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In view of the difficulties such as coarse microstructure, performance degradation and excessive residual stress during the preparation of Ti-6Al-4V layers by laser cladding, the microstructure and mechanical properties of such a Ti-6Al-4V coating were optimized and improved based on the plastic deformation effect caused by laser shock peening (LSP). The characteristics of phase composition, changes in microstructure and morphology, grain plastic deformation and the influence of mechanical properties of the laser clad Ti-6Al-4V coating were studied pre- and post-LSP. The results indicate that the α/α' phase content increases and the β phase content decreases after LSP. The β phase and acicular martensite α' phase is refined significantly and divided, and the basket structure presents a more dense and staggered distribution after LSP. Laser cladding causes the grains in the Ti-6Al-4V coating to undergo plastic strain and the degree of grain refinement was significantly improved following LSP. The microhardness at the top of the laser clad Ti-6Al-4V coating increases from 23 to 30% compared after LSP. At the same time, the LSP promotes the transformation of residual tensile stress to compressive stress on the surface of the laser clad Ti-6Al-4V coating, with an average residual compressive stress value of about 339 MPa. This study provides theoretical and methodological references for optimizing the microstructure and properties of Ti-6Al-4V coatings. [ABSTRACT FROM AUTHOR]

Context. Gaps in circumstellar disks can signal the existence of planetary perturbers, making such systems preferred targets for direct imaging observations of exoplanets. Aims. Being one of the brightest and closest stars to the Sun, the photometric standard star Vega hosts a two-belt debris disk structure. Together with the fact that its planetary system is being viewed nearly face-on, Vega has been one of the prime targets for planet imaging efforts. Methods. Using the vector vortex coronagraph on Keck/NIRC2 in the Ms band at 4.67 μm, we report the planet detection limits from 1 au to 22 au for Vega with an on-target time of 1.8 h. Results. We reach a 3 MJupiter limit outward of 12 au, which is nearly an order of magnitude deeper than for other existing studies. Combining our observations with existing radial velocity studies, we can confidently rule out the existence of companions more than ~8 MJupiter from 22 au down to 0.1 au for Vega. Interior and exterior to ~4 au, this combined approach reaches planet detection limits down to ~2–3 MJupiter using radial velocity and direct imaging, respectively. Conclusions. By reaching multi-Jupiter mass detection limits, our results are expected to be complemented by the planet imaging of Vega in the upcoming observations using the James Webb Space Telescope to obtain a more holistic understanding of the planetary system configuration around Vega. [ABSTRACT FROM AUTHOR]

In the early stages of planetary system formation, young exoplanets gravitationally interact with their surrounding environments and leave observable signatures on protoplanetary disks. Among these structures, a pair of nearly symmetric spiral arms can be driven by a giant protoplanet. For the double-spiraled SAO 206462 protoplanetary disk, we obtained three epochs of observations spanning 7 yr using the Very Large Telescope's SPHERE instrument in near-infrared J-band polarized light. By jointly measuring the motion of the two spirals at three epochs, we obtained a rotation rate of − 0. ° 85 ± 0. ° 05 yr − 1 . This rate corresponds to a protoplanet at 66 ± 3 au on a circular orbit dynamically driving both spirals. The derived location agrees with the gap in ALMA dust-continuum observations, indicating that the spiral driver may also carve the observed gap. What is more, a dust filament at ∼63 au observed by ALMA coincides with the predicted orbit of the spiral-arm-driving protoplanet. This double-spiraled system is an ideal target for protoplanet imaging. [ABSTRACT FROM AUTHOR]

Exchange coupling constant (J) is an important magnetic parameter for the design of the antiferromagnetically coupled medium. So far, the relationship between the exchange bias (H[SUBex]) and exchange coupling constant, H[SUBex] = J/M[SUBs]t, which is deduced from the ferromagnetic-antiferromagnetic coupled system under some conditions, was commonly used to estimate the exchange coupling constant J for such medium. This article first deduces an accurate equation of the exchange coupling constant (J) and the exchange bias H[SUBex] for the antiferromagnetically coupled medium in different applied field directions. After considering the effect of easy axis distribution of the magnetic grains in the recording medium, the equation for the antiferromagnetically coupled medium is further revised as H[SUBex] = aJ/M[SUBs]t. a is a constant and depends on the easy axes distribution of magnetic grains, the exchange coupling constant, and the ratio of magnetic parameters between the two magnetic layers. a is found to range from 0.2 to 0.5 for isotropic media to oriented medium. The J value may have been heavily underestimated before by using the previous equation. [ABSTRACT FROM AUTHOR]

