What time is better to go to the bath center
Publish: 2021-05-29 11:20:43
1. Hello
if there is no group purchase. Go in and tell them how many of you, wash your feet or massage. I'll take you to the small room. Then the technician will come in and ask you what kind of pedicure you want to do! If it's meituan, as soon as you go in, tell them you're a group buyer
just for personal point of view, don't spray if you don't like it, thank you.
if there is no group purchase. Go in and tell them how many of you, wash your feet or massage. I'll take you to the small room. Then the technician will come in and ask you what kind of pedicure you want to do! If it's meituan, as soon as you go in, tell them you're a group buyer
just for personal point of view, don't spray if you don't like it, thank you.
2. This is not necessarily. It depends on your hobbies. If you like something, you can go. If you don't like it, you can't go. In fact, it's nothing. The key is to grasp the degree. It's usually at night.
3. Big, regular, cleaning, or housewife
4. There's no standard, and the constitution doesn't mention it. Ask the boss. The laundry room is good
5. The bath center should set the time to start counting! It will arrive at one o'clock in three hours
6. The snack bars on the pedestrian street of Zhongshan Road usually do business for tourists at night, so they open late. Some of them open at 9:00 a.m. and some in the afternoon.
7. Large bath center is generally open 24 hours, and is unlimited, you can stay as long as you want.
8. Because entertainment places such as nightclubs are leisure places. Only when you finish what you should be busy in the daytime can you go to leisure and entertainment in the evening. Some of them are entertainers. Of course, the customers you invite are also busy with work in the daytime. Going to entertainment places can't avoid drinking and so on. When you are tired, you will go to the sauna to let yourself completely relax, steam and soak, and some need massage The reason why I can have a good sleep
is that I drank wine before going to the sauna. Driven by alcohol, I can't help but have a bad temper and fight, so I'm in a mess
these are the main reasons
is that I drank wine before going to the sauna. Driven by alcohol, I can't help but have a bad temper and fight, so I'm in a mess
these are the main reasons
9. We can choose an integrated kindergarten and carry out normal intervention training in the early stage. Through ecation and training to a certain extent, autistic children can integrate with ordinary children to carry out learning and activities, so as to provide conditions for special children to establish classroom routines, learn cultural knowledge and smoothly enter the campus, so as to improve their peer relationship and social communication ability, And then lay a good foundation for children to integrate into society.
10. 1、 PCB (printed circuit board)
PCB is the abbreviation of printed circuit board, Chinese name is printed circuit board, also known as printed circuit board, printed circuit board, is an important electronic component, is the support of electronic components, is the provider of electrical connection of electronic components. Because it is made by electronic printing, it is called "printed" circuit board
History of PCB
the inventor of printed circuit board was Austrian Paul Eisler, who adopted printed circuit board in a radio device in 1936. In 1943, Americans used this technology in military radios. In 1948, the United States officially approved the invention for commercial use. Since the mid-1950s, printed circuit board technology began to be widely used
before the appearance of printed circuit board, the interconnection between electronic components was realized by direct wire connection. Now, the circuit board only exists as an effective experimental tool; Printed circuit board has occupied an absolute dominant position in the electronic instry
PCB design
the design of printed circuit board is based on the circuit schematic diagram to realize the functions required by the circuit designer. The design of printed circuit board mainly refers to the layout design, which needs to consider the layout of external connections, the optimal layout of internal electronic components, the optimal layout of metal wires and through holes, electromagnetic protection, heat dissipation and other factors. Excellent layout design can save proction cost and achieve good circuit performance and heat dissipation performance. Simple layout design can be realized by hand, while complex layout design needs the help of computer aided design (CAD)
PCB classification
according to the number of circuit layers, it is divided into single panel, double-sided board and multilayer board. The common multi-layer board is generally 4-layer board or 6-layer board, and the complex multi-layer board can reach more than 10 layers
there are three main types of PCB:
1. Single sided boards are the most basic PCB, with parts concentrated on one side and wires concentrated on the other. Because wires only appear on one side, this kind of PCB is called single sided. Because there are many strict restrictions on the design circuit of a single panel (because there is only one side, the wiring can not cross, but must go around its own path), only the early circuits used this kind of board
2. Double sided boards have wiring on both sides of the circuit board. However, to use the wires on both sides, it is necessary to have proper circuit connection between the two sides. The bridge between these circuits is called via. A pilot hole is a small hole in a PCB filled with or coated with metal, which can be connected with wires on both sides. Because the area of the double-sided board is twice as large as that of the single panel, and because the wiring can be staggered with each other (can be wound to the other side), it is more suitable for more complex circuits than the single panel
