bluuebunny/crossref_metadata_2025 huggingface dataset:
ELECTRONICALLY-CONTROLLABLE FLOATING INDUCTOR USING OPERATIONAL MIRRORED AMPLIFIER
Authors: SHARMA R. K. , SENANI R. , BHASKAR D. R. , SINGH A. K. , GUPTA S. S.
Published: March 2009

The operational mirrored amplifiers (OMA) were introduced as useful building blocks for facilitating an easy realization of floating impedances (in conjunction with RC elements) as compared to other approaches of floating impedance simulation. In this paper, we present a new formulation, for realizing a floating inductance (FI) using an OMA which takes into account the dominant pole of the op-amp employed in the OMA and hence, does not require any external capacitor. Moreover, when the only external resistor employed is replaced by an electronically-controlled resistance, the resulting circuit permits an electronically controllable floating inductance. The workability of the proposed FI has been demonstrated by PSPICE simulations.
A SELF-OSCILLATING SWITCHING POWER AMPLIFIER
Authors: KAO C. H. , TSAI P. Y. , LIN W. P. , CHOU M. C.
Published: March 2009

A self-oscillating switching power amplifier is proposed. We use feedback to reduce the output DC bias current and to produce self-oscillation. Further, filters are added in the feedback loop to reduce the quantization noise. The experimental results show that the proposed circuit has 0.25% total harmonic distortion (THD) and the efficiency of output power of 840 μW reaches 90.1% while the DC output bias current is 8 μA and the supply voltage is 1.5 V.
LOW CLOCK-SWING TSPC FLIP-FLOPS FOR LOW-POWER APPLICATIONS
Authors: HU YINGBO , ZHOU RUNDE
Published: March 2009

In this paper, two types of Low Clock-Swing True Single Phase Clock (TSPC) Flip-Flops suitable for low-power applications are proposed. One is Low Clock-Swing Edge-Triggered TSPC Flip-Flop (LCSETTFF), constructed with a negative TSPC split out latch and a positive TSPC split out latch. The other is Low Clock-Swing Pulse-Triggered TSPC Flip-Flop (LCSPTTFF), developed in several styles. A double-edge triggered pulse generator is also developed for LCSPTTFF. With low threshold voltage clock transistors adopted, great power efficiency can be obtained in the clock network. Both types of Flip-Flops have advantages of simple structure, low power and much lower clock network power dissipation. All proposed circuits are simulated in HSPICE with 0.18 μm CMOS technology. Simulation results show that the power of LCSETTFF can be reduced by 42%, while the power dissipation, Power-Delay Product (PDP) and Area-Power-Delay Product (APDP) of LCSPTTFF can be reduced by 45–60%, 11–27% and 58–65%, respectively. In addition, the power consumptions of clock network of LCSPTTFF and LCSETTFF are estimated to be reduced by 78% and 56%, respectively, compared with conventional Flip-Flops.
MOS-C TOW-THOMAS FILTER USING VOLTAGE OP AMP, CURRENT FEEDBACK OP AMP AND OPERATIONAL TRANSRESISTANCE AMPLIFIER
Authors: SOLIMAN AHMED M. , MADIAN AHMED H.
Published: March 2009

Several MOS-C realizations of the Tow-Thomas circuit using the commercially available voltage operational amplifier and the current feedback operational amplifier are reviewed in this paper. Additional MOS-C Tow-Thomas realizations using the operational transresistance amplifier and the differential current voltage conveyor are also included. MOS-C realizations of the Tow-Thomas circuit using CMOS operational amplifier, CMOS current feedback operational amplifier and CMOS operational transresistance amplifier are also given. Spice simulation results using 0.18 CMOS technology model from MOSIS are included together with detailed comparison tables to demonstrate the differences between MOS-C Tow-Thomas circuits using both of the commercially available active building blocks and CMOS integrated building blocks.
INTRA-APPLICATION ENERGY REDUCTION FOR MICROPROCESSOR LOW-POWER DESIGN
Authors: XIA XIAO XIN , TAY TENG TIOW
Published: March 2009

Energy consumption is one of the most important design constraints for modern microprocessors, and designers have proposed many energy-saving techniques. Looking beyond the traditional hardware low-power designs, software optimization is becoming a significant strategy for the microprocessor to lower its energy consumption. This paper describes an intra-application identification and reconfiguration mechanism for microprocessor energy reduction. Our mechanism employs a statistical sampling method during training runs to identify code sections among application that have appropriate IPC (Instructions per Cycle) values and could make contributions to program runtime energy reduction, and then profiles them to dynamically scale the voltage and frequency of the microprocessor at appropriate points during execution. In our simulation, our approach achieves energy savings by an average of 39% with minor performance degradation, compared to a processor running at a fixed voltage and speed.
CONTINUATION OF CONNECTING ORBITS IN 3D-ODEs (II) : CYCLE-TO-CYCLE CONNECTIONS
Authors: DOEDEL E. J. , KOOI B. W. , VAN VOORN G. A. K. , KUZNETSOV YU. A.
Published: March 2009

In Part I of this paper we have discussed new methods for the numerical continuation of point-to-cycle connecting orbits in three-dimensional autonomous ODE's using projection boundary conditions. In this second part we extend the method to the numerical continuation of cycle-to-cycle connecting orbits. In our approach, the projection boundary conditions near the cycles are formulated using eigenfunctions of the associated adjoint variational equations, avoiding costly and numerically unstable computations of the monodromy matrices. The equations for the eigenfunctions are included in the defining boundary-value problem, allowing a straightforward implementation in AUTO, in which only the standard features of the software are employed. Homotopy methods to find the connecting orbits are discussed in general and illustrated with an example from population dynamics. Complete AUTO demos, which can be easily adapted to any autonomous three-dimensional ODE system, are freely available.
HYPERCHAOS IN THE FRACTIONAL-ORDER RÖSSLER SYSTEM WITH LOWEST-ORDER
Authors: CAFAGNA DONATO , GRASSI GIUSEPPE
Published: March 2009

