[en] The nonlinear optical properties of Β-BaB/sub 2/O/sub 4/ (beta barium borate) are demonstrated in the generation of second through fifth harmonics of 1.06-μm neodymium laser radiation and in optical parametric oscillation pumped by 532-nm radiation. Β-BaB/sub 2/O/sub 4/ is particularly useful for high average power applications and nonlinear frequency generation in the ultraviolet to wavelengths as short as 200 nm. An internal energy conversion efficiency of 84% for 1064-nm to 532-nm second harmonic generation, and cascaded harmonic conversion to the 213-nm fifth harmonic with 11% overall conversion were obtained. The observed performance agrees well with that predicted by modeling

[en] A patterned array of diamond-like carbon (DLC) was grown on anodic aluminum oxide (AAO) template by filtered cathodic arc plasma (FCAP) technique at room temperature. The diameters of patterned array of DLC were ∼150 nm, and the patterned array density was estimated to ∼10⁹ cm^-2. A broad asymmetric band ranging from 1000 cm^-1 to 2000 cm^-1 was detected by Raman spectrum attributed to characteristic band of DLC. The fraction of sp³ bonded carbon atoms of the patterned array of DLC was measured by X-ray photoelectron spectrum (XPS) and the ratio was about 62.4%. Field emission properties of the patterned array of DLC were investigated. A low turn-on field of 3.4 V/μm at 10 μA/cm² with an emission area of 3.14 mm² was achieved. The results indicated that the electrons were emitted under both the effect of enhanced field because of the geometry and the work function of the DLC sample. Based on Fowler-Nordheim plot, the values of work function for the patterned array of DLC were estimated in range of 0.38 to 1.75 from a linearity plot

[en] Fault diagnosis and particle discrimination can be fundamentally solved as a case of pulse shape discrimination (PSD). The classical methods of PSD are inconvenient or not effective when more than two pulse shapes need to be discriminated or the pulse shapes have only small differences. A direct method to discriminate nuclear pulse shapes based on principal component analysis (PCA) and support vector machine (SVM) is reported in this paper. The training and testing accuracies of SVM classifiers with different kernels were not the same, and the algorithms were shown to have great noise immunity. Though the samples in the Group A and Group C cannot be discriminated with the naked eye, the accuracies are all above 94.7% if suitable SVM kernels are selected. There is no evidence showing that the Gaussian kernel is superior. The lower sampling frequency of the analog-to-digital converter and the information loss caused by dimension reduction were also considered.

[en] Awl-shaped diamond-like carbon (DLC) was directly grown on anodic aluminum oxide (AAO) template by using filtered cathodic arc plasma (FCAP) technique at room temperature. The awls of DLC were about 250 nm in the height and the diameters of the awls were ∼100 nm at the top. The awl density was estimated to be ∼10⁸ cm^-2. A broad asymmetric band ranging from 1100 to 1800 cm^-1 was detected by Raman spectrum. This asymmetric band was characteristic band of DLC. The sp³/(sp³+sp²) ratio of C-C bond of the awl-shaped DLC was measured by X-ray photoelectron spectrum, and it was about 68.3%. Field-emission properties of the awl-shaped DLC were investigated. A low turn-on field of 2.6 V/μm at 10 μA/cm² with an emission area of 3.14 mm² was achieved, and the emission current stability was very good. The results indicated that the electrons were emitted under both the effect of enhanced field because of the geometry and the work function of the DLC sample. Based on Fowler-Nordheim plot, the values of work function for the awl-shaped DLC were estimated in ranges of 0.23-1.08 from a linearity plot

