Xinhua News Agency reporter learned from the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences on the 24th that the Shenzhou 7 outboard activity lighting developed by the institute will provide illumination for astronauts out of the cabin and space image shooting. This will be the world's first lighting system using LED (light-emitting diode) light source as a manned spacecraft, and is China's first lighting system for space capsules.
Shenzhou Seven lights will play a very important role in astronaut spacewalking. After Shenzhou 7 enters the orbit, it will circle the earth every 90 minutes. There will be a period of time in the ground shadow area. At that time, the cabin is very dark. The astronauts must have light source lighting when they go out of the cabin, and the camera system needs lighting.
Researcher Zhang Tao, the person in charge of the development of Shenqi lighting, told reporters that Shenzhou seven lamps use the most advanced LED technology. China is also the first country in the world to adopt LED technology as a space capsule for outdoor cabin lighting. Before that, foreign countries generally used metal lamps for space capsule exterior lighting.
An LED, a light-emitting diode, is a solid-state semiconductor device that converts electricity directly into light. LED technology is characterized by high luminous efficiency, high reliability, good seismic performance, and theoretically up to 100,000 hours of service life. The color and structure of light can be flexibly adjusted.
Its principle is the same as that of the Water Cube of the Beijing Olympic Swimming Pool. However, because the lighting is used in the special environment of space, it is necessary to carry out all aspects of technical research. Zhang Tao said.
The difficulty of conquering the seven lights is mainly: First, the outer space environment is very complicated, the temperature of the ground shadow area may be minus six or seventy degrees, the temperature of the sunshine area is very high, and there are many radiations and static electricity in various spaces. Withstand these harsh environments. Previously, LED lighting developed by the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences was used for in-cabin lighting of some satellites, but the environment from cabin to cabin is very different.
Secondly, there is no air in outer space, and the illumination source cannot be dissipated by air convection as it is on the earth. It is necessary to fully utilize the heat dissipation technology of metal conduction and heat radiation.
Third, the aerospace lighting system needs to achieve high efficiency and low power consumption. At present, the luminous efficiency of LEDs has been able to achieve more than 100 lumens per watt in the laboratory. At the same time, the power consumption of the Shenqi lighting system is very small, only 27 watts, saving valuable energy for other working parts of Shenzhou.
Researchers have undertaken the Shenqi Lighting System project since 2003, and delivered the sample in May 2007. After years of research, the above problems were solved. For example, the surface of the Shenzhou seven illuminator is selected from an inorganic coating, which can reflect sunlight in the sunshine area and radiate its own heat in the ground shadow area.
Zhang Tao told reporters that the Shenzhou illuminator looks like a square box as a whole, and the illuminating surface is a polyhedron with a certain curvature. The function is to concentrate the light to the place where it is intended to be illuminated. The illumination angle of view is 160 degrees left and right and 90 degrees above and below. The Shenzhou seven lights contain 24 illumination sources with a total power consumption of 27 watts.
Such a high-tech lighting system, which is small in scale, is a small box about 20 cm wide, about 10 cm high and about 6 cm thick, weighing about 1.8 kg. Do not misunderstand it. The total load of aerospace equipment has strict requirements. The requirements for system accessories are minimum power consumption, minimum volume, and lightest quality. The smaller the size, the higher the technical content. Zhang Tao said.
God Seven Flying Sky LED Outlet Lights Light up the First Step in Space
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Weak cables refer to cables used for security communications, electrical equipment, and related weak current transmission applications.
Wire and cable refers to materials used for power, communications, and related transmission purposes. "Wire" and "cable" do not have strict boundaries. Usually, the product with a small number of cores, a small product diameter, and a simple structure is called a wire. A wire without insulation is called a bare wire. Others are called cables. A conductor with a larger cross-sectional area (greater than 6 mm2) is called a large wire. Small (less than or equal to 6 mm2) is called a small wire, and an insulated wire is also called a cloth wire.
Wire and cable include bare wires, electromagnetic wires and insulated wires for electrical appliances, power cables, communication cables and optical cables.
1, the content included in the product name
(1) Product application or size class name
(2) product structure materials or types;
(3) Important or additional features of the product
Basically named in the above order, sometimes to highlight important or additional features, features are written before or before the corresponding structure description.
2, the order of the structure description
The product structure is described in terms of the principle from the inside to the outside: Conductor-->insulation-->inner sheath-->outer sheath.
3, simplified
Some structures describe writing or abbreviations without causing confusion.
Composition
From the inside to outside by the inner conductor, insulation, outer conductor and sheath;
Inner conductor: Since the attenuation is mainly caused by the resistance of the inner conductor, the inner conductor has a great influence on the signal transmission
Insulation: Impact attenuation, resistance, return loss and other properties
Outer conductor: loop conductor, shielding effect
Video signal transmission generally adopts direct modulation technology and takes the form of baseband frequency (about 8MHz bandwidth). The most common transmission medium is Coaxial Cable; coaxial cable is specially designed to transmit video signals, and its frequency loss, image distortion, The amplitude of image attenuation is relatively small, which can well complete the task of transmitting video signals.
