CN104007405A - Magnetic susceptibility measuring device and method based on magneto-Archimedes levitation - Google Patents

Abstract

The invention provides a magnetic susceptibility measuring device based on magneto-Archimedes levitation. The device comprises a magnetic field generating device, a measuring container, a magnetic field regulating device and a remote observing system, wherein the measuring container is placed in the magnetic field generating device, the magnetic field generating device comprises an upper support, a lower support, a first electromagnet and a second electromagnet, the upper support and the lower support are fixed through four screws matched with nuts, the first electromagnet is placed in the hollow portion of the upper support, the second electromagnet is placed in the hollow portion of the lower support, the same magnetic poles of the first electromagnet and the second electromagnet are opposite, the first electromagnet and the second electromagnet are connected in parallel and then connected with the magnetic field regulating device in series, and the remote observing system comprises a camera and a computer. According to the magnetic susceptibility measuring device based on magneto-Archimedes levitation, magnetic induction intensity can be effectively controlled through the magnetic field regulating device, and then a wider magnetic susceptibility measurement range is realized; the distance between the two electromagnets can be adjusted as needed during measurement, measuring span is enlarged, and the flexibility of the device is improved greatly.

Description

A kind of magnetic susceptibility measurement device and method suspending based on magnetic Archimedes

Technical field

The invention belongs to field of measuring technique, be specifically related to a kind of magnetic susceptibility measurement device and method suspending based on magnetic Archimedes.

Background technology

Magnetic susceptibility is to describe the important physical amount of material magnetization character.According to the electron theory of the structure of matter, can prove that the magnetic susceptibility of material and its micromechanism have very close relationship.By measuring the magnetic susceptibility of these materials, can obtain many information of relevant their micromechanisms.Whether magnetic susceptibility exists the aspects such as unpaired electron and complex structure type to have important application in judging material molecule.By the mensuration of material magnetic susceptibility, calculating unpaired electrons in molecule is in research molecule, to become the effective ways of key situation.In environmental system, the secondary substance that the natural materials such as soil, rock, sediment, air borne dust and mankind's activity produce often shows different magnetic characteristics, they include the magnetic type of mineral, ferromagnetic crystal grain content with material, size forms and proportioning combination is relevant, have reflected to a certain extent the integrated informations such as its source matrix, build environment, handling process and deposition.Utilize material in environmental system difference and contact and the indicated Environment intension thereof on magnetic characteristic, can study environmental process, environmental activity and environmental problem under different time and space scales, and then disclose the historical and machine-processed of Environment Change.Magnetic susceptibility measurement instrument is in the mensuration of material electronic structure, the measurement of the magnetic response of the material that in environmental magnetism, the natural material such as soil, sediment and rock and mankind's activity produce in artificial magnetic field, the extraction of geology, geographical environment information, and the magnetic of magnetic fluid, the application in the fields such as the mensuration of stability and industrial gasses analysis have great significance.Therefore, magnetic susceptibility measurement instrument and equipment has caused showing great attention to of many scientific workers.

Present stage, the method for measurement of species magnetic susceptibility mainly contained: magnetic balance method and use the AC mutual induction method of electromagnetic principle.By magnetic balance method, measuring magnetic susceptibility is a kind of physical measurement method of routine, and at present, China there is no approved product, and it is that precise micro analytical balance, electromagnet and the direct supply of 0.1 milligram assembles voluntarily that applying unit adopts sensibility reciprocal mostly.According to the heterogeneity of determinand, magnetic balance method is divided into again Gouy method, Quincke method and Faraday method.The features such as Gouy method is applicable to measure the magnetic susceptibility of paramagnetic or diamagnetic substance, and it is simple that it has equipment, processing ease, but required sample size is large, precision is not good enough, is not suitable for and measures magnetic and superparamagnetism sample.Quincke method does not need the density of independent measurement sample, but it is only applicable to measure the magnetic susceptibility of liquids and gases, and required sample size is also very large.The temperature variant relation of magnetic susceptibility of above two kinds of equal inconvenient study samples of method.Faraday method experimental procedure is loaded down with trivial details, and operating process relative complex makes troubles to scientific research and engineering application.And AC mutual induction mensuration is mainly applicable to the measurement of metallic magnetic rate, specific aim is stronger, and measuring object is more single.Have in recent years people in succession to propose to carry out magnetic susceptibility measurement by new methods such as laser arrangement and the two spectrometer methods of NMR, yet these methods are relatively applicable to measuring the magnetic susceptibility of transition element ion compound, the scope of application is narrow.

Summary of the invention

The problem existing for prior art, the invention provides a kind of magnetic susceptibility measurement device and method suspending based on magnetic Archimedes.

