DGD包埋—去包埋样品的免疫标记

小鼠膀胱上皮细胞经细胞选择性抽提和ＤＧＤ包埋后，制备超薄切片，并对其进行免疫标记。结果表明，ＤＧＤ包埋－去包埋样品中的ＡＵＭ蛋白仍可特异地被抗体所识别，这一结果为证明小鼠膀胱上皮细胞中由ＡＵＭ蛋白组成的梭形泡以及腔面不对称单位膜结构均与中间纤维相连提高了证据。本文还对ＤＧＤ包埋后样品免疫标记技术进行了讨论。     

应用电镜原位杂交技术与免疫标记技术研究膀胱上皮细胞的分化

本文应用电镜原位杂交技术与免疫标记技术相结合，在超微水平上对ＡＵＭ蛋白及其ｍＲＮＡ在细胞中的分布进行定性与定位的研究。结果显示ＡＵＭ蛋白的基因从小鼠膀胱上皮中间层细胞开始表达，从而为膀胱上皮细胞的分化提供了确凿的证据。     

AUM结构及其与膀胱上皮分化关系的电子显微镜研究

哺乳动物膀胱上皮中存在一种独特的不对称单位膜结构。本文应用多种电镜技术，观察了小鼠和牛的ＡＵＭ的形态结构，并对ＡＵＭ蛋白及其ｍＲＮＡ进行定性与定位研究，在此基础上膀胱上皮细胞分中中ＡＵＭ结构与成分的变化，结果显示：（１）小鼠膀胱上皮中间层细胞开始转录ＡＵＭ的ｍＲＮＡ并释译ＡＵＭ蛋白形成典型的ＡＵＭ结构，而牛只有在表层细胞中表达ＡＵＭ蛋白，它们可能代表两种不同类型的膀胱上皮细胞的终末分化形式。（２）     

双束共蒸发制备Fe－Cu包埋团簇

基于气体聚集（ＧＡ）形成团簇的过程，利用双束蒸发共沉积方法，在室温下成功地制备了Ｆｅ－Ｃｕ纳米磁性包埋团簇样品。对样品的ＴＥＭ／ＥＤ分析表明，平均直径为２０ｎｍ左右的Ｆｅ团簇被Ｃｕ原子所包裹，形成了以Ｆｅ团簇为芯，Ｃｕ原子为壳的良好的芯－壳式包埋结构。     

不对称单位膜的电镜显示

应用多种电镜技术，观察了膀胱上皮细胞不对称单位膜（ＡＵＭ）的形态结构，并对其成份、分布及其与细胞骨架的关系进行了研究。同时针对这一特殊细胞结构在电镜制样方法上也进行了多方面的探索，并取得一些有意义的结果：（１）ＡＵＭ富含带有糖侧链的糖蛋白；（２）小鼠中间层细胞也具有ＡＵＭ结构；（３）ＡＵＭ结构与中间纤维紧密结合。这些结果为研究ＡＵＭ与膀胱上皮细胞分化的关系以及ＡＵＭ的功能提供了新的直观的证据。     

双束共蒸发制备Fe—Cu包埋团簇

基于气体聚集形成团簇的过程，利用双束蒸发共沉积方法，在室温下成功地制备了Ｆｅ－Ｃｕ纳米磁性包埋团簇样品，对样品的ＴＥＭ／ＥＤ分析表明，平均直径为２０ｎｍ左右的Ｆｅ团族被Ｃｕ原子所包裹，形成了以Ｆｅ团簇为芯，Ｃｕ原子为壳的良好的芯－壳式包埋结构。     

膀胱上皮细胞表面糖被的电镜研究

应用电镜钌红染色与植物凝集素标记技术对小鼠和牛的膀胱上皮的糖被及其在发育中的变化进行了研究，结果显示膀胱表层细胞的腔面质膜上存在丰富的糖被结构，其厚度为４０－６０ｎｍ。它可为钌红染色，但对Ｃｏｎ Ａ和ＷＧＡ的标记不敏感。在胚胎发育的早期，膀胱表层细胞可被ＷＧＡ特异标记，但其标记程度随ＡＵＭ蛋白的增加而迅速下降，揭示在发育过程中膀胱上皮腔面质膜的糖被成分可能发生明显的改变。     

