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In order to ensure the filling integrity of complex counter-gravity casting and improve metallurgical quality, it is necessary to shorten the filling time while avoiding air entrainments. To address this contradiction, a novel nonlinear pressurization method was proposed in this study. Through systematically analyzing the relationship between critical gating velocity and stable filling height, a criterion for iterative calculation of nonlinear pressurization curve was established, and an empirical expression between nonlinear pressurizing speed and the filling height was obtained. Based on the empirical expression, a nonlinear pressurization curve can be designed according to the casting structures and initial pressurizing speeds. The above nonlinear pressure curve design method was validated through water filling experiments. It was proved that the nonlinear pressure curve can shorten the filling time while avoiding air entrainments. It provides important processing control method for improving the low-pressure casting performance of complex castings. [ABSTRACT FROM AUTHOR]

Induction skull melting (ISM) technology could melt metals with avoiding contamination from crucible. A long-standing problem of ISM is that the low charge energy utilization and inhomogeneous fields have obstructed its application in many critical metal materials and manufacturing processes. The present work investigated the problem through the structure optimization strategy and established a numerical electromagnetic-field model to evaluate components' eddy current loss. Based on the model, the effect of crucible and inductor structure on charge energy utilization, etc. was studied. Furtherly, the charge energy utilization was increased from 27.1 to 45.89% by adjusting the system structure. Moreover, structure modifications are proposed for enhancing electromagnetic intensity and uniformity, charge soft contact and uniform heating. The work constructed a basis for framing new solutions to the problem through ISM device structure optimization. [ABSTRACT FROM AUTHOR]

Superparamagnetic iron oxide (SPIO) nanoparticles play an important role in mediating precise and effective magnetic neurostimulation and can help overcome limitations related to penetration depth and spatial resolution. However, nanoparticles readily diffuse in vivo, decreasing the spatial resolution and activation efficiency. In this study, we employed a microfluidic means to fabricate injectable microhydrogels encapsulated with SPIO nanoparticles, which significantly improved the stability of nanoparticles, increased the magnetic properties, and reinforced the stimulation effectivity. The fabricated magnetic microhydrogels were highly uniform in size and sphericity, enabling minimally invasive injection into brain tissue. The long-term residency in the cortex up to 22 weeks and the safety of brain tissue were shown using a mouse model. In addition, we quantitatively determined the magneto-mechanical force yielded by only one magnetic microhydrogel using a video-based method. The force was found to be within 7–8 pN under 10 Hz magnetic stimulation by both theoretical simulation and experimental measurement. Lastly, electrophysiological measurement of brain slices showed that the magnetic microhydrogels offer significant advantages in terms of neural activation relative to dissociative SPIO nanoparticles. A universal strategy is thus offered for performing magnetic neuro-stimulation with an improved prospect for biomedical translation. [ABSTRACT FROM AUTHOR]

The development of novel catalysts for the synthesis of cyclic carbonates under mild conditions remains a challenge. Herein, we designed the strategy of immobilizing DBU-based ionic liquid on mesoporous SBA-15 (DBU@SBA-15), due to the cooperative effect between silanol and bromide anion, DBU@SBA-15 exhibits high CO2 catalytic performance under solvent-free and metal-free and additive-free conditions. Typically, the yield of chloropropene carbonate was close to 100% from the reaction of epichlorohydrin and CO2 within 12 h at 80 °C and 2 MPa. Notably, the product yield could achieve 64.8% even at ambient pressure, and DBU@SBA-15 was recycled four times without significant loss of catalytic activity. Additionally, DFT studies revealed that the nucleophilic effect and the strong hydrogen bond together promote the ring-opening of epoxides, which was consistent with the possible reaction mechanism proposed based on experiments. [ABSTRACT FROM AUTHOR]

