Original title: How to improve the service efficiency and service life of drill rods in daily drilling operations! Conical drill rod is a very common rock drilling tool in drilling operations, and its quality directly affects the efficiency and duration of rock drilling. We are all eager for an efficient and durable high-quality drill rod, which saves time and effort. So, in addition to choosing a brand drill rod with quality assurance, what other tips can help us improve the efficiency and life of the drill rod? Today we will summarize it for you. 1. How to select a suitable drill rod: 1. When selecting drill rods, please be familiar with the technical performance of the rock drilling equipment you own or will own. 2. Select the drilling and blasting method correctly according to the rock conditions and construction conditions, so as to determine the specification and model of the drill rod, the length of the drill rod, the connection method, the form and diameter of the drill bit. 3. When there are many abnormal fractures of the selected drill rod, the blasting method shall be adjusted in time and the appropriate drill rod shall be selected. Uch as changing the use length of the drill rod, the section size of the drill rod, the diameter of a drill bit, and the like. 4. Select the drill rod manufacturer according to the rock drilling equipment and rock drilling conditions. It is recommended that the rock drill and the supporting drill rod and drill bit can be selected from the same manufacturer, so as to obtain better matching and cost performance, and obtain the maximum use benefit with the minimum investment. II. Preparations before using the drill rod: 1. Check the appearance quality of the drill rod. For example, whether there are defects on the surface of the drill rod that affect its use, whether the straightness of the drill rod is good, etc. Some of these factors are caused by the handling process. Users of drill rods with slight bending can solve the problem on site. Please do not use hammering when straightening. 2. Check whether the drill rod is well matched with the drill bit, otherwise, rock drilling tools , the drill bit is easy to break. Pay attention to the wear of the drill bit blade. If the drill bit with abnormal damage continues to be used, on the one hand, it will be scrapped in advance, and on the other hand, the service life of the drill rod will be greatly reduced. Expand the full text 3. Check the fit between the drill rod and the rock drill and the connecting pieces. Sometimes, the early failure of the drill rod is caused by the wear of the accessories of the rock drill. If the hexagonal sleeve of the pneumatic rock drill is worn seriously, on the one hand, it will cause the drill rod to bear eccentric impact load and break early, on the other hand, it will also accelerate the wear of the internal parts of the rock drill. 4. Check whether the water hole of the drill rod is unblocked. Never use the drill rod with blocked water hole. In this case, the manufacturer will give free exchange. 5. Check whether there is enough cooling water. Rock drilling equipment has certain requirements for water pressure and water quantity. On the one hand, it can help you improve the drilling speed; on the other hand, it can prevent the temperature of the drill rod from rising during use, which will change the material properties of the rod body and cause the early failure of the drill rod. III. Precautions during use of drill rod: 1. Skilled rock drill operators can well adjust the working state of rock drilling equipment during drilling and rock drilling. For example, when opening the hole, the air volume shall be reduced, and low impact force, slow propulsion force and low revolution shall be used to avoid the damage to the drill bit caused by the high stress on the hard alloy sheet when the drill rod is bent. The normal air volume shall be used after the drill bit is completely drilled into the rock. Ensure that the drill rod and the blast hole are in a straight line during rock drilling. 2. Do not hammer the tool with a heavy object or mark the tool improperly. Scars and sharp notches on the surface of the tool will cause early failure of the tool. 3. Avoid empty drilling, which is the most harmful to the drill rod. 4. If the drill bit is broken during use, it can be used after grinding. 5. When unloading the drill bit, it is forbidden to knock and smash, and the drill bit shall be removed with a drill rod remover. 6. After the completion of rock drilling, the surface of the drill rod shall be kept dry as far as possible,dhd drill bit, and the drill rod shall be placed vertically in a dry place to ensure that it is not exposed to rain and water, so as to prevent the service life of the drill rod from being shortened due to serious corrosion. Above analysis hopes to be able to help everybody! If you want to know more about the relevant knowledge, you can continue to pay attention to us. Return to Sohu to see more Responsible Editor:. wt-dthtools.com

