2,330 research outputs found
Dynamic characteristics of ER fluid-filled composite plate using multielectrode configuration
No full textIn this research, a smart structure with multielectrode configuration has been proposed, which contains electrorheological (ER) fluid. Multielectrode configuration gives the structure a capability to change its modal characteristics effectively. The proposed configuration also provides the effective vibration control performance with reduced power consumption in the smart structures. A finite element model has been developed for the analysis of a smart composite plate under fully and partially applied electric fields. The numerical results of the composite plate with ER fluid have been compared with the experimental results. The performance and energy consumption of the control system have been experimentally investigated for various applied areas of electric field by applying a semi-active control law to the vibrating composite plate.This study has been supported by a grant from the National Research Program of the
Ministry of Science and Technology, Korea. The authors gratefully acknowledge this
support
Brain activation of reading Korean words and recognizing pictures by korean native speakers: A functional magnetic resonance imaging study
No full textEven though the Korean words are characterized as phonemes like other alphabetic languages, their shape resembles much more morphemes like Chinese characters. The main purpose of the study is to explore neural mechanisms of reading Korean words and recognizing pictures by Korean native speakers using functional magnetic resonance imaging technique. In the experimental results, the authors Could see commonly activated areas in occipito-temporal region bilaterally, whereas frontal and temporal region was activated only while reading Korean words. Left middle frontal activation of Korean words was regarded to be involved in the phonological and semantic processing. Right anterior cingulate (BA 32) activation seems to be related with language and sound organization and superior temporal (BA 29) activation might be involved in the processing of phonological system to which tonal information is attached. Right medial frontal (BA 8) activation was reported in the results. The authors suggest the activation of this area is related with nonverbal visual higher order control or visuospatial analysis of Korean words in their experimental tasks
Vibration and damping analysis of laminated plates with fully and partially covered damping layers
No full textThe finite element method based on layerwise displacement theory is applied to the dynamic problem of anisotropic laminated plates treated with a constrained viscoelastic layer. Damping value of each mode is obtained by using the modal sh ain energy method and the modal approach to complex stiffness. To suppress the undesired vibrations of the wing skin in aircraft structures, the surface of the composite plates can be either fully or partially coated with a constrained viscoelastic layer. Through several numerical examples, the effects of stacking sequences, side-to-thickness ratios of the plate, locations of partially covered damping layers, and the thicknesses of the viscoelastic layers on vibration and damping characteristics are investigated
Neural mechanisms of Korean word reading: a functional magnetic resonance imaging study
No full textThe use of functional magnetic resonance imaging permits the collection of brain activation patterns when native Korean speakers (12 persons as subjects) read Korean words and Chinese characters. The Korean language uses both alphabetic Korean words and logographic Chinese characters in its writing system. Our experimental results show that the activation patterns obtained for reading Chinese characters by Korean native speakers involve neural mechanisms that are similar to Chinese native speakers; i.e. strong left-lateralized middle frontal cortex activation. For the case of Korean word reading, the activation pattern in the bilateral fusiform gyrus, left middle frontal gyrus, left superior temporal gyrus, right mid temporal gyrus, precentral gyrus, and insula was observed. This suggests that the activation pattern for Korean word reading appears to corroborate with that of alphabetic words at the general level. A further noteworthy finding of our study is the strong activation of the posterior part of the right dorsolateral prefrontal cortex (BA 8). The right hemispheric BA 8 belongs to the visual higher order control area and we propose that this area should be responsible for processing of visuospatial (surface form) information of Korean words. (C) 2004 Elsevier Ireland Ltd. All rights reserved
Vibration and actuation characteristics of composite structures with a bonded piezo-ceramic actuator
No full textFor the design of vibration control systems of composite structures using piezo-ceramic actuators, it is necessary to obtain an accurate system model. Especially, the information related to natural modes, damping ratios and modal actuation forces appears in the governing state space equations. A refined finite element analysis based on the layerwise displacement plate theory has been performed to obtain the system parameters of composite plates with piezoelectric actuators. In this study, the present finite element method has the capability to take account of the stepped effect due to partly bonded piezo-ceramics. Also modal testing techniques have bean applied to identify the system parameters experimentally. Through the comparison of numerical results with experimental data, the validity of the numerical procedures has been proved.The present work was partially supported by the Korea
