The increased adoption of non-invasive laser-based techniques for analysis of cultural assets has... more The increased adoption of non-invasive laser-based techniques for analysis of cultural assets has recently called into question the non-invasiveness of the techniques in practical operation. The methods to assess the occurrence of radiation-induced alteration on paintings are very limited and none of them can predict damage. Here we present a novel multimodal imaging approach to understand the time and spatial evolution and types of laser-induced surface alterations, through simultaneous monitoring using visible and near infrared (VIS-NIR) reflectance hyperspectral imaging (HSI) and thermal imaging during Raman spectroscopy. The resultant physical and chemical changes were examined in detail by optical coherence tomography and synchrotron based micro-X-ray powder diffraction. HSI was found to be the most sensitive in detecting laser induced alternations compared with conventional methods. It is orders of magnitude more sensitive than Raman spectroscopy and even synchrotron-based micro-X-ray powder diffraction. In cases of thermally driven alterations, transient and reversible reflectance changes were found to be the first indications of laser-induced modifications and can therefore be used as precursors to prevent damage. VIS-NIR reflectance spectroscopy should be used to monitor laser-based analysis and potentially other radiation-based techniques in situ to mitigate laser induced alteration. † Electronic supplementary information (ESI) available: Fig. S1 to S9.
Publications of the Astronomical Society of Australia, Oct 1, 1996
We present observations of the Sunyaev-Zel'dovich effect in 5 clusters of galaxies with a Fou... more We present observations of the Sunyaev-Zel'dovich effect in 5 clusters of galaxies with a Fourier synthesis telescope - the Australia Telescope. A synthesis telescope has the advantage of simultaneously imaging the discrete radio sources and the Sunyaev-Zel'dovich effect. Observations were made at 8.8 GHz and in an ultra-compact 122.4m array configuration. Extended emission either due to radio halo sources or a blend of weak radio sources below the detection threshold, limited our ability to detect the SZ effect. However, upper limits to the SZ effect obtained for the cluster MS2137-23 was useful in constraining the cluster gas temperature when combined with the X-ray measurements and gravitational lensing constraints. The advantages of a multi-wavelength analysis of cluster mass density distributions and the properties of the intra-cluster medium were demonstrated through the examples of MS2137-23 and Abell 2218. Both clusters possess a giant arc that constrains the cluster central mass. In the case of Abell 2218 where there is a large amount of good data available in various wave-bands, we combined gravitational lensing constraints, optical photometry, measurements of the Sunyaev-Zel'dovich effect, X-ray surface brightness and temperature to constrain the cluster potential. H₀ and test the usual assumptions of mass-follows- light and hydrostatic equilibrium.
The new SIRIS (Scanning InfraRed Imaging System) camera developed at the National Gallery in Lond... more The new SIRIS (Scanning InfraRed Imaging System) camera developed at the National Gallery in London allows highresolution images of paintings to be made in the near infrared region (900-1700 nm). Images of 5000 × 5000 pixels are made by moving a 320 × 256 pixel InGaAs array across the focal plane of the camera using two orthogonal translation stages. The great advantages of this camera over scanning infrared devices are its relative portability and that image acquisition is comparatively rapid-a full 5000 × 5000 pixel image can be made in around 20 minutes. The paper describes the development of the mechanical, optical and electronic components of the camera, including the design of a new lens. The software routines used to control image capture and to assemble the individual 320 × 256 pixel frames into a seamless mosaic image are also mentioned. The optics of the SIRIS camera have been designed so that the camera can operate at a range of resolutions; from around 2.5 pixels per millimetre on large paintings of up to 2000 × 2000 mm to 10 pixels per millimetre on smaller paintings or details of paintings measuring 500 × 500 mm. The camera is primarily designed to examine underdrawings in paintings; preliminary results from test targets and paintings are presented and the quality of the images compared with those from other cameras currently used in this field.
