• 제목/요약/키워드: Range of variation

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Crystalline Structure and Cu Diffusion Barrier Property of Ta-Si-N Films (Ta-Si-N박막의 조성에 따른 결정구조 및 구리 확산 방지 특성 연구)

  • Jung, Byoung-Hyo;Lee, Won-Jong
    • Korean Journal of Materials Research
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    • v.21 no.2
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    • pp.95-99
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    • 2011
  • The microstructure and Cu diffusion barrier property of Ta-Si-N films for various Si and N compositions were studied. Ta-Si-N films of a wide range of compositions (Si: 0~30 at.%, N: 0~55 at.%) were deposited by DC magnetron reactive sputtering of Ta and Si targets. Deposition rates of Ta and Si films as a function of DC target current density for various $N_2/(Ar+N_2)$ flow rate ratios were investigated. The composition of Ta-Si-N films was examined by wavelength dispersive spectroscopy (WDS). The variation of the microstructure of Ta-Si-N films with Si and N composition was examined by X-ray diffraction (XRD). The degree of crystallinity of Ta-Si-N films decreased with increasing Si and N composition. The Cu diffusion barrier property of Ta-Si-N films with more than sixty compositions was investigated. The Cu(100 nm)/Ta-Si-N(30 nm)/Si structure was used to investigate the Cu diffusion barrier property of Ta-Si-N films. The microstructure of all Cu/Ta-Si-N/Si structures after heat treatment for 1 hour at various temperatures was examined by XRD. A contour map that shows the diffusion barrier failure temperature for Cu as a function of Si and N composition was completed. At Si compositions ranging from 0 to 15 at.%, the Cu diffusion barrier property was best when the composition ratio of Ta + Si and N was almost identical.

HPLC Analysis of Saponins in Platycodi Radix (HPLC를 이용한 길경(桔梗) 사포닌 분석법(分析法))

  • Kim, Hyun-Ki;Choi, Jae-Seok;Yoo, Dae-Seok;Choi, Yeon-Hee;Yon, Gyu-Hwan;Hong, Kyung-Sik;Lee, Byung-Hoi;Kim, Hye-Jin;Kim, Eun-Ju;Park, Byoung-Keun;Jeong, Young-Chul;Kim, Young-Sup;Ryu, Shi-Yong
    • Korean Journal of Pharmacognosy
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    • v.38 no.2 s.149
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    • pp.192-196
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    • 2007
  • A rapid and practical HPLC assay was developed for quantitative analysis of saponins in Platycodi Radix. Seven saponin components in Platycodi Radix, i.e., deapioplatycoside E, platycoside E, deapioplatycodin D$_3$, platycodin D$_3$, polygalacin D$_2$, platycodin D$_2$ and platycodin D were successfully resolved on C18 column and detected by ELSD. Standard curves were linear over the concentration range 1 ${\sim}$2,000 ${\mu}$g/ml (r$^2$>0.992). Intra- and inter-day coefficients for variation of seven saponin components were < 10% and limit of quantification of them were around 0.7${\sim}$1.5 ${\mu}$g/ml, respectively. Using this method, contents of seven saponins in various plant materials under different cultivating conditions were estimated.

Taxonomic Characterization, Evaluation of Toxigenicity, and Saccharification Capability of Aspergillus Section Flavi Isolates from Korean Traditional Wheat-Based Fermentation Starter Nuruk

