本文選題：鑭錳氧化物 + 鍶摻雜　； 參考：《安徽工業(yè)大學(xué)》2017年碩士論文

【摘要】：摻雜型鑭錳氧化物由于具有金屬-絕緣相轉(zhuǎn)變現(xiàn)象,使其發(fā)射率呈現(xiàn)自主變化特性,從而受到研究者們的廣泛關(guān)注。金屬-絕緣相變屬于二級相變,不伴隨熱量的吸收與釋放,其發(fā)射率的自主變化需要借助外場能量發(fā)生。然而遺憾的是,至今未見有將外場作用于鑭錳氧化物研究其發(fā)射率變化的報道�；诖�,本文選擇鍶摻雜的鑭錳氧化物作為研究對象,采用紅外輻射場與鑭錳氧化物相互作用,利用X射線衍射分析、掃描電鏡、紅外吸收光譜、電子自旋共振等現(xiàn)代分析手段,探索了鑭錳氧化物的組成、結(jié)構(gòu)與發(fā)射率之間的對應(yīng)關(guān)系,揭示了其發(fā)射率與紅外輻射場的響應(yīng)特性與規(guī)律。得出結(jié)論如下:1.為了克服輻射場引起的發(fā)射率測試結(jié)果偏差,在現(xiàn)有發(fā)射率測試系統(tǒng)的基礎(chǔ)上設(shè)置了輻射場系統(tǒng)和溫度控制系統(tǒng)。本裝置結(jié)構(gòu)簡單、成本低廉,能夠顯著降低樣品與標(biāo)準(zhǔn)體的溫差,從而有效降低發(fā)射率測試結(jié)果偏差。2.無外場作用下,摻Sr后樣品的晶體沿a、b軸收縮,沿c軸膨脹,使得樣品表現(xiàn)出(104)晶面擇優(yōu)取向,這可能是樣品發(fā)射率降低的原因之一。不同形貌樣品發(fā)射率的大小順序為:塊狀球狀片狀。隨著Sr的摻雜,樣品晶體完整性增強(qiáng),晶格振動需要更高的能量,其Mn O鍵吸收峰向短波方向偏移,且x=0.3樣品的吸收峰明顯弱于其他樣品,發(fā)射率表現(xiàn)出最小值。3.紅外輻射場作用下,樣品晶格結(jié)構(gòu)對稱性隨溫度升高而提高,穩(wěn)定性增強(qiáng);且x=0.2樣品有向立方相轉(zhuǎn)變的趨勢,其鐵磁性也增強(qiáng)。由于Mn-O、MnO-Mn和La位表面振動,與2.5~500μm波段輻射場形成共振,因此樣品在2.5~500μm輻射場下的溫度高于0.76~2.5μm下的溫度。且相同條件下的發(fā)射率與波長成正比,因此樣品在2.5~500μm下的發(fā)射率也較高。而x=0.2樣品在照射時間20s時,2.5~500μm下的發(fā)射率卻較低;且在0.76~2.5μm下的發(fā)射率基本不變,在2.5~500μm下的發(fā)射率增長幅度較大,達(dá)到23%。導(dǎo)致這一現(xiàn)象的原因,可能與晶格振動與輻射波的共振吸收,以及摻雜樣品x=0.2時的金屬絕緣相變發(fā)生的溫度位置有關(guān)。樣品發(fā)射率在輻射場和同溫度場下均呈現(xiàn)升高趨勢。然而,樣品在輻射場下的發(fā)射率大于在溫度場下的發(fā)射率。原因可能是輻射場下發(fā)射率上升是由兩個因素導(dǎo)致的:一是輻射導(dǎo)致的溫度升高;二是輻射導(dǎo)致的樣品內(nèi)部晶格振動變化。4.晶格振動和能級躍遷對輻射場下樣品發(fā)射率的影響較為顯著,而傳播過程的影響相對較小。樣品晶格結(jié)構(gòu)不同,共振吸收的波段發(fā)生變化,從而影響發(fā)射率。樣品內(nèi)部的能級躍遷,影響對光能的吸收,從而與晶格振動共同作用,影響發(fā)射率。輻射距離相等條件下,輻射波段對樣品發(fā)射率的影響不大。
[Abstract]:Doping lanthanum manganese oxide has been widely concerned by researchers because of its metal-insulating phase transition, which makes its emissivity change independently. The metal-insulating phase transition is a second-order phase transition, which is not accompanied by the absorption and release of heat. The independent change of emissivity needs to be generated by external field energy. However, unfortunately, there are no reports of the external field acting on lanthanum manganese oxide to study the emissivity of lanthanum manganese oxide. In this paper, strontium doped lanthanum manganese oxide is chosen as the object of study. The infrared radiation field and lanthanum manganese oxide interaction are adopted, and X-ray diffraction analysis, scanning electron microscope and infrared absorption spectrum are used. The relationship between the composition, structure and emissivity of lanthanum manganese oxide has been explored by means of electron spin resonance, and the response characteristics and laws of its emissivity and infrared radiation field have been revealed. The conclusion is as follows: 1. In order to overcome the emissivity error caused by radiation field, the radiation field system and temperature control system are set up on the basis of the existing emissivity measurement system. The device is simple in structure and low in cost, and can significantly reduce the temperature difference between the sample and the standard body, thus effectively reducing the deviation of the emissivity test results. Without external field, the crystal of Sr-doped sample shrinks along the aqb axis and expands along the c-axis, which makes the sample exhibit a preferred orientation of the crystal plane of 104), which may be one of the reasons for the decrease of the emissivity of the sample. The order of emissivity of different morphologies is as follows: block globular flake. With Sr doping, the crystal integrity of the sample is enhanced, and the lattice vibration needs higher energy. The absorption peak of mn / O bond shifts to the shortwave direction, and the absorption peak of xn0.3 sample is obviously weaker than that of other samples, and the emissivity shows the minimum value of .3. Under the action of infrared radiation field, the symmetry of lattice structure increases with the increase of temperature, and the stability of the sample is enhanced, and the ferromagnetism of the sample x0. 2 has the tendency of transition to cubic phase. Due to the surface vibration of Mn-O _ (-O) -MnO-Mn and La sites, which resonates with the radiation field at 2.5 渭 m band, the temperature of the sample is higher than the temperature of 0.76 ~ (2.5 渭 m) at 2.5 ~ 500 渭 m radiation field. Under the same conditions, the emissivity is proportional to the wavelength, so the emissivity of the sample at 2.5 渭 m is higher. However, the emissivity of XG 0.2 sample is low at 2.5 渭 m for 20 s, and the emissivity at 2.5 渭 m at 0.76 渭 m is almost unchanged, and the emissivity increases greatly at 2.5 渭 m, reaching 23%. The reason for this phenomenon may be related to the resonance absorption of lattice vibration and radiation wave, and the temperature position of the metal insulation phase transition of doped sample x = 0.2. The emissivity of the sample increases under both the radiation field and the same temperature field. However, the emissivity of the sample in the radiation field is greater than that in the temperature field. The reason may be that the rise of emissivity under radiation field is caused by two factors: one is the temperature rise caused by radiation and the other is the lattice vibration change of sample induced by radiation. The effect of lattice vibration and energy level transition on the emissivity of the sample under radiation field is significant, but the influence of the propagation process is relatively small. The band of resonance absorption varies with the lattice structure of the sample, which affects the emissivity. The energy level transition in the sample affects the absorption of light energy, which, together with the lattice vibration, affects the emissivity. When the radiation distance is equal, the radiation band has little effect on the emissivity of the sample.
【學(xué)位授予單位】：安徽工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O611.62