ABSTRACT A Fourier domain (FD) optical coherence tomography (OCT) system is shown to be capable o... more ABSTRACT A Fourier domain (FD) optical coherence tomography (OCT) system is shown to be capable of profilometry with two orders of magnitude better accuracy than the axial imaging resolution of the system. High precision OCT profilometry not only achieves similar accuracy as commercial white light interferometry based profilometers but is also capable of profilometry on complex subsurface structures with multiple interfaces of low reflectance. An accuracy of 55nm was achieved with a ThorLabs SROCT on a lab bench without special anti-vibration devices. This technique has the potential for a range of applications, such as high precision refractive index measurements and simultaneous dynamic monitoring of the interface structure of a drying varnish and the substrate.
While OCT has been applied to the non-invasive examination of the stratigraphy of paint layers in... more While OCT has been applied to the non-invasive examination of the stratigraphy of paint layers in recent years, it has been recognized that the resolutions of commercially available OCT cannot compete in depth resolution with conventional microscopic examination of cross-sections of paint samples. It is necessary to achieve resolutions better than 3 microns to resolve the thinnest layers of paint and varnish. In this paper, we demonstrate a Fourier domain ultrahigh resolution OCT at 810nm with depth resolution of 1.8 u.m in air (or 1.2u.m in varnish or paint).
Optical Coherence Tomography has been successfully applied to the imaging of painted objects in r... more Optical Coherence Tomography has been successfully applied to the imaging of painted objects in recent years. However, a significant limitation is the low penetration depth of OCT in paint because of the high opacity of paint due to either scattering or absorption. It has been shown that the optimum spectral window for OCT imaging of paint layers is around 2.2u.m in wavelength. In this paper, we demonstrate a 1950nm OCT for imaging painted objects using a superfluorescent fiber source at low power.
We present a prototype portable remote multispectral imaging system, PRISMS (Portable Remote Imag... more We present a prototype portable remote multispectral imaging system, PRISMS (Portable Remote Imaging System for Multispectral Scanning), that is lightweight , flexible and without any cumbersome mechanical structure for in situ high resolution colour and spectral imaging of large and inaccessible paintings such as wall paintings. This is the first instrument to be able to image paintings at inaccessible heights in situ from ground level to produce not only high resolution colour images but also multispectral images.
Monthly Notices of the Royal Astronomical Society, Sep 1, 2002
We study the origin of the non-thermal emission from the intracluster medium, including the exces... more We study the origin of the non-thermal emission from the intracluster medium, including the excess hard X-ray emission and cluster-wide radio haloes, through fitting two representative models to the Coma cluster. If the synchrotron-emitting relativistic electrons are accelerated in situ from the vast pool of thermal electrons, then a quasi-stationary solution of the kinetic equation with particle acceleration through turbulence at high energies (>200 keV) naturally produces a population of suprathermal electrons responsible for the excess hard X-ray emission through bremsstrahlung. Inverse Compton scattering is negligible at hard X-ray energies in this case. The radio halo flux density constrains the magnetic field strength to a value close to that of equipartition, ∼1 µG. Alternatively, if the relativistic electrons are injected from numerous localized 'external' sources, then the hard X-rays are best explained by inverse Compton scattering from GeV electrons, and little of the hard X-radiation has a bremsstrahlung origin. In this case, the magnetic field strength is constrained to ∼0.1-0.2 µG. Both models assume that the non-thermal emissions are generated by a single electron spectrum, so that only two free parameters, well constrained by the observed hard X-ray and radio halo spectra, are needed in either case. Measurements of the cluster magnetic field will distinguish between the models.
An optical coherence tomography (OCT) system using a compact fiber source emitting amplified spon... more An optical coherence tomography (OCT) system using a compact fiber source emitting amplified spontaneous emission (ASE) at central wavelength of 1960nm with bandwidth of 40nm is developed to enhance the probing depth in highly scattering material with low water content. Examples of application to paint is used to demonstrate significantly improved penetration depth in high opacity material in the two-micron wavelength regime.
