• Fisheries and Aquatic Sciences
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• 제8권1호
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• pp.1-5
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• 2005

Cell growth of the marine microalga Tetraselmis suecica was regulated by the addition of seaweed extracts in its culture medium. Of 26 species of seaweed tested, water-soluble extracts from Monostroma nitidum and Pachymeniopsis elliptica and methanol-soluble extract from Sargassum confilsum enhanced the growth of T suecica cells. The water extract of M. nitidum was the most effective, producing up to a 2-fold increase in cell density with the addition of 1 mg/mL of extract to the culture medium. Cell size, gross biochemical composition, fatty acids, and digestion efficiency all differed marginally between cultures of T suecica grown with and without the M. nitidum extract.

• 한국기계가공학회지
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• 제10권5호
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• pp.58-64
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• 2011

In this paper, research on the manufacturing technology of hexagonal structure core is investigated. Also the optimal forming process of the honeycomb core is developed and the rolling process is analyzed using finite element code, $DEFORM^{TM}$-3D. The standard honeycomb has a uniform hexagonal structure defined by the material, cell size, cell wall thickness and bulk density. Honeycomb core products can be made from any thin, flat material. The most common cell configuration is the hexagon but there are many other shapes for special applications. Because of the precision shape and the thin thickness, the honeycomb core is not easy to manufacture in the metal forming process. Through this study it was confirmed that after the rolling process, the section of honeycomb close to the standard shape can be obtained. This result is reflected to the manufacturing process design for the honeycomb core.

• 한방재활의학과학회지
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• 제19권1호
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• pp.91-102
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• 2009

Objectives : The present study was carried out investigate the anti-cancer effect of Salvia miltiorrhiza, Carydalis turtschaminovii and Reynoutria elliptica herbal acupuncture on solid tumor of rats induced by injection of RK3E-ras cells. Methods : RK3E-ras cells were injected on the right lumbar region of rats. After 1 weeks, the experimental rats were divided into four groups : Control group, Salvia miltiorrhiza herbal acupuncture group(SM), Carydalis turtschaminovii herbal acupuncture group(CT), Reynoutria elliptica herbal acupuncture group(RE). And we investigated the weight and size of tumor tissue, gross anatomy, histological and PCNA immunohistochemical study, hepatic and renal metastasis for tumor of each group. Results : 1. In the weight of tumor tissue assessment, SM and CT's weight of tumor tissue was decreased. 2. In the size of tumor tissue assessment, SM was smaller than any other group. 3. In the histological observation, SM's formation of tunica fibrosa that surround the tumor cell was obvious and vasculature that developes circumference of tumor cell was not observed, and density of tumor cell was very low. 4. In the PCNA immunohistochemical study, Control group, SM, RE showed strong immune response in the central site of tumor tissue. 5. In observation of liver and kidney tissue, we were not able to observe tumor cell in the SM. Conclusions : Consequently, SM and CT showed a inhibition of growth and metastasis.

• Applied Microscopy
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• 제22권1호
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• pp.15-32
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• 1992

This study was an attempt to investigate and compare the fine structure of small cells in the space of Disse of various animal livers. All animal livers contained small cells with or without lipid droplets and the one with lipid droplet seemed to be more developed and show an abundance of activity in function. The fine structure of the small cells observed in the nonmammals was similar to that of Ito cell in the mammal. The electron density of the small cells was similar to that of other cell types in the same animal liver. The cisternal dilation of rough endoplasmic reticulum and Golgi apparatus was more predominant in the mammalian Ito cells. In the nonmammalian, aquatic vertebrates, however, lysosomes and filaments are much more abundant in the Ito cell and its abundant cytoplasmic processes rich in filaments were usually extended between the parenchymal cells. The disparity in size of organelles and numbers of lipid droplets in the small cells showed a tendency similar to those of other cell types in the same animal. From these results, it is considered that the small cells in the space of Disse is a Ito cell and the Ito cell without lipid droplets differentiates into the one containing lipid droplets according to the characteristics of the different animals respectively, and that the Ito cells in the mammals are more active in metabolic function, while those in the nonmammalian aquatic vertebrates are abundant in support of parenchyme.

• Current Photovoltaic Research
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• 제9권4호
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• pp.123-127
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• 2021

This study was on electrode design for the realization of a solar cell that combines electrode formation and module integration process to overcome printing limitations. We used the passivated emitter rear contact (PERC) solar cell. Wafer size was 156.75 mm ×156.75 mm. The fabricated cell results showed that the open-circuit voltage of 649 mV, short-circuit current density of 36.15 mA/cm², fill factor of 68.5%, and efficiency of 16.06% with electrode conditions the 24BBs with the width 190 ㎛ and 90FBs with the width 45 ㎛. For improving efficiency, the characteristics of the solar cell were checked according to the change in the number of BBs and FBs and the change in line fine width. It is confirmed that the efficiency of the solar cell will be improved by increasing the number of FBs from 90 to 120, and increasing the line width of the FBs by about 10 ㎛ compared to the manufacturing solar cells.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1367-1370
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• 2005

Microcellular foam processing of polymers requires a nucleated cell density greater than $10^9\;cells/cm^3$ so that the fully grown cells are smaller than 10 mm. A microcellular foam can be developed by first saturating a polymer sample with a volatile blowing agent, followed by rapidly decreasing its solubility in the polymer. In general, the cellular structure of crystalline polymer foams is difficult to control, compared to that of amorphous polymer foams. Since the gas does not dissolved in the crystallites, the polymer/gas solution formed during the microcellular processing is nonuniform. Moreover, the bubble nucleation is nonhomogeneous because of the heterogeneous nature of the crystalline polymer. In this paper, the effects of the crystallinity and morphology of crystalline polymers on the microcellular foam processing and on reflectivity of products are investigated. First, polymer specimens with various morphology and amount of solved blowing agent were prepared by varying the saturation pressure, saturation time and foaming condition. Then, cell morphologies according to several conditions were studied. The specimens with differing gas amount of solved and morphologies were foamed and their cellular structures were compared. The experimental results of reflectivity are compared to raw specimen and another specimen of different experimental conditions. After the experiments, recognize whether how reflectivity changes according to solved gas amount. And the effect of cell density and cell size on reflectivity is studied

