Synthesis and Stability of Lanthanum Superhydrides

Recent theoretical calculations predict that megabar pressure stabilizes very hydrogen‐rich simple compounds having new clathrate‐like structures and remarkable electronic properties including room‐temperature superconductivity. X‐ray diffraction and optical studies demonstrate that superhydrides of lanthanum can be synthesized with La atoms in an fcc lattice at 170 GPa upon heating to about 1000 K. The results match the predicted cubic metallic phase of LaH₁₀ having cages of thirty‐two hydrogen atoms surrounding each La atom. Upon decompression, the fcc‐based structure undergoes a rhombohedral distortion of the La sublattice. The superhydride phases consist of an atomic hydrogen sublattice with H?H distances of about 1.1 Å, which are close to predictions for solid atomic metallic hydrogen at these pressures. With stability below 200 GPa, the superhydride is thus the closest analogue to solid atomic metallic hydrogen yet to be synthesized and characterized.     

Synthesis of a novel fused thiirene sulfoxide with endoperoxide and its diels-alder adduct

Photooxidation of thiiranoradialene sulfoxide afforded a new thiirene sulfoxide fused with an endoperoxide ring, which gave the [2+4]cycloadduct with furan.     

Integrable super extensions of $$K(-2,-2)$$ equation

Theoretical and Mathematical Physics - Two coupled systems involving both bosonic and fermionic fields are proposed as super generalizations of the $$K(-2,-2)$$ equation...     

A combined experimental and theoretical investigation of donor and acceptor interface in efficient aqueous-processed polymer/nanocrystal hybrid solar cells

As a route to improving the energy conversion of organic-inorganic hybrid-solar cells, we have tested the performance of poly (phenylene vinylene) (PPV), poly(2,5-thienylene vinylene) (PWTV) polymers and CdTe nanocrystal devices produced via aqueous-processing. It is found that small differences in the conformation of the sensitizer lead to dramatic effects on the solar cell efficiency. Using a combination of UV-Vis absorption spectroscopy and first-principles non-adiabatic molecular dynamics (NAMD) based on time-dependent density-functional theory (TDDFT), PPV is found to have a longer electron injection and recombination time despite seeming to have a better energy alignment with the substrate, which leads to a higher devices performance than PWTV. The present results shed new light on the understanding of organic-inorganic hybrid-solar cells and will trigger further experimental and theoretical investigations.     

Perturbation analysis for the symplectic QR factorization

In this paper, the perturbation analysis for the symplectic QR factorization is considered. Some first-order and rigorous normwise perturbation bounds with normwise or componentwise perturbations in the given matrix are presented.     

A note on the perturbation analysis for the generalized Cholesky factorization

In this note, we consider the perturbation analysis for the generalized Cholesky factorization further. The conditions for the main theorems of the paper [W.-G. Wang, J.-X. Zhao, Perturbation analysis for the generalized Cholesky factorization, Appl. Math. Comput. 147 (2004) 601-606] are weakened by using an alternative method. Moreover, some new perturbation bounds are also derived.     

光电驱动的糖化学反应

糖类是自然界中最丰富的有机化合物,在医药、材料、能源和环境等领域发挥着重要作用。糖类化合物的分子极性大、结构复杂且存在微观不均一性,分离纯化难度极大,其合成问题已成为制约糖科学发展的瓶颈,发展高效的糖类化合物合成新方法是糖化学研究的核心内容。利用光子/电子能量驱动的反应通常能在温和的条件下发生,符合绿色化学理念和可持续发展要求,是当代有机合成化学中的研究热点之一。近些年,随着光电合成技术的进步,光/电驱动的糖化学反应也得到了快速发展。本综述从反应类型、反应机理以及研究现状方面较为系统地总结了光/电驱动的糖化学反应的研究进展,并在此基础上概括了光电驱动的糖化学反应目前面临的挑战及新的机遇。