A sealing device and sealing method for a high-speed solid-state nuclear magnetic resonance rotor.

Abstract

This invention provides a sealing device and method for a high-speed solid-state NMR rotor. The sealing device includes a first structure, a second structure, a precision needle gauge, a first base, a second base, a sleeve, a sample, a sample loading tool guide rod, a rotor drive cap, and a manual precision vise. The sealing method utilizes a sealing gasket of appropriate thickness, pressed against the inner wall of the rotor by centrifugal force at high speed, sealing the gap between the bottom cap / drive cap at both ends of the rotor and the inner wall of the rotor, thereby preventing external air from contacting the sample powder. This invention significantly improves the stability of the sample during sampling and enables the acquisition of high-resolution solid-state NMR spectra at high speeds. The developed sealing tool can be used in conjunction with the rotor's sample loading tool in the inert atmosphere of a glove box, achieving the processing and sealing of solid-state NMR samples in one step. The method is simple to operate, highly practical, and suitable for various dehydrated samples and solid samples sensitive to water / oxygen / air.

Description

Technical Field

[0001] This invention relates to the field of sealing technology, and more particularly to a sealing device and sealing method for a high-speed solid nuclear magnetic resonance rotor. Background Technology

[0002] Solid-state nuclear magnetic resonance (NMR) is a characterization technique that studies solid samples, primarily used for the qualitative or quantitative analysis of sparingly soluble substances or compounds whose structure changes after dissolution. Unlike high-resolution liquid NMR spectroscopy, solid-state NMR peaks broaden due to chemical shift anisotropy (CSA) and dipole / quadrupole coupling, severely affecting the resolution of solid-state NMR spectra. To obtain high-resolution spectra in solid-state NMR detection, magic-angle spinning (MAS) is often employed. This involves high-speed rotation of the sample along an axis at a specific angle (54.74°) to the main magnetic field, averaging out most of the anisotropic spin interactions that contribute to peak broadening. The rotor, a crucial component of the MAS system, carries the high-speed rotation of the solid sample and is widely used in various solid-state NMR experiments. Its rotational speed limit depends primarily on the rotor's material and dimensions. To ensure the strength of the MAS rotor, zirconia, known for its high hardness, is used. Conventional MAS rotors generally come in two forms: straight-through and semi-through. Straight-through rotors are easier to manufacture and facilitate sample replacement and cleaning, but both ends require caps, increasing complexity. Semi-through rotors offer advantages such as simpler structure, larger sample loading capacity, and better overall rotor integrity, but they are more complex to manufacture and less prone to cleaning residual sample, thus they are often used for large-diameter rotors. Currently, the most commonly used rotor model is the 3.2mm outer diameter rotor, with a speed range of 0–24kHz. There are also conventional 4mm MAS rotors with a speed range of 0–14kHz. Generally, as the rotor outer diameter decreases and the magic angle rotation speed increases, the resolution of the NMR spectrum also increases. With the development and application of ultra-high-speed magic angle rotating probes, commercially available 0.7mm MAS probes can currently reach speeds up to 110kHz.

[0003] In the periodic table, hydrogen nuclei have nearly 100% natural abundance and a high magnetogyrality, making them the most sensitive and widely used elemental magnetic resonance (NMR) detectors. Given the atomic resolution of solid-state NMR, it is particularly advantageous for studying short-range ordered structural materials like molecular sieves, and it allows for non-destructive testing. Therefore, solid-state NMR has become a powerful tool for studying the acidity characteristics and active site chemical structures of solid acid catalysts such as molecular sieves. Furthermore, the high field strength and high rotational speed further enhance the resolution of proton NMR spectroscopy, which is a significant advantage for structural studies.

[0004] Solid samples that are highly sensitive to water vapor or oxygen, such as dehydrated and activated molecular sieves, undergo rapid changes in their structural properties upon exposure to air under unsealed conditions, leading to… 1 H, 27 Significant changes in NMR spectra such as Al severely interfere with sample structure characterization and quantitative analysis. Therefore, before performing solid-state NMR experiments, samples are typically transferred to a glove box, placed in a well-sealed solid-state NMR rotor under an inert atmosphere, and then NMR signals are acquired under anhydrous and oxygen-free conditions. Regarding rotor sealing techniques, the main methods reported in the literature are:

[0005] 1. Preparation of small ampoules using the heat-sealing method: Solid samples are pre-loaded into small glass tubes and evacuated, followed by pretreatment such as adsorption and reaction. After pretreatment, one end of the glass tube is placed in liquid nitrogen, and the other end is melted and sealed with a flame. The sealed ampoule is then inserted into an NMR tube. Considering that solid-state NMR experiments often require high-speed rotation (>10kHz), the strength of the ampoule, the shape after sealing, and the uniformity of the sample powder inside the ampoule are crucial. The experiment carries the risk of ampoule breakage and is difficult to replicate.

