논문 : 금속성 응집제와 모노클로라민의 상호작용이 Polyamide계 RO막 성능에 미치는 영향

김경화 ( Kyung Hwa Kim ),홍승관 ( Seung Kwan Hong ),박찬혁 ( Chan Hyuk Park ),윤성로 ( Seong Ro Yoon ),홍성표 ( Seong Pyuo Hong ),이종화 ( Jong Hwa Lee ) 대한상하수도학회 2006 상하수도학회지 Vol.20 No.4

The bench-scale chlorine exposure study was performed to investigate the effect of pretreatment by free chlorine and monochloramine (NH2Cl) on the performance of RO membranes made of polyamide (PA). Feed monochloramination at 2㎎/L did not cause significant productivity loss compared to free chlorine. However, metal coagulants reacted with monochloramine, the PA membrane suffered from a gradual loss of membrane integrity by chlorine oxidation, which was characterized as a decrease in salt rejection. Especially, RO membranes exposed to alum coagulants with monochloramine revealed the salt rejection lower than those exposed to iron coagulants. XPS membrane surface analysis demonstrated that the chlorine uptake on the membrane surface increased and carbon peaks were shifted significantly when exposed to alum coagulants with monochloramine.

2¼Cr-1Mo강 압력용기 용접이음부의 재열균열에 관한 역학적 연구

권영섭,노찬승,방한서 朝鮮大學校 機械技術硏究所 1999 機械技術硏究 Vol.2 No.2

구조물에 사용되는 각종 압력용기들의 재질은 고온 및 고압에 견딜 수 있도록 요구되고 있다. 따라서, 내열, 내압 및 내부식성이 뛰어난 2¼Cr-1Mo강의 수요가 향후 증대될 전망이다 용접잔류응력은 일반적으로 응접구조물에 각종 악영향을 미치는 것으로 알려져 있다. 이 때문에 용접잔류응력. 확산성 수소제거 및 용접 열영향부의 연화등을 목적으로 용접후열처리(PWHT)를 수행하나, PWHT를 행하면 사용 강재의 종류에 따라 재열균열이 발생하고 있다. 본 연구에서는 2¼Cr-1Mo강에 대하여 실험과 수치해석 기법을 통하여 용접이음부의 재열균열 감수성평가 및 상당크리프 변형율의 재열균열 발생에 판정에 대한 역학적 지표로서의 적용성을 검토하였다. 2¼Cr-1Mo steels are widely used to fabricate pressure vessels. Residual stresses, in general, are known to be harmful to the soundness of the welded structures. PWHT is release residual stresses, which may cause cracks. But, in those PWHT process, 2¼Cr-1Mo steels are apt to occur reheat crack frequently. In this reason, it is strongly needed to analysis and examine the mechanical behavior of welded joints through welding to PWHT process. So, in this study, welded nozzle parts of pressure vessel where reheat cracks are frequently occur are selected for examine the crack-occurrence mechanism.

위선암에서 장형화생의 변이형에 관한 연구

제갈승주,최영자,곽효일,노정섭,최찬 대한임상병리사협회 2001 대한임상병리사회지 Vol.21 No.1

Influence of Workpiece Tilting Angle on Joint Properties in Tailor Friction Stir Welded Blanks of Aluminium Alloy 5052-H32

Chan-Seung Ro,Hee-Seon Bang,Han-Sur Bang,Seung-Ji Yoo,Jong-Hee Kim,Eun-Gyeol Choi 대한용접·접합학회 2018 대한용접·접합학회지 Vol.36 No.5

The application of aluminium tailor-welded blanks (TWB) is progressively increasing in automotive industries due to its high strength to weight ratio, superior corrosion resistance and crashworthiness. The weldments produced by Friction stir welding (FSW) retains high strength and formability as the process yields the sound joints at relatively lower temperatures in comparison to that of the conventional fusion welding processes. However, the FSW of aluminium alloy of different thicknesses in butt configuration is rarely studied. The primary objective of the present work is to investigate the feasibility of FSW process in joining of 1.5 to 2.5 mm thick AA5052 alloy tailored blank by tilting the workpiece with respect to machine bed. The effects of workpiece tilting angle with welding and rotational speeds on mechanical and metallurgical properties of the joints are studied. Minimum effective sheet thickness is found to be around 1.34 mm for tool rotational speed of 400 rpm and tilting angle of 0°. The highest joint strength around 212.6 MPa (95% of base metal strength) is achieved at a workpiece tilt angle of 1° for rotational and travel speed of 400 rpm and 1 mm/s, respectively. The maximum measured hardness is 60 Hv at tool roational speed of 400 rpm with tilting angle of 1°.

