• Journal of the Korean Magnetics Society
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• v.8 no.2
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• pp.86-92
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• 1998

Homegeneous feedstock is necessary to make plastic magents with uniform magnetic properties, therefore the optrimized mixing route and the homogeneity evaluation method are demanded. In this paper, method of homogeneity evaluation and effect of homogeneity on the magnetic prperites were investigated using Sr-ferrite /EVA plastic magnets. The feedstocks with different homogeneity were prepared using batch mixer and single screw extruder. The homogeneities of feedstocks were tested by torgue sensor, capilary rheometer, and measurement of magnetic properties. Mixing torque measurement using torque sensor was an effective method to determine the critical powder loading, but it was nor suitable to suitable to determine the feedstock mixing quality. Particle alignment measurement of a plastic magent was very accurate to evaluate the homogeneity, but expensive equipments were required to make and measure the samples. Pressure measurement using capillary rheometer was a very effective and easy method with high accuracy. Homogeneous feedstock increased the particle alignment of plastic magnet. Remanet flux density and maximum energy product increased linearly and quadratically with increasing particle alignment, respectively.

• Journal of Korea Technology Innovation Society
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• v.13 no.4
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• pp.700-716
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• 2010

This paper examines the development of smelting reduction process in POSCO from 1990 to 2007 with the perspective of post catch-up technological innovation. POSCO paid attention to smelting reduction process as a sort of next-generation iron and steel technology, and implemented COREX (coal ore reduction) by the cooperation with V$\"{o}$oest. In addition to this, POSCO started to develop FINEX (fine iron ore reduction) which can use abundant powder ore, and FINEX was developed through model plant, pilot plant, demo plant, and commercial facility. POSCO came up to innovation leader beyond fast follower by securing almost technologies concerning FINEX. The case of smelting reduction process shows various characteristics including appropriate technological choice, successive scale-up, spiral development system, complementary technological cooperation, long-tenn investment, the existence of top management's leadership, and Korean government's support in early stage. This case can be interpreted as a path-revealing innovation in the middle of technological paradigm change.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1367-1375
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• 2018

Silver nanoparticles have been widely applied for biomedical areas owing to their potent antiviral and antibacterial activities. Synthesis of silver nanoparticles using biomacromolecules is more efficient, environment-friendly, and cost-saving compared with the traditional approach. In this paper, a novel approach was developed to establish a reaction system with $Ag^+-BH4^--sericin$ to synthesize silver nanoparticles conjugated to sericin (AgNPs-Sericin). Sericin could be as a good dispersant and stabilizing agent, which is able to modify nanoscaled AgNPs, the average diameter of which was only $3.78{\pm}1.14nm$ prepared in a 0.3 mg/ml sericin solution. The characterizations of the AgNPs-Sericin were determined by FTIR, thermogravimetry, and XRD analyses. The results showed that the synthesized AgNPs conjugated with sericin as organic phase. Via SAED and XRD analysis, we showed that these AgNPs formed polycrystalline powder with a face-centered cubic structure of bulk metals. Moreover, we investigated the antiviral and antibacterial activities of AgNPs-Sericin, and the results showed that AgNPs-Sericin exhibited potent anti-HIV-1 activity against CCR5-tropic and CXCR4-tropic strains, but no significant cytotoxicity was found toward human genital epithelial cells compared with free silver ions, which are accepted as a commonly used potent antimicrobial agent. Moreover, its antibacterial activity was determined via flow cytometry. The results showed that AgNPs-Sericin could suppress gram-negative (E. coli) and gram-positive (S. aureus) bacteria, but more was potent for the gram-negative one. We concluded that our AgNPs-Sericin could be a potential candidate as a microbicide or antimicrobial agent to prevent sexually transmitted infections.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.275-282
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• 2002

High fluidity concrete needs high dosage of superplasticizer to acquire sufficient fluidity and high contents of fine powder and viscosity agents to prevent segregation. But it requires high manufacturing cost and has difficult in quality control. Therefore, in this paper, determination of optimal mixture proportion of segregation type superplasticizer for high fluidity concrete and manufacturing high fluidity concrete by applying developed segregation reducing type superplasticizer are discussed using flowing concrete method. According to test results, as dosage of superplasticizer increases, it shows that fluidity and bleeding increase, while air contents and ratio of segregation resistance decrease. It also shows that adding viscosity agent into it reduce bleeding and improve segregation resistance. Dosage of AE agent into it containing viscosity agent recovers loss of air contents during flowing procedure. Combination of proper contents of superplasticizer, viscosity agent and AE agent make possible to develope segregation reducing type superplasticizer Compressive strength of high fluidity concrete applying flowing method with it is higher than that of base concrete. No differences of compressive strength between compacting methods are found.

