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1、<p><b> AT89S52</b></p><p> The AT89S52 is a low-power, high-performance CMOS 8-bit microcomputer with 8K bytes of Flash programmable and erasable read only memory (PEROM). The device is m
2、anufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80S51 and 80S52 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed
3、 in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monoli</p><p> The AT89S52 provides the following standard features: 8K bytes of Flash, 256
4、bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full-duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static
5、 logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system </p><p
6、> VCC: Supply voltage.</p><p> GND: Ground.</p><p> Port 0: Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are writte
7、n to port 0 pins, the pins can be used as high-impedance inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses to external pro-gram and data memory. In this mode, P0 has i
8、nternal pullups. Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External p</p><p> Port 1: Port 1 is an 8-bit bi-directional I/O port wi
9、th internal pullups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 1 pins that are
10、externally being pulled low will source current (IIL) because of the internal pullups. In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger
11、 input </p><p> Port 2: Port 2 is an 8-bit bi-directional I/O port with internal pullups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high
12、by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups. Port 2 emits the high-order address byte during fe
13、tches from external program memory and during accesses to external data memory that use 16</p><p> Port 3: Port 3 is an 8-bit bi-directional I/O port with internal pullups. The Port 3 output buffers can sin
14、k/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL)
15、because of the pullups. Port 3 also serves the functions of various special features of the AT89C51, as shown in the following table. Port 3 also receives some control signa</p><p> RST: Reset input. A high
16、 on this pin for two machine cycles while the oscillator is running resets the device.</p><p> ALE/: Address Latch Enable is an output pulse for latching the</p><p> low byte of the address du
17、ring accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for exter
18、nal timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set,
19、ALE is active only during a MOVX o</p><p> :Program Store Enable is the read strobe to external pro-gram memory. When the AT89S52 is executing code from external pro-gram memory, is activated twice each ma
20、chine cycle, except that two activations are skipped during each access to external data memory.</p><p> /VPP:External Access Enable. must be strapped to GND in order to enable the device to fetch code fro
21、m external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, will be internally latched on reset.</p><p> should be strapped to Vcc for internal progr
22、am executions. This pin also receives the 12-volt programming enable voltage (Vpp) during Flash programming when 12-volt programming is selected.</p><p> XTAL1:Input to the inverting oscillator amplifier an
23、d input to the internal clock operating circuit.</p><p> XTAL2:Output from the inverting oscillator amplifier.</p><p> Special Function Registers:A map of the on-chip memory area called the Sp
24、ecial Function Register (SFR) space is shown in Table 1.Note that not all of the addresses are occupied, and unoccupied addresses may not be implemented on the chip. Read accesses to these addresses will in general retur
25、n random data, and write accesses will have an indeterminate effect. User software should not write 1s to these unlisted locations, since they may be used in future products to invoke new features. In that c</p>&
26、lt;p> Data Memory:The AT89S52 implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a parallel address space to the Special Function Registers. That means the upper 128 bytes have the same addresses as the
27、SFR space but are physically separate from SFR space. When an instruction accesses an internal location above address 7FH, the address mode used in the instruction specifies whether the CPU accesses the upper 128 bytes o
28、f RAM or the SFR space. Instructions that use direct addressing access</p><p> MOV 0A0H, #data</p><p> Instructions that use indirect addressing access the upper128 bytes of RAM. For example,
29、the following indirect addressing instruction, where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H).</p><p> MOV @R0, #data</p><p> Note that
30、stack operations are examples of indirect addressing, so the upper 128 bytes of data RAM are available as stack space.</p><p> Infrared </p><p> Infrared (IR) light i
31、s electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible re
32、d light at 0.74 microm-etres (µm), and extending conventionally to 300 µm. These wavelengths correspond to a frequency r
33、ange of approximately 1 to 400 THz, and include most of the thermal radiation emitted by objects near room temperature.
