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Improvement of Low-Frequency Acoustic Spatial Correlation by Frequency-Shift Compensation 总被引:7,自引:0,他引:7 下载免费PDF全文
Interference of normal modes can lead to longitudinal decorrelation of an ocean acoustical field, so It can aecrease the gain of a wide-aperture array. Based on waveguide invariance, we propose a frequency-shift compensation method that can be used to improve the signal correlation received at different locations with certain longitudinal separations. The method is verified by experimental data. 相似文献
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张仁 《广东微量元素科学》2016,(4):57-60
目的分析重度烧伤患者不同营养护理的效果观察,研究重度烧伤患者临床诊疗的医学价值。方法选择鹰潭市解放军第一八四医院2013年5月至2013年9月收治的60例重度烧伤患者为实验对象,将其随机分为实验组(30例)与对照组(30例),对照组患者采用一般饮食护理,实验组患者在对照组的基础上采用肠内营养支持予以护理,观察两组患者接受护理治疗后的实际情况。结果通过比较实验组与对照组患者治疗前后的血红蛋白与血清白蛋白等临床资料,计算两组患者的氮平衡,经过对比与分析后得出结果为:实验组患者的血清白蛋白与氮平衡分别为(45.6±4.1)g/L、(1.54±0.30)g,而对照组患者的血清白蛋白与氮平衡分别为(32.7±3.9)g/L、(0.92±0.30)g,实验组患者的临床治疗效果明显优于对照组,结果差异显著(P0.05),具有统计学意义。结论在重度烧伤患者的临床治疗过程中采用肠内营养支持的护理措施,能够显著提升临床护理的质量,对患者的疾病症状起到有效的控制,降低患者出现并发症状的几率,极大地改善患者的生活质量。 相似文献
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为改善碳纳米管场效应晶体管(CNTFET)器件性能, 提高电子输运效率, 提出了一种异质双金属栅(HDMG)电极结构CNTFET器件. 通过对单金属栅(SMG)-CNTFET器件输运模型的适当修改, 实现了对HDMG-CNTFET器件电子输运特性的研究.研究结果表明, 对于所提出的HDMG结构器件, 如果固定源端金属栅S-gate的功函数WGS使其等于本征CNT 的功函数, 而选取漏端金属栅D-gate的功函数WGd, 使其在一定范围内小于WGS, 可优化器件沟道中的电场分布, 提高器件沟道电子平均输运速率; 同时由于HDMG-CNTFET的D-gate对沟道电势具有调制作用, 使该器件阈值电压降低, 导致在相同的工作电压下, HDMG-CNTFET器件具有更大的通态电流; 而D-gate对漏电压的屏蔽作用又使HDMG-CNTFET与SMG-CNTFET相比具有更好的栅控能力 及减小 漏极感应势垒降低效应、热电子效应和双极导电性等优点. 本研究通过合理选取HDMG-CNTFET双栅电极的功函数, 有效克服了现有研究中存在的改善CNTFET性能需要以减小通态电流为代价的不足, 重要的是提高了器件的电子输运效率, 进而可提高特征频率、减小延迟时间, 有利于将CNTFET器件应用于高速/高频电路.
关键词:
CNTFET
异质双栅
电子输运效率
双极导电性 相似文献
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Ambient noise data measured in an experiment conducted near the sea route are analysed. It is found that at low frequency, the measured horizontal correlation coefficients at different separations oscillate much larger than that predicted by the classical ambient noise model. The theoretical analyses show that the observed phenomenon is mainly caused by windy noise together with the discrete shipping noise nearby. An ambient noise model is proposed to include the effects caused by both the noise sources and can be used to forecast the ambient noise field near a sea route. 相似文献
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We study the relation between the bosonic frequency shift of a dipole oscillation and the fermionic compressibility in a Bose-Fermi super fluid mixture. Our results show that the A transition occurs in such a system, which interprets the perplexing phenomenon observed in the recent experiment [arXiv:1705.04496]. In that experiment,the frequency shift of the bosonic gas was measured with different fermion-fermion s-wave scattering lengths af. The most striking feature of their measurement is that the frequency shift shows a puzzling non-monotonic behavior around 1/kFaf(?)-0.2 with k_F being the Fermi momentum. In the present work, the relation between the bosonic frequency shift and the compressibility of the Fermi gas is revealed by means of the equation of state of the super fluid mixture. Making use of the relation, we find that the compressibility of Fermi gas shows a ∧-like shape around 1/k_Faf(?)-0.2. We would like to stress that no free parameter is used in our calculation and our results can be further testified in a future experiment. 相似文献
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合成了乙烯基咪唑碘盐(VImI)和聚乙二醇单甲醚甲基丙烯酸酯(PEGMA)的梳状共聚物.利用VImI/PEGMA共聚物制备了准固态聚合物电解质.通过光电流密度-电压(J-V)曲线和电导率测定以及电化学阻抗分析,探讨了基于此电解质的染料敏化太阳能电池的电荷传输与界面电子转移机制.结果表明,VImI/PEGMA共聚物可以有效抑制TiO2/电解质界面电子复合并提高TiO2导带能级,敏化电池的光伏性能并不完全取决于电解质的电导率.通过考察共聚物中VImI与PEGMA单元的摩尔比与开路电压的关系,发现共聚物对电子复合的抑制作用主要源于VImI链段.此外,开路电压衰减(OCVD)和瞬态光电流测试结果说明,共聚物能够提高TiO2薄膜的电子寿命,而且对陷阱电子能级的分布具有调节作用.当共聚物在电解质中的质量分数为50%,VImI与PEGMA的摩尔比为5.0时,准固态染料敏化太阳能电池于100mW·cm-2光强下获得了4.10%的光电转换效率. 相似文献
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