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1.
乙酰基和丙酰基紫外光解的研究   总被引:3,自引:0,他引:3  
运用时间分辨红外发射光谱仪,研究了CH3CO和C2H5CO自由基在248nm的激光光解,观察到了高振动激发产物CO。光解机理的分析表明,光解可 资用能还未能在自由基内充分分散,很快发生了解离。  相似文献   

2.
以NH4Cl作助溶剂,碳还原硫酸钙的方法合成了CaS:Ce。在紫外光激发下,CaS:Ce中存在着Ce^3+的^2D-^2F5/2(500nm)和^2D-^2F7/2(550nm)跃迁发射,但在蓝色光激发下,只有波峰为532nm半宽度为92nm的宽带发射。当Ce^3+的浓度为0.075mol%时,^2D-^2F5/2跃迁发射强度与^2D-^2F7/2跃迁发射强度相等,而532nm发射猝灭。  相似文献   

3.
利用532nm的激光对碘乙烷(C2H5I)分子作了多光子电离解离(MPID)质谱(MS)研究。C2H3I分子吸收532nm激光双光子的能量激发跃迁至A带后,碎裂成中性碎片I原子及C2H5自由基,中性碎片再吸收光子经一系列电离解离形成碎片离子,分析了不同激光强度及加速电压下的产物离子与总的碳氢离子哟度比值变化,从而更深地揭示了C2H5I分子在532nm激光作用下的MPID机理。  相似文献   

4.
用γ射线辐照法制备出以γ-Al2O3为载体的纳米级CuO(8wt.%,12nm)-Pd(0.5wt%,10nm)催化剂在CO氧化反应中有很高的活性,当催化反应温度为110℃、145℃和148℃时,则CO转化率分别为5%、50%和100%。此催化剂在750℃热处理后,仍显示较高的活性,表明它具有一定的热稳定性。  相似文献   

5.
本文将表面等离子激光衰减-单电子激发光电发射理论应用于Ag一O-Cs光电阴极的发射机理的研究,对其发射机理提出了一个新的观点,即认为Ag-O-Cs光电阴极量子产额在800.0nm附近的峰值是由Cs_(11)O_3表面等离子激发所产生,并用这个观,久解释了一些实验现象  相似文献   

6.
束嵘  周映雪 《发光学报》1998,19(3):245-247
在国家同步辐射实验室的时间分辨光谱站(U10B光束线)研究掺杂Eu2+的卤磷酸盐:(Ca,Sr,Ba)5(PO4)3ClEu2+样品和(Ca,Sr)5(PO4)3ClEu2+的真空紫外辐照特性、反射光谱.前者在185nm光的激发下,60分钟内没有观察到明显的发光强度下降;而后者在185nm光的激发下,15分钟内就可以观察到其450nm发光的明显变化,从强到弱,直至完全消失.测量了两种样品的反射谱(100nm至400nm),并根据K-K关系计算得出的吸收谱,我们认为:由于Ba2+的加入,改变了晶格对称性,(O)-色心的能级发生变化,晶体对185nm附近紫外光的吸收明显降低,从而起到了耐185nm辐照的作用  相似文献   

7.
制备了四氯四铜酸苯铵盐(C6H5NH3)2CuCl4单晶,Mr=187.26,由四园衍射数据确定了晶体结构,晶体属单斜晶系,空间群P21/a,a=0.7184(1),b=0.7448(2),c=1.5070(4)nm,β=100.67(2)°,V=0.7924nm^3,Z=2,Dx=1.650gcm^-3,(Mo,Ka)=0.071069nm,μ=4.056mm^-1,F(000)=389,R=0  相似文献   

8.
本文用ESR方法考察了Cp_2Zr(H)Cl与RNCS(R=C_6H_5,c-C_6H_(11),n-C_4H_9)的反应的过程,结果表明,在这类反应过程中,Zr-H键发生均裂,中心金属锆经过+4─→+3─→+4的价态变化,反应通过自由基机理进行.  相似文献   

9.
何京良 《光学学报》1998,18(7):62-865
报道一种激光二极管端面泵浦NdYVO4晶体、LBO腔内倍频的全固态瓦级连续波(CW)绿光激光器。对LBO采用I类非临界相位匹配(NCPM)、温度调谐,当泵光功率为5.5W时,获得了1.2WTEM00模532nm连续波绿光输出,光-光转换效率达22%,电-光转换效率达3%。  相似文献   

10.
硫氰酸铵树脂相分光光度法同时测定天然水中微量铁和钴   总被引:4,自引:0,他引:4  
研究了在Tween-80存在的酸性介质中,Fe(Ⅲ)和Co(Ⅱ)与SCN^-形成稳定的有色络阴离子与阴树脂交换吸附,有色络合物富集显色于树脂组上,进行树脂组分光光度集显色于树脂相上,进行树脂相分光光度法同时测定铁和钴的实验条件,Fe(Ⅲ)和Co(Ⅱ)树脂具有色络合物最大吸收波长λmax分别为490nm和630nm,摩尔吸光系数,ε为2.4×10^5L.mol^-1.cm^-1和2.1×10^5L.  相似文献   

