University of Electronic Science and Technology of China

About: University of Electronic Science and Technology of China is a education organization based out in Chengdu, China. It is known for research contribution in the topics: Antenna (radio) & Dielectric. The organization has 50594 authors who have published 58502 publications receiving 711188 citations. The organization is also known as: UESTC.

Recent progress in van der Waals heterojunctions

Abstract: Following the development of many novel two-dimensional (2D) materials, investigations of van der Waals heterojunctions (vdWHs) have attracted significant attention due to their excellent properties such as smooth heterointerface, highly gate-tunable bandgap, and ultrafast carrier transport. Benefits from the atom-scale thickness, physical and chemical properties and ease of manipulation of the heterojunctions formulated by weak vdW forces were demonstrated to indicate their outstanding potential in electronic and optoelectronic applications, including photodetection and energy harvesting, and the possibility of integrating them with the existing semiconductor technology for the next-generation electronic and sensing devices. In this review, we summarized the recent developments of vdWHs and emphasized their applications. Basically, we introduced the physical properties and some newly discovered phenomena in vdWHs. Then, we emphatically presented four classical vdWHs and some novel heterostructures formed by vdW forces. Based on their unique physical properties and structures, we highlighted the applications of vdWHs including in photodiodes, phototransistors, tunneling devices, and memory devices. Finally, we provided a conclusion on the recent advances in vdWHs and outlined our perspectives. We aim for this review to serve as a solid foundation in this field and to pave the way for future research on vdW-based materials and their heterostructures.

Contrast Agents for Photoacoustic and Thermoacoustic Imaging: A Review

Abstract: Photoacoustic imaging (PAI) and thermoacoustic imaging (TAI) are two emerging biomedical imaging techniques that both utilize ultrasonic signals as an information carrier. Unique advantages of PAI and TAI are their abilities to provide high resolution functional information such as hemoglobin and blood oxygenation and tissue dielectric properties relevant to physiology and pathology. These two methods, however, may have a limited detection depth and lack of endogenous contrast. An exogenous contrast agent is often needed to effectively resolve these problems. Such agents are able to greatly enhance the imaging contrast and potentially break through the imaging depth limit. Furthermore, a receptor-targeted contrast agent could trace the molecular and cellular biological processes in tissues. Thus, photoacoustic and thermoacoustic molecular imaging can be outstanding tools for early diagnosis, precise lesion localization, and molecular typing of various diseases. The agents also could be used for therapy in conjugation with drugs or in photothermal therapy, where it functions as an enhancer for the integration of diagnosis and therapy. In this article, we present a detailed review about various exogenous contrast agents for photoacoustic and thermoacoustic molecular imaging. In addition, challenges and future directions of photoacoustic and thermoacoustic molecular imaging in the field of translational medicine are also discussed.

Scalable and DiI-compatible optical clearance of the mammalian brain

Abstract: Efficient optical clearance is fundamental for whole brain imaging. In particular, clearance of the brain without membrane damage is required for the imaging of lipophilic tracer-labeled neural tracts. Relying on an ascending gradient of fructose solutions, SeeDB can achieve sufficient transparency of the mouse brain while ensuring that the plasma membrane remains intact. However, it is challenging to extend this method to larger mammalian brains due to the extremely high viscosity of the saturated fructose solution. Here we report a SeeDB-derived optical clearing method, termed FRUIT, which utilizes a cocktail of fructose and urea. As demonstrated in the adult mouse brain, combination of these two highly water-soluble clearing agents exerts a synergistic effect on clearance. More importantly, the final FRUIT solution has low viscosity so as to produce transparency of the whole adult rabbit brain via arterial perfusion, which is impossible to achieve with a saturated fructose solution. In addition to good compatibility with enhanced yellow fluorescent protein, the cocktail also preserves the fluorescence of the lipophilic tracer DiI. This work provides a volume-independent optical clearing method which retains the advantages of SeeDB, particularly compatibility with lipophilic tracers.

Direction of Arrival Estimation in Time Modulated Linear Arrays With Unidirectional Phase Center Motion

Abstract: A novel approach for estimating the direction of arrivals (DOAs) in time modulated linear arrays (TMLAs) with unidirectional phase center motion (UPCM) scheme is proposed in this paper. Based on the fact that the main beams of the patterns at different sidebands can be directed at different directions, the corresponding received signals can be used to compose a received data space. Thus, the spatial locations of the far-field sources can be estimated by using multiple signal classification (MUSIC) algorithm. Simulation results of the DOA estimation in an 8-element TMLA with the UPCM scheme validate the proposed approach, where the performance such as the accuracy and resolution of the DOA estimation is obtained through Monte-Carlo simulations. As compared to the DOA estimation based on conventional uniform linear arrays (ULAs), a much better resolution performance is obtained.