期刊文献+
共找到4,727篇文章
< 1 2 237 >
每页显示 20 50 100
TD-DFT Study on the Electronic Spectrum Properties of 2,7′-(Ethylene)-bis-8-hydroxyquinoline and Its Derivatives 被引量:1
1
作者 李志锋 朱元成 +1 位作者 袁焜 康敬万 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2008年第1期63-69,共7页
The structures of 2,7'-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet... The structures of 2,7'-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7'-(ethylene)-bis-8-hydroxyqulnoline and its derivatives were optimized by CIS/6-31G(d). The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory (TD-DFT) by the B3LYP method with the 6-31G(d) basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline. 展开更多
关键词 8-hydroxyquinolinolinato derivative electron spectrum excited state TD-DFT
下载PDF
Electronic structure and infrared spectrum of a W_n C^(0,±) (n = 1-6) cluster 被引量:1
2
作者 张秀荣 康张李 郭文录 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第10期204-211,共8页
WnC0'± (n= 1-6) clusters are investigated by using the density functional theory (DFT) at the B3LYP/LANL2DZ level. We find that the neutral, anionic and cationic ground state structures are similar within th... WnC0'± (n= 1-6) clusters are investigated by using the density functional theory (DFT) at the B3LYP/LANL2DZ level. We find that the neutral, anionic and cationic ground state structures are similar within the same size, and constituted by substituting a C atom for one W atom in the structures of Wn+1 clusters. The natural bond orbital (NBO) charge analyses indicate that the direction of electron transfer is from the W atom to the 2p orbital of the C atom. In addition, the calculated infrared spectra of the WnC0'± (n= 2-6) clusters manifest that the vibrational frequencies of neutral, anionic and cationic clusters are similar in a range of 80 cm-1-864 cm-1. The high frequency, strong peak modes are found to be an almost stretched deformation of the carbide atom. Finally, the polarizabilities of WnC0'± (n= 1-6) clusters are also discussed. 展开更多
关键词 WnC0'± (n= 1-6) clusters electronic structure infrared spectrum density functionaltheory
下载PDF
Identification of the unknown shielding parameters with gammaray spectrum using a derivative-free inverse radiation transport model 被引量:3
3
作者 Ying Chen Lian-Ping Zhang +4 位作者 Sa Xiao Lun-Qiang Wu Shan-Li Yang Bing-Yuan Xia Jian-Min Hu 《Nuclear Science and Techniques》 SCIE CAS CSCD 2018年第5期75-81,共7页
