• 제목/요약/키워드: Cell size and density

검색결과 380건 처리시간 0.031초

압출성형기의 스크류 회전속도와 원료수분함량이 대두단백질의 조직화에 미치는 영향 (The Effects of Screw Speeds and Moisture Contents on Soy Protein under Texturization Using a Single-screw Extruder)

  • 한억;이상효;이현유;오상룡;이철호
    • 한국식품과학회지
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    • 제21권6호
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    • pp.772-779
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    • 1989
  • 분리대두단백의 조직화에 대한 스크류 회전속도와 원료 수분함량의 영향을 조사하였다. 수분함량이 증가함에 따라 토출구온도는 감소하였으며 210rpm에서 가장 높은 온도를 나타내었다. 수용성 질소지수는 수분함량이 증가할수록 감소하였으며 고속보다는 저속에서 감소폭이 컸다. 조직잔사지수는 낮은 수분함량과 고속 rpm에서 높게 나타났으며 조직감의 강도는 이와 반대의 경향이었다. 또한 원료의 수분함량이 증가할수록 최종 압출성형물의 수분함량이 증가하였고 고속 rpm일수록 낮은 수분함량을 나타내었다. 밀도의 경향도 이와 일치하였다. 재흡수력의 경우는 수분함량 30%에서 최고치를 나타내었으며 고속 rpm에서 증가하였다. 복원전의 명초는 복원 후 보다 높은 수치를 보였고 고속회전일 수록 명도가 밝아졌다. 성상에 있어서도 저수분, 고속 rpm에서 높은 명도와 높은 정화도가 관찰되었다. 분산분석을 통해서 스크류 회전속도보다 원료의 수분함량이 조직화 성질을 나타내는 각 지표에 더 깊은 영향을 주는 것으로 확인되었다.

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$\beta$-Cyclodextrin Reduces Obesity in C57BL/6J Mice Induced by High Fat Diet

  • Kim, Dae-Won;Hwang, In-Koo;Yoo, Ki-Yeon;Li, Hua;Pai, Tong-Kun;Kim, Young-Sup;Kwon, Dae-Young;Kim, Dong-Woo;Moon, Won-Kuk;Won, Moo-Ho
    • Food Science and Biotechnology
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    • 제17권4호
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    • pp.700-704
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    • 2008
  • Anti-obesity effects of $\beta$-cyclodextrin in obese C57BL/6J mice induced by a high fat diet (HD) were observed. The administration of $\beta$-cyclodextrin reduced the gain of body weight, abdominal fat, liver weight, the lipid deposits of hepatocytes and the size of adipocytes in the HD group. In serum analysis, the total and low-density lipoprotein-cholesterols were significantly decreased in the $\beta$-cyclodextrin-supplemented HD group than in the HD group. However, high-density lipoprotein-cholesterol was not changed in these groups. In hypothalamic homogenates, the decrease of neuropeptide Y and increase of $\alpha$-melanocyte stimulating hormone were detected in the $\beta$-cyclodextrin-supplemented HD group compared to that in the HD group. These effects of $\beta$-cyclodextrin were similar to those of Garcinia cambogia, which is widely used as a natural anti-obesity product. These results suggest that $\beta$-cyclodextrin has anti-obesity effects through the lowering of the abdominal fat pad and inhibits the central effects of hunger.

