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        검색결과 70

        41.
        2016.04 구독 인증기관·개인회원 무료
        Chitin synthase (CHS) is an important enzymatic component, which is required for chitin formation in the cuticles and cuticular linings of other tissues in insects. CHSs have been divided into two classes, class A and B, based on their amino acid sequence similarities and functions. Class A CHS (CHS-A) is specifically expressed in the epidermis and related ectodermal cells such as tracheal cells, while expression of class B CHS (CHS-B) is expressed in gut epithelial cells that produce peritrophic matrices. In this study, we cloned the CHS-A gene from the beet armyworm, Spodoptera exigua. The SeCHS-A mRNA was expressed in all developmental stages and specifically in the epidermis and tracheae tissue by RT-PCR analysis. Expression of SeCHS-A gene was suppressed by feeding double-stranded RNA (dsRNASeCHS-A, 150 ng/larva) in the fifth instar of S. exigua. The suppression of SeCHS-A gene expression significantly induced mortality on pupal stage. Also, larvae fed with dsRNASeCHS-A significantly enhanced pathogenicity of an entomopathogenic fungus, Beauveria bassiana ANU1. These results suggest that the SeCHS-A gene plays an important role in development of S. exigua and dsRNA, which is a specific to SeCHS-A gene, may be applied to effective pest control with B. bassiana.
        42.
        2016.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        플라스틱 담도스텐트는 주로 양성 혹은 악성 담도 폐쇄시 종종 사용된다. 그러나 스텐트의 폐색은 스텐트 사용으로 인 해 발생하는 가장 큰 단점으로 이로 인해 스텐트의 개존 기간은 약 3개월이며 교체를 요하게 된다. 담도스텐트를 장기간 거치시 스텐트가 오히려 담석 형성의 병소로 작용할 수 있으며 저자들은 4년간 플라스틱 담도스텐트 거치 후 발생 한 stent-stone complex의 증례를 경험하였다. Stent-stone complex는 기계적 쇄석술과 풍선 도관을 사용하여 효과적으로 제거되었으며 모든 이물이 그러하듯이 스텐트도 장기간 거치시 담석 형성의 새로운 병소로 작용할 수 있다는 것을 고려할 필요가 있겠다.
        4,000원
        43.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyurethane is an elastomer polymer, which is flexible, tough and resistant. This material is widely used various fields such as automobile, aeroplane, textiles, construction industries. Currently there exists more than 1,000 manufacturing companies in Korea that are closely related to Polyurethane. In spite of a number of Polyurethane manufacturing companies, there are little attention in academia as well as industries to study the safety and manufacturing process improvement on Polyurethane. In this paper, we consider a case study for the Polyurethane manufacturer to improve productivity by using safety management and manufacturing process reengineering. After careful analysis, we derive three enhancements to increasing the safety and productivity for the target company. Especially, we achieve about 16% productivity improvement in roller manufacturing process by replacing manual stirring job with automated mixing machine.
        4,300원
        44.
        2013.04 구독 인증기관·개인회원 무료
        We previously reported Pear Pest Forecasting Management System (PPFMS) for the Improvement of pass ratio of Korean exporting pears. It is consisted of regular field forecasting by pear farmers, meteorological data obtained by automatic weather station (AWS), an internet web page (http://pearpest.jnu.ac.kr/) as information collecting and providing ground, and information providing service. Currently, we are expanding this system to the area, Cheonan and Ansung, where pear orchards are organized into exportation-specific group. Further, the information obtained from field forecasting and AWS were up-loaded to under-constructing upgraded webpage (http://www.kpear.kr), with several pest/disease-related information. We hope this pest forecasting management system increases the pass ratio of Korean exporting pears throughout establishment of farmer-oriented forecasting, inspiring farmers’ effort for the prevention and forecasting of diseases and pests occurring at pear orchards.
