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| 1 | Single atom accelerates ammonia photosynthesis显示文摘Atomically dispersed metal has gained much attention because of the new opportunities they offer in catalysis. However, it is still crucial to understand the mechanism of single-atom catalysis at molecular level for expanding them to other more difficult catalytic reactions, such as ammonia synthesis from nitrogen. In fact, developing ammonia synthesis under ambient conditions to overcome the high energy consumption in well-established Haber-Bosch process has fascinated scientists for many years.Herein, we demonstrate that single Cu atom yields facile valence-electron isolation from the conjugated π electron cloud of p-CN. Electron spin resonance measurements reveal that these isolated valence electrons can be easily excited to generate free electrons under photo-illumination, thus inducing high efficient photo-induced ammonia synthesis under ambient conditions.The NH_3 producing rate of copper modified carbon nitride(Cu-CN) reached 186 μmol g^(-1) h^(-1) under visible light irradiation with the quantum efficiency achieved 1.01% at 420 nm monochromatic light. This finding surely offers a model to open up a new vista for the ammonia synthesis at gentle conditions. The introduction of single atom to isolate the valence electron also represents a new paradigm for many other photocatalytic reactions, since the most photoinduced processes have been successfully exploited sharing the same origin. | Pengcheng Huang Wei Liu Zhihai He Chong Xiao Tao Yao Youming Zou Chengming Wang Zeming Qi Wei Tong Bicai Pan Shiqiang Wei Yi Xie | 2018 | Science China Chemistry2018，61，9： | 8 |
| 2 | An Improved Image Enhancement Algorithm显示文摘To solve the problems of noise,detail loss and poor contrast in the successive mean quantization transform(SMQT),a new SMQT algorithm based on Otsu algorithm is proposed.In this algorithm,we integrate the optimal threshold selected by the Otsu algorithm into the SMQT algorithm,then obtain the successive mean quantization of the binary tree.By this algorithm,an enhanced image is output with a higher quality.From both subjective visual effect and objective quality evaluation,the experimental results show that the improved algorithm reduces noise,improves contrast and makes the image details more clear. | MA Jing ZOU Chengming JIN Xiaolong | 2017 | Wuhan University Journal of Natural Sciences2017，22，1： | 3 |
| 3 | 3D placement of unmanned aerial vehicles and partially overlapped channel assignment for throughput maximization显示文摘This paper investigates a wireless system with multi-Unmanned Aerial Vehicles(UAVs)for improving the overall throughput.In contrast to previous studies that optimize the locations of UAVs and channel assignment separately,this paper considers the two issues jointly by exploiting Partially Overlapped Channels(POCs).The optimization problem of maximizing network throughput is formulated as a non-convex and non-linear problem.In order to find a practical solution,the problem is decomposed into two subproblems,which are iteratively optimized.First,the optimal locations of UAVs are determined under a fixed channel assignment scheme by solving the mixed-integer second-order cone problem.Second,an efficient POC allocation scheme is determined via the proposed channel assignment algorithm.Simulation results show that the proposed approach not only significantly improves system throughput and service reliability compared with the cases in which only orthogonal channels and stationary UAVs are considered,but also achieves similar performance using the exhaustive search algorithm with lower time complexity. | Chengming Zou Xiaoxiao Li Xing Liu Mengya Zhang | 2021 | Digital Communications and Networks2021，7，2： | 1 |
| 4 | Edge localized modes suppression via edge E × B velocity shear induced by RF sheath of ion cyclotron resonance heating in EAST显示文摘The control of large edge localized modes(ELMs) is a critical issue for the successful operation of future burning plasma devices,such as the international thermonuclear experimental reactor(ITER) and China fusion engineering test reactor(CFETR). In this paper, we present a new active and effective means of ELM suppression using ion cyclotron resonant heating(ICRH) on the experimental advanced superconducting tokamak(EAST). We obtained the key role of the external E × B velocity shear near the pedestal top and the scrape-off-layer(SOL) induced by the RF sheath potential of ICRH in ELM suppression. The experimental results showed a positive correlation between the RF sheath and the E × B shear rate in SOL. BOUT++ simulations indicate that increased E × B velocity shear rates in the pedestal and SOL regions promote ELM suppression;thereby, supporting the experimental observations on EAST. These findings suggest a new simple approach to access the ELM suppressed regimes in plasma with low torque input as ITER baseline discharges. | XinJun Zhang Chu Zhou XiaoLan Zou TianYang Xia YanLong Li ChengMing Qin XianZu Gong Qing Zang MingHui Li Tao Zhang ShouXin Wang HaiQing Liu Guillaume Urbanczyk Adi Liu YanMing Duan YanPing Zhao JinPing Qian Robert Isaac Pinsker MinYou Ye BaoNian Wan | 2022 | Science China(Physics,Mechanics & Astronomy)2022，65，3： | 0 |
| 5 | Beyond Video Quality:Evaluation of Spatial Presence in 360-Degree Videos显示文摘With the rapid development of immersive multimedia technologies,360-degree video services have quickly gained popularity and how to ensure sufficient spatial presence of end users when viewing 360-degree videos becomes a new challenge.In this regard,accurately acquiring users’sense of spatial presence is of fundamental importance for video service providers to improve their service quality.Unfortunately,there is no efficient evaluation model so far for measuring the sense of spatial presence for 360-degree videos.In this paper,we first design an assessment framework to clarify the influencing factors of spatial presence.Related parameters of 360-degree videos and headmounted display devices are both considered in this framework.Well-designed subjective experiments are then conducted to investigate the impact of various influencing factors on the sense of presence.Based on the subjective ratings,we propose a spatial presence assessment model that can be easily deployed in 360-degree video applications.To the best of our knowledge,this is the first attempt in literature to establish a quantitative spatial presence assessment model by using technical parameters that are easily extracted.Experimental results demonstrate that the proposed model can reliably predict the sense of spatial presence. | ZOU Wenjie GU Chengming FAN Jiawei HUANG Cheng BAI Yaxian | 2023 | ZTE Communications2023，21，4： | 0 |
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