bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved oral bioavailability of docetaxel by nanostructured lipid carriers: in vitro characteristics, in vivo evaluation and intestinal transport studies
Authors: Fang Guihua , Tang Bo , Chao Yanhui , Zhang Yu , Xu Hui , Tang Xing
Published: November 2015

The objective of the current study was to explore the potential of nanostructured lipid carriers (NLC) for oral delivery of docetaxel (DTX) and investigate the absorption mechanismin vivo.
Imprinted photonic hydrogel pillar for self-reporting water treatment of heavy metal ions
Authors: Yan Yang , Yin Meng , Hong Wei , Xu Zhou , Hu Xiao-Bin
Published: November 2015

In this work we synthesized a self-reporting water absorbent for heavy metal ions by assembling photonic crystals (PC) with imprinted hydrogel pillars.
Dendritic AIE-active luminogens with a POSS core: synthesis, characterization, and application as chemosensors
Authors: Xiang Kai , He Lijuan , Li Yanmin , Xu Caihong , Li Shuhong
Published: November 2015

Two nano-hybrid dendrimers were synthesized by grafting tetraphenylethene units onto a POSS core, and were used as chemosensors for picric acid and Ru3+ ions.
VO2: from negative electrode material to symmetric electrochemical capacitor
Authors: Ma Xue-Jing , Zhang Wei-Bin , Kong Ling-Bin , Luo Yong-Chun , Kang Long
Published: November 2015

A novel negative electrode material of 3D irregular ellipsoidal VO2 with excellent pseudocapacitive properties is synthesized via a simple heat treatment method.
Charge carrier dynamics in Gd–Y co-doped nanocrystalline ceria corroborated with defect interactions
Authors: Anirban Sk. , Dutta Abhigyan
Published: November 2015

Defect cluster formation in nanoceria due to doping.
Synthesis of large CZTSe nanoparticles through a two-step hot-injection method
Authors: Engberg Sara , Li Zhenggang , Lek Jun Yan , Lam Yeng Ming , Schou Jørgen
Published: November 2015

We present an alternative synthesis route to achieve larger Cu2ZnSnSe4 nanoparticles with targeted S/Se-ratios, by introducing selenium in the liquid phase – as liquid selenization!
A multifunctional, plug-and-play and low-cost microfluidic connector system based on electronics standard
Authors: Zhao S. K. , Chen R. , Yu Y. , He L. , Liu J. Q. , Chen X. , Qin S. Y.
Published: November 2015

In this study, we utilized the electrical engineering standard of a 2.54 mm pin-header connector to create two standard microfluidic connectors and two accessories for different applications.
Structures and photoluminescence properties of Alq3 1D materials prepared by an extremely facile solution method
Authors: Xie Wanfeng , Song Hui , Fan Jihui , Jiang Feng , Yuan Huimin , Zhang Shiyu , Wei Zhixian , Pang Zhiyong , Han Shenghao
Published: November 2015

The formation processes of Alq3 rods and the performance of photoluminescence.
Nanocalorimetric platform for accurate thermochemical studies in microliter volumes
Authors: Padovani Rima , Lehnert Thomas , Trouillon Raphaël , Gijs Martin A. M.
Published: November 2015

We present a nanocalorimetric platform for accurate thermochemical studies of (bio-)chemical reactions in a miniaturized format, characterized by fast thermalization time, excellent base temperature stability and fast sensing response time.
Microwave synthesis of carbon nanofibers – the influence of MW irradiation power, time, and the amount of catalyst
Authors: Schwenke Almut M. , Hoeppener Stephanie , Schubert Ulrich S.
Published: November 2015

Carbon nanofibers (CNFs) were synthesized on silicon wafers and graphite microfibers and the influence of the microwave parameters, i.e., irradiation power, and time as well as the amount of applied catalyst, was investigated.
Flower-to-petal structural conversion and enhanced interfacial storage capability of hydrothermally crystallized MnCO3via the in situ mixing of graphene oxide
Authors: Zhao Shiqiang , Feng Fan , Yu Faqi , Shen Qiang
Published: November 2015

The mixing of graphene oxide (GO) induces the flower-to-petal structural conversion of hydrothermally crystallized MnCO3and the resulting spindle–GO composites exhibit an ultrahigh interfacial storage capability for lithium-ion batteries.
La4Ni3O10−δ as an efficient solid oxide fuel cell cathode: electrochemical properties versus microstructure
Authors: Sharma R. K. , Burriel M. , Djurado E.
Published: November 2015

The higher-order Ruddlesden–Popper phase La4Ni3O10−δ is prepared for the first time by electrostatic spray deposition (ESD) on a CGO (Ce0.9Gd0.1O2−δ) electrolyte and evaluated as an intermediate temperature solid oxide fuel cell cathode showing an Rpol value as low as 0.30 Ω cm2 at 700 °C.
Adhering magnetic molecules to surfaces
Authors: Holmberg Rebecca J. , Murugesu Muralee
Published: November 2015

In this review we aim to present an overview of the work that has been performed on attaching and studying Single-Molecule Magnets (SMMs) on various surfaces, with an emphasis on molecular design for surface interaction and on the magnetic properties before and after adhesion occurs.
Yttria-stabilized zirconia microspheres: novel building blocks for high-temperature photonics
Authors: Leib Elisabeth W. , Pasquarelli Robert M. , do Rosário Jefferson J. , Dyachenko Pavel N. , Döring Sebastian , Puchert Anke , Petrov Alexander Yu. , Eich Manfred , Schneider Gerold A. , Janssen Rolf , Weller Horst , Vossmeyer Tobias
Published: November 2015

