Optical spectroscopy of PPV-based block copolymers of nanostructured supramolecular organic semiconductor.

Yang, Q,Battle, R,Zhang, C,Ma, S M,Seo, J T,Tabibi, B,Temple, D,Sun, S,Jung, S S,Namkung, M American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.2

<P>The third-order nonlinearity of a PPV-based nanostructured supramolecular organic semiconductor (DBAB), with an electron donor (D) connected to an electron acceptor (A) via nonconjugated and flexible bridge (B) units, was investigated in this work at both near-resonant (532 nm) and nonresonant (1064 nm) wavelength by using degenerate four-wave mixing. The second hyperpolarizabilities of D, A, and DBAB at 532 nm were found to be approximately 2.42 x 10(-43) m2/V2, 7.75 x 10(-44) m2/V2, and 1.80 x 10(-43) m2/V2 in copolarization geometry, and approximately 1.59 x 10(-43) m2/V2, 2.59 x 10(-44) m2/V2, and 1.18 x 10(-43) m2/V2 in orthogonal polarization geometry, respectively. The second hyperpolarizabilities of DBAB at 1064 nm were approximately 1.66 x 10(-46) m2/V2 and approximately 8.77 x 10(-47) m2/V2 for parallel and orthogonal polarization cases.</P>

유한요소법을 이용한 단순인장 시험편의 탄소성파괴인성치 예측

선동주(D.J.Sun),박명균(M.K.Park),박세만(S.M.Bahk),최영택(Y.T.Choi) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.11_2

In oder to predict the elastic-plastic fracture toughness for metallic materials, Finite Element Method(FEM) was used for analysis of compact tension specimen. ASTM E399 test procedure was adopted for simulation of FEM. The Load-Crack Mouth Opening Displacement curve obtained from this analysis was used to detect the crack initiation point and determine the elastic-plastic fracture toughness J_IC. In order to prove the results, they were compared with the results from previous experiments and they agree with experimental results.

원발성 간암에서 PIVKA-II 및 Lens Culinaris Agglutinin-A 반응성 Alpha-fetoprotein(AFP-L3)의 임상적 유용성

배시현,박두호,양진모,박영민,차상복,최종영,성광용,조세현,정규원,선희식,김부성,최상욱,변병훈,한남익 대한간학회 2000 Clinical and Molecular Hepatology(대한간학회지) Vol.6 No.2

Background/Aims: Des-γ-carboxy prothrombin(DCP), a protein induced by vitamin K absence or antagonist-II(PIVKA-II), and Lens culinaris agglutinin-A reactive AFP-L3 have been reported to be useful markers for the diagnosis of hepatocellular carcinoma (HCC). In the present study, both the PIVKA-II and AFP-L3 were analyzed and compared with a conventional AFP to determine its usefulness, specificity and sensitivity in the diagnosis of HCC. Methods: Sera were collected from 108 patients consisting of 17 patients with chronic hepatitis, 22 patients with liver cirrhosis and 69 patients with HCC. The AFP-L3 was determined by an lectin affinity electrophoresis coupled with an antibody-affinity blotting. Level of DCP was measured by an enzyme immunoassay with an anti-DCP monoclonal antibody. Results: The sensitivity and specificity of PIVKA-II and AFP L3 were 49.3% and 89.5%, and 32.5% and 85.7%, respectively. No significant correlation was found between the PIVKA-II or AFP L3 and serum AFP. No correlation was found etween the PIVKA-II or AFP L3 and the characteristics of HCC. Conclusion: The determination of plasma DCP and AFP L3 levels combined with AFP levels may be useful especially for the differential diagnosis between HCC and chronic liver diseases without HCC.(Korean J HepatoBackground/Aims: Des-γ-carboxy prothrombin(DCP), a protein induced by vitamin K absence or antagonist-II(PIVKA-II), and Lens culinaris agglutinin-A reactive AFP-L3 have been reported to be useful markers for the diagnosis of hepatocellular carcinoma (HCC). In the present study, both the PIVKA-II and AFP-L3 were analyzed and compared with a conventional AFP to determine its usefulness, specificity and sensitivity in the diagnosis of HCC. Methods: Sera were collected from 108 patients consisting of 17 patients with chronic hepatitis, 22 patients with liver cirrhosis and 69 patients with HCC. The AFP-L3 was determined by an lectin affinity electrophoresis coupled with an antibody-affinity blotting. Level of DCP was measured by an enzyme immunoassay with an anti-DCP monoclonal antibody. Results: The sensitivity and specificity of PIVKA-II and AFP-L3 were 49.3% and 89.5%, and 32.5% and 85.7%, respectively. No significant correlation was found between the PIVKA-II or AFP-L3 and serum AFP. No correlation was found etween the PIVKA-II or AFP L3 and the characteristics of HCC. Conclusion: The determination of plasma DCP and AFP-L3 levels combined with AFP levels may be useful especially for the differential diagnosis between HCC and chronic liver diseases without HCC.(Korean J Hepatol 2000;6:205-214)l 2000;6:205-214)

Unveiling the sodium intercalation properties in Na_1.86□_0.14Fe₃(PO₄)₃

Essehli, R.,Ben Yahia, H.,Maher, K.,Sougrati, M.T.,Abouimrane, A.,Park, J.-B.,Sun, Y.-K.,Al-Maadeed, M.A.,Belharouak, I. Elsevier Sequoia 2016 Journal of Power Sources Vol. No.

