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We present numerical results on the flame attachment in the downstream vicinity of the co-flow injector lip that separates the reactive fluids at injection. Two stability diagrams show the domains where the flame is anchored, blown off, or extinguished, in terms of separating plate thickness and injection velocities of both fluids. Different anchoring modes—stagnation point counter-flow holding or edge flame anchorage—are described, depending particularly on the plate rim thickness. To cite this article: C. Nicoli et al., C. R. Mecanique 334 (2006). 相似文献
94.
Guangjun Wen Jiayin Li Xiangzhen Xiong Tianmin Li Shenggang Liu 《International Journal of Infrared and Millimeter Waves》1997,18(9):1713-1724
A novel, highly accurate numerical synthetic technique for determining the complete dispersive characteristics of electromagnetic
modes in a spatially periodic structure is presented. The numerical method based on the coupling of the finite difference
method in time domain with the discrete fourier transform is applied to calculate the eigenfrequencies and eigenfield distribution
of a resonant cavity which is an appropriately shorted periodic slow wave circuit of N periods at both ends. The analytical
synthetic technique, which is based on the intrinsic characteristic of spatially periodic structure, is used to derive the
complete dispersion relation using the numerically measured resonances. The method was successfully applied for the case of
TMon modes in a coaxial corrugated waveguide and is applicable to slow wave structures of arbitrary geometry. 相似文献
95.
Stefano DUGHERI Nicola MUCCI Ilenia POMPILIO Giovanni CAPPELLI Costanza BOSSI Alessandro BONARI Giulio ARCANGELI 《色谱》2018,36(12):1311-1322
Long-term indoor-air limit for formaldehyde stipulated by the European Commission is 1 μg/m3,while the World Health Organization has set a threshold of 100 μg/m3 that should not be exceeded for more than 30 min. To date,however,only a few analytical techniques have been developed that can be used to detect formaldehyde at these very restrictive limits. Thus,there is a need to develop for comprehensive methods for analyzing airborne formaldehyde and other carbonyl pollutants in the ambient environment. The aim of this study is to develop a highly sensitive online automated preconcentration gas chromatographic method using large-volume injection with a programmed temperature vaporization injector for the analysis of airborne formaldehyde and ten other carbonyl compounds. The influence of several parameters,such as the maximum volume injected,programmed temperature vaporization transfer time and temperature,carrier gas flow rate,and type of packing material was investigated. After optimization,highly satisfactory results in terms of the absolute and methodological detection limits were achieved,i. e. as low as the μg/m3 level for all the carbonyl pollutants studied. A commercially available sampler,originally designed for active sampling,was evaluated as a passive sampling device;this optimized technique was applied to monitor the concentrations of carbonyl pollutants in the indoor air of ten public buildings in Florence. The strength of this methodology lies both in the low detection limits reached in the simultaneous analysis of a wide group of 2,4-dinitrophenylhydrazine derivatives,and the potential adaptability of this method to other gas chromatographic applications to achieve lower sensitivity. 相似文献
96.
静电纺丝技术制备TiO2@SiO2亚微米同轴电缆与表征 总被引:2,自引:0,他引:2
用静电纺丝技术成功制备出大量的TiO2@SiO2亚微米同轴电缆. 用TGA-DTA, XRD, SEM, TEM, EDS, FTIR分析技术对样品结构和组成进行了系统的表征. 结果表明, 得到的产物为TiO2@SiO2亚微米级同轴电缆, 以无定型SiO2为壳层, 晶态TiO2为芯层, 电缆平均直径450 nm, 壳层厚度90 nm, 电缆长度>300 μm, 同时在样品中发现个别纤维呈现管状结构, 对其形成机理进行了讨论. 相似文献
97.
The feeding-sample system used by microwave plasma torch atomic emission spectroscopy (MPT-AES) is the pneumatic nebulization
system; its efficiency, however, is not good. A newly built injector pump-ultrasonic nebulizer combination feeding-sample
system has been designed. Its performance was tested and compared with that of the pneumatic nebulization system. It can be
concluded that the newly built feeding-sample system can increase the spectral line intensity by about two to three times
and decrease the detection limit by about 2 to 10 times. Moreover, this newly built system can reduce the time taken washing
the sample cell from 30 min or so to about 10 min.
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Translated from Journal of JiLin University(Science edition), 2005, 43(4)(in Chinese) 相似文献
98.
A sensitive and reproducible residue method is described for the determination of cypermethrin and deltamethrin in fish eggs. The limit of determination of 0.0005 mg kg?1 is achieved using only a very small sample size; typical sample weights lie in the range of 0.1-1 g of fathead minnow or trout eggs. The method involves tissue homogenization (tube homogenizer) followed by hot acetonitrile extraction, then sequential C8, aluminum oxide, and silica gel clean-up. The clean-up is carried out in glass columns using cotton wool plugs in order to minimize potential sample contamination by plasticizers. Residues are determined by capillary chromatography using automated on-column injection with electron-capture detection. Confirmation of residues by gas chromatography-mass spectrometry using selected ion monitoring (SIM), is also described. 相似文献
99.
Preparation and properties of thermoresponsive and conductive composite fibers with core‐sheath structure
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Mei‐Fei Lin Trong‐Ming Don Fang‐Tzu Chang Shih‐Ru Huang Wen‐Yen Chiu 《Journal of polymer science. Part A, Polymer chemistry》2016,54(9):1299-1307
In this research, thermoresponsive and conductive fibers with core‐sheath structure were fabricated by coaxial electrospinning. For preparing the spinning sheath solution, poly‐(N‐isopropylacrylamide‐co‐N‐methylolacrylamide) (PNN) copolymer having thermoresponsive and cross‐linkable properties was synthesized by free‐radical polymerization using redox initiators; it was then mixed with the conductive poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) at different weight ratios in water. On the other hand, poly(butyl acrylate‐co‐styrene) (PBS) copolymer synthesized by emulsion polymerization was dissolved in chloroform and used as the spinning core solution. After electrospinning, the fibers were treated at 110 °C for 1 h to cross‐link the PNN portion in the sheath for strengthening the fibers. Well‐defined core‐sheath fibers were observed from SEM pictures; the outside and inside (core) diameters were 568 ± 24 and 290 ± 40 nm, respectively, as determined from TEM pictures. The fiber mats were further doped by DMSO to enhance their conductivity. For the fiber mat with the weight ratio of PEDOT:PSS/PNN at 0.20 in the sheath, its surface conductivity could reach 29.4 S/cm. In addition, the fiber mats exhibited thermoresponsive properties that both swelling ratio and electric resistance decreased with temperature. Furthermore, the fiber mats exhibited improved flexibility as evaluated via bending test. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1299–1307 相似文献
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