bluuebunny/crossref_metadata_2025 huggingface dataset:
Piezoelectric Properties of Sn-Doped (K,Na)NbO3 Ceramics
Authors: Ishii Hideki , Kawada Shinichiro , Suzuki Shoichiro , Honda Atsushi , Higai Shin'ichi , Hayashi Hiroyuki , Okuzawa Tadashi , Kimura Masahiko , Omiya Suetake , Kubodera Noriyuki , Konoike Takehiro
Published: October 2013

It was previously reported that Ca-doped (K,Na)NbO3 + ZrO2 could be cofired with nickel inner electrodes in a reducing atmosphere. In the present study, the piezoelectric properties of Sn-doped (K,Na)NbO3 + ZrO2 ceramics were investigated. We prepared Sn-doped (K,Na)NbO3 + ZrO2 ceramics and Ca-doped (K,Na)NbO3 + ZrO2 ceramics by doping with Sn2+ and Ca2+ under reducing calcination. The Curie temperature T
c of the Sn-doped (K,Na)NbO3 + ZrO2 was 300 °C, which was the same as that of the Ca-doped (K,Na)NbO3 + ZrO2. The tetragonal–orthorhombic phase transition temperature and piezoelectric constant d
33 of the Ca-doped (K,Na)NbO3 + ZrO2 were 130 °C and 130 pC/N while those of the Sn-doped (K,Na)NbO3 + ZrO2 were 50 °C and 190 pC/N, respectively. These results suggest that the piezoelectric d constant of (K,Na)NbO3-based multilayer ceramics with nickel inner electrodes can be increased by doping with Sn2+ instead of Ca2+.
Bendable Electro-Acoustic Transducer Fabricated Utilizing Frequency Dispersion of Elastic Modulus
Authors: Miyoshi Tetsu , Ohga Juro
Published: October 2013

To realize the speaker diaphragm that can be united with a flexible display without deteriorating lightweight properties and flexibility, a novel bendable electro-acoustic transducer (BEAT) based on 0–3-type piezoelectric composites has been developed. To overcome the trade-off between flexibility and the transmission efficiency of vibration energy, a viscoelastic polymer that has local maximum points in the loss factor as well as large frequency dispersion in the storage modulus near room temperature was employed as the matrix of the piezoelectric composite layer. Against the comparatively slow (10 Hz or less) deformation from the outside, the viscoelastic matrix is viscous enough to prevent cracking and delamination. On the other hand, in the audible range (20 Hz to 20 kHz), the matrix is elastic enough to transmit piezoelectric vibration energy, maintaining a moderately large loss factor as well as a high sound velocity. For the first time, we successfully demonstrated a rollable speaker that can continue to generate a high-quality sound while being rolled and unrolled repeatedly onto a cylinder with a curvature radius of 4 mm.
Improvement of Piezoelectricity of Poly(L-lactide) Film by Using Acrylic Symmetric Block Copolymer as Additive
Authors: Shiomi Yuki , Onishi Katsuki , Nakiri Takuo , Imoto Kenji , Ariura Fumi , Miyabo Atsushi , Date Munehiro , Fukada Eichi , Tajitsu Yoshiro
Published: October 2013

By using additives to change the higher-order structure of a poly(L-lactide) (PLLA) film, an improvement in its piezoelectricity was realized. The additive used was a triblock copolymer, which is a pure acrylic symmetric block copolymer consisting of a center block of poly(butyl acrylate) (PBA), corresponding to its soft part, and two side blocks of poly(methyl methacrylate) (PMMA), corresponding to its hard part. The triblock copolymer is hereafter denoted as PMMA-b-PBA-b-PMMA. The piezoelectric e-constant of the PLLA film with added PMMA-b-PBA-b-PMMA (PLLA/PMMA–PBA–PMMA film) was over two times higher than that of the PLLA film without adding PMMA-b-PBA-b-PMMA (reference PLLA film). Also, we found that the glass transition temperature increases with increasing PMMA-b-PBA-b-PMMA content. From atomic force microscopy (AFM) images, it was found that a new higher-order structure was formed in the PLLA/PMMA–PBA–PMMA film with high piezoelectricity. The method of using PMMA-b-PBA-b-PMMA has high productivity and its promising for industrial use.
Discontinuous Change in Density at Phase Transition in Antiferroelectric Liquid Crystal
Authors: Uehara Hiroyuki
Published: October 2013

Discontinuous changes in density (Δρ) at various phase transitions in an antiferroelectric liquid crystal, 4-(1-methylheptyloxycalbonyl)phenyl 4'-octyloxybiphenyl-4-carboxylate (MHPOBC), were estimated using published data and the Clausius–Clapeyron equation. The estimated Δρ at the SmCFI1
*–SmC* transition is about twice as large as that at the SmCA
*–SmCFI1
* transition. This result suggests that the changes in density at these phase transitions are related to the disappearance of the interdigitation of molecules. As a result of reconfirming the data for 4-(1-metylheptyloxycarbonyl) 3-fluorophenyl 4'-dodecylbiphenyl-4-carboxylate (MHFPDBC), a change in density of -2×10-5 g/cm3 was detected at the Ferri–SmC* transition in MHFPDBC.
Direct Observation of Ultraviolet-Induced One-Dimensional Vibration of Ti Ions in Red Phosphor Sr(Ti0.939,Al0.061)O3:Pr3+
Authors: Nakajima Nobuo , Deguchi Masataka , Maruyama Hiroshi , Osawa Hitoshi , Moriyoshi Chikako , Kuroiwa Yoshihiro
Published: October 2013

