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Although Ti2AX has excellent mechanical properties of both metals and ceramics, there are few papers exploring the correlation between mechanics and thermodynamics simultaneously. In this paper, the structure properties, elastic anisotropies, thermodynamic and tensile properties of Ti2AX (A = Al and Ga, X = C and N) MAX phases are studied by first-principles calculations. The results show that these MAX phases have thermodynamical, dynamical, and mechanical stabilities. The calculated anisotropy indexes indicate that the MAX phases are anisotropic in elastic modulus. Ti-X chemical bonds possess covalent-ionic mixed nature. Moreover, the sound velocities and thermal conductivities of these Ti2AX MAX phases are also anisotropic. According to the tensile calculation, the tensile strength along the [110] direction is greater than that along the [001] direction, and fracture failure will occur in the [110] direction. [ABSTRACT FROM AUTHOR]

The concentrations of Cu, Fe, Mn, Ni, Zn, Cr, Pb, and Cd in 37 samples collected from surface sediments from the Inner Mongolia section of Yellow River, China were discussed in order to estimate their distribution and pollution level. The measured metals in the sediments were found be in the range of Cu 10.28~45.54, Fe 18, 460.00~41, 880.00, Mn 448.90~919.83, Ni 8.52~67.39, Zn 60.93~149.40, Cr 65.69~149.67, Pb 0.50~19.98 and Cd 0.23~4.36 mg kg–1. The mean values of the heavy metal contents were arranged in the following decreasing order: Fe > Mn > Cr > Zn > Ni > Cu > Pb >Cd. Significant positive correlations were observed between the concentrations of Cu, Fe, Mn and Zn. Common sources and the identical behavior are observed in these heavy metals. PCA extracted two components with eigenvalues explaining 62.190% of the total variance. Cu, Fe, Mn, Zn, Cr had the natural origin controlled by the first factor. Anthropogenic causes are major sources of Pb and Cd. Ni could be affected by natural geological background and human activity. The higher values of Geo-accumulation index, enrichment factor, and PLI of Cr were attributed principally to anthropogenic activities. Fe and Zn did not lead to pollution. The Sediment contamination grade from the Inner Mongolia section in upstream of Yellow River was 0~1, belonging to from unpolluted to moderately polluted. [ABSTRACT FROM AUTHOR]

In this work, a Mg–Zn–Ca magnesium matrix nanocomposite containing nano-sized TiC particles was firstly processed by multidirectional forging (MDF). With increasing the forging temperature from 230 to 310 °C for 1 MDF pass or the number of MDF passes at 270 °C, both volume fractions and average sizes of recrystallized grains increased. The average sizes of precipitated MgZn2 phases increased with the increase in either the initial forging temperature or MDF passes, and the volume fractions gradually decreased with increasing the initial forging temperature or decreasing the MDF passes. With decreasing the initial MDF temperature, thermal expansion mismatch strengthening slightly decreased while fine-grain strengthening and Orowan strengthening gradually increased, resulting in a gradual increased yield strength. The elongation of the present nanocomposite gradually increased from 8.2% after 1 MDF pass to 22.7% after 6 MDF passes, while both yield strength and ultimate tensile strength did not change significantly. This could be ascribed to that although the fine-grain strengthening gradually reduced, there was no significant change in the Orowan strengthening caused by MgZn2 phases with increasing the number of MDF passes. [ABSTRACT FROM AUTHOR]

Background and purpose: Studies on using antiplatelet agents for secondary prevention in ischaemic stroke patients with renal dysfunction are limited. The Taiwan Stroke Registry database was used to compare the efficacy of antiplatelet agents. Methods: From the Taiwan Stroke Registry data, 39 174 acute ischaemic stroke patients were identified and were classified into three groups by antiplatelet agent: aspirin, clopidogrel and dual antiplatelet therapy (DAPT) with a combination of aspirin and clopidogrel. The re‐stroke incidence and 1‐year mortality were stratified by estimated glomerular filtration rate (eGFR) levels at admission: ≥90, 60–89 and <60 ml/min/1.73 m2 or on dialysis. Results: Compared to the aspirin group, the re‐stroke differences were not statistically significant for the clopidogrel group [adjusted subhazard ratio 0.95, 95% confidence interval (CI) 0.84–1.08] and the DAPT group (adjusted subhazard ratio 1.03, 95% CI 0.77–1.39) after controlling for the competing risk of death. The mortality rate increased as the eGFR level declined. In addition, compared to patients taking aspirin, there was no statistically significant difference in overall 1‐year mortality for the clopidogrel group (adjusted hazard ratio 1.11, 95% CI 0.95–1.29) and for the DAPT group (adjusted hazard ratio 1.01, 95% CI 0.67–1.54). The results were consistent in different subgroups stratified by eGFR levels. Conclusions: There was no difference in the risks of recurrent stroke and 1‐year mortality amongst ischaemic stroke patients with or without renal dysfunction receiving antiplatelet agents with aspirin, clopidogrel or dual agents with a combination of aspirin and clopidogrel, regardless of their renal dysfunction status. [ABSTRACT FROM AUTHOR]

