외부 프리스트레스 도입에 의한 노후된 콘크리트 거더교의 보강성능평가

박승범,홍석주,이봉춘,장석호,권혁준 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.1

One of the promising methods to enhance the flexural strength of a externally prestressed girder is to place the tendons with large eccentricities. The analysis and design of composite girders prestressed by external tendons involve difficulties related mainly to the position of anchorages and the construction sequences. This study was conducted on the concrete bridges reinforced by the continuous girders and the external prestressing. The test results in this study showed that the external prestressing of a composite girder increased the range of the elastic behavior, reduced deflections, increased ultimate strength, and added to the redundancy by providing the multiple stress paths.

MgCl₂溶液內에서 STS 304 HP Stainless Steel 熔接部의 破壞擧動에 對한 硏究

金永奭,丁太權,朴昌彦,洪錫柱,梁仁榮,金基玉,朴煥奎,李茂錫,曺圭宰,鄭在康 조선대학교 생산기술연구소 1983 生産技術硏究 Vol.1983 No.-

This paper is based on an experiment analysing the stress corrosion cracking behaviour of welding specimens compared to that of non-welding specimens of STS 304 HP stainless steel in corrosion solution. As a corrosion condition, stainless steel has been known to be the most fragile in a solution of 42% MgCl₂heated to the boiling point, therefore the experiment was carried out in this condition. The experiment was carried out with argon gas TIG welding specimens and non-welding ones made of stainless steel plates, thickness 2mm, by tensile force. At this time, the tensile force was taken to be the value of the yield strength of the tensile test specimens divided by the safety factor of 3.0 to 3.5, 4.0, 4.5, and 5.0. In this paper, the relations between Time of Initial Crack, Time of Failure, Time of Final Fracture and Crack Propagation Length were investigated and then plotted. Furthermore, the relations between Stress Intensity Factor K proposed by Irwin and the Time of Initial Crack, the Time of Failure, the Time of Final Fracture were calculated and plotted. At the last, all the relations plotted were expressed to normal equations by computer, and the equations were used to analyse the data obtained in the experiment. The conclusions obtained in this study are as follows: 1. Welding materials, compared with non-welding ones, as the Time of Initial Crack, the Time of Failure, and the Time of Final Fracture were generally very fast, appeared to be a phenomenon of unstable brittleness fracture. 2. Non-welding materials, compared with welding ones, as the safety factor was larger or the working stress was smaller, appeared to be a phenomenon that the longer had had greater durability. Therefor, welding materials must be considered enough to be used in heate affected and stress corrosion atmosphere. 3. The normal equations of the Time of Initial Crack and the variation rate to the same Stress Intensity Factor K are as follows: (A) Non-welding T =259702.4-5451.2 K+28.386 K² T = -5451.2+28.386 K (B) Welding T= -332.693+28.043 K-0.211 K² T' =28.043-0.211 K here, T; Time of Initial Crack, T'; Variation Rate of Time of Initial Crack to Stress Intensity Factor K, K ; Stress Intensity Factor.

C-reactive protein accelerates DRP1-mediated mitochondrial fission by modulating ERK1/2-YAP signaling in cardiomyocytes

( Suyeon Jin ),( Chan Joo Lee ),( Gibbeum Lim ),( Sungha Park ),( Sang-hak Lee ),( Ji Hyung Chung ),( Jaewon Oh ),( Seok-min Kang ) 생화학분자생물학회 2023 BMB Reports Vol.56 No.12

C-reactive protein (CRP) is an inflammatory marker and risk factor for atherosclerosis and cardiovascular diseases. However, the mechanism through which CRP induces myocardial damage remains unclear. This study aimed to determine how CRP damages cardiomyocytes via the change of mitochondrial dynamics and whether survivin, an anti-apoptotic protein, exerts a cardioprotective effect in this process. We treated H9c2 cardiomyocytes with CRP and found increased intracellular ROS production and shortened mitochondrial length. CRP treatment phosphorylated ERK1/2 and promoted increased expression, phosphorylation, and translocation of DRP1, a mitochondrial fission-related protein, from the cytoplasm to the mitochondria. The expression of mitophagy proteins PINK1 and PARK2 was also increased by CRP. YAP, a transcriptional regulator of PINK1 and PARK2, was also increased by CRP. Knockdown of YAP prevented CRP-induced increases in DRP1, PINK1, and PARK2. Furthermore, CRP-induced changes in the expression of DRP1 and increases in YAP, PINK1, and PARK2 were inhibited by ERK1/2 inhibition, suggesting that ERK1/2 signaling is involved in CRP-induced mitochondrial fission. We treated H9c2 cardiomyocytes with a recombinant TAT-survivin protein before CRP treatment, which reduced CRP-induced ROS accumulation and reduced mitochondrial fission. CRP-induced activation of ERK1/2 and increases in the expression and activity of YAP and its downstream mitochondrial proteins were inhibited by TAT-survivin. This study shows that mitochondrial fission occurs during CRPinduced cardiomyocyte damage and that the ERK1/2-YAP axis is involved in this process, and identifies that survivin alters these mechanisms to prevent CRP-induced mitochondrial damage. [BMB Reports 2023; 56(12): 663-668]

