bluuebunny/crossref_metadata_2025 huggingface dataset:
The component acids of the testa and kernel fats of the oil palm
Authors: Carsten H. A. , Hilditch T. P. , Meara M. L.
Published: April 2014

The fat in the thin brown testa of the palm kernel (Elœis guineensis) contains more oleic and linoleic acids, and less lauric acid, than that of the endosperm; linoleic acid amounts to 5% or more, and oleic acid to 20–25%, of the total fatty acids (the corresponding proportions in the endosperm fat being about 1% and 11–12%). The proportion of free fatty acids in the testa fat was about three times that in the enclosed kernels or endosperm, but the proportions of the component acids in the acidic part of the fat did not differ sensibly from those in the neutral testa fat. The higher proportion of free fatty acids is probably due to the testa fat being more accessible to lipolytic enzymes introduced from moulds at the outer surface of the kernels.
Some reactions of thionyl chloride and their application to the determination of sulphur chlorides in technical thionyl chloride
Authors: Harrington Thomas , Boyd Thomas H.
Published: April 2014

A simple method of estimating the amounts of sulphur mono‐ and di‐chlorides in technical thionyl chloride is described. It has been shown that small amounts of sulphur chlorides in thionyl chloride are hydro‐lysed by excess of water to give polythionic acids. Iron catalyses a reaction between thionyl chloride and sulphur, producing sulphur mono‐chloride. The former reaction has been made the basis of a satisfactory analytical method and difficulties caused by the latter reaction have been overcome.
The resolution of r‐tartaric acid by means of d‐N‐methylamphetamine (d‐N‐methyl‐β‐phenylISO‐propylamine)
Authors: Walton E.
Published: April 2014

d‐N‐Methylamphetamine l‐bitartrate, readily obtainable from its r‐bitartrate by crystallisation from water, has been converted directly into barium l‐tartrate, from which l‐tartaric acid has been isolated in the known manner. This process, besides giving satisfactory yields through‐out, offers other advantages over previously described methods.
The corrosion of copper evaporator tubes
Authors: Inglesent H. , Storrow J. Anderson
Published: April 2014

Copper heating tubes from a glucose evaporator have been examined to determine the cause of their corrosion. The progressive degree of attack along the length of the tubes on the liquor side suggested that the moto‐electric effect was the major factor leading to reduction in their wall thickness. Tests on a model evaporator apparently confirm this explanation.
The nutritive value of ready‐to‐eat break‐fast cereals
Authors: Booth R. G. , Moran T. , Pringle W. J. S.
Published: April 2014

Twenty‐five cereal breakfast foods manufactured in this country have been examined in order to assess the effects of the methods of manufacture upon their nutrient content. Pressure cooking of grain causes a considerable loss of vitamin B1 and appreciable hydrolysis of phytic acid; riboflavin and nicotinic acid are unaffected. It is suggested that breakfast cereals should be fortified with vitamin B1 at a late stage in their manufacture to the level existing in the original grain. This would ensure an adequate B1: non‐fat calorie ratio in the usual breakfast cereal portion of the meal.
Preparation of drinking water from sea water
Authors: Ingleson H.
Published: April 2014

An investigation has been made of chemical methods of treating sea water to produce drinking water, for use by air‐crews adrift in rubber dinghies on the open sea. The method finally developed consisted in treating sea water with briquettes of a reagent containing silver zeolite, barium hydroxide octohydrate, silver oxide, fuller's earth, and graphite.
The effect of pH on fungistatic activity of dinitro‐O‐cresol
Authors: Brian P. W.
Published: April 2014

Results are presented showing that the fungistatic activity of dinitro‐o‐cresol (DNOC) solutions, adjusted to various pH values, is closely correlated with the concentration of undissociated DNOC. In fact, the fungistatic efficiency of aqueous DNOC solutions can be accounted for on the assumption that the DNOC anion has 1/40th the toxicity of the undissociated molecule. It is suggested that the observed increases in insecticidal activity of DNOC‐petroleum oil winter washes at low pH can also be accounted for by the increased concentration of undissociated DNOC, rather than by the increased concentration of DNOC in the oil phase. Thee concentration of DNOC in the oil phase is in fact an indirect measure of the concentration of undissociated DNOC.
Simulation of stable water isotopic composition in the atmosphere using an isotopic Atmospheric Water Balance Model
Authors: Zhang Xin‐Ping , Guan Hua‐De , Zhang Xin‐Zhu , Wu Hua‐Wu , Li Guang , Huang Yi‐Min
Published: April 2014

In this article, we present a simplified isotopic Atmospheric Water Balance Model (iAWBM), to simulate spatial distribution and temporal variations of δ18O in atmospheric vapour and in precipitation, and the correlations of δ18O in precipitation with precipitation amount and with temperature. This method overcomes deficiencies of the Global Network of Isotopes in Precipitation (GNIP) due to its limitation in space and time resolution and those of the isotope‐enabled General Circulation Models (iGCMs) due to its complexity. The simulated results reproduce well the latitude effect, continent effect and seasonality of δ18O in global precipitation. The simulation suggests that the precipitation amount effect occurs mainly in the low‐mid latitude oceans and monsoon areas, and the simulated temperature effect occurs mainly in the mid‐high latitude continents. However, the simulation results also indicate some temperature effect in some low‐latitude areas where the precipitation amount effect is strong. The modelled precipitation isotopic composition is compared to 3‐year observations in Changsha, China (2010–2012). The simulations reproduce the observed seasonal variations of δ18O in precipitation. The basic characteristics that stable isotopes in precipitation are depleted during the rainy season and enriched during the dry season, and the observed amount effect is well simulated under daily time scale. The simulated weighted average δ18O (−6.58‰) in precipitation during the prevailing winter monsoon season (October–March) is almost the same as the observed δ18O in the same period (−6.56‰), but the simulated δ18O (−9.58‰) during the prevailing summer monsoon season (April–September) is lower than the observed δ18O (−7.66‰). The simulation result also shows temporal variations of vapour isotopic composition in the atmosphere, and the proportional contributions from horizontal vapour exchange, precipitation and evaporation.
Doing E‐Business in France: Drivers of Online Trust in Business‐to‐Consumer Websites
Authors: Bartikowski Boris , Singh Nitish
Published: April 2014

