bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-Temperature Sintering and Microwave Dielectric Properties of Ba2Ti9O20 Ceramics with CaO–B2O3–ZnO Glass Additions
Authors: Lin Huixing , Hu Lili , Zhao Xinagyu , Chen Wei , Luo Lan
Published: June 2011

The effect of CaO–B2O3–ZnO (CBZ) glass on the microstructures and microwave dielectric properties of Ba2Ti9O20 ceramics was investigated. With the addition of CBZ glass, the densification temperature of Ba2Ti9O20 can be effectively reduced from 1400 to 880–920 °C. It is found that the addition of CBZ glass (20–30 wt %) can significantly improve the density and dielectric properties of Ba2Ti9O20 ceramics. The dielectric properties of Ba2Ti9O20 ceramics were strongly dependent upon the amount of CBZ glass addition. A dielectric constant (εr) of 27.0, a quality factor (Q ×f) value of 13,400 GHz, and a temperature coefficient of resonant frequency (τf) of 17.8 ppm/°C were obtained for 20 wt % CBZ glass-doped Ba2Ti9O20 ceramics sintered at 920 °C for 2 h.
Electrode Effects on Dielectric Relaxation in Oxide-Ion Conductor Ce0.7Yb0.3O2-δ Having a Fluorite-Type Structure
Authors: Yagi Yuhji , Satake Jun , Saito Miwa , Yamamura Hiroshi
Published: June 2011

The frequency dependences of the dielectric constant (εr') for the oxide-ion conductor Ce0.7Yb0.3O2-δ with two types of electrode, Pt and La0.6Sr0.4FeO3-δ (LSF), were successfully explained by the superposition of polarizations due to charging currents and Debye-type dipoles of the dopant–vacancy associates, [YbCe'–VO
••]• and [YbCe'–VO
••–YbCe']×. The magnitudes of polarizations of the associates were very large for the sample with the Pt electrode, but were smaller by one or two orders of magnitude for the sample with the LSF electrode. The bulk and grain-boundary resistivities in the impedance spectra of Ce0.7Yb0.3O2-δ, which ought to be invariable regardless of the type of electrode used, showed a large difference between the samples with Pt and LSF electrodes. As a result, the impedance spectra were also explained by the Debye-type dipoles of the dopant–vacancy associates.
Correlation between Adhesive Strength and the Oxidized and Reduced States of Pt Films Electron Cyclotron Resonance Plasma Sputtered on SiO2
Authors: Akazawa Housei
Published: June 2011

Electron cyclotron resonance plasma sputtering of Pt with an O2/Ar gas mixture produced (111) oriented films with a surface roughness of ∼1 nm and resistivities between 20 and 27 µΩ cm. Continuous reduction of deposited film by Ar plasma is responsible for the formation of metallic Pt crystallites even under the presence of O2. The Pt(111) film was more adhesive to the substrate than that of Pt(200) film that was produced by post annealing magnetron-sputtered PtO
x
films. The Pt(111) films composed of columnar texture domains could be reversibly reduced or oxidized through annealing in a vacuum or in an O2 ambient, and the corresponding adhesive strength changed for one order of magnitude. The enhanced adhesion in the oxidized state was due to Pt films being softened by partial oxidation at the grain boundaries and the interface being immersed with oxygen species, which prevented chipping and cracking that are preludes to delamination.
Nonlinear Behavior of Decrease in Reflectivity of Multilayer Mirrors for Extreme Ultraviolet Lithography Optics by High-Flux Extreme Ultraviolet Irradiation in Various Vacuum Environments
Authors: Niibe Masahito , Koida Keigo , Kakutani Yukinobu , Nakayama Takahiro , Terashima Shigeru , Miyake Akira , Kubo Hiroyoshi , Matsunari Shuichi , Aoki Takashi , Kawata Shintaro
Published: June 2011

To estimate the optics lifetime of an extreme ultraviolet lithography (EUVL) system with a contaminated mirror surface, it is indispensable to carry out an acceleration test using high-flux EUV irradiation. In this study, Mo/Si multilayer mirrors were irradiated in various vacuum environments using a contamination evaluation system with an undulator light source, and changes in their reflectivity were evaluated. The dependence of the decrease in reflectivity per unit dose on the EUV irradiance was observed in high-flux irradiation experiments in vacuum with water vapor or n-decane gas introduction at pressures lower than about 10-5 Pa. The irradiance dependence disappeared when the pressures were increased for both water vapor and decane gas. A reflectivity distribution with a doughnut shape, namely, high at the irradiation center, low in the surrounding area, and high in the non-irradiated area, was observed in the irradiation experiments during the simultaneous introduction of water vapor and decane gas. These results can be generally explained by the mechanism of the supply-controlled limit.
Low Energy Xe+ Ion Beam Machining of the Ultralow Expansion Glass Substrates for Aspherical Extreme Ultraviolet Lithography Projection Optics
Authors: Endo Hironori , Yamada Junya , Pahlovy Shahjada A. , Miyamoto Iwao
Published: June 2011

