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排序方式: 共有121条查询结果,搜索用时 15 毫秒
31.
Gomes AC Cafer LD Homem-de-Mello P Coutinho-Neto MD Gaubeur I 《Journal of colloid and interface science》2012,367(1):370-377
The adsorption of SPADNS (trisodium salt of 2-(p-sulfophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid) onto resins XAD 2, XAD 7 and silica gel was studied in the presence and in the absence of the cationic surfactant CTAB (cetyl trimethylammonium bromide). At a ratio of 2.5 CTAB to 1 SPADNS, the surfactant caused a marked increase in SPADNS adsorption. The experimental results for adsorption versus time were applied on the basis of three kinetic models (pseudo-first-order Lagergren, pseudo-second-order, and intraparticle diffusion). The interaction between CTAB and SPADNS was investigated using spectrophotometric, conductometric, and computational techniques. Theoretical results point to the formation of an ion pair between CTAB and SPADNS that influences the solution spectra, in agreement with conductometric and spectrophotometric data. 相似文献
32.
The collocation method based on quartic B‐spline interpolation is studied for numerical solution of the regularized long wave (RLW) equation. The time‐split RLW equation is also solved with the quartic B‐spline collocation method. Numerical accuracy is tested by obtaining the single solitary wave solution. Then, interaction, undulation and evolution of solitary waves are studied. Solutions are compared with available results. Conservation quantities are computed for all test experiments. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2007 相似文献
33.
Toshiki Nakata Hisashi Miyafuji Shiro Saka 《Applied biochemistry and biotechnology》2006,130(1-3):476-485
The water-soluble portion and precipitates obtained by supercritical (SC) water treatment of microcrystalline cellulose (Avicel)
were enzymatically hydrolyzed. Glucose could be produced easily from both substrates, compared with the Avicel. Therefore,
SC water treatment was found to be effective for enhancing the productivity of glucose from cellulose by the enzymatic hydrolysis.
It is also found that alkaline treatment or wood charcoal treatment reduced inhibitory effects by various decomposed compounds
of cellulose on the enzymatic hydrolysis to achieve higher glucose yields. Furthermore, glucose obtained by SC water treatment
followed by the enzymatic hydrolysis of cellulose could be converted to ethanol by fermentation without any inhibition. 相似文献
34.
M. Hirotani T. E. Sale J. Woodhead J. S. Roberts P. N. Robson T. Saka T. Kato 《Journal of Crystal Growth》1997,170(1-4):390-393
High power and high speed surface emitting graded index separate confinement heterostructure (GRINSCH) LEDs with an InGaAs quantum well grown by metalorganic vapour phase epitaxy have been realized. The speed and the output power are affected by the thickness of the spacer layers separating the quantum well structure from the graded index layers and the growth sequence of the interface. A performance of 7.4 mW output power and 118 MHz speed, at 945 nm emitting wavelength, has been achieved when the spacer layer thickness is 50 Å with 30 s growth halts. The quantum and power efficiencies are 11% and 7.5%, respectively. 相似文献
35.
A calculation method of the atomic flux divergence due to electromigration, AFDgen, has been proposed considering two-dimensional distributions of current density and temperature and also simply considering the line structure of not only polycrystalline line but also bamboo line. The validity of AFDgen for bamboo lines has been verified in comparison of void formation calculated by using AFDgen with experimental results, and it has been shown that void formation in bamboo line is able to be predicted by using AFDgen. In this study, angled bamboo lines are treated for prediction of hillock formation, and hillock formation predicted by using AFDgen is compared with that measured in experiment. In addition to the verification of void prediction, the usefulness of the prediction method for electromigration damage using AFDgen is discussed in more detail. 相似文献
36.