Multiple myeloma 환자에서 Bortezomib치료 후 발생한 마비성 장폐색증 1례

김준영,이원식,손창학,박성길,진한영,박석주,조영완,정은욱,강명주,박정하,주영돈 인제대학교 2006 仁濟醫學 Vol.27 No.-

Bortezomib is the first clinically available proteasome inhibitor that is clinically effective in the treatment of multiple myeloma. A proteasome inhibitor acts through multiple mechanisms to arrest tumor growth, tumor spread, and angiogenesis. The main adverse effects of bortezomib are gastrointestinal symptoms, cytopenia, fatigue, and peripheral neuropathy. To date, severe paralytic ileus has not been reported as a toxic effect of bortezomib treatment in multiple myeloma. Bortezomib is a novel agent that has only been used clinically for 30 months, so a need exists to further evaluate its toxicity. We report a case of grade Ⅲ (NCI CTCAE v3.0) or grade Ⅳ(SWOG toxicity criteria) paralytic ileus in a 65-year-old man with relapsed multiple myeloma who underwent one cycle of single-agent bortezomib treatment scheduled in a 21-day cycle (1.3 mg/㎥ as a single i.v. bolus on days 1, 4, 8, and 11).

순음의 위상차를 이용한 스테레오 시스템에서의 음상 정위 특성 연구

박영민,박양우,장주석 경운대학교 산업기술연구소 2000 産業技術硏究論文誌 Vol.3 No.1(B)

In the AV system, stereophonic system has been studied to produce a realistic sound effect. The width of stereo AV system speakers is narrow, to have the spatial impression of sound effect, widening the sound image is necessary. The direction of sound image depends on the phase delay and the sound pressure level difference between two channels. In this paper, we analyze the relationship between the phase delay and the direction of the sound image relating to the frequency of sound source. Also we experimented to directionally localize the sound image of the pure tone with shifting phases and controling sound pressure level between two channels when the sound is reproduced by two speakers to make a spatial impression of sound effect.

연안 도시 대기오염 물질의 농도분포 특성

박종길,석경하,김지형,차주완 한국환경과학회 2002 한국환경과학회지 Vol.11 No.12

This paper aims to find the characteristics of concentration distribution of coastal urban air pollutants. For this purpose, It was used the daily meteorological data and hourly concentration data O_3 and NO_2 in Busan metropolitan city from 1994 to 1996. It was investigated the annual and monthly distribution of ozone and nitrogen dioxide concentration at each site in Busan, and also investigated the characteristics of concentration change of air pollutants with time under the sea breeze. As a results, the concentration of nitrogen dioxide and ozone tend to be increased every year and nitrogen dioxide concentration is higher than ozone concentration at all site in Busan. The concentration of ozone is high in summer season and low in winter season, but the concentration of nitrogen dioxide have a reversed trend. The monthly peak concentration of ozone occurred in April and September, while the monthly minimum concentration of nitrogen dioxide occurred in August. Their trend were indentified by sites near the coastline than sites stands apart from the coastline. The sea breeze occurred annual mean 81 days in Busan from 1994 to 1996. The main wind direction of sea breeze was classified into southeasterly. In case of southwesterly, It was pronounced the south wind and southwest wind. In case of southeasterly, the occurrence frequency of east wind was high. Especially, the concentration of urban air pollutants, such as ozone and nitrogen dioxide, were high on time which the sea breeze flow, and the areas that ozone concentration was high moved from outside part to central part of city with time. In costal urban such as Busan, the wind direction of sea breeze is influenced the influenced the change of ozone and nitrogen dioxide concentration on time which the sea breeze flow at each site and air pollutants concentration of sites on the pathway of sea breeze.

광대역 무선 가입자망(LMCS) 시스템의 상향스트림 처리를 위한 AIU(ATM Interface Unit)의 상향스트림 전송부 구현

박영민,박준호,장주석 경운대학교 산업기술연구소 2000 産業技術硏究論文誌 Vol.3 No.1(A)

Local Multi-point Communication System (LMCS) is a broadband wireless telecommunications common carrier service in the 28 GHz range that will be capable of carrying basic and advanced communication services as "wireless" cable TV, Internet access, video teleconferencing, and various other multimedia. Signals from a central transmitting/receiving station will be sent to and received from homes and businesses within a four to five kilometer radius. Several such stations will be required in each city to service the total geographic area. Homes and businesses will send and receive the signals through equipment consisting of a small, unobtrusive antenna plus the associated electronics, which are about the size of a television converter. To use wireless technology is world-wide trend. In this paper, we implemented a system to generate and transmit up-stream frame in the LMCS system based on ATM cell. This control circuit is designed in VHDL and implemented using AT& T ORCA FPGA 2C08-208 pin chips. It actually serves perfect image through the internet with 8Mbps. This FPGA chip operates upto 30MHz input clock frequency.

