Cuprum Metal-Organic-Framework and Polyacrylonitrile-Derived Cu-N-C Electrocatalyst for Application in Zinc-Air Batteries

Yajun Zhao,Jintao Chen,Xiaorui Li,Jiaqing Zhang,Yanan Li,Yajun Zhao,Liye Cao,Xiaoshi Jin 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2020 NANO Vol.15 No.02

Cu-N-C electrocatalyst was successfully prepared with Cu-BTC and polyacrylonitrile as templates by electrospinning and in-situ growth method. The effect of various N-doped content on the electrochemical performance of the catalyst were investigated and the Cu-N-C-0.25 exhibited the best OER/ORRcatalytic activities. When it was applied to the cathode of the zinc-air batteries, the power density of Cu-N-C-0.25 was 209.1 mW cm -2, which exceeded that of the commercial Pt/C + IrO2 hybrid catalyst (157 mW cm -2). The excellent electrochemical performance may be attributed to large number of active sites and high specific surface area on Cu-N-C electrocatalyst. It will be a promising alternative to precious metal catalysts containing Pt, Ir or Ru and their oxides.

Simulation of Nonstationary Process Using Ensemble Empirical Mode Decomposition and Empirical Envelope Methods

Yajun Zhao,Yuanming Dou 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.11

A simulation method for nonstationary process is proposed based on the ensemble empirical mode decomposition (EEMD) and the empirical envelope (EE) methods: the EEMD is used to decompose a nonstationary process into several mono-component signals, and then the EE method is utilized to calculate the instantaneous characteristics of these mono-component signals; a simulated process can be constructed based on the distributions of the instantaneous characteristics of the mono-component signals. An earthquake ground motion recorded in chi-chi earthquake and a nonstationary wind speed induced by typhoon Rammasun are utilized to verify the accuracy and efficacy of the newly-developed method. Results show that: the EE method performs much better than the Hilbert transform (HT)-based method in calculating the instantaneous frequency; the proposed method can successfully capture the global and transient energy distributions of a nonstationary process; the nonstationary wind speed can be modeled as a uniformly modulated nonstationary process, while the earthquake ground motion should be modeled as a non-uniformly modulated nonstationary process. The proposed method does not include any pre-assumed modulation function or inappropriate assumption such as piece-wise stationarity. The method is applicable to the simulation of various types of nonstationary processes, and it can be extended to simulate multivariate nonstationary processes.

Bacterial Community Shift during the Startup of a Full-Scale Oxidation Ditch Treating Sewage

( Yajun Chen ),( Lin Ye ),( Fuzheng Zhao ),( Lin Xiao ),( Shupei Cheng ),( Xu-xiang Zhang ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.1

The oxidation ditch (OD) is one of the most widely used processes for treating municipal wastewater. However, the microbial communities in the OD systems have not been well characterized, and little information about the shift of bacterial community during the startup process of the OD systems is available. In this study, we investigated the bacterial community changes during the startup period (over 100 days) of a full-scale OD. The results showed that the bacterial community dramatically changed during the startup period. Similar to the activated sludge samples in other studies, Proteobacteria (accounting for 26.3%-48.4%) was the most dominant bacterial phylum in the OD system, but its relative abundance declined nearly 40% during the startup process. It was also found that Planctomycetes proliferated greatly (from 4.79% to 13.5%) and finally replaced Bacteroidetes as the second abundant phylum in the OD system. Specifically, some bacteria affiliated with genus Flavobacterium exhibited remarkable decreasing trends, whereas bacterial species belonging to the OD1 candidate division and Saprospiraceae family were found to increase during the startup process. Despite of the bacterial community shift, the organic matter, nitrogen, and phosphorus in the effluent were always in low concentrations, suggesting the functional redundancy of the bacterial community. Moreover, by comparing with the bacterial community in other municipal wastewater treatment bioreactors, some potentially novel bacterial species were found to be present in the OD system. Collectively, this study improved our understandings of the bacterial community structure and microbial ecology during the startup of a full-scale wastewater treatment bioreactor.

The protection of Rhein lysinate to liver in diabetic mice induced by high-fat diet and streptozotocin

Yajun Lin,Gang Hu,Kai-Ji Li,Yu-Fang Zhao,Jie Wei,Yongzhan Zhen 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.5

Rhein lysinate (RHL) is the salt of lysine andrhein and the objective of this study was to investigate theprotection of RHL to liver in diabetic mice. The model oftype 2 diabetes was established by high-fat diet andstreptozotocin treatment. Malondialdehyde, superoxidedismutase (SOD) and glutathione peroxidase (GSH-Px)were measured using a spectrophotometer. Inflammatoryfactors (TNF-a and IL-6) and related proteins (ERK1/2 andSREBP-1c) were analyzed by Western blot. Tissue profilewas determined by hematoxylin and eosin staining andaccumulation of fat was examined by Nile red staining. The results indicated that plasma glucose levels of type 2diabetic mice were over 13.9 mM. Compared with modelgroup, plasma glucose levels were decreased, howeverinsulin levels were increased in RHL (25 and 50 mg/kg)-treated group. Elevated plasma triglyceride and cholesterolwere also markedly attenuated after RHL treatment. Theactivities of SOD and GSH-Px of livers were increasedafter RHL treatment. Livers of RHL-treated mice had morenormal structure and less steatosis than that of diabeticmice. Moreover, RHL decreased the expression of TNF-aand IL-6 and the phosphorylation of SREBP-1c and ERK1/2. In conclusion, RHL has a noticeable hepatic protectionin diabetic mice.

