Asymmetric transfer hydrogenation in water with a supported Noyori-Ikariya catalyst

[reaction: see text] The poly(ethylene glycol)-supported ruthenium precatalyst shown above is highly effective for asymmetric transfer hydrogenation of unfunctionalized aromatic ketones by HCOONa in neat water, affording fast rates, good to excellent enantioselectivities, and outstanding reusability.     

The compatibility and morphology of chitosan-poly (ethylene oxide) blends

Thermal behavior and morphology of blends prepared by solution casting of mixtures of chitosan and poly(ethylene oxide) were studied by means of differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The preliminary results indicate that both melting point and crystallinity depend on the composition of the blends, and that they exhibit minimum values when the blend contains 50% chitosan. From the prediction of melting point depression analysis, the compatibility of the blends shows a transition at this specific composition. This conclusion was further confirmed by observation of the morphology.     

The partial inverse minimum spanning tree problem when weight increase is forbidden

In a partial inverse optimization problem there is an underlying optimization problem with a partially given solution. The objective is to find a minimal perturbation of some of the problem’s parameter values, in such a way that the partial solution becomes a part of the optimal solution.     

2维Zakharov方程组爆破解的L2集中率

讨论了2维Zakharov方程组的Caucgy问题的爆破解.对径向对称爆破解,证明了原点0是爆破点,并建立了当t→T(爆破时间)时,集中率的下界.     

Fragilolides A-Q,norditerpenoid and briarane diterpenoids from the gorgonian coral Junceella fragilis

Chemical investigation of the gorgonian coral Junceella fragilis resulted in the isolation of a new norditerpenoid fragilolide A (1), sixteen new briarane diterpenoids fragilolides B-Q (2–17), together with frajunolides H and N, and three known norcembranoids scabrolide D, sinuleptolide and 5-epi-sinuleptolide. The structures of new compounds were determined on the basis of extensive spectroscopic analysis, including the experimental and calculated ECD data and single-crystal X-ray diffraction for the configurational assignments. The structure of fragilolide A featured an unprecedented 4,13- and 7,11-fused tetracyclic norcembranoid, while the biogenetic relationships of the briarane analogues were postulated. Frajunolide H exerted significant inhibition against a panel of tumor cell lines, and six briarane diterpenoids (3, 6, 8, 12, 16, and frajunolide N) exhibited the inhibitory effects against the HBeAg express of hepatitis B virus in HepAD38 cells. In addition, sinuleptolide and 5-epi-sinuleptolide exerted the effects to inhibit NO production in RAW264.7 macrophage cells, in addition to the activation of ARE and the inhibition of NF-κB expression.     

Effects of copper and oxygen vacancies on the ferromagnetism of Mn- and Co-doped Cu2O

The ferromagnetic properties of Mn- and Co-doped Cu₂O with copper and oxygen vacancies (V_Cu and V_O) are studied by first-principles calculations. The results indicate that Mn-doped Cu₂O has an antiferromagnetic state in the near configuration, while it has a ferromagnetic state for the far configuration. On the contrary, Co-doped Cu₂O possess a ferromagnetic state regardless of the distance between the two Co atoms. The observed ferromagnetism can be attributed to the 90° ferromagnetic super-exchange mechanism. The presence of V_O can enhance the ferromagnetism, whereas V_Cudepresses it.     

只需一个解调器的偏分复用差分相移键控系统实验实现

偏分复用技术是提高系统传输速率的有效方法之一.搭建了被称为双偏振态差分相移键控(Dual-Pol.DPSK)码的新型偏分复用实验系统,它与具有相同的比特波特比的差分正交相移键控(DQPSK)调制方式相比,接收机要简单很多.与传统的偏振分解复用(POLMUX)技术相比,它无需偏振控制或偏振跟踪,只需一个解调器和一个平衡探...     

Dynamical quantum Fisher information in the Ising model

In terms of quantum Fisher information, we discuss the dynamics of quantity ${\chi }^2$ of the Ising model. The inequality ${\chi }^2<1$ detects the class of entangled states which are useful for sub-shot-noise sensitivity. All the exact dynamics of the expectations of collective spin operators are derived. The minimum ${\chi }^2$ in the plane perpendicular to the mean spin direction is analytically given. We find that ${\chi }^2$ does not depend on the system size $N$ when $N\ge 4$. Except for the periodic points, the evolution states are always entangled and useful for the sub-shot-noise phase estimation.