34、Microscopically, IR light is typically emitted or absorbed by molecules when they change their rotational-vibratio</p><p> Infrared
35、;light is used in industrial, scientific, and medical applications. Night-vision devices using infrared illumination allow people or an
36、imals to be observed without the observer being detected. In astronomy, imaging at infrared wavelengths allows observation of obje
37、cts obscured by interstellar dust. Infrared imaging cameras are used to detect heat loss in insulated systems, observe changing
38、60;blood flow in the skin, and overheating of electrical apparatus. Much of the energy from the Sun ar</p><p> The balanc
39、e between absorbed and emitted infrared radiation has a critical effect on the Earth's climate. Objects generally emit infrare
40、d radiation across a spectrum of wavelengths, but sometimes only a limited region of the spectrum is of interest because
41、;sensors usually collect radiation only within a specific bandwidth. Therefore, the infrared band is often subdivided into smaller
42、;sections. Much of the energy from the Sun arrives on Earth in the form of infrared radiation. Sunlight at zenith </p>
43、<p> The balance between absorbed and emitted infrared radiation has a critical effect on the Earth's climate. Objects gener
44、ally emit infrared radiation across a spectrum of wavelengths, but sometimes only a limited region of the spectrum is of
45、;interest because sensors usually collect radiation only within a specific bandwidth. Therefore, the infrared band is often subdivided&
46、#160;into smaller sections. </p><p> Heat/Heating </p><p> Infrared radiation is popularly known as "heat radiation", but
47、light and electromagnetic waves of any frequency will heat surfaces that absorb them.</p><p> Infrared light from the Sun only
48、 accounts for 49% of the heating of the Earth, with the rest being caused by visible light that is absorbed then
49、60;re-radiated at longer wave lengths. Visible light or ultraviolet-emitting lasers can char paper and incandescently hot objects emit visib
50、le radiation. Objects at room temperature will emit radiation mostly concentrated in the 8 to 25 µm band, but this
