bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual‐Band Wlan Antenna Design by Controlling Higher Order Mode Characteristic
Authors: Yu Jaekyu , Zhang Rui , Liu Yang , Kim Hyung‐Hoon , Kim Hyeongdong 
Published: May 2013

ABSTRACTThis article presents a new method for designing a dual‐band WLAN antenna using the higher order harmonic mode of a monopole antenna, the first‐order mode of which operates at the low‐frequency band of WLAN (2.4 GHz). After measuring the current distribution in the higher order antenna mode, we added a stub in a location where the electric field is strong. This added stub brought the resonant frequency into the higher WLAN frequency band. Further, the input impedance was controlled by controlling the width of the branch without affecting the low‐frequency band of the WLAN (the first‐order mode of the monopole antenna). This compact dual‐band antenna was designed to be the size of a universal serial bus dongle, and the −10 dB bandwidths are 700 MHz (2.3–3 GHz) at 2 GHz and 1 GHz (4.9–5.9 GHz) at 5 GHz, which cover the full WLAN dual bands. The proposed antenna achieves more than 50% efficiency in WLAN bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1897–1902, 2013
Power Divider with Arbitrary Power Ratio and Arbitrary Ripple Level Using Filter Synthesis Techniques
Authors: Zhang Qingfeng , Caloz Christophe 
Published: May 2013

ABSTRACTA novel type of power divider, featuring arbitrary power ratio and arbitrary ripple level, is proposed. This divider consists of a two‐port filtering structure connected to a circulator and is straightforwardly designed using microwave filter synthesis techniques. An example is provided, with low‐pass domain synthesis and experimental divider demonstration at the X‐band, after low‐pass to bandpass transformation. The experimental divider prototype is an iris coupled‐resonator waveguide structure, whose response is found in good agreement with theoretical predictions. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1819–1820, 2013
an 800‐MHz LC‐VCO with a Linear Control Characteristics in a 130‐nm CMOS Technology
Authors: Lee Hui Dong , Jung Jae Ho , Lee Kwang Chun 
Published: May 2013

ABSTRACTA semilinear LC‐voltage‐controlled oscillator (VCO) topology is proposed. To exploit a linear frequency tuning, the LC‐VCO adopts the variable capacitance block of the varactor devices and the PMOS transistors. This block has the capacitance characteristics which are approximately inversely proportional to the square of the VCO control voltage. The proposed LC‐VCO is implemented in a 130‐nm CMOS technology. The measurement results show a semilinear frequency range of 503–873 MHz and a phase noise of −128 dBc/Hz at 1 MHz offset frequency. Power consumption is about 2 mA from a 1.2 V supply. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1972–1975, 2013
Reconfigurable Hexa‐Band Planar Inverted‐F Antenna Using a PIN Diode for Mobile Handset
Authors: Lee Junhyuk H. , Sung Youngje 
Published: May 2013

ABSTRACTA compact, reconfigurable planar inverted‐F antenna (PIFA) for mobile phone applications is presented. Based on recent smart‐phone geometries, a PIN diode on an antenna radiator is used for frequency‐reconfigurable operation with a PIFA structure. The proposed novel hexa‐band built‐in mobile antenna, which is designed to cover LTE, GSM850, GSM900, DCS, PCS, and UMTS bands, is satisfactory in terms of its reflection coefficient, radiation patterns, and average gain (efficiency). A prototype is investigated, and good agreement between simulations and measurements is shown. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1926–1928, 2013
A Dual‐Band Narrow Band‐Pass Filter with Half‐Wavelength Open Stubs Using the CRLH Metamaterial
Authors: Yoon, Ki‐Cheol , Lee Hyun‐Wook , Lee Jong‐Chul , Kim Seong‐Cheol 
Published: May 2013

ABSTRACTA narrow‐bandwidth dual‐band (DB) band‐pass filter (BPF) with λg/2 open stubs constructed using composite right/left‐handed (CRLH) metamaterial transmission lines (TLs) is presented. A conventional narrow BPF with λg/2 open stubs is first designed using series λg/2 open stubs and λg/4 TLs. Then, a DB filter can then be easily implemented by replacing the microstrip lines with the CRLH‐TL unit cells. The DB BPF using the CRLH‐TL unit cell is experimentally demonstrated at dual‐operating frequencies of 5.8 and 10.02 GHz. The experimental results are in good agreement with the simulation results. The DB BPF shows 11 and 13% pass bandwidth at the center frequencies of 5.8 and 10.02 GHz, respectively. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1887–1890, 2013
A Dualband Coupled‐Fed Lte/Wwan Planar Antenna for Mobile Devices
Authors: Sim Chow‐Yen‐Desmond , Chien Yu‐Lun 
Published: May 2013

