Interactions between clusters of self-interstitial atoms via a conservative climb in BCC–Fe

We conduct kinetic Monte Carlo simulations for the conservative climb motion of a cluster of self-interstitial atoms (SIAs) towards another SIA cluster in BCC–Fe; the conservative climb velocity is inversely proportional to the fourth power of the distance between them, as per the prediction based on Einstein’s equation. The size of the climbing cluster significantly affects its conservative climb velocity, while the size of the cluster that originates the stress field does not. The activation energy for the conservative climb is considerably greater than that derived in previous studies and strongly dependent on the climbing cluster size. The results presented in this study are the atomistic evaluation of the behaviour of SIA clusters through three-dimensional motion, which cannot be achieved using molecular dynamics techniques alone.     

THEORETICAL AND EXPERIMENTAL STUDIES OF STRESS DISTRIBUTION IN WEDGE-SHAPED GRANULAR HEAPS

The present work explains the statics of self-weight transmission restricted to a long prismatic heap inclined at an angle of repose and symmetrically formed on a rigid base. The closure of polarized principal axes with the mobilized state of stress along the slope surface is employed by imposing the orientation of principal stresses on the equilibrium equations. Comparisons were made with calculations based on the finite element method using an elastic model. Moreover, experiments on sand heaps deposited on a rectangular rigid base were conducted to validate the theoretical study. The measured pressure profile generally agreed well with theoretical results.     

Design of efficient thermally activated delayed fluorescence materials for pure blue organic light emitting diodes

Efficient thermally activated delayed fluorescence (TADF) has been characterized for a carbazole/sulfone derivative in both solutions and doped films. A pure blue organic light emitting diode (OLED) based on this compound demonstrates a very high external quantum efficiency (EQE) of nearly 10% at low current density. Because TADF only occurs in a bipolar system where donor and acceptor centered (3)ππ* states are close to or higher than the triplet intramolecular charge transfer ((3)CT) state, control of the π-conjugation length of both donor and acceptor is considered to be as important as breaking the π-conjugation between them in blue TADF material design.     

Total Synthesis of Hydroxy-α- and Hydroxy-β-sanshool Using Suzuki-Miyaura Coupling

Here, we describe the first total synthesis of hydroxyl-α- and hydroxyl-β-sanshool, which involves Suzuki-Miyaura coupling (SMC). Hydroxy-α-sanshool (1) was synthesized by SMC of bromoalkyne 4 with boronate 3 followed by (Z)-selective reduction of the triple bond in the coupling product. Hydroxy-β-sanshool (2) was synthesized by regio- and (E)-selective conversion of 4 to iodoalkene 11 followed by SMC with 3.     

二（2,6-二甲基-4-甲氧基）苯基卡宾的产生和反应

为了考察卡宾稳定性的电子效应,合成了对位具有强推电性甲氧基的二（2, 6-二甲基-4-甲氧基）苯基重氮甲烷(1c),通过光分解而产生了二（2,6-二甲基- 4-甲氧基）苯基卡宾(2c)。分别用电子顺磁共振（EPR）光谱,紫外可见(UV/vis) 光谱及激光闪光光分解法对二（2,6-二甲基-4-甲氧基）苯基卡宾(2c)的产生和衰 减过程进行了详细的观察。由于甲氧基的强推电子作用使二苯基卡宾的稳定性大大 降低,其二次动力学衰减速度常数为130s~(-1),是对位非取代二苯基卡宾(2b) (14s~(-1))的约9倍,且室温苯溶液中的寿命为20ms,仅为2b(180ms)的1/9。且通过 产物分析对二（2,6-二甲基-4-甲氧基）苯基卡宾(2c)的反应及甲氧基的取代基效 应进行了详细探讨。     

立体拥挤二苯基卡宾分子结构的电子效应

通过对二苯基重氮甲烷的光照射产生了一系列具有对称对位取代基的三线态二(2,6-二甲苯基)卡宾.用电子顺磁共振波谱对其进行了研究.通过对不同粘度的基质(matrix)中零磁场分裂参数D和E的测定,依据电子自旋离域取代基常数σr对三线态二苯基卡宾的分子结构的取代基效应进行了分析.并通过对卡宾的热消失温度及其室温脱气苯溶液中寿命的测定,对三线态二(2,6-二甲苯基)卡宾的稳定性进行了定量考察.结果表明,对卡宾中心的自旋电子具有离域效应的取代基使三线态二(2,6-二甲苯基)卡宾采取低能稳定的直线型结构,且显示了更好的热稳定性和更长的寿命.     

Host–guest‐like thi­amine–anion complexation in thia­minium bis­(tetra­fluoro­borate)

In the title compound, 3‐[(4‐amino‐2‐methyl‐5‐pyrimidin‐1‐io)methyl]‐5‐(2‐hydroxy­ethyl)‐4‐methyl­thia­zolium(2+) bis(tetra­fluoro­borate), C₁₂H₁₈N₄OS²⁺·2BF₄^?, the divalent thia­mine cation (in the F conformation) is associated with BF₄^? anions via two characteristic bridging interactions between the thia­zolium and pyrimidinium rings, i.e. C—H?BF₄^??pyrimidinium and N—H?BF₄^??thia­zolium interactions. Thi­amine mol­ecules are linked by N—H?O hydrogen bonds to form a helical chain structure.     

Controlled release of DNA from zinc and magnesium ion-doped hydroxyapatites

Research on Chemical Intermediates - Hydroxyapatite (HA) is a biocompatible and porous material that is useful for gene delivery. In this study, various Zn- and Mg-doped HA samples were produced by...     

Spin-oriented projectile fragments: The first application tog-factor measurements

Ejectile nuclei in the fragmentation of intermediate-energy heavy-ion projectiles were found to be largely spin polarized. The observed polarization as a function of the outgoing momentum was nicely explained by a simple kinematical argument based on the participant-spectator model of projectile fragmentation. The measurements extended to cover several different targets, incident energies, exit channels, and emission angles revealed that substantial polarization shows up widely in projectile fragmentation reactions. Furthermore, this polarization exhibits an interesting behavior which may be interpreted as a manifestation of a gradual change in the deflection angle from positive to negative values as the energy increases and/or the target-Z decreases. The present polarization results also suggests various applications of spin polarized radioactive beams. As the first example of such an application, we present a recent result on theg-factor measurements on neutron-rich nuclei.