bluuebunny/crossref_metadata_2025_split huggingface dataset:
The concept of a fully electronic beamforming antenna array for modern radar systems
Authors: Malafaia Daniel , Varum Tiago , Matos Diogo , Matos João N. , Vieira José 
Published: May 2018

AbstractIn this article the concept of a fully electronic beamforming antenna array for radar systems based on a SDR architecture is proposed and experimentally evaluated in an anechoic chamber. The system uses 2 software defined radio (SDR) transceivers with 4 independently controlled transmitters, allowing an individual digital control of both amplitude and phase of the signal fed to each element of an antenna array. It is also proposed a beamforming method that greatly reduces the sidelobes of the radiation pattern and it was compared to traditional beam steered radiation patterns. Moreover, the proposed architecture has the advantage of being modular, and therefore easily scalable, for larger and more powerful solutions based on the presented antenna array system.
Compact multiband antenna for mobile terminal applications
Authors: Deng Jing Ya , Yao Jiao , Guo Li Xin 
Published: May 2018

AbstractA compact multiband antenna covering LTE700, GSM850/900, DCS1800/PCS1900, UMTS, and LTE 2300/2500 for mobile terminals is proposed. The antenna is comprised a bended feeding strip, 2 parasitic shorted strips and a matching network. The antenna design uses the coupled feed and matching circuit to achieve multiband and wideband performance. The measured impedance bandwidths (S11 < −6 dB) are 360 MHz at the lower band (0.69–1.05 GHz, 41.4% FBW) and 1.29 GHz at the higher band (1.71–3 GHz, 54.8% FBW). Within the frequency band of interest, good radiation performances are obtained. The proposed antenna is applicative for mobile terminals including mobile phones, data cards and wearable devices.
Balloon‐shaped CPW fed printed UWB antenna with dual frequency notch to eliminate WiMAX and WLAN interferences
Authors: Kundu Surajit 
Published: May 2018

AbstractA co‐planar waveguide fed printed ultra‐wideband antenna with dual frequency notch band is proposed in this letter. Small antenna size of 27.5 × 16.5 × 0.8 mm3 is achieved by considering the intersection of three conventional circular disks of equal diameter. Two frequency notch bands of 2.2–3.9 and 5.1–6 GHz are achieved by introducing a curved U‐shaped slot at balloon‐shaped radiator and an inverted patch‐shaped parasitic resonator at the back side of feed respectively. These notch bands prevent the possible interference from coexisting ISM, WiMAX, WLAN, HIPERLAN/2, IEEE 802.11y, and DSRC bands. An inverted U shape slot is added on radiating patch to improve antenna impedance band, gain and efficiency profile. The proposed antenna provides wide bandwidth from 1.75 to 10.3 GHz, with a gain variation between 2 and 4.5 dBi, average radiation efficiency of >80%, linear transfer function and non‐varying group delay in the pass band of operation.
A novel dual band‐notch ultra‐wideband monopole antenna using parasitic stubs and slot
Authors: Guichi F. , Challal M. , Denidni T. A. 
Published: May 2018

AbstractThis paper presents a novel ultra‐wideband (UWB) monopole antenna with dual band‐notch characteristics. The proposed antenna consists of a V‐shaped patch with a stair case defect fed by a 50 Ω transmission line and a semicircular defected ground plane. It is designed for rejection of dual frequency bands, that is, WiMAX (3.17–3.85 GHz) and ITU (7.9–9.1 GHz). The 2 bands are achieved by using 2 parasitic stubs that are inserted on the patch, and an inverted U‐shaped slot that is etched on the transmission line, respectively. The antenna has a nearly omnidirectional radiation pattern with an acceptable gain across the operating frequency band. A good agreement between the simulated and measured results indicates that the proposed UWB antenna design with overall size of 23 × 32 mm2 is suitable for WiMAX/ITU dual band‐notch applications.
Comparison of two matching techniques for UHF RFID tags
Authors: Gourari F. Z. , Meriah S. M. , Protat S. , Dubouil J. , Laheurte J.‐M. 
Published: May 2018

AbstractThis Letter reports a comparison between shunt‐series inductance (SSI) and inductively coupled loop (ICL) matching circuits for ultra high frequency (UHF) Radio Frequency IDentification (RFID) tags. It is shown analytically that an optimized ICL circuit is fully equivalent to an optimized SSI circuit provided that some adjustments are made on the dipole antenna geometry. Numerical and experimental characterizations of the RFID tags built with both topologies confirm this equivalence.
Compact size of the hybrid branch‐line coupler using π‐type transmission‐line
Authors: Lee Tae‐Hyeon , Yoon Ki‐Cheol 
Published: May 2018

