Evaluation of Hot Deformation and Dynamic Recrystallization Behaviors of Advanced Reduced-Activated Alloy (ARAA)

Sang‑Wook Kim,Hyeon‑Woo Son,Taek‑Kyun Jung,Young‑Bum Chun,Yi‑Hyun Park,Ji‑Woon Lee,Soong‑Keun Hyun 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

The hot deformation behavior of advanced reduced-activation alloy (ARAA) was investigated using hot torsion tests. Thefl ow stress decreased as deformation temperature increased and as strain rate decreased. The fl ow behavior demonstratedthe typical dynamic recrystallization (DRX). Based on the constitutive analysis of peak stress, the activation energy for hotdeformation was found to be 330.3 kJ mol −1 . Peak stress was analyzed as a function of the Zener–Hollomon parameter, andcalculated and experimental values were in good agreement. A DRX kinetic model for ARAA was derived with deformationconditions based on the Avrami-type model. It was confi rmed that the volume fraction of dynamically recrystallized grainsincreased as deformation temperature increased and as strain rate decreased. The necklace structure and grain boundarybulging were observed in the deformed microstructure of ARAA. The suggested DRX mechanism for ARAA during hotworking is discontinuous DRX.

요추 수술 예정 환자에서 실시한 선택적 신경근 차단술의 5년 추시 결과

심대무(Dae Moo Shim),김태균(Tae Kyun Kim),오성균(Sung Kyun Oh),최윤홍(Yun Hong Choi),이석중(Suk Jung Lee) 대한정형외과학회 2009 대한정형외과학회지 Vol.44 No.1

목적: 하지 방사통을 호소하는 환자의 수술 준비 과정에서 선택적 척추 신경근 차단술을 실시하고, 그 효과가 얼마나 오래 유지되는지를 알아 보고자 5년 이상 추시된 환자를 대상으로 분석하여 그 결과를 보고 하고자 한다. 대상 및 방법: 2000년 1월에서 2000년 12월까지 하지 방사통으로 타 병원 혹은 본원에서 수술적 치료를 권유받은 환자 중 수술 준비 과정에서 진단 및 치료 목적으로 선택적 척추 신경근 차단술을 시행한 환자를 대상으로 하였으며, 이중 5년 이상 추시가 가능하였던 69예를 대상으로 하였다. 결과분석은 진료기록부와 전화 인터뷰를 통해 하였으며. 신경차단술 시행군과 수술을 시행한 군의 치료결과 분석은 Kim's criteria (김의 평가기준), VAS(Visual analog scale) score를 이용하였다. 결과: 연구 대상 환자 69예 중 37예에서는 차단술 후에 증상 호전이 없어 수술을 시행하였고, 32예에서는 신경차단술 만으로 증상호전 되었다. 젊은 사람(60세 미만)에서 보존적 요법보다는 수술을 하는 경향이 많았으며, 이환 기간이 길수록(6개월 이상) 신경근 차단술 보다는 수술하는 경우가 높았다. 차단술 만으로도 호전된 32예의 환자 추시 결과상 다른 치료 없이 증상 호전이 지속되었던 환자는 17예(24.6%)였고 증상이 재발하여 추가 치료를 필요로 한 환자는 15예이었다. 이중 4예는 수술적 치료를 시행하였다. 결론: 수술이 예정된 하지 방사통 환자를 대상으로 수술 준비 기간 동안에 신경근 차단술을 시행하여 그 중 일부에서는 장기 추시에서도 증상 호전이 지속 되었다. 따라서 신경차단술은 수술 전에 한번 시도해 볼 만한 방법 중의 하나로 사료된다. Purpose: To evaluate the effectiveness of a selective nerve root block (SNRB) in patients with sciatica before surgery through a more than 5 year follow up. Materials and Methods: Between January 2000 and December 2000, patients with sciatica, who were recommended to undergo surgery to diagnose and treat sciatica by other clinics or at our hospital, were selected to undergo SNRB before surgery. Among them, 69 patients were followed up for 5 years. The analysis was based on the patients' medical records and telephone interviews, and the treatment results in the SNRB group and operation group were analyzed using Kim's criteria and the Visual Analog Scale score. Results: Among the 69 patients, there was no improvement in symptoms in 37 patients after SNRB. Therefore, they underwent surgery. The symptoms of the remaining 32 patients were improved by SNRB. Overall, younger patients and those with a longer symptom duration required surgery. Conclusion: SNRB was performed on patients with sciatica who were scheduled to undergo surgery. Some patients showed improvement in their symptoms in the long term. Therefore, SNRB should be considered as a treatment option prior to surgery.