How can online marketers improve the level of trust among their consumers in order to ensure greater satisfaction with the services offered by their websites? In the absence of a detailed understanding of which website elements drive trust online, many online marketers are missing important opportunities that can make the difference between success and failure in selling and servicing online. Since France is among the largest online markets worldwide, an empirical analysis of the content of 206 websites from 11 business categories that target French consumers offers practical guidance to business‐to‐customer (B2C) marketers who strive to improve the level of online trust. The study's results provide a comprehensive set of 15 perceptual drivers of online trust with operational examples. Integrating these elements in website design may increase site credibility and facilitate transactions. The most salient trust drivers are related to brand reputation, layout design, content quality, expertise, and navigation. Depiction of cultural markers (language, typical colors, symbols, country references) is another key driver of online trust in France. Online retailers, particularly those targeting French markets, may use the study's findings to design more trusted websites or to benchmark their online trust creation capabilities. © 2014 Wiley Periodicals, Inc.
Fearless Feedback Boosts Trust While Replacing Traditional Performance Appraisal at Independent Living, Inc.
Authors: Hauck Wally
Published: April 2014

The leaders of Independent Living, Inc., a consumer‐directed, cross‐disability advocacy and service organization dedicated to enhancing the quality of life for persons with disabilities, recognized the need to enable management and staff to achieve organizational excellence under increasing cost pressures and funding challenges while becoming ever more responsive to the changing and increasingly demanding needs of a growing clientele. Analysis revealed that the organization's performance management system was hampering its effectiveness and that a new process for improving trust and developing capable leaders at every level was needed. Grounded in systems thinking, a fearless feedback approach was implemented to fully engage staff and spur both productivity and innovation. The results after four years show dramatic improvements in the value of workplace conversations, the level of trust, individual and team performance, leadership skills, and the ability of employees and managers to develop work‐related skills, accomplish goals, communicate more effectively with each other, and learn. Overwhelmingly, ILI staff members identified fearless feedback as an improvement over the traditional performance appraisal program previously employed. © 2014 Wiley Periodicals, Inc.
Electronic Health Records: Cure‐All or Chronic Condition?
Authors: Kimble Chris
Published: April 2014

Computer‐based information systems feature in almost every aspect of our lives, and yet most of us receive handwritten prescriptions when we visit our doctors and rely on paper‐based medical records in our health care. Although electronic health record (EHR) systems have long been promoted as a cost‐effective and efficient alternative to this situation, clear‐cut evidence of their success has not been forthcoming. An examination of some of the underlying problems that prevent EHR systems from delivering the benefits that their proponents tout identifies four broad objectives—reducing cost, reducing errors, improving coordination, and improving adherence to standards—and shows that they are not always met. The three possible causes for this failure to deliver involve problems with the codification of knowledge, group and tacit knowledge, and coordination and communication. There is, however, reason to be optimistic that EHR systems can fulfill a healthy part, if not all, of their potential. © 2014 Wiley Periodicals, Inc.
Diversity dynamics of the Late Cenozoic rodent community from south‐western Kansas: the influence of historical processes on community structure
Authors: MARTIN ROBERT A. , PELÁEZ‐CAMPOMANES PABLO
Published: April 2014

This study used the dense late Cenozoic rodent record of south‐western Kansas to test for an equilibrium in species richness through millions of years, identify and clarify historical influences on species richness, determine the relative contribution of immigration, speciation and local extinction to species originations at the community level, and calculate background extinction rates to compare with modern species losses due to anthropogenic activities. The Meade Basin rodent community has been in equilibrium, with an average of about 17 species, for almost 5 million years. No speciation events were identified in the Meade Basin rodent record; although speciation ultimately contributes to the regional species pool, local speciation events contributed little to community structure. Extinctions and immigrations continued through the study period, with elevated bouts of turnover correlated with global cooling events and lowered sea level associated with the Beringian land bridge. Turnover was generated primarily by stochastic climatic agents at several temporal scales, possibly including rapid and devastating regional volcanic ashfalls. None of the extinction rates recorded in the Meade Basin system rivals extinction levels in modern species due to anthropogenic activities.
A 560–440 ka tephra record from the Mercure Basin, southern Italy: volcanological and tephrostratigraphic implications
Authors: GIACCIO BIAGIO , GALLI PAOLO , PERONACE EDOARDO , ARIENZO ILENIA , NOMADE SEBASTIEN , CAVINATO GIAN PAOLO , MANCINI MARCO , MESSINA PAOLO , SOTTILI GIANLUCA
Published: April 2014

