Effects of Pilger Rolling and Heat Treatment on Microstructure and Corrosion Resistance of Ag-electroplated 304 Stainless Steel Tubes

Hyun Park,Woo‑Jin Lee,Jae‑Han Son,Han‑Kyun Shin,Sung‑Kyu Hong,Hyo‑Jong Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

We introduce a cost-effective method that combines electroplating with metal cold working processes to manufacture compositetubes with robust corrosion resistance. First, a 3-step electroplating process was developed to form an adhesive anduniform Ag coating on the outer wall of a 304 stainless steel tube. The process consisted of a Ni-strike step for removing thepassivation layer of the initial 304 tube, Cu deposition for smoothing the surface by adding a buffer layer, and Ag deposition. To reinforce the interfacial adhesion between the electroplated layers and the 304 tube and increase the area of the Ag coating,a pilger rolling or pilger rolling + heat-treatment process was performed after the Ag electroplating process. Scanningelectron microscopy of the composite tubes after each process indicated that the as-deposited Ag coating changed fromhaving a rough to smooth surface after only pilger rolling and with additional heat treatment. Electron backscatter diffractionanalysis of the microstructures and textures of the tubes revealed that dynamic recrystallization occurred extensively duringpilger rolling, resulting in the formation of a relatively defect-free grain structure without heat treatment. Furthermore,electrochemical polarization curves determined that the Ag-coated composite tubes are superior to the uncoated 304 tubein terms of corrosion resistance under Cl−atmosphere, owing to the formation of a AgCl passivation layer during testing. Surface analysis of the composite tubes suggests that the properties of the AgCl passivation layer are related to the grainsize of the Ag coating and the density of plastic-deformation-induced defects.

골격성 Ⅲ 급 부정교합자의 두개안모 성장예측에 대한 평가

손우성,강은희,정미라,성지현 대한치과교정학회 2003 대한치과교정학회지 Vol.33 No.1

본 연구는 성장에 의한 변화를 예측하는 현재의 방법이 실제로 골격성 Ⅲ급 부정교합자의 진단과 치료계획에 적절히 사용될 수 있는 지를 판단해 보기 위해 초진 시 골격성 Ⅲ급 부정교합으로 진단받고 성장 종료 후 악교정 수술을 받기위해 재내원한 골격성 Ⅲ 급 부정교합자 25명(남자 13명, 여자 12명)을 대상으로 시행되었다. 초진시 채득된 측모 두부방사선 사진에서 Ricketts의 성장예측법을 통해 성장 종료 후의 상태를 예측한 후, 악교정 수술을 위해 재내원 했을 때 채득된 측모 두부방사선 사진에서 계측된 실제 성장량과 비교분석 함으로써 다음과 같은 결론을 얻었다. 1. 예측치와 관측치의 일치정도를 평가해본 결과 Porion Location, Ramus Position, Facial Depth, Facial Axis, Mandibular Plane angle, Maxillary Convexity에서의 예측치가 관측치와 차이를 보이고 있어 이 항목에 대한 Ricketts 성장예측법의 예측치가 실제 성장량을 잘 설명해주지 못함이 관찰되었다. 2. 하악골체의 성장량은 정상 성장량과 유사하였으나 Porion Location, Ramus Position이 정상적인 성장과정을 벗어나면서 하악골의 전방위치를 유도하였다. 3. 골격성 Ⅲ 급 부정교합자에서는 성장의 양과 방향이 비정상적인 성장변화를 나타내어 정상 성장에서라면 변화를 보이지 않을 하악지의 전방 위치, 하악이부의 전상방 회전 등이 일어난 하악 전돌의 경향이 악화될 수 있다. This study was performed to evaluate whether growth prediction method can be used to diagnose and make treatment plan in skeletal Class Ⅲ malocclusion patients or not. The sample was consisted of 25 patients(13 males, 12 females) who had been diagnosed with skeletal Class Ⅲ malocclusion at first visit and after that had returned to take orthognathic surgery. Growth prediction performed with Ricketts' growth prediction method from first cephalogram was compared with actual growth of the second cephalogram. The findings of this study were as follows ; 1. There was significant difference between actual growth and growth prediction in Porion Location, Ramus Position, Facial Depth, Facial Axis, Mandibular Plane angle, Maxillary Convexity. So, for these items Ricketts' growth prediction method is not proper to predict growth. 2. Although the growth amount of mandibular body was similar to normal growth amount, mandible was positioned anteriorly because of Porion Location and Ramus Position. 3. In skeletal Class Ⅲ malocclusion patients, the tendency of mandibular prognathism might be aggreviated because of anterior placement of ramus and anterosuperior rotation of pogonion.

