阅读说明：本技术 一种用于透射电镜切片样品和切片转移装置的制备方法 (Preparation method for transmission electron microscope slicing sample and slicing transfer device ) 是由 张斌 赵晓伟 孙家豪 董天汭 王卓 陈曦 周小元 于 2019-10-15 设计创作，主要内容包括：本发明属于透射电子显微镜技术领域,公开了一种用于透射电镜切片样品和切片转移装置的制备方法,包括以下步骤：(1)样品头粗修；(2)精修；(3)切片前准备；(4)超薄切片(厚度通常小于50nm)；(5)样品转移至加热芯片加热区。本发明主要用于透射电镜超薄切片样品的制备,解决了透射电镜原位加热过程中样品定点转移至芯片加热区域困难的问题。(The invention belongs to the technical field of transmission electron microscopes, and discloses a preparation method for a transmission electron microscope slice sample and a slice transfer device, which comprises the following steps: (1) roughly trimming a sample head; (2) fine modification; (3) preparing before slicing; (4) ultra-thin sections (typically less than 50nm in thickness); (5) the sample was transferred to the heating chip heating zone. The method is mainly used for preparing the ultrathin slice sample of the transmission electron microscope, and solves the problem that the sample is difficult to be transferred to a chip heating area at a fixed point in the in-situ heating process of the transmission electron microscope.)

1. A preparation method for a transmission electron microscope ultrathin slice sample is characterized by comprising the following steps:

(1) roughly trimming, namely selecting a smooth bottom surface of the cylinder, respectively performing operations such as milling, grinding and polishing through a fine grinding all-in-one machine or a trimming machine to obtain a smooth plane, and controlling the feed amount when the peripheral plane is milled in the milling process to ensure that the length and the width of the top platform are smaller than 300 mu m;

(2) fine trimming, namely transferring the sample to an ultrathin slicer, performing fine trimming on the sample, assembling the trimming block, aligning a left blade with the middle point of the plane of the sample by using a self-made glass cutter, setting the thickness of each layer to be 300nm, setting the total feed to be about 150 mu m, starting automatic trimming, and trimming the block for multiple times to obtain a boss with a smooth surface;

(3) preparing before slicing, wherein a wet cutting method is adopted in the slicing process, a tool is set before slicing, water is filled into a water tank after the tool is set, and a liquid level can be lightly brushed by using a lash brush to ensure that the blade is in contact with the liquid level;

(4) and slicing, wherein the problems of rough surface of the sample head, idle cutting and the like can exist, the speed can be set to be 100mm/s, the slicing thickness is set to be 80nm, the surface of the sample is further trimmed, after the sample head is cut flatly and continuously and completely, the slicing thickness is not more than 50nm, the slicing speed is set to be 2mm/s, the actual slicing speed can be changed according to the sample condition, and automatic slicing is started.

(5) And (3) transferring the sliced sample, wherein the sliced sample needs to be transferred onto a heating chip after the ultrathin slicing is finished, and in order to provide a transfer success rate, a sample transfer device is recommended to assist the transfer of the sliced sample.

2. A preparation method for a transmission electron microscope slice transfer device is characterized by comprising the following steps:

(1) preparing and manufacturing a carrying bottom plate: selecting a sheet not less than 2cm multiplied by 2cm as a bottom plate, wherein the bottom plate material in the embodiment of the invention is a common laboratory glass slide, cleaning the bottom plate by absolute alcohol ultrasonic for 5 minutes, and airing for later use;

(2) preparing and manufacturing a limiting plate: taking a glass slide, preparing three silicon wafers with the thickness of about 3mm multiplied by 8mm, placing the materials in alcohol for ultrasonic treatment for 5 minutes, and airing for later use; placing a silicon wafer on a glass slide to form a groove shape, wherein the middle gap is about 5 mm;

(3) bonding and fixing of the limiting plate: the glass slide is placed on a heating plate and heated to 150 ℃, then paraffin is coated on the glass slide, after the glass slide is melted, a silicon wafer is placed, the position of the silicon wafer is adjusted, and then the temperature is reduced to enable the glass slide to be firmly bonded. Similarly, the bonding may be performed by using an AB glue.

3. The method for preparing a transmission electron microscope slice transfer device according to claim 2, characterized in that: the bottom plate in the step (1) is made of a bottom plate material which is a glass slide.

