bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent Advancements in Transition Metal‐Nitrogen‐Carbon Catalysts for Oxygen Reduction Reaction
Authors: Gu Wenling , Hu Liuyong , Li Jing , Wang Erkang 
Published: February 2018

AbstractIt remains a great challenge to replace platinum‐based catalysts with earth‐abundant materials to accelerate the sluggish oxygen reduction reaction (ORR) at the cathode, which is crucial for the future commercialization of fuel cells. Owing to the high catalytic activity, long‐term durability and low cost, transition metal‐nitrogen‐carbon (M−N/C, M=Fe, Co, Ni, Mn, etc) materials have been widely recognized as the most promising non‐precious metal catalysts (NPMCs) for ORR. In this review, the recent understanding of the ORR catalytic mechanism and the intrinsic nature of active sites is briefly introduced. Then, two crucial factors involved with careful selection of suitable M−N/C precursors and preferable control over the geometric structures of the catalysts are presented. Finally, we provide the insights into the remaining debates and challenges to illuminate the further development of ORR catalysts.
Extremal graphs for the k‐flower
Authors: Yuan Long‐Tu 
Published: February 2018

AbstractThe Turán number of a graph H, , is the maximum number of edges in any graph of order n that does not contain an H as a subgraph. A graph on vertices consisting of k triangles that intersect in exactly one common vertex is called a k‐fan, and a graph consisting of k cycles that intersect in exactly one common vertex is called a k‐flower. In this article, we determine the Turán number of any k‐flower containing at least one odd cycle and characterize all extremal graphs provided n is sufficiently large. Erdős, Füredi, Gould, and Gunderson determined the Turán number for the k‐fan. Our result is a generalization of their result. The addition aim of this article is to draw attention to a powerful tool, the so‐called progressive induction lemma of Simonovits.
Spectral modulation of stimulated Raman scattering signal: Beyond weak Raman pump limit
Authors: Lim Sohee , Chon Bonghwan , Rhee Hanju , Cho Minhaeng 
Published: February 2018

AbstractStimulated Raman scattering has recently been used in label‐free vibrational imaging studies of live cells. Important attempts to develop super‐resolution Raman imaging with intense Raman pump or decoherence beam have been made. However, the intense beams beyond weak stimulated Raman scattering limit could complicate spectral characteristics of Raman gain or loss signals. Here, the dependences of stimulated Raman loss signal on Raman pump intensity and pump‐probe delay time (Δt) are specifically investigated through both experimental and simulation studies. In the strong pump regime, a pronounced spectral modulation in stimulated Raman loss is observed at the Raman peaks of aromatic compounds with relatively large optical Kerr non‐linearity. We perform a numerical simulation for the coupled wave propagation to investigate the effect of cross‐phase modulation (XPM) on the stimulated Raman scattering (SRS). Our simulation involving both vibrationally resonant SRS and non‐resonant XPM effects in part accounts for the Δt‐dependent peak shift and spectral broadening as well as the appearance of a gain signal at negative time delays (Δt < 0). At the high pump intensity, it is found that the anti‐symmetric XPM signal with respect to the time zero (Δt = 0) cannot be selectively eliminated to produce pure SRS signal by time‐integration over Δt because of the increased interference term of the SRS and XPM at the Raman‐active frequency region. We believe that the experimental and simulation results discussed here would be of use in developing a super‐resolution coherent Raman imaging microscope in the near future.
Quantitative Raman spectroscopic study of the H2─CH4 gaseous system
Authors: Fang Jing , Chou I‐Ming , Chen Ying 
Published: February 2018

