• 한국재료학회지
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• 제29권2호
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• pp.129-135
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• 2019

A powder mixture of 70 wt% $Al_2O_3$ and 30 wt% hydroxyapatite (HA) is sintered at $1300^{\circ}C$ or $1350^{\circ}C$ for 2 h at normal pressure. An $MgF_2$-added composition to make HA into fluorapatite (FA) is also prepared for comparison. The samples without $MgF_2$ show ${\alpha}$ & ${\beta}$-tricalcium phosphates (TCPs) and $Al_2O_3$ phases with no HA at either of the sintering temperatures. In the case of $1,350^{\circ}C$, a $CaAl_4O_7$ phase is also found. Densification values are 69 and 78 %, and strengths are 156 and 104 MPa for 1,300 and $1,350^{\circ}C$, respectively. Because the decomposition of HA produces a $H_2O$ vapor, fewer large pores of $5-6{\mu}m$ form at $1,300^{\circ}C$. The $MgF_2$-added samples show FA and $Al_2O_3$ phases with no TCP. Densification values are 79 and 87 %, and strengths are 104 and 143 MPa for 1,300 and $1,350^{\circ}C$, respectively. No large pores are observed, and the grain size of FA ($1-2{\mu}m$) is bigger than that of TCP ($0.7{\mu}m{\geq}$) in the samples without $MgF_2$. The resulting $TCP/Al_2O_3$ and $FA/Al_2O_3$ composites fabricated in situ exhibit strengths 6-10 times higher than monolithic TCP and HA.

• 대한음성학회지:말소리
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• 제63호
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• pp.47-66
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• 2007

This study aims at exploring the degree of phonetic similarity between Korean and Japanese vowels in terms of acoustic features by performing the speech production test on Korean speakers and Japanese speakers. For this purpose, the speech of 16 Japanese speakers for Japanese speech data, and the speech of 16 Korean speakers for Korean speech data were utilized. The findings in assessing the degree of the similarity of the 7 nearest equivalents of the Korean and Japanese vowels are as follows: First, Korean /i/ and /e/ turned out to display no significant differences in terms of F1 and F2 with their counterparts, Japanese /i/ and /e/, and the distribution of F1 and F2 of Korean /i/ and /e/ in the distributional map completely overlapped with Japanese /i/ and /e/. Accordingly, Korean /i/ and /e/ were believed to be "identical." Second, Korean /a/, /o/, and /i/ displayed a significant difference in either F1 or F2, but showed a great similarity in distribution of F1 and F2 with Japanese /a/, /o/, and /m/ respectively. Korean /a/ /o/, and /i/, therefore, were categorized as very similar to Japanese vowels. Third, Korean /u/, which has the counterpart /m/ in Japanese, showed a significant difference in both F1 and F2, and only half of the distribution overlapped. Thus, Korean /u/ was analyzed as being a moderately similar vowel to Japanese vowels. Fourth, Korean /${\wedge}$/ did not have a close counterpart in Japanese, and was classified as "the least similar vowel."

• 한국전기전자재료학회논문지
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• 제11권3호
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• pp.242-247
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• 1998

In this study, we have synthesized $ZnGa_2O_4$:Mn,X powder doped with Mn, MnO, $MnF_2$ and $MnCl_2$, low voltage green emitting phosphor, in vacuum atmosphere. From PL spectra, the intensity of the emission peak, the brightness with coactivator show that $ZnGa_2O_4$:Mn,Cl > $ZnGa_2O_4$:Mn,F > $ZnGa_2O_4$:Mn,O > $ZnGa_2O_4$:Mn. These improvement of the brightness are caused by the increase of the concentration of $Mn^{2+}$ ion. In case of $ZnGa_2O_4$:Mn,Cl and ZnGa$_2$O$_4$:Mn,F, the brightness is enhanced much more, which is owed to the decrease of defect of host material. For $ZnGa_2O_4$:Mn,Cl phosphor fabricated with optimized condition, the decay time becomes short from 30 ms of the $ZnGa_2O_4$:Mn and $ZnGa_2O_4$:Mn,O to 6 ms and the brightness of CL at 1 kV, 1 mA is 60 cd/$m^2$.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.307-312
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• 1994

The authors have been devoted to researches on fuzzy theories and their applications, especially control theory and application problems, for recent years. In this paper, the authors present results on a comparison of optimal solutions between ones of an ordinary-typed mathematical linear programming problem(O.M.I.P. problem) and ones of a Zimmerman-typed fuzzy mathematical linear programming problem (F.M.L.P. problem), and comment about the sensitivity (differences and fuzziness on between O.M.L.P. problem and F.M.L.P. problem) on optimal solutions of these mathematical linear programming problems.