4. The method for preparing a transmission electron microscope slice transfer device according to claim 3, characterized in that: the heating temperature of the slide glass in the step (3) is 150 ℃.

5. The method for preparing the transmission electron microscope slice transfer device according to claim 4, wherein the method comprises the following steps: and (3) adopting paraffin or AB glue in the bonding process.

Technical Field

The invention relates to the technical field of in-situ heating research of transmission electron microscopes, in particular to a preparation method for a transmission electron microscope slice sample and a slice transfer device.

Background

The rapid development of the transmission electron microscope (hereinafter referred to as transmission electron microscope) technology makes the material structure research break through the atomic scale, and the latest spherical aberration correction imaging technology realizes the resolution of about 0.4 angstrom, so that the atomic scale structure research is one layer higher. In recent years, various in-situ technologies are introduced and developed, so that a transmission electron microscope is gradually developed into a powerful experimental platform (or called a nano laboratory) integrating microscopic research and micro-nano processing. The ideal experimental data always presupposes good quality samples. Transmission electron microscopy signals are based primarily on electrons penetrating the sample, thus requiring the sample to be sufficiently thin (typically less than 50nm or less). For this reason, various sample preparation techniques have been developed, and a sample preparation method using a bulk material as an example includes: conventional grinding-polishing combined ion thinning, mechanical stripping (cleaving), electrolytic double-spraying (metal material), focused ion beam cutting (FIB), ultra-thin slicing, and the like.

The in-situ heating research of the transmission electron microscope provides a basis for the research of the dynamic behavior change of the structure transformation under the condition of material temperature change, and further provides possibility for deeply exploring the relationship between the structure and the physical property of the material. At present, the transmission electron microscope in-situ heating is realized in two types: crucible heating and MEMS chip heating. The crucible type heating sample stage is simple in sample preparation and low in cost, is suitable for various transmission electron microscope samples, but is large in heating area, relatively poor in stability, incapable of accurately controlling the temperature of a material, and easy to cause obvious drift of the material, so that high-resolution imaging observation is difficult to realize. The MEMS chip heating has the advantages of small heating area, accurate temperature control, small sample drift, easy realization of observation of a high-resolution structure and realization of energy spectrum analysis at high temperature, but the sample preparation requirement is high and the experiment cost is high. There are two methods for conventional chip-based heated sample preparation: a dispersion-fishing method is adopted for powder samples, and the method is only suitable for nano powder materials with thickness suitable for electron microscope observation and the like; a FIB cutting-transferring method is usually adopted for a block sample, so that high-precision control and fixed-point transfer of the thickness, orientation and the like of the sample can be realized, the preparation cost of the sample is high, and the sample is often damaged (comprising surface amorphization, ion implantation and the like) due to the action of an ion beam. As a wide sample preparation method, the ultrathin section method has the characteristics of wide application range, large thin area, low cost, small damage and the like, but the fixed-point transfer of the sample is relatively difficult.

Disclosure of Invention

The invention aims to provide a preparation method for a transmission electron microscope slicing sample and a slicing transfer device, and solves the problem that the sample is difficult to transfer at a fixed point in the in-situ heating process of a transmission electron microscope.

1.The invention provides the basic scheme that: a method for preparing an ultra-thin (typically less than 50nm) section sample for transmission electron microscopy, comprising the steps of:

(1) roughly trimming, namely selecting a smooth bottom surface of the cylinder, respectively performing operations such as milling, grinding and polishing to obtain a smooth plane, and controlling the feed amount when the peripheral plane is milled in the milling process to ensure that the length and the width of the top platform are smaller than 300 mu m;

(2) fine trimming, namely transferring the sample to an ultrathin slicer, performing fine trimming on the sample, assembling the trimming block, aligning a left blade with the middle point of the plane of the sample by using a self-made glass cutter, setting the thickness of each layer to be 300nm, setting the total feed to be 150 mu m, starting automatic trimming, and trimming for multiple times to obtain a boss with a smooth surface;

(3) preparing before slicing, namely, adding a water tank on an assembled glass cutter in the slicing process to facilitate collection and transfer of sliced samples at the later stage, setting a tool before slicing, injecting water into the water tank after the tool setting is finished, and brushing the liquid level with a mascara brush to ensure that the tool edges are all contacted with the liquid level;

(4) automatic slicing, because there may be the surface roughness and the idle feed scheduling problem, can set up the speed as 100mm/s earlier, slice thickness sets up 80nm, carries out further trimming to the sample surface, and slice thickness is 50nm, begins automatic slicing.

