CN1963420A - A method for measuring liquid phase micro-area temperature - Google Patents

Abstract

The method of the present invention measurement micro- system temperature of liquid phase, it is characterized in that the emulsion or powder temperature probe bead of polystyrene or silica are moved to microcell to be measured and are accurately positioned using optical tweezer or micropin, temperature probe bead is discharged, statistical average is done to bead Brownian movement shift value in the δ t time using image capturing system and obtains its Jun Fangzhi amp; amp; amp; lt; r2 amp; gt; Ave is substituted into and is solved formula , the temperature value in region to be measured can be obtained; In formula, K is Boltzmann constant, and T is thermodynamic temperature, and d is the movement dimension , amp; amp of particle Brownian movement; amp; lt; r2 amp; gt; Ave is the mean square displacement value of particle Brownian movement in δ t time interval, and a is particle radius, and η 0, Δ W are the characterisitic parameter of liquid. It may be implemented using the method for the present invention to the accurate positioning in certain region inside microbody system and high spatial resolution measurement. This method can measure any liquid phase substance for having certain visibility, all improve to some extent in terms of thermometric spatial resolution is low, object is limited, narrow range, temperature probe can be to systems compared with the prior art.

Description

A kind of method of measuring liquid phase micro-area temperature

Technical field:

The invention belongs to the temperature measurement technology field, particularly the liquid phase microbody is the measuring method of temperature.

Background technology:

By retrieval, existing measurement liquid phase microbody is that method of temperature mainly contains:

Holland " chromatogram " (J.Chromatogr.A, 1999, the 838th volume, that the 157-165 page or leaf) introduces a kind ofly is close to the outside thermometry of system of extracapillary foreskin with the microprobe thermopair, and its measured temperature is the mean value of system, can not reflect local temperature variation in the system, in addition, this method belongs to contact type measurement, and the thermal capacitance of temperature element itself will inevitably influence the temperature of measuring object, is difficult to truly reflect the temperature of system.

Holland " sensing and braking " (Sens.Actuators A, 2000, the 84th volume, the 11-17 page or leaf) introduced between physical parameters such as a kind of electric current, conductivity, electroosmotic flow speed and electrophoretic mobility of utilizing liquid and temperature and exist the characteristics of fixed relationship to know method of temperature indirectly by inference, its measured temperature also is the mean value of system outside, again because the computing formula used will can when actual test condition meets in the method, promptly system running state and environment there are certain requirement, have caused the limitation of measuring in the practice.

Germany " red, orange, green, blue, yellow (ROGBY) " (Chromatographia,, the 33rd volume, 445-448 page or leaf in 1992) absorption spectroscopy introduced need add the temperature-sensitive dyestuff, this not only can influence the performance of tested systems, also can be because of the narrow scope that limits its measurement of the color change interval of dyestuff itself.

U.S.'s " analytical chemistry " (Anal.Chem.,, the 65th volume, 293-298 page or leaf in 1993) has reported Raman spectroscopy, but it is suitable for having the temperature survey of the system of Raman diffused light spectral property.

Be published in Germany's " the fluid experiment is learned " (Exp.Fluids, calendar year 2001, the 30th volume, the 190-201 page or leaf) thermochromic liquid crystal method, its temperature-measuring range is narrow, only be 0.5～5 ℃, and the liquid crystal microcapsule size that is used for the temperature detection can't apply to the measurement of space scale less than its yardstick usually at tens micrometer ranges.

In sum, existing liquid phase microbody is a thermometry, have that the thermometric spatial resolution is low, temperature-measuring range is narrow, temperature probe can impact and deficiency such as the thermometric object is limited system, can't realize the accurate location and the high resolving power in inner certain zone of microbody system are measured.

Summary of the invention:

It is method of temperature that the present invention proposes a kind of measurement liquid phase microbody, by by the micromechanics operational means temperature probe accurately being positioned zone to be measured, to realize inner certain regional high spatial resolution measurement to this microbody system.

