bluuebunny/crossref_metadata_2025 huggingface dataset:
Deposition of TiO2 Passivation Layer by Plasma Enhanced Chemical Vapor Deposition between the Transparent Conducting Oxide and Mesoporous TiO2 Electrode in Dye Sensitized Solar Cells
Authors: Lee Su Young , Kim Sang Ho
Published: October 2012

The characteristic of TiO2 passivation layers grown by plasma enhanced chemical vapor deposition as a function of its thickness on F-doped SnO2 (FTO) electrode was investigated. The thickness of TiO2 passivation layer was varied from 30 to 200 nm by controlling the deposition time. The electric resistance of the TiO2 layers was depended on the thickness, so the optimized thickness in enhancing the connection and reducing the recombination of electrons on the surface of FTO electrode was determined. The dye sensitized solar cells fabricated with 40 nm thick TiO2 passivation layer showed the maximum power conversion efficiency of 6.93%. It was due to the effective connection of mesoporous TiO2 and FTO and the prevention of electron recombination from the FTO to electrolyte. The reduced resistance, enlarged electron diffusion length measured by the electrochemical impedance spectroscopy, intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy identified the connection and anti-recombination effect.
Crystalline Silicon/Graphene Oxide Hybrid Junction Solar Cells
Authors: Liu Qiming , Wanatabe Fumiya , Hoshino Aya , Ishikawa Ryo , Gotou Takuya , Ueno Keiji , Shirai Hajime
Published: October 2012

Soluble graphene oxide (GO) and plasma-reduced (pr-) GO were investigated using crystalline silicon (c-Si) (100)/GO/pr-GO hybrid junction solar cells. Their photovoltaic performances were compared with those of c-Si/GO/pristine conductive poly(ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) heterojunction and c-Si/PEDOT:PSS:GO composite devices. The c-Si/GO/pr-GO and conductive PEDOT:PSS/Al heterojunction solar cells showed power conversion efficiencies of 6.5 and 8.2%, respectively, under illumination with AM 1.5 G 100 mW/cm2 simulated solar light. A higher performance of 10.7% was achieved using the PEDOT:PSS:GO (12.5 wt %) composite device. These findings imply that soluble GO, pr-GO, and the PEDOT:PSS:GO composite are promising materials as hole transport and transparent conductive layers for c-Si/organic hybrid junction solar cells.
Fabrication of Graded Band Gap Amorphous Carbon Nitride Thin Films for New Generation Photovoltaic Applications
Authors: Iwasaki Chihiro , Aono Masami , Tamura Naoyuki , Kitazawa Nobuaki , Watanabe Yoshihisa
Published: October 2012

We have reported the fabrication of amorphous carbon nitride, a-CN
x
, films with a graded band gap structure to improve their photoconductivity and their structural, optical, and electrical properties are studied. In this study, two different structured a-CN
x
films with graded band gap structures were compared with single-layered a-CN
x
films. One of the graded band gap structure films consists of four stacked layers with different band gaps (multilayered film), and the other film consists of one layer with a gradually changed band gap (graded-layered film). All of the a-CN
x
films are prepared by the reactive radio frequency magnetron sputtering method using a graphite target in pure nitrogen gas. The ratio of photo- and dark-conductivity, σp/σd, of the multilayered film is quite low. In contrast, the σp/σd value of the graded-layered a-CN
x
film is about 11 times larger than that of the single-layered film and 80 times larger than that of the multilayered film.
Analysis of Chlorine Ions in Antimony-Doped Tin Oxide Thin Film Using Synchrotron Grazing Incidence X-ray Diffraction
Authors: Lin Yang-Yi , Wu Albert T. , Ku Ching-Shun , Lee Hsin-Yi
Published: October 2012

Antimony-doped tin oxide (SnO2:Sb, ATO) films have been deposited on glass substrates using atmospheric pressure chemical vapor deposition (APCVD) method. The precursors are mixed with SnCl4, SbCl5, and O2 to prepare the films. This study used synchrotron grazing incidence X-ray diffraction (GIXRD) to investigate the film microstructure. Our results show that the precursors of chlorine ions were involved in the doping mechanism, causing the microstructure of films to change slightly. The film has an average transmittance between 85.8 and 82.1% within a visible spectral range from 400 to 800 nm. The minimal resistivity was 6.1×10-4 Ω cm after doping. The synchrotron GIXRD data show that the chlorine ions caused the lattice constant change. A possible mechanism was proposed to explain the enhancement in electrical property due to chlorine dopants.
Effect of Sol–Gel-Derived ZnO Interfacial Layer on the Photovoltaic Properties of Polymer Solar Cells
Authors: Kim Jun Young , Lee Hyunkoo , Park Jungho , Lee Donggu , Song Hyung-Jun , Kwak Jeonghun , Lee Changhee
Published: October 2012

The effect of a zinc oxide (ZnO) interfacial layer on the device performance of polymer solar cells based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was studied. When a 15 nm ZnO layer was inserted between the active layer (P3HT:PCBM) and Al electrode, the power conversion efficiency (PCE) was increased by approximately 10% as compared to that without ZnO layer. From the systematic analysis of the current–voltage and impedance characteristics of devices with and without the ZnO layer at various temperatures and light intensities, we found that the device with the ZnO layer has a lower activation energy for carrier extraction and bimolecular recombination loss compared with that without the ZnO layer. Therefore, the enhanced efficiency of the device with ZnO is mainly attributed to the enhanced extraction efficiency and thereby increased short-circuit current density.
Electrospray-Deposited Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) for Poly(3-hexylthiophene):Phenyl-C61-Butyric Acid Methyl Ester Photovoltaic Cells
Authors: Hiate Taiga , Ino Tomohisa , Ishikawa Ryo , Ueno Keiji , Shirai Hajime
Published: October 2012

