Experimental evidence of hydrogen-oxygen decoupled diffusion into BaZr_0.6Ce_0.25Y_0.15O_3-δ

Lim, D.K.,Im, H.N.,Jeon, S.Y.,Park, J.Y.,Song, S.J. Elsevier Science 2013 ACTA MATERIALIA Vol.61 No.4

The electrical properties of BaZr<SUB>0.6</SUB>Ce<SUB>0.25</SUB>Y<SUB>0.15</SUB>O<SUB>3-δ</SUB> (BZCY) were studied as a function of both oxygen partial pressure (-2.65≤log(P<SUB>O'2</SUB>atm<SUP>-1</SUP>)≤-0.62) and water vapor activity (-3.33≤log(P<SUB>H'2O</SUB>atm<SUP>-1</SUP>≤-1.3)) in the temperature range of 973-1073K. The total conductivity slightly increased in reducing atmospheres with increasing water vapor activity because of the relative contribution to the total conductivity by the redox reaction at the given thermodynamic conditions. The partial conductivities of protons, holes and oxygen vacancies were successfully calculated, and the activation energy determined for proton transport was 0.3+/-0.1eV. The chemical diffusivity of oxygen at a fixed water vapor activity, D~<SUB>vO</SUB>, could only be evaluated from Fick's second law during oxidation and reduction at the fixed water vapor activity. However, twofold nonmonotonic conductivity relaxation behaviors were clearly confirmed in the temperature range investigated during hydration/dehydration. If P<SUB>O'2</SUB> represents the fixed oxygen partial pressure, D~<SUB>iH</SUB> is the hydrogen chemical diffusivity at P<SUB>O'2</SUB> and D~<SUB>vH</SUB> is the oxygen chemical diffusivity at P<SUB>O'2</SUB>, it was observed that D~<SUB>iH</SUB>>D~<SUB>vH</SUB> at all experimental conditions, suggesting that the hydrogen chemical diffusion is always faster than oxygen on hydration/dehydration in the temperature range studied.

색소환원시간에 의한 우육의 신속 미생물 검사법에 관한 연구

임상동,김기성,박윤경 한국동물자원과학회 2001 한국축산학회지 Vol.43 No.2

In order to investigate a reliable and rapid evaluation method in estimating the microbial contents in beef, the resazurin color reduction method was adopted and investigated in views of analysis cost; lavor-savings, time-consumption. and accuracy. The results were summarized as follows; Regression equation(RE) between resazurin reduction time(X) from blue color to bluish purple color during incubation at 25℃, 30℃ and 35℃ and initial bacterial log count(Y) was Y = -0.1337X + 4.6387, Y = -0.2661X + 4.8435 and Y = -0.2405X + 4.4971, with a correlation coefficient of -0.25, -0.44 and -0.32, respectively. The times required to obtain results were 4.8 to 19.7hr, 3.2 to 10.7hr and 2.1 to 10.4hr, respectively. RE between resazurin reduction time(X) from blue color to purple color during incubation at 25℃, 30℃ and 35℃ and initial bacterial log count(Y) was Y = -0.2434X + 5.7529. Y = -0.3161X + 5.8029 and Y = -0.3853X + 5.8168, with a correlation coefficient of -0.68, -0.73 and -0.66, respectively. The times required to obtain results were 7.2 to 15.4hr, 5.7 to 12.0hr and 4.7 to 9.9hr, respectively. RE between resazurin reduction time(X) from blue color to pink color during incubation at 25℃. 30℃ and 35℃ and initial bacterial log count(Y) was Y = -0.3066X + 6.9948, Y = -0.3759X + 7.1319 and Y = -0.3324X + 6.2307, with a correlation coefficient of -0.92. -0.93 and -0.69, respectively. The times required to obtain results were 9.8 to 16.3hr. 8.3 to 13.7hr and 6.7 to 12.7hr, respectively.

The new diterpene isodojaponin D inhibited LPS-induced microglial activation through NF-kappaB and MAPK signaling pathways

Lim, J.Y.,Won, T.J.,Hwang, B.Y.,Kim, H.R.,Hwang, K.W.,Sul, D.,Park, S.Y. North-Holland ; Elsevier Science Ltd 2010 european journal of pharmacology Vol.642 No.1