Identifying the unknown geometric and material information of a multi-shield object by analyzing the radiation signature measurements is always an important problem in national and global security. In order to identif... Identifying the unknown geometric and material information of a multi-shield object by analyzing the radiation signature measurements is always an important problem in national and global security. In order to identify the unknown shielding layer thicknesses of a source/shield system with gamma-ray spectra, we have developed a derivative-free inverse radiation transport model based on a differential evolution algorithm with global and local neighbourhoods(IRT-DEGL). In the present paper, the IRT-DEGL model is further extended for estimating the unknown thicknesses with random initial guesses and material mass densities of multi-shielding layers as well as their combinations. Using the detected gamma-ray spectra,the illustration of inverse studies is implemented and the main influence factors for inverse results are also analyzed. 展开更多
关键词 INVERSE problem derivative-FREE INVERSE RADIATION transport model GAMMA-RAY spectrum Multishielding layers
下载PDF
MODIFICATION OF ABSORPTION SPECTRUM OF GaAs/AlGaAs QUANTUM WELL INFRARED PHOTODETECTOR BY POSTGROWTH ADJUSTMENT 被引量:2
4
作者 Y FU YANG Chang-Li 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2006年第1期1-5,共5页
Quantum well intermixing techniques modify the geometric shape of quantum wells to allow postgrowth adjustments.The tuning effect on the optical response property of a GaAs/AlGaAs quantum well infrared photodetector(Q... Quantum well intermixing techniques modify the geometric shape of quantum wells to allow postgrowth adjustments.The tuning effect on the optical response property of a GaAs/AlGaAs quantum well infrared photodetector(QWIP) induced by the interdifussion of Al atoms was studied theoretically.By assuming an improvement of the heterointerface quality and an enhanced Al interdiffusion caused by postgrowth intermixings,the photoluminescence spectrum shows a blue-shifted,narrower and enhanced photoluminescence peak.The infrared optical absorption spectrum also shows the expected redshift of the response wavelength.However,the variation in the absorption peak intensity depends on the boundary conditions of the photo generated carriers.For high-quality QWIP samples,the mean free path of photocarriers is long so that the photocarriers are largely coherent when they transport across quantum wells.In this case,the enhanced Al interdiffusion can significantly degrade the infrared absorption property of the QWIP.Special effects are therefore needed to maintain and/or improve the optical properties of the QWIP device during postgrowth treatments. 展开更多
关键词 吸收光谱 量子阱 红外光电探测器 修正
下载PDF
Evaluation of Expression Recognition Function in Autism Spectrum Disorder Using Near-Infrared Spectroscopy 被引量:1
