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Wireless contactless pressure measurement of an LC passive pressure sensor with a novel antenna for high-temperature applications 被引量:1
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作者 李晨 谭秋林 +3 位作者 薛晨阳 张文栋 李运芝 熊继军 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第4期540-545,共6页
In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature o... In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600℃. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor. 展开更多
关键词 ceramic antenna contactless pressure measurement high-temperature application wireless passive pressure sensor
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Frequency Measurement of Transient Oscillatory on LABVIEW
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作者 Haichao Guo 《Journal of Power and Energy Engineering》 2014年第4期673-679,共7页
Due to the sensitivity of the frequency measurement of power system transient oscillatory signal with respect to noise signal, a new measurement method based on Wavelet Transform and Windowed Fourier Transform is prop... Due to the sensitivity of the frequency measurement of power system transient oscillatory signal with respect to noise signal, a new measurement method based on Wavelet Transform and Windowed Fourier Transform is proposed. An analysis using LabVIEW on oscillatory signal containing various noise components is carried on and it is shown that the proposed method can detect the oscillatory frequency more accurately and quickly. 展开更多
关键词 transient OSCILLATORY FREQUENCY measurement WAVELET TRANSFORM Windowed FOURIER TRANSFORM
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Transient Stability Analysis Using Transmission Line Measurement
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作者 蔡国伟 程浩忠 +1 位作者 陈家荣 王承民 《Journal of Shanghai Jiaotong university(Science)》 EI 2004年第2期29-35,共7页
The novel quantitative assessment method using transmission line measurement was developed. A new style of stability criterion was suggested which is based on the line measurement. The stability indices for lines, cut... The novel quantitative assessment method using transmission line measurement was developed. A new style of stability criterion was suggested which is based on the line measurement. The stability indices for lines, cutsets and power system according to features of transient energy in the lines were given, which not only provide a reliable and accurate assessment of the transient stability of power system, but also can be used to assess the effect of lines and cutsets on the transient stability and identify the weak transmission segment. Examples were presented by simulation on the IEEE-39 buses test system. 展开更多
关键词 power system transient stability local network measurement stability criterion line stability index cutset stability index
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Heat transfer enhancement in MOSFET mounted on different FR4 substrates by thermal transient measurement
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作者 Norazlina M S Dheepan Chakravarthii M K +2 位作者 Shanmugan S Mutharasu D Shahrom Mahmud 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第9期549-556,共8页
Miniaturization of electronic package leads to high heat density and heat accumulation in electronics device, resulting in short life time and premature failure of the device. Junction temperature and thermal resistan... Miniaturization of electronic package leads to high heat density and heat accumulation in electronics device, resulting in short life time and premature failure of the device. Junction temperature and thermal resistance are the critical parameters that determine the thermal management and reliability in electronics cooling. Metal oxide field effect transistor(MOSFET)is an important semiconductor device for light emitting diode-integrated circuit(LED IC) driver application, and thermal management in MOSFET is a major challenge. In this