Original Title: Drilling Processing (I) 1. Drilling type and its application The drilling processing method for steel structure engineering mainly uses drill bit processing, shearing processing and gas cutting processing, and its application range is divided by the hole diameter and the plate thickness of the part, which is roughly as shown in Figure 1. In addition, although the drilling using laser processing and electric ion processing has been reviewed recently, it has not yet reached the stage of formal practical application due to the limitation of applicable board thickness. In addition, the processing method used to distinguish the purpose and use of drilling is shown in Table 1. 2. Drill hole with drill bit The drilling method using a drill bit is suitable for the NC machining method, and the progress in the past ten years is very striking. As is well known, the drill machining method is a kind of cutting machining, which is a deformation of a tool machining method for cutting a surface with a material harder than the material to be machined. The tool is processed into a spiral shape as a drill, and the drill is pressurized and rotated to perform a circular cutting process. The principle is shown in fig. 2. Because there is little thermal change in the base material during machining and there is little hardening of the machined surface, excellent characteristics of high hole accuracy are used in a wide range of fields, and also become the mainstream of drilling machining methods in steel skeleton engineering. Expand the full text a. Type of drill bit Table 2 shows the types and characteristics of the drill bits used in the drill bit drilling method, and Table 3 shows the oil (water) feeding method of cutting oil or cutting water. b. Grinding of drill bit (Figure 3) The dimensional accuracy of the hole diameter is affected by the grinding of the drill bit, and if it is poor, not only the hole diameter will become larger, but also it will not become a true circle. When grinding by hand, be sure to use the residual material for trial drilling to confirm the accuracy of the hole diameter. Therefore, it is desirable to use a grinder for the grinding of the drill. The standard of the front end angle of the drill bit is 118 118. On the other hand, in the case of using the so-called straight grinding with the front end angle of 150 150 to 180 180, compared with the standard angle,overburden drilling systems, it is possible to drill at the correct position at the beginning of drilling, and there is an advantage that there is less burr in the feed of the drill before the hole is penetrated. However, in-line lapping is not suitable for the drilling of overlapping plates or the deep hole processing of thick plates. In addition, the cutting speed at the central part of the drill is extremely small, so that the drill cannot cut, and the cutting material is forcibly crushed to advance. Thining of the drill tip is performed for the purpose of sharpening the center portion and discharging the chips well, and as shown in fig. 4, there are S-type,fastest dth hammer, X-type, N-type, and their combinations, among which the S-type is widely used. c. Drilling method (1) Drilling period The occurrence of shrinkage and deformation cause by welding in that weld structure portion is unavoidable, and therefore, the drilling time in the manufacturing process has a great influence on the accuracy of the finis product. In particular, the dimensional accuracy between the holes in the construction site joint of the column or beam immediately affects the finishing accuracy of the steel skeleton. Therefore, the drilling period of the member, except for an additional plate or a joint plate, is 1. Make a sample of the hole on the material sheet in advance, and then make a sample confirmation after the assembly, welding and deformation correction, and then make a drilling process. 2. Drill the hole at one end of the material sheet first, and then drill the hole at the other end after assembly, welding, Borehole Drill Bits ,Mining Drilling Equipment, and deformation correction. 3. After the welding and deformation correction of the parts, the two ends shall be finished, and the drilling shall be carried out on the basis of the finished surface. 4. The shrinkage caused by welding and deformation correction of the material sheet is predicted first, and the shrinkage is added to the material for drilling processing and assembly. Among them, 1-3 is implemented when it is difficult to predict the welding shrinkage due to the complex structure, and the operation efficiency of the reversal, sample dropping, drilling and processing of the parts is lower than “.” Can accurately predict that amount of shrinkage, can reduce the cost, and is an excellent proces method. Therefore, it is necessary to collect shrinkage data frequently, and after full review, it should be collated into processing data for proper storage. In addition, the NC drilling machine is widely used recently, and its specialty is that the drilling accuracy is good, while the general joint hole of parts is “” as the mainstream. (2) Drilling The application of NC