Structure and Performances of xLiFePO4/C·(1 − x)Li3V2(PO4)3/C Cathode for Lithium-Ion Batteries by Using Poly(vinyl alcohol) as Carbon Source

Chang-ling Fan,Wei-hua Zhang,Tao-tao Zeng,Ling-fang Li,Xiang Zhang,Shao-chang Han 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.11

Poly(vinyl alcohol), whose pyrolysis carbon possesses high conductivity of 8.88 × 10−1 S/cm, was used to synthesize xLiFePO4/C·(1 − x)Li3V2(PO4)3/C cathode. It was characterized by X-ray diffraction, scanning electron microscopy, conductivity, cyclic voltammetry, and galvanostatic charge and discharge experiments. Results show that LiFePO4/C and Li3V2(PO4)3/C coexists in the cathode. The particles sizes of 0.75LiFePO4/C·0.25Li3V2(PO4)3/C (x = 0.75) are much smaller than 100 nm due to the role of poly(vinyl alcohol). Its conductivity is 8.79 × 10−2 S/cm. The oxidative and reductive peaks in cyclic voltammetry are sharp and symmetrical. Their low potential gaps indicate that the extractions and insertions of lithium ion possess excellent reversibility. Its discharge capacities at 1 and 5 C are 141.1 and 100.1 mAh/g. The more Li3V2(PO4)3/C in cathode results in the deterioration of electrochemical performances due to its low theoretical capacity. It is concluded that poly(vinyl alcohol) is an effective carbon source in the preparation of xLiFePO4/C·(1 − x)Li3V2(PO4)3/C composite cathode with excellent performances.

Electrolyte effect on the catalytic performance of Ni-based catalysts for direct internal reforming molten carbonate fuel cell

Li, Z.,Devianto, H.,Yoon, S.P.,Han, J.,Lim, T.H.,Lee, H.I. Pergamon Press ; Elsevier Science Ltd 2010 International journal of hydrogen energy Vol.35 No.23

An active and tolerant Ni-based catalyst for methane steam reforming in direct internal reforming molten carbonate fuel cells (DIR-MCFCs) was developed. Deactivation of reforming catalysts by alkali metals from the electrolyte composed of Li<SUB>2</SUB>CO<SUB>3</SUB> and K<SUB>2</SUB>CO<SUB>3</SUB> is one of the major obstacles to be overcome in commercialization of DIR-MCFCs. Newly developed Ni/MgSiO<SUB>3</SUB> and Ni/Mg<SUB>2</SUB>SiO<SUB>4</SUB> reforming catalysts show activities of ca. 80% methane conversion. Subsequent to electrolyte addition to the catalyst, however, the activity of Ni/Mg<SUB>2</SUB>SiO<SUB>4</SUB> decreases to ca. 50% of its initial value, whereas Ni/MgSiO<SUB>3</SUB> catalyst retains its initial activity. Results obtained from temperature-programmed reduction and X-ray photoelectron spectroscopy identify unreduced Ni<SUP>3+</SUP> as a decisive factor in keeping catalytic activity from the electrolyte.

Modeling, Preparation, and Elemental Doping of Li₇La₃Zr₂O₁₂ Garnet-Type Solid Electrolytes: A Review

Cao, Shiyu,Song, Shangbin,Xiang, Xing,Hu, Qing,Zhang, Chi,Xia, Ziwen,Xu, Yinghui,Zha, Wenping,Li, Junyang,Gonzale, Paulina Mercedes,Han, Young-Hwan,Chen, Fei The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.2

Recently, all-solid-state batteries (ASSBs) have attracted increasing interest owing to their higher energy density and safety. As the core material of ASSBs, the characteristics of the solid electrolyte largely determine the performance of the battery. Thus far, a variety of inorganic solid electrolytes have been studied, including the NASICON-type, LISICON-type, perovskite-type, garnet-type, glassy solid electrolyte, and so on. The garnet Li₇La₃Zr₂O₁₂ (LLZO) solid electrolyte is one of the most promising candidates because of its excellent comprehensively electrochemical performance. Both, experiments and theoretical calculations, show that cubic LLZO has high room-temperature ionic conductivity and good chemical stability while contacting with the lithium anode and most of the cathode materials. In this paper, the crystal structure, Li-ion transport mechanism, preparation method, and element doping of LLZO are introduced in detail based on the research progress in recent years. Then, the development prospects and challenges of LLZO as applied to ASSBs are discussed.