3. In order to increase the area of wiring, multi-layer boards use more single or double-sided wiring boards. Printed circuit boards with one double-sided inner layer, two single-sided outer layer, two double-sided inner layer and two single-sided outer layer are alternately connected by positioning system and insulating bonding materials, and the conctive patterns are interconnected according to the design requirements. They are also called multilayer printed circuit boards. The number of layers of a board represents that there are several independent wiring layers. Generally, the number of layers is even and includes the outermost two layers. Most of the motherboards are 4 to 8-layer structure, but technically, the theory can achieve nearly 100 layers of PCB board. Most large supercomputers use multi-layer motherboard, but because this kind of computer can be replaced by many ordinary computer clusters, the multi-layer motherboard has been graally not used. Because each layer of PCB is closely combined, it is not easy to see the actual number, but if you carefully observe the motherboard, you can still see it
according to the software and hardware, it can be divided into ordinary circuit board and flexible circuit board
raw material of PCB: copper clad laminate is the base material of PCB. It is used to support various components, and can realize the electrical connection or insulation between them
a PCB is a printed circuit board (PCB), which is simply a thin board with integrated circuits and other electronic components
it appears in almost every electronic device
according to a recent report by time magazine, China and India are among the most polluted countries in the world. In order to protect the environment, the Chinese government has been strictly formulating and implementing the relevant pollution control regulations, which have affected the PCB instry. Many towns are no longer allowed to expand and build new PCB factories, such as Shenzhen. Dongguan has designated four cities and towns as proction bases for "polluting instries", and it is forbidden to build new factories outside the designated areas
if there are electronic parts in a certain equipment, they are all embedded in PCB of different sizes. In addition to fixing all kinds of small parts, the main function of PCB is to provide the electrical connection between the top parts
with the increasing complexity of electronic equipment, more and more parts are needed, and the circuits and parts on PCB are more and more intensive. Bare board (without parts on it) is also often called & quot; Printed wiring board (PWB) & quot;. The base plate of the board itself is made of insulating and inflexible materials. The small circuit material that can be seen on the surface is copper foil. Originally, the copper foil was covered on the whole board, but part of it was etched out ring the manufacturing process, and the remaining part became a network of small circuits. These circuits are called conctor patterns, or wiring, and are used to provide circuit connections for parts on a PCB
generally, the color of PCB is green or brown, which is the color of solder mask. It is an insulating protective layer, which can protect copper wire and prevent parts from being welded to the wrong place. A layer of silk screen is printed on the solder mask. Usually, words and symbols (mostly white) will be printed on it to mark the position of each part on the board
in order to fix the parts on the PCB, we weld their pins directly on the wiring. In the most basic PCB (single panel), the parts are concentrated on one side, and the wires are concentrated on the other side. In this way, we need to make holes in the board, so that the pins can pass through the board to the other side, so the pins of the parts are welded on the other side, The front and back sides of PCB are called component side and solder side respectively.
if there are some parts on the top of PCB that can be removed or installed back after manufacturing, socket will be used when installing the parts, The parts can be disassembled and assembled at will.
if we want to connect two PCBs, we usually use the edge connector commonly known as "gold finger". The gold finger contains many exposed copper pads, which are actually part of PCB wiring, In a computer, such as a display card, a sound card or other similar interface card, the gold finger is used to connect with the motherboard.
the printed circuit board connects the complicated copper wires between parts through careful planning, Etched on a board, providing the main support for the installation and interconnection of electronic components, is an indispensable basic part of all electronic procts
a printed circuit board is a flat plate made of non-conctive materials, on which pre drilled holes are usually designed to mount chips and other electronic components. The holes of the components help to connect the metal paths that are pre-defined on the board in an electronic way. After the pins of the electronic components pass through the PCB, they are adhered to the PCB with conctive metal electrodes to form a circuit
according to its application fields, PCB can be divided into single panel, double-sided board, multi-layer board with more than four layers and flexible board. Generally speaking, the more complex the function of electronic procts, the longer the loop distance, and the more the number of contact pins, the more layers required for PCB, such as high-level consumer electronics, information and communication procts, etc; Flexible boards are mainly used in procts that need to be bent, such as notebook computers, cameras, automotive instruments, etc.