        45.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The ice tank is important facility to check the performance of the ship and offshore in ice condition before the construction. MOERI(Maritime & Ocean Engineering Research Institute) constructed ice model basin on the end of 2010. The ice technology to know the phenomena of ice near the ship and to estimate power of the ship in model scale is the main characteristic of the ice model basin. To achieve this goal in one ice sheet, making of test plan and feasibility check of test possibility have to review in the beginning stage of the every test. This paper describes the number of maximum resistance and self propulsion test in a sheet of level ice and proposes the methodology to optimize pack ice, rubble ice, brash ice and ice ridge test in MOERI ice tank. The feasibility of free running test to know maneuvering performance in ice field and some specific idea to measuring ice thickness and ice ridge shape was proposed.
        4,000원
        46.
        2011.05 구독 인증기관·개인회원 무료
        The pear psylla, Cacopsylla pyricola Foerster (Homoptera: Psyllidae), is a serious insect pest of commercial pear crops. The species, which resides on pear trees throughout its life cycle, is rapidly spreading in some regions of the world. Given the life cycle, it is unclear how such a rapid spread has been facilitated. Presently, the population genetic structure of the species including genetic diversity and gene flow was studied to understand the nature of dispersal and field ecology of the species. Pear psylla was collected from several pear orchards in Korea. The 658-bp region of mitochondrial COI gene and the 716-bp long complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA were sequenced. Unlikely other previously studied insect pests, the COI-based genetic diversity of the pear psylla was extremely low (maximum sequence divergence of 0.15%). This finding allowed us to conclude that the species may have been introduced in Korea relatively recently, possibly with the phenomenon of genetic bottlenecks. ITS2 sequence-based analyses of phylogeny, population differentiation, gene flow, and hierarchical population structure all concordantly suggested that the pear psylla populations in Korea are neither genetically isolated nor hampered for gene flow. These genetic data are concordant with the dispersal of an overwintering winterform morph outside the non-pear habitat in the fall and the possibility of subsequently longer distant dispersal.
        47.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The measurement of ice properties such as thickness, strength are important to know the performance of the ice breaking vessel. The measuring equipment of ice properties and methods are summarized in this paper. The actual measured data are also described. The strength of ice at Svalbard area on April 2010 is much stronger than the Chukchi Sea on August 2010. The mean strength of Svalbard is about 500 kPa and one of Chukchi Sea is 250 kPa. The first sea trial in Arctic sea using Araon was carried out in the Chukchi Sea. The power and speed was also measured to check the ship performance in ice. The speed was measured from GPS(Global Positioning System) and engine power was recorded from DPS(Dynamic Positioning system) of Araon. The design target of Araon in level ice is 3 knots in 1m thickness and 630 kPa flexible strength but mean speed in Chuckchi sea is 3.98 knots when 6.6 MW engine power, 2.4m ice thickness and 250 kPa strength. This results comes from the difference of ice types and the weak flexible strength of ice but it will be a good information to know the performance of Araon in similar ice condition.
        4,000원
        52.
        2020.09 KCI 등재 서비스 종료(열람 제한)
        본 연구의 목적은 선상에서 열수광물 내 Au를 효과적으로 용출하기 위한 마이크로웨이브-차아염소 산 용출의 적용 가능성을 파악하는 것이다. 비교용출실험은 마이크로웨이브 질산용출의 유(T1)/무(T2)에 따른 Au 용출율의 영향을 확인하였다. 또한, 기계적 교반에 의한 전통적인 용출(T3)과 마이크로웨이브 용출에 따른 Au 용출율을 비교하였다. 마이크로웨이브 질산용출결과(고액비; 10%, 용출온도; 90oC, 용출시간; 20분), 금속의 용출율은 As>Pb>Cu>Fe>Zn 순으로 높게 나타났으며, 용출잔사 내 Au의 함량은 33.77 g/ton에서 60.02 g/ ton으로 증가하였다. 염화물 용매제를 이용한 비교용출실험 결과, Au의 용출율은 T1(61.10%)>T3(53.30%) >T2(17.30%)순으로 높게 나타났다. 따라서, 해수를 이용하여 제조 가능하고 용출과정에서 발생되는 염소 가스를 포집하여 재이용 가능한 염화물은 Au용출을 위한 최적의 용매제로 예상된다. 또한 마이크로웨이브를 적용함으로써 시간, 효율 및 에너지 측면에서 효과적일 것으로 판단되어진다.
