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High J c Ti-doped MgB 2 disks were synthesized by two-step reaction method and high-energy ball milling. In the first step, the sample with a nominal composition of Mg 0.8 Ti 0.2 B 4 was sintered at 900 °C for 2 h. In the second step, an appropriate amount of Mg was then added to get the stoichiometry of Mg 0.9 Ti 0.1 B 2 , which was milled for 5 h and sintered at 750 °C for 2 h. The phase, microstructure and superconductivity of MgB 2 were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and superconducting quantum interference device (SQUID). The critical current density reaches 6.9 × 10 4 A cm −2 at 20 K and 1 T. The investigation showed the efficient combination between two-step reaction method and high-energy ball milling is effective to obtain high density and fine grain size bulk MgB 2 with high J c performance.

A passive and multi-channel microwave sounder onboard Chang'E-2 orbiter has successfully performed microwave observation of the lunar surface and subsurface structure. Compared with Chang'E-1 orbiter, Chang'E-2 orbiter obtained more accurate and comprehensive microwave brightness temperature data which is helpful for further research. Since there is a close relationship between microwave brightness temperature data and some related properties of the lunar regolith, such as the thickness, temperature and dielectric constant, so precise and high resolution brightness temperature is necessary for such research. However, through the detection mechanism of the microwave sounder, the brightness temperature data acquired from the microwave sounder is weighted by the antenna radiation pattern, so the data is the convolution of the antenna radiation pattern and the lunar brightness temperature. In order to obtain the real lunar brightness temperature, a deconvolution method is needed. The aim of this paper is to solve the problem in performing deconvolution of the lunar brightness temperature. In this study, we introduce the maximum entropy method(MEM) to process the brightness temperature data and achieve excellent results. The paper mainly includes the following aspects: firstly, we introduce the principle of the MEM, secondly, through a series of simulations, the MEM has been verified an efficient deconvolution method, thirdly, the MEM is used to process the Chang'E-2 microwave data and the results are significant., Comment: 13pages,13figures,Accepted for publication in RAA

Lunar Penetrating Radar (LPR) based on the time domain Ultra-Wideband (UWB) technique onboard China's Chang'e-3 (CE-3) rover, has the goal of investigating the lunar subsurface structure and detecting the depth of lunar regolith. An inhomogeneous multi-layer microwave transfer inverse-model is established. The dielectric constant of the lunar regolith, the velocity of propagation, the reflection, refraction and transmission at interfaces, and the resolution are discussed. The model is further used to numerically simulate and analyze temporal variations in the echo obtained from the LPR attached on CE-3's rover, to reveal the location and structure of lunar regolith. The thickness of the lunar regolith is calculated by a comparison between the simulated radar B-scan images based on the model and the detected result taken from the CE-3 lunar mission. The potential scientific return from LPR echoes taken from the landing region is also discussed.

The Chang'e-3 (CE-3) mission is China's first exploration mission on the surface of the Moon that uses a lander and a rover. Eight instruments that form the scientific payloads have the following objectives: (1) investigate the morphological features and geological structures at the landing site; (2) integrated in-situ analysis of minerals and chemical compositions; (3) integrated exploration of the structure of the lunar interior; (4) exploration of the lunar-terrestrial space environment, lunar surface environment and acquire Moon-based ultraviolet astronomical observations. The Ground Research and Application System (GRAS) is in charge of data acquisition and pre-processing, management of the payload in orbit, and managing the data products and their applications. The Data Pre-processing Subsystem (DPS) is a part of GRAS. The task of DPS is the pre-processing of raw data from the eight instruments that are part of CE-3, including channel processing, unpacking, package sorting, calibration and correction, identification of geographical location, calculation of probe azimuth angle, probe zenith angle, solar azimuth angle, and solar zenith angle and so on, and conducting quality checks. These processes produce Level 0, Level 1 and Level 2 data. The computing platform of this subsystem is comprised of a high-performance computing cluster, including a real-time subsystem used for processing Level 0 data and a post-time subsystem for generating Level 1 and Level 2 data. This paper describes the CE-3 data pre-processing method, the data pre-processing subsystem, data classification, data validity and data products that are used for scientific studies.

