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1.
2.
Z. Yu Y. F. Hsia X. Z. You H. Spiering P. Gutlich 《Journal of Materials Science》1997,32(24):6579-6581
A light-induced excited spin state trapping (LIESST) experiment for a thermal gradual spin crossover complex, Fetris (2-pyridylmethyl)
amine(NCS)2 or Fe(tpa) (NCS)2, was attempted for the first time. The high spin (HS) state after light inducement stayed metastable
over a period of days without relaxation at 10 K. Intersystem relaxation from a high to a low spin (LS) complex occurred at
50 K after bleaching at 10 K. Investigation of the Mossbauer spectra of the LIESST and relaxation experiment indicated that
the Debye–Waller factor was a correlation parameter of the HS fraction and that the co-operative effect played a role in the
relaxation process for such a solid compound.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
3.
A 0.9 V 92 dB Double-Sampled Switched-RC Delta-Sigma Audio ADC 总被引:1,自引:0,他引:1
Min Gyu Kim Gil-Cho Ahn Hanumolu P.K. Sang-Hyeon Lee Sang-Ho Kim Seung-Bin You Jae-Whui Kim Temes G.C. Un-Ku Moon 《Solid-State Circuits, IEEE Journal of》2008,43(5):1195-1206
A 0.9 V third-order double-sampled delta-sigma audio ADC is presented. A new method using a combination of a switched-RC technique and a floating switched-capacitor double-sampling configuration enabled low-voltage operation without clock boosting or bootstrapping. A three-level quantizer with simple dynamic element matching was used to improve linearity. The prototype IC implemented in a 0.13 CMOS process achieves 92 dB DR, 91 dB SNR and 89 dB SNDR in a 24 kHz audio signal bandwidth, while consuming 1.5 mW from a 0.9 V supply. The prototype operates from 0.65 V to 1.5 V supply with minimal performance degradation. 相似文献
4.
Myung-Sun Baek Hyung-Joon Kook Mi-Jeong Kim Young-Hwan You Hyoung-Kyu Song 《Broadcasting, IEEE Transactions on》2005,51(4):551-559
In this paper, we apply multi-antenna scheme to DAB system for high-rate transmission. In the MIMO-DAB system with a number of transmitting and receiving antennas increases the transmission rate efficiently with low multiplication operations. For channel estimation in the MIMO-DAB system, we propose a new PRS structure and evaluate the channel estimation performance. The proposed PRS structure can estimate multi-channel information based on the semi-blind processing. The performance of proposed PRS is compared with that of conventional training sequence employing Tarokh's transmission matrix. And also we investigate the performance limitation due to the imperfect channel estimation in a MIMO-DAB receiver. It has been shown that the MIMO-DAB system with multi-antennas can achieve the high-rate transmission for multimedia broadcasting and the performance of MIMO-DAB system is impaired by imperfect channel information. 相似文献
5.
设{Z,(W)}是定义在概率空间上的独立的随机变量序列,Z(W)具有方差为期望E(Zn)=0.本文证明了对任意算数序列{bn}及任意的存在充分大的整数N>0使当N'>N″>N时.有此不等式在随机级数研究中有重要作用. 相似文献
6.
企业办社会虽与市场经济的客观要求相悖,但石油企业大量办社会的事实仍揭示了所具备的理性面。认为国家作为不受所有者监督的代理者对石油企业的要求,石油企业的行业特性以及在传统体制下长期运作所成的定热是石油企业办社会的主要原因。 相似文献
7.
For multi-step heterogeneous consecutive reactions affected entirely by interphase diffusion under isothermal condition, the
equations for the effectiveness factors, the surface concentrations and the point yields were derived in terms of the Damkoehler
numbers or the measurables from the mass balances set up on the assumption that the mass-transfer rate balances the surface-reaction
rate at steady state.
From the analyses of the equations derived, the effectiveness factors for the intermediate steps and the surface concentrations
of intermediates were understood to be enhanced by the measurables inclusive of the concentrations and the mass-transfer coefficients.
Then the effect of the concentrations was concluded to be most significant. The effects of these measurables to the effectiveness
factors and the surface concentrations were qualitatively discussed for simple consecutive reactions and also for additive
consecutive reactions. Especially, as for two-step additive consecutive reactions, the effects of measurables η Da and the
concentrations to the effectiveness factors were examined with graphical presentations.
Finally, the brief discussion of the dependency of the Damkoehler number upon reaction time and the effect of the Renolds
number and diffusivity to the extent of the mass-transfer resistance were presented. 相似文献
8.
9.
Polyester‐based polyurethane/nano‐silica composites were obtained via in situ polymerization and investigated by Fourier‐transform infrared spectroscopy (FTIR), or FTIR coupled with attenuated total reflectance (FTIR‐ATR), Transmission electron microscopy (TEM), atomic force microscopy (AFM), an Instron testing machine, dynamic mechanical analysis (DMA) and ultraviolet‐visible spectrophotometry (UV‐vis). FTIR analysis showed that in situ polymerization provoked some chemical reactions between polyester molecules and nano‐silica particles. FTIR‐ATR, TEM and AFM analyses showed that both surface and interface contained nano‐silica particles. Instron testing and DMA data showed that introducing nano‐silica particles into polyurethane enhanced the hardness, glass temperature and adhesion strength of polyurethane to the substrate, but also increased the resin viscosity. UV‐vis spectrophotometry showed that nano‐silica obtained by the fumed method did not shield UV radiation in polyurethane films. Copyright © 2003 Society of Chemical Industry 相似文献
10.
地基设计是整个建(构)筑物设计中的重要组成部分,它关系到建(构)筑物的安全及其功能能否正常发挥。本文着重分析探讨了在地基设计中应遵循的原则及注意事项。以保证建(构)筑物的安全和正常使用,充分发挥地基的作用。 相似文献