Improving the Thermal Stability of Polybenzoxazines Through Incorporation of Eugenol-Based Benzoxazine

Yongfei Zhu,Junming Su,Runsheng Lin,Peilin Li 한국고분자학회 2020 Macromolecular Research Vol.28 No.5

To introduce the para-position of phenol or aniline moiety into the crosslinked network of polybenzoxazine and improve its thermal stability, benzoxazine based on eugenol and 4,4’-diaminodiphenylmethane (e-ddm) was copolymerized with bisphenol A-aniline-based benzoxazine (b-a) or phenol-aniline-based benzoxazine (p-a). The differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR) results show that the carbenium ion intermediate from e-ddm could react with the para-position of phenol or aniline in b-a and p-a during the ringopening polymerization process, resulting in that the aniline and phenol moieties were introduced into cross-linked structures of polybenzoxazines. The thermogravimetric analysis (TGA) and TGA interfaced with FTIR results indicate that the thermal stability of polybenzoxazines increased with the incorporation of e-ddm, due to that the volatilization of phenol, aniline and their derivatives was restrained during the thermal degradation processes. Thereby, introducing e-ddm into benzoxazine is a better method of increasing the thermal stability of polybenzoxazine.

Microstructural coarsening of 6061 aluminum alloy semi-solid billets prepared via recrystallization and partial melting

Yongfei Wang,Sheng-Dun Zhao,Xuzhe Zhao,Yongqiang Zhao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

In this study, the Recrystallization and partial melting (RAP) process was performed to prepare 6061 aluminum alloy semi-solid billets. The microstructural evolution and coarsening of the materials were investigated. During the RAP process, the 6061 aluminum alloy plate supplied in cold rolled state was heated to the semi-solid range. The results showed that both the average grain size and shape factor of solid grains increased along with the isothermal holding time and temperature. The coarsening of solid grains could be attributed to the coalescence and Ostwald ripening mechanisms, with the latter playing an increasingly important role as the isothermal holding time and temperature increased. At isothermal holding temperatures of 620, 625, 630 and 635 °C, the coarsening rate constants reached 333.1, 833.8, 1034.7 and 1271.9 µm/s 3 , respectively. Moreover, the coarsening rate constant gradually increased along with isothermal holding temperature.

Intelligent On-demand Routing Protocol for Ad Hoc Network

Yongfei Ye,Xinghua Sun,Minghe Liu,Jing Mi,Ting Yan,Lihua Ding 한국정보처리학회 2020 Journal of information processing systems Vol.16 No.5

Ad hoc networks play an important role in mobile communications, and the performance of nodes has asignificant impact on the choice of communication links. To ensure efficient and secure data forwarding anddelivery, an intelligent routing protocol (IAODV) based on learning method is constructed. Five attributes ofnode energy, rate, credit value, computing power and transmission distance are taken as the basis ofsegmentation. By learning the selected samples and calculating the information gain of each attribute, thedecision tree of routing node is constructed, and the rules of routing node selection are determined. IAODValgorithm realizes the adaptive evaluation and classification of network nodes, so as to determine the optimaltransmission path from the source node to the destination node. The simulation results verify the feasibility,effectiveness and security of IAODV.

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.

Central role of autophagic UVRAG in melanogenesis and the suntan response

Yang, Yongfei,Jang, Gyu-beom,Yang, Xuanjun,Wang, Qiaoxiu,He, Shanshan,Li, Shun,Quach, Christine,Zhao, Shihui,Li, Fan,Yuan, Zengqiang,Lee, Hye-Ra,Zhong, Hanbing,Liang, Chengyu National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.33

<P>UV-induced cell pigmentation represents an important mechanism against skin cancers. Sun-exposed skin secretes alpha-MSH, which induces the lineage-specific transcriptional factor MITF and activates melanogenesis in melanocytes. Here, we show that the autophagic tumor suppressor UVRAG plays an integral role in melanogenesis by interaction with the biogenesis of lysosome-related organelles complex 1 (BLOC-1). This interaction is required for BLOC-1 stability and for BLOC-1-mediated cargo sorting and delivery to melanosomes. Absence of UVRAG dispersed BLOC-1 distribution and activity, resulting in impaired melanogenesis in vitro and defective melanocyte development in zebrafish in vivo. Furthermore, our results establish UVRAG as an important effector for melanocytes' response to alpha-MSH signaling as a direct target of MITF and reveal the molecular basis underlying the association between oncogenic BRAF and compromised UV protection in melanoma.</P>

