• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권5호
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• pp.213-218
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• 2003

We investigated the monolayer behavior at the air-water interface with metal solution, the surface morphologies and the electrical properties such as conductivity, The calculated conductivity values of pure water subphase and its complexes with L $i^{+}$ ions are 5.6$\times$10$^{-l6}$ and 1.9$\times$10$^{-14}$ [S/cm], respectively. And the calculated barrier height D values of pure water subphase and its complexes with Li. ions are 0.70 and 0.66 [eV], respectively. We also attempted to fabricate a crown dendrimer Langmuir-Blodgett (LB) films containing functional end group that could form a complex structure with metal ions. Also, we investigated the surface activity of dendrimer films at air-water interface. In AFM images. the larger domains irregularly shaped structures on the top while the smaller ones were free from such defects. In conclusion, it is demonstrated that the metal ion around dendrimer and polymer included crown function group can contribute to make formation of network structure among crown function group and result in change of electrical properties.s.s.

• 대한화학회지
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• 제28권3호
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• pp.163-169
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• 1984

칼륨이온이 dibenzo-18-crown-6(DBC)에 의해 $H_2O-CHl_3-H_2O$액체막을 통하여 운반되는 속도를 10가지 칼륨염의 농도를 변화시키면서 $25^{\circ}C$에서 측정하였다. 운반속도는 농도와 음이온의 특성에 크게 의존했으며 농도효과로 부터 피크르산칼륨의 경우에는 이온쌍 형성으로 인하여 1.0 ${\times}10^{-3}$M을 전후하여 각기 다른 양상을 보였다. 이온의 운반과정은 다단계 착물반응 및 확산과정에 의한 것으로 운반 메카니즘을 체계화하기 위해 비균질성 액체막의 각상에서 갖는 화학종의 에너지 장벽모델을 제시하였다. 또한 이를 음이온의 수화자유 에너지와의 관계를 비교함으로써 새로이 7단계 운반과정을 제시하고 그 운반 메카니즘을 고찰하였다.

• 대한치과보철학회지
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• 제15권1호
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• pp.34-42
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• 1977

The author attempted to observed the histological changes of the temporomandibular joints of rabbits by including malocclusion. Thirth-two healthy male rabbits were devided into two groups; control and experimental group. Eight rabbits were kept as control group, while metal crowns were seated on unilateral lower molar teeth of twenty-four rabbits as experimental group. And the interocclusal distance of the incisal edge was kept 1.5mm from the begining to the end of the experimental periods. Rabbits of each group, one of control group and three of the experimental gorup, were killed at the intervals of one day, three days, one week, two weeks, four weeks, six weeks, eight weeks, and twelve weeks after experiment. The temporomandibular joint including condyle head, articular disc and glenoid fossa were excised and decalcified. The decalcified sections were made histologic sections. The results obtained were as follows. 1. The regressive changes of the condylar head were the main reaction in this experiment that consist of decreasing or increasing thickness of the fibrocartilage zone with hyaline degeneration, decreasing of the cellularity of the proliferative zone, and the irregularity of the arrangement of chondrocytes and size of the lacunae of cartilage cells with chondroclasia and osteoclasia in hypertrophic zone. 2. The regressive changes of the condylar surface of the crown seated side were persisted to the end of the experiment. 3. On the non-crown seated side, severe aggressive changes occurred in initial stage, but hyperplastic changes of the condylar surface noted in the middle of the experimental periods. 4. Although aggressive changes occurred in initial stage of experiment on the non-crown seated side, hyperplastic changes of the condylar surface were noted in the middle of the experimental periods, and remodeling appeared at the termination of the experimental periods. 5. The articular disc exhibited pannus formation on both crown seated and non crown seated side from the beginning of the experiment. The pannus persisted throughout the experiment on the crown seated side, but on the non-crown seated side it disappeared from six week group.

