bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of magnetoelectric multilayer laminate composites with series and parallel electrical connections
Authors: Yang G. , Talleb H. , Ren Z. 
Published: August 2017

AbstractThis paper investigates the performance of magnetoelectric composites composed of multilayer magnetostrictive and piezoelectric laminates in which the series and parallel electrical connections are applied. The multiphysics simulations have been performed according to the different longitudinal and transversal magnetization and polarization modes using a numerical model based on the finite element method and an analytical formulation based on the equivalent circuit model. The obtained results highlight the limitation of the analytical formulation to model the multilayer composites when an alternative opposing polarization between each neighboring piezoelectric layer is applied.
Passivity verification and enforcement—A review paper
Authors: Mahanta Protap Kumar , Yamin Nuzhat , Zadehgol Ata 
Published: August 2017

AbstractToday's advanced high‐speed technology requires building behavioral models of systems, from measured/simulated data, with increasingly higher operating frequencies. Different research efforts have come to light in literature for macromodeling, based on such types of data. Ensuring passivity is one of the most fundamental issues affecting system macromodeling, because system‐level performance can be unstable if even a single component of the system becomes nonpassive. Thus, from the computer‐aided design perspective, generation and provision of macromodels, while preserving passivity, is a significant challenge. In this paper, we carefully review novel techniques of passive macromodeling as well as their passivity verification and enforcement, from the early days to the present. We critically review the prominent methods in literature developed for macromodeling, and for verification and enforcement of passivity, and emphasize on their strengths and shortcomings.
Orthogonal strategy development using reversed macroporous resin coupled with hydrophilic interaction liquid chromatography for the separation of ginsenosides from ginseng root extract
Authors: Wu Yajun , Liu Jingjing , Gu Su , Lin Li , Chen Yingzhuang , Ma Ming , Chen Bo 
Published: August 2017

AbstractGinsenosides have been widely conceded as having various biological activities and are considered to be the active ingredient of ginseng. Nowadays, preparative high‐performance liquid chromatography is considered to be a highly efficient method for ginseng saponins purification and preparation. However, in the process of practical application, due to the complex and varied composition of natural products and relatively simple pretreatment process, it is likely to block the chromatographic column and affect the separation efficiency and its service life. In this work, an orthogonal strategy was developed; in the first‐dimension separation, reverse‐phase macroporous resin was applied to remove impurities in ginseng crude extracts and classified ginseng extracts into protopanaxatriol and protopanaxadiol fractions. In the second‐dimension separation, the obtained fractions were further separated by a preparative hydrophilic column, and finally yielded 11 pure compounds. Eight of them identified as ginsenoside Rh1, Rg2, Rd, Rc, Rb2, Rb1, Rg1, and Re by standards comparison and electrospray ionization mass spectrometry. The purity of these ginsenosides was assessed by high‐performance liquid chromatography with UV detection.
Magnetic micro‐solid‐phase extraction based on magnetite‐MCM‐41 with gas chromatography–mass spectrometry for the determination of antidepressant drugs in biological fluids
Authors: Kamaruzaman Sazlinda , Sanagi Mohd Marsin , Yahaya Noorfatimah , Wan Ibrahim Wan Aini , Endud Salasiah , Wan Ibrahim Wan Nazihah 
Published: August 2017

