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In this study, the microstructure of a base metal, and the heat-affected zone (HAZ) and weld metal of a 9Cr steel longitudinal welded tube with various internal pressure creep damage levels was studied by transmission electron microscopy and energy dispersive X-ray spectroscopy. Each portion of the steel weldment clearly changed with damage level. The present results indicate that the recovery of the microstructure is faster in HAZ than in other portions, and thus creep deformation preferentially occurs in HAZ. Moreover, it was revealed that stress accelerates the growth of M 23 C 6 precipitates as well as the reduction of dislocation density, consequently promoting recovery. It was also confirmed that the so-called type IV failure is reasonably explained by precipitate strengthening.

Possible combinations of alkali metal guest atoms and substitutional group-13 atoms in type-I Si clathrate and their thermoelectric properties were investigated using first-principles calculations. All alkali metals could be encapsulated as the guest element into a Si46 cage, and either Al or Ga was suitable for a substitutional atom. From the formation energy, possible clathrate compositions were selected as K8Al8Si38, K8Ga8Si38, Rb8Al8Si38, Rb8Ga8Si38, Cs8Al8Si38 and Cs8Ga8Si38. The thermoelectric properties of these compositions were calculated as functions of temperature and carrier density, using the Boltzmann transport equation and the calculated band energy. The obtained dependences of the Seebeck coefficient and electrical conductivity on the carrier density were discussed from the viewpoint of band structure. The thermoelectric properties were optimized to maximize ZT for each composition by controlling the carrier density. ZT μ 0.75 was predicted as the highest ZT value for hole-doped Cs8Ga8Si38. [doi:10.2320/matertrans.MBW201204]

Leucovorin (FOL) and fluorouracil (5-FU) plus oxaliplatin (l-OHP; FOLFOX) or FOL and 5-FU plus irinotecan (SN-38; FOLFIRI) are widely used as first-line chemotherapy regimens in the treatment of advanced colorectal cancer (CRC). However, second-line chemotherapy must be abandoned in certain cases due to disease progression, adverse effects or high medical cost. Therefore, the most effective regimen should be selected as first-line chemotherapy. We reported that individualization of first-line treatment (FOLFOX/FOLFIRI/Dual/Poor responder) was possible using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) and that individualized first-line chemotherapy with CD-DST may improve the prognosis of patients with unresectable CRC. The aim of the present prospective cohort study was to evaluate the individualization of first-line chemotherapy using CD-DST, with a focus on prognosis. Between March 2008 and December 2015, tumor specimens were obtained from 120 patients with CRC who had not received preoperative chemotherapy. CD-DST was performed and the growth inhibition rate (IR) was determined by exposure for 24 h with 5-FU and l-OHP (6.0 and 3.0 µg/ml, respectively) and 5-FU and SN-38 (6.0 and 0.2 µg/ml, respectively). The cumulative distribution of IR values under each condition was evaluated on the basis that the clinical response to FOLFOX and FOLFIRI is equivalent (~50%). The prognosis of dual responder was improved compared with that of poor responders, however this difference was identified to be significant. There was no different prognosis between patients treated with an appropriate first-line regimen and patients treated with an inappropriate first-line regimen in dual responders. However, in poor responders, there were significant differences of prognosis between patients treated with an appropriate first-line regimen and patients treated with an inappropriate first-line regimen (P=0.036). In conclusion, the results from the present study suggest that administration of the recommended first-line regimen using CD-DST for patients with unresectable CRC is important for the improvement of prognosis, particularly in poor responders.

To explore whether a flat-band system can accommodate superconductivity, we consider repulsively interacting fermions on the diamond chain, a simplest quasi-one-dimensional system that contains a flat band. Exact diagonalization and the density-matrix renormalization group (DMRG) are used to show that we have a significant binding energy of a Cooper pair with a long-tailed pair-pair correlation in real space when the total band filling is slightly below $1/3$, where the dispersive band interacts with the flat band that is empty but close to $E_F$. Pairs selectively formed across the outer sites of the diamond chain are responsible for the pairing correlation. At exactly $1/3$-filling an insulating phase emerges, where the entanglement spectrum indicates the particles on the outer sites are highly entangled and topological. These come from a peculiarity of the flat band in which "Wannier orbits" are not orthogonalizable., Comment: Phys. Rev. B, to be published

The microstructures of pure Zr and Zr-base alloy (Zircaloy-2) irradiated with Zr ions (self-ions) were studied by transmission electron microscopy. It was found that the c-component dislocation structures formed in neutron-irradiated Zircaloy-2 can also be obtained by self-ion irradiation. This technique can be used to simulate neutron irradiation and is thus expected to deepen our understanding of irradiation damage in pure Zr and Zr-base alloys.

