An Improved Blue Polymer Light-Emitting Diode by Using Sodium Hydroxide/Ca/Al Cathode

The performance of blue polymer light-emitting diodes （PLEDs） based on poly（9,9-dioctylfluorene） （PFO） is improved by introducing a thin layer of sodium hydroxide （NaOH） between the calcium cathode and the PFO emissive layer. By replacing the commonly used Ca/Al cathode by a NaOH （2.5nm）/Ca （10nm）/Al cathode, the driving voltage is reduced from 8.3 V to 5.4 V and the light-emitting efficiency is enhanced from 0.46cd/A to 0.72cd/A for achieving a luminance of 500cd/m^2, respectively. Moreover, the device with NaOH/Ca/Al cathode shows a pure blue emission of （0.17, 0.12） at high brightnesses. These improvements are attributed to introduction of a thin layer of NaOH that can lower the interracial barrier and facilitate electron injection.     

半群DkTn的秩和平方幂等元秩

设自然数n≥3,T_n和S_n分别是有限集X_n={1,2,…,n}上的全变换半群和置换群.对任意正整数k满足1≤k≤n,记D_k=k,δ_k>,其中对任意的x∈{1,2,…,k-1}有xg_k=x+1,k_gf=1且对任意的x∈{k+1,…,n}有x_gk=x;对任意的x∈{1,2,…,k}有xδ_k=k+1-x且对任意的x∈{k+1,…,n}有xδ_k=x.易见D_k是S_n的子群,称D_k是X_n上的k-局部二面体群,再记D_kT_n=D_k∪(T_nS_n).易证D_kT_n是全变换半群T_n的子半群.通过分...     

结构光照明光切片显微图像的高保真重构方法

光切片图像的质量与使用的重构算法直接相关,传统的均方根算法虽然简洁,但在原始图像信噪比和条纹对比度不高时重构效果不佳,得到的三维重建结果并不理想。针对该问题,提出一种去背景和去卷积相结合的光切片方法。与传统均方根算法相比,该方法能有效减少残留条纹,提高微小细节的可见性。实验搭建了一套基于数字微镜器件的结构照明显微系统,以小鼠肾脏细胞、牛肺动脉内皮细胞等为样品进行了光切片实验。实验结果表明,该方法能获得更好的光切片和三维成像效果。     

平移桁架结构分析

平移桁架及其结构特征在精密观测和测量中,有时希望两个物体在侧向外力(如重力、风力等)作用下保持平行而无转动.例如大型天文望远镜的光学部件之间以及安装观测仪器的平台与地面之间等(图 ...     

热处理对SILAR法制备CuInSe2薄膜性能的影响

CuInSe₂ ternary films were prepared by successive ionic layer absorption and reaction (SILAR) method. The films were deposited on glass substrates at room temperature and subject to heat-treatment under Ar atmosphere at various calcination temperatures, and then characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), optical absorption spectroscopy. XRD results showed that chalcopyrite structure CuInSe₂ with high degree of preferred orientation towards (112) reflection could be obtained by post-heat treatment. The compositions of films calcined at 300～400 ℃ were close to the standard stoichiometry and Cl impurity decreased after calcination. The direct band gap increased from 0.94 eV to 0.98 eV with the increase of calcination temperature.     

金属镍中微量镁的二甲苯胺蓝Ⅱ比色测定法

金属镍中微量镁的测定方法,大都采用预先分离镍等干扰元素,然后进行比色测定。其中汞阴极电解分离比色法较常用,但该法结果不够稳定,往往还需再经铜试剂-氯仿萃取分离,手续繁琐。离子交换分离比色法及其它几种方法,都存在着或者分离手续冗长,或者需用大量氰化钾,或者方法的灵敏度不能满足要求等不足之处。最近几年来发展了原子吸收分光光度法,此法灵敏度高,且不经复杂的分离手续,可直接进行测定,是一种测定镁的最为简便、快速的方法,但因条件所限,目前尚未能广泛使用。     

铒—谷氨酸配合物的晶体结构及表征

合成了铒与Ｌ－谷氨酸形成的配合物［Ｅｒ２（Ｌ－Ｇｌｕ）２．（Ｈ２Ｏ）８］［ＣｌＯ４）４．３Ｈ２Ｏ，由元素分析、红外光谱、热分析对配合物进行了表征。得到了配合物的单晶，该晶体属于单斜晶系，空间群Ｐ２１，晶胞参数ａ＝１．９９８７（３）ｎｍ，ｂ＝１．６５０５（３）ｎｍ，ｃ＝１．１０４０（２）ｎｍ，β＝１０４．６９（１）＾ｏ，Ｖ＝３．５３８ｎｍ＾３，Ｚ＝２，Ｒ＝０．０４３。晶体结构中每一个独立区含有二个晶     

加速溶剂萃取-高效液相色谱串联质谱法测定土壤中邻苯二甲酸酯

建立了高效液相色谱串联质谱技术(Liquid chromatography tandem mass spectrometry,LC-MS/MS)同时测定土壤中邻苯二甲酸酯(Phthalic acid esters,PAEs)的分析方法。确定了土壤样品加速溶剂萃取最优条件是以正己烷为萃取溶剂,在160℃下,静态萃取4次,每次12 min,萃取液经旋转蒸发浓缩,以乙腈-0.1%甲酸溶液为流动相梯度洗脱分离后,用LC-MS/MS结合大气压化学源(Atmospheric pressure chemical ionization,APCI)进行定性及定量分析。土壤中11种PAEs的浓度与其峰面积呈良好的线性关系,检出限为0.03~13.0μg/kg,样品的加标平均回收率为72.8%~101.8%,相对标准偏差(RSD)为1.7%~6.7%。方法简便快速,且灵敏度高,适用于土壤中11种邻苯二甲酸酯的同时测定。     

METAL COMPLEXES OF POLYCYCLIC TERTIARY. AMINES. PART VIII. SYNTHESIS AND CRYSTAL STRUCTURE OF 1,4-DIAZABICYCLO[2.2.2]OCTANEPENTACARBONYLMOLYBDENUM(0), (CH_2)_6N_2·Mo(CO)_5

<正> C11H12N2MoO5, Mr = 348.17, orthorhombic, space group p212121,a= 7.048(1), b = 11.060(4), c = 18.039(7) A, V = 1406.2(8) A3, Z = 4, D x=1.645, Dm = 1.61 (flotation in aqueous KI) g cm-3 , graphite-monochromatizedMo-Kα,λ = 0.71069 A, μ = 9.25 cm-1, F(OOO) = 695.73, T = 295°K, final RF =0.035 and RwF2 = 0.051 for 1335 observed reflections with |F0| > 3σ(|F0|). The measured molecular dimensions.reflect the trans influence and steric bulk of the organic cage ligand.     

拉曼光谱检测系统的搭建及在仪器分析基础实验教学中的应用*

报道了一种可由学生自行搭建的拉曼光谱检测系统,并设计了配套的实验内容,引入了前沿的表面增强拉曼光谱(SERS)技术,应用于牛奶中违法添加物三聚氰胺的检测。学生通过对仪器的组装和测试,可以更加深入地理解科学仪器的结构和工作原理,有助于提高学生的动手能力和创新思维。