• 한국자원식물학회지
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• 제32권1호
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• pp.53-62
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• 2019

본 연구는 우리나라에 자생하고 있는 비비추속 식물 6종(일월비비추, 주걱비비추, 다도해비비추, 좀비비추, 한라비비추, 흑산도비비추)의 정단을 이용하여 대량증식과 품종개발 등을 위한 기내증식체계를 확립하고자 하였다. 정단은 0.5, 1.0, 2.0, 4.0 mg/L BA와 0.1, 0.5, 1.0, 2.0 mg/L TDZ를 0.1 mg/L NAA와 각각 혼용한 조건과 PGRs을 무첨가한 조건(control)의 MS배지에 배양하였다. 배양 8주 후에 embryogenic callus, somatic embryo, crown bud, 그리고 신초와 뿌리의 분화 및 생육, 생체중 등에 대하여 조사하였다. 6종의 비비추 식물 모두에서 control에 비하여 PGRs 처리구의 embryogenic callus와 somatic embryo 형성율, 다신초 분화율이 높았다. 분화된 신초의 개수는 일월비비추는 2.0 mg/L TDZ에서 5.4개, 주걱비비추와 다도해비비추는 1.0 mg/L TDZ에서 각각 3.3개, 5.8개, 좀비비추는 0.5mg/L BA에서 11.1개, 흑산도비비추는 0.5 mg/L TDZ에서 9.8개, 한라비비추는 1.0 mg/L BA, 0.1 mg/L TDZ에서 8.1개로 가장 많았다. Somatic embryo 형성에서는 다도해비비추와 흑산도비비추가 처리한 PGRs에 대해 효과적이었고, 일월비비추, 주걱비비추, 좀비비추, 한라비비추에서는 상대적으로 효과가 적었다. 4종의 자생 비비추(일월비비추, 주걱비비추, 다도해비비추, 흑산도비비추)에서 조사된 crown bud도 control에 비하여 PGRs 처리구에서 더많이 형성되었다. 주걱비비추는 cytokinin의 종류 및 농도와 상관없이 callus와 신초 분화에 큰 효과가 나타나지 않았지만, crown bud의 형성에는 TDZ에서 약간 증가하였다.

• Bulletin of the Korean Chemical Society
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• 제21권7호
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• pp.685-689
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• 2000

The complexation reaction between Pb2+,TI and Cd2+ions and macrocyclic ligands, 18-crown-6 ( 18C6) and dibenzo- 18-crown-6 (DB 18C6), was studied in dimethylsulfoxide (DMSO)-nitromethane (NM) and dimethyl-formamide (DMF)-nitromethane binary system s by square wave polarography (SWP) technique. The stoichiometry and stability of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the Iigand concentration. In most cases, the stability constants of complexes increase with increasing amounts of the nitromethane in mixed binary solvents used in this study. The complexes formed between 18C6 and DB18C6 and these metal cations in all cases had a stoichiometry of 1 : 1. The results obtained show that there is an inverse relationship between the formation constant of complexes and the donor number of solvents based on a Gatmann donocity scale and the stability constants show a high sensitivity to the composition of the mixed solvent systems. A linear behavior was observed for variation of log Kf of I8C6 complexes vs the composition of the mixed solvent systems in NM/DMSO and NM/DMF,but a non-linear behavior was observed in the case of DB 18C6 complexes in these binary systems. In most of the systems investigated, the Pb2+ cation forms a more stable complex with the 18C6 than other two cations and the order of selectivity of this Iigand for cations is: Pb2+ > TI+,Cd2+.

• 식물조직배양학회지
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• 제26권1호
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• pp.31-35
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• 1999

