共查询到17条相似文献,搜索用时 58 毫秒
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为了进一步提高全量程气体超声流量计的测量精度,基于多通道声波到时和实时温度,提出了一种交叉分段差分进化(Differential Evolution)支持向量回归(Support Vector Regression)DE-SVR模型。考虑到气体在不同流量条件下的流体状态不同,提出了交叉分段处理的方法,采用DE算法优化选取SVR参数。实验结果表明,对于16~1600m3/h全量程,交叉分段DE-SVR和传统积分方法计算气体流量的平均相对误差分别为0.00447和0.02781,前者较后者降低了83.93%;对于16~160m3/h小流量,交叉分段DE-SVR和无分段DE-SVR算法计算结果平均相对误差分别为0.00436和0.03214,前者较后者降低了86.43%。该方法有效避免了声道长度、探头角度以及管道直径等参数不确定性对流量计算的影响,为全量程气体流量的高精度测量提供了保障。 相似文献
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化学计量学速差动力学光谱法同时测定盐酸氯丙嗪和盐酸异丙嗪 总被引:6,自引:2,他引:6
盐酸氯丙嗪和盐酸异丙嗪在适当的硫酸介质中均能被硫酸铈铵快速氧化成红色化合物,该化合物又逐步被氧化成无色物质,两种药物的动力学过程的差异较小,动力学曲线相似。采集10~180 s动力学光谱数据,用主成分回归法(PCR)和偏最小二乘法(PLS)处理所测得的光谱动力学数据,建立了化学计量学速差动力学光度法同时测定该两种药物的新方法。盐酸氯丙嗪和盐酸异丙嗪的线性范围分别为8.3~66.7 mg·L-1和3.3~26.7 mg·L-1,检出限分别为2.32 mg·L-1和0.95 mg·L-1。该法用于药物针剂和片剂的测定,结果良好。 相似文献
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一种可视化DSC装置的设计与校准 总被引:1,自引:0,他引:1
设计研制了一种具有可视化功能的差示扫描量热装置,简称可视化DSC装置。该可视化DSC装置能够在差示扫描测量的同时,通过配套使用的显微镜摄像系统对测试样品的微观结构变化进行观察并记录。采用纯水为标准物质,对可视化DSC装置的温度测量与热量测量分别进行了校准,结果表明具有较高的测量稳定性。该可视化DSC装置能同时提供测试样品的热效应数据和微观结构的图像数据,提高了数据获取的同步性与测量结果的准确性。 相似文献
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本文是差谱法的一个应用实例。以盐酸羟胺为还原剂,用柠檬酸钠掩蔽A1(Ⅲ)以防止生成氢氧化铝沉淀。在PH值8.3-9.5下,Cu(Ⅰ)及Fe(Ⅱ)能与邻菲罗啉生成有色络合物,加热能大大加快显色时间,在乙醇存在下可使Cu(Ⅰ)络合物至少稳定5小时,方法简便、准确。 相似文献
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为获取液体介质的声速值,设计了一种测定流体声速的实验方法,该方法利用时差式超声波流量计和标准流量校验设备同时对封闭管道中的液体进行流速测量,分别得到流速的测量值和真实值,从而计算出超声波流量计的仪表系数,并以此导出了一定条件下液体介质的声速值随仪表系数的变化关系式.利用该方法测量给出了0.17 MPa下四氧化二氮(N2O4)在7.6-19.4 ℃、偏二甲肼((CH3)2NNH2)在6.5-25.2 ℃范围内的流体声速值,并为其他液体介质的声速测量提供了借鉴.
关键词:
超声波流量计
声速
仪表系数
温度 相似文献
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Acoustic test objects are commonly used for quality assurance testing of diagnostic ultrasound machines. However, the accompanying calibration protocols rely heavily on the judgment of the sonographer, are dependent on machine settings and are semi-quantitative. In the current study, two unique test objects and protocols were designed to quantitatively determine diagnostic ultrasound parameters, namely axial resolution and geometric uniformity, and lateral resolution and geometric uniformity of the ultrasound field. The effect of focal zone, signal gain, and distance from the ultrasound probe on these parameters was assessed. The investigation was performed using a typical low-frequency diagnostic unit equipped with a 7.5 MHz linear pulse–echo probe. Results underline the need to ensure that sensitivity of routine testing regimes is adequate for the measurements to be made. This study is a preliminary part of a larger project developing an ultrasound technique to be used as an engineering design tool in a non-clinical industrial setting for quality assurance testing of total knee replacements immersed in water. 相似文献
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In the camera calibration using translational planar object instead of 3D target, the skew affected by the imprecision in installation causes the object to deviate from the designated position, which produces errors to the world coordinates of control points and reduces the calibration accuracy. In this paper, a skew correction model is established to correct this skew. We note and prove that the skew bias of control point which is close to the fix point is tiny. According to the projection regulation, the pixel distance between two adjacent control points which is close to the fix point in skewed situation is a value extremely approximate to that in the ideal situation. Based on this property, we utilize the pixel distance to assign the image coordinates based on the fix point. The assigned values are then employed to estimate the skew factors, by which the initial camera parameters are optimized and lens distortion in the calibration images are corrected. This process is then repeated until convergence. Experiments based on real images prove that this method is more accurate than other methods without correcting skew. The parameters obtained by our method can be applied to the 3D reconstruction directly and effectively. 相似文献
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采用漫反射板法定标成像光谱仪是近年来发展起来的一种辐射定标新技术,它具有实现容易、定标精度较高的特点。文章根据漫反射板定标法的原理,对于成像光谱仪狭缝平行和垂直纸面两种特殊定标状况,推导出相应的光谱辐射信号电子数采集表达式,数值分析了在此两种定标状况下成像光谱仪光谱辐射定标的特性。结果表明,成像光谱仪狭缝取向对光谱辐射定标结果有明显不同的影响,对于狭缝平行纸面情况下,不同景物像元相同光谱通道采集到的信号电子数是不同的,越靠近辐照度标准灯,采集到的信号电子数越多,反之亦然;对于狭缝垂直纸面情况下,不同景物像元相同光谱通道采集到的信号电子数是相同的。 相似文献