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A new burnup calculation method for burnable absorber-containing fuels called the Advanced Optimally-Weighted Predictor-Corrector (AOWPC) method is proposed based on the OWPC method. The AOWPC meth...

The impact of various parameters in the coarse mesh finite difference (CMFD) acceleration method on overall convergence behavior is investigated through numerical calculations using the method of c...

This paper proposes a new high step-up interleaved dc-dc converter for embedded applications with power electronics circuits. The proposed circuit consists of two boost converters and a switched-capacitor (SC) converter. To reduce the ripple current in the boost inductors, these boost converters are controlled to be in an interleaved operation. Additionally, the output terminals of the boost converters are connected in series hence the double output voltage. On the other hand, the SC converter also boosts-up the output voltage of the boost converters to obtain a higher boost ratio. The operation of the boost converters and the SC converters are cooperatively controlled through a coupled inductor. This combination of the interleaved boost converters and the switched capacitor converter allows us to achieve both a low current ripple and high step-up ratio operation. This paper explains the operational principle of the proposed circuit and its steady-state analysis. Experimental results confirm that the proposed circuit makes it possible to achieve a high boost-up ratio of 14.2 with 93.6 % power conversion efficiency.

Few-group cross sections of fuel and reflector region are generally used for the core design of LWR. The power distribution and reactivity depend on the few-group cross sections in the core design. The few-group cross sections depend on the fuel adjacent to the reflector region. Therefore, it is necessary to calculate the few-group cross sections. However, the effect of changing fuels adjacent to the radial reflector has not been clarified. Therefore, the purpose of this study is the evaluation of the effect of changing fuels adjacent to the radial reflector on the power distribution and the reactivity in order to clarify the effect of changing fuels adjacent to the radial reflector on the radial reflector cross sections. First, the effect of changing fuels adjacent to the radial reflector on the power distribution is evaluated and is compared to the effect of changing temperature or boron concentration which are generally taken into account in the conventional model of the radial reflector cross sections. In this evaluation, the effect of changing fuels adjacent to the reflector on the radial reflector constant is evaluated by using UO2 and MOX fuels. Furthermore, the effect on the radial reflector constant is evaluated based on the perturbation theory. The results show the effect on power distribution is about 0.3 % at maximum, and the effect on the reactivity is quite low (< 1 × 10−7Δk/k).

Uncertainties of various neutronics characteristics in commercial boiling water reactor (BWR) and pressurized water reactor (PWR) cores due to cross-section covariance are evaluated by the Latin Hypercube Sampling (LHS) method, which is an efficient random sampling algorithm. Thermal-hydraulic feedback and burnup effects are fully and explicitly taken into account using a licensing-grade core simulator. Uncertainties for various core characteristics are evaluated by the statistical processing of core calculation results based on the LHS method. The calculation results indicate that uncertainty of critical eigenvalue (i.e., core reactivity) in the BWR core is comparable to that of a typical PWR core. On the other hand, uncertainties of assembly relative power distribution and maximum assembly burnup in the present BWR core are much smaller than those of the present PWR core. The strong thermal-hydraulic feedback effect in the BWR core significantly contributes to the difference of uncertainties in ...

A cross section adjustment method based on the random sampling technique is proposed. In the proposed method, correlations among cross sections and core parameters are used instead of sensitivity c...

The thionation and cyclization of N-(ω-halogenoalkyl)-substituted amides (and related compounds) with Lawesson's reagent (LR=2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide) has been investigated. Treatment of the amides 1 with LR gave the corresponding thioamides 2 in moderate to good yields (Table). The latter, upon treatment with base, afforded, either in a separate step or in a one-pot procedure, the cyclized title compounds, i.e., the 4,5-dihydro-1,3-thiazoles 3 or the corresponding 5-6-dihydro-4H-thiazines 4via dehydrohalogenation.

