Performance Analysis of Energy-Efficient Secure Transmission for Wireless Powered Cooperative Networks with Imperfect CSI

Yajun Zhang,Jun Wu,Bing Wang,Hongkai Wang,Xiaohui Shang 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.9

The paper focuses on investigating secure transmission in wireless powered communication networks (WPCN) that involve multiple energy-constrained relays and one energy-constrained source. The energy is harvested from a power beacon (PB) while operating in the presence of a passive eavesdropper. The study primarily aims to achieve energy-efficient secure communications by examining the impact of channel estimation on the secrecy performance of WPCN under both perfect and imperfect CSI scenarios. To obtain practical insights on improving security and energy efficiency, we propose closed-form expressions for secrecy outage probability (SOP) under the linear energy harvesting (LEH) model of WPCN. Furthermore, we suggest a search method to optimize the secure energy efficiency (SEE) with limited power from PB. The research emphasizes the significance of channel estimation in maintaining the desired performance levels in WPCN in real-world applications. The theoretical results are validated through simulations to ensure their accuracy and reliability.

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.

중국 하남성 고교 여자축구선수의 또래관계 및 사회적 행동의 관계

장아군(Zhang YaJun),이병찬(Lee, Byung-Chan),이경선(Lee, Kyong-Sun) 한국체육과학회 2019 한국체육과학회지 Vol.28 No.5

The purpose of this study was to examine the relationship between peer-relationship, self-perceived competence and social behavior. To obtain the purpose, female high school soccer players(N=650) participating in A and B class competitions in Henan province, China were recruited via the stratified sampling. 650 questionnaires were distributed and 561 cases were finally analyzed, 89 questionnaires were excluded as unfaithfully answered. The study examined peer-relationship and social behavior through frequency analysis, confirmatory factor analysis, correlation analysis, and multiple linear regression analysis. As the effect of the peer-relationship on social behavior, the sub-factors, such as self-expression and acceptance, of peer-relationship had a negative impact on misdeed behavior. However, the peer-relationship on social behavior, the sub-factors, such as conflict and exclusiveness, of peer-relationship had a positive impact on misdeed behavior while such factors indicated a negative impact on competitive behavior. Moreover, conflict and exclusiveness of peer-relationship had a negative impact on sociable behavior while self-expression and acceptance had a positive effects.

여자축구선수의 역량지각과 사회적 행동 간 관계 연구 : 중국 하남성 고등학생을 대상으로

장아군(Zhang YaJun),김주영(Kim, Joo-Young),김판수(Kim, Pan-Soo) 한국체육과학회 2019 한국체육과학회지 Vol.28 No.6

The purpose of this study is to examine the relationship between self-perceived competence and social behavior of female high school football player. To achieve the goal, female high school football players(N=650) participating in competitions in Henan province. 650 questionnaires were distributed and 561 cases were used for final analyze and 89 questionnaires were excluded. The study analyzed relationship between self-perceived and social behavior by frequency, confirmatory factor analysis, correlation analysis, and multiple linear regression analysis. As the effect of the self-perceived competence on social behavior, motor and physical competence showed a negative effects on misdeed behavior whilst such sub-factors had a positive impact on competitive behavior. In fact, the sub-factor of attitude indicated a negative effect on competitive behavior. Finally, motor, physical, social competence had a positive effect on sociable behavior. Implications of this study were discussed and the directions for the future research were suggested.

White-light crosslinkable milk protein bioadhesive with ultrafast gelation for first-aid wound treatment

Zhu Qinchao,Zhou Xuhao,Zhang Yanan,Ye Di,Yu Kang,Cao Wangbei,Zhang Liwen,Zheng Houwei,Sun Ziyang,Guo Chengchen,Hong Xiaoqian,Zhu Yang,Zhang Yajun,Xiao Ying,Valencak Teresa G.,Ren Tanchen,Ren Daxi 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background : Post-traumatic massive hemorrhage demands immediately available first-aid supplies with reduced operation time and good surgical compliance. In-situ crosslinking gels that are flexibly adapting to the wound shape have a promising potential, but it is still hard to achieve fast gelation, on-demand adhesion, and wide feasibility at the same time. Methods : A white-light crosslinkable natural milk-derived casein hydrogel bioadhesive is presented for the first time. Benefiting from abundant tyrosine residues, casein hydrogel bioadhesive was synthesized by forming di-tyrosine bonds under white light with a ruthenium-based catalyst. We firstly optimized the concentration of proteins and initiators to achieve faster gelation and higher mechanical strength. Then, we examined the degradation, cytotoxicity, tissue adhesion, hemostasis, and wound healing ability of the casein hydrogels to study their potential to be used as bioadhesives. Result : Rapid gelation of casein hydrogel is initiated with an outdoor flashlight, a cellphone flashlight, or an endoscopy lamp, which facilitates its usage during first-aid and minimally invasive operations. The rapid gelation enables 3D printing of the casein hydrogel and excellent hemostasis even during liver hemorrhage due to section injury. The covalent binding between casein and tissue enables robust adhesion which can withstand more than 180 mmHg blood pressure. Moreover, the casein-based hydrogel can facilitate post-traumatic wound healing caused by trauma due to its biocompatibility. Conclusion : Casein-based bioadhesives developed in this study pave a way for broad and practical application in emergency wound management.

