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Electroluminescent properties of three ternary europium complexes with different phenanthroline derivatives

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Science china chemistry 2004年第4期47卷 326-334页

作者： BIAN Zuqiang1,2. GAO Deqing1, GUAN Min1, XIN Hao1, LI Fuyou1, HUANG Chunhui1, WANG Kezhi2.& JIN Linpei2.1. State Key Laboratory of Rare Earth Materials chemistry and Applications, Peking university, {2. 100871, china 2. department of chemistry, beijing normal university, beijing 100875, china State Key Laboratory of Rare Earth Materials chemistry and Applications Peking University Beijing China department of chemistry Beijing Normal University Beijing China

Three ternary Eu(III) complexes with general formula of Eu(DBM)3LN (DBM = dibenzoylmethanate, and LN (N = 1-3 ) stand for three different 1,10-phenanthroline derivatives) have been synthesized for vacuum deposition films-based electroluminescent devices. The complex Eu(DBM)3L3 (L3 = 2.phenyl-3-[3-(carbazol-9-yl)propyl]imidazo[4,5-f]1,10-phenan-throline) was designed with an effort to combine the electron-transporting phenanthroline platform and the hole-transporting carbazole group into one molecule expecting to improve both electron and hole transporting properties simultaneously. The results show that the variation of the neutral ligands in Eu(III) mixed ligand complexes is a simple and effective approach to the improvement in the thermal stability, PL and EL properties of materials. A double-layer device with the configuration of ITO/TPD (50 nm)/Eu(DBM)3L3 (50 nm)/Mg0.9Ag0.1 (2.0 nm)/Ag (100 nm) exhibited Eu(III)-based pure red emission with a maximum brightness of 561 cd/m2.at 16 V, and an onset driving voltage of 8 V. A device with the configuration of ITO/TPD (50 nm)/[Eu(DBM)3L3 (5 nm):BCP (5 nm)]4/BCP (2. nm)/AIQ (10 nm) Mg0.9Ag0.9 (110 nm)/Ag (100 nm) gave high efficient and pure red light emission with a luminance of 1419 cd/m2. Keywords dibenzoylmethane - electroluminescence - lanthanide - N ligands

关键词： dibenzoylmethane electroluminescence lanthanide N ligands

^(12.)I-4-(N-苄基哌啶基)-4-碘代苯磺酰胺的体内σ受体亲和性能研究

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同位素 2004年第4期17卷 198-203页

作者：张春丽刘巧平王荣福付占立刘伯里北京大学第一医院核医学科北京100034 北京师范大学化学系放射化学教研室北京100875

经化学合成与放射性碘取代三丁基锡法制得12.I-4-(N-苄基哌啶基)-4-碘代苯磺酰胺,并观察了其在荷不同肿瘤细胞小鼠体内的分布,以探讨12.I-4-(N-苄基哌啶基)-4-碘代苯磺酰胺的体内σ受体亲和性能及应用于σ受体阳性肿瘤导向诊断与导向治... 详细信息

经化学合成与放射性碘取代三丁基锡法制得12.I-4-(N-苄基哌啶基)-4-碘代苯磺酰胺,并观察了其在荷不同肿瘤细胞小鼠体内的分布,以探讨12.I-4-(N-苄基哌啶基)-4-碘代苯磺酰胺的体内σ受体亲和性能及应用于σ受体阳性肿瘤导向诊断与导向治疗的可能性。结果显示:12.I-4-(N-苄基哌啶基)-4-碘代苯磺酰胺在表达σ受体的脏器--肝脏、脾脏、心脏、肺脏、肾脏、小肠以及小鼠肝癌H2.与乳腺癌EAC中具有高的摄取;σ受体配体氟哌啶醇可抑制标记配体在心脏、肺脏和脾脏中的摄取,但在肿瘤EAC中的摄取未受抑制。肿瘤与脑和肌肉有较高的T／NT值,肿瘤与肌肉的T／NT值在注射后2.h最高,可达6.98。

关键词： σ受体 ^12.I-4-(N-苄基哌啶基)-4-碘代苯磺酰胺生物分布

脲衍生物型手性色谱柱拆分氨基酸对映体的研究

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烟台师范学院学报（自然科学版） 2000年第1期16卷 47-50页

作者：吕海涛邓锐孙美娟云自厚莱阳农学院基础部山东莱阳265200 北京师范大学化学系北京100875

利用脲衍生物型手性色谱柱对氨基酸对映体的拆分进行了研究 ,并对拆分机理进行了探讨 .结果表明 ,正相色谱法的手性分离效果明显优于反相色谱法 ,适宜的流动相组成的体积比为正已烷 :二氯乙烷 :乙醇 =75:1 8:7.在拆分过程中 ,起主要作... 详细信息

利用脲衍生物型手性色谱柱对氨基酸对映体的拆分进行了研究 ,并对拆分机理进行了探讨 .结果表明 ,正相色谱法的手性分离效果明显优于反相色谱法 ,适宜的流动相组成的体积比为正已烷 :二氯乙烷 :乙醇 =75:1 8:7.在拆分过程中 ,起主要作用的是固定相的 ( R) - 1 - ( α-萘基 )乙胺基部分的手性碳原子 ,另一个手性碳原子在分离过程中起辅助作用 .

