Polarization-Independent Metamaterial Analog of Electromagnetically Induced Transparency for a Refractive-Index-Based Sensor

Fan-Yi Meng,Qun Wu,Erni, D.,Ke Wu,Jong-Chul Lee IEEE 2012 IEEE transactions on microwave theory and techniqu Vol.60 No.10

<P>A polarization-independent metamaterial analog of electromagnetically induced transparency (EIT) at microwave frequencies for normal incidence and linearly polarized waves is experimentally and numerically demonstrated. The metamaterial consists of coupled “bright” split-ring resonators (SRRs) and “dark” spiral resonators (SRs) with virtually equal resonance frequencies. Normally incident plane waves with linear polarization strongly couple to the SRR, but are weakly interacting with the SR, regardless of the polarization state. A sharp transmission peak (i.e., the transparency window) with narrow spectral width and slow wave property is observed for the metamaterial at the resonant frequency of both, the bright SRR and the dark SR. The influence of the coupling strength between the SRR and SR on the frequency, width, magnitude, and quality factor of the metamaterial's transparency window is theoretically predicted by a two-particle model, and numerically validated using full-wave electromagnetic simulation. In addition, it is numerically demonstrated that the EIT-like metamaterial can be employed as a refractive-index-based sensor with a sensitivity of 77.25 mm/RIU, which means that the resonance wavelength of the sensor shifts 77.25 mm per unit change of refractive index of the surrounding medium.</P>

Comparison of diapause and non-diapause induced Orius sauteri (Hemiptera: Anthocoridae) based on a two-sex life table in the laboratory

Meng Sun,Bing Lü,Zhao-yun Lyu,Yang Zhang,Yi-Fan Zhai,Hao Chen,Li Zheng,Yi Yu 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.4

The flower bug Orius sauteri (Poppius) is commonly used as an effective biocontrol agent for controlling small pest populations in greenhouses in China. The impact of two temperature and photoperiod regimes (26 °C, L16:D8 h; 21 °C, L8:D16 h) on the life table of O. sauteri was studied in the laboratory using an age-stage, two-sex life-table method. The results showed that the low-temperature short-photoperiod regime resulted in significant increases of the developmental times of the egg, the first to fifth nymphal stages, and the total preadult stage. Female adult longevity was significantly increased, whereas male adult longevity was significantly decreased, under this regime. Furthermore, the adult preoviposition period (APOP), the total preoviposition period (TPOP), and the sex ratio were all increased under this regime. Fecundity decreased, whereas the mean generation time (T) increased, as temperature and photoperiod decreased. The intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (Ro) all increased as the temperature decreased under diapause induction. Based on the estimated data, the higher r value (0.06 d−1) occurred under the 26 °C, L16:D8 h regime, compared with 0.03 d−1, under the 21 °C, L8:D16 h regime. Thus, the results showed that reproductive diapause slowed O. sauteri population growth, about 50% reduction based on r. There is significant interest in using O. sauteri as a biological control agent against non-diapausing small pests, such as thrips, in greenhouses under short photoperiods. However, based on the current results, managers should consider maintaining a high temperature and long photoperiod to prevent reproductive diapause induction in O. sauteri. Such conditions should not have a detrimental effect on the greenhouse crops

A Highly Active Alpha Amylase from Bacillus Licheniformis: Directed Evolution, Enzyme Characterization and Structural Analysis

( Yi Han Liu ),( Shu Ai Fan ),( Xiao Guang Liu ),( Zhi Meng Zhang ),( Jian Ling Wang ),( Zheng Xiang Wang ),( Fu Ping Lu ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.7

The stability of Bacillus licheniformis alpha-amylase (BLA) under acid condition was enhanced through direct evolution using the error-prone polymerase chain reaction. One beneficial mutation site, H281I, was obtained in BLA. The specific activity of H281I was 161/352 U/mg, which was 62.6/27.5% higher than that of the wild-type (WT) (99/276 U/mg) at pH 4.5/6.5 and 95°C. The pH optimum for H281I was decreased about 1 unit, whereas no significant changes of optimum temperature and thermostability were observed compared with the wild type (WT). The kcat/Km value of H281I was 1.7-/1.4-fold higher at pH 4.5/6.5, respectively, than that of WT. The structure model analysis indicated that the H281I mutation altered the predicted interaction between the amino acid residues at 281 and 273, thus creating a conducive local environment for substrate binding, as reflected by its decreased Km, and consequently increased the specific activity.