A Study on the Factors Driving Biomass Production in OECD Countries

( Sang Jin Lee ),( Tae Kyun Kim ),( Jun Ho Yeo ),( Qing Long Lin ) 한국축산경영학회,농업정책학회(구 한국축산경영학회) 2014 농업경영정책연구 Vol.41 No.2

Biomass production and consumption depend on a combination of a nation`s intrinsic characteristics such as the environmental conditions, economic level, and so on. In this paper, using data from 12 OECD countries with 5 time intervals, we perform panel data analysis to investigate determinant factors on biomass supply. Results from the random effect analysis show that forest area, GDP and R&D are significant factors that influence biomass production. Forest land area is an important factor to increase biomass production. Biomass production and consumption increase with forest land area. There is an interesting relationship between the change of biomass production and forest land area. The increase in biomass production do not influence the decrease of forest land area, while forest land area increases with biomass production increase. It proves that forest resources can be a sustainable energy source for biomass without damaging forest. It also has been found that high levels of energy R&D investment and GDP are significant factors to stimulate biomass energy use.

Design of Robust Controller using Neural Network and Sliding Mode

Kim, Min-Chan,Kim, Tae-Kue,Park, Seung-Kyu,Kwak, Gun-Pyong,Ahn, Ho-Kyun,Yoon, Tae-Sung The Korea Institute of Information and Commucation 2010 Journal of information and communication convergen Vol.8 No.3

This paper derives a nominal state relationship (NSR) from the data of a nominal system. Through an example of a second order system, it is shown that the relationship can be derived only in the system with different real eigenvalues. In higher order system, the relationship is expressed by using neural network (NN). The derived NSR is used to design a noble sliding surface with a nominal system characteristic. By using the sliding surface, the robustness of the sliding mode control (SMC) is added to the pole-placement control.

Poster Session : PS 1026 ; GI Motility : Expression of Cancer Stem Cell Markers in Gastrointestinal Caner

( Sang Kyun Bae ),( Hong Sub Lee ),( Jeong Hyeon Cho ),( Kyung Won Park ),( Jeong Ho Kim ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Cancer stem cell (CSC) is known to play a key role in cancer occurrence, development and resistance to chemotherapy. Therefore, it is important to detect and eliminate CSC for leading to the complete cure of cancer. The aim of this study is to defi ne Trefoil Factor 3(TFF3) and Sex-determining region Y-related high mobility group box 4(SOX4) as markers for CSC by detecting their expression in cancer tissue for pilot study. Methods: Tissue slides were made with the tissues taken from 100 patients who underwent surgery for gastric cancer, and 34 patients underwent surgery for cholangio- pancreatic cancer. Immunohistochemical staining was performed for TFF3 and SOX4 in the tissue slides. The normal tissue was collected from histologically con- fi rmed tissues with no atypia obtained from cancer patients. Results: TFF3 had a higher expression rate in gastric cancer tissue (52%) compared to normal tissue (48%) but it did not show statistical signifi cance. SOX4 was highly expressed in cholangio-pancreatic cancer (23.5%) as compared to normal tissue (20.6%), but there was no statistical difference. Conclusions: Our data showed that the expression of TFF3 and SOX4 CSC was higher in cancer tissues than in normal tissues, but revealed no signifi cant difference as pilot study. Therefore, a study in a large number of patients might show that TFF3 and SOX4 are the CSC markers.

Linearization of T-S Fuzzy Systems and Robust Optimal Control

Kim, Min-Chan,Wang, Fa-Guang,Park, Seung-Kyu,Kwak, Gun-Pyong,Yoon, Tae-Sung,Ahn, Ho-Kyun The Korea Institute of Information and Commucation 2010 Journal of information and communication convergen Vol.8 No.6

This paper proposes a novel linearization method for Takagi.sugeno (TS) fuzzy model. A T-S fuzzy controller consists of linear controllers based on local linear models and the local linear controllers cannot be designed independently because of overall stability conditions which are usually conservative. To use linear control theories easily for T-S fuzzy system, the linearization of T-S fuzzy model is required. However, The linearization of T-S fuzzy model is difficult to be achieved by using existing linearization methods because fuzzy rules and membership functions are included in T-S fuzzy models. So, a new linearization method is proposed for the T-S fuzzy system based on the idea of T-S fuzzy state transformation. For the T-S fuzzy system linearized with uncertainties, a robust optimal controller with the robustness of sliding model control(SMC) is designed.

