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WO2007003700A1 - Mesure des proprietes optiques et acoustiques de materiaux troubles par un procede photoacoustique de diffusion - Google Patents

Mesure des proprietes optiques et acoustiques de materiaux troubles par un procede photoacoustique de diffusion Download PDF

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Publication number
WO2007003700A1
WO2007003700A1 PCT/FI2006/050287 FI2006050287W WO2007003700A1 WO 2007003700 A1 WO2007003700 A1 WO 2007003700A1 FI 2006050287 W FI2006050287 W FI 2006050287W WO 2007003700 A1 WO2007003700 A1 WO 2007003700A1
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Prior art keywords
photoacoustic
absorber
signals
amplitudes
turbid material
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English (en)
Inventor
Risto MYLLYLÄ
Zuomin Zhao
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00—Features of devices classified in G01N21/00
    • G01N2201/06—Illumination; Optics
    • G01N2201/061—Sources
    • G01N2201/06113—Coherent sources; lasers

Definitions

  • the invention relates to a method and measurement arrangement for measuring optical parameters and composition of turbid materials by pulsed laser radiation.
  • Measuring optical and acoustic parameters of materials is important because it is closely relative to the material composition and property.
  • the techniques based on the integrating sphere (measuring transmission and reflectance), optical diffusion with added a small quality of absorbing material, time-of-flight of photons, and time-resolved stress detection (TRSD) with measuring total diffusive reflectance have been developed to measure optical parameters of various media. Although these techniques provide accurate results, their use in particle applications has some drawbacks.
  • the integrating sphere method is used for measuring a thin layer sample, which method can not apply for thick object.
  • the optical diffusive method with added absorbing material can not be used in non-invasive or on-line measurement.
  • the devices required by time-of-flight technique include an ultra short pulse laser and a single-photon avalanche photodiode which are very expensive. Moreover, these optical methods can not give any acoustic information of material.
  • Photoacoustic techniques are based on the mechanism of optical absorption of studied medium, in which a photoacoustic source (PA) is produced. They are divided into two categories according to their measuring parameters: photoacoustic spectroscopy (PAS) which detects the photoacoustic amplitude produced by the studied object, and time-resolved photoacoustic technique (or time-resolved stress detection TRSD) which determines both stress profile and amplitude.
  • PAS photoacoustic spectroscopy
  • TRSD time-resolved photoacoustic technique
  • both PAS and TRSD techniques will be ineffective be- cause of the photoacoustic effect produced in a studied object is too weak to be detected; for example, when the absorption coefficient of a highly turbid material is very weak or near to zero at study wavelengths, or if a low energy laser is used as the excitation source for low cost and portable purposes.
  • the reference discloses a system for measuring optical absorption properties of materials.
  • the unabsorbed light energy either directly traversed through the material or back scattered from the material, is first detected.
  • the material absorbs a part of the light which the material afterwards transmits as ultrasonic waves. Also this ultrasonic energy is detected.
  • the detected energies are utilized when calculating the absorption coefficient of the studied material.
  • An example of a measuring application in an industrial process is a measurement of the fibre and fines consistencies in paper pulp.
  • the pulp consists of wood cells called fibres, fibre fragments called fines and fillers are added to improve the optical and solidity properties of the final paper product.
  • On-line measuring the pulp consistency during the processes is a requirement for better paper quality, more effective use of raw materials, lower production costs and faster paper machine speeds.
  • the prior art measuring methods are based on detecting the attenuation and scattering of optical signal, attenuation and retardation of microwaves, and changes in mechanical viscosity of pulp slurry. In all these methods, the calibration of the measurement devices is difficult and in a key position. Furthermore, they can not simultaneously give rise to the optical and acoustic properties of materials.
  • An object of the invention is to avoid above-described problems of the prior art and to provide a new, cost effective measuring method and apparatus for measuring optical scattering and absorption and acoustic attenuation properties of a weakly- absorbing material simultaneously, by utilizing photoacoustic phenomenon.
  • the objects of the invention are achieved by a method where a low-energy laser pulse is directed to a weakly-absorbing material, which is to be analyzed.
  • the Ia- ser pulse is partly absorbed in the material causing a photoacoustic signal and partly scattered.
  • a part of the scattered photons is received by an absorber which is in contact with the studied material producing another photoacoustic signal in the absorber. From amplitudes of the photoacoustic signals can be studied what are the scattering and absorption properties of the material.
  • the measuring method according to the invention is called scattering photoacoustic (SPA) technique in this application.
  • SPA scattering photoacoustic
  • An advantage of the invention is that the optical absorption and scattering coefficients of a material can be deduced simultaneously by a one-detector arrange- ment.
  • Another advantage of the invention is that when analyzing weakly-absorbing, highly turbid medium there are two photoacoustic pulses produced by medium, i.e. absorption and scattering, which can be analyzed utilizing detected signal amplitudes.
