On the Strengthening Effects Affecting Tensile and Low Cycle Fatigue Properties of Low-Alloyed Seismic/Fire-Resistant Structural Steels

Jung‑Ho Sim,Tae‑Yeong Kim,Jun‑Yeon Kim,Chi‑Won Kim,Jun‑Ho Chung,Joonoh Moon,Chang‑Hoon Lee,Hyun‑Uk Hong 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.2

In the present study, low carbon ferritic and bainitic steels with different contents of Mo, Ti, and Nb were designed for bothseismic and fire-resistant applications. The microstructure of steels containing 0.3 wt% Mo–0.02 wt% Nb (‘A’ hereinafter)was mainly composed of bainite. By contrast, the microstructure of steels with 0.2 wt% Mo–0.13 wt% Ti (‘B’ hereinafter)consisted of ferrite with a high density of nano-sized (Ti,Mo)-rich MX precipitates. The results showed that the bainiticmicrostructure (‘A’ steel) was quite favorable to high-temperature strength and thermal stability. The yield strength of ‘A’ steelat both room and 600 °C temperatures increased consistently with increasing thermal exposure time (600 °C/200–1000 h),since the precipitation of NbC particles occurred while maintaining bainitic ferrite platelets with a high density of dislocationsduring exposure. In the ‘B’ steel, the formation of nano-sized (Ti,Mo)-rich MX particles was effective to impededislocation movement, leading to excellent plasticity (lower yield ratio) at room temperature. However, their contributionto precipitation hardening was not so much at 600 °C, as compared to the bainitic strengthening. During low cycle fatiguetests at room temperature, the main different feature between the two steels is that the ‘A’ steel showed cyclic softeningwhile cyclic hardening was evident in the ‘B’ steel. The bainitic microstructure showed a better fatigue life due to increasedductility manifested by cyclic softening, by which dislocation cell was developed.

정신분열병과 Glutathione S-Transferase M1유전자 다형성

배치운,조자현,김연주,김태석,김정진,이창욱,이수정,전태연,이철,백인호 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.5

Objectives : This study aimed to test the possible association between Glutathione S-Transferase Ml gene (GSTMl) variants and schizophrenia. Methods : One hundred and eleven inpatients with schizophrenia and 130 healthy controls were recruited. Genotyping was performed by polymerase chain reaction-based method. Results : The GSTMl null genotype was significantly more frequent in patients with schizophrenia than in controls (p=0.014, odd ratio=1.93, 95% confidence interva1=1.115-3.351), while GSTMl genotype vahants were not associated with either tardive dyskinesia (TD) or total Abnormal Involuntary Movement Scale (AIMS) scores. Conclusion : The present study suggests that the GSTMl polymorphism may confer susceptibility to the development of schizophrenia but not to TD, at least in Korean population.

비스판 변이주인 Bacillus polyfermenticus KD21의 주요 생균제 특성

정민용,정황영,하정욱,백현동 慶南大學校 附設 基礎科學硏究所 2002 硏究論文集 Vol.16 No.-

Bacillus polyfermenticus SCD which is commonly called as Bispan strain are being used for functional foods using the treatment of long-term intestinal disorders, since the live strains in the form of active endospores can successfully reach the target intestine in both humans and animals. B. polyfermenticus KD21 was obtained for higher sporulation through the NTG mutagenesis. The cells of B. polyfermenticus KD21 was treated for 24 h in artificial bile after incubation for 2 h in artificial gastric juice and final number of the strain was reached to around 10^8 CFU/㎖. In test of API ZYM kit, β-glucuronidase or β-glucosidase were not produced by B. polyfermenticus KD21. B. polyfermenticus KD21 was resistant to antibiotics such as nisin, tetracyclin, streptomycin, and rifamycin. B. polyfermenticus KD21 was shown to inhibit the growth of Listeria monocytogenes ATCC 19111 completely within 24 h of incubation, which indicates its bactericidal nature.

