• 자원환경지질
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• 제8권3호
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• pp.117-124
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• 1975

경북(慶北) 봉화군(奉化郡) 소재(所在) 장군광산(將軍鑛山)의 표성산화(表成酸化)망간광석중(鑛石中)에서 필자(筆者)에 의(依)하여 발견명명(發見命名)된 신종건물(新種鍵物) 장군석(將軍石)은 국제(國際) 광물학회내연합(鑛物學會內聯合)에 있는 "신종광물(新種鑛物) 및 광물명위원회(鑛物名委員會)"의 공인(公認)을 받았는바 이에 대(對)한 광물학적(鑛物學的)인 연구결과(硏究結果)를 요약(要約)하면 다음과 같다. (1) 장군석(將軍石)은 표성산화(表成酸化)망간 광석중(鑛石中) cementation zone에서 산출(産出)되며, 엔소타이트, 토도로카이트, 방해석(方解石)을 수반(隨伴)한다. 대체로 공동(空洞)에서 수기상(樹技狀) 또는 방사상(放射狀)을 이루는 엽편상(葉片狀) 세립집합체(細粒集合體)(입자(粒子)의 크기 <0.05mm)로 또는 교질상대(膠質狀帶)로 산출(産出)한다. (2) 색(色)은 흑색(黑色)이며 광택(光澤)은 무염(無艶), 조흔(條痕)은 흑갈(黑褐)~암갈(暗褐色)이다. 벽개(劈開)는 한방향(方向)으로 완전(完全)하다. 경도(硬度)(H)=2-3이며 역쇄성(易碎性)이다. 비중(比重)(G)=3.59(실측시(實測植)), 3.58이론치(理論値)이다. (5) 화학분석치(化學分析値)로부터 계산(計算)된 장군석(將軍石)의 화학식(化學式)은 $Mn^{4+}{_{4.85}}(Mn^{2+}{_{0.90}}Fe^{3+}{_{0.30}})_{1.20}O_{8.09}(OH)_{5.91}$이며, 이상식(理想式)은 $Mn^{4+}{_{5-x}}(Mn^{2+},\;Fe^{3+}){_{1+x}}O_8(OH)_6$ ($x{\approx}0.2$)이다. (6) 장군석(將軍石)은 사방정사 속(屬)하며 X선(線) 분말회절분석(粉末廻折分析) 결과(結果), 단위포(單位胞)의 크기는 $a=9.324{\AA}$, $b=14.05{\AA}$, $c=7.956{\AA}$이며, 단위포(單位胞)의 체적(體積)은 $1042.25{\times}10^{-24}cm$이다. 보솔(輔率) a : b : c=0.663 : 1 : 0.566. 단위포함유수(單位胞含有數) (Z)=4. (7) 시차열분석곡선(示差熱分析曲線)은 $250{\sim}370^{\circ}C$와 $955^{\circ}C$에서 흡열(吸熱)피크를 보여준다. 전자(前者)는 장군석(將軍石)이 탈수(脫水) 및 산화(酸化)를 받아 $(Mn,\;Fe)_2O_3$이 생성(生成)된데 기인(基因)하며 후자(後者)는 hausmannite 형(型)의 구조(構造)를 갖는 $(Mn,\;Fe)_3O_4$의 생성(生成)에 기인(基因)하는 것이다. $(Mn,\;Fe)_2O_3$는 등보정사이고 $a=9.417{\AA}$이었고 $(Mn,\;Fe)_3O_4$는 정방정사이고 $a=5.76{\AA}$, $c=9.51{\AA}$이었다. (6) 장군석(將軍石)의 적외선흡수분광(赤外線吸收分光)스펙트럼은 $515cm^{-1}$와 $545cm^{-1}$에서 Mn-O stretching 진동(振動)을, $1025cm^{-1}$에서 O-H bending 진동(振動)을 그리고 $3225cm^{-1}$에서 O-H stretching 진동(振動)을 보여준다. (3) 장군석(將軍石)은 불투명광물(不透明鑛物)이며 현미경하(顯微鏡下)에서 반사도(反射度)는 13~15%이고 복반사율(複反射率)은 공기중(空氣中)에서 현저(顯著)하며 침액중(浸液中)에서 강(强)하다. 반사다색성(反射多色性)은 백색(白色)~담회색(淡灰色)이다. 십자(十字)니콜하(下)에서의 편광색(偏光色)은 공기중(空氣中)에서 청색(靑色)을 띈 황갈(黃褐)~회색(灰色)이고 침액중(浸液中)에서는 黃褐(황갈)~청갈(靑褐)~회색(灰色)이다. 내부반사(內部反射)는 없다. (4) 연마면(硏磨面)에 대(對)한 에칭반응(反應)은 HCl(conc.)와 $H_2SO_4+H_2O_2$ 회색(灰色), 퇴색(褪色), SnCl(sat.): 암색(暗色), $HNO_3$ (conc.) : 회색(灰色), $H_2O_2$ : 거품을 내며 퇴색(褪色). (9) 신종광물(新種鑛物) 장군석(將軍石)은 독특(獨特)한 화학조성(化學組成)과 단위포(單位胞)를 가지고 있어서 이의 발견(發見)은 산화(酸化)망간광물(鑛物)의 분류(分類)와 연구(硏究)에 새로운 방향(方向)과 지침(指針)이 되었다.