  • a further advantage of the invention is that only a low-energy laser and an acoustic detector is needed in the measurement.
  • a further advantage of the invention is that it reduces transducer bandwidth requirements when compared with TRSD.
  • a further advantage of the invention is that it can simultaneously study optical and acoustic properties of the analyzed material, simply by applying another same absorber. An example is to determine fibre and fines consistencies of pulp.
  • Yet a further advantage of the invention is that the measurement arrangement is simple and low cost for on-line apparatus in pulp measurement.
  • the idea of the invention is as follows. Huge amounts of photons scatter out from the laser illuminated region in the highly turbid material. These scattering photons also record optical properties of the studied material. These photons can advantageously be received by at least one disk absorber with high absorption coefficient at study wavelengths. Therefore, a photoacoustic source is produced also at the reception surface of the absorber. This is called scattering photoacoustic source.
  • Fig. 1 a shows a schematical representation of a measurement arrangement according to the first embodiment of the invention
  • Fig. 1 b shows a schematical representation of a measurement arrangement according to the second embodiment of the invention
  • Fig. 1 c shows schematically received photoacoustic signals according to the second embodiment of the invention
  • Fig. 2 shows an exemplary measurement arrangement according to the invention
  • Fig. 3a shows an example of received signals when a PVDF transducer is utilized
  • Fig. 3b shows an example of received signals when a PZT transducer is util- ized
  • Fig. 4 shows the correlation between V S p A and intralipid concentration
  • Fig. 6 shows ln(rV)-r lines measured in intralipid samples by the PZT transducer
  • Fig. 7 shows ln(rV)-r lines measured in intralipid samples by the PVDF transducer
  • Fig. 8a shows measured relationship between scattering and V PA in ink- intralipid mixes
  • Fig. 8b shows measured relationship between scattering and V SPA in ink- intralipid mixes
  • Fig. 9a shows measured relationship between absorption and V PA in ink- intralipid mixes
  • Fig. 9b shows measured relationship between absorption and V SPA in ink- intralipid mixes
  • Fig. 10 shows measured signals produced in three pulp samples
  • Fig. 1 1 a shows measured amplitudes of V spa i, versus fines concentration
  • Fig. 1 1 b shows measured amplitudes of V pa , versus fines concentration
  • Fig. 1 1 c shows measured amplitude ratios of V S p a2 /V S p a i, versus fines concentration
  • Fig. 12a shows measured amplitudes of V spa i, versus fiber consistency
  • Fig. 12b shows measured amplitudes of V pa , versus fiber consistency
  • Fig. 12c shows measured amplitude ratios of V spa 2/V spa i, versus fibre consistency
  • FIG. 1 a depicts schematically an advantageous embodiment of the present invention.
  • a turbid sample 12 is loaded in a cuvette 10, which is illuminated by a pulsed laser beam 1 1.
  • a part of optical energy is absorbed by the sample 12.
  • the scattered photons 19a are absorbed by an absorber 14. This produces photoacoustic source 16b on a surface of the absorber 14.
  • an arrow 19c is depicted that an acoustic wave propagates from the acoustic source 16b through the absorber 14 to a detector 17.
  • the shape of photoacoustic source 16a is approximately spherical-like shape.
  • measured signal amplitude can be described by
  • R a is the source size in the direction of signal reception.
  • E a is the absorbed light energy in source, which is proportional to the absorption coefficient ⁇ a .
  • optical transport follows the diffusion theory. If the energy of a spot source in an infinite medium is E and the pulse duration is longer than the order of 1 ns, the energy fluence can be determined by steady-state diffusion theory
  • the absorber 14 has very high absorption coefficient in study wavelengths and the shape of photoacoustic source 16b is plane-like one. Therefore, the PA signal amplitude generated by photoacoustic source 16b is described by
  • V SPA becomes
  • ⁇ n(rV SPA ) -p ⁇ a ⁇ s ' ⁇ r + ln ⁇ 4 - exp(- iJ ⁇ j ⁇ Tfy, ' ⁇ ( 8 )
  • K can be calibrated out by a sample with known absorption and scattering coefficient.
  • reduced scattering coefficient ⁇ s ' can be determined by scattering photoacoustic signal.
  • Fig 1 b which is a second advantageous embodiment of the invention, there are two absorbers, references 14 and 15, which are located on the opposite side walls of the cuvette 10.
  • the absorbers 14 and 15 are equally located compared to the laser beam 1 1.
  • Part of photons of the laser beam 1 1 are scattered out in the sample, references 19a and 19b. Therefore, three photo- acoustic sources are produced.
  • the first one is in the turbid sample, reference 16a.
  • the second source, reference 16b is in the first absorber 14.
  • the third source, reference 16c is in the second absorber 15, which is located on the other side wall of the cuvette 10.
  • the third acoustic source 16c produces an acoustic wave 18.
  • V spa r can be called a first acoustic signal
  • V pa can be called a second acoustic signal
  • V spa2 can be called a third acoustic signal.
  • V spa1 depicts a signal generated by the photoacoustic source 16b on the first absorber 14.
  • V spa2 depicts an acoustic signal 18 generated by the photo- acoustic source 16c on the second absorber 15.
  • Signal V pa depicts an acoustic signal 13 generated by the photoacoustic source 16a in the turbid media 12.
  • V pa can be expressed as
  • ⁇ a absorption coefficient of the sample
  • R is the radius of the cylindrical source
  • E is the pulse laser energy in the source
  • r 0 is the distance between the source 16a and the detector 17.