In this article, the magnetization reversal process and thermal stability of perpendicular coupled film glass/Ti 40 nm/CoCrPtB 35 nm/CoDy 20 nm/Ti 4 nm were presented. The exchange coupling constant with Dy content near the compensated point is as high as 1.3 erg/cm2. The dependence of exchange coupling strength on the Dy content and the thickness of CoDy layer was investigated. The thermal stability of the coupled films showed an increase over 100%. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

In this article, the large anisotropy and strong coupling between rare-earth (RE= Sm, Dy, Tb etc.) metal and transition metal (TM= Co, Fe, etc.) are proposed to be utilized to improve the thermal stability (K[sub u]V[sup ...]/k[sub B]T) and coercivity (H[sub c]) of high-density recording media. The effects of Dy doping, which was added to the Cr underlayer and Cr overcoat layer, on magnetic and reversal properties are presented. It was found that Dy doping in the Cr[sub 1-x]Dy[sub x] underlayer and overcoat layer resulted in an increase of the K[sub u]V[sup ...]/k[sub B]T and coercivity (H[sub c]). The appreciable increases in K[sub u]V[sup ...]/k[sub B]T and H[sub c] indicate that Dy doping into the underlayer and intermediate layer is promising for the preparation of high-density recording media. [ABSTRACT FROM AUTHOR]

A new vector hysteresis model is presented, based on the function approximation capabilities of feed-forward neural networks. Two-dimensional circular and elliptical magnetization of laminated SiFe steel sheets can be successfully handled by the model. A feed-forward neural network with four inputs, derived at each time step from the time-dependent magnetic induction vector, yields an accurate prediction of the magnetic field strength vector. Measurement results for a steel sheet sample are used to train and test the neural network. The model accuracy is good and can be easily adapted to the requirements of the application by extending or reducing the network training set and thus the required amount of measurement data. Besides, the presented technique is fast, requires no large data set, and applies standard neural network algorithms. Future extension of the model to other magnetization patterns is possible. [ABSTRACT FROM AUTHOR]

BSTRACT [ABSTRACT FROM AUTHOR]

Peng L, Ren LB, Dong G, Wang CL, Xu P, Ye L, Zhou XD. Wnt5a promotes differentiation of human dental papilla cells. International Endodontic Journal, 43, 404–412, 2010. Aim To investigate the role of Wnt5a in the process of differentiation of human dental papilla cells (HDPCs). Methodology Recombinant adenovirus encoding full-length Wnt5a cDNA was constructed to investigate the biological role of Wnt5a on the differentiation of HDPCs. The effect of Wnt5a on HDPCs differentiation was determined by ALP activity assay, ALP staining and mineral induction assay. Mineralization-related gene expressions were assessed by RT-PCR. Results Immunostaining revealed Wnt5a expression in the odontoblast layer and dental papilla tissue. Over-expression of Wnt5a by transfecting HDPCs with an Wnt5a-carrying construct increased ALPase activity and the formation of mineralized nodules of HDPCs. RT-PCR analysis showed that the expressions of mineralization-related genes, such as bone sialoprotein, collagen type I, osteonectin, osteopontin (OCN), dentine matrix protein-1 were up-regulated by Wnt5a. Conclusions Wnt5a promoted differentiation of HDPCs. [ABSTRACT FROM AUTHOR]

We analyzed multi-wavelength observations of the eruption of a small-scale filament on the quiet Sun. The filament first became thicker, then broke into two, and eventually underwent a partial eruption with possible rotating motion. The eruption was followed by a small flare with three bright kernels on either side of the eruptive section in H α and a small coronal dimming near one end of this section in EUV and soft X-ray. On the photosphere, MDI magnetograms show the flux emergence or motions and cancellation between opposite polarities before and during the filament eruption. We find that this small-scale filament shows the similar characteristics as the previous findings in the large-scale filament eruptions on the multi-wavelength, indicating the common nature. [ABSTRACT FROM AUTHOR]