Second, PCB instry chain
according to the classification of the instry chain, it can be divided into raw materials - CCL - PCB - electronic proct application, and its relationship is simply expressed as:
glass fiber cloth: glass fiber cloth is one of the raw materials of CCL, which is made of glass fiber yarn, About 40% (thick plate) and 25% (thin plate) of the cost of CCL. Glass fiber yarn is made of silica sand and other raw materials calcined into liquid state in the kiln, drawn into very fine glass fiber through a very small alloy nozzle, and then hundreds of glass fibers are twisted into glass fiber yarn. The construction investment of the kiln is huge, which generally requires hundreds of millions of funds. Once the ignition is started, it must be proced 24 hours a day, and the cost of entering and exiting is huge. Similar to weaving enterprises, fiberglass manufacturing can control the proction capacity and quality by controlling the rotation speed, and the specifications are relatively single and stable, and there has been little change in specifications since World War II. Unlike CCL, the price of fiberglass cloth is most affected by the relationship between supply and demand. In recent years, the price of fiberglass cloth fluctuates between us $0.50-1.00/meter. At present, Taiwan and Mainland China account for about 70% of the world's proction capacity
copper foil: copper foil accounts for the largest proportion of the cost of copper clad laminate, accounting for about 30% (thick plate) and 50% (thin plate) of the cost of copper clad laminate. Therefore, the price rise of copper foil is the main driving force for the price rise of copper clad laminate. The price of copper foil is closely reflected in the price change of copper, but its bargaining power is weak. Recently, with the rising price of copper, copper foil manufacturers are in a difficult situation, many enterprises are forced to close down or be merged. Even if copper clad laminate manufacturers accept the rising price of copper foil, all copper foil manufacturers are still in a state of general loss. Due to the price gap, another wave of price increase is likely to appear in the first quarter of 2006, which may lead to the rise of CCL price
copper clad laminate: copper clad laminate is a proct of pressing glass fiber cloth and copper foil together with epoxy resin as fusion agent. It is the direct raw material of PCB and is made into printed circuit board after etching, electroplating and laminating. The capital demand of CCL instry is not high, about 30-40 million yuan, and it can stop proction or change proction at any time. In the upstream and downstream instrial chain structure, CCL has the strongest bargaining power. It can not only have a strong voice in the procurement of raw materials such as glass fiber cloth and copper foil, but also transfer the pressure of rising costs to the downstream PCB manufacturers as long as the downstream demand is acceptable. In the third quarter of this year, the price of CCL began to rise by about 5-8%. The main driving force is the rising price of copper foil, and the downstream demand is strong, which can absorb the pressure of CCL manufacturers. South Asia, the world's second largest copper clad laminate manufacturer, also raised proct prices on December 15, showing a good demand pattern for PCB in at least the first quarter of 2006< At present, the output value of the global PCB instry accounts for more than one fourth of the total output value of the electronic components instry, which is the subdivision of the electronic components instry
PCB is the abbreviation of printed circuit board, Chinese name is printed circuit board, also known as printed circuit board, printed circuit board, is an important electronic component, is the support of electronic components, is the provider of electrical connection of electronic components. Because it is made by electronic printing, it is called "printed" circuit board
History of PCB
the inventor of printed circuit board was Austrian Paul Eisler, who adopted printed circuit board in a radio device in 1936. In 1943, Americans used this technology in military radios. In 1948, the United States officially approved the invention for commercial use. Since the mid-1950s, printed circuit board technology began to be widely used
before the appearance of printed circuit board, the interconnection between electronic components was realized by direct wire connection. Now, the circuit board only exists as an effective experimental tool; Printed circuit board has occupied an absolute dominant position in the electronic instry
PCB design
the design of printed circuit board is based on the circuit schematic diagram to realize the functions required by the circuit designer. The design of printed circuit board mainly refers to the layout design, which needs to consider the layout of external connections, the optimal layout of internal electronic components, the optimal layout of metal wires and through holes, electromagnetic protection, heat dissipation and other factors. Excellent layout design can save proction cost and achieve good circuit performance and heat dissipation performance. Simple layout design can be realized by hand, while complex layout design needs the help of computer aided design (CAD)
