• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.25 no.1
• /
• pp.55-68
• /
• 1999

A muti-lamellar emulsion containing a pseudoceramide, N-Ethanol-2-myristyl/ palmityl-3-oxostearmide/arachidamide(PC-9) has been prepared and its efficacy evaluation has been investigated. In order to prepare a muti-lamellar emulsion, first, the gram ratios of PC-9, fatty acid and cholesterol on the phase diagram to be capable of forming their lamellar liquid crystal structures were determined and secondly, the multi-lamellar emulsion was preprared using glyceryl monostearate and polyoxyethylene glyceryl monosteartate as emulsifers together with above mentioned pseudo-stratum corneum lipid components. Besides natural oils such as olive oil had a tendency to build up the multi-lamellar emulsion. And according as the amount of oil increased in the emulsion, it was observed that the optical anisotropy of “Maltese Cross” which was a typical configuration of multi-lamella mesophase texture diminished. In the dried state of the multi-lamella emulsion, it was examined to transform its emulsion phase into a lamella liquid crystal one. And finally, when the emulsion was applied into a human skin, it was investigated that it had effectiveness in reducing transepidermal water loss (TEWL) of the skin.

• The Journal of the Petrological Society of Korea
• /
• v.24 no.3
• /
• pp.153-164
• /
• 2015

Jurassic granite from Geochang was analysed with respect to the characteristics of the rock cleavage. we have mainly discussed the structual anisotropy formed by microcracks. The phases of distribution of microcracks were well evidenced from the enlarged photomicrographs(${\times}6.7$) of the thin section. The planes of principal set of microcracks are parallel to the rift plane and those of secondary set are parallel to the grain plane. These rift and grain microcracks are mutually near-perpendicular on the hardway planes. From the directional angle(${\theta}$) - total length($L_t$), number(N) and density(${\rho}$) chart, the curve patterns of the above microcrack parameters reflect the phases of distribution of microcracks. Microcrack parameters such as number, length and density show an order of rift > grain > hardway. These results indicate a relative magnitude of the rock cleavage. Meanwhile, brazilian tensile strengths were measured with respect to the six directions. The results revealed a strong correlation between mechanical property with the above microcrack parameters. These general results correspond to those of the previous study for Jurassic granites from Pocheon and Hapcheon. Image processing technique for the enlarged photomicrograph of the thin section was carried out. The grain 1(G1) microcrack arrays developed in quartz and feldspar grains show excellent distribution on the photomicrograph. In particular, the directional angle of each microcrack set can be ascertained easily by brief image processing for the above photomicrograph.

• Journal of the Korean Magnetics Society
• /
• v.16 no.1
• /
• pp.40-44
• /
• 2006

[ $Zn_{0.5}Ni_{0.5}Fe_2O_4$ ] nanoparticles have been prepared by a sol-gel method. The structural and magnetic properties have been investigated by XRD, SEM, and Mossbauer spectroscopy, VSM. $Zn_{0.5}Ni_{0.5}Fe_2O_4$ powder that was annealed at $300^{\circ}C$ has spinel structure and behaved superparamagnetically at room temperature. The estimated size of superparammagnetic $Zn_{0.5}Ni_{0.5}Fe_2O_4$ nanoparticle is around 7 nm. The hyperfine fields of the A and I patterns at 4.2 K were found to be 510 and 475 kOe, respectively. The blocking temperature $(T_B)$ of superparammagnetic $Zn_{0.5}Ni_{0.5}Fe_2O_4$ nanoparticle is about 90 K. The magnetic anisotropy constant and relaxation time constant of $Zn_{0.5}Ni_{0.5}Fe_2O_4$ nanoparticle were calculated to be $K=1.6\times10^6erg/cm^3$.