Yttria-stabilized zirconia microspheres show significantly enhanced thermal stability and are interesting building blocks for IR-reflective photonic glasses operated above 1200 °C.
An apolipoprotein B100 mimotope prevents obesity in mice
Authors: Kim Hyo Joon , Lee Hee Jong , Choi Jung Soon , Han Jemin , Kim Ji Young , Na Hyun Kyun , Joung Hae-Jung , Kim Young Sik , Binas Bert
Published: October 2015

Although apolipoprotein B100 (ApoB100) plays a key role in peripheral fat deposition, it is not considered a suitable therapeutic target in obesity. In the present study we describe a novel ApoB100 mimotope, peptide pB1, and the use of pB1-based vaccine-like formulations (BVFs) against high-fat diet (HFD)-induced obesity. In HFD- compared with chow-fed adolescent mice, BVFs reduced the 3-month body-weight gains attributable to increased dietary fat by 44–65%, and prevented mesenteric fat accumulation and liver steatosis. The body-weight reductions paralleled the titres of pB1-reactive immunoglobulin G (IgG) antibodies, and pB1-reactive antibodies specifically recognized native ApoB100 and a synthetic peptide from the C-terminal half of ApoB100. In cultured 3T3L1 adipocytes, anti-pB1 antibodies increased lipolysis and inhibited low-density lipoprotein (LDL) uptake. In cultured RAW 264.7 macrophages, the same antibodies enhanced LDL uptake (without causing foam cell formation). These findings make ApoB100 a promising target for an immunization strategy against HFD-induced obesity.
On‐chip trimming circuit based on embedded one‐time‐programming memory for magnetic wireless interlayer transmission module
Authors: Chang Liang‐Shun , Shen Kuei‐Hung , Tsai Ming‐Jinn , Lin Chrong‐Jung , King Ya‐Chin
Published: October 2015

A magnetic transmission interface module composed of a high‐sensitivity sensor stacked on top of a micro‐coil is proposed as a contactless connection method for the three‐dimensional integrated circuit. The magnetic sensor responds to the localised magnetic field generated by the signal transmitter, a micro‐coil. To address the variation in response of the corresponding magnetic sensors, two on‐chip trimming circuits incorporating an embedded one‐time‐programming memory are implemented and successfully demonstrated.
Tunable directional coupler for RF front‐end applications
Authors: Solomko V. , Tanc B. , Kehrer D. , Ilkov N. , Bakalski W. , Simbürger W.
Published: October 2015

A tunable directional coupler for radio frequency (RF) front‐ends of handheld mobile devices is presented. The coupler is implemented in a 0.13 μm bulk RF‐CMOS technology with all elements monolithically integrated on a single die. A digitally‐tuned termination network at the isolated port of the coupler is realised solely with RF‐switch transistors using the channel resistance of a metal‐oxide‐semiconductor (MOS) device. The fine‐tuned termination network allows the coupler to achieve a directivity of over 25 dB in the whole cellular frequency range from 699 MHz up to 2.7 GHz. The worst‐case insertion loss in the transmitted path is 0.15 dB at 2.7 GHz.
Acoustical physical constants around room temperature for Ca3TaGa1.5Al1.5Si2O14 single crystal
Authors: Ohashi Y. , Kudo T. , Yokota Y. , Shoji Y. , Kurosawa S. , Kamada K. , Yoshikawa A.
Published: October 2015

A full set of acoustical physical constants was determined for Ca3TaGa1.5Al1.5Si2O14 (CTGAS) single crystal from bulk wave velocities measured by the ultrasonic micro‐spectroscopy method. Several plate specimens were cut perpendicular to the X‐, Y‐, Z‐, 35.25°Y‐, and 139.74°Y‐directions from a CTGAS single crystal ingot grown by Czochralski technique. Following measurements of dielectric constants and density, elastic constants, piezoelectric constants, and their temperature coefficients were determined from longitudinal wave and shear wave velocities measured for the CTGAS specimens at around room temperature. It was demonstrated that the as found constants could provide calculation accuracy within ±0.15% in leaky surface acoustic wave velocity. The determined constants were used for numerical calculation of the cut angle, at which the temperature coefficient of shear wave velocity becomes zero. This angle corresponded to 147.9°Y‐cut substrate that had electromechanical coupling factor of k2 = 3.2%. This parameter is about four times greater than that of AT‐cut α‐quartz.
Use of ultra‐narrow band miniature antennas for internet‐of‐things applications
Authors: Lizzi L. , Ferrero F.
Published: October 2015

The feasibility of using ultra‐narrow band (UNB) antennas for internet‐of‐things applications is discussed. An analysis aimed at evaluating the antenna miniaturisation limits when there are almost no bandwidth requirements is performed. Both numerical and experimental results show that, carefully taking into account the metal conductivity, it is possible to obtain miniature antennas with good impedance matching, UNB, and acceptable efficiency. As a representative example, a wearable on‐body antenna outperforming by 10 dB in terms of total efficiency a commercial solution is presented.
Scale models formulation of switched reluctance generators for low speed energy converters
Authors: Lobato Pedro , Dente Joaquim A. , Martins João F. , Pires Armando J.
Published: October 2015

