Electrospinning is a straightforward and versatile method to fabricate ultrafine fibers with unique physical and chemical properties. However, the chaotic nature of traditional electrospinning limits its applications in devices which usually need arranged or patterned micro/nanoscale fibrous structures. In order to improve the controllable deposition of electrospun fibers, near-field electrospinning (NFES) has been proposed and developed in recent years. With characteristics of position-controlled deposition, NFES significantly expands the range of fiber-fabrication uses including electronic components, energy harvesting, flexible sensors, and tissue engineering. In this paper, the basic principle and research advances of NFES have been briefly reviewed. In particular, we summarize the process parameters, polymer materials, as-spun fibrous structures, modified apparatus, and potential applications of NFES. Finally, future prospects on the development tendency and challenges of NFES are discussed.

Singlet fission (SF) is supposed to potentially improve the efficiency of solar energy conversion in organic photovoltaic systems. The multilayer multiconfigurational time-dependent Hartree (ML-MCTDH) method was employed to describe the singlet fission of the pentacene system with a three-state model. The ML-MCTDH result agrees well with the previous simulations using the Redfield theory, the hierarchical equation of motion (HEOM) and the symmetrical quasi-classical (SQC) theory. We carefully investigated the role of vibrational modes with different frequencies in singlet fission dynamics. Interestingly, we observed the important contribution of a few modes with frequency resonance to electronic transition. Such a finding can be understood by revisiting the superexchange mechanism within the framework of Fermi’s golden rule. As a numerically exact method, ML-MCTDH not only provides an accurate description of the microscopy insight of the SF dynamics but also provides benchmark results to examine the performance of other approximated dynamical methods.

Electron transfer at the donor-acceptor heterojunctions plays a critical role in the photoinduced process during the solar energy conversion in organic photovoltaic materials. We theoretically investigate the electron transfer process in the anthracene/C60 donor-acceptor complex by using quantum dynamics calculations. The electron-transfer model Hamiltonian with full dimensionality was built by quantum-chemical calculations. The quantum dynamics calculations were performed using the multiconfigurational time-dependent Hartree (MCTDH) theory and multilayer (ML) MCTDH methods. The latter approach (ML-MCTDH) allows us to conduct the comprehensive study on the quantum evolution of the full-dimensional electron-transfer model including 4 electronic states and 246 vibrational degrees of freedom. Our quantum dynamics calculations exhibit the ultrafast anthracene → C60 charge transfer process because of the strong coupling between excitonic and charge transfer states. This work demonstrates that the ML-MCTDH is a very powerful method to treat the quantum evolution of complex systems.

A highly efficient and convenient method for the synthesis of 1,2,4,5-tetrasubstituted imidazoles from readily accessible 2-azido acrylates and nitrones has been developed. This reaction proceeded under mild conditions without the assistance of any metal, acid, or base.

The symmetrical quasi-classical dynamics method based on the Meyer-Miller mapping Hamiltonian (MM-SQC) shows the great potential in the treatment of the nonadiabatic dynamics of complex systems. We performed the comprehensive benchmark calculations to evaluate the performance of the MM-SQC method in various site-exciton models with respect to the accurate results of quantum dynamics method multilayer multiconfigurational time-dependent Hartree (ML-MCTDH). The parameters of the site-exciton models are chosen to represent a few of prototypes used 2 in the description of photoinduced excitonic dynamics processes in photoharvesting systems and organic solar cells, which include the rather board situations with the fast or slow bath and different system-bath couplings. When the characteristic frequency of the bath is low, the MM-SQC method performs extremely well, and it gives almost the identical results to those of ML-MCTDH. When the fast bath is considered, the deviations exist between the MM-SQC and ML-MCTDH results if the high-frequency bath modes are improperly treated by the classical manner. When the so-called adiabatic renormalization was employed to construct the reduced Hamiltonian by freezing high-frequency modes, the MM-SQC dynamics can give the results comparable to the ML-MCTDH ones. Thus, the MM-SQC method itself provide reasonable results in all test site-exciton models, while the proper treatments of the bath modes must be employed. The possible dependence of the MM-SQC dynamics on the different initial sampling methods for the nuclear degrees of freedom is also discussed.3

We have developed a novel strategy to control the product distribution between 2,3-dihydrofurans and biaryls from the same starting materials by tuning the catalytic or stoichiometric process. By controlling the loading of the phosphine PR 3 , the Morita-Baylis-Hillman carbonates can be selectively used as a C 1 or a C 3 synthon, respectively. This inves-tigation has given new insights into tunable domino reactions and will be useful in diversity-oriented synthesis (DOS).Scheme 1. Our work concerned with the phosphine-mediated domino reactions of Morita-Baylis-Hillman carbonates.

Sequential catalysis of a [2+4] reaction between a Baylis–Hillman carbonate and a β,γ‐unsaturated α‐oxo ester for the synthesis of 2‐methyl‐2H‐pyran was developed. The use of a Morita–Baylis–Hillman carbonate as a C2 synthon is first disclosed in this reaction. This method offers a new approach to the construction of 2‐methyl‐2H‐pyrans and 2‐oxabicyclo[2.2.2]oct‐5‐ene skeletons.

Licensed-Assisted Access (LAA) using Long Term Evolution (LTE) is a promising solution to alleviate the problem of scarce spectrum resources by extending to the unlicensed band. However, co-existence mechanisms should be carefully taken into consideration to provide fair co-existence to other LAA and 802.11 based Wi-Fi networks that operate on the same unlicensed carrier. In this paper, we focus on the design of listen-before-talk (LBT) for the LAA system and provide insights into the impact of LAA clear channel assessment (CCA) threshold on the trade-off between frequency reuse and interference avoidance. Moreover, an enhanced LBT scheme is proposed by adaptively adjusting the LAA CCA threshold to exploit the benefits of frequency reuse for LAA while guaranteeing the fair co-existence with Wi-Fi at the same time. System-level simulation is performed to analyze the CCA threshold among LAA networks and evaluate the effectiveness of the proposed LBT scheme compared to that with fixed CCA threshold. It is shown that significant performance gains can be achieved for LAA by using the proposed LBT scheme under efficient protection of Wi-Fi performance.