In the present study, ceramic injection moulding was used to fabricate SiC preform for pressureless infiltration. The influence of various binder compositions consisting of paraffin wax (PW), high density polyethylene (HDPE), polypropylene (PP) and stearic acid (SA) on the characteristics of injection moulded SiC feedstocks has been investigated over the 150–180°C temperature range and the 4–1259 s-1 shear range. The results show that all the feed stocks exhibit pseudoplastic flow behaviour. Compared with 65PW–15HDPE–5SA or 65PW–15PP–5SA, the wax based binder of multi polymer components (65PW–15HDPE–15PP–5SA) is a more suitable binder for SiC ceramic injection moulding due to its good comprehensive rheology and pyrolytic properties. Over a range of temperatures and shear rates, the feedstock made of 65PW–15PP–5SA binder has the lowest viscosity than the other two, which can be attributed to the low molecule weight of PP. [ABSTRACT FROM AUTHOR]

Some atomic decomposition theorems are proved in vector-valued weak martingale Hardy spaces w p Σα( X), w p Q α( X) and wD α( X). As applications of atomic decompositions, a sufficient condition for sublinear operators defined on some vector-valued weak martingale Hardy spaces to be bounded is given. In particular, some weak versions of martingale inequalities for the operators f*, S ( p)( f) and σ( p)( f) are obtained. [ABSTRACT FROM AUTHOR]

The internal and external stresses around a triple junction of copper have been analysed by a disclination model and by a three-dimensional anisotropic finiteelement method respectively. The results indicate that the internal stress depends on whether the triple line is an I-line or a U-line. At the triple line the elastic strain energy concentrations caused by external stresses depend on both the orientations of the component grains and the loading directions. For a loading direction parallel to the triple line, the elastic energy concentration is usually large. For a loading direction perpendicular to the triple line, the elastic energy concentration is complex; in some cases, elastic energy dispersion can occur but, in other cases, the elastic energy concentration is much larger than that with the loading direction parallel to the triple line. [ABSTRACT FROM AUTHOR]

Background: The Chinese Shaziling pig is representative of good meat quality but has been scarcely utilized on commercial farms because of the unpleasing growth and carcass traits. Methods: The growth performance, carcass characteristics, meat quality and fatty acids profile were analyzed among (Berkshire × Shaziling) × (Berkshire × Shaziling) (BS×BS), BS×S, Shaziling (S×S) and S×BS pigs. Result: BS×BS pigs exhibited higher growth rate and superior carcass performance. Each breed possessed desirable meat quality, as evidenced by moderate pH, color score, IMF content and shear force value, among which the performance of S×BS pigs was prominent. Take account of the contents of SFAs, MUFAs, PUFAs and PUFAs/SFAs value, the eating quality of S×BS pigs was favorable and the meat of BS×BS pigs, by contrast, was helpful for human health with advanced nutritional value. In summary, BS × BS pigs is more effective for commercial development of Shaziling pigs and providing healthy pork products. [ABSTRACT FROM AUTHOR]

We report on magnetic and magnetotransport properties of single-crystalline Co2 MnSi films grown by using conventional pulsed laser deposition (PLD) method on moderately heated semiconductor GaAs(001) substrates. The films exhibit the expected high Curie temperature and a strong in-plane uniaxial magnetic anisotropy with the easy axis of magnetization along the [1-10] direction. A saturation magnetization of 950 emu/cm³ was measured at 5 K. The temperature dependence of the resistivity shows metallic behavior down to low temperatures. At 5 K, a rather large negative magnetoresistance (MR) of 1.26% has also been observed. [ABSTRACT FROM AUTHOR]