This study presents a design methodology based on scale models for low speed switched reluctance generators (SRG). This study is motivated by the application of SRG to direct‐drive wind turbines and other low speed renewable energy systems. In direct drive energy converters considerable simplifications result from the elimination of the gear box which has generally been used to interface a slowly rotating shaft with the generator shaft. The comparison and evaluation of magnetic structures plays an important role in the SRG design. General design methodologies are usually oriented towards the evaluation of stator/rotor poles combinations for regular switched reluctance machines. Besides covering that feature, the formulation of scale laws proposed is also suitable to compare other SRG topologies distinguished by different characteristics of electric and magnetic circuits and their own relative position. In addition, this methodology can be extended to other physical phenomena such as thermal changes and magnetic saturation by introducing some constraints. The running example compares a modular short flux‐path topology versus a low speed 20 kW prototype SRG designed for a direct drive wind turbine. The modular topology can optimise the efficiency and weight taking benefits from the significant gain of power per unit of volume and lower losses.
Sliding‐mode position control of medium‐stroke voice coil motor based on system identification observer
Authors: Pan Jianfei , Or Siu Wing , Zou Yu , Cheung Norbert Chow
Published: October 2015

This study presents the performance improvement in the position control of a medium‐stroke voice coil motor (VCM) using a sliding‐mode controller (SMC) with a system identification observer (SIO). The proposed VCM is developed with a full stroke of 24 mm, and its non‐linear electro‐magneto‐mechanical characteristics are analysed by the three‐dimensional finite element method. A least‐squares‐based SIO is introduced into the VCM control system prior to the position regulation of the SMC in order to achieve a shorter rise time of 29 ms and a smaller steady‐state error of <±2 μm under a square‐wave excitation of 20 mm amplitude and 0.5 Hz frequency. An experimental verification between the SMC and a traditional proportion–integral–differential controller is carried out. The results demonstrate improved dynamic and static tracking responses in the SMC under load‐free, frequency‐varying operations.
Direct instantaneous torque control with wide operating range for switched reluctance motors
Authors: Zeng Hui , Chen Hao , Shi Jiaotong
Published: October 2015

Owing to the constraint of the supply voltage, there is a theoretically maximum operating range of the smooth‐torque operation for a switched reluctance drive (SRD). The maximum operating range can be determined by the authors previous work, based on which a novel direct instantaneous torque control (DITC) is proposed for four‐phase 8/6 switched reluctance drive in this study, which can achieve the widest operating range. Compared with the conventional DITC, the proposed DITC does not need the extra optimisation strategy of the switching angle. The performance of the proposed method is identified by simulation and experiment results.
Vortices in two-dimensional nanorings studied by means of the dynamical matrix method
Authors: Mamica S.
Published: October 2015

This paper concerns an investigation of the spin wave excitations in magnetic nanoparticles. We provide a detailed derivation of the theoretical method for the determination of the normal modes of confined magnetic systems based on a discrete lattice of magnetic moments. The method is based on the damping-free Landau–Lifshitz equation and general enough to be utilized for the magnetic system of any dimensionality, magnetic structure, shape, and size. As an example we explore the influence of the competition between exchange and dipolar interactions on the spectrum of normal modes as well as on the stability of the vortex state in two-dimensional nanorings. We show the lowest-frequency mode to be indicative of the dipolar-to-exchange iterations ratio. We also study behavior of the fundamental mode and present the influence of both, the discreteness of the lattice and the dipolar-to-exchange iterations ratio, on its hybridization with azimuthal modes. We complete the paper with a selective review of the spin wave excitations in circular dots to compare with the results obtained for the rings.
Dry patches in a flowing film: Predicting rewetting and the effects of inertia
Authors: Sebilleau Julien , Lebon Luc , Limat Laurent
Published: October 2015

We study the effects of inertia on the shape and stability of dry patches using liquids of decreasing viscosities. These dry patches are formed when a liquid film flows down along a substrate under partial wetting conditions. They become stationary and exhibit an “arch” shape well described by a simple viscous model developed long ago by Podgorski. Surprisingly, this “arch” shape appears to be robust when one decreases the fluid viscosity which increases inertial effects, but the evolution of the apex curvature upon flow rate is strongly affected. We here proposed an improved description of the dry patch evolution taking into account several physical effects as the hydrostatic pressure in the liquid film, the curvature of the contact line, and these inertial effects. These ones affect both the mechanical equilibrium of the rim surrounding the dry patch and the flow inside the rim. This model allows us to show that the dry patch shape remains extremely close to the viscous -Podgorski- prediction but with a rescaling of the apex curvature. It also allows us to get a better prediction of the apex curvature dependence upon flow rate and a prediction of the rewetting threshold above which dry patches are swept away by the film flow. This critical flow rate Γc is in good agreement with our experiments performed in the range of viscosity from 5 to 20 cP with silicon oils.
Strain-mediated deterministic control of 360° domain wall motion in magnetoelastic nanorings
Authors: Liang Cheng-Yen , Sepulveda Abdon E. , Hoff Daniel , Keller Scott M. , Carman Gregory. P.
Published: November 2015