<P><B>Abstract</B></P> <P>The new compound Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> was successfully synthesized via hydrothermal synthesis and its crystal structure was determined using powder X-ray diffraction data. Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> was also characterized by operando XRD and Mössbauer spectroscopy, cyclic voltammetry, and galvanostatic cycling. Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> crystallizes with the alluaudite-type structure with the eight coordinated Na1 and Na2 sodium atoms located within the channels. The combination of the Rietveld- and Mössbauer-analyses confirms that the sodium vacancies in the Na1 site are linked to a partial oxidation of Fe<SUP>2+</SUP> during synthesis. The electrochemical tests indicated that Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> is a 3 V sodium intercalating cathode. At the current densities of 5, 10, and 20 mA g<SUP>−1</SUP>, the material delivers the specific capacities of 109, 97, and 80 mA h g<SUP>−1</SUP>, respectively. After 100 charge and discharge cycles, Na<SUB>1.86</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> exhibited good sodium removal and uptake behavior although no optimizations of particle size, morphology, and carbon coating were performed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> was synthesized via hydrothermal synthesis method. </LI> <LI> Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> crystallizes with the Alluaudite-type structure. </LI> <LI> Operando in situ XRD and Mössbauer spectroscopy studies were carried on. </LI> <LI> The crystal structure of Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> is stable during cycling. </LI> <LI> Na<SUB>1.86</SUB>□<SUB>0.14</SUB>Fe<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> is a promising 3 V cathode material for sodium ion batteries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Na1.86□0.14Fe3(PO4)3 was synthesized via hydrothermal synthesis method. Na1.86Fe3(PO4)3 crystallizes with the alluaudite-type structure. Na1.86Fe3(PO4)3 is a 3 V sodium intercalating cathode. At the current densities of 5, 10, and 20 mA g<SUP>−1</SUP>, the material delivers the specific capacities of 109, 97, and 80 mA h g<SUP>−1</SUP>, respectively. After 100 charge and discharge cycles, Na1.86Fe3(PO4)3 exhibited good sodium removal and uptake behavior with a stable crystal structure.</P> <P>[DISPLAY OMISSION]</P>

Improving mechanical and magnetocaloric responses of amorphous melt-extracted Gd-based microwires via nanocrystallization

Belliveau, H.F.,Yu, Y.Y.,Luo, Y.,Qin, F.X.,Wang, H.,Shen, H.X.,Sun, J.F.,Yu, S.C.,Srikanth, H.,Phan, M.H. Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.692 No.-

<P><B>Abstract</B></P> <P>We report on the structural, mechanical, and magnetocaloric properties of annealed melt-extracted Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> amorphous microwires of ∼70 μm diameter. During heat treatment small islands of nanocrystallities are generated and isolated in the amorphous region for the wires. The size of the nanocrystallities ranges from 5 nm to 10 nm. The observed lattice distortion from the nanocrystallities causes changes in the magnetic properties of the wires. The annealing temperature of 100 °C has the largest strength (1845 MPa) as compared to wires annealed at other temperatures. This is likely to trigger nanophase transformation in the amorphous region and these nanocrystals have been preserved through the increase of annealing temperature. The formulation of the nanocrystalline islands is also verified by the selected-area electron diffraction (SAED). The microwires exhibit a large and reversible magnetocaloric effect (MCE), with the maximum isothermal magnetic entropy change (−Δ<I>S</I> <SUB>M</SUB>) and refrigerant capacity (<I>RC</I>) values of 9.5 J/kg K and 689 J/kg respectively for the microwire annealed at 100 °C. This <I>RC</I> is about 35%, 67%, and 91% larger than those of bulk Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> (∼509 J/kg), Gd (∼410 J/kg), and Gd<SUB>5</SUB>Si<SUB>2</SUB>Ge<SUB>1.9</SUB>Fe<SUB>0.1</SUB> (∼360 J/kg) regardless of their ordering temperatures. These results demonstrate the ability to tune the mechanical and magnetic properties of the microwires by thermal annealing.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The impact of nanocrystallization in Gd<SUB>53</SUB>Al<SUB>24</SUB>Co<SUB>20</SUB>Zr<SUB>3</SUB> microwires. </LI> <LI> Enhanced mechanical strength. </LI> <LI> Enhanced magnetocaloric response. </LI> </UL> </P>

Determination of the absolute configuration of chaetoviridins and other bioactive azaphilones from the endophytic fungus <i>Chaetomium globosum</i>

