• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.362-372
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• 2011

The relationships among total epiphytes, algal epiphytes and eelgrass ($Zostera$ $marina$ L.) were studied at eelgrass medows from July, 1998 to July, 1999 in Yulim-ri, Yeosu, Korea. Epiphytic diatoms on eelgrass leaves were observed from July to December 1998. From the results of this study, we inferred the following three (3) conclusions : 1) As eelgrass grew older, biomass of epiphytes increased, according to relationships between the leaf length and area of eelgrass and biomass (DW, AFDW and Chl. $a$) of epiphytes. 2) According to the ratio of dry weight, ash-free dry weight and Chlorophyll of epiphytes, the algae with calcareous or siliceous skeletons, such as coralline algae or diatoms, were dominated in the epitphytic algae community. 3) The autotrophic index (AI) calculated from AFDW and Chl. $a$ of epiphytes varied from 151 to 375. However, the period of autotrophic community was shorter than heterotrophic community and the value of AI was high. From these results, we inferred that heterotrophic community, including detritus or microorganisms were dominated in the most of research period.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.15-20
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• 2019

We developed a novel depth-of-interaction positron emission tomography (PET) detector using wavelength shifting (WLS) fibers and optimized it. The optimization module was designed by using two scintillators and three WLS fibers and attaching a sensor to the end of the WLS fiber. Optimum combinations were obtained through the light collection efficiency and the light collection ratio between sensors depending on coupling materials and reflectors of scintillators, WLS fibers and sensors. The highest light collection efficiency and the light collection ratio between sensors were obtained in the combination of the epoxy (coupling materials)-diffuse reflector (scintillators)-specular reflector (WLS fibers).

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.595-603
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• 2018

This study was conducted to understand the growth of attached microbial community in small and medium streams of Gyeonggi-do and the removal efficiency of fluoride with changes in growth. The sites monitoring were carried out for 12 weeks at the P1 and P2(P1 is the point where the discharge water flows. P2 is the downstream point of about 2 km flow), and investigated the water quality and the biomass analysis of the attached microbial community. The growth of the attached microbial community increased up to the 7th investigation, and it was observed that detachment phenomenon occurred. Influencing factors about growth of the attached microbial community were flow rate, velocity, and organic material(T-N & T-P). Meanwhile, fluoride content of attached microbial community also tended to increase until the 7th investigation, and decrease from the 8th. It is assumed that fluoride content has also be reduced with the detachment phenomenon of the attached microbial community. It is expected that this will contribute to the evaluation and management of the use of attached microbial community as a means of stream management. The application of techniques using the attached microbial community should include basic investigation of factors that may affect the growth of the attached microbial community and replacement of the attachment plate according to the time of removal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.769-771
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• 2003

고분산성을 이루는 물질들이 석영(quartz)을 바탕물질로 하여 기계-화학적 반응 기술을 이용하여 제작하였다. 반응의 처리 조건과 이후의 응용에 따라서 기계-화학적 반응을 이용하여 제작한 물질은 자기 특성, 유전체 특성, 전기적 특성을 동시에 나타냈다. 부착성 복합물질의 특징을 고려하여 세그네토 마그네틱스(Segneto-magnetics)로 분류 제작된 자기-전기적 분말은 유전체재료 특성을 나타냈다. 특히, 석영 표면에 하나 또는 그 이상의 이질 화합물 층이 10∼50nm 두께로 합성되어, 자기ㆍ전기적 특성을 나타냈다.

• Journal of Conservation Science
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• v.16 s.16
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• pp.21-26
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• 2004

A lot of waterlogged shrouds and mummies have been found in tombs revered with lime of the Chosun Dynasty(1392-1910) of Korea. Shrouds were heavily polluted with greyish white material. Greyish white material, which adhered to shrouds excavated from tombs(16C and 17C), was submitted to FT-IR qualitative analysis and fatty acid analysis for cleaning. The results of the FT-IR qualitative analysis identified the main ingredient of the greyish white material as calcium salt of fatty acid, including a little of the fatty acids, lipids and proteins. Therefore the greyish white material fumed out adipocere which was formed from the degradation of the lipids in a dead body. From the fatty acid analysis, hydroxy fatty acids(10-Hydroxyhexadecanoic acid and 10-Hydroxyoctadecanoic acid), which were found in adipocere, were detected. The distribution of contents of fatty acids was also rimilar to that of adipocere which have a high proportion of palmitic acid of saturated fatty acid and a low proportion of oleic arid of unsaturated fatty acid. In view of the results of analyses, it was revealed that greyish white material adhered to shrouds was adipocere moved from a mummy.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.303-303
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• 2013