Commonly used special SYV75 ohm series coaxial cable; commonly used model is SYV75-5 (its non-relay transmission distance for the video signal is generally 300-500m); when the distance is long, SYV75-7, SYV75-9 must be used Axle cable (In actual engineering, the relayless transmission distance of the thick cable can reach 1km or more)
The communication cable is generally used in an imaging device equipped with an electric pan/tilt head and an electric lens, and a remote control decoder must be installed in the field when in use; a communication transmission cable between the on-site decoder and the video matrix switching host of the control center is generally adopted. 2-core shielded communication cable (RVVP) or category 3 twisted pair UTP, with a cross-sectional area per core of 0.3mm² ~0.5mm²; the basic principle for selecting a communication cable is that the longer the distance, the larger the wire diameter; RS-485 communication regulations The basic communication distance is 1200m, but in the actual project, the RVV2-1.5 sheath line can be used to extend the communication length to over 2000m.
The control cable usually refers to the multi-core cable used to control the PTZ and the electric variable lens; one end of the control cable is connected to the PTZ of the controller or the decoder, and the electric lens controls the terminal, and the other end is directly connected to the PTZ. On the corresponding terminals of the electric lens, the control cable provides DC or AC voltage, and the distance is generally short (sometimes less than 1m). There is basically no interference problem, so no Shielded Cable is required.
Commonly used control cables mostly use 6-core or 10-core cables, such as RVV6-0.2, RVV10-0.12; 6-core cables are connected to the top, bottom, left, right, automatic, and public 6 terminals of PTZ respectively, 10 cores In addition to the six terminals of the pan-tilt head, the cable includes four zooming, focusing, aperture, and common terminals of the electric lens; in the monitoring system, the control cable from the decoder to the pan/tilt head and the lens is short due to the short distance. Generally do not make special requirements; and from the central control room controller to the pan and tilt and electric lens distance is as small as tens of meters, as many as several hundred meters, the control cable needs to have certain requirements, that is, the diameter of the wire should be thick, such as selection RVV10-0.5, RVV10-0.75
Audio Monitoring Cable generally uses 4-core shielded communication cable (RVVP) or Category 3 twisted pair UTP, with a cross-sectional area of 0.5 mm² per core;
The audio signal of the monitor head in the monitoring system is transmitted to the central control room and is a point-to-point wiring method. It is transmitted with high voltage and low current, so an unshielded 2-core cable can be used, such as RVV2-0.5.
RVV2*0.3 (signal line) and RVV4*0.3 (2-core + 2-core power) cables are generally used between the front-end detector and the alarm controller; the two controllers are generally used between the alarm controller and the terminal security center. Signal line
Whether the signal line is shielded or twisted or it is a common sheathed cable, it needs to be determined according to the requirements of various brands of products; the rough specification of the signal line diameter is determined according to the distance and quality of the alarm controller and the center; alarm control The power supply of the device generally uses local power instead of centralized power supply in the control room. The line is short, generally adopting RVV 2×0.5" or above specifications; the perimeter alarm and other public area alarm devices generally use centralized power supply mode, and the line is longer. RVV2*1.0" or above specifications are generally used
Cables used in building intercom systems are mostly cables such as RVV, RVVP, SYV, etc.
Has: transmission of voice, data, video images, while cable requirements also reflected in the quality of voice transmission, data transmission rate, video image transmission quality and speed, etc.
Cables that transmit voice signals and alarm signals mainly use RVV4-8*1.0
Video transmission is based on SYV75-5 cable
Some systems must use RVVP cables in the system when they are afraid of external interference or cannot be grounded.
Direct Push-to-Talk Visual Intercom System Line Standard:
Video terminals, two-way audio and remote control unlocking terminals of all indoor units are connected to the door machine in a bus way, but each call line is directly connected to the door machine alone.
--Video coaxial cable SYV75-5, SYV75-3
- Use a 4-core non-shielded or shielded sheath cable (AVVR4, RVV4, or RVVP4, etc.) for the microphone/speaker/unlock cord
- A 2-core jacket wire (AVVR2, RVV2, etc.) for the power cord
-- 2-wire shielded cable for call lines (RVVP2)
Digital coded push-button video intercom system:
- The main line includes video coaxial cable (SYV75-5, SYV75-3, etc.)
- Power cord (AVVR2, RVV2, etc.)
-- Audio/data control lines (RVVP4, etc.)
- Household Signal Line (RVVP6, etc.)
Low Current Cables,Charter Cable,Spectrum Cable,Coaxial Cable
Jiangsu QiSheng Cable Co., Ltd. , http://www.shuaihe-cable.com