• Proceedings of the KWS Conference
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• 2002.10a
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• pp.59-64
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• 2002

Effects of the aging treatments on the microstructure and strength of heat affected zone(HAZ) in the welds of a age-hardened Al-Mg-Si alloy, 5N01-T5, were investigated. The base metal aging treatments before MIG welding were conducted at 423K to 473K for 28.8ks Post weld heat treatment(PWHT) to recover the HAZ strength was performed at 448K for 28.8ks. Microstructure observations, hardness measurements and tensile tests were conducted to study properties of the MIG weld joints. The position of the softest region in HAZ where the hardness insufficiently recovered after natural aging and PWHT was at a distance of approximately 15mm from the center of the fusion zone. Hardness of the softest regions after natural aging and PWHT decreased with increase in the base metal aging temperature. TEM observation clarified that strengthening ${\beta}$"(Mg$_2$Si) precipitates and coarse ${\beta}$′ precipitates affected the hardnes of HAZ. Incomplete recover of hardness in HAZ after PWHT was caused by the precipitating of non-hardening ${\beta}$′ phase during the weld thermal cycle. In order to examine the effects of weldheat input and welding speed, the laser weld joints were also investigated and compared with the MIG weld ones. Laser welding had the narrower width of the softened regions in HAZ compared with MIG welding. The hardness of the softest regions of the laser welds after PWHT was higher than that of the MIG welds. Quantitative relations between hardness of the softest region and base metal aging temperature were obtained for both welding processes. Accordingly, the equations to estimate the strength of the weld joints after PWHT with varying base metal temperatures were proposed for MIG welding and laser welding.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.662-668
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• 2013

We examine the effects of El Ni$\tilde{n}$o on tropospheric ozone through the simulation of a Climate-Chemistry model for a 40-year period (1971-2010). The Empirical Orthogonal Function (EOF) analysis reveals that the tropospheric ozone concentration in the central-eastern Pacific decreases when the El Ni$\tilde{n}$o occurs, which is consistent with the observation. However, the increase of ozone over Indian Ocean-Indonesia regions is weak in the simulation compared to the observations. We analyze details of the 2006 El Ni$\tilde{n}$o event to understand the mechanism that caused the change of ozone due to El Ni$\tilde{n}$o. It is found that enhanced convection as well as higher water vapor followed by shortened lifetime has led to lower the tropospheric ozone. Downward motion induced by the changes of atmospheric circulation due to sea surface temperature forcing, together with the decrease of water vapor, has brought ozone produced in the upper troposphere over the Indian Ocean.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.185-193
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• 2010

Purpose: The purpose of this study was to investigated the effect of vision training methods on the visual function and sensation symptoms of patients with convergence insufficiency. Mehtods: The vision training observation group included 35 clients who had binocular vision disorders without opthalmic diseases or vertical phoria. They took the each vision training once a week for eight weeks and were investigated for the function and sensation symptoms changes of binocular vision. Results: According to the results, all vision training methods showed improvement of binocular vision function and sensation symptoms. For Worth 4 Dot test, Titmus test and red lenses observed the changes in fusion rate, all the training methods showed similar improvements. Conclusions: The study proved that vision training methods for patients with binocular vision was effective for the improvement of the phoria, function and sensation symptoms of these patients.

• Journal of Korean Foot and Ankle Society
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• v.7 no.1
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• pp.101-108
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• 2003

Purpose: To evaluate and analyze the incidence, clinical features, cause and surgical outcomes of iatrogenic hallux varus deformity after hallux valgus surgery. Materials and Methods: Twenty-six Hallux varus deformities after hallux valgus surgery were evaluated. Clinical tolerability, patient's satisfaction and the main causative factor for varus deformity were evaluated. Radiologically, we measured the 1st intermetatarsal angle and hallux valgus angle on pre- & postoperatively. Results: 10 cases of 26 varus deformities were clinically intolerable. The patients complaint of mainly cosmetic and shoe fitting problems rather than pain and the main cause of deformities were over-correction of 1 st intermetatarsal angle. Radiologically, the average 1st intermetatarsal angle was 2.4 degrees and the hallux valgus angle was -9.2 degrees. After varus correction surgery, the average follow up were 17 months and the average 1st intermetatarsal angle was 2.3 degrees and the hallux valgus angle was 2.7 degrees. The average score of AOFAS Hallux Metatarsophalangeal -Interphalangeal Scale was 91 points. Conclusion: The hallux varus deformity after hallux valgus surgery came from mainly overcorrection of 1 st intermetatarsal angle. The management composed of just observation, tendon transfer and fusion, and each method could get satifactory results with appropriate indication.

• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.1-14
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• 1996

Since the publication of the first bone scintiscans in 1962 three decades have elapsed. The bone scan has made great strides during this period, becoming one of the most commonly used nuclear imaging tests. In spite of the progress, however, the specificity of bone scan has remained relatively low. As the result it is a common practice to seek additional information from radiograph, CT scan and MR image, which is euphemistically termed as "image fusion or co-location." The basic reason is the inapplicability of the classical piecemeal analysis to interpreting planar and SPECT bone scans. Such analysis has its base on the observation of elemental features of morphology, which include the size, shape, contour, location, topography and internal architecture. The physiochemical profile may well also be included. Understandably, however, the miniatured images of the planar bone scan cannot provide these features in acceptable detail and the same holds true even with SPECT Images which are but sliced views of the reconstructed planar scans. Fortunately pinhole scanning has the capacity to portray both the morphological and chemical profiles of bone and joint diseases in greater detail through true magnification. The magnitude of pinhole scan resolution is practically comparable to that of radiography as far as gross anatomy is concerned. Thus, we feel strongly that pinhole scanning is a potential breakthrough of the long-lamented low specificity of bone scan. This presentation will discuss the fun-damentals, advantages and disadvantages and the most recent advances of pinhole scanning. It high-lights the actual clinical applications of pinhole scanning in relation to the diagnosis of infective and inflammatory diseases of bone and joint.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1773-1777
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• 2002

Reactive oxygen species(ROS) have been investigated to have pivotal roles on amyloidogenecity of $\beta-amyloidpeptide(A\beta)$, the major component of senile plaques in Alzheimer's disease(AD) brain. Addition of radical scavengers is one of the on-going strategies for therapeutic treatment for AD patients. Hsp104 protein including two ATP binding sites from Saccharomyces cerevisiae, as a molecular chaperone, was known to function as a protector of ROS generation when exposed to oxidative stress in our previous study. This observation has led us to investigate Hsp104 protein as a molecular mediator of $A{\beta}$ aggregation in this study. We have developed a new way of expression for Hsp104 protein using GST-fusion tag. As we expected, formation of $A{\beta}$ aggregate was protected by wild type Hsp104 protein, but not by the two ATP-binding site mutant, based on Thioflavin-T fluorescence. Interestingly, Hsp104 protein was observed to keep $A{\beta}$ from forming aggregates independent of ATP binding. On the other hand, disaggregation of $A{\beta}$ aggregates by wild type Hsp104 was totally dependent on the presence of ATP. On the other hand, mutant Hsp104 with two ATP binding sites altered exhibited no inhibition. Another effective antioxidant, hydrazine analogs of curcumin were also effective in $A{\beta}$ fibrilization as protectors against oxidative stress. Based on these observations we conclude that Hsp104 and curcumin derivatives, as protectors of oxidative stress, inhibit $A{\beta}$ aggregation in virto and can be candidates for therapeutic approaches in cure of some neurodegenerative disease.

• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1738-1742
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• 2009

Nanocrystalline Zn$Fe_2O_4$ oxide-semiconductor with spinel structure was synthesized by the polymerized complex (PC) method and investigated for its photocatalytic and photoelectric properties. The observation of a highly pure phase and a lower crystallization temperature in Zn$Fe_2O_4$ made by PC method is in total contrast to that was observed in Zn$Fe_2O_4$ prepared by the conventional solid-state reaction (SSR) method. The band gap of the nanocrystalline Zn$Fe_2O_4$ determined by UV-DRS was 1.90 eV (653 nm). The photocatalytic activity of Zn$Fe_2O_4$ prepared by PC method as investigated by the photo-decomposition of isopropyl alcohol (IPA) under visible light (${\geq}$ 420 nm) was much higher than that of the Zn$Fe_2O_4$ prepared by SSR as well as Ti$O_{2-x}N_x$. High photocatalytic activity of Zn$Fe_2O_4$ prepared by PC method was mainly due to its surface area, crystallinity and the dispersity of platinum metal over Zn$Fe_2O_4$.

