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Matthew A Addicoat, Thomas D Bennett, Ivo Stassen
A lively discussion on new directions in porous crystalline materials took place in June 2017, with the beautiful city of Edinburgh as a backdrop, in the context of the unique Faraday Discussions format. Here, 5 minute presentations were given on papers which had been submitted in advance of the conference, with copious time allocated for in-depth discussion of the work presented. Prof. Mircea Dincă (MIT), chair of the scientific committee, opened the conference by welcoming the many different nationalities attending, and outlining the format of discussions...
September 21, 2017: Chemical Communications: Chem Comm
Auro M Perego
In this Letter, a fiber laser that exploits the dissipative Faraday instability as a pulse-generating mechanism is presented, and its dynamics are studied numerically. The proposed laser operates in the all-normal-dispersion regime and produces a train of quasi-parabolic pulses, with a repetition rate that can be controlled depending on the cavity dispersion and nonlinearity, ranging from 10 to 50 GHz. It exploits a lumped amplification scheme, which can be potentially realized with rare-earth gain media. The issues concerning the stability of the pulses are discussed, and the differences with similar pulsed lasers are highlighted...
September 15, 2017: Optics Letters
Anne-Isabelle Henry, Tyler W Ueltschi, Michael O McAnally, Richard P Van Duyne
Four decades on, surface-enhanced Raman spectroscopy (SERS) continues to be a vibrant field of research that is growing (approximately) exponentially in scope and applicability while pushing at the ultimate limits of sensitivity, spatial resolution, and time resolution. This introductory paper discusses some aspects related to all four of the themes for this Faraday Discussion. First, the wavelength-scanned SERS excitation spectroscopy (WS-SERES) of single nanosphere oligomers (viz., dimers, trimers, etc.), the distance dependence of SERS, the magnitude of the chemical enhancement mechanism, and the progress toward developing surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) are discussed...
September 14, 2017: Faraday Discussions
Xuyou Li, Pan Liu, Xingxing Guang, Zhenlong Xu, Lianwu Guan, Guangchun Li
Improving the performance of interferometric fiber optic gyroscope (IFOG) in harsh environments, such as magnetic field and temperature field variation, is necessary for its practical applications. This paper presents an investigation of Faraday effect-induced bias error of IFOG under varying temperature. Jones matrix method is utilized to formulize the temperature dependence of Faraday effect-induced bias error. Theoretical results show that the Faraday effect-induced bias error changes with the temperature in the non-skeleton polarization maintaining (PM) fiber coil...
September 7, 2017: Sensors
Mengfei Li, Christian Hansen, Georg Rose
PURPOSE: To assess the accuracy of medical electromagnetic tracking systems, reference positioning systems are generally required. Errors are unavoidable in such systems, and despite how tiny they may be, prevent the ground truth from being known. In this work, a simulator was developed and used to analyze the theoretical system performances in electromagnetic tracking. METHODS: To simulate the entire tracking process, the magnetic dipole model, Faraday's law, and a mathematical optimization algorithm are applied...
August 29, 2017: International Journal of Computer Assisted Radiology and Surgery
Pengyuan Chang, Huanfa Peng, Shengnan Zhang, Zhangyuan Chen, Bin Luo, Jingbiao Chen, Hong Guo
We present the design and performance characterization of a Faraday laser directly lasing on the Rb 1529 nm transition (Rb, 5P 3/2 - 4D 5/2) with high stability, narrow spectral linewidth and low cost. This system does not need an additional frequency-stabilized pump laser as a prerequisite to preparing Rb atom from 5S to 5P excited state. Just by using a performance-improved electrodeless discharge lamp-based excited-state Faraday anomalous dispersion optical filter (LESFADOF), we realized a heterogeneously Faraday laser with the frequency corresponding to atomic transition, working stably over a range of laser diode (LD) current from 85 mA to 171 mA and the LD temperature from 11 °C to 32 °C, as well as the 24-hour long-term frequency fluctuation range of no more than 600 MHz...