drill machines, which do not require sample drop, has been increasing in order to prevent that decrease in accuracy and efficiency caused by the use of sample drop for each hole or the drilling of holes one by one in accordance with the sample drop, for the drilling of parts such as holes in a field joint, which are required to have dimensional accuracy relative to each other at the hole position. For the drilling of the small and medium plates such as the spliced plate or the connecting plate which are not operated by the NC machine, it is desired to use a correctly manufactured template for the overlapping drilling, or to use a multi-spindle drilling machine, a profile drilling machine, etc. If you want to use the template repeatedly, it is better to embed it in the template. Quenched sleeve. The pressing force and the number of revolutions of the drill during drilling are different depending on the material of the material to be processed, the type of the drill, the cooling method, etc., and it is necessary to select the correct conditions in advance. In order to increase the drilling speed, drilling with unreasonable pressure or number of revolutions will not only cause large burrs or poor hole diameter accuracy, but also cause mechanical failure and safety problems, which should be avoided. (3) Treatment after drilling The burr of the hole on the joint surface must be removed. Especially in the high tension bolt friction joint, it is to make the parts close to each other, and the friction force is used to ensure the endurance, so the close joint between the parts is particularly important, and there must be no foreign matter mixed in. In addition, the rust, black skin, oil, paint, etc. on the joint surface shall be completely removed. On the other hand, there are the following three methods for the treatment of the friction surface of the high tension bolt joint, the drilling period, and the removal of burrs. 1. Drill holes in the black skin state, remove the burrs, and then use sandblasting to ensure that the roughness of the friction surface is more than 50 μmRy. 2. Similarly, after drilling in the black skin state,mining dth bit, remove the burrs with a grinder and treat the friction surface to make red rust. 3. Sand blasting is used before drilling to ensure that the roughness of the friction surface is more than 50 μmRy. At this time, in ord to treat that burrs and the like generate during the drilling, a method of removing only the burr is required if the friction surface around the hole is not rusted due to adverse effects caused by a commonly used surface grinder. To be continued. Return to Sohu to see more Responsible Editor:. wt-dthtools.com

Original Title: The Truth, Composition Analysis of Various Brands of Cemented Carbide Cemented carbide is used in industrial cutting, mining drill and other fields. Because of its hard characteristics and the requirements of application scenarios, its composition analysis has become a popular testing project. Usually, cemented carbide has a special coating process to make the surface of the blade smooth, thus reducing friction and making chip removal smoother. In addition, the toughness and hardness of cemented carbide are higher, and it has good thermal stability and chemical stability. All these require the analysis of alloy composition to study and control. Today we will give you a detailed analysis of various brands of cemented carbide. I. Composition Analysis of Coated Cemented Carbide CVD Grade 1. Composition analysis of YBC151 cemented carbide: combination of high wear resistance matrix and MT-TiCN, thick Al2O3, TiN coating; suitable for finish machining of steel. 2. Composition analysis of YBC251 cemented carbide: it is an excellent combination of ductile matrix with good cutting edge safety and MTTiCN, thick Al2O3 and TiN coating; it is suitable for semi-finishing of steel. 3. Composition analysis of YBM351 cemented carbide: The special structure matrix is combined with TiCN, thin Al2O3 and TiN coatings, which has good resistance to diffusion wear and plastic deformation, as well as good impact resistance, and is suitable for finish machining, semi-finish machining and rough machining of stainless steel. 4. Composition analysis of YBM251 cemented carbide: The matrix with good toughness and strength is combined with TiCN, thin Al2O3 and TiN coatings, which is suitable for semi-finishing and rough machining of stainless steel. 5. Composition analysis of YBD151 cemented carbide: It is an excellent combination of high wear-resistant substrate and MT-Ti (CN), thick Al2O3 and TiN coating,DHD Drill bit, which is suitable for finish machining and semi-finish machining of cast iron materials. 6. Composition analysis of YBC351 cemented carbide: combination of high strength and plastic deformation resistance matrix with MT-TiCN, thick Al2O3 and TiN coating; good toughness and plastic deformation resistance, suitable for rough machining of steel. Expand the full text 2. Composition analysis of the second generation YBC cemented carbide for black diamond blade 1. Composition analysis of YBC152 cemented carbide: thick TiCN and thick Al2O3 coating can greatly improve the wear resistance while improving the impact toughness. It is an ideal choice for high-speed cutting from steel finishing to semi-finishing. The cutting speed can be increased by more than 25%, and the tool life can be increased by more than 30% at the same cutting speed. 