News & Events
Using artificial diamonds can break the classical laws of thermodynamics and humans are taking an important step towards finding the limit
According to a report in the proceedings of China on December 5, the quantum physicists are using artificial diamond experiment, trying to prove that a few years ago has just been theorized effect: quantum drive can make the diamond power output is higher than the classical thermodynamic limit level.
Only reckless physicists dare to break the laws of thermodynamics. But, as it turns out, there may be ways to change these laws. In a laboratory at Oxford University in England, quantum physicists are trying to do this with a small piece of synthetic diamonds. At first, the diamond was almost invisible in the tangle of optical fibers and mirrors. However, when the researchers opened the green laser, the defects in the diamond were illuminated and the crystals began to glow red.
In this light, scientists have found preliminary evidence of a theoretical effect a few years ago: a quantum boost that gives diamonds more power than classical thermodynamic limits. If found, they will bring tangible benefits to quantum thermodynamic research. Quantum thermodynamics is a relatively new field that aims at revealing the laws governing heat and energy flow on an atomic scale.
Break the law
The development of classical thermodynamics goes back to the 19th century. They were born to understand the efforts of the steam engine and other macro-systems. Thermodynamic variables such as temperature and heat are statistically significant and are defined according to the average motion of large particle groups. But back in the 1980s, an early pioneer in the field, Ronnie Kosloff, a researcher at the Hebrew university of Israel, began to wonder if the situation would still work for a small number of systems.
Kosloff said it was not a popular research branch at the time, because most of the questions to answer were abstract, and the hopes of combining trials were slim. "The field is developing very slowly." "I've been alone for years," says Kosloff.
This has changed dramatically about a decade ago, as questions about the miniaturization of technology became increasingly urgent and experimental technology breakthroughs. The researchers conducted a series of attempts to infer how thermodynamics and quantum theory were combined. However, Kosloff said that the resulting proposals created more confusion than the problem became clearer. Some claim that quantum components can break classical thermodynamic limits without damage, so they can work as a perpetual motion machine without any energy input. Others have argued that the laws of thermodynamics should remain unchanged at very small scales. But they are equally perplexed. "In some cases, you can infer the performance of a single atomic engine and a car engine using the same equation." Kosloff said, "but it also looks shocking -- to be sure, when objects get more and more hours, they should reach some quantum limit." In classical thermodynamics, individual particles have no temperature. Therefore, the university of freiburg, Germany quantum physicists Tobias Schaetz believes that as the work of the system and its environment approaching a limit, imagine they will obey the rules of the standard thermodynamic increasingly become a ridiculous thing.
To find the limit
Inspired by the idea that information is a physical quantity and closely related to thermodynamics, researchers have tried to rewrite the laws of thermodynamics so that they can work in quantum fields.
Perpetual motion seems unlikely. The early hope, though, is that the quantum thermodynamic constraints may be less stringent than in classical fields. "This is a series of ideas that we've learned from quantum computing, that quantum effects help break classical boundaries." "Said Raam Uzdin, a quantum physicist at the Israel institute of technology.
He also said it was disappointing that this was not the case. Organize new analysis shows that the second law of (efficiency) and the third law (ban system achieve absolute zero) and traditional quantum version of "avatar" keep similar restrictions, in some cases even more stringent restrictions.
The theory also reveals some potential leeway. In a probe of information flow in a particle moving between hot chamber and cold chamber theory analysis, including a photon science institute (Barcelona, Spain quantum physicist Arnau Riera and Manabendra Nath Bera, the team found a strange scene: room seems to spontaneously become more hot, and cold chamber becomes colder. "At first it looked crazy, like we broke the laws of thermodynamics." Bera said. But researchers quickly realized that they ignored the quantum distortion that particles in the chamber became entangled with each other. Theoretically, generating and breaking these associations provides a way to store and release energy. Once such quantum resources are included, the laws of thermodynamics are emerging.
Some independent teams propose to use such entanglements to store energy in "quantum batteries". Meanwhile, a team from the Italian institute of technology is trying to identify the predictions of the Barcelona team using a battery built from a superconducting quantum bit. In principle, such quantum batteries can be charged much faster than conventional batteries. "You can't extract and store energy beyond the traditional limits of allow-this is determined by the second law." "But you may be able to speed up the extraction and storage of energy," Riera said.
Some researchers are looking for simpler ways to manipulate bits of quantum computing applications. By manipulating the energy levels of quantum bits, the quantum physicist Nayeli Azucena Rodriguez and his colleagues at the university of Waterloo in Canada have devised a way to enhance the cooling capacity of quantum computing operations. They are now planning to test the idea in a laboratory using superconducting quantum bits.
