排序方式: 共有76条查询结果,搜索用时 15 毫秒
41.
42.
YANG Zongxin School of Mathematics Information Science Jiangxi Normal University Nanchang China. 《数学年刊A辑(中文版)》2007,(6)
研究了一族由Pokornyi单叶性判据所确定的Nehari函数的偏差性质,得到了这类函数的导数增长和球面度量偏差,并研究了与John区域有着密切的关系的一个函数的特征. 相似文献
43.
纳米晶BaMgAl10O17:Eu复合氧化物的合成及发光特性 总被引:3,自引:1,他引:2
采用溶胶-凝胶法制备了纳米晶BaMgAl_(10)O_(17):Eu蓝色荧光粉,并对其进行了表征。结果表明:与微米晶相比,纳米晶的XRD图谱展宽,随着Eu~(2 )浓度的增加,表现为荧光猝灭;荧光猝灭源于晶格迁移。 相似文献
44.
偏最小二乘-吸光光度法同时测定食用香料香兰素和乙基香兰素 总被引:4,自引:0,他引:4
在紫外区香兰素、乙基香兰素均有吸收,但它们的吸收光谱重叠严重,难以进行单一组分的直接分析。本文在pH=2.87的B-R缓冲溶液中对香兰素和乙基香兰素两组分混合溶液进行光度测定,所得的重叠波谱数据用偏最小二乘法(PLS)处理,并用于食品样品的测定,获得了较好的定量分析结果。香兰素和乙基香兰素的线性范围均为1.0-20.0mg·L-1;检出限分别为:0.4782mg·L-1、0.4499mg·L-1。 相似文献
45.
低温下C60拉曼谱线的强度变化 总被引:1,自引:0,他引:1
测量了284-10K范围内C60的拉曼谱,作了了拉曼谱线的强度-温度曲线。这些曲线都在一级相变点250K附近呈现突变:Ag模谱线的强度及其变化都显著大于Hg的:1470,498cm^-1二者的曲线起伏趋势完全相反。 相似文献
46.
本文考虑下面的Dirichlet问题利用粘性解理论证明了;当H,Г满足一定条件时,(DP)的粘性解u(x,t)满足:如果ψ∈Ca,a/2,则u(x,t)∈Ca,a/2,若ψ=0,则u(x,t)是Lipschitz连续的. 相似文献
47.
A new flavonoid glucoside from Cassia angustifolia 总被引:1,自引:0,他引:1
A new flavonoid glucoside with a known one was isolated from the leaves of Cassia angustifolia.Based on the spectral analysis, including MS,~1H NMR,~(13)C NMR,DEPT,~1H-~1HCOSY,HMQC,HMBC and NOSEY,their chemical structures were determined as kaempferol-3-O-[(6′′′-O-trans-sinnapoyl)-β-D-glucopyranosyl(1→)]-β-D-glucopyranoside 1 and apigenin-6,8-di-C-glycoside 2. 相似文献
48.
Two new C-glucoside oxanthrones,6-methoxyl-10-hydroxyaloin A(1) and 6-methoxyl-10-hydroxyaloin B(2),were isolated from the roots of Rumex gmelini Turcz.Their structures were elucidated on the basis of spectroscopic techniques and chemical means. 相似文献
49.
DENG GuoHua & LIANG HuaSchool of Finance Statistics Jiangxi University of Finance Economics Nanchang China 《中国科学 数学(英文版)》2010,(5)
To improve the prediction accuracy of semiparametric additive partial linear models(APLM) and the coverage probability of confidence intervals of the parameters of interest,we explore a focused information criterion for model selection among ALPM after we estimate the nonparametric functions by the polynomial spline smoothing,and introduce a general model average estimator.The major advantage of the proposed procedures is that iterative backfitting implementation is avoided,which thus results in gains in co... 相似文献
50.
本文报导了以SnO2、ZnO和γ—F?2O3三种半导体金属氧化物按一定比例混合后作为基体材料制成的气敏元件,实验表明,这种元件对C4H10敏感 相似文献