2. Composition analysis of cemented carbide of grade YBC252: thick TiCN and thick Al2O3 coating are adopted, which has extremely strong plastic deformation resistance and cutting edge strength, and is the general preferred grade for steel from finish machining to rough machining. It has stable performance under high removal rate cutting parameters or harsh working conditions, and can achieve more green and environmentally friendly dry cutting. Under the same cutting conditions,dth button bits, the cutting speed can be increased by more than 25%, and the tool life can be increased by more than 30% at the same cutting speed. III. Composition analysis of the second generation YBD cemented carbide of the black diamond blade: 1. Composition analysis of YBD052 cemented carbide: CVD coating grade, (ultra-thick Al2O3 + thick TiCN) coating is combined with the hard substrate, with smooth surface and ultra-fine grains. Xcellent wear resistance in dry high speed cutting of gray cast iron. 2. Composition analysis of cemented carbide of grade YBD102: CVD coating grade, (thick Al2O3 + thick TiCN) coating is combined with hard substrate, which reflects good wear resistance and impact resistance during high-speed machining of ductile iron. 3. Composition analysis of cemented carbide of grade YBD152: CVD coating grade, (medium thick Al2O3 + thick TiCN) coating is combined with hard substrate, with good spalling resistance, suitable for medium and high speed turning of cast iron, and can withstand slight intermittent cutting at medium speed. This grade also has a strong versatility when applied to the milling of cast iron. 4. Composition analysis of cemented carbide of grade YBD252: CVD coating grade, (medium thick Al2O3 + thick TiCN) coating is combined with hard substrate, with good combination of wear resistance and toughness. It is suitable for medium and low speed wet milling of cast iron with toughness requirements (such as ductile cast iron), and also suitable for turning under intermittent conditions. . IV. Composition analysis of PVD grades of nano-coated cemented carbide 1. Composition analysis of YBG102 cemented carbide: nc-TiAlN coating is combined with fine particle matrix, mining drill bit ,Tapered Rock Bit, which is suitable for light and medium load milling of various materials (especially for cast iron) and fine and semi-fine turning of high-temperature alloys. 2. Composition analysis of YBG202 cemented carbide: The nc-TiAlN coating is combined with the strong and tough matrix of ultrafine particles, which is suitable for light and medium load milling and hole processing of various processed materials, as well as fine and semi-fine turning of stainless steel and rough turning of superalloy. 3. Composition analysis of YBG302 cemented carbide: The nc-TiAlN coating is combined with the tough cemented carbide matrix, which is suitable for medium-load milling, hole processing, cutting and grooving of various processed materials, as well as semi-finish and rough turning of stainless steel, realizing the perfect combination of safety and wear resistance. 5. Composition analysis of cermet cemented carbide: Composition analysis of cemented carbide YNG151 and YNG151C The Ti (CN) -based cermet cutting tool has high chemical stability between the cutting tool and a material to be machined, The temperature of the cutting edge is reduced, so that the mutual diffusion of atoms between the tool and the workpiece material is effectively prevented, and the adhesive wear resistance is improved. Try to improve. Therefore, Ti (CN) -based cermets exhibit good red hardness and excellent resistance to wear under high speed machining condition It is an ideal tool material for high speed machining and semi-finish machining of steel, and its high temperature strength is harder than WC-Co. The alloy has high quality, and the toughness is better than that of Al2O3 and Si3N4 ceramic cutting tools, thereby filling the gap between WC-based hard alloy and Al2O3 and Si3N4 ceramics in the fields of high-speed finish machining and semi-finish machining. VI. Composition analysis of cemented carbide for superhard blade: 1. Composition analysis of PCB N cubic boron nitride cemented carbide: PCBN cutting tools have high hardness and excellent thermal stability, and the cutting temperature can reach 1300 oC. It is mainly applicable to the machining of HRC50-60 hardened steel (such as carbon tool steel, bearing steel, die steel and high-speed steel), gray cast iron, ductile cast iron, chilled cast iron and Ni-based, Co-based, Cr-based and Fe-based high-temperature alloys. 