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751.
Guan‐Yeow Yeap Tiang‐Chuan Hng Wan Ahmad Kamil Mahmood Masato M. Ito Yamashita Youhei Yoichi Takanishi 《Liquid crystals》2013,40(9):979-986
A series of eight liquid crystalline compounds, N,N′‐bis[(2‐hydroxy‐4‐alkoxyphenyl)methylene]benzene‐1,4‐diamines, has been synthesized and characterized. These homologous compounds differ in the length of terminal alkyl group C n H2n+1 wherein n is an even number ranging from 4 to 18. The spectroscopic techniques, FTIR, 1H NMR and 13C NMR, were employed to characterize the molecular structure. The transition temperatures of all the title compounds and their mesophases were studied by differential scanning calorimetry and polarizing microscopy. All the compounds were smectogenic, exhibiting both tilted and non‐tilted molecular orientation in their smectic phases. Further investigation to ascertain the anisotropic nature of subphases within the smectogenic region was carried out using X‐ray diffraction. 相似文献
752.
Onda K Ogihara S Yonemitsu K Maeshima N Ishikawa T Okimoto Y Shao X Nakano Y Yamochi H Saito G Koshihara SY 《Physical review letters》2008,101(6):067403
The quasistable state in the photoinduced phase transition for the quasi-one-dimensional quarter-filled organic conductor (EDO-TTF)2PF6 has been examined by ultrafast reflective measurements and time-dependent model calculations incorporating both electron-electron and electron-phonon interactions. The transient optical conductivity spectrum over a wide probe photon-energy range revealed that photoexcitation induced a new type of charge-disproportionate state. Additionally, coherent and incoherent oscillations dependent on probe photon energies were found, as predicted by the calculation. 相似文献
753.
Ando Y 《Physical review letters》2008,100(2):029701; discussion 029702
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755.
Shigeo Yamaguchi Hitoshi Kurusu Yoichi Kawakami Shizuo Fujita Shigeo Fujita 《Superlattices and Microstructures》1998,23(6):1189-1195
Photo-pumped lasing properties have been investigated in a CdSe/ZnSe/ZnSSE single quantum wells (SQWs) with the well-layer thickness (LW) of 1, 2 and 3 monolayer (ML). At 20 K, the laser threshold for the SQW withLW = 1 ML was the lowest in spite of the smallest active layer thickness. The carrier (exciton) sheet density at the threshold (n)thwas estimated to be as low as 7 × 1010cm−2, which is well below Mott's screening density. Time-resolved photoluminescence has revealed that the localized biexciton band, whose peak energy agrees with the lasing peak, appeared on the low-energy side of the main PL peak at this level of carrier concentrations. Theoretical calculation has also shown that the localized biexciton recombination has to be taken into account for the lasing process. On the contrary, thenthvalues of the SQWs with 2 and 3 ML are 1 order of magnitude larger than that of the SQW with 1 ML. This may be due to the smaller oscillator strength of both localized excitons and localized biexcitons because of the larger inhomogeneous broadening, resulting in an increased carrier density for achieving optical gain sufficient to overcome the reflection losses. 相似文献
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758.
Application of partial least square on quantitative analysis of L-, D-, and DL-tartaric acid by terahertz absorption spectra 总被引:1,自引:0,他引:1
Nishikiori R Yamaguchi M Takano K Enatsu T Tani M de Silva UC Kawashita N Takagi T Morimoto S Hangyo M Kawase M 《Chemical & pharmaceutical bulletin》2008,56(3):305-307
Absorption spectra of polycrystalline L-, D-, and DL-tartaric acid have been measured by terahertz time domain spectroscopy (THz-TDS). Different absorption bands are observed for DL-tartaric acid and its enantiomers (L- and D-tartaric acid). This result shows that the THz-TDS can be used for distinguishing between DL-tartaric acid and enantiomers (L- and D-tartaric acid). Moreover, partial least square (PLS) can be found to improve the quantitation of L-tartaric acid in L- and DL-tartaric acid mixture by THz-TDS. 相似文献