bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Positron Annihilation Spectroscopy on Open-Volume Defects in Group IV Semiconductors
Authors: Slotte Jonatan , Tuomisto Filip , Kujala Jiri , Holm Andreas M. , Segercrantz Natalie , Kilpeläinen Simo , Kuitunen Katja , Simoen Eddy , Gencarelli Federica , Loo R , Shimura Yosuke
Published: September 2014

In this review of recent results from the positron group at Aalto university, we show how positron annihilation spectroscopy (PAS) can be used for identifying and studying the stability of open volume defects in different Si, Ge and SiGe structures. Some preliminary new results on GeSn are also presented. We show how the electronic states of the E center in SiGe have been determined as well as how thermal stability of this defect can be studied with PAS. In Ge we identify the monovacancy and the divacancy and study their thermal stability. PAS can also be used for studying interface states and this is utilized on Si nanoparticles embedded in SiO2.
(Invited) Synchrotron Radiation Based X-ray Microdiffraction of Advanced Semiconductor Materials
Authors: Sakai Akira
Published: September 2014

Synchrotron-radiation-based X-ray microdiffraction (XRMD) measurements were employed as a new powerful method to characterize several kinds of advanced semiconductor epitaxial films. The XRMD with a few hundred nanometer beam size effectively reveals crystal domain textures and microscopic residual strain distribution in the films, which is respectively demonstrated for Ge thin lines with nanometer scale widths formed by the aspect ratio epitaxy and thick AlN films grown on the trench-patterned AlN/α-Al2O3 templates. Based on the XRMD results, the origin of the domain texturing in the thin Ge lines and the influence of nanometer-scale periodically-aligned voids in the AlN films on the strain distribution are discussed.
(Invited) Single Dislocations as Nanostructure Devices: Physics and Applications
Authors: Reiche Manfred , Kittler Martin , Uebensee Hartmut , Pippel Eckhard , Erfurth Winfried
Published: September 2014

Dislocations are one-dimensional crystal defects. Their dimension characterize the defects as nanostructures (nanowires). Measurements on defined dislocation arrays proved numerous exceptional electronic and optical properties. A model of dislocations as quantum wires is proposed. The formation of the quantum wire is a consequence of the high strain level on the dislocation core modifying locally the band structure. Potential applications of defined dislocation arrays in devices are discussed.
Temperature Dependent Young's Modulus of Si and Ge
Authors: Vanhellemont Jan , Swarnakar Akhilesh Kumar , Van der Biest Omer
Published: September 2014

The vibrational properties of single crystal Si and Ge are studied between room and melting temperature T

m
using the impulse excitation technique. From the measurements, the temperature dependent Young’s moduli E

are extracted in the <100>-, <110>- and <111>- directions. For both semiconductors, the Young’s moduli decrease smoothly with increasing temperature and retain high values up to T

m
. Using the semi-empiric Wachtman's equation allows an excellent fit to the experimental data for the temperature dependence of E

<100>
, E

<110>
and E

<111>
between room temperature and 0.6T

m
,. For higher temperatures, the Young's moduli decrease faster than predicted by Wachtman's equation. In the case of Ge, an apparent enhanced softening is observed starting from about 850 ºC which is due to a loss of Ge material, leading to a decrease of sample dimensions and weight.
(Invited) Electron Flow in GC8 DNA Strand
Authors: Qi Jianqing , Anantram M. P.
Published: September 2014

In this work, we study the electron flow through an eight-base pair DNA heterostructure GC8. Using Landauer-Buttiker formula, we analyze the effects of three factors, decoherence, thiol-group and two different electron injection methods (inter-strand transport and intra-strand transport). The results show that decoherence due to electron’s interaction with environment is important in charge transport through DNA heterostructures and crucial in getting conductance values close to the experiment. We also find that the thiol-group is highly insulating by investigating the transmission and conductance of the strand with two injection approaches- via base and via sulfur atom in the linker group. Comparison of inter-strand and intra-strand transport near the highest occupied molecular orbital level is also discussed.
Effects of Doping, Strain and Size on the Electrical Properties of MoS2 Nanoribbons
Authors: Yu Sheng , Li Qiliang , Eshun Kwesi
Published: September 2014

In this work, we have investigated size, doping and strain effect on the electrical properties of n-type and p-type MoS2 monolayer, one of the most interesting two-dimensional layered materials. We found that the bandgap of the MoS2 will reduce from 1.8 eV to 1.2 eV as the infinite lattice being shrunk into 10×10 nanoribbon. The electrical properties of a nanoscale MoS2 monolayer exhibited large variation (≈ 20%) as its doping level or dopant position changes, although the band-gap varies slightly. The study on the strain effect indicates that the bandgap of infinite MoS2 monolayer monotonically reduces as the increasing of the strain strength. The variation in electrical properties induced by size, doping and strain effect may post a serious challenge on the application in logic and memory devices.
Pd/TiO2-Multiwall Nanotubes toward Electrocatalytic Oxidation of Formic Acid in Acid Media
Authors: Aldana-González Jorge , Montes de Oca Maria Guadalupe , Olvera Juan Carlos , Sánchez-Guajardo Rebeca , Garfias-García Elizabeth , Romero-Romo Mario Alberto , Palomar-Pardavé Manuel
Published: September 2014

