Null-field BIEM for solving a scattering problem from a point source to a two-layer prolate spheroid

In this paper, the acoustic scattering problem from a point source to a two-layer prolate spheroid is solved by using the null-field boundary integral equation method (BIEM) in conjunction with degenerate kernels. To fully utilize the spheroidal geometry, the fundamental solutions and the boundary densities are expanded by using the addition theorem and spheroidal harmonics in the prolate spheroidal coordinates, respectively. Based on this approach, the collocation point can be located on the real boundary, and all boundary integrals can be determined analytically. In real applications of a two-layer prolate spheroidal structure, it can be applied to simulate the kidney-stone biomechanical system. Here, we consider the confocal structure to simulate the kidney-stone system since its analytical solution can be analytically derived. The parameter study for providing some references in the clinical medical treatment is also considered. To check the validity of the null-field BIEM, a special case of the acoustic scattering problem of a point source by a rigid scatterer is also done by setting the density of the inner prolate spheroid to infinity. Results of the present method are compared with those obtained using the commercial finite element software ABAQUS.     

Exact solutions for plastic responses of orthotropic strain-hardening rotating hollow cylinders

This paper presents exact solutions for plastic responses of plastically orthotropic strain-hardening rotating hollow cylinders. Hill’s yield criterion and the Voce hardening law were adopted. The concept of sequential limit analysis was employed to deal with the strain-hardening behavior by updating the yield criterion and the deformed configuration sequentially. First, exact solutions of the plastic angular velocity were acquired by solving both static and kinematic limit analysis problems. The existence of closed-form exact solutions for some cases was also illustrated. Moreover, the global hardening behavior was analytically evaluated. The corresponding distributions of plastic stress components and equivalent plastic strain were also developed. Second, the elastic–plastic capability of the commercial finite-element code ABAQUS was employed for rigorous validations of analytical solutions. Finally, good agreement is observed between analytical solutions and numerical results.     

Thermoelastic Analysis of Functionally Graded Rotating Disks with Variable Thickness Involving Non-Uniform Heat Source

The research aims to investigate thermoelastic behavior of functionally graded rotating disks with variable thickness involving a non-uniform heat source. We assume material properties and thickness of rotating disks to vary in the radial direction. Axisymmetric thermal loads including non-uniform heat source, heat flux, and temperature boundary conditions are considered. To conduct corresponding simulations, two user subroutines are edited and incorporated into the commercial finite-element code ABAQUS. For verification, analytical formulations are derived and solved uniquely by symbolic calculations using the computing software Mathematica. The developed finite-element technique is then verified with very good agreement between results by ABAQUS and Mathematica.     

Improved additive manufacturing of silicon carbide parts via pressureless electric field-assisted sintering

High solids loading silicon carbide (SiC)-based aqueous slurries containing only .5 wt. % organic additives were utilized to create specimens of various geometries via an extrusion-based additive manufacturing (AM) technique. Pressureless electric field-assisted sintering was performed to densify each specimen without deformation. The combination of these techniques produced parts with >98% relative density despite containing only 5 wt.% oxide sintering additives. After sintering, specimens contained only the α-SiC and yttrium aluminum perovskite phases. This suggests the evolution of a nonequilibrium yttrium aluminate phase, as well as transformation from β-SiC to α-SiC. The fabrication method presented in this work has advantages over other AM techniques commonly used with SiC, because it does not require significant organic additives nor additional postprocessing steps such as chemical vapor infiltration or polymer impregnation and pyrolysis.     

Temperature Change of Light Induced Explosion of explosive material

A theoretical analysis based on the adiabatic consideration of one- dimensional model for initiation of explosive materials by intense light is performed. An expression is obtained which can be used to calculate the explosion temperature.     

