Advanced Materials Research Vols. 393-395

Abstract: Ti50Fe22Ni22Sn6 amorphous alloy is prepared by mechanical alloying and spark plasma sintering. The milling is performed in a high-energy planetary ball mill. XRD shows that after milled 70h, fully amorphous powders can be obtained, under the condition of the milling speed, 300rpm, and the weighs ratio of ball to powder, 10:1. Thermal stability of the as-milled amorphous powder is determined by DSC at the heating rate of 40K/min. The glass transition Tg and the initial crystallization temperature Tx1 is 625K and 770K, respectively. The amorphous alloy powder is compacted by spark plasma sintering at the temperature of 633K, 653K, 673K, 688K and 723K under the compress of 400Mpa. From XRD, it can be seen that near the glass transition temperature, the samples sintered remain completely amorphous, and when the sintering temperature increasing, although not higher than the initial crystallization temperature, the sintered samples have begun to appear crystalline phases.

Abstract: Next generation of Geometrical Product Specifications (GPS) is the foundation of the technology standards and metrology specifications of mechanical and electric products. GPS estimation of uncertainty can make the results of verification of products reliable and can be compared globally. Flatness is an important geometrical feature of a product and has great influence to the product performance and assembly quality. The uncertainty in flatness three-dimensional measurements must be estimated according to GPS standards to assure the related functions of a product. According to t ISO/TS 14253-2, a calculation method of the uncertainty in flatness three-dimensional measurement by certain fitting method is proposed. The method was evaluated and improved according to Procedure for Uncertainty Management, which is given by next generation of GPS. The measurement process which can meet the target uncertainty was obtained at last.

Abstract: There is important significance in theory and practice to study the competitive power of the urban agglomeration on the west coast of the strait for promoting sustainable economic development of the urban agglomeration on the west coast of the strait. According to constructing evaluating index system of urban competitive power difference of the urban agglomeration on the west coast of the strait and the Grey Relational Synthetic Evaluation is adopted to evaluate and compare the competitive power of the urban agglomeration on the west coast of the strait. The study finds that the sequence of urban competitive strength of the urban agglomeration on the west coast of the strait is Fuzhou, Xiamen, Quanzhou, Zhangzhou, Ningde and Putian; And the competitive power shows imbalance difference distribution with ‘four groups’ that is Leading Group, Challenging Group, Catching-up Group and Backward Group, finally suggestions that shortening the non-equilibrium differences of urban competitive power between the four regions are put forward.

Abstract: The oxidation film was prepared by anode oxidation method on ZL101 aluminium surface, its morphologies, compositions and phases were characterized with SEM (Scanning Electron Microscope), optical profiler, EDS (Energy Disperse Spectroscopy), respectively, its friction coefficient and abrasion performance were analyzed by wear test, and its wear mechanism was discussed. The results show that the thickness of anode oxidation layer is about 35-40m, under dry friction condition, sliding friction coefficient is 0.65-0.72, the wear forms are abrasive attrition and adhesion wear, the low friction pair between furrows effect and adhesion effect improves the wear performance of anode oxidation film on ZL101 aluminum alloy surface.

Abstract: A new afterglow green phosphor of Zn₂SiO₄: Mn²⁺, Zr⁴⁺ was prepared by high temperature solid-state method. Effects of various preparation techniques on the crystal characteristics, luminescent properties and afterglow performance have been investigated systematically. The phosphor powders were further investigated by photoluminescence excitation and emission spectra (PL) and brightness meter. The results showed that the PL of Zn₂SiO₄: Mn²⁺, Zr⁴⁺ was observed in the green region due to transitions from the ⁴T_1g(G) to the ⁵A_1g(S) configuration of the Mn²⁺ ions. This phosphor showed obvious long-lasting phosphorescence that could be clearly seen with naked eyes in a dark room for more than 2h after the irradiation source has been removed. The possible mechanism of this phosphor was also investigated based on the TL measurements.

Abstract: This paper researched on Australian Eucalyptus regnans drying properties by 100°C Test Method, also researched 25mm-thick boards dried by air-kiln drying schedule. The result indicated that the species belongs to refractory wood when drying, with checks and collapse defects that develop easily. In order to improve the drying quality, we adopted the method of first air-drying the moisture content (MC) to four different ranges and then kiln-drying. The two phrase air-kiln drying schedule concluded that the drying cycle of 25mm-thick Eucalyptus regnans board from 76.34% to 13.11% MC was 33.5 days, and the drying quality of visible defect met the requirement for the first level of the Chinese national standards.

Abstract: In the paper, a novel combined image encryption and compression scheme is proposed. It performs encryption before compression. Making use of the properties of discrete wavelet transform (DWT) and Set Partitioning in Hierarchical Trees (SPIHT) coding, confusion is restricted to the interior of single subband image itself and so image details are retained. The proposed algorithm possesses a good visual quality of the reconstructed image and a high encryption speed.

Abstract: The present study investigates numerically the compressive residual strength of indented sandwich composite panel. The composite is made of carbon fiber reinforced plastic (CFRP) face sheets and aluminum honeycomb core. The sandwich is loaded under quasi-static condition and along out-of-plane direction. A commercial finite element analysis software ABAQUS is used. The results show that the indented composite retains significant amount of strength after indentation. And, the post-indentation strength of the composite is about 65% its pre-indentation strength under compression.

Abstract: An index system was set up in this paper which included two secondary indexes, external risk and internal risk, 9 third indexes and 29 fourth ones on the basis of coal enterprises’ expansion situations. The reasonable weights in this index system were calculated by analytic hierarchy process and the fuzzy comprehensive evaluation model was set up. Then the expansion risk of a coal enterprise was evaluated by this model.

Abstract: Given there is a great deal of correlation among indicators in the process of computer network security risk assessment, the handling of correlation is of great significance for the effectiveness of risk assessment. In this paper, we propose a hybrid computer network security risk model based on the analytic hierarchical process and gray relational analysis theory. At fist, the weight of each indicator will be elicited by means of analytic hierarchical process. Further, gray relational analysis theory will be used for the final evaluation, which avoids subjective estimation of experts or managers of banking. Finally, the model is further demonstrated and validated via a case study, and the result implies that the assets and vulnerability may be the most important factor for network security management.