This work reports the electro-oxidation of formic acid using Pd as catalyst supported on third generation TiO2 nanotubes. The results indicate that it is possible to carry out the electro-oxidation of formic acid in acidic medium, and shows an increase in the oxidation of formic acid, by increasing the Pd electrodeposition time on TiO2NTBs.
Electrokinetic Trapping and Patterning of Colloidal Particles in Asymmetric Ratchet Microchannels
Authors: Kale Akshay , Lu Xinyu , Patel Saurin , Xuan Xiangchun
Published: September 2014

Insulator-based dielectrophoresis offers advantages over electrode-based dielectrophoresis in many ways, and has been extensively used to manipulate, sort and selectively trap particles and biological species in Lab-on-a-chip devices. This work exploits insulator-based dielectrophoresis in two configurations of asymmetric ratchet microchannels to trap microscale particles using DC biased AC voltages. It demonstrates for that dynamics of the DEP trapping zones changes in response to voltages higher than the threshold trapping voltages, and also with longer experimental runtimes. Numerical modeling is used to support and validate the results, and the physical interpretations of the changing DEP are explained using a dimensionless trapping number. With the help of the microchannel configurations, it is revealed that the orientation of the asymmetric ratchet relative to the direction of DC electric field plays a key role in determining the trapping patterns
(Keynote) Atomic Scale and Interface Interactions in Redox-Based Resistive Switching Memories
Authors: Valov Ilia , Tappertzhofen Stefan , Linn Eike , Menzel Stephan , van den Hurk Jan , Waser Rainer
Published: September 2014

Controlling electrochemical processes at interfaces or within thin films at the atomic scale is a key factor for further development of future nanoelectronics and information technology. This aspect becomes even more important considering concepts beyond conventional data storage like neuromorphic and memristive systems, demonstrating learning abilities and allowing logic operations. In redox-based resistive switching memories (ReRAMs), the solid electrolyte thickness varies in the range between few nanometers up to some ten nanometers. Due to the small dimensions, the high electric fields in the order of E ~ 108 Vm–1, and current densities of j ~ 109 Acm–2, the interface regions are dynamically changing as a function of the thermodynamic and operation conditions. The paper presents an overview on the current state-of-the-art knowledge on atomically scaled processes and interactions, focusing on the electrochemical dynamics at the metal/solid-electrolyte interfaces of nanoscaled thin films and quantum effects.
(Invited) Elucidating the Origin of Resistive Switching in Ultrathin Hafnium Oxides through High Spatial Resolution Tools
Authors: Shi Yuanyuan , Ji Yanfeng , Hui Fei , Iglesias Vanessa , Porti Marc , Nafria Montserrat , Miranda Enrique , Bersuker Gennadi , Lanza Mario
Published: September 2014

A new generation of non-volatile memories that store information in a metal/insulator/metal cell with switchable electrical resistance is gaining attention due to its simple structure and high yield. Despite extensive device level measurements have been performed, the origin of the resistive switching remains unclear. In this work, we use a disruptive approach to characterize cyclic resistivity changes at the nanoscale, combining a standard conductive atomic force microscope and a semiconductor parameter analyzer. Using this setup, we are able to assess the origin of resistive switching in Hafnium-based oxides, which takes place at the grain boundaries of polycrystalline stacks, and further calculations corroborate the local nature of this phenomenon.
Anisotropic Magnetoresistance of Ferromagnetic Conductive Filament in Resistive Switching Memory
Authors: Otsuka Shintaro , Hamada Yoshifumi , Shimizu Tomohiro , Shingubara Shoso
Published: September 2014

We report on an origin of the conductive filament (CF) for a Ni/HfO2/Pt resistive switching memory. The device shows SET process (from high to low resistance), when positive bias is applied to the Ni electrode. RESET process (from low to high resistance) occurs during both positive and negative biases. We investigated the temperature dependence of resistance and magnetoresistance for the low resistance states (LRS) of the device, which were formed with different amount of a current compliance. LRS formed with the high current compliance has a linear temperature dependence of resistance compared with that formed with the low current compliance. Moreover, anisotropic magnetoresistance was observed for the LRS, which was formed with the high current compliance. This suggests that CF is made of the ferromagnetic Ni atoms when a high current compliance was used to form LRS.
Progresses in Modeling HfOx RRAM Operations and Variability
Authors: Larcher Luca , Pirrotta Onofrio , Puglisi Francesco Maria , Padovani Andrea , Pavan Paolo , Vandelli Luca
Published: September 2014

This paper reports on recent progresses in modeling bi-polar RRAM devices based on hafnium oxide. The unique modeling environment adopted for the simulation of device operations accounts self-consistently for the charge and ion transport, and the structural device modification occurring during forming and set/reset operations. Reliability mechanisms as well as the major sources of devices variability are included thanks to a multi-scale approach that connects the electrical device performance to the atomic-level material properties. The modeling methodology can be successfully applied to both improve device performances and fabrication process of state-of-the-art RRAM devices, and devise device solutions for future 3D RRAM architectures.
(Invited) Multilevel Cell Nonvolatile Memory with Field-effect Transistor Using Crystalline Oxide Semiconductor
Authors: Matsuzaki Takanori , Onuki Tatsuya , Nagatsuka Shuhei , Inoue Hiroki , Ishizu Takahiko , Miyairi Hidekazu , Sakakura Masayuki , Atsumi Tomoaki , Shionoiri Yutaka , Kato Kiyoshi , Okuda Takashi , Yamamoto Yoshitaka , Koyama Jun , Yamazaki Shunpei
Published: September 2014