Study on Multi-Field Coupled Evolution Mechanism of Laser Irradiated 40Cr Steel Quenching Process Based on Phase Change Induced Plasticity

Chang Li,Hexin Gao,Xinxue Chen,Zhaotai Liu,Xing Han 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

40Cr is essential to steel for the manufacture of hardened gears, and optimizing its laser quenching process will be of greatsignificance for gear wear and life extension. However, the complete reliance on the experimental trial-and-error approachdoes not effectively reveal the mechanism of the evolution of the laser quenching process in disk laser. Numerical simulationprovides an effective way to obtain the transient evolution of the laser quenching process. In this paper, the temperaturechanges physical parameters of the quenched material are calculated based on the CALPHAD method. Establish a thermoelastic–plastic multi-field coupling model for the laser hardening process of the disk laser 40Cr gear steel. Perform thenumerical calculations on the transient temperature, martensite phase fraction, and the transformation-induced plasticitystress evolution of the 40Cr laser hardening process. Focus on the mechanism of the mutual coupling between phase changebehavior and plastic strain. Calculations show that there is heat accumulation during quenching, with a peak temperatureof 1448 K. Plastic stress has a “hump” distribution, with a peak value of 834 MPa, which is 1.25 mm from the center ofthe focal point. The experimental analyses of the 40Cr gear steel quenching microstructure and hardness distribution stateby the Axioskop2 scanning electron microscope, the KEYENCE VH-Z100R super depth of field 3D microscope, and theQ10M microhardness tester reveal the mechanical behavior of the material and the phase hardening law during the quenchingprocess. That provided an essential theoretical basis for effective prediction on quenching residual stress and optimizingindustrial production parameters.

CO2 Adsorption on the B12N12 Nanocage Encapsulated with Alkali Metals: A Density Functional Study

Haiyan Zhu,Qiyan Zhang,Qinfu Zhao,He Zhao,Yifan Feng,Bingbing Suo,Huixian Han,Qi Song,Yawei Li,Wenli Zou,Haiyan Zhu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.3

Density functional theory (DFT) calculations have been carried out to study the capacity of the B12N12 nanocage encapsulated with alkali metals (Li, Na, K) for the CO2 adsorption and activation. It is found that after encapsulating alkali metals, the alkali metal atoms are closer to one side of clusters instead of exactly lying at the center, and a considerable charge transfers from the inner alkali metal atoms to the B12N12 cage. Besides, the HOMO–LUMO gap (HLG) values of Li@B12N12, Na@B12N12 and K@B12N12 are decreased to about 6 eV, being much smaller than that of the pristine B12N12. Although the geometry structure parameters and the energy differences of M06-2X are slightly different from the ones of ωB97X-D, some identical results of two kinds of functional can be obtained. CO2 can be adsorbed chemically and physically on majority bonds of all the clusters, except for some bonds with large change in bond length and bond indices. The encapsulation of alkali-metal atoms may enhance the physical and chemical adsorption of CO2 on the surface of the clusters, in which Na@B12N12 and K@B12N12 are the most powerful physical and chemical adsorbent for CO2, respectively.