Electrospray-deposited poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was investigated using several solvent solutions as a hole-transporting layer for spin-coated poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61 butyric acid methyl ester (P3HT:PCBM) mixture organic thin-film solar cells (OSCs). Among them, the uniform deposition of PEDOT:PSS films was realized using 70% N,N-dimethylformamide solvent solution. The P3HT:PCBM solar cells with electrospray-deposited PEDOT:PSS as a hole transport layer showed a relatively high performance with an open-circuit voltage V
oc of 0.47 V, a short-circuit current J
sc of 8.9 mA/cm2, a fill factor FF of 0.48, and a power conversion efficiency of 2.0%, which were almost the same as those with a spin-coated PEDOT:PSS layer. These findings imply that the electrospray-deposited PEDOT:PSS is a possible material for use as a hole transport layer for conjugated polymer-based OSCs.
Density Functional Theory Study on Interaction of Hydroperoxyl Radical with Graphene Surface
Authors: Fukuzumi Takahiro , Tachikawa Hiroto
Published: October 2012

The interaction of hydroperoxyl radical (OOH) with a graphene surface has been investigated by means of density functional theory (DFT) method in order to elucidate the radical scavenge mechanism of graphene surface. The OOH radical is highly reactive and the radical plays an important part of materials chemistry. The DFT calculation showed that the OOH radical binds to the carbon atom of graphene surface and a strong C–O bond is formed. The binding energies were dependent on the cluster size and were distributed in the range 18–25 kcal/mol at the B3LYP/6-31G(d) level of theory. The potential energy curve plotted as a function of C–OOH bond distance showed that the OOH radical approaches to the carbon atom with an activation barrier (the barrier height is distributed in 20–25 kcal/mol). Also, it was found that structural change from sp2 to sp3-like hybridization occurs by the approach of OOH.
A Density Functional Theory Study of Interaction of Fluorinated Ethylene Carbonate with a Graphene Surface
Authors: Abe Shigeaki , Watari Fumio , Tachikawa Hiroto
Published: October 2012

The interaction between fluorinated ethylene carbonate denoted by EC(F) and a graphene surface was investigated using of density functional theory (DFT) method. The interaction system examined was a complex composed of graphene (consisting of 14 benzene rings) and one EC(F) molecule. Ten binding sites of EC(F) binding site on the surface and edge regions of the graphene, were identified as stable points. EC(F) bound to a hexagonal position corresponding to the central of benzene ring on the graphene surface and can also bind to the edge of the graphene. The EC(F) binding energies on the surface and edge sides were 0.5 and 2.8 kcal/mol, respectively. The activation barrier for the diffusion of EC(F) on the graphene surface was significantly low (less than 0.3 kcal/mol), indicating that EC(F) can move freely on the graphene surface.
Failure Assessments for Outside-Exposed Photovoltaic Modules
Authors: Shimizu Shigenori , Arai Takashi , Sagawa Tomohiko , Aoki Yuichi , Hirakawa Takumi , Hiraike Hiroshi , Hamamoto Shiro , Sakamoto Sadao , Doi Takuya , Masuda Atsushi , Yamamichi Masaaki
Published: October 2012

Photovoltaic modules with single-crystalline silicon cells and multi-crystalline silicon cells, which were exposed outside for over nine years from 1992, have been evaluated for their failures. Current–voltage characteristic, electroluminescence, and thermography (dark mode) measurement of the modules were carried out as well as those of each solar cell in the modules. Application of these measurements in combination has been shown to be beneficial for investing the failure positions and failure factors in the modules. A new method of analyzing the positions of interconnection failures in modules was also adopted in the present study that is by using electroluminescence measurement and by connecting wires to the interconnector of each individual solar cell.
Microscopic Degradation Mechanisms in Silicon Photovoltaic Module under Long-Term Environmental Exposure
Authors: Matsuda Keiko , Watanabe Takeshi , Sakaguchi Koichi , Yoshikawa Masanobu , Doi Takuya , Masuda Atsushi
Published: October 2012

We used several analytical methods to identify the mechanism underlying the performance degradation in a photovoltaic (PV) module subjected to long-term (10 years) field exposure. Cloudy visual defects in this module were caused by delamination between the poly(ethylene vinyl acetate) (EVA) and antireflection coating films on the Si substrate. The delamination was considered to be caused by the formation of a segregation layer and oxidative degradation of EVA. Furthermore, it was found that sodium ions diffused from the superstrate glass into the EVA film and Si cell. We confirm that diffusion of sodium ions caused the degradation of Si cells and the superstrate glass of this module.
Investigation of the Performance of Commercial Photovoltaic Modules under Tropical Conditions
Authors: Reindl Thomas , Ouyang Jieer , Khaing Aung Myint , Ding Kun , Khoo Yong Sheng , Walsh Timothy M. , Aberle Armin G.
Published: October 2012

