11,968 research outputs found
Wavelength tunable 10-GHz 3-ps pulse source using a dispersion decreasing fiber-based nonlinear optical loop mirror
Full text linkWe experimentally demonstrate the use of a dispersion decreasing fiber (DDF)-based nonlinear optical loop mirror (NOLM) for the generation of wavelength tunable soliton-like pulses at a repetition rate of 10 GHz. We compress ~12 ps Gaussian pulses from an electro-absorption modulator (EAM) (followed by 125 m of DCF for preliminary linear dispersion compensation) into 3 ps pedestal-free pulses using both high-order soliton compression and nonlinear switching effects within an 8.5 km DDF-based loop mirror. The output pulses from the DDF-based NOLM show considerable pedestal reduction compared to those obtained by directly compressing the EAM seed pulses via a single passage through the DDF. Wavelength tuning of the compressed pulses over a ~15 nm bandwidth (from 1541 to 1556 nm) is demonstrated without a significant increase in pulse duration or degradation in pulse quality
New PS internal dump produced in the framework of the LHC Injector Upgrade (LIU) project
No full textNew PS internal dump produced in the framework of the LIU project : development of the internal shock absorber of the PS dump. This object will dynamically dampen the beam by a catapult movement performed in 300 ms
Effect of insulating-nanoparticles addition on ion current and voltage-holding ratio in nematic liquid crystal cells
No full textThe thermal decomposition of diazirines: 3-(3-methyldiazirin-3-yl)propan-1-ol and 3-(3-methyldiazirin-3-yl)propanoic acid
No full textPT: J; CR: BIGOT B, 1978, J AM CHEM SOC, V100, P6575 BRIDGE MR, 1969, J CHEM SOC A, P91 CHURCH RFR, 1970, J ORG CHEM, V35, P2465 CLOSS GL, 1965, J AM CHEM SOC, V87, P4270 EFFIO A, 1980, J AM CHEM SOC, V102, P1734 FIGUERA JM, 1976, AN QUIM, V72, P737 FIGUERA JM, 1978, J CHEM SOC F1, V74, P809 FIGUERA JM, 1979, J PHOTOCHEM, V10, P473 FREY HM, 1963, J CHEM SOC, P3514 FREY HM, 1964, J CHEM SOC, P4700 FREY HM, 1965, J CHEM SOC, P1700 FREY HM, 1965, J CHEM SOC, P3101 FREY HM, 1966, J CHEM SOC A, P968 FREY HM, 1977, J CHEM SOC F1, V73, P2010 FREY HM, 1979, J CHEM SOC A, P1916 GANZER GA, 1986, J AM CHEM SOC, V108, P1517 GRILLER D, 1982, J AM CHEM SOC, V104, P5549 LAL D, 1974, J AM CHEM SOC, V96, P6355 LIU MTH, 1972, INT J CHEM KINET, V4, P229 LIU MTH, 1972, J PHYS CHEM-US, V76, P797 LIU MTH, 1973, CAN J CHEM, V51, P2393 LIU MTH, 1974, J CHEM SOC P2, P937 LIU MTH, 1977, CAN J CHEM, V55, P3596 LIU MTH, 1982, CHEM SOC REV, V11, P127 LIU MTH, 1984, J CHEM SOC CHEM COMM, P1062 LIU MTH, 1984, TETRAHEDRON, V40, P887 LIU MTH, 1985, J CHEM SOC CHEM COMM, P982 LIU MTH, 1986, J CHEM SOC PERK T 2, P211 LIU MTH, 1987, CHEM DIAZIRINES, V1, P111 MANSOOR AM, 1966, TETRAHEDRON LETT, P1753 MANSOOR M, 1967, THESIS U SOUTHAMPTON MOSS RA, 1984, TETRAHEDRON LETT, V25, P1023 NEUVARAND EW, 1967, J PHYS CHEM-US, V71, P1229 SCHMID P, 1979, INT J CHEM KINET, V11, P333 SHERIDAN RS, 1984, J AM CHEM SOC, V106, P436 SKELL PS, 1972, TETRAHEDRON, V28, P3571 SMITH NP, 1979, J CHEM SOC P2, P213 SMITH RAG, 1975, J CHEM SOC P2, P686 VOIGT E, 1975, CHEM BER, V108, P3326; NR: 39; TC: 8; J9: J CHEM SOC PERKIN TRANS 2; PG: 7; GA: DD960Source type: Electronic(1
Analysis of PS-converted wave seismic data in the presence of azimuthal anisotropy
Full text linkShear-wave splitting and azimuthal variations of seismic attributes are two major
anisotropic effects induced by vertically-aligned fractures. They both have influences
on seismic data processing and interpretation, and provide information on fracture
properties. Azimuthal variations in P-wave data have been intensively studied to
improve imaging and obtain fracture parameters. However, azimuthal variations in
PS-converted wave seismic data, particularly the velocity variation in PS-converted
wave data, have not been well studied. Shear-wave splitting has been frequently used
to estimate fracture directions and densities. However, its influence on the azimuthal
variations of PS-converted wave data has also lacked a proper analysis. In this thesis,
I analyse the anisotropic behaviour of PS-converted wave seismic data in the
presence of azimuthal anisotropy, which includes the azimuthal variation of the PSconverted
wave and PS-converted wave splitting.