The ultraviolet-induced one-dimensional vibration of Ti ions in the red phosphor Sr(Ti0.939,Al0.061)O3:Pr3+ was successfully visualized using high-resolution X-ray diffraction, which was already predicted by X-ray absorption spectroscopy. The vibration of Ti 3d-eg states becomes clear with decreasing temperature, accompanied by the addition of blue-green luminescence intrinsic to SrTiO3 at low temperatures. These results clearly indicate that a weak coupling between photoexcited electrons and the T
1u phonon mode induces an anharmonic vibration of Ti ions.
Cation Distributions and Microwave Dielectric Properties of Spinel-Structured MgGa2O4 Ceramics
Authors: Kan Akinori , Moriyama Tohru , Takahashi Susumu , Ogawa Hirotaka
Published: October 2013

The Mg2+ and Ga3+ cation distributions in the MgGa2O4 lattice were characterized by the refinement of the crystal structure and the firing temperature dependence of microwave dielectric properties was described in this study. The crystal structure refinement of MgGa2O4 ceramics fired at different temperatures indicated that the degree of inversion x, which represents the Mg2+ and Ga3+ cation distributions in the 8(a) and 16(d) sites in (Mg1-x
Ga
x
)[Mg
x
Ga2-x
]O4, slightly decreases from 0.88 to 0.84 with increasing firing temperature from 1500 to 1600 °C. This implies that the Mg2+ cation preferentially occupies the 8(a) site, i.e., the tetrahedral site, with increasing firing temperature. The dielectric constant (εr) of the MgGa2O4 ceramics fired above 1520 °C was almost constant (εr = 9.2), whereas their Q·f significantly increased from 92,000 to 298,000 GHz, depending on the firing temperature. Such an increase in the Q·f may be related to the Mg2+ and Ga3+ cation distributions in the MgGa2O4 lattice.
Microholographic Optical Data Storage with Spatial Mode Multiplexing
Authors: Mikami Hideharu , Watanabe Koichi
Published: October 2013

Microholographic optical data storage is a promising candidate for next-generation optical disc systems because of its potential huge capacity. We proposed and demonstrated a new novel multiplexing technique for microholographic optical data storage using spatial modes of an optical beam to enhance data capacity. Numerical simulation was performed to validate the proposal and it was estimated that the net increase of data capacity by applying two- and four-mode multiplexing with Hermite–Gaussian modes was 1.3 and 1.7 times, respectively. A proof-of-principle experiment for two-mode multiplexing was performed by using spatial modes equivalent to Laguerre–Gaussian modes and it was demonstrated that signal output was selectively obtained by choosing an appropriate spatial mode for reference light of phase-diversity homodyne detection. Because the proposed technique can be applied in conjunction with other multiplexing and multilevel techniques, it is expected to greatly increase the possible applications of future optical disc systems.
Direct Observation of Peristrophic Multiplexing Holograms with a Phase Contrast Microscope
Authors: Inami Wataru , Kanamori Masaki , Kawata Yoshimasa , Ishii Norikiko , Kinoshita Nobuhiko , Muroi Tetsuhiko , Kikuchi Hiroshi
Published: October 2013

We present the direct observation of peristrophic multiplexing holograms. A phase microscope is used for visualizing refractive-index distributions in holograms. It may be used to image the variation of refractive index as contrast of the observed images with high microscopic resolution. We have successfully imaged the deformation of recorded holograms with nonuniformity and the shrinkage of a hologram medium. This is the first demonstration of the direct observation of a multiplexed hologram with a phase contrast microscope. We also demonstrated the Fourier-transform analysis of the observed images.
Focus Sensing Method Using Diffracted Waves to Position Spatially Phase-Modulated Beams for Collinear Holographic Data Discs
Authors: Fujita Teruo , Takamura Yuki
Published: October 2013

A focus sensing method using diffracted waves, which are produced by a one-dimensional grating embedded inside a hologram disc, to position spatially phase-modulated beams is proposed. Simulation has been performed to show the effectiveness of the proposed method and has given an offset-free and well-shaped focus error signal. This focus error signal can keep the distance between the focal position of the recorded hologram and the servo layer of the collinear holographic data disc and provides higher disc interchangeability and portability.
A Simple 2/3 Modulation Code for Multi-Level Holographic Data Storage
Authors: Kim Soo Youn , Lee Jaejin
Published: October 2013

We propose a simple 2/3 modulation code for multi-level holographic data storage (HDS). HDS is a promising method for the optical data storage system. However, two-dimensional (2D) inter-symbol interference (ISI) and inter-page interference (IPI) are weaknesses of HDS systems. Moreover, if multi-level symbols are stored, such systems are more vulnerable to errors. A modulation code can be used to alleviate these problems. Therefore, we introduce a simple 2/3 modulation code for multi-level HDS systems, which is simple and mitigates 2D ISI patterns.
Terahertz Emission from Resonant Tunneling Diodes without Satisfying Oscillation Condition
Authors: Asada Masahiro , Kanaya Hidetoshi , Suzuki Safumi
Published: October 2013

Terahertz (THz) emission from resonant tunneling diodes (RTDs) is normally obtained under the oscillation condition in which the negative differential conductance (NDC) exceeds the circuit loss. In this study, we show that a relatively broad band THz emission was observed even for RTDs with an NDC smaller than the circuit loss. The observed output power was on the order of 1–10 nW at 1.2–1.9 THz with spectral widths of 50–100 GHz. The observation was reasonably explained by the theoretical calculation based on the shot noise amplified by the NDC. This emission corresponds to the amplified spontaneous emission in optical devices.
Theory of Attenuated Total Reflection Including Effects of Roughness
Authors: Uehara Yoichi
Published: October 2013