This study provides numerical simulations for deterministic 360° magnetization rotation of the transverse domain walls in a nickel nano-ring (outer diameter: 500 nm, inner diameter: 300 nm, and thickness: 10 nm) on a lead zirconate titanate (Pb[ZrxTi1-x]O3 0 < x < 1) (PZT) thin film (500 nm) deposited onto a Si substrate with surface patterned electrodes. Two alternative electrode architectures are studied, namely, a 4-electrode and a 6-electrode configuration. The 4-electrode configuration relies on magnetization dynamics to produce an overshoot coupled with proper timing control of the voltage applied to achieve 360° magnetization rotation. In contrast, the 6-electrode configuration only requires sequential voltage application to successive pairs of electrodes and thus can be operated at quasi-static speeds and does not rely on magnetization dynamics to achieve 360° magnetization rotation. These analytical models provide support for developing new devices such as nanoscale multiferroic driven electromagnetic motors.
Kapitza resistance and the thermal conductivity of amorphous superlattices
Authors: Giri Ashutosh , Hopkins Patrick E. , Wessel James G. , Duda John C.
Published: November 2015

We report on the thermal conductivities of amorphous Stillinger-Weber and Lennard-Jones superlattices as determined by non-equilibrium molecular dynamics simulations. Thermal conductivities decrease with increasing interface density, demonstrating that interfaces contribute a non-negligible thermal resistance. Interestingly, Kapitza resistances at interfaces between amorphous materials are lower than those at interfaces between the corresponding crystalline materials. We find that Kapitza resistances within the Stillinger-Webber based Si/Ge amorphous superlattices are not a function of interface density, counter to what has been observed in crystalline superlattices. Furthermore, the widely used thermal circuit model is able to correctly predict the interfacial resistance within the Stillinger-Weber based amorphous superlattices. However, we show that the applicability of this widely used thermal circuit model is invalid for Lennard-Jones based amorphous superlattices, suggesting that the assumptions made in the model do not hold for these systems.
Photoluminescence probing of interface evolution with annealing in InGa(N)As/GaAs single quantum wells
Authors: Shao Jun , Qi Zhen , Zhao H. , Zhu Liang , Song Yuxin , Chen Xiren , Zha F.-X. , Guo Shaoling , Wang S. M.
Published: November 2015

The effects of thermal annealing on the interfaces of InGa(N)As/GaAs single quantum wells (SQWs) are investigated by excitation-, temperature-, and magnetic field-dependent photoluminescence (PL). The annealing at 750 °C results in more significant blueshift and narrowing to the PL peak than that at 600 °C. Each of the PL spectra can be reproduced with two PL components: (i) the low-energy component (LE) keeps energetically unchanged, while the high-energy component (HE) moves up with excitation and shows at higher energy for the In0.375Ga0.625As/GaAs but crosses over with the LE at a medium excitation power for the In0.375Ga0.625N0.012As0.988/GaAs SQWs. The HE is broader than the corresponding LE, the annealing at 750 °C narrows the LE and HE and shrinks their energetic separation; (ii) the PL components are excitonic, and the InGaNAs shows slightly enhanced excitonic effects relative to the InGaAs SQW; (iii) no typical S-shape evolution of PL energy with temperature is detectable, and similar blueshift and narrowing are identified for the same annealing. The phenomena are mainly from the interfacial processes. Annealing improves the intralayer quality, enhances the interfacial In-Ga interdiffusion, and reduces the interfacial fluctuation. The interfacial interdiffusion does not change obviously by the small N content and hence similar PL-component narrowing and blueshift are observed for the SQWs after a nominally identical annealing. Comparison with previous studies is made and the PL measurements under different conditions are shown to be effective for probing the interfacial evolution in QWs.
Band alignment of atomic layer deposited (HfZrO4)1−x(SiO2)x gate dielectrics on Si (100)
Authors: Heo Sung , Tahir Dahlang , Chung Jae Gwan , Lee Jae Cheol , Kim KiHong , Lee Junho , Lee Hyung-Ik , Park Gyeong Su , Oh Suhk Kun , Kang Hee Jae , Choi Pyungho , Choi Byoung-Deog
Published: November 2015

The band alignment of atomic layer deposited (HfZrO4)1−x(SiO2)x (x = 0, 0.10, 0.15, and 0.20) gate dielectric thin films grown on Si (100) was obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence band offset, and conduction band offset values for HfZrO4 silicate increased from 5.4 eV to 5.8 eV, from 2.5 eV to 2.75 eV, and from 1.78 eV to 1.93 eV, respectively, as the mole fraction (x) of SiO2 increased from 0.1 to 0.2. This increase in the conduction band and valence band offsets, as a function of increasing SiO2 mole fraction, decreased the gate leakage current density. As a result, HfZrO4 silicate thin films were found to be better for advanced gate stack applications because they had adequate band gaps to ensure sufficient conduction band offsets and valence band offsets to Si.
The analysis of Raman scattering in a free-electron laser with a rectangular hybrid wiggler
Authors: Kordbacheh A. , Shahsavand M.
Published: October 2015

