bluuebunny/crossref_metadata_2025 huggingface dataset:
Cannabis: What Makes University Students More or Less Likely to Use It?
Authors: O'Callaghan Frances V. , Joyce Jessica
Published: August 2010

University students' motivations for using or not using cannabis were investigated. Students (n = 189) aged 17 to 29 years completed a survey to assess their intention to use cannabis and their beliefs about (a) advantages and disadvantages of using cannabis; (b) their perceptions of what significant others think they should do in relation to cannabis use; and (c) factors that might encourage them to use or not use cannabis. Two weeks later, they completed a follow‐up survey asking about their actual behavior over the previous 2 weeks. Compared to non‐users, users believed more strongly that cannabis would help them fit in with their friends, feel relaxed, forget their worries, and enjoy themselves. They also believed that their close friends, partner/spouse, siblings, and workmates would approve of their using cannabis. Users believed that certain factors (e.g., force of habit, wanting to relax, feeling stressed, being around other people using cannabis) would encourage them to use, while non‐users rated work and study as strong reasons for not using cannabis. Beliefs that are relevant to users and non‐users in education campaigns can be targeted to reduce the negative consequences of use in tertiary settings.
Non‐intrusive monitoring of atmospheric CO2 in analogue models of terrestrial carbon cycle
Authors: Lukac Martin , Milcu Alexandru , Wildman Dennis , Anderson Rob , Sloan Tom , Ineson Phil
Published: August 2010

1. Closed ecological systems (CES) are small man‐made ecosystems which do not have any material exchange with the surrounding environment. Recent ecological and technological advances enable successful establishment and maintenance of CES, making them a suitable tool for detecting and measuring subtle feedbacks and mechanisms.

2. As a part of an analogue (physical) C cycle modelling experiment, we developed a non‐intrusive methodology to control the internal environment and to monitor atmospheric CO2 concentration inside 16 replicated CES. Whilst maintaining an air‐tight seal of all CES, this approach allowed for access to the CO2 measuring equipment for periodic re‐calibration and repairs.

3. To ensure reliable cross‐comparison of CO2 observations between individual CES units and to minimize the cost of the system, only one CO2 sampling unit was used. An ADC BioScientific OP‐2 (open‐path) analyser mounted on a swinging arm was passing over a set of 16 measuring cells. Each cell was connected to an individual CES with air continuously circulating between them.

4. Using this setup, we were able to continuously measure several environmental variables and CO2 concentration within each closed system, allowing us to study minute effects of changing temperature on C fluxes within each CES. The CES and the measuring cells showed minimal air leakage during an experimental run lasting, on average, 3 months. The CO2 analyser assembly performed reliably for over 2 years, however an early iteration of the present design proved to be sensitive to positioning errors.

5. We indicate how the methodology can be further improved and suggest possible avenues where future CES based research could be applied.
Nonlinear Dynamic Behavior of Turbocharger Rotor-Bearing Systems With Hydrodynamic Oil Film and Squeeze Film Damper in Series: Prediction and Experiment
Authors: Gjika K. , San Andrés L. , Larue G. D.
Published: August 2010

Current trends for advanced automotive engines focusing on downsizing, better fuel efficiency, and lower emissions have led to several changes in turbocharger bearing system design and technology. Automotive turbochargers run faster and use engine oils with very low viscosity under high oil inlet temperature and low feed pressure. The development of high performing bearing systems, marrying innovation with reliability, is a persistent challenge. This paper shows progress on the nonlinear dynamic behavior modeling of the rotor-radial bearing system (RBS) incorporating two oil films in series: a hydrodynamic one with a squeeze film damper commonly used in turbochargers. The developed fluid bearing code predicts bearing rotational speed (in the case of fully floating design), operating inner and outer bearing film clearances, effective oil viscosity, taking into account its shear effect, and hydrostatic load. A rotordynamics code uses this input to predict the nonlinear lateral dynamic response of the rotor-bearing system. The model predictions are validated with test data acquired on a high speed turbocharger RBS of a 6.0 mm journal diameter running up to 250,000 rpm (maximum speed), 5W30 oil type, 150°C oil inlet temperature, and 4 bar oil feed pressure. The tests are conducted at a rotordynamics technology laboratory using a high performance data acquisition system. Turbochargers with four combinations of inner and outer RBS clearances are tested. Prediction and measured synchronous response and total motion are in good agreement. Both demonstrate the nonlinear character of the RBS behavior, including several subsynchronous frequency components across the operating speed range. The nonlinear predictive model aids the development of high performance and optimized turbocharger RBS with faster development cycle times and increased reliability.
Sources of Error in a Simulation of Rigid Parts on a Vibrating Rigid Plate
Authors: Berard Stephen , Nguyen Binh , Anderson Kurt , Trinkle J. C.
Published: August 2010

