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In the present paper, we develope a 3-D Msrf-integral to evaluate the surface energy that is corresponding to formation of multiple surface cracks. The Msrf-integral is formulated by modifying the conventional 3-D M-integral with deliberate origination of the coordinate system and proper delimitation of the integral surface. The integral is demonstrated to be surface-independent in a modified manner and so can be accurately evaluated provided an integration surface remote from the crack fronts is selected. With this feature, the theory of integration can be straightforwardly incorporated into the finite element method. In fact, it is not necessary to simulate the near-front regions with very fine FE simulations to obtain accurate solutions of Msrf.

In this study, the effect of wire selection (i.e., nickel, steel, copper and magnesium wires) on the feasibility of cold metal transfer plug welding of 3 mm thick Mg AZ31-to-1 mm thick galvanized mild steel was investigated. Welding tests with the use of various wires were conducted and the welded galvanized steel-Mg AZ31 joints were mechanically tested and analyzed with SEM, EDS, and micro-hardness analyses. The results indicated that among all wires tested in this study, sound Mg AZ31-galvanized steel joints with Mg AZ61 wire were obtained. Mg-Zn eutectic and thin Fe-Al intermetallic at the brazed interface between the weld metal and galvanized steel base metal were observed. A thin fusion zone between Mg AZ31 weld metal and base metal was formed, which led to the weld metal Mg AZ31 pulled out fracture mode. To summarize the tests conducted in this study, although good quasi-static tensile strengths were obtained for galvanized steel-Mg AZ31 joints made with NRNiCu-7 (Ni-based) wire, local cracks for galvanized steel-Mg AZ31 joints were often induced in the weld metals, which potentially would cause a concern in fatigue performance of the joints. Based on these results, it is recommended to use Mg AZ61 wire to join galvanized steel and Mg AZ31 by cold metal transfer plug welding.

The behaviors and effects of Zn-coating on the welding-brazing processes of steel with aluminum and magnesium were investigated by Cold Metal Transfer (CMT) arc. The behaviors of Zn-coating at the very beginning of burning and during the spreading of the liquid aluminum and liquid magnesium droplet over the steel plate were observed respectively. The effects of Zn-coating on the wetting process of liquid droplets and on the fracture of welding-brazing joints were analyzed. The effects of Zn-coating on joining mechanisms and tensile load of Al-steel joints and Mg-steel joint were compared and analyzed. For Al-steel, Mg-steel, some common behaviors can be found, the main effect of Zn is its evaporation which decreases the temperature at the interface to prevent steel from melting and makes the steel to expose the fresh metallic surface which is much easier to be spread by a liquid droplet than an oxidized surface. Zn-coating improves the wettability of liquid Al or liquid Mg over the steel surface. However, some effects of zinc coating on wetting behavior, joining mechanisms and tensile load of Al-steel joints and Mg-steel joint are still different. For Al-steel arc, Zn-rich triangle zone is not formed by driving the liquid Zn from inside and accumulated at the toe, rather it is formed by the diffusion of the liquid Zn from outside Zn-enriched periphery into the droplet. In the case of Mg-steel arc, the Zn-rich zone forms partly due to the accumulation of Zn driven from the center during the Zn evaporation. For Al-steel joint, Zinc coating has not reacted to form the interface layer between Al weld metal and steel, however, zinc coating reacted to form the interface layer between Mg weld metal and steel. Zinc coating improved the strength of Al-steel joints, but, it is not beneficial to the strength of Mg-steel joint.

Numerous studies have shown that osteoporosis is common in kidney transplant recipients. However, the change in bone mineral density after kidney transplantation (KT) is not fully understood.Thirty-nine kidney transplant recipients with bone densitometry at pretransplant and 24 months after KT were reviewed.The recipients' median age (44.5 ± 10.7 years) and dialysis duration before KT (4.2 ± 3.4 years) were recorded. The T-scores of the lumbar spine and femur neck at 24 months after KT were positively associated with the respective pretransplant T-score (P .001 in the lumbar spine and P .001 in the femur neck). However, the T-score after KT did not show significant change (P = .680 in lumbar spine, P = .093 in femur neck). Changes in the T-scores of the lumbar spine and femur neck over 24 months (delta T-score) were negatively associated with the respective pretransplant T-scores (P = .001 in lumbar spine, P = .026 in femur neck). Changes in the T-scores of the lumbar spine and femur neck over 24 months (delta T-score) were also associated with the pretransplant T-scores after the adjustment of other variables.The change of bone mineral density was related with pretransplant bone mineral density. Careful follow-up of bone densitometry for KT recipients was needed.

