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Recent Progress in Air Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2007 (설비공학 분야의 최근 연구 동향 : 2007년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Shin, Dong-Sin;Choi, Chang-Ho;Lee, Dae-Young;Kim, Seo-Young;Kwon, Yong-Il
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.12
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    • pp.844-861
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    • 2008
  • The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.

Recent Progress in Air Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 (공기조화, 냉동 분야의 최근 연구 동향: 2006년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Shin, Dong-Sin;Choi, Chang-Ho;Lee, Dae-Young;Kim, Seo-Young;Kwon, Yong-Il
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.6
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    • pp.427-446
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    • 2008
  • A review on the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 has been accomplished. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro heat exchanger and siphon cooling device using nano-fluid. Traditional CFD and flow visualization methods were still popular and widely used in research and development. Studies about diffusers and compressors were performed in fluid machinery. Characteristics of flow and heat transfer and piping optimization were studied in piping systems. (2) The papers on heat transfer have been categorized into heat transfer characteristics, heat exchangers, heat pipes, and two-phase heat transfer. The topics on heat transfer characteristics in general include thermal transport in a cryo-chamber, a LCD panel, a dryer, and heat generating electronics. Heat exchangers investigated include pin-tube type, plate type, ventilation air-to-air type, and heat transfer enhancing tubes. The research on a reversible loop heat pipe, the influence of NCG charging mass on heat transport capacity, and the chilling start-up characteristics in a heat pipe were reported. In two-phase heat transfer area, the studies on frost growth, ice slurry formation and liquid spray cooling were presented. The studies on the boiling of R-290 and the application of carbon nanotubes to enhance boiling were noticeable in this research area. (3) Many studies on refrigeration and air conditioning systems were presented on the practical issues of the performance and reliability enhancement. The air conditioning system with multi indoor units caught attention in several research works. The issues on the refrigerant charge and the control algorithm were treated. The systems with alternative refrigerants were also studied. Carbon dioxide, hydrocarbons and their mixtures were considered and the heat transfer correlations were proposed. (4) Due to high oil prices, energy consumption have been attentioned in mechanical building systems. Research works have been reviewed in this field by grouping into the research on heat and cold sources, air conditioning and cleaning research, ventilation and fire research including tunnel ventilation, and piping system research. The papers involve the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies on indoor air quality took a great portion in the field of building environments. Various other subjects such as indoor thermal comfort were also investigated through computer simulation, case study, and field experiment. Studies on energy include not only optimization study and economic analysis of building equipments but also usability of renewable energy in geothermal and solar systems.

Simultaneous determinations of anthracycline antibiotics by high performance liquid chromatography coupled with radial-flow electrochemical cell (고성능 액체 크로마토그래피/방사흐름 전기화학전지를 이용한 안트라사이클린계 항생제의 동시 정량)

  • Cho, Yonghee;Hahn, Younghee
    • Analytical Science and Technology
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    • v.20 no.4
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    • pp.308-314
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    • 2007
  • The analytical method of HPLC with the radial-flow electrochemical cell (RFEC) has been developed to determine doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin simultaneously by employing a reversed-phase chromatography. Anthracyclines were detected at -0.74 V vs. a Ag/AgCl (0.01 M NaCl) reference electrode, a potential of diffusion current plateau in the mobile phase. At a $V_f$ of 1.0 mL/min doxorubicin, epirubicin, daunorubicin and idarubicin appeared at a retention time ($t_r$) of 6.4 min, 7.4 min, 12.7 min and 18.4 min, respectively, while at a $V_f$ of 0.6 mL/min, doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin appeared at a $t_r$ of 9.9 min, 11.5 min, 13.5 min, 19.6 min and 28.7 min, respectively. The linearity between each anthracycline injected ($2.40{\times}10^{-7}M{\sim}1.42{\times}10^{-5}M$) and peak area (charge) was excellent with the square of the correlation coefficient ($R^2$) higher than 0.999. The detection limits were $1.0{\times}10^{-8}M{\sim}1.5{\times}10^{-7}M$ for the five anthracyclines. Within-day precision for the five anthracyclines were in reasonable relative standard deviations less than 3 % ($1.00{\times}10^{-6}M{\sim}1.42{\times}10^{-5}M$) except the lower concentrations less than $0.7{\mu}M$. Solid phase extractions of $1.00{\times}10^{-5}M$ epirubicin, $0.48{\times}10^{-5}M$ nogalamycin and $1.52{\times}10^{-5}M$ daunorubicin from human serum with a $C_{18}$ cartridge resulted in 97 %, 100 % and 90 % of recoveries, respectively.