We present a simulation study of an important rigid-body contact problem. The system in question is composed of a rigid plate and a single rigid body (or particle). The plate follows a prescribed periodic motion of small amplitude and high frequency, such that the net force applied to the part appears to be from a time-independent, position-dependent velocity field in the plane of the plate. Theoretical results obtained by Vose et al. were found to be in good agreement with simulation results obtained with the Stewart–Trinkle time-stepping method. In addition, simulations were found to agree with the qualitative experimental results of Vose et al. After such verification of the simulation method, additional numerical studies were done that would have been impossible to carry out analytically. Specifically, we were able to demonstrate the convergence of the method with decreasing step size (as predicted theoretically by Stewart). Further analytical and numerical studies will be carried out in the future to develop and select robust simulation methods that best satisfy the speed and accuracy requirements of different applications. With the accuracy of our time-stepper verified for this system, we were able to study the inverse problem of designing new plate motions to generate a desired part motion. This is done through an optimization framework, where a simulation of the part interacting with the plate (including the full dynamics of the system) is performed, and based on the results of the simulation the motion of the plate is modified. The learned (by simulation) plate motion was experimentally run on the device, and without any tuning (of the simulation parameters or device parameters) our learned plate motion produced the desired part motion.
Sliding Modes for the Simulation of Mechanical and Electrical Systems Defined by Differential-Algebraic Equations
Authors: Rao Sachit , Utkin Vadim , Buss Martin
Published: August 2010

We offer a technique, motivated by feedback control and specifically sliding mode control, for the simulation of differential-algebraic equations (DAEs) that describe common engineering systems such as constrained multibody mechanical structures and electric networks. Our algorithm exploits the basic results from sliding mode control theory to establish a simulation environment that then requires only the most primitive of numerical solvers. We circumvent the most important requisite for the conventional simulation of DAEs: the calculation of a set of consistent initial conditions. Our algorithm, which relies on the enforcement and occurrence of sliding mode, will ensure that the algebraic equation is satisfied by the dynamic system even for inconsistent initial conditions and for all time thereafter.
Integration of Flexible Multibody Systems Using Radau IIA Algorithms
Authors: Wang Jielong , Rodriguez Jesus , Keribar Rifat
Published: August 2010

The two-stage and three-stage Radau IIA stiff integrators, belonging to the implicit Runge–Kutta family, are implemented in a computationally efficient manner to solve flexible multibody systems. These problems feature large displacements and finite rotations together with small elastic deformations. The two-stage and three-stage algorithms are modified to integrate the finite element based, second order differential equations of multibody dynamics directly. A new simplified Newton iteration is implemented for the two-stage algorithm to reduce its computational cost. The resulting linear system of equations obtained at each Newton iteration is solved efficiently for both the two-stage and three-stage algorithms. The Jacobian matrix in the simplified Newton iterations is evaluated through numerical differentiation. A compact storage strategy is used to archive the banded, sparse matrices. The error estimation based on the embedded formula and step size selection are discussed in detail. The proposed schemes are validated with the help of different numerical examples. The simulation results are consistent with those of other types of integrators. These examples show that Radau IIA algorithms can solve stiff problems with acceptable speed while guaranteeing stability and accuracy.
Sensitivity Enhancement of Cantilever-Based Sensors Using Feedback Delays
Authors: Bradley Calvin , Daqaq Mohammed F. , Bibo Amin , Jalili Nader
Published: August 2010

This paper entails a novel sensitivity-enhancement mechanism for cantilever-based sensors. The enhancement scheme is based on exciting the sensor at the clamped end using a delayed-feedback signal obtained by measuring the tip deflection of the sensor. The gain and delay of the feedback signal are chosen such that the base excitations set the beam into stable limit-cycle oscillations as a result of a supercritical Hopf bifurcation of the trivial fixed points. The amplitude of these limit-cycles is shown to be ultrasensitive to parameter variations and, hence, can be utilized for the detection of minute changes in the resonant frequency of the sensor. The first part of the manuscript delves into the theoretical understanding of the proposed mechanism and the operation concept. Using the method of multiple scales, an approximate analytical solution for the steady-state limit-cycle amplitude near the stability boundaries is obtained. This solution is then utilized to provide a comprehensive understanding of the effect of small frequency variations on the limit-cycle amplitude and the sensitivity of these limit-cycles to different design parameters. Once a deep theoretical understanding is established, the manuscript provides an experimental study to investigate the proposed concept. Experimental results demonstrate orders of magnitude sensitivity enhancement over the traditional frequency-shift method.
On Fractional Dynamics on the Extended Phase Space
Authors: Baleanu Dumitru , Muslih Sami I. , Rabei Eqab M. , Golmankhaneh Alireza K. , Golmankhaneh Ali K.
Published: August 2010

Fractional calculus should be applied to various dynamical systems in order to be validated in practice. On this line of taught, the fractional extension of the classical dynamics is introduced. The fractional Hamiltonian on the extended phase space is analyzed and the corresponding generalized Poisson’s brackets are constructed.
Nonlinear Dynamics of Duffing System With Fractional Order Damping
Authors: Cao Junyi , Ma Chengbin , Xie Hang , Jiang Zhuangde
Published: August 2010

In this paper, nonlinear dynamics of Duffing system with fractional order damping is investigated. The fourth-order Runge–Kutta method and tenth-order CFE-Euler method are introduced to simulate the fractional order Duffing equations. The effect of taking fractional order on system dynamics is investigated using phase diagram, bifurcation diagram and Poincaré map. The bifurcation diagram is introduced to exam the effect of excitation amplitude, frequency, and damping coefficient on the Duffing system with fractional order damping. The analysis results show that the fractional order damped Duffing system exhibits periodic motion, chaos, periodic motion, chaos, and periodic motion in turn when the fractional order varies from 0.1 to 2.0. The period doubling bifurcation route to chaos and inverse period doubling bifurcation out of chaos are clearly observed in the bifurcation diagrams with various excitation amplitude, frequency, and damping coefficient.
The Effect of Glisson’s Capsule on the Superficial Elasticity Measurements of the Liver
Authors: Roan Esra
Published: August 2010