Technical scheme of the present invention is:

The magnetic susceptibility measurement device suspending based on magnetic Archimedes, comprises field generator for magnetic, measuring vessel, magnetic field adjusting device and telemetry observation system;

Described measuring vessel is positioned in field generator for magnetic;

Described field generator for magnetic comprises upper bracket, lower carriage, the first electromagnet and the second electromagnet, upper bracket, lower carriage are the support of hollow, between upper bracket, lower carriage, by four screw rod attaching nuts, fix, the first electromagnet is placed on the middle vacancy of upper bracket, the second electromagnet is placed on the middle vacancy of lower carriage, and the magnetic pole of the same name of the first electromagnet, the second electromagnet is relative;

Described magnetic field adjusting device is connected with the first electromagnet and the second electromagnet after parallel connection;

Described telemetry observation system comprises picture pick-up device and computing machine, and picture pick-up device is placed in the environment at field generator for magnetic, measuring vessel place, and is connected with computing machine.

This device is placed in the adjustable environment of temperature.

Between described the first electromagnet and upper bracket, fix by two bolts respectively between the second electromagnet and lower carriage.

The magnetic induction density of the magnetic induction density of described the first electromagnet, the second electromagnet is all within the scope of 0.2～1.0T.

Described magnetic field adjusting device comprises slide rheostat and direct supply, one end of slide rheostat connects the first electromagnet and the second electromagnet after parallel connection, the other end of slide rheostat connects one end of direct supply, and the other end of direct supply connects the first electromagnet and the second electromagnet after parallel connection.

Described magnetic field adjusting device comprises AC power and transformer, one end of transformer connects the first electromagnet and the second electromagnet after parallel connection, the other end of transformer connects one end of AC power, and the other end of AC power connects the first electromagnet and the second electromagnet after parallel connection.

The material of described upper bracket, lower carriage, four screw rods is non-magnetic alloy material.

Described four screw rods are for regulating within the scope of 40～80mm the spacing of the first electromagnet and the second electromagnet.

Adopt the described magnetic susceptibility measurement device suspending based on magnetic Archimedes to carry out the method for magnetic susceptibility measurement, comprise the following steps:

Step 1: get certain density standard solution and inject in measuring vessel, make liquid level of solution height reach the more than 4/5 of measuring vessel overall height; In test substance, the graininess sample of cut-off footpath between 0.2～0.3mm, is immersed in graininess sample in standard solution completely, and guarantees that specimen surface is without bubble;

Step 2: measuring vessel is placed in the magnetic field space between the first electromagnet and the second electromagnet, the central axis of measuring vessel is overlapped with the axis of the vertical direction of the first electromagnet, the second electromagnet as far as possible, treat that graininess sample reaches stable suspersion;

Step 3: when the graininess sample in measuring vessel reaches stable suspersion, read the hoverheight h of graininess sample by picture pick-up device; If the graininess sample in measuring vessel cannot reach stable suspersion, regulate the spacing of the first electromagnet and the second electromagnet or the gear of adjustment slide rheostat, change the size of magnetic field intensity, repeating step 2, until graininess sample can reach stable suspersion state, by picture pick-up device, read height h now;

Step 4: carry out hoverheight h, graininess sample magnetic susceptibility χ to be measured _snumerical value conversion, obtain the magnitude of magnetic susceptibility of graininess sample;

Step 4.1: determine local gravity acceleration g;

Step 4.2: calculate the density p that obtains standard solution according to the volumetric molar concentration of the standard solution injecting _mmagnetic susceptibility χ with standard solution _m;

${\mathrm{\ρ}}_m=\frac{1000\mathrm{cM}}{a}---\left(1\right)$

In formula: c is the volumetric molar concentration of the standard solution of injection, and M is relative molecular mass, and a is solute mass percent;

${\mathrm{\χ}}_m=\frac{m_w{\mathrm{\χ}}_w+m_c{\mathrm{\χ}}_c}{m_w+m_c}---\left(2\right)$

In formula: χ _w, χ _mbe respectively the magnetic susceptibility of pure water and the magnetic susceptibility of standard solution, m _w, m _cbe respectively the quality of solute in the quality of pure water in standard solution and standard solution;

Step 4.3: by tabling look-up or calculating the exact value ρ of graininess sample density to be measured _s;

Step 4.4: the resistance of slide rheostat and gear while reaching stable suspersion according to graininess sample, determine two electromagnet surface induction intensity B ₀;

Step 4.5: calculate magnetic induction on two electromagnet center lines and distribute;

According to the density p of gravity acceleration g, standard solution _mwith electromagnet surface induction intensity B ₀, obtain two electromagnet magnetic induction density B on electromagnet axis in its 0～h altitude range _z, and then determine magnetic induction density B on the interior electromagnet of 0～h altitude range axis _zand the relation between hoverheight h;

In 0～H altitude range, magnetic induction density on electromagnet axis:

$B_z=\frac{B_r}{2}[\frac{H-h+L_m}{\sqrt{{(H-h+L_m)}^2+R^2}}-\frac{H-h}{\sqrt{{(H-h)}^2+R^2}}-\frac{h+L_m}{\sqrt{{(h+L_m)}^2+R^2}}+\frac{h}{\sqrt{h^2+R^2}}]---\left(3\right)$

