Convergent 열처리를 통한Nd₂₃Dy₁₀Fe₆₄TM₂B₁ 소결자석의 보자력 향상

김훈섭,김세훈,김진우,김영도,Kim, Hoon-Sup,Kim, Se-Hoon,Kim, Jin-Woo,Kim, Young-Do 한국분말야금학회 2010 한국분말재료학회지 (KPMI) Vol.17 No.1

In this study, a convergent heat treatment was performed in certain temperature regions in order to control the microstructures of Nd-rich phases and to reduce thermal stress on grain boundaries which could be caused during expansion and shrinkage of Nd-rich and $Nd_2Fe_{14}B$ phases. The difference of thermal expansion coefficient between $Nd_2Fe_{14}B$ and Nd-rich phases is the mechanism for convergent heat treatment. The Nd-rich phases which were located in junctions could penetrate into the grain boundaries between $Nd_2Fe_{14}B$ phases due to the difference of thermal expansion coefficient. Through the convergent heat treatment, the microcracks that were observed in cyclic heat treatment were not observed and coercivity was increased to 34.05 kOe at 8 cycles.

루프 미러로 구성된 기준팔을 가지는 파장 스위핑 OCT 구현

김훈섭(Kim Hoon Sup),남궁명우(Namgoong Myung Woo),이정렬(Lee Jung Ryul),엄진섭(Eom Jin Seob) 강원대학교 산업기술연구소 2007 産業技術硏究 Vol.27 No.1

As a reflector of reference arm in OCT systems, a coated fiber reflector has mostly used. Instead, this paper has realized the swaept source optical coherence tomography system using a loop mirror within a reference ann. Through the expehments for a tilted thin glass plate, we found that the loop mirror is better than the coated fiber typed mirror for obtaining the clear image.

병렬 SOA 구조의 파장가변 레이저를 이용한 단면 영상획득

김훈섭(Kim Hoon Sup),엄진섭(Eom Jin Seob) 강원대학교 산업기술연구소 2008 産業技術硏究 Vol.28 No.1

We have realized the swept source optical coherence tomography(SS-OCT) by using the self-fabricated wavelength swept laser(wavelength tuning range : 80㎚, line-width : 0.12㎚, wavelength sweeping rate : 50㎐). In addition, we have used the dual balanced detector that could make a mirror image in OCT display suppressed. We can also fabricate the comb filter of Michelson interferometer type for fast-signal processing in OCT. Using this SS-OCT system for measuring an mirror, a 1㎜-depth glass and an onion, we confirmed that the in vivo epidermal cross-sectional images for them can be obtained appropriately.

Spectral-Domain 광 계측을 위한 CCD 이미지 센서 드라이버 제작

김훈섭(Kim Hoon Sup),이정렬(Lee Jung Ryul),엄진섭(Eom Jin Seob) 강원대학교 산업기술연구소 2007 産業技術硏究 Vol.27 No.1

This paper presents Spectral-Domain optical measurement system using self-fabricated CCD sensor driver. The light source is a high brightness white LED and the detector is a 2048 array typed CCD image sensor. I have fabricated the CCD sensor driver to generate four pulse signals, which are the CCD-driving pulses. Using this Spectral Domain optical measurement system, the distance value between the reference mirror and the sample mirror can be obtained successfully.

반복 열처리한 Nd-Fe-B 소결 자석의 미세구조 제어 및 자성특성 평가

김세훈,김훈섭,김동환,김영도,Kim, Se-Hoon,Kim, Hoon-Sup,Kim, Dong-Hwan,Kim, Young-Do 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.6

Sintered Nd-Fe-B magnets have been widely used due to their excellent magnetic properties, especially for driving motors of hybrid and electric vehicles. The microstructure of Nd-Fe-B magnets strongly affects their magnetic properties, in particular the coercivity. Therefore, a post-sintering process like heat-treatment is required for improving the magnetic properties of Nd-Fe-B sintered magnets. In this study, cyclic heat treatment was performed at temperatures between $350^{\circ}C$ and $450^{\circ}C$ up to 16 cycles in order to control microstructures such as size and shape of the Nd-rich phase without grain growth of the $Nd_{2}Fe_{14}B$ phase. The 2 cycles specimen at this temperature range showed more homogeneous microstructure which leads to higher coercivity of 35 kOe than as-sintered one.