In the past decade, novel tools for surgical planning and disease diagnosis have been developed to detect the liver’s mechanical properties. Some tools utilize superficial indentation type measurements to determine the elasticity of the liver parenchyma and to assume material homogeneity. In fact, the liver is a soft tissue covered with a connective sheathing that is called Glisson’s capsule. This article quantifies the effect of this capsule on the measured or “effective” elastic modulus obtained by indentation with a spherical geometry. Two sets of parametric computational studies in which the Glisson capsule thickness and elasticity were varied, demonstrated the relationship between the measured elastic response and the underlying parenchymal elastic response. Previously reported in vivo indentation data on the human liver were utilized to determine the elasticity of its parenchyma. The results indicated a linear relationship between the effective (measured) elastic response and the underlying parenchyma for the Glisson capsule thicknesses considered. When previously published human liver indentation data were analyzed, the measured elastic modulus was nearly 6.9% greater than the underlying parenchyma elastic modulus. Although the analyzed data were obtained from a single liver and yet displayed a significant variation, the Glisson capsule elasticity induced a significant but systematic error as well. The Glisson capsule thickness error was negligible for capsule parameters associated with a normal liver. Based on this work, an emphasis on the Glisson capsule’s contribution to the mechanical response of the liver would enhance the clinical potential of indentation-based novel tools for liver care.
Radial Transport Along the Human Acinar Tree
Authors: Henry F. S. , Tsuda A.
Published: August 2010

A numerical model of an expanding asymmetric alveolated duct was developed and used to investigate lateral transport between the central acinar channel and the surrounding alveoli along the acinar tree. Our results indicate that some degree of recirculation occurs in all but the terminal generations. We found that the rate of diffusional transport of axial momentum from the duct to the alveolus was by far the largest contributor to the resulting momentum in the alveolar flow but that the magnitude of the axial momentum is critical in determining the nature of the flow in the alveolus. Further, we found that alveolar flow rotation, and by implication chaotic mixing, is strongest in the entrance generations. We also found that the expanding alveolus provides a pathway by which particles with little intrinsic motion can enter the alveoli. Thus, our results offer a possible explanation for why submicron particles deposit preferentially in the acinar-entrance region.
Local State Space Temporal Fluctuations: A Methodology to Reveal Changes During a Fatiguing Repetitive Task
Authors: Sanjari Mohammad Ali , Arshi Ahmad Reza , Parnianpour Mohamad , Seyed-Mohseni Saeedeh
Published: August 2010

The effect of muscular fatigue on temporal and spectral features of muscle activities and motor performance, i.e., kinematics and kinetics, has been studied. It is of value to quantify fatigue related kinematic changes in biomechanics and sport sciences using simple measurements of joint angles. In this work, a new approach was introduced to extract kinematic changes from 2D phase portraits to study the fatigue adaptation patterns of subjects performing elbow repetitive movement. This new methodology was used to test the effect of load and repetition rate on the temporal changes of an elbow phase portrait during a dynamic iso-inertial fatiguing task. The local flow variation concept, which quantifies the trajectory shifts in the state space, was used to track the kinematic changes of an elbow repetitive fatiguing task in four conditions (two loads and two repetition rates). Temporal kinematic changes due to muscular fatigue were measured as regional curves for various regions of the phase portrait and were also expressed as a single curve to describe the total drift behavior of trajectories due to fatigue. Finally, the effect of load and repetition rate on the complexity of kinematic changes, measured by permutation entropy, was tested using analysis of variance with repeated measure design. Statistical analysis showed that kinematic changes fluctuated more (showed more complexity) under higher loads (p=0.014), but did not differ under high and low repetition rates (p=0.583). Using the proposed method, new features for complexity of kinematic changes could be obtained from phase portraits. The local changes of trajectories in epochs of time reflected the temporal kinematic changes in various regions of the phase portrait, which can be used for qualitative and quantitative assessment of fatigue adaptation of subjects and evaluation of the influence of task conditions (e.g., load and repetition rate) on kinematic changes.
A Linear Laser Scanner to Measure Cross-Sectional Shape and Area of Biological Specimens During Mechanical Testing
Authors: Vergari Claudio , Pourcelot Philippe , Holden Laurène , Ravary-Plumioën Bérangère , Laugier Pascal , Mitton David , Crevier-Denoix Nathalie
Published: August 2010

Measure of the cross-sectional area (CSA) of biological specimens is a primary concern for many biomechanical tests. Different procedures are presented in literature but besides the fact that noncontact techniques are required during mechanical testing, most of these procedures lack accuracy or speed. Moreover, they often require a precise positioning of the specimen, which is not always feasible, and do not enable the measure of the same section during tension. The objective of this study was to design a noncontact, fast, and accurate device capable of acquiring CSA of specimens mounted on a testing machine. A system based on the horizontal linear displacement of two charge-coupled device reflectance laser devices next to the specimen, one for each side, was chosen. The whole measuring block is mounted on a vertical linear guide to allow following the measured zone during sample tension (or compression). The device was validated by measuring the CSA of metallic rods machined with geometrical shapes (circular, hexagonal, semicircular, and triangular) as well as an equine superficial digital flexor tendon (SDFT) in static condition. We also performed measurements during mechanical testing of three SDFTs, obtaining the CSA variations until tendon rupture. The system was revealed to be very fast with acquisition times in the order of 0.1 s and interacquisition time of about 1.5 s. Measurements of the geometrical shapes yielded mean errors lower than 1.4% (n=20 for each shape) while the tendon CSA at rest was 90.29±1.69 mm2(n=20). As for the tendons that underwent tension, a mean of 60 measures were performed for each test, which lasted about 2 min until rupture (at 20 mm/min), finding CSA variations linear with stress (R2>0.85). The proposed device was revealed to be accurate and repeatable. It is easy to assemble and operate and capable of moving to follow a defined zone on the specimen during testing. The system does not need precise centering of the sample and can perform noncontact measures during mechanical testing; therefore, it can be used to measure variations of the specimen CSA during a tension (or compression) test in order to determine, for instance, the true stress and transverse deformations.
Optimized Condition for Buffer Gas in Optical-Pumped Magnetometer Operated at Room Temperature
Authors: Kawabata Ryuzo , Fukuda Kyoya , Kandori Akihiko
Published: August 2010

