PHASE COMPONENT AND CURIE TEMPERATURE OFNd_4(Fe_(1-x)Cr_x)_(77.5)B_(18.5)ALLOYS

The phase component and Curie tempemture of Nd4(Fe1-xCrx)77.5B18.5 (0 <x <0.25) alloys have been studied. X-ray diffraction analysis shows the presence of α-Fe and Fe3B phases in the samples with x < 0.1 and the presence of α-Fe, Nd2Fe14B and Fe2B phases in the samples with x > 0.1. The magnetic measurement shows that Curie temperutures of Fe3B and Nd2Fe14B phases decrease with increasing Cr content. The influence of the substitution of Cr for Fe was discussed.

Hydrocarbon Detection Based on Phase Decomposition in Chaoshan Depression, Northern South China Sea

Located in the northern South China Sea,Chaoshan Depression is mainly a residual Mesozoic depression,with a construction of Meso-Cenozoic strata over 7000m thick and good hydrocarbon accumulation conditions.Amplitude attribute of-90°phase component derived by phase decomposition is employed to detect Hydrocarbon in the zone of interest(ZOI)in Chaoshan Depression.And it is found that there are evident amplitude anomalies occurring around ZOI.Phase decomposition is applied to forward modeling results of the ZOI,and high amplitudes occur on the-90°phase component more or less when ZOI is charged with hydrocarbon,which shows that the amplitude abnormality in ZOI is probably caused by oil and gas accumulation.

Relationship between phase composition and corrosion resistance of Ni-Ti-Nb based shape memory alloys

The stability and microstructure of Ni Ti Nb based shape memory alloys were investigated after alloyed with elements Zr, Cr and V. In artificial seawater (3.5%NaCl) and physiological solution (5%NaCl+0.1%H 2O 2), the results show that the alloying elements influence the corrosion behavior of Ni Ti Nb alloys. Generally, Zr improves the corrosion resistance of Ni Ti Nb alloy, Cr reduces its corrosion resistance and V does not change the property. In order to investigate the reason of the difference,the relation of the phase components and corrosion resistance of Ni Ti Nb based shape memory alloys were studied by element analysis and SEM.

X-ray diffraction study of effect of deposition conditions on α-β phase transition and stress evolution in sputter-deposited W coatings

Pure W and W-Cu-W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The α-β phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray diffraction. They are directly related to the film microstructure, density and adhesion. Therefore, control of the film stress and phase component transition is essential for its applications. The phase component transition from β-W to α-W and intragranular stress evolution from tensile to compressive strongly depend on the deposition parameters and can be induced by lowering Ar pressure and rising target power. The compressively stressed films with α-W phase have a dense microstructure and high adhesion to Fe substrate.

Comparison of Concrete Carbonation Process under Natural Condition and High CO_2 Concentration Environments

To compare the results obtained under both natural and accelerated environments,the pH values of carbonated concrete were measured,the variation of pH values was determined,and the variations of Ca（OH）2 and CaCO3 contents in the carbonated concrete under natural condition and high CO2 concentration accelerated climate environments were determined by microcosmic test methods such as DTA and X-ray diffraction.The experimental results showed that the overall variation trend of pH values and phase component of carbonation layer of concrete under accelerated climate environments with high CO2 concentrations were the same as those under natural conditions.Therefore,the carbonation processes of concrete were considered consistent under both conditions.However there was a difference in the length of semi-carbonation zones.The one measured under high CO2 concentration accelerated climate environments was shorter than that under natural condition.Experimental investigation showed that it was caused by the differences in climate condition（temperature and relative humidity） as well as the properties of the concrete.The concentration of CO2 and the duration of the carbonation process have no effect on the length of semi-carbonation zone.Thus,it is acceptable to simulate the natural condition by applying the high CO2 concentration artificial accelerated carbonation technique for the purpose of the study of carbonation process of concrete.

Fingerprint Liveness Detection Based on Multi-Scale LPQ and PCA

Fingerprint authentication system is used to verify users' identification according to the characteristics of their fingerprints.However,this system has some security and privacy problems.For example,some artificial fingerprints can trick the fingerprint authentication system and access information using real users' identification.Therefore,a fingerprint liveness detection algorithm needs to be designed to prevent illegal users from accessing privacy information.In this paper,a new software-based liveness detection approach using multi-scale local phase quantity(LPQ) and principal component analysis(PCA) is proposed.The feature vectors of a fingerprint are constructed through multi-scale LPQ.PCA technology is also introduced to reduce the dimensionality of the feature vectors and gain more effective features.Finally,a training model is gained using support vector machine classifier,and the liveness of a fingerprint is detected on the basis of the training model.Experimental results demonstrate that our proposed method can detect the liveness of users' fingerprints and achieve high recognition accuracy.This study also confirms that multi-resolution analysis is a useful method for texture feature extraction during fingerprint liveness detection.

Science and technology in high-entropy alloys

As human improve their ability to fabricate materials, alloys have evolved from simple to complex compositions, accordingly improving functions and performances,promoting the advancements of human civilization. In recent years, high-entropy alloys（HEAs） have attracted tremendous attention in various fields. With multiple principal components, they inherently possess unique microstructures and many impressive properties, such as high strength and hardness, excellent corrosion resistance, thermal stability, fatigue,fracture, and irradiation resistance, in terms of which they overwhelm the traditional alloys. All these properties have endowed HEAs with many promising potential applications.An in-depth understanding of the essence of HEAs is important to further developing numerous HEAs with better properties and performance in the future. In this paper, we review the recent development of HEAs, and summarize their preparation methods, composition design, phase formation and microstructures, various properties, and modeling and simulation calculations. In addition, the future trends and prospects of HEAs are put forward.