'Magic-angled' structure currently attracts increasing attention from condensed matter physics due to its amazing performance in superconductivity of graphene. The similar pattern formation of nanoparticles will bring about novel physics in nanoscale that causes the next generation nanodevices. However, it remains a challenging task to acquire such patterns by self-assembly process. In this article, we reported a Moiré interference pattern formation of magnetic nanoparticles regulated by a rotational magnetic field. The colloidal concentration, the strength, and the frequency of magnetic field were found to affect the pattern formation. The mechanism lied in a two-step process. First, the magnetic nanoparticles formed bilayers of superlattice driven by hydrophobic interaction of interfacial self-assembly. Then, the bilayers of superlattice yielded asynchronous rotational displacement resulting from the magnetic force so that the Moiré interference pattern of nanoparticles formed. This fabrication methodology based on the field-controlled self-assembly provided a novel and simple means to get 'magic angled' structures in nanoscale that will enrich the physical understanding of nanotechnology. [ABSTRACT FROM AUTHOR]

With the rise of neural network, deep learning technology is more and more widely used in various fields. Federated learning is one of the training types in deep learning. In federated learning, each user and cloud server (CS) cooperatively train a unified neural network model. However, in this process, the neural network system may face some more challenging problems exemplified by the threat of user privacy disclosure, the error of server's returned results, and the difficulty of implementing the trusted center in practice. In order to solve the above problems simultaneously, we propose a verifiable federated training scheme that supports privacy protection over deep neural networks. In our scheme, the key exchange technology is used to remove the trusted center, the double masking protocol is used to ensure that the privacy of users is not disclosed, and the tag aggregation method is used to ensure the correctness of the results returned by the server. Formal security analysis and comprehensive performance evaluation indicate that the proposed scheme is secure and efficient. [ABSTRACT FROM AUTHOR]

Duck circovirus (DuCV) is widespread across the world and causes feather disorders in young ducks. It was identified as the causative pathogen of duck beak atrophy and dwarfism syndrome and primary sclerosing cholangitis. In this study, we aimed to establish a TaqMan-based real-time PCR assay to detect DuCV. The primers and probe were designed based on the conserved region of the DuCV Rep gene. After optimizing the reaction conditions, the minimum virus detection limit of the designed PCR technique was 39.4 copies/μL, 100 times that of conventional PCR (cPCR). No cross-reaction with six other common duck viruses was observed. The intra- and inter-assay variations were less than 1%. The detection rate of DuCV-positive clinical samples using TaqMan-based real-time PCR was higher than that using SYBR Green-based real-time PCR and cPCR. Collectively, these results showed that the established TaqMan-based real-time PCR detected DuCV with high sensitivity and specificity, and significant repeatability, making it suitable for clinical use. Hence, it may be used as a novel tool for the diagnosis and epidemiological investigation of DuCV. [ABSTRACT FROM AUTHOR]

Since both feline parvovirus (FPV) and feline bocavirus (FBoV) can cause diarrhea in cats, it is difficult to distinguish them clinically. This study aimed to develop a SYBR Green I-based duplex real-time polymerase chain reaction (PCR) assay for distinguishing FPV and FBoV-1 on the basis of the melting temperature of the PCR product. A total of 132 fecal samples from different domestic and feral cats were collected, and the results of SYBR Green I-based duplex real-time PCR assay were compared with those of the traditional PCR assay for a comprehensive evaluation. The melting temperatures were found to be 86 °C and 77.5 °C for FBoV-1 and FPV, respectively, and no specific melting peaks for other non-targeted feline viruses were observed. The data obtained from this assay had a good linear relationship; the detection limits of FPV and FBoV-1 were 2.907 × 101 copies/μL and 3.836 × 101 copies/μL, respectively. In addition, the experiment exhibited high reproducibility. The positive detection rates of the SYBR Green I-based duplex real-time PCR assay for FPV and FBoV-1 were 16.67% (22/132) and 6.82% (9/132), respectively, and the positive detection rate for co-infection with FPV and FBoV-1 was 3.03% (4/132). This result was much more sensitive than that of the traditional PCR method. Thus, the developed SYBR Green I-based assay is a sensitive, rapid, specific, and reliable method for the clinical diagnosis of FPV and FBoV-1 and can provide technical support for the simultaneous detection of co-infection with these viruses in the future. [ABSTRACT FROM AUTHOR]

