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What is a magnetic polishing machine and what is the principle of a magnetic polishing machine? Magnetic polishing machine is also called magnetic tumbler. This polishing equipment breaks through the traditional vibration grinding and polishing concept. It uses magnetic force to drag the stainless steel needle grinding material to produce rapid rotational motion, thereby achieving multiple effects such as burr removal, polishing, and cleaning. Utilizing its unique magnetic field distribution to produce a strong and stable magnetic induction effect, the magnetic steel needle and the workpiece are fully ground in all directions and at multiple angles to achieve rapid rust removal, dead corners, burr removal, oxide film and sintering traces. and other effects. Especially for workpieces with complex shapes, porous gaps, internal and external threads, etc., it can show its magical effect. It does not damage the surface of the workpiece and does not affect the accuracy of the workpiece. Make the workpiece instantly smooth, tidy and brand new. Suitable for grinding and polishing gold, silver, copper, aluminum, zinc, magnesium, iron, stainless steel and other metals and non-metallic workpieces such as hard plastics. After being processed by this type of polishing machine, the surface of the workpiece will show the original metallic luster, which is bright and round and has a visual effect; it can also release part of the internal stress of the workpiece and improve the mechanical properties of the workpiece; strengthen the surface quality of the workpiece and improve the surface performance. Features of magnetic polishing machine1. Achieve multiple functions such as deburring, chamfering, polishing, and cleaning;2. For irregular-shaped parts, dead corners such as holes and tubes, and cracks can be polished without any dead corners;3. The equipment can set the time, the processing speed is fast, the operation is simple and safe, the end reminder can remind the polishing to be completed, and one person can operate multiple machines; the polishing process does not require manual intervention;4. Variable frequency adjustment to meet various polishing needs. Stainless steel needles are available in different diameters from 0.2-5MM to 1.2-10MM;5. After grinding, the workpiece will never be deformed, the surface will not be damaged, the accuracy will not be affected, and the shape and size will not change. The surface roughness value can reach Ra0.1-Ra0.01, and the surface shows bright metallic luster;6. Low cost, the grinding time is about 2-20 minutes to complete; the operation is simple, convenient, completely technology-free, and can be operated by multiple machines;Application scope of magnetic polishing machineSuitable for grinding and polishing gold, silver, copper, aluminum, zinc, magnesium, titanium, stainless steel and other metals and non-metallic workpieces such as hard plastics.Such as: 1. Precision stamping parts; 2. Stainless steel, copper and other metal parts, screw threads; 3. Magnesium aluminum die-cast parts;4. Zinc and aluminum die-cast parts; 5. Precision spring and spring parts; 6. Electronic, computer, and communication parts;7. Centering, tooling, CNC automatic lathe parts; 8. Mobile phone casing, communication metal casingDisadvantages of magnetic polishing machine:1. The consumables are the martensite stainless steel needle and the grinding fluid used;2. The current and voltage required for work are relatively large, which can easily cause safety hazards; 3. Power consumption is fast, machine parts wear out quickly, and maintenance costs are relatively high;

Stretch forming is a stamping processing method that uses a mold to form a flat blank into an open hollow part. As one of the main stamping processes, drawing is widely used. Thin-walled parts with cylindrical, rectangular, stepped shapes, spherical, tapered, parabolic and other irregular shapes can be made by the drawing process, and more complex parts can also be manufactured if combined with other stamping and forming processes. The use of stamping equipment for the stretching and forming of products, including: drawing, redrawing, reverse drawing, thinning and drawing. Stretching process: Using the pressing plate device, using the punching force of the punch, part or all of the flat plate is pulled into the cavity of the concave mold and shaped into a container with a bottom. Stretching of the side wall of the container parallel to the direction of stretching is a simple stretching process, while stretching of conical (or corner pyramid) containers, hemispherical containers, parabolic containers, etc., also includes expansion processing.   Re-drawing process: that is, for the deep-drawn products that cannot be completed by one stretching process, the formed products that are stretched again need to be stretched to increase the depth of the shaped container.  Reverse drawing machining: This is a process in which the stretched workpiece of the previous process is reversed stretched, and the inside of the workpiece becomes the outside, and the outer diameter is reduced.   Thinning and stretching processing: the formed container is squeezed into the concave mold cavity slightly smaller than the outer diameter of the container with punch, so that the outer diameter of the container with a bottom becomes smaller, and the wall thickness becomes thinner, which not only eliminates the deviation of wall thickness, but also makes the surface of the container smooth. When using stamping equipment for metal stamping and drawing processing, the following 16 types are included:   01 Round drawing Stretching of products with flanged (flanged) cylinders. The flange and the bottom are both plane shaped, the side wall of the cylinder is axisymmetric, and the deformation is evenly distributed in the same circumference, and the blank on the flange produces drawing deformation. 