9,651 research outputs found

    Development of accuracy enhancement system for boron meters using multisensitive detector for reactor safety

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    Boric acid is used as a coolant for pressurized-water reactors, and the degree of burnup is controlled by the concentration of boric acid. Therefore, accurate measurement of the concentration of boric acid is an important factor in reactor safety. An improved system was proposed for the accurate determination of boron concentration. A new boron-concentration measurement technique, called multisensitive detection, was developed to improve the measurement accuracy of boron meters. In previous studies, laboratory-scale experiments were performed based on different sensitivity detectors, confirming a 65% better accuracy than conventional single-detector boron meters. Based on these experimental results, an experimental system simulating the coolant-circulation environment in the reactor was constructed; accuracy analysis of the boron meter with a multisensitivity detector was performed at the actual coolant pressure and temperature. In this study, the boron concentration conversion equation was derived from the calibration test, and the accuracy of the boron concentration conversion equation was examined through a repeatability test. Through the experiment, it was confirmed that the accuracy was up to 87.5% higher than the conventional single-detector boron meter

    Two-dimensional heterogeneous photonic bandedge laser

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    We proposed and realized a two-dimensional (2D) photonic bandedge laser surrounded by the photonic bandgap. The heterogeneous photonic crystal structure consists of two triangular lattices of the same lattice constant with different air hole radii. The photonic crystal laser was realized by room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells emitting at 1.55 micrometer. The lasing mode was identified from its spectral positions and polarization directions. A low threshold incident pump power of 0.24mW was achieved. The measured characteristics of the photonic crystal lasers closely agree with the results of real space and Fourier space calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure

    Emerging roles of desumoylating enzymes

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    AbstractPosttranslational modification by small ubiquitin-like modifier (SUMO) controls diverse cellular processes including transcriptional regulation, nuclear transport, cell-cycle progression, DNA repair, and signal transduction pathway. Sumoylation is a highly dynamic process that is reversed by a family of Sentrin/SUMO-specific proteases (SENPs). Thus, desumoylation process must be important for regulation of the fate and function of SUMO-conjugated proteins as well as SUMOylation process. SENPs catalyze the removal of SUMO from SUMO-conjugated target proteins as well as the cleavage of SUMO from its precursor proteins. Since the first report of yeast desumoylating enzymes, many studies have revealed the structural and cellular biological properties of SENP family. This review focuses on the specificity of the SENPs' catalytic activities with regard to SUMO isoforms and their emerging roles as cellular regulators

    5-dim Superconformal Index with Enhanced En Global Symmetry

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    The five-dimensional N = 1 supersymmetric gauge theory with Sp(N) gauge group and SO(2N(f)) flavor symmetry describes the physics on N D4-branes with N-f D8-branes on top of a single O8 orientifold plane in Type I&apos; theory. This theory is known to be superconformal at the strong coupling limit with the enhanced global symmetry ENf+1 for N-f <= 7. In this work we calculate the superconformal index on S-1 x S-4 for the Sp(1) gauge theory by the localization method and confirm such enhancement of the global symmetry at the superconformal limit for N-f <= 5 to a few leading orders in the chemical potential. Both perturbative and (anti) instanton contributions are present in this calculation. For N-f = 6, 7 cases some issues related the pole structure of the instanton calculation could not be resolved and here we could provide only some suggestive answer for the leading contributions to the index. For the Sp(N) case, similar issues related to the pole structure appear.1151sciescopu

    Efekat uključivanja u hranljive smeše aditiva različitog porekla na rast, telesni sastav i otpornost mlađi crnog morskog grgeča (sebastes schlegeli)

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    U radu je tvrđen efekat uključivanja u hranljive smeše aditiva različitog porekla [đumbir (CG), fermentisana sojina pasta (CJ), borovnica (BB), japanska jabuka (PM), paradajz (TT), brokoli (BC) i jakon (YC)] na rast, telesni sastav i otpornost mlađi crnog morskog grgeča. Hiljadu šesto osamdeset riba je nasumično raspoređeno u 24 protočna tanka zapremine 200 L. Pripremljeno je osam oglednih smeša za ishranu: kontrolna bez dodataka (Con) i smeše sa dodatkom GG, CJ, BB, PM, TT, BC i YC. Svaka od smeša korišćena je u tri tanka, a ribe su 7 nedelja ručno hranjene do sitosti. Posle isteka ovog perioda, dvadeset riba iz svakog tanka inficirano je sa Streptococcus parauberis i praćeno narednih 10 dana. Prirast i specifična stopa rasta (SGR) bili su veći kod riba koje su u hrani dobijale jakon (YC) nego kod onih koje su hranjene drugim smešama. Kumulativni mortalitet do 5. dana posle infekcije bio je niži kod riba koje su hranjene smešama sa dodatkom GG, BB i YC nego kod ostalih jedinki. U zaključku, smeša sa dodatkom YC pokazala se kao najbolja u smislu poboljšanja prirasta i SGR kod crnog morskog grgeča. Osim toga, dodatak GG, BB i YC u smeše bio je najefikasniji u smanjivanju mortaliteta crnog morskog grgeča usled infekcije sa S. parauberi
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