Recently, a novel duck-origin goose parvovirus (N-GPV) was reported to cause short beak and dwarfism syndrome in ducks. In this study, we performed complete genome sequencing and analyzed three different duck-derived parvoviruses that infected different breeds of ducks. Phylogenetic trees based on gene sequences indicated that they were classical goose parvovirus (C-GPV), Muscovy duck parvovirus (MDPV), and N-GPV. Furthermore, potential recombination events were found. These results improve our understanding of the diversity of duck-derived parvoviruses in Anhui province, eastern China, and provide a reference for the prevention of associated diseases. [ABSTRACT FROM AUTHOR]

Feline bocavirus 1 (FBoV-1) may be associated with diarrhea in cats. In this study, a SYBR Green I-based quantitative polymerase chain reaction (qPCR) assay was established to detect FBoV-1. The melting curve showed a single melting peak at 83.0 ℃. The results of sensitivity showed that the detection limit of the qPCR was 3.87 × 101 copies/μL. Of note, the detection limit of the conventional polymerase chain reaction (cPCR) was 3.87 × 103 copies/μL. The highest intra-assay and inter-assay coefficients of variation (CV%) were 0.98% and 1.42%, respectively. The positive detection rate of 128 clinical samples using the qPCR and the cPCR was 7.0% (9/128) and 4.7% (6/128), respectively. Taken together, these results indicated that the established qPCR assay has good sensitivity, high specificity, and good reproducibility. Therefore, it could provide support for the rapid and efficient clinical detection of FBoV-1. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to prepare tosufloxacin tosylate (TFLX) and hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complexes by solution-enhanced dispersion with supercritical CO2 (SEDS) and optimize process parameters, in vitro dissolution evaluation, and determination of inclusion sites. Methods: The effects of operating pressure, operating temperature, drug concentration, and solution flow rate on the particle size and morphology of the inclusion complex were analyzed by a single factor design experiment. The SEDS-prepared inclusion complex was characterized by TG/DSC, XRD, SEM, FT-IR, 1H NMR, 2D-ROESY, and MD and measured for in vitro dissolution, solubility, and antibacterial activity. Results: The optimum drug concentration was 40 mg/mL and pressure 16 MPa, temperature 35 °C, and solution flow rate 1 mL/min; under this condition, the mean particle size of the inclusion complex was 1.91 μm. All characterization results confirmed the formation of an amorphous inclusion complex and the sites where TFLX and HP-β-CD bind through the H-bond were located on the aromatic B ring, pyrrolidine, and naphthyridine ring protons. Furthermore, the solubility of the inclusion complex (489.87 μg/mL) was significantly higher than that of TFLX, and the dissolution rate of TFLX increased from the initial 13.99 to 61.04% in ultrapure water. In vitro study showed that the inclusion complex maintained the antibacterial effect of TFLX. Conclusion: TFLX/HP-β-CD inclusion complex prepared by manipulating SEDS process conditions could significantly improve the dissolution and solubility of the water-insoluble TFLX. [ABSTRACT FROM AUTHOR]

The creep behaviors of the amorphous phase in a CuZr-based bulk metallic glass composite (BMGC) are studied by nano-indentation. Samples fabricated via higher cooling rates are found to exhibit more prominent creep, but a smaller shear viscosity. The volume of the shear transformation zones (STZs) in the amorphous phase calculated based on a cooperative shear model increases with the cooling rate. The evolution of excess free volume created during creep deformation is clarified. A looser atomic arrangement leads to a larger STZ volume, thus facilitating creep deformation. This study gives a better understanding of the deformation behaviors of the amorphous phase in BMGCs. [ABSTRACT FROM AUTHOR]