02 Ellipse drawing The deformation of the blank on the flange is tensile deformation, but the amount of deformation and the deformation ratio change accordingly along the shape of the profile. The greater the curvature, the greater the plastic deformation of the blank, and conversely, the smaller the curvature, the smaller the plastic deformation of the blank. 03 Rectangular drawing A low-rectangular part that is formed by a single stretch. When stretched, the tensile resistance at the fillet of the flange deformation zone is greater than that at the straight edge, and the degree of deformation at the fillet is greater than that at the straight edge. 04 Hill drawing When the sidewall of the stamping part is beveled, the sidewall is suspended during the stamping process, and the mold is not attached until the end of forming. The deformation characteristics of different parts of the sidewall are not exactly the same when forming. 05 Hill drawing The blank deformation in the forming process of the mound cover plate is not a simple tensile deformation, but a composite forming with both tensile and bulging deformation. The deformation of the blank on the pressing surface is tensile (tensile stress in the radial direction and compressive stress in the tangential direction), while the deformation of the blank inside the contour (especially in the central area) is a swelling deformation (both radial and tangential tensile stresses). 06 With flange hemisphere drawing When the spherical part is stretched, the blank is in partial contact with the spherical top of the punch, and most of the rest is in an unconstrained free state suspended in the air. Therefore, the main process problem of the stretching of such spherical parts lies in the severe thinning of the local contact part, or the instability and wrinkling of the curved part. 07 Flange drawing The flange part of the stretched product is processed by shallow drawing. The stress-strain profile is similar to that of a compression flange. Due to the tangential compressive stress, it is easy to wrinkle, so the forming limit is mainly limited by compression wrinkling. 08 Flange drawing The flange part of the pre-process stretched product is angled and restretched, which requires the material to have good plasticity. 09 Deep drawing Stretching products that exceed the drawing limit need to be stretched more than twice before they can be completed. Products that have been stretched in the depth direction of the former station are redrawn in the depth direction. Wide-flange stretches are stretched to the required flange diameter for the first stretch and remain the same when they are then stretched. 10 Taper drawing H/d0.8, α=10 ° ~ 30 ° deep conical parts, due to the large depth, the degree of deformation of the blank is larger, only rely on the local area of the blank and punch contact to transmit the forming force, it is easy to cause the blank to be over-thinned and even cracked, and it needs to be gradually formed after many transitions. The stepped stretching method is to first stretch the blank into a stepped transition, the stepped shape is tangent to the inner shape of the tapered part, and finally form a tapered shape. The number of stretching times and process of the stepped transition piece are the same as the stretching of the stepped cylindrical piece. 11 Rectangular redrawing The deformation of a highly rectangular part formed by multiple stretches is not only different from that of a deep cylindrical part, but also from that of a low box-shaped part. The picture shows that when the multi-station automatic conveyor press is processed for high rectangular boxes, the shape and size of the parts change with the stretching height during the multiple stretching process. 12 Surface forming The surface is stretched and formed, so that the outer flange part of the metal flat blank is reduced, and the inner flange part is elongated, and it becomes a stamping and forming method for hollow products with a curved surface shape of non-straight wall and non-flat bottom. 13 Step drawing The left primary drawn product is redrawn and formed into a stepped bottom on the right. The deeper parts are deformed at the beginning of the stretch form, and the shallower parts are deformed at the later stage of the stretch. The sidewall of the changing part of the step is prone to induce shear stress and deformation. 14 Reverse drawing The workpiece that is stretched in the previous process is reversed and re-stretched. The reverse tensile method can increase the radial tensile stress, which can be better for preventing wrinkling. It is also possible to increase the stretch coefficient of restretching. 15 Ironing Different from ordinary stretching, thinning stretching mainly changes the thickness of the cylinder wall of the stretched part during the stretching process. The gap between the convex and concave dies is less than the thickness of the blank, and the straight-walled part of the blank is under the greater uniform compressive stress when passing through the gap, and the wall thickness becomes thinner during the stretching process, while eliminating the deviation of the wall thickness of the container, increasing the smoothness of the surface of the container, and improving the accuracy and strength. 16 Panel drawing Panel products are sheet stamping parts with complex surface shapes. In the drawing process, the deformation of the blank is complex, and its forming properties are no longer simple stretch forming, but compound forming with deep drawing and expansion at the same time.