Weak Connection Edges Independent Discriminant of Rapid Spanning Tree Recommendation of Social Network Community

Cao Ke-xing,Li Zhao-xing,Li Xin,Lv Zhi-han4 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.3

Aiming at the problem of low accuracy and high computational complexity of the traditional social network community recommendation algorithm, a rapid spanning tree detection algorithm is proposed to independently discriminate social network community with the weak connected edge, in order to improve the accuracy of community recommendation and reduce the complexity of algorithm. Firstly, according to the characteristics of social network community recommendation, the maximum spanning tree algorithm is proposed, which is based on the edge weight distribution node similarity, to realize the effective detection of social network community. Secondly, for the proposed algorithm having the problems of repeated adding and deleting of weakly connected edges and the waste of computing resources, a rapid spanning tree detection algorithm based on the independent discrimination of weakly connected edge is proposed so as to further improve the calculation efficiency of the algorithm. Lastly, the effectiveness of the proposed algorithm is verified by comparing the experimental results in the standard test database.

각형강관 가새부재의 폭두께비에 따른 거동 평가

천성욱,한상환,이리형 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

Braced frames are a popular framing system for resisting to seismic loads in buildings because braced frame can provide large lateral stiffness and strength than moment frames. Hollow Square Section(HSS) members are one of the most efficient sections of compression members and bracing members. In this experimental study. Specimens were designed according to the AISC LRFD manual. The major parameter of these specimens is a width-thickness ratio. In this study three specimens were made for each test parameters to account for the variability of test results. The nine full-scale test specimens were tested using a quasi-static cyclic loading. This study modified the standard loading history in SAC to make it adequate for a bracing member test.

라미부딘 내성 만성 B형 간염 환자에서의 아데포비어의 치료 효과

이지숙,장리라,이상욱,한병훈,윤병철 고신대학교의과대학 2008 고신대학교 의과대학 학술지 Vol.23 No.2

Backgrounds/Aims : Adefovir dipivoxil(ADV) has been shown to be effective against lamivudine resistant strain of hepatitis B virus. But continuation of lamivudine therapy or switching to Adefovir dipivoxil in patients with viral breakthrough after long term lamivudine therapy are controversial. To find efficacy of adefovir dipivoxil, we retrospectively assessed clinical course after lamivudine resistance in patients who changed adefovir dipivoxil and continued lamivudine therapy. Methods : 58 patients with lamivudine resistant HBV mutants after at least 6 months of lamivudine treatment were included in this study. 24 of the 58 patients were treated with ADV and rest of them were continued the lamivudine therapy after lamivudine resistance. The continuous lamivudine treatment group (n=34) was divided into two groups according to ALT count (ALT≧40, n=19 vs ALT<40, n=16) The clinical course and the biochemical and virological response of the switching adefovir group were compared with those of continuing lamivudine group. HBV genotypes and YMDD mutation site was anaylzed by TRUGENE HBV Genotyping. Results : At twelve months, the levels of median serum HBV DNA and ALT was decreased and albumin was improved significantly(P<0.01) in adefovir switching group compared with lamivudine sustained group, especially ALT was elevated more than 40. There is no significant differences between adefovir switching group and lamivudine sustained group (ALT<40, n=15). This study showed that adefovir dipivoxil reduces HBV replication and improves not only biochemical markers of disease activity, but also liver function. HBV genotypes of 58 patients were all C and rtM204I/V mutant was the most common. Conclusion : This study provides an evidence that adefovir dipivoxil can be effective in the treatment of lamivudine-resistant HBV mutants, especially ALT elevated.

