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Abstract: Resonant Raman scattering of second-order Raman modes from an individual graphite whisker synthesized by a high-temperature heat-treatment method at a special pressure was discussed here. The dependence of phonon frequencies on the incoming laser light and the frequency difference between Stokes and anti-Stokes scattering show their origin from double resonance Raman scattering. Our results show that all the experimental results of second-order Raman modes in graphite whiskers, such as the excitation-energy dependence on the mode frequency, the frequency shift between a second-order Raman mode and its fundamentals, and the frequency discrepancy between Stokes and anti-Stokes components of a second-order Raman mode can be well understood by double resonance Raman scattering. [Copyright &y& Elsevier]

Abstract: The barrier effect of Pt and Ni has been investigated in the Ti/Al/Pt/Au and Ti/Al/Ni/Au Ohmic contacts to n-GaN, respectively. Severe indiffusion of Pt and Au has been found in the 800°C annealed Au/Pt/Al/Ti/n-GaN samples. However, Ni does not penetrate into the n-GaN and shows better barrier effect for preventing Au penetration into Au/Ni/Al/Ti/n-GaN samples. The reaction between Ga and Pt has also been identified in the samples annealed at 600°C. At the same time, the electrical degradation was found for the Ti/Al/Pt/Au samples aged at 600°C. However, no obvious degradation was found for the aged Ti/Al/Ni/Au samples. It is suggested that the reaction between Ga and Pt may cause the electrical degradation of the Ti/Al/Pt/Au metallization system. [Copyright &y& Elsevier]

Abstract: The vertical conductivity of the p-Al0.11Ga0.89N/GaN SLs has been measured and calculated. The measured result (1.35×10−5 Scm−1) is in good agreement with the calculated result (2.26×10−5 Scm−1), indicating that the adoption of Fermi–Dirac distribution and sequential tunneling model in our calculation is very plausible. As a result, it is suggested that in p-AlGaN/GaN SLs the Fermi–Dirac distribution need to be considered in calculation related to hole distribution. [Copyright &y& Elsevier]

Abstract: The temperature dependent diffusion and epitaxial behavior of oxidized Au/Ni/p-GaN ohmic contact were studied with Rutherford backscattering spectroscopy/channeling (RBS/C) and synchrotron X-ray diffraction (XRD). It is found that the Au diffuses to the surface of p-GaN to form an epitaxial structure on p-GaN after annealing at 450°C. At the same time, the O diffuses to the metal–semiconductor interface and forms NiO. Both of them are suggested to be responsible for the sharp decrease in the specific contact resistance (ρ c) at 450°C. At 500°C, the epitaxial structure of Au develops further and the O also diffuses deeper into the interface. As a result, the ρ c reaches the lowest value at this temperature. However, when annealing temperature reaches 600°C, part or all of the interfacial NiO is detached from the p-GaN and diffuses out, which cause the ρ c to increase greatly. [Copyright &y& Elsevier]

Abstract: The influence of various annealing temperatures on microstructure evolution of oxidized Ni(20nm)/Au(20nm) ohmic contact to p-GaN was studied by synchrotron X-ray diffraction (XRD). In association with the variation of the specific contact resistance (ρ c), it is observed that NiO and Au began to form partially epitaxial structure on p-GaN at 450°C, which played a critical role in lowering down the ρ c. At 500°C, the epitaxial structure of Au and NiO was improved further while the lowest ρ c was reached. However, at 600°C, the epitaxial structure of NiO was transformed to polycrystalline structure again with a sharp increase of ρ c. Therefore, it is suggested that the degradation of the epitaxial structure of NiO is responsible for the sharp increase of ρ c. [Copyright &y& Elsevier]