• 한국물환경학회지
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• 제30권3호
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• pp.261-268
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• 2014

Four clays (both natural and commercial types) mainly used in Korea were tested for removal efficiency of Microcystis spp. and ecotoxicity on Daphnia magna and Vibrio fischeri. Four clays (clay A~D) were composed of 91.9~100% of sand (0.02~0.2 mm in particle size). Clay D consisted of lager particles than other clays. Major elements of the four clays were $SiO_2$ (45.3~62.8%), $Al_2O_3$ (18.5~29.7%) and $Fe_2O_3$ (5.4~7.9%). They contained kaolinite (clay mineral), quartz, muscovite, and so on. Clay C and D contained montmorillonite, one of the clay minerals improving clay-cell aggregation. For clay A, B and C, removal efficiency of Microcystis spp. was over 60% at 2 g/L. It reached about 100% at over 5 g/L. For clay D, it was over 60% and 95~100% at 5 g/L and 20 g/L respectively. After adding clays, pH decreased. The greatest drop of pH appeared at clay C. Except for addition of 100 g/L clay C, ecotoxicity on D. magna and V. fischeri didn't appeared at all dose of clays.

• 대한수학회지
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• 제46권1호
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• pp.187-213
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• 2009

For a positive integer k and an arbitrary integer h, the classical Dedekind sums s(h,k) is defined by $$S(h,\;k)=\sum\limits_{j=1}^k\(\(\frac{j}{k}\)\)\(\(\frac{hj}{k}\)\),$$ where $$((x))=\{{x-[x]-\frac{1}{2},\;if\;x\;is\;not\;an\;integer; \atop \;0,\;\;\;\;\;\;\;\;\;\;if\;x\;is\;an\;integer.}\$$ J. B. Conrey et al proved that $$\sum\limits_{{h=1}\atop {(h,k)=1}}^k\;s^{2m}(h,\;k)=fm(k)\;\(\frac{k}{12}\)^{2m}+O\(\(k^{\frac{9}{5}}+k^{{2m-1}+\frac{1}{m+1}}\)\;\log^3k\).$$ For $m\;{\geq}\;2$, C. Jia reduced the error terms to $O(k^{2m-1})$. While for m = 1, W. Zhang showed $$\sum\limits_{{h=1}\atop {(h,k)=1}}^k\;s^2(h,\;k)=\frac{5}{144}k{\phi}(k)\prod_{p^{\alpha}{\parallel}k}\[\frac{\(1+\frac{1}{p}\)^2-\frac{1}{p^{3\alpha+1}}}{1+\frac{1}{p}+\frac{1}{p^2}}\]\;+\;O\(k\;{\exp}\;\(\frac{4{\log}k}{\log\log{k}}\)\).$$. In this paper we give some formulae on the mean value of the Dedekind sums and and Hardy sums, and generalize the above results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1349-1352
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• 2005