This Letter analyzes the hyperchaotic dynamics of the fractional-order Rössler system from a time-domain point of view. The approach exploits the Adomian decomposition method (ADM), which generates series solution of the fractional differential equations. A remarkable finding of the Letter is that hyperchaos occurs in the fractional Rössler system with order as low as 3.12. This represents the lowest order reported in literature for any hyperchaotic system studied so far.
A LIE ALGEBRAIC CONDITION OF STABILITY FOR HYBRID SYSTEMS AND APPLICATION TO HYBRID SYNCHRONIZATION
Authors: ZHAO SHOUWEI , SUN JITAO
Published: March 2009

In this paper, we first present a Lie algebraic condition for global exponential stability of linear switched and impulsive systems. By considering a Lie algebra generated by all subsystem matrices and impulsive matrices, when not all of these matrices are Hurwitz/Schur stable we derive a new criterion for global exponential stability of linear switched and impulsive systems. Then a simple sufficient condition in terms of Lie algebra is established for a nonlinear system synchronization using a hybrid switched and impulsive control. As an application, Chua's chaotic circuit's synchronization is investigated by our method while synchronization cannot be achieved with the existing result.
INVARIANT MEASURES FOR HIGHER DIMENSIONAL MARKOV SWITCHING POSITION DEPENDENT RANDOM MAPS
Authors: ISLAM MD SHAFIQUL
Published: March 2009

A higher dimensional Markov switching position dependent random map is a random map where the probabilities of switching from one higher dimension transformation to another are the entries of a stochastic matrix and the entries of stochastic matrix are functions of positions. In this note, we prove sufficient conditions for the existence of absolutely continuous measures for a class of higher dimensional Markov switching position dependent random maps. Our result is a generalization of the result in [Bahsoun & Góra, 2005; Bahsoun et al., 2005].
CRITICAL PERIODS OF PLANAR REVERTIBLE VECTOR FIELD WITH THIRD-DEGREE POLYNOMIAL FUNCTIONS
Authors: YU PEI , HAN MAOAN
Published: March 2009

In this paper, we consider local critical periods of planar vector field. Particular attention is given to revertible systems with polynomial functions up to third degree. It is assumed that the origin of the system is a center. Symbolic and numerical computations are employed to show that the general cubic revertible systems can have six local critical periods, which is the maximal number of local critical periods that cubic revertible systems may have. This new result corrects that in the literature: general cubic revertible systems can at most have four local critical periods.
THE NONDEGENERATE CENTER PROBLEM IN CERTAIN FAMILIES OF PLANAR DIFFERENTIAL SYSTEMS
Authors: GINÉ JAUME , DE PRADA PAZ
Published: March 2009

This paper concerns the nondegenerate center problem in certain families of differential systems in ℝ2. We study the existence of uniformly isochronous centers and the form of their commutators. We also classify all centers of the family of the BiLiénard systems of degree five and the maximum number of limit cycles which can bifurcate from a fine focus.
HERMAN RINGS OF BLASCHKE PRODUCTS OF DEGREE 3
Authors: FUJIMOTO YOSHIHISA
Published: March 2009

Let Fa,λbe the Blaschke product of the form Fa,λ= λz2((z - a)/(1 - āz)) and α denote an irrational number satisfying the Brjuno condition. Henriksen [1997] showed that for any α there exists a constant a0≧ 3 and a continuous function λ(a) such that Fa,λ(a)possesses an Herman ring and also that modulus M(a) of the Herman ring approaches 0 as a approaches a0. It is remarked that the question whether a0= 3 holds or not is open. According to the idea of Fagella and Geyer [2003] we can show that for a certain set of irrational rotation numbers, a0is strictly larger than 3.
COHOMOLOGY AND HOMOLOGY OF ABELIAN GROUPS GRADED KOSZUL–VINBERG ALGEBRAS
Authors: NGUIFFO BOYOM MICHEL , NGAKEU F.
Published: March 2009

We study abelian groups graded (or color) Koszul–Vinberg algebras and their modules. Koszul–Vinberg cohomology and homology of these algebras are studied. As applications, we investigate some extensions of graded algebras and graded modules.
COARSE GRAINED MODELING OF BIOPOLYMERS AND PROTEINS: METHODS AND APPLICATIONS
Authors: LI DECHANG , JI BAOHUA , HWANG KEHCHIH , HUANG YONGGANG
Published: March 2009

Single-molecule mechanics of DNA/RNA, polypeptide and protein has become a new frontier in life sciences. There is an increasing need in participant of researcher in applied mechanics to perform a systematic study on methodologies and basic sciences in molecular mechanics. The wide-applied continuum mechanics may not be applicable in study of the biomolecules. At the same time, the all-atom molecular dynamics method is severely limited by the size and time scales of systems it can simulate. As an alternative, coarse-grained models have recently enjoyed intense interest. Coarse-grained representations combined with enhanced computer power currently allow the simulation of systems of biologically relevant size (submicrometric) and timescale (microsecond or millisecond). In this paper, we reported some progresses we made in the modeling of biomolecules using the coarse-grained methods including, the collapse of biopolymers, the dynamics of HIV-1 protease and the binding dynamics of inhibitors into the protease, aiming to stimulating a broader interest in developing molecular mechanics.
ROBUSTNESS-STRENGTH PERFORMANCE OF HIERARCHICAL ALPHA-HELICAL PROTEIN FILAMENTS
Authors: QIN ZHAO , CRANFORD STEVEN , ACKBAROW THEODOR , BUEHLER MARKUS J
Published: March 2009