The Extreme Ultraviolet Camera (EUVC) onboard the Chang'e-3 (CE-3) lander is used to observe the structure and dynamics of Earth's plasmasphere from the Moon. By detecting the resonance line emission of helium ions (He+) at 30.4 nm, the EUVC images the entire plasmasphere with a time resolution of 10 min and a spatial resolution of about 0.1 Earth radius (R-E) in a single frame. We first present details about the data processing from EUVC and the data acquisition in the commissioning phase, and then report some initial results, which reflect the basic features of the plasmasphere well. The photon count and emission intensity of EUVC are consistent with previous observations and models, which indicate that the EUVC works normally and can provide high quality data for future studies.

To improve our understanding of the formation and evolution of the Moon, one of the payloads onboard the Chang’e-3 (CE-3) rover is Lunar Penetrating Radar (LPR). This investigation is the first attempt to explore the lunar subsurface structure by using ground penetrating radar with high resolution. We have probed the subsurface to a depth of several hundred meters using LPR. In-orbit testing, data processing and the preliminary results are presented. These observations have revealed the configuration of regolith where the thickness of regolith varies from about 4 m to 6 m. In addition, one layer of lunar rock, which is about 330 m deep and might have been accumulated during the depositional hiatus of mare basalts, was detected.

Lunar Penetrating Radar (LPR) onboard the rover that is part of the Chang’e-3 (CE-3) mission was firstly utilized to obtain in situ measurements about geological structure on the lunar surface and the thickness of the lunar regolith, which are key elements for studying the evolutional history of lunar crust. Because penetration depth and resolution of LPR are related to the scientific objectives of this mission, a series of ground-based experiments using LPR was carried out, and results of the experimental data were obtained in a glacial area located in the northwest region of China. The results show that the penetration depth of the first channel antenna used for LPR is over 79 m with a resolution of 2.8 m, and that for the second channel antenna is over 50.8 m with a resolution of 17.1 cm.

Single filament tapes with different Ca contents Bi2.1Sr1.96Ca x Cu2.0O8+δ (x = 0.90, 0.95, 1.00, and 1.05) were prepared by powder in tube (PIT) process. The introduction of Ca nonstoichiometry caused systematic changes in the phase compositions of the final tapes, thus changing the chemical compositions of Bi-2212 phase. The increase of critical temperature T c from 81.2 to 84.2 K can be attributed to the carrier concentration change. The critical current density, J c and flux pinning properties were measured and evaluated at 4.2 K and high field (0–20 T) with the variation of Ca content. Obvious improvements of J c were obtained with the Ca content of x = 0.95 and 1.05 under perpendicular field, which implied that the chemical compositions changes of Ca could effectively lead to the formation of lattice defects, thus enhancing the flux pinning properties on the superconducting layers.

In the process of lunar exploration, and specifically when studying lunar surface structure and thickness, the established lunar regolith model is usually a uniform and ideal structural model, which is not well-suited to describe the real structure of the lunar regolith layer. The present study aims to explain the geological structural information contained in the channel 2 LPR (lunar penetrating radar) data. In this paper, the random medium theory and Apollo drilling core data are used to construct a modeling method based on discrete heterogeneous random media, and the simulation data are processed and collected by the electromagnetic numerical method FDTD (finite-difference time domain). When comparing the LPR data with the simulated data, the heterogeneous random medium model is more consistent with the actual distribution of the media in the lunar regolith layer. It is indicated that the interior structure of the lunar regolith layer at the landing site is not a pure lunar regolith medium but rather a regolith-rock mixture, with rocks of different sizes and shapes. Finally, several reasons are given to explain the formation of the geological structures of the lunar regolith layer at the Chang’E 3 landing site, as well as the possible geological stratification structure.

The epitaxial growth of the buffer layer on a textured metal substrate has a significant influence on the performance of coated conductors, which provides the potential to support a high current for electric utility and high magnetic field applications at 77 K. In this paper, we have fabricated the CeO2 buffer layer on YSZ (yttria-stabilized zirconia) (00l) single crystal substrates by the chemical solution deposition (CSD) method in different annealing atmospheres. The results show that both the thermal decomposition behavior of the precursor solution and the annealing atmosphere have an important effect on the epitaxial growth process of the CeO2 buffer layer. The large oxygen partial pressure in annealing atmosphere is to the disadvantage of the epitaxial growth of CeO2 (00l) crystal face with high energy. Moreover, the epitaxial growth of the CeO2 (00l) crystal plane goes against a decrease in the surface roughness of the CeO2 film. Therefore, it can be considered that the orientation growth of the CeO2 buffer layer and its surface morphology evolution may be related to the thermal decomposition behavior of precursor solution and the change of oxygen vacancies concentration.

