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Kinetic and mechanistic study of the f atom reaction with nitrous acid

JOURNAL Of PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 2004年第1-2期168卷 103-108页

作者： Bedjanian, Y Lelièvre, S Le Bras, G CNRS Lab Combust & Syst React F-45071 Orleans 2 France Univ Orleans F-45071 Orleans 2 France

The kinetics and mechanism of the reaction of nitrous acid (HONO) with f atoms have been studied using the mass spectrometric discharge-flow method at 298 K and at a total pressure of 130 Pa of helium. The rate coefficient of the reaction f + HONO --> products (1) was measured under pseudo-first order conditions from the kinetics of HONO decay in excess of f atoms: k(1) = (5.4 +/- 1.1) x 10(-11) cm(3) molecule(-1) s(-1) (quoted uncertainty includes estimated systematic errors). NO2 was detected as a product of reaction (1) and the reaction f + HONO --> Hf + NO2 (1 a) was found to be the main (if not unique) channel of reaction (1) under the experimental conditions of the study (k(1a)/k(1) = 1.0 +/- 0.1 (+/-2sigma)). These results indicate that reaction (1) can be a suitable titration reaction for the measurements of the absolute HONO concentrations under laboratory conditions. (C) 2004 Elsevier B.V. All rights reserved.

关键词： reaction kinetics rate constant nitrous acid HONO f

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Single Crystalline Transparent Conducting f, Al, and Ga Co-Doped ZnO Thin films with High Photoelectrical Performance

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ACS APPLIED MATERIALS & INTERfACES 2023年第18期15卷 22195-22203页

作者： Liu, Haixu Li, Hui Tao, Junlei Liu, Jia Yang, Jinzheng Li, Junjie Song, Jianmin Ren, Jie Wang, Min Yang, Shaopeng Song, Xin Wang, Yanfeng Hebei Agr Univ Coll Sci Baoding 071001 Peoples R China Hebei Univ Sci & Technol Sch Informat Sci & Engn Shijiazhuang 050018 Peoples R China Hebei Univ Prov Minist Coconstruct Collaborat Innovat Ctr Pho Baoding 071002 Peoples R China Hebei Univ Sci & Technol Sch Sci Shijiazhuang 050018 Peoples R China Applicat Changzhou Univ Sch Mat Sci Engn Jiangsu Engn Lab Light Elect Heat Energy Conv Changzhou 213164 Peoples R China

Transparent conductive film (TCf) is a material that integrates electrical conductivity and optical transparency. It is widely used as an electrode material in thin-film solar cells. However, considerable progress is needed to facilitate its high performance and low-cost preparation. In this study, a preparation scheme for Alf3 and Gaf3 co-doped ZnO (fAGZO) thin films was designed and implemented by magnetron sputtering (MS). The mutual restraint between the electrical properties and the wide spectrum transmission performance of ZnO films was resolved. first-principles calculations showed that the doped ZnO system had n-type conductivity and that the most stable structure was the fO-AlZn-GaZn system. The experimental results verified the theoretical predictions. Single crystalline ZnO transparent conducting films (ZnO-TCfs) of high quality were achieved by MS. After rapid thermal annealing (RTA) treatment, the mobility reached 49.6 cm2/V s, and the resistivity decreased to 3.82 x 10-4 omega cm. The AT was 90% between 380 and 1200 nm. furthermore, the application of the prepared fAGZO film in perovskite solar cells (PSCs) has been verified. Compared to the reference indium tin oxide film, the PSCs using the fAGZO film showed higher JSC and power conversion efficiency. These results demonstrate that MS combined with anion and cation co-doping provides an effective means of exploring high-quality and high-performance ZnO-TCfs.

关键词： ZnO transparent conductive film single crystalline f Al and Ga co-doping magnetron sputtering solar cell

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Combining Sequential Gaussian Simulation with Linear Regression to Develop Rehabilitation Strategies Using a Hydrometallurgical Process to Simultaneously Remove Metals, PCP, and PCDD/f from a Contaminated Soil

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SOIL & SEDIMENT CONTAMINATION 2021年第3期30卷 275-291页