We have developed a theory of attenuated total reflection applicable to multi-layered samples with roughness at surfaces and/or interfaces. Angle dependence of reflectivity for incident light with any polarization are expressed by a power series of profile functions of roughness, and the terms up to the second order polynomials of the profile functions are presented. Numerical analyses for Au films in the Kretschmann configuration reveal that differences between the predictions taking into account roughness and the ones assuming flat interfaces depend on both lateral and longitudinal sizes of roughness, and that the differences becomes not negligible for roughness greater than a certain level, e.g., roughness whose correlation lengthaand root-mean-square δ of the amplitude are 20 and 2 nm, respectively.
Experimental Observation of Quantum Confinement Effect in <110> and <100> Silicon Nanowire Field-Effect Transistors and Single-Electron/Hole Transistors Operating at Room Temperature
Authors: Suzuki Ryota , Nozue Motoki , Saraya Takuya , Hiramoto Toshiro
Published: October 2013

The quantum confinement effect (QCE) in ultranarrow silicon nanowire channel field-effect transistors (FETs) as well as single-electron/hole transistors (SET/SHTs) operating at room temperature is intensively investigated for the optimization of device design and fabrication. By adopting a “shared channel” structure with the directions of <110> and <100>, a carrier-dependent QCE is systematically examined. It is found that <110> nanowire pFETs exhibit a smaller threshold voltage (V
th) variability due to a weaker QCE, while <110> nFETs and <100> n/pFETs show comparable V
th variabilities coming from the QCE. It is also found that only SETs exhibit clear Coulomb oscillations in the case of the <110> channel, suggesting the formation of higher tunnel barriers than SHTs. On the other hand, <100> SHTs show undesirable multidot behavior in spite of their comparable QCEs for electrons and holes. It is concluded that <110>-directed nanowire channel SETs and n/pFETs are suitable for the integration of CMOS and SETs.
Inductively Coupled Plasma Mass Spectrometry Study on the Increase in the Amount of Pr Atoms for Cs-Ion-Implanted Pd/CaO Multilayer Complex with Deuterium Permeation
Authors: Hioki Tatsumi , Takahashi Naoko , Kosaka Satoru , Nishi Teppei , Azuma Hirozumi , Hibi Shogo , Higuchi Yuki , Murase Atsushi , Motohiro Tomoyoshi
Published: October 2013

To investigate the nuclear transmutation of Cs into Pr reported in this journal by Iwamura and coworkers, we have measured the amount of Pr atoms in the range as low as ∼1×1010 cm-2 using inductively coupled plasma mass spectrometry for Cs-ion-implanted Pd/CaO multilayer complexes before and after deuterium permeation. The amount of Pr was initially at most 2.0×1011 cm-2 and it increased up to 1.6×1012 cm-2 after deuterium permeation. The increase in the amount of Pr could be explained neither by deuterium permeation-stimulated segregation of Pr impurities nor by external contamination from the experimental environment during the permeation. No increase in Pr was observed for permeation with hydrogen. These findings suggest that the observed increase in Pr with deuterium permeation can be attributed to a nuclear origin, as reported by Iwamura and coworkers, although the amount of the increase in Pr is two orders of magnitude less than that reported by them.
Coulomb Logarithm Formulae for Collisions between Species with Different Temperatures
Authors: Honda Mitsuru
Published: October 2013

This brief note proposes the practically useful Coulomb logarithm formulae that can be applied to collisions between any particles in a plasma consisting of various species with different temperatures. The classical and quantum-mechanical formulae of the Coulomb logarithm are both derived and are seamlessly connected. Their wide and flexible applicability is suitable for implementation in numerical codes. The formulae proposed can recover the previously-known ones that are valid for specific cases.
Effect of Chloride Precursors on the Stability of Solution-Processed Indium Zinc Oxide Thin-Film Transistors
Authors: Lee Dong Hee , Park Sung Min , Yang Jung Il , Cho Dong Kyu , Woo Sang Hyun , Lim Yoo Sung , Kim Dae Kuk , Yi Moonsuk
Published: October 2013

In this experiment, solution-processed indium zinc oxide (IZO) films were prepared by spin-coating the films as an active layer in thin-film transistors (TFTs). These films were coated with nitrate and a mixture of acetate- and chloride-based precursors to allow the IZO films to contain indium and zinc components. The solution-processed IZO-based TFT fabricated using a zinc acetate precursor for the IZO films exhibited a mobility of 2.83 cm2V-1s-1, an on/off current ratio of ∼1×105, and a subthreshold swing value of 2.48 V/dec. The IZO-TFT with the zinc chloride precursor exhibited a mobility of 4.37 cm2V-1s-1, an on/off current ratio of ∼1×103, and a subthreshold swing value of 6.44 V/dec. In comparison, the IZO-TFT with a mixture of zinc acetate and chloride precursors exhibited a mobility of 1.45 cm2V-1s-1, an on/off current ratio of ∼1×105, and a subthreshold swing value of 1.83 V/dec. The first two devices suffered from a large threshold voltage (Vth) shift, >7 and >6 V, respectively, after a gate voltage of 20 V was applied for 2 h. In contrast, the device fabricated using the mixed precursors showed a higher stability, shifting about 1.7 V under the same stress conditions.
A Newly Designed Polyfluorene as an Efficient Host Material for Phosphorescent-Dye-Doped Polymer Light-Emitting Diodes
Authors: Ha Soo-Hyun , Noh Yong-Young
Published: October 2013

A newly designed polyfluorene derivative, poly[2,7-(9,9-bis(5-cyanopentyl fluorene)-co-alt)-2,5-dimethyl-phenylene] (CNPFX), was synthesized for use as a host material for a phosphorescent dye, fac-tris(2-phenylpyridine) [Ir(ppy)3], in phosphorescent polymer light-emitting diodes. Efficient energy transfer to Ir(ppy)3 was achieved as a result of improved chemical compatibility via introduction of a polar unit, as well as increased spectrum overlap due to a blue-shift in the emission spectrum. Photo- and electro-luminescent spectra of Ir(ppy)3-doped CNPFX film showed clear green emission from Ir(ppy)3 due to efficient energy transfer, whereas those of Ir(ppy)3-doped poly(9,9-dihexylfluorene) (PF6) film showed blue emission from PF6. The CNPFX:Ir(ppy)3 (8 wt %) single layer device showed significantly improved performance.
Carrier Injection Related Stability of Intrinsic Hydrogenated Amorphous Silicon Film and Solar Cells
Authors: Park Jinjoo , Kim Youngkuk , Iftiquar Shaikh Mohammad , Shin Chonghoon , Lee Sunwha , Jung Junhee , Yi Junsin
Published: October 2013