The optimal buffer-gas condition for achieving low noise in room temperature optical-pumped magnetometers (OPMs) was determined. To find this optimal condition, various buffer gases (helium, neon, argon, and nitrogen) filled in cesium cells at pressures of 1, 10, 50, 300, or 1000 Torr were tested. Magnetic-resonance signal was detected by sweeping rf frequency, and maximum intensity (I
max) and line width (Δf) in the magnetic-resonance spectra were measured. As an appropriate figure of merit for OPMs, the “α value” (i.e., I
max/Δf) is defined. It was found that the α value of the cells decreased as gas pressure increased. The α value obtained from the cell filled with neon gas (at 1 Torr) at optimal rf field of 50 nT was the largest. It was inferred from these results that the spin-destruction collision between cesium atoms and the buffer gas has a significant influence on the α value.
Correlation between Extrinsic Electroresistance and Magnetoresistance in Fine-Grained La0.7Ca0.3MnO3
Authors: Devi Parukuttyamma Sujatha , Kumar Abhoy , Bhattacharya Dipten , Karmakar Shilpi , Chaudhuri Bijoy Krishna
Published: August 2010

We report our observation of a correlation between the extrinsic electroresistance (EER) and magnetoresistance (EMR) via grain size in fine-grained La0.7Ca0.3MnO3. The nature of dependence of EER and EMR on grain size (∼0.2–1.0 µm) indicates that for finer grains with low-resistive boundaries both of them follow similar trend whereas they differ for coarser grains with high-resistive boundaries. This could be due to a crossover in the mechanism of charge transport across the grain boundaries – from spin-dependent scattering process to spin-polarized tunneling one – as a function of grain size.
Green Electroluminescence from Metal–Oxide–Semiconductor Devices Fabricated by Spin Coating of Terbium Organic Compounds on Silicon
Authors: Ohzone Takashi , Matsuda Toshihiro , Hase Souta , Nohara Shingo , Iwata Hideyuki
Published: August 2010

Current–voltage (I
G–V
G) and electroluminescence (EL) characteristics are reported for indium–tin oxide (ITO)/Tb–Si–O layer/n+-Si metal–oxide–semiconductor (MOS) devices. The Tb–Si–O layer was fabricated from a Tb organic compound film, which was spin-coated on an n+-Si substrate and annealed with temperatures from 700 to 1000 °C for 30 min in air. The EL intensity increased proportionally to the supply current, and it also increased with annealing temperature at the same current. The EL device emitted green light with four photon energy peaks at 2.52 eV (492 nm), 2.27 eV (547 nm), 2.11 eV (589 nm), and 1.99 eV (623 nm), which originated from the intrashell transitions of 5D4–7F
J
(J = 6, 5, 4, and 3) of Tb3+ ions excited by hot electrons. The surface layers on the Si substrate have a total thickness of about 30 nm and consist of a Tb2O3 layer, and a mixture layer of Tb2O3 and Tb–Si–O depending on the annealing temperature.
A New Liquid Crystal Fringe-Field Switching Device with Superior Outdoor Readability
Authors: Seen Seung Min , Kim Mi Sook , Lee Seung Hee
Published: August 2010

A new liquid crystal (LC) device driven by fringe-field switching (FFS) with superior outdoor readability is proposed. In this structure, the bottom substrate has patterned floating metals which are positioned below the center of the pixel electrode and the center between pixel electrodes and above metals, in-cell retarder with quarter wave phase retardation (QWPR) exists and under them, compensation film with QWPR does. And light efficiency at these positions becomes maximal under any lighting conditions. As a result, it is possible for the new device to show both a single cell gap and superior outdoor readability even though it's not a transflective LC display.
Molecular Dynamics Simulation of Heat Transport in a Nanoribbon by the Thermal Wave at Different Durations of Pulse Heating
Authors: Zolotoukhina Tatiana , Kawaguchi Hiroki , Iwaki Toshihiro
Published: August 2010

In recent year, progress has been made in the study of ballistic heat flow and phonon scattering by phonon spectroscopy and phonon-imaging techniques. Regarding the femtosecond laser application to nanostructures, phonon generation in nanoscale electronics is the focus of interest in the investigation of the mechanism of thermal wave formation at different heating pulses and conditions for heat flux propagation in nanostructures. We test an atomic model of thermal transport in a nanoribbon after a few picosecond pulse heating that leads to the simultaneous presence of two modes, namely, coherent phonons and diffusion, by molecular dynamics (MD) simulation. Our main goal is to investigate the characteristics of the highest magnitude vibrational motion of wave front atoms at different heating pulses and ascertain their correspondence to a single longitudinal optical phonon. To this end it is shown that in the MD model, the equations of heat flux taken through the boundaries of a corresponding sampling area can resolve coherent phonon motion with high resolution when translational and vibrational modes are evaluated separately. Such a definition of heat flux allows the tracing of formation and dynamics of a single phonon. It is applied for different times of heating of a nanoribbon sample. The mechanism underlying the decay of phonons into diffusion is also probed, and energy conversion over the nanoribbon is evaluated. The relevant size of the area for the temporal and spatial flux resolution of a coherent phonon in the MD model is confirmed.
Radial Distribution of Active Impurities in Individual In situ Boron-Doped Silicon Nanowires: A Raman Scattering Study
Authors: Nishimura Chiharu , Fujii Minoru , Kawashima Takahiro , Saitoh Tohru , Hayashi Shinji
Published: August 2010

