Properties of atomic intercalated carbon K4 crystals

The stability of atomic intercalated carbon $K_{4}$ crystals, XC$_{2}$ (X=H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ga, Ge, As, Se, Br, Rb or Sr) is evaluated by geometry optimization and frozen phonon analysis based on first principles calculations. Although C $K_{4}$ is unstable, NaC$_{2}$ and MgC$_{2}$ are found to be stable. It is shown that NaC$_{2}$ and MgC$_{2}$ are metallic and semi conducting, respectively

Hyperfine mixing in electromagnetic decay of doubly heavy bcbc baryons

We investigate the role of hyperfine mixing in the electromagnetic decay of ground state doubly heavy $bc$ baryons. As in the case of a previous calculation on $b\to c$ semileptonic decays of doubly heavy baryons, we find large corrections to the electromagnetic decay widths due to this mixing. Contrary to the weak case just mentioned, we find here that one can not use electromagnetic width relations obtained in the infinite heavy quark mass limit to experimentally extract information on the admixtures in a model independent way.Comment: 9 Latex pages, 4 tables. A new reference added. A few misprints correcte

Evaluation of gellan gum fluid gels as modified release oral liquids

Oral liquids are often preferred for drug administration to patients for whom swallowing is difficult, however formulating modified release versions can be challenging. A potential route to achieve modified release in oral liquids is by using fluid (sheared) gels formed by introducing a shear field during gelation in gel-forming biopolymers. These fluid gels can act as pourable viscoelastic fluids but retain true gel micro/nano structure. Here, we have demonstrated that fluid gels have potential as paediatric oral liquids preventing release of ibuprofen in simulated gastric fluid. Subsequent release at pH 7.4 was affected by the duration of exposure and magnitude of acid pH with a linear relationship between onset of release and the preceding acidic exposure duration. Delayed release was a result of increasing gel stiffness, a consequence of the acidity of the initial release media and exposure time. A much faster release rate was measured when exposure time in acid was 10 min compared with 60 min. This study highlights the potential to design fluid gels that are tuned to have a specified stiffness at a particular pH and exposure time. This could enable the preparation oral liquids with modified release behaviour

Logarithmic corrections from ferromagnetic impurity ending bonds of open antiferromagnetic host chains

We analyze the logarithmic corrections due to ferromagnetic impurity ending bonds of open spin 1/2 antiferromagnetic chains, using the density matrix renormalization group technique. A universal finite size scaling $\sim {\frac 1 {L \log L}}$ for impurity contributions in the quasi-degenerate ground state energy is demonstrated for a zigzag spin 1/2 chain at the critical next nearest neighbor coupling and the standard Heisenberg spin 1/2 chain, in the long chain limit. Using an exact solution for the latter case it is argued that one can extract the impurity contributions to the entropy and specific heat from the scaling analysis. It is also shown that a pure spin 3/2 open Heisenberg chain belongs to the same universality class.Comment: 4 pages, 7 eps figure

Twisted Superspace on a Lattice

We propose a new formulation which realizes exact twisted supersymmetry for all the supercharges on a lattice by twisted superspace formalism. We show explicit examples of N=2 twisted supersymmetry invariant BF and Wess-Zumino models in two dimensions. We introduce mild lattice noncommutativity to preserve Leibniz rule on the lattice. The formulation is based on the twisted superspace formalism for N=D=2 supersymmetry which was proposed recently. From the consistency condition of the noncommutativity of superspace, we find an unexpected three-dimensional lattice structure which may reduce into two dimensional lattice where the superspace describes semilocally scattered fermions and bosons within a double size square lattice.Comment: 49 pages, 17 figures; v2: Fig.2 is replace

Stability of complex hyperbolic space under curvature-normalized Ricci flow

Using the maximal regularity theory for quasilinear parabolic systems, we prove two stability results of complex hyperbolic space under the curvature-normalized Ricci flow in complex dimensions two and higher. The first result is on a closed manifold. The second result is on a complete noncompact manifold. To prove both results, we fully analyze the structure of the Lichnerowicz Laplacian on complex hyperbolic space. To prove the second result, we also define suitably weighted little H\"{o}lder spaces on a complete noncompact manifold and establish their interpolation properties.Comment: Some typos in version 2 are correcte