(5) And (4) transferring a sliced sample, wherein the sliced sample needs to be transferred to a heating chip after the ultrathin slicing is finished. In order to provide a transfer success rate, a sample transfer device is suggested to assist the transfer of the sliced sample.

Further, the method can be used for preparing a novel materialAnd (2) the slicing speed in the step (1) is usually set to be 2-20mm/s, and the adjustment in a wider range can be carried out according to the actual situation of the sample.

A preparation method for a transmission electron microscope slice transfer device is characterized by comprising the following steps:

(1) preparing and manufacturing a carrying bottom plate: selecting a sheet not less than 2cm multiplied by 2cm as a bottom plate, wherein the bottom plate material in the embodiment of the invention is a common laboratory glass slide, cleaning the bottom plate by absolute alcohol ultrasonic for 5 minutes, and airing for later use;

(2) preparing and manufacturing a limiting plate: taking a glass slide, preparing three silicon wafers with the thickness of (3-4) × (6-8) mm, placing the materials in alcohol for ultrasonic treatment for 5 minutes, and airing for later use; placing the silicon chip on a glass slide to form a groove shape, wherein the middle gap is about 5mm (preferably slightly wider than the heating chip);

(3) bonding and fixing of the limiting plate: the glass slide is placed on a heating plate to be heated, then paraffin is coated on the glass slide, after the glass slide is melted, a silicon wafer is placed, and then the temperature is reduced to enable the glass slide to be firmly bonded.

Further, the method can be used for preparing a novel materialAnd (2) taking the bottom plate as a bottom plate material and a glass slide in the step (1).

Further, the method can be used for preparing a novel materialAnd (4) heating the glass slide at the temperature of about 150 ℃ in the step (3).

Further, the method can be used for preparing a novel materialAnd (3) adopting paraffin or AB glue in the bonding process.

Working principle of basic schemeAndthe beneficial effects are that:

(1) by using the scheme, the success rate and the accuracy of slice sample transfer are effectively improved, and the in-situ heating sample preparation and experiment are taken as a universal experiment method and have important reference significance for in-situ heating research of block samples, powder samples and the like;

(2) the inventor finds that in the process of research,the sample surface is too large and is easy to cause the wrinkles and the fragmentation of the slice, so the sample surface after rough trimming and fine trimming is smooth and preferably a rectangle or a right-angled trapezoid with the length and the width both less than 50 mu m (or less); according to the strength, hardness and plasticity of the sample material, a homemade glass knife or a diamond knife can be adopted in the process of trimming and slicing, but the diamond knife is relatively expensive. Due to SnSb₂Te₄The hardness is low, so a new glass cutter is adopted for slicing; the slicing speed in the slicing process depends on parameters such as hardness and slice thickness of a sample, and a thinner slice can be obtained by setting a higher speed. The phenomena of creasing, chattering mark, cracking and the like are easy to occur when slicing and sample preparation, so that the later experimental observation is influenced. Therefore, in the practical experiment, different slicing parameters are required to be set for different samples, and a flat and proper slice can be cut out through repeated exploration;

(3) the inventor finds that how to accurately transfer the prepared ultrathin slice to the specified position of the heating chip is another difficulty in-situ heating research in the research process; if there is a deviation, the sample will be wasted, and the environment around the chip will be polluted, and a lot of manpower and material resources will be consumed. Through a plurality of attempts, a simple and effective in-situ chip limiting and positioning device is researched for solving the problem, the device can effectively reduce the slippage of a chip in the sample transfer process in the actual use process, and the transfer accuracy is improved.

Drawings

FIG. 1 is a diagram of a sample rod, a heating chip and the like heated in situ by a transmission electron microscope according to the present invention.

FIG. 2 is a schematic diagram of a position-limiting and positioning device and a sample transfer according to the present invention.

Fig. 3 is a diagram of a sample preparation and transfer process provided by an embodiment of the present invention, including: effect image of ultrathin section, sample transfer effect image.

FIG. 4 shows an embodiment of the present invention, which provides SnSb₂Te₄Transmission electron microscope normal position heating image of ultra-thin section sample includes: the appearance and the component of the ultrathin section sample are respectively represented by high-resolution images of the same region at normal temperature (about 25 ℃), 100 ℃, 200 ℃ and 300 ℃.

