• 제목/요약/키워드: Filling Process

검색결과 896건 처리시간 0.024초

Surface-modified Nanoparticle Additives for Wear Resistant Water-based Coatings for Galvanized Steel Plates

  • Becker-Willinger, Carsten;Heppe, Gisela;Opsoelder, Michael;Veith, H.C. Michael;Cho, Jae-Dong;Lee, Jae-Ryung
    • Corrosion Science and Technology
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    • 제9권4호
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    • pp.147-152
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    • 2010
  • Conventional paints for conversion coating applications in steel production derived mainly from water-based polymer dispersions containing several additives actually show good general performance, but suffer from poor scratch and abrasion resistance during use. The reason for this is because the relatively soft organic binder matrix dominates the mechanical surface properties. In order to maintain the high quality and decorative function of coated steel sheets, the mechanical performance of the surface needs to be improved significantly. In fact the wear resistance should be enhanced without affecting the optical appearance of the coatings by using appropriate nanoparticulate additives. In this direction, nanocomposite coating compositions (Nanomer$^{(R)}$) have been derived from water-based polymer dispersions with an increasing amount of surface-modified nanoparticles in aqueous dispersion in order to monitor the effect of degree of filling with rigid nanoparticles. The surface of nanoparticles has been modified for optimum compatibility with the polymer matrix in order to achieve homogeneous nanoparticle dispersion over the matrix. This approach has been extended in such a way that a more expanded hybrid network has been condensed on the nanoparticle surface by a hydrolytic condensation reaction in addition to the quasi-monolayer type small molecular surface modification. It was expected that this additional modification will lead to more intensive cross-linking in coating systems resulting in further improved scratch-resistance compared to simple addition of nanoparticles with quasi-monolayer surface modification. The resulting compositions have been coated on zinc-galvanized steel and cured. The wear resistance and the corrosion protection of the modified coating systems have been tested in dependence on the compositional change, the type of surface modification as well as the mixing conditions with different shear forces. It has been found out that for loading levels up to 50 wt.-% nanoparticles, the mechanical wear resistance remains almost unaffected compared to the unmodified resin. In addition, the corrosion resistance remained unaffected even after $180^{\circ}$ bending test showing that the flexibility of coating was not decreased by nanoparticle addition. Electron microscopy showed that the inorganic nanoparticles do not penetrate into the organic resin droplets during the mixing process but rather formed agglomerates outside the polymer droplet phase resulting in quite moderate cross linking while curing, because of viscosity. The proposed mechanisms of composite formation and cross linking could explain the poor effect regarding improvement of mechanical wear resistance and help to set up new synthesis strategies for improved nanocomposite morphologies, which should provide increased wear resistance.

SBR에서 아세트산 주입시간변화에 따른 양돈폐수의 질소, 인 제거특성 (Removal Character of Nitrogen and Phosphorus in Swine Wastewater with Injection Time of Acetic Acid on SBR)

  • 허목;이용두;강진영
    • 유기물자원화
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    • 제11권1호
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    • pp.132-137
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    • 2003
  • 본 연구는 생물학적처리공정인 SBR에서 아세트산의 주입시간에 따른 질소와 인의 제거특성을 알아보기 위해서 수행되었으며, 실험기간동안 사용된 폐수는 유기물에 비해 질고농도가 상대적으로 높은 특성을 갖는 양돈폐수이었다. 아세트산의 주입시간에 따른 실험에서 Run 1은 무산소기간에 아세트산을 주입하지 않았고, Run 2는 무산소기간 15시간동안 간헐적으로 아세트산을 주입하였다. 그리고 Run 3은 폐수유입의 종료시로부터 3시간의 무산소기간동안에 간헐적으로 주입하였다. 그리고 폐수의 유입시간은 모든 조건에서 20시간으로 하였다. 본 실험에서 유기물과 질소에 있어서 가장 제거효율이 높게 나타난 조건은 Run2(교반/폭기 시간비 : 16.5/5.5, 아세트산주입시간 15시간)이었고, T-P에 있어서는 Run 3조건(교반/폭기 시간비 : 16.5/5.5, 아세트산주입시간 : 3시간)에서 가장 높은 효율을 나타내었으며 각각의 제거효율은 $BOD_5$ 96.1%, $COD_{Mn}$ 87.7%, $COD_{Cr}$ 90.6%, T-N 86.6% 그리고 T-P는 84.5%로 나타내었다.

