Magnetic force booster, strong magnetic force field generator, crystal and its manufacturing method

Abstract

To provide a magnetic force booster that can easily create a pseudo-zero gravity environment, a strong magnetic force field generator, a crystal, and a manufacturing method thereof.SOLUTION: A magnetic force booster that locally strengthens the magnetic force includes a magnetic material with a truncated cone shape, a cylindrical shape, or a combination of the truncated cone portion and the cylindrical portion, and one bottom surface of the magnetic material is an opening, and the other bottom surface is an opening or has a doughnut-shaped disc.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a magnetic force booster, a strong magnetic force field generator, a crystal, and a method for producing the same. [Background technology]

[0002] When crystallizing substances such as proteins, the crystals grow in close contact with the wall of the container, and the difference in the crystal structure between the surface in contact with the wall and the surface not in contact with the wall poses a problem in crystal structure analysis.

[0003] In crystal structure analysis, precipitated crystals are picked up using a small ring-shaped nylon tool called a loop and placed on the sample stage at a synchrotron radiation facility, but this work often relies on the experience and intuition of the worker, and there is a high risk of damaging or distorting the crystal. If a crystal grows attached to the container wall, it is extremely difficult to remove it, so the technology to grow crystals without contact is a common challenge for all crystals.

[0004] When crystals grow stably in a floating state in a solution without contacting the container, isotropic or highly symmetric crystals can be obtained, but crystals grown under such completely containerless conditions have not yet been obtained.

[0005] In Patent Document 1, a strong magnetic force field is generated by arranging a disk-shaped ferromagnetic body symmetrically about the central axis above the equatorial plane inside the hollow interior of a solenoid-shaped superconducting magnet, and arranging a ring-shaped ferromagnetic body symmetrically about the central axis above the disk-shaped ferromagnetic body without contacting the disk-shaped ferromagnetic body.However, with such a device, it is extremely difficult to stably magnetically levitate non-magnetic bodies. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3532888 Summary of the Invention [Problem to be solved by the invention]

[0007] A main object of the present invention is to provide a technology that can easily realize a pseudo-zero gravity environment. [Means for solving the problem]

[0008] The present invention provides a magnetic force booster, a strong magnetic force field generator, a crystal, and a method for manufacturing the same. [1] A magnetic force booster that locally strengthens a magnetic force, characterized in that the magnetic force booster includes a magnetic body that is shaped like a truncated cone, a cylinder, or a combination of a truncated cone and a cylinder, and one bottom surface of the magnetic body is an opening, and the other bottom surface is an opening or has a donut-shaped disk. [2] The magnetic force booster according to [1], comprising a truncated cone-shaped magnetic body. [3] The magnetic force booster according to [1] or [2], wherein the magnetic material is iron. [4] The magnetic force booster according to any one of [1] to [3], wherein the thickness of the magnetic body in the shape of a truncated cone, a cylinder, or a combination of a truncated cone and a cylinder is 0.1 to 0.5 mm. [5] The magnetic force booster according to any one of [1] to [4], which is disposed inside a superconducting magnet. [6] A strong magnetic force field generator, comprising: a magnetic force booster according to any one of [1] to [4] disposed inside a superconducting magnet; and a radial component of the magnetic force in the magnetic force booster directed toward the center. [7] A method for producing crystals, characterized in that in the apparatus described in [6], a container containing a solution of a diamagnetic crystalline substance is placed inside the magnetic force booster, and the crystals are grown without coming into contact with the walls of the container. [8] A crystal of a diamagnetic material that grows isotropically. [9] The crystal according to [8], which is a protein crystal. [Effects of the Invention]

[0009] The magnetic force booster of the present invention actively utilizes the "radial component of the magnetic force" to allow crystals to float and aggregate in one location in the solution, thereby achieving protein crystal growth under completely containerless conditions. Completely containerless conditions are conditions under which protein crystals can be floated in a protein solution without ever coming into contact with a container, achieving stable crystal growth. In the present invention, the use of a small magnetic force booster increased the spatial gradient of the magnetic force strength, enabling the crystals to be concentrated locally. By miniaturizing the booster, the support pillars that secure the booster can be simplified, while simultaneously improving safety, operability, and versatility. Furthermore, the volume of the booster of the present invention can be very small, reducing the risk of introduction into high-magnetic-field spaces. It is not necessary to install a counterpart magnetic body in a symmetrical position to maintain balance when secured, significantly reducing safety risks when used in high-magnetic-field spaces. If the magnetic force booster of the present invention is used as an accessory for superconducting magnets, its range of use will expand beyond crystal growth, contributing to the development of a wide range of academic fields, including engineering and applied physics. [Brief explanation of the drawings]