If your plant is being stretched to its financial limit, you may be looking for ways to simplify some of your processes and procedures. Replacement of underperforming equipment and other costly solutions aren’t always the answer, and sometimes going back to basics can be all you need. For instance, trouble-shooting the root cause of a pump’s failure and repairing the problem rather than replacing it. In keeping with our discussion on the top pump vibration problems, we are going to focus on misalignment of the pump shaft. A pump’s life can be greatly affected by how well it is inspected and maintained. Misalignment of the pump shaft can be one of the leading causes of failure and even a small misalignment of the pump and driver of just 0.0001 inches can decrease the pump’s ability to operate by as many as 85 months. What is Misalignment of the Pump Shaft? Pump shaft misalignment occurs when one shaft or surface is moved from its desired position. These movements can lead to misalignment in the entirety or partial sections of a pumping system. Misalignment in pump shafts can also result in an increase in resultant forces that change the angles and orientations into new resultant load directions. Signs of Misalignment in the Pump Shaft A common error when looking for signs of misalignment in the pump shaft is increased bearing load or premature failure of the bearings. However, it is the vibration of the pump that commonly causes damage in bearings. Only extreme misalignment of the pump shaft can affect the bearing load. Some vibration is normal in pumps. However, even excellent alignment of the pump’s shaft centers does not guarantee the absence of vibration. It’s best to have someone experienced in vibration determine if the cause is indeed pump shaft misalignment, as well as if it’s severe enough to affect the pump’s performance. Which Pumps are Most Likely to Misalign? One factor that greatly affects misalignment of the pump shaft are the bearing types (when used in centrifugal pumps). The SKF group did a study of just that, and the pump types most likely to misalign were: 1. Spherical roller bearing and spherical roller thrust bearing pumps with a “very high” risk for misalignment 2. Single row deep groove ball bearing with a moderate risk of misalignment 3. Single/double row angular contact ball bearing, PumPac bearing set, cylindrical roller bearing, and taper roller bearing set all had low risk of misalignment Solutions for Misalignment of the Pump Shaft A good rule of thumb is that an absolute perfect pump shaft alignment is not realistically possible or necessary. In the past, engineers were told that the shaft’s alignment needed to be within 0.002 inches. Since each pump shaft, type of media, and system configuration are different, using this number as a baseline can be costly. Refer to your owner’s manual or contact an experienced technician to learn what the optimal number is for your plant. One of the most common methods to repair misalignment include close coupling. This is a technique used to join the pump and motor by directly mounting the motor onto the pump. A proper close coupling repair should result in precise alignment as well as a secure hold. This method of repair is also cost effective because it uses s a compact unit instead of a long coupled assembly. A long coupling assembly is more expensive but often necessarily in scenarios where the above is not possible. These include for applications involving high temperatures, high viscosity liquids, and high power requirements. Other repair methods include fixed couplings, flexible couplings, and laser shaft alignment. Conclusion on Misalignment of the Pump Shaft According to the British firm Michael Smith Engineers Ltd, shaft and coupling misalignment account for over 50% of breakdowns in plants. 

How do these large windmills that we see turning day and night convert wind energy into electrical energy?  like airplane wings, the principle of wind turbine is to use wind to drive the windmill blades to rotate, and then drive the generator to generate electricity. Wind turbines' leaves look smaller from the ground, but in fact they are very large, the ordinary ones are more than 40 meters long, and the largest ones length of the blades has exceeded 100 meters at present, far exceeding the length of the wings of large passenger aircraft. In fact, the wind does not "push" the wind turbine blades, but because the shape of the blade cross-section is asymmetrical up and down, flow speed of wind is high when it passes above the blades, which below is smaller. This will cause the pressure above the blade to be small and the pressure below to be strong. The blade will form a pressure difference between the upper and lower parts of the blade. This pressure difference will generate lift, causing the wind wheel to rotate. How does a wind turbine ensure power generation? To convert wind energy into electrical energy, unique airfoil design alone is not enough. Windmill must face the wind to generate electricity. When the wind turbine is working, it first finds the direction of the wind through the wind vane, and then rotates the nose of the aircraft to the direction facing the wind through the yaw system. Wind is very complex. The wind turbine will often measure the wind direction and rotate its head to face the wind, so that the wind turbine can better match the characteristics of the wind. As the angle to the wind increases, the power generation power will also increase rapidly. In addition, the fan blades will also rotate to help the fan better adapt to the wind. Traditional wind turbines use wind to drive the windmill blades to rotate, and then increase the rotation speed through multiple gear sets such as speed increasers to drive the generator to generate electricity. This is a very long transmission process, and energy will inevitably be lost during the transmission process. Direct-drive permanent magnet technology eliminates the need for complex transmission structures such as gearboxes, greatly reduces losses, improves power generation efficiency, and ensures operational reliability. The rotor of the direct-drive permanent magnet power generation is composed of more than 1,300 magnets, and the core components are composed of rare earth materials. It can generate a strong magnetic field without consuming any electric energy, ensuring the unit's strong power generation capacity. When the wind blows the blades, the coils continuously cut the magnetic field lines to generate electricity. This is how wind energy is converted into electricity.   Emitted by wind turbines connected to the grid electricity, can it be directly fed into the power grid for people to use? If you want to safely integrate wind power into the grid for people to use, the wind turbine side current and the grid side current need to be processed by the electrical box. The voltage generated by the wind turbine is constantly changing, and the electricity for using from grid has strict requirements on the incoming voltage. At this time, a transformer is needed to process the wind power that has been generated. After processing, all units can output a unified voltage, and wind power can be transmitted safely.