The microwave radiometer (MRM) onboard the Chang' E-1 (CE-1) lu- nar orbiter is a 4-frequency microwave radiometer, and it is mainly used to obtain the brightness temperature (TB) of the lunar surface, from which the thickness, tem- perature, dielectric constant and other related propertie s of the lunar regolith can be derived. The working mode of the CE-1 MRM, the ground calibration (including the official calibration coefficients), as well as the acquisiti on and processing of the raw data are introduced. Our data analysis shows that TB increases with increasing fre- quency, decreases towards the lunar poles and is significant ly affected by solar illumi- nation. Our analysis also reveals that the main uncertainty in TB comes from ground calibration.

We have studied the effect of annealing atmosphere on the epitaxial growth process of La 2 Zr 2 O 7 (LZO) thin films on different substrates fabricated by metal-organic deposition (MOD) method. The structure, texture and morphology of LZO films were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). Our results show that the epitaxial growth process of LZO thin film does not completely depend on the lattice mismatch degree between LZO and substrate, and it may be related to the oxygen vacancy defects and the lattice ordering degree. Moreover, the decrease of the lattice oxygen vacancy defects may be beneficial to suppressing the stress and strain relaxation within epitaxial film. The grain boundary concentration in epitaxial films is also related to their strain relaxation process. These results are significant not only to improving the performance of coated conductors, but also to developing other epitaxial oxide thin film on textured substrate.

Microstructure and kinetics of the cubic phase formation are studied in ZrO2–MnO2 diffusion couple. During annealing in Ar, no other compounds are detected except the zirconia solution. With diffusion of Mn ions from manganese oxide to ZrO2, the cubic zirconia are found at the phase interface. The growth kinetics of the cubic zirconia solution layer in the submicrometer scale are analyzed. The growth behavior of the cubic zirconia layer is better described by the grain boundary diffusion model, and our experiment data exhibit a t 1/4 dependence on time. The deviation from the experiment data to the theoretical value is also explained.

The Extreme Ultra-Violet Camera (hereafter EUVC) is a scientific payload onboard the lander of the Chang’E-3 (hereafter CE-3) mission launched on December 1st, 2013. Centering on a spectral band around 30.4 nm, EUVC provides the global images of the Earth’s plasmasphere from the meridian view, with a spatial resolution of \(0.1~R_{\oplus}\) in \(150 \times 150~\mbox{pixels}\) and a cadence of 10 minutes. Along with the data being publicly released online, some unsettled issues in the early stage have been clarified, including the geometrical preparations, the refined approach on the coefficient \(K\) for the background, and the alignment among the images. A demo of data after all the above processes is therefore presented as a guidance for users who are studying the structure and dynamics of the plasmasphere.

YBCO films were fabricated by using a modified precursor solution, which was prepared by mixing yttrium trifluoroacetate, barium trifluoroacetate, and a fluorine-free copper precursor. Crack-free films have been obtained in a rapid pyrolysis process. The texture, microstructure and superconducting properties of films were characterized by x-ray diffraction, scanning electron microscopy, and the inductive method, respectively. The effect of the heating rate on the phase formation, texture and critical properties (Jc) of YBCO films was investigated. The texture and critical current density varied significantly with the heating rate. Moreover, the Jc of 1.7 MA/cm2 was obtained for YBCO films prepared at the heating rate of 3 K/min.

The morphology and the formation of Y2BaCuO5 phase in powder melting processed YBa2Cu3O7−x superconductors were investigated. The experimental results show the heat treatment can not change the shape of Y2BaCuO5 particles in powder melting processed samples. The formation of round Y2BaCuO5 phase is due to relative content of each constitution of precursor powders in powder melting process. For powder melting process, the excessive liquid phase is eliminated, which restrains the preferred growth of Y2BaCuO5 particles.

