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排序方式: 共有292条查询结果,搜索用时 15 毫秒
1.
A strongly electron deficient and high triplet energy host for blue emitters was developed by decorating a dibenzofuran modified biphenyl backbone structure with multiple CN units. Two hosts, 6,6′-bis(6-cyanodibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-3,3′-dicarbonitrile(CNDBF1) and 2,2′-bis(6-cyanodibenzo[b,d]furan-4-yl)-[1,1′-biphenyl]-4,4′-dicarbonitrile(CNDBF2), were derived from the CN decoration strategy for application in blue organic light-emitting diodes requiring high triplet energy host. They showed high triplet energy above 2.79 eV and acted as the electron transport type host based on the strong electron deficiency. The mixture of the CNDBF1 and CNDBF2 hosts with a hole transport type 3,3′-di(9H-carbazol-9-yl)-1,1′-biphenyl host performed as the exciplex host of a blue phosphor and accomplished high external quantum efficiency of 22.7% in the blue phosphorescent organic light-emitting diodes. 相似文献
2.
Abhijit Majumdar Puneet Mishra Jürgen Meichsner 《Surface & coatings technology》2007,201(14):6437-6444
Carbon nitride films have been deposited by dielectric barrier discharge with a CH4/N2 gas mixture at different conditions. Fourier Transform Infrared (FTIR) spectroscopy, X-ray photo electron spectroscopy (XPS), Raman spectroscopy, Atomic force microscopy (AFM) and ellipsometry were used to systematically study chemical composition, bond structure and surface morphology of deposited films. Various bonds between carbon, nitrogen, hydrogen, and also oxygen were observed. 相似文献
3.
通过超声辅助NaBH4还原法制备了3%Ru/CN催化剂(Ru的质量分数),该催化剂用于对苯二甲酸二甲酯(DMT)加氢制备1,4-环己烷二甲酸二甲酯(DMCD)。采用Raman、SEM、TEM、N2吸脱附、XRD、XPS等对载体和催化剂的组成、表面性质进行表征,结果表明,氮元素成功掺入碳骨架中且氮掺杂碳材料为介孔结构。研究了催化剂的用量、反应温度、H2 压力、反应时间等对催化剂加氢性能的影响。结果表明,当反应物用量为1.00 g,催化剂(含载体)用量为0.05 g,反应温度140 ℃,反应压力5.0 MPa,反应时间1 h时,DMT转化率为100%,DMCD选择性为99.3%。3%Ru/CN-1000催化剂循环使用5次后,催化剂催化性能未见明显下降,DMT转化率为98.8%,DMCD选择性为99.7%。 相似文献
4.
The popular Natural Resources Conservation Service Curve Number (NRCS-CN) (earlier known as Soil Conservation Service Curve Number (SCS-CN) method of rainfall-runoff modeling has often faced the criticism of exhibiting quantum jumps in runoff computations because of the sudden jumps appearing in CN-values derived from NEH-4 tables for three antecedent moisture conditions (AMC), viz., AMC-I, AMC-II, and AMC-III valid for dry, normal, and wet conditions, respectively. The variability of antecedent soil moisture within an AMC category is responsible for the abrupt jump and other deficiencies in the CN method for runoff estimation. This paper suggests a novel procedure to account for the antecedent moisture (M), preventing quantum jumps and eliminating deficiencies in determination of CN and, in turn, estimation of direct runoff. Its validity was verified utilizing the observed rainfall (P)-runoff (Q) events from 36 US watersheds, four sub-catchments of the Godavari basin, and small agricultural plots at Roorkee, India. The performance of the proposed model (M5) for runoff prediction was compared with the existing NRCS-CN (M1), Mishra and Singh (2002) (M2), Singh et al. (2015) (M3), and Verma et al. (2021) (M4) model using various performance indices. Using the CNs derived from observed events, model M5 was seen to have performed better than M1-M4 in terms of Nash Sutcliffe Efficiency (NSE), Root Mean Square Error (RMSE), and Percent Bias (PBIAS) for the data of US watersheds, and CN-P correlation improved as the coefficient of determination (R2) enhanced. Similarly, using the RS & GIS-based CNs on natural watersheds of the Godavari basin and considering AMC-I, the performance of M5 was again better than M1-M4 in terms of RMSE, Mean Bias Error (mBIAS), Mean Absolute Error (MAE), and Normalized-Nash Sutcliffe Efficiency (NNSE). Interestingly, there existed a significant (p < 0.05) relationship between the in-situ water content (w) measured for the experimental plots of Roorkee and the model input variable antecedent moisture (M), offering a physical touch to the conceptual model. 相似文献
5.