Abstract: A 10‐week growth trial was run to evaluate effects of myo‐inositol (MI) on growth performance, haematological parameters, antioxidative capacity and salinity stress tolerance of Litopenaeus vannamei. Six practical diets supplemented with graded levels of MI (designated as MI0, MI600, MI1200, MI2400, MI 3600 and MI4800 for 448.8, 974.2, 1568.0, 2810.6, 3835.5 and 4893.6 mg/kg diet, respectively) were fed to six replicate groups of L. vannamei (mean initial body weight 0.63 ± 0.00 g). The results showed that significant increment of growth performance was observed in shrimp fed MI600 diet than those fed MI1200 diet. Lipid concentration in whole body of the shrimp fed MI600 diet was significantly increased. Shrimp fed MI0 diet had lower total protein (TP) as compared to shrimp fed the MI‐supplemented diets (except MI4800 diet). In general, lower activities of antioxidant enzymes and higher malondialdehyde (MDA) content in haemolymph and hepatopancreas were recorded in shrimp fed MI0 diet, compared to those fed the MI‐supplemented diets. Reduced survival after 7‐h salinity stress was present in shrimp fed MI0 diet as compared to those fed MI4800 diet. Dietary MI requirement for glutathione peroxidase activity of L. vannamei was 2705 mg/kg diet. [ABSTRACT FROM AUTHOR]

Cast iron with good mechanical and thermal combination property is preferred material for the cylinder head of high power density diesel engine. Interface between graphite and matrix should play a key role in thermal conductivity of cast iron. However, it is difficult to measure the interfacial contact thermal conductance (ICTC) between graphite inclusion and matrix in cast iron. In this paper, a modeling experimental sample containing a macroscopic interface is designed and ICTC can be estimated with the aid of finite element (FE) calculation. At last the effect of ICTC on the thermal conductivity of cast iron is assessed according to the change of metallographic FE simulation results before and after considering ICTC. Results show that the magnitude of ICTC is between 1.0 × 105 and 2.0 × 105 W m−2·K on the whole. The interface makes the theoretical thermal conductivity of cast iron drop down 34.6%. [ABSTRACT FROM AUTHOR]

(Ti, Zn)-co-doped Bi0.97Nd0.03FeO3(BNFTZ) thin films with different thicknesses were prepared directly on indium tin oxide/glass substrates deriving from the precursor solutions with different solution concentrations. The X-ray diffraction, scanning electron microscopy and insulating/ferroelectric/dielectric measurements were utilised to characterise the BNFTZ thin films. Both BNFTZ thin films with the thicknesses of 160 and 320 nm are crystallised into phase-pure perovskite structure without second phase. Compared to the film of 160 nm, a lower leakage current can be obtained in BNFTZ film of 320 nm due to due to its denser microstructure with smaller grain size. The film with 320 nm thickness possesses a high energy-storage efficiency of 87%, which can be ascribed to the slimP–Eloop. At 100 kHz, the film of 320 nm owns lower dielectric constant (~91) and dissipation factor (~0.10). The possible contributions are discussed to explain the difference in the related performances for BNFTZ thin films with different thicknesses. [ABSTRACT FROM AUTHOR]

Concrete cover separation is a common failure mode of RC beams strengthened with a fiber-reinforced polymer (FRP) plate externally bonded to the tension face (FRP-plated RC beams). This failure mode initiates at the critical plate end and then propagates at the level of steel tension reinforcement in the direction of increasing moment. Plate-end anchorage by FRP U-jackets has been specified in some design guidelines as a mitigation measure to delay or suppress concrete cover separation, although its effectiveness is far from clear. This mitigation method is more attractive than other options because the same strengthening material is used and the installation procedure is simple. This paper presents the first systematic experimental study on the use of FRP U-jackets for mitigating plate-end concrete cover separation failure, with particular attention to the effect of inclination angle between the U-jacket and the beam axis. A total of 10 fullscale FRP-plated RC beams were tested. The test results show that both the load-carrying capacity and the ductility of an FRP-plated RC beam can be significantly enhanced by FRP U-jacketing at the critical plate end. Inclined U-jacketing at 45° to the beam axis was found to be much more effective than vertical U-jacketing (i.e., at 90° to the beam axis) in mitigating plate-end cover separation failure. [ABSTRACT FROM AUTHOR]