Science and Engineering Foundation (project No 96-0200-
05-01-3). This support is gratefully acknowledged
Improvement in the luminous efficiency using ramped-square sustain waveform in an AC surface-discharge plasma display panel
No full textThis paper proposes a new sustain waveform to improve the luminous efficiency of an alternate current plasma display panel (AC-PDP). The new sustain waveform is a superimposed waveform, which adds a ramp-waveform to a square-waveform, and has an increasing voltage slope between the rising and falling edge. This waveform can induce a longer-sustained discharge at the rising edge plus a self-erasing discharge at the falling edge, thereby improving the luminous efficiency. When compared with the conventional square sustain waveform, the proposed sustain waveform with a 9.3 V/mus voltage slope achieved a 65% higher luminous efficiency in a 4-in AC-PDP test panel even at a low frequency (62 KHz).This
work was supported by the Brain Korea 21 Project in 2001
GRP78 protects CHO cells from ribosylation
No full text
D-Ribose (Rib), a reactive glycation compound that exists in organisms, abnormally increases in the urine of diabetic patients and can yield large amounts of advanced glycation end products (AGEs), leading to cell dysfunction. However, whether cellular proteins are sensitive to this type of glycation is unknown. In this study, we found that cellular AGEs accumulate in Chinese hamster ovary (CHO) cells with increased Rib concentration and administration time. Mass spectrum analysis of isolated AGE-modified proteins from cell lysates showed that glucose-regulated protein 78 kD (GRP78) is one of the main ribosylated proteins. Co-immunoprecipitation assays further confirmed the interaction between AGEs and GRP78. Compared with D-glucose (Glc), Rib produced much more AGEs in cells. In kinetic studies, the first order rate constant of LDH released from CHO cells incubated with Rib was nearly 8-fold higher than that of Glc, suggesting that Rib is highly cytotoxic. Immunofluorescent co-localization analysis manifested partial superimposition of AGEs and GRP78, which were distributed throughout the endoplasmic reticulum. Western blotting showed that the expression of GRP78 is up-regulated and then down-regulated in CHO cells during Rib treatment. In the presence of Rib, the suppression of GRP78 expression either with transfected siRNA or with the inhibitor (-)-epigallocatechin gallate (EGCG) dramatically increased AGE levels and decreased cell viability compared with these parameters in the control groups. GRP78 over-expression decreased AGE levels and rescued the cells from Rib-induced cytotoxicity. These data indicate that GRP78 plays a role in preventing Rib-induced CHO cell cytotoxicity.</p
MỘT PHƯƠNG PHÁP PHÂN CỤM DỰA TRÊN CÂY KD-TREE CHO BÀI TOÁN TÌM KIẾM ẢNH
No full textTÓM TẮT Trong bài báo này, chúng tôi xây dựng một mô hình phân cụm dữ liệu cho bài toán tìm kiếm ảnh dựa trên cây BKD-Tree, một cải tiến cải tiến của cây KD-Tree, gồm: (1) lưu trữ các đối tượng đa chiều tại nút lá để tạo ra một mô hình phân cụm trên cơ sở phương pháp học bán giám sát; (2) tạo ra một cấu trúc cây cân bằng nhằm tăng hiệu suất cho bài toán tìm kiếm ảnh. Dựa trên cơ sở lý thuyết đề nghị, chúng tôi đề xuất mô hình truy vấn ảnh trên cây BKD-Tree và thực nghiệm trên bộ ảnh ImageCLEF (gồm 20.000 ảnh). Kết quả thực nghiệm của chúng tôi được so sánh với một số công trình gần đây trên cùng bộ dữ liệu để minh chứng tính hiệu quả của phương pháp đã được đề xuất. Theo kết quả thực nghiệm cho thấy phương pháp của chúng tôi là hiệu quả và có thể áp dụng được cho các hệ thống tìm kiếm ảnh tương tự theo nội dung
Một cải tiến của cây KD-TREE cho bài toán tìm kiếm ảnh
No full textTìm kiếm ảnh là một bài toán được quan tâm và đã có nhiều phương pháp được công bố trong thời gian gần đây. Trong nghiên cứu này, nhóm tác giả xây dựng cây BKD-Tree, là một cải tiến của cây KD-Tree, bao gồm: lưu trữ các đối tượng đa chiều tại nút lá của cây để tạo ra một mô hình phân cụm trên cơ sở phương pháp học bán giám sát; tạo ra một cấu trúc cây nhị phân cân bằng nhằm tăng hiệu suất cho bài toán tìm kiếm ảnh. Dựa trên cơ sở lý thuyết đã đề nghị, nhóm tác giả đề xuất mô hình truy vấn ảnh trên cây BKD-Tree đồng thời thực nghiệm trên bộ ảnh ImageCLEF (gồm 20.000 ảnh). Kết quả thực nghiệm được so sánh với một số công trình gần đây trên cùng bộ dữ liệu để minh chứng tính hiệu quả của phương pháp đã được đề xuất. Kết quả thực nghiệm cho thấy, phương pháp của nhóm tác giả là hiệu quả và có thể áp dụng được cho các hệ thống tìm kiếm ảnh tương tự theo nội dung
Native PAGE experiments on SL1-wt RNA kissing dimer (KD) in the presence of sub-stoichiometric amounts of NCp7, run in the TBE buffer
No full text<p><b>Copyright information:</b></p><p>Taken from "Nucleocapsid protein-mediated maturation of dimer initiation complex of full-length SL1 stemloop of HIV-1: sequence effects and mechanism of RNA refolding"</p><p></p><p>Nucleic Acids Research 2007;35(6):2026-2034.</p><p>Published online 6 Mar 2007</p><p>PMCID:PMC1874624.</p><p>© 2007 The Author(s)</p> KD of SL1-wt was incubated with NCp7 at ambient temperature for 18 h in the RNA strand-to-protein ratio of 2:0, 2:2, 2:1.6, 2:0.8, 2:0.4 and 2:0.2, as indicated. The upper band in each lane (‘LD’) corresponds to mature linear dimer, while the lower monomer band (‘M’) emanates from the residual KD that dissociates during PAGE in the TBE buffer. Increasing intensity of the monomer band and simultaneous decrease in the dimer band across the lanes correlates with the amount of NCp7 present in each complex
- …