적외선 열화상 카메라를 이용한 용접부의 온도 측정 방법

노찬승(Chan-Seung Ro),김경석(Kyeong-Suk Kim),장호섭(Ho-Seob Chang) 한국비파괴검사학회 2014 한국비파괴검사학회지 Vol.34 No.4

본 연구에서는 적외선 열화상 카메라와 열원 사이에 유리를 설치하여 측정기기의 보호 및 온도 보정을 통하여 고온의 용접부 온도를 실시간으로 측정하고자 하였다. 먼저 할로겐램프의 열에 대한 온도 차이를 실시간으로 촬영하고 온도를 측정한 결과, 카메라와 열원 사이의 거리별 온도는 거의 동일하게 측정되었음을 확인할 수 있었고, 유리 두께와 측정 거리의 상관관계를 통하여 온도 범위를 예측할 수 있다는 것을 알 수 있었다. 이를 바탕으로 용접열원에 대한 실험을 수행하여 열화상 카메라를 이용한 용접부의 온도 측정의 타당성을 제시하였다. In this paper, a method is tested to measure temperatures in high-temperature welds. Protective glass was installed between an infrared thermal imaging camera and a heat source, and temperature compensation was applied to the measuring instruments. When the temperature of halogen lamps was taken in real-time and measured by the thermal camera, the temperature was found to be almost invariant with the distance between the camera and heat source. The temperature range could be predicted, through correlations with the thickness of the protective glass and the measured distance. This study suggests that the temperature measurement of welds obtained by using an infrared thermal imaging camera is valid, through experimental testing of heat sources.

극후판 Box-Column의 Lamellar 균열 감수성 평가

노찬승(CHAN-SEUNG RO),박창수(CHANG-SOO PARK),김흥주(HEUNG-JU KIM),방한서(HAN-SUR BANG),이창우(CHANG-WOO LEE) 한국해양공학회 2003 韓國海洋工學會誌 Vol.17 No.4

In case of the thick rolling-steel for a multistory building, a large oil-drilling structure, a large vessel, a bridge and so on, Lamella Tearing around the welded joint zone is the one of the most serious problems. In order to prevent Lamella Tearing, not only is choice of material important, but also the comprehensive investigation for the structural design and the construction. The Lamella Tearing that is a staircase-shape occurs due to the contraction stress to the thickness direction of the plate and has the character that the cracks progress along the elongated inclusion by rolling. In general, because cracks occur at the heat affected zone and around HAZ, it is necessary to establish the safety and the confidence of the welded structure to restrain the welding defect such as Lamella Tearing. The mechanical approaches are the easier and more economical than the approaches of the material and the construction method. In addition, the appropriate welding profile and the optimum welding condition contribute toward the improvement of the productivity and influence on the standardization of the manufacturing technology.

금속분말재료의 사출 성형해석에 관한 연구

노찬승(Chan-Seung Ro),박종남(Jong-Nam Park),정한별(Han-Byul Jung) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.10