Aspherical substrates for extreme ultraviolet lithography (EUVL) optics require an ultrahigh shape accuracy of less than 0.15 nm rms and a high-spatial frequency roughness (HSFR; spatial wavelength: less than 1 µm) of 0.12 nm rms. Generally, the ultra low expansion glass (ULE®) substrate with HSFR of 0.06–0.08 nm rms can be produced by mechanical machining methods. However, it is difficult to obtain the shape accuracy of less than 0.12 nm rms using mechanical machining methods. Therefore, ion beam figuring (IBF) may be adapted to final shape correction of the substrates for the projection optics of EUVL tools. In this study, we investigated the HSFR and machining rate of the ULE® substrate machined by a 0.3–1.0 keV Xe+ ion beam at off normal ion incidence angles and obtained the following results: the HSFRs of the ULE® substrate machined by a 1.0 keV Xe+ ion beam at a ion incidence angle of lower than 30° and a 0.3–0.5 keV Xe+ ion beam at an ion incidence angle of 0–45° are below 0.12 nm rms, which is smaller than the required HSFR specification of EUVL projection optics. From our experimental result and discussion, we concluded that the scan fine beam and tilt target mode smoothing for processing of the ULE® substrate meets the required specification of the HSFR (0.12 nm rms) of hemispherical ULE® substrates of EUVL projection optics.
Effect of Low-Energy Ga Ion Implantation on Selective Growth of Gallium Nitride Layer on Silicon Nitride Surfaces Using Metal Organic Chemical Vapor Deposition
Authors: Isiizumi Kazuya , Kikkawa Jun , Nakamura Yoshiaki , Sakai Akira , Yanagisawa Junichi
Published: June 2011

Selective formation of GaN on a silicon nitride (SiN
x
) surface by metal organic chemical vapor deposition (MOCVD) was investigated. Using a partly Ga+-implanted SiN
x
surface, selective growth of materials was confirmed in the Ga+-implanted region of the SiN
x
surface without using any masks during the MOCVD process. The surface roughness induced by Ga+ implantation was found to be negligible from atomic force microscopy measurement results. From the confocal microscopy image analysis, X-ray diffraction measurement, and transmission electron microscopy observation results, it was found that the deposited material consists of polycrystalline hexagonal-GaN grains with a size of about 2 µm. A growth mechanism of GaN on the Ga+-implanted SiN
x
surface is proposed.
Dynamics of Radical Cation of Poly(styrene acrylate)-Based Chemically Amplified Resist for Extreme Ultraviolet and Electron Beam Lithography
Authors: Tajima Yasuharu , Okamoto Kazumasa , Kozawa Takahiro , Tagawa Seiichi , Fujiyoshi Ryoko , Sumiyoshi Takashi
Published: June 2011

The dependence of the degree of copolymerization on the dynamics of radical cations of resist polymers was studied. The dynamics of radical cations was investigated in a chemically amplified resist polymer system. In this study, poly(styrene-ran-methyl methacrylate) [P(S–MMA)] was used as the base polymer of the resist model compound. It is suggested that radical cations of MMA are predominantly decomposed to be deprotonated immediately before the hole transfer to the styrene unit in P(S–MMA) at a lower styrene mole fraction (<50%). However, the acid yield of the P(S–MMA) decreases to that of PS with increasing styrene mole fraction (>70%). It is thus suggested that the hole transfer from the MMA to the multiple styrene units (n > 3) occurs in P(S–MMA).
Thermal Dissipation of High-Brightness Light Emitting Diode by Using Multiwalled Carbon Nanotube/SiC Composites
Authors: Li Bing-Jing , Chang Chih-Hsiang , Su Yun-Kuin , Gan Kwang-Jow
Published: June 2011

To improve the thermal conductance of epoxy used in the high-brightness light emitting diode (HB-LED) package, varied types of fillers were investigated. These fillers included non-functionalized multiwalled carbon nanotubes (MWCNTs), functionalized MWCNTs, micro-SiC particles and the composite of functionalized MWCNTs and micro-SiC particles. Forward voltages at test conditions, junction temperatures, luminous fluxes and operation current–forward voltage (I–V) relation of HB-LEDs were measured or determined for varied combination and contents of fillers in the epoxy. The experimental results showed the epoxy with the composite of 30 wt % of SiC and 5 wt % of MWCNTs had the best thermal properties. Comparing to commercial epoxy, under the operation of injection current of 350 mA, the MWCNT/SiC/epoxy could decrease junction temperature from 123 to 93 °C and thermal resistance from 81 to 65 °C/W.
Effect of TiO2Nanoparticle Modification on Ultraviolet Photodetection Properties of Al-Doped ZnO Nanowire Network
Authors: Kim Kang-Pil , Chang Daeic , Lim Sang Kyoo , Lee Soo-Keun , Lyu Hong-Kun , Hwang Dae-Kue
Published: June 2011

This study was conducted in order to observe the changes in the ultraviolet (UV) photodetection characteristic when TiO2nanoparticles are modified on the surface of an aluminum-doped zinc oxide (AZO) nanowire in an AZO nanowire network with enhanced conductivity. According to the experiment results, the UV photosensitivity under a bias of 5 V was 52-fold in a bare AZO network, and it increased to 147-fold in the case when TiO2nanoparticles were modified. The UV reset time decreased from 9 to 5 s. The AZO nanowire onto which TiO2nanoparticles were adsorbed showed an approximately 2-fold faster response time and an approximately 3-fold higher UV photosensitivity than the existing bare AZO nanowire. The faster UV photoresponse time of the AZO nanowire network with adsorbed TiO2nanoparticles is because the adsorbed TiO2nanoparticles serve as recombination sites for electrons excited by UV illumination. In addition, with enhanced UV photosensitivity, adsorbed TiO2nanoparticles serve as electron donation sites that provide additional electrons to the AZO nanowire when UV light is turned on.
Dye-Sensitized Solar Cell with Photoanode Made with Polystyrene-Ball-Embedded TiO2Pastes
Authors: Hsu Yu-Ching , Wu Tony Chang Chi , Cheng I-Chun , Chen Jian-Zhang , Yang Mu-Rong
Published: June 2011