For current supercomputer systems, multicore and multisocket processors are required in order to build a system, and choice of interconnection is essential. In addition, for effective development of new code, high-performance, scalable, and reliable numerical software is key. ScaLAPACK and PETSc are software developed for distributed memory parallel computer systems. Real computation requires software that is highly tuned for implementation on new architectures, such as many-core processors. In the present study, we introduce a high-performance, highly scalable eigenvalue solver with the goal of realizing the K-computer system, which is a next-generation supercomputer system. We have developed two versions of this eigenvalue solver, namely, the standard version (eigen_s) and an enhanced-performance version (eigen_sx), both of which were developed on the T2K cluster system housed at the University of Tokyo. Eigen_s uses conventional algorithms, such as Householder tridiagonalization, the divide and conquer (DC) algorithm, and the Householder backtransformation. These algorithms are carefully implemented using a blocking technique and flexible two-dimensional data-distribution in order to reduce the overhead of memory traffic and data transfer, respectively. Eigen_s performs excellently on the T2K system with 4,096 cores (theoretical peak: 37.6 TFLOPS) and exhibits fine performance (3.0 TFLOPS) with a 200,000-dimensional matrix. The enhanced version, eigen_sx, uses more advanced algorithms, such as the narrow-band reduction algorithm, DC for band matrices, and the block Householder back-transformation with WY- representation. Even though this version is still in the test stage, eigen_sxhas realized 4.7 TFLOPS with a 200,000-dimensional matrix.

The density-matrix renormalization group (DMRG) method is widely used by computational physicists as a high accuracy tool to explore the ground state in large quantum lattice models, e.g., Heisenberg and Hubbard models, which are well-known standard models describing interacting spins and electrons, respectively, in solid states. After the DMRG method was originally developed for 1-D lattice/chain models, some specific extensions toward 2-D lattice (n-leg ladder) models have been proposed. However, high accuracy as obtained in 1-D models is not always guaranteed in their extended versions because the original exquisite advantage of the algorithm is partly lost. Thus, we choose an alternative way. It is a direct 2-D extension of DMRG method which instead demands an enormously large memory space, but the memory explosion is resolved by parallelizing the DMRG code with performance tuning. The parallelized direct extended DMRG shows a good accuracy like 1-D models and an excellent parallel efficiency as the number of states kept increases. This success promises accurate analysis on large 2-D (n-leg ladder) quantum lattice models in the near future when peta-flops parallel supercomputers are available.

Yamada S, Kusumoto Y, Tokuoka Y & Yamamoto S (2011). Landform type and land improvement intensity affect floristic composition in rice paddy fields from central Japan. Weed Research 51, 51–62. Summary Paddy field agroecosystems are floristically highly diverse, but the mechanisms affecting this diversity are not clear, especially at broad spatial scales. To conserve paddy weed species, we aimed to clarify the importance of landscape-scale variables for in-field floristic diversity. Statistical evidence of the shape of the species response along environmental gradients was obtained by Detrended Correspondence Analysis, DCA. Predicted variables were landform type (narrow valley floor, wide valley floor, old river channel, meander plain with dry soil and meander plain with wet soil), intensity of land improvement (six classes) and species attribute. Both landform type and land improvement intensity were important in explaining variations in in-field floristic diversity. Non-paddy weeds and rare threatened species occurred frequently in unimproved plots. Plots in the narrow valley floor and old river channel landform categories had representative species that were categorised as threatened. Unimproved plots also had representative species that were categorised as threatened. The threatened representative species in unimproved plots were confined to old river channels. Unimproved plots in old river channels were the most vulnerable in terms of conservation. Estimation of floristic patterns in paddy fields using landform type and land improvement intensity could be a useful tool for maintaining floristic diversity.

管理されたクロマツ二次林の林床植生の復元にあたり，刈り取り残渣を用いることの有効性を把握すべく，刈り取り残渣の撒き出し実験を行った。地上植生の出現種のうち刈り取り残渣から発芽した種の割合は約30％と低かったが，地上植生で開花結実が確認された種の約60％は刈り取り残渣から確認された。刈り取り残渣には，発芽個体密度は既往文献より低かったものの，多種の草原生種が含まれた。地上植生と比較して，刈り取り残渣から発芽した樹林生種の種数は顕著に少なく，林外の人為攪乱地に生育する雑草種の密度は低かった。植生復元材料として刈り取り残渣を用いる際には，草原生種，樹林生種といった種群に応じて復元地へ導入しうる種の割合が異なることを踏まえ，より多数の復元対象種を再生すべくさらに研究を進める必要がある。

