• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.339-340
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• 2007

Gradient system에 spiral waveform 입력을 가하면 Hardware limitation에 의하여 만들어지는 gradient fields에 Transient time delay가 발생한다. 이를 보상하기 위하여, Gradient system을 R-L-C 회로로 모델링하여 재구성에 필요한 k-space trajectory를 보정하여 개선된 image를 획득하였다.

• Investigative Magnetic Resonance Imaging
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• v.13 no.1
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• pp.15-21
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• 2009

Purpose : A method to estimate a real k-space trajectory based on a circuit model of the gradient system is proposed for spiral imaging. The estimated k-space trajectory instead of the ideal trajectory is used in the reconstruction to improve the image quality in the spiral imaging. Materials and Methods : Since the gradient system has self resistance, capacitance, and inductance, as well as the mutual inductance between the magnet and the gradient coils, the generated gradient fields have delays and transient responses compared to the input waveform to the gradient system. The real gradient fields and their trajectory in k-space play an important role in the reconstruction. In this paper, the gradient system is modeled with R-L-C circuits, and real gradient fields are estimated from the input to the model. An experimental method to determine the model parameters (R, L, C values) is also suggested from the quality of the reconstructed image. Results : The gradient fields are estimated from the circuit model of the gradient system at 1.5 Tesla MRI system. The spiral trajectory obtained by the integration of the estimated gradient fields is used for the reconstruction. From experiments, the reconstructed images using the estimated trajectory show improved uniformity, reduced overshoots near the edges, and enhanced resolutions compared to those using the ideal trajectory without model. Conclusion : The gradient system was successfully modeled by the R-L-C circuits. Much improved reconstruction was achieved in the spiral imaging using the trajectory estimated by the proposed model.

• KSBB Journal
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• v.15 no.3
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• pp.219-225
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• 2000

Both the production of high spore concentration and high insecticidal activity are required in the production of Bacillus thuringiensis to be used for the bacterial insecticide. In the production of high cell and spore concentrations of B. thuringiensis the continuous fed-batch culture(CFBC) and intermittent fed-batch culture(IFBC) were investigated at $28^{\circ}C$ by maintaining 40% dissolved oxygen concentration. When the final glucose concentration was 50 g/L the maximum viable cell number obtained using the CFBC with linear gradient feeding was $9.37{\times}109$ cells/mL and maximum spore concentration was $8.33{\times}109$ spores/mL which was approximately 84.4% yield of spore formation. When the final glucose concentration was 100 g/L the aximum viable cell and spore concentrations obtained using the IFBC with pH-statb were $1.38{\times}$1010 cells/mL and $1.35{\times}1010$ spores/mL respectively and the yield of spore formation was approximately 97.8%.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.7
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• pp.1303-1313
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• 2001

This study was performed to develop a mobile functional pattern reflecting the characteristics of the middle aged women's lower body types based on the slacks construction components. The results and procedures obtained from this study were as follows; 1. The bodys measurement of the 252 middle aged women of 45∼59 years old were used to analyze the size and somato type. 2. For multiple analysis of the lower body types, horizontal and vertical section maps were obtained by sliding gauge method and extracted constructional factors of slacks. 3. The following condition was determined with both standing and moving position of body: (gradient of C.B.L/2)+3°and (back crotch extention)+2cm. 4. Development of new slacks pattern drafting was based on the result of data analysis. Trough the wearing test by the sensory evaluation, It showed that developed slacks pattern was judged better than existing patterns in items of comfort of comfort of silhouette and moving.

• Weed & Turfgrass Science
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• v.6 no.1
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• pp.61-66
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• 2017

The appropriate level of irrigation for turfgrasses is vital to the performance of the turfgrass as well as conservation of water. Linear gradient irrigation system (LGIS) facilitates long-term study of turf performance under continuous irrigation gradients at extreme ends of the irrigation scale. The objectives of this study were to: a) determine the minimum irrigation requirements and relative drought resistance in three warm season turfgrasses; and b) evaluate the medium to long-term effects of irrigation levels on turf persistence, weed invasion, and susceptibility to diseases. Results suggest that grasses differed in drought resistance and persistence under variable irrigation regimes. Irrigation (Ep) required for consistent acceptable turf quality for respective grasses was Cynodon dactylon x C. transvaalensis (61%), Zoysia matrella L. Merr (73%), and Stenotaphrum secundatum 'Palmetto' (86%). Brown patch infection was most prevalent in Stenotaphrum secundatum 'Palmetto' at 12 and 125% Ep irrigation. Cynodon dactylon x C. transvaalensis and Zoysia matrella L. Merr were better able to adapt to the various irrigation regimes, and this ability allowed these species to resist drought, and maintain turf coverage which in turn, kept weeds and the occurrence of diseases at bay. Ranking these grasses for their drought tolerance abilities showed that Cynodon dactylon x C. transvaalensis had the most outstanding resistance against drought, followed by Zoysia matrella L. Merr, and lastly, Stenotaphrum secundatum 'Palmetto'. Despite having the highest irrigation requirement, Stenotaphrum secundatum 'Palmetto' was still not able to maintain persistence at high irrigation regimes. Likewise, this grass also lost turf coverage at low irrigation levels.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.57-61
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• 2021

