• 제목/요약/키워드: soft breakdown

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Nanotribology를 이용한 PMMA 박막의 Hardness와 Elastic Modulus 특성 연구 (Characteristics of Hardness and Elastic Modulus of PMMA Film using Nano-Tribology)

  • 김수인;김현우;노성철;윤덕진;장홍준;이종림;이창우
    • 한국진공학회지
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    • 제18권5호
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    • pp.372-376
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    • 2009
  • 현대 반도체 공정에서 일정한 패턴을 생성하기 위하여 리소그래피(Lithography) 공정을 이용하고 있으나 선폭의 감소로 인하여 기존 UV를 이용한 PR(Photoresist) 이외에 e-beam을 이용한 PMMA(Polymethyl methacrylate) 리소그래피에 대한 관심이 높아지고 있다. 또한 리소그래피에 의하여 생성된 패턴은 이후 세정 공정에서 잔류물을 제거하는 과정에서 패턴 붕괴를 일으키게 되는데 이러한 패턴 붕괴에 대한 방어력은 패턴 형성 물질의 탄성력(Elastic modulus)과 비례하는 것으로 알려져 있다. 이 논문에서 우리는 PMMA의 soft-baking 이후 Hardness(H)와 Elastic modulus(Er)의 변화를 압입력을 25 uN에서 8,500 uN으로 134.52 uN 간격으로 증가시키며 측정하였다. 또한 이 실험에서 Hardness(H)와 Elastic modulus(Er)는 Hysitron사의 Triboindenter를 이용하여 측정하였고 압입팁은 Berkovich 팁을 사용하였다.

단순공정으로 제작된 마이크로/나노 하이브리드 채널의 불균형 동전기성을 이용한 미세혼합기 연구 (Simple Fabrication of Micromixer Based on Non-Equilibrium Electrokinetics in Micro/Nano Hybrid Fluidic System)

  • 유사무엘;김선민
    • 대한기계학회논문집B
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    • 제35권4호
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    • pp.385-390
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    • 2011
  • 본 연구에서는 미세채널과 나노채널의 교차부에 불균형 동전기성을 이용한 미세혼합기를 개발하였다. 채널 내 용액의 혼합은 인가된 전압에 의한 전기삼투유동과 미세채널과 나노채널 교차 부에서의 불균형 동전기성에 의한 와류현상에 의해 이루어진다. 미세채널은 PDMS 을 이용하여 소프트리소그래피 공정으로 제작하였고, 나노채널은 미세채널의 특정위치에 전기적 충격에 의한 PDMS 의 파괴로 매우 간단하게 제작하였다. 혼합성능을 평가하기 위하여 형광물질인 Rhodamine B 용액을 이용하여 혼합 전과 후의 형광 분포를 분석하였으며, 약 90%의 혼합을 얻을 수 있었다. 본 연구의 미세혼합기는 복잡한 공정을 요구하지 않고 매우 간단하게 제작되었으며, 생화학시료 분석을 위한 미세시스템에 활용될 수 있다.

Through Knee Amputation: Technique Modifications and Surgical Outcomes

  • Albino, Frank P.;Seidel, Rachel;Brown, Benjamin J.;Crone, Charles G.;Attinger, Christopher E.
    • Archives of Plastic Surgery
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    • 제41권5호
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    • pp.562-570
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    • 2014
  • Background Knee disarticulations (KD) are most commonly employed following trauma or tumor resection but represent less than 2% of all lower extremity amputations performed in the United States annually. KDs provide enhanced proprioception, a long lever arm, preservation of adductor muscle insertion, decreased metabolic cost of ambulation, and an end weight-bearing stump. The role for KDs in the setting of arterial insufficiency or overwhelming infection is less clear. The purpose of this study is to describe technique modifications and report surgical outcomes following KDs at a high-volume Limb Salvage Center. Methods A retrospective study of medical records for all patients who underwent a through-knee amputation performed by the senior author (C.E.A.) between 2004 and 2012 was completed. Medical records were reviewed to collect demographic, operative, and postoperative information for each of the patients identified. Results Between 2004 and 2012, 46 through-knee amputations for 41 patients were performed. The mean patient age was 68 and indications for surgery included infection (56%), arterial thrombosis (35%), and trauma (9%). Postoperative complications included superficial cellulitis (13%), soft tissue infection (4%), and flap ischemia (4%) necessitating one case of surgical debridement (4%) and four transfemoral amputations (9%). 9 (22%) patients went on to ambulate. Postoperative ambulation was greatest in the traumatic cohort and for patients less than 50 years of age, P<0.05. Alternatively, diabetes mellitus and infection reduced the likelihood of postoperative ambulation, P<0.01. Conclusions Knee disarticulations are a safe and effective alternative to other lower extremity amputations when clinically feasible. For patient unlikely to ambulate, a through-knee amputation maximizes ease of transfers, promotes mobility by providing a counterbalance, and eliminates the potential for knee flexion contracture with subsequent skin breakdown.