The Crystal and Molecular Structure of Piperidinothiosemicarbazide

구정회,김훈섭,장종환,Koo, Chung Hoe,Kim Hoon Sup,Chang Chong Hwan Korean Chemical Society 1975 대한화학회지 Vol.19 No.2

피페리디노티오세미카르바지드의 결정구조가 X-선을 이용한 단결정 해석에 의하여 해명되었다. 공간군은 $P2_1/c$이며 단위세포는 4분자를 포함하고 있고, 단위세포는 4분자를 포함하고 있고, 세포상수는 $a=14.68{\pm}0.04,\;b=4.59{\pm}0.02,\;c=12.92{\pm}0.04{\AA},\;{\beta}=109.4{\pm}0.2^{\circ}$이다. 3차원적인 회절반점의 강도는 목측에 의하여 얻었다. 결정구조는 패터슨 함수의 해석으로 밝혔고, 원자좌표치는 최소자승법으로 정밀화하였으며 378개의 독립적인 회절반점에 대한 최종 R값은 0.14이었다. 수소결합에는 $N-H{\cdot}{\cdot}{\cdot}S$ 형과 $N-H{\ldots}N$형의 두종류가 있다. $N-H{\ldots}S$형의 길이는 3.28 및 $3.39{\AA}$이고, $N-H{\ldots}N$형의 길이는 $3.03{\AA}$이다. 수소결합외의 분자들을 연결하는 힘은 van der Wasls힘이다. The crystal structure of piperidinothiosemicarbazide, $C_6H_{13}N_3S$, has been determined by single crystal X-ray analysis. The space group is P21/c with four molecules in the unit cell of dimensions $a=14.68{\pm}0.04,\;b=4.59{\pm}0.02,\;c=12.92{\pm}0.04{\AA}\;and\;{\beta}=109.4{\pm}0.2^{\circ}$. Three-dimensional photographic intensities were estimated visually. The structure has been solved by an interpretation of a Patterson synthesis and refined by block-diagonal least-squares methods to give a final R value of 0.14 for 378 observed independent reflections. There are two independent hydrogen bonds in the structure. One of them is of the type N-H${\ldots}$S with the length 3.28 and $3.39{\AA}$, and another is of the type N-H${\ldots}$N with the length $3.03{\AA}$. Apart from the hydrogen bonding system the molecules are held together in the crystal by van der Waals forces.

The Crytal and Molecular Structure of Morpholinothiosemicarbazide

구정회,김훈섭,신현소,이영자,Chung Hoe Koo,Hoon Sup Kim,Hyun So Shin,Yungja Lee Korean Chemical Society 1973 대한화학회지 Vol.17 No.2