FPGA／CPLD结构分析

对ＦＰＧＡ和ＣＰＬＤ进行了比较，并分别对ＦＰＧＡ／ＣＰＬＤ的基本逻辑单元，连线资源和整体结构进行了分析，最后，总结了ＦＰＧＡ／ＣＰＬＤ的发展方向，并提出了发展适合实现ＭＣＵ的专用ＦＰＧＡ结构和相应ＣＡＤ工具的想法。     

纯化的膀胱上皮细胞不对称单位膜的超微结构与成份分析

纯化的膀胱上皮细胞不对称单位膜的超微结构与成份分析粱凤霞丁明孝翟中和孙同天＊（北京大学生命科学学院，＊纽约大学医学院）不对称单位膜（ＡｓｙｍｍｅｔｒｉｃＵｎｉｔＭｅｍｂｒａｎｅ，简称ＡＵＭ）是存在于哺乳动物膀胱上皮细胞中的独特的膜结构。在前人工作的基...     

应用DGD包埋去包埋剂电镜方法研究染色体骨架

我们将染色体骨架制备方法与非树脂包埋去包埋剂超薄切片电镜方法结合起来，直观地显示染色体骨架的内部结构，分离的染色体骨架保持了与正常染色体对应的形状和大小，染色体骨架是一贯穿于整个染色体中的纤维网架结构，而不是位于染色体核心的轴，实验结果表明，ＤＧＤ包埋去包埋剂超薄切片电镜方法是研究染色体骨架微结构的有力手段。     

Multichannel Differential Group Delay Emulation and Compensation via a Phase Pulse Shaper

We developed a differential group delay (DGD) emulator which is based on a high spectral resolution phase pulse shaper. DGD generation has been demonstrated for up to four wavelength channels independently and simultaneously, with DGD accuracy of approximately 1 ps for up to 400-ps DGD range. For each channel, DGD versus frequency profiles can be arbitrarily programmed to user specifications. Multichannel DGD compensation has also been demonstrated using the same setup.     

一种提高40 Gb/s非归零码系统中偏振度椭球对偏振模色散灵敏度的新方法

提出了利用光带阻滤波器提高 4 0Gb/s非归零码系统中偏振度椭球对偏振模色散灵敏度的方法 ,数值研究了不同滤波器带宽对偏振度椭球三个轴长度的影响。结果表明 ,加滤波器后偏振度椭球对差分群时延和主态旋转率的敏感度明显提高 ,考虑到滤波器引入的损耗 ,提出了在最大差分群时延为 2 0ps时滤波器的带宽应限制在 10GHz以下。另外 ,数值结果还表明在滤波器带宽为 10GHz时 ,小于 4 0ps2 的偏振相关色散不会对偏振度椭球三个轴的长度产生明显的影响     

A comparative study of single-section polarization-mode dispersion compensators

This paper shows how to use multiple importance sampling to study the performance of polarization-mode dispersion (PMD) compensators with a single differential group delay (DGD) element. We compute the eye opening penalty margin for compensated and uncompensated systems with outage probabilities of 10/sup -5/ or less with a fraction of the computational cost required by standard Monte Carlo methods. This paper shows that the performance of an optimized compensator with a fixed DGD element is comparable to that of a compensator with a variable DGD element. It also shows that the optimal value of the DGD compensator is two to three times larger than the mean DGD of the transmission line averaged over fiber realizations. This technique can be applied to the optimization of any PMD compensator whose dominant sources of residual penalty are both the DGD and the length of the frequency derivative of the polarization-dispersion vector.     

PMD outage probabilities of optical fiber transmission systems employing bit-to-bit alternate polarization

The impact of differential group delay (DGD), induced by polarization-mode dispersion, on the performance of differential phase-shift keyed and on-off keyed modulation formats employing bit-to-bit alternate polarization (APol) is investigated by means of numerical simulation. Thereby, it is observed that the optical signal-to-noise ratio (OSNR) penalty due to DGD is almost independent of the power splitting ratio between the principal states of polarization (PSP) of a DGD emulator, when APol modulation formats are employed. Although this leads to a higher mean OSNR penalty for a given DGD value compared to conventional modulation formats, it is shown that the allowed mean DGD for required low system outage probabilities does not change significantly.     