August 21, 2017: Scientific Reports
Zhaoqiang Chu, Huaduo Shi, Mohammad Javad PourhosseiniAsl, Jingen Wu, Weiliang Shi, Xiangyu Gao, Xiaoting Yuan, Shuxiang Dong
The magnetic flux gate sensors based on Faraday's Law of Induction are widely used for DC or extremely low frequency magnetic field detection. Recently, as the fast development of multiferroics and magnetoelectric (ME) composite materials, a new technology based on ME coupling effect is emerging for potential devices application. Here, we report a magnetoelectric flux gate sensor (MEFGS) for weak DC magnetic field detection for the first time, which works on a similar magnetic flux gate principle, but based on ME coupling effect...
August 17, 2017: Scientific Reports
Ningfang Song, Xiaoyang Wang, Xiaobin Xu, Wei Cai, Chunxiao Wu
We propose a method based on the white-light interference technique for measuring the Verdet constant of a polarization-maintaining air-core photonic bandgap fiber (PM-PBF). The experimental results show that the Verdet constant of the PM-PBF is ~3.3 mrad/T/m for the broadband light with a spectral width of ~38 nm and a mean wavelength of ~1550 nm, which is ~124 times less than that of a conventional stress-induced birefringent fibers called PANDA fibers (~0.41 rad/T/m for the same broad-spectrum light). The results indicate that the nonreciprocal error induced by the Faraday effect in a fiber optic gyroscope (FOG) made of the PM-PBF is theoretically ~25 times less than that of a conventional FOG made of the PANDA fiber when other conditions, such as the fiber twist, fiber coil area, and so on, are the same...
August 17, 2017: Sensors
Susumu Kitagawa
This paper is derived from my 'closing remarks' lecture at the 287th Faraday Discussions meeting on New Directions in Porous Crystalline Materials, Edinburgh, UK, 5-7 June, 2017. This meeting comprised sessions on the design of porous networks, and their capture, storage, separation, conducting properties, catalysts, resistance to chemicals and moisture, simulation, and electronic structures. This paper details the achievements and developments in the field, as reflected in invited speakers' papers and discussions with the attendees during the meeting...
September 1, 2017: Faraday Discussions
Michele Gianella, Tomas H P Pinto, Xia Wu, Grant A D Ritchie
We present the intra-cavity Faraday modulation spectroscopy technique, whereby optical feedback cavity-enhanced spectroscopy is coupled with Faraday modulation spectroscopy to greatly enhance the interaction path length of a laser beam with a paramagnetic sample in a magnetic field. We describe a first prototype based upon a cw quantum cascade laser targeting a selection of fundamental rovibrational R-branch transitions of nitric oxide (1890 cm(-1)), consisting of a linear cavity (finesse F=6300) and a water-cooled solenoid...
August 7, 2017: Journal of Chemical Physics
John Meurig Thomas
In 1861, Michael Faraday gave one of his last Friday Evening Discourses at the Royal Institution of Great Britain, London, on platinum, which he described as "this beautiful, magnificent and valuable metal". More than a hundred and twenty years later (in 1989), the author re-enacted, at the Royal Institution, many of the demonstrations that Faraday carried out in his memorable Discourse. This article outlines many of Faraday's views on, and experiments with, platinum. It also describes the continuing importance and utilization of platinum, both as perceived in 1989 and from present perspectives...
August 7, 2017: Chemical Communications: Chem Comm
Sir John Meurig Thomas
Biographers of Michael Faraday, as well as many dictionaries of science, often describe him as a physicist, which he certainly was. But he was also an astonishingly effective chemist: in fact, he was the Fullerian Professor of Chemistry (at the Royal Institution, RI) from 1834 until the time of his death in August, 1867. To mark the sesquicentenary of his passing, this editorial, by one of his distant successors as Director and Fullerian Professor at the RI, focuses on Faraday's output and influence as a scientist...
August 7, 2017: Chemical Communications: Chem Comm
Guiqin Wang, Tiantian Sun, Jifeng Xu
RATIONALE: According to the Johnson-Nyquist noise equation, the value of electron noise is proportional to the square root of the resistor value. This relationship gives a theoretical improvement of √100 in the signal/noise ratio by going from 10(11) Ω to 10(13) Ω amplifiers for Faraday detection in thermal ionization mass spectrometry (TIMS). METHODS: We measured Os isotopes using static Faraday cups with 10(13) Ω amplifiers in a negative thermal ionization mass spectrometry (NTIMS) and compared the results with those obtained with 10(11) Ω amplifiers and by peak hopping on a single secondary electron multiplier (SEM)...