Youn, Ui Joung,Sripisut, Tawanun,Park, Eun-Jung,Kondratyuk, Tamara P.,Fatima, Nighat,Simmons, Charles J.,Wall, Marisa M.,Sun, Dianqing,Pezzuto, John M.,Chang, Leng Chee Elsevier 2015 Bioorganic & medicinal chemistry letters Vol.25 No.21

<P><B>Abstract</B></P> <P>Chemical investigation of an endophytic fungus <I>Chaetomium globosum</I> isolated from leaves of <I>Wikstroemia uva-ursi</I> led to the isolation of two new azaphilones, chaetoviridins J and K (<B>1</B> and <B>3</B>), along with five known derivatives (<B>2</B> and <B>4</B>–<B>7</B>). The structures of azaphilones were determined by NMR, X-ray diffraction, Mosher’s method, and CD analysis. The isolated compounds were evaluated for their cancer chemopreventive-potential based on their abilities to inhibit tumor necrosis factor alpha (TNF-α)-induced nuclear factor-kappa B (NF-κB). Compounds <B>4</B>, <B>5</B>, <B>7</B>, and synthetic <B>8</B> and <B>9</B> inhibit nitric oxide (NO) production with IC<SUB>50</SUB> values in the range of 0.3–5.8μM. Compounds <B>4</B>, <B>5</B>, and <B>9</B> also displayed (TNF-α)-induced NF-κB activity with IC<SUB>50</SUB> values in the range of 0.9–5.1μM.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

3차원 탄소성 유한요소법을 통한 금속복합재료와 지르코니아 접합체의 잔류응력해석

주재황,선동주,최영택,박세만,박명균 明知大學校 産業技術硏究所 1996 産業技術硏究所論文集 Vol.15 No.-

Employing a three dimensional finite element method a thermal elasto-plastic stress analysis was conducted to investigate residual stress distributions on the joining area between a ceramic(ZrO₂) and a SiC whisker-reinforced aluminum (Al composite). For purposes of comparisons, residual stresses at the interfaces on the joining area were first analyzed for varying volume fractions of SiC whiskers utilizing two dimensional elasto-plastic models. The results from the 2-D models were compared with those from 3-D models to understand the Practical nature of residual stresses produced during industrial joining processes for ceramics and metal matrix composites. Additionally, the same procedures were applied to compute stress variations along a line passing through the joining area to obtain a physical insight and to offer a plausible explanations for fracture patterns occuring at the interfaces during bending.

유한요소법을 이용한 금속재료의 탄소성파괴인성치 결정에 관한 연구

박명균,최영택,박세만,선동주 明知大學校 産業技術硏究所 1998 産業技術硏究所論文集 Vol.17 No.-

In oder to predict the elastic-plastic fracture toughness for metallic materials, Finite element Method(FEM) was used for analysis of compact tension specimen. ASTM E399 test procedure was adopted for simulation of FEM. The Load-Crack Mouth Opening Displacement curve obtained from this analysis was used to detect the crack initiation point and determine the elastic-plastic fracture toughness Jic. In order to prove the results, they were compared with the results from previous experiments and they agree with experimental results.

有限要素法을 이용한 열사이클 荷重壯態에서의 세라믹 /金屬 接合材의 强度 平價

최영택,박명균,박세만,선동주 明知大學校 産業技術硏究所 1998 産業技術硏究所論文集 Vol.17 No.-

In this work, variations of residual stresses are investigated by varying thicknesses of copper interlayers inserted for stress relaxations. Futhermore, various modes of stress distributions are evaluated under different assumptions of physical situations. departing from the simple assumption and adopting new assumption is judiciously made to study variations of residual stresses under the simple and new assumption, respectively. The simple assumption dictates that temperature distributions in the ceramic/metal joints are uniform, which amounts to longer cooling time (slow cooling), while the new assumption relaxes the condition of uniform temperature distributions allowing variations of temperatures in the ceramic/metal joints. Especially, the thermal cycles are applied to ceramic/metal joints retaining residual stresses developed during joining processes. Changes in distributions of residual stresses under the applied thermal cycles and the behavior of ceramic/ metal joints formed at elevated temperatures are evaluated from finite element analysis to produce results in good agreement with the existing experimental data.

Brazing 과 Metallizing 에 의한 세라믹/금속 접합재 잔류응력의 유한요소 해석

최영택,박명균,박세만,선동주 명지대학교 대학원 1997 대학원논문집 Vol.1 No.-

In this study finite element method(FEM) is utilized to determine residual stress distributions induced by heat generated during joining processes of ceramics and metals. The finite element analysis is focused on the joining area, that comprises the interfacial area between a metal and a insert-layer, the insert-layer itself and adjoining area between the insert-layer and a ceramic. The residual stress distributions on the joining area are analyzed as function of thicknesses and yield stresses of the insert-layer(Brazing Filler Metal), and for different kinds of metals including SUS304 and SM45C. Two typical joining processes are considered in this investigation ; Active Metal Brazing and Metallizing. Stress distributions on the joining areas are computed for both processes and are compared with one another. This comparison can lead to the better joining method in reducing the residual stresses and consequently provide improved joining technologies.