Multilevel cell nonvolatile memory has been developed with a field-effect transistor (FET) containing a crystalline oxide semiconductor (OS), specifically c-axis aligned crystalline In-Ga-Zn-oxide (CAAC-IGZO). The memory is called nonvolatile oxide semiconductor random access memory (NOSRAM). A NOSRAM cell consists of a CAAC-IGZO FET, a p-channel MOS (PMOS) transistor, and a cell capacitor. We have demonstrated that a single 3-bit NOSRAM cell has an endurance of 1012 cycles and a write time of 5 ns. The 6σ tolerance for cell V
th distribution of a test chip including an 18-kbit NOSRAM cell array is 109 mV. The test chip achieves a 3-bit/cell NOSRAM.
(Invited) Materials and Physics Challenges for Spin Transfer Torque Magnetic Random Access Memories
Authors: Heinonen Olle
Published: September 2014

Magnetic random access memories utilizing the spin transfer torque effect for writing information are a strong contender for non-volatile memories scalable to the 20 nm node, and perhaps beyond. I will here examine how these devices behave as the device size is scaled down from 70 nm size to 20 nm. As device sizes go below ~50 nm, the size becomes comparable to intrinsic magnetic length scales and the device behavior does not simply scale with size. This has implications for the device design and puts additional constraints on the materials in the device.
Microstructure Control of Absorber Sb2S3 and p-Type Semiconductor CuSCN for Semiconductor-Sensitized Solar Cells (TiO2/Sb2S3/CuSCN)
Authors: Zhang Xi , Yoshioka Shohei , Loew Noya , Ihara Manabu
Published: September 2014

Semiconductor-sensitized solar cells (SSSCs) were fabricated with a planar n-type TiO2 film, an antimony sulfide (Sb2S3) thin film as the absorber, and a transparent p-type CuSCN film. The deposition amount of Sb2S3 and the pn junction interface condition significantly affected the generation and recombination of photo carriers. Analysis of the microstructure and chemical state of the Sb2S3, and the microstructure of CuSCN films showed that the homogeneity of the Sb2S3 and CuSCN films, the oxidation of Sb2S3 and the CUSCN thickness determined the optimal amount of Sb2S3 and the highest photoelectric conversion efficiency. For the ETA solar cell with the highest photoelectric conversion efficiency (1.67%), Sb2S3 was deposited by sputtering (SP) and CuSCN by wiping (WI).
Spray Pyrloysed TiO2 Dye Sensitized Solar Cells
Authors: Murali Kollegal Ramakrishna
Published: September 2014

Titanium di oxide films were deposited by spray pyrolysis technique on ITO coated glass substrates at different substrate temperatures in the range of 375οC - 450 οC. The films were post heat treated in air for 1 hour. Resistivity of the films was in the range of meghohms. Annealing in vacuum decreased the resistivity by three orders. Band gap of the films decreased from 3.45 eV to 3.20 eV with increase of substrate temperarture. Dye sensitized solar cells were fabricated with hibiscus,strawberry and chlorophyll dyes and combination of the three dyes. The photooutput was highest for the combination of dyes and lowest for the hibiscus dyes
(Invited) Finite Element Model Simulations to Assist the Design of Microdevices Dedicated to the Localized Electroporation of Mouse Embryos
Authors: Zhao Xuan , Mazari Elsa , Suárez-Boomgaard Diana , Migeotte Isabelle , Perea-Gomez Aitana , Gosse Charlie
Published: September 2014

We have recently developed a microsystem to electroporate a few cells at the surface of early post-implantation mouse embryos. We could achieve the efficient, reproducible, and safe transfection of various genetic markers, which allowed single cell fate studies during morphogenesis. However, our single-use polymeric device necessitated to be fabricated in a clean room the day before each experiment. Thus, we here introduce an all-glass chip that any biologist can easily recycle in its laboratory. Most importantly, during the technological evolution process we could validate a comprehensive design strategy based on finite element model simulations. Indeed, both the embryo and the microsystem were represented as very simple electric objects and stationary computations enabled to properly predict the voltage pulse amplitude that would yield optimal device performances.
(Invited) Metal-Semiconductor-Metal Photocurrent Chip for Hydrogen Peroxide and Biomolecular Sensing with Chemiluminescence
Authors: Ko Fu-Hsiang , Lin Ching-Chang , Sun Da-Shiuan , Pan Tung-Ming
Published: September 2014

Photodetectors are generally the most promising, representative and widely-used type of detectors, and the applications of photodetectors are quite extensively. Photodetectors are made of photosensitive elements which are able to turn the light signal into electrical signal. Owing to the nature of fast responding speed and capability of large volume manufacturing, it provides photodetectors an advantageous future in biomedical sensing territory. This study focuses on fabrication method of the flexible photodetectors and application to biomolecule sensing through luminescence. The photosensitive element is based on silicon wafer which is treated with chemical etching process to achieve pliable characteristic. Then, the metal-semiconductor-metal structural flexible photodetectors are achieved after integrated with simple fabricating processes. The accomplished devices are handled with immobilization steps to fix the target enzyme which is able to catalyze the luminescent reaction. We provide a portable biomolecule sensor with outstanding flexible characteristic and high sensitivity and it exhibits illustrious stable consequence in various situations.
A Novel Ultra-Low Detection Limit Hydrogen Peroxide Sensor Based on Horseradish Peroxidase Immobilized Polyaniline Film
Authors: Fang Kuan Chung , Chu Chia Ho , Hsu Chen-Pin , Kang Yen-Wen , Fang Jung-Ying , Hsu Chia-Hsien , Huang Yu-Fen , Chen Chih-Chen , Li Sheng-Shian , Yeh J. Andrew , Yao Da-Jeng , Wang Yu-Lin
Published: September 2014

