• Title/Summary/Keyword: SEI formation

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A LiPF6-LiFSI Blended-Salt Electrolyte System for Improved Electrochemical Performance of Anode-Free Batteries

  • Choi, Haeyoung;Bae, YeoJi;Lee, Sang-Min;Ha, Yoon-Cheol;Shin, Heon-Cheol;Kim, Byung Gon
    • Journal of Electrochemical Science and Technology
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    • v.13 no.1
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    • pp.78-89
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    • 2022
  • ANODE-free Li-metal batteries (AFLMBs) operating with Li of cathode material have attracted enormous attention due to their exceptional energy density originating from anode-free structure in the confined cell volume. However, uncontrolled dendritic growth of lithium on a copper current collector can limit its practical application as it causes fatal issues for stable cycling such as dead Li formation, unstable solid electrolyte interphase, electrolyte exhaustion, and internal short-circuit. To overcome this limitation, here, we report a novel dual-salt electrolyte comprising of 0.2 M LiPF6 + 3.8 M lithium bis(fluorosulfonyl)imide in a carbonate/ester co-solvent with 5 wt% fluoroethylene carbonate, 2 wt% vinylene carbonate, and 0.2 wt% LiNO3 additives. Because the dual-salt electrolyte facilitates uniform/dense Li deposition on the current collector and can form robust/ionic conductive LiF-based SEI layer on the deposited Li, a Li/Li symmetrical cell exhibits improved cycling performance and low polarization for over 200 h operation. Furthermore, the anode-free LiFePO4/Cu cells in the carbonate electrolyte shows significantly enhanced cycling stability compared to the counterparts consisting of different salt ratios. This study shows an importance of electrolyte design guiding uniform Li deposition and forming stable SEI layer for AFLMBs.

Hydroalcoholic Extract of Scrophularia Striata Attenuates Hypertrophic Scar, Suppresses Collagen Synthesis, and Stimulates MMP2 and 9 Gene Expression in Rabbit Ear Model

  • Zarei, Hatam;Tamri, Pari;Asl, Sara Soleimani;Soleimani, Meysam;Moradkhani, Shirin
    • Journal of Pharmacopuncture
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    • v.25 no.3
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    • pp.258-267
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    • 2022
  • Objectives: Hypertrophic scars (HSs) are caused by abnormal wound healing. To date, no standard treatment has been made available for HSs. Scrophularia striata has been reported to accelerate wound healing and has the potential to prevent HS formation. In this study, we investigated the anti-scarring effects of S. striata extract (SSE) in a rabbit ear model of scarring. Methods: In this study, New Zealand white rabbit (weight: 2.3-2.5 kg) were used. In the prevention phase of the study, three test groups received 5%, 10%, and 15% ointments of SSE in the Eucerin base, the fourth group received Eucerin, and the fifth group received no treatment. The samples were obtained on day 35 after wounding. In the treatment phase of the study, the test groups received an intralesional injection of SSE (5%, 10%, and 15%), the fourth group received an intralesional injection of triamcinolone, the fifth group received a solvent (injection vehicle), and the sixth group received no treatment. To evaluate the anti-scarring effects of SSE, the scar elevation index (SEI), epidermis thickness index (ETI), collagen deposition, and MMP2 and MMP9 gene expression were evaluated. Results: A significant reduction in SEI, ETI, and collagen deposition was noted in animals treated with SSE compared with the control groups. In addition, topical SSE stimulated MMP2 and MMP9 gene expression. Conclusion: The findings of this study demonstrate the potential for SSE in the prevention and treatment of HS. SSE could be prepared as an appropriate formulation to treat wounds and prevent abnormal scarring.

A Study on the Formation of Urban Squatter in Korea and their Housing Culture from Socio-historical Point of View (사회사적 관점에서 본 우리나라 도시빈민의 형성배경과 주거문화 - 개항 이후 토막민촌부터 한구전쟁 직후 판자촌까지 -)

  • Jun, Nam-Il;Yang, Se-Hwa;Hong, Hyung-Ock;Sohn, Sei-Kwan;Kim, Myo-Jung
    • Journal of the Korean housing association
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    • v.18 no.3
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    • pp.9-18
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    • 2007
  • The purpose of this study was to provide the basic information about the formation background of urban squatter and their housing state in Korea. This study was progressed on the basis of socio-historical point of view from the opening of a port to the after the Korean War. In that sense, this study considered meaning of housing for urban squatter in the Korean housing history. For this study, the formation background of the urban squatter was divided into three periods. The first period was after the opening of a port (1876-1910) when the inflow of Japanese and their plundering from Korea started. The second was Japanese occupation period (1910-1945) which contributed to increase the number of Tomak (mud hut) and made the Tomak-min's village. The third period was Korean war & postwar years (1945-1953). This period was divided into three parts again; after the Korean independence (1945-1950), during the Korean War (1950-1953), and after the Korean War (1953-). The urban squatter was settled in the national land and the public land in each period and experienced the severe housing shortage. The government of the time could not protect the urban squatter from the special national states such as the Japanese rule and the Korean War.