  • V pa is described by equation (1 ), rewritten below:
  • Equations (10) and (11 ) can be used to qualitative describe the photoacoustic signal amplitude produced in scattering suspensions with weak absorption. If the scattering concentration is very low, the photoacoustic source 16a is cylindrical- like and its radius is near equal to incident laser beam. When the concentration in- creases, more and more scattering photons are scattered out from the source beam, causing an increase of source radius and a decrease of energy density in the beam. Therefore, based on equation (10), V pa will decline accordingly. Along with the concentration increases, the source radius continues to increase but the length of source is shortened, forming the spherical-like source.
  • the photoacoustic sources 16b and 16c produced on two absorbers' reception surfaces are plane-like, because the absorbers 14 and 15 are highly absorbing material.
  • the signal amplitude can be described by equation (6). If ⁇ s ' is not too high to satisfy
  • V spa increases monotonously with ⁇ s ' ⁇ otherwise, V spa will be decreased with higher ⁇ s '.
  • both acoustic sources 16b and 16c produced by the absorbers should have same intensity.
  • the acoustic wave 18 emitted by the second absorber 15 will be attenuated by the sample before accepted by the detector 17, whereas the acoustic wave pro- prised by absorber 14 is not attenuated.
  • the ratio of signal amplitudes V spa 2/V spa i can be used to evaluate also the acoustic attenuation of the sample.
  • V pa , V spa1 , V spa2 and calculating V spa2 IV spa1 it is possible to evaluate the optical scattering, optical absorption and acoustic attenua- tion of the sample and therefore to measure its composition.
  • Figure 2 shows an advantageous embodiment of a measurement arrangement according to the first embodiment of the invention.
  • a diode pumped Q-switched Nd:YAG laser (model LCS- DTL- 1 12QT, LASER-COMPACT Co. Ltd) is used as exciting source, reference 21.
  • the duration of each light pulse is about 14 ns.
  • the output pulse energy is 2 ⁇ J at 1064nm and 1 ⁇ J at 532 nm wavelengths, respectively.
  • the laser beam 1 1 is projected on the incident window of a cuvette 10 where the diameter of the light spot is focused about 0.6 mm.
  • the cuvette has thickness of 30 mm, width of 30 mm and height of 40 mm. A small hole and a valve located on the bottom of cuvette are used to replace the samples without moving the cuvette.
  • a prism 23 after lens 22 separates the spots with different wavelength.
  • a filter 28 chooses the illuminated wavelength and a stop 25 is used to keep away the remnant pumping light.
  • a detector 27, comprising a piezoelectric ultrasonic transducer connected directly with a preamplifier, is acoustically contacted with an absorber 24 which is embedded in a side wall of the cuvette 10. The thickness of the ab- sorber 24 is 3 mm and its diameter is 8 mm. On the surface of the absorber 24 the scattered photons produces an acoustic source 26.
  • Two kinds of piezoelectric transducers are advantageously used.
  • One is made of PVDF polymer film (Polyvinylidene fluoride) with thickness of 52 ⁇ m and active di- ameter of 5 mm.
  • Another is made of PZT ceramic disk (Lead Zirconate Titanate) with both thickness and diameter of 4 mm.
  • the device diameters of both transducers are 6 mm and 10 mm, respectively.
  • a preamplifier included in the detector 27 has a gain of 40 dB and a bandwidth from 150 kHz to 3 MHz.
  • a translation stage (not shown in Fig 2) is used to change the transversal distance between the exciting light spot 11 and the detector 27.
  • the output from the detector is connected to a digital oscilloscope 29 to display and store the data. Because PVDF transducer has lower response than PZT one, another amplifier with 60 dB gain (not shown in Fig.2) is added if necessary.
  • the measured and stored photoacoustic data can advantageously be conveyed from the digital oscilloscope 29 to a computer (not shown in Figure 2) for further data processing.
  • a computer not shown in Figure 2 for further data processing.
  • the scattered photons 19a are absorbed by one absorber 14.
  • 10%-lntralipid ® suspension (Fresenius Kab. AB., Uppsala, Sweden) is used as a scattering material 12.
  • the diameter of 99% scattering particles in the suspension is in the range of 25 nm to 500 nm.
  • the absorption coefficient ⁇ a of suspension is low, approximately equal to that of pure water in near infrared wavelength range. It is a popular tissue scattering phantom in biomedical research.
  • the absorption material used in this experi- ment is a kind of Chinese ink, which is added into the diluted suspensions to adjust the absorption property of the samples. The scattering effect of the ink is too small to be observed at the study wavelength.
  • V SPA The measured relationship between V SPA and intralipid concentration is shown in Figure 4, whereas the theoretical forecast is illustrated in Figure 5. It can be seen that they are identical very well, because the reduced scattering coefficient ⁇ s ' is proportional to intralipid concentration (when the concentration is lower than 2%). It can be seen that V SPA quickly rises at first, and then gradually falls with concentration increasing. This is due to that water matrix has a definite absorption (0.0115 mm "1 ) and more multiple scattering events happen in the higher concentration samples. At a definite range of concentration from 0.05% to 0.3% in Fig 4, there is an approximately linear relationship between V SPA and the reduced scattering coefficient ⁇ s '.
  • Table 1 also lists results from our optical measurements as well as values deduced from van Staveren's results (Appl. Opt. 30, 4507-4514, 1991 ). It reveals that the results are in good agreement, except for 5% intralipid. This is because van Staveren's measurements used lower intralipid concentrations. As for high density samples (>2%), ⁇ s ' does not increase linearly with intralipid concentration (Bondani, J. Opt. Soc. Am. B20, 2383-2388, 2003); therefore, the result deduced from van Staveren is not valid.