51、is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hott</p><p> Heat is
52、160;energy in transient form that flows due to temperature difference. Unlike heat transmitted by thermal conduction or thermal co
53、nvection, radiation can propagate through a vacuum. </p><p> The concept of emissivity is important in understanding the infra
54、red emissions of objects. This is a property of a surface which describes how its thermal emissions deviate from the ide
55、al of a black body. To further explain, two objects at the same physical temperature will not "appear" the same
56、0;temperature in an infrared image if they have differing emissivities.</p><p> Thermography</p><p> Infrared radiation can be
57、used to remotely determine the temperature of objects (if the emissivity is known). This is termed thermography, or in the
58、60;case of very hot objects in the NIR or visible it is termed pyrometry. Thermography (thermal imaging) is mainly used
59、in military and industrial applications but the technology is reaching the public market in the form of infrared cameras on
60、160;cars due to the massively reduced production costs. Thermographic. cameras detect radiation in the infrared ra</p><p> Climatology&l
61、t;/p><p> In the field of climatology, atmospheric infrared radiation is monitored to detect trends in the energy exchange b
62、etween the earth and the atmosphere. These trends provide information on long term changes in the Earth's climate. It is&
63、#160;one of the primary parameters studied in research into global warming together with solar radiation.</p><p> A pyrgeometer
64、0;is utilized in this field of research to perform continuous outdoor measurements. This is a broadband infrared radiometer with
65、160;sensitivity for infrared radiation between approximately 4.5 µm and 50 µm. Night vision </p><p> Infrared is used
66、0;in night vision equipment when there is insufficient visible light to see. Night vision devices operate through a process i
67、nvolving the conversion of ambient light photons into electrons which are then amplified by a chemical and electrical process