Why haven’t fuel cells become more popular? When it comes to new energy vehicles, most people define them as "pure electric vehicles", including plug-in hybrid vehicles. To be precise, the "pure electricity" here mainly refers to battery packs. For example, the current mainstream is ternary lithium battery packs, and new technologies such as solid-state batteries will appear in the future. But no matter what kind of battery it is, it has shortcomings, such as charging efficiency, pollution of the battery itself, etc. In this regard, another voice appeared. The best “energy source” for new energy vehicles is actually hydrogen fuel, also known as “hydrogen fuel cell”. At present, new energy car owners all over the world are still using lithium batteries, and hydrogen fuel cells are also very popular. So, what can enable the longer-term development of new energy vehicles, electricity or hydrogen fuel? The difference between ternary lithium battery and hydrogen fuel cell What needs to be noted here is that whether it is ternary lithium battery or hydrogen fuel, it is ultimately electric energy that drives the vehicle. However, the difference is that they come in different forms. Among them, the battery is more like an energy storage device, which directly stores electrical energy and releases it when needed; the hydrogen fuel cell is like a power generation device. But hydrogen fuel itself is not electrically charged, but converts chemical energy into electrical energy through "chemical reactions", and the final form of both is electrical energy. The advantages of hydrogen fuel cells are obvious Why the call for hydrogen fuel cells? I think this has to start with the pain points of traditional batteries. The first is charging time. Everyone knows that if current pure electric vehicles want to obtain a good cruising range, they must be equipped with a large-capacity battery pack. But if the battery pack is too big, the charging time will naturally be short. Even in the fast charging state, it takes more than half an hour to charge 30% to 80% of the electricity, which is far different from the refueling time of traditional fuel vehicles. In addition, the premise is that it supports fast charging, including fast charging equipment and so on. Hydrogen fuels do not have this problem. Take Toyota, which focuses on hydrogen energy, for example. Its hydrogen model only takes 3-5 minutes to refill, which is similar to refueling. It can be said that the efficiency and experience have been greatly improved. In terms of battery life, Toyota's hydrogen-powered vehicles can now reach more than 600 kilometers. Combined with the fast and efficient "energy replenishment" method, hydrogen-powered vehicles are closer to the experience of traditional fuel vehicles. More importantly, hydrogen fuel cells can achieve truly zero pollution. Because only water and heat can be discharged from production to use. However, compared with traditional battery packs, when the battery is scrapped, how to dispose of it without polluting the environment is still a big problem. What limits the widespread application of hydrogen fuel cells? The points mentioned above, including zero pollution, high energy replenishment efficiency, and long cruising range, are enough to make hydrogen fuel cells better than traditional lithium batteries. But why aren't hydrogen fuel cells as popular as lithium batteries? The point is that hydrogen energy itself is special. In simple terms, it's about security, how it's stored, and how it's served. In addition, hydrogen fuel cells have high technical content and higher input costs. Most critically, hydrogen fuel cells can easily explode in the event of an accident. In comparison, traditional batteries are much simpler. As long as there is a power grid or an area with electricity, you can use charging facilities to charge. However, current technology, including input costs, cannot support the large-scale layout of hydrogen energy supply stations. Of course, this is only one aspect. On the other hand, due to the preconceived advantages of electric energy, all major car companies in the world are currently focusing on electric energy. Traditional battery packs include charging facilities, which are pretty much unidirectional. Only in regions like Japan, Toyota has vigorously engaged in hydrogen energy technology, and this technology can only radiate to its own country. In other words, hydrogen energy is more suitable for Japan's national conditions, and in a small area, it can be better realized. Because of this, the global new energy direction is not hydrogen energy. After all, it is difficult to overcome the problem of hydrogen energy and apply it in large quantities in a short period of time. On the contrary, since most people choose electric energy from the beginning, they will work together in one direction. I believe that pure electric vehicles will make rapid progress.  

Synchrotron light source Electromagnetic radiation is so useful that we can transmit music wirelessly over long distances. It works like a giant microscope, harnessing the power of electrons to produce bright light that scientists can use to study anything from fossils to jet engines to viruses and vaccines.A good way to get high levels of electromagnetic radiation is to use synchrotrons to emit synchrotron radiation from electrons.Labs on five continents are upgrading their storage-ring synchrotrons and free-electron lasers to make their X-ray beams brighter and more adaptable to scientific and medical applications.Synchrotron light is now produced by storage rings and other specialized particle accelerators, typically accelerating electrons. Once the high-energy electron beam has been generated, it is directed into auxiliary components such as bending magnets and insertion devices in storage rings and free electron lasers. These supply the strong magnetic fields perpendicular to the beam which are needed to convert high energy electrons into photons. BeamlinesAt a synchrotron facility, electrons are usually accelerated by a synchrotron, and then injected into a storage ring, in which they circulate, producing synchrotron radiation, but without gaining further energy. The radiation is projected at a tangent to the electron storage ring and captured by beamlines. These beamlines may originate at bending magnets, which mark the corners of the storage ring; or insertion devices, which are located in the straight sections of the storage ring.  Undulator These magnetic structures, made up of a complex array of small magnets, force the electrons to follow an undulating, or wavy, trajectory. The radiation emitted at each consecutive bend overlaps and interferes with that from other bends. This generates a much more focused, or brilliant, beam of radiation than that generated by a single magnet. Also, the photons emitted are concentrated at certain energies (called the fundamental and harmonics). The gap between the rows of magnets can be changed to fine-tune the wavelength of the X-rays in the beam.