  • Bal, Jyotiranjan;Yun, Suk-Hyun;Chun, Jeesun;Kim, Beom-Tae;Kim, Dae-Hyuk
    • Mycobiology
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    • v.44 no.3
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    • pp.155-161
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    • 2016
  • The most economically important species used in a wide range of fermentation industries throughout Asia belong to Aspergillus section Flavi, which are morphologically and phylogenetically indistinguishable, with a few being toxigenic and therefore a major concern. They are frequently isolated from Korean fermentation starters, such as nuruk and meju. The growing popularity of traditional Korean alcoholic beverages has led to a demand for their quality enhancement, therefore requiring selection of efficient non-toxigenic strains to assist effective fermentation. This study was performed to classify the most efficient strains of Aspergillus section Flavi isolated from various types of traditional wheat nuruk, based on a polyphasic approach involving molecular and biochemical evaluation. A total of 69 strains were isolated based on colony morphology and identified as Aspergillus oryzae/flavus based on internal transcribed spacer and calmodulin gene sequencing. Interestingly, none were toxigenic based on PCR amplification of intergenic regions of the aflatoxin cluster genes norB-cypA and the absence of aflatoxin in the culture supernatants by thin-layer chromatography analysis. Saccharification capability of the isolates, assessed through ${\alpha}-amylase$ and glucoamylase activities, revealed that two isolates, TNA24 and TNA15, showed the highest levels of activity. Although the degrees of variation in ${\alpha}-amylase$ and glucoamylase activities among the isolates were higher, there were only slight differences in acid protease activity among the isolates with two, TNA28 and TNA36, showing the highest activities. Furthermore, statistical analyses showed that ${\alpha}-amylase$ activity was positively correlated with glucoamylase activity (p < 0.001), and therefore screening for either was sufficient to predict the saccharifying capacity of the Aspergillus strain.

Sensitivity Analysis on Rockfill Material Parameters Influencing Crest Displacement of Concrete-Faced Rockfill Dam (콘크리트 표면차수벽형 석괴댐 정상부 변위에 영향을 미치는 입력물성에 대한 민감도분석)

  • Ha, Ik-Soo;Seo, Min-Woo;Shin, Dong-Hoon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.846-853
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    • 2006
  • In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam with this input parameter. The rockfill material properties for parametric study were obtained from the results of large scale triaxial tests on 34 rockfill materials in the 22 different sites. From the statistical analysis on these data, some statistical characteristics of rockfill material properties such as property range, distribution characteristics, and correlation between the properties were investigated. based on these characteristics, 27 property combinations were constituted by Latin Hypercube sampling method. Dam crest displacements after construction, impounding, and earthquake loading were evaluated by static and dynamic numerical analysis on each combination. From the sensitivity analysis, it was found that the crest displacement of CFR type dam was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the settlement and horizontal displacement of dam crest logarithmically decreased as the shear modulus increased and the difference between the maximum value and the minimum vale amounted to about 9.5 times in case of settlement and about 10 times in case of horizontal displacement.

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Studies on Dose Distribution and Treatment Technique of High Energy Electron (고(高)에너지 전자선(電子線) 치료(治療)를 위(爲)한 선량분포(線量分布) 및 기술적(技術的) 문제(問題)의 연구(硏究))

  • Lee, D.H.;Chu, S.S.
    • Journal of Radiation Protection and Research
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    • v.3 no.1
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    • pp.6-22
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    • 1978
  • High energy electron beams took effect for tumor radio-therapy, however, had a lot of problems in clinical application because of various conversion factors and complication of physical reactions. Therefor, we had experimentally studied the important properties of high energy electron beams from the linear accelerator, LMR-13, installed in Yonsei Cancer Center. The results of experimental studies on the problems in the 8, 10, 12 Mev electron beam therapy were reported as following. 1. On the measurements of the outputs and absorbed doses, the ionization type dosimeters that had calibrated by $^{90}Sr$ standard source were suitable as under 3% errors for high energy electrons to measure, but measuring doses in small field sizes and the regions of rapid fall off dose with ionization chambers were difficult. 2. The electron energy were measured precisely with energy spectrometer consisted of magnet analyzer and tele-control detector and the practical electron energy was calculated under 5% errors by maximum range of high energy electron beam in the water. 3. The correcting factors of perturbated dose distributions owing to radiation field, energy and material of the treatment cone were checked and described systematically and variation of dose distributions due to inhomogeneous tissues and sloping skin surfaces were completely compensated. 4. The electron beams, using the scatterers; ie., gold, tin, copper, lead, aluminium foils, were adequately diffused and minimizing the bremsstrahlung X-ray induced by the electron energy, irradiation field size and material of scatterers, respectively. 5. Inproving of the dose distribution from the methods of pendulum, slit, grid and focusing irradiations, the therapeutic capacity with limited electron energy could be extended.