In this paper, we report the stability of hydrogenated amorphous silicon (a-Si:H) thin films and solar cells for various carrier injections. The intrinsic films were prepared with different hydrogen dilutions. We observed that the a-Si:H film had a 25.4% decline in photocurrent due to the carrier injection. The photoluminescence peak within 1.1 to 1.7 eV increased towards the lower photon energy, due to the bias stress. The Urbach energy for the film degraded from 59 to 85 meV under a similar condition. We also observed a 24% drop in efficiency of the solar cell, due to a forward bias stress for 10 h.
Fabrication and Characterization of Rapidly Oxidized p-Type Cu2O Films from Cu Films and their Application to Heterojunction Thin-Film Solar Cells
Authors: Kim Hyung Soo , Lim Jung Wook , Yun Sun Jin , Park Min A , Park Se Yong , Lee Seong Eui , Lee Hee Chul
Published: October 2013

In this study, we report that the metal Cu deposited on a glass substrate is formed into a stable p-type Cu2O film with excellent properties through rapid thermal oxidation (RTO). The pre-deposited Cu film layer went through thermal oxidation in the temperature range of 200–500 °C in O2 and air ambient, and the electrical and optical properties were intensively investigated. The optimized p-type Cu2O film heat-treated at a temperature of 200 °C in an air ambient has a carrier concentration of 1.25×1017 cm-3, mobility of 0.51 cm2 V-1 s-1, and resistivity of 9.86 Ω cm; its optical band gap reaches about 2.4 eV. Using the p-type Cu2O film with i- and n-type amorphous silicon layers, heterojunction thin-film solar cells were fabricated on glass substrates. These transparent solar cells employed Ga-doped ZnO films as top and bottom electrodes. Solar cells with Cu2O film oxidized at 200 °C in an air ambient have an open circuit voltage of 0.36 V, short-circuit current of 15.2 mA/cm2, and photoelectric conversion efficiency of 1.98%.
Piezoelectric Energy Harvester for Batteryless Switch Devices
Authors: Kim Min-Soo , Lee Sung-Chan , Kim Sin-Woong , Jeong Soon-Jong , Kim In-Sung , Song Jaesung
Published: October 2013

This study investigated a piezoelectric energy-harvesting system for a mechanical switch device. Piezoelectric ceramics of 0.4Pb(Mg1/3Nb2/3)O3–0.25PbZrO3–0.35PbTiO3 were prepared by using a conventional solid-state reaction method. Li2O, Bi2O3, and CuO additions were used as sintering aids to develop piezoelectric ceramics for low-temperature sintering. Multilayer piezoelectric ceramics with 10×10×3 mm3 sizes and with Ag–Pd inner electrodes were manufactured by using the conventional tape-casting method with the prepared powder. A prototype of a piezoelectric batteryless switch device using the multilayer ceramics was produced. It showed an output peak-to-peak voltage of 3.8 V and an output power per strike of 18 µW. The performance of the device was good enough for practical use.
Rare Earth Oxide Nanolayer Coating on ZnO Nanowires in Dye-Sensitized Solar Cells
Authors: Choi Seok Cheol , Yun Won Suk , Sohn Sang Ho
Published: October 2013

Rare earth ion-modified ZnO nanowires were grown in solutions with precursors (Ce, Gd, La, and Y) and their effects on the photoelectrochemical properties of dye-sensitized solar cells (DSSCs) were investigated. Rare earth ion modifications yielded an increase in the lattice constant of ZnO nanowires, causing a widening of their energy bandgap. Photocurrent density vs photovoltage characteristics show that the photoelectrochemical properties increase in the order of Gd, Y, La, none, and Ce ion-modified ZnO nanowire-based DSSCs. From the data of the absorbance, incident to photon-to-current efficiency (IPCE) and electrochemical impedance spectroscopy (EIS), it was found that DSSCs with Ce ion-modified ZnO nanowires exhibit better device performance in terms of V
oc, J
sc, and efficiency, suggesting that the element of precursor is a key parameter in DSSCs. The experimental results can be explained in terms of the Burstein–Mott effects, vertical growth, and rare earth oxide coating effects of the ZnO nanowires.
Effect of Post-Chemical–Mechanical Polishing Surface Treatments on the Interfacial Adhesion Energy between Cu and a Capping Layer
Authors: Kim Jeong-Kyu , Kang Hee-Oh , Hwang Wook-Jung , Yang Jun-Mo , Park Young-Bae
Published: October 2013

The effect of post-chemical–mechanical polishing (CMP) surface treatments on the interfacial adhesion energies between electroplated Cu thin film and SiN
x
capping layer was evaluated using a four-point bending test. The polished Cu surface was treated by one of three methods: no surface treatment, cleaning by plasma with a vacuum break, and cleaning by the wet chemical method. X-ray photoemission spectroscopy (XPS) analysis on the delaminated interfaces, cross-sectional high-resolution transmission electron microscopy (HR-TEM), and also the electron energy loss spectroscopy (EELS) analysis were performed on the interfaces. The interfacial adhesion energy increases with post-CMP cleaning, which is strongly influenced by the effective removal of residual oxygen at the Cu surfaces.
Investigation of Tungsten Nitride Deposition Using Tungsten Hexafluoride Precursor for Via and Plug Metallization
Authors: Hwang Yeong-Hyeon , Cho Won-Ju , Kim Yongtae
Published: October 2013

