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41.
Changhyun Roh Ho‐Young Lee Sang‐Eun Kim Sung‐Kee Jo 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(8):1130-1134
BACKGROUND: Over 170 million people, more than 3% of the world's population, suffer from the hepatitis C virus (HCV) infection and the rate of death from liver‐related mortality to HCV has increased. In respect of this, the development of assays for biological imaging should be urgently considered as an essential factor in diagnosis. RESULTS: A novel HCV‐detecting technique using a nanoparticle‐supported aptamer probe was demonstrated. With the aid of nanoparticle quantum dots (QDs) with carboxyl group as an imaging probe, and 5′‐end‐amine‐modified RNA oligonucleotide as a capturing probe, target HCV NS3 was visually detected on chip. The QDs‐based RNA aptamer for HCV NS3 showed high selectivity and specificity against other protein such as BSA. The detection limit of HCV NS3 protein was 5 ng mL?1 level. CONCLUSION: With a novel strategy for protein–aptamer interaction, the feasibility of applying QDs‐based fluorescent detection technique to HCV viral protein assay for the development of a protein biochip was demonstrated. This scheme of QDs‐mediated imaging with a target‐oriented specific RNA aptamer for the detection of infectious HCV diseases provides an efficient strategy and a promising new platform for monitoring applications. Copyright © 2010 Society of Chemical Industry 相似文献
42.
Kee Do Woo Jae Hwang Kim Eui Pyo Kwon Min Seok Moon Hyun Bom Lee Tatsuo Sato Zhiguang Liu 《Metals and Materials International》2010,16(2):213-218
To fabricate an Al-V matrix composite reinforced with submicron-sized Al2O3 and AlxVy (Al3V, Al10V) phases, high energy mechanical milling (HEMM) and sintering were employed. By increasing the milling time, the size of
mechanically milled powder was significantly reduced. In this study, the average powder size of 59 μm for Al, and 178 μm for
V2O5 decreased with the formation of a new product, Al-Al2O3-AlxVy, with a size range from 1.3 μm to 2.6 μm formed by the in-situ combustion reaction during sintering of HEM milled Al and
V2O5 composite powders. The in-situ reaction between Al and V2O5 during the HEMM and sintering transformed the Al2O3 and AlxVy (Al3V, Al10V) phases. Most of the reduced V reacted with excess the Al to form AlxVy (Al3V, Al10V) with very little V dissolved into Al matrix. By increasing the milling time and weight percentage of V2O5, the hardness of the Al-Al2O3-AlxVy composite sintered at 1173 K increased. The composite fabricated with the HEMM Al-20wt.%V2O5 composite powder and sintering at 1173 K for 2 h had the highest hardness. 相似文献
43.
Kyung Soon Jang Tae Won Kang Kee Sung Lee Chul Kim Tae-Woo Kim 《Journal of Mechanical Science and Technology》2010,24(6):1265-1271
Curved structural members are widely seen in our surroundings, such as railway supports in playgrounds resembling a c-ring
structure. The common geometry of the curved member consists of a segment of a circular ring with a uniform width. The curved
section is of constant width in most cardiovascular stents. This study focuses on curved strut members whose width changes
along the curved segment. The location of the maximum equivalent stress varies depending on the manner in which the width
changes. When the width is constant or larger toward the top, the maximum equivalent stress is developed at the top. Meanwhile,
when the area is reduced toward the bottom, the largest equivalent stress is developed some distance from the top. Simple
equations, based on the mechanics of materials and the theory of elasticity, were compared favorably with the results from
finite element analysis. Included are elaborations of the distribution of the change of stress. The suggested strategy of
changing the width, with refinements, could be applied to the optimal design of structural members, including pipes and medical
devices such as stents. 相似文献
44.
