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        검색결과 52

        1.
        2022.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Metal-organic frameworks (MOFs) are widely used in various fields because they make it easy to control porous structures according to combinations of metal ions and organic linkers. In addition, ZIF (zeolitic imidazolate framework), a type of MOF, is made up of transition metal ions such as Co2+ or Zn2+ and linkers such as imidazole or imidazole derivatives. ZIF- 67, composed of Co2+ and 2-methyl imidazole, exhibits both chemical stability and catalytic activity. Recently, due to increasing need for energy technology and carbon-neutral policies, catalysis applications have attracted tremendous research attention. Moreover, demand is increasing for material development in the electrocatalytic water splitting and metal-air battery fields; there is also a need for bifunctional catalysts capable of both oxidation/reduction reactions. This review summarizes recent progress of bifunctional catalysts for electrocatalytic water splitting and metal-air batteries using ZIF-67. In particular, the field is classified into areas of thermal decomposition, introduction of heterogeneous elements, and complex formation with carbonbased materials or polyacrylonitrile. This review also focuses on synthetic methods and performance evaluation.
        4,000원
        2.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigate the effect of phosphorous content on the microstructure and magnetic properties of Fe83.2Si5.33-0.33xB10.67-0.67xPxCu0.8 (x = 1–4 at.%) nanocrystalline soft magnetic alloys. The simultaneous addition of Cu and P to nanocrystalline alloys reportedly decreases the nanocrystalline size significantly, to 10–20 nm. In the P-containing nanocrystalline alloy, P atoms are distributed in an amorphous residual matrix, which suppresses grain growth, increases permeability, and decreases coercivity. In this study, nanocrystalline ribbons with a composition of Fe83.2Si5.33-0.33xB10.67- 0.67xPxCu0.8 (x = 1–4 at.%) are fabricated by rapid quenching melt-spinning and thermal annealing. It is demonstrated that the addition of a small amount of P to the alloy improves the glass-forming ability and increases the resistance to undesirable Fex(B,P) crystallization. Among the alloys investigated in this work, an Fe83.2Si5B10P1Cu0.8 nanocrystalline ribbon annealed at 460oC exhibits excellent soft-magnetic properties including low coercivity, low core loss, and high saturation magnetization. The uniform nanocrystallization of the Fe83.2Si5B10P1Cu0.8 alloy is confirmed by high-resolution transmission electron microscopy analysis.
        4,000원
        3.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the expansion of various distribution channels in online and offline stores, TV, and mobile, consumers now have more information search and retail selection channels to choose from than ever before. Major retailers now use multi- and omni-channel strategies. This study focused on cross-channel consumption, which involves the use of different information search and purchase channels. Using crosschannel consumption, consumers can search for information online and then make purchases offline and vice versa. The purpose of this study was to examine the relationship between channel strategies and other consumer variables, and the study also assessed the effect of product type. To conduct this empirical study, the researchers developed a consumer questionnaire concerning three consumer channel strategies-on-on, cross, and off-off-and four product categories-clothing, cosmetics, books, and electronics. The results indicated that gender and marital status did not influence consumer channel strategies, but that age did have a significant influence. The analysis showed that consumers in their 40s preferred the cross channel strategy, perceiving it to be effective, satisfactory, and rewarding. Compared to other products, clothing products showed higher levels of cross channel strategies. Consumers indicated that they prefer searching for information online and then purchasing clothing offline. Overall, clothing products generated higher levels of channel satisfaction and channel switch intentions. Cross-channel clothing shoppers reported effective information retrieval times but longer delivery times.
        4,200원
        4.
        2018.05 구독 인증기관·개인회원 무료
        Chronic problems of water treatment membranes are fouling phenomena and membrane damage during the cleaning process. In this study, to solve these problems, a separation membrane in the form of a hollow fiber having excellent physical properties was produced by using the thermally induced phase separation (TIPS). The material used to make the water treatment membrane is poly(vinylidene fluoride) (PVDF). In the evaluation of the properties of the manufactured hollow fiber, citric acid which is an acidic solution and NaCl which is a basic solution were used and experiments of chemical resistance were proceed. In order to confirm the performance of hollow fiber membrane, water flux and tensile strength were measured.