A recently proposed technique for the recycling of concrete is to directly reuse large pieces of coarsely crushed demolition concrete (referred to as recycled concrete lumps or RCLs) with fresh concrete in new construction. This novel recycling process is simpler and more cost-effective than the traditional way of recycling concrete as aggregates. The resulting concrete, referred to as compound concrete in this paper, features greater heterogeneity, especially when the fresh and the recycled concretes have rather different strengths. The interfaces between RCLs and fresh concrete, as internal weaknesses, may also compromise the performance of the compound concrete. One possibility to improve the properties of this compound concrete is to supply it with a substantial amount of confinement as may be available in concrete-filled FRP tubes, which are attractive as columns in corrosive environments. This paper therefore presents and interprets the results of an experimental study on the compressive behavior of FRP confining tubes filled with compound concrete. The influences of various parameters, such as the mix ratio and the strength ratio between the old and the fresh concretes as well as the FRP tube thickness, are investigated. The test results indicate that with a significant level of confinement, the ultimate axial stress and the ultimate axial strain of the compound concrete containing RCLs are comparable with those of the fresh concrete, regardless of the strength of the old concrete. This conclusion is important as it means that the weaknesses of compound concrete containing RCLs can be largely eliminated through lateral confinement. The applicability of an accurate stress-strain model previously developed for FRP-confined normal concrete to FRP-confined compound concrete with RCLs is also examined. [ABSTRACT FROM AUTHOR]

An infiltration crystallisation concentrating agent was prepared using recycled concrete micropowder from construction waste as main material with instant sodium silicate, aluminium stearate and other active ingredients. The optimum mixture ratio and self-healing effect of the concentrating agent were studied. Compression experiments conducted in the laboratory were terminated when penetrating cracks appeared on the specimen. The specimen was then subjected to standard curing for 28 days after which, second pressure of the specimen was tested. Pore structures of the specimen pre-and post-curing were also tested. The self-healing property of the concentrating agent was characterised using the above comparative analysis. The results indicated that the concentrating agent possessed good self-healing capabilities. The optimum mixture ratio of the self-regenerating infiltration crystallisation concentrating agent is cement, 55%; quartz sand, 25%; instant 5% sodium silicate, 5%; aluminium stearate, 1%; recycled concrete micropowder, 20%; CaO, 8%; water-cement ratio, 0.6 and grey sand ratio, 1/3. [ABSTRACT FROM AUTHOR]

This review outlines the specific methods and concepts of self-healing that have been adopted locally and globally. Based on the need for manual intervention, these methods and concepts of self-healing can be classified as passive or active. The theory of biological self-healing concrete is also analysed. The mechanism by which the diagenesis of biomaterials triggers and promotes self-healing in the tiny cracks of cement is explained. This paper introduces a biological multiple-triggered-switch scheme for the self-healing of cement-based cracks. The role of this mechanism in the continued and feasible self-healing of cracks is analysed. [ABSTRACT FROM AUTHOR]

Evaluations of both macroscopic and mesoscopic strengths of materials have been the topic of a great deal of recent research. This paper presents the results of a study, based on the Walraven equation of the production of a mesoscopic random aggregate structure containing various rubber contents and aggregate sizes. On a mesoscopic scale, the damage mechanism in the rubber concrete and the effects of the rubber content and aggregate-mortar interface on the rubber concrete’s compressive resistance property were studied. The results indicate that the random aggregate structural model very closely approximates the experimental results in terms of the fracture distribution and damage characteristics under uniaxial compression. The aggregate-mortar interface mechanical properties have a substantial impact on the test sample’s strength and fracture distribution. As the rubber content increases, the compressive strength and elastic modulus of the test sample decrease proportionally. This paper presents graphics of the entire process from fracture propagation to structural failure of the test piece by means of the mesoscopic finite-element method, which provides a theoretical reference for studying the damage mechanism in rubber concrete and performing parametric calculations. [ABSTRACT FROM AUTHOR]

