多层透射式光纤氢气传感器的氢敏光谱特性

针对多层透射式光纤氢气(H₂)传感器其特殊的多层结构造成了类似于F-P 腔 效应的周期性光谱特性变化尚未可知问题,构建了一种适用于多层 透射式探头的原位H₂敏光谱观测系统,通过实验研究了在不同H₂浓度下这种多层膜 结构的光谱特性, 讨论了光源波长变化对传感器测量稳定性的影响规律,为进一步提高传感器性能奠定了实 验基础。实验 结果表明,光源波长变化对传感器测量的可靠性有显著影响,但是通过扫描波长的方式测 量可以有效避免这类H₂传感器的波长漂移问题,达到较高的测量可靠性。     

一种二次镀银光纤光栅气敏传感器

为了更加有效地实时检测井下硫化氢(H₂S)气体,提出一种在光纤Bragg光栅(FBG)上二次 涂镀银(Ag)膜的光纤气敏传感器。一方面,采用二次镀Ag的制备方法增加Ag膜的均匀性,提 高气敏元件的灵敏度;另一方面,采用特殊的油气分离、流线型设计,保证了H₂S气体与 气敏元件的有效接触,实 现井下低浓度气体的实时检测。根据实验,当镀Ag的FBG气敏元件置于H₂S气体中时,传入 光 纤的倏逝波能量减小,反射光谱的峰值功率下降2.0dBm。     

PEI/PMMA共混有机聚合物的成膜性和对硫化氢气体的响应

采用主客掺杂的方法制备PEI/PMMA共混有机聚合 物,并采用旋涂的方法研究了共混有机聚合物的成膜特性,包括薄膜厚度、平整度与旋涂薄 膜转速的关系,测量发现匀胶机 转速越高薄膜厚度越均匀,高速为1500r/min 时薄膜最大厚度差为0.626μm。有机聚合物 薄 膜的紫外透过光谱表明共混有机聚合物所成的薄膜对H₂S气体有良好的响应,当混合液中 含有0.04g的PEI时,紫外透射率由86.81%下 降到55.54%,非常明显。紫外吸收光谱表明 薄膜和低浓度H₂S气体的反应不明显,但是对高浓度的H₂S有响应。通过高温处理与H₂S气体反应后的薄膜,可以增大薄膜的紫外吸收强度。     

一种基于Pd-Y合金纳米膜的光纤H2传感器

为提高光纤H₂传感器的响应速度、稳定性和可 重 复性,本文分析了Pd-H传感机理,进而提出利用双靶溅射工艺在石英光学玻璃基底上制 备55nm厚的Pd-Y合金H₂敏薄膜,采用双光路 检测技术设计并实现了反射式光纤束H₂传感器系统。通、放H₂实验结果表明,本文 研制的基于Pd-Y合金纳米薄膜的 传感器具有响应快速的特点,特别是在多次循环老化实验后表现出良好的稳定性和可重复性 。     

基于光声光谱的二氧化碳测量技术研究

光声光谱技术是一种以光声效应为基础,具有响 应速度快、测量时间短、检测灵敏度 高等优点的新型光谱分析检测技术,已成为一种快速、安全、可靠的痕量气体检测手段。本 文利用中心波长位于2.0 μm的分布反馈式可调谐二极管激光器作为 光源,搭建了二氧化碳(C O₂)光声光谱测量系统,实验中采用对样品气体加湿的方式,通过引入弛豫速率快的H₂O 分子 有效降低CO₂分子的弛豫时间,增加了CO₂气体的光声信号强度,提高了系统的探测灵敏 度。 测量中选取4998.35 cm－1处的CO₂吸 收谱线为研究对象,结合波长调制技术,对CO₂气体进 行了探测研究。首先通过对系统的评估,确定了系统的最佳调制频率和最佳调制振幅为785 Hz和7.586 cm－1。然后通过对一系列 不同浓度的CO₂-N₂混合样品气体在最优实验条件下的测 量研究发现,所测光声信号与CO₂气体浓度之间具有良好的线性关系,进而反演出大气中C O₂气体的含量,其浓度值约为3.82×10－4。最后利用此系统对 室外大气中CO₂含量进行了连续 24小时的连续实时测量,得到了CO₂气体在一天中的浓度变化情况,并利用Allan方差对系 统 的长期稳定性进行了分析,当系统平均时间为1000 s时,探测灵敏度 约为1×10－7,证实了系统具有良好的稳定性和探测灵敏度。     