T 3 SiC 2 bulks have been synthesized by infiltrating Si liquid into porous precursor pellets composed of solid TiC and Ti powders. Silicon pellets were placed at the bottom of the precursor pellets as the liquid source. The starting compositions can be represented by the formula 2TiC + Ti + x Si, where x = 1.0, 1.2, 1.5 and 1.8, respectively. The phase formation and microstructure of the bulks were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS) system. The results demonstrated that the TiC/Ti precursor pellet could only react with Si completely when the x value is 1.8. Impurities SiC, Ti–Si binary compounds and Ti 8 C 5 appeared along the silicon diffusion direction. It is found that the compositions of impurities strongly depended on the Si-concentration. Reaction mechanism of this Ti 3 SiC 2 infiltration synthesis has also been discussed based on the Si-concentration changes on the diffusion path.

Using X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area measurement, ultraviolet-visible diffuse reflection spectra, and photoluminescence spectroscopy, the effect of mechanical milling on the photocatalytic activity of g-C3N4 photocatalyst was investigated. The rhodamine B, as a photodegrading goal, was used to evaluate the photocatalytic activity of g-C3N4. The experimental results indicate that the milling treatment is an effective method to improve the photocatalytic activity of g-C3N4. The enhanced photocatalytic activity was attributed to the improvement in catalyst’s surface area and dye adsorption on catalyst surface. Moreover, checking the luminescence properties of g-C3N4, it is found that the photocatalytic active sites on g-C3N4 are likely the same as luminescence sites.

Brightness temperature is a main index to reflect the energy of microwave radiation of an object. Using lunar brightness temperature data, physical properties of lunar regolith, such as thickness, heat flow and dielectric permittivity, could be interpreted. There are two methods to study brightness temperature distribution of the moon: the first is used to measure lunar brightness temperature by radio observation or spaceborne microwave radiometers, and the second is used to simulate calculation by the physical model. On the basis of the measurements of lunar brightness temperature in the history, this study analyzed the main physical model of lunar brightness temperature, also including its theory and influence factors. The authors concluded that surface and subsurface temperatures of the moon, dielectric properties and layered structure of lunar regolith were the main factors affecting the global brightness temperature of the moon. These factors should be quantified in detail in the future research.

The effects of BaZrO 3 addition on the thermal behavior and microstructure of YBCO superconductors have been investigated. The differential thermal analysis indicates that the peritectic decomposition temperature of YBCO precursor powder is not change when BaZrO 3 is doped. The solidification temperature of YBCO changes with increasing of BaZrO 3 addition, thus the window of solidification temperature is affected. The results of scanning electron microscopy show that the BaZrO 3 particles are accumulated along the growth boundary, which result in the constitutional segregation of YBCO. The pushing–trapping theory is used to explain the phenomenon of segregation in the YBCO matrix.

Novel chiral ligands of dihydro-QUINAP (FLiNAP) and dihydro-QUINOL (FLiNOL) have been synthesized in optically pure forms.

We have investigated the melting behavior of precursor powder for YBa 2 Cu 3 O 7− x superconducting bulks prepared by powder melting process (PMP). The phase transition and the melting process have been studied by high temperature X-ray powder diffractometer and differential analyzer. The results have shown that the PMP precursor powders including Y 2 BaCuO 5 , BaCuO 2 and CuO can transform into the YBa 2 Cu 3 O 7− x phase if the heating rate is not very high, whereas the YBa 2 Cu 3 O 7− x would not appear when the fast heating rate is used. The microstructure of these samples prepared by different heating rates has been also investigated by scanning electron microscopy. The results are available to understanding the mechanism of powder melting process.

A highly regio- and stereo-selective phosphine-catalyzed [3+2] annulation reaction between allylic compounds and 2-substituted 1,1-dicyanoalkenes through a catalytic phosphorus ylide reaction was developed. This reaction has the total reversed regioselectivity compared to that of the reactions of activated alkenes without the 2-substituents or reactions using the allenoates as the C3 component.

This article describes the synthesis of a new chiral amino phosphine ligand based on an amino naphthol starting material, which is resolved efficiently by using l -tartaric acid. The asymmetric induction of the ligand in the Pd(0)-catalyzed allylic substitution of 1,3-diphenylprop-2-en-1-yl acetate with dimethyl malonate was investigated. Good yields and enantiomeric excesses up to 78% of the product were obtained.

