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Directionally solidified porous copper is considered as a potential candidate in the field of microchannel heat sinks. By the Bridgman-type directional solidification method, a porous copper ingot was fabricated. Evolution of the porosity, pore number density, average pore diameter and average interpore spacing at different ingot heights was investigated. The results show that with the increase of ingot height, the porosity firstly increases and then basically remains unchanged from the ignot height of 65 mm; the pore number density rapidly decreases at first, and the decreasing speed becomes slower when the ignot height higher than 85 mm; the average pore diameter increases and then remains unchanged from the ingot height of 85 mm; the average interpore spacing increases, and the increasing speed of average interpore spacing becomes slower with the increase of height to higher than 85 mm. In order to study the evolution of diameter and spatial distribution of pores, the distribution ranges of pore diameter, nearest-neighbor distance and radial cumulative pore number were analyzed. As the ingot height increases, the distribution ranges of pore diameter and nearest-neighbor distance firstly increase and then tend to be stable. There are no pore clusters and for long distance, the spatial distribution of pores is uniform at different ingot heights. Pore structure and 3D pore morphology of porous copper were observed with the help of light illumination and X-ray tomography. Pore nucleation, pore interruption, pore coalescence, diameter change of pores and lateral displacement of pores were found to exist in the pore structure. [ABSTRACT FROM AUTHOR]

The title compound, [Co(C11H16N3O)(H2O)]Cl, consists of a [Co L]+ cation and a chloride anion, where L is the N-(2-oxidophenyl­methyl­imino)-3-aza­pentane-1,5-diamine anion. In the complex cation, the Co atom is coordinated by three N and two O atoms from the ligand and an apical water mol­ecule in a distorted square-pyramidal geometry. The crystal structure is stabilized by N—H⋯O, N—H⋯Cl, O—H⋯O and O—H⋯Cl hydrogen bonds. [ABSTRACT FROM AUTHOR]

In order to improve the performance of plaster molds for investment casting, a diverse content of glass fiber and polypropylene (PP) fiber was incorporated into the slurry for the preparation of a fiber-reinforced mold. The green and fired bending strengths, thermal expansion properties, permeability, and thermal shock resistance of the mold were examined, and the scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) was applied for the observation of fracture morphology. With appropriate content, the introduction of glass fiber was proved to increase the green bending strength and fired bending strength, restrain the thermal expansion and improve the thermal shock resistance of the mold, while the polypropylene fiber added was able to raise the green bending strength and the permeability, reduce the thermal expansion and heighten the thermal shock resistance as well, though the fired bending strength would be weakened slightly. Evenly distributed fibers were capable of enhancing the mechanical properties of the matrix, but agglomerations and bundles of fibers resulting from excessive addition had a negative impact. Meanwhile, it was also manifested that micropores left by ablative polypropylene fibers could improve the permeability and reduce the thermal expansion of the mold, and the fired bending strength would be decreased slightly by the deterioration of continuous structure. Three different ratios of hybrid fiber were employed in plaster molds, which can meet altered requirement of castings. The samples modified with hybrid fiber possessed lower thermal deformation, higher air permeability, and better resistance of thermal shock, while the mechanical strength was equal to the fiber free sample or slightly increased. [ABSTRACT FROM AUTHOR]

Fe83Ga17 alloy is a kind of promising magnetostrictive alloys with high magnetostrictive properties and a low saturation magnetic field. As-cast Fe83Ga17Dyx (x=0, 0.05, 0.1, 0.2, 0.4) polycrystalline alloys were prepared by arc melting. Effect of Dy doping on the microstructure, magnetostrictive and mechanical properties of as-cast Fe83Ga17 alloy was investigated. Results show that Dy-doped alloys exhibit a dual-phase structure containing the A2 matrix and Dy-rich precipitates (Fe56Ga34Dy10). Both magnetostriction and mechanical properties of Fe83Ga17 alloys are improved by Dy doping. A small amount of Dy addition (x=0.2) significantly causes Fe83Ga17 alloy to transform from typical brittle material (fracture strain e<1%) to plastic material (e-11%). Correspondingly, the fracture mode transforms from intergranular fracture to dimple fracture. At the same time, the ultimate tensile strength and the magnetostriction rise up to 209 MPa and 64 ppm, respectively. Dy-rich precipitates disperse along the grain boundries and inside the grains, which plays an important role in the grain refinement and solution strengthening, and therefore, contribute to the enhancement of mechanical properties of the alloy. The improvement of magnetostriction could be attributed to the large lattice distortion induced by Dy atoms entering into the A2 matrix. Doping Dy into Fe-Ga alloys provides an effective solution to the brittleness in their applications. [ABSTRACT FROM AUTHOR]