        5.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is difficult to make an accurate estimate of the economic value and effects on societal economy of Nano-technologies. This research measures an economic value of Nano-technologies quantitatively and analyzes its influences on societal economy. This paper chooses some major industries as analysis targets and adapts the DEFRA comparative methodology model which has been developed in the UK and recommended by OECD. For this reason, some industries which are in range of economic value assessment were investigated and related data were collected. Also, the economic value and societal influences of Nano-technologies were calculated, through the procedure of the model. In addition, this study conducts a questionnaire to experts for the validity of measurement results and procedures. This paper suggests a guideline for economic value and effects on societal economy of Nano-technologies assessments through quantitative Defra comparative methodologies.
        4,300원
        6.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Flexible transparent conducting films (TCFs) were fabricated by dip-coating single-wall carbon nanotubes (SWCNTs) onto a flexible polyethylene terephthalate (PET) film. The amount of coated SWCNTs was controlled simply by dipping number. Because the performance of SWCNT-based TCFs is influenced by both electrical conductance and optical transmittance, we evaluated the film performance by introducing a film property factor using both the number of interconnected SWCNT bundles at intersection points, and the coverage of SWCNTs on the PET substrate, in field emission scanning electron microscopic images. The microscopic film property factor was in an excellent agreement with the macroscopic one determined from electrical conductance and optical transmittance measurements, especially for a small number of dippings. Therefore, the most crucial factor governing the performance of the SWCNT-based TCFs is a SWCNT-network structure with a large number of intersection points for a minimum amount of deposited SWCNTs.
        3,000원
        7.
        1996.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구의 목적은 해마부경화와 연관되어 나타나는 경련성발작의 고 찰에 있어 자기공명영상의 친단적 가치를 평가하기 위해서이다. 자기공명 영상상 해마부경화로 판독된 18 례를 대상으로 하였다. 해마부격화의 자기공명영상 친단은 형태학적 변화와 해마의 선호강또 변화에 기초를 두었고 이러한 자기공명영상진단을 임상겁사상 전형적인 격련성 발작이 있었는지의 여부및 뇌파검사결과와 비교하여 분석하였다. 타 펌스시권스와 비교시 빠른 스핀에코 T2강조영상에서 정상 해마의 선 호강도와 경화된 해마부의 신호강도간에 17 .4%의 가장 큰 증가율을 보였 다. 자기공명영상상 해마부경화로 나타난 18 에중 14 례는 증상과 뇌파검사 결과상 측두엽간절로 나타나는 일치를 보였고 4 례는 다른 결과를 보였다. 따라서 자기공명영상 검사는 해마부겸화의 고찰과 친단에 매우 유용하 다고 생각되며 빠른 스핀에코 T2강조영상은 여러 펼스 스권스중 가장 큰 신호강도의 차이를 보임으로써 해마부경화의 고찰에 있어 매우 민감한 검사방볍이라고 사료된다.
        4,000원
        8.
        2018.10 서비스 종료(열람 제한)
        Background : Korean ginseng require 3 - 4 years to produce mature seeds from their mother plants. Therfore, it takes over 20 years to genetic fixation by artificial crossing of 8 generation. Anther culture is a useful method for obtaining homozygotes in only one generation. However, there is not much research on ginseng yet. In this study, we investigated the callus induction of anther depending on the type and concentration of the plant growth regulators in Panax ginseng C. A. Meyer. Methods and Results : Flower buds of P. ginseng were cold pretreated at 2 days before the anthers were plated on the induction medium. The flower buds were immersed in 70% ethanol for 30 sec min, washed two times with sterile distilled water, surface-sterilized in 2% sodium hypochlorite solution for 20 min, then rinsed five times with sterile distilled water. The anthers were placed on Petri dishes containting fifteen different concentrations and combinations of 2,4-D, NAA, BAP and KT. Callus induction was significantly influenced by the type and combination of plant growth regulators. The highest callus induction rate was observed in GR5 medium at 79.2%. The 2,4-D mediums had significantly higher callus induction than the NAA medium, and 2,4-D 1 ㎎/ℓ have a higher callus induction rate than the other concentrations. The increase of callus induction rate was not observed by the addition of cytokinin, but the callus induction rate was gradually decreased as the BAP concentration was increased. There was no difference in callus induction rate between BAP and KT. Conclusion : The important factor for inducing callus of ginseng anther was the addition of 2,4-D, and no effect of cytokinin addition could be found.