68、;and then converted back into visible light.</p><p> Infrared light sources can be used to augment the available ambient
69、light for conversion by night vision devices, increasing in-the-dark visibility without actually using a visible light source. The
70、;use of infrared light and night vision devices should not be confused with thermal imaging which creates images based on dif
71、ferences in surface temperature by detecting infrared radiation (heat) that emanates from objects and their surrounding environment. Astrono
72、my </p><p> Astronomers observe objects in the infrared portion of the electromagnetic spectrum using optical components, including
73、 mirrors, lenses and solid state digital detectors. For this reason it is classified as part of optical astronomy. To fo
74、rm an image, the components of an infrared telescope need to be carefully shielded from heat sources, and the detectors
75、are chilled using liquid helium. </p><p> The sensitivity of Earth-based infrared telescopes is significantly limited by water
76、;vapor in the atmosphere, which absorbs a portion of the infrared radiation arriving from space outside of selected atmospheric
77、60;windows. This limitation can be partially alleviated by placing the telescope observatory at a high altitude, or by carrying
78、60;the telescope aloft with a balloon or an aircraft. Space telescopes do not suffer from this handicap, and so outer sp
79、ace is considered the ideal location for infra</p><p> Infrared light is also useful for observing the cores of active
80、60;galaxies which are often cloaked in gas and dust. Distant galaxies with a high redshift will have the peak portion of
81、 their spectrum shifted toward longer wavelengths, so they are more readily observed in the infrared. The discovery of infrar
82、ed radiation is ascribed to William Herschel, the astronomer, in the early 19th century. Herschel published his results in 18
83、00 before the Royal Society of London. Herschel used a prism to refra</p><p> The discovery of infrared radiation is
84、;ascribed to William Herschel, the astronomer, in the early 19th century. Herschel published his results in 1800 before the R