This paper is to investigate a defect for thermal barrier coating layers by acoustic emission method in 4-point bending test. The two-layer thermal barrier coating is composed of $150\mu{m}\;CoNiCrAlY\;bond\;coating\;by\;vacuum\;plasma\;spray(VPS)\;process\;and\;250\mu{m}\;ZrO_2-8wt%Y_2O_3$ ceramic coating layer by air plasma spray(APS) process on Inconel-718. The specimen prepared by cyclic thermal test(500, 1000, 2000cycle) at $1050^{\circ}C$ The AE monitoring system is composed of PICO type sensor, a wide band pre-amplifier(40dB), PC and AE DSP(16/32 PAC) board. The AE event, amplitude, Cumulative energy and count of coating specimens is evaluated according to cyclic thermal test.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.169.2-169.2
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• 2015

$VO_2$ is a well-known a metal-to-insulator-transition (MIT) material, accompanied with a first order structural phase transition near room temperature. Because of the structural phase transition and the MIT occur near a same temperature, there is an ongoing argument whether the MIT is induced by the structural phase transition. $VO_2$ exhibits a relatively weak anti-oxidization ability and can be oxidized to higher-valence oxides (e.g., $V_4$ $O_7$ or $V_2$ $O_5$) when annealed at a high temperature in an oxygen-rich atmosphere. We fabricated $VO_2$ films on $Al_2$ $O_3$ (0001) substrates using a DC magnetron sputtering deposition process with carefully control the $O_2$ percentage in an atmosphere. X-ray diffraction measurements from the films showed only (0l0) peaks with no extra peaks, indicating b-oriented films. The temperature-dependent local structural properties of $VO_2$ films were investigated by using in-situ X-ray absorption fine structure (XAFS) measurements at the V K edge. XAFS revealed that the structural phase transition was occurred nearly $70^{\circ}C$ for heating process and reproducible. Resistance measurements as a function of temperature (R-T) demonstrated that the resistance of $VO_2$ films was changed by a factor of 4 near $75^{\circ}C$ which was higher than $68^{\circ}C$ reported from a $VO_2$ bulk. We will discuss the MIT of $VO_2$ films, comparing with the local structural properties determined by XAFS measurements.

• 대한조선학회지
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• 제22권1호
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• pp.45-53
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• 1985

For the analysis of vertical vibrations of a ship's hull, the Timoshenko beam analogy is accepted up to seven or eight-node modes provided that the system parameters are properly calculated. As to the shear coefficient, it has been a common practice to apply the strain energy method or the projected area method. The theoretical objection to the former is that it ignores lateral contraction due to Poisson's ratio, and the latter is of extreme simplifications. Recently, Cowper's and Stephen's shear coefficient formulas have drawn ship vibration analysts' attentions because these formulas, derivation of which are based on an integrations of the equations of three-dimensional elasticity, take Poisson's ratio into account. Providing computer programs for calculation of the shear coefficient of ship sections modeled as thin-walked multicell sections by each of the forementioned methods, the authors calculated natural vibration characteristics of a bulk carrier and of a container ship by the transfer matrix method using shear coefficients obtained by each of the methods, and discussed the results in comparision. The major conclusions resulted from this investigation are as follows: (1) The shear coefficients taking account of the effects of Poisson's ratio, Cowper's $K_c$ and Stephen's $K_s$, result in higher values of about 10% in maximum as compared with the shear coefficient $K_o$ based on the conventional strain energy methods; (a) $K_c/K_o{\cong}1.05\;and\;K_s/K_o{\cong}1.10$ for ships having single skin side-shell such as a bulk carrier. (b) $K_c/K_o{\cong}1.02\;and\;K_s/K_o{\cong}1.05$ for ships having longitudinally through bulkheads and/or double side-shells in the portion of the cargo hod such as a container carrier. (2) The distributions of the effective shear area along the ship's hull based on each of $K_o,\;K_c\;and\;K_s$ are similar each another except the both end portions. (3) Natural frequencies and mode shapes of the hull based on each of $K_c\;and\;K_s$ are of small differences as compared each other. (4) In cases of using $K_c\;or\;K_s$ in ship vibration analysis, it is also desirable to have the bending rigidity be corrected according to the effective breadth concept. And then, natural frequencies and mode shapes calculated with the bending rigidity corrected in the above and with each of $K_o,\;K_c\;and\;K_s$ result in small differences as compared each another. (5) Referring to those mentioned in the above (3) and (4) and to the full-scale experimental results reported by Asmussen et al.[17], and considering laboursome to prepare the computer input data, the following suggestions can safely be made; (a) Use of $K_o$ in ship vibration analysis is appropriate in practical senses. (b) Use of $K_c$ is appropriate even for detailed vibration analysis of a ship's hull. (6) The effective shear area based on the projected area method is acceptable for the two-node mode.