Arterial stiffness is associated with cardiovascular disease in end-stage renal disease (ESRD) and after kidney transplantation. We examined how kidney transplantation influences brachial-ankle pulse-wave velocity (baPWV) in ESRD patients.The prospective observational study enrolled 67 patients who underwent successful kidney transplantation. Serial baPWV and biochemical parameters were measured before surgery and 6 months, 1 year, and 2 years after transplantation.baPWV prior to kidney transplantation and 6 months, 1 year, and 2 years after transplantation was 1533 ± 261 cm/s, 1417 ± 254 cm/s, 1414 ± 285 cm/s, and 1384 ± 233 cm/s, respectively. baPWV and biochemical parameters including alkaline phosphatase, intact parathyroid hormone, and 1,25 hydroxyvitamin D improved significantly at 6 months (P .05), but there were no changes between 6 months and 2 years after transplantation. The majority of patients (73%) improved, whereas the remainder showed progression of baPWV after transplantation. Sixty-three percent of all kidney transplantation patients displayed higher baPWV than the healthy control subjects at 6 months after transplant.In the majority of patients, baPWV improved soon after kidney transplantation but overall remained higher than in the generally healthy population.

Besides the initial description of IgG4-related pancreatic disease, other sites are now commonly involved. However, occurrence of IgG4-related disease is rare in organ transplanted patients. A 57-year-old man who received a kidney transplantation presented with recurrent dyspnea on exertion. A computed tomography scan of the chest revealed bilateral interlobular septal thickening and multiple tubular and branching small nodular lesions in the right upper lobe, and mass-like consolidation of the left middle lobe. Despite no elevation of serum IgG4 level, a percutaneous core needle biopsy on consolidative mass showed interstitial fibrosis and infiltration of IgG4-positive plasma cells to be more than > 20 per high power field. After treatment with glucocorticoids and rituximab, the consolidative mass of the left middle lobe disappeared.

Spring analogy approach is one of the most popular dynamic mesh deformation methods. In the ball-vertex method, perpendicular linear springs are introduced to deal with the element collapse problem. However, it is not very efficient as a large system of linear equations has to be resolved. In order to overcome this difficulty, the Vertex-Ball Spring Smoothing algorithm (VerBSS) is proposed in this paper. Following the mesh smoothing concept, a sub-spring system derived from the “ball-vertex” model is built and solved on a node by node basis using an LDLT solver. Interior nodes are smoothed layer by layer in an iterative manner to achieve the best result. Parallel scheme is also introduced in the smoothing process for further improvement of the efficiency. Numerical examples in two and three dimensions show that VerBSS is much more efficient than the ball-vertex method, and is capable of dealing with practical engineering objects with complex geometries subject to large deformations. VerBSS can be applied to complicated mesh topologies as well, not only to 2D/3D dynamic mesh, but also to the hybrid dynamic mesh.

