期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
Engineering Spin States of Isolated Copper Species in a Metal-Organic Framework Improves Urea Electrosynthesis 被引量:8
1
作者 yuhang gao Jingnan Wang +4 位作者 Yijun Yang Jian Wang Chuang Zhang Xi Wang Jiannian Yao 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第9期536-549,共14页
The catalytic activities are generally believed to be relevant to the electronic states of their active center, but understanding this relationship is usually difficult. Here, we design two types of catalysts for elec... The catalytic activities are generally believed to be relevant to the electronic states of their active center, but understanding this relationship is usually difficult. Here, we design two types of catalysts for electrocatalytic urea via a coordination strategy in a metal–organic frameworks: Cu^(Ⅲ)-HHTP and Cu^(Ⅱ)-HHTP. Cu^(Ⅲ)-HHTP exhibits an improved urea production rate of 7.78 mmol h^(−1)g^(−1) and an enhanced Faradaic efficiency of 23.09% at-0.6 V vs. reversible hydrogen electrode, in sharp contrast to Cu^(Ⅱ)-HHTP.Isolated CuⅢspecies with S = 0 spin ground state are demonstrated as the active center in Cu^(Ⅲ)-HHTP, different from Cu^(Ⅱ) with S = 1/2 in Cu^(Ⅱ)-HHTP. We further demonstrate that isolated Cu^(Ⅲ)with an empty dx2-y20orbital in Cu^(Ⅲ)-HHTP experiences a single-electron migration path with a lower energy barrier in the C–N coupling process, while Cu^(Ⅱ)with a single-spin state( d_(x2-y2)^(1)) in Cu^(Ⅱ)-HHTP undergoes a two-electron migration pathway. 展开更多
关键词 ELECTROCATALYSIS Urea synthesis Metal-organic framework Spin catalysis C-N coupling
下载PDF
Stability Mechanisms of Gas Bubbles Subject to Ultrasonic Field during the Rectified Diffusion in Liquids 被引量:1
2
作者 yuhang gao Xiaoze Du 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2019年第1期68-76,共9页
The spherical oscillation of a gas bubble in liquids is important to growth in liquids during rectified diffusions( e. g., the onset of the sonoluminescence and the enhancement of sonochemical reactions). The present ... The spherical oscillation of a gas bubble in liquids is important to growth in liquids during rectified diffusions( e. g., the onset of the sonoluminescence and the enhancement of sonochemical reactions). The present paper numerically shows stability maps( divided into four zones),in which gas bubbles maintain the linearly spherical oscillation without nonlinear disturbance of rectified diffusions within a large range of bubble radius. The critical pressures of spherical and diffusional oscillations are two decisive indexes determining the stability status. Specifically,the stability boundaries and influential factors( including acoustic parameters and gas concentration in liquids) were discussed and analyzed. The results show that the variations of gas concentration and acoustic parameters dramatically changed the stable status of the gas bubbles. The gas bubble maintained stable status when external parameters and gas concentration were set between the two critical values properly. The cases of high-frequency and low-frequency limits were also introduced at the end of the whole paper. 展开更多
关键词 CAVITATION GAS BUBBLE GAS concentration rectified diffusion SPHERICAL OSCILLATION
下载PDF
Evaluation Model of Emergency Evacuation Capacity of Subway Station Based on Grounded Theory 被引量:2
3
作者 Lianhua Cheng yuhang gao 《World Journal of Engineering and Technology》 2019年第2期27-37,共11页
In order to evaluate the emergency evacuation capacity of subway stations, the data collected were analyzed based on grounded theory, and an evaluation model of emergency evacuation capacity was constructed by combini... In order to evaluate the emergency evacuation capacity of subway stations, the data collected were analyzed based on grounded theory, and an evaluation model of emergency evacuation capacity was constructed by combining the analytic hierarchy process (AHP). Finally, 12 secondary indicators (categories) and 4 primary indicators (main categories) were obtained, among which the primary indicators were management factors, emergency response, construction factors and personnel factors. From the weight value calculated by analytic hierarchy process, we can see that management factors and emergency response have great influence on the emergency evacuation capacity of subway stations. Therefore, we should focus on management factors and emergency response to improve the emergency evacuation capacity of subway stations. 展开更多
关键词 EMERGENCY EVACUATION Capacity ANALYTIC HIERARCHY Process Grounded THEORY
下载PDF