As in all RNA viruses, influenza viruses change and mutate constantly because their RNA polymerase has no proofreading ability. This poses a serious threat to public health nowadays. In addition, traditional pathogen-based detection methods may not be able to report an infection from an unknown type or a subtype of virus if its nucleotide sequence is not known. Because of these factors, targeting host microRNA signatures may be an alternative to classify infections and distinguish types of pathogens as microRNAs are produced in humans shortly after infection. Although this approach is in its infant stage, there is an urgent need to develop a rapid reporter assay for microRNA for disease control and prevention. As a proof of concept, we report herein for the first time a non-PCR MARS (MicroRNA-RNase-SPR) assay to detect the microRNA miR-29a-3p from human subjects infected with influenza virus H1N1 by surface plasmon resonance (SPR). In our MARS assay, RNase H is employed to specifically hydrolyze the RNA probes immobilized on the gold surface where they hybridize with its cognate target cDNAs miR-29a-3p, where it was formed from reverse transcription with mature miR-29a-3p specific stem-looped primers. After the digestion of the RNA probe by RNase H, the intact cDNA was released from the RNA–DNA hybrid and bound to a new RNA probe for another enzymatic reaction cycle to amplify signals. With assay optimization, the detection limit of our MARS assay for miR-29a-3p was found to be 1 nM, and this new assay could be completed within 1 hour without thermal cycling. This non-PCR assay with high selectivity for mature microRNA provides a new platform for rapid disease diagnosis, quarantine and disease control. [ABSTRACT FROM AUTHOR]

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This paper presents a novel harmonic-suppressed microstrip open-loop resonator bandpass filter with the different transmission line characteristic impedance of the feed line and open-loop resonator for wireless local area network (WLAN) application. To improve the stopband rejection of the filter, the dumbbell-shape defected ground structure (DGS) are applied under the feed lines to suppress the harmonics and the equivalent parameters extraction formulations of double-dumbell-shaped DGSs are the first to proposed. The bandpass filter with center frequency of 2.44 GHz were designed and fabricated on a TLX substrate with thickness of 1 mm and dielectric constant of 2.55. Measurement results show the filter has a wide stopband characteristic with 30 dB attenuation up to 7.5 GHz and only has an –1.23 dB insertion loss while it is a little larger than the conventional one. The measured results are in good agreement with the simulated results. It can be widely used for WLAN application. [ABSTRACT FROM AUTHOR]

A novel complementary split-ring resonators (CSRRs) DGS has been investigated theoretically and experimentally. The proposed DGS provides excellent performance in terms of double resonant property, ripple in the pass band, sharp selectivity at the cut-off frequency and spurious free wide stop band. A LPF using the proposed DGS unit is fabricated and three cascaded DGSs are employed in another LPF to obtain very wide reject band. The measured results illustrated the excellent performance. [ABSTRACT FROM AUTHOR]

This paper presents a novel harmonic-suppressed microstrip open loop resonator bandpass filter with defected ground structure (DGS) for wireless local area network (WLAN) application. To improve the stopband rejection of the filter, DGSs are applied under the feed lines to suppress the harmonics. The bandpass filter with center frequency of 2.44 GHz is designed and fabricated on a TLX substrate with thickness of 1 mm and dielectric constant of 2.55. By using two dumbbell-shape DGSs the filter has a wide stopband characteristic with attenuation -25 dB up to 8 GHz and has an -1.25 dB insertion loss while it demonstrates a little larger than the conventional one. The measured results agree well with the simulation results. The proposed filter is found to possess low in-band insertion loss and high out-band suppression, making it suitable in WLAN application. [ABSTRACT FROM AUTHOR]

Modified current model has been developed to more accurately model the current-voltage characteristics of GaAs pHEMTs over a wide range of temperature. In particular, the modeling accuracy of knee, saturation and subthreshold regions has been greatly improved. These results are achieved by introducing the polynomial expression on the bias conditions. The verification is performed by fabricated pHEMTs at different temperature. Good agreement is obtained. [ABSTRACT FROM AUTHOR]

A dielectric half space model is introduced into the simulation of the scattering from ships on sea surface, which is excited by a plane wave. With the acceleration of Generalized Forward-Backward (GFB) method, the electromagnetic (EM) scattering can be simulated quickly in high precision. A High Resolution Range Profile (HRRP) is formed with the results computed in half space model, and the HRRP of ship on ocean in different aspects are discussed. As showed in the simulation, the model predicted in the paper is proved more valid and accurate than free space model. [ABSTRACT FROM AUTHOR]