Uncultivated periods are important in rice paddy fields for the survival of species favoring unaerated soils. Clarifying the mechanisms affecting the floristic diversity of in-field habitats is a key part of sustainable agriculture. We hypothesized that the timing of crop harvest influences the flora in the subsequent uncultivated period in rice paddy fields. To confirm this hypothesis, surface soils were sampled in cultivated paddy fields at the beginning of August.The sampled soils stored in ≤ 5% relative light intensity were exposed to direct light at different periods varied from late August to the beginning of October. Germinated seedlings were counted until spring the next year. Observation in autumn showed that the numbers of species, germinated individuals, and flowering individuals differed as a function of the duration of light exposure, although these differences were less clear in the subsequent spring. These differences can be explained by differences in ecological traits such as maturation rate and optimum germination temperature. Timing of the rice harvest is closely linked to the timing of rice planting, which in turn can affect the germination of species maturing before the rice is planted.

In order to explore a superconducting mechanism on iron-based superconductors, we numerically study a two-band minimal model considering two degenerate d xz and d yz orbitals on Fe atom. We perform exact diagonalization on a two-band and two-leg square ladder totally composed of 10 lattice sites, which is computationally equivalent to 4-leg 20-sites square-Hubbard-ladder. Consequently, we find that a robust pairing occurs in a wide parameter range when the intra-orbital repulsive interaction becomes smaller than the inter-orbital one. Moreover, the obtained binding energy can grow into much larger value than that obtained in the single band Hubbard model depending on the parameter range.

In order to examine the ground state of the single-band Hubbard model from a slightly doped region to an overdoped one, we use the density renormalization group method extended directly to the ladder model and obtain hole profiles with changing the on-site repulsion and the doping ratio. The calculation results in a heavily underdoped region, in which one and two holes (up and down spins) are added, reveal that an attractive interaction works between holes which are confined inside a stripe shape pattern while strong disorders separate the two holes. When doping holes further within an underdoped range, the stripes formed by two holes merge and various stripe structures appear depending on U/t and the doping ratio. The remarkable finding in the underdoped region is a stripe formation composed of 4 holes analytically predicted by Chang and Affleck. On the other hand, in the overdoped range the stripe-like shape becomes very simple, i.e., only a small oscillating charge density profile emerges. These rich features in the underdoped range are relevant to electronic inhomogeneities experimentally observed in high-Tc superconductors, while those are directly observable in atomic Fermi gases loaded on optical lattices.

We numerically study quantum effects in intrinsic Josephson junctions of layered high- T c superconductors in order to explain recent experimental observations on the switching rate enhancement in the low temperature quantum regime. We pay attention to the capacitive coupling between neighboring junctions and perform simulations for the Schrodinger equation derived from the Hamiltonian describing the capacitive coupling. The simulation results reveal that the phase dynamics show synchronous behaviors when entering the quantum regime. This is qualitatively consistent with the experimental result.

In order to study the vortex core electronic structure in high- T c superconductors, we examine 1-D Hubbard model with trap potential by using the density matrix renormalization group method. Instead of directly treating the vortex, the approach mimics the carrier density depression inside the vortex core via the trap potential and exactly calculate strong correlation effects on the depressed region. Consequently, we find that the Mott state emerges in the central region and the metallic edge surrounds the Mott region. Furthermore, when adding spin imbalance, the calculations reveal that a local antiferromagnetic order covers the Mott state region, and moreover, the antiferromagnetic order modulates with a long periodicity. We expect that these results closely relate to the vortex core electronic structure while their calculation results can be directly compared with atomic Fermi gases loaded on an optical lattice.

In order to study the ground state of the Hubbard model from a slightly doped region to an over-doped one, we directly apply the density renormalization group method to 4-leg × 20-ladder repulsive Hubbard model and calculate hole distribution profiles with changing the on-site repulsion U / t from 0 to 15 and the doping ratio from 0.025 to 0.250. The calculation results in the underdoped range reveal that various stripe structures formed by doped holes merge or separate depending on U / t and the doping ratio. We suggest that these rich features are relevant to modulated hole distributions as experimentally observed in underdoped high-Tc superconductors.

We study one-dimensional and 3-leg ladder repulsive Hubbard models with random potential by using the density-matrix renormalization group method. When holes are slightly doped to the half-filling, the local Mott phase called “Mott plateau” and the local dip structure in density profile called “hole localized valley” are well-separately observable in strong on-site repulsive U / t and strong randomness for both models. We suggest that these separated structures qualitatively capture locally inhomogeneous characters seen in heavily under-doped High- T c superconductors.