연료극 지지체식 평관형 고체산화물 연료전지 특성 연구 (Characteristics of Anode-supported Flat Tubular Solid Oxide Fuel Cell)

  • 김종희;송락현
    • 전기화학회지
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    • 제7권2호
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    • pp.94-99
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    • 2004
  • 연료극 지지체 평관형 고체산화물 연료전지(SOFC)의 셀 전력밀도를 증가시키기 위하여 압출법에 의하여 제조하고 그 특성을 연구하였다. 연료극 지지체로써 Ni/YSZ($8mol\%$ yttria stabilized zirconia) cermet는 기공율 $50.6\%,\;0.23{\mu}m$의 기공크기를 나타내었다. 지지체에서의 Ni의 분포는 균일하였으며 전자전도 경로로써의 Ni의 연결성은 양호하였다. 지지체에 YSZ전해질과 복합 공기극층인 $LSM((La_{0.85}Sr_{0.15})_{0.9}MnO_3)/YSZ$ 복합층, LSM, LSCF $(La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3)$층이 슬러리 디핑법에 의하여 코팅 및 소결된 연료극 지지체식 평관형 고체산화물 연료전지 단위전지의 성능은 $800^{\circ}C$에서 $300mW/cm^2(0.6V,\;500mA/cm^2)$의 성능을 나타내었다. 임피던스 분석에 의하여 평관형 셀의 전기화학적 분극저항을 평가하고 연료측의 가습에 따라 분극저항이 감소되어 성능이 향상됨을 알 수 있었다 슬러리 디핑법으로 LSM이 코팅된 SUS430 금속연결재를 $Ar+10\%\;H_2$에서 소결하였으며, $750^{\circ}C$에서 면저항의 측정할 결과, 초기에는 $148m{\Omega}cm^2$를 나타내었으며, 450시간 경과 후에 $43m{\Omega}cm^2$의 낮은 면저항을 유지하였다. 반면에 동일한 조건으로 LSM이 코팅된 Fecralloy는 높은 면저항을 나타내었다.

폴리에틸렌옥사이드 하이드로겔을 이용한 도네페질염산염의 이온토포레시스 피부투과 (Electrotransport of Donepezil Hydrochloride from Poly(ethylene oxide) Hydrogel)

  • 최유리;오승열
    • Journal of Pharmaceutical Investigation
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    • 제40권2호
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    • pp.91-100
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    • 2010
  • The objective of this work is to study transdermal delivery of donepezil hydrochloride (DH) using iontophoresis and to evaluate various factors which affect the transdermal transport. After the flux study using 4 kinds of hydrogel, hydrogel containing 8% poly(ethylene oxide) (PEO) was chosen as the hydrogel for further studies. Under experimental condition, DH was stable. We have studied the effect of polarity, current density, drug concentration and current profile on transdermal flux and compared the results. In vitro flux study was performed at $33^{\circ}C$, using side-by-side diffusion cell and full thickness hairless mouse skin. DH is positively charged at pH 7.4, and anodal delivery was much larger than cathodal and passive delivery at all current densities studied (0.2, 0.4 and 0.6 mA/$cm^2$). Cathodal delivery showed higher flux than passive flux. Flux increased as the concentration of DH in hydrogel increased. Pulsatile application of current showed smaller flux value than the application of continuous current. Based on these results, we have evaluated the possibility of delivering enough amount of DH to reach the therapeutic level. The maximum cumulative amount of DH transported for 12 hours was 455 ${\mu}g/cm^2{\cdot}hr$ when the amount of DH in the hydrogel was 3 mg/mL and the current density was 0.4 mA/$cm^2$. If the patch size is 10 $cm^2$, then we can deliver 4.6 mg for 12 hours. Because the daily dosage of DH is 5 mg, it seems possible to deliver clinically effective amount of DH using iontophoresis. This study also provides some information about the role of electrorepulsion and electroosmosis during the transport through skin.

