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201.
The present study uses laboratory measurements to investigate the void fraction of an overtopping flow on a structure. The
overtopping flow, also called green water, was generated by the impingement of a plunging breaking wave on the structure following
the Froude similarity of an extreme hurricane wave and a simplified offshore structure. The flow is multi-phased and turbulent
with significant aeration. A fiber optic reflectometer (FOR) and bubble image velocimetry (BIV) were employed to measure the
void fraction and velocity in the flow, respectively, and to determine the water level on the deck. Mean properties of void
fraction and velocity were obtained by ensemble-averaging and time-averaging the repeated instantaneous measurements. The
temporal and spatial distributions of void fraction reveal that the flow is very highly aerated near the front of green water
and has relatively low aeration near the deck surface. The mean void fraction and velocity distributions were also depth-averaged
for simplicity and potential use in engineering applications. Using the measured data, similarity profiles for depth-averaged
void fraction, depth-averaged velocity, and water level were found. The study suggests that using only the velocity data is
insufficient if the flow momentum or the flow rate is to be determined. The accuracy of the void fraction measurements was
validated by comparing the directly measured water volume of the overtopping flow with the calculated water volume based on
the measured velocity and void fraction. 相似文献
202.
Kyukwan Zong Seung Il Shin Dong Ju Jeon Jung No Lee Eung K. Ryu 《Journal of heterocyclic chemistry》2000,37(1):75-78
3‐Aryl‐4‐methoxycarbonylisoxazoles were prepared from the reaction of a variety of substituted benzonitrile oxides with methyl 3‐(p‐nitrobenzoyloxy)acrylate in moderate to good yields. 相似文献
203.
Ashraful Alam Hidetoshi Ohta Tatsuya Yamamoto Satoshi Ogawa Ryu Sato 《Heteroatom Chemistry》2007,18(3):239-248
Naphthalene‐1‐sulfonic acid dimethylamides were treated with n‐BuLi and elemental sulfur or selenium to afford dinaphtho[1,2‐b:2′,1′‐d]thiophenes and selenophenes, respectively. This is the first example of making two C S/Se bonds and a C C bond in a single step at room temperature and also demonstrates a useful method for the synthesis of both thiophenes and selenophenes on naphthalene. In the case of the reactions of elemental selenium, diselenides were also obtained along with dinaphtho[1,2‐b:2′,1′‐d]selenophenes. The structure of dinaphtho[1,2‐b:′,1′‐d]thiophene was characterized by X‐ray crystallography as a representative molecule. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:239–248, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20291 相似文献
204.
Jin‐Woong Kim Mi‐Ok Jung Yong‐Jin Kim Jee‐Hyun Ryu Junoh Kim Ih‐Seop Chang Ok‐Sub Lee Kyung‐Do Suh 《Macromolecular rapid communications》2005,26(15):1258-1261
Summary: This communication describes an enzyme stabilization method that allows the use of enzymes irrespective of environmental factors, especially heat, while maintaining their activity for a long time. We have designed enzyme microcapsules that consist of papain enzyme cores, poly(propylene glycol) interlayers, and poly(ε‐caprolactone) walls. By confocal laser scanning microscopy measurements and the thermal stability of papain‐loaded microcapsules, it is demonstrated that the papain is surrounded by a hydrophobic polyol layer and stabilized by the exclusive volume effect. In our study, improved thermal stability can be obtained by using more hydrophobic long‐chained polyols, which is understood to be attributed to the effective formation of a hydrophobic polyol layer between the papain and the polymer wall by means of conformational anchoring in the interface.
205.