AbstractA new facile magnetic micro‐solid‐phase extraction coupled to gas chromatography and mass spectrometry detection was developed for the extraction and determination of selected antidepressant drugs in biological fluids using magnetite‐MCM‐41 as adsorbent. The synthesized sorbent was characterized by several spectroscopic techniques. The maximum extraction efficiency for extraction of 500 μg/L antidepressant drugs from aqueous solution was obtained with 15 mg of magnetite‐MCM‐41 at pH 12. The analyte was desorbed using 100 μL of acetonitrile prior to gas chromatography determination. This method was rapid in which the adsorption procedure was completed in 60 s. Under the optimized conditions using 15 mL of antidepressant drugs sample, the calibration curve showed good linearity in the range of 0.05–500 μg/L (r2 = 0.996–0.999). Good limits of detection (0.008–0.010 μg/L) were obtained for the analytes with good relative standard deviations of <8.0% (n = 5) for the determination of 0.1, 5.0, and 500.0 μg/L of antidepressant drugs. This method was successfully applied to the determination of amitriptyline and chlorpromazine in plasma and urine samples. The recoveries of spiked plasma and urine samples were in the range of 86.1–115.4%. Results indicate that magnetite micro‐solid‐phase extraction with gas chromatography and mass spectrometry is a convenient, fast, and economical method for the extraction and determination of amitriptyline and chlorpromazine in biological samples.
Patterns and drivers of deep chlorophyll maxima structure in 100 lakes: The relative importance of light and thermal stratification
Authors: Leach Taylor H. , Beisner Beatrix E. , Carey Cayelan C. , Pernica Patricia , Rose Kevin C. , Huot Yannick , Brentrup Jennifer A. , Domaizon Isabelle , Grossart Hans‐Peter , Ibelings Bastiaan W. , Jacquet Stéphan , Kelly Patrick T. , Rusak James A. , Stockwell Jason D. , Straile Dietmar , Verburg Piet 
Published: August 2017

AbstractThe vertical distribution of chlorophyll in stratified lakes and reservoirs frequently exhibits a maximum peak deep in the water column, referred to as the deep chlorophyll maximum (DCM). DCMs are ecologically important hot spots of primary production and nutrient cycling, and their location can determine vertical habitat gradients for primary consumers. Consequently, the drivers of DCM structure regulate many characteristics of aquatic food webs and biogeochemistry. Previous studies have identified light and thermal stratification as important drivers of summer DCM depth, but their relative importance across a broad range of lakes is not well resolved. We analyzed profiles of chlorophyll fluorescence, temperature, and light during summer stratification from 100 lakes in the Global Lake Ecological Observatory Network (GLEON) and quantified two characteristics of DCM structure: depth and thickness. While DCMs do form in oligotrophic lakes, we found that they can also form in eutrophic to dystrophic lakes. Using a random forest algorithm, we assessed the relative importance of variables associated with light attenuation vs. thermal stratification for predicting DCM structure in lakes that spanned broad gradients of morphometry and transparency. Our analyses revealed that light attenuation was a more important predictor of DCM depth than thermal stratification and that DCMs deepen with increasing lake clarity. DCM thickness was best predicted by lake size with larger lakes having thicker DCMs. Additionally, our analysis demonstrates that the relative importance of light and thermal stratification on DCM structure is not uniform across a diversity of lake types.
Flight planning: node‐based trajectory prediction and turbulence avoidance
Authors: Cheung Jacob C. H. 
Published: August 2017

ABSTRACTTo tackle the ever‐growing demand for air travel, the aviation industry has expressed great interest in assessing the impact weather uncertainty has on flight planning. However, due to the opacity of commercial flight planning systems, there has been an absence of a suitable research platform which weather centres could use to test and convey advancements in numerical weather prediction (NWP) to benefit operational flight planning.In this paper, a simple yet versatile trajectory prediction system that aims to bridge the gap between NWP centres and the industry is proposed. The proposed system is based on A*, a node‐based pathfinding approach which is simple to implement and configured to suit any requirements. Unlike analytical solutions, research findings from the proposed system can be readily implemented in commercial flight planning systems. An example of how clear air turbulence could have been considered before take‐off and avoided is presented.
Mutations in fetal genes involved in innate immunity and host defense against microbes increase risk of preterm premature rupture of membranes (PPROM)
Authors: Modi Bhavi P. , Teves Maria E. , Pearson Laurel N. , Parikh Hardik I. , Haymond‐Thornburg Hannah , Tucker John L. , Chaemsaithong Piya , Gomez‐Lopez Nardhy , York Timothy P. , Romero Roberto , Strauss Jerome F. 
Published: August 2017