Although the study of X-ray binaries has led to major breakthroughs in high-energy astrophysics, their circumbinary environment at scales of ∼100–10,000 au has not been thoroughly investigated. In this paper, we undertake a novel and exploratory study by employing direct and high-contrast imaging techniques on a sample of X-ray binaries, using adaptive optics and the vortex coronagraph on Keck/NIRC2. High-contrast imaging opens up the possibility to search for exoplanets, brown dwarfs, circumbinary companion stars, and protoplanetary disks in these extreme systems. Here we present the first near-infrared high-contrast images of 13 high-mass X-ray binaries located within ∼2–3 kpc. The key results of this campaign involve the discovery of several candidate circumbinary companions ranging from substellar (brown dwarf) to stellar masses. By conducting an analysis based on Galactic population models, we discriminate sources that are likely background/foreground stars and isolate those that have a high probability (≳60%–99%) of being gravitationally bound to the X-ray binary. This paper seeks to establish a preliminary catalog for future analyses of proper motion and subsequent observations. With our preliminary results, we calculate the first estimate of the companion frequency and the multiplicity frequency for X-ray binaries: ≈0.6 and 1.8 ± 0.9, respectively, considering only the sources that are most likely bound to the X-ray binary. In addition to extending our comprehension of how brown dwarfs and stars can form and survive in such extreme systems, our study opens a new window to our understanding of the formation of X-ray binaries. [ABSTRACT FROM AUTHOR]

Investigated is the resource allocation problem in OFDMA networks by introducing the sleep mode. In contrast to the existing literature, which mainly focuses on improving network throughput by increasing energy consumption energy efficient resource allocation with sleep mode is considered under which some components of the transmitter can be shut down to save energy. A mix integer programming problem is proposed to minimise energy consumption while satisfying the average data rate requirement. The existence of a unique globally optimal resource allocation solution is demonstrated and an iterative algorithm is developed to obtain it. The simulation result shows that the proposed algorithm can effectively save total energy consumption especially when the network is under low load condition. [ABSTRACT FROM AUTHOR]

Observations and theories reveal that star-forming regions eject their members during the early evolution of the cluster. We present an initial search for stars ejected from the young cluster IC 348 based on an analysis of Gaia EDR3 astrometry of previously identified members. We identify six candidate walkaway stars with projected velocities of 5–8 km s−1. The candidate with properties most consistent with a walkaway star, V701 Per, was likely ejected from a small group to the west of IC 348. Three candidates are currently located or have proper motions that trace back to the center of IC 348, though their classification as walkaway stars may also be affected by large astrometric errors. Two other candidate walkaway stars were likely born in other subgroups around IC 348 within the Perseus star-forming region. Since our search criteria are restricted to previously identified members of IC 348, we did not identify any stars that were ejected at high velocities and traveled far from the cluster. Our study suggests that ejections have potentially occurred in both the central region of IC 348 and other subgroups in Perseus. Extending the search range will lead to more candidate ejections and constrain the dynamic properties and evolution of IC 348 by comparing with simulations. [ABSTRACT FROM AUTHOR]

BACKGROUND: Global longitudinal strain (GLS) is an accurate and reproducible parameter of left ventricular (LV) systolic function which has shown meaningful prognostic value. Fast, user-friendly, and accurate tools are required for its widespread implementation. We aim to compare a novel web-based tool with two established algorithms for strain analysis and test its reproducibility. METHODS: Thirty echocardiographic datasets with focused LV acquisitions were analyzed using three different semi-automated endocardial GLS algorithms by two readers. Analyses were repeated by one reader for the purpose of intra-observer variability. CAAS Qardia (Pie Medical Imaging) was compared with 2DCPA and AutoLV (TomTec). RESULTS: Mean GLS values were -15.0 ± 3.5% from Qardia, -15.3 ± 4.0% from 2DCPA, and -15.2 ± 3.8% from AutoLV. Mean GLS between Qardia and 2DCPA were not statistically different (p = 0.359), with a bias of -0.3%, limits of agreement (LOA) of 3.7%, and an intraclass correlation coefficient (ICC) of 0.88. Mean GLS between Qardia and AutoLV were not statistically different (p = 0.637), with a bias of -0.2%, LOA of 3.4%, and an ICC of 0.89. The coefficient of variation (CV) for intra-observer variability was 4.4% for Qardia, 8.4% 2DCPA, and 7.7% AutoLV. The CV for inter-observer variability was 4.5%, 8.1%, and 8.0%, respectively. CONCLUSIONS: In echocardiographic datasets of good image quality analyzed at an independent core laboratory using a standardized annotation method, a novel web-based tool for GLS analysis showed consistent results when compared with two algorithms of an established platform. Moreover, inter- and intra-observer reproducibility results were excellent. [ABSTRACT FROM AUTHOR]