2. Composition analysis of cemented carbide of PCD polycrystalline diamond: PCD cutting tools have high hardness, excellent wear resistance, low friction coefficient and excellent thermal conductivity. It It is suitable for cutting non-ferrous metals (such as Cu, Al, Mg, Ti, high-silicon aluminum alloy, etc.) And non-metallic materials (such as glass fiber, ceramics, reinforced plastics, etc.). 3. Composition analysis of YCB011 cemented carbide: PCBN with high CBN content has high hardness (HV3400-3800), thermal stability, thermal conductivity and good wear resistance. It is mainly used for high-speed and high-precision cutting of cast iron, iron-based P/M materials and heat-resistant alloys. 4. Composition analysis of YCB012 cemented carbide: low CBN content, fine grain structure, PCBN grade, high hardness (HV3200-3500), good thermal stability and relatively low thermal conductivity. It is mainly used for high-speed, high-precision continuous or slight intermittent cutting of hardened steel (HRC45-65). Dry cutting is recommended as much as possible. 5. Composition analysis of YCD011 cemented carbide: PCD grade with medium grain structure has extremely high hardness (HV7000), excellent wear resistance and thermal conductivity. It is mainly used for high-speed, high-efficiency and high-precision cutting of non-ferrous metals (Al,dth hammer bit, Cu and their alloys) and non-metals (ceramics, wood and reinforced plastics, etc.). It is a PCD grade with good versatility. Return to Sohu to see more Responsible Editor:. wt-dthtools.com

Original title: How many minutes does it take to drill 1 meter with a drilling rig? YWG series down-the-hole drilling machine is a new type of highly integrated down-the-hole drilling machine independently developed by our company. The machine adopts full hydraulic control, makes full use of the excavator hydraulic system, is highly integrated, convenient and fast, and is widely used in mining, photovoltaic pile foundation and other fields; When used with column splitter, it can greatly improve the working efficiency. This model has the advantages of low comprehensive energy consumption,dth drill bits, high energy utilization rate and high cost performance. It is a wise choice for your down-the-hole operation. 2. Product application: drilling of blasting holes in various rocks and reinforced concrete. Application area: engineering field: earthwork, demolition engineering, road and bridge engineering,dth drilling hammer, tunneling engineering, (non) excavation engineering, water conservancy engineering, etc. Mining field: stone mining (marble, granite, dth rock bit ,down the hole bit, sandstone, limestone, etc.), metal mining, coal mining, sand mining, etc. 3. Advantages of the product: 1. Wide range of models to choose from a variety of hydraulic rock drills, including 20/45/90/115 and other models of rock drills; 2. Convenient loading and unloading, convenient modification, on-site loading and unloading, convenient and rapid; And 3, the rock drilling speed is fast, a hydraulic rock drill is adopted, the rock drilling speed is fully improved, and the rock drilling velocity on the rock with the hardness of 7.6 degrees And 4, the operation is flexible: the rock drill fully combines the advantages of convenient walking of the excavator, rock drilling speed of the rock drill and the like, and can be suitable for rock drilling operation under complex working conditions. And 5, that dig cost is low: through the transformation of the excavator,mining dth bit, the excavator has the rock drilling function of the rock drill and does not affect the function of the excavator, and the price is only 1/10 of that of a hydraulic rock drilling jumbo, and is even lower than that of a pneumatic rock drill jumbo. Return to Sohu to see more Responsible Editor:. wt-dthtools.com

Original Title: RNA Extraction and Preparation Methods for Common Medical Samples As a kind of very important biological macromolecule, nucleic acid is the master in the biological world. It plays an important role in all life activities such as reproduction, development, maintenance, aging and death of organisms. If there is a slight change in its structure, such as an error, deletion or addition of a base, It may lead to mutation, defect or disease, so nucleic acid has become a hot research topic in biochemistry, genetics and other related life disciplines, and its wide coverage and rapid progress are beyond the reach of other disciplines. The first prerequisite for nucleic acid research is to extract nucleic acid from many complex biological macromolecules and purify it to a certain extent so as to carry out corresponding scientific research and practical application. Nucleic acid, coming to the “tube”, is divided into six phases. Through this series, we share with you the knowledge of sample preparation, extraction methods and detection of nucleic acid extraction, in order to be helpful to your scientific research. 