        9.
        2018.10 서비스 종료(열람 제한)
        Background : Mutagenesis is one of the most powerful method for genetic variation, however there is little research history in P. ginseng. The seeds and vegetative tissues are materials commonly used for mutagenesis, but there is a problem that chimeras known as sectoral differences can occur and unintentional poor selection can occur owing to the influence of the growth environment. The combination of in vitro culture and mutagenesis can eliminate the effects of the environmental factors. Methods and Results : Gamma irradiation was carried out using a 60Co irradiator (3000Ci, Nordion Inc., Ottawa, Canada) of the Korea Atomic Energy Research Institute, Jeongeup, Korea. The explants containing the somatic embryos were treated with 20, 40, 60, 80, and 100 Gy. Gamma-rays affected the somatic embryos produced in vitro depending on the dose. The survival rate of somatic embryo was significantly influenced by gamma irradiation. Also, the development of the embryo was changed by gamma irradiation depending on each dose. When somatic embryos were transferred to the medium supplemented with GA3, they started to germinate but were affected significantly by gamma irradiation dose. When germinated shoots were transferred to 1/2 SH medium to induce rooting, as the concentration of gamma ray treatment increased, the rooting gradually decreased. Conclusion : Considering the overall survival rate, germination rate, embryo development, and rooting rate, the optimal dose of gamma rays to be used with somatic embryo is estimated to be between 60 Gy and 80 Gy.
        10.
        2018.10 서비스 종료(열람 제한)
        Background : Panax ginseng C. A. Meyer is an important medicinal herb and their major pharmacologically active components are ginsenosides. Many studies have reported that various ginsenosides are effective in the treatment of human diseases such as cancer, cardiovascular and alzheimer’s disease. However, it is difficult to create new desirable variation such as increased ginsenosides. Since the frequency of spontaneous mutations is rare naturally and difficult to apply to plant breeding, artificial mutation inductions are necessary to obtain noble genetic resources having desirable traits. Methods and Results : Gamma irradiation was carried out using a 60Co irradiator (3000Ci, Nordion Inc., Ottawa, Canada) of the Korea Atomic Energy Research Institute, Jeongeup, Korea. One-year-old ginsengs were treated at 20, 40, 60, 80, and 100 Gy. The emergence rate was significantly decreased with increasing gamma doses. When irradiated at more than 80 Gy, it did not emerge at all. Survival rate was also significantly influenced by gamma-ray dose. The maximum survival rate were recorded in control. The survival rate of 20 Gy was 22.0% and only 1.0% survived when 40 Gy dose was treated. There was no survival when irradiated at more than 60 Gy. Gamma irradiation also affected the phenotype of emerged plants. The growth of plants derived from irradiated one-year-old ginsengs was decreased and the leaves became variegated or curled. Also, rusty roots resulting from physiological disorders were observed and the rhizomes, which is a kind of dormant bud, were destroyed completely. Conclusion : Based on these results, we estimated the optimal dose for mutation induction by gamma-ray treatment of one-year-old ginseng is to be less than 20 Gy.
        11.
