• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2217-2222
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• 2011

In this paper, the relationship of potential and charge distribution in channel for double gate(DG) MOSFET has been derived from Poisson's equation using Gaussian function. The relationship of subthreshold swing and oxide thickness has been investigated according to variables of doping distribution using Gaussian function, i.e. projected range and standard projected deviation, The analytical potential distribution model has been derived from Poisson's equation, and subthreshold swing has been obtained from this model for the change of oxide thickness. The subthreshold swing has been defined as the derivative of gate voltage to drain current and is theoretically minimum of 60 mS/dec, and very important factor in digital application. Those results of this potential model are compared with those of numerical simulation to verify this model. As a result, since potential model presented in this paper is good agreement with numerical model, the relationship of subthreshold swing and oxide thickness have been analyzed according to the shape of doping distribution.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.219-228
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• 2018

Purpose: This study evaluated the feasibility of a near-infrared spectroscopy technique for the rancidity prediction of soybean oil. Methods: A near-infrared spectroscopy technique was used to evaluate the rancidity of soybean oils which were artificially deteriorated. A soybean oil sample was collected, and the acid values were measured using titrimetric analysis. In addition, the transmission spectra of the samples were obtained for whole test periods. The prediction model for the acid value was constructed by using a partial least-squares regression (PLSR) technique and the appropriate spectrum preprocessing methods. Furthermore, optimal wavelength selection methods such as variable importance in projection (VIP) and bootstrap of beta coefficients were applied to select the most appropriate variables from the preprocessed spectra. Results: There were significantly different increases in the acid values from the sixth days onwards during the 14-day test period. In addition, it was observed that the NIR spectra that exhibited intense absorption at 1,195 nm and 1,410 nm could indicate the degradation of soybean oil. The PLSR model developed using the Savitzky-Golay $2^{nd}$ order derivative method for preprocessing exhibited the highest performance in predicting the acid value of soybean oil samples. onclusions: The study helped establish the feasibility of predicting the rancidity of the soybean oil (using its acid value) by means of a NIR spectroscopy together with optimal variable selection methods successfully. The experimental results suggested that the wavelengths of 1,150 nm and 1,450 nm, which were highly correlated with the largest absorption by the second and first overtone of the C-H, O-H stretch vibrational transition, were caused by the deterioration of soybean oil.

• Journal of the Korean Chemical Society
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• v.25 no.1
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• pp.38-43
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• 1981

Pyrrolidone-anilide derivatives from L-glutamic acid and anilines were synthesized as follows: The products were identified by elementary analysis, IR, NMR and Mass spectra with (R)-2-pyrrolidone-5-carbox-anilide, (R)-2-pyrrolidone-5-cabox-p-chloroanilide, (R)-2-pyrrolidone-5-carbox-o-toluidide, (R)-2-pyrrolidone-5-carbox-m-toluidide and (R)-2-pyrrolidone-5-carbox-p-toluidide. The products were testes for their phytotoxicity on the germination and the seedling growth of radish and rice plants. Among them, (R)-2-pyrrolidone-5-carbox-anilide and (R)-2-pyrrolidone-5-carbox-p-chloroanilide derivatives were strongly inhibitory especially on the germination and the seedling growth of radish seeds. All the compounds also showed an inhibitory activity upon the germination of rice seeds. Additionally, the inhibiting rate of radish growth differs according to the isomeric position(ortho, meta and para) of the methyl group; (R)-2-pyrrolidone-5-carbox-m-toluidide derivative was more effective than both (R)-2-pyrrolidone-5-carbox-o-toluidide and (R)-2-pyrrolidone-5-carbox-p-toluidide derivatives.

• Journal of the Korean Chemical Society
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• v.38 no.2
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• pp.151-159
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• 1994

The portable gas chromatography system was developed which was consisted of ambient vapor sampler(AVS), short capillary column(3 m long, 0.32 mm i.d. GC(SCCGC), photoionization detector (PID) and vacuum pump which was operated at subambient pressure. The seletion of capillary column was based on the theoretical calculation from Golay equation. The pressure ratio of column inlet and outlet appropriated between 1.03 and 1.2 in the system. The available column flow were 0.87∼4.63 ml/min at the pressure ratios. The AVS consisted of three concentric tubes and enables rapid, repetitive introduction of vapor samples directly into capillary column and showed good reproducibility. The subambient column outlet pressure with PID resulted in a significant increase in the optimum column flow, permitting rapid analysis. The baseline separation of m-xylene and o-xylene was able to within 40 second with the system. Parameters affecting the column resolving power were sampling duration, column length and diameter, and the pressure ratio. Effects of these parameters were investigated using bezene derivative compounds.

• Proceedings of the Botanical Society of Korea Conference
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• 1999.07a
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• pp.11-15
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• 1999

In order to evlauate feasibility of the gene tagging by the maize transposable element Ac in heterologous plant systems, we have investigated physical distances and directions of transposition of the element in Arabidopsis thaliana and tobacco cultured cell line BY-2. We prepared a T-DNA construct that carried a non-autonomous derivative of Ac with a site for cleavage by endonuclease I-Scel (designated dAc-I-RS element). Another cleavage site was also introduced into the T-DNA region outside dAc-I-RS. A number of transgenic Arabidopsis plants were generated, each of which had a single copy of the T-DNA at a different chromosomal location. To examine the pattern of transposition, three out of these transgenic plants were crossed with the Arabidopsis plant that carried the gene for Ac transposase and progeny in which dAc-I-RS had been transposed were isolated. After digestion of the genomic DNA of these progeny with I-SceI, sizes of segment of DNA were determined byd pulse-field gel electrophoresis. We also performed linkage analysis for the transposed elements and sites of mutations near the elements. Our results with three transgenic lines showed that 50% of all transposition events had occurred within 1,700 kilo-base pairs (kb) on the same chromosome, with 35% within 200 kb, and that the elements transposed in both directions on the chromosome with roughly equal probability. The data thus indicate that the Ac-Ds system is most useful for tagging of genes that are present within 200 kb of the chromosomal site of Ac in Arabidopsis. In addition, determination of the precise localization of the transposed dAc-I-RS element should definitely assist in map-based cloning of genes around insertion sites. In the present paper, we report typical examples of such gene isolation studies.