PCB classification
according to the number of circuit layers, it is divided into single panel, double-sided board and multilayer board. The common multi-layer board is generally 4-layer board or 6-layer board, and the complex multi-layer board can reach more than 10 layers
there are three main types of PCB:
1. Single sided boards are the most basic PCB, with parts concentrated on one side and wires concentrated on the other. Because wires only appear on one side, this kind of PCB is called single sided. Because there are many strict restrictions on the design circuit of a single panel (because there is only one side, the wiring can not cross, but must go around its own path), only the early circuits used this kind of board
2. Double sided boards have wiring on both sides of the circuit board. However, to use the wires on both sides, it is necessary to have proper circuit connection between the two sides. The bridge between these circuits is called via. A pilot hole is a small hole in a PCB filled with or coated with metal, which can be connected with wires on both sides. Because the area of the double-sided board is twice as large as that of the single panel, and because the wiring can be staggered with each other (can be wound to the other side), it is more suitable for more complex circuits than the single panel
3. In order to increase the area of wiring, multi-layer boards use more single or double-sided wiring boards. Printed circuit boards with one double-sided inner layer, two single-sided outer layer, two double-sided inner layer and two single-sided outer layer are alternately connected by positioning system and insulating bonding materials, and the conctive patterns are interconnected according to the design requirements. They are also called multilayer printed circuit boards. The number of layers of a board represents that there are several independent wiring layers. Generally, the number of layers is even and includes the outermost two layers. Most of the motherboards are 4 to 8-layer structure, but technically, the theory can achieve nearly 100 layers of PCB board. Most large supercomputers use multi-layer motherboard, but because this kind of computer can be replaced by many ordinary computer clusters, the multi-layer motherboard has been graally not used. Because each layer of PCB is closely combined, it is not easy to see the actual number, but if you carefully observe the motherboard, you can still see it
according to the software and hardware, it can be divided into ordinary circuit board and flexible circuit board
raw material of PCB: copper clad laminate is the base material of PCB. It is used to support various components, and can realize the electrical connection or insulation between them
a PCB is a printed circuit board (PCB), which is simply a thin board with integrated circuits and other electronic components
it appears in almost every electronic device
according to a recent report by time magazine, China and India are among the most polluted countries in the world. In order to protect the environment, the Chinese government has been strictly formulating and implementing the relevant pollution control regulations, which have affected the PCB instry. Many towns are no longer allowed to expand and build new PCB factories, such as Shenzhen. Dongguan has designated four cities and towns as proction bases for "polluting instries", and it is forbidden to build new factories outside the designated areas
if there are electronic parts in a certain equipment, they are all embedded in PCB of different sizes. In addition to fixing all kinds of small parts, the main function of PCB is to provide the electrical connection between the top parts
with the increasing complexity of electronic equipment, more and more parts are needed, and the circuits and parts on PCB are more and more intensive. Bare board (without parts on it) is also often called & quot; Printed wiring board (PWB) & quot;. The base plate of the board itself is made of insulating and inflexible materials. The small circuit material that can be seen on the surface is copper foil. Originally, the copper foil was covered on the whole board, but part of it was etched out ring the manufacturing process, and the remaining part became a network of small circuits. These circuits are called conctor patterns, or wiring, and are used to provide circuit connections for parts on a PCB
generally, the color of PCB is green or brown, which is the color of solder mask. It is an insulating protective layer, which can protect copper wire and prevent parts from being welded to the wrong place. A layer of silk screen is printed on the solder mask. Usually, words and symbols (mostly white) will be printed on it to mark the position of each part on the board
in order to fix the parts on the PCB, we weld their pins directly on the wiring. In the most basic PCB (single panel), the parts are concentrated on one side, and the wires are concentrated on the other side. In this way, we need to make holes in the board, so that the pins can pass through the board to the other side, so the pins of the parts are welded on the other side, The front and back sides of PCB are called component side and solder side respectively.
