基于可见-近红外光谱技术与BP-ANN算法的污水类型鉴定

提出了一种基于可见-近红外光谱技术与BP人工神经网络(BP-ANN)算法快速进行污水类型鉴定的新方法.以FieldSpec(R)3地物光谱仪采集了4种污水样品的光谱数据,共168份,随机将其分成校正集(132份)和检验集(36份).分别采取全波段(400～2450 nm)与择取波段(400～1800 nm)两种方法建立模型进行分析.光谱经S.Golay平滑和标准归一化(SNV)处理后,以主成分分析法(PCA)降维.将降维所得的前9个主成分数据作为BP-ANN的输入变量,污水类型作为输出变量,建立3层BP-ANN鉴别模型.利用36个未知样对模型进行检验.结果表明:两类模型预测准确率均高达100%,且择取波段模型比全波段模型具有更高的预测精度.说明利用可见-近红外技术结合BP-ANN算法进行污水类型的快速、无污染鉴定是可行的,且波段筛选是优化模型的有效方法之一.     

大鼠射频损毁治疗靶点脑局部血氧饱和度(SO2)变化特性研究

神经外科脑毁损术中靶点局部生理参数实时监控非常重要,目前手术疗效还没有一种可靠的实时评估指标,我们将对此进行初步探索。采用 SD大鼠为实验对象,对大鼠脑部治疗靶点进行局部射频毁损,利用微创近红外光谱技术实时测量局部血氧饱和度,考察其毁损过程中的变化规律。实验结果表明血氧饱和度在可逆与不可逆毁损时表现出不同的变化特性,通过对实验数据的统计分析,找到了一些基本规律,这些结果对立体定向射频毁损实时疗效评估具有一定的参考价值。     

Tb3+、Yb3+共掺BaGd2ZnO5荧光粉的制备及其近红外量子剪裁研究

采用高温固相法合成了Tb3+、Yb3+共掺杂的BaGd2ZnO5荧光粉。XRD测量数据表明合成的样品为纯相。在Tb3+特征激发(297 nm)下得到了Yb3+的特征发射(977 nm),并且对Tb3+与Yb3+能级图进行分析,证明Tb3+到Yb3+为合作能量传递。测量了不同Yb3+浓度下Tb3+的5D4能级(544 nm)的发光寿命曲线,计算得到Tb3+与Yb3+的能量传递效率和量子效率,最高量子效率为125.5%。Yb3+的发射与硅太阳能电池的吸收匹配,该材料有可能应用于硅太阳能电池以提高其转换效率。     

PVK空穴传输层对Ndq3近红外发光二极管性能的影响

以PEDOT∶PSS作为空穴注入层,聚合物PVK作为空穴传输层,制备了结构为ITO/PEDOT∶PSS/PVK/8-羟基喹啉钕(Ndq3)/Al的近红外OLED,研究了PVK与PEDOT∶PSS功能层对器件I-V特性和EL光谱的影响。结果显示,在EL光谱中的905,1 064,1 340 nm处均观察到了荧光发射,分别对应于Nd3+的4F3/2→4I9/2、4F3/2→4I11/2和4F3/2→4I13/2能级跃迁。与参考器件对比分析认为,PEDOT∶PSS高的导电性降低了器件的串联电阻,增大了器件的工作电流;PVK与PEDOT∶PSS共同降低了空穴的注入势垒,实现了Ndq3发光层区域的载流子的注入平衡并改善了器件的发射强度。此外,PVK有效降低了ITO电极表面粗糙度,也是器件性能提高的原因之一。     

Near Infrared Studies of Polymer Blends

Abstract

The dependence of absorption in the near-infrared region of cellulose acetate-polyaniline/camphorsulfonic acid blends on their conductivity and homogeneity has been studied. Thin films (10 to 100 μm) of the blends containing various amounts of protonated polyaniline show very high absorption in the NIR region. The absorption increases with increasing of conductivity and homogeneity of the sample.     

Investigation of the Kinetics of Curing Reaction for the Resin Matrix Polymer Composite Based on Near-Infrared Spectroscopy

Abstract

Near-infrared (NIR) spectroscopy is a rapid and nondestructive method for the simultaneous measurement of different constituents in resin matrix polymer composites. This strategy has been applied in the synthesis of resin matrix polymer composites. In this article, we mainly review the control of curing reaction kinetics of the phenolic, epoxy resin, polyester resin, polyurethane, and other polymer resin based on NIR spectra, which is important to control the quality of the resin matrix polymer composites during synthesis.     

Secondary Ion Mass Spectrometry Imaging

Secondary ion mass spectrometry (SIMS) is a chemical analysis technique that employs mass spectrometry to analyze solid and low volatility liquid samples [1]. Although there are numerous configurations of SIMS instrumentation, the fundamental basis of SIMS analyses is the measurement of the mass and intensity of secondary ions produced in a vacuum by sputtering the surface of the sample with energetic ion or neutral beams. The sputtering beam is referred to as the primary beam and typically has a kinetic energy of several thousand electronvolts (keV). The primary beam removes atomic or molecular layers at a rate determined principally by the intensity, mass, and energy of the primary species and the chemical and physical characteristics of the sample [2]. Particle sputtering at the kiloelectronvolt level produces a variety of products including electrons, photons, atoms, atomic clusters, intact molecules, and distinctive molecular fragments. A small fraction of these sputter products are ionized, and these ions are the secondary ions in secondary ion mass spectrometry.     

InGaAs近红外相机电路设计与实现

随着国外0.9～1.7μm InGaAs近红外相机的迅速发展,目前已被大量应用于工业和军事领域。探讨了InGaAs近红外相机在不同领域的应用,分析了InGaAs材料的优势及探测器选型。结合相应的探测器阵列,从相机偏置电压产生、时序驱动设计与制冷控制等方面给出了InGaAs近红外相机的硬件电路设计方案,解决了研制过程中的部分重难点,并针对后期图像处理进行了仿真验证,达到应用要求。     

Establishment of an integrated data fusion method between the colorimeter and near-infrared spectroscopy to discriminate the stir-baked Gardenia jasminoides Ellis

Stir-heating is a common method to process Gardenia jasminoides Ellis. The processing of the G. jasminoides Ellis which do not meet the regulated requirements can result in the unqualified products, finally decreasing the efficacy of the drug. To guarantee the quality of the stir-baked G. jasminoides Ellis, a rapid and efficient method to discriminate the qualified stir-baked G. jasminoides Ellis from the unqualified was developed based on the middle level data fusion. 61 batches of qualified and unqualified stir-baked G. jasminoides Ellis were collected and analyzed using colorimeter and near-infrared spectroscopy, separately. L*, A*, and B* were apparent features that quantitatively described the characteristics of samples. The latent variables of partial least squares discriminant analysis model were extracted as the features of near-infrared spectroscopy. The extracted features from colorimeter and near-infrared spectroscopy were fused and a discriminant model was built using partial least squares discriminant analysis method. Accuracy, sensitivity, and specificity were used to evaluate the ability of classification. As a result, the accuracy, sensitivity, and specificity of the optimal partial least squares discriminant analysis model based on fused data were all equal to 1. It demonstrated that the developed method can be capable of discriminating the qualified stir-baked G. jasminoides Ellis from the unqualified. Compared with classification model results using color parameters or near infrared data alone, this data fusion strategy greatly improved the accuracy of classification.