Integrated electron microprobe analyses (EMPAs) on glass and Sr–Nd isotope analyses have been performed on 17 tephras from the Middle Pleistocene Mercure lacustrine succession, southern Apennines. Two 40Ar/39Ar ages and the recognition of four relevant tephras from Colli Albani, Sabatini and possibly Roccamonfina volcanoes allowed us to ascribe the investigated succession to the late Marine Isotope Stage (MIS) 15–12 interval (560–440 ka). The Sr–Nd isotopes and major element glass compositions allowed us to attribute 10 out of the other 13 tephras to a poorly known activity of the Roccamofina volcano, whereas two layers were tentatively attributed to previously unknown Middle Pleistocene activity of Ponza Island or Campanian volcanoes, and one to Salina Island. The tephrostratigraphic correlation of the Mercure tephras with the Acerno lacustrine pollen record (Campania) also allowed us to evaluate the climatostratigraphic position of the tephras within the framework of the MIS 15–12 climatic variability. These results were obtained by combining the Sr–Nd isotope ratio with EMPA and 40Ar/39Ar geochronological data. This confirms the notable consistency of this approach for studying the Mediterranean Middle Pleistocene tephrostratigraphy, which, despite its great potential for both volcanology and Quaternary studies, has been hitherto barely explored.
Modelling glacier advances and related climate conditions during the last glaciation cycle in the Kuzigun Valley, Tashkurgan catchment, on the north‐west Tibetan Plateau
Authors: XU XIANGKE , DONG GUOCHENG , PAN BAOLIN
Published: April 2014

Understanding regional climate during the last glaciation cycle (LGC) is far from complete for the north‐western Tibetan Plateau. Recent improvements in understanding glacial extents and chronologies in the Tashkurgan catchment, north‐west Tibetan Plateau, present an opportunity to estimate the glacial climatic conditions of the LGC. Here we use a coupled mass‐balance and ice‐flow model to reconstruct glacier advances in the Kuzigun Valley during the LGC and quantify the related climate conditions in the Tashkurgan, Hangdi, and Kuzigun glacial stages for the region. The model results show that the Kuzigun Valley contained ice volumes of 5.713 ± 0.005, 4.874 ± 0.005 and 3.631 ± 0.004 km3 with equilibrium line altitude‐lowering values of ∼500, ∼560 and ∼610 m in the three successive glacial stages, respectively. By referencing the climatic δ18O proxy records, we conclude that temperature decreased by 5–8, ∼4 and <4 °C with precipitation levels of 30–70, ∼100 and >140% modern values in the Kuzigun, Hangdi and Tashkurgan glacial stages, respectively. Our climatic estimates for the Kuzigun stage are generally consistent with previous studies that showed the Last Glacial Maximum climate was 4–9 °C colder than today on the Tibetan Plateau. More accurate climate proxies are needed for evaluating our modelled Tashkurgan climatic conditions.
Synthesis of N‐Aminopyrrolidine by the Raschig Process: Kinetic and Mechanistic Study of the Monochloramine‐Pyrrolidine Interaction
Authors: Dhenain A. , Darwich C. , Frangieh M. R. , Goutal L. , Delalu H.
Published: April 2014

1‐Pyrrolidinamine (NAPY) belongs to a family of large compounds, namely the alkylhydrazines, used as precursors for different targets in fine chemicals, such as pharmaceuticals and cosmetics. Different synthetic methods are described in the literature; however, many of them are not adaptable on a large scale. The Raschig process appears to be the most relevant method for preparing hydrazines at the industrial scale: hydrazines are obtained by two successive reactions. The first involves the formation of monochloramine from sodium hypochlorite and excess ammonia. The second consists of reacting, in a basic medium, the monochloramine previously synthesized with excess amine to provide the corresponding hydrazine. It is a clean and selective method, distinguished by its nonpolluting aspect, its low cost, and the feasibility of continuous transposition to industrial scale. However, it presents some disadvantages linked to the low hydrazine concentrations in the synthesis solutions. The optimization of the synthesis parameters is therefore essential and requires a detailed kinetic and mechanistic study of the reaction of NAPY formation by the chloramine/pyrrolidine interaction. The kinetics of the NAPY formation reaction were studied in alkaline medium, at first at a temperature of 25°C. Excess pyrrolidine was used with respect to NH2Cl, in order to minimize the influence of side reactions. Owing to the high reaction rates, the essays were carried out in a dilute medium, using reagent concentrations ranging between 1 × 10−3 and 4 × 10−2 M. The ionic strength of the medium was established by NaOH concentration (0.1 M). Then, the influence of the temperature was studied between 15 and 45°C for NH2Cl and PY concentrations, respectively, equal to 2 × 10−3 and 0.01 M, in order to check the conformance to the Arrhenius law. Finally, the characterization of the reaction mixture permitted establishment of a global reaction scheme, including two main secondary reactions.
Diagnosis and management of biliary complications in pediatric living donor liver transplant recipients
Authors: Feier Flávia H. , Chapchap Paulo , Pugliese Renata , da Fonseca Eduardo A. , Carnevale Francisco C. , Moreira Airton M. , Zurstrassen Charles , Santos Aline C. , Miura Irene K. , Baggio Vera , Porta Adriana , Guimarães Teresa , Cândido Helry , Benavides Marcel , Godoy Andre , Leite Katia M. R. , Porta Gilda , Kondo Mario , Seda-Neto João
Published: April 2014

