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Absolute cross sections for NO chemisorption, NO decomposition, and cluster dissociation in the collision of a nitrogen monoxide molecule, NO, with cluster ions Con+ and ConH+ (n=2-5) were measured as a function of the cluster size, n, in a beam-gas geometry in a tandem mass spectrometer. Size dependency of the cross sections and the change of the cross sections by introduction of H to Con+ (effect of H-introduction) are explained by a statistical model based on the RRK theory, with the aid of the energetics obtained by a DFT calculation. It was found that the reactions are governed by the energetics rather than dynamics. For instance, Co3+ does not react appreciably with NO because the reactions are endothermic, while Co3H+ does because the reaction becomes exothermic by the H-introduction.

A new method that optimizes a control map of hydrocarbon (HC) addition to diesel exhaust gas for HC type Selective Catalytic Reduction DeNO x catalyst system has been developed. This method comprises a numerical model and a new optimization technique. The numerical model is capable of predicting performance of HC DeNO x with diesel fuel as a supplemental reductant. The control map of HC addition was optimized with the evolutionary programming based on the evolution of living things. As a result, NO x conversion with the optimized control map was found to be greater by 21% than that with the conventional control on Japanese 10–15 mode.

We consider the maximum 1-2 matching problem in bipartite graphs. The notion of the augmenting trail for the 1-2 matching problem, which is the extension of the notion of the augmenting path for the 1-1 matching problem is introduced. The main purpose of the present paper is to prove “the augmenting trail theorem” for the 1-2 matching problem in the bipartite graph, which is an analogue of the augmenting path theorem by Bergé for the usual 1-1 matching problems.

Catalysis of atomically precise clusters supported on a substrate is reviewed in relation to the type of reactions. The catalytic activity of supported clusters has generally been discussed in terms of electronic structure. Several lines of evidence have indicated that the electronic structure of clusters and the geometry of clusters on a support, including the accompanying cluster-support interaction, are strongly correlated with catalytic activity. The electronic states of small clusters would be easily affected by cluster–support interactions. Several studies have suggested that it is possible to tune the electronic structure through atomic control of the cluster size. It is promising to tune not only the number of cluster atoms, but also the hybridization between the electronic states of the adsorbed reactant molecules and clusters in order to realize a quantum-controlled catalyst.

A numerical model for lean NOx catalytic reaction in consideration of hydrocarbon adsorption and desorption process, which is capable of predicting the performance of diesel lean NOx catalyst using diesel fuel as a supplemental reductant, has been developed. This model is based on our simplified kinetics for the adsorption and desorption of hydrocarbons, for the oxidation of hydrocarbons, and for the reduction of NOx by hydrocarbons including the desorbed one. The adsorption of diesel exhaust hydrocarbons was expressed by the Freundlich-type isotherm that has the adsorption equilibrium constant of exponential temperature dependence. The behavior of HC and NOx reactions and HC adsorption and desorption in diesel exhaust has been simulated successfully.

Calcined sepiolite-supported Pt (Pt/CSp) catalysts indicate the high activity for complete oxidation of hydrocarbons (HC). The simultaneous oxidation of HC and SO 2 on the Fe-impregnated calcined sepiolite-supported Pt (Pt/Fe-CSp) catalysts was studied in comparison with that on Pt/CSp catalysts. There was a negligible difference in HC activity. Nevertheless, SO 2 oxidation activity on the Pt/Fe-CSp catalyst was suppressed more than that on the Pt/CSp catalyst. The calcination temperature of sepiolite affects the quantity of Fe additive. XRD and NMR show that the quantity of Fe additive depends on the distortion of the local structure of the calcined sepiolite. At the same time, the quantity of Fe additive affects the SO 2 oxidation activity. Fresh Pt/Fe-CSp catalyst absorbs SO 2 . The absorbed SO 2 reacted with Mg of CSp to form MgSO 4 on the catalyst. After this absorption was saturated, the selectivity of the oxidation was maintained. XPS and Mossbauer spectroscopy show that most of Fe on the Pt/Fe-CSp catalyst is Fe 3+ Pulsed chemisorption analysis of the redox cycle shows that Fe on the calcined sepiolite has a high oxygen storage capacity (OSC). This redox reaction suggests the mechanism of this selective oxidation reaction. The selective oxidation property is expected to be useful for a catalyst of purification for exhaust gas from a boiler or a combustion engine using a fuel which contains sulfur.

