• 한국물환경학회지
• /
• 제22권4호
• /
• pp.590-598
• /
• 2006

In-situ Air sparging (IAS) is a groundwater remediation technique, in which organic contaminants volatilize into air form the saturated to vadose zone. This study was carried out to evaluate the effect of sludge and soil microbial community structure on air sparging of Total Petroleum Hydrocarbons (TPH) contaminated groundwater soils. In the laboratory, diesel (10,000 mg TPH/kg) contaminated saturated soil. The Air was injected in intermittent (Q=1500 mL/min, 10 minute injection and 10 minute idle) modes. For Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis of eubacterial communities in sludge of wastewater treatment plants and soil of experiment site, the 16S rDNA was amplified by Polymerase Chain Reaction (PCR) from the sludge and the soil. The obtained 16S rDNA fragments were digested with Msp I and separated by electrophoresis gel. We found various sequence types for experiment with sludge soil samples that were closely related to Agrococcus, Flavobacterium, Thermoanaerobacter, Flexibacter and Shewanella, etc, in the clone library. The results of the present study suggests that T-RFLP method may be applied as a useful tool for the monitoring in the TPH contaminated soil the fate of microorganisms in natural microbial community.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.102-102
• /
• 2016

Water, which is most abundant in Earth surface and very closely related to all forms of living organisms, has a simple molecular structure but exhibits very unique physical and chemical properties. Even though tremendous effort has been paid to understand this nature's core substance, there amazingly still lefts much room for scientist to explore its novel behaviors. Especially, as the scale goes down to nano-regime, water shows extraordinary properties that are not observable in bulk state. One of such interesting features is the formation of nanoscale bubbles showing unusual long-term stability. Nanobubbles can be spontaneously formed in water on hydrophobic surface or by decompression of gas-saturated liquid. In addition, the nanobubbles can be generated during electrochemical reaction at normal hydrogen electrode (NHE), which possibly distorts the standard reduction potential at NHE as the surface nanobubble screens the reaction with electrolyte solution. However, the real-time evolution of these nanobubbles has been hardly studied owing to the lack of proper imaging tools in liquid phase at nanoscale. Here we demonstrate, for the first time, that the behaviors of nanobubbles can be visualized by in situ transmission electron microscope (TEM), utilizing graphene as liquid cell membrane. The results indicate that there is a critical radius that determines the long-term stability of nanobubbles. In addition, we find two different pathways of nanobubble growth: i) Ostwald ripening of large and small nanobubbles and ii) coalescence of similar-sized nanobubbles. We also observe that the nucleation and growth of nanoparticles and the self-assembly of biomolecules are catalyzed at the nanobubble interface. Our finding is expected to provide a deeper insight to understand unusual chemical, biological and environmental phenomena where nanoscale gas-state is involved.

• 대한두경부종양학회지
• /
• 제16권1호
• /
• pp.14-19
• /
• 2000

Objectives: Epstein-Barr virus(EBV) is a B-lymphotrophic virus with a tumorigenic potential. EBV infection has been recognized as the main cause of nasopharyngeal carcinoma and Burkitt's lymphoma. Bcl-2 protein expression is known to be up-regulated by the EBV-latency associated antigen latent membrane protein(LMP). The aim of this study was to determine the incidence of EBV in squamous cell carcinomas of the larynx and the relationship between the presence of EBV and bcl-2 expression. Patients and Methods: From January 1994 to December 1977, 35 patients with primary squamous cell carcinoma of the larynx were studied. EBV genome DNA was surveyed by polymerase chain reaction(PCR) assay and then compared the results of in situ hybridization(ISH) for EBER1 using digoxigenin-tailed oligonucleotide probe. The expression of bcl-2 protein was studied by immunohistochemistry(IHC) using bcl-2 monoclonal antibody. Results: By PCR, EBV genome was detected in 22 of 35(62.9%) squamous cell carcinomas of the larynx. Nineteen of 35 cases(54.3%) showed a positive nuclear staining for EBER1 in tumor cells by ISH. Three cases showed positivity in inflammatory cells by ISH and one of them showed a positive staining of both tumor cells and inflammatory cells. Eighteen of 32 specimens(62.5%) were positive for bcl-2 protein. There was no significant correlations between the presence of EBV DNA and bcl-2 expression. Conclusions: It could be concluded that high incidence of EBV in the laryngeal cancer tissue may indicate a probable role of EBV in the development of laryngeal carcinoma.

