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随着糖尿病的发病率逐年增高,为避免传统有创血糖监测血糖的痛苦,无创血糖监测已经越来越引起人们的重视。无创血糖检测技术就是在不对人体造成伤害的条件下检测人体血糖的方法。该方法可以避免传统试纸测试带来的痛苦,降低检测成本,提高病人测量的依从性,既能增加血糖检测的频率又能获得血糖的动态变化趋势,从而降低了患者糖尿病并发症的发生,同时可以避免针刺可能带来的感染,对于糖尿病人的自我监测具有非常重要的意义。详细介绍了当前各种无创血糖检测技术的原理,分析了各种技术的优缺点,并提供了国内外无创血糖仪的最新成果,还介绍了本人所在课题组所研发的基于代谢守恒原理的无创血糖监测产品。 相似文献
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应用蒙特卡罗方法模拟了三层皮肤组织中光的传输和分布情况,模拟结果得出光经过皮肤组织漫反射后的出射位置分布和出射角度分布情况;根据此模拟结果,分析和设计了一种具有特殊结构的血糖无创检测光纤探测器,此探测器在表皮和收集光纤之间设置了一组反射镜面,大部分光经镜面反射后被收集光纤收集。此设计弥补了光纤数值孔径对探测器收集效率的限制。 相似文献
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近红外光谱无创血糖测量的极限检测浓度研究 总被引:1,自引:0,他引:1
检测极限浓度综合了光子传输的微观过程信息、漫反射光的统计性质和仪器设备的系统性能,降低检测极限浓度是无创伤血糖浓度测量的目标所在。通过分析血糖浓度变化对光学参数的两种作用及其对光传播的影响,针对皮肤中葡萄糖主要分布真皮层的特点,引入有效信噪比的概念,推导了血糖检测极限浓度与光源检测器之间距离、有效仪器信噪比之间的关系。针对不同个体在表皮和真皮厚度的差异,用蒙特卡洛方法研究了其对检测极限浓度的影响,讨论了光学测头设计的方案和适应性。结果表明,通过选择合适的光源检测器之间距离,来自真皮层的有效信号能超过50%;假定仪器信噪比为10000,可获得满足FDA要求的血糖检测极限浓度。 相似文献
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结合太赫兹时域光谱系统,利用棱镜衰减全反射技术,设计了一种太赫兹衰减全反射光谱法的无创血糖检测系统。借助德拜模型分析了皮肤中含水量变化会影响皮肤在太赫兹波段的弛豫作用,得到皮肤复折射率与皮肤含水量的关系,利用菲涅耳公式给出了计算皮肤复折射率实部和虚部的方法。将太赫兹光谱法测得的人体大拇指皮肤复折射率的实部与虚部,与口服葡萄糖耐量试验实际测得的人体血糖浓度进行对比,得到了人体手指皮肤的太赫兹反射谱以及复折射率与人体血糖浓度成正相关的关系,为太赫兹应用于无创血糖浓度检测提供了参考。 相似文献
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基于逆向蒙特卡洛法的溶液葡萄糖浓度低相干测量 总被引:1,自引:0,他引:1
提出了基于蒙特卡洛逆运算的葡萄糖含量低相干干涉测量方法,理论研究了葡萄糖含量与光学参数的相关性.通过正向蒙特卡洛数值模拟说明了从干涉曲线中同时求解散射系数和吸收系数的条件和可行性.以脂肪乳悬混溶液Intralipid作为实验对象,研究了糖浓度变化对深度相关干涉信号的影响.利用低相干干涉测量系统配合逆向蒙特卡洛计算提取了散射和吸收系数,进而通过散射和吸收系数的变化量间接获得了溶液葡萄糖含量.对实验结果与双积分球测量结果进行了比较验证,并对存在的系统误差进行了修正.实验结果显示,在加入修正值后,测量的散射和吸收系数的最大相对误差分别为2.52%和3.11%.研究结果表明,葡萄糖含量与散射系数和干涉曲线存在高度相关性,在非前向散射条件下,可以同时测量吸收和散射系数.经过校准后的测量结果满足了实际要求. 相似文献
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基于传热正反模型的动态测温方法研究 总被引:2,自引:2,他引:0
为减少热惯性温度传感器的动态测温误差,提出了基于传热模型和反演算法的动态测温方法,其实质是将求解被测对象的真实温度转化为一个优化问题.该方法首先建立温度传感器非线性非定常瞬态传热正模型和有限元求解方程,并进行实验验证.在此基础上,推导了瞬态传热一阶敏度计算公式,建立了温度传感器的非稳态反演传热模型,结合快速反演算法,反求作为边界条件的被测对象真实温度.将所提出的动态测温方法应用于具有内外两层套管、传热过程复杂的复合温度传感器.实验和仿真结果均表明,正向模型的仿真值与测量值相比最大误差小于5℃,反演求解的被测对象真实温度误差不超过1%,热响应时间由548 s缩短到106s.应用实例分析结果表明,所提出的动态测温方法具有较高的准确性和快速性. 相似文献
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The cutting heat dissipation in chips, workpiece, tool and surroundings during the high-speed machining of carbon steel is
quantitatively investigated based on the calorimetric method. Water is used as the medium to absorb the cutting heat; a self-designed
container suitable for the high-speed lathe is used to collect the chips, and two other containers are adopted to absorb the
cutting heat dissipated in the workpiece and tool, respectively. The temperature variations of the water, chips, workpiece,
tool and surroundings during the closed high-speed machining are then measured. Thus, the cutting heat dissipated in each