Effects of Electrostatic Discharge Stress on Current-Voltage and Reverse Recovery Time of Fast Power Diode

  • Bouangeune, Daoheung;Choi, Sang-Sik;Cho, Deok-Ho;Shim, Kyu-Hwan;Chang, Sung-Yong;Leem, See-Jong;Choi, Chel-Jong
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제14권4호
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    • pp.495-502
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    • 2014
  • Fast recovery diodes (FRDs) were developed using the $p^{{+}{+}}/n^-/n^{{+}{+}}$ epitaxial layers grown by low temperature epitaxy technology. We investigated the effect of electrostatic discharge (ESD) stresses on their electrical and switching properties using current-voltage (I-V) and reverse recovery time analyses. The FRDs presented a high breakdown voltage, >450 V, and a low reverse leakage current, < $10^{-9}$ A. From the temperature dependence of thermal activation energy, the reverse leakage current was dominated by thermal generation-recombination and diffusion, respectively, at low and high temperature regions. By virtue of the abrupt junction and the Pt drive-in for the controlling of carrier lifetime, the soft reverse recovery behavior could be obtained along with a well-controlled reverse recovery time of 21.12 ns. The FRDs exhibited excellent ESD robustness with negligible degradations in the I-V and the reverse recovery characteristics up to ${\pm}5.5$ kV of HBM and ${\pm}3.5$ kV of IEC61000-4-2 shocks. Likewise, transmission line pulse (TLP) analysis reveals that the FRDs can handle the maximum peak pulse current, $I_{pp,max}$, up to 30 A in the forward mode and down to - 24 A in the reverse mode. The robust ESD property can improve the long term reliability of various power applications such as automobile and switching mode power supply.

국산밀 품종의 밀가루 특성과 가공적성 I. 밀가루 특성 (Flour Characteristics and End-Use Quality of Korean Wheat Cultivars I. Flour Characteristics)

  • 강천식;박철수;박종철;김학신;정영근;김경호;김기종;박기훈;김정곤
    • 한국육종학회지
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    • 제42권1호
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    • pp.61-74
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    • 2010
  • 국내에서 육성된 주요 26개 품종의 품질평가를 통하여 국내산 밀의 품질향상과 향후 소비자 요구에 맞는 용도별 고품질 밀 품종육성을 위한 기초자료로 이용하고자 용도별 수입원맥 6종과 시중에서 유통되고 있는 밀가루 5종을 비교 평가하였다. 밀가루의 물리적 특성에서 다홍밀, 그루밀, 밀성밀, 올그루밀, 서둔밀, 탑동밀과 우리밀은 연질 수입 원맥의 밀가루 입자 크기와 비슷하였으며, 적중밀, 조은밀, 수강밀과 연백밀은 제빵용에 주로 사용되는 춘파용 경질밀과 비슷하였다. 회분함량과 손상전분 함량은 수입밀과 시중 밀가루와 비슷하였으나 밀가루 밝기는 어두웠다. 밀가루 입자 크기는 회분, 손상 전분 함량과 밀가루 밝기와 밀접한 관계가 있었기 때문에 밀가루의 밝기는 회분함량이 많고, 입자크기가 크고, 손상전분이 많을수록 어두웠다. 단백질 특성에서 연질 수입원맥이나 시중에 판매되는 제과용 수입 밀가루의 단백질함량과 비슷한 수준을 보인 품종은 백중밀, 진품밀, 밀성밀, 올그루밀, 새올밀과 우리밀이었으며, 수입경질 원맥이나 수입산 빵용 밀가루와 비슷한 품종은 한백밀, 조은밀, 조품밀, 금강밀과 수강밀이었지만 이들 품종의 단백질의 질적 특성을 나타내는 침전가는 낮게 나타났다. 국산밀 품종의 믹소그래프 특성에서 가수량과 반죽시간은 수입밀과 시중 밀가루와 비교하여 비교적 높게 나타났다. 단백질함량이 증가할수록 침전가와 반죽 가수량이 증가하였으며, 침전가는 반죽 가수량, 반죽시간, 빵 반죽 발효높이와 고도의 정의 상관을 보였다. 전분특성에서는 호주에서 수입되는 호주산 표준 백립계밀(ASW)가 다른 종류의 밀가루보다 아밀로스 함량이 낮고, 최고점도, breakdown과 setback은 제일 높게 나타났다. 국산밀 품종은 아밀로스함량이 높아 국수용 수입 원맥이나 시중 수입산 밀가루보다 최고점도가 낮은 것으로 나타났다.

