Advanced Materials Research Vol. 1096

Abstract: A novel structure of barrier controlled tunnel FET is proposed in the paper. The principles of gate work function engineering and channel doping engineering are combined to form up an in channel potential barrier, which can tune the source to drain tunnel current. The proposed structure serves as an alternative solution of barrier controlled tunnel FET fabrication, which combines the merits of the barrier controlled traditional MOSFET device and the bandgap controlled tunnel device. With carbon nanotube as the channel material, the device performance of the novel structure is verified using numerical simulation under the non-equilibrium Green’s function framework.

Abstract: In the analysis of semiconductor position sensitive detector (PSD) based on the traditional structure, using dual ion implantation method to studying the new type of PSD structure. The new structure of the n-type silicon substrate by implanting a high dose, low energy boron ions and another high energy boron ion, Which subsequent annealing of 2h at 1050 °C in an ambient of dry O₂ to form a shallow and a low doped p-n junction. Experimental results show that the new structure of PSD can obtained high position resolution, smaller errors and nonlinear response time.

Abstract: The mesoporous Ce_xZr_1-xO₂ mixed oxides with different Ce/Zr ratio were prepared via a surfactant-assisted method of nanoparticle assembly, CTAB was used as surfactant. The Ce_xZr_1-xO₂ mixed oxides were used as the supports for preparing Cr-V-O/ Ce_xZr_1-xO₂ catalysts by the wetness impregnation method, and the catalytic activities of the results catalysts for dehydrogenation of propane to propene were studied. The prepared catalysts were characterized by XRD and N₂ adsorption techniques.The Cr-V-O/ Ce_xZr_1-xO₂ catalysts exhibiting high activity and selectivity for dehydrogenation of propane to propene. The molar ratio of Ce/Zr ratio showed remarkable influence on the activity of the catalysts. The optimistic catalyst was Cr-V-O/Ce_0.5Zr_0.5O₂ the highest yield of 20.0% was obtained, the corresponding conversion of propane was 20.9% and selectivity to propene was 95.9% at 550 °C.

Abstract: A 600V-class lateral double-diffused metal-oxide-semiconductor (LDMOS) field-effect transistor with step-doped drift region (SDD) in partial silicon-on-insulator (PSOI) is introduced to improve breakdown voltage (BV) and reduce on-resistance (Ron). The step-doped method induces an electric field peak in the surface of the device, which can reduce the surface field in the device and adjust the doping accommodation in the drift region. The adjusted drift region can allow higher doping concentration under the drain end which results in higher breakdown voltage, and accommodate more impurity atoms as a whole which provides more electrons to support higher current and thus reduce on-resistance.

Abstract: The thermal conductivity at 300K of (6, 6) carbon nanotubes and chemi-adsorbed carbon nanotubes with methyl groups at random positions through covalent bonding (chemisorption) has been calculated as a function of adsorption density using molecular dynamics. The results exhibit a rapid drop in thermal conductivity with chemisorptions, even chemisorption as little as 1.0% of the nanotube carbon atoms reduces the thermal conductivity significantly. Investigate its reason, defects caused by chemisorption blocking the transmission of phonons which plays a leading role in the heat conduction of nanotubes, affecting the temperature distribution and energy transmission, leading to the thermal conductivity decline.

Abstract: Nanostructured materials have attracted considerable attention in recent years because of their unique and amazing properties. With a high surface activity due to their small particle size, enormous surface area and specific mechanical properties, it has been used for various engineering purposes including chemical, mechanical and civil engineering applications. The rapid development of nanostructured materials and nanotechnology will change the traditional processes of fabrication and applications of construction materials. nanosized materials can be used in construction industry to produce lighter and stronger structural composites such as modified steel. The present work introduces a novel idea for the production of metallic alloys from nanosized nickel ferrites using powder technique routes. nanosized nickel ferrite (50 nm) is being used as starting material for the production of metallic alloy containing iron and nickel. The prepared alloys were characterized physically and chemically through X-ray diffraction and optical microscope. The composition of these alloys is often a key factor to control the mechanical, chemical and physical properties of the synthesized alloys. The reduction processes take place in a stepwise manner via the formation of a series of intermediate oxides. The microstructures of the produced alloy together with the kinetics data obtained from reduction process were used to elucidate the reduction mechanism under isothermal conditions.

Abstract: The purpose of this paper is to discuss the merits and drawbacks of different phase change energy storage materials and investigate its application in buildings. The classification and integration of phase change energy storage materials into buildings were reviewed. Through years of research and development, these materials have found application in gypsum board, concrete and mortar. The problems in practical application and development direction of the future were put forward.

Abstract: Based on the test results of conductive properties of carbon fiber reinforced concrete, the main influence on content of carbon fiber, content of coarse aggregate, and carbon fiber length are discussed and analyzed. The test results show that when CF content reach the amount of 0.8%~1.2% by mass of cement, the factors have no significant effect on the fractional change in resistance under 0.5% of the significance levels. But when CF content reach the amount of 1.2%~2.0% by mass of cement, the factors show significant effect on the fractional change in resistance under 0.5% of the significance levels. The CFRC resistance can be taken the minimum only when the sand-cement ratio is 1.47, the CF nominal length is equal to 12mm and the CF content is accounted for 2.0% by weight of cement.

Abstract: This paper studies the engineering application of C80 concrete with the feasibility of the raw material and production process. According to the design principle of high strength concrete and the method of the orthogonal design, The C80 high-strength tri-admixture concrete which includes fly ash, slag and volatilized silica was developed by using the local admixture. Further, the results show that the designed of the high-strength concrete based on the local material is available by adjusting and optimizing the amount of admixture reasonably. At last, the green production goal is achieved by reducing the dosage of cement, consuming industrial waste materials which playing an important role in its activity.

Abstract: Based on ABAQUS general finite element software, UMAT Fortran subroutine is compiled to estimate the long-term deflections of prestressed concrete beams. And the calculated values using the software corresponded well with the laboratory results. By generalizing key parameters impact on long−term deflections of prestressed concrete beams, time-dependent finite element analysis was conducted. Taking type of concrete, concrete grade, age of concrete when the initial stress was applied, effective prestressing tensile force, type of prestressed tendon, reinforcement ratio for nonprestressed compression steel reinforcement and mean relative humidity into account, a simplified formula for long-term deflection of prestressed concrete beam at midspan was suggested. And the calculated values using the suggested formula corresponded well with the laboratory and filed test results. The errors were within 10%. However, the calculated errors using the common codes were larger, which resulted in the unsafe values.