• Elastomers and Composites
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• v.44 no.3
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• pp.290-298
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• 2009

In this paper, the Fe-activated carbon fiber (ACF)/$TiO_2$ composite catalysts were prepared by a sol-gel method. The synthesized photocatalysts were used for the photo degradation of Methylene blue solution under UV light. From Brunauer-Emmett-Teller measurements (BET) data, it was shown the blocking of the micropores on the surface of ACF by treatment of Fe and Ti compound. As shown in SEM images, the ferric compounds and titanium dioxides were fixed onto the ACF surfaces. The result of X-ray powder diffraction showed that the crystal phase contained a mixing anatase and rutile structure and the 'FeO+$TiO_2$' from the composites. The EDX spectra for the elemental analysis showed the presence of C, O, and Ti with Fe peaks. Degradation activity of MB could be attributed to +OH radicals derived from electron/hole pair's reactions due to photolysis of $TiO_2$ and photo-Fenton effect of Fe.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.1-11
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• 2003

Chinese herbs have been used for a long period of time and less side effects than synthesized chemical drugs. Therefore, using Chinese herbs as natural additives in cosmetics becomes popular in recent years. The methanol extracts of Scutellariae Radix, Lithospermi Radix, Lonicerae Flos, Andrographitis. Herba, Angelicae Dahuricae Radix, Ligustici Rhizoma et Radix, Hedyotis Diffusae Herba, Isatidis Folium, Magnoliae Liliflorae Flos, Forsythiae Fructus, Anmarrhenae Rhizoma, Spirodelae Herba, Gardeniae Fructus, Sophorae Flavescentis Radix, Coptidis Rhizoma, Prunellae Spica, Equiseti Hiemalis Herba, Gentianae Radix, Moutan Radicis Cortex, Fraxini Cortex, Lycii Radicis Cortex, Violae Herba, Lophatheri Herba, Matricariae chamomillae Flos, Taraxaci Herba and Scutellariae Barbatae Herba are used to test the efficiency of inhibiting acne pathogens. Twenty-six Chinese herbs are extracted by methanol, and then condensed to dried powder. These extracts are divided into water-soluble part and DMSO soluble part. These two type solutions are tested for the effect on acne pathogens by paper disc diffusion method. The results show that the substances of water soluble part which are Coptidis Rhizoma, Moutan Radicis Cortex, Scutellariae Barbatae Herba have medium to high activity of inhibiting acne pathogents, and the substances of DMSO soluble part which are Coptidis Rhizoma, Ligustici Rhizoma et Radix, Sophorae Flavescentis Radix, Moutan Radicis Cortex, Scutellariae Radix, Scutellariae Barbatae Herba also have medium to high activity of inhibiting acne pathogens. Using Chinese herbs as natural additives in cosmetics is convenience and valuable application in cosmetceutical research and development. Therefore, it is worth that re-investigation and find out the potential of Chinese herbs being use in cosmetics.

• The Journal of Dong Guk Oriental Medicine
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• v.5
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• pp.231-271
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• 1996

Obstetrics and Gynecology include gynecology which is concerned with the treatment for the disease based on physiology and pathology of women, and obstetrics which is concerned with pregnancy delivery. These obstetics and gynecology can be said to date from the birth of human beings. This paper has carried on the studies about the generating and developing process of obstetics and gynecology. The results of this study are as follows : Distinction in Northern and Southern Dynasties were much more Obstetrics and Gynecology studying the Obstetrics and Gynecology books in that time, the study about "oncosis" (腫瘤) and forms of drug, pill, powder, pIaster were carried on. The highest distinction in Sui age were research and development on pathogenesis and cause of disease about Obstetrics and Gynecology disease and it was appeared representatively in "Zhubingyuanhoulun""諸病源候論" which was special book on cause of disease and pathogenesis and syndrome, And it was explained about abnormal vaginal discharge in this book. Obstetrics and Bynecology were developed on theory and clincis in Tang age when "Taiyshu"(太醫暑) was established. "Taiyshu"(太醫暑) taked complete charge of medical operation and education, published much excellent Obstetrics and Gynecology books than the past. Among them specially "Qianjinyaofang""千金要方" explained Obstetrics and Gynecology matter first in three volumes and "Qianjinyifang""千金翼方" explained this matter first in four volumes. This point indicate that Obstetrics and Gynecology's importance was established in Tang age, so Obstetrics and Gynecology's developmental history, Song age was the acme period. "Taiyju"(太醫局) was established in "xining""熙?" 9 year and Obstetrics belonged to one of nine departments under "Taiyun"(太醫局), so Obstetrics and Gynecology was separated from the other medical parts and it was prepared of it's progressing bases independently and appeared of changes in quality and increase in quantity about theory and prescription of Obstetrics and Gynecology, specially determination of treatment based on the differentiation of symptoms and sighs was taked a serious view. Besides four great physicians in Jing and Yuan dynasies diversified Obstetrics and Gynecology contents through their only medical theory and clinical treatment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.593-596
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• 2004

