Flow-Net : A Proposal on ABR Traffic Control in ATM Networks

Wenfeng Chen,H. T. Mouftah 한국통신학회 1995 Asia-Pacific Conference on Communications Vol.2 No.1

Recent Development of Laboratory-made Solid-phase Microextraction Fibers on the Application of Food Safety Analysis

Jingbin Zeng,Jinmei Chen,Wenfeng Chen,Xiaoli Huang,Liangbi Chen,Xi Chen 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3

Solid-phase microextraction (SPME) has gained widespread acceptance in sample pretreatment due to its solventfree and easy-to-operate properties. SPME fibers are considered as a key part of SPME technique, since it primarily determines the extraction performance of the method including sensitivity, selectivity, and reproducibility. Generally speaking, target analyte with different chemical property requires fiber coating that has the best affinity towards it. Due to the lack of varieties of commercial fibers available currently, considerable efforts have been recently made to develop tailor-made fibers to fulfill increasing demands of different analysis. This paper concisely classify some SPME fiber preparation approaches such as solgel technology, physical deposition, molecularly imprinted technique, and their respective application in food safety analysis.

Bacterial Community Structure and Function Shift in Rhizosphere Soil of Tobacco Plants Infected by Meloidogyne incognita

Wenjie Tong(Wenjie Tong),Junying Li(Junying Li),Wenfeng Cong(Wenfeng Cong),Cuiping Zhang(Cuiping Zhang),Zhaoli Xu(Zhaoli Xu),Xiaolong Chen(Xiaolong Chen),Min Yang(Min Yang),Jiani Liu(Jiani Liu),Lei Yu 한국식물병리학회 2022 Plant Pathology Journal Vol.38 No.6

Root-knot nematode disease is a widespread and catastrophic disease of tobacco. However, little is known about the relationship between rhizosphere bacterial community and root-knot nematode disease. This study used 16S rRNA gene sequencing and PICRUSt to assess bacterial community structure and function changes in rhizosphere soil from Meloidogyne incognita-infected tobacco plants. We studied the rhizosphere bacterial community structure of M. incognita-infected and uninfected tobacco plants through a paired comparison design in two regions of tobacco planting area, Yuxi and Jiuxiang of Yunnan Province, southwest China. According to the findings, M. incognita infection can alter the bacterial population in the soil. Uninfested soil has more operational taxonomic unit numbers and richness than infested soil. Principal Coordinate Analysis revealed clear separations between bacterial communities from infested and uninfested soil, indicating that different infection conditions resulted in significantly different bacterial community structures in soils. Firmicutes was prevalent in infested soil, but Chloroflexi and Acidobacteria were prevalent in uninfested soil. Sphingomonas, Streptomyces, and Bradyrhizobium were the dominant bacteria genera, and their abundance were higher in infested soil. By PICRUSt analysis, some metabolism-related functions and signal transduction functions of the rhizosphere bacterial community in the M. incognita infection-tobacco plants had a higher relative abundance than those uninfected. As a result, rhizosphere soils from tobacco plants infected with M. incognita showed considerable bacterial community structure and function alterations.

Electrochemical synthesis and properties of multicolor electrochromic triphenylamine-based polymer films

Xiuhong Chen,Panxu Tang,Hong Yu,Wenfeng Xu,Xiaojia Zhao 한국고분자학회 2024 Macromolecular Research Vol.32 No.6

Four novel triphenylamine-based (TPA-based) conjugate polymer films (one homopolymer and three co-polymers) were electrochemically synthesized from N4,N4′-bis(4-((6-(1H-indol-1-yl)hexyl)oxy)phenyl)-N4,N4′-diphenyl-[1,1′-biphenyl]- 4,4′-diamine (TPY) and 3,4-ethylenedioxythiophene (EDOT) as monomers. The polymer structure was tuned by adjusting the monomer proportions. The homopolymer contains electrochromic TPA and indole groups in its backbone, while an additional electrochromic EDOT groups are present in the co-polymers. The electrochemical, optical, and electrochromic properties of the polymers were characterized along with film morphologies. Each polymer is multicolored, with electrochromic performance that depends heavily on its structure. The introduction of EDOT into the backbone significantly improved polymer-film-forming properties. In addition, the co-polymers exhibited excellent spectroelectrochemical performance and are visible–near-infrared electrochromic materials. In particular, the spectrum of oxidized PTPY–EDOT-2 covers the entire visible region, while oxidized PTPY–EDOT-3, which contains the highest amount of EDOT, strongly absorbs in the nearinfrared region (> 800 nm) while absorbing fully across the visible region. Consequently, PTPY–EDOT-3 is a potential candidate for display and camouflage applications owing to its excellent properties. Double-layer electrochromic devices (ECDs) were fabricated using polymer films and WO3 as active layers. The homo- and co-polymers exhibit particularly different electrochromic performance. The PTPY ECD performs best. It exhibited a maximum contrast of 36.7% at 720 nm in the absence of EDOT, with a coloration efficiency of 418 cm2/ C recorded; moreover, it exhibited an obvious memory effect, with a memory time of 20 min recorded at 480 nm. Consequently, these polymers are potentially useful for optoelectronics applications.

