Nature of intrinsic and impure luminescence of MAlP2O7 crystals

The results of the photoluminescence (PL) investigation of pure and chromium-doped MAlP₂O₇ (M = Na, K, Cs) compounds are presented. The spectra of the intrinsic luminescence of MAlP₂O₇ crystals consist of a separated UV band at a peak position near 330 nm and a complex wide band which covers the region of visible light up to 750 nm at excitation by VUV synchrotron radiation. The “red” band in 600–1000 nm diapason appears in the PL spectra of crystals doped with chromium ions. The effect of the temperature on the structure, the peak positions and intensities of the luminescence bands was studied. An assumption about the nature of the intrinsic PL was made. The “red” luminescence was considered as a result of the ⁴Т₂ → ⁴А₂ radiation transitions in the impurity Cr³⁺ ions located in the intermediate crystal field.     

一种肿瘤基因表达数据的知识提取方法

本文以多发性骨髓瘤的基因表达数据为例,利用数据挖掘技术,提出了一种针对基因表达数据进行知识发现的方法.该方法通过计算基因的信息增益,结合神经网络,找出了特征基因集合,最后利用决策树进行特征规则的提取,给出了基于多发性骨髓瘤数据样本的产生式规则,为生物医学研究提供了一种分析和研究基因表达数据的参考方法.实验结果表明了该方法的有效性.     

Quantum dot sensitized solar cell based on poly (3-hexyl thiophene)/CdSe nanocomposites

The optoelectronic properties of P3HT–CdSe nanocomposites prepared by insitu chemical oxidative polymerization were studied. CdSe QDs were synthesized by hot injection method using tri octyl phosphine oxide (TOPO) as capping ligand whereas the P3HT polymer was prepared by chemical oxidative polymerization. FTIR studies confirmed the regioregularity of the P3HT and revealed the chemical interaction of P3HT and CdSe in nanocomposite. Absorption studies showed blue shift for the nanocomposites as compare to pristine P3HT, the electron transfer from conducting polymer to the CdSe was detected by the measurements of quenching of photoluminescence from conducting polymer after the addition of semiconductor nano crystals which confirmed that an optimum amount of nanoparticles provide networking in hybrid composites. The optimal result for device prepared by P3HT–CdSe nanocomposites was open circuit voltage (V_oc) 0.5, short circuit current density (J_sc) 0.66, Fill factor (FF) 0.6855 and efficiency (η) 0.22%.     

Laser cooling of solids containing local centers with electric dipole allowed transitions: a feasibility study

Various insulating materials containing local centers with electric dipole allowed transitions were studied under excitation in the long-wavelength tail of the absorption spectrum (“laser cooling regime”). Though no actual cooling was detected, spectra with a strong anti-Stokes component were observed which demonstrate the possibility to employ electron–phonon bands of electric dipole allowed transitions for optical refrigeration. The mechanisms responsible for the absence of observable optical refrigeration are discussed.     

融合DCLBP和HOAG特征的人脸表情识别方法

为了进一步提高人脸表情识别算法的准确性,提出一种融合双编码局部二值模式(DCLBP)算子和绝对梯度直方图(HOAG)算子的人脸表情识别方法,该方法首先利用DCLBP算子提取人脸图像的局部纹理特征,利用HOAG算子提取人脸图像的局部形状特征;然后,采用典型相关分析法(CCA)融合所提取的两种特征;最后,利用支持向量机(SVM)进行人脸表情分类。实验结果表明,与单一特征识别方法和级联特征识别方法相比,本文方法获得了更好的识别效果,在CK (Cohn-Kanade)和JAFFE数据集上的实验分别达到了100%和99.05%的识别率,与其他相关方法的比较也验证了其有效性。     

融合边缘检测和递归神经网络的视频表情识别

为有效解决传统视频人脸表情识别通常只关注单张视频帧的空间特征,而忽略了相邻帧之间隐藏的时间特征的问题,提出一种结合边缘检测和递归神经网络的视频表情识别方法,利用梯度边缘检测准确地提取输入图像的纹理信息,同时提出一种分片交叉LSTM结构,提取出图像序列中隐藏的时空特征。实验在CK+和MMI视频库上进行,在OCNN-RNN网络中分别取得88.4%和69.7%的识别率,在GCNN-RNN网络中分别取得89.8%和73.6%的识别率,最终使用提出的加权随机搜索方法融合GCNN-RNN和OCNN-RNN两个网络之后,分别取得了94.6%和79.9%的识别率,均优于单流网络算法,证明了所提算法的有效性。     

A Novel Approach for Diagnosis of Analog Circuit Fault by Using GMKL-SVM and PSO

This paper presents a novel analog circuit fault diagnosis approach using generalized multiple kernel learning-support vector machine (GMKL-SVM) method and particle swarm optimization (PSO) algorithm. First, the wavelet coefficients’ energies of impulse responses are generated as features. Then, a diagnosis model is constructed by using GMKL-SVM method based on features. Meanwhile, the PSO algorithm yields parameters for the GMKL-SVM method. Sallen-Key bandpass filter and two-stage four-op-amp biquad lowpass filter fault diagnosis simulations are given to demonstrate the proposed diagnose procedure, and the comparison simulations reveal that the proposed approach has higher diagnosis precision than the referenced methods.     

基于AAM-SIFT特征描述的两级SVM人脸表情识别

采用AAM定位特征点、尺度不变特征变换（SIFT）描述特征的方式提出一种基于AAM-SIFT的表情特征提取方法。该方法用特征点周围区域梯度方向直方图描述表情特征;同时根据不同子区域对表情的贡献不同,将特征点分组并赋予不同权重,并用两级支持向量机（SVM）对融合的加权特征进行分类识别。在标准表情库和多姿态表情库上的验证结果表明,该方法能有效提高正面人脸表情的识别率,对一定偏转角度的非正面人脸表情也保持较好的鲁棒性。     

Design,implementation, and evaluation of a game-based application for aiding chemical engineering and chemistry students to review the organic reactions

This article presents a multilingual (Portuguese, Spanish, English, and French) game-based application to the Android and the iOS platforms. The game allows undergraduate Chemical Engineering and Chemistry students to individually review organic reactions in an engaging and fun way by answering over 600 multi-choice questions. Undergraduate students tested and evaluated the game, and their opinions revealed that they liked to use the game as a complementary educational tool able to aid them in their studies. Moreover, the usability assessment of the game provided a good SUS score close to 79.     

A Hybrid Modeling Method Based on Linear AR and Nonlinear DBN-AR Model for Time Series Forecasting

Neural Processing Letters - Improving time series forecasting accuracy is an important work for decision makers. A single model applied on a data series may not obtain satisfactory prediction...