[0006] 2. After vacuum dehydration of the powder sample in a standard reaction tube / dehydration tube, it is transferred to a glove box under sealed conditions and then loaded into a solid-state NMR rotor under an inert atmosphere. The sealing degree of this method depends on the structural design and material properties of the solid-state NMR rotor. Currently, Bruker rotors with an outer diameter ≥3.2 mm, using Kel-F material caps, can achieve good sealing under medium-to-low speed (≤24 kHz) testing conditions. However, for molecular sieves / oxides with complex hydrogen signals, the resolution of the proton spectra acquired at medium-to-low speeds is often limited due to the strong dipole coupling in the system, thus restricting structural characterization. The more efficient 1H-1H homonuclear decoupling capability at high speeds (≥40 kHz) can significantly improve the resolution of the proton spectra of molecular sieves / oxides. However, rotors with an outer diameter ≤1.9 mm used at high speeds are open at both ends, and the caps are all made of Vespel material, which cannot achieve effective sealing, making it difficult for dehydrated molecular sieves / oxides sensitive to water or oxygen to remain stable during testing.

[0007] 3. In 2020, Dr. Kui-Zhi Chen and his colleagues at the High Magnetic Field Laboratory in the United States collaborated with the Jeffery L. White laboratory at Oklahoma State University, employing a method to improve sealing: adding finely ground elemental sulfur powder between the sample and the drive cap inside the NMR rotor to prevent the sample from contacting water vapor or oxygen. However, actual testing showed that this sealing method only works for Pheonix rotors with an outer diameter of 3.2 mm, and not for Bruker rotors with an outer diameter ≤1.9 mm. Furthermore, sulfur powder is a flammable and explosive substance; it is prone to explosion or combustion when mixed with air, so it must be stored in a dark, sealed, and carefully handled environment. In addition, from a toxicological perspective, sulfur powder is classified as a low-toxicity hazardous material. Long-term excessive exposure to sulfur dust may cause skin allergies and permanent eye damage, while long-term inhalation may cause pathological reactions. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a sealing device and method for a high-speed rotor used in solid-state NMR spectroscopy. The invention primarily utilizes a sealing gasket of appropriate thickness, pressed tightly against the inner wall of the rotor by centrifugal force at high speed, sealing the gaps between the bottom caps / drive caps at both ends of the rotor and the inner wall, thereby preventing external air from contacting the sample powder. For dehydrated oxides and water- and oxygen-sensitive materials such as molecular sieves, this technology significantly improves sample stability during sampling and enables the acquisition of high-resolution solid-state NMR spectra at high speeds. The developed sealing tool can be used in conjunction with the rotor's sample loading tool in the inert atmosphere of a glove box, achieving one-step processing and sealing of solid-state NMR samples. The method is simple to operate, highly practical, and suitable for various dehydrated samples and solid samples sensitive to water, oxygen, and air.

[0009] The technical means employed in this invention are as follows:

[0010] A sealing device for a high-speed rotor of solid nuclear magnetic resonance, comprising: a first structure, a second structure, a first base, a second base, a sleeve, a sample, a rotor drive cap, and a manual precision vise;

[0011] The first structure includes a first rotor body with openings at both ends, a bottom sealing gasket, and a rotor bottom cap. The rotor bottom cap is fastened to the bottom of the first rotor body, and the bottom sealing gasket is installed at the bottom inside the first rotor body. The sample is inserted into the first rotor body and is tightly fitted above the bottom sealing gasket.

[0012] The second structure includes a second rotor body with openings at both ends and a top sealing gasket. The second rotor body is placed on the first base, and the top sealing gasket is installed at the bottom inside the second rotor body.