This study aimed to explore the phylogenetic and molecular characteristics of feline astrovirus. A total of 33 fecal samples of domestic cats with or without diarrhea were collected from the Anhui province, and two positive samples were detected. The complete genome and ORF2 of the two strains were sequenced and phylogenetically analyzed. AH-1-2020 and AH-2-2020 displayed 83.4% homology, and their homologies with other reference strains were 75.3%–83.4% and 83.4%–95.0%, respectively. Phylogenetic tree analysis revealed that all strains could be classified into three different clusters; therefore, the mean amino acid genetic distances (p-dist) among the three clusters were estimated. The results suggested that the two strains and other FeAstV strains were grouped into three genotypes, with AH-1-2020 belonging to a novel genotype. High similarity was observed (65.9%–66.5% nucleotide identity and 63.8%–64.8% amino acid identity) in ORF2 between porcine astrovirus type 1 and AH-1-2020. Furthermore, inter-specific recombination between porcine astrovirus type 1 and FeAstV was observed. We, therefore, inferred that inter-specific transmission may exist between pigs and cats; however, further studies are required to verify this. This is the first report on the genetic characterization and phylogenetic analysis of FeAstVs in the Anhui province and would further the current understanding of the genetic diversity and epidemiology of FeAstVs. [ABSTRACT FROM AUTHOR]

Inosine monophosphate (IMP) was considered to be an important component of meat flavor and an important indicator for evaluating the quality of meat products. This paper developed a novel dual-enzyme biosensor for the quantitative detection of inosinic acid to assess meat quality. Using the conductivity of MXene materials and the ability of Au@Pt nanoflowers to catalyze the oxidation of H2O2, a dual-enzyme biosensor was assembled and prepared for sensitive and rapid detection of IMP. The MXene-Ti3C2Tx material had 2D nanostructure similar to that of graphene, as well as metal conductivity and good biocompatibility. MXene was used as a carrier for 5′-nucleotidase and xanthine oxidase, with good biological environment and stable microenvironment. Bimetallic nanoflowers with a core-shell structure had better ability to catalyze H2O2 than the single metal. The double-enzyme hydrolyzed IMP to produce the H2O2. The Au@Pt nanoflowers of the sensor can catalyze the decomposition of H2O2, which causes electron transfer to produce current change. Therefore, the content of IMP is indirectly obtained by monitoring the current change. The results showed that the linear range of the double-enzyme biosensor was 0.04~17 g L−1, the correlation coefficient was 0.9964, and the detection limit was 2.73 ng mL−1. The biosensor had great reproducibility and stability. Compared with high-performance liquid chromatography, biosensors could quickly and accurately detect the content of inosine monophosphate in meat, and provided a better method to detect the quality index of meat products. [ABSTRACT FROM AUTHOR]

High-temperature oxidation behavior of molten Mg-Nd-Zr in the pyrolysis atmosphere of resin-bind sand mold was investigated. The results showed that pouring temperature higher than 1023 K would sharply increase the ignition risk of melt in mold. The oxide formed on Mg-Nd-Zr melt below 973 K consists of two layers: mainly MgO for outer layer; mixture of MgO and Nd2O3 for inner layer. The inner oxide mixture layer played an essential role in the protection of Mg-Nd-Zr matrix. Based on the experimental results and thermodynamic analysis, the oxidation process containing three stages was proposed. Nd- and Zn-enriched zone was found at the subsurface of oxide scale, without the enrichment of Zr. DICTRA calculation results indicated that this phenomenon was caused by the depletion of Mg and up-hill diffusion of Zr. Thus, Zr showed limited protection to the melt in long-term oxidation. [ABSTRACT FROM AUTHOR]