1 Whole blood sample 01 Selection of blood collection tube One of the major problems with blood collection for testing is the instability of intracellular RNA, which degrades rapidly within hours of blood collection. In addition, RNA from some species is increased in vitro by genetic induction after blood collection. Both in vitro RNA degradation and gene induction can lead to an underestimation or overestimation of the number of transcripts of relevant genes in vivo. BD’s PAXgene blood RNA tubes contain additives that stabilize gene transcription in vivo, reduce RNA degradation in vitro, and minimize the level of gene induction. They are suitable for human and primate whole blood sample preparation. For whole blood samples, we only recommend the use of this tube. BD PAXgene Blood RNA Tube (Item No.762165) 02 Collect blood Please read the product instructions carefully before using the PAXgene blood RNA tube for correct operation. If the PAXgene Blood RNA tube is the only blood drawing tube, the blood should be drawn into a “waste tube” prior to being drawn into the PAXgene Blood RNA tube so that the phlebotomizer used in the blood drawing process can be prefilled with blood; otherwise, the PAXgen Blood RNA tube should be the last tube in the blood drawing procedure. Make sure that the blood has stopped flowing into the tube before removing the tube from the needle holder (the negative pressure in the PAXgene Blood RNA tube is designed to draw 2.5ml of blood into the tube). Immediately after blood collection, the PAXgene blood RNA tube should be gently inverted 8-10 times to ensure that the protective agent and blood in the tube are well mixed. Expand the full text 03 Preservation and transportation PAXgene blood RNA tube are allowed to stand vertically at room temperature (18-25. degree. C.) for 2-24 hour, after which they may be stored at -20. degree. C. or lower; if that tube are to be stored at a temperature lower than -20. degrees. C., the tubes may be frozen at -20. degrees. C. for 24 hours, and then transferred to -70. degree. C or -80. deg. C for at least 50 months. Bulk dry ice transport. 2 Serum Plasma Samples Because the abundance of RNA in cells is much higher than that of free RNA in blood, even a very small amount of cells will have a great impact on the analysis of free RNA in blood. Therefore, removing the contamination of cells and cell debris is the key to the preparation of serum plasma samples. 01 Selection of blood collection tube For serum samples, it is enough to use common serum vacuum blood collection tubes; for plasma samples, it is recommended to use EDTA anticoagulant tubes, and heparin anticoagulant tubes are prohibited. 02 Separation and storage of plasma samples Collect blood samples with EDTA anticoagulant tube (the collected blood samples can be stored at room temperature or 4 ℃ for a short time, but not more than 1 H). 1900 G (or 3000 rpm), 4 ℃, centrifugation for 10 min. Carefully transfer the upper plasma layer (yellow) into a new 1.5 ml centrifuge tube without the tip of the gun touching the middle layer (white blood cell and platelet layers). In general, 4 to 5 ml of plasma can be separated from 10 ml of blood. The separated plasma was centrifuged at 16000 G, 4 ℃ for 10 min. Do not touch the impurities on the bottom side of the tube with the gun head. Carefully transfer the supernatant to a new 1.5ml centrifuge tube and store it at -80 ℃. Bulk dry ice transport. Plasma samples were isolated 03 Separation and preservation of serum samples Blood samples were collected with blood collection tubes containing coagulation activators or ordinary vacuum blood collection tubes, and the blood was allowed to coagulate at room temperature for 10-60 min. 1900 G (or 3000 rpm), 4 ℃, centrifugation for 10 min. Carefully transfer the upper serum (yellow) to a new 1.5 ml centrifuge tube without the tip of the gun touching the middle layer (white blood cell and platelet layers). In general, 3-5ml of serum can be separated from 10ml of blood. The separated serum was centrifuged for 10 min at 4 ℃ with a 16000 of G. Do not touch the impurities on the bottom side of the tube with the gun head. Carefully transfer the supernatant to a new 1.5ml centrifuge tube and store it at -80 ℃. Bulk dry ice transport. Serum sample separation 3 cell supernatant Cell culture media or other biological fluids are collected using a suitable container. 3000 G, 4 ℃, 15 min. Carefully transfer the supernatant to a new sterile centrifuge tube. The supernatant was centrifuged at 4 ℃ for 10 min with a 16000 of G. Do not touch the impurities on the bottom side of the tube with the gun head. Carefully transfer the supernatant to a new sterile centrifuge tube and store it at -80 ℃. Bulk dry ice transport. Cell supernatant separation 4 Exosomes For the teacher’s own enriched exosomes, it is necessary to dissolve the exosomes in not more than 100ul RNase-free PBS and mix them well to facilitate subsequent extraction. The exosomes sample solution was stored at -80 ° C. Bulk dry ice transport. 