The tropical regions will see an increasing share of solar photovoltaic (PV) applications. This paper therefore analyses the irradiance distribution in tropical Singapore and then experimentally determines the dependence of the PV efficiency on irradiance level, for nine different commercially available PV module technologies. For several of the PV module technologies, we also determine the dependence of the temperature coefficient of the modules' maximum power on the irradiance level. A full year of outdoor module testing data in Singapore show that the irradiance distribution has two energy peaks, one at around 400 W·m-2 and the second at around 850 W·m-2. Most PV technologies cannot fully convert the second peak due to the fact that, in Singapore, high light intensities are always associated with higher module temperatures, which in turn reduces the module efficiencies.
Measuring Method of Moisture Ingress into Photovoltaic Modules
Authors: Miyashita Masanori , Kawai Shinji , Masuda Atsushi
Published: October 2012

The reliability of photovoltaic (PV) modules is related to the ingress of moisture in some cases. We investigated the measurement method of moisture ingress into PV modules. In order to detect the moisture ingress route into the module, cobalt chloride (CoCl2) paper was used. The change in the color of CoCl2 paper is effective in detecting and quantifying moisture ingress. The results suggested that the main route of moisture ingress is along the back material and moisture gradually diffuses to the center of the cell. The rate of moisture ingress into the PV module depends on the water–vapor transmission rate (WVTR) of the back material. The amount of moisture estimated from a calibration curve is correlated to the amount of moisture calculated from the WVTR of the back material.
Dielectric Properties of Layered ZnTa2O6/Poly(tetrafluoroethylene) Composites
Authors: Jeon Chang Jun , Kim Eung Soo
Published: October 2012

The effects of ZnTa2O6 content and layered structure on the dielectric properties of ZnTa2O6/poly(tetrafluoroethylene) (PTFE) composites were investigated at microwave frequency. With increasing ZnTa2O6 content, the dielectric constant (K) and dielectric loss (tan
δ) of the composites increased due to the K values of the individual components and the microstructure. For the composites with layered structures, tan
δ was dependent on the internal strain of the composites. Several types of theoretical models were employed to predict the effective K of the composites and the predicted values were compared with experimental data. The temperature coefficient of resonant frequency (TCF) was also discussed as it characterises the thermal stability of the composites. Typically, K of 4.24, tan
δ of 1.36 ×10-3 and, TCF of 4.75 ppm/°C were obtained for the single layered PTFE composites with 0.2 volume fraction (V
f) of ZnTa2O6.
Vacancy-Type Defects Introduced by Gas Cluster Ion-Implantation on Si Studied by Monoenergetic Positron Beams
Authors: Uedono Akira , Moriya Tsuyoshi , Tsutsui Takuro , Kimura Shogo , Oshima Nagayasu , Suzuki Ryoichi , Ishibashi Shoji , Matsui Hidefumi , Narushima Masaki , Ishikawa Yoichi , Graf Michael , Yamashita Koji
Published: October 2012

Vacancy-type defects in Ar and B gas cluster ion-implanted Si were probed by monoenergetic positron beams. The acceleration energy of the clusters ranged between 20–60 keV, and the mean cluster size was 2×103 atoms. Doppler broadening spectra of the annihilation radiation were measured, and the vacancy-rich region was found to localize at a depth of 0–13 nm. Measurements of the lifetime spectra of positrons revealed that two different defect species coexisted in the damaged region introduced by Ar gas cluster implantation, and these were identified as divacancy-type defects and large vacancy clusters filled with Ar. The formation of the vacancy clusters was attributed to extremely high temperature and its rapid transients in impact regions of Ar cluster ions. For B gas cluster ion implanted Si, the detected momentum distribution of electrons in the damaged region was broader than that in the defect free Si, suggesting that the trapping of positrons by open spaces adjacent of B clusters.
Wavelength-Scanning Method for Identifying Vertical Position of Film Using Surface Plasmon Microscopes
Authors: Watanabe Koyo , Matsuura Koji
Published: October 2012

A wavelength-scanning method is proposed to enable surface plasmon microscopes (SPMs) to determine the vertical position of a film. Currently, it is not possible for SPMs to spatially resolve the vertical position of a layer in a multilayered sample structure because the measured value is the effective refractive index (a weighted average of the different refractive indices over the entire sensing volume). We theoretically demonstrate that the vertical position of a layer can be estimated by exploiting the fact that the sensitivity of the effective refractive index depends on the distance from the substrate surface and the wavelength.
Preparation of YBa2Cu3O7-δ Patterned Film Using Metal Organic Deposition with Electron Beam Irradiation
Authors: Tanabe Daiji , Tsukada Kenich , Yamaguchi Iwao , Manago Takashi
Published: October 2012

A microfabrication method to produce YBa2Cu3O7-δ (YBCO) was investigated using the metal organic deposition (MOD) process with electron beam (EB) irradiation. EB irradiation causes decomposition of the C–H and –COO– bonds and desorption of oxygen atoms in the metal octylate precursors. Therefore, oxidation of metal atoms could become harder for the MOD with EB irradiation than for the conventional MOD because of lack of oxygen, and consequently a longer prefiring time is required to ensure oxidation of the metal atoms. Additionally, the heating rate for crystallization was increased to improve film coverage. Finally YBCO film with superconductivity was successfully obtained.
Photoluminescence of Nanocrystalline Silicon Quantum Dots with Various Sizes and Various Phosphorus Doping Concentrations Prepared by Very High Frequency Plasma
Authors: Someno Ken , Usami Kouichi , Kodera Tetsuo , Kawano Yukio , Hatano Mutsuko , Oda Shunri
Published: October 2012