[0013] The first rotor body and the second rotor body have the same structural dimensions;

[0014] The sleeve is placed on the second base. The first structure is inserted into the bottom of the sleeve, and the second structure is inserted into the sleeve and contacts the top of the first rotor body. The top sealing gasket inside the second rotor body is squeezed into the first rotor body and tightly fitted to the sample by a manual precision bench vise. The rotor drive cap is used to fasten to the top of the first rotor body, which contains the rotor bottom cap, bottom sealing gasket, sample and top sealing gasket, to achieve sealing of the sample in the rotor.

[0015] Furthermore, it also includes a precision needle gauge, which is used to insert into the first rotor body to compact the bottom sealing gasket and to insert into the second rotor body to compact the top sealing gasket.

[0016] Furthermore, the precision needle gauge is made of tungsten steel, and its outer diameter is 0.01 to 0.05 mm smaller than the inner diameter of each rotor body.

[0017] Furthermore, it also includes a sample loading tool guide rod, which is used to insert into the first rotor body to compact the sample and make it fit tightly against the bottom sealing gasket.

[0018] Furthermore, both the bottom and top sealing gaskets are made of a sealing material, which is a mixture of polytetrafluoroethylene powder and molybdenum disulfide powder, wherein the mass fraction of molybdenum disulfide is 8%.

[0019] Furthermore, the manual precision flat-jaw pliers are made of 20CrMnTi, with a jaw width of 63mm, a jaw height of 32mm, a body height of 63mm, a maximum opening of 85mm, and a body length of 190mm.

[0020] Furthermore, both the base and the sleeve are made of polytetrafluoroethylene.

[0021] Furthermore, the inner diameter of the sleeve is 0.02 to 0.04 mm larger than the outer diameter of each rotor body, and the height of the sleeve is the sum of the lengths of the two rotor bodies.

[0022] The present invention also provides a sealing method for a sealing device for a high-speed rotor of solid nuclear magnetic resonance, including a bottom sealing gasket preparation and sample loading process, a top sealing gasket preparation process, and a top sealing gasket transfer process.

[0023] The preparation and loading process of the bottom sealing gasket includes the following steps:

[0024] S11. Using the sample loading tool that comes with the rotor, fasten the bottom of the first rotor body with the rotor bottom cap to the two open ends;

[0025] S13. Heat the sealing material, namely PTFE material mixed with 8% molybdenum disulfide, at 120 degrees Celsius for two hours on a vacuum line to remove trace amounts of water vapor adsorbed from the air.

[0026] S13. Fill the first rotor body with the prepared sealant, covering the bottom of the first rotor body.

[0027] S14. Use a precision needle gauge with a diameter smaller than the inner diameter of the first rotor body to compact the sealing material at the bottom of the first rotor body; remove the precision needle gauge, at which point a bottom sealing gasket is formed at the bottom of the rotor.

[0028] S15. Using a manual precision bench vise, crank its handle to fix the first structure as a whole, and further use a precision pin gauge to press the bottom sealing gasket at the bottom of the first rotor body firmly.

[0029] S16. Using the matching rotor sample loading tool, load the powder sample into the first rotor body, and use the sample loading tool guide rod to compact the sample; during this process, a large amount of powder sample overflows and sticks to the inner wall of the first rotor body;

[0030] The preparation process of the top sealing gasket includes the following steps:

[0031] S21. Take another second rotor body with openings at both ends and place the second rotor body on a smooth base.

[0032] S22. Fill the second rotor body with an appropriate amount of prepared sealing material, at a moderate height, covering the bottom of the second rotor body.

[0033] S23. Insert a precision needle gauge with a diameter smaller than the inner diameter of the second rotor body, press down firmly to compress the sealing material and form a top sealing gasket 5.

[0034] S24. Using a manual precision bench vise, crank its handle to fix the second structure as a whole, and further use a precision pin gauge to press the top sealing gasket 5 at the bottom of the second rotor body.

[0035] The transfer process of the top sealing gasket includes the following steps:

[0036] S31. Place the sleeve on a smooth base;

[0037] S32. Insert the first rotor body containing the powder sample and the bottom sealing gasket and with the bottom cap fastened into the bottom of the sleeve and place it below. At this time, you can see that there are a lot of sample powder stuck on the inner wall of the first rotor body.

[0038] S33. The prepared top sealing gasket, together with the second rotor body, is put into the sleeve and placed on top. The sleeve contains two rotor bodies placed one above the other.

[0039] S34. Using a precision needle gauge with a diameter smaller than the inner diameter of the rotor body, push the top sealing gasket from the second rotor body to the first rotor body from top to bottom. At the same time, all the powder sample on the inner wall of the first rotor body can be pushed clean and compacted.