First, I demonstrate the robustness of PS-converted wave splitting for fracture
characterisation. PS-converted wave seismic data is also influenced by the splitting
effect due to its upgoing shear-wave leg. This important feature enables the
application of shear-wave splitting analysis to PS-converted wave seismic data. I use
synthetic data to show the necessity for separation of the split PS-converted waves.
Then I apply the PS-converted wave splitting analysis to Sanhu 3D3C land seismic
data. By separation of the fast and slow PS-converted waves and compensation for
the time delays, the imaging quality has been improved. Dominant fracture properties
obtained from the splitting analysis show a good correlation with the stress-field data.
However, this work is accomplished by assuming only one set of vertical fractures in
processing a given time window. In future work a specific layer-stripping algorithm
could be constructed and applied. .
Second, I study azimuthal variations of velocities in PS-converted wave seismic data.
It involves two major parts: analysing azimuthal variations of NMO velocities to
improve imaging, and examining the sensitivity of azimuthal variations to different
fluid saturations. For a layer with HTI anisotropy induced by a set of vertical
fractures, seismologists usually analyse the azimuthal behaviour exhibited on the
radial and transverse components, on which PS-converted wave data are recorded.
However, PS-converted waves also undergo shear-wave splitting, which complicates
the azimuthal variations of PS-converted wave data. I demonstrate that it is essential
to separate the fast P-SV1 wave from the slow P-SV2 wave, before applying any
azimuthal analysis. I derive an equation describing the azimuthal variation in PSconverted
wave NMO velocities, which shows the variation can be approximated
into an ellipse. Based on this theory, I build a workflow to analyse the azimuthal
variations of velocities in PS-converted wave data and apply this workflow to
synthetic data. The imaging quality can be improved by using this workflow.
Different fluid saturations in fractures have different influences on the azimuthal
variations of both P-wave and PS-converted wave data. I perform a numerical study
to understand how dry or water-saturated fractures control the azimuthal variations.
Through theoretical and synthetic studies, I find that the azimuthal variation of
velocities in PS-converted wave data is sensitive to different fluid saturations. By
analysing the azimuthal variation, the fracture properties can also be estimated, but
results are not as robust as those from PS-converted wave splitting analysis. I find
that azimuthal variations of fast P-SV1 and slow P-SV2 waves show in-phase
characteristics in dry fractures, but exhibit out-of-phase characteristics in water-saturated
fractures. This important feature could open a new application for using
PS-converted wave seismic data to distinguish oil-filled fractures from gas-filled
fractures. In cases where multiple HTI layers are involved, I have developed a
specific layer-stripping method to analyse both azimuthal variations and splitting
effects of PS-converted waves. By applying this method to synthetic data, the
fracture properties of each HTI layer can be estimated.
The analysis of azimuthal variations in PS-converted wave velocities is applied to
Daqing 3D3C land data. By using azimuthal velocity models in the PS-converted
wave seismic data processing, the imaging quality is improved, especially in the
anticline area where intensive fractures are likely to be developed. Furthermore, all
fracture information obtained from analysis of azimuthal variations and splitting
effects is compared with the stress-field data. The results from splitting analysis
show a better correlation with the stress-field study.
