DETERMINATION OF THE 129I IN PRIMARY COOLANT OF PWR

Among the radioactive wastes generated from the nuclear power plant, a radioactive nuclide such as 129I is classified as a difficult-to-measure (DTM) nuclide, owing to its low specific activity. Therefore, the establishment of an analytical procedure, including a chemical separation for 129I as a representative DTM, becomes essential.In this report, the adsorption and recovery rate were measured by adding 125I as a radio-isotopic tracer (t1/2 = 60.14 d) to the simulation sample, in order to measure the activity concentration of 129I in a pressurized-water reactor primary coolant. The optimum condition for the maximum recovery yield of iodine on the anion exchange resins (AG1 x2, 50-100 mesh, Cl− form) was found to be at pH 7.In this report, the effect of the boron content in a pressurized-water reactor primary coolant on the separation process of 129I was examined, as was the effect of 3H on the measurement of the activity of iodine. As a result, no influence of the boron content and of the simultaneous 3H presence was found with activity concentrations of 3H lower than 50 Bq/mL, and with a boron concentration of less than 2,000 μg/mL

A Study on Urban Regeneration Policy Change in Korea

After the physical redevelopment and reconstruction in the late 1970s, the paradigm on urban regeneration in Korea shifted from maintenance to restoration and sustainability. This study highlighted that those changes occurred rapidly and not gradually over a short period of time. This study researched diachronic changes on urban regeneration policies after the 1970s in Korea using an analysing model that compensated for the theoretical limits of Hogwood and Peters. The limitations of former policies and internal and external socio-economic factors are shown to have affected dynamic policy changes. This study’s academic significance is that it suggests policy implications for cities that have similar urban growth processes to Korea

Central vs. Peripheral Vision during a Singe-Leg Drop Jump: Implications of Dynamics and Patellofemoral Joint Stress

Landing on a single-leg without receiving direct visual information (e.g., not looking at the ground) may increase the risk of injury. We examined whether visual focus contributed to the changing lower-extremity dynamics and patellofemoral joint stress during a single-leg drop jump task. Twenty healthy volunteers visited the laboratory for three separate sessions. During each session, participants randomly performed either of two types of a single-leg drop jump task from a 30 cm high wooden box. Subsequently, participants looked at the landing spot (central vision condition) or kept their heads up (peripheral vision condition) when performing the task. Sagittal and frontal plane lower-extremity joint angles and joint moments (in the ankle, knee, and hip), including the vertical ground reaction force, and patellofemoral joint stress during the first landing phase (from initial contact to peak knee flexion) were compared. Greater ankle inversion and hip adduction were observed when landing with the peripheral vision condition. However, the magnitudes were negligeable (Cohen’s d effect siz

Angle-tolerant linear variable color filter based on a tapered etalon

We propose and fabricate a linear variable color filter (LVCF) that possesses an enhanced angular tolerance in conjunction with a wide linear filtering range (LFR) by taking advantage of an Ag-TiO2-Ag configuration. The TiO2 cavity is tapered in thickness along the device so that the resonance wavelength can be continuously tuned according to the position. In addition, the metal-dielectric-metal structure is overlaid with a pre-designed graded anti-reflection coating in SiO2 to complete the etalon, thereby maximizing the transmission efficiency across the entire device. The tapered dielectric layers in the proposed filter were fabricated via glancing angle deposition without the help of any mask or moving parts. The center wavelength was scanned from 410 nm to 566 nm, resulting in an LFR of 156 nm, and the overall spectra exhibited an approximate peak transmission of 40% and spectral bandwidth of 68 nm. The angular tolerance was as large as 45°, incurring a fractional wavelength shift below 4.2%. The resonance wavelength was verified to be linearly dependent on the position, providing a linearity beyond 99%. The proposed LVCF will thus be actively utilized in a portable micro-spectrometer and spectral scanning device.National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No. 2016R1A2B2010170); ARC Future Fellowship FT110100853