158-μJ pulses from a single-transverse-mode, large-mode-area erbium-doped fiber amplifier

We report the amplification of 10-100-pJ semiconductor diode pulses to an energy of 158 μJ and peak powers >100 kW in a multistage fiber amplifier chain based on a single-mode, large-mode-area erbium-doped amplifier design. To our knowledge these results represent the highest single-mode pulse energy extracted from any doped-fiber system. © 1997 Optical Society of America.

Tutorial on loop shaping using H-infinity robust stabilization

A new method for multivariable control was proposed in McFarlane and Glover (1988 CDC). This method involved shaping the open-loop singular values with pre and/or post compensators and then designing a controller to robustly stabilize a normalized coprime factorization of this weighted plant. The method has many attractive features including guaranteed loop shape and robust stability and performance. This talk will outline the rationale of this method and illustrate its use on a number of applications.

Viscoelastic microbuckling of fiber composites

A theoretical study is given of viscoelastic microbuckling of fiber composites. The analysis is formulated in terms of general linear viscoelastic behavior within the kink band. Material outside the kink band is assumed to behave elastically. Two specific forms of linear viscoelastic behavior are considered: a standard linear viscoelastic model and a logarithmically creeping model. Results are provided as deformation versus time histories and failure life versus applied stress. Failure is due to either the attainment of a critical failure strain in the kink band or to the intervention of a different failure mechanism such as plastic microbuckling.

High bandwidth multimode fiber links using subcarrier multiplexing in vertical-cavity surface-emitting lasers

The usage of subcarrier multiplexing (SCM) techniques to allow link transmission in excess of the specified fiber bandwidth is described. A series of 200-Mbit/s channels with carrier frequencies of up to more than twenty times the 3-dB fiber bandwidth have been successfully used, the maximum being limited by the available electronics. To assess the transmission of the fiber, digitally modulated channels are placed on high frequency carrier signals and then used to modulate a vertical-cavity surface-emitting lasers (VCSEL).

10-Gbit/s transmission over 300-m standard multimode fiber using multilevel coding and 2-channel WDM

A combination of multilevel coding schemes and simple two-channel wavelength division multiplexing (WDM) at 1300 and 1550 nm was used to transmit an aggregate of 10 Gbit/s over 300 m of multimode fiber that is typical of that employed in current Local Area Networks (LANs). It was shown that this technique could be a simple solution for achieving 10 Gigabit ethernet links over installed multimode fiber building backbones.

Subcarrier modulation for transmission of 1-Gbit/s channels over 500 m of 62.5-μm multimode fiber

The use of two different subcarriers at frequencies up to 5.5 GHz each transmitting 1 Gbit/s over 500 m of multimode fiber (MMF) is demonstrated. By transmitting the two subcarrier channels simultaneously alongside the baseband signal, an aggregate bit rate of 2.8 Gbit/s is possible.

Distributed optical fiber strain sensing in a secant piled wall

An optical fiber strain sensing technique, based on Brillouin Optical Time Domain Reflectometry (BOTDR), was used to obtain the full deformation profile of a secant pile wall during construction of an adjacent basement in London. Details of the installation of sensors as well as data processing are described. By installing optical fiber down opposite sides of the pile, the distributed strain profiles obtained can be used to give both the axial and lateral movements along the pile. Measurements obtained from the BOTDR were found in good agreement with inclinometer data from the adjacent piles. The relative merits of the two different techniques are discussed. © 2007 ASCE.

Monitoring tunnel deformation induced by close-proximity bored tunneling using distributed optical fiber strain measurements

The paper describes the use of optical fiber Brillouin Optical Time Domain Reflectometry (BOTDR) to monitor the strain distribution in an existing tunnel while a twin tunnel was bored at close-proximity. The twin circular bored tunnels between Serangoon and Bartley stations on the new Circle Line Stage 3 subway in Singapore were constructed at close-proximity to avoid underpinning the foundations of adjacent buildings. The minimum clear separation of the two tunnels is 2.3m (0.4 times the tunnel diameter). The Outer Tunnel was constructed first, followed by the Inner Tunnel, with the earth-pressure balance tunnel boring machines maintained at a minimum of 100m apart. In this trial application of BOTDR, the strain distribution along the Outer Tunnel was measured, in order to monitor its deformation due to the boring of the Inner Tunnel at close-proximity. The aim of the trial application was to determine the practicality of this monitoring method for future use in 'live' tunnels. This paper compares the measurements obtained from optical fiber BOTDR with conventional methods of tunnel monitoring and describes preliminary installation and workmanship guidelines derived from lessons learnt during this trial. © 2007 ASCE.

Trypsin inhibitory loop is an excellent lead structure to design serine protease inhibitors and antimicrobial peptides

The disulfide-bridged hendecapeptide ( CWTKSIPPKPC) loop, derived from an amphibian skin peptide, is found to have strong trypsin inhibitory capability. This loop, called the trypsin inhibitory loop ( TIL), appears to be the smallest serine protease inhib

Model-based thermoacoustic oscillation control via ℋ ∞ loop-shaping and integral quadratic constraints

Lean premixed prevaporized (LPP) technology has been widely used in the new generation of gas turbines in which reduced emissions are a priority. However, such combustion systems are susceptible to the damage of self-excited oscillations. Feedback control provide a way of preventing such dynamic stabilities. A flame dynamics assumption is proposed for a recently developed unsteady heat release model, the robust design technique, ℋ ∞ loop-shaping, is applied for the controller design and the performance of the controller is confirmed by simulations of the closed-loop system. The Integral Quadratic Constraints(IQC) method is employed to prove the stability of the closed-loop system. ©2010 IEEE.

云南保山猪线粒体DNA D loop区序列初步分析

为了解云南保山猪(Baoshan pig)的遗传多样性及其遗传背景，我们测定了19个个体线粒体DNA Dloop高变区1 1 5 363 - 1 5 801片段序列438帅。检测到1。种单倍型，包括8个多态位点，其中5次T/ C转换、1次G/ A转换、1次G/ C颠换和1次A/ T颠换，其A.T.GX碱基的平均含量分别为35.4%.26.9%.13.2%和24.5 %,A+ T含量(62 .3)明显高于G+ C含量(37 .7 %)。对于保山猪的保种及其持续利用有着重要的理论指导意义。