PowerDetector:Malicious PowerShell Script Family Classification Based on Multi-Modal Semantic Fusion and Deep Learning 被引量:1
4
作者 Xiuzhang Yang Guojun Peng +2 位作者 Dongni Zhang yuhang gao Chenguang Li 《China Communications》 SCIE CSCD 2023年第11期202-224,共23页
Power Shell has been widely deployed in fileless malware and advanced persistent threat(APT)attacks due to its high stealthiness and live-off-theland technique.However,existing works mainly focus on deobfuscation and ... Power Shell has been widely deployed in fileless malware and advanced persistent threat(APT)attacks due to its high stealthiness and live-off-theland technique.However,existing works mainly focus on deobfuscation and malicious detection,lacking the malicious Power Shell families classification and behavior analysis.Moreover,the state-of-the-art methods fail to capture fine-grained features and semantic relationships,resulting in low robustness and accuracy.To this end,we propose Power Detector,a novel malicious Power Shell script detector based on multimodal semantic fusion and deep learning.Specifically,we design four feature extraction methods to extract key features from character,token,abstract syntax tree(AST),and semantic knowledge graph.Then,we intelligently design four embeddings(i.e.,Char2Vec,Token2Vec,AST2Vec,and Rela2Vec) and construct a multi-modal fusion algorithm to concatenate feature vectors from different views.Finally,we propose a combined model based on transformer and CNN-Bi LSTM to implement Power Shell family detection.Our experiments with five types of Power Shell attacks show that PowerDetector can accurately detect various obfuscated and stealth PowerShell scripts,with a 0.9402 precision,a 0.9358 recall,and a 0.9374 F1-score.Furthermore,through singlemodal and multi-modal comparison experiments,we demonstrate that PowerDetector’s multi-modal embedding and deep learning model can achieve better accuracy and even identify more unknown attacks. 展开更多
关键词 deep learning malicious family detection multi-modal semantic fusion POWERSHELL
下载PDF
High efficiency and high transmission asymmetric polarization converter with chiral metasurface in visible and near-infrared region
5
作者 高雨航 田宇 +6 位作者 杜庆国 王原丽 付琴 卞强 李政颖 冯帅 任芳芳 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第7期368-374,共7页
Polarization manipulation of light is of great importance because it could promote development of wireless communications,biosensing,and polarization imaging.In order to use natural light more efficiently,it is highly... Polarization manipulation of light is of great importance because it could promote development of wireless communications,biosensing,and polarization imaging.In order to use natural light more efficiently,it is highly demanded to design and fabricate high performance asymmetric polarization converters which could covert the natural light to one particular linearly polarized light with high efficiency.Traditionally,polarizers could be achieved by controllers with crystals and polymers exhibiting birefringence.However,the polarizers are bulky in size and the theoretical conversion efficiency of the polarizers is limited to 0.5 with unpolarized light incidence.In this paper,we propose a polarization converter which could preserve high transmission for one linearly polarized light and convert the orthogonal linearly polarized light to its cross-polarized with high transmittance based on a multi-layer chiral metasurface.Theoretical results show that normally incident y-polarized light preserves high transmittance for the wavelength range from 685 nm to 800 nm while the orthogonal normally incident x-polarized light is efficiently converted to the y-polarized light with high transmittance from 725 nm to 748 nm.Accordingly,for unpolarized light incidence,transmittance larger than 0.5 has been successfully achieved in a broadband wavelength range from 712 nm to 773 nm with a maximum transmittance of 0.58 at 732 nm. 展开更多
关键词 asymmetric polarization converter visible and near-infrared light chiral metasurface Fabry-Perot like resonance
下载PDF
Femtosecond laser-induced graphene for temperature and ultrasensitive flexible strain sensing
6
作者 Mingle Guan Zheng Zhang +3 位作者 Weihua Zhu yuhang gao Sumei Wang Xin Li 《Frontiers of Materials Science》 SCIE 2024年第3期35-44,共10页