Abstracts: The microstructure evolution of oxidized Ni (20nm)/Au (20nm) contact to p-GaN with increasing annealing temperature was studied by synchrotron X-ray diffraction (XRD) and powder XRD. With the increase of annealing temperature, it was observed that the Au on the p-GaN gradually grew on the p-GaN with the orientation relationship of Au(111)//GaN(0002). NiO also had such a orientation relationship of NiO(111)//GaN(0002) at 500°C and gradually turned back to polycrystalline structure at higher temperature. The orientation relationship of Au, NiO and GaN implied that the epitaxial crystallization might occur during annealing. The specific contact resistance also reduced to the minimum 2.73×10−4 Ωcm2 at 500°C. Therefore, plausibly the epitaxial crystallization is an important mechanism for lowering the contact resistance between oxidized Ni/Au contacts and p-GaN. [Copyright &y& Elsevier]

Abstract: The effect of surfactants on the treatment of chemical mechanical polishing (CMP) wastewater by electro-coagulation-flotation (ECF) process was studied. Two surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) were employed in this study to compare the effect of cationic (CTAB) and anodic (SDS) surfactants on ECF. The cationic surfactant can enhance the removal of the turbidity, but anodic surfactant cannot. It can be explained by the hetero-coagulation theory. Moreover, the addition of CTAB in CMP wastewater can reduce the sludge volume and the flotation/sedimentation time in ECF process. The residual turbidity and dissolved silicon dropped with the increase of charge loading. No CTAB pollution problem exists after the ECF process. [Copyright &y& Elsevier]

Abstract: The effect of the molar ratio of hydroxide and fluoride ions to Al(III) ions ( and ) on coagulation and electrocoagulation (EC) was studied to solve the problem of the over addition of acid or base. The efficiency of defluoridation was approximately 100% when the sum of and () was close to 3. This finding reveals that the fluoride ions and the hydroxide ions can co-precipitate with Al(III) ions and the formula of the precipitate is AlnFm(OH)3n-m. However, when was less than 2.4, the defluoridation efficiency, given that , dropped as fell, because the amount of aluminum polymer formed dropped. The efficiency of defluoridation of EC exceeded that of coagulation for equal and , when , proving the existence of an electrocondensation effect. [Copyright &y& Elsevier]

Abstract: This work employs an anodic surfactant, sodium dodecyl sulfate (SDS), to improve the flotation performance of the electrocoagulation–flotation (ECF) process to treated fluoride containing semiconductor wastewater following calcium precipitation. The dissolved fluoride ions and CaF2 particles in the wastewater after calcium precipitation were effectively removed in the ECF process simultaneously. The dosage of SDS required for ECF was much less than those for dispersed air flotation (DiAF) or dissolved air flotation (DAF) processes because the CaF2 particles can be collected by hydro–fluoro–aluminum flocs in ECF. Thus, SDS only served as a frother to make the bubbles tiny and stable in the ECF defluoridation process. The interference of co-existing anions can be overcome by increasing the dosage of calcium ions and SDS. The optimum initial acidity for ECF is close to the initial fluoride concentration after calcium precipitation; the amount of SS removed dropped rapidly if the initial acidity exceeded the optimal value because the surface charge of the hydro–fluoro–aluminum particles increased. The initial acidity of the wastewater after calcium precipitation can be modified by changing the [Ca(OH)2]/[Ca2+]T ratio and the appropriate ratio is approximately given by the acid dissociation constant of hydrofluoric acid and the initial pH of the wastewater before calcium precipitation. [Copyright &y& Elsevier]