ABSTRACTA coupled‐fed antenna that combines the long term evolution operation with the wireless wide area network operation is proposed. The antenna is mainly composed of a T‐shaped radiator linked to the ground plane via a narrow meandered line. Good impedance matching throughout all bands of interest is achieved by embedding a C‐shaped coupling structure into the narrow meandered line, followed by protruding a small stub at the right bottom corner (vertical structure) of the T‐shaped radiator. Furthermore, by reconstructing the coupled‐fed structure as a halved‐tapered fed design, two wide operating bands that operate between 680 and 1380 MHz (68%), and 1550 and 2830 MHz (58.4%) are achieved. The process of designing the proposed antenna is explicitly shown, and parametric studies were carried out by simulation. Typical experimental measurements were also conducted and compared to the simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1851–1856, 2013
Compact Wide‐Band Branch‐Line Coupler with Meander Line, Cross, and Two‐Step Stubs
Authors: Sa'ad B. M. , Rahim Sharul K.A. , Dewan Raimi 
Published: May 2013

ABSTRACTDespite being widely used, branch‐line couplers (BLC) still suffer from large size. This makes it difficult to incorporate BLC into miniature microwave devices. The work presented here is the design and implementation of a 3‐dB reduced‐size wide‐band 3‐branch‐line coupler (3‐BLC). By combining meander line, cross, and two‐step stubs techniques, size reduction and bandwidth improvement is successfully achieved on 3‐BLC design. The 3‐BLC length was reduced along the horizontal branches using two‐step reduction technique while the center vertical branch was reduced using cross stubs. A simple two‐turn meander line is utilized at the two ends vertical branches of the coupler to obtain balanced length with the middle vertical branch. Hence, its width was optimized to maximize the coupler bandwidth. The 3‐BLC was designed to operate at 2.45 GHz wireless local area network frequency band (IEEE 802.11 b/g) and fabricated on a 1.6 mm thick FR‐4 board. The simulated and measured results are in very good agreement and show a fractional bandwidth of 50% and a sized reduction of 61.64% at the center of the frequency band. The proposed coupler design provides BLC that occupies less space, simple to implement, and wide‐band BLC architecture with generic 3‐BLC wide‐band characteristics retained. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1810–1815, 2013
Novel Polarization Independent Metamaterial and its Application in Patch Antenna
Authors: Kumar Anand , Kumar V. Dinesh 
Published: May 2013

ABSTRACTWe report a new structure of metamaterial, consisting of an array of double concentric rings and cross stripes of metal film separated by a dielectric layer. Using Finite Integration Technique, its properties are investigated; the metamaterial exhibits left handed behavior for both linear as well as circular polarization. Further the metamaterial is used as a cover to improve the directionality of a rectangular patch antenna using quadrature feed for producing a focused circularly polarized beam at frequency 11 GHz.© 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1963–1969, 2013
ERRATUM: A Novel Low‐Voltage Tunable Capacitor for Tunable RF Circuit Applications
Authors: Chul Lee, Young , Ju Lee Baek , Hyun Ko Kyung 
Published: May 2013

ABSTRACTOriginally published Microwave Opt Technol Lett 55: 1152–1155, 2013. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1976, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27740 (Original article DOI 10.1002/mop.27500)
Simultaneous multislice excitation by parallel transmission
Authors: Poser Benedikt A. , Anderson Robert James , Guérin Bastien , Setsompop Kawin , Deng Weiran , Mareyam Azma , Serano Peter , Wald Lawrence L. , Stenger V. Andrew 
Published: May 2013