Superelasticity is very common in shape memory alloys but is rather difficult to realize in ferroelectric ceramics and had never appeared in normal ferroelectric single crystals. Here we show that guided by a proposed incremental 90° domain switching criterion, large and electric-field-tunable superelastic strains up to 0.85% has been realized in a specially poled BaTiO3 crystal cube via compression loading/unloading with a positive dc bias electric field along the poling direction. Moreover, the tunable superelasticity has a large damping factor of up to 0.76, which is very promising in intelligent damping devices. [ABSTRACT FROM AUTHOR]

Abstract: A new facility had been set up to test the low temperature properties of the short sample of the small-size cable-in-conduit conductor (CICC). The facility consisted of the background magnet which could provide 7T centric magnetic field, a 50kA superconducting transformer which provided sample current, a 500W/4.5K helium refrigerator which produced both the liquid helium (LHe) and supercritical helium (SHe). An ITER CC conductor short sample was prepared and measured in this testing system. T cs of 7.02K (@4.1T, 10kA) and I c of 8.9kA (@4.1T, 7.06K) were measured. [Copyright &y& Elsevier]

To meet the specifications of International Thermonuclear Experimental Reactor correction coil (CC) conductor, a 50 kA superconducting transformer has been designed and manufactured to provide the short sample of the CC conductor the current. The transformer consists of two concentric layer-wound superconducting solenoids with the primary inside the secondary coil. In order to test the transformer, the two legs of the secondary coil were directly connected by superconducting cables. A 500 W/4.5 K refrigerator was used to provide the supercritical helium. The maximum current of 56.3 kA in the secondary coil loop was obtained. [ABSTRACT FROM AUTHOR]

Aims. A comprehensive and homogeneous determination of stellar parameters for the stars observed by the Kepler space telescope is necessary for statistical studies of their properties. As a result of the large number of stars monitored by Kepler, the largest and more complete databases of stellar parameters published to date are multiband photometric surveys. The LAMOST-Kepler survey, whose spectra are analyzed in the present paper, was the first large spectroscopic project, which started in 2011 and aimed at filling that gap. In this work we present the results of our analysis, which is focused on selecting spectra with emission lines and chromospherically active stars by means of the spectral subtraction of inactive templates. The spectroscopic determination of the atmospheric parameters for a large number of stars is a by-product of our analysis. Methods. We have used a purposely developed version of the code ROTFIT for the determination of the stellar parameters by exploiting a wide and homogeneous collection of real star spectra, namely the Indo US library. We provide a catalog with the atmospheric parameters (Teff, log g, and [Fe/H]), radial velocity (RV), and an estimate of the projected rotation velocity (vsini). For cool stars (Teff≤ 6000 K), we also calculated the Hα and Ca ii-IRT fluxes, which are important proxies of chromospheric activity. Results. We have derived the RV and atmospheric parameters for 61 753 spectra of 51 385 stars. The average uncertainties, which we estimate from the stars observed more than once, are about 12 km s-1, 1.3%, 0.05 dex, and 0.06 dex for RV, Teff, log g, and [Fe/H], respectively, although they are larger for the spectra with a very low signal-to-noise ratio. Literature data for a few hundred stars (mainly from high-resolution spectroscopy) were used to peform quality control of our results. The final accuracy of the RV is about 14 km s-1. The accuracy of the Teff, log g, and [Fe/H] measurements is about 3.5%, 0.3 dex, and 0.2 dex, respectively. However, while the Teff values are in very good agreement with the literature, we noted some issues with the determination of [Fe/H] of metal poor stars and the tendency, for log g, to cluster around the values typical for main-sequence and red giant stars. We propose correction relations based on these comparisons and we show that this does not have a significant effect on the determination of the chromospheric fluxes. The RV distribution is asymmetric and shows an excess of stars with negative RVs that are larger at low metallicities. Despite the rather low LAMOST resolution, we were able to identify interesting and peculiar objects, such as stars with variable RV, ultrafast rotators, and emission-line objects. Based on the Hα and Ca II-IRT fluxes, we found 442 chromospherically active stars, one of which is a likely accreting object. The availability of precise rotation periods from the Kepler photometry allowed us to study the dependency of these chromospheric fluxes on the rotation rate for a very large sample of field stars. [ABSTRACT FROM AUTHOR]