In this study, an ultra-sensitive hydrogen peroxide sensor was fabricated by using horseradish peroxidase (HRP)-immobilized conducting polymer, polyaniline (PANI). With the proposed detection mechanism, hydrogen peroxide first oxidizes HRP, which then oxidizes polyaniline, thus resulting in decreased conductivity of the polyaniline thin film. The reduced HRP can be further oxidized by hydrogen peroxide and the cycle of the oxidation/reduction interaction would proceed until all hydrogen peroxide are reacted. It leads to the high sensitivity of the sensor due to the signal contributed from all reacted hydrogen peroxide. The detection limit of the hydrogen peroxide sensor is 0.7 nM. The detecting range of concentration of H2O2 is from 0.7 nM to 1 μM. The simple fabrication for the sensor allows the sensor to be cost-effective and disposable. This ultra-sensitive hydrogen peroxide sensor is promising in applications for low concentration hydrogen peroxide detections, such as the reactive oxygen species (ROS) in oxidative stress studies.
Measurement and Modeling of the M13 Bacteriophages Transport in the Conical-Shaped Nanopore
Authors: Lee Che-Yen , Hsiao Yi-Hsin , Yu Ji-Cheng , Hsu Chih-Wei , Hsu Chia-Hsien , Chen Chihchen
Published: September 2014

Multiple parameters affecting the transmembrane current in resistive pulse sensing were investigated, including the size, shape, tilt angle, path and relative position of the translocating sample, as well as the diameter of the conical-shaped nanopore and the voltage applied. M13 bacteriophages and monodisperse carboxylated polystyrene beads of 212 nm in diameter were used in this study. The finite-element simulation and experimental results showed the tilt angle, path and shape of the sample indeed affect the magnitude of the blockade current. Interestingly, current peaks of the opposite polarity to the blockade current were observed under certain conditions.
Capacitive Current Induced by dsDNA for Biosensor Applications
Authors: Hsu Chen-Pin , Huang Yu-Fen , Wang Yu-Lin
Published: September 2014

The capacitive current brings important information of electrical components. It may be affected by surface modification or ion motion in a aqueous phase measured with electrodes. In this study, duplex DNA (dsDNA) was immobilized on gold electrodes and the capacitive current was measured in buffer solution with high salt concentration in a pulse stimulus. The capacitive current relaxed, which may be involved with ions and the DNA. DNA may stretch, extend, or swing under electric filed in solution. The capacitive current was recorded by difference pulse width before the DNA fully relaxed. Doxorubicin can insert to G-C base pairs in dsDNA and change the elasticity. The capacitive current was decreased with higher concentration of doxorubicin. In this study, we can detect low concentration of doxorubicin (1nM) binding with dsDNA, showing that this technique is promising for biosensor applications.
Novel Cholesterol Sensor Based on Ultra-Low Detection Limit Hydrogen Peroxide Sensor
Authors: Chu Chia Ho , Fang Kuan Chung , Hsu Chen-Pin , Kang Yen-Wen , Fang Jung-Ying , Hsu Chia-Hsien , Huang Yu-Fen , Chen Chih-Chen , Li Sheng-Shian , Yeh J. Andrew , Yao Da-Jeng , Wang Yu-Lin
Published: September 2014

In this work, we report a novel method to fabricate the low cost cholesterol sensor based on ultra-sensitive hydrogen peroxide sensor. The sensor can directly detect different concentrations of cholesterol in a phosphate buffer (pH=7.0) through enzymatically generated hydrogen peroxide and only need very small amount of sample. The sensor provides a real-time response towards a wide linear range up to 400 mg/dl cholesterol concentration. Because of the simple structural design and fabrication, the sensor can be used for a cheap, efficient, and portable sensor system.
Recent Advances in Semiconductor Nanowire Heterostructures
Authors: Jackson Howard E , Smith Leigh M. , Jagadish Chennupati
Published: September 2014

We review a selection of recent optical experiments which provide unique characterizations of the energy landscape in semiconductor nanowires, both simple nanowires and more complex semiconductor heterostructures. The optical experiments include the techniques of photoluminescence, time-resolved photoluminescence, photoluminescence excitation spectroscopy, photocurrent spectroscopy, and Raman scattering brought to bear on structures from simple core-shell structures, to axial heterostructures, to core-multiple-shell heterostructures. The physics that is illuminated ranges from localization of excitons in GaAs quantum well tubes, to strain in GaAs/GaP axial heterostructures, to carrier relaxation dynamics in GaAs/AlGaAs core-shell NWs probed by the new technique of transient Rayleigh scattering.
Integration of Photodefinable Polybenzoxazole as Intermetal Dielectric for GaAs HBT Technology
Authors: Yota Jiro , Do Benny
Published: September 2014

Photodefinable polybenzoxazole (PBO) has been integrated as intermetal dielectric in GaAs hetero-junction bipolar transistor (HBT) technology. Process module optimization and integration studies were performed and the results and process flow were compared to those of dry-etch polyimide. The photodefinable PBO is shown to allow the intermetal dielectric process flow to be simplified and the number of processes and equipment to be reduced. Results show that PBO has more planarity than polyimide, when coated on GaAs HBT wafers, which typically have significant topography. The photolithography coat, expose, and develop processes were optimized to obtain the desired dielectric thickness and the required via dimension and sidewall profile, in addition the removal of the PBO from the die street. The PBO thermal curing process was performed at 300oC, while plasma ashing was performed to remove any PBO residue from the bottom of the vias. These results show that the photodefinable PBO film is compatible with, is suitable for, and can be integrated as intermetal dielectric in GaAs HBT technology.
Behaviors of Carbon Atoms during Plasma Oxidation of 4H-SiC(0001) Surfaces near Room Temperature
Authors: Saito Naoki , Mori Daichi , Imafuku Akito , Kawai Kentaro , Sano Yasuhisa , Morita Mizuho , Arima Kenta
Published: September 2014