Neuroinflammation with prolonged microglial activation leads to increased levels of pro-inflammatory mediators and subsequently contributes to neuronal dysfunction and neuronal loss. Therefore, pharmacological suppression of neuroinflammation would theoretically slow the progression of neurodegenerative disease. In this study, we investigated the anti-inflammatory effects and possible mechanisms of isodojaponin D (19-hydroxy-1α,6-diacetoxy-6,7-seco-ent-kaur-16-en-15-one-7,20-olide), a new diterpene isolated from Isodon japonicus against lipopolysaccharide(LPS)-induced microglial activation in BV2 cells. Results from RT-PCR and Western blot showed that pretreatment with isodojaponin D (5 and 10μg/ml) prior to treatment with LPS (1μg/ml) significantly decreased LPS-induced production of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in a dose-dependent manner. In addition, LPS-induced pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α, were also decreased by pretreatment with isodojaponin D. This effect was accompanied by a decrease in translocations of Nuclear Factor-KappaB (NF-κB) p50 and p65 from the cytoplasm to the nucleus and by a decrease in I kappaB (IκB) degradation. In addition, pretreatment with isodojaponin D significantly attenuated LPS-induced mitogen-activated protein kinase (MAPK) activation. Taken together, these results suggest that isodojaponin D suppressed LPS-induced microglial activation and production of pro-inflammatory mediators by inhibition of the NF-κB signaling pathway and phosphorylation of MAPKs. These results suggest that isodojaponin D could play a beneficial role in treatment of neurodegenerative disease.

200 GeV/핵자 유황이온과 핵건판핵의 충돌에 의해 생성된 헬륨 파쇄핵의 극한파쇄 연구

김동철,송진섭,윤천실,정성헌,박인곤,김종오,김철수,김태연,이승희,조재희,천병구,김재률,김준원,김태익,박명렬,장한일,임인택 慶尙大學校 기초과학연구소 1992 基礎科學硏究所報 Vol.8 No.-

고에너지 중이온 원자핵과 핵건판의 충돌에서, 200GeV/핵자 유황이온에 의해 생성된 파쇄 헬륨핵(Z=2)의 실험실계의 방출각 분포는 표적핵에 무관한 회귀공식. dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)]로 잘 표현된다. 여기에서 의사신속도 η=-ln[tan(θ/2)]이고, y_b는 실험실계의 입사입자(^32S)의 신속도이다. 이 공식에 의한 적합에서 k=-0.057±0.008로 얻어진다. 즉, 핵건판과 고에너지 중이온의 충돌에서 파쇄 헬륨핵의 exp(η-y_b)의 분포는 "극한파쇄" 현상을 잘 설명하고 있다. The angular distribution of emission angle θ of helium (Z=2) produced in the collisions of incident particles of 200 GeV/nucleon ^32S in nuclear emulsion is well expressed by dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)] where the pseudorapidity is η=-ln[tan(θ/2)], the laboratory system primary rapidity is y_b, and k=-0.057+0.008. The shape of this frequency of occurrence distributions in terms of exp(η-y_b) attests to the validity of the concept of "limiting fragmentation" for helium projectile fragments produced in the projectile fragmentation regions of heavy ion collisions in nuclear emulsion.

Structure-property relationship of D-A type copolymers based on thienylenevinylene for organic electronics

Kim, Y.A.,Jeon, Y.J.,Kang, M.,Jang, S.Y.,Kim, I.B.,Lim, D.H.,Heo, Y.J.,Kim, D.Y. Elsevier Science 2017 Organic electronics Vol.46 No.-

A series of D-A type conjugated polymers based on (E)-1,2-bis(3-dodecyllthiophen-2-yl)ethene (TV) as electron donor unit and with different repeating subunits, PTVBO8, PTVBT8, PTVTBO12, and PTVTBT12 were synthesized for use in organic field effect transistors and bulk heterojunction organic photovoltaics. Upon incorporation of alkoxy substituents in acceptor units, benzooxadiazole (BO) and benzothiadiazole (BT), polymer solubility improved and higher molecular weight polymers were obtained. In addition, all copolymers showed favorable thermal stability (T<SUB>d</SUB> > 300 <SUP>o</SUP>C), and low band gap properties (1.49-1.67 eV). The thiophene-flanked TV-TBX copolymers, PTVTBO12 and PTVTBT12, exhibited higher molecular weight and superior device performance in both OFETs and OPVs compared with the TV-BX copolymers. The electronic energy levels of copolymers were strongly influenced by the nature of acceptor units, while optical band gaps and shape of molecular orientation of polymer chains were affected by the presence or absence of thiophene spacer. Charge carrier mobilities in TV-TBX copolymers were 1 order of magnitude greater than in TV-BX copolymers. OFETs based on a PTVTBT12 with TG/BC configuration displayed the highest hole mobility of 0.48 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP>. The photovoltaic device containing a PTVTBO12:PC<SUB>71</SUB>BM (1:2 w/w) blend system exhibited best performance with a V<SUB>oc</SUB> of 0.56 V, a short-circuit current density (Jsc) of 13.1 mA cm<SUP>-2</SUP>, a fill factor (FF) of 69%, and a power conversion efficiency (PCE) of 5.0%.

