From structure to function: Harnessing the ionic conductivity of covalent organic frameworks

Liu Cong‐Xue,황수민,우혜린,이은성,박선아 대한화학회 2024 Bulletin of the Korean Chemical Society Vol.45 No.4

Rapid advancements in energy storage technology, driven by a growing demand for energy storage devices, underscore the crucial need to comprehend ionic conduction behavior. Consequently, intensive research on high‐performance ionic conductors becomes imperative. Covalent organic frameworks (COFs) have emerged as invaluable materials in the realm of solid‐state or quasi‐solid‐state ion‐conduction, leveraging their unique properties such as significant porosity, tunability, and robust physicochemical durability. These distinctive attributes position COFs as promising candidates for the development of electrodes, electrolytes, and separator materials characterized by high capacities, rapid ion transport, and electrochemical stability. This review provides insights into COFs as ionic conductors, discusses recent advancements in COF‐based energy storage devices, and explores the influence of structural functionalization, pore size engineering, and dimensional regulation on ionic conduction. Moreover, the review aims to deepen understanding and pave the way for future advancements in the utilization of COFs within energy storage technologies. Rapid advancements in energy storage technology, driven by a growing demand for energy storage devices, underscore the crucial need to comprehend ionic conduction behavior. Consequently, intensive research on high-performance ionic conductors becomes imperative. Covalent organic frameworks (COFs) have emerged as invaluable materials in the realm of solid-state or quasi-solid-state ion-conduction, leveraging their unique properties such as significant porosity, tunability, and robust physicochemical durability. These distinctive attributes position COFs as promising candidates for the development of electrodes, electrolytes, and separator materials characterized by high capacities, rapid ion transport, and electrochemical stability. This review provides insights into COFs as ionic conductors, discusses recent advancements in COF-based energy storage devices, and explores the influence of structural functionalization, pore size engineering, and dimensional regulation on ionic conduction. Moreover, the review aims to deepen understanding and pave the way for future advancements in the utilization of COFs within energy storage technologies.

Simulation Analysis of Cylinder Impact Performance Influenced by Shaft Sleeve Structure

Cong Liu,Pei Xiao,Xingli Li,Gangyan Li 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.1

To study the cylinder motion characteristics, cylinder and shaft sleeve stress characteristics of cylinder stroke and return process influenced by different shaft sleeve structure, the cylinders with non-chamfering shaft sleeve, C0.3 chamfering shaft sleeve and R0.3 round corner shaft sleeve were used for simulation of cylinder stroke and return process. The results show that the piston velocity curves of three kinds of shaft sleeve are identical. Maximum stress of different shaft sleeves fluctuates and maximum stress elements of C0.3 and R0.3 shaft sleeve are similar. When cylinder strokes, maximum stress of cylinder occurs at the end of piston rod connected to the load; the stress of C0.3 shaft sleeve is the lowest. When cylinder returns, maximum stress of cylinder occurs at the shaft sleeve; the stress of C0.3 and R0.3 shaft sleeve differ little and are both lower than that of non-chamfering shaft sleeve. It provides a reference for structure optimization and service life improvement of the cylinder shaft sleeve.

Simulation Analysis of Cylinder Impact Performance Influenced by Shaft Sleeve Structure

Liu, Cong,Xiao, Pei,Li, Xingli,Li, Gangyan Korean Society for Fluid machinery 2018 International journal of fluid machinery and syste Vol.11 No.1

To study the cylinder motion characteristics, cylinder and shaft sleeve stress characteristics of cylinder stroke and return process influenced by different shaft sleeve structure, the cylinders with non-chamfering shaft sleeve, C0.3 chamfering shaft sleeve and R0.3 round corner shaft sleeve were used for simulation of cylinder stroke and return process. The results show that the piston velocity curves of three kinds of shaft sleeve are identical. Maximum stress of different shaft sleeves fluctuates and maximum stress elements of C0.3 and R0.3 shaft sleeve are similar. When cylinder strokes, maximum stress of cylinder occurs at the end of piston rod connected to the load; the stress of C0.3 shaft sleeve is the lowest. When cylinder returns, maximum stress of cylinder occurs at the shaft sleeve; the stress of C0.3 and R0.3 shaft sleeve differ little and are both lower than that of non-chamfering shaft sleeve. It provides a reference for structure optimization and service life improvement of the cylinder shaft sleeve.