[0040] S35. Using a manual precision bench vise, crank its handle and use a precision needle gauge to further squeeze and push the top sealing gasket in the first rotor body to make it fit tightly against the sample, sealing the gap between the rotor bottom cap / rotor drive cap at both ends of the first rotor body and the inner wall of the first rotor body, blocking the contact between external air and sample powder.

[0041] S36. Using the sample loading tool that comes with the rotor, place the rotor drive cap on top of the first rotor body. The sample loading and sealing can be completed in one go, and the sample can then be transferred to the nuclear magnetic resonance instrument for detection.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] 1. The technology of this invention can be used in conjunction with the sample loading tool of the rotor in the inert atmosphere of the glove box, so as to realize the processing and sealing of solid nuclear magnetic resonance samples sensitive to water / oxygen / air in one step.

[0044] 2. The sealing method of this invention is simple to operate, easy to control, and highly practical. It is suitable for sealing various solid samples that are highly sensitive to water vapor or oxygen in the rotor and can be widely used in the nuclear magnetic resonance characterization of solid materials.

[0045] 3. The sealing material used in this invention is a mixture of polytetrafluoroethylene (PTFE) and molybdenum disulfide, which does not contain a hydrogen background. Both materials have excellent lubricating properties. First, PTFE has high lubricity, possessing the lowest coefficient of friction among solid materials, and also exhibits non-adhesion, having the lowest surface tension among solid materials, but it has low hardness. Molybdenum disulfide also has good dispersibility and non-adhesion properties, as well as good lubrication properties, but its coefficient of friction is not low enough. This invention mixes the two together, specifically by incorporating 8-10% by mass of molybdenum disulfide into PTFE, modifying pure PTFE and significantly increasing the hardness of the sealing material.

[0046] 4. The present invention introduces a manual precision flat-jaw pliers, which can further compress the bottom / top sealing gasket, increase its mechanical strength, and at the same time seal the gap between the bottom cap / drive cap at both ends of the rotor and the inner wall of the rotor, so that the sealing effect is better.

[0047] 5. The sealing method of this invention makes cleaning the small rotor after use much easier, greatly reducing damage to the rotor drive cap. For example, a traditional 1.3mm rotor needs to rotate at high speed under magic angle conditions during NMR testing. Powder samples are thrown between the inner wall of the rotor and the drive cap, making it very difficult to remove the drive cap after the test, resulting in significant wear and tear on the drive cap. The gasket seal in the sealing method of this invention also provides excellent lubrication, making it easier to remove the drive cap and greatly extending the service life of the rotor and its matching drive cap.

[0048] 6. The technology of this invention is simple to operate and easy to use. The developed sealing method can achieve a good sealing effect on rotors with an outer diameter ≤1.9mm used at high speeds (≥40kHz).

[0049] For the reasons stated above, this invention can be widely applied in fields such as sealing. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram illustrating the preparation of the bottom sealing gasket of the present invention.

[0052] Figure 2 This is a schematic diagram illustrating the preparation of the top sealing gasket of the present invention.

[0053] Figure 3 This is a schematic diagram of the transfer of the top sealing gasket according to the present invention.

[0054] Figure 4 This is a schematic diagram of the manual precision bench vise used in the rotor sealing method of the present invention.

[0055] Figure 5 This is a schematic diagram of the rotor sealing process operation of the present invention.

[0056] Figure 6 Solid-state nuclear magnetic resonance (NMR) measurements of ZSM-5 molecular sieve samples sealed at an ultra-high rotation speed of 50 kHz for different durations, as described in this embodiment of the invention. 1 H spectrum.

[0057] In the figure: 1. Precision needle gauge; 2. Rotor body; 3. Bottom sealing gasket; 4. Rotor bottom cap; 5. Top sealing gasket; 6. Base; 7. Sleeve; 8. Sample; 9. Sample loading tool guide rod; 10. Rotor drive cap. Detailed Implementation