연초 crown gall tumor와 genetic tumor의 형성시 형태적 특성과 조직배양시 식물호르몬에 대한 반응을 조사하였다. Crown gall tumor는 A. tumefaciens C58을 감염시켜 형질전환된 tumor조직으로부터 획득하였으며, genetic tumor는 N. glauca (2n=24)와 N. langsdorffii (2n=18)의 종간교배에 의하여 유기된 잡종식물체에서 자발적으로 발생한 tumor조직으로부터 획득하였다. 형성된 crown gall tumor, genetic tumor및 teratoma shoot의 형태적 특성은 매우 비슷하였으며, 식물조직배양시 식물호르몬이 전혀 첨가되지 않은 기본배지에서 생장이 왕성하였다. Crown gall tumor는 식물호르몬 무첨가배지에서 전형적인 tumor callus가 형성되었으며 teratoma shoot도 형성되었다. 반면에 genetic tumor는 2,4-D 0.5mg/L 첨가된 배지에서 tumor callus가 형성되었으며, 식물호르몬 무첨가배지에서는 많은 teratoma shoot가 형성되어 식물호르몬의 조절에 의해서 phenotype을 거의 비슷하게 할 수 있었다. Genetic tumor는 재분화시 정상적인 식물체보다는 뿌리를 갖지 못하는 teratoma shoots가 형성되는데 외부에서 인위적으로 식물호르몬인 IAA와 GA, 그리고 active carbon을 첨가하여 완전한 식물체를 생산하는 데는 실패하였다. 그러나 간혹 식물호르몬 무첨가배지에서 뿌리를 갖는 정상식물체로 생장하는 shoot가 형성되었는데 이런 식물체에서도 생장하면서 줄기부분에서 다시 genetic tumor가 형성되었으며, 잎절편을 다시 식물호르몬 무첨가배지에 접종할 경우에도 teratoma shoots를 형성하였다.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.291-304
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• 1997

The purposes of this study were to evaluate the changes in root canal configuration with canal instrumentation using different file types and techniques and to investigate most appropriate instrumentation technique in maintaining the original canal configuration with different file types. Fifty curved mesiobuccal or distobuccal canals of extracted human maxillary molar teeth were instrumented using a step-back technique with stainless steel K-files or nickel-titanium K-files, a crown-down pressureless technique with stainless steel K-files or nickel-titanium K-files and nickel-titanium engine-driven files. Radiographs were taken before and after instrumentation using a specially designed device that allowed for the pre-and postinstrumentation canals to be taken with the same X-ray angulation. Magnified X-ray images on a magnifier screen were traced and post instrumentation canal images were compared with the preinstrumentation ones. Changes in canal curvature and the incidence of procedural accidents were analyzed. The results were as follows : Crown-down pressureless technique with nickel-titanium K-files and nickel-titanium engine-driven filing produced no significant changes in canal curvature (p>0.05), while the step-back technique with stainless steel K-files or nickel-titanium K-files (p<0.01) and the crown-down pressureless technique with stainless steel K-files (p<0.05) produced significant changes. With nickel-titanium K-file, crown-down pressureless technique produced significantly less changes in canal curvature than step-back technique (p<0.05), while there was no significant difference between techniques with stainless steel K-files (p>0.05). File types exerted no significant influences in the changes of canal curvature both in the step-back technique and crown-down pressureless technique (0>0.05). Regardless of the file types used, step-back technique produced more procedural accidents such as ledge or elbow formation, apical zipping and apical transportation than the crowndown pressureless technique and nickel-titanium engine-driven filing. Both with stainless steel K-files and with nickel-titanium K-files, the incidence of apical extrusion of canal debris was higher in step-back technique than in crown-down pressureless technique.

• 한국유기농업학회지
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• 제23권3호
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• pp.497-507
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• 2015

내병성 포도 신품종을 육성하기 위해서는 병해 저항성인 유전자원을 선발하는 것이 요구된다. 본 연구에서는 머스카딘포도와 플로리다 교잡종포도를 대상으로 병원균을 상처접종하여 포도나무 줄기혹병에 대한 저항성을 검정하였다. 3종류의 Agrobacterium vitis 균주를 접종한 포도나무는 품종 간에는 혹의 형성에 차이를 나타내었지만, 병원균의 균주 간에는 차이가 나타나지 않았다. 머스카딘포도는 많은 품종이 감수성이었으며, 'Gold Isle'과 'Africa Queen'은 고도의 감수성이었고 'Welder'와 'Jumbo'는 저항성이었다. 플로리다 교잡종포도는 머스카딘포도에 비해 덜 민감하였으며 'Daytona'와 'Stover' 등은 감수성이고, 'Blanc du Bois'는 중도감수성이었다. 본 연구는 머스카딘포도를 대상으로 줄기혹병에 대한 품종저항성을 판별함으로써 아속간 교잡을 통한 줄기혹병 저항성 포도 신품종육성에 중요한 정보를 제공할 것이다.

