• 제목/요약/키워드: Free-surface

검색결과 3,939건 처리시간 0.034초

Analysis on the Langmuir Adsorption Isotherm of the Over-Potentially Deposited Hydrogen (OPD H) at the Polycrystalline Au|Acidic Aqueous Electrolyte Interface Using the Phase-Shift Method

  • Chun Jang H.;Jeon Sang K.
    • 전기화학회지
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    • 제4권3호
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    • pp.118-124
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    • 2001
  • 순환전압전류 및 교류임피던스 기법을 이용하여 다결정 $0.5M\;H_2SO_4$수용액 계면에서 음극 $H_2$발생 반응을 위한 과전위 전착(흡착)된 수소의 Langmuir흡착등온식을 연구조사 하였다. 다결정 $Au|0.5M\;H_2SO_4$수용액 계면에서, 최적중간주파수일 때 위상이동 $(0^{\circ}\leq{-\phi}\leq90^{\circ})$ 거동은 표면피복율$(1\geq{\theta}\geq0)$ 거동에 정확하게 상응한다. 최적중간주 파수일 때 위상이동 변화 $({-\phi}\;vs.\;E)$즉 위상이동 방법은 다결정 $Au|0.5M\;H_2SO_4$수용액 계면에서 음극 $H_2$발생 반응을 위한 과전위 전착(흡착)된 수소의 Langmuir 흡착등온식$(\theta\;vs.\;E)$을 추정할 수 있는 새로운 방법으로 사용될 수 있다. 다결정 $Au|0.5M\;H_2SO_4$ 수용액 계면에서, 과전위 전착(흡착)된 수소의 흡착평형상수(K)와 표준자유에너지 $({\Delta}G_{ads})$는 각각 $2.3\times10^{-6}$$32.2kJ\;mol^{-1}$이다.

한국인에 대한 새로운 관절주위 잠김금속판의 해부학적 적합성: 사체를 이용한 연구 (Anatomic Conformity of New Periarticular Locking Plates for Koreans: A Biomechanical Cadaveric Study)

  • 윤용철;오종건;김영우;김학준;문홍주;김남렬
    • Journal of Trauma and Injury
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    • 제26권3호
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    • pp.163-169
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    • 2013
  • Purpose: This study was conducted to confirm the anatomic conformity of the new periarticular locking plates designed by Zimmer on Korean adult bones and to identify the structures at risk during the application of these implants. Methods: The study was performed on the humerus, radius, and tibia of 10 adult cadavers(6 males and 4 females) procured from the cadaveric lab of our hospital. Anteroposterior (AP) and lateral X-rays were taken to confirm that the cadavers were free of any unusual lesions or anatomic variations. We used the 3.5-mm proximal humerus plate, 2.7-mm distal radius plate, 3.5- and 5.0-mm proximal tibia plates, and 3.5-mm distal tibia plate developed by Zimmer, Inc. (Zimmer periarticular locking plate). The longest plate from each group was used to confirm anatomical conformity. Standard approaches were used for each area, and soft tissue was retracted in order to pass the plate beneath the muscle. The position of the plate was confirmed using standard AP and lateral view X-rays. After this procedure had been completed, the region was dissected along the length of the implant to determine the conformity of the implant to bone and the penetrations of screws into the articular surface or violations of any vital structures, such as nerves, blood vessels, or tendons. Results: Excellent anatomical conformity was observed with Zimmer periarticular locking plates for Korean adults. The tibial nerve and the posterior tibial artery were found to be structures at risk when applying a distal tibial plate. Conclusion: Additional posterolateral fixation is recommended when dealing with cases of tibial plateau fracture when the fracture line extends to the posterolateral cortex. We recommend taking proper views using 10~15 degrees of internal rotation to ensure correct screw length and, thus, avoid penetration of vital structures and tendons.