Proposing Video Editing Scheme Based on Popular Area

ウェアラブルカメラなどの記録技術の発達や映像機器の普及により，多くの場面で手軽に映像撮影を行うことが可能となった．様々な視点から撮影された映像は，撮影者本人のみならず他人にとっても有益で多くの利用可能性を秘めている．従来，日常生活やスポーツイベントでの映像に対する効果的な利用法について多くの研究が行われてきた．本論文でも，スポーツイベントにおいて複数台のカメラにより撮影される状況を研究背景とし，一般撮影者間で共有した映像データに対する切り替え方式の提案を行う．提案方式では，撮影カメラの視線に基づき人気領域の特定を行い，その領域と各カメラの位置関係による幾何学計算によって時刻ごとのカメラ選択を行う．これによりイベントにおける多数の映像撮影者の興味を考慮した映像を生成する．これを行うために各映像に対して，GPS と電子方位計より取得した位置・方向情報をメタデータとして用いる．DEWS2006 5B-i4 電子情報通信学会第17回データ工学ワークショップ 2006年3月1-3

Electrical properties of isotopically enriched neutron-transmutation-doped ^{70} Ge:Ga near the metal-insulator transition

We report the low temperature carrier transport properties of a series of nominally uncompensated neutron-transmutation doped (NTD) ^{70} Ge:Ga samples very close to the critical concentration N_c for the metal-insulator transition. The concentration of the sample closest to N_c is 1.0004N_c and it is unambiguously shown that the critical conductivity exponent is 0.5. Properties of insulating samples are discussed in the context of Efros and Shklovskii's variable range hopping conduction.Comment: 8 pages using REVTeX, 8 figures, published versio

Critical Behavior of the Conductivity of Si:P at the Metal-Insulator Transition under Uniaxial Stress

We report new measurements of the electrical conductivity sigma of the canonical three-dimensional metal-insulator system Si:P under uniaxial stress S. The zero-temperature extrapolation of sigma(S,T -> 0) ~\S - S_c\^mu shows an unprecidentedly sharp onset of finite conductivity at S_c with an exponent mu = 1. The value of mu differs significantly from that of earlier stress-tuning results. Our data show dynamical sigma(S,T) scaling on both metallic and insulating sides, viz. sigma(S,T) = sigma_c(T) F(\S - S_cT^y) where sigma_c(T) is the conductivity at the critical stress S_c. We find y = 1/znu = 0.34 where nu is the correlation-length exponent and z the dynamic critical exponent.Comment: 5 pages, 4 figure

A P2P algorithm for extraction of Gazing Area

本研究では, イベント会場などの同一時刻に近隣地域に存在する複数のカメラ付き情報端末による即席の動画共有システムを提案する. 特に注目すべき事象が存在する領域(注視領域) の探索を想定し, その処理を近傍の端末によりアドホックに構成されたP2P オーバレイネットワーク上で実行する手法について述べる. また, 各カメラの位置とその撮影領域を管理する為の基盤としてP2P ドロネーネットワークを用いる. P2P ドロネーネットワークは,アドホックに作成された簡便なネットワークから分散的な構築アルゴリズムにより構築できる. この為, 本提案システムは専用の計算機資源を用いない. 本研究で提案する手法は, 環状ネットワークの構築手法, P2P ドロネーネットワークの構築手法, 各カメラの撮影領域情報のノードへの分配手法, 各ノードで求めた共通撮影領域情報から分散的に注視領域を求める手法, 全参加ノードに対して最終的な領域を通知する手法から成る. 各カメラ付き情報端末は, GPS, 電子コンパスなどにより, 自身の撮影領域の情報を求める. 次に各ノードは撮影領域内を管理する他のノードに対して,フラッディングにより撮影領域情報を転送する. 各ノードは受け取った撮影領域情報元に, 自身の管理領域内の注視領域についての計算を行う. その後, 環状ネットワーク上で分散的に領域を撮影しているカメラ台数の最大値を求めることにより, 最も注目されている領域を求める. また, シミュレーションにより各ノードに対する計算負荷, 通信負荷についての評価を行う.DEWS2007 c8-6 電子情報通信学会 第18回データ工学ワークショップ 2007年2月28日～2007年3月2日正式版リンクwww.ieice.org/~de/DEWS/DEWS2007/pdf/c8-6.pd