85、oyal Society of London. Herschel used a prism to refract light from the sun and detected the infrared, beyond the red
86、60;part of the spectrum, through an increase in the temperature recorded on a thermometer. He was surprised at the result
87、0;and called them "Calorific Rays". The term 'Infrared' did not appear until late in the 19th century.</p><p>
88、;<b> AT89S52</b></p><p> AT89S52是美國(guó)ATMEL公司生產(chǎn)的低電壓,高性能CMOS 8位單片機(jī),片內(nèi)含8k bytes的可反復(fù)擦寫的只讀程序存儲(chǔ)器(PEROM)和256 bytes的隨機(jī)存取數(shù)據(jù)存儲(chǔ)器(RAM)器件采用ATMEL公司的高密度、非易失性存儲(chǔ)技術(shù)生產(chǎn),與標(biāo)準(zhǔn)MCS-51指令系統(tǒng)及8052產(chǎn)品引腳兼容,片內(nèi)置通用8位中央處理器(CPU)和Fla
89、sh存儲(chǔ)單元,功能強(qiáng)大AT89S52單片機(jī)適合于許多較為復(fù)雜控制應(yīng)用場(chǎng)合。</p><p><b> 主要性能參數(shù)有 </b></p><p> ·與MCS-51產(chǎn)品指令和引腳完全兼容 </p><p> ·8k字節(jié)可重擦寫Flash閃速存儲(chǔ)器 </p><p> ·1000次擦寫周
90、期 </p><p> ·全靜態(tài)操作:0Hz-24MHz </p><p> ·三級(jí)加密程序存儲(chǔ)器 </p><p> ·256×8字節(jié)內(nèi)部RAM </p><p> ·32個(gè)可編程I/O口線 </p><p> ·3個(gè)16位定時(shí)/計(jì)數(shù)器 </
91、p><p><b> ·8個(gè)中斷源 </b></p><p> ·可編程串行UART通道 </p><p> ·低功耗空閑和掉電模式</p><p> 功能特性概述: AT89S52提供以下標(biāo)準(zhǔn)功能:8k字節(jié)Flash閃速存儲(chǔ)器,256字節(jié)內(nèi)部RAM,32個(gè)I/O口線,3個(gè)16位定時(shí)/計(jì)
92、數(shù)器,一個(gè)6向量?jī)杉?jí)中斷結(jié)構(gòu),一個(gè)全雙工串行通信口,片內(nèi)振蕩器及時(shí)鐘電路。同時(shí),AT89S52可降至0Hz的靜態(tài)邏輯操作,并支持兩種軟件可選的節(jié)電工作模式??臻e方式停止CPU的工作,但允許RAM,定時(shí)/計(jì)數(shù)器,串行通信口及中斷系統(tǒng)繼續(xù)工作。掉電方式保存RAM中的內(nèi)容,但振蕩器停止工作并禁止其它所有部件工作直到下一個(gè)硬件復(fù)位。</p><p> ·P0口:P0口是一組8位漏極開路型雙向I/O口,也即地址
93、/數(shù)據(jù)總線復(fù)用口。作為輸出口用時(shí),每位能吸收電流的方式驅(qū)動(dòng)8個(gè)TTL邏輯門電路,對(duì)端口P0寫“l(fā)”時(shí),可作為高阻抗輸入端用。 </p><p> 在訪問(wèn)外部數(shù)據(jù)存儲(chǔ)器或程序存儲(chǔ)器時(shí),這組口線分時(shí)轉(zhuǎn)換地址(低8位)和數(shù)據(jù)總線復(fù)用,在訪問(wèn)期間激活內(nèi)部上拉電阻。 在Flash編程時(shí),P0口接收指令字節(jié)。而在程序校驗(yàn)時(shí),輸出指令字節(jié),校驗(yàn)時(shí),要求外接上拉電阻。</p><p> ·P
94、1口:P1是一個(gè)帶內(nèi)部上拉電阻的8位雙向I/O口,P1的輸出緩沖級(jí)可驅(qū)動(dòng)(吸收或輸出電流)4個(gè)TTL邏輯門電路。對(duì)端口寫“l(fā)”,通過(guò)內(nèi)部的上拉電阻把端口拉到高電平,此時(shí)可作輸入口。作輸入口使用時(shí),因?yàn)閮?nèi)部存在上拉電阻,某個(gè)引腳被外部信號(hào)拉低時(shí)會(huì)輸出一個(gè)電流()。 與AT89C5l不同之處是,P1.0和P1.1還可分別作為定時(shí)/計(jì)數(shù)器2的外部計(jì)數(shù)輸入(P1.0/T2)和輸入(P1.1/T2EX)。Flash編程和程序校驗(yàn)期間,Pl接收低8
