Effects of the composition of sputtering target on the stability of InGaZnO thin film transistor

In this study, we investigated the electrical characteristics and the stability of amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) from the viewpoint of active layer composition. Active layers of TFTs were deposited by r.f. sputtering. Two kinds of sputtering targets, which have different compositional ratios of In:Ga:Zn, were used to make variations in the active layer composition. All the fabricated IGZO TFTs showed more excellent characteristics than conventional amorphous silicon TFTs. However, in accordance with the Ga content, IGZO TFTs showed somewhat different electrical characteristics in values such as the threshold voltage and the field effect mobility. The device stability was also dependent on the Ga content, but had trade-off relation with the electrical characteristics.     

An experimental study on oil discharge ratio at inverter-driven high shell pressure scroll compressor using R410A/PVE

In this study, the oil discharge characteristics of a high shell pressure scroll compressor, which uses R410A as the refrigerant and PVE as the oil, were measured according to the conditions for oil management. The measurement of oil discharge ratio (ODR) in the system is very important to secure the operational reliability. It was made in real time through the refractive index sensor. ODR was greatly influenced by the mass flow rate and the dynamic viscosity of the refrigerant. As the rotation frequency of the compressor became higher, ODR increased rapidly. ODR at 120 Hz was 4.22 times higher than that at 60 Hz. At the same rotation frequency of the compressor, the increase of the suction pressure also played a role in increasing the ODR. In addition, in the zone where the ODR increased rapidly, the compressing efficiency of the compressor decreased significantly.     

Experimental evaluation and performance enhancement prediction of desiccant assisted separate sensible and latent cooling air-conditioning system

CO₂ and R410A desiccant wheel (DW)-assisted separate sensible and latent cooling (SSLC) air-conditioning systems were tested under the AHRI standard. At a 50 °C regeneration temperature, the coefficient of performance (COP) of the vapor compression cycles improved only 7% from the respective baseline systems for both refrigerants. This paper proposed the idea of applying divided condensers (or gas coolers) to the R410A (or CO₂) SSLC system to enhance its performance. It was found that the application of divided heat exchangers to the SSLC system provided sufficiently hot airflow for regenerating the desiccant wheel at both a reduced high side pressure (from 10.4 MPa to 9.7 MPa for CO₂, from 3.46 MPa to 3.45 MPa for R410A) and a reduced discharge temperature from the condenser (gas cooler) (4 K lower for both refrigerants). The COP improvement is 36% and 61% to R410A and CO₂ baseline systems, respectively.     

Porous Hybrid Network of Graphene and Metal Oxide Nanosheets as Useful Matrix for Improving the Electrode Performance of Layered Double Hydroxides

Mesoporous hybrid network of reduced graphene oxide (rG‐O) and layered MnO₂ nanosheets could act as an efficient immobilization matrix for improving the electrochemical activity of layered double hydroxide (LDH). The control of MnO₂/rG‐O ratio is crucial in optimizing the porous structure and electrical conductivity of the resulting hybrid structure. The immobilization of Co‐Al‐LDH on hybrid MnO₂/rG‐O network is more effective in enhancing its electrode activity compared with that of on pure rG‐O network. The Co‐Al‐LDH?rG‐O?MnO₂ nanohybrid deliveres a greater specific capacitance than does MnO₂‐free Co‐Al‐LDH?rG‐O nanohybrid. The beneficial effect of MnO₂ incorporation on the electrode performance of nanohybrid is more prominent for higher current density and faster scan rate, underscoring the significant enhancement of the electron transport of Co‐Al‐LDH?rG‐O. This is supported by electrochemical impedance spectroscopy. The present study clearly demonstrates the usefulness of the porously assembled hybrid network of graphene and metal oxide nanosheets as an effective platform for exploring efficient LDH‐based functional materials.     

In situ fabrication of platinum/graphene composite shell on polymer microspheres through reactive self-assembly and in situ reduction

We present a simple method to fabricate a uniform-sized graphene–metal–polymer composite microsphere of core–shell structure. On the surface of amine-functionalized polymer microsphere, graphene oxide (GO) sheets were affixed to give a core–shell structure by self-assembly process followed by the immobilization of platinum (Pt) ions to the assembled GO shell. Subsequently, they were chemically reduced in situ converting both GO and Pt ions to reduced GO (RGO) and Pt nanoparticles (NPs), respectively. As a result, a robust RGO-Pt composite shell, composed of RGO sheets and well-distributed Pt NPs, was fabricated on the microsphere surface. Meanwhile, the insulative GO shell was converted to the conductive RGO-Pt shell giving 24.0 S m^?1 of electrical conductivity. We demonstrated that the electrical property of the shell was significantly improved by the incorporation of Pt NPs.     

