ortho‐Selective Nucleophilic Addition of Primary Amines to Silylbenzynes: Synthesis of 2‐Silylanilines     

Takashi Ikawa  Tsuyoshi Nishiyama  Takashi Shigeta  Shinya Mohri  Shinsuke Morita  Sho‐ichi Takayanagi  Yuki Terauchi  Yuki Morikawa  Akira Takagi  Yoshinobu Ishikawa  Satoshi Fujii  Yasuyuki Kita  Shuji Akai 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2011,123(25):5792-5795

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Atsuhiko Fukuyama  Taketo Aihara  Yuki Yokoyama  Michiya Kojima  Hiromasa Fujii  Hidetoshi Suzuki  Masakazu Sugiyama  Yoshiaki Nakano  Tetsuo Ikari 《physica status solidi (a)》2014,211(2):444-448

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Yuki Katsurada  Shuzo Hirata  Kenro Totani  Toshiyuki Watanabe  Martin Vacha 《Advanced Optical Materials》2015,3(12):1726-1737

Photoreversible on–off recording of red persistent room‐temperature phosphorescence (RTP) is demonstrated. Host–guest materials composed of a persistent phosphorescent guest (D), a photochromic guest (A), and an amorphous steroidal host show red persistent RTP with a lifetime longer than 1 s based on D. The red persistent RTP function is erased by ultraviolet irradiation and recovered by irradiation with green light. The reversible photocyclization and decyclization of A allows and prevents dual dipole–dipole energy transfer from the singlet and triplet states of D to the ground state of A, respectively. The occurrence and lack of dual dipole–dipole energy transfer trigger the deactivation and activation of red persistent RTP from D, respectively. In samples labeled by the recording material, the RTP function of a specific target can be selectively activated using green light irradiation and the movement of the target can be detected as red persistent emission signal without interference from the movement of other persistent phosphorescent species as well as excitation light scattering.  相似文献   

    

Qinghui Li  Rina Suzuki  Yuki Ono  Izumi Nakai  Keiichi Tanaka  Satoshi Nakayama  Haruo Takahashi 《X射线光谱测定》2009,38(5):369-375

Suspended particulate matter (SPM) collected in the urban area of Tokyo was analyzed using a transition edge sensor (TES) microcalorimeter x‐ray detector mounted on a FE‐SEM system. This prototype microcalorimeter spectrometer with an energy resolution of 19 eV identified some severe peak overlaps in the spectra measured by the traditional Si(Li) solid state detector, including S Kα with Pb Mα, Zn Lα with Na Kα, and Ti Kα with Ba Lα. In addition, the TES microcalorimeter showed good spatial resolution for the microanalysis of SPM. The focused ion beam(FIB) was successfully applied to fabricate a cross section of a single SPM particle. The chemical compositonal difference between surface and inner parts, and among different surface parts of the SPM was also determined. Through combination of the FIB technique and the TES microcalorimeter, we achieved a better understanding of the SPM. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

    

Satoshi Iwatsuki  Yuki Kanamitsu  Hidetaka Ohara  Eisuke Watanabe  Koji Ishihara 《Journal of Physical Organic Chemistry》2012,25(9):760-768

The pK_as of 3‐pyridylboronic acid and its derivatives were determined spectrophotometrically. Most of them had two pK_as assignable to the boron center and pyridine moiety. The pK_a assignment performed by ¹¹B nuclear magnetic resonance spectroscopy revealed that both boron centers in 3‐pyridylboronic acid [3‐PyB(OH)₂] and the N‐methylated derivative [3‐(N‐Me)Py⁺B(OH)₂] have strong acidities (pK_a = 4.4 for both). It was found that introduction of a substituent to pyridine‐C atom in 3‐pyridylboronic acid drastically increased the acidity of the pyridinium moiety, but decreased the acidity of the boron center, whereas the introduction to pyridine‐N atom had no influence on the acidity of the boron center. Kinetic studies on the complexation reactions of 3‐pyridinium boronic acid [3‐HPy⁺B(OH)₂] with 4‐isopropyltropolone (Hipt) carried out in strongly acidic aqueous solution indicated that the positive charge on the boronic acid influenced little on its reactivity; 3‐HPy⁺B(OH)₂ reacts with Hipt and protonated H₂ipt⁺, and its reactivity was in line with those of a series of boronic acids. Kinetics in weakly acidic aqueous solution revealed that 3‐HPy⁺B(OH)₂ reacts with Hipt faster than its conjugate boronate [3‐HPy⁺B(OH)₃^–], which is consistent with our recent results. The reactivity of 3‐(N‐Me)Py⁺B(OH)₂ towards Hipt was also examined kinetically; the reactivities of 3‐(N‐Me)Py⁺B(OH)₂ and 3‐(N‐Me)Py⁺B(OH)₃^– are almost the same as those of their original 3‐HPy⁺B(OH)₂ and 3‐HPy⁺B(OH)₃^–, respectively. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