가스누출 감지용 실리콘 압저항형 절대압센서의 제조 및 온도보상

손승현,이재곤,김우정,최시영 경북대학교 센서기술연구소 1997 센서技術學術大會論文集 Vol.8 No.1

Silicon piezoresistive absolute pressure sensor for gas leakage alarm system was developed. This sensor must operate normally in the range of 0-600 mmH_(2)O for pressure, 0-100 ℃ for temperature. To make the most of this sensor for gas leakage alarm system, gas must not leak from sensor itself when sensor-diaphragm fractures. Thus the sealed diaphragm cavity was anodically bonded to pyrex 7740 glass under the condition of ~2 mtorr, at 400 °C. The sensitivity of developed sensor was 4.06 μV/VmmH_(2)O for 600 mmH_(2)O full-scale pressure range. And temperature compensation method of this sensor is to change bridge-input-voltage linearly in proportion to the temperature variation. By this method the temperature effect in the range of 0-100 C was compensated over 90 %.

체육교사의 정신지체학생 지도유형에 대한 하위구조의 신뢰성과 타당성 검증

이현수,이근모,손승우 釜山大學校 附設 體育科學硏究所 2005 體育科學硏究所 論文集 Vol.21 No.2

The purpose of this study was to reliability and validity of the substructure about physical education teachers teaching types to Students with Mental Retradation. The study used to 241 middle school students(male:118, female:123) as subjects for actual analysis with the purposive sampling, except insincere 11 samples......

방사선에 의해 제조된 pH 및 온도에 민감한 수화겔의 물성연구 및 약물방출에 관한 연구

김현우,노영창,손태일 한국공업화학회 2003 공업화학 Vol.14 No.3

N-isopropylacrylamide (NIPAAm)와 acrylic acid (AA)를 증류수에 일정한 몰비로 용해한 것과 여기에 butyl acrylate (BA)를 혼합한 용액을 상온에서 30, 50 kGy로 γ-선 조사하여 중합반응과 가교를 동시에 일으켜 pH 및 온도에 민감한 수화겔을 제조하였다. 제조된 수화겔은 pH 2, 7의 용액에서 5~40℃로 온도를 변화시켜 각각의 온도에서 최대 팽윤도를 측정하고 한편으로는 37℃로 고정한 후 PH 2~8까지 pH에 대한 최대 팽윤도를 측정하였다. 수화겔의 팽윤과 수축에 이온강도가 어떤 영향을 미치는지 알아보기 위해 0, 0.01, 0.03 N의 염화나트륨 용액에서 팽윤실험을 하였다. 경구용 인슐린 전달제재를 제조할 목적으로 수화겔이 최대 팽윤할 수 있는 최저의 온도와 pH 조건에서 인슐린을 탑재한 다음 자연건조(air dried)와 동결건조(freeze dried)를 하여 인슐린을 함유한 겔(drug-gels)을 제조하였으며, 인슐린 탑재 후 남은 인슐린 용액으로부터 탑재효율을 구하였다. Drug-gel은 in vitro에서 인공위액(simulated gastric fluid; SGF)과 인공장액(simulated intestinal fluid ; SIF)에서 약물 방출량을 측정하여 방출속도를 측정하였다. Temperature and pH sensitive N-isopropyacrylamide-acrylic acid (NIPAAm-AA) and N-isopropylacrylamide-acrylic acid-butyl acrylate (NIPAAm-AA-BA) hydrogels were synthesized by simultaneous polymerization and crosslinking of NIPAAm AA, and BA monomers in aqueous solution using γ-rays from ^60Co source at room temperature. The measurements of equilibrium water content on the synthesized hydrogels were made at the temperature ranging from 5 to 40℃ and pH 2 and 7. The prepared hydrogels had temperature-sensitive (30~35℃) and pH-sensitive swelling behavior. The HIPAAm-AA and NIPAAm-AA-BA hydrogels were used in drug delivery systems for the controlled release of insulin Insulin has been shown to have binding sites for hydrophobic molecules. Thus, it is likely that insulin binds specifically to the butyl side. The gels including insulin were prepared by air drying or freeze drying after loading insulin in solution (14.1 IU/mL) at 5℃ and pH 7. Drug-gels were plated in simulated gastric fluid (SGF; pH 1.2) at 37℃ for 2 h and then at simulated intestinal fluid (SIF : pH 7.3). The insulin release of the drug-gels was examined by UY analysis.