An abundant trait of biological protein materials are hierarchical nanostructures, ranging through atomistic, molecular to macroscopic scales. By utilizing the recently developed Hierarchical Bell Model, here we show that the use of hierarchical structures leads to an extended physical dimension in the material design space that resolves the conflict between disparate material properties such as strength and robustness, a limitation faced by many synthetic materials. We report materiomics studies in which we combine a large number of alpha-helical elements in all possible hierarchical combinations and measure their performance in the strength-robustness space while keeping the total material use constant. We find that for a large number of constitutive elements, most random structural combinations of elements (> 98%) lead to either high strength or high robustness, reflecting the so-called banana-curve performance in which strength and robustness are mutually exclusive properties. This banana-curve type behavior is common to most engineered materials. In contrast, for few, very specific types of combinations of the elements in hierarchies (< 2%) it is possible to maintain high strength at high robustness levels. This behavior is reminiscent of naturally observed material performance in biological materials, suggesting that the existence of particular hierarchical structures facilitates a fundamental change of the material performance. The results suggest that biological materials may have developed under evolutionary pressure to yield materials with multiple objectives, such as high strength and high robustness, a trait that can be achieved by utilization of hierarchical structures. Our results indicate that both the formation of hierarchies and the assembly of specific hierarchical structures play a crucial role in achieving these mechanical traits. Our findings may enable the development of self-assembled de novo bioinspired nanomaterials based on peptide and protein building blocks.
MATERIAL CHARACTERIZATION BASED ON INSTRUMENTED AND SIMULATED INDENTATION TESTS
Authors: LIU ZISHUN , HARSONO EDY , SWADDIWUDHIPONG SOMSAK
Published: March 2009

This paper reviews various techniques to characterize material by interpreting load-displacement data from instrumented indentation tests. Scaling and dimensionless analysis was used to generalize the universal relationships between the characteristics of indentation curves and their material properties. The dimensionless functions were numerically calibrated via extensive finite element analysis. The interpretation of load-displacement curves from the established relationships was thus carried out by either solving higher order functions iteratively or employing neural networks. In this study, the advantages and disadvantages of these techniques are highlighted. Several issues in an instrumented indentation test such as friction, size effect and uniqueness of reverse analysis algorithms are discussed. In this study, a new reverse algorithm via neural network models to extract the mechanical properties by dual Berkovich and spherical indentation tests is introduced. The predicted material properties based on the proposed neural network models agree well with the numerical input data.
A NOVEL SCHEME OF STRAIN-CONSTRUCTED POINT INTERPOLATION METHOD FOR STATIC AND DYNAMIC MECHANICS PROBLEMS
Authors: LIU G. R. , ZHANG G. Y.
Published: March 2009

This paper presents a new scheme of strain-constructed point interpolation method (SC-PIM) for static, free and forced vibration analysis of solids and structures using triangular cells. In the present scheme, displacement fields are assumed using shape functions created via the point interpolation method (PIM), which possess the Kronecker delta property facilitating the straightforward enforcement of displacement boundary conditions. Using the generalized gradient smoothing technique, the "smoothed" strains at the middle points of the cells edges are first obtained using the corresponding edge-based smoothing domains and the assumed displacement field. In each triangular background cell, the strains at the vertices are assigned using these smoothed strains in a proper manner, and then piecewisely linear strain fields are constructed by the linear interpolation for each sub-triangular cell using the edge-based "smoothed" strains. With the assumed displacements and constructed linear strain fields, the discretized system equations are created using the Strain Constructed Galerkin (SC-Galerkin) weak form. A number of benchmark numerical examples, including the standard patch test, static, free and forced vibration problems, have been studied and intensive numerical results have demonstrated that the present method possesses the following properties: (1) it works well with the simplest triangular mesh, no additional degrees of freedom and parameters are introduced and very easy to implement; (2) it is at least linearly conforming; (3) it possesses a close-to-exact stiffness: it is much stiffer than the "overly-soft" node-based smoothed point interpolation method (NS-PIM) and much softer than the "overly-stiff" FEM model; (4) the results of the present method are of superconvergence and ultra-accuracy: about one order of magnitude more accurate than those of the linear FEM; (5) there are no spurious non-zeros energy modes found and it is also temporally stable, hence the present method works well for dynamic problems.
Immunological and Inflammatory Functions of the Interleukin-1 Family
Authors: Dinarello Charles A.
Published: March 2009

More than any other cytokine family, the interleukin (IL)-1 family is closely linked to the innate immune response. This linkage became evident upon the discovery that the cytoplasmic domain of the IL-1 receptor type I is highly homologous to the cytoplasmic domains of all Toll-like receptors (TLRs). Thus, fundamental inflammatory responses such as the induction of cyclooxygenase type 2, increased expression of adhesion molecules, or synthesis of nitric oxide are indistinguishable responses of both IL-1 and TLR ligands. Both families nonspecifically affect antigen recognition and lymphocyte function. IL-1β is the most studied member of the IL-1 family because of its role in mediating autoinflammatory diseases. Although the TLR and IL-1 families evolved to assist in host defense against infection, unlike the TLR family, the IL-1 family also includes members that suppress inflammation, both specifically within the IL-1 family but also nonspecifically for TLR ligands and the innate immune response.
Regulation and Function of NF-κB Transcription Factors in the Immune System
Authors: Vallabhapurapu Sivakumar , Karin Michael
Published: March 2009