PurposeA technique is described for simultaneous multislice (SMS) excitation using radiofrequency (RF) parallel transmission (pTX).MethodsSpatially distinct slices are simultaneously excited by applying different RF frequencies on groups of elements of a multichannel transmit array. The localized transmit sensitivities of the coil geometry are thereby exploited to reduce RF power. The method is capable of achieving SMS‐excitation using single‐slice RF pulses, or multiband pulses. SMS‐pTX is demonstrated using eight‐channel parallel RF transmission on a dual‐ring pTX coil at 3 T. The effect on B1+ homogeneity and specific absorption rate (SAR) is evaluated experimentally and by simulations. Slice‐GRAPPA reconstruction was used for separation of the collapsed slice signals.ResultsPhantom and in vivo brain data acquired with fast low‐angle shot (FLASH) and blipped‐controlled aliasing results in higher acceleration (CAIPIRINHA) echo‐planar imaging are presented at SMS excitation factors of two, four, and six. We also show that with our pTX coil design, slice placement, and binary division of transmitters, SMS‐pTX excitations can achieve the same mean flip angles excitations at ∼30% lower RF power than a conventional SMS approach with multiband RF pulses.ConclusionThe proposed SMS‐pTX allows SMS excitations at reduced RF power by exploiting the local B1+ sensitivities of suitable multielement pTX arrays. Magn Reson Med 71:1416–1427, 2014. © 2013 Wiley Periodicals, Inc.
The perturbation bound for the Perron vector of a transition probability tensor
Authors: Li Wen , Cui Lu‐Bin , Ng Michael K. 
Published: May 2013

SUMMARYIn this paper, we study the perturbation bound for the Perron vector of an mth‐order n‐dimensional transition probability tensor with and . The Perron vector x associated to the largest Z‐eigenvalue 1 of , satisfies where the entries xi of x are non‐negative and . The main contribution of this paper is to show that when is perturbed to an another transition probability tensor by , the 1‐norm error between x and is bounded by m, , and the computable quantity related to the uniqueness condition for the Perron vector of . Based on our analysis, we can derive a new perturbation bound for the Perron vector of a transition probability matrix which refers to the case of m = 2. Numerical examples are presented to illustrate the theoretical results of our perturbation analysis. Copyright © 2013 John Wiley & Sons, Ltd.
Amino, ammonio and aminioethenes: a theoretical study of their structure and energetics
Authors: Miranda Margarida S. , Esteves da Silva Joaquim C. G. , Castillo Alvaro , Frank Aaron T. , Greer Alexander , Brown Jodian A. , Davis Brittny C. , Liebman Joel F. 
Published: May 2013

We have performed high level ab initio quantum mechanical calculations for aminoethene and the three isomeric 1,1‐ (Z)‐ or (E)‐1,2‐diaminoethenes as well as their singly and doubly charged cations derived by loss of electrons and/or upon protonation. Gas phase molecular structures were computed at the MP2/6‐311 + G(3df,2p) level. Standard molar enthalpies of formation in the gas phase, at T = 298.15 K, were estimated using the G3 composite method and atomization, isodesmic and homodesmotic reactions. Other energetic parameters were also calculated at the G3 level: proton affinities, basicities and adiabatic ionization enthalpies.Theoretical and experimental data are compared. The reported experimental data refer only to aminoethene wherein the standard molar enthalpy of formation has a considerable uncertainty, although the molecular structure is well established. There are no such data, neither structural nor thermochemical, for any of the three isomeric diaminoethenes. Isoelectronic comparisons are made. For example, the diprotonated diaminoethenes are isoelectronic to isobutene and (Z)‐ and (E)‐butene, while the doubly ionized diaminoethenes are likewise related to trimethylenemethane and 1,3‐butadiene. Copyright © 2013 John Wiley & Sons, Ltd.
Heat Flux Measurement from Bulk Magnesium/Teflon/Viton (MTV) Flare Composition Combustion
Authors: Williams Michael R. , Dunne Jennifer L. 
Published: May 2013

AbstractRadiant heat output has been measured from an MTV flare composition for masses between 0.2 and 36 kg. Around 30 % of the heat of reaction is lost as radiation. The maximum temperature at the surface of the fireball is estimated to be around 1800 K. The effect of distance on the received radiated heat dose is complex but, with large buoyant fireballs, the attenuation might be as small as the inverse of distance.
Agglomeration Characteristics of Aluminum Particles in AP/AN Composite Propellants
Authors: Takahashi Kenichi , Oide Sho , Kuwahara Takuo 
Published: May 2013