AbstractIn this article, the new of the transmission‐line (TL) using π‐type parameter is suggested and it applied to the design of a hybrid branch‐line coupler (HBC). The new HBC is small size than conventional HBC and the designed HBC is used by entire distributed elements. Then, the sizes of the new and conventional HBCs are 9.86 × 11.1 mm2 and 28.2 × 28.6 mm2, respectively. The advantage of the proposed HBC structure has very simple structure and low cost. The proposed HBC using π‐type TL can be applied to mobile communication system.
Microwave measurement system to detect salt and sugar concentration
Authors: Rahman Md. Naimur , Islam Mohammad T. , Sobuz Md. Samsuzzaman 
Published: May 2018

AbstractThis paper deals with the microwave measurement system to measure salt and sugar concentration in water using microstrip technology based on dielectric properties of the solution. The measurement system includes a microstrip patch antenna which is made of a S‐shaped resonator‐based ring patch. The antenna is printed on Rogers RT/duroid 5880 substrate with a thickness of 1.57 mm. The substrate has a relative permittivity of 2.2 and a dielectric constant of 0.0009. The antenna has a compact physical size of 24 × 18 mm. Being used as a sensor the microstrip antenna measure the salt and sugar concentration in terms of the reflection coefficient based on the dielectric properties of the solution. The percentage of salt and sugar in water changes the dielectric constant which also change the reflection coefficients. In the practical experiments, the reflection coefficient decreases with the increment of the percentage of salt and sugar in water.
A compact tri‐band bandpass filter utilizing double mode resonator with 6 transmission zeros
Authors: Rahman Muhib Ur , Ko Dong‐Sik , Park Jung‐Dong 
Published: May 2018

AbstractA new compact tri‐band bandpass filter (BPF) is presented by utilizing 2 double mode resonators incorporating 6 transmission zeros. The proposed BPF is designed to support GSM‐900 (0.83–0.99 GHz), GPS (1.575 GHz), and GSM‐1800 (1.88 GHz) bands. The proposed BPF has been configured to operate in corresponding even and odd modes. The generated odd mode frequency band is fixed while the even‐mode frequency can be set to the desired value by tuning the stub length which makes it easy to design the multiple BPF. Two transmission zeros are introduced on each side of the passband, and overall 6 transmission zeros have been constructed which make the passband highly selective. The designed BPF has been implemented on Rogers‐R03006 and verified with measurement.
66 GHz bias‐dependent equivalent circuit model for CMOS transistor based on 90 nanometers CMOS technology
Authors: Wu Yunqiu , Cong Shili , Zhao Chenxi , Liu Huihua , Kang Kai 
Published: May 2018

AbstractA 66 GHz bias‐dependent transistor model is established in this paper. A small signal equivalent circuit model, which contains transistor intrinsic effects, parasitic effects, and substrate coupling, is presented. Based on this, the nonlinear drain‐source current model and gate capacitance equations are established to represent their bias‐dependent characteristics. To validate the model, a transistor with gate width of 650 × 8 nm and gate length of 0.1 μm is fabricated in 90‐nm CMOS technology. Then, both the DC and small signal performances of the proposed model are investigated under different bias conditions. Good agreements between calculation and measurement results are achieved, which indicates that this model is accurate and reliable for millimeter wave application.
Microstrip triplexer using a common triple‐mode resonator
Authors: El‐Tokhy Amira , Wu Ruiheng , Wang Yi 
Published: May 2018

AbstractAn all‐resonator based triplexer is presented using a double‐stub‐loaded resonator (DSLR) that acts as a common resonator at the junction of the three channels. The open stub DSLR has been analyzed using even and odd‐mode method to reveal the relationship between the three resonant modes. The design offers flexibility of frequency selection. The DSLR resonator is coupled with three sets of hairpin resonators to form the triplexer at 1.8, 2.1, and 2.6 GHz for mobile communication applications. The measurement results are in very good agreement with the simulations.
A novel 2–18 GHz double‐ridged horn antenna with simple structure
Authors: Yue Zhenzhen , Liu Ying , Gong Shuxi 
Published: May 2018

