• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.259-265
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• 2004

A quicker method was developed for foliar analysis in diagnosis of nitrogen in apple trees based on multivariate calibration procedure using partial least squares regression (PLSR) and principal component regression (PCR) to establish the relationship between reflectance spectra in the near infrared region and nitrogen content of fresh- and dry-leaf. Several spectral pre-processing methods such as smoothing, mean normalization, multiplicative scatter correction (MSC) and derivatives were used to improve the robustness and performance of the calibration models. Norris first derivative with a seven point segment and a gap of six points on MSC gave the best result of partial least squares-1 PLS-1) model for dry-leaf samples with root mean square error of prediction (RMSEP) equal to $0.699g\;kg^{-1}$, and that the Savitzky-Golay first derivate with a seven point convolution and a quadratic polynomial on MSC gave the best results of PLS-1 model for fresh-samples with RMSEP of $1.202g\;kg^{-1}$. The best PCR model was obtained with Savitzky-Golay first derivative using a seven point convolution and a quadratic polynomial on mean normalization for dry leaf samples with RMSEP of $0.553g\;kg^{-1}$, and obtained with the Savitzky-Golay first derivate using a seven point convolution and a quadratic polynomial for fresh samples with RMSEP of $1.047g\;kg^{-1}$. The results indicate that nitrogen can be determined by the near infrared reflectance (NIR) technology for fresh- and dry-leaf of apple.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.663-667
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• 2001

A new secondary metabolite was isolated from the culture broth and mycelium of Streptomyces sp. collected from marine sediment. The structure of this compound was determined to be N-formylantimycic acid methyl ester, an acyclic derivative of antimycin, on the basis of combined chemical and spectral methods. The structure-activity relationship of antimycins is discussed.

• Journal of the Korean Chemical Society
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• v.56 no.1
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• pp.54-57
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• 2012

New Schiff base derivatives of organoheterobimetallic-${\mu}$-oxoisopropoxide $[Bu_2SnO_2Ti_2(OPr^i)_6]$ have been synthesized by the thermal condensation ${\mu}$-oxoisopropoxide compound with Schiff bases in different molar ratios (1:1-1:4) yielded the compounds of the type $[Bu_2SnO_2Ti_2(OPr^i)_{6-n}(SB)_n]$ (where n is 1-4 and SB=Schiff base anion) respectively. The ${\mu}$-oxoisopropoxide derivatives have been characterized by elemental, spectral analysis (IR, $^1H$, $^{13}C$, $^{119}Sn$ NMR) and molecular weight measurement The studies reveal that the derivative compounds show monomeric nature. Further these are found less susceptible to hydrolysis as compared to parent compound and may prove excellent precursors for the mixed metal oxides.

• Journal of the Korean Chemical Society
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• v.58 no.5
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• pp.450-455
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• 2014

In the present study, a series of novel N-(1H-benzo[d]imidazol-2-yl)methyl-5-[(hetero)aryl-1,3,4-oxadiazol-2-yl]methanamine (4a-4j) were efficiently synthesized. Condensation of hydrazide derivative 3 with various carboxylic acid derivatives yielded N-[(1H-benzo[d]imidazol-2-yl)methy](5-substituted-1,3,4-oxadiazol-2-yl)methanamine (4a-4j) and compound 5-{[(1H-benzo[d]imidazol-2-yl)methylamino]methyl}-1,3,4-oxadiazole-2-thiol (4k) was obtained on treating hydrazide 3 with carbon disulfide. All the newly synthesized analogues were characterized by IR, $^1H$ NMR, $^{13}C$ NMR and mass spectral data.

• The Journal of the Acoustical Society of Korea
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• v.17 no.3E
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• pp.3-11
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• 1998

Zero-crossings with Peak amplitudes (ZCPA) model motivated by human auditory periphery was proposed to extract reliable features form speech signals even in noisy environments for robust speech recognition. In this paper, the performance of the ZCPA model is further improved by incorporating conventional speech processing techniques into the model output. Spectral and cepstral representations of the ZCPA model output are compared, and the incorporation of dynamic features with several different lengths of time-derivative window are evaluated. Also, comparative evaluations with other front-ends in real-world noisy environments are performed, and result in the superiority of the ZCPA model.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1628-1628
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• 2001

