Dynamic Young's Modulus and Internal Friction in Polycrystalline Copper

Kang, Chang-Seog,Chang, Si-Young,Hong, Sung-Kil 대한금속재료학회 2003 METALS AND MATERIALS International Vol.9 No.5

An attempt has been made to measure the temperature dependence of dynamic Young's modulus together with the related variation of internal friction in polycrystalline copper. A mechanical spectroscopy study was employed using a standard servo hydraulic fatigue testing machine equipped with a scanning laser extensometer. Dynamic Young's modulus and internal friction were measured over a temperature range of 298 to 873 K at very low frequencies of 0.1, 0.05, and 0.01 Hz. One internal friction peak was observed over the ranges 450 to 700 K, together with marked decreases in the dynamic Young's modulus in the same temperature range. From a quantitative analysis of the experimental data with the relaxation strength, relaxation time, and activation energy, it is concluded that the peak phenomenon is due to grain-boundary sliding relaxation.

Aflatoxin B_1 투여가 急性 肝 病變에 미치는 영향에 對한 病理學的 硏究

장선문,이충식,강대영 충남대학교 의과대학 지역사회의학연구소 1989 충남의대잡지 Vol.16 No.1

In an attempt of elucidate the pathologic and histochemical changes of aflatoxin B_2-induced hepatie lesions, the present study in male Sprague-Dawley rats was undertaken to evalute the relation between pathologic change of the liver and histochemical changes of several enzymes : alkaline phosphatase, acid phosphatase and succinic dehydrogenase at 3. 9. 24. 48. 72, and 144 hours after single administration of aflatoxin B_1 by gastric tube. The aflatoxin B_1 was dissolved in peanut oil(0.5㎎ aflatoxin B_1 to 0.5ml peanut oil). Grouop of male rats received aflatoxin B_1 1㎎ per ㎏ of body weight, respectively. Control animals were given a similar volume of peanut oil alone. The results on morphologic and histochemical changes were as follows: 1. The necrotic change of liver was mainly periportal, and it became most severe at 24 hours and was more prominent in the large dose group than the small dose group. 2. Biliary ductular cell proliferation started to appear within 72 hours and after became regressed later in the small dose group, but it remained approximately 144 hours after exposure in the large dose group. 3. Electron microscopically, all three groups showed irregular nuclear membrane and nucleolar change characterized by segregation of granular and fibrillar elements. All the group showed cytoplasmie changes such as dilatation of rough endoplasmic reticulum with detached ribosome, hyperplasia of smooth endoplasmic reticulum, increased numbers of lipid droplets and mitochondrial alteration. The above change in the large dose group was more severe than those of the small dose group. 4. In the histochemical study of experimental animals, there was a decrease in the intensity of the staining reaction of alkaline phosphatase and succinic dehydrogenase within 24 hours and a progressive decrease in staining intensity was noted at 144 hours. And then the staining intensity of the acid phosphatase was similar to that shown by the control animal. In summary, the data obtained by present experiments indicate aflatoxin B_1 exerts periportal necrosis of hepatic lobules accompanied by bile ductular cell proliferation, and inhibition of protein synthesis, as jedged by elertron microscopic and histochemical changes.

Predictive Risk Assessment Using Cooperation Concept for Collision Avoidance of Side Crash in Autonomous Lane Change Systems

Hyunsoo Lee,Chang Mook Kang,Wonhee Kim,Woo Young Choi,Chung Choo Chung 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

We present an innovative approach to risk assessment using cooperation concept for collision avoidance of side crash for autonomous lane change system. The cooperation concept is proposed to check an available space in the target lane for lane change in a short period of the future. Before moving to the target lane, the ego vehicle needs to check whether the object vehicle is cooperative or not for the lane change. The object vehicles are indexed as cooperative driver (CD) or non-cooperative driver (NCD) through the conditions based on the relative longitudinal acceleration and the collision free time. If the object vehicle is CD, the ego vehicle moves toward the target lane within the original lane for the preparation of the lane change. The ego vehicle should keep its lateral position within the original lane until the situation for the lane change becomes safe. As soon as the risk assessment becomes safe, the lane change is performed. Therefore, lane change can be started in advance compared to the conventional methods. The proposed method was validated via computational simulation and experimental results.