Narrow-band measurement of differential group delay by a six-state RF phase-shift technique: 40 fs single-measurement uncertainty

We describe in detail our implementation of a modulation phase shift (MPS) technique for narrow-bandwidth measurement of differential group delay (DGD) and the principal states of polarization (PSP) in optical fibers and components. Our MPS technique involves launching six orthogonal polarization states (as opposed to the four states typically launched) to achieve improved measurement stability. The measurement bandwidth is 4.92 GHz (twice the 2.46 GHz RF modulation frequency), the measurement time is 13 s per point, and the single-measurement uncertainty is better than 40 fs (/spl sim/95% confidence interval) for DGD values from 10 to 1000 fs. We demonstrate that this uncertainty can be greatly improved by averaging, yielding a 9.7 fs uncertainty (95% confidence interval) on a device with 315 fs of DGD. Sources of uncertainty are detailed, including a DGD contribution from the detector itself. Simulations illustrate the uncertainty contribution of multiple DGD elements in series.     

Statistical properties of the DGD in a long-haul optical fiber system with temporally drifting birefringence

Due to the temporal drift of the fiber birefringence in an optical fiber transmission system, the polarization mode dispersion (PMD) effects measured in a time window can be quite different for different time windows of the same duration. Every 10 s for 10 days, the accumulated differential group delay (DGD) was repeatedly measured at 5000 km in a 107-km recirculating loop with loop-synchronous polarization scrambling. In each DGD measurement, the polarization dispersion vector of the 107-km-long fiber was also measured. To model the measured temporal variation of the DGD, two different perturbation algorithms were used to construct random walks through the configuration space of birefringent fibers, where each fiber realization is determined by the standard coarse-step method. With these simulation models, the statistical properties of the spread of the DGD samples over a finite time period were reproduced.     

基于光栅偏振参数的磁场传感方法研究

给出了一种基于光纤光栅中法拉第效应与测量偏振相关参数的直接测量磁场的新方法.在外加磁场作用下,光纤光栅中的法拉第效应导致两个圆偏振光的传播常数发生改变,从而使色散与差分群时延发生改变.仿真结果表明,在外界弱磁场的情况下,磁致双折射与色散和差分群时延之间存在线性关系,利用这个关系可以通过测量光栅的色散和差分群时延来得到磁致双折射的大小,从而推测出外加磁场的大小.实验中得到该方案测量磁场的灵敏度为6.58522e~(-18)m/Gs,利用现有精度为10~(-17)的光矢量分析仪得到最小可测磁场为2Gs.实验与理论吻合较好.     

利用线性啁啾光纤光栅补偿偏振模色散方案的研究

本文提出一种基于线性啁啾光纤光栅补偿偏振模色散的新方案 ,对光纤光栅由于挤压而产生的群时延差进行了理论计算 ,并实验测量了一被挤压的线性啁啾光纤光栅的两偏振方向的群时延曲线 ,测量的结果证明这种方案切实可行 .     

Enhancing the dynamic range and DGD monitoring windows in DOP-based DGD monitors using symmetric and asymmetric partial optical filtering

We propose and demonstrate a new type of degree-of-polarization (DOP)-based differential-group-delay (DGD) monitor using an optical filter such that the DGD monitoring range and DOP dynamic range are dramatically increased. We apply this technique to varying pulsewidth return-to-zero (RZ), carrier-suppressed RZ (CSRZ), and alternate-chirped RZ (ACRZ) signals and show that by optimally setting the position, bandwidth, and shape of a filter, we can double the DGD monitoring range compared to traditional DOP-based DGD monitors. Using our technique, the DGD monitoring ranges for 10, 20, and 40 Gb/s /spl sim/12.5-ps pulsewidth RZ signals are increased by 32, 33, and 12 ps, respectively. We also show that a narrow-band optical filter, offset from the center of the optical spectrum by the bit-rate frequency, can double the dynamic range of DOP-based DGD monitors for non-RZ (NRZ) signals.