Application of the fractional Fourier transform to the design of LCOS based optical interconnects and fiber switches

It is shown that reflective liquid crystal on silicon (LCOS) spatial light modulator (SLM) based interconnects or fiber switches that use defocus to reduce crosstalk can be evaluated and optimized using a fractional Fourier transform if certain optical symmetry conditions are met. Theoretically the maximum allowable linear hologram phase error compared to a Fourier switch is increased by a factor of six before the target crosstalk for telecom applications of -40 dB is exceeded. A Gerchberg-Saxton algorithm incorporating a fractional Fourier transform modified for use with a reflective LCOS SLM is used to optimize multi-casting holograms in a prototype telecom switch. Experiments are in close agreement to predicted performance. © 2012 Optical Society of America.

I did that! Measuring users' experience of agency in their own actions

Cognitive neuroscience defines the sense of agency as the experience of controlling one's own actions and, through this control, affecting the external world. We believe that the sense of personal agency is a key factor in how people experience interactions with technology. This paper draws on theoretical perspectives in cognitive neuroscience and describes two implicit methods through which personal agency can be empirically investigated. We report two experiments applying these methods to HCI problems. One shows that a new input modality - skin-based interaction - can substantially increase users' sense of agency. The second demonstrates that variations in the parameters of assistance techniques such as predictive mouse acceleration can have a significant impact on users' sense of agency. The methods presented provide designers with new ways of evaluating and refining empowering interaction techniques and interfaces, in which users experience an instinctive sense of control and ownership over their actions. Copyright 2012 ACM.

Use of wavefront encoding in optical interconnects and fiber switches for cross talk mitigation

A technique of cross talk mitigation developed for liquid crystal on silicon spatial light modulator based optical interconnects and fiber switches is demonstrated. By purposefully introducing an appropriate aberration into the system, it is possible to reduce the worst-case cross talk by over 10 dB compared to conventional Fourier-transform-based designs. Tests at a wavelength of 674nm validate this approach, and show that there is no noticeable reduction in diffraction efficiency. A 27% spot increase in beam diameter is observed, which is predicted to reduce at longer datacom and telecom wavelengths. © 2012 Optical Society of America.

鱼类寄生六鞭毛虫五新种(英文)

六鞭毛科 (Hexamitidae)属动鞭纲 (Zoomastigophorea)、双体目 (Diplomonadida)。自Moore首次报道寄生于鱼类的六鞭毛虫始 ,到目前为止 ,已报道寄生于鱼类的六鞭毛虫 ,共计 30余种 ,分别隶属于六鞭毛虫属 (Hexamita)和旋核鞭毛虫属 (Spironucleus)。作者发现五新种 ,它们是寄生于细鳞斜颌鲴 (XenocyprismicrolepisBleeker)的关桥六鞭毛虫 (Hexamitaguanqiaoensissp .nov.)、寄生于黄尾

Shape signifiers for control of a low-order compressor model

Rotating stall and surge, two instability mechanisms limiting the performance of aeroengines compressors, are studied on the third-order Moore-Greitzer model. The skewness of the compressor characteristic, a single parameter shape signifier, is shown to determine the key qualitative properties of feedback control.

南极鱼两种寄生海蛭的研究

从南极海纽喀姆湾(南纬66°17′,东经110°32′)的南极鱼属Notothenia鱼体上得到两个海蛭标本。经鉴定为多皱海蛭Pontobdella rugosa Moore,1938和椎蛭属Notobdella的一新种。前者的环带后区环的分割明显并因许多大、小结节变得崎岖不平。在一完全体节(ⅫⅠ-ⅩⅫⅠ)里环的通常大小关系是8_2(?)a_1>b_5=b_(60)扭椎蛭新种Notobdella streptocheles sp.nov.呈S形弯曲井从稍膨大的中部向两端渐渐变细。在前吸盘上没有眼。尾吸盘与

牛蛭属一新种记述(蛭纲:医蛭科)

医蛭科牛蛭属Poecilobdella在我国主要分布在广东、广西、云南和台湾。Moore(1930)报道有一种菲牛蛭P.manillensis曾在南京发见,但未附图,也未描述其特征。另据胡经甫(Wu,1930;48)记载有一种颗粒牛蛭P.granulosa分布于北京、苏州和福建。然而陈义(1962)和宋大祥等(1977)报道,他们未在这些地区采到牛蛭属的标本,因此这是有待进一步弄清的问题。笔者于1979年5至6月先后从武昌东湖以及毗邻安徽省的黄梅县各获得牛蛭属标本一条。经过详细地活体观察以及内部解剖,並与

Demonstration of multi-casting in a 1 × 9 LCOS wavelength selective switch

A multi-functional 1 × 9 wavelength selective switch based on liquid crystal on silicon (LCOS) spatial light modulator technology and anamorphic optics was tested at a channel spacing of 100 and 200 GHz, including dynamic data measurements on both single beam deflection and multi-casting to two ports. The multi-casting holograms were optimized using a modified Gerchberg-Saxton routine to design the core hologram, followed by a simulated annealing routine to reduce crosstalk at non-switched ports. The effect of clamping the magnitude of phase changes between neighboring pixels during optimization was investigated, with experimental results for multi-casting to two ports resulting in a signal insertion loss of-7.6 dB normalized to single port deflection, a uniformity of ±0.6%, and a worst case crosstalk of-19.4 dB, which can all be improved further by using a better anti-reflection coating on the LCOS SLM coverplate and other measures. © 2013 IEEE.

The use of wavefront encoding to reduce crosstalk in a multicasting fiber telecom switch

A multicasting fiber optic switch employing a liquid crystal on silicon spatial light modulator is used to demonstrate wavefront encoding, a novel technique for crosstalk mitigation. Experimentally we reduce worst case crosstalk by 7.5dB. © 2012 OSA.

Adsorption of arsenite and arsenate on amorphous iron hydroxide

Adsorption isotherms in solutions with ionic strengths of 0.01 at 25°C were measured over the arsenite and arsenate concentration range 10−7−10−3 M and the pH range 4–10. At low concentrations, these isotherms obeyed equations of the Langmuir type. At higher concentrations the adsorption isotherms were linear, indicating the existence of more than one type of surface site on the amorphous iron hydroxide adsorbent. Removal of arsenite and arsenate by amorphous iron hydroxide throughout the concentration range were determined as a function of pH. By careful selection of the relative concentration of arsenic and amorphous iron hydroxide and pH, removals on the order of 92% can be achieved.