共查询到20条相似文献,搜索用时 31 毫秒
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基于金属电子气模型,进行了温度、压力对Au反射率变化影响的研究与分析。利用DAC装置开展了压力对Au反射率变化测量实验,以及激光加热的动态温升条件下温度对Au反射率变化测量实验,获得了探测光束波长为488 nm条件下,温度(室温至350 ℃)和压力(11 GPa范围内)对Au反射特性影响的实验结果。结果表明:在11 GPa压力范围内,与温度因素相比,压力对Au的反射率变化影响可忽略;Au对488 nm波长激光的反射率变化趋势为单调递增,变化幅值达约10%,且具有反射率与温度的一一对应特性。通过动高压加载下材料温度瞬态测量要求分析,认为基于Au在488 nm波长下的反射变化特性,可建立一种适用于动高压加载下低温段(低于1000 K)的瞬态测温方法,用于解决材料动高压领域的瞬态测温技术难点。 相似文献
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高温下正十五烷的拉曼光谱研究 总被引:2,自引:1,他引:1
文章在金刚石压腔下研究了正十五烷从室温到350℃的拉曼光谱特征.结果表明:随着温度的升高,体系压力也在不断增大;CH3,CH2对称和反对称伸缩振动同时受到温度和压力的影响,但2种作用相反.由于压力效应大于温度效应,随温度压力的增大CH3,CH2对称和反对称伸缩振动的拉曼位移均向高频方向移动,说明C-H键键能在增大.另外,由于新物质的生成导致过强荧光产生而无法测出正十五烷的拉曼光谱,而且过强荧光出现的时间早晚与温度和压力有一定的关系. 相似文献
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压力与温度双参量传感优化系统的研制 总被引:7,自引:0,他引:7
研究了一种基于管式弹性应变敏感元件的光纤光栅传感器结构。利用双光纤布拉格光栅(FBG)产生双反射峰.对压力和温度进行了同时区分测量。在压力为0~20MPa,温度为20~150℃的范围内,布拉格反射波长对应压力与温度的变化均呈现良好的线性响应特性,响应灵敏度分别为0.089nm/MPa和0.024nm/C^-。压力温度双参量系数矩阵的实验拟合值与理论计算值之差仅占理论计算值的1.8%。该方法与标准测量方法比较,压力的准确度为0.47%;温度的准确度为0.74%。该方法还较好地削减了压力与温度交叉敏感的影响,按压力与温度测量的最大量限计算,温度对压力交叉影响的误差仅为0.16%。 相似文献
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In the present study, a thermodynamic model is formulated to determine the melting temperature of metals with increasing pressure using an equation of state (EoS). The model is applied to determine the melting temperature of Cu, Au, Ag, Zn, Cd, In and Pb at high pressure. The model formulation is based on Goyal and Gupta EoS which follows Stacey's criteria and is valid in high pressure conditions and also it does not involve any adjustable parameter. The volume compression, bulk modulus and its first order pressure derivative is determined using the EoS with an increase in pressure. It is observed that melting temperature show increase with the increase in pressure, however, variation is not linear. The comparison of present computed results of melting temperature under pressure is done with the theoretical and experimental results available and good consistency between the compared results is observed. This study helps in understanding the quantitative effect of pressure on the melting behavior of metals. The melting temperature at high pressures can also be predicted using the present formalism. 相似文献
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气体压力光学非接触测量是目前激光技术重要应用领域之一,其中气压测量过程中温度耦合问题是现在面临的研究难点。故而提出一种光谱测量技术与激光干涉技术组合测量方法,通过积分吸光度和折射率融合的方式实现气体压力、温度解耦的目的。分析可调谐半导体激光光谱技术(TDLAS)的直接吸收法测量原理和基于折射率的激光干涉测量原理,建立基于吸收光谱的气压测量模型和基于折射率的激光干涉气压测量模型,通过利用三次多项式拟合吸收谱线强度函数的方式,建立了基于积分吸光度和折射率的气体压力、温度解耦的数学模型。实验搭建了基于TDLAS技术和激光干涉技术的气体压力检测系统,采用中心波长为2 004 nm的可调谐半导体激光器和波长为632.8 nm的激光干涉仪,气室长度为24.8 cm,将CO2作为研究对象,并以高精度压力控制器和温度传感器的测量结果分别作为压力温度参考值,以真空为背景信号,在室温环境中测量并计算出气体压力变化后积分吸光度值和折射率值,进而解算得到气体压力和温度值。实验结果显示:压力测量结果最大相对误差为3.61%,最小相对误差为0.5%,测量平均相对误差为1.99%;在以开尔文温度为前提下,温度解算结果最大绝对误差为7.66 K,最小绝对误差为0.78 K,测量平均绝对误差为3.29 K,测量结果与参考结果具有较高的吻合度,该研究可为以后光学法测量气体压力温度影响分析提供参考。 相似文献
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Thermodynamic properties of Cd0.25Zn0.75Se alloy are studied using quasi harmonic model for pressure range of 0 GPa-10 GPa and temperature range 0 K-1000 K. The structural optimization is obtained by self-consistent field calculations and full-potential linearized muffin-tin orbital method with GGA+U as an exchange correlation functional where U=2.3427 eV is Hubbard potential. The effects of temperature and pressure on bulk modulus, Helmholtz free energy, internal energy, entropy, Debye temperature, Grüneisen parameter, thermal expansion coefficient, and heat capacities of the material are observed and discussed. The bulk modulus, Helmholtz free energy, and Debye temperature are found to be decreased on increasing temperature while there is an increasing behavior with rise of the pressure. Whereas the internal energy has increasing trend with the rise in temperature and it almost remains insensitive to pressure. The entropy of the system increases (decreases) with rise of pressure (temperature). 相似文献