一种中红外差分甲烷检测仪的研制

根据甲烷(CH₄)分子在中红外波段的吸收特 性并利用宽光谱红外热辐射光源(IR55), 研制了一种基于中红外吸收光谱技术的双通道差分CH₄检测仪。通 过对双通道探测器(3.31 μm和3.90μm)输 出的两路信号进行差分处理,有效抑制了系 统噪声。给出了系统的检测原理和结构,表征了光源和探测器的光学特性。为了提高聚光效 率并增大光程,设计制作了球面反射镜开放气室,其半径约20cm。 配备了16种不同浓 度的CH₄气体样品,开展了气体标定实验,得到了气体浓度 与双通道信号幅值电压的关 系表 达式。 误差实验结果显示, 对16种气体样品的检测误差小于12.4%。 对体积分数为 5×10－4的CH₄气体样品开展的长达10h的浓度测量实验 表明,检测结果的相对波动范围 为±10%。对测得的实验结果进行数理统计,其标准差为2.06×10－5,进而得到该检测仪的检测下限约为6.18×10－5。     

SO2-4/Bi2O3固体超酸的制备及其可见光催化性能

采用水热法结合H2SO4浸泡处理成功合成了SO^2-₄/Bi₂O₃可见光催化材料, 并采用XRD、TG DTA和UV Vis等对合成产物的物相结构、热化学性能、光吸收性能以及可见光催化性能进行了研究, 对H2SO4浸泡工艺条件对产物的可见光催化性能的影响进行了探讨。研究表明, 水热合成产物为α-Bi₂O₃、Bi₂O₄和Bi₂O₂CO₃的混合物, 其中α-Bi₂O₃为主要成分;H₂SO₄浸泡处理并未改变产物的物相结构, 但经H₂SO₄浸泡处理后产物的光催化性能得到了显著的提高, 并且H₂SO₄浸泡工艺条件对产物的光催化活性有着重要的影响。在实验范围内, 在浓度为0.5mol·L^-1的H₂SO₄溶液中浸泡75min, 再经700℃热处理4h可制备出具有较佳光催化活性的产物, 经75min可见光的照射后对甲基橙溶液的光催化脱色率可达93.1%。     

基于虚拟信号处理平台的差分式中红外甲烷检测系统

利用上位机及Labview工作平台数据处理能力强 的优势,实现了一种针对甲烷(CH₄)气体的双通道差分式中红外检测系统。采用IRGJ型双 通道传感器(英国E2V公司,3.31μm 和3.90μm)检测气体浓度变化,利用Labview和数据采集(DAQ)卡(PCI6221)实现对探测器输出 信号的采集和处理,采用二阶巴特沃斯数字滤波器滤除噪声以提高信噪比(S NR),对系统硬件和软 件进行了集成。系统具有信号采集、滤波、幅值提取、浓度计算、存储及网络发布等功能 。 配备了不同浓度的CH₄气体样品,开展了标定实验,并测量了系统的精度、稳定性和检 测下限等指标。实验结果显示,系统对CH₄气体的测量范围为0~5%,对9种气体样品的 检测误差均小于6%。受传感器自身光程的限制,系统的检测下限约为60×10－6。对浓度为 2000×10－6(0.2%)的气体进行了 长达4h的浓度检测,除个别突变点外 ,检测的最大误差小于10%。由于数据处理能力强,系统功能不受资 源限制并可任意扩展。     

用溶胶-凝胶法制备的Cu2Bi2Cr2O8薄膜 及其光学和铁磁性能研究

以硝酸铜Cu(NO₃)₂·3H₂O、硝酸铬Cr(NO₃)₃·9H₂O、硝酸铋Bi(NO₃)₃·3H₂O和乙二醇为原料,利用溶胶-凝胶工艺在石英衬底上制备了纳米Cu₂Bi₂Cr₂O₈薄膜。通过X射线衍射(X-Ray Diffraction, XRD)和拉曼测试对样品进行了表征。结果表明,Cu₂Bi₂Cr₂O₈薄膜具有良好的光学特性,其禁带宽度为1.49 eV;在磁性测试方面,Cu₂Bi₂Cr₂O₈薄膜呈现出了良好的铁磁性。     

用热蒸发法制备的Cu2ZnSnS4 薄膜的光电性能

在室温下用真空热蒸发法在玻璃基片上制备Sn/Cu/ZnS 前躯体膜层,然后对其在550C 下在硫气氛中硫化3小时以制得Cu₂ZnSnS₄ (CZTS) 多晶薄膜。对该薄膜进行X射线衍射（XRD）、能量色散X射线光谱（EDX）、紫外可见近红外分光光度计、霍尔测量系统和3D光学显微镜等分析测试。实验结果表明,当[Cu]/([Zn] [Sn]) =0.83和[Zn]/[Sn] =1.15时,该CZTS薄膜在光子能量范围在1.5 - 3.5 eV 时其吸收系数大于4.010₄cm_-1 ,直接带隙为1.47 eV。其载流子浓度、电阻率和迁移率分别为7.9710₁₆ cm_-3, 6.06 Ω.cm, 12.9 cm₂/(V.s), 导电类型为p型。因此,所制备出的CZTS 薄膜适合作为太阳电池的吸收层材料。     