study, investigations on thermal performance of MOSFET are performed for evaluating the junction temperature and thermal resistance. Suitable modifications in FR4 substrates are proposed by introducing thermal vias and copper layer coating to improve the thermal performance of MOSFET. Experiments are conducted using thermal transient tester(T3ster) at 2.0 A input current and ambient temperature varying from25℃ to 75℃. The thermal parameters are measured for three proposed designs: FR4 with circular thermal vias, FR4 with single strip of copper layer and embedded vias, and FR4 with I-shaped copper layer, and compared with that of plain FR4 substrate. From the experimental results, FR4I-shaped shows promising results by 33.71% reduction in junction temperature and 54.19% reduction in thermal resistance. For elevated temperature, the relative increases in junction temperature and thermal resistance are lower for FR4I-shaped than those for other substrates considered. The introduction of thermal vias and copper layer plays a significant role in thermal performance. 展开更多
关键词 metal oxide field effect transistor(MOSFET) thermal transient measurement heat transfer path FR4
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Single-Shot Measurement of Transient Phase Shift Induced by Laser Wake
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作者 董军 卢宗贵 +8 位作者 张波 彭志涛 孙志红 夏彦文 元浩宇 唐军 朱德燕 刘华 吕嘉坤 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第5期60-62,共3页
Based on the frequency-to-time mapping relation of the linearly chirped pulse, the temporal phase shift induced by a laser-excited wake in a helium gas jet is measured using a chirped-pulse spectral interferometry wi... Based on the frequency-to-time mapping relation of the linearly chirped pulse, the temporal phase shift induced by a laser-excited wake in a helium gas jet is measured using a chirped-pulse spectral interferometry with ~ 140 fs resolution over a temporal region of I ps in a single shot. In this measurement, the image of the wake is obtained with one-dimensional spatial resolution and temporal resolution limited only by the bandwidth and chirp of the pulse. The 'bubbles' feature of the wake structure, along with multiple wakes excited by the main lobe and the side lobe of a laser focal-spot, is captured simultaneously. 展开更多
关键词 Single-Shot measurement of transient Phase Shift Induced by Laser Wake
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VFT PHASE VOLTAGE MEASUREMENT IN THREE-PHASE ENCLOSED GIS 被引量:1
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作者 Zou Jianhua(邹建华) +3 位作者 Yue Ziding(岳子丁) Li Yang(李洋) 《Academic Journal of Xi'an Jiaotong University》 2002年第2期101-108,共8页
The measuring of VFT phase voltage in three-phase enclosed GIS is more complex and difficult than in single-phase ones. There are 3 capacitive sensors in the measuring system, the outputs of which are with a linear re... The measuring of VFT phase voltage in three-phase enclosed GIS is more complex and difficult than in single-phase ones. There are 3 capacitive sensors in the measuring system, the outputs of which are with a linear relation to the three phase voltages. This linear relation is presented with a factorial matrix. Because each capacitive sensor is coupled with the electric field of three phases (A, B, and C), the electric coupling coefficients are introduced. In order to determine the matrix of electric coupling coefficients, the numerical calculation method can be used. From the discussion on two types of three-phase enclosed GIS bus, i.e. standard arrangement and biased arrangement, the dominant electric coupling coefficients are named, which can be simply and approximately calculated by an analytic expression. Finally, as an example, the waveforms of VFT phase voltage generated on a three-phase enclosed GIS bus model are displayed. When a capacitive sensor is located at the ’shortest point’ of phase A (or B, or C), the VFT phase voltage V A (or V B, or V C) can almost be measured by that capacitive sensor alone. 展开更多
