Synthesis of g-C3N4/CQDs composite and its photocatalytic degradation property for Rhodamine B

Jin Tao,Liu Chengbao,Chen Feng,Qian Junchao,Qiu Yongbin,Meng Xianrong,Chen Zhigang 한국탄소학회 2022 Carbon Letters Vol.32 No.6

To solve the problem of water pollution, researchers have proposed a photocatalytic degradation technology, in which the key factor is the development of efficient photocatalytic materials. Graphitic carbon nitride (g-C3N4), an n-type semiconductor, has been widely studied due to its suitable band gap (2.7 eV), low cost, easy preparation, non-toxicity, and high photostability. However, the pure-phase g-C3N4 still has defects such as low specific surface area, insufficient visible light absorption, low charge mobility, few active sites for interfacial reaction, and easy recombination of photogenerated electron–hole pairs, which leads to the lower photocatalytic activity of g-C3N4. Aiming at the problems mentioned above, this paper focus on the synthesis of g-C3N4-based composites with high photocatalytic activity via lemon juice induction method. Thiourea and lemon juice were selected as precursors, and carbon quantum dots (CQDs) as electron mediators were introduced anchoring on the surface of g-C3N4 to build g-C3N4/CQDs with compact interface. The results showed that small-sized CQDs are uniformly distributed on the surface of g-C3N4, and the g-C3N4/CQDs composite has a 2D0D structure, which reduces the recombination of photogenerated electron–hole pairs. The photocatalytic degradation efficiency of 4% g-C3N4/CQDs for RhB reaches the highest data of 90.9%, and the photocatalytic degradation rate is 0.016 min−1, which is about 2.3 times that of g-C3N4. After four cycles of photocatalytic reaction, the photocatalytic degradation efficiency of the material remained at 81.7%. Therefore, the g-C3N4/CQDs synthesized via lemon juice induction has a more stable microstructure, and the charge separation efficiency is greatly improved, which is suitable for practical photocatalytic environmental protection.

Thioredoxin peroxidase from the bumblebee, Bombus ignitus: cDNA sequence, expression and functional characterization

Zhigang Hu,Kwang Sik Lee,Hyung Joo Yoon,Hung Dae Sohn,Byung Rae Jin 한국응용곤충학회 2008 한국응용곤충학회 학술대회논문집 Vol.2008 No.05

A thioredoxin peroxidase (TPx) gene was cloned from the bumblebee, Bumbus ignitus. The B. ignitus TPx (BiTPx) contains an open reading frame of 585 bp encoding 195 amino acid residues and possesses two cysteine residues that are characteristic of 2-Cys subgroup of peroxiredoxin family. The deduced amino acid sequence of the BiTPx cDNA showed 90% identity to Apis melifera (AmTPx-1), 80% to Aedes aegypti (AaTPx), and 78% - 47% to other insect 2-Cys TPx. Northern blot analysis revealed the presence of BiTPx transcripts in all tissues examined. Western blot analysis showed the presence of the BiTPx in the fat body, midgut, muscle and epidermis, but not in the hemolymph, suggesting the BiTPx is not secretable. The cDNA encoding BiTPx was expressed as a 27-kDa polypeptide in baculovirus-infected insect Sf9 cells. The purified recombinant BiTPx was shown to reduce H2O2 in the presence of electrons donated by dithiothreitol and shown to be active in the presence of thioredoxin as electron donor.

Molecular characterization of a phospholipid-hydroperoxide glutathione peroxidase from the bumblebee Bombus ignitus

Zhigang Hu,Kwang Sik Lee,Young Moo Choo,Yu Xin,Hyung Joo Yoon,Iksoo Kim,Hung Dae Sohn,Byung Rae Jin 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10

Phospholipid-hydroperoxide glutathione peroxide (PHGPx) is an antioxidant enzyme that reduces lipid hydroperoxides in biomembranes. Here, we cloned and characterized cys-PHGPx from the bumblebee Bombus ignitus (Bi-PHGPx). The Bi-PHGPx gene consists of 4 exons, encoding 168 amino acid residues with a canonical cys-codon at residue 45 and active site residues Gln82 and Trp134. Recombinant Bi-PHGPx, expressed as a 19 kDa protein in baculovirus-infected insect cells, exhibited enzymatic activity against PLPC-OOH and H2O2 using glutathione as an electron donor. Tissue distribution analyses showed the presence of Bi-PHGPx in all tissues examined. Bi-PHGPx transcripts were upregulated by stresses, such as wounding, H2O2 exposure, external temperature shock, and starvation. Under H2O2 overload, the RNA interference (RNAi)-induced thioredoxin peroxidase (BiTPx1)-knock-down B. ignitus worker bees showed upregulated expression of Bi-PHGPx in the fat body. These results indicate that Bi-PHGPx is a stress-inducible antioxidant enzyme that acts on phospholipid hydroperoxide and H2O2.