• Carbon letters
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• v.21
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• pp.23-32
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• 2017

A drop weight impact test was conducted in this study to analyze the mechanical and thermal properties caused by the changes in the ratio of carbon fiber reinforced plastic (CFRP) to ethylene vinyl acetate (EVA) laminations. The ratios of CFRP to EVA were changed from 10:0 (pure CFRP) to 9:1, 8:2, 6:4, and 5:5 by manufacturing five different types of samples, and at the same time, the mechanical/thermal properties were analyzed with thermo-graphic images. As the ratio of the CFRP lamination was increased, in which the energy absorbance is dispersed by the fibers, it was more likely for the brittle failure mode to occur. In the cases of Type 3 through Type 5, in which the role of the EVA sheet is more prominent because it absorbs the impact energy rather than dispersing it, a clear form of puncture failure mode was observed. Based on the above results, it was found that all the observation values decreased as the EVA lamination increased compared with the CFRP lamination. The EVA lamination was thus found to have a very important role in reducing the impact. However, the strain and temperature were inversely propositional.

• Journal of the Korean Society of Costume
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• v.65 no.5
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• pp.14-34
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• 2015

The aim of this paper is to analyze the relationship between the inspirations and designs of Dries Van Noten's women's collections from 1994 S/S to 2014 F/W. From the research purpose the following questions arise: how are the brands of Dries Van Noten developed and what are the important features? What are 'the roots of inspiration' for Dries Van Noten's women's collections from 1994 S/S to 2014 F/W, and what are the aesthetic criterions of Noten's works? How are the roots of inspiration categorized, what are the features of each category, and how do these roots of inspiration influence the Noten's designs? The paper is a practical reference of how ideas turn to practical works and what is the relationship between inspiration and design. Researchers utilized a qualitative research method to provide a systematic review of the previous studies. To sum it up, roots of inspiration of Dries Van Noten's women's collections can be classified into seven categories: 'ethnic', 'trend & style', 'flowers', 'artists', 'interpretation', 'fabric & pattern' and 'multiple contents'. Through the roots of inspiration, sensibility of Belgium, inquiry of ethnic & oriental, Artists, England, longing of street fashion, 1920's & 1950's trend & style of French high fashion, romanticism, atmosphere of medieval, gypsy, punk and hippie are extracted and applied to the designs through cross impact. The identities of Dries Van Noten's women's collections are fusion and harmony of cross culture and diversity.

• Structural Engineering and Mechanics
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• v.52 no.5
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• pp.889-901
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• 2014

Very long life fatigue tests were carried out on 16Mn steel base metal and its welded joint by using the ultrasonic fatigue testing technique. Specimen shapes (round and plate) were considered for both the base metal and welded joint. The results show that the specimens present different S-N curve characteristics in the region of $10^5-10^9$ cycles. The round specimens showed continuously decreasing tendency while plate specimens showed a steep decreasing step and an asymptotic horizontal one. The fatigue strength of round specimen was found higher than plate specimen. The fatigue strength of as-welded joint was 45.0% of the base material for butt joint and 40% for cruciform as-welded joint. It was found that fracture can still occur in butt joint beyond $5{\times}10^6$ cycles. The cruciform joint has a fatigue limit in the very long life fatigue regime ($10^7-10^9$ cycles). Fatigue strength of butt as-welded joint was much higher as compared to cruciform as-welded joint. Improvement in fatigue strength of welded joint was found due to UPT. The observation of fracture surface showed crack mainly initiated from welded toe at fusion areas or geometric discontinuity sites at the surface in butt joint and from welded toe in cruciform joint.