5
作者 Kaoru Furukawa Kenji Mori +4 位作者 Keiko Mori Saori Nakano Kumi Takahashi Hiroko Hashimoto Tetsuya Tanioka 《Open Journal of Psychiatry》 2018年第1期35-49,共15页
One of the characteristics of Autism Spectrum Disorder (ASD) is social disorder. The specificity of facial and expression recognition for people with ASD is gathering attention as a factor of this social disorder. The... One of the characteristics of Autism Spectrum Disorder (ASD) is social disorder. The specificity of facial and expression recognition for people with ASD is gathering attention as a factor of this social disorder. The study examined the hemodynamic activities in the prefrontal cortex using near-infrared spectroscopy (NIRS) when a person with ASD performed an expression recognition task. The subjects were twenty males (18 - 22 years old) with ASD and without intellectual disabilities. Forty-five healthy males matched for age and sex were included as a control group. In both groups, the degree of autistic tendencies was evaluated using the Autism-Spectrum Quotient (AQ). Using eight standard emotional expressions of Japanese people, two expression recognition tasks were set. An NIRS was used to measure the prefrontal cortex blood mobilization during the expression-processing process. The AQ was significantly higher in the ASD group, while the rate of overall correct expression response was significantly lower (p &rho;= &minus;0.40 p < 0.001). In the automatic expression-processing task, no activation in the prefrontal cortex was found in either the ASD or the control group. In the conscious expression-processing task, the activation of the left and right lateral prefrontal cortex was weaker in the ASD group compared to the control group. Unlike in the control group, a mild activation of posterior prefrontal cortex was found in the ASD group. The expression-processing process of the ASD group was found to be different from that of the control group. NIRS was effective in detecting a brain function disorder in people with ASD during an expression-processing process. 展开更多
关键词 AUTISM spectrum Disorder Near-infrared Spectroscopy Autism-spectrum QUOTIENT FACIAL Expression Recognition PREFRONTAL CORTEX
下载PDF
Detection of Chlorpyrifos Residues in Akesu Red Fuji Apple based on Near Infrared Spectrum
6
作者 Zhang Nannan Zhang Xiao 《Plant Diseases and Pests》 CAS 2018年第2期28-32,42,共6页
