Synthesis of stabilizer-free small PdAg alloy nanoparticles supported on carbon using a continuous Couette-Taylor reactor with enhanced electrochemical activity toward ethanol oxidation reaction

JIANG PENGFEI,Hyun Jiyu,박현수,방석호,김우식,유태경 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

An organic surfactant/stabilizer plays a critical role in synthesizing small and well-dispersed nanoparticles with large catalytic surface areas. However, a stabilizer typically interferes with the catalytic reaction by forming organic layers on the surface of nanoparticles. Here, we report that the role of a stabilizer can be replaced by the periodic and uniform fluid shear of Taylor vortex flow. Small, well-dispersed PdAg alloy nanoparticles on carbon were synthesized in the continuous Couette-Taylor (CT) reactor in the absence of a stabilizer. The synthesized PdAg nanoparticles (Pd64Ag36/C) showed two times higher mass activity than commercial Pd/C and good stability (retained 33% after 3,600 s) toward the electrochemical ethanol oxidation reaction due to their clean surface and alloy structure.

The Prognostic Value of CD8+ and CD45RO+ T Cells Infiltration and Beclin1 Expression Levels for Early Postoperative Cholangitis of Biliary Atresia Patients after Kasai Operation

Hong Jiang,Pengfei Gao,Huadong Chen,Zhihai Zhong,Man Shu,Zhichong Zhang,Jinbiao She,Juncheng Liu 대한의학회 2018 Journal of Korean medical science Vol.33 No.30

Background: Postoperative cholangitis is a common but severe complication after Kasai portoenterostomy for biliary atresia (BA). This study aimed to identify its prognostic factors Methods: Two sets of liver paraffin-embedded tissue samples were collected from BA patients who received Kasai portoenterostomy (n = 25 and n = 31, respectively). Patients were divided into non-cholangitis and cholangitis groups. The infiltration of CD4+ , CD8+ , CD45RO+ , CD68+ cells and expression of Beclin1 were quantitatively evaluated in immunohistochemical analysis. Results: Cholangitis group had a significantly lower CD8+ T cell infiltration but a higher CD45RO+ cell infiltration, and a lower Beclin1 level than non-cholangitis group (all P < 0.01). Multivariate logistic regression analysis indicated that infiltration of CD8+ cells (odds ratio [OR], 0.112; 95% confidence interval [CI], 0.022–0.577) and CD45RO+ cells (OR, 3.88; 95% CI, 1.37–11.03), and Beclin1 level (OR, 0.088; 95% CI, 0.018–0.452) were independent influence factors for early postoperative cholangitis. Receiver operating characteristic (ROC) analysis showed that area under ROC curve (AUROC) values for CD8+ cells, CD45RO+ cells and Beclin1 were 0.857, 0.738 and 0.900, respectively. Conclusion: Our findings demonstrated the CD8+ cells, CD45RO+ cells and Beclin1 level possessed the prognostic value for early postoperative cholangitis following Kasai operation, which may be helpful to develop new prevention and treatment strategies for postoperative cholangitis.

Three-Dimensional Analysis of Chloroplast Structures Associated with Virus Infection

Jin, Xuejiao,Jiang, Zhihao,Zhang, Kun,Wang, Pengfei,Cao, Xiuling,Yue, Ning,Wang, Xueting,Zhang, Xuan,Li, Yunqin,Li, Dawei,Kang, Byung-Ho,Zhang, Yongliang American Society of Plant Biologists 2018 Plant Physiology Vol.176 No.1

<P>Three-dimensional visualization identifies structural remodeling in chloroplasts during barley stripe mosaic virus infection.</P><P>Chloroplasts are multifunctional organelles whose morphology is affected by environmental stresses. Although the three-dimensional (3D) architecture of thylakoid membranes has been reported previously, a 3D visualization of chloroplast under stress has not been explored. In this work, we used a positive-strand RNA ((+)RNA) virus, barley stripe mosaic virus (BSMV) to observe chloroplast structural changes during infection by electron tomography. The analyses revealed remodeling of the chloroplast membranes, characterized by the clustering of outer membrane-invaginated spherules in inner membrane-derived packets. Diverse morphologies of cytoplasmic invaginations (CIs) were evident with spherules at the periphery and different sized openings connecting the CIs to the cytoplasm. Immunoelectron microscopy of these viral components verified that the aberrant membrane structures were sites for BSMV replication. The BSMV αa replication protein localized at the surface of the chloroplasts and played a prominent role in eliciting chloroplast membrane rearrangements. In sum, our results have revealed the 3D structure of the chloroplasts induced by BSMV infection. These findings contribute to our understanding of chloroplast morphological changes under stress conditions and during assembly of plant (+)RNA virus replication complexes.</P>

Accurate segmented equivalent circuit‑based calculation approach for non‑ideal stranded Litz wire leakage energy

Bin Chen,Pengfei Jiang,Nina Wan,Bo Tang 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

Existing calculations of leakage energy in the Litz wire winding region of high-frequency transformers usually ignore the influence of Litz wire stranded structures. Therefore, a new approach is established in this paper to accurately calculate Litz wire leakage energy through the segmented equivalent circuit approach and the two-dimensional finite element method. That is, a single Litz wire in a complete stranded pitch is segmented and equated to the linear structure of multiple inductance cells. First, the two-dimensional finite element method calculates the impedance of each strand of Litz wire. Then the strand current vector is solved according to the system equation. Finally, the current vector is substituted back into the 2D Litz wire transverse-sectional model to calculate the leakage magnetic field energy under the skin effect and internal proximity effect, which is combined with the analytical expression of the external leakage magnetic field to calculate the total magnetic leakage energy of the Litz wire winding. Calculation results indicate that the new approach has an average relative deviation of less than 2.154% and a maximum relative deviation of no more than 4.953%.