AbstractThe Raman spectra of pure H2 and CH4 gases and their 5 gaseous mixtures were collected at pressures from 1 to 40 MPa at ambient temperature. They were systematically analyzed in order to establish methodology for quantitative determination of composition and pressure of H2─CH4 bearing fluid inclusions. The peak positions of 4 vibrational bands of H2 in pure H2 gas decrease first and then increase after reaching their minima values at about 30 MPa. The wavenumbers of ʋ1 band of CH4 in pure CH4 gas decreases in wavenumber monotonically in the entire investigated pressure range. In H2─CH4 gaseous mixtures, both the peak positions of H2 and CH4 shift to lower wavenumbers with increasing pressure. The peak positions of ʋ1 band of CH4 can be used to determine the pressure of pure CH4 and CH4‐dominated fluids, where the peak position shifts are sufficiently large for precise pressure determination. The peak widths of H2 and CH4 in pure H2 and CH4 gases and H2─CH4 gaseous mixtures broaden as pressure increases. The peak area ratios and the peak height ratios between CH4 and H2 in H2─CH4 binary mixtures are sensitive to composition (i.e., molar ratio between CH4 and H2) but are almost independent of pressure. Thus, the peak area or peak height ratios can be used to determine the composition of H2─CH4 fluids. On the other hand, the peak height ratios of Q1(1) to Q1(3) bands in pure H2 gas or H2‐dominated gaseous mixtures are sensitive to pressure and insensitive to composition. Therefore, in H2‐dominated fluids, the relative peak heights of Q1(1) and Q1(3) of H2 is a better alternative for pressure determination. Based on our established Raman quantitative analysis method, we determined the composition and internal pressure of a natural H2─CH4‐bearing melt inclusion in quartz from Jiajika granite.
Anisotropic temperature‐dependence of optical phonons in layered PbI2
Authors: Zhang Zhaojun , Zheng Wei , Wang Weiliang , Zhong Dingyong , Huang Feng 
Published: February 2018

AbstractThe temperature‐dependence of wavenumbers of in‐plane E‐mode and out‐of‐plane A‐mode optical phonons of layered PbI2 were studied through analysis on its temperature‐dependent Raman spectra from 80 to 350 K. The temperature coefficient of the wavenumbers of in‐plane Eg phonon (−0.018 cm−1/K) and Eu phonon (−0.01 cm−1/K) are 3 and 10 times that of out‐of‐plane A1g phonon (−0.006 cm−1/K) and A2u phonon (−0.001 cm−1/K), respectively. Such anisotropy originated from the anisotropic thermal expansion of layered PbI2. These results will be beneficial for the design of PbI2‐based optoelectronic devices in the future.
Nondestructive prediction and visualization of plumpness in live Eriocheir sinensis using low‐field 1H magnetic resonance imaging
Authors: Zhang Hongcai , Mei Jun , Chen Shunsheng , Wu Xugan 
Published: February 2018

AbstractBACKGROUNDThe plumpness of hepatopancreas and gonad tissues in live Chinese mitten crabs (Eriocheir sinensis) depends on the grading scale and its commercial value. In this work, a low‐field T1‐weighted 1H magnetic resonance imaging (LF‐1H MRI) technique was developed to nondestructively analyze the plumpness of hepatopancreas and gonad tissues in live E. sinensis. Both male and female E. sinensis were characterized by two‐dimensional (2D) LF‐1H MRI. Moreover, a three‐dimensional (3D) LF‐1H MRI model that quantitatively integrated the total volume of lipid tissues in live E. sinensis was used.RESULTSThe results showed 2D LF‐1H MRI could accurately discriminate the plumpness of hepatopancreas and gonad tissues in live E. sinensis. The results of the 3D LF‐1H MRI model displayed that the lipid volume of E. sinensis could be used to quantify lipid accumulation in lipid tissues.CONCLUSIONLF‐1H MRI technology was successfully developed to accurately discriminate the development of E. sinensis hepatopancreas and gonad tissues in a nondestructive manner, indicating its application potential in grading commercial live crabs or advising crab farmers on breeding and fattening processes. © 2018 Society of Chemical Industry
Application of the ideal profile method to identify an ideal sufu for nonregular consumers
Authors: Chen Yan Ping , Chung Hau Yin 
Published: February 2018

AbstractBACKGROUNDSufu is a fermented soybean food with unique odor, flavor, and texture, which might not be appreciated by nonregular consumers. To identify the attributes that nonregular consumers appreciated, 12 commercial products bought from a Hong Kong market were tested by 113 consumers according to the ideal profile method (IPM), and rated on 22 attributes.RESULTSData provided from nonregular consumers were consistent at both panel and consumer levels. The predicted ideal profile received a higher hedonic score (7.0) than the tested products (6.0). Compared with commercial samples, the ideal sufu has low intensity in the attributes of fermented (aroma and flavor), moldy (aroma), and hard (texture), but high intensity in the soybean‐like (aroma and flavor) and sesame oil‐like (aroma and flavor) attributes.CONCLUSIONIPM could be used as an alternative approach to collect sensory profiles and preference data directly from consumers for product characterization. It could also be applied to identify the attributes that nonregular consumers appreciated. © 2018 Society of Chemical Industry
An auto‐classification procedure for concealed weapon detection in millimeter‐wave radiometric imaging systems
Authors: Işiker Hakan , Ünal İlhami , Tekbaş Mustafa , Özdemir Caner 
Published: February 2018