• Journal of the Korean Magnetics Society
• /
• v.10 no.5
• /
• pp.196-202
• /
• 2000

Top synthetic spin valves with structure Ta/NiFe/CoFe/Cu/CoFe(P1)/Ru/CoFe(P2)/FeMn/Ta on Si(100) substrate with natural oxide were prepared by dc magnetron sputtering system, and investigated on the magnetoresistance properties and effective exchange bias field. As the thickness of FeMn increased above 150 $\AA$, MR ratio was decreased due to the current shunting effect. As the thickness of free layer decreased below 40$\AA$, MR ratio was reduced rapidly. In case of 40 $\AA$ thick of free layer, spin valve film with a structure Si(100)/Ta(50 $\AA$)/NiFe(27 $\AA$)/CoFe(13 $\AA$)/Cu(26 $\AA$)/CoFe(30 $\AA$)/Ru(7 $\AA$)/CoFe(15 $\AA$)/FeMn(100 $\AA$)/Ta(50 $\AA$) exhibited maximum MR ratio of 7.5 % and an effective exchange bias field of 600 Oe, respectively. Thickness difference dependence in this synthetic spin valve structure on effective exchange field was investigated and interpreted by the analytical method. It should be noted that thickness increase of CoFe(P 1) and decrease of CoFe(P2) in synthetic antiferromagnet leaded to the decrease in effective exchange bias field by experimentally and analytically.

• Journal of the Korean Magnetics Society
• /
• v.25 no.1
• /
• pp.10-15
• /
• 2015

The model for the magneto-impedance of composite wires composed of highly conductive nonmagnetic metal core and soft magnetic shell was derived based on the Maxwell's equations. The Cu($100{\mu}m$ diameter)/$Ni_{80}Fe_{20}$($15{\mu}m$ thickness) core/shell composite wire was fabricated by electrodeposition. The impedance spectra for the $Cu/Ni_{80}Fe_{20}$ core/shell composite wire were measured in the frequency range of 10 kHz~10 MHz under longitudinal dc magnetic field in 0 Oe~200 Oe. The spectra of complex permeability in circumferential direction were extracted from the impedance spectra by using the derived model. The extracted spectra of complex permeability showed relaxation-type dispersion which is well curve-fitted with Debye equation with single relaxation frequency. By analyzing the magnetic field dependence of the complex permeability spectra, it has been verified that the composite wire has magnetic anisotropy in longitudinal direction and the origin of the single relaxation process is the magnetization rotation in circumferential direction.

• Korean Journal of Veterinary Research
• /
• v.1 no.1
• /
• pp.1-29
• /
• 1961

A routine hematological observation in the course of starvation was carried out on eight experimentel1y starved rabbits. They were strictly selected and restricted all of food intake with the exception of optional water intake until death. The body weight of each rabbit on the day before starvation was about 2 kilograms. The results are summarized as follows. 1. The average decrememt ratio of body weight on the terminal day before death was $34.3{\pm}7.5$ per cent with the range from 24.5 to 46.3 per cent. The average life duration until death was $10.25{\pm}2.6$ days, the range being from 6 to 14 days. 2. The decrease in number of reticulocytes with a parallel disappearance of polychromatic erythrocytes in peripheral blood in the course of starvation Was the most remarkable change in erythrocytic series, an evidence suggesting marked restriction of the erythropoietic function on 3rd to 4th day and almost complete suspension in about a week of starvation. 3. Erythrocyte count, hemoglobin content and haematocrit value of peripheral blood, were normal or indicative of slight hemoconcentration. 4. Mean Corpuscular Hemogloin Concentration was slightly higher than normal and Mean Corpuscular Volume tended to be low and no appreciable shifts were observed in Mean Corpuscular Diameter and Price-Jones curve of erythrocytes, while fewer macrocytes than normal were seen. These changes were considered to have resulted from a marked decrease in young erythrocytes in peripheral blood in the course of starvation. 5. Neither poikilccytoses or anisosytosis was observed. 6. Leukopenia was observed in all of 8 starved rabbits. The decrement ratio on the terminal day of starvation was between 13 to 64 per cent. The leukopenia was mainly due to fall of lymphocytes in 6 cases and to fall of neutrophilic leukocytes in the other 2 cases. In many cases, irregular fluctuation of neutrophilic leukocytes in its biological curve were seen in contrast to the relatively smooth changes of lymphocytes. Eosinophilic leukocytes tended to decrease in absolute number especially in later stage of starvation. Little significance in regard to monocytes and basophilic leukocytes in this study was discussed. 7. Proplasma cells, rarely plasma cells, appeared with a tendency to increase in number at later stage of starvation. 8. The most characteristic changes on circulating blood cells in complete starvation of rabbits were the leukoponia and failure of regeneration of erythroctes. These changes were considered as adaptive phenomena in response to the catabolic consumption of body constituents.