Batch experiments with bipolar aluminum electrodes and potentiodynamic polarization tests with monopolar systems were conducted to investigate the effects of the type and concentration of co-existing anions on defluoridation in electrocoagulation (EC) process. The results demonstrate that the type of the dominant anion directs the EC defluoridation reaction. The defluoridation efficiency was almost 100% and most of the fluoride removal reaction occurred on the surface of the anode in the solution without the co-existing anions, due to the electro-condensation effect. In the solutions with co-existing anions, most of the defluoridation took place in bulk solution. The residual fluoride concentration is a function of the total mass of Al(III) liberation from anodes and the types of the functions in the solutions with and without co-existing anions are different. The existence of sulfate ions inhibits the localized corrosion of aluminum electrodes, leading to lower defluoridation efficiency because of lower current efficiency. The presence of chloride or nitrate ions prevented the inhibition of sulfate ions, and the chloride ions were more efficient. Different corrosion types occurred in different anion-containing solutions and the form of corrosion affected the kinetic over-potential. The bypass flow causes the decrease of current efficiency and the proportion of the bypass flow of current increased due to a rise of the kinetic over potential and the conductivity of the solution. [Copyright &y& Elsevier]

Ni-free and Ni-bearing steels were designed to elucidate the effect of Ni on the free energy of bainitic transformation. Steels with two distinct nano-bainite structures were obtained through conventional one-stage and two-stage isothermal treatments. The effect of work hardening and accompanying strain on martensitic transformation of the two nano-bainite structures was also studied. Microstructure of both the steels consisted of bainitic ferrite and film-like and block-like retained austenite (RA). The total carbon concentration, degree of Fe–C cluster formation, and stability of RA were significantly affected by the free energy of bainitic transformation. The presence of Ni leads to reduction in the free energy of bainitic transformation, refinement of bainite structure, and extension of bainite nucleation regime. The carbon-content in block-like and film-like RA microstructure of Ni-bearing steel was 5.5% and 19.1%, respectively, which was greater than Ni-free steel. The load-displacement behavior indicated superior strain hardenability and higher strain hardening rate (SHR) in Ni-bearing steel. The uniform nanostructure of Ni-bearing steel promoted the formation of stable film-like RA between bainitic ferrite, leading to higher strain hardening rate and stronger transformation-induced plasticity (TRIP) effect at large strain. The Ni-bearing steel was characterized by superior plasticity (13.7%–10.3%) and product of tensile strength and % elongation (25.9 GPa·% to 20.9 GPa·%) in comparision to the Ni-free steel. [ABSTRACT FROM AUTHOR]

Studies the effect of retinoic acid on the differentiation of cultured porcine preadipocytes. Effect of pharmacological concentrations of retinoic acid on glycerol-3-phosphate dehydrogenase activity of pig preadipocytes; Effect of retinoic acid on morphology; Effect of retinoic acid administration at different time intervals.

Abstract: The annealing time-dependent diffusion behavior of oxidized Au/Ni/p-GaN ohmic contact was studied with Rutherford backscattering spectroscopy/Channeling (RBS/C). It was found that, at 500°C, 1min annealing caused obvious indiffusion of Au, O and outdiffusion of Ni. And the Au even has diffused to the p-GaN/metal interface. According to the annealing time-dependent RBS spectra and referring to the correspondent specific contact resistance of the samples, it is suggested that indiffusion of Au and formation of NiO at the interface are among the critical mechanisms for the formation of low resistance ohmic contact with Au/Ni/p-GaN contact structure. [Copyright &y& Elsevier]

Abstract: Influences of laser lift-off (LLO) process on the performances of large-area light emitting diodes(LALEDs) have been investigated. The current–voltage (I–V), light output power–current (L–I) and electroluminescence (EL) results are presented for the same LALEDs before and after LLO process, respectively. In this way, it was proved that the LLO process had no influence on the I–V profiles and the wavelength of the LALEDs. However, the detachment of the sapphire substrate increased the light output of the LLO-LALEDs. [Copyright &y& Elsevier]