Nanocrystalline silicon quantum dots (nc-Si QDs) with various sizes and various doping concentrations were fabricated by supplying different flow rates of silane (SiH4) gas and phosphine (PH3) gas, respectively, under very high frequency (VHF; 144 MHz) plasma. With an increase in the flow rate of SiH4 gas, the mean size of nc-Si QDs decreases, and photoluminescence (PL) measurements and time-resolved photoluminescence (TRPL) measurements confirm that the quantum confinement becomes weaker. For a small amount of doping PH3 gas, termination of dangling bonds at the interface between the crystal core and the oxide shell in the nc-Si QDs could be supposed on the basis of PL and TRPL measurements. In contrast, for a large amount of doping PH3 gas, Auger recombination could dominate the luminescence properties of nc-Si QDs, and it could decrease the PL intensity and shorten the TRPL decay lifetime.
Simplified Model Involving Energy Balance Mechanism for Atmospheric-Pressure Plasma Plume Generated in Quartz Tube
Authors: Chen Longwei , Zuo Xiao , Wei Yu , Fang Shidong , Cong Jie , Meng Yuedong
Published: October 2012

To unveil the different stages and the inner formation mechanisms for a single-electrode atmospheric-pressure plasma plume generated in a long quartz tube, a simplified positive streamer model including the energy balance mechanism was developed. Numerical results indicated that the applied voltage determines the peak energy gain, and the peak number of ions involved in the streamer tip, and therefore determines the plasma plume length. The variation of plasma plume length with applied voltage, and the average breakdown electric field intensity versus plasma plume length indicate a qualitatively good agreement with the former experimental results.
Investigation of Vertical Channel Architecture for Bulk Erase Operation in Three-Dimensional NAND Flash Memory
Authors: Lee Gae-Hun , Kim Kyeong-Rok , Yang Hyung Jun , Park Sung-Kye , Cho Gyu-Seog , Choi Eun-Seok , Song Yun-Heub
Published: October 2012

A bit-cost scalable (BiCS) technology using a bulk erasing method instead of the conventional erase operation using gate-induced drain leakage (GIDL) is proposed to realize better cell characteristics and process feasibility for three-dimensional (3D) NAND flash memory. This has an additional electrode layer for a bulk erase operation in the middle of a vertical string cell. Here, we confirmed that this structure using an additional electrode provides good program and erasing speed by simulation. Furthermore, junction engineering is performed to realize a polysilicon layer of the flat plate type as a bulk electrode for better design feasibility. From this result, we expect that a bulk erasable BiCS technology using a flat plate erase electrode can be a candidate 3D NAND flash memory technology.
Spray Coating Deposition of Thin Resist Film on Fiber Substrates
Authors: Uchiyama Shogo , Hayase Masanori , Takagi Hideki , Itoh Toshihiro , Zhang Yi
Published: October 2012

In this work, we present extensive investigations on the spray coating process of fiber substrates for microelectromechanical systems (MEMS) applications by using a newly developed spray-coating system. We have examined major parameters of the spray-coating process including the real-time heating treatment, the concentration of the thinner solvent, the nozzle/substrate distance, and the diameter and rotation speed of the fiber substrate. It was found that the spray-coating process of the fibers was dependent on their diameters. When the fiber diameter was 300 µm or larger, the spray-coating process was similar to those of conventional semiconductor wafers. For example, the resist film became thinner with either a larger diameter or a higher rotation speed of the fiber substrate because of the larger centrifugal force. When the fiber diameter was 125 µm, the spray-coating process exhibited different behavior. For example, the spreading of spray droplets was good and the whole surface of the fiber substrate was almost covered by resist film even without the substrate rotation. The real-time heating treatment also played a significant role during the spray-coating process of the 125-µm-diameter fiber. The spray-deposited film became even thicker with the increasing concentration of the thinner solvent, which mainly resulted from the fact that the fiber had a low heat capacity and a high-topography surface.
Fluid flow through porous sandstone with overprinting and intersecting geological structures of various types
Authors: Zhou Xiaoxian , Karimi-Fard Mohammad , Durlofsky Louis J. , Aydin Atilla
Published: October 2012

It is well established that compaction bands (CBs), joints and faults are often present in the same rock volume in the Jurassic aeolian Aztec Sandstone, exposed in the Valley of Fire State Park, Nevada, USA. Because the permeability of CBs can be one or more orders of magnitude less than the matrix permeability, and joint permeability, depending on its aperture, can be several orders of magnitude greater than matrix permeability, the combined effect of these structures on subsurface flow can be complex and substantial. In this study, we investigate the effects of a variety of intersecting geological structures on fluid flow. This is accomplished by performing two- (2D) and three-dimensional (3D) permeability upscaling and waterflood simulations over areas/volumes populated by hydraulically interacting geological features. The regions considered are approximately the size of typical grid blocks used for reservoir or aquifer flow simulations, so the results are of practical interest. The systems studied include models with two sets of vertical CBs intersecting at various angles, an inclined CB set intersecting a vertical CB set, a joint set intersecting a CB set at various angles, and a small fault and its damage zone overprinting a CB set. Our numerical results quantify the impact of these composite structures on subsurface flow and show, for example, that the intersection angle of two sets of structures can have a considerable effect on the upscaled directional permeability. In addition, waterflood simulations demonstrate that the efficiency of oil recovery can be significantly impacted by the direction of flow relative to the orientation of intersecting geological structures.
The research value of publishing attacks
Authors: Basin David , Capkun Srdjan
Published: October 2012