AbstractBackgroundTwin studies have revealed a significant contribution of the fetal genome to risk of preterm birth. Preterm premature rupture of membranes (PPROM) is the leading identifiable cause of preterm delivery. Infection and inflammation of the fetal membranes is commonly found associated with PPROM.MethodsWe carried out whole exome sequencing (WES) of genomic DNA from neonates born of African‐American mothers whose pregnancies were complicated by PPROM (76) or were normal term pregnancies (N = 43) to identify mutations in 35 candidate genes involved in innate immunity and host defenses against microbes. Targeted genotyping of mutations in the candidates discovered by WES was conducted on an additional 188 PPROM cases and 175 controls.ResultsWe identified rare heterozygous nonsense and frameshift mutations in several of the candidate genes, including CARD6, CARD8, DEFB1, FUT2, MBL2, NLP10, NLRP12, and NOD2. We discovered that some mutations (CARD6, DEFB1, FUT2, MBL2, NLRP10, NOD2) were present only in PPROM cases.ConclusionsWe conclude that rare damaging mutations in innate immunity and host defense genes, the majority being heterozygous, are more frequent in neonates born of pregnancies complicated by PPROM. These findings suggest that the risk of preterm birth in African‐Americans may be conferred by mutations in multiple genes encoding proteins involved in dampening the innate immune response or protecting the host against microbial infection and microbial products.
A V‐band high dynamic range planar integrated power detector: Design and characterization process
Authors: Hannachi C. , Zouggari B. , Cojocaru Razvan I. , Djerafi T. , Tatu S. O. 
Published: August 2017

AbstractIn this paper, a high dynamic range V‐band power detector designed in thin film Miniature Hybrid Microwave Integrated Circuit (MHMIC) process is presented and characterized. The commercially available HSCH‐9161 millimeter‐wave zero bias GaAs Schottky diode is selected to manufacture the proposed power detector circuit, along with a broadband rectangular WR12 waveguide to microstrip transition, and an optimized microstrip impedance matching network. The design and characterization steps are described in detail to provide a consistent methodology to design high‐performance power detectors, while taking into account the accuracy, nonlinearity, and limitation of the measurement devices. The fabricated power detector prototype exhibits good input impedance matching (bandwidth of 3.8 GHz), high operational stability over 58.5–62 GHz frequency range, excellent sensitivity (−48 dBm), and high detection responsivity (peak of 8250 mV/mW at 61.2 GHz).
Measurement and nonlinear behavioral modeling of the dynamic bias current in an LTE‐A Chireix PA
Authors: Galaviz‐Aguilar José Alejandro , Chang Hsiu‐Chen , Martinez‐Rodriguez Francisco , Roblin Patrick , Núñez Pérez José C. 
Published: August 2017

AbstractThe measurement and modeling of the dynamic power dissipation of a dual‐input Chireix power amplifier driven by LTE modulated signals is reported to optimize its dynamic efficiency. Two memory cubic spline FIR and NARMA behavioral models are verified to accurately predict the measured instantaneous PA bias‐current and power dissipation as a function of the PA RF output power.
Frequency reconfigurable antenna for VHF/UHF digital TV reception on portable devices using switching matching networks
Authors: Liao Wen‐Jiao , Chou Shin‐Hui , Chen Yi‐Ane , Lee Yumin , Ho Min‐Chen , Wu Po‐Yi 
Published: August 2017

AbstractTo provide comprehensive coverage for digital TV reception on portable devices, a switchable matching network bank is proposed. Feasibility of this approach is demonstrated via a fully functional dongle‐sized tuner with a telescope antenna. Both RF and system level tests are conducted to validate the enhanced reception performance.
Design of single‐layered SIW inline eighth order filters based on two electric coupling structures
Authors: You Chang Jiang 
Published: August 2017

AbstractThis article presents 2 single‐layered inline substrate integrated waveguide filters with cross couplings based on 2 electric coupling structures, respectively. The coupling matrix method is employed to obtain the coupling coefficients and to guide the designs. The H‐shape and meandering electric coupling structures are used to generate electric cross couplings in the 2 filters, respectively. To validate the design, the 2 filters are simulated, fabricated and measured. Measured results show that the filter with H‐shape electric coupling structure has an insertion loss of 2.87 dB and is with a BW20dB‐to‐BW3dB ratio of 1.21, and the filter with meandering electric coupling structure has an insertion loss of 2.84 dB and is with a BW20dB‐to‐BW3dB ratio of 1.22.
60 GHz antenna array for millimeter‐wave wireless sensor devices using silver nanoparticles ink mounted on a flexible polymer substrate
Authors: Pourahmadazar J. , Denidni Tayeb A. 
Published: August 2017