The incidence of biliary complications (BCs) after living donor liver transplantation (LDLT) can reach 40%. Published data on the pediatric population are limited, and treatment protocols vary. Our aim was to describe the clinical scenario for BCs and treatment approaches after LDLT. Between October 1995 and December 2012, 489 pediatric LDLT procedures were performed. BCs developed in 71 patients (14.5%). Biliary strictures (BSs) developed in 45 (9.2%) patients, and bile leaks (BLs) developed in 33 patients (6.7%). The BL diagnosis was clinical in all cases, and 69.7% of the patients underwent surgery. Nearly half of the BS cases had clinical features or suggestive ultrasound findings. Liver biopsy findings suggested BSs in 51.7%. Percutaneous transhepatic cholangiography was performed in 95.6% of the BS patients. The success rate was 77% [mean number of percutaneous biliary interventions (PBIs) = 3.9 ± 1.98, median drainage time = 8 months]. In conclusion, BL patients can be managed with conservative therapy, even though most of these patients will ultimately be treated with surgery. Diagnosing a BS requires a high degree of clinical suspicion because the available resources for its identification can fail in up to 50% of cases. A higher number of PBIs and the use of a drainage catheter for a longer time may be required to achieve better results with this technique. Liver Transpl 20:882–892, 2014. © 2014 AASLD.
Regulating Schwann Cells Growth by Chitosan Micropatterning for Peripheral Nerve Regeneration In Vitro
Authors: Li Guicai , Zhao Xueying , Zhang Luzhong , Wang Caiping , Shi Yunwei , Yang Yumin
Published: April 2014

To address the effect of chitosan micropatterning on nerve regeneration, two sizes of parallel microstripes of chitosan are fabricated on the surface of coverslips using a micromodeling method. The morphology of the prepared polydimethylsiloxane stamps and chitosan micropatterning is observed by scanning electron microscopy and the wettability of the prepared micropatterning is evaluated using water contact‐angle measurements. Schwann cell (SC) culture is used to evaluate the effect of chitosan micropatterning on cell behavior. The results show that the stripe‐like chitosan micropatterning can be successfully fabricated on coverslip surfaces. SCs on 30/30 μm chitosan micropatterning shows the most obvious cell orientation. Moreover, the secretion of nerve growth factor by SCs indicate that the chitosan micropatterning has no negative influence on the normal physiological function of the cells. Thus, the study suggests that chitosan micropatterning can induce and regulate the growth of SCs well, which may have potential application in peripheral nerve regeneration.
Anisotropic Supports in Metallocene‐Catalyzed Polymerizations: Templates to Obtain Polyolefin Fibers
Authors: Joe Daejune , Golling Florian E. , Friedemann Kathrin , Crespy Daniel , Klapper Markus , Müllen Klaus
Published: April 2014

The formation of polyethylene fibers via metallocene‐catalyzed polymerization using anisotropic organic supports as templates is presented. The supports are obtained by electrospinning a mixture of polyvinyl alcohol and functionalized polystyrene nanoparticles. After loading the MAO‐activated metallocene on the support and olefin polymerization, the obtained catalyst system yields polyethylene fibers displaying a core‐sheath structure with a controlled diameter in the range of 0.3–2 μm. This strategy represents a direct method to fabricate well‐defined polyolefin fibers and mats during the polymerization without any further processing.
Hopf bifurcation in the full repressilator equations
Authors: Buzzi Claudio A. , Llibre Jaume
Published: April 2014

In this paper, we prove that the full repressilator equations in dimension six undergo a supercritical Hopf bifurcation. Copyright © 2014 John Wiley & Sons, Ltd.
Circular‐ring patch antenna with higher order mode for on‐body communications
Authors: Tak Jinpil , Choi Jaehoon
Published: April 2014

A higher order mode (TM31) circular‐ring patch on‐body antenna with shorting pins for on‐body communications in wireless body area network is proposed. Using shorting pins, TM31 resonance mode was generated, while achieving compact low‐profile structure with monopole‐like radiation characteristics. To obtain wide bandwidth, an annular ring with shorting pins having TM31 mode is closely located around the circular patch. The antenna has the overall dimensions of 0.49 λ0 × 0.53 λ0 × 0.025 λ0 at 2.45 GHz in the industrial, scientific, and medical 2.45 GHz band (2.4–2.485 GHz) and the 10‐dB return loss bandwidth is 7.3% ranging from 2.35 to 2.53 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1543–1547, 2014
Broadband circularly polarized printed monopole antenna with unidirectional radiation patterns
Authors: Sze Jia‐Yi , Zhou Zhi‐Hong , Hsu Chung‐I G. , Lin Cheng‐Hong
Published: April 2014

This article proposes a new broadband circularly polarized (CP) printed monopole antenna (PMA) with unidirectional radiation patterns. The simple structure consists of only a circular patch, a tuning rectangular patch, and an inverted‐L strip protruded from the signal line of a feeding asymmetric coplanar waveguide (CPW). Through simple design procedures, a CP PMA with bidirectional radiation patterns and with a fractional CP bandwidth (CPBW) of larger than 35% can be obtained. By placing an open metal cavity underneath the bidirectional PMA without changing the PMA's structural dimensions, one can obtain unidirectional radiation patterns without downgrading the CPBW. In addition, the peak antenna gain can be raised by about 6 dB. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1535–1540, 2014
Electrically small ferrite antenna gain with dc magnetic field for mobile device application
Authors: Lee Jaejin , Hong Yang‐Ki , Lee Woncheol , Park Jihoon , Tanaka Terumitsu , Yun Changhan
Published: April 2014