• 한국산학기술학회논문지
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• 제16권8호
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• pp.5485-5491
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• 2015

본 연구의 목적은 MBTI의 인식기능(S/N)과 판단기능(T/F)에 대한 문양역전 시각유발전위(PR-VEP)의 특성을 알아보고자 하는 것이다. 연구 대상자는 20세 이상의 성인남녀 136명을 대상으로 2013년 7월부터 8월까지 2개월 동안 PR-VEP와 MBTI검사를 실시하였다. PR-VEP검사는 32채널 뇌파측정기를 이용하여 O1, O2에서 측정하였고, MBTI검사는 Form-M 온라인검사방법을 이용하였다. 연구결과는 S지표 선호집단에서 PR-VEP의 N75와 P100 사이의 시간간격(Duration)이 5.49 ms 유의미하게 짧았고, F지표 선호집단에서 PR-VEP의 N75가 나타나기까지의 잠복기(Latency)가 O1에서 4.83 ms, O2에서 4.27 ms 유의미하게 짧았다. 이는 S유형과 F유형의 특징이 시각적 인지기능과 관계가 있다는 것을 의미하는 것으로, MBTI의 인식기능/판단기능 각 지표에 대한 뇌과학적 해석을 더할 수 있다는 점이 본 연구가 갖는 의의이다.

• Korean Chemical Engineering Research
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• 제47권1호
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• pp.11-16
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• 2009

단일벽 탄소나노튜브의 표면 위에 동력학적 전위법으로 산화루테늄($RuO_2$)의 석출 및 루테늄-코발트 혼합산화물(Ru-Co mixed oxide)의 공석출에 의해 산화환원 수퍼커페시터용 복합전극을 제조하였다. 루테늄 성분이 13.13 wt%, 코발트 성분이 2.89 wt%가 석출된 Ru-Co 혼합산화물 전극은 낮은 전위 스캔속도($10\;mV\;s^{-1}$)에서는 $RuO_2$ 전극과 유사한 비용량(${\sim}620\;F\;g^{-1}$)을 나타내지만, 높은 스캔속도($500\;mV\;s^{-1}$)에서는 $RuO_2$ 전극보다 큰 비용량을 보인다. 높은 스캔 속도에서 Ru-Co 혼합산화물 전극이 비용량의 증가를 나타내는 것은 Ru 성분을 통한 전기전도성을 Co 성분이 구조적으로 지지해주기 때문이다.

• 한국세라믹학회지
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• 제43권5호
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• pp.320-326
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• 2006

Mullite whiskers were synthesized by a vapor-solid reaction with $Al(OH)_3-SiO_2-AlF_3$. The heat treatment temperature did not affect the shape of mullite whisker but the composition change resulted in different sizes. The first one was $30-50{\mu}m$ in size with the aspect ratio of 60 and above, and the second one was $600{\mu}m$ and below in size with the aspect ratio of 15 and below. The $Al_2O_3$ content in formed mullite whisker was 73.57-80.29 wt%, which is high $Al_2O_3$ content composition. The Young's modulus and the hardness measured by nano-indentation method were 136.7 GPa and 19.81 GPa, respectively.

• 한국자기학회지
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• 제5권1호
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• pp.64-70
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• 1995

$ThMn_{12}$ 구조를 갖는 $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$의 결정학적 및 자기적 성질을 X선 회절법과 VSM, $M\"{o}ssbauer$분광법으로 연구하였다. $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$합금은 알곤가스 분위기의 아크 용해로에서 제조하였다. $NdFe_{10.7}TiM_{0.3}$의 결정구조는 순수 단일상의 tetragonal구조를 갖고 있으며 $a_{0}=8.587\;{\AA},\;c_{0}=4.788\;{\AA}$의 격자상수를 결정하였다. $M\"{o}ssbauer$ spectrum은 13 K 부터 770 K 영역까지 취하였으며 Curie 온도는 $NdFe_{10.7}TiM_{0.3}$의 경우 $570{\pm}3\;K$로 결정하였다. $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$은 $8i_{1},\;8i_{2},\;8j_{1},\;8j_{2}$ 및 8f의 5 set의 Fe 이온의 subspectra로 분석하였다. $NdFe_{10.7}TiM_{0.3}$의 실온에서 Fe-site $8i_{1},\;8i_{2},\;8j_{1},\;8j_{2}$ 및 8f는 16.4, 8.2, 14.8, 21.3 및 39.3%의 면적비를 각각 가지고 있었다. 초미세자기장은 $H_{hf}(8i)>H_{hf}(8j)>H_{hf}(8f)$비로 감소함을 알았다.