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발포고분자여재가 충전된 파일럿 규모의 비점오염물질 처리장치를 이용한 도로 강우유출수 처리 (Road Runoff Treatment using Pilot Scale-NPS Treatment Plant Filling up Expended Polypropylene Media)

  • 김석구;오혜철;안재환
    • 대한환경공학회지
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    • 제36권10호
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    • pp.711-718
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    • 2014
  • 실제 도로현장에 Pilot plant 규모의 비점오염물질 처리장치를 적용하여 강우사상에 따른 유출과 각 오염물질에 대한 처리특성을 조사하였다. 발포고분자 여재를 충전시킨 여과컬럼은 90분 이후에 막힘 현상이 발생되어 유입수의 bypass 현상이 발생되었다. SS 200 mg/L 이상의 고농도가 처리조로 유입될 경우 반응시간 60분부터 유출수의 처리효율이 급격히 저하되었다. 고형물질 농도(SS) 180 mg/L 이하에서는 안정적인 처리가 이루어졌다. $COD_{Cr}/SS$ 비는 중간값 0.67로 분석되었으며, SS의 제거는 $COD_{Cr}$의 제거와 밀접하게 나타났다. SS와 $COD_{Cr}$의 평균 제거율은 각각 92.1%와 82.3%로 나타났다. 유입수의 TP 농도가 0.5 mg/L 이하일 경우 처리수질이 0.1 mg/L 수준에서 안정적인 처리를 나타내었고, 1.0 mg/L 이상으로 유입될 경우 처리수의 수질은 평균 0.2 mg/L를 초과였다. TN의 경우 4~10 mg/L로 반응조로 유입될 경우 처리수질은 1.5~3.0 mg/L 수준을 유지하였다. TP와 TN 각각의 평균제거율은 73.9%, 50.4%이다.

주조용 Al-4wt%Mg-0.9wt%Si-0.3wt%Mn-0.15wt%Fe 합금의 공정 Mg2Si 개량과 주조특성에 미치는 Sc, Sr 첨가원소의 영향 (Effect of Sc, Sr Elements on Eutectic Mg2Si Modification and Castability of Al-4wt%Mg-0.9wt%Si-0.3wt%Mn-0.15wt%Fe Casting Alloy)

  • 김헌주
    • 한국주조공학회지
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    • 제35권6호
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    • pp.147-154
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    • 2015
  • The effects of Sc and Sr elements on the modification of the eutectic $Mg_2Si$ phase and the castability were investigated in the Al-4wt%Mg-0.9wt%Si-0.3wt%Mn-0.15wt%Fe alloy. Measurements of the cooling curve and microstructure observations were performed to analyze the additional effects of Sc and Sr minor elements during the solidification process. A prominent effect found on the modification of the eutectic $Mg_2Si$ phase with additions of the Sr and Sc elements. Here, a fine eutectic $Mg_2Si$ phase and a decrease in the growth temperature of the eutectic $Mg_2Si$ phase were evident with an addition of Sc element up to 0.2 wt%. The growth temperature of the eutectic $Mg_2Si$ phase decreased and the effect on the modification of the eutectic $Mg_2Si$ phase increased with the addition of Sr element up to 0.02 wt%. The addition of 0.02wt%Sr had the strongest effect on the modification of the eutectic $Mg_2Si$ phase, and the resulting microstructure of the eutectic $Mg_2Si$ phase was found to have a fibrous morphology with a decreased aspect ratio and an increased modification ratio. Fluidity and shrinkage tests were conducted to evaluate the castability of the alloy. The addition of 0.02wt%Sr effectively increased the fluidity of the alloy, while an addition of Sc did not show any effect compared to when nothing was added. The maximum filling length was recorded for 0.01wt%TiB-0.02wt%Sr owing to the effect of the fine ${\alpha}$-Al grains. The macro-shrinkage ratio decreased, while the micro-shrinkage ratio increased with the addition of various eutectic modifiers. The highest ratio of micro-shrinkage was recorded for the 0.02wt%Sr condition. However, the total shrinkage ratio was nearly identical regardless of the amounts added in this study.

