A New Design Strategy for Observing Lithium Oxide Growth-Evolution Interactions Using Geometric Catalyst Positioning

Ryu, Won-Hee,Gittleson, Forrest S.,Li, Jinyang,Tong, Xiao,Taylor, André,D. American Chemical Society 2016 NANO LETTERS Vol.16 No.8

<P>Understanding the catalyzed formation and evolution of lithium-oxide products in Li-O-2 batteries is central to the development of next-generation energy storage technology. Catalytic sites, while effective in lowering reaction barriers, often become deactivated when placed on the surface of an oxygen electrode due to passivation by solid products. Here we investigate a mechanism for alleviating catalyst deactivation by dispersing Pd catalytic sites away from the oxygen electrode surface in a well-structured anodic aluminum oxide (AAO) porous membrane interlayer. We observe the cross-sectional product growth and evolution in Li-O-2 cells by characterizing products that grow from the electrode surface. Morphological and structural details of the products in both catalyzed and uncatalyzed cells are investigated independently from the influence of the oxygen electrode. We find that the geometric decoration of catalysts from the conductive electrode surface significantly improves the reaction reversibility by chemically facilitating the oxidation reaction through local coordination with PdO surfaces. The influence of the catalyst position on product composition is further verified by ex situ X-ray photoelectron spectroscopy and Raman spectroscopy in addition to morphological studies.</P>

An Analysis of Internet Censorship Circumvention Techniques

Tianbo Lu,Jinyang Zhao,Lingling Zhao,Yang Li,WanJiang Han 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.5

Since Internet was born, it has deeply influenced almost every aspects of people’s life. However, at the mean time when people enjoy the convenience brought by the Internet, there is censorship existed every corner of the internet world. Censorship circumvention technique to protect people’s communication against censors. During the past decades, anti-censorship techniques have a broad and extensive development, however not all of the censorship circumvention techniques have effect in circumvent the censors and there is still not a very useful and convenient technique to ensure the anonymity of internet communication. In this paper, we tried to analyze the current situation of censorship and anti-censorship techniques and give a comprehensive view on the censorship circumvention techniques and systems.

Geometric Nonlinear Static Aeroelastic Characteristics Analysis of High-Aspect-Ratio Wing with Large Deformation

Junli Wang,Jinyang Li,Shuai Lei,Zhigui Ren,Yayin He 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.2

To explore the geometric nonlinearity of high-aspect-ratio wing due to large deformation, the aerodynamics were solved by Navier–Stokes governing equation based on the loose coupling method of CFD/CSD. Considering the large displacement stiffness matrix of wing structure, the Newton–Raphson method is used to solve the nonlinear elastic deformation of the structure. A geometrically nonlinear static aeroelastic coupling calculation program is developed. During the coupling process, an improved elastic approximation method was used to update the aerodynamic mesh, and the data exchange on the coupling interface was realized by a fixed-volume interpolation method. The reliability of the proposed method was verified by HIRENASD wing model. Finally, the effects of geometric nonlinear static aeroelasticity on longitudinal aerodynamic characteristics and stability of swept wing with high aspect ratio at different angles of attack are studied using this method. The results show that the lift direction of a high-aspect-ratio wing is significantly deformed under the influence of aerodynamic loads. The effective angle of attack of the wing decreases with the whole deformation, and the degree of decrease increases from the root to the tip. The significant flexural and torsional deformation will change the lift coefficient and drag coefficient of the wing and reduce the margin of the static stability of the wing.

Differential Response of Two Contrasting Melon (Cucumis melo L.) Genotypes to Drought Stress

Asad Rehman,Jinyang Weng,Pengli Li,Jing Yu,Saeed ur Rahman,Muhammad Khalid,Iftikhar Hussain Shah,Shazma Gulzar,Liying Chang,Qingliang Niu 한국식물학회 2023 Journal of Plant Biology Vol.66 No.6

The present study aims to gain insights into the response mechanisms of drought stress tolerance among two contrasting melon (Cucumis melo L.) genotypes. Drought stress was imposed by polyethylene glycol (10%) for 7 days and various physiochemical and molecular characteristics were analyzed on different days of drought stress treatment. Results revealed that the drought-sensitive genotype (MG-II) was significantly affected by drought stress, as evidenced from the elevation in hydrogen peroxide (H2O2), malondialdehyde content (MDA), and electrolyte leakage (EC). Furthermore, drought stress significantly hindered the vegetative growth, chlorophyll fluorescence, photosynthetic pigments, and leaf gas exchange characteristics of MG-II genotypes. In contrast, the drought-resistant genotype (MG-I) exhibited a robust response to drought stress, characterized by marked upregulation in the antioxidant enzyme genes and activities, which in turn resulted in a decrease in oxidative damage and improved vegetative growth and photosynthetic functions. Additionally, transmission electron microscopy (TEM) revealed that the oxidative damage triggered by drought stress was more severe in the MG-II genotype, which exhibited an irregular chloroplast shape compared to the MG-I. These findings may potentially enhance our comprehension of coping strategies involved in drought stress tolerance and provide materials for future melon breeding and molecular studies.