Near infrared (NIR) spectroscopy is a powerful technique for non-destructive analysis that can be obtained in a wide range of environments. Recently, NIR measurements have been utilized as probe for quantitative analysis in agricultural, industrial, and medical sciences. In addition, it is also possible to make practical application on NIR for molecular structural analysis. In this work, Fourier transform near infrared (FT-NIR) measurements were carried out to utilize extensively in the relative amounts of different secondary structures were employed, such as Iysozyme, concanavalin A, silk fibroin and so on. Several broad NIR bands due to the protein absorption were observed between 4000 and $5000\;^{-1}$. In order to obtain more structural information from these featureless bands, second derivative and Fourier-self-deconvolution procedures were performed. Significant band separation was observed near the feature at $4610\;^{-1}$ ,. Particularly the peak intensity at $4525\;^{-1}$ shows a characteristic change with thermal denaturation of fibroin. The structural information can be also obtained by mid-IR and CD spectral. Correlation of NIR spectra with protein structure is discussed.

• Microbiology and Biotechnology Letters
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• v.25 no.6
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• pp.586-591
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• 1997

In the course of screening for the tipA promoter-inducing substances, we isolated an active compound, sulfomycin Ia, from the mycelium of a microorganism designated 50634. The producing organism was identified as Streptomyces sp. on the basis of taxonomic studies. Sulfomycin Ia was purified from mycelial extract by silica gel column chromatography, LH-20 column chromatography, silica gel TLC, and preparative HPLC. The molecular weight of sulfomycin Ia was determined to be m/z 1129 (M+Na)$^{+}$ by FAB mass measurement and $^{1}$H NMR spectroscopic analysis. The structure was assigned as a derivative of sulfomycin I with thiazole, methyloxazole, oxazole, and pyridine rings by $^{1}$H NMR spectral data.

• Journal of Biosystems Engineering
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• v.24 no.3
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• pp.259-266
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• 1999

This research was carried out to investigate the possibility of real time rice milling ratio measurement using the spectral reflection characteristics. In this study, various methods were compared such as \circled1 using the whiteness meter, \circled2 using the colorimeter, \circled3 using the Visible and the NIR reflection spectrum. The samples were milled in the domain of 84~96% by 0.5% interval classified by milling ratio. The NMG treatment method required about 20 minutes to determine the milled ratio and r2 was 0.0028 to 0.7959 that was very low. In case of whiteness meter, r2 was high but speed of measurement was 5 minutes that was very low. Measurement with the colorimeter required about 5 minutes and r2 was 0.60 to 0.85 that was low. The reflection spectrum were measured in the range of 400~2,500nm with 2nm interval and the MLR model with six-wavelength obtained from first derivative of spectra gave the best results(r2 = 0.967, SEP = 0.729%)

• Environmental Analysis Health and Toxicology
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• v.15 no.1_2
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• pp.39-43
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• 2000

Linear alkyl sulfonates (LAS) constitute a large fraction of the surfactants used in cleaning processes in households, trade and industry Despite the industrial significance and the possible environmental impact of these compounds, the fast and inexpensive determination of LAS concentrations is still a difficult task. In this study, near infrared (NIR) spectroscopy which is a rapid spectroscopic analysis method compared with a traditional analytical method for the measurement of LAS concentration such as HPLC, GC and standard wet chemistry method. NIR spectra of LAS between 0.313 and 25.0% (w/v) in water were utilized to develop a calibration model. The best results (R ＝ 0.998, SEP ＝ 0.244% (w/v)) obtained by using partial least-squares regression with spectral data treatment and 2nd derivatization were comparable to the results (SEC ＝ 0.186% (w/v), SEP ＝ 0.206% (w/v)) obtained by using multiple linear least-squares regression (MLR). However, models based on derivative spectra have no significant advantage with MLR.

• Korean Journal of Pharmacognosy
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• v.27 no.2
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• pp.111-116
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• 1996

The components were isolated from the root of Astragalus membranaceus and their structures were characterized as 3,4-methylenedioxypyrrolealdehyde, $7-O-{\beta}-D-glucopyranosyl$ 7, 3'-dihydroxy-4'-methoxy isoflavone and a naphthalene derivative on the basis of spectral and physical methods. $7-O-{\beta}-D-glucopyranosyl$ 7, 3'-dihydroxy-4'-methoxy isoflavone and the naphthalene compound showed protective effect on $CC_{l4}-induced$ cytotoxicity in primary cultured rat hepatocytes.