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为了实现油田井下温度压力的全分布式测量,提出了一种基于光纤散射原理的分布式温度压力测量方法。该方法通过对普通光纤进行封装设计,制作成传感光纤。由于光纤传感器周围流体的温度和压力会对传感光纤内的散射光产生调制作用,通过光纤解调仪解调出光纤拉曼散射参数和布里渊散射频移就能够实现温度和压力的实时在线测量。实验结果表明:设计的分布式光纤温度压力传感器可以实现的温度测量分辨率为0.1 ℃,压力测量分辨率为0.07 MPa。基本满足油田井下温度压力测量的全分布式、实时在线、可靠性高、精度高、抗干扰能力强等要求。 相似文献
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293~563 K下甲醇结构的研究 总被引:2,自引:1,他引:1
利用金刚石压腔和拉曼光谱,研究了甲醇从室温到563 K下的结构特征。结果表明:随着温度的升高,体系压力也在不断增大;νCH区伸缩振动和νOH区伸缩振动同时受到温度和压力的影响,但两种作用相反。由于压力效应大于温度效应,随温度压力的增大,νCH区伸缩振动的拉曼位移向高频方向移动,说明C—H键键能在增大;而O—H伸缩振动峰的相对面积随温度压力的增大而增大,说明对C—H键而言,O—H键总强度是增加的,由此推测在地质条件下,压力可能阻碍或延长了干酪根的降解生烃过程。 相似文献
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用于彩色滤光片的低阻低应力ITO透明导电膜 总被引:2,自引:0,他引:2
探讨了用于彩色滤光片的低电阻和低压应力的ITO透明导电膜工艺。用磁控溅射方法在不同温度的衬底上制备了ITO薄膜。研究了膜形衬底温度与膜结晶化程度的关系,以及膜形衬底温度对膜电阻和压应力的影响。对不同衬底温度下形成的ITO薄膜进行了退火处理,并对退火后的ITO薄膜的电阻和压应力特性进行了分析。结果表明,采用室温沉积非晶态ITO膜,在真空退火下可获得低电阻、低压应力的多晶相ITO膜。 相似文献
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Zhen Zhou Francisco E. Hernández-Pérez Yuriy Shoshin Jeroen A. van Oijen Laurentius P.H. de Goey 《Combustion Theory and Modelling》2017,21(5):879-896
The influence of Soret diffusion on lean premixed flames propagating in hydrogen/air mixtures is numerically investigated with a detailed chemical and transport models at normal and elevated pressure and temperature. The Soret diffusion influence on the one-dimensional (1D) flame mass burning rate and two-dimensional (2D) flame propagating characteristics is analysed, revealing a strong dependency on flame stretch rate, pressure and temperature. For 1D flames, at normal pressure and temperature, with an increase of Karlovitz number from 0 to 0.4, the mass burning rate is first reduced and then enhanced by Soret diffusion of H2 while it is reduced by Soret diffusion of H. The influence of Soret diffusion of H2 is enhanced by pressure and reduced by temperature. On the contrary, the influence of Soret diffusion of H is reduced by pressure and enhanced by temperature. For 2D flames, at normal pressure and temperature, during the early phase of flame evolution, flames with Soret diffusion display more curved flame cells. Pressure enhances this effect, while temperature reduces it. The influence of Soret diffusion of H2 on the global consumption speed is enhanced at elevated pressure. The influence of Soret diffusion of H on the global consumption speed is enhanced at elevated temperature. The flame evolution is more affected by Soret diffusion in the early phase of propagation than in the long run due to the local enrichment of H2 caused by flame curvature effects. The present study provides new insights into the Soret diffusion effect on the characteristics of lean hydrogen/air flames at conditions that are relevant to practical applications, e.g. gas engines and turbines. 相似文献
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We developed a dual-luminophor pressure/temperature sensitive paint (DPTSP) to correct the temperature dependence of pressure-sensitive
paint. The DPTSP is composed of two sensor molecules, PtTFPP and Rhodamine B (RhB), and Poly-IBM-co-TFEM as a binder. Temperature
was determined from the image of RhB, and the temperature dependence of PtTFPP was corrected using the calculated temperature.
