Phosphorus gettering of precipitated Cu in single crystalline silicon based on rapid thermal process

In this paper, we have investigated the effect of phosphorus diffusion gettering on the precipitated Cu in silicon via rapid thermal process (RTP). It is found that, for dot-like or star-like precipitates, the RTP-based phosphorus diffusion technique is efficient for gettering out the precipitated Cu. A two-step RTP gettering process is much more effective than a single-step RTP process. Furthermore, the choice of oxygen ambient can enhance the Cu gettering efficiency due to the involvement of considerable self-interstitial silicon atoms. The minority carrier lifetime of the sample subjected to RTP-based phosphorus gettering has also been verified to be significantly enhanced. These results are of interest for the gettering engineering of high-efficiency silicon solar cells.     

Study on Combined Method Based on 3-D ESPI

The finite element method (FEM),whether the calculation is accurate or not,depends closely on object boundary condition.If the three dimensional displacement of the object obtained in experiment is regarded as its boundary condition,a new method combining the results of experiment and calculation,called combined method (CM),is formed.The combined method possess advantages of experiment and calculation.It can correct calculation and improve the accuracy of FEM.Accordingly it has more practicability.In this paper,the three dimensional displacement fields of a typical beam loaded at three points are tested by using 3-D electric speckle pattern interferometry (ESPI).Using the experimental results as boundary condition the whole three-dimensional displacement fields can be calculated by FEM.The beam′s three-dimensional displacement fields obtained by FEM agree very well with those obtained by experiment.This proves that the combined method is effective and practicable.     

具有不同耦合强度且带有时滞的振子网络上的同步

本文研究了具有不同耦合强度且带有时滞的振子网络上的同步问题．我们给出了该网络同步状态的稳定性准则，证实了其同步状态的稳定性与网络的拓扑性无关．最后，通过数值模拟验证了我们的理论结果．     

Graphitic‐Carbon Layers on Oxides: Toward Stable Heterogeneous Catalysts for Biomass Conversion Reactions

Conversion of biomass‐derived molecules involves catalytic reactions under harsh conditions in the liquid phase (e.g., temperatures of 250 °C and possibly under either acidic or basic conditions). Conventional oxide‐supported catalysts undergo pore structure collapse and surface area reduction leading to deactivation under these conditions. Here we demonstrate an approach to deposit graphitic carbon to protect the oxide surface. The heterogeneous catalysts supported on the graphitic carbon/oxide composite exhibit excellent stability (even under acidic conditions) for biomass conversion reactions.     

Chain‐Growth Click Polymerization of AB2 Monomers for the Formation of Hyperbranched Polymers with Low Polydispersities in a One‐Pot Process

Hyperbranched polymers are important soft nanomaterials but robust synthetic methods with which the polymer structures can be easily controlled have rarely been reported. For the first time, we present a one‐pot one‐batch synthesis of polytriazole‐based hyperbranched polymers with both low polydispersity and a high degree of branching (DB) using a copper‐catalyzed azide–alkyne cycloaddition (CuAAC) polymerization. The use of a trifunctional AB₂ monomer that contains one alkyne and two azide groups ensures that all Cu catalysts are bound to polytriazole polymers at low monomer conversion. Subsequent CuAAC polymerization displayed the features of a “living” chain‐growth mechanism with a linear increase in molecular weight with conversion and clean chain extension for repeated monomer additions. Furthermore, the triazole group in a linear (L) monomer unit complexed Cu^I, which catalyzed a faster reaction of the second azide group to quickly convert the L unit into a dendritic unit, producing hyperbranched polymers with DB=0.83.     

Regio‐ and Enantioselective Aza‐Diels–Alder Reactions of 3‐Vinylindoles: A Concise Synthesis of the Antimalarial Spiroindolone NITD609

An asymmetric aza‐Diels–Alder reaction of 3‐vinylindoles with isatin‐derived ketimines has been developed. A series of spiroindolone derivatives were thus obtained in good to excellent yields with excellent enantioselectivity (up to 96 % yield and 99 % ee). Furthermore, the antimalarial compound NITD609 could be obtained in three steps with an overall yield of 40.6 %. Control experiments and operando IR experiments imply a concerted reaction pathway. The regioselectivity and exo selectivity result from π–π interactions between the two indoline rings of the two reactants.