Size-selected clusters can be deposited on the surface using size-selected cluster ion beams. However, because of the cross-sectional intensity distribution of the ion beam, it is difficult to define the coverage of the deposited clusters. The aggregation probability of the cluster depends on coverage, whereas cluster size on the surface depends on the position, despite the size-selected clusters are deposited. It is crucial, therefore, to deposit clusters uniformly on the surface. In this study, size-selected clusters were deposited uniformly on surfaces by scanning the cluster ions in the form of Lissajous pattern. Two sets of deflector electrodes set in orthogonal directions were placed in front of the sample surface. Triangular waves were applied to the electrodes with an irrational frequency ratio to ensure that the ion trajectory filled the sample surface. The advantages of this method are simplicity and low cost of setup compared with raster scanning method. The authors further investigated CO adso...

Catalytic properties of simultaneously obliquely sputter-deposited platinum-metal oxide thin films were studied. We attempted to study the effect of combination of the metal oxide with platinum on the NO-CO reaction by minimizing differences in the particle size and the dispersion of platinum in the samples. Simultaneously obliquely sputter-deposited Pt-metal oxide thin film systems gave comparable particle sizes and dispersion of platinum in different combinations of several metal oxides with platinum. The catalytic property of platinum was changed by the choice of metal oxide. We found this simultaneous oblique sputter deposition to be an excellent technique for obtaining a model catalyst suitable for exploring the synergistic catalytic reaction and the role of promoters at the interfaces of different materials, which facilitates the survey of industrial catalysts.

A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitating experiments using air-sensitive samples in synchrotron radiation or other quantum beam facilities. The samples were transferred by the developed portable UHV transfer system via a public transportation at a distance over 400 km. The performance of the transfer system was demonstrated by a successful PTRF-XAFS study of Pt-4 clusters deposited on a TiO2(110) surface.

Summary A case of hydrops fetalis secondary to parvovirus B19 infection in a pregnant veterinarian is presented. To confirm transplacental infection with parvovirus B19, B19 infected erythroblast cells with intranuclear inclusions were sought and demonstrated in the chorionic villi and fetal liver by histology, electron microscopy, and in situ hybridization with B19 DNA. In addition, PCR assay showed positive viral B19 DNA in maternal and cord sera, amniotic fluid, and fetal ascites, but viral B19 DNA was negative in the sera of dogs and cats affected by parvovirus. Nevertheless, it is suggested that pregnant veterinarians may be at special risk for contracting affected animals.

Thermal stability and the effect of water-coordination of a silicoaluminophosphate, SAPO-34, were investigated on the basis of multinuclear NMR studies. Crystalline silicoaluminophosphates (SAPOs) have been found as a new family of synthetic molecular sieves. The expected applications of SAPOs are as adsorbents and catalysts. Thermal stability is one of the crucial factors in applying SAPOs as automotive exhaust catalysts. 27Al-, 29Si-, and 31P-NMR spectra and XRD as a function of temperature showed the microporous structure of SAPO-34 to be stable up to 1000°C. The effect of water-coordination on the 27A1- and 31P-NMR spectra also showed the adsorptive properties of SAPO-34 to be stable up to 1000°C. In this paper. SAPO-34 was found to be promising as an automotive exhaust catalyst with a microporous structure and high heat resistance.

Thermal stability and the effect of water-coordination of a silicoaluminophosphate, SAPO-34, were investigated on the basis of multinuclear NMR studies. Crystalline silicoaluminophosphates (SAPOs) have been found as a new family of synthetic molecular sieves. The expected applications of SAPOs are as adsorbents and catalysts. Thermal stability is one of the crucial factors in applying SAPOs as automotive exhaust catalysts. 27Al-, 29Si-, and 31P-NMR spectra and XRD as a function of temperature showed the microporous structure of SAPO-34 to be stable up to 1000°C. The effect of water-coordination on the 27A1- and 31P-NMR spectra also showed the adsorptive properties of SAPO-34 to be stable up to 1000°C. In this paper. SAPO-34 was found to be promising as an automotive exhaust catalyst with a microporous structure and high heat resistance.

Size-selected Pt(n) (n=4,7-10,15) clusters were deposited on TiO(2)(110)-(1x1) surfaces and imaged at atomic resolution using an ultrahigh-vacuum scanning tunneling microscope with a carbon nanotube tip. Clusters smaller than Pt(7) lay flat on the surface with a planar structure and a planar-to-three-dimensional transition occurred at n=8 for Pt(n) clusters on TiO(2). However, both Pt(8) and Pt(9) had two types of geometric structures. The geometric structures depend strongly on the number of atoms in the deposited cluster possibly because of the differences in binding energies in different-sized clusters and different degrees of interaction with the surface. We obtained atomic-resolution images of size-selected clusters on surfaces for the first time, enabling the identification of atomic alignments in the clusters on the surface.