Supplement of High Protein-Enriched Diet Modulates the Diversity of Gut Microbiota in WT or PD-1H-Depleted Mice

( Yajun Xie ),( Ping Zhao ),( Zhigang Han ),( Wei Li ),( Dan Shi ),( Lei Xu ),( Qiying Yi ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.2

Supplement of high-protein food plays an important role in improving the symptoms of malnutrition and the immune capacity of the body, but the association of high-protein diet and gut microbiota remained unaddressed. Here, we systematically analyzed the internal organs and gut microbiota in C57(WT) or PD-1H-depleted (KO) mice (T cells were activated) fed with pupae or feed for six weeks. We observed that the body weight gain in the mice fed with pupae increased less significantly than that of the feed group, while the villi and small intestine lengths in the pupa group were reduced compared with that of mice given feed. However, the average body weight of the KO mice increased compared with that of the WT mice fed with pupae or feed. Pupae increased the concentration of blood glucose in WT, but not in KO mice. Moreover, in the feed group, there was no difference in the weight of the internal organs between the WT and KO mice, but in the pupae-fed group, liver weight was decreased and spleen weight was increased compared with that of KO mice. The amounts/plural/amounts of Melainabacteria, Chloroflexi, and Armatimonadetes were specifically upregulated by pupae, and this upregulation was weakened or eliminated by PD-1H depletion. Some bacteria with high abundance in the feed-fed KO mice, such as Deferribacteres, Melainabacteria, Acidobacteria, Bacteroidetes, Spirochaetes and Verrucomicrobia, were decreased in pupae-fed KO mice, and Proteobacteria and Deinococcus were specifically enriched in pupae-fed KO mice. Bacteroidetes, Firmicutes and Akkermansia were associated with weight loss in the pupaefed group while Lachnospiraceae and Anaerobiospirillum were related glucose metabolism and energy consumption. Based on high-throughput sequencing, we discovered that some gut bacteria specifically regulated the metabolism of a high-protein diet, and PD-1H deficiency improved life quality and sustained blood glucose. Moreover, PD-1H responses to high-protein diet through modulating the type and quantity of gut bacteria. These findings provide evidence about the association among gut microbiota, T cell activation (for PD-1H depletion) and high-protein diet metabolism, have important theoretical significance for nutrition and health research.

Aircraft Fuel Delivery System Failure Modeling Analysis Using Maintenance Aware Design Environment Software

Gang Niu,Yajun Zhao 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.10

A Joint Design for Multi-band Heterogeneous Networks when Deploying Reconfigurable Intelligent Surface

Wenyu Jiang,Kaizhi Huang,Yajun Chen,Xiaoli Sun,Jie Yang,Kai Zhao 한국통신학회 2022 Journal of communications and networks Vol.24 No.5

Reconfigurable Intelligent Surface (RIS) technique is effective to improve the capacity and coverage of various networks. However, the practical RIS has dissimilar responses to signals in different frequencies due to its structure. Therefore, directly applying existing schemes to multi-band heterogeneous networks leads to beam misalignment and performance degra- dation issues. This paper considers RIS-assisted multi-band heterogeneous networks where base stations (BSs) use different frequencies. We formulate the problem for maximizing the sum rate of all users (SR) in every frequency band, and aim to jointly design BSs precoding vectors and RIS parameters while taking user choices into account. Based on the closed-form relationship of phase shifts between frequencies, an iterative algo- rithm is proposed to solve the challenging non-convex problems. In particular, we use fractional programming to decouple the problem, and solve the subproblems with Quadratic Transform (QT) and Genetic Algorithm (GA). Simulation results show that the proposed scheme can significantly improve SR among all frequency bands, which could instruct the coexistence of mul- tiple communication systems in future heterogeneous networks. What’s more, results also prove that deploying RISs recklessly will result in a degradation of the network.

Mitochondrial Location of Severe Acute Respiratory Syndrome Coronavirus 3b Protein

Yuwen Cong,Xiaoling Yuan,Yajun Shan,Zhenyu Yao,Jianyong Li,Zhenhu Zhao,Jiapei Chen 한국분자세포생물학회 2006 Molecules and cells Vol.21 No.2

A 2-40 Gb/s PAM4/NRZ Dual-mode Wireline Transmitter with 4:1 MUX in 65-nm CMOS

Fangxu Lv,Xuqiang Zheng,Feng Zhao,Jianye Wang,Ziqiang Wang,Shuai Yuan,Yajun He,Chun Zhang,Zhihua Wang 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.2

This paper presents a 2-40 Gb/s dual-mode wireline transmitter supporting the four-level pulse amplitude modulation (PAM4) and non-return-tozero (NRZ) modulation with a multiplexer (MUX)-based two-tap feed-forward equalizer (FFE). An edgeacceleration technique is proposed for the 4:1 MUX to increase the bandwidth. By utilizing a dedicated cascode current source, the output swing can achieve 900 mV with a level deviation of only 0.12% for PAM4. Fabricated in a 65-nm CMOS process, the transmitter consumes 117 mW and 89 mW at 40 Gb/s in PAM4 and NRZ at 1.2 V supply.