The present invention measured the method for liquid phase micro-area temperature, it is characterized in that: by 1: 10 ³～1: 10 ⁸Mass ratio the emulsion or the powder of temperature probe bead joined in the testing sample, evenly mix the back and move in the sample cell, place on the microscope stage; Adopt micromechanics to control means the temperature probe bead is moved to microcell to be measured and accurate location, the temperature probe bead is discharged, utilize image capturing system record bead to do the image of free Brownian movement; Through graphical analysis, obtain the shift value of bead Brownian movement in a series of δ t time intervals, bead Brownian movement shift value in 500～1500 groups the δ t time interval is done statistical average draw its mean square value＜r ²＞ _Ave, substitution formula (1)

$\frac{K\&CenterDot;T\&CenterDot;d\&CenterDot;\mathrm{\&delta;<figure-callout\; id="3"\; label="t"\; filenames="A20051009537400081.png"\; state="\{\{state\}\}">t</figure-callout>}}{3\mathrm{\&pi;a}<{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="A20051009537400081.png"\; state="\{\{state\}\}">r</figure-callout>}}^2{>}_{\mathrm{ave}}}={\mathrm{\&eta;}}_0{e}^{\frac{\mathrm{\&Delta;W}}{\mathrm{KT}}}---\left(1\right)$

In the formula (1), K is a Boltzmann constant, and T is a thermodynamic temperature, and d is the motion dimension of particulate Brownian movement,＜r ²＞ _AveBe the mean square displacement value of particulate Brownian movement in the δ t time interval, a is a particle radius, η ₀, Δ W is the characterisitic parameter of liquid; Wherein the numerical value of δ t can draw divided by the picture totalframes that writes down according to the T.T. of document image; Find the solution this formula (1), can obtain the temperature value in zone to be measured.

The described material that is used to prepare the temperature probe bead comprises that the density with testing sample differs ± 7% with the polystyrene interior, that physical property is stable or silicon dioxide emulsion or powder.

The described temperature probe bead is moved with pinpoint micromechanics controlled means, comprises light tweezer or micropin.

All relevant with the temperature character of the coefficient of viscosity that temp measuring method of the present invention is based on particulate Brownian movement severe degree and liquid is carried out thermometric, and the spatial resolution of this method depends on the accurate location of temperature probe and the range size of Brownian movement thereof; The accurate location of temperature probe is controlled means by micromechanicss such as light tweezer, micropins and is realized that its precision depends on the precision that micromechanics is controlled; The range size of its Brownian movement is relevant with the temperature and the coefficient of viscosity of the size of selected particle, object to be measured, the suitable particle of preferred dimension as the case may be during practical application; The trueness error of measurement result mainly comes from statistical error, this just requires after the influence that the severe degree of the size of the selected temperature probe bead of concrete consideration, Brownian movement is brought, do statistical confidence and error analysis again, to estimate rational information acquisition amount, as reaching 95% degree of confidence and less than 5% error, even the measuring accuracy of this method reaches 0.5 ℃, error is less than 3% requirement, and the information acquisition amount should be 500～1500 groups; The mass ratio that adds the thermometric bead in the testing sample will specifically estimate according to the bead emulsion of selecting for use or the concentration of powder, so that the shared volume fraction of thermometric bead is 10 in the sample for preparing ^-7～10 ^-5Between get final product, the shared volume fraction of temperature probe bead is 10 in the testing sample as making ^-6The time, then the mass ratio of the temperature probe bead emulsion of Jia Ruing or powder and testing sample is 1: 10 ³～1: 10 ⁸

Compared with prior art, because the present invention adopts micromechanics to control means and will differ with the density of testing sample at ± 7% stable with interior, physical property, regular shape, big or small homogeneous and ganoid temperature probe bead and accurately be positioned microcell to be measured, having solved existing liquid phase microbody is the problem that temperature-measuring range is subject to temperature probe in the temperature survey; Because the present invention utilizes micromechanics to control means and accurately locatees temperature probe, realized the temperature survey of high spatial resolution; Particularly, adopt the inventive method can realize contactless temperature-measuring if be detected when containing the component that can be used as temperature probe in the system; Because in very big temperature range, the Brownian movement phenomenon that thermal motion causes all can be accomplished accurate surveying in various liquid, so this method can be measured any liquid phase substance that certain visibility is arranged, than prior art is low in the thermometric spatial resolution, object is limited, narrow range, temperature probe can all improve to some extent to aspects such as system impact.

Description of drawings:

Fig. 1 is the nanometer optical tweezer system experimental device structural principle synoptic diagram of Typical Disposition.

Embodiment:

Embodiment 1:

Present embodiment adopts the light tweezer to control means as micromechanics and accurately locatees temperature probe, and a certain micro-area temperature to water and ethanol water under different temperatures is measured.