• 한국분말재료학회지
• /
• 제9권6호
• /
• pp.441-448
• /
• 2002

Dispersions of non-soluble ceramic particles in a metallic matrix can enhance the strength and heat resistance of materials. With the advent of mechanical alloying it became possible to put the theoretical concept into practice by incorporating very fine particles in a flirty uniform distribution into often oxidation- and corrosion- resistant metal matrices. e.g. superalloys. The present paper will give an overview about the mechanical alloying technique as a dry, high energy ball milling process for producing composite metal powders with a fine controlled microstructure. The common way is milling of a mixture of metallic and nonmetallic powders (e.g. oxides. carbides, nitrides, borides) in a high energy ball mill. The heavy mechanical deformation during milling causes also fracture of the ceramic particles to be distributed homogeneously by further milling. The mechanisms of the process are described. To obtain a homogeneous distribution of nano-sized dispersoids in a more ductile matrix (e.g. aluminium-or copper based alloys) a reaction milling is suitable. Dispersoid can be formed in a solid state reaction by introducing materials that react with the matrix either during milling or during a subsequent heat treatment. The pre-conditions for obtaining high quality materials, which require a homogeneous distribution of small dis-persoids, are: milling behaviour of the ductile phase (Al, Cu) will be improved by the additives (e.g. graphite), homogeneous introduction of the additives into the granules is possible and the additive reacts with the matrix or an alloying element to form hard particles that are inert with respect to the matrix also at elevated temperatures. The mechanism of the in-situ formation of dispersoids is described using copper-based alloys as an example. A comparison between the in-situ formation of dispersoids (TiC) in the copper matrix and the milling of Cu-TiC mixtures is given with respect to the microstructure and properties, obtained.

• 공업화학
• /
• 제3권3호
• /
• pp.499-506
• /
• 1992

모노머의 반응성비가 각각 $r_1=0.53$, $r_2=0.44$반응인 styrene과 GMA(glycidyl methacrylate)를 일정 몰비로 반응시켜서 styrene과 GMA의 공중합체인 PGS를 합성한 후, 에틸렌 디아민을 반응시켜서 공중합체내에 아민기를 도입시켰다. 아민기가 도입된 중합체인 NPGS는 PGMA와 블렌드시에 DSC분석 결과, 단일 Tg를 나타내므로 두 폴리머는 상용 성이 있다는 것이 관찰되었다. 이 NPGS-PGMA의 블렌드를 PS-PGMA블렌드물에 일정무게비로 첨가하여서 이에 따른 상용성의 변화를 관찰하였다. 즉, 비상용성인 PS-PGMA블렌드에, 에폭시기와 아민기와의 화학적 반응에 의하여 상용성을 나타내는 NPGS-PGMA블렌드의 첨가에 따른 상용성의 향상을 DSC분석을 통한 Tg변화와 SEM (Scanning electron microscopy)측정에 의한 morphology변화를 통하여서 관찰하였다. 측정 결과, PS-PGMA 블렌드는 NPGS-PGMA 블렌드가 첨가됨에 따라 Tg변화를 나타내었고, PGMA의 PS내에서의 분산은 향상되었다. 따라서, NPGS-PGMA의 블렌드는 PS-PGMA블렌드의 상용성을 향상시키는 상용화제로서의 작용을 하였다.

• Bulletin of the Korean Chemical Society
• /
• 제32권7호
• /
• pp.2351-2357
• /
• 2011

Three new metal-organic copper(II) complexes, $[Cu(H_2PZTC)_2]_n{\cdot}2nH_2O$ (1), $[Cu(HPZTC){\cdot}2H_2O]_n{\cdot}2nH_2O$ (2), and $Cu_2[(PZHD)(OH)(H_2O)_2]_n$ (3) ($H_3PZTC$ = pyrazine-2,3,5-tricarboxylic acid, $PZHD^{3-}$ = 2-hydroxypyrazine-3,5-dicarboxylate), have been synthesized from $Cu(II)/H_3PZTC$ system under different synthetic conditions, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. In complexes 1 and 2, $H_3PZTC$ ligands loose one and two protons, which were transformed into $H_2PZTC^-$ anion and $HPZTC^{2-}$ dianion under different preparation condition, respectively. Furthermore, two ligands coordinate with Cu(II) cations in different modes, leading to the formation of the different chain structures. In complex 3, $H_3PZTC$ ligand was converted into a new ligand-PZHD by in situ decarboxylation and hydroxylation under a higher pH value than that for complexes 1 and 2. PZHD ligands link the Cu(II) cations to form a 2D layer structure. These results demonstrate that the preparation conditions, including pH value and reaction temperature etc, play an important role in the construction of complexes based on $H_3PZTC$ ligand.

