• Tribology and Lubricants
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• 제32권5호
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• pp.141-146
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• 2016

The diketopyrrolopyrrole (DPP) pigment is a bicyclic 8-π-electron system containing two lactam units. Typical DPP derivative pigments have melting points of over 350°C and very low solubility in most solvents, and show absorption in the visible region with a molar extinction coefficient of 33,000 dm²mol⁻¹ and strong photoluminescence with maxima in the range 500–600 nm. X-ray structure analyses of DPP show that the whole molecule is almost in one plane. The phenyl rings are twisted out of the heterocyclic plane and the intermolecular hydrogen bonding between neighboring lactam NH and carbonyl units influences the structure of the DPP pigment in the solid state. In this study, mono-N-alkylation and mono-N-arylation were undertaken for Pigment Red 264 or Pigment Orange 73 with alkyl halide and aryl halide, respectively, in the presence of sodium tert-butoxide as a base catalyst to improve the solubility of DPP pigments and their application as CO₂ indicators. The synthetic yield was in the range 11–88%. The indicator dyes are highly soluble in organic solvents and shows pH-dependent absorption (λ_max 501 and 572 nm for the protonated and deprotonated forms, respectively) and emission (λ_max 524 and 605 nm for the protonated and deprotonated forms, respectively) spectra. The mono-N-alkylated and mono-N-arylated DPP pigment was identified by ¹H-NMR (¹H-Nuclear Magnetic Resonance Spectrometer), FT-IR (Fourier Transform Infrared Spectroscopy), and MS (Mass Spectrometry). According to the results of color and hue properties obtained by a color matching analyzer, the synthesized DPP pigment material can be used as a CO₂ indicator.

• 한국재료학회지
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• 제1권4호
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• pp.206-213
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• 1991

PbO 77-80wt%, ZnO 4.5-6wt%, $B_2O_3$ 7.5-8.5wt%, $TiO_2$ 3-7wt%, $P_2O_5$ 0.5-2wt%의 조성을 갖는 IC Package봉착용 저융점($400-460^{\circ}C$) 결정화유리 frit를 제조하였다. DTA-TMA, X-선 회절분석, SEM 등을 이용하여 봉착용 유리의 결정화 특성을 연구하였다. $TiO_2$ 함량이 3wt% 함유시료는 $420-440^{\circ}C$에서 $2PbO{\cdot}ZnO{\cdot}B_2O_3$의 결정이 균일성장하였다. $TiO_2$ 함량이 4wt% 첨가된 시료는 $420-440^{\circ}C$에서 $2PbO{\cdot}ZnO{\cdot}B_2O_3와\;PbTiO_3$ 결정이 섞여서 혼합결정을 이루고 있었다. 또한 $TiO_2$ 5wt% 첨가된 시료는 $440-460^{\circ}C$에서 perovskite $PbTiO_3$ 결정만 석출되었다.

• 한국항공우주학회지
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• 제38권11호
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• pp.1087-1093
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• 2010

열관(HP)과 상변화물질(PCM)을 병렬로 배열한 일체형 위성 열제어 H/W를 제안하였다. HP-PCM 모듈은 제한적인 의미에서 일종의 off-the-shelf 부품으로써, PCM을 위한 별도의 열설계와 형상설계 등을 수행하지 않더라도 기존에 사용하고 있는 HP처럼 크기나 개수 등만을 설계함으로써 온도제어를 달성할 수 있도록 하였다. 주기적인 발열이 있는 부품의 온도제어를 위하여, 제안한 HP-PCM 모듈이 적용된 위성 방열판을 설계하고 상세모델을 수립하여 수치해석을 수행하였다. 각각 PCM이 없는 경우와 PCM을 장입한 경우에 대하여 수치해석을 수행하였으며, 등가평균값의 주기적인 변화에 대한 비교분석을 통하여 PCM의 축열과 방열에 의한 열분산이 매우 효과적임을 확인하였다. HP가 작동하지 않는 경우에 대한 수치해석을 통하여 열전도도가 작은 PCM의 사용한계를 제안한 HP-PCM 모듈을 이용하여 극복할 수 있음을 확인하였다.

