The relationship between IR characteristic peak and microstructure of the glass used as optical fiber

Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found that 1 100 cm^-1 characteristic peak shifts to higher wave number when Si-O-Si bond angle increases. Taking fused biconical taper （FBT） coupler as an example, the microstructures of the fiber coupler manufactured at different draw- ing speeds were tested with micro infrared spectrum. According to the test results, it is found that the bond angle at the taper region is the largest, the one at the fused region is the second largest, and the one of bare fiber is the smal- lest. The characteristic peaks of fused-taper region shift to higher wave number when drawing speed increases.     

Novel manufacturing method of optical fiber coupler

Based on the coupling mode theory that the coupling ratio of fiber coupler changes periodically with center distance of two optical fibers, a novel manufacturing method of optical fiber couplers was developed with fused biconical taper experimental system. Its fabrication process is that the fiber is fused but not stretched when light begins to split, and the reduction of diameter of fiber is dependent on the theological characteristic of the fused fiberglass. The performance of the coupler was tested. The results show that the performance of the novel optical fiber coupler meets the performance expectations, and its diameter of coupling region （about 30 μm） is twice as long as that of classical fused biconical taper coupler （about 16 μm）, so the default, that is, the device is easy to fracture, is restrained and the reliability is greatly improved.     

Experimental measurement and numerical analysis of fused taper shape for optical fiber coupler

To find out the effect of the shape of fused taper region on the optical fiber coupler, the fiber couplers were fabricated at different drawing speeds with a six-axes fiber coupler machine. The results, which were obtained fi＇om the shape of fused taper region measured with microscope, show that there is a close correlation between the cone angle and optical performance of fiber coupler. High-performance fiber coupler cannot be obtained until rheological shape is controlled accurately. The numerical analysis model, which was built based on generalized Maxwell viscoelastic theory, is resolved with ANSYS software. The calculated results accord with the experimental data. It can apply a theoretic basis for forecasting the shape of fiber coupler fabricated under the conditions of different technological parameters.     

两种有机锗类化合物的振动光谱

为了研究3-倍半氧锗基-N-(2-苯并噻唑基)丙噻唑(A)和3-倍半氧锗基-2-甲基-N-(2-苯并噻唑基)丙酰胺(B)的结构,采用拉曼散射及红外吸收光谱技术测量了它们的振动光谱.依据分子振动理论,对拉曼光谱和红外吸收光谱的主要峰位进行了振动模式识别,结果显示,在这两种化合物中,Ge-O的伸缩振动都出现在975cm-1...     

侧面级联耦合器对连续光纤激光器的影响

为了研究侧面级联耦合器对光纤激光器的影响,对自主研制的(1+1)×1侧面泵浦耦合器,以及某商品化的(2+1)×1耦合器进行了研究.实验中分别测试了2种耦合器的耦合效率,泵浦光传输损耗,以及信号光泄露等参数,然后用2种结构的耦合器分别搭建了光纤激光器.在耦合器为(1+1)×1结构的激光器中,注入975 nm泵浦功率444 W时,1 080 nm激光功率输出344 W,光-光转换效率77%;在耦合器为(2+1)×1结构的光纤激光器中,当975 nm泵浦功率注入444 W时,1 080 nm激光功率输出260 W,激光器的光-光转换效率59%.对比2种结构的激光器可以看出:对于目前商用的(2+1)×1耦合器来说,由于传输损耗比较大,很难实现级联结构,而实验室自主研制的侧面耦合器能够实现5个级联.     