Finally, it is important to conclude that the analysis of PS-converted wave splitting is
a robust method to estimate fracture directions and densities. However, it is not
sensitive to different fluid saturations, which limits its application to fractured
reservoir characterisation. Azimuthal variations of PS-converted wave seismic data
can be analysed to improve imaging quality. Moreover their sensitivity to fluid
saturations may provide a new way to discriminate between oil-filled and gas-filled
fractures. However, the analysis of azimuthal variations is not as robust as the
analysis of splitting effects, and it may require appropriate calibration with other
fracture characterisation methods
Reactive intermediates in the photolysis and thermolysis of 3-chloro-3-benzyldiazirine
No full textPT: J; CR: BRADLEY GF, 1977, J CHEM SOC P2, P1214 DOLBY LJ, 1966, J ORG CHEM, V31, P110 ENGEL PS, 1980, CHEM REV, V80, P99 GRILLER D, 1983, J ORG CHEM, V48, P1359 HEGARTY AF, 1978, CHEM DIAZONIUM DIA 2, P511 JENNINGS BM, 1976, J AM CHEM SOC, V98, P6416 LIU MTH, 1974, J CHEM SOC P2, P937 LIU MTH, 1981, J CHEM SOC P2, P53 LIU MTH, 1982, CHEM SOC REV, V11, P127 MO YK, 1976, CARBONIUM IONS, V5, P2135 NAIDAN VM, 1972, ZH ORG KHIM, V8, P2172 SCHAEFER HF, 1979, ACC CHEM RES, V12, P88 SCHMITZ E, 1979, ADV HETEROCYCL CHEM, V24, P63 SMITH NP, 1979, J CHEM SOC P2, P213 SMITH RAG, 1975, J CHEM SOC P2, P686 TOMIOKA H, UNPUB TURRO NJ, 1980, J AM CHEM SOC, V102, P7576; NR: 17; TC: 12; J9: TETRAHEDRON; PG: 6; GA: SG656Source type: Electronic(1
All-optical signal processing using cascaded quadratic interactions in periodically poled lithium niobate waveguides
No full textThis thesis investigates all-optical signal processing using cascaded quadratic nonlinearities in periodically poled lithium niobate (PPLN) waveguides for telecommunication applications. PPLN waveguides which possess high second-order nonlinearity are attractive due to their suitable properties with respect to high compactness, high operating speed and resistance to parasitic effects. They allow the implementation of various advanced signal processing functionalities which will be required in future ultrahigh speed fibre-optic communication systems. Several novel all-optical signal processing techniques relying on two types of cascaded quadratic processes in PPLN waveguides, namely cascaded second harmonic generation and difference frequency generation (cSHG/DFG) and cascaded sum frequency generation and difference frequency generation (cSFG/DFG), are demonstrated. These two processes are conventionally employed for wavelength conversion in the telecommunication band. To facilitate the use of these wavelength converters, a systematic study of the acceptance bandwidths of cSHG/DFG and cSFG/DFG in PPLN waveguides is presented. Following this study, an optical time- divisionmultiplexing to wavelength-division multiplexing format conversion scheme, which relies on the generation of linearly chirped pulses which are then optically switched with data pulses using cSHG/DFG in a PPLN waveguide, is demonstrated. Signal regeneration techniques exploiting cascaded quadratic nonlinearities in PPLN waveguides are also investigated. An all-optical signal retiming system for on-off keying signals relying on pulse shaping and cSHG/DFG-based switching in a PPLN waveguide is demonstrated. Subsequently, two novel configurations of PPLN-based phase sensitive amplifiers (PSA) which have the potential as regenerators for phase-shift keying signals are demonstrated. Finally, a novel method for the elimination of arbitrary frequency chirp from short optical pulses is presented. In addition, the thesis contains a study on the use of OFCGs as telecommunication sub-picosecond pulse sources. Both a theoretical and experimental study of the intensity and phase properties of the pulses generated by an OFCG is presented. Furthermore, two approaches are proposed to compensate for the intrinsic chirp of the OFCGs
Injection septa position and angle optimisation in view of the 2 GeV liu upgrade of the CERN PS
No full textIn the framework of the LHC Injector Upgrade (LIU)project the CERN PS injection kinetic energy will be up-graded from 1.4 to 2 GeV. The injection equipment, whichis already operating close to its limit, is being redesigned tocope with 30% increase in the beam rigidity. In this paper wepresent the experimental results from Machine Development(MD) studies on the present septum to explore its operationalhardware limits with respect to aperture restrictions, beamlosses and kick strengths in view of the LIU upgrad
Butyl benzyl phthalate blocks Ca2+ signaling and catecholamine secretion coupled with nicotinic acetylcholine receptors in bovine adrenal chromaffin cells.
No full textElectrochemical behavior of diazirines
No full textPT: J; CR: ENGEL PS, 1980, CHEM REV, V80, P99 FRY AJ, 1973, J ORG CHEM, V38, P2620 KITAJEV JP, 1965, COLLECT CZECH CHEM C, V30, P4178 LIU MTH, 1981, J CHEM SOC P2, P53 LUND H, 1966, COLLECT CZECH CHEM C, V31, P4175 MALACHESKY PA, 1969, ANAL CHEM, V41, P1493 MOFFAT JB, 1978, CHEM DIAZONIUM DIA 1 NICHOLSON RS, 1964, ANAL CHEM, V36, P706 SCHWARZ WM, 1965, J PHYS CHEM-US, V69, P30; NR: 9; TC: 2; J9: J CHEM SOC CHEM COMMUN; PG: 2; GA: NJ399Source type: Electronic(1
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