Take an important step
The concept of quantum effects that can be used to improve thermodynamic properties is also an inspiration for the diamond experiment at Oxford University. The trial was first proposed by Kosloff, Uzdin and Amikam Levy, who works with Hebrew university. Founded by a nitrogen atom in diamond can act as the engine of defects - this is a first with high temperature heat source (laser) in the experiment, and then after contact with low temperature heat source can perform operation of machines. But Kosloff and his colleagues hope to use the quantum effects that make some electrons exist at the same time in two energy states, and that such engines can operate in enhanced mode. By firing laser pulses instead of using continuous beams to maintain these superpositions, they should be able to release the microwave photons more rapidly.
Recently, the Oxford University team released a preliminary analysis and presented evidence of the existence of a predicted quantum boost. While the paper has not yet received peer review, Janet Anders, a quantum physicist at the university of Exeter, said it would be "a breakthrough" if the work was tenable. However, Anders said it was unclear what made the "feat" possible. "It looks like a magical fuel that doesn't have to add much energy, but it makes the engine extract the energy more quickly." "Theoretical physicists still need to study how it does that," Anders said.
In the view of Peter Hanggi, a quantum physicist at the university of augsburg, the focus test is just a significant step in the right direction in the process of reviving the field. But for him, the tests were not bold enough to give real breakthrough insights. At the same time, there is a challenge to ignore: measurement operations and interaction with the environment can create irreversible interference with quantum systems. These effects are rarely fully taken into account in the theoretical recommendations for new trials, Hanggi said. "It's hard to calculate, it's harder to implement in the experiment."
Ian Walmsley of Oxford University, who led the diamond trial, is also cautious about the future of the field. Although Walmsley and other experimenters have been drawn to quantum thermodynamic research in recent years, he says their interest is largely "opportunistic". They found the opportunity to develop relatively fast and simple tests, using devices that had already been installed for other purposes. For example, the diamond defect test device has been widely used in quantum computing and sensor applications. Walmsley believes that quantum thermodynamics is booming. "But it remains to be seen whether it will continue to be active, or ultimately, nothing."
The BMO expects cobalt prices to rise again by 2019 or up to $40.50 a pound
According to BMO Capital Markets, according to data with the surge in demand growth, cobalt supply has been very nervous, the price has reached the highest level in ten years, and may double in the next few years.
"There is no question of doubling the spot price of cobalt in the coming years," BMO said in an investment report on Monday. Even without the need for electric cars, cobalt is a tight market. What's more, the penetration rate of electric vehicles is forecast to reach 10% by 2025.
The LME's cobalt price has more than doubled this year, with tesla, Volkswagen and general motors Co. planning to increase production of electric vehicles. Banks such as Exane BNP Paribas and other major producers such as glencore forecast rapid growth in battery use.
The democratic republic of Congo has more than half of the world's reserves.
The BMO forecasts a further increase in cobalt prices. To spur supply growth and encourage alternatives, cobalt prices will have to rise from around $30 a pound now to the peak of $50 a pound in 2007. The average cobalt price is expected to be $40.50 per pound by 2019.
Bloomberg New Energy Finance has also said that the booming market for electric vehicles could drive cobalt demand up to 47 times by 2030.
Industry news express
Tungsten raw material market holding firm tungsten price stable operation
Domestic tungsten city as a whole are institutions and large tungsten enterprises guided price rise, inhibition of superposition tungsten grain production, raw material market pull downstream enterprises enquiries are increasing, tungsten products steady rise of patterns in the mainstream price, market transactions to be follow up.
Overweight tungsten concentrates on the market, the environmental protection policy, the production cost is higher, and big companies attitude stability, the tungsten raw material at the bottom of the support is strong, the supplier processing enterprise for confidence, wu goods rised emotional full-bodied, black tungsten concentrates the market price is 65 degrees now to 110000 yuan/ton.
APT on the market, the upstream supply is hard to find at a lower price, cost support smelting firms with higher price, buy up downstream, under the influence of psychological first stock will also increased, however, restricted by end demand, trade type enterprise purchase intention is still weak, the market actual transaction is given priority to with just need a small amount. The supply and demand standoff, APT manufacturer to reduce the price to go goods will not be strong, short-term conservative follow up the raw material price.
