In-depth considerations for better polyelectrolytes as interfacial materials in polymer solar cells

Yeo, Jun-Seok,Kang, Minji,Jung, Yen-Sook,Kang, Rira,Lee, Seung-Hoon,Heo, Youn-Jung,Jin, Sung-Ho,Kim, Dong-Yu,Na, Seok-In Elsevier 2016 Nano energy Vol.21 No.-

<P><B>Abstract</B></P> <P>We perform a comprehensive study to achieve better polyelectrolytes (PEs) as electron-transport layers (ETLs) in polymer solar cells (PSCs). Three well-known PEs – PFN, PEIE, and WPF – are chosen as model systems and investigated with variations in their backbone structures and the state of the amine functionalities on their side chains. Respectively optimized PSCs using the three PEs exhibit different cell-performances, mainly owing to the diode characteristics of built-in potential and recombination strength. To identify how such deviated device-performances correlate with the structural features of PEs, the modulated interfaces of ITO/PEs and PEs/active layer are studied in detail. It is found that conjugated backbones and larger counter-anions on side chains can promote the modulation of ITO work functions (WFs) and that a large amount of protonated amines on PEs is beneficial for junction properties with a subsequent active layer. Additionally, our results indicate that interfacial dipole and electrical doping between the PE and active layer, in addition to WF modulation of the ITO cathode, are important for device efficiency. Accordingly, with the aid of the molecular features of PEIE, PEIE-PSCs exhibit excellent device efficiency and stability compared with PFN- and WPF-PSCs. In the PTB7-th:PC<SUB>71</SUB>BM system, a remarkable power-conversion efficiency of 9.97% is achieved with a single PEIE ETL.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chemical structure and performance of polyelectrolytes (PEs) in PSCs are correlated. </LI> <LI> Interfacial dipole and doping between PEs and active layer lead to efficient PSCs. </LI> <LI> PEIE-based PSCs have excellent device efficiency and high stability. </LI> <LI> Especially, in the PTB7-th system, encouraging efficiency of 9.97% is achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Genetic diversity for gliadin subunits of Korean and Tunisian wheat

Sang Heon Kim,Yong Jin Lee,Man Bo Lee,Yacoubi Inès,Hansu Kim,Cheolwon Lee,Yong Weon Seo 한국육종학회 2014 한국육종학회 심포지엄 Vol.2014 No.07

Gliadins are the main class of wheat seed storage proteins. Since gliadins show a high level of polymorphism as well as genetically fixed, it can be used as a marker for the genetic identification. Gliadin subunit diversity information can be useful for wheat quality breeding programs. Tunisia is a country in the North Africa bordered with the Mediterranean Sea to the north and the east but with the Sahara desert to the south, which represent extremely different growth climate. Therefore, there may be a numerous variation in Tunisian common wheat and durum wheat. Total 48 lines of wheat consisted of 32 common wheat (16 Korean wheat and 16 Tunisian common wheat) and 16 Tunisian durum wheat were incorporated in this study. Gliadins were extracted with 70% ethanol and fractionated by acid polyacrylamide gel electrophoresis (A-PAGE) at 8% in aluminum lactate buffer (pH 3.1). The gel was stained with 0.25% Coomassie Brilliant Blue (CBB) R-250. The presence of each gliadin subunit band was scored and cluster analysis was carried out. The cluster showed that wheat varieties were classified into some groups and their genetic distance could be identified. The obtained information will be helpful to the future breeding program of tetraploid durum wheat as well as hexaploid common wheats. Acknowledgement: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2012K1A3A1A09028123) and carried out with the support of “Cooperative Research Program for Agriculture Science & Technology Development (Project title: Development of high yielding wheat with stress tolerance via molecular breeding strategies, Project No. PJ008031)”, Rural Development Administration, Republic of Korea.

