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101.
Jeon JY Lee PJ Hong JY Cabrera D 《The Journal of the Acoustical Society of America》2011,130(6):3761-3770
The aim of this study is to characterize urban spaces, which combine landscape, acoustics, and lighting, and to investigate people's perceptions of urban soundscapes through quantitative and qualitative analyses. A general questionnaire survey and soundwalk were performed to investigate soundscape perception in urban spaces. Non-auditory factors (visual image, day lighting, and olfactory perceptions), as well as acoustic comfort, were selected as the main contexts that affect soundscape perception, and context preferences and overall impressions were evaluated using an 11-point numerical scale. For qualitative analysis, a semantic differential test was performed in the form of a social survey, and subjects were also asked to describe their impressions during a soundwalk. The results showed that urban soundscapes can be characterized by soundmarks, and soundscape perceptions are dominated by acoustic comfort, visual images, and day lighting, whereas reverberance in urban spaces does not yield consistent preference judgments. It is posited that the subjective evaluation of reverberance can be replaced by physical measurements. The categories extracted from the qualitative analysis revealed that spatial impressions such as openness and density emerged as some of the contexts of soundscape perception. 相似文献
102.
Bahni Ray P. Dinesh Sankar Reddy Dipankar Bandyopadhyay Sang Woo Joo Ashutosh Sharma Shizhi Qian Gautam Biswas 《Theoretical and Computational Fluid Dynamics》2012,26(1-4):311-318
Instability of a thin electrolyte film undergoing a direct current electroosmotic flow has been investigated. The film with a compliant electrolyte–air interface is flowing over a rigid charged substrate. Unlike previous studies, inclusion of the Maxwell stresses in the formulation shows the presence of a new finite wavenumber shear-flow mode of instability, alongside the more frequently observed long-wave interfacial mode. The shear mode is found to be the dominant mode of instability when the electrolyte–solid and electrolyte–air interfaces are of opposite charge or of same charge but have very large zeta-potential at the electrolyte–air interface. The conditions for mode-switch (interfacial to shear) and the direction of the travelling waves are discussed through stability diagrams. Interestingly, the analysis shows that when the interfaces are of nearly same zeta potential, the ‘free’ electrolyte–air interface behaves more like a ‘stationary’ wall because of the ion transport in the reverse direction of the flow. 相似文献
103.
104.
HoSeok Park Prof. Dr. Young Mee Jung Prof. Dr. Seong Ho Yang Dr. Weonho Shin Jung Ku Kang Prof. Dr. Hoon Sik Kim Prof. Dr. Hyun Joo Lee Dr. Won Hi Hong Prof. Dr. 《Chemphyschem》2010,11(8):1711-1717
Geometric and conformational changes of zwitter‐type ionic liquids (ZILs) due to hydrogen‐bonding interactions with water molecules are investigated by density functional theory (DFT), two‐dimensional IR correlation spectroscopy (2D IR COS), and pulsed‐gradient spin‐echo NMR (PGSE NMR). Simulation results indicate that molecular structures in the optimized states are strongly influenced by hydrogen bonding of water molecules with the sulfonate group or imidazolium and pyrrolidinium rings of 3‐(1‐methyl‐3‐imidazolio)propanesulfonate ( 1 ) and 3‐(1‐methyl‐1‐pyrrolidinio)propanesulfonate ( 2 ), respectively. Concentration‐dependent 2D IR COS reveals kinetic conformational changes of the two ZIL–H2O systems attributable to intermolecular interactions, as well as the interactions of sulfonate groups and imidazolium or pyrrolidinium rings with water molecules. The dramatic changes in the 1H self‐diffusion coefficients elucidate the formation of proton‐conduction pathways consisting of ZIL networks. In ZIL domains, protons are transferred by a Grotthuss‐type mechanism through formation, breaking, and restructuring of bonds between ZILs and H2O, leading to an energetically favorable state. The simulation and experimental investigations delineated herein provide a perspective to understanding the interactions with water from an academic point of view as well as to designing ILs with desired properties from the viewpoint of applications. 相似文献
105.