In formula: the diameter that R is electromagnet, B _rfor the magnetic charge surface density of electromagnet, L _mfor electromagnet thickness, H is the distance between the first electromagnet and the second electromagnet;

Step 4.6: set up the hoverheight h of graininess sample and the magnetic susceptibility χ of graininess sample _sfuntcional relationship;

${\mathrm{\χ}}_s=\frac{({\mathrm{\ρ}}_s-{\mathrm{\ρ}}_m)g{\mathrm{\μ}}_0}{B_z+\frac{d{B}_z}{\mathrm{dh}}}+{\mathrm{\χ}}_m---\left(9\right)$

In formula, g is acceleration of gravity, μ ₀for Vacuum Magnetic rate;

Step 4.7: generate magnetic susceptibility-altitude curve, i.e. χ _s-h curve;

Step 4.8: according to magnetic induction density B on graininess specimen suspension height, electromagnet axis _zand magnetic susceptibility-altitude curve, obtain graininess sample magnetic susceptibility to be measured;

Step 5: the magnetic susceptibility χ that records gained graininess sample _s, magnetic susceptibility measurement finishes.

Beneficial effect:

Determining that under the condition of electromagnet magnetic induction density, spacing and standard solution, sample can be realized suspension in the short period of time, measuring accuracy is higher; Adopt electromagnet, by magnetic field intensity regulator, can effectively control the size of magnetic induction density, thereby obtain magnetic susceptibility measurement scope more widely; In measuring process, can regulate as required the distance between two electromagnet, expand measurement range, greatly increase the dirigibility of device; The little quality of apparatus of the present invention volume is light, is not only easy to carry, and easily protects inner accurate container, makes it can be because transportation exerts an influence to measuring accuracy, stable work in work; Can, simultaneously for measuring the measurement of solid material and some fluent material magnetic susceptibility, not need special regulating device, simple to operate; In addition, by regulating different temperature, this device can also be measured the magnitude of magnetic susceptibility under test substance different temperatures, takes measurement of an angle changeable.

Accompanying drawing explanation

Fig. 1 is the magnetic susceptibility measurement apparatus structure schematic diagram suspending based on magnetic Archimedes of the specific embodiment of the invention;

In figure, 1, upper bracket, 2, screw rod, 3, nut, 4, bolt, 5, measuring vessel, the 6, second electromagnet, 7, lower carriage, 8, computing machine, 9, connecting line, 10, picture pick-up device, 11-the first electromagnet;

Fig. 2 is the h-χ of the embodiment of the present invention _sdata-switching process flow diagram;

Fig. 3 is the method flow diagram of the magnetic susceptibility measurement suspending based on magnetic Archimedes of the specific embodiment of the invention.

Embodiment

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is elaborated.

As shown in Figure 1, the magnetic susceptibility measurement device suspending based on magnetic Archimedes, comprises field generator for magnetic, measuring vessel 5, magnetic field adjusting device and telemetry observation system;

Measuring vessel 5 is positioned in field generator for magnetic; Measuring vessel 5 is selected transparent cylindrical container, and its outside vertical direction indicates scale, so that observed data;

Field generator for magnetic comprises upper bracket 1, lower carriage 7, the first electromagnet 11 and the second electromagnet 6, upper bracket 1, lower carriage 7 are the support of hollow, between upper bracket 1, lower carriage 7, by four screw rods 2, coordinate 16 nuts 3 fixing, the first electromagnet 11 is placed on the middle vacancy of upper bracket 1, the second electromagnet 6 is placed on the middle vacancy of lower carriage 7, and the magnetic pole of the same name of the first electromagnet 11, the second electromagnet 6 is relative;

Magnetic field adjusting device is connected with the first electromagnet 11 and the second electromagnet 7 after parallel connection;

Telemetry observation system comprises picture pick-up device 10 and computing machine 8, and picture pick-up device 10 is placed in the environment at field generator for magnetic, measuring vessel 5 places, and is connected by connecting line 9 with computing machine 8.

The magnetic susceptibility measurement device suspending based on magnetic Archimedes of present embodiment is placed in the adjustable environment of temperature.

Fixing by two bolts 4 respectively between the first electromagnet 11 and upper bracket 7, between the second electromagnet 6 and lower carriage 7.

The magnetic induction density of the magnetic induction density of the first electromagnet 11, the second electromagnet 6 is all within the scope of 0.2～1.0T.

Magnetic field adjusting device comprises slide rheostat and direct supply, one end of slide rheostat connects the first electromagnet 11 and the second electromagnet 6 after parallel connection, the other end of slide rheostat connects one end of direct supply, and the other end of direct supply connects the first electromagnet 11 and the second electromagnet 6 after parallel connection.