실험적으로 전십자 인대를 단열한 개에서 TPLO의 핵의학적 평가 (Scintigraphic Evaluation of Dogs with Experimentally Transected Cranial Cruciate Ligaments Treated Using Tibial Plateau Leveling Osteotomy)

  • 이재영;김중현;이원국;강성수;배춘식;최석화
    • 한국임상수의학회지
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    • 제22권1호
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    • pp.21-25
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    • 2005
  • This study was performed to assess therapeutic effect of the tibial plateau leveling osteotomy (TPLO) in dogs with experimentally transected cranial cruciate ligaments (CrCL). Nine healthy adult Beagle dogs were transected left CrCL under general anesthesia. The dogs were assigned to TPLO and non-TPLO control groups. The TPLO procedures for correcting the CrCL rupture in the left stifle of dogs were performed under sterile conditions. Before TPLO procedures, all dogs were screened by orthopedic and radiographic examinations. Dogs were lameness free for the previous three months, and when examined at the walk and trot on a hard surface, in a straight line and on a circle. Lateral and craniocaudal radiographs were done to confirm the soundness of the both knee joint in dogs and not detectable lesions were diagnosed. The dogs were intravenously injected with a 10 mci/kg of 99mTechnetium-methylene diphosphonate (99mTc-MDP) under general anesthesia. Scintigraphs were obtained using a large field of view gamma camera equipped a parallel-hole, low-energy about 3 hours after intravenous injection of 99mTc-MDP. Before CrCL transection and 4, 8, and 12 weeks after the procedures, scintigraphy were conducted. Bone uptake of the left stifle joint increased after the procedures in all dogs. When the bone uptake from the TPLO procedure was compared with that of the control, there was a significant difference (p < 0.05). At 12 weeks after the TPLO procedure, the dogs showed normal anatomical posture and gait. It is concluded that TPLO procedure was effective in reconstruct of the stifle joint in dogs with CrCL rupture.

Phloroglucinol Inhibits the in vitro Differentiation Potential of CD34 Positive Cells into Endothelial Progenitor Cells

  • Kwon, Yi-Hong;Lee, Jun-Hee;Jung, Seok-Yun;Kim, Jae-Won;Lee, Sang-Hun;Lee, Dong-Hyung;Lee, Kyu-Sup;Lee, Boo-Yong;Kwon, Sang-Mo
    • Biomolecules & Therapeutics
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    • 제20권2호
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    • pp.158-164
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    • 2012
  • Inhibiting the bioactivities of circulating endothelial progenitor cells (EPCs) results in significant inhibition of neovessel formation during tumor angiogenesis. To investigate the potential effect of phloroglucinol as an EPC inhibitor, we performed several in vitro functional assays using $CD34^+$ cells isolated from human umbilical cord blood (HUCB). Although a high treatment dose of phloroglucinol did not show any cell toxicity, it specifically induced the cell death of EPCs under serum free conditions through apoptosis. In the EPC colony-forming assay (EPC-CFA), we observed a significant decreased in the small EPC-CFUs for the phloroglucinol group, implying that phloroglucinol inhibited the early stage of EPC commitment. In addition, in the in vitro expansion assay using $CD34^+$ cells, treatment with phloroglucinol was shown to inhibit endothelial lineage commitment, as demonstrated by the decrease in endothelial surface markers of EPCs including $CD34^+$, $CD34^+/CD133^+$, $CD34^+/CD31^+$ and $CD34^+/CXCR4^+$. This is the first report to demonstrate that phloroglucinol can inhibit the functional bioactivities of EPCs, indicating that phloroglucinol may be used as an EPC inhibitor in the development of biosafe anti-tumor drugs that target tumor angiogenesis.