The application of Large Eddy Simulation in designing the impellers of double-flow-conduits-sewage pump

QI Xue-yi,Liu Zai-lun,QI Chong,MENG Fan-zhang 한국전산유체공학회 2003 한국전산유체공학회 학술대회논문집 Vol.2003 No.10

Experimental and Simulation Study of PEMFC based on Ammonia Decomposition Gas as Fuel

Zhao, Jian Feng,Liang, Yi Fan,Liang, Qian Chaos,Li, Meng Jie,Hu, Jin Yi The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.1

Compared with hydrogen, ammonia has the advantages of high gravimetric hydrogen densities (17.8 wt.%), ease of storage and transportation as a chemical hydrogen storage medium, while its application in small-scale on-site hydrogen production scenarios is limited by the need for complex separation equipment during high purity hydrogen production. Therefore, the study of PEMFC, which can directly utilize ammonia decomposition gas, can greatly expand the application of fuel cells. In this paper, the output characteristics, fuel efficiency and the variation trend of hydrogen concentration and local current density in the anode channel of fuel cell with the output voltage of PEMFC fueled by ammonia decomposition gas were studied by experiment and simulation. The results indicate that the maximum output power of the hybrid fuel decreases by 9.6% compared with that of the pure hydrogen fuel at the same inlet hydrogen equivalent. When the molar concentration of hydrogen in the anode channel is less than 0.12, the output characteristics of PEMFC will be seriously affected. Employing ammonia decomposition gas as fuel, the efficiency corresponding to the maximum output power of PEMFC is approximately 47%, which is 10% lower than the maximum efficiency of pure hydrogen.

Adsorption of Lead(II) from Aqueous Solution by Two Modified Porous Chelating Resins Based on (3-Mercaptopropyl) Trimethoxysilane

Zhen-Zheng Wang,Hong-Dong Duan,Xia Meng,Yi-Fan Zhang,Hui-Min Qi 한국고분자학회 2016 Macromolecular Research Vol.24 No.9

Two novel types of thiol-based chelating resins were fabricated by modifying poly(2-hydroxyethyl methacrylate- co-glycerol dimethacrylate) (P(HEMA-GDMA)) and poly(2-hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) (P(HEMA-EGDMA)) with (3-mercaptopropyl) trimethoxysilane(MPS), and used to adsorb lead(II) from aqueous solution. The effects of initial lead(II) concentrations, solution pH, coexisting ions on adsorption of lead(II) were investigated. After modifying, the product P(HEMA-GDMA)-SH has excellent adsorption capacity (118.56 mg/g) for lead(II) at initial lead(II) concentration of 200 mg/L. The resins could easily be regenerated and were reused 6 times without significant loss of adsorption capacity. Besides, the presence of coexisting ions did not markedly influence the adsorption capacities of the resins. The results indicate that the functional thiol-based resins are efficient adsorbents for the removal of toxic lead(II) ions in water treatment.

Rich Se Nanoparticles Modified Mo-W18O49 as Enhanced Electrocatalyst for Hydrogen Evolution Reaction

Jun-hui Wang,Jia-Yao Tang,Jia-Yi Fan,Zeda Meng,Lei Zhu,오원춘 한국재료학회 2022 한국재료학회지 Vol.32 No.2

Herein a rich, Se-nanoparticle modified Mo-W18O49 nanocomposite as efficient hydrogen evolution reaction catalyst is reported via hydrothermal synthesized process. In this work, Na2SeSO3 solution and selenium powder are used as Se precursor material. The structure and composition of the nanocomposites are characterized by X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), EDX spectrum analysis and the corresponding element mapping. The improved electrochemical properties are studied by current density, and EIS analysis. The as-prepared Se modified Mo-W18O49 synthesized via Na2SeSO3 is investigated by FE-SEM analysis and found to exhibit spherical particles combined with nanosheets. This special morphology effectively improves the charge separation and transfer efficiency, resulting in enhanced photoelectric behavior compared with that of pure Mo-W18O49. The nanomaterial obtained via Na2SeSO3 solution demonstrates a high HER activity and low overpotential of -0.34 V, allowing it to deliver a current density of 10 mA cm2.