We demonstrate that electrically small ferrite antenna gain is significantly increased with a small dc magnetic field of compact Nd‐Fe‐B permanent magnet (9.5 × 4.6 × 1.5 mm3). The experimental magnetic tangent loss of the Ni‐Mn‐Co ferrite decreased by about 62%, which was from 0.509 with 0 Gauss to 0.192 with 750 Gauss. The antenna gain increased by 54% (from −10.58 to −4.81 dBi) when the magnetic field of 1600 Gauss was applied to the antenna. The ferrite antenna has the volume of 0.346 cm3 and shows omnidirectional patterns, which are suitable for hand‐held mobile device applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1531–1534, 2014
Design of a meander dipole antenna with dielectric loading for a sensor node of a wireless sensor network
Authors: Lee Jung‐Nam , Park Ju‐Derk , Lee Kwang‐Chun , Park Jong‐Kweon
Published: April 2014

A meander dipole antenna for a sensor node of a wireless sensor network is proposed. The proposed antenna consists of a dipole element, the matching steps, and a circuit using lumped elements. We compared two antennas with and without a matching circuit. The antenna has a simple structure, high gain, and omnidirectional radiation patterns. Details of the proposed antenna design and experimental results are presented and discussed. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1526–1531, 2014
Compact UWB BPF with notched band based on stub‐loaded ring resonator
Authors: Deng Kun , Chen Jian‐Zhong , Zhang Jun‐Zhan , Wu Bian , Shi Xiao‐Wei
Published: April 2014

A compact planar microstrip ultrawideband bandpass filter is presented, which uses a stub‐loaded ring resonator. A quarter‐wavelength open stub is used to realize a notched band. Center frequency and bandwidth of the notched band can be easily changed by tuning the stub length and line width, respectively. The measured insertion loss is less than 1.1 dB, the return loss is more than 15 dB in most of two passbands. The bandwidth of the narrow notch band is about 0.4 GHz and the attenuation is more than 22.3 dB at the center frequency of the notch. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1520–1522, 2014
High‐performance narrowband superconducting filters with high Q resonators at X‐band
Authors: Song Xiaoke , Wei Bin , Cao Bisong , Zhang Xiaoping , Guo Xubo , Zhang Guoyong , Xu Zhan
Published: April 2014

This paper presents two narrowband high‐temperature superconducting (HTS) filters at 10 GHz with a 0.6% fractional bandwidth. Uniform impedance rectangular resonator (UIRR) and stepped impedance H‐type resonator (SIHR) are proposed to achieve HTS filters with high Q value, low sensitivity, weak coupling, and good parasitic response. A six‐pole HTS filter that has UIRRs with a Q value of 17,700 is fabricated; this filter has a 19.9 dB return loss and a 0.38 dB insertion loss. An eight‐pole HTS filter that has SIHRs with a Q value of 12,100 is also manufactured; this filter has a 12.2 dB return loss and a 0.64 dB insertion loss. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1516–1520, 2014
Novel compact microstrip dual‐mode multistub‐loaded stepped‐impedance resonator and application to communication systems
Authors: Babakan Amir , Karimi Gholamreza
Published: April 2014

In this article, a novel compact microstrip dual‐mode multistub‐loaded stepped‐impedance resonator is introduced. Stepped‐impedance resonator can be used for achieving the fundamental resonance frequency; however, the size of this structure is not compact and resonance frequencies are dependent. Utilizing multistubs as loaded elements improves size miniaturization with low permittivity substrate and brings the advantage of flexible controlling of one resonance frequency whereas the other one is fixed. As an application, a dual‐band bandpass filter is presented to operate at 3.5 and 5.2 GHz, corresponding to the worldwide interoperability for microwave access and wireless local area network applications. An overall good agreement between the measured and simulated results is observed, confirming the proposed method. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1567–1570, 2014
Design of a resistively loaded modulated scatterer for ground penetrating radar measurements
Authors: Sustman James W. , Scott Waymond R.
Published: April 2014

A broadband resistively loaded modulated scatterer (RLMS) is developed for ground penetrating radar experiments and optimized to reflect signals that are high in strength and have a flat frequency response with a linear phase variation. The linear phase makes the scattering compact in time and easily interpreted in the time‐domain. A novel method of measuring the modulation with a standard network analyzer is presented, and two example measurements are presented. The RLMS is used to measure the two‐way pattern of a pair of Resistive‐Vee dipole antennas, and to measure the response of a scatterer in soil with a moving water table. The RLMS performs well in these experiments. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1557–1561, 2014
Consciousness and subconsciousness detection model under Čerenkov radiation
Authors: Yupapin P. P. , Thammawongsa N. , Ali J.
Published: April 2014

A new model of space‐time paradox concept is proposed to describe the  states, where the connection between whispering gallery mode probe and brain signal form and the mind‐mater interfacing information can be described. The uncertainty of the paradox pair is described by using the well known Heisenberg's uncertainty principle. This proposal is useful for possible mind and dream investigations. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1584–1587, 2014
Low‐cost wideband double‐layer microstrip coupled‐line directional coupler with high directivity
Authors: Esfeh Babak Kazemi , Raskin Jean‐Pierre , Van Moer Wendy
Published: April 2014