A wide variety of industrial applications require Al-Zn-Mg-Cu alloys with high strength and ductility. However, Zn-rich Al-Zn-Mg-Cu alloys prepared by rapid solidification methods usually show excellent strength but poor formability, which restricts their wide application in complex forming. In this study, we developed a new deformation method for the spray-deposited Zn-rich Al-Zn-Mg-Cu alloy to avoid crack formation and achieve isotropic properties. The microstructure evolution and crystallographic textures were analyzed and compared with the results of a normal deformation process. Crack-free forgings with the ultimate tensile strength (UTS), yield strength (YS) and elongation of 727 ± 5 MPa, 690 ± 3 MPa, 5.0 ± 0.7% along the radial direction and 735 ± 2 MPa, 693 ± 3 MPa, 6.3 ± 0.2% along the tangential direction were finally obtained. The improvement in the mechanical properties can be attributed to the larger amount of subgrains and substructures generated in the canned deformed alloy. The results of this study show excellent advantages and potential application prospects of the canned deformation to hard-deformed Al-Zn-Mg-Cu alloys. [ABSTRACT FROM AUTHOR]

The oxidation behaviors of molten WE43 (Mg-4.32Y-2.83Nd-0.41Zr, wt%) in resin-sand mold atmosphere were systematically investigated. X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy analyses were employed to identify the phase compositions and microstructures of surface oxide scale. The initial oxide scale characterized by a three-layer structure mainly consisted of MgO, Y2O3, and ZrO2 and then transformed to Y2O3 layers covered by porous MgO after holding at high temperatures. CALPHAD method was used to analyze the oxidation process, and the calculated phase diagrams agreed well with the experimental results. A selective oxidation model was established based on thermodynamic and kinetic analysis to describe the structure transformation of oxide scale in detail. The initial oxidation was controlled by inward diffusion of oxygen due to the protection of surface Y2O3. However, the oxide scale was not protective after long-term oxidation or at temperatures higher than 1073 K due to the oxide fracture, which can be attributed to the increase in stress caused by inner Y2O3 layer growth. Based on experimental results, the oxide growth stress parameter C was estimated to be 0.0013 and 0.0026 for 1023 and 973 K, respectively. This work reveals the underlying oxide growth and fracture mechanisms of molten Mg-Y alloy in mold, and provides guidance for preventing the ignition of magnesium alloys during casting processes. [ABSTRACT FROM AUTHOR]

The stimulation of plant growth and biomass accumulation by elevated CO2 may be limited by soil nitrogen (N) availability. However, our understanding of the response of soil N cycling to elevated CO2 and when progressive N limitation occurs remains limited. Here, we used an open top chamber experiment to examine the effects of 10 years of elevated CO2 on ecosystem carbon (C) and N dynamics in a Quercus mongolica (oak) dominated system in northeastern China. Elevated CO2 increased oak biomass, C and N stocks and C/N by 26.4, 26.2, 16.5 and 8.6% respectively, which suggests increased plant N demand. Soil gross N mineralization, re-mineralization of microbial N and nitrification were accelerated likely due to increased photosynthesis (by 34.9%) and microbial biomass (by 24.2%) under elevated CO2. Thus, the supply of soil available N can sustain the tree growth stimulated by elevated CO2, and to date progressive N limitation has not happened. Nevertheless, both the annual increase of oak biomass, C and N stocks and C/N ratio and the seasonal variations of soil available N and microbial N concentrations, and net N transformation rates indicated that gradual N deficiency may be occurring and the CO2 fertilization effect has weakened with increasing treatment duration. [ABSTRACT FROM AUTHOR]

The comprehensive and reasonable mechanisms of Cl-initiated oxidation of ethyl acrylate (EA) have been proposed by computing at the M06-2X/6-311++G(3df, 2p)//M06-2X/6-31+G(d, p) level of theory. The primary reaction includes eight channels: two Cl additions and six H abstractions. Comparing all calculated results, the reactions of Cl addition are easier to occur than those of H abstraction. However, the hydrogen abstraction from the -CH and -CH groups cannot be ignored. Based on the Rice-Ramsperger-Kassel-Marcus (RRKM) theory, the rate constants are determined employing the MESMER program. The calculated total rate constant (at 298 K and 760 Torr) is 1.80 × 10 cm molecule s and shows negative dependence on temperature in the range of 198-648 K. The rate constants for Cl atoms of methyl acrylate (MA), EA, methyl methacrylate (MMA), and allyl acetate (AAC) are k > k > k > k . The atmospheric lifetime of EA is 154.3 h for Cl-initiated oxidation which is compared with that of the reaction of other oxidants (OH radicals, O molecules, and NO radicals) with EA. [ABSTRACT FROM AUTHOR]

