• 대한미생물학회지
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• 제14권1호
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• pp.79-87
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• 1979

Newcastle병(病) 바이러스(L-NDV)가 ICR 마우스의 세포성(細胞性), 체액성(體液性) 면역반응(免疫反應)에 미치는 영향(影響)을 알아보기 위(爲)하여 2-NDV($10^6$EID/mouse)를 SRBC($10^6$EID_{50}/mouse)로 면역(免疫)하기 전후(前後) 또는 동시(同時)에 미정맥내(尾靜脈內)로 감염(感染)시키고 면역(免疫) 4일(日)에 SRBC($10^8$세포/mouse)를 challenge하여 24시간후(時間後)에 족척종창반응(足蹠腫脹反應)을 검사(檢査)하였으며, 동시(同時)에 비장세포(脾臟細胞)의 로젤형성능(形成能), 말초순환(末梢循環) 혈액내(血液內)의 임파구(淋巴球)의 수(數), 그리고 SRBC에 대(對)한 응집항체가(凝集抗體價) 및 용혈항체가(溶血抗體價)를 측정(測定)하였다. 한편 NDV 감염(感染)으로 인(因)한 면역반응(免疫反應) 억제기전(抑制機轉)을 구명(究明)하기 위(爲)하여 L-NDV를 가온(加溫) 불활화(不活化)하거나(H-NDV), 자외선(紫外線)에 조사(照射)시켜(UV-NDV) 마우스에 투여(投與)하거나, L-NDV로 유도(誘導)한 마우스조제(粗製) interferon(C-IF)을 투여(投與)하여 발현(發現)되는 반응(反應)을 측정(測定), 비교(比較)하여 다음과 같은 결과(結果)를 얻었다. 족척종창반응(足蹠腫脹反應)을 SRBC로 면역전(免疫前) 오는 면역후(免疫後)에 L-NDV를 접종(接種)한 군(群)에서 모두 억제(抑制)되었으며 그 억제정도(抑制程度)는 바이러스 감염(感染)과 항원주사(抗原注射)와의 간격(間隔)이 길면 길수록 심(甚)하였다. 그러나 UV-NDV나 H-NDV를 접종(接種)한 군(群)에서의 족척종창반응(足蹠腫脹反應)은 대조군(對照群)에 비(比)하여 대체적(大體的)으로 경미(輕微)하거나 전혀 억제(抑制)가 인지(認知)되지 않았다. 한편 C-IF나 C-IF를 가온불활화(加溫不活化)한 C-IFh를 투여(投與)한 군(群)에서의 족척종창(足蹠腫脹)은 정도(程度)의 차이(差異)는 있으나 대조군(對照群)에 비(比)하여 현저(顯著)히 감소(減少)되었다. 비장세포(脾臟細胞)의 로젤형성율(形成率)은 바이러스 감염(感染)으로 현저(顯著)히 감소(減少)되었는데 그 감소(減少)의 정도(程度)는 면역전(免役前) 또는 면역(免疫)과 동시(同時)에 바이러스를 접종(接種)한 군(群)에서 면역후(免疫後) 바이러스를 감염(感染)시킨 군(群)보다 심(甚)하였다. 한편 UV-NDV나 H-NDV를 접종(接種)한 군(群)에서 비장세포(脾臟細胞)의 로젤형성률(形成率)은 L-NDV 접종군(接種群)에 비(比)하여 약간(若干) 경미(輕微)한 감소(減少)를 보이거나 또는 비슷한 양상(樣相)을 보여 대조군(對照群)보다는 현저(顯著)히 억제(抑制)된 결과(結果)를 보였다. 또한 마우스에 C-IF를 투여(投與)하면 비장세포(脾臟細胞)의 로젤형성률(形成率)은 억제(抑制)되었으나 C-IFh를 투여(投與)하면 오히려 로젤형성률(形成率)이 증가(增加)되었다. 체액성면역반응(體液性免疫反應)은 면역전(免疫前) 24 및 48시간(時間)에 L-NDV를 접종(接種)한 군(群)에서는 현저(顯著)히 억제(抑制)되었으나, 면역전(免疫前) 9시간(時間), 면역(免疫)과 동시(同時) 또는 면역후(免疫後)에 L-NDV를 접종(接種)한 대조군(對照群)과 유의(有意)한 차이(差異)를 보이지 않았다. 순환혈액내(循環血液內) 임파구수(淋巴球數)는 면역전(免疫前) 48 또는 24시간(時間)에 L-NDV를 접종(接種)하면 대조군(對照群)에 비(比)하여 현저(顯著)히 감소(減少)되었으나, 면역전(免疫前) 9시간(時間) 또는 면역(免疫)과 동시(同時)에 L-NDV를 접종(接種)하면 오히려 그 수(數)가 증가(增加)되었다. 이상(以上)의 실험결과(實驗結果) SRBC에 대(對)한 세포성(細胞性) 면역반응(免疫反應)의 억제(抑制)는 NDV가 afferent limb과 efferent limb를 모두 억제(抑制)하여 야기(惹起)되는 체액성(體液性) 면역반응(免疫反應)의 억제(抑制)는 NDV가 afferent limb만을 억제(抑制)하여 일어남을 알 수 있다. 또한 NDV 감염(感染)으로 인(因)한 면역반응억제(免疫反應抑制)는 interferon과 바이러스의 직접적(直接的)인 작용(作用)에 기인(基因)됨을 강력(强力)히 시사(示唆)한다.