We investigated a tungsten nitride (WN)-based diffusion barrier layer (DBL) on a Cu metal layer by atomic layer deposition (ALD) using three different treatments, namely, ammonia (NH3) plasma treatment, ammonia (NH3) pulsed plasma treatment, and diborane (B2H6) pulsed gas injection treatment. In an experimental result of a method with B2H6 pulsed gas injection, the fluorine (F) concentration was below 3% in the WN films, and optimum growth conditions, including a linear deposition rate, a few incubation cycles, good thermal stability, and an excellent step coverage of approximately 100%, were observed for the DBL application. These results suggest that the B2H6 pulsed gas injection is a useful method for obtaining high-quality WN films for use as a DBL on a Cu contact via a 15 nm node.
Consecutive and Selective Chemical Vapor Deposition of Pt/Al Bilayer Electrodes for TiO2 Resistive Switching Memory
Authors: Park Heejung , Go Seunghee , Lee Chiyoung , Nam Hoseok , Lee Jong-Kwon , Lee Jaegab
Published: October 2013

This paper demonstrated a new method for consecutive and selective chemical vapor deposition (CVD) of Pt and Al on a TiO2 surface in the presence of a highly hydrophobic 1H,1H,2H,2H-perfluorodecyltrichlorosilane (PFS) monolayer. The printed PFS monolayers effectively served as a monolayer resist for the consecutive CVD of Al and Pt in the fabrication of the patterned, robust Pt/Al bilayer electrodes for TiO2 resistive switching random access memory (ReRAM) devices. The Al underlayer promoted the nucleation and the growth of the CVD Pt, and thus provided a base for a more uniform and thicker deposition of Pt than bare TiO2 surfaces. In addition, the enhanced adhesion of Pt with the additional Al layer significantly improved the endurance of the resistive switching TiO2 thin film. Thus this bottom-up approach may be well extended in the fabrication of next generation devices.
Direct Nanoimprint of Metal Bilayer for Tunnable Metal Photonic Properties
Authors: Sung Sangkeun , Kim Chul-Hyun , Choi Dae-Geun , Lee Jihye , Choi Jun-Hyuk , Lee Eung-Sug
Published: October 2013

Tunable metal optical properties were realized by directly nanoimprinting metal onto silver-coated poly(methyl methacrylate) (PMMA) bilayer glass substrates. Imprinting at elevated temperatures enabled the molding of a stamp pattern consisting of a hexagonal pillar array with a 265 nm diameter and 530 nm pitch size, which produced a corrugated-metal nanohole array. The transmittance of the sample imprinted at 200 °C and 50 bar was uniquely improved from below 20% to more than 30% in the visible–infrared region, and its reflectance was reduced by more than 65% compared to a reference sample. The optical properties of the investigated metal depended significantly on the imprint temperature and relatively less on the imprint pressure and deposited silver film thickness. The improved transmittance was obtained only for the direct-imprinted silver–PMMA and not when the silver was simply deposited onto the predefined PMMA pattern. The presented fabrication strategy enables the provision of accessible optical tunability as well as improved cost-labor effectiveness for metal nanostructuring.
Study of A-Site Disorder Dependent Structural, Magnetic, and Magnetocaloric Properties in La0.7-xSmxCa0.3MnO3 Manganites
Authors: Anwar Mohammad Shafique , Ahmed Faheem , Lee Seung Rok , Danish Rehan , Koo Bon Heun
Published: October 2013

We report studies on the magnetocaloric effect of samarium doped lanthanum manganites with different Sm-concentrations. Polycrystalline La0.7-x
Sm
x
Ca0.30MnO3 (0≤x≤0.3) samples were prepared using the conventional solid-state reaction method with phase purity and structure confirmed using X-ray diffraction. Temperature dependent magnetization measurements and Arrott analysis reveal first order ferromagnetic transition in parent sample and second order ferromagnetic transition in doped sample with Curie temperature decreasing progressively with increasing Sm concentration from ∼182 K for x = 0.05 to 109 K for x = 0.30. A large magnetic entropy change (∼1.75 J kg-1 K-1 at 0.5 T) has been observed in La0.7Ca0.3MnO3 sample, and is greatly suppressed as a function of disorder caused by Sm doping. This is ascribed to the gradual loss of first-order ferromagnetic transition. This investigation suggests that La0.7-x
Sm
x
Ca0.30MnO3 compounds can be used as a potential magnetic refrigerating material with wide range of temperature.
Optimizing Surface-Enhanced Raman Scattering-Active Au Nanostructures Coated on Indium-Doped Tin Oxide Glass by Combining Chemical Assembly and Electrodeposition Methods
Authors: Bu Yanru , Lee Sangwha
Published: October 2013

A combined strategy of chemical assembly and electrodeposition methods was used to prepare Au nanostructures as highly efficient surface-enhanced Raman scattering (SERS) substrates. Small Au colloids (3–5 nm) were firstly anchored on the amine-terminated indium-doped tin oxide (ITO) glass, followed by the electrodeposited growth of Au nanoparticles (NPs) using constant potential electrolysis. We systematically investigated the effect of deposition potentials and electrodeposited times on the morphology of Au nanostructures and their coupling states on the ITO glass. The isolated (unconnected) dense-packing Au nanostructure demonstrated highly efficient SERS signals of o-chlorothiophenol when compared to those of aggregated (connected) dense-packing Au nanostructure. SERS enhancement factor of isolated dense-packing Au nanostructure was calculated to be tenth order of magnitude higher than that of aggregated dense-packing Au nanostructure.
Photoresponses in Gold Nanoparticle Single-Electron Transistors with Molecular Floating Gates
Authors: Noguchi Yutaka , Yamamoto Makoto , Ishii Hisao , Ueda Rieko , Terui Toshifumi , Imazu Keisuke , Tamada Kaoru , Sakano Takeshi , Matsuda Kenji
Published: October 2013

