• Title/Summary/Keyword: 응고 속도

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Al-10wt%Ti-4wt%F Alloys as In-situ Composites through Rapid Solidification(II) (급냉응고법에 의한 In-Situ 복합재료로서의 Al-10wt%Ti-4wt%Fe 합금 (II))

  • Kim, Hye-Seong;Jeong, Jae-Pil;Gwon, Suk-In;Geum, Dong-Hwa
    • Korean Journal of Materials Research
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    • v.8 no.12
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    • pp.1127-1132
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    • 1998
  • The possibilities of producing Al-10%Ti-4%Fe composites through in-situ processing and thus achieving mechanical property improvements over binary Al-10%Ti to a level or higher exhibited by PM SiC/A12124 composites were explored in this study. The microstructure of in-situ processed Al-10%Ti-4%Fe composites was similar to that of Al matrix composites reinforced with discontinuous SiC particulates(SiC/A12124) and significant enhancements in elastic modulus, tensile strength and wear resistance were observed as compared to Al-10%Ti alloy. These results can be attributed to the in-situ formed Al. Fe by third element addition, leading to additional dispersion strengthening effect over $Al_3Ti$ phase reinforcement in Al-Ti system.

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Characteristics and Application of Defatted Soybean Meal fractions Obtained by Microparticulation/Air-Classification (초미세분쇄/공기분급을 이용한 탈지대두박 분획물의 특성과 응용)

  • Park, Dong-June;Ku, Kyung-Hyung;Kim, Seung-Ho
    • Korean Journal of Food Science and Technology
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    • v.28 no.3
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    • pp.497-505
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    • 1996
  • Defatted soybean meal (DSM) was microparticulated at cut-off whell speed of 9.000 rpm and air-classified into fine and coarse fractions at air classifying wheel speeds (ACWS) of 21,000, 18,000, 15,000 12,000 and 9,000 rpm stepwisely. Protein and ash content increased while lipid, carbohydrates and dietary fiber content decreased with decreasing ACWS. Amino acid composition and amino acid content of defatted soybean meal were similar to those of raw soybeans with aspartic and glutamic acid, the major amino acids. The yield and particle size increased with decreasing ACWS and mean particle size ranged from $4.9{\mu}m$ to $14.2{\mu}m$. The particles were oval-shaped with sharp corners. Water holding capacity, oil holding capacity and emulsion capacity slightly decreased with decreasing ACWS. Soybean curds formed showed different characteristics depending on the coagulant used and on the substitution ratio of full fat soybean flour with microparticulated DSM. Microparticulated DSM could successfully substitute wheat flour up to 10% level without bring no-ticiable beany flavor in the cakes.

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Microstructure and Mechanical Property of TiFe Compounds with Zr or Ce Prepared at Different Solidification Rates (TiFe금속간 화합물의 Zr과 Ce첨가와 냉각속도에 따른 응고 조직 변화 및 기계적 특성)

  • No, Hye-In;Choi, Chang-Wan;Yi, Seonghoon
    • Journal of Korea Foundry Society
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    • v.39 no.2
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    • pp.21-25
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    • 2019
  • Microstructural and corresponding hardness changes of TiFe compounds with Zr (0~6 at%) or Ce (0~3 at%) were studied using samples prepared at different solidification rates. In arc-melted (TiFe)-Zr samples, the $Fe_{23}$ $Zr_6$ and $(Ti,\;Zr)_2Fe$ phases formed in the TiFe matrix, while in the (TiFe)-Ce sample, the $CeO_2$ phase formed along the grain boundary of the TiFe matrix. As the Zr content was increased, the volume fractions of the $Fe_{23}$ $Zr_6$ and $(Ti,\;Zr)_2Fe$ phases increased, forming a network structure. Accordingly, the hardness values of the samples also increased. With a small addition of Ce of approximately 0.1 at%, the as-cast microstructure could be effectively refined, reducing the average grain boundary diameter from ${\sim}100{\mu}m$ to ${\sim}14{\mu}m$. In the rapidly solidified sample prepared through a melt-spinning method, the constituent phases were identical to those of the arc-melted samples while the grains were refined. The microstructural changes of TiFe alloys can affect the hydrogen storage ability as well as the mobility of the hydrogen atoms in the alloys.