Using non-invasive non-destructive techniques to monitor cultural heritage objects Cultural herit... more Using non-invasive non-destructive techniques to monitor cultural heritage objects Cultural heritage plays a significant role in our identities and well-being. The aim of conservation is to manage change to cultural heritage objects. Non-destructive techniques offer an opportunity to quantify deterioration objectively and at an earlier stage than observation. There are limitations for using the techniques on precious artefacts. This paper examines some of the issues and opportunities through case studies with phased pulse thermography, acoustic emission, Fourier transform infrared spectroscopy and optical coherence tomography, applied to a series of mediaeval Limoges enamel plaques from the Werner Collection, displayed at Rangers House, London.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
As part of a 4-year Cosmology and Particle Astrophysics (CosPA) Research Excellence Initiative in... more As part of a 4-year Cosmology and Particle Astrophysics (CosPA) Research Excellence Initiative in Taiwan, AMiBA − a 19-element dual-channel 85-105 GHz interferometer array is being specifically built to search for high redshift clusters of galaxies via the Sunyaev-Zeldovich Effect (SZE). In addition, AMiBA will have full polarization capabilities, in order to probe the polarization properties of the Cosmic Microwave Background. AMiBA, to be sited on Mauna Kea in Hawaii or in Chile, will reach a sensitivity of ∼ 1 mJy or 7µK in 1 hour. The project involves extensive international scientific and technical collaborations. The construction of AMiBA is scheduled to starting operating in early 2004.
We will discuss the properties and origins of halos and relics including estimates of the cluster... more We will discuss the properties and origins of halos and relics including estimates of the cluster magnetic fields, and present results for a few recently discovered halos and relics. The electrons in the suprathermal high energy tail of the thermal gas distribution are likely to provide the seed particles for acceleration through mergers and turbulences to relativistic energies. These relativistic particles are then responsible for the synchrotron emission of the halos.
The design and experimental method for the use of a novel instrument for lightfastness measuremen... more The design and experimental method for the use of a novel instrument for lightfastness measurements on artwork is presented. The new microfadometer design offers increased durability and portability over the previous, published design, broadening the scope of locations at which data can be acquired. This reduces the need for art handling or transportation in order to gain evidence-based risk assessments for the display of light-sensitive artworks. The instrument focuses a stabilized high powered xenon lamp to a spot 0.25 millimeters (FWHM) while simultaneously monitoring color change. This makes it possible to identify pigments and determine the lightfastness of materials effectively and non-destructively. With 2.59mW or 0.82 lumens (1.7 x10 7 lux for a 0.25mm focused spot) the instrument is capable of fading Blue Wool 1 to a measured 11 ∆E ab value (using CIE standard illuminant D65) in 15 minutes. The temperature increase created by focused radiation was measured to be 3 to 4°C above room temperature. The system was stable within 0.12 ∆E ab over 1 hour and 0.31 ∆E ab over 7 hours. A safety evaluation of the technique is discussed which concludes that some caution should be employed when fading smooth, uniform areas of artworks. The instrument can also incorporate a linear variable filter. This enables the researcher to identify the active wavebands that cause certain degradation reactions and determine the degree of wavelength dependence of fading. Some preliminary results of fading experiments on Prussian blue samples from the paint box of J. M. W Turner (1755-1851) are presented.
PRISMS (Portable Remote Imaging System for Multispectral Scanning) is a multispectral/hyperspectr... more PRISMS (Portable Remote Imaging System for Multispectral Scanning) is a multispectral/hyperspectral imaging system designed for flexible in situ imaging of wall paintings at high resolution (tens of microns) over a large range of distances (less than a meter to over ten meters). This paper demonstrates a trial run of the VIS/NIR (400-880nm) component of the instrument for non-invasive imaging of wall paintings in situ. Wall painting panels from excavated Tang dynasty (618-907AD) tombs near Xi'an were examined by PRISMS. Pigment identifications were carried out using the spectral reflectance obtained from multispectral imaging coupled with non-invasive elemental analysis using a portable XRF.