A water-in-oil (W/O) microemulsion composed of Triton X-100, n-hexanol, n-hexane and water solution with hydrochloric acid was prepared. K3Fe(CN)6 was added in as a water-soluble electroactive probe, and its electrochemical behavior was investigated by cyclic voltammetry
(CV) and electrochemical impedance spectroscopy (EIS). It is found that the H+ concentration of the water phase has a great effect on the conductivity of the W/O microemulsion, and hence influences the
electrochemical behavior of K3Fe(CN)6. When the pH value of water phase is about 7, the electrical conductivity of the W/O microemulsion is only 1.2×10−6 S/cm, and K3Fe(CN)6 almost cannot react at the glassy carbon electrode. But when the H+ concentration is more than 3 mol/L, the W/O microemulsion has a good electrical conductivity and K3Fe(CN)6 shows good electrochemical performance in it. The results of CV and EIS studies indicate that the electrochemical behavior
of Fe(CN)6
3−/Fe(CN)6
4− in the W/O microemulsion is different from that in the aqueous solution. This may be due to the unique liquid structure of
the W/O microemulsion and the unique mass transfer in the W/O microemulsion.
Foundation item: Projects(20673036, J0830415) supported by the National Natural Science Foundation of China; Projects(05JT1026, 2007JT2013)
supported by the Science Technology Project of Hunan Province, China 相似文献
6.
多模板尺度自适应核相关滤波器(KCF_MTSA)跟踪算法在目标移动模糊、旋转和尺度变化时跟踪距离精度与成功率较低。针对该问题,提出一种结合多特征和尺度估计的改进KCF_MTSA目标跟踪算法。采用方向梯度直方图和颜色名两种特征对目标进行表征,在训练阶段分别使用多模板核相关滤波器对上述特征进行训练,同时在检测阶段将两个滤波器的响应以权重形式进行自适应融合获取响应图实现目标定位,并使用一维相关滤波器进行目标尺度估计。实验结果表明,该算法的跟踪距离精度和准确率较改进前KCF_MTSA算法有明显提升,其距离精度和准确率分别提高15.8%和28.5%。 相似文献
7.
PREPARATIONOFSILVERPOWDERFORCONDUCTIVEPASTEChai,Liyuan;Zhong,Haiyun;Wu,Huiyun(DepartmentofNonferrousMetallurgy,CentralSouthUn... 相似文献
8.
9.
用X-射线,电子探针及磁性测量等手段对Ti(CN)基金属陶瓷切削刀具的显微组织进行了系统分析,以瑞典山特维克同类刀具与国产刀具进行对比,发现国产刀具中Co-Ni粘结相中出现了无磁性的Ni3TiC相,从而降低了材料的磁饱和、矫顽磁力及抗弯强度。Ni3TiC的出现与烧结气氛有关,是烧结时材料脱碳的结果。文章对材料中的硬质相、粘结相等进行了微区成份定量分析,确认了各元素的分配状况。对于轻元素氮的分市则采用了X-射线波谱仪对刀具断面进行扫描,发现与国外名牌产品相比,国产刀具中氮的分布欠均匀。 相似文献
10.
碳含量对Ti(CN)基金属陶瓷力学性能的影响 总被引:1,自引:0,他引:1
研究了Ti(CN)基金属陶瓷的碳含量对其物理力学性能的影响。结果表明 ,在一定范围内 ,随着碳含量的减少 ,Ti(CN)基金属陶瓷的矫顽磁力、钴磁和硬度降低 ;而抗弯强度则明显增高。 相似文献