Molecular Cloning and Characterization of a Muscle-Specific Lipase from the Bumblebee Bombus ignitus

Hu, Zhigang,Wang, Dong,Lu, Wei,Cui, Zheng,Jia, Jing-Ming,Yoon, Hyung-Joo,Sohn, Hung-Dae,Kim, Doh-Hoon,Jin, Byung-Rae Korean Society of Sericultural Science 2008 International Journal of Industrial Entomology Vol.17 No.1

A muscle-specific lipase gene of the bumblebee Bombus ignitus was cloned and characterized. This gene, which we named Bi-Lipase, consists of seven exons encoding 317 amino acid residues. Bi-Lipase possesses all the features of lipases, including GXSXG consensus motif and Ser-Asp-His catalytic triad. Expressed as a 37-kDa polypeptide in baculovirus-infected insect Sf9 cells, recombinant Bi-Lipase showed an optimal pH of 9.0 and exhibited its highest catalytic activity at $40^{\circ}C$. Furthermore, through the addition of tunicamycin to the recombinant virus-infected Sf9 cells, recombinant Bi-Lipase was found to be N-glycosylated. Northern and western blot analyses indicated that Bi-Lipase was expressed in the wing, thorax, and leg muscles. These results show that Bi-Lipase is a muscle-specific lipase, suggesting a possible role of Bi-Lipase in the utilization of lipids for muscular activity in B. ignitus.

Molecular Cloning and Characterization of a Lipocalin in the Bumblebee Bombus Ignitus

Hu, Zhigang,Yoon, Hyung-Joo,Sohn, Hung-Dae,Jin, Byung-Rae Korean Society of Sericultural Science 2009 International Journal of Industrial Entomology Vol.19 No.2

We have cloned and characterized a lipocalin from the bumblebee Bombus ignitus (Bi-lipocalin). The Bi-lipocalin gene spans 2284 bp and consists of four exons coding for 270 amino acid residues. Sequence analysis revealed that Bi-lipocalin possesses three structurally conserved regions (SCTs) that characterize lipocalins. Recombinant Bi-lipocalin, expressed as a 37 kDa protein in baculovirus-infected insect cells, was N-glycosylated, indicating that the carbohydrate moieties are necessary for secretion. Tissue distribution analysis revealed ubiquitous expression of Bi-lipocalin in all tissues examined. Bi-lipocalin transcripts were upregulated by stress, such as wounding, $H_2O_2$ exposure, and external temperature shock. These results indicate that Bi-lipocalin is a stress-inducible protein that acts on wounding, $H_2O_2$ overexposure and temperature stimulation.

Relay selection and Optimization algorithm of Power allocation based on Channel Delay for UWSN

YunLi,Zhigang Jin,Xunjun Wang,Zixin Liu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.2

In the light of the characteristics of random change that underwater sensor change by time, space and frequency, select the best relay node to improve communication quality and get the diversity gain. A new optimal relay selection method is proposed in this paper, by considering two indexes synthetically that channel gain and underwater acoustic communication long time delay to select the best relay node. Based on the best relay node and minimization of bit error rate to take optimal power allocation of source node and relay node to realize network error rate’s reduction of 1.81 dB so then improve the overall performance of the network.

Free vibration analysis of continuous bridge under the vehicles

Guo-jin Tan,Wensheng Wang,Yubo Jiao,Zhigang Wei 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.61 No.3

Free vibration analysis for continuous bridge under any number of vehicles is conducted in this paper. Calculation strategy for natural frequency and mode shape is proposed based on Euler-Bernoulli beam theory and numerical assembly method. Firstly, a half-car planar model is adopted; equations of motion and displacement functions for bridge and vehicle are established, respectively. Secondly, the undermined coefficient matrices for wheels, vehicles, intermediate support, left-end support and right-end support are derived. Then, the numerical assembly technique for conventional finite element method is adopted to construct the overall matrix of coefficients for whole system. Finally, natural frequencies and corresponding mode shapes are determined based on iterative method and overall matrix solution. Numerical simulation is presented to verify the effectiveness of the proposed method. The results reveal that the solutions of present method are exact ones. Natural frequencies and associate modal shapes of continuous bridge under different conditions of vehicles are investigated. The influences of vehicle parameters on natural frequencies are also demonstrated.