One of the most critical hardware components for the performance of the Ground-Penetrating Radar (GPR) system is the antenna and the resistive loaded antenna is one of common antennas used in the GPR system. The authors extend the Wu-King linear current distribution to the double exponential current distribution, modify the inaccurate part of the Wu-King loading profile and deduce an improved resistive loading profile with high efficiency. The broadband performance of the improved resistive loading profile has been studied; the concept of lengthening coefficient is created and the optimum parameter designing curve of the antenna is provided. Numerical calculation shows that the maximum bandwidth and efficiency of antenna can be achieved with the improved loading profile simultaneously. The impedance bandwidth is as high as 40:1, which is much greater than the 3:1 bandwidth of Wu-King distribution when the voltage standing wave ratio is below 3. It exhibits better efficiency and bandwidth than Wu-King loading profile. The loading profile can reduce the late-time ringing, enhance the pulse radiation characteristics and be widely applied to other resistive loading antenna for GPR applications. [ABSTRACT FROM AUTHOR]

A pair of single chain Fv fragment (scFv) fusion proteins were constructed and characterized. Antibody chips using the pair were designed for sensitive detection of prion protein. Phage displayed antibody library was synthesized by immunizing mice with thioredoxin-mature bovine prion fusion protein (TrxA-bPrPc). After five rounds of panning against recombinant bovine prion protein (rb-PrPc) and ELISA test, two positive clones with high affinity to rb-PrPc, named Z163 and Z186, were obtained. They were conjugated with a linker-streptavidin binding protein (SBP) or human IgG1 constant fragment (Fc) to form the scFv fusion protein pair Z186-L-SBP/Z163-Fc. Western blot experiments showed that the scFv fusion pair specifically interacted with the line epitopes of the protease resistant core region bPrP27-30. Surface plasmon resonance (SPR) sensorgrams revealed that the equilibrium dissociation constants of the interactions with rb-PrPc were 3.24×10-8 M, 8.82×10-8M, and 8.10×10-9 M for Z186-L-SBP, Z163, and Z163-Fc, respectively. All binding reactions followed rapid association and slow dissociation kinetics. As a detection pair, Z186-L-SBP functioned as a capture probe and was immobilized on the streptavidin coated slides to form reactive layer of the antibody chip, and Z163-Fc labeled with fluorescence dye Cy3 functioned as a detection probe generating fluorescence signal. The antibody chip could detect existence of rb-PrPc with detection limit of 1 pg/ml. [ABSTRACT FROM AUTHOR]

When the airborne fire control radar operates with the high pulse-repetition frequency (PRF) in the frequency-modulated ranging mode, the range measurement is ambiguous. Here, the problem of target range estimation and ambiguity resolving is converted to the problem of static multiple models estimation and decision. Frequency and pseudo-range measurements are used to update each model of the target with the probabilistic data association and tracking filter. The method to select the PRF used to detect the target is also suggested according to the state estimates of the survived models. Simulation results demonstrate the improved accuracy and convergence when compared with the conventional methods. [ABSTRACT FROM AUTHOR]

Electron diffraction spots splitting into three is an unusual phenomenon. Based on the analysis of crystal structure, the splitting is believed due to some neighboring crystal cells grow along a small angle θ, rather than along a parallel direction as in general case. When a crystal grows along two neighboring boundaries with a small angle, the distance of the two boundaries increases as well. When the distance of the two boundaries reaches as large as a cell constant, a new cell will grow in the site, which is called an edge dislocation. According to the geometric relation of the reciprocal space, small angle grain boundaries can be calculated from the corresponding splitting spots. In this work, two small angles θ are determined to be -2.5° and 3.0°, respectively. Obviously, the grain with small angle grain boundaries has a curved surface and the curvature of the surface is determined by the density of the edge dislocation. The corresponding parameters of the edge dislocation are calculated. Both the edge dislocation and the neighboring cells growing along a small angle are a growing mechanism of YBa[sub 2]Cu[sub 3]O[sub y] and this mechanism is responsible for the curved grain surface. [ABSTRACT FROM AUTHOR]

The transport critical current densities, J[sub c], of superconducting (Bi, Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x]/Ag tapes were measured before and after employing a special radiation technique, which leaves the grain boundary properties largely unaffected. We identify two regions separated by a temperature dependent crossover field H[sub gb-p]. In the low field region, J[sub c] is limited by the transport currents across the grain boundaries, which remain unchanged after irradiation. Above H[sub gb-p], J[sub c] is limited by flux pinning. In this field region, the artificial defects optimize flux pinning and enhance J[sub c]. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]