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Li Zhang

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Publications associées (40)

Distributed fiber temperature alarm system based on thermodynamic phase transition

Luc Thévenaz, Flavien Gyger, Li Zhang

A novel temperature sensing mechanism is proposed for the first time, based on thermodynamic phase transitions of CO2 in hollow-core fibers. A fast, sensitive and distributed fiber temperature alarm system is demonstrated using this concept. ...

Optica Publishing Group2020

Distributed and dynamic strain sensing with high spatial resolution and large measurable strain range

Luc Thévenaz, Zhisheng Yang, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

A distributed and dynamic strain sensing system based on frequency-scanning phase-sensitive optical time domain reflectometry is proposed and demonstrated. By utilizing an RF pulse scheme with a fast arbitrary waveform generator, a train of optical pulses ...

2020

Distributed optical fiber sensing based on frequency-scanned phase-sensitive optical time-domain reflectometry

Li Zhang

Unlike traditional sensing schemes which rely on discrete point sensors that perform measurements at predetermined positions, distributed optical fiber sensing is a general technique that enables to continuously gather information (typically temperature an ...

EPFL2020

Spectral Properties of the Signal in Phase-Sensitive Optical Time-Domain Reflectometry with Direct Detection

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu, Li Zhang

The spectral properties of the Rayleigh backscattered traces measured by a phase-sensitive optical time-domain reflectometer (øOTDR) with direct detection are theoretically and experimentally analyzed. The spectrum of the measured øOTDR signal is found to ...

IEEE Institute of Electrical and Electronics Engineers2020

Distributed hydrostatic pressure measurement using phase OTDR in a highly birefringent photonic crystal fiber

Luc Thévenaz, Li Zhang

Although distributed fiber-optic sensing of axial strain and temperature is a well-established technique, there are almost no demonstrations of distributed hydrostatic pressure sensing. The main obstacle for such measurements is the low sensitivity to pres ...

IEEE Institute of Electrical and Electronics Engineers2019

13.6% Efficient Organic Dye-Sensitized Solar Cells by Minimizing Energy Losses of the Excited State

Ulf Anders Hagfeldt, Li Zhang

The electron-injection energy losses of dye-sensitized solar cells (DSSCs) are among the fundamental problems hindering their successful breakthrough application. Two triazatruxene (TAT)-based sensitizers, with one containing a flexible Z-type double bond ...

AMER CHEMICAL SOC2019

Electron-Withdrawing Anchor Group of Sensitizer for Dye-Sensitized Solar Cells, Cyanoacrylic Acid, or Benzoic Acid?

Ulf Anders Hagfeldt, Li Zhang

High electron-injection efficiency is important for further development of dye-sensitized solar cells (DSSCs). Different electron acceptors have different electron-injection capabilities, which affect device performance. Herein, the effects of two organic ...

WILEY-V C H VERLAG GMBH2019

A kilometre-range distributed relative humidity sensor

Luc Thévenaz, Kenny Hey Tow, Li Zhang, Tiago Filipe Pimentel Das Neves

Fibre optics sensors have been identified as very good candidates for environmental monitoring inside the silicon detectors operated at CERN’s Large Hadron Collider. In this study, we present the results from the first highly sensitive relative humidity di ...

SPIE2019

Analysis and Reduction of Large Errors in Rayleigh-based Distributed Sensor

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Zhisheng Yang, Li Zhang, Luis Costa

Commonly, the frequency shift of back-reflection spectra is the key parameter to measure quantitatively local temperature or strain changes in frequency-scanned Rayleigh-based distributed fiber sensors. Cross-correlation is the most common method to estima ...

IEEE Institute of Electrical and Electronics Engineers2019

Distributed hydrostatic pressure measurement using phase-OTDR in a highly birefringent photonic crystal fibre

Luc Thévenaz, Kenny Hey Tow, Li Zhang

We demonstrate a distributed hydrostatic pressure measurement based on phase-sensitive optical time-domain reflectometry in a highly birefringent photonic crystal fibre with a 0.4 bar pressure resolution and a 10 cm spatial resolution. ...

Optical Society of America2018

Distributed hydrogen monitoring with phase-sensitive optical time-domain reflectometry

Luc Thévenaz, Li Zhang

We propose a distributed hydrogen sensing system based on ϕ-OTDR and a novel coating configuration with fiber adhesively bonding to palladium foils. An ultra-high sensitivedistributed hydrogen sensing with 5 cm spatial resolution is demonstrated ...