  • the transducer's diameter is larger than the PIN diode used in our measurement, the misalignment between the transducer and the light spot is greater for high density intralipids. As a result, the transducer records smaller values than the PIN diode.
  • Figure 2 illustrates the measurement, in which the incident laser beam was at a distance of 16 mm from the absorber's reception surface.
  • a 0.04% ink solution was loaded into the cuvette, followed by successive injections of different amounts of 10%-intralipid.
  • Figures 8a and 8b record the signal amplitudes of V PA and V SPA - TO obvert the absorption of the signals, the sample in the cuvette was replaced by a 1 % intralipid suspen- sion, and different amounts of ink solution were successively added into the cuvette. This caused an absorption increase in the sample.
  • the corresponding changes in signal amplitudes of V PA and V SPA are shown in Figures 9a and 9b.
  • V PA decreases steeply when the reduced scattering coefficient is less than 0.2 mm "1 .
  • V PA plateaus as the reduced scattering coefficient varies, which is a very useful characteristic, as shall be demonstrated below.
  • V SPA in Figure 8b is similar to that shown in Figure 4, measured in intralipid suspensions at 1064 nm.
  • Figures 9a and 9b show that, when the concentration or absorption coefficient of ink increases, V PA increases linearly, while V SPA decreases very quickly and approaches zero.
  • ⁇ a and ⁇ s ' can be measured using both V PA and V SPA - TO illustrate this, we used two samples.
  • Sample 1 contained 35 ml of 1.5%-intralipid mixed with 20 ⁇ l of ink; thus, the ink concentration of the sample was 0.057%.
  • Sample 2 on the other hand, consisted of 35 ml of 0.5%-intralipid with an ink concentration of 0.067%.
  • the effective attenuation coef- ficients ⁇ eff (same as the slope of ln(rV S pA)-r line) of the two samples were 0.3655 and 0.2527, respectively, measured by the method described above.
  • the samples' absorption coefficient they can be deduced as below.
  • V PA has a linear relationship with ⁇ a (or ink concentration). Although measured in 1 % intralipid-ink mixes, it can be assumed that the relationship holds for suspensions with intralipid content higher than 0.3%. In this case, V PA remains unchanged even if the intralipid content varies, as shown in Figure 8a.
  • ⁇ s ' can be calculated from ⁇ eff and ⁇ a .
  • Table 2 lists in brackets the predicted absorption coefficient for ink and the reduced scattering coefficient for intralipid. It can be seen that the measured values are almost identical with the predicted ones. So in conclusion, the experiments described above demonstrate that the SPA method allows the direct deduction of the absorption and reduced scattering coefficient of highly turbid materials. Table 2. Measured optical coefficients of two samples at 532 nm; the values in the brackets indicate predicted values.
  • the scattering photoacoustic technique is utilized in pulp measurement.
  • two absorbers references 14 and 15 in Fig 1 b
  • one acoustic transducer 17 we can measure three photoacoustic signals V spa1 , V pa and V spa2 simultaneously. With these three signals it is possible to simultaneously study the forward optical scattering, transverse optical scattering, and acoustic attenuation of pulp suspension.
  • the scattered photons 19a and 19b are absorbed by two absorbers 14 and 15.
  • Samples to be tested are produced from Thermo-mechanical pulp (TMP).
  • TMP Thermo-mechanical pulp
  • the TMP was fractionated by Bauer-McNett fractionator according to SCAN-standard 6:69.
  • the finest fraction, passing through the 200 wire mesh was then subsequently filtered through 400 wire mesh. This results the fine fraction consisting of particles with sizes varying between 30 and 74 ⁇ m.
  • the long fiber fraction used in this study consists of the fibers that passed through the 48 wire mesh from TMP.
  • the length of fibers is about 1-3 mm, diameter is in the order of 10s micron.
  • the fractions were mixed in different proportions, resulting in a range of fines and fiber contents in samples.
  • the pulp sample is named as x%_y%, meaning it consists of x% fibers and y% fines.
  • the measurement system is depicted in Fig 2 with an exception of the second absorber 15 of Fig 1 b, which is added to the arrangement of Fig 2.
  • the typically recorded signals are shown in Figure 10, where there are three signal curves produced by samples 0.5%_0, 0.5%_0.125% and 0.5%_0.25%, respectively.
  • For every signal there are three pulses with amplitudes of V spa1 , V pa and V spa2 , produced in absorber 14, the sample 16a, and absorber 15, respectively.
  • the time delay between the acoustic pulses is depended upon the distance between them and acoustic speed in the sample 12. It can be seen that, when the fines content increases, V spa i, V pa and V spa 2 will be changed.
  • Figures 1 1 a-c give raise to the values of V S p a i, V pa , and to an amplitude ratio V spa2 IV S p a1 produced in pure fines.
  • Figures 12a-c give raise to the values of V spa1 , V pa , and to an amplitude ratio V spa2 IV spa1 produced in pure fibers.
  • V spa1 increases mono- tonically while both V pa and V spa2 IV spa1 approximately linearly falls with fibre consistency increase.
  • fibre flocks may lead different optical and acoustic properties in different location of a sample.
  • the processes of fibre flocks forming and fines attaching or depositing may cause a continuous variation of the sample property. These factors result an apparent measurement deviation and uncertainty.
  • increasing the measurement times and averaging the results will improve the ability of sample identification.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

