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Improved Quantum Efficiency of Organic Light Emitting Diodes with Gradiently Doped Double Emitting Zone

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Chinese Physics Letters 2003年第6期20卷 938-941页

作者： GAOWen-Bao JIANGWen-Long SUNJia-Xin PENGJing HOUJing-Ying LIUShi-Yong NationalLaboratoryofIntegratedOptoelectronics JilinUniversityChangchun130023 ElectronicInformationandEngineeringDepartment JilinNormalUniversitySiping136000

We investigate electroluminescent characteristics of gradiently doped organic light-emitting diodes, which were gradiently doped in both the hole and the electron-transporting layer to form a double emitting zone. The device structure was ITO/(15nm) CuPc/(60nm)NPB:rubrene/(30nm)Alq3:rubrene/(20nm)Alq3/(0.5nm)LiF/Al. We observed that charge carriers were well trapped by the dopant molecules and the main emitting zone was localized at the NPB:rubrene side close to the interface of NPB:rubrene/Alq3:rubrene. The quantum efficiency (cd/A) was enhanced to 5.89cd/A at 6V. We attributed this improvement to the charge carriers trapping and the emitting of the double emitting zone.

关键词： Quantum efficiency

Mechanical Property of Low Chromium Semi-Steel Grinding Ball Prepared by Cross Rolling

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Journal of Iron and Steel Research(International) 2004年第5期11卷 50-54页

作者： CHANGLi-min MENGDe-liang NIEPu-lin LIUJian-hua jilinnormaluniversity Siping136000China YanshanUniversity Qinhuangdao066004China

The preparing method,rolling technology and mechanical properties of low chromium semi-steel grinding ball by cross rolling were studied.The results show that when the low chromium semi-steel bar is forged from55mm to50mm,cross-rolled into grinding ball at 1 000-1 050℃,air cooled and tempered at 550℃for 2h,the best mechanical properties,especially the abrasive resistance under the action of hard abrasive,can be obtained.

关键词： low chromium semi-steel grinding ball cross rolling mechanical property

Synthesis， Crystal Structure and Quantum Chemistry of a Pb(II) Coordination Polymer Based on Adipic Acid and Phenanthroline Derivatives

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Chinese Journal of Structural Chemistry 2021年

作者：潘亚茹李秀梅刘博周实 FacultyofChemistry，TonghuaNormalUniversity FacultyofChemistry，jilinnormaluniversity

A new Pb（II） coordination polymer， [Pb（adip）(L);];(1， H;adip = adipic acid， L = 2-（4-N，N?-dimethylphenyl）- 1-H-imidazo[4，5-f][1，10] phenanthroline)， was synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction， powder XRD， FT-IR， thermogravimetric， fluorescence spectrum and elemental analysis techniques. Complex 1 crystallizes in triclinic system， space group P1 with a = 11.406（3）， b = 12.036（4）， c = 17.520（5） ?， V = 2228.3（11） ?;， M;= 1028.09， D;= 1.532 g·cm;， F（000） = 1024， μ（MoKα） = 3.842， R;= 0.0274 and Z = 2. The final R = 0.1055 and wR = 0.3277 for 6954 observed reflections with I > 2σ（I）. It features a one-dimensional chain linked by adip;ligand. Moreover， complex 1 exhibits strong green luminescence with emission peak of 514 nm. In addition， the quantum-chemical calculations were accomplished on ?molecular fragments? extracted from the crystal structure of 1 using the PBE0/LANL2DZ method built in Gaussian 16 Program. The calculation values denoted the distinct covalent interaction between the coordinated atoms and Pb（II） ion.

关键词： coordination polymer hydrothermal synthesis crystal structure luminescence property quantum-chemical

High-Efficient Organic Light-Emitting Diodes Using Indium Tin Oxide Treated by KMnO4 Solution as Anode

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Chinese Physics Letters 2005年第3期22卷 727-729页

作者：王静路林姜文龙张颖芳赵毅侯晶莹刘式墉 NationalLaboratoryofIntegratedOptoelectronics JilinUniversityChangchun130023//DepartmentofElectronicInformationandEngineeringJilinNormalUniversitySiping136000 NationalLaboratoryofIntegratedOptoelectronics JilinUniversityChangchun130023

High-efficient organic light-emitting diodes (OLEDs) with indium-tin-oxide (ITO) anode treated by KMnO4 solution are demonstrated. The performance of the OLEDs depends on the concentration of KMnO4 solution and time of ultrasonic treatment. The OLED whose ITO anode was treated by ultrasonic in KMnO4 solution with concentration of 50mg/L for 15min displays the best performance. It has higher electroluminescent brightness and lower turn-on voltage than those of traditional devices. In particular, its efficiency can be increased by approximately 40%. The surfaces of the ITO anode with and without treating are analysed by scanning electron microscopy.