Inhibitory Substance Produced by Aspergillus sp. on the Snake Venom Proteinase - Isolation of Microorganism and Biological Activities of the Inhibitor - (Aspergillus 속 균주가 생성되는 사독 Proteinase에 대한 저해물질 - 균의 분리 및 저해물질의 생물학적 작용상 -)

  • Hyun, Nam-Joo;Seu, Jung-Hwn
    • Microbiology and Biotechnology Letters
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    • v.15 no.2
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    • pp.129-134
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    • 1987
  • Aspergillus sp. (MK-24) producing a biological active substance that inhibited the venom proteinase activity was isolated from soil. The substance also inhibited the activity of trypsin and coagulation of blood, but did not inhibit papain, $\alpha$-chymotrypsin and pepsin. The substance was partially purified from culture filtrate by precipitaion with acetone, and by chromatography of DEAE-Sepadex A-50 column and Amberlite IRC-50 ion exchange. The inhibitory substance was stable in the wide pH range from 2.0 to 12.0 at 37$^{\circ}C$, but not stable at $65^{\circ}C$ in the alkaline pH. Only 12% of the activity was decreased by the heat treatment at 10$0^{\circ}C$ for two hours. The inhibition on venom proteinase (Agkistrodon bromohoffi brevicaudus) was a mixed type. The inhibitory activity depended on the preincubation time and completely depressed by cupric, zinc and cobalt ions. The inhibition on the venom proteinase was appeared strongly on casein but not on ovalbumin or hemoglobin as a substrate.

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Characteristics of Sn-Ag-Cu-In Solder Alloys Incorporating Low Ag Content (소량의 Ag를 함유하는 Sn-Ag-Cu-In계 솔더 재료의 특성 분석)

