• Korean Journal of Plant Resources
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• v.17 no.1
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• pp.67-74
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• 2004

This study was carried out to investigate the structural characteristics of Taxus cuspidate communities in Mt. DuckYoo. The vegetation was consisted of 20 species in the T$_1$(tree) layer, 26 species in the T$_2$(subtall tree) layer, 26species in S(shrub) layer, and 56 species in the H(herb) layer. The dominant species of Mt. Duckyoo was Taxus cuspidata in the T$_1$ Layer, Acer tschonoskii var. rubripes in the T$_2$ Layer, Tripterygium regelii and Acer tschonoskii var. rubripes in the S Layer and Sasa borealis in the H Layer. According to the diameter distribution of high ranking five species in T$_1$, T$_2$ layer at natural Taxus cuspidata communities, these forests may be gradually replaced by Quercus mongolica, Tripterygium regelii. The composition of biological type was Ph-D$_1$-R$\sub$5/-e.

• Korean Journal of Plant Resources
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• v.17 no.1
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• pp.58-66
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• 2004

This study was carried out to investigate the structural characteristics of Taxus cuspidate communities in Mt. DuckYoo. The vegetation was consisted of 20 species in the T$_1$(tree) layer, 26 species in the T$_2$(subtall tree) layer, 26species in S(shrub) layer, and 56 species in the H(herb) layer. The dominant species of Mt. Duckyoo was Taxus cuspidata in the T$_1$ Layer, Acer tschonoskii var. rubripes in the T$_2$ Layer, Tripterygium regelii and Acer tschonoskii var. rubripes in the S Layer and Sasa borealis in the H Layer. According to the diameter distribution of high ranking five species in T$_1$, T$_2$ layer at natural Taxus cuspidata communities, these forests may be gradually replaced by Quercus mongolica, Tripterygium regelii. The composition of biological type was Ph-D$_1$-R$\_$5/-e.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2455-2460
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• 2013

Second-order rate constants ($k_N$) have been measured spectrophotometrically for the nucleophilic displacement reactions of 4-nitrophenyl X-substituted-cinnamates (4a-4e) and Y-substituted-phenyl cinnamates (5a-5e) with Z-substituted-phenoxide anions in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The Hammett plot for the reactions of 4a-4e with 4-chlorophenoxide (4-$ClPhO^-$) consists of two intersecting straight lines, which might be taken as a change in the rate-determining step (RDS). However, it has been concluded that the nonlinear Hammett plot is not due to a change in the RDS but is caused by stabilization of the ground state of substrates possessing an electron-withdrawing group in the cinnamoyl moiety through resonance interactions, since the Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}X=0.89$ and r = 0.58. The Br${\o}$nsted-type plot for the reactions of 4-nitrophenyl cinnamate (4c) with Z-substituted-phenoxides is linear with ${\beta}_{nuc}=0.76$. The Br${\o}$nsted-type plot for the reactions of Y-substituted-phenyl cinnamates (5a-5d) with 4-chlorophenoxides (4-$ClPhO^-$) is also linear with ${\beta}_{lg}=-0.72$. The Hammett plot correlated with ${\sigma}^-$ constants for the reactions of 5a-5d results in a much better linear correlation than that correlated with ${\sigma}^o$ constants, indicating that a partial negative charge develops on the O atom of the leaving aryloxide. Thus, the reactions have been concluded to proceed through a concerted mechanism.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.552-554
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• 1999

Phonon scattering and impact ionization models have been presented to analyze hot carrier transport in high energy region, using full band model and Fermi's golden rule. We have investigated temperature dependent properties for impact ionization process of Si using realistic energy band structures at 77K and look. The realistic full band model, obtained from the empirical pseudopotential method with local from factors, is used to calculate scattering rate. The accurate calculation of impact ionization rate requires the use of a wavevector- and frequency-dependent dielectric function ξ ( q,$\omega$). The empirical phonon scattering rate P$\sub$ph/, is given by deriving from linear function for P$\sub$ph/ versus D(E) since the phonon scattering rate is linearly depended on density of states D(E). Impact ionization rate p,, is calculated from the first principle's theory. and fitted by modified Keldysh formula having power of above 2.