Effect of Total Hip Arthroplasty on Ipsilateral Lower Limb Alignment and Knee Joint Space Width: Minimum 5-Year Follow-up

Choi Yun Seong,Park Jung-Wee,Kim Tae Woo,Kang Kee Soo,Lee Young-Kyun,Koo Kyung-Hoi,Chang Chong Bum 대한의학회 2023 Journal of Korean medical science Vol.38 No.20

Background: This study aimed to 1) assess the effect of total hip arthroplasty (THA) on coronal limb alignment, namely, the hip–knee–ankle angle (HKA), 2) identify factors that determine changes in the HKA, and 3) determine whether alignment changes influence the knee joint space width. Methods: We retrospectively evaluated 266 limbs of patients who underwent THA. Three types of prostheses with neck shaft angles (NSAs) of 132°, 135°, and 138° were used. Several radiographic parameters were measured in the preoperative and final radiographs (at least 5 years after THA). A paired t-test was used to confirm the effect of THA on HKA change. Multiple regression analysis was performed to identify radiographic parameters related to HKA changes following THA and changes in knee joint space width. Subgroup analyses were performed to reveal the effect of NSA change on the HKA change, and the proportion of total knee arthroplasty usage and changes in radiographic parameters between maintained joint space and narrowed joint space groups were compared. Results: The preoperative mean HKA was 1.4° varus and increased to 2.7° varus after THA. This change was related to changes in the NSA, lateral distal femoral angle, and femoral bowing angle. In particular, in the group with a decrease in NSA of > 5°, the preoperative mean HKA was largely changed from 1.4° varus to 4.6° varus after THA. The prostheses with NSA of 132° and 135° also led to greater varus HKA changes than those with an NSA of 138°. Narrowing of the medial knee joint space was related to changes in the varus direction of the HKA, decrease in NSA, increase in femoral offset. Conclusion: A large reduction in NSA can lead to considerable varus limb alignment after THA, which can have adverse effects on the medial compartment of the ipsilateral knee.

A Re-evaluation of the Concept of Topic

( Kang¸ Sun Young ),( Chang¸ Kyung Ki ) 현대영미어문학회 1983 현대영미어문학 Vol.1 No.-

Design of a shape memory composite(SMC) using 4D printing technology

Kang, Minkyu,Pyo, Youngjun,Jang, Joon young,Park, Yunchan,Son, Yeon-Ho,Choi, MyungChan,Ha, Joo wan,Chang, Young-Wook,Lee, Caroline Sunyong Elsevier 2018 Sensors and actuators. A Physical Vol.283 No.-

<P><B>Abstract</B></P> <P>A fused deposition modeling (FDM) tool was used to fabricate a shape memory composite (SMC) that combined a shape memory alloy (SMA) with a shape memory polymer (SMP). The SMA caused a shape memory effect due to a phase change between martensite and austenite phases, in turn due to a temperature change. Also, the SMP had a shape memory effect caused by changes in the proportions of hard and soft segments near the glass transition temperature (T<SUB>g</SUB>). Usually, common SMAs and SMPs are not reversible, so these materials do not go back to their original shapes once they are deformed. In this study, we fabricated 4D printing actuator via reversible SMC actuations using 3D printing technology. Nylon 12 was used as the 3D printing material in filament form. Moreover, the volume fraction of SMA to SMP was varied to find the optimum ratio for good operation cycles. A volume fraction of SMA:SMP of 1:5 showed the largest length change, of 8 mm, and the most rapid response time, of 4 s in overall dimension of 140mm×10mm×1mm (length×width×thickness).Thus, the SMC showed promising results for the application of stents and valve controllers that could be manufactured by 3D printing technology.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An 4D printed SMC actuator was fabricated using SMA and SMP with a FDM 3D printer. </LI> <LI> A volume fraction of SMA:SMP of 1:5 showed the largest length change of 8 mm, and the most rapid response time of 4 s. </LI> <LI> The reversible actuator mechanism explains the SMC actuation via each shape memory effect. </LI> <LI> SMC showed potential application for stents and valve controllers via 3D printing technology to achieve customized designs. </LI> </UL> </P>

사염화탄소 투여 흰쥐에서 간섬유화 진행에 따른 Propranolol 의 약동학적 지표들의 변화

이민호,강주섭,강문수,윤병철,이오영,함준수,변재원,윤창옥 대한간학회 2001 Clinical and Molecular Hepatology(대한간학회지) Vol.7 No.2

Background/Aims : This study was designed to determine the effect of hepatic fibrotic severity on pharmacokinetics of propranolol in CC1q - treated rats. Methods - 1 mL/kg of 10% CC14 in olive oil was injected intramuscularly to rats twice weekly for 4, 6, 8 and 10 weeks, respectively (n=6). Control (n=6) was a sham - injected equal dose of olive oil for 10 weeks. After intravenous bolus injection of 2 mg/kg propranolol to rats, the serum propranolol concentrations were analyzed for 4 hours at various time points by a HPLC - fluorimetric system, and pharmacokinetic parameters such as Co, MRT, AUC, Vdss, tl/2(p) and CLp were determined. Then, a small amount of hepatic tissue was obtained and subjected to determination of the hepatic 4 - hydroxyproline content, which confirmed the hepatic fibrotic severity. Results : The serum concentrations of propranolol at 0.5, 1, 2 and 4 hours were significantly increased in CC1q-treated rats (p$lt;0.01). In proportion to the duration of CC4 treatment, Co and AUC were significantly increased, and Vdss and CLp were significantly decreased (p$lt;0.001). But MRT and t1/2(β) were not significantly changed. The hepatic 4 -hydroxyproline content was gradually increased in CC4-treated rats (p$lt;0.001). Conclusion - Gradual changes in pharmacokinetic parameters of propranolol were seen to be dependent on the hepatic fibrotic severity. We suggest that gradual dosage modification, according to their hepatic fibrotic severity, is necessary for many drugs administered to patients with chronic liver disease.(Korean J Hepatol 2001;7:181-188)