Magnetic field adjusting device comprises AC power and transformer, one end of transformer connects the first electromagnet 11 and the second electromagnet 6 after parallel connection, the other end of transformer connects one end of AC power, and the other end of AC power connects the first electromagnet 11 and the second electromagnet 6 after parallel connection.

The material of upper bracket 1, lower carriage 7, four screw rods 2 is non-magnetic alloy material.

Four screw rods 2 are for regulating within the scope of 40～80mm the spacing of the first electromagnet 11 and the second electromagnet 6.

Telemetry observation system is placed in horizontal table top, and height is equal with graininess specimen suspension position.

Embodiment 1

In the present embodiment, the first electromagnet 11 and the second electromagnet 6 are all selected diameter 80mm, high 70mm, the DC electromagnet of surface suction 120N～290N, its surface induction intensity is 0.4T, owing to selecting electromagnet, need external magnetic field regulator, measuring vessel is selected diameter 10mm, the clear glass cylindrical chamber of high 45mm, injecting the standard solution of measuring vessel can observe by external picture pick-up device the suspension situation of the effect of sample and sample, picture pick-up device by image transmitting to record at any time on computing machine, image is carried out to data acquisition, the hoverheight of the tape measure graininess sample by measuring vessel.

Using the manganese chloride solution of known density and magnetic susceptibility, as paramagnetic medium, be standard solution, its density is 1.24g/cm ³, magnetic susceptibility is 1.41 * 10 ^-4.Getting density is 1.180g/cm ³silica gel is as graininess sample to be measured.

The magnetic susceptibility measurement device that employing suspends based on magnetic Archimedes carries out the method for magnetic susceptibility measurement, as shown in Figure 3, comprises the following steps:

Step 1: getting concentration is in the manganese chloride solution injection measuring vessel of 3.0mol/L, makes liquid level of solution height reach the more than 4/5 of measuring vessel overall height; In test substance, the graininess sample of cut-off footpath between 0.2～0.3mm, is immersed in graininess sample in standard solution completely, and guarantees that specimen surface is without bubble;

Step 2: measuring vessel is placed in the magnetic field space between the first electromagnet and the second electromagnet, the central axis of measuring vessel is overlapped with the axis of the vertical direction of the first electromagnet, the second electromagnet as far as possible, treat that graininess sample reaches stable suspersion;

Step 3: when the graininess sample in measuring vessel reaches stable suspersion, read the hoverheight h of graininess sample by picture pick-up device; If the graininess sample in measuring vessel cannot reach stable suspersion, regulate the spacing of the first electromagnet and the second electromagnet or the gear of adjustment slide rheostat, change the size of magnetic field intensity, repeating step 2, until graininess sample can reach stable suspersion state, by picture pick-up device, read height h=8.3mm now;

Step 4: carry out hoverheight h, graininess sample magnetic susceptibility χ to be measured _snumerical value conversion, obtain the magnitude of magnetic susceptibility of graininess sample, its flow process as shown in Figure 2;

Step 4.1: determine local gravity acceleration g;

Step 4.2: calculate the density p that obtains standard solution according to the volumetric molar concentration of the standard solution injecting _mmagnetic susceptibility χ with standard solution _m;

${\mathrm{\ρ}}_m=\frac{1000\mathrm{cM}}{a}---\left(1\right)$

In formula: c is the volumetric molar concentration of the standard solution of injection, and M is relative molecular mass, and a is solute mass percent;

${\mathrm{\χ}}_m=\frac{m_w{\mathrm{\χ}}_w+m_c{\mathrm{\χ}}_c}{m_w+m_c}---\left(2\right)$

In formula: χ _w, χ _mbe respectively the magnetic susceptibility of pure water and the magnetic susceptibility of standard solution, m _w, m _cbe respectively the quality of solute in the quality of pure water in standard solution and standard solution;

Step 4.3: by tabling look-up or calculating the exact value ρ of graininess sample to be measured (suspending medium) density _s;

Step 4.4: the resistance of slide rheostat and gear while reaching stable suspersion according to graininess sample, determine two electromagnet surface induction intensity B ₀;

Step 4.5: calculate magnetic induction on two electromagnet center lines and distribute;

According to the density p of gravity acceleration g, standard solution _mwith electromagnet surface induction intensity B ₀, obtain two electromagnet magnetic induction density B on electromagnet axis in its 0～h altitude range _z, and then determine magnetic induction density B on the interior electromagnet of 0～h altitude range axis _zand the relation between hoverheight h;

In 0～h altitude range, magnetic induction density on electromagnet axis:

$B_z=\frac{B_r}{2}[\frac{H-h+L_m}{\sqrt{{(H-h+L_m)}^2+R^2}}-\frac{H-h}{\sqrt{{(H-h)}^2+R^2}}-\frac{h+L_m}{\sqrt{{(h+L_m)}^2+R^2}}+\frac{h}{\sqrt{h^2+R^2}}]---\left(3\right)$