A. K. M. Fazle Kibria Young Hwan Mo Min Hee Yun Moon J. Kim Kee Suk Nahm 《Korean Journal of Chemical Engineering》2001,18(2):208-214
Multi-wall carbon nanotubes (MWNTs) were synthesized by catalytic decomposition of acetylene over Fe, Ni and Fe-Ni bimetallic
catalysts supported on alumina under various controlled conditions. The growth density and diameter of CNTs were markedly
dependent on the activation time of catalysts in H2 atmosphere, reaction time, reaction temperature, flow rate of acetylene, and catalyst composition. Bimetallic catalysts were
apt to produce narrower diameter of CNTs than single metal catalysts. For the growth of CNTs at 600 ‡C under 10/100 seem flow
of C2H2/H2 mixture, the narrowest diameter about 20 nm was observed at the reaction time of 1 h for 20Fe : 20Ni : 60Al2O3 catalyst, but at that of 1.5 h for 10Fe : 30Ni : 60Al2O3 catalyst. It was considered that the diameter and density of CNTs decreased with the increase of the growth time mainly due
to hydrogen etching. The growth of CNTs followed the tip growth mode. 相似文献
45.
When used as floor joists, the new mono-symmetric LiteSteel beam (LSB) sections require web openings to provide access for inspections and various services. The LSBs consist of two rectangular hollow flanges connected by a slender web, and are subjected to lateral distortional buckling effects in the intermediate span range. Their member capacity design formulae developed to date are based on their elastic lateral buckling moments, and only limited research has been undertaken to predict the elastic lateral buckling moments of LSBs with web openings. This paper addresses this research gap by reporting the development of web opening modelling techniques based on an equivalent reduced web thickness concept and a numerical method for predicting the elastic buckling moments of LSBs with circular web openings. The proposed numerical method was based on a formulation of the total potential energy of LSBs with circular web openings. The accuracy of the proposed method's use with the aforementioned modelling techniques was verified through comparison of its results with those of finite strip and finite element analyses of various LSBs. 相似文献
46.
On quasi-static crushing of thin-walled steel structures in cold temperature: Experimental and numerical studies 总被引:1,自引:0,他引:1
Jeom Kee Paik Bong Ju KimDae Kyeom Park Bong Seok Jang 《International Journal of Impact Engineering》2011,38(1):13-28
The aim of the study reported herein was to investigate the effects of low temperatures on the crushing characteristics of steel plated structures. The motivation of this study is for the analysis of ship collisions in Arctic waters. A series of tensile coupon tests were performed to examine their material behaviour at low temperatures, and then quasi-static axial crushing tests were carried out on thin-walled square tubes. The test tubes were made of ASTM A500-type carbon steel, and both the tensile coupon tests of the material and the crushing tests of the tubes were performed in a liquid nitrogen cooled chamber. To reflect the conditions of the Arctic environment more realistically, the tensile coupon tests of the material were also carried out in a dry-ice cooled chamber. LS-DYNA nonlinear finite element method simulations applying a practical approach of modelling techniques were performed to investigate the structural crashworthiness of the thin-walled steel tubes numerically. The tests in the liquid nitrogen cooled chamber showed that the fracture strain of the material was not affected (reduced) by temperatures as low as −80 °C, although fracture strain was significantly reduced below −100 °C. The fracture strain results obtained in the dry-ice cooled chamber, however, show this strain to be affected (reduced) by low temperatures even between 0 °C and −80 °C, which is equivalent to the Arctic environment. It was also observed that fracture occurs in thin-walled tubes under crushing loads at low temperatures. The LS-DYNA computations also detected the fracture behaviour of test tubes in cold temperatures in a relevant way. 相似文献
47.
Changho Lee Daeseok Han Byoungmok Kim Namin Baek Byung‐Kee Baik 《International Journal of Food Science & Technology》2013,48(5):984-991
Anthocyanin‐rich acetone extracts of barley grain of four hulless pigmented genotypes were investigated to determine their potential as functional food ingredients. The purple barley cultivar contained 11 anthocyanins, whereas only one anthocyanin, peonidin derivative, was observed in blue, black and yellow barley. The total anthocyanin content of pigmented barley genotypes ranged from 3.2 to 678.5 mg kg?1 in whole grain and from 4.5 to 1654.6 mg kg?1 in bran. The purple barley bran extract gave the highest DPPH radical scavenging capacity, superoxide radical scavenging capacity and total antioxidant activity. The half maximal inhibitory concentration (IC50) of angiotensin I‐converting enzyme (ACE) of anthocyanin‐rich extract of purple barley grain and bran was 8.77 and 4.54 mg mL?1, respectively. Purple barley appears to have great potential uses for the promotion of human health and development of nutraceuticals and functional foods. 相似文献
48.
