Large area deep ultraviolet light of Al0.47_{0.47}Ga0.53_{0.53}N/Al0.56_{0.56}Ga0.44_{0.44}N multi quantum well with carbon nanotube electron beam pumping

Large area deep ultraviolet (DUV) light is generated by carbon nanotube (CNT) cold cathode electron beam (C-beam) irradiation on Al$_{0.47}$Ga$_{0.53}$N/Al$_{0.56}$Ga$_{0.44}$N multi quantum wells (MQWs) anode. We developed areal electron beam (EB) with CNT cold cathode emitters. The CNT emitters on silicon wafer were deposited with an area of 188 mm$^2$ , and these were vertically aligned and had conical structures. We optimized the C-beam irradiation conditions to effectively excite AlGaN MQWs. When AlGaN MQWs were excited using an anode voltage of 3 kV and an anode current of 0.8 mA, DUV with a wavelength of 278.7 nm was generated in a large area of 303 mm$^2$ . This DUV area is more than 11 times larger than the light emitting area of conventional EB pumped light sources and UV-LEDs

Gain-Scheduled Complementary Filter Design for a MEMS Based Attitude and Heading Reference System

This paper describes a robust and simple algorithm for an attitude and heading reference system (AHRS) based on low-cost MEMS inertial and magnetic sensors. The proposed approach relies on a gain-scheduled complementary filter, augmented by an acceleration-based switching architecture to yield robust performance, even when the vehicle is subject to strong accelerations. Experimental results are provided for a road captive test during which the vehicle dynamics are in high-acceleration mode and the performance of the proposed filter is evaluated against the output from a conventional linear complementary filter

Normal stress difference-driven particle focusing in nanoparticle colloidal dispersion

Colloidal dispersion has elastic properties due to Brownian relaxation process. However, experimental evidence for the elastic properties, characterized with normal stress differences, is elusive in shearing colloidal dispersion, particularly at low Peclet numbers (Pe < 1). Here, we report that single micrometer-sized polystyrene (PS) beads, suspended in silica nanoparticle dispersion (8 nm radius; 22%, v/v), laterally migrate and form a tightly focused stream by the normal stress differences, generated in pressure-driven microtube flow at low Pe. The nanoparticle dispersion was expected to behave as a Newtonian fluid because of its ultrashort relaxation time (2 mu s), but large shear strain experienced by the PS beads causes the notable non-Newtonian behavior. We demonstrate that the unique rheological properties of the nanoparticle dispersion generate the secondary flow in perpendicular to mainstream in a noncircular conduit, and the elastic properties of blood plasma-constituting protein solutions are elucidated by the colloidal dynamics of protein molecules

A New On-The-Move Integer Ambiguity Determination Method for Precise Positioning of Highly Maneuvering Ground Vehicles

In the conventional RTK (Real Time Kinematics), carrier phase measurements should be collected for several minutes in stationary state in order to determine the IA (Integer Ambiguity) in carrier phase to get the precise position. To determine the IA in motion, several OTM-RTK (On-The-Move RTK) methods have been proposed using vehicle dynamics or augmenting additional sensors. This paper presents a new OTM-RTK technique to determine the IA without aids of external sensors for precise positioning of highly maneuvering ground vehicles. In the proposed technique, the initial IA is determined fast by estimating precise position change during epochs using dual frequency carrier phase measurements. Therefore, IA determination of the proposed method is not influence by vehicle dynamics. By field experiment, performance of the proposed technique is analyzed including IA determination time according to vehicle dynamics and the number of visible SV

Characterizing the Efficiency of Perovskite Solar Cells and Light-Emitting Diodes

Metal halide perovskites (MHPs) are being widely studied as a light-absorber for high-efficiency solar cells. With efforts being made throughout the globe, the power conversion efficiency of MHP solar cells has recently soared up to 25.2%. MHPs are now being spotlighted as a next-generation light-emitter as well. Their high color purity and solution-processability are of particular interest for display applications, which in general benefit from wide color gamut and low-cost high-resolution subpixel patterning. For this reason, research activities on perovskite light-emitting diodes (LEDs) are rapidly growing, and their external quantum efficiencies have been dramatically improved to over 20%. As more and more research groups with different backgrounds are working on these perovskite optoelectronic devices, the demand is growing for standard methods for accurate efficiency measurement that can be agreed upon across the disciplines and, at the same time, can be realized easily in the lab environment with due diligence. Herein, optoelectronic characterization methods are revisited from the viewpoint of MHP solar cells and LEDs. General efficiency measurement practices are first reviewed, common sources of errors are introduced, and guidelines for avoiding or minimizing those errors are then suggested to help researchers in fields develop the best measurement practice.

The First Korean Case of KCNQ2 Mutation in a Family with Benign Familial Neonatal Convulsions

Neonatal seizures represent a heterogeneous group of disorders with vastly different etiologies and outcomes. Benign familial neonatal convulsions (BFNC) are a distinctive epileptic syndrome of autosomal dominant inheritance with a favorable prognosis, characterized by the occurrence of unprovoked partial or generalized clonic seizures in the neonatal period or early infancy. Recently, mutations in two potassium channel genes, KCNQ2 and KCNQ3, have been described in this disorder. In this report, we describe a family with BFNC due to a KCNQ2 mutation, the first such family to be described in the Korean population. The diagnosis of BFNC can be made based on clinical suspicion and careful history taking with special emphasis on the familial nature of the disorder. KCNQ2 mutations may be associated with BFNC in a number of different races, as has been reported in other ethnic groups

SYNGAS PRODUCTION WITH A DUAL FLUIDIZED BED GASIFIER FOR POLYGENERATION

A pilot scale dual fluidized bed gasification system was developed for polygeneration with biomass. The gasification system is designed for supplying syngas for Fischer Tropsch (F-T) synthesis of bio-diesel and power generation with a syngas engine. Characteristics of biomass steam gasification were investigated in a lab scale bubbling fluidized bed, and hydrodynamics of a dual fluidized bed were investigated in a cold flow model. Based on the results from the lab scale test and cold flow model, a pilot scale dual fluidized bed gasifier was designed. In this paper, the developing process of the gasifier and preliminary results of system operation will be presented

Flora of Vascular Plants in Ridgelines in the Palgongsa Procincial Park, Korea

AbstractWe investigated and analyzed the flora of vascular plants around ridgelines in the Palgongsan Provincial Park to suggest fundamental data for establishing preservation plans of them. The flora of vascular plants around ridgelines was a total of 587 taxa including 102 familiies, 314 genera, 518 species, 58 varieties, 7 forma, and 4 subspecies. Rare plants designated by Korea Forest Service were 27 taxa including Semiquilegia mandshurica and Aristolochia manshuriensis. Endemic plants were 15 taxa including Clematis trichotoma and Carex okamotoi. Floristic special plants were a total of 100 taxa including all five classes. Naturalized plants were 13 taxa including Phytolacca Americana, ambrosia, and Taraxacum officinale