We report the effect of varying the concentration of polystyrene (PS) balls embedded in TiO2paste during the fabrication of TiO2photoanodes on the performance of dye-sensitized solar cells (DSSCs). We fabricated porous photoanodes using TiO2pastes mixed with various concentrations of PS balls in aqueous solution. During the TiO2sintering processes, the PS evaporated, leaving behind large cavities (>1 µm) in the photoanodes. These cavities enhance the scattering of light, leading to improved absorption of light by N3 dyes. DSSC efficiency increases with the increase in PS ball concentration during TiO2fabrication. As with classical devices, TiCl4treatment of TiO2and the use of a compact TiO2layer both improve the cell efficiency of DSSC devices with our large-cavity TiO2photoanodes.
Physical Model for High-to-Low Resistive Switching of Gold Nanogap Junction
Authors: Naitoh Yasuhisa , Suga Hiroshi , Horikawa Masayo
Published: June 2011

Electric properties of resistive switching in gold nanogap junction were investigated to discuss a physical model of high-to-low resistive switching of the junction. The threshold voltages during the switching are in proportion to logarithm of resistances immediately before the switching. This result indicates that the threshold voltages are depended on electric field, the critical value of which is estimated at about 1.8 V/nm. This implies that the high-to-low resistive switching can be explained by field-induced-migration model.
Threshold Current Density of the Resistance Switching in Pt Nanogap Electrode
Authors: Suga Hiroshi , Sumiya Touru , Horikawa Masayo , Kumaragurubaran Somu , Shimizu Tetsuo , Naitoh Yasuhisa
Published: June 2011

The current density of the resistance switching of the Pt nanogap electrode was investigated to determine the nature of the electromigration responsible for the switching. The current density that is estimated from the measured current and emission area calculated using the tunneling equation is 12.1×1011 A/m2, and is nearly twice that of the Au nanogap electrode. This material dependence of the current density is related to the activation energy for electromigration, which implies that the resistance switching of nanogap electrodes is caused by electromigration.
Simplified Model of the Effect of Source/Drain Doping Gradient on Capacitance and Resistance in a Double-Gate Metal–Oxide–Semiconductor Field-Effect Transistor
Authors: Moon Dae-hyun , Song Jae-Joon , Kim Ohyun
Published: June 2011

Simplified models of capacitance and resistance in the external region are presented and the mobility enhancement effect is verified for extremely scaled and undoped double-gate metal–oxide–semiconductor field-effect transistors (MOSFETs) with the raised source/drain and self-aligned silicide structure and different source/drain doping gradients. The accuracy and universality of these models were confirmed using a two-dimensional simulator. Results indicated that a 3 nm increment of the source/drain lateral doping straggle can reduce the intrinsic delay by about 30% and the leakage current by about 95%.
Nanostructured ZnO/Conjugated Polymer for p–n Heterojunctions
Authors: Yang Chun Mei , Hon Min Hsiung , Leu Ing Chi
Published: June 2011

High-density vertically aligned ZnO nanotubes (NTs) were prepared by etching ZnO nanorods (NRs) in aqueous solution, which were grown from ZnO sol–gel-derived seeds coated on transparent conductive glass substrate. We investigated the preparation of nanostructured oxide/conjugated polymer hybrid solar cells, where the regioregular poly(3-hexylthiophene) was infiltrated into transparent ZnO nanorod or nanotube films. The hybrid can take advantage of the high electron mobility attainable in oxide semiconductors and can be fabricated using low temperature aqueous solution growth techniques. Additionally, the morphology of the hybrid can be controlled in a systematic way through growth of the nanostructured ZnO to obtain a large amount of surface area. Because of the increased specific surface area, the power efficiency of cells based on ZnO NTs enhances twice as that of ZnO NRs. In other words, the nanotubes can offer a highly ordered material architecture with efficient charge generation and collection of electron in hybrid solar cells. A relation between efficiency and surface area is demonstrated.
Distinctive Feature of Ripening During Growth Interruption of InGaAs Quantum Dot Epitaxy Using Bi as a Surfactant
Authors: Okamoto Hiroshi , Tawara Takehiko , Tateno Kouta , Gotoh Hideki , Kamada Hidehiko , Sogawa Tetsuomi
Published: June 2011

“Ripening” is a process in which some particles grow at the expense of others. In this study, a distinctive feature of ripening was observed for InGaAs quantum dots (QDs), which were grown using Bi as a surfactant. The uniformity of QDs was much improved during the growth interruption after QD growth by ripening. Another remarkable feature is that the QD size converged to a specific range after the ripening. This fact means that a partially stable condition of QD size appeared as a result of the QD growth sequence, which consists of Bi surfactant growth and growth interruption. It is also pointed out that proper control of the atmosphere during growth interruption is important for QD epitaxy with Bi surfactant.
Accurate Electronic Structures of Eu-Doped SiAlON Green Phosphor with a Semilocal Exchange–Correlation Potential
Authors: Yoo Dong Su , Ryu Jeong Ho , Lee Sung-Ho , Cho Hyun , Chung Yong-Chae
Published: June 2011