Tungsten powder on the market, near the end of the market inflows less, after the end of the market to the high price raw material consumption ability is low, and the raw material supply of goods procurement difficult to follow the price rise, powder market order basically reflect on rigid clinch a deal. However, with the increase of the average price of the forecast of a new round of tungsten, the company's confidence has been supported, and the price of high grade tungsten powder is gradually close to 265 yuan/kg.
Together, the raw material of new slow spot supply, short-term price will keep steady upward trend in tungsten, but the market has not fully become a seller's market, industry participants still demand and capital direct messages need to be careful attention.
The industrial and commercial bureau of ezhou is escorting the development of diamond
With advanced technology and flexible marketing mode, the diamond tool industry in ezhou city has become the main production base of diamond tools and related products in China. The city of yanji, known as "China diamond cutter first town", its "yan cepa standard" also becomes the national standard.
In recent years, a number of illegal businessmen have made a profit on the famous diamond brands in ezhou, disrupting the business order of the diamond industry and making the city's diamond brands suffer. Infringement behavior, in the face of the diamond market appear to ezhou, industrial and commercial bureau "against infringing counterfeit enforcement action" as the gripper, crack down on fake diamond market infringement violations, as "the first town of diamond cutting tools in China" be a good keeper. As of now, there are 5 cases of diamond counterfeiting infringement cases, and the case value is 15.5 million yuan.
In order to further standardize the diamond market order, the industrial and commercial departments of ezhou combined with the development characteristics of the diamond industry, and established the system of random inspection of the sub-market subject, and implemented differential supervision. Town town of yanji, diamond industrial park the sub-centres intensify inspection, establish diamond market main body credit standing book, refining the diamond industry credit rating, increasing credit unit of missing inspection frequency, intensify supervision, strengthen their own credit construction market main body.
Brands need to be created and protected. In the "I work for business operators" activities, in conjunction with the hongxing tool factory in ezhou city, the "hongxing" trademark has been successfully used to protect the legitimate rights and interests of the operators. This year, under the guidance of the industrial and commercial department of the city of ezhou, the brand protection mechanism has been established by e xin, changli and li lai, and the investment in brand protection has been increased.
As of October, the industrial and commercial system of the city of hubei has been sent out to the law enforcement personnel by 2737 (the number of persons), and the subject of inspection is 6940 (household); In order to check the total number of customers' demands, the total number of customers' appeals was 6301, and the total number of consumers' economic losses was 248.86 million yuan. "Double dozen" cases 125 cases, the value of 114 million yuan, among them the trademark infringement case 7 pieces, the case value 130,000 yuan, created the market environment of fair competition and safe and assured consumer environment.
Liu bingbing of jilin university discovered the new monoclinic sp3 super hard carbon structure
Recently, professor bing-bing liu team to C70 confined carbon nanotubes composite structure (C70 peapod along), the use of ultra-high pressure technology won the atmospheric pressure can be intercepted, can make the diamond YaZhen indentation new carbon structure, theory combined with experimental means for further reveals the carbon phase with monoclinal structure, full sp3 superhard new carbon structure. The research will inspire people to design and utilize new materials with excellent performance in combination with high pressure technology, and provide a new way for the research and development of new multi-functional materials.
CAD design method of carbide woodworking circular saw blade
Carbide circular saw blade is an efficient cutting tool. It is widely used in cutting wood, plastic, aluminum profile, organic glass, furniture and other industries because of its narrow cutting saw, high efficiency and good cutting surface. This paper introduces the name of each part of the carbide circular saw blade, the composition structure of the saw blade and the selection of the parameters of CAD software design.
The name and description of each part of carbide circular saw blade
The carbide circular saw blade consists of the alloy knife head and the body. The body is steel plate, the material is mostly alloy tool steel, spring steel and other high quality steel plate. Owing to the fast cutting speed of saw blade in work, it produces a lot of heat. For better heat dissipation, several loose hot lines and radiation holes can be designed on the ontology. Because of the high speed during the work of saw blade, the noise is very high, which can be used according to the object of sawblade processing, and design different sound reducing channels to reduce noise pollution as much as possible. The installation hole can be designed according to the diameter of the spindle diameter and the installation method of the machine tool equipment, such as optical hole, keyway hole and small round hole. The blade is made of hard alloy and the head needs to be soldered to the body. Welding with manual welding and automatic machine welding. Carbide circular saw blade structure, as shown in FIG. 1.