关键词 gas insulated substation(GIS) very fast transients(VFT) VOLTAGE measurement electric field ANALYTIC expression measurement apparatus VFT phase VOLTAGE wave
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High-precision nuclear magnetic resonance probe suitable for in situ studies of high-temperature metallic melts
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作者 Ao Li Wei Xu +4 位作者 Xiao Chen Bing-Nan Yao Jun-Tao Huo Jun-Qiang Wang Run-Wei Li 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第4期48-55,共8页
High-temperature nuclear magnetic resonance(NMR)has proven to be very useful for detecting the temperatureinduced structural evolution and dynamics in melts.However,the sensitivity and precision of high-temperature NM... High-temperature nuclear magnetic resonance(NMR)has proven to be very useful for detecting the temperatureinduced structural evolution and dynamics in melts.However,the sensitivity and precision of high-temperature NMR probes are limited.Here we report a sensitive and stable high-temperature NMR probe based on laser-heating,suitable for in situ studies of metallic melts,which can work stably at the temperature of up to 2000 K.In our design,a well-designed optical path and the use of a water-cooled copper radio-frequency(RF)coil significantly optimize the signal-to-noise ratio(S/NR)at high temperatures.Additionally,a precise temperature controlling system with an error of less than±1 K has been designed.After temperature calibration,the temperature measurement error is controlled within±2 K.As a performance testing,^(27)Al NMR spectra are measured in Zr-based metallic glass-forming liquid in situ.Results show that the S/NR reaches 45 within 90 s even when the sample's temperature is up to 1500 K and that the isothermal signal drift is better than0.001 ppm per hour.This high-temperature NMR probe can be used to clarify some highly debated issues about metallic liquids,such as glass transition and liquid-liquid transition. 展开更多
关键词 high-temperature NMR probe laser beams temperature measurement metallic melts
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Measurement of Deep Energy Level in InP: Fe by the Method of OTCS
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作者 SHAO Limei (Jilin Polytechnic University, Changchun 130022, CHN) YANG Wei YANG Ming YAN Ruhui (Technology Academy of Armor Force of P. L. A., Changchun 130117, CHN ) 《Semiconductor Photonics and Technology》 CAS 1998年第2期78-83,共6页
We have measured the deep energy level of the InP: Fe which is semi -insulator through the method of OTCS. The effect of light intensity on OTCS measurement is mainly discussed. There are electron trap of E_T =0.34 eV... We have measured the deep energy level of the InP: Fe which is semi -insulator through the method of OTCS. The effect of light intensity on OTCS measurement is mainly discussed. There are electron trap of E_T =0.34 eV and hole trap of E_T = 1.13 eV in InP: Fe under the strong light and low temperature. The location of the OTCS peak of electron trap (E_T = 0.34 eV) moves towards the direction of high temperaturer, when the light intensity was increased, E_T is different under different light intensity. It is corrected in terms of theory that the stuff ratio of the deep energy level is affected by the light intensity. The experiments show that the error is decreased greatly with the correction. 展开更多
关键词 Impurity Level measurement Optical transient Current Spectroscopy Semiconductor Materials
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Stability Monitoring and Control of Generation Based on the Synchronized Measurements in Nodes of Its Connection
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作者 Alexander Fishov Maria Shiller +1 位作者 Anton Dekhterev Vladimir Fishov 《Journal of Energy and Power Engineering》 2015年第1期59-67,共9页