[en] A set of Al/AlN multilayers with various modulation periods were prepared using DC magnetron sputtering method. Low angle X-ray diffraction (LAXRD) was used to analyze the layered structure of multilayers. The phase structure of the films was investigated with grazing angle X-ray diffraction (GAXRD). LAXRD results indicate that well-defined multilayer modulation structures are formed for the relatively larger modulation periods. However, the loss of mutilayered structure is detected in the multilayer with low modulation period. A very wide amorphous peak is observed in multilayer with modulation period of 4 nm. The multilayers show obvious crystallization at larger modulation periods, however, the diffraction peaks are much wider than the Al single layer because of the interruption of the continuous columnar grain growth by alternating deposition processes. Nanoindentation experiments were performed to study the mechanical properties as a function of multilayer modulation period. It is found that the hardness of the multilayers is greater than the hardness calculated from rule of mixtures. With the modulation periods adjusted, the multilayers are even harder than its hard component (AlN). A maximum hardness of 24.9 GPa, about 1.9 times larger than its hard component (AlN) and 3.7 times larger than the hardness calculated from the rule of mixtures, is found at the multilayer with modulation period of 16 nm. The wear test results show that the multilayers possess lower and stable friction coefficient, and superior wear properties

[en] Titanium aluminum nitride (TiAlN) ternary coating is a potential material which is expected to be applied on satellite for thermal controlling. In order to investigate thermal controlling property, TiAlN coatings were deposited on Si wafers with different N₂ and Ar flux ratio by reactive magnetron co-sputtering. The structure, morphology, chemical composition and optical reflectance are investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), atom force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and spectrophotometer, respectively. The orientation of the coatings depends on the N₂/Ar flux ratio. The coatings deposited with N₂/Ar ratio of 10, 30 and 60% show the cubic-TiN [2 2 0] preferred orientation and the coating deposited with N₂/Ar ratio of 100% exhibits the phase of hexagonal-AlN and cubic-TiN. The surface of the coatings becomes more compact and smoother with the N₂/Ar ratios increase. XPS spectrum indicates that the oxides (TiO₂ and Al₂O₃), oxynitride (TiN_xO_y) and nitrides (TiN and AlN_x) appear at the surface of the coatings. Ignoring internal power, the optimum equilibrium temperature of TiAlN coatings is 18 deg. C and the equilibrium temperature after heat-treated has slight change, which provides the prospective application on thermal controlling

[en] ZnO thin film has been deposited on the glass substrate at a temperature of 200 deg. C using the filtered cathodic arc plasma (FCAP) technique with the oxygen flow rate of 1.0, 3.0, 5.0, 7.0, 9.0 and 10.0 sccm. The deposition processes are only held in pure oxygen atmosphere. The as-grown films exhibit a polycrystalline hexagonal wurtzite structure. With the oxygen flow rate increase, the crystallinity of the samples first increases and then decreases as measured by X-ray diffractometry (XRD). And the tensile stress exists in all the as-grown thin films. The small grain with a mean diameter of 13 nm is observed by the field emission scanning electron microscopy (FESEM). The electrical resistivity values of the thin films are very low ranging from 5.42 x 10^-3 Ω cm to 4.0 x 10^-2 Ω cm. According to the result from room temperature photoluminescence spectra measurement, the luminescent bands also depend on the oxygen supply

[en] Nanometer scale Al/AlN multilayers have been prepared by dc magnetron sputtering technique with a columnar target. A set of Al/AlN multilayers with the Al layer thickness of 2.9 nm and the AlN layer thickness variation from 1.13 to 6.81 nm were determined. Low angle X-ray diffraction (LAXRD) was used to analyze the layered structure of multilayers. The phase structure of the coatings was investigated with grazing angle XRD (GAXRD). Mechanical properties of these multilayers were thoroughly studied using a nanoindentation and ball-on-disk micro-tribometer. It was found that the multilayer hardness and reduced modulus showed no strong dependence on the AlN layer thickness. Al2.9 nm/AlN1.13 nm multilayer had more excellent tribological properties than single layers and other proportion multilayers with a lowest friction coefficient of 0.15. And the tribological properties of all the multilayers are superior to the AlN single layer