Fig. 1 has provided a kind of nanometer optical tweezer system and device that present embodiment adopts, it is by laser instrument 1, (main parts size has double color reflection mirror 6 to microscope, 100 times of oil immersion objectives 7, halogen illuminating lamp 10, beam splitter prism 11), piezoelectric scanning platform 8, digital camera 12, optical elements such as computer control system 13 and catoptron are formed: employing power is 10mW, wavelength is that helium-neon (He-Ne) laser instrument 1 of 632.8nm is as light tweezer light source, after the laser of output expands bundle and collimation lens 3 collimation focusing through beam expanding lens 2, again through catoptron 4 and catoptron 5 reflections, be coupled into the optical channel of inverted microscope, light beam reflects again after 100 * oil immersion objective the last 7 assembled through double color reflection mirror 6, form optical gradient forces potential well, i.e. light tweezer in the emergent light focal position; The piezoelectric scanning platform 8 of being controlled its three-dimensional motion by computer program (automatic or manual) is set on the sample stage of microscopic system, so that move relative to the three-dimensional of object lens, realize that the light tweezer controls the accurate location of object, mobile etc. by its control sample cell 9 placed thereon; On microscopical observation passage, added image acquisition instrument digital camera (CCD) 12, the signal of its collection can be realized all little real-time monitored of controlling process after being transferred to computing machine 13.

The neutral attenuator group of helium-neon laser Shu Keyong changes light intensity, to adapt to the needs of different measuring scope.The measurement of little displacement of ball is with analysis software dynamic micro-image to be carried out correlation analysis to realize.

After putting up the nanometer optical tweezer system equipment by above-mentioned Experimental equipment, the polystyrene sphere emulsion (can directly buy from Duke scientific company etc.) that will contain as temperature probe by 1: 10000 mass ratio joins the testing sample, so that the shared volume fraction of polystyrene sphere is 10 in the testing sample ^-6, promptly can begin temperature test after the testing sample after the modulation moved into the sample cell of device-specific.

Earlier catch thermometric " probe " bead during measurement with the light tweezer, use again by the piezoelectric scanning platform 8 of computing machine 13 programmed control (automatic or manual) and control sample cell 9 moving with respect to object lens, after the thermometric " probe " of being caught moved to the tiny area of temperature to be measured, close the black out tweezer, allow bead do free Brownian movement, meanwhile with image capturing system observation and record thermometric " probe ".

In order to reduce of the influence of light tweezer as far as possible to the bead diffusion motion, promptly eliminate light tweezer light source to being detected the influence that system temperature may cause, close the free Brownian movement that began the tracking measurement bead in back 2 seconds again at the light tweezer, stop again during away from focal plane of lens measuring up to bead.The time of tracking measurement is generally 20 seconds, and in such time span, the free Brownian movement of bead is at about 5 μ m of change in location scope longitudinally.For obtaining the Brownian movement shift value of sufficient amount, repeatedly repeat aforesaid operations, promptly catch " probe " bead again, move back to and treat temperature measuring area, and follow the tracks of its Brownian movement.Handle with the bead Brownian movement image that related operation method image analytical method logarithmic code camera (CCD) is gathered, obtain the two-dimentional Brownian movement shift value that a series of adjacent two frame times are spaced apart the bead of Δ t.A large amount of Brownian movement shift values is carried out statistical average, draw its mean square value＜r ²＞ _Ave, substitution $\frac{K\&CenterDot;T\&CenterDot;d\&CenterDot;\mathrm{\&delta;<figure-callout\; id="3"\; label="t"\; filenames="A20051009537400081.png"\; state="\{\{state\}\}">t</figure-callout>}}{3\mathrm{\&pi;a}<{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="A20051009537400081.png"\; state="\{\{state\}\}">r</figure-callout>}}^2{>}_{\mathrm{ave}}}={\mathrm{\&eta;}}_0{e}^{\frac{\mathrm{\&Delta;W}}{\mathrm{KT}}}=\mathrm{\&eta;}$ Formula draws the relational expression of system coefficient of dynamic viscosity and temperature, finds the solution the temperature value that this formula gets zone to be measured.The derivation of this formula can be referring to " Thermodynamics and Statistical Physics " (Wang Zhicheng writes, Beijing: Higher Education Publishing House, the 386th page of 1980 (calendar year 2001 reprints) version) and " calorifics " (Li Chun etc. write, Beijing: People's Education Publishing House, 1978 editions the 313rd page).

With the pure water is that example uses the method that is proposed to carry out temperature survey:

$\mathrm{\&eta;}=\frac{K\&CenterDot;T\&CenterDot;2\&times;0.11}{3\mathrm{\&pi;}\&CenterDot;0.5\&times;{10}^{-6}\&times;0.2538\&times;{10}^{-12}}=0.02483\&CenterDot;e^{\frac{0.3555\&times;{10}^{-19}}{\mathrm{KT}}}$

Wherein, η ₀=0.02483 and Δ W=0.3555 * 10 ^-19Be η=182.3 * 10 of water during with known T=273.15K ^-6Kgfs/m ²And η=133.1 * 10 during T=283.15K ^-6Kgfs/m ²Try to achieve.