Journal of Colloid and Interface Science, Apr 1, 2013
In this work, we present the visualization of the internal flows in a drying sessile polymer disp... more In this work, we present the visualization of the internal flows in a drying sessile polymer dispersion drop on hydrophilic and hydrophobic surfaces with Spectral Radar Optical Coherence Tomography (SR-OCT). We have found that surface features such as the initial contact angle and pinning of the contact line, play a crucial role on the flow direction and final shape of the dried drop. Moreover, imaging through selection of vertical slices using optical coherence tomography offers a feasible alternative compared to imaging through selection of narrow horizontal slices using confocal microscopy for turbid, barely transparent fluids.
We correct a mistake in the OCT system sensitivity given in our recent paper [Opt. Express23(3), ... more We correct a mistake in the OCT system sensitivity given in our recent paper [Opt. Express23(3), 1992 (2015) 10.1364/OE.23.00199225836070].
The Array for Microwave Background Anisotropy (AMiBA) is an interferometric array of 19 dishes co... more The Array for Microwave Background Anisotropy (AMiBA) is an interferometric array of 19 dishes co-mounted on a steerable platform and operating at 95 GHz. One of the main scientific aims of AMiBA is to conduct cluster surveys using the Sunyaev-Zel'dovich (SZ) effect. Here we explore the potential of AMiBA as a tailor-made SZ instrument for the study of cluster physics and cosmology via cluster surveys out to the epoch of cluster formation. In particular, we explore the potential of combining AMiBA cluster surveys with the XMM-LSS (Large Scale Structure) survey.
This paper will introduce a new application of Optical Coherence Tomography (OCT) to the monitori... more This paper will introduce a new application of Optical Coherence Tomography (OCT) to the monitoring of vulnerability of rock art monuments in-situ. The porosity of the host rock is an important factor affecting the susceptibility of rock art monuments to decay. Pore characteristics of rocks are one of the main factors that control the intensity of physical deterioration. OCT has
The increased adoption of non-invasive laser-based techniques for analysis of cultural assets has... more The increased adoption of non-invasive laser-based techniques for analysis of cultural assets has recently called into question the non-invasiveness of the techniques in practical operation. The methods to assess the occurrence of radiation-induced alteration on paintings are very limited and none of them can predict damage. Here we present a novel multimodal imaging approach to understand the time and spatial evolution and types of laser-induced surface alterations, through simultaneous monitoring using visible and near infrared (VIS-NIR) reflectance hyperspectral imaging (HSI) and thermal imaging during Raman spectroscopy. The resultant physical and chemical changes were examined in detail by optical coherence tomography and synchrotron based micro-X-ray powder diffraction. HSI was found to be the most sensitive in detecting laser induced alternations compared with conventional methods. It is orders of magnitude more sensitive than Raman spectroscopy and even synchrotron-based micro-X-ray powder diffraction. In cases of thermally driven alterations, transient and reversible reflectance changes were found to be the first indications of laser-induced modifications and can therefore be used as precursors to prevent damage. VIS-NIR reflectance spectroscopy should be used to monitor laser-based analysis and potentially other radiation-based techniques in situ to mitigate laser induced alteration. † Electronic supplementary information (ESI) available: Fig. S1 to S9.
Publications of the Astronomical Society of Australia, Oct 1, 1996
We present observations of the Sunyaev-Zel'dovich effect in 5 clusters of galaxies with a Fou... more We present observations of the Sunyaev-Zel'dovich effect in 5 clusters of galaxies with a Fourier synthesis telescope - the Australia Telescope. A synthesis telescope has the advantage of simultaneously imaging the discrete radio sources and the Sunyaev-Zel'dovich effect. Observations were made at 8.8 GHz and in an ultra-compact 122.4m array configuration. Extended emission either due to radio halo sources or a blend of weak radio sources below the detection threshold, limited our ability to detect the SZ effect. However, upper limits to the SZ effect obtained for the cluster MS2137-23 was useful in constraining the cluster gas temperature when combined with the X-ray measurements and gravitational lensing constraints. The advantages of a multi-wavelength analysis of cluster mass density distributions and the properties of the intra-cluster medium were demonstrated through the examples of MS2137-23 and Abell 2218. Both clusters possess a giant arc that constrains the cluster central mass. In the case of Abell 2218 where there is a large amount of good data available in various wave-bands, we combined gravitational lensing constraints, optical photometry, measurements of the Sunyaev-Zel'dovich effect, X-ray surface brightness and temperature to constrain the cluster potential. H₀ and test the usual assumptions of mass-follows- light and hydrostatic equilibrium.