A one dimensional theory of the stimulated Raman backscattering process in a free electron laser with rectangular hybrid wiggler (RHW) is analyzed. The dispersion relation in the rest frame of the electron beam and also a formula for the lab-frame spatial growth rate are derived. A numerical computation of the growth rate for RHW is conducted and a comparison with that for coaxial hybrid wiggler is made away from the resonance. The growth rate is found larger for the rectangular wiggler than for the coaxial wiggler. A much narrower magnetoresonance associated with the third spatial harmonic is also obtained compared to the first one.
Double-peaked edge-bead in drying film of solvent-resin mixtures
Authors: Shiratori Suguru , Kubokawa Toru
Published: October 2015

A thick ridge of a film arising along the periphery of a substrate, which is the so-called edge-bead, is investigated experimentally and numerically for the case where the bead becomes double-peaked shape in direction away from the periphery of the substrate. It is clarified, by the optical measurement of thickness variations, that the double-peaked bead is separated from a single bead during the drying process, and after the separation, the inner bead moves inward. This motion of the bead is modeled by a lubrication-approximated flow equation, where the Laplace pressure and the solutocapillary effect are taken into account, coupled with the convective and diffusive mass transfer. The numerically simulated motion of the bead shows a good agreement with that obtained by the experiment, and it is revealed that the mechanism how the double-peaked edge-bead is formed. At the early stage of the drying process, a single bead is formed by the Laplace pressure due to the curvature along the substrate periphery. Along this single bead, the concentration gradient is caused by both the spatial distribution of the evaporation rate and the thickness effect on the change rate of the concentration, due to the fact that the resin concentration increases at a faster rate in the thin region. Consequently, the concentration distribution has a local minimum in the middle of the single bead, which drives oppositely directed solutocapillary flows and separates the bead. After the separation, the inner bead moves inward by a kind of a feed-forward mechanism, until the viscosity of the film becomes large enough to suppress the flow.
Multi-state and non-volatile control of graphene conductivity with surface electric fields
Authors: Iurchuk V. , Majjad H. , Chevrier F. , Kundys D. , Leconte B. , Doudin B. , Kundys B.
Published: November 2015

Planar electrodes patterned on a ferroelectric substrate are shown to provide lateral control of the conductive state of a two-terminal graphene stripe. A multi-level and on-demand memory control of the graphene resistance state is demonstrated under low sub-coercive electric fields, with a susceptibility exceeding by more than two orders of magnitude those reported in a vertical gating geometry. Our example of reversible and low-power lateral control over 11 memory states in the graphene conductivity illustrates the possibility of multimemory and multifunctional applications, as top and bottom inputs remain accessible.
H4: A challenging system for natural orbital functional approximations
Authors: Ramos-Cordoba Eloy , Lopez Xabier , Piris Mario , Matito Eduard
Published: October 2015

The correct description of nondynamic correlation by electronic structure methods not belonging to the multireference family is a challenging issue. The transition of D2h to D4h symmetry in H4 molecule is among the most simple archetypal examples to illustrate the consequences of missing nondynamic correlation effects. The resurgence of interest in density matrix functional methods has brought several new methods including the family of Piris Natural Orbital Functionals (PNOF). In this work, we compare PNOF5 and PNOF6, which include nondynamic electron correlation effects to some extent, with other standard ab initio methods in the H4 D4h/D2h potential energy surface (PES). Thus far, the wrongful behavior of single-reference methods at the D2h–D4h transition of H4 has been attributed to wrong account of nondynamic correlation effects, whereas in geminal-based approaches, it has been assigned to a wrong coupling of spins and the localized nature of the orbitals. We will show that actually interpair nondynamic correlation is the key to a cusp-free qualitatively correct description of H4 PES. By introducing interpair nondynamic correlation, PNOF6 is shown to avoid cusps and provide the correct smooth PES features at distances close to the equilibrium, total and local spin properties along with the correct electron delocalization, as reflected by natural orbitals and multicenter delocalization indices.
A one-dimensional ion beam figuring system for x-ray mirror fabrication
Authors: Idir Mourad , Huang Lei , Bouet Nathalie , Kaznatcheev Konstantine , Vescovi Matthew , Lauer Ken , Conley Ray , Rennie Kent , Kahn Jim , Nethery Richard , Zhou Lin
Published: October 2015

We report on the development of a one-dimensional Ion Beam Figuring (IBF) system for x-ray mirror polishing. Ion beam figuring provides a highly deterministic method for the final precision figuring of optical components with advantages over conventional methods. The system is based on a state of the art sputtering deposition system outfitted with a gridded radio frequency inductive coupled plasma ion beam source equipped with ion optics and dedicated slit developed specifically for this application. The production of an IBF system able to produce an elongated removal function rather than circular is presented in this paper, where we describe in detail the technical aspect and present the first obtained results.
The Shannon’s mutual information of a multiple antenna time and frequency dependent channel: An ergodic operator approach
Authors: Hachem Walid , Moustakas Aris , Pastur Leonid A.
Published: November 2015

Consider a random non-centered multiple antenna radio transmission channel. Assume that the deterministic part of the channel is itself frequency selective and that the random multipath part is represented by an ergodic stationary vector process. In the Hilbert space l2(ℤ), one can associate to this channel a random ergodic self-adjoint operator having a so-called Integrated Density of States (IDS). Shannon’s mutual information per receive antenna of this channel coincides then with the integral of a log function with respect to the IDS. In this paper, it is shown that when the numbers of antennas at the transmitter and at the receiver tend to infinity at the same rate, the mutual information per receive antenna tends to a quantity that can be identified and, in fact, is closely related to that obtained within the random matrix approach [I. Telatar, Eur. Trans. Telecommun. 10, 585 (1999)]. This result can be obtained by analyzing the behavior of the Stieltjes transform of the IDS in the regime of the large numbers of antennas.
0.42 TW 2-cycle pulses at 1.8 μm via hollow-core fiber compression
Authors: Cardin Vincent , Thiré Nicolas , Beaulieu Samuel , Wanie Vincent , Légaré François , Schmidt Bruno E.
Published: November 2015