Viscosity of magnetic fluid changes when an interaction angle between magnetic field and flow vorticity changes. The test shows that viscosity becomes maximum when they cross perpendicularly and becomes minimum when they are parallel. These phenomena were studied theoretically by M. I. Shliomis and W. F. Hall. This paper describes an analysis of the relation between viscosity and the interaction angle from test results and the comparison between that and the theory.

The spin-lattice relaxation rate 1/ T 1 and the Knight shift were measured for La 1.85 Sr 0.15 CuO 4 and YBa 2 Cu 4 O 8 under pressure to 1.4 GPa. The results together with the previously reported pressure dependence of the nuclear quadrupole frequency, ν Q , give evidence that the local hole distribution changes under pressure. In La 1.85 Sr 0.15 CuO 4 , the hole density in the Cu 3d orbit decreases, accompanying a suppression of the antiferromagnetic spin fluctuation of the low-energy component. In YBa 2 Cu 4 O 8 , by contrast, the spin fluctuation changes little while the total hole number in the CuO 2 plane increases. We argue that such changes in the hole distribution are responsible for the T c increase in the respective compounds. We also found that the so-called “spin-gap” behavior in YBa 2 Cu 4 O 8 becomes more pronounced under pressure.

To evaluate the effects of antianginal agents on the correlation between rate-pressure product and myocardial oxygen uptake, multistage supine leg exercise tests were performed by 21 patients with stable effort-induced angina pectoris before and after administration of antianginal drugs (a calcium channel blocker of the dihydropyridine class [10 mg of nisoldipine orally] in 11 patients and a beta-blocker [0.2 mg/kg of propranolol intravenously] in 10 patients). The rate-pressure product was closely correlated with myocardial oxygen uptake before and after administration of each drug. However, the slope of the regression line of rate-pressure product (X) and myocardial oxygen uptake (Y) became significantly steeper after the calcium channel blocker administration, and the Y-intercept was significantly increased by administration of the beta-blocker. Myocardial oxygen uptake was increased after administration of the calcium channel blocker and the beta-blocker compared with control values at corresponding rate-pressure product. These observations should be considered when the rate-pressure product is used to predict myocardial oxygen uptake in patients with angina pectoris who are receiving antianginal drugs.

To determine whether the postexercise systolic blood pressure (SBP) response is a useful marker of left ventricular filling abnormalities, supine leg exercise testing was conducted in 14 control subjects and 70 patients with coronary artery disease (CAD). An abnormal postexercise SBP response (the ratio of SBP after 3 min of recovery to the peak exercise SBP) was defined as 0.85 or more, which represented the cutoff point with the highest sensitivity and specificity for prediction of pulmonary artery wedge pressure (PAWP) of at least 20 mmHg at peak exercise in CAD patients. There was a significant difference between the SBP ratios of the two groups (Control, 0.72±0.05; CAD, 0.86±0.13; p

To evaluate the clinical significance of simple heart rate-adjusted ST segment depression (delta ST/delta HR) in the diagnosis of coronary artery disease, 42 patients with stable exertional angina underwent supine leg exercise testing and cardiac catheterization. During exercise, heart rate, a multilead electrocardiogram, and pulmonary artery wedge pressure were recorded. The sensitivity and accuracy of the delta ST/delta HR criteria (greater than or equal to 3.0 microV/beat/min) were significantly greater than the conventional analysis of ST segment depression criteria (greater than or equal to 0.2 mV) for detecting three-vessel coronary artery disease at a matched specificity of 72% (100% versus 46%, 81% versus 64%, p less than 0.01). A significant linear correlation was found between maximum pulmonary artery wedge pressure increments during exercise (delta PAWP) or Gensini score and the delta ST/delta HR (delta PAWP: r = 0.51, p less than 0.001; Gensini score: r = 0.47, p less than 0.001). There were no statistically significant differences in the delta PAWP or Gensini score between patients with three-vessel disease who had delta ST/delta HR greater than or equal to 3.0 microV/beat/min and those with one- or two-vessel disease who had delta ST/delta HR greater than or equal to 3.0 microV/beat/min (delta PAWP: 18.1 +/- 2.0 versus 21.9 +/- 3.3, p = NS; Gensini score: 68.5 +/- 6.6 versus 66.3 +/- 11.3, p = NS). These findings demonstrate that delta ST/delta HR is more useful than a conventional analysis of ST segment depression for identifying not only anatomically severe coronary artery disease but also functionally severe coronary artery disease.