Non-linear Resistive Switching Characteristic of ZnSe Selector Based HfO2 ReRAM Device for Eliminating Sneak Current

  • 김종기;김영재;목인수;이규민;손현철
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.357-358
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    • 2013
  • The non-linear characteristics of ON states are important for the application to the high density cross-point memory industry because the sneak current in neighbor cells occurred during reading, erasing, and writing process. Kw of above 20 in ON states, which is the writing current @ Vwrite/the current @ 1/2Vwrite, was required in cross-point ReRAM memory industry. The high current density non-linear IV curve of ZnSe selector was shown and the ALD HfO2 switching device has the linear properties of ON states and the compliance current of 100 uA. To evaluate the performance of the selection device, we connected itto HfO2 switching device in series. The bottom electrode of the selection device was connected to the top electrode of the RRAM. All of the bias was applied with respect to the top electrode of the selection device, whereas the bottom electrode of the RRAM was grounded. In the cross-point application, 1/2Vwrite and -1/2Vwrite were applied to the word-line and bit-line, respectively, which were connected to the selected cell, and a zero bias was applied to the unselected word-lines and bit-lines. The current @ 1/2Vwrite of the unselected cells was blocked by the selection device, thus eliminating the sneak path and obtaining a writing voltage margin. Using this method, the writing voltage margin was analyzed on the basis of the memory size.

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Synthesis and Characterization of PtPd and PtRuPd Anode Catalysts for Direct Methanol Fuel Cells

  • Horvath G.;Park K. W.;Sung Y. E.
    • 한국전기화학회:학술대회논문집
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    • 한국전기화학회 2002년도 연료전지심포지움 2002논문집
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    • pp.211-218
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    • 2002
  • In this study, Pt/Pd (1.1), PtPd (2:1) and PtPd (3:1) binary catalysts and Pt/Ru/Pd (5:4:1) ternary catalyst were designed. The catalysts were synthesized by impregnation method using $NaBH_4$ as a reducing agent. A good catalyst for methanol oxidation requires low on-set potential, stable durability and low activation energy. In order to investigate the catalytic activity for the methanol oxidation, electrochemical measurements such as cyclic voltammetry and chronoamperometry were peformed in sulfuric acid with/without methanol solution. In order to calculate the activation energy of the reaction, electrochemical measurements were also tested at different temperatures. For investigation of the structural analysis such as particle size and alloying, X-ray diffraction and transmission electron microscopy analysis were used. In order to identify the role of the Pd and to determine the composition of the surface of the Pt/Pd nanoparticles, X-ray photoelectron spectroscopy (XPS) analysis was investigated. The XPS spectra of Pd showed that Pd appears only as a metallic state in the binary catalysts. The chemical states of Pt in PtPd catalysts are both metallic and oxidative. Polarization curves and power density data were obtained by testing the DMFC unit cell performance of PtPd and PtRuPd catalysts. These data showed that Pt/Pd (2:1) and Pt/Ru/Pd (5:4:1) have better performance than Pt and Pt/Ru, respectively.

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A Novel Dual-Input Boost-Buck Converter with Coupled Inductors for Distributed Thermoelectric Generation Systems

  • Zhang, Junjun;Wu, Hongfei;Sun, Kai;Xing, Yan;Cao, Feng
    • Journal of Power Electronics
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    • 제15권4호
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    • pp.899-909
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    • 2015
  • A dual-input boost-buck converter with coupled inductors (DIBBC-CI) is proposed as a thermoelectric generator (TEG) power conditioner with a wide input voltage range. The DIBBC-CI is built by cascading two boost cells and a buck cell with shared inverse coupled filter inductors. Low current ripple on both sides of the TEG and the battery are achieved. Reduced size and power losses of the filter inductors are benefited from the DC magnetic flux cancellation in the inductor core, leading to high efficiency and high power density. The operational principle, impact of coupled inductors, and design considerations for the proposed converter are analyzed in detail. Distributed maximum power point tracking, battery charging, and output control are implemented using a competitive logic to ensure seamless switching among operational modes. Both the simulation and experimental results verify the feasibility of the proposed topology and control.

