• 한국조경학회지
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• 제19권2호
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• pp.32-40
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• 1991

Damage to natural resources from inappropriate visitor behavior is a problem faced by National Park management. Based on the data gathered by personal interview and mail questionnaire, this study examines the effects of communication strategies to reduce depreciative behavior in Carlsbad Caverns National Park. One-quarter of Carlsbad Caverns visitors indicates that they have noticed damage to cave formation during their tour. Almost 38% of visitors say that they have witnessed someone touch a formation inside the Caverns. This is a relatively high percentage compared with other depreciative behavior research to refrain from "tattling" on fellow visitors. Two-thirds of the respondents recalls touching formation replicas before entering the Cavern, while almost all visitors (97.9%) say that they have heard the ranger's talk about not touching formation or leaving the trail. Visitors feel that the ranger's talk is more effective in reducing depreciative behavior than the formation replicas, although at least three-fourths of all respondents believes both techniques are effective.

• 대한기계학회논문집
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• 제17권8호
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• pp.1910-1920
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• 1993

An experimental study to investigate the unconventional chip formation called triangulation of chip in cutting with a SPRT (self-propelled rotary tool) is performed using acoustic emission (AE) signal analysis. In doing that, a quantitative model of the AE RMS signal in triangulation with a SPRT is first developed. The predicted results from this model show good correlation between the AE RMS signal and the general characteristics of triangular chip formation. Then, effects of various process parameters such as cutting conditions (cutting speed, depth of cut, oblique angle and normal rake angle) and the work material properties on the chip formation in cutting with a SPRT are explored. Special attention is paid to the work material properties which are found to have significant effects on triangulation.

• 대한환경공학회지
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• 제39권4호
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• pp.220-228
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• 2017

많은 산업 및 도로이동오염원 등으로부터 발생되는 미세먼지는 인간건강과 호흡기에 큰 영향을 미치고 있으며 이에 대한 중요성이 점차 증가하고 있다. 세계보건기구(WHO)에서도 미세먼지($PM_{10}$) 및 초미세먼지$PM_{2.5}$)를 석면 및 비소 등의 물질과 같은 등급인 1급 발암물질로 지정한 이후로 우리나라에서도 지속적인 관심과 연구를 진행해오고 있다. 현재 환경부와 각 지자체별로 미세먼지 및 대기오염정보를 구축하여 제공하고 있지만, 특히 미세먼지 주의보 및 경보발령에 있어서 미세먼지 $PM_{10}$ 및 $PM_{2.5}$ 자료만을 활용하고 있고 미세먼지형성에 영향을 주는NOx, SOx, $NH_3$자료는 활용 및 고려를 하지 않고 있다. 또한 국내 산업별 및 지자체별로 세부적인 미세먼지형성 가능성(particulate matter formation potential) 및 발생되는 미세먼지로 인한 인체호흡기 영향평가(respiratory effects)와 관련된 연구는 많이 진행이 되고 있지 않다. 이에 본 연구의 목적은 국내 11개 산업별 및 시도별로 2001년과 2013년 환경부 및 국립환경과학원에서 제시하고 있는 NOx, SOx, $PM_{10}$, $NH_3$ 자료를 활용하여 미세먼지형성(particulate matter formation potential) 평가와 이로 인한 인체 호흡기 영향을 평가 및 산정하여 비교 제시하고자 하였다. 본 연구결과로는 산업별 및 시도별로 미세먼지형성과 인간건강에 영향을 제시하였으며, 향후 미세먼지 관련 연구에 중요하게 활용할 수 있을 것으로 사료된다.

• 한국분말재료학회지
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• 제8권4호
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• pp.253-257
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• 2001

The effects of mechanical alloying conditions on the formation of Mn-sulfide powders were analyzed. Impeller rotating speed, lubricant coating and added amounts of process control agent(stearic acid) were selected as a process control factor. MnS compounds are synthesized in 3 hours by mechanical alloying at the alternative milling condition. Discontinuous rotating speed of 1200rpm for 4 minutes and 1000rpm for 1 minute shows more effects on the compound formation of MnS. After coating of lubricant on the wall, elementary Mn and sulfur were partially remained by mechanical alloying. The friction effects of the wall and grinding media on the powders are significantly important to form the compound of MnS.

• 미생물학회지
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• 제6권1호
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• pp.12-21
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• 1968

The accelerate effects on the growth rate and the capacity of fermentation of L. delbrukii and B. subtilis was investigated in the Henneberg's medium added by various amounts of cellular components of Chlorella and Scenedesmus and also was investigated in the media added micronutritional elements such as Mn, Fe and Mo, etc. The results in the comparative experiments are as follow; 1. Various amounts of Chlorella cell components in the media accelerated remarkably the lactic acid formation and growth of L. delbrukii. For example, lactic acid formation in the medium of contained 1 percent Chlorella cell components was promoted more than twice effects compare with control. 2. The formation of .alpha.-amylase by B. subtilis in the medium of 2 percent Chlorella cell contents was also promoted more than nine twice effects compare with control. 3. The formation of lactic acid of L. delbruckii in the medium of Scenedesmus cell contents was a little more than in the medium of Chlorella cell contents. 4. The lactic acid fermented level attained with the addition of 0.2-0.25 percent Chlorella cells was the effect of promoting fermentation attained of saturating level at 100$\mu$g. /ml. of Mn and 0. 1 $\mu$g./ml. of Fe.