AbstractMost solid rockets are powered by ammonium perchlorate (AP) composite propellant including aluminum particles. As aluminized composite propellant burns, aluminum particles agglomerate as large as above 100 μm diameter on the burning surface, which in turn affects propellant combustion characteristics. The development of composite propellants has a long history. Many studies of aluminum particle combustion have been conducted. Optical observations indicate that aluminum particles form agglomerates on the burning surface of aluminized composite propellant. They ignite on leaving the burning surface. Because the temperature gradient in the reaction zone near a burning surface influences the burning rate of a composite propellant, details of aluminum particle agglomeration, agglomerate ignition, and their effects on the temperature gradient must be investigated. In our previous studies, we measured the aluminum particle agglomerate diameter by optical observation and collecting particles. We observed particles on the burning surface, the reaction zone, and the luminous flame zone of an ammonium perchlorate (AP)/ammonium nitrate (AN) composite propellant. We confirmed that agglomeration occurred in the reaction zone and that the agglomerate diameter decreased with increasing the burning rate. In this study, observing aluminum particles in the reaction zone near the burning surface, we investigated the relation between the agglomerates and the burning rate. A decreased burning rate and increased added amount of aluminum particles caused a larger agglomerate diameter. Defining the extent of the distributed aluminum particles before they agglomerate as an agglomerate range, we found that the agglomerate range was constant irrespective of the added amount of aluminum particles. Furthermore, the agglomerate diameter was ascertained from the density of the added amount of aluminum particles in the agglomerate range. We concluded from the heat balance around the burning surface that the product of the agglomerate range and the burning rate was nearly constant irrespective of the added amount of aluminum particles. Moreover, the reduced burning rate increased the agglomerate range.
On the Reliability of Sensitivity Test Methods for Submicrometer‐Sized RDX and HMX Particles
Authors: Radacsi Norbert , Bouma Richard H. B. , Krabbendam‐la Haye Ellen L. M. , ter Horst Joop H. , Stankiewicz Andrzej I. , van der Heijden Antoine E. D. M. 
Published: May 2013

AbstractSubmicrometer‐sized RDX and HMX crystals were produced by electrospray crystallization and submicrometer‐sized RDX crystals were produced by plasma‐assisted crystallization. Impact and friction sensitivity tests and ballistic impact chamber tests were performed to determine the product sensitivity. Rather than reflecting the quality of the particles, we found the sensitivity tests to be unreliable for submicrometer particles. The used impact test was not accurate enough, while in the friction and ballistic impact chamber tests the submicrometer‐sized crystals were distributed among the grooves of the porcelain plate or among the grains of the sandpaper used in these tests. These observations stress the need for revisiting the current standards used for determining the hazardous properties like friction and impact sensitivity of energetic materials in the case, where the sample consists of submicrometer‐sized crystals. Recommendations were suggested to develop new test methods that only use the interactions between the particles and therefore allow the application of sensitivity tests for submicrometer/nano‐sized energetic materials.
Transition from Impact‐induced Thermal Runaway to Prompt Mechanochemical Explosion in Nanoscaled Ni/Al Reactive Systems
Authors: Reeves Robert V. , Mukasyan Alexander S. , Son Steven F. 
Published: May 2013

AbstractThe effect of microstructure on ignition sensitivity and reaction behavior is investigated for nanoscaled Ni/Al gasless reactive systems. Nanometric homogeneity of the reactive media was achieved through (a) conventional mixing of nanometric powders; (b) short‐term high‐energy ball milling (HEBM) of micrometer‐sized powders. Sensitivity to thermal inputs is investigated by differential thermal analysis and mechanical sensitivity is studied by high‐rate shear impacts. The composite Ni/Al particles prepared by HEBM were extremely thermally sensitive, with reaction initiating at 220 °C, compared to 559 °C for nanometric powder samples and 640 °C for un‐milled, micrometer‐sized Ni+Al powder mixture. In contrast, nanometric powder mixtures were more susceptible to ignition through mechanical means, exhibiting a high‐speed reaction mode that is not observed in HEBM samples. The high‐speed mode preferentially appears in high‐shear regions and is interpreted as a mechanically‐induced thermal explosion. Its progression is tied to the passage of a stress wave in the heterogeneous media that heats and mixes the materials, rather than being propagated due to chemical energy release. The microstructures unique to each material are considered responsible for their individually ignition sensitivities. Specifically, the finely interspersed porosity in nanometric powder mixtures allows direct heating of the reactive interface between Ni and Al particles during compression through pore collapse and plastic deformation, which leads to exceptionally high mechanical sensitivity. The HEBM materials have high specific reactant interface area in the bulk of each composite particle that enhances thermal sensitivity, but the relatively low specific interface area between particles is unfavorable to mechanical ignition.
Effect of spray angle and spray volume on deposition of a medium droplet spray with air support in ivy pot plants
Authors: Foqué Dieter , Pieters Jan G. , Nuyttens David 
Published: May 2013