Detailed Description

The following is further detailed by the embodiments in conjunction with fig. 1, fig. 2, fig. 3 and fig. 4:

reference numerals: 1: positioning a window; 2. fishing out a sample ring; 3. a positioning device; 4. a limiting device; 5. a base plate.

The preparation method for the transmission electron microscope slicing sample in the embodiment is a preparation method for an in-situ heating ultrathin slicing sample, and comprises the following steps of:

the method comprises the following steps: rough repair

The rough sample trimming aims at trimming the irregular sample into a regular prismoid, and is mainly completed by a fine grinding all-in-one machine (Leica EM TXP) combined with manual sand grinding and polishing. Firstly, selecting a smooth bottom surface of a cylinder, and respectively performing operations such as milling, grinding and polishing to obtain a smooth plane, wherein the key of the step is to control the feed amount when the peripheral plane is milled, and the feed amount can determine the size of the top plane of the frustum pyramid, so that the length and the width of the top platform are preferably not more than 300 mu m.

Step two: finishing

The sample was transferred to a microtome for fine block trimming. The repair block is assembled and a self-made glass cutter is used, and the cutter is adjusted to enable the left cutting edge to be flush with the midpoint of the plane of the sample. Setting the thickness of each layer to be 300nm, setting the total feed to be 150 mu m, starting automatic sheet trimming, and trimming blocks for multiple times to obtain the boss with flat surface and small enough area (preferably the length and the width are not more than 50 mu m).

Step three: preparation before slicing

The slicing process adopts a wet cutting method. Before slicing, the cutter is adjusted, after the cutter is adjusted, water is filled into the water tank, and the liquid level can be lightly brushed by using a lash brush to ensure that the cutter edges are all contacted with the liquid level.

Step four: automatic slicing

Due to the possible problems of rough surface, empty feed, etc., the sample surface may be further modified by setting the speed to 100mm/s and the slice thickness to 80 nm. After the slices can be stably sliced, the slicing speed is set to be 2-20mm/s, the slice thickness is set to be 50nm, and automatic slicing is started.

Step five: transfer of sliced samples

After the ultrathin section is completed, the section sample needs to be transferred to a heating chip. In order to provide a transfer success rate, a sample transfer device is suggested to assist the transfer of the sliced sample.

The inventor finds out in the research process that the following points need to be paid attention to when slicing:

(1) the sample surface is too large and is liable to cause the slice to wrinkle and crack, so the sample surface after rough trimming and fine trimming should be smooth and preferably rectangular or right-angled trapezoid with length and width less than 50 μm.

(2) According to the strength, hardness and plasticity of the sample material, a homemade glass knife or a diamond knife can be adopted in the process of trimming and slicing, but the diamond knife is relatively expensive. Due to SnSb₂Te₄The hardness is low, so a new glass cutter is adopted for slicing.

(3) The slicing speed in the slicing process depends on the thickness of the sample, and a thinner slice can be obtained by setting a higher speed. The phenomena of creasing, chattering mark, cracking and the like are easy to occur when slicing and sample preparation, so that the later experimental observation is influenced. Therefore, in practical experiments, different slicing parameters need to be set for different samples, and flat and appropriate slices can be cut out through repeated exploration.

The transfer method comprises the following steps:

step one, cleaning an experimental tool:

before slicing, the slicing knife and the water tank are cleaned by deionized water, and the same deionized water is also applicable in the slicing process. Before the slice is transferred, the prepared chip positioning die and the limiting bracket are ultrasonically cleaned by alcohol and dried for later use. Meanwhile, the sample fishing ring 2, the eyelash brush and the like are cleaned by alcohol, so that impurity pollution is prevented.

Step two, preparing a limiting-positioning device for use:

and taking an in-situ heating chip, placing the in-situ heating chip in a limiting support groove to limit the chip from floating, overlapping the positioning die with the chip and ensuring that the hollow part of the positioning die is superposed with the chip heating module (namely the transfer target area).