[0010] [Figure 1] Examples of the shape of the magnetic force booster of the present invention are shown below. (A) SUS430, (B) Ni, (C) SUS430 [Figure 2] 1 shows an example of the shape of the magnetic force booster of the present invention. [Figure 3] Distribution of the resultant force of gravity and magnetic force generated by the superconducting magnet. (A) Blue indicates a pseudo-weightless state. (B) Contour distribution of the radial magnetic force generated by the superconducting magnet. [Figure 4]This shows the resultant vector of magnetic and gravitational forces in the space above the ring-shaped magnetic force booster, calculated using three-dimensional numerical calculations. The resultant vector of the magnetic force vector B (▽·B) generated in the surrounding area and the gravitational vector is also shown. [Figure 5] 1 shows the magnetic force field when using a cylindrical magnetic force booster of the present invention. [Figure 6] 1 shows a magnetic force field generated by a disk-shaped component that constitutes the magnetic force booster described in Patent Document 1. [Figure 7] 1 shows a photograph of lysozyme crystals grown in a completely containerless state obtained in Example 1. [Figure 8] 1 shows a photograph of lysozyme crystals grown in a completely containerless state obtained in Example 2. [Figure 9] 1 shows a photograph of lysozyme crystals grown in a completely containerless state obtained in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] The shape of the magnetic force booster of the present invention can be a truncated cone, a cylinder, or a shape that combines a truncated cone and a cylinder, but a disk-shaped booster with circular openings on two bottom surfaces and no internal space or openings is not included in the present invention. Examples of the shape of the magnetic force booster of the present invention are shown in Figures 1 and 2.

[0012] The material constituting the magnetic force booster includes magnetic metals such as iron, cobalt, nickel, etc., and may be a metal alone or an alloy. The preferred material is iron or an alloy containing iron. Examples of alloys containing iron include stainless steel, such as austenitic stainless steels (SUS301, 301J1, 301L, 302, 302B, 303, 303Cu, 304, 304L, 304N1, 304N2, 304Cu, 304J1, 304J2, 305, 305J1, 309S, 310S, 312, 315J1, 315J2, 316, 316L, 316N, 316J1, 316LN, 316J1L, 317, 317J1, 317J1, 317L, 347, 630, 631, 836L, 890L, XM15J1, XM7, etc.), ferritic SUS (SUS430, 405, 410L, 429, 430F, 430LX, 434, 434J1L, 436L, 443J1, 444, 445J1, 445J2, 447J1, XM27, SUH409, SUH409L, etc.), martensitic SUS (SUS403, 410, 410S, 410F2, 416, 420J1, 420J2, 420F, 420F2, 431, 440A, 440B, 440C, 440F, etc.), preferably ferritic SUS, more preferably SUS430. The magnetic force booster is magnetized by placing it inside a superconducting magnet.

[0013] For example, SUS430 is magnetized at 1.1 to 1.5 T. In the experiments of the present invention, the applied magnetic flux density was always 2.0 T or higher, so the magnetic force booster reached saturation magnetization.

[0014] When using a magnetic force booster made of SUS430 in a magnetic field, a support base that securely fixes it inside the bore is essential. Figures 2(A) and (B) both show examples of magnetic force boosters that have protrusions in the radial direction and are fixed by hooking metal fittings onto them.

[0015] The magnetic force booster of the present invention is inserted into a superconducting magnet for use. In this embodiment, it simultaneously controls both the magnetic force field formed by the superconducting magnet and the magnetic force field generated by magnetizing the magnetic force booster. The magnetic force field created by the superconducting magnet has a small spatial gradient of magnetic force strength due to the large coil dimensions, making it difficult to control in a small space. Therefore, the magnetic force field created by the superconducting magnet is used to stably levitate crystals in the vertical direction. On the other hand, the magnetic force field created by the booster has a large spatial gradient of magnetic force field due to the small size of the booster, allowing a strong localized radial magnetic force to be applied to the crystals. Furthermore, since it can be placed close to the crystallization vessel, it has the advantage of making it easy to control the levitation position of the crystals. In this way, the magnetic force booster of the present invention is used primarily to stabilize crystals in the radial direction.

[0016] Figure 3 shows the results of numerical calculations of the strength distribution of the resultant force vector when it is assumed that magnetic force and gravity cancel each other out near the coil edge of the superconducting magnet. The blue region in Figure 3(A) represents a pseudo-weightless state, and the yellow to red areas indicate that the resultant force vector becomes stronger. In order to stably levitate and aggregate the crystals in this region, it is necessary to install a magnetic force booster slightly below the blue position.