The behavior of C atoms during the thermal oxidation of a SiC surface has been a subject of controversy. In this study, we oxidize a SiC surface by atmospheric-pressure plasma treatment near room temperature. We find that more C atoms are included in the SiO2 film after plasma oxidation than after conventional thermal oxidation in O2 ambient at 1000°C, which is probably caused by the difference in oxidation temperature. We demonstrate that plasma oxidation followed by HF etching results in clusters of C atoms remaining at the SiO2/SiC interface. We speculate from X-ray photoelectron spectroscopy results that the C clusters are mixtures of C-C, CH2 and C-O. These C clusters allow us to obtain graphene with few pits because they are an additional C source for forming a homogeneous buffer layer over a SiC surface at elevated temperatures in ultrahigh vacuum.
New Approaches to Realizing High Power Nitride Based Field Effect Transistors
Authors: Shur Michael , Simin Grigory , Gaska Remis
Published: September 2014

We report on several key innovations to enable high performance/high reliability of nitride based FETs that include (1) the use of Perforated Channel (PC) design; (2) surface application of Low Conducting Layers (LCLs); (3) the combination of these two approaches (for achieving the ultimate power performance at the highest switching frequencies with minimum losses); (4) novel device geometries (combining the best features of lateral and vertical devices for normally-off transistors); (5) improved control of self-heating and better heat dissipation. We also review our recent results exploring the PC channel and LCL designs . Our experimental and simulation results demonstrated a sharp increase in the breakdown voltage, a large enhancement of the cutoff frequency, a better device stability and smaller spreading of the device parameters for higher yield, improved manufacturability, and smaller self-heating due to a lower thermal impedance.
Simulation of Radiation Damage in GaN HEMT Structures
Authors: Patrick Erin , Choudhury Mo , Law Mark E
Published: September 2014

For decades TCAD has been a useful tool for device design. By varying structure and composition, device designers have been able to explore alternative designs and optimize device performance. Conversely, changes to device structure and properties due to environmental changes (i.e., radiation) can be modeled using TCAD. This paper explores how trap generation from radiation can alter transport and field strength in AlGaN/GaN HEMTs.
Low Power Zinc-Oxide Based Charge Trapping Memory with Embedded Silicon Nanoparticles
Authors: Nayfeh Ammar , Okyay Ali , El-Atab Nazek , Ozcan Ayse , Alkis Sabri
Published: September 2014

In this work, a bottom-gate charge trapping memory device with Zinc-Oxide (ZnO) channel and 2-nm Si nanoparticles (Si-NPs) embedded in ZnO charge trapping layer is demonstrated. The active layers of the memory device are deposited by atomic layer deposition (ALD) and the Si-NPs are deposited by spin coating. The Si-NPs memory exhibits a threshold voltage (Vt) shift of 6.3 V at an operating voltage of -10/10 V while 2.6 V Vt shift is obtained without nanoparticles confirming that the Si-NPs act as energy states within the bandgap of the ZnO layer. In addition, a 3.4 V Vt is achieved at a very low operating voltage of -1 V/1 V due to the charging of the Si-NPs through Poole-Frenkel emission mechanism at an electric field across the tunnel oxide E > 0.36 MV/cm. The results highlight a promising technology for future ultra-low power memory devices.
A Weighted Two-Level Bregman Method with Dictionary Updating for Nonconvex MR Image Reconstruction
Authors: Liu Qiegen , Peng Xi , Liu Jianbo , Yang Dingcheng , Liang Dong
Published: September 2014

Nonconvex optimization has shown that it needs substantially fewer measurements thanl1minimization for exact recovery under fixed transform/overcomplete dictionary. In this work, two efficient numerical algorithms which are unified by the method named weighted two-level Bregman method with dictionary updating (WTBMDU) are proposed for solvinglpoptimization under the dictionary learning model and subjecting the fidelity to the partial measurements. By incorporating the iteratively reweighted norm into the two-level Bregman iteration method with dictionary updating scheme (TBMDU), the modified alternating direction method (ADM) solves the model of pursuing the approximatedlp-norm penalty efficiently. Specifically, the algorithms converge after a relatively small number of iterations, under the formulation of iteratively reweightedl1andl2minimization. Experimental results on MR image simulations and real MR data, under a variety of sampling trajectories and acceleration factors, consistently demonstrate that the proposed method can efficiently reconstruct MR images from highly undersampledk-space data and presents advantages over the current state-of-the-art reconstruction approaches, in terms of higher PSNR and lower HFEN values.
Synchronization and Lag Synchronization of Hyperchaotic Memristor‐Based Chua’s Circuits
Authors: Huang Junjian , Li Chuandong , Huang Tingwen , Wang Hui , Wang Xin
Published: September 2014

A memristor‐based five‐dimensional (5D) hyperchaotic Chua’s circuit is proposed. Based on the Lyapunov stability theorem, the controllers are designed to realize the synchronization and lag synchronization between the hyperchaotic memristor‐based Chua’s circuits under different initial values, respectively. Numerical simulations are also presented to show the effectiveness and feasibility of the theoretical results.
Silver(I) Catalyzed Photochemical Oxidation of Methylene Blue and Safranine-O by Peroxydisulphate: A Green Chemical Approach
Authors: Chhajed Ravisha , Sharma Sanyogita , Ameta Rakshit , Punjabi Pinki B.
Published: September 2014

