Growth and characterization of GaInNAs by molecular beam epitaxy using a nitrogen irradiation method

We propose an innovative technique, making use of the In segregation effect, referred as the N irradiation method, to enhance In-N bonding and extend the emission wavelength of GaInNAs quantum wells (QWs). After the formation of a complete In floating layer, the growth is interrupted and N irradiation is initiated. The majority of N atoms are forced to bond with In atoms and their incorporation is regulated independently by the N exposure time and the As pressure. The effect of the N exposure time and As pressure on the N incorporation and the optical quality of GaInNAs QWs were investigated. Anomalous photoluminescence (PL) wavelength red shifts after rapid thermal annealing (RTA) were observed in the N-irradiated samples, whereas a normal GaInNAs sample revealed a blue shift. This method provides an alternative way to extend the emission wavelength of GaInNAs QWs with decent optical quality. We demonstrate light emission at 1546 nm from an 11-nm-thick QW, using this method and the PL intensity is similar to that of a 7-nm-thick GaInNAs QW grown at a reduced rate. (C) 2008 Elsevier B.V. All rights reserved.

Syntheses and reactions of heterometallic complexes of nickel and copper with tetrathiotungstates. The molecular structures of [Ph(4)P](2)[S2W(mu-S)(2)Ni(S-2)] and W(mu-S)(4)Cu-2(PPh(3))(4)center dot py

Reaction of [Ph(4)P]2WS4 With NiCl2 in methanol solution in the presence of NaOCH3 leads to the formation of [Ph(4)P](2) [S2W(mu-S)(2)Ni(S-2)] (I) A Similar reaction between (NH4)(2)WS4 and NiCl2 under O-2 atmosphere in the presence of Ph(4)PCl or (n)Bu(4)NCl affords [Ph(4)P](2)([(S-2)W(O)(mu-S)(2)]Ni-2] (IIa) and [(n)Bu(4)N](2)([(S-2)W(O)(mu-S)(2)]Ni-2} (IIb) Under argon the same reaction gives [Ph(4)P](2)[Ni(WS4)(2)] (IIIa) and [(n)Bu(4)N](2)[Ni(WS4)(2)] (IIIb). [Ph(4)P](2)[Ni(WOS3)(2)] (IV) and [Ph(4)P](2)[Ni(WO2S2)(2)] (V) can be prepared from the reaction of [Ph(4)P]2WOS3 and [Ph(4)P]2WO2S2 with NiCl2. Treatment of (NH4)(2)WS4 with CuCl in the presence of PPh(3) in boiling pyridine produces W(mu-S)(4)Cu-2(PPh(3))(3) (VI), which can further react with excess PPh(3) to give W(mu-S)(4)Cu-2(PPh(3))(4) . py (VII). Complex I crystallizes in the space group P2(1)/n with the cell parameters: a = 20.049(4), b = 17.010(4), c = 14.311(7) Angstrom; beta = 110.24(3)degrees and Z = 4; R = 0.058 for 4267 independent reflections. The structural study confirms that complex I contains two terminal sulfide ligands, two bridging sulfide ligands, a side-on disulfide ligand, and a planar central W(mu-S)(2)Ni four membered ring. Complex VII crystallizes in the space group C2/c with the cell parameters: a = 26.436(8), b = 20.542(6), c = 19.095(8) Angstrom; beta = 125.00(3)degrees and Z = 4; R = 0.080 for 3802 independent reflections. The structural study reveals a perfect linear arrangement of the three metal atoms Cu-W-Cu.

[Book review] Collaborative learning in mathematics

Review of: Collaborative Learning in Mathematics: A challenge to our beliefs and practices by Malcolm Swan, National Institute of Adult Continuing Education, paperback £24.95, ISBN 981-1-86201-311-7; hardback £44.95, ISBN 978-1-86201-316-2.

The importance of validating the diagnosis of coronary heart disease when measuring secondary prevention:a cross-sectional study in general practice

To compare levels of recorded risk factors and drug treatment between patients with validated and non-validated diagnoses of coronary heart disease (CHD) in Northern Ireland.

La Religion en Chine : exposé des trois religions des Chinois; (suivi) d'Observations sur l'état actuel et l'avenir de la propagande chrétienne parmi ce peuple / par le Révérend Dr J. Edkins D.D.,... ; trad. de l'anglais... par L. de Milloué,..

Titre original : Religion in China

La escritura de una historia : lectura de Bernal y de la conquista.

