앵커볼트 인발거동의 파괴역학적 해석

조영혁,김인순,변근주,송하원 연세대학교 산업기술연구소 1996 논문집 Vol.28 No.2

Anchor bolts embedded in concrete, used to transfer local loads into structures, are important structural details. The accurate predictions of the ultimate tensile capacity of the anchor bolts governed by the concrete cone failure are very important. The objectives of this study are to predict the fracture behavior of the concrete and to obtain the tensile capacity numerically for the pull-out of anchor bolts embedded in concrete. For this purpose, the methods to evaluate the ultimate tensile capacity of the anchor bolts embedded in concrete are summarized and the fracture behavior and cracking model of concrete are studied. From the concrete fracture analysis based on finite element modeling of the pull-out test, the fracture behavior of concrete including the ultimate tensile capacity of the anchor bolt is obtained. From the comparison between the numerical results and the experimental data, it is shown that the smeared modeling for the numerical predictions of the progressive fracture of concrete due to the pull-out of anchor bolts can be improved by using the line of interface elements along the crack path.

유방암에서 종양의 크기와 액와림프절 전이의 상관성을 근거로 한 액와림프절 절제술의 생략

송근영,조현진,김권천 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.2

Purpose: The aim of this study is evaluation of the relations between axillary lymph node status and tumor size, and then applied the omission criteria of axillary lymph node dissection in early breast cancer. Materials and Methods: We reviewed 110 patients underwent radical mastectomy and axillary lymph node dissection in breast cancer at Chosun university Hospital between Feb. 1996 and Mar. 2003. We evaluated the correlations between clinicopathologic factors, axillary lymph node status, and presence of metastasis. Results: Correlations between clinicopathologic factors and axillary lymph node status were statistically significant (p=0.01). Correlation between locoregional metastasis and distant metastasis and axillary lymph node status was significant (p=0.03). Results from the number of histologically-positive lymph nodes were significant (p=0.02) as that of lymph node status. Conclusions: The rate of axillary lymph node metastasis in Tla breast cancer is minute. And, preoperative evaluations and postoperative routine radiation therapy can control the axillary lymph node metastasis in Tla breast cancer. So, omission of the axillary lymph node dissection in Tla breast cancer may be considerable.

최적배치를 위한 워드모델 및 비트연산자 개발

김영근,조경호 제주대학교 공과대학 첨단기술연구소 2006 尖端技術硏究所論文集 Vol.17 No.1

In this paper, a new nesting method based upon the 'word representation' of parts and raw sheets is proposed to improve the performance of pixel-based nesting. In this new representation, the pixel patterns of parts and sheets are converted to proper word-sets. And all the usual nesting processes such as part allocations, de-allocations, overlap testings and etc. can be performed through the 'bit operations' between words of the parts and sheets. The proposed method shows some possibilities to overcome the shortcomings of the traditional pixel-based nesting. In addition, a new efficient gap searching method based upon the quad-tree is presented to locate proper allocation positions of the parts.

수면무호흡증의 다원수면기록 소견

김용조,이선우,왕성근 대한생물치료정신의학회 1996 생물치료정신의학 Vol.2 No.2

To identify the clinical characteristics of sleep apnea syndrome in Korean, author analyzed 24 cases of polysomnographic findings statistically, diagnosed as sleep apnea syndrome during May, 1995 to July,1996. The results were summarized as follows: 1. The mean age of subjects was 35.7 years, the distribution of age was 12 to 64 years, and male to female sex ratio was 5:1. 2. As for mean values of sleep parameters, total bed time was 429.8 minutes, waking after sleep onset was 93.4 minutes, total sleep time was 336.1 minutes and sleep efficiency was 77.7%. 3. The proportions of sleep stage 1, stage2,slow wave sleep, REM sleep, and movement time to total sleep time were 13.1%, 39.4%, 24.4%, 20.8%, and 2.2% respectively. 4. Mean AI(apnea index) was 28.7 and RD(respiration disturbance index ) was 34.3. 5. Waking after sleep onset correlated with total sleep time and sleep efficiency negatively, and with sleep stage 1 positively. Sleep efficiency correlated with sleep stage 1 negatively, and sleep stage 1 correlated with slow wave sleep negatively.