The radial distribution of electrically active B in individual in situ B-doped Si nanowires (SiNWs) grown by the vapor liquid solid (VLS) process is studied by combining micro-Raman spectroscopy and wet chemical etching. The etching of the surface layer results in significant changes in the Raman spectra; Fano-type asymmetry, which is a characteristic of heavily doped p-type Si, disappears and the spectra become almost symmetric. The Raman data reveal that the as-grown B-doped SiNWs consist of a heavily B-doped shell and an almost intrinsic core.
Electron Tunneling through a Trapezoidal Barrier in Graphene
Authors: Xu Xuguang , Xu Gongjie , Cao Juncheng
Published: August 2010

We have investigated the electron tunneling through a trapezoidal barrier in graphene. The dependence of the transmission on the applied bias is obtained. The trapezoidal barrier removes the negative differential resistance in the current–voltage characteristics. Furthermore the slope of the trapezoidal barrier can also be used as a parameter to control the angular distribution of the transmitted electrons. The result can be used to design graphene-based tunneling devices such as an energy filter.
Polymorphs of Rubrene Crystal Grown from Solution
Authors: Matsukawa Takeshi , Yoshimura Masashi , Uchiyama Masahito , Yamagishi Masakazu , Nakao Akiko , Takahashi Yoshinori , Takeya Junichi , Kitaoka Yasuo , Mori Yusuke , Sasaki Takatomo
Published: August 2010

Single crystals of rubrene were grown by slow cooling of solutions in various solvents. Hexagonal single crystals were obtained from p-xylene, whereas parallelogram-shaped crystals were grown from aniline. Both types of crystal were obtained from propan-1-ol. Single-crystal X-ray diffraction analyses showed that the hexagonal and parallelogram-shaped crystals belonged to the orthorhombic system and the triclinic system, respectively. The triclinic crystals showed much poorer carrier mobilities than did the orthorhombic crystals.
Structural Effects on Thermal Conductivity of SiGeAu Superlattice Thin Films
Authors: Okamoto Yoichi , Saeki Junichi , Ohstuki Testunari , Takiguchi Hiroaki
Published: August 2010

We have measured the thermal conductivity of thin films and discussed the relationship between the thermal conductivity and structure of thin films. All samples had a very low thermal conductivity compared with a conventional bulk sample. The thermal conductivity changed depending on the sample structure. The thermal conductivity decreased with the existence of the artificial superlattice structure and the phase transition to the amorphous phase.
Effect of Nitrogen Plasma Treatment on Electrical Characteristics for Pd Nanocrystals in Nonvolatile Memory
Authors: Kang Tsung-Kuei , Liao Ta-Chuan , Lin Cheng-Li , Wu Wen-Fa
Published: August 2010

Pd nanocrystals (NCs) are successfully embedded in a TaN/SiO2/HfAlO/Si structure. The initial memory window increases at a higher rate with increasing fabrication temperature of Pd NCs compared with the linear variation of Pd NC density, which is related to the thermally induced neutral traps in the HfAlO film around Pd NCs. After manufacturing a TaN/SiO2/Pd NCs/HfAlO/Si/Al structure, the subsequent N2 plasma treatment is conducted at 300 °C for 3 min. The number of leakage current paths in the SiO2 blocking layer adjacent to TaN is clearly reduced, but that of leakage current paths in SiO2/HfAlO around Pd NCs is slightly increased owing to the thermal stress. The thermally induced neutral traps in the HfAlO film around the Pd NCs can be passivated by nitrogen atoms, which leads to the improvement of the final memory window for the Pd NC samples fabricated at 600–700 °C. However, the intrinsic traps in the HfAlO film play an important role in memory characteristic and the final memory window is reduced by thermal densification for the Pd NC samples fabricated at 500 °C.
Dielectric Relaxation Analysis of Single-Stranded DNA in Liquid Crystals
Authors: Iwabata Kazuki , Nakabayashi Tadashi , Uchiyama Yukinobu , Inoue Masaru , Taki Shingo , Ando Kazuyuki , Sakai Hideki , Abe Masahiko , Itagaki Masayuki , Furue Hirokazu , Kobayashi Shunsuke , Sakaguchi Kengo
Published: August 2010

Since liquid crystals have found wide use in liquid crystal displays, we try to apply liquid crystals to biotechnology. The purpose of this study is to describe the physical properties of the biopolymer DNA in regard to electrooptics. Synthetic oligonucleotide molecules were dispersed in a nematic liquid crystal (NLC). The ICP analyses showed that all of the oligonuleotide molecules added dispersed in the NLC. This sample was injected into the twisted nematic liquid crystal display cells, and then we measured its dielectric properties. The NLC doped with oligonucleotide molecules exhibited dielectric relaxation characteristics, depending on the concentration of oligonucleotide molecules. After analyzing this effect by using the equivalent circuit model, we found a difference in electrical conductivity between Watson–Crick base pairs (AT and GC). This result suggests that the difference might have contributed to the existence of a functional group involved in the hydrogen-bond interaction.
Effect of Microwave Non thermal Plasma Irradiation on the Adsorptive Properties of Active Carbon Preliminarily Impregnated with Poly(vinyl alcohol)
Authors: Ueshima Masato , Toda Eriko , Nakajima Yuki , Sugiyama Kazuo
Published: August 2010