  • Yu, A-Mi;Lee, Jong-Hyun;Lee, Chang-Woo;Kim, Mok-Soon;Kim, Jeong-Han
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.18-18
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    • 2007
  • 지난 수년 동안 Sn-3.0Ag-0.5Cu 합금은 전자산업의 표준 무연솔더 조성으로 전자제품의 제작에 사용되어져 왔으며, 그 신뢰성도 충분히 검증되어 대표적인 무연 솔더 조성으로의 입지를 굳혀왔다. 그러나 전자제품의 mobile화에 따른 내충격 신뢰성에 대한 요구와 최근의 급격한 Ag 가격의 상승은 Ag 함량의 축소에 의한 원가절감을 요청하게 되었으며, 이에 따라 소량의 Ag를 함유하는 솔더 조성 개발에 대한 연구가 산업 현장을 중심으로 절실히 요청되고 있다. Sn-Ag-Cu의 3원계 함긍에서 Ag는 합금의 융점을 낮추고, 강도와 같은 합금의 기계적 특성을 증가시키는 한편, 모재에 대한 합금의 젖음성을 향상시키는데 필수적인 원소로 인식되고 있다. 따라서 Sn-Ag-Cu의 3원계 함금에서 Ag의 함량을 감소시키게 되면, 합금액 액상선 온도와 고상선 온도가 벌어져 pasty range(또는 mush zone)가 증가하게 되고, wettability도 감소하게 되어 솔더 합금으로서의 요구 특성을 많이 상실하게 된다. 또한 Ag 함량을 감소시키게 되면 합금의 elongation이 향상되면서 내 impact 수명이 향상되는 효과를 볼 수 있으나, 합금의 creep 특성 및 기계적인 강도는 감소하면서 열싸이클링 수명은 감소하는 경향을 나타내게 된다. 따라서 솔더 합금의 내 impact 수명과 열싸이클링 수명을 동시에 만족시키지 위해서는 Ag 함량을 최적화하기 위한 고려가 필요하며, 합금원소에 대한 연구가 요청된다고 하겠다. 한편 Ag의 함량을 3wt.% 이상으로 첨가할 경우에도 비교적 느린 응고 속도에서는 조대한 판상의 $Ag_3Sn$ 상을 형성하는 경향이 있어 외관 물량을 야기 시킬 가능성이 매우 커지는 현상도 보고되고 있다. 따라서 Ag의 첨가량을 최적화 하면서 솔더 재료로서의 특성을 계속적으로 유지하기 위해서는 제 4 원소의 함유가 필수적이라고 할 수 있다. 본 연구에서는 Sn-Ag-Cu계에 첨부하는 제 4원소로서 In을 선택하였다. 비록 In은 Ag보다 고가이기 때문에 산업적인 적용을 위한 솔더 합금 원소로는 거의 각광받지 못했으나, 본 연구의 결과로는 In은 매우 소량 첨가할 경우에도 Sn-Ag-Cu계 합금, 특히 소량의 Ag를 함유하는 Sn-Ag-Cu계 합금의 wettabilty와 기계적 특성 향상에 매우 효과적임을 알 수 있었다. 결론적으로 본 연구를 통해 구현된 Sn-Ag-Cu-In계 최적 솔더 조성의 경우 Sn-3.0Ag-0.5Cu의 표준 조성에 비하여 약 18%의 원자재 가격 절감을 도모할 수 있을 것으로 예상되는 한편. Sn-3.0Ag-0.5Cu에 유사하거나 우수한 wettability 특성을 나타내었고. Sn-1.0Ag-0.5Cu 또는 Sn-l.2Ag-0.5Cu-0.05Ni 조성보다는 월등히 우수한 wettability 특성을 나타내었다. 더구나 Sn-Ag-Cu-In계 최적 솔더 조성은 합금의 강도 저하는 최소화 시키면서 합금의 elongation은 극적으로 향상시켜 합금의 toughness 값이 매우 우수한 특성을 가짐을 알 수 있었다. 이렇게 우수한 toughness 값은 솔더 조인트의 대표적 신뢰성 요구 특성인 열싸이클링 수명과 내 impact 수명을 동시에 향상시킬 수 있을 것으로 예상된다. 요컨대 본 연구를 통해 구현된 Sn-Ag-Cu-In계 솔더 조성은 최적 솔더 조성에서 요구되는 4가지 인자, 즉, 저렴한 원재료 가격, 우수한 wettability 특성, 합금 자체의 높은 toughness, 안정하고 낮은 성장 속도의 계면 반응층 생성을 모두 만족시키는 특징을 가짐으로서 기존 무연솔더 조성의 새로운 대안으로 자리 잡을 것으로 기대된다.

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Temperature Dependent Creep Properties of Directionally Solidified Ni-based Superlloy CM247LC (일방향 응고 니켈기 초내열 합금 CM247LC의 온도에 따른 크리프 특성)

  • Choi, Baig-Gyu;Do, Jeonghyeon;Jung, Joong Eun;Seok, Woo-Young;Lee, Yu-Hwa;Kim, In Soo
    • Journal of Korea Foundry Society
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    • v.41 no.6
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    • pp.505-515
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    • 2021
  • Creep properties of directionally solidified Ni-based superalloy CM247LC under various temperature and stress conditions have been investigated. In the heat-treated specimen, some portion of eutectic γ-γ' remained, and uniform cubic γ' was observed in the dendrites. At low temperature (750℃) and high stress condition, a large amount of deformation occurred during the primary creep, while the tertiary creep region accounted for most of the creep deformation under high temperature and low stress condition. γ' particles are sheared by dislocation dissociated into super lattice partial dislocations separated by stacking faults at 750℃. No stacking faults in γ' were found at and above 850℃ due to the temperature dependence of the stacking fault energy. Raft structure of γ' was found after creep test at high temperature of 950℃ and 1000℃. At 850℃, the deformation mechanism was shown to be dependent on the stress condition, and so rafting was observed only under low stress condition.

