Subspace identification for continuous-time stochastic systems via distribution-based approach

This paper presents a novel approach for system identification of continuous-time stochastic state space models from random input-output continuous data. The approach is based on the introduction of random distribution theory in describing (higher) time derivatives of stochastic processes, and the input-output algebraic relationship is derived which is treated in the time-domain. The efficacy of the approach is examined by comparing with other approaches employing the filters.     

Development of bellows and gate valves with a comb-type rf shield for high-current accelerators: four-year beam test at KEK B-Factory

Since a comb-type rf shield was proposed in 2003 as a rf shield for future high-intensity accelerators, various types of bellow chambers and gate valves with this rf shield have been installed in the KEK B-Factory rings in series and tested with beams. Through beam tests to check the performance, a structural simplification has been tried in parallel. The temperatures of the bellow corrugations decreased by a factor of 3-6 compared to those with a conventional finger-type rf shield in most cases. The temperatures of the body of the gate valves also decreased by a factor of 2-5. These results demonstrated the availability of the comb-type rf shield. Although a discharge was observed in one simplified model, the latest model has shown no problem up to a stored beam current of 1.8 A (1.3 mA/bunch, 6 mm bunch length). Experiences with the comb-type rf shield in these four-year beam tests are reviewed here.     

SO2-Enhanced Nitration of Fluoranthene and Pyrene Adsorbed on Particulate Matter in the Heterogeneous Reaction in the Presence of NO2

Heterogeneous photoreaction of fluoranthene (FL) or pyrene (PY) adsorbed on solid support under 10 ppm NO₂-air in the presence or absence of SO₂ was investigated in order to clarify the effect of SO₂ on nitroarene formation. Formation yield of nitrofluoranthenes (NFs) and nitropyrenes (NPs) were increased by the addition of SO₂ to reaction atmosphere. 1-, 2-, 7-, and 8-NFs were formed in the presence of SO₂ while 1-, 2-, and 7-NF were detected in the absence of SO₂. After the reaction for 4 h, yield of 2-NF in the presence of 10 ppm of SO₂ was 1.5 times as large as that in the absence of SO₂. 1-NP and 1,3-, 1,6-, 1,8-dinitropyrenes (DNPs) were formed both in the presence and in the absence of SO₂. After the reaction for 2 h, yields of 1-NP and DNPs in the presence of 10 ppm of SO₂ were about three times and twice as large as those in the absence of SO₂, respectively. While the yield of 1-NP and degradation rate of PY were hardly affected by the concentration of SO₂, the yield of DNPs increased with the increase in SO₂ concentration. The isomer distributions of NFs and NPs indicated that NFs and NPs were formed by non-electrophilic nitration and electrophilic nitration, respectively.     

The equilibrium oxygen pressure over the Cr-Y2O3-YCrO3 coexistence measured with the galvanic cell using stabilized ZrO2 solid electrolyte

The equilibrium oxygen pressure over the Cr-Y₂O₃-YCrO₃ coexistence has been measured by the following cells: Cr, Y₂O₃, YCrO₃∥ZrO₂∥Cr, Cr₂O₃ [I] Mn, MnO∥ZrO₂∥Cr, Y₂O₃, YCrO₃ [II] Moreover, the partial electronic conduction parameter,P _e, has been determined simultaneously, as the oxygen partial pressure where then-type electronic and ionic conductivities are equal in the stabilized ZrO₂. The equilibrium oxygen pressure,P _{O 2}, over the Cr-Y₂O₃-YCrO₃ coexistence andP _e are expressed as log (P_{O 2}/atm) = 10.6 − 4.39 × 10⁴1/T ± 0.1 (1385 to 1470 K) log ( P_e/atm = 8.86 − 4.21 x 10₄ 1/T ± 0.3 (1385 to 1470 K) From the equilibrium oxygen pressure and the standard Gibbs energy of formation of Y₂O₃, the standard Gibbs energy of formation of YCrO₃ is calculated as ΔG _o ^f /J mol^™1 = −1.58 x 10⁶ + 2.93 x 10² T ± 7 × 10³ (1385 to 1470 K)     

Preparation of an acrylics‐grafted polyester and its aqueous dispersion—Structural study of acrylics‐grafted polyesters