关键词：液相色谱脲衍生物型手性色谱柱氨基酸对映体

Recommendation Method for Contrastive Enhancement of Neighborhood Information

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Computers, Materials & Continua 2024年第1期78卷 453-472页

作者： Hairong Wang beijing Zhou Lisi Zhang He Ma School of Computer Science and Engineering North Minzu UniversityNingxia750021China

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation ***,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge *** tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge ***,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and ***,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view *** paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge ***,this paper introduces multi-task learning to mitigate the problem of weak supervisory *** validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-2.M,Book-Crossing,and Last-FM *** results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

关键词： Contrastive learning knowledge graph recommendation method

Theoretical study on thermal decomposition of azoisobutyronitrile in ground state

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Science china chemistry 2004年第5期47卷 373-380页

作者： SUN Chengke1,2. ZHAO Hongmei1 & LI Zonghe1 1. department of chemistry,{2., beijing 100875, china 2. department of chemistry, Qujing normal College, Qujing 655000, china Dept. of Chem. Beijing Normal Univ. Beijing 100875 China Dept. of Chem. Qujing Normal Coll. Qujing 655000 China

The thermal decomposition mechanisms of azoisobutyronitrile (AIBN) in the ground state have been investigated systematically. Based on the potential energy surfaces (PES) of various possible dissociation paths obtained using the semiempirical AM1 method with partial optimization, the density function theory B3LYP/6-311G* method was employed to optimize the geometric parameters of the reactants, the intermediates, the products and the transition states, which were further confirmed by the vibrational analysis. The obtained results show that the re- action process of the two-bond (three-body) simultaneous cleavage Me2.CN)C─ N=N─ C(CN)Me2. 2.e2.CN)C?+N2.is much more favorable than the reaction process of the two one- bond asynchronous cleavage Me2.CN)CN=N─C(CN)Me2.? Me2.CN)CN=N?+ Me2.CN)C?? Me2.CN)C?+ N2. It was suggested that the electron shrinking effect of double bond (─N=N─) in AIBN and the stabilities of the Me2.CN)C?radical as well as N2.molecule are main factors of leading to the reaction proceeding in the former pathway. The calculation results were consistent with all the experimental facts.

关键词： azoisobutyronitrile, radicals, thermal decomposition, density function theory (DFT).

Progress in the study of molecular organized assemblies by dielectric relaxation spectroscopy

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Progress in Natural Science:Materials International 2006年第3期16卷 221-230页

作者： ZHAO Kongshuang, HE Kejuan and WEI Suxiang (department of chemistry,{2., beijing 100875, china department of chemistry, South china normal university, Guangzhou 510631, china) department of chemistry Beijing Normal University Beijing 100875 China department of chemistry South China Normal University Guangzhou 510631 China

Because dielectric spectroscopy covers a great many problems in physical and chemical systems occurring in an extremely wide frequency range, the study of this method plays an important role in physical chemistry. As an effective tool to detect inner properties of substance systems, the dielectric spectroscopy method is widely used in chemical systems and has been dramatically developed in recent decade. This review paper describes the applications of the dielectric spectroscopy in the chemical field, and main concentrations are focused on the micelle, microemulsion and other so-called molecular organized assemblies. Some dielectric principles and models proposed for these systems are introduced. In addition, recent technical developments in dielectric spectroscopy and developing trend of this method in other chemical systems are reviewed.

关键词： dielectric relaxation micelle microemulsion vesicle relaxation time.

SINGLE BIRTH PROCESSES

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Chinese Annals of Mathematics,Series B 1999年第1期20卷 77-82页

作者： CHEN MUFA(department of Mathematics,beijing {2. university,beijing 100875,china) department of Mathematics Beijing Normal University Beijing 100875 China

The single birth process is a Markov chain, either time-continuous or time-discrete, valuedin the non-negative integers: the system jumps with positive rate from k to k + 1 but not tok +j for all j 2.(this explains the meaning of 'single birth') . However, there is no restrictionfor the jumps from k to k - j(1 j< k). This note mainly deals with the uniqueness problemfor the time-continuous processes with an extension: the jumps from k to k + 1 may also beforbidden for at most finite number of k. In both cases (time-continuous or -discrete), thehitting probability and the first moment of the hitting time are also studied

关键词： Markov chains Single birth process Uniqueness criterion

Solvation effects on brain uptakes of isomers of ^(99m)Tc brain imaging agents

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Chinese Science Bulletin 2002年第21期47卷 1786-1791页

作者： JIA Hongmei, MA Xiaohui, WANG Cunxin & LIU Boli1. department of chemistry,{2., beijing 100875, china 2. Center for Biomedical Engineering, beijing Polytechnic university, beijing 10002., china department of chemistry Beijing Normal University Beijing 100875 China Center for Biomedical Engineering Beijing Polytechnic University Beijing 100022 China

Analysis of electrostatic hydration free energies of the isomers of the 99mTc-BAT and 99mTc-DADT complexes is carried out using the computer simulation technique. The results show that not only a correlation exists between the logarithm of the brain uptake and the electrostatic hydration free energy for the isomers of 99mTc-brain radiopharmaceu-ticals, but also a linear relationship exists between the logarithm of the ratio of the brain uptake of the syn isomer to that of the anti one and the difference between the electrostatic hydration free energy of the syn-isomer and that of the anti one. Furthermore, the investigation on the important factors influencing the brain uptakes of 99mTc-radiophar-maceuticals and the reasons of the different biodistribution of the isomers of the 99mTc-complexes is explored at the molecular level. The results may provide a reference for the rational drug design of brain imaging agents.

关键词： 99mTc-brain imaging agent isomer brain uptake electro-static hydration free energy.

Recovery of functions via their irregular sampling values

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Chinese Science Bulletin 1998年第4期43卷 268-271页

作者： FANG Gensun department of Mathematics, beijing normal university,{2., china department of Mathematics Lkijing Normal University Beijing China

It is proved that if a function can be completely reconstructed by tempered splines which satisfy the real Kiesz basis condition as the degree of spline goes to infinity, then the function is band limited.

关键词： band limited function cardinal splines irregular sampling.