http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Full Color Stop Bands in Hybrid Organic/Inorganic Block Copolymer Photonic Gels by Swelling−Freezing
Kang, Changjoon,Kim, Eunjoo,Baek, Heeyoel,Hwang, Kyosung,Kwak, Dongwoo,Kang, Youngjong,Thomas, Edwin L. American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.22
<P>We report a facile way of fabricating hybrid organic/inorganic photonic gels by selective swelling and subsequent infiltration of SiO(2) into one type of lamellar microdomain previously self-assembled from modest-molecular-weight block copolymers. Transparent, in-plane lamellar films were first prepared by assembly of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP), and subsequently the P2VP domains were swollen with a selective solvent, methanol. The swollen structures were then fixated by synthesizing SiO(2) nanoparticles within P2VP domains. The resulting frozen photonic gels (f-photonic gels) exhibited strong reflective colors with stop bands across the visible region of wavelengths.</P>
Broad-wavelength-range chemically tunable block-copolymer photonic gels
Kang, Youngjong,Walish, Joseph J.,Gorishnyy, Taras,Thomas, Edwin L. Nature Publishing Group 2007 NATURE MATERIALS Vol.6 No.12
Responsive photonic crystals have been developed for chemical sensing using the variation of optical properties due to interaction with their environment. Photonic crystals with tunability in the visible or near-infrared region are of interest for controlling and processing light for active components of display, sensory or telecommunication devices. Here, we report a hydrophobic block–hydrophilic polyelectrolyte block polymer that forms a simple one-dimensional periodic lamellar structure. This results in a responsive photonic crystal that can be tuned via swelling of the hydrophilic layers by contact with a fluid reservoir. The glassy hydrophobic layer forces expansion of the hydrophilic layer along the layer normal, yielding extremely large optical tunability through changes in both layer thickness and index of refraction. Polyelectrolyte polymers are known to be highly responsive to a range of stimuli. We show very large reversible optical changes due to variation of the salt concentration of a water reservoir. These one-dimensional Bragg stacks reflect incident light from the ultraviolet–visible region to the near-infrared region (λpeak=350–1,600 nm) with over a 575% change in the position of the stop band. Our work demonstrates the extremely high responsivity possible for polyelectrolyte-based photonic materials.
Kang, Hungu,Lee, Haiwon,Kang, Youngjong,Hara, Masahiko,Noh, Jaegeun Royal Society of Chemistry 2008 Chemical communications Vol.2008 No.41
<P>Although the adsorption of benzenethiols (BT) on Au(111) usually leads to the formation of disordered phases, we demonstrate here that the displacement of preadsorbed cyclohexanethiol self-assembled monolayers (SAMs) on Au(111) by BT molecules can be a successful approach to obtain two-dimensional BT SAMs with long-range ordered domains.</P> <P>Graphic Abstract</P><P>Molecular-scale STM imaging reveals that the displacement of preadsorbed cyclohexanethiol self-assembled monolayers (SAMs) on Au(111) by benzenethiol (BT) can be a successful approach to obtain two-dimensional BT SAMs. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b809261c'> </P>
Choi, Jong Yong,Kang, Woonggi,Kang, Boseok,Cha, Wonsuk,Son, Seon Kyoung,Yoon, Youngwoon,Kim, Hyunjung,Kang, Youngjong,Ko, Min Jae,Son, Hae Jung,Cho, Kilwon,Cho, Jeong Ho,Kim, BongSoo American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.10
