Pusan National University

About: Pusan National University is a education organization based out in Busan, South Korea. It is known for research contribution in the topics: Catalysis & Population. The organization has 24124 authors who have published 45054 publications receiving 819356 citations. The organization is also known as: Busan National University & Pusan University.

A Wideband CMOS Low Noise Amplifier Employing Noise and IM2 Distortion Cancellation for a Digital TV Tuner

Abstract: A wideband CMOS low noise amplifier (LNA) with single-ended input and output employing noise and IM2 distortion cancellation for a digital terrestrial and cable TV tuner is presented. By adopting a noise canceling structure combining a common source amplifier and a common gate amplifier by current amplification, the LNA obtains a low noise figure and high IIP3. IIP2 as well as IIP3 of the LNA is important in broadband systems, especially digital terrestrial and cable TV applications. Accordingly, in order to overcome the poor IIP2 performance of conventional LNAs with single-ended input and output and avoid the use of external and bulky passive transformers along with high sensitivity, an IM2 distortion cancellation technique exploiting the complementary RF performance of NMOS and PMOS while retaining thermal noise canceling is adopted in the LNA. The proposed LNA is implemented in a 0.18 mum CMOS process and achieves a power gain of 14 dB, an average noise figure of 3 dB, an IIP3 of 3 dBm, an IIP2 of 44 dBm at maximum gain, and S11 of under -9 dB in a frequency range from 50 MHz to 880 MHz. The power consumption is 34.8 mW at 2.2 V and the chip area is 0.16 mm2.

Non-Thermal Atmospheric Pressure Plasma Preferentially Induces Apoptosis in p53-Mutated Cancer Cells by Activating ROS Stress-Response Pathways

Abstract: Non-thermal atmospheric pressure plasma (NTAPP) is an ionized gas at room temperature and has potential as a new apoptosis-promoting cancer therapy that acts by generating reactive oxygen species (ROS). However, it is imperative to determine its selectivity and standardize the components and composition of NTAPP. Here, we designed an NTAPP-generating apparatus combined with a He gas feeding system and demonstrated its high selectivity toward p53-mutated cancer cells. We first determined the proper conditions for NTAPP exposure to selectively induce apoptosis in cancer cells. The apoptotic effect of NTAPP was greater for p53-mutated cancer cells; artificial p53 expression in p53-negative HT29 cells decreased the pro-apoptotic effect of NTAPP. We also examined extra- and intracellular ROS levels in NTAPP-treated cells to deduce the mechanism of NTAPP action. While NTAPP-mediated increases in extracellular nitric oxide (NO) did not affect cell viability, intracellular ROS increased under NTAPP exposure and induced apoptotic cell death. This effect was dose-dependently reduced following treatment with ROS scavengers. NTAPP induced apoptosis even in doxorubicin-resistant cancer cell lines, demonstrating the feasibility of NTAPP as a potent cancer therapy. Collectively, these results strongly support the potential of NTAPP as a selective anticancer treatment, especially for p53-mutated cancer cells.

Block-Copolymer-Assisted One-Pot Synthesis of Ordered Mesoporous WO3−x/Carbon Nanocomposites as High-Rate-Performance Electrodes for Pseudocapacitors

Abstract: An ordered mesoporous tungsten-oxide/carbon (denoted as m-WO3−x-C-s) nanocomposite is synthesized using a simple one-pot method using polystyrene-block-poly(ethylene oxide) (PS-b-PEO) as a structure-directing agent. The hydrophilic PEO block interacts with the carbon and tungsten precursors (resol polymer and WCl6), and the PS block is converted to pores after heating at 700 °C under a nitrogen flow. The m-WO3−x-C-s nanocomposite has a high Brunauer–Emmett–Teller (BET) surface area and hexagonally ordered pores. Because of its mesoporous structure and high intrinsic density of tungsten oxide, this material exhibits a high average volumetric capacitance and gravimetric capacitance as a pseudocapacitor electrode. In comparison with reduced mesoporous tungsten oxide (denoted as m-WO3−x-h), which is synthesized by a tedious hard template approach and further reduction in a H2/N2 atmosphere, m-WO3−x-C-s shows a high capacitance and enhanced rate performance, as confirmed by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The good performance of m-WO3−x-C-s is attributed to the high surface area arising from the mesoporous structure, the large interconnected mesopores, and the low internal resistance from the well-dispersed reduced tungsten oxide and amorphous carbon composite structure. Here, the amorphous carbon acts as an electrical pathway for effective pseudocapacitor behavior of WO3-x.

Next generation ferroelectric materials for semiconductor process integration and their applications

Abstract: Ferroelectrics are a class of materials that possess a variety of interactions between electrical, mechanical, and thermal properties that have enabled a wealth of functionalities. To realize integrated systems, the integration of these functionalities into semiconductor processes is necessary. To this end, the complexity of well-known ferroelectric materials, e.g., the perovskite class, causes severe issues that limit its applications in integrated systems. The discovery of ferroelectricity in hafnium oxide-based materials brought a renewed interest into this field during the last decade. Very recently, ferroelectricity was also verified in aluminum scandium nitride extending the potential of seeing a wealth of ferroelectric functions in integrated electronics in the future. This paper discusses the prospects of both material systems in various applications.