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THE THERMAL BEHAVIOR OF TWO-COMPONENT PIEZOELECTRIC SINGLE CRYSTAL ALUMINIUM GALLIUM PHOSPHATE Al1-xGaxPO4
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The temperature properties of elastic, piezoelectric and dielectric constants for the single crystal Al0.88Ga0.12PO4 have been studied in detail over a temperature range from 150 to 410K. And two crystal plates with different orientations which have zero temperature coefficient are introduced. As might have been expected, the single crystal Al1-xGaxPO4 is a new kind of materials applicable to the surface acoustic wave devices. 相似文献
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本文分析了强激光作用下铝合金靶表面反射率的时间变化规律。利用转镜调Q钕玻璃激光器和积分球装置对铝LY12的表面激光反射率动态变化规律进行了测量,得到了功率密度在10 ̄6~10 ̄9W/cm ̄2范围内的相应结果。同时,从金属近自由电子模型-Drude理论出发,对金属铝的电导率与温度变化关系进行了数值模拟,亦得到了相应的反射率变化规律,实验结果与数值模拟结果基本符合。当激光功率密度更同时(10 ̄11~10 ̄15W/cm ̄2),由等离子体模型和局部热力学平衡(LTE)理论,得到了反射率随温度变化的数值模拟结果,与国外的实验结果符合得较好。 相似文献
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FORMATION OF A BURIED LAYER OF ALUMINIUM NITRIDE BY HIGH DOSE N2+ IMPLANTATION INTO ALUMINIUM
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Aluminium films with various thickness between 700 nm and 1μm were deposited on Si (100) substrates, and 400 keV N2+ ions with doses ranging from 4.3×1017 to 1.8×1018 N/cm2 were implanted into the alu-minium films on silicon, Rutherford Backscattering (RBS) and channeling, secondary ion mass spectroscopy (SIMS), Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and spreading resistance probes (SRP) were used to characterize the synthesized aluminium nitride. The experiments showed that when the implantation dose was higher than a critical dose Nc, a buried stoichiometric AlN layer with high resistance was formed, while no apparent AlN XRD peaks in the as-implanted samples were observed; however, there was a strong AlN(100) diffraction peak appearing after annealing at 500 ℃ for 1h. The computer program, Implantation of Reactive Ions into Silicon (IRIS), has been modified and used to simulate the formation of the buried AlN layer as N2+ is implanted into aluminium. We find a good agreement between experimental measurements and IRIS simulation. 相似文献
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When a consumed carbon anode in an aluminium electrolysis cell is replaced, the solid crust covering the anode and the bath is removed and transported in hopper cars to a cooling area where it remains for a period of one to four days, or more, to cool from a temperature of approximately 900°C to an acceptable temperature for autogenous milling, gas cleaning, product classification, and recycle to the process. This article addresses the possibility of processing the hot crust material more rapidly by using a separate or combined crushing/heat exchange system. Results of mechanical and thermal tests are presented and discussed. Mechanical tests demonstrated that it requires much less force to crush hot crust than cold crust samples. The thermal tests consisted of submitting both a single block and a bed of particles of the crust material to heating and cooling cycles to determine the convective heat transfer coefficient and the thermal