The new SIRIS (Scanning InfraRed Imaging System) camera developed at the National Gallery in Lond... more The new SIRIS (Scanning InfraRed Imaging System) camera developed at the National Gallery in London allows highresolution images of paintings to be made in the near infrared region (900-1700 nm). Images of 5000 × 5000 pixels are made by moving a 320 × 256 pixel InGaAs array across the focal plane of the camera using two orthogonal translation stages. The great advantages of this camera over scanning infrared devices are its relative portability and that image acquisition is comparatively rapid-a full 5000 × 5000 pixel image can be made in around 20 minutes. The paper describes the development of the mechanical, optical and electronic components of the camera, including the design of a new lens. The software routines used to control image capture and to assemble the individual 320 × 256 pixel frames into a seamless mosaic image are also mentioned. The optics of the SIRIS camera have been designed so that the camera can operate at a range of resolutions; from around 2.5 pixels per millimetre on large paintings of up to 2000 × 2000 mm to 10 pixels per millimetre on smaller paintings or details of paintings measuring 500 × 500 mm. The camera is primarily designed to examine underdrawings in paintings; preliminary results from test targets and paintings are presented and the quality of the images compared with those from other cameras currently used in this field.
ABSTRACT A Fourier domain (FD) optical coherence tomography (OCT) system is shown to be capable o... more ABSTRACT A Fourier domain (FD) optical coherence tomography (OCT) system is shown to be capable of profilometry with two orders of magnitude better accuracy than the axial imaging resolution of the system. High precision OCT profilometry not only achieves similar accuracy as commercial white light interferometry based profilometers but is also capable of profilometry on complex subsurface structures with multiple interfaces of low reflectance. An accuracy of 55nm was achieved with a ThorLabs SROCT on a lab bench without special anti-vibration devices. This technique has the potential for a range of applications, such as high precision refractive index measurements and simultaneous dynamic monitoring of the interface structure of a drying varnish and the substrate.
While OCT has been applied to the non-invasive examination of the stratigraphy of paint layers in... more While OCT has been applied to the non-invasive examination of the stratigraphy of paint layers in recent years, it has been recognized that the resolutions of commercially available OCT cannot compete in depth resolution with conventional microscopic examination of cross-sections of paint samples. It is necessary to achieve resolutions better than 3 microns to resolve the thinnest layers of paint and varnish. In this paper, we demonstrate a Fourier domain ultrahigh resolution OCT at 810nm with depth resolution of 1.8 u.m in air (or 1.2u.m in varnish or paint).
Optical Coherence Tomography has been successfully applied to the imaging of painted objects in r... more Optical Coherence Tomography has been successfully applied to the imaging of painted objects in recent years. However, a significant limitation is the low penetration depth of OCT in paint because of the high opacity of paint due to either scattering or absorption. It has been shown that the optimum spectral window for OCT imaging of paint layers is around 2.2u.m in wavelength. In this paper, we demonstrate a 1950nm OCT for imaging painted objects using a superfluorescent fiber source at low power.
We present a prototype portable remote multispectral imaging system, PRISMS (Portable Remote Imag... more We present a prototype portable remote multispectral imaging system, PRISMS (Portable Remote Imaging System for Multispectral Scanning), that is lightweight , flexible and without any cumbersome mechanical structure for in situ high resolution colour and spectral imaging of large and inaccessible paintings such as wall paintings. This is the first instrument to be able to image paintings at inaccessible heights in situ from ground level to produce not only high resolution colour images but also multispectral images.
