薄板의 加工性에 미치는 異方性에 관한 硏究(Ⅰ)

徐大敎,金東哲,禹鎬吉 충남대학교 공업교육연구소 1981 論文集 Vol.4 No.1

This study is concerned with the anisotropy which affects the workability of several different sheet metals. To do this, authors studied the earing through the deep drawing process, using the results which were obtained by studying the effect of the anisotropy of sheet metal in tensile yielding. The results through this study are as follows; 1) The corresponding maximum errors of the theoretical and experimental results in steel, brass, and aluminum plates in tensile yielding are 16%, 6%, and 5% respectively. 2) The earing of steel, brass and copper plates whose thickness are 0.62㎜ are two or three times as high as those of corresponding plates whose thickness are 0.34㎜. 3) The assumption of costa is satisfied in steel plate, but it is not satisfied in brass plate. It is hoped that the results of this study will be made reference to other works of sheet metal.

매립이 진행중인 일반폐기물 매립지에 있어서 침출수의 성상

이재오,서정인,이철희,권대원 嶺南大學校 環境問題硏究所 1995 環境硏究 Vol.14 No.2

매립지에 있어서 매립층의 폐기물의 분해상황을 평가하기 위하여, 매립이 진행중인 매립지의 침출수의 pH, 유기물질, 질소화합물, 중금속농도의 변화를 3년간 조사하였다. 그 결과 pH는 6.7 ~ 9의 범위로 나타났으며 매립기간의 경과와 함께 증가하는 경향을 보였다. BOD 및 COD의 농도범위는 각각 1,800 ~ 25,000 mg·???, 1,700 ~ 6,000mg·???로 나타났으며, 그 유출농도는 하절기에는 증가하고 동절기에는 감소하는 경향을 보였다. T-N의 농도범위는 1,000 ~ 4,000mg·???이었으며, 매립량의 증대와 함께 그 농도는 지속적으로 증가하였으며, 질소화합물의 대부분은 ?????????의 형태로 존재하였다. 한편, T-P의 평균농도는 20mg·???였다. SS의 농도는 150 ~ 600mg·??? 이었으며, 중금속의 유출농도는 매립기간의 경과와 함께 감소하는 경향을 보였다. 이와 같은 결과로부터 본 매립지의 매립폐기물의 분해는 혐기적상태에서 주로 이루어지고 있으며, 강우에 의한 미분해성 유기물의 세출현상이 활발한 것으로 추측되었다. The purpose of this research was to evaluate the decomposition properties of refuse by analysis of landfill leachate. The leachate was analyzed in terms of pH, organic and inorganic compounds, and heavy metals for 3 years. The results are as follows; The pH of leachate ranged from 6.7 to 9. BOD and COD were measured in the range of 1,800 ~ 25,000 mg·??? and 1,700 ~ 6,000 mg·???, respectively. It showed that the seasonal variation of BOD and COD appeared to increase in summer season, to decrease with decreasing temperature. Concentration of T-N was in the range of 1,000 ~ 4,000mg·???, it increased with augment of landfill volume, and the greater part of T-N existed form of ammonium nitrogen. The SS was observed in the range of 150~600 mg·??? and the average concentration of T-P was 20 mg·???. Also, concentration of heavy metals showed that it is tend to decrease in processing phase. From these results, it indicated that refuse of this landfill was decomposed in anaerobic condition, actively. Concentration of organic compounds increased in summer season. It results in the physical washout of organic compounds by rainfall and the extension of microbial decomposition activity inside landfill.

Outpatient Day-Care Management of Unruptured Intracranial Aneurysm: A Retrospective Cohort Study

Suh Dae Chul,Choi Yun Hyeok,Park Sang Ik,Yun Suyoung,Jeong So Yeong,Jeong Soo,Kwon Boseong,Song Yunsun 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.8