Based on the bioactivity and biocompatibility of hydroxyapatite (HA) and the excellent mechanical performance of polyamide 66 (PA66), a composite of nanograde HA with PA66 was designed and fabricated to mimic the structure of biological bone which exhibits a composite of nanograde apatite crystals and natural polymer. The HA/PA66 composite combines the bioactivity of HA and the mechanical property of PA66. This study focused on the preparation method of HA/PA66 composite and the influence of HA crystals on the characterization of the composite. HA slurry was used directly to prepare HA/PA66 composite by a solution method, in which HA is able to form hydrogen bond, i.e. chemical bonding with PA66. The nano-HA needle-like crystals treated by hydrothermal method are better in the particle size distribution and the particle dispersion. The morphology, crystal structure and crystallinity as well as crystal size of these needle-like crystals are similar to bone apatite. The nano-HA needle-like crystals dispersed uniformly in PA66 matrix with reinforcement effect and can prevent the micro-crackle spreading into cleft and fracture during the deformation process. The mechanical testing shows that the nano-HA/PA66 composite has a good mechanical property, and may be a promising bone replacement material.

Lunar Penetrating Radar (LPR) has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise. First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method (CCM) is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m (e r = 6.6) and from 13.0 m to 17.5 m (e r = 2.3), respectively.

Bi2Sr2CaCu2O8+δ (Bi-2212) silver sheathed round wire is a promising and practical material for high field superconducting insert magnet in the range of 25–30 T. The effect of oxygen content of Bi-2212 on the critical current density (Jc) of multi-filamentary Bi-2212/Ag wires has been investigated. During the Bi-2212 wire fabrication, partial melting and solidification process was employed. Short samples which were cut from the same wire were annealed at 500 °C in various atmospheres for post-annealing. The morphology, lattice parameters and oxygen contents were characterized by SEM, XRD and a thermal gravimetric analyzer (TGA). The critical current (Ic) and the superconducting transition temperature (Tc) were measured by a four-probe method. Lower O2 pressure can break the Bi-O chains, reduce the oxygen contents and change the lattice structure of Bi-2212 from tetragonal into orthorhombic. The Tc values of samples increase from 81.6 K to 91 K and the highest Jc of samples after post-annealing is almost three times higher than that of the initial sample.

Two kinds of tri-calcium phosphate ceramics (Ca/P = 1.50), alpha-TCP and beta-TCP, which has the same macrostructure and microstructure, but different phase composition, were implanted in dorsal muscles of dogs. The samples were retrieved at 30, 45 and 150 days, respectively, after implantation, and were analyzed histologically. There were critically different tissue responses between alpha-TCP ceramic and beta-TCP ceramic. Higher cell populations were observed inside the pores of beta-TCP than those of alpha-TCP, bone tissue was found in beta-TCP at 45 and 150 days, but no bone formation could be detected in any alpha-TCP implants in this study. On the other hand, the bone tissue in beta-TCP seemed to degenerate at 150 days. The results indicate that porous beta-TCP can induce bone formation in soft tissues of dogs; while the rapid dissolution of the ceramic and the higher local Ca2+, PO(4)3- concentration due to the rapid dissolution of alpha-TCP may resist bone formation in alpha-TCP and the less rapid dissolution of beta-TCP may be detrimental to already formed bone in beta-TCP.

International audience; Kilometer level 6 + 1 filamentary MgB2 wires sheathed with Nb/Cu composite tube was fabricated by in situ powder-in-tube (PIT) method, nonferromagnetic Nb was employed as the centre reinforced materials. There is no any annealing in the whole fabrication process due to the excellent ductility of Nb/Cu based tube. The (Mg, B)/Nb/Cu composite wire was fabricated to the target size of 1.4 mm in diameter and heat treated at 680 °C for 2 h in a vacuum furnace. Microstructure, superconductivity, mechanical properties and homogeneity of critical current were measured respectively. The transport engineering critical current density (Jce) reaches 2.5 × 104 A/cm2 at 20 K, 1 T. The results show a good potential to fabricate high performance MgB2 wires at ambient pressure for practical application.

A novel phosphine-catalyzed reaction of modified allylic compounds, including acetates, bromides, chlorides, or tert-butyl carbonates derived from the Morita-Baylis-Hillman (MBH) reaction with tropone to yield [3+6] annulation products in excellent yields was developed. It offers a simple and convenient method for constructing bridged nine-membered carbocycles.