• Biomolecules & Therapeutics
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• 제6권2호
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• pp.111-118
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• 1998

Ambroxol is thought to have antioxidant ability and some antiinflammatory effect. Effect of ambroxol on the oxidative damages of lipid, collagen and hyaluronic acid was examined. F $e_{2+}$(10 $\mu$M) and 100$\mu$Mascorbate-induced lipid peroxidation of liver microsomes was inhibited by 10 and 100$\mu$M ambroxol, 30$\mu$g/ml catalase and 10 mM DABCO but was not affected by 30$\mu$g/ml SOD and 10 mM DMSO. A 10 and 100$\mu$M ambroxol and 10 mM DABCO inhibited the peroxidative action of 10$\mu$M F $e_{3+}$, 160$\mu$M ADP and 100$\mu$M NADPH on microsomal lipids, whereas inhibitory effects of 30$\mu$g/ml SOD,30$\mu$g/ml catalase and 10 mM DMSO were not detected. The degradation of hyaluronic acid caused by 107M Fe2\\`,5007M H2O2 and 100$\mu$M ascorbate was inhibited by 10 and 100$\mu$M ambroxol,30$\mu$g/ml catalase,10 mM DMSO and 10 mM DABCO, while 30$\mu$g/ml SOD did not show any effect. The cartilage collagen degradation caused by 307$\mu$ F $e_{2+}$,500$\mu$M $H_2O$$_2$ and 200$\mu$M ascorbate was prevented by 100$\mu$M ambroxol. $H_2O$$_2$ and OH . were scavenged by ambroxol, whereas $O_2$, was not removed by it. Ambroxol (100$\mu$M) and 1 mM cysteine reduced DPPH to 1,1-diphenyl-2-picrylhydrazine. In conclusion, ambroxol may inhibit the oxidative damages of lipid, hyaluronic acid and collagen by its scavenging action on oxidants, such as OH . and probably iron-oxygen complexes and exert antioxidant ability.

• 한국독어학회지:독어학
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• 제5집
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• pp.375-398
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• 2002

Um von der 'kritischen' Situation des Faches DaF rauszukommen, werden viele Versuche untemommen, durch die Verbesserung des Untenichts in der Richtung nach der Entwicklung der kommunikativen $F\"{a}higkeit$ Deutsch als Fremdsprache wieder attraktiv und $konkurrenzf\"{a}hig$ zu machen. Aber leider sieht die Zwischenbilanz nicht so erfolgreich aus. Eine der Ursachen $daf\"{u}r\;l\"{a}sst$ sich mE. darin sehen, dass die $Ans\"{a}tze,\;die\;haupts\"{a}chlich\;f\"{u}r$ den Unterricht von Deutsch als Zweitsprache entwickelt wurden, ohne $gen\"{u}gende$ Berucksichtigung auf die kulturellen und institutionellen Unterschiede zwischen den Lemsituationen im zielsprachigen Land und im Heimatland der Schuler eingesetzt werden. In diesem Kontext $w\"{a}re\;es\;n\"{o}tig$, auf die Unterschiede zwischen DaF und DaZ und ihre Wirkung auf die Lehrstrategien im DaF-Unterricht zuruckzugreifen, Dabei sind auf einige Faktoren besonders zu achten, die DaF-Untenicht vom DaZ-Untenicht unterscheiden: die Mangel an den $M\"{o}glichkeiten$ der authentischen Kommunikation, die $Homogenit\"{a}t\;der\;Sch\"{u}ler$, die Lemkultur in der schlulischen Institution, das Alter, in dem die Sch\"{u}ler$ mit dem Lemen der Zielsprache beginnen. Daraus lassen sich die folgenden unterrichtlichen Konsequenzen ergeben: Die Lehrer sollten sich bemtihen, den $Sch\"{u}lern\;die\;M\"{o}glichkeiten\;f\"{u}r$ die authentischen Kommunikation besorgen, besonders $au{\ss}erhaib$ des Unterrichts, z.B. durch das Chatting- Projekt, $w\"{a}hrend$ im Unterricht mehr $Anl\"{a}sse\;f\"{u}r$ die Reflexion gegeben sollten. Und dabei sollten die unterrichtlichen Vorteile-die gemeinsame Muttersprache und Kultur, das Alter usw. - aktiv benutzt werden. Die meisten Koreaner beginnen $n\"{a}mlich$ mit dem Lernen der zweiten Fremdsprache erst in oder nach der $Pubert\"{a}t$. In diesem Zusammenhang sollte es auch betont werden, dass sich die Autonomie der Lerner durch den Unterricht richtig entwickelt, damit sie $sp\"{a}ter$ ihre Fertigkeiten autonom entwickeln $k\"{o}nnen$.