A Study of Yangshangsun(楊上善)'s theory of three-yum and three-yang(三陰三陽) - focus on attribute of three-yum and three-yang(三陰三陽), the bolt-leaf-hanges(關闔樞) theory, large of small of gi-blood(氣血多少) (양상선(楊上善)의 삼음삼양(三陰三陽) 학설(學說)에 대한 연구 - 음양속성(陰陽屬性), 관합추(關闔樞), 기혈다소(氣血多少)를 중심으로 -)

  • Lee, Yong Bum
    • Journal of Korean Medical classics
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    • v.10
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    • pp.450-493
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    • 1997
  • Three-yum and three-yang(三陰三陽) is the change state of yum-yang(陰陽) which is caused by six gi(六氣). They mean the flow of six gi(六氣) which exist throughout the viscera, the channel(經絡), and the skin. But it is not easy to understand the meaning because the contents of the attribute of three-yum and three-yang(三陰三陽), the bolt-leaf-hanges(關闔樞) theory and large or small of gi-blood(氣血多少) which is the main clue that explain it in ${\ll}$Somun(素問)${\gg}$ and ${\ll}$Yeongchu(靈樞)${\gg}$ don't coincide with each other. I, the writer, tried to understand the uncertain meaning and the contents which are written about three points above differently in each of the books that are ${\ll}$Somun(素問)${\gg}$ and ${\ll}$Yeongchu(靈樞)${\gg}$. So, from that the course that the book, ${\ll}$Huangjenegeong(黃帝內經)${\gg}$ is handed down is so relatively simple in a wood block-printed book, that the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ has less wong-words than the Somun(素問) and the Yeongchu(靈樞), and from that Yangshangsun(楊上善) wrote the note in the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ by royal order about 100 years former than Wangbing(王氷), as making projects of Yangshangsun(楊上善)'s note and the original of the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ which has relation to the yum-yang(陰陽) attribute of three-yum and three-yang(三陰三陽), the bolt-leaf-hanges(關闔樞) theory, and the large or small of gi-blood(氣血多少) and researching the Yangshangsun(楊上善)'s theory. The result is summarized like this. First, wherease the order of the change of three-yum and three-yang(三陰三陽) which is explained by Yangshangsun(楊上善) consider the change of yangi(陽氣) in body most important, the order of the change gaeggi(客氣)'s three-yum and three-yang(三陰三陽) considers chungi(天氣) most important, and the order of jugi(主氣)'s three-yum and three-yang(三陰三陽) considers jigi(地氣)'s change of ohaeng(五行) most important. If the order of change three-yum and three-yang(三陰三陽) in the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ is considered, each of taeyang(太陽) and soyum(少陰) are expressed as the base of yum-yang(陰陽) and yangmeong(陽明) and taeyum(太陰) are expressed as the palmy days of yum-yang(陰陽), soyang(少陽) and gyolyum(厥陰) are expressed as pacemaker(樞杻) which controls the change of yum-yang(陰陽). Thus, each has something in common that is fettered by the inside and outside. In the flow of channel(經絡), taeyang(太陽) and soyum(少陰) take charge of the behind of body, yangmeong(陽明) and taeyum(太陰) take charge of the front of body and soyang(少陽) and gyolyum(厥陰) take of the side of body. Second, in Yangshangsun(楊上善)'s bolt-leaf-hanges(關闔樞) theory, three-yum(三陰) is regarded as inside, three-yang(三陽) as outside, so when bolt, leaf and hanges fulfil their duties in inside and outside, the life(life force) is thought to be revealed normally. It is impossible to understand the bolt-leaf-hanges with the conception of the inside and outside which divide three-yum and three-yang(三陰三陽) into taeyang-soyum(太陽-少陰), yangmeong-taeyum(陽明-太陰), soyang-gyolyum(少陽-厥陰) according to yum-yang(陰陽) attribute, hence it need the special conception that is taeyang(太陽)-taeyum(太陰), yangmeong(陽明)-gyolyum(厥陰), soyang(少陽)-soyum(少陰) which center on their duties in inside and outside. In the denunciation of the word open(開) and bolt(關), because Yangshangsun(楊上善) said that the duities of taeyang(太陽) and taeyum(太陰) are shutter(閉禁), bolt(關) is coincided with that significance. Third, with explaining the large or small of gi-blood(氣血多少) of three-yum and three-yang(三陰三陽), Yangshangsun(楊上善) expressed the inside and outside either in the same way or differently. Because the inside and outside is interior of body and exterior of body, it is the explanation that is noticed by the fact that the property of large or small of gi-blood(氣血多少) is either able to be same or different. In this viewpoint, if we unite the contents about large or small of gi-blood(氣血多少) of ${\ll}$Somun(素問)${\gg}$, ${\ll}$Yeongchu(靈樞)${\gg}$, we will find that the descriptions of large or small of gi-blood(氣血多少) of three-yang(三陽) in ${\ll}$Somun(素問)${\gg}$ ${\ll}$Yeongchu(靈樞)${\gg}$ correspond with the ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$, but in three-yum(三陰), the contrary presentations exit. The reason is that large or small of gi-blood(氣血多少) of three-yum(三陰) isn't only expressed as che(體) in the point of che-yong(體用), but as a point of yong(用) that is a phenomenon. As researching the original of ${\ll}$Huangjenegeongtaeso(黃帝內經太素)${\gg}$ and Yangshangsun(楊上善)'s notes as a center about three problems that are yum-yang(陰陽) attribute, the bolt-leaf-hanges(關闔樞) and large or small of gi-blood(氣血多少) of three-yum and three-yang(三陰三陽), I, the writer, tried to explain the part which is written differently or has uncertain conception in the book ${\ll}$Somun(素問)${\gg}$ and the book ${\ll}$Yeongchu(靈樞)${\gg}$, but the concrete result of the work like this will be judged according to the question how many theories are correspondent with real presence at a sickbed. Hence, the work to veryfy the theories in the future will be left as assignment.