본 연구는 광통신용 아답타의 필수품인 플랜지 개발을 위한 금속분말 사출성형해석에 관한 내용이다. 금속분말 사출성형법은 세라믹 또는 스테인레스 분말과 바인더를 혼합하여 복잡한 형상의 사출성형품을 제조하는 기술로써, 지금까지 가공기술로 제작이 복잡하거나 생산성이 저조한 제품들에 대한 생산을 대체 할 수 있는 기술로 관심을 받고 있다. 연구 목적은 기존의 기계가공을 통해 제작했던 제품에 대해 공정을 최소화하기 위함이다. 사출성형해석을 위해 먼저 스테인레스 계 STS316 금속분말과 바인더를 6대4 비율로 혼합하여 과립형 펠렛의 사출 성형재료를 완성하여 해결하였다. 이후, 3차원 모델링, 모델의 메시화 작업 등을 수행하여 최적의 사출성형 해석조건(금형 온도, 용융 온도, 사출 시간, 사출 온도, 사출 압력, 충진 시간 및 냉각 시간 등)을 도출하였다. 해석결과 성형품은 최초 사출 후 13.29초가 경과되면 취출이 가능하였다. 또한 용융수지는 스프루, 러너, 게이트를 거쳐 금형 내부까지 유동 및 충전이 안정적으로 진행되어 양호한 성형품의 제조가 기대되었다. In this study,we conducted an injection molding analysis of metal powder materials for the development of flanges, which are necessary adapters for optical communication. The metal powder injection molding process is a technique for producing an injection molded article having a complicated shape by mixing ceramic or stainless powder and binders. It is used to produce products which require complex processing technology or for which the productivity is low. The purpose of this study is to minimize the manufacturing processing of products which aremanufactured through existing mechanical processing procedures. For the injection molding analysis, we mixed stainless STS316 metal powder with binders at a ratio of 6 to 4 to make molding materials consisting of granular pellets. Then, three-dimensional modeling and meshing were carried out to obtain the optimal injection molding analysis conditions(molding temperature, melting temperature, injection time, injection temperature, injection pressure, packing time and cooling time). As a result of the analysis, it was discovered that the inlet became available 13.29 seconds after the first injection. Also, as the flowing and packing in the melt through the sprue, runner and gate were stable, it is expected that good molds canbe manufactured.

Serum Response Factor Is Essential for Prenatal Gastrointestinal Smooth Muscle Development and Maintenance of Differentiated Phenotype

( Chan Jae Park ),( Moon Young Lee ),( Paul J Park ),( Se Eun Ha ),( Robyn M Berent ),( Robert Fuchs ),( Joseph M Miano ),( Laren S Becker ),( Kenton M Sanders ),( Seung Il Ro ) 대한소화기기능성질환·운동학회 2015 Journal of Neurogastroenterology and Motility (JNM Vol.21 No.4

Background/Aims Smooth muscle cells (SMCs) characteristically express serum response factor (SRF), which regulates their development. The role of SRF in SMC plasticity in the pathophysiological conditions of gastrointestinal (GI) tract is less characterized. Methods We generated SMC-specific Srf knockout mice and characterized the prenatally lethal phenotype using ultrasound biomicroscopy and histological analysis. We used small bowel partial obstruction surgeries and primary cell culture using cell-specific enhanced green fluorescent protein (EGFP) mouse lines to study phenotypic and molecular changes of SMCs by immunofluorescence, Western blotting, and quantitative polymerase chain reaction. Finally we examined SRF change in human rectalprolapse tissue by immunofluorescence. Results Congenital SMC-specific Srf knockout mice died before birth and displayed severe GI and cardiac defects. Partial obstruction resulted in an overall increase in SRF protein expression. However, individual SMCs appeared to gradually lose SRF in the hypertrophic muscle. Cells expressing low levels of SRF also expressed low levels of platelet-derived growth factor receptor alpha (PDGFRalow) and Ki67. SMCs grown in culture recaptured the phenotypic switch from differentiated SMCs to proliferative PDGFRalow cells. The immediate and dramatic reduction of Srf and Myh11 mRNA expression confirmed the phenotypic change. Human rectal prolapse tissue also demonstrated significant loss of SRF expression. Conclusions SRF expression in SMCs is essential for prenatal development of the GI tract and heart. Following partial obstruction, SMCs down-regulate SRF to transition into proliferative PDGFRalow cells that may represent a phenotype responsible for their plasticity. These findings demonstrate that SRF also plays a critical role in the remodeling process following GI injury. (J Neurogastroenterol Motil 2015;21:589-602)

TDI로 유발된 비과민성 기니픽에서 유발성 산화질소합성효소의 발현과 스테로이드의 영향

이승균,강준명,조진희,류찬,원유성,윤희로 대한이비인후과학회 2000 대한이비인후과학회지 두경부외과학 Vol.43 No.6

볼스크류의 축-비틀림 복합강성을 고려한 이송계 모델링

이찬홍(Chan Hong Lee),박천홍(Chun Hong Park),노승국(Seung Kook Ro),이후상(Husang Lee) 한국정밀공학회 2002 한국정밀공학회 학술발표대회 논문집 Vol.2002 No.5월