To validate the capability of DPTSP for temperature correction, the pressure field on a delta wing model was measured by the
DPTSP measurement system. The pressure values obtained with DPTSP were in good quantitative agreement with pressure tap data.
It has been validated that DPTSP is effective in correcting the temperature dependence of PSP. 相似文献
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《Solid State Ionics》2006,177(26-32):2687-2690
High pressure conductivity measurements have been carried out on P(EO)20LiBETI from 295 K to 368 K. The decrease of electrical conductivity with pressure is larger in the partially crystalline phase (low temperature and low pressure or high temperature and high pressure) than in the fully amorphous phase (high temperature and low pressure). It is found that if the phase transition is approached from the crystalline phase (decreasing pressure), the pressure of the phase transition varies from 0 to 0.23 GPa as the temperature increases from 336 K to 358 K. The shift of the phase transition temperature with pressure is approximately the same as the shift of the glass transition temperature with pressure for pure PEO. This can be understood in terms of the defect diffusion model. If the material is above 336 K and is in the fully amorphous phase, after pressure is increased above the critical pressure, the material remains in the amorphous phase for extended periods of time before transforming to the partially crystalline phase. This is reminiscent of a super-pressed state but may be an indication of slow crystallization kinetics. 相似文献
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提出了一种在高温环境下同时测量温度和气压的光子晶体光纤温度压力传感器.在普通单模光纤和光子晶体光纤之间熔接一段空心光纤构成干涉结构.空心光纤段构成非本征法布里-珀罗干涉仪,利用光子晶体光纤的微孔与外界相通,通过气体折射率变化来测量环境中的气压变化;光子晶体光纤段构成本征法布里-珀罗干涉仪,利用热膨胀效应和热光效应来测量环境中的温度.传感器的解调通过自制的白光干涉解调仪实现,实验通过测量腔长得到被测环境的温度和气压.在不同温度和气压环境下,对腔长分别为306μm和1535μm的温度压力光纤传感器进行连续测量.实验结果表明,传感器能够在28~800℃的温度下和0~10 MPa的气压下稳定工作,测量范围内温度灵敏度可达17.4 nm/℃,压力灵敏度随温度增加而降低,在28℃时可达1460.5 nm/MPa. 相似文献
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The paper provides a comprehensive molecular dynamics study of nanostructures compressed by a system of surface atoms to analyze their surface tension. Surface tension is here understood as phenomena resulting from the presence of surface atoms. All main properties of nanostructures are conditioned by a highly developed surface. The number of surface atoms and their energy are comparable to those of bulk atoms.It is shown that at cryogenic temperatures, spherical solid-state clusters of size up to 10 nm reveal excess pressure. This pressure owes to compression of the clusters by surface atoms.The molecular dynamics study of thermodynamic properties of the nanostructures demonstrates that the increase in pressure in clusters of size from 2 to 9 nm with temperature is due to the gas component and the slope on the temperature dependence of thermal pressure does not depend on the cluster size. It is also shown that the surface tension coefficient decreases with an increase in temperature. A theoretical expression for this dependence is derived suggesting that there exists a certain Laplace temperature at which compressive pressure in a cluster is balanced by thermal gas pressure. 相似文献