The crystal structure, electronic structure, and photoluminescence properties of Eu
x
Si6-z
Al
z
O
z
N8-z
(x = 0.01754, z = 0.25) green phosphor were calculated by modified version of the exchange potential proposed by Becke and Johnson [J. Chem. Phys. 124 (2006) 221101]. An interstitially doped Eu atom was found in the atomic channel parallel to the [0001] axis. The additional states originated from the hybridization of Eu 4f and Eu 5d with Si 3p and N 2p. The luminescence properties were analyzed using a quantitative calculation of the energy gap and the wavelength. The calculated emission peak wavelength of Eu from the energy gap between Eu 5d and Eu 4f was 552 nm. Conventional local or semi local density functionals always underestimate the band gap for wide gap semiconductor. In contrast, the calculated results using the semi local potential well agreed with experiment.
Combinatorial Investigation of ZrO2-Based Dielectric Materials for Dynamic Random-Access Memory Capacitors
Authors: Kiyota Yuji , Itaka Kenji , Iwashita Yuta , Adachi Tetsuya , Chikyow Toyohiro , Ogura Atsushi
Published: June 2011

We investigated zirconia (ZrO2)-based material libraries in search of new dielectric materials for dynamic random-access memory (DRAM) by combinatorial-pulsed laser deposition (combi-PLD). We found that the substitution of yttrium (Y) to Zr sites in the ZrO2 system suppressed the leakage current effectively. The metal–insulator–metal (MIM) capacitor property of this system showed a leakage current density of less than 5×10-7 A/cm2 and the dielectric constant was 20. Moreover, the addition of titanium (Ti) or tantalum (Ta) to this system caused the dielectric constant to increase to ∼25 within the allowed leakage level of 5×10-7 A/cm2. Therefore, Zr–Y–Ti–O and Zr–Y–Ta–O systems have good potentials for use as new materials with high dielectric constants of DRAM capacitors instead of silicon dioxides (SiO2).
Production of Double-Layered Metal Nanocups for Artificial Nanospace of Biomolecular Reaction
Authors: Kim Hyonchol , Hayashi Masahito , Terazono Hideyuki , Takei Hiroyuki , Yasuda Kenji
Published: June 2011

Nanocups (NCs), sub-micrometer semispherical bowls consisting of two different nanometer-thick metals on inner and outer layers, have been fabricated to mimic a localized nano-scale biochemical reaction environment for reactive biomolecules. Homogeneous polystyrene beads were used as a cast of the NCs, placed on a Si substrate, dried, and processed by oxygen plasma etching until the desired diameters and gaps among neighboring bead casts. For the fabrication of Au/Ni double-layered NCs, Au and Ni were sequentially deposited on upper halves of the bead surfaces by thermal evaporation with nanometer-order thickness control. The polystyrene casts were removed completely by UV–ozone oxidization reaction, and Au/Ni double-layered NCs were fabricated on a Si substrate. To orient the holes of the fabricated NCs to top for the substrate, poly(dimethylsiloxane) (PDMS) sol was dropped on the NCs placed on the Si substrate, hardened, and peeled off from the substrate, and then the NCs were placed on the PDMS surface with those holes turned-up. To examine the selective interaction of biomolecules on the inner layer of NCs as the artificial nanospace for biomolecular reactions, a thiolated target DNA was immobilized onto the inner layer of a Au/Ni NC as a model. The target DNA was labeled through hybridization reaction using small Au nanoparticles (NPs) on which a complementary probe DNA was immobilized. Both the surface-specific immobilization of the target DNA on the Au layer of the NC and the specific hybridization in NC nanospaces were confirmed by direct observations after those reactions using field emission scanning electron microscopy (FE-SEM), indicating that the inside of the fabricated NCs can be used as the artificial nanospace for studying localized biomolecular reactions.
Signal Processing Using Karhunen–Loève Expansion for Wafer Focus Measurement in Lithography
Authors: Oishi Satoru , Ina Hideki , Miyashita Tomoyuki
Published: June 2011

We propose a new signal processing method using Karhunen–Loève (KL) expansion for wafer focus measurement in lithography. With the improvement in the critical dimension (CD) accuracy, more high accuracy of wafer focus measurement becomes to be necessary. Recently, it is said that focus accuracy should be required within several ten nanometers. The accuracy of the focus measurement of the actual process wafer does not meet the requirement values due to the complexity of its structure. The objective of this study is the improvement of the focus accuracy for the actual process wafers. Our proposing focus signal processing has two steps. The first step is a supervised learning step in which main component signal waveforms (basis functions) are obtained by using KL expansion from many focus signals whose center positions are known in advance. The second step is a center position detecting step in which an input signal is approximated by using the basis functions obtained in the learning step and the center position of the signal is detected. From a comparison between the conventional signal processing and the proposing signal processing, we obtained the following result to simulated signal. Focus accuracy was rapidly improved (97%) when three basis functions were used for the approximation. By using this technology, the focus detection system can be achieved with a high accuracy and robust against various process wafers.
Fluorescent Microscopy Proving Resin Adhesion to a Fluorinated Mold Surface Suppressed by Pentafluoropropane in Step-and-Repeat Ultraviolet Nanoimprinting
Authors: Kobayashi Kei , Kubo Shoichi , Hiroshima Hiroshi , Matsui Shinji , Nakagawa Masaru
Published: June 2011

