Investigation of an STATCOM-based Energy Stored Quasi-Z Source Cascaded H-bridgeInverter Photovoltaic Power System

Weihua Liang,Yitao Liu,Shiqi Jiang,Jianchun Peng,Hui Jiang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The energy stored quasi-Z source cascaded Hbridge (ES-qZS-CHB) inverter is widely used in photovoltaic (PV) power generation system because of its unique advantages. However, the existing researches on ESqZS-CHB inverter PV power system mainly focus on the transmission of active power, but pay little attention to reactive power, causing the ES-qZS-CHB inverter PV power system cannot compensate reactive power or improve system performance. This paper proposes a PV power generation and static synchronous compensator based ESqZS-CHB inverter system, to implement the PV generation and reactive power compensation at the same time. Simulation and experimental results verify the system’s excellent performance.

Repetitive Pulsed High Voltage Generation Using Inductive Energy Storage with Static-induction Thyristor as Opening Switch

Weihua Jiang,Nakahiro, K.,Yatsui, K.,Jong-Hyun Kim,Shimizu, N. IEEE 2007 IEEE transactions on dielectrics and electrical in Vol.14 No.4

<P>A compact pulsed high-voltage generator has been developed for applications in pulsed gas discharges. Its operation principle is based on inductive energy storage and it uses a static induction thyristor as the opening switch. It is capable of generating pulsed high voltage of ~15 kV with pulse width of ~200 ns for load resistance of 1 kOmega. This generator can be operated at repetition rate as high as 50 kHz if it is driven directly by 200 V power supply and is cooled by transformer oil. It can also be driven by a 12 V car battery through a chopper circuit, while operating at repetition rate of 2 kHz. In this case, an overall energy efficiency of ~40 % has been obtained.</P>

Reusable, magnetic laser-induced graphene for efficient removal of organic pollutants from water

Jiang Ye,Wan Sijie,Zhao Weiwei,Yu Wenjie,Wang Shuaipeng,Yu Zeqi,Yang Qiu,Zhou Weihua,Liu Xiaoqing 한국탄소학회 2022 Carbon Letters Vol.32 No.4

The hybridization of graphene with magnetic nanoparticles has endowed graphene with increasing interest as the adsorbent for wastewater treatment. However, its fabrication often involves a multi-stepped chemical synthesis process. In this work, we demonstrate a facile, one-step, and solvent-free approach to fabricate Fe3O4 nanoparticle-anchored Laser-Induced Graphene (Fe3O4@LIG) as an efficient adsorbent by direct laser irradiation on a ferric acetylacetonate containing polybenzoxazine film. Raman and X-ray diffraction analysis confirm the graphene component in the adsorbent, and the morphology characterizations show that Fe3O4 nanoparticles are distributed uniformly on LIG with hierarchical meso- and macro-porous structures. Adsorption experiments indicate that Fe3O4@LIG can adsorb methylene blue (MB) from aqueous solutions in a fast and effective manner, with a maximum adsorption capacity up to 350.9 mg/g. The adsorption kinetics and isotherms are also investigated, which are well-described by the pseudo-second-order model and Langmuir model, respectively. Additionally, Fe3O4@LIG is also demonstrated with the efficient removal of a variety of organic solvents from water. The favorable adsorption behavior of Fe3O4@LIG is attributed to its unique porous structure and the molecular interactions with adsorbates. On the other hand, Fe3O4@LIG has high magnetic property, and therefore, it could be easily recovered from water and well regenerated for repeated use. With the efficient adsorption of organic pollutants, magnetic separability, and good recyclability, it is believed that the easy-fabricated Fe3O4@LIG has great potential applications in wastewater treatment.

Community Detection using Closeness Similarity based on Common Neighbor Node Clustering Entropy

Wanchang Jiang,Xiaoxi Zhang,Weihua Zhu 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.8

In order to efficiently detect community structure in complex networks, community detection algorithms can be designed from the perspective of node similarity. However, the appropriate parameters should be chosen to achieve community division, furthermore, these existing algorithms based on the similarity of common neighbors have low discrimination between node pairs. To solve the above problems, a noval community detection algorithm using closeness similarity based on common neighbor node clustering entropy is proposed, shorted as CSCDA. Firstly, to improve detection accuracy, common neighbors and clustering coefficient are combined in the form of entropy, then a new closeness similarity measure is proposed. Through the designed similarity measure, the closeness similar node set of each node can be further accurately identified. Secondly, to reduce the randomness of the community detection result, based on the closeness similar node set, the node leadership is used to determine the most closeness similar first-order neighbor node for merging to create the initial communities. Thirdly, for the difficult problem of parameter selection in existing algorithms, the merging of two levels is used to iteratively detect the final communities with the idea of modularity optimization. Finally, experiments show that the normalized mutual information values are increased by an average of 8.06% and 5.94% on two scales of synthetic networks and real-world networks with real communities, and modularity is increased by an average of 0.80% on the real-world networks without real communities.