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Sorption of Arsenite Using Nanosized Mackinawite (FeS)-Coated Silica Sand (나노 크기 매킨나와이트로 코팅된 규사를 이용한 아비산염의 흡착)

  • Lee, Seungyeol;Kang, Jung Chun;Park, Minji;Yang, Kyounghee;Jeong, Hoon Young
    • Journal of the Mineralogical Society of Korea
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    • v.25 no.4
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    • pp.185-195
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    • 2012
  • Due to the high reduction and sorption capacity as well as the large specific surface area, nanosized mackinawite (FeS) is useful in reductively transforming chlorinated organic pollutants and sequestering toxic metals and metalloids. Due to the dynamic nature in its colloid stability, however, nanosized FeS may be washed out with the groundwater flow or result in aquifer clogging via particle aggregation. Thus, these nanoparticles should be modified such as to be built into permeable reactive barriers. This study employed coating methods in efforts to facilitate the installation of permeable reactive barriers of nanosized mackinawite. In applying the methods, nanosized mackinawite was coated on non-treated silica sand (NTS) and chemically treated silica sand (CTS). For both silica sands, the maximum coating of mackinawite occurred around pH 5.4, the condition of which was governed by (1) the solubility of mackinawite and (2) the surface charge of both silica and mackinawite. Under this pH condition, the maximum coating by NTS and CTS were found to be 0.101 mmol FeS/g and 0.043 mmol FeS/g respectively, with such elevated coatings by NTS likely linked with impurities (e.g., iron oxides) on its surface. Arsenite sorption experiments were performed under anoxic conditions using uncoated silica sands and those coated with mackinawite at the optimal pH to compare their reactivity. At pH 7, the relative sorption efficiency between uncoated NTS and coated NTS changed with the initial concentration of arsenite. At the lower initial concentration, uncoated NTS showed the higher sorption efficiency, whereas at the higher concentration, coated NTS exhibited the higher sorption efficiency. This could be attributed to different sorption mechanisms as a function of arsenite concentration: the surface complexation of arsenite with the iron oxide impurity on silica sand at the low concentration and the precipitation as arsenic sulfides by reaction with mackinawite coating at the high concentration. Compared to coated NTS, coated CTS showed the lower arsenite removal at pH 7 due to its relatively lower mackinawite coating. Taken together, our results indicate that NTS is a more effective material than CTS for the coating of nanosized mackinawite.