AbstractIn this work, we developed and proposed an auto‐classification technique for concealed weapon detection (CWD) for passive millimeter‐wave (PMMW) imaging systems. This technique has the ability to detect, classify and image hidden objects beneath the cloth of human targets. The algorithm was based on segmentation of normalized gray‐scale images for raw passive millimeter‐wave captured images and employing a decisive criterion for the classification of the targets. First, we tested our algorithm with the simulated data that were created numerically. Next, we examined our CWD technique with the measured data that were collected with PMMW radiometric imaging system at Marmara Research Center of TÜBİTAK. After producing the raw passive radar images, we have applied our passive CWD technique to the measured raw images to assess the performance of the algorithm. Produced edge‐detected final images of the concealed objects provide successful operation of the proposed technique.
Design of compact UWB monopole planar antenna with modified partial ground plane
Authors: Sahoo Swarnaprava , Mishra Laxmi Prasad , Mohanty Mihir Narayan , Mishra Rabindra Kishore 
Published: February 2018

AbstractIn this article, an improved double‐sided printed compact UWB monopole planar radiator and a method for improving its bandwidth for ultra‐wideband application is suggested. Results show that using right angled triangular slots on the partial ground plane under the microstrip feed line (a patch radiator with a compact dimension of 14.5 × 14.75 mm2) is achieved a bandwidth of 14.3 GHz. It varies from 3.2 to 17.5 GHz for S11 < −10 dB (VSWR < 2) with center frequency of 10.35 GHz, whereas the measured bandwidth 14 GHz varies from 3.1 to 17.1 GHz. Moreover, it has a stable radiation pattern across the whole bandwidth and attains an average gain of 4.2 dBi and highest gain of 6.4 dBi at 12.5 GHz.
77 GHz phase‐locked loop for automobile radar system in 90‐nm CMOS technology
Authors: Lin Yo‐Sheng , Lan Kai‐Siang , Wang Chien‐Chin , Lin Hsin‐Chen 
Published: February 2018

AbstractThe design and implementation of a 77 GHz phase‐locked loop (PLL) for automobile radar system in 90 nm CMOS technology is demonstrated. To enhance the operation frequency range of the voltage‐controlled oscillator in the PLL, reversely tunable LC source degeneration technique is adopted. To improve the frequency locking range of the divide‐by‐3 injection‐locked frequency divider in the PLL, a parallel inductor is used to parallel resonate the parasitic capacitance of the cross‐coupled transistors. In addition, a phase and frequency detector with enhanced D flip flops is used to effectively reduce the dead zone. The PLL consumes only 49.6 mW and exhibits an operation range of 2.4 GHz (76.8∼79.2 GHz) and reference sidebands of <–56 dBc. The chip area of the PLL is only 0.656 mm2 excluding the test pads.
A design methodology of envelope tracking power amplifier based on harmonic impedance tuning
Authors: Huang Fei , Chen Wenhua , Zhang Qian , Li Jing , Lv Guansheng , Feng Zhenghe 
Published: February 2018

AbstractA design methodology of utilizing the harmonic impedance tuning for the envelope tracking (ET) power amplifier (PA) is proposed in this letter. Owing to the assistance of harmonic tuning, the PA efficiency can be enhanced obviously. Experimental results show that PA prototype exhibits higher than 60% efficiency in the 7‐dB backoff power region and 36% average efficiency including envelope amplifier (EA) when driven by a 7‐dB PAPR long‐term evolution (LTE) signal.
An optimal operating frequency selection scheme for maximizing inductive power link efficiency
Authors: Cheng Yuhua , Xuan Dongdong , Su Xiang , Wu Wei , Wang Gaofeng 
Published: February 2018

AbstractImproving the efficiency of the inductive wireless power transfer (WPT) is an effective way to increase the power transfer distance, reduce the power exposure, and popularize the WPT application. If the geometrical sizes of the transmitting and receiving coils and the distance between them have been determined, an operating frequency exists to maximize the power transfer efficiency. In this work, a method to find this optimal frequency is introduced by virtue of analytical models of self‐ and mutual‐inductances and parasitic resistances and capacitances of the coils, and verified via simulations and measurements.
A new compact dual band CP antenna design
Authors: Saygin Hasan , Rafiei Vahid , Karamzadeh Saeid 
Published: February 2018