In the present investigation, a comparative study of silver(I) catalysed photochemical oxidation of methylene blue (MB) and safranine-O (SO) by peroxydisulphate has been reported. The effect of different parameters, such as pH, concentration of peroxydisulphate, silver nitrate, and light intensity, on the reaction rate has been observed. The progress of the photochemical oxidation was monitored spectrophotometrically. The optimum conditions for photochemical oxidation were achieved. The dyes were completely oxidized and degraded into CO2 and H2O. A tentative mechanism for silver(I) catalyzed photochemical oxidation of these dyes by peroxydisulphate has also been proposed.
Group Measures and Modeling for Social Networks
Authors: Levorato Vincent
Published: September 2014

Social network modeling is generally based on graph theory, which allows for study of dynamics and emerging phenomena. However, in terms of neighborhood, the graphs are not necessarily adapted to represent complex interactions, and the neighborhood of a group of vertices can be inferred from the neighborhoods of each vertex composing that group. In our study, we consider that a group has to be considered as a complex system where emerging phenomena can appear. In this paper, a formalism is proposed to resolve this problematic by modeling groups in social networks using pretopology as a generalization of the graph theory. After giving some definitions and examples of modeling, we show how some measures used in social network analysis (degree, betweenness, and closeness) can be also generalized to consider a group as a whole entity.
Positive Solutions of a Third‐Order Three‐Point BVP with Sign‐Changing Green’s Function
Authors: Gao Li-Juan , Sun Jian-Ping
Published: September 2014

We are concerned with the following third‐order three‐point boundary value problem: u′′′(t) = f(t,  u(t)),  t ∈ [0,  1],  u′(0) = u(1) = 0 and  u′′(η) − αu′(1) = 0, where α ∈ [0,  1 and η ∈ [(14 + α)/(24 − 3α), 1. Although the corresponding Green’s function is sign‐changing, we still obtain the existence of at least two positive and decreasing solutions under some suitable conditions on f by using the two‐fixed‐point theorem due to Avery and Henderson.
Stability and Bifurcation of a Computer Virus Propagation Model with Delay and Incomplete Antivirus Ability
Authors: Ren Jianguo , Xu Yonghong
Published: September 2014

A new computer virus propagation model with delay and incomplete antivirus ability is formulated and its global dynamics is analyzed. The existence and stability of the equilibria are investigated by resorting to the threshold value R0. By analysis, it is found that the model may undergo a Hopf bifurcation induced by the delay. Correspondingly, the critical value of the Hopf bifurcation is obtained. Using Lyapunov functional approach, it is proved that, under suitable conditions, the unique virus‐free equilibrium is globally asymptotically stable if R0 < 1, whereas the virus equilibrium is globally asymptotically stable if R0 > 1. Numerical examples are presented to illustrate possible behavioral scenarios of the mode.
Heat and Mass Transfer on MHD Flow of a Viscoelastic Fluid through Porous Media over a Shrinking Sheet
Authors: Bhukta D. , Dash G. C. , Mishra S. R.
Published: September 2014

An attempt has been made to study the heat and mass transfer effect in a boundary layer flow through porous medium of an electrically conducting viscoelastic fluid over a shrinking sheet subject to transverse magnetic field in the presence of heat source. Effects of radiation, viscous dissipation, and uniform heat sink on the heat transfer have been considered. The method of solution involves similarity transformation. The coupled nonlinear partial differential equations representing momentum, concentration, and nonhomogenous heat equation are reduced into a set of nonlinear ordinary differential equations. The transformed equations are solved by applying Kummer’s function. The exact solution of temperature field is obtained for power-law surface temperature (PST) as well as power-law heat flux (PHF) boundary condition. The interaction of magnetic field is proved to be counterproductive in enhancing velocity and concentration distribution, whereas presence of porous matrix reduces the temperature field at all points.
Preparation and Optical Investigations of [(Sr1-xBix)TiO3]-[2SiO2B2O3]-[CeO2] Glasses
Authors: Gautam Chandkiram , Singh Anod Kumar , Madheshiya Abhishek
Published: September 2014

We are reporting synthesis and structural and optical investigation of strontium bismuth titanate borosilicate glasses with addition of one mole percent cerium oxide (CeO2). Glasses were synthesized by conventional rapid melt quench method. XRD studies of the glass samples confirm the amorphous nature. Infrared absorption spectra various strontium bismuth titanate borosilicate glass samples having glass system 60[(Sr1-xBix)TiO3]-39[2SiO2B2O3]-1[CeO2] (x=0.0,0.1,0.2,0.4) were recorded over a continuous spectral range from 400 to 4000 cm−1. IR spectra were analyzed to determine and differentiate of various vibrational modes in the structural change. Raman spectroscopy of all glass samples was also carried out in the wave number range from 200 to 2000 cm−1.
Short and Long Term Outcomes Associated with Fetal Cholelithiasis: A Report of Two Cases with Antenatal Diagnosis and Postnatal Follow-Up
Authors: Troyano-Luque Juan , Padilla-Pérez Ana , Martínez-Wallin Ingrid , Álvarez de la Rosa Margarita , Mastrolia Salvatore Andrea , Trujillo José Luis , Pérez-Medina Tirso
Published: September 2014