VDT작업별 정신사회적 스트레스와 근골격계 장애에 관한 연구

백남종,강종두,주영수,배인근,권호장,박종만,조수헌,김돈규,김재용,최홍렬 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.4

It has been hypothesized that jobs that have both high psychological demands and low decision latitude("job strain") can lead to musculoskeletal disorder. The objective of this study was to test whether job strain was correlated with the presence of work-related musculoskeletal disorder, especially myofascial pain syndrome(MPS). Information on demographic factors, confounders such as household load and taking care of children or not, and scores for decision latitude, job demand, and social support was obtained by self-administered questionnaire, which had been developed in Korean language, by adopting NIOSH instrument and Extended Karasek Model(16 items). All subjects were also examined by rehabilitation medicine specialists for musculoskeletal disorders. Subjects(n=370) could be categorized into 4 groups, these were, housewives(n=89), shipyard CAD workers(n=89), general female workers(n=79; nurses, insurance counselors, public officials, clerks, etc), and telephone directory assistance operators(n=113). Results from univariate analyses indicated that all demographic factors, all confounders, scores for decision latitude and social support were not associated with the risk of musculoskeletal disorder. However, score for job demand was higher in musculoskeletal disorder cases than others. In subgroup analysis, this association was convinced again, in telephone directory assistance operators. Job strain model showed that the group of telephone directory assistance operators was high-stain group, and OR of musculo skeletal disorder was 2.446(95% C. I. : 1.174, 5.096), when comparing this with the low strain group. In conclusion, job strain is a risk factor for work-related musculoskeletal disorder.

103-Gb/s Long-Reach WDM PON Implemented by Using Directly Modulated RSOAs

Keun Yeong Cho,Ui Hyun Hong,Takushima, Y.,Agata, A.,Sano, T.,Suzuki, M.,Chung, Y. C. IEEE 2012 Photonics Technology Letters Vol.24 No.3

<P>We propose and demonstrate a long-reach wavelength-division-multiplexed passive optical network (WDM PON) capable of providing 100-Gb/s service to each subscriber, for the first time to the best of our knowledge. For cost-effectiveness, this network is implemented in loopback configuration by using directly modulated reflective semiconductor optical amplifiers (RSOAs) at 25.78 Gb/s. For the modulation of the RSOA at such a high-speed, we have to minimize the electrical parasitics by using the butterfly package. Also, to overcome the limited bandwidth of the RSOA, we utilize the electronic equalization technique at the receiver. We use four RSOAs at each optical network unit for the 103-Gb/s upstream transmission. The operating wavelengths of these RSOAs are separated by the free-spectral range of the cyclic arrayed waveguide gratings used at the central office and remote node (RN) for (de)multiplexing the WDM channels. We extend the maximum reach of this WDM PON to be >; 120 km by using Erbium-doped fiber amplifiers at the RN. The results show that the error-free transmission can be achieved for all WDM channels in the wavelength range of >; 35 nm with sufficient power margins.</P>

Effects of Reflection in RSOA-Based WDM PON Utilizing Remodulation Technique

Cho, Keun Yeong,Lee, Yong Jik,Choi, Hyeon Y.,Murakami, Ayako,Agata, Akira,Takushima, Yuichi,Chung, Yun C. IEEE 2009 Journal of Lightwave Technology Vol.27 No.10

<P> We investigate the effects of the discrete reflection on the performances of upstream and downstream signals in the wavelength-division-multiplexed passive optical network (WDM PON) implemented in a single-fiber loopback configuration using the reflective semiconductor optical amplifiers (RSOAs). We first analyze the optical beat interference (OBI) noise caused by the discrete reflection, and clarify the relation between the reflection tolerance and the network's operating conditions such as the RSOA gain, the link loss, and the location of the reflection point, etc. The results show that the impact of the reflection can be expressed by using the effective crosstalk level. We then measured the reflection tolerance of the RSOA-based WDM PON, in which the downstream signal operating at 1.25 Gb/s is remodulated by the RSOA at the subscriber's site for the transmission of 155-Mb/s upstream signal. The reflection tolerances are measured to be in the range of <TEX>$-42$</TEX> to <TEX>$- 35~\hbox{dB}$</TEX> for the downstream signals and <TEX>$-29$</TEX> to <TEX>$-19~\hbox{dB}$</TEX> for the upstream signals, depending on the RSOA gain. These small reflection tolerances are caused by the fact that the reflected light is re-amplified by the RSOA. We also show that the dependence of the reflection tolerance on the RSOA gain can be explained by using the effective crosstalk level. These results are used to evaluate the impacts of the unwanted discrete reflections on the RSOA-based WDM PON. </P>