[Objective] The paper was to explore a method for detecting chlorpyrifos residues in red Fuji apple. [Method] The original spectral data of apple samples sprayed with different volume fractions of chlorpyrifos were co... [Objective] The paper was to explore a method for detecting chlorpyrifos residues in red Fuji apple. [Method] The original spectral data of apple samples sprayed with different volume fractions of chlorpyrifos were collected using near infrared spectrometer at the band of 4 000-10 000 cm^(-1). The original spectra were pre-treated by a variety of methods, and partial least squares(PLS) model was established for predictive analysis. [Result] Near infrared spectrum showed sensitivity to apple samples sprayed with different volume fractions of chlorpyrifos, but had low precision on pesticide-free samples. Data of blank control group were further eliminated for modeling prediction. The results showed that the results were the best when pre-treated with first derivative(FD): R=0.987 9; the square error of prediction(SEP) was 0.173 6; the root-mean-square error of cross-validation(RMSECV) was 0.120 5; and the precision was 0.923 4. [Conclusion] Near infrared spectrum can better predict chlorpyrifos residue, providing a new method for detecting chlorpyrifos residues in Akesu red Fuji apple. 展开更多
关键词 Near infrared spectrum Akesu red Fuji apple CHLORPYRIFOS Pesticide residue Partial least squares (PLS)
下载PDF
Global Optimization of Norris Derivative Filtering with Application for Near-Infrared Analysis of Serum Urea Nitrogen 被引量:2
7
作者 Yihui Yang Tao Pan Jing Zhang 《American Journal of Analytical Chemistry》 2019年第5期143-152,共10页
Near-infrared (NIR) spectroscopy combined with chemometrics methods was applied to the rapid and reagent-free analysis of serum urea nitrogen (SUN). The mul-partitions modeling was performed to achieve parameter stabi... Near-infrared (NIR) spectroscopy combined with chemometrics methods was applied to the rapid and reagent-free analysis of serum urea nitrogen (SUN). The mul-partitions modeling was performed to achieve parameter stability. A large-scale parameter cyclic and global optimization platform for Norris derivative filter (NDF) of three parameters (the derivative order: d, the number of smoothing points: s and the number of differential gaps: g) was developed with PLS regression. Meantime, the parameters’ adaptive analysis of NDF algorithm was also given, and achieved a significantly better modeling effect than one without spectral pre-processing. After eliminating the interference wavebands of saturated absorption, the modeling performance was further improved. In validation, the root mean square error (SEP), correlation coefficient (RP) for prediction and the ratio of performance to deviation (RPD) were 1.66 mmol?L-1, 0.966 and 4.7, respectively. The results showed that the high-precision analysis of SUN was feasibility based on NIR spectroscopy and Norris-PLS. The global optimization method of NDF is also expected to be applied to other analysis objects. 展开更多