Security research can be improved by more effectively sharing what is learned from attacks on information systems.
Decentralization versus centralization in IT governance
Authors: McElheran Kristina
Published: October 2012

It's not as simple as you might think.
Disks from the perspective of a file system
Authors: Mckusick Marshall Kirk
Published: October 2012

Disks lie. And the controllers that run them are partners in crime.
Measuring home broadband performance
Authors: Sundaresan Srikanth , de Donato Walter , Feamster Nick , Teixeira Renata , Crawford Sam , Pescapè Antonio
Published: October 2012

We present the results from the first study of Internet access link performance measured directly from home routers. In conjunction with the Federal Communication Commission's study of broadband Internet access in the United States, we investigate the throughput and latency of network access links from about 4000 routers across eight ISPs. Our findings provide a snapshot of access network performance across the United States, offer insights on how access network performance should be measured and presented to users, and inform various ongoing efforts to evaluate the performance of access networks around the world.
Towards a navigation system for blind people
Authors: Poláček Ondřej , Grill Thomas , Tscheligi Manfred
Published: October 2012

In this paper, we present an initial study towards of an indoor navigation system for blind people. As the system itself is still in an early stage of development, we conducted a Wizard of Oz study using a generic Wizard of Oz system designed for mobile and ubiquitous studies. The goal of the study was to validate a set of audio-based navigation commands in a field study context. Further, we wanted to identify usability issues of the Wizard of Oz tool, and ensure the appropriateness of the addressed study setup. Therefore, we used eight human wizards as participants in the study. Their task was to guide two blindfolded actors through a predefined route. Such settings helped us to achieve high ecological validity of the results compared to laboratory testing. We found that the developed study setup is fully mobile and can be used in any mobile context, the voice commands chosen for navigation are almost complete, and can be used with slight modifications for the follow-up study. Additionally we identified several usability flaws of the Wizard of Oz tool. After implementing the findings, the tool and the study setup are ready for a follow-up study with blind persons in order to validate the selected voice commands in depth.
On the Perturbation Bounds of Projected Generalized Continuous‐Time Sylvester Equations
Authors: Zhou Yujian , Bao Liang , Lin Yiqin
Published: October 2012

This paper is devoted to the perturbation analysis for a projected generalized continuous‐time Sylvester equation. Perturbation bounds of the solution based on the Euclidean norm are presented.
A Simulation of the Effects of Varying Repetition Rate and Pulse Width of Nanosecond Discharges on Premixed Lean Methane-Air Combustion
Authors: Bak Moon Soo , Cappelli Mark A.
Published: October 2012

Two-dimensional kinetic simulation has been carried out to investigate the effects of repetition rate and pulse width of nanosecond repetitively pulsed discharges on stabilizing premixed lean methane-air combustion. The repetition rate and pulse width are varied from 10 kHz to 50 kHz and from 9 ns to 2 ns while the total power is kept constant. The lower repetition rates provide larger amounts of radicals such as O, H, and OH. However, the effect on stabilization is found to be the same for all of the tested repetition rates. The shorter pulse width is found to favor the production of species in higher electronic states, but the varying effects on stabilization are also found to be small. Our results indicate that the total deposited power is the critical element that determines the extent of stabilization over this range of discharge properties studied.
A Dual-Band SiGe HBT Frequency-Tunable and Phase-Shifting Differential Amplifier Employing Varactor-Loaded, Stacked LC Resonators
Authors: Sakamoto Kazuyoshi , Itoh Yasushi
Published: October 2012

A dual-band SiGe HBT frequency-tunable and phase-shifting differential amplifier has been developed for the future active phased array antennas with a multiband, multibeam, and multitarget tracking operation. The amplifier uses varactor-loaded, stacked LC resonators in the design of the output circuit in order to provide frequency-tunable and phase-shifting capabilities for dual frequencies. By utilizing the varactor-loaded LC resonator, which has a variable resonant frequency and a large insertion phase variation, frequency-tunable and phase-shifting performances become available. Moreover, by using the stacked configuration, the frequency and insertion phase can be varied independently for dual frequencies. A dual-band SiGe HBT differential amplifier has achieved a lower-frequency tuning range of 0.56 to 0.7 GHz for a higher fixed frequency of 0.97 GHz as well as a higher-frequency tuning range of 0.92 to 1.01 GHz for a lower fixed frequency of 0.63 GHz. A lower-frequency phase variation of 99° and a higher-frequency phase variation of 90.3° have been accomplished at 0.63 and 0.97 GHz, respectively. This is the first report on the dual-band differential amplifier with frequency-tunable and phase-shifting capabilities.
Slider Posture Effects on Air Bearing in a Heat-Assisted Magnetic Recording System
Authors: Myo Kyaw Sett , Zhou Weidong , Huang Xiaoyang , Yu Shengkai , Hua Wei
Published: October 2012

