This study examined how green technology (GT) has evolved recently in the domain of national research and development (R&D) in Korea. The analysis considered social network analysis by using keywords of national R&D projects in environmentally benign ('green' in this paper) technologies. Data for analysis were collected from the R&D database of the National Science and Technology Information Service (NTIS). By selecting the official GT category in the NTIS's database, we gathered 53,896 GT R&D projects from 2011 to 2016 inclusive. By constructing a co-occurrence matrix with keywords, we conducted a centrality analysis (including degree, closeness, betweenness centrality) and visualized the network matrix to display a cluster map. This study presents the following findings: (1) the chronical trends of GT R&D, (2) focused fields of GT R&D, (3) the relations between keywords and GTs, and (4) the characteristics and problems in GT R&D. The paper ends with suggested policy implications to boost national GT R&D and to develop GTs in the future.
To improve the thermal conductivity and wear resistance of ceramic materials in the field of renewable energy technologies, diamond coating by plasma processing has been carried out in recent years. This study's goal is to improve diamond deposition on Al2O3 ceramic substrates by plasma surface treatments. Before diamond deposition was carried out in a vacuum, plasma surface treatments using Ar gas were conducted to improve conditions for deposition. We also conducted plasma processing for diamond deposition on Al2O3 ceramic substrates using a DC arc Plasmatron. The Al2O3 ceramic substrates with diamond film (5 x 15 mm2), were investigated by SEM (Scanning Electron Microscopy), AFM (Atomic Force Microscopy) and XRD (X-ray Diffractometer). Then, the C-H stretching of synthetic diamond films by FTIR (Fourier Transform Infrared Spectroscopy) was studied. We identified nanocrystalline diamond films on the Al2O3 ceramic substrates. The results showed us that the deposition rate of diamond films was 2.3 microm/h after plasma surface treatments. Comparing the above result with untreated ceramic substrates, the deposition rate improved with the surface roughness of the deposited diamond films.
The concept of a water surface plasma source (WSPS) was proposed to directly interact plasmas with water for large area water treatment, which is the type of volume dielectric barrier discharge (vDBD) with plate-to-plate. One electrode is submerged in water, while the other is floated in air, which is covered with a dielectric material. The characteristics of the WSPS were investigated by using a complementary metal-oxidesemiconductor (CMOS) camera, voltage and current probes, and optical emission spectroscopy (OES). The electrochemical parameters of plasma-activated water (PAW, 2 L) after plasma treatment times of 3 min by the WSPS were analyzed by using a multiparameter meter. As results, the formation of the water wave due to plasma generation, caused by the effect of the induced polarization forces, was observed at the WSPS. By comparison with the tap water, the applied voltage of the distilled water required higher than 130% for stable operation of the WSPS due to lower electrical conductivity (EC). As gap distance between dielectric plate and water surface increased, the applied voltage increased. In addition, an increase of 2 mm in the water level from the lower electrode required an approximately 5% increase in applied voltages for the ignition and stable plasma generation of the WSPS. The dominant peaks that were for N 2 species system in the spectrum of plasmas at the WSPS were analyzed by using the OES. In the case of distilled water, the pH values decreased from 6.25 to 4.24 and the EC increased from 2.00 to 22.33 µS • cm by using multiparameter meter during plasma treatment, whereas in the case of tap water, the effects on the pH and EC were insignificant.
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