Synchronized distributed measurements of mode parameters create a technical feasibility for development and implementing new technologies of control the mode stability and the admissibility of EPS (electric power sys... Synchronized distributed measurements of mode parameters create a technical feasibility for development and implementing new technologies of control the mode stability and the admissibility of EPS (electric power system) mode. Discussion will focus on different models obtained from data synchronized measurements for operational and automatic emergency control without EPS being totally controlled. According to the proposed technology, the generator's output power restrictions are determined in real-time by the terms a static stability using the generators' mode model as a multipole with connection nodes of generators' electromotive forces (the matrix of SMA (self and mutual admittances) of electromotive forces of generators). Potential applications of the technology are distribution network with the main substation and generators of commensurable capacity, and transmission network with large power plants (generators) distributed into the network. The one-level control system for all of generators with defining the generator's power limits relative to the main substation is implemented in the first case. In the second case, the two-level control system is brought in, based on the separation of large and small generation motion. The results of the method and technology efficiency verification are shown in the paper, by both computer simulations of the power system modes and its physical model. 展开更多
关键词 Power system static stability synchronized measurements normal mode transient mode post emergency mode matrix of self and mutual admittances.
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Performance of transient elastography in assessing liver fibrosis in patients with autoimmune hepatitis-primary biliary cholangitis overlap syndrome 被引量:16
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作者 Hui-Min Wu Li Sheng +8 位作者 Qi Wang Han Bao Qi Miao Xiao Xiao Can-Jie Guo Hai Li Xiong Ma De-Kai Qiu Jing Hua 《World Journal of Gastroenterology》 SCIE CAS 2018年第6期737-743,共7页
AIM To investigate the performance of transient elastography(TE) for diagnosis of fibrosis in patients with autoimmune hepatitis-primary biliary cholangitis(AIHPBC) overlap syndrome.METHODS A total of 70 patients with... AIM To investigate the performance of transient elastography(TE) for diagnosis of fibrosis in patients with autoimmune hepatitis-primary biliary cholangitis(AIHPBC) overlap syndrome.METHODS A total of 70 patients with biopsy-proven AIH-PBC overlap syndrome were included. Spearman correlation test was used to analyze the correlation of liver stiffness measurement(LSM) and fibrosis stage. Independent samples Student's t-test or one-way analysis of variance was used to compare quantitative variables. Receiver operating characteristics(ROC) curve was used to calculate the optimal cut-off values of LSM for predicting individual fibrosis stages. A comparison on the diagnostic accuracy for severe fibrosis was made between LSM and other serological scores.RESULTS Patients with AIH-PBC overlap syndrome had higher median LSM than healthy controls(11.3 ± 6.4 k Pa vs 4.3 ± 1.4 k Pa, P < 0.01). LSM was significantly correlated with fibrosis stage(r = 0.756, P < 0.01). LSM values increased gradually with an increased fibrosis stage. The areas under the ROC curves of LSM for stages F ≥ 2, F ≥ 3, and F4 were 0.837(95%CI: 0.729-0.914), 0.910(0.817-0.965), and 0.966(0.893-0.995), respectively. The optimal cut-off values of LSM for fibrosis stages F ≥ 2, F ≥ 3, and F4 were 6.55, 10.50, and 14.45 k Pa, respectively. LSM was significantly superior to fibrosis-4, glutaglumyl-transferase/platelet ratio, and aspartate aminotransferase-to-platelet ratio index scores in detecting severe fibrosis(F ≥ 3)(0.910 vs 0.715, P < 0.01; 0.910 vs 0.649, P < 0.01; 0.910 vs 0.616, P < 0.01, respectively).CONCLUSION TE can accurately detect hepatic fibrosis as a noninvasive method in patients with AIH-PBC overlap syndrome. 展开更多