• 한국진공학회지
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• 제19권1호
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• pp.10-13
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• 2010

본 논문은 N-face n-type GaN 표면에 산소 플라즈마 처리에 의해서 오믹전극과 접촉 저항을 낮추기 위한 연구를 하였다. 120초 산소 플라즈마 처리후 Ti (50 nm) / Al (35 nm)을 증착한 결과 오믹 전극을 구현하였으며, $1.25{\times}10^{-3}\;{\Omega}cm^2$의 접촉저항을 보였다. 이는 산소 플라즈마 처리가 기존의 플라즈마 처리와 같이 질소결원이 발생하였기 때문이다. 이를 통해 쇼트키장벽 높이(SBH)이 낮아지게 되었고, 오믹 전극및 플라즈마 처리를 안 한 경우보다 더 낮은 접촉저항의 결과를 획득하였다.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.502-508
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• 2002

The strains of Panax ginseng C.A. Mey., P. quinquefolius L. and selected strains P. ginseng-B, P.ginseng-A, P. quinquefolius-C were investigated. Activities of SOD, catalase and peroxydase were determined by methods of Fridovich et al. (1979), Komov et al.(1975), Bovaird et al.(1982) respectively. Activities of SOD, catalase, peroxydase were investigated every day 5 in cycle of cultivation. For P. ginseng it was the 35 days, P. quinquefolius the 70 days, P. quinquefolius-C 90 days. P. ginseng-B 90 days, P. ginseng-A 60 days. The P. quinquefolius, P. quinquefolius-C, P. ginseng-B had clear differentiation and developed tracheid elements, which are absent in strain of P. ginseng. The peaks of protein content for P. ginseng (4.5 units/g) and for P. quinquefolius (3.5 units/g) were on day 10 and remained unchanged till the last cultivation. The strain P. ginseng-A had two peaks of protein content (2.5 mg/g) on day 15 and on day 30. For P. ginseng-B strain these peaks were on day 5 and day 40 (3.5 mg/g). Peroxydase activity peak (60 units/g) in P. ginseng strain was on day 10. This activity in P. ginseng-B had two peaks on day 15 and day 35 and reached 95 units/g , increasing to 150 units/g to day 80. In strain of P. ginseng-A was only one maximum of this activity -130 units/g on day 45. In P. quinquefolius peroxydase activity was 103 units/g on day 40, increasing to 135 units/g to day 90. For P. quinquefolius-C this activity peak was 136 units/g on day 60. Peroxydase activities for the upper and lower layers of biomass was different and varied considerably from 28-35 units/g in lower to 270-290 units/g for upper layer. The SOD activity had two peaks in P. ginseng strain the 80 units/g and the 70 units/g on day 20 and day 35 respectively. Activity of SOD in P. quinquefolius strain reached 53 units/g on day 40 and increased up to 83 units/g to day 60.The similar increase of SOD activity was marked for P. ginseng-B to 85 units/g on day 90. In P. ginseng strain the 6 molecular isoforms SOD was defined. One of them with RfO,6 was determined in all days of cycle, three other (Rf-0.43; 0.54;0.80) only on day 10 and day 20. The isoform of SOD with Rf-0,29 was detected only on day 10 and with Rf-0,35 only on day 35. The catalase activity decreased in all strains to the last days of cultivation. The changes of SOD, catalase and peroxydase activities reflect the differences between the strains of Panax ginseng and Panax quinquefolius and their selected forms. The correlation between maximum life span of strains and activities of their antioxydant enzymes were detected.

