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        검색결과 24

        1.
        2023.11 구독 인증기관·개인회원 무료
        Raman characteristics of various minerals constituting natural rocks collected from uranium deposits in Okcheon metamorphic zone in Korea are presented. Micro-Raman spectra were measured using a confocal Raman microscope (Renishaw in Via Basis). The focal length of the spectrometer was 250 mm, and a 1800 lines/mm grating was installed. The outlet of the spectrometer was equipped with a CCD (1,024256 pixel) operating at -70°C. Three objective lenses were installed, and each magnification was 10, 50, and 100 times. The diameter of the laser beam passing through the objective lens and incident on the sample surface was approximately 2 m. The laser beam power at 532 nm was 1.6 mW on the sample surface. Raman signal scattered backward from the sample surface was transmitted to the spectrometer through the same objective lens. To accurately determine the Raman peak position of the sample, a Raman peak at 520.5 cm-1 measured on a silicon wafer was used as a reference position. Since quartz, calcite, and muscovite minerals are widely distributed throughout the rock, it is easy to observe with an optical microscope, so there is no difficulty in measuring the Raman spectrum. However, it is difficult to identify the uraninite scattered in micrometer sizes only with a Raman microscope. In this case, the location of uraninite was first confirmed using SEM-EDS, and then the sample was transferred to the Raman microscope to measure the Raman spectrum. In particular, a qualitative analysis of the oxidation and lattice conditions of natural uraninite was attempted by comparing the Raman properties of a micrometer-sized natural uraninite and a laboratory-synthesized UO2 pellet. Significantly different T2g/2LO Raman intensity ratio was observed in the two samples, which indicates that there are defects in the lattice structure of natural uraninite. In addition, no uranyl mineral phases were observed due to the deterioration of natural uraninite. This result suggests that the uranium deposit is maintained in a reduced state. Rutile is also scattered in micrometer-sizes, similar to uraninite. The Raman spectrum of rutile is similar in shape to that of uraninite, making them confused. The Raman spectral differences between these two minerals were compared in detail.
        2.
        2022.05 구독 인증기관·개인회원 무료
        FTIR (Fourier Transform Infrared) and Raman spectra of KJ-II bentonite provided by Clariant Korea were compared with those of MX-80 bentonite. The FTIR spectra were obtained using a Nicolet 5 FTIR spectrometer (Fisher Scientific) equipped with a diamond ATR (Attenuated Total Reflection) module. The spectra were collected for 64 scans with a resolution of 4 cm−1. Raman spectra were obtained using an optical microscope (Olympus, BX43) and a spectrometer (Andor, SR- 500). The laser beam was focused using an objective lens with a magnifying power of 50. The backscattered light from the sample was collected into an optical fiber with a core diameter of 0.4 mm. The Raman signals were recorded with CCDs (Andor, DV401A-BV for 532 nm laser wavelength and DV420A-OE for 638 and 785 nm laser wavelengths). Each pixel of CCD received the signal for 1 s and its 1000 times accumulated data were collected. The FTIR spectra of the two bentonite samples are very similar. The FTIR spectra of both bentonites showed absorption bands at 3623, 3399, 3231 cm−1 in the higher wavenumber region and at 1637, 1443, 1117, 997, 914, 887, 847, 797, 611, 515, 414 cm−1 in the lower wavenumber region. A sharp band at 3623 cm−1 and the strong band at 997 cm−1 correspond to the OH stretching of structural hydroxyl groups and the Si-O stretching vibration, respectively. In addition to these clear bands, several absorption bands observed in this experiment are well matched with the results reported in various literatures. Unlike the FTIR spectrum, it is not easy to observe the Raman bands of bentonite. The reason is that strong fluorescence interferes with the Raman spectrum. The two bentonite samples showed different fluorescence intensities. In the case of MX-80 bentonite, no clear Raman band was observed due to the influence of very strong fluorescence. KJ-II bentonite showed a relatively weak fluorescence intensity and Raman bands were partially visible at around 147, 260, 397, 709, and 1279 cm−1. In particular, the band at 1279 cm−1 is wide and sturdy. It was observed that the non-powder samples showed a better quality spectra. The Raman characteristics of KJ-II bentonite, which depend on the incident laser wavelength and the sample pretreatment, are discussed in detail.
        3.