The aims of this study were to present and discuss ultrasound findings of prenatal fetal cholelithiasis in two cases with different etiology and evolution. Case 1: a pregnant woman from sub-Saharan Africa, suffering from Lyme disease, was treated with ceftriaxone sodium. Six weeks later, biliary sludge associated with polyhydramnios was detected in the fetus and the fetal growth percentile was 14. Emergency caesarean was performed at 36 weeks of gestation due to fetal distress. Biliary sludge persists in the two-and-a-half-year-old child. Case 2: the fetus of a Caucasian woman with normal pregnancy showed multiple cholelithiasis associated with polyhydramnios at 31 weeks of gestation. At 39 weeks and 4 days, cesarean section was performed due to lack of dilation. The biliary disease resolved spontaneously at seven months of age, with no associated abnormalities. In conclusion, prenatal diagnosis of cholelithiasis is straightforward, but prognosis cannot be defined yet. Serious complications do not arise in 70% of cases, but severe diseases may ensue in 20%. Persistence of cholelithiasis after one year of age results in cholelithiasis in childhood and beyond. Biliary sludge is associated with worse prognosis than cholelithiasis when it appears before 28 weeks of gestation.
The Value of Intraoperative Frozen Section Analysis for Margin Status in Breast Conservation Surgery in a Nontertiary Institution
Authors: Tan Mona P. , Sitoh Nadya Y. , Sim Amanda S.
Published: September 2014

Introduction. Breast conservation treatment (BCT) for early-stage breast malignancies requires negative margins and good cosmesis. Reoperations may be needed to achieve negative margins, which can have an adverse impact on outcomes. This study was performed to evaluate the efficacy of intraoperative frozen section analysis (IFSA) for margin assessment to reduce excision rates.Methods. All patients treated at the authors’ private healthcare facility between 2009 and 2011 for breast cancer were included in the study. Those for whom BCT was intended underwent wide excision with IFSA. Six margins of the excised tissue, and the sentinel lymph node (SLN), where appropriate, were submitted for IFSA. Patient demographics, tumour characteristics, number of operations performed, and outcomes were analysed.Results. Of the 161 patients analysed, 138 (85.7%) had successful breast conservation. Four patients required a reoperation for incomplete surgical extirpation. One had a false negative SLN assessment on IFSA, and was returned to the operating room for an axillary dissection. Three patients required reoperations for inadvertently missed multicentric disease. None had false negative margin evaluation with IFSA necessitating reexcision.Conclusion. The use of IFSA allows low rates of reoperation with BCT. Further research is needed to establish consistency in low reexcision rates for cost-effectiveness and optimum resource allocation.
Delayed Cerebral Radiation Necrosis after Neutron Beam Radiation of a Parotid Adenocarcinoma: A Case Report and Review of the Literature
Authors: Hong Christopher S. , Gokozan Hamza N. , Otero José J. , Guiou Michael , Elder J. Bradley
Published: September 2014

Cerebral radiation necrosis (CRN) is a well described possible complication of radiation for treatment of intracranial pathology. However, CRN as sequelae of radiation to extracranial sites is rare. Neutron beam radiation is a highly potent form of radiotherapy that may be used to treat malignant tumors of the salivary glands. This report describes a patient who underwent neutron beam radiation for a parotid adenocarcinoma and who developed biopsy-confirmed temporal lobe radiation necrosis thirty months later. This represents the longest time interval described to date, from initial neutron radiation for extracranial pathology to development of CRN. Two other detailed case studies exist in the literature and are described in this report. These reports as well as our patient’s case are reviewed, and additional recommendations are made to minimize the development of CRN after extracranial neutron beam radiation. Physicians should include the possible diagnosis of CRN in any patient with new neurologic signs or symptoms and a history of head and neck radiation that included planned fields extending to the base of the skull. Counseling of patients prior to neutron beam radiation should include potential neurologic complications associated with CRN and risks of treatment for CRN including neurosurgical intervention.
Kinetic Treatment of the Reaction of Fructose and N-Bromosuccinimide in Cationic/Anionic/Nonionic Micelles
Authors: Singh Minu
Published: September 2014

The kinetics of oxidation of fructose by N-bromosuccinimide in acidic medium in the absence and presence of cationic, anionic, and nonionic surfactants has been measured iodometrically under pseudo-first-order condition. The oxidation kinetics of fructose by N-bromosuccinimide shows a first-order dependence on N-bromosuccinimide, fractional order dependence on fructose, and negative fractional order dependence on sulfuric acid. The kinetics is treated using Berezin’s micellar model that was previously used for the catalysis and inhibition of the reaction. The determined stoichiometric ratio was 1 : 1 (fructose : N-bromosuccinimide). The variation of Hg(OAC)2and succinimide (reaction product) has insignificant effect on reaction rate. Effects of surfactants, added acrylonitrile, added salts, and solvent composition variation have been studied. Activation parameters for the reaction have been evaluated from Arrhenius plot by studying the reaction at different temperatures. The rate law has been derived on the basis of obtained data. A plausible mechanism has been proposed from the results of kinetic studies, reaction stoichiometry, and product analysis.
Impact of Age and Duration of Symptoms on Surgical Outcome of Single-Level Microscopic Anterior Cervical Discectomy and Fusion in the Patients with Cervical Spondylotic Radiculopathy
Authors: Omidi-Kashani Farzad , Ghayem Hasankhani Ebrahim , Ghandehari Reza
Published: September 2014

