http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kim, Byungkwon,Song, Jungho,Kim, Jeong-Yeol,Hwang, Jungho,Park, Dongho Elsevier 2018 Advanced powder technology Vol.29 No.12
<P><B>Abstract</B></P> <P>The nanoparticle production process in a transferred arc plasma system was studied. The plasma temperature, particle heating time, and particle residence time in plasma were calculated using heat and mass balance with a lumped capacitance method. We analyzed the nanoparticle production characteristics based on different operating conditions by comparing the particle vaporization time with the particle residence time in the plasma. The limit size for particle vaporization was derived. With higher plasma power, the nanoparticle production rate increased and the energy consumption rate decreased. It was confirmed that the energy consumption rate reaches an optimal point according to the plasma power. Experiments to determine the nanoparticle production rate according to plasma power were also conducted and the experimental data were compared with numerical values. The results show that the error rate between the numerical values and experimental data was approximately ±18%. Therefore, the developed model which was studied could be useful for designing nanoparticle production process using a transferred arc plasma system because of its simple approach.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanoparticle production process in a transferred arc plasma system was studied. </LI> <LI> Nanoparticle production characteristics were analyzed for varying conditions. </LI> <LI> Numerical values agreed well with experimental results. </LI> <LI> The method can be useful for design of large-scale nanoparticle production systems. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kim, Min Jo,An, Hye Jin,Kim, Dae Hyun,Lee, Bonggi,Lee, Hye Jin,Ullah, Sultan,Kim, Su Jeong,Jeong, Hyoung Oh,Moon, Kyoung Mi,Lee, Eun Kyeong,Yang, Jungho,Akter, Jinia,Chun, Pusoon,Moon, Hyung Ryong,Chu Elsevier 2018 Bioorganic & medicinal chemistry letters Vol.28 No.4
<P><B>Abstract</B></P> <P>The NAD<SUP>+</SUP>-dependent deacetylase SIRT1, which is associated with the improvement of metabolic syndromes, such as type 2 diabetes, is a well-known longevity-related gene. Several <I>in vitro</I> and <I>in vivo</I> studies have shown the known protective effects of SIRT1 activators, such as resveratrol and SRT1720, on diabetes- or obesity-induced fatty liver and insulin resistance. Here, we newly synthesized 18 benzoxazole hydrochloride derivatives based on the structure of resveratrol and SRT1720. We performed an <I>in vitro</I> SIRT1 activity assay to identify the strongest SIRT1 activator. The assay confirmed MHY2233 to be the strongest SIRT1 activator (1.5-fold more potent than resveratrol), and docking simulation showed that the binding affinity of MHY2233 was higher than that of resveratrol and SRT1720. To investigate its beneficial effects, db/db mice were orally administered MHY2233 for 1 month, and various metabolic parameters were assessed in the serum and liver tissues. MHY2233 markedly ameliorated insulin signaling without affecting body weight in db/db mice. In particular, the mRNA expression of lipogenic genes, such as acetyl CoA carboxylase, fatty acid synthase, and sterol regulatory element-binding protein, which increased in db/db mice, decreased following oral treatment with MHY2233.</P> <P>In conclusion, the novel SIRT1 activator MHY2233 reduced lipid accumulation and improved insulin resistance. This finding may contribute toward therapeutic approaches for fatty liver disease and glucose tolerance.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kim, Jonggi,Yun, Myoung Hee,Kim, Gi-Hwan,Lee, Jungho,Lee, Sang Myeon,Ko, Seo-Jin,Kim, Yiho,Dutta, Gitish K.,Moon, Mijin,Park, Song Yi,Kim, Dong Suk,Kim, Jin Young,Yang, Changduk American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.10
<P>The introduction of fluorine (F) atoms onto conjugated polymer backbone has verified to be an effective way to enhance the overall performance of polymer-based bulk-heterojunction (BHJ) solar cells, but the underlying working principles are not yet fully uncovered. As our attempt to further understand the impact of F, herein we have reported two novel fluorinated analogues of PCDTBT, namely, <B>PCDTFBT</B> (1F) and <B>PCDT2FBT</B> (2F), through inclusion of either one or two F atoms into the benzothiadiazole (BT) unit of the polymer backbone and the characterization of their physical properties, especially their performance in solar cells. Together with a profound effect of fluorination on the optical property, nature of charge transport, and molecular organization, F atoms are effective in lowering both the HOMO and LUMO levels of the polymers without a large change in the energy bandgaps. <B>PCDTFBT</B>-based BHJ solar cell shows a power conversion efficiency (PCE) of 3.96 % with high open-circuit voltage (<I>V</I><SUB>OC</SUB>) of 0.95 V, mainly due to the deep HOMO level (−5.54 eV). To the best of our knowledge, the resulting <I>V</I><SUB>OC</SUB> is comparable to the record <I>V</I><SUB>OC</SUB> values in single junction devices. Furthermore, to our delight, the best <B>PCDTFBT</B>-based device, prepared using 2 % v/v diphenyl ether (DPE) additive, reaches the PCE of 4.29 %. On the other hand, doubly-fluorinated polymer <B>PCDT2FBT</B> shows the only moderate PCE of 2.07 % with a decrease in <I>V</I><SUB>OC</SUB> (0.88 V), in spite of the further lowering of the HOMO level (−5.67 eV) with raising the number of F atoms. Thus, our results highlight that an improvement in efficiency by tuning the energy levels of the polymers by means of molecular design can be expected only if their truly optimized morphologies with fullerene in BHJ systems are materialized.