• Journal of Information Management
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• v.39 no.2
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• pp.185-209
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• 2008

This study was carried out on the citations within the chemistry field Ph.D. dissertations to ascertain what types of documents are the most frequently used in the research process, the most frequently consulted journals and obsolescence rate of the journals. The analysis covered 42 doctoral theses presented at 'K' university in Seoul from 2000 to 2008. The results obtained from the 3,258 citations revealed that the most frequently used documents were Academic Journal, which accounted for 91 percent of the total; 27 journals met 50 percent of the information needs; and the age of 50 percent of the citations was no older than 9 years. Finally, the results can be used as a tool for the collection management of the library. and Researcher with the chemistry field Ph.D. dissertation.

• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.55.1-55.12
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• 2020

Objectives: This study investigated the effects of physically damaged and resin-contaminated tips on radiant emittance, comparing them with new undamaged, non-contaminated tips using 3 pieces of spectrophotometric laboratory equipment. Materials and Methods: Nine tips with damage and/or resin contaminants from actual clinical situations were compared with a new tip without damage or contamination (control group). The radiant emittance was recorded using 3 spectrophotometric methods: a laboratory-grade thermopile, a laboratory-grade integrating sphere, and a portable light collector (checkMARC). Results: A significant difference between the laboratory-grade thermopile and the laboratory-grade integrating sphere was found when the radiant emittance values of the control or damaged/contaminated tips were investigated (p < 0.05), but both methods were comparable to checkMARC (p > 0.05). Regardless of the method used to quantify the light output, the mean radiant emittance values of the damaged/contaminated tips were significantly lower than those of the control (p < 0.05). The beam profile of the damaged/contaminated tips was less homogeneous than that of the control. Conclusions: Damaged/contaminated tips can reduce the radiant emittance output and the homogeneity of the beam, which may affect the energy delivered to composite restorations. The checkMARC spectrophotometer device can be used in dental offices, as it provided values close to those produced by a laboratory-grade integrated sphere spectrophotometer. Dentists should assess the radiant emittance of their light-curing units to ensure optimal curing in photoactivated, resin-based materials.

• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.312-317
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• 2001

7'-Aldehyde-nucleosides analogue (2a, 2c) were synthesized from 6-N-benzoyl-2',3'-O-isopropylideneadenosine and uridine. The condensation of 2 with ethoxycarbonylmethylene Wittig reagent produced the adenosine and uridine analogues containing extended conjugated diene and ethoxycarbonyl group, ethyl-1',5',6',7',8'-pentadeoxy-1'-(adenin-9-yl)-$\beta$-D-ribo-nona-5'(E),7'(E)-dienofuranuronate (4b) and ethyl-1'. 5',6',7',8'-pentadeoxy-1'-(uracil-1-yl)-$\beta$-D-ribo-nona-5'(E),7'-(E)-dienofuranuronate (4c). 9-[8',8'-dibromo-5',6',7',8' -tetradeoxy-$\beta$-D-ribo-octa-5'(E),7'(E)-diene]nucleosides (6b, 6c) were also prepared from 2 with similar method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.451-458
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• 2002

Absorptive type SP3T(Single Pole Three Throw) and SP8T switch modules over the 6-18 GHz are designed and fabricated. The epitaxial structure of GaAs PIN diode for switch modules are designed for low loss and high power capability. The maximum input power of SP3T and SP8T switch modules are 2 W and 1 W, respectively. The switching time with driver circuit is less than 130 nsec. The maximum insertion loss of SP3T switch module and SP8T module shows 2.8 dB and 4.2 dB, respectively. The isolation between input port and output port is more than 55 dB. Two switch modules for electronic warfare system have passed the environment tests of the related test items.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.135-135
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• 1993

