简介:AnewlygrownBaGa4Se7crystalhasbeensynthesizedviatheBridgman-Stockbargertechnique.Thisnewcrystalhasadvantagesofhighnonlinearoptics(NLO)coefficients,highlaserdamagethresholds,andwidetransparentregions.TheBaGa4Se7crystalhasbrightapplicationprospectsasanonlineargainmediuminmid-infraredandterahertzregions.Inthispaper,thecrystallinestructureandsyntheticmethodoftheBaGa4Se7crystalareintroduced.Therefractiveindicesandabsorptioncoefficientsalongthreedielectricaxesbetween0.1THzand1.0THzarealsoobtained.Theterahertzdifferencefrequencygeneration(THz-DFG)characteristicsbasedontheBaGa4Se7crystalinthefrequencyrangeof0.1THzto1.0THzareanalyzedtheoreticallyandthephase-matchingconditionsarecalculated.TheapplicationofBaGa4Se7crystalsinterahertzwavegenerationisalsodiscussed.
简介:为满足广大发烧友对高性价比放大器产品的需求,天逸最近推出了一款在音质音色上与高端的纯甲类AD-2N放大器非常接近,价格更吸引人的AD-99合并式甲类放大器。AD-99是在AD-2N放大器的基础上,对外观工艺、内部工艺及整机用料进行优化整合而推出的。即使如此,AD-99的用料也不是能省即省,在影响音质的主要通道和电源滤波部份,选用了美国BB公司的OPA2134运放、MKP聚丙稀电容、70000μF的名牌音频专用电解及500W的巨型的优质大环牛。而机器的功率输出级则采用了大电流高偏置电路以消除功率管的开关失真,更保证了纯甲类工作状态下的表现,是性价比十分高的一款放大器。
简介:WefabricatepolycrystallineCu(In,Ga)Se2(CIGS)filmsolarcellsonpolyimide(PI)substrateattemperatureof450°Cwithsingle-stageprocess,andobtainapoorcrystallizationofCIGSfilmswithseveralsecondaryphasesinit.Forimprovingitfurther,thetwo-stageprocessisadoptedinsteadofthesingle-stageone.AnextraCu-richCIGSlayerwiththethicknessfrom100nmto200nmisgrownonthesubstrate,andthenanotherCu-poorCIGSfilmwiththicknessof1.5-2.0μmisdepositedonit.Withthemodificationoftheevaporationprocess,thegrainsizeofabsorberlayerisincreased,andtheadditionalsecondaryphasesalmostdisappear.Accordingly,theoveralldeviceperformanceisimproved,andtheconversionefficiencyisenhancedbyabout20%.
简介:Chalcopyrite-typeCuInSe2nanoparticlesaresuccessfullypreparedbyusingIn2Se3nanoparticlesasaprecursorreactedwithcopperchloride(CuCl)solutionviaaphasetransformationprocessinlowtemperature.Thereactiontimeisakeyparameter.Afterthereactiontimeincreasingfrom0.5hto8h,In2Se3andCuClreactwitheachothergraduallyviaphasetransformationintoCuInSe2withoutanyintermediatephase.ThecrystallinestructureandmorphologyoftheCuInSe2nanoparticlesarecharacterizedbyX-raydiffraction(XRD)andfieldemissionscanningelectronmicroscopy(FESEM).ThediameterofCuInSe2nanoparticleswithgooddispersibilityrangesfrom10nmto20nm.ThebandgapoftheCuInSe2nanoparticlesis1.04eVcalculatedfromtheultraviolet-visible(UV-VIS)spectrum.
简介:在英国伦敦,每当夜幕降临,约近十万人会来到音乐厅、歌舞厅,就一座城市而言,这个数字意味着什么样的概念呢,我想,绝对不是一个量的关系,它代表了一个民族整体的文化素质、音乐涵养、艺术情操。那么,在这样一个国度设计生产的音响器械,必然隐藏着原始积累的元素,厚积而薄发,这种与生俱来的气质就是他们产品的价值。当我们今天接触英国许多音响器材:君子、莲、音乐传真、英国之宝的产品,诚然体会到一种博大而深厚的文化底蕴和格调高雅的美。近期,依然来自英伦的QCAD99系列,更是带着多姿的人文色彩进入我们的视野,亦是本文将要介绍的主角。
简介:以往,选用手持式还是台式万用表是有明确的界限的。如果你做设计工作或需要很高的精确度,那么就应选择台式万用表。而今天,日益变小的元件使得手持式万用表和台式表的性能差异变得很小。手持式万用表已接近如式表的性能。它们基本可以交换使用。