        2022.05 구독 인증기관·개인회원 무료
        A deep geological disposal system, which consists of the engineered and natural barrier components, is the most proven and widely adopted concept for a permanent disposal of the high level radioactive waste (HLW) thus far. The clay-based engineered barrier is designed to not only absorb mechanical stress caused by the geological activities, but also prevent inflow of groundwater to canister and outflow of radionuclides by providing abundant sorption sites. The principal mineralogical constituent of the clay material is montmorillonite, which is a 2:1 phyllosilicate having two tetrahedral sheets of SiO2 sandwiching an octahedral sheet of Al2O3. The stacking of SiO2 and Al2O3 sheets form the layered structures, and ion-exchange and water uptake reactions occur in the interlayer space. In order to reliably assess the radionuclide retention capacity of engineered barrier under wide geochemical conditions relevant to the geological disposal environments, sorption mechanisms between montmorillonite and radionuclides should be explicitly investigated in advance. Thus far, sorption behavior of mineral adsorbents with radionuclides has been quantified by the sorption-desorption distribution coefficient (Kd), which is simply defined as the ratio of radionuclide concentration in the solid phase to that in the equilibrium solution; the Kd value is conditional, and there have been scientific efforts to develop geochemically robust bases for parameterizing the sorption phenomena more reliably. In this framework, application of thermodynamic sorption model (TSM), which is theoretically based on the concept of widely accepted equilibrium models for aquatic chemistry, offers the potential to improve confidence in demonstration of radionuclide sorption reactions on the mineral adsorbents. Specifically, it is generally regarded in the TSM that coordination of radionuclides on montmorillonite takes place at the surficial aluminol and silanol groups while their ion-exchange reactions occur in the interlayer space also. The effects of electrical charge on the surface reactions are additionally corrected in accordance with the numerous theories of electrochemical interface. The present work provides an overview of the current status of application of TSM for quantifying sorption behaviors of radionuclides on montmorillonite and experimental results for physical separation and characterization of Ca-montmorillonite from the newly adopted reference bentonite (Bentonil- WRK) by means of XRD, BET, FTIR, CEC measurement, and acid-base titration. The determined mineralogical and chemical properties of the montmorillonite obtained will be used as input parameters for further sorption studies of radionuclides with the Bentonil-WRK montmorillonite.
        10.
        2018.05 서비스 종료(열람 제한)
        Background : The interest in paddy-converted fields to be used as an alternative new farming area for the stable ginseng production is increasing, and made up -32% of the total ginseng cultivation area in Korea in 2014. Therefore, this study examined how soil types and fertilizer regimes influence fatty acid (FA) and vitamin E (Vit-E) variation in 6-years-old ginseng root. Methods and Results : Ginseng variety “Jagyeongjong” was cultivated upland and paddy-converted field, and three organic fertilizers were applied to both fields, at 0, 1, 2, and 4 tons per 1,000 ㎡, prior to the ginseng seedling transplantation. The 37 FAs and 8 Vit-E were analyzed with GC-FID. We observed significant variation in both FA and Vit-E contents owing to the type and quantity of organic fertilizer used in each soil type during cultivation. Unsaturated FAs were approximately 2.7-fold higher in ginseng than in saturated FAs. Linoleic, palmitic, and oleic acids were the most abundant FAs detected in ginseng roots. Additionally, α-tocopherol was the major Vit-E detected. In particular, the increased application of rice straw compost or food waste fertilizer elevated the quantity of nutritionally desirable FAs and bioactive Vit-E in ginseng root. Partial least square-discriminant analysis (PLS-DA) score plots showed that soil type might be the main cause of differences in FA and Vit-E levels in ginseng. Specifically, the PLS-DA model indicated that palmitic acid is a suitable FA marker in determining whether ginseng plants were grown in a paddy-converted field or an upland field. Moreover, linoleic acid levels were highly correlated with α-linolenic acid (r = 0.8374) according to Pearson's correlations and hierarchical clustering analysis. Conclusion : This study investigated how soil type, as well as organic fertilizer type and amount, altered the FA and Vit-E profiles in ginseng roots. Therefore, these preliminary data should be beneficial to ginseng farmers and any industries involved in the production of high quality and nutritional ginseng products.
        11.
        2018.05 서비스 종료(열람 제한)
        Background : Agaricus bisporus mushroom, which originated from Europe, is an edible mushroom with a unique taste and flavor and is the most widely cultivated mushroom type worldwide, particularly because of the relatively high protein, dietary fiber, and vitamin D contents of the fruit body, which have human health benefits like anticancer and DNA damage protection. However, to our knowledge, few studies have been conducted on the ability to discriminate mushroom’s bioactive compounds according to regional production sites. Thus, this study was aimed to examine the regional difference of selected bioactive compounds in of Agaricus bisporus mushroom. Methods and Results : The cultivars (cv.) “Saedo” and “Saehan” obtained from five regions of Korea were measured their phenolics and fatty acids profiling by LC/MS and GC-FID system, respectively. Among 54 targeted phenolics, protocatechuic, p-hydroxybenzoic, caffeic, 2,4-dihydrobenzoic, p-coumaric, and salicylic acids were found in the cv. Saedo and cv. Saehan fruit body. Also, tyrosine and phenylalanine, which are precursor metabolites of phemolics, were also observed in the A. bisporus fruit body. In particular, phenylalanine and p-hydroxybenzoic acid were the most abundant phenolic precusor and metabolite present in the A. bisporus, and was significant with the production regions (p < 0.05). The FA content was significant with the production region, but not much differed (p < 0.05). The n-6 FA including linoleic acid was the major FA in the mushroom, accounting > 70% over total FA content. However, the n-3 FA was the n-6 FA was very minor FA metabolites. Conclusion : These preliminary results can extend knowledge of regional difference of certain targeted bioactive compounds in A. bisporus mushroom produced in Korea, contributing to reliable regional difference with potential broader applications for the international mushroom market.