Resin adsorption on fluorinated silica mold surfaces during step-and-repeat ultraviolet nanoimprinting was studied by fluorescent microscopy using a fluorescent UV-curable resist. The fluorescence intensity indicating resin adsorption to the mold surfaces in step-and-repeat UV nanoimprinting under air atmosphere was significantly higher than that under condensable gas pentafluoropropane (PFP) atmosphere. The larger resin adsorption in air was attributable to sticking uncured resin around trapped air bubbles preventing the UV-curable resist from causing acrylate radical photopolymerization and to the small amount of resin components adhering to the mold surface. The entire adsorption of resin components, not only a fluorescent dye doped in a UV-curable resin, was confirmed by high-sensitivity UV–visible absorption spectroscopy and atomic force microscopy in a frictional mode. PFP suppressed obviously stuck uncured resin and entirely adhered resin components to the fluorinated mold surface. The entire adsorption of resin components was compared among three kinds of fluorinated mold surface treated with commercially available antisticking reagents, FAS13 (tridecafluoro-1,1,2,2-tetrahydro-octyltrimethoxysilane), OPTOOL DSX, and OPTOOL AES4-E. It was proved by the fluorescent microscopy that the fluorinated mold surface prepared by chemical vapor surface modification with FAS13 showed the best antisticking property among the fluorinated mold surfaces, because the entire adsorption of resin components was hardly affected by the number of cycles of step-and-repeat UV nanoimprinting and by the positions in the mold surface.
Degradation of Perfluorotrichlorosilane Antisticking Layers: The Impact on Mold Cleaning, Ultraviolet-Nanoimprinting, and Bonded Ultraviolet-Nanoimprint Molds
Authors: Kirchner Robert , Teng Lichao , Lu Bo , Adolphi Barbara , Fischer Wolf-Joachim
Published: June 2011

A reduction of the adhesion between imprint resist and mold is crucial for defect free imprints and is commonly achieved by silane based antisticking layers. Highly stable antisticking layers are required for high throughputs and long imprint mold lifetimes. Hybrid nanoimprint molds avoid the imprint inherent residual polymer layer in UV-assisted nanoimprinting. Such hybrid molds have chemically heterogeneous surfaces of silica and, e.g., chromium oxide regions. The chemical stability of vapor-coated 1H,1H,2H,2H-perfluorodecyltrichlorosilane antisticking layers against acetone, acidic piranha, reactive ion etching and UV-assisted nanoimprinting was investigated. To evaluate the behavior of hybrid mold surfaces, flat silica and antireflective chromium-oxynitride surfaces were used. The antisticking layer on both surfaces was highly chemical resistant against acetone. A continuous antisticking layer degradation with a surface free energy increase of 0.9 mN/m per 10 min piranha treatment and 1.2 mN/m per 10 subsequent UV-assisted imprints was found for silica surfaces. On the chromium surfaces, the antisticking layer quality was much lower than on fused silica and degraded much faster. The surface free energy of silane coated chromium surfaces was increased by 2.3 mN/m after 10 imprints and the antisticking layer was completely degraded after a single 10 min piranha cleaning step. The lower antisticking layer quality on antireflective chromium was attributed to the surface itself. Additionally, the high chemical resistance of the vapor coated silane was used to successfully protect the adhesive joints of cost-efficient, adhesively bonded nanoimprint molds from being degraded by acidic piranha during mold cleaning. This can significantly increase the life-time of such bonded molds.
Hydrophilicity of Surfactant-Added Poly(dimethylsiloxane) and Its Applications
Authors: Kim Hui Tak , Kim Jeong Koo , Jeong Ok Chan
Published: June 2011

This paper discusses the hydrophilicity of surfactant-added poly(dimethylsiloxane) (PDMS) and its applications. The contact angle of water droplets was measured in order to study the short- and long-term stability of the hydrophilicity of PDMS combined with various concentrations of the surfactant Silwet L-77 as a wetting agent. In the short-term, the contact angle was measured every 20 s for 10 min and decreased dramatically with time as the concentration of surfactant was increased from 0 to 1%. In water droplets observed for 800 h, the hydrophobic recovery of the surfactant-added PDMS was very weak and minor. As applications, a micropump and pneumatic actuators were fabricated using only surfactant-added PDMS. The basic properties of surfactant-added PDMS, such as the contact angle of the water head in the microchannel and Young's modulus, were measured and discussed.
Development of a Wireless Love Wave Biosensor Platform for Multi-functional Detection
Authors: Song Taehyeon , Song Seung Yeon , Yoon Hyun C. , Lee Keekeun
Published: June 2011

A Love wave-based biosensor with a 440 MHz operating frequency was developed for simultaneous detection of two different concentrations of anti-dinitrophenyl-keyhole limpet hemocyanin (Anti-DNP-KLH) rabbit immunoglobulin G (IgG) in a single sensor. The sensor was composed of surface acoustic wave (SAW) reflective delay lines built from interdigital transducer (IDT) and several reflectors, a poly(methyl methacrylate) (PMMA) waveguide layer, and two sensitive films. To extract optimal device parameters, coupling of mode (COM) modeling was carried. According to the device parameters determined, the Love wave biosensor was fabricated and then wirelessly characterized by a network analyzer. Binding of anti-DNP IgG to DNP induced a change in the time positions of the original reflection peaks mainly due to the mass loading effect. The measured time positions were matched well with the predicted values from COM modeling. The sensitivities evaluated from the first and second sensitive films were 167.9 and 44.8 deg·µg-1·ml-1, respectively.
Tunable Microchip Design for Solvent-Based Bonding of Poly(methyl methacrylate) Substrates by Capillary Force Inequality
Authors: Min Junggi , Yun Hoyoung , Park Tae Gyu , Kang Yeon June , Han Dong-Chul
Published: June 2011