关键词 NEAR-infrared Spectral ANALYSIS SERUM UREA Nitrogen Norris derivative Filter Norris-Partial Least SQUARES Global Optimization
下载PDF
Preparation of Ultrafine SiO2 Powder from Rice Husk and Properties of Its Infrared Spectrum
8
作者 晋日亚 胡双启 谭迎新 《Journal of Measurement Science and Instrumentation》 CAS 2011年第3期226-229,共4页
This paper discussed impact of temperature on the size distribution in preparing ultrafine silica from rice husk.The samples prepared were analyzed with infrared spectrum,and the relation between the particle size and... This paper discussed impact of temperature on the size distribution in preparing ultrafine silica from rice husk.The samples prepared were analyzed with infrared spectrum,and the relation between the particle size and intensity of characteristic absorption peak of IR at center around 1 100 cm-1 was disscussed with the baseline method.Results show that when the temperature is 650 ℃ and roasting time is 11 h,at optimal reaction conditions,the size distribution of the ultrafine silica powder prepared is relatively concentrated,and the average particle size is 199.5 nm.Moreover,the characteristic absorption band of IR is broadening gradually along with particle size decreasing. 展开更多
关键词 rice husk ultrafine powder SIO2 infrared spectrum
下载PDF
Signature of symmetry of laterally coupled quantum dots in far-infrared spectrum
9
作者 Gu Li-Ying Li Yan-Fang +1 位作者 Chu Wei-Dong Wei Ying-Hui 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第2期477-482,共6页
We study the effect of structure asymmetry on the energy spectrum and the far-infrared spectrum (FIR) of a lateral coupled quantum dot. The calculated spectrum shows that the parity break of coupled quantum dot resu... We study the effect of structure asymmetry on the energy spectrum and the far-infrared spectrum (FIR) of a lateral coupled quantum dot. The calculated spectrum shows that the parity break of coupled quantum dot results in more coherent superpositions in the low-lying states and exhibits unique anti-crossing in the two-electron FIR spectrum modulated by a magnetic field. We also find that the Coulomb correlation effect can make the FIR spectrum of coupled quantum dot without strict parity deviate greatly from Kohn theorem, which is just contrary to the symmetric case. Our results therefore suggest that FIR spectrum may be used to determine the symmetry of coupled quantum dot and to evaluate the degree of Coulomb interaction. 展开更多
关键词 structure symmetry far-infrared spectrum coupled quantum dot Coulomb interaction
