Synthesis and Characterization of Naphthalene End-Capped Divinylbenzene for OTFT

An organic field-effect transistor was fabricated based on a thin film of 1,4-bis-(2-naphthalen-2-ylvinyl)benzene (BNDV). The organic semiconductor was deposited via thermal evaporation on a chemically modified silicon dioxide surface. The thermal, optical, electronic, and surface properties of the BNDV compound were investigated by thermogravimetric analysis, differential scanning calorimetry, ultraviolet–visible (UV–vis) absorption, photoluminescence spectroscopies, cyclic voltammetry, x-ray diffraction, and atomic force microscopy. The BNDV had good oxidation stability and exhibited a field-effect performance with a mobility of 0.062 cm²/V s, a subthreshold slope of 0.4 V, and an on/off ratio of 2.45 × 10⁵.     

Kinetic model of glycerol chlorination with hydrochloric acid

A new reaction model for dichloropropanol (DCP) synthesis from glycerol chlorination is proposed based on the models reported by Tesser et al. (2007) and Luo et al. (2009). Two reaction steps, glycerol to glycerol-1-acetate and α-MCP to 3-chloropropandiol-1-acetate, were defined as reversible reactions and other reaction steps were defined as irreversible processes. Using the experimental data reported by Luo et al. (2009), the values predicted in this study were compared with the previous model reported by Luo et al. (2009) using both the average absolute deviation (AAD) and root mean square deviation (RMSD). The AAD and RMSD of the new model were 31% and 33% lower than that of the existing one, respectively. Overall, the proposed model for glycerol chlorination is superior to the previous model.     

CBR Revision Model for Improving Cost Prediction Accuracy in Multifamily Housing Projects

For any construction project to succeed, it is very important to accurately estimate the construction cost during the project’s initial stage. This is why there has been much interest lately in cost prediction models that use case-based reasoning (CBR). It has been pointed out, however, that existing CBR-based cost prediction models may yield inaccurate results even though they could survey optimal similar cases, if the number of cases in the case base is not enough. As opposed to the existing CBR-based construction cost prediction models, this study developed a CBR revision model that reflects the “revise” phase of the CBR cycle (retrieve, reuse, revise, and retain) based on nine multifamily housing projects executed recently by “A” Housing Corporation. To verify the developed model, a case study was performed using three case projects completed by “B” and “C” Housing Corporations. The result showed that the prediction error ratio after the Revise (I) phase decreased from 97.44 to 22.58%. This model can be effective when there are insufficient established cases in the case base.     

Polyester polyol synthesis by alternating copolymerization of propylene oxide with cyclic acid anhydrides by using double metal cyanide catalyst

Ring-opening copolymerizations of propylene oxide (PO) with cyclic acid anhydrides, succinic anhydride (SA), maleic anhydride (MA) and phthalic anhydride (PA) were carried out in the presence of a double metal cyanide (DMC) catalyst of molecular formula Zn_2.3Cl_1.0[Co(CN)₆]_1.0?2.0^tBuOH?1.0H₂O as a means of developing functional polyols bearing ester backbones. Uniform alternating copolymers are produced when [PO]/[anhydride] in the copolymer approaches unity. All resulting copolymers have moderate molecular weights (M_n = 2300–10,600) and a narrow polydispersity index (1.02–1.49). The apparent reactivity ratio of PO is 0.34, 0.28, and 0.26 for PO/SA, PO/MA, and PO/PA copolymerizations, respectively, assuming that the reactivity ratio of the anhydrides is zero. The DMC-catalyzed PO copolymerizations with anhydrides are an efficient way to produce polyester polyols, expanding the versatility of conventional polyols.     

Acoustic characterization of AlN films using a High Overtone Bulk acoustic wave resonator

Abstract

Using the composite resonator with additional thick AlN film with the FWHM of rocking curve of 2.53° under investigation, the bulk acoustic wave attenuation constant and sound velocity along c-axis were directly measured. The method of High Overtone Bulk acoustic wave Resonator (HBAR) spectroscopy based on frequency, measurements of the positions of the resonator peculiarities of phase and amplitude of electromagnetic wave reflection coefficient from composite resonator structure was applied. The method provides attenuation and velocity measurement in a wide frequency band, using the same sample. For the measurements, standard and modified HBAR spectroscopy based on the analysis of only parallel resonance properties of composite resonator structures were used.     