[0017] Figure 4 shows the resultant force vector of the magnetic force vector B(▽·B) and the gravity vector generated around the ring-shaped magnetic force booster, calculated using three-dimensional numerical calculations. The magnetic force booster has a diameter of 20 mm, a height of 4 mm, and wall thicknesses of 0.1, 0.2, 0.3, 0.5, 1.0, 3.0, and 5.0 mm under conditions (1) to (7), respectively. The magnetic force vector Fm(f r , f θ , f z ) vertical component f z In order to stably levitate a diamagnetic object at point A (pink circle in Figure 4(1)), the resultant force of the gravity vector G (0,0,-g) must be such that the force f z -g <0, vertically downward f z -g>0. Furthermore, in the radial direction, f r<0. Note that the radial component of the magnetic force, f r is always zero. In addition, since the magnetic force acts axially symmetrically, if the magnetic force booster is installed coaxially and rotationally symmetrically with the superconducting magnet, the circumferential component f θ is always zero.

[0018] As a result of the calculation, a distribution of lines of force was obtained that asymptotically stabilizes the diamagnetic material toward point A. The effect was significant when the thickness was 0.1 to 1.0 mm, but the effect of the magnetic force tended to weaken as the thickness increased. This is because the magnetic field gradient ▽·B became smaller as the magnetic field became more uniform. The thinner the thickness, the lighter the fixing hardware can be, improving safety and versatility. Based on the above findings, a magnetic force booster with a thinner thickness is desirable. The thickness of the magnetic force booster of the present invention is preferably 0.1 to 0.5 mm, more preferably 0.1 to 0.2 mm.

[0019] To achieve completely containerless conditions, the crystal must grow while maintaining a mechanically stable state. In other words, when the crystal descends vertically downward, a vertically upward force must act, and when it ascends vertically upward, a vertically downward force must act. Furthermore, when the crystal moves in the positive radial direction, a driving force must be generated in the opposite direction. Therefore, we will consider how to resolve the driving force acting on the crystal into the vertical and radial directions and achieve stability in each direction. Note that in a superconducting magnet, the magnetic force acts axially symmetrically, so the circumferential magnetic force component need not be taken into account.

[0020] Vertical stability can be easily achieved. Protein crystals are diamagnetic, so if they are grown above the coil of a superconducting magnet, the crystal will rise upward when the magnetic force is equal to (gravity of the crystal + buoyancy due to density difference acting on the crystal). The further the crystal is from the coil, the weaker the magnetic flux density is inversely proportional to the square of the distance, so the magnetic force also weakens rapidly. When the magnetic force is equal to (gravity of the crystal + buoyancy due to density difference acting on the crystal), the crystal will descend. Finally, the crystal will come to a stable rest at a position where (gravity of the crystal + buoyancy due to density difference acting on the crystal) = magnetic force. At this point, the crystal is in a pseudo-weightless state.

[0021] On the other hand, the radial magnetic force is not canceled out by gravity. Therefore, even a force so weak that it can be ignored under gravity becomes a driving force in a pseudo-weightless environment. Figure 5 shows the magnetic force distribution generated by a cylindrical component, calculated by numerical calculation. The distribution arrows indicate the direction of action on the diamagnetic protein crystals. Figure 5 shows that the magnetic force distribution is concentrated on the central axis at the bottom of the cylindrical component. This suggests that it has the effect of driving the diamagnetic protein crystals toward the central axis. Based on this result, the inventors conceived of a new magnetic force booster with a cylindrical shape. However, near the bottom of an actual cylindrical component, in addition to the magnetic force generated by the cylindrical component, the magnetic force generated by the superconducting magnet also acts, resulting in a combined force of these forces. Therefore, when using this magnetic force booster, the magnetic force distribution of the superconducting magnet must also be taken into consideration.

