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71.
Conformational properties of isotactic poly(2-hydroxyethyl methacrylate) (PHEMA) have been studied by viscometry in various electrolytic solutions. The intrinsic viscosity of isotactic PHEMA at 0.01M salt solution increases with decreasing the B coefficient in Jones—Dole's equation. In respective to water structures, a polymer chain is more expanded in the salt solution including water structure breaker ions. As the concentration of ions increases, the interactions between polymer segments and ions make a major contribution to conformational changes of isotactic PHEMA. Depending on the kind of ions, a salting-in or out effect is observed at higher concentrations than 0.1M salt solution. We observed that the denaturing effects of various anions in isotactic PHEMA salt solutions are as follows; SO42- < F? < I? NO3? < SCN-. This order is similar to the Hofmeister series. To investigate the influences of denaturing agents on solvent structures, we also compared the guanidine hydrochloride effect with the tetrabutylammonium chloride effect in isotactic PHEMA solution. 相似文献
72.
The nature of the network structure and the evolution of structural change in shear flow were investigated for metal particle dispersions in terms of fractal aggregation of colloidal particles. Polymer-stabilized metal particle inks were prepared via a polyvinyl chloride coating dispersed in solvent. The fractal dimension of 1.74 was calculated with the scaling model based on the power law relationship between the elastic modulus and volume fraction. This scaling behavior can be explained by considering the deformable network structure of soft materials. While the elastic property of the floc was dominant, the limit of linearity was found at the inter-floc link, which is relatively weak and brittle. The steady shear results reveal two mechanisms that contribute to the breakdown of the microstructure in metal particle inks at increasing shear rate. Scaling of steady shear viscosity shows that these mechanisms are related to both inter-floc interactions and the elasticity of the floc itself. Further, these results suggest that individual flocs deform with weak inter-floc interactions and rupture into smaller flocs or aggregates at high shear stress, which is associated with the increased shear rate. 相似文献
73.
A study is made of the coupling between chemical reaction and diffusion in a dense fluid. Our analysis utilizes the projection operator formalism and a generalized Langevin equation that is based on irreversible, phenomenological equations of motion instead of conventional Hamiltonian mechanics. It also is shown that this same non-Hamiltonian theory provides a simple way of deriving Kawasaki's mode-mode coupling theory of diffusion.This research was supported by a grant from the National Science Foundation. 相似文献
74.
Undoped Layered Perovskite Oxynitride Li2LaTa2O6N for Photocatalytic CO2 Reduction with Visible Light 下载免费PDF全文
Takayoshi Oshima Tom Ichibha Ken Sinkou Qin Kanemichi Muraoka Dr. Junie Jhon M. Vequizo Keisuke Hibino Ryo Kuriki Dr. Shunsuke Yamashita Prof. Dr. Kenta Hongo Dr. Tomoki Uchiyama Prof. Dr. Kotaro Fujii Dr. Daling Lu Prof. Dr. Ryo Maezono Prof. Dr. Akira Yamakata Prof. Dr. Hideki Kato Dr. Koji Kimoto Prof. Dr. Masatomo Yashima Prof. Dr. Yoshiharu Uchimoto Prof. Dr. Masato Kakihana Prof. Dr. Osamu Ishitani Prof. Dr. Hiroshi Kageyama Prof. Dr. Kazuhiko Maeda 《Angewandte Chemie (International ed. in English)》2018,57(27):8154-8158
Oxynitrides are promising visible‐light‐responsive photocatalysts, but their structures are almost confined with three‐dimensional (3D) structures such as perovskites. A phase‐pure Li2LaTa2O6N with a layered perovskite structure was successfully prepared by thermal ammonolysis of a lithium‐rich oxide precursor. Li2LaTa2O6N exhibited high crystallinity and visible‐light absorption up to 500 nm. As opposed to well‐known 3D oxynitride perovskites, Li2LaTa2O6N supported by a binuclear RuII complex was capable of stably and selectively converting CO2 into formate under visible light (λ>400 nm). Transient absorption spectroscopy indicated that, as compared to 3D oxynitrides, Li2LaTa2O6N possesses a lower density of mid‐gap states that work as recombination centers of photogenerated electron/hole pairs, but a higher density of reactive electrons, which is responsible for the higher photocatalytic performance of this layered oxynitride. 相似文献
75.