AbstractBACKGROUNDSpray boom systems, an alternative to the predominantly‐used spray guns, have the potential to considerably improve crop protection management in glasshouses. Based on earlier experiments, the further optimization of the deposits of a medium spray quality extended range flat fan nozzle type using easy adjustable spray boom settings was examined. Using mineral chelate tracers and water sensitive papers, the spray results were monitored at three plant levels, on the upper side and the underside of the leaves, and on some off‐target collectors. In addition, the deposition datasets of all tree experiments were compared.RESULTSThe data showed that the most efficient spray distribution with the medium spray quality flat fan nozzles was found with a 30° forward angled spray combined with air support and an application rate of 1000 L ha–1. This technique resulted in a more uniform deposition in the dense canopy and increased spray deposition on the lower side of the leaves compared with the a standard spray boom application. Applying 1000 L ha–1 in two subsequent runs instead of one did not seem to show any added value.CONCLUSIONSpray deposition can be improved hugely simply by changing some spray boom settings like nozzle type, angling the spray, using air support and adjusting the spray volume to the crop. © 2013 Society of Chemical Industry
Prophylactic Mesh Reinforcement Reduces Stomal Site Incisional Hernia after Ileostomy Closure
Authors: Liu David Shi Hao , Banham Elisabeth , Yellapu Srinivasa 
Published: May 2013

AbstractBackgroundStomal site incisional hernia is a common complication following ileostomy closure. The effectiveness of prophylactic mesh placement at the time of stomal closure is unknown because of fear of mesh infection and subsequent wound complications. The present study investigated whether prophylactic mesh placement reduces the rate of incisional hernia after ileostomy closure without increasing wound complications. The study was based on retrospective review of consecutive ileostomy closures undertaken at a tertiary referral center between January 2007 and December 2011. Hernias were identified through clinical examination and computed tomography.ResultsEighty‐three cases of ileostomy closure were reviewed; 47 patients received mesh reinforcement, and 36 underwent non‐mesh closure (controls). In total, 16 (19.3 %) patients developed incisional hernia, 13 (36.1 %) of which occurred in the control group; 3 (6.4 %), in the mesh group [odds ratio (OR): 8.29; 95 % confidence interval (CI) 2.14–32.08; p = 0.001]. Incisional hernia repair was performed in 3 (23 %) patients in the control group; no hernias in the mesh group required surgery. There was no significant difference in wound infection rates between mesh (2 patients, 4.3 %) and control (1 patient, 2.8 %) groups. No mesh infection was found. Multivariate analysis demonstrated that malignancy (OR: 21.93, 95 % CI 1.58–303.95; p = 0.021) and diabetes (OR: 20.98, 95 % CI 3.23–136.31; p = 0.001) independently predicted incisional herniation, while mesh reinforcement prevented hernia development (OR: 0.06, 95 % CI 0.01–0.36; p = 0.002).ConclusionsMesh placement significantly reduced the incidence of incisional hernia following ileostomy closure, but without increasing complication rates. This technique should be strongly considered in patients at high risk of hernia development.
Clinical Issues‐June 2013
Authors: Burlingame Byron L. 
Published: May 2013

This MonthOR fire extinguisher placementKey words: fire, fire extinguisher.Storage of freestanding oxygen gas cylindersKey words: oxygen storage, medical gas, gas cylinders.Use of extension cords in the ORKey words: electrical cords, extension cords, multiple outlet cords, power strips.Documenting student RN first assistants on the OR recordKey words: RN first assistant, RNFA, documentation, first assistant, preceptor.Education requirements for the advanced practice RN first assistantKey words: advanced practice RN, APRN, education, first assistant, APRN first assistant.