The crystal structure and electrochemical performance of Li_1.167Mn_0.548Ni_0.18Co_0.105O₂ composite cathodes doped and co-doped with Mg and F

Lim, S.N.,Seo, J.Y.,Jung, D.S.,Park, S.B.,Yeon, S.H. Elsevier Sequoia 2015 Journal of Electroanalytical Chemistry Vol.740 No.-

The crystal structure and electrochemical performance of Li ion cathodes doped and co-doped with Mg and F (Li<SUB>1.167</SUB>Mn<SUB>0.548-x</SUB>Mg<SUB>x</SUB>Ni<SUB>0.18</SUB>Co<SUB>0.105</SUB>O<SUB>2-y</SUB>F<SUB>y</SUB> where x=0, 0.02 and/or y=0, 0.02) was investigated. The effects of doping and co-doping were measured with XRD, XPS, and galvanostatic charge/discharge tests. The lattice constant and cell volume decreased when doped with Mg, while they increased when doped with F. The change in local structure was due to changes in the oxidation states of the transition metals. Mg doping decreases the Ni<SUP>2+</SUP>/Ni<SUP>3+</SUP> ratio and increases the Mn<SUP>3+</SUP>/Mn<SUP>4+</SUP> ratio, while F doping increases the Ni<SUP>2+</SUP>/Ni<SUP>3+</SUP> ratio. The altered oxidation states of Ni and Mn also influence the electrochemical performance. Mg-and F-doped cathodes showed increased initial discharge capacity (253mAhg<SUP>-1</SUP>) and cycle performance (95%) respectively when compared to the undoped performance (248mAhg<SUP>-1</SUP> and 86%). However, Mg and F doping deteriorates cycle performance and lowers discharge capacity respectively. While Mg and F doping had both positive and negative aspects, it was found that co-doping caused synergistic behavior, with the dopants offsetting the changes in local structure. This increased the discharge capacity (259mAhg<SUP>-1</SUP>) and improved cycle performance (90%).

S-Noetherian properties on amalgamated algebras along an ideal

Lim, J.W.,Oh, D.Y. North-Holland Pub. Co 2014 Journal of pure and applied algebra Vol.218 No.6

Let A and B be commutative rings with identity, f:A→B a ring homomorphism and J an ideal of B. Then the subring A@?<SUP>f</SUP>J:={(a,f(a)+j)|a@?A and j@?J} of AxB is called the amalgamation of A with B along with J with respect to f. In this paper, we investigate a general concept of the Noetherian property, called the S-Noetherian property which was introduced by Anderson and Dumitrescu, on the ring A@?<SUP>f</SUP>J for a multiplicative subset S of A@?<SUP>f</SUP>J. As particular cases of the amalgamation, we also devote to study the transfers of the S-Noetherian property to the constructions D+(X<SUB>1</SUB>,...,X<SUB>n</SUB>)E[X<SUB>1</SUB>,...,X<SUB>n</SUB>] and D+(X<SUB>1</SUB>,...,X<SUB>n</SUB>)E@?X<SUB>1</SUB>,...,X<SUB>n</SUB>@? and Nagata@?s idealization.

전도성 고분자의 광 특성을 이용한 가스센서의 개발

임채근,이상문,이윤수,허용현,방영일,권오식,허증수,이덕동 경북대학교 센서기술연구소 2002 센서技術學術大會論文集 Vol.13 No.1

Surface exchange kinetics and chemical diffusivities of BaZr_0.2Ce_0.65Y_0.15O_3-δ by electrical conductivity relaxation

Lim, D.K.,Jeon, S.Y.,Singh, B.,Park, J.Y.,Song, S.J. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.610 No.-

Perovskite-type oxide BaCe<SUB>0.65</SUB>Zr<SUB>0.2</SUB>Y<SUB>0.15</SUB>O<SUB>3-δ</SUB> (BCZY2015) was synthesized by a solid state reaction method. BCZY2015 samples were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The time dependent variation in electrical conductivity of BCZY2015 was monitored during the oxidation/reduction in oxygen partial pressure (pO<SUB>2</SUB>) range of -2.28≤log(pO<SUB>2</SUB>/atm)≤-0.68 at a fixed water vapor pressure (pH<SUB>2</SUB>O), and during the hydration/dehydration in -3.15≤log(pH<SUB>2</SUB>O/atm)≤-2.35 range in air. The electrical conductivity showed a monotonic relaxation behavior by the ambipolar diffusion of V<SUB>o</SUB><SUP>??</SUP> and OH<SUB>o</SUB><SUP>?</SUP> during the oxidation/reduction and the relaxation process was governed by the diffusivity of oxygen (D@?<SUB>vO</SUB>). On the other hand, during the hydration/dehydration process, a non-monotonic twofold relaxation behavior was observed due to the decoupled diffusion of H and O components with the mediation of holes, and the conductivity relaxation process was governed by the diffusivities of both H (D@?<SUB>iH</SUB>) and O (D@?<SUB>vH</SUB>). The values of surface exchange coefficients and diffusivities of oxygen and hydrogen were calculated from Fick's second law by the nonlinear least squares fitting of the conductivity data, as proposed by Yoo et al. (2008).