AbstractA 2–18 GHz double‐ridged horn antenna (DRHA) with simple structure is proposed in this paper. Previous studies have found that the radiation patterns of traditional DRHA cannot keep good characteristics in the whole frequency band. The main lobes would split and the gain would seriously decline when frequency is above 12 GHz. And the gaps between the internal structure, especially those in the feeding section formed in design and machining process, could cause serious effect on the performance of antenna. To overcome these problems, the Bézier curve instead of the exponential type curve and simplified feeding section that eliminates the wedges are utilized to design the DRHA. The problem that caused by the gaps in the feeding section is solved by extending the end of ridge into the short circuit board and eliminating the wages. The proposed antenna can achieve good radiation characteristics over the whole frequency band from 2 to 18 GHz. The VSWR is less than 2 and the gain is stable in the high frequency band. The proposed antenna is suitable for electromagnetic compatibility testing and the feed for reflector antennas.
Prediction of noise in multiconductor transmission lines excited by multiple radiation sources
Authors: Kim Eunha , Lee Jae‐Hyun 
Published: May 2018

AbstractThis study derives an analytic expression for voltages and currents in multiconductor transmission lines (MTL) excited by multiple radiation sources (MRS) at arbitrary locations. Modified telegrapher's equations are used to solve for the line voltage and line current in MTL with distributed voltage and current sources caused by the electric and magnetic coupling of external fields. The fields from MRS are considered as the incident fields on MTL. To verify our approach, we computed the terminal currents for both two transmission lines and four transmission lines excited by an electric dipole and compared the results with those of a commercial electromagnetic solver.
A hypoplastic macroelement formulation for single batter piles in sand
Authors: Li Zheng , Kotronis Panagiotis , Escoffier Sandra , Tamagnini Claudio 
Published: May 2018

SummaryBatter piles are widely used in geotechnical engineering when substantial lateral resistance is needed or to avoid the interference with existing underground constructions. Nevertheless, there is a lack of fast numerical tools for nonlinear soil‐structure interactions problems for this type of foundation. A novel hypoplastic macroelement is proposed, able to reproduce the nonlinear response of a single batter pile in sand under monotonic and cyclic static loadings. The behavior of batter piles (15°, 30°, and 45°) is first numerically investigated using 3D finite element modeling and compared with the behavior of vertical piles. It is shown that their response mainly depends on the pile inclination and the loading direction. Then, starting from the macroelement for single vertical piles in sand by Li et al (Acta Geotechnica, 11(2):373‐390, 2016), an extension is proposed to take into account the pile inclination introducing simple analytical equations in the expression describing the failure surface. 3D finite element numerical models are adopted to validate the macroelement that is proven able to reproduce the nonlinear behavior in terms of global quantities (forces‐displacements) and to significantly reduce the necessary computational time.
A parallel noninvasive multiscale strategy for a mixed domain decomposition method with frictional contact
Authors: Oumaziz Paul , Gosselet Pierre , Boucard Pierre‐Alain , Abbas Mickaël 
Published: May 2018

SummaryA multiscale extension for a parallel noninvasive mixed domain decomposition method is presented. After briefly exposing our noninvasive implementation of the Latin method, we present how the scalability of the algorithm is obtained by the partial verification of the constitutive law of the interfaces. We propose a new interpretation of the classical macrostrategy that imposes the overall balance of interface's forces. We also propose a new study of the macrostrategy that consists in enforcing the coarse continuity of the interfaces' displacement.
A time integration algorithm for a 3D constitutive model for SMAs including permanent inelasticity and degradation effects
Authors: Peigney M. , Scalet G. , Auricchio F. 
Published: May 2018

SummaryComponents based on shape‐memory alloys are often subjected to several loading cycles that result in substantial alteration of material behavior. In such a framework, accurate models, as well as robust and efficient numerical approaches, become essential to allow for the simulation of complex devices. The present paper focuses on the numerical simulation of quasi‐static problems involving shape‐memory alloy structures or components subjected to multiple loading‐unloading cycles. A novel state‐update procedure for a three‐dimensional phenomenological model able to describe the saturation of permanent inelasticity, including degradation effects, is proposed here. The algorithm, being of the predictor‐corrector type and relying on an incremental energy minimization approach, is based on elastic checks, closed‐form solutions of polynomial equations, and nonlinear scalar equations solved through a combination of Newton‐Raphson and bisection methods. This allows for an easy implementation of model equations and to avoid the use of regularization parameters for the treatment of nonsmooth functions. Numerical results assess the good performances of the proposed approach in predicting both pseudoelastic and shape‐memory material behavior under cyclic loading as well as algorithm robustness.
On continuous, discontinuous, mixed, and primal hybrid finite element methods for second‐order elliptic problems
Authors: Devloo P. R. B. , Faria C. O. , Farias A. M. , Gomes S. M. , Loula A. F. D. , Malta S. M. C. 
Published: May 2018