Agricultural landscapes with spatial and temporal variations interact with each other to affect the existing biodiversity. Though rice fields provide important habitats for birds all over the world, studies so far have rarely explored the effects of landscape heterogeneity on bird species in rice paddy areas. This study investigated the effects of habitat cover and landscape variables on the species richness and the abundance of birds in rice paddy areas in Japan. Data on bird occurrence and the environment were collected at 32 grid squares (1 × 1 km) in the Tone River basin. The richness and the abundance of agricultural wetland species were particularly high in landscapes with large areas of rice fields in summer, when rice fields were irrigated, but in those with large areas of open water in winter, when rice fields were drained. It is important to maintain a combination of rice fields and open water to satisfy multiple habitat requirements by agricultural wetland species throughout the year. Grassland species were positively associated with a rich diversity of land cover including fallow fields and open water, indicating the importance of a simultaneous existence of multiple landscape elements. Forest cover in landscapes positively affected edge species and woodland species. Since forest cover had a relatively strong correlation with edge density, the responses of bird species to changes in forest cover and edge density need to be explored further. This study illustrates the importance of spatial and temporal landscape complementation for bird species in rice paddy areas.

We investigate quantum dynamics of the superconducting phase in intrinsic Josephson junctions of layered high- T c superconductors motivated by a recent experimental observation for the switching rate enhancement in the low temperature quantum regime. We pay attention to only the capacitive coupling between neighboring junctions and perform large-scale simulations for the Schrodinger equation derived from the Hamiltonian considering the capacitive coupling alone. The simulation focuses on an issue whether the switching of a junction induces those of the other junctions or not. The results reveal that the superconducting phase dynamics show synchronous behavior with increasing the quantum character, e.g., decreasing the junction plane area and effectively the temperature. This is qualitatively consistent with the experimental result.

In order to study an interplay between electronic inhomogeneity and superconductivity as seen in high-Tc cuprates, we numerically examine attractive Hubbard model in the absence of the translation symmetry. We systematically calculate the particle density profile for both 1-D and 2-D attractive Hubbard models with harmonic potential wells using the exact diagonalization and the density-matrix renormalization group methods. The numerical results reveal that fine inhomogeneous zig-zag patterns universally emerge in the 1-D model case and the zig-zag structure becomes checkerboard type in the 2-D one. Moreover, it is numerically and theoretically found that such inhomogeneities are caused by double occupation component, i.e., pairs tightly bound on a site.

Background In 2007, we began using the anorectal line (ARL) as the landmark for commencing rectal mucosal dissection (RMD) instead of the dentate line (DL) during laparoscopy-assisted transanal pull-through (L-TAPT) for Hirschsprung's disease (HD). We conducted a medium-term prospective comparison of postoperative fecal continence (POFC) between DL and ARL cases to follow our short-term study. Methods POFC is assessed by scoring frequency of motions, severity of staining, severity of perianal erosions, anal shape, requirement for medications, sensation of rectal fullness, and ability to distinguish flatus from stool on a scale of 0 to 2 (maximum: 14). Results Patient demographics were similar for ARL (2007–2014: n = 33) and DL (1997–2006: n = 41). There were no intraoperative complications and 2 cases of postoperative colitis in both ARL (6.1%) and DL (4.9%). Mean annual medium-term POFC scores for the 4–7 term of this study were consistently better in ARL: 9.7 ± 1.4*, 10.1 ± 1.6*, 10.6 ± 1.6, and 11.3 ± 1.4* in ARL and 8.6 ± 1.5, 9.1 ± 1.6, 9.8 ± 1.9, 10.0 ± 1.6 in DL (*: p Conclusions Medium-term POFC is better when the ARL is used as the landmark for RMD during L-TAPT for HD.

Objectives: To compare the effects of tocilizumab (TCZ) plus methotrexate (MTX), etanercept (ETN) plus MTX, and infliximab (IFX) plus MTX, respectively on arterial stiffness in rheumatoid arthritis (RA) patients despite MTX treatment, in an open-label, randomized study. Methods: 62 RA patients with moderate to severe active disease despite MTX treatment were randomly assigned to receive TCZ plus MTX (n=21), ETN plus MTX (n=21), or IFX plus MTX (n=20). All patients have no previous history of CV. Arterial stiffness was assessed with cardio-ankle vascular index (CAVI) and augmentation index corrected for a heart rate of 75 beats per minute (AIx@75) at baseline and 24 weeks follow-up. Clinical data were collected at regular visits. Results: The characteristics of each group at baseline were not significantly different. In all groups there was significant attenuation from baseline to 24 weeks follow-up in CAVI(TCZ: p=0.01; ETN: p=0.03; IFX:p=0.02) and in AIx@75 (TCZ: p=0.01; ETN: p= 0.03; IFX: p=0.02). There were no significant differences between each group in measures of CAVI (p=0.53) or AIx@75 (p=0.55). There were no significant changes in cardiovascular risk factors either within or between groups. Conclusions: Therapy of TCZ, ETN, or IFX combined with MTX, reduced arterial stiffness in RA patients. These findings suggest that combination therapy to block IL6 with MTX not only reduced RA disease activity but also limited vascular damage in patients with RA by blocking TNF.

