Thin film growth of epitaxial, polycrystalline and amorphous SrRuO3

The SrRuO₃ thin films were grown on amorphous fused silica and (100) single crystal LaAlO₃ substrates by pulsed laser deposition method. On fused silica substrates, polycrystalline SrRuO₃ thin film was obtained and below the crystallization temperature, SrRuO₃ thin films show an amorphous phase. For the case of epitaxial growth on (100) single crystal LaAlO₃ substrate, the crystallization temperature of SrRuO₃ thin film was increased by ∼ 100 °C indicating that additional energy is necessary in order to obtain the epitaxial thin film. By using the eclipse method and the control of substrate temperature, the variations of surface morphologies and grain size were observed by atomic force microscope. Below the crystallization temperature, amorphous SrRuO₃ thin film shows hopping transport property of an insulator.     

A hybrid PET‐MRI: An integrated molecular‐genetic imaging system with HRRT‐PET and 7.0‐T MRI

A PET‐MRI fusion system is developed for molecular‐genetic imaging. The purpose of the system is to obtain images of the in‐vivo human brain using two high‐end imaging devices, an advanced PET and an ultrahigh‐field MRI. These are the HRRT‐PET, a high‐resolution research tomograph dedicated to brain imaging on the molecular level, and the 7.0‐T MRI, an ultrahigh field version used for morphological imaging. HRRT‐PET delivers high‐resolution molecular imaging with a resolution down to 2.5 mm FWHM, which is currently the highest spatial resolution available for the observation of the human brain's molecular activities, including enzymes and receptors, which are manipulated genetically, such as reporter genes and probes. The 7.0‐T MRI began to reveal submillimeter resolution images of the cortical as well as deep brain areas, down to 250 μm, which allows us to visualize the fine details of the cortical and brainstem areas, including the line of Gennari in the visual cortex and the corticospinal tracts in the pontine area. The current PET‐MRI fusion imaging system produces the highest quality images of molecular and genetic activities of the human brain in vivo. It is starting to provide many answers to the key questions about the neurological diseases. Some of these start providing answers to many cognitive neuroscience problems with clear molecular and genetic bases. There is great potential in the PET‐MRI for early diagnosis of cancers as well as other neurological diseases, which we were previously unable to diagnose, such as microscopic molecular changes that occur in Parkinson's and Alzheimer's diseases. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 252–265, 2007     

A self-alignment crowned pulley design for high speed paper media transport systems

Misalignment of mechanical rolling elements such as belt and pulley causes catastrophic malfunctions of high speed paper feeding systems like automated teller machines (ATMs), printers, and copy machines. A combination of a crown pulley and a belt can be an effective self-alignment mechanism for the systems. In this paper, an equation of motion of the belt and pulley system is driven, verification tests are carried out, and a design improvement strategy is suggested for high speed paper media transport systems.     

Coordination of an SVC with a ULTC reserving compensation marginfor emergency control

This paper proposes a coordinated control scheme of an SVC (static VAr compensator) and a ULTC (under load tap changer) of a distribution substation to obtain a larger operating margin of SVC for emergency control. The conventional method can cause a lack of operating margin of SVCs in some conditions. It, however, is important to secure an operating margin for emergencies. In the proposed coordinated control system, SVC controls the voltage and ULTC responds to the SVC compensation value based on the relation between SVC compensation and ULTC tap position. In order to reserve the operating margin of the SVC, the time delay of ULTC is adaptively changed according to the operating condition of the SVC. Numerical simulations verify that the proposed system could increase the operating margin of SVC while improving the quality of load voltage     

Robust stability of Metzler operators under parameter perturbations

In this paper we study how the spectral bound of Metzler operators changes under parameter perturbations. Characterizations of the stability radii of Metzler operator with respect to this type of disturbances are established. The results generalize those obtained in (Vietnam J. Math. 2006; 34 :357–368; Vietnam J. Math. 1998; 26 :147–163). Copyright © 2009 John Wiley & Sons, Ltd.     

Characteristics of a parallel-plate waveguide with a narrow slit in its upper plate

A parallel-plate waveguide with a narrow slit in its upper plate is investigated. The magnetic current induced in the slit is obtained from an integral equation whose kernel is approximated to a logarithmic function. From knowledge of the magnetic current, the normalised conductance and susceptance of the slit are computed.     

Transcrystalline morphology and mechanical properties in polypropylene composites containing cellulose treated with sodium hydroxide and cellulase

To evaluate the transcrystalline effects caused by various fibers, which were untreated, or treated with sodium hydroxide and cellulase, isothermal crystallization was performed. It was observed that the untreated and cellulase-treated cellulose fibers (cellulose I) had a nucleating ability to transcrystallize at PP matrix. Especially, cellulose fibers treated with Sodium hydroxide (cellulose II) transcystallized at PP matrix. This result was different from other's. Cellulose fibers also transcrystallized at PP/MAH-PP matrix irrespective of the type of cellulose crystalline structure. In PP/MAH-PP/CELL system, MAH-PP was located around the fiber surface at initial crystallization time, but was gradually expelled from that with the increase of crystallization time, and existed at outer boundaries of transcrstalline region at the final crystallization time. These phenomena were confirmed by IR-IRS spectra. The tensile strength of PP/CELL and PP/MAH-PP/CELL composites decreased with the increase of isothermal crystallization time. Therefore, it is thought that transcrystallinity gives rise to negative effect of tensile strength.     

Design of RFID tag antenna for metallic surfaces using lossy substrate

A novel low-cost antenna design suitable for radio frequency identification (RFID) tags mountable on metallic surfaces is presented. The antenna consists of two shorted patches printed on a lossy FR4 substrate and their radiating edges are facing each other. A tag chip feed is placed between two patches and a stacked shunt capacitor is formed to adjust the antenna impedance. The proposed design reduces the substrate loss and improves the radiation efficiency by more than double compared with a conventional planar inverted-F antenna, which is verified by simulation and measurement.     

On pattern classification of EMG signals for walking motions

We present a method to calssify electromyogram (EMG) signals which are utilized as control signals for a patient-responsive walker-supported system for paraplegics. Patterns of EMG signals for different walking motions are classified via adequate filtering, real EMG signal extraction, AR-modeling, and a modified self-organizing feature map (MSOFM). In particular, a data-reducing extraction algorithm is employed for real EMG signals. Moreover, MSOFM classifies and determines the results automatically using a fixed map. Finally, the experimental results are presented for validation.     

Hydrogen production in fluidized bed by chemical-looping cycle

To investigate the feasibility of a chemical-looping hydrogen generation system, we investigated the reduction and water splitting reaction characteristics for three mediators and two reducing gas in a bubbling fluidized bed reactor (0.02 m I.D.). For three oxygen carrier particles (NiO/bentonite, Fe₂O₃/bentonite, (NiO:Fe₂O₃)/bentonite), hydrogen was used as a reduction gas and water was used as an oxidation gas. For (NiO: Fe₂O₃)/bentonite particle, carbon monoxide, which is the main component in the syngas from coal or heavy residue, was used as a reducing gas to check reactivity for the carbon containing fuels and carbon deposition characteristics. Based on the reactivity tests, (NiO: Fe₂O₃)/bentonite particle was selected as the best mediator for the chemical-looping hydrogen generation system to achieve stable continuous operation. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.