作者： Metahni, Sabrine Coudert, Lucie Gloaguen, Erwan Tran, Lan Huong Guemiza, Karima Mercier, Guy Blais, Jean-francois Univ Quebec Ctr Eau Terre & Environm Inst Natl Rech Sci 490 Rue Couronne Quebec City PQ G1K 9A9 Canada Univ Quebec Univ Quebec Abitibi Temiscamingue Ctr Eau Terre Environm Inst Rech Mines & Environm Rouyn Noranda PQ Canada Univ Quebec Ctr Eau Terre Environm Inst Natl Rech Sci Quebec City PQ Canada Ctr Technol Residus Ind Abititi Temiscamingue Ctr Eau Terre Environm Rouyn Noranda PQ Canada

In this study, a new approach to predicting the ability of a hydrometallurgical process to simultaneously remove metal(loid)s, pentachlorophenol (PCP), and polychlorodibenzodioxins and furans (PCDD/f) from contaminated soil is developed. The remediation process consisted of attrition and alkaline leaching steps applied for the coarse (> 0.250 mm) and fine (< 0.250 mm) fractions, respectively. first, a contaminant granulometric distribution-CGD model was established from granulo-chemical analyses performed on 5 selected sampling points collected from the contaminated site to estimate the levels of metallic and organic (PCP, PCDD/f) contamination in the coarse (> 0.250 mm) and fine (< 0.250 mm) fractions of the entire sample (24) and reduce the analytical costs. The accuracy of the CGD model for each contaminant in both fractions was then evaluated by cross-validation. The CGD model, sequential Gaussian simulation (SGS), and linear regression analyses were combined to predict the ability of the attrition and leaching processes applied to the coarse (> 0.250 mm) and fine (< 0.250 mm) soil fractions to simultaneously remove As, PCP, and PCDD/f from contaminated soil, respectively. The results showed that the attrition process could effectively remove the contaminants below the regulation standards to allow the industrial use of the rehabilitated site, as the coarse fraction represents an average proportion of 84 +/- 2% of the total soil. However, the leaching process was ineffective in decontaminating the fine fraction (< 0.250 mm), which represented an average proportion of 14 +/- 1% of the total soil. Based on these results, the most suitable strategy for this site can be established and a methodological reference for similar studies in risk assessment can be provided.

关键词： Contaminated site heavy metals PCDD f sequential Gaussian simulations linear regression prediction

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Luminescent centres f and f⁺ in α-alumina detected by cathodoluminescence technique

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JOURNAL Of ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 2003年第1-3期133卷 55-63页

作者： Ghamnia, M Jardin, C Bouslama, M Univ Oran Es Senia Fac Sci Dept Phys LSMC Oran 31100 Algeria Univ Lyon 1 Dept Phys Mat F-69622 Villeurbanne France

alpha-Al2O3(0 0 0 1) single crystals have been investigated using cathodoluminescence (CL) technique and Auger electron spectroscopy (AES). The main luminescent centres such as f, f+ or Cr3+ activated during the irradiation of crystals by electrons of 4 keV energy were detected and discussed. CL intensity is shown to be highly dependent on both synthesis conditions and thermal annealing treatments. The air-annealing treatments at high temperature (1700degreesC reduce considerably the concentration of defects inducing a constant evolution of CL-signal of the band located at 330 nm attributed to f+ defects. On the contrary, crystals not annealed enough display a large increase of the f+ CL-signal during the electron irradiation. The f+ emission is also observed to be very sensitive to electron dose. (C) 2003 Elsevier B.V. All rights reserved.

关键词： f f+ centres cathodoluminescence (CL) alpha-Al2O3 defects

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Preparation and photocatalytic properties of DBD plasma f/N co-doping modified TiO2

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PHASE TRANSITIONS 2023年第3-4期96卷 216-232页

作者： Li, Xiong Zhang, Lianhong Wu, Hongbo Li, Qiang Hu, Cheng Southwest Petro Univ Sch Chem & Chem Engn Chengdu Peoples R China

In this thesis, TiO2 was first prepared by one-step hydrothermal method, then Hf was used as an f source, and TiO2 was treated by a DBD plasma reactor under an N-2 atmosphere, and the f/N co-modification of TiO2 was realized. In the visible light catalytic degradation experiment of 60 mg/L methylene blue, the overall catalytic performance of the catalyst treated with DBD plasma for 80 min was the best, with a degradation rate of 91% in 10 min and 96% in 60 min. Result Indication: DBD plasma treatment did not affect the phase structure and morphology of TiO2, but formed surface defects and surface adsorption on its surface, and successfully doped two non-metallic elements, f and N, thereby enhancing the photocatalytic degradation activity.

