• 전기화학회지
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• 제3권3호
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• pp.162-168
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• 2000

전기주석도금용 PSA(Phenolsulfonic Acid Bath)계 전기주석 도금액은 장기간 사용하면 노화되어 도금 전류밀도 범위 축소 및 표면특성 열화현상이 일어나게 된다. 본 연구에서는 도금액 노화 현상의 원인을 축적된 phenolsulfonate농도 증가의 관점에서 조사하였다. 동전위와 정전위 분극실험 결과에서는, phenolsulfonate축적농도 증가에 따른 도금액의 노화 정도가 증가함에 따라 음극분극 초기에 나타나는 한계전류밀도가 점차 낮아지는 현상이 나타났다. Sodium phenolsulfonate를 첨가하여 phenolsulfonate끼 농도만을 조절한 도금액에서도 노화된 도금액과 거의 비슷한 분극 특성이 나타남으로써 도금액 노화의 원인이 축적된 phenolsulfonate임을 간접적으로 확인할 수 있었다. 또한 도금액의 온도가 증가할수록 한계전류밀도가 뚜렷하게 나타나지 않고 도금액 노화에 따른 영향이 적어져서 도금액의 노화는 물질이동과 같은 thermally-activated process의 제약에 의한 것이며, phenolsulfonate가 축적되면서 주석 이온의 mobility를 감소시키고, 따라서 정상적인 도금 반응이 억제되는 것으로 판단된다.

• International Journal of Oral Biology
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• 제31권4호
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• pp.141-148
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• 2006

The effects of adenosine triphosphate(ATP) on salivary glands have been recognized since 1982. The presence of purinergic recepetors(P2Rs) that mediate the effects of ATP in various tissues, including parotid and submandibular salivary gland, has been supported by the cloning of receptor cDNAs and the expression of the receptor proteins. P2Rs have many subtypes, and the activation of these receptor subtypes increase intracellular $Ca^{2+}$, a key ion in the regulation of the secretion in the salivary gland. The apical pores of taste buds in circumvallate and foliate papillae are surrounded by the saliva from von Ebner salivary gland(vEG). Thus, it is important how the secretion of vEG is controlled. This study was designed to elucidate the roles of P2Rs on salivary secretion of vEG. Male Sprague-Dawley rats (about 200 g) were used for this experiment. vEG-rich tissues were obtained from dissecting $500-1,000\;{\mu}m$ thick posterior tongue slices under stereomicroscope view. P2Rs mRNA in vEG acinar cells were identified with RT-PCR. To observe the change in intracellular $Ca^{2+}$ activity, we employed $Ca^{2+}-ion$ specific fluorescence analysis with fura-2. Single acinar cells and cell clusters were isolated by a sequential trypsin/collagenase treatment and were loaded with $10\;{\mu}M$ fura -2 AM for 60 minutes at room temperature. Several agonists and antagonists were used to test a receptor specificity. RT-PCR revealed that the mRNAs of $P2X_4$, $P2Y_1$, $P2Y_2$ and $P2Y_3$ are expressed in vEG acinar cells. The intracellular calcium activity was increased in response to $10\;{\mu}M$ ATP, a P2Rs agonist, and 2-MeSATP, a $P2Y_1$ and $P2Y_2R$ agonist. However, $300\;{\mu}M\;{\alpha}{\beta}-MeATP$, a $P2X_1$ and $P2X_3R$ agonist, did not elicit the response. The responses elicited by $10\;{\mu}M$ ATP and UTP, a $P2Y_2R$ agonists, were maintained when extracellular calcium was removed. $10\;{\mu}M$ suramin, a P2XR antagonist, and reactive blue 2, a P2YR antagonist, partially blocked ATP-induced response. However, when extracellular calciums were removed, suramin did not abolish the responses elicited by ATP. These results suggest that P2Rs play an important role in salivary secretion of vEG acinar cells and the effects of ATP on vEG salivary secretion may be mediated by $P2X_4$, $P2Y_1$, $P2Y_2$, and/or $P2Y_3$.