if there are some parts on the top of PCB that can be removed or installed back after manufacturing, socket will be used when installing the parts, The parts can be disassembled and assembled at will.
if we want to connect two PCBs, we usually use the edge connector commonly known as "gold finger". The gold finger contains many exposed copper pads, which are actually part of PCB wiring, In a computer, such as a display card, a sound card or other similar interface card, the gold finger is used to connect with the motherboard.
the printed circuit board connects the complicated copper wires between parts through careful planning, Etched on a board, providing the main support for the installation and interconnection of electronic components, is an indispensable basic part of all electronic procts
a printed circuit board is a flat plate made of non-conctive materials, on which pre drilled holes are usually designed to mount chips and other electronic components. The holes of the components help to connect the metal paths that are pre-defined on the board in an electronic way. After the pins of the electronic components pass through the PCB, they are adhered to the PCB with conctive metal electrodes to form a circuit
according to its application fields, PCB can be divided into single panel, double-sided board, multi-layer board with more than four layers and flexible board. Generally speaking, the more complex the function of electronic procts, the longer the loop distance, and the more the number of contact pins, the more layers required for PCB, such as high-level consumer electronics, information and communication procts, etc; Flexible boards are mainly used in procts that need to be bent, such as notebook computers, cameras, automotive instruments, etc.
Second, PCB instry chain
according to the classification of the instry chain, it can be divided into raw materials - CCL - PCB - electronic proct application, and its relationship is simply expressed as:
glass fiber cloth: glass fiber cloth is one of the raw materials of CCL, which is made of glass fiber yarn, About 40% (thick plate) and 25% (thin plate) of the cost of CCL. Glass fiber yarn is made of silica sand and other raw materials calcined into liquid state in the kiln, drawn into very fine glass fiber through a very small alloy nozzle, and then hundreds of glass fibers are twisted into glass fiber yarn. The construction investment of the kiln is huge, which generally requires hundreds of millions of funds. Once the ignition is started, it must be proced 24 hours a day, and the cost of entering and exiting is huge. Similar to weaving enterprises, fiberglass manufacturing can control the proction capacity and quality by controlling the rotation speed, and the specifications are relatively single and stable, and there has been little change in specifications since World War II. Unlike CCL, the price of fiberglass cloth is most affected by the relationship between supply and demand. In recent years, the price of fiberglass cloth fluctuates between us $0.50-1.00/meter. At present, Taiwan and Mainland China account for about 70% of the world's proction capacity
copper foil: copper foil accounts for the largest proportion of the cost of copper clad laminate, accounting for about 30% (thick plate) and 50% (thin plate) of the cost of copper clad laminate. Therefore, the price rise of copper foil is the main driving force for the price rise of copper clad laminate. The price of copper foil is closely reflected in the price change of copper, but its bargaining power is weak. Recently, with the rising price of copper, copper foil manufacturers are in a difficult situation, many enterprises are forced to close down or be merged. Even if copper clad laminate manufacturers accept the rising price of copper foil, all copper foil manufacturers are still in a state of general loss. Due to the price gap, another wave of price increase is likely to appear in the first quarter of 2006, which may lead to the rise of CCL price
copper clad laminate: copper clad laminate is a proct of pressing glass fiber cloth and copper foil together with epoxy resin as fusion agent. It is the direct raw material of PCB and is made into printed circuit board after etching, electroplating and laminating. The capital demand of CCL instry is not high, about 30-40 million yuan, and it can stop proction or change proction at any time. In the upstream and downstream instrial chain structure, CCL has the strongest bargaining power. It can not only have a strong voice in the procurement of raw materials such as glass fiber cloth and copper foil, but also transfer the pressure of rising costs to the downstream PCB manufacturers as long as the downstream demand is acceptable. In the third quarter of this year, the price of CCL began to rise by about 5-8%. The main driving force is the rising price of copper foil, and the downstream demand is strong, which can absorb the pressure of CCL manufacturers. South Asia, the world's second largest copper clad laminate manufacturer, also raised proct prices on December 15, showing a good demand pattern for PCB in at least the first quarter of 2006< At present, the output value of the global PCB instry accounts for more than one fourth of the total output value of the electronic components instry, which is the subdivision of the electronic components instry
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