단백질-다당질 복합겔의 용해도 및 전기영동 특성에 미치는 몇가지 첨가제의 영향

정경임,이동선,하정옥 경남대학교 신소재연구소 1996 論文集 Vol.6 No.-

본 연구에서는 닭고기에서 조제한 근원섬유 단백질(MP)과 MP와 유청 단백질 분리물(WPI)의 혼합물, MP와 대두 단백질 분리물(SPI)의 혼합물 등의 3가지 종류의 단백질과 다당질로서 methyl cellulose, sodium alginate, xanthan gum을 택하여 단백질-다당질의 복합겔을 만들고 NaCl, NaSCN, propylene glycol, 2-mercaptoethanol들의 처리에 의해 단백질-다당질간의 상호작용에 기인하는 겔의 용해도 및 전기영동에 의한 겔 용해에 따른 상징액의 변화 등을 조사함으로써 단백질 식품의 기능적 특성에 미치는 영향을 고찰해 보았다. 겔 용해도는 대체로 모든 다당질에 대해 낮은 용해도를 나타냈으나 세 가지 단백질 시료에 대해 2-mercaptoethanol 처리시 가장 많은 단백질이 용해되어 나온 것으로 나타났다. 2-mercaptoethanol은 단백질간 상호작용, 즉 겔 망상구조를 이루는 sdisulfide 결합을 크게 방해함으로써 가장 높은 용해도를 나타낸 것으로 생각된다. 모든 시료에 대해 NaCl과 NaSCN 용액에 대해서는 아주 낮은 용해도를 보였는데, 이것은 NaCl과 NaSCN은 저 농도일 경우, 단백질 구조를 안정화함으로써 단백질간의 상호작용이 크게 증가되어 용해되는 단백질의 양이 극히 낮아진 것으로 보인다. Xanthan gum은 가장 겔 용해도가 낮았고, 특히 MP와 xanthan gum으로 이루어진 겔에서는 아주 극소량의 단백질이 용해되었다. Methyl cellulose 겔의 경우, 모든 용액에서 단백질이 거의 용해되어 나오지 않았다. 그러나, 1% WPI를 혼합한 경우 역시 겔 용해도가 낮았으며 여전히 MP의 단백질 성분은 용해되어 나오지 않았고 WPI의 주요성분인 α-lactalbumin과 β-latcoblobulin이 많이 용해되어 나왔다. 1% SPI을 혼합한 겔은 셀 용해도도 여전히 낮았으며 전기영동 결과에서도 SPI 성분의 단백질 band가 아주 미약하게 나타났다. 이것으로 보아 WPI는 다소 불안정한 겔을 형성하여 용해도를 증가 시키고 반대로 SPI는 겔을 안정화하여 단백질 용해도를 감소시켰으리라 짐작된다. Sodium alginate 겔의 경우, 단백질 용해도는 아주 낮았으나 3 가지 단백질 시료 모두 용해되어 나왔다. 이것으로 sodium alginate는 단백질과 다소 불안정한 겔을 형성한다는 것을 알 수 있다. X무소무 gum 겔에서도 역시 MP와 MP+SPI 혼합겔은 아주 낮은 겔 용해도를 뒷받침하듯 단백질 band를 거의 확인할 수 없었으나 WPI를 혼합한 겔만이 WPI의 주요성분인 α-lactalbumin과 β-latcoblobulin 성분이 용해되어 나왔다. 즉, methyl cellulose와 xsanthan gum 겔의 경우, 근원섬유 단백질은 거의 용해되어 나오지 않았고 유청 단백질 분리물의 성분이 많이 용해되어 나왔으며 대두 단백질 분리물은 단백질과의 결합력이 커 용해된 단백질 성분이 아주 미약했다. Sodium alginate 겔의 경우 모든 단백질 성분이 용해되어 나온 것으로 보아 sodium alginate는 단백질과 결합하여 불안정한 겔을 형성하는 것으로 나타났다. Interactions between polysaccharides and proteins occur widely in biological system. Their interaction in food system often plays a role in determining the functional properties of these systems. The effects of various reagents such as NaCl. NaSCN. propylene glycol and 2-mercaptoethanol on the gel solubility of heat-induced gels of protein and polysaccharide were studied. Protein samples were myofibrillar proteins(MP) extracted from chicken breast muscle and the combinations of MP plus whey protein isolate(WP1) and MP plus soybean protein isolate(SP1). As polysaccharides in preparation of gels, methyl cellulose, sodium alginate and xanthan gum were used. Protein- polysaccharide composite gels were formed by heating at 80 C for 30 min. In the effects of reagents on gel solubility, 2-mercaptoethanol had higher solubility than other reagents. indicating that 2-mercaptoethanol cleaved disulfide bonds in the protein-polysaccharide composite gels. In order to indicate the composition of protein solubilized from gels by the treatment of various reagents such as 0.1 M NaC1. 0.1 M NaSCN. 20% propylene glycol, 0.04 M 2-mercaptoethanol, the solubilized proteins were analyzed by SDS-PAGE. In methyl cellulose and xanthan gum gels. less protein was solubilized by reagents, but MP gels with WPI was solubilized more abundantly than SPI.