关键词： Photocatalysis plasma f N co-modification surface defects

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Quasi-classical trajectory approach to the stereo-dynamics of the reaction f+HO→Hf+O

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Science China Chemistry 2010年第4期53卷 927-932页

作者： Juan Zhao Yan Xu Xian Zhao QingTian Meng 1. College of Physics and Electronics Shandong Normal University Jinan 250014 China2. State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

Quasi-classical trajectory (QCT) calculations are employed for the reaction f + HO(0,0)→Hf + O based on the adiabatic potential energy surface (PES) of the ground 3A″triplet state. The average rotational alignment factor <P2(j′·k)> as a function of collision energy and the four polarization dependent generalized differential cross sections have been calculated in the center-of-mass (CM) frame, separately. The distribution P(θr) of the angle between k and j′, the distribution P(θr) of dihedral angle denoting k-k′-j′ correlation, and the angular distribution P(θr, Φr) of product rotational vectors in the form of polar plots are calculated as well. The effect of Heavy-Light-Heavy (HLH) mass combination and atom f’s relatively strong absorbability to charges on the alignment and the orientation of product molecule Hf rotational angular momentum vectors j′ is revealed.

关键词： product polarization f + HO reaction quasi-classical trajectory vector correlations

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A Reconfigurable Class-AB/f Power Amplifier for 0.1-4.2 GHz Multistandard Applications

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2021年第3期40卷 1111-1126页

作者： Mansour, Marwa Zekry, Abdelhalim Ali, Mohammed K. Shawkey, Heba Elect Res Inst ERI Microelect Dept Giza Egypt Ain Shams Univ Fac Engn Elect & Commun Dept Cairo Egypt Fayoum Univ Elect Engn Dept Al Fayyum Egypt Ulm Univ Inst Elect Devices & Circuits Ulm Germany

In this paper, a reconfigurable multi-mode Class-AB/f power amplifier (PA) is proposed for 0.1-4.2 GHz multistandard applications. The PA operates in linear mode (class-AB) for variable-envelope modulated signals and switching mode (class-f) for constant-envelope modulated signals. The proposed linear mode PA design is suitable for multi-band LTE, IOT, WSN and multi-standard Rf transmitter, while switching mode PA design can be used in multi-band IOT-LPWA and BLE (Bluetooth Low Energy) Rf transmitter. The proposed PA has a reconfigurable off-chip inter-stage and output matching networks over the specified frequency band, while the input stage is Complementary Current-Reuse common-gate with active shunt feedback configuration to achieve Ultra-Wideband (UWB) input matching. The proposed multi-mode PA is designed using a 130 nm CMOS process. Class-AB PA has a saturated output power of 23.5 dBm +/- 1 dB over 0.1-4.2 GHz, a power-added efficiency (PAE) of 41%, a third-order intercept point (OIP3) of 17 dBm, and adjacent channel power ratio (ACPR) of - 29.3 dBc for LTE 15 MHz channel bandwidth. The maximum PAE of 62.1% under the class-f operation is achieved at output power of 24.5 dBm. The PA occupies 0.64 mm(2)of chip area, while the estimated off-chip area is 13.3 mm(2). The proposed PA consumes 164 mW, and 16 mW in class-AB and class-f, respectively.

关键词： Class-AB f Multi-mode Power amplifier (PA) Radio frequency (Rf) Reconfigurable Rf transmitter

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Rate constants for the reactions of f atoms with H2 and D2 over the temperature range 220-960 K

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INTERNATIONAL JOURNAL Of CHEMICAL KINETICS 2021年第4期53卷 527-535页

作者： Bedjanian, Yuri CNRS Inst Combust Aerotherm React & Environm ICARE F-45071 Orleans 2 France