The mammalian Rel/NF-κB family of transcription factors, including RelA, c-Rel, RelB, NF-κB1 (p50 and its precursor p105), and NF-κB2 (p52 and its precursor p100), plays a central role in the immune system by regulating several processes ranging from the development and survival of lymphocytes and lymphoid organs to the control of immune responses and malignant transformation. The five members of the NF-κB family are normally kept inactive in the cytoplasm by interaction with inhibitors called IκBs or the unprocessed forms of NF-κB1 and NF-κB2. A wide variety of signals emanating from antigen receptors, pattern-recognition receptors, receptors for the members of TNF and IL-1 cytokine families, and others induce differential activation of NF-κB heterodimers. Although work over the past two decades has shed significant light on the regulation of NF-κB transcription factors and their functions, much progress has been made in the past two years revealing new insights into the regulation and functions of NF-κB. This recent progress is covered in this review.
Primary B Cell Immunodeficiencies: Comparisons and Contrasts
Authors: Conley Mary Ellen , Dobbs A. Kerry , Farmer Dana M. , Kilic Sebnem , Paris Kenneth , Grigoriadou Sofia , Coustan-Smith Elaine , Howard Vanessa , Campana Dario
Published: March 2009

Sophisticated genetic tools have made possible the identification of the genes responsible for most well-described immunodeficiencies in the past 15 years. Mutations in Btk, components of the pre-B cell and B cell receptor (λ5, Igα, Igβ), or the scaffold protein BLNK account for approximately 90% of patients with defects in early B cell development. Hyper-IgM syndromes result from mutations in CD40 ligand, CD40, AID, or UNG in 70–80% of affected patients. Rare defects in ICOS or CD19 can result in a clinical picture that is consistent with common variable immunodeficiency, and as many as 10% of patients with this disorder have heterozygous amino acid substitutions in TACI. For all these disorders, there is considerable clinical heterogeneity in patients with the same mutation. Identifying the genetic and environmental factors that influence the clinical phenotype may enhance patient care and our understanding of normal B cell development.
Regulatory Lymphocytes and Intestinal Inflammation
Authors: Izcue Ana , Coombes Janine L. , Powrie Fiona
Published: March 2009

The immune system is pivotal in mediating the interactions between host and microbiota that shape the intestinal environment. Intestinal homeostasis arises from a highly dynamic balance between host protective immunity and regulatory mechanisms. This regulation is achieved by a number of cell populations acting through a set of shared regulatory pathways. In this review, we summarize the main lymphocyte subsets controlling immune responsiveness in the gut and their mechanisms of control, which involve maintenance of intestinal barrier function and suppression of chronic inflammation. CD4+Foxp3+T cells play a nonredundant role in the maintenance of intestinal homeostasis through IL-10- and TGF-β-dependent mechanisms. Their activity is complemented by other T and B lymphocytes. Because breakdown in immune regulatory networks in the intestine leads to chronic inflammatory diseases of the gut, such as inflammatory bowel disease and celiac disease, regulatory lymphocytes are an attractive target for therapies of intestinal inflammation.
Cell-Mediated Immune Responses in Tuberculosis
Authors: Cooper Andrea M.
Published: March 2009

Tuberculosis is primarily a disease of the lung, and dissemination of the disease depends on productive infection of this critical organ. Upon aerosol infection with Mycobacterium tuberculosis (Mtb), the acquired cellular immune response is slow to be induced and to be expressed within the lung. This slowness allows infection to become well established; thus, the acquired response is expressed in an inflammatory site that has been initiated and modulated by the bacterium. Mtb has a variety of surface molecules that interact with the innate response, and this interaction along with the autoregulation of the immune response by several mechanisms results in less-than-optimal control of bacterial growth. To improve current vaccine strategies, we must understand the factors that mediate induction, expression, and regulation of the immune response in the lung. We must also determine how to induce both known and novel immunoprotective responses without inducing immunopathologic consequences.
Aire
Authors: Mathis Diane , Benoist Christophe
Published: March 2009

Mutations in the transcriptional regulator, Aire, cause APECED, a polyglandular autoimmune disease with monogenic transmission. Animal models of APECED have revealed that Aire plays an important role in T cell tolerance induction in the thymus, mainly by promoting ectopic expression of a large repertoire of transcripts encoding proteins normally restricted to differentiated organs residing in the periphery. The absence of Aire results in impaired clonal deletion of self-reactive thymocytes, which escape into the periphery and attack a variety of organs. In addition, Aire is a proapoptotic factor, expressed at the final maturation stage of thymic medullary epithelial cells, a function that may promote cross-presentation of the antigens encoded by Aire-induced transcripts in these cells. Transcriptional regulation by Aire is unusual in being very broad, context-dependent, probabilistic, and noisy. Structure/function analyses and identification of its interaction partners suggest that Aire may impact transcription at several levels, including nucleosome displacement during elongation and transcript splicing or other aspects of maturation.
Environmentally Friendly Nickel-Zinc Battery for High Rate Application with Higher Specific Energy
Authors: Phillips Jeff , Mohanta Sam , Geng Mingming , Barton Jeff , McKinney Bryan , Wu James
Published: March 2009

PowerGenix has developed a high-energy density, high-cycle life and low-cost sealed nickel-zinc (NiZn) battery ideal for high discharge rate applications. The technology offers compelling performance advantages over nickel-cadmium and nickel-metal hydride batteries. Most notable is a 30% weight and size reduction coupled with a power density of 2.4 kW/kg.
Single-Cell Injectoassay for ES Cell Engineering
Authors: Matsuoka Hideaki , Saito M.
Published: March 2009