법랑모세포 분화와 법랑질 형성과정에서 OD314, Apin protein의 발현 및 기능

박종태,최용석,김흥중,정문진,오현주,신인철,박주철,손호현 대한치과보존학회 2006 Restorative Dentistry & Endodontics Vol.31 No.6

본 연구에서는 법랑모세포 분화와 법랑질 형성에 연관이 있는 OD314 일명 Apin protein의 기능을 밝힐 목적으로, in-situ hybridization에 의한 OD314 mRNA 발현과 법랑모세포 세포주에서 OD314 enamel matrix protein의 발현, 그리고 OD314 유전자를 과발현/억제시킬 수 있는 construct를 제작한 후 법랑질 형성 중에 OD314의 기능을 알아보고자 RT-PCR를 시행하여 다음과 같은 결과를 얻었다. 1. OD314 mRNA는 발생중인 상아모세포보다 법랑모세포에서 강하게 발현되었다. 2. Tuftelin은 석회화 결정이 형성되는 14일까지 발현이 지속되고, 그 이후부터 점차 감소하였다. Amelogenin과enamelin은 7일부터 그 발현이 점점 감소하였다. 3. U6-OD314 siRNA construct를 이용하여 transfection한 법랑모세포 세포주는 OD314와 tuftelin,MMP2 mRNA 발현이 감소하였으며, CM-OD314를 transfection하여 OD314의 과발현을 유도한 경우에는 OD314와 MMP20 mRNA의 발현이 뚜렷이 증대되었다. 이 결과는 OD314가 법랑모세포의 분화와 법랑질의 형성 그리고 석회화 과정에 중요한 역할을 하는 새로운 인자임을 시사한다. This study was aimed to elucidate the biological function of OD314 (Apin protein), which is related to ameloblast differentiation and amelogenesis. Apin protein, calcifying epithelial odontogenic (pindborg) tumors (CEOTs)-associated amyloid, were isolated from CEOTs, and has similar nucleotide sequences to OD314. We examined expression of the OD314 mRNA using in-situ hybridization during tooth development in mice. Expression of OD314 and several enamel matrix proteins were examined in the cultured ameloblast cell line up to 28 days by reverse transcription-polymerase chain reaction (RT-PCR) amplification. After inactivation and over-expression of the OD314 gene in ameloblast cell lines using U6 vector-driven RNA interference and CMV-OD314 construct, RT-PCR were performed to evaluate the effect of the OD314 during amelogenesis. The results were as follows: 1. In in-situ hybridization, OD314 mRNAs were more strongly expressed in ameloblast than odontoblast. 2. When ameloblast cells were cultured in the differentiation and mineralization medium for 28 days, the tuftelin mRNA expression was maintained from the beginning to day 14, and then gradually decreased to day 28. The expressions of amelogenin and enamelin were gradually decreased according to the ameloblast differentiation. 3. Inactivation of OD314 by U6-OD314 siRNA construct down-regulated the expression of OD314, MMP-20, and tuftelin, whereas over-expression of OD314 by CMV-OD314 construct up-regulated the expression of OD314 and MMP-20 without change in tuftelin. These results suggest that OD314 is considered as an ameloblast-enriched gene and may play the important roles in ameloblast differentiation and mineralization.

Effect of polydopamine‑modified reduced graphene oxides on the catalytic activity of Pt nanoparticles catalysts for fuel cell electrodes

Joo‑Hyoeng Woo,Soo‑Jin Park,Sungwook Chung,Seok Kim 한국탄소학회 2019 Carbon Letters Vol.29 No.1

We have studied a method to prepare polydopamine-modified reduced graphene oxide-supported Pt nanoparticles (Pt– PDA–RGO). The Pt–PDA–RGO nanocomposites were synthesized by a wet-coating process, which was induced by selfpolymerization of dopamine. As an eco-friendly and versatile adhesive source in nature, dopamine could be easily adhered to surfaces of organic material and inorganic material via polymerization processes and spontaneous adsorption under weak alkaline pH conditions. To apply the unique features of dopamine, we synthesized Pt–PDA–RGO nanocomposites with a different quantity of dopamine, which are expected to preserve the improved Pt adsorption on graphene, resulting in the enhanced electrocatalytic performance. The morphology and micro-structure were examined by field emission scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. Compared to pristine Pt–deposited RGO (Pt–RGO), Pt–PDA–RGO (30 wt% dopamine against RGO) nanocomposites showed a superior electrochemical active surface area for a methanol oxidation. This could be related to the fact that the optimized c

콘크리트 교량 및 강교의 상시감시 시스템에 관한 연구(Ⅰ)

박승범,홍석주,이봉춘 忠南大學校 産業技術硏究所 1998 산업기술연구논문집 Vol.13 No.1

The construction of large scale civil and building structures which form the base of social economy has been grown greatly. As the increasing of aged and deteriorated structure, it is necessary to evaluate the safety of those structures. The deterioration, safety evaluation repair and rehabilitation are important problems in the construction area that every country faces. This paper presents the general information on how to conduct a data analysis of long-term monitoring system and evaluate the characteristics of surveying methods.