• 한국광물학회지
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• 제11권1호
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• pp.1-12
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• 1998

In Pohang area, basaluminite accompanying a little amounts of hydrobasalumnite, super-genetically occurs as whitish cryptocrystalline (2-4 $\mu\textrm{m}$) clay-like aggregates in the vicinity of altered carbonate concretions embedded within mudstones of the Tertiary Yeonil Group. A hydrobasaluminite changed readily into a basaluminite at room temperature in air, and, in turn, into a metabasaluminite when heating to 150$^{\circ}$~30$0^{\circ}C$. For the basaluminite, a monoclinic unit-cellparameters (a=14.845$\AA$, b=10.006$\AA$, c=11.082$\AA$, $\beta$=122.15$^{\circ}$) were calculated by X-ray powder diffraction data. Its basal reflections (001 and 002) are XRD analyses strongly indicate that the aluminum sulphate mineral has a layer structure and, at least, three types of water, i.e., (1) interlayer water (9.0 wt %), (2) crystal water (8.0 wt %), and (3) structural water (19.0 wt %). may present in its lattice. Based on TG-DTG data combined with EDS and IR analyses, a new chemical formula of Al5SO4(OH)134H2O was given to the basaluminite. Field occurrence and stable isotope data ($\delta$18O, $\delta$D, $\delta$34S) for the basaluminite seem to reflect that it was formed by the leached meteoric solution from surrounding mudstones during or after uplifting. An interaction of the acid solution with carbonate concretion and the resultant local neutralization of the fluid rich in Al3+ and SO42- are major controls on the basaluminite formation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.69-69
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• 2000

(Ba, Sr)TiO3 (BST)[1-3] 박막은 유전상수가 크고 고주파에서도 유전특성 저하가 적기 때문에 ULSI DRAM(Dynamic Random Access Memory)에 응용 가능한 물질로 최근 각광을 받고 있다. 하지만, 아직 BST 박막을 DRSM에 바로 적용하기 위해선 몇 가지 문제점이 있다. 그 중 누설전류 문제는 디바이스 응용시 매우 중요한 요소이다. 특히, DRAM에서 refresh time와 직접적인 관련이 있어 디바이스 내의 신뢰도 및 전력소모를 결정하는 주된 인자가 된다. 지금까지, BST 박막의 인가전업, 온도, 그리고 전극물질에 따른 누설전류 현상들이 고찰되었고, 이에 관한 많은 전도기구 모델들이 제시되었다. Schottky emission, Poole-Frenkel emission, space charge limited conduction 등이 그 대표적인 예이다. 하지만 아쉽게도 BST 박막의 정확한 누설 전류 전도 기구를 완전히 설명하는데는 아직 한계가 있다. 따라서 본 연구에서는 제작된 BST 커패시터 내의 기본적인 전기적 성질을 조사하고, 정확한 누설전류 기구 규명에 초점을 두고자 한다. 이를 위해 기존의 여러 기구들과 비교 분석할 것이다. 하부전극으로 사용하기 위해 스퍼터링 방법으로 p-Si(100) 기판위에 RuO2 박막을 약 120nm 증착하였다. 증착전의 chamberso의 초기압력은 5$\times$10-6 Torr이하의 압력으로 유지시켰다. Ar/O2의 비는 이전 실험에서 최적화된 9/1로 하였다. BST 박막 증착 시 5분간 pre-sputtering을 실시한 후 하부전극 기판위에 BST 박막을 증착하였다. 증착이 끝난 후 시편을 상온까지 냉각시킨 후 꺼내었다. 전기적 특성을 측정하기 상부전극으로 RuO2와 Al 박막을 각각 상온에서 100nm 증착하였다. 이때 hole mask를 이용하여 반경이 140um인 원형의 상부전극을 증착하였다. BST 박막의 증착온도가 증가하고 Ar/O2 비가 감소할수록 제작된 BST-커패시터의 전기적 성질이 우수하였다. 증착온도 $600^{\circ}C$, ASr/O2=5/5에서 증착된 막의 누설전류는 4.56$\times$10-8 A/cm2, 유전상수는 600 정도의 값을 나타내었다. 인가전압에 따른 BST 커패시터의 transition-current는 Curie-von Schweider 모델을 따랐다. BST 박막의 누설전류 전도기구는 기존의 Schottky 모델이 아니라 modified-Schottky 무델로 잘 설명되었다. Modified-Schottky 모델을 통해 BST 박막의 광학적 유전율 $\varepsilon$$\infty$=4.9, 이동도 $\mu$=0.019 cm2/V-s, 장벽 높이 $\psi$b=0.79 eV를 구하였다.