A Xianfeng lignite was aminolyzed with a series of amines at 200°C within 1 h. Ethanolamine was found to be a superior solvent for lignite aminolysis under mild conditions. Up to ca. 77 wt% of a Xianfeng lignite could be dissociated with ethanolamine. Solvent-extraction components of aminolysis products of Xianfeng lignite with ethanolamine are mainly water insoluble fractions, water soluble fractions-acetone insoluble, and water soluble fractions-acetone soluble. Water insoluble, water soluble fractions-acetone soluble, and water soluble fractions-acetone insoluble mainly contain about 1 to 2 rings, 2 to 3 rings, and 1 to 4 rings aromatic structure, respectively. [ABSTRACT FROM AUTHOR]

Despite the clinical success of tamoxifen, its resistance remains a major challenge in breast cancer. Here we show that Aurora-A determines tamoxifen sensitivity by regulation of oestrogen receptor (ER)α. Ectopic expression of Aurora-A decreases and depletion of Aurora-A enhances tamoxifen sensitivity in ERα-positive breast cancer. Elevated Aurora-A was significantly associated with the recurrence of ERα-positive tumours. Notably, Aurora-A inhibitor MLN8237, which is currently in clinical trial, synergizes with tamoxifen and overcomes tamoxifen resistance. Furthermore, Aurora-A interacts with and phosphorylates ERα on serine-167 and -305, leading to increase in ERα DNA-binding and transcriptional activity. Elevated levels of Aurora-A are significantly associated with disease-free survival in ERα-positive but not ERα-negative breast cancers. These data suggest that Aurora-A has a pivotal role in tamoxifen resistance and ERα is a bona fide substrate of Aurora-A. Thus, Aurora-A represents a prognostic marker in ERα-positive tumour and a critical therapeutic target in tamoxifen-resistant breast cancer, and Aurora-A inhibitor could be used as either an independent or concurrent agent in tamoxifen-resistant tumour. [ABSTRACT FROM AUTHOR]

The effect of polarization fatigue on the Rayleigh coefficients of ferroelectric lead zirconate titanate (PZT) thin film was systematically investigated. It was found that electrical fatigue strongly affects the Rayleigh behaviour of the PZT film. Both the reversible and irreversible Rayleigh coefficients decrease with increasing the number of switching cycles. This phenomenon is attributed to the growth of an interfacial degraded layer between the electrode and the film during electrical cycling. The methodology used in this work could serve as an alternative way for evaluating the fatigue endurance and degradation in dielectric properties of ferroelectric thin-film devices during applications [ABSTRACT FROM AUTHOR]

Ni-W catalysts supported on activated carbon and Al2O3 were prepared by an incipient wetness impregnation method and characterized by x-ray diffraction and temperature programmed reduction. Heavy oil (distillation temperature: 320–340°C) derived from the direct coal liquefaction process using Shengli coal were hydrotreated using sulfided Ni-W catalysts at 400°C and 5.0 MPa initial H2 pressure. The results showed that the support had a significant influence on the reducibility of metal oxides, hydrodenitrogenation, and hydrodearomatization activities of coal-derived heavy oil. Ni-W/activated carbon exhibited higher decolor performance and hydrodearomatization activities for upgrading the coal-derived heavy oil than the Ni-W/Al2O3 catalyst. [ABSTRACT FROM PUBLISHER]

The article discusses the study which examined the effects of heat transfer and permeability constant in twin-roll strip casting. In the study, a 3D coupling temperature-flow mathematical model was developed to examine the flow and heat transfer in the mushy zone and the entire pool during the casting process. The study also used a Darcy's Law-type of porous media treatment to account for the effect of mushy zone on flow and solidification.

The coefficient of thermal expansion and thermal strain response behaviour of SiCp/Cu composites prepared by spark plasma sintering (SPS) and pressureless infiltration were studied. The CTEs decreased with increasing reinforcement content. For a fixed SiC content, pressurelessly infiltrated specimens exhibited lower CTE than the SPS specimens. The CTEs of SPS specimens agreed well with the ROM model while the CTE of pressurelessly infiltrated specimens was close to Kerner's predictions. The strain hysteresis loops were developed during thermal cycling. The residual stress increased with increasing reinforcement content. The SPS specimens experienced large dimensional change due to the weak interfacial bond while the pressurelessly infiltrated specimens showed negligible strain hysteresis. The interfacial condition has a pronounced effect on the strain hysteresis behaviour. The improved interfacial bond was beneficial to the decreasing of the CTE and improving the dimensional stability of the composite. [ABSTRACT FROM AUTHOR]