Expone un intento de lectura e interpretación de lo que en realidad significó aquel tipo de escritura nueva en relación con la aparición del nuevo mundo.Se basa en el planteamiento fundamental de que hoy existe suficiente documentación bibliografía como para poder encarar tales hechos con una objetividad mucho mayor de lo que ocurría en la vieja tradición del nacionalismo hispánico o de la leyenda negra.En definitiva, expone un análisis interpretativo y textual de la obra 'La Historia verdadera de la Conquista de la Nueva España' de Bernal Díaz del Castillo poniéndolo en relación con la historiografía literaria indiana de los siglos de oro y la literatura colonial de en América.

[Cardiogenic and non cardiogenic pulmonary edema: pathomechanisms and causes]

The development of pulmonary edema is divided in cardiogenic and non-cardiogenic. Cardiogenic edema pathogenically is caused by elevated hydrostatic pressure in the pulmonary capillaries due to left sided congestive heart failure. Non-cardiogenic pulmonary edema is categorized depending on the underlying pathogenesis in low-alveolar pressure, elevated permeability or neurogenic edema. Some important examples of causes are upper airway obstruction like in laryngeal paralysis or strangulation for low alveolar pressure, leptospirosis and ARDS for elevated permeability, and epilepsy, brain trauma and electrocution for neurogenic edema. The differentiation between cardiogenic versus non-cardiogenic genesis is not always straightforward, but most relevant, because treatment markedly differs between the two. Of further importance is the identification of the specific underlying cause in non-cardiogenic edema, not only for therapeutic but particularly for prognostic reasons. Depending on the cause the prognosis ranges from very poor to good chance of complete recovery.

新興民主主義の不安定 -- 勝利連合の変更と制度からの逸脱

本稿は，新興民主主義の不安定化を，民主化による勝利連合の変更から説明しようとするものである。基本として民主主義体制における政治的不安定は，主要な政治的プレーヤー，具体的には，権力者もしくは権力外主体の２者のいずれかが，民主主義制度から逸脱しようとするインセンティブを持つ状態だと考える。ここで権力外主体の逸脱行為に焦点を当てた場合，不安定化は権威主義体制期に権力を支えた勝利連合が民主化後，勝利連合から外れ，新しい政策傾向に不満を持つことによって発生すると考えられる。権力外主体の不満が，自らの勢力規模との関係である閾値を越えたとき，制度外行動による権力者への挑戦行為を引き起こすのである。ゆえに，政治的不安定化は権力者と権力外主体の利得の差と権力外主体の勢力規模に規定される。本稿では都市と農村の亀裂を例としてこの勝利連合の変更と制度からの逸脱について理論化を試みる。さらに，理論を検証するため，フィリピンの事例を取りあげる。フィリピンでは，民主化後にそれまでの都市セクター偏重が転換され，都市は政権に対して恒常的に不支持の傾向を示してきた。そうしたなか，2001年には，都市エリートを中心として，大統領を排除しようとする憲法制度外行動が発生し，権力者が交代することになった。

Project Neos; a generalized study of processes for the realization of esign configurations in materials. [Final] technical documentary report no. ML-TDR-64-311. MTD project no.7-867.

Mode of access: Internet.

InAs self-assembled quantum dots grown on an InP (311)B substrate by molecular beam epitaxy

Self-assembled InAs quantum dots (QDs) have been grown by solid-source molecular beam epitaxy on a (311)B InP substrate. Transmission electron microscopy clearly shows that a high density of smaller InAs islands can be obtained by using such a high index substrate. After introducing a lattice-matched underlying In0.52Al0.24Ga0.24As layer, the InAs QDs are much more uniform in size and form two-dimensional well ordered arrays. The photoluminescence (PL) spectra also confirm that the InAs QDs grown on underlying In0.52Al0.24Ga0.24As have a better quality than those grown in the In0.52Al0.48As matrix. A simple calculation indicates that the redshift of the PL peak energy mainly results from InAs QDs on underlying In0.52Al0.24Ga0.24As of large size. (C) 2001 American Institute of Physics.

Self-organized type-II In0.55Al0.45As/Al0.50Ga0.50As quantum dots realized on GaAs(311)A

Self-organized In0.55Al0.45As/Al0.50Ga0.50As quantum dots are grown by the Stranski-Krastanow growth mode using molecular beam epitaxy on the GaAs(311)A substrate. The optical properties of type-II InAlAs/AlGaAs quantum dots have been demonstrated by the excitation power and temperature dependence of photoluminescence spectra. A simple model accounting for the size-dependent band gap of quantum dots is given to qualitatively understand the formation of type-II In0.55Al0.45As/Al0.50Ga0.50As quantum dots driven by the quantum-confinement-induced Gamma --> X transition. The results provide new insights into the band structure of InAlAs/AlGaAs quantum dots. (C) 2000 American Institute of Physics. [S0003-6951(00)00725-7].

Educación artística y desarrollo musical en niños de 6 y 7 años.

Resumen tomado de la revista