方法,并进行了初步应用.
  • 摘要：在实际监控场景中,运动阴影的存在将对目标检测的准确性产生直接影响.针对此问题,本文提出了一种采用三层码书模型以此来提高阴影检测识别率的算法.该算法首先通过传统码书模型获取前景,然后对前景部分建立备选码书模型,再从备选码书中提取出具备阴影特质的点,构建阴影码书模型,最后通过该模型去除运动阴影.实验结果表明,与传统算法相比,该算法对阴影检测识别率有较大的提高.同时,通过对不同场景的对比,结果说明该算法具备良好的鲁棒性.%In actual surveillance scenes, shadows severely affect the accuracy of moving objects detection. In this paper, a three-layer codebook model is proposed to improve the shadow discrimination rate. Firstly, the foreground points are obtained by the traditional codebook model. Secondly, a cache model is constructed and then the foreground points which meet the characteristics of shadow are selected to form a codebook shadow model. At last, the moving cast shadows are removed through the codebook shadow model. Experimental results illustrate that our method has a superior performance than the conventional shadow detection algorithm. The results obtained with scenes of different types and of different conditions show the robustness of the approach.
  • 摘要：由于显微场景照度动态范围较大,普通显微成像设备拍摄的单幅图像无法真实表现实际场景,提出了一种基于HSV空间的高动态范围图像合成方法.首先,将同一场景不同曝光度的序列图像从RGB空间转换到HSV空间.其次,利用Debevec-Malik方法将图像序列的亮度分量合成为高动态范围的亮度图像,再对其进行色调映射得到最终的亮度分量.另外,我们对色调和饱和度分量分别进行加权平均合成,从而得到最终图像的色调与饱和度分量.实验结果表明,本方法对彩色显微图像具有较好的处理效果.%Single image can not well represent the real scene, because microscopic scene illumination is always high dynamic, this paper proposed a method of the composition of high dynamic image based on HSV space. First, the authors convert image sequences of different exposures of the same scene from RGB space to HSV space, process luminance component using Debevec-Malik method and compress the high range luminance component with tone mapping. Otherwise, the authors separately deal with hue and saturation component, using weighted-average method to get the final hue and saturation. The experimental result shows that the proposed method can get good composition result.
  • 摘要：针对Windows下MDSL(多通道同步数字记录仪)系统耦合度高,稳定性和实时性不够理想的缺陷,本文提出了新的系统架构和设计.该设计基于Linux操作系统(2.6内核),采用了多进程方式降低系统耦合度,提高系统可靠性,并采用双机冗余和守护进程等设计保证系统稳定性,同时采用了多线程管理方式实现远程控制单元.实践表明,新系统拥有更好的可靠性以及可维护性.%Since Windows based MDSL system has defects like high coupling, relatively not stable and weak real-time, this paper puts forward a new system structure and design. Based on the Linux operating system (2. 6 kernel) ,this design uses a multiprocessing mode to reduce the system coupling, improve the system reliability, and ensure the stability of the system by using designs like dual machine redundancy and daemon process, and using the multi-threaded mode to process command so as to realize the remote control unit. The practice shows that the new system has better reliability and maintainability than the old one.
