ISIS IR: The first infrared fibre-fed spectrograph

ISIS IR is the first attempt to use fibre optics for near infrared spectroscopy (1.8m). It is a field spectrograph (2D spectroscopy), and can work at various resolving powers (up to 25000). It can be transported anywhere, and soon it will be used at CFHT with one NICMOS 3-based camera.Département d'Astrophysique Extragalactique et de Cosmologie     

Field testing of modular borehole monitoring with simultaneous distributed acoustic sensing and geophone vertical seismic profiles at Citronelle,Alabama

A modular borehole monitoring concept has been implemented to provide a suite of well‐based monitoring tools that can be deployed cost effectively in a flexible and robust package. The initial modular borehole monitoring system was deployed as part of a CO₂ injection test operated by the Southeast Regional Carbon Sequestration Partnership near Citronelle, Alabama. The Citronelle modular monitoring system transmits electrical power and signals, fibre‐optic light pulses, and fluids between the surface and a reservoir. Additionally, a separate multi‐conductor tubing‐encapsulated line was used for borehole geophones, including a specialized clamp for casing clamping with tubing deployment. The deployment of geophones and fibre‐optic cables allowed comparison testing of distributed acoustic sensing. We designed a large source effort (>64 sweeps per source point) to test fibre‐optic vertical seismic profile and acquired data in 2013. The native measurement in the specific distributed acoustic sensing unit used (an iDAS from Silixa Ltd) is described as a localized strain rate. Following a processing flow of adaptive noise reduction and rebalancing the signal to dimensionless strain, improvement from repeated stacking of the source was observed. Conversion of the rebalanced strain signal to equivalent velocity units, via a scaling by local apparent velocity, allows quantitative comparison of distributed acoustic sensing and geophone data in units of velocity. We see a very good match of uncorrelated time series in both amplitude and phase, demonstrating that velocity‐converted distributed acoustic sensing data can be analyzed equivalent to vertical geophones. We show that distributed acoustic sensing data, when averaged over an interval comparable to typical geophone spacing, can obtain signal‐to‐noise ratios of 18 dB to 24 dB below clamped geophones, a result that is variable with noise spectral amplitude because the noise characteristics are not identical. With vertical seismic profile processing, we demonstrate the effectiveness of downgoing deconvolution from the large spatial sampling of distributed acoustic sensing data, along with improved upgoing reflection quality. We conclude that the extra source effort currently needed for tubing‐deployed distributed acoustic sensing vertical seismic profile, as part of a modular monitoring system, is well compensated by the extra spatial sampling and lower deployment cost as compared with conventional borehole geophones.     

碳纤维加固技术在水利工程中的应用研究

针对王铺渡槽上部墩柱结构出现的大开度贯穿性裂缝,课题组经过全面分析和多方案综合对比,采用裂缝化灌、碳纤维加固、外表面刷涂水性环保型乳胶漆外墙涂料作为防护的综合措施对原工程进行有效的加固处理,并结合水利工程的自身特点改进了加固技术工艺,取得了显著的经济和社会效益.     

加拿大海王星:科学、运行、管理

加拿大海王星是世界最大的海底缆接科学观测网,于2009年开始运行.它连接了位于不同水深和不同海洋地质环境的大批观测仪器,把数据连续不断地通过互联网传给科学家和大众.海王星的建立是为了推动地震过程和大地构造、海底地下流体、海洋生物与气候变化、深海生态系统、工程和信息科学等五大科学命题的研究.为最大程度地推动国际合作,加速科学发展步伐,它的系统使用完全开放,数据全部免费公开,这在科学史上前所未见.这种全方位、全开放的复杂庞大的科研系统需要高超的管理方法和优良的学术环境.     