关键词 LIVER stiffness measurement transient elastography LIVER fibrosis AUTOIMMUNE hepatitis PRIMARY BILIARY CHOLANGITIS Overlap syndrome
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Transient elastography for the assessment of chronic liver disease: Ready for the clinic? 被引量:11
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作者 JFL Cobbold S Morin SD Taylor-Robinson 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第36期4791-4797,共7页
Transient elastography is a recently developed non- invasive technique for the assessment of hepatic fi brosis. The technique has been subject to rigorous evaluation in a number of studies in patients with chronic liv... Transient elastography is a recently developed non- invasive technique for the assessment of hepatic fi brosis. The technique has been subject to rigorous evaluation in a number of studies in patients with chronic liver disease of varying aetiology. Transient elastography has been compared with histological assessment of percutaneous liver biopsy, with high sensitivity and specificity for the diagnosis of cirrhosis, and has also been used to assess pre-cirrhotic disease. However, the cut-off values between different histological stages vary substantially in different studies, patient groups and aetiology of liver disease. More recent studies have examined the possible place of transient elastography in clinical practice, including risk stratifi cation for the development of complications of cirrhosis. This review describes the technique of transient elastography and discusses the interpretation of recent studies, emphasizing its applicability in the clinical setting. 展开更多
关键词 FIBROSCAN transient elastography Liver stiffness measurement Hepatic fibrosis HEPATITIS
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Transient elastography in chronic hepatitis B: An Asian perspective 被引量:3
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作者 Seung Up Kim Kwang-Hyub Han Sang Hoon Ahn 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第41期5173-5180,共8页
Transient elastography (TE) is a new non-invasive tool for assessing liver stiffness, which is correlated with the histologic stage of liver fibrosis. Many studies have reported a good accuracy of TE in predicting sig... Transient elastography (TE) is a new non-invasive tool for assessing liver stiffness, which is correlated with the histologic stage of liver fibrosis. Many studies have reported a good accuracy of TE in predicting signif icant fibrosis and an optimal accuracy in predicting cirrhosis. Furthermore, the potential role of TE in screening the general population has also been proven. TE thus helps physicians to decide treatment strategies, predict prog-nosis, and monitor disease progression in patients with chronic liver disease and to screen the general popula-tion to identify high risk patients with potential liver disease. However, most data on the clinical roles of TE have been gathered in European patients with chronic hepatitis C (CHC), because TE was first developed in France. Accordingly, much data on the usefulness of TE in patients with CHC has accumulated. Recently, however, vigorous efforts have been made to apply TEto patients with chronic hepatitis B (CHB), and TE has also proved to have acceptable accuracy in diagnosing liver fibrosis and cirrhosis in these patients. Thus, we focused on TE in the Asian population with CHB in comparison with the European population with CHC and found that the diagnostic performance and cutoff values were different between the 2 populations possibly as a result of several different confounders between Asian and European populations (the etiology of chronic liver disease, histologic features, major fluctuation in alanine aminotransferase levels, and the prevalence of high body mass index and metabolic syndrome). Therefore, further studies tailored to the Asian population with CHB should be performed before the widespread application of TE in Asian populations with CHB. 展开更多