Objective: This study aimed to assess the outcomes of outpatient day-care management of unruptured intracranial aneurysm (UIA), and to present the risks associated with different management strategies by comparing the outcomes and adverse events between outpatient day-care management and management with longer admission periods. Materials and Methods: This retrospective cohort study used prospectively registered data and was approved by a local institutional review board. We enrolled 956 UIAs from 811 consecutive patients (mean age ± standard deviation, 57 ± 10.7 years; male:female = 247:564) from 2017 to 2020. We compared the outcomes after embolization among the different admission-length groups (1, 2, and ≥ 3 days). The outcomes included pre- and post-modified Rankin Scale (mRS) scores and rates of adverse events, cure, recurrence, and reprocedure. Events were defined as any cerebrovascular problems, including minor and major stroke, death, or hemorrhage. Results: The mean admission period was 2 days, and 175 patients (191 aneurysms), 551 patients (664 aneurysms), and 85 patients (101 aneurysms) were discharged on the day of the procedure, day 2, and day 3 or later, respectively. During the mean 17-month follow-up period (range 6–53 months; 2757 patient years), no change in post-mRS was observed compared to pre-mRS in 99.6% of patients. Cure was achieved in 95.6% patients; minimal recurrence that did not require re-procedure occurred in 3.5% patients, and re-procedure was required in 2.3% (22 of 956) patients due to progressive enlargement of the recurrent sac during follow up (mean 17 months, range, 6–53 months). There were eight adverse events (0.8%), including five cerebrovascular (two major stroke, two minor strokes and one transient ischemic stroke), and three non-cerebrovascular events. Statistical comparison between groups with different admission lengths (1, 2, and ≥ 3 days) revealed no difference in the outcomes. Conclusion: This study revealed no difference in outcomes and adverse events according to the admission period, and suggested that UIA could be managed by outpatient day-care embolization.

Response to “Familial Intracranial Aneurysm Requires Not Only Whole-Exome Sequencing, But Also Mitochondrial DNA Sequencing”

Suh Dae Chul,Lee Jong-Keuk,Seo Eul-Ju 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.5

Reversible Symptom Aggravation by Intake of Taurine-Rich Foods in Patients with Venous Congestive Myelopathy: Controlled Case Series Study

Suh Dae Chul,Jeong Soo,Choi Yun Hyeok,Cho Su Min,Yun Su Young,Son A Yeun,Lim Young Min,Kwon Boseong,Song Yunsun 대한신경중재치료의학회 2022 Neurointervention Vol.17 No.2

Purpose Reversible aggravation of myelopathy symptoms was observed after the intake of taurine-rich foods in patients with venous congestive myelopathy (VCM) caused by a spinal arteriovenous shunt (SAVS), and the taurine-challenge test was applied to demonstrate an association between taurine and VCM. Materials and Methods The current study reviewed any aggravation history of myelopathy symptoms, including walking difficulty, after consuming taurine-rich foods among 133 consecutive patients with a SAVS from a prospective institutional database from June 2013 to February 2021. The type of taurine-rich foods, demographic data, arteriovenous shunt level, and follow-up periods were obtained. For the controlled taurine challenge test, Bacchus® (Dong-A Pharmaceutical, Seoul, Korea), a taurine-rich drink, was given to patients who fulfilled test criteria of recovered VCM (pain-sensory-motor-sphincter scale ≥2, improvement of spinal cord signal intensity on magnetic resonance imaging, and follow-up >6 months after SAVS treatment) to confirm the disappearance of such aggravation. Results Ten patients had an aggravation history related to food. Webfoot octopus, small octopus, squid, crab, scallop, and taurine-rich energy drink (Bacchus®) were related to such aggravation in patients with VCM. Aggravation appeared about 30 minutes after food intake followed by expressions such as ‘I could not walk and collapsed to the ground’ and usually lasted for about 3 hours, followed by a slow recovery after taking rest. Four patients who met the test criteria underwent the taurine challenge with Bacchus® and revealed no further symptom aggravation, suggesting that taurine did not affect patients after recovery from VCM. Conclusion The association between taurine-rich food and reversible symptom aggravation can appear in patients with VCM and disappear after VCM treatment. Aggravation of venous hypertension in the spinal cord is suggested as a mechanism but further elucidation is needed.

Intracranial Artery Stenosis in Young Men Related to Habitual Periodic Cigarette Smoking in a Closed Space: Could It Be a New Syndrome?

Dae Chul Suh 대한신경중재치료의학회 2022 Neurointervention Vol.17 No.3

Computational Flow Dynamics of the Severe M1 Stenosis Before and After Stenting

Suh, Dae Chul,Ko, Young Bae,Park, Sung-Tae,Yoon, Kyunghwan,Lim, Ok Kyun,Oh, Jin Sun,Jeong, Yun Gyeong,Kim, Jong Sung Korean Society of Interventional Neuroradiology 2011 Neurointervention Vol.6 No.1

