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151.
Marko Zupan Peter Krajnc Stojan Stavber 《Journal of polymer science. Part A, Polymer chemistry》1998,36(11):1699-1706
Crosslinked copoly(styrene-p-nitrophenylacrylates), containing 2% (1) or 4% DVB (2) were converted with various diaminoalkanes (1,2-diaminoethane 3a, 1,4-diaminobutane 3b, 1,8-diaminooctane 3c) to amides. The degree of additional crosslinking depended on the chain length of the diaminoalkane, the molar ratio of ester function in 1 or 2 to diaminoalkane, solvent polarity (dimethylformamide, chloroform, toluene), while reaction temperature (50 or 100°C) had only a minor effect. 2 was also converted with various amines bearing additional functional groups (ethanolamine, 3-amino-1-propanol, 4-aminomethylpyridine, 2-(2-aminoethylamino)-ethanol, 2-(2-aminoethoxy)-ethanol, 6-aminocaproic acid, N-propylaminomorpholine, 3-N,N-diethylamino-1-propylamine) to the corresponding amides. The swelling ability of the resins depended on the crosslinking of the starting copoly(styrene-p-nitrophenylacrylate) (1, 2), the structure of the amide, the degree of additional crosslinking, and solvent polarity (chloroform, dimethylformamide, methanol, toluene). The accessibility of nitrogen atoms in the polymer matrix was examined by EtX functionalization of the 3-N,N-diethylamino-1-propylamine derivative (10) and 4-aminomethylpyridine derivative (13), and more than 85% functionalization was found. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1699–1706, 1998 相似文献
152.
153.
Henrik Ebel Marko K. Matikainen Vesa-Ville Hurskainen Aki Mikkola 《Nonlinear dynamics》2017,88(2):1075-1091
This study thoroughly examines various higher-order three and four-node beam elements for use in the absolute nodal coordinate formulation (ANCF). The paper carefully investigates which potential benefits and drawbacks the utilization of higher-order ANCF beam elements without in-slope vectors has in the case of the usage of full three-dimensional elasticity. When the elastic forces for shear-deformable ANCF beam elements are calculated using full three-dimensional elasticity—especially in the form of the St. Venant–Kirchhoff material law—Poisson locking severely deteriorates the accuracy of the numeric results. As shown in this paper, an existing approach to preventing this locking phenomenon for three-node beam elements can still produce unsatisfying results in load cases involving bidirectional bending. The results of this study show that enriching the polynomial basis used to approximate the beam kinematics provides a natural solution to this issue. As will be seen, these findings for three-node elements can also be extended to four-node elements. When using a sufficient approximation order in transverse directions, satisfying accuracy can be achieved both in conventional one-dimensional bending and in the above-mentioned bidirectional load case. 相似文献
154.
Nonequilibrium model for steady state simulation of catalytic distillation is presented. Mathematical model takes into account
both mass and heat transfers across the gas liquid interface and through the liquid-solid (catalyst) interface. Equations
describing the mentioned phenomena are based on the effective diffusivity approach. The resulting system of nonlinear algebraic
equations was implemented in the FORTRAN programming language and solved by the BUNLSI (Ferraris & Tronconi, 1986) solver.
The described model was verified using the experimental data obtained from a continuous distillation column equipped with
catalytic packing. As an experimental model system, synthesis of propyl propionate from propan-1-ol and propionic acid was
chosen. Comparison of experimental and simulation data is presented, and appropriateness of the developed model for other
types of catalytic distillation processes is discussed.
Presented at the 35th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 26–30 May
2008. 相似文献
155.
Marko P. Sušnik Michael Schnürch Marko D. Mihovilovic Kurt Mereiter Peter Stanetty 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):423-430
Abstract A short and efficient sequence for the synthesis of a series of 4-(2-amino-5-thiazolyl)-pyrimidine-2-amines was developed.
1-Phenyl-2-(6-pyrimidinyl)-ethanones, obtained via Weinreb’s methodology, were used in a Hantzsch thiazole cyclization reaction,
followed by introduction of the aniline moieties via nucleophilic substitution.
Graphical abstract
相似文献
156.
157.
Ion Gutiérrez-Aguirre Marko Banjac Andrej Steyer Mateja Poljšak-Prijatelj Matjaž Peterka Aleš Štrancar Maja Ravnikar 《Journal of chromatography. A》2009,1216(13):2700-2704
Rotaviruses are the leading cause of diarrhoea in infants around the globe and, under certain conditions they can be present in drinking water sources and systems. Ingestion of 10–100 viral particles is enough to cause disease, emphasizing the need for sensitive diagnostic methods. In this study we have optimized the concentration of rotavirus particles using methacrylate monolithic chromatographic supports. Different surface chemistries and mobile phases were tested. A strong anion exchanger and phosphate buffer (pH 7) resulted in the highest recoveries after elution of the bound virus with 1 M NaCl. Using this approach, rotavirus particles spiked in 1 l volumes of tap or river water were efficiently concentrated. The developed concentration method in combination with a real time quantitative polymerase chain reaction assay detected rotavirus concentrations as low as 100 rotavirus particles/ml. 相似文献
158.
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159.
160.
Starting from the Strassen method for rapid matrix multiplication and inversion as well as from the recursive Cholesky factorization algorithm, we introduced a completely block recursive algorithm for generalized Cholesky factorization of a given symmetric, positive semi-definite matrix A∈Rn×n. We used the Strassen method for matrix inversion together with the recursive generalized Cholesky factorization method, and established an algorithm for computing generalized {2,3} and {2,4} inverses. Introduced algorithms are not harder than the matrix–matrix multiplication. 相似文献