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海浪外观谱及其平衡域 被引量:1
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作者 吴克俭 宋金宝 孙孚 《海洋学报》 CAS CSCD 北大核心 1998年第1期21-24,共4页
定义了海浪能量的广义或n阶外观分布,导出了n阶海浪外观谱的解析形式,讨论了n阶外观谱的平衡域。结果表明,n阶外观谱的平衡域指数为-(3+n);平衡域指数上界为-3.任何波动现象,只要Fourier迭加原理和射线理论对... 定义了海浪能量的广义或n阶外观分布,导出了n阶海浪外观谱的解析形式,讨论了n阶外观谱的平衡域。结果表明,n阶外观谱的平衡域指数为-(3+n);平衡域指数上界为-3.任何波动现象,只要Fourier迭加原理和射线理论对它们的描述足够准确,则本文的结论皆成立。 展开更多
关键词 外观谱 内频 平衡域 海浪 风浪频
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海浪外观波数谱与谱宽度最优确定
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作者 杨永增 张杰 冷秀华 《黄渤海海洋》 CSCD 1999年第3期26-30,共5页
本文将外频谱转化为外观波数谱并设计了计算处理格式,提出了一种谱宽度参量的优化方法,为进一步研究海浪特征资料提取谱值和应用奠定基础。数值试验验证了此方法的可行性,但在高海况下风浪过程复杂,优化出的谱宽度偏大。
关键词 外观谱 宽度 最速下降法 海浪
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均匀介质n维随机波动的空间结构 被引量:2
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作者 吴克俭 孙孚 宋金宝 《海洋学报》 CAS CSCD 北大核心 1998年第2期14-19,共6页
研究了均匀介质中n维随机波动的空间结构.导出了外观振幅、波数和相位的联合分布,据此分布,所有与空间有关的波要素的统计分布皆可导出.定义了外观波数谱并得到了其平衡区指数的上界为一(n+2).二维时,海浪外观波数谱平衡区... 研究了均匀介质中n维随机波动的空间结构.导出了外观振幅、波数和相位的联合分布,据此分布,所有与空间有关的波要素的统计分布皆可导出.定义了外观波数谱并得到了其平衡区指数的上界为一(n+2).二维时,海浪外观波数谱平衡区指数的上界与Phillips通过动力学分析导出的Fourier波数谱平衡区指数完全一样。 展开更多
关键词 随机波动 空间结构 外观波数 均匀介质 波浪
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Reactive Extraction of Nicotinic Acid with Trialkylamine in n-Octanol 被引量:2
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作者 李德亮 于飞 常志显 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2012年第5期843-848,共6页
The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to ded... The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to deduce the reaction mechanism. It was found that N235/n-octanol was an efficient extractant for extracting nicotinic acid. The favorable operation conditions were equilibrium aqueous pH 4.2 to 5.5 and initial N235 concentration<0.42 mol·L-1 . The reaction processes included the reaction between neutral N235 and neutral NA and the reaction between protonated N235 and anionic NA. Based on the mass action law and some assumptions, an expression for distribution coefficient D was proposed. The apparent extraction equilibrium constants were calculated by fitting the experimental data and the results were satisfactory. 展开更多
关键词 nicotinic acid reactive extraction trlalkylamlne proton-transter
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Natural Rubber-Grafted-Poly (Methyl Methacrylate): Influence of Coagulating Agents on Properties and Appearances 被引量:1
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作者 Rohani Abu Bakar M. S. Fauzi 《Journal of Chemistry and Chemical Engineering》 2012年第11期962-966,共5页
Graft copolymers of MMA (methyl methacrylate) with NRL (natural rubber latex) referred to as NR-g-PMMA have been prepared using CHP (cumene hydroperoxide)/TEPA (tetraetbylenepentamine) redox initiator. 1H NMR ... Graft copolymers of MMA (methyl methacrylate) with NRL (natural rubber latex) referred to as NR-g-PMMA have been prepared using CHP (cumene hydroperoxide)/TEPA (tetraetbylenepentamine) redox initiator. 1H NMR (proton nuclear magnetic resonance) and FTIR (Fourier transform infrared) analysis have confirmed the occurrence of graft copolymerisations of MMA onto NR that containing 30% and 50% of MMA monomer. The influence of coagulating agents such as formic acid, sulfuric acid and boiling water on the coagulation of NR-g-PMMA latices were investigated. These types of coagulating agent formed compact coagulum and the effect of NR-g-PMMA compounds on cure characteristics, physical properties and appearances were reported. 展开更多
关键词 Natural rubber-grafted-poly (methyl methacrylate) coagulating agent physical properties color appearance
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Microstructure and microwave dielectric properties of CaO-B_2O_3-SiO_2 glass ceramics with various B_2O_3 contents 被引量:8
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作者 韦鹏飞 周洪庆 +2 位作者 朱海奎 戴斌 王杰 《Journal of Central South University》 SCIE EI CAS 2011年第5期1359-1364,共6页
The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 (CBS) glass ceramics were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diff... The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 (CBS) glass ceramics were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 (20-500℃), a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 (measured at 9.7 GHz) are obtained for CBS glass ceramics containing 35%-B203 (mass fraction) sintered at 850 ℃ for 15 min. 展开更多