The kinetics of the reactions of f atoms with hydrogen and deuterium has been studied in a discharge flow reactor combined with an electron impact ionization quadrupole mass spectrometer at nearly 2 Torr total pressure of helium and in the temperature range 220-960 K. The rate constant of the reaction f + H-2 -> Hf + H (1) was determined using both relative rate method (using reaction f + Br-2 as a reference) and absolute measurements, monitoring the kinetics of f atom consumption in excess of H-2: k(1) = (1.24 +/- 0.09) x 10(-10) exp(-(507 +/- 23)/T) cm(3) molecule(-1) s(-1). The rate constant of the reaction f + D-2 -> Df + D (2) was measured under pseudo-first-order conditions in excess of D-2 over f atoms: k(2) = (8.47 +/- 0.42) x 10(-11) exp(-(670 +/- 16)/T) cm(3) molecule(-1) s(-1) (the uncertainties on both k(1) and k(2) represent precision at the 2 sigma level, the estimated total uncertainty on the rate constants being 15% at all temperatures). The kinetic isotope effect measured independently, k(1)/k(2) = (1.58 +/- 0.05) x exp((131 +/- 2)/T), was found to be in excellent agreement (within 7% in the temperature range of the work, T = 220-960 K) with the ratio of k(1) to k(2) calculated with the Arrhenius expressions for k(1) and k(2) determined in the study. The kinetic data from the present work are discussed in comparison with previous measurements and theoretical calculations.

关键词： f hydrogen KIE rate coefficient temperature dependence

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PREPARATIVE ISOLATION AND PURIfICATION Of fLAVONE C-GLYCOSIDES fROM THE LEAVES Of fICUS MICROCARPA L.f BY MEDIUM-PRESSURE LIQUID CHROMATOGRAPHY, HIGH-SPEED COUNTERCURRENT CHROMATOGRAPHY, AND PREPARATIVE LIQUID CHROMATOGRAPHY

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JOURNAL Of LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES 2010年第4期33卷 462-480页

作者： Wang, Xiaohong Liang, Yong Zhu, Licai Xie, Huichun Li, Hang He, Junting Pan, Man Zhang, Tianyou Ito, Yoichiro S China Normal Univ Sch Chem & Environm Guangzhou Guangdong Peoples R China Beijing Inst New Technol Applicat Beijing Peoples R China NIH Heart Lung & Blood Inst Bethesda MD 20892 USA

Combined with medium pressure liquid chromatography (MPLC) and preparative high performance liquid chromatography (perp-HPLC), high speed countercurrent chromatography (HSCCC) was applied for the separation and purification of flavone C-glycosides from the crude extract of leaves of ficus microcarpa L.f. HSCCC separation was performed on a two-phase solvent system composed of methyl tert- butyl ether-ethyl acetate -1-butanol-acetonitrile-0.1% aqueous trifluoroacetic acid at a volume ratio of 1:3:1:1:5. Partially resolved peak fractions from HSCCC separation were further purified by preparative HPLC. four well separated compounds were obtained and their purities were determined by HPLC. The purities of these peaks were 97.28%, 97.20%, 92.23%, and 98.40%. These peaks were characterized by ESI-MSn. According to the reference, they were identified as orientin (peak I), isovitexin-3''-O-glucopyranoside (peak II), isovitexin (peak III), and vitexin (peak IV), and yielded 1.2mg, 4.5mg, 3.3mg, and 1.8mg, respectively.

关键词： ficus microcarpa L f flavone C-glycosides high speed countercurrent chromatography medium pressure liquid chromatography preparative high pressure liquid chromatography

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Influences on performance in 3D analysis of linear induction motors with different transverse m.m.f. models in winding end-regions

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IET ELECTRIC POWER APPLICATIONS 2017年第8期11卷 1424-1431页

作者： Lv, Gang Zeng, Dihui Zhou, Tong Beijing Jiaotong Univ Sch Elect Engn Shangyuancun 3 Beijing Peoples R China

Since the three-dimensional (3D) analysis of linear induction motor (LIM) needs to consider the transverse end effect, the transverse magnetomotive force (m.m.f.) distribution model becomes significantly important. This study investigates the influences of different transverse m.m.f. models on operating characteristics of double-sided LIMs, and it also develops a novel m.m.f. model. first, four types of hypothetical distribution models are put into a 3D analytical method that considers the longitudinal and transverse end effects. Second, variations of the thrust, lateral and vertical forces with the models are comprehensively investigated in the possible operating regions. Besides, the calculated results are validated by finite elements method results and measurements in a prototype double-sided linear induction motor (DLIM). finally, the model presented in this study can be considered as a kind of optimal model for analysing DLIMs, and comparisons with other models in each operating region are mentioned.

关键词： linear induction motors machine windings finite element analysis LIM 3D analysis linear induction motor performance transverse m m f model winding end-regions LIM three-dimensional analysis transverse magnetomotive force distribution model transverse end effect hypothetical distribution model fEM model

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