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991.
Seonae Lee Dr. Ka Young Kim Prof. Sung Ho Jung Dr. Ji Ha Lee Dr. Mihoko Yamada Dr. Ramarani Sethy Prof. Tsuyoshi Kawai Prof. Jong Hwa Jung 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(52):19054-19058
Finely controlled circularly polarized luminescence (CPL) supramolecular polymerization based on a tetraphenylethene core with four l ‐ or d ‐alanine branch side chains (l ‐ 1 and d ‐ 1 ) in the solution state is presented, resulting from the tuning of mechanical stimulus. Weak, green emissions of l ‐ 1 and d ‐ 1 in tetrahydrofuran (THF) were converted into strong blue emissions by tuning the mechanical stimulus. The strong blue emissions were caused by an aggregation‐induced emission (AIE) effect during the formation of a supramolecular polymer. Lag time in the supramolecular polymerization was drastically reduced by the mechanical stimulus, which was indicative of the acceleration of the supramolecular polymerization. A significant enhancement of circular dichroism (CD) and CPL signals of l ‐ 1 and d ‐ 1 was observed by tuning the rotational speed of the mechanical stimulus, implying that the chiral supramolecular polymerization was accelerated by the mechanical stimulus. 相似文献
992.
Annette M. Krais Yoon Jung Park Guido Reifenberger Michael Meister Christoph Plass Heinz H. Schmeiser 《Electrophoresis》2019,40(9):1293-1297
A new sensitive analytical method using capillary electrophoresis with laser induced fluorescence (CE‐LIF) was applied for the simultaneous detection of DNA methylation and hydroxymethylation levels in human cancers of different origin. DNA hydroxymethylation, measured as 5‐hydroxymethylcytosine (5hmC) levels, was decreased in gliomas with mutation in the isocitrate dehydrogenase 1 (IDH1) gene when compared to IDH1‐wildtype gliomas. Independent from IDH1 mutation, 5hmC levels were decreased in lung carcinomas when compared to normal lung tissue. Reduced DNA hydroxymethylation was also observed upon dedifferentiation in cultured murine embryonic fibroblasts. Our data show that reduced DNA hydroxymethylation is related to cellular dedifferentiation and can be detected in various types of cancers, independent from the IDH1 mutation status. Quantitative determination of altered 5hmC levels may therefore have potential as a biomarker linked to cellular differentiation and tumorigenesis. 相似文献
993.
Philipp Jung Arthur D. Ziegler Jan Blankenburg Holger Frey 《Angewandte Chemie (International ed. in English)》2019,58(37):12883-12886
Glycidyl tosylate appears to be a non‐polymerizable epoxide when nucleophilic initiators are used because of the excellent leaving group properties of the tosylate. However, using the monomer‐activated mechanism, this unusual monomer can be copolymerized with ethylene oxide (EO) and propylene oxide (PO), respectively, yielding copolymers with 7–25 % incorporated tosylate‐moieties. The microstructure of the copolymers was investigated via in situ 1H NMR spectroscopy, and the reactivity ratios of the copolymerizations have been determined. Quantitative nucleophilic substitution of the tosylate‐moiety is demonstrated for several examples. This new structure provides access to a library of functionalized polyethers that cannot be synthesized by conventional oxyanionic polymerization. 相似文献
994.
Dr. So-Yeon Park Sehoon Han Dr. Younghoon Kim Prof. Sohee Jung Prof. Dong Hoe Kim Dr. Gill Sang Han Prof. Hyun Suk Jung 《Chemphyschem》2019,20(20):2657-2661
Multiple exciton generation (MEG) has great potential to improve the Shockley-Queisser (S-Q) efficiency limitation for colloidal quantum dot (CQD) solar cells. However, MEG has rarely been observed in CQD solar cells because of the loss of carriers through the transport mechanism between adjacent QDs. Herein, we demonstrate that excess charge carriers produced via MEG can be efficiently extracted using monolayer PbS QDs. The monolayer PbS QDs solar cells exhibit α=1 in the light intensity dependence of the short-circuit current density Jsc (Jsc∝Iα) and an internal quantum efficiency (IQE) value of 100 % at 2.95 eV because of their very short charge extraction path. In addition, the measured MEG threshold is 2.23 times the bandgap energy (Eg), which is the lowest value in PbS QD solar cells. We believe that this approach can provide a simple method to find suitable CQD materials and design interface engineering for MEG. 相似文献
995.