One-step Synthesis Pd@Pt Core-Shell Concave Cube by Facile Reduction Control toward formic acid oxidation reaction

( Xiao ),( Cun Liu ),( Pengfei Jiang ),유태경 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

The core-shell Pd@Pt nanocubes were successfully designed as concave structure by a galvanic replacement, one-step process. In this study, we chose the ascorbic acid and citric acid as the different strength reduction to facile control the Pd@Pt crystal growth. Firstly, the Pd nanocube formed using ascorbic acid as stronger reducing agent with accuracy control amount. In general, the different intensities reducing agent ascorbic acid and citric acid are the key-points to kinetic control the concave structure formed and the Br^- play the major role to enhance the galvanic replacement reaction between Pt(II)Cl₄^2-and Pd. In addition, the concave cubic Pd@Pt nanocrystal exhibited higher electrochemical performance compare to commercial Pt electrocatalyst toward formic acid oxidation reaction.

Analysis of the Operating Efficiency and Influencing Factors of E-commerce Companies in China: Based on DEA-Tobit Regression Model

Na, Sang-Gyun(나상균),Pengfei Gui(계붕비),QingYun Jiang(장청운) 한국경영교육학회 2019 경영교육연구 Vol.34 No.3

[연구목적] 본 연구는 중국의 전자 상거래 기업을 대상으로 경영효율성을 측정하고, 경영효율성에 영향을 미치는 환경요인이 효율성에 어떠한 영향을 미치는지 분석함으로써 전자상거래 기업의 경영효율성을 결정하는 요인을 추정하고, 그 결과를 바탕으로 경영효율성의 평가와 운영의 효율성을 제고하는 데 연구의 목적이 있다. [연구방법] SBM-DEA 모형을 이용하여 상장 된 42개 전자상거래 기업의 경영효율성을 2단계 DEA 모형을 적용한 Tobit 회귀분석을 수행하였다. [연구결과] 상장 전자 상거래 기업들은 전체 기술효율 평균값 0.518로 나타나, 효율성의 향상시킬 수 있는 여지가 있는 것으로 분석되었다. 또한 전체적으로 전자 상거래 기업들은 과도 투입이나 산출 부족의 문제가 존재하는 것으로 분석되었다. 또한 총 자산 회전율, 순이익 및 브랜드 가치 인식이 전자상거래 기업 운영의 효율성에 중요한 요소로 분석되었다. [연구의 시사점] 전자 상거래 기업들은 경영의 효율성을 추구하기 위해서는 기술 및 경영 수준을 지속적으로 개선해야 하고 경영 자원 배분을 최적화하며, 기술 효율성을 지속적으로 개선할 필요가 있음을 시사할 수 있다. [Purpose] This study measured the operating efficiency and analyzed the environmental factors affecting operational efficiency by using 42 listed e-commerce companies in China. The purpose is to evaluate the efficiency of e-commerce operations and improve the efficiency of e- commerce operations. [Methodology] This study used the SBM-DEA model to determine the operating efficiency of 42 listed e-commerce companies. The 2-stage DEA model used the Tobit regression model for regression analysis. [Findings] The average technical efficiency of listed e-commerce companies is 0.518, indicating that there is room for improvement in efficiency. Overall, e-commerce companies have problems with excessive investment or lack of output. In addition, total asset turnover, net profit and brand value perception are important factors in operational efficiency. [Implications] In order to pursue management efficiency, e-commerce enterprises need to continuously improve their technology and management level, optimize management resource allocation, and continuously improve technical efficiency.

Transient Stability Simulation Analysis of Multi Node Power Network with Variable Speed Pumped Storage Units

Zhao Chong,Wang Longze,Ma Yiyi,Xiang Pengfei,Jiang Siyu,Chen Weidong,Zhang Yan,Li Meicheng 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

The output characteristics of variable speed pumped storage are different from conventional hydropower and constant speed pumped storage units. The continuous increase of installed capacity of variable speed pumped storage, poses a severe challenge to the safe and stable operation of the local power grid. Proposed in this paper is a kind suitable for multi-node containing variable speed pump machine storage unit electric power network transient stability method, considering the variable speed pumped storage units by the end of the instantaneous failure prone to sudden drop transient power, the power network with more nodes each busbar voltage stable operation as the goal, according to the regional power grid data under typical operation modes, Based on the power system analysis software package, an electromechanical simulation model of the 7-node power grid with variable speed pumped storage unit was established. The influence on the transient stability of a 7-node power grid is analyzed by removing variable speed pumped-storage units and three-phase short-circuit faults. The transient stability of the power grid can be maintained under the conditions of removing variable speed pumped-storage units and three-phase short-circuit faults, but some bus voltages are higher than the specified voltage upper limit. The reactive power compensation device is installed to improve the voltage stability of the power grid system, which can prevent the overvoltage accident caused by the fault of the communication system, achieve the purpose of multi-node power network stability, and improve the safety and stability of the regional power system when the fault occurs.