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-10/am500891z/production/images/medium/am-2014-00891z_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am500891z'>ACS Electronic Supporting Info</A></P>
Kim, Taewook,Park, June Hyun,Lee, Sang-gil,Kim, Soyoung,Kim, Jihyun,Lee, Jungho,Shin, Chanseok Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.8
MicroRNAs (miRNAs) are essential small RNA molecules that regulate the expression of target mRNAs in plants and animals. Here, we aimed to identify miRNAs and their putative targets in Hibiscus syriacus, the national flower of South Korea. We employed high-throughput sequencing of small RNAs obtained from four different tissues (i.e., leaf, root, flower, and ovary) and identified 33 conserved and 30 novel miRNA families, many of which showed differential tissuespecific expressions. In addition, we computationally predicted novel targets of miRNAs and validated some of them using 5' rapid amplification of cDNA ends analysis. One of the validated novel targets of miR477 was a terpene synthase, the primary gene involved in the formation of disease-resistant terpene metabolites such as sterols and phytoalexins. In addition, a predicted target of conserved miRNAs, miR396, is SHORT VEGETATIVE PHASE, which is involved in flower initiation and is duplicated in H. syriacus. Collectively, this study provides the first reliable draft of the H. syriacus miRNA transcriptome that should constitute a basis for understanding the biological roles of miRNAs in H. syriacus.
Kim, Joong-Kwon,Kim, Do Hyeong,Joo, Se Hun,Choi, Byeongwook,Cha, Aming,Kim, Kwang Min,Kwon, Tae-Hyuk,Kwak, Sang Kyu,Kang, Seok Ju,Jin, Jungho American Chemical Society 2017 ACS NANO Vol.11 No.6
<P>Here, we introduce regenerated fibers of chitin (Chiber), the second most abundant biopolymer after cellulose, and propose its utility as a nonwoven fiber separator for lithium metal batteries (LMBs) that exhibits an excellent electrolyte-uptaking capability and Li-dendrite mitigating performance. Chiber is produced by a centrifugal jet-spinning technique, which allows a simple and fast production of Chibers consisting of hierarchically aligned self-assembled chitin nanofibers. Following the scrutinization on the Chiber-Li-ion interaction via computational methods, we demonstrate the potential of Chiber as a nonwoven mat-type separator by monitoring it in Li-O-2 and Na-O-2 cells.</P>
Reference thermal neutron field at KRISS for calibration of neutron detectors
Kim, Yun Ho,Park, Hyeonseo,Kim, Yong Kyun,Kim, Jungho,Kang, Jeongsoo Elsevier 2017 Radiation measurements Vol.107 No.-
<P><B>Abstract</B></P> <P>A reference thermal neutron field has been established at the Korea Research Institute of Standards and Science (KRISS) by using a <SUP>241</SUP>Am-Be neutron source and a high-purity graphite pile constructed by stacking graphite blocks. The properties of the graphite blocks such as impurities, density, and dimensions were studied thoroughly to understand the characteristics of the generated field. The energy spectrum and thermal neutron fractions were simulated with the Monte Carlo N-Particle eXtended code using measured physical parameters. The neutron effective temperature was 308 K, and the fraction of thermal neutrons was approximately 95% at the reference position of the thermal neutron field. The thermal neutron fluence rate was determined by adopting the Westcott convention method based on neutron activation analysis using a gold foil. The Westcott fluence rate for thermal neutron at the reference position was (2326.7 ± 8.4) cm<SUP>−2</SUP>s<SUP>−1</SUP>. The true thermal neutron fluence rate at the reference position in the KRISS thermal neutron field was (2700 ± 29) cm<SUP>−2</SUP>s<SUP>−1</SUP> (at the reference date of June 30, 2014). The response of a spherical proportional counter with He-3 (SP9 neutron detector) was evaluated in the newly established field as (3.083 ± 0.045) cm<SUP>2</SUP> for the reference calibration condition (a parallel neutron beam with a Maxwellian energy distribution having a most probable energy of 0.025 eV).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermal neutron field was developed for the calibration of neutron detectors. </LI> <LI> A <SUP>241</SUP>Am-Be neutron source and a pure graphite pile were used for the construction. </LI> <LI> Monte Carlo simulation was performed to understand characteristics of the field. </LI> <LI> Thermal neutron fluence rate was determined based on neutron activation analysis. </LI> <LI> The sensitivity of the SP9 detector was calibrated with an uncertainty of ∼3%. </LI> </UL> </P>