下载PDF
基于机器视觉与光谱融合的柑橘品质无损检测分级系统设计与试验 被引量:5
10
作者 文韬 代兴勇 +1 位作者 李浪 刘豪 《江苏大学学报(自然科学版)》 CAS 北大核心 2024年第1期38-45,共8页
针对柑橘果径、着色率和内部糖度3项关键品质指标,基于双锥滚子式果杯传输线设计了一套柑橘综合品质无损检测分级系统,该系统主要包括喂料部分、机器视觉检测模块、近红外光谱检测模块和分级执行部分.机器视觉检测模块采用单相机拍摄不... 针对柑橘果径、着色率和内部糖度3项关键品质指标,基于双锥滚子式果杯传输线设计了一套柑橘综合品质无损检测分级系统,该系统主要包括喂料部分、机器视觉检测模块、近红外光谱检测模块和分级执行部分.机器视觉检测模块采用单相机拍摄不断翻滚的柑橘视频来获取大量不同姿态的柑橘图像,并进行轮廓提取,以单个柑橘所有帧图像的最小外接圆直径的平均值计算果径,以每一帧图像得到的其二维黄色占比的平均值作为全表面着色率.在近红外光谱检测模块中设计了透射式光路,采集柑橘透射率光谱,并按在线检测时柑橘出现的两种高频姿态建立了混合姿态糖度检测模型,对比不同预处理方法下的建模结果,选取应用效果较优的多元散射校正(MSC)后建立的偏最小二乘法(PLS)模型.在线试验结果表明:果径检测的最大绝对误差为-1.42 mm,着色率检测的最大绝对误差为0.048,糖度检测结果的相关系数为0.817,均方根误差为0.658%.内外品质的联合检测分级按判别树决策方法确定了3种品质的联合分级方式,在分选速度为5个/s时,综合分级的平均准确率可达到91.16%,该检测分级系统整体结构简单,对于类球形水果具有较强的适用性,在产业化应用上有很大的潜力. 展开更多
关键词 柑橘 无损检测 机器视觉 近红外光谱 分级
下载PDF
燃煤锅炉温度场与高温腐蚀气氛场同步在线检测装置开发及应用 被引量:1
11
作者 王建荣 程银雪 +6 位作者 李龙 郭古青 田亚莉 孙小聪 周月婷 李传亮 邱选兵 《电力科技与环保》 2024年第2期116-124,共9页
燃煤锅炉主燃区燃烧场的经济性、安全性和环保性对于智慧电厂建设具有重要意义。其中,水冷壁近壁面高温腐蚀H_(2)S和CO气体浓度的实时在线监测尤为重要。为实现燃煤锅炉主燃区温度场和高温腐蚀气氛场的同步测量,基于红外热成像原理,采用... 燃煤锅炉主燃区燃烧场的经济性、安全性和环保性对于智慧电厂建设具有重要意义。其中,水冷壁近壁面高温腐蚀H_(2)S和CO气体浓度的实时在线监测尤为重要。为实现燃煤锅炉主燃区温度场和高温腐蚀气氛场的同步测量,基于红外热成像原理,采用Optris-PI1M小型红外热成像仪,基于LabVIEW温度实时采集应用软件,在炉膛的观察口对主燃区温度场进行连续监测。以低成本1.5μm附近的通信波段激光器作为测量高温腐蚀气体H_(2)S和CO的激光光源,并结合波长调制光谱技术和频分复用技术,以实现H_(2)S和CO气体浓度的同步检测。线性度实验表明,其线性拟合相关系数为0.9995。将研制的同步检测仪器对某300 MW四角切圆燃煤锅炉的主燃区的温度场和气氛场进行了现场应用试验。现场测试结果表明,锅炉主燃区温度主要分布范围在1300~1400℃,最高温度达到了1500℃;同时得到了锅炉主燃区的H_(2)S和CO浓度分布,H_(2)S浓度在12~125 mg/m^(3)的范围内波动,而CO浓度主要分布在10%~20%之间,最高可达22%;炉内H_(2)S和CO的浓度呈正相关,氧气浓度保持在1%以下,由于厌氧燃烧会导致两种气体的含量增加,从而造成对水冷壁近壁面的高温腐蚀。 展开更多
关键词 燃煤锅炉 高温腐蚀 红外热成像 激光吸收光谱 在线监测
下载PDF
近红外光谱联合化学计量学在柑橘类水果质量无损检测方面的最新研究及应用进展
12
作者 李晋 张琛 +2 位作者 刘红 张伟清 何鸿举 《食品与发酵工业》 CAS CSCD 北大核心 2024年第5期367-379,共13页
柑橘类水果以其诱人的风味和高保健作用而备受消费者青睐。面对日益增长的市场份额,以及对口感、质量的双重需求,高品质柑橘类水果成为消费偏爱。快速检测技术的研发应用可为柑橘类水果的安全生产和消费保驾护航。近红外(near-infrared,... 柑橘类水果以其诱人的风味和高保健作用而备受消费者青睐。面对日益增长的市场份额,以及对口感、质量的双重需求,高品质柑橘类水果成为消费偏爱。快速检测技术的研发应用可为柑橘类水果的安全生产和消费保驾护航。近红外(near-infrared,NIR)光谱技术作为一种无损、便捷、高效的绿色检测技术,已被广泛用于水果质量检测研究。文章全面归纳综述了近5年来NIR光谱技术结合化学计量学在柑橘类水果内部成分、外部缺陷、活性物质、病害、品种、分类、产地等方面的检测研究及应用进展,阐明了NIR光谱技术在柑橘类水果质量检测应用方面的发展趋势并提出了相关建议,为完善光谱技术检测柑橘类水果理论和研发专用水果检测设备提供方法借鉴。 展开更多
关键词 近红外 光谱 柑橘 检测 品质
下载PDF
电力用油红外光谱检测技术
13
作者 王娟 付龙飞 +7 位作者 王笑微 吕秀娟 曹红梅 王垚 张兰庆 康夜雨 潘成福 齐吉锴 《热力发电》 CAS CSCD 北大核心 2024年第2期177-183,共7页
红外光谱检测技术因其检测速度快、对样品无损伤、无污染、易操作等特点,已广泛应用于石油化工、制药等行业的检测中。红外光谱检测方式主要包括定性检测和定量检测,定性检测通常采用比较法,即通过与标准物质对照或查阅标准谱图;定量检... 红外光谱检测技术因其检测速度快、对样品无损伤、无污染、易操作等特点,已广泛应用于石油化工、制药等行业的检测中。红外光谱检测方式主要包括定性检测和定量检测,定性检测通常采用比较法,即通过与标准物质对照或查阅标准谱图;定量检测是通过测量特征吸收谱带强度,结合化学计量学方法计算出对应组份含量。阐述了人工神经网络、偏最小二乘法等化学计量学方法在电力用油酸值、水分、抗氧化剂、糠醛等检测中的应用,并对其在油品检测中的应用给出了建议。 展开更多
关键词 红外光谱 电力用油 酸值 水分 抗氧化剂
下载PDF
