Advanced Materials Research Vols. 941-944

Abstract: In this paper, a new CuI complex containing the bis[2-(diphenylphosphino)phenyl]ether and 7,10-Dimethyl Pyrazino [2,3-f][1,10]phenanthroline have been syntheized and characterized by 1H NMR successfully. Experimental data confirm that Complex [Cu(dppl)(DPEphos)](PF6) is high-energy-emitting one. The broad band emission upon excitation at λ = 420 nm with the emission maximum locates at λ = 577 nm was observed. The introduction of DPEphos system leads to red shift of emissive about 11 nm than complex [Cu(dppl)2](PF6). This makes them potential candidates as cheap emitting materials.

Abstract: The manufacture technology and mould structure of bonded NdFeB arc-magnets from press molding were described. The effects of the content of binder and additives, particle size of magnetic powder, the molding pressure, the treatment of magnet surface on the mechanical property, processing property, magnetic property and anti-oxidation property of press molding magnets were investigated. The press molding bonded magnets were prepared by using the MQP-B rapidly quenching NdFeB magnetic powder and epoxy binder. The magnetic properties are: Br = 0.722 T, Hcb = 457 kA/m, Hci = 718 kA/m, and (BH) max = 83.5 kJ/m³.

Abstract: The electron avalanche domains (EAD) in high gain semi-insulating (SI) GaAs photoconductive semiconductor switches (PCSS) are analyzed. The EAD are closely related to the growing domains associated with carrier injection. The EAD formation requires high carrier density and high field impact ionization. The avalanche carrier generation in the EAD can cause and complete the localized direct transform from the N-shaped current-voltage (I-V) characteristics to S-shaped I-V characteristics. Then a transition from the EAD to current filament mechanisms can occur. The EAD ideas can explain the branch and the bend of the filaments during the formation and propagation of the filaments.

Abstract: In this paper, the performance comparison between glass ceramics (Zerodur) and silicon carbide (SiC) which are two kinds of common materials used for space optical reflector is carried out, and several lightweight structure forms are analyzed. The oval plane reflector is applied in ultra-low temperature environment of space, take this kind of reflector as an example, its lightweight structure is optimized by CAD, then through finite element analysis, deformation of the planar lightweight mirror is 0.014λ (rms) in gravity condition, and deformation is 0.002λ (rms) in ultra-low temperature of-150 degrees environment. The actual lightweight processing is controled by the CNC system in a graphical way, and using chemical method to eliminate the stress and micro crack generated during processing, its final surface shape precision reaches 0.022λ (rms). Finally, this paper introduces the manufacture method of novel silicon carbide (SiC), and analyzes the current situation and development trends of the spatial lightweight reflector manufacturing technology.

Abstract: A photoelectrochemical (PEC) cell was made by a conventional three-electrode system. The working electrode was an as-prepared PbS/ITO/glass composite by a chemical bath deposition (CBD) method. The as-deposited films were characterized for structural, morphological, compositional and PEC properties. The X-ray diffraction (XRD) studies reveal that the films are polycrystalline in nature with cubic phases. The surface morphology was determined by scanning electron microscope (SEM) measurements. The film shows p-type conduction mechanism. The PEC cell, with PbS/ITO/glass as a photo cathode and Na₂SO₄ (0.10 M) solution as an electrolyte, was constructed and investigated for various cell parameters.

Abstract: The density distribution characteristics of non-equilibrium carrier from spontaneous emission ahead of the tip of the current filaments in high gain semi-insulating GaAs photoconductive semiconductor switches are analyzed. The results show that the ratio of volume to area of the current filament and the average carrier density in the current filaments are two key factors that affect the photoionization effects of the current filaments. The reabsorption of wavelengths λ ≤ 876 nm radiations plays a dominant role in producing the maximum carrier density. The maximum density of photo-generated carrier is approximately 1~3 orders of magnitude lower than the average density of excess carrier inside the current filaments.

Abstract: This research adopts comprehensive evaluation to evaluate lifetime of LED light source for lighting system. By the method, under the condition of LED light source working outside, the situations of LED light source lifetime are analyzed with attenuation rate of illumination got from illumination data of LED light source in practical work. The real lifetime characteristics and real life curve of the LED light source are obtained eventually.

Abstract: A novel electron donor unit based on phenothiazine has been designed and constructed. The target compound 10-octyl-3,7-di (thiophen-2-yl)-10H-phenothiazine was easily synthesized in high yields with a milder and efficient route via the Suzuki coupling reaction. Optical spectra show that, from the solution to the solid state, both the absorption and fluorescence spectra of the target compound are small blue-shifted. Moreover, the fluorescence spectra exhibit the emission maxima of the target compound ranging from 485 nm to 496 nm, which belongs to blue-green light range. As expected, the target compound should be a promising donor to construct D-A type materials for applications in organic light-emitting diodes (OLEDs).

Abstract: The phosphors Ca₃(BO₃)₂: Ce³⁺, Ca₃(BO₃)₂: Tb³⁺ and Ca₃(BO₃)₂: Ce³⁺, Tb³⁺ were synthesized by the solid-state reaction method at high temperature. The phase purity was characterized by the powder x-ray diffraction (XRD). The luminescence properties were investigated by ultraviolet (UV)-Vis spectra. For the phosphor Ca₃(BO₃)₂: Ce³⁺, the lowest 5d levels, the emission and the Stokes shifts of Ce³⁺ in the host lattice are identified. For the phosphor Ca₃(BO₃)₂: Tb³⁺, the f-d transitions of Tb³⁺ in the host lattice are assigned and discussed. Moreover, the energy transfer phenomenon between Ce³⁺ and Tb³⁺ in Ca₃(BO₃)₂: Ce³⁺, Tb³⁺ has been discussed. The emission of Tb³⁺ is remarkably enhanced due to energy transfer from Ce³⁺ to Tb³⁺ when Ce³⁺, Tb³⁺ doped together in Ca₃(BO₃)₂.

Abstract: 6.5wt%Si electrical steel has a wide application in electrical and electronic devices based on its excellent soft magnetic properties. However, it is very hard to prepare thin sheets of this material by conventional rolling methods, because of its obvious brittleness at room temperature. In order to avoid brittleness at high silicon content, different technological development of preparations of 6.5wt%Si electrical steel are illustrated in this work.