This paper reports the effects of slider posture on the slider bearing in a heat-assisted magnetic recording (HAMR) system with the direct simulation Monte Carlo (DSMC) method. In this HAMR system, the heat issues on the slider bearings are assumed to be caused by a heated spot on the disk and/or slider body itself at various pitch angles. The simulation results show that with a heated spot on the disk, the air bearing pressure and air bearing force that acted on the slider surface will increase when the pitch angle becomes larger. It is also found that the bearing force increases with the heated spot size and the effects of a heated spot become more obvious at a larger pitch angle. On the other hand, the slider body temperature is observed to have a noticeable effect on air bearing pressure and force. The smaller pitch angle enlarges the tendency of bearing force variations with the slider temperature and makes the slider more sensitive to its temperature changes.
Facile Synthesis of Porous‐Structured Nickel Oxide Thin Film by Pulsed Laser Deposition
Authors: Pilban Jahromi Siamak , Huang Nay Ming , Kamalianfar Ahmad , Lim Hong Ngee , Muhamad Muhamad Rasat , Yousefi Ramin
Published: October 2012

Porous‐structured nickel oxide (PsNiO) was obtained through the oxidization of a nickel thin film. The nickel thin film was deposited using the pulsed laser deposition (PLD) method on a nickel foil as a substrate. The results show uniform PsNiO after the oxidization of the nickel thin film at 750∘C for 1 h. X‐ray diffraction (XRD) indicates formation of the NiO crystalline structure. Field emission scanning electron microscopy (FESEM) reveals different morphology on the surface of the nickel foil (sample A) and on the nickel thin film (sample B). Comparison of the FESEM results after oxidization shows that the PsNiO on the nickel thin film was more regular and controllable than the NiO layer on the nickel foil. The FESEM images also show that the thickness of the nickel thin film affected the PsNiO size obtained after oxidization. This resulted from the growth of the porous structure at grain boundaries and from the grain sizes. The electrochemical properties of the PsNiO as an electrode are investigated by cyclic voltammetry (CV). These results show the effect of PsNiO size on the current of anodic peak.
Secondary Hip Osteoarthritis due to Neurofibroma Treated with Total Hip Replacement
Authors: Tangsataporn Suksan , Shakib Alireza , Kuzyk Paul R. , Backstein David J. , Gross Allan E. , Safir Oleg A.
Published: October 2012

Background. Local plexiform neurofibroma can lead to deformity of the pelvis, valgus deformity of femoral neck, and joint capsule laxity. We report a case of secondary hip osteoarthritis with subluxation and coxa vara deformity resulting from an extra-articular neurofibroma treated with total hip replacement.Case Description. A 39-year-old man had a large benign plexiform neurofibroma at buttock which induced secondary osteoarthritis of the hip. Conservative treatment of tumor was selected because the patient had low chance of malignant transformation due to absence of other neurofibromatosis features. However, due to secondary osteoarthritis he underwent total hip arthroplasty. Anterior capsulotomy was selected to avoid large posterior hip tumor mass. In order to avoid the difficulties associated with setting tension of the abductor muscle, modified trochanteric slide osteotomy with trochanteric advancement, lateralized cup placement, and extended neck offset were used. One year after the surgery, the patient had excellent clinical function, hip stability, leg length equality and was satisfied with the outcome.Clinical Relevance. We concluded that the modified trochanteric slide osteotomy with trochanteric advancement represents a valuable approach for THR in patients with extremely elongation of the hip abductor and secondary hip osteoarthritis resulting from extra-articular neurofibroma.
A Theoretical Investigation of the Ring Strain Energy, Destabilization Energy, and Heat of Formation of CL-20
Authors: Bumpus John A.
Published: October 2012

The cage compound CL-20 (a.k.a., 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, HNIW, or 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.03,11.05,9]dodecane) is a well-studied high-energy-density material (HEDM). The high positive gas- (ΔfHg°) and solid- (ΔfHs°) phase heat of formation values for CL-20 conformers have often been attributed to the strain energy of this cage compound and, by implication, to the conventional ring strain energy (CRSE) inherent in isowurtzitane which may be viewed as a “parent compound” (although not the synthetic precursor) of CL-20. ΔfHg° values and destabilization energies (DSEs), which include the contribution from CRSE, were determined by computation using a relatively new multilevel ab intio model chemistry. Compared to cubane, isowurtzitane does not have an exceptionally high CRSE. It is about the same as that of cyclopropane and cyclobutane. These investigations demonstrate that instead of the CRSE inherent in the isowurtzitane parent compound, the relatively high ΔfHg° and DSE values of CL-20 conformers must be due, primarily, to torsional strain (Pitzer strain), transannular strain (Prelog strain), and van der Waals interactions that occur due to the presence of the six >N–NO2 substituents that replace the six methylene (–CH2–) groups in the isowurtzitane parent compound. These conclusions are even more pronounced when 2,4,6,8,10,12-hexaazaisowurtzitane is viewed as the “parent compound.”
Spontaneous Ovarian Hyperstimulation Syndrome in a Triplet Pregnancy
Authors: Agrawal Nisha Rani , Gupta Garima , Verma Kusum , Varyani Neeraj
Published: October 2012