The electrical properties of GaN metal–insulator–semiconductor (MIS) capacitors with as-grown SiO2, annealed SiO2, and SiNx insulators were investigated by capacitance–voltage (C–V), current–voltage (I–V), and time-dependent dielectric breakdown (TDDB) measurements. The MIS capacitor with the SiNx insulator was determined to have a lower interface trap density of 1×1011 cm-2 eV-1 than the MIS capacitors with the as-grown and annealed SiO2 insulators. In addition, the dielectric lifetime of the SiNx insulator was extrapolated to be more than 20 years at an even high voltage at room temperature. These results indicate that the high insulator/GaN interface quality and high reliability required for high-performance power devices can be achieved by the deposition of the SiNx insulator on GaN.

We report a novel method for formation of sub-nanoclusters by laser ablation at the air–liquid interface. The density of plasma induced by laser ablation at the air–liquid interface should be lower than that produced by laser ablation in liquid. In the lower density plasma, the produced clusters rarely grow or aggregate into larger clusters because the collision probability is low, resulting in the formation of small clusters. Ag sub-nanoclusters were observed by electrospray ionization mass spectrometry (ESI-MS) and X-ray photoelectron spectroscopy (XPS). These results show that low-density plasma can be applied to small-cluster formation and that laser ablation at the air–liquid interface produces a good reactive field for the formation of sub-nanoclusters. Our results highlight the importance of low-density plasma induced at the air–liquid interface for sub-nanocluster formation.

We formed an epitaxial film of CeO2(111) by sublimating Ce atoms on Ru(0001) surface kept at elevated temperature in an oxygen ambient. X-ray photoemission spectroscopy measurement revealed a decrease of Ce(4+)/Ce(3+) ratio in a small temperature window of the growth temperature between 1070 and 1096 K, which corresponds to the reduction of the CeO2(111). Scanning tunneling microscope image showed that a film with a wide terrace and a sharp step edge was obtained when the film was grown at the temperatures close to the reduction temperature, and the terrace width observed on the sample grown at 1060 K was more than twice of that grown at 1040 K. On the surface grown above the reduction temperature, the surface with a wide terrace and a sharp step was confirmed, but small dots were also seen in the terrace part, which are considerably Ce atoms adsorbed at the oxygen vacancies on the reduced surface. This experiment demonstrated that it is required to use the substrate temperature close to the reduction temperature to obtain CeO2(111) with wide terrace width and sharp step edges.

Scanning tunneling microscope observations show a geometrical transition from a planar structure to a 3D structure at n = 8. This geometrical transition resulted in a significant decrease in the activation energy of the CO oxidation reaction. The upper-layer Pt atoms of the 3D cluster structure that starts to form at n = 8 are low-coordinated Pt atoms, and they may play an important role in the CO oxidation reaction.

The electrical properties of GaN metal–insulator–semiconductor (MIS) capacitors with as-grown SiO2, annealed SiO2, and SiN x insulators were investigated by capacitance–voltage (C–V), current–voltage (I–V), and time-dependent dielectric breakdown (TDDB) measurements. The MIS capacitor with the SiN x insulator was determined to have a lower interface trap density of 1×1011 cm-2 eV-1 than the MIS capacitors with the as-grown and annealed SiO2 insulators. In addition, the dielectric lifetime of the SiN x insulator was extrapolated to be more than 20 years at an even high voltage at room temperature. These results indicate that the high insulator/GaN interface quality and high reliability required for high-performance power devices can be achieved by the deposition of the SiN x insulator on GaN.

Vertical sections of multilayers (VSM) should provide excellent testing grounds for physics and chemistry on surfaces with densely populated heterogeneous interfaces. Although VSM can be obtained from usual horizontal multilayers stacks by crushing them into pieces or by partial ion etching through masks from the top surfaces, a better way to get VSM is to form vertical multilayers. Employing simultaneous oblique deposition of ZnTe and SiO2 from opposite azimuthal directions, we have obtained nanometer-scale heterogeneous structures with anisotropie optical properties for the light coming perpendicularly to the surface. TEM revealed that successive annealing caused relaxation and recrystalllzation of ZnTe in the framework of SiO2 porous nano-structure. The resultant mosaic image of dark ZnTe regions and bright Sio2 regions of 5–10 nm wide and 30nm (or more) long told the development of VSM over the substrate although the perfect periodicity and two-dimensionality were missing. The structural modification of these quasi-multilayers was studied making reference to the similar but horizontal system of ZnTe particles periodically buried between Sio2 isolation layers.