• Tuberculosis and Respiratory Diseases
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• 제71권1호
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• pp.30-36
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• 2011

Background: Pneumonia is commonly seen in outpatient clinics. it is widely known as the most common cause of death from infectious disease. Pneumonia has been diagnosed by its typical symptoms, chest X-ray and blood tests. However, both chest X-rays and blood tests have limitations in diagnosis. Thus primary care clinicians usually have been constrained due to a lack of adequate diagnostic tools. Vibration response imaging (VRI) is a newly emerging diagnostic modality, and its procedure is non-invasive, radiation-free, and easy to handle. This study was designed to evaluate the diagnostic usefulness of the VRI test among pneumonia patients and to consider its correlation with other conventional tests such as Chest X-ray, laboratory tests and clinical symptoms. Methods: VRI was performed in 46 patients diagnosed with pneumonia in Konkuk University Medical Center. VRI was assessed in a private and quiet room twice: before and after the treatment. Sensors for VRI were placed on a patient's back at regular intervals; they detected pulmonary vibration energy produced when respiration occurred and presented as specific images. Any modifications either in chest X-ray, C-reactive protein (CRP), white blood cell count (WBC) or body temperature were compared with changes in VRI image during a given time course. Results: VRI, chest X-ray and CRP scores were significantly improved after treatment. Correlation between VRI and other tests was not clearly indicated among all patients. But relatively severe pneumonia patients showed correlations between VRI and chest X-ray, as well as between VRI and CRP. Conclusion: This study demonstrates that VRI can be safely applied to patients with pneumonia.

• 혜화의학회지
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• 제12권1호
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• pp.103-121
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• 2003

Human being can't live without nature, then the changes of nature affect human body. It means that human body has corresponding changes to the KI(vital energy) of nature. There is a stream of changes in human body which circulate mysteriously and punctually by the laws of nature. If this stream of changes fits into human's life style, it would be most effective. It has a certain mode continuously. So if a person has a habit fitting into it, he will get the healthiest body. Then the researcher tries to explain the changes in human body by the time, mainly focused on within 24 hours. it is showing not only the oriental view, but also the western's. The researcher can find the coincidence as followings. At In-Si(3-5 am), the body function and the body temperature get to the bottom, therefore it's good for him to wake up and to run the vital energy. At Sa-Si(9-11 am), the patience on pain anxiety and the psychic concentration get to the top, he'd better start the work. At O-Si(11am-1pm), the heart energy has a vital move, then the blood concentration of Hb(hemoglobin) gets to the top. At Mi-Si(1-3 pm), the muscle strength, the squeeze, and the breathing rate increase. The reflex nerve sensitivity gets to the top. Creativity, observation, and working efficiency go high, so it's time to work hard. At Hae-Si(9pm-1am), the body function falls, sleeping is needed. At Chuck-Si(1-3 am), the cell spontaneity gets to the top, immune lymphocyte moves actively, and the blood concentration of growth hormone gets to the top. These are liver's work. In west, there has been active studies on how to reduce the side effect by using a person's bio-rhythm based on the 'time treatment', and how to reorganize the bio-rhythm by using the machine and the age resistance based on the 'bio-watch'. Though the 'time treatment' means something, the artificial resistance on bio-rhythm seems to give bad effects to human body. If a person lives by regimen of oriental medicine, he will maintain the healthiest body. Regimen is that human body follows the laws of nature, and moves its mysterious, Punctual and periodical changes.

• Journal of Advanced Marine Engineering and Technology
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• 제38권4호
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• pp.409-417
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• 2014

최근 수년 동안 유가의 현저한 상승으로 인하여 상선의 디젤 기관은 저질 중유를 주로 사용하게 되었다. 따라서 저질 중유의 사용 증가에 따른 디젤 기관의 연소실 배기가스 온도는 점차 상승하여 가혹한 부식 환경에 직면하게 되었다. 그 결과 연소실 주변의 모든 기관 부품들의 부식과 마모는 다른 기관 부품들에 비해서 심각하다. 그러므로 이들 부품들의 적절한 덧살 용접은 수명 연장을 위하여 경제적인 측면에서 매우 중요하다. 본 연구에서는 피스톤 크라운 재질로 통상 사용되는 단강에 4종류의 용접재료로 SMAW와 GTAW로 용접하였다. 실험은 모재, 열영향부 및 용접금속의 부식 특성을 35% 황산용액에서 부식전위, 양극분극 곡선, 사이클릭볼타모그램 및 임피던스 등의 전기화학적인 방법으로 하여 고찰하였다. Inconel 625, 718 용접재료의 경우 용접금속의 내식성이 가장 우수하였고, 모재의 내식성이 가장 좋지 않았으며, 반면에 1.25Cr-0.5Mo와 0.5Mo는 모재가 용접금속에 비해서 더 좋은 내식성을 나타내었다. 또한, 용접금속 중 Inconel 625가 가장 내식성이 우수하였으며, 그 다음으로 Inconel 718 용접재료로 나타났다. 경도 역시 용접금속이 상대적으로 모재, 열영향부에 비해서 높은 값을 나타내었다. 특히 Inconel 718 용접재료의 경우 다른 용접재료에 비하여 가장 높은 경도값을 나타내었다.