Saikosaponin derivatives such as saikosaponins A, B1, B2, B3, B4, C, and D present in Bupleurum falcatum were analyzed by a high performance liquid chromatograph equipped with an evaporative light scattering detector, using different extraction solvents (water and 70% ethanol). The samples were injected into a YMC Pack Pro C18 column and separated using a gradient elution system with a mobile phase composed of acetonitrile and water at a flow rate of 1.1 mL/min. The content of saikosaponin derivatives was higher in 70% ethanol extract than in water extract. This study provides an efficient analytical method for determining the optimal conditions for extraction of saikosaponin derivatives, which can be used as a basis for development of functional foods and pharmaceutical products from B. falcatum.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.359-368
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• 2008

Black soybean has been widely utilized as foods and oriental medicinal materials. The pigmentation in the seed coat of black soybean is due to accumulate anthocyanins in the epidermis palisade layer. The anthocyanins of black soybean seed coat are considered as a parameter of quality evaluation of black soybean. Therefore, the purpose of this study was to investigate the most suitable HPLC condition for simultaneous determination of anthocyanins in black soybean seed coats extracts. The efficient HPLC analytical condition of D3G, C3G, and Pt3G contained extracts of black soybean seed coats was developed. The gradient elution employed a $250\;mm\;{\times}\;4.6\;mm$ i.d. YMC-pak ODS-AM 303 column. The gradient system was used two mobile phases. A gradient elution was performed with mobile phase A, consisting of 5% aqueous formic acid, and mobile phase B, comprising 5% formic acid - acetonitrile, and delivered at a flow rate of 0.7 mL/min as follows: $0{\sim}35\;min$, $90%\;A{\sim}60%\;A$; 36 min, 90% A; 46 min, 90% A. The UV-VIS. detection wavelength was set at 520 nm. The limit of detection (LOD) for D3G, C3G, and Pt3G were under 10 ng/mL.

• Journal of the Korean Mathematical Society
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• v.39 no.5
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• pp.783-800
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• 2002

Let B denote the unit ball in $C^n$, and ν the normalized Lebesgue measure on B. For $\alpha$ > -1, define $dv_\alpha$(z) ＝ $c_\alpha$$(1-\midz\mid^2)^{\alpha}$dν(z), z $\in$ B. Here $c_\alpha$ is a positive constant such that $v_\alpha$(B) ＝ 1. Let H(B) denote the space of all holomorphic functions in B. For $p\geq1$, define the Bergman-Privalov space $(AN)^{p}(v_\alpha)$ by $(AN)^{p}(v_\alpha)$ = ${f\inH(B)$ : $\int_B{log(1+\midf\mid)}^pdv_\alpha\;<\;\infty}$ In this paper we prove that a function $f\inH(B)$ is in $(AN)^{p}$$(v_\alpha)$ if and only if $(1+\midf\mid)^{-2}{log(1+\midf\mid)}^{p-2}\mid\nablaf\mid^2\;\epsilon\;L^1(v_\alpha)$ in the case 1＜p＜$\infty$, or $(1+\midf\mid)^{-2}\midf\mid^{-1}\mid{\nabla}f\mid^2\;\epsilon\;L^1(v_\alpha)$ in the case p ＝ 1, where $nabla$f is the gradient of f with respect to the Bergman metric on B. This is an analogous result to the characterization of the Hardy spaces by M. Stoll [18] and that of the Bergman spaces by C. Ouyang-W. Yang-R. Zhao [13].

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.204-205
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• 2003

Nano 결정립 N $d_2$F $e_{l4}$B+F $e_3$B 복합상 자성 리본은 Extractive melt spinner의 wheel speed를 달리하여 제조하였다. 초기 조성은 N $d_4$F $e_{77.5}$ $B_{18.5}$이고, 이후 제조한 자성 리본의 자기특성은 VSM 및 AGM(Alternating gradient magnetometer)으로 측정하였다. wheel speed 1500rpm, $650^{\circ}C$에서 10분간 열처리한 자성 리본에서 $B_{r}$ = 11.73 kG, $_{i}$ $H_{c}$ = 3.082 kOe, (BH)$_{max}$ = 12.28 MGOe의 자기특성이 나타났다. 이러한 자기특성 원인 규명을 위해 $\delta$M plot과 뫼스바우어 분광학을 사용하였다. $\delta$M plot을 통해 exchange coupling은 초미세립 복합상의 잔류자속밀도에 큰 영향을 미치는 것으로 판단된다. 또한, 뫼스바우어 분광학을 통해 경자성상(N $d_2$F $e_{l4}$B)과 연자성상 F $e_3$B의 부피분율비가 7:3 정도일 때 가장 최적의 자기특성을 발현하였다. 이 경우에 초미세립 복합상의 상호작용력이 가장 크게 발현하는 것으로 판단된다.단된다..된다..된다..

• Food Science and Biotechnology
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• v.18 no.4
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• pp.1035-1037
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• 2009

In this study we analyzed the dynamic changes in microbiota composition during kochujang fermentation at $30^{\circ}C$. During fermentation, the viable cell counts slowly increased and reached $3.2{\times}10^7$ for aerobic bacteria, $8.3{\times}10^3$ for yeast, and $1.4{\times}10^3$ CFU/mL for fungi after 60 days. Bacilli were found to be the most dominant microorganisms throughout the fermentation process. Using the culture dependent method Bacillus subtilis, Bacillus licheniformis, and Bacillus amyloquefaciens were found to be the main species during the early stages of fermentation; however, Bacillus pumilus and Bacillus stearothermophilus became the most dominant species during the late stage of fermentation. In contrast, when the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method was used Bacillus ehimensis was found to be the dominant species during the early stage of fermentation and Bacillus megaterium, B. pumilus, B. subtilis, and B. licheniformis were dominant in the ate stages. These results indicate various other Bacillus species rather than just B. subtilis and B. licheniformis might be involved in the fermentation of kochujang.