• Bulletin of the Korean Chemical Society
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• 제11권4호
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• pp.276-281
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• 1990

The equivalent conductance of univalent cation (potassium, silver, thallium and ammonium) perchlorates in methanol containing 18-membered crown ethers, 18-crown-6 (18C6) and 1,10-dithia-18-crown-6 (DT18C6) were measured at different temperatures. The equivalent conductances of ammonium perchlorate were increased by increasing content of DT18C6 exceptionally, due to more favorable solvations than complexations. From the equivalent conductance changes, the formation constants for 1:1 compmlexes have been determined, and the values of enthalpy and entropy changes have been calculated. The complexations of 18C6 and DT18C6 with the univalent cations under investigation are all exothermic and the ${\Delta}$S values are all negative and no considerable differences around 50 J/ (k mol). The selectivity order of 18C6 is $K^+ > Tl^+ > Ag^+ > NH_4^+$, while that of DT18C6 is $Ag^+ > Tl^+ > NH_4^+ > K^+$. By sulfur substitutions in 18C6 result in significant decrease in stability, but the stability of $Ag^+$-DT18C6 complex are $10^4$ times larger than those of $K^+$. This increase of stabilities for $Ag^+$-DT18C6 complex are primary due to the result of favorable exothermic heat of reaction between the polarizable soft cation and soft sulfur centers. In NMR experiment, the stepwise additions of cation perchlorates into crown ether solutions induced two major spectral changes. First, the resonance all shift down field and the cation induced shifts were linear up to 1:1 cation/crown ratio, above which no further changes were observed. On the basis of these results, it could be concluded that 1:1 complex is formed. Second, the magnitudes of cation induced shifts were different each other in same ligand. By addition of silver ion to the solution of DT18C6, the largest shift of proton peak near the sulfur atom was observed. These effects are also arisen from the results of covalent bonding between "soft-soft" interactions.

• 식물병연구
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• 제14권3호
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• pp.159-164
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• 2008

양액장미에서 발생하는 뿌리혹병에 대해 2003년부터 2007년 까지 피해상황을 조사하였다. 장미 뿌리혹병은 최고 38.1%까지 발생하였으며, 양액재배하는 장미에서 피해가 더욱 심하였다. 전형적인 뿌리혹병 병징은 뿌리와 지제부에 주로 발생하여 생육을 지연시키며 발근억제 뿐아니라 수량감소를 초래하였다. 삽목과정에서 뿌리혹병에 감염될 경우 발근율이 57.5%로 건전주에 비해 현저히 낮아지는 것으로 조사되었다. 뿌리혹병이 감염된 식물체 부위별로 볼 때 지제부에 감염될 경우 새로운 신초생장을 억제하기 때문에 피해가 큰 것으로 나타났다(Fig. 1-B). 인공접종을 통해 생육중인 장미에서 수량에 미치는 영향을 조사한 결과 건전주의 수량이 19.1본/$m^2$에 비해 감염주는 9.5본으로 수량에 있어 큰 차이를 보였고 절화길이 또한 건전주 65.2cm에 비해 44.0cm로 현저히 짧아짐으로서 절화장미의 상품성에도 영향을 주는 것으로 조사되었다. 또한 개화까지 소요되는 일수를 비교해 보면 건전주와 감염주가 각각 51.2일, 39.8일(1차 수확), 60.6일, 52.1일(2차 수확)을 나타내었다. 결론적으로 장미 뿌리혹이 지제부에 감염될 경우 신초의 형성을 억제함으로써 심각한 경제적 수량감소를 초래하여 건전주에 비해 38.7%의 수량감소를 나타내고 개화기까지 소요일수가 8-10일까지 지연되었다.