골격성 Ⅲ급 부정교합자에서 상악골 전진술을 동반한 양악 수술 시 중안면 연조직 형태의 변화

정종현,김성식,손우성,박수병 대한치과교정학회 2008 대한치과교정학회지 Vol.38 No.2

본 연구는 중안면 함몰이 있는 골격성 III급 부정교합자의 중안면의 형태를 정상 표본과 비교하고, 악교정수술에 의하여 연조직이 어떤 변화를 보이는지를 알아보기 위하여 시행하였다. 골격성 III급 부정교합으로 진단받고 상악 전진술과 하악 후퇴술을 시행받은 환자 34명 (남자:15명, 여자:19명)을 대상으로 수술 전후 측모 두부방사선 계측사진을 분석하였다. 골격성 III급 부정교합자의 중안면의 경조직 계측치 S'-Or, Or⊥NA, S'Or/SN, ∠SNOr에서 남녀 모두에서 정상 교합자와 큰 차이가 있었다. 상악골이 평균 5.03 mm 전방이동 될 때 연조직 Orbitale는 2.26 mm 전방으로 이동하였으며 상관계수는 0.599였다(p < 0.05). 상악 평면각의 변화(시계방향으로 회전)와 상악골의 수직 이동은 연조직 Orbitale의 전방이동과 유의성있는 상관관계가 없었다. 상악골 전방이동에 대한 연조직 Orbitale와 Subnasale의 전방이동 비율은 각각 43.57%, 81.54%였다. 이상의 결과에서 중안면 함몰이 있는 환자는 상악골 전방이동시 상순과 비부 외에도 연조직 Orbitale를 포함한 중안면 연조직이 전방으로 이동하지만, 상악골의 회전이동 및 수직이동에 대해서는 연조직의 변화량이 적었다는 것을 알 수 있었다. 이는 상악골의 수술에 따른 중안면 함몰의 해소를 예측하는 데 도움이 될 것이다. Purpose: The first objective of this study was to compare the upper midface morpholgy, focusing on the soft tissues, between skeletal Class III maloccusion patients with midfacial depression and the norm. The second objective was to estimate and analyze the change in the upper midface soft tissues following surgical correction with maxillary advancement by Lefort I osteotomy and mandibular setback by bilateral sagittal split osteotomy (BSSRO). Methods: The samples consisted of 34 adult patients (15 males and 12 females) with an average age of 21 years, who had severe anteroposterior discrepancy with midfacial depression. These patients had received presurgical orthodontic treatment and surgical treatment which consisted of simultaneous Lefort I osteotomy and BSSRO. Results: The correlation coefficient between changes in maxillary advancement and changes in Or' (soft tissue orbitale) was 0.599 (P < 0.05). Change in maxillary plane angle and vertical change of the maxilla were not correlated with the change in Or' (P < 0.05). The ratio of soft tissue change in Or' to maxillary advancement was 43.57 %, and 81.54 % in Sn. Regression equations between maxillary movement and Or' were devised. The r² value was 0.476. Conclusions: The majority of measurements in the upper midface in skeletal Class III maloccusions when compared to the norm, showed significant differences. In Class III malocclusion with midfacial depression, maxillary advancement produces soft tissue change in the upper midface.