AbstractThis paper demonstrates a mm‐wave high‐gain antenna design that is printed on a flexible polymer substrate using silver nanoparticles ranging from 50 to 200 nm in inkjet printing technology. Specifically, it shows that inkjet technology can leverage to fully fabricated antennas with this technology, where it provides both the characterization and preparation of an antenna. The initial fabrication problem addressed via ink formulation for printing a homogeneous layer with an excellent electrical conductivity. A planar series fed antenna array was analyzed by using the Transmission Line Model with tapering feed line structure. The excitation coefficients in both E and H planes follow a uniform aperture distribution. The realized antenna has 24 dBi gain, the side‐lobe level of elevation direction at the center frequency is lower than −15dB. In combination with the planar antenna structure, polymer substrate, and inkjet printing enables the production of structures with high gain that are widely applicable for mm‐wave wireless sensors and portable communication devices.
A compact D‐band I/Q mixer with improved transformer balun
Authors: Hou Debin , Hong Wei , Chen Jixin , Yan Pinpin , Xiong Yongzhong 
Published: August 2017

AbstractThis article presents a D‐band down‐conversion I/Q mixer using 0.13‐µm SiGe BiCMOS technology. The mixer is implemented with 2 Gilbert cells. The Lange coupler is for quadrature LO input and the transformer balun is for the differential RF input. The balance performance of the transformer balun is improved by adding a parallel capacitor or short‐circuit ground in the center‐tap of the differential outputs. Owing to the improved transformer balun, the mixer achieves a measured conversion gain of 10 to 8.2 dB when the RF frequency varies from 120 to 140 GHz and the LO frequency is fixed at 130 GHz. In the corresponding frequency range, the measured amplitude and phase imbalance between I and Q channels are ±0.5 dB and ±8°, respectively. The RF‐to‐LO isolation is over 40 dB. The proposed mixer also exhibits a compact size with the core size of 0.6 × 0.24 mm2.
Dual port disc monopole antenna for wide‐band MIMO‐based wireless applications
Authors: Nawaz Haq , Tekin Ibrahim 
Published: August 2017

AbstractIn this article, design and implementation of a wide‐band dual port monopole antenna based on single circular disc radiating element has been presented for Multi Input Multi Output (MIMO) configured 4G mobile and wireless communication systems. The proposed antenna uses a partial ground plane with two rectangular grooves which lie exactly below the respective 50 Ω microstrip feeding lines in order to obtain enhanced antenna's impedance bandwidth of 2‐6 GHz. A circular cut with 14 mm radius and centered at intersection of two partial rectangular ground planes is etched to reduce port to port RF coupling. The implemented dual port monopole antenna on 1.575 mm thick RT/Duroid 5880 substrate (with ɛ = 2.2, tangent loss = .001) provides >15 dB RF interport isolation for antenna's 10 dB impedance bandwidth of 2–6 GHz with measured gain variations of 2–6 dBi for each port excitation. In addition to interport isolation measurement for dual port antenna, the envelope correlation coefficient over the required frequency range has been calculated and plotted using S11, S22, and S21 measurement results to endorse the performance of dual port implemented antenna for diversity applications.
Reciprocity theorem based phased array hyperthermia applicator design
Authors: Lekka Eleni A. , Paschaloudis Konstantinos D. , Kyriacou George A. 
Published: August 2017

AbstractA novel method based on reciprocity theorem is elaborated for the estimation of phased array hyperthermia applicator complex excitation currents. For this purpose a detailed numerical model of the structure is constructed including all tissues and the antennas as metallic scatterers. The structure is simulated with a virtual‐test source at the tumor's center to yield the excitation currents at the port of the phased array through the corresponding scattering parameters. A simulation with these excitations verifies the focusing of electromagnetic energy over the tumor's area, which is improved by increasing the number of the array elements.
A 45‐ to 57‐GHz low‐power amplifier in 90 nm bulk CMOS
Authors: Su Guodong , Sun Lingling , Wen Jincai , Liu Jun , Gao Haijun , Zhang Le 
Published: August 2017