July 27, 2017: Rapid Communications in Mass Spectrometry: RCM
Wei Deng, Hui Li, Chunxi Zhang, Pengjie Wang
The influence of optical parameters on the performance of closed-loop optical voltage sensors (OVSs) based on Pockels effect is analyzed and a control algorithm is proposed to suppress the nonlinearity caused by the unideal parameters of optical devices for optimizing the detection precision of OVSs. First, a quantified model of the feedback phase demonstrates how the optical parameters of optical devices (including light source, polarizer, 45° fusion point, Faraday rotator and half-wave plate) result in the nonlinearity of closed-loop OVSs...
July 27, 2017: Sensors
James A Dunne, David A Richards, Hsin-Wei Chen
Determination of (135)Cs/(137)Cs atom ratios has the potential to be a powerful tool for nuclear forensics and monitoring environmental processes. We present optimized chemical separation techniques and thermal ionization mass spectrometry (TIMS) protocols to obtain precise (135)Cs/(137)Cs atom ratios for a range of environmental sample types. We use a combination of double AMP-PAN separation and Sr-spec resin column purification to yield excellent separation from the alkali metals (Rb separation factor > 600), which normally suppress ionization of Cs...
November 1, 2017: Talanta
Cui Zhang, Prabesh Dulal, Bethanie J H Stadler, David C Hutchings
The first experimental TE-mode silicon-on-insulator (SOI) isolators using Faraday Rotation are here realized to fill the 'missing link' in source-integrated near infrared photonic circuits. The isolators are simple 1D 2-element waveguides, where garnet claddings and longitudinal magnetic fields produce nonreciprocal mode conversion, the waveguide equivalent of Faraday Rotation (FR). Quasi-phase matched claddings are used to overcome the limitations of birefringence. Current experimental SOI isolators use nonreciprocal phase shift (NRPS) in interferometers or ring resonators, but to date NRPS requires TM-modes, so the TE-modes normally produced by integrated lasers cannot be isolated without many ancillary polarisation controls...
July 19, 2017: Scientific Reports
D P Hewett, I J Hewitt
[This corrects the article DOI: 10.1098/rspa.2016.0062.].
June 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
A P Espejo, F Tejo, N Vidal-Silva, J Escrig
In this work we introduce an alternating magnetic field generator in a cylindrical nanostructure. This field appears due to the rotation of a magnetic domain wall located at some position, generating a magnetic region that varies its direction of magnetization alternately, thus inducing an alternating magnetic flux in its vicinity. This phenomenon occurs due to the competition between a spin-polarized current and a magnetic field, which allows to control both the angular velocity and the pinning position of the domain wall...
July 5, 2017: Scientific Reports
Mark W Rutland
It is an honour to be charged with providing the concluding remarks for a Faraday Discussion. As many have remarked before, it is nonetheless a prodigious task, and what follows is necessarily a personal, and probably perverse, view of a watershed event in the Chemical Physics of Electroactive materials. The spirit of the conference was captured in a single sentence during the meeting itself."It is the nexus between rheology, electrochemistry, colloid science and energy storage". The current scientific climate is increasingly dominated by a limited number of global challenges, and there is thus a tendency for research to resemble a football match played by 6 year olds, where everyone on the field chases the (funding) ball instead of playing to their "discipline"...
July 1, 2017: Faraday Discussions
Shaoyi Xu, Haiming Shao, Chuansheng Li, Fangfang Xing, Yuqiao Wang, Wei Li
In this work, a linear birefringence measurement method is proposed for an optical fiber current sensor (OFCS). First, the optical configuration of the measurement system is presented. Then, the elimination method of the effect of the azimuth angles between the sensing fiber and the two polarizers is demonstrated. Moreover, the relationship of the linear birefringence, the Faraday rotation angle and the final output is determined. On these bases, the multi-valued problem on the linear birefringence is simulated and its solution is illustrated when the linear birefringence is unknown...
July 3, 2017: Sensors
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