Print Mottle : Causes and Solutions from Paper Coating Industry Perspective

  • Lee, Hak-Lae
    • 펄프종이기술
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    • 제40권5호
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    • pp.60-69
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    • 2008
  • The principal reasons for applying a pigment coating to paper are to improve appearance and printability. The pigment coating provides a surface that is more uniform and more receptive to printing ink than are the uncoated fibers and, in turn, both facilitates the printing process and enhances the graphic reproduction. The improvement in print quality is readily apparent, especially in image areas or when multiple colors are involved. Although pigment coating of paper is to improve the printability, coated paper is not completely free from printing defects. Actually there are a number printing defects that are observed only with the coated papers. Among the printing defects that are commonly observed for coated papers, print mottle during multi-color offset printing is one of the most concerned defects, and it appears not only on solid tone area but also half dot print area. There are four main causes of print mottle ranging from printing inks, dampening solution, paper, and printing press or its operation. These indicates that almost every factors associated with lithographic printing can cause print mottle. Among these variation of paper quality influences most significantly on print mottle problems in multicolor offset printing, and this indicates that paper is most often to be blamed for its product deficiency as far as print mottle problems are concerned. Furthermore, most of the print mottle problems associated with paper is observed when coated papers are printed. Uncoated papers rarely show mottling problems. This indicates that print mottle is the most serious quality problems of coated paper products. Overcoming the print mottle is becoming more difficult because the operating speeds of coating and printing machines are increasing, coating weights are decreasing, and the demands on high-quality printing are increasing. Print mottle in offset printing is caused by (a) nonuniform back trap of ink caused by a nonuniform rate of ink drying, referred as "back trap mottle, and (b) nonuniform absorption of the dampening solution. Furthermore, both forms of print mottle have some relationship to the structure of the coated layer. The surest way of eliminating ink mottling is to eliminate unevenness in the base paper. Coating solutions, often easier to put into practice, should, however, be considered. In this paper the principal factors influencing print mottle of coated papers will be discussed. Especially the importance of base paper roughness, binder migration, even consolidation of coating layers, control of the drying rate, types of binders, etc. will be described.

PIV를 이용한 흡수조 내 유속분포 및 와류강도 측정에 대한 연구 (A Study of the Velocity Distribution and Vorticity Measurement in the Pump Sump Using PIV)

  • 변현혁;김서준;윤병만
    • 대한토목학회논문집
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    • 제40권2호
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    • pp.145-156
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    • 2020
  • 최근 도시지역의 불투수율 증가로 인해 내수침수 위험성이 증가하고 있다. 이에 도시침수 방지대책으로 빗물펌프장의 증설 및 신설에 대한 필요성이 부각되고 있다. 빗물펌프장의 효율을 증가시키기 위해서는 흡수조에서 발생하는 와류의 제어가 필요하다. 따라서 와류를 효과적으로 제어하기 위해서 펌프 흡수조 내 흐름특성 분석이 필요하다. 이에 본 연구에서는 입자영상유속측정법을 이용하여 흡수조 내 유속분포 및 와류강도를 측정하기 위한 촬영 및 분석 조건들에 대한 민감도 분석을 실시하여 흡수조 내 유속 및 와류강도 측정의 한계를 확인하고 최적 방법들을 제시하고자 한다. 이를 위해 우선 레이저를 이용하여 흡수조 내 흐름을 촬영하였고, 상관영역 크기와 촬영 시간간격 및 측점 간격의 변화에 따른 유속분포와 와도분포를 비교하여 민감도를 검토하였다. 본 연구에서 대상으로 한 흐름조건의 자유수면와류의 경우 상관영역 크기가 와류 크기의 약 13 % 이상에서는 유속 산정 정확도가 감소하는 것으로 나타났으며, 연속되는 두 장의 영상 간 입자의 변위가 1 mm 이상이 되면 연직방향의 흐름 때문에 이탈되는 입자들이 많아져 정확도가 감소하는 것으로 나타났다. 또한 자유수면와류가 차지하는 격자의 개수가 증가할수록 와도의 크기가 커지는 것으로 나타났다. 이와 같은 연구결과는 입자영상유속계를 활용한 흡수조 내 유속분포 및 와류강도 측정 시 촬영 및 영상분석 조건을 결정하는데 기초자료로 활용될 것으로 기대된다.