Among various bonding methods for polymeric microfluidic chips, solvent-based bonding techniques present a relatively high bonding strength and a simple bonding process. However, there are still several considerations for bonding success: the bonding time to achieve a high throughput and a low temperature, and the clogging issue from the solvent overflowing into microfluidic channels. In this work, a novel design method and fabrication of microfluidic chips with solvent-based bonding without microchannel clogging are demonstrated. These microfluidic chips could be bonded in just 10 s at room temperature without additional steps or materials. By using the capillary force inequality caused by height differences between the inside and outside of the microchannel, we could control the solvent movement for bonding two chips. In conclusion, the tunable microchips obtained by the proposed solvent bonding technology might make mass production possible.
Programmable Dielectrophoretic Chip for Cell Manipulations
Authors: Chuang Cheng-Hsin , Huang Yao-Wei , Wu Yao-Tung , Wu Ting-Feng
Published: June 2011

A dielectrophoretic (DEP) chip has been designed and fabricated for programmable manipulations of live cells, including the focusing and trapping of cells, and individual release of the target cells. The DEP chip consists of three layers of electrodes: an indium tin oxide (ITO) top electrode, middle electrodes with a focusing part and a trapping part on an SU-8 surface, and bottom releasing electrodes. In order to demonstrate the capability of multistep manipulations within a single chip, a PC-based program and an interface circuit were integrated with the DEP chip for the manipulation of human bladder cells (TSGH-8301). According to the simulation and experimental results, cells can be aligned along the gap of the focusing electrode and trapped into the microcavity by means of the negative DEP force between top and middle electrodes. Furthermore, the trapped cells can be released from the microcavity to the flow chamber by negative DEP force between the top and bottom electrodes. Consequently, the DEP chip provides an excellent platform technology for lab-on-a-chip (LOC) or micro-total-analysis-system (Micro TAS).
Three-Dimensional Molding Based on Microstereolithography Using Beta-Tricalcium Phosphate Slurry for the Production of Bioceramic Scaffolds
Authors: Torii Takashi , Inada Makoto , Maruo Shoji
Published: June 2011

We report on a three-dimensional (3D) molding technique of fabricating bioceramic scaffolds. In this method, ceramic slurry is cast into a 3D polymer master mold, which is fabricated via microstereolithography, by a centrifugal casting method. The polymer master mold is thermally decomposed, so that a complex 3D bioceramic scaffold can be produced. In experiments, the decomposition process of the polymer model was optimized by the master decomposition curve theory to reduce harmful cracks in a green body. As a result, we could produce not only precise lattice models but also a sophisticated porous scaffold using beta-tricalcium phosphate (β-TCP) slurry. This bioceramic 3D molding technique based on microstereolithography will be useful for tailor-made tissue engineering and regeneration medicine.
Doubled Optical Path Length for Photonic Bandgap Fiber Gas Cell Using Micromirror
Authors: Li Xuefeng , Liang Jinxing , Oigawa Hiroshi , Ueda Toshitsugu
Published: June 2011

In this paper, we presented the double optical path length of a photonic bandgap fiber (PBGF) gas cell. The gas sensor sensitivity can be improved by a two fold lengthening of the optical length without changing the gas fluid. Furthermore, a high-reflection micromirror was included in the proposed double optical path length gas cell. A Cr/Au sputtering process was applied to fabricate the vertical micromirror using a single-mode fiber (SMF). A measurement system for low gas concentrations based on the micromirror has been implemented, and sensitivity was improved without increasing the response time.
Efficient and Deterministic Parallel Placement for FPGAs
Authors: Ludwin Adrian , Betz Vaughn
Published: June 2011

We describe a parallel simulated annealing algorithm for FPGA placement. The algorithm proposes and evaluates multiple moves in parallel, and has been incorporated into Altera’s Quartus II CAD system. Across a set of 18 industrial benchmark circuits, we achieve geometric average speedups during the quench of 2.7x and 4.0x on four and eight processors, respectively, with individual circuits achieving speedups of up to 3.6x and 5.9x. Over the course of the entire anneal, we achieve speedups of up to 2.8x and 3.7x, with geometric average speedups of 2.1x and 2.4x.

Our algorithm is the first parallel placer to optimize for criteria other than wirelength, such as critical path length, and is one of the few deterministic parallel placement algorithms. We discuss the challenges involved in combining these two features and the new techniques we used to overcome them. We also quantify the impact of maintaining determinism on eight cores, and find that while it reduces performance by approximately 15% relative to an ideal speedup of 8.0x, hardware limitations are a larger factor and reduce performance by 30--40%. We then suggest possible enhancements to allow our approach to scale to 16 cores and beyond.
Design and Implementation of a Throughput-Optimized GPU Floorplanning Algorithm
Authors: Han Yiding , Chakraborty Koushik , Roy Sanghamitra , Kuntamukkala Vilasita
Published: June 2011

In this article, we propose a novel floorplanning algorithm for GPUs. Floorplanning is an inherently sequential algorithm, far from the typical programs suitable for Single-Instruction Multiple-Thread (SIMT)-style concurrency in a GPU. We propose a fundamentally different approach of exploring the floorplan solution space, where we evaluate concurrent moves on a given floorplan. We illustrate several performance optimization techniques for this algorithm in GPUs. To improve the solution quality, we present a comprehensive exploration of the design space, including various techniques to adapt the annealing approach in a GPU. Compared to the sequential algorithm, our techniques achieve 6--188X speedup for a range of MCNC and GSRC benchmarks, while delivering comparable or better solution quality.
GPU-Based Parallelization for Fast Circuit Optimization
Authors: Liu Yifang , Hu Jiang
Published: June 2011