In-line 마그네트론 스퍼터 장치를 사용하여 산소 분위기에서 제작한 Ag 박막의 특성

구대영,김원목,조상무,황만수,이인규,정병기,이택성,이경석,조성훈,Ku, Dae-Young,Kim, Won-Mok,Cho, Sang-Moo,Hwang, Man-Soo,Lee, In-Kyu,Cheong, Byung-Ki,Lee, Taek-Sung,Lee, Kyeong-Seok,Cho, Sung-Hun 한국재료학회 2002 한국재료학회지 Vol.12 No.8

A study was made to examine the electrical, compositional, structural and morphological properties of Ag thin films deposited by DC magnetron sputtering in $O_2$ atmosphere with deposition temperature from room temperature to 15$0^{\circ}C$ using in-line sputter system. The Ag films deposited at temperature above $100^{\circ}C$ in oxygen atmosphere gave a similar specific resistivity to and even lower oxygen content than those deposited using pure Ar sputter gas The Ag films deposited with pure Ar gas was mainly composed of crystallites with [111] preferred orientation, while, for those deposited in oxygen atmosphere, more than 50% of the volume was composed of crystallites with [100] orientation. The difference in the micro structure did not cause any difference in the specific resistivity of Ag films. The results showed that the transparent conducting oxide films and the Ag films could be processed sequentially in the same deposition chamber with careful control of deposition temperature, which might result in a cost reduction for constructing the large scale in-line deposition system.

cuiD Is a Crucial Gene for Survival at High Copper Environment in Salmonella enterica Serovar Typhimurium

Sung-Young Lim,Min-Ho Joe,Sang-Sun Song,Mun-Hee Lee,John W. Foster,박용근,Soon Yong Choi,In Soo Lee 한국분자세포생물학회 2002 Molecules and cells Vol.14 No.2

Copper ion is an essential micronutrient but it is also extremely cytotoxic when it exists in excess. Our stud-ies have shown that Salmonella enterica serovar Ty-phimurium can survive potentially lethal copper expo-sures by the way of copper efflux system. A copper ion inducible gene was identified in virulent S. typhi-murium by using the technique of MudJ (Km, lac)-directed lacZYA operon fusions. A copper ion inducible strain LF153 (cuiD::MudJ) has been identified. The cuiD mutant exhibits a copper sensitive phenotype but possesses normal resistance to other metal ions, and lost DMP oxidase activity. Therefore, we suggest that cuiD is an important gene for copper homeostasis and the copper resistance response. The copper sensitive phenotype was complemented by pYL3.0 carrying cuiD+. Sequence analysis showed cuiD contains 1,614 bp encoding a 536 amino acid with a 27 amino acid signal peptide and a 509 amino acid residues compris-ing the mature peptide. The CuiD shows 81% homol-ogy to YacK, a putative multicopper oxidases which extrudes copper in Escherichia coli. This ORF contains four conserved regions that contain 12 copper ligands (types 1, 2, and 3) present in various copper homeosta-sis responsible proteins. The H2O2 sensitive phenotype of the cuiD mutant indicates that cuiD may be in-volved in oxidative stress response.

Recurrent thrombosis after endovascular treatment for malignant superior vena cava syndrome

( Sang Ho Lee ),( Sun Young Kim ),( Heung Tae Kim ),( Chang Woo Shim ),( Ho Seok Chi ),( Hye In Lee ),( Do Il Choi ),( Hyun Bum Kim ),( In Jun Lee ) 대한내과학회 2015 대한내과학회 추계학술대회 Vol.2015 No.1

Endovascular treatment (EVT) including angioplasty and stenting is an effective treatment for superior vena cava (SVC) syndrome. Recurrence of SVC syndrome is mainly caused by tumor progression and occurs in around 20% after EVT, but sometimes venous thrombosis within stent accounts for recurrence of SVC syndrome. Anticoagulation after EVT is still a controversial issue. In our case, a 73 year-old man with SVC syndrome caused by mediastinal lymph node metastasis from non-small cell lung cancer underwent EVT followed by anticoagulation with low molecular weight heparin (LMWH), but symptomatic progression due to in-stent thrombosis necessitated the second procedure after two weeks. A total of 4 sessions of EVT and anticoagulation with LMWH, warfarin and rivaroxaban did not induce durable resolution of in-stent thrombosis. The 4th EVT was done with stent -graft, but computed tomography after the last procedure revealed remained thrombus in SVC and newly developed pulmonary thromboembolism during warfarinization. Our case suggests refractory in-stent thrombosis could develop despite of anticoagulation after EVT for SVC syndrome.