VOLTE容灾机制研究及优化方案

_{本文首先对VOLTE现网网络结构及容灾机制进行研究分析,发现现存容灾机制中存在的缺点和不确定性,针对其中的问题,针对性地进行了深入研究和分析,创新的提出了1种快速容灾抢通方案,以达到提升VOLTE业务运维能力和用户业务感知的目的。}     

Calculation of energy band gaps in quaternary iii/v alloys

The dielectric theory of electronegativity is applied to the calculation of the compositional dependence of the energy band gap for quaternary III/V alloys of type A_l-xB_xC_1-yD_y and A_1-x-yB_xC_yD. The departure from linearity of E_G versus x and y is taken to be the sum of two terms, the intrinsic or virtual crystal term and the extrinsic term due to effects of aperiodicity which for one type of alloy may occur on both sublattices. Rather than simply treating the quaternary as an average of the bounding ternary systems, as has been common in the past, the intrinsic departure from linearity is calculated by assuming E_h,i,C, and D_av to vary linearly with x and y. The result is a smaller intrinsic deviation from linearity and a much better fit to existing data in the system Ga_1-xIn_xAs_1-y P_y. The calculation is also applied to three systems where no data exist but which are of great interest because of their potential application for the fabrication of lattice matched tandem solar cells: Ga_l-xA1_xAs_l-ySb_y. Ga_1-x-yA1_xIn_yAs, and GaAs_1-x-yP_xSb_y.     

新形势下河北移动全业务支撑策略研究

随着铁塔公司的成立及国家在“宽带中国”“提速降费”等一系列通信领域的重大战略实施,全业务运营越来越成为河北移动保持领先,实现卓越的重要支点。基于此河北移动启动大规模综合业务区建设,由传统传输网围绕基站建设转向全业务支撑。河北移动将综合业务区建设与全业务机房的选取统筹安排,建设综合业务区与全业务机房的联络光缆,将综合业务区光缆网成为承载重要集客数据专线和4G拉远站的载体,合理、有序、迅速实现“一张光缆网”的建设,鼎力支撑全业务及4G的发展。     

Nickel silicidation techniques for strained Si1?xGex, Si1?x?yGexCy, and Si1?yCy alloys material-device applications

A nickel silicide process for Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy materials compatible with Si technology has been developed. Low-resistivity-phase (12–20 μΘ cm) nickel silicides have been obtained for these alloys with different low sheet-resistance temperature windows. The study shows that thin (15–18 nm) silicide layers with high crystalline quality, smooth silicide surface, and smooth interface between silicide and the underlying material are achievable. The technique could be used to combine the benefits of Ni silicide and Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloys. The technique is promising for Si or Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy-based metal-oxide semiconductor, field-effect transistors (MOSFETs) or other device applications.     

Transport properties of thermoelectric materials for coolers

The Seebeck coefficient, thermal conductivity, electrical conductivity and Hall coefficient of cooler grade, p-and n-type ternary alloys of Bi₂Te₃-Sb₂Te₃-Sb₂Se₃ were measured between 10 and 300 K. Between 300 K and about 150 K the temperature dependence of the transport properties can be explained by assuming nondegeneracy and a lattice scattering mechanism. The difference between the temperature dependence of the Hall effect in n-and p-type alloys can be explained by the presence of sub-bands of light and heavy holes in the valence band of p-type alloys.     

Low pressure metalorganic chemical vapor deposition of InP and related compounds

The low pressure metalorganic chemical vapor deposition epitaxial growth and characterization of InP, Ga_0.47In_0.53 As and Ga_xIn_1-xAs_yP_1-y, lattice-matched to InP substrate are described. The layers were found to have the same etch pit density (EPD) as the substrate. The best mobility obtained for InP was 5300 cm² V⁻¹S⁻¹ at 300 K and 58 900 cm² V⁻¹ S⁻¹ at 77₂K, and for GaInAs was 11900 cm² V⁻¹ S⁻¹ at 300 K, 54 600 cm² V⁻¹ S⁻¹ at 77 K and 90 000 cm V⁻¹S⁻¹ at 2°K. We report the first successful growth of a GaInAs-InP superlattice and the enhanced mobility of a two dimensional electron gas at a GaInAs -InP heterojunction grown by LP-MO CVD. LP MO CVD material has been used for GaInAsPInP, DH lasers emitting at 1.3 um and 1.5 um. These devices exhibit a low threshold current, a slightly higher than liquid phase epitaxy devices and a high differential quantum efficiency of 60%. Fundamental transverse mode oscillation has been achieved up to a power outpout of 10 mW. Threshold currents as low as 200 mA dc have been measured for devices with a stripe width of 9 um and a cavity length of 300 um for emission at 1.5 um. Values of T in the range 64–80 C have been obtained. Preliminary life testing has been carried out at room temperature on a few laser diodes (λ = 1.5μm). Operation at constant current for severalthousand hours has been achieved with no change in the threshold current.     

