With the release date of the iPhone 8 approaching, the discussion about wireless charging technology is becoming more and more popular.
We usually think that electricity and magnetism are related, so when discussing the principle of wireless charging, most of them are based on the phenomenon of electromagnetic induction or derived from it. At present, there are mainly four ways to achieve wireless power transmission:
Magnetic field induction
The primary coil is given a certain frequency of AC, which generates a certain current in the secondary coil by electromagnetic induction, thus transferring energy from the transmission end to the receiving end. This principle is similar to the transformer principle commonly used in power system. When the primary coil of the transformer is fed with alternating current, the secondary coil will induce the electromotive force due to the principle of electromagnetic induction. If the secondary circuit is connected, the induced current will appear, so that the electric energy can be realized from the transmitting coil to the receiving line. The wireless transmission of the ring. At present, this way of transmitting electric energy has been widely used in the wireless charging market of small power and short distance, such as small portable electronic devices such as electric toothbrushes, mobile phones, cameras, etc., which are generally charged by the charging base. The power transmitting coil is installed in the charging base, and the receiving coil is installed in the electronic device.
Resonance
The principle of wireless transmission is similar to that of wireless communication. The electromagnetic wave of the resonant circuit at the transmitter is omnidirectional and open throughout the space, and the resonant circuit at the receiver is resonated at the specific frequency to realize energy transmission. This transmission mode can achieve higher transmission efficiency when the receiver's output power is small. But the existence of electromagnetic radiation, the greater the transmission power, the farther the distance, the lower the efficiency, the more serious the radiation.
Magnetic coupling resonance
This method can be seen as a resonant enhanced version. It needs to transmit and receive two resonant systems, which can be made of induction coils respectively. By adjusting the transmitting frequency to make the transmitter vibrate at a certain frequency, it produces a non-radiating magnetic field instead of the ordinary electromagnetic wave which is diffused everywhere. That is, it converts electric energy into magnetic field and forms an energy channel between the two coils. The natural frequency of the receiving terminal is the same as that of the transmitting terminal, resulting in resonance. With each resonance, there will be more voltage in the receiving terminal inductor. After multiple resonances, the surface of the inductor will gather enough energy, so that the receiving end receives energy in this non-radiating magnetic field, thus completing the conversion of magnetic energy to electric energy and realizing the wireless transmission of electric energy. In 2008, a MIT laboratory demonstrated an experiment in which a 60W light bulb was lit in a two-meter gap. They named the technology Witricity, and the project is still in the laboratory stage. Of course, the range of this non-radiated electromagnetic field is relatively limited, and it is not suitable for long distance. It requires that the transmitter and the receiver be within 8 times the radius of the induction coil.
Radio waves
We all know that electromagnetic waves can be used to transmit information, so theoretically, as long as the frequency is high enough, energy can also be transmitted. This wireless charging method is probably the closest to what people imagine wireless charging. An electromagnetic wave generator is installed at the power source, then energy is transmitted to the receiving antenna through the transmitting antenna, and then the electromagnetic wave signal is converted into electrical energy for equipment use. But this power transmission mode also has obvious weaknesses, such as large interference of electromagnetic wave, low transmission efficiency, radiation to human body and so on.
There have been anecdotal reports that although Apple has joined the Wireless Power Consortium, the official response has been ambiguous about whether Apple will implement QI standards for wireless charging technology. At present, the wireless charging power of QI standard is mainly maintained at about 15W. It is speculated that the wireless charging power of the iPhone 8 will use 5V/1.5A, while 7.5W charging power may take a whole night to fill a mobile phone. Therefore, at present, long-distance transmission in a small scope is not yet mature at the technical level.
We expect scientists and engineers to make breakthroughs and bring us more surprises in the future.
The development of digital screen abroad is very mature, but it is still in the introduction stage in China.
Digital screen is a new product that changes the computer usage mode and revolutionizes the office environment. It can completely change the traditional computer usage mode of display + mouse + keyboard. Digital screen integrates LED display and digital board. Users can use their matching pressure pen to input directly on the LCD screen, including handwriting and painting. In addition to the non-radiation and space-saving features of the LED LCD screen, the digital screen can also directly write screen input, and the feeling of writing is the same as that on ordinary paper. As a high-end computer input and output device, digital screen can make office environment more concise and fashionable. Because of its intuitive and efficient input mode, LCD digital screen has broad application prospects in various fields, such as finance, medical treatment, multimedia production, architectural drawing, design and publishing.
