Search

Due to the limitations imposed by urban power grid outages for maintenance, on‐line harmonic current detection technology for distribution network cables is expected to become an effective supplement to traditional offline diagnostic methods, enhancing the real‐time diagnosis of distribution network cable insulation conditions. This study established a 10 kV distribution network cable test platform and prepared typical defective cables subjected to moisture and long‐term thermal aging. Using COMSOL finite element electromagnetic simulation, the magnetic flux evolution laws of the cable insulation under typical defects were obtained. Experimental tests provided the harmonic current characteristics and statistical features of cables with typical defects. Based on these data, a method for analysing the degradation degree of distribution network cables was constructed using least absolute shrinkage and selection operator (LASSO) regression analysis. Furthermore, a defect‐type identification method based on cluster analysis was proposed. Results indicate that the odd harmonics and the 4th harmonic of the distribution network cable's harmonic current are closely related to the cable's degradation state. A model integrating principal component analysis (PCA) data dimensionality reduction and expectation‐maximization clustering analysis achieved a recognition accuracy of up to 75.64% in distinguishing between moisture‐affected and normal cable states. The proposed on‐line detection and evaluation methods can effectively identify high‐risk cables with latent defects. [ABSTRACT FROM AUTHOR]

Epoxy‐impregnated paper transformer bushings are prone to water absorption due to the presence of water‐attracting moieties in the cellulose chemical structure and epoxy resin, leading to moisture‐induced insulation defects. To understand the mechanism of moisture's impact on epoxy‐impregnated paper, this study developed a testing platform that integrated moisture diffusion, adsorption, and dielectric properties of insulating materials. Insulation specimens made of epoxy resin and epoxy‐impregnated paper were prepared and their water diffusion characteristics were investigated using the Fick diffusion model and the Langmuir model, respectively. The Guggenheim–Anderson–de Boer equation was used to examine the vacuum vapour adsorption characteristics of the materials, providing a theoretical foundation for examining the form of water present within them. The dielectric response of materials with varying moisture levels was then tested to study the effect of water on the dielectric spectrum curve. Using the Extended Derivative Method, the characteristic frequency reflecting the water content of the epoxy‐impregnated paper was extracted. The results demonstrate that 0.01‐Hz characteristic frequency provides superior accuracy for moisture assessment in epoxy resins compared to 50 Hz, and extracting and fitting the relaxation peak characteristic frequency in epoxy‐impregnated paper moisture evaluation yields higher accuracy than using tan δ at the power frequency. [ABSTRACT FROM AUTHOR]

Objectives: This study was designed to investigate the relationship between the morphological structure of condyle and occlusal plane in skeletal Class II malocclusions by imaging measurement. Materials and Methods: This study included 65 skeletal Class II adult patients (18–35 years old) who met the criteria, and all were taken with cone beam computed tomography (CBCT) images (skeletal Class II high angle 38 cases, average angle 18 cases, and low angle nine cases). The statistical methods of mean standard deviation, Pearson correlation, and analysis of variance were used to study the correlation between the size of the condyle and occlusal plane in skeletal Class II malocclusion. Results: The FMA and SN‐OP between the groups in skeletal Class II malocclusion are considered statistically significant, p <.05 high angle group > average angle group > low angle group, whereas there are significant correlations between FMA, FH‐OP, SN‐OP, and the medial–lateral diameter (MLD) of the condyle, p <.05, showing a negative correlation. The anteroposterior diameter of the condyle has no significant correlation with these angles, and the high‐angle group size is smaller than the other groups. Conclusion: In patients with skeletal Class II high angle malocclusion, the MLD and anteroposterior diameters of condyle were smaller than those of average angle and low angle groups, and negatively correlated with the FMA and SN‐OP. That is the steeper occlusal plane, the smaller MLD of the condyle. It suggests whether orthodontists can promote the stability of the morphological structure of the condyle by changing the inclination of the occlusal plane during the orthodontic process. [ABSTRACT FROM AUTHOR]