EFFECT OF METHANOL ADDITION ON COMBUSTION AND EMISSIONS CHARACTERISTICS ON A TURBOCHARGED GDI ENGINE

Hong Chen,Jiakun Du,Yuhuai Li,Wenfeng Zhan,Jian Wu,Fangxi Xie,Guangquan Wu 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.5

To enrich the knowledge and understanding of the application effect of methanol fuel in the current engine, the influence of methanol-gasoline blended fuel containing 10 %, 20 % and 30 % methanol addition (M10, M20 and M30) on the engine performance, combustion and emissions were studied on a turbocharged and direct injection engine with original control system and control parameters. The results showed that at the conditions with low speed, the peak heat release rate and cylinder pressure were decreased by the use of blended fuel while it shown an increased peak combustion pressure and heat release rate at high speed. Meanwhile, the combustion center of blended fuel was obviously different from gasoline and its optimal value, and the combustion variation was increased at low load. The fuel consumption lifted continuously with the increase of methanol addition ratio, and the equivalent fuel consumption of M10 and M20 also was higher than that of pure gasoline. For NOx emissions, although it has been improved continuously for M10, M20 and M30 under the higher engine load, the higher emissions were obtained for M10 and M20 at lower load. In addition, compared with gasoline fuel, the whole particle distribution curve and number concentration was significantly deteriorated with methanol addition.

Efficient Visual Place Recognition by Adaptive CNN Landmark Matching

( Yutian Chen ),( Wenyan Gan ),( Yi Zhu ),( Hui Tian ),( Cong Wang ),( Wenfeng Ma ),( Yunbo Li ),( Dong Wang ),( Jixian He ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.11

Visual place recognition (VPR) is a fundamental yet challenging task of mobile robot navigation and localization. The existing VPR methods are usually based on some pairwise similarity of image descriptors, so they are sensitive to visual appearance change and also computationally expensive. This paper proposes a simple yet effective four-step method that achieves adaptive convolutional neural network (CNN) landmark matching for VPR. First, based on the features extracted from existing CNN models, the regions with higher significance scores are selected as landmarks. Then, according to the coordinate positions of potential landmarks, landmark matching is improved by removing mismatched landmark pairs. Finally, considering the significance scores obtained in the first step, robust image retrieval is performed based on adaptive landmark matching, and it gives more weight to the landmark matching pairs with higher significance scores. To verify the efficiency and robustness of the proposed method, evaluations are conducted on standard benchmark datasets. The experimental results indicate that the proposed method reduces the feature representation space of place images by more than 75% with negligible loss in recognition precision. Also, it achieves a fast matching speed in similarity calculation, satisfying the real-time requirement.

Effects of Components on the Photoelectric Properties of CuxO Nanotubes Fabricated by Using Thermal Oxidation of Copper Nanowires

Shaohua Chen,Xuan Liu,Shengyang Dai,Wenfeng Xiang,Haizhong Guo,Junjian Li 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.2

CuxO (Cupric Oxide) nanotubes (NTs) were synthesized by using thermal oxidation of Cu nanowires (NWs) for 2 and 4 hours, respectively, and the effect of the components on their photoelectrical properties due to the infrared (IR) light with a wavelength of 1064 nm were investigated. In the 2-h CuxO NTs, the main component was Cu2O; however, the 4-h CuxO NTs were composed of a mixture of CuO and Cu2O. The photoelectric properties showed that the voltage difference and the sensitivity of 4-h CuxO NTs were more than 3 times those of the 2-h CuxO NTs, and its linear range was only about one-third that of the 2-h CuxO NTs. The above results were caused by the 4-h CuxO NTs containing a higher content of CuO, which had a suitable bandgap of 1.2 eV for light with a wavelength of 1064 nm. In addition, the response and the recovery times for the 4-h NTs were on the same order as those of the 2-h NTs. The conclusions from this article indicated that 4-h and 2-h NTs were very promising for the design of IR photodetector device with higher sensitivity and a larger detection range respectively.