Huyeon Choi Gaeun Park Eunhye Shin Seon Woo Shin Batakrishna Jana Seongeon Jin Sangpil Kim Huaimin Wang Sang Kyu Kwak Bing Xu Ja-Hyoung Ryu 《Chemical science》2022,13(21):6197
Mitochondria are essential intracellular organelles involved in many cellular processes, especially adenosine triphosphate (ATP) production. Since cancer cells require high ATP levels for proliferation, ATP elimination can be a unique target for cancer growth inhibition. We describe a newly developed mitochondria-targeting nucleopeptide (MNP) that sequesters ATP by self-assembling with ATP inside mitochondria. MNP interacts strongly with ATP through electrostatic and hydrogen bonding interactions. MNP exhibits higher binding affinity for ATP (−637.5 kJ mol−1) than for adenosine diphosphate (ADP) (−578.2 kJ mol−1). To improve anticancer efficacy, the small-sized MNP/ADP complex formed large assemblies with ATP inside cancer cell mitochondria. ATP sequestration and formation of large assemblies of the MNP/ADP–ATP complex inside mitochondria caused physical stress by large structures and metabolic disorders in cancer cells, leading to apoptosis. This work illustrates a facile approach to developing cancer therapeutics that relies on molecular assemblies.Mitochondria-targeting nucleopeptide (MNP) can sequester ATP by self-assembling with ATP. A small nanosized MNP/ADP complex forms a large assembly with ATP. Thus, intramitochondrial co-assembly causes stress by large structures and apoptosis. 相似文献
206.
Dr. Batakrishna Jana Dr. Ajesh P. Thomas Sangpil Kim In Seong Lee Huyeon Choi Seongeon Jin Soo Ah Park Prof. Seung Kyu Min Dr. Chaekyu Kim Prof. Ja-Hyoung Ryu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(47):10695-10701
The development of photosensitizers for cancer photodynamic therapy has been challenging due to their low photostability and therapeutic inefficacy in hypoxic tumor microenvironments. To overcome these issues, we have developed a mitochondria-targeted photosensitizer consisting of an indocyanine moiety with triphenylphosphonium arms, which can self-assemble into spherical micelles directed to mitochondria. Self-assembly of the photosensitizer resulted in a higher photostability by preventing free rotation of the indoline ring of the indocyanine moiety. The mitochondria targeting capability of the photosensitizer allowed it to utilize intramitochondrial oxygen. We found that the mitochondria-targeted photosensitizer localized to mitochondria and induced apoptosis of cancer cells both normoxic and hypoxic conditions through generation of ROS. The micellar self-assemblies of the photosensitizer were further confirmed to selectively localize to tumor tissues in a xenograft tumor mouse model through passive targeting and showed efficient tumor growth inhibition. 相似文献
207.
Dr. Akira Matsumoto Bich-Ngoc Nguyen Tsubasa Honda Dr. Ryu Sakamoto Dr. Xiao Huang Prof. Dr. Shigeyoshi Sakaki Prof. Dr. Keiji Maruoka 《化学:亚洲杂志》2021,16(4):282-286
This article describes the synthetic application of ketone-derived oxaziridines as alkyl radical precursors in copper-catalyzed Carbon-Carbon bond formation reactions. Experimental and computational studies indicate a free radical mechanism, where alkyl radicals are efficiently generated via cleavage of a Carbon-Carbon bond of oxaziridines. Acyclic and unstrained cyclic oxaziridines are applicable to the present radical process, allowing for the generation of various alkyl radicals with good functional group compatibility. 相似文献
208.
S. I. Yun Ki-Dong Oh Kwon-Sang Ryu Chang-Geon Kim H. L. Park H. J. Seo Chae Kum 《Applied physics. B, Lasers and optics》1986,40(2):95-98
We have used a modified photothermal probe beam deflection system with a back pumping configuration for the measurements of the temperature-dependent thermal diffusivity of atmospheric air. The results are consistent and reasonably well agree with the literature values. The measured thermal diffusivity values are the same for the same measuring temperature regardless of the beam offsets and the deflecting surface temperatures. For the gas with known temperature-dependent thermal diffusivity, this method can be used to deduce the temperature of a gas from the measured thermal diffusivity value. 相似文献
209.
210.
The performance of Co catalysts supported on MgO at different Co loading (10%-75%) for the formation of carbon nanotubes through acetylene decomposition at 600 °C with H2/C2H2 mixture for 1 h is investigated. The yield of MWNTs increases with an increase in Co loading (up to 50%). Starting from 1 g of catalyst precursor, about 8 g of MWNTs was obtained. The XRD patterns of catalyst precursor indicate the presence of cobalt in oxidic phase that eventually transformed into the catalytically active Co nanoparticles (12-18 nm) under the influence of acetylene and was responsible for the growth of coiled-like multi-walled CNTs as revealed by SEM and HRTEM images. It is suggested that bending in coil shaped MWNTs has the potential for functionalization for its biomedical applications. 相似文献