We have proposed a simple method of activating advanced functions in single-electron transistors (SETs) based on the specific properties of individual molecules. As a prototype, we fabricated a copper phthalocyanine (CuPc)-doped SET. The device consists of a gold-nanoparticle (GNP)-based SET doped with CuPc as a photoresponsive floating gate. In this paper, we report the details of the photoresponses of the CuPc-doped SET, such as conductance switching, sensitivity to the wavelength of the incident light, and multiple induced states.
Growth of Nanowires by High-Temperature Glancing Angle Deposition
Authors: Suzuki Motofumi , Minamitake Haruhiko , Kita Ryo , Hamachi Kenji , Hara Hideki , Nakajima Kaoru , Kimura Kenji , Hsu Chia-Wei , Chou Li-Jen
Published: October 2013

We have demonstrated that nanowires of various metals, Ge, and Ga2O3can be grown by high-temperature glancing angle deposition (HT-GLAD). The nanowires of metals including Al, Cu, Ag, Au, Mn, Fe, Co, Ni, and Zn are self-catalyzed, while the nanowires of other materials such as Ge and Ga2O3are catalyzed by Au nanoparticles. However, once the nanowires start to grow, the growth modes of the HT-GLAD nanowires are fundamentally the same, i.e., nanowires with uniform diameter grow only when the vapor is incident at a very high glancing angle and reach a length larger than 1–8 µm even though the number of deposited atoms corresponds to the average thickness of 20–30 nm. This suggests that there is a universal growth mechanism for the nanowires grown by HT-GLAD.
Surface Morphologies and Optical Properties of Si Doped InGaN Multi-Quantum-Well Grown on Vicinal Bulk GaN(0001) Substrates
Authors: Sasaoka Chiaki , Miyasaka Fumito , Koi Tomoaki , Kobayashi Masahide , Murase Yasuhiro , Ando Yuji , Yamaguchi Atsushi A.
Published: October 2013

Morphological and optical properties of Si doped In0.07Ga0.93N multi-quantum-well (MQW) were studied on a vicinal bulk GaN(0001) substrate with low dislocation density. Surface morphology of InGaN MQW was sensitive to the misorientation direction due to the anisotropic step edge structure peculiar to a hexagonal crystal. Appropriate Si doping was useful to suppress instability of the step front and a well-aligned straight step structure was demonstrated for the misorientation direction of [11̄00] with Si doping of 5×1018 cm-3. Low temperature photoluminescence (PL) indicated that good luminescence properties were maintained under the wide range of doping concentration, while PL degradation was observed for heavily doped MQW's. The luminescence properties were discussed based on a self-consistent calculation of the electronic structure of Si-doped MQW's.
Integrated Square Wave Voltammetry Redox Sensor System for Electrochemical Analysis
Authors: Lim Byounghyun , Futagawa Masato , Takahashi Sou , Dasai Fumihiro , Ishida Makoto , Sawada Kazuaki
Published: October 2013

An integrated square wave voltammetry (SWV) redox sensor has been developed on the basis of a standard complementary metal–oxide–semiconductor (CMOS) process technology. The sensor consists of a square wave (SW) pulse generator, a voltage controller, and two electrodes for electrochemical analysis. Our proposed sensor is the first integrated sensor system of a SW pulse generator. Potassium ferricyanide solution was measured to obtain the characteristics of the proposed sensor. We confirmed that the dynamic ranges of potassium ferricyanide concentration and SW frequency were obtained from 0.6 to 6 mM and from 20 to 500 Hz, respectively. To verify the accuracy of the proposed sensor system, we performed a comparison between the fabricated sensor and an electrochemical analyzer.
Optical Measurement for Solid- and Liquid-Phase Sb2Te3 around Its Melting Point
Authors: Kuwahara Masashi , Endo Rie , Tsutsumi Kouichi , Morikasa Fukuyoshi , Tsuruoka Tohru , Fukaya Toshio , Suzuki Michio , Susa Masahiro , Endo Tomoyoshi , Tadokoro Toshiyasu
Published: October 2013

We have developed a system for measuring the complex refractive index of liquid- and solid-phase chalcogenide around their melting points. The system consists of a spectroscopic ellipsometer, an infrared heating system, and prism optics. As a container for the chalcogenide, we use a customized quartz cell, evacuated to several pascal level to avoid sample degradation. We adopted a measurement configuration that uses access from the bottom side, because a mirror-like surface which is necessary for optical measurement was naturally and easily created at the container bottom by gravity. We succeeded in observing the remarkable difference on the indices between liquid- and solid-phase Sb2Te3.
Polyampholyte acrylic latexes for tablet coating applications
Authors: Ladika Mladen , Kalantar Thomas H. , Shao Hui , Dean Stacey L. , Harris J. Keith , Sheskey Paul J. , Coppens Karen , Balwinski Karen M. , Holbrook Debora L.
Published: October 2013

Polyampholyte latexes can exist within a certain pH range as low‐viscosity aqueous dispersions, while upon a pH shift to the vicinity of the isoelectric point they undergo ionic coacervation. Three classes of coacervation latexes were synthesized and evaluated for their suitability for use in tablet coating applications. Pharmaceutical tablet coatings are commonly based on hydroxypropyl methyl cellulose, poly(vinyl alcohol), and acrylic polymers. Because of the high viscosity of their aqueous solutions, and to the consequent required low concentrations of the tablet coating polymers in the coating solutions to enable sufficiently low viscosity for effective spray application, the current commercial pharmaceutical tablet coating technology requires the removal of large amounts of water during the manufacturing process. In this work, films prepared from high‐solids, low‐viscosity coacervated acrylic latexes showed good hardness, very low tackiness, an excellent combination of optical properties, and very low water vapor permeability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40049.
Microbial heterogeneity affects bioprocess robustness: Dynamic single‐cell analysis contributes to understanding of microbial populations
Authors: Delvigne Frank , Goffin Philippe
Published: October 2013

