Sewon Oh

Optimization of the Dual-layer LGP for Improving Luminance and Uniformity of Edge Type Back Light Unit

A dual-layer light guide plate (DLGP) was designed and a simulation was done to optimize the structure of the light guide plates used at backlight units while maintaining the luminance, uniformity and viewing angle by reducing the optical sheet. The characteristic of DLGP with prism pattern with curvature on the top surface is simulated and the luminance and uniformity are obtained. In order to improve the uniformity, the V groove prism pattern on the bottom surface was turned by an angle of . In particular, we used the pitch calculation program to select the value of the ratio (Max : Min) between the pitch at the extreme outside and the pitch at the middle, the number of V groove lines and the variance at the bottom pattern of DLGP. After that, the optimum distance between V grooves was determined. For optimizing the DLGP, we examined the uniformity again by changing the number of pattern grooves on the bottom surface of DLGP. As a result of the simulation, we find that the BLU with DLGP has a uniformity of 90.6% and viewing angle .

Proline accumulation in response to high temperature in winter-acclimated shoots of Prunus persica: a response associated with growth resumption or heat stress?

Abstract: Our previous study revealed that proline (Pro) accumulated in peach trees when cold-acclimated shoots were exposed to higher temperatures. In this study, we determined whether such Pro accumulation is indeed a high temperature-stress response or metabolic preparation for growth resumption. Two studies were conducted to address this question using ‘Daewol’ peach trees. In study 1 (February), Pro content of eco-dormant shoots increased when cold-acclimated plants were exposed to two heat treatments (HTs) but remained unchanged during the intervening cold treatment (CT). Concurrently, ornithine-delta-aminotransferase (OAT) and Δ1-pyrroline-5-carboxylate reductase (P5CR) genes were up- and down-regulated after two HTs and the CT, respectively. Study 2, conducted with growing trees (May), showed that Pro did not change and expression of P5CR and OAT was down-regulated when trees were subjected to either HT or CT; HT and CT used here constituted ‘stress’ treatments as revealed by the decline in chlorophyll fluorescence. Taken together, these results suggest that Pro accumulation (study 1) may be associated with the preparation for growth resumption and not ‘stress’. Furthermore, results from parallel gene expression studies suggest that the ornithine, rather than glutamate, pathway may be the primary Pro biosynthesis route both during growth resumption and high temperature stress in ‘Daewol’ peach.

Proline accumulation and related gene expression during spring regrowth in three rosaceae species

Proline (Pro), one of amino acids, not only acts as an osmoprotectant but also is involved in plant developmental processes. We previously revealed that Pro levels increased in peach (Prunus persica) shoots during dehardening in response to warmer temperatures during spring or in controlled laboratory conditions. Our subsequent work suggested that such Pro accumulation is associated with the resumption of growth in eco-dormant shoots and mediated via the ornithine pathway in peach. The present study was conducted to explore whether the aforementioned Pro accumulation response also occurs in other species of the Rosaceae family. Our data indicate that the Pro content of peach and plum (P. salicina) shoots increased during the spring regrowth and were highly similar between these two related species. Whereas the ornithine-δ-aminotransferase (OAT) gene expression dynamics in peach were correlated with Pro accumulation pattern and with pyrroline-5-carboxylate reductase (P5CR) gene expression, OAT expression was not correlated with the Pro content in plum. For apple (Malus domestica), while the absolute amounts of Pro content differed from those of the two Prunus species, this species accumulated Pro during the spring warming/regrowth. These results suggest that Pro accumulation in response to higher temperatures during the spring regrowth is a more general phenomenon across Rosaceae fruit trees, and although peach shoots may accumulate Pro via the ornithine pathway during spring regrowth, there was no evidence for this in plum and apple.