There is a clear difference between drawing on a digital board and painting with paper and pencil. When drawing on real paper, the lines of the painting will be displayed directly on the paper along with the stroke of the pen. The pen and the paper are in the same plane and physically coincide. However, the physical dislocation produced by digital drawing board can not be eliminated by improving technical parameters, and the hand and eye can not be integrated, so it is impossible to provide the same experience as real paper and pen painting. In addition to spatial dislocation, there is also a problem of proportional dislocation in digital drawing boards. That is to say, the ratio of drawing area to display area can not be 1:1. Even if we choose the largest digital drawing board, its input area is much smaller than the display area of the current mainstream 22-inch or 24-inch display. Dimension differences lead to the drawing board can only be proportional mapping with the display. The direct consequence is that the moving speed of the pointer in the screen cannot be synchronized with the moving speed of the brush. When the brush moves about 1 cm, the pointer in the display may move 1.5 cm or more. These dislocation problems make many users who are used to drawing on paper unable to adapt for a while, and the painting LCD screen can solve these problems well. The following author talks about how to choose a suitable LCD painting screen according to the technical characteristics of this kind of products and some situations that may be encountered in practical use.
Virtual reality photography (VR photography), also known as panoramic photography, is a way of viewing wide-angle panoramic photographs, usually including 360-degree circular or spherical perspective.
VR photography is the art of taking or creating a complete scene as a single image, the effect of which is like the picture observed around a single central point and rotation. Usually it is a combination of many 360-degree rotational photographs or an omnidirectional camera. A complete virtual reality image can also be a completely computer-generated effect, or a combination of photography and computer-generated objects. VR photography is closely related to the history of simulating human-computer interaction in real or fictional environments. Users can interact and manipulate in the virtual world.
QuickTime VR (QTVR) is the original interactive panoramic format, and Apple's QuickTime software is its viewer software. The latest version of Microsoft Windows also provides built-in support through the.Pano file extension. [2] now has more and more players and plug-ins. Many of them are based on Flash, but some use Java, SilverLight, and programs customized using OpenGL and WebGL, as well as JavaScript. Most players can be found in the comparison entries of panoramic player.
VR photography can also be used to display objects in 360-degree perspective (360-degree photography, commonly known as 360-degree object VR, 360-degree product photography, 360-degree product image or 360-degree product perspective). They are obtained by rotating the object 360 degrees to take a series of images (the camera remains in a fixed position). [4] The output will be a series of individual images (usually in JPG format) that can then be used to form an interactive 360-degree view using HTML5, JavaScript, and/or Flash. The 360 degree object VR is often used in the field of electronic commerce.
1. the chassis should be placed as far as possible so as not to put it in a narrow space, affecting the air flow.
2. Airflow direction, try not to create convection, the more fans in the chassis, the better, but to have rules, generally a front of the chassis intake fan, after 1-2 exhaust fans.
3.CPU and heat sink should be properly added with silicone grease to enhance heat dissipation.
4. If the graphics card does not have a fan to add, if the graphics card display memory is not covered by the radiator, you can add the radiator yourself.
5. if there are two hard drives, try not to make the two hard drives too close.
6. do not add any overlay on the top of the display.
Unmanned aerial vehicles (UAVs), which appeared in the early and late 20th century, are characterized by small size, high mobility, low cost, easy operation, wide adaptability to combat environment, and no casualties. Especially since the 21st century, the function and application scope of UAV system is expanding constantly, and the development of UAV system is changing the mode of operation, which leads to a profound revolution in military affairs.
Therefore, UAV technology is a very important part of aviation technology. In the past, there were no separate UAV specialties and courses. Unmanned aerial vehicle (UAV) and conventional manned aerial vehicle (UAV) have many different contents and characteristics in technology. In order to meet the needs of the development of UAV in our country, UAV series courses are specially offered, among which “Introduction to UAV Design” is the leading and overall design course of UAV course.
The introduction of UAV design mainly trains students to understand the concept and characteristics of UAV, to preliminarily learn and master the theory, method and process of UAV overall design and structure design, to understand the relevant key technologies as UAV system, and to understand the UAV manufacturing, manufacturing methods and development process through some practical lessons.
This course enables students to have a comprehensive understanding of UAV design and lays a foundation for training technical and engineering personnel engaged in UAV.
The electronic ink screen has two advantages: power saving and eye protection.
The electronic ink screen can continuously display the picture without power supply. Only when the picture changes, it needs a small amount of power. For example, the Kindle can also display the screen when it is off, and the screen will refresh only when it is turned over. This characteristic will greatly reduce power consumption, and is also the reason for the continuation of e-books.