Electrophysiological and behavioral responses of Asian and European honeybees to pear flower volatiles

Ma Weihua,Long Denglong,Wang Yi,Li Xinyu,Huang Jiaxing,Shen Jinshan,Su Wenting,Jiang Yusuo,Li Jie 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

Honeybee pollination behavior is influenced by flower volatiles, which honeybees sense via olfactory receptors. Honeybees are only weakly attracted to pear flowers. To investigate the potential reasons, we extracted and determined the floral volatile compounds from three pear cultivars (Su, Ya, and Xuehua) using headspace solidphase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC–MS). The effects of pear flower volatiles on the Asian honeybee (Apis cerana cerana Fabricius) and the European honeybee (Apis mellifera ligustica Spinola) were determined by electroantennogram (EAG) assays and behavioral tests in a three-arm olfactometer. Among the 76 flower volatiles detected with GC–MS, 21 were found in all three pear cultivars, accounting for approximately 70% of the total volatile content. 3-Methyl-1-butanol and (+)-limonene volatiles had the highest relative content. Five compounds elicited strong EAG responses in both bee species: 2-methylbu tyraldehyde, 1-nonanal, 6-methyl-5-hepten-2-one, 3-methyl-1-butanol, and (+)-limonene. Neither bee species showed positive taxis to these volatiles. In behavioral tests, A. mellifera ligustica showed a low preference for 6-methyl-5-hepten-2-one (20%, 400 µg/µL) and 2-phenethyl alcohol (16.7%, 400 µg/µL). Apis cerana cerana showed a low preference for 6-methyl-5-hepten-2-one (6.7%, 400 µg/µL) and 1-nonanal (10%, 400 µg/µL), whereas its preferences for 3-methyl-1-butanol (43.3%, 400 µg/µL) and α-farnesene (40%, 400 µg/µL) were similar to that for the control. Therefore, a lack of attractive volatile compounds could explain why honeybees are only weakly attracted to pear flowers. Therefore, to achieve acceptable pollination in pear orchards, we suggest using flower-scent sugar syrup feeding and a saturation pollination strategy.

A self-powered β-Ga2O3/CsCu2I3 heterojunction photodiode responding to deep ultraviolet irradiation

Gao Ang,Jiang Weiyu,Ma Guoliang,Liu Zeng,Li Shan,Yan Zuyong,Sun Weiming,Zhang Shaohui,Tang Weihua 한국물리학회 2022 Current Applied Physics Vol.33 No.-

In this paper, a lead-free halide perovskite CsCu2I3 film with high stability was prepared by the anti-solvent assisted crystallization method. Then, we coupled it with Ga2O3 to prepare a corresponding heterojunction deep ultraviolet (UV) photodetector. After testing, we concluded that the photodetector is sensitive to 254 nm UV light. The photodetector has good reproducibility, and has an ultra-high photo-to-dark current ratio (PDCR) of more than 105. In addition, under a bias of 10 V and an illuminated intensity of 200 μW/cm2, the responsivity (R) and specific detectivity (D*) reached 20 mA/W and 107 cm Hz1/2 W 1 (Jones), and the external quantum efficiency (EQE) is 10%. Meanwhile, the prepared photodetector could operate at zero bias, i.e., self-powered operation, along with a photocurrent of about 1 nA under illumination with UV light intensity of 200 μW/cm2.

Refined composite multiscale fuzzy entropy: Localized defect detection of rolling element bearing

Yongjian Li,Bingrong Miao,Weihua Zhang,Peng Chen,Jihua Liu,Xiaoliang Jiang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

We proposed an appealing method based on refined composite multiscale fuzzy entropy (RCMFE), infinite feature selection (Inf-FS) algorithm, and support vector machine (SVM) for implementing localized defect detection to keep the downtime and extended damage caused by incipient failure of bearing at a minimum. As a useful approach, multiscale fuzzy entropy (MFE) was utilized to measure the complexity and dynamic changes of signals. However, an inaccurate entropy value would be yielded with the increase of scale factor. Here, as an improvement version of MFE, the RCMFE was proposed to address the shortcomings in the case of short time series. For this novel method, we conducted a full investigation of the effects and robustness by comparing the proposed method with two other entropybased approaches using synthetic signals and real data. Results indicate that the proposed algorithm outperforms the other approaches in terms of reliability and stability. The RCMFE values of bearing signals from one healthy condition and seven fault states are calculated as diagnostic information. Moreover, an intelligent fault identification method was constructed by combining the Inf-FS algorithm and SVM classifier. Experimental results show the usefulness of the proposed strategy.