Mechanism of Surface Film Formation on Graphite Negative Electrodes and Its Correlation with Electrolyte in Lithium Secondary Batteries (리튬 이차전지의 흑연 음극 표면피막 생성기구와 전해질과의 상관성)

  • Jeong, Soon-Ki
    • Journal of the Korean Electrochemical Society
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    • v.13 no.1
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    • pp.19-33
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    • 2010
  • The surface film, which is formed on graphite negative electrodes during the initial charging, is a key component in lithium secondary batteries. The battery reactions are strongly affected by the nature of the surface film. It is thus very important to understand the physicochemical properties of the surface film. On the other hand, the surface film formation is a very complicated interfacial phenomenon occurring at the graphite/electrolyte interface. In studies on electrode surfaces in lithium secondary batteries, in-situ experimental techniques are very important because the surface film is highly reactive and unstable in the air. In this respect electrochemical atomic force microscopy (ECAFM) is a useful tool for direct visualizing electrode/solution interfaces at which various electrochemical reactions occur under potential control. In the present review, mechanism of surface film formation and its correlation with electrolyte are summarized on the basis of in-situ ECAFM studies for understanding of the nature of the surface film on graphite negative electrodes.

Effect of PHA and conditioned medium on blastogenesis and rosette formation of bovine circulating blood lymphocytes (PHA 및 conditioned medium 이 소의 순환혈액 림프구의 유약화와 rosette 형성에 미치는 영향)

  • Kang, Sei-woong;Yoon, Chang-yong;Song, Hee-jong
    • Korean Journal of Veterinary Research
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    • v.34 no.2
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    • pp.301-306
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    • 1994
  • This study was planned to estimate the activity of bovine circulating blood lymphocytes using phytohemagglutinin-M(PHA) known as T cell mitogen. Bovine circulating blood mononuclear cells(MNCs) was separated, and cultured with or without macrophage($PHA^+/M{\phi}^+$ or $PHA^+/M{\phi}^-$) in conditioned medium which stimulated with various concentration of PHA(0, 5, 10, 15 and $20{\mu}g/ml$ in medium), and then investigated the blastogenic response and rosette formation of lymphocytes. Blastogenic rate(BR) was especially increased in PHA concentration(10 and $15{\mu}g/ml$) of $PHA^+/M{\phi}^+$ group and their BR were $41.5{\pm}6.8%$ and $44.4{\pm}8.9%$, respectively and BR in PHA concentration(15 and $20{\mu}g/ml$) of $PHA^+/M{\phi}^-$ group was $32.8{\pm}6.2%$ and $31.4{\pm}4.6%$, respectively. BR of lymphocytes was more increased in $PHA^+/M{\phi}^+$ than $PHA^+/M{\phi}^-$ group when these cells were stimulated by PHA. Rosette forming rate(RFR) of lymphocytes to SRBC highly increased when SRBC was treated with AET and/or dextran, respectively. On the orther hand, RFR significantly increased more in $PHA^+/M{\phi}^+$ and $PHA^+/M{\phi}^-$ group than in control group, but when compared with two groups, statistical significancy was recognized only in PHA concentration($15{\mu}g/ml$, p<0.026) of $PHA^+/M{\phi}^+$ group.

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Radition Effect on Colony Formation of HeLa.S3(SC) Cell Line (HeLa.S3(SC) 세포계의 집락형성에 미치는 방사선의 효과)

  • Shin, Sei-One;Kim, Sung-Kyu;Kim, Myung-Se
    • Journal of Yeungnam Medical Science
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    • v.10 no.1
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    • pp.212-217
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    • 1993
  • Since discovery of X-rays, radiotherapy has evolved into one of the most scientific branches of medicine and has established its role as the primary line or the secondary line of attack, after surgery, in the treatment of malignant cancers. Nowadays its importance is illustrated by the fact that as many as 70 per cent of all pastients with cancer will receive radiation therapy at sometime during their disease process. Biologic effects of X-rays began to be apparant soon after the discovery by Roentgen in 1895. In clinical radiotherapy, the biologic endpoint of most importance is loss of cellular reproductive ability or clonogenicity. One of the commonest ways to assess cell survival is to use an in vitro plating assay. We analyzed radiation effect on colony formation of HaLa.S3(SC) cell line and obtained results are as follows: The plating efficiency is 0.464. The shape of cell survival curve is similar to multi-target plus single hit component model. Estimated values of Do, Dq, and extrapolation number are 150 cGy, 80 cGy and 1.7 respectively. We reported these experimental data with review of literature.