Genetic variation is thought to contribute to etiology of metabolic syndrome (MS). Neural precursor cell expressed developmentally downregulated 4-like gene (NEDD4L) is a candidate gene for MS. This study investigated the relationship between variations of NEDD4L and MS in the Kazakh, which is an ideal population to study the genetic mechanisms of complex diseases such as MS. We screened the promoter and exons of NEDD4L in 48 Kazakh individuals with MS to identify representative variations. By genotyping the representative variations [271420T>C (rs2288774), 271454A>G (rs2288775), and 296921-296923delTTG] in the Kazakh general population, we conducted a case-control study. In female subjects, the distribution of genotypes and alleles of rs2288775 and 296921-296923delTTG differed significantly between the MS pacients and controls. In male subjects, the genotype distributions of 296921-296923delTTG were significantly different between the MS pacients and controls in the dominant model (P = 0.047). After adjustment for age, smoking, and drinking, multivariate logistic regression analysis showed that rs2288775 was significantly associated with MS [for the A/A genotype, odds ratio (OR) = 3.296, P = 0.011] in female subjects. For 296921-296923delTTG, the I/D+D/D genotype was the high-risk genotype for MS in female subjects (OR = 2.791, P = 0.035) and was a protective factor for MS in male subjects (OR = 0.580, P = 0.045). The 296921-296923delTTG variation of NEDD4L is a gender flip-flop associated with MS in Kazakh individuals. The A allele of rs2288775 may be an independent risk factor for MS in Kazakh women. The results suggest that the genetic variations of NEDD4L might be involved in the pathogenesis of MS.

The free-standing GaN (FS-GaN) substrate was fabricated by using an in-situ self-separation technique that was accomplished by using the thermal decomposition of GaN. For the self-separation of GaN, a decomposable buffer layer (DBL) was introduced between the sapphire substrate and the overgrown thick-GaN, and self-separation of GaN happened during the high-temperature GaN growth. The thick GaN was almost unaffected by the thermal stress during the separation from sapphire substrate, so we could fabricate low-defect and high-quality FS-GaN. In this study, the DBL growth temperature (Tg: 700 ◦C) and the thermal annealing temperature (T ∼ 900 ◦C) were optimized. The reduced thermal stress was confirmed by using cathodoluminescence. Also, the values of the full widths at half maximum for the (002) and the (102) ω-rocking curves were 67 and 96 arcsec, respectively, and a low etch pit density (6 × 10 cm−2) was observed, both of which indicate the feasibility of this method for fabricating FS-GaN.

A well adherent copper deposit on the Mg alloy (AZ31) can be obtained with a pretreatment with galvanostatic etching then followed by copper electrodeposition in an alkaline copper-sulfate plating bath. Experimental results show that the effect of galvanostatic etching on copper electrodeposition depends strongly on potential variation during anodic etching period. Oxygen-rich Cu and Mg layers were observed in the initial stage of galvanostatic etching. However, increasing the gavanostatic etching period to the potential plateau of its anodic polarization curve, the oxygen-rich Cu and Mg layers were almost removed and an activated surface of AZ31 can be achieved, which is suitable for Cu electrodeposition in the alkaline Cu-sulfate plating bath. The above-mentioned results were evidenced from the microstructure study with scanning transmission electron microscope.

Microcantilever has been increasingly used as microsensor thanks to its fast response, low cost and parallel implementation in large quantity. The principle of sensing lies in the positive correlation between the resonant frequency of microcantilever and the target mass loading. The shape of cantilever determines the resonant frequency. Therefore it plays a vital role in microsensing. In the present study three basic geometric shapes (rectangle, triangle and half-ellipse) with innovative inner cut are investigated. The micro-cantilever beams are cut to external aspect ratios of 0.5, 1, and 2, and inner cut at aspect ratios of 0, 0.5, 1, and 2, with equal sensing area. Both numerical and experimental analysis indicates that the low-aspect-ratio cantilever with high-aspect-ratio inner cut achieved high sensitivity. The half-ellipse being the highest followed by the rectangle. The results are useful for optimal shape design of a micromechanical cantilever sensor.

Department of Nano-semiconductor Engineering, National Korea Maritime University, Busan 606-791, Korea*Department of Offshore Plant Management, National Korea Maritime University, Busan 606-791, Korea**Division of Electrical and Electronics Engineering, National Korea Maritime University, Busan 606-791, Korea***PAN-Xal Co., Ltd., Suwon 443-380, Korea****Center for Interdisciplinary Research, Tohoku University, Sendai 980-8577, Japan

A method of laser-activated deposition through the metabolite of Acidithiobacillus ferrooxidans is demonstrated. The experimental results indicate that the deposition process exhibits positive correlation to laser power and a negative correlation to scanning speed. The amount of deposition is related to the supplied energy per unit length of laser scanning. With respect to the thermal field on the substrate produced by a moving point source and a laser beam crossing a reference point, the temperature history and the accumulated energy are used to model the deposition process. The threshold temperature of the deposition is estimated 500 K, and the activation energy per unit volume of deposition of the process is about 120 pJ/μm 3 .