The concept of phase reversion annealing involving cold deformation of metastable austenite to strain-induced martensite, followed by annealing was adopted to obtain fine grained 18Cr–8Ni austenitic stainless steel. The primary objective of the present study was to elucidate the wear performance of fine-grained austenitic stainless steel through three-body abrasive wear tests at room and high temperatures and compare with the coarse-grained counterpart. The quartzite stones (quartz content over 90 wt%) with diameter 5–15 mm and hardness of 1100HV were used as the abrasive in three-body abrasive wear tests. The study demonstrated that the microstructure consisting of near defect-free and equiaxed fine austenite grains with high yield strength and elongation exhibited superior wear resistance at high temperature (250 °C), which is attributed twinning induced plasticity deformation in fine austenite grains. The wear mechanism varied as a function of distance from the center of the steel sample and was characterized by microploughing and microcutting. • Fine-grained austenitic stainless steel exhibited superior wear performance in the three-body abrasive wear test at 250 °C. • Microploughing was the main wear mechanism at the edge part of sample in the three-body abrasive wear tests, whereas microcutting was key wear mechanism in the center part. • The shift in wear mechanism resulted from the external force. [ABSTRACT FROM AUTHOR]

A commercial scale Mg-7Gd-2Y–1Zn-0.5Zr alloy extrusion rod with synergetic high yield strength of 350 MPa and fracture toughness K IC of 22.4 MPa m1/2 was fabricated by direct-chill casting, hot extrusion and subsequent aging treatment at 200 °C for 108 h. The microstructures and mechanical properties of the as-extruded and peak-aged alloys were investigated, and the fracture toughness and fracture mechanisms before and after aging treatment were also analyzed. The results showed that the as-extruded alloy consisted of long period stacking ordered (LPSO) phase and bimodal matrix microstructure composed of fine dynamic recrystallized (DRXed) grains and coarse deformed grains. Microstructural analysis near fracture surfaces indicted that twinning was activated in the coarse deformed grains during fracture toughness test, which may be conducive to the improvement of the fracture toughness of the alloys. The lamellar-shaped LPSO phases enhanced the fracture toughness since the formation of secondary cracks parallel to the lamellar LPSO can cause significant energy dissipation and deflection of main crack. The micro-cracks were initiated and propagated in the bulk LPSO phases, which may deteriorate the fracture toughness. Large amount of nano β' phase precipitated in the T5 peak-aged alloy significantly improved the strength of the alloy. Fractography analysis indicated that fracture mechanism changed from ductile fracture of the as-extruded alloy to quasi-cleavage fracture of the peak-aged alloy. The precipitation of β' would suppress twin growth and induce the microcracks initiated at the DRXed grain boundaries and in the deformed grains, which led to slight decrease of K IC. [ABSTRACT FROM AUTHOR]

Abstract: Particulate barium fluxes on the continental shelf of Prydz Bay in east Antarctica were measured by using time series sediment trap deployed at two stations with trap depth about 500m during 7/12/2009–15/2/2010 and 16/12/2010–16/12/2011. The annual fluxes were 12.3mgm−2 yr−1 and 18.4mgm−2 yr−1 for barium, and 8.9mgm−2 yr−1 and 14.9mgm−2 yr−1 for biogenic barium at two stations, respectively. More than 72% of the barium is from biogenic source. The temporal–spatial variations of biogenic barium fluxes and the ratio of biogenic barium to organic carbon are related to the variation of organic matter export in the upper water column. Biogenic barium flux and organic matter export are generally positive correlated. However, biogenic barium precipitation is less efficient under conditions of high organic matter exports during times of greater primary productivity, which leads to relatively less cycling of organic carbon and in turn produces less barite formation based on the hypothesis that barite forms through organic matter decomposing in microenvironment. More than 72% of the rained biogenic barium at the trap depth was preserved in the sediment. High preservation efficiency of biogenic barium and good relationship between biogenic barium and organic carbon suggested that biogenic barium could be a reliable proxy for the marine export production. The calculated export productions are 6.9gCm−2 yr−1 and 14.9gCm−2 yr−1 at two stations respectively using the modified prediction equation, which is more suitable for predicating export production for margin and shelf systems. [Copyright &y& Elsevier]

