Advanced Materials Research Vols. 1033-1034

Abstract: A kind of conductive composite yarn was designed and manufactured, then the resistance-strain characteristics of the knitted fabric based on the conductive composite yarn were tested and analyzed. The result showed that the yarn has excellent elastic deformation, better conductive performance, and good spin ability. The relationship between tensile deformation and resistance complies with contact resistance theory, the increasing of the elongation, the decreasing of the resistance. The resistance-strain curve accords with quadratic model, but the curve is linear Approximation and highly sensitive for the stresses of 0—12%. The sensitive of the curve is affected by the twist of the conductive composite yarn, the smaller the twist, the higher the sensitivity.

Abstract: A novel photodiode was fabricated for detecting the weak emission light of infrared up-conversion material. This GaAsP/GaP photodiode has a PIN structure, with the spectral response range is 500nm to 650nm, and the peak sensitivity wavelength is 555nm. The dark current is below 4nA at a bias of-5V. The response characteristics is 0.12μA/μW at a bias of-5V.

Abstract: The effects of grain sizes and oxygen impurities on thermal conductivity in aluminum nitride (AlN) ceramics has been calculated by density functional perturbation theory (DFPT) and quasi-harmonic approximation (QHA) combined with Debye theory in the paper. From 300K up to 1000K, the predicted thermal properties are compared with experimental data. The agreements with experiment suggest that the theoretical method used in the paper is an effective approach. From our theoretical study, the reduction of thermal conductivity is greater between grain sizes of 1μm and 5μm, while it’s smaller between 8μm and 10μm. Oxygen defects bring about greater influence on thermal conductivity at low temperature than at high temperature. The influence of the oxygen defect is not as significant as the grain sizes when the oxygen concentrations are less than 0.70 at. %, so it’s more important to increase the grain sizes than reduce the oxygen contents in the preparation process to achieve high thermal conductivity AlN ceramics.

Abstract: To estimate Cerenkov radiation generated in various dielectric materials, in this study, we calculated therapeutic photon beams induced electron fluxes in a CaF₂, PMMA, SiO₂ and Al₂O₃ by using the Monte Carlo N-particle Extended transport code (MCNPX). Also, we clarified the relationship between electron fluxes produced in various dielectrics and energy depositions in water by irradiation of therapeutic photon beams. The electron fluxes and the energy depositions were calculated as a function of water depth.

Abstract: Two kinds of cyanine dye were doped respectively in 4-cyano-4'-pentylbiphenyl (5CB) at a concentration ca. 1.0 wt%, and the mixture was sandwiched between two pieces of rubbed glass plates. The third-order nonlinear optical responses of cyanine dye-doped 5CB layers were measured for light polarized parallel to the oriented direction by the resonant femtosecond forward degenerate four-wave mixing technique at 820 nm. The time resolution of the system was ca. 0.3 ps. The amplified spontaneous emission spectra of cyanine dye-doped 5CB layers indicate that the decay of the slow response was accelerated with increasing laser power. The population grating disappears within ca. 5 ps.

Abstract: The metal grid transparent conductive film is a kind of important electronic material. The production method is a valuable topic. Gravure printing, as one direct-printing method, is suitable for printing the metal grid transparent conductive film, according to gravure printing principle. This paper focuses on improving gravure plate to print the metal grid transparent conductive film. Firstly, the nano-sliver grid transparent conductive film is printed by electronic engraving plate and laser ablation plate. Then, according to the analysis result that the resistivity of the nano-sliver grid transparent conductive film printed by two general plates is too high to meet the requirements of the transparent conductive film, the general plate-making methods is improved to make the new gravure plate. Last, the metal grid transparent conductive film, with relatively high light transmittance and low resistivity which meet the requirements of the transparent conductive film , is printed by the improved plate.

Abstract: As one method of producing RFID antenna, direct-printing has some advantages including simple process, low cost and less pollution. Gravure printing is suitable for printing RFID antenna, according to gravure printing principle. The whole process of gravure printing RFID antenna is researched in this paper, which includes the conductive ink, the plate-making and the determining of printing technical parameters. At last, the printed RFID antenna is packaged and measured, in order to verify the gravure printing RFID antenna can be used in practice. The measure result shows that the printed RFID antenna can totally meet the practical requirements of the RFID tag.

Abstract: The photoisomerization effect on new chalcone derivative is reported. The synthesized chalcone was characterized by different spectral analysis such as ¹H-NMR, ¹³C-NMR, FTIR, LCMS and UV/Vis. It revealed the photoisomerization effect in solution, the E-Z isomerization occurred around 60sec, whereas Z-E isomerism occurred at 0min. This chalcone derivative is more useful in fabrication of permanent optical storage devices.

Abstract: Thermal management is one of the major challenges in the development of high powered LEDs. The effects on thermal conductivity of impurity concentration and thickness are studied in Cu doped AlN (AlN:Cu) phosphor in the paper. Density functional perturbation theory (DFPT) and quasi-harmonic approximation (QHA) combined with Debye model are used in the calculation. The results show that thermal conductivity of AlN:Cu is higher than that of Nd doped ytterbium aluminum garnet (YAG:Nd) from 300K up to 1000K thus the temperature of LEDs can be controlled efficiently. Thermal conductivity increases with the rising of thickness while it decreases with the addition of Cu concentration. The influence of Cu concentration on thermal conductivity depends on temperature. The lower the temperature is, the bigger the influence.

Abstract:

Two iridium complexes, orange emitter bis[2-(9, 9-diethylfluoren-2-yl)-5-trifluoromethyl- pyridinto-C³, N] iridium (acetylacetonate) ((fl-5CF₃-py)₂Ir(acac)) and blue emitter bis(4,6-difluoro- phenylpyridine)(picolinate) iridium(III) (FIrPic), were used. As a single emitting layer at the constant emitting concentration of 8 wt %, EL spectra of the device containing the emitting layer PVK: PBD: (fl-5CF₃-py)₂Ir(acac) (8 wt %) peaked at 588 nm, the device having the emitting layer PVK: PBD: (fl-5CF₃-py)₂Ir(acac) (2 wt %): FIrPic (6 wt %) showed the main peak at 588 nm and the weak shoulder peaks at 472 and 500 nm, the device containing the emitting layer PVK: PBD: (fl-5CF₃-py)₂Ir(acac) (0.2 wt %): FIrPic (7.8 wt %) exhibited the main peak at 580 nm and slightly higher shoulder peaks at 472 and 500 nm. The device having the double emitting layers CBP: (fl-5CF₃-py)₂Ir(acac) (5 wt %) by spin-coating method and mCP: FIrPic (8 wt %) by vacuum deposition showed the main peaks at 472 and 500 nm, and shoulder peak at 580 nm. Maximum luminances of devices were found to be 14582 cd/m² (at 16 V), 12497 cd/m² (at 17 V), 1061 cd/m² (at 23 V), and 5396 cd/m² (at 25 V), respectively. The absence of host PVK, PBD, mCP or CBP emission in these devices indicated an efficient energy transfer from the host to the guest complex. Holes and electrons were efficiently recombined in the double emitting layers and an important approach for making WOLEDs was provided in the future.