Optical Society of America2018

Fully distributed pressure sensing with ultra-high-sensitivity using side-hole fibers

Luc Thévenaz, Zhisheng Yang, Li Zhang

A highly sensitive distributed pressure sensing system (< 20 hPa) based on phasesensitive optical time-domain reflectometry with side air holes fiber is proposed, reaching a sensing range of 1.05 km with a 5 cm spatial resolution ...

Optical Society of America2018

Rayleigh-Based Distributed Optical Fiber Sensing Using Least Mean Square Similarity

Luc Thévenaz, Flavien Gyger, Zhisheng Yang, Li Zhang

Large frequency shift errors induced by cross-correlation are investigated in Rayleigh-based distributed sensing. A least mean square method is proposed to reduce those errors, thus increasing the reliability and extending the measurand range. ...

Optical Society of America2018

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

Nicolas Dupont, Françoise Gisou van der Goot Grunberg, Li Jin, Lionel Blanc, Andreas Kern, Andreas Mayer, Yin Chen, Darren Moore, Maurizio Molinari, Xu Liu, Jun Ren, Ziwei Qu, Li Yu, Xin Qi, Paolo Paganetti, Wei Chen, Peiwen Chen, Jian Zhang, Hong Jiang, Bo Wang, Yi Sun, Rakesh Kumar, Qi Chen, Si Chen, Ke Liu, Feng Xu, Qing Zhong, Hua Bai, Yang Sun, Sheng Li, Wei Liu, Peng Wang, Zhen Yan, Bo Liu, Fan Zhang, Jian Wu, Jian Wang, Li Zhang, Chih-Peng Chang, Giuseppe Russo, Sandra Moreno, Ying Jiang, Hong Zhang, Liang Xu, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Time and frequency pump-probe multiplexing to enhance the signal response of Brillouin optical time-domain analyzers

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Li Zhang

A technique to enhance the response and performance of Brillouin distributed fiber sensors is proposed and experimentally validated. The method consists in creating a multi-frequency pump pulse interacting with a matching multi-frequency continuous-wave pr ...

Optical Society of America2014

Enhanced response in Brillouin distributed optical fibre sensors by simultaneous time and frequency pump multiplexing

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Li Zhang

A technique to enhance the response of Brillouin distributed sensors is proposed and experimentally validated. The method consists in creating a multi-frequency pump pulse interacting with a multi-frequency continuous-wave probe. The power of each pulse at ...

SPIE2014

Minimizing distortion and enlarging group delay in Brillouin slow light systems by gain profile optimization

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Li Zhang

Optimal gain spectra minimizing distortion and enhancing delaying efficiency in linear slow light systems are predicted and experimentally validated by shaping the gain spectral profile in a Brillouin fiber amplifier. ...

Optical Society of America2014

Direct Observation of Two Electron Holes in a Hematite Photoanode during Photoelectrochemical Water Splitting

Michael Graetzel, Kevin Sivula, Artur Braun, Li Zhang, Jin Guo

Visible light active photoelectrodes for hydrogen generation by solar photoelectrochemical water splitting have been under scrutiny for many decades. In particular, the role of electron holes and charge transfer remains controversial. We have investigated ...

American Chemical Society2012

Iron Resonant Photoemission Spectroscopy on Anodized Hematite Points to Electron Hole Doping during Anodization

Michael Graetzel, Philippe Wyss, Kevin Sivula, Qianli Chen, Artur Braun, Li Zhang, Jin Guo

Anodization of a-Fe2O3 (hematite) electrodes in alkaline electrolyte under constant potential conditions the electrode surface in a way that an additional current wave occurs in the cyclic voltammogram. The energy position of this current wave is closely b ...

Wiley-Blackwell2012

The MicroArray Quality Control (MAQC)-II study of common practices for the development and validation of microarray-based predictive models

Vlad Popovici, Jun Luo, Darlene Goldstein, Mauro Delorenzi, Lu Meng, Li Li, Li Zhang, Wen Luo, Li Guo, Jonathan Koh Boon Han, Wei Wang, Rui Jiang, Jie Liu, Ying Liu, Chenxu Zhao, Rong Chen

Gene expression data from microarrays are being applied to predict preclinical and clinical endpoints, but the reliability of these predictions has not been established. In the MAQC-II project, 36 independent teams analyzed six microarray data sets to gene ...

Nature Publishing Group2010

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