We are developing a micro-solid propellant rocket array thruster for simple attitude control of a 10 kg class micro-spacecraft. The prototype has ø 0.8 mm solid propellant micro-rockets arrayed at a pitch of 1.2 mm on a 22 x 22 mm substrate. In previous studies, an impulse thrust of 4.6 x 10$^{-4}$ Ns was obtained in vacuum, but we found the problems of unacceptably low ignition success rate and incomplete combustion. This paper describes experiments to improve the ignition rate. In order to achieve this goal, we tried to solidify paste-like ignition aid (RK) on the ignition heaters with strong adhesion. To make the paste-like RK, isoamyl acetate was added to RK powder. We tested 9 rockets, but only 2 rockets were ignited with huge ignition energy. This is because the heat con-duction between the ignition heater and the RK was too low to ignite the RK, since dried RK had a lot of pores. Also, a large cavity was sometimes found just above the ignition heater.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.734-743
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• 2017

In order to investigate the swelling behavior and fuel-cladding interaction mechanism of U-10Zr alloy metallic fuel at very low burnup, an irradiation experiment was concisely designed and conducted on the China Mianyang Research Reactor. Two types of irradiation samples were designed for studying free swelling without restraint and the fuel-cladding interaction mechanism. A new bonding material, namely, pure aluminum powder, was used to fill the gap between the fuel slug and sample shell for reducing thermal resistance and allowing the expansion of the fuel slug. In this paper, the concise irradiation rig design is introduced, and the neutronic and thermal-hydraulic analyses, which were carried out mainly using MCNP (Monte Carlo N-Particle) and FLUENT codes, are presented. Out-of-pile tests were conducted prior to irradiation to verify the manufacturing quality and hydraulic performance of the rig. Nondestructive postirradiation examinations using cold neutron radiography technology were conducted to check fuel cladding integrity and swelling behavior. The results of the preliminary examinations confirmed the safety and effectiveness of the design.

• Journal of the Korean Society of Food Culture
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• v.19 no.2
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• pp.223-238
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• 2004

In this paper, the differences between Korean and Japanese ways of seasonings are studied. The main results are summarized as follows: (1) Shouyu and Miso which are Japanese equivalents of soy sauce and bean paste of Korean foods are used in variety of different seasonings with some other ingredients while Korean counter parts are used only to add salty tastes. (2) Shouyu and Miso lose their flavors after considerable time of heating, while Korean soy sauce and bean pastes increase their tastes after heating. (3) Mirin adds sweety taste and glaze and Sake makes food soft or hard according to the moment of being added during cooking. (4) In Korean foods soy sauce, bean paste and red pepper paste are on the basis of tastes, Dashi is used in almost every Japanese food. (5) Seasoned vegetables of Korean food are prepared only with spices of green onion, garlic and sesame oil while seasoned fishes or vegetables are mixed with Shoyu or salt and vinegar in Japanese food. (6) In making Zorim, Korean traditional sauces are added from the beginning of heating. But in making Nimono, sugar, salt, vinegar, Shoyu and artificial taste are added in order during heating. (7) In grilling, main food for grilling in Korea is meat, which is prepared with a variety of spices such as soy sauce or/and red pepper pastes, garlic, green onion, sesame oil, sesame powder, pepper and sugar while mainly fishes are grilled with salt, occasionally with Shoyu or Miso in Japanese food. (8) Pan frying fishes are taken with soy sauce with vinegar in Korea but Tepura are eaten with Tentsuyu in Japan.