In formula: the diameter that R is electromagnet, B _rfor the magnetic charge surface density of electromagnet, L _mfor electromagnet thickness, H is the distance between the first electromagnet and the second electromagnet;

Step 4.6: set up the hoverheight h of graininess sample and the magnetic susceptibility χ of graininess sample _sfuntcional relationship;

${\mathrm{\χ}}_s=\frac{({\mathrm{\ρ}}_s-{\mathrm{\ρ}}_m)g{\mathrm{\μ}}_0}{B_z+\frac{d{B}_z}{\mathrm{dh}}}+{\mathrm{\χ}}_m---\left(9\right)$

In formula, g is acceleration of gravity, μ ₀for Vacuum Magnetic rate;

Under room temperature environment, in test substance, get the sample that volume is enough little (can think even density, stable in properties and can represent the physical property of test substance), be placed in the magnetic fluid (standard solution) under Actions of Gradient Magnetic Field, when sample is realized suspension in standard solution, test substance will be subject to four kinds of acting forces and reach balance, i.e. gravity G, the buoyancy F of standard solution to sample _f, the directed force F of magnetic field to sample _m, the directed force F of magnetic fluid to sample in nonuniform magnetic fields _s, be expressed as:

G+F _f+F _m+F _s+F _g+F _mag＝0 (4)

In formula: F _g=G+F _f, be making a concerted effort of gravity and buoyancy; F _mag=F _m+ F _sfor there being making a concerted effort of magnetic fields power generation.

Wherein: F _g=(ρ _s-ρ _m) Vg (5)

$F_{\mathrm{mag}}=\frac{({\mathrm{\χ}}_s-{\mathrm{\χ}}_m)}{{\mathrm{\μ}}_0}V(B\·\▿)B---\left(6\right)$

Have: $F_g+F_{\mathrm{mag}}=({\mathrm{\ρ}}_s-{\mathrm{\ρ}}_m)\mathrm{Vg}+\frac{({\mathrm{\χ}}_s-{\mathrm{\χ}}_m)}{{\mathrm{\μ}}_0}V(B\·\▿)B=0---\left(7\right)$

In formula: χ _sand χ _mthe magnetic susceptibility that represents respectively sample and standard solution; V(m ³) represent the volume of sample; G is local gravitational acceleration, has considered that graininess sample is subject to buoyancy ρ in medium herein _mthe impact of gV; ρ _sand ρ _mbe respectively the density of graininess sample and the density of standard solution; μ ₀for permeability of vacuum, size is 4 π * 10 ^-7(NA ^-2); for Laplacian,

$\▿=\frac{\∂B_x}{\∂x}+\frac{\∂B_y}{\∂y}+\frac{\∂B_z}{\∂z}---\left(8\right)$

Because of gravity acceleration g=(0,0 ,-g), be only present on z direction of principal axis, therefore only consider the balance on z direction of principal axis.By the known B of above several formulas _z, therefore, particle to be measured reaches the hoverheight of balance and the relation of its magnetic susceptibility can be expressed as:

$\frac{({\mathrm{\ρ}}_s-{\mathrm{\ρ}}_m)g{\mathrm{\μ}}_0}{{\mathrm{\χ}}_s-{\mathrm{\χ}}_m}=B_z\frac{d{B}_z}{\mathrm{dh}}$

Or write as ${\mathrm{\χ}}_s=\frac{({\mathrm{\ρ}}_s-{\mathrm{\ρ}}_m)g{\mathrm{\μ}}_0}{B_z+\frac{d{B}_z}{\mathrm{dh}}}+{\mathrm{\χ}}_m---\left(9\right)$

To analyze known, solve above formula calculate loaded down with trivial details, workload is large.Therefore, utilize (the χ of magnetic susceptibility-highly _s-h) curve carries out function to formula (9) and solves under the prerequisite of given basic parameter, and basic parameter comprises: gravity acceleration g, Vacuum Magnetic rate μ ₀, the volumetric molar concentration m of standard solution, magnet surface magnetic induction density B ₀;

Step 4.7: generate magnetic susceptibility-altitude curve, i.e. χ _s-h curve;

Step 4.8: according to magnetic induction density B on graininess specimen suspension height, electromagnet axis _zand magnetic susceptibility-altitude curve, obtain graininess sample magnetic susceptibility to be measured;

In the situation that not requiring accurate density value, also can be similar at χ _son-h curve, directly compare reading, by measuring hoverheight, solve sample magnetic susceptibility χ _s.

In conjunction with formula (3) and formula (9), can try to achieve the accurate magnetic susceptibility of institute's test specimens.The magnetic susceptibility that calculates sample is-4.8 * 10 ^-6.

Step 5: the magnetic susceptibility χ that records gained graininess sample _s, magnetic susceptibility measurement finishes.

The relative error of measured value and standard value is 0.42%, and measuring accuracy is higher, and this device and method can be realized measurement function and meet and measure requirement.