• 한국축산식품학회지
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• 제36권4호
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• pp.469-475
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• 2016

This study examined the relationship between NaCl sensitivity and stress response of Listeria monocytogenes. Nine strains of L. monocytogenes (NCCP10805, NCCP10806, NCCP10807, NCCP10808, NCCP10809, NCCP10810, NCCP10811, NCCP10920 and NCCP 10943) were exposed to 0%, 1%, 2% and 4% NaCl, and then incubated at 60℃ for 60 min to select strains that were heat-sensitized (HS) and non-sensitized (NS) by NaCl exposure. After heat challenge, L. monocytogenes strains were categorized as HS (NCCP 10805, NCCP10806, NCCP10807, NCCP10810, NCCP10811 and NCCP10920) or NS (NCCP10808, NCCP10809 and NCCP10943). Total mRNA was extracted from a HS strain (NCCP10811) and two NS strains (NCCP10808 and NCCP10809), and then cDNA was prepared to analyze the expression of genes (inlA, inlB, opuC, betL, gbuB, osmC and ctc) that may be altered in response to NaCl stress, by qRT-PCR. The expression levels of two invasion-related genes (inlA and inlB) and two stress response genes (opuC and ctc) were increased (p<0.05) in NS strains after NaCl exposure in an NaCl concentration-dependent manner. However, only betL expression was increased (p<0.05) in the HS strains. These results indicate that the effect of NaCl on heat sensitization of L. monocytogenes is strain dependent and that opuC and ctc may prevent NS L. monocytogenes strains from being heat sensitized by NaCl. Moreover, NaCl also increases the expression of invasion-related genes (inlA and inlB).

• 대한미생물학회지
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• 제5권1호
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• pp.41-48
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• 1970

In order to assay one lot of the potency of tuberculin for intradermic use, four guinea pigs sensitized with heat killed M. tuberculosis were used by the method originally of the Agriculture Research Service Center(A. R. S.) and Bureau of Animal. Industry(B. A. I.) in the United. States of America in which guinea pigs were used on 21st day after sensitization. There is doubt whether the guinea pigs are sensitized or not. Therefore, this study has taken the method of Middle Brook-Dubos hemagglutination test, and observed the humoral hemagglutinating antibody in the blood. The results obtained are as follows. 1. The maximum titer of hemagglutinating antibody was demonstrated 30days after sensitizing the guinea pigs with killed tubercle bacilli. The maximum titer was continued for a period of 45 days and thereafter declined gradually. 2. The swelling and redness of the region of the sensitized guinea pigs was shown to be reached to the maximum size within 24 hours after intradermal inoculation with HCSM tuberculin and gradually reduced 96 hours after inoculation. The swelling and redness could not be detected by macro-observation after 14 days.

