Rhodamine 6G-doped polymer optical fiber amplifiers

Rhodamine 6G-doped step-index polymer optical fiber is fabricated.The characteristics of the am-plification of rhodamine 6G-doped step-index polymer optical fiber amplifier have been studied.Thehigh-gain optical amplification with a tunable wavelength range from 585 to 613 nm is obtained in a step-index polymer optical fiber doped with rhodamine 6G at 10-ppm level,which can be used for broadband amplifiers and tunable lasers.     

Development of 1.3GHz high-T-c rf SQUID

A new high-T_c (HT_c) rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HT_c coplanar superconducting resonator and a large-area HT_c superconducting film concentrator. We have achieved in the 1.3GHz HT_c rf SQUID system a minimal flux noise of 2.5×10^{-5}Φ_0/\sqrt{Hz} and a magnetic field sensitivity of 38fT/\sqrt{Hz} in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm^2 substrate is 1.35mm^2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HT_c rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges.     

EXAFS STUDY OF THE LOCAL STRUCTURE NANOCRYSTALLINE FeZrB(Cu) SOFT MAGNETIC ALLOYS

The changes of local structures around Fe and Zr atoms in the nanocrystalline films of Fe₈₅Zr₉B₆ and Fe₈₄Zr₉B₆ Cu₁ alloys during annealing process were investigated by extended X-ray absorption fine structure (EXAFS) technique. It is confirmed that Zr atoms always exist in amorphous phase and do not dissolve in the bcc α-Fe crystalline phase. The addition of 1 at% Cu lowers the crystallization temperature.     

Ar—HF体系的结构,性质和分析势能函数

利用Ｇａｕｓｓｉａｎ９２程序和ＣＩＤ／６—３１１Ｇ＊方法优化得到ＡｒＨＦ和ＡｒＦＨ两种线性平衡结构，计算出了这两种弱结合分子的结构参数和离解能，并使用该程序和ＭＰ２／６—３１１Ｇ＊方法计算得到它们的力常数。在此基础上，利用多体项展式方法导出ＡｒＨＦ（Ｘ１Σ＋）体系的分析势能函数，得到的势能面正确地再现了ＡｒＨＦ和ＡｒＦＨ两种线性结构，预测出ＡｒＨＦ有Ｃｓ结构存在。     

飞秒激光在掺Nd3+光热敏折变玻璃中写入光波导

利用中心波长1 028nm、重复频率50kHz、脉冲宽度220fs的超短脉冲激光在掺Nd~(3+)光热敏折变玻璃中刻写双线型和压低包层管状波导.研究了激光功率、波导双线间距、管状波导直径对近场模式的影响,得到了两组导光模式较优的波导.利用波导的近场模式强度分布重构了其折射率分布图,得到两类波导最大的折射率增加量分别为+7.0×10~(-4)和+5.5×10~(-4).利用散射法测得双线型波导的传输损耗为1.29dB/cm;通过测量插入损耗得到压低包层管状波导的传输损耗小于1.95dB/cm.利用飞秒激光在掺Nd~(3+)光热敏折变玻璃中直接写入光波导,在集成光学器件上具有广阔的应用前景.     

A Novel Method for PIT Effects Based on Plasmonic Decoupling

A tunable dual-band stop-band THz spectrum can be realized in a hybrid structure, which consists of metal nanoribbon arrays clad by graphene nanoribbons. Dual-band spectra can be controlled separately by the nanoribbon width ω and graphene chemical potential μ_c. We explain that two local plasmonic modes excited at graphene ribbons belong to different gratings, which uncouple with each other by electro-magnetic shielding of the metal ribbons. Furthermore, plasmonic induced transparent(PIT) effects can also be realized by making the two transmission notches close to each other, with better performance than the PIT system based on plasmonic coupling,such as with a larger extinction radio and a tunable transparency window.     

Spatial Characteristics of Thomson Scattering Spectra in Laser and Magnetic Fields

Spatial characteristics of Thomson scattering spectra are studied for an electron moving in the circularly polarized laser field in the presence of a strong uniform magnetic field. The results show that the angular distributions of the spectra with respect to the azimuthal and polar angles exhibit different symmetries, respectively, which depend on the fields and electron parameters sensitively and significantly. Moreover, for relatively large parameters such as high laser intensity, high magnetic resonance parameter as well as large initial momentum of electron, the two lobes in spectra tend to the laser-propagating direction so that the radiation can be collimated in the forward direction. Furthermore, an important finding is that by choosing the appropriate fields and initial momentum of electron, the high frequency part of the Thomson scattering spectra can reach the frequency range of soft x-ray,in which a high radiation power per solid angle as ～10~(11) a.u. can be obtained.     

41个茶花品种基因组DNA傅里叶变换红外光谱

研究的目的是通过全基因组DNA的傅里叶变换红外光谱(FTIR)对41种茶花品种进行聚类分析和品种鉴定。研究发现,41个茶花品种基因组DNA的FTIR光谱不同,方差分析显示,各茶花品种FTIR数据之间的差异显著,因而,红外光谱可以作指纹光谱鉴定茶花。通过系统聚类结合主成分分析,建立了41种茶花品种的标准聚类和识别模型。41种茶花品种基因组DNA样本的平均光谱的聚类正确率为92.68%,品种鉴定准确率为100%。聚类结果表明,在1.0聚类距离,41个山茶品种可分为9个类别,在15.0聚类距离下可分为3个大类。亲缘关系分析表明,滇山茶中的楚雄居群来自楚雄、腾冲和大理。结果表明：基因组DNA的FTIR光谱数据的系统聚类结合主成分分析可用于茶花快速分类和鉴定。     

Condensation Behavior of Ag Aggregates on Liquid Surfaces

We report a condensation behavior of silver aggregates on silicone oil surfaces. The deposited Ag atoms diffuse and aggregate on the oil surface, and then form granular clusters and ramified islands. The apparent Ag coverage of the total area increases linearly with the nominal film thickness h for h 〈 0.9nm. However, the coverage exhibits a fluctuation behavior for 1.0 nm 〈 h〈 2.5 nm. It is found that the anomalous behavior of the coverage is resulted from a characteristic material condensation process in the aggregates.     

立体声技术近年来的进展

本文总结和评论了立体声技术近年来的进展，包括声像定位理论和实验，传统的双通路立体声系统的改进，环绕产系统，高清晰度电视声系统，假头型立体声系统，数字声频技术在立体声的应用等．文中最后还叙述了对立体声今后发展的展望．