Warning: mysql_query() [function.mysql-query]: Unable to save result set in D:\wwwroot\20911.net\includes\db.inc.php on line 67
Database error: Invalid SQL: select count(id) from pwn_comment where pid='3723' and iffb='1'
MySQL Error: 1194 (Table 'pwn_comment' is marked as crashed and should be repaired)
#0 dbbase_sql->halt(Invalid SQL: select count(id) from pwn_comment where pid='3723' and iffb='1') called at [D:\wwwroot\20911.net\includes\db.inc.php:73] #1 dbbase_sql->query(select count(id) from {P}_comment where pid='3723' and iffb='1') called at [D:\wwwroot\20911.net\comment\module\CommentContent.php:65] #2 CommentContent() called at [D:\wwwroot\20911.net\includes\common.inc.php:518] #3 printpage() called at [D:\wwwroot\20911.net\comment\html\index.php:13]
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in D:\wwwroot\20911.net\includes\db.inc.php on line 80

Warning: mysql_query() [function.mysql-query]: Unable to save result set in D:\wwwroot\20911.net\includes\db.inc.php on line 67
Database error: Invalid SQL: select * from pwn_comment where pid='3723' and iffb='1' order by id limit 0,10
MySQL Error: 1194 (Table 'pwn_comment' is marked as crashed and should be repaired)
#0 dbbase_sql->halt(Invalid SQL: select * from pwn_comment where pid='3723' and iffb='1' order by id limit 0,10) called at [D:\wwwroot\20911.net\includes\db.inc.php:73] #1 dbbase_sql->query(select * from {P}_comment where pid='3723' and iffb='1' order by id limit 0,10) called at [D:\wwwroot\20911.net\comment\module\CommentContent.php:167] #2 CommentContent() called at [D:\wwwroot\20911.net\includes\common.inc.php:518] #3 printpage() called at [D:\wwwroot\20911.net\comment\html\index.php:13]
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in D:\wwwroot\20911.net\includes\db.inc.php on line 80
 客户点评-Infrared (IR) Gentle Is Electromagnetic Radiation With A Wavelength Longer Than That Of Seen Gentle, But Shorter Than That Of Microwaves. The Identify Consists Of The Latin Word Infra (meaning Below) 世界杯2022几月份开始_2022世界杯赛程-世界杯资讯
 
 
点评详情
发布于:2021-8-26 20:15:41  访问:151 次 回复: 篇
版主管理 | 推荐 | 删除 | 删除并扣分
Infrared (IR) Gentle Is Electromagnetic Radiation With A Wavelength Longer Than That Of Seen Gentle, But Shorter Than That Of Microwaves. The Identify Consists Of The Latin Word Infra (meaning Below)
Infrared (IR) gentle is electromagnetic radiation with a wavelength longer than that of seen gentle, but shorter than that of microwaves. The identify consists of the Latin word infra (meaning below) and pink, which is the color of the longest wavelength seen light. The wavelength of infrared radiation varies from about 750 nanometres (the close to infrared) to 1 millimetre (the far infrared). Frequencies range from about 300 GHz to 400 THz. Infrared transmission systems are extensively used for short-range communications. A common software for infrared is in distant control systems for televisons, VCRs, DVD players and set-high bins of assorted descriptions. Infrared transmitters are often comparatively directional, cheap, lightweight, dependable and straightforward to manufacture. The primary drawback is that infrared gentle will not pass via stable objects. On the plus aspect, an infrared system in a single room of a building will not interfere with related systems in close by rooms, and the potential of eavesdropping is way decrease than with radio-based systems. Infrared communication is subsequently a practical alternative for indoor wireless LANs. The Infrared Information Association (IrDA), an business-sponsored organisation set up in 1993 to develop standards for infrared communication hardware and software, defines the bodily interface specifications and communications protocol standards for short-range data communications in applications resembling personal space networks (PANs). IrDA interfaces have been extensively used for communication between units corresponding to palmtop and laptop computer computer systems, cell phones, and http://idea.informer.com/users/fatherwhite0/?what=personal private knowledge assistants (PDAs). In recent years, Bluetooth has been supplied as a substitute interface in such units, but because the early 2000s has largely replaced IrDa as the wireless interface in new products, since the price of this technology has fallen quickly, and in contrast to IrDa it doesn`t require direct line of sight and may assist hardware comparable to wireless mice and keyboards. IrDa is still used in environments where interference makes radio-based wireless applied sciences unusable, and has the additional advantage that its bandwidth just isn`t topic to authorities regulation. IrDa transceivers talk utilizing pulses of infrared mild transmitted in a directionally centered cone that extends to an angle of 15o either side of the transmission`s centreline. Though the usual requires a minimal vary of 1 metre for a normal energy output, commercially out there merchandise have ranges various from less than a metre as much as several metres. Communication is half-duplex, for the reason that receiver of the infrared gadget is successfully \"blinded\" by the sunshine of its personal transmission. Knowledge charges fluctuate from 9.6 kbps as much as sixteen Mbps (9.6 kbps is the lowest common denominator for all units, and as such is used for negotiation between communicationg devices). An Ultra Quick Infrared (UFIR) protocol is at present being developed that may help information charges of as much as 100 Mbps. IrDa units are broadly described as both primary or secondary units. The primary machine initiates communication, sends commands, and handles data-circulation control (handshaking). Secondary gadgets simply respond to requests from main gadgets. Infrared laser techniques will also be used for long-range communication (as much as about 2.Four kilometres), with a maximum projected information charge of sixteen Mbps. Such programs are stricly level-to-point (line-of-sight) systems, and are delicate to fog and different atmospheric circumstances. Typical purposes include building-to-constructing transmission links for metropolitan or campus-space networks, and transmitting and receiving devices are sometimes located on rooftops to provide unobstructed line-of-sight hyperlinks. Diffuse (or non-line-of-sight) methods may be used for wireless LAN connectivity, through which the link between transmitter and receiver is maintained by \"bouncing\" the transmitted alerts off reflecting surfaces similar to walls and ceilings. The transmitter employs a large-angle transmit beam, and the receiver has a wide-angle detector. The specs for infrared wireless LANs are covered in the IEEE 802.Eleven normal. An infrared transmitting gadget, both a light-emitting diode (LED) or a laser diode, converts an electrical signal to an optical signal. LEDs have a naturally vast transmission path and are appropriate for short-vary purposes. They are additionally much safer than laser diodes for indoor use. Laser diodes have narrow transmit beams and a relatively narrow spectral width, making them extra suitable for level-to-level long-range purposes. Most programs use intensity modulation with direct detection (IM/DD) to achieve optical modulation and demodulation. The transmitted sign`s intensity or power is proportional to the modulating signal, and a photodetector at the receiver produces an output current proportional to the received optical signal intensity. In most working environments, the detector can also be illuminated by different sources of mild power, embody ambient mild sources equivalent to sunlight or artificial light sources. These light sources signify a big noise component at the receiver. The availability of effective, low-price LEDs and photodiodes operating in the 800-1000 nanometre range has led to the requirement for transmitters to have a peak-energy wavelength of between 850 and 950 nanometres.
共篇回复 每页10篇 页次:1/1
共篇回复 每页10篇 页次:1/1
我要回复
回复内容
验 证 码
看不清?更换一张
匿名发表 
当前位置
脚注信息
版权所有 Copyright(C)2009-2022 世界杯2022几月份开始_2022世界杯赛程-世界杯资讯