By employing pulse compression with a stretched hollow-core fiber, we generated 2-cycle pulses at 1.8 μm (12 fs) carrying 5 mJ of pulse energy at 100 Hz repetition rate. This energy scaling in the mid-infrared spectral range was achieved by lowering the intensity in a loose focusing condition, thus suppressing the ionization induced losses. The correspondingly large focus was coupled into a hollow-core fiber of 1 mm inner diameter, operated with a pressure gradient to further reduce detrimental nonlinear effects. The required amount of self-phase modulation for spectral broadening was obtained over 3 m of propagation distance.
Elimination of carbon vacancies in 4H-SiC epi-layers by near-surface ion implantation: Influence of the ion species
Authors: Ayedh H. M. , Hallén A. , Svensson B. G.
Published: November 2015

The carbon vacancy (VC) is a prevailing point defect in high-purity 4H-SiC epitaxial layers, and it plays a decisive role in controlling the charge carrier lifetime. One concept of reducing the VC-concentration is based on carbon self-ion implantation in a near surface layer followed by thermal annealing. This leads to injection of carbon interstitials (Ci's) and annihilation of VC's in the epi-layer “bulk”. Here, we show that the excess of C atoms introduced by the self-ion implantation plays a negligible role in the VC annihilation. Actually, employing normalized implantation conditions with respect to displaced C atoms, other heavier ions like Al and Si are found to be more efficient in annihilating VC's. Concentrations of VC below ∼2 × 1011 cm−3 can be reached already after annealing at 1400 °C, as monitored by deep-level transient spectroscopy. This corresponds to a reduction in the VC-concentration by about a factor of 40 relative to the as-grown state of the epi-layers studied. The negligible role of the implanted species itself can be understood from simulation results showing that the concentration of displaced C atoms exceeds the concentration of implanted species by two to three orders of magnitude. The higher efficiency for Al and Si ions is attributed to the generation of collision cascades with a sufficiently high energy density to promote Ci-clustering and reduce dynamic defect annealing. These Ci-related clusters will subsequently dissolve during the post-implant annealing giving rise to enhanced Ci injection. However, at annealing temperatures above 1500 °C, thermodynamic equilibrium conditions start to apply for the VC-concentration, which limit the net effect of the Ci injection, and a competition between the two processes occurs.
Abnormal cubic-tetragonal phase transition of barium strontium titanate nanoparticles studied by in situ Raman spectroscopy and transmission electron microscopy heating experiments
Authors: Zhang Yin , Chen Chen , Gao Ran , Xia Feng , Li YueSheng , Che Renchao
Published: November 2015

Phase stability of the ferroelectric materials at high temperature is extremely important to their device performance. BaxSr1−xTiO3 (BST) nanoparticles with different Sr contents (x = 1, 0.91, 0.65, 0.4, and 0) are prepared by a facile hydrothermal method. Using Raman spectroscopy and transmission electron microscopy (TEM) analyses under in situ heating conditions (up to 300 °C), the phase transitions of BST nanoparticles between 25 °C and 280 °C are comprehensively investigated. The original Curie temperature of BST nanoparticles decreases abruptly with the increase in Sr content, which is more obvious than in the bulk or film material. Besides, an abnormal phase transition from cubic to tetragonal structure is observed from BST nanoparticles and the transition temperature rises along with the increase in Sr content. Direct TEM evidences including a slight lattice distortion have been provided. Differently, BaTiO3 nanoparticles remained in the tetragonal phase during the above temperature ranges.
Cyclic evolution of the electron temperature and density in dusty low-pressure radio frequency plasmas with pulsed injection of hexamethyldisiloxane
Authors: Garofano V. , Stafford L. , Despax B. , Clergereaux R. , Makasheva K.
Published: November 2015

Optical emission spectroscopy was used to analyze the very-low-frequency cyclic evolution of the electron energy and density caused by repetitive formation and loss of dust nanoparticles in argon plasmas with pulsed injection of hexamethyldisiloxane (HMDSO, [CH3]6Si2O). After elaborating a Boltzmann diagram for Ar high-lying levels and a collisional-radiative model for Ar 2p (Paschen notation) states, temperatures characterizing the low- and high-energy parts of the electron population were calculated. Relative electron densities were also estimated from relative line emission intensities. Both temperatures increase when the dust occupation increases, and then decrease when dust is lost. The opposite trend was observed for the electron density. Such cyclic behaviors of the electron energy and electron density in the HMDSO-containing plasmas are in good agreement with the evolution processes in dusty plasmas, in which the formation of negative ions followed by an electron attachment on the surfaces of the nanoparticles is a critical phenomenon driving dust growth.
Polarization-resolved cartography of light emission of a vertical-cavity surface-emitting laser with high space and frequency resolution
Authors: Wang T. , Lippi G. L.
Published: November 2015