SummaryFinite element formulations for second‐order elliptic problems, including the classic H1‐conforming Galerkin method, dual mixed methods, a discontinuous Galerkin method, and two primal hybrid methods, are implemented and numerically compared on accuracy and computational performance. Excepting the discontinuous Galerkin formulation, all the other formulations allow static condensation at the element level, aiming at reducing the size of the global system of equations. For a three‐dimensional test problem with smooth solution, the simulations are performed with h‐refinement, for hexahedral and tetrahedral meshes, and uniform polynomial degree distribution up to four. For a singular two‐dimensional problem, the results are for approximation spaces based on given sets of hp‐refined quadrilateral and triangular meshes adapted to an internal layer. The different formulations are compared in terms of L2‐convergence rates of the approximation errors for the solution and its gradient, number of degrees of freedom, both with and without static condensation. Some insights into the required computational effort for each simulation are also given.
Management and outcome of neonates with a prenatal diagnosis of esophageal atresia type A: A population‐based study
Authors: Garabedian C. , Bonnard A. , Rousseau V. , Sfeir R. ,   CRACMO, Drumez E. , Michaud L. , Gottrand F. , Houfflin‐Debarge V. 
Published: May 2018

AbstractObjectiveEvaluate the neonatal management and outcomes of neonates with prenatal diagnosis of esophageal atresia (EA) type A.MethodsThis population‐based study was conducted using data from the French National Register for infants with EA born from 2008 to 2014, including all cases of EA type A. We compared prenatal and neonatal characteristics and outcomes in children with prenatal diagnosis of EA type A with those with a postnatal diagnosis until the age of 1.ResultsA total of 1118 live births with EA were recorded among which 88 (7.9%) were EA type A. Prenatal diagnoses were performed in 75 cases (85.2%), and counselling with a prenatal specialist was conducted in 84.8% of the prenatal group. Still within that group, the gestational age at delivery was significantly higher than in the postnatal group (36 [35‐38] versus 34 [32‐36] weeks; P = .048). Inborn births were more frequent in the prenatal group (86.1% vs 7.7%, P < .0001), and mortality and outcome were similar in both groups.ConclusionPrenatal diagnosis is high in EA type A, which enables to offer an antenatal parental counseling and which avoids postnatal transfers. Prognosis of EA types A does not appear to be influenced by the prenatal diagnosis.
Benefits of pulmonary rehabilitation in pediatric asthma
Authors: Kirkby Stephen , Rossetti Allison , Hayes Don , Allen Elizabeth , Sheikh Shahid , Kopp Benjamin , Patel Alpa 
Published: May 2018

AbstractIntroductionThere are limited studies evaluating the role of pulmonary rehabilitation (PR) in pediatric asthma.MethodsA retrospective chart review was performed of all pediatric patients with a diagnosis of asthma enrolled in PR. Demographics, medications, and clinical records were reviewed. In addition, PFTs, 6‐min walk test (6MWT), and patient/parent symptom and quality of life surveys before and after PR were evaluated.ResultsA total of 38 patients were enrolled in PR; 18 (47%) female and 20 (53%) male. Mean participant age was 11.33 ± 3.37 (range 4‐19) years. Twenty‐two (58%) were Caucasian and nine (24%) African American. Chart review was limited by incomplete data sets for many participants. Following PR, significant improvement was noted in mean 6MWT distance (1541 vs 1616 feet, P = 0.05) and FEV1 (89.9% of predicted versus 96.4%, P = 0.04). Survey instruments demonstrated improvement in several clinical factors, however, there was no significant change in weight following PR despite scheduled cardiovascular exercise and dietary counseling.ConclusionsStructured PR for pediatric patients with asthma can improve 6MWT distance and FEV1 as well as subjective measures of SOB and QOL, suggesting a role for PR in the chronic management of pediatric asthma. Further prospective investigation is needed to determine if PR has positive effects on other clinical parameters of asthma control and its overall impact on childhood obesity.
Plant‐mediated RNAi of grain aphid CHS1 gene confers common wheat resistance against aphids
Authors: Zhao Yanjie , Sui Xiaoyan , Xu Lanjie , Liu Guoyu , Lu Lihua , You Mingshan , Xie Chaojie , Li Baoyun , Ni Zhongfu , Liang Rongqi 
Published: May 2018