Supply Chain Coordination Considering Stochastic Demand and Raw Material Quality Defects

Li Yongfei 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.5

This paper solves the coordination strategies of a supplier and a manufacturer separately under the condition of decentralized, centralized and revenue sharing supply chain based on Steinberg non-cooperative game theory. The research presumes: 1)The manufacturer completely inspects materials of supplier; 2) The manufacturer repairs the unqualified products resulting from supplier’s raw material quality defects; 3) the single manufacturer faces a random demand under single period newsboy model. We find out that marginal effect will be enlarged when the manufacturer repairs the unqualified productions. When supply chain is coordinated, EOQ, total profit and total risk-sharing of centralized supply chain are larger than that of non-coordination or decentralized supply chain. The integrated model of revenue sharing supply chain can achieve the performance of centralized supply chain. The establishment of this integration will not be affected by changes in wholesale price of suppliers. Our research can provide some theoretical basis for supply chain to reduce internal and external risk loss costs.

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 . 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.

Research and Implementation of U-Learning System Based on Experience API

Xinghua Sun,Yongfei Ye,Jie Yang,Li Hao,Lihua Ding,Haomin Song 한국정보처리학회 2020 Journal of information processing systems Vol.16 No.3

Experience API provides a learner-centered model for learning data collection and learning process recording. In particular, it can record learning data from multiple data sources. Therefore, Experience API provides verygood support for ubiquitous learning. In this paper, we put forward the architecture of ubiquitous learningsystem and the method of reading the learning record from the ubiquitous learning system. We analyze students’learning behavior from two aspects: horizontal and vertical, and give the analysis results. The system canprovide personalized suggestions for learners according to the results of learning analysis. According to thefeedback from learners, we can see that this u-learning system can greatly improve learning interest and qualityof learners.

Research on the Application of Load Balancing in Educational Administration System

Junrui Han,Yongfei Ye 한국정보처리학회 2023 Journal of information processing systems Vol.19 No.5

Load balancing plays a crucial role in ensuring the stable operation of information management systems duringperiods of high user access requests; therefore, load balancing approaches should be reasonably selected. Moreover, appropriate load balancing techniques could also result in an appropriate allocation of systemresources, improved system service, and economic benefits. Nginx is one of the most widely used loadbalancingsoftware packages, and its deployment is representative of load-balancing application research. Thisstudy introduces Nginx into an educational administration system, builds a server cluster, and compares andsets the optimal cluster working strategy based on the characteristics of the system, Furthermore, it increasesthe stability of the system when user access is highly concurrent and uses the Nginx reverse proxy servicefunction to improve the cluster’s ability to resist illegal attacks. Finally, through concurrent access verification,the system cluster construction becomes stable and reliable, which significantly improves the performance ofthe information system service. This research could inform the selection and application of load-balancingsoftware in information system services.

A Distributed Privacy-Utility Tradeoff Method Using Distributed Lossy Source Coding with Side Information

( Yonghao Gu ),( Yongfei Wang ),( Zhen Yang ),( Yimu Gao ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.5

In the age of big data, distributed data providers need to ensure the privacy, while data analysts need to mine the value of data. Therefore, how to find the privacy-utility tradeoff has become a research hotspot. Besides, the adversary may have the background knowledge of the data source. Therefore, it is significant to solve the privacy-utility tradeoff problem in the distributed environment with side information. This paper proposes a distributed privacy-utility tradeoff method using distributed lossy source coding with side information, and quantitatively gives the privacy-utility tradeoff region and Rate-Distortion-Leakage region. Four results are shown in the simulation analysis. The first result is that both the source rate and the privacy leakage decrease with the increase of source distortion. The second result is that the finer relevance between the public data and private data of source, the finer perturbation of source needed to get the same privacy protection. The third result is that the greater the variance of the data source, the slighter distortion is chosen to ensure more data utility. The fourth result is that under the same privacy restriction, the slighter the variance of the side information, the less distortion of data source is chosen to ensure more data utility. Finally, the provided method is compared with current ones from five aspects to show the advantage of our method.