Quantum-trajectory analysis for charge transfer in solid materials induced by strong laser fields

We investigate the dependence of charge transfer on the intensity of driving laser field when SiO2 crystal is irradiated by an 800 nm laser. It is surprising that the direction of charge transfer undergoes a sudden reversal when the driving laser intensity exceeds critical values with different carrier envelope phases. By applying quantum-trajectory analysis, we find that the Bloch oscillation plays an important role in charge transfer in solid. Also, we study the interaction of strong laser with gallium nitride (GaN) that is widely used in optoelectronics. A pump-probe scheme is applied to control the quantum trajectories of the electrons in the conduction band. The signal of charge transfer is controlled successfully by means of theoretically proposed approach

Quantitative Supramolecular Heterodimerization for Efficient Energy Transfer.

The challenge of quantitatively forming self-assembled heterodimers without other equilibrium by-products is overcome through self-sorting favored by the introduction of designed shape-complementary moieties. Such a supramolecular strategy based on cucurbit[8]uril-directed dimerization is further applied to generate hetero-chromophore dimers quantitatively, leading to efficient energy transfer (>85 %) upon photoexcitation.This work was supported by Leverhulme Trust (“Natural material innovation for sustainable living”, G.W., O.A.S.), ERC-2016 Consolidator Grant (CAM-RIG, 726470, G.W., O.A.S.), EPSRC Programme Grant (NOtCH, EP/L027151/1, Z.H., O.A.S.), and Marie Skłodowska-Curie Fellowship (H2020-MSCA-IF-2018, 845640, Z.H.)

Oligopeptide-CB[8] complexation with switchable binding pathways.

Host-guest complexes exhibiting a 1 : 1 binding stoichiometry need not consist of a single host and guest. A series of oligopeptides, which were previously reported to have abnormally high binding enthalpies were investigated to deduce whether they exist as a 2 : 2 quaternary or a 1 : 1 binary complex with cucurbit[8]uril (CB[8]). Through a systematic study of the sequence-specific binding pathways of peptide-CB[8] association, a phenylalanine-leucine dipeptide was found to be capable of switching from a 1 : 1 stoichiometric complex to a 2 : 1 complex. By studying the differences in size-based diffusion properties of these two binding modes, the presence of a 1 : 1 pairwise inclusion complex was verified for the regime where CB[8] is in excess. Findings in this study can be utilised to 'customise' the precise CB[8]-oligopeptide self-assembly pathway, acting as a useful toolbox in the design of supramolecular systems.The Leverhulme Trust Marie Curie FP7 ERC EPSR

Time- or Space-Dependent Coefficient Recovery in Parabolic Partial Differential Equation for Sensor Array in the Biological Computing

This study presents numerical schemes for solving a parabolic partial differential equation with a time- or space-dependent coefficient subject to an extra measurement. Through the extra measurement, the inverse problem is transformed into an equivalent nonlinear equation which is much simpler to handle. By the variational iteration method, we obtain the exact solution and the unknown coefficients. The results of numerical experiments and stable experiments imply that the variational iteration method is very suitable to solve these inverse problems

Nonnegative polynomial optimization over unit spheres and convex programming relaxations

We consider approximation algorithms for nonnegative polynomial optimization over unit spheres. Such optimization models have wide applications, e.g., in signal and image processing, high order statistics, and computer vision. Since polynomial functions are nonconvex, the problems under consideration are all NP-hard. In this paper, based on convex polynomial optimization relaxations, we propose polynomial-time approximation algorithms with new approximation bounds. Numerical results are reported to show the effectiveness of the proposed approximation algorithms

Cucurbit[8]uril-mediated pseudo[2,3]rotaxanes.

Pseudo[2,3]rotaxanes have been successfully fabricated by the complexation of cucurbit[8]uril (CB[8]) macrocycles with extended viologen derivatives. Two design rules enable the incorporation of a third CB[8] onto a recently reported pseudo[2,2]rotaxane. Incorporation of a third macrocycle confines the dimeric stacking of chromophores into specific alignment, leading to effective electron-delocalisation along their long molecular axis.- Leverhulme Trust (project: “Natural material innovation for sustainable living”), - EPSRC Programme Grant (NOtCH, EP/L027151/1), - ERC-2016 Consolidator Grant (CAM-RIG, 726470,), - EPSRC (EP/R013012/1, EP/N020669/1), - BBSRC (BB/N007700/1), - ERC Starting Grant (BioNet,757850

Surface-Bound Cucurbit[8]uril Catenanes on Magnetic Nanoparticles Exhibiting Molecular Recognition.

We demonstrate the preparation of surface-bound cucurbit[8]uril (CB[8]) catenanes on silica nanoparticles (NPs), where CB[8] was employed as a tethered supramolecular "handcuff" to selectively capture target guest molecules. In this catenane, CB[8] was threaded onto a methyl viologen (MV(2+) ) axle and immobilized onto silica NPs. The formation of CB[8] catenanes on NPs were confirmed by UV/Vis titration experiments and lithographic characterization, demonstrating a high density of CB[8] on the silica NPs surface, 0.56 nm(-2) . This CB[8] catenane system exhibits specific molecular recognition towards certain aromatic molecules such as perylene bis(diimide), naphthol and aromatic amino acids, and thus it can act as a nanoscale molecular receptor for target guests. Furthermore, we also demonstrate its use as an efficient and recyclable nano-platform for peptide separation. By embedding magnetic NPs inside silica NPs, separation could be achieved by simply applying an external magnetic field. Moreover, the peptides captured by the catenanes could be released by reversible single-electron reduction of MV(2+) . The entire process demonstrated high recoverability.X. Ren thanks the CSC Cambridge Scholarship for financial support and Dr. Ziyi Yu for template preparation. Y. Wu is financially supported by the EP/L504920/1, J. Liu by the Marie Curie FP7 SASSYPOL ITN (607602) programme, and G. Wu by the Leverhulme Trust.This is the author accepted manuscript. The final version is available from Wiley at http://dx.doi.org/10.1002/asia.201600875