Heterogeneity or segregation of microbial populations has been the subject of much research, but the real impact of this phenomenon on bioprocesses remains poorly understood. The main reason for this lack of knowledge is the difficulty in monitoring microbial population heterogeneity under dynamic process conditions. The main concepts resulting in microbial population heterogeneity in the context of bioprocesses have been summarized by two distinct hypotheses. The first involves the individual history of microbial cells or the “path“ followed during their residence time inside the process equipment. The second hypothesis involves a coordinated response by the microbial population as a bet‐hedging strategy, in order to cope with process‐related stresses. The respective contribution of each hypothesis to microbial heterogeneity in bioprocesses is still unclear. This illustrates the fact that, although microbial phenotypic heterogeneity has been thoroughly investigated at a fundamental level, the implications of this phenomenon in the context of microbial bioprocesses are still subject to debate. At this time, automated flow cytometry is the best technique for investigating microbial heterogeneity under process conditions. However, dedicated software and relevant biomarkers are needed for the proper integration of flow cytometry as a bioprocess control tool.
Lipid bilayer arrays: Cyclically formed and measured
Authors: Lu Bin , Kocharyan Gayane , Schmidt Jacob J.
Published: October 2013

Artificial lipid bilayers have many uses. They are well established for scientific studies of reconstituted ion channels, used to host engineered pore proteins for sensing, and can potentially be applied in DNA sequencing. Droplet bilayers have significant technological potential for enabling many of these applications due to their compatibility with automation and array platforms. To further develop this potential, we have simplified the formation and electrical measurement of droplet bilayers using an apparatus that only requires fluid dispensation. We achieved simultaneous bilayer formation and measurement over a 32‐element array with ∼80% yield and no operator input following fluid addition. Cycling these arrays resulted in the formation and measurement of 96 out of 120 possible bilayers in 80 minutes, a sustainable rate that could significantly increase with automation and greater parallelization. This turn‐key, high‐yield approach to making artificial lipid bilayers requires no training, making the capability of creating and measuring lipid bilayers and ion channels accessible to a much wider audience. In addition, this approach is low‐cost, parallelizable, and automatable, allowing high‐throughput studies of ion channels and pore proteins in lipid bilayers for sensing or screening applications.
Screening for cardiac HERG potassium channel interacting proteins using the yeast two‐hybrid technique
Authors: Ma Qingyan , Yu Hong , Lin Jijin , Sun Yifan , Shen Xinyuan , Ren Li
Published: October 2013

The human ERG protein (HERG or Kv11.1) encoded by the human ether‐a‐go‐go‐related gene (herg) is the pore‐forming subunit of the cardiac delayed rectifier potassium current (IKr) responsible for action potential (AP) repolarization. Mutations in HERG lead to long‐QT syndrome, a major cause of arrhythmias. Protein–protein interactions are fundamental for ion channel trafficking, membrane localization, and functional modulation. To identify proteins involved in the regulation of the HERG channel, we conducted a yeast two‐hybrid screen of a human heart cDNA library using the C‐terminus or N‐terminus of HERG as bait. Fifteen proteins were identified as HERG amino terminal (HERG‐NT)‐interacting proteins, including Caveolin‐1 (a membrane scaffold protein with multiple interacting partners, including G‐proteins, kinases and NOS), the zinc finger protein, FHL2 and PTPN12 (a non‐receptor tyrosine phosphatase). Eight HERG carboxylic terminal (HERG‐CT)‐interacting proteins were also identified, including the NF‐κB‐interacting protein myotrophin, We have identified multiple potential interacting proteins that may regulate cardiac IKr through cytoskeletal interactions, G‐protein modulation, phosphorylation and downstream second messenger and transcription cascades. These findings provide further insight into dynamic modulation of HERG under physiological conditions and arrhythmogenesis.
Characteristics of human adipose mesenchymal stem cells isolated from healthy and cancer affected people and their interactions with human breast cancer cell line MCF‐7 in vitro
Authors: Trivanović Drenka , Nikolić Srdjan , Krstić Jelena , Jauković Aleksandra , Mojsilović Slavko , Ilić Vesna , Okić‐Djordjević Ivana , Santibanez Juan Francisco , Jovčić Gordana , Bugarski Diana
Published: October 2013

Adipose tissue is an attractive source of mesenchymal stem/stromal cells (MSCs) with potential applications in reconstructive plastic surgery and regenerative medicine. The aim of this study was to characterise human adipose tissue MSCs (ASCs) derived from healthy individuals and cancer patients and to compare their interactions with tumour cells. ASCs were isolated from adipose tissue of healthy donors, breast cancer‐adjacent adipose tissue of breast cancer patients and tumour‐adjacent adipose tissue of non‐breast cancer patients. Their proliferation, differentiation, immunophenotype and gene expression were assessed and effects on the proliferation of human breast cancer cell line MCF‐7 compared. ASCs from all sources exhibited similar morphology, proliferative and differentiation potential, showing the characteristic pattern of mesenchymal surface markers expression (CD90, CD105, CD44H, CD73) and the lack of HLA‐DR and hematopoietic markers (CD11a, CD33, CD45, Glycophorin‐CD235a), but uneven expression of CD34. ASCs also shared a common positive gene expression of HLA‐DR, HLA‐A, IL‐6, TGF‐β and HIF‐1, but were negative for HLA‐G, while the expression levels of Cox‐2 and IDO‐1 varied. All ASCs significantly stimulated the proliferation of MCF‐7 tumour cells in direct mixed co‐cultures and transwell system, although their conditioned media displayed antiproliferative activity. Data obtained showed that ASCs with similar characteristics are easily isolated from various donors and sites of origin, although ASCs could both suppress and favour tumour cells growth, emphasising the importance of cellular context within the microenvironment and pointing to the significance of safety studies to exclude any potential clinical risk of their application in regenerative medicine.
QM/MM Molecular Modeling and Marcus Theory in the Molecular Design of Electrodes for Enzymatic Fuel Cells
Authors: Vazquez‐Duhalt Rafael , Aguila Sergio A. , Arrocha Andrés A. , Ayala Marcela
Published: October 2013