지능형 원격 네트워크 온실

문병현,송주열,이현성,손경규,엄태환,김정우,김아름 대구대학교 정보통신연구소 2004 情報通信硏究 Vol.3 No.2

The system designed in this paper, can mark the interior state of greenhouse using sensors of temperature, humidity and illumination on greenhouse interior by greenhouse system for farm village area's agriculture automation. And, the real time monitor is possible real time monitoring by camera. Also, system that can supply water using spring cooler system and humidifier. The proposed system can sustain a designed environment of the greenhouse through rentilation fan, fluorescent light and roof door control. TCP/IP is used for the remote control of state the sensors in the client program. 본 논문에서 설계된 시스템은 농촌 지역의 농업 자동화를 위한 온실 시스템으로 온실 내부에 온도, 습도, 조도 센서를 이용한 온실 내부의 상태를 표시할 수 있으며 카메라를 이용하여 실시간 관측이 가능하다. 또한 본 시스템은 지붕 개폐, 스프링 쿨러와 가습기를 이용한 수분 공급, 환풍기, 형광등 등을 통하여 온실 내부의 환경을 유지시킬 수 있다. 모든 센서를 이용한 상태와 온실 제어를 TCP/IP를 이용한 클라이언트 프로그램에서 원격으로 관리할 수 있다.

골격성 Ⅲ 급 부정교합자의 악골 부조화가 구치부 치성보상에 미치는 영향

성지현,김성식,손우성 대한치과교정학회 2003 대한치과교정학회지 Vol.33 No.1

골격성 Ⅲ 급 부정교합자는 부적절한 악골 위치에서 기능 교합을 유지하기 위해 치아의 경사도와 수직적 위치가 변화하게 된다. 이러한 치성보상은 전치부 및 구치부 전반에 걸쳐 일어나며, 현재 보편적으로 시행되고 있는 악교정수술을 위한 술전교정시 이를 제거하여 각 골격 구조내에서 치아들이 적절히 위치되도록 하여야 한다. 전치부 치성보상에 관한 측모 두부방사선 사진을 이용한 연구는 많이 시행되어졌으나, 구치부 경사도에 관한 연구는 미미한 실정이다. 이에 본 연구는 성인 골격성 Ⅲ 급 부정교합자의 전후방적, 수직적 악골 부조화에 따른 폭경 부조화 및 구치 경사도 변화를 알아보기 위해 진단 모형상에서 상하악 견치, 제1소구치, 제1대구치 부위의 기저골 폭경을 측정하여 상악에 대한 하악의 비율을 구하였으며, 모형을 삭제하여 좌우 구치간 경사도를 측정하였다. 악골 부조화 심화에 따른 기저골 폭경 비율과 제1대구치 협설 경사도 변화의 상관관계를 조사하여 다음과 같은 결론을 얻었다. 1. 골격성 Ⅲ 급 부정교합자의 악공의 전후방적 부조화가 심화될수록 상하악 구치간 각도합이 증가하여 치성보상이 많이 일어났으며, 특히 하악 구치가 설측 경사되는 치성보상을 보였다(p<0.001). 2. 골격성 Ⅲ 급 부정교합자의 악골의 수직적 부조화 및 폭경 부조화와 구치부 치성부상 간에는 유의할만한 상관성이 없었다. 3. 골격성 Ⅲ 급 부정교합자의 전후방적, 수직적 부조화의 심화와 기저골 폭경 부조화는 유의할만한 상관성이 없었다. This study examined the relations between degree of posterior dental compensation and skeletal discrepancy in Class Ⅲ malocclusion. The pretreatment lateral cephalograms and dental casts of 87 skeletal Class Ⅲ adults were selected to provide a random sampling of skeletal Class Ⅲ malocclusion. Skeletal discrepancy was described with ANB angle, Wits appraisal, Sn-Mn plane angle, FMA and ratios of basal arch width. Degree of posterior dental compensation was described with macillary intermolar angle, mandibular intermolar angle and sum of intermoloar angle. The relationships between skeletal discrepancy and degree of posterior dental compensation were analyzed with simple correlation analysis, stepwise multiple regression analysis. The results were as follows : 1. A strong association was found between the variation in the anteroposterior measure, ANB angle and the variation of posterior dental compensation measures, sum of intermolar angle and mandibular angle and mandibular intermolar angle in skeletal Class Ⅲ malocclusion. 2. There was no statistically significant relationship between the variation in the vertical measures and the variation of posterior dental compensation measures in skeletal Class Ⅲ malocclusion. 3. There was no statistically significant relationship between the variation in the anteroposterior and vertical measures and degree of basal arch width discrepancy.