제주지역에서 예취높이에 따른 양마의 생육특성, 사료수량 및 조성분 변화 (Effects of Cutting Height on Agronomic Characteristics, Forage Yield, and Chemical Composition of Kenaf in Jeju)

  • 조남기;강영길;송창길;조영일;오은경;고미라;박정식
    • 한국초지조사료학회지
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    • 제22권1호
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    • pp.15-22
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    • 2002
  • 제주지역에서 예취높이에 따른 (2, 4, 6, 8 및 l0cm)에 따른 양마의 생육특성, 수량성 및 사료가치를 구명하기 위하여 2001년 4월 13일부터 10월 8일까지 시험한 결과는 다음과 같다. 초장은 2cm 예취에서 157.7cm였던 것이 예취높이가 높아짐에 따라 점차적으로 커져서 10cm 예취에서는 180.2cm로 커졌다. 엽수, 분지수, 경직경 및 주당 무게는 초장반응과 비슷한 경향이었다. 생초, 건물, 단백질 및 TDN 수량은 2cm 예취에서 각각 85.5MT/ha, 11.97MT/ha, 1.63MT/ha, 4.95MT/ha로 감수되었으나 예취높이가 높아짐에 따라 점차적으로 증가되어 10cm 예취에서 생초수량 113.7MT/ha, 건물수량 15.63MT/ha, 단백질수량 2.72MT/ha, TDN수량은 7.54MT/ha 증수되었다. 예취높이가 2cm에서 l0cm로 높아짐에 따라 조단백질 함량은 14.2%에서 17.6%로, 조지방 함량은 2.9%에서 3.9%로, NFE 함량은 24.2%에서 25.8%로, TDN 함량 35.5%에서 30.4%로, 조회분 함량은 9.9%에서 8.1%로 낮아졌다.

Brittle Culm 벼의 예취높이가 청예수량 및 영양가에 미치는 영향 (Effects of Cutting Height on Forage Yield and Nutritive Value of Brittle Culm-Rice)

  • 김영두;이재길;신현탁
    • 한국작물학회지
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    • 제42권5호
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    • pp.528-533
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    • 1997
  • Brittle culm벼의 예취높이를 구명하여 조사요로서의 수량 및 영양가를 평가하고자 섬진벼 및 Brittle culm인 KL501 품종을 공시하고 예취높이를 지상 0, 5, 10 및 20cm 달리하여 1996년 호남농업시험장 수도포장에서 수행한 결과를 요약하면 다음과 같다. 1. 재생초장, 경직경 및 재생경율은 예취높이를 높게 할수록 크고 높았으며 분얼경수는 품종 및 예취높이간유의성이 인정되었다. 2. 조단백질, 조지방 및 NFE 함량은 1차 예취시 예취높이가 높아짐에 따라 증가하나 조섬유 및 조회분함량은 이와 반대의 경향이며 2차 예취시 예취높이가 높아짐에 따라 조단백질 및 조지방함량은 감소하고 조섬유 및 조회분함량은 증가하였으나 NFE 함량은 처리간 차이가 없었다. 3. 청예수량 예취높이 10cm가 다른 처리구보다 많았는데 섬진벼는 4.45ton /ha, KL501은 4.71ton /ha이며 건물수량은 섬진벼가 1.16 ton /ha, KL501이 1.14 ton /ha이었다. 4. TDN함량은 1차 예취시 예취높이가 높을수록 증가하나 2차 예취시는 이와 반대의 경향이며 TDN수량은 예취높이 10cm, 예취시 섬진벼는 0.63ton /ha, KL501은 0.61ton /ha로 다른 처리구보다 많았으나 품종간 차이는 인정되지 않았다.