International audience; This paper aims at examining the bending mechanical properties of MgB2/Nb/Cu wires and tapes fabricated with in situ powder in tube (PIT) method. The bending characteristics of five different MgB2 wires and tapes including four wires with mono-, 6-, 12-, and 36-filamentary and a 6-filamentary tapes were tested. The critical current density (Ic) as a function of bending diameter was measured and compared for all the prepared samples. This study aims at giving a clear picture of the optimum bending conditions at which MgB2 wires will possess a high current carrying capacity for practical applications.

The compounds Hf 1− x Mn x O 2− δ ( x = 0–0.5) have been synthesized by conventional solid state reaction method in Ar. Rietveld analysis of X-ray diffraction data has shown that the Mn-doped HfO 2 undergoes a structural transformation from monoclinic to cubic phases, which is significantly dependent on the Mn content under current synthesis conditions. The stabilized cubic structure by multivalent Mn ion doping can transform to the monoclinic structure when annealed at high temperature in air. Transmission electron microscopy and electron diffraction investigations have also confirmed the existence of the high-temperature cubic structure. A mechanism of stabilizing the high-temperature cubic phase in the Hf 1− x Mn x O 2− δ system has been analyzed based on considerations of manganese substitution effect for hafnium ions and oxygen vacancy formation.

Creep is of importance for evaluating the materials deterioration and deformation of the cathodes in aluminum reduction cells. The purpose of this work is to obtain the creep data for various industrial cathode products. A modified Rapoport equipment was used for measuring the creep behaviors during aluminum electrolysis with CR=4.0 and at temperature of 965°C. Testing samples were taken from three typical industrial cathode blocks: semi-graphitic, full graphitic and graphitized carbon products and were characterized for their graphitized degree using XRD method. The values of d002 for all cathode samples were lowered after aluminum electrolysis, and the graphitized cathode showed a smaller creep deformation than those of semi-graphitic and full graphitic cathode samples. The results have demonstrated a correlation between the graphitization degree and the creep deformation using a consistent testing procedure, and the obtained data will be useful for better quality control in cathode manufacture and improvement in cell structure design.

A self-catalytic aza-Friedel–Crafts method was employed to generate 1-naphtholyl tetrahydroisoquinoline products under neat conditions. In addition, a derivative was prepared in its enantiomerically pure form and has shown moderate activity for asymmetric catalysis in the asymmetric diethylzinc addition to aldehydes.

Based on the bioactivity and biocompatibility of hydroxyapatite (HA) and the excellent mechanical performance of polyamide 66 (PA66), a composite of nanograde HA with PA66 was designed and fabricated to mimic the structure of biological bone which exhibits a composite of nanograde apatite crystals and natural polymer. The HA/PA66 composite combines the bioactivity of HA and the mechanical property of PA66. This study focused on the preparation method of HA/PA66 composite and the influence of HA crystals on the characterization of the composite. HA slurry was used directly to prepare HA/PA66 composite by a solution method, in which HA is able to form hydrogen bond, i.e. chemical bonding with PA66. The nano-HA needle-like crystals treated by hydrothermal method are better in the particle size distribution and the particle dispersion. The morphology, crystal structure and crystallinity as well as crystal size of these needle-like crystals are similar to bone apatite. The nano-HA needle-like crystals dispersed uniformly in PA66 matrix with reinforcement effect and can prevent the micro-crackle spreading into cleft and fracture during the deformation process. The mechanical testing shows that the nano-HA/PA66 composite has a good mechanical property, and may be a promising bone replacement material.

A novel image texture pattern classification (ITPC) method based on statistical modeling of image spatial structures (ISSs) is presented due to the perceptual perspective that the visual appearance of image texture pattern (ITP) visually depends on the random organization of local homogeneous fragments. Firstly, the oriented Gaussian derivative filters (OGDFs)-based ISS characteristics expression method is introduced. Then, the Weibull distribution (WD) behavior of ISSs, boiled down to the randomly-distributed local homogeneous fragments, is explicated by the sequential fragmentation theory (SFT). Finally, the WD-based ISS feature parameters, directly related to the human vision perception(HVP) system, are extracted and used to ITPC by a partial least squares-discriminant analysis (PLS-DA)-based classifier. The effectiveness of the proposed ISS-based ITPC method is verified by extensive experiments on three different texture image databases and compared with some classic statistics-based ITP identification methods.