Oblique depositlon(OD) provides an attractive anisotropic structure In nm-scale as a promising host structure to form anisotropic nm-scale composites(ANSC). Among a variety of possible methods to introduce a guest material Into the host structure of OD, we have attempted simultaneous oblique deposition of a guest and a host material from two different directions. The computer simulation for ballistic deposition, which had greatly contributed to the understanding of the morphology evolution in OD, has been carried out again here to design possible ANSC structures and to survey their variations. A typical ANSC structure obtained here is a composite of slender clusters of the guest and the host materials, which can be regarded as an anisotropic version of the well-known isotropic structures of the metal-insulator or semiconductor-insulator cermets for magneto-optical or nonlinear optical applications. This appears when the host and the guest materials are deposited from the directions of the same polar angle of 70° but from the reverse azimuthal directions. In accordance with this result, a specially designed sputtering apparatus has been constructed. Structures and optical anisotropy of the films of several composites' systems such as ZnTe-SiO2 and Cu-SiO2 formed by this apparatus have indicated that our attempt has hit the mark.

グレブナー基底を用いた整数計画のアルゴリズムとして、コンティとトラベルソのアルゴリズムが有名である。池上と楫はグレブナー基底を用いた2元線形符号の最尤復号のアルゴリズムを提示したが、それはコンティとトラベルソのアルゴリズムの類似物である。本論文の目的は計算機実験により彼らのアルゴリズムの有効性を検証することである。我々は様々なパラメータをもつ(2元)BCH符号に対して符号に付随するイデアルのグレブナー基底を計算する。ここで用いられるアルゴリズムは二つあり、一つは池上と楫による最初のアルゴリズムであり、もう一つは最近見出された改良アルゴリズムである。実験に用いる数式処理システムはAsir とSingular である。改良アルゴリズムにおいては、変数の消去計算が不要であり、最初のアルゴリズムと比べるとグレブナー基底を効率よく計算することが期待される。しかしながら、計算機実験の結果によれば、二つのアルゴリズムにはほとんど差はなかった。, There is a famous algorithm by Conti and Traverso for integer programming using the Gröbner basis in the polynomial ideal theory. Ikegami and Kaji have presented the algorithm for MLD of binary linear codes using Gröbner basis technique, which is an analogue of Conti and Traverso's algorithm. The purpose of the present paper is to verify the effectiveness of their algorithm by computational experiments. We compute the Gröbner basis of the ideals associated with (binariy) BCH codes with various parameters. The algorithms we use are two: one is the original algorithm by Ikegami-Kaji and the other is the variation of the original one, which have been developped recently. The computer algebra systems which we use are Asir and Singular. The variation of the Ikegami-Kaji algorithm which does not use the elimination, is expected to compute the Gröbner basis more efficiently than the original one. However, the result of the computational experimnets shows that there is little difference between these two algorithms.

Thermally induced structural modification of a nm-order multilayer of Mo/Si was investigated by spectral reflect-ance of soft X-rays from laser-produced plasma. Dependence of reflectivity of the nm-order multilayers on the incidence angle of soft X-rays indicated that some structural changes start to occur at 300°C and that the nm-order multilayer structures shrink at 500°C because of the formation of Mo-silicide. These results were found to be consistent with the cross-sectional transmission electron microscope observations. It is clearly shown that measurement of spectral reflectance of soft X-rays from laser plasma is a powerful method for analyzing nm-order structural modifications of multilayers.

We propose a new experimental arrangement to measure spectral reflectance of multilayer coatings in the soft X-ray region in a single laser shot, where laser-produced plasma is used as a light source. Reflectivity measurement of a Mo/Si multilayer having a 2d spacing of 24 nm is presented.

The Hamiltonian structure of M. Sato's hierarchy of higher order Kadomtsev-Petviashvili (KP) equation is derived. It is proved that KP equation is Hamiltonian equation of motion on the coadjoint orbit of a certain formal Lie group. Furthermore it possesses a family of infinitely many conserved densities which is in involution.

The complete list of the third-order polynomial evolution equations of not normal type with nontrivial Lie-Backlund symmetries is obtained. Almost all the equations appearing in the list have the hereditary recursion operator of Lie-Backlund symmetries so that the Lie algebras of their Lie-Backlund symmetries are infinite dimensional and commutative. Further, two fifth-order equations of not normal type admitting seventh-order Lie-Backlund symmetry are presented. They do not belong to the hierarchies of the third-order equations derived in the classification.