The chemical conversion of cellulose as treated in supercritical methanol was studied using a batch-type reaction vessel at temperatures from 220 to 450°C and pressures from 14 to 72MPa. Supercritical methanol treatment at 350°C and 43MPa for 7min was sufficient to convert microcrystalline cellulose (avicel) to the methanol-soluble. To study the kinetics of the decomposition of cellulose, the decomposition rate constants were obtained, and rapid increase was observed at about 270°C which was about 30°C higher than the critical temperature of methanol. The main products from cellulose decomposition were methylated cellotriose, methylated cellobiose, methyl - and -D-glucosides, levoglucosan and 5-hydroxymethylfurfural. Monomeric compounds such as methyl - and -D-glucosides were stable in supercritical methanol, allowing high yields of monomeric products by supercritical methanol treatment. Based on these results, a pathway of cellulose decomposition treated in supercritical methanol was proposed. These findings suggest that the supercritical methanol treatment of various cellulosic materials may be suitable to obtain useful chemicals and liquid fuels without using fossil resources. 相似文献
37.
Yuxin Sun Daining Fang Masumi Saka Ai Kah Soh 《International Journal of Solids and Structures》2008,45(7-8):1993-2013
In this study, the vibration phenomenon during pulsed laser heating of a micro-beam is investigated. The beam is made of silicon and is heated by a non-Gaussian laser beam with a pulse duration of 2 ps, which incites vibration due to the thermoelastic damping effect. The coupling between the temperature field and stress field induces energy dissipation and converts mechanical energy into heat energy, which is irreversible. An analytical–numerical technique based on the Laplace transform is used to calculate the vibration of the deflection and thermal moment. A general algorithm of the inverse Laplace transform is developed. The validation of this algorithm is obtained through comparison with numerical results obtained by the FEMLAB software package. The effect of laser pulse energy absorption depth is studied. The size effect and the effect of different boundary conditions are also analyzed. Finally, the damping ratio and resonant frequency shift ratio of beams due to the air damping effect and the thermoelastic damping effect are compared. 相似文献
38.
Application of wavelet transform to hologram analysis: three-dimensional location of particles 总被引:1,自引:0,他引:1
Cristina Buraga-Lefebvre Sbastien Coëtmellec Denis Lebrun Cafer
zkul 《Optics and Lasers in Engineering》2000,33(6):409-421
The wavelet analysis provides an efficient tool in numerous signal-processing problems and has been implemented in optical processing techniques, such as in-line holography. When the diffraction pattern recorded on a hologram is analyzed by means of a wavelet transform, the 3-D location of small particles can be determined very accurately. The diffraction process can, in fact, be interpreted as a convolution with a family of wavelet functions, or, merely, as a wavelet transform. The scale parameter of the wavelet family is related to the axial distance z that the wave propagates. The original field is then reconstructed by searching for the optimum value of the scale parameter which produces a maximum of the wavelet transform modulus. The technique proposed is implemented and experimental results are presented. 相似文献
39.
Sherry A. Southerland Louis Nadelson Scot Sowell Yavuz Saka Murat Kahveci Ellen M. Granger 《School science and mathematics》2012,112(8):483-494
The aim of this research is to describe the development of the Science Teachers’ Pedagogical Discontentment Scale, an instrument that measures the discontentment that arises in teachers as they recognize a mismatch between their own pedagogical beliefs and goals and their actual classroom practices. From a conceptual change perspective, we explore the meaning of pedagogical discontentment and discuss its role in shaping teachers’ receptivity to messages of reform. We present an instrument that can be used to measure teachers’ pedagogical discontentment, an instrument that will allow science educators to better describe the affective states of teachers as they enter professional development experiences. The items for the initial instrument were derived from a series of interviews with practicing teachers; from these interviews, a group of 42 items were designed around a group of five subscales. The final instrument, revised after two rounds of field testing, includes 21 multiple‐choice items clustered around six subscales (subscales derived from interviews with science teachers). The processes used to develop the items and to refine instrument are discussed. Uses for this instrument to inform professional development experiences are explored as well as implications. 相似文献
40.