이염화이소시아뉼산나트륨 제재의 근관세척액 사용 가능성 평가 : 염소이온농도, 세포독성, 항균성 및 pH

이우철,강봉선,김철호,손호현 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.5

The purpose of this study was to evaluate the clinical applications of the Sodium Dichloroisocyanurate effervescent tablet as a routine root canal irrigant by performing several in vitro tests such as CI content. cytotoxicity. antimicrobial effect as well as its pH level compared to the equivalent concentration of sodium hypochlorite solution. 1. Sodium Dichloroisocyanurate demonstrated lower level of CI concentration than each dilution of sodium hypochlorite solution. Both solution has increased level of CI as the concentration of each solution increased. There was no significant change of CI concentration in sodium hypochlorite as time goes by. However. CI concentration in Sodium Dichloroisocyanurate was increased. 2. The antimicrobial effects of both solutions were increased when their concentrations were increased. One day after dilution. antimicrobial effect of Sodium Dichloroisocyanurate was slightly higher than sodium hypochlorite. however. there was no difference in 1 week dilution solution. One month dilution solution of sodium hypochlorite still retain its activity. but antimicrobial effect of Sodium Dichloroisocyanurate was drastically decreased 1 month after dilution. 3. The cytotoxicity of Sodium Dichloroisocyanurate was rather higher than same concentration of sodium hypochlorite solution until 1 week after dilution. Then in 1 month. cytotoxicity of Sodium Dichloroisocyanurate was decreased than that of 1 week dilution solution. especially 4% Sodium Dichloroisocyanurate solution has almost no toxicity. However. 1% and 2% sodium hypochlorite solution has unchanged moderate degree of cytotoxicity after the dilution. Furthermore. 4% sodium hypochlorite solution showed high level of toxicity. 4. The pH level of Sodium Dichloroisocyanurate showed that the solution was weak acid (pH5). On the other hand. sodium hypochlorite was revealed as a strong alkaline solution (pH12). There was no change in pH following the dilution of each solution. As results. Sodium Dichloroisocyanurate solution fully satisfy the basic requirements as a root canal irrigation solution. However. we strongly recommend to use this solution clinically in low concentration and try to apply into the root canal within 1 week after dilution.

의료 질 향상 사업의 성공요인과 실패요인

최귀선,이선희,조우현,강혜영,채유미 한국의료QA학회 2001 한국의료질향상학회지 Vol.8 No.2

Background : To propose effective strategies for successful implementation of QI in health care institutions, by identifying facilitating factors and barriers to conducting QI programs. Methods : In order to examine empirical evidence on the success factors or barriers to QI implementation in hospitals, a literature study was performed on the basis of MEDLINE search. Among the identified literature. 13 provided reliable findings and basis comprehensive discussion on this issue and thus were selected for in-depth analysis. A mailed questionnaire survey was conducted for hospital CEOs and QI directors of hospitals with 400 beds or greater to investigate what attributes of their organizations they perceived as success factors or obstacles to QI implementation. Result : The analysis of selected literature and survey results presented that the primary factors considered to be most important as successful implementation of QI were: strong support from hospital CEOs, setting higher priority for QI activities, continuous and persistent efforts in QI activities, and active participation of clinical staffs. The barriers identified in this study were : the lack of orientation and understanding of QI concepts, low level of interest and participation of physician in QI programs, the lack of evaluation and rewarding system for QI activities. Conclusion : By identifying factors that affect facilitation of QI, the study results will be of great use for either institutions being in the early stage of evolving QI or those looking for better strategies to achieve more active and persistent QI implementation in their institutions.