Hybrid neuro-fuzzy approach to the generation of measuring points for knowledge-based inspection planning

A knowledge-based inspection planning system is presented that can generate effective and consistent inspection plans automatically. The knowledge-based inspection planning system integrates part geometry information, tolerance information and heuristic knowledge of experienced inspection planners to determine the numbers and positions of measurement points. The system receives the tolerance information from users and stores it in the common database with 3D CAD geometry. A set of fuzzy rules and membership functions is automatically extracted from historic learning data using a hybrid neuro-fuzzy method. After the fuzzy rules are generated by the hybrid neuro-fuzzy model, a genetic algorithm is applied to optimize the weight parameters to find the best values for the constants. The proposed knowledge-based inspection planning system provides the stable and consistent inspection plan by removing the subjectivity of a human planner.     

Probing of human implicit intent based on eye movement and pupillary analysis for augmented cognition

The ultimate purpose of augmented cognition is to enhance human cognitive abilities, which are intrinsically limited. To enhance limited human cognitive abilities, we developed a human augmented cognition system that can offer appropriate information or services by actively responding to the user's intention. This article mainly describes a framework for probing human implicit intentions for the purpose of augmented cognition. The type of user intention, either task‐free human implicit intention or task‐oriented human implicit intention, can be predicted based on fixation count, fixation length, and pupil size variation induced by eye response. Further, these features are used to detect the transition point between task‐free human implicit intention and task‐oriented human implicit intention. Maximum a Posteriori in Naïve Bayes classification model is used for selecting relevant query keywords to search and retrieve specific information from a personalized knowledge database. The experimental results show that the proposed human intention recognition and probing models are suitable for achieving the goal of augmented cognition. © 2013 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 23, 114–126, 2013     

Continuous Coaxial Electrohydrodynamic Atomization System for Water‐Stable Wrapping of Magnetic Nanoparticles

An electrohydrodynamic atomization (EHDA) system that generates an electrospray can achieve particle formation and encapsulation by accumulating an electric charge on liquid flowing out from the nozzle. A novel coaxial EHDA system for continuous fabrication of water‐stable magnetic nanoparticles (MNPs) is established, based on a cone‐jet mode of electrospraying. Systemic variables, such as flow rates from dual nozzles and inducing voltages, are controlled to enable the preparation of water‐soluble MNPs coated by polysorbate 80. The PEGylated MNPs exhibit water stability. The magnetic resonance imaging potential of these MNPs is confirmed by in vivo imaging using a gastric cancer xenograft mouse model. Thus, this advanced coaxial EHDA system demonstrates remarkable capabilities for the continuous encapsulation of MNPs to render them water‐stable while preserving their properties as imaging agents.     

Analysis and optimal control of discrete time‐varying systems Via Hahn polynomials

Abstract

Recently, the problem of analysis and optimal control of discrete time‐invariant systems has been extensively studied using finite series expansion of discrete orthogonal polynomials. This paper is to extend the applicable scope of discrete orthogonal polynomials to discrete time‐varying systems. The finite set of Hahn polynomials {q_ik)], i=0, 1, …, N} is chosen as the finite series expansion basis due to its general form and useful properties. First, for treating the product of two discrete‐time functions by Hahn series expansion, a new algorithm is derived to compute the Hahn series expansion coefficients of products qi(k)q_j (k), i, j=0, 1, …, N. These Hahn coefficients are then used to establish a product operational matrix for relating the Hahn coefficient vector of a product function to those of its component functions. This product operational matrix, along with the relations for connecting the Hahn coefficient vectors of a discrete function x(k) and its time‐shifted x(k+1), is finally applied to derive computational algorithms for solving the problems of analysis and optimal control of discrete time‐varying systems via finite Hahn series. Computed results are provided to illustrate the applicability of the proposed algorithms.