We couple a double-channel imaging technique, allowing for the simultaneous acquisition of high-quality and high-resolution intensity and peak emission wavelength profiles [T. Wang and G. L. Lippi, Rev. Sci. Instrum. 86, 063111 (2015)], to the polarization-resolved analysis of the optical emission of a multimode vertical-cavity surface-emitting laser (VCSEL). Detailed information on the local wavelength shifts between the two polarized components and on the wavelength gradients can be easily gathered. A polarization- and position-resolved energy balance can be constructed for each wavelength component, allowing in a simple way for a direct analysis of the collected light. Applications to samples, other than VCSELs, are suggested.
Study on limiting efficiencies of a-Si:H/μc-Si:H-based single-nanowire solar cells under single and tandem junction configurations
Authors: Zhai Xiongfei , Cao Guoyang , Wu Shaolong , Shang Aixue , Li Xiaofeng
Published: November 2015

Detailed balance calculations are presented for a-Si:H/μc-Si:H-based single- and tandem-junction single-nanowire solar cells (S- and T-SNSCs). Our study is based on three-dimensional finite-element electromagnetic simulation and thermodynamic balanced analysis, which includes radiative and Auger recombinations simultaneously. We quantify and compare the limiting short-circuit current densities, open-circuit voltages, and light-conversion efficiencies of these highly compact photovoltaic cells, addressing especially the effect of Auger recombination on the open-circuit voltages of SNSCs. Results show that tandem design leads to much higher light-conversion capability than μc-Si:H S-SNSCs, but exhibits superior performance than a-Si:H S-SNSCs only for cells with large radii.
Magnetic field-modulated photo-thermo-electric effect in Fe/GaAs film
Authors: Qiao Shuang , Liu Jihong , Yan Guoying , Zhao Jianhua , Zhang Xinhui , Wang Shufang , Fu Guangsheng
Published: November 2015

Ferromagnet/semiconductor heterostructure, such as Fe/GaAs, is always one of the key issues in spintronics due to its prerequisite for the realization of spin sensitive devices. In this letter, a lateral photoelectric effect (LPE) was observed in Fe/GaAs. Our results show that the sensitivity was not related to laser wavelength, but only proportional to laser power, suggesting that the lateral photovoltage was induced by photo-thermo-electric effect. Moreover, we also observe that the voltage signal increases with the increase in applied field due to decreasing scattering probability for spin-polarized electrons. Our finding of LPE adds another functionality to the Fe/GaAs system and will be useful in development of spin-polarized voltage devices.
Optical pulse generation in a transistor laser via intra-cavity photon-assisted tunneling and excess base carrier redistribution
Authors: Feng M. , Iverson E. W. , Wang C. Y. , Holonyak N.
Published: November 2015

For a direct-gap semiconductor (e.g., a p-n junction), photon-assisted tunneling is known to exhibit a high nonlinear absorption. In a transistor laser, as discussed here, the coherent photons generated at the quantum well interact with the collector junction field and “assist” electron tunneling from base to collector, thus resulting in the nonlinear modulation of the laser and the realization of optical pulse generation. 1 and 2 GHz optical pulses are demonstrated in the transistor laser using collector voltage control.
Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells
Authors: Kim Hyo-Joong , Lee Hyun Hwi , Kal Jinha , Hahn Jungseok , Kim Han-Ki
Published: October 2015

The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.
Topotactic synthesis of strontium cobalt oxyhydride thin film with perovskite structure
Authors: Katayama Tsukasa , Chikamatsu Akira , Kamisaka Hideyuki , Yokoyama Yuichi , Hirata Yasuyuki , Wadati Hiroki , Fukumura Tomoteru , Hasegawa Tetsuya
Published: October 2015

The substitution of hydride anions (H−) into transition metal oxides has recently become possible through topotactic reactions or high-pressure synthesis methods. However, the fabrication of oxyhydrides is still difficult because of their inherently less-stable frameworks. In this study, we successfully fabricated perovskite SrCoOxHy thin films via the topotactic hydride doping of brownmillerite SrCoO2.5 epitaxial thin films with CaH2. The perovskite-type cation framework was maintained during the topotactic treatment owing to epitaxial stabilization. Structural and chemical analyses accompanied by X-ray absorption spectroscopy measurements revealed that the doped hydride ions form a two-dimensional network of Co-H−-Co bonds, in contrast to other reported perovskite oxyhydrides, SrMO3−xHx (M = Cr, Ti, V). The SrCoOxHy thin film exhibited insulating behavior and had a direct band gap of 2.1 eV. Thus, topotactic hydride doping of transition-metal-oxide thin films on suitable substrates is a promising method for the synthesis of new transition metal oxyhydrides.
An extraordinary transmission analogue for enhancing microwave antenna performance
Authors: Pushpakaran Sarin V. , Purushothaman Jayakrishnan M. , Chandroth Aanandan , Pezholil Mohanan , Kesavath Vasudevan
Published: October 2015