[0058] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0061] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0062] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0063] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0064] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0065] This invention addresses the problem of achieving highly efficient sealing of a high-speed solid-state NMR (NMR) MAS rotor (outer diameter ≤ 1.9 mm), characterized by simple operation, easy process control, and reusability. The rotor sealing material is primarily low-porosity, easily shaped, and self-lubricating polytetrafluoroethylene (PTFE) powder, with a small amount (8-10 wt%) of molybdenum disulfide powder added. Combined with a developed sealing method, including an internally formed sealing gasket and an externally formed top sealing gasket, highly efficient sealing of the NMR MAS rotor is achieved. The core of this technology is that a sealing gasket of appropriate thickness is pressed against the inner wall of the rotor by centrifugal force at high speed, sealing the gap between the bottom cap / drive cap at both ends of the rotor and the inner wall, thereby preventing external air from contacting the sample powder. For water- and oxygen-sensitive materials such as dehydrated oxides and molecular sieves, this technology significantly improves sample stability during sampling and enables the acquisition of high-resolution solid-state NMR spectra at high speeds. The developed sealing tool can be used in conjunction with the rotor's sample loading tool in the inert atmosphere of a glove box, enabling the processing and sealing of solid NMR samples to be completed in one step. The method is simple to operate, highly practical, and suitable for various dehydrated samples and solid samples sensitive to water / oxygen / air.

[0066] This invention discloses a sealing device for a high-speed rotor in solid-state nuclear magnetic resonance imaging (NMR), comprising: a first structure, a second structure, a precision needle gauge 1, a first base 6, a second base 6, a sleeve 7, a sample 8, a sample loading tool guide rod 9, a rotor drive cap 10, and a manual precision bench vise. The first structure includes a first rotor body 2 with openings at both ends, a bottom sealing gasket 3, and a rotor bottom cap 4. The second structure includes a second rotor body 2 with openings at both ends and a top sealing gasket 5.

[0067] The present invention discloses a sealing method for a high-speed rotor used in solid-state nuclear magnetic resonance research, comprising a bottom sealing gasket 3 preparation and sample loading process, a top sealing gasket 5 preparation process, and a top sealing gasket 5 transfer process.

[0068] The preparation process of the bottom sealing gasket 3 involves a rotor body 2 with openings at both ends, a rotor bottom cap 4, a precision pin gauge 1 with a diameter slightly smaller than the inner diameter of the rotor body 2, and manual precision flat-jaw pliers. The sealing material is a mixture of polytetrafluoroethylene (PTFE) powder and molybdenum disulfide powder, wherein the mass fraction of molybdenum disulfide is 8%. The addition of molybdenum disulfide can improve the mechanical strength of PTFE powder after compression. The outer diameter of the tungsten carbide precision pin gauge 1 used is 0.01-0.05 mm smaller than the inner diameter of the rotor body 2, and it is thoroughly cleaned to remove oil before use. The manual precision flat-jaw pliers further compress the bottom sealing gasket 3, which can increase the mechanical strength of the sealing gasket and seal the gap between the rotor bottom cap 4 and the inner wall of the rotor body 2.

[0069] The preparation process of the top sealing gasket 5 involves a rotor body 2 with openings at both ends, a precision pin gauge 1 with a diameter slightly smaller than the inner diameter of the rotor body 2, a PTFE base 6, and manual precision flat-jaw pliers. The sealing material is also a mixture of PTFE and molybdenum disulfide, with a molybdenum disulfide mass fraction of 8%, possessing certain deformability and mechanical strength. The outer diameter of the tungsten carbide precision pin gauge 1 is 0.01–0.05 mm smaller than the inner diameter of the rotor body 2, and it is thoroughly cleaned to remove oil before use. The manual precision flat-jaw pliers are commercially available, made of 20CrMnTi, with a jaw width of 63 mm, a jaw height of 32 mm, a plier body height of 63 mm, a maximum opening of 85 mm, and a plier body length of 190 mm. The manual precision flat-jaw pliers further compress the top sealing gasket 5 to increase its mechanical strength.

[0070] The transfer process of the top sealing gasket 5 involves a PTFE sleeve 7, a PTFE base 6, two rotors, the top sealing gasket 5, and a precision pin gauge 1 with a diameter slightly smaller than the inner diameter of the rotor body 2, along with manual precision flat-nose pliers. The inner diameter of the sleeve 7 is 0.02–0.04 mm larger than the outer diameter of the rotor body 2, and the height of the sleeve 7 is the sum of the lengths of the two rotor bodies 2. There are two rotor bodies 2. The first rotor body 2 contains the prepared top sealing gasket 5, and the second rotor body 2 contains the rotor bottom cap 4, the bottom sealing gasket 3, and the assembled sample 8. The outer diameter of the tungsten carbide precision pin gauge 1 is 0.01–0.05 mm smaller than the inner diameter of the rotor body 2, and it is thoroughly cleaned to remove oil before use.