Embodiment 2

The magnetic susceptibility measurement device of the present embodiment is identical with embodiment 1.

The present embodiment is using the manganese chloride solution of known density and magnetic susceptibility as paramagnetic medium and standard solution, and its density is 1.27g/cm ³, magnetic susceptibility is 1.45 * 10 ^-4, getting density is 2.230g/cm ³silicon dioxide be test substance.

Using selected manganese chloride solution as paramagnetic medium, inject measuring vessel, again graininess sample is placed in to paramagnetic medium (standard solution), measuring vessel is placed in the magnetic field space between two electromagnet, makes electromagnet and measuring vessel on coaxial vertical direction.

Adopt the above-mentioned magnetic susceptibility measurement device suspending based on magnetic Archimedes to carry out the method for magnetic susceptibility measurement, as shown in Figure 3, comprise the following steps:

Step 1: getting concentration is in the manganese chloride solution injection measuring vessel of 2.5mol/L, makes liquid level of solution height reach the more than 4/5 of measuring vessel overall height; In test substance, the graininess sample of cut-off footpath between 0.2～0.3mm, is immersed in graininess sample in standard solution completely, and guarantees that specimen surface is without bubble;

Step 2: measuring vessel is placed in the magnetic field space between the first electromagnet and the second electromagnet, the central axis of measuring vessel is overlapped with the axis of the vertical direction of the first electromagnet, the second electromagnet as far as possible, treat that graininess sample reaches stable suspersion;

Step 3: when the graininess sample in measuring vessel reaches stable suspersion, read the hoverheight h of graininess sample by picture pick-up device; If the graininess sample in measuring vessel cannot reach stable suspersion, regulate the spacing of the first electromagnet and the second electromagnet or the gear of adjustment slide rheostat, change the size of magnetic field intensity, making electromagnet surface induction intensity is 0.4T, repeating step 2, until graininess sample can reach stable suspersion state, by picture pick-up device, read height h=8.3mm now;

Step 4: carry out hoverheight h, graininess sample magnetic susceptibility χ to be measured _snumerical value conversion, obtain the magnitude of magnetic susceptibility of graininess sample, its flow process as shown in Figure 2;

Step 4.1: determine local gravity acceleration g;

Step 4.2: calculate the density p that obtains standard solution according to the volumetric molar concentration of the standard solution injecting _mmagnetic susceptibility χ with standard solution _m;

${\mathrm{\ρ}}_m=\frac{1000\mathrm{cM}}{a}---\left(1\right)$

In formula: c is the volumetric molar concentration of the standard solution of injection, and M is relative molecular mass, and a is solute mass percent;

${\mathrm{\χ}}_m=\frac{m_w{\mathrm{\χ}}_w+m_c{\mathrm{\χ}}_c}{m_w+m_c}---\left(2\right)$

In formula: χ _w, χ _mbe respectively the magnetic susceptibility of pure water and the magnetic susceptibility of standard solution, m _w, m _cbe respectively the quality of solute in the quality of pure water in standard solution and standard solution;

Step 4.3: by tabling look-up or calculating the exact value ρ of graininess sample to be measured (suspending medium) density _s;

Step 4.4: the resistance of slide rheostat and gear while reaching stable suspersion according to graininess sample, determine two electromagnet surface induction intensity B ₀;

Step 4.5: calculate magnetic induction on two electromagnet center lines and distribute;

According to the density p of gravity acceleration g, standard solution _mwith electromagnet surface induction intensity B ₀, obtain two electromagnet magnetic induction density B on electromagnet axis in its 0～h altitude range _z, and then determine magnetic induction density B on the interior electromagnet of 0～h altitude range axis _zand the relation between hoverheight h;

In 0～h altitude range, magnetic induction density on electromagnet axis:

$B_z=\frac{B_r}{2}[\frac{H-h+L_m}{\sqrt{{(H-h+L_m)}^2+R^2}}-\frac{H-h}{\sqrt{{(H-h)}^2+R^2}}-\frac{h+L_m}{\sqrt{{(h+L_m)}^2+R^2}}+\frac{h}{\sqrt{h^2+R^2}}]---\left(3\right)$

In formula: the diameter that R is electromagnet, B _rfor the magnetic charge surface density of electromagnet, L _mfor electromagnet thickness, H is the distance between the first electromagnet and the second electromagnet;

Step 4.6: set up the hoverheight h of graininess sample and the magnetic susceptibility χ of graininess sample _sfuntcional relationship;

${\mathrm{\χ}}_s=\frac{({\mathrm{\ρ}}_s-{\mathrm{\ρ}}_m)g{\mathrm{\μ}}_0}{B_z+\frac{d{B}_z}{\mathrm{dh}}}+{\mathrm{\χ}}_m---\left(9\right)$

In formula, g is acceleration of gravity, μ ₀for Vacuum Magnetic rate;

Step 4.7: generate magnetic susceptibility-altitude curve, i.e. χ _s-h curve;

Step 4.8: according to magnetic induction density B on graininess specimen suspension height, electromagnet axis _zand magnetic susceptibility-altitude curve, obtaining graininess sample magnetic susceptibility to be measured is-3.45 * 10 ^-6;

In the situation that not requiring accurate density value, also can be similar at χ _son-h curve, directly compare reading, by measuring hoverheight, solve sample magnetic susceptibility χ _s.