95、位地址。</p><p> ·P2口:P2是一個(gè)帶有內(nèi)部上拉電阻的8位雙向I/O口,P2的輸出緩沖級(jí)可驅(qū)動(dòng)(吸收或輸出電流)4個(gè)TTL邏輯門電路。對(duì)端口P2寫“l(fā)”,通過(guò)內(nèi)部的上拉電阻把端口拉到高電平,此時(shí)可作輸入口,作輸入口使用時(shí),因?yàn)閮?nèi)部存在上拉電阻,某個(gè)引腳被外部信號(hào)拉低時(shí)會(huì)輸出一個(gè)電流()。 </p><p> 在訪問(wèn)外部程序存儲(chǔ)器或16位地址的外部數(shù)據(jù)存儲(chǔ)器(例如執(zhí)
96、行MOVX@DPTR指令)時(shí),P2口送出高8位地址數(shù)據(jù)。在訪問(wèn)8位地址的外部數(shù)據(jù)存儲(chǔ)器(如執(zhí)行MOVX@RI指令)時(shí),P2口輸出P2鎖存器的內(nèi)容。 Flash編程或校驗(yàn)時(shí),P2亦接收高位地址和一些控制信號(hào)。</p><p> ·P3口:P3口是一組帶有內(nèi)部上拉電阻的8位雙向I/O口。P3口輸出緩沖級(jí)可驅(qū)動(dòng)(吸收或輸出電流)4個(gè)TTL邏輯門電路。對(duì)P3口寫入“l(fā)”時(shí),它們被內(nèi)部上拉電阻拉高并可作為輸入端
97、口。此時(shí),被外部拉低的P3口將用上拉電阻輸出電流()。 P3口除了作為一般的I/0口線外,更重要的用途是它的第二功能,。</p><p> 此外,P3口還接收一些用于Flash閃速存儲(chǔ)器編程和程序校驗(yàn)的控制信號(hào)。 </p><p> ·RST:復(fù)位輸入。當(dāng)振蕩器工作時(shí),RST引腳出現(xiàn)兩個(gè)機(jī)器周期以上高電平將使單片機(jī)復(fù)位。</p><p> ·
98、;ALE/:當(dāng)訪問(wèn)外部程序存儲(chǔ)器或數(shù)據(jù)存儲(chǔ)器時(shí),ALE(地址鎖存允許)輸出脈沖用于鎖存地址的低8位字節(jié)。一般情況下,ALE仍以時(shí)鐘振蕩頻率的l/6輸出固定的脈沖信號(hào),因此它可對(duì)外輸出時(shí)鐘或用于定時(shí)目的。要注意的是:每當(dāng)訪問(wèn)外部數(shù)據(jù)存儲(chǔ)器時(shí)將跳過(guò)一個(gè)ALE脈沖。</p><p> 對(duì)Flash存儲(chǔ)器編程期間,該引腳還用于輸入編程脈沖()。</p><p> 如有必要,可通過(guò)對(duì)特殊功能寄存
99、器(SFR)區(qū)中的8EH單元的D0位置位,可禁止ALE操作。該位置位后,只有一條MOVX和MOVC指令才能將ALE激活。此外,該引腳會(huì)被微弱拉高,單片機(jī)執(zhí)行外部程序時(shí),應(yīng)設(shè)置ALE禁止位無(wú)效。 </p><p> ·:程序儲(chǔ)存允許()輸出是外部程序存儲(chǔ)器的讀選通信號(hào),當(dāng)AT89S52由外部程序存儲(chǔ)器取指令(或數(shù)據(jù))時(shí),每個(gè)機(jī)器周期兩次有效,即輸出兩個(gè)脈沖。在此期間,當(dāng)訪問(wèn)外部數(shù)據(jù)存儲(chǔ)器,將跳過(guò)兩次信
100、號(hào)。</p><p> ·/VPP:外部訪問(wèn)允許。欲使CPU僅訪問(wèn)外部程序存儲(chǔ)器(地址為0000H—FFFFH),端必須保持低電平(接地)。需注意的是:如果加密位LB1被編程,復(fù)位時(shí)內(nèi)部會(huì)鎖存EA端狀態(tài)。如EA端為高電平(接Vcc端),CPU則執(zhí)行內(nèi)部程序存儲(chǔ)器中的指令。 Flash存儲(chǔ)器編程時(shí),該引腳加上+12V的編程允許電源Vpp,當(dāng)然這必須是該器件是使用12V編程電壓Vpp。</p>
101、<p> ·XTAL1:振蕩器反相放大器的及內(nèi)部時(shí)鐘發(fā)生器的輸入端。</p><p> ·XTAL2:振蕩器反相放大器的輸出端。</p><p> ·特殊功能寄存器:在AT89S52片內(nèi)存儲(chǔ)器中,80H-FFH共128個(gè)單元為特殊功能寄存器(SFR)。 并非所有的地址都被定義,從80H-FFH共128個(gè)字節(jié)只有一部分被定義,還有相當(dāng)一部分沒(méi)
102、有定義。對(duì)沒(méi)有定義的單元讀寫將是無(wú)效的讀出的數(shù)值將不確定,而寫入的數(shù)據(jù)也將丟失。不應(yīng)將數(shù)據(jù)“1”寫入未定義的單元,由于這些單元在將來(lái)的產(chǎn)品中可能賦予新的功能,在這種情況下,復(fù)位后這些單元數(shù)值總是“0”。</p><p> AT89S52除了與AT89C51所有的定時(shí)/計(jì)數(shù)器0和定時(shí)/計(jì)數(shù)器l外還增加了一個(gè)定時(shí)/計(jì)數(shù)器2。定時(shí)/計(jì)數(shù)器2的控制和狀態(tài)位位于T2CON。T2MOD寄存器對(duì)(RCA02H、RCAP2L)