• 한국분말재료학회지
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• 제23권2호
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• pp.136-142
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• 2016

As precursors of cathode materials for lithium ion batteries, $Ni_{1/3}Co_{1/3}Mn_{1/3}(OH)_2$ powders are prepared in a continuously stirred tank reactor via a co-precipitation reaction between aqueous metal sulfates and NaOH in the presence of $NH_4OH$ in air or nitrogen ambient. Calcination of the precursors with $Li_2CO_3$ for 8 h at $1,000^{\circ}C$ in air produces dense spherical cathode materials. The precursors and final powders are characterized by X-ray diffraction (XRD), scanning electron microscopy, particle size analysis, tap density measurement, and thermal gravimetric analysis. The precursor powders obtained in air or nitrogen ambient show XRD patterns identified as $Ni_{1/3}Co_{1/3}Mn_{1/3}(OH)_2$. Regardless of the atmosphere, the final powders exhibit the XRD patterns of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ (NCM). The precursor powders obtained in air have larger particle size and lower tap density than those obtained in nitrogen ambient. NCM powders show similar tendencies in terms of particle size and tap density. Electrochemical characterization is performed after fabricating a coin cell using NCM as the cathode and Li metal as the anode. The NCM powders from the precursors obtained in air and those from the precursors obtained in nitrogen have similar initial charge/discharge capacities and cycle life. In conclusion, the powders co-precipitated in air can be utilized as precursor materials, replacing those synthesized in the presence of nitrogen injection, which is the usual industrial practice.

• 전기전자학회논문지
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• 제5권1호
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• pp.43-51
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• 2001

메모리의 집적도가 올라갈수록 원치 않는 셀간의 간섭과 동시에 bit-line간의 상호 노이즈도 증가하게 된다. 그리고 높은 고장 검출율을 요구하는 고집적 메모리의 테스트는 많은 테스트 백터를 요구하게 되거나 비교적 큰 추가 테스트 회로를 요구하게 된다. 지금까지 기존의 테스트 알고리즘은 이웃 bit-line의 간섭이 아니라 이웃 셀에 중점을 두었다. 본 논문에서는 NPSFs(Neighborhood Pattern Sensitive Faults)를 기본으로 한 NBLSFs(Neighborhood Bit-Line Sensitive Faults)를 위한 새로운 테스터 알고리즘을 제안한다. 그리고 제안된 알고리즘은 부가 회로를 요구하지 않는다. 메모리 테스트를 위해 기존의 5개의 셀 레이아웃이나 9개의 셀 레이아웃을 사용하지 않고 NBLSF 검출에 최소한 크기인 3개의 셀 레이아웃을 이용하였다. 더구나 이웃 bit-line에 의한 최대의 상호잡음을 고려하기 위해 테스트 동작에 refresh 동작을 추가하였다(예 $write{\rightarrow}\;refresh{\rightarrow}\;read$). 또한 고착고장, 천이고장, 결합고장, 기존의 pattern sensitive 고장, 그리고 이웃 bit-line sensitive 고장 등도 검출될 수 있음을 보여준다.

• Carbon letters
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• 제14권1호
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• pp.40-44
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• 2013

The bipolar plate is the most important and most costly component of proton exchange membrane fuel cells. The development of a suitable low density bipolar plate is scientifically and technically challenging due to the need to maintain high electrical conductivity and mechanical properties. Here, bipolar plates were developed from different particle sizes of natural and expanded graphite with phenolic resin as a polymeric matrix. It was observed that the particle size of the reinforcement significantly influences the mechanical and electrical properties of a composite bipolar plate. The composite bipolar plate based on expanded graphite gives the desired mechanical and electrical properties as per the US Department of Energy target, with a bulk density of 1.55 $g.cm^{-3}$ as compared to that of ~1.87 $g.cm^{-3}$ for a composite plate based on natural graphite (NG). Although the bulk density of the expanded-graphite-based composite plate is ~20% less than that of the NG-based plate, the I-V performance of the expanded graphite plate is superior to that of the NG plate as a consequence of the higher conductivity. The expanded graphite plate can thus be used as an electromagnetic interference shielding material.

• 신재생에너지
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• 제3권1호
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• pp.60-67
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• 2007

Catalyst coated membrane [CCM] type and catalyst coated substrate [CCS] type of membrane electrode assembly [MEA] were manufactured and evaluated their performance. Degradation test were conducted to find the difference of long term stability in two types of MEA and the factor for performance degradation problem occurred. Performance degradation test of single cell in two different types of MEA were carried out when current density was $200mA/cm^{2}$. The degradation test had proceeded for 230 hours and performance degradation was checked by I-V curve and impedance measurement at regular intervals. Also, MEA before/after operation and changes of catalyst layer were characterized by SEM, TEM, and XRD. Maximum power density of CCM type was higher than that of CCS type. Meanwhile, an increase of particle size of catalyst and an increase of impedance resistance after long term operation were observed. In the case of using CCM type MEA, the performance was deteriorated 38% of initial performance. In the case of using CCS type MEA, the performance was deteriorated 43% of initial performance. In consideration of difference of initial performance, performance of CCM type is higher than that of CCS type but both types had similar problems during degradation test.