By treatment of tris(azidomethyl)amine with dry hydrogen halide, azidochloromethane and azidobromomethane were prepared. The former product, which is more stable than the latter, was isolated as a colorless liquid. The desired azidohalomethanes are intermediates in the nucleophilic substitution of dihalomethanes to generate diazidomethane but could not be detected in this transformation. 相似文献
106.
We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator 相似文献
107.
Bun‐Joo Kim Yong‐Min Lee Eun Hee Kim Sung Kwon Kang Sung‐Nak Choi 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):m361-m362
In the title complex, [Cu(N3)2(C15H26N2)], the Cu atom is surrounded by the two N atoms of the chelating (?)‐α‐isosparteine ligand and another two N atoms from the two azide anions, forming a distorted CuN4 tetrahedron. The two azide anions are terminally bound to the CuII atom, and the dihedral angle between the Nsparteine—Cu—Nsparteine and Nazide—Cu—Nazide planes is 50.0 (2)°. 相似文献
108.
Lee KI Joo SJ Lee JH Rhie K Kim TS Lee WY Shin KH Lee BC LeClair P Lee JS Park JH 《Physical review letters》2007,98(10):107202
Tunneling magnetoresistance was found to be suppressed with decreasing temperature for magnetic tunnel junctions (MTJs) oxidized under high plasma power. A strong temperature dependence of the junction resistance was observed, along with zero-bias anomalies of dynamic resistance at low temperatures. Resistance shows a logarithmic dependence on temperature, and resistance versus temperature exhibits a scaling behavior. Our experimental data can be explained in a consistent way by the Kondo effect in the MTJs with the Kondo temperature TK=20-30 K. 相似文献
109.
Navasardyan T Adams GS Ahmidouch A Angelescu T Arrington J Asaturyan R Baker OK Benmouna N Bertoncini C Blok HP Boeglin WU Bosted PE Breuer H Christy ME Connell SH Cui Y Dalton MM Danagoulian S Day D Dodario T Dunne JA Dutta D El Khayari N Ent R Fenker HC Frolov VV Gan L Gaskell D Hafidi K Hinton W Holt RJ Horn T Huber GM Hungerford E Jiang X Jones M Joo K Kalantarians N Kelly JJ Keppel CE Kubarovski V Li Y Liang Y Malace S Markowitz P McGrath E McKee P Meekins DG Mkrtchyan H Moziak B 《Physical review letters》2007,98(2):022001
A large data set of charged-pion (pi+/-) electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-->pion production mechanisms. 相似文献
110.
Anchoring Mechanism of ZnO Nanoparticles on Graphitic Carbon Nanofiber Surfaces through a Modified Co‐Precipitation Method to Improve Interfacial Contact and Photocatalytic Performance 下载免费PDF全文
Dr. Gowra Raghupathy Dillip Dr. Arghya Narayan Banerjee Dr. Veettikunnu Chandran Anitha Dr. Sang Woo Joo Dr. Bong Ki Min Dr. Sandesh Y. Sawant Dr. Moo Hwan Cho 《Chemphyschem》2015,16(15):3214-3232
A facile three‐step co‐precipitation method is developed to synthesize graphitic carbon nanofibers (CNFs) decorated with ZnO nanoparticles (NPs). By interchanging intermediate steps of the reaction processes, two kinds of nanohybrids are fabricated with stark morphological and physicochemical differences. The morphologies differ because of the different chemical environments of the NP/nanocluster formation. The hybrid with larger and non‐uniform ZnO nanocluster size is formed in liquid phase and resulted in considerable interfacial defects that deteriorate the charge‐transfer properties. The hybrid with smaller and uniform ZnO NPs was formed in a dry solid phase and produced near‐defect‐free interfaces, leading to efficient charge transfer for superior photocatalytic performance. The results broaden the understanding of the anchoring/bonding mechanism in ZnO/CNF hybrid formation and may facilitate further development of more effective exfoliation strategies for the preparation of high‐performance composites/hybrids. 相似文献