103、是定時(shí)器2在16位捕獲方式或16位自動(dòng)重裝載方式下的捕獲/自動(dòng)重裝載寄存器。</p><p> ·中斷寄存器: AT89S52有6個(gè)中斷源,2個(gè)中斷優(yōu)先級(jí)IE寄存器控制各中斷位,IP寄存器中6個(gè)中斷源的每一個(gè)可定為2個(gè)優(yōu)先級(jí)。</p><p> 數(shù)據(jù)存儲(chǔ)器:AT89S52有256個(gè)字節(jié)的內(nèi)部RAM,80H-FFH高128個(gè)字節(jié)與特殊功能寄存器(SFR)地址是重疊的,也就是高1
104、28字節(jié)的RAM和特殊功能寄存器的地址是相同的,但物理上它們是分開的。 當(dāng)一條指令訪問(wèn)7FH以上的內(nèi)部地址單元時(shí),指令中使用的尋址方式是不同的,也即尋址方式?jīng)Q定是訪問(wèn)高128字節(jié)RAM還是訪問(wèn)特殊功能寄存器。如果指令是直接尋址方式則為訪問(wèn)特殊功能寄存器。 例如直接尋址指令訪問(wèn)特殊功能寄存器0A0H,即P2口地址單元。 </p><p> MOV 0A0H, #data </p><p>
105、 間接尋址指令訪問(wèn)高128字節(jié)RAM例如下面的間接尋址指令中R0的內(nèi)容為0A0H則訪問(wèn)數(shù)據(jù)字節(jié)地址為0A0H而不是P2口(0A0H)。</p><p> MOV @R0,#data</p><p> 堆棧操作也是間接尋址方式所以高128位數(shù)據(jù)RAM亦可作為堆棧區(qū)使用。</p><p><b> 紅外光</b></p>&
106、lt;p> 紅外(IR)是一種比可見光的波長(zhǎng)還長(zhǎng)的電磁輻射,從可見紅光在0.74 微米(µ米)的額定邊緣,傳統(tǒng)上延伸到了300微米。這些波長(zhǎng)對(duì)應(yīng)的頻率范圍大約1到400兆赫,其中包括大部分接近溫室的物體發(fā)出的熱輻射。顯微鏡下,通常情況下紅外光線的發(fā)射或吸收時(shí),它們就會(huì)改變其自己的旋轉(zhuǎn)振動(dòng)運(yùn)動(dòng)。 </p><p> 紅外線用于工業(yè)、科學(xué)和醫(yī)學(xué)應(yīng)用。夜視裝置使用紅外線照射,使沒(méi)
107、有被觀察者察覺(jué)人或動(dòng)物被檢測(cè)出來(lái)認(rèn)出。在天文學(xué)上,在紅外波段的成像可以觀察被星際塵埃遮擋的對(duì)象。紅外成像攝像機(jī)是用來(lái)檢測(cè)絕緣系統(tǒng)的熱損失,觀察皮膚中的血液流量的變化,和電氣設(shè)備的過(guò)熱。 </p><p> 大部分到達(dá)地球的太陽(yáng)能量來(lái)是以紅外輻射的形式。陽(yáng)光在天頂提供了一個(gè)發(fā)光超過(guò)1千瓦海平面每平方公尺。這種能量,527瓦茨是紅外輻射,445瓦茨是可見光,32瓦茨是紫外線輻射。紅外輻射的發(fā)射與吸收的平衡
108、對(duì)地球氣候有著重要作用。通常在物體跨波長(zhǎng)的頻譜發(fā)出的紅外輻射,但有時(shí)只有有限的頻譜的區(qū)域的是有益的,因?yàn)閭鞲衅魍ǔV辉谝粋€(gè)特定的帶寬手機(jī)輻射。因此,紅外波段常常是分成較小的部分。</p><p> 紅外輻射通常被稱為“熱量輻射”,但任何頻率的光,電磁波會(huì)發(fā)熱,吸收他們的表面。來(lái)自太陽(yáng)的紅外線光僅僅占49%對(duì)地球的加熱,其余的被吸收,然后是在較長(zhǎng)的波長(zhǎng)輻射的可見光引起的??梢姽饣蜃贤夤饩€紙和激光器能夠烘烤加熱熱物
109、體并發(fā)出可見輻射。在室溫條件下物體會(huì)發(fā)出大多集中在8-25微米波段的輻射,但這個(gè)是不可見光白熾燈對(duì)象和紫外線的排放量明顯的更熱的對(duì)象(見黑色的物體和維恩移定律)。</p><p> 熱是由于溫差的瞬態(tài)流動(dòng)而產(chǎn)生的能量。與傳輸熱量需要通過(guò)熱傳導(dǎo)或者通過(guò)熱對(duì)流不同,輻射是可以在真空中傳播的。 </p><p> 重要的是,了解對(duì)象的紅外輻射的發(fā)射率的概念問(wèn)題。這是一個(gè)表面,它描述
110、如何偏離理想黑體熱輻射的屬性。進(jìn)一步解釋,如果他們有不同的發(fā)射率,即使兩個(gè)物體有相同物理溫度的情況下也不會(huì)“呈現(xiàn)”相同的溫度下的紅外圖像。</p><p> 紅外輻射,可用于遠(yuǎn)程檢測(cè)的物體的溫度(若已知發(fā)射率)。這被稱為熱,或如非常熱的物體或可見它的情況下,它被稱為近紅外測(cè)溫方法。熱像儀(熱成像)主要用于軍事和工業(yè)應(yīng)用中,但技術(shù)已經(jīng)達(dá)到了在公開市場(chǎng)上大規(guī)模降低生產(chǎn)成本,比如汽車的紅外攝像機(jī)的形式。熱成像相機(jī)在紅