BACKGROUNDChitin is an important component of the insect exoskeleton and peritrophic membrane. Chitin synthase 1 (CHS1) is a key enzyme in the chitin synthesis pathway, and has a role in insect molting and growth. Plant‐mediated RNA interference (RNAi) has been used as a more target‐specific and environmentally safe approach to prevent and control agricultural insects. The aims of this study were to use grain aphid (Sitobion avanae) CHS1 as the target gene and to produce transgenic wheat lines for aphid control via plant‐mediated RNAi.RESULTSExpression levels of CHS1 changed at different developmental stages. After feeding on the representative T3 transgenic lines Tb5‐2 and Tb10‐3, CHS1 expression levels in grain aphid decreased by 50.29% and 45.32%, respectively; and total and molting aphid numbers reduced significantly, compared with controls. Consistent with this, aphid numbers in mixed natural populations reduced significantly in the respective T4 and T5 transgenic lines under field conditions, and T5 transgenic lines had higher grain weight compared with the unsprayed insecticide wild‐type and insecticide‐sprayed wild‐type.CONCLUSIONThese results indicate that plant‐mediated RNAi of the grain aphid CHS1 gene confers common wheat resistance against aphids. © 2018 Society of Chemical Industry
LL‐37 fragments have antimicrobial activity against Staphylococcus epidermidis biofilms and wound healing potential in HaCaT cell line
Authors: Saporito Paola , Vang Mouritzen Michelle , Løbner‐Olesen Anders , Jenssen Håvard 
Published: May 2018

Staphylococcus epidermidis is a common nosocomial pathogen able to form biofilms in indwelling devices, resulting in chronic infections, which are refractory to antibiotics treatment. Staphylococcal biofilms are also associated with the delayed reepithelization and healing of chronic wounds. The human cathelicidin peptide LL‐37 has been proven active against S. epidermidis biofilms in vitro and to promote wound healing. As previous studies have demonstrated that fragments of LL‐37 could possess an equal antibacterial activity as the parent peptide, we tested whether shorter (12‐mer) synthetic fragments of LL‐37 maintained the antibiofilm and/or immune modulating activity, aiming at the identification of essential regions within the LL‐37 parent sequence. Three fragments of LL‐37 displayed improved activity against S. epidermidis in terms of biofilm inhibition and eradication, a reduced cytotoxicity to human keratinocytes and erythrocytes. In addition, KR‐12 and VQ‐12V26 enhanced wound healing potential, relative to LL37. FK‐12 and KR‐12 are truncated version of the cathelicidin, previously reported as valid antimicrobials, whereas VQ‐12V26 is a single substituted LL‐37 fragment. Remarkably, the single substitution aspartic acid to valine in position 26 caused gain of antimicrobial function in the inactive VQ‐12 fragment. The combination of antibiofilm, wound healing potential, and low cytotoxicity makes KR‐12 and VQ‐12V26 promising therapeutic agents and lead compounds for further improvement and understanding of antibiofilm and wound healing properties.
Solubilized Carbohydrate Production by Acid‐Catalyzed Depolymerization of Cellulose in Polar Aprotic Solvents
Authors: Ghosh Arpa , Bai Xianglan , Brown Robert C. 
Published: May 2018

AbstractThis paper explores the effectiveness of several polar aprotic solvents, including 1,4‐dioxane, ethyl acetate, tetrahydrofuran (THF), methyl iso‐butyl ketone, acetone, acetonitrile, and gamma‐valerolactone (GVL), in depolymerizing cellulose into solubilized carbohydrates in the presence of acid catalyst. Whereas the yields of solubilized carbohydrates were strongly dependent on the polar solubility parameters of solvents, the use of acid catalyst substantially eliminated differences in the yields for the various solvents, which were in the range of 83–97%. The yields of levoglucosan and solubilized carbohydrates from cellulose in 1,4‐dioxane, THF, and acetone approached that of GVL, almost completely solubilizing cellulose within 1–7 min. Low initial rates of levoglucosan degradation caused these low polarity, low boiling point solvents to exhibit high stability and competitive yields of the anhydrosugar compared to high polarity and high boiling solvent such as GVL. The ease of recovery of low polarity, low‐boiling solvents makes them attractive media for production of solubilized carbohydrates, which the use of acid catalyst makes possible.