Analysis of Metabolites in Allantoic Fluid of Chicken Embryo by 900 MHz NMR Spectroscopy

900 MHz ¹H NMR (nuclear magnetic resonance) spectroscopy was used to analyze metabolites in allantoic fluid of the chicken embryo in the 9th incubation day without any chemical or physical sample separation. The result showed that superhigh spectral dispersion and sensitivity at 900 MHz are useful in directly analyzing a complex mixture, particularly in resolving the overlapped NMR resonances. In this study, we had assigned 61 metabolites and 26 chemical fragments in the allantoic fluid. The relative concentrations of the major metabolites were also measured. Among the assigned metabolites, some were detected by NMR in chicken embryo allantoic fluids for the first time. The biological functions of these compounds were briefly discussed. Authors' address: Maili Liu, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China     

一种新的磷化铟复合沟道高电子迁移率晶体管小信号物理模型

针对磷化铟(InP)复合沟道高电子迁移率晶体管(HEMT)的特点，对常规单沟道HEMT的小信号物理模型进行了修正，提出了一种新的用于复合沟道HEMT的小信号物理模型，用商用器件模拟软件ISE(integrated systems engineering)对其进行了仿真验证，对比了实测和仿真的I-V特性及转移特性曲线，重点研究了在InGaAs/InP双层沟道中考虑量子效应后的电场和电流密度随着不同栅电压的变化趋势，研究结果表明，由于在沟道中存在量子效应，在栅下靠源端低电场区域，电流主要分布在InGaAs沟道 关键词： 高电子迁移率晶体管 复合沟道 物理模型 磷化铟     

哈密顿算符的对角化与能量本征值问题的代数解法

提出了将哈密顿算符对角化的一种方法.围绕一维谐振子讨论了如何将哈密顿算符对角化、引进的是玻色算符还是费米算符的问题,并分析了能量量子化的原因及能量子与声子的区别.     

脉冲磁场处理对碳纳米管掺杂MgB2线材临界电流密度的影响

对碳纳米管(CNT)掺杂MgB₂超导体磁场处理后的行为进行了研究. 结果表明，CNT掺杂MgB₂超导体经5T脉冲磁场处理后临界电流密度J_c(H)在低磁场下提高了2—3倍，高场下提高一个数量级以上，扫描电镜结果显示CNT沿着处理磁场方向规则排列并且成为MgB₂基体的形核中心和高效的磁通钉扎中心. 关键词： 2')" href="#">MgB₂ 碳纳米管 脉冲磁场处理     

Flat-top interleavers with chromatic dispersion compensator based on phase dispersive free space Mach-Zehnder interferometer

In this paper, novel interleavers using circular cavities (CC) in a Mach-Zehnder interferometer (MZI) has been presented and demonstrated for the first time, in which CCs act as phase dispersive mirrors which exhibit a periodic dependence on the frequency of light. Three implementation schemes have been proposed and investigated. Theoretical analysis shows the spectral characteristics of each scheme in a 50-GHz channel spacing application. Furthermore, the chromatic dispersion (CD) of each output comb can be flattened within passband by appending an additional CC. The result shows that the proposed designs with novel interferometer technique can simultaneously provide flat top passbands, high isolation stopband and low CD value as well.     

晶体学与准晶体学点群的母子群关系

依据群论，得出了准晶体学点群的直积或半直积推导算式；依据结晶学理论，绘出了五角、八角、十角和十二角晶系各点群的极赤投影图.据此推导出了每一个准晶体学点群的全部最大子群，从而推导并绘制出了三维晶体学和准晶体学点群之间的母子群关系(60个点群的“家谱”).该“家谱”以最大子群链的图解形式直观地给出了每个点群的最小母群和最大子群. 关键词： 准晶体 晶体 点群 最大子群 最小母群 群链     

新型材料--光子晶体

半个世纪以来，对半导体技术的深入研究和广泛应用推动了电子工业和信息产业的迅速发展。目前半导体技术正向高速度、高集成化方向发展，但这也不可避免地引发了一系列问题，例如电路中能量损耗过大导致集成片发热，如何进一步将电子器件小型化等。人们由此感到半导体器件的能力已基本达到了极限，转而把目光由电子投向了光子，因为光子有着电子所不具备的优势：速度快，彼此间不存在相互作用，一旦实现用光子替代电子传递信息，     

纳米晶ZrO2:Er3+-Yb3+的制备及其室温上转换发射

用化学共沉淀法制备了ZrO₂:Er³⁺-Yb³⁺纳米晶粉体，所制备的纳米晶粉体具有较强的室温上转换发射和红外发射.研究了样品的晶体结构和上转换发光性质随着Yb³⁺掺杂浓度和煅烧温度的变化关系.通过X射线衍射谱分析发现，经800℃煅烧2h后得到的ZrO₂:Er³⁺-Yb³⁺纳米晶是四方相和单斜相的混合结构，经950℃煅烧2h后得到的样品以单斜相为主，随着Y