몰포리노치오세미카바자이드의 결정 구조가 X-선 해석에 의하여 결정되었다. 세포 상수는 a=4.19(2), b=6.56(2), c=26.67(4)$A^{\circ}$ 이고, 단위 세포는 4분자를 포함하며, 공간 군은 $P2_12_12_1$이다. 원자좌표치는 최소자승법으로 정밀화하였으며 R값은 651개의 관측 반사를 써서 계산한 결과 0.07이다. 아미노 질소 원자는 a-축에 평행한 2회의 나선 축에 의하여 옮겨지는 다른 분자의 황원자와 3.48 및 3.49$A^{\circ}$의 수소결합을 하고 있으며 아미노 질소 원자는 a-축에 평행한 2회의 나선 축에 의하여 옮겨지는 다른 분자의 아미노 질소 원자와 3.04${\AA}$의 수소결합을 하고 있다. 이들 3개의 수소결합은 분자들을 2회의 나선축 부근에 배열하게 한다. 수소결합 이외로 분자들을 연결하는 힘은 van der waals의 힘이다. The crystal structure of morpholinothiosemicarbazide has been determined by single crystal X-ray analysis. The lattice constants are a = 4.19(2), b = 6.56(2) and c = 26.67(4)${\AA}$. The unit cell contains 4 molecules and the space group is$P2_12_12_1$. The atomic parameters have been refined by least-squares method to a final R value of 0.07, based on the 651 observed reflexions. The amino nitrogen atom forms hydrogen bonds to the sulfur atoms of the other molecules related by the two-fold screw axis parallel to the a-axis, the distances of the hydrogen bonds being 3.48 and 3.49${\AA}$. On the other hand, the imino nitrogen atom forms a hydrogen bond to the amino nitrogen atom of the other molecule related by the two-fold screw axis parallel to the a-axis, the distance of the hydrogen bond being 3.04${\AA}$. These three hydrogen bonds arrange the molecules around the two-fold screw axis. Apart from the hydrogen bonding system the structure is held together by van der Waals forces.

Nicotinic Acid Hydrochloride의 結晶構造

구정회,김훈섭,Chung Hoe Koo,Hoon Sup Kim 대한화학회 1963 대한화학회지 Vol.7 No.4

The crystal structure of nicotinic acid hydrochloride has been determined by two-dimensional x-ray method. The unit cell is monoclinic with a = 7.21 ${\AA}$, b = 6.69 ${\AA}$, c = 7.54 ${\AA}$, ${\beta}=100^{\circ}$, space group $C{\frac{2}{2}}-P2_1$, and contains two formula units. Weissenberg diagrams have been taken along the a, b and c axes with Cu K${\alpha}$ radiation and the positions of the atoms have been fixed by means of two dimensional Patterson syntheses, a Fourier projection along the b-axis and trial and error method. The bond lengths are: pyridine ring C-C = 1.38, 1.39 ${\AA}$, C-N = 1.34, 1.36 ${\AA}$, carboxyl group $C_4-C_6$ = 1.46 ${\AA}$, $C_6-O_1$ = l.33 ${\AA}$, $C_6-O_2$ = 1.19 ${\AA}$. The ring nitrogen atom may be regarded as forming bifurcated hydrogen bond with an oxygen atom $O_2$ of one neighbouring molecule and with a neighbouring chlorine atom, being linked by forming a hydrogen bond with an other oxygen atom $O_1$ of above mentioned neighbouring molecule, in such a way that chains parallel to the c-axis are formed.

The Crystal Structure of Nicotine Dihydroiodide

구정회,김훈섭,Koo, Chung-Hoe,Kim, Hoon-Sup Korean Chemical Society 1965 대한화학회지 Vol.9 No.3