The Application of NIRS for Soil Analysis on Organic Matter Fractions, Ash and Mechanical Texture

  • Hsu, Hua;Tsai, Chii-Guary;Recinos-Diaz, Guillermo;Brown, John
    • 한국근적외분광분석학회:학술대회논문집
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    • 한국근적외분광분석학회 2001년도 NIR-2001
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    • pp.1263-1263
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    • 2001
  • The amounts of organic matter present in soil and the rate of soil organic matter (SOM) turnover are influenced by agricultural management practice, such as rotation, tillage, forage plow down direct seeding and manure application. The amount of nutrients released from SOM is highly dependent upon the state of the organic matter. If it contains a large proportion of light fractions (low-density) more nutrients will be available to the glowing crops. However, if it contains mostly heavy fractions (high-density) that are difficult to breakdown, then lesser amounts of nutrients will be available. The state of the SOM and subsequent release of nutrients into the soil can be predicted by NIRS as long as a robust regression equation is developed. The NIRS method is known for its rapidity, convenience, simplicity, accuracy and ability to analyze many constituents at the same time. Our hypothesis is that the NIRS technique allows researchers to investigate fully and in more detail each field for the status of SOM, available moisture and other soil properties in Alberta soils for precision farming in the near future. One hundred thirty one (131) Alberta soils with various levels (low 2-6%, medium 6-10%, and high >10%) of organic matter content and most of dry land soils, including some irrigated soils from Southern Alberta, under various management practices were collected throughout Northern, Central and Southern Alberta. Two depths (0- 15 cm and 15-30 cm) of soils from Northern Alberta were also collected. These air-dried soil samples were ground through 2 mm sieve and scanned using Foss NIR System 6500 with transport module and natural product cell. With particle size above 150 microns only, the “Ludox” method (Meijboom, Hassink and van Noorwijk, Soil Biol. Biochem.27: 1109-1111, 1995) which uses stable silica, was used to fractionate SOM into light, medium and heavy fractions with densities of <1.13, 1.13-1.37 and >1.37 respectively, The SOM fraction with the particle size below 150 microns was discarded because practically, this fraction with very fine particles can't be further separated by wet sieving based on density. Total organic matter content, mechanical texture, ash after 375$^{\circ}C$, and dry matter (DM) were also determined by “standard” soil analysis methods. The NIRS regression equations were developed using Infra-Soft-International (ISI) software, version 3.11.

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임산부의 산전관리와 산욕기 영양실태에 관한 연구 (Clinical Study on Prenatal care, and Dietary Intakes for Pregnant Women and new Mothers)