What is IMDS? IMDS: International Material Data System, which is a third-party organization for material composition approval. IMDS is a database system for parts and materials in the automotive industry. It was jointly developed by the automobile manufacturing companies Audi, BMW, Daimler-Chrysler, Ford, Opel, Porsche, Volkswagen and Sweden's Volvo Car Group.  What is MSDS? MSDS, Material Safety Data Sheet, namely Material Safety Data Sheet/Material Safety Instructions. Provide information on the hazards of chemicals to protect the users of chemical products; ensure safe operation and provide technical information for the formulation of safe operating procedures for hazardous chemicals; provide technical information that is helpful for emergency rescue and emergency handling of accidents; guide the safe production of chemicals, Safe circulation and safe use; It is an important basis and information source for chemical registration management.   Applicable objects:   1. Regarding the substances in the classification of dangerous goods in various countries, although the regulations of each country are different, they are usually the following 9 categories of dangerous goods:   Category 1 Explosives   Category 2 compressed gas and liquefied gas   Class 3 Flammable liquid   Class 4 Flammable solids, spontaneous combustion materials and flammable materials when wet   Class 5 Oxidizing agents and organic peroxides   Category 6 Poisonous and infectious substances   Category 7 radioactive materials   Category 8 Corrosive products   Category 9 Miscellaneous   2. Non-hazardous single substance or mixture: The most common ones are plastic products, hardware products, and packaging materials. What is SDS? SDS: Safety Data Sheet, namely Safety Data Sheet/Safety Instructions. The REACH Regulation (Directive Number: EC 1907/2006) stipulates the content of SDS in Appendix II, which was amended by Directive 453/2010 in May 2010.   The main content includes chemical and company information, hazard identification, ingredient information, first aid measures, fire protection measures, leakage measures, handling and storage, exposure control, physical and chemical properties, toxicology information, ecotoxicology information, waste disposal measures, transportation information, Regulatory information and other information 16 parts.   Applicable objects: 1. Refer to regulations 67/548/EEC or 1999/45/EC classified hazardous substances or substances in PBT/vPvB or SVHC.   2. A mixture that is not classified as a dangerous product, but contains a non-gas material with a weight percentage 1% and a gas with a volume percentage 0.2%, a substance that is harmful to human health or the environment.   3. Solid or liquid mixtures that are not classified as dangerous goods (such as non-gas mixtures), but contain ≥0.1% by weight of a substance in PBT or vPvB or SVHC

Waste-to-energy plants use household garbage as a fuel for generating power, much like other power stations use coal, oil or natural gas.Regarding garbage incineration, the first thing to note is that not all garbage can be burned. In general, garbage incineration is the burning of organic components in waste. For example, municipal solid waste represented by various domestic wastes including kitchen waste can kill toxic and harmful components through incineration, and greatly reduce the volume of waste. It can also be used, and the landfill after burning saves space. The calorific value released during combustion can also be used to generate electricity and heat, and become a waste-to-energy source. The biggest concern of environmentalists and the public about waste incineration comes from the emission of toxic substances such as dioxins and furans during the incineration process. In the last century, the old-fashioned incinerators of various countries did not pass the gas purification technology, and this problem did exist. Since the end of the last century, many countries have improved gas purification technology and hardware, and the situation has improved greatly.  Waste-to-Energy: How It WorksWaste material is received in an enclosed receiving area, where it is thoroughly mixed in preparation for combustion.The mixed waste enters the combustion chamber through the grate that moves regularly, and the grate splashes and burns at the same time.The particles in the air are removed in the filter bag.The acidic combustion gas is neutralized by injecting lime or sodium hydroxide.Acid combustion gas injection lime or sodium hydroxide to neutralize. The unburned residue from the combustion is removed by magnets and eddy current separators to remove iron and other metals such as copper, brass, nickel and aluminum for recycling.The unburned residue from the combustion is removed by magnets and eddy current separators to remove iron and other metals such as copper, brass, nickel and aluminum for recycling.Combustion of unburned residues, remove iron and other metals, such as copper, brass, nickel and aluminum by a magnet and the vortex separator for recycling.The remaining ash can be used as aggregate for roadbeds and railway embankments. Superheated steam powers the steam turbine generator. The cooling steam is cycled back into water through the condensor or diverted as a heat source for buildings or industry. Cooled stream is reheated in the economiser and superheater to complete the steam cycle.