Photon emission and scattering are enhanced by the number of photons in the final state, and the photon transport equation reflects this in scattering–emission kernels and source terms. This is often a complication in both theoretical and numerical analyzes, requiring approximations and assumptions about background and material temperatures, incident and exiting photon energies, local thermodynamic equilibrium, plus other related aspects of photon scattering and emission. We review earlier schemes parameterizing photon scattering–emission processes, and suggest two alternative schemes. One links the product of photon and electron distributions in the final state to the product in the initial state by Jacobian transformation of kinematical variables (energy and angle), and the other links integrands of scattering kernels in a detailed balance requirement for overall (integrated) induced effects. Compton and inverse Compton differential scattering cross sections are detailed in appropriate limits, numerical integrations are performed over the induced scattering kernel, and for tabulation induced scattering terms are incorporated into effective cross sections for comparisons and numerical estimates. Relativistic electron distributions are assumed for calculations. Both Wien and Planckian distributions are contrasted for impact on induced scattering as LTE limit points. We find that both transformed and balanced approximations suggest larger induced scattering effects at high photon energies and low electron temperatures, and smaller effects in the opposite limits, compared to previous analyzes, with 10–20% increases in effective cross sections. We also note that both approximations can be simply implemented within existing transport modules or opacity processors as an additional term in the effective scattering cross section. Applications and comparisons include effective cross sections, kernel approximations, and impacts on radiative transport solutions in 1D geometry. The additional computing time for processing opacities (cross sections) within these approximations is negligible as induced terms are merely added (multipliers) to cross sections at the end of the processing cycle.

A B S T R A C T This study explores an innovative metal machining process by using bacteria. Acidithiobacillus ferrooxidans (At. ferrooxidans) was used to remove metal. The bacteria first carried out the oxidation of Fe 2+ to Fe 3+ . The produced Fe 3+ then oxidized the metals. The machining of copper, nickel and aluminum was experimentally investigated using both the cells and the culture supernatant of At. ferrooxidans. The material removal rates of these three metals were 2.0, 1.6, 0.55 and 5.5, 4.2 and 0.7 mg/h cm 2 by using cells and culture supernatant, respectively. Higher metal removal rate was achieved for copper by using the culture supernatant. A microbe-based fabrication of micropattern is thus feasible applying the current principle. 2012 CIRP.

In this paper, an energy parameter based on the concept of the M -integral is proposed for describing the fracture behavior of a multi-cracked solid subjected to nonconservative and nonuniform crack surface tractions. By using the M -integral with a suitably chosen closed contour, one can evaluate the ‘surface creation energy’ (SCE) required for creation of the stressed cracks. Also, it is demonstrated that the property of path-independence holds even under the action of crack surface tractions. Therefore, the singular stress field in the near-tip areas is not directly involved in the calculation so that a complicated finite element model around the crack tips is not required in evaluation of the M -integral.

The experiment described in this paper used vacuum induction melting (VIM) to coat Ni alloyNi alloy onto AISI 4140 steel. X-ray diffraction (XRD), scanning electron microscope (SEM), electron probe micro analyzer (EPMA), and transmission electron microscope (TEM) were used to identify the different phases of VIM Ni alloyNi alloys. Then, a ball-on-disc system and different dry sliding wear conditions were used to test VIM Ni alloyNi alloys. Results indicate that Ni 3 Si particles were scattered inside the γ-Ni solid solution, Ni 3 B and dendrite Ni 3 Si appeared in the lamellar structures, and Cr 7 C 3 and CrB were scattered in the lamellar structures of Ni 3 B and dendrite Ni 3 Si. Cr 7 C 3 and CrB were more wear resistant compared to other phases. The wear loss of VIM Ni alloys was lower when the sliding velocity was 0.1 m/s compared to when the velocity was 0.7 m/s. In the former case, the formation of a continuous oxidation layer protected the original surface from direct wear. A further increase in sliding distance caused, in both the cases, the formation of tumorous oxides, which led to delamination. Regardless, wear loss at 0.1 m/s was still lower than at 0.7 m/s.