L'invention concerne un procédé et un ensemble de mesure utilisés pour mesurer des propriétés optiques et acoustiques d'un matériau trouble (12). Le procédé de l'invention consiste à faire passer une impulsion laser basse énergie pulsée (11) dans ledit matériau (12), ce qui permet de créer dans celui-ci des photons diffusés (19a, 19b) et une source photoacoustique (16a) qui transmet un signal photoacoustique (13). Lesdits photons diffusés sont reçus par des absorbeurs (14, 15) qui convertissent les photons reçus en deux autres signaux photoacoustiques. Les trois signaux photoacoustiques sont détectés par un détecteur (17). Par modification de la distance entre l'absorbeur (14) et le faisceau laser incident (11), on peut déduire le coefficient d'absorption µa et le coefficient de diffusion réduite µs' du matériau trouble (12). Le rapport d'amplitude des deux signaux produits par les absorbeurs (14, 15) est proportionnel à l'atténuation acoustique du matériau trouble.
PCT/FI2006/050287 2005-07-06 2006-06-28 Mesure des proprietes optiques et acoustiques de materiaux troubles par un procede photoacoustique de diffusion Ceased WO2007003700A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP06764526A EP1910803A1 (fr) 2005-07-06 2006-06-28 Mesure des proprietes optiques et acoustiques de materiaux troubles par un procede photoacoustique de diffusion