【參考文獻(xiàn)】

相關(guān)期刊論文 前7條

1 范德松;李強(qiáng);宣益民;;熱致變色材料輻射和光學(xué)特性研究[J];工程熱物理學(xué)報;2011年08期

2 葉曉云;周鈺明;陳丁桂;肖雪清;;不同形貌氧化鋅的紅外發(fā)射率研究[J];福建工程學(xué)院學(xué)報;2009年06期

3 李強(qiáng);匡柳;宣益民;;熱致變色可變發(fā)射率材料的制備與輻射特性研究[J];工程熱物理學(xué)報;2009年06期

4 劉俊明,王克鋒;稀土摻雜錳氧化物龐磁電阻效應(yīng)[J];物理學(xué)進(jìn)展;2005年01期

5 施德恒,劉玉芳,孫金鋒,黃國慶,陳玉科;反射輻射和探測器本身的輻射對實時測溫系統(tǒng)測溫精度的影響及其抑制[J];中國激光;2004年01期

6 黃良甫,賈付云;空間微機(jī)電系統(tǒng)的研究與進(jìn)展[J];真空與低溫;2002年04期

7 戴道生,熊光成,吳思誠;RE_(1-x)T_xMnO_3氧化物的結(jié)構(gòu),電磁特性和巨磁電阻[J];物理學(xué)進(jìn)展;1997年02期

相關(guān)博士學(xué)位論文 前2條

1 申星梅;摻雜型鑭錳氧化物的制備及其紅外發(fā)射率研究[D];南京航空航天大學(xué);2010年

2 王高;窄脈沖激光波長測試技術(shù)研究[D];中北大學(xué);2005年

，

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