It is important to analyze the intensity dependent action manners of differentiation associated genes in ES cell. For this purpose, single-cell injectoassay was performed by femto-injection method using a single-cell manipulation supporting robot. An Oct3/4 expression vector was introduced into mouse ES cell quantitatively and its effect was evaluated by a cell shape change indicator defined by the perimeter to radius ratio (PR ratio). In the cases of no injection control and the injection control, PR ratio was 7.3-8.0 until 72h. In contrast, when the vector concentration in the injector capillary was 300 ng/micro-L, the rate of differentiation was 33% (2/6). This rate further increased up to 86% (6/7) at 1200 ng/micro-L. These indicate the feasibility of the single-cell injectoassay.
Effects of Corrosion-Resistant Elements on the Corrosion Resistance of Amorphous Bulk Ni-Cr-Mo-Ta-Nb-4P Alloys in Concentrated Hydrochloric Acids
Authors: Shinomiya Hiroyuki , Kato Zenta , Enari Keijiro , Hashimoto Koji
Published: March 2009

Rod-shaped amorphous bulk Ni-Cr-Mo-Ta-Nb-P alloys resistant to concentrated hydrochloric acids were prepared by copper-mold casting. Most of them were spontaneously passive and immune to corrosion in 6 and 12 M HCl. Corrosion resistance was improved remarkably when both chromium and molybdenum were added to the alloy with sufficient tantalum contents. Spontaneous passivation was due to presence of stable air-formed films, in which chromium was particularly concentrated in addition to enrichment of tantalum. The angle resolved XPS revealed that chromium and molybdenum were rich in the inner part of the film. The high corrosion resistance was interpreted in terms of the high stability of the air-formed oxide film consisting of the outer double oxide of chromium and tantalum with a high stability in concentrated hydrochloric acids and the inner molybdenum oxide acting as the diffusion barrier.
Influence of Cooling Rate on Corrosion Resistance of Rapidly Solidified Mg-Zn-Y Alloys with Long Period Stacking Ordered Phase
Authors: Izumi Shogo , Yamasaki Michiaki , Kawamura Yoshihito
Published: March 2009

This paper deals with the influence of cooling rate on the corrosion resistance of rapidly solidified (RS) Mg-Zn-Y alloys with a long period stacking ordered (LPSO) phase. To clarify the effect of microstructure modification by rapid solidification on suppressing localized corrosion such as filiform corrosion, several Mg97.25Zn0.75Y2 (at.%) alloys were prepared with different cooling rates were prepared by the gravity-casting, copper mold injection-casting and melt-spinning techniques. In the alloys solidified at a low cooling rate, filiform corrosion propagated in the early stage of a saltwater immersion test, due to the formation of a massive, block-shaped LPSO phase during casting. In contrast, the alloys solidified at a high cooling rate exhibited excellent corrosion resistance. Rapid solidification brought about grain-refinement and the formation of a supersaturated α-Mg single-phase solid solution, resulting in improved electrochemical homogeneity.
Focused-Ion-Beam-Deposited Pt Contacts on ZnO Nanowires
Authors: He Jr-Hau , Chang Pei H. , Chen Cheng-Ying , Tsai Kun-Tonh
Published: March 2009

We report on the transport properties of single ZnO nanowires measured as a function of the length/square of radius ratio via transmission line method. The specific contact resistance of the FIB Pt contacts to the ZnO nanowires is determined as low as 1.1×10-5 Ωcm2. The resistivity of the ZnO nanowires is measured to be 2.2×10-2 Ωcm. ZnO nanowire-based UV photodetectors contacted by the FIB-Pt with the photoconductive gain as high as ~108 have been fabricated and characterized.
Fine-Tuning of TiO2 Nanofibers-Mixed Nanoparticles-Photoelectrode for High Efficient Dye-Sensitized Solar Cells
Authors: Chuangchote Surawut , Sagawa Takashi , Yoshikawa Susumu
Published: March 2009

Electrospun TiO2 nanofibers were fabricated as a layer of photoelectrode for dye-sensitized solar cells (DSCs). TiO2 nanofibers were fabricated by using sol-gel and electrospinning techniques from mixed solution of titanium butoxide, acetylacetone, and polyvinylpyrrolidone (PVP) in methanol. Calcination of the composite fibers at 450åC for 3 h resulted in predominant content of anatase titania nanofibers. The obtained TiO2 nanofibers showed one-dimensional structure with the diameters about 100-200 nm. These nanofibers were applied to construct the dye (N719) sensitized photoelectrochemical cells with the combination of TiO2 nanoparticles in both original fiber form and nanorods from mechanical grinding of nanofibers. When the TiO2 nanofibers were combined to nanoparticles, enhanced photovoltaic performance was attained as compared with conventional TiO2 nanoparticles. TiO2 nanorods were fabricated by mechanical grinding of electrospun nanofibers and were applied to utilize DSCs. The optimization of thickness of TiO2 nanorods-mixed nanoparticles-photoelectrode was also investigated.
Interfacial Dipole Measurement of Dielectric/Silicon Interface by X-ray Photoelectron Spectroscopy
Authors: Kakushima Kuniyuki , Okamoto Kouichi , Tachi Kiichi , Sato Soushi , Song Jaeyeol , Kawanago Takamasa , Ahmet Parhat , Sugii Nobuyuki , Tsutsui Kazuo , Hattori Takeo , Iwai H.
Published: March 2009