13.8 billion years ago, shortly after the Big Bang, the universe expanded rapidly and a large amount of energy was converted into matter.Physicists speculate that this process initially produced equal amounts of matter and antimatter, which would be annihilated once they contacted.But then an unknown event was sent, making matter more than antimatter, and then forming all the things we can see and touch.Studies have shown that the clues of the event may be hidden in tiny ripples in time and space.But in fact, the universe has evolved for tens of billions of years and continues to exist today. Obviously, not all matter was annihilated at the beginning. The answer to this question may also involve a very strange elementary particle-neutrinos.The neutrino is not charged, and its antiparticle may be itself.One view is that about 1 million years after the Big Bang, the universe underwent a phase change as it cooled.Droll said: "This disguise may cause neutrinos to produce slightly more matter than antimatter when decayed. But there is no easy way to verify whether this event has actually happened in the universe. But the Droll team found a way through modeling and calculations that might be able to show us this disguised process. They proposed that the phase transition may produce an extremely slender energy line, which is still permeating the universe to this day.These cosmic rays are very likely to cause tiny ripples in space and time, that is, gravitational waves.As long as the corresponding gravitational waves are detected, the correctness of this theory can be verified.

IPPC is an international convention. The IPPC logo on the wooden packaging means that it has been treated and qualified in accordance with the regulations and does not carry harmful organisms.They developed a standard for wood packaging in international business, called ISPM-15.It looks like this:                               What is covered by this global standard?Some wood packaging production processes have reached the conditions of pesticide treatment, no longer need to carry out special pesticide treatment.For example, wooden cases and wooden pallets made entirely of plywood, particleboard, fiberboard and other artificial panels.Or made entirely of thin board (including wood shavings, wood chips, etc.) with a thickness less than 6mm.     Wood packaging processed in the production process, such as wine barrels, wooden gift boxes, etc,They also don't need to be fumigated。  In addition to the above, all wood packaging containing solid wood components must be treated in accordance with the regulations, and the standard IPPC mark, such as the following wood package:    How to add the IPPC mark to the wooden case of goods?Only with the enterprises that have obtained the customs permission to apply the label on the wooden packaging of outbound goods can produce and apply the IPPC mark on the wooden package of outbound goods.The enterprises using wood packaging can purchase wood packaging from the qualified labeling and applying enterprises, and require the labeling and applying enterprises to provide the certificate of qualified wood packaging disinfection and disinfestation treatment for outbound goods.Improper handling of inbound and outbound wood packaging may lead to the spread, diffusion and colonization of pests during international transportation.If the exported goods are packaged in natural wood packaging, IPPC should be added according to the destination country of the export. For example, if the packaged goods exported to the European Union, the United States, Canada, Japan, Australia and other countries are packaged in conifer wood, they must be fumigated.For fumigation, it is now standardized that the fumigation team will fumigate the container according to the container number, that is, after the goods arrive at the site, the professional fumigation team will stamp the IPPC mark on the package.

Magnetic Particle TestingMagnetic particle inspection is also known as MT or MPT, which is suitable for inspection methods near the surface of magnetic materials such as steel.Use the principle that iron is attracted by magnets for inspection.During the magnetic particle inspection, the object to be tested receives the action of magnetic force, and the magnetic powder (magnetic micro powder) is scattered on its surface.Then, the leaking magnetic force leaking out of the defective part of the surface will attract the magnetic powder to form an indication pattern. The indicator pattern is dozens of times larger than the actual defect, so it is easy to find the defect.Magnetic particles are applied to the surface of the specimen. The specimen is then magnetised. If flaws are present the magnetic particles form anarrangement around the fault. This method is used on magnetic materials such as steels and cast irons. Magnetic particles can detect defects up to 18 mm below the surface of a weld.Magnetic particle inspection method1，Pre-treatmentIf grease, paint, rust, or other foreign matter adheres to the flaw detection surface, it will not only prevent the magnetic powder from being adsorbed on the scar, but also cause the magnetic powder to adsorb to the part other than the scar to form a suspicious image.Therefore, before magnetization, a physical or chemical treatment is used to remove dirt and foreign matter.2，MagnetizationIt is very important to magnetize the test object properly.Usually, a magnetization method perpendicular to the direction of the scar and the direction of the magnetic force line is used.In addition, for proper magnetization, various methods can be used according to the shape of the object to be detected.3，Use of magnetic powderIn order for the magnetic powder to be adsorbed between the magnetic poles of the scar to form a detected image, the magnetic powder used must be easily magnetized by the weak magnetic field of the scar and adsorb to the magnetic poles, that is, a certain adsorption performance is required.In addition, it is required that the magnetic powder image formed must have a high degree of recognition.Generally, the magnetic powder used in magnetic particle inspection includes white, black, red and other different magnetic powders used under visible light, and fluorescent magnetic powders that use fluorescent light.In addition, depending on where the magnetic powder is used, there are powdery dry magnetic powder and wet magnetic powder dispersed in water or oil.4，ObservationTo observe the magnetic particle image attached to the scar, it is necessary to create an easy-to-observe environment.Ordinary magnetic powder needs to be observed in the brightest possible environment, while fluorescent magnetic powder needs to use ultraviolet light to make the surroundings as dark as possible to be easy to observe.