• 열처리공학회지
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• 제21권3호
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• pp.150-156
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• 2008

The effects of austenitizing temperature in a range of $1000{\sim}1150^{\circ}C$ on the corrosion resistance in 420J2 stainless steel tempered at $150^{\circ}C$ were investigated by an electrochemical uniform corrosion test in a solution of 0.5M $H_2S0_4$. Pitting test and DL-EPR test for intergranular corrosion were carried out in a solution of 3.5% NaCl and 0.5M $H_2S0_4$ + 0.01 M KSCN respectively. In uniform corrosion test, specimens austenitized below $1100^{\circ}C$ showed similar corrosion current density and passive current density, whereas specimens austenitized at $1150^{\circ}C$ showed a little higher values. Pitting potential slightly increased with an increase of austenitizing temperature. The degree of sensitization, DOS, also slightly increased with an increase of austenitizing temperature, reaching the highest degree at $1150^{\circ}C$. It was expected that the increase of DOS was due to the larger grain size rather than the dissolved precipitates in the matrix.

• Corrosion Science and Technology
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• 제11권5호
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• pp.196-204
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• 2012

Corrosion failure of petrochemical facilities is one of the difficulties in maintenance, since operating conditions of crude oil production, storage, and refinement are very aggressive. UNS N08810, which has been used for crude oil transportation pipes and storage tanks in petrochemical industries, shows good resistance to general corrosion and localized corrosion in several environments. Among its environments, UNS N08810 showed better corrosion resistance in fuel gas containing sulfuric acid and phosphoric acid and sulfur. However, ductility and toughness at high temperature over about $500^{\circ}C$ were greatly reduced due to microstructural change. In general, welding process is the representative method to join the parts in industrial components. Because the alloy by welding can be sensitized and corroded, the manufacturing process should be controlled. In this work, UNS N08810 was used and heat treatment conditions including solution and stabilization treatments were controlled. Oxalic acid etch test by ASTM A262 Practice A was done to evaluate the qualitative sensitization in room temperature. Huey test by ASTM A262 Practice C was done to evaluate the intergranular corrosion rate in boiling 65% $HNO_3$ solution. Also, the microstructure by thermal history was analyzed. Experimental alloy showed high intergranular corrosion rate and its corrosion mechanism was elucidated.

• Corrosion Science and Technology
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• 제9권6호
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• pp.294-299
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• 2010

Two types of welding methods were performed on austenitic 304 stainless steel: laser welding and TIG welding. The differences of the corrosion characteristics of the welded zones from the two welding methods were investigated with electrochemical methods, such as measurement of the corrosion potential, polarization curves, cyclic voltammogram, etc. The vickers hardness of all laser-welded zones (WM:Weld Metal, HAZ:Heat Affected Zone, BM:Base Metal) was relatively higher while their corrosion current densities exhibited a comparatively lower value than those which were TIG welded. In particular, the corrosion current density of the TIG-welded HAZ had the highest value among all other welding zones, which suggests that chromium depletion due to the formation of chromium carbide occurs in the HAZ, which is in the sensitization temperature range, thus it can easily be corroded with an active anode. Intergrenular corrosion was also observed at the TIG-welded HAZ and WM zones. Consequently, we can see that corrosion resistance of all austenitic 304 stainless steel welding zones can be improved via the use of laser welding.