We explore a novel type of pairing in the repulsive Hubbard model with a confinement potential. Such an undertaking situation including the confinement potential is realized in a part of intense spatial modulations observed in High- T c cuprate superconductors, while an atomic Fermi gas loaded on an optical lattice is described by the Hubbard model with the confinement potential. In this paper, applying the exact diagonalization method to a one-dimensional Hubbard model with the confinement potential, we find that, when U exceeds a critical value, the binding energy of two Fermi atoms becomes ‘negative, indicating that an attractive interaction effectively works between two fermions. In this case, a ‘Mott core’ appears in the confinement center, where each site is occupied by one atom, and the Cooper-pair function strongly develops between fermions in the left and right hand sides of this core.

本論文では前方車両回避運動を対象とし, PWLモデルに基づきドライバーの運転行動のモデル化を行った. 走行データは, 3次元没入型VR装置であるCAVEを用いたドライビングシミュレータにより収集した. データクラスタリング手法とサポートベクターマシンを組み合わせ, PWL形式として運転行動を表現することで, 前方車両回避時における運転行動の動作と判断の両側面の推定を行った.

We investigated the influence of management and micro-scale landform on the species composition and richness of ground flora in secondary woodlands and their verges next to paddy fields in the Tama Hills, Tokyo, Japan. Sites representing various micro-scale landforms and different management regimes were sampled. The results of Detrended Correspondence Analysis and Indicator Species Analysis showed that there was no significant difference between management regimes on species composition in head hollow sites. However, species composition was unique in other landform types having the same management regimes. Micro-scale landform units had less effect on species composition than management regime on crest slopes and side slopes of secondary woodlands. A large variation in species composition of verges, all on the lowermost side slopes, was found within sites, but the composition was different when compared with other sites. We recognized five habitat types associated with species composition that resulted from the combined effects of landform and management regimes. Among habitat types, the verges and the well-managed woodlands had high species richness. Management practices within woodlands have enhanced the species richness on crest slopes and side slopes. High beta diversity of ground flora could be due to the variation in micro-scale landform along soil moisture regimes. Intensive management involving clear-cutting on the lower side slopes (an ecotone of mesic and wet environments) accompanied by paddy cultivation on valley bottoms enhanced the diversity of herbaceous vegetation in the verges.

Embankments or levees of each paddy lot found in traditional agricultural landscapes have been focused as semi-natural grassland habitats with high species richness. In case of Yatsuda landscapes in hills, although there are several embankments or levee types, secondary forest verges to paddy fields on lowermost hillside-slopes are an important habitat not only for grassland plants but for well-managed forest species. We researched floristic compositions of the verges in the Kitsuregawa Hills, and understood how the differences of upslope forest vegetation and geomorphologic properties affect the species composition. In results, herbaceous vegetation of the verges consisted of several habitat-type plants such as specific species of forests and their margins, wetlands and grasslands. Species composition was drastically different in between valley-head-domain verges and crest-slope-domain ones. We concluded forest verges to paddy fields in hills were strongly influenced by upslope forest vegetation, and furthermore by periodic mowing: these could make species richness high.

The structural characteristics of crystalline germanium nanoparticles prepared by an evaporation method were investigated by transmission electron microscopy and electron energy-loss spectroscopy. Fivefold multiply twinned particles with diameters as fine as 7 nm were found; the misfit angle caused by symmetry is compensated by lattice distortion without introducing lattice defects. It is clarified that both the quantum size effect and lattice distortion occur in particles with 12–20 nm diameter. Due to distortion, the unit cell volume of these particles is compressed to 94% of that for bulk, on average. It was also found that the diamond structure is stable when the particle diameter is as small as approximately 2 nm.