Monthly Notices of the Royal Astronomical Society, Sep 1, 2002
We study the origin of the non-thermal emission from the intracluster medium, including the exces... more We study the origin of the non-thermal emission from the intracluster medium, including the excess hard X-ray emission and cluster-wide radio haloes, through fitting two representative models to the Coma cluster. If the synchrotron-emitting relativistic electrons are accelerated in situ from the vast pool of thermal electrons, then a quasi-stationary solution of the kinetic equation with particle acceleration through turbulence at high energies (>200 keV) naturally produces a population of suprathermal electrons responsible for the excess hard X-ray emission through bremsstrahlung. Inverse Compton scattering is negligible at hard X-ray energies in this case. The radio halo flux density constrains the magnetic field strength to a value close to that of equipartition, ∼1 µG. Alternatively, if the relativistic electrons are injected from numerous localized 'external' sources, then the hard X-rays are best explained by inverse Compton scattering from GeV electrons, and little of the hard X-radiation has a bremsstrahlung origin. In this case, the magnetic field strength is constrained to ∼0.1-0.2 µG. Both models assume that the non-thermal emissions are generated by a single electron spectrum, so that only two free parameters, well constrained by the observed hard X-ray and radio halo spectra, are needed in either case. Measurements of the cluster magnetic field will distinguish between the models.
An optical coherence tomography (OCT) system using a compact fiber source emitting amplified spon... more An optical coherence tomography (OCT) system using a compact fiber source emitting amplified spontaneous emission (ASE) at central wavelength of 1960nm with bandwidth of 40nm is developed to enhance the probing depth in highly scattering material with low water content. Examples of application to paint is used to demonstrate significantly improved penetration depth in high opacity material in the two-micron wavelength regime.
Using non-invasive non-destructive techniques to monitor cultural heritage objects Cultural herit... more Using non-invasive non-destructive techniques to monitor cultural heritage objects Cultural heritage plays a significant role in our identities and well-being. The aim of conservation is to manage change to cultural heritage objects. Non-destructive techniques offer an opportunity to quantify deterioration objectively and at an earlier stage than observation. There are limitations for using the techniques on precious artefacts. This paper examines some of the issues and opportunities through case studies with phased pulse thermography, acoustic emission, Fourier transform infrared spectroscopy and optical coherence tomography, applied to a series of mediaeval Limoges enamel plaques from the Werner Collection, displayed at Rangers House, London.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
As part of a 4-year Cosmology and Particle Astrophysics (CosPA) Research Excellence Initiative in... more As part of a 4-year Cosmology and Particle Astrophysics (CosPA) Research Excellence Initiative in Taiwan, AMiBA − a 19-element dual-channel 85-105 GHz interferometer array is being specifically built to search for high redshift clusters of galaxies via the Sunyaev-Zeldovich Effect (SZE). In addition, AMiBA will have full polarization capabilities, in order to probe the polarization properties of the Cosmic Microwave Background. AMiBA, to be sited on Mauna Kea in Hawaii or in Chile, will reach a sensitivity of ∼ 1 mJy or 7µK in 1 hour. The project involves extensive international scientific and technical collaborations. The construction of AMiBA is scheduled to starting operating in early 2004.
We will discuss the properties and origins of halos and relics including estimates of the cluster... more We will discuss the properties and origins of halos and relics including estimates of the cluster magnetic fields, and present results for a few recently discovered halos and relics. The electrons in the suprathermal high energy tail of the thermal gas distribution are likely to provide the seed particles for acceleration through mergers and turbulences to relativistic energies. These relativistic particles are then responsible for the synchrotron emission of the halos.