• 한국식품조리과학회지
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• 제2권1호
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• pp.11-16
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• 1986

제조된 지 1개월 이내의 국산 마가린 12가지를 임의로 선택하여 이들의 물리화학적 성질과 지방산 조성을 측정하였다. 마가린은 평균 15.0%의 수분을 함유하고 있었고, 지방 함량은 평균 77.92%이었다. 융점은 평균 $36.18^{\circ}C$로써 $^33.23~42.13{\circ}C$ 의 넓은 분포를 보여 제품간의 차이가 심했다. 산가, 과산화물가 등도 모두 매우 낮게 나타났다. 요오드가는 59. 65~86. 05의 넓은 분포를 보였다. 포장형태에 따라 임의로 분류했던 연질형과 경질형 마가린들은, 집락분석 결과 지방산 조성에 따라서도 같은 두 그룹으로 분류되어, 이들의 원료에 차이가 있음을 유추할 수 있었다. 연질형 마가린은 올레산(18:1)을, 경질형 마가린은 팔미트산(16:0)을 가장 많이 함유하고 있었다. 필수지방산 함량은 제품에 따라 큰 차이를 나타냈는데, 리놀렌산(18:2)의 평균함량은 13. 11%로 나타났으나 대부분의 마가린들은 리놀렌산(18:3)을 거의 함유하고 있지 않았다. 과거보다 마가린의 필수지방산 함량은 증가하였으나, 아직 구미 각 국의 수준에는 못 미치는 것이었다.

• 한국표면공학회지
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• 제36권3호
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• pp.229-233
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• 2003

Boron-Carbon-Nitrogen (B-C-N) system is an attractive ternary material since it has not only an extremely high hardness but also a number of other prominent characteristics such as chemical inertness, elevated melting point, and low thermal expansion. In this paper, the corrosion behavior of B-C-N thin films in aqueous solution was investigated B-C-N films with different composition were deposited on a platinum plate by magnetron sputtering in the thickness range of 150-280 nm. In order to understand effect of pH of solutions, $BC_{2.\;4}N$ samples were immerged in 1M HCl, 1M NaCl, and 1M NaOH solution at 298k, respectively. BCN samples with different carbon contents were exposed to 1M NaOH solutions to investigate effect of chemical composition on corrosion resistance. Corrosion rates of samples were measured by ellipsometry, From results, optical constant of $BC_{2,\;4}N$ films was found to be $N_2=2.110-0.295i$. The corrosion rates of $Bi_{1.\;0}C_{2.\;4}N_{1.\;0}$ films were NaOH>NaCl>HCl in orders. With increasing carbon content in B-C-N films, the corrosion resistance of B-C-N films was enhanced. The lowest corrosion rate was obtained for $B_{1.\;0}C_{4.\;4}N_{1.\;9}$ film.

• Fisheries and Aquatic Sciences
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• 제19권8호
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• pp.33.1-33.7
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• 2016

Antifreeze proteins (AFPs) lower the freezing point but not the melting point of aqueous solutions by inhibiting the growth of ice crystals via an adsorption-inhibition mechanism. However, the function of type IV AFP (AFP IV) is questionable, as its antifreeze activity is on the verge of detectable limits, its physiological concentration in adult fish blood is too low to function as a biological antifreeze, and its homologues are present even in fish from tropic oceans as well as freshwater. Therefore, we speculated that AFP IV may have gained antifreeze activity not by selective pressure but by chance. To test this hypothesis, we cloned, expressed, and assayed AFP IV from cultured subtropical olive flounder (Paralichthys olivaceus), which do not require antifreeze protein for survival. Among the identified expressed sequence tags of the flounder liver sample, a 5'-deleted complementary DNA (cDNA) sequence similar to the afp4 gene of the longhorn sculpin was identified, and its full-length cDNA and genome structure were examined. The deduced amino acid sequence of flounder AFP IV shared 55, 53, 52, and 49 % identity with those of Pleuragramma antarcticum, Myoxocephalus octodecemspinosus, Myoxocephalus scorpius, and Notothenia coriiceps, respectively. Furthermore, the genomic structure of this gene was conserved with those of other known AFP IVs. Notably, the recombinant AFP IV showed a weak but distinct thermal hysteresis of $0.07{\pm}0.01^{\circ}C$ at the concentration of 0.5 mg/mL, and ice crystals in an AFP IV solution grew star-shaped, which are very similar to those obtained from other polar AFP IVs. Taken together, our results do not support the hypothesis of evolution of AFP IV by selective pressure, suggesting that the antifreeze activity of AFP IV may have been gained by chance.

• 한국전기전자재료학회논문지
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• 제13권4호
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• pp.349-358
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• 2000

Fabrication and Characterization of Bi$_{2}$/Sr$_{2}$/CaCu$_{2}$/O$_{8}$(Bi2212) superconductor thick films were fabricated successfully on C tapes by liquid reaction between Cu-free precursors of Bi$_{x}$/SrCaO/$_{y}$(x=1.2-2) and Cu tapes. Cu-free Bi-Sr-Ca-O powder mixtures were screen-printed on Cu tapes and heat-treated at 850-87$0^{\circ}C$ for several minutes in air oxygen nitrogen and low oxygen pressure. In order to obtain the optimum heat-treatment condition we studied the effect of the precursor composition the printing thickness and the heat-treatment atmosphere on the superconducting properties of Bi2212 films and the reaction mechanism. Microstructures and phases of thick films were analyzed by films and the reaction mechanism. Microstructures and phases of thick films were analyzed by optical microscope and XRD. The electric properties of superonducting films were examined by the four probe method. At heat-treatment temperature the thick films were in a partially molten state by liquid reaction between CuO of the oxidized copper tape and the precursors which were printed on Cu tapes. During the heat-treatment procedure Bi2212 superconducting particle nucleate and grow in preferred orientations.ons.s.