• 한국식품저장유통학회지
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• 제13권5호
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• pp.629-633
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• 2006

리기다소나무 잎추출물의 항균력을 조사한 결과, $100{\sim}250{\mu}g/mL$ 이상의 농도에서 뚜렷한 항균활성을 보였고, 광역의 병원성 및 부패성 미생물들에 대하여 항균활성을 나타내었다. 특히, 리기다소나무 알코올 추출물에서는 $100{\mu}g/mL$의 낮은 처리농도에서도 뚜렷한 항균력을 나타내었다. 또한 추출물의 농도가 증가함에 따라 미생물의 생육저해환의 직경도 커졌으며, 알코올추출물에서 좀 더 뚜렷한 항균력을 관찰할 수 있었다. 또한, 리기다소나무 잎추출물은 넓은 범위의 열 및 pH에서 안정성을 나타냈다. 따라서 리기다소나무 잎추출물의 항균물질은 항균활성이 높고, 항균 spectrum이 광범위 할뿐 아니라, 넓은 범위의 온도 및 pH에 안정하여 이상적인 천연 항균제로서의 개발가능성을 제시하였다. 아울러, 리기다소나무 잎추출물의 주요 항균작용기작은 미생물 세포막의 perturbation 기능에 기인한 것으로 사료되었다. 또한, fomalin 투여후 PRLE처리로 혈청내 formaldehyde의 분해가 촉진되어 제거비율이 증진되는 효과를 보였으며, formalin 투여로 인한 생체내 hemoglobin 생성비율도 짧은 시간내에 회복됨을 예측할 수 있었다.

• 한국식품저장유통학회지
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• 제15권3호
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• pp.377-384
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• 2008

복숭아의 보존기한 연장을 위한 품질 향상을 위한 방법으로 적숙기의 복숭아에 1 kGy의 감마선 조사를 실시한 다음, $4^{\circ}C$와 $25^{\circ}C$의 저장조건에서 복숭아의 일반적인 품질 특성 및 관능학적 품질 특성을 평가하였다. 연구 결과, 과실류에 대한 Codex 권장선량인 1 kGy 선량의 감마선 조사에서 복숭아의 품질변화는 나타나지지 않았으며 초기 오염미생물의 균수를 약 2 log 단위($10^2\;CFU/g$) 정도 감소시키는 제어 효과가 확인되었다. 감마선 조사 복숭아의 보존 실험에서, 감마선 조사된 복숭아는 $25^{\circ}C$의 조건에서는 약 1주, $4^{\circ}C$의 조건에서 약 6주 이상의 미생물학적 품질 안전성을 나타내었으며 위축률, 수분감소, 경도 등의 이화학적 품질에서도 개선효과가 확인되었다. 감마선 조사 직후에는 감마선 조사 복숭아와 비조사 시료간의 관능특성 차이는 관찰되지 않았으나, 보존기간이 경과함에 따라 감마선 조사시료의 선호도가 비조사 시료보다 더 증가함을 확인하였다. 따라서 감마선 조사와 냉장보존을 병용할 경우, 상온 1주 이하인 복숭아의 미생물학적 보존기한을 4주 이상으로 연장시킬 수 있을 것으로 사료되었다.