111、外檢測(cè)輻射范圍的電磁頻譜(大約900 - 14000納米或0.9-14微米),產(chǎn)生輻射的圖像。從紅外輻射物體發(fā)出的所有對(duì)象,基于他們的溫度,根據(jù)黑體輻射法、熱,使人們能夠“看到”一個(gè)人的環(huán)境中使用或不可見的照明。數(shù)隨溫度的對(duì)象增加所產(chǎn)生的熱輻量,因此熱像儀使人們能夠看到的溫差變化,(因此而得名)。 </p><p> 紅外輻射可以用來(lái)作為一個(gè)主動(dòng)供暖熱源。例如,用于熱紅外桑拿使用者
112、,并移除飛機(jī)翅膀上的冰(除冰)。遠(yuǎn)紅外輻射作為一種安全的天然保健理療的治療方法而受到歡迎和普及。紅外可用于燒飯和取暖,因?yàn)樗饕澄锛訜岵煌该鞯?、吸水性?qiáng)的物體,而不是他們周圍的空氣。 </p><p> 在工業(yè)生產(chǎn)過(guò)程,如固化涂料、成型鉚接、退火、塑料焊接、打印干燥中,紅外加熱也變得越來(lái)越受歡迎。在這些應(yīng)用中,紅外加熱器取代對(duì)流烤箱和接觸式的加熱。效率的獲得是通過(guò)匹配的波長(zhǎng)紅外加熱器,吸收特性的物質(zhì)
113、。 在氣候?qū)W領(lǐng)域,大氣紅外輻射檢測(cè),以發(fā)現(xiàn)地球和大氣之間的能量交換的趨勢(shì)為依據(jù)。這些趨勢(shì)對(duì)地球 氣候的長(zhǎng)期變化提供信息。它是在研究和探討全球變暖與太陽(yáng)輻射的主要參數(shù)之一。 </p><p> 利用一個(gè)地球輻射表為這一領(lǐng)域的研究進(jìn)行連續(xù)戶外測(cè)量。這是一個(gè)寬帶紅外輻射計(jì)與紅外輻射敏感性之間和50µm大約4.5µm。</p><p> 紅外線
114、夜視設(shè)備用于當(dāng)沒(méi)有足夠的可見光。夜視設(shè)備操作過(guò)程中涉及的環(huán)境光線的光子轉(zhuǎn)換成電子是由電氣,化學(xué)和過(guò)程,然后放大,然后轉(zhuǎn)換回可見光。紅外光源能被用來(lái)擴(kuò)大現(xiàn)有的環(huán)境光轉(zhuǎn)變?yōu)橐挂曆b置,增加黑暗中能見度,實(shí)際上并沒(méi)有使用可見光源。 熱成像基于表面溫度差異,通過(guò)檢測(cè)對(duì)象和周圍的環(huán)境產(chǎn)生的紅外輻射(熱)的基礎(chǔ)上創(chuàng)建的圖像,與紅外光夜視設(shè)備的使用不應(yīng)該混疊。</p><p> 天
115、文學(xué)家觀察物體的電磁頻譜紅外部分使用的光學(xué)部件,包括反射鏡、透鏡和固態(tài)數(shù)字探測(cè)器。因?yàn)檫@個(gè)原因,它被列為光學(xué)天文學(xué)的一部分。形成一個(gè)圖,像紅外望遠(yuǎn)鏡的部件必須仔細(xì)屏蔽熱源,探測(cè)器使用液態(tài)氦冷卻。 </p><p> 地面紅外望遠(yuǎn)鏡的敏感性明顯受制于在大氣中的水蒸氣,它吸收紅外輻射從太空到達(dá)選定的大氣窗口之外的部分。這種限制可以放置在高海拔天文臺(tái)的望遠(yuǎn)鏡,或者帶著望遠(yuǎn)鏡高空球囊或一架飛機(jī)??臻g望遠(yuǎn)鏡不受
116、這些障礙,使外層空間紅外天文學(xué)的理想位置。 在天文學(xué)家眼里,紅外光譜的部分有幾個(gè)有用的好處。寒冷,黑暗的分子的氣體云和塵埃在我們的銀河星系將閃耀著熱輻射,因?yàn)樗鼈兪歉畹俟痰男切恰<t外也可以被用來(lái)檢測(cè)恒星之前,他們開始發(fā)出可見光。恒星發(fā)出的紅外光譜一個(gè)較小的部分能量,他們的能量較小。所以附近的陰涼對(duì)象如行星可以更容易發(fā)現(xiàn)。(在可見光光譜,耀眼的球星將淹沒(méi)了從地球反射的光。)<
117、;/p><p> 紅外線光也可以用作觀察活躍星系的核心,而這些星系通常是被氣體和塵埃所籠罩的。遙遠(yuǎn)星系的紅色關(guān)柵偏移會(huì)有部分轉(zhuǎn)移其頻譜向波長(zhǎng)較長(zhǎng)的波峰,其波長(zhǎng)會(huì)變長(zhǎng),所以他們更容易在紅外中被觀察到。 </p><p> 紅外輻射被認(rèn)為是在19世紀(jì)早期被天文學(xué)家威廉·赫歇爾發(fā)現(xiàn)的。赫歇爾在1800年之前,在倫敦皇家學(xué)會(huì)上發(fā)表他的結(jié)果。赫歇爾利用三棱鏡折射太陽(yáng)的光線和檢測(cè)紅
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