A 1Gb/s silicon photo-receiver in standard CMOS for 850-nm optical communication

A monolithic silicon CMOS optoelectronic integrated circuit (OEIC) was designed and fabricated with standard 0.6 mu m CMOS technology. This OEIC circuit consisted of an integrated double photodiode detector (DPD) and a preamplifier. The DPD detector exhibited high bandwidth by screening the bulk-generated diffusion carriers and suppressing the slow diffusion tail effect. The preamplifier exploited the regulated cascode (RGC) configuration as the input stage of receiver, thus isolating the influence of photodiode capacitance and input parasitic capacitance on bandwidth. Testing results showed that the bandwidth of OEIC was 700MHz, indicating the bit rate of 1Gb/s was achieved.

钨丝掩模二次倾斜离子注入850 nm室温连续垂直腔面发射激光器

采用钨丝做掩模,进行倾斜的离子注入优化电流限制区,制作出室温连续的垂直腔面发射激光器件.该器件的最低阈值电流为1.4 mA,串联电阻约207 Ω, 输出光功率超过1 mW.

七氟丁酸酐有序超薄膜的制备与结构

在涂敷有聚合物PEI涂层的单晶硅表面上制备了HFBA单层分子膜,接触角测量及XPS结果表明,HFBA在PEI表面产生了化学吸附发生了化学键合(酰胺键),形成了低表面能的HFBA单分子层膜.这一吸附反应的动力学行为可能表现为Langmuir单分子层化学吸附.

扩散处理热浸镀铝钢高温抗氧化行为的研究

Effect of diffusion on coating microstructure and oxidation resistance of aluminizing steel

The effect of diffuse treatment on coating microstructure and oxidation resistance at high-temperature of hot-dip aluminum were studied by means of TEM, SEM and XRD. The results show that, the diffusion temperature has significant effect on structure of coatings and its oxidation resistance. After diffusion at 750 degreesC, the coating consists of thick outer surface layer (Fe2Al5+ FeAl2), thin internal layer (FeAl + stripe FeAl2), and its oxidation resistance is poor. After diffusion at 950 degreesC, the outer surface layer is composed of single FeAl2 phase, the internal layer is composed of FeAl phase, and its oxidation resistance declines due to the occurrence of early stage internal oxidation cracks in the coating. After diffusion at 850 degreesC, the outer surface layer becomes thinner and consists of FeAl2 Fe2Al5(small amount), the internal layer becomes thicker and consists of FeAl+spherical FeAl2, and the spheroidized FeAl2 phase in the internal layer and its existing in FeAl phase steadily improve the oxidation resistance of the coating.

Barium-Functionalized Multiwalled Carbon Nanotube Yarns As Low-Work-Function Thermionic Cathodes

Barium-functionalized multiwalled carbon nanotube yarns were fabricated by drawing and twisting multiwalled carbon nanotube forests through a solution containing barium nitrate. After heat activation under vacuum, the functionalized yarns were enriched in barium oxide due to the high surface-to-volume ratio of the nanotubes. The cathodes exhibited good thermionic properties, with a work function as low as 1.73-2.06 eV and thermionic current density that exceeded 185 mA/cm(2) in a field of 850 V/5 mm at 1317 K. The barium-functionalized yarns had high tensile strength of up to 420 MPa and retained strength of similar to 250 MPa after a 2 h activation process. (C) 2008 American Institute of Physics.