• Proceedings of the Botanical Society of Korea Conference
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• 1985.08b
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• pp.51-57
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• 1985

In order to evlauate feasibility of the gene tagging by the maize transposable element Ac in heterologous plant systems, we have investigated physical distances and directions of transposition of the element in Arabidopsis thaliana and tobacco cultured cell line BY-2. We prepared a T-DNA construct that carried a non-autonomous derivative of Ac with a site for cleavage by endonuclease I-Scel (designated dAc-I-RS element). Another cleavage site was also introduced into the T-DNA region outside dAc-I-RS. A number of transgenic Arabidopsis plants were generated, each of which had a single copy of the T-DNA at a different chromosomal location. To examine the pattern of transposition, three out of these transgenic plants were crossed with the Arabidopsis plant that carried the gene for Ac transposase and progeny in which dAc-I-RS had been transposed were isolated. After digestion of the genomic DNA of these progeny with I-SceI, sizes of segment of DNA were determined byd pulse-field gel electrophoresis. We also performed linkage analysis for the transposed elements and sites of mutations near the elements. Our results with three transgenic lines showed that 50% of all transposition events had occurred within 1, 700 kilo-base pairs (kb) on the same chromosome, with 35% within 200 kb, and that the elements transposed in both directions on the chromosome with roughly equal probability. The data thus indicate that the Ac-Ds system is most useful for tagging of genes that are present within 200 kb of the chromosomal site of Ac in Arabidopsis. In addition, determination of the precise localization of the transposed dAc-I-RS element should definitely assist in map-based cloning of genes around insertion sites. In the present paper, we report typical examples of such gene isolation studies.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.184-191
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• 1994

A zearalenone derivative, methyldihydroxyzearalenone has been isolated from a plant pathogenic fungus, Drechslera portulacae which causes necrosis on the leaves and stem of Portulaca oleracea. It was characterized as 3, 4, 5, 6, 9, 10-hexahydro-8, 9, 16-trihydroxy-14-methoxy-3-methyl-1H-2-benzoxacyclotetradecine-1, 7(8H)-dione on the basis of spectral analysis. Methyldihydroxyzearalenone treatment at $3{\times}10^{-5}M$ inhibited root length of Echinochloa crus-galli and Abutilon avicennae by 35.7% and 72.6% as compared with the control, respectively.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.513-517
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• 2000

As a precursor of tetrathiafulvalene (TTF) derivative, 5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin-2-thione (compound 3) was synthesized by the unusual Lawesson's reaction. Depending upon the substituents such as dimethyl and diphenyl groups, two different products containing 1,4-dithiin and thiophene moieties, respectively, were obtained and characterized by $^{13}C$ NMR and high-resolution electron impact (HREI) mass spectroscopy. The formation of 3 was further characterized by X-ray structure analysis. Crystallographic data for 3: triclinic, space group P1, a=4.145(2)$\AA$, b=10.600(2)$\AA$, c=12.279(2)$\AA$, $\alpha$=71.440(10)$^{\circ}$, $\beta$=84.30(2)$^{\circ}$, $\gamma$=87.31(2)$^{\circ}$, Z=2 and R(wR$_2$)=0.0559(0.1416). The formation mechanism of two products was suggested and compared each other.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.149-158
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• 2006

A review has been made on what kind of method can be applied to predict the dynamic derivatives of the separated PLF(Payload Fairing) halves of a launch vehicle in consideration of technology and budget. An optimal approach is selected considering the geometric characteristics of the PLF halves, the aerodynamic conditions and the required accuracy. The time history of aerodynamic force/moment coefficients are obtained for the forced harmonic motions by solving the unsteady Euler equations derived with respect to the inertial reference frame. and the dynamic derivatives are deduced by integration of the aerodynamic coefficients for one period. In this research, the dynamic derivatives are presented for 0.6$\leq$ M $\leq$2.0, $-180^{\circ}$ $\leq$$\alpha$ $\leq$$180^{\circ}$ and $-90 ^{\circ}$$\leq$$\beta$$\leq$$90 ^{\circ}$.

• KSBB Journal
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• v.11 no.6
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• pp.712-717
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• 1996

Cellulase was modified with synthetic copolymers of polyoxyethylene derivative and maleic acid anhydride. The saccharification characteristics and enzymatic reaction kinetic mechanism of modified and native cellulases were observed. In modification reaction of cellulase, degree of modification(DM) increased, as mass ratio of copolymers to enzyme increased. Maximum DM was 55% at mass ratio of 4 and remained activity was 75%. In saccharification experiment modified enzyme had maintained higher stability than native enzyme over all the reaction and the final conversion yield of modified enzyme was greater than that of native enzyme. Numerical simulation based on the reaction mechanism considering enzymatic deactivation was performed. Modified enzyme had kept higher free enzyme concentration over all the reaction than that of native enzyme. Comparing calculation values with experimental data, calculation values were in accordance with experimental data.