휴안포자(Cyst)를 형성하는 과편모조류에 의한 적조발생 (Coastal Algal Blooms Caused by the Cyst-Forming Dinoflagellates)

  • 김학균;박주석;이삼근
    • 한국수산과학회지
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    • 제23권6호
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    • pp.468-474
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    • 1990
  • 휴안포자를 형성하는 과편모조류중 우리나라 남해동부와 동해남부의 연안수역 특히 진해만에서 1982년 이래 3월부터 9월에 걸쳐 적조를 일으킨 종은 8종이었으며 이들은 6종의 과편모조류와 2종의 녹색편모조류로 구성되었다. 계절별로는 이른 봄철에 Scrippsiella trochoidea와 Heterocapsa triquetra종이, 늦봄에 Heterosigma akashiwo가 그리고 여름철에는 Gyrodinium instriatum과 Pheopolykrikos hartmannii가 적조를 일으켰다. 한편 Cochlodinium sp.와 Alexandrium affine는 늦여름부터 가을철에 적조를 일으켰다. 이중 Heterosigma akashiwo는 매년 같은 곳에서 같은 시기에 발생하는 경향을 뚜렷히 나타냈으며 Cochlodinium sp.에서도 이와 같은 특성을 발견할 수 있었다. 한편 적조발생시의 밀도는 $10^3\~10^5\;cells/ml$ 수준이었으며, 밀도변화는 환경특성 보다는 오히려 세포의 크기에 따라 변화하고 있었다.

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Deubiquitinase YOD1: the potent activator of YAP in hepatomegaly and liver cancer

  • Kim, Youngeun;Jho, Eek-hoon
    • BMB Reports
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    • 제50권6호
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    • pp.281-282
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    • 2017
  • Advances in the understanding of the Hippo signaling as a key regulatory pathway of proliferation and apoptosis have provided mechanical insights for controlling organ size and tumorigenicity. Recently, much attention has been directed to the regulation of LATS1/2 (large tumor suppressor) kinases that phosphorylate YAP/TAZ, a transcriptional co-activator in the Hippo pathway, and control the level and nuclear localization of YAP/TAZ. In our recent work, we showed that deubiquitinase YOD1 stabilizes ITCH, and facilitates ITCH-mediated LATS1/2 ubiquitination and degradation, resulting in increased YAP/TAZ level. Furthermore, we found that the YOD1-ITCH-LATS1/2-YAP/TAZ signaling axis is controlled by the differential expression of miR-21 in a cell-density-dependent manner. Using a transgenic mouse model, we showed that the inducible expression of YOD1 enhances the proliferation of hepatocytes and leads to hepatomegaly in a YAP/TAZ-activity-dependent manner. Moreover, a strong correlation was observed between YOD1 and YAP expression in liver cancer patients. Overall, our data suggest that YOD1 is a novel regulator of the Hippo pathway, and thereby a potential therapeutic target for liver cancer.

셀 다공구조를 갖는 Al2O3세라믹스의 제조 (Processing of Al2O3 Ceramics with a Porous Cellular Structure)

  • 임병구;이락형;하정수
    • 한국세라믹학회지
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    • 제44권10호
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    • pp.574-579
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    • 2007
  • Porous $Al_2O_3$ ceramics were prepared by the gelcasting foams method (a slurry foaming process) with acrylamide monomer. The foaming and gelation behavior was investigated with the parameters such as the type and concentration of surfactant, solid loading of slurry, and the concentrations of initiator and catalyst. Density, porosity, microstructure, and strength of the green and sintered samples were characterized. Of the four kinds of surfactants tested, Triton X-114 showed the highest foaming ability for the solid loading of 55-30 vol%. The gelation condition giving the idle time off min was found to set the foamed structure without significant bubble enlargement and liquid lamella thinning. The green samples were fairly strong and machinable and showed maximum strength of 2.4 MPa in diametral compression. The sintered samples showed densities of 10-36% theoretical (i.e. porosity 90-64%) with a highly interconnected network of spherical pores with sizes ranging from 30 to $600{\mu}m$. The pore size and connectivity increased but the cell strut thickness decreased with decreasing the solid loading. Flexural strength of 37.8-1.7 MPa was obtained for the sintered samples.