Short Term Effects of Sodium Intakes on Serum Lipids and Glucose in Adult Women (단기간의 나트륨 섭취수준이 정상 성인 여성의 혈청 지질과 혈당에 미치는 영향)

  • 이영근;승정자;최미경;이윤신
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.6
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    • pp.1035-1042
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    • 2002
  • This study was conducted to investigate the effect of sodium intake on serum lipids and glucose. 20 young adult women were fed the diets containing 290.5 mEq (high-Na diet) and 51.3 mEq (low-Na diets) Na for 6 days, respectively. Serum lipids, glucose, and other parameters after high-Na diet and low-Na diet were compared. The results would be summarized as follows. The mean age, body weight, height, and blood pressure of the subjects were 22.9$\pm$2.5 years,54.7+6.6 kg, 160.0$\pm$4.8 cm, 110.3$\pm$7.7/67.5$\pm$19.7 mmHg, respectively. Body weight, BMI, and diastolic blood pressure were significantly higher at the end of high-Na diet than of low-Na diet (p<0.001 p<0.001, p<0.05). However, there were not significantly different in height and systolic blood pressure between high- and low-Na diet. Serum cholesterol, LDL-cholesterol, and HDL-cholesterol were not significantly different with Na intakes. Serum triglyceride was significantly higher at the end of high-Na diet than of low- Na diet (p<0.05) Serum apo A-I was significantly decreased in low-Na diet, while apo B was increased (p<0.001, p<0.001). Thrombin time and prothrombin time, blood aggregation time were significantly faster following low-Na diet (p<0.001, p<0.05). There was not significantly different in serum glucose between high- and low-Na diet. However, serum insulin was significantly higher following low-Na diet (p<0.01). It is concluded that diastolic blood pressure, serum triglyceride, serum apo A-I, blood aggregation time were decreased in low-Na diet, while serum apo B and serum insulin were increased. These results suggest that Na-restricted diet affects not only blood Pressure but other biochemical parameters in blood. Therefore, for the patients who need restricted Na diet, it would be suggested that various biochemical changes should be carefully considered along with dietary Na manipulation.

Clinical Implication of Images of Island : Based on Dreams, Sand Trays and Art Work of Four Korean Women (분석심리학적 관점에서 본 '섬' 상징의 임상적 적용 : 꿈, 모래상자, 그림작업에 출현한 섬 이미지 중심으로)

  • Jin-Sook Kim
    • Sim-seong Yeon-gu
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    • v.32 no.1
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    • pp.1-16
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    • 2017
  • The purpose of this paper is to illustrate the nature of Objective Psyche based on island related case materials. Theoretical background starts with psychological meaning of islands, a kind affective symbol rather than cognitive image, and creation myths as the story of man's awareness of the world; Chaos as archaic identity (unconscious), islands as emergence of the ego from unconscious. In alchemical symbolism, island related to coagulatio, the operation which turns something into earth, the realm of ego. In addition, related parts of Hindu creation myths, Korean giant woman creator Sulmoonde-halmang, and legends of "Relocation of Island/Mountain" will be presented to integrate with case materials. Case A : Starts with a dream of killing a huge dragon and dead body became an island. The dragon in the water was seen as Spirit of Mercurius, the autonomous spirit, connecting of the ego with the Self. The act of killing related to Primeval being which needs to be killed to be transformed. Myths of Eskimo, The Eagle's Gift, the giant woman creator in Korea, and Marduk, the Babylonian hero will be integrated. Case B : Prior to introduce six island images in sand trays, a dream of a giant serpent (python) wound around her body will be presented to portray her situation. By relating Jung's "The Sermons to the Dead," her effort to make the solid island regarded as an act of bringing order out of original oneness (pleroma). Then stresses the importance to coagulate archetypal image Case C : A vignette of active imagination seminar where island image emerged will be described. Her endeavor of focusing on inner image related to the Hindu Creator, Cherokee creation myth, as well as Sulmoonde-halmang. As a motif of growing island, Samoan creation myth, and Legend of Mountain, Mai were incorporated. Colors in her art work regarded as expression of inner need, and importance of expressing inner feeling images as a mean to coagulate volatile emotional and spiritual content. Case D : A dream and art work of terminally ill woman; embracing the tip of the island with gushing up water will be presented. Her island and replenishing water image regard as "an immortal body," corresponds to the Philosophers' Stone for she accepted her death peacefully after the dream. Also related to "The Mercurial Fountain" in Rosarium Philosophorum, and aqua permanence, an allegory of God.