In this article, a low‐cost double‐layer microstrip structure with a gap space between the two substrate layers is used to develop a microstrip coupled‐line directional coupler with high directivity. The proposed design shows a high directivity (more than 20 dB) over a wide frequency bandwidth (more than 2 GHz). The double‐layer directional coupler, designed on FR4 substrate material at 2.4 GHz provides more than 30 dB isolation. The simulation and measurement results are in good agreement. By applying a simple and low‐cost fabrication process and design, the directivity of the directional coupler is enhanced by more than 10 dB compared with a microstrip structure. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1570–1575, 2014
Nested metamaterials antenna for RFID traceability
Authors: Naoui Seif , Latrach Lassaad , Gharsallah Ali
Published: April 2014

In this article, we propose a new approach to study a suitable structure of metamaterial antennas for radio frequency identification (RFID) technology that operates in the UHF band. This antenna is constituted by a dipole associated to resonant materials. These materials are the split ring resonators forming the nested metamaterial by a network fee specific and homogeneous structure that can produce an effective negative permeability. Thanks to the effect metamaterials, we can improve the performance and reduce the size of the studied antenna, which is very important for the RFID applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1622–1626, 2014
Design of an X/KU band OMT based on a Bøifot junction using capacitive posts
Authors: Park Kwang Woo , Choi Hak Keun
Published: April 2014

In this article, an orthomode transducer (OMT) using a Bøifot junction with capacitive posts for the X/Ku band is proposed. The structure of the proposed OMT is based on the Bøifot junction with capacitive posts, to obtain wideband characteristics, and to improve return loss. The proposed OMT consists of three parts: four‐port junction, vertical port, and horizontal port. The proposed OMT is fabricated, and then measured, to show return loss over 20 dB, insertion loss less than 0.99 dB, and isolation over 50 dB, for vertical and horizontal polarization of the X/Ku band. It is proved that the computed results agree well with the measured ones. Therefore, it is confirmed that the proposed OMT can be used for satellite communication systems. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1617–1622, 2014
Very compact palmate leaf‐shaped CPW‐FED monopole antenna for UWB applications
Authors: Fakharian Mohammad M. , Rezaei Pejman
Published: April 2014

This article presents a very compact coplanar waveguide‐fed planar monopole antenna for ultrawideband (UWB) applications. The antenna consists of a palmate leaf‐shaped radiator with a modified shaped ground plane on the same side of the substrate. The measured impedance bandwidth of the proposed antenna is from 3.08 to over 14 GHz with a ratio of about 4.6:1 for VSWR ≤ 2. Experimental results show that the proposed antenna has stably omnidirectional H‐plane radiation patterns with low cross‐polarization level and average peak gain of 3 dBi across the UWB. The antenna dimensions are restricted to 13.5 × 14.8 × 0.8 mm3. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1612–1616, 2014
Infrared imaging in the analysis of planar antennas
Authors: Díaz de León Torres H. , Kolosovas‐Machuca S. , Simón Jorge , Vera‐Reveles Gustavo , Briones Edgar , González Francisco J.
Published: April 2014

In this study, a noninvasive method based on infrared thermography is presented to obtain the resonant frequency of a dipole antenna in the microwave region. The study was performed by visualizing the temperature increase due to the Joule heating of the antenna fed by a voltage source. Results show a significant increase in dissipated heat at 830MHz where the resonance is expected. This method can be used to measure planar antennas noninvasive and in‐situ without having to take them to a specialized antenna‐measurement facility. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1610–1612, 2014
Signal upconversion for a radio‐over‐fiber system with modulation types based on a frequency quadrupling technique
Authors: Lin Jhe‐Min , Ho Wen‐Jeng , Chang Yu‐Peng , Peng Peng‐Chun , Lu Hai‐Han
Published: April 2014

In this study, optical upconverted microwave frequency generation was experimentally demonstrated using a frequency quadrupling technique based on two types of baseband signal modulation in a radio‐over‐fiber (RoF) system. The measured results revealed that an error‐free transmission could be achieved without causing the periodic power fading affect, and that clear eye diagrams were obtained after a 20‐km transmission by using baseband/RF mixed‐signal external modulation. The proposed method is a feasible technique for generating a 622 Mbps (1.25 Gbps)/15 GHz frequency quadrupling RoF signal without using narrow‐band optical notch filters or sophisticated optical modulators. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1603–1610, 2014
A low profile dual‐band dual‐polarized patch antenna array with integrated feeding network for pico‐base station applications
Authors: Li Jinxin , Yang Shiwen , Li Bing , Nie Zaiping
Published: April 2014

A low profile dual‐band dual‐polarized patch antenna array for pico‐base station is presented in this article. The proposed antenna array uses a stacked configuration composed of three layers of substrates, with circular patches etched on the upper side of the upper substrate and quasi‐cross‐shaped slotted circular patches etched on the upper side of the middle substrate. A novel feeding network composed of two hybrid couplers and four power dividers is printed on the bottom side of the lower substrate. Simulated and measured results show that the proposed antenna array achieves a return loss lower than −14 dB over the dual‐frequency band of 1.92–1.98 and 2.11–2.17 GHz. Moreover, stable radiation patterns with a peak gain of 10.7–11.7 dBi is obtained within the operating band. The proposed antenna array is easy to realize shaped beam and can be used for pico‐base station antennas. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1594–1600, 2014
Design of low‐power CMOS VCO based on current‐reused topology with center‐tapped inductor bias
Authors: Hsu Meng‐Ting , Chung Cheng‐Chuan , Ou An‐Cheng
Published: April 2014