Background: The production and consumption of greenhouse gases (GHGs) in soils are largely regulated by biological processes. Increasing atmospheric CO may alter these processes, thereby affecting GHG emissions and their feedbacks to climate. Methods and aims: Here, we used an open top chamber (OTC) experiment to examine the effects of elevated CO for ten years on soil GHG fluxes in a Quercus mongolica dominated system in northeastern China. Results: Our results showed that elevated CO increased soil CO emissions, consistent with increased microbial biomass and the abundance of arbuscular mycorrhizal fungi and actinomycetes. Additionally, elevated CO increased CH uptake due to stimulated growth of methanotrophs. The seasonal mean soil NO flux was not changed by elevated CO, consistent with unchanged ammonia oxidizing bacteria, archaea and denitrifiers, which was probably due to large variations between the individual OTCs and with time. However, seasonal cumulative soil NO emissions increased by 64.7% under elevated CO. Our results also hinted that nitrification by ammonia oxidizing archaea was the major process of soil NO emissions. Conclusions: In our study elevated CO increased soil GHG emissions and the cumulative global warming potential by 27.8%, causing an important positive feedback to climate change. [ABSTRACT FROM AUTHOR]

The study is focused on the machined surfaced integrity of TB6 titanium alloy (Ti-10V-2Fe-3Al) after dry milling with carbide end mills of variable helix, variable pitch as well as conventional geometry. Roughness, residual stress, nanohardness, and microstructure alterations are investigated. The results show that not only the cutting speed and feed but also the geometric structure parameters of milling cutters have influence on the surface roughness and residual stress. Nanohardnesses exhibited inconsistent variation from the machined surface to bulk material. Plastic deformations and defects are detected in the machined surface. The deformation twins impact the anisotropy, the hardening effect, and the plasticity of TB6 titanium alloy machined surface. [ABSTRACT FROM AUTHOR]

Process and rate of the crater wear development on the rake face of uncoated cemented carbide inserts were investigated when Ti-6Al-4V alloy was turned under dry cutting conditions. Contour maps were outlined to study the relationship between the area of the contour region and its wear depth. An effectively predictive method was proposed to predict wear-related quantities of the crater, including the crater depth, wear area, and wear volume. The predictive method was verified by the experiments with different cutting parameters. The development rate of the crater with the wear depth was acquired by analyzing the relationship between the area of the contour boundary region and its wear depth, and reasons on a sharp increase of the development rate were discussed at the wear depth of ( KT-1) or ( KT-2). The relationship between the area of the contour region and cutting time at a certain wear depth was proposed and could be used to predict the wear-related quantities of the crater. [ABSTRACT FROM AUTHOR]

This paper presents a simple spatial phase shift shearography based on the Michelson interferometer. A novel digital shearography set-up with a large angle of view, which is based on a 4 f system is demonstrated. In the system, the Michelson interferometer is used as a shearing device to generate a shearing distance by tilting a small angle in one of the two mirrors. In fact spherical wave fronts become plane after going through the first lens in 4 f system. Tilting the mirror in the Michelson interferometer also generates spatial carrier frequency. Sinusoid fitting method is applied to evaluate the phase. This system can generate a phase map of shearography by using only a single image. The effects of shearing angle, the choice of algorithm and comparison result are discussed in detail. The theory and the application are presented. [ABSTRACT FROM AUTHOR]