        53.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        본 연구는 금 정광에 함유된 비소(As) 및 비스무스(Bi)와 같은 페널티 원소(penalty elements)를 제거하기 위한 목적으로 마이크로웨이브-질산침출을 이용하였다. 또한, 금 정광 시료로부터 금 함량을 증가시키고자 하였다. 침출조건은 페널티 원소의 제거를 향상시키기 위해 질산농도, 침출시간 그리고 고액비를 변화하였다. 실험결과 고체-잔류물에서 시료무게 감소율, 비소와 비스무스의 제거율 그리고 금 함량은 질산농도와 침출시간이 증가할수록 그리고 고액비가 감소할수록 증가하였다. 최대 비소와 비스무스 제거율 및 금 함량이 얻어지는 침출조건은 질산용액의 농도 6 M, 침출시간 5분이었다. 이 때, 고체-잔류물 시료의 무게 감소는 87 %, 비소 제거율은 98.23 %, 비스무스는 거의 제거(100 %)되었고 금 함량은 81.36 g/t에서 487.32 g/t으로 증가하였다. 고체-잔류물을 XRD로 분석한 결과, 질산농도가 증가할수록 황철석 피크들은 사라지고 반면에, 원소 황의 피크들이 증가하였다.
        54.
        2017.09 KCI 등재 서비스 종료(열람 제한)
        Platycodon grandiflorum (Bell flower) is an important plant that has traditionally been used as herbal medicine for the treatment of cough, phlegm, sore throats, lung abscesses, chest pains, dysuria, and dysentery. The present study was initiated to investigate the feasibility of inducing shoot and root organogenesis in cultured explants of P. grandiflorum in a range of culture media and through use of various plant growth regulators (PGRs). The plantlets (Stem containing one node) were isolated and cultured on different concentrations of Murashige and Skoog (MS) medium supplemented with PGRs. We found that proliferation and elongation of shoots and roots could be achieved on ¼ MS for P. grandiflorum with wild and green petals and on ⅛ MS for P. grandiflorum with double petals. The highest levels of development and elongation of adventitious shoots and roots were observed when petal explants were cultured on ¼ MS (pH 3.8) supplemented with 5% sucrose. Increasing the agar concentration reduced shoot growth and rooting potential; nevertheless, the highest number of shoots and roots was observed on 0.6% agar. In the case of growth regulators, ¼ MS supplemented with 1 mg L-1 6-benzylaminopurine (BA) was found to be best for shooting, although higher concentrations of BA tended to reduce shoot and root elongation. The highest number of shoots was achieved on 0.5 mg ․ L-1 thidiazuron (TDZ) from double petal explants grown on ⅛ MS. However, root and shoot elongation were found to decrease when TDZ concentrations were increased. Low concentrations of kinetin, naphthalene acetic acid, indole acetic acid, and 3-indole butyric acid induced shoot and root proliferation and elongation. Taken together, our study showed that low concentrations of PGRs induced the greatest root formation and elongation, showing that the optimal concentration of PGRs for shoot proliferation was species-dependent.
        55.
        2016.09 KCI 등재 서비스 종료(열람 제한)
        The optimum concentrations of clove oil as an anesthetic for olive flounder (Paralichthys olivaceus) and the stress response of the fish to clove oil anesthesia were determined over a range of water temperatures, and investigated in a simulated transport experiment using analysis of various water and physiological parameters. While the time for induction of anesthesia decreased significantly as both the concentration of clove oil and water temperature increased, the recovery time increased significantly (P<0.05). The plasma cortisol concentration in fish at each temperature increased significantly up to 12 h following exposure (P<0.05), then decreased to 48 h (P<0.05). The DO dissolved oxygen concentrations, pH values, and the fish respiratory frequencies decreased over 6 h following exposure to clove oil in all experimental groups (P<0.05), whereas the NH4 + and CO2concentrations in all experimental groups increased up to 6 h (P<0.05). The pH values and DO concentrations increased with increasing clove oil concentration (P<0.05) in the 6 h following exposure, and the CO2 and NH4 + concentrations and the respiratory frequencies decreased with increasing clove oil concentration (P<0.05). The results of this experiment suggest that clove oil reduced the metabolic activity of olive flounder, thus reducing NH4 + excretion and O2 consumption. In conclusion, clove oil appears to be a cost-effective and efficient anesthetic that is safe for use and non-toxic to the fish and users. Its use provides the potential for improved transportation of olive flounder.
