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41.
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The thickness and the porosity of a deposit during ultrafiltration experiments are determined using an electrochemical method. Twenty microelectrodes are mounted flush to a ceramic plane membrane and maps of deposit thickness are determined for three inlet/outlet distributors configurations. Combining an electrochemical method and a step transient method, the determination of the thickness and the porosity of a particles deposit is performed. These local thickness and porosity values are analyzed thanks to wall shear stress local measurements obtained in a previous work [Sep. Sci. Technol. 37 (10) (2002) 2251]. The results emphasize the heterogeneity of the deposit thickness, especially in zones of low wall shear stress. Furthermore, the porosity values of the deposit are ranged between 0.3 and 0.8 as a function of the location at the membrane surface. 相似文献
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Magnetic field-induced orientation of a chiral side chain liquid crystalline polyacrylate(P-11) was studied by using IR dichroism. For the investigated P-11, it has been shown thatthe magnetic alignment takes place over the entire temperature range between its meltingpoint and clearing point and the orientation level is strongly temperature-dependent, thedevelopment with time of the magnetic orieatation follows an exponeotial-type relation,and the smectic phase state influences the thermal relaxation process in the absence of themagnetic field. 相似文献
45.
Krystyna Holderna-Natkaniec Ireneusz Natkaniec Weronika Kasperkowiak Elzbieta Sciesinska Jacek Sciesinski Edward Mikuli 《Journal of Molecular Structure》2006,790(1-3):94-113
FTIR and IINS spectra of 6-Furfurylaminopurine (6-FAP) and 6-Benzylaminopurine (6-BAP) taken at different temperatures have been analysed and compared with the spectra calculated by the ab initio DFT/B3LYP method and the semiempirical PM3 method in the isolated molecule approximation, for the tautomers N3-H, N7-H and N9-H, and dimers with hydrogen bonds. For 6-FAP the best agreement between the calculated and experimental (at 20 K) spectra has been found for the N9-H tautomer, whose structure was established by X-ray diffraction. For 6-BAP the analogous agreement for the N9-H tautomer structure has been poor and much better for the N7-H tautomer. The vibrational spectra calculated for dimers of the molecules studied involved in hydrogen bonds, permitted also an interpretation of the bands whose positions and FWHM in the FTIR spectra changed with temperature. 相似文献
46.
固相氯化法合成氯化聚乙烯的红外光谱研究 总被引:2,自引:0,他引:2
本文研究在不同条件固相氯化聚乙烯(CPE)的红外光谱,探讨了一步和两步氯化合成的CPE的结构差别,着重讨论了两步氯化的CPE结构特点。从观察表征结晶结构和—(CH_2)_n—链段氯分布的特征频率变化表明,低温固相氯化主要发生在无定形区,并且在CPE中形成高氯化和低氯化链段(或未氯化)的嵌段结构。在两步固相氯化时,晶区受到较大程度的破坏,氯化作用已不局限在无定形区,其结晶结构的破坏主要同第二步氯化程度有关,即使CPE氯含量相同,若前后两步氯化程度不同,结构有很大差异。 相似文献
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红外光谱法研究LB膜中的分子取向 总被引:1,自引:0,他引:1
The structure information of orientation and packing of molecular chains can be obtained from infrared transmission and reflection-absorbance (RA) spectra. In the present paper, on the basis of Umemura et al., their FORTRAN program of minicomputer was developed and can be run on 486 personal computer. By comparison of infrared transmission and RA intensities, surface enhancement factors and molecular orientation angle were calculated using the above program, and the influence of complex refractive index, angle of incidence, and thickness of LB film were discussed. These results are consistent with that of Umemura et al. 相似文献
49.
稳态双曲流场中液/液混合的粘性液滴哑铃分散模型 总被引:1,自引:0,他引:1
通过对稳态双曲流场中液/液混合体系分散相液滴所受分散作用力的分析,建立了粘性液滴的哑铃分散模型.趋于将两粘性液滴分开的分散作用力与粘度比、流场类型和强度、液滴半径、哑铃取向和尺寸有关.该模型解释了流场类型与分散作用的关系.流场类型对液滴的分散具有很大影响,在纯应变拉伸流场中分散作用力是简单剪切流场中的两倍,因而对于液滴的分散,拉伸流场较简单剪切流场更有效,这与以前的实验结论符合.当体系粘度比趋于无穷大时本模型转化为刚性哑铃分散模型 相似文献
50.
Tsun-Ren Chen 《Journal of Molecular Structure》2005,737(1):35-41
The absorption and emission properties of benzimidazol-2-yl-quinoline (BIQ) and bis (2-(benzimidazol-2-yl) quinolinato) zinc (ZnBIQ) a new emitter used for organic light emitting device (OLED) were reported. Exciplexes are observed for ZnBIQ with N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) system, in both electro- and photoluminescent processes. The identification of exciplex emission in co-evaporated and multi-layer ZnBIQ thin film was reported for the first time. The optical formation of the exciplex involves the excitation of a single molecule, followed by the relaxation of that exciton into a lower energy exciplex state. Both BIQ and ZnBIQ possess very high thermal stabilities and can be purified by subliming under the high vacuum condition. Devices consisting of ZnBIQ as the emitting layer have been fabricated, and the emission spectra of ZnBIQ-base devices gave a voltage-dependent spectrum, with the red emission observed (3-7 V), switching over to strong white emission as the bias was raised. 相似文献