Metformin ameliorates monosodium-iodoacetate-induced Osteoarthritis via regulation of mitochondria and the autophagy-inflammation-cell death axis

Keun Hyung Cho,Hyun Sik Na,Ji Ye Kwon,Seon-Yeong Lee,Seung Hoon Lee,A Ram Lee,Jin Seok Woo,KyungAh Jung,Jeong-Won Choi,Dong Hwan Lee,Hong-Ki Min,Sung-Hwan Park,Seok Jung Kim,Mi-La Cho 한국실험동물학회 2022 한국실험동물학회 학술발표대회 논문집 Vol.2022 No.7

SPIN90 dephosphorylation is required for cofilin-mediated actin depolymerization in NMDA-stimulated hippocampal neurons

Cho, In Ha,Lee, Min Jung,Kim, Dae Hwan,Kim, Bora,Bae, Jeomil,Choi, Kyu Yeong,Kim, Seon-Myung,Huh, Yun Hyun,Lee, Kun Ho,Kim, Chong-Hyun,Song, Woo Keun Springer Basel 2013 Cellular and molecular life sciences Vol.70 No.22

<P>Actin plays a fundamental role in the regulation of spine morphology (both shrinkage and enlargement) upon synaptic activation. In particular, actin depolymerization is crucial for the spine shrinkage in NMDAR-mediated synaptic depression. Here, we define the role of SPIN90 phosphorylation/dephosphorylation in regulating actin depolymerization via modulation of cofilin activity. When neurons were treated with NMDA, SPIN90 was dephosphorylated by STEP61 (striatal-enriched protein tyrosine phosphatase) and translocated from the spines to the dendritic shafts. In addition, phosphorylated SPIN90 bound cofilin and then inhibited cofilin activity, suggesting that SPIN90 dephosphorylation is a prerequisite step for releasing cofilin so that cofilin can adequately sever actin filaments into monomeric form. We found that SPIN90 YE, a phosphomimetic mutant, remained in the spines after NMDAR activation where it bound cofilin, thereby effectively preventing actin depolymerization. This led to inhibition of the activity-dependent redistribution of cortactin and drebrin A, as well as of the morphological changes in the spines that underlie synaptic plasticity. These findings indicate that NMDA-induced SPIN90 dephosphorylation and translocation initiates cofilin-mediated actin dynamics and spine shrinkage within dendritic spines, thereby modulating synaptic activity.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1007/s00018-013-1391-4) contains supplementary material, which is available to authorized users.</P>

Antioxidative Lithium Reservoir Based on Interstitial Channels of Carbon Nanotube Bundles

Cho, Seok-Kyu,Jung, Gwan Yeong,Choi, Keun-Ho,Lee, Jiyun,Yoo, JongTae,Kwak, Sang Kyu,Lee, Sang-Young American Chemical Society 2019 NANO LETTERS Vol.19 No.9

<P>Lithium (Li) metal has garnered considerable attention in next-generation battery anodes. However, its environmental vulnerability, along with the electrochemical instability and safety failures, poses a formidable challenge to commercial use. Here, we describe a new class of antioxidative Li reservoir based on interstitial channels of single-walled carbon nanotube (SWCNT) bundles. The Li preferentially confined in the interstitial channels exhibits unusual thermodynamic stability and exceptional capacity even after exposure to harsh environmental conditions, thereby enabling us to propose a new lithiation/delithiation mechanism in carbon nanotubes. To explore practical application of this approach, the Li confined in the SWCNT bundles is electrochemically extracted and subsequently plated on a copper foil. The resulting Li-plated copper foil shows reliable charge/discharge behavior comparable to those of pristine Li foils. Benefiting from the confinement effect of the interstitial channels, the SWCNT bundles hold great promise as an environmentally tolerant, high-capacity Li reservoir.</P> [FIG OMISSION]</BR>