Structural study of two grafted polyesters, which were different in mechanical properties, was investigated by DMA, TEM, and high‐resolution solid‐state ¹³C‐NMR. Using DMA and TEM, a separated phase larger than 100 nm was not found in the grafted polyesters. The main chain and the side chain seemed miscible. Analysis of T_1ρHs and their distributions made the difference of microstructure in the grafted polyesters clear. P(EA‐AA)‐grafted polyester, which was very brittle, had a separated phase in the grafted polyester. The separated phase was estimated to be at a size of about 3 nm. On the other hand, P(St‐DEF‐MAnh)‐grafted polyester, which was very ductile, had a homogeneous microstructure. The difference in the microstructures of the grafted polyesters seemed to effect the mechanical properties of the grafted polyesters. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 392–402, 2000     

Anodic processes on a titanium-supported Ruthenium dioxide electrode at high potentials in a mixture of sulfuric acid and ammonium sulfate

The anodic polarization behaviours of Ti-supported RuO₂ electrode at high potentials and the electrode reactions, especially oxygen evolution and peroxydisulfate ion formation, were investigated in H₂SO₄(NH₄)₂SO₄ mixed aqueous solutions. The effects of NH₄F addition to the solutions on the anodic processes were also examined.The anodic polarization curve is clearly divided into three parts: in the first linear region only oxygen evolution occurs and in the second one peroxydisulfate ion formation takes place, accompanied by oxygen evolution. The transitional region lies between these two linear regions. However, the oxygen evolution reaction proceeds predominantly in all regions in H₂SO₄(NH₄)₂SO₄ mixed aqueous solutions. The current efficiency for peroxydisulfate ion formation depends on the concentration of (NH₄)₂SO₄ and the current density. The current efficiency is greatly increased by adding NH₄F to the mixed solutions. The formation reaction of peroxydisulfate ion in the NH₄F-containing solutions is controlled by the step of the primary discharge of sulfate ion or hydrogensulfate ion.     

Mechanism underlying specificity of proteins targeting inorganic materials

Adhesion force analysis using atomic force microscopy clearly revealed for the first time the mechanism underlying the specific binding between a titanium surface and ferritin possessing the sequence of Ti-binding peptide in its N-terminal domain. Our results proved that the specific binding is due to double electrostatic bonds between charged residue and surface groups of the substrate. Furthermore, it is also demonstrated that the accretion of surfactant reduces nonspecific interactions, dramatically enhancing the selectivity and specificity of Ti-binding peptide.     

Actinobacillus actinomycetemcomitans toxin induces both cell cycle arrest in the G2/M phase and apoptosis

We found that the culture supernatant of the periodontopathic bacterium Actinobacillus actinomycetemcomitans had a cytotoxic effect on several cell lines. In this study, we purified the toxin from the culture supernatant of A. actinomycetemcomitans Y4 by a four-step procedure: ammonium sulfate precipitation, POROS HQ/M column chromatography, polymyxin B matrix column chromatography, and Mono-Q column chromatography. The purified toxin gave two major bands of protein with molecular masses of 80 and 85 kDa upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The mechanism of cell death of the B-cell hybridoma cell line HS-72 was examined by observing changes in nuclear morphology, an increase in the proportion of fragmented DNA, and the typical ladder pattern of degraded chromosomal DNA, indicating the induction of apoptosis. Overexpression of human Bcl-2 suppressed apoptosis in HS-72 cells, indicating that the toxin from A. actinomycetemcomitans induces apoptosis by a Bcl-2-inhibitable mechanism. Flow cytometric analysis revealed that the toxin caused cell cycle arrest in the G2/M phase and apoptosis in HS-72 cells. In addition, aurintricarboxylic acid, a DNA endonuclease inhibitor, markedly decreased the percentage of apoptotic cells but had no effect on cell cycle arrest in the G2/M phase. Taken together, these findings suggest that the toxin from A. actinomycetemcomitans could mediate the development of periodontal diseases through cell cycle arrest in the G2/M phase and apoptosis in B lymphocytes of periodontal tissue.     

Shock compaction of silicon carbide powder

A series of shock compaction experiments on SiC powder were carried out over a wide range of shock pressures and shock temperatures up to 30 GPa and 3400 K. Large changes in some physical properties and a variety of unique microstructures were observed in the shock-treated samples with changes in impact conditions. For an iron plate impactor, the optimum impact condition, which depends on the initial density, is 2.5 km sec^–1 for 70% initial density and 2.0 km sec^–1 for 50%. The best-sintered compact of SiC with 97% density and micro-Vicker's hardness of 2700 kg mm^–2 was obtained under optimum conditions. Good compacts with high relative density and high strength exhibit the disruptive effects of the shock wave, which are indicated by microstrain increase and crystallite size reduction. The skin model is presented here in order to estimate the heterogeneous shock state which is realized under and after shock loading of the initial powder aggregates.