Titanium alloy TB6 is often used to produce key load carrying parts in the aviation and aerospace industries. The superior mechanical properties pose challenges to machining processes, bringing about such problems as rapid tool wear. In this paper, fine-grain WC/Co tools were utilized in dry turning of the TB6 alloy. The wear modes and wear mechanisms of the cutting tools at different cutting speeds were detailed. The analysis showed that the wear on the tool rake face was characterized as crater formation. The principal wear mode observed on the tool flank face appeared to be microchipping near the region of the cutting edge. The adhesion was more pronounced on the rake face than on the flank face. The clusters of WC particles were pulled out from the Co binder along the grain boundaries, which led to adhesive wear and left an intergranular fractured surface. The crater wear was a result of the elements of the cutting tool diffusing into the adhering material, which was carried away by the flowing chip, leading to a transgranular dissolution of the WC particles, and the worn surface was smooth. The chemical reaction possibly took place at the tool/adhering material interface, where the newly formed compounds were carried away by the flowing chip. The hard particles that adhered to the back surface of the titanium chip probably abrade the tool surface, causing abrasive wear. [ABSTRACT FROM AUTHOR]

Machining processes of Inconel 718 turbine disk including turning and broaching processes are, respectively, analyzed using the theorem of minimum potential energy. First, in order to provide the initial condition in terms of elastic strain energy for the machining processes, two-dimensional, axial symmetry assumptions are adopted and the simulation of multi-stage forging of disk is conducted and verified by the residual stresses test. Secondly, potential energy (PE) expression for the machining processes is developed. The predicted results of turning and broaching indicate that there exists an optimal value of removed material, and high level of strain energy signifies an unstable state of the structure, which could make the part deform to keep self-equilibrium. [ABSTRACT FROM AUTHOR]

The Al–50Si alloy, as a kind of potential electronic packaging material, is manufactured by different methods, such as casting and spray deposition. The possible influences of the P refiner on the microstructure of the Al–50Si alloy are investigated at different cooling rates. The refinement mechanism of primary Si phase is discussed in view of the P refiner addition, and the variation of the cooling rates. The thermal conductivity (TC), as a key parameter for electronic materials, is measured. The coupled effects of the cooling rate and the addition of the P refiner during the solidification of the Al–50Si alloy on the TC are elucidated based on structural observations. Furthermore, the porosity in the Al–50Si alloy is treated as a second phase influencing the TC. [ABSTRACT FROM AUTHOR]

This paper examines the effect of corporate social responsibility (CSR) on the number of bond covenants. We find that a high CSR score has a negative association with the number of bond covenants. Moreover, our results are more pronounced for firms with a high bid-ask spread and high agency costs. Our analysis highlights the effect of the good stakeholder relationship on the bond contracts. [ABSTRACT FROM AUTHOR]

Based on sharp geometry of Ni nanowires, we developed a novel high-gradient magnetic separator that was composed of a nanowires array and a uniform magnetic field. When suspension of magnetic nanoparticles (MNPs) flowed through it, the relatively large nanoparticles or clusters were removed from the suspension so that the size distribution can be improved. The separation resulted from magnetic force so that extra molecules or solvents were unnecessary to add. The performance was proved by scanned electron microscopy characterization and dynamic light scattering measurement. The improvement in magnetic colloidal dispersivity is important for the biomedical application of MNPs. Our results may also play a role in microfluidic application and nanoparticle-based detection. [ABSTRACT FROM AUTHOR]

Nickel based super-alloys are widely employed in aircraft engines and gas turbines due to their high temperature strength, corrosion resistance and, excellent thermal fatigue properties. Conversely, these alloys are very difficult to machine and cause rapid wear of the cutting tool, frequent tool changes are thus required resulting in low economy of the machining process. This study provides a detailed review of the tool wear mechanism in the machining of nickel based super-alloys. Typical tool wear mechanisms found by different researchers are analyzed in order to find out the most prevalent wear mechanism affecting the tool life. The review of existing works has revealed interesting findings about the tool wear mechanisms in the machining of these alloys. Adhesion wear is found to be the main phenomenon leading to the cutting tool wear in this study. [ABSTRACT FROM AUTHOR]