군장병의 헌혈을 통한 말라리아 전파의 위험성에 대한 조사

임채승,김영기,이갑노,염용태,김순덕,김대성,황유성,오홍범,김두성 대한감염학회 1997 감염 Vol.29 No.2

목적:국내 헌혈 혈액에서 전염병 감염 방지를 위해 시행하는 감염표지자 중 말라리아를 검출하려는 노력은 최근의 비무장지대 내의 군장병에서의 말라리아 재발생에도 불구하고 활성화 되어 있지 않다. 일반적으로 말라리아가 토착화 된 지역을 거주하거나 여행한 사람 중 말라리아에 걸렸거나 치료한 경력 있는 사람은 치료가 끝난 후라도 3년내에는 헌혈을 금지하도록 규정하고 있다. 저자들은 국내 헌혈의 중요 부분(57.8%)을 차지하는 군인에서 헌혈시 말라리아 전파의 위험성을 파악하고자 본 조사를 실시하였다. 방법:1995년 5월에서 1996년 10월까지 군병원에 입원한 환자중 말라리아로 확진된 174명의 환자에서 면담 및 입원 기록을 추적하여 병력과 헌혈 기록을 확인 한 뒤 헌혈장소, 헌혈일, 헌혈 기록을 확인 한 뒤 헌혈장소, 헌혈일, 헌혈 횟수를 조사하여 환자의 증상 발병일과의 간격 및 연관성 분석하였고 이를 기준으로 공혈 혈액의 수혈시 말라리아의 전파 위험성을 평가하였다. 결과:전체 174명의 환자중에서 1회라도 헌혈을 시행한 사람은 70.7%인 123명에 해당하였고 환자의 증상 시작일과 헌혈일과의 간격은 2일에서 평균 2750일(평균 377알, 표준편차 488일)의 분포를 보였다. 증상시작일과 헌혈일의 간격이 3년 이내인 경우는 전체의 87.8%에 해당하였다. 말라리아 치료후 헌혈을 실시한 경우는 (n=18) 모두 치료 후 3년 이내에 헌혈을 하였다. 헌혈장소는 토착형 말라리아의 호발 지역과 동일하였는데 경기도 파주시(40%)와 연천군(29%) 및 철원(15.5%) 기타(15.5%)순이었다. 결론:한국에서 토착형 말라리아 군인 환자들의 병력조회에서 헌혈에 의한 전염가능성이 존재하는 기간 내에 헌혈이 적지 않게 실시되고 있어서 이들 지역에서의 군헌혈을 실시하는 경우 엄격한 헌혈자 선별기준 적용되어야 할 것으로 생각된다. Background: Screening of donor blood for malaria has not been activated in Korea yet in spite of the recent resurgence of tertian malaria among Korean army soldiers in Delimited Militarized Zone areas. Prospective donors(travellers, immigrants, refugees, citizens or residents) following a visit to or coming from and endemic area who have had malaria or taken antimalarial prophylaxis should be deferred for 3 years after cessation of therapy or after depature from malarial area. We studied the risk of the transmission of malaria, especially through army blood donation which comprised up to 57.8% of whole blood donation in Korea. Methods: The data were collected by personal interview and review of donation records of Korea Red Cross Center and medical records from 174 army soldiers with malaria who admitted to Army Hospital from May 1995 to October 1996. We analysed the time interval between onset of illness and blood donation, and geographic distribution of the patients. Results: About 70.7%(123/174) of the patients donated blood before the onset of illness, and the internal between blood donation and onset of illness ranged from 2 days to 2,750 days (mean 377, standard deviation488). Patients who donated blood within 3 years before onset of illness were 87.8%(n=108) of the total blood donation. All donation (n=18) after treatment were within 3 years from 46 days to 342 days(mean 138, standard deviation 80.7). The frequent of blood donations were from the prevalent areas of malaria such as Pajoo City(40%), Younchon Kun(29%), Cholwon Kun(15.5%) and others(15.5%). Conclusion: We showed that donated army blood a risk of malaria transmission. Therefore the blood bank needs to set strict guidelines for blood donation especially from Korean army soldiers to control malaria transmission.