Young Hwan Kim

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTWater soluble hyperbranched polyphenylene: "a unimolecular micelle?"Young H. Kim and Owen W. WebsterCite this: J. Am. Chem. Soc. 1990, 112, 11, 4592–4593Publication Date (Print):May 1, 1990Publication History Published online1 May 2002Published inissue 1 May 1990https://pubs.acs.org/doi/10.1021/ja00167a094https://doi.org/10.1021/ja00167a094research-articleACS PublicationsRequest reuse permissionsArticle Views2752Altmetric-Citations657LEARN ABOUT THESE

Well‐defined, large dendritic molecules with branches at almost every repeat unit have recently been shown to form ordered structures such as gels and liquid‐crystalline phases. The highly branched Highly Branched Polymers polyamide shown in the Figure forms, for example, a nematic phase as a 40 wt‐% solution in amides, and as a 60 wt‐% solution forms a gel static conditions but becomes fluid under shear stress. magnified image

Abstract This study presents reflectivity images of the northeast (NE) Japan subduction zone continuous across the ocean and land. As nearly half of its forearc region is under the ocean, data from ocean bottom seismometers (OBSs) must be utilized to fully image the region by passive seismic analysis. The use of OBS data has been a challenge due to inherent characters of the ocean bottom observations: high noise level and effects of seafloor sediment. Now, decent imaging is possible in NE Japan

The amplitude of a back-wall echo depends on the reflection coefficient of the interface between a transducer and a test material when using contact pulse-echo ultrasonic testing. A couplant is used to transmit ultrasonic energy across the interface, but has an influence on the amplitude of the pulse-echo signal. To investigate the couplant effect on pulse-echo ultrasonic testing, back-wall echoes are measured by using various couplants made of water and glycerine in a carbon and austenitic stai

A novel method is proposed for the simultaneous measurement of longitudinal and transverse wave velocities and the thickness of isotropic solid plates from access on only one side. Line contact transducers were placed on the same side of the specimen, and waveforms were acquired at various distances between the transducers. Longitudinal wave velocity and the thickness of the specimen can be simultaneously determined from the relationship between the transit time of the longitudinal wave mode and

Abstract This study presents an approach to better characterize the P‐wave and S‐wave velocity structure of the seafloor sediment layer using ocean bottom seismometers. The presence of low‐velocity seafloor sediment layers influences the observed seismic record at the seafloor over a broad frequency range, such that detailed knowledge of this sediment structure is essential to predict its effect on teleseismic records. We use the radial component of teleseismic P waves and autocorrelation functi

The effects of hydrophobic agents on aqueous foam stability were studied in the presence of an antifoamer, based on the destabilization mechanisms of aqueous foam. The stability of the foam film was dependent on both film rheology and structural modification by the hydrophobic agents, tertiary butyl phosphate (TBP) and lecithin. The hydrophobic agents reduced the elasticity of the foam film and the surface activity of the surfactant that stabilize the foam film. TBP effectively accelerated the f

The aim of this study is to present learning activities using Padlet to facilitate communication and exchange of opinions among learners in large-scale, remote liberal arts classes, and to examine learners' perceptions of and responses to the use of Padlet as a learning tool. Communication and opinion-sharing activities need to be managed efficiently to minimize the difference in quantity and quality of such activities in remote classes compared to face-to-face. Padlet was actively used for lear

Abstract This study presents a new velocity model for the Salt Lake basin (SLB) in Utah, determined using data from permanent and temporary seismic stations located on top of the basin in the Salt Lake Valley (SLV) and nearby. A three‐dimensional (3D) velocity model for the SLB is needed for accurate predictions of future damaging earthquake ground shaking in the heavily urbanized SLV, including Salt Lake City. The SLB part of the Wasatch Front community velocity model (WFCVM) currently serves t