• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.331-336
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• 2001

Aragonite type of precipitated calcium carbonate was synthesized by the successive reaction with hybridization of waste scallop shells with limestone. In the first step, carbonation was performed by using calcined limestone with low brightness, followed by the additional carbonation using calcined-hydrous scallop shells with high brightness. The temperature and the amount ratio of calcined limestone to calcined-hydrous scallop shells were examined as parameters in the experimental conditions. The products were characterized by XRD, SEM. in addition to measurements of brightness index. the specific surface area, and bulk density. The amount ratio of limestone to scallop shell affected not only the brightness but also morphologies of products. The increase in relative amounts of limestone leads to decrease in brightness and bumpy surface of particles. High temperature reaction produces aragonite particles with longer sizes and higher bulk densities. This study has made an attempt to establish the synthesis of aragonite with high brightness and high strength by utilization of waste scallop shells.

• Carbon letters
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• v.6 no.3
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• pp.181-187
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• 2005

Bipolar plates require some specific properties such as electrical conductivity, mechanical strength, chemical stability, and low permeability for the fuel cell application. This study investigated the effects of carbon nanotube (CNT) contents and process conditions of hot press molding on the electrical and physical properties using CNT 3~7 wt% added graphite nano-composites in the curing temperatures range of 140~$200^{\circ}C$ and pressure of 200~300 kg/$cm^2$. Bulk density, hardness and flexural strength increased with increasing CNT contents, curing pressure and temperature. With the 7 wt% CNT added noncomposite, the electrical resistance improved by 30% and the flexural strength increased by 25% as compared to that without CNT at the temperature of $160^{\circ}C$ and pressure of 300 kg/$cm^2$. These properties were close to the DOE reference criteria as bulk resistance of 13 $m{\Omega}cm$ and tensile strength of 515 kg/$cm^2$.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.500-507
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• 2009

Tensile deformation behavior with different strain rate was investigated. $Zr_{56.2}Ti_{13.8}Nb_{5.0}Cu_{6.9}Ni_{5.6}Be_{12.5}$(bulk metallic glass alloy possessed crystal phase which was called $\beta$-phase of dendrite shape, mean size of $20{\sim}30{\mu}m$ and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74GPa at strain rate $10^2s^{-1}$ and minimum strength was found to be 1.6GPa at $10^{-1}s^{-1}$. And then, maximum plastic deformation occurred at the strain rate of $5{\times}10^{-2}s^{-1}$ and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

• Plant Biotechnology Reports
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• v.2 no.4
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• pp.239-243
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• 2008

Simmondsia chinensis (Link) Schneider, a multipurpose and monogeneric dioecious shrub from arid zones, has emerged as a cash crop all over the globe. Its seed propagation poses severe problems due to its male-biased population: the male:female ratio is 5:1. Investigations have been carried out to generate a sex-specific Inter-simple sequence repeat (ISSR) marker for the early detection of male and female plants. Of the 42 primers analysed with a bulk sample of pooled male DNA and a bulk sample of pooled female DNA, only one primer, UBC-807, produced a unique ~1,200 base-pair fragment in the male DNA. To validate this observation, this primer was re-tested with individual male and female samples from eight cultivars. A similar unique ~1,200 bp fragment was present in the male individuals of all eight cultivars and completely absent in the female individuals tested. This is the first report of the use of ISSR markers to ascertain sex in physiologically mature S. chinensis plants.

• Mycobiology
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• v.36 no.1
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• pp.40-44
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• 2008

Various bacteria were isolated from the casing layer soil of the culture bed of P. ostreatus and their role in fruiting body induction of the edible mushroom, P. ostreatus, was investigated. Analysis of the bacterial community isolated from the casing layer soil revealed that the composition of genera and number of cultivable bacteria were different for each sterilizing treatment. Bordetella was predominant in the bulk soil whereas Flavobacterium was predominant after sterilization of the casing layer soil. Fluorescent Pseudomonas was predominant in the non-sterilized casing layer soil. Total number of the bacterial genera in the casing layer soil was higher than that in the bulk soil. In particular, an increase in the fluorescent Pseudomonas population was observed in the non-sterilized casing layer accompanied by induction of fruiting body and enhanced mushroom production yield. The results suggested that specific bacterial populations in the casing layer play an important role in the formation of primodia and the development of basidiome in P. ostreatus.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.353-354
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• 2009

Tensile deformation behavior with different strain rate was investigated. $Zr_{56.2}Ti_{13.8}Nb_{5.0}Cu_{6.9}Ni_{5.6}Be_{12.5}$ (bulk metallic glass alloy possessed crystal phase which was called $\beta$-phase of dendrite shape, mean size of $20{\sim}30{\mu}m$ and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74Gpa at strain rate of $10^2/s$ and minimum strength was found to be 1.6GPa at $10^{-1}/s$. And then, maximum plastic deformation occurred at the strain rate of $5{\times}10^{-2}/s$ and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1048-1049
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• 2006

