• Fisheries and Aquatic Sciences
• /
• v.8 no.1
• /
• pp.1-5
• /
• 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.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.5
• /
• pp.58-64
• /
• 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.

• Journal of Korean Medicine Rehabilitation
• /
• v.19 no.1
• /
• pp.91-102
• /
• 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
• /
• v.22 no.1
• /
• pp.15-32
• /
• 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
• /
• v.9 no.4
• /
• pp.123-127
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1367-1370
• /
• 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

• Journal of Powder Materials
• /
• v.23 no.2
• /
• pp.136-142
• /
• 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.

• Journal of IKEEE
• /
• v.5 no.1 s.8
• /
• pp.43-51
• /
• 2001

As the density of memories increases, unwanted interference between cells and coupling noise between bit-lines are increased. And testing high-density memories for a high degree of fault coverage can require either a relatively large number of test vectors or a significant amount of additional test circuitry. So far, conventional test algorithms have focused on faults between neighborhood cells, not neighborhood bit-lines. In this paper, a new test algorithm for neighborhood bit-line sensitive faults (NBLSFs) based on the NPSFs(Neighborhood Pattern Sensitive Faults) is proposed. And the proposed algorithm does not require any additional circuit. Instead of the conventional five-cell or nine-cell physical neighborhood layouts to test memory cells, a three-cell layout which is minimum size for NBLSFs detection is used. Furthermore, to consider faults by maximum coupling noise by neighborhood bit-lines, we added refresh operation after write operation in the test procedure(i.e.,$write{\rightarrow}\;refresh{\rightarrow}\;read$). Also, we show that the proposed algorithm can detect stuck-at faults, transition faults, coupling faults, conventional pattern sensitive faults, and neighborhood bit-line sensitive faults.

• Carbon letters
• /
• v.14 no.1
• /
• pp.40-44
• /
• 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.

• New & Renewable Energy
• /
• v.3 no.1 s.9
• /
• pp.60-67
• /
• 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.