        12.
        2016.10 서비스 종료(열람 제한)
        Background : study of long yam and short yam (Dioscorea. opposita) are cultivated in temperate regions but tropical yam (Dioscorea alata) are mainly grown in Africa and sub-tropical regions cultivated crops. Recent tropical yam cultivation area of Korea increased but lack the proper cultivation techniques to climate warming. This study was conducted to elucidate the effect of the timely harvest on Tropical yam at 2015 in Institute of Bioresources Research, GBARES. Methods and Results : Tuber of tropical yam were cut as 40 g, and dust-coating sterilized with lime. Seedlings were grown in heating wire installed seed bed from 11. March to 16. May. Experimental field were fertilized 2,000 kg compost, 34 kg N2, 28 kg P2O5, and 28 kg K2O. All amount of compost and P2O5 treated as basal fertilizer. N2 and K2O treated 14 and 10 kg of basal fertilizer, and 20 and 18 kg of additional fertilizer, respectively. Tillage, covering black PE film with 60×25 cm spacing holes on 120 cm row were conducted. Emergence days from 6. April to 18 May until 28 days to 36 days but 15. June and 9. June were each 19 and 7 days. Dry weigh in early stage due to seedling date, while seedling date according from 6. April to 18. May had no difference. seedling date was not effective on total number of tuber but number of marketable tuber (over 200 g). Marketable tuber number of seedling date according to 20. April was increased 35~132% as 4,028 number per 10 a. And tuber with 20. April was 13~73 g heavier. Tuber yield and marketable tuber yield of seedling date as affected by 20. April were respectively 2,518 and 1,273 kg per 10 a compared to 6. April and from 4. May to 15. June as 1,743~2,457 kg and 484~1,027 kg. Conclusion : Tropical yam is low temperature in the cultivation of Korea but also adverse environmental conditions. Frost is not mature enough off before harvesting. Yam had significant increased marketable tuber (over 200 g) yield due to seedling in mid-April Requires cultivation technology.
        14.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        A new pink gerbera (Gerbera hybrida Hort.) cultivar “Pink Giant” was developed from a cross between “Salina” and “Marita” followed by seedling and line selections at the Flower Breeding Research Institute, Gyeongnam Agricultural Research and Extention Services (ARES) in 1999. Characteristic trials were conducted three times from 2002 to 2004. Newly bred “Pink Giant” have shown pink color (RHS, 65-B), semi-double type, and large flower. It also was in good harmony in ray floret color and flower center color with stable flower shape. The vase life was 19.2 days. The average yield of “Pink Giant” was 45.8 flowers per plant in an year in greenhouse yield trails during 2003 and 2004. This cultivar was registered for a commercialization in 2005. “Pink Giant” would be cultured under greenhouse condition in Korea.
        15.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        A new yellow gerbera (Gerbera hybrida Hort.) cultivar “Gold Eye” was developed from a cross between “Songsongee” and “White Day” followed by seedling and line selections at the Flower Breeding Research Institute, Gyeongnam Agricultural Research and Extention Services (ARES) in 2001. Characteristic trials were conducted three times from 2003 to 2004. Newly bred “Gold Eye” have shown yellow color (RHS, 55-C), semi-double type, and large flower. It also was in good harmony in ray floret color and flower center color with stable flower shape. The vase life was 10.2 days. The average yield of “Gold Eye” was 48.8 flowers per plant in an year in greenhouse yield trails during 2003 and 2004. This cultivar was registered for a commercialization in 2005. “Gold Eye” would be cultured under greenhouse condition in Korea.
        19.
        2004.08 KCI 등재 서비스 종료(열람 제한)
        A new yellow gerbera (Gerbera hybrida Hort.) cultivar 'old Moon' was developed from a cross between 'Rita' and 'Ruby Red' followed by seedling and line selections at the Flower Breeding Research Institute, Gyeongnam Agricultural Research and Extention Ser
        20.
        2004.08 KCI 등재 서비스 종료(열람 제한)
        A new bi-colour gerbera (Gerbera hybrida Hort.) cultivar 'Sunny' was developed from a cross 'Princessa' and 'Tamara' followed by seedling and line selections at the Flower Breeding Research Institute, Gyeongnam Agricultural Research and Extension Services
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