• Korean Journal of Acupuncture
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• 제22권2호
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• pp.127-149
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• 2005

This study is designed to investigate the method of manufacturing herbal acupuncture through literature of oriental medicine. The findings of this study are as follows; 1. The methods of manufacturing herbal acupuncture go through the process of abstraction, purification, mixing, filtration, putting and tight sealing in the container, sterilization, quality control, printing and packing 2. There are many ways to manufacturing herbal acupuncture, for example water-alcohol precipitation, alcohol-water precipitation, liquid-liquid abstract, acid-base abstract, metal base precipitation, distillation, molecular structure, polyamide absorption, dialysis, and ion exchange, etc. And popular method is water-alcohol precipitation. This is through alcohol precipitate extracting the principal ingredients from water abstraction. This is very simple and efficient way using melting characteristics of compounds in herb to water and ethanol. 3. Sterilization of herbal acupuncture is through heating-pressure, boiling, steam flowing, low temperature, filtering, radiation, cooling, and microwaves. Nowadays filtering is commonly used. And sterilization is estimated by an examination of asepsis . 4. Herbal acupuncture must be undergo study and experiment to clinical use. The problems of herbal acupuncture are turbidity, instability, causing hemolysis, pain, and fever. So many provisions (addition, sterilization, and filtration etc.) must be prepared. 5. The theory of manufacturing herbal acupuncture is from oriental medicine, not western. So it must be corresponded to oriental medical theory, for example Gimi(氣味), Guigyung(歸經), Ingyung(引經), Bosa(補瀉), and Match of Herb. It is recommended that further study of many other sided investigations in the future.

• 한국재료학회지
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• 제20권10호
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• pp.524-534
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• 2010

Glass was fabricated using refused coal ore obtained from the Dogye coal mine in Samcheok. We additionally used soda ash and calcium carbonate to make a glass with the chemical composition of soda-lime glass, and we also used white, brown, and green glass cullet to make various kinds of colored glass. Transparent glass was fabricated by melting batch materials including refused coal ore at $1550^{\circ}C$ for 1 hr in an electrical furnace. The light transmittance and color chromaticity were measured by a UV/VIS/NIR spectrometer. Transparent glass with a light transmittance of over 80% was fabricated using normal refused coal ore and white glass cullet. Various kinds of colored glass with a light transmittance of 30-80% were fabricated using refused coal ore and brown or green glass cullet. The light transmittance of the mixed color glass samples, fabricated using normal refused coal ore and brown glass cullet and green glass cullet, indicated 30-47%, a relatively low value, in the condition of a cullet ratio of 20-50%. The characteristics of the color chromaticity of the glass samples were indicated in a chromaticity diagram by x-coordinates, y-coordinates, Y (lightness). The values of x-coordinates and y-coordinates were moved with a regular directional property according to the kind and amount of glass cullet. Therefore, we concluded that refused coal ore can be used for raw materials of color glass products like art glass and glass tile.

• 한국재료학회지
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• 제27권7호
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• pp.386-391
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• 2017

Using a customized diffusion bonder, we executed diffusion bonding for ring shaped white gold and red gold samples (inner, outer diameter, and thickness were 15.7, 18.7, and 3.0 mm, respectively) at a temperature of $780^{\circ}C$ and applied pressure of 2300 N in a vacuum of $5{\times}10^{-2}$ torr for 180 seconds. Optical microscopy, field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) were used to investigate the microstructure and compositional changes. The mechanical properties were confirmed by Vickers hardness and shear strength tests. Optical microscopy and FE-SEM confirmed the uniform bonding interface, which was without defects such as micro pores. EDS mapping analysis confirmed that each gold alloy was 14K with the intended composition; Ni and Cu was included as coloring metals in the white and red gold alloys, respectively. The effective diffusion coefficient was estimated based on EDS line scanning. Individual values of Ni and Cu were $5.0{\times}10^{-8}cm^2/s$ and $8.9{\times}10^{-8}cm^2/s$, respectively. These values were as large as those of the melting points due to the accelerated diffusion in this customized diffusion bonder. Vickers hardness results showed that the hardness values of white gold and red gold were 127.83 and 103.04, respectively, due to solid solution strengthening. In addition, the value at the interface indicated no formation of intermetallic compound around the bonding interface. From the shear strength test, the sample was found not to be destroyed at up to 100,000 gf due to the high bonding strength. Therefore, these results confirm the successful diffusion bonding of 14K white-red golds with a diffusion bonder at a low temperature of $780^{\circ}C$ and a short processing time of 180 seconds.