Step three, slice fishing and transferring:

before the sample is fished, the sample is slightly pulled at the edge of the slicing knife by using a lash brush pen, so that the sample is moved to the center of the water tank. And then the sheet dragging ring is dipped in water and dried at the position without the sample in the water tank to reduce repulsive force caused by surface tension, and then the sheet dragging ring is aligned to the slices floating on the liquid surface to form a water film to pocket the water film, and the water film is transferred to the fixed in-situ chip to ensure that the heating module, the die positioning frame and the slices are positioned on the same straight line, and the heating module, the die positioning frame and the slices are contacted and slowly absorbed with absorbent paper to remove the water on the upper parts of the heating module, the die positioning frame.

Step four, observing by a microscope:

and taking out the heating chip, observing whether the slice transfer is successful under an optical microscope, and if not, reusing the sample fishing ring 2 for sample fishing.

In situ heating experiment

Step one, preparation work:

and after the slice sample is transferred, the in-situ heating chip is arranged on the in-situ heating sample rod of the transmission electron microscope, and then the sample table is placed into the transmission electron microscope to finish the preparation of in-situ heating.

Step two, in-situ heating experiment:

in the experiment, the heating speed is set to be 0.2 ℃/s (can be adjusted according to actual experiment conditions), high-resolution imaging is carried out at a certain temperature point, and an experiment image is obtained after each observation point (at a corresponding temperature) is kept for 10 minutes.

Manufacture of positioning-limiting device

For the problem of difficult sample transfer, a limiting and positioning device for an MEMS chip is designed. The device consists of a groove-shaped limiting device (shown as modules 4 and 5 in figure 2) for fixing the chip and a positioning device (shown as modules 1 and 3 in figure 2) superposed on the chip. The manufacturing method and the working principle are as follows:

(1) chip limiting device

The preparation method comprises the following steps:

step one, preparation and production of the carrying bottom plate 5: a slice not less than 2cm multiplied by 2cm is selected as the bottom plate 5, and the material of the bottom plate 5 in the embodiment of the invention is a glass slide commonly used in a laboratory. And ultrasonically cleaning the bottom plate 5 for 5 minutes by adopting absolute alcohol, and airing for later use.

Step two, preparing and manufacturing a limiting plate: taking a glass slide, preparing three silicon wafers with the thickness of (3-4) × (6-8) mm, placing the above materials in alcohol for ultrasonic treatment for 5 minutes, and drying in the air for later use. The silicon wafer is placed on a glass slide to form a groove shape, and the middle gap is about 5mm (slightly larger than the width of the in-situ chip is suitable, and a waste chip can be placed for reference at first).

Step three, bonding and fixing the limiting plate: the limiting device 4 is adhered and fixed, preferably, a glass slide is placed on a heating plate (heated at about 150 ℃), paraffin is coated on the glass slide, after the glass slide is melted, a silicon wafer is placed, the glass slide can be firmly adhered by reducing the temperature, and if the position of the silicon wafer needs to be adjusted, the glass slide can be adjusted by heating again. Other glues, such as AB glue, can also be used in the bonding process. So far, the chip limiting device 4 is manufactured.

Selection of materials of the limiting device 4: the experiment adopts the silicon chip as the limiting plate, and can also be made of various materials such as iron sheets, aluminum sheets and the like in practical application.

The working principle is as follows: chip stop device 4 mainly plays the fixed action, prevents that the chip from taking place uncontrollable removal because of the effect of liquid level tension in the section transfer process. The limiting device 4 not only improves the transfer success rate, but also can effectively prevent the chip damage caused by improper operation.

(2) Chip positioning die

The preparation method comprises the following steps:

step one, preparing a positioning plate: and (3) placing the silicon wafer with the same width as the chip in alcohol, carrying out ultrasonic treatment for 5 minutes, and airing for later use.

Step two, manufacturing a positioning frame: and comparing the standby positioning silicon wafer with the chip to determine the position of the observation window, and removing the center of the middle part to form a positioning window 1.

Selection of positioning die material: the positioning plate can also be made of aluminum sheets and other materials, a waste chip is adopted in an actual experiment, the position of a heating area of the chip is a square positioning window 1 with the size of about 2 multiplied by 2mm, and a layer of Si is covered on the square positioning window 1₃N₄Film, removal of Si by ultrasonic cleaning₃N₄After the film is formed into a squareThe positioning window 1. The waste chip is adopted as the positioning device 3, so that the material is saved, the processing trouble is saved, and the size and the position of the positioning device 3 are completely matched with those of the chip.