The traditional principle of LCD screen display is to use backlight to emit light, which needs to pass through the display screen all the time and shoot directly into the eyes. The electronic ink screen does not need backlight. It uses ambient light to hit the screen and refraction the eyes. This method simulates the characteristics of ink and paper. The stronger the ambient light, the clearer the display effect. Without flickering, it is not easy to feel tired during long hours of reading.
The features of electronic ink screen, such as power saving and eye protection, make it the first choice for e-book readers. Sony and Amazon have successively introduced readers equipped with electronic ink screen. Ten years have passed since the first Kindle was released, and the electronic ink screen has a history of 20 years. Since its birth, many people have high hopes for it. They believe that the electronic book will change the life of the paper book. But up to now, the electronic book has never become the mainstream of the market, and the electronic ink screen seems to have little obvious change. There seems to be no further improvement in technology.
2015年 电子书设计方案
电子书对阅读者来说是梦寐以求的产品，亚马逊为此开发了多款不同型号的电子书产品并获得非常大的成功，然而赛尚设计推出的电子书设计更让消费者眼前一亮，整体的设计突破了传统电子书一成不变的形状，新款的设计更让人有书本的感觉，完美的无边框墨水瓶让产品看上去更加美观大方，左边的手写笔更符合人们的看书习惯，写写画画非常方便。
The charging plug of mobile power charging treasure itself can charge mobile devices directly through AC power supply and has its own storage device, which is equivalent to a mixture of charger and standby battery. Compared with standby power supply, it can simplify a charging plug device, while compared with charger, it has its own storage device. It can provide backup power for digital products without direct power supply or outgoing.
The definition of mobile power charging treasure is the portable and portable power supply. It is a portable device that integrates power storage, boosting and charging management.
Mobile power charging treasure is also called "external battery", "backup battery", "digital charging companion". It also has a very personalized name: "mobile phone companion". The concept of "mobile power" has developed with the popularity and rapid growth of digital products. Its function is to provide charging function for mobile phones or digital products anytime and anywhere.
The real meaning of mobile power charging treasure is basically made of polymer lithium battery as storage unit. It is a lithium battery polymer storage device itself. It regulates the voltage by IC chip, charges or stores electricity by connecting the power cord, and then releases the stored energy. Charging treasure is relatively rare in the market. More of it is called charging treasure by backup batteries.
Overweight and underweight are unhealthy behaviors and are prone to many diseases. Overweight and obese people are susceptible to cardiovascular disease, diabetes and certain tumors. Those with normal weight should maintain their weight. Overweight and obese people suggest that they should control their weight to the normal range.
Whether weight is normal or not depends mainly on the balance between the amount of food eaten and the amount of exercise. Food provides energy and exercise consumes energy. If you eat too much and exercise too little, excess energy will be stored in the body in the form of fat, resulting in overweight or obesity; on the contrary, if you don't eat enough, it can cause low weight or weight loss.
Body mass index (BMI) = body weight (kg) / height (m) can be used to judge whether the body weight is normal or not. The normal body mass index (BMI) of adults ranged from 18.5 to 23.9 kg/m, the BMI ranged from 24 to 27.9 kg/m was overweight, and the BMI (> 28 kg/m) was obese.
Waist circumference is another common indicator of overweight and obesity. The warning line of normal waist circumference for adults is: males (> 85 cm) and females (> 80 cm); the overmarking line of adult waist circumference is: males (> 90 cm) and females (> 85 cm).
Solar energy refers to the energy that comes from the solar radiation and is utilized by a series of developing technologies, such as solar thermal collector, solar photovoltaic power generation, solar thermal power generation, and artificial photosynthesis.
Since the formation of the earth, living organisms have mainly survived by the heat and light provided by the sun. Since ancient times, humans have also known how to use sunlight to dry things and as a way of preserving food, such as salt making and salted fish. But with the reduction of fossil fuels, solar energy is intending to further develop.
Solar energy technology is divided into two types: active (active) and passive (passive). Active examples are solar photovoltaic and photothermal conversion, using electricity or mechanical equipment for solar energy collection, and these devices are operated by external energy, so they are called active. Passive examples include introducing sunlight into buildings for illumination, among which the use of building design, selection of materials used to achieve the purpose of utilizing solar energy, because the operation of which does not require external energy supply, so it is called passive.
Solar power generation is a new and renewable energy source. In general, solar energy is the source of many energy sources on earth, such as wind energy, chemical energy and potential energy of water. Fossil fuels can be called ancient solar energy. Solar energy resources are abundant and need not be transported, but the production of solar panels has serious environmental pollution, and will cause flight safety. Solar energy has created a new life form for human beings, which makes society and human beings enter an era of energy conservation and pollution reduction.