In this study, we investigated the most suitable extensive cultivation management cycle for conserving floral diversity in a fallow paddy field. The following three studies were made for this purpose:(1) review of the examples of paddy restoration (2) vegetation survey of fallow paddy fields and (3) rhizome study of Phragmites australis. The paddy restoration works involve those aboveground and underground i.e. mowing and plowing. The following two types of plants were found to interfere with mowing: tall-stem plants (e.g. Phragmites australis and Miscanthus sacchariflorus) and rhizome and erect-stem plants (e.g. Isachne globosa and Leersia sayanuka). These plants increased greatly during the second year in fallow. In plowing, plants with strong and long rhizome (e.g. P. australis and M. sacchariflorus) were found to interfere. The weight of their rhizome increased greatly during the forth year in fallow. Plowing is four-times laborious compared to mowing in restoration work. Therefore it is suggested that cultivation of once every four years is effective in restoration from the labor point of view.

Spheroidal graphite cast irons are widely used for auto parts because they have large degrees of freedom in shape and are inexpensive. When they are welded, however, they show serious drawback of crack generation due to excess carbon at thehardened region of heat-affected zone. We have studied on decarburized spheroidal graphite cast iron which has a possibility of welding because of graphite free in the surface region. In the present study, some characteristics of the decarburized layer in the spheroidal graphite cast iron were investigated. The results obtained are as follows. Growth of decarburized layer is controlled by diffusion of carbon atoms toward the surface region in the iron during the heat-treatment and there is a critical temperature of 930 K for the decarburization, below which decarburization does not occur. When the area ratios of the decarburized layer to whole sectional area in the rod-shaped tensile test specimen was defined to be a ratio of decarburized layer, the tensile strength of the specimen scarcely influenced by the ratio of decarburized layer. However, when the overdecarburization was processed, the tensile strength showed a tendency to decrease. Therefore, it should be noted in practical use of the decarburized spheroidal graphite cast iron that the excessive decarburization makes the strength of thin parts of the iron to decrease.

We study the dynamical properties of ultracold fermions in one-dimensional optical superlattices by using the adaptive time-dependent density matrix renormalization group method. The system is repulsive Hubbard model with an two-site periodic superlattice potential. Owing to superlattice structure, the ground-state states become the Mott-type insulating state at quarter-filling and band-type insulating state at half-filling, respectively. We clarify the dynamical properties of time evolution when the system is non-adiabatically changed to another lattice structure (i.e., the superlattice potential is suddenly changed to a normal one). In the case of Mott-type insulating state at quarter-filling, the time evolution exhibits a profile similar to that expected for single atom. On the other hand, we clarify the dynamical properties of a band-type insulating state at half-filling. The strongly-correlated interaction an unusual pairing of fermions induced the pair hopping process. We further address the robustness of pair hopping process and possibility of superconductivity by using sudden change from superlattice structure to normal one.

We study a multi-orbital Fermi gas loaded on a one-dimensional optical lattice with harmonic trap potential. We show that this multi-orbital gas contains various quantum phases, i.e., (i) the ferromagnetic phase in large on–site interaction and (ii) the Haldane phase at half filling. Furthermore, our density-matrix renormalization-group simulations lead to systematic studies about the ground state, varying on–site interaction, spin imbalance, and total particle number, under spatial inhomogeneity originating from the trap potential. This trap potential produces a rich phase structure. In a metallic region, the phase-separated ferromagnetism appears, whereas in a central Mott core the Haldane phase is found. One of the remarkable features is that the ferromagnetic metal phase behaves as the edge state of the Haldane phase when these two phases coexist.

We examine quantum phases emerging from the double degeneracy of $p$-orbital bands in attractive atomic Fermi gases loaded on a one-dimensional (1D) optical lattice. Our numerical simulations via the density-matrix renormalization group predict the emergence of a state with a charge excitation gap, namely the Haldane insulator phase. A mapping onto an effective spin-1 model reveals its physical origin. Moreover, we show that population imbalance leads to richer diversity of the quantum phases, including a phase-separated polarized state. Finally, we study the effects of the harmonic trap potential in this 1D chain.

This paper reports the performance of Eigen-G, which is a GPU-based eigenvalue solver for real-symmetric matrices. We confirmed that Eigen-G outperforms state-of-the-art GPU-based eigensolvers such as magma_dsyevd and magma_dsyevd_2stage implemented in the MAGMA version 1.4.0. Applying the best-tuned CUDA BLAS libraries and the GPU-CPU hybrid DGEMM yields an even better performance improvement. We observe an approximately 2.3 times speedup over magma_ dsyevd on a Tesla K20c.

By using the density-matrix renormalization-group method, we study impurity effects on the pair correlation function of the one-dimensional spin-imbalanced Anderson–Hubbard model. In strongly-attractive interacting cases in the presence of weak random potentials, we find that the Fulde–Ferrell–Larkin–Ovchinnikov type pair correlation function with nodes decays slower than that of Bardeen–Cooper–Schrieffer type one without nodes. This means that the former type pairing is unexpectedly more robust against randomness in the strong coupling regime.

