共查询到20条相似文献,搜索用时 140 毫秒
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介绍了一种新型的光纤温度传感器,将它埋入复合材料试件中,可以测量出试件内部的温度变化。给出了理论推导,导出了条纹移动量与试件内部温度变化之间的关系。给出了实验装置和结果。 相似文献
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迈克尔孙干涉仪干涉条纹的数学表达式 总被引:3,自引:1,他引:2
把迈克尔孙干涉仪的干涉条纹看成是两个虚点光源在空间的干涉与屏幕的交线,进行适当的坐标变换后推导出屏幕上干涉条纹的数学方程。对各种情形下干涉条纹的形状以及随反光镜移动而引起的干涉条纹的移动进行了讨论。 相似文献
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在光的干涉实验中只要测出干涉条纹随金属温度变化的个数,进而求出金属长度随温度的变化量,在光的衍射实验中则利用衍射条纹的间距与缝宽之间的关系,通过测量衍射条纹的间距求出温度变化时待测金属的长度变化量,从而计算出待测金属的线胀系数。 相似文献
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基于空气劈尖干涉实验中,相邻两个级次干涉条纹所在位置处,在竖直方向上的空气层厚度差为二分之一波长,将移动读数显微镜测得的干涉条纹数据作为横坐标,由干涉条纹级次差确定的空气层厚度差作为纵坐标,进而对劈尖干涉仪中空气薄膜上表面与垂直于棱边平面的交线方程应用最小二乘法进行直线拟合,通过拟合得到的直线方程获取劈尖干涉仪所夹细丝... 相似文献
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为了可以实现对炮体表面瞬态温度分布变化的实时监测,同时克服传统瞬态高温测试仪器单点探测以及热惯性大等局限性,设计了基于散斑干涉与光谱频域分析相结合的瞬态温度分布测试系统。系统采用散斑干涉技术将炮体瞬态温度变化引发的微小形变转换成散斑干涉条纹,再由傅氏变换完成干涉条纹形变到光谱分布的函数转换,从而通过光谱分布函数反演任意采样时刻上的温度分布。实验采用ZX-FB1型光纤测温仪测试单点位置上瞬态温度作为标准值,再由555 nm激光器与面阵CCD采集散斑干涉条纹,分别使用图像识别法与傅氏变换法完成干涉条纹与瞬态温度的算法匹配,从而反演瞬态温度。实验结果显示,两种方法均能实现瞬态温度检测,但基于傅氏变换频谱分析的散斑干涉法精度更高,并且可以有效地克服由表面瑕疵、漆面磨损等问题造成的粗大误差。 相似文献
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为了给光锥与时间延迟积分电荷耦合器件耦合监控装置提供有效的被测运动条纹,分析了传统推扫成像实验装置的不足之处,设计了电子显示目标滚屏运动装置.采用光学相机对印刷条纹静止成像,并用TDI-CCD数字相机对监视器屏幕上的运动条纹动态成像.实验结果表明,该方案解决了高分辨率的鉴别率图样无法在监视器或投影仪上精确显示的困难.与传统的实验室模拟装置相比,该方案提高了鉴别率条纹的运动稳定性,减小了条纹运动速率与TDI-CCD扫描行频间的失配误差,不仅能够对耦合过程实施监控,而且还能用于耦合系统的像质评价. 相似文献
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Khokhlova VA Bailey MR Reed JA Cunitz BW Kaczkowski PJ Crum LA 《The Journal of the Acoustical Society of America》2006,119(3):1834-1848
The importance of nonlinear acoustic wave propagation and ultrasound-induced cavitation in the acceleration of thermal lesion production by high intensity focused ultrasound was investigated experimentally and theoretically in a transparent protein-containing gel. A numerical model that accounted for nonlinear acoustic propagation was used to simulate experimental conditions. Various exposure regimes with equal total ultrasound energy but variable peak acoustic pressure were studied for single lesions and lesion stripes obtained by moving the transducer. Static overpressure was applied to suppress cavitation. Strong enhancement of lesion production was observed for high amplitude waves and was supported by modeling. Through overpressure experiments it was shown that both nonlinear propagation and cavitation mechanisms participate in accelerating lesion inception and growth. Using B-mode ultrasound, cavitation was observed at normal ambient pressure as weakly enhanced echogenicity in the focal region, but was not detected with overpressure. Formation of tadpole-shaped lesions, shifted toward the transducer, was always observed to be due to boiling. Boiling bubbles were visible in the gel and were evident as strongly echogenic regions in B-mode images. These experiments indicate that nonlinear propagation and cavitation accelerate heating, but no lesion displacement or distortion was observed in the absence of boiling. 相似文献
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Thermal characteristics of multiple laser stripes integrated into one chip is investigated theoretically in this paper. The temperature pattern of the laser diode mini-array packaged in a TO-can is analyzed and optimized to achieve a uniform temperature distribution among the laser stripes and along the cavity direction. The temperature among the laser stripes varies by more than 5 K if the stripes are equally arranged, and can be reduced to less than 0.4 K if proper arrangement is designed. For conventional submount structure, the temperature variation along the cavity direction is as high as 7 K, while for an optimized trapezoid submount structure, the temperature varies only within 0.5 K. 相似文献
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Tom Hosiawa 《Journal of magnetism and magnetic materials》2009,321(12):1878-1884
Magnetic domain structures are a fascinating area of study with interest deriving both from technological applications and fundamental scientific questions. The nature of the striped magnetic phases observed in ultra-thin films is one such intriguing system. The non-equilibrium dynamics of such systems as they evolve toward equilibrium has only recently become an area of interest and previous work on model systems showed evidence of complex, slow dynamics with glass-like properties as the stripes order mesoscopically. To aid in the characterization of the observed phases and the nature of the transitions observed in model systems we have developed an efficient method for identifying clusters or domains in the spin system, where the clusters are based on the stripe orientation. Thus we are able to track the growth and decay of such clusters of stripes in a Monte Carlo simulation and observe directly the nature of the slow dynamics. We have applied this method to consider the growth and decay of ordered domains after a quench from a saturated magnetic state to temperatures near and well below the critical temperature in the 2D dipolar Ising model. We discuss our method of identifying stripe domains or clusters of stripes within this model and present the results of our investigations. 相似文献