We present the behavior of the thermoelectric response in a nanoscale tungsten-constantan (Cu 58%, Ni 42%) thermocouple (TC). The TC is tip-section typed and fabricated by the stepping method. The thermal electromotive force (emf) showed nearly linear behavior versus temperature over the range from 0 to 100C. For the thermocouples with contact radius below 300 nm, the Seebeck coefficient decreased with the size of thermocouples turning smaller. According to the theory based on the free-electron model, the size-dependence thermal electric response may be ascribed to the change of electronic property in nanoscale. [ABSTRACT FROM AUTHOR]

In order to improve the giant magneto impedance (GMI) of Co-rich wires for high sensitive sensor applications, CoFeSiB wires were prepared by melt an extraction technique and subjected to Joule stress-current anneal treatments with different tensile stresses applied. And then their GMI response was investigated at a frequency range from 0.1 to 13 MHz. It was found through the comparison of results that the GMI effect of these wires had been improved through stress-current anneal treatments, because the tensile stress applied on these Co-rich wires introduced magnetoelastic energy and increased anisotropy, which improved the circular permeability and GMI effect. Their impedance ratio Δ Z/ Z increased from 244% to 480.9% at 7 MHz and the field sensitivity increased to 0.83%/(A/m) at 5 MHz, when a tensile stress of 244 MPa was applied at an anneal current of 100 mA for 10 min. It was therefore concluded that these annealed wires were suitable for high sensitive sensor applications. [ABSTRACT FROM AUTHOR]

morphous CoFeSiB wires with smooth surface and circular cross section were fabricated by melt extraction technology using a copper wheel with a knife-edge cross section angle of 60 deg. The effect of some process parameters such as wheel circumference velocity, molten alloy feed rate, and temperature on the geometry and weight, i.e., melt extracted layer thickness, of wire was examined carefully. An optimum process parameter to produce high-quality circular wires was presented. A high resolution CCD video camera recorder was used to monitor the changing of the surface shape of molten alloy contacting the wheel tip under different conditions. It was found that the mechanism of the wire formation during the optimum process condition was controlled by the momentum mechanism, while in the low wheel speed region, heat transfer turned out to be a dominant factor. Some characteristics of the circular wires such as amorphous nature and tensile strength were also studied. [ABSTRACT FROM AUTHOR]

1-D crystallization process has been analyzed for thermal diffusion by solving the Fourier equation. The expressions of thermal fields indicate that the temperature decreases as the crystal grows and the temperature decreases in the solid phase as the crystal growth rate decreases. The trend of temperature variation is the opposite in the liquid phase. Meanwhile the temperature gradient decays along the crystal growth direction in both the solid and liquid phases. An obvious temperature layer gradually appears as the crystal growth rate increases when the crystal grows in an undercooled melt. According to these results, the following guidelines are suggested for the quantitative process design of the 1-D crystallization at a constant crystal growth rate: (1) the heater temperature must be decreased as the crystal grows along a route established using a formula, (2) the linear simplification of temperature distribution is applicable to the process design of crystallization only below a high growth rate limit, and (3) in order to keep the crystal growing in a non-undercooled melt, its growth rate cannot exceed a maximum. [ABSTRACT FROM AUTHOR]

Ti42.5Zr7.5Cu40Ni5Sn5 bulk metallic glass with a critical diameter of 4 mm was fabricated by the conventional copper mould casting method. The supercooled liquid region Δ T x, reduced glass transition temperature T rg, γ parameter, and δ parameter of the alloy were measured to be 63.9 K, 0.561, 0.393, and 1.400, respectively, implying that the alloy has an excellent glass-forming ability. The bulk metallic glass exhibits high compressive fracture strength of 2162 MPa with distinct plastic strain of 0.9%. The fracture surface consists mainly of vein-like patterns, typical of bulk glassy alloys. [ABSTRACT FROM AUTHOR]