Porous titanium implants with large size and complex shape were successfully fabricated by a novel near net forming process, gelcasting, and the effects of processing parameters on the viscosity of the Ti slurry based on acrylamide system, dry green strength, porosity and mechanical properties of sintered body were investigated. The viscosity of Ti slurry with 34 vol.-%Ti and 20 wt-% monomer based on the premix dispersed by 04 wt-%NH4OH is <1 Pa s when the shear rate is >20 s-1. A green body with the strength of 30 MPa can be obtained from the 34 vol.-%Ti slurry with the ratio of monomer to cross-linker from 3 to 120, and when sintered at 1373 K for 15 h, the total porosity and open porosity of porous titanium were 465 and 405% respectively, and its mechanical properties are compressive strength ∼192 MPa, Young's modulus ∼85 GPa, similar to those of human cortical bone and appropriate for implanting purpose. [ABSTRACT FROM AUTHOR]

Biodegradable polymer/bioceramic composites scaffold can overcome the limitation of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. To better mimic the mineral component and the microstructure of natural bone, novel nano-hydroxyapatite (NHA)/polymer composite scaffolds with high porosity and well-controlled pore architectures as well as high exposure of the bioactive ceramics to the scaffold surface is developed for efficient bone tissue engineering. In this article, regular and highly interconnected porous poly(lactide-co-glycolide) (PLGA)/NHA scaffolds are fabricated by thermally induced phase separation technique. The effects of solvent composition, polymer concentration, coarsening temperature, and coarsening time as well as NHA content on the micro-morphology, mechanical properties of the PLGA/NHA scaffolds are investigated. The results show that pore size of the PLGA/NHA scaffolds decrease with the increase of PLGA concentration and NHA content. The introduction of NHA greatly increase the mechanical properties and water absorption ability which greatly increase with the increase of NHA content. Mesenchymal stem cells are seeded and cultured in three-dimensional (3D) PLGA/NHA scaffolds to fabricate in vitro tissue engineering bone, which is investigated by adhesion rate, cell morphology, cell numbers, and alkaline phosphatase assay. The results display that the PLGA/NHA scaffolds exhibit significantly higher cell growth, alkaline phosphatase activity than PLGA scaffolds, especially the PLGA/NHA scaffolds with 10wt.% NHA. The results suggest that the newly developed PLGA/NHA composite scaffolds may serve as an excellent 3D substrate for cell attachment and migration in bone tissue engineering. [ABSTRACT FROM AUTHOR]

SiCp/Cu composites with high reinforcement content (56–65 vol.-%) were fabricated by spontaneously infiltrating copper alloy into porous SiC preform obtained by powder injection moulding. The main influencing factors of the preparation of the preform and the infiltration behaviour of various preforms were studied. The results indicate that the viscosity increases with an increase in powder loading or decreases with an increase in particle size. The feedstocks with bimodal mixture exhibit low viscosity due to the improvement in packing efficiency. When small particles or bimodal mixture with large size ratio were used, the preforms were difficult to be fully infiltrated. The preforms debound in air exhibit lower infiltration rate than the ones debound in vacuum due to the reduction of porosity and the poor wettability between the oxidised layer and copper alloy. Kinetic analysis on the infiltration curves yielded activation energies of 253 kJ mol–1. [ABSTRACT FROM AUTHOR]

Multiferroicity in CoCr2O4 is generally regarded to emerge from the onset of noncollinear spiral magnetic order (Ts ≈ 28 K) due to the inverse Dzyaloshinskii–Moriya interaction, far below the temperature of collinear ferrimagnetic transition (Tc ≈ 96 K). So far, the possibility of multiferroicity appearing in collinear magnetic order has been rarely explored. Here, we report a magnetodielectric effect emerging from the onset of collinear ferrimagnetic transition Tc in CoCr2O4. Based on the postulation of non-centric crystal symmetry and Landau theory, we deduce that such a magnetodielectric effect is attributed to the coexistence of electric and magnetic ordering by the magnetoelectric coupling below Tc. Our results suggest that CoCr2O4 is a natural multiferroic in both noncollinear spiral and collinear magnetic ordering. [ABSTRACT FROM AUTHOR]