탄력성 있는 골수강 내고정물과 회전경첩형 슬관절 전치환물을 조합한 종양인공관절로 자가골의 골 용해를 감소시킬 수 있는가? (Do the Rotating Hinge-Flexible Intramedullary Nail Composites Alleviate Junctional Osteolysis in Megaprothesis Reconstruction for Bone Tumor?)

  • 송원석;조완형;조상현;전대근
    • 대한골관절종양학회지
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    • 제13권2호
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    • pp.96-104
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    • 2007
  • 목적: 슬관절 주위에서 탄력성 있는 골수강 내고정물과 회전경첩 슬관절 전치환물을 이용한 재건술이 종양인공관절과 자가골 경계부위의 골 흡수를 억제할 수 있는지를 35례에서 분석하였다. 대상 및 방법: 재건 술식은 다음과 같다. 1) 종양 절제, 2) 근위부나 원위부의 골수강에 다수의 Ender 정 삽입, 3) Ender 정과 Endo-Link 형 슬관절 전치환물을 강선 과 골 시멘트를 이용하여 결합 결과: 평균 추시기간은 53개월(30~79개월) 이었다. 최종 추시 상 29명의 환자가 가동관절을 유지하였다. 장관골 길이의 40% 이상을 절제한 군에서 종양인공관절과 자가골 경계부위 골질의 비후가 나타났다(p=0.028). 내고정 금속정의 파괴가 8례 있었으며, 조기 및 지연 감염으로 8례의 내고정물을 제거하였다. 본 재건술의 생존율은 6년에 33%였다. Musculoskeletal Tumor Society System 평가 법에 따른 기능적 결과는 26.8(89.3%)였다. 결론: 본 술식의 단-중기적 결과는 양호하였으며 합병증 발생시 재수술이 매우 용이하였다. 본 술식에서 관찰된 종양인공관절-자가골 이행 부위의 골 비후 소견은 추후 더 연구해 볼 문제로 생각된다.

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뇌졸중 환자를 위한 팀접근 재활프로그램의 효과 (The Effect of a Multidisciplinary Team Approach on the Rehabilitation of Stroke Survivors)

  • 조복희
    • 재활간호학회지
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    • 제6권2호
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    • pp.137-151
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    • 2003
  • The purpose of this study was to develop a multidisciplinary team approach program for stroke survivors, and to identify its effects on their rehabilitation. The team was composed of 7 members: a rehabilitation nurse, a physician, a physical therapist, an occupational therapist, a therapeutic recreational therapist, a nutritionist, and a researcher. A quasi-experimental study was performed with 36 subjects: 18 in the experimental group and 18 in the control group, using a noneqivalent control group pretest-posttest design. The experimental group participated 4 times in rehabilitation programsfocused on information and emotional support provided by the rehabilation team-and received telephone counseling from the researcher. The control group did not receive any treatment. The selection criteria for the subjects in this study were: (a) patients who were diagnosed as having had an ischemic stroke within the last year, (b) patients free of any communication disorder, (c) and those having a primary caregiver who could assist in filling out the form assessing the level of ADL. The data were collected from patients who had been discharged from a tertiary hospital, between October 1st, 1999 and September 30th, 2000. The data were analysed by $X^2$ test, Fisher's exact test, ANCOVA, Wilcoxon's rank sum test, and Wilcoxon's signed rank test using an SAS program. The results were as follows: 1. In terms of physical variables (blood pressure, grasp power, and ADL) 1) There was a significant difference in blood pressure between the two groups (systolic pressure P= .012, diastolic pressure P= .050). 2) There was also a significant difference in grasp power between the two groups (affected side : P= .012, unaffected side : P= .010). 3) There was no significant change in the level of ADL between the two groups. 2. In terms of psychosocial variables (depression, self-efficacy, self-esteem, and social activities) 1) There were no significant differences between the two groups. However, all four psychosocial variables showed a tendency to improve in the experimental group, while only two variables (depression and self-efficacy) showed a simalar tendency in the control group. 2) The level of social activities in the control group decreased significantly after a month (P= .050). 3. The level of life satisfaction improved in both groups, but no significant difference was found. Stroke has high recurrence rate and requires considerable follow-up care. The program used in this study was developed and designed for stimulting the rehabilitation process of stroke survivors. Through the program period of one month (meetings were held weekly), a positive effect was detected in physical variables, although the psychosocial variables did not improve significantly. In retrospect, a one month period may not be an adequate length of time to improve the psychosocial variables, as the stroke survivors were complicated cases, and most of them were elderly. Further research is therefore recommended by increasing the length of program, so that its effect can be more noticeable.

