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991.
甲基苯基乙烯硅橡胶具有耐高低温、防震等独特优势,在航天器的减震、密封等领域具有广泛应用前景。研究了甲基苯基乙烯基硅橡胶的电离总剂量效应。结果表明,随着辐射剂量的增加,甲基苯基乙烯基硅橡胶的力学性能出现了不同程度的退化。拉伸强度和撕裂强度变化规律以1106 Gy(Si)剂量点为分界点。低于该剂量,拉伸和撕裂随剂量增加快速下降;高于该剂量时,随辐照剂量增加,拉伸强度出现一定程度反弹,呈现出宽U形,而撕裂强度则是先增加后下降。拉断伸长率和邵氏硬度A随辐照剂量增加分别出现快速下降和增加,最终接近饱和。最后,从辐射交联和裂解方面讨论了甲基苯基乙烯基硅橡胶电离总剂量效应的潜在物理机制。 相似文献
992.
We study transmission properties in configurations composed of two single metal gratings with different thicknesses. Choosing the perfect electric conductor excludes the influence of intrinsic material dispersion on transmission behaviors; and as such, we aim to reveal the contribution of geometric dispersion to electromagnetic transmission. Transmission suppression line, instead of a transmission suppression point, is discovered, denoting the curve of the wavelength versus the interval or the lateral displacement between the two single gratings when the transmission suppression appears. A simplified model is proposed to comprehend the underlying physics of this special phenomenon. 相似文献
993.
C.-T. Zheng C.-S. Ma X. Yan X.-Y. Wang D.-M. Zhang 《Applied physics. B, Lasers and optics》2010,98(2-3):511-521
By using the extended point-matching method, coupled mode theory, and electro-optic modulation theory, design and optimization are carried out for a polymer shielded push–pull directional coupler electro-optic switch. A novel technique and the relative formulas are presented for analyzing the influences of the skin-effect on the microwave characteristic parameters and the switching performances. Simulation results show that the voltages of the cross- and bar-states are 0 and ±2.93 V, respectively, and the coupling length is 4.139 mm. Considering the influences of the skin-effect, the cutoff switching frequency is 172 GHz, the insertion loss is in the range of 1.920–1.975 dB, the crosstalk is less than ?20 dB, and the switching time is 31.18–31.40 ps within the range of the switching frequency from 0.72 to 172 GHz. The designed switch exhibits superior characteristics including good impedance match, low switching voltage, and high cutoff switching frequency. 相似文献
994.
The calculations of the P-V isotherms, Hugoniots, dissociation and ionization degrees of fluid (liquid) hydrogen isotopes have been performed by using the self-consistent fluid variational theory under isothermal and shock compression. The isotope effect of fluid hydrogen was discussed. The present results are compared with the available experiments and calculations. 相似文献
995.
The luminol-CdTe quantum dots (QDs) conjugates were prepared through the reaction between -NH2 and -COOH. The resonance energy transfer between chemiluminescence donor (luminol-H2O2 system) and quantum dots (QDs, with different emission peaks) acceptors (CRET) was investigated. The luminescence of QDs in luminol-QDs conjugates in the process of CRET was influenced by the molar ratio of luminol/QDs. It could reach higher luminescence intensity while the luminol/QDs value was 1/1. Quantum yield of QDs and overlapping areas between the emission spectrum of luminol and adsorption spectrum of QDs played important roles in the CRET efficiency of luminol-QDs conjugates. The higher CRET efficiency (21.2%) was observed when the 540 nm QDs were used as acceptors. This work will offer helpful knowledge for the CRET studies based on QDs. 相似文献
996.
Rui Zheng 《Journal of Molecular Spectroscopy》2010,263(2):174-177
The rovibrational spectrum of the Ne-N2O van der Waals complex has been recorded in the symmetric stretching mode region of the N2O monomer (∼1285 cm−1) using a tunable diode laser spectrometer in conjunction with an astigmatic multi-pass cell and a pulsed supersonic slit jet. The spectra of both 20Ne-N2O and 22Ne-N2O isotopomers are assigned and analyzed using a Watson S-reduced asymmetric-rotor Hamiltonian. The rotational and centrifugal constants for the excited vibrational state are accurately determined. The band-origin of the spectrum is determined to be ν0 = 1285.12251(18) cm−1 for 20Ne-N2O and 1285.12363(27) cm−1 for 22Ne-N2O, which shows a blue-shift of 0.21921 cm−1 for 20Ne-N2O and 0.22033 cm−1 for 22Ne-N2O from that of the N2O monomer, respectively. 相似文献
997.
A novel technique and related formulations are proposed for analyzing the influences of the skin-effect on the performances of a polymer Y-fed coupler electro-optic modulator with shielded push-pull micro-strip electrodes. Using the extended point-matching method, coupled mode theory and electro-optic modulation theory, thorough design and optimization are performed. By introducing the effective applied voltage, formulas of the high-frequency response under skin-effect are deduced, and characteristics under skin-effect are analyzed. Under the central wavelength of 1550 nm, the half-wave voltage is as low as 1.097 V for the device with an active region length about 8.884 mm. Considering the influences of the skin-effect, the 3-dB modulating bandwidth of the microwave signal is up to 94 GHz. A high extinction ratio of more than 20 dB and a low insertion loss of less than 4.18 dB are achieved when the microwave frequency is below 68 GHz under skin-effect. This design technique is proven to be accurate by the comparison with the beam propagation method (BPM). 相似文献
998.
Yuguo Li Ruiqin Peng Xianwu Xiu Xuelei Zheng Xiaosen Zhang Guannan Zhai 《Superlattices and Microstructures》2011,50(5):511-516
Tin oxide (SnO2) nanoparticles were fabricated by evaporation of Sn powers at 1000 °C in air pressure. The as-deposited SnO2 particles were single crystal structure, which were mostly spherical shape, the diameter of particles was ranging from 200 to 600 nm. The photoluminescence (PL) spectrum showed that a sharp emission peak at around 393 nm with the excitation wavelength at 325 nm, which suggested possible applications in nanoscaled optoelectronic devices. It was also found that the holding time affects the morphology of the products. The formation mechanism of SnO2 particles was discussed. 相似文献
999.
1000.
Qingyu Xu Zheng WenJinlong Gao Di WuShaolong Tang Mingxiang Xu 《Physica B: Condensed Matter》2011,406(10):2025-2027
Bi(Fe0.95Co0.05)O3 films were prepared on conductive indium tin oxide (ITO)/glass substrates by chemical solution deposition. Well saturated polarization hysteresis loop has been observed with a remnant polarization value of about 22 μC/cm2 at room temperature. Weak ferromagnetism with saturation magnetization of about 3 emu/cm3 was observed at room temperature. The clear observation of both room temperature ferroelectric and ferromagnetic properties suggests the potential multiferroic applications of Bi(Fe0.95Co0.05)O3. 相似文献