[0071] Example 1

[0072] This invention discloses a sealing method for a high-speed rotor used in solid-state NMR research. It can be used in conjunction with a dehydrated and activated sample 8 under an inert atmosphere in a glove box, enabling the processing and sealing of water / oxygen / air-sensitive solid-state NMR samples to be completed in one step. The sealing method comprises several parts: the preparation and sample loading process of the bottom sealing gasket 3, the preparation process of the top sealing gasket 5, and the transfer process of the top sealing gasket 5.

[0073] like Figure 1 As shown, the specific implementation steps for the preparation of the bottom sealing gasket 3 and the sample loading process are as follows:

[0074] (1) Using the commercial sample-setting tool that comes with the rotor (using existing tools), fasten the bottom of the rotor body 2 to the rotor bottom cap 4;

[0075] (2) The preferred sealing material, namely PTFE material with 8% molybdenum disulfide, is heated at 120 degrees Celsius for two hours on a vacuum line to remove the trace amount of water vapor adsorbed in the air.

[0076] (3) Fill the prepared sealing material into the rotor body 2, using an appropriate amount, and cover the bottom of the rotor body 2.

[0077] (4) Use a precision needle gauge 1 with a diameter slightly smaller than the inner diameter of the rotor body 2 to compact the sealing material at the bottom of the rotor body 2;

[0078] (5) Using a manual precision vise, crank the handle to... Figure 1 The entire assembly is then fixed in place, and the sealing gasket at the bottom of the rotor body 2 is further pressed firmly using the precision needle gauge 1.

[0079] (6) Remove the precision needle gauge 1. At this point, a bottom sealing gasket 3 has been formed at the bottom of the rotor. Using the Bruker rotor sample loading tool, load the powder sample 8 into the rotor body 2, and use the sample guide rod 9 of the loading tool to compact the sample 8. During this process, a large amount of powder sample 8 will overflow and stick to the inner wall of the rotor body 2.

[0080] The above are the specific implementation steps for the preparation and sample loading of the bottom sealing gasket 3, which are... Figure 5 The rotor sealing process is shown in area A of the flowchart.

[0081] Next, the specific implementation steps of the preparation process of the top sealing gasket 5 will be introduced, such as... Figure 2 As shown:

[0082] (1) Take another new rotor body 2 with open ends (i.e., the second rotor body 2) and place it on a smooth polytetrafluoroethylene base 6.

[0083] (2) Fill the prepared sealing material into the rotor body 2 with an appropriate amount and height, and cover the bottom of the rotor body 2.

[0084] (3) Insert a precision needle gauge 1 with a diameter slightly smaller than the inner diameter of the rotor body 2, press it down firmly, squeeze the sealing material to form a top sealing gasket 5, and then remove the precision needle gauge 1.

[0085] (4) Using a manual precision vise, crank the handle to... Figure 2 The entire assembly is then fixed in place, and the top sealing gasket (top sealing gasket 5) at the bottom of the rotor body 2 is further pressed firmly using the precision needle gauge 1.

[0086] The gasket prepared in this way has significantly improved mechanical strength compared to pure PTFE material. The preparation of the top sealing gasket 5 described above is... Figure 5 The process flow chart for the rotor sealing operation is shown in area B.

[0087] The transfer process of the rotor top seal 5, such as Figure 3As shown, the design of sleeve 7 plays a crucial role in the transfer of the sealing gasket. The inner diameter of sleeve 7 is 0.02–0.04 mm larger than the outer diameter of rotor body 2, ensuring no misalignment when rotor body 2 is placed inside sleeve 7. The specific implementation steps are as follows:

[0088] (1) Place the self-designed polytetrafluoroethylene sleeve 7 on a smooth polytetrafluoroethylene base 6;

[0089] (2) The rotor body 2 containing the powder sample 8 and the bottom sealing gasket 3 and the bottom cap 4 is put into the bottom of the sleeve 7 and placed below. At this time, it can be seen that there are many powder samples 8 stuck on the inner wall of the rotor body 2.

[0090] (3) Figure 2 The prepared top sealing gasket 5, together with the rotor body 2, is inserted into the sleeve 7 and placed on top. The sleeve 7 contains two rotor bodies 2 placed one above the other.