AbstractThis article presents a novel compact size (20 mm × 16 mm × 0.8 mm) Tai‐chi‐shaped antenna for wireless applications. Dual frequency operation (3.14–4.58 GHz and 4.97–6.53 GHz) is achieved by optimizing the antenna during designing steps. The antenna gives circulary polarization from 3.26 to 4.42 GHz and from 5.45 to 6.63 GHz frequency ranges. The 4.2 dBic stable gain is another evident advantage of proposed work.
Proposal of a fractal geometry with double similarity ratio for application in frequency selective surfaces with insensitive resonance frequency as a function of cell periodicity
Authors: Dantas Sergio R. , Cadineli Erico Braz , Campos Antonio L. P. Siqueira , Gomes Neto Alfredo 
Published: February 2018

AbstractIn this article, we proposed a new fractal geometry with double similarity for application in frequency selective surfaces (FSS) to obtain a structure insensitive to the resonance frequency as a periodicity function. Therefore, the bandwidth can changes only by changing the FSS periodicity, without any changes to the resonance frequency. Simulations were performed with the ANSYS HFSS commercial software and two prototypes were built for validation purposes. A good convergence between numerical and experimental results was obtained.
Compact wideband filtering microstrip crossover with separated operating frequencies
Authors: Zhang Bo , Yu Cuiping , Wu Yongle , Liu Yuanan 
Published: February 2018

AbstractIn this article, a compact wideband crossover with filtering performance is presented, with separated operating frequencies in two transmission paths. First, a novel crossover core circuit is presented based on cross‐shaped coupled lines. The odd‐even mode method is adopted to extract the transmission and isolation characteristics. Then, the loading sections are added in the core circuit to construct the proposed crossover, which can achieve enhanced filtering and isolating performances. The detailed design procedures of specific crossover are presented. Finally, a wideband filtering crossover centered at 2.03 and 3.54 GHz with measured bandwidths of 0.6 and 0.62 GHz is fabricated and measured, which verifies the proposed structures well. As to isolate these two signal paths by adopting conventional crossover with same frequency, the operating bandwidth of crossover should be wider than 2.11 GHz with center frequency of 2.78 GHz.
Efficient compact monopole antenna for on‐body applications
Authors: Hamsagayathri P. , Sampath P. 
Published: February 2018

AbstractThis research paper presents the design and implementation of low profile printed monopole antenna for Bio medical applications. The proposed antenna is designed for industrial, scientific, and medical frequency band (2.4–2.48 GHz). Four different patch geometries are considered and their performance is analyzed. The various parameter studies on ground length and slot width is performed and the precise dimensions are chosen. The slotted geometry along with stepped ground plane increases the current path and reduces the antenna size. To alleviate the impedance matching, proposed structure is endowed with stub tuning and hence minimum return loss −31 dB is attained. The proposed antenna is built on FR4 substrate and overall dimension (l, w, h) of this antenna is 20 mm × 20 mm × 1.6 mm. Antenna simulations are performed using ADS. The performance parameters of the proposed antenna is examined through simulations and verified with measured data. The measured result shows good concurrence with the simulated results. The proposed antenna exhibits good isolation of −35 dB between co‐ and cross‐polarization. It has stable gain of 2.92 dBi over the frequency range of 2.4–2.48 GHz and achieves 98.6% radiation efficiency.
Design of broadband leaky‐wave antenna based on permeability‐negative transmission line
Authors: Yan Shi , Li Yuan Chang 
Published: February 2018

AbstractIn this paper, a planar broadband leaky‐wave antenna (LWA) has been designed to achieve a full‐space scanning property with a stable high gain. The proposed LWA consists of 9 permeability‐negative transmission line unit cells. With the use of the unit cell, the space harmonic with n = −2 mode in a wide frequency band is generated, and thus a scanning range from −90° to 0° is realized when one port of the LWA is excited and the other is connected to a matched load. Considering the symmetry of the proposed antenna structure, the scanning range from 0° to 90° can be achieved by exchanging the excitation port. A prototype was fabricated and measured. The experimental results show that the proposed LWA has an impedance bandwidth for SWR ≤ 2 from 11 to 17.5 GHz, a scanning range from −85° to +85°, and a stable gain of 10.7 ± 2 dB.
Wideband and low RCS planar circularly polarized array based on polarization conversion of metasurface
Authors: Zheng Qi , Guo Chenjiang , Ding Jun 
Published: February 2018