    

T Tahara  Y Shimozato  Y Awatsuji  K Nishio  S Ura  O Matoba  T Kubota 《Optics letters》2012,37(2):148-150

We propose a single-shot digital holography in which the complex amplitude distribution is obtained by spatial-carrier phase-shifting (SCPS) interferometry and the correction of the inherent phase-shift error occurred in this interferometry. The 0th order diffraction wave and the conjugate image are removed by phase-shifting interferometry and Fourier transform technique, respectively. The inherent error is corrected in the spatial frequency domain. The proposed technique does not require an iteration process to remove the unwanted images and has an advantage in the field of view in comparison to a conventional SCPS technique.  相似文献   

    

Ichirou Nomura  Yuki Nakai  Koichi Hayami  Takumi Saitoh  Katsumi Kishino 《physica status solidi b》2006,243(4):924-928

Aging characteristics of BeZnSeTe yellow light emitting diodes (LEDs) fabricated on InP substrates by molecular beam epitaxy were investigated under direct current injections at room temperature. It was shown that the decay speed of the light output during the aging was slower than that of conventional ZnCdSe/MgZnSSe LEDs. A long lifetime more than 5000 h and a half lifetime of 5180 h were obtained at a current density of 130 A/cm². The half lifetimes of the BeZnSeTe LEDs were about three orders of magnitude greater than that of the ZnCdSe/MgZnSSe LEDs. These results proved high reliability of the BeZnSeTe LED. Investigating the aging characteristics of the applied voltage, the injection current, and the emission spectra showed that the output decay was caused by degradation of the active layer of the LEDs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

    

T. Ishiguro  Y. Toda  S. Adachi  M. Arita  Y. Arakawa 《physica status solidi b》2006,243(7):1564-1567

We have studied exciton spin relaxation in strained GaN epilayers on various sapphire substrates using spindependent transient reflectivity and three‐pulse four‐wave mixing measurements. Strikingly fast exciton spin relaxation (<1 ps) at 10 K was observed in the lowest exciton level (A‐exciton) both in bulk and GaN layer on c‐sapphire. In contrast, the transient signals in the GaN layer on a‐sapphire show the break down of the spin polarization caused by the exchange interaction. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

    

S. Minagawa  K. Arakawa  M. Yamada 《physica status solidi (a)》1980,57(2):713-718

The elastic constants of diamond and its local moment of inertia are estimated. The diamond crystal is assumed as a Cosserat continuum with constrained rotation. After a brief survey on the dispersion relations for waves in the continuum, the micropolar material constants are evaluated from the experimental data on the lattice vibrations in diamond. Numerical results are presented.  相似文献   

    

K. Hoshino  T. Someya  Y. Arakawa 《physica status solidi (a)》2001,188(2):877-880

We have investigated electron Hall mobility of high‐quality GaN/AlGaN multiple quantum wells (QWs). Electron mobility was enhanced from 875 to 1600 cm²/Vs at room temperature in GaN/Al_0.58Ga_0.42N QWs when the number of QWs increased from 1 to 10. Atomic force microscopy analysis shows that the multilayered QWs blocks the threading dislocations and results in improved quality of the GaN/Al_0.58Ga_0.42N heterointerfaces, thus enhancing the electron Hall mobility. The dependence of electron mobility and the root‐mean‐square surface roughness (obtained by atomic force microscopy) on well width shows that mobility is mainly dominated by interface roughness scattering processes in quantum wells less than 4 nm thick.  相似文献