Bubbles and Blisters Impact on Diecasting Cage to the Designs and Operations of Line-Start Synchronous Reluctance Motors

Liu, Huai-Cong,Hong, Hyun-Seok,Cho, Sooyoung,Lee, Ju,Jin, Chang-Sung IEEE 2017 IEEE transactions on magnetics Vol.53 No.6

<P>This study investigates the starting capability of a high-efficiency synchronous reluctance motor for direct online industrial applications. Because of structural limitations, line-start synchronous reluctance motors (LS-SynRMs) are commonly diecasted by reducing pressure to ensure safe manufacturing. Hence, the shape of the squirrel-cage bars, including bubbles and blisters in the rotors of LS-SynRM, needs to be analyzed. In this paper, three different models are proposed to model the random bubble and blister phenomena by using 2-D finite-element analysis (FEA); their impacts on the flux paths and the change in exciting current of the squirrel-cage bars due to the unbalanced bubbles are thoroughly evaluated. Finally, consider that the bubbles' impacts are confirmed by manufacturing the prototype motor and performing the experiment. The results of FEA and the experiment clearly indicate that the impacts of additional bubbles and blisters need to be considered in the design of LS-SynRMs.</P>

Model Tests of Jacked-Pile Penetration into Sand Using Transparent Soil and Incremental Particle Image Velocimetry

Cong Liu,Xiao-Wei Tang,Huanwei Wei,Pengpeng Wang,Honghua Zhao 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.4

This paper presents a series of physical modelling tests of jacked-pile penetration into sand, combining the transparent soil and incremental reliability-guided particle image velocimetry, which provides a non-intrusively internal deformation measurement approach to monitor the internal movement of soil caused by jacked-pile penetration. The difference between the full-model test and the half-model test was analyzed quantitatively for the first time. This paper aims to provide some new insight into the penetration mechanisms of different shapes of pile tip. In addition, the phenomenon of meta-stable sand plug in the process of jacked-pile penetration was studied by means of the method of partial replacement with dyed particles. Experimental evidence has shown that the boundary and interaction effect causes the experimental phenomenon of the half-model test to be different from the true condition. The shape effect of pile tip on the governing penetration mechanisms was discussed, and the disturbance effect of different shapes of pile tip was evaluated and compared based on a large number of model tests and published literatures. The paper intuitively demonstrates that the different penetration mechanism of flat-ended pile and cone-ended pile is mainly due to the formation of the meta-stable sand plug beneath the pile tip.

Application of a C-Type Filter Based LCFL Output Filter to Shunt Active Power Filters

Cong Liu,Ke Dai,Kewei Duan,Yong Kang 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

This paper proposes and designs a new output filter called an LCFL filter for application to three phase three wire shunt active power filters (SAPF). This LCFL filter is derived from a traditional LCL filter by replacing its capacitor with a C-type filter, and then constructing an L-C-type Filter-L (LCFL) topology. The LCFL filter can provide better switching ripple attenuation capability than traditional passive damped LCL filters. The LC branch series resonant frequency of the LCFL filter is set at the switching frequency, which can bypass most of the switching harmonic current generated by a SAPF converter. As a result, the power losses in the damping resistor of the LCFL filter can be reduced when compared to traditional passive damped LCL filters. The principle and parameter design of the LCFL filter are presented in this paper, as well as a comparison to traditional passive damped LCL filters. Simulation and experimental results are presented to validate the theoretical analyses and effectiveness of the LCFL filter.

Design of Permanent Magnet-Assisted Synchronous Reluctance Motor for Maximized Back-EMF and Torque Ripple Reduction

Liu, Huai-Cong,Kim, In-Gun,Oh, Ye Jun,Lee, Ju,Go, Sung-Chul IEEE 2017 IEEE transactions on magnetics Vol.53 No.6

<P>This paper proposes the optimization of the shape and size of a ferrite magnet and the arrangements necessary to reduce torque ripple and maximize back electromotive force (B-EMF) in a permanent-magnet-assisted synchronous reluctance motor. First, four different models of general magnet arrangements were selected, and analysis using the finite-element method was performed under open circuit and load operations for each of the four models. Next, the relationship between the cogging torque and the torque ripple was analyzed, considering the segment saturation phenomenon. Then, based on the initial model, the design was optimized for maximum B-EMF and minimum torque ripple, and the total harmonic distortion was measured. Finally, the validity and superiority of the optimized design were confirmed by manufacturing a prototype motor and performing the experiment.</P>