We aim to evaluate the impact of age and duration of symptoms on surgical outcome of the patients with cervical spondylotic radiculopathy (CSR) who had been treated by single-level microscopic anterior cervical discectomy and fusion (ACDF). We retrospectively evaluated 68 patients (48 female and 20 male) with a mean age of 41.2±4.3 (ranged from 24 to 72 years old) in our Orthopedic Department, Imam Reza Hospital. They were followed up for 31.25±4.1 months (ranged from 25 to 65 months). Pain and disability were assessed by Visual Analogue Scale (VAS) and Neck Disability Index (NDI) questionnaires in preoperative and last follow-up visits. Functional outcome was eventually evaluated by Odom’s criteria. Surgery could significantly improve pain and disability from preoperative 6.2±1.4 and 22.2±6.2 to 3.5±2.0 and 8.7±5.2 (1–21) at the last follow-up visit, respectively. Satisfactory outcomes were observed in 89.7%. Symptom duration of more and less than six months had no effect on surgical outcome, but the results showed a statistically significant difference in NDI improvement in favor of the patients aged more than 45 years (P=0.032), although pain improvement was similar in the two groups.
The Impact of the PSP on Software Quality: Eliminating the Learning Effect Threat through a Controlled Experiment
Authors: Grazioli Fernanda , Vallespir Diego , Pérez Leticia , Moreno Silvana
Published: September 2014

Data from the Personal Software Process (PSP) courses indicate that the PSP improves the quality of the developed programs. However, since the programs (exercises of the course) are in the same application domain, the improvement could be due to programming repetition. In this research we try to eliminate this threat to validity in order to confirm that the quality improvement is due to the PSP. In a previous study we designed and performed a controlled experiment with software engineering undergraduate students at the Universidad de la República. The students performed the same exercises of the PSP course but without applying the PSP techniques. Here we present a replication of this experiment. The results indicate that the PSP and not programming repetition is the most plausible cause of the important software quality improvements.
Attitude Estimation Based on the Spherical Simplex Transformation Modified Unscented Kalman Filter
Authors: Zhao Jianwei , Jia Weimin , Wang Rong , Yan Zhixiang
Published: September 2014

An antenna attitude estimation algorithm is proposed to improve the antenna pointing accuracy for the satellite communication on‐the‐move. The extrapolated angular acceleration is adopted to improve the performance of the time response. The states of the system are modified according to the modification rules. The spherical simplex transformation unscented Kalman filter is used to improve the precision of the estimated attitude and decrease the calculation of the unscented Kalman filter. The experiment results show that the proposed algorithm can improve the instantaneity of the estimated attitude and the precision of the antenna pointing, which meets the requirement of the antenna pointing.
Fabrication of Compact Microstrip Line‐Based Balun‐Bandpass Filter with High Common‐Mode Suppression
Authors: Chen Chia-Mao , Chang Shoou-Jinn , Pan Yen-Liang , Chen Cheng-Yi , Yang Cheng-Fu
Published: September 2014

A new type of balun‐bandpass filter was proposed based on the traditional coupled‐line theory and folded open‐loop ring resonators (OLRRs) configuration. For that, a new device with both filter‐type and balun‐type characteristics was investigated and fabricated. Both magnetic and electric coupling structures were implemented to provide high performance balun‐bandpass responses. The fabricated balun‐bandpass filters had a wide bandwidth more than 200 MHz and a low insertion loss less than 2.51 dB at a center frequency of 2.6 GHz. The differences between the two outputs were below 0.4 dB in magnitude and within 180 ± 7° in phase. Also, the balun‐bandpass filter presented an excellent common‐mode rejection ratio over 25 dB in the passband. An advanced design methodology had been adopted based on EM simulation for making these designed parameters of OLRRs, microstrip lines, and open stubs. The measured frequency responses agreed well with simulated ones.
CD98hc (SLC3A2) Loss Protects Against Ras-Driven Tumorigenesis by Modulating Integrin-Mediated Mechanotransduction
Authors: Estrach Soline , Lee Sin-Ae , Boulter Etienne , Pisano Sabrina , Errante Aurélia , Tissot Floriane S. , Cailleteau Laurence , Pons Catherine , Ginsberg Mark H. , Féral Chloé C.
Published: September 2014

CD98hc (SLC3A2) is the heavy chain component of the dimeric transmembrane glycoprotein CD98, which comprises the large neutral amino acid transporter LAT1 (SLC7A5) in cells. Overexpression of CD98hc occurs widely in cancer cells and is associated with poor prognosis clinically, but its exact contributions to tumorigenesis are uncertain. In this study, we showed that genetic deficiency of CD98hc protects against Ras-driven skin carcinogenesis. Deleting CD98hc after tumor induction was also sufficient to cause regression of existing tumors. Investigations into the basis for these effects defined two new functions of CD98hc that contribute to epithelial cancer beyond an intrinsic effect of CD98hc on tumor cell proliferation. First, CD98hc increased the stiffness of the tumor microenvironment. Second, CD98hc amplified the capacity of cells to respond to matrix rigidity, an essential factor in tumor development. Mechanistically, CD98hc mediated this stiffness sensing by increasing Rho kinase (ROCK) activity, resulting in increased transcription mediated by YAP/TAZ, a nuclear relay for mechanical signals. Our results suggest that CD98hc contributes to carcinogenesis by amplifying a positive feedback loop, which increases both extracellular matrix stiffness and resulting cellular responses. This work supports a rationale to explore the use of CD98hc inhibitors as cancer therapeutics. Cancer Res; 74(23); 6878–89. ©2014 AACR.