[0091] (4) Using a precision needle gauge 1 with a diameter slightly smaller than the inner diameter of the rotor body 2, push the top sealing gasket 5 from the upper rotor body 2 to the lower rotor body 2 from top to bottom. This step can clean up all the powder sample 8 on the inner wall of the rotor body 2 and compact it.

[0092] (5) Using a manual precision bench vise, crank the handle and further use the precision needle gauge 1 to squeeze the top sealing gasket 5 of the rotor body 2 to make it fit tightly with the sample 8, sealing the gap between the rotor bottom cap 4 / rotor drive cap 10 at both ends of the rotor body 2 and the inner wall of the rotor body 2, blocking the contact between external air and the powder of the sample 8.

[0093] (6) Using the commercial sample loading tool that comes with the rotor, the rotor drive cap 10 is placed on top of the rotor body 2 below, and the sample loading and sealing are completed in one go, and it can be transferred to the nuclear magnetic resonance instrument for detection.

[0094] Implementation example:

[0095] The sealing method of the system described in this invention is highly advantageous for NMR studies of solid materials that are very sensitive to water vapor. Combined with a small-sized, high-speed MAS rotor in high-field, high-speed experiments on an 800M NMR spectrometer, the resolution of the proton NMR spectrum is further improved. The sealed powder sample significantly extends the time available for NMR spectrum acquisition, allowing the sample to remain stable for a longer period. For example, ZSM-5 molecular sieve samples that have undergone hydrothermal treatment under mild conditions, after being sealed, exhibit solid-state NMR results at a high speed of 50kHz for different durations. 1 The H spectrum yielded abundant acidic information about the ZSM-5 molecular sieve.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sealing device for a high-speed solid-state nuclear magnetic resonance rotor, characterized in that, include: First structure, second structure, first base (6), second base (6), sleeve (7), sample (8), rotor drive cap (10) and manual precision bench vise; The first structure includes a first rotor body (2) with openings at both ends, a bottom sealing gasket (3) and a rotor bottom cap (4). The rotor bottom cap (4) is fastened to the bottom of the first rotor body (2), and the bottom sealing gasket (3) is laid on the bottom of the first rotor body (2). The sample (8) is inserted into the first rotor body (2) and closely adheres to the top of the bottom sealing gasket (3). The second structure includes a second rotor body (2) with openings at both ends and a top sealing gasket (5). The second rotor body (2) is placed on the first base (6), and the top sealing gasket (5) is installed at the bottom inside the second rotor body (2). The first rotor body (2) and the second rotor body (2) have the same structural dimensions; The sleeve (7) is placed on the second base (6). The first structure is inserted into the bottom of the sleeve (7). The second structure is inserted into the sleeve (7) and contacts the top of the first rotor body (2). The top sealing gasket (5) inside the second rotor body (2) is squeezed into the first rotor body (2) and tightly fitted with the sample (8) by a manual precision bench vise. The rotor drive cap (10) is used to fasten the top of the first rotor body (2) which contains the rotor bottom cap (4), bottom sealing gasket (3), sample (8) and top sealing gasket (5) to achieve sealing of the sample in the rotor. It also includes a precision needle gauge (1), which is used to insert into the first rotor body (2) to compact the bottom sealing gasket (3) and to insert into the second rotor body (2) to compact the top sealing gasket (5).

2. The sealing device for a high-speed solid-state nuclear magnetic resonance rotor according to claim 1, characterized in that, The precision needle gauge (1) is made of tungsten steel and its outer diameter is 0.01 ~ 0.05 mm smaller than the inner diameter of each rotor body (2).

3. The sealing device for a high-speed solid-state nuclear magnetic resonance rotor according to claim 1, characterized in that, It also includes a sample loading tool guide rod (9), which is used to insert into the first rotor body (2) to compact the sample (8) and fit it tightly against the bottom sealing gasket (3).

4. The sealing device for a high-speed solid-state nuclear magnetic resonance rotor according to claim 1, characterized in that, Both the bottom sealing gasket (3) and the top sealing gasket (5) are made of sealing material, which is a mixture of polytetrafluoroethylene powder and molybdenum disulfide powder, wherein the mass fraction of molybdenum disulfide is 8%.