Age-related deficits in auditory confrontation naming.

The naming of manipulable objects in older and younger adults was evaluated across auditory, visual, and multisensory conditions. Older adults were less accurate and slower in naming across conditions, and all subjects were more impaired and slower to name action sounds than pictures or audiovisual combinations. Moreover, there was a sensory by age group interaction, revealing lower accuracy and increased latencies in auditory naming for older adults unrelated to hearing insensitivity but modest improvement to multisensory cues. These findings support age-related deficits in object action naming and suggest that auditory confrontation naming may be more sensitive than visual naming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Backward-motion control of a mobile robot with n passive off-hooked trailers

A passive multiple-trailer system provides various practical advantages for multi-functional service robots. However, motion control is difficult because the kinematic model is highly nonlinear. The kinematic design of a trailer system was proposed in prior research of ours. In this paper, it is shown how the backward motion of a robot with n passive trailers can be controlled. Once the desired trajectory of the last trailer is computed, the control input of the pushing robot is obtained through the proposed control scheme. Some experimental issues on reversing the trailer system are addressed. This paper provides an answer to the following question: “Does the system work well even if there are sensing or modeling errors?” Although it is difficult to obtain general analytic solutions for the above research question, a practical answer will be explored though simplified analysis and experiments. Experimental verifications are carried out using a mobile robot with three passive trailers. The experimental results show that backward-motion control can be successfully carried out by applying the proposed control scheme.     

Bias-error reduction in nanometer resolution microscopic motion tracking vision systems

Microscopic Motion Tracking Systems utilize sub-pixel algorithms to achieve close to nanometer precision motion measurement. This paper characterizes the bias-error of template matching image registration techniques which are commonly used to achieve this level of sub-pixel accuracy. An accurate functional expression for such bias error is derived, which shows how the error depends on image content. Furthermore, this expression is directly utilized in a bias reduction scheme that is shown to significantly reduce the bias error. The newly derived expressions and reduction schemes for bias are applied to a Microscopic Vision System that measures micro-object motion with close to nanometer resolution.     

One-step large-scale synthesis of micrometer-sized silver nanosheets by a template-free electrochemical method

We have synthesized micrometer-sized Ag nanosheets via a facile, one-step, template-free electrochemical deposition in an ultra-dilute silver nitrate aqueous electrolyte. The nanosheet growth was revealed to occur in three stages: (1) formation of polygonal Ag nuclei on a substrate, (2) growth of {112}-faceted nanowire from the nuclei, and (3) anisotropic growth of (111)-planar nanosheets, approximately 20 to 50 nm in thickness and 10 μm in width, in the <112>−direction. The vertical growth of the facet nanowire was induced by the strong interface anisotropy between the deposit and electrolyte due to the ultra-dilute concentration of electrolyte and high reduction potential. The thickness of Ag nanosheets was controllable by the adjustment of the reduction/oxidation potential and frequency of the reverse-pulse potentiodynamic mode.     

The public's value of hydrogen fuel cell buses: A contingent valuation study

With the increasing interest in global warming, there has been intense international competition with regard to the introduction of the hydrogen (H₂) fuel cell (FC) bus, which represents a promising solution for the low-carbon age. With respect to the investment in H₂-based technology development and the expansion of H₂ FC vehicles, the consumer attitude is a crucial factor because the Korean government will consider it one of the most important factors in its decision to approve a large-scale introduction of H₂ FC buses. In this regard, this study measures the public's willingness to pay (WTP) for a large-scale introduction of H₂ FC buses in Korea by employing a survey approach termed the contingent valuation. Furthermore, to enhance statistical efficiency, this study employs the one-and-one-half-bound dichotomous choice method. The annual mean WTP estimate was KRW 4230 (USD 4.55) per household as of 2007. The estimate of the annual benefits to the affected residents was KRW 32.3 billion (USD 34.7 million). The results of this study are expected to be helpful in policy decisions related to the introduction of H₂ FC buses and investment in H₂ technology development.