Microwave non thermal plasma irradiation was conducted on active carbon (AC) preliminarily impregnated with poly(vinyl alcohol) (PVA) in order to modify the adsorption properties of active carbon, particularly to increase hydrophobicity. The plasma was produced by applying microwave power on the PVA-impregnated active carbon (PVA/AC) placed in a low vacuum chamber (<10 Torr). The surface of the plasma-treated PVA/AC was imaged using scanning electron microscopy and atomic force microscopy (SEM and AFM, respectively), and analyzed using X-ray photoelectron spectroscopy (XPS). Hydrophobicity of the plasma-treated PVA/AC was compared to that of untreated PVA/AC and AC by a sinking test in water/methanol mixed solutions. The hydrophobicity drastically increased for PVA/AC treatment with 1-min plasma irradiation. The AFM results indicated that the surface roughness of the PVA/AC was dependent upon the hydrophobicity, rather than reduction of free energy due to reduction of polarized functional groups. NaOH and HCl adsorption onto the plasma-treated PVA/AC was also measured. Adsorption capacity of plasma-treated PVA/AC increased for NaOH, whereas it decreased for HCl. The plasma treatment not only increased the hydrophobicity of PVA/AC, but also changed its acid-base adsorption properties. We have developed a new material based on active carbon, which is light, hydrophobic and electrically conductive by using a combination of PVA sintering and plasma irradiation.
Threshold Voltage Instability Induced by Plasma Process Damage in Advanced Metal–Oxide–Semiconductor Field-Effect Transistors
Authors: Eriguchi Koji , Nakakubo Yoshinori , Matsuda Asahiko , Kamei Masayuki , Takao Yoshinori , Ono Kouichi
Published: August 2010

The effects of plasma process-induced physical damage on n-channel metal–oxide–semiconductor field-effect transistor (MOSFET) performance were investigated in detail in terms of threshold voltage (Vth) andVthshift (ΔVth). The Si recess structure formed by ion bombardment was primarily focused on in this study. Defect site density was also considered as a possible cause of ΔVth. The damaged structure and damage formation mechanisms were studied using an optical analysis technique and classical molecular dynamics simulations. The plasma-induced ΔVthof devices with various recess depths was estimated by technology computer-aided design (TCAD) simulations, by taking into account the bias power dependence of damaged layer thickness. TheVthrelated to the recess structure shifts toward the negative direction in n-channel MOSFETs, indicating an increase in off-state leakage current (IOFF). |ΔVth| proportionally increases with the increasing recess depthdR(∼ bias power), while the underlying defect density does not affect ΔVth. Moreover, the predictedVthdecrease (ΔVth<0) with an increase indRstrongly depends on gate length (Lg), i.e., the decrement inVthis inversely proportional toLg. This suggests that thedRincrease induces an exponential increase in the standby power consumption of advanced devices. We provide a comprehensive relationship between device parameters (Vth,Ioff, andLg) and process parameters for plasma-damaged devices.
Application of a Temperature Gradient Type Thermal Probe to the Discharge Plasma
Authors: Matsuura Hiroto , Nakano Ken , Kado Shinichiro
Published: August 2010

Thermal probes have been proposed to measure the plasma heat flux and to deduced the plasma parameters. Their time response is, however, rather poor, due to the steady-state condition where they work. In this work, a new type thermal probe with three thermocouples is designed and tested for low density discharge plasma. Monitering of heat flux changes due to discharge condition changes is successfully demonstrated. The measurement limit and the error for this probe are also discussed.
Atomic-Scale Cellular Model and Profile Simulation of Si Etching: Analysis of Profile Anomalies and Microscopic Uniformity
Authors: Tsuda Hirotaka , Mori Masahito , Takao Yoshinori , Eriguchi Koji , Ono Kouichi
Published: August 2010

Reactive ion etching (RIE) has been used in the manufacture of semiconductor integrated circuit devices. However, the formation mechanisms of profile anomalies and microscopic uniformity have been poorly understood until now. In this paper, we focus on the analysis of formation mechanisms of profile anomalies and microscopic uniformity during plasma etching of Si in Cl2 plasmas, using our own atomic-scale cellular model (ASCeM). The numerical results indicated that high neutral-to-ion flux ratios result in microtrench formation. Moreover, RIE lag tends to occur at low neutral-to-ion flux ratios (<50), whereas inverse RIE lag occurs at high neutral-to-ion flux ratios in typical low-pressure and high-density plasmas. In particular, the etch rates for narrow patterns (<70 nm) increase significantly with increasing neutral-to-ion flux ratio. The synergistic effects between ion-enhanced etching and neutral shadowing in microstructural features play a significant role in the formation of profile anomalies.
Hybrid White Organic Light-Emitting Diodes with Reduced Efficiency Roll-Off
Authors: Seo Ji Hoon , Park Jung Sun , Koo Ja Ryong , Seo Bo Min , Lee Kum Hee , Park Jeong Keun , Yoon Seung Soo , Kim
Published: August 2010