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening complication, usually iatrogenic after ovulation induction. OHSS is a very rare event in spontaneously conceived pregnancies. Only few cases have been reported in literature to the best of our knowledge. We report a very rare case of spontaneous critical OHSS (according to classification of severity of OHSS as mentioned in Greentop guidelines no. 5, 2006) associated with triplet pregnancy in a 26-year-old woman suffering from severe abdominal pain, distension, and dyspnea. Our case highlights the importance of a strong suspicion for OHSS when a clinical presentation could not be explained by common medical conditions.
Isolated Torticollis May Present as an Atypical Presentation of Meningitis
Authors: Chirurgi Roger , Kahlon Samrina
Published: October 2012

Background. Bacterial meningitis is a life-threatening medical emergency that requires urgent diagnosis and treatment. Diagnosis is infrequently missed if the patient presents with the classic symptoms of fever, headache, rash, nuchal rigidity, or Kernig or Brudzinski sign. However, it may be less obvious in neonates, elderly, or immunocompromised patients. Meningitis which presents as isolated torticollis, without any other signs or symptoms, is exceedingly rare.Objective. To identify an abnormal presentation of meningitis in an adult immunocompromised patient.Case Report. We present a case of an adult diabetic male who presented multiple times to the ED with complaint of isolated torticollis, who ultimately was diagnosed with bacterial meningitis.Conclusion. We propose that in the absence of sufficient explanation for acute painful torticollis in an immunocompromised adult patient, further evaluation, possibly including a lumbar puncture may be warranted.
Dioxaphosphorinane-Constrained Nucleic Acid Dinucleotides as Tools for Structural Tuning of Nucleic Acids
Authors: Catana Dan-Andrei , Renard Brice-Loïc , Maturano Marie , Payrastre Corinne , Tarrat Nathalie , Escudier Jean-Marc
Published: October 2012

We describe a rational approach devoted to modulate the sugar-phosphate backbone geometry of nucleic acids. Constraints were generated by connecting one oxygen of the phosphate group to a carbon of the sugar moiety. The so-called dioxaphosphorinane rings were introduced at key positions along the sugar-phosphate backbone allowing the control of the six-torsion anglesαtoζdefining the polymer structure. The syntheses of all the members of the D-CNA family are described, and we emphasize the effect on secondary structure stabilization of a couple of diastereoisomers ofα,β-D-CNA exhibiting wether B-type canonical values or not.
Effects of Puerariae Radix Extract on Endotoxin Receptors and TNF-αExpression Induced by Gut-Derived Endotoxin in Chronic Alcoholic Liver Injury
Authors: Peng Jing-Hua , Cui Tuan , Sun Zhao-Lin , Huang Fu , Chen Liang , Xu Lin , Feng Qin , Hu Yi-Yang
Published: October 2012

Kudzu (Pueraria lobata) is one of the earliest medicinal plants used to treat alcohol abuse in traditional Chinese medicine for more than a millennium. However, little is known about its effects on chronic alcoholic liver injury. Therefore, the present study observed the effects of puerariae radix extract (RPE) on chronic alcoholic liver injury as well as Kupffer cells (KCs) activation to release tumor necrosis factor alpha (TNF-α) induced by gut-derived endotoxin in rats and macrophage cell line. RPE was observed to alleviate the pathological changes and lipids deposition in liver tissues as well as the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic gamma-glutamyl transpeptidase (GGT) activity. Meanwhile, RPE inhibited KCs activation and subsequent hepatic TNF-αexpression and downregulated the protein expression of endotoxin receptors, lipopolysaccharide binding protein (LBP), CD14, Toll-like receptor (TLR) 2, and TLR4 in chronic alcohol intake rats. Furthermore, anin vitrostudy showed that RPE inhibited the expression of TNF-αand endotoxin receptors, CD14 and TLR4, induced by LPS in RAW264.7 cells. In summary, this study demonstrated that RPE mitigated liver damage and lipid deposition induced by chronic alcohol intake in rats, as well as TNF-αrelease, protein expression of endotoxin receptorsin vivoorin vitro.
The Contribution of Allergen-Specific IgG to the Development of Th2-Mediated Airway Inflammation
Authors: Williams Jesse W. , Tjota Melissa Y. , Sperling Anne I.
Published: October 2012

In both human asthmatics and animal models of allergy, allergen-specific IgG can contribute to Th2-mediated allergic inflammation. Mouse models have elucidated an important role for IgG and Fc-gamma receptor (FcγR) signaling on antigen presenting cells (APC) for the induction of airway inflammation. These studies suggest a positive feedback loop between IgG produced by the adaptive B cell response and FcγR signaling on innate immune cells. Studies of IgG and FcγRs in humans with asthma or allergic lung disease have been more controversial. Some reports have identified associations between allergen-specific IgG and severity of allergic responses, while other studies have found associations of IgG subclass IgG4 with allergic tolerance. In this paper, we review the literature to help define the nature of IgG and FcγR signaling on innate immune cells and how it contributes to the development of allergic immune responses.
Transitions among Health States Using 12 Measures of Successful Aging in Men and Women: Results from the Cardiovascular Health Study
Authors: Thielke Stephen , Diehr Paula
Published: October 2012

