Nanoporous anodic aluminium oxide (AAO) films with a large-range tunable interpore distance (Dint) and unique microstructures have been fabricated by high voltage anodization (140–400 V) in 0.3 M oxalic acid electrolyte. The influences of anodization conditions (e.g., anodization voltage (Ua) and current density (ia)) on the microstructures of AAO films have been investigated in detail. Experimental results show that there is a linear relationship between Ua and Dint under relatively low Ua. With the increase of Ua, the influences of ia and dehydration of aluminium hydroxide on the Dint may not be ignored, thus resulting in a nonlinear relationship between Ua and Dint. When the anodization is performed at an excessively high Ua of 400 V, an interesting competitive growth of nanochannels inside the AAO film tends to occur, thus forming an AAO film with unique nano/micro morphology at the barrier layer side.
In multiplesound-sources environment, robustness is a major challenge for audio recognition system based on audio fingerprinting, because mixed audio signals may make recognition rate has a significant decline.This paper proposes a novel audio fingerprinting method, which uses blind source separation to divide mixed audio signals into independent components and each is close to its original sound-source, then the classical Philips scheme can perform accurately identifying.Experimental results show that novel scheme is quite robust in noisy conditions where uncertain audio signals mixed by various numbers of sound-source, even though the feature of each original sound-source and their mixed model are unknown.
Air-coupled ultrasonic testing is a possible implementation method for online seal defect detection of flexible package. However, large acoustic impedance difference between air and solid material leads to difficulties in coupling ultrasonic energy into solid materials and results in a poor signal to noise ratio (SNR). To solve this problem, pulse compression technique based on Golay codes has been applied in air-coupled ultrasonic testing of flexible package seal defect. The effects of different Golay codes (4, 8 and 16 bits) and Golay codes with different bit length (1, 2, and 3 circles) are investigated to obtain a reasonable parameter selection. The results demonstrate that the Golay coded pulse compression technique can improve the SNR ratio of the received signal remarkably, and suppressed the side lobe of the compressed pulse effectively. An improvement in SNR of the seal region image up to 9.4 dB is achieved, compared with the non-modulated excitation method.
Hyperspectral imaging combined with chemometric approaches is proven to be a powerful tool for the quality evaluation and control of fruits. In fruit defect-detection scenarios, developing an unsupervised anomaly detection framework is vital, as defect sample preparation is labor-intensive and time-consuming, especially for exploring potential defects. In this paper, a spectral-spatial, information-based, self-supervised anomaly detection (SSAD) approach is proposed. During training, an auxiliary classifier is proposed to identify the projection axes of principal component (PC) images that were transformed from the hyperspectral data cubes. In test time, the fully connected layer of the learned classifier was used as a 'spectral-spatial' feature extractor, and the feature similarity metric was adopted as the score function for the downstream anomaly evaluation task. The proposed network was evaluated with two fruit data sets: a strawberry data set with bruised, infected, chilling-injured, and contaminated test samples and a blueberry data set with bruised, infected, chilling-injured, and wrinkled samples as anomalies. The results show that the SSAD yielded the best anomaly detection performance (AUC = 0.923 on average) over the baseline methods, and the visualization results further confirmed its advantage in extracting effective 'spectral-spatial' latent representation. Moreover, the robustness of SSAD is verified with the data pollution experiment; it performed significantly better than the baselines when a portion of anomalous samples was involved in the training process.
Among 50 CLE gene family members in the Populus trichocarpa genome, three and six PtCLE genes encode a CLE motif sequence highly homologous to Arabidopsis CLV3 and TDIF peptides, respectively, which potentially make them functional equivalents. To test and compare their biological activity, we first chemically synthesized each dodecapeptide and analysed its in vitro bioactivity on Arabidopsis seedlings. Similarly, but to a different extent, three types of poplar CLV3-related peptides caused root meristem consumption, phyllotaxis disorder, anthocyanin accumulation and failure to enter the bolting stage. In comparison, application of two poplar TDIF-related peptides led to root length promotion in a dose-dependent manner with an even stronger effect observed for poplar TDIF-like peptide than TDIF. Next, we constructed CaMV35S:PtCLE transgenic plants for each of the nine PtCLE genes. Phenotypic abnormalities exemplified by arrested shoot apical meristem and abnormal flower structure were found to be more dominant and severe in 35S:PtCLV3 and 35S:PtCLV3-like2 lines than in the 35S:PtCLV3-like1 line. Disordered vasculature was detected in both stem and hypocotyl cross-sections in Arabidopsis plants over-expressing poplar TDIF-related genes with the most defective vascular patterning observed for TDIF2 and two TDIF-like genes. Phenotypic difference consistently observed in peptide application assay and transgenic analysis indicated the functional diversity of nine poplar PtCLE genes under investigation. This work represents the first report on the functional analysis of CLE genes in a tree species and constitutes a basis for further study of the CLE peptide signalling pathway in tree development.
Alumina nanotubes (ANTs) with unique fusiform morphologies were synthesized via a simple electrochemical route; the fluctuation of the electronic current density during the anodization process is considered to be the main reason for the formation of such new alumina nanostructures.
A novel and efficient method for the synthesis of arylboronic acid pinacol esters via a palladium- or iron-catalyzed cross-coupling reaction of aryl fluorides with bis(pinacolato)diboron (B2pin2) in the presence of LiHMDS was developed. The Pd-catalyzed defluoroborylation of fluoroarenes is compatible with a variety of functional groups such as primary and secondary amine, ketone, trifluoromethyl, alkoxy, and boryl. Remarkably, no external ligand is required for enhanced conversion efficiency.
Puerariae Lobatae Radix, the dried root of Pueraria lobata, is a traditional Chinese medicine with a long history. Puerariae Lobatae Caulis as an adulterant is always mixed into Puerariae Lobatae Radix for sales in the market. This study employed hyperspectral imaging(HSI) to distinguish between the two products. VNIR lens(spectral scope of 410-990 nm) and SWIR lens(spectral scope of 950-2 500 nm) were used for image acquiring. Multi-layer perceptron(MLP), partial least squares discriminant analysis(PLS-DA), and support vector machine(SVM) were employed to establish the full-waveband models and select the effective wavelengths for the distinguishing between Puerariae Lobatae Caulis and Puerariae Lobatae Radix, which provided technical and data support for the development of quick inspection equipment based on HSI. The results showed that MLP model outperformed PLS-DA and SVM models in the accuracy of discrimination with full wavebands in VNIR, SWIR, and VNIR+SWIR lens, which were 95.26%, 99.11%, and 99.05%, respectively. The discriminative band selection(DBS) algorithm was employed to select the effective wavelengths, and the discrimination accuracy was 93.05%, 98.05%, and 98.74% in the three different spectral scopes, respectively. On this basis, the MLP model combined with the effective wavelengths within the range of 2 100-2 400 nm can achieve the accuracy of 97.74%, which was close to that obtained with the full waveband. This waveband can be used to develop quick inspection devices based on HSI for the rapid and non-destructive distinguishing between Puerariae Lobatae Radix and Puerariae Lobatae Caulis.
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