Influence of thermophilic microorganism on non-volatile metabolites during high-temperature pile-fermentation of Chinese dark tea based on metabolomic analysis

Wen Zhu,Wenfeng Wang,Wencan Xu,Shuang Wu,Wenjun Chen,Youyi Huang,Shengpeng Wang 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.7

Pile-fermentation is a critical procedure for producing Chinese dark tea, during which thermophilic microorganisms would play an irreplaceable role. However, there have been little researches on the influences of thermophilic microorganism pile-fermentation (TMPF) in high-temperature of Chinese dark tea. Thus, we conducted high-performance liquid chromatography and nontargeted metabolomic to analyze the non-volatile metabolites of TMPF. Our results discovered that the amounts of ( −)-epigallocatechin gallate, ( −)-epigallocatechin, ( −)-epicatechin gallate, and ( −)-epicatechin were decreased significantly (p < 0.05) after TMPF. By using nontargeted metabolomic analysis, a total of 1733 ion features were detected. KEGG pathway enrichment analysis showed that TMPF had a significant impact on caffeine metabolism. Also, theophylline, 3-methylxanthine, and 1,3,7-trimethyluric acid were increased significantly after TMPF, which suggested that demethylation and oxidation reaction might be the main pathways of caffeine metabolism. This study provides a better understanding of the mechanism of TMPF during high-temperature for Chinese dark tea and lays a foundation for further research.

Back-channel-etched InGaZnO thin-film transistors with Au nanoparticles on the back channel surface

Peng Xiao,Wenfeng Wang,Yingyi Ye,Ting Dong,Shengjin Yuan,Jiaxing Deng,Li Zhang,Jianwen Chen,Jian Yuan 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.2

In this paper, Au nanoparticles (NPs) were introduced on the surface of oxide thin fi lm to enhance the etching resistance of thethin fi lm, and back-channel-etched (BCE) InGaZnO (IGZO) thin fi lm transistors (TFTs) with Au NPs on the back channel surfacewere successfully fabricated. Detailed studies showed that the etching resistance of IGZO thin fi lms was enhanced signifi cantly byintroducing Au NPs on IGZO thin fi lms, and the etching resistance was enhanced with the increase of Au NPs thickness. Furthermore,Au NPs deposited by vaccum evaporation were uniformly dispersed on the IGZO surface other than forming a continuousthin fi lm. By introducing the Au NPs on the IGZO surface, we successfully patterned the S/D electrodes on Au NPs/IGZO andfabricated BCE TFTs. The IGZO-TFTs with 5-nm-thick Au NPs on the back channel surface exhibited excellent electrical characteristicwith a μ sat of 9.9 cm 2 /V s, a SS of 0.26 V/decade, a V on of 0.23 V, an I on/off of 10 6 and an off -state current of 10 −11 A. Inaddition, the introduction of Au NPs did not lead to an increase in the off -state current, which was mainly ascribed to the Schottkybarrier between Au NPs and IGZO due to the high work function of Au. It is a universal method to fabricate BCE TFTs with highelectrical performance, because it was not limited to the types of oxide materials and had no special requirements for equipment.

POTENTIALS OF AIR-EGR DILUTION FOR IMPROVING PERFORMANCE OF A HIGH COMPRESSION RATIO SPARK-IGNITION ENGINE FUELED WITH METHANOL

Lai Kaichang,Chen Hong,Du Jiakun,Zhan Wenfeng,Li Yuhuai,Xie Fangxi 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.4

The effects of air and exhaust gas recirculation (EGR) dilution of a spark ignition engine fueled with methanol under different loads were studied by experiment in this paper. Such as ignition delay, combustion center (CA50), IMEP, break thermal efficiency (BTE) and other parameters were investigated to assess the combustion performance. And discussed in depth the balance between NOx emissions and economic performance represented by brake specific fuel consumption (BSFC). The results showed that combustion progress such as ignition delay, combustion duration and CA50 were more sensitive on the changes of EGR, introducing EGR under the same dilution rate prolonged combustion process. Air-EGR dilution showed the best improvement of IMEP and break thermal efficiency, except the optimal area, increasing EGR rate will decreased IMEP and BTE. Air-EGR dilution strategy showed the best improvement on BSFC than air dilution than EGR dilution. Under light load and high load, when the lowest BSFC was obtained, NOx emissions were less than 0.5 g/kWh with air-EGR dilution strategy.