Psychological Meaning of Creation Myths: Focused on Darkness/Massa Confusa, Separation of World Parent and Creation of Land/Island (무의식의 창조성 관점으로 고찰한 창조신화: 흑암/혼돈, 천지개벽/분리, 섬/육지 창조 중심)

  • Jin-Sook Kim
    • Sim-seong Yeon-gu
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    • v.38 no.2
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    • pp.269-304
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    • 2023
  • The purpose of this paper is to present the psychological meaning of the creation myths by utilizing related myths, analysand's dreams, active imagination, and artwork to reveal the creative function of the unconscious. The creation myth is the phenomenon of projection when a new order is demanded in the chaotic phase of personal and human history. Depending on the attitude of the ego, it can be a sign of a reconstruction/alteration of consciousness or an invasion. Related literature such as Jung, von Franz, Neumann, Harding, and Edinger, domestic papers, and case reports are introduced to identify the background for this research. The psychological meaning of 'darkness' in creation myths is regarded as unconscious that is too dark to see. The Eskimo creation myth and an analysand's dreams of being blind and wandering in darkness are discussed in relation to nigredo in Alchemy. The psychological meaning of 'massa confusa' regards Uroboros, pleroma, early childhood experience, and a psychological womb in which everything is contained in one. With related myths and unconscious materials, a discussion is followed on how this realm can be a precursor of creation but also be trapped in an abyss. The psychological meaning of 'separation of world parent' is related to splitting one into two when unconscious contexts were touched before it became consciousness. Related myths, 'the world created between heaven and earth,' 'celestial being descending to the earth,' and 'the legend of relocation of a mountain,' as well as clinical material, are examined. Then this paper discusses the clinical implications of the separation of heaven and earth occurring on its own, that the creator's emotional aspects, such as loneliness and anxiety, are involved, and that delayed separation leads to the death of creatura and sudden separation leads to the death of the chaos. Then, the meaning of 'separation of world parent' is discussed in relation with separatio, the alchemical process of acquiring light/consciousness from darkness/unconsciousness. The psychological meaning of the creation of 'land/island' refers to the emergence of consciousness, the contents of the unconscious material into the realm of the ego. Related myths, such as the 'body of the monster/dragon becoming land' and analysand's dreams, are introduced, referring to the embodiment of Mercurius. This is followed by discussing related myths in creating the land to coagulatio in alchemy and utilizing creative work such as active imagination, art, music, and dance that can coagulate or concretize unconscious material in clinical approaches. Finally, myths of resurfaced land after the Flood or the complete destruction of the world in relation to the reconstruction of ego are discussed with related clinical material to show the importance of the analyst/therapist/supervisor's mental stability and capacity.

The Effect of Pine (pinus densiflora) Needle Extracts on Blood Flow and Serum Lipid Improvement (적송잎 추출물의 혈행 및 지질개선 효과)

  • Kang, Sung-Rim;Kim, Young-Kyoung;Kim, Sung-Gu;Lee, Sang-Hyeon;Kim, Mi-Hyang
    • Journal of Life Science
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    • v.19 no.4
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    • pp.508-513
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    • 2009
  • Pine needles have long been used as a traditional health-promoting medicinal food in Korea. To investigate the effects of pine (pinus densiflora) needle extracts on blood flow and serum lipid improvement were assessed in vivo. 8 week-old Sprague Dawley strain rats were divided into four groups of seven rats each; CON, 0.5% CHOL, HOT water and Sub-supercritical group. Serum total cholesterol and triglyceride contents were lower in the CON group than the 0.5% CHOL group. Three weeks of feeding hot water and sub-supercritical extract resulted in a decrease in serum triglyceride and total cholesterol level. The level of HDL-cholesterol in the 0.5% CHOL group was significantly (p<0.05) reduced compared to the CON group, but it had a tendency to increase with pine needle extract supplementation. Blood passage time of the pine needle extracts supplemented group was higher than the 0.5% CHOL group. Microscopic observation showed that whole blood passed smoothly through the micro channels in pine needle extracts supplemented groups. The platelet aggregation ability of the groups treated with pine needle extracts was less than that of the 0.5% CHOL group. All these results suggest that pine needle extracts might improve blood homeostasis mediated via antiplatelet activities.