Multiple-Output Fiber-Ring Lasers and Amplifiers in a Hybrid CATV and ADSL Broadcasting Optical Fiber Communication System

In this article we propose two kinds of new fiber ring structure with a semiconductor optical amplifier. The first structure is a one-fiber-ring amplifier with an 8 × 8 fiber coupler and a semiconductor optical amplifier (SOA). The second fiber ring structure is a two-fiber-ring laser including an 8 × 8 fiber coupler, a 2 × 2 E/O modulator, and an SOA. The 14-output spectra of the fiber laser are measured. The gain coefficients of each port of the multiple-output-fiber-ring amplifiers are also measured. We apply these two kinds of fiber ring structures in a hybrid CATV and ADSL broadcasting optical fiber communication system. This application can develop a broadcasting system with large coverage area without using many laser diodes and optical amplifiers. The performance of such a system is also analyzed in this article.     

微量金属元素含量与高胆固醇致病关系的研究

1 对象与方法 1.1 观察对象 住院冠心病人44例,男女各22名,年龄45～77岁,平均62.1岁.临床诊断标准符合WHO标准 ,即典型心绞痛,伴心电图ST段水平下移≥0.05mV,T波倒置.对照组42例,选择经体检,心电图、B超、血脂、血糖、肝、肾功能等各项检查,排除了与心脑血管有关的疾病的健康人 ,并在年龄、性别方面作了适当匹配.     

差动型激光自混合干涉式位移测量系统

提出了一种利用激光自混合干涉效应的差动式位移测量系统, 建立了系统的数学模型,经仿真分析及实验验证表明： 和单激光管结构相比, 该系统位移分辨力提高了二倍, 达 １／４ 光波波长, 且能大大减小光反馈强度引起的噪声及温度干扰。     

PSO萃取色层分离原子发射光谱测定氧化钇中十四个稀土杂质

本将石油亚砜浸渍在一种特制的吸附树脂上,用ＰＳＯ为固定相的萃取色层法分离氧化钇中痕量稀土杂质,可以分析６－７Ｎ级的氧化钇样品,加入试验的回收率为６７－１２０％,相对标准偏左为±４－１９．４％。     

聚碳酸亚丙酯聚氨酯的合成与性能

用ＣＯ２与环氧丙烷共聚产物聚碳酸亚丙酯制备出聚氨酯（ＰＰＣＰＵ）．同时探讨了ＰＰＣＰＵ最佳合成方法,考察了异氰酸酯基与羟基的比值、扩链交联剂用量等因素对其力学性能的影响．研究了ＰＰＣＰＵ的形态结构及其性能对配比的依赖关系．发现聚碳酸亚丙酯的耐热性因聚氨酯的形成而得到较大的改善,并发现该类材料具有优异的耐水性能．     

Pressure-induced emission in 0D metal halide(EATMP)SbBr5 by regulating exciton-phonon coupling

Zero-dimensional(0D)hybrid metal halides are considered as promising light-emitting materials due to their unique broadband emission from self-trapped excitons(STEs).Despite substantial progress in the development of these materials,the photoluminescence quantum yields(PLQY)of hybrid Sb-Br analogs have not fully realized the ca-pabilities of these materials,necessitating a better fundamental understanding of the structure-property relation-ship.Here,we have achieved a pressure-induced emission in 0D(EATMP)SbBr5(EATMP=(2-aminoethyl)trimethylphosphanium)and the underlying mechanisms are investigated using in situ experimental characterization and first-principles calculations.The pressure-induced reduction in the overlap between the STE states and ground states(GSs)results in the suppression of phonon-assisted non-radiative decay.The photoluminescence(PL)evo-lution is systematically demonstrated to be controlled by the pressure-regulated exciton-phonon coupling,which can be quantified using Huang-Rhys factorS.Through detailed studies of the S-PLQY relation in a series of 0D hybrid antimony halides,we establish a quantitative structure-property relationship that regulating S value toward 21 leads to the optimized emission.This work not only sheds light on pressure-induced emission in 0D hybrid metal halides but also provides valuable insights into the design principles for enhancing the PLQY in this class of materials.     

The coordination geometry of water in some salt hydrates

The orientations of water molecules next to metal ions in salt hydrates are useful indications of the orientations which may be expected for water molecules which are next to metal ions in aqueous solution. A survey of the data for the salt hydrates shows that a water molecule may often be tetrahedral (i.e., coordinated to the metal ion, accepting a hydrogen bond from another water molecule, and donating two hydrogen bonds) if it is next to a +1 ion, a+2 ion, or a+3 ion of the rare earth series, although apparently not for smaller +3 ions.     

Conductance behavior of electrolytes in 1,3-dimethylethyleneurea and 1,3-dimethylpropyleneurea at 25°C

1,3-Dimethylethyleneurea (DMEU) and 1,3-dimethylpropyleneurea (DMPU) were investigated as electrolytic media for a number of alkali metal and triisoamylbutylammonium salts via conductivity measurements over a concentration range of 1–100×10^–4 M at 25°C. The data were analyzed by the Fuoss-Shedlovsky, Fuoss-Onsager, and expanded Pitts equations. The limiting equivalent conductivities were about 1.5 times greater in DMEU than in DMPU, which is exactly the ratio of the viscosities. From the Fuoss-Onsager analysis, all salts studied were found to be essentially unassociated in both solvents. From the expanded Pitts equation the extent of association was small, but within a salt series the equation indicated that association decreased in the order iodides, thiocyanates > perchlorate > tetraphenylborates. Neither solvent differentiated between sodium and potassium ion mobilities, indicating a type of solvation behavior different from that in acyclic urea solvents such as tetramethyl- and tetraethylurea.     

Ionization constants for deuterium oxide in deuterium oxide-organic mixtures

A potentiometric method using a glass electrode has been applied to determination of ionization constants for deuterium oxide (D₂O) in binary mixtures of D₂O with dioxane, tetrahydrofuran, acetone, dimethylsulfoxide, CH₃CH₂OD, and CH₃OD at 25°C. The results are compared with values of ionization constants for H₂O obtained previously in the corresponding H₂O-organic mixtures, and the isotope effect is shown to be small. Further calculations with the D₂O results show that the first five solvents mentioned above are neither appreciably acidic nor basic in D₂O solution, but that CH₃OD shows slightly acidic behavior (pK_a=16.0±0.3).