5. The sealing device for a high-speed solid-state nuclear magnetic resonance rotor according to claim 1, characterized in that, The manual precision bench vise is made of 20CrMnTi, with a jaw width of 63 mm, a jaw height of 32 mm, a body height of 63 mm, a maximum opening of 85 mm, and a body length of 190 mm.

6. The sealing device for a high-speed solid-state nuclear magnetic resonance rotor according to claim 1, characterized in that, The base (6) and sleeve (7) are both made of polytetrafluoroethylene.

7. The sealing device for a high-speed solid-state nuclear magnetic resonance rotor according to claim 1 or 6, characterized in that, The inner diameter of the sleeve (7) is 0.02 ~ 0.04 mm larger than the outer diameter of each rotor body (2), and the height of the sleeve (7) is the sum of the lengths of the two rotor bodies (2).

8. A sealing method for a sealing device for a high-speed solid-state nuclear magnetic resonance rotor as described in any one of claims 1-7, characterized in that, This includes the preparation and loading process of the bottom sealing gasket (3), the preparation process of the top sealing gasket (5), and the transfer process of the top sealing gasket (5); The preparation and loading process of the bottom sealing gasket (3) includes the following steps: S11. Using the sample loading tool that comes with the rotor, fasten the bottom of the first rotor body (2) with the rotor bottom cap (4) with the openings at both ends. S13. Heat the sealing material, namely PTFE material mixed with 8% molybdenum disulfide, at 120 degrees Celsius for two hours on a vacuum line to remove trace amounts of water vapor adsorbed in the air. S13. Put the prepared sealing material into the first rotor body (2) and cover the bottom of the first rotor body (2); S14. Use a precision needle gauge (1) with a diameter smaller than the inner diameter of the first rotor body (2) to compact the sealing material at the bottom of the first rotor body (2); remove the precision needle gauge (1), at which point a bottom sealing gasket (3) is formed at the bottom of the rotor. S15. Using a manual precision bench vise, crank its handle to fix the first structure as a whole, and further use a precision needle gauge (1) to press the bottom sealing gasket (3) at the bottom of the first rotor body (2). S16. Using the matching rotor sample loading tool, load the powder sample (8) into the first rotor body (2), and use the sample loading tool guide rod (9) to compact the sample (8); during this process, a large amount of powder sample (8) overflows and sticks to the inner wall of the first rotor body (2); The preparation process of the top sealing gasket (5) includes the following steps: S21. Take another second rotor body (2) with openings at both ends and place the second rotor body (2) on a smooth base (6); S22. Put the prepared sealing material into the second rotor body (2) at a moderate height, covering the bottom of the second rotor body (2); S23. Insert a precision needle gauge (1) with a diameter smaller than the inner diameter of the second rotor body (2), press down forcefully to compress the sealing material to form a top sealing gasket (5). S24. Using a manual precision bench vise, crank its handle to fix the second structure as a whole, and further use a precision needle gauge (1) to press the top sealing gasket (5) at the bottom of the second rotor body (2). The transfer process of the top sealing gasket (5) includes the following steps: S31. Place the sleeve (7) on a smooth base (6); S32. The first rotor body (2) containing the powder sample (8) and the bottom sealing gasket (3) and the rotor bottom cap (4) is inserted into the bottom of the sleeve (7) and placed below. At this time, it can be seen that a lot of sample (8) powder is stuck on the inner wall of the first rotor body (2). S33. The prepared top sealing gasket (5) together with the second rotor body (2) is put into the sleeve (7) and placed on top. The sleeve (7) contains two rotor bodies (2) placed one above the other. S34. Using a precision needle gauge (1) with a diameter smaller than the inner diameter of the rotor body (2), push the top sealing gasket (5) from the second rotor body (2) into the first rotor body (2) from top to bottom. At the same time, all the powder sample (8) on the inner wall of the first rotor body (2) can be pushed clean and compacted. S35. Using a manual precision bench vise, crank its handle and use the precision needle gauge (1) to further squeeze the top sealing gasket (5) pushed into the first rotor body (2) so that it fits tightly against the sample (8), sealing the gap between the rotor bottom cap (4) and rotor drive cap (10) at both ends of the first rotor body (2) and the inner wall of the first rotor body (2), thus blocking the contact between external air and the sample (8) powder. S36. Using the sample loading tool that comes with the rotor, put the rotor drive cap (10) on top of the first rotor body (2). The sample loading and sealing can be completed in one go, and it can be transferred to the nuclear magnetic resonance instrument for detection.

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