Calculation of Vibrational Relaxation Times in Multi-component Excitable Gases

Ke-Sheng Zhang,Weihua Ou,Xueqin Jiang,Fei Long,Mingzhe Hu 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.7

In the research field of acoustic propagation in excitable gases, one of the most critical parametersis the vibrational relaxation time, which determines the frequency of the acoustic dispersion stepor the absorption maximum. In this paper, the vibrational relaxation equations given by Tanczos[J. Chem. Phys. 25, 439 (1956)] have been applied to calculate the vibrational multi-relaxationtimes in multi-component gases. The eigenvalues of the energy-transition-rate matrix are provento be the reciprocals of the multi-relaxation times. Comparisons demonstrate that our relaxationfrequencies calculated for various gas compositions, including carbon dioxide, methane, chlorine,nitrogen, and oxygen, agree with the experimental data.

Estimation of Lipoprotein-lipase Activity (LPL) and Other Biochemical Changes in Two Breeds of Overfeeding Geese

Xu, Hengyong,Wang, Yan,Han, Chunchun,Jiang, Li,Zhuo, Weihua,Ye, Jianqiang,Wang, Jiwen Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.9

This study aimed to examine the effect of overfeeding on biochemical parameters and lipoprotein-lipase (LPL) mRNA expression in different tissues associated with hepatic lipogenesis in Sichuan white and Landes geese. Fifty healthy male Sichuan white geese and fifty male Landes geese (Cygnus atratus) were hatched on the same day under the same feeding conditions and were selected as experimental animals. After overfeeding for 14 days (from 14 weeks to 16 weeks) and then slaughtering, the biochemical changes of hepatic lipogenesis were evaluated. Results showed that i) in Landes geese, the plasma concentration of glucose was higher (p<0.001), while plasma concentrations of insulin and VLDL were both lower (p<0.01); ii) the LPL mRNA level in pectoralis muscle and leg muscle of the overfed groups in both breeds was higher (p<0.05) than in the control groups; iii) in Sichuan white geese, the proportion of fatty liver weight was positively correlated with plasma triacylglycerols (TG)(p<0.05) and VLDL concentrations (p<0.05), while these correlations were not significant in Landes geese; and iv) the activity of LPL had significant positive correlation with the proportions of lipids in subcutaneous adipose tissue and abdominal adipose tissue in Sichuan white geese, while in Landes geese the correlation was negative (p<0.05) with proportions of lipids in the liver, LPL activity had a significant positive correlation with the proportions of lipids in subcutaneous adipose tissue. These results suggest that the Landes geese have a better ability to use the massive amount of ingested food and to store lipids preferentially in the liver, but the Sichuan white geese have a relatively lower ability to use energetic nutrients and lipid storage is more efficient in the adipose tissues.

In Vitro Effects of SB202190 on Echinococcus granulosus

Hailong Lv,Siyuan Li,Jing Zhang,Weihua Liang,Xiaoling Mu,Yufeng Jiang 대한기생충학열대의학회 2013 The Korean Journal of Parasitology Vol.51 No.2

Spillage of cyst contents during surgical operation is the major cause of recurrence after hydatid cyst surgery. Instillation of a scolicidal agent into a hepatic hydatid cyst is the most commonly employed measure to prevent this complication. SB202190 is a pyridinyl imidazole derivative and is known to be a specific inhibitor of p38 MAPK. In the present study, the scolicidal effect of SB202190 was investigated. Freshly isolated Echinococcus granulosus protoscolices were subjected to SB202190 treatment (10, 20, 40, and 80 μM), and the effects on parasite viability were monitored by trypan blue staining. Corresponding effects were visualized by scanning and transmission electron microscopy. Dose-dependent protoscolex death within a few days of SB202190 treatment was observed. Although the in vitro scolicidal effect of SB202190 was satisfactory, the in vivo efficacy of this drug and also possible side effects remain to be further investigated.