Enhancement of thermal stability and chemical reactivity of phenolic resin ameliorated by nanoSiO2

Yajun Guo,Lihong Hu,Puyou Jia,Baofang Zhang,Yonghong Zhou 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

Phenolic resin has unsatisfactory thermal stability owing to the poor anti-oxidation property of methylene and phenol groups. To overcome this defect, a series of phenolic resin modified by nanoSiO2 based on the tetraethoxysilane (TEOS) was successfully prepared via sol-gel method using phenol as solvent. The effect of nanoSiO2 on the structures and properties of phenolic resin/foam was investigated. TGA and DTG indicated that the initial decomposition temperature of PR-0.5 (TEOS accounted for 0.5% of phenolic resin) was 41.8 oC higher than the neat PR-0. DSC revealed that the peak temperature presented a parabolic shape with the dosage of the TEOS, its maximal value resting on the PR-0.5. FT-IR and XRD demonstrated that chemical crosslink was reacted between PR and nanoSiO2 hydrolyzed by the TEOS, forming new chemical bands. Reactivity analysis illustrated that the free phenol content and the hydroxymethyl group content changed sharply in PF-0.5, implying it has highest reactivity.

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.

Characterization and identification of OsFTL8 gene in rice

Zhang Siju,Jin Yajun,Hao Hongjiao,Liang Shanshan,Ma Xuan,Luan Weijiang 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.6

The rice genome contains 13 Flowering Locus T-Like (FT-Like) genes, among which, OsFTL2/Hd3a and OsFTL3/RFT1 are characterized as forigen-encoding genes, promoting rice fowering under short-day and long-day conditions, respectively. However, the functions of the other FT-Like members are still unknown in rice. In this study, we characterized and identifed a member of FT-Like family, OsFTL8 gene. The investigation of photoperiodic expression pattern showed that OsFTL8 transcription was mainly induced under short-day conditions. The qRT-PCR and GUS staining assays indicated that OsFTL8 was broadly expressed in various organs, including stems, leaves and panicles. OsFTL8 overexpression transgenic lines and its knockout mutants displayed no obvious change in their heading date, compared with the wild type. However, the pollen viability and seed setting rate were decreased in the overexpression transgenic lines. OsFTL8 localizes in both nucleus and cytoplasm. And we found that OsFTL8 does not interact with OsFD1 in vivo, suggesting that OsFTL8 may not be the component of forigen activation complex (FAC). In summary, our results indicate that OsFTL8 is associated with pollen viability and not involved in regulating rice fowering time, implying functional divergence of FT-Like members.

CO2 Capture on a Novel Porous Silicate Material from Coal Gangue: Equilibrium, Kinetic, and Thermodynamic Studies

Yajun Gao,Hong Du,Yu Wu,Kai Liu,Jianbin Zhang 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.2

The adsorption of CO2 on a novel porous silicate material (PSM) from coal gangue at T = (288.15, 303.15, and 318.15) K was thoroughly characterized, and the experimental results showed that the adsorption capacity increased with the increasing pressures. Furthermore, the isotherm data were well fitted to Double–Langmuir model, and the adsorption process was found to be exothermic in nature with a decrease in entropy. Meanwhile, thermodynamic results also showed that the adsorption occurred via a spontaneous and enthalpy driven process and controlled by physisorption. In addition, the adsorption performance was still stable after 10 times adsorption—desorption cycles, which indicated that the PSM had a positive regeneration performance.

Rapid Detection of Lily mottle virus and Arabis mosaic virus Infecting Lily (Lilium spp.) Using Reverse Transcription Loop-Mediated Isothermal Amplification

Yubao Zhang,Yajun Wang,Zhongkui Xie,Ruoyu Wang,Zhihong Guo,Yuhui He 한국식물병리학회 2020 Plant Pathology Journal Vol.36 No.2

The Lily mottle virus (LMoV) impedes the growth and quality of lily crops in Lanzhou, China. Recently Arabis mosaic virus (ArMV) has been detected in LMoV- infected plants in this region, causing plant stunting as well as severe foliar symptoms, and likely posing a threat to lily production. Consequently, there is a need to develop simple, sensitive, and reliable detection methods for these two viruses to prevent them from spreading. Reverse transcription (RT) loop-mediated isothermal amplification (LAMP) assays have been de- veloped to detect LMoV and ArMV using two primer pairs that match six conserved sequences of LMoV and ArMV coat proteins, respectively. RT-LAMP assay results were visually assessed in reaction tubes using green fluorescence and gel electrophoresis. Our assays successfully detected both LMoV and ArMV in lily plants without the occurrence of viral cross-reactivity from other lily viruses. Optimal conditions for LAMP reactions were 65°C and 60°C for 60 min for LMoV and ArMV, respectively. Detection sensitivity for both RT-LAMP assays was a hundredfold greater than that of our comparative RT-polymerase chain reaction as- says. We have also found this relatively rapid, target specific and sensitive method can also be used for samples collected in the field and may be especially useful in regions with limited or no laboratory facilities.