The authors have demonstrated hybrid white organic light-emitting diodes (HWOLEDs) with reduced efficiency roll-off. It was shown that HWOLEDs fabricated with {9,9-dimethyl-7-[10-(naphthalen-2-yl)anthracen-9-yl]-9H-fluoren-2-yl} triphenylsilane (ANFTPS) as the blue host have the maximum external quantum efficiency of 9.92%, power efficiency of 14.51 lm/W, and reduced efficiency roll-off 2.0 times that of the control white device. The deep highest occupied molecular orbital of ANFTPS of the optimized white device adequately brocks holes and confines excitons in emitting layers. The white device also exhibited a more stable color shift from low to high current density than did the control white device.
Towards a Flat Rotating Flexible Disk for High Speed Optical Data Storage
Authors: Gad Abdelrasoul M. M. , Rhim Yoon Chul
Published: August 2010

A flexible optical disk system, which consists of a thin optical disk and a rigid stabilizer, has recently introduced as the next-generation optical storage media. The present work introduces a new design for the stabilizer that helps to hold the rotating flexible optical disk almost flat and thereby reducing its axial run-out at high rotational speeds; the new design incorporates an axisymmetrically curved active surface of the stabilizer. The combination of the stabilizer curvature and disk rotation generates moderate air-film forces that balance the disk mechanical forces and reduces the disk axial run-out considerably. With a proper combination of the stabilizer geometrical parameters, the out-of-flatness as well as the axial run-out of the disk could be reduced to less than 10 µm. The significant decrease in the axial run-out at rotational speed of 10,000 rpm is primarily due to the flatness of the disk.
High-Speed Flexible Optical Disk for Broadcast Archival Storage
Authors: Koide Daiichi , Kajiyama Takeshi , Tokumaru Haruki , Takano Yoshimichi , Onagi Nobuaki , Aman Yasutomo , Ohishi Kiyoshi
Published: August 2010

We developed a prototype of a flexible optical disk (FOD) drive with a mechanical stabilizer. We prepared the FOD that had a high recording sensitivity of a recording layer and had low byte error rates below 2 ×10-4 at speeds from 36 to 252 Mbps, and examined the recording of video data on the FOD and the drive. We could record and play a high-definition television (HDTV) video (MPEG-2, 422P@HL) seamlessly at 144 Mbps over the entire area of the FOD and the FOD drive with broadcast video systems. We confirmed that the FOD and the FOD drive can record and play HDTV signals for professional broadcast use.
Error Prediction Robust Tracking Control System Suppressing Harmonics Disturbance for Optical Disk Recording System
Authors: Kamigaki Yoshiya , Ohishi Kiyoshi , Miyazaki Toshimasa , Koide Daiichi , Tokumaru Haruki , Takano Yoshimichi
Published: August 2010

Recently, the memory capacity of media for the optical disk recording system has been increasing. The disk rotation speed has been increasing depending on the large memory capacity. However, the optical disk recording system has both periodic primary disturbance and periodic harmonics disturbance. Hence, the tracking control of the optical disk recording system is requested to maintain a high-precision tracking performance. We have proposed the robust tracking controller and zero-phase error tracking feed-forward control systems. Results of our study show that the primary disturbance is well suppressed by our conventional method, but it is difficult for our conventional method to suppress the harmonics disturbance. To overcome this problem, in this paper, we propose a new error prediction robust tracking control system suppressing harmonic disturbance. The experimental results show that the proposed tracking control system has a precise tracking response against both periodic primary disturbance and periodic harmonics disturbance.
Neuro-Interpolator for Holographic Data Storage
Authors: Osawa Hisashi , Yamashita Masato , Okamoto Yoshihiro , Nakamura Yasuaki
Published: August 2010

The neuro-interpolator (NI) integrating the interpolator with neural network equalizer is proposed to reduce the influence of interpixel interference in holographic data storage. The simplification of NI is performed by using a hybrid genetic algorithm based on a new mutation method. The bit error rate performance of the simplified NI is superior to that of the interpolator alone. Furthermore, the number of connections in the simplified NI is reduced to about half of that obtained by using a conventional mutation method.
Microholographic Recording Using Single-Sided Optics with Electrical Beam Control
Authors: Katayama Ryuichi , Komatsu Yuichi , Natsumeda Masanao
Published: August 2010

A single-sided optics with electrical beam control for microholographic recording has been proposed, and its principle has been experimentally demonstrated. The recording medium has a quarter-wave layer and a reflective layer, which makes it possible to restrict an unwanted interference during recording and to eliminate an unwanted beam during readout, thereby improving the recording and readout performances. Liquid crystal deflectors and liquid crystal variable-focus lenses were used for electrical beam control, which leads to high reliability and low power consumption. The former and the latter move the focal position in the in-plane and vertical directions, respectively. Three bits were successfully recorded and read out in both the in-plane and vertical directions. Future work includes the development and demonstration of a coaxial single-sided optics, which features robustness and simplicity.
Study of Ga Adsorption Structure on Ni/Si(100) Surface by Scanning Tunneling Microscopy
Authors: Hara Shinsuke , Fuse Kazuhiro , Suzuki Toru , Yagishita Kazuki , Hirata Yoshiki , Irokawa Katsumi , Miki Hirofumi , Kawazu Akira , Fujishiro Hiroki I.
Published: August 2010