• 한국결정성장학회지
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• 제6권4호
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• pp.600-608
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• 1996

리튬 이온이 intercalation되어 스핀넬 구조를 이루고 있는 $Li_{x}Mn_{2}O_{4}(0.2{\leq}x{\leq}2.0)$의 구조적 특성을 X-선 회절분석과 Li/1M $LiClO_{4}$-propylene carbonate solution/$Li_{x}Mn_{2}O_{4}$ 전지에서 이들의 구조적 특징에 의한 전기화학적 특성을 연구하였다. $Li_{x}Mn_{2}O_{4}$의 전기화학적 특성에 대한 조성과 반응온도의 영향은 상전이 현상과, 결정 상수 측정과 열분석에 의하여 연구하였다. 산처리 후 $Li_{x}Mn_{2}O_{4}$는 거의 순수한 ${\lambda}-MnO_{2}$구조로 상전이 되었으며 이때 격자상수 $a_{c}$가 8.255에서 $8.031\;{\AA}$으로 수축되었다. $Li_{x}Mn_{2}O_{4}$의 조성 범위가 $0.2{\leq}x{\leq}0.6$일 때 격자상수 $8.255\;{\AA}$의 단일상을 나타내며 3.9~3.7 V의 전위 평탄 영역을 나타낸다.

• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.543-550
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• 2009

The single-crystal structure of largely ammonium-exchanged zeolite Y dehydrated at room temperature (293 K) and 1 ${\times}\;10^{-6}$ Torr. has been determined using synchrotron X-radiation in the cubic space group $Fd\overline{3}m\;(a=24.9639(2)\AA)$ at 294 K. The structure was refined to the final error index $R_1$ = 0.0429 with 926 reflections where $F_o>4\sigma(F_o)$; the composition (best integers) was identified as |$(NH_4)_{60}Na_{11}$|[$Si_{121}Al_{71}O_{384}$]-FAU. The 11 $Na^{+}$ ions per unit cell were found at three different crystallographic sites and 60 ${NH_4}^{+}$ ions were distributed over three sites. The 3 $Na^{+}$ ions were located at site I, the center of the hexagonal prism ($Na-O\;=\;2.842(5)\;\AA\;and\;O-Na-O\;=\;85.98(12)^{\circ}$). The 4 $Na^{+}$ and 22 ${NH_4}^{+}$ ions were found at site I' in the sodalite cavity opposite the double 6-rings, respectively ($Na-O\;=\;2.53(13)\;\AA,\;O-Na-O\;=\;99.9(7)^{\circ},\;N-O\;=\;2.762(11)\;\AA,\;and\;O-N-O =\;89.1(5)^{\circ}$). About 4 $Na^{+}$ ions occupied site II ($(Na-O\;=\;2.40(4)\;\AA\;and\;O-Na-O\;=\;108.9(3)^{\circ}$) and 29 ${NH_4}^{+}$ ions occupy site II ($N-O\;=\;2.824(9)\;\AA\;and\;O-N-O\;=\;87.3(3)^{\circ}$) opposite to the single 6-rings in the supercage. The remaining 9 ${NH_4}^{+}$ ions were distributed over site III' ($N-O\;=\;2.55(3),\;2.725(13)\;\AA\;and\;O-N-O\;=\;94.1(13),\;62.16(15),\;155.7(14)^{\circ}$).

• 농업과학연구
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• 제41권3호
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• pp.163-167
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• 2014

The average temperatures for year and winter season have been risen by $0.7{\circ}C$ and $1.4{\circ}C$, respectively, during the last 30 years. Recently abnormal climate phenomena occurred frequently results in severe loss of vegetable crops grown in Korea. Specially, Chinese cabbages grown in the southern area of Korea are often significantly affected by sudden cold waves during winter season before harvest. This experiment was conducted to find out a potential role of covering materials on the protection of frost damage of 'Bularm' chinese cabbage in the winter season. The lowest temperature was $-15.8^{\circ}C$ in non-covering, $-8.1^{\circ}C$ in the PE film covering and $-4.6^{\circ}C$ in the non-woven fabric covering with PE film, respectively. The cumulative times below $4.0^{\circ}C$ were 145.5 hours for the non-covering treatment, 94 hours in the PE film covering and 14.5 hours in the non-woven fabric covering with PE film, respectively. The symptoms of frost damage were severe at non-covering chinese cabbages compared to polyethylene film (PE) non-woven fabric with PE covering ones. Microscopic studies showed the normal anatomical structure of palisade and spongy tissue of cabbage leaves covered with non-woven fabric with PE film. Leaf cells, however, were slightly damaged in cabbages covered with PE film alone, and both palisade and spongy cells were were completely collapsed in uncovered cabbages. The result of this study suggests that chinese cabbages is required to be covered with non-woven fabric with PE film to minimize the frost damage by sudden cold wave below $-7^{\circ}C$.