Single Remote-Sensing Image Dehazing in HSI Color Space

Yongfei Guo,Zeshu Zhang,Hangfei Yuan,Shuai Shao 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.8

In order to improve the visibility of a single hazy remote sensing multi-spectral image, we develop a novel and effective dehazing algorithm in HSI (hue, saturation and intensity) color space. First of all, the hazy image is transformed into HSI color space; then a linear regression model is built for saturation component image processing. In addition, we implement the improved dark channel prior method in the intensity channel processing. Compared with the traditional haze removal methods in remote-sensing images, the experimental results demonstrate that the developed algorithm can achieve better visual effect and better color fidelity. Both qualitative evaluations and quantitative assessments indicate that the proposed method achieves a better performance than the state-of-the-art methods.

Optimized Thermoelectric Properties of AgSbTe2 through Adjustment of Fabrication Parameters

Jian Zhang,Xiaoying Qin,Di Li,송천준,Yongfei Liu,Hongxing Xin,Tianhua Zou,Yuanyue Li 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.1

AgSbTe2 bulk sample is obtained by hot-pressing under different fabricationparameters, and their thermoelectric properties are investigated in thetemperature range of 300 - 550 K. The highest ZT = 0.86 is achieved at475 K for the sample hot-pressed at 423 K and 500MPa due to the lowerthermal conductivity and higher power factor. The results indicate that theoptimized thermoelectric properties can be obtained for AgSbTe2 compoundat the sintering temperature of 423 K under the pressure of 500 MPa.

Comparative analysis of metabolites and in vitro hypoglycemic activity of Taiwanofungus camphoratus cultured using various methods

Ming YongFei,Li Yin,Chu JianZhi,Zhou XiaoShuang,Huang YuXuan,Yang ShuDe,Mu YueJun,Wang Lin,Zhang Rui,Cheng XianHao 한국응용생명화학회 2024 Applied Biological Chemistry (Appl Biol Chem) Vol.67 No.-

Taiwanofungus camphoratus has attracted much attention because it can abundantly produce various active substances that exhibit blood-sugar lowering, immunity improving, and antioxidant properties. Currently, T. camphoratus is cultured using four main methods: cutting wood culture, solid-state fermentation, submerged fermentation, and dish culture. T. camphoratus produces different metabolites under different culture methods. In this study, nontargeted metabolomics was used to compare the metabolites of T. camphoratus produced under these four culture methods. Principal component analysis and supervised partial least squares-discriminant analysis were used to analyze the differences in the metabolites. Moreover, in vitro hypoglycemic activity of T. camphoratus extracts produced under four culture methods was compared by assessing their ability to inhibit the activity of α-glucosidase, α-amylase, and sucrase. A total of 186 metabolites were identified. In total, 127 metabolites were common under the four culture methods. Under solid-state fermentation, submerged fermentation, and cutting wood culture, 12, 1, and 4 metabolites were unique, respectively. The differential metabolites produced by T. camphoratus under four culture methods were mainly triterpenoids, phenolic compounds, and fatty acid compounds. α-glucosidase, α-amylase, and sucrase activity inhibition was the best using T. camphoratus extract obtained under cutting wood culture; the inhibition rates were 55.97%, 51.96%, and 78.02%, respectively, which were comparable to those exhibited by 0.001, 3, and 12 mg/mL acarbose (positive control). The metabolites produced by T. camphoratus and α-glucosidase, α-amylase, and sucrase inhibitory activities were different under the four culture methods. Cutting wood culture exhibited the best enzyme inhibitory activity. This study provided a theoretical basis for further use and development of various culture methods for the rational production of active metabolites of T. camphoratus.