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Application of Synthetic Mineral Microparticles with Various Metal Species

  • Lee, Sa-Yong;Hubbe, Martin A.
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.40 no.5
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    • pp.1-10
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    • 2008
  • Synthetic mineral microparticles (SMM) is a patented system which has been developed to promote drainage of water and retention of fine particles during papermaking. It is shown in patents that the SMM system can have advantages in both of drainage and retention, compared with montmorillonite (bentonite), which is one of the most popular materials presently used in this kind of application. Turbidity and gravity drainage time were measured using a Britt-Jar test with representative SMM formulations, in order to confirm the efficacy of SMM covering a wide range of compositions and discover effects of some key variables that have the potential to lead to unexpected advantages in terms of the effectiveness of the microparticles, when used in combination with a cationic polyacrylamide treatment of papermaking furnish. An iron silicate showed highest retention performance, as well as suitably fast drainage time relative to other metal silicate and bentonite. Zinc silicate improved retention and drainage. SMM synthesized from aluminum sulfate ($Al_2(SO_4){_3}$) did not show a benefit in retention and drainage, relative to bentonite. SMM synthesized from aluminum chloride ($AlCl_3$) performed better in drainage and retention than bentonite when the Al/Si ratios were 0.76 and 1.00. It was found that when the Al/Si ratio and neutralization are considered, pH variation due to the change of Al/Si ratio can be a key factor to control the size of primary metal silicate particles and the degree of coagulation of the primary particles.

Preparation and Characterization of Nano-sized Hydrogels (nanogels) Using Inverse-miniemulsion Polymerization Method for Protein Drug Delivery (단백질 약물 전달을 위한 Inverse-miniemulsion Polymerization 방법으로 제조하는 나노크기의 수화젤(나노젤)의 제조 및 특성평가)

  • Kang, Soo-Yong;Munkhjargal, Odonchimeg;Kim, Seong-Cheol;Park, Ah-Reum;Shim, Young-Key;Lee, Woo-Kyoung
    • Journal of Pharmaceutical Investigation
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    • v.40 no.2
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    • pp.73-78
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    • 2010
  • Hydrogels are thought to be a promising delivery carrier for protein drugs because of their favorable aqueous environment compared with nano/micro-particles of hydrophobic polymer such as PLGA. In this study, nano-sized hydrogels (nanogels) were fabricated using inverse-miniemulsion polymerization method. The mean size of nanogels in range of 90-160nm and affected by the preparation parameters such as sonication time and concentration of monomer. While longer sonication time and lower concentration of acrylamide monomer showed a tendency to produce smaller nanogels and to have lower lysozyme activity, variation of bis-methylene acrylamide concentration made no difference. Although both longer soncaton time and lower acrylamide concentration increased in vitro release rate, acrylamide concentration was more effectively affected to the control of protein release rate, which indicated that the release rate of protein from nanogels affected by not only their size but also internal structure. In conclusion, nanogels prepared by inverse-miniemulsion can be a useful carrier for application of protein drug, because of simple process, minimum contact of organic solvent and high protein activity.

The Clinical Study of the Ferguson's Angle, Lumbar Lordotic Angle, Lumbar IVD Angle of Low Bcak Pain Patients Induced in Traffic Accident (교통사고로 유발된 요통 환자의 요천각, 전만각 및 IVD각에 대한 임상적 고찰)