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스트레인 게이지법을 이용한 복합레진과 컴포머의 중합수축 평가에 관한 연구 (A STUDY ON THE EVALUATION OF POLYMERIZATION SHRINKAGE OF COMPOSITE AND COMPOMER USING STRAIN GAUGE METHOD)

  • 김윤철;김종수;권순원;김용기
    • 대한소아치과학회지
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    • 제29권1호
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    • pp.19-29
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    • 2002
  • 본 연구의 목적은 다양한 중합과정에 따른 복합레진과 컴포머의 수축 양상을 스트레인 게이지법(strain gauge method)을 이용하여 평가해보고자 하는 것이었다. 광중합기는 기존의 할로겐 시스템인 XL 3000(3M, USA)과 최근 소개된 plasma arc curing 시스템인 Flipo(LOKKI, France)를 사용하였고, 충전 재료는 복합레진인 Z-100(3M, USA)과 컴포머인 Dyract AP(Dentsply, Germany)를 사용하였다. 주형과 치아 와동 내에 충전된 실험재료의 중합수축을 각각 측정하였으며, 만능시험기를 이용하여 압축강도를 측정하였다. 중합수축 측정 결과 모두 중합초기에는 일시적인 재료의 팽창을 나타냈고, 그 후 약 1분간은 수축량이 급격히 증가하다가 증가의 폭이 점차 감소하는 양상을 보였다. 전반적으로 컴포머를 사용한 군에 비해 복합레진을 사용한 군에서 중합수축이 크게 나타났으며 plasma arc curing 시스템을 사용한 군에 비해 기존의 광조사 시스템 군에서 더 큰 중합수축을 보였다. 압축 강도의 측정결과는 컴포머 군에 비해 복합레진 군에서 크게 나타났다. 이상의 결과를 종합해 볼 때, plasma arc curing unit와 컴포머의 사용은 시술시간의 단축과 항우식 효과를 감안한다면 소아치과 영역에서의 사용이 긍정적으로 고려될 수 있다고 생각된다.

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저장유통 조건에 따른 1,000 mL 카톤팩의 벌지현상 (Bulge Characteristics of 1,000 mL Carton Pak according to the Different Storage Conditions)

  • 박종대;정관섭
    • 한국식품저장유통학회지
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    • 제10권3호
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    • pp.293-296
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    • 2003
  • 저장온도에 따른 1,000 mL 카톤팩의 벌지를 측정하기 위하여 원지 board의 물성을 측정하고, 저장조건에 따라 벌지를 측정하였다. 카톤팩 원지의 함수율은 5.6~7.0%, stiffness는 MD(machine direction) 방향이 243.3~266.7 g/cm, CD(cross direction) 방향이 99.2~109.2 g/cm였다. 카톤팩 낱장의 중량은 29.17~31.26 g이었다. 6$^{\circ}C$에 저장하면서 벌지를 측정한 결과, 저장 7일 후 6.33~6.93 mm였다. 1$0^{\circ}C$에 저장하면서 벌지를 측정한 결과, 저장 7일 후 7.26~8.56 mm였다. 1$0^{\circ}C$에 저장하면서 매일 1시간씩 상온 shock 처리 후 벌지를 측정한 결과, 저장 7일 후 8.66 mm였다. 저장온도 조건에 따른 카톤팩의 벌지는 6$^{\circ}C$ < 1$0^{\circ}C$ < 1$0^{\circ}C$+상온 shock순으로 증가하였다. 따라서 벌지 예방의 최선책은 원지 및 카톤팩의 보관 및 관리 철저, 그리고 충전 후 냉장유통 과정에서 온도변화를 적게 해주는 것이라고 사료되며 본 실험결과가 카톤팩 벌지에 대한 최초의 연구보고라 생각된다.