diffusivity. The values obtained for the heat transfer coefficients were similar to those predicted by correlations, while the thermal diffusivity was larger than expected. Based on the results, a number of strategies to manage the crust material were proposed and analyzed from the perspectives of the plant conditions. Some of these options are briefly discussed and simulated. The results of the simulations indicate that in order to significantly reduce the cooling time, the size of the crust pieces should be reduced prior to cooling. 相似文献
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8—羟基喹啉铝的荧光老化机制 总被引:1,自引:0,他引:1
报导了8-羟基喹啉铝(Alq3)在紫外光照射下发生荧光猝灭的机制,测量了Alq3在光照射前后的紫外-可见吸收光谱、荧光光谱、红外吸收光电子能谱(XPS),分析了紫外光照射后Alq3分子结构变化,证明了产生结构变化的根源是中水与Alq3发生了化学反应,对Alq3的我老化机制提出了可能的解释。 相似文献
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石墨炉原子吸收法直接测定啤酒中铝 总被引:1,自引:0,他引:1
采用高速枪弹射击猪单后肢软组织,观察伤后远离原发伤道的血管内皮细胞的形态学变化,为远达效应的血流扰动学说提供实验资料。动物伤后6h解剖,大体见双肺下叶、左室后壁以及大脑的痛、腹侧面均有不同程度的血管破裂、出血,或毛细血管充血。光镜见猪主动脉弓内皮细胞有水肿,或脱落呈“鞋钵样”垂直悬吊在血管腔内;连续切片见内皮层有剥脱现象。 相似文献
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本文讨论了由作者首次人工合成的新的钨青铜结构铁电单晶(K0.20Na0.20Sr0.60Ba0.20)Nb2O6全部电弹常数的测量方法和测量程序。第一次发表了该晶体的全部电弹常数及电-机耦合系数等共53个数据。绝大多数的数据是按IRE标准进行测量的。采用了(zxl)45°切片的厚度切变振动模式和(xzt)45°棒的长度扩张模式来测定弹性系数s66D和s13D。对实验过程引起的测量误差进行了讨论。
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N2O/C2H2FAAS法测定铝的干扰研究 总被引:1,自引:1,他引:0
刺家平 《光谱学与光谱分析》1994,14(4):101-106
本文研究了40种单个无机离子、混和无机离子及24种有机物在N2O/C2H2火焰中对铝吸收信号的干扰情况。并从物理干扰、光谱干扰和化学干扰等角度对它们的干扰机理作了解释。 相似文献
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通过制备(YBa2Cu3O7)1-x(V2O5)x(0≤x≤0.15)复合材料,获得了一系列典型的弱连接的颗粒超导体,其中以dR/dT-T关系中呈现出双峰转变为主要特征。第一峰代表晶粒的超导转变,第二峰代表颗粒系统超导长程序的形成。对于具有双峰转变的样品,其临界电流密度一致地符合ic~(1-t)n,n=1.6.这一行为与三维Josephson结网络系统的渗流行为相一致;对于不具有双峰转变的系统,临界电流密度随温度的变化尽管也可以用jc~(1-t)n描述,但是幂指数n明显地大于1.6,且随样品的不同而离散地分布。本文还对产生这种离散的原因进行探索和分析。
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使用X射线单晶衍射法测定了Bi2Pb2V2O10的结构。该晶体属三斜晶系,空间群为C11-P1,单位晶胞内化学式数Z=1,晶胞参数为:a=7.084(4)?,b=7.278(3)?,c=5.587(3)?,α=111.91(5)°,β=95.01(6)°,γ=108.86(4)°,V=245.70?3,Dx=7.35g/cm3,μ(MoKα)=678,94cm-1,F(000)=456。用Patterson函数分析及Forier技术测定了结构,对原子坐标、各向同性及各向异性热参数进行了最小二乘方修正,R=0.079。结构分析表明,Bi2Pb2V2O10的Pb原子与O原子形成八角十二面体,Bi原子与O原子形成六角多面体。两个共棱的Pb—O多面体与两个共棱的Bi—O多面体相连,并沿bc平面无限延伸。讨论了吸收的影响。最后,将Bi2Pb2VO10的结构与Pb2SO5的结构进行了比较。
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POWDER NEUTRON DIFFRACTION STUDIES OF THE CRYSTALLOGRAPHIC AND MAGNETIC STRUCTURE OF Ho2Fe9Ga8 and Ho2Fe9Ga6AI2
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The crystallographic and magnetic structures of Ho2Fe9Ga8 and Ho2Fe9Ga6AI2 were studied by powder neutron diffraction at room temperature. The atom fractional occupancies of Ga and Al and the magnetic moments of Ho and Fe were obtained by using Rietveld analysis program. The magnetic structures of the two samples show an easy-axis anisotropy, with the Fe magnetic moment being ferrimagneticlly coupled to those of Ho. 相似文献
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用射频/直流磁控溅射法制备了CeO2/Nb2O5双层氧敏薄膜,利用X射线光电子能谱(XPS),描述并解释了单层CeO2薄膜中氧随温度变化的动力学行为,以及CeO2/Nb2O5薄膜界面对氧敏特性的影响.通过对Ce3d XPS谱的高斯拟合,计算了Ce3+浓度并给出了判定Ce4+还原的标志.结果表明,界面效应可以提高CeO2/Nb2O5薄膜中Ce4+的还原能力,使之远远高于单层CeO2薄膜,这对薄膜的氧敏特性是极为有利的.
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