Abstract: Anodic coatings were prepared by using microarc oxidation (MAO) on AZ91HP in silicate containing solution (Si-solution) and phytic acid containing solution (P-solution), respectively. The influence of the electrolytes on coating structure, morphology and composition was studied by using X-ray diffraction (XRD), environmental scanning electron microscope (ESEM) and energy dispersive X-ray spectroscopy (EDX). Potentiodynamic polarization test and immersion test were employed to evaluate the corrosion resistance of anodic coatings. Different electrolytes caused the differences in the MAO process and coating properties. The breakdown voltage and the final voltage in P-solution were higher than those in Si-solution. The pore uniformity of anodic coatings obtained in Si-solution (Si-film) was worse than that in P-solution (P-film). XRD analyses indicated that Si-film was amorphous, while P-film consisted of MgO. The corrosion resistance of the sample coated with P-film was better than that with Si-film. [Copyright &y& Elsevier]

Abstract: This paper deals three-dimensional axisymmetric quasi-static coupled thermoelastic problems for time-dependent boundary condition. The water vapor temperature and pressure relation assumed for the inner boundary. The water vapor temperature and pressure data were obtained from a thermodynamic steam table. Laplace transform and finite difference methods are used to analyze problems. The solution is obtained by using the matrix similarity transformation and inverse Laplace transform. We obtain solutions for the temperature and thermal deformation distributions in a transient and steady state. Moreover, the computational procedures established in this thesis, can solve the generalized thermoelasticity problem for multilayered hollow cylinder with nonhomogeneous materials. [Copyright &y& Elsevier]

The thermal annealing effects on Ti/Al/Ni/Au Ohmic contact to n-GaN are investigated by current–voltage (I–V) characteristics and transmission line method (TLM) measurements. The cladding layer of Ni/Au on Ti/Al plays two roles: preventing inter-diffusion of Ti, Al, Au and anti-oxidation of the contacting layer. The specific contact resistance (ρc) of Ti/Al/Ni/Au to n-GaN increases slightly at first with the increasing annealing temperature (Ta). When Ta increases above 500 °C, ρc decreases monotonously in the range of 400–900 °C. However, the morphology of the contact degrades gradually when Ta increases above 600 °C. The minimum of ρc is obtained as 9.65×10-7 Ω cm2 by two-step annealing method in this work. Finally, the roles of two-step annealing method in the formation mechanism of the Ohmic contact to n-GaN are also discussed. [Copyright &y& Elsevier]

Abstract: The n-type GaN layers of high power blue light-emitting diodes (LEDs) were roughened successfully and formed a “cone-like” surface by photo-enhanced chemical (PEC) etching method. As a result, the extraction efficiency of the surface roughened LED increased. A simple model has been constructed to explain the relationship between the hexagonal cones and the extraction efficiency of roughened surface. A promising effect as high as 2.5 folds of surface roughing was predicted by the model. [Copyright &y& Elsevier]

Concerns surrounding climate change and environmental challenge make the coal utilization network essential not only for understanding the pattern of energy provision and transfer, but also for illustrating the interaction between anthropogenic activities and ecological systems at global level. This paper fills the research gap by dint of multi-regional input output model to outline coal embodied routes from natural boundaries to economic activities, and to identify the central hubs in the global coal supply chain, based on the most recent available statistics for 2011. As the economic value and environmental influences of different kinds of coals could be remarkably diverse, the separation of coal categories in systematic analysis could provide fundamental information regarding the displacement and teleconnection of coal utilization in the world. The estimation shows that in weight 64.99% of coal direct supply is ultimately embodied in international trade, indicating the crucial roles of trade interlinks in global coal utilization. Apart from this, the findings pertinent to sectoral structure, regional supply chain and per capita characteristics of coal embodied utilization, could be valuable to identify the global energy routes driven by international trade as well as to facilitate energy and environmental policy. [ABSTRACT FROM AUTHOR]