Magnesium aluminate (MgAl2O4) platelets were first synthesized by hydrothermal treatment of γ-AlO(OH) in a magnesium nitrate aqueous solution at 400°C. The platelets are 100–200 nm in width and 25 nm in thickness. The influence of temperature, the anions of the magnesium salt, the amount of magnesium salt, and precursor pH on the formation of such structure was investigated. The experimental results indicated that the anions of the magnesium salt and precursor pH could have a significant influence on the growth of MgAl2O4. MgAl2O4 formation followed the in situ transformation mechanism, which was the reason why the MgAl2O4 crystallites had a platelet morphology. [ABSTRACT FROM AUTHOR]

This paper summarizes melting methods of titanium and titanium alloy, such as vacuum arc melting (VAR) and electron beam cold hearth melting (EBCHM), and the related inclusions formed when using these melting methods. Low-density inclusions are resulted from contamination of air, and high-density inclusions are caused by refractory elements. The formation process of inclusions was analysed. The removal mechanism of different kinds of inclusions was specified. Low-density inclusions are removed mainly by resolving. This is a comprehensive process containing reaction diffusion. The resolving rate of high-density inclusions is so low that these inclusions are mainly removed by sedimentation. The experiments and physical models of inclusions are detailed. In various melting methods, vacuum arc melting is prominent. However, this method cannot remove inclusions effectively, which usually results in repeat melting. Electron beam cold hearth melting has the best ability of removing inclusions. These results can provide instructions to researchers of titanium and titanium alloys. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the anti-fatigue activity of maca hydroalcoholic extract (ME), which mainly contains macamides and polysaccharides. ME was prepared by circumfluence extraction with enzymatic pre-treatment. Antifatigue activity of ME was investigated in weight-loaded forced swimming mice, with pure macamides and commercially available maca tablet as positive control. Compared with normal group, pure macamides treatment group could prolong the swimming time to exhaustion, but there was no statistically significant difference (P > 0.05); while ME (middle-dose and high-dose groups) could effectively prolong the swimming durations (P < 0.05). Supplementation with pure macamides significantly decreased blood lactic acid (BLA), whereas ME significantly increased hepatic glycogen (HG), decreased BLA, and blood urea nitrogen (BUN) compared with those in normal control (P < 0.05). The results suggested that the anti-fatigue effect of ME was better than that of pure macamides, which can be explained by the increase of glycogen storage and the reduction of metabolites accumulation. [ABSTRACT FROM AUTHOR]

The influence of Si, Sn, Mo and Ni on the ductility and thermal conductivity of compacted graphite iron (CGI) was investigated. Metallographic observation and Differential Scanning Calorimetry (DSC) experiments were carried out to analyze the roles of various additions in the eutectoid reaction. The experimental results showed that the ductility of CGI is proportional to the ferrite fraction, so moderate Si content could dramatically improve the ductility by increasing the ferrite fraction. DSC measurements showed that Mo has moderate inhibition on eutectoid transformation during both the heating and cooling processes, while the sample without Sn obviously broadens the three-phase region. Vermicularity and ferrite are known to improve thermal conductivity, and the former plays a more important role. Besides, among the alloy elements investigated, Sn has the greatest negative effect on conductivity, followed by Ni and Mo having the smallest effects. [ABSTRACT FROM AUTHOR]

Magnetic mechanisms for the (Co,Al)-codoped ZnO, based on the first-principles calculations, are evaluated. Additional electrons induced by Al doping can stabilize the ferromagnetic state in Co-doped ZnO. The Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction may be the dominant mechanism when the distance between Co and Al is far away, while the double-exchange interaction may gain an advantage over the RKKY when the distance is near. The multiple mechanisms can explain the relationship between the magnetic performance and the relative substitutional site of Al. The study yields insight into the origin of the ferromagnetism of ZnO-based materials. [ABSTRACT FROM AUTHOR]

This paper reports that the Zn0.95Co0.05O polycrystalline powder and thin film were prepared by sol-gel technique under the similar preparation conditions. The former does not show typical ferromagnetic behaviour, while the latter exhibits obvious ferromagnetic properties at 5 K and room temperature. The UV–vis spectra and x-ray absorption spectra show that Co2+ ions are homogeneously incorporated into ZnO lattice without forming secondary phases. The distinct difference between film and powder sample is the c-axis (002) preferential orientation indicated by the x-ray diffraction pattern and field emission scanning electron microscopy measurement, which may be the reason why Zn0.95Co0.05O film shows ferromagnetic behaviour. [ABSTRACT FROM AUTHOR]