关键词 ASIA Chronic hepatitis B FIBROSCAN Hepatitis B virus Liver stiffness measurement transient elas-tography
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Shear wave elastography may be sensitive and more precise than transient elastography in predicting significant fibrosis 被引量:1
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作者 Tian-Tian Yao Jing Pan +3 位作者 Jian-Dan Qian Hao Cheng Yan Wang Gui-Qiang Wang 《World Journal of Clinical Cases》 SCIE 2020年第17期3730-3742,共13页
BACKGROUND Noninvasive measurements including transient elastography(TE)and twodimensional shear wave elastography(SWE)have been used clinically instead of liver biopsy for regular assessment of liver fibrosis in chro... BACKGROUND Noninvasive measurements including transient elastography(TE)and twodimensional shear wave elastography(SWE)have been used clinically instead of liver biopsy for regular assessment of liver fibrosis in chronic hepatitis B(CHB)patients.AIM To investigate the diagnostic efficiency of SWE compared to TE by assessing independent influencing factors and performance for diagnosing significant fibrosis based on our cohort of treatment-naive CHB patients.METHODS Fifty-four treatment-naive CHB patients who underwent liver biopsy to determine whether to initiate antiviral therapy were enrolled.SWE,TE,serum tests and liver biopsy were performed for all participants.The fibrosis-4 and aspartate aminotransferase to platelet ratio index scores were also calculated.Potential independent influencing factors on SWE and TE values were analyzed.Based on liver pathology results,the agreement and correlation were determined,and a comparison of the two methods was performed.RESULTS There were 27 cases(50%)of mild fibrosis(F0-F2)and 27(50%)cases of significant fibrosis(F3-F6);fibrosis was assessed with the Ishak scoring system.Multivariate linear regression analyses revealed that the fibrosis stage was the only factor that affected the SWE values(P<0.001),whereas the total bilirubin level(P=0.013)and fibrosis stage(P=0.037)were independent factors that affected TE values.Orthogonal partial least squares discriminant analysis showed that the number of independent factors(VIP>1)was higher for TE than SWE.Bland-Altman analysis showed satisfactory agreement between liver stiffness measurements(LSMs)of SWE and TE.Both SWE and TE could significantly discriminate significant fibrosis from mild fibrosis(P<0.001).SWE exhibited a higher correlation with LSMs of liver fibrosis than TE(r=0.65 and 0.50,P<0.001).The diagnostic performance of SWE was better than that of TE for significant fibrosis(F>2).The areas under the receiver operating characteristic curves of SWE and TE were 0.786 and 0.714,respectively.The optimal LSM cutoff values of SWE and TE were 9.05 kPa and 8.15 kPa,respectively.CONCLUSION Compared to the TE value,the SWE value was less affected by other factors.SWE may be more sensitive and precise than TE in predicting significant fibrosis(>F2)in CHB patients. 展开更多
关键词 Liver stiffness measurements Liver fibrosis Shear wave elastography transient elastography Chronic hepatitis B Diagnostic efficiency
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时间分辨动态LIBS测量方法
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作者 张振荣 方波浪 +2 位作者 李国华 叶景峰 王晟 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第4期952-955,共4页
针对激光诱导击穿光谱(LIBS)研究对时间分辨动态光谱测量方法的需求,建立了基于多通道光纤束的动态LIBS测量方法。该方法首先利用不同长度的光纤组成多通道光纤束,对瞬态LIBS信号进行差异延迟,使按照特定时间序列发射的光谱信号同步到... 针对激光诱导击穿光谱(LIBS)研究对时间分辨动态光谱测量方法的需求,建立了基于多通道光纤束的动态LIBS测量方法。该方法首先利用不同长度的光纤组成多通道光纤束,对瞬态LIBS信号进行差异延迟,使按照特定时间序列发射的光谱信号同步到达探测器,而后采用面阵ICCD相机对同步到达的多通道光谱信号进行高时间分辨探测。该方法单次测量即可获得LIBS辐射不同时刻的时间分辨光谱。为了验证基于多通道光纤束的动态LIBS测量方法,研制了具有19个通道的光纤束,光纤束中包含的各个单根光纤长度呈等差数列排布,长度差设置为10 m,对应测量的时间间隔约为50 ns,单次测量记录的总时间长度近900 ns。分别基于短脉冲激光光源和标准光源,开展了系统时间响应和光谱响应特性研究,获得了系统的时间响应数据和光谱响应曲线。用YAG激光器的二倍频激光(532 nm)诱导Si产生等离子体辐射光谱,在线测量了辐射光谱的时间演化历程,获得了Si等离子体辐射过程中SiⅠ390.52 nm,SiⅡ385.51 nm,SiⅡ413.12 nm谱线从0~898 ns时间范围内19个时刻的光谱信息,获得了特征光谱的演化规律,验证了该测量方法的可行性。结果表明,利用该测量方法,单次测量可以获得瞬态LIBS辐射过程中19个时刻的光谱参数,具有很高的测量效率。对于实验成本较高、运行频率低的激光诱导等离子体实验研究,采用该方法可以大大降低了测量成本,有效提升等离子体时间分辨动态光谱测量能力。 展开更多