        56.
        2015.06 KCI 등재 서비스 종료(열람 제한)
        This study was performed to investigate the growth characteristics and inorganic components of Codonopsis lanceolata regarding regional differences. The plant height of Japanese Codonopsis lanceolata was 373.6 cm, so it’s revealed that it has more vigorous growth than Korean won. The flowering time of Korean Codonopsis lanceolata was 2 weeks faster than Japanese one. Total fresh weight of root was 41.0 g and 39.0 g for Korean and Japanese respectively, thus, no significance difference was found. However, regarding fresh weight, Korean one had a more fresh weight (35.4 g) of main root parts, but Japanese one had a more fresh weight (9.6 g) of the lateral root part. Each inorganic component was found more in the aboveground parts, regardless of the region and the content of K was the largest. Regarding the content of macroelements for each part of Codonopsis lanceolata, the content of Na, Mg, P, S, and Ca in Korean Codonopsis lanceolata was found the highest on the leaf, followed by stem and root. In the case of Japanese Codonopsis lanceolata, same result was found on the content of Mg and Ca, however, the highest content of Na and P was found in the stem.
        57.
        2015.06 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to compare the growth, inorganic components, and proximate components of Codonopsis lanceolata grown in 10 regions of Korea for selecting superior species and breeding by crossing. Among the all tested lines, the shortest plant height (217.12 cm) was observed from the Ulleungdo region line (No. 4) while the longest (273.9 cm) was observed from Hwasun region line (No. 9). In addition, the lines of central and northern region (No. 1~No. 7) tend to have shorter plant height than those of southern region (No. 8~No. 9) except Jejudo region line (No. 10). Flowering tends to be late towards southern region, and lines in central and northern regions were started flowering about 2 weeks earlier than those in southern regions. However, the heaviest root weight was 13.1 g, found in only Jejudo line (No. 10) whereas there was no significant difference found in the other regions which have a range of 8.3~11.0 g. The inorganic components were varied in each line, however, proportion of macroelements, such as K, Ca, and P, was the largest for every line. Especially for Heongseong region line (No. 2), had larger proportion of macroelements than the others. There was a difference of proximate compositions of Codonopsis lanceolata, except the moisture content, among all regions, however, it was generally shown that the content of crude protein (1.31~3.76%) and crude fiber (2.18~3.12%) was the highest.
        58.
        2013.02 KCI 등재 서비스 종료(열람 제한)
        평판 검출기(flat-panel detector)는 필름-스크린 시스템과 비교하여 넓은 범위의 노출지수(dynamic range)를 갖게 된다. 평판 검출기를 대상으로 임상에서 일반적으로 사용하고 있는 Abdomen supine 노출 조건인 81kV에 20mAs를 기준으로 전신형 팬텀 whole body human phantom PBU-50 (Kyoto, kagaku, Japan)을 모의 환자로 화질평가와피폭선량측면에서 비교 연구하였다. PSNR값이 30dB이상으로 판독 가능한 영상의 kV변화에 따른 DAP값은 약 19.6배차이를 나타냈다. 또한 kV변화에 따른 유효선량을 ICRP 103을 기준으로 비교한 결과 방사선에 의한 확률적 영향이 증가함을 알 수 있었다. 방사선검사자의 지속적인 교육 및 지도를 통한 우리나라에 맞는 디지털 방사선 Technical chart를 마련하여 양질의 영상과 환자피폭선량에 대한 기준 선량을 마련해야 할 것이다.
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