This article presents a completely integrated 1.1 V 5.15 GHz CMOS voltage‐controlled oscillator (VCO) with self‐body‐biased technique to save the power consumption. MOS varactors are used to maintain a wide tuning range. The VCO was measured with a 1.1 V supply voltage and the tuning range of 16% from 5.15 to 6.05 GHz. The measurement of phase noise is −114.63 dBc/Hz at 1 MHz offset from the carrier frequency of 5.15 GHz. The VCO core power dissipation is 0.8 mW. The figure‐of‐merit is −189.8 dBc/Hz. The VCO circuit was implemented by TSMC 0.18 μm CMOS process. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1587–1590, 2014
Low‐profile multibranch monopole antenna with integrated matching circuit for Lte/Wwan/Wlan operation in the tablet computer
Authors: Lin Po‐Wei , Wong Kin‐Lu
Published: April 2014

A low profile, small‐size, planar tablet computer antenna for the long‐term evolution (LTE)/wireless wide area network and 2.4‐GHz WLAN operation is presented. The antenna is formed by three monopole strips configured into a compact configuration and printed on a thin FR4 substrate of size 10 × 40 mm2. A high‐pass matching circuit is integrated thereon, without increasing the antenna size, to greatly enhance the antenna's low‐band bandwidth to cover the LTE700/GSM850/900 operation (704–960 MHz) with a low‐antenna profile of 10 mm. The antenna's higher band is formed by two wide resonant modes contributed by the monopole strips and can cover the GSM1800/1900/UMTS/LTE2300/2500 operation (1710–2170/2300–2400/2500–2690 MHz). In addition, one of the resonant modes in the higher band can be adjusted to occur at about 2.4 GHz such that enhanced radiation characteristics for frequencies in the 2400–2484‐MHz WLAN band are obtained for the proposed antenna. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1662–1666, 2014
Compact dual‐band slot antenna with capacitor loading
Authors: Jin Zhe‐Jun , Yun Tae‐Yeoul
Published: April 2014

A compact dual‐band slot antenna with capacitor loading is proposed for the wireless local area network bands (2.4–2.49 and 5.15–5.35 GHz). The antenna is composed of a modified L‐shaped slot and a capacitor. The capacitor is used to generate two surface‐current paths on the ground and to miniaturize the antenna size. The proposed antenna has an omni‐directional radiation pattern with antenna peak gains of 2.2 dBi at 2.44 GHz and 2.7 dBi at 5.25 GHz. Radiation efficiencies are greater than 60% over the operating frequency bands. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1653–1658, 2014
Compact microstrip dual‐band bandpass filter using short‐circuited stub‐loaded open loop resonators
Authors: Ma Xing‐Bing , Zhang Feng‐Shan
Published: April 2014

In this article, a compact dual‐band microstrip bandpass filter is proposed using two short‐circuited stub‐loaded open loop resonators and two common open loop resonators. The short‐circuited stub‐loaded resonators can generate two resonant modes. Under odd mode, the short‐circuited stub at the central does not affect the resonant frequencies, and four resonators tightly coupling with each other work at the same frequencies, a wideband passband is obtained. Whereas under the even mode, considering the influences from short‐circuited stubs, the resonant frequencies are decided only by two short‐circuited stub‐loaded resonators, two common resonators are seen as parts of feedlines connected to 50 Ω. A new transmission zero is created between two passbands to improve the selectivity. Good agreement is achieved between simulation and measurement. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1651–1653, 2014
Higher order mode generation in millimeter wave regime by directly launched fundamental mode
Authors: Choe Mun Seok , Choi EunMi
Published: April 2014

We report on a novel method to generate higher order modes in the frequency range of millimeter and submillimeter wave regime. The method uses magnetic coupling scheme between waveguide fundamental mode and a cavity mode. A TE62 mode at W‐band was considered for design using the proposed scheme. The suggested method simplifies a mode generator design allowing direct feeding via a standard fundamental waveguide and also provides a compact mode generator to design extremely higher order mode in a cavity. In addition, it opens a new and novel way to develop high power high gain gyrotron amplifiers at millimeter and submillimeter wave regime. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1648–1651, 2014
Uwb multiresonance antenna with rejection of intelligent transport system band using a cross‐shaped conductor‐backed plane
Authors: Ojaroudi Nasser , Ghadimi Noradin
Published: April 2014

This article presents an ultrawideband (UWB) microstrip monopole antenna with band‐notched function around 5.79–6.40 GHz to avoid any interference from the intelligent transport system (ITS). The proposed antenna consists of an ordinary square radiating patch, a feed‐line and a modified ground plane with pair of rotated H‐shaped slots and cross‐shaped conductor‐backed plane. By cutting a pair of rotated H‐shaped slots, additional resonances at higher frequencies are excited and hence much wider impedance bandwidth can be produced, which provides a wide usable fractional bandwidth of more than 135%. In the proposed design, to generate the ITS band‐stop performance, a cross‐shaped conductor‐backed plane is embedded in the ground plane. The proposed antenna can operate from 3.02 to 16.5 GHz with VSWR < 2 and with a rejection band around 5.79–6.40 GHz. The antenna has an ordinary square radiating patch, therefore, displays a good omnidirectional radiation pattern even at higher frequencies. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications. The proposed monopole antenna configuration is simple, easy to fabricate and has a small size of 12 × 18 × 1.6 m3. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1641–1644, 2014
A high‐performance low‐noise amplifier for 71–76, 76–77, and 77–81 GHz communication systems in 90‐NM CMOS
Authors: Lin Yo‐Sheng , Wang Chien‐Chin , Lee Guan‐Lin , Chen Chih‐Chung
Published: April 2014