Application of Dynamic Regulation to Increase L-Phenylalanine Production in Escherichia coli

( Jie Wu ),( Yongfei Liu ),( Sheng Zhao ),( Jibin Sun ),( Zhaoxia Jin ),( Dawei Zhang ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.6

Current strategies of strain improvement processes are mainly focused on enhancing the synthetic pathways of the products. However, excessive metabolic flux often creates metabolic imbalances, which lead to growth retardation and ultimately limit the yield of the product. To solve this problem, we applied a dynamic regulation strategy to produce L-phenylalanine (LPhe) in Escherichia coli. First, we constructed a series of Phe-induced promoters that exhibited different strengths through modification of the promoter region of tyrP. Then, two engineered promoters were separately introduced into a Phe-producing strain xllp1 to dynamically control the expression level of one pathway enzyme AroK. Batch fermentation results of the strain xllp3 showed that the titer of Phe reached 61.3 g/l at 48 h, representing a titer of 1.36- fold of the strain xllp1 (45.0 g/l). Moreover, the L-Phe yields on glucose of xllp3 (0.22 g/g) were also greatly improved, with an increase of 1.22-fold in comparison with the xllp1 (0.18 g/ g). In summary, we successfully improved the titer of Phe by using dynamic regulation of one key enzyme and this strategy can be applied for improving the performance of strains producing other aromatic amino acids and derived compounds.

Application of Dynamic Regulation to Increase L-Phenylalanine Production in Escherichia coli

Wu, Jie,Liu, Yongfei,Zhao, Sheng,Sun, Jibin,Jin, Zhaoxia,Zhang, Dawei The Korean Society for Microbiology and Biotechnol 2019 Journal of microbiology and biotechnology Vol.29 No.6

Current strategies of strain improvement processes are mainly focused on enhancing the synthetic pathways of the products. However, excessive metabolic flux often creates metabolic imbalances, which lead to growth retardation and ultimately limit the yield of the product. To solve this problem, we applied a dynamic regulation strategy to produce $\text\tiny{L}$-phenylalanine ($\text\tiny{L}$-Phe) in Escherichia coli. First, we constructed a series of Phe-induced promoters that exhibited different strengths through modification of the promoter region of tyrP. Then, two engineered promoters were separately introduced into a Phe-producing strain xllp1 to dynamically control the expression level of one pathway enzyme AroK. Batch fermentation results of the strain xllp3 showed that the titer of Phe reached 61.3 g/l at 48 h, representing a titer of 1.36-fold of the strain xllp1 (45.0 g/l). Moreover, the $\text\tiny{L}$-Phe yields on glucose of xllp3 (0.22 g/g) were also greatly improved, with an increase of 1.22-fold in comparison with the xllp1 (0.18 g/g). In summary, we successfully improved the titer of Phe by using dynamic regulation of one key enzyme and this strategy can be applied for improving the performance of strains producing other aromatic amino acids and derived compounds.

Seismic Fragility Analysis of V-Shaped Continuous Girder Bridges

Leping Ren,Gang Zhang,Yongfei Zhang,Shuanhai He 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.3

This paper presents an improved approach for evaluating seismic performance of V-shaped continuous girder bridges with different V-angles. A 3-D finite element model is established using the OpenSees for tracing the response of a typical three-span V-shaped continuous girder bridge. The analysis is performed in three steps: component fragility analysis, validated system fragility analysis and V-angle analysis. A series of nonlinear time history analysis(NLTHA), considering the uncertainty in bridge structural parameters and ground motions characteristics, is carried out to investigate the potential fragile position of a V-shapedcontinuous girder bridge. Subsequently, a new improved product of conditional marginal(PCM) method is validated successfully and utilized to form the system fragility curves. The application of the validated method is used to analyse the influence of V-angle on the bridge structural system fragility. The analysis result shows that variation of V-angle has significantinfluence on seismic fragility of V-shaped continuous girder bridges. The V-shaped continuous girder bridges with 80° V-angle has good seismic performance when PGA ≤ 0.8 g. Smaller V-angle can result in higher seismic fragility of V-shaped continuous girder bridges.