• Korean Journal of Veterinary Research
• /
• v.25 no.2
• /
• pp.91-101
• /
• 1985

This study was conducted in order to observe the changes in cellular associations of seminiferous tubules from 8 to 20 weeks of age and to obtain the cycle and relative duration of the seminiferous epithelia from 24 to 32 weeks of age. Twenty-eight Korean native male goats were used in the experiment and divided into 7 groups, consisting of 4 goats each, with four weeks intervals from 8 to 32 weeks of age. The results were summarized as follows; 1. Gonocytes were seen at 8 weeks of age, however they were not observed as from 12 weeks. Both type A-spermatogonia and type B-spermatogonia occurred from 8 weeks, while primary spermatocytes were found from 12 weeks. Secondary spermatocytes and spermatids appeared from 16 weeks, and increased in numbers sequentially until 32 weeks of age. Spermatozoa were observed at first at 20 weeks of age. 2. Type A-spermatogonia appeared approximately twice as many at stage 2 as compared to stage 1, while the same numbers of cells were seen in both stages 1 and 8, showing the least number among 8 stages of the cycle of the seminiferous epithelia. The type B-spermatogonia were found during the stage 5 to 8, not to be detactable during stage 1 to 4. The number of primary spermatocytes of the leptotene phase increased markedly during stage 1 to 4, and decreased afterwards. The primary spermatocytes of the pachytene phase were shown the least in number at stage 4. The secondary spermatocytes could be seen only at stage 4 and the largest number of spermatids was seen at the stage 4 among 8 stages. 3. The relative frequencies of each stage among stages 1 to 8 of the cycle of the seminiferous epithelia were 27.5, 17.5, 12.8, 5.8, 8.9, 8.3, 12.0 and 7.2% respectively. 4. Some of the nuclei of Sertoli cells transformed from the "parallel" type to the "perpendicular" type. This evolution took place from stage 1 to 6, when the number of "perpendicular" type nuclei reached a peak and the number was decreased in the rest of the stages. Thus, establishment of spermatogenesis in Korean native goats was completed at the age of 20 weeks.

• Journal of the Mineralogical Society of Korea
• /
• v.18 no.3 s.45
• /
• pp.147-153
• /
• 2005

Naldrettite, recently discovered in the Mesamax Northwest deposit, Ungava region, northern Quebec, Canada, was reported as a new mineral. In order to confirm whether itis a natural equivalent of synthetic $Pd_2Sb$ phase or not, the pure $Pd_2Sb$ phase has been synthesized and investigated by reflected microscope, electron microprobe analyser, X-ray diffractometer, and micro-indentation hardness tester. Under reflected light synthetic $Pd_2Sb$ Phase is white with a creamy tint in both air and oil and weakly bireflectant. Anisotropism is strong, from brownish gray to greenish blue in air. Micro-indentation hardness test gives VHN100=293(242-322). Composition of the phase is $63.7\~64.3wt.\%\;Pd\;and\; 36.4\~36.8wt.\%$ Sb, and is entirely consistent. The phase, quenched from $500^{\circ}C$, is orthorhobic with space group $Cmc2_1$, and the cell parameters are a=3.366(1), b=17.523(3), c=6.929(2) ${\AA}$. All mineralogical properties of synthetic $Pd_2Sb$ compare very well with those of naldrettite, confirming that naldrettite is the natural analogue of the synthetic $Pd_2Sb$ phase.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2002.04b
• /
• pp.45-45
• /
• 2002