<P>Bottom-contact bottom-gate organic field-effect transistors (OFETs) are fabricated using a low band gap pDTTDPP-DT polymer as a channel material and single-layer graphene (SLG) or Au source/drain electrodes. The SLG-based ambipolar OFETs significantly outperform the Au-based ambipolar OFETs, and thermal annealing effectively improves the carrier mobilities of the pDTTDPP-DT films. The difference is attributed to the following facts: (i) the thermally annealed pDTTDPP-DT chains on the SLG assume more crystalline features with an edge-on orientation as compared to the polymer chains on the Au, (ii) the morphological features of the thermally annealed pDTTDPP-DT films on the SLG electrodes are closer to the features of those on the gate dielectric layer, and (iii) the SLG electrode provides a flatter, more hydrophobic surface that is favorable for the polymer crystallization than the Au. In addition, the preferred carrier transport in each electrode-based OFET is associated with the HOMO/LUMO alignment relative to the Fermi level of the employed electrode. All of these experimental results consistently explain why the carrier mobilities of the SLG-based OFET are more than 10 times higher than those of the Au-based OTFT. This work demonstrates the strong dependence of ambipolar carrier transport on the source/drain electrode and annealing temperature.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-10/acsami.5b00747/production/images/medium/am-2015-00747f_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b00747'>ACS Electronic Supporting Info</A></P>
Ahn, Youshin,Kim, Eunjoo,Hyon, Jinho,Kang, Changjoon,Kang, Youngjong WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.23
<P>Block copolymer photonic gels exhibiting multiple colors in response to near‐UV radiation are demonstrated by Y. Kang and co‐workers on page OP 127. The counterions pairing with the polyelectrolyte in the gel layers determine the photosensitivity of photonic gels. The simple replacement of ions can make the photonic gels either highly sensitive or insensitive to near‐UV. The illustration shows ionic signaling giving “STOP” and “GO” cues for the photoresponse of these photonic gels. </P>
YoungJong Kim,JinKyung Park,WonSub Kang,SuKang Kim,Changsu Han,HaeRi Na,HaeJeong Park,JongWoo Kim,YoungYoul Kim,MoonHo Park,JongWoo Paik 대한신경정신의학회 2017 PSYCHIATRY INVESTIGATION Vol.14 No.1
Objective-Mitochondrial dysfunction is a prominent and early feature of Alzheimer’s disease (AD). The morphologic changes observed in the AD brain could be caused by a failure of mitochondrial fusion mechanisms. The aim of this study was to investigate whether genetic polymorphisms of two genes involved in mitochondrial fusion mechanisms, optic atrophy 1 (OPA1) and mitofusin 2 (MFN2), were associated with AD in the Korean population by analyzing genotypes and allele frequencies. Methods-One coding single nucleotide polymorphism (SNP) in the MFN2, rs1042837, and two coding SNPs in the OPA1, rs7624750 and rs9851685, were compared between 165 patients with AD (83 men and 82 women, mean age 72.3±4.41) and 186 healthy control subjects (82 men and 104 women, mean age 76.5±5.98). Results-Among these three SNPs, rs1042837 showed statistically significant differences in allele frequency, and genotype frequency in the co-dominant 1 model and in the dominant model. Conclusion-These results suggest that the rs1042837 polymorphism in MFN2 may be involved in the pathogenesis of AD.
Kim, Eunjoo,Kang, Changjoon,Baek, Heeyoel,Hwang, Kyosung,Kwak, Dongwoo,Lee, Eunkyung,Kang, Youngjong,Thomas, Edwin L. WILEY‐VCH Verlag 2010 Advanced Functional Materials Vol.20 No.11
<P><B>Abstract</B></P><P>Polystyrene‐<I>block</I>‐poly(2‐vinyl pyridine) (PS‐<I>b</I>‐P2VP) block copolymer photonic gels are fabricated that exhibit controllable optical hysteresis in response to a cyclic pH sweep. The optical hysteresis is tuned by controlling the ion‐pairing affinity between various anions and the protonated pyridinium ions on the P2VP block, which is highly dependent on the hydration energy of the ions, the dielectric constant of the solvent, and the ionic strength of the medium. The pH coercivity defining the magnitude of hysteresis of the photonic gels could be varied from 0.26 to 7.4. Photonic gel films with strong optical hysteresis can serve as wet photonic memory films where information can be cyclically recorded and erased at least 15 times and maintained for at least 96 h. The memory colors can be further tuned by selection of the copolymer molecular weight.</P>