2. Selection of carbide tool head
Cemented carbide is a kind of alloy material made of refractory metal and bonded metal through powder metallurgy. It is widely used in cutting tool materials due to its high hardness and wear-resisting characteristics. Hard alloy has tungsten cobalt (YG) and tungsten titanium (YT). Tungsten-cobalt hard alloy has good impact resistance and is widely used in wood processing. The commonly used models are YG8 ~ YG15, and the figure behind YG indicates the percentage of cobalt content. The impact toughness and bending strength of the alloy improved with the increase of cobalt content, but the hardness and wear resistance decreased. Therefore, the choice of the size of the blade of the blade should be selected according to the different cutting objects. For example, the cut cork can choose the larger number of the number, the blade of the cut solid wood needs high hardness to choose the small number.
3. Selection of the parameters of the ontology
- 3.1 selection of body material The 65Mn spring steel is widely used as an ontology by domestic saw blade manufacturers because of its elasticity and plasticity, quenching of heat treatment and material economy. Because it has the disadvantage of low temperature and easy deformation, it is used for cutting. 50 mn2v alloy steels, due to its added 0.08% ~ 0.16% of vanadium, improve the quenching properties, while increasing the manganese content, reduces the carbon content, improved the various mechanical and mechanical properties of steel, improves the heat resistance, heat distortion temperature in 300 ~ 400 ℃, extend the service life of the saw blade. This material is suitable for making high-grade carbide circular saw blades. In China, there are 45Mn2V and 50Mn2V, and the Japanese saw blade ontology is SKS5.
- 3.2 selection of body thickness The thickness of the saw blade determines the width of the blade, and the width of the blade is generally about 1mm larger than the size of the body thickness. Although the thickness of the body is thicker the higher the strength, the width of the blade will also increase correspondingly, resulting in the width of the saw and the increase of material consumption. The thickness of the alloy saw blade is determined by the material of the sawblade body and the process of making the saw blade. The thickness of the blade is too thin and the blade is easy to swing when working, affecting the quality of the cutting. The selection of blade thickness should consider the stability of its work and save the cutting materials, while some saw blade thickness is specific, such as slotting saw blade, marking saw blade, etc.
- 3.3 selection of body diameter The diameter of saw blade is related to the thickness and equipment of the cut piece. When the blade thickness is certain, the smaller the diameter, the higher the strength. According to the thickness of the processed objects, the diameter of the saw blade is 110, 150, 180, 200, 205, 250, 255, 300, 305, 350, 355, 400, 500 (unit: mm). The diameter of the sawing trough of precision cutting board is 120mm.
- 3.4 determination of tooth number The teeth of the saw blade are determined by the cutting object and the cutting method, usually the tooth spacing is 15 ~ 25mm. For example, the cutting materials are dense and hard, and the number of teeth is more. On the contrary, the cutting material is loose, the chip is larger, and the number of teeth is reduced correspondingly. Cutting the same wood, the longitudinal cut and the crosscutting manner are different, the number of teeth is also different. The longitudinal cutting materials are sparse and the teeth are few. Cross cut material fiber more, the tooth number is much. Of course, the amount of hard alloy blade will increase, and the price of saw blade will increase, so there are more factors to be considered.
- 3.5 blade profile selection Some forms of common saw blade profile are shown in FIG. 2. Flat tooth grinding is simpler and less costly, mainly used for sawing of common wood, or used for slotting saw blade to keep the bottom level. The shape of the left and right tooth is the most widely used, the cutting speed is fast and the grinding is simpler, which can be used for multiple saws, solid wood, edge saws, reinforced flooring and aluminum alloy veneers. The left and right flank profile is used for plywood, frame and particleboard. The trimmings are more complicated, which can reduce the surface collapse and prevent the adhesion and sawing of the aluminum alloy, usually used for cutting board saw and aluminum alloy. Due to the larger diameter and thickness of the electronic drive saw, the average diameter is 350 ~ 450mm, and the thickness is between 4.0 and 4.8mm.
- 3.6 blade Angle design of saw blade There are six cutting edges of saw blades, radial front Angle, radial rear Angle, transverse front Angle, apex inclination Angle, side rear Angle and side Angle. Among them, the most influence on cutting performance is radial front Angle and radial back Angle. Radial rake Angle, the greater the sharpness, the better, the faster the cutting speed, is in commonly 10 ° ~ 20 °. When the processing materials are soft or solid wood, the radial front Angle should be larger; On the other hand, the texture is slightly smaller. The radial posterior Angle is used to prevent the friction between the sawtooth and the processed surface. The larger the rear Angle, the smaller the friction and the more smooth the processed products. But the radial front Angle must be, the larger the radial Angle, the thinner the blade will be, resulting in lower strength. Carbide saw blade radial Angle after general values in 10 ° ~ 15 °.