Types of Thromboembolic Complications in Coil Embolization for Intracerebral Aneurysms and Management

Kim, Hong-Ki,Hwang, Sung-Kyun,Kim, Sung-Hak The Korean Neurosurgical Society 2009 Journal of Korean neurosurgical society Vol.46 No.3

Objective : We describe our clinical experiences and outcomes in patients who had thromboembolic complications occurring during endovascular treatment of intracerebral aneurysms with a review of the literature. The types of thromboembolic complications were divided and the treatment modalities for each type were described. Methods : Between August 2004 and March 2009 we performed endovascular embolization with Guglielmi detachable coils for 173 patients with 189 cerebral aneurysms, including ruptured and unruptured aneurysms at our hospital. Sixty-eight patients were males and 105 patients were females. The age of patients ranged from 22-82 years (average, 58.8 years). We retrospectively evaluated this group with regard to complication rates and outcomes. The types of thromboembolic complications were classified into the following three categories: mechanical obstruction, distal embolic stroke, and stent-induced complications, which corresponded to types I, II, and III, respectively. A comparison of the clinical results was made for each type of complication. Results : Only eight patients had a thromboembolic complication during or after a procedure (4.6%). Of the eight patients, two had a mechanical obstruction as the causative factor; the other three patients had distal embolic stroke as the causative factor. The remaining three patients had stent-induced complications. In cases of mechanical obstruction, recanalization occurred due to the use of intra-arterial thrombolytic agents in one of two patients. Nevertheless, a poor prognosis was seen. In the cases of stent-induced complications, in one of three patients in whom a thrombus developed following stent insertion, a middle cerebral artery territory infarct developed with a poor prognosis despite the use of wiring and an intra-arterial thrombolytic agent. In the cases of distal embolic stroke, all three patients achieved good results following the use of antiplatelet agents. Conclusion : Treatment for thromboemboic complications due to mechanical obstruction and stent-induced complications include antiplatelet and intra-arterial thrombolytic agents; however, this cannot guarantee a sufficient extent of effectiveness. Therefore, active treatments, such as balloon angioplasty, stent insertion, and clot extraction, are helpful.

SEQUENTIAL CONFIDENCE INTERVALS WITH ${\beta}-PROTECTION$ IN A NORMAL DISTRIBUTION HAVING EQUAL MEAN AND VARIANCE

Kim, Sung-Kyun,Kim, Sung-Lai,Lee, Young-Whan 한국전산응용수학회 2007 Journal of applied mathematics & informatics Vol.23 No.1

A sequential procedure is proposed in order to construct one-sided confidence intervals for a normal mean with guaranteed coverage probability and ${\beta}-protection$ when the normal mean and variance are identical. First-order asymptotic properties on the sequential sample size are found. The derived results hold with uniformity in the total parameter space or its subsets.

The Effect of Barbiturate Coma Therapy for the Patients with Severe Intracranial Hypertension : A 10-Year Experience

Kim, Young-Il,Park, Seung-Won,Nam, Taek-Kyun,Park, Yong-Sook,Min, Byung-Kook,Hwang, Sung-Nam The Korean Neurosurgical Society 2008 Journal of Korean neurosurgical society Vol.44 No.3

Objective : Barbiturate coma therapy (BCT) has been known to be an useful method to control increased intracranial pressure (IICP) refractory to medical and surgical treatments. We have used BCT for patients with severe IICP during the past 10 years, and analyzed our results with review of literatures. Methods : We analyzed 92 semicomatose or comatose patients with Glasgow coma scale (GCS) of 7 or less with severe IICP due to cerebral edema secondary to parenchymal damages irrespective of their causes. Forty patients who had received BCT with ICP monitoring from January 1997 to December 2006 were included in BCT group, and fifty-two patients who had been managed without BCT from January 1991 to December 1995 were divided into control group. We compared outcomes with Glasgow outcome scale (GOS) and survival rate between the two groups. Results : Good outcome (GOS=4 and 5) rates at 3-month after insult were 27.5% and 5.8% in BCT and control group, respectively (p<0.01). One-year survival rates were 35.9% and 12.5% in BCT and control group, respectively (p<0.01). In BCT group, the mean age of good outcome patients ($37.1{\pm}14.9$) was significantly lower than that of poor outcome patients ($48.1{\pm}13.5$) (p<0.05). Conclusion : With our 10-year experience, we suggest that BCT is an effective treatment method for severe IICP patients for better survival and GOS, especially for younger patients.

Small Bowel Injury as a Complication of Lumbar Microdiscectomy : Case Report and Literature Review

Kim, Duk-Sung,Lee, Jung-Kil,Moon, Kyung-Sub,Ju, Jae-Kyun,Kim, Soo-Han The Korean Neurosurgical Society 2010 Journal of Korean neurosurgical society Vol.47 No.3

Small bowel injury resulting from unforeseen penetration of the anterior annulus fibrosus and longitudinal ligament is a rare complication of lumbar microdiscectomy. The patient complained of abdominal tenderness and distention immediately after microdiscectomy for L4-5 and L5-S1 disc herniation. Using abdominal computed tomography, we found several foci of air overlying the anterior aspect of the vertebral body at the L5-S1 level. Segmental resection of the small bowel including small tears and primary anastomosis of the jejunum were performed. Here, we present a case of intestinal perforation after lumbar microdiscectomy and discuss technical methods to prevent this complication with a review of literature.