Plasmon energies near a cubic-ZrO2 (c-ZrO2)/α-Al2O3 interface were studied by electron energy loss spectroscopy using a field-emission transmission electron microscope. The plasmon energies measured by scanning an electron probe of 1 nm in diameter across the interface showed that, approaching the interface, the plasmon energy of c-ZrO2 increases from 23.9 to 24.3 eV and that of α-Al2O3 decreases from 24.3 to 23.4 eV. Energy dispersive x-ray spectroscopy revealed that fluctuation of the chemical composition across the interface is small (⩽5%) and causes only a slight change in the plasmon energies (⩽0.16 eV). We conclude that the large energy changes (up to 0.9 eV) are mainly caused by lattice distortion. Using the Drude model, it was found that, 3 nm from the interface, the unit cell volume of c-ZrO2 decreases by 3% and that of α-Al2O3 increases by 6% compared with the volumes at 50 nm. The presence of lattice distortion near the interface was also confirmed by the convergent-beam electron diffraction me...

Succession and the number of species were investigated in wet, abandoned paddies, undergoing various treatments (mowing once or twice a year, plowing, and surface soil padding) in the Tama Hills (western Tokyo). Phragmites acstralis was dominant before such management was performed in these paddies. In plowed plots, most of the P. australis disappeared. In padded plots, in addition to P. australis, other dominant species such as Isachne globosa and Polygonum thunbergii also disappeared, and erect stem paddy-weeds became dominant. In mowed plots, the density of P. australis gradually decreased with increasing mowing frequency, and prostrated or rhizome paddy-weeds increased. The number of species in the plots mowed once was sometimes higher than that in the plots mowed twice.

To evaluate the tumour imaging potential of fluorine-18 fluoromisonidazole (FMISO), we studied FMISO uptake in an experimental tumour model and examined the correlation between intratumoral distributions of FMISO, 14C-2-deoxyglucose (2DG) and 14C-methionine (Met). The study was performed using control rats with the AH109A tumour and rats with the same tumour under local hypoxia. Tumour uptake of FMISO was constant between 30 min and 2 h after injection, and the tumour to muscle ratio was 2 from 2 to 4 h. A tumour study with FMISO was scheduled at 2 h. Double-tracer autoradiography of the tumour demonstrated that in the areas of high FMISO uptake, there was low uptake of Met, while areas of low FMISO uptake showed high Met uptake. FMISO showed high grain density in the rim of the tumour surrounding the necrotic area. 2DG showed a more uniform distribution over the entire section of viable cells. The mean uptake of FMISO by hypoxic, radioresistant tumours was significantly higher than that by the control tumours (P

We numerically investigate a dependence of pairing interaction strength on quantum coherence and related tunneling dynamics in order to clarify whether the strong pairing interaction suppresses quantum coherent characters. The simulation is performed by using the attractive Hubbard model with double well potential. The simulation result reveals that the tunneling dynamics between the separated wells is dramatically suppressed with increasing the pairing interaction. This fact implies that the pair coherence is easily lost under randomness when the pairing interaction becomes very strong. We claim that such an issue is related to the loss of the pair coherence in under-doped High- T c superconductors. In addition, we note that the tunneling dynamics can be directly confirmed by using the crossover from BCS to BEC in atomic Fermi gases.

We numerically study the repulsive Hubbard model with random potential by using the density-matrix renormalization group method. When a few holes are doped to the half-filling, i.e., in slightly doped Mott insulator, we clearly find that “Mott plateaus” and “hole localized valleys” well-separately form in strong on-site repulsive U / t and strong randomness. These nano-scale structures are non-trivial ones created due to strong correlation incorporating randomness. We suggest that these structures qualitatively capture phenomena seen in heavily under-doped high- T c superconductors, while cold atomic Fermi gases loaded on an optical lattice can experimentally confirm the structures under a well-controllable manner.

固相重合によって共役鎖構造を形成するジアセチレン単分子膜の表面形態を水面上で直接観察した. これまで, 水面上の単分子膜観察は困難であったが, 光学系に工夫を施すことによって, 微分干渉・偏光顕微鏡などの光学的手段を用いることが可能となった. その結果, 展開する溶液の濃度や展開する水面の面積などによって, 表面形態は著しく影響を受けることがわかった. また, 高濃度の展開溶液をせまい領域にトラップし, そのあとで水面の面積を拡大していく手法によって溶液の水面上での拡散を制御し, 大面積の帯状単結晶ドメインを成長させることができた. さらに, 紫外線を照射した際にポリマー単分子膜から偏光した蛍光が放射されることを利用して, 共役鎖方向や単位胞の配置などを決め, 膜構造のモデルを作製した. また, 紫外線重合の際の雰囲気を, 空気およびアルゴンガスで比較した結果, 重合時の表面形態変化には酸素が大きく影響していることがわかった.