Flexible sensors with high sensitivity and stability are essential components of electronic skin,applicable to detecting human movement,monitoring physiological health,preventing diseases,and other domains.In this stu... Flexible sensors with high sensitivity and stability are essential components of electronic skin,applicable to detecting human movement,monitoring physiological health,preventing diseases,and other domains.In this study,we utilized a straightforward and efficient femtosecond laser direct writing technique using phenolic resin(PR)as a carbon precursor to produce high-quality laser-induced graphene(LiG)characterized by high crystallinity and low defect density.The fabricated LIG underwent comprehensive characterization using SEM,Raman spectroscopy,XPS,and XRD.Subsequently,we developed strain sensors with a hexagonal honeycomb pattern and temperature sensors with a line pattern based on PR-derived LIG.The strain sensor exhibited an outstanding measurement factor of 4.16×104 with a rapid response time of 32 ms,which is applied to detect various movements like finger movements and human pulse.Meanwhile,the temperature sensor demonstrated a sensitivity of 1.49%/°C with a linear response range of 20-5o C.The PR-derived LIG shows promising potential for applications in human physiological health monitoring and other advanced wearable technologies. 展开更多
关键词 femtosecond laser laser-induced graphene flexible sensor high sensitivity
原文传递
Organic Light-Emitting Diodes Based on an Iron(III) Complex with Doublet Emission
7
作者 Zhiyuan Cui Junshuai Ding +1 位作者 yuhang gao Feng Li 《CCS Chemistry》 CAS 2022年第9期2953-2958,共6页
Because iron is the richest transition-metal element in the earth’s crust,if iron complexes could be used as the emitters in organic light-emitting diodes(OLEDs),the cost of OLEDs would be reduced dramatically.Lumine... Because iron is the richest transition-metal element in the earth’s crust,if iron complexes could be used as the emitters in organic light-emitting diodes(OLEDs),the cost of OLEDs would be reduced dramatically.Luminescent iron(III)complexes with low-spin d5 electronic structure theoretically possess spin-allowed doublet metal-to-ligand charge transfer(^(2)MLCT)emission,but little attention has been paid to their application in OLEDs. 展开更多
关键词 doublet emission luminescent iron complex organic light-emitting diodes open-shell molecule metal-to-ligand charge transfer internal quantum efficiency
原文传递
Amorphous high-entropy phosphoxides for efficient overall alkaline water/seawater splitting
8
作者 Han-Ming Zhang Lihao Zuo +4 位作者 yuhang gao Junxia Guo Caizhen Zhu Jian Xu Jinfeng Sun 《Journal of Materials Science & Technology》 SCIE EI CAS 2024年第6期1-10,共10页
Designing and synthesizing cost-effective bifunctional catalysts for overall alkaline water/seawater splitting is still a huge challenge for hydrogen production.Herein,Co/Ni/Fe/Mn based-amorphous high-entropy phosphox... Designing and synthesizing cost-effective bifunctional catalysts for overall alkaline water/seawater splitting is still a huge challenge for hydrogen production.Herein,Co/Ni/Fe/Mn based-amorphous high-entropy phosphoxide self-standing electrode(CNFMPO)is synthesized by the facile and fast electrodeposition method.CNFMPO exhibits excellent bifunctional electrocatalytic performances on alkaline water/seawater electrolysis.The hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)overpotentials of CNFMPO in alkaline water/seawater are as low as 43/73 and 252/282 mV to reach a current density of 10 mA cm^(-2),respectively.Additionally,two-electrode electrolyzers with CNFMPO||CNFMPO successfully achieve the current density of 10 mA cm^(-2) at low voltages of 1.54 and 1.56 V for overall alkaline water/seawater splitting,respectively.CNFMPO exhibits satisfactory long-term stability on overall alkaline water/seawater splitting for the surface reconstruction into active metal hydroxide/(oxy)hydroxide,phosphite,and phosphate.Moreover,no hypochlorite is detected during seawater electrolysis for the beneficial chlorite oxidation inhibition of the reconstructed phosphite and phosphate.The excellent catalytic performances of CNFMPO are due to the unique amorphous structure,multi-component synergistic effect,beneficial electronic structure modulation,and surface reconstruction during the catalytic reaction process.Therefore,CNFMPO has shown potential promotion to the development of the water/seawater splitting industry as a promising substituent for noble-metal electrocatalysts.This work provides new insights into the design of efficient bifunctional catalysts for overall water/seawater splitting. 展开更多
关键词 Amorphous high-entropy phosphoxides Water/seawater splitting Synergistic effect Surface reconstruction Electronic structure modulation Inhibition of chloride oxidation reaction
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部