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81.
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83.
Vuthichai Ervithayasuporn Junichi Abe Toshinori Matsushima Yusuke Kawakami 《Tetrahedron》2010,66(48):9348-9355
Two new classes of mono- and oligo(p-phenylene ethynylene)s grafted with polyhedral oligomeric silsesquioxanes (POSS) were synthesized via ‘click’ chemistry and palladium-catalyzed Sonogashira cross-coupling. These materials with cubic silsesquioxanes are very robust with excellent thermal stability in air (T5%loss>330 °C) and exhibited Tg>80 °C. All the compounds showed high photoluminescence with a range of blue emission and quantum yield up to 80% in the solution. Extended π conjugation molecules of oligo-pPEs POSS maintain relatively high PL quantum efficiencies in the solid state, compared to mono-pPEs POSS. A preliminary report is made of some of the materials as multilayer OLED components with active dopants PVK and PBD. 相似文献
84.
Hidekazu Kumano Satoshi Kimura Michiaki Endo Ikuo Suemune Hirotaka Sasakura Satoru Adachi Shunichi Muto Hai Zhi Song Shinichi Hirose Tatsuya Usuki 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):144
Triggered single-photon generation from InAlAs quantum dot (QD) was demonstrated for the first time. Emitted photon energy coincides with high detection efficiency range of Si single-photon detectors, which is highly suitable for free-space communication. Single-QD spectroscopy and crossed photon correlation measurements unambiguously revealed that several emitting lines observed in a single mesa structure originated from the identical QD, and two temporary competing decay processes associated with neutral states and charged states were identified. Presence of the competing process is also inferred from an analysis of steady-state photoluminescence intensities. Formation process of charged exciton in QD is also discussed. 相似文献
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86.
One of the key differences of a semiconductor optical amplifier (SOA) with internal lasing oscillation (ILO) from a SOA with external light injection (ELI) lies in a carrier-sharing mechanism. Since the internal lasing mode shares the same pool of carriers with the signals, the carriers (or photons) withdrawn from the circulating laser mode speed up the gain recovery. On the other hand, the external light injected into the SOA shortens the carrier recovery time through optical pumping without any carrier sharing involved. To find out a better scheme, we have made a comparative investigation on the effects of the ILO and ELI on the SOA performance. It turns out by way of simulation that the ELI scheme provides faster gain recovery, shorter carrier lifetime, and higher saturation power when the external injection power is higher than the internal lasing power. The performance enhancement is not so pronounced with the carrier-sharing mechanism, as the internal lasing mode itself gives rise to severe longitudinal spatial hole burning (LSHB). Nevertheless, the ILO scheme is preferable for linear-amplification applications. We also examine the use of the ELI for low-crosstalk optical amplifiers. It is found that the ELI scheme does not bring in a very strong resonance peak in the crosstalk, which appears in a SOA with ILO due to relaxation oscillations of the lasing mode. In comparison to the ILO in SOAs, the ELI into SOAs is likely to leave more optical gain for multi-channel amplification without any sacrifice on the crosstalk. 相似文献
87.
Hyperfine Interactions - First off-line tests at the ion trap facility SHIPTRAP took place. The facility is being set up to deliver very clean and cooled beams of singly-charged recoil ions (Rare... 相似文献
88.
Tungsten microcone arrays with a high aspect ratio are formed by the cumulative nanosecond pulsed-Nd:YAG laser irradiation
of single-crystal tungsten under low pressure in an inert atmosphere. The morphology of the microcones and their density were
strongly affected by the number of laser pulses. The microcones grew to a length of 20 μm with a diameter of about 1.5 μm
at the tip after irradiation with more than 1200 pulses under our experimental conditions. They may have potential applications
for emission cathodes in a field-emission display (FED) and in microelectronic devices.
Received: 8 January 2001 / Accepted: 13 June 2001 / Published online: 2 October 2001 相似文献
89.
Moon Jeon-Yeol Miura Takatsugu Imae Ichiro Park Dae-Won Kawakami Yusuke 《Silicon Chemistry》2002,1(2):139-143
Disiloxane-arylene polymers having phenylene, biphenylene, and fluorenylene groups as arylene units were synthesized by dehydrocoupling polymerization of corresponding bis(silane) derivatives with water. The reactivity of Si-H was not affected by the structure of aromatic groups in the reaction. The polymers containing biphenylene and fluorenylene units are amorphous and show higher glass transition temperatures than the polymer from 1,4-bis(dimethylsilyl)benzene. 相似文献
90.
Photoluminescence (PL) spectra and time-resolved PL are measured from around 10 to 300 K for the InGaN/GaN single quantum wells (SQWs) with well widths of 1.5, 2.5, 4 and 5 nm. For the SQWs with the well widths of 1.5 and 2.5 nm, the peak position of PL exhibits an S-shaped shift with increasing temperature. The radiative recombination time τRAD begins to increase at the temperature for the position to change from the red-shift to the blue-shift. The steep increase of τRAD is observed beyond the temperature from the blue-shift to the red-shift. For the SQWs with the well widths of 4 and 5 nm, the peak position of PL exhibits a monotonic red-shift. τRAD decreases at first and then increases with temperature. It is about 100-times longer in the low temperature region and about 10-times longer at room temperature as compared with those of the SQWs with narrower widths. 相似文献