A low power and wideband three‐stage millimeter‐wave low‐noise amplifier (LNA) for 71–76 GHz high‐speed point‐to‐point wireless link, and 76–77 GHz long‐range and 77–81 GHz short‐range automotive radars using standard 90‐nm CMOS technology is reported. T‐match technique is utilized to achieve simultaneously wideband input and output impedance matching, wideband power gain (S21) and wideband noise figure (NF) at W‐band. The LNA consumes 21.1 mW, achieving S11 better than −10 dB for frequencies 62.3–82.4 GHz, S22 better than −10 dB for frequencies 62.8–84.6 GHz, S12 better than −29 dB for frequencies 72–84 GHz, and group delay variation smaller than ±6.5 ps for frequencies 70–90 GHz. Additionally, high and flat S21 of 13.1 ± 1.5 dB is achieved for frequencies 72–84 GHz, which means the corresponding 3‐dB bandwidth is 12 GHz. Furthermore, the LNA achieves minimum NF of 6.2 dB at 78 GHz and NF of 6.8 ± 0.6 dB for frequencies 75–82 GHz, one of the best NF results ever reported for a W‐band CMOS LNA. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1673–1680, 2014
Nonadiabatic microfiber based mode‐locked erbium‐doped fiber laser using graphene
Authors: Sulaiman Azlan , Wadi Harun Sulaiman , Ahmad F. , Ahmad Harith
Published: April 2014

A new compact and low threshold mode‐locked Erbium‐doped fiber laser (EDFL) using nonadiabatic microfiber in conjunction with a graphene saturable absorber is demonstrated. The graphene was synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulfate aqueous solution. Graphene flakes obtained from the process are mixed with polyethylene oxide as the host polymer to produce composite solution which acts as passive mode locker in the EDFL linear cavity. Mode‐locked laser, with a threshold of less than 10 mW, pulse repetition rate of 55.8 MHz, and pulse duration of 0.82 ps, is achieved. The EDFL operates at around 1531.8 nm with an average output from 0.1 mW, pulse energy of 2 pJ at the 980 nm pump power of 10 mW. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1670–1673, 2014
A wavelength spacing switchable and TUNABLE high‐birefringence fiber loop mirror filter
Authors: Bian Si‐Yuan , Ren Mei‐Qi , Wei Li
Published: April 2014

We demonstrated an all‐fiber birefringent comb filter with tunable and switchable wavelength spacing. The comb filter is based on a fiber loop mirror (FLM) with three sections of high‐birefringence (HB) fibers and polarization controllers (PCs). The transmission characteristics of the birefringent FLM are dependent of the relative phase difference of the two orthogonal polarization modes and the rotational angles of the different HB fibers. By adjusting the PCs, four different wavelength spacings can be obtained; particularly, interleaving operation—halved and quartered wavelength spacing—can be effectively realized. By using a Jones matrix method, the transmission of the birefringent comb filter is analyzed. The theoretical analysis agrees with the experimental results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1666–1670, 2014
Broadband dielectric loaded parallel coupled microstrip quadrature coupler
Authors: Ashraf Muhammad A. , Sebak Abdel Razik , Alhekail Zeyad O. , Alkanhal Majeed , Alshebeili Saleh
Published: April 2014

In this article, a wideband dielectric loaded coupled line microstrip 90° hybrid coupler is proposed. The effect of changing the effective dielectric constant of substrate by dielectric loading is capitalized to tune the even‐ and odd‐mode velocities of coupled line to achieve wideband performance. Two different designs are perturbed by dielectric loading to achieve minimum amplitude and phase imbalance with good isolation. The simulated and measured results exhibit a coupling of 3 ± 0.7 dB across the band 3.5–10 GHz. The return loss and isolation are found to be better than 15 dB with 3° phase imbalance over the ultrawideband band. The designed coupler has compact size with a dimension of 30 × 20 mm2. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1694–1697, 2014
UWB UHF RFID TAG antenna with branch‐line slots for metallic objects
Authors: Tang Tao , Chen Xiaorong
Published: April 2014

A novel UWB ultrahigh frequency (UHF) radio frequency identification (RFID) tag antenna designed for metallic objects is proposed, which is fabricated on a flexible polyethylene terephthalate substrate for low‐cost production, whose relative permittivity is 3.8 and dielectric loss tangent is 0.02. The overall size of the proposed tag antenna is 56 × 10 × 0.8 mm3. It consists of two coplanar patches which are electrically connected to the metallic ground through two symmetrical shorting walls placed at both edge sides of the patches. The resonant frequency can be adjusted by changing the shorting wall length. Double‐symmetrical branch‐line slots are created to improve the antenna bandwidth. The simulated bandwidth is about 223.5 MHz, which covers the global UHF RFID frequency range. The experimental results show that the maximum read range of the proposed antenna is larger than 2.6 m when it is mounted on a test metal plate with a size of 150 × 150 × 8 mm3. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1689–1691, 2014
Linear response and enhanced sensitivity of Mach–Zehnder interferometer with optimized sensing length
Authors: Yang Tianfu , Wang Tianjiao , Zheng Chuantao , Wang Xibin , Zhang Daming
Published: April 2014

Through a sensing length of 1,1515 µm, the integrated Mach–Zehnder interferometer sensor obtains a quadrature point and linear response in refractive index range of 1.31–1.42. The sensitivity is measured as 225.4 dB/RIU, and the response time is less than 20 s to solutions. Cost‐efficient polymers are used as waveguide materials, and a microfluidic system is achieved. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1697–1701, 2014