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51.
Yu‐Yang Liu Xiao‐Dong Fan YA‐Bing Zhao 《Journal of polymer science. Part A, Polymer chemistry》2005,43(16):3516-3524
A novel linear poly(N‐isopropylacrylamide) (PNIPA) with β‐cylodextrin (β‐CD) moiety (PNIPA‐β‐CD) was synthesized by the conjugation of β‐CD carrying amino groups (EDA‐β‐CD) onto PNIPA with epoxy groups (P(NIPA‐co‐GMA), Mn = 3.86 × 104), and the related reaction conditions are investigated. PNIPA‐β‐CD was characterized by means of IR, NMR and UV spectroscopes, element analysis, and differential scanning calorimetry (DSC). The number‐average molecular weight (Mn) and the β‐CD content of the obtained PNIPA‐β‐CD are 4.87 × 104 and 18.8 wt %, respectively. PNIPA‐β‐CD can not only respond to temperature stimuli but also include guest molecules. Lower critical solution temperature (LCST) of aqueous PNIPA‐β‐CD solution is similar to that of PNIPA. The association constant (Ka) for PNIPA‐β‐CD with methyl orange (MO) is 2.4 × 103 L mol?1 at pH 1.4, which is comparable to that of EDA‐β‐CD (Ka = 2.9 × 103 L mol?1). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3516–3524, 2005 相似文献
52.
将纳米金(NG)电沉积在有序介孔碳(OMC)修饰玻碳电极表面,并将L-半胱氨酸(L-Cys)自组装至OM C/NG修饰电极表面,制备了OM C/NG/L-Cys修饰电极。采用透射电子显微镜考察了OM C的结构,扫描电子显微镜研究了OMC/NG/L-Cys修饰电极的表面形貌。考察了Cu2+在该修饰电极上的电化学行为,优化了Cu2+的测定条件。在最优条件下,溶出峰峰电流与Cu2+浓度在0.05~6.0μmol/L范围内呈良好线性关系,检出限为0.03μmol/L(S/N=3)。方法用于河水样品分析,其加标回收率在92.7%~101.6%之间。 相似文献
53.
54.
The X-band ( x ; 9.4 v GHz) electron spin resonance (ESR) spectra of the un-doped isotopically enriched lithium tetraborate (LTB) Li 2 B 4 O 7 single crystals, irradiated by thermal neutrons (fluences | n =2.74 ‐ 10 15 1 1.79 v ‐ 10 18 v cm m 2 ) were investigated at 300 and 77 v K. The LTB crystals of high chemical purity and optical quality with different isotope compositions ( 6 Li 2 10 B 4 O 7 , 6 Li 2 11 B 4 O 7 , 7 Li 2 10 B 4 O 7 and 7 Li 2 11 B 4 O 7 ) were grown by Czochralski technique. The thermal neutrons (the total quantity >90%) with fluence near 10 18 v cm m 2 induce at least 4 different types of stable paramagnetic centers in the Li and B isotopically enriched LTB crystals. The ESR spectra, electron structure and efficiency of generation for centers, induced by thermal neutrons, essentially depend on neutron fluence and isotope composition of the LTB crystals. The local symmetry and the spin Hamiltonian parameters of the observed paramagnetic centers were determined and their electron structure were established. The possible models and formation mechanism of the radiation defects, induced by thermal neutrons in the LTB lattice, are proposed. 相似文献
55.
Statistical distributions of the frequencies of OH vibrations calculated from the experimental Raman spectra of HOD molecules over the temperature range of 10–200 C using the recently developed deconvolution technique have been analysed in the framework of fluctuation theory of hydrogen bonding. Two temperature independent functions that are the basis of the Zhukovsky theory for describing the temperature transformation of frequency distribution functions of OH vibrations in a statistical ensemble of O—H…O bonds were established and analytically approximated. This made it possible to reconstruct the entire set of initial spectra and to extrapolate their forms to a wider temperature range. These results support the continuum model of liquid water structure. 相似文献
56.
57.
Güneri Akovali 《Journal of Polymer Science.Polymer Physics》1967,5(5):875-889
An extension of the results of a previous to higher molecular weights is made. The viscoelastic parameters ηt, Je, τm, and Em are found experimentally through stress relaxation tests. The predictions of the Rouse-Bueche (RB) theory and its modified Ferry, Landel, Williams (FLW) form concerning the molecular weight dependencies of these perameters are compared with the data. It is found that the RB and FLW predictions are not rigorously obeyed. 相似文献
58.
59.
N. YA. Turova E. P. Turevskaya V. G. Kessler M. I. Yanovskaya 《Journal of Sol-Gel Science and Technology》1994,2(1-3):17-23
X-ray structural analysis of crystalline alkoxides in many cases reveals that along with OR-groups their molecules also contain oxo-ligands. The following possible reactions leading to formation of oxoalkoxides have been discussed: hydrolysis, pyrolysis (frequently uncontrollable), ether elimination, oxidation of OR-groups (which exist in solutions of alkali, alkaline-earth and rare earth elements), or alkoxides of the lower oxidation states (which are formed by reduction of M(OR)
n
on cathode during electrolysis or by hydrogen in statu nascendi). Oligomeric oxoalkoxides differ from the polymeric alkoxides M(OR)
n
in considerably higher solubility and reactivity. The most important role of oxoalkoxides in the processes of formation of oxides has been demonstrated using as an example preparation of BaTiO3 from alkoxides. 相似文献
60.
Fin materials can be observed in a variety of engineering applications. They are used to ease the dissipation of heat from a heated wall to the surrounding environment. In this work, we consider a nonlinear fin problem with temperature-dependent thermal conductivity and heat transfer coefficient. The equation(s) under study are highly nonlinear. Both the thermal conductivity and the heat transfer coefficient are given as arbitrary functions of temperature. Firstly, we consider the Lie group analysis for different cases of thermal conductivity and the heat transfer coefficients. These classifications are obtained from the Lie group analysis. Then, the first integrals of the nonlinear straight fin problem are constructed by three methods, namely, Noether’s classical method, partial Noether approach and Ibragimov’s nonlocal conservation method. Some exact analytical solutions are also constructed. The obtained result is also compared with the result obtained by other methods. 相似文献