11.
彭杰  曾人杰  李郎楷 《发光学报》2012,33(9):966-972
采用非均相沉淀法制备了Sr3-xSi1-xAlxO5∶xCe3+荧光粉,并与高温固相法制备的该荧光粉进行了对比。以XRD、SEM和荧光光谱分析来表征所制备的荧光粉。结果表明,非均相沉淀法比高温固相反应法制备的荧光粉相纯度更高,颗粒分布更窄,晶面清晰,团聚程度小,相对发光强度也更高。荧光粉的激发光谱为270~500 nm的双峰宽带,最强激发峰位于417 nm处。发射光谱为450~700 nm的单峰宽带,峰值位于525 nm处。电荷补偿剂对荧光粉相对发光强度影响较大,外加Al3+置换Si4+作为电荷补偿剂比外加Li+置换Sr2+的效果更好。  相似文献   

12.
以钛酸四丁酯为前驱物,采用溶胶-凝胶法制备了四种不同配方Eu3+掺杂的TiO2纳米晶.利用扫描电镜(SEM)、EDS能谱、光致发光光谱对样品的形貌、成份及性能进行了表征.研究了退火温度、稀土Eu3+离子掺杂摩尔分数、溶剂乙醇量等对发光性能的影响,并对其发光机理进行了探讨.结果表明:稀土Eu3+掺杂TiO2纳米晶样品,掺杂均匀、颗粒大约在30~80 nm|从EDS能谱分析可得Ti:O原子个数比并不是按化学计量TiO2满足1:2,这是因为在TiO2中形成的是Ti-O-Ti键,Eu3+离子很可能取代了Ti4+离子,同时又形成了氧空位,表明稀土Eu3+离子进入TiO2晶格中|样品的主发射峰在614 nm(5D0→7F2)处发光最强,且在593 nm(5D0→7F1)处出现了属于磁偶极跃迁的发射峰,制备Eu3+∶TiO2纳米晶的组分、退火温度、溶剂乙醇的量不同,发射光谱的强度也不同.  相似文献   

13.
In this paper, we present and analyse the optical characteristics, such as spectral shift, CIE coordinates, viewing angle dependence, luminous current efficiency and luminous power efficiency, of an organic light-emitting device (OLED) with a commercial diffuser film or a brightness-enhancement film (BEF) attached. Compared to a planar green OLED, the luminous current efficiencies of the OLED with an attached diffuser film or BEF increase by 29% and 23%, respectively. The overall luminous power efficiencies are enhanced by 28% and 7%. Compared to the planar green device, we observe blue shifts at different viewing angles when microstructured films are attached, which is the evidence that the waveguiding modes are being extracted. In our planar OLED, the peak wavelength blue shifts and the full width at the half maximum (FWHM) decrease with increasing viewing angles due to the microcavity effect. When the diffuser is attached, the spectral peak has a constant blue shift (6 nm) compared to that of the planar OLED. On the other hand, in the BEF case, the spectral shift depends on the viewing angle (2-12 nm blue shifts from 0 to 80°). This is due to the different operating principles (scattering and redirected light) of the diffuser and BEF. Since the transmittance spectra of both the diffuser film and the BEF are flat over the visible range, it is suitable for lighting applications by using white OLED. When attaching the films on a commercial white OLED, the luminous current efficiencies of the OLED with an attached diffuser film or BEF increase by 34% and 31%, respectively. The overall luminous power efficiencies are enhanced by 42% and 8%.  相似文献   

14.
利用光学发射谱技术对直流辉光放电等离子体增强的化学气相沉积氮化碳薄膜过程中的等离子体进行了原位诊断,结果表明主要的辐射有N2的第二正系跃迁、N2^ 的第一负系跃迁、CN和NH的紫外跃迁。研究了气源中氢气含量、放电电流及沉积气压的变化对N2(337.1nm),N2^ (391.4nm)和CN(388.3nm)辐射强度的影响,并在此基础上探讨了这几种跃迁的激发机制,其结果为氮化碳合成中优化沉积参数、控制实验过程提供了依据。  相似文献   

15.
荧光粉比例对白光LED特性的影响   总被引:1,自引:0,他引:1  
Guo WL  Cui DS  Cui BF  Yan WW  Liu Y 《光谱学与光谱分析》2011,31(10):2680-2683
用黄色和橙色硅酸盐荧光粉制备了白光LED,调整黄粉和橙粉的比例得到不同的色温.对样品进行光学测试,发现黄粉与橙粉的比例小于7时,黄光部分的峰值约590 nm,比例大于7时,黄光部分的峰值约570 nm;显色指数和流明效率都是随色温的增大先上升后下降,5521 K时达到最优值,这是由于低色温时,荧光粉的浓度大导致不能有效...  相似文献   