        2018.10 서비스 종료(열람 제한)
        Background : The conventional ginseng breeding is time-consuming and labor-intensive. Furthermore, it is difficult to create new desirable variation such as resistant to various stresses and increased ginsenosides. Therefore, creating variants remains a serious challenge of ginseng breeding. Methods and Results : Gamma irradiation was carried out using a 60Co irradiator (3000Ci, Nordion Inc., Ottawa, Canada) of the Korea Atomic Energy Research Institute, Jeongeup, Korea. The dehiscent seeds were treated 20, 40, 60, 80, 100, 120, 150, 200 and 400 Gy. The seed germination was greatly influenced by gamma-ray treatment. It was found that the germination rate decreased significantly when treated at 60 Gy or more. The maximum survival rate was achieved at 20 Gy but there was no significant difference from control. Following exposure to 40 Gy or more, survival rate was declined compared to the control. Gamma irradiation affected not only the germination and survival rate but also the growth of plants germinated from seeds. As gamma irradiation dose increased, the size of the plant decreased sharply and it also had a negative effect on root development. Conclusion : Considering the extent of reduction in the germination and survival rates, as well as growth reduction, the optimal dose of gamma-ray for inducing mutation in ginseng dehiscent seeds was estimated at approximately 40 Gy, because the germination rate observed at 40 Gy was similar to that of the observed in the control, while the survival rate was 50% of the control.
        12.
        2018.10 서비스 종료(열람 제한)
        Background : Recently, the shortage of first planted ginseng field has increased direct seeding cultivation in paddy. Therefore, the demand for the development of ginseng varieties suitable for direct seeding cultivation in paddy has increased. So the aim of this study was selection ginseng varieties and germplasms suitable for direct seeding cultivation in paddy. Methods and Results : We used 13 varieties and 191 lines of Korean ginseng (Panax ginseng C. A. Meyer) in this study. Ginseng Seeds were harvested at the end of July 2013, sown in mid-November, and were grown for four years in paddy. In 2017, the survey was conducted on 27 items of growth characteristics in accordance with the standards for survey of ginseng variety, and the degree of diseases and physiological disorders. Among ginseng varieties, the growth of Gopoong, Sunwon and Gwumjin were excellent. However, the incidence of physiological disorder was low in Gumpoong and Geumsun. Among the genetic sources, the growth of 7 ginseng lines, such as G04092, G04098, M05015, G07053, G10069 and G10093, were excellent. However, the incidence of physiological disorder was low in 10 lines of ginseng, such as G04020, G04061, G04081, G04092, G05054, G07052, G07053, G10069 and G10093. Conclusion : This result suggests that 5 varieties and 10 lines of ginseng showed outstanding growths in paddy. In the future, we will review the characteristics of root and the content of ginsenosides of ginseng variety and elite lines.
        13.
        2018.10 서비스 종료(열람 제한)
        Background : One generation of ginseng is four years, so it takes a long time to breed. So far, a total of 18 ginseng varieties have been developed under pure line selection. However the pure line selection can reach the limit, because ginseng’s gene pool is very small. A solution to this is the need for cross breeding. Therefore, this study carries out cross breeding for the introduction of excellent character and expansion of variation and check the F1 generation. Methods and Results : As plant materials, Chunpoong, Yunpoong, Gumpoong, Chungsun and Cheonryang were used in this study. In order to cultivate the F1 of ginseng, we cross-bred ginseng varieties from mid-May to late May 2013 and harvested seeds from late July. Ginseng seeds were sown on November 15 and cultivated in 2014 for one year in the field and then transplanted into the main field in 2015. In 2017, the survey was conducted on 27 items of growth characteristics in accordance with the standards for survey of ginseng variety, such as length of leaf, length of stem and width leaf, and the degree of diseases and physiological disorders. In a combination of cross-breeding in domestic ginseng varieties, the germination time and growth characteristics of F1 were not much different from the parent plants, but the incidence of disease was reduced. Conclusion : According to this study, there was a tendency for expressing dominant figures in the crossbreeding between ginseng varieties. In the future, we will review the characteristics of root and the content of ginsenosides of F1.
        14.