New and environmentally friendly technologies are needed for the fabrication of small devices able to produce electricity for biomedical and electronic applications. Enzymatic fuel cells are promising devices for micropower sources operating under mild conditions. The electron transfer (ET) between the redox‐active site of the protein and the electrode surface is a key issue that should be considered in the design of enzymatic fuel cells. The rational molecular design and the optimization of direct ET is still a challenging goal in the bioelectrochemical field. This review discusses the use of Marcus theory and hybrid quantum mechanics/molecular mechanics (QM/MM) modeling techniques to describe and predict the intramolecular ET between enzymes and electrode surfaces for the design of more efficient enzymatic electrodes and enzymatic fuel cells.
Microbial n‐butanol production from Clostridia to non‐Clostridial hosts
Authors: Branduardi Paola , de Ferra Francesca , Longo Valeria , Porro Danilo
Published: October 2013

In the context of the global objective of shifting from petroleum to a biomass‐based economy, the research on fermentative strategies to produce alternative biofuels and chemicals has become a predominant field of study. Microorganisms, because of their substrate versatility and metabolic efficiency, are promising to partially support our increasing needs for materials and fuels, opening up scenarios for the use of alternative sources, including wastes. Butanol is a very attractive molecule since it can be seen both as a chemical platform and as a fuel. Today, it is principally derived from petroleum, but it also represents the final product of a microbial fermentation. Although Clostridia are the natural and traditional organisms employed in butanol production, systematic approaches to improve production and resistance traits are currently impeded by a lack of characterization and genetic tools. This is the main reason why, besides their optimizations, a significant and growing amount of research is centered on the engineering of alternative robust cell factories capable of elevated production, possibly combined with higher tolerance. Here, we review the most recent advances in n‐butanol production in non‐Clostridial microbial hosts, including not only other prokaryotic but also eukaryotic microorganisms, which might eventually be seen as second‐generation hosts.
Soot Cake Oxidation on a Diesel Particulate Filter: Environmental Scanning Electron Microscopy Observation and Thermogravimetric Analysis
Authors: Kameya Yuki , Lee Kyeong O.
Published: October 2013

The oxidation behavior of soot cake on the porous wall of a diesel particulate filter (DPF) was investigated. As a new experimental approach to observe the soot cake during its oxidation, an environmental scanning electron microscope (ESEM) was utilized. The dynamic deformation process of the soot cake was revealed, and the contact conditions between the soot cake and the DPF wall, which is important in catalytic soot oxidation, were examined. In addition, thermogravimetric analysis (TGA) was performed and the specific reaction rate was determined. The effect of gas diffusion into the soot cake on the overall oxidation reaction rate was demonstrated. The soot cake oxidation behavior was discussed based on the ESEM observation and TGA results.
Advances in the research on Carboniferous deep‐water marine deposits in western Junggar, northwestern China
Authors: Zong Rui‐Wen , Fan Ruo‐Ying , Gong Yi‐Ming
Published: October 2013

Carboniferous deep‐water marine strata have been insufficiently studied in western Junggar, NW China where the deep‐water facies successions have long been disputed in terms of age constraints, sequence and palaeoenvironmental reconstruction. This paper introduces some views in the light of new materials obtained from this region in recent years. The presence of the Visean plant fossils from the upper Ta'erbahatai Formation in the Tarbgatay Mountains indicates that the formation can be extended to the Early Carboniferous epoch in age. This unit also displays obvious diachroneity, which is of Late Devonian to Early Tournaisian age in the Saur Mountains and Late Devonian to Visean age in the Tarbgatay Mountains. The Xibeikulasi, Baogutu and Tailegula formations are widely distributed in northwestern Karamay areas. The scouring structures and graded bedding near the boundaries between the three formations confirm the stratal sequence that they were originally assigned, namely the Xibeikulasi, Baogutu and Tailegula formations in ascending order. The ‘fossil chaos’ of the three formations is due to mistaking fossils of other stratigraphic units for fossils of these three formations. After revision, only the Early Carboniferous fossils are considered reliable, and combined with the newly found plant fossils, the Xibeikulasi, Baogutu and Tailegula formations are re‐assigned to the early Visean, late Visean, and latest Visean to Serpukhovian ages, respectively. An extension of the lower Hala'alate Formation was recognized in the southwestern Hala'alate Mountains. The presence of the latest Early Carboniferous brachiopods constrains the Hala'alate Formation as late Serpukhovian to Bashkirian in age, bearing the mid‐Carboniferous boundary. Copyright © 2013 John Wiley & Sons, Ltd.
EOQ Model: The Case in Which the Placing of Orders Is Rewarded
Authors: Marimon Frederic , Llach Josep
Published: October 2013

The first models of optimization of inventory management costs have undergone few changes since they were developed at the beginning of the last century. It is only with the passage of time that new scenarios have appeared with the introduction of new systems of production, and consequently of new strategies in the logistics chain. In this article, we analyze and propose a revision of the basic inventory model of economic order quantity first defined by Harris in 1913 for a scenario in which the owner of the stock receives a bonus or reward each time he replenishes his stock. This situation arises when the supplier receives a benefit (which he then shares with the customer) when managing his stock replenishment. An array of nested models is shown to illustrate this scenario, from which the constraints of previous scenarios have been removed. The model provides insights into the negotiation of batch size between supplier and buyer in a win‐win environment in the specific situation in which the supplier gives a bonus to the buyer at each stock replenishment. © 2011 Wiley Periodicals, Inc.