Wireless router is a router for users to surf the Internet and have wireless coverage function.
A wireless router can be seen as a transponder that forwards broadband network signals from the home wall to nearby wireless network devices (notebook computers, wifi-enabled mobile phones, tablets, and all WIFI-enabled devices) via an antenna.
The popular wireless routers in the market generally support four access modes: dedicated line xdsl/cable, dynamic xDSL and pptp. It also has other network management functions, such as DHCP service, NAT firewall, MAC address filtering, dynamic domain name and so on.
The popular wireless routers in the market generally support only 15-20 devices and use them online.
Generally, the signal range of wireless routers is 50 meters in radius, but now some of them have reached 300 meters in radius.
Wireless Router is like an extended product that combines simple wireless AP and broadband router. It not only has all functions of simple wireless AP, such as supporting DHCP client, VPN, firewall, WEP encryption, etc., but also includes network address translation (NAT) function, which can support LAN. The user's network connection is shared. It can realize Internet connection sharing in home wireless network, ADSL, Cable modem and wireless shared access of broadband in cell. Wireless routers can be directly connected to ADSL MODEM or CABLE MODEM connected to all Ethernet networks, or can be re-connected through local area networks such as switches/hubs and broadband routers when in use. Its built-in virtual dialing software can store username and password to dial on the Internet. It can provide automatic dialing function for ADSL and CM which dial into the Internet without manual dialing or using a computer as a server. In addition, wireless router generally has relatively perfect security protection function.
Laptop is a small, portable personal computer, usually weighing 1-3 kilograms. Its development trend is that the volume is smaller and smaller, the weight is lighter, but the function is stronger. Like Netbook, commonly known as netbook, the main difference from PC is that it is easy to carry. Compared with desktop computers, they are completely portable, and consume less power and generate less noise. However, they are usually slightly slower and less capable of processing graphics and sound than desktops. Besides, the price of notebook computers is also higher than that of desktops. But the price gap between them is narrowing - laptop prices are falling faster than desktops, and their actual sales exceeded desktops for the first time in May 2005.
Compared with desktop computers, notebook computers have similar structure (display, keyboard/mouse, CPU, memory and hard disk), but the advantages of notebook computers are still very obvious. Its main advantages are small size, light weight and easy to carry. Generally speaking, portability is the biggest advantage of notebook compared with desktop computer. The weight of general notebook computer is only about 2 kilograms. Whether it is working or traveling, it can be carried with you. It is very convenient.
Ultra-light and ultra-thin is the main development direction of notebook computers nowadays, but this has not affected the improvement of their performance and the enrichment of their functions. At the same time, its portability and backup power make mobile office possible. Because of these advantages, notebook computers are more and more praised by users, and the market capacity is expanding rapidly.
Global mini music mobile phone, mobile phone only 7.5CM above sea level, 3.4CM width, only 1/3 of the size of the general mobile phone, shorter than lighter, appearance is also "long pocket", "unique personality".
Although the mobile phone is small and full of internal organs, its basic functions are not inferior. MP3 music mobile phone, video playback, FM radio, file data encryption and other basic tools are available.
设计师刘怀在2009年为UMEOX设计超级迷你手机，采用前卫的糖果色为主色调，突出产品的鲜明质感，配合富有流动性线条的案件，使手机看上去非常的活泼明快，在手机界产生深远的影响。并在市场上获得惊人的销量。
Unmanned aerial vehicles (UAVs), which appeared in the early and late 20th century, are characterized by small size, high mobility, low cost, easy operation, wide adaptability to combat environment, and no casualties. Especially since the 21st century, the function and application scope of UAV system is expanding constantly, and the development of UAV system is changing the mode of operation, which leads to a profound revolution in military affairs.
Therefore, UAV technology is a very important part of aviation technology. In the past, there were no separate UAV specialties and courses. Unmanned aerial vehicle (UAV) and conventional manned aerial vehicle (UAV) have many different contents and characteristics in technology. In order to meet the needs of the development of UAV in our country, UAV series courses are specially offered, among which "Introduction to UAV Design" is the leading and overall design course of UAV course.
The introduction of UAV design mainly trains students to understand the concept and characteristics of UAV, to preliminarily learn and master the theory, method and process of UAV overall design and structure design, to understand the relevant key technologies as UAV system, and to understand the UAV manufacturing, manufacturing methods and development process through some practical lessons.
This course enables students to have a comprehensive understanding of UAV design and lays a foundation for training technical and engineering personnel engaged in UAV.
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