In conjunction with formula (3) and formula (9), can try to achieve the accurate magnetic susceptibility of institute's test specimens.The magnetic susceptibility that calculates sample is-4.8 * 10 ^-6.

Step 5: the magnetic susceptibility χ that records gained graininess sample _s, magnetic susceptibility measurement finishes.

The relative error of measured value and mark value is 0.45%, and measuring accuracy is higher, meets and measures requirement.

Embodiment 3

The magnetic susceptibility measurement device of the present embodiment is identical with embodiment 1.

Using the manganese chloride solution of known density and magnetic susceptibility, as paramagnetic medium, be standard solution, its density is 1.10g/cm ³, magnetic susceptibility is 1.25 * 10 ^-4.Getting density is 1.050g/cm ³polystyrene is graininess sample to be measured.

Experiment condition and experimental implementation are with embodiment 2, regulate size of current, making electromagnet surface induction intensity is 0.4T, and the hoverheight that the graduated scale by measuring vessel can obtain graininess sample to be measured is 7.6mm, according to the magnetic susceptibility χ that calculates graininess sample to be measured _sfor-2.78 * 10 ^-6.Measured value and standard value error are 0.48%, and measuring accuracy is higher, meet and measure requirement.

Embodiment 4

The magnetic susceptibility measurement device of the present embodiment is identical with embodiment 1.

Using the manganese chloride solution of known density and magnetic susceptibility, as paramagnetic medium, be standard solution, its density is 1.10g/cm ³, magnetic susceptibility is 1.25 * 10 ^-4.Getting density is 1.030g/cm ³the aluminium block of 1 * 1 * 1mm be graininess sample to be measured.

Using selected manganese chloride solution as paramagnetic medium, inject suspension chamber, with dropper by sample grain blobs in paramagnetism medium, experiment condition and experimental implementation are with embodiment 2, regulate size of current, making electromagnet surface induction intensity is 0.4T, the hoverheight that graduated scale by measuring vessel can obtain graininess sample to be measured is 5.2mm, according to the magnetic susceptibility that calculates particle to be measured, is 1.73 * 10 ^-6.Measured value and standard value error are 0.49%, and measuring accuracy is higher, meet and measure requirement.

Claims (9)

1. the magnetic susceptibility measurement device suspending based on magnetic Archimedes, is characterized in that: comprise field generator for magnetic, measuring vessel, magnetic field adjusting device and telemetry observation system;

Described measuring vessel is positioned in field generator for magnetic;

Described field generator for magnetic comprises upper bracket, lower carriage, the first electromagnet and the second electromagnet, upper bracket, lower carriage are the support of hollow, between upper bracket, lower carriage, by four screw rod attaching nuts, fix, the first electromagnet is placed on the middle vacancy of upper bracket, the second electromagnet is placed on the middle vacancy of lower carriage, and the magnetic pole of the same name of the first electromagnet, the second electromagnet is relative;

Described magnetic field adjusting device is connected with the first electromagnet and the second electromagnet after parallel connection;

Described telemetry observation system comprises picture pick-up device and computing machine, and picture pick-up device is placed in the environment at field generator for magnetic, measuring vessel place, and is connected with computing machine.

2. the magnetic susceptibility measurement device suspending based on magnetic Archimedes according to claim 1, is characterized in that: this device is placed in the adjustable environment of temperature.

3. the magnetic susceptibility measurement device suspending based on magnetic Archimedes according to claim 1, is characterized in that: between described the first electromagnet and upper bracket, fix by two bolts respectively between the second electromagnet and lower carriage.

4. the magnetic susceptibility measurement device suspending based on magnetic Archimedes according to claim 1, is characterized in that: the magnetic induction density of the magnetic induction density of described the first electromagnet, the second electromagnet is all within the scope of 0.2～1.0T.

5. the magnetic susceptibility measurement device suspending based on magnetic Archimedes according to claim 1, it is characterized in that: described magnetic field adjusting device comprises slide rheostat and direct supply, one end of slide rheostat connects the first electromagnet and the second electromagnet after parallel connection, the other end of slide rheostat connects one end of direct supply, and the other end of direct supply connects the first electromagnet and the second electromagnet after parallel connection.

6. the magnetic susceptibility measurement device suspending based on magnetic Archimedes according to claim 1, it is characterized in that: described magnetic field adjusting device comprises AC power and transformer, one end of transformer connects the first electromagnet and the second electromagnet after parallel connection, the other end of transformer connects one end of AC power, and the other end of AC power connects the first electromagnet and the second electromagnet after parallel connection.