Research on Crossing Tunnels' Seismic Response Characteristics

Cong Liu,Li-min Peng,Ming-feng Lei,Yu-feng Li 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

A large-scale shaking table test system and corresponding numerical model are designed to study the seismic characteristics of crossing tunnels. The calculated results are in good agreement with experimental data, both the results suggest that: Loading the El-Centro seismic wave, the maximum acceleration in upper tunnel’s crossing center section is located in the crown, the maximum strain is located in the haunch; meanwhile, the maximum acceleration and strain in underpass tunnel’s cross center section are both located in the crown. Affected by the underpass tunnel, at the side wall bottom of the upper tunnel, tests data reveal that the crossing center’s maximum acceleration is reduced for 30.9% and the strain was enlarged 170% than the normal section. Affected by the upper tunnel, at the haunch of the underpass tunnel, tests data reveal the crossing center’s maximum acceleration is enlarged by 10.0% and the strain is 27.2% reduced than the normal section.

Genome-wide locus-specific DNA methylation repatterning may facilitate rapid evolution of mercury resistance in rice

Cong Weixuan,Li Ning,Wang Jinbin,Kang Ying,Miao Yiling,Xu Chunming,Wang Ziqi,Liu Tongtong,Gong Lei,Liu Bao,Ou Xiufang 한국유전학회 2022 Genes & Genomics Vol.44 No.3

Background: Albeit a relatively stable epigenetic modification, DNA methylation in plants can be repatterned and play important roles in response to biotic and abiotic stresses. However, whether DNA methylation dynamics may contribute to cope with mercury (Hg) stress in plants remains to be fully investigated. Objective: To probe the potential roles of DNA methylation dynamics in coping with Hg stress in rice. Methods: Whole-genome bisulfite sequencing was used to profile the DNA methylation patterns of a rice Hg-resistant line (RHg) selected from a heterozygous mutant of the DNA methyltransferase 1 gene (OsMET1+/-), together with its Hg-sensitive wild-type plants of cv. Nipponbare (Nip) under both normal and Hg stress conditions. Results: Genome-wide locus-specific differential methylation regions (DMRs) were detected between RHg and Nip under normal condition, the predominant DMR patterns were CG hypo-DMRs, CHG hypo-DMRs and CHH hyper-DMRs. In both lines, more hyper- than hypo-DMRs were detected at all three sequence contexts (CG, CHG and CHH) under Hg stress relative to normal condition. Comparison of DNA methylation changes in the two lines under Hg stress indicates that RHg had a more dynamic methylome than the control (Nip). Original DMRs in RHg trended to transform to opposite status (from hyper- to hypo- or vice versa) under Hg stress condition. Gene ontology analysis revealed that Hg-resistance-related DMGs were enriched in diverse biological processes. Conclusions: Our results suggest genome-wide locus-specific DNA methylation repatterning can facilitate rapid acquisition of Hg resistance in rice.

The Roles of Money’s Pride and Surprise Tag on the Use of Money

Cong Liu,최낙환 한국마케팅학회 2015 ASIA MARKETING JOURNAL Vol.17 No.3

The present research examined the interesting but less attended effects of pride- and surprise-tagged money on consumers’ spending decisions. Focusing on the unexpected money received in their daily life, we explored recipient’s judgments and responses toward pride-tagged money versus surprise-tagged, and identified differences in types of recipient’s consumption and spending behaviors between the pride- tagged money and the surprise-tagged money. Consumers tend to use the money associated with pride (vs. surprise) to reward their invested effort; as a result, they were more likely to buy a personal gift. Moreover, in the context of self-gift, consumers with pride-tagged money have showed a bigger positive difference between the intent to buy individual self-expressive products and the intent to buy social self-expressive products than those with surprise-tagged money. And the receipt of pride-tagged money activates motivation to express one’s individual self. Consumers who have received a sum of extra money tend to add the money into the current spendable income account and broaden the array of product category. And consumers with high arousal level of surprise triggered by receiving a sum of unpredictable money because of good luck show a smaller difference between the intent to buy individual self-expressive product and the intent to buy social self-expressive product than those with low level arousal in pride. Therefore, marketers should advertise their products in the respects of individual self-expression when their customers have pride-tagged money, and should advertise their products in the respects of social self-identity when they have surprise-tagged money by winning a large sum of unpredicted money like lottery winning.