Towards a Framework for Assuring Cyber Physical System Security

Tianbo Lu,Jinyang Zhao,Lingling Zhao,Yang Li,Xiaoyan Zhang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.3

Today, cyber physical systems (CPS) are becoming popular in power networks, healthcare devices, transportation networks, industrial process and infrastructures. As cyber physical systems are used more and more extensively and thoroughly, security of cyber physical systems has become the utmost important concern in system design, implementation and research. Many kinds of attacks arise (e.g. the Stuxnet worm), causing heavy losses and serious potential security risks. For the past few years, researchers are focusing their researches on different aspects of security of cyber physical systems. In this paper, we propose a security framework assuring the security of cyber physical systems and analyze main universities and institutes studying CPS security and their relations in three levels: CPS security objectives, CPS security approaches and security in specific CPS applications. Finally, a conclusion of this article is given.

Modulation method of parallel interleaved three‑level inverter considering neutral point potential and phase current balance

Ying Zhong,Weichao Li,Liang Zhou,Chen Deng,Jinyang Han 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.2

The capacity and equivalent switching frequency of parallel interleaved inverters can be increased, but there are problems with neutral point potential balance and parallel bridge circulating current. This paper regards the parallel three-level inverter as a five-level inverter and five-level space vector integrated modulation is applied. On this basis, a neutral-point potential control strategy based on the mid-point charge to calculate the adjustment factor k is proposed. By further meticulously partitioning specific sector regions, the selection method of redundant vectors in the switching sequence is optimized without increasing the switching times, and the midpoint voltage ripple is reduced. Then, the redundant state allocation in the process of splitting the five-level into three-level is used as a new degree of freedom to suppress the circulating current of the parallel bridge, therefore realizing the control of voltage and current sharing. Finally, simulation and experiments verify the correctness and effectiveness of the method.

Test Study on the Air Permeability of Remolded Q3 Malan Loess

Jia Liu,Xi’an Li,Zeze Guo,Quan Xue,Li Wang,Jinyang Liu 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.8

Gas permeability is an important parameter in the determination of the pore structure characteristics of loess, especially in engineering fields such as earthwork and landfill cover treatment. With an improved ZC-2015 air permeameter, the air permeability (ka) testing under different water contents (w), dry densities (ρd) and wetting paths was conducted on remolded Q3 Malan loess from the Chanhe River area in Xi’an, Shaanxi, China. The results indicate that the ka of the remolded loess decreased rapidly as ρd increased and exhibited a relatively complex pattern as w increased. When w was less than the plastic limit (wp) and ρdwas relatively low (1.35 g·cm−3, 1.45 g·cm−3), ka decreased as we increased. When ρd reached a certain value (1.50 g·cm−3, 1.65 g·cm−3), the ka–we curve exhibited a notable turning point. When ρd continued to increase 1.70 g·cm−3, ka decreased as we increased. The results of microscopic analysis, suggested that under the action of different water content and compaction, levels of aggregates and pore structures were formed. A Poulsen model was used to predict the ka and the test results were in relatively coincident with the calculation results, demonstrating that the Poulsen model is applicable.

Effect of Co-W and Co-Fe-W diffusion barriers on the reliability of the Solder/Cu interface during reflow conditions

Yuexiao Liu,Chongyang Li,Peixin Chen,Jinyang Liu,Anmin Hu,Ming Li 대한금속·재료학회 2024 ELECTRONIC MATERIALS LETTERS Vol.20 No.5

Efficient diffusion barriers are necessary to prevent the formation of copper-tin intermetallic compounds (IMCs) inadvanced packaging for Sn/Cu micro-bumps. This study investigated the interfacial properties of solder and Ni, Co-9W,Co-20W, Co-20Fe-10W, and Co-36Fe-17W barriers and determined the thickness of IMCs formed between Sn and thesebarriers after up to 15 refl ows. Among the fi ve barriers, Co-36Fe-17W proved to be the most eff ective in inhibiting thereaction of liquid Sn solder. At the Sn/Co-W interface, CoSn 3 IMC was formed, while at the Sn/Co-Fe-W interface, CoSn 3IMC and FeSn 2 IMC were observed. The contact angles of these layers were measured and found to be 18°, 22°, 25°,29°, and 27°, respectively. The results showed that an increase in W content in Co-W led to an increase in the contactangle, while the intrinsic wettability of Co-Fe-W decreased with an increase in Fe content. The shear strengths of the fi vejoints were 27 MPa, 31 MPa, 25 MPa, 25 MPa, and 26 MPa, respectively, with diff erent fracture modes observed. TheCo-Fe-W-Sn layer was partially peeling from the diffusion barriers in SAC305/Co-20Fe-10W, and the fracture surfacesexhibited an irregular and rough state, which was attributed to the increasing Fe and W contents. These fi ndings off ervaluable insights for enhancing the reliability of electronic packages.

Variable Coefficient Inductance Model-Based Four-Quadrant Sensorless Control of SRM

Kuai, Song-Yan,Li, Xue-Feng,Li, Xing-Hong,Ma, Jinyang The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

The phase inductance of a switch reluctance motor (SRM) is significantly nonlinear. With different saturation conditions, the phase inductance shape is clearly changed. This study focuses on the relationship between coefficient and current in an inductance model with ignored harmonics above the order of 3. A position estimation method based on the variable coefficient inductance model is proposed in this paper. A four-quadrant sensorless control system of the SRM drive is constructed based on the relationship between variable coefficient inductance and rotor position. The proposed algorithms are implemented in an experimental SRM test setup. Experimental results show that the proposed method estimates position accurately in operating two/four-quadrants. The entire system also has good static and dynamic performance.

Study on Deterioration Characteristics and Fracturing Mechanism of Concrete Under Liquid Nitrogen Cold Shock

Jialiang Liu,Yu Jin,Yujie Zhu,Jinyang Li,Xuguang Zhang,Chao Tao 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.1