  • 차순향;박재순
    • Journal of Nutrition and Health
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    • 제9권4호
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    • pp.36-46
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    • 1976
  • This study was projected to provide basic data on prenatal care for future direction in maternity and child care, and also to investigate the diet of women during pregnancy and the period directly afterwards in order to offer to mothers appropriate advice for the improvement of nutritional standards. A clinical study on prenatal care was based on 1054 delivery cases. A nutritional survey was performed on 174 mothers admitted to the department of obstetrics at St. Mary's Hospital during the period of March, 1975 to February, 1976. The results obtained are summarized as follows; I. Clinical study on prenatal care 1) The age distribution showed 59.4% of the mothers were between the ages of 25 to 29 years old. 2) The gestational period was highest between the 37th and 40th gestational weeks. 33.7% of the mothers were primigravidae and 31.8% of them primiparae. 3) 41.3% of the mothers had not received prenatal care or had only received it once before. 4) Induced deliveries were 61.8% and spontantaneous deliveries 38.2%. 61.9% of the mothers had received prenatal care, while those without prenatal care accounted for 61.6% of the total induced deliveries. 5) Low birth weights were 7.7% and 5.0% of the mothers had received prenatal care, while 11.5% had no prenatal care. 6) There were 1.13% of still births, 0.32% of the mothers had prenatal care and the remainder did not have prenatal care. 7) Of those receiving prenatal care, 2.1% showed in the $0{\sim}3$ Apgar score group, 6.3% in the $4{\sim}6$ Apgar score group, and 91.6% in the $7{\sim}10$ Apgar score group. Among the non-prenatally cared for group 5.0% of the newborns were in the $0{\sim}3$ Apgar score group, 9.7% were in $4{\sim}6$ Apgar score group and 85.3% were in the $7{\sim}10$ Apgar score group. 8) Obstetrical complications were developed in 11.86% of the pregnant women when they were hospitalized. Among the group receiving the prenatal care 8.1% of the mothers had obstetrical complications. In the group without prenatal care 17.16% of the mothers had obstetrical complications. The most common obstetrical complication was malpresentation. 9) The first prenatal care was received between the 37th and 40th gestationl weeks. II. Food intake during pregnancy The following are the results from the questionnaires of the mothers concerning diets during pregnancy; 1) Main meals and snacks In 32.2% of the cases, their main meals during the diet amounted to more than was usually eaten at other times. In 67.8% of the cases, their main meals during the diet were the same as that usually eaten. In 22.4% of the cases, snacks during the diet amounted to more than usually eaten at other times. In 77.6% of the cases, snacks during the diet were the same as usually eaten. 2) Itemized list The mothers made a special effort to include certain items in their diets, the following is a breakdown of those items; a. egg, meat, fish 33.3% b. fruit, vegetables 32.2%. c. milk, fruit juice 18.4% d. cake, bread 2.9% e. nothing special 13.2% 3) Milk 44.8% of the mothers had at least one cup of milk everyday. 33.4% of the mothers had at least one cup of milk on occasion. 15.5% of the mothers did not have any milk. 4) Vitamins 39.7% of the mothers had vitamins everyday. 24.7% of the mothers had vitamins occasionally. 35.6% of the mothers did not have any vitamins. 5) Anemic symptoms 9.2% of the mothers very often had anemic symptoms during pregnancy. 39.1% of the mothers often had anemic symptoms during pregnancy. 51.7% of the mothers did not have anemic symptoms at all. 6) Taboos on food 23% of the mothers recognized 'taboos' on food during pregnancy 27% of the mothers displayed on uncertainty about the 'taboos' on food during pregnancy 50% of the mothers displayed indifference toward the taboos. III. Nutritional survey on the new mothers diet. 1) The diets for new mothers can be divided into four categories, such as general diet, low sodium diet, soft diet and liquid diet. 2) Cooked rice and seaweed soup were the main foods for the new mothers as has been the traditional diet for Korean mothers. 3) The average diet contained 1,783g. And the average consumption of the basic food groups per capita per day was 1,265g for cereals and grains, 456g for meats and legumes, 58g for fruits and vegetables, 0g for milk and fish and 4g for fats and oils. 4) In addition to the 1,783g of food in the main diet there was also 142.8g of food taken as snacks. 5) The average daily consumption of calories and nutrients was 2,697 Kcal and 123.4g for proteins, 44.9g for fats, 718.2mg for calcium, 14mg for iron, 2,101.4 I.U. for vitamin A, 0.43mg for thiamine, 1.02mg for riboflavin, 15.88mg for niacin, 5.26mg for ascorbic acid. When these figures are compared with the recommended allowances for new mothers in Korea, the calories and nutrients taken in were satisfactory. But the intake of minerals and vitamins was below the recommended allowance.