Effect of inorganic mesoporous carriers on 1-palmitoyl-2-linoleoyl-3-acetyl-<i>rac</i>-glycerol-loaded solid self-emulsifying drug delivery system: Physicochemical characterization and bioavailability in rats

Kim, Dong Shik,Yang, Eun Su,Yong, Chul Soon,Youn, Yu Seok,Oh, Kyung Taek,Li, Dong Xun,Kim, Jong Oh,Jin, Sung Giu,Choi, Han-Gon Elsevier 2017 Colloids and Surfaces B Vol.160 No.-

<P><B>Abstract</B></P> <P>The purpose of this study was to assess the impact of inorganic mesoporous carriers on the physicochemical properties and oral bioavailability of 1-palmitoyl-2-linoleoyl-3-acetyl-<I>rac</I>-glycerol (PLAG)-loaded solid self-emulsifying drug delivery system (solid SEDDS). Numerous PLAG-loaded solid SEDDS formulations were prepared by spray drying technique with sodium laurylsulfate (SLS), butylated hydroxyanisole (BHA) and inorganic mesoporous materials as a surfactant, antioxidant and solid carrier, respectively. The mesoporous materials, such as calcium silicate, silicon dioxide and magnesium aluminosilicate were used as the solid carriers. Their physicochemical properties, solubility, dissolution and pharmacokinetic studies in rats were performed compared with drug alone. Three solid SEDDSs composed of PLAG/BHA/SLS/mesopous carrier at the weight ratio of 1:0.0002:0.25:0.5 resulted in a small emulsion droplet and excellent drug loading efficiency. The solid SEDDS formulations prepared with calcium silicate and silicon dioxide showed a rough-surfaced irregular shape and rough-surfaced spheres, respectively. Magnesium aluminosilicate generated a sticky powder, due to its relatively low specific surface area, resulting in insufficient adsorption of PLAG. These solid SEDDSs improved the solubility, dissolution and oral bioavailability of PLAG. Ultimately, the solid SEDDS prepared with silicon dioxide resulted in the best drug loading efficiency, shape, solubility, dissolution and oral bioavailability due to its great specific surface area. Therefore, mesoporous carriers with different specific surface areas markedly influenced the physicochemical properties, solubility, dissolution and oral bioavailability of PLAG-loaded solid SEDDS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of mesoporous carriers on PLGA-loaded solid SEDDS were assessed. </LI> <LI> Numerous PLGA-loaded solid SNEDDS were prepared using spray drying technique. </LI> <LI> Calcium silicate, silicon dioxide and magnesium aluminosilicate were used as the mesoporous carriers. </LI> <LI> The solid SEDDS prepared with silicon dioxide gave most excellent loading efficiency and bioavailability. </LI> <LI> Mesoporous carriers markedly influenced the physicochemical properties and bioavailability of solid SEDDS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A clustering based routing algorithm in IoT aware Wireless Mesh Networks

Li, Jilong,Silva, Bhagya Nathali,Diyan, Muhammad,Cao, Zhenbo,Han, Kijun Elsevier 2018 Sustainable cities and society Vol.40 No.-

<P><B>Abstract</B></P> <P>The Internet of Things (IoT) notion enables embedded devices to connect and share data through IP or the web. Interference routing metric and adaptive load balancing have gained much attention as the key challenges to overcome in IoT based wireless mesh networks (WMN) with the increase in wireless service performance. Moreover, IoT over WMN severely affected by network traffic caused by enormous data generation by a large number of users. Hence, we have proposed a clustering based routing algorithm considering an interference and load balancing routing metric that focuses on minimizing the existing issues of networks. In this study, we propose a scheme that reduces the end-to-end delay but also gives full consideration to both the quality on the entire route to the destination and to the expected lifetime of nodes with bottlenecks from heaped traffic in IoT. Simultaneously, it utilizes mesh station channel interference and queue information appropriately to address the identified challenges. The simulations results show that the proposed scheme performed superior to the existing routing metrics present in the current literature for similar purposes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Our system achieve optimal network throughput. </LI> <LI> In IoT over WMN environment, a Load Balancing and Interference Delay Aware routing algorithm is used to avoid network traffic jam. </LI> <LI> The proposed scheme efficiently utilizes the available mesh station queue information and the number of mesh nodes that suffers from channel interference in the available path. This increases the network energy efficiency by managing the interference delay. </LI> </UL> </P>