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31.
Gurkan Hizal Umit Tunca Amitav Sanyal 《Journal of polymer science. Part A, Polymer chemistry》2011,49(19):4103-4120
Functional polymeric materials with desired properties can be designed by precise control of macromolecular architectures. Over the recent years, click reactions have enabled efficient synthesis of a variety of polymers with different topologies via efficient polymer–polymer conjugations. While the copper catalyzed Huisgen type (3+2) dipolar cycloaddition between azide and alkyne has been widely used toward this goal, the Diels–Alder (DA) reaction offers an alternative click reaction that allow efficient macromolecular conjugations, oftentimes without the need of any additional reagent or catalyst. This article highlights, with illustrative examples, the power of the DA “click” reaction to efficiently synthesize a variety of different well‐defined macromolecular constructs in a modular fashion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
32.
A gas chromatographic-mass spectrometric method was developed, validated and demonstrated by measuring the levels of nitrogen mustard hydrolysis products in the urine collected from dosed rats. The recovery values for trimethylsilyl derivatives of EDEA and MDEA are between 82-95% and 88-112%, respectively. In vivo studies performed by using three different doses (0.5 mg/kg, 1.0 mg/kg, and 2.0 mg/kg) of HN2 base of nitrogen mustard. MDEA concentrations were between 43.1-232.2 ng/mL. The limit of detection (S/N = 3) values are 2.5 ng/mL and 1.6 ng/mL for EDEA and MDEA, respectively, and the precision of the method in terms of RSD is between 5-8%. 相似文献
33.
The various phenolic compounds in conjunction with Cu(II) or Cu(I)‐N,N,N′,N″,N″‐pentamethyl diethylenetriamine (PMDETA) complexes are used to initiate atom transfer radical polymerization (ATRP) of methyl methacrylate, styrene, and methyl acrylate in the presence of a limited amount of air at temperatures in the range of 80–110 °C. Meanwhile, an effort is directed toward the elucidation of the role of phenol and derivatives in ATRP catalyzed by Cu(II)/PMDETA. The catalytic sequence involves the formation of Cu(I) by electron transfer from phenol to Cu(II); Cu(I) so formed can then react in two distinctly different ways: with organic halide to form a propagating radical or with oxygen to form copper salt in its higher oxidation state; and regeneration of Cu(I) by excess phenol. Such regeneration of Cu(I) would be expected to lead to polymerization as a result of the consumption of oxygen and phenol as well. The phenols with electron releasing groups tended to increase the conversion of the polymerization. In this respect, sodium phenoxide, a more effective additive was found, whereas p‐nitro phenol was the least effective. The obtained polymers displayed the common features of a controlled polymerization such as molecular weight control and low polydispersity index value (Mw/Mn < 1.5). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 351–359, 2004 相似文献
34.
Starovoitova V Budarz TE Wyllie GR Scheidt WR Sturhahn W Alp EE Prohofsky EW Durbin SM 《The journal of physical chemistry. B》2006,110(26):13277-13282
The normal-mode spectrum for the four-coordinated heme compound Fe(II) octaethylporphyrin, Fe(OEP), has been determined by refining force constants to the experimental Fe vibrational density of states measured with nuclear resonance vibrational spectroscopy (NRVS). Convergence of the calculated spectrum to the data was achieved by first imposing D4 symmetry on the model structure as well as the force constants, progressively including different internal coordinates of motion, then allowing the true Ci (or S2) point group symmetry of the C(i)1 Fe(OEP) crystal structure. The NRVS-refined normal modes are in good agreement with Raman and IR spectra at high frequencies. Prior density functional theory predictions for a model porphyrin are similar to the core modes computed with the best-fit force field, but significant differences between D4 and Ci modes underline the sensitivity of porphyrin Fe normal modes to structural details. Some differences between the Ci best fit and the NRVS data can be attributed to intermolecular contacts not included in the normal-mode analysis. 相似文献
35.
Merve??lkhan P?nar?Zengin Alp Emrah?Evren?KaraEmail author 《Mediterranean Journal of Mathematics》2018,15(3):136
An asymmetric norm is a positive sublinear functional p on a real vector space X satisfying \(x=\theta _X\) whenever \(p(x)=p(-x)=0\). Since the space of all lower semi-continuous linear functionals of an asymmetric normed space is not a linear space, the theory is different in the asymmetric case. The main purpose of this study is to define bounded and continuous linear operators acting between asymmetric cone normed spaces. After examining the differences with symmetric case, we give some results related to Baire’s characterization of completeness in asymmetric cone normed spaces. 相似文献
36.