• Corrosion Science and Technology
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• 제15권5호
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• pp.226-236
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• 2016

316L stainless steels have been widely used in many engineering fields, because of their high corrosion resistance and good mechanical properties. However, welding or aging treatment may induce intergranular corrosion and stress corrosion cracking etc. Since these types of corrosion are closely related to the formation of chromium carbide in grain boundaries, the alloys are controlled by methods such as the lowering of carbon content, solution heat treatment. This work focused on the intergranular corrosion mechanism of slightly-sensitized and Ultrasonic Nano-crystal Surface Modification (UNSM)-treated 316L stainless steel. Samples were sensitized for 1, 5, and 48 hours at $650^{\circ}C$ in $N_2$ gas atmosphere. Subsequently UNSM treatments were carried out on the surface of the samples. The results were discussed on the basis of the sensitization by chromium carbide and carbon segregation, the residual stress and grain refinement. Even though chromium carbide was not precipitated, the intergranular corrosion rate of 316L stainless steel was drastically increased with aging time, and it was confirmed that the increased intergranular corrosion rate of slightly-sensitized (not carbide formed) 316L stainless steel was due to the carbon segregation along the grain boundaries. However, UNSM treatment improved the intergranular corrosion resistance of aged stainless steels, and its improvement was due to the reduction of carbon segregation and the grain refinement of the outer surface, including the introduction of compressive residual stress.

• Corrosion Science and Technology
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• 제19권6호
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• pp.296-301
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• 2020

Failure analysis on the welded type 304 pipe used for cooling water piping in the district heating primary side was conducted. Inorganic elements and bacteria in the cooling water and in corrosion products were analyzed, and the weldment was inspected by microscopy and a sensitization test. Corrosion damages were observed in the heat-affected zone, on weld defects such as incomplete fusion or excessive penetration caused by improper welding, or/and at the 6 o'clock position along the pipe axial direction. However, the level of concentration of chloride in the cooling water as low as 80 ppm has been reported to be not enough for even a sensitized type 304 steel, meaning that the additional corrosive factor was required for these corrosion damages. The factor leading to these corrosion damages was drawn to be the metabolisms of the types of bacteria, which is proved by the detection of proton, sulfur containing species, biofilms, and both bacteria and corrosion product analyses.

• 한국표면공학회지
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• 제49권6호
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• pp.530-538
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• 2016

There is a close relationship between the performance and the heat generation of the electronic device. Heat generation causes a significant degradation of the durability and/or efficiency of the device. It is necessary to have an effective method to release the generated heat. Based on demands of the printed circuit board (PCB) manufacturing, it is necessary to develop a robust and reliable plating technique for substrates with high thermal conductivity, such as alumina ($Al_2O_3$), aluminium nitride (AlN), and silicon nitride ($Si_3N_4$). In this study, the plating of metal layers on an insulating silicon nitride ($Si_3N_4$) ceramic substrate was developed. We formed a Pd-$TiO_2$ adhesion layer and used APTES(3-Aminopropyltriethoxysilane) to form OH groups on the surface and adhere the metal layer on the insulating $Si_3N_4$ substrate. We used an electroless Ni plating without sensitization/activation process, as Pd particles were nucleated on the $TiO_2$ layer. The electrical resistivity of Ni and Cu layers is $7.27{\times}10^{-5}$ and $1.32{\times}10^{-6}ohm-cm$ by 4 point prober, respectively. The adhesion strength is 2.506 N by scratch test.

• Journal of Advanced Marine Engineering and Technology
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• 제35권6호
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• pp.802-808
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• 2011

극저온 온도 구조 재료의 중요한 기계적 성질 중 하나는 파괴 인성이다. 파괴 인성 시험 방법의 규격화에 대한 연구는 극저온 구조 요소의 개발과 함께 매우 중요한 문제가 되고 있다. 특히 용접부의 경우 극저온 환경 하에서 사용할 때 불안정파괴를 유발할 수 있기 때문에 용접부의 각 미세조직에 따른 기계적 성질 평가가 중요하다. 본 연구에서는 STS-316L 모재와 용접재를 대상으로 액체질소(77K), 액체헬륨(4K), 293K 온도에서 제하컴플라이언스법과 예민화 열처리한 소형화된 시험편 대상으로 파괴인성평가 실험을 수행하였다.