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FI20055390 2005-07-06
FI20055390A FI20055390A0 (fi) 2005-07-06 2005-07-06 Samean materiaalin optisten ja akustisten ominaisuuksien mittaaminen sirontaa hyödyntävällä fotoakustisella menetelmällä

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Cited By (3)

* Cited by examiner, † Cited by third party
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EP2002784A1 (fr) * 2007-06-11 2008-12-17 Canon Kabushiki Kaisha Appareil d'imagerie d'informations intra-vitales
WO2010030043A1 (fr) * 2008-09-12 2010-03-18 Canon Kabushiki Kaisha Appareil de mise en images d'informations biologiques
WO2021144502A1 (fr) * 2020-01-14 2021-07-22 Valmet Automation Oy Appareil et procédé de mesure de suspension s'écoulant dans un tube de fractionnement

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WO2004086965A1 (fr) * 2003-04-01 2004-10-14 Glucon Inc. Procede d'analyse photoacoustique et appareil
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WO2004086965A1 (fr) * 2003-04-01 2004-10-14 Glucon Inc. Procede d'analyse photoacoustique et appareil

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2002784A1 (fr) * 2007-06-11 2008-12-17 Canon Kabushiki Kaisha Appareil d'imagerie d'informations intra-vitales
US8396534B2 (en) 2007-06-11 2013-03-12 Canon Kabushiki Kaisha Intravital-information imaging apparatus
WO2010030043A1 (fr) * 2008-09-12 2010-03-18 Canon Kabushiki Kaisha Appareil de mise en images d'informations biologiques
JP2010088873A (ja) * 2008-09-12 2010-04-22 Canon Inc 生体情報イメージング装置
WO2021144502A1 (fr) * 2020-01-14 2021-07-22 Valmet Automation Oy Appareil et procédé de mesure de suspension s'écoulant dans un tube de fractionnement
US12325957B2 (en) 2020-01-14 2025-06-10 Valmet Automation Oy Apparatus for and method of measuring suspension flowing in tube fractionator

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Publication number Publication date
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EP1910803A1 (fr) 2008-04-16

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