Improvement of Tentative Korean Standard Differentiation of the Symptoms and Signs for Stroke for Clinical Application (중풍변증표준안 진료기록부 임상적용을 위한 증례기록부와 표준작업지침서의 개선과정)

  • Lee, Min-Goo;Kang, Byeong-Kab;Kim, Bo-Young;Ko, Ho-Yeon;Choi, Sun-Mi;Seol, In-Chan;Jo, Hyun-Kyung;Yun, Jong-Min;Moon, Byung-Soon;Lee, In
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.21 no.1
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    • pp.347-351
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    • 2007
  • This study was done to report the improvement of second case report form(CRF) and standard operating procedure(SOP) of Tentative Korean Standard Differentiation of the Symptoms and Signs for Stroke. We were in charge of developing case report form(CRF) and educating the investigators. In the process of this project, we needed to develop standard operating procedure(SOP) for this CRF. So we made Tentative Korean Standard Differentiation of the Symptoms and Signs for Stroke and tried clinical application at Department of Oriental Internal Medicine of Wonkwang University and Daejeon University in 2005. And in this pilot study we can find out some problems and need to improve it. We strengthen the incision and exclusion criteria of CRF We canceled the Chief complains entry for efficiency. We reflected the decision of Stroke standard committee. We reduced the differentiation index of CRF to promote efficiency and accuracy. We rearranged the order of the differentiation index to promote rationality and practicality. We regulated detail item belonging to Differentiation index. We used a colloquialism in question. We inserted flow chart in SOP. We inserted picture of diagnostic index.

A Study on Structural Maintenance of 'Old Wall' Designated as National Registered Cultural Heritage (국가등록문화재로 지정된 옛 담장의 정비 양상)

  • So, Hyun-Su;Jeong, Myeong-Seok
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.41 no.1
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    • pp.21-34
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    • 2023
  • This study identified the materials and construction methods of 'Old Wall' in 13 villages which were designated as National Registered Cultural Heritage at the time of designation and examined the their structural changes based on field survey. The results are as follows: First, the 'Old Wall' consisted of 10 Soil-Stone Wall and 5 Stone Wall. At the time of designation, Stone Wall, which was built irregularly by dry-construction of natural stones, is similar in shape, but Soil-Stone Wall showed difference by the construction method of making used stones, joints, and faces. Second, the study extracted the changes of 'Old Wall' by repair and examined the changes of construction methods as well as the substitution and addition of materials of structure. The wall-roof was built with cement roof-tile and asbestos slate which have the advantage improve durability and cost-effectiveness. In addition, tile-mouth soil was added to korean traditional roof-tile to prevent rainwater from flowing in. Besides, to improve constructional convenience, the natural stone of the wall-body was replaced with blast stone, float stone and cut stone. Cement block, cement brick and cement mortar were frequently used to repair as well. As Soil-Stone Wall was transformed from irregular pattern-construction to comb pattern-construction and wet-construction was changed to dry-construction, it caused landscape and structural problems. Also, the layer of cement mortar applied to wall-foundation blocked the flow of rainwater that was induced by dry-construction of natural stones. Third, the study regarded that the problem with the repair of 'Old Wall' may occur as it is located in living space, because the owner of the wall could repair for the minor damages without technical knowledge. In addition, it is difficult for repair companies in charge of maintenance of Cultural Heritage to supply local materials, and it is differential construction specifications are not applied.