5 Tissue samples For oral tissue samples used for RNA extraction, if the sample volume is small, it is recommended to give priority to the sample delivery method of protective solution (RNAlater, cbd centrifugal extractor ,thin film distillation, etc.). Scheme I. Sample delivery of protective solution (RNAlater, etc.) The fresh tissue was cut into samples with length, width and height ≤ 0.5 cm with a scalpel, and small organs such as mouse liver, kidney and spleen could be preserved intact in RNA later. Immerse the tissue sample in 5-10 times the volume of the RNAlater to completely submerge the tissue. Samples were incubated overnight at 4 ° C (to allow complete tissue penetration by RNAlater) and then transferred to -80 ° C for long-term storage. Bulk dry ice transport. Scheme II: Liquid nitrogen quick freezing and sample delivery Fresh tissue was removed, and tissue types not required for the study, such as connective tissue and adipose tissue, were immediately removed. If the tissue volume was large, the tissue should be cut into small pieces (soybean size) with length, width and height ≤ 0.5 cm. The tissue surface was quickly flushed clean of residual blood with precooled PBS solution (RNase free) or saline. The processed tissue samples are mixed evenly and stored in a liquid nitrogen pre-freezing storage tube with a screw cap. Quickly frozen in liquid nitrogen for about 3 H, and then transferred to -80 ℃ for long-term storage. Bulk dry ice transport. Caution: 1. For For the cancer samples of RNA projects, we suggest that the tissues removed by surgery should be quickly put into RNAlater and incubated at 4 ℃ for 24 hours, then the RNA later should be discarded, the tissues in the necrotic area and the paracancerous tissues should be cut off and transferred to the liquid nitrogen pre-freezing storage tube with a screw cap. The liquid nitrogen is quickly frozen, stored at -80 ℃, and transported with dry ice. 2. After the tissue sample leaves the living body It is suggested that liquid nitrogen quick freezing should be carried out within 3 min. The longer the operation time before quick freezing, the greater the possibility of RNA degradation. 3. Tissue samples are not recommended TRIzol sample delivery, if necessary, need to be fully ground in liquid nitrogen and dissolved in an appropriate amount of TRIzol, tissue samples should not be excessive, after 5 minutes of pyrolysis at room temperature, frozen at -80 C, dry ice transportation. 6 cell sample The number of cells required for one RNA extraction reaction is less than or equal to 1 X 10 ^ 7, and the number of cells required for one RNA extraction reaction is preferably between 3 X 10 ^ 6 and 1 X 10 ^ 7. If the sample volume is large, it is recommended to divide the cell sample into different tubes according to the above requirements. 01 Adherent cells Take out the adherent cultured cells from the incubator, observe the cells under the microscope, and confirm that the growth state is good (the normal cell fusion degree is about 80%). The medium was discarded, and 5 mL of PBS (RNase-free, room temperature) was added to the cell culture flask or dish and washed once. Discard the PBS, add a proper amount of TRIzol, and repeatedly suck and beat for several times until the agglomerated cell mass is not visible, so that it can be fully dissolved in the lysis solution to form a clear and non-viscous liquid. The lysed cell solution was transferred to a 1.5 mL screw-cap centrifuge tube (RNase-free), stored at -80 ℃ for a long time, and transported in large volume of dry ice. 02 Suspension cells First of all, make sure that the cells are growing well; centrifuge to get the cell sediment (according to the steps of cell centrifugation in the customer’s laboratory, note that the cell centrifugation should be moderate, and do not make the cell centrifugation too solid to cause the lysate can not fully penetrate). Discard the medium, add 1 mL of PBS (RNase free, room temperature), gently suspend the cell pellet, and transfer to a 2 mL screw-top, tip-bottom centrifuge tube (RNase free). Centrifuge (according to the steps of cell centrifugation in the customer’s laboratory, note that the cell centrifugation should be moderate, and do not make the cell centrifugation too solid to cause the lysate can not fully penetrate) to obtain cell sediment, discard PBS, add appropriate amount of TRIzol, and repeatedly suck and beat for several times until no agglomerated cell mass can be seen, so that it can be fully dissolved in the lysate. It is stored at -80 ℃ for a long time and transported in large volume of dry ice. Caution: 1. If it is DNA items can be washed with ordinary sterile PBS. If it is RNA items, it must be RNA se-free. 2. Trypsin treatment is not recommended for obtaining cell Pancreatin is protein, and if there is any residue, it will affect subsequent experiments. 3. The number of cells is less than 5 × 105 It is recommended to send the sample directly after quick freezing (without lysis with lysis solution). Due to the small number of cells,molecular distillation systems, we will arrange micro-extraction. 4. Cell samples are not recommended to be stored in RNAlater tissue RNA protection solution, because of the high density of RNAlater, the cells stored in it are difficult to be collected by centrifugation for extraction. Return to Sohu to see more Responsible Editor:. toptiontech.com