关键词 激光诱导击穿光谱 时间分辨 瞬态辐射 多通道测量 光纤束
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高温蒸汽凝结法相对湿度测量
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作者 高琳锋 徐志军 +3 位作者 梁俊钦 张彩良 皇甫永春 陈建利 《国外电子测量技术》 2024年第7期140-147,共8页
为实现露点温度100℃以上高温压力蒸汽相对湿度的精确测量,设计了以凝结称重装置、不凝气体含湿量测量装置、数据处理系统为核心部件的凝结法相对湿度测量系统。测量系统依据蒸汽相对湿度与含湿量对应关系,采用蒸汽快速凝结,实时监测冷... 为实现露点温度100℃以上高温压力蒸汽相对湿度的精确测量,设计了以凝结称重装置、不凝气体含湿量测量装置、数据处理系统为核心部件的凝结法相对湿度测量系统。测量系统依据蒸汽相对湿度与含湿量对应关系,采用蒸汽快速凝结,实时监测冷凝液质量与不凝气流含湿量的方式实现了目标蒸汽所处温度、压力条件下相对湿度的在线测量。凝结法测量工艺能实现露点温度-40℃~130℃条件下气体相对湿度0.15%~100%范围内的有效测量。在露点温度128℃、相对湿度95%条件下,测量不确定度0.59%,测量偏差小于0.4%,具有测量精度高、测量速率快的特点。该系统能开展瞬态条件下蒸汽相对湿度测量,湿度测量值能溯源到国际单位制基本单位。 展开更多
关键词 蒸汽凝结 湿度测量 瞬态条件 计量溯源
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基于拉普拉斯变换的瞬态热流测量方法
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作者 黄由之 全永凯 +2 位作者 徐国强 柴杰明 殷秋洋 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2024年第12期3834-3841,共8页
针对航空发动机热端部件表面瞬态热流测量的问题,面向一种当前较为先进的横向测温差薄膜热流计结构,针对其瞬态测量的导热模型,在稳态测量原理方程中加入时间项,建立瞬态导热微分方程组,采用拉普拉斯变换方法并结合解卷积方法对导热方... 针对航空发动机热端部件表面瞬态热流测量的问题,面向一种当前较为先进的横向测温差薄膜热流计结构,针对其瞬态测量的导热模型,在稳态测量原理方程中加入时间项,建立瞬态导热微分方程组,采用拉普拉斯变换方法并结合解卷积方法对导热方程进行求解,提出该型薄膜热流计瞬态条件下的表面热流测量方法;采用数值模拟手段,对所提方法进行验证。结果表明:所提方法突破了原始的稳态测量局限,可用于固体表面瞬态热流测量,计算得到的热流计表面热流与真实值符合较好;在表面阶跃热流条件下,测量精度约为8.2%;在100 Hz正弦热流条件下,测量精度约为4.0%。 展开更多
关键词 航空发动机 热流测量 薄膜热流计 瞬态方法 数值模拟
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针对电力系统数据缺失的暂态电压稳定评估方法 被引量:2
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作者 姜鸣瞻 杨楚原 +4 位作者 蒋何为 崔梓琪 袁铭洋 刘颂凯 张磊 《内蒙古电力技术》 2024年第1期27-32,共6页
针对数据缺失时暂态电压稳定评估模型精度下降的问题,提出一种基于多视图缺失数据填充和门控图神经网络的电力系统暂态电压稳定评估方法。首先,基于多视图互补的时空视图来填充缺失数据,得到完整的数据集;然后,采用修复完整的数据集训... 针对数据缺失时暂态电压稳定评估模型精度下降的问题,提出一种基于多视图缺失数据填充和门控图神经网络的电力系统暂态电压稳定评估方法。首先,基于多视图互补的时空视图来填充缺失数据,得到完整的数据集;然后,采用修复完整的数据集训练门控图神经网络模型进行暂态电压稳定评估,评估模型要进行快速更新,以提高在线应用的性能;最后,在IEEE39节点系统算例上进行验证所提方法的有效性。仿真结果表明,本文方法可以在任何同步向量测量单元放置信息丢失和网络拓扑变化的情况下及时有效地填补缺失数据,且所用评估模型的评估性能具有显著优势。 展开更多
关键词 测量数据缺失 时空视图 门控图神经网络 暂态电压稳定评估
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双膜量子点表面热流密度场测量技术
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作者 王一笑 张丹 +2 位作者 涂茂萍 周文博 赵冰超 《化工进展》 EI CAS CSCD 北大核心 2024年第2期872-881,共10页
现有热流密度场测量技术主要局限在分辨率低、瞬态响应慢、成本高等方面。为解决这一问题,本文提出了一种测量热流密度场的新技术。量子点是一种纳米级的光致发光半导体材料,其光致荧光光谱强度随温度的变化呈现线性变化趋势。基于该效... 现有热流密度场测量技术主要局限在分辨率低、瞬态响应慢、成本高等方面。为解决这一问题,本文提出了一种测量热流密度场的新技术。量子点是一种纳米级的光致发光半导体材料,其光致荧光光谱强度随温度的变化呈现线性变化趋势。基于该效应,设计并制作了双膜量子点试片,搭建了量子点热流密度场测量实验系统,开展了标定与测量实验。结果表明:在本研究实验范围内,量子点膜的平均光致荧光强度随温度的升高呈现线性下降趋势;测得在本研究实验条件下10s内纯水液滴受热蒸发过程中底层平均热流密度约为3.4×10^(4)W/m^(2),测量不确定度为0.14;本研究测量方法的空间分辨率可达30μm级,响应时间为秒级,实现了对表面热流密度场的高分辨率、低延迟测量。基于分辨率高、延迟低的优势,本研究可以有效应用于旋转叶片、高速飞行器、微纳米元件等传统测量方法难以开展的测试环境。 展开更多
关键词 量子点 纳米材料 热流密度 测量 不确定度 分辨率 瞬态响应
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高功率激光装置中瞬态磁场信号的研究
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作者 朱宇洁 郭晓东 +1 位作者 何鹏 于明媚 《太赫兹科学与电子信息学报》 2024年第4期412-418,430,共8页
现有高功率激光装置中瞬态磁场测量装置未考虑屏蔽性能和信号还原。为了准确地对打靶后产生的瞬态磁场进行分析,根据瞬态磁场的频率范围和特点,基于电磁感应原理,采用黄铜作为屏蔽材料,利用皮革作为绝缘材料,设计并研制了一款适用于高... 现有高功率激光装置中瞬态磁场测量装置未考虑屏蔽性能和信号还原。为了准确地对打靶后产生的瞬态磁场进行分析,根据瞬态磁场的频率范围和特点,基于电磁感应原理,采用黄铜作为屏蔽材料,利用皮革作为绝缘材料,设计并研制了一款适用于高功率激光装置中瞬态磁场测量的传感器。频率响应达到500 MHz,完成了相应瞬态磁场的测量,为高功率激光装置的电磁干扰、电磁兼容方面研究提供了测试手段和数据支撑。 展开更多
关键词 瞬态磁场 瞬态磁场传感器设计 瞬态磁场测量
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基于生成对抗网络的半航空瞬变电磁噪声数据扩充方法
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作者 冯威 冯浩 +6 位作者 肖立江 陈品明 刘东 王用鑫 周小生 孙怀凤 王震 《物探与化探》 CAS 2024年第3期812-819,共8页
半航空瞬变电磁噪声数据形式复杂,获取成本高、数据量稀缺,难以通过传统的扩充方法进行数据扩充,极大地影响了后续降噪工作的开展。针对这个问题,本研究提出了基于生成对抗网络的半航空瞬变电磁信号数据扩充方法,通过将生成器设计为LST... 半航空瞬变电磁噪声数据形式复杂,获取成本高、数据量稀缺,难以通过传统的扩充方法进行数据扩充,极大地影响了后续降噪工作的开展。针对这个问题,本研究提出了基于生成对抗网络的半航空瞬变电磁信号数据扩充方法,通过将生成器设计为LSTM网络,基于实采噪声数据集,进行生成器与判别器模型的训练,成功获取了可以生成仿真噪声数据的生成器模型,之后分析了生成器生成的仿真噪声与实采噪声的分布,并且对比了扩充前后降噪网络的表现,验证了本方法对于半航空瞬变电磁实采噪声数据的扩充是真实有效的。 展开更多
关键词 半航空瞬变电磁 生成对抗网络 实采噪声 数据扩充
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