The SU(1,1) coherent states, so-called Barut-Girardello coherent state and Perelomov coherent state, for the generalized two-mode time-dependent quadratic Hamiltonian system are investigated through SU(1,1) Lie algebraic formulation. Two-mode Schrödinger cat states defined as an eigenstate of $\hat{K}_{-}^{2}The SU(1,1) coherent states, so-called Barut-Girardello coherent state and Perelomov coherent state, for the generalized two-mode
time-dependent quadratic Hamiltonian system are investigated through SU(1,1) Lie algebraic formulation. Two-mode Schr?dinger
cat states defined as an eigenstate of
are also studied. We applied our development to two-mode Caldirola-Kanai oscillator which is a typical example of the time-dependent
quadratic Hamiltonian system. The time evolution of the quadrature distribution for the probability density in the coherent
states are analyzed for the two-mode Caldirola-Kanai oscillator by plotting relevant figures. 相似文献
996.
We constructed a novel tunable comb-filter by splicing a commercial Yb3+ doped fiber (YDF) between 2 thermally expanded core (TEC) fibers at their core-expanded ends. This structure forms an all-fiber Mach-Zehnder interferometer due to the interference between the core mode and the cladding modes of the YDF. The interference fringes shifts to the longer wavelength region as the YDF is pumped by a 980 nm laser diode (LD). We then demonstrated application of this newly proposed tunable comb-filter to a SOA-based ring laser and obtained multi-wavelength lasing. The lasing wavelengths can be also tuned by pumping the YDF in the proposed comb-filter. 相似文献
997.
We have performed high resolution angle-resolved photoemission (ARPES) studies on electron-doped cuprate superconductors Sm2-xCexCuO4 (x=0.10, 0.15, 0.18), Nd2-xCexCuO4 (x=0.15), and Eu2-xCexCuO4 (x=0.15). Imaginary parts of the electron removal self energy show steplike features due to an electron-bosonic mode coupling. The steplike feature is seen along both nodal and antinodal directions but at energies of 50 and 70 meV, respectively, independent of the doping and rare earth element. Such energy scales can be understood as being due to preferential coupling to half- and full-breathing mode phonons, revealing the phononic origin of the kink structures. Estimated electron-phonon coupling constant lambda from the self energy is roughly independent of the doping and momentum. The isotropic nature of lambda is discussed in comparison with the hole-doped case where a strong anisotropy exists. 相似文献
998.
Ae Kim S Min Byun K Lee J Hoon Kim J Albert Kim DG Baac H Shuler ML June Kim S 《Optics letters》2008,33(9):914-916
We demonstrate that surface plasmon resonance (SPR) is applicable to the optical detection of neural signals. A low-noise SPR sensor was developed as a label- and artifact-free method for the extracellular recording of neural activity. The optical responses obtained from a rat sciatic nerve were highly correlated with simultaneously recorded electrical responses. Additional studies with stimulation intensity and lidocaine further confirmed that the optically measured signals originated from neural activities. 相似文献
999.
Dae Seung Cho 《Applied Acoustics》2008,69(11):1120-1128
A highway traffic noise prediction model has been developed for environmental assessment in South Korea. The model is based on an outdoor sound propagation method and is fully compliant with ISO 9613 and the sound power level (PWL) estimation for a road segment, as suggested in the ASJ Model-1998 that is based on PWLs. Due to that model’s selection of two pavement types, such as asphalt or concrete pavement, an unacceptable traffic noise prediction is made in cases where the road surface is different from that on which the model is based. In order to address this problem, several road surface types are categorized, and the PWL of each surface type is determined and modeled by measuring the noise levels obtained from newly developed methods. An evaluation of the traffic noise prediction model using field measurements finds good agreement between predicted and measured noise levels. 相似文献
1000.
The vaccum-ultra-violet (VUV)- and UV-excited luminescent properties of MgGa2O4:Mn2+ phosphor with various co-dopants were investigated. Spinel-structured manganese-activated magnesium gallate exhibited intense green emission with the spectrum centered at 503 nm under 147 and 254 nm excitation induced by the transition from the lowest excited state to the ground state, 4T1-6A1, of the tetrahedral-sited Mn2+. With optimized incorporation ranges, Eu3+, Ce3+ and Al3+ co-doping, enhanced the overall fluorescence efficiency under 147 nm and these could be tentatively interpreted in terms of optical properties of host compounds and co-doped ions. 相似文献