In order to improve the measurement accuracy of graphene oxide humidity sensor, a high sensitivity and high linearity graphene oxide humidity sensor was studied. The output characteristics of the sensor under different interdigital electrode channel widths and different graphene oxide concentrations were analyzed. The results show that when the concentration of GO is 2.0 mg/ml and the width of electrode channel is 50 μm, higher static sensitivity and better dynamic response can be obtained, and the linearity of the sensor can be significantly improved by adding a partial voltage conversion circuit.

The aviation oxygen system is an important guarantee to complete the flight mission. It is necessary to monitor the oxygen source pressure index of the oxygen cylinder in real time. Using piezoresistive element, adopting voltage stabilizing module circuit, signal amplification and conditioning circuit, using Pt100 to assist in temperature measurement, collecting pressure and temperature sensor signal conditioning circuit to output voltage signal for analog-to-digital conversion, using AD0809 to carry out two-way data collection, data processing based on single chip STC89C51, combining ideal gas state equation with van der Waals state equation to correct pressure calculation, get more accurate pressure value, and display the gas content through LCD1602.

Flexible pressure sensors have advantages in human walking feature recognition because of their good flexibility and sensitivity. In this article, a flexible pressure sensor with stable mechanical properties and high sensitivity was designed based on the single-layer interdigital electrode made by the screen-printing process and the piezoresistive layer with a pyramidal microstructure made by the double inversion method. This structural design improves the sensitivity and wear resistance of the flexible pressure sensor and reduces the difficulty of packaging. The prepared flexible pressure sensor shows a higher sensitivity (−0.886 kPa $^{-{1}}$ ), a wider measurement range (0–180 kPa), a faster response time (80 ms), a lower detection pressure (11.8 Pa), and excellent durability. Then, a human plantar pressure monitoring system based on the flexible pressure sensor array was constructed to reflect the changes in human plantar pressure. Also, this monitoring system can recognize five types of human walking features through the support vector machine (SVM) algorithm. This work proves that the prepared flexible pressure sensor can be used as a flexible wearable device to accomplish complex tasks, such as recognizing human walking features, and it shows great potential in the field of health diagnosis.

DC high voltage dividers are widely used as standard devices for proportional measurement of high DC voltages by attenuating them to smaller DC voltages suitable for direct measurement using electrical instruments. To address the calibration challenge of high voltage level dividers where high voltage level dividers cannot be directly calibrated using the comparison method, a distributed synchronous measurement device for direct current voltage was designed and implemented on the low voltage arm of the direct current high voltage divider. A novel traceability method for the ratio calibration of direct current high voltage dividers was proposed. Two serially connectable 100 kV direct current high voltage dividers were employed to validate the effectiveness of the proposed traceability method at 200 kV using the aforementioned device and method. Experimental results demonstrate that the relative difference between the traceability method and the direct comparison method is less than 0.005%.

北京信息科技大学传感技术课程经过多年的改革探索与实践,形成了一套线上线下混合式教学模式—以慕课为基础构建翻转课堂;"以学生为中心"贯彻OBE理念;引入课程思政实现立德树人;注重传感技术在工程实际中的应用;打造具有"高阶性、创新性和挑战度"的实践环节;加强过程性考核;教学目标力求将知识目标、能力目标和素质目标相结合,满足新工科背景下工程教育专业认证的要求.实践表明,传感技术教学方法的改革有效激发了学生的学习兴趣,提高了在实践中的创新意识和科学思维,培养了解决复杂工程实际问题的综合能力.

The article aims to realize the remote measurement calibration of the high voltage DC voltage divider. The traditional calibration method is to send the instrument to the higher-level verification organization or the verification personnel to the site for verification, which is time-consuming and has the risk of damage during transportation, while remote calibration can perfectly solve these problems. Based on QT, we developed the console and fieldside software, realized the communication between the software of both sides and the cloud platform through sockets, and then used the cloud platform to forward messages to realize the communication between the two sides. The Ezviz Cloud is applied to realize real-time monitoring of on-site images and voice calls to ensure the legality of calibration. The verification results show that the cloud-based remote calibration system of the high-voltage DC voltage divider can achieve the purpose of remote calibration.

本文的主要目的是实现光电式的无创酒精浓度检测,与目前已经普及的呼气式酒精浓度检测仪相比,由于不需要不断的更换吹气管,从而会更加的卫生和低成本.而就产品本身而言,会更加的轻巧.所以,本产品对血液中的酒精浓度进行无创检测有着十分重要的意义.研究使用近红外光源测量人体血液中酒精浓度变化的原理及方法.使用光电容积脉搏波描记法采集血液数据,使用Matlab通过大量数据拟合出一条曲线,并且得到了该曲线的计算方程,除此之外,本文还创新性的使用了近红外长波波段的光源.