Nurses' management of older patients with post-anesthesia delirium: A Q methodology approach

Kang,Minyeong(Minyeong Kang),Kim,Eun Young(Eun Young Kim),Chang,Sung Ok(Sung Ok Chang) 한국노인간호학회 2022 노인간호학회지 Vol.24 No.4

Purpose: This is an analysis of the experiences of nurses in Post Anesthesia Care Units (PACUs) in caring for older patients with emergence delirium using the Q-methodology. Methods: The Q-methodology, which is used to explore and understand human subjectivity, was applied. Thirty nurses who had experiences in providing nursing for delirium in older patients after surgery in a PACU participated in this study. Results: This study revealed three factors regarding the frame of reference of PACU nurses in detecting and managing older patients' emergence delirium: “detect the deviant changes leading to instability”, “focus on the patient’s degree of cognitive recovery within the framework of recovery time”, and “awareness of possible clues based on the patient’s underlying disease(s)”. Conclusion: These findings are expected to be utilized as a basis for more practical and accessible PACU nurse delirium education that reflects nurses’ subjective viewpoints explained by the three identified factors.

18–30세 사이에 발생하는 뇌경색의 특징, 다기관 레지스트리 연구

장윤경,송태진,김용재,허지회,이경열,김영은,장민욱,조수진,강석윤 이화여자대학교 의과학연구소 2017 EMJ (Ewha medical journal) Vol.40 No.3

Objectives: Although there have been several reports that described characteristics for young age stroke, information regarding very young age (18–30 years old) has been limited. We aimed to analyze demographic factors, stroke subtype, and 3-month outcome in acute ischemic stroke patient who have relatively very young age in multicenter stroke registry. Methods: We evaluated all 122 (7.1%) consecutive acute ischemic stroke (within 7 days after symptom onset) patients aged 18 to 30 from 17,144 patients who registered in multicenter prospective stroke registry, 1997 to 2012. Etiology was classified by Trial of Org 10172 in Acute Stroke Treatment criteria. Stroke severity was defined as National Institutes of Health Stroke Scale (NIHSS) and stroke outcome was defined by modified Rankin scale (mRS) at 3 months after index stroke. Results: The mean age of all included patients was 25.1±3.7 years and 76 patients (62.2%) were male. The median NIHSS at admission was 4. Considering stroke subtype, 37 patients (30.3%) had stroke of other determined etiology (SOD), 37 (30.3%) had undetermined negative evaluation (UN) and 31 (25.4%) had cardioembolism (CE) were frequently noted. After adjusting age, sex and variables which had P<0.1 in univariable analysis (NIHSS and stroke subtype), CE stroke subtype (odds ratio, 4.68; 95% confidence interval, 1.42–15.48; P=0.011) were significantly associated with poor functional outcome (mRS≥3). Conclusion: In very young age ischemic stroke patients, SOD and UN stroke subtype were most common and CE stroke subtype was independently associated with poor discharge outcome.

삼출성 중이염 환자에서의 혈중 및 아데노이드 면역글로불린 E의 면역혈청학적 연구

장혁순,강성호,유창수,김성현,이병돈,박영진,윤세동,안희영,강주원 순천향의학연구소 1997 Journal of Soonchunhyang Medical Science Vol.3 No.1

Otitis media with effusion (OME) is one of the most common disease in children but its pathogenesis is not clear. In particular the role of allergy has revealed conflicting support with widely varing opinions as to its importance. Within recent years, striking biochemical and immunochemical analytic techniques have opened a new approach the study of otitis media with effusion. So we focused on distributions of IgE in adenoid tissue and serum IgE levels. Authors compared the serum IgE and the distribution of IgE in adenoid tissue between the 20 patients underwent tonsillectomy, adenoidectomy and ventilating tube insertion and control group of 11 patients underwent tonsillectomy and adenoidectomy. The results were as follows; 1. In the distribution of IgE in adenoid tissue, there was a significant increase in the group of patients with OME compared to the control group (P<0.01). 2. In the analysis of serum IgE levels, the levels of IgE in the OME patients an control group were higher than normal level, although the level of IgE in the OME patients were less than that of control group, there was no significance P>0.05).