The effect of Cu-sites doping on electrical properties of La2CuO4 as thermoelectric material

The electrical conductivity and thermoelectric power for solid solutions of La₂Cu_0.9M_0.1O₄ (M = Mn, Fe, Co and Ni) prepared by polymeric precursor synthesis were measured between 300 and 1173 K to test its suitability as a thermoelectric material. Fe-, Mn-and Ni-doped compositions exhibited a metal-semiconductor transition with decreasing temperature, whereas Co doping showed a semiconducting behaviour in the entire temperature range of measurement. With Cu-sites doping in La₂CuO₄, power factors were not enhanced.     

3-Dimensionally Integrated Planar Optics for 100 Gb/s Optical Packet Address Detection

We propose a novel planar optical interconnection scheme for 100 Gb/s optical packet address detection, which consists of waveguide grating couplers and a diffractive microlens integrated on a glass substrate 3-dimensionally. Length and duty cycle of the grating couplers have been determined on the bases of the ray-optic propagation-mode analysis in a slab waveguide and of the rigorous coupled-wave diffraction analysis for out-coupled radiation-modes. The 3-dimensionally integrated planar optics makes it possible to connect each address bit-signals of TE₀-waveguide mode to the detector with a power uniformity of 6.4 % and a total coupling efficiency of 72.3 %.     

The effect of casting conditions on the formation of longitudinal surface crack in the beam blank caster

To understand the effects of casting conditions on the formation of longitudinal surface crack, the crack morphology of over 2000 charges at scarfed beam blanks were investigated. The results whow that the most sensitive crack susceptibility range of carbon contents lie in the 0.12–0.13 wt.% range. This was due to the effect of shell irregularity between mold surface and solidified shell withdrawn by δ-γ transformation and the embrittlement phenomena by liquid film of soluble elements such as phosphorous and sulfur at the dendrite interface. It was found that the increase of crack formation is attributed to the increase of phosphorous and sulfur contents segregated at the dendrite interface. The increase of crack formation with increasing Phosphorous and Sulfur contents is due to the enlargement of the ΔT range, which is defined as the temperature difference between LIT (liquid impenetrable temperature) and ZDT (zero ductility temperature). The effect of casting speed on crack formation shows a linear relationship. As casting speed is increased, the solidified shell had little time to grow and the width of shell became smaller. As, the heat flux from the thinner shell increased, the thermal strain was increased, increasing crack formation.     

Sliding Mode Control of Cable-Stayed Bridge Subjected to Seismic Excitation

The working group on bridge control within the ASCE Committee on Structural Control recently initiated a first-generation benchmark problem addressing the control of a cable-stayed bridge subjected to seismic excitation. Previous research examined the applicability of a LQG-based semiactive control system using magnetorheological (MR) dampers to reduce the structural response of the benchmark bridge and confirmed the capability of the MR damper-based system for seismic response reduction. In this paper, sliding mode control (SMC) is applied in lieu of the LQG formulation to the benchmark bridge problem. The performance and robustness of the SMC-based semiactive control system using MR dampers (SMC/MR) is investigated through a series of numerical simulations, and it is confirmed that SMC/MR can be very effectively applied to the benchmark cable-stayed bridge, subjected to a wide range of seismic loading conditions.     

Intelligent Stock Portfolio Management System

Abstract: For the selection of stock portfolios, the optimiastion models or expert systems are used separately. To take advantage of both approaches, the integration of optimisation model and expert system is attempted. The proposed architecture—ISPMS (Intelligent Stock Portfolio Management System)—accomplishes the integration by interpreting the knowledge as a part of the formulation of optimisation model. The other generic issues in ISPMS are the integration of personal preference with the expert knowledge and knowledge acquisition by machine learning. This paper thus describes the representation and the inference of an expert knowledge, the representation of personal preference and its integration with the expert knowledge, the interpretation of the knowledge and preference to associate with optimisation model, and the solution algorithm of the modified optimisation model accordingly.     

Marangoni Flow Driven via Hole Structure of Soluble Acene–Polymer Blends for Selective Nitrogen Dioxide Sensing

The correlations between semiconductor type and gas sensing properties in soluble acene/polymer blends have not yet been examined. Here, the phase separation mechanism in pseudo-liquid phase blend film is investigated and an unusual solid-state morphology that is effective for amperometric gas sensing performance is demonstrated. In 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS–pentacene)/poly(fluorine-co-triarylamine) (PTAA) blend, two phases are uniformly mixed, without being completely phase-separated due to the similar solubility and surface tension. On the other hand, in 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (diF–TES ADT)/PTAA blend, the diF−TES ADT molecules are segregated both at the air–film, and film–substrate interfaces, and subsequently crystallized with a high degree of crystal perfection. In the meanwhile, Marangoni-flow induces crater-like via hole structure of PTAA at the middle layer. In situ measurement of (ultraviolet–visible) UV–vis absorption spectra and computational calculation reveal kinetics of liquid–solid–crystal transition in relation to the functional groups of soluble acene. Interestingly, flow driven hole structure of PTAA in diF–TES ADT/PTAA blend film allows the target NO₂ gas to selectively penetrate the channel region, thereby enhancing sensitivity toward NO₂, while decreasing affinity with other gases. The results provide protocols for fabricating highlperformance field-effect transistors and gas sensors in a blending system.