Interfacial dipole presented at the interface of dielectric/silicon has been measured with x-ray photoelectron spectroscopy. With a use of high energy x-ray source, the band bending profile of a silicon substrate and the surface potential can be determined. By comparing the potential profile for p+ and n+-Si wafer, a voltage shift can be calculated. Using this method, a large negative potential shift of 0.5 V at La-silicate/silicon interface has been observed. The obtained value of interfacial dipole is consistent with the value obtained from gate leakage current analysis.
Instability of Chemical Composition in PECVD BPSG film
Authors: Sokolov Yuri V. , Wang Qi
Published: March 2009

A serious concern for borophosphosilicate (BPSG) interlayer is still about film stability in terms of dopant out-diffusion and defect formation. The thermal and compositional instabilities of the PECVD BPSG depend on dopant concentration in the film and on stoichiometry of SiOx matrix. This study addresses the diffusivity of boron and phosphorus through the BPSG and the low temperature oxide (LTO) films. Phosphorus significantly diffuses out of the BPSG film during high temperature densification. The significant boron out-gassing happens in the as-deposited film even at room temperature. This effect depends on the BPSG film composition and whether the LTO film is present or not. The effect is explained based on the change in the charge state in the silicon-oxide interface. The dopant out-diffusion is restricted from the oxygen-rich BPSG film. In addition, the effect of the undoped cap layer on the BPSG is discussed.
The Nonlinear Optical Devices by Using Nano-domain Engineering
Authors: Minakata Makoto , Awano Haruyuki , Ohtsuka Motohiro , Iwata Futoshi , Taniuchi Tetsuo
Published: March 2009

In this paper, we present our recent progress on nano-domain engineering by using the thin-sheet LiNbO3, the improved AFM technique and the electron beam irradiation method. We also demonstrate a newly developed Second Harmonic Generation device and a concept of the large capacity nano-domain memory.
XPS, AES, and Electrochemical Study of Iridium Oxide Coating Materials for Cardiovascular Stent Application
Authors: Atanasoska Liliana , Gupta Pankaj , Deng Charles , Warner R. , Larson Steven , Thompson Julie
Published: March 2009

The surface composition and morphology of iridium oxide (IrO2) coatings prepared by a multi-step physical vapor deposition process on 316L stainless steel stent substrates has been investigated by XPS, AES, and FESEM. The obtained data show that even though the morphologies of iridium oxide films produced within the examined range of PVD process parameters are almost identical, there is a difference in their surface composition, in particular in the ratios of Ir-O σ and Ir=O π bonds. A correlation between the surface stoichiometries of the IrO2 films and their electrochemical CV and EIS responses has been established. The observed differences in the O 1s photoemission line shape of the investigated iridium oxide films were strikingly reflected in their voltammetric curve features. The implication of these finding on the mechanism of the catalytic decomposition of hydrogen peroxide by IrO2 is discussed.
UV-vis Spectroscopy and Cyclic Voltammetry Investigations of Tubular J-Aggregates of Amphiphilic Cyanine Dyes
Authors: Lyon Jennifer L L. , Eisele Doerthe , Kirstein Stefan , Rabe Jürgen P , Vanden Bout David A , Stevenson Keith J.
Published: March 2009

The redox and light absorption properties of immobilized aggregates of the cyanine dye 3,3'-bis(2-sulfopropyl)-5,5',6,6'-tetrachloro-1,1'-dioctylbenzimidacarbocyanine (C8S3) on transparent, conductive indium tin oxide (ITO) electrodes have been studied directly using cyclic voltammetry (CV) in conjunction with UV-vis spectroscopy to elucidate unique mechanistic features of J-aggregate oxidation. C8S3 self-assembles in aqueous solution to form double-walled, tubular J-aggregates with ~13 nm diameter and lengths up to several hundred nanometers. Spectroelectrochemical measurements indicate that irreversible J-aggregate oxidation occurs primarily along the outer wall of the tubular structure as evidenced by the potential-induced irreversible bleaching of J-band absorption. Additionally, J-aggregate oxidation involves both electrochemical and chemical steps in which dimerization and subsequent dehydrogenation of the J-aggregate leads to the formation of a new dehydrogenated dimer oxidation product.
Silicon-Based Novel Bio-Sensing Platforms at the Micro and Nano Scale
Authors: Liu Yaling , Iqbal Samir M.
Published: March 2009

Nanotechnology and BioMEMS will have a significant impact on medicine and biology in the areas of single cell detection, diagnosis and combating disease, providing specificity of drug delivery for therapy, and avoiding time consuming steps to provide faster results and solutions to the patient. Integration of biology and silicon at the micro and nano scale offers tremendous opportunities for solving important problems in biology and medicine and enables a wide range of applications in diagnostics, therapeutics, and tissue engineering. This paper reviews state of the art in silicon-based bioMEMS and bionanotechnology as well as the future challenges and opportunities. A range of silicon devices integrating micro-systems engineering with biology are discussed with focus on rapid detection of biological entities and development of point of care devices using electrical or mechanical phenomena at the micro and nano scale.
Synthesis and Characterization of Nitrogen-doped SnO2 and Comparison to Nitrogen-doped CeO2 Nanoparticles for Visible-light Applications
Authors: Mao Changjie , Zhao Yixin , Qiu Xiaofeng , Zhu Junjie , Burda Clemens
Published: March 2009

Nitrogen-doped SnO2 with varying amounts of nitrogen have been synthesized via a wet-chemical method and compared to CeO2 nanoparticles synthesized under similar conditions. Morphologies, N-doping level, and optical properties were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy (DRS). The N-doped nanoparticles showed enhanced visible-light absorption and photocatalytic activity compared to commercially available TiO2 nanoparticles (Degussa P25). This N-doping process can efficiently modify the physical and chemical properties of metal oxides, which in turn can provide scientists in the field with a promising approach to modify the electronic structure of metal oxides, and thus potentially extend the scope of applications.
Electrolysis of (CH3)4NF•5HF Melt with Boron-doped Diamond Anode
Authors: Shizuno Makoto , Nakanishi Kenta , Inaba Minoru , Uno Masaharu , Nishiki Yoshinori , Furuta Tsuneto , Tasaka Akimasa
Published: March 2009