Facile Synthesis of g-C₃N₄ Modified Bi₂MoO₆ Nanocomposite with Improved Photoelectronic Behaviors

Zhu, Lei,Tang, Jia-Yao,Fan, Jia-Yi,Sun, Chen,Meng, Ze-Da,Oh, Won-Chun Materials Research Society of Korea 2021 한국재료학회지 Vol.31 No.11

Herein, a series of g-C₃N₄ modified Bi₂MoO₆ nanocomposites using Bi₂MoO₆ and melamine as original materials are fabricated via sintering process. For presynthesis of Bi₂MoO₆ an ultrasonic-assisted hydrothermal technique is researched. The structure and composition of the nanocomposites are characterized by Raman spectroscopy, X-ray diffraction (XRD), and high-resolution field emission scanning electron microscopy (SEM). The improved photoelectrochemical properties are studied by photocurrent density, EIS, and amperometric i-t curve analysis. It is found that the structure of Bi₂MoO₆ nanoparticles remains intact, with good dispersion status. The as-prepared g-C₃N₄/Bi₂MoO₆ nanocomposites (BMC 5-9) are selected and investigated by SEM analysis, which inhibits special morphology consisting of Bi₂MoO₆ nanoparticles and some g-C₃N₄ nanosheets. The introduction of small sized g-C₃N₄ nanosheets in sample BMC 9 is effective to improve the charge separation and transfer efficiency, resulting in enhancing of the photoelectric behavior of Bi₂MoO₆. The improved photoelectronic behavior of g-C₃N₄/Bi₂MoO₆ may be attributed to enhanced charge separation efficiency, photocurrent stability, and fast electron transport pathways for some energy applications.

Impact of a Glyphosate-Tolerant Soybean Line on the Rhizobacteria, Revealed by Illumina MiSeq

( Gui-hua Lu ),( Yin-ling Zhu ),( Ling-ru Kong ),( Jing Cheng ),( Cheng-yi Tang ),( Xiao-mei Hua ),( Fan-fan Meng ),( Yan-jun Pang ),( Rong-wu Yang ),( Jin-liang Qi ),( Yong-hua Yang ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.3

The global commercial cultivation of transgenic crops, including glyphosate-tolerant soybean, has increased widely in recent decades with potential impact on the environment. The bulk of previous studies showed different results on the effects of the release of transgenic plants on the soil microbial community, especially rhizosphere bacteria. In this study, comparative analyses of the bacterial communities in the rhizosphere soils and surrounding soils were performed between the glyphosate-tolerant soybean line NZL06-698 (or simply N698), containing a glyphosate-insensitive EPSPS gene, and its control cultivar Mengdou12 (or simply MD12), by a 16S ribosomal RNA gene (16S rDNA) amplicon sequencing-based Illumina MiSeq platform. No statistically significant difference was found in the overall alpha diversity of the rhizosphere bacterial communities, although the species richness and evenness of the bacteria increased in the rhizosphere of N698 compared with that of MD12. Some influence on phylogenetic diversity of the rhizosphere bacterial communities was found between N698 and MD12 by beta diversity analysis based on weighted UniFrac distance. Furthermore, the relative abundances of part rhizosphere bacterial phyla and genera, which included some nitrogen-fixing bacteria, were significantly different between N698 and MD12. Our present results indicate some impact of the glyphosate-tolerant soybean line N698 on the phylogenetic diversity of rhizosphere bacterial communities together with a significant difference in the relative abundances of part rhizosphere bacteria at different classification levels as compared with its control cultivar MD12, when a comparative analysis of surrounding soils between N698 and MD12 was used as a systematic contrast study.

Leaky-Wave Antennas Based on Noncutoff Substrate Integrated Waveguide Supporting Beam Scanning From Backward to Forward

Yue-Long Lyu,Xiao-Xin Liu,Peng-Yuan Wang,Erni, Daniel,Qun Wu,Cong Wang,Nam-Young Kim,Fan-Yi Meng Institute of Electrical and Electronics Engineers 2016 IEEE transactions on antennas and propagation Vol.64 No.6

<P>In this paper, we propose an approach to realize substrate integrated waveguide (SIW)-based leaky-wave antennas (LWAs) supporting continuous beam scanning from backward to forward above the cutoff frequency. First, through phase delay analysis, it was found that SIWs with straight transverse slots support backward and forward radiation of the -1-order mode with an open-stopband (OSB) in between. Subsequently, by introducing additional longitudinal slots as parallel components, the OSB can be suppressed, leading to continuous beam scanning at least from -40 degrees through broadside to 35 degrees. The proposed method only requires a planar structure and obtains less dispersive beam scanning compared with a composite right/left-handed (CRLH) LWA. Both simulations and measurements verify the intended beam scanning operation while verifying the underlying theory.</P>