• Journal of Welding and Joining
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• v.20 no.6
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• pp.809-815
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• 2002

Metallurgical behavior of laser welded cold rolled low carbon steel was investigated. Welding was performed with CW Nd:YAG laser system. Applied laser power, travel speed and nitrogen blowing pressure were 720W CW, 17mm/s and 196kPa, respectively. According to the test results, many carbide particles were observed on the base metal surface that was polished and etched with nital solution. The carbide particles at the welding heat affected zone were thought to be dissolved during welding process. Microstructural inspection revealed that dissolved carbide particles formed mixed phase of very fine martensite and bainite. Test results also demonstrated that the hardness of matrix remained constant value of around 160Hv over the welding heat affected zone. Dissolved carbide particles, however, showed higher average hardness values of around 276Hv near the fusion boundary and 700Hv at the welding heat affected zone of 0.4mm apart from the fusion line. It was considered that care should be given to minimize the test error when measuring the hardness value since many of the dissolved particles were so small that it was not easy to aim the indentor of the testing machine just on the objects.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.889-892
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• 2004

The synthesis of $Zn_{2}SiO_4:Mn^{2+}$ for PDP green phosphor by SHS(Self-propagating High temperature Synthesis method) was studied. The precursors were well mixed and cold compacted. And then, the green pellet was synthesized at high temperature through self-propagating high temperature zone. Because this reaction uses the heat resulted from the oxidation of Zn metal powder in this system, Zn/ZnO mole ratio is one of the most important reaction variable. Throughout several experiments, the optimal condition of Zn/ZnO mole ratio and Mn concentration are 1.2/0.8 and 0.05mo1e, respectively.

• Korean Journal of Head & Neck Oncology
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• v.17 no.1
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• pp.52-55
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• 2001

We present a case of a mixed papillary and follicular thyroid cancer in a 45-year-old female presented with palpable mass on anterior neck area for 1 week ago. Neck CT and ultrasonogram revealed small solid masses in the both lobes of the thyroid gland. Thyroid scintigraphy presents as a cold nodule in the right lobe of the thyroid gland and FNA cytology demonstrated papillary thyroid cancer. At the time of operation, small sized solid masses were detected in the both lobes, and no cervical lymph nodes enlargement along the mass. Biopsies of the both mass demonstrated papillary cancer on right lobe and follicular cancer on left lobe. Simultaneous papillary and follicular thyroid cancer is an extremely rare clinical entity. We experienced a case of simultaneous papillary and follicular thyroid cancer, so we report it with a review of some articles.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.26-33
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• 2014

The gas-centerd swirl injectors are widely used on the main combustor of large liquid propellant rocket engines. Since the gas-liquid propellants, such as kerosene and oxygen-rich gas combination, are mixed and burned in the high pressure condition over the critical pressure point, the cold-flow spray test in the atmospheric condition can not represent the actual spray pattern. To observe the near actual spray patterns of gas-centered swirl injector, the high pressure spray chamber and the control system were constructed. The operating sequence was controlled precisely to obtain clear visualization images.

• Journal of Powder Materials
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• v.14 no.3 s.62
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• pp.202-207
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• 2007

Novel polymer mold process for fabrication of microcomponents using metal nanopowders was developed and experimentally optimized. Polymer mold for forming green components was produced by using a hard master mold and polydimethylsiloxane (PDMS). In the preparation of metallic powder premix for the green components without any defect, 90 wt.% 17-4PH statinless steel nanopowders and 10 wt.% organic binder were mixed by a ball milling process. The green components with very clear gear shape were formed by filling the powder premix into the PDMS soft mold in surrounding at about $100^{\circ}C$. Cold isostatic pressing (CIP) was very potent process to decrease a porosity in the sintered microcomponent. The microgear fabricated by the improved process showed a good dimension tolerance of about 1.2%.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.5
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• pp.785-793
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• 2010

This study aimed to identify particular foods that would be most appropriate as representatives foods of Daejeon, as well as the key factors affecting the branding of image of those foods. To achieve these aims we carried out a survey amongst 1,600 citizens and visitors. The Daejeon representative foods were determined to be Gujeuk Dotorimuk (Gu-jeuk acorn jelly), Hanbat Seolleongtang, Dolsotbap (stone pot mixed rice), Sutgol naengmyeon (Sutgol Cold Noodles), Daecheongho Minmulmaeuntang (Daecheong lake freshwater spicy fish soup) and Samgyetang (casserole of spatchcock with ginseng). These six dishes were designated as representative foods in 2001. Findings from the survey indicated the lowest level of brand! dish awareness was 11.6% generally and the top two preferences for the representative foods were ranked as, Samgyetang (24.8%) and Dolsotbap (23.6%). According to an awareness survey age differences played a significant role. Adults displayed a much higher awareness than younger generations. The survey also found that Daejeon city was strongly associated with images of science and technology, particularly areas such as Expo and the Daedeok Valley. This study's results suggests that developing a menu and marketing strategy based upon associated regional images may increase awareness for local foods among young consumers.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.71-75
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• 1990