针对直流逆变电阻焊机焊接电流精确测量的需求,提出基于光纤电流传感技术的焊接电流测量方法.建立了光纤电流传感器闭环检测系统动态模型,通过优化系统的前向增益,提升了传感器响应速度和带宽.仿真和实验结果表明:传感器的上升时间约为4.1 μs,在DC～30 kHz范围内幅频特性衰减小于0.3％.基于该动态模型计算传感器对焊接电流纹波分量的响应,仿真结果表明:系统的动态跟踪能力可满足对纹波电流的测量需求.利用等安匝法对光纤电流传感器进行校准,在直流5～50 kA范围内,传感器的测量误差优于±0.05％.现场实验结果证明了光纤电流传感器用于直流逆变焊接电流测量及电焊电流测试仪现场校准的可行性.

Borehole measuring instruments are widely used in coal mine gas drainage and directional drilling. In recent years， in the process of wind drilling for soft coal seams, the inclinometer is affected by the friction between the wind motor and the drill pipe, and the temperature of the inclinometer is higher, which reduces the measurement accuracy of the inclinometer. In this paper, the temperature drift correction work is done for the magnetoresistive sensor and the gravity acceleration sensor in the measurement part of the inclinometer, so that the system can still meet the accuracy requirements when working at high temperatures. According to the simulation, the measurement results at high temperature are consistent with the measurement accuracy at room temperature, which meets the accuracy requirements of inclinometer products.

传感器课程经过多年改革探索与实践,基于"重视基础、体现现代、趋向前沿、交叉综合"的课程建设原则,提出"三闭环三收放"的教学思维模式——教学内容闭环,理论实践闭环,教学过程闭环;教学内容收放,教学方法收放,实验设计收放.实践表明:基于MOOC的三闭环三收放混合式教学设计,使学生体验了"踮脚才够得着"的学习挑战,增强了学生经过刻苦学习收获能力和素质提高的成就感,进行科研探究的意愿明显增强.该课程教学方法可直接应用于大学生电子设计竞赛、机器人比赛、国际互联网+创新创业大赛等,教书育人效果显著.

Nitrate contamination is a common problem in groundwater around the world. Nitrate can be cathodically reduced in bioelectrochemical systems using autotrophic denitrifiers with low energy investment and without chemical addition. Successful denitrification was demonstrated in previous studies in both microbial fuel cells and microbial electrolysis cells (MECs) with continuous current flow, whereas the impact of intermittent current supply (e.g., in a fluidized-bed system) on denitrification and particularly the electron-storing capacity of the denitrifying electroactive biofilms (EABs) on the cathodes have not been studied in depth. In this study, two continuously fed MECs were operated in parallel under continuous and periodic polarization modes over 280 days, respectively. Under continuous polarization, the maximum denitrification rate reached 233 g NO3--N/m3/d with 98% nitrate removal (0.6 mg NO3--N/L in the effluent) with negligible intermediate production, while under a 30 s open-circuit/30 s polarization mode, 86% of nitrate was removed at a maximum rate of 205 g NO3--N/m3/d (4.5 mg NO3--N/L in the effluent) with higher N2O production (6.6-9.3 mg N/L in the effluent). Conversely, periodic polarization could be an interesting approach in other bioelectrochemical processes if the generation of chemical intermediates (partially reduced or oxidized) should be favored. Similar microbial communities dominated byGallionellaceaewere found in both MECs; however, swapping the polarization modes and the electrochemical analyses suggested that the periodically polarized EABs probably developed a higher ability for electron storage and transfer, which supported the direct electron transfer pathway in discontinuous operation or fluidized biocathodes.

研究使用近红外光源测量人体血糖变化的原理及方法.使用光电容积脉搏波描记法采集血液数据,通过朗伯-比尔定律计算血糖浓度与血液吸光度的关系.基于最小二乘法建立模型,并设计了一种初步的验证装置.实验结果表明,检测系统的测试集相关系数为0.976,均方根误差为0.357,相对误差为±15％,满足临床应用要求.

Noninvasive detection of blood components is the most ideal and effective method to prevent and detect many clinical diseases. However, the accuracy of noninvasive detection based on the spectrum is not always satisfactory. The influence of various interferences in measurement limits the accuracy of the analysis. The dynamic spectrum theory can theoretically eliminate the individual differences and measurement environment influence and improve measurement accuracy. The concentration of globulin is closely related to the status of the immune system, which is of great significance for clinical diagnosis. This paper improves the signal-to-noise ratio from all links of dynamic spectrum data processing to realize the noninvasive detection of globulin. Through reasonable pretreatment, extraction, quality evaluation, and variable screening, the valid information of the spectrum gets maximum utilization. Finally, using the partial least squares prediction model to predict globulin concentration. The results show that the model established by dynamic spectrum treated by this method has a good predictive performance for globulin. The correlation coefficient of the prediction set is 0.962, the root-mean-square error of the prediction set is only 1.058 g/L, the correlation coefficient of the calibration set is 0.996, and the root-mean-square error of the calibration set is 0.332 g/L. The experimental results show that reasonable data processing of dynamic spectrum can effectively improve the signal-to-noise ratio of the data, make the established model have good prediction accuracy and performance, and realize the high-precision prediction globulin. This paper provides a complete research idea and method for the noninvasive detection of blood components. It is hopeful to realize the noninvasive quantitative detection of trace components in blood.

