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61.
Jia Chaohua 《数学学报(英文版)》1993,9(3):321-336
LetP(x) denote the greatest prime factor of IIz<n≤x+x1/2
n. In this paper, we prove thatP(x)>x
0.723 holds true for a sufficiently largex.
Project supported by the Tian Yuan Itam in the National Natural Science Foundation of China. 相似文献
62.
线圈型全光纤偏振器的研究 总被引:2,自引:0,他引:2
本文采用等效电流法对线圈型全光纤偏振器进行了分析计算.对应于保偏光纤中两正交传输基模的消光比,提出了一种分析保偏光纤弯曲损耗的新方法,这种方法基于将保偏光纤两个不同偏振模式分别等效为两个普通圆光纤的基模,等效参数通过测量不同偏振模式的模场半径来确定.实验证明这种理论计算方法与实验结果一致.最终,我们研制出的线圈型光纤偏振器在1.31μm工作波长下,实测消光比达30dB以上,工作偏振模式插入损耗≤3dB. 相似文献
63.
Fabrication of tunable colloid crystals from amine-terminated polyamidoamine dendrimers 总被引:1,自引:0,他引:1
Mingzhu Li Jingxia Wang Lin Feng Bingbing Wang Xinru Jia Lei Jiang Yanlin Song Daoben Zhu 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,290(1-3):233-238
A pH-responsive colloidal crystal was assembled using core-shell composite spheres, poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) spheres covered by generation 4 amine-terminated polyamidoamine dendrimers. The light reflection of the colloidal crystal film can be tuned at different pH due to different protonation level of the dendrimers. The method shows a facile way to fabricate diffraction-based chemical and biological sensors by exploiting the effect of photonic crystal cooperated with tunable nanoparticles. 相似文献
64.
65.
NBR/ORGANOMODIFIED BENTONITE INTERCALATED HYBRIDS AND THEIR EFFECTS ON THE TOUGHNESS OF PVC 总被引:4,自引:0,他引:4
Hybrids of intercalative nitrile-butadiene rubber/organomodified bentonite (NBR/OMB) were prepared by thelatex intercalation technique. Investigation of their mechanical properties and the microstructore of NBR/OMB showed thatthe organomodified bentonite is an effective toughener for NBR. Transmission electronic microscopy (TEM) and X-rnydiffraction (XRD) tests showed that the NBR macromolecule could be intercalated into the galleries of bentonite.Incorporation of NBR/OMB hybrids as tougheners into poly(vinyl chloride) (PVC) results in a substantial increase in theimpact strength of PVC, but little decrease in its tensile strength and flexural strength, compared to the unmodified PVC. 相似文献
66.
Li X Yu C Sun W Liu G Jia J Wang Y 《Rapid communications in mass spectrometry : RCM》2004,18(23):2878-2882
A rapid, sensitive and specific isocratic liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the simultaneous quantitative determination of magnesium lithospermate B (MLB), rosmarinic acid (RA), and lithospermic acid (LA) in beagle dog serum, with silibinin as internal standard. The serum samples were treated by liquid-liquid extraction and analyzed using LC/MS/MS with a TurboIonSpray source. A short run-time (3 min) fulfilled the need for monitoring serum levels of MLB, RA, and LA in large-scale studies. The calibration curves for MLB, RA, and LA were linear over the ranges 8-2048, 4-1024, and 4-1024 ng/mL, respectively, with coefficients of correlation >0.999. The intra- and inter-day precision (CV) of analysis was <10%, and accuracy ranged from 90-104%. This quantitation method was successfully applied to a pharmacokinetic study of salvianolate administrated by intravenous infusion with dosage of 6 mg/kg in beagle dogs. 相似文献
67.
Borohydride exchange resin-transition metal(Co,Ni,Cu,)compoundsystems reduced C=C double to C-C single bond in ethanol. 相似文献
68.
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