- 3.7 the design of the hotline The hotline is designed to quickly dissipate the blades during processing. If it does not heat up in time, the saw blade will become deformed, which will affect the cutting quality of the saw blade, which will cause the machining to fail normally. The dispersion hotline is composed of a smooth curve, which is cut directly by the laser. The ends are small round holes or elliptical holes with a diameter of about 0.5mm. Figure 4 shows the shape of the common scattered hotlines. The number of loose lines is generally determined by the size of the saw blade and the number of blades. Most of the sawblade bodies with diameters of 300mm or over 300mm are used in a long line, and the number of designs is a multiple of the number of blades, generally 3 ~ 5. A multi-slice saw or thin blade saw is not very large in diameter, it is not recommended to use a loose hot line, mostly designed as a cooling hole.
- 3.8 the design of the muting groove When cutting at high speed, the blade produces noise pollution. The noise above 90dB can affect the hearing, so it is necessary to use the muting groove structure to reduce the noise when designing the saw blade. The three structures of the muting tank are shown in figure 5. The multi - blade saws are mostly used in the B - image muting tank, and A diagram of the muting channel is adopted for more than 250mm diameter. If a purple copper rod is embedded in the muffler, such as a C diagram, it is better to reduce the noise and is generally used in a large diameter saw blade. The length of the muting tank is determined by the diameter of the saw blade, and the length of the blade of the small diameter saw blade is short. The length of the large muting slot of the saw blade is long
- 3.9 type and size of mounting hole The center hole of the saw blade is the mounting hole of the saw blade. The diameter of the blade is directly related to the thickness of the installation shaft of the woodworking sawing machine. Be sure to ask the customer for the size of the hole when designing the hole. The mounting hole is in the form of a bare hole with a rectangular keyway mounting hole (with one or two keyways) and mounting holes with small round holes (one or two round holes). At present, the diameter of the blade diameter of the saw blade in domestic design is 20mm in diameter, and the diameter of the blade diameter is 20mm. The diameter of the saw blade is 25.4mm mounting hole at the diameter of 120 ~ 230mm; The diameter of the saw blade is 30mm above the 250mm diameter. Some imported equipment also has a 15.875mm mounting hole. The multi-blade saw mounting holes usually have key grooves to ensure their stability.
- 4 saw blade CAD design method The design process of carbide woodworking circular saw blade is based on the parameters mentioned above. First draw the horizontal and vertical center line, draw the diameter of the blade to draw the circle and the circle where the hole is located. Secondly, select the suitable carbide tool head, select the radial front Angle and the radial back Angle according to the different materials, and draw the outline of the blade and the base of the tooth with the Angle line. Redraw the tooth groove and the back of the tooth. The difference between the diameter of the blade and the diameter of the blade is generally around 3mm. The length of the head is about 1.5mm, and the blade cannot be hung too much. It can not be hung too little, otherwise it is easy to hit the body. 1.1.5mm by deviation command. Use the round array command array to give all the teeth of the saw blade according to the number of blades. Then draw the circle of the diameter of the slot. The diameter of the circle is related to the spacing of the body teeth, and the distance of the tooth space is a, and the depth of the tooth groove of the tooth groove is shown in table 3, and the circular deviation of the body diameter is the circle of the diameter of the tooth groove. Saw blade tooth spacing of ontology a tooth groove depth and ontology h relationship by tooth back slash depends on the size of radial rake Angle, the general will tooth line copy after spinning around 15 ° as tooth arch wire, figure 6 for tooth and tooth groove. The slot of the tooth groove is to capture the base line of the teeth, the round of the tooth groove and the anticlinal line of the tooth, and make the appropriate adjustment, so that the area of the tooth groove and the tooth base is roughly the same. Remove redundant lines, and only retain a complete tooth base, tooth groove, tooth back and alloy blade profile. Once again, using the circular array command to complete the profile of the tooth profile, and based on the muffler and the loose hot line parameters, design and draw the muffler and the loose hot line. Finally fill in the title bar and complete the design requirement of the saw blade. FIG. 7 is the name of the parts of the carbide woodworking circular saw blade.
- Carbide woodworking circular saw blade with CAD software design, according to the cutting environment and objects, first needed to master the saw blade size, the tooth profile, such as installation size of holes, and then specific to each blade parameters, the optimized adjustment, design a suitable qualified saw blade cutting requirements.