Rapidly solidified ribbon-consolidation processing was applied for preparation of high strength bulk Mg-Zn-Gd alloys. Mg alloys have been used in automotive and aerospace industries. Rapid solidification (RS) process is suitable for the development of high strength Mg alloys, because the process realizes grain-refinement, increase in homogeneity, and so on. Recently, several nanocrystalline Mg-Zn-Y alloys with high specific tensile strength and large elongation have been developed by rapidly solidified powder metallurgy (RS P/M) process. Mg-Zn-Y RS P/M alloys are characterized by long period ordered (LPO) structure and sub-micron fine grains. The both additions of rare earth elements and zinc remarkably improved the mechanical properties of RS Mg alloys. Mg-Zn-Gd alloy also forms LPO structure in -Mg matrix coherently, therefore, it is expected that the RS Mg-Zn-Gd alloys have excellent mechanical properties. In this study, we have developed high strength RS Mg-Zn-Gd alloys with LPO structure and nanometer-scale precipitates by RS ribbon-consolidation processing. $Mg_{97}Zn_1Gd_2$ and $Mg_{95.5}Zn_{1.5}Gd_3$ and $Mg_{94}Zn_2Gd_4$ bulk alloys exhibited high tensile yield strength (470 MPa and 525 MPa and 566 MPa) and large elongation (5.5% and 2.8% and 2.4%).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.85-107
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• 1993

The cosmetic fine powders were mixed with variation of mixing time(5) in the mixers (ribbon mixer, powder mixer, micropulverizer and fine impact mill). The powders were nixed with small amount of ferric oxide. as tracer. The mixed powders ere measured the particle size distribution, specific surface area and surface color with mixing time (s). The color variation, particle size distribution and specific surface area of the mixed powder exist a relationship with mining time(s) that can be expressed as mathematical equations to show the degree of the mixing of the powder mixture. The linear velocity of the impellar tip is the main factor contributing to he mixing efficiency of the mixers un this study. According to the linear velocity, he mixers used are devieded as convection mixing (ribbon mixer), sclera mixing powder mixer) and diffusion mixing (micropulverizer/fine impact mill).

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.644-648
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• 2002

Though it was difficult of globally monitor latent heat flux aver the ocean for many years, the situation is rapidly changing by the use of satellite data. Since a bulk formula is used to estimate turbulent heat flux using satellite data, we need wind speed, sea surface temperature and specific humidity data. However, it is not easy to accurately estimate specific humidity using satellite data. Now several algorithms for estimating specific humidity have been proposed and applied to construct latent heat flux data sets. Latent heat flux data sets derived from satellite data such as J-OFURO, HOAPS and GSSTF are available at present. Since the algorithm and used satellite data are not the same between them. the characteristics of each data set may be different. Therefore, it is important to clarify the difference between each data set and investigate the cause of the difference in latent heat flux estimates. In this paper we summarize the present state of the art with regard to the turbulent heat flux estimation by using satellite data. Also we present the comparison results of latent heat flux fields including not only satellite-derived flux fields but also analysis fields.

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.635-653
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• 1999

The present work considers work considers research strategies to address global warming. Specifically, this work considers the development of technologies of importance for the reduction of greenhouse gas emission and, especially, the materials that are critical to these technologies. It is argued that novel materials that are essential for the production of environmentally friendly energy may be developed through a special kind of engineering: interface engineering, rather than through classical bulk chemistry. Progress on the interface engineering requires to increase the present state of understanding on the local properties of materials interfaces and interfaces processes. This, consequently, requires coordinated international efforts in order to establish a strong background in the science of materials interfaces. This paper considers the impact of interfaces, such as surfaces and grain boundaries, on the functional properties of materials. This work provides evidence that interfaces exhibit outstanding properties that are not displayed by the bulk phase. It is shown that the local interface chemistry and structure and entirely different than those of the bulk phase. In consequence the transport of both charge and matter along and across interfaces, that is so important for energy conversion, is different than that in the bulk. Despite that the thickness of interfaces is of an order to a nanometer, their impact on materials properties is substantial and, in many cases, controlling. This leads to the conclusion that the development of novel materials with desired properties for specific industrial applications will be possible through controlled interface chemistry. Specifically, this will concern materials of importance for energy conversion and environmental monitoring. Therefore, there is a need to increase the present state of understanding of the local properties of materials interfaces and the relationship between interfaces and the functional properties of materials. In order to accomplish this task coordinated international efforts of specialized research centres are required. These efforts are specifically urgent regarding the development of materials of importance for the reduction of greenhouse gases. Success of research in this area depends critically on financial support that can be provided for projects on materials of importance for a sustainable environment, and these must be considered priorities for all of the global economies. The authors of the present work represent an international research group economies. The authors of the present work represent an international research group that has entered into a collaboration on the development of the materials that are critical for the reduction of greenhouse gas emissions.