The Tumor Suppressor Roles of miR-433 and miR-127 in Gastric Cancer

The discovery of microRNAs (miRNAs) provides a new and powerful tool for studying the mechanism, diagnosis and treatment of human cancers. Currently, the methylation epigenetic silencing of miRNAs with tumor suppressor features by CpG island hypermethylation is emerging as a common hallmark of different tumors. Here we showed that miR-433 and miR-127 were significantly down-regulated in gastric cancer (GC) tissues compared with the adjacent normal regions in 86 paired samples. Moreover, the lower level of miR-433 and miR-127 was associated with pM or pTNM stage in clinical gastric cancer patients. The restored expression of miR-433 and miR-127 in GC cells upon 5-Aza-CdR and TSA treatment suggested the loss of miR-433 and miR-127 was at least partly regulated by epigenetic modification in GC. Furthermore, the ectopic expression of miR-433 and miR-127 in gastric cancer cell lines HGC-27 inhibits cell proliferation, cell cycle progression, cell migration and invasion by directly interacting with the mRNA encoding oncogenic factors KRAS and MAPK4 respectively. Taken together, our results showed that miR-433 and miR-127 might act as tumor suppressors in GC, and it may provide novel diagnostic and therapeutic options for human GC clinical operation in the near future.     

Specific Heat of Olive Oil to 356 MPa

We measured the velocity of sound in olive oil under pressure with the Brillouin light scattering technique. Using the values for the density and the thermal conductivity that have only recently been reported, we calculated the adiabatic compressibility and the isobaric specific heat up to 356 MPa and the thermal diffusivity up to 200 MPa. The specific heat displays a maximum at 124 MPa, suggesting a possible phase transition around this pressure. Apart from the theoretical and practical importance of these results for the food industry and beyond, this work shows that Brillouin light scattering and macroscopic methods are complementary and can be employed to measure thermophysical parameters of food liquids under pressure.     

Protective effects of fullerenol on carbon tetrachloride-induced acute hepatotoxicity and nephrotoxicity in rats

An important biologically-relevant property of fullerenol is its ability to quench free radicals. Carbon tetrachloride (CCl₄)-induced hepatotoxicity and nephrotoxicity model was used to investigate the possible mechanisms of fullerenol protection in Sprague-Dawley rats in this study. Rats were administrated with fullerenol (0, 1, 1.5 and 5 mg/kg d) by intravenous or intraperitoneal injection for 3 days before CCl₄ challenge, 24 h following the CCl₄ challenge, all the rats were assessed using serum and tissue homogenates biomarkers as well as the pathological evaluation. All results showed that CCl₄ caused significant increasing serum activity of alanine aminotransferase and aspartate aminotransferase, as well as the concentration of blood urea nitrogen and creatinine. Malondialdehyde level was also increased significantly, whereas the ratio of reduced glutathione to oxidized glutathione was decreased in tissue homogenates. The pathological evaluation indicated the liver and kidney were damaged by CCl₄. Fullerenol-pretreatment alleviated biomarker changes as well as histological changes significantly, and fullerenol-pretreatment alone can increase the ratio of reduced glutathione to oxidized glutathione, which indicated fullerenol could protect tissues against CCl₄-induced oxidative stress by improving the antioxidant ability.     

硅基PbSe／BaF2／CaF2薄膜及其光电特性

采用分子束外延方法在Si(111)衬底上生长了PbSe/BaF2/CaF2薄膜,扫描电镜和X－光衍射分析显示,通过生长BaF2/CaF2缓冲层的方法,在Si(111)衬底上外延的PbSe薄膜晶体质量高,PbSe表面光亮,无形裂现象发生,X－光衍射峰峰宽窄（153arcs)。外延生长的PbSe薄膜被应用于制作光电二极管,首次采用热蒸发金属铝膜在PbSe表面形成Al-PbSe肖特基结光电二极管,获得了比Pb-PbSe肖特基结更为稳定和理想的电流－电压特性曲线。     

Freeze-form extrusion fabrication of functionally graded materials

Presented in this paper is a novel additive manufacturing technology for making three-dimensional parts with functionally graded materials (FGMs), called Freeze-form Extrusion Fabrication (FEF). The system development included a triple-extruder mechanism, extruder modeling and control, pastes extrusion planning for desired composition gradients, and software coding for motion and extrusion control. The effectiveness of the developed FEF system was demonstrated first by fabricating limestone (CaCO₃) parts with graded colors and then by fabricating ‘green’ parts with graded compositions between alumina (Al₂O₃) and zirconia (ZrO₂). The fabricated part went through post-processing, and the sintered part was analyzed using energy dispersive spectroscopy (EDS) to determine its material compositions.