The theory of diffraction limit proposed by H.A Bethe limits the total power transfer through a subwavelength hole. Researchers all over the world have gone through different techniques for boosting the transmission through subwavelength holes resulting in the Extraordinary Transmission (EOT) behavior. We examine computationally and experimentally the concept of EOT nature in the microwave range for enhancing radiation performance of a stacked dipole antenna working in the S band. It is shown that the front to back ratio of the antenna is considerably enhanced without affecting the impedance matching performance of the design. The computational analysis based on Finite Difference Time Domain (FDTD) method reveals that the excitation of Fabry-Perot resonant modes on the slots is responsible for performance enhancement.
Rational molecular dynamics scheme for predicting optimum concentration loading of nano-additive in phase change materials
Authors: Rastogi Monisha , Vaish Rahul , Madhar Niyaz Ahamad , Shaikh Hamid , Al-Zahrani S. M.
Published: October 2015

The present study deals with the diffusion and phase transition behaviour of paraffin reinforced with carbon nano-additives namely graphene oxide (GO) and surface functionalized single walled carbon nanotubes (SWCNT). Bulk disordered systems of paraffin hydrocarbons impregnated with carbon nano-additives have been generated in realistic equilibrium conformations for potential application as latent heat storage systems. Ab initio molecular dynamics(MD) in conjugation with COMPASS forcefield has been implemented using periodic boundary conditions. The proposed scheme allows determination of optimum nano-additive loading for improving thermo-physical properties through analysis of mass, thermal and transport properties; and assists in determination of composite behaviour and related performance from microscopic point of view. It was observed that nanocomposites containing 7.8 % surface functionalised SWCNT and 55% GO loading corresponds to best latent heat storage system. The propounded methodology could serve as a by-pass route for economically taxing and iterative experimental procedures required to attain the optimum composition for best performance. The results also hint at the large unexplored potential of ab-initio classical MD techniques for predicting performance of new nanocomposites for potential phase change material applications.
High thermal stability of the amorphous oxide in Ti44.5Cu44.5Zr7Be4 metallic glass
Authors: Park Sung Hyun , Lim Ka Ram , Na Min Young , Kim Kang Cheol , Kim Won Tae , Kim Do Hyang
Published: November 2015

The oxidation behavior of Ti44.5Cu44.5Zr7Be4 metallic glass has been investigated. The oxide layer with a fully amorphous structure forms when heated up to the SCL temperature region, indicating that the presence of Be in the oxide layer improves the thermal stability of the amorphous oxide. The amorphous oxide is stable even when heated above the crystallization onset temperature. The thickness of the amorphous oxide layer reaches to ∼160 nm when heated up to 773 K. The oxide layer grows in both inward and outward directions, leaving Cu-enriched crystalline particles at the middle section of the oxide layer.
Nano magnetic vortex wall guide
Authors: Yuan H. Y. , Wang X. R.
Published: November 2015

A concept of nano magnetic vortex wall guide is introduced. Two architectures are proposed. The first one is properly designed superlattices while the other one is bilayer nanostrips. The concept is verified by micromagnetic simulations. Both guides can prevent the vortex core in a magnetic vortex wall from colliding with sample surface so that the information stored in the vortex core can be preserved during its transportation from one location to another one through the guides.
Influence of electrode groove geometry on the passive control of the depletion layer in microfluidic fuel cells
Authors: Lee Seung-Wu , Ahn Yoomin
Published: November 2015

Mitigation of the concentration boundary layer is an essential requirement to improve the power density of microfluidic fuel cells. In this study, the formation of a groove shape in the surface of the electrodes, located in parallel on the bottom of the channel, is proposed for the passive control of the depletion layer. The flow field inside the channel is numerically simulated and cell performance is experimentally measured for the various groove formation patterns (converging, parallel, or diverging) and tilt angles (30, 45, or 60°). Experimentally measured cell performance also shows superior results at the best conditions as determined by numerical modeling, where the interdiffusion zone at the fuel-oxidant interface is not significantly expanded and the flow in the direction normal to the electrode surface is large. Our results show that the depletion region is well-controlled when the groove angle is large and when the groove pattern is not parallel, due to the increase in chaotic mixing. At these conditions, with formic acid as the fuel and a platinum electrode, the maximum current density and peak power density are increased by 38.42% and 38.09%, respectively, compared to the values for flat electrodes. Even better cell performance is expected if the optimum design of the groove shape is determined using flow analysis.
Two-pass alignment improves novel splice junction quantification
Authors: Veeneman Brendan A. , Shukla Sudhanshu , Dhanasekaran Saravana M. , Chinnaiyan Arul M. , Nesvizhskii Alexey I.
Published: October 2015

Motivation: Discovery of novel splicing from RNA sequence data remains a critical and exciting focus of transcriptomics, but reduced alignment power impedes expression quantification of novel splice junctions.

Results: Here, we profile performance characteristics of two-pass alignment, which separates splice junction discovery from quantification. Per sample, across a variety of transcriptome sequencing datasets, two-pass alignment improved quantification of at least 94% of simulated novel splice junctions, and provided as much as 1.7-fold deeper median read depth over those splice junctions. We further demonstrate that two-pass alignment works by increasing alignment of reads to splice junctions by short lengths, and that potential alignment errors are readily identifiable by simple classification. Taken together, two-pass alignment promises to advance quantification and discovery of novel splicing events.

Contact:  arul@med.umich.edu, nesvi@med.umich.edu

Availability and implementation: Two-pass alignment was implemented here as sequential alignment, genome indexing, and re-alignment steps with STAR. Full parameters are provided in Supplementary Table 2.

Supplementary information:  Supplementary data are available at Bioinformatics online.