The working principle is as follows: the positioning die is stacked on the heating chip, so that accurate positioning in the transferring process can be realized, the condition that the sample is transferred to deviate from a target area is effectively reduced, and meanwhile, the pollution to the environment around the chip is reduced.

The application principle of the present invention is further explained with reference to the following specific embodiments;

the embodiment of the invention uses SnSb₂Te₄The polycrystalline block material is a research object, and a heating sample is successfully prepared by a method of ultrathin slicing, sample fishing and transferring. SnSb₂Te₄The initial morphology was irregular shaped blocks.

The method comprises the following steps: and (4) roughly trimming the workpiece by a fine grinding all-in-one machine and manual sand paper polishing, and loading the workpiece on an ultrathin slicer after finishing. And during fine trimming, a self-made glass cutter is used, and the cutter is adjusted to enable the left cutting edge to be flush with the midpoint of the plane of the sample. After the slice thickness and the total feeding are set, automatic slice trimming is started, and a boss with a smooth surface and a small enough area is obtained after multiple block trimming.

Step two: after the block trimming operation was completed, slicing was started at a slicing speed of 2mm/s and a slice thickness of 50 nm. The cut pieces were connected into a strip as shown in FIG. 3 (a).

Step three: and successfully transferring the sample to the in-situ heating chip by using the transmission electron microscope copper mesh under the assistance of a limiting-positioning device. As shown in FIG. 3(b), significant SnSb was found at the position of the observation window₂Te₄Ultrathin section samples.

Step four: the composition of the sample flake was determined by energy spectrum analysis, and the material composition ratio was close to that of Sn: Sb: Te ═ 1:2:4, and no phenomenon such as composition segregation was observed, as shown in fig. 4 (a-d). In addition, under a high-resolution image, the crystal lattice of the material is clear and identifiable, which suggests that the sample meets the in-situ heating research of a transmission electron microscope.

Step five: in the experiment, the heating rate was set to 0.2 ℃/s and the heating was carried out at four temperature points of room temperature, 100 ℃, 200 ℃ and 300 DEG CAnd (4) high-resolution imaging, keeping the temperature of each observation point (at the corresponding temperature) for 10min, and then acquiring an experimental image, wherein the experimental result is shown in a graph (e-h) in figure 4. As shown in fig. 4(e), at normal temperature, we selected a crystal grain that can be cleaned and distinguished by two-dimensional lattice as the research target. On the whole, the region shows a good crystal structure and a clear crystal lattice at the experimental temperature, which shows that the SnSb can be realized by the method₂Te₄And (3) researching an in-situ high-resolution crystal structure of the bulk material.

In summary, the advantages and positive effects of the invention are:

the transmission electron microscope sample preparation and transfer method has the characteristics of low cost, high efficiency, convenience, flexibility, safety, reliability, wide application range and the like. Now briefly described as follows:

the cost is low: in the invention, all the materials used for preparing the sample transfer auxiliary device are simple and easily available, and can be recycled after once preparation. Meanwhile, compared with methods such as focused ion beam cutting (FIB) and the like, the ultrathin section method is used for preparing the heating sample, and can greatly reduce the cost of sample preparation.

High efficiency and flexibility: the ultrathin section method for preparing samples has lower requirements on sample preparation environment. And the auxiliary device in the transfer process effectively improves the success rate of transfer.

Safe and reliable: the whole sample preparation process can be observed under an optical microscope, and meanwhile, the whole sample preparation process can be connected with a computer to observe and store process images, so that the process is safe and controllable. The use of the chip positioning die in the auxiliary device effectively reduces the condition that a sample is transferred to deviate from a target area, reduces the pollution to the environment around the chip, can effectively protect equipment from running and prolongs the service life.

The application range is wide: the method is suitable for block and powder (embedded by resin) samples, and is suitable for different heating chips and different electron microscopes. The sample transfer method is also suitable for various film materials, and also supports various methods such as thermal evaporation films and the like to prepare samples.

In general, the method improves the transfer efficiency and reduces the experiment cost while preparing high-quality sample slices, so that the method is worth popularizing in the transmission electron microscope test and in-situ heating experiment processes of conventional block and powder samples.

The above description is only an embodiment of the present invention, and the common general knowledge of the known specific structures and characteristics in the scheme is not described too much, it should be noted that, for those skilled in the art, it can make several variations and modifications without departing from the structure of the present invention, and these should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.