  • 摘要：Sodium salts of Omeprazole, Lansoprazole, Pantoprazole, Rabeprazole and Uaprazole are proton pump inhibitors (PPIs) containing the chiral sulfoxide, so each has a pair of enantiomers. In order to understand the electronic structures of above five PPIs, the density functional theory (DFT) and the polarizable continuum model (PCM) were performed on the S isomers in water at B3LYP/6-311 + +G** level. On this basis, the ECD spectra of these molecules were studied using the time-dependent density functional theory (TD-DFT) at the same level. The calculation results demonstrate two conclusions: (1) In the S isomers of above five PPIs, the bond critical points indicating the formation of the bonds exists between Na(21) and N(ll) , the similar phenomenon exists between Na (21) and O(2) ; (2) S-omeprazole sodium and S-Ilaprazole sodium have the similar ECD spectrum, both having negative cotton effect near 300 nm mainly derived from π→π* charge transition, besides S-Ilaprazole sodium having a positive cotton effect mainly derived from π→d charge transition of benzimidazole ring to Na (21); SLansoprazole sodium, S-Pantoprazole sodium and S-Rabeprazole sodium have the similar ECD spectrum, having two negative cotton effects at 230 and 300 nm both mainly derived from the π→π* charge transition.%奥美拉唑钠、兰索拉唑钠、泮托拉唑钠、雷贝拉唑钠和艾普拉唑钠五个质子泵抑制剂分子中含有手性亚砜结构,具有一对对映异构体.为了解以上五个质子泵抑制剂分子电子结构特征和ECD谱性质,采用量子化学密度泛函理论和极化连续介质模型在B3LYP/6-311++G**水平上对上述化合物的S异构体在水溶液中的电子结构特征进行了理论研究.在此基础上,采用含时密度泛函理论在相同基组水平对其理论ECD谱进行了研究.结果表明:(1)S-奥美拉唑钠、S-兰索拉唑钠、S-泮托拉唑钠、S-雷贝拉唑钠、S-艾普拉唑钠五种质子泵抑制剂中,Na(21)与N(11)、O(2)之间均存在键鞍点,同时成键.(2)S-奥美拉唑钠、S-艾普拉唑钠的ECD谱近似,在300 nm附近均存在负性CD吸收带,主要来源于π→π*电荷跃迁；S-艾普拉唑钠在242 nm附近还存在正性CD吸收带,该吸收带主要来源于苯并咪唑环到Na(21)的π→d的电荷跃迁.S-兰索拉唑钠、S-泮托拉唑钠和S-雷贝拉唑钠的ECD谱相似,在230、300 nm附近存在两个负性CD吸收带,均来源于π→π*的电荷跃迁.
  • 摘要：The volatile oils of Idesia polycarpa Maxim fruits were extracted by different methods such as steam distillation, ultrasonic and Soxhlet extraction. The chemical compounds were separated and identified by capillary GC-MS method. The relative content of each component was calculated by area normalization. 64, 50 and 57 violatile components as listed in Table 1 were identified,and 38 components were owned by all. The main components are linoleic acid, palmitic acid, oleic acid, squalene, γ-nonalaetone and γ-Tocopherol etc.. The components extracted by steam distillation were much more comparing with other methods, while the extract rate by Soxhlet extraction were the highest.%用水蒸气蒸馏法、超声辅助浸提法和索氏提取法提取山桐子果实中的挥发油,用GCMS分离鉴定其成分并测定各成分的相对含量.水蒸气蒸馏法、超声辅助浸提法和索氏提取法分别分离鉴定出64、50和57个组分,共有化合物38种,其中主要成分为亚油酸、棕榈酸、油酸、角鲨烯、椰子醛和γ-维生素E等.3种提取方法所得山桐子果实挥发油成分有共同特征,也存在着差异,相较之下,水蒸气蒸馏法提取的挥发油成分最多,索氏提取法提取挥发油率最高.
  • 摘要：A new analysis approach for phase noise is proposed based on nonlinear stochastic differential equation. Using this method to get numerical solution of Van der Pol oscillator's phase noise produced by chaos noise and that of by white noise, by carefully compared these phase noises, which indicates that phase noise produced by chaos noise larger than that of by white noise under the same intensity conditions. By analyzing the cause of this result, some advices for guiding minimized phase noise in an oscillator design is proposed.%从描述振荡器的非线性微分方程出发,提出将噪声作为非线性微分方程的一项,通过建立随机非线性微分方程来分析振荡器的相位噪声.并用这种方法,在相同强度下,针对分别为白噪声和混沌噪声的情形,分析了Van der Pol振荡器产生的相位噪声,发现混沌噪声产生的相位噪声要远大于白噪声所产生的相位噪声.通过分析其原因,提出了一些低相位噪声振荡器设计所应考虑的问题.

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