Effect of Strain Aging on Tensile Behavior and Properties of API X60, X70, and X80 Pipeline Steels

Sang‑In Lee,Seung‑Yong Lee,Seok Gyu Lee,Hwan Gyo Jung,Byoungchul Hwang 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

The effect of strain aging on tensile behavior and properties of API X60, X70, and X80 pipeline steels was investigated inthis study. The API X60, X70, and X80 pipeline steels were fabricated by varying alloying elements and thermomechanicalprocessing conditions. Although all the steels exhibited complex microstructure consisting of polygonal ferrite (PF), acicularferrite, granular bainite (GB), bainitic ferrite (BF), and secondary phases, they had different fractions of microstructuresdepending on the alloying elements and thermomechanical processing conditions. The tensile test results revealed that yieldingbehavior steadily changed from continuous-type to discontinuous-type as aging temperature increases after 1% pre-strain. After pre-strain and thermal aging treatment in all the steels, the yield and tensile strengths, and yield ratio were increased,while the uniform elongation and work hardening exponent were decreased. In the case of the X80 steel, particularly, thedecrease in uniform elongation was relatively small due to many mobile dislocations in PF, and the increase in yield ratiowas the lowest because a large amount of harder microstructures such as GB, BF, and coarse secondary phases effectivelyenhanced work hardening.

In-Situ X-Ray Fluoroscopic Observation for Motion of Bubbles in Liquid Iron for Correction of Drag Coefficient Used in Numerical Simulation

In-Beom Park,Sang-Joon Kim,Hae-Geon Lee,Youn-Bae Kang 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.4

Rising of Ar bubble in C-saturated liquid iron was investigated in-situ by employing a high power X-Ray fluoroscope (maximum power of 450 kV and 4.5 mA) coupled with a high speed camera. This analysis enabled to track the actual motion of rising bubble in the liquid iron. After post-processing of X-Ray images, size, shape, velocity, and trajectory of the bubble were obtained. The bubbles were found to be not spherical, but ellipsoidal. Their average size could be estimated about 1.1×10 -2 m. The bubbles wobbled during rising and arrived at their terminal velocities within 0.1 sec. The obtained terminal velocities revealed that the governing forces acting on the motion of ellipsoidal bubble were inertia and surface force. This was quite different from that of spherical bubble which was widely used in the assumption for the numerical analysis. As a result, widely applied equation for the drag coefficient (CD = 24 (1 + 0.15Re 0.687 ) / Re) is seen to be applicable only for low Re regime, and this was also confirmed by the drag coefficient derived from the present experimental observation. Therefore, it is suggested to use the following equation for the drag coefficient CD = max [24 (1 + 0.15Re 0.687 ) / Re, 8Eo / 3(Eo + 4)]. Numerical simulation for the Ar bubble behavior in the three dimensional (3D) continuous casting mold was conducted in order to evaluate the effect of the drag coefficient for the behavior of spherical and ellipsoidal bubbles. The numerical results showed that the increased CD based on ellipsoidal regime affected the entire fluid in the mold.

Discriminative detection of indoor volatile organic compounds using a sensor array based on pure and Fe-doped In₂O₃ nanofibers

Lee, Chul-Soon,Li, Hua-Yao,Kim, Bo-Young,Jo, Young-Moo,Byun, Hyung-Gi,Hwang, In-Sung,Abdel-Hady, Faissal,Wazzan, Abdulaziz A.,Lee, Jong-Heun Elsevier 2019 Sensors and actuators. B Chemical Vol.285 No.-

<P><B>Abstract</B></P> <P>Representative indoor volatile organic compounds (VOCs) such as benzene, xylene, toluene, formaldehyde, and ethanol need to be detected in a highly sensitive and discriminative manner because of their different impact on human health. In this study, pure and 0.05, 0.1, 0.3, and 0.5 at% Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> nanofibers were prepared by electrospinning and their gas sensing characteristics toward the aforementioned VOCs were investigated. The doping of In<SUB>2</SUB>O<SUB>3</SUB> nanofiber sensor with 0.05 and 0.1 at% Fe shifted the temperature to show the maximum responses to benzene, xylene, and toluene, and reduced responses to ethanol and formaldehyde, thus demonstrating changed gas selectivity. The gas sensing characteristics of 0.5 at% Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> nanofiber sensor were substantially different from those of the other sensors. Significantly different gas sensing patterns of pure and Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> sensors could be used to discriminate between the five different VOCs at 375 °C and to distinguish between the aromatic and non-aromatic gases at all sensing temperatures. The mechanism underlying the Fe-induced change in gas sensing characteristics has been discussed in relation to the variation of catalytic activity, morphology, oxygen adsorption, and charge carrier concentration.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fabrication of a sensor array using pure and Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> nanofibers. </LI> <LI> Discriminative detection of benzene, xylene, toluene, ethanol, and formaldehyde. </LI> <LI> Distinction between aromatic and non-aromatic indoor pollutants using sensor array. </LI> <LI> Gas sensing mechanism underlying Fe-induced change in response and selectivity. </LI> </UL> </P>

