Advanced Materials Research Vols. 535-537

Abstract: We utilized Deoxyribonucleic acid (DNA) strands immobilized between a metal gap and its behavior was investigated. The DNA strands were initially prepared using the PCR method while gaps of 10.00 μm lengths were created on gold layer deposited onto silicon substrate. Once immobilized, current-voltage characterization was carried out on the Au-DNA-Au structure fabricated under the presence and absence of magnetic field. Experimental results clearly highlight the behavior of the DNA strands similar to semiconductor materials. An exponential decrease observed in the current in presence of external magnetic field suggests possible future application as a magnetic sensor.

Abstract: The integral theory for electromagnetic theory of gratings, which has complex mathematical tool and long computation cost, is needed to improve computing speed of the algorithm. A very shot-cut equation, which is called symmetrical equation of diffracted wavevectors by us, is presented. It makes the number of Green’s function expansion terms shorter and simplifies the integral kernel by taking into account its symmetry. Take the grating in Littrow mount for computing example, because of applying this equation, the computation cost of integral theory which has good convergence, is shorten to 1/2 to 2/5. This work modifies the integral theory and improves its computing speed.

Abstract: This work studies the two-photon luminescence spectra of a Yb³⁺ doped YAG crystal grown using the Czochralski method. To study the spectral performance of a 50 at.% Yb:YAG crystal, intense green light (centered at about 544nm) was generated by the crystal upon excitation using a 973nm InGaAs LD pump source. The luminescence spectra were obtained for various Yb concentrations and the emission intensity were plotted versus Yb³⁺ concentration. The green emission light attributed to Yb³⁺ two-photon transition.

Abstract: Embedded solid lubricant materials have good self-lubrication characteristics, which can realize lubrication in special some situations such as low-speed, high-load, high-temperature of the machinery without lubricating oil or grease. This paper presents a review concerning the structure of embedded solid lubrication materials, and its lubricating mechanism, the development of embedded solid lubricant materials, the latest research progress of the influence factors such as different types of metal substrates, mosaic, temperature, load, and porous structure and the application example of bearings. The feasibility of embedded solid lubrication materials which may be used in the mechanical seal face is also analyzed.

Abstract: Luminescent ternary organic-inorganic-polymeric mesoporous hybrid material Eu-(PA-SBA-15)-PMAA was prepared in situ through hydrothermal and solvothermal method based on hydrolysis and co-polycondensation. The organic ligand PA (O-phthalic anhydride) was modified by silane coupling reagent APS ((3-aminopropyl) triethoxysilane) to generate the precursor PA-Si which was used to form the ordered inorganic Si-O networks through direct co-hydrolysis and co-polycondensation process with SBA-15 in the presence of Pluronic P123 surfactant as a template. TEOS (tetraethoxysilane) was used to promote the hydrolysis and condensation process. Eu3+ complex Eu(PA-Si)3 was covalently linked to the ordered mesoporous SBA-15 and organic polymer PMMA which was synthesized by addition polymerization reaction of the monomer MMA (methyl methacrylate) in the presence of the initiator BPO (benzoyl peroxide). Moreover, the binary organic-inorganic mesoporous hybrid material Eu (PA-SBA-15)3 without polymer was also synthesized simultaneously for comparison. The luminescence properties of the hybrids were characterized in detail. The results show the ternary hybrid exhibits stronger emission intensity, longer lifetime and higher quantum efficiency than binary one which proves that the introduction of the organic polymer PMMA brings improvement to the hybrid system.

Abstract: Base on the blending modification and the toughness reinforcing method,choosing the thermoplastic poly-ether-polyurethane as the glue stocks of the inner layer, reinforcing the intension of the fiber layer,using the thermoplastic polyurethane and EPDM blending test，imprvoing the production technology of the inner layer and the outer layer,making imprvoing for the wear-resistant of layflat polyurethane hose.

Abstract: The postbucking behaviors of Functionally Graded Material (FGM) plate in hygrothermal environments are investigated. The material properties of FGM change continuously in the thickness direction according to the volume fractions of the materials. The formulations are based on the First-order Shear Deformation Theory (FSDT) and von Karman strain-displacement relations are applied. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. Newton-Raphson technique is adopted to analyze the thermal postbuckling behavior of the model. Furthermore, moisture effects on the model are significantly appeared due to the increase of the volume fraction index of the materials.

Abstract: Acrylate modified waterborne polyurethane (PUA) emulsion was prepared by means of core-shell polymerization processes. The structures and properties of emulsions were characterized by FTIR, TEM and DSC. The effects of polymerization temperature, the type and amount of initiator and the acrylic amount on the properties of emulsions were investigated. The experimental results showed that the emulsions prepared were core-shell composite, when the polymerization temperature was 70~75 °C, using oil-soluble initiator azobisisobutyronitrile (AIBN), and the percentage of AIBN was 2.0%~ 2.5%, the properties of the emulsion can be better, and the water resistance, stability and mechanical properties of the PUA films were improved increasingly.

Abstract: In order to study the influence of factors on the released anion concentration, the factors include the fiber content of negative oxygen ions, warp and weft density, organizational structure and friction time. Fabrics for A and B series were blended with modified polyester negative oxygen ions fiber and viscose fiber in different blending ratio. The released anion concentration were tested and analyzed. From the test results, following conclusions can be gotten. 1) In the same circumstance of other process conditions, with increasing of negative oxygen ions fiber content, the released anion concentration increased; 2) The honeycomb weave fabric B5 released the highest anion concentration in the other same process conditions, while plain weave fabric B1 released the least concentration; 3) More negative oxygen ions were produced when the warp and weft density were greater; 4) As the time of friction increased, the released anion concentration of fabric was increased until it reached a stable value; 5) Organizational structure had a great effect on releasing anion concentration through friction between woven fabric of negative oxygen ions and other knitted fabric. When the organization structure had bumpy effect, it was more conducive to release negative oxygen ions.

Abstract: Reinforced soil has been among the most effective soil modification materials. Its use has been expanded rapidly into civil engineering, geotechnical engineering and pavement engineering. Reinforcing subgarde in pavement systems has always been an issue. This study focuses on effect of paper inclusion on the modulus of elasticity of subgrade material. Paper was used for this investigation. Paper contents and aspect ratio have been changed during these tests. The paper percentage varied from 0 % (for unreinforced samples) to 20%. Silty sand was used as sub grade material. Unconfined compression tests were carried out to investigate behaviour of the composite under different condition. The paper reinforcment length and paper reinforcment content found to play important rule on the modulus of elasticity of paper reinforced samples. Furthermore it was observed that ductility of sample increased by paper inclusion.