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A Study on the Formation of Working-Class Residential Areas md the Transformation of Housing Types of Firenze, Italy (이탈리아 피렌체의 서민주거지역의 형성과 주거형식의 변화에 관한 연구)

  • Sohn, Sei-Kwan
    • Journal of architectural history
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    • v.13 no.2 s.38
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    • pp.21-38
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    • 2004
  • This study provides a descriptive and analytical account of major aspects of urban development and transformation of housing types of Italian Firenze from the 13th century to the 19th century. It is a typo-morphological depiction of urban spatial structure of the extraordinary city, Firenze, the center of Italian Renaissance. And this study has proceeded on the assumption that the evolving form of the urban structure and housing types cannot be understood without reference to the larger context of political, economic, and social life. Based on these backgrounds, the purpose of this study is threefold: to provide a comprehensive discussion of general characteristics of urban spatial structure of Firenze, and to explain the process of formation of working-class neighborhoods by constructing new city wall in later 13th century, and to discuss transformation of housing types of the working-class neighborhood with understanding the mechanism of existence of housing in the newly formed residential neighborhoods. The development of residential neighborhoods was pursued by 'planned' manner through forming square-shaped blocks, and characterized by the subdivision of larger properties into standardized building lots for the construction of houses. On the bases of documentary evidences, several ecclesiastical institutions are identified as the agents of a distinctive type of development. While the institutions did the major role for developing lands, the construction of houses was done by small scale construction agents with moderate amount of properties. The major housing type of working-class neighborhoods of Firenze has been the 'casa a schiera' characterized by the form of narrow front and long depth. The type was generalized by the newly formed middle and working-class of Firenze which grew their body very rapidly, Even though the type assumed very uniform in its fen there were many variations. And through passing time, the casa a schiera developed to be multi-family housing, and the level of variation became deepen. Eventually, transformation of housing type of Firenze was ended by appearance of the 'casa in linea', which was very similar to modern apartment in its spatial organization.

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Molecular Analysis of Geminigirus ORFs on Symptom Development

  • Park, Eulyong;Hyunsik Hwang;Lee, Sukchan
    • The Plant Pathology Journal
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    • v.15 no.1
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    • pp.38-43
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    • 1999
  • Mutants of the monopartite geminivirus beet curly top virus (BCTV) have been screened for infectivity, systemic movement, replication and symptom development in Arabidopsis thaliana. As known by coding for coat protein, R1 mutant was not infectious and did not move systemically. R2, R3 and L2/L3 mutants produced milder symptoms compared to wild type BCTV but the infectivity was reduced by 40% to 60%. R2 ORF is thought to be involved in the regulation of ssDNA and dsDNA accumulation because only dsDNA was accumulated on R2-infected organs. Disruption of ORF L4 resulted in reduced infections, but the viral DNA was accumulated in infected organs from roots to shoot tips as much as wild type BCTV on Sei-O. In addition, 4 mutants did not produce callus-like tissues on infected organs, suggesting that L4 ORF may play a role in the induction of host cell divisions by virus infection. This result was supported by the patterns of mRNA expression and promoter analysis of the cell cycle marker gene, cycl, on Arabidopsis. cycl mRNA was accumulated on symptomatic organs by wild type BCTV infections but not by L4 mutant. We conclude that the BCTV L4 ORF is essential for symptom developments, specially callus-like formation on infected organs.

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Tansport Rate of Chromium ion from Waste Water through the Liquid Surfactant Membrane Containing Carrier (운반체 함침 유화액막에 의한 폐수중 크롬(VI)의 이동속도)

  • Woo, In-Sung;Kim, Kyoung-Ho;Lee, Sang-Jin;Kang, An-Soo;Choi, Sei-Young
    • Elastomers and Composites
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    • v.23 no.1
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    • pp.11-17
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    • 1988
  • The transport of chromium(VI) ion from waste water through the liquid surfactant membrane containing tri-n-octylamine as a carrier, was analyzed by a slab model and was investigated through experiments. For the experiment of membrane stability, concentrations of surfactant and liquid paraffin oil were analyzed. Extraction experiments were carried out to observe the effect of system variables, such as concentrations of carrier, and initial chromium(VI) ion in external aqueous phase at $25^{\circ}C$. It is concluded that the most stable formation of liquid membrane emulsion was obtained when surfactant concentration is above 3 wt.% and liquid paraffin oil concentration is 50 vol.%. The theoretical equation on the transport of chromium(VI) ion agreed well with the experimental results.

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Microwave Cure of Rubber Compound for Tire Tread (타이어 트레드용 고무배합물의 마이크로파 가황)

  • Han, Shin;Kang, Yong-Gu;Sohn, Bong-Young;Oh, Sei-Chul;Park, Chan-Young
    • Journal of the Korean Society of Industry Convergence
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    • v.2 no.1
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    • pp.69-75
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    • 1999
  • Intending to develop a new rubber curing process using only microwave, the both the characteristics of cure and the mechanical properties of rubbers for the tire tread, for which a green styrene-butadiene compounds had been cured with 2.45 GHz microwave, have been compared with those of the custom thermal cured rubber. The unintentional hot spot formation in the compound during the microwave curing has not found where the compound has a microwave absorbing ceramic powders in 4.18 weight percents and the supplying voltage has been adjusted to 90 volts. The new microwave process accomplished preheating to 418K in a quarter of the thermal cure time. The average tensile strength of the microwave-cured rubber indicating $190kg/cm^3$ was compatible to that of the thermal cure. In conclusion, the new microwave cure had approved to be applicable in a commercial plant.

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