신호전달과정에 중요한 역할을 하고 있는 다기능 serinei/threonine 단백질인산화효소인 protein kinase C(PKC)의 연구를 위해 이 효소의 정제를 뇌에서 착수하였다 PKC의 활성측정을 myelin basic protein을 기질로 하여 20 mM Tris 완충용액 PH 7.5, 0.15 mM [${\gamma}$-$^{32}$P]ATP(3 $\times$ $10^{5}$ cpm), 0.1 mM $Ca^{2＋}$, 10$\mu\textrm{g}$ phosphatidylserine과 2$\mu\textrm{g}$ diolein을 넣어 반응시켰다. 반응은 TCA로 정지시킨 후 방사성 단백질을 Millipore filter paper로 걸러 섬광 계수기로 읽었다. Cytosol PKC의 정제과정은 첫 단계에서 DEAE-cellulose를 사용하였으며, phenyl sepharose CL-4B와 protamine agarose를 연속적으로 이용하여 800배의 정제에 성공했다. SDS-PACE 상에서 80 kD로 나타났으며 순도는 95 % 이상이였다. 이를 이용 PKC의 각종 기질 연구에 착수하기 시작했으며, 이중 MBP의 인산화연구를 통한 myelin의 안정성과 MBP와의 구조 관계가 일부 수행되고 있다 연차적으로 PKC와 이와 관련된 단백질의 특성을 살피기 위해 뇌의 PKC 기질 중 cold stress를 통해 환경에 민감한 것을 찾고 있으며, 현재 autoradiography를 이용해 80 kD, 54 kD, 49 kD와 35 kD의 단백질이 연구대상이 되고있다. 그 중 49 kD는 B-50(또는 GAP43, neuromodulin이라고도 함)일 가능성이 높아 이 단백질 조절과 PKC 활성화 사이의 관계 정립이 흥미로운 과제로 대두되고 있다.다.

• The Korean Nurse
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• v.34 no.5
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• pp.68-81
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• 1996

In order to see the development of nursing related research activities in Korea over the last three decades, abstracts of almost all of the Masters and Ph. D. theses that had appeared from 1961 up to August 1991 were collected. Number of theses amounted to 1779(76%) out of a total of 2354 theses. We analysed the papers research patterns, which are research problem, research design, population, place. Here is what we have found. 1). The types of research problems were as follows. 58.0% papers did factor-analysis, 29.1% studied factor~relations, 11.4% situation relations and 1.5% did situation~creations. With respect to the years, we found that the factor-analysis papers decreased with time but the factor~relating, the situation -relating, and the situation~creating papers were increased. Especially the situation-creating paper increased notably since the 80s'. Relating to the kind of degrees, we found that for M.S.theses 60.2% of the papers did factor-analysis, 29.0% the factor-relating studies, 10.4% the situation-relating studies, and 0.4% the situation -creating studies. For the Ph.D. theses 30.5% did the factor~relating, 30.5% the situation-relating. and 20.0% the situation-creating papers. Considering the graduate schools, we found that the regular graduate schools and the graduate school of education produced about the same number of papers of each kind, but 81.2% and 64.6% papers produced by the graduate school of public health and the graduate school of public administration, respectively, did the factor-analysis thus taking majority of the papers. 2). Research designs were as follows : 10.8% experimental studies, 89.0% non experimental studies, and 0.2% quality studies were found. So the majority of the research designs were nonexperimental. We see a meaningful difference between the M.S.theses showing 9.8% experimental studies and 90. 1% nonexperimental studies. and Ph.D. theses showing 28.4% experimental studies and 68. 4% nonexperimental studies. Relating to the graduate schools, we find that the regular graduate schools and the graduate school of education with 15.8% and 10.6% experimental studies respectively, did a little more experimental studies than other schools. but still the regular graduate schools, the graduate school of public health, and the graduate school of education each show 83.8%, 97.4%, and 89.4% nonexperimental studies, so most schools are concentrating on nonexperimental studies. 3). On the relation between research problem and research design, experimental studies show 88.0% of situation-relations and 6.8% of factor-relations. Nonexperimental studies had factor-analysis taking the majority by 64.4% and 31.9% were factor-relations. 4). On the research subjects, we have 90.8% of the papers dealing with a single subject and 9.2% of the papers dealing with two or more subjects. Most of the research subjects are patients or nurses for the regular graduate schools and the graduate school of education, but for the graduate school of administration as much as. 60% of the studies took nurses as subjects. Subjects taken were patients, nurses. and students in decreasing order for the M.S. theses and for patients, women, and nurses again in decreasing order for the Ph.D.theses. 5). On the places of study, we've had 47, 8% of the studies done in hospital rooms, 15, 1% in schools, and 9, 6% in the local community, With respect to the years, we found 36.7% in the hospital rooms, 22.4% in the schools, and 14, 8% in the local communities in the 1970's and 50.1%in the hospital rooms, 13.4% in the schools. and 9, 2% in the local communities in the 80's.