• 한국수산과학회지
• /
• 제54권5호
• /
• pp.660-667
• /
• 2021

In recent years, myxosporean infection from the cultured olive flounders Paralichthys olivaceus, have been frequently observed in Jeju island, South Korea. This study aimed to compare histopathological and molecular-biological methods of examining myxosporean infection from these flounders. Samples were obtained from affected individuals exhibiting emaciation or abdominal distention and a polymerase chain reaction (PCR) indicative of Parvicapsular anisocaudata, Enteromyxum leei and Kudoa septempunctata were initiated. Histopathological examination were conducted with H&E stained tissue sections, and then in-situ hybridization (ISH) reaction were processed with selected sections using P. anisocaudata, E. leei, K. septempunctata and Scuticociliate probes. Renal and intestinal tissue degeneration were common symptoms associated with all samples. Sever glomerular and renal tubular degeneration were evident, as were intestinal epithelial desquamation and spore formation in the epithelial cells. The results of conventional PCR analysis and ISH reactions revealed differences, and we suspect that various microparasites may have been associated with the symptoms manifested.

• 한국재료학회지
• /
• 제16권5호
• /
• pp.323-328
• /
• 2006

In situ electrical conductivity measurements on $V_2O_5WO_3/TiO_2$ catalysts were carried out at between 100 and $300^{\circ}C$ under pure oxygen, NO and $NH_3$ to investigate the reaction mechanism for ammonia SCR (selective catalytic reduction) de NOX. The electrical conductivity of catalysts changed irregularly with supply of NO. It was, however, found that the electrical conductivity change with ammonia supply was regular and the increase of electrical conductivity was mainly caused by reduction of the labile surface oxygen. The electrical conductivity change of catalysts showed close relationship with the conversion rate of NOx. Variation of conversion rate in atmosphere without gaseous oxygen also showed that labile lattice oxygen is indispensable in the initial stage of the de NOx reaction. These results suggest that liable lattice oxygen acts decisive role in the de NOx mechanism. They also support that de NOx reaction occurs through the Eley?Rideal type mechanism. The amount of labile oxygen can be estimated from the measurement of electrical conductivity change for catalysts with ammonia supply. This suggests that measurement of the change can be used as a measure of the de NOx performance.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.261-267
• /
• 2011

The test fit has commonly used for the evaluation of the railbed condition, and indirect methods by using the compressional wave are also studied. the direct evaluation method by penetration test has not been studied. For the measurement of in-situ cone tip resistance of the railbed with minimizing the disturbance of the upper railbed. the cone penetrometer with the helical type outer rod(CPH) was developed. The outer rod, which has helical screw, is penetrated through the gravel layer and provides the reaction force for cone penetration testing. the cone tip resistances are measured by the mini cone penetrometer, where diameter is 15mm. For the developing the mini cone, strain gauge installation, circuit configuration, penetration rates and calibration process are considered. For the easy penetration of the screw rod in the field, the reaction force stepping plate and guide column are arranged. The screw rod are penetrated through the gravel layer. And the mini cone was pushed into the subgrade railbed at the penetration rate of 1mm/sec. The penetration test shows that the cone tip resistance increases along the depth. In addition, the subgrade condition is evaluated. This study demonstrates that the CPH may be effectively used for the evaluation of subgrade method any damage of the gravel layer.

• Progress in Superconductivity
• /
• 제14권2호
• /
• pp.116-121
• /
• 2012

Effect of mixed gas and additional Mg powder in an annealing process of the $MgB_2$ is investigated. Four different type of samples were prepared, each in different annealing environment of Ar, $Ar+4%H_2$, Ar with Mg powder and $Ar+4%H_2$ with Mg powder. Different annealing environment did not affect the electron-phonon interaction which is reflected from the same superconducting transition of 36.6 K for all samples. The reducing effect of hydrogen is clearly depicted from the presence of excess Mg in sample synthesized in $Ar+4%H_2$ gas implying the reduced rate of reaction between Mg and B. This has manifested itself in terms of slightly increased high-field critical current density of the sample. In contrast, the sample synthesized in $Ar+4%H_2$ with Mg powder, has shown overall enhancement in the superconducting properties as presented by higher diamagnetic saturation and critical current density.