An induction-melted Ni-based alloy (NiCrBSi) coating on AISI 4140 steel was prepared using induction melting under different melting conditions. To determine the microstructure and bonding behavior of their interfaces, the techniques of micro-diffraction, X-ray mapping and wavelength dispersive spectrometry (WDS) were employed. The experimental results showed that a white zone appears on the Ni-based alloy side of the final interface, becoming wider and wider with increasing temperature and time, which was identified as a solid solution of γ-Ni at 1000 °C and 1180 °C. A higher heating temperature and time caused a more severe iron dilution in the Ni-based alloy and decreased the microhardness.

A vacuum induction-melted (VIM) Ni-based alloy was immersed in 60% H2SO4 solution to investigate its corrosion behaviour and resistance. The results indicate that the microstructure contains a γ-Ni solid solution + Ni3Si particles, dendrite Ni3Si, Ni3B, Cr7C3, and CrB. The corrosion started at the zones of the γ-Ni solid solution + Ni3Si particles and dendrite Ni3Si. These zones transformed to oxide films and protected the alloy from significant attack. However, the pitting corrosion created paths for acid solution and/or SO 4 2 - to further attack. Therefore, the corrosion rate decreased and then stabilised at a high value as the immersion time increased.

We fabricated 10 ㎚-thick cobalt silicide(CoSi 2 ) as a buffer layer on a p-type Si(100) substrate to investigate the possibility of GaN epitaxial growth on CoSi 2 /Si(100) substrates. We deposited 500 ㎚-GaN on the cobalt silicide buffer layer at low temperature with a PA-MBE (plasma assisted-molecular beam epitaxy) after the CoSi 2 /Si substrates were cleaned by HF solution. An optical microscopy, AFM, TEM, and HR-XRD (high resolution X-ray diffractometer) were employed to determine the GaN epitaxy. For the GaN samples without HF cleaning, they showed no GaN epitaxial growth. For the GaN samples with HF cleaning, they showed 4㎛-thick GaN epitaxial growth due to surface etching of the silicide layers. Through XRD ω-scan of GaN direction, we confirmed the cyrstallinity of GaN epitaxy is 2.7° which is comparable with that of sapphire substrate. Our result implied that CoSi 2 /Si(100) substrate would be a good buffer and substrate for GaN epitaxial growth.Key Words : GaN, Epitaxy, PA-MBE, Cobalt Silicide Buffer, Silicon Substrate

In-doped ZnO (ZnO:In) nanocrystals with various In-contents have been successfully synthesized by vapor phase condensation of mixed source. Hexagonal phase ZnO:In samples with high In-concentration (∼25 at.%) were easily obtained and structural phase transformation was observed at ZnO:In nanocrystal with an In-concentration of ∼35 at.%. Near band edge (NBE) emission shifted to lower energy side and increase of emission intensity were observed from photoluminescence (PL) measurement, which was explained in terms of the increase of extrinsic carrier concentration. Diffuse-reflectance spectra (DRS) show free-carrier absorption band at 0.6-2.0 eV, which corresponds with the PL results.

A bimetal of Co-based alloy/AISI 4140 steel was fabricated by induction melting. The microstructure of the Co-based alloy was examined and the influence of on the alloy of acid solutions, the temperature of these solutions, and the immersion time was investigated. The results show that the microstructure of Co-based alloy consisted of a Co-rich phase, a Cr-rich phase, and W 3 CoB 3 . In a solution of 20% HCl and 6% FeCl 3 , the Co-rich phase was attacked to form porous channels but transformed to a Si-rich passivation film to prevent further attack in the solution of 72% H 2 SO 4 . Therefore, the relative corrosion resistance of Co-based alloy to acid solution is 72% H 2 SO 4 > 20% HCl > 6% FeCl 3 .