Sintered NdFeB, as the name implies, is an alloy material composed of Nd2Fe14B, a compound composed of three elements: Nd, Fe, and B. However, sintered NdFeB is not a single phase. It consists of Nd2Fe14B phase and B-rich phase (also known as Nd1 .1Fe4B4 phase) and Nd-rich phase (also known as rare-earth-rich phase), of which the Nd2Fe14B phase is the main phase or basic term. Most rare earth elements (RE) form RE 2Fe14B compounds, which are the basic phase of sintered rare earth iron boron permanent magnet materials, accounting for 96%-98% of sintered rare earth iron boron permanent magnets. All RE 2Fe14B compounds have the same crystal structure, but their magnetic properties are very different. Adding other rare earth elements to sintered NdFeB to replace neodymium can change some properties of the magnet. The role of heavy rare earth metal Dy instead of Nd 1. Significantly improve the coercivity of the magnet The anisotropy field HA of Dy 2Fe14B compound is about 2.14 times higher than that of Nd2Fe14B, so replacing Nd with a small amount of Dy can significantly increase the coercive force Hcj of the magnet. Theoretically, every time 1% (atomic fraction) Dy replaces Nd, the coercive force Hcj of the magnet can be increased by 11.4kA/m, but the increase in coercive force Hcj in practical applications is related to the existence of other components. 2. Reduce the magnetic polarization intensity Js of the magnet Thereby reducing the remanence Br and the maximum magnetic energy product (BH) m In theory, every time 1% (atomic fraction) Dy replaces Nd, the magnet's magnetic polarization intensity Js decreases by 90mT 3. Reduce the temperature coefficient of magnet remanence Br and maximum magnetic energy product (BH) m It should be noted that the addition of heavy rare earth element Dy will significantly increase the raw material cost of sintered NdFeB permanent magnets, so the relationship between cost and magnet performance needs to be comprehensively considered. The role of heavy rare earth metal Tb instead of Nd Adding Tb to the sintered NdFeB magnet to partially replace Nd has the same effect as the replacement of Nd by Dy, but the anisotropic field HA of Tb 2Fe14B is higher, so it can more effectively improve the coercivity of the permanent magnet. But Tb has less reserves in rare earth mines than Dy, and the price is higher. The role of metal Gd and metal Ho replacing Nd Among the heavy rare earth metals, Gd has the highest reserves, and Gd can also form Gd2Fe14B compounds. The magnetic polarization intensity Js and anisotropic field HA of this compound are obviously lower, but its Curie temperature Tc is the highest. Due to the high reserves of Gd and the low price, some manufacturers add Gd in the form of gadolinium-iron alloy to partially replace Nd to produce low-cost sintered NdFeB. However, its practical use of Gd to replace Nd is a waste. Once it is discovered that Gd has more important uses in the future, it will be found to be an irreversible loss. Replacing Nd with Ho has the same effect and problem. The role of light rare earth metals La, Ce, Pr instead of Nd The reserves of light rare earth elements are abundant and the price is relatively cheap. The development of light rare earth metals for the manufacture of sintered NdFeB materials is worth encouraging. La, Fe, and B metals are difficult to form La2Fe14B, and the temperature is very narrow, but once formed, it is stable below 860°C. Nd accounts for 65%-75% of the cost of sintered NdFeB. At this stage, the cost of La is about one-tenth of Nd. Substituting La for Nd can reduce costs and promote the comprehensive utilization of rare earth resources. With the increase of La content, the magnetic polarization intensity Js, remanence Br, coercive force Hcj and maximum magnetic energy product (BH) m of the alloy will all decrease. La is a non-magnetic atom. Because of magnetic dilution, (BH)m decreases It decreases much faster than Br. Ce2Fe14B has poor stability and is more difficult to form. With the increase of Ce content, various magnetic properties are reduced. At the same time, the addition of Ce will cause the Curie temperature and temperature stability of the magnet to decrease. The Pr2Fe14B compound has several basic conditions that can be used as a permanent magnetic material. It can be sintered at about 1060°C to obtain better magnetic properties. Using (PrNd)-Fe metal as a raw material can produce sintered NdFeB permanent magnets with good magnetic properties. It should be noted that Pr is easier to oxidize than Nd, and the amount of Pr must be appropriately controlled for some materials that require high stability. The role of other metals replacing Fe The low coercivity and Curie temperature of sintered NdFeB permanent magnet material, poor temperature stability, low working temperature (about 80℃), poor corrosion resistance and other shortcomings limit its application range. For this reason, people the effects of various elements on NdFeB permanent magnet materials have been extensively studied. 1. The effect of cobalt-Co partial substitution of Fe on sintered NdFeB With the increase of Co content, the Curie temperature of the alloy increases linearly, and the reversible temperature coefficient of magnetic induction decreases significantly. When the Co content is less than 5% (atomic fraction), (BH) m and Br hardly decrease; when the Co content is more than 30%, the magnetic performance parameters are significantly reduced. The added Co content of less than 10% is very beneficial, which not only increases the Curie temperature of the alloy, but also maintains higher magnetic properties, and at the same time the temperature coefficient of magnetic induction is also improved. 