The design and experimental method for the use of a novel instrument for lightfastness measuremen... more The design and experimental method for the use of a novel instrument for lightfastness measurements on artwork is presented. The new microfadometer design offers increased durability and portability over the previous, published design, broadening the scope of locations at which data can be acquired. This reduces the need for art handling or transportation in order to gain evidence-based risk assessments for the display of light-sensitive artworks. The instrument focuses a stabilized high powered xenon lamp to a spot 0.25 millimeters (FWHM) while simultaneously monitoring color change. This makes it possible to identify pigments and determine the lightfastness of materials effectively and non-destructively. With 2.59mW or 0.82 lumens (1.7 x10 7 lux for a 0.25mm focused spot) the instrument is capable of fading Blue Wool 1 to a measured 11 ∆E ab value (using CIE standard illuminant D65) in 15 minutes. The temperature increase created by focused radiation was measured to be 3 to 4°C above room temperature. The system was stable within 0.12 ∆E ab over 1 hour and 0.31 ∆E ab over 7 hours. A safety evaluation of the technique is discussed which concludes that some caution should be employed when fading smooth, uniform areas of artworks. The instrument can also incorporate a linear variable filter. This enables the researcher to identify the active wavebands that cause certain degradation reactions and determine the degree of wavelength dependence of fading. Some preliminary results of fading experiments on Prussian blue samples from the paint box of J. M. W Turner (1755-1851) are presented.
PRISMS (Portable Remote Imaging System for Multispectral Scanning) is a multispectral/hyperspectr... more PRISMS (Portable Remote Imaging System for Multispectral Scanning) is a multispectral/hyperspectral imaging system designed for flexible in situ imaging of wall paintings at high resolution (tens of microns) over a large range of distances (less than a meter to over ten meters). This paper demonstrates a trial run of the VIS/NIR (400-880nm) component of the instrument for non-invasive imaging of wall paintings in situ. Wall painting panels from excavated Tang dynasty (618-907AD) tombs near Xi'an were examined by PRISMS. Pigment identifications were carried out using the spectral reflectance obtained from multispectral imaging coupled with non-invasive elemental analysis using a portable XRF.
Journal of Colloid and Interface Science, Apr 1, 2013
In this work, we present the visualization of the internal flows in a drying sessile polymer disp... more In this work, we present the visualization of the internal flows in a drying sessile polymer dispersion drop on hydrophilic and hydrophobic surfaces with Spectral Radar Optical Coherence Tomography (SR-OCT). We have found that surface features such as the initial contact angle and pinning of the contact line, play a crucial role on the flow direction and final shape of the dried drop. Moreover, imaging through selection of vertical slices using optical coherence tomography offers a feasible alternative compared to imaging through selection of narrow horizontal slices using confocal microscopy for turbid, barely transparent fluids.
We correct a mistake in the OCT system sensitivity given in our recent paper [Opt. Express23(3), ... more We correct a mistake in the OCT system sensitivity given in our recent paper [Opt. Express23(3), 1992 (2015) 10.1364/OE.23.00199225836070].
The Array for Microwave Background Anisotropy (AMiBA) is an interferometric array of 19 dishes co... more The Array for Microwave Background Anisotropy (AMiBA) is an interferometric array of 19 dishes co-mounted on a steerable platform and operating at 95 GHz. One of the main scientific aims of AMiBA is to conduct cluster surveys using the Sunyaev-Zel'dovich (SZ) effect. Here we explore the potential of AMiBA as a tailor-made SZ instrument for the study of cluster physics and cosmology via cluster surveys out to the epoch of cluster formation. In particular, we explore the potential of combining AMiBA cluster surveys with the XMM-LSS (Large Scale Structure) survey.
This paper will introduce a new application of Optical Coherence Tomography (OCT) to the monitori... more This paper will introduce a new application of Optical Coherence Tomography (OCT) to the monitoring of vulnerability of rock art monuments in-situ. The porosity of the host rock is an important factor affecting the susceptibility of rock art monuments to decay. Pore characteristics of rocks are one of the main factors that control the intensity of physical deterioration. OCT has
The Technological Study of Books and Manuscripts as Artefacts - Research questions and analytical solution, 2011
ISBN 978 1 4073 0767 1 Front cover image shows a miniature from Bodleian Library manuscript MS Do... more ISBN 978 1 4073 0767 1 Front cover image shows a miniature from Bodleian Library manuscript MS Douce 195 fol. 1r, reproduced with permission from the Bodleian Libraries, University of Oxford.
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