关键词： High-Efficient Organic Light-Emitting Diodes Indium Tin Oxide Treated KMnO_

A New Method to Prepare Boron Nitride Thin Films

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Chinese Physics Letters 2005年第5期22卷 1205-1206页

作者：刘立华李英爱冯伟李卫青赵春红王玉新赵永年 NationalKeyLaboratoryofSuperhardMaterials JilinUniversityChangchun130012//CollegeofPhysicsJilinNormalUniversitySiping136000 NationalKeyLaboratoryofSuperhardMaterials JilinUniversityChangchun130012

We report a new method to prepare boron nitride (BN) thin films on Si (100) substrates in an Ar–N2-BCl3-H2 gas system by magnetron arc enhanced plasma chemical vapour deposition. Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) are used to characterize the films. The FTIR spectra show that the deposited boron nitride films experienced a transition from pure h-BN phase to a cubic-containing phase with the variation of arc current ranging from 10A to 18A. The BN film with 42% c-BN was obtained without substrate bias voltage. In the gas system of Ar–N2–BCl3–H2, h-BN can be preferentially etched by chlorine. The chemical etching effect of chlorine allows the formation of c-BN without substrate bias voltage, which may develop a new perspective for the deposition of high quality c-BN film with low stress.

关键词： Chlorine

Effects of AlN Layer and Impurities on Optical Properties of GaN

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Chemical Research in Chinese Universities 2005年第1期21卷 78-82页

作者： YANGJing-hai GONGJie YANGLi-li FANHou-gang ZHANGYong-jun O.Zseboek CHENGang TheInstituteofCondensedStatePhysics JilinNormalUniversitySiping136000P.R.China／／CollegeofMaterialsScienceandEngineeringJilinUniversityChangchun130023P.R.China TheInstituteofCondensedStatePhysics JilinNormalUniversitySiping136000P.R.China DepartmentofPhysics ChalmersUniversityofTechnologyGoeteborgSE-41296Sweden CollegeofMaterialsScienceandEngineering JilinUniversityChangchun130023P.R.China

The effects of the incorporated oxygen and the different buffer layers on the optical properties and surface morphology of GaN were studied. The results show that the decrease of the concentration of the incorporated oxygen has no effect on the surface morphology, but improves the optical properties. While the introduction of the AlN buffer layer makes not only the surface morphology but also the optical properties improve. Both the oxygen contamination from the nitrogen source and the resulted morphology are directly related to the line width of the low-temperature photoluminescence(PL) spectra.

关键词： GaN Molecular beam epitaxy Photoluminescence Morphology

Structure and Luminescence Characteristics of Europium Activated Strontium Silicates Sr(Eu,Bi)SiO_3 and Sr(Eu,Bi)_2SiO_4

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Chemical Research in Chinese Universities 2003年第4期19卷 450-453页

作者： YANGJing-hai GONGJie FANHou-gang ZHANGYong-jun YANGLi-li CHENGang TheInstituteofCondensedStatePhysics JilinNormalUniversitySiping136000P.R.China CollegeofMaterialsScienceandEngineering JilinUniversityChangchun130023P.R.China

Sr2SiO4∶Eu 3+ ,Bi 3+ and SrSiO 3∶Eu 3+ ,Bi 3+ samples were synthesized at high temperature and high pressure. The effect of high pressure on the structure and luminescence properties of the samples were studied. As a comparison, the samples were also prepared by the method of sol-gel at high temperature and atmospheric pressure. The SrSiO 3∶Eu 3+ ,Bi 3+ prepared at atmosphere has a hexagonal phase structure; in the pressure range of 2 34-4 10 GPa, it is transformed into a pseudo-orthorhombic structure(monoclinic), and in the pressure range of 4 10-4 15 GPa, the structure change of Sr 2SiO 4∶Eu 3+ , Bi 3+ has not been observed, it maintains the monoclinic structure of the samples synthesized at an atmospheric pressure. High pressure makes the luminescence properties of the samples changed obviously. The intensity and the relative quantum luminescent efficiency decrease, the half-width increases obviously and the red shift occurs. The changes of the luminescence properties result from the pressure-induced changes of the crystal structures.

关键词： High pressure and high temperature Activator Luminescence characteristics

Effect of Cooling Rate on Structure and Properties of Wear-Resistant Low Chromium Cast Iron after Hot Deformation

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Journal of Iron and Steel Research(International) 2005年第2期12卷 52-55,63页

作者： CHANGLi-min WANGHai-yan HUANGYa-dian XUHong ZHOUXiao-guang jilinnormaluniversity Siping136000China YanshanUniversity Qinhuangdao066004China SipingInstituteofScienceandTechnology Siping13600China

The effect of cooling rate on structure and properties of wear-resistant low chromium cast iron after 40% hot deformation was investigated by metallographic and scanning electron microscope. The results show that the cooling rate is closely related to the structure and properties, and for the cast iron, the best comprehensive mechanical properties were obtained by forced air cooling with a cooling rate as about 7 ℃/s. The reason and regularity for the change of mechanical properties were analyzed.

关键词： cooling rate hot deformation structure property wear resistance low chromium cast iron

Entropy,Periodicity,and Graphs with Zero Euler Characteristic

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Acta Mathematica Sinica,English Series 2004年第3期20卷 415-422页

作者： JieLU JinChengXIONG JianCHEN DepartmentofMathematics SouthChinaNormalUniversityGuangzhou510631P.R.China DepartmentofMathematics JilinNormalUniversitySiping136000P.R.China

Let G be a graph which contains exactly one simple closed curve.We prove that a continuous map f:G→G has zero topological entropy if and only if there exist at most k■[(Edg(G)+End(G)+ 3)/2]different odd numbers n_1,...,n_k such that Per(f)is contained in ∪_i^k=1 ∪_j~∞=0 n_i2~j,where Edg(G) is the number of edges of G and End(G)is the number of end points of G.

关键词： Graph Topological entropy Inverse limit Period