• 복식
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• 제37권
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• pp.119-132
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• 1998

Niveteen stimulus photographs varied in hue and color scheme of one clothing style of Korean dress worn by a female were used to explore the differences in perceptive effect of clothing cues(color, color scheme, structure) on impression formation and graduate students. The data were analyzed by factor analysis, factor score, ANOVA and Scheffe-test. Results indicate perceptive effects of clothing cues on impression formation are influenced by gender-differences and major-difference of perceivers. Significant gender differences were found in perception of clothing cues on impression effect. Interaction effects were found between clothing cues and gender. Significant major differences were found in perception of clothing cues on impression effect. Interaction effects were found between clothing cues and perceiver's major. Female perceivers and perceivers of major-ing in Liberal Arts reacted to clothing cues on impression formation with greater sensitivity than male perceivers and perceivers of majoring in Natural Sciences. Frequent interaction effects between gender and color of China (cool-warm color), between major difference and color scheme(related color harmony-contrasting color harmony) appeared on factors of impression effect. The influence of perceiver variables on their perception of clothing cues for impression effcet has important implications for gender difference and perceiver's maforing backgroung in a social situation.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.177-177
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• 1998

In the previous report, tetrandrine (TET) and fangchinoline (FAN) showed antithrombotic and antiplatelet aggregation activities. The present study was undertaken to investigate the effects of tetrandrine and fangchinoline on human platelet aggregation, formation of thromboxane B$_2$ and coagulation of platelet poor plasma. TET and FAN inhibited platelet activating factor (PAF) induced human platelet aggregation, but didn't inhibit the specific binding of PAF to its receptor. Meanwhile, TET and FAN also inhibited PAF, thrombin and arachidonic acid induced thromboxane B$_2$ formation in human washed platelets. In addition, neither TET nor FAN showed any anticoagulation activities in the measurement of the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) using human platelet poor plasma. These results suggest that antithrombotic effects of TET and FAN in mice may be mainly related to the antiplatelet aggregation activities, and the antiplatelet aggregation effects may be related to the intracellular messenger system such as TXA$_2$ formation etc., but not to the binding of PAF to PAF-receptor on the platelet membrane directly.

• International Journal of Oral Biology
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• 제45권4호
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• pp.143-151
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• 2020

Streptococcus mutans and Streptococcus sobrinus play important roles in dental caries. Coptis chinensis is a natural product with antimicrobial activity against enterobacteria; however, its effects on oral streptococci are still unknown. Therefore, the effects of C. chinensis on the growth and biofilm formation of the representative cariogenic bacteria S. mutans and S. sobrinus were investigated for the possible use of C. chinensis as an anticaries agent. The C. chinensis extract was diluted with sterile distilled water, and 0.1-2.5% of the extract was used in the experiment. The effects of the C. chinensis extract on the growth and glucan formation of S. mutans and S. sobrinus were measured by viable cell counting and spectrophotometry at 650 nm absorbance, respectively. Crystal violet staining was also carried out to confirm the C. chinensis extract's inhibitory effect on biofilm formation. The C. chinensis extract significantly inhibited the growth of S. mutans and S. sobrinus at concentrations of ≥ 0.3% as compared with the control group. The viable cell count of colonies decreased by 1.7-fold and 1.2-fold at 2.5% and 1.25%, respectively, compared with the control group. The biofilm formation of S. mutans and S. sobrinus was inhibited by > 20-fold at C. chinensis extract concentrations of ≥ 1.25% as compared with the control group. In summary, the C. chinensis extract inhibited the growth and biofilm and glucan formation of S. mutans and S. sobrinus. Therefore, C. chinensis might be a potential candidate for controlling dental caries.

• 천문학회보
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• 제46권2호
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• pp.37.1-37.1
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• 2021

Observations suggest the star formation in nuclear rings of barred galaxies proceeds episodically in time and sometimes asymmetrically in space. Existing theories and numerical simulations suggest that the episodic star formation is perhaps due to either supernova feedback combined with fluid instabilities or time-varying mass inflow rate. However, it has been challenging to discern what dominates in shaping the star formation history because the effects of the inflow and feedback are blended in global simulations of nuclear rings. To understand their effects separately, we construct semi-global models of nuclear rings, which treat the mass inflow rate as a model parameter. By running simulations with the inflow rates kept constant or oscillating in time, we find that the star formation rate (SFR) of the rings varies coherently with the inflow rate, while the feedback is responsible only for stochastic fluctuations of the SFR within a factor of two. The feedback instead plays an important role in maintaining the vertical dynamical equilibrium and setting the depletion time. While the asymmetry in the inflow does not necessarily lead to the asymmetry in the star formation, we find that the rings undergo a transient period of lopsided star formation when the inflow rate of only one dust lane is suddenly increased.

• Restorative Dentistry and Endodontics
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• 제44권1호
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• pp.4.1-4.10
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• 2019

Objectives: Biofilm formation is critical to dental caries initiation and development. The aim of this study was to investigate the effects of nicotine exposure on Streptococcus mutans (S. mutans) biofilm formation concomitantly with the inhibitory effects of sodium chloride (NaCl), potassium chloride (KCl) and potassium iodide (KI) salts. This study examined bacterial growth with varying concentrations of NaCl, KCl, and KI salts and nicotine levels consistent with primary levels of nicotine exposure. Materials and Methods: A preliminary screening experiment was performed to investigate the appropriate concentrations of NaCl, KCl, and KI to use with nicotine. With the data, a S. mutans biofilm growth assay was conducted using nicotine (0-32 mg/mL) in Tryptic Soy broth supplemented with 1% sucrose with and without 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI. The biofilm was stained with crystal violet dye and the absorbance measured to determine biofilm formation. Results: The presence of 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI significantly inhibited (p < 0.05) nicotine-induced S. mutans biofilm formation by 52%, 79.7%, and 64.1%, respectively. Conclusions: The results provide additional evidence regarding the biofilm-enhancing effects of nicotine and demonstrate the inhibitory influence of these salts in reducing the nicotine-induced biofilm formation. A short-term exposure to these salts may inhibit S. mutans biofilm formation.