• The fatigue life prediction model based on the surface integrity features was developed. • The eigenstrain method was used to restructure the residual stress field after milling. • Simulation of different feed rates impact on fatigue life after milling. • Mapping from microscopic characteristics to macroscopic mechanical properties was established. The surface integrity of AISI 4140 steel after milling at different feed rates (75–125 mm/min) was measured by performing laser scanning microscopy, X-ray diffraction, and electron backscatter diffraction. Subsequently, the fatigue responses under different maximum stress values (650–800 MPa) were analyzed. The results showed that the increase in the feed rate increases the residual stress and roughness, whereas the fatigue life at low stress is reduced. Moreover, the feed rate has a limited effect on the surface grain refinement layer, and fatigue life at high stress. The measured surface integrity models were used to predict the fatigue life based on the crystal plasticity theory, and these yielded results within the three times scatter bands from the corresponding experimental values. [ABSTRACT FROM AUTHOR]

This study assessed the oral health disparities and oral health care needs of children whose parents are Southeast Asian immigrant women in arranged transnational marriages. We used the baseline data of the Lay Health Advisor Approach to Promote Oral Health Program (LHA-POHP) to explore the disparities in oral health between immigrant and native children, and the factors associated with their oral health. A cross-sectional community-based study was conducted to collect data from mothers and their preschool children in Southern Taiwan in 2011. A total of 590 (440 natives, 150 immigrants) children aged 4-6 years and their mothers completed the questionnaire and oral examination. Multiple regression models were used to analyze the association between children's oral health and their related factors. The caries index was 6.05 in immigrant children and 3.88 in native children (p < 0.001). The caries prevalence of maxillary anterior teeth in the labial surfaces was higher among immigrants, ranging from 14.7 to 22%. The factor associated with children's caries index was maternal tooth brushing frequency (adjusted odds ratio [aOR] = 8.95, 95% confidence interval [CI] 1.95-41.05). When the mothers did not direct children to brush teeth after eating sweets, their children were more likely to have decayed teeth (aOR = 3.54, 95% CI 1.04-12.03). Children's filled teeth were related to their dental regular check-ups (aOR = 2.28, 95% CI 1.26-4.10). Disparities in oral health among immigrant and native children were observed. The findings suggest that culturally adequate oral health promotion intervention programs should be implemented for immigrants. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

• A low carbon footprint Ultra-High Performance Concrete (UHPC) is developed. • The idea of full scale recycling is proposed to reuse gold tailings. • The macro properties of the developed UHPC are evaluated. • The microstructure of the developed UHPC is presented. • The environmental characteristics of the developed UHPC are assessed. This paper presents a feasible way to design a low carbon footprint Ultra-High Performance Concrete (UHPC) with gold tailings based on the idea of full scale recycling. Due to the fact that the particle size distribution of the recycled gold tailings is normally wild, from micrometer to millimeter, it could be utilized to replace powders and aggregates in UHPC simultaneously, which can get rid of sieving process and improve the recycling efficiency. Therefore, in this study, a particle dense packing model is firstly employed to design the UHPC matrix with gold tailings, based on the full scale recycling point of view. Then, the fresh and hardened properties of the newly developed UHPC are investigated, including flowability, compressive strength, hydration kinetics, durability and microstructure. The tested results indicate that the idea of full scale recycling can guarantee a relatively high long-term compressive strength, low D RCM , and low leaching toxicity for UHPC. Additionally, the environmental evaluation further proves that the developed UHPC is a green building material with advanced properties and simple preparation process. [ABSTRACT FROM AUTHOR]

Electron spin dynamics in strained In0.1Ga0.9As/Al0.4Ga0.6As quantum wells (QWs) on (1 0 0) and (1 1 0)-oriented substrates are investigated by time-resolved Faraday rotation. We find that the spin relaxation time in (1 1 0) QWs is 6 times longer than that in (1 0 0) QWs at low temperatures, which is strongly reduced by applying magnetic fields. The sign of g-factor is found positive and its magnitude decreases with increasing well width, in the well width range investigated here. [Copyright &y& Elsevier]