Scar formation and chronic ulcers can develop following a skin injury. They are the result of the over‐ or underproduction of collagen. It is very important to evaluate the quality and quantity of the collagen that is produced during wound healing, especially with respect to its structure, as these factors are very important to a complicated outcome. However, there is no standard way to quantitatively analyse dermal collagen. As prior work characterised some potentially fractal properties of collagen, it was hypothesised that collagen structure could be evaluated with fractal dimension analysis. Small‐angle X‐ray scattering technology (SAXS) was used to evaluate the dermis of rats exposed to graft harvest, burn, and diabetic pathologic states. It was found that almost all collagen structures could be quantitatively measured with fractal dimension analysis. Further, there were significant differences in the three‐dimensional (3‐D) structure of normal collagen versus that measured in pathologic tissues. There was a significant difference in the 3‐D structure of collagen at different stages of healing. The findings of this work suggest that fractal analysis is a good tool for wound healing analysis, and that quantitative collagen analysis is very useful for assessing the structure of dermal collagen. [ABSTRACT FROM AUTHOR]

Psychophysical experiments were conducted to investigate the impacting factors on the image quality of HDR displays. The results indicate that the OLED display has advantages over IPS and VA LCDs due to its lower minimum luminance level and less pixel interaction, thus being an appropriate choice to display HDR contents. [ABSTRACT FROM AUTHOR]

A new spectral reflectance estimation method based on CIE XYZ values under multi-illuminants was proposed to obtain multi-spectral images accurately by using digital still cameras. CIE XYZ values under multi-illuminants were initially predicted from raw RGB responses by using a polynomial model with local training samples. Then, spectral reflectance was constructed from the predicted CIE XYZ values via the pseudo-inverse method. Experimental results indicated that the new spectral reflectance estimation method significantly outperformed the traditional colorimetric characterization method without requiring extra training samples or greatly increasing computational complexities. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 68-77, 2017 [ABSTRACT FROM AUTHOR]

Adipose-derived stem cells (ASCs) can differentiate into multiple cell lineages and favor adipogenesis rather than osteogenesis. Because the extracellular matrix (ECM) component of the stem cell niche is important in stem cell differentiation, we hypothesized that ECM produced by human bone marrow stromal cells (BM-ECM) could enhance the osteogenic potential of ASCs during in vitro expansion. We have compared the replication and osteogenic differentiation of ASCs expanded on BM-ECM versus tissue culture plastic (TCP) in vitro and in vivo. During the first two passages, ASC proliferation on BM-ECM was 3.27-fold greater than that on TCP. ASCs expanded on BM-ECM formed more osteogenic colonies and higher expression of osteogenic markers than ASCs expanded on TCP. In nude mice, ASCs that had been expanded on BM-ECM formed more new bone tissue than those expanded on TCP. The data indicate that BM-ECM can be used to promote the osteogenic fate of ASCs. [ABSTRACT FROM AUTHOR]

Most of the colour-difference formulae were developed to fit data sets having a limited range of colour-difference magnitudes. Hence, their performances are uncertain when applying them to a range of colour differences from very small to very large colour differences. This article describes an experiment including three parts according to the colour-difference magnitudes: large colour difference (LCD), small colour difference (SCD), and threshold colour difference (TCD) corresponding to mean ΔE [ABSTRACT FROM AUTHOR]

- A psychophysical experiment was carried out to assess the perceptual contrast on a large-sized liquid-crystal display (LCD) under nine phases of viewing conditions. Based on the results, six contrast models employing different color attributes or the index of just-noticeable difference (JND) were developed. Their performances were also tested by the visual data of the nine phases, which indicated that the model CQ employing CIECAM02 brightness gives the best performance in predicting visual data under different viewing conditions among those models. A preprocessing step was also proposed to utilize the contrast model CQ conveniently in the practical contrast evaluation of LCDs. [ABSTRACT FROM AUTHOR]

In this study, the proper luminance of HDR TV system was figured out via psychophysical experiments under different illumination and viewing conditions with a high luminance liquid crystal display. The luminance of 600cd/m2 is recommended as the reference of the highest threshold for HDR TV system to avoid discomfort glare. [ABSTRACT FROM AUTHOR]

The Color Association of China (CAC) is one of the committees of the Chinese Optical Society (COS), specialized for color science and technology. On 12-14 July 2007, the CAC hosted the Midterm Meeting of the International Color Association (AIC 2007), with the theme "Color Science for Industry", in Hangzhou, China. And the 3 SP rd sp International Conference of the Asia Color Association (ACA 2016) was also hosted by the CAC, with the theme "Color Driving Power", on 21-22 May 2016 in Changshu, China. [Extracted from the article]