16.
YxVO4:0.01Dy3+ and Y0.99-xVO4:0.01Dy3+,xBi3+ phosphors were synthesized by chemical coprecipitation method.Their crystal structure,micromorphology and photoluminescence (PL) properties were investigated by X-ray diffraction (XRD),scan electron microscopy (SEM) and spectrofluorometer.YxVO4:0.01Dy3+ and Y0.99-xVO4:0.01Dy3+,xBi3+ phosphors have a broad excitation band from about 250 to 350 nm including a strongest peak at about 310 nm.Under its excitation,the emission spectra exhibits two sharp peaks,one of which centered at about 483 nm for 4 F9/2→6 H15/2 transition of Dy3+ and the other at about 574nm due to the 4F9/2→6H13/2 transition of Dy3+.For YxVO4:0.01Dy3+ (x=0.94,0.97,0.99,1.01,1.03)phosphor,with increasing value of x,the body color of phosphor changes from yellow to white and the strongest peak in the excitation spectra shifts a little to shorter wavelength.It is detrimental to luminous intensity when Y3+ content deviates stoichiometric ratio.For Y0.99-xVO4:0.01Dy3+,xBi3+ (x=0.01,0.05,0.1,0.15,0.2,0.25) phosphor,the samples have extraneous bismuth vanadium oxide phase except for the major tetragonal zircon structure when x≥0.20.With increasing value of x,the band edge in the excitation spectra shifts to longer wavelength,the excitation intensity and luminous intensity increase early and decrease late.When the value of x is 0.01,the intensities increase evidently.In addition,the influence of Y3+ or Bi3+ on the color temperature of emission and micromorphology of YVO4:Dy3+ is slight.  相似文献   

17.
The ultrasensitivity of the cavity ring down spectroscopy technique has been used to detect the minor CN species in a premixed rich (φ=1.2) methane/air flame stabilized at 53 hPa. The CN radical has been probed around 387 nm on the B–X (0–0) band. A peak concentration of 4.7·109 cm−3 has been measured which corresponds to a mole fraction of 0.022 ppm. A detection limit of a few ppb has been reached despite the presence of an important off-resonance background due to the flame.  相似文献   

18.
Silicon nanowires (SiNWs) were grown on an Au-coated Si(111) substrate at various gas pressures by very high frequency plasma enhanced chemical vapor deposition via the vapor–liquid–solid mechanism. The synthesized SiNWs were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, Raman spectroscopy and photoluminescence (PL). The SiNWs were sharp needle-shaped and possessed highly crystalline core and oxide amorphous shell. As the gas pressure increases from 70 mtorr to 85 mtorr, the average diameter of the SiNWs decreases from 250 nm to 70 nm. Furthermore, the density of the nanowires increases with the gas pressure. The PL spectra revealed a peak at about 400 nm and a broadband emission at about 700 nm.  相似文献   

19.
新型蓝色磷光嘧啶铱(Ⅲ)配合物的合成及发光性质   总被引:1,自引:1,他引:0       下载免费PDF全文
设计并合成了以2-(2,4-二氟苯基)嘧啶(DFPPM)为主配体的两种新型二嗪铱配合物 (Ph:苯基)和,用核磁共振(NMR)和质谱等方法对其进行了表征,并用紫外-可见吸收光谱和光致发光光谱对其光学性质进行了研究。光致发光光谱结果显示:配合物 的发射峰波长为472 nm和489 nm;而配合物 的发射峰波长为447 nm和472 nm,1931CIE色度坐标为(0.14,0.15),是一种深蓝色磷光材料。以 为客体材料、PVK为主体材料制备了电致发光器件,研究了其电致发光光谱。结果表明,电致发光光谱与光致发光光谱相比有较大程度的红移。  相似文献   

20.
乔泊  赵谡玲  徐征  徐叙瑢 《中国物理 B》2016,25(9):98102-098102
The ZnO quantum dots (QDs) were synthesized with improved chemical solution method. The size of the ZnO QDs is exceedingly uniform with a diameter of approximately 4.8 nm, which are homogeneously dispersed in ethanol. The optical absorption edge shifts from 370 nm of bulk material to 359 nm of QD materials due to the quantum size effect, while the photoluminescence peak shifts from 375 nm to 387 nm with the increase of the density of ZnO QDs. The stability of ZnO QDs was studied with different dispersion degrees at 0 ℃ and at room temperature of 25 ℃. The agglomeration mechanisms and their relationship with the emission spectra were uncovered for the first time. With the ageing of ZnO QDs, the agglomeration is aggravated and the surface defects increase, which leads to the defect emission.  相似文献   

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