  • Lee, Gil-Jae;Park, Kyung-Moo;Lim, Je-Yeon;Song, Yun-Kyung;Lim, Hyung-Ho
    • Journal of Korean Medicine Rehabilitation
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    • v.19 no.2
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    • pp.227-239
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    • 2009
  • Objectives : The purpose of this study is to investigate the relation of Ferguson's angle, Lumbar lordotic angle, Lumbar IVD angle in traffic accident patients. Methods : Total patients were classified into TA(traffic accident) inpatients and non-TA(lumbago) inpatients. We analyzed the characteristics of each group Ferguson's angle, Lumbar lordotic angle, L4-5 IVD angle, L5-S1 IVD angle on X-ray film. Results : 1. Ferguson's angle and Lumbar lordotic angle were smaller than normal range. Non-TA group's angles were smaller than TA group's angles. 2. L4-5 IVD angle of female showed smaller than that of male in TA groups. The older age was, the smaller L4-5 IVD angle was at non-TA groups. 3. L5-S1 IVD angle of female showed smaller than that of male in total groups. The older age was, the smaller L5-S1 IVD angle was at non-TA groups. 4. Ferguson's angle, Lumbar lordotic angle, Lumbar IVD angle were related with direct proportion in total groups. 5. Non-TA groups showed more effective VAS variation than TA groups. Conclusions : Lumbar angles were intimately related with each others. And lumbar angles have an effect on curative value.

Temperature-dependent Photoluminescence of Boron-doped ZnO Nanorods

  • Kim, Soaram;Park, Hyunggil;Nam, Giwoong;Yoon, Hyunsik;Kim, Jong Su;Kim, Jin Soo;Son, Jeong-Sik;Lee, Sang-Heon;Leem, Jae-Young
    • Bulletin of the Korean Chemical Society
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    • v.34 no.11
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    • pp.3335-3339
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    • 2013
  • Boron-doped ZnO (BZO) nanorods were grown on quartz substrates using hydrothermal synthesis, and the temperature-dependence of their photoluminescence (PL) was measured in order to investigate the origins of their PL properties. In the UV range, near-band-edge emission (NBE) was observed from 3.1 to 3.4 eV; this was attributed to various transitions including recombination of free excitons and their longitudinal optical (LO) phonon replicas, and donor-acceptor pair (DAP) recombination, depending on the local lattice configuration and the presence of defects. At a temperature of 12 K, the NBE produces seven peaks at 3.386, 3.368, 3.337, 3.296, 3.258, 3.184, and 3.106 eV. These peaks are, respectively, assigned to free excitons (FX), neutral-donor bound excitons ($D^{\circ}X$), and the first LO phonon replicas of $D^{\circ}X$, DAP, DAP-1LO, DAP-2LO, and DAP-3LO. The peak position of the FX and DAP were also fitted to Varshni's empirical formula for the variation in the band gap energy with temperature. The activation energy of FX was about ~70 meV, while that of DAP was about ~38 meV. We also discuss the low temperature PL near 2.251 eV, related to structural defects.

Effects of Nonequilibrium Condensation on an Oblique Shock Wave in a Supersonic Nozzle of Constant Expansion Rate (팽창률이 일정한 초음속 노즐흐름에 있어서 비평형 응축이 경사충격파에 미치는 영향)

  • 강창수;권순범;김병지;홍종우
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1311-1319
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    • 1990
  • For the purpose of preventing the flow undulation in the cascade of steam turbine, the blades are made into a constant expansion rate in static pressure. And the flow in those cascades is transonic or supersonic in the range of 0.7-2.0 in Mach number. As a consequence, an oblique shock wave, known as inner or outer edge shock wave, arises in the flow of cascades. Especially when the steam in cascades is in a state of high wetness, nonequilibrium condensation and condensation shock wave occur, and they give rise to an interference with oblique shock wave. In the present study the case of expansion of moist air through a supersonic nozzle of constant expansion rate, which behaves similar to that of wet steam, was adopted. The effect of nonequilibrium condensation on the oblique shock wave generated by placing the wedge into the supersonic part of the nozzle was investigated. Furthermore, the relationship between nonequilibrium condensation zone and incident point of the oblique shock wave, oblique shock wave angle, the variations of angles of incident and reflected shock waves due to the variation of initial stagnation supersaturation and the relationship between the height of Mach stem and initial stagnation supersaturation are discussed.