高效液相色谱法测定咪唑中2-甲基咪唑和4-甲基咪唑

采用高效液相色谱法测定咪唑中2-甲基咪唑和4-甲基咪唑的含量。采用XDB C18色谱柱为分离柱,以pH 3.5的0.05mol·L-1磷酸二氢钾缓冲溶液与甲醇以体积比95比5组成的混合溶液为流动相,流量为1.0mL·min-1,在波长210nm处进行二极管阵列检测。2-甲基咪唑和4-甲基咪唑均在0.10~25.0mg·L-1范围内与其峰面积呈线性关系,检出限(3S/N)分别为20,40mg·kg-1。在1.00,5.00,20.0mg·L-1 3个浓度水平进行加标回收试验,回收率在89.0%~103%之间,测定值的相对标准偏差(n=7)在0.58%~3.0%之间。     

具有衰减记忆的多维映射的逼近和系统识别

本文主要研究具有衰减记忆的多维映射的逼近，考虑了因果和非因果两种情形。在实际应用上，可以用来识别一类因果和非因果系统。     

具有衰减记忆的多维映射的逼近和系统识别(英)

本文主要研究具有衰减记忆的多维映射的逼近，考虑了因果和非因果两种情形．在实际应用上，可以用来识别一类因果和非因果系统．     

Photoluminescence from site-selected coupling between quantum dots and microtoroid cavities

By using CdSe/ZnS quantum dots （QDs）, we study the effect of cavity quantum electrodynamics on the coupling of the microtoroid cavity. When with whispering gallery （WG） modes, the microtoroid cavity demonstrates high quality factor and small mode volume at visible wavelengths. Accordingly, fiber tapers allow QDs to adhere into the cavity and further permit the control of site-selected coupling. From the luminescence spectra, QDs are modulated effectively by cavity modes, Variable modulations are observed by changing QD coupling conditions. Therefore, based on experimental and theoretical research, strong and tunable Purcell enhancement can be realized by this system.     

Fabrication of SiO_2 microdisk optical resonator

The silica microdisk optical resonator which exhibits whispering-gallery-type modes with quality factors of 9.67×10~4 is fabricated with photolithographic techniques.Reactive ion beam etching(RIBE)is used to get the silica disks with photoresist masks on SiO_2/Si made by standard ultraviolet(UV)photolithography, and spontaneous silicon etching by XeF_2 is used to fabricate the silicon micropillars.This fabrication process can control the microcavity geometry,leading to high experiment repeatability and controllable cavity modes.These characteristics are important for many applications in which the microcavity is necessary,such as the quantum gate.     

巧用三角函数表妙解题

我们知道.解Rt△时要用到三角函数表.主要是查三角函数值;当然,一边可用来查角,不过不很精确.“巧”就巧在利用这“不精确”. 题目四边形AB-CD内接于⊙O,圆半径为5.AB=6,BC=7,CD=     

费马(分割)定理的一个简捷证法

费马(分割)定理 矩形ABCD的边AD=AB/2~(1/2),以AB为直径向外作半圆,取半圆上任意点P,连PC、PD交AB于E、F点,则AE2+BF2=AB2. 文(1)中给出了一个代数证法,但其过程冗长繁杂,难以阅读;文(2)将其改进,使其证法较易理解,本文将给出一个十分简捷的     

Fiber taper coupled high-quality-factor planar microdisk

A fiber taper can evanescently couple to whispering gallery modes (WGMs) in a planar silica microdisk for observing the optical properties of the microdisk cavity.It is revealed that WGMs have very high quality (Q) factors by controlling the air gap between the taper and the microdisk.The best coupling efficiency from the taper to the microdisk is as high as 98%,and can be continuously adjusted from the under-coupling,critical-coupling to over-coupling regimes.The influence of the laboratory circumstance such as surface contamination on the microdisk is also discussed.It is experimentally shown that the high-Q-factor (10~5) modes can be kept for a long period in a general laboratory circumstance.