The concept of efficiency in data envelopment analysis (DEA) is defined as weighted sum of outputs/weighted sum of inputs. In order to calculate the maximum efficiency score, each decision making unit (DMU)’s inputs and outputs are assigned to different weights. Hence, the classical DEA allows the weight flexibility. Therefore, even if they are important, the inputs or outputs of some DMUs can be assigned zero (0) weights. Thus, these inputs or outputs are neglected in the evaluation. Also, some DMUs may be defined as efficient even if they are inefficient. This situation leads to unrealistic results. Also to eliminate the problem of weight flexibility, weight restrictions are made in DEA. In our study, we proposed a new model which has not been published in the literature. We describe it as the restricted data envelopment analysis ((ARIII(COR))) model with correlation coefficients. The aim for developing this new model, is to take into account the relations between variables using correlation coefficients. Also, these relations were added as constraints to the CCR and BCC models. For this purpose, the correlation coefficients were used in the restrictions of input–output each one alone and their combination together. Inputs and outputs are related to the degree of correlation between each other in the production. Previous studies did not take into account the relationship between inputs/outputs variables. So, only with expert opinions or an objective method, weight restrictions have been made. In our study, the weights for input and output variables were determined, according to the correlations between input and output variables. The proposed new method is different from other methods in the literature, because the efficiency scores were calculated at the level of correlations between the input and/or output variables. 相似文献
37.
Lena Scherthan Sebastian F. M. Schmidt Hendrik Auerbach Tim Hochdrffer Juliusz A. Wolny Wenli Bi Jiyong Zhao Michael Y. Hu Tom Toellner E. Ercan Alp Dennis E. Brown Christopher E. Anson Annie K. Powell Volker Schünemann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3482-3487
Time‐domain synchrotron Mössbauer spectroscopy (SMS) based on the Mössbauer effect of 161Dy has been used to investigate the magnetic properties of a DyIII‐based single‐molecule magnet (SMM). The magnetic hyperfine field of [Dy(Cy3PO)2(H2O)5]Br3?2 (Cy3PO)?2 H2O?2 EtOH is with B0=582.3(5) T significantly larger than that of the free‐ion DyIII with a 6H15/2 ground state. This difference is attributed to the influence of the coordinating ligands on the Fermi contact interaction between the s and 4f electrons of the DyIII ion. This study demonstrates that 161Dy SMS is an effective local probe of the influence of the coordinating ligands on the magnetic structure of Dy‐containing compounds. 相似文献
38.
Dağlı Özge Köse Dursun Ali İçten Okan Avcı Gülçin Alp Şahin Onur 《Journal of Thermal Analysis and Calorimetry》2019,136(4):1467-1480
Journal of Thermal Analysis and Calorimetry - The coumarilate (coum?) and 1,10-phenanthroline (phen) mixed ligand complexes of Co(II) (1), Ni(II) (2) Cu(II) (3) and Zn(II) (4) were... 相似文献
39.
Liu D Chu XQ Lagi M Zhang Y Fratini E Baglioni P Alatas A Said A Alp E Chen SH 《Physical review letters》2008,101(13):135501
Molecular dynamics simulations and neutron scattering experiments have shown that many hydrated globular proteins exhibit a universal dynamic transition at TD = 220 K, below which the biological activity of a protein sharply diminishes. We studied the phononlike low-energy excitations of two structurally very different proteins, lysozyme and bovine serum albumin, using inelastic x-ray scattering above and below TD. We found that the excitation energies of the high-Q phonons show a marked softening above TD. This suggests that the large amplitude motions of wavelengths corresponding to this specific Q range are intimately correlated with the increase of biological activities of the proteins. 相似文献
40.
Alp Arslan Kiraç 《Letters in Mathematical Physics》2008,83(2):149-161
Consider the Mathieu–Hill operator
in , where . We obtain the precise asymptotic formulas for the widths γ
k
of the instability intervals of L. The formula states the isolated terms of arbitrary number in the asymptotics of the sequence γ
k
for large k and verifies the results of Harrell (Am J Math suppl:139–150, 1981) and Avron and Simon (Ann Phys 134:76–84, 1981).
相似文献