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피조개, Scapharca broughtonii 외투막 상피층의 미세구조 (Ultrastructure of the Mantle Epidermis in the Ark Shell, Scapharca broughtonii (Bivalvia: Acridae))

  • 이정식
    • Applied Microscopy
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    • 제32권3호
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    • pp.213-222
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    • 2002
  • 피조개의 외투막은 바깥 상피층, 결합조직층 그리고 안쪽 상피층으로 구성되어 있다. 상피층은 단층으로 지지세포, 섬모세포 및 분비세포들로 구성되며, 결합조직층은 주로 교원섬유와 근섬유로 이루어져 있다. 안쪽 상피층의 지지세포들은 원주형으로 자유면은 미세융모로 덮여있다. 섬모세포들은 자유면에 섬모와 미세융모를 가지며, 이들 세포의 세포질 상부에서는 다수의 관상 미토콘드리아들이 관찰된다. 분비세포들은 주로 바깥 상피층에서 관찰되며, 분비과립의 형태학적 특징에 따라 A, B, C, D 네 종류로 구분할 수 있다. A형 분비세포들은 점액세포들로서 가장자리와 중앙부의 외투막에서 주로 관찰되며, 이들 세포의 분비과립은 전자밀도가 낮고 막을 가지지 않는다. B형 분비세포들은 발달된 다수의 조면소포체와 골지체 그리고 전자밀도가 높고 막을 가진 분비과립들을 함유한다. C형 분비세포들의 분비과립은 섬유성분의 중심부와 균질성의 주변부로 구분된다. D형 분비세포들은 주로 중앙부와 각정부 외투막의 바깥 상피층에서 관찰되며, 이들 세포의 분비과립은 균질성의 중심부와 과립상의 주변부로 구분된다. 이와 같은 결과들은 피조개 외투막의 바깥 상피층은 패각형성에 관여하며, 안쪽 상피층은 외투강 정화에 관여함을 의미한다.

Development of Two-Step Temperature Process to Modulate the Physicochemical Properties of β-lactoglobulin Nanoparticles

  • Ha, Ho-Kyung;Nam, Gyeong-Won;Khang, Dongwoo;Park, Sung Jean;Lee, Mee-Ryung;Lee, Won-Jae
    • 한국축산식품학회지
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    • 제37권1호
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    • pp.123-133
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    • 2017
  • The development of a new manufacturing process, a two-step temperature treatment, to modulate the physicochemical properties of nanoparticles including the size is critical. This is because its physicochemical properties can be key factors affecting the cellular uptake and the bioavailability of bioactive compounds encapsulated in nanoparticles. The aims of this study were to produce (beta-lactoglobulin) ${\beta}-lg$ nanoparticles and to understand how two-step temperature treatment could affect the formation and physicochemical properties of ${\beta}-lg$ nanoparticles. The morphological and physicochemical properties of ${\beta}-lg$ nanoparticles were determined using atomic force microscopy and a particle size analyzer, respectively. Circular dichroism spectroscopy was used to investigate the secondary structure of ${\beta}-lg$. The surface hydrophobicity and free thiol groups of ${\beta}-lg$ were increased with a decrease in sub-ambient temperature and an increase in mild heat temperature. As sub-ambient temperature was decreased, a decrease in ${\alpha}-helical$ content and an increase in ${\beta}-sheet$ content were observed. The two-step temperature treatment firstly involved a sub-ambient temperature treatment from 5 to $20^{\circ}C$ for 30 min, followed secondly by a mild heat temperature treatment from 55 to $75^{\circ}C$ for 10 min. This resulted in the production of spherically-shaped particles with a size ranging from 61 to 214 nm. Two-way ANOVA exhibited the finding that both sub-ambient and mild heat temperature significantly (p<0.0001) affected the size of nanoparticles. Zeta-potential values of ${\beta}-lg$ nanoparticles were reduced with increasing mild heat temperature. In conclusion, two-step temperature treatment was shown to play an important role in the manufacturing process - both due to its inducement of the conformational changes of ${\beta}-lg$ during nanoparticle formation, and due to its modulation of the physicochemical properties of ${\beta}-lg$ nanoparticles.