AbstractIn this article, a planar wideband circularly polarized (CP) slot antenna array based on metasurface (MS) with low radar cross section (RCS) is proposed. The array is comprised of
CP MS‐based antennas fed with a sequentially rotated feeding network. For each CP antenna, the CP radiation is achieved due to polarization conversion of the MS. Simultaneously, the total MS patches of the array can be viewed as checkerboard composed of MS array and mirror array. A
phase difference between the MS units and the mirror units ensures RCS reduction. Simulated results demonstrate that about 34.6% operating bandwidth in the frequency of 4.3–6.1 GHz (both S11
–10 dB and AR < 3 dB). In addition, over 5 dB RCS reduction is obtained in the entire operation band under normal incidence with respect to the array without MS for both x‐ and y‐polarizations. The simulated monostatic RCS less than −30.9 dBsm is observed at 5.0 GHz. A prototype of the array is fabricated and measured, which are in good agreement with simulated results.
Effect of amino acid addition on the micelle formation of the surface‐active ionic liquid 1‐tetradecyl‐3‐methylimidazolium bromide in aqueous solution
Authors: Rojas Mabel , Miskolczy Zsombor , Biczók László , Pavez Paulina 
Published: February 2018

AbstractThe effect of 3 amino acids on the self‐assembly properties of the surface‐active ionic liquid: 1‐tetradecyl‐3‐methyl imidazolium bromide, [C14mim][Br], was studied in neutral and basic aqueous solution. The critical micelle concentrations were determined by different techniques, and the thermodynamic parameters of micellization (ΔG0mic, ΔH0mic, and ΔS0mic) were measured by isothermal titration calorimetry.The critical micelle concentration values decrease in the presence of all the amino acids used in this study. The most substantial effect was observed in the presence of L‐tryptophan at pH 12, due to the electrostatic and π‐π interactions with the imidazolium headgroup of the surfactant. Always entropy‐driven micellization occurred. Both the enthalpy and entropy changes upon association to micelles increased when the pH was enhanced from 7 to 12.1H NMR measurements demonstrated that among the used amino acids, L‐tryptophan interacts most strongly with the headgroup of the surfactant cation.The knowledge on the surfactant‐amino acid interactions significantly contributes to the deeper understanding of the effect of surfactants on the properties of peptides.
Registration‐free monitoring of multimode near‐circular shape profiles
Authors: Wang Kai , Li Jian , Tsung Fugee 
Published: February 2018

AbstractTraditional shape profile monitoring of product geometric features mostly focuses on one type or mode of shapes in the discrete‐part manufacturing. Little attention has been paid to monitoring of multimode shape profiles, where different modes of shapes appear in a sample in the batch production process. Motivated by a real example of a powder material production process, we exploit the statistical process monitoring of multimode near‐circular shape profiles. First, we develop a feature extraction approach that is invariant to shape rotation and thus requires no registration for a mixture of different modes of shape profiles. The extracted feature vectors capture shape features well, based on which different modes of shape profiles are separated into several clusters. This enables us to build a Gaussian mixture model for the multimodality in the feature vector space. In process surveillance, a control chart is constructed based on the likelihood ratio test for detecting shifts in both the proportions and the shape features of multimode near‐circular shape profiles. Numerical simulations and real case studies demonstrate the effectiveness of our proposed chart.
Development of Clay‐Based Films
Authors: Ebina Takeo 
Published: February 2018

AbstractPhyllosilicate (clay) is used as a filler to improve the thermal stability and gas barrier properties of plastic films. However, few film preparation trials used clays as the main component. Many researchers have studied clay‐based films (CBFs) that are heat‐resistant and have high gas barrier properties against various gases (such as oxygen, water vapor, and hydrogen) over a wide range of temperatures. An organic binder improves the film toughness, but increases gas permeation. CBFs are obtained by solution casting and show excellent incombustibility and electrical insulation. Moreover, transparent films, e. g. for optoelectronic applications, can be prepared using synthetic clay, which does not contain colored impurities. The water vapor barrier properties of CBFs were achieved using reduced‐charge smectite. Applications of CBF materials include food packaging, solar cell back sheets, hydrogen tanks, gaskets, water vapor barrier display films, substrates for printed electronics, thermal insulation, and electric insulation. Recent achievements in the field and future prospects are discussed.