盘锦地区不同品种水稻品质及其冠层高光谱反射率特征分析
14
作者 王岩 高美琦 +4 位作者 卞景阳 李荣平 赵先丽 温日红 张东奎 《气象与环境学报》 2024年第2期77-85,共9页
对2022年盘锦地区8种水稻进行品质特征分析,并探讨不同品种水稻籽粒加工品质、外观品质、蒸煮品质、营养品质与水稻成熟期冠层原始光谱、一阶导数光谱及连续统去除光谱的相关关系。结果表明:盐粳939的加工品质较好,锦稻106(9系)的外观... 对2022年盘锦地区8种水稻进行品质特征分析,并探讨不同品种水稻籽粒加工品质、外观品质、蒸煮品质、营养品质与水稻成熟期冠层原始光谱、一阶导数光谱及连续统去除光谱的相关关系。结果表明:盐粳939的加工品质较好,锦稻106(9系)的外观品质较好,锦稻香103的蒸煮品质较好,盘粳968(3系)的营养品质较好。原始光谱反射率与糙米率指标的相关关系较好,在731~1131 nm和1150~1360 nm两个波段内,相关系数高达0.767;糙米率与一阶导数光谱的相关关系最好,在1459 nm处达到极显著相关,相关系数为0.867;垩白度和垩白粒率均在1804 nm处与连续统去除光谱的相关关系较好,并达到极显著负相关,相关系数分别为-0.979和-0.983;长宽比与原始光谱的相关关系较好,相关系数在659 nm处达到最大值,为0.849;蒸煮品质所包含的食味值、直链淀粉含量和营养品质所包含的蛋白质含量均与连续统去除光谱有较好的相关关系。 展开更多
关键词 水稻籽粒品质 冠层光谱反射率 一阶导数光谱 连续统去除光谱
下载PDF
玉米秸秆纤维素的提取及其对沥青性能影响的研究
15
作者 程培峰 张雪 +1 位作者 李艺铭 王洋弘历 《功能材料》 CAS CSCD 北大核心 2024年第8期8111-8119,共9页
纤维素作为秸秆的重要组成部分,是决定其力学强度的关键。若将其应用于沥青路面中,有望改善路面的性能并解决秸秆在路面中易产生降解、老化等问题。研究首先利用星点设计-效应面法,探究了秸秆中纤维素的提取工艺对沥青性能的影响,并确... 纤维素作为秸秆的重要组成部分,是决定其力学强度的关键。若将其应用于沥青路面中,有望改善路面的性能并解决秸秆在路面中易产生降解、老化等问题。研究首先利用星点设计-效应面法,探究了秸秆中纤维素的提取工艺对沥青性能的影响,并确定了纤维素的最佳提取工艺;然后,通过流变性能试验、离析试验以及红外光谱试验分析,研究了纤维素对沥青高温稳定性、低温抗裂性及储存稳定性的影响。结果表明,在NaOH浓度为2.5%,HNO_(3)浓度为4.3%的条件下所提取的纤维素对沥青物理性能的改善效果最佳,同时,玉米秸秆纤维素的掺入提高了沥青的高温稳定性、低温抗裂性以及在高速车辆荷载剪切作用下的抗变形能力。当玉米秸秆纤维素的掺量为7%时,沥青的综合性能最佳,未产生严重的离析现象。与基质沥青相比,纤维素掺量在7%时的高温连续分级温度(T_(LH))提升了13℃,低温性能提升了49.3%。此外,纤维素仅以物理增强作用互相粘结改善沥青的性能,并未发生化学反应。 展开更多
关键词 道路工程 纤维素的提取 改性沥青 流变性能 红外光谱
下载PDF
基于红外辐射测温法的焊头动态高速真温测量系统研制
16
作者 萧鹏 台泓冰 +2 位作者 向茂林 王伟宸 张帆 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第3期836-842,共7页
温度是用来表征物体特性的一个重要的基本参数,被广泛应用于金属加工、生产生活、航空航天等各个领域,温度测量的准确与否对每个行业都有着至关重要的影响。随着电子设备的尺寸不断微型化以及各种可穿戴智能设备的普及和发展,小型化成... 温度是用来表征物体特性的一个重要的基本参数,被广泛应用于金属加工、生产生活、航空航天等各个领域,温度测量的准确与否对每个行业都有着至关重要的影响。随着电子设备的尺寸不断微型化以及各种可穿戴智能设备的普及和发展,小型化成为了电子元件技术水平的一个重要技术指标,所以电子元器件也一直朝着小尺寸、高集成化方向发展,而其焊接温度的波动引起的产品良品率也在不断降低。因此,如何实现电子元器件焊接过程中焊头温度的实时获取,已成为众多相关企业急需研究的课题。基于晶体管式焊接电源的工作特点,从分析焊头的结构特性入手,利用焊头的红外光谱辐射特性,设计了一种激光瞄准式的光学系统,采用朗伯体法对焊头进行温度测量,从而得到焊头工作时的实时真温。整个温度测量系统由硬件系统部分和软件系统部分构成。其中,硬件系统包括光学系统的设计、 I/V转换及放大电路和上位机的高速数据采集系统。软件系统主要包括上位机系统界面的设计。上位机软件采用LabVIEW进行程序设计,主要包括AD采集卡的配置与驱动、数据滤波、零点测量、温度标定、温度计算、实时温度曲线和数据存储。在系统建立、软件调试完毕后,采用标准空腔黑体炉对测温系统进行了校准。首先,利用整体黑体法对焊头工作时的发射率进行了试验,结果表明,在氧化和非氧化状态下,其发射率与文献数据基本一致。然后利用该发射率值,计算出了焊头上小孔的空腔黑体发射率。最后,利用恒流晶体管式焊接电源进行了系统稳定性和重复性实验。分析该方法的不确定度,得出该方法的总体不确定度在3%以内。通过对测温系统的标定和配置,该系统还可以应用在其他需要高速精确测温的场景。 展开更多
关键词 焊头温度 黑体法测温 快速测量 红外光谱 发射率
下载PDF
拉曼光谱与中红外光谱融合技术快速定量食用酒精的乙醇浓度
17
作者 孙晓荣 闫思宁 +2 位作者 刘翠玲 张善哲 胡毅然 《食品安全质量检测学报》 CAS 2024年第8期208-218,共11页