2. The role of Al partly replacing Fe The research results of scholars show that adding a small amount of aluminum Al can significantly increase the coercivity of the ternary Nd-Fe-B material. The research results point out that since the Nd-Fe-Co-B permanent magnet material, the addition of Al can compensate for the decrease in coercivity caused by the addition of Co, so that a Nd-Fe-Co-Al- with higher comprehensive performance can be obtained. B alloy. 3. The role of Cu partially replacing Fe pair Studies have found that adding a small amount of copper to the (Nd, Dy)-Fe-B and (Nd, Dy)- (Fe, Co)-B systems can significantly increase the coercivity, while Br hardly decreases, so that permanent magnets with high Hcj and high (BH)m can be manufactured. 4. Partial replacement of Fe by other elements Based on ternary Nd-Fe-B alloy, adding a small amount of niobium Nb or zirconium Zr to replace part of the iron can effectively increase the Hcj and squareness Hk of the alloy, while the Br is reduced very little, and the magnetic flux of the alloy cannot be reduced. loss. The experimental results show that the maximum content of niobium and Nb in Nd-Fe-B alloy is 3% (atomic fraction), adding excessive Nb will make the coercivity of the alloy drop rapidly and make Nd2Fe14B unstable The addition of gallium Ga can significantly increase the coercivity of the alloy and reduce the irreversible magnetic field. In the Nd-Fe-Co-B series alloy, as the content of Co increases, the Hcj of the alloy decreases, but when Ga is added Bottom, the coercivity increased. It is expected that it is possible to prepare Nd-Fe-B permanent magnet materials with high Curie point and high Hcj in alloys with Ga added The compound addition of gallium Ga and niobium Nb can significantly improve the temperature stability of the alloy. Dy Ga Ho La

Is wireless charging safe? It is very safe to contact the wireless charger closely. When your smart phone is actually in contact with the charging base, the signal will be concentrated to the receiving coil of the mobile phone, thus starting charging. Compared with the mobile phone connected to the mobile network, the radiation emitted by the entire wireless charging process is much smaller. Will the wireless charger get hot? During the charging process, all chargers will generate a certain amount of heat. Indoor chargers, charging bases and even portable power banks will lose a certain amount of energy in the form of heat. Wireless chargers are no exception. Is it safe to overcharge the smartphone? Most charging pads will use trickle mode to safely charge the mobile phone battery to ensure that the mobile phone battery is always fully charged, so it is safe to leave the mobile phone on the charging pad overnight and even longer. Trickle charging refers to: when the mobile phone is placed on the charging board, if the battery charge falls below 100%, a small amount of current will be provided to the battery to ensure that it is always fully charged. Electrical Surge Although your charging pad or charging base is connected to a wall outlet, the socket may be affected by lightning strikes and other electrical surges, but the wireless charger will not pass the increased voltage to your smartphone. Therefore, wireless charging is safer than using a power outlet to charge a smartphone. What if there is a foreign material on the wireless charger? Maybe keys or coins. These may cause the charging pad to continue to discharge, which will not only damage your device, but may also melt foreign material on the charging pad. Therefore, it is very important to find a charger equipped with a foreign object detection device. Once a foreign object is found, an alarm will sound-usually with an LED light, indicating that a foreign object other than a compatible device has touched the charger. This will help prevent charging hazards.

1. What is powder metallurgy? Powder metallurgy is a technology that manufactures metal powder, and uses metal powder (sometimes also adding a small amount of non-metallic powder) as a raw material to produce materials or products through mixing, forming, and sintering. It includes two parts. (1) Manufacturing metal powder (also including alloy powder, hereinafter collectively referred to as "metal powder"). (2) Using metal powder (sometimes also adding a small amount of non-metallic powder) as a raw material, after mixing, forming and sintering, manufacturing materials (called "powder metallurgy materials") or products (called "powder metallurgy products"). 2. The prominent advantages of powder metallurgy. (1) Able to manufacture materials and products that cannot be manufactured or are difficult to manufacture using other processes, such as porous, sweating, shock absorption, sound insulation and other materials and products, refractory metal materials and products such as tungsten, molybdenum, titanium, metal-plastic, Bimetallic composite materials and products. (2) It can directly manufacture products that meet or approach the size requirements of the finished product, thereby reducing or eliminating mechanical processing. The material utilization rate can be as high as 95% or more. It can also replace copper with iron in some products, which achieves "saving materials." , Energy saving ". 3. What is the particle size range of the powder? Powder size range refers to the size of powder particles that vary between two specified sizes.If the particle size range of a powder is -80 + 150 mesh, it means that the particle size of these powders is equal to or less than 80 mesh and greater than 150 mesh. In other words, these powders passed the 80 mesh sieve, but not the 150 mesh sieve. 4. What are the special powder forming methods? (1) Isostatic pressing; (2) Continuous forming; (3) Pressureless forming; (4) High energy forming; (5) Injection forming.