酸棗仁이 CT105에 의한 신경세포 상해 및 白鼠의 기억에 미치는 영향

정정욱,박창국,박치상,이소연,윤현덕,신오철 대한본초학회 2005 大韓本草學會誌 Vol.20 No.1

Objective: This study was designed to research whether demonstrate neuroprotective and memory enhancing effects of Z1BU, suggesting its beneficial actions for the treatment of AD. Methods: The present study investigated effects of the dichloromethane extract of Semen Zizyphi Spinosae(ZIBU) on neurotoxicity and reactive oxygen species(ROS) and nitric oxide(NO) formation in PC 12 cell line overexpressed with carboxyl-terminal 105 amino acid peptide fragment of amyloid precursor protein(CT105). In addition, the present study evaluated its radical scavenging activity and effects on acetylcholinesterase(AChE) activity. Furthermore, effects on neuronal loss in CAl area and cognitive deficits induced by scopolamine treatment were also evaluated in rats. Result: we found in this study that ZIBU significantly inhibited apoptotic neuronal death induced by CT105 overexpression in PC12 cells, with the IC_(50) value of 23 ㎍/ml. Based on phase-contrast and fluorescence microscopic examinations, ZIBU reversed morphological changes of CT105-expressed PC-12 cells. It was also found that Z1BU significantly induced neurite outgrowth and inhibited formation of ROS and NO.Z1BU scavenged DPPH radicals and inhibited AChE activity. Furthermore, it attenuated memory impairment induced by the injection of scopolamine in rats, based on passive avoidance test. Crystal violet staining of rat brain slices exhibited increase in the viability of pyramidal neurons in hippocampal CAI area. Conclusion: these results demonstrate neuroprotective and memory enhancing effects of ZIBU, suggesting its beneficial actions for the treatment of AD.

수입각증후군에 의한 급성 복증 1례

정은욱,지삼룡,이영태,박지훈,김동기,제인수,채두근,박성재,박은택,이연재,이상혁,설상영,정정명 白中央醫療院 2005 仁濟醫學 Vol.26 No.1

Afferent loop syndrome is an uncommon complication of a gastrectomy and Billroth Ⅱ reconstruction. It may cause symtoms at any time from the first postoperative day to many years after the gastrectomy. Afferent loop syndrome is characterized by abdominal pain, vomiting and elevation of serum amylase. Thus, it is difficult to differentiate afferent loop syndrome from other cause of acute pancreatitis. However, the history of gastrectomy can be an important clue for diagnosing afferent loop syndrome. We experienced one case of chronic afferent loop syndrome with acute pancreatitis. After appropriate management, the abdominal pain disappeared and serum amylase level decreased. We report this case with a review of relevant literatures.

양방향 링크를 갖는 개선된 DSR Ad Hoc 라우팅에 관한 연구

김현욱,이광배,김정일,최동근 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

In this paper, we enhanced the existing DSR routing protocol for ad hoc networks with bidirectional link. In mobile ad hoc network, mobile nodes themselves have router capability. Thus, for communication between two mobile nodes, the routing protocol for route set-up is required. DSR routing protocol, which is one of famous mobile ad hoc routing protocols, has the following problem: when route error occurs, the sending data packets drop as route recovery is delayed. In order to alleviate such problem, we modified route maintenance process of the existing DSR protocol so that the route recovery time from route error was shortened. As the result of performance evaluation, it was found the route recovery time of the proposed routing protocol was about 12 times faster than that of the existing DSR protocol. In addition, the data reception rate was more than 90 % for mobile ad hoc networks with slow mobility.

산후에 발병한 특발성 부갑상선 기능저하증 I 예

김정인,김상용,신병철,김경남,서영욱,이범주,김진화,배학연 朝鮮大學校 附設 醫學硏究所 2002 The Medical Journal of Chosun University Vol.27 No.2

Hypoparathyroidism is usually the result of an inadvertent surgical removal of all the parathyroid glands, In some instances, not all the tissues are removed, but the remainder undergoes vascular supply compromise secondary to the fibrotic changes in the neck after surgery, Previously, the surgery for hyperthyroidism was the most frequent cause of acquired hypoparathyroidism. Idiopathic hypoparathyroidism is a relatively rare disease that is characterized by hypocalcemia and hyperphosphatemia due to a parathyroid hormone deficiency of an unknown cause, It usually develops at a young age, and shows various clinical symptoms and signs accompanied with hypocalcemia. In addition, it is rarely associated with polyglandular autoimmune syndrome during the follow-up. Hypocalcemia and idiopathic hypoparathyroidism associated with labor and lactation are rarely reported condition previously. We here describe a case of a woman in whom the symptomatic severe hypocalcemia appeared after her delivery. We reviewed all the previously reported cases and suggest a possible physiological explanation for the association between pregnancy, lactation, and the appearance of symptomatic hypocalcemia.