7. the magnetic susceptibility measurement device suspending based on magnetic Archimedes according to claim 1, is characterized in that: the material of described upper bracket, lower carriage, four screw rods is non-magnetic alloy material.

8. the magnetic susceptibility measurement device suspending based on magnetic Archimedes according to claim 1, is characterized in that: described four screw rods are for regulating within the scope of 40～80mm the spacing of the first electromagnet and the second electromagnet.

9. adopt the magnetic susceptibility measurement device suspending based on magnetic Archimedes claimed in claim 1 to carry out the method for magnetic susceptibility measurement, it is characterized in that: comprise the following steps:

Step 1: get certain density standard solution and inject in measuring vessel, make liquid level of solution height reach the more than 4/5 of measuring vessel overall height; In test substance, the graininess sample of cut-off footpath between 0.2～0.3mm, is immersed in graininess sample in standard solution completely, and guarantees that specimen surface is without bubble;

Step 2: measuring vessel is placed in the magnetic field space between the first electromagnet and the second electromagnet, the central axis of measuring vessel is overlapped with the axis of the vertical direction of the first electromagnet, the second electromagnet as far as possible, treat that graininess sample reaches stable suspersion;

Step 3: when the graininess sample in measuring vessel reaches stable suspersion, read the hoverheight h of graininess sample by picture pick-up device; If the graininess sample in measuring vessel cannot reach stable suspersion, regulate the spacing of the first electromagnet and the second electromagnet or the gear of adjustment slide rheostat, change the size of magnetic field intensity, repeating step 2, until graininess sample can reach stable suspersion state, by picture pick-up device, read height h now;

Step 4: carry out hoverheight h, graininess sample magnetic susceptibility χ to be measured _snumerical value conversion, obtain the magnitude of magnetic susceptibility of graininess sample;

Step 4.1: determine local gravity acceleration g;

Step 4.2: calculate the density p that obtains standard solution according to the volumetric molar concentration of the standard solution injecting _mmagnetic susceptibility χ with standard solution _m;

${\mathrm{\ρ}}_m=\frac{1000\mathrm{cM}}{a}---\left(1\right)$

In formula: c is the volumetric molar concentration of the standard solution of injection, and M is relative molecular mass, and a is solute mass percent;

${\mathrm{\χ}}_m=\frac{m_w{\mathrm{\χ}}_w+m_c{\mathrm{\χ}}_c}{m_w+m_c}---\left(2\right)$

In formula: χ _w, χ _mbe respectively the magnetic susceptibility of pure water and the magnetic susceptibility of standard solution, m _w, m _cbe respectively the quality of solute in the quality of pure water in standard solution and standard solution;

Step 4.3: by tabling look-up or calculating the exact value ρ of graininess sample density to be measured _s;

Step 4.4: the resistance of slide rheostat and gear while reaching stable suspersion according to graininess sample, determine two electromagnet surface induction intensity B ₀;

Step 4.5: calculate magnetic induction on two electromagnet center lines and distribute;

According to the density p of gravity acceleration g, standard solution _mwith electromagnet surface induction intensity B ₀, obtain two electromagnet magnetic induction density B on electromagnet axis in its 0～h altitude range _z, and then determine magnetic induction density B on the interior electromagnet of 0～h altitude range axis _zand the relation between hoverheight h;

In 0～h altitude range, magnetic induction density on electromagnet axis:

$B_z=\frac{B_r}{2}[\frac{H-h+L_m}{\sqrt{{(H-h+L_m)}^2+R^2}}-\frac{H-h}{\sqrt{{(H-h)}^2+R^2}}-\frac{h+L_m}{\sqrt{{(h+L_m)}^2+R^2}}+\frac{h}{\sqrt{h^2+R^2}}]---\left(3\right)$

In formula: the diameter that R is electromagnet, B _rfor the magnetic charge surface density of electromagnet, L _mfor electromagnet thickness, H is the distance between the first electromagnet and the second electromagnet;

Step 4.6: set up the hoverheight h of graininess sample and the magnetic susceptibility χ of graininess sample _sfuntcional relationship;

${\mathrm{\χ}}_s=\frac{({\mathrm{\ρ}}_s-{\mathrm{\ρ}}_m)g{\mathrm{\μ}}_0}{B_z+\frac{d{B}_z}{\mathrm{dh}}}+{\mathrm{\χ}}_m---\left(9\right)$

In formula, g is acceleration of gravity, μ ₀for Vacuum Magnetic rate;

Step 4.7: generate magnetic susceptibility-altitude curve, i.e. χ _s-h curve;

Step 4.8: according to magnetic induction density B on graininess specimen suspension height, electromagnet axis _zand magnetic susceptibility-altitude curve, obtain graininess sample magnetic susceptibility to be measured;

Step 5: the magnetic susceptibility χ that records gained graininess sample _s, magnetic susceptibility measurement finishes.