The progress of GPU (Graphics Processing Unit) technology opens a new avenue for boosting computing power. This work is an attempt to exploit the GPU for accelerating VLSI circuit optimization. We propose GPU-based parallel computing techniques and apply them on simultaneous gate sizing and threshold voltage assignment, which is a popular method for VLSI performance and power optimization. These techniques include efficient task scheduling and memory organization, all of which are aimed to fully utilize the advantages of GPUs. Compared to conventional sequential computation, our techniques can provide up to 56× (39× on average) speedup without any sacrifice on solution quality.
Accelerating UNISIM-Based Cycle-Level Microarchitectural Simulations on Multicore Platforms
Authors: Liao Xiongfei , Srikanthan Thambipillai
Published: June 2011

UNISIM has been shown to ease the development of simulators for multi-/many-core systems. However, UNISIM cycle-level simulations of large-scale multiprocessor systems could be very time consuming. In this article, we propose a systematic framework for accelerating UNISIM cycle-level simulations on multicore platforms. The proposed framework relies on exploiting the fine-grained parallelism within the simulated cycles using POSIX threads. A multithreaded simulation engine has been devised from the single-threaded UNISIM SystemC engine to facilitate the exploitation of inherent parallelism. An adaptive technique that manages the overall computation workload by adjusting the number of threads employed at any given time is proposed. In addition, we have introduced a technique to balance the workloads of multithreaded executions. This load balancing involves the distributions of SystemC objects among threads. A graph-partitioning-based technique has been introduced to automate such distributions. Finally, two strategies are proposed for realizing nonautomated and fully automated adaptive multithreaded simulations, respectively. Our investigations show that notable acceleration can be achieved by deploying the proposed framework. In particular, we show that simulations on an 8-core multicore platform can provide for close to 6X speedups when simulating many-core systems with large number of cores.
A New Algorithm for VHDL Parallel Simulation
Authors: García-Dopico Antonio , Pérez Antonio , Rodríguez Santiago , García María Isabel
Published: June 2011

This article proposes a new algorithm for parallel synchronous simulation of VHDL designs to be executed on desktop computers. Besides executing VHDL processes in parallel, the algorithm focuses on parallelizing the simulation kernel with special emphasis on signal grouping while maintaining language semantics. Synchronous approaches are the most suitable for shared memory multiprocessor (SMP) desktop computers but may be difficult to parallelize because of the low activity detected in most of the designs. The degree of parallelism is increased in this approach by performing an exhaustive VHDL signal dependencies analysis and avoiding any sequential phase in the simulator. VHDL semantics impose a synchronization barrier after each phase, that is, the process and the kernel simulation phase, as the language definition does not allow simultaneous execution of kernel and processes. These barriers have been relaxed in order to increase the level of parallelism and obtain better performance. Another aspect the new algorithm takes into account is to improve load balancing and locality of references, both critical issues in synchronous simulators, by introducing a new load balancing algorithm that exploits the cyclic characteristics of circuit simulators. These developments make the algorithm suitable for commodity hardware, that is, SMP that are currently used as desktop personal computers.
Locality-Driven Parallel Static Analysis for Power Delivery Networks
Authors: Zeng Zhiyu , Feng Zhuo , Li Peng , Sarin Vivek
Published: June 2011

Large VLSI on-chip Power Delivery Networks (PDNs) are challenging to analyze due to the sheer network complexity. In this article, a novel parallel partitioning-based PDN analysis approach is presented. We use the boundary circuit responses of each partition to divide the full grid simulation problem into a set of independent subgrid simulation problems. Instead of solving exact boundary circuit responses, a more efficient scheme is proposed to provide near-exact approximation to the boundary circuit responses by exploiting the spatial locality of the flip-chip-type power grids. This scheme is also used in a block-based iterative error reduction process to achieve fast convergence. Detailed computational cost analysis and performance modeling is carried out to determine the optimal (or near-optimal) number of partitions for parallel implementation. Through the analysis of several large power grids, the proposed approach is shown to have excellent parallel efficiency, fast convergence, and favorable scalability. Our approach can solve a 16-million-node power grid in 18 seconds on an IBM p5-575 processing node with 16 Power5+ processors, which is 18.8X faster than a state-of-the-art direct solver.
Gate-Level Simulation with GPU Computing
Authors: Chatterjee Debapriya , Deorio Andrew , Bertacco Valeria
Published: June 2011

Functional verification of modern digital designs is a crucial, time-consuming task impacting not only the correctness of the final product, but also its time to market. At the heart of most of today’s verification efforts is logic simulation, used heavily to verify the functional correctness of a design for a broad range of abstraction levels. In mainstream industry verification methodologies, typical setups coordinate the validation effort of a complex digital system by distributing logic simulation tasks among vast server farms for months at a time. Yet, the performance of logic simulation is not sufficient to satisfy the demand, leading to incomplete validation processes, escaped functional bugs, and continuous pressure on the EDA industry to develop faster simulation solutions.

In this work we propose GCS, a solution to boost the performance of logic simulation, gate-level simulation in particular, by more than a factor of 10 using recent hardware advances in Graphic Processing Unit (GPU) technology. Noting the vast available parallelism in the hardware of modern GPUs and the inherently parallel structures of gate-level netlists, we propose novel algorithms for the efficient mapping of complex designs to parallel hardware.