Effects of sodium hexmetaphosphate on flotation separation of diaspore and kaolinite

1INTRODUCTION ThebauxiteinChinaismainlyofdiasporite type,withhighcontentofAl2O3butlowmassra tioofAl2O3toSiO2.Themainsiliceousminerals ofbauxitearekaolinite,illiteandpyrophyllite[1].Inordertoutilizethebauxiteeffectively,anewflotationdesilication Bayermethodwasdeveloped toproducealumina.Thepurposeofflotationdesil icationistoremovethesilicafromthebauxiteandtoincreasethemassratioofAl2O3toSiO2.Funda mentalresearchofreverseflotationdesilicationhas beenpaidmoreattentionduetoitsadvantageover…     

Effect of technological parameters on optical performance of fiber coupler

To find out the influence of technological parameters on optical performance of fused optical fiber device, the fiber coupler was served as subject investigated by using the fused biconical taper machining as experimental setup. Fused fiber coupler＇s optical performances such as insertion loss, excess loss, directivity and uniformity were tested with the optical test system that was constituted of tunable laser and optical spectrum analyzer. Especially the relationship between optical performance and drawing speed was investigated. The experimental results show that the optical performance is closely related to process conditions. At fused temperature of 1 200℃, there exists a drawing speed of 150μm/s, which makes the device＇s performance optimum. Out of this speed region, the optical performance drops quickly. At drawing speed of 200μm/s, the excess loss is relatively small when the fused temperature is above 1 200 ℃. So the technological parameters have close relationship with optical performance of the coupler, and the good performance coupler can＇t get until the drawing speed and fused temperature match accurately.     

无机阻燃粘胶纤维制备及结构性能研究

采用溶胶凝胶法选用无机阻燃剂硅酸钠制备了无机阻燃粘胶纤维,通过FTIR、SEM、TEM及XRD对阻燃粘胶纤维进行了研究。结果显示：阻燃粘胶纤维在450,800,1060cm叫分别出现了SiO2四面体中Si—O—Si摇摆振动、变曲振动及对称伸缩振动峰;随着阻燃剂加入量的增加,1087和3400cm^-1峰强变强、变宽,表明醇羟基与硅羟基之间有分子间缩合形成新的Si—O—C使阻燃剂与纤维牢固地结合。极限氧指数（LOI）由19提高到了32-42,阻燃效果大大提高;阻燃剂在纤维内部均匀分布;且阻燃剂的加入降低了纤维的结晶性能,纤维的结晶度下降;纤维的强度有所提高。     

STUDY ON Na_2O-GeO_2-SiO_2-PbO GLASSES USED AS THE CLADDING MATERIALS OF HOLLOW WAVEGUIDES FOR TRANSMITTING CO_2 LASER

In this paper a new kind of mid - infrared fiber material is reported. The reflective coefficients (R) of glasses in the system Na2O - ZnO - GeO2-SiO2-PbO have been measured .the refractive index becomes less than unity at 1180 - 900cm-1 range because of the existence of anomalous dispersion. The optical losses of hollow: waveguides were calculated,the predicted losses at 940cm-1are 0. 65 and 0. 081B/ m as the inner diameter of fiber is 0. 5 and 1. 0-mm respectively. The glasses can be used as the cladding materials of hollow waveguides for transmitting CO2 laser from the measurements of characteristic temperatures , coefficient of expansion and chemical durability.     

亚甲基蓝的变温红外光谱研究

亚甲基蓝（Methylene blue,MB）是一种重用的生物染色剂和光敏剂,其分子结构的稳定性直接影响其临床应用效果。本文研究目的是利用红外光谱研究MB在不同温度下分子结构的稳定性。采用KBr压片法测量MB在24℃、37℃、80℃和120℃下的红外光谱,并对红外光谱吸收峰的归属进行详细分析。实验结果表明当温度从24℃逐渐升到80℃时,亚甲基蓝的吸收光谱没有明显变化,其分子结构具有较好的稳定性;当温度升高到120℃时,4 000cm^-1～1 700 cm^-1之间的吸收峰迅速降低,这主要是由于CH、CN、CS键的断裂所致。本文的研究结果将为MB的临床应用提供重要的参考价值.     

