Optical Waveguide Formed in Yb：KLu（WO4）2 Crystal by 6.0 MeV O^＋ Implantation

A planar optical waveguide is formed in monoclinic double rare-earth-tungstate laser crystal Yb：KLu（WO4）2 by 6.0 Me V oxygen ion implantation with a dose of 2 × 10^16 ions/cm^2 at room temperature. Subsequently, annealing at 300℃ for an hour in air is performed on the sample to decrease colour centres to improve the thermal stability of the waveguide. The refractive index profiles of the waveguide are reconstructed by an effective refractive index method. Dark modes of the waveguide are observed at wavelengths of 633 nm and 1539 nm. TRIM＇98 is used to simulate the damage profile caused by the implantation process. It is found that the refractive index change may be mainly due to the damage induced by the nuclear energy loss.     

Copper(Ⅱ) and 2,2′-Biimidazolyl-promoted Ullmann Coupling Reaction of Phenols and Aryl Iodides

Ullmann-type diaryl ether synthesis can be performed at 100℃ in good to excellent yields by aryl iodides asthe substrates under the assistance of copper(Ⅱ)and 2,2'-biimidazolyl.     

非连通图G_1uG_2及G_1uG_2uK_2的优美性

将k-优美图的概念进行了推广,引入了k～l 优美图及标号间距的概念,并以此为基础, 分别推出了一般情形下判定非连通图G_1 ∪G_2及G_1 ∪G_2 ∪K_2是优美图的两个充分条件;同时得出了图(C_3 ∨(?)_n)∪St(m)∪K_2是优美图,其中k、l 为自然数,l相似文献   

Study on the acoustic emission-model of concrete damage

I.lntroductiollBecausetherearethedefects.cracksandnon-homologousmicrostructurewithdifferentpropertiesincollcrete,whenaloadisputonconcretematerialthedamageandbreakagemayresultandsoonafterwardsexpanded.Itisadifficutproblem,howtodecidethedamageofconcretematerialwithcracksanddefects.TheacousticemissionisanassociatedphenomenollwiththeprocessofthenonhomologousdeformationorthebreakaeandexPansiollofmaterial.InthispaPertherelationshipbetweentheacousticemis8ionparametersandthedamageparameters,andthedam…     

分子内1,3-偶极环加成反应的研究

近几年来,人们对于1,3-偶极环加成反应的理论研究及其在合成上的应用已给予广泛的兴趣和重视。我们曾详细地研究了4-取代苯基(N-4-戊烯基)硝酮的热化学反应性能和其区域选择性以及呋哺偶极体系的热和光化学反应。本文进一步探讨了取代基效应对环加成反应的影响,利用色谱法定量地研究了取代基的电子效应与区域选择性间的关系,并对肉桂醛肟的构型及有关的反应作了研究。     

Two New Lanostane-type Triterpenoids from Mulgedium tataricum

Mulgedium tataricum L. has long been used for treatment of appendicitis, erysipelas andextravasated blood1. From the methanol extract of the whole plants, two newtriterpenoids 1 and 2 were isolated. In this paper, we report the structural elucidation ofth…     

A New Furobenzopyranone from Anaphalis lactea

A new furobenzopyranone, named anaphalisol, was isolated from the whole plant of Anaphalis lactea. Its structure was elucidated by spectroscopic methods including 2D NMR techniques.     

量子系统的能量本征值在超对称性、形状不变性框架下的计算

在超对称性、形状不变性框架下，计算了一维修正Ｐｓｃｈｌ-Ｔｅｌｅｒ势、Ｎ维氢原子和Ｎ维各向同性谐振子的能量本征值．得到的能谱公式与用通常的因子化方法得到的严格解完全一致 关键词：     

Effect of 2-Selenium Bridged β-Cyclodextrin, Glutathione Peroxidase Mimic on Stroke of Stroke-prone Spontaneously Hypertensive Rats

IntroductionStrokeisthemaindiseasethatbringsdeathormakesthepatientssufferfromlongtermdisability .Everyyearthereareabout 5millionpeopledeadfromstrokeallovertheworld .Fortheincreaseofelderlypopulationintheworld ,fewillnessesaremoredread edthanstroke[1] .Elevatedblood pressurehaslongbeenrecognizedasoneofthemostimportantlydan gerousfactors .However ,thereisincreasingevidencethatfamilialpredisposition ,orhereditaryfactors ,mayplayasignificantroleintheetiologyofstroke :strokehasbeenfoundtoshowfamil…     

A New Iridoid Glycoside and a New Iridoid from Pedicularis kansuensis f. aibiflora

A new iridoid glycoside 1 and a new iridoid 2 were isolated from the whole plant ofPedicularis kansuensis f. albiflora. Their structures were elucidated by spectroscopic methods.