共查询到20条相似文献,搜索用时 62 毫秒
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Lasing at 1.3 μ upon flash photolysis of 2-2-2 tri-fluoroethyliodide, CF3 CH2 I, has been observed on the2P_{1/2} -2P_{3/2} magnetic dipole allowed transition of atomic iodine. Using an 800-J flash, a maximum peak power output of approximately 108 W for 10-μs duration at half-maximum intensity was obtained with a pressure of 17 torr CF3 CH2 I. 相似文献
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Dan Terlep 《电子产品世界》2006,(13):94-98
本文提供了混频器的2×2杂散响应与IP2的关系及其在接收机设计中的应用.并以MAX9993有源混频器在UMTSWCDMA系统中的应用为例具体分析IP2与2×2杂散响应的关系. 相似文献
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氟氧化物玻璃陶瓷综合了传统激光晶体和激光玻璃的优点,是近年来激光材料研究的新热点。我们制备了掺杂Er离子的SiO2-Al2O3-PbF2-ZnF2玻璃陶瓷材料,并对其显微结构进行了初步研究。 相似文献
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K. C. Goretta V. R. Todt D. J. Miller M. T. Lanagan Y. L. Chen U. Balachandran J. Guo J. A. Lewis 《Journal of Electronic Materials》1995,24(12):1961-1966
Three methods were used to introduce flux-pinning centers into Bi2Sr2CaCu2Ox (Bi-2212) and TlBa2Ca2Cu3Ox (Tl-1223) samples. It was found that carbon induced local decomposition, that nanosized Al2O3 additions created stable reaction products, and that second phases could be isolated in Tl-1223 during synthesis. Each of
these defects enhanced flux pinning and was of most benefit at temperatures ≤ 35K. 相似文献
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Y. F. Li M. E. Loomans K. C. Goretta S. E. Dorris M. T. Lanagan R. B. Poeppel J. J. Wenzlaff P. M. Winandy C. A. Youngdahl U. Balachandran P. Kostic 《Journal of Electronic Materials》1994,23(11):1163-1167
Three phase assemblages were used to produce Bi2Sr2CaCu2Ox (2212) during sintering: a mixture of 20% Ca-rich 2212+80%2212, partially synthesized 2212, and Bi2Sr2CuOx (2201)+(1/2 Ca2 CuO3+1/2 CuO) (denoted 0011). The mixture of 2201+0011 produced highly pure 2212 within 50 h of heating in air at ≈850°C. Ag tubes
were filled with a mixture of 2201+0011 and worked into tapes by a powder-in-tube process. Heat treatments produced microstructures
consisting of small, highly textured 2212 grains. Tc values were ≈70K. Transport Jc values at 4.2K were ≈104 A/cm2. 相似文献
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Li_2O-B_2O_3-SiO_2掺杂低温烧结CLST陶瓷的介电性能 总被引:3,自引:1,他引:2
通过Li2O-B2O3-SiO(2LBS)玻璃的有效掺杂,低温液相烧结制备了16CaO-9Li2O-12Sm2O3-63TiO(2CLST)陶瓷。研究了LBS掺杂量对其烧结性能、相组成及介电性能的影响。结果表明:通过掺杂LBS,使CLST陶瓷的烧结温度由1300℃降至1000℃,且无第二相生成。随LBS掺杂量的增加,tanδ显著降低,τf趋近于零。当w(LBS)为10%时,CLST陶瓷在1000℃烧结3h获得最佳介电性能:tanδ为0.0045,τf为4×10–6/℃,虽然εr由105.0降至71.0,但仍属于高εr范围。 相似文献
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We performed thermoelectric characterizations on TlCu3Te2: (Tl1+)(Cu1+)3 (Te2−)2 and TlCu2Te2: (Tl1+)(Tl3+)(Cu1+)4(Te2−)4, in order to understand the relationship between the thermoelectric properties (especially the lattice thermal conductivity
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lat) and the valence states of Tl. The thermal conductivity of TlCu2Te2 is high (about 8 W m−1 K−1), while that of TlCu3Te2 is extremely low (around 0.5 W m−1 K−1) like other thallium tellurides. This high κ of TlCu2Te2 was caused not only by its large electronic contribution but also by its intrinsically high κ
lat. The present study implies that the valence states of Tl would play some important roles in determining the magnitude of
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lat. 相似文献
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K. C. Goretta C.-T. Wu M. T. Lanagan R. B. Poeppel J. Schwartz S. Wu 《Journal of Electronic Materials》1993,22(10):1289-1294
Silver-clad tapes with transport Jc values to 105 A/cm2 at T-4.2K were produced by a powder-in-tube process. Moderate reductions per pass and proper tape thicknesses were essential
for producing good conductors. Partial-melt sintering, followed by a solid-state heat treatment, produced microstructures
consisting of large, well-aligned 2212 grains and alkaline-earth cuprate phases. The deleterious effects of these second phases
were minimized by proper heat treatments, but further reductions in the sizes and concentrations of these phases are needed
to improve Jc values substantially. Lithium additions raised Tc, improved flux pinning, and lowered melting points. They offer hope that the presence of alkaline-earth cuprates can be limited
through use of low-temperature heat treatments. 相似文献
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(Li,Nb)掺杂SnO_2压敏材料的电学非线性研究 总被引:2,自引:0,他引:2
研究了掺锂对 Sn O2 压敏电阻器性能的影响。研究发现 L i 对 Sn4 的取代能明显提高陶瓷的烧结速度和致密度 ,且能大幅度改善材料的电学非线性性能。掺入 x(L i2 CO3)为 1.0 %的陶瓷样品具有最高的密度 (ρ=6 .77g/ cm3)、最高的介电常数 (ε=185 1)、最低的视在势垒电场 (EB=6 8.86 V/ mm)和最高的非线性常数 (α=9.9)。对比发现 ,Na 由于具有较大的离子粒半径 ,其掺杂改性性能相对较差。提出了 Sn O2 · L i2 CO3· Nb2 O5晶界缺陷势垒模型 相似文献