Since a boron-doped diamond (BDD) electrode is able to be used as an anode in the (CH3)4NF•mHF melt, the performance of BDD anode for electrolytic production of perfluorotrimethylamine [(CF3)3N] was investigated in the melt of (CH3)4NF•5.0HF by galvanostatic electrolysis at 20, 40, 60 and 100 mA•cm−2. The anode gas was analyzed quantatively by gas chromatography-mass spectroscopy. Also, the surface of BDD electrode before and after electrolysis was analyzed by XRD and Raman spectroscopy and was observed by SEM. The ratios of (CF3)3N and (CF3)2CHF2N to overall anode gas increased with increasing the current density. This fact suggests that electrolytic fluorination may be promoted at higher current density. From the results of surface analyses, it is concluded that the electrolytic production of (CF3)3N from (CH3)4NF•5.0HF melt using a BDD anode is an appropriate process because the BDD film on the carbon substrate has a good electric conductivity during electrolysis.
Three-Dimensional Femtosecond Laser Fabrication
Authors: Juodkazis S. , Mizeikis V. , Nishijima Y. , Ebina W. , Misawa H. , Kondo Michio , Švrcek V.
Published: March 2009

We report on the incorporation of silicon nanocrystals (nc-Si) into the photo-polymer resist SU8 by direct laser writing using femtosecond laser pulses and on the holographic formation of nano-/micro-textured surfaces by interference of several beams forming patterns with wide range of spatial frequencies. These approaches open possibility for a three-dimensional (3D) architectures of micro-structures potentially useful for active optical and fluidic micro-devices.
Synthesis and Characterization of YAG:Ce3+ Nanophosphor prepared by Flame Spray Pyrolysis
Authors: Lee Jae Seok , Gupta Sushant , Kumar Purushottam , Ranade Madhav B. , Singh Rajiv K.
Published: March 2009

Among the various types of synthesis techniques for phosphors, flame spray pyrolysis (FSP) is a powerful method which is capable of producing particles with good crystallinity and high luminescence efficiency. In this work, we have studied the possibility of producing yellow light emitting Ce3+ doped Y3Al5O12 (YAG:Ce3+) nanophosphor particles using FSP. The challenges in forming YAG arises is because of its complex stoichiometry and existence of numerous crystalline states. 3 M of urea was added to increase the flame temperature. The as-prepared nanoparticles were annealed in the temperature range 800° to 1100° for 1 hour. As-prepared phosphor particles were found to be YAlO3 which transformed to YAG when annealed above 900°. PL intensity of the phosphors increased with increase in annealing temperature above 900°. These results indicate the possibility of the fabrication of high quality YAG:Ce3+ nanophosphor particles via a simple process.
Luminescence of Y2O3:Eu3+ Nanoparticles Synthesized from Urea Containing Nitrate Based Liquid Precursor by Flame Spray Pyrolysis
Authors: Lee Jae Seok , Kim Taekon , Oh M. H. , Ranade Madhav B. , Singh Rajiv K.
Published: March 2009

Red light emitting Eu3+ doped Y2O3 nanophosphor was prepared by Flame Spray Pyrolysis (FSP) from nitrate based liquid precursors. Different molar percentages of urea were added into the precursor, addition of urea increases the temperature in the flame zone and promotes the formation of nano-size and spherical shaped particles. The importance of urea in the precursor to obtain well dispersed Y2O3:Eu3+ nanophosphor has been studied. The characteristics of nanophosphor such as crystallinity, morphology and photoluminescence in the presence of different moles of urea in nitrate based aqueous solution were investigated. Cubic phase Y2O3:Eu3+ nanophosphor with high crystallinity was obtained directly without any post-heat treatments. Luminescence intensity of nanophosphor increased with the amount of urea till 2 M, further increase in urea concentration was found to reduce the PL intensity. We have developed a continuous single-step fabrication method for nanocrystalline Y2O3:Eu3+ nanophosphor without any post-heat treatments procedure.
A High-luminous Cold Cathode Fluorescent Lamp and Phosphors for a Wide-color-gamut LCD
Authors: Kusunoki Tsuneo , Igarashi Takahiro
Published: March 2009

The two methods to balance the luminance with the wide color-gamut were studied. One is optimizing the combination of phosphors and the other is improving the phosphor efficiency. The new phosphor combination has been introduced into CCFLs. And the new WCG-CCFL has 17% higher luminous efficiency and has better luminance-maintenance characteristics. Co-doping of Tb3+ with Eu3+ improves the luminance-saturation behavior of YVO4:Eu3+.
Development of Bifunctional Carbon Nanotube-Supported Co-Porphyrin Electrocatalytic System for Oxygen Reduction
Authors: Dembinska Beata , Kulesza Pawel J.
Published: March 2009