V. P. Voloshin Yu. I. Naberukhin N. N. Medvedev Mu Shik Jhon 《Journal of Structural Chemistry》1995,36(3):432-438
Mutual arrangement of atomic cells (defined as Voronoi polyhedra) in a large volume is studied by percolation analysis on
the Delaunay network in terms of molecular dynamic models of Lennard-Jones liquids, crystals, and amorphous solids. Characteristics
of percolative clusters as well as percolation thresholds proved to be almost the same for all the phases. From this it is
inferred that the liquid-glass phase transition is not due to percolation over regions with large free volume.
Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences. Korean Institute of Advanced
Science and Technology. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 3, pp. 473–480, May–June, 1995
Translated by L. Smolina 相似文献
76.
77.
Jhon YH Shim JG Kim JH Lee JH Jang KR Kim J 《The journal of physical chemistry. A》2010,114(49):12907-12913
Both nucleophilicities and accessibilities of three alkanolamines [monoethanolamine (MEA), (2-(methylamino)ethanol (MAE), and 2-amino-2-methyl-1-propanol (AMP)] were calculated to predict their reactivities with CO(2). After DFT geometry-optimization calculations, the global, group, and atomic nucleophilicities of each amine were obtained using MP2 quantum mechanical calculations. Only global nucleophilicity matched an experimental pK(a) order (MAE > AMP > MEA). However, it failed to predict the slow rate of the sterically hindered AMP and the order of rate constants, MAE > MEA > AMP. The accessibilities of amines to CO(2) have been calculated by MD simulations by monitoring collisions at the reaction centers: N atoms in amines and C in CO(2). The accessibility results indicate that global nucleophilicity needs quantitative correction for steric effects to predict better reactivities of amines with CO(2). 相似文献
78.
Pil Seung Chung Dae Sup So Lorenz T. Biegler Myung S. Jhon 《Journal of nanoparticle research》2012,14(8):1-20
Developments in nanotechnology have led to innovative progress and converging technologies in engineering and science. These demand novel methodologies that enable efficient communications from the nanoscale all the way to decision-making criteria for actual production systems. In this paper, we discuss the convergence of nanotechnology and novel multi-scale modeling paradigms by using the fuel cell system as a benchmark example. This approach includes complex multi-phenomena at different time and length scales along with the introduction of an optimization framework for application-driven nanotechnology research trends. The modeling paradigm introduced here covers the novel holistic integration from atomistic/molecular phenomena to meso/continuum scales. System optimization is also discussed with respect to the reduced order parameters for a coarse-graining procedure in multi-scale model integration as well as system design. The development of a hierarchical multi-scale paradigm consolidates the theoretical analysis and enables large-scale decision-making of process level design, based on first-principles, and therefore promotes the convergence of nanotechnology to sustainable energy technologies. 相似文献
79.
Choi HJ Lee IS Sung JH Park BJ Jhon MS 《Journal of colloid and interface science》2006,295(1):291-293
The comments on the recent results on electrorheological (ER) property of rare earth modified amorphous barium strontium titanate gel based ER fluid are given via analysis of its dynamic yield stress data as a function of applied electric field strengths. Using our previously reported universal yield stress equation, we obtained the critical electric field strength and collapsed their data onto a single curve. 相似文献
80.
YoungKwan Park SangBeom Choi Hyunuk Kim Kimoon Kim Byoung‐Ho Won Kihang Choi Jung‐Sik Choi Wha‐Seung Ahn Nayoun Won Sungjee Kim DongHyun Jung Seung‐Hoon Choi Ghyung‐Hwa Kim Sun‐Shin Cha YoungHo Jhon JinKuk Yang Jaheon Kim 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2007,119(43):8378-8381