단계성토에 따른 연약지반의 전단강도 및 압밀거동 특성 (Characteristics of Shear Strength and Consolidation Behavior of Soft Ground according to Stage Fill)

  • 방성택
    • 한국지반환경공학회 논문집
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    • 제21권7호
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    • pp.17-26
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    • 2020
  • 해성점토로 구성된 서남해안 지역의 연약지반은 퇴적물의 성분, 입자크기의 분포, 입자형상, 흡착이온 및 간극수의 특성, 조류, 온도 등에 의해 많은 영향을 받는다. 또한, 응력이력, 간극수의 변화, 용탈과정, 가스형성 등의 지반공학적 특성은 매우 복잡한 양상을 나타내고 있다. 본 연구에서는 서남해안 연약지반을 대상으로 압밀에 따른 강도증가 특성을 규명하기 위하여 현장시험 및 실내시험을 통하여 연약지반의 물리적·역학적 특성을 평가하고 성토하중에 의한 지반의 침하, 간극수압, 수평변위 등 연약지반의 압밀거동을 파악하기 위하여 간극수압계, 침하계, 경사계, 층별침하계 등의 계측기를 설치하고, 지반의 전단강도증가를 확인하기 위해 단계별로 피에조콘 관입시험을 실시하였다. 이와 같은 실험을 통하여 단계별 성토에 따른 지반의 전단강도증가를 확인하고 압밀침하량을 측정하여 기존에 제시된 경험적 방법 및 이론에 의한 강도증가와 압밀측정치를 비교하여 강도증가율 및 압밀거동을 분석하였다.

국내외 치과 의료수가 비교현황 : 한국, 일본, 독일, 미국을 중심으로 (Comparative study on Dental fees of Korea, Japan, Germany and United States)

  • 류재인;김철신;정세환;신보미
    • 대한치과의사협회지
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    • 제53권4호
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    • pp.266-274
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    • 2015
  • The price for health service are decided by very complicated process because many of factors are related with them. The RBRVS(resource-based relative value scale) were used to calculate the Korean health service fees including dental fees. This study aimed to compare dental fees of Korea with other countries, such as Japan, Germany, and the US for evaluating the adequacy. Dental fees were categorized as oral evaluation and imaging, dental treatment including restorative, periodontal, and surgical work, and preventive treatment and compared by each country. The official documents about dental fees were collected from Korea, Japan, Germany, and the US. Each fee was presented as their own currency at first. Then they were converted into Korean won (KRW) by applying the market exchange rates at a specific point of time. Finally the fees were adjusted by purchasing power parities (PPPs) which equalize the different currencies. In general, the level of Korean fees were markedly low compared to those of Japan, Germany, and the US. German fees were similar or higher than that of Japan, and the US. The Korean fees were lower than three other countries 1.2~4.1 times for oral evaluation and 2.2~7.3 times lower for panoramic radiography. The endodontic fees of Japan, Germany, and the US were higher 1.8~15.3 times and 4.0~35.9 times for the deciduous teeth extraction compared to the Korean. In Japan the prophylaxis was 3.2 times more priced than the Korean fee. Exceptionally, the fees for re-evaluation, amalgam filling, and scaling were lower priced in Japan than other countries. This study has limitations on the items in definition and contents of dental practices units which were not exactly comparable and differently determined by countries. However, this study is meaningful because it surveyed the price levels to compare four different countries and then applied PPPs adjustment. This finding can be used to develop the dental RBRVs of Korean national health insurance and will contribute to improving the payment systems of health care.