The Ga adsorption structures on the Ni-induced Si(100) surface have been studied by scanning tunneling microscopy. The protrusions, which are different from Ga ad-dimer, are observed on the dimer vacancy lines (DVLs) after the Ga ad-dimers cover the Si region. The amount of protrusions increases as Ga coverage increases and these protrusions occupy the DVLs at about 0.50 monolayer. The type of protrusions on the DVLs is similar to the precursor state of the Ga clusters. Islands of different sizes are formed locally on the steps and terraces as coverage increases. Small islands are distributed evenly on the terraces after annealing the surface at 200 °C, whereas large islands are formed again at 400 °C. The changes in the distribution of the islands are associated with the nuclei sites on the DVLs and the transformation of the surface structure.
Operation of Self-Sensitive Cantilever in Liquid for Multiprobe Manipulation
Authors: Iwata Futoshi , Mizuguchi Yuya , Ozawa Kousuke , Ushiki Tatuo
Published: August 2010

We describe a novel and simple operation method of using a self-sensitive cantilever of an atomic force microscopy (AFM) system in liquid. As for operation of the cantilever in liquid, Al lines of an integrated piezoresistor patterned on the cantilever are easily damaged by electrochemical corrosion. To realize safe operation without the damage, an additional electrode was inserted into the liquid. By applying DC voltage and controlling the potential of the electrode, the Al lines of the piezoresistor circuit on the cantilever could be protected from the electrochemical corrosion. By using this method, AFM imaging of collagen fibrils was demonstrated in physiological saline. Furthermore, the technique allowed us to realize a multiprobe AFM system with a simple configuration. Two cantilever probes were successfully operated like a knife and fork for the manipulation of collagen fibers in liquid.
Sustained hyperoxia stabilizes breathing in healthy individuals during NREM sleep
Authors: Chowdhuri Susmita , Sinha Prabhat , Pranathiageswaran Sukanya , Safwan Badr M.
Published: August 2010

The present study was designed to determine whether hyperoxia would lower the hypocapnic apneic threshold (AT) during non-rapid eye movement (NREM) sleep. Nasal noninvasive mechanical ventilation was used to induce hypocapnia and subsequent central apnea in healthy subjects during stable NREM sleep. Mechanical ventilation trials were conducted under normoxic (room air) and hyperoxic conditions (inspired Po2 > 250 Torr) in a random order. The CO2 reserve was defined as the minimal change in end-tidal Pco2 (PetCO2) between eupnea and hypocapnic central apnea. The PetCO2 of the apnea closest to eupnea was designated as the AT. The hypocapnic ventilatory response was calculated as the change in ventilation below eupnea for a given change in PetCO2. In nine participants, compared with room air, exposure to hyperoxia was associated with a significant decrease in eupneic PetCO2 (37.5 ± 0.6 vs. 41.1 ± 0.6 Torr, P = 0.001), widening of the CO2 reserve (−3.8 ± 0.8 vs. −2.0 ± 0.3 Torr, P = 0.03), and a subsequent decline in AT (33.3 ± 1.2 vs. 39.0 ± 0.7 Torr; P = 001). The hypocapnic ventilatory response was also decreased with hyperoxia. In conclusion, 1) hyperoxia was associated with a decreased AT and an increase in the magnitude of hypocapnia required for the development of central apnea. 2) Thus hyperoxia may mitigate the effects of hypocapnia on ventilatory motor output by lowering the hypocapnic ventilatory response and lowering the resting eupneic PetCO2, thereby decreasing plant gain.
Heat acclimation improves exercise performance
Authors: Lorenzo Santiago , Halliwill John R. , Sawka Michael N. , Minson Christopher T.
Published: August 2010

This study examined the impact of heat acclimation on improving exercise performance in cool and hot environments. Twelve trained cyclists performed tests of maximal aerobic power (V̇o2max), time-trial performance, and lactate threshold, in both cool [13°C, 30% relative humidity (RH)] and hot (38°C, 30% RH) environments before and after a 10-day heat acclimation (∼50% V̇o2max in 40°C) program. The hot and cool condition V̇o2max and lactate threshold tests were both preceded by either warm (41°C) water or thermoneutral (34°C) water immersion to induce hyperthermia (0.8–1.0°C) or sustain normothermia, respectively. Eight matched control subjects completed the same exercise tests in the same environments before and after 10 days of identical exercise in a cool (13°C) environment. Heat acclimation increased V̇o2max by 5% in cool (66.8 ± 2.1 vs. 70.2 ± 2.3 ml·kg−1·min−1, P = 0.004) and by 8% in hot (55.1 ± 2.5 vs. 59.6 ± 2.0 ml·kg−1·min−1, P = 0.007) conditions. Heat acclimation improved time-trial performance by 6% in cool (879.8 ± 48.5 vs. 934.7 ± 50.9 kJ, P = 0.005) and by 8% in hot (718.7 ± 42.3 vs. 776.2 ± 50.9 kJ, P = 0.014) conditions. Heat acclimation increased power output at lactate threshold by 5% in cool (3.88 ± 0.82 vs. 4.09 ± 0.76 W/kg, P = 0.002) and by 5% in hot (3.45 ± 0.80 vs. 3.60 ± 0.79 W/kg, P < 0.001) conditions. Heat acclimation increased plasma volume (6.5 ± 1.5%) and maximal cardiac output in cool and hot conditions (9.1 ± 3.4% and 4.5 ± 4.6%, respectively). The control group had no changes in V̇o2max, time-trial performance, lactate threshold, or any physiological parameters. These data demonstrate that heat acclimation improves aerobic exercise performance in temperate-cool conditions and provide the scientific basis for employing heat acclimation to augment physical training programs.