니코틴 二沃化水素酸鹽의 結晶은 直角非等軸結晶係(料方晶係)에 屬하며 空間群은 $p2_12_12_1$이다. 單位格子의 크기는 a=7.61, b=11.01 및 e=17.27${\AA}$이며 單位格子안에 들어있는 化學單位의 水는 4이다. 이 結晶의 構造를 X-線廻折法에 依하여 解析하였으며 R 値 ${\sum}{\mid}{\mid}F_{\circ}{\mid}-{\mid}F_c{\mid}{\mid}{\div}{\sum}{\mid}F_{\circ}{\mid}$ 가 $F_{orl}$</Tex>와 $_{kol}$에 關하여 各各 0.16및 0.14의 값을 이룰 때까지 精密化 하였다. 原子間距離의 精密化를 試圖하지는 않았지만 피리딘 고리 안의 C-C 및 C-N의平均距離는 各各 1.40 및 $1.35{\AA}$의 값을 가진다. 피리딘 고리 內의 各原子는 實驗誤差內에서 同一平面上에 있으며 피롤리딘 고리에서는 $C_6,\;C_7,\;C_8$및$N_2$原子는 大略 同一平面上에 있으나 $C_9$는 이 平面으로 부터 約0.22${\AA}$ 떨어져있다. 피리딘 고리의 平面과 $C_6,\;C_7,\;C_8$및 $N_2$가 이루는 平面의 各法線은 約 $94^{\circ}$를 이루고 있다. 이코틴 二沃化水素酸鹽의 한 分子內의 두個의 요오드 原子中 한개는 피리딘 고리의 窒素原子와 $3.55{\AA}$의 距離로 連結되여 있으며 다른 한개는 피콜리딘 고리의 窒素原子 와 $3.58{\AA}$의 距離로 連結되여 있다. 結晶內에서 各 分子는 Van der Waals force로 서로 接燭되여 있다. Crystals of nicotine dihydroiodide, are orthorhombic with space group $p2_12_12_1$.The unit cell of dimensions a=7.61, b=11.01, e=17.27${\AA}$, contains four formula units. The structure has been determined by X-ray diffraction method and has been refined to give the R-index, ${\sum}{\mid}{\mid}F_{\circ}{\mid}-{\mid}F_c{\mid}{\mid}{\div}{\sum}{\mid}F_{\circ}{\mid}$, of 0.16 and 0.14 for $F_{okl}\;and\;F_{hol}$ respectively.The mean lengths of C-C and C-N bonds in pyridine ring are 1.40 and $1.35{\AA}$ and those in pyrolidine ring 1.56 and $1.48{\AA}$ respectively, though accurate measurement of bond length has not been attempted. The six atoms in the pyridine ring are coplanar and on the other hand $C_6,\;C_7,\;C_8$ and $N_2$ atoms in pyrrolidine ring form a plane within accuracy of the analysis, and $C_9$ atom is distant $0.22{\AA}$ out of the plane consist of $C_6,\;C_7,\;C_8$ and $N_2$ aoms. The normals to the two planes form an angle of $94^{\circ}$ with each other. Iodine atom is distant $3.55{\AA}$ from nitrogen atom in pyridine ring and the other iodine atom $3.58{\AA}$ from nitrogen atom in pyrrolidine ring, so that the nitrogen and iodine atoms are firmly linked.It seems that the only forces binding nicotine dihydroiodide molecules together in the crystal are Van der Waals forces.

Benzidine 鹽酸鹽의 結晶構造

구정회,김훈섭,신현소,Koo, Chung-Hoe,Kim, Hoon-Sup,Shin, Hyun-So 대한화학회 1972 대한화학회지 Vol.16 No.1

Benzidine dihydrochloride crystallizes in the triclinic system. The space group is $P_1$. The unit cell dimensions are; a = 4.38${\pm}$0.01, b = 5.76${\pm}$0.01, c = 12.82${\pm}$0.02${\AA}$, $\alpha$ = 101.5${\pm}$0.2, $\beta$ = 99.5${\pm}$0.2, $\gamma$ = 99.5${\pm}$0.2$^{\circ}$; with one molecule per unit cell. The crystal structure has been solved by two dimensional Patterson and by trial and error methods, and refined by means of two dimensional differential synthesis. The bond distances are C-C(*) = 1.40${\pm}$0.02, C-C = 1.52${\pm}$0.02, C-N = 1.51${\pm}$0.03 and N-H${\cdot}{\cdot}{\cdot}$Cl = 3.21${\pm}$0.03${\AA}$. The structure consists of hydrogen bonded molecular layers, extending to the (100) plane, and the hydrogen bonding scheme is similar to that of p-phenylenediamine dihydrochloride. The adhesion between hydrogen bonded molecular layers is due to van der Waals forces.