Trend Analysis of Curriculum Application Status of 2015 Revised Integrated Science and Scientific Laboratory Experiment Curriculum (2015 개정 통합과학과 과학탐구실험 교육과정의 2차 년도 적용 현황 추이 분석)

  • Kwak, Youngsun
    • Journal of the Korean Society of Earth Science Education
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    • v.13 no.1
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    • pp.53-63
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    • 2020
  • The purpose of this study is to analyze the current status of the second year of application of Integrated Science and Science Laboratory Experiments, which are common courses of high school, and to explore suggestions for curriculum development in the future. To this end, the results of the survey of a total of 244 science-core and general high schools were compared with the survey result of 2018 school year. In addition, in-depth interviews were conducted with nine science teachers of the focus group to discuss the current state of curriculum implementation. According to the results, as in the first year, most of the Integrated Science courses were implemented in 6-8 units, and in most schools the number of teachers in charge of Integrated Science per class were 3-4. In the teacher's focus group interview, teachers insisted that Integrated Science requires integrated teaching approaches and is good for generating students' interest, but it is difficult to implement process-based assessment due to issues such as ensuring fairness of assessment. Most of Science Laboratory Experiments courses were implemented in two semesters, one unit per semester, and there was little link between Integrated Science and Science Laboratory Experiments because of the different teaching staff. The school life record entry method of Science Laboratory Experiments has been changed to criterion-based assessment starting in 2019, so students' satisfaction or flow of classes is much better than expected, and teachers can teach without burden. Based on the research results, ways to support the settlement of Integrated Science and Science Laboratory Experiments as common subjects, and ways to improve those subjects in the next curriculum revision were suggested.

Physical properties and intracellular uptake of polyethyleneglycol-incorporated cationic liposomes (폴리에틸렌글리콜이 도입된 양이온성 리포솜의 물리적 특성 및 세포이입효과)

  • Jung, Soon-Hwa;Jung, Suk-Hyun;Kim, Sung-Kyu;Seong, Ha-Soo;Cho, Sun-Hang;Shin, Byung-Cheol
    • Journal of Pharmaceutical Investigation
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    • v.38 no.1
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    • pp.15-21
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    • 2008
  • Liposomes as one of the efficient drug carriers have some shortcomings such as their short circulation time, fast clearance from human body by reticuloendothelial system (RES) and limited intracellular uptake to target cell. In this study, polyethylenglycol (PEG)-incorporated cationic liposomes were prepared by ionic complexation of positively charged liposomes with carboxylated polyethyleneglycol (mPEG-COOH). The cationic liposomes had approximately $98.6{\pm}1.0nm$ of mean particle diameter and $42.8{\pm}0.8mV$ of zeta potential value. The PEG-incorporated cationic liposomes had $110.1{\pm}1.2nm$ of mean particle diameter with an increase of about 10 nm compared to the cationic liposomes. Zeta potential value of them was $12.9{\pm}0.6mV$ indicating 30mV decrease of cationic charge compared to the cationic liposomes. The amount of PEG which was incorporated onto the cationic liposomes was assayed by using picrate assay method and the incorporation efficiency was $58.4{\pm}1.1%$. Loading efficiency of model drug, doxorubicin, into cationic liposomes or PEG-incorporated cationic liposomes was about $96.0{\pm}0.7%$. Results of intracellular uptake which were evaluated by flow cytometry analysis of doxorubicin loaded liposomes showed that intracellular uptake of PEG-incorporated cationic liposomes was higher than the cationic liposomes or DSPE-mPEG liposomes. In addition, cytotoxicity of PEG-incorporated cationic liposomes was comparable to cationic liposomes. Consequently, the PEG-incorporated cationic liposomes of which surface was incorporated with PEG by ionic complex may be applicable as anticancer drug carriers that can increase therapeutic efficacy.

Analysis of related words for each private security service through collection of unstructured data

  • Park, Su-Hyeon;Cho, Cheol-Kyu
    • Journal of the Korea Society of Computer and Information
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    • v.25 no.6
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    • pp.219-224
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    • 2020
  • The purpose of this study is mainly to provide theoretical basis of private security industry by analyzing the perception and flow of private security from the press-released materials according to periodic classification and duties through 'Big Kinds', a website of analyzing news big data. The research method has been changed to structured data to allow an analysis of various scattered unstructured data, and the keywords trend and related words by duties of private security were analyzed in growth period of private security. The perception of private security based on the results of the study was exposed a lot by the media through various crimes, accidents and incidents, and the issues related permanent position. Also, it tended to be perceived as a simple security guard, not recognized as the area of private security, and judging from the high correlation between private security and police, it was recognized not only as a role to assist the police force, but also as a common agent in charge of the public peace. Therefore, it should objectively judge the perception of private security, and through this, it is believed that it should be a foundation for recognizing private security as a main agent responsible for the safety of the nation and maintaining social orders.