UMMAC: A Multi-Channel MAC Protocol for Underwater Acoustic Networks

Yishan Su,Zhigang Jin 한국통신학회 2016 Journal of communications and networks Vol.18 No.1

In this paper, we propose a multi-channel medium accesscontrol (MAC) protocol, named underwater multi-channel MACprotocol (UMMAC), for underwater acoustic networks (UANs). UMMAC is a split phase and reservation based multi-channelMAC protocol which enables hosts to utilize multiple channels viaa channel allocation and power control algorithm (CAPC). In UMMAC,channel information of neighboring nodes is gathered viaexchange of control packets. With such information, UMMAC allowsfor as many parallel transmissions as possible while avoidingusing extra time slot for channel negotiation. By running CAPCalgorithm, which aims at maximizing the network’s capacity, userscan allocate their transmission power and channels in a distributedway. The advantages of the proposed protocol are threefold: 1)Only one transceiver is needed for each node; 2) based on CAPC,hosts are coordinated to negotiate the channels and control powerin a distributed way; 3) comparing with existing RTS/CTS MACprotocols, UMMAC do not introduce new overhead for channel negotiation. Simulation results show that UMMAC outperforms Slottedfloor acquisition multiple access (FAMA) and multi-channelMAC (MMAC) in terms of network goodput (50% and 17% respectivelyin a certain scenario). Furthermore, UMMAC can lowerthe end-to-end delay and achieves a lower energy consumptioncompared to Slotted FAMA and MMAC.

UMMAC: A Multi-Channel MAC Protocol for Underwater Acoustic Networks

Su, Yishan,Jin, Zhigang The Korea Institute of Information and Commucation 2016 Journal of communications and networks Vol.18 No.1

In this paper, we propose a multi-channel medium access control (MAC) protocol, named underwater multi-channel MAC protocol (UMMAC), for underwater acoustic networks (UANs). UMMAC is a split phase and reservation based multi-channel MAC protocol which enables hosts to utilize multiple channels via a channel allocation and power control algorithm (CAPC). In UMMAC, channel information of neighboring nodes is gathered via exchange of control packets. With such information, UMMAC allows for as many parallel transmissions as possible while avoiding using extra time slot for channel negotiation. By running CAPC algorithm, which aims at maximizing the network's capacity, users can allocate their transmission power and channels in a distributed way. The advantages of the proposed protocol are threefold: 1) Only one transceiver is needed for each node; 2) based on CAPC, hosts are coordinated to negotiate the channels and control power in a distributed way; 3) comparing with existing RTS/CTS MAC protocols, UMMAC do not introduce new overhead for channel negotiation. Simulation results show that UMMAC outperforms Slotted floor acquisition multiple access (FAMA) and multi-channel MAC (MMAC) in terms of network goodput (50% and 17% respectively in a certain scenario). Furthermore, UMMAC can lower the end-to-end delay and achieves a lower energy consumption compared to Slotted FAMA and MMAC.

Electric-Field-Assisted Assembly of Polymer-Tethered Gold Nanorods in Cylindrical Nanopores

Wang, Ke,Jin, Seon-Mi,Xu, Jiangping,Liang, Ruijing,Shezad, Khurram,Xue, Zhigang,Xie, Xiaolin,Lee, Eunji,Zhu, Jintao American Chemical Society 2016 ACS NANO Vol.10 No.5

<P>In this report, we demonstrate the confined assembly of polymer-tethered gold nanorods in anodic aluminum oxide (AAO) channels with the assistance of electric field (EF). Various interesting hybrid assemblies, such as single-, double-, triple-, or quadruple-helix, linear, and hexagonally packed structures are obtained by adjusting pore size in AAO channels, ligand length, and EF orientation. Correspondingly, surface plasmonic property of the assemblies can thus be tuned. This strategy, by coupling of external-field and cylindrically confined assembly, is believed to be a promising approach for generating ordered hybrid assemblies with hierarchical structures, which may find potential applications in photoelectric devices, biosensors, and data storage devices.</P>