        2018.10 서비스 종료(열람 제한)
        Background : Recently, there is an urgent demand for development of new varieties with enhanced resistance to various biotic/abiotic stresses. One generation of ginseng is four years, so it takes a long time to breed. To increase the efficiency of the ginseng breeding and save time and effort, it is necessary to build a ginseng core collection. This study examined the major growth characteristics of genetic sources for the establishment of core collection. Methods and Results : As plant materials, 187 ginseng lines collected in 2003 were used in this study. Ginseng Seeds were harvested at the end of July 2014, sown in mid-November, and cultivated in 2015 for one year in the field and then transplanted into the main field in 2016. All phenotypes including agronomic characteristics, seed yield, and physiological response to biotic/abiotic stresses were investigated according to the ginseng GAP and UPOV guidelines. The stem colors of the collected ginseng germplasm were classified as the five classes; light green, green, light purple, purple and dark purple, but most of them were purple or dark purple. The locations of distribution of anthocyanin coloration in stem were classified into the four classes; proximal end, proximal end and petiole part, the entire stem and the stem with purple not revealed, but most of them were petiole part or the entire stem. The shapes of leaflet were classified the four classes; the long elliptic, elliptic, slender type, and spatulate type. Most of surveyed lines were elliptic type. When the leaflet of ginseng was laterally cut, the shape was classified into the three types; concave type, plane type and convex type. Most of surveyed lines were red berry color. Conclusion : The genetic pool of ginseng is known to be narrow. The results of this study showed similar characteristics among the ginseng fields collected. In the future, we will carry out the survey about quantitative characteristics and correlations of ginseng genetic resources for establishment of Korean ginseng core collection.
        15.
        2018.05 서비스 종료(열람 제한)
        Background : Endophytes are generally regarded as beneficial microorganisms that live in plant tissues without disease symptoms. The endophytic species may differ depending on the plant age, the sampled time, the plant genotype, and the tissue. Although numerous endophytes have been identified from various plants, little is known about the endophytic bacteria of Panax quinquefolius, a useful herb plant. Therefore, the aim of this study is to investigate diversity and distribution of endophytic bacteria from 2-years-old to 6-years-old P. quinquefolius and to evaluate antimicrobial activity of isolates. Methods and Results : Initially, 2-years-old to 6-years-old plants were collected and sterilized with 70% ethanol and sodium hypochlorite, subsequently we prepared individual suspensions which were mixed with sample and sterile distilled water. A total of 88 single colonies were obtained from the LB agar plates spreading suspension. Using 16S rDNA sequencing, the taxonomic status of the isolates were determined consequently 42 species were identified. The 42 species were classified into 4 phylum; Proteobacteria (64%), Firmicute (27%), Actinobacteria (8%), and Bacteroidetes (1%). Based on age, the isolates of 5-years-old plant showed highest diversity. Moreover, Actinomycetales, Bacillales, and Pseudomonadales were equally dispersed as predominant orders in 5-years-old plant. The antagonistic activities of isolates against a phytopathogen, Pseudomonas syringae pv. tomato DC3000 : GFP (Pst : GFP) were performed using dual culture assays. We measured antibacterial activity by quantifying fluorescence of Pst:GFP which representing pathogen growth. As a result, 36 isolates inhibited growth of Pst:GFP. Interestingly, all species belonging Pseudomonas in this study showed strong antibacterial activity against Pst : GFP. Conclusion : These results improve our understanding of the structure and diversity of the endophytic bacteria of P. quinquefolius. Furthermore, we suggest that bacterial endophytes with antimicrobial activity might have useful as materials for biocontrol agents.
        16.