目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷... 目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷积平滑(Savitzky-Golay,S-G)、一阶求导的方法对原始数据进行预处理。然后,基于自举软缩减法(bootstrapping soft shrinkage,BOSS)和无信息变量消除算法(uninformative variable elimination,UVE)分别对预处理后的光谱数据进行特征提取,并利用X-Y距离样本集划分法(sample set partitioning based on joint X-Y distance,SPXY)将光谱数据划分为校正集和预测集。最后,建立基于拉曼光谱-中红外光谱数据融合的偏最小二乘回归(partial least squares regression,PLSR)食用酒精乙醇浓度预测模型,并利用麻雀搜寻算法优化的混合核极限学习机算法(sparrow search algorithm-optimized hybrid kernel extreme learning machine,SSA-HKELM)提升预测性能,实现对不同浓度食用酒精的快速、准确定量检测。结果与拉曼光谱数据、中红外光谱数据以及中红外与拉曼光谱的数据层融合构建的预测模型相比,中红外光谱与拉曼光谱特征层融合数据构建的预测模型具有更好的预测性能。其中,最优模型的校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.98314,校正集决定系数(R_(c)^(2))为0.99634,预测集均方根误差(root mean squared error of prediction set,RMSEP)为1.03256,预测集决定系数(R_(p)^(2))为0.99036。结论中红外光谱与拉曼光谱特征层融合预测模型可以实现对不同浓度食用酒精的高效定量检测,为食用酒精的质量检测提供了有效的理论支持与技术保障。 展开更多
关键词 拉曼光谱 中红外光谱 光谱数据融合 乙醇溶液
下载PDF
基于红外光谱与多种预处理组合的柴油纯度检测方法
18
作者 周围 李安吉 +3 位作者 俞铁铖 尹冉 赵丽娟 赵美琪 《精细石油化工》 CAS 2024年第1期32-37,共6页
利用红外光谱技术采集51种不同体积分数的柴油光谱数据,采用主成分马氏距离法剔除异常样本,通过71种预处理组合及偏最小二乘法建立了柴油纯度性质模型。结果表明:合理预处理后的建模效果明显优于未经预处理的效果,预测均方根误差(RMSEP... 利用红外光谱技术采集51种不同体积分数的柴油光谱数据,采用主成分马氏距离法剔除异常样本,通过71种预处理组合及偏最小二乘法建立了柴油纯度性质模型。结果表明:合理预处理后的建模效果明显优于未经预处理的效果,预测均方根误差(RMSEP)降到了0.0400以下,相关系数(R_(p))达到了0.9900以上,且预处理组合方法的顺序不同,其建模效果即模型评价指标RMSEP、R_(p)也不同;1stderivative+SNV、1^(st) derivative+SNV+center、1^(st) derivative+center+SNV、center+1stderivative+SNV这4种预处理组合方法的模型预测效果最好,RMSEP可达0.0187,R_(p)可达0.9978,可适用于柴油纯度光谱数据的处理,实现柴油纯度的检测。 展开更多
关键词 柴油纯度 红外光谱 预处理组合 偏最小二乘
下载PDF
天然红宝石结构的原位漫反射中红外光谱研究 被引量:2
19
作者 于宏伟 柴嘉欣 +3 位作者 吉一帆 宗雪晴 张泽旺 吴雨靓 《玻璃搪瓷与眼镜》 CAS 2024年第4期10-14,共5页
利用原位漫反射中红外光谱研究天然红宝石的结构,发现红宝石结构的红外吸收模式主要包括:α-Al_(2)O_(3)分子中O^(2-)对静止Al^(3+)位移对应的红外吸收模式(ν_(α-Al_(2)O_(3)-O-Al))、Cr_(2)O_(3)分子中O^(2−)对静止Cr^(3+)位移对应... 利用原位漫反射中红外光谱研究天然红宝石的结构,发现红宝石结构的红外吸收模式主要包括:α-Al_(2)O_(3)分子中O^(2-)对静止Al^(3+)位移对应的红外吸收模式(ν_(α-Al_(2)O_(3)-O-Al))、Cr_(2)O_(3)分子中O^(2−)对静止Cr^(3+)位移对应的红外吸收模式(ν_(Cr_(2)O_(3)-O-Cr))、Fe_(2)O_(3)分子中O_(2)−对静止Fe3+位移对应的红外吸收模式(ν_(Fe_(2)O_(3)-O-Fe))、α-Al_(2)O_(3)分子中Al^(3+)之间位移对应的红外吸收模式(ν_(α-Al_(2)O_(3)-Al-Al))及锌尖晶石特征红外吸收模式(νZnAl_(2)O4);红宝石的主要结构包括:α-Al_(2)O_(3)、Cr_(2)O_(3)、Fe_(2)O_(3)及少量共生锌尖晶石。采用原位漫反射中红外光谱,研究小颗粒红宝石类矿物结构具有重要的应用价值。 展开更多
关键词 红宝石 原位漫反射 红外光谱 α-Al_(2)O_(3) Cr_(2)O_(3) Fe_(2)O_(3) 锌尖晶石
下载PDF
沥青老化前后宏-微观性能相关性
20
作者 郭猛 何舒欣 +2 位作者 龚演 严二虎 梁美琛 《交通运输研究》 2024年第1期58-69,共12页
为探索沥青老化过程中微观结构变化对其宏观力学性能的内在影响机制,结合动态剪切流变仪测定的流变学参数与红外光谱仪及荧光显微镜获取的化学官能团和微观结构数据,揭示了基质沥青与SBS改性沥青在不同老化阶段的宏-微观性能关联。研究... 为探索沥青老化过程中微观结构变化对其宏观力学性能的内在影响机制,结合动态剪切流变仪测定的流变学参数与红外光谱仪及荧光显微镜获取的化学官能团和微观结构数据,揭示了基质沥青与SBS改性沥青在不同老化阶段的宏-微观性能关联。研究发现,SBS改性沥青的微观空间网络结构赋予其卓越的黏弹特性。识别了SBS改性剂特有的红外光谱特征峰,为快速识别和评估SBS改性沥青提供了一种方法。通过灰色关联度分析,发现官能团指数与复数剪切模量的关联度排序为:亚砜基官能团指数>芳香环官能团指数>羰基官能团指数,与沥青表面能的关联度顺序为:芳香环官能团指数>羰基官能团指数>亚砜基官能团指数。研究进一步证实,沥青老化过程中官能团的氧化和微观形貌的重构是影响其复数剪切模量变化的关键因素,为沥青材料的老化行为提供了新的理论解释。 展开更多
关键词 沥青老化 流变力学 荧光显微镜 红外光谱 表面能 灰色关联分析
下载PDF
上一页 1 2 237 下一页 到第
使用帮助 返回顶部