[0022] The magnetic force booster disclosed in Patent Document 1 features a cylindrical component and a disk-shaped component that are closely spaced and used as a single unit. The magnetic force distribution in this case is expressed by combining the magnetic force distribution generated by the cylindrical component (as shown in Figure 5) and the magnetic force field generated by the disk-shaped component. Figure 6 shows the magnetic force field generated by the disk-shaped component, calculated using three-dimensional numerical calculations. The distribution arrows indicate the direction of the magnetic force acting on the diamagnetic protein crystals. Figure 6 shows that the magnetic force is generated radially from the disk. This means that a region where the radial component of the magnetic force is negative does not exist in the space above the disk, and a driving force exists that expels the crystals from their central axis. As a result, even though the cylindrical component exerts the effect of driving the crystals toward their central axis, the presence of the disk-shaped component in the magnetic force booster almost completely cancels out the crystal aggregation effect as a whole. In other words, the magnetic force booster in Patent Document 1 is shaped to generate a uniform magnetic force field in the vertical direction. In contrast, the magnetic force booster of the present invention differs from the previous research in that it actively utilizes the radial magnetic force component to aggregate the crystals, and its purpose of use is also different from that of the previous research.

[0023] The configuration of the magnetic force booster of the present invention can effectively generate a radial component of magnetic force, and thus, when used in combination with a superconducting magnet, it can realize protein crystal growth under completely container-free conditions, which is one preferred embodiment of the present invention. By using the magnetic force booster of the present invention in combination with a superconducting magnet, crystals of diamagnetic substances other than proteins can also be produced under completely container-free conditions. Furthermore, by actively utilizing the "radial component of magnetic force" and increasing the spatial gradient of the magnetic force strength, the booster can be widely used in fields other than crystal growth.

[0024] By disposing the magnetic force booster of the present invention inside a superconducting magnet, a strong magnetic force field generator can be obtained. Any known superconducting magnet can be used.

[0025] By placing a magnetic force booster inside a strong magnetic force field generator and placing a container containing a solution of a diamagnetic crystalline material inside the magnetic force booster, and growing the crystals without contacting the container wall, it is possible to grow crystals under containerless conditions. Since these crystals grow without adhering to the crystallization container, they can be obtained as distortion-free crystals.

[0026] The crystal manufacturing method of the present invention utilizes the magnetic Archimedes effect to levitate crystals in a small magnetic field. This method uses a paramagnetic precipitant to make the entire solution of a diamagnetic substance such as a protein paramagnetic, and then crystals are grown while applying a magnetic force in this state. The solution is attracted to the stronger magnetic field, and this reciprocal force acts on the crystals of the diamagnetic substance such as a protein, making it possible to levitate the crystals even with a small magnetic force. The magnetic Archimedes effect also acts on the magnetic force generated by the magnetization of the booster, so it is effective in driving and agglomerating the crystals in the radial direction.

[0027] The crystals can be prepared by dissolving a magnetic adjuster (paramagnetic or diamagnetic substance) and a crystallizable diamagnetic substance in a solvent. This solution may further contain a solubilizer, dispersion stabilizer, suspension stabilizer, crystallization agent that promotes crystal precipitation, crystallization aid, etc.

[0028] Examples of the solvent include solvents having fluidity, such as water, alcohols (methanol, ethanol, propanol, butanol, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), amines (triethylamine, diethylamine, etc.), ethers (diethyl ether, tetrahydrofuran, isopropyl ether, etc.), esters (ethyl acetate, etc.), carboxylic acids (acetic acid, propionic acid, butanoic acid, pentanoic acid, etc.), aromatic hydrocarbons (benzene, toluene, xylene, etc.), halogenated hydrocarbons (chloroform, methylene chloride, etc.), acetonitrile, DMF, DMSO, acetamide, and other organic solvents.

[0029] Examples of paramagnetic substances added to a solvent as a magnetic modifier when the medium is water include gadolinium chloride, gadolinium nitrate, cobalt chloride, cobalt nitrate, nickel chloride, nickel nitrate, manganese chloride, manganese nitrate, and a contrast agent (gadolinium(III) dihydrogen diethylenetriaminepentaacetate hydrate (also known as gadopentetic acid)). The present inventors have successfully grown lysozyme crystals while magnetically levitating them using gadopentetic acid in combination with table salt (NaCl). As gadopentetic acid, for example, 97% gadolinium(III) dihydrogen diethylenetriaminepentaacetate hydrate manufactured by Sigma-Aldrich can be used.

[0030] When the medium is an organic solvent, examples of the paramagnetic substance to be added include organic acid salts and complex compounds containing gadolinium, cobalt, nickel, manganese, etc., which are soluble in the organic solvent.

[0031] Diamagnetic substances that can be added to a solvent as a magnetic adjuster include a wide range of organic substances that can be dissolved, dispersed, or suspended in the solvent, and various inorganic substances made of elements other than gadolinium, cobalt, nickel, and manganese. The amount of paramagnetic substance added to make a diamagnetic solvent paramagnetic varies depending on the strength of the paramagnetic properties. For example, if a gadolinium salt is used as the paramagnetic substance and water is used as the diamagnetic medium, a gadolinium concentration of 0.001 molar or higher will make the medium as a whole sufficiently paramagnetic to precipitate the diamagnetic substance.