        2018.05 서비스 종료(열람 제한)
        Background : Recently, there is a urgent demand for development of new varieties with enhanced resistance to various biotic/abiotic stresses. In order to develop ginseng varieties with such traits, systematic breeding program and comprehensive field studies are prerequisite. Methods and Results : ‘Jinwon' seeds were collected in 2003 from the farmer field of Pocheon. Physiological investigation and propagation were conducted from 2008 to 2010. It was given the name 'Eumseong No. 11 through the observed yield trial from 2011 to 2013 and local adaptability was carried out from 2014 to 2017. All phenotypes including agronomic characteristics, seed yield, and physiological response to biotic/abiotic stresses were investigated according to the ginseng GAP and UPOV guidelines. Red leaf and red berry at maturing stage were observed. The time of emergence, flowering and berry maturity of the ‘Jinwon’ were faster than those of ‘Chunpoong’. Stem length of ‘Jinwon’ was longer than that of ‘Chunpoong’, whereas stem diameter was thicker than that of ‘Chunpoong’. Main root length was similar but main root diameter is thicker than that of ‘Chunpoong’. The yield performance of this variety was 576 ㎏/10 a in local adaptability test for two years, which is 9% higher than that of ‘Chunpoong’. ‘Jinwon’ showed strong resistance at high temperatures. Conclusion : Our study demonstrated that ‘Jinwon’ is an ideal variety with heavier root weight and enhanced stress resistance and contribute will enhance biotic/abiotic stress resistance and increase the farmers' income.
        17.
        2017.12 서비스 종료(열람 제한)
        The management of acute Achilles tendon rupture has been well established and is often treated with interrupted tenorrhaphy. While surgical site infection, rerupture and ankle contracture has been reported as potential complications, the tendon often heals uneventfully, and reports of complication other than mentioned above are extremely rare. We report a case of a common peroneal nerve injury which occurred after Achilles tendon repair surgery. The injury may have occurred following compartment syndrome from the anteriorly place long leg splint. To our knowledge, this is the first report in the literature.
        19.
        2017.05 서비스 종료(열람 제한)
        Background : This study aimed to investigate the effect of elevated temperature by climate change on growth and ginsenoside contents of Korean ginseng, which requires low temperature during growth period. Methods and Results : Yunpoong was transplanted in temperature gradient chamber (TGC) for high temperature treatment and then growth characteristics and ginsenoside contents were investigated by growth period. Stem length, petiole length, leaf length and leaf width were increased as the temperature was higher than Ambient Temperature (Amb), but stalk diameter was decreased and small petiole length, number of petiole and leaf were no significant difference. Root growth, whereas, including length diameter and weight were decreased as the temperature was higher than Amb. Compared with Amb, root length, diameter and weight were decreased by 19.6%, 22.4% and 41.5% at Amb+6, respectively. The higher the temperatures are associated with the more ginsenoside contents. Compared to Amb, total ginsenoside contents were increased by 68% and 78% at Amb+4℃ and Amb+6℃, respectively. Almost all contents of individual ginsenoside, with the exception of Rg1, made a significant difference. Conclusion : When temperatures rises during growth period, the growth of ginseng was decreased but, ginsenoside contents were increased.
        20.
        2016.10 서비스 종료(열람 제한)
        Background : Ginseng (Panax ginseng C. A. Meyer) is a precious herb plant belonging to Araliaceae family especially in Asia and it has been cultivated more than a thousand years as a traditional medicine. Due to their pharmacological efficacy, old ginseng plants are traded high price, however, there are no crucial criteria to determine the ginseng age. To prevent illegal transactions, we assessed the telomere of ginseng roots based on modifications of the assays reported previously. Methods and Results : It is known that telomere length of ginseng root is shorter upon organismal aging. In this study, to support the determination of ginseng age, we modified and investigated methods through telomere analysis. Firstly, we examined the southern blot analysis whether telomere length depends on ginseng age. Based on previous study, we measured telomerase activity that is correlate with age. Furthermore, telomeric DNA was quantified by fluorescence in situ hybridization (FISH) to corroborate telomere shortening. The older ginseng root was shown short telomere length to compare with younger ginseng roots. Also enzyme activity of telomerase and amount of telomeric DNA represented decrease patterns upon age. Conclusion : Taken together, it is help to determine the age of ginseng through various methods using telomere because the results shown to positive correlation between telomeric characteristics and age for ginseng.
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