预辐照PE接枝PS的制备及性能表征

将聚乙烯（PE）进行预辐照,采用悬浮接枝聚苯乙烯（PS）制备聚乙烯接枝聚苯乙烯（PE-g-PS）。利用红外光谱（FTIR）、核磁共振氢谱（1H-NMR）、X射线光电子能谱（XPS）、扫描电子显微镜（SEM）、差热扫描量热仪（DSC）、击穿场强及流变测试等对PE-g-PS的结构及性能进行表征。结果表明：PE-g-PS的FTIR谱图在1602cm-1,3026cm-1,和3060cm-1处出现明显吸收峰;PE-g-PS的1H-NMR谱图在化学位移为6.5~7.0ppm之间出现了新峰,这是苯环上H的化学位移;证明PS与PE接枝成功。与PE相比,PE-g-PS的结晶温度升高4oC,复合粘度降低,击穿场强提高4.6kv/mm。     

Relationship between rheological manufacturing process and optical performance of optical fiber coupler

Through theoretical analysis and experiments, the viscoelastic mechanical model of optical fiber coupler in the process of fused biconical taper was established, and the numerical analysis in non-uniform temperature field was made. The results show that the rheological parameters, such as drawing speed and fused temperature, have a tremendous influence on stress distribution and performance of optical fiber coupler, especially the influence of fused temperature. The change of fused temperature by 5 ℃ can lead to the change of the maximum stress by 30% and stress difference by 20% in the same cross section. The change of temperature gradient by 3% can result in the change of stress difference by 90%. In the present condition of rheological technology, rheological defects such as crystallizations and microcracks are easy to generate in the optical fiber coupler.     

Infrared Emissivity of La_(0.8)Sr_(0.2)MnO_3 with Three Different Structures

La_(0.8)Sr_(0.2)MnO_3 samples with rhombohedral, orthohombic and monoclinic structures were prepared by solid state reaction, sol-gel and co-precipitation methods, respectively. Lattice parameters, grain size, morphology, infrared absorption and emissivity of samples were investigated. The results indicated that the average crystallite size calculated from XRD result and particle size of orthohombic sample were smaller than those of the other two samples, and honeycomb shape grains were observed in orthohombic sample. Due to lower crystal symmetry, Mn-O stretching vibration peaks of the three samples shifted to higher infrared wavenumber. According to the theory of wave optics and Kirchhoff law, bigger rhombohedral sample showed higher emissivity than monoclinic one. However, due to the honeycomb structure of orthohombic sample, repeated reflection and scattering led to the increase of absorption, and orthohombic sample exhibited the highest emissivity.     

掺钕钇铝石榴石纳米粉体的合成与表征

采用碳酸盐共沉淀法制备掺钕钇铝石榴石纳米粉体,利用XRD、SEM和荧光光谱等测试手段分析了钕钇铝石榴石纳米粉体的物相结构和光谱特性。结果表明:在1100℃和pH=7时,合成质量较好的YAG纳米粉体,颗径尺寸大约为80nm。在508cm~(-1)、566cm~(-1)、690cm~(-1)、720cm~(-1)、785cm~(-1)附近的一系列吸收峰均为YAG中晶格振动与光子相互作用所引起的,在808nm激发下获得了最佳掺杂浓度。     

有限元法分析非对称光纤耦合器波导

用有限元法分析了非对称光纤耦合器波导的场特性.利用自适应法划分有限元三角形格子,计算出在不同结构下最低阶的4个模式的传播常数.数值结果表明,组成耦合器的光纤半径比对偶模和奇模的传播常数都有明显的影响.与奇模不同的是,偶模传播常数对两光纤熔融程度不敏感.     