[0032] The crystal of the present invention may be any diamagnetic substance, and includes a wide range of low-molecular-weight or high-molecular-weight organic and inorganic compounds, with preferred examples including proteins, organic semiconductor materials, and high-brightness semiconductor laser crystals. [Example]

[0033] The present invention will be described in more detail below with reference to examples. Example 1 The magnetic force booster shown in Figure 2(B) was used. The container was set so that the distance between the bottom of the container and the top of the magnetic force booster was 28 mm. Since the solution volume was approximately 1 mL, the solution depth was approximately 10 mm. Therefore, the combined forces of the vertical magnetic force, density difference buoyancy, and gravity were canceled out near the center of the solution at a position 28 + 5 = 33 mm vertically above the magnetic force booster. Finally, the top of the magnetic force booster was fixed at Z = +86 mm, and the crystallization experiment was performed with the center of the solution at Z = +119 mm.

[0034] The crystal growth process was photographed from the side, and the process of lysozyme crystals agglomerating into spherical shapes and growing in a completely container-free state was recorded using a cassette recorder. The footage was 65 minutes long, covering two tapes. We succeeded in capturing the crystal growth process in a completely container-free state in an extremely beautiful manner (Figure 7).

[0035] The crystallization conditions were 1.0030 g of water, 0.0798 g of lysozyme, 0.1510 g of gadolinium chloride hexahydrate, 0.0056 g of 1 M hydrochloric acid, a temperature of 17°C, and a magnetic field of 2.120 T (at Z=0).

[0036] Example 2 The magnetic force booster shown in Figure 2(B) was used. Since the purpose was to confirm reproducibility, the container position was exactly the same as in Example 1. The observation method was also the same. Lysozyme crystals grown in a completely container-free state were obtained as in Example 1, and it was confirmed that crystals grown in a completely container-free state can be obtained with good reproducibility by the crystal manufacturing method of the present invention (Figure 8).

[0037] The crystallization conditions were 1.0040 g of water, 0.0814 g of lysozyme, 0.1620 g of gadolinium chloride hexahydrate, and 0.00101 g of 1 M hydrochloric acid, at a temperature of 17°C and a magnetic field of 2.050 T (at Z=0).

[0038] Example 3 The magnetic force booster shown in Figure 2(A) was used. The container was set so that the distance between the bottom of the container and the top of the magnetic force booster was 30 mm. The experiment was performed with the center of the solution at Z = +119 mm, which means that the top of the magnetic force booster was at Z = +84 mm.

[0039] The crystal growth process was automatically photographed from the side every 10 minutes (using software called Image Pro Plus). Crystal growth in a completely container-free state was achieved (Figure 9). This suggests that the effect of the cylindrical part is more important than the "protrusion" part, which is the difference between the magnetic force boosters.

[0040] The crystallization conditions were 1.0012 g of water, 0.0827 g of lysozyme, 0.1432 g of gadolinium chloride hexahydrate, 0.0072 g of 1 M hydrochloric acid, a temperature of 22.0°C, and a magnetic field of 2.150 T (at Z=0).

Claims

1. A magnetic force booster that locally strengthens a magnetic force, the magnetic force booster including a magnetic body having a shape that combines a cylindrical portion and a donut-shaped disk portion, one bottom surface of the magnetic body being an opening and the other bottom surface being a donut-shaped disk portion, the cylindrical portion having a wall thickness of 0.1 to 1.0 mm.

2. A magnetic force booster as described in claim 1, wherein the cylindrical portion has a wall thickness of 0.1 to 0.5 mm.

3. 3. The magnetic force booster of claim 1 or 2, wherein the magnetic material is iron.

4. A magnetic force booster described in any one of claims 1 to 3, wherein the cylindrical portion has a wall thickness of 0.1 to 0.2 mm.

5. The magnetic force booster according to any one of claims 1 to 4, which is used by being disposed inside a superconducting magnet.

6. A strong magnetic force field generator, comprising: a magnetic force booster according to any one of claims 1 to 4 disposed inside a superconducting magnet; and a radial component of the magnetic force in the magnetic force booster directed toward the center.

7. 7. A method for producing crystals according to claim 6, characterized in that a container containing a solution of a diamagnetic crystalline material is placed inside a magnetic force booster, and the crystals are grown without contacting the walls of the container with the radial component of the magnetic force in the magnetic force booster facing toward the center.

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