Celay/In-Ceram, Conventional In-Ceram, Empress 2 전부도재관의 변연적합도에 관한 비교 연구

양재호,여인성,이선형,한중석,이재봉,Yang, Jae-Ho,Yeo, In-Sung,Lee, Sun-Hyung,Han, Jung-Suk,Lee, Jai-Bong 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.2

There have been many studies about marginal discrepancy of single restorations made by various systems and materials. But many of statistical inferences are not definite because of sample size, measurement number, measuring instruments. etc. The purpose of this study was to compare the marginal adaptations of the anterior single restorations made by different systems and to consider more desirable statistical methods in analysing the marginal fit. The in vitro marginal discrepancies of three different all-ceramic crown systems (Celay In-Ceram. Conventional In-Ceram. IPS Empress 2 layering technique) and one control group (PFM) were evaluated and compared. The crowns were made from one extracted maxillary central incisor prepared with a 1mm shoulder margin and $6^{\circ}$ taper walls by milling machine. 10 crowns per each system were fabricated. Measurements or a crown were recorded at 50 points that were randomly selected for marginal gap evaluation. Non-parametric statistical analysis was performed for the results. Within the limits of this study, the following conclusions were drawn: 1 Mean gap dimensions and standard deviations at the marginal opening for the maxillary incisor crowns were $98.2{\pm}40.6{\mu}m$ for PFM, $83.5{\pm}18.7{\mu}m$ for Celay In-Ceram, $104.9{\pm}44.1{\mu}m$ for conventional In-Ceram, and $45.5{\pm}11.5{\mu}m$ for IPS Empress 2 layering technique. The IPS Empress 2 system showed the smallest marginal gap (P<0.05). The marginal openings of the other three groups were not significantly different (P<0.05). 2 The marginal discrepancies found in this study were all within clinically acceptable standards ($100\sim150{\mu}m$). 3. When the variable is so controlled that the system may be the only one, mean value is interpreted to be the marginal discrepancy of a restoration which is made by each system and standard deviation is to be technique-sensitivity of each one. 4. From the standard deviations. the copy-milling technique (Celay/In-Ceram) was not considered to be technique-sensitive in comparison with other methods. 5. Parametric analysis is more reliable than non-parametric one in interpretation of the mean and standard deviation. The sample size of each group has to be more than 30 to use parametric statistics. The level of clinically acceptable marginal fit has not been established. Further studies are needed.

The Carnegie-Chicago Hubble Program: Discovery of the Most Distant Ultra-faint Dwarf Galaxy in the Local Universe

Lee, Myung Gyoon,Jang, In Sung,Beaton, Rachael,Seibert, Mark,Bono, Giuseppe,Madore, Barry American Astronomical Society 2017 ASTROPHYSICAL JOURNAL LETTERS - Vol.835 No.2

<P>Ultra-faint dwarf galaxies (UFDs) are the faintest known galaxies, and due to their incredibly low surface brightness, it is difficult to find them beyond the Local Group. We report a serendipitous discovery of a UFD, Fornax UFD1, in the outskirts of NGC 1316, a giant galaxy in the Fornax cluster. The new galaxy is located at a projected radius of 55 kpc in the south-east of NGC 1316. This UFD is found as a small group of resolved stars in the Hubble Space Telescope images of a halo field of NGC 1316, obtained as part of the Carnegie-Chicago Hubble Program. Resolved stars in this galaxy are consistent with being mostly metal-poor red giant branch (RGB) stars. Applying the tip of the RGB method to the mean magnitude of the two brightest RGB stars, we estimate the distance to this galaxy, 19.0. +/-. 1.3 Mpc. Fornax UFD1 is probably a member of the Fornax cluster. The color-magnitude diagram of these stars is matched by a 12 Gyr isochrone with low metallicity ([Fe/H]approximate to-2.4). Total magnitude and effective radius of Fornax UFD1 are M-V approximate to -7.6 +/- 0.2 mag and r(eff) = 146 +/- 9 pc, which are similar to those of Virgo UFD1 that was discovered recently in the intracluster field of Virgo by Jang & Lee. Fornax UFD1 is the most distant known UFD that is confirmed by resolved stars. This indicates that UFDs are ubiquitous and that more UFDs remain to be discovered in the Fornax cluster.</P>