Search

Owing to the proliferation of people in cities worldwide, the size of urban green areas has decreased along with biodiversity. Suwon City, a highly populated area adjacent to Seoul, the capital of the Republic of Korea, and the subject of this study, has been making significant efforts to prevent such a decrease in biodiversity. In this study, we aim to develop a suitable scenario for roof greening in Suwon City, analyze how the efficiency of increasing the suitable habitat area of the Paridae bird changes with the scenario, and propose the most efficient roof greening plan. For the development and application of this plan, public, commercial, and residential buildings were selected as target spaces to which roof greening was applied. Then, the appropriate roof greening area was determined (400000 m2, which is 0.712% of the area of Suwon) with reference to the Roof Greening Promotion Plan of Seoul. Subsequently, roof greening types were classified into low, medium, and high management based on the cases of roof greening. We found that the increase in the habitat area of Paridae depended on the types of roof greening and construction building. The buildings with the highest efficiency of increasing the habitat area in Suwon City (an increase of 1197.5%) were all commercial buildings except for those with low management, while the buildings with the lowest efficiency (115%) were public buildings. The information on the increases in the habitat area of Paridae and the cost of roof greening per area (m2) for the three types of building can be used to establish suitable green roofs that will promote urban biodiversity. [ABSTRACT FROM AUTHOR]

Many countries worldwide are experiencing natural disasters that have not been experienced in the past owing to abnormal weather caused by climate change, resulting in considerable economic damage and human casualties. Global warming, which is the increase in Earth's temperature due to the greenhouse effect primarily caused by carbon emissions to the atmosphere, is considered as the main cause. Thus, various international agreements are being promoted to reduce carbon emissions. The Republic of Korea (ROK) is also abiding with these international agreements and enacting and enforcing related and fundamental laws in response to international trends. To reduce carbon emissions, the management and composition of existing and new carbon sinks are being highlighted, and urban park green areas play an essential role as existing carbon sinks. Research is needed to understand how urban parks can contribute to carbon neutrality and the importance of local government units that manage these urban parks. Therefore, in this study, we aim to quantitatively analyze the current status of CO2 storage and absorption of trees in urban parks on the basis of tree survey data obtained from representative urban parks located in Daejeon-si, the target site of this study. The methodology for analyzing the amounts of CO2 storage and absorption was applied in two ways by referring to previous studies, and the reliability of the results was reviewed to confirm the appropriate methodology. In addition, on the basis of the amounts of CO2 storage and absorption per unit area of the park derived through analysis, the amounts of CO2 storage and absorption of trees in urban parks for the entire city of Daejeon-si were estimated. As a result of this study, the amounts of CO2 storage and absorption of 1931 ha of 557 established parks, parks under construction, and unconstructed parks in Daejeon-si were calculated as 492096 tCO2/ha and 18498 tCO2/ha/y, respectively. The storage and absorption of CO2 per unit area in this study are expected to be used as data for climate change response, carbon neutrality measures, and decision-making. [ABSTRACT FROM AUTHOR]

A new type of low-k dielectric material, poly(tridecafluoro1,1,2,2,tetrahydrooctyl-co-phenylsilsesquioxane) (PFCPSQ) was synthesized by hydrolysis and condensation reaction of trimethoxysilyl monomers in the presence of a base catalyst in H2O/THF mixture solvent at 25°C. Chemical compositions, molecular weight, and structure of the obtained PFCPSQs were characterized using 1H NMR, 29Si NMR, FT-IR, and GPC. Dielectric values were examined by a HP-4190 system and a dielectric constant k of 1.92 was obtained. [ABSTRACT FROM AUTHOR]

Polymethylsilsesquioxane(PMSQ)s with photo-curable groups were prepared by copolymerization of alkoxysilanes. Poly(acryloyl-co-methylsilsesquioxane)(PAMSQ)s of various mole ratio acryloyl group (6 mol%, 12 mol%, 24 mol%, 48 mol%, 100 mol%) were obtained from copolymerization of methyltrimethoxylsilane and 3-(trimethoxysilyl)propyl acrylate. Optical and photonic curable properties were studied by near infrared region spectra, prism coupler, UV-visible spectra, and photo-DSC. The optical losses were below 0.002 dB/cm at 830, 1330, and 1550 nm, respectively. Optical loss was found to be independent of a molar ratio of functional group. [ABSTRACT FROM AUTHOR]

UV crosslinkable sulfonated block copolymers of neopentyl p-styrene sulfonate (NSS) and 2-cinnamoylethyl acrylate (CEA) were synthesized by living radical polymerization. For this, the block copolymers of 2-(trimethylsilyl)ethyl acrylate (TMSEA) and NSS were first synthesized by sequential CuBr catalyzed living radical polymerization with 2-bromopropionate (EBP) initiator and N,N,N',N'-pentamethylethyleneamine (PMDETA) ligand. Obtained well defined block copolymers (polydispersity <1.21) were then hydrolyzed with an acid to give the block copolymer of 2-hydroxylethyl acrylate (HEA) and NSS. Cinnamoyl chloride as a crosslinking moiety reacted with the hydrolyzed block copolymers to give final UV crosslinkable sulfonated block copolymers. Theses block copolymers were successfully crosslinked under UV irradiation and generated sulfonic acid groups by thermolysis of the PNSS. [ABSTRACT FROM AUTHOR]

Physical and optical properties of a series of TAC films with different molecular weight synthesized by acetylation of cotton linter have been investigated. The synthesized TACs had fully acetylated structure in which acetic acid contents was about 62%. Dimensional stability, thermal stability, modulus, tensile strength and elongation at break of TAC film were influenced by the molecular weight of base resin and they increased with the molecular weight. TAC films had good transparency as well as optical isotropy. Especially, optical property and moderate physical properties for protective film application in LCD were achieved above the molecular weight of 250 kg/mol. [ABSTRACT FROM AUTHOR]

Ladder-like structured polysilsesquioxane with carbazole groups showed unexpected high photo- and electroluminescence efficiencies both in solution and solid states due to its rigid silicone ladder structures, which efficiently isolated the carbazole groups and thus suppressed their excimer formations by inter- and intramolecules. [ABSTRACT FROM AUTHOR]