Chung-Ang University

About: Chung-Ang University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Thin film. The organization has 13381 authors who have published 26978 publications receiving 416735 citations. The organization is also known as: CAU & Chung.

Rb 3 VO(O 2 ) 2 CO 3 : A Four-in-One Carbonatoperoxovanadate Exhibiting an Extremely Strong Second-Harmonic Generation Response.

Abstract: A nonlinear optical (NLO) carbonatoperoxovanadate, Rb3 VO(O2 )2 CO3 , was synthesized through a simple solution-evaporation method in phase-pure form. Single-crystal X-ray diffraction revealed that the structure of Rb3 VO(O2 )2 CO3 consists of important noncentrosymmetric (NCS) chromophores, that is, π-delocalized (CO3 )2- groups, a second-order Jahn-Teller (SOJT) distortive V5+ cation, and π-localized distorted O22- groups, as well as charge-balancing polarizable Rb+ ions. The powder second-harmonic generation (SHG) measurements indicated that Rb3 VO(O2 )2 CO3 is phase-matchable (Type I) and exhibits a remarkably strong SHG response circa 21.0 times that of potassium dihydrogen phosphate (KDP), which is the largest efficiency observed among carbonate NLO materials. First-principles calculation analysis suggests that the extremely large SHG response of Rb3 VO(O2 )2 CO3 is attributed to the synergistic effect of the cooperation of all the constituting NCS chromophores.

Flexible active-matrix organic light-emitting diode display enabled by MoS2 thin-film transistor

Abstract: Atomically thin molybdenum disulfide (MoS2) has been extensively investigated in semiconductor electronics but has not been applied in a backplane circuitry of organic light-emitting diode (OLED) display. Its applicability as an active drive element is hampered by the large contact resistance at the metal/MoS2 interface, which hinders the transport of carriers at the dielectric surface, which in turn considerably deteriorates the mobility. Modified switching device architecture is proposed for efficiently exploiting the high-k dielectric Al2O3 layer, which, when integrated in an active matrix, can drive the ultrathin OLED display even in dynamic folding states. The proposed architecture exhibits 28 times increase in mobility compared to a normal back-gated thin-film transistor, and its potential as a wearable display attached to a human wrist is demonstrated.

Environment-Adaptable Artificial Visual Perception Behaviors Using a Light-Adjustable Optoelectronic Neuromorphic Device Array.

Abstract: Emulating the biological visual perception system typically requires a complex architecture including the integration of an artificial retina and optic nerves with various synaptic behaviors. However, self-adaptive synaptic behaviors, which are frequently translated into visual nerves to adjust environmental light intensities, have been one of the serious challenges for the artificial visual perception system. Here, an artificial optoelectronic neuromorphic device array to emulate the light-adaptable synaptic functions (photopic and scotopic adaptation) of the biological visual perception system is presented. By employing an artificial visual perception circuit including a metal chalcogenide photoreceptor transistor and a metal oxide synaptic transistor, the optoelectronic neuromorphic device successfully demonstrates diverse visual synaptic functions such as phototriggered short-term plasticity, long-term potentiation, and neural facilitation. More importantly, the environment-adaptable perception behaviors at various levels of the light illumination are well reproduced by adjusting load transistor in the circuit, exhibiting the acts of variable dynamic ranges of biological system. This development paves a new way to fabricate an environmental-adaptable artificial visual perception system with profound implications for the field of future neuromorphic electronics.

Adventitious root growth and ginsenoside accumulation in Panax ginseng cultures as affected by methyl jasmonate

Abstract: Adventitious roots of ginseng were treated with methyl jasmonate (MJ) up to 150 microM and cultured for 40 days. Up to 100 microM MJ inhibited the root growth but increase ginsenoside accumulation. In a two-stage bioreactor culture, total ginsenosides, after elicitation with 100 microM MJ peaked after 10 days at 48 mg g(-1) dry wt and then dropped sharply. Of the two groups of ginsenosides (Rb and Rg), higher amounts of Rb accumulated in the adventitious roots.