洋脊裂谷与上涌流动

<正> 洋脊中轴裂谷是板块的创生边界,多年来一直吸引着地球科学家的注意。但是,对于中轴裂谷的成因,至今没有得到圓满的解释。本文利用我们在文献[1]中所提出的上涌流动模式,算出了裂谷的深度和宽度、裂谷内底宽度等。这些结果均与观测数据符合,从而给出了洋脊中轴裂谷地形的动力学解释。

扩散处理热浸镀铝钢高温抗氧化行为的研究

对经不同扩散工艺处理的热浸镀铝层高温抗氧化性进行了研究,通过SEM、TEM、XRD分析了经扩散处理后,热浸镀铝层高温氧化过程中组织结构的变化情况,分析了热浸镀铝层高温抗氧化性能和微观结构的关系,确定了提高热浸镀铝层高温抗氧化性的适宜扩散温度。结果表明,经750℃扩散处理,热浸镀铝层结构由较厚的外表层(Fe2Al5+FeAl2)及内层(FeAl+条状:FeAl2)组成,条状FeAl2的形成为氧提供了扩散通道,其抗氧化性较差;经950℃扩散处理,镀层外表层变薄,外表层转为单一FeAl2、内层为FeAl,并出现早期内氧化裂纹,其抗氧化性较差:当扩散处理温度为850℃时,镀层外表层变薄,结构转为FeAl2+少量Fe2Al5,而内层增厚,其结构为FeAl+球状FeAl2,而内层FeAl2球化,增强了氧由内层向基体扩散的阻碍作用,使氧只能逐层形成Al2O3+Fe2O3的氧化膜,提高了镀层的高温抗氧化性。

探针移动速度对等离子体射流热流密度测量结果的影响

采用自行研制的中心嵌有铜柱感应件的小尺寸杆状热流探针,在低扰动条件下,对射入大气环境的纯氩层流等离子体射流传向铜探头表面的热流密度进行了动态测量。结果表明,在射流最高温度16500 K、最大轴向速度850 m/s、探针垂直于射流流动方向的移动速度130～260 mm/s的实验参数范围内,随着探针移动速度的提高,测得的热流密度值减小;射流温度和速度越高,探针移动速度对热流密度测量值的影响越大。

Inter-stage line ratio of He- and Li-like Ti emissions for the electron temperature measurement

Under coronal conditions, the steady state rate-equations are used to calculate the inter-stage line ratios between Li-like Is(2)2p(P-2(3/2))-> 1s(2)2s -> ((2) S-1/2) and He-like 1s2p (P-1(1))-> 1s(2) (S-1(0)) transitions for Ti in the electronic temperature ranges from 0.1 keV to 20 keV. The results show that the. temperature sensitivities are higher at the electronic temperature less than 5000 eV and the temperature sensitivities will decrease with the increase of electronic temperature.

钛宝石强激光负载的有机硅复合凝胶增透膜研究

以硅酸四乙酯(TEOS)和甲基三乙氧基硅烷(MTEOS)为前驱材料，用溶胶-凝胶(sol-gel)方法在钛宝石表面制备得到均匀性良好且具有高激光损伤阈值的有机硅复合凝胶增透膜。膜层在钛宝石激光器输出波段(750～850nm)的增透效果显著，其平均透过率超过98．6％；激光破坏阈值为2．2J／cm^2(800nm，300ps)；膜层表面均匀性达到激光波面的要求，在皮秒、飞秒超短脉冲高功率激光领域具有应用价值。溶胶的性能测试结果表明，溶胶粘度和成膜折射率均随溶液中CH3SiO1.5溶胶体含量的增加而增大，而膜

Modified porous silica antireflective coatings with laser damage resistance for Ti:sapphire

Porous SiO2 antireflective (AR) coatings are prepared from the colloidal silica solution modified with methyltriethoxysilane (MTES) based on the sol-gel route. The viscosity of modified silica suspensions changes but their stability keeps when MTES is introduced. The refractive indices of modified coatings vary little after bake treatment from 100 to 150 Celsius. The modified silica coatings on Ti:sapphire crystal, owning good homogeneity, display prominent antireflective effect within the laser output waveband (750-850 nm) of Ti:sapphire lasers, with average transmission above 98.6%, and own laser induced damage thresholds (LIDTs) of more than 2.2 J/cm2 at 800 nm with the pulse duration of 300 ps.