A certain super Hamiltonian formalism for evolution equations with odd variables is constructed by establishing the notion of super Hamiltonian operator. A useful criterion for the operator of the special class to be super Hamiltonian is presented, by means of which the two differential operators derived by Manin- Radul and the author from the SKP hierarchy are proved to be super Hamiltonian.

It is proved that the rank of the non-trivial polynomial conserved density of the fifth-order KdV equation is 3p−2 or 3p (p=1, 2, ...).

A Hamiltonian operator related to Sato's hierarchy of KP equations is derived. The KP equation is regarded as the Hamiltonian equation of motion on a coadjoint orbit of a certain formal Lie group.

The super Hamiltonian operator which is different from that of Manin and Radul is derived from the even order SKP hierarchy without reduction and in terms of the operator, the equation in the hierarchy is written in a Hamiltonian form.

Suppose that pn(· ; θ) is the joint probability density of n observations which are not necessarily i.i.d. In this paper we discuss the estimation of an unknown parameter u of a family of "curved probability densities" defined by M = {pn(· ; θ(u)), dim u < dim θ} embedded in S = {pn(· ; θ), θ ∈ Θ}, and develop the higher order asymptotic theory. The third-order Edgeworth expansion for a class of estimators is derived. It is shown that the maximum likelihood estimator is still third-order asymptotically optimal in our general situation. However, the Edgeworth expansion contains two terms which vanish in the case of curved exponential family. Regarding this point we elucidate some results which did not appear in Amari′s framework. Our results are applicable to time series analysis and multivariate analysis. We give a few examples (e.g., a family of curved ARMA models, a family of curved regression models).

We investigate the symmetry structure of fifth-order evolution equations and present a generalization of the potential modified Kupershmidt equation.

We investigated the effects of preparation conditions and mechanical polishing on the resistance-temperature characteristics of superconducting oxides, Y1Ba2Cu3O7-y which were prepared from different starting materials of (1) Y2O3, Ba(NO3)2 and Cu(NO3)2 (A-series) and (2) Y2O3, BaCO3 and CuO (B-series). The A-series samples were ten times more closely packed than the B-series samples. It was found that mechanical polishing of the specimen surface was necessary to obtain stable and reproducible resistance-temperature characteristics. In addition, the specimen, which was prepared from the A-series starting material, gave the best zero-resistance result at 95.5 K.

We investigated the effects of water on the superconductivity of YBa2Cu3O7-y specimens of different particle sizes and densities, which were prepared from the starting materials of Y2O3, Ba(NO3)2 and Cu(NO3)2·10H2O (referred to as specimen A) and Y2O3, BaCO3 and CuO (referred to as specimen B). The dependences of the T c and the resistance at the normal state of specimens A and B on the time stored in water were different. This is thought to be caused by the differences of the particle sizes and the densities between specimens A and B. Large crevices were observed in the surfaces of specimens A and B stored in water. This may indicate that the corrosion products from the reaction with water are soluble in water.

The XPS (X-ray photoelectron spectroscopy) spectra from (a) the cleaved surface of a single crystal, (b) the polished surface and (c) the Ar+-sputtered surface of the ceramics in Bi-Sr-Ca-Cu-O are mecnsured and compared. The chemical bond nature of Bi is the same in all three surfaces. Sr and Ca in (c) are more oxidized than those in (a). In (b), there are two kinds of Sr and Ca, one from a clean surface like the cleaved surface region, and the other, more oxidized Sr and Ca which exist in the Ar+-sputtered surface. Cu2+ is dominant in (a) and (b), while Cu+ is dominant in (c). The O 1s XPS spectrum from (c) is sharper and narrower than that from (a). This may be due to the existence of isolated metal oxides of Sr, Ca and Cu by Ar+-sputter etching.

The YBa2Cu3O x superconductors show critical temperatures at around 90 K. Although they are prepared from the different starting materials, they however exhibit similar intensities of AES spectra. For the superconductors of Bi-Sr-Ca-Cu-O and (Bi, Pb)-Sr-Ca-Cu-O, the AES intensity ratios of Ca/Sr increase when their critical temperatures increase. When the AES intensity ratios are transformed into the composition ratios using the sensitivity factor, the volume fractions of the phases of the critical temperatures (7 K, 80 K and 110 K) can be estimated from these ratios and the ideal composition ratio of each phase.