Yoghurt was prepared with Bifidobacterium longum TK-100 and Lactobacillus acidophilus TK-2070. The prepared yoghurt showed the increase of the titratable acidity under cold storage condition. This was derived from the active L. acidophilus TK-2070 on the logarithmic phase rather than from the B. longumn TK-2070. B. longum TK-100 grew well in the facultative anaerobic condition as well as in the strict anaerobic condition. Reinforced clostridial agar medium with 0.1% aniline blue was tried for the differential viable cell counts in the mixed culture and in the yoghurt. B. longurn TK-2070 had the light gray, blue-dotted colonies of about 2 mm diameter. L. acidophilus TK-2070 had the light gray colonies of about 1 mm diameter.

• Tribology and Lubricants
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• v.11 no.4
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• pp.28-34
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• 1995

PTFE has good mechanical and chemical stability at wide temperature range, and more over, shows a low value of friction coefficient. On the other hand, it shows cold flow and high wear rate. However, these short comings can be overcome by adding various fillers. In this experiment, PTFE and polyimide powder were mixed into composite and its tribological characteristics was investigated. 100% polyimide was also tested for comparison. The countefface material was a stainless steel (SUS304). Friction and wear tester of ring-on-block type was used at room temperature and under atmosphere. After the wear test, the worn surfaces were examined by optical microscope. The test results show that PTFE-polyimide composite generates. the wear transfer film on both sides of the friction surfaces, and, the friction coefficient and the wear rates are relatively low. 100% polyimide generated little wear transfer films, showed high friction and wear rates, and also showed some problems of vibration and noise. It even damaged the stainless steel countefface. It was concluded that 100% polyimide does not generate transfer film well because its shear resistanbe is high and it stickslips, thus, friction coefficients and wear rates are high. In case of PTFE-polyimide composite, on the other hand, transfer film containing sufficient PTFE adheres and remains on both wear surfaces well enough because PTFE has low shear resistance. Polyimide particles in the composite were proved to be able to bear normal load and does not show stick-slip because they are covered with transfer film containing much PTFE.

• Korean Journal of Materials Research
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• v.15 no.7
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• pp.473-479
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• 2005

Thermoelectric $Zn_4Sb_3$ alloys were synthesized by a conventional powder metallurgy process consisting of solid state reaction and hot pressing. Single phase $Zn_4Sb_3$ was successfully produced by the annealing of cold compact starting with the mixed elemental powders, and subsequent hot pressing yielded single phase bulk specimens without microcracks. Phase transformations in this alloy system during synthesis were investigated using XRD, SEM and EDS. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of analogue studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by this process are comparable to the published data. Synthesis by solid state reaction and hot pressing offers a potential processing route to produce a bulk $Zn_4Sb_3$.ٓ

• Journal of the Korean Society of Food Culture
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• v.11 no.1
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• pp.7-12
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• 1996

The 18th Winter Universiade will be held in Muju in 1997. It is a good opportunity to inform the local foods of Muju to the inside and outside of Korea. First of all, we carefully investigated the quantity of all kinds of food material, their circulation ability, and cookery per year in Muju. We found about sixty kinds of food as many as restaurant. We presented how to improve such kinds of food as O-Chunk (fish porridge), Minmulmaeuntang, Kochunaengi chungsik, etc. and how to use the special products of Muju such as yam, kochunaengi, wasabi and wild herb. The many kinds of cookery were specialized to cooks through manual and actual skills. And then we held a food contest that twenty-two cooks took part in the contest and there were exhibitted forty-two kinds of foods. Finally, through discussion and food contest, Muju Sanchae Bibimbap (meal which mixed rice with wild plants), Muju Sanchae chungsik (meal which has various wild plants with rice), Muju Kochunaengi Chungsik (meal which has various wild plants and wasabi with rice), Ma Naengmyun (cold yam noodle) and Muju Minmulmaeuntang (hot fish porridge) were recommended.