Seung Jae Yang Jung Hyun Cho Kee Suk Nahm Chong Rae Park 《International Journal of Hydrogen Energy》2010
We report on an easy synthesis method for the preparation of a hybrid composite of Pt-loaded MWCNTs@MOF-5 [Zn4O(benzene-1,4-dicarboxylate)3] that greatly enhanced hydrogen storage capacity at room temperature. To prepare the composite, we first prepared Pt-loaded MWCNTs, which were then incorporated in-situ into the MOF-5 crystals. The obtained composite was characterized by various techniques such as powder X-ray diffractometry, optical microscopy, porosimetry by nitrogen adsorption, and hydrogen adsorption. The analyses confirmed that the product has a highly crystalline structure with a Langmuir specific surface area of over 2000 m2/g. The hybrid composite was shown to have a hydrogen storage capacity of 1.25 wt% at room temperature and 100 bar, and 1.89 wt% at cryogenic temperature and 1 bar. These H2 storage capacities represent significant increases over those of virgin MOF-5s and Pt-loaded MWCNTs. 相似文献
49.
Liquid-phase microextraction combined with hollow fiber as a sample preparation technique prior to gas chromatography/mass spectrometry 总被引:5,自引:0,他引:5
Two modes of liquid-phase microextraction (LPME) combined with hollow fiber (HF) were developed for gas chromatography/mass spectrometry (GC/MS). Both methodologies, that is, static LPME with HF and dynamic LPME with HF, involved the use of a small volume of organic solvent impregnated in the hollow fiber, which was held by the needle of a conventional GC syringe. In static LPME/HF, the hollow fiber impregnated with solvent was immersed in the aqueous sample, and the extraction processed under stirring; in dynamic LPME/HF, the solvent was repeatedly withdrawn into and discharged from the hollow fiber by a syringe pump. This is believed to be the first reported instance of a semiautomated liquid microextraction procedure. The performance of the two techniques was demonstrated in the analysis of two PAH compounds in an aqueous sample. Static LPME/HF provided approximately 35-fold enrichment in 10 min and good reproducibility (approximately 4%). Dynamic LPME/HF could provide higher enrichment (approximately 75-fold) in 10 min and even better reproducibility (approximately 3%). Both methods allow the direct transfer of extracted analytes to a GC/MS system for analysis. 相似文献
50.
Kee D 《Applied ergonomics》2002,33(1):51-62
The purpose of this study was to develop a new method for analytically generating three-dimensional isocomfort workspace for the upper extremities using the robot kinematics. Subjective perceived discomfort scores in varying postures for manipulating four types of controls were used. Fifteen healthy male subjects participated in the experiment. The subjects were asked to hold the given postures manipulating controls for 60 s in the seated position, and to rate their perceived discomfort during the following rest of 60 s using the magnitude estimation. Postures of the upper extremities set by shoulder and elbow motions, types of controls, and left right hand were selected as experimental variables, in which the L32 orthogonal array was adopted. The results showed that shoulder flexion and adduction-abduction, elbow flexion, and types of controls significantly affected perceived discomfort for postures operating controls, but hand used for operating controls did not. Depending upon the types of controls, four regression models predicting perceived discomfort were presented. Using the models, a sweeping algorithm to generate three-dimensional isocomfort workspace was developed, in which the robot kinematics was employed to describe the translational relationships between the upper arm and the lower arm/hand. It is expected that the isocomfort workspace can be used as a valuable design guideline when ergonomically designing three-dimensional workplaces. 相似文献