Co3O4/Fe2O3异质结复合材料的制备及其紫外光光电探测性能

分别采用旋涂法和水热法在FTO衬底上制备Co₃O₄种子层和Co₃O₄薄膜,再在Co₃O₄薄膜上水热生长Fe₂O₃纳米棒,获得了高质量的Co₃O₄/Fe₂O₃异质结复合材料。通过改变Fe₂O₃前驱体溶液浓度来改变异质结复合材料中Fe₂O₃组分的含量。结果表明,Fe₂O₃纳米棒覆盖在呈网状结构的Co₃O₄薄膜上,随着Fe₂O₃前驱体溶液浓度即Fe₂O₃组分含量的增加,Co₃O₄/Fe₂O₃异质结复合材料对紫外光的响应逐渐增强,当Fe₂O₃前驱体溶液浓度为0.015mol/L时,异质结复合材料有着很好的光电稳定性,并表现出较高的响应率(12.5mA/W)和探测率(4.4×10¹⁰Jones)。     

Characterization of a rapid thermal anneal TiNxOy/TiSi2 contact barrier

In this paper, the physical and electrical properties of a TiN_xO_y/TiSi₂ dual layer contact barrier are reported. The TiN_xO_y/TiSi₂ barrier was formed by rapidly annealing a Ti thin film on Si in an N₂ ambient. During this process, the Ti film surface reacts with N₂ to form a TiN_xO_y skin layer and the bulk of the Ti film reacts with Si to form an underlying TiSi₂ layer. The influences of rapid thermal anneal (RTA) conditions on the TiN_xO_y layer were investigated by varying the RTA temperature from 600 to 1100° C and cycle duration from 30 to 100 s. It is found that the resulting TiN_xO_y and TiSi₂ layer thicknesses are dependent on RTA temperature and the starting Ti thickness. For a starting Ti thickness of 500Å, 150Å thick TiN_xO_y and 800Å thick TiSi₂ are obtained after an RTA at 900° C for 30 s. The TiN_xO_y thickness is limited by a fast diffusion of Si into Ti to form TiSi₂. When a Ti film is deposited on SiO₂, Ti starts to react with SiO₂ from 600° C and a significant reduction of the SiO₂ thickness is observed after an RTA at 900° C. The resulting layer is composed of a surface TiN_xO_y layer followed by a complex layer of titanium oxide and titanium suicide. In addition, when Ti is depos-ited on TiSi₂, thicker TiN_xO_y and TiSi₂ layers are obtained after RTA. This is because the TiSi₂ layer retards the diffusion of Si from the underlying substrate into the Ti layer. NMOSFETs were fabricated using the TiN_xO_y/TiSi₂ as a contact barrier formed by RTA at 900° C for 30 s and a significant reduction of contact resistance was obtained. In addition, electromigration test at a high current density indicated that a significant improvement in mean time to failure (MTF) has been obtained with the barrier.     

Processing of large YBa2 Cu3Ox domains for levitation applications by a Nd1+x Ba2−x Cu3 Oy-Seeded melt-growth technique

YBa₂Cu₃O_x domains for levitation applications have been produced by a seeding technology that includes Nd_1+x Ba_2−x Cu₃O_y seeds and melt-processing technologies such as conventional melt-textured growth, melt-texturing with PtO₂ and Y₂BaCuO₅ additions, and the new solid-liquid-melt-growth technology. Large domains (∼20 mm) with high levitation forces (F₁ up to 8.2 N) have been produced. The reproducibility of the results is good, and the capability of producing a large number of pellets in a single batch indicates good potential for the production of large amounts of this material.     

基于InP衬底的晶格失配In0.68Ga0.32As的MOCVD生长及其特性研究

采用MOCVD生长技术在InP衬底上成功实现了晶格失配的3μm In0.68 Ga0.32As薄膜生长.通过As组分的改变,利用张应变和压应变交替补偿的InAsxP1-x应变缓冲层结构来释放由于晶格失配所产生的应力,在InP衬底上得到了与In0.68Ga0.32 As晶格匹配的InAsxP1-x“虚拟”衬底,通过对缓冲层厚度的优化,使应力能够在“虚拟”衬底上完全豫弛.通过原子力显微镜(AFM)、高分辨XRD、透射电镜(TEM)和光致发光(PL)等测试分析表明,这种释放应力的方法能够有效提高In0.68 Ga0.32 As外延层的晶体质量.