Superhydrophobic and superoleophillic surface of porous beaded electrospun polystrene and polysytrene-zeolite fiber for crude oil-water separation

This research presents a cheap route procedure for the preparation of a potential adsorbent with superhydrophobic/superoleophillic properties for selective removal of crude oil from water. In this study, expanded polystyrene (EPS) was electrospun to produce beaded fibers in which zeolite was introduced to the polymer matrix in order to impart rough surface to non-beaded fiber. Films of the EPS and EPS/Zeolite solutions were also made for comparative study. The electrospun fibers EPS, EPS/Zeolite and resultant films were characterized using SEM, BET, FTIR and optical contact angle. The fibers exhibited superhydrophobic and superoleophillic wetting properties with water (>150⁰) and crude oil (0⁰). The selective removal of crude oil presents new opportunity for the re-use of EPS as adsorbent in petroleum/petrochemical industry.     

An avalanche photodiode photon counting camera for high-resolution astronomy

A system is described which makes best use of the high quantum efficiency and high count rate capability of avalanche photodiodes for high time resolution observations of optical pulsars. The use of three APDs allows simultaneous photometry of the target and a reference star, and the monitoring of the sky background. By minimising the optical components in the light path the optical efficiency of the system is maximised. The TRIFFID (Shearer, A., Stappers, B., O'Connor, P., Golden, A., Strom, R., Redfern, M., Ryan, O.: Science 301, 493–495 (2003)) and OPTIMA (Straubmeier, C., Kanbach, G., Schrey, F.: Exp. Astron. 11, 157–170 (2001)) have shown that fibre-fed APD arrays can produce excellent results. This, new, system was used on the 6m BTA in November 2003 – results on the Crab pulsar are presented.     

Superoleophillic electrospun polystrene/exofoliated graphite fibre for selective removal of crude oil from water

During oil spills, the aquatic environment is greatly endangered because oil floats on water making the penetration of sunlight difficult therefore primary productivity is compromised, birds and aquatic organisms are totally eliminated within a short period. It is therefore essential to remove the oil from the water bodies after the spillage. This work reports on the fabrication of oil loving electrospun polystyrene-exofoliated graphite fibre with hydrophobic and oleophillic surface properties. The fibre was applied for the selective adsorption of crude oil from simulated crude oil spillage on water. The maximum oil adsorption capacity of the EPS/EG was 1.15 kg/g in 20 min while the lowest oil adsorption capacity was 0.81 kg/g in 10 min. Cheap oil adsorbent was developed with superoleophillic and superhydrophobic properties.     

The effect of gauge length on axially incident P‐waves measured using fibre optic distributed vibration sensing

Distributed vibration sensing, also known as distributed acoustic sensing, is a relatively new method for recording vertical seismic profile data using a fibre optic cable as the sensor. The signal obtained from such systems is a distributed measurement over a length of fibre referred to as the gauge length. In this paper, we show that gauge length selection is one of the most important acquisition parameters for a distributed vibration sensing survey. If the gauge length is too small, then the signal‐to‐noise ratio will be poor. If the gauge length is too large, resolution will be reduced and the shape of the wavelet will be distorted. The optimum gauge length, as derived here, is a function of the velocity and frequencies of the seismic waves being measured. If these attributes vary considerably over the depth of a survey, then the use of different gauge lengths is recommended. The significant increases in data quality resulting from the use of multiple gauge length values are demonstrated using field data.     

加卸载响应比(LURR)响应量的研究

加卸载响应比(LuRR)理论以响应比值Y来刻画孕震区介质的损伤演化进程。在计算Y值时可选择能量(Benioff应变)、模量(应变)等多种物理量做响应。本通过理论和实验方法对使用不同响应量时Y值演化趋势的异同进行了研究，结果表明在Y达到峰值之前具有相似地演化过程。     

光纤陀螺的发展及其在惯导中的应用前景

介绍了光纤陀螺的基本原理,对其优缺点和主要误差源做了阐述.对光纤陀螺在惯性导航中的应用状况进行分析,介绍了发达国家及我国光纤陀螺技术的发展现状,并对光纤陀螺的发展前景做了展望.