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Study of the temperature rise induced by a focusing transducer with a wide aperture angle on biological tissue containing ribs
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We used the spheroidal beam equation to calculate the sound field created by focusing a transducer with a wide aperture angle to obtain the heat deposition, and then we used the Pennes bioheat equation to calculate the temperature field in biological tissue with ribs and to ascertain the effects of rib parameters on the temperature field. The results show that the location and the gap width between the ribs have a great influence on the axial and radial temperature rise of multilayer biological tissue. With a decreasing gap width, the location of the maximum temperature rise moves forward; as the ribs are closer to the transducer surface, the sound energy that passes through the gap between the ribs at the focus decreases,the maximum temperature rise decreases, and the location of the maximum temperature rise moves forward with the ribs. 相似文献
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Misuzu Sagawa 《Optical Review》1996,3(6):518-527
180° mode phased array lasers with multiple stripes were systematically investigated for high-power, single lateral mode operation. Phased array lasers with a conventional loss guide structure were fabricated for 180° mode operation because the structure allowed the threshold gain of 180° mode to become smallest by introducing optical loss between stripes and outside the stripe region. It showed complete single lateral mode operation under pulsed condition. However, under continuous wave operation, phase-uncoupling occurred at the edge emitters as a result of the temperature distribution inside the stripe region. This was confirmed both experimentally and theoretically. To minimise the temperature distribution, dummy stripes were introduced outside the stripe region. The current in the dummy stripes did not cause lasing, but did increase the temperature of the edge stripes, which improved the thermal distribution inside the stripe region. As a result, complete single lateral 180° mode operation under continuous wave operation was attained. 相似文献
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We study here the onset of charge density wave instabilities in quantum Hall systems at finite temperature for Landau level filling nu>4. Specific emphasis is placed on the role of disorder as well as on an in-plane magnetic field. Beyond some critical value, disorder is observed to suppress the charge density wave melting temperature to zero. In addition, we find that a transition from perpendicular to parallel stripes (relative to the in-plane magnetic field) exists when the electron gas thickness exceeds approximately 60 A. The perpendicular alignment of the stripes is in agreement with the experimental finding that the easy conduction direction is perpendicular to the in-plane field. 相似文献
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de la Figuera J Léonard F Bartelt NC Stumpf R McCarty KF 《Physical review letters》2008,100(18):186102
We observe using low-energy electron microscopy the self-assembly of monolayer-thick stripes of Au on W(110) near the transition temperature between stripes and the nonpatterned (homogeneous) phase. We demonstrate that the amplitude of this Au-stripe phase decreases with increasing temperature and vanishes at the order-disorder transition (ODT). The wavelength varies much more slowly with temperature and coverage than theories of stress-domain patterns with sharp boundaries would predict, and maintains a finite value of about 100 nm at the ODT. We argue that such nanometer-scale stripes should often appear near the ODT. 相似文献
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The plasmon microwave response of symmetric and asymmetric stripes of two-dimensional electrons with different boundary conditions
has been studied. The symmetric case corresponds to stripes either without ohmic contacts or with ohmic contacts on both sides,
while the contact in asymmetric stripes is present only on one side. It has been shown that there is a frequency shift of
the observed plasma modes in asymmetric stripes. The lowest-frequency mode becomes a previously unobserved mode for which
the quarter wavelength of the plasmon coincides with the length of the stripe. The behavior of the lowest mode and its multiple
frequencies in asymmetric stripes has been studied under variation of the magnetic field, electron density, and temperature
and size of the stripes. The results indicate that all plasma modes in symmetric and asymmetric stripes have the same physical
nature. 相似文献