Our novel simulation architecture maximizes the utilization of concurrent hardware resources while minimizing expensive communication overhead. The experimental results show that our GPU-based simulator is capable of handling the validation of industrial-size designs while delivering more than an order-of-magnitude performance improvements on average, over the fastest multithreaded simulators commercially available.
Chassis
Authors: Ain Antara , Pal Debjit , Dasgupta Pallab , Mukhopadhyay Siddhartha , Mukhopadhyay Rajdeep , Gough John
Published: June 2011

Power Management Units (PMUs) are large integrated circuits consisting of many predesigned mixed-signal components. PMU integration poses a serious verification problem considering the size of the integrated circuit and the complexity of analog simulation. In this article we present an approach for automatic generation of behavioral models for PMU components from top-down skeleton models, fitted with parameter values estimated by bottom-up parameter extraction algorithms. It is shown that replacing PMU components with these autogenerated hybrid automata-based abstract behavioral models enables significant simulation speedup (> 20X on our industrial test cases) and helps in early detection of integration errors. The article also justifies the level of accuracy in our models with respect to the goal of verifying integrated PMUs. The approach presented in this work is implemented in the form of a tool suite called Chassis.
A Metric for Quantifying Similarity between Timing Constraint Sets in Real-Time Systems
Authors: Yu Yue , Ren Shangping , Hu Xiaobo Sharon
Published: June 2011

Real-time systems are systems in which their timing behaviors must satisfy a specified set of timing constraints and they often operate in a real-world environment with scarce resources. As a result, the actual runtime performance of these systems may deviate from the design, either inevitably due to unpredictable factors or by intention in order to improve system’s other Quality-of-Service (QoS) properties. In this article, we first introduce a new metric,
timing constraint set similarity
, to quantify the resemblance between two different timing constraint sets. Because directly calculating the exact value of the metric involves calculating the size of a polytope which is a #
P
-hard problem, we instead introduce an efficient method for estimating its bound. We further illustrate how this metric can be exploited for improving system predictability and for evaluating trade-offs between timing constraint compromises and the system’s other QoS property gains.
Development of a New Tool for 3D Modeling for Regenerative Medicine
Authors: Mattoli Filippo , Tiribuzi Roberto , D'Angelo Francesco , di Girolamo Ilaria , Quattrocelli Mattia , Montesano Simona , Crispoltoni Lucia , Oikonomou Vasileios , Cusella De Angelis Maria Gabriella , Marconi Peggy , Orlacchio Antonio , Sampaolesi Maurilio , Martino Sabata , Orlacchio Aldo
Published: June 2011

The effectiveness of therapeutic treatment based on regenerative medicine for degenerative diseases (i.e., neurodegenerative or cardiac diseases) requires tools allowing the visualization and analysis of the three-dimensional (3D) distribution of target drugs within the tissue. Here, we present a new computational procedure able to overcome the limitations of visual analysis emerging by the examination of a molecular signal within images of serial tissue/organ sections by using the conventional techniques. Together with the 3D anatomical reconstitution of the tissue/organ, our framework allows the detection of signals of different origins (e.g., marked generic molecules, colorimetric, or fluorimetric substrates for enzymes; microRNA; recombinant protein). Remarkably, the application does not require the employment of specific tracking reagents for the imaging analysis. We report two different representative applications: the first shows the reconstruction of a 3D model of mouse brain with the analysis of the distribution of theβ-Galactosidase, the second shows the reconstruction of a 3D mouse heart with the measurement of the cardiac volume.
A Characterization of Planar Mixed Automorphic Forms
Authors: Ghanmi Allal
Published: June 2011

We characterize the functional space of the planar mixed automorphic forms with respect to an equivariant pair and given lattice as the image of the Landau automorphic forms (involving special multiplier)
by an appropriate isomorphic transform.
New‐Type Solutions of the Modified Fischer‐Kolmogorov Equation
Authors: Drábek P.
Published: June 2011

We prove the existence of new‐type solutions of the modified
Fischer‐Kolmogorov equation with slow/fast diffusion and with possibly nonsmooth double‐well potential. We show that a certain relation
between the rate of the diffusion and the smoothness of the potential may originate new type solutions which do not occur in the classical Fischer‐Kolmogorov equation. The main focus of this paper is to show the sensitivity of the mathematical modelling with respect to the chosen form of the diffusion term and the shape of the double‐well potential.
Towards a Brain-Sensitive Intelligent Tutoring System: Detecting Emotions from Brainwaves
Authors: Heraz Alicia , Frasson Claude
Published: June 2011

This paper proposes and evaluates a multiagents system called NORA that predicts emotional attributes from learners' brainwaves within an intelligent tutoring system. The measurements from the electrical brain activity of the learner are combined with information about the learner's emotional attributes. Electroencephalogram was used to measure brainwaves and self-reports to measure the three emotional dimensions: pleasure, arousal, and dominance, the eight emotions occurring during learning: anger, boredom, confusion, contempt curious, disgust, eureka, and frustration, and the emotional valence positive for learning and negative for learning. The system is evaluated on natural data, and it achieves an accuracy of over 63%, significantly outperforming classification using the individual modalities and several other combination schemes.
Totally Umbilical Proper Slant and Hemislant Submanifolds of an LP‐Cosymplectic Manifold
Authors: Uddin Siraj , Khan Meraj Ali , Singh Khushwant
Published: June 2011

In the present note, we study slant and hemislant submanifolds of an LP‐cosymplectic manifold which are totally umbilical. We prove that every totally umbilical proper slant submanifold M of an LP‐cosymplectic manifold is either totally geodesic or if M is not totally geodesic in then we derive a formula for slant angle of M. Also, we obtain the integrability conditions of the distributions of a hemi‐slant submanifold, and then we give a result on its classification.