유전알고리즘을 이용한 분산 데이터베이스 시스템에서의 컴퓨터 기종 선택과 데이터 분석

이재욱,조정복,고석범 東西大學校 1999 동서논문집 Vol.5 No.-

본 논문에서의 최적 분산 데이터베이스 구축에 관한 문제는 두 개의 결정을 나타낸다. 즉, 1) 각 사이트로의 적합한 컴퓨터 선택 2) 단편화된 파일의 할당이다. 또한, 제안된 모델에서는 1)waited response time 과 2) 투자비용 두 개의 목적함수를 고려한다. 각 컴퓨터와 파일의 할당의 영향에 따라 두 목적함수의 상관관계를 고찰한다. 제안된 수학적 모델은 경험적 탐색법 중의 하나의 유전적 알고리즘의 설계를 통해 효율적인 해의 탐색을 시도한다. 유전적 알고리즘(GA :Genetic Algorithm)의 설계에 있어서 요구 메모리의 최소화와 최적해 탐색시간의 최소화를 목적으로 한다. 끝으로, 수학적 모델과 해 알고리즘의 성능 검토를 위해 수치 예를 든다. Recently,DDS (Distributed Database System) has been often implemented on VAN (Value Added Network) as we know the amazing expansion of information network. DDS can yield significant cost and response time advantages over centralized systems for geographically distributed organizations. However, inappropriate design can result in high cost and poor response time. In a DDS design, the main problem is 1) how to select proper computer, and 2) how to allocate data fragment into poper nodes. This paper addresses DDS design problem of selecting a proper class of processor and allocating data files on VAN. Also, the formulated model includes two objectives, waited response time and investrment cost. GA (Genetic Algorithm) is developed to solve this mathematical formulation. A numerical experiment shows that the proposed method arrives at a good solution.

SCORM 기반의 XML 학습 컨텐츠 검색 시스템

최병욱,송미숙,조정원 한국컴퓨터교육학회 2003 컴퓨터교육학회 논문지 Vol.6 No.1

차세대 인터넷 표준 언어인 XML(eXtensible Markup Language)은 데이터(data)와 표현(presentation) 그리고 구조(Structure)가 구분되기 때문에 어느 환경에서나 재사용성이나 재구성이 용이한 장점을 보이고 있다. 본 논문에서는 XML 문서를 가상교육 시스템(Virtual Education System)의 멀티미디어 컨텐츠로 범위를 제한하여 사용자 위주의 효율적인 검색 시스템을 구현한다. 본 시스템에서는 가상교육 표준안으로 제안되고 있는 SCORM(Sharable Content Object Reference Model)에서 정치한 SCO(Sharable Content Object)단위의 메타데이터를 기반으로 컨텐츠를 설계하고 각 문서를 키워드, 엘리먼트, 애트리뷰트 단위로 색인한다. 또한 사용자 인터페이스에서 앨리먼트 검색화면을 구조적으로 구성해줌으로써 사용자가 DTD(Document Type Definition)fl 대한 사전지식 없이도 검색이 가능하며, XML-QL로 재구성된 XML 문서의 형태와 XSL(extensible markup language Stylesneet Language)을 이용한 HTML 형태의 두 가지 결과화면을 제시함으로써 사용자 선택의 폭을 넓혀준다. XML(eXtensible Markup Language), next generation internet standard language has the advantage of easy re-use and re-structure in other computing environment because it has the separate data, presentation and structure. In this paper, we implement the efficient retrieval system for the general user by limiting the XML documents on the multimedia learning contents for the virtual education system. The system design is based on SCO Metadata unit defined in SCORM as the proposed virtual education standard. Each XML documents has three indexes keyword, element and attribute. Also, it makes Possible to retrieve data without previous knowledge of the 078 by making the element retrieval screen structure for the user interface. And it gives the user various result screen formats such as XML and HTML by restructuring the retrieval result through XML-QL and XSL, respectively.