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시판 고구마전분의 이화학적 특성 (Physicochemical Properties of Commercial Sweet Potato Starches)

  • 백만희;차동수;박현진;임승택
    • 한국식품과학회지
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    • 제32권4호
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    • pp.755-762
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    • 2000
  • 고구마, 감자, 옥수수전분의 회분과 조단백질 함량은 각각 $0.36{\sim}1.02%$$0.04{\sim}0.14%$였으며, 고구마전분의 백도는 옥수수나 감자전분보다는 낮은 값을 보였다. 평균입자크기는 $14.23{\sim}21.08\;{\mu}m$로 작은 입자와 큰 입자 그룹으로 분리된 분포를 보였다. 고구마전분의 호화개시온도는 $74.0{\sim}80.35^{\circ}C$를 보였는데, D사 전분이 가장 낮은 값을, 필리핀산(P사) 전분이 가장 높은 값을 보였다. 고구마전분 페이스트의 최고점도는 제조사에 따라 차이가 컸으며, HL사가 가장 높은 값을, S사가 가장 낮은 값을 보였고, 옥수수전분보다는 높고, 감자전분보다는 낮은 값을 보였다. 전분현탁액을 호화시킨 후 빛투과도를 측정한 결과 HK사가 20.67%로 가장 높은 값을 보였고, 다른 전분은 $11.14{\sim}14.76%$를 보였다. 고구마전분겔(10%)의 조직감 특성은 필리핀산(P사)과 S사를 제외한 고구마전분은 부드럽고 약한 겔을 형성하였으며, 제조사에 따라 다르게 나타났다. 저장 1일에는 P사 전분이 견고성, 뭉치는 성질, 씹히는 성질이 가장 높은 값을 보인 반면, 저장 3일에는 S사가 가장 높은 값을 보였다. 탄력성은 저장에 따라 증가하는 경향이었으며, 접착성은 저장 3일에 P사와 S사에서만 높게 나타났으며, 감자전분의 조직감과 비슷하였다. 고구마전분겔(10%)의 냉 해동안정성은 옥수수전분 보다는 높고 감자전분 보다는 낮게 나타났으며, S사가 3회 반복시 17.53%를 보인 반면, P사 고구마전분이 65.72%로 3.7배의 높은 값을 보였다. 이상의 결과에서 보듯이 제조사가 각기 다른 고구마전분의 물리적 특성은 다소 차이가 있었으며 특히 필리핀산 전분이 한국산 전분과 큰 차이를 나타냈다.혀졌다. 또한 instant curry 제품을 사용하여 pH 1.2 조건하에서 nitrite 분해능을 측정한 결과 제품별 차이는 있었으나 12${\sim}$28% 정도의 분해능을 가지고 있었다.수 변환중 cross-over가 일어나고 이후의 진동수 영역에서는 저장탄성율이 손실탄성율보다 높은 값을 나타내었으며, 24시간 경과 후 겔을 형성하여 겔화제로서의 이용 가능성을 보여주었다. 항산화 효과는 뚜렷한 상관관계가 발견되지 않았다.CaSO_4$, GDL, $MgCl_2$, $Ca-gluconate+MgCl_2$, $GDL+CaSO_4$ 첨가구는 0.3%에서, 그리고 $Ca-gluconate+CaSO_4$ 첨가구는 0.4%에서 높게 나타났으며 그 중 0.3% $GDL+CaSO_4$ 첨가구가 적당한 경도를 가지면서도 부드럽고 고소한 맛이 강하여 가장 높은 기호도를 나타내었다.cids은 $190^{\circ}C$까지는 $2.51{\sim}4.41$ ppm으로 거의 변화를 보이지 않다가 $210^{\circ}C$에서 18.92 ppm으로 급증하였고, 이후 $220^{\circ}C$에서 7.20ppm, $230^{\circ}C$에서 5.56 ppm으로 점진적으로 감소하였다. 이는 nonanoic acid, palmitic acid, stearic acid등이 고온가열에 의해 생성되었다가 이들이 열분해로 소실되었기 때문으로 생각된다.평균치는 34점이었으며 여윔에서는 너무 살찜으로 갈수록 사회적 체형불안도가 상승하는 경향을 나타내었다. 후쿠오카 지역의 체형 불안 도가 대구지역보다 유의적으로 높았다. 한 일 여대생의 자기 체형인식 및 체형 불안도에 관한 비교연구에서

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