Introduction. Successful aging has many dimensions, which may manifest differently in men and women at different ages.Methods. We characterized one-year transitions among health states in 12 measures of successful aging among adults in the Cardiovascular Health Study. The measures included self-rated health, ADLs, IADLs, depression, cognition, timed walk, number of days spent in bed, number of blocks walked, extremity strength, recent hospitalizations, feelings about life as a whole, and life satisfaction. We dichotomized variables into “healthy” or “sick,” states, and estimated the prevalence of the healthy state and the probability of transitioning from one state to another, or dying, during yearly intervals. We compared men and women and three age groups (65–74, 75–84, and 85–94).Findings. Measures of successful aging showed similar results by gender. Most participants remained healthy even into advanced ages, although health declined for all measures. Recuperation, although less common with age, still occurred frequently. Men had a higher death rate than women regardless of health status, and were also more likely to remain in the healthy state.Discussion.The results suggest a qualitatively different experience of successful aging between men and women. Men did not simply “age faster” than women.
Canine Mammary Mixed Tumours: A Review
Authors: Dantas Cassali Geovanni , Cavalheiro Bertagnolli Angélica , Ferreira Enio , Araújo Damasceno Karine , de Oliveira Gamba Conrado , Bonolo de Campos Cecília
Published: October 2012

Mammary mixed tumours are the most frequent neoplasias in female dogs. In humans, mixed tumours are frequently found in the salivary glands and are known as pleomorphic adenomas. In addition to their histomorphologic similarities, mixed tumours and pleomorphic adenomas have the potential to become malignant and give rise to carcinomas in mixed tumours and carcinomas ex-pleomorphic adenoma, respectively. The factors associated with malignant transformation are still poorly known in the case of canine mixed tumours. However, this form of neoplasia tends to be associated with a better prognosis than other malignant histological types. This paper discusses the main features associated with female canine mammary mixed tumours.
A Successive Linearization Method Approach to Solve Lane‐EmdenType of Equations
Authors: Motsa S. S. , Shateyi S.
Published: October 2012

We propose a new application of the successive linearization method for solving singular initial and boundary value problems of Lane‐Emden type. To demonstrate the reliability of the proposed method, a comparison is made with results from existing methods in the literature and with exact analytical solutions. It was found that the method is easy to implement, yields accurate results, and performs better than some numerical methods.
Postthyroidectomy Horner’s Syndrome
Authors: Vilallonga Ramon , Fort José Manuel , Mazarro Alejandro , Gonzalez Oscar , Caubet Enric , Romero Giancarlo , Armengol Manel
Published: October 2012

Horner’s syndrome (HSd) results from an injury along the cervical sympathetic chain, producing ipsilateral miosis, ptosis, enophthalmos, and facial anhydrosis. Although more commonly associated to malignant tumors affecting the preganglionar segment of the sympathetic chain (especially in the lung apex), HSd has been described as a rare complication of thyroid surgery. We herein report a case of HSd after completing total thyroidectomy.
Leptospiraand Inflammation
Authors: Gonçalves-de-Albuquerque C. F. , Burth P. , Silva A. R. , Younes-Ibrahim M. , Castro-Faria-Neto H. C. , Castro-Faria M. V.
Published: October 2012

Leptospirosis is an important zoonosis and has a worldwide impact on public health. This paper will discuss both the role of immunogenic and pathogenic molecules during leptospirosis infection and possible new targets for immunotherapy against leptospira components.Leptospira, possess a wide variety of mechanisms that allow them to evade the host immune system and cause infection. Many molecules contribute to the ability ofLeptospirato adhere, invade, and colonize. The recent sequencing of theLeptospiragenome has increased our knowledge about this pathogen. Although the virulence factors, molecular targets, mechanisms of inflammation, and signaling pathways triggered by leptospiral antigens have been studied, some questions are still unanswered. Toll-like receptors (TLRs) are the primary sensors of invading pathogens. TLRs recognize conserved microbial pattern molecules and activate signaling pathways that are pivotal to innate and adaptive immune responses. Recently, a new molecular target has emerged—the Na/K-ATPase—which may contribute to inflammatory and metabolic alteration in this syndrome. Na/K-ATPase is a target for specific fatty acids of host origin and for bacterial components such as the glycolipoprotein fraction (GLP) that may lead to inflammasome activation. We propose that in addition to TLRs, Na/K-ATPase may play a role in the innate response to leptospirosis infection.
The MAPK MEK1/2-ERK1/2 Pathway and Its Implication in Hepatocyte Cell Cycle Control
Authors: Guégan Jean-Philippe , Frémin Christophe , Baffet Georges
Published: October 2012

Primary cultures of hepatocytes are powerful models in studying the sequence of events that are necessary for cell progression from a G0-like state to S phase. The models mimic the physiological process of hepatic regeneration after liver injury or partial hepatectomy. Many reports suggest that the mitogen-activated protein kinase (MAPK) ERK1/2 can support hepatocyte proliferationin vitroandin vivoand the MEK/ERK cascade acts as an essential element in hepatocyte responses induced by the EGF. Moreover, its disregulation has been associated with the promotion of tumor cell growth of a variety of tumors, including hepatocellular carcinoma. Whereas the strict specificity of action of ERK1 and ERK2 is still debated, the MAPKs may have specific biological functions under certain contexts and according to the differentiation status of the cells, notably hepatocytes. In this paper, we will focus on MEK1/2-ERK1/2 activations and roles in normal rodent hepatocytesin vitroand in vivo after partial hepatectomy and in human hepatocarcinoma cells. The possible specificity of ERK1 and ERK2 in normal and transformed hepatocyte will be discussed in regard to other differentiated and undifferentiated cellular models.