随着新工科建设、工程教育专业认证的推进,传感技术课程经过多年改革探索与实践,形成了一套线上线下混合式的教学模式.尤其是对于实践课,积极引导学生进行探究式和个性化学习,鼓励学生开展自主创新性和科研探究性实验,在线上师生讨论的基础上,线下利用讨论课协助学生确定实验方案,并指导学生在实验室完成整个传感器检测系统的设计与调试.实践表明:基于OBE理念,以学生为中心,促进其积极参与自主学习与实践,能有效激发学生的学习兴趣,提高其在实践中的创新意识和科学思维方法,培养其解决较复杂工程实际问题的综合能力.

目前,血糖测量通常采用人体静脉取血进行生化分析,或指端取血通过血糖仪进行测量,两种方法均为有创测量方法,既易产生血液交叉感染又为病人带来痛苦.所以本文设计了基于ARM的近红外光谱无创血糖检测系统,是基于ARM 的近红外光谱无创血糖测量硬件设计.主要功能包括,通过指夹式光电探测器采集信号,然后进过信号,放大电路和滤波电路,输送进 ARM 进行处理,存储和显示.研究内容是通过人体血液中葡萄糖对 700nm 到 800nm 的近红外光的吸收性,得到电信号,经过硬件电路对信号的处理和采集和软件的建模,算出血糖浓度.

Taking the blood glucose concentration as an example, the accuracy of the blood glucose measurement system is improved by means of the simultaneous incorportation of the extraction data form dynamic spectra and the influencing factors of non-measured components into the prediction model. The blood glucose prediction model is established through the support vector machine algorithm. The modeling results show that the prediction value from the multi-factor-considered model is superior to that from the non-measurement-component-considered model. The correlation coefficient of the former is 0.9627, higher by 14.23% , the root mean square error is 0.13, reduced by 43.12%, and the number of samples with a relative error in the range of 10% is higher by 8.33%, compared with those of the latter.

血糖浓度的无创测量在临床上有着重要的意义.通过光学方法可以达到对血液成分进行无创检测的目的,目前大多数研究都采用近红外光谱进行预测,在血液成分无创检测的研究中取得了较好的效果.由于血液中成分对于不同波段有着不同的性质,为提高测量精度,采集多模式的光谱数据进行建模预测,对于同一样本分别采集紫外透射光谱、紫外荧光光谱和近红外透射光谱.试验共采集了91份血浆样本,同时获取血液中血糖浓度的实际生化分析结果.采用支持向量机方法,对三组光谱信息和血糖浓度真值进行建模.得到模型的训练集相关系数97.29％,均方根误差0.355 8 mmol/L,测试集相关系数为96.3％,均方根误差为0.380 4 mmol/L,最大相对误差为13.68％,平均相对误差为0.069％.结果 表明,通过多模式的光谱信息进行血糖浓度的预测可得到较高的精度.

基于电能计量芯片,研制一种车载列车能耗采集装置.配合轨道交通列车适用的电压、电流传感器,实现了分类计算并累积列车的牵引能耗数据、再生电能数据及总电能,并在实验室进行了校准.校准结果显示,该套列车能耗计量装置的测量准确度优于2％.

校准工厂的传感器时,针对其不易直接连接电脑端采集数据的特点,设计一套非接触式的数据采集装置.设计采用摄像头采集数据图像,电脑端实时处理的数字识别系统.数字识别部分分为图像预处理,字符分割、字符识别三部分.采用中值滤波的方法消除环境杂质光的影响,采用连通域的方法分割字符,字符识别算法是其核心技术,采用穿线法识别数字.在实验室进行测试,实验结果表明,数字识别率达到99％,识别时间为40ms,具有识别率高,耗时短的优点.

在工程教育认证背景下,将OBE教学模式引入传感技术实验教学中,以培养解决复杂工程问题和创新能力为目标,在以学生为中心优化设计实验内容、以学生学习效果为导向改革实验教学方法和实验考核方式等方面做了一些尝试,从而提高了学生自我学习的能力、创新意识和工程实践能力,并获得了进一步持续教学改进的经验.