Find the solution following formula and get T=302.5K, the temperature of the interior microcell to be measured of sample cell is 29.35 ± 0.1 ℃ when promptly testing.

Be that 60% ethanol water uses the method that is proposed to verify to quality percentage composition under the same experiment condition again:

$\mathrm{\&eta;}=\frac{K\&CenterDot;T\&CenterDot;2\&times;0.11}{3\mathrm{\&pi;}\&CenterDot;0.5\&times;{10}^{-6}\&times;0.2283\&times;{10}^{-12}}=0.0462\&CenterDot;e^{\frac{0.3494\&times;{10}^{-19}}{\mathrm{KT}}}$

Wherein, η ₀=0.00462 and Δ W=0.3494 * 10 ^-19Be η=260.3008 * 10 of water during with known T=293.15K ^-6Kgfs/m ²And η=149.8916 * 10 during T=313.15K ^-6Kgfs/m ²Try to achieve.

Find the solution following formula and get T=303.3K, the temperature of the interior microcell to be measured of sample cell is 30.15 ± 0.1 ℃ when promptly testing.

To above measurement result, be that ambrose alloy-nickel aluminium K type thermocouple thermometer has carried out confirmatory measurements, unanimity as a result with the about 0.5mm of probe size, material; In addition, water and ethanol water when also with this method T being 278K, 318K are measured, and its result is consistent with the measurement result of ambrose alloy-nickel aluminium K type thermocouple thermometer.

The measurement liquid phase microbody that the present invention proposes is a method of temperature, can realize accurate measurement to inner certain regional temperature of microbody system, having solved existing liquid phase microbody is the problem that temperature-measuring range is subject to temperature probe in the temperature survey, utilize micromechanics to control means and accurately locate the measurement of temperature probe realization high spatial resolution, and after specifically pure water and ethanol water having been carried out implementing checking, analyze under used experiment condition the measurement space resolution of this method be 10 * 10 * 5 μ m ³When in being detected system, containing the component that can be used as temperature probe, can realize contactless temperature-measuring; In addition, the measuring object of this method can be any liquid phase substance that certain visibility is arranged, temperature-measuring range can not be restricted because of used probe, thereby, than prior art this method is low in the thermometric spatial resolution, object is limited, narrow range, temperature probe can all improve to some extent to aspects such as system impact.

Claims (3)

1, a kind of method of measuring liquid phase micro-area temperature is characterized in that: by 1: 10 ³～1: 10 ⁸Mass ratio the emulsion or the powder of temperature probe bead joined in the testing sample, evenly mix the back and move in the sample cell, place on the microscope stage; Adopt micromechanics to control means the temperature probe bead is moved to microcell to be measured and accurate location, the temperature probe bead is discharged, utilize image capturing system record bead to do the image of free Brownian movement; Through graphical analysis, obtain the shift value of bead Brownian movement in a series of δ t time intervals, bead Brownian movement shift value in 500～1500 groups the δ t time interval is done statistical average draw its mean square value＜r ² _Ave, substitution formula (1)

$\frac{K\&CenterDot;T\&CenterDot;d\&CenterDot;\mathrm{\&delta;t}}{3\mathrm{\&pi;a}{<r^2>}_{\mathrm{ave}}}={\mathrm{\&eta;}}_0{e}^{\frac{\mathrm{\&Delta;W}}{\mathrm{KT}}}---\left(1\right)$

In the formula (1), K is a Boltzmann constant, and T is a thermodynamic temperature, and d is the motion dimension of particulate Brownian movement,＜r ² _AveBe the mean square displacement value of particulate Brownian movement in the δ t time interval, a is a particle radius, η ₀, Δ W is the characterisitic parameter of liquid; Wherein the numerical value of δ t can draw divided by the picture totalframes that writes down according to the T.T. of document image; Find the solution this formula (1), can obtain the temperature value in zone to be measured.

2, measure the method for liquid phase micro-area temperature according to claim 1, be characterised in that the described material that is used to prepare the temperature probe bead, comprise that the density with testing sample differs ± 7% with the polystyrene interior, that physical property is stable or silicon dioxide emulsion or powder.

3, measure the method for liquid phase micro-area temperature according to claim 1, be characterised in that the described temperature probe bead is moved with pinpoint micromechanics control means, comprise light tweezer or micropin.

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