http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Assessment of green approaches for the synthesis of physically crosslinked lignin hydrogels
Amaia Morales,Jalel Labidi,Patricia Gullón 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-
Lignin is an excellent candidate to be used as a starting material for hydrogel synthesis due to its highlyfunctional character. The exhaustible character of the fossil resources linked to the increase of plasticresidues in the environment encourages an intensive research on biorenewable and biodegradablepolymers to synthesize new materials. Taking into account this current scenario, this work searches fornew green routes to elaborate physical hydrogels with excellent capacity of swelling and suitableconsistency. To this end, lignin and poly(vinyl alcohol) were blended in different proportions following athree-level-two-factorial design and using six different routes of crosslinking and drying for each set ofexperiments. The hydrogels formed under the optimal conditions were characterized by FTIR, SEM, XRD,DSC and TGA and their mechanical properties were also evaluated by compression tests. The selectedoptimum synthesis routes enabled the obtaining of physically crosslinked hydrogels with up to 800%water retention ability. FTIR spectra confirmed the interactions between lignin and PVA showing shiftsand modifications on the characteristic bands of the raw polymers. Compression tests showed that all thehydrogels kept complete integrity even compressing them up to an 80% of their initial thickness.
GULLE, ESRA,ULUSU, UGUR The Korean Society for Computational and Applied M 2022 Journal of applied mathematics & informatics Vol.40 No.1-2
In this paper, for double set sequences, as a new approach to the notion of Wijsman asymptotical lacunary statistical equivalence of order 𝜂, we introduce new concepts which are called Wijsman asymptotical ${\mathcal{I}}_2$-lacunary statistical equivalence of order 𝜂 and Wijsman asymptotical strong ${\mathcal{I}}_2$-lacunary equivalence of order 𝜂 where 0 < 𝜂 ≤ 1. Also, some properties of these new concepts are investigated, and the existence of some relations between these and some previously studied asymptotical equivalence concepts for double set sequences is examined.
DOUBLE WIJSMAN LACUNARY STATISTICAL CONVERGENCE OF ORDER 𝛼
GULLE, ESRA,ULUSU, UGUR The Korean Society for Computational and Applied M 2021 Journal of applied mathematics & informatics Vol.39 No.3
In this paper, we introduce the concepts of Wijsman strongly p-lacunary summability of order 𝛼, Wijsman lacunary statistical convergence of order 𝛼 and Hausdorff lacunary statistical convergence of order 𝛼 for double set sequences. Also, we investigate some properties of these new concepts and examine the existence of some relationships between them. Furthermore, we study the relationships between these new concepts and some concepts in the literature.
The Dark Side of Internal Capital Allocation : The Case of Korean Chaebols
Dong Gull Lee,Keonbeom Lee 서울대학교 경제연구소 2002 Seoul journal of economics Vol.15 No.2
In this paper, we first briefly survey the theories of internal capital markets and then provide an empirical analysis of the efficiency of internal capital allocations among the chaebols in Korea. Our analysis of equity investment flow among the subsidiaries of the top 30 chaebols from 1997 to 2001 suggests that the chaebols' inter-affiliate equity investment during this period cannot be justified by sound economic rationale, and reveals the dark side of internal capital allocation. Furthermore, we find that a strong positive relationship does not exist between equity investment and real investment. In conclusion, the internal capital allocations among the chaebols have continued to be inefficient and therefore, the argument to loosen restrictions on inter-affiliate equity investments to increase real investment cannot be justified.
Byeong-Gull Kim,김경수,김순배,정운관,조재환,박용순 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.11
The goal of this study is to determine which imaging location on phase contrast magnetic resonance imaging (PC MRI) best correlates with echocardiography to enable the severity of aortic regurgitation to be accurately evaluated by using PC MRI. The subjects were 34 patients with aortic regurgitation confirmed by echocardiography and cardiac MRI. Two velocity distribution images were obtained by positioning image planes above and below the aortic valve in the PC MRI. Using the acquired images, regurgitation fractions were calculated by calculating the average forward and reverse blood flows. The severity of aortic regurgitation was then evaluated and compared with the severity as determined by using echocardiography. When image planes were positioned above the aortic valve, the regurgitation fraction obtained by using PC MRI was 44.5 ± 18.7%, and when planes were positioned below the valve, the regurgitation fraction was 34.8 ± 15.9%. Regarding agreement with echocardiographic findings, concurrence was shown to be 50% when image planes sections were positioned above the valve and 85.3% when they were positioned below the valve. The present study shows that if image planes are positioned below the valve rather than above the valve, provides as accurate evaluation of the severity of aortic regurgitation.