Combination of multiwalled carbon nanotubes, cobalt porphyrin and tungsten oxide produces a multifunctional electrocatalytic system capable of the effective reduction of oxygen in acid medium. The resulting inks have been utilized during sequential deposition of components. Co-existence of Co-porphyrin, tungsten oxide together with dispersed carbon nanotubes leads to synergistic effect that is evident from positive shift of the oxygen reduction potentials, significant increase of voltammetric currents (relative to those observed at a system not containing carbon nanotube-supported tungsten oxide) and decrease of hydrogen peroxide produced during oxygen reduction. It is reasonable to expect that the reduction of oxygen is initiated at metalloporphyrin redox centers, and the undesirable hydrogen peroxide intermediate is further reduced at partially reduced tungsten oxide. In addition to the methanol tolerance other important issue is the tolerance of the proposed system to ethanol that may appear due to crossover in the cathode compartments of ethanol fuel cells.
Analysis of Threshold Voltage Variations of FinFETs Relating to Short Channel Effects
Authors: Kobayashi Yusuke , Sachid Angada B. , Tsutsui Kazuo , Kakushima Kuniyuki , Ahmet Parhat , Rao V. Ramgopal , Iwai H.
Published: March 2009

Clarification of robustness for threshold voltage (Δth) variation in FinFETs is very important. Vth variation (ΔVth) caused by fluctuations of some principal device parameters are evaluated, compared to the planar MOSFETs. However, the origin of ΔVth is complex in short channel devices due to contribution of short channel effects (SCEs). Therefore, the origin of ΔVth is separated into two factors, that is, intrinsic factor which can be determined by Poisson's equation along M-O-S stack, called the 1D factor, and factors caused by SCEs, called 2D factors. The ΔVth is dominated by both factors on the planar MOSFETs, while it is dominated by the 2D factor on the FinFETs because the amount of spacer charge in the channel is small. Additionally, the Vth is studied in two advanced FinFET structures which show reduced SCEs.
Control of the Crystal Phase in Fe/Si Films by Using Thin Film Zone Melting Crystallization
Authors: Inoue Takeru , Shinsuke Terasawa , Tanaka Yumi , Ihara Manabu
Published: March 2009

For the development of a new solar cell material, b-iron silicide (b-FeS2) films were fabricated by using the following two techniques involving the thin film Zone Melting Crystallization (ZMC) method. First, b-FeSi2 was formed by post-annealing ZMC films composed of a-FeSi2. The phase transition from a-FeSi2 to b-FeSi2 was induced by the post-annealing and promoted with Cu. Second, b-FeSi2 was directly formed from the melt without post-annealing by adjusting the power of upper and lower heaters in the ZMC. Results showed that (1) crystal phase of the Fe/Si films could be controlled by adjusting the power of each heater in the ZMC, (2) Cu promoted formation of b-FeSi2 from amorphous in addition to promoting phase transition from a-FeSi2 to b-FeSi2, and (3) crystal phase of ZMC films depended on the dispersion of Cu in the films.
Charge-Discharge Behavior of Electric Double Layer Capacitor with Acidic Cellulose-Chitin Hybrid Gel Electrolyte
Authors: Yamazaki Shigeaki , Takegawa Akihiko , Kaneko Yoshiro , Kadokawa Jun-ichi , Yamagata Masaki , Ishikawa Masashi
Published: March 2009

A novel acidic cellulose-chitin hybrid gel electrolyte including binary ionic liquids (ILs) with an aqueous H2SO4 solution was prepared for an electric double layer capacitor (EDLC). Its electrochemical characteristics were investigated by galvanostatic charge-discharge measurements. The cell with the hybrid gel containing binary ILs and H2SO4 has higher capacitance than that containing only the aqueous H2SO4 solution. This hybrid gel electrolyte exhibits excellent high-rate discharge capability in a wide range of current densities as well as an aqueous H2SO4 solution. The discharge capacitance of the test cell can retain over 80% of its initial value in 100,000 cycles even at a high current density of 5,000 mA g-1.
Electrochemical Impedance Spectroscopy of PEM Fuel Cell with Metal Bipolar Plates
Authors: Ishibashi Yusuke , Nishikata Atsushi , Tsuru Tooru
Published: March 2009

Proton exchange membrane fuel cell (PEMFC) with metal bipolar plates has many problems for commercial application such as an increase of contact resistance of bipolar plates due to growth of passive film. In this study, electrochemical impedance spectroscopy (EIS) was employed to evaluate PEMFC performance. The EIS of PEMFC was successfully measured and can be explained by simple electrical equivalent circuit. It was found that using impedance at high frequency, the contact resistance can be evaluated.
An Orange-Emitting, Long-Persistent Phosphor, Ca2Si5N8:Eu,Tm
Authors: Miyamoto Yoshinobu , Kato Hikaru , Honna Yuuya , Yamamoto Hajime , Ohmi Koutoku
Published: March 2009

A new orange-emitting, long-persistent phosphor, Ca2Si5N8:Eu2+,Tm3+, was developed. Long afterglow results from electron traps formed by Tm3+ at Ca2+ site. Origin of two main thermoluminescence (TL) glow peaks at 220K and 350K is discussed based on their dependence on Eu or Tm concentration and Ca/Si atomic ratio. Enhancement of TL is observed by excitation in Eu2+ 4f-5d transition at room temperature followed by the fundamental absorption of the host at low temperature.
The Luminescence of Octahedrally Coordinated Divalent Europium in Cs2M2+P2O7(M = Ca, Sr)
Authors: Happek U. , Chaney Stephen , Aycibin Murat , Srivastava Alok
Published: March 2009

In this paper the excitation and emission spectra of Eu2+ in Cs2M2+P2O7, where M2+ = Ca2+ and Sr2+, are presented. The remarkable features of the Eu2+ luminescence in these double phosphate materials include a very large Stokes shift of emission (~1 eV), a high luminescence quenching temperature and a very low energy of the emitted photons, which is unusual for the luminescence of the Eu2+ ion in phosphate based materials. It is shown that the optical spectra can be attributed to an extreme case of the standard Eu2+ 4f65d1→ 4f7[8S7/2] transition.