This paper proposes to apply machine learning techniques to the task of combining outputs of multiple LVCSR models. The proposed technique has advantages over that by voting schemes such as ROVER, especially when the majority of participating models are not reliable. In this machine learning framework, as features of machine learning, information such as the model IDs which output the hypothesized word are useful for improving the word recognition rate. Experimental results show that the combination results achieve a relative word error reduction of up to 39% against the best performing single model and that of up to 23% against ROVER. We further empirically show that it performs better when LVCSR models to be combined are chosen so as to cover as many correctly recognized words as possible, rather than choosing models in descending order of their word correct rates.

Polylactic acid (PLA) is a biomass material made of starch. Compact disc recordable (CD-R) discs with a PLA substrate were prepared and their properties were measured. Although the glass transition point of PLA is lower than that of polycarbonate (PC), the PLA substrate is usable for CD-R discs. It was confirmed that the substrate is usable for recordable optical discs at temperatures under 50 °C.

New chiral ligands, bis-thiazoline derivatives (sulfur analogues of known oxazolines) were prepared from chiral bis-(N-acylamino alcohols) with Lawesson's reagent. Bis-thiazolines thus obtained proved to be useful chiral ligands for metal in asymmetric Diels–Alder reaction.

A second peak in magnetization curve has been observed in La 2-xSrxCuO4 with x = 0.15 and 0.18, while not observed for x = 0. 115. We have evaluated flux pinning energy U eff from magnetic relaxation near the second peak. It was found that U eff showed a maximum at the field less than the field where the second peak observed. The field H efi, where U eff shows a maximum, has been expressed by a relation \(\sqrt {{H_{eff}}} = c(x)(1 - T/{T_c}J)\) . The relaxation behavior in this system cannot be explained from the collective pinning theory. Temperature dependence of the second peak has been compared with that in YBCO. The origin of the second peak is suggested to be different from that in YBCO.

FK409 is a novel vasodilator with a unique chemical structure. We wished to elucidate the mechanisms of antianginal action of FK409 in dynamic exercise-induced angina. Twelve patients with stable effort angina pectoris were studied before and after a single 40-mg oral dose of FK409. Chest pain was induced in all of 12 patients during the control multistage bicycle ergometer exercise. After FK409 administration, the same workload did not induce chest pain in 6 patients. The ST segment at peak exercise showed less severe depression from 0.15 +/- 0.02 to 0.05 +/- 0.01 mV (p < 0.001). Left ventricular (LV) filling estimated by the Doppler method was reduced, and pulmonary artery wedge pressure decreased significantly (p < 0.001) throughout exercise testing after FK409. Myocardial oxygen uptake and coronary sinus flow throughout exercise testing decreased significantly (p < 0.05) after FK409 administration. The results of the present study demonstrate that decrease in myocardial oxygen demand may be caused by pre- and afterload reduction and that it could be a major mechanism of the antianginal action of FK409. However, other mechanisms such as redistribution of coronary blood flow to the subendocardium, direct dilatation of the stenotic parts of the epicardial arteries, and an increase in collateral blood flow should be considered additional possible mechanisms of the antianginal action of FK409.

An uncertainty reduction method for core safety parameters, for which measurement values are not obtained, is proposed. We empirically recognize that there exist some correlations among the prediction errors of core safety parameters, e.g., a correlation between the control rod worth and the assembly relative power at corresponding position. Correlations of errors among core safety parameters are theoretically estimated using the covariance of cross sections and sensitivity coefficients of core parameters. The estimated correlations of errors among core safety parameters are verified through the direct Monte Carlo sampling method. Once the correlation of errors among core safety parameters is known, we can estimate the uncertainty of a safety parameter for which measurement value is not obtained.