Yunhee Kim

The burden of nosocomial staphylococcus aureus bloodstream infection in South Korea: a prospective hospital-based nationwide study

BackgroundWe estimated the nationwide burden of nosocomial S. aureus bloodstream infection (SA-BSI), a major cause of nosocomial infection, in South Korea.MethodsTo evaluate the nationwide incidence of nosocomial SA-BSI, cases of SA-BSI were prospectively collected from 22 hospitals with over 500 beds over 4?months. Data on patient-days were obtained from a national health insurance database containing the claims data for all healthcare facilities in South Korea. The additional cost of SA-BSI was estimated through a matched case?control study. The economic burden was calculated from the sum of the medical costs, the costs of caregiving and loss of productivity.ResultsThree hundred and thirty nine cases of nosocomial SA-BSI were included in the study: 254 cases of methicillin-resistant SA-BSI (MRSA-BSI) and 85 cases of methicillin-susceptible SA-BSI (MSSA-BSI). Death related to BSI occurred in 81 cases (31.9%) of MRSA-BSI and 12 cases (14.1%) of MSSA-BSI. The estimated incidence of nosocomial MRSA-BSI was 0.12/1,000 patient-days and that of nosocomial MSSA-BSI, 0.04/1,000 patient-days. The estimated annual cases of nosocomial BSI were 2,946 for MRSA and 986 for MSSA in South Korea. The additional economic burden per case of nosocomial SA-BSI was US

Measurement of the optical characteristics of electrowetting prism array for three-dimensional display

20,494 for MRSA-BSI and

Arrayed beam steering device for advanced 3D displays

6,914 for MSSA-BSI. Total additional annual cost of nosocomial SA-BSI was

Interfacial waves generated by electrowetting-driven contact line motion

67,192,559.ConclusionIn view of the burden of nosocomial SA-BSI, a national strategy for reducing nosocomial SA-BSI is urgently needed in South Korea.

Development of micro variable optics array

Recently liquid-based optical devices are emerging as attractive components in three-dimensional (3D) display for its compact structure and fast response time. Among them an electrowetting prism array is one of the promising 3D devices. It steers a beam, which enables to provide corresponding perspectives to observer. For high quality autostereoscopic 3D displays the important factors are the beam steering angle and the beam profile, the optical characteristics. In this paper, we propose a method to measure the optical characteristics of the liquid prism and show experimental results on our prototype electrowetting prism array, which consists of prisms with 200um by 200um size. A modified 4-f system is adopted for the proposed method. It provides two kinds of information of the optical characteristics of the liquid prism at the image plane and at the Fourier plane. First, the proposed measurement setup magnifies the image of the liquid micro prism array so that we can observe the status of the each prism array directly with bare eye and align a mask easily for selecting a prism to be examined at the image plane. Secondly, the steering angle can be calculated by measuring the displacement of the beam at the Fourier plane, where the angular profiles that have important information on the oilwater interface is observed precisely. The principle of the proposed method will be explained, and the measured optical characteristics from experimental results on the liquid prism we fabricated will be provided, which proves the validity of the measurement method.

Coherent backlight unit using holographic optical elements for full-color flat-panel holographic display

An arrayed beam steering device enables much simplified system architectures for high quality multiview 3D displays by adapting time multiplexing and eye tracking scheme. An array device consisting of microscale liquid prisms is presented, where the prism surface between two immiscible liquids is electrically controlled to steer light beams by the principle of electrowetting. An array prototype with 280×280μm pixels was fabricated and demonstrated of its full optical performances. The maximum tilting angle of each prism was measured to be 22.5° in average, with a tracking resolution of less than 0.04°. In this paper, we report a design and fabrication of eletrowetting based prism array, opto-fluidic simulations, optical characterizations, as well as applications to achieve low fatigue 3D displays.

Investigation of Hot carrier Degradation in Grooved Channel Structure nMOSFETs: Sphere shaped Recess Cell Array Transistor (SRCAT)

The contact angle of a liquid-fluid interface can be effectively modulated by the electrowetting-on-dielectric (EWOD) technology. Rapid movement of the contact line can be achieved by swift changes of voltage at the electrodes, which can give rise to interfacial waves under the strong influence of surface tension. Here we experimentally demonstrate EWOD-driven interfacial waves of overlapping liquids and compare their wavelength and decay length with the theoretical results obtained by a perturbation analysis. Our theory also allows us to predict the temporal evolution of the interfacial profiles in either rectangular or cylindrical containers, as driven by slipping contact lines. This work builds a theoretical framework to understand and predict the dynamics of capillary waves of a liquid-liquid interface driven by EWOD, which has practical implications on optofluidic devices used to guide light.

DISPLAY INCLUDING ELECTROWETTING PRISM ARRAY

This research is on the development of a micro variable optics array which employs electrowetting as the working principle. The single pixel of the array has four separated electrodes and each of them is controlled independently giving the device multi-degree of freedom. The separated electrodes are fabricated using a thick photoresist and electroplating. Several formulas showing the relation among the radius of curvature, the prism angle, and electrowetting parameters are provided. The prism angles are measured to be ±30° and compared to the calculated values. The measurement of the radius of curvature is also presented showing that the various radiuses of curvature are achievable from concave to convex.

Electron-beam-induced transition aluminas from aluminum trihydroxide

We propose the coherent backlight unit (BLU) using Holographic Optical Element (HOE) for full-color flat-panel holographic display. The HOE BLU consists of two reflective type HOEs that change the optical beam path and shape by diffraction. The diverging incident beam is transformed to the collimated beam which has a very small diffraction angle (7.5°) by HOE 1 (H1) in order to illuminate the whole display. This collimated beam is converged to a point at a distance from the glass substrate by HOE 2 (H2). As a result, the diverging incident beam is converted to a point light by H1 and H2. When the high resolution Spatial Light Modulator (SLM) displaying Computer Generated Hologram (CGH) is illuminated by HOE BLU, the hologram image is displayed at a view point near focal point. Practically, we fabricated the full color HOE BLU for 5.5 flat panel holographic display by using the proposed design. At least 5.5 size of HOE is required to illuminate the whole panel. For this reason, we recorded 150 mm x 90 mm size HOE on the 10 mm thickness glass substrate. This HOE BLU exhibits a total efficiency of 8.0% at Red (660 nm), 7.7% at Green (532 nm), 3.2% at Blue (460 nm) using optimized recording conditions for each wavelength. Finally, a bright full color hologram image was achieved.

3D IMAGE DISPLAY APPARATUS INCLUDING ELECTROWETTING LENS ARRAY AND 3D IMAGE PICKUP APPARATUS INCLUDING ELECTROWETTING LENS ARRAY

In this paper, first, it has been discussed hot carrier reliability in both Pch, RCAT and SRCAT. Second, we showed the origin of electric field suppression where the supply-voltage is applied at the same bias condition. Furthermore, we discuss the effects of ion implant process