<P><B>Purpose</B></P><P>Computational flow dynamic (CFD) study has not been widely applied in intracranial artery stenosis due to requirement of high resolution in identifying the small intracranial artery. We described a process in CFD study applied to symptomatic severe intracranial (M1) stenosis before and after stenting.</P><P><B>Materials and Methods</B></P><P>Reconstructed 3D angiography in STL format was transferred to Magics (Materialise NV, Leuven, Belgium) for smoothing of vessel surface and trimming of branch vessels and to HyperMesh (Altair Engineering Inc., Auckland, New Zealand) for generating tetra volume mesh from triangular surface-meshed 3D angiogram. Computational analysis of blood flow in the blood vessels was performed using the commercial finite element software ADINA Ver 8.5 (ADINA R & D, Inc., Lebanon, MA). The distribution of wall shear stress (WSS), peak velocity and pressure in a patient was analyzed before and after intracranial stenting.</P><P><B>Results</B></P><P>Computer simulation of wall shear stress, flow velocity and wall pressure before and after stenting could be demonstrated three dimensionally by video mode according to flow vs. time dimension. Such flow model was well correlated with angiographic finding related to maximum degree of stenosis. Change of WSS, peak velocity and pressure at the severe stenosis was demonstrated before and after stenting. There was no WSS after stenting in case without residual stenosis.</P><P><B>Conclusion</B></P><P>Our study revealed that CFD analysis before and after intracranial stenting was feasible despite of limited vessel wall dimension and could reveal change of WSS as well as flow velocity and wall pressure.</P>

New grading system for the clinical evaluation of patients with spinal vascular lesions

Suh, Dae Chul,Song, Yunsun,Park, Danbi,Han, Minkyu,Lim, Young-Min,Park, Ji Eun,Lee, Sang Hun,Jeon, Sang Ryong,Kim, Kwang-Kuk Springer-Verlag 2018 Neuroradiology Vol.60 No.10

A Clinical Evaluation of the Optiscope Video System

Dae Il Park,Young Joong Suh,Jin Chul Song,Sung Kwan Choi,Eun Ha Suk 조선대학교 의학연구원 2015 The Medical Journal of Chosun University Vol.40 No.1

The aim of this study was to evaluate the efficacy of the Optiscope video system for anesthesia. Intubation was successful in all 60 patients. The first attempt success rate was 85%. The median time (IQR) [range] to intubation was 20 sec (14-43) [8- 420]. Seven patients required two attempts and in two patients, intubation of the trachea was achieved on a third attempt. The Optiscope video system is an effective and safe device for use in endotracheal intubation in adult patients with normal airways. Conduct of further clinical studies will be necessary to evaluate its role in patients with anticipated difficult airways.

New Concept in Cavernous Sinus Dural Arteriovenous Fistula : Correlation With Presenting Symptom and Venous Drainage Patterns

Suh, Dae Chul,Lee, Jeong Hyun,Kim, Sang Joon,Chung, Sun Ju,Choi, Choong Gon,Kim, Hyun Jeong,Kim, Chang Jin,Kook, Michael,Ahn, Hyo-Sook,Kwon, Sun Uck,Kim, Jong Sung Ovid Technologies Wolters Kluwer -American Heart A 2005 Stroke Vol.36 No.6

<P>BACKGROUND AND PURPOSE: An extradurally located cavernous sinus dural arteriovenous fistula (CSDAVF) exhibits different clinical behavior from other dural arteriovenous fistulas (DAVFs) located between 2 dural leaves. The aim of this study is to define angiographic types of CSDAVF associated with presenting symptom (Sx) and venous drainage patterns. METHODS: CSDAVFs during a mean of 23-month follow-up period of 58 patients (17 to 73 years, male:female ratio=8:50) were retrospectively analyzed. The 3 types of CSDAF, ie, proliferative (PT), restrictive (RT), and late restrictive (LRT) types, were categorized by the degrees and patterns of prominent arteriovenous shunt as well as venous flow. The status of the venous connection with CS and the presenting Sx patterns classified as orbital (OrbSxP), ocular (OcuSxP), cavernous (CavSxP), and cerebral (CerSxP) were associated with angiographic types as well as symptom onset, age, and gender. Correlations of discrete and categorical variables were statistically analyzed using the chi2 or Fisher exact test. RESULTS: PT (n=23) and RT (n=23) of CSDAVF were more common than LRT (n=12) (P=0.016) in patients with younger than 65 years and were related to OrbSxP (P=0.015) and CavSxP (P=0.038) in contrast to LRT to OcuSxP (P=0.004). Early onset of Sxs was related to the OrbSxP (P=0.08) and CavSxP (P<0.001). CerSxP (5%) was noted in RT or LRT. OrbSxP was related to the superior ophthalmic venous drainage (P=0.026) and CavSxP to the inferior petrosal sinus (P=0.046) and posterior fossa venous drainages (P=0.014). Seven patients revealed chronological progression of CSDAVF from PT to LRT and even to complete healing. CONCLUSIONS: CSDAVF presents as 3 distinctive angiographic types and is associated with presenting Sxs and venous drainage patterns.</P>