关键词 CAO-B2O3-SIO2 B2O3 content Fourier transform infrared spectroscopy MICROSTRUCTURE dielectric properties
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Comparisons of Two Cloud-Detection Schemes for Infrared Radiance Observations 被引量:1
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作者 XU Dong-Mei HUANG Xiang-Yu +1 位作者 LIU Zhi-Quan MIN Jin-Zhong 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第4期358-363,共6页
The cloud-detection procedure developed by McNally and Watts(MW03) was added to the Weather Research and Forecasting Data Assimilation System. To provide some guidelines for setting up cloud-detection schemes, this st... The cloud-detection procedure developed by McNally and Watts(MW03) was added to the Weather Research and Forecasting Data Assimilation System. To provide some guidelines for setting up cloud-detection schemes, this study compares the MW03 scheme to the Multivariate and Minimum Residual(MMR) scheme for both simulated and real Advanced Infrared Sounder(AIRS) radiances. Results show that there is a high level of consistency between the results from simulated and real AIRS data. As expected, both cloud-detection schemes perform well in finding the cloud-contaminated channels based on the channels' peak levels. The clouddetection results from MW03 are sensitive to the prescribed brightness temperature innovation threshold and brightness temperature gradient threshold. When increasing the brightness temperature innovation threshold for MW03 to roughly eight times the default threshold, the two cloud-detection schemes produce consistent data rejection distributions overall for high channels. MMR generally retains more data for long-wave channels. For both cloud-detection schemes, there is a high level of consistency between the cloud-free pixels and the visible/near-IR(Vis/NIR) cloud mask. 展开更多
关键词 AIRS WRF data assimilation system cloud detection brightness temperature departure
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Synthesis of Macro-Mesostructured γ-Al_2O_3 with Large Pore Volume and High Surface Area by a Facile Secondary Reforming Method 被引量:2
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作者 Meng Xiuhong Duan Linhai +2 位作者 Xie Xiaohua Wang Qiang Wang Haiyan 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第2期20-28,共9页
Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the ... Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetry (TG). The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume (2.175 cm^3/g), high surface area (237.8 m^2/g), and low bulk density (0.284 g/mL). 展开更多
关键词 Γ-AL2O3 macro-mesostructured reforming method large pore volume high surface area.
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Microscopic study of binary mixtures between pyrrolidinium bis(triflorosulfonyl)imide and dimethyl sulfoxide/acetonitrile
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作者 Hamad Ashraf Yu Zhou +2 位作者 Jing Xu Khalil Ahmad Zhi-Wu Yu 《Science China Chemistry》 SCIE EI CAS CSCD 2016年第5期578-586,共9页
Molecular interactions of a representative pyrrolidinium-based ionic liquid 1-butyl-l-methyl-pyrrolidinium bis(triflorosulfonyl)- imide ([BMPyrr][TFSI]) with dimethyl sulfoxide (DMSO) and acetonitrile (AN) hav... Molecular interactions of a representative pyrrolidinium-based ionic liquid 1-butyl-l-methyl-pyrrolidinium bis(triflorosulfonyl)- imide ([BMPyrr][TFSI]) with dimethyl sulfoxide (DMSO) and acetonitrile (AN) have been analyzed in this work. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and density functional theory (DFT) calculations are used in the investigation, while excess infrared spectra and two-dimensional correlation spectroscopy are used to explore the data in detail. It has been found that the molecular solvents can interact with TFSI- (mainly with S=O and weakly with S-N-S group). AN interacts feebly with BMPyrr+ as compared with the strong interaction of DMSO. The strength of the interactions depends on the electron donating ability of the solvent. Upon mixing, hydrogen bonds regarding C-Hs in cation and S-N-S in anion are weakened, while that regarding S=O in anion is strengthened. Among the C-Hs which are connected directly with the N of the cation, Cl-H is the main interaction site for both DMSO and AN. This means that Cl-H is the most acidic hydrogen in pyrrolidinium cation. 展开更多
关键词 ATR-FTIR DFT calculations excess infrared spectrum two-dimensional correlation spectroscopy ionic liquid hydrogen bond
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