AbstractIn this article, a novel two‐stage 45–57 GHz low‐power amplifier is presented and implemented in a 90‐nm bulk CMOS technology. The crossing‐capacitor neutralization technique is adopted to improve the gain and isolation of the amplifier. Meanwhile, the low‐loss transmission line and on‐chip transformer are designed for the matching networks. The measurement results show that the proposed amplifier achieves 3‐dB gain bandwidth of 12 GHz, from 45 to 57 GHz. The maximum small‐signal gain of this amplifier is 7.2 dB at 48.4 GHz, and the output 1‐dB compression power is −6.8 dBm at 48.4 GHz. This amplifier consumes total power of 5.52 mW under 1.2 V voltage supply.
Wireless sensing of pressure from extracted capacitances using shielded external coils
Authors: Lee Doojin , Kim Kangwook 
Published: August 2017

AbstractThis paper presents a method to extract capacitances for pressure‐related applications. The external coils and internal circuit are inductively coupled to transmit power and to extract the capacitances in terms of the reflected impedance. The extracted frequency is 13.56 MHz, which is both the working frequency of the Near Field Communication (NFC) standards and the industrial, scientific and medical (ISM) band. The internal inductor with the shape of shorter helical coils is fabricated. The shielded external coils are designed using Ansys HFSS, and the shielded external coils make it more robust than unshielded external coils when the distance is increased. The measurement results show that the proposed method to extract the capacitances is realized under applied pressure from 1.02 to 1.32 bar. Based on the results, the pressure is wirelessly inferred from the extracted capacitances.
Toward image quality assessment in mammography using model observers: Detection of a calcification‐like object
Authors: Bouwman Ramona W. , Mackenzie Alistair , van Engen Ruben E. , Broeders Mireille J. M. , Young Kenneth C. , Dance David R. , den Heeten Gerard J. , Veldkamp Wouter J. H. 
Published: August 2017

PurposeModel observers (MOs) are of interest in the field of medical imaging to assess image quality. However, before procedures using MOs can be proposed in quality control guidelines for mammography systems, we need to know whether MOs are sensitive to changes in image quality and correlations in background structure. Therefore, as a proof of principle, in this study human and model observer (MO) performance are compared for the detection of calcification‐like objects using different background structures and image quality levels of unprocessed mammography images.MethodThree different phantoms, homogeneous polymethyl methacrylate, BR3D slabs with swirled patterns (CIRS, Norfolk, VA, USA), and a prototype anthropomorphic breast phantom (Institute of Medical Physics and Radiation Protection, Technische Hochschule Mittelhessen, Germany) were imaged on an Amulet Innovality (FujiFilm, Tokyo, Japan) mammographic X‐ray unit. Because the complexities of the structures of these three phantoms were different and not optimized to match the characteristics of real mammographic images, image processing was not applied in this study. In addition, real mammograms were acquired on the same system. Regions of interest (ROIs) were extracted from each image. In half of the ROIs, a 0.25‐mm diameter disk was inserted at four different contrast levels to represent a calcification‐like object. Each ROI was then modified, so four image qualities relevant for mammography were simulated. The signal‐present and signal‐absent ROIs were evaluated by a non‐pre‐whitening model observer with eye filter (NPWE) and a channelized Hotelling observer (CHO) using dense difference of Gaussian channels. The ROIs were also evaluated by human observers in a two alternative forced choice experiment. Detectability results for the human and model observer experiments were correlated using a mixed‐effect regression model. Threshold disk contrasts for human and predicted human observer performance based on the NPWE MO and CHO were estimated.ResultsGlobal trends in threshold contrast were similar for the different background structures, but absolute contrast threshold levels differed. Contrast thresholds tended to be lower in ROIs from simple phantoms compared with ROIs from real mammographic images. The correlation between human and model observer performance was not affected by the range of image quality levels studied.ConclusionsThe correlation between human and model observer performance does not depend on image quality. This is a promising outcome for the use of model observers in image quality analysis and allows for subsequent research toward the development of MO‐based quality control procedures and guidelines.