Infrared Emissivity of La<Subscript>0.8</Subscript>Sr<Subscript>0.2</Subscript>MnO<Subscript>3</Subscript> with Three Different Structures

La_0.8Sr_0.2MnO₃ samples with rhombohedral, orthohombic and monoclinic structures were prepared by solid state reaction, sol-gel and co-precipitation methods, respectively. Lattice parameters, grain size, morphology, infrared absorption and emissivity of samples were investigated. The results indicated that the average crystallite size calculated from XRD result and particle size of orthohombic sample were smaller than those of the other two samples, and honeycomb shape grains were observed in orthohombic sample. Due to lower crystal symmetry, Mn-O stretching vibration peaks of the three samples shifted to higher infrared wavenumber. According to the theory of wave optics and Kirchhoff law, bigger rhombohedral sample showed higher emissivity than monoclinic one. However, due to the honeycomb structure of orthohombic sample, repeated reflection and scattering led to the increase of absorption, and orthohombic sample exhibited the highest emissivity.     

磷灰石振动光谱的研究现状

综述了近年来磷灰石红外和拉曼光谱的研究现状.根据因子群和位置群分析, 磷灰石中的磷氧四面体, 通道羟基,以及外晶格的红外和拉曼活性振动模式数分别为9,15;3,4; 和8,14个.理论预测的模式在实测的谱图中得到证实.磷氧四面体的振动特征强烈地受到四面体畸变的影响,随着畸变加大, 谱带加宽并向低频区规律性位移. 而四面体位置上的畸变也使因子群和位置群分裂值明显增加.结构通道中,随着羟基被氟的替换, 羟基的伸缩与摆动模式频率分别向低频与高频区位移,可据此对结构羟基含量进行间接测定.外晶格的拉曼振动频率一般在400 cm-1以下, 它们可以提供钙位离子的替换信息.常见的四面体替换离子如CO32-, SiO44-, 和 SO42-等的振动光谱特征则表明, 这些离子往往同时进入结构,对磷酸根离子进行耦合替换. 根据红外吸收特点, 可以确定碳酸根离子的结构占位.振动光谱不但是对磷灰石进行物相鉴定的一种技术方法,而且是重要的晶体化学研究手段.     

微氮直拉硅单晶中的原生氧沉淀

本文利用红外光谱技术研究了氮保护气氛下生长直拉微氮硅单晶中原生氧沉淀．研究发现，微氮硅单晶中除了有和１２２４ｃｍ－１红外吸收峰相对应的ａ。方石英原生氧沉淀外，还存在和１０２６，１０１４，９９６和８０１ｃｍ－１红外吸收峰相对应的氧氮复合体的原生氧沉淀．实验还研究了原生氧沉淀在微力硅单晶中的分布，以及和氧碳氢杂质的关系，进一步指出，上述除１２２４ｃｍ－１之外的红外吸收峰，并不是某一种氧现复合体的振动吸收，而是对应着几种不同形态的氧氨复合体。     

Influences of polishing on return loss of optical fiber connectors

With Al2O3 and SiO2 as polishing medium, under different polishing conditions, e.g. with different polishing pressure, polishing time and polishing fluid, the influences of polishing treatment on the return loss of optical fiber connectors were investigated. The return loss of optical fiber connectors is 32-38 dB before polishing. The resuits show that dry polishing(i, e. no polishing fluid) with Al2O3 has less influence on return loss of optical fiber connectors, while dry polishing with SiO2 reduces return loss to about 20dB because of the end-face of optical fiber contaminated. The wet polishing(i, e. using distilled water as polishing fluid) with Al2O3 or SiO2 can increase return loss to 45-50dB, but wet polishing with Al2O3 may produce optical fiber undercut depth of 80-140nm. Wet polishing with SiO2 should be preferentially selected for optical fiber connectors and polishing time should be controlled within 20-30s.     

Structure characterization of F-doped silica glass

Pure and fluorine-doped silica glass were fabricated by plasma chemical vapour deposition (PCVD) and characterized using Raman and infrared spectrum. The change in Raman intensity of 945 cm⁻¹ peak, relating to ≡Si—F stretching vibration, agrees with the change of F content. Compared with measured wavenumber in IR spectrum, the calculated absorption wavelength confirms the incorporation form of F into the glass, the detail of which is a tetrahedron with a Si atom in the center coupled with one F atom and three network O atoms. Such structure identification may be useful for explaining some properties of F-doping silica glass.