The presence of silicon nanotubes (SiNTs) composed of rolled-up quasi-two-dimensional honeycomb nets was first revealed by transmission electron microscopy, energy dispersive X-ray spectroscopy, and electron diffraction analysis, among products synthesized using a simple laser ablation technique. They were coaxial multiwall high-purity SiNTs with cylindrical symmetry, smallest inner and outer diameters of 1 and 4 nm, respectively, lengths up to ~1 µm, and an interwall distance of 0.36 nm.

A high-performance SYMV kernel is implemented on Fermi-core GPUs using an atomic-operation based algorithm. The algorithm is effective for the memory bandwidth and reduced memory usage. On a Tesla C2050, sustained double-precision and single-precision performances of approximately 43 GFLOPS and 78 GFLOPS, respectively, were achieved. The proposed SYMV kernel also performs on a GeForce GTX580 with 72 GFLOPS and 128 GFLOPS in the double-precision and single-precision modes, respectively. The proposed SYMV kernel outperforms major CUDA BLAS kernels, CUBLAS, MAGMABLAS, and CULA-BLAS. This performance improvement has a significant impact when the SYMV kernel is plugged into user codes.

Mediastinal masses include a wide variety of tumours and remain an interesting diagnostic challenge for radiologist. We performed positron emission tomography (PET) studies of primary mediastinal tumours in order to predict the malignancy of these tumours preoperatively. Twenty-two patients with primary mediastinal tumours were studied with PET using 2-deoxy-2-[18F]fluoro-D-glucose (FDG). The histological findings of surgical pathology or biopsy, or mediastinoscopy were compared with those of computerised tomography (CT) and PET. PET images were evaluated semiquantitatively using the differential uptake ratio (DUR). Increased FDG uptake was observed in nine of ten patients with malignant tumours, including thymic carcinomas, lymphomas, invasive thymomas and a case of sarcoidosis. A moderate level of FDG uptake was found in a myeloma, non-invasive thymomas, and a schwannoma, whereas a low uptake was observed in a teratoma and various benign cysts. The mean FDG uptake of malignant tumours was significantly higher than that of benign tumours. Both thymic cancer and invasive thymoma showed a high FDG uptake. CT examination resulted in three false-negative and two false-positive cases when used in predicting tumour invasion, while PET was associated with a false-positive and a false-negative case. In conclusion, the use of FDG with PET is clinically helpful in evaluating the malignant nature of primary mediastinal tumours. Our results also suggest that a high FDG uptake reflects the invasiveness of malignant nature of thymic tumours. Images Figure 1 Figure 2

The effects of guest atomic species in Si clathrates on the lattice thermal conductivity were studied using classical molecular dynamics calculations. The interaction between a host atom and a guest atom was described by the Morse potential function while that between host atoms was described by the Tersoff potential. The parameters of the potentials were newly determined for this study such that the potential curves obtained from first-principles calculations for the insertion of a guest atom into a Si cage were successfully reproduced. The lattice thermal conductivities were calculated by using the Green-Kubo method. The experimental lattice thermal conductivity of Ba8Ga16Si30 can be successfully reproduced using the method. As a result, the lattice thermal conductivities of type-I Si clathrates, M8Si46 (M = Na, Mg, K, Ca Rb, Sr, Cs, or Ba), were obtained. It is found that the lattice thermal conductivities of M8Si46, where M is IIA elements (i.e., M = Mg, Ca, Sr, or Ba) tend to be lower than those of M...

In order to examine in vivo effects of irradiation on tumor uptake ofl-[methyl- 11 C]methionine at a cellular level, the distribution ofl-[methyl- 14 C]methionine (Met) in a rat AH109A tumor model was investigated using microautoradiography. Silver grain density of tumor cell layer decreased rapidly within the first day after 20 Gy of irradiation, and continued to fall during day 2. Grain density of granulation tissue was 25% of tumor cells and was unchanged after irradiation. Macrophages and necrotic tissue showed low grain density and a small post-irradiation decrease. One day after irradiation, tumor cell showed giant cell formation and decreased cell density per unit area. The number of grains was greater in giant tumor cells than in non-irradiated tumor cell. Rapid response of Met uptake by tumor cells without a significant uptake by granulation tissue and macrophages suggest that 11 C-Met is a suitable tracer for monitoring tumor radiotherapy with positron emission tomography.