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A novel ancillary ligand(2-(1-hydroxy-naphthyl)-benzothiozolato)(HNBT) and the corresponding red emitting phosphorescent iridium(Ⅲ) complex,Ir(ppy)2(NBT) with 2-phenylphridine(ppy) as first ligand are designed and synthesized.Saturated red-emitting electrophosphorescent devices using Ir(ppy)2(NBT) as emission center are fabricated.The thermal,photophysical,and electroluminescent properties of Ir(ppy)2(NBT) are investigated in detail.It is noteworthy that the emission spectrum shape of complex Ir(ppy)2(NBT) is similar to Gauss,which has only one emission peak centralized 614 nm with a full-width at half-maximum of 65 nm.The optimized device exhibits a maximum brightness of 6 400 cd/m2 and the peak current efficiency is 4.53 cd/A.

Using grand canonical Monte Carlo (GCMC) simulations, the physisorptions of hydrogen storage in single-walled boron–nitride nanotubes (SWBNNTs) and single-walled carbon nanotubes (SWCNTs) are studied. The influences of nanotube diameter, temperature and chirality on physisorption amounts of hydrogen in SWBNNTs and SWCNTs are mainly investigated comparatively. The results show that, (1) only trivial difference in hydrogen adsorption in SWBNNTs and SWCNTs is observed at room temperature and the physisorption amount of the former is slightly higher than that of the latter. However, the hydrogen storage capacity of SWBNNTs exhibits a more and more noticeable advantage than that of SWCNTs with temperature decreasing. Some reasonable explanations are given from hydrogen storage mechanisms of nanotubes. (2) With respect to the effect of temperature, tube diameter and chirality on physisorption properties, the trend of SWBNNTs is the same as that of SWCNTs.

This paper studies full vibrational spectra {Ev} and molecular dissociation energies De by using conventional least-squares (LS) fitting and an algebraic method (AM) proposed recently for 10 diatomic electronic states of 7Li2, Na2, NaK and NaLi molecules based on some known experimental vibrational energies in a subset [Evexpt] respectively. Studies show that: (1) although both the full AM spectrum {EvAM} and the LS spectrum {EvLS} can reproduce the known experimental energies in [Evexpt], the {EvAM} is superior to the {EvLS} in that the high-lying AM vibrational energies which may not be available experimentally have better or much better accuracy than those LS counterparts in {EvLS}, and so is the AM dissociation energy DeAM; (2) the main source of the errors in the data obtained by using the LS fitting is that the fitting which is just a pure mathematical process does not use any physical criteria that must be satisfied by the full vibrational spectrum, while the AM method does. This study suggests that when fitting or solving a physical equation using a set of source data, it is important not only to apply a proper mathematical tool, but also to use correct physical criteria which measure the physical properties of the data, kick out those data having bigger errors, and impose conditional convergence on the numerical process.

Hydrogen storage remains one of the main challenges in the implementation of a hydrogen-based energy economy. Among various porous materials, hydrogen storage in covalent-organic frameworks (COFs) has attracted the most significant attention since they were first synthesized due to good stability, large surface area, porosity and extremely low density. Although COFs exhibit promising hydrogen storage properties at very low temperatures, their hydrogen storage capacity is not satisfactory at room temperature, which is too low to meet the uptake target set by US-DOE, thereby being unable to have practical applications. Remarkably, hydrogen spillover has been experimentally demonstrated as an effective approach to improving the hydrogen storage capacity on porous materials at ambient temperature. In some of the most promising results the metal-organic frameworks (MOFs) and COFs have been used as substrates. However, the structures of many COFs materials are quite complex and the experimental condition is difficult to control. Furthermore, the sample preparations for these hydrogen spillover experiments are also very difficult. Therefore, only COF-1 is used in experimental study of hydrogen spillover. Although some theoretical work has contributed to understanding the hydrogen spillover mechanism of COFs, many basic problems about hydrogen spillover have not been solved, which hinders its practical application to a large extent. Based on the above reasons, the hydrogen spillover mechanism of Pd doped COF-108 is studied by using density functional theory (DFT) method, which mainly includes the various deposited configurations of Pd4 cluster on COF-108, the adsorption and dissociation of H2 on Pd4 cluster of Pd4@COF-108, the migration of H atom from Pd4 cluster toward the COF-108 and the diffusion of H atom on COF-108 surface. The results show as follows. 1) The larger the number of Pd atoms interacting with HHTP or TBPM cluster, the greater the binding energy of Pd4 deposited on them is. Deposited configuration orientation has little effect on binding energy. The binding energies of all deposition configurations for TBPM cluster are larger than those for HHTP cluster, so Pd4 cluster prefers to deposit on TBPM cluster with face-contact configuration. (2) H2 molecules spontaneously dissociated into Pd4 cluster, i.e., a barrierless H2 dissociation process takes place, which meets the first condition required by hydrogen spillover. 3) Only H atom located at the bridge site may migrate to the substrate surface, and the migration process is an endothermic reaction and less stable, which indicates that H atoms will further diffuse on the substrate surface. Although H atoms located at the top site may not migrate directly to the substrate surface, it will automatically migrate to the bridge site after the H atom on the bridge site has migrated to the substrate surface, so the migration process may proceed continuously. (4) The introduction of transition metal Pd can greatly reduce the diffusion energy barrier of H atoms on substrate surface, which makes it easier for H atoms to diffuse on substrate. These results may help us understand the microscopic mechanism of hydrogen spillover influencing the properties of hydrogen storage on COFs and provide useful guidance for targeted preparing the COFs materials with excellent hydrogen storage properties experimentally.

With the exposure of serious problems in a series of enterprise groups such as Lantian Group, Yinguangxia Group, Delong and Nanhai huaguang Group, the credit risks stand out for those commercial banks, which provide loans to these enterprise groups. Enterprise groups have complicated of organizational structure and concealed internal transactions, which mean that enterprise groups are grey systems. However, commercial banks matching credit evaluation and credit management at their developing stages lack of a whole objective technology that is suitable for management regulations and credit rating system. Based on investigation and research on persons, this paper proposes specially credit evaluation index system of group enterprises, including quantitative and qualitative indexes. It processes these indexes by principal component analysis method and entropy method based on grey relational analysis model of the credit score values of enterprises. Finally, it evaluates grey relational grade of credit risk between parent corporation and its subsidiary about Group “QiaQia”. The results of this analysis are consistent with practice.

This paper analyzes the TMN protocol completely using a formal analysis method called the Running-Mode Analysis and uncovers a number of attacks on the TMN protocol. These attacks are classified according to the detailed forms and the different intentions of the intruder. Finally, combining with the known attacks, the authors deduce that the Running-Mode Analysis can analyze the TMN protocol effectively.