Advanced Materials Research Vols. 311-313

Abstract: Knowledge based plastic mold cavity design and manufacturing system is presented. The system architecture is composed of user interface, application sub-system, feature technology, knowledge database and inference engine. The feature technology applied in this system includes feature recognition and feature matching which transforms the geometric model to feature model, and feature mapping which transforms product features into mold cavity features. Knowledge database and inference engine are critical for the knowledge based system. In this system, the knowledge database is divided into rule library and case library and the inference engine is integrated with Rule Based Reasoning (RBR) and Case Based Reasoning (CBR). The result shows that it can effectively integrate the information in the cavity design and manufacturing process and promote the mold design development.

Abstract: ZnMgO films were prepared at room temperature on freestanding diamond (FSD) substrates with and without ZnO buffer layers by radio-frequency (RF) reactive magnetron sputtering method. The effects of annealing treatment and ZnO buffer layers on the structural, optical, and electrical properties of the ZnMgO films were studied by X-ray diffraction (XRD), UV-visible spectrophotometer, and electrical measurements. The experimental results suggested that the annealing treatment and buffer layer were helpful to improve the crystalline quality of ZnMgO/diamond heteroepitaxial films.

Abstract: The Cd_1-xMn_xTe crystal is believed to be a good candidate to compete with Cd_1-xMn_xTe in the X-ray and γ-ray detector application. In this paper, Indium (In) doped Cd_0.8Mn_0.2Te (CdMnTe) ingots were grown by the modified Vertical Bridgman method. The as-grown crystals were characterized using Near-Infrared (NIR) transmission spectrum mapping of composition, X-ray double-crystal rocking curve measurement, I-V measurement and ²⁴¹Am gamma rays radiation measurement. The Mn composition extracted from the NIR spectra at different axial and radial distances of the 30×40×2 mm³ CdMnTe wafers shown that the Mn concentration in the range of 0.19430.0008 to 0.2020.0025 mole fraction. The FWHM values of the X-ray rocking curves are of 40-80 arc sec, indicating a high crystalline perfection. The resistivity of the wafers is (2-3) ×10¹⁰Ω.cm. The CdMnTe planar detector irradiated by ²⁴¹Am source shows the energy resolution of 8.5%.

Abstract: Because petroleum contaminants have a big impact on marine environment, the recognition and monitoring research of petroleum contaminants has important application value. According to the petroleum products all process strong fluorescence characteristics, three-dimensional fluorescence spectroscopy technology can be applied to petroleum contaminants for monitoring. This paper adopts PARAFAC to deal with 3-d fluorescence data of petroleum pollutant. Thereby get that PARAFAC algorithm can get accurate resolution system of the corresponding spectrum each substance and relative concentrations. In addition, to get better predicted results by PARAFAC method, the fluorescence intensity of interference substance should be significantly less than fluorescence intensity of the lowest concentration of the sample which is to be predicted.

Abstract: Inverse opal photonic crystals of Eu³⁺ doped LaPO₄ (LaPO₄: Eu）were prepared by a self-assembly technique in combination with a sol-gel method. In the preparation process, Eu³⁺ doped LaPO₄ precursors were filled into the interstices of the opal template assembled by monodispersive polystyrene microspheres. The polystyrene template was then removed by calcination at 650 °C for 5h, meanwhile, Eu³⁺doped LaPO₄ inverse opal photonic crystal was formed. The photoluminescence (PL) from Eu³⁺ doped LaPO₄ inverse opal photonic crystal was studied. The effect of the photonic stop-band on the spontaneous emission of Eu³⁺ has been observed in the inverse opal photonic crystals of Eu³⁺ doped LaPO₄. Significant suppression of the emission was detected if the photonic band-gap overlaps with the Eu³⁺ ions emission band.

Abstract: A novel blue phosphor based on phosphate host matrix, MgAl(PO₄)O doped with Eu²⁺ was prepared by solid state reaction. The phosphor invariably emits blue luminescence with a peak wavelength at around 450 nm under ultraviolet excitation. The excitation spectrum showed that the phosphor can be efficiently excited by UV-visible light from 250 nm to 420 nm, which is coupled well with the emission of UV LED (350-410 nm). The results indicated that this novel phosphor may become the candidate of blue radiation-converting phosphor for white light emitting diodes in the further.

Abstract: Upconversion (UC) luminescence photonic band gap materials Tb³⁺-Yb³⁺ co-doped phosphate inverse opal photonic crystals were prepared by a self-assembly technique in combination with a sol-gel method. The effect of photonic band gap on UC luminescence was investigated in inverse opals. Effective suppression of the UC luminescence was inspected if the photonic band gap overlapped with the emission band of Tb³⁺ ions.

Abstract: Temperature characteristics are essential to reasonable application of Ni-Mn-Ga alloy. This paper reports an experiment equipment which is used as the research of variable temperature effect. The relationship between deformation rate and temperature is studied. Dynamic and static experiments are done. The results show that critical temperature is around 40°C. It can be predicted that thermo-elasticity and magnetically-controlled characteristics will disappear with the increase of temperature.

Abstract: Polycrystalline α-HgI₂ films have been grown through combining vertical deposition method with hot wall vapor phase deposition (HWPVD) method. The influence of the α-HgI₂ seed layers on the structural and electrical properties of the polycrystalline α-HgI₂ films was investigated. It is found that the α-HgI₂ seed layers play an important role in reducing the grain sizes, increasing the density improving the crystallographic orientation and electrical properties of the polycrystalline α-HgI₂ films.

Abstract: The phase structures and the magnetic properties of HDDR magnet powders produced from the alloys with a nominal composition of Nd₁₄Fe_balCo₁₄B_6.5AlxZry (x=0, ~0.35; y= 0, ~0.35) have been studied. The variation of the magnetic properties of the bonded magnets with HD temperature and DR temperature was investigated. A scruple addition of Al is useful to improve the magnetic properties of HDDR bonded magnets. And the composite addition of a little Al and Zr can further enhance the magnetic properties. As x = 0.15 and y = 0.1, the magnet properties can reach _iH_c = 990 kA/m, Br = 0.86 T and (BH)max = 118.4kJ/m³. The reasons for the enhancement of the magnetic properties by the composite addition of a little Al and Zr are analyzed.