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http://hdl.handle.net/10203/23466
2018-05-24T05:38:08ZMeasurement of focal length based on laser-beam-spot tracking system using diffractive beam sampler
http://hdl.handle.net/10203/241557
Title: Measurement of focal length based on laser-beam-spot tracking system using diffractive beam sampler
Authors: Cao, Binh Xuan; Phuong Le Hoang; Ahn, Sanghoon; Kim, Jeng-o; Kang, Heeshin; Noh, Jiwhan
Abstract: An approach for measuring the focal length of a lens using a diffractive beam sampler is presented. The high-precision measurement of the focal length is conducted while a specimen is continuously moved along the optical axis. Images of the fractional beam spots on a charge-coupled-device camera are tracked with respect to the position of the specimen to obtain the relation between the beam-spot distance and the lens-specimen distance. Accordingly, this relation can be used to infer the focal length via computation. The method is carried out by simulation, easy, and inexpensive. In addition, it is applicable to find the focal length of a thin lens as well as the effective focal length of a system of lenses because it does not require the movement or replacement of lenses. The results indicate a dramatically high precision.2018-07-01T00:00:00ZDetectivity analysis for organic photodetectors
http://hdl.handle.net/10203/241560
Title: Detectivity analysis for organic photodetectors
Authors: Kim, Il Ku; Jo, Jun Hyung; Lee, Jinwoo (Brian); Choi, Young Jin
Abstract: In this perspective letter, we report that there is a problem with a detectivity estimation method based on dark current measurement for organic photodiodes (OPDs). Based on dark current, calculated detectivity for fabricated OPD was 4.22 x 10(13) cmHz(1/2)/W at 520 nm. However, calculated detectivity for OPD based on measured noise current was 8.4 x 10(10) cmHz(1/2)/W at 520 nm. Therefore, we found that there are huge differences (more about 3 magnitudes of order) of detectivity calculations based on dark current measurement assumption and our noise measurement analysis. From the calculations of detectivities, it is concluded that noise current analysis should be addressed to clarify the organic photodiode characteristics.2018-06-01T00:00:00ZNew Method of Calculating a Multiplication by using the Generalized Bernstein-Vazirani Algorithm
http://hdl.handle.net/10203/242328
Title: New Method of Calculating a Multiplication by using the Generalized Bernstein-Vazirani Algorithm
Authors: Nagata, Koji; Nakamura, Tadao; Geurdes, Han; Batle, Josep; Abdalla, Soliman; Farouk, Ahmed
Abstract: We present a new method of more speedily calculating a multiplication by using the generalized Bernstein-Vazirani algorithm and many parallel quantum systems. Given the set of real values and a function , we shall determine the following values simultaneously. The speed of determining the values is shown to outperform the classical case by a factor of . Next, we consider it as a number in binary representation; M (1) = (g(a (1)),g(a (2)),g(a (3)),aEuro broken vertical bar,g(a (N) )). By using parallel quantum systems, we have numbers in binary representation, simultaneously. The speed of obtaining the numbers is shown to outperform the classical case by a factor of . Finally, we calculate the product; The speed of obtaining the product is shown to outperform the classical case by a factor of N x M.2018-06-01T00:00:00ZSurface-modified polymer nanofiber membrane for high-efficiency microdust capturing
http://hdl.handle.net/10203/241406
Title: Surface-modified polymer nanofiber membrane for high-efficiency microdust capturing
Authors: Kim, Han-Jung; Park, Seon Joo; Park, Chul Soon; Le, Thanh-Hai; Lee, Sang Hun; Ha, Tai Hwan; Kim, Hyoung-il; Kim, Jinyeong; Lee, Chang-Soo; Yoon, Hyeonseok; Kwon, Oh Seok
Abstract: Particulate matter (PM) pollution is serious human health issue. Various filter technologies have been developed to improve the air filtration efficiency. Recently, nanofibrous membrane filters have received much attention due to its outstanding transparency and high efficiency for PM <= 2.5 mu m (PM2.5) capture/removal compared to conventional micro-structured filters. Although these filters provide high-efficiency PM2.5 capture, obtaining strong PM adhesion via surface engineering remains a challenge. In this study, we demonstrate a high efficiency PM2.5 capture air-filter by electrospun polyacrylonitrile nanofibers (EPNFs). The surface of the EPNFs was modified by oxygen plasma treatment for generating functional groups such as -CONH2, -COOH and -COOR. The EPNFs were utilized as air filter in hand-made PM removal system which is consisted of DC power supply, PM source, PM sensor and PM removal test chamber. The test result showed high air flow and effective air filtration (PM2.5 removal efficiency: 94.02%, pressure drop: 18 Pa, Time to reach the PM level recommended by the World Health Organization (T-WHO (PM2.5)): 15 min, quality factor: 0.1564 Pa-1) compared to commercial filters. The intermolecular interaction between the plasma-treated EPNFs (PEPNFs) and PMs was investigated by density functional theory (DFT) calculations. The PEPNF filter showed high long-term reproducibility in a cycle test with a high PM concentration (over 2,000 mu gm(-3)). The filter was applied as a car interior air purifier using a cigar jack as a power supply, ca. 16 min was required to reach the PM level recommended by the World Health Organization (<25 mu gm(-3)).2018-05-01T00:00:00Z