표면에 부착된 나노/마이크로 입자는 다양한 분야에서 오염물질로 작용한다. 특히 형상이 미세하고 공정 단계가 복잡한 반도체 및 디스플레이 등의 전자 소자 공정에서 미치는 영향이 크다. 따라서 입자상 오염물질의 제거에 관하여 상용화된 습식 세정 방법이 다양하게 존재하지만 표면 손상, 화학 반응, 부산물, 세정 효율 등 여러 가지 문제점이 있어 새로운 세정 방법이 요구된다. 이에 건식 세정 방법, 그 중에서도 입자의 충돌을 통해 제거하는 방법인 에어로졸 세정, 필렛 세정 등이 개발되었으나 마이크로 크기로 생성되는 입자로 인하여 형상의 손상이 크다. 따라서 본 연구에서는 나노 단위로 기체/고체 혼합물만 생성하여 세정하는 가스 클러스터 세정 방법을 이용하여 이러한 문제점을 해결하고자 하였다. 클러스터 세정 장비를 이용한 표면 처리는 충돌에 의한 제거에 기반한다. 따라서 생성 및 가속되는 클러스터로부터 대상으로 전달되는 운동량의 정도가 세정 특성에 영향을 미치며 이는 생성되는 클러스터의 크기에 종속적이다. 생성 클러스터의 크기 분포는 분사 거리, 유량, 분사 각도, 노즐 냉각 온도 등의 변수에 관한 함수이다. 따라서 본 연구에서는 $CO_2$ 클러스터를 이용한 세정 특성을 정의 및 제어하기 위하여 생성되는 클러스터 특성에 관하여 이론적, 수치 해석적, 실험적 연구를 수행하였다. 먼저, $CO_2$의 물리적 특성 및 이를 이용한 특정 크기 오염 물질을 제거하는데 요구되는 임계 클러스터 크기 계산을 이론적으로 구하였다. 이는 오염물질의 부착력과 클러스터의 운동량 전달에 의한 제거력의 비교를 통해 이루어졌다. 두 번째로 클러스터 크기분포를 수치 해석적으로 예측하기 위하여 각 조건에 대하여 유동해석을 수행하고 이를 통해 구해진 노즐 내 기체의 냉각 속도를 GDE (General Dynamic Equation) 계산에 대입하여 구하였다. 마지막으로 PBMS(Particle Beam Mass Spectrometer)를 이용하여 실험적으로 클러스터 크기분포를 각 조건에 대하여 구할 수 있었다. 또한 크기 분포 경향에 대한 간접적 확인을 위하여 포토레지스트가 코팅된 웨이퍼에 클러스터의 충격으로 생성된 크레이터 크기의 경향을 분석하였다. 이와 같은 방법에 의하여 생성되는 클러스터는 노즐의 유량 증가, 온도 상승에 각각 비례하여 작아지는 것을 확인할 수 있었다.

• Journal of dental hygiene science
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• v.12 no.2
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• pp.155-162
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• 2012

Somok, the heart wood of Caesalpinia sappan is used in traditional Chinese medicine. Adherence of S. mutans to the tooth surface can result in the formation of a dental plaque. This study was performed to investigate the antibacterial activity and bacterial adhesion of ethyl acetate extract from C. sappan against S. mutans ATCC 25175. The bacteria were cultured in brain heart infusion(BHI) broth, and then incubated under 5% $CO_2$ at $37^{\circ}C$ for 18~24 hours. The antimicrobial activity of the ethyl acetate extract of C. sappan was then examined using the paper disc methods and MIC. In addition, bacterial adherence to hydroxyapatite was also examined. The ethyl acetate extract was shown to produce inhibitory effects and had MIC values of 125 mg/ml against S. mutans ATCC 25175. The ethyl acetate extract inhibited adhesion of S. mutans to saliva coated-hydroxyapatite beads(S-HA). At 24 hr, the ethyl acetate extract significantly reduced the adherence of S. mutans to S-HA beads relative to the control. The isolated active substance was identified as brazilin($C_{16}H_{14}O_5$) by $^1H-NMR$ and $^{13}C-NMR$. Thus, the application of C. sappan can be considered a useful and practical method for the prevention of dental caries.

• Food Science of Animal Resources
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• v.26 no.2
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• pp.263-268
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• 2006

Probiotics including Lactobacillus acidophilus, refer to a group of nonpathogenic organisms that protect the human host against gastrointestinal(GI) infections by pathogenic bacteria such as Shiga toxin-producing E. coli(STEC). In the study, the inhibitory effects of STEC ATCC 43894 adhesion by L. acidophilus A4 was investigated on the HT-29 epithelial cells. Specific proteins regulated by cell Iysates of L. acidophilus A4 on STEC ATCC 43894 were also characterized by proteomic analysis. Both cell mass and Iysate of L. acidophilus A4 have exhibited the profound inhibitory activity on the HT-29 cells(about 1.5 log scale reduction). Two-dimensional gel electrophoresis(2-DE) revealed seven proteins that were up-regulated by cell Iysates of L. acidophilus A4 and three proteins that were down-regulated. In addition, three protein spots were only detected in the presence of cell Iysates. These results suggest that inhibitory effects of STEC adhesion by L. acidophilus may be due to the regulation of specific protein of STEC.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1300-1310
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• 1990

Naphthalene sublimation technique is employed to investigate the mass transfer processes from a square cylinder at various Reynolds numbers and various angles of attack. Distribution of the local mass transfer coefficients on each face of the cylinder changes dramatically with the angle of attack. Such variation of local mass transfer rates closely connected with the complex flow phenomena such as stagnation, acceleration, separation, reattachment and vortex shedding. The average Sherwood number has a minimum value at 12.deg.-13.deg., and a maximum value at a=20.deg.-25.deg. A comparison of present mass transfer measurement with other heat transfer measurements, using the heat/mass transfer analogy, shows good agreement in average transfer rates, same trend but notable differences in local values. Therefore, naphthalene sublimation technique can be adopted to explore heat transfer processes in the complex flow situations, which is considered to be hardly possible with the conventional heat transfer measurements.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.40-44
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• 1998

키토산은 키틴을 탈아세틸화시켜 제조한 물질로서, 우수한 항미생물성, 생분해성, 비독성 및 강한 이온흡착능을 지니고 있어 이러한 우수한 성질을 섬유에 응용하기 위하여 저분자화하여 가교제로서 섬유에 부착시키는 방법[1], 섬유고분자와의 블렌딩[2,3] 등 여러 방법이 연구되어 왔으나 제조비용과 공정상의 단점 둥으로 사용에 제한이 따르고 있다.(중략)