component of the cutting system, total cutting heat and heat flux are calculated. Moreover, the power resulting from the main
cutting force is obtained according to the measured cutting force and predetermined cutting speed. The accuracy of cutting
heat measurement by the calorimetric method is finally evaluated by comparing the total cutting heat flux with the power resulting
from the main cutting force.
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Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(11): 1–4 [译自: 华南理工大学学报(自然科学版)] 相似文献
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为了评估光电容积脉搏波法在人体血液主要成分检测方面的精度水平,基于朗伯比尔定律及简化的光电容积脉搏波法测量模型,给出了物质成分测量的极限分辨浓度公式。对公式中的三个要素,即人体测量时的光强信噪比、光程、被测物质的摩尔消光系数进行了评估,获得了理论上光电脉搏波法对血红蛋白、白蛋白、血糖的极限分辨浓度。评估结果表明,光电容积脉搏波法可以测量的血红蛋白、白蛋白和血糖的极限分辨浓度水平分别约为100mg/dL,5000mg/dL以及10 000mg/dL。将该评价结果与现阶段临床需要的检测精度进行对比,可知光电容积脉搏波法能够满足需求,有望实现对血红蛋白的无创检测。 相似文献
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The cutting temperature and temperature distribution along the rake face of cutting tool and work piece is an essential factor in study of machining processes due to its effect on surface quality, tool life, tolerances, metallurgical behavior and chip-removing rate. Several methods have been introduced to measure temperature during machining, such as the thermocouple technique, infrared camera and metallurgical methods. Each of these methods has some advantages and limitations. In this article, an infrared high-speed sensor with specially designed software has been used to measure the transferred heat to the work piece during high speed machining (HSM) of bronze alloys. The results revealed that this system enhances accuracy and reduces the number of tests required. 相似文献
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《Measurement》2016
The temperature distribution information plays an important role in industrial applications. Owing to the advantages such as non-intrusive sensing and low cost, the ultrasonic tomography (UT) is considered to be a promising method for temperature field visualization. The ultrasonic time-of-flight (TOF) measurement and the reconstruction algorithm are crucial for practical applications of the UT measurement. In this paper, a dual-threshold measurement method is proposed to ensure a high-quality TOF measurement. In view of the inaccurate nature of the reconstruction model and TOF data, a new reconstruction method that integrates the advantages of the Tikhonov regularization method and the least squares support vector machine (LSSVM) is proposed to improve the reconstruction quality. The experimental results were compared against thermocouple measurements and the results show that the temperature distribution can be reconstructed with the error of 1.3%, which validates the feasibility and effectiveness of the proposed Tikhonov-LSSVM reconstruction algorithm. 相似文献