나노미터 크기의 결정립을 가지는 나노분말 및 나노복합분말의 제조와 특성에 관한 연구가 매우 활발하다. 나노복합분말의 제조방법에는 기상증발후 응축법, 화학응축법, 기계적합금법 등이 있으나, 고순도 및 균일한 크기분포의 분말과 응집되지 않은 분말의 제조 조건을 가장 잘 만족하는 방법은 화학기상응축법(Chemical Vapor Condensation; CVC)이다. 본 연구그룹 에서는 CVC밤법으로 이용하여 공구/금형재료에 가장 많이 사용되는 WC/Co 합금의 결정립을 n nm크기로 극미세화고자하는 연구을 진행하고 있다. 본 연구에서는 이들 WC/Co합금제조시 가장 중요한 출발분말인 나노크기 WC 분말의 제조와 그 특성에 관하여 연구하고자 하였다. 나노미터 WC분말을 제조하기 의한 전구체는 고상의 금속유기물인Tungstenhexacarbonyl$(W(CO)_6)$ 을 사용하였다. 수평관상로을 반응기로 사용하였으며, 노내의 온도을 500-110$0^{\circ}C$로 변화시 키면서 WC 분말을 합성하였다. 반응기 및 포집기 내부를 대기분위기, 상압의 Ar분위기, 진공 분위기로 변화시켜 압력 및 분위기의 영향을 조사하였다. 포집기는 상온 및 액체질소로 냉각 한 Chiller을 사용하였다. 형성분말의 상분석은 XRD로 조사하였으며, 형태 및 결정립크기는 TEM로 분석하였다. 반응온도 600 -1 OOO$^{\circ}C$의 온도범위에서 검은색의 WC 분말이 제조되었다. XRD 분석의 결과 로 제조된 분말은 상온에서 준안정상인 Hexagonal 구조의 $\gammar-WC_{1-x}$ 상이였으며, TEM 분석결 과 상압하에서는 약 30nm이하의 WC분말이 제조되었으며, 그 형태는 둥근 4각형의 모양을 지녔다. 감압하에서 진행한 경우 결정립의 크기는 8nm이하를 가졌다.곤가스로 산화를 방지하였고, 냉매로는 질소가스를 이용하였다. 제조된 분말을 기ㅖ적 분급법을 이용하여 분급하였고, 냉매로는 질소가스를 이용하였다. 제조된 분말을 기계적 분급ㅂ법을 이용하여 분급하였고, 압출에 이용된 분말은 250$\mu\textrm{m}$이하의 크기를 사용하였다. 또한 분말제조과정 중 형성되는 표면산화층을 제거하기 위하여 36$0^{\circ}C$에서 4시간동안 수소 환원처리를 행하였다. 제조된 분말은 열간 압출을 위하여 Aㅣcan에 넣고 냉간성형체를 만들고, 진공처리를 한 후 밀봉하여 탈가스처리를 하였다. 압출다이는 압출비가 각각 28:1과 16:1인 평다이(9$0^{\circ}C$)를 사용하여 각각 내경이 9, 12cm이고, 길이가 50, 30cm인 압출재를 제조하였다. 열간압출한 후의 미세조직을 광학현미경으로 압출방향에 평행한 방향과 수직방향으로 관찰하였고, 열간 압출재 이방성을 검토하기 위하여 X선 회절분석을 실실하여 결정방위를 확인하였다. 전기 비저항 및 Seebeck 계수 측정을 위하여 각각 2$\times$2$\times$10$mm^3$ 그리고 5$\times$5$\times$10TEX>$mm^3$ 크기의 시편을 준비하였다.준비하였다.전류를 구성하는 주요 입자의 에너지 영역(75~l13keV)에서 가장 높은(0.80) 상관계수를 기록했다. 넷째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가 있음을 시사한다.se that were all low in two aspects, named "the Nonsign

• Journal of Biomedical Engineering Research
• /
• v.25 no.1
• /
• pp.43-47
• /
• 2004

Interests in human brain functionality and its connectivity have much frown up. DTI (Diffusion tensor imaging) has been known as a non-invasive MR) technique capable of providing information on water diffusion in tissues and the organization of white matter tract. Thus. It can provide us the information on the direction of brain fiber tract and the connectivity among many important cortical regions which can not be examined by other anatomical or functional MRI techniques. In this study. was used the 24 bit color coding scheme on the IDL platform in the windows environment to visualize the orientation of major fiber tracts of brain such as main association, projection, commissural fibers and corticospinal tracts. We additionally implemented a color coding scheme for each directional component and FA (fractional anisotropy), and used various color tables for them to be visualized more definitely. Consequently we implemented a fancy and basic technique to visualize the directional information of fiber tracts efficiently and we confirmed the feasibility of the 24 bit color coding scheme in DTI by visualizing main fiber tracts.