Article
Chemistry, Analytical
Hai-Han Sun, Yee Hui Lee, Wenhao Luo, Lai Fern Ow, Mohamed Lokman Mohd Yusof, Abdulkadir C. Yucel
Summary: The proposed compact ultra-wideband dual-polarized Vivaldi antenna demonstrates excellent impedance matching, port isolation, and dual-polarized radiation performance in the frequency range of 0.4 GHz to 3.0 GHz with low dispersion characteristics. Ground-penetrating radar (GPR) measurements indicate that the antenna maintains good detection capability even for objects buried in highly conductive soil.
Article
Computer Science, Information Systems
Jia-Cheng Liang, Cheng-Nan Chiu, Tsung-Ching Lin, Chih-Hung Lee
Summary: This paper presents a novel ultrawideband antenna that exhibits high gain and circular polarization. The antenna consists of four sophisticated antipodal Vivaldi antennas and an ultrawideband feeding network. The antenna achieves circular polarization that can be easily switched between right-handed and left-handed. The experimental results demonstrate that the antenna has a wide impedance-matching bandwidth and stable gain, making it suitable for applications in the Ku, K, and Ka frequency bands.
Article
Astronomy & Astrophysics
Maryam Eshaghpanah, Farzad Mohajeri
Summary: This paper investigates the issue of improving the gain and bandwidth of microstrip antennas using log-periodic structures. Different shapes of 8-element log-periodic structure antennas are designed, simulated, and fabricated to obtain the bandwidth and maximum gain. The results show that the V-shaped antenna has the highest bandwidth, while the U-shaped antenna has the highest maximum gain.
Article
Engineering, Electrical & Electronic
Xiaoyu Liu, Yongzhong Zhu, Wenxuan Xie
Summary: This letter presents the design of a compact broadband circularly polarized (CP) array antenna using the Vivaldi element. The antenna consists of four sequentially rotated Vivaldi antenna elements bent into the aperture for miniaturization. A coupling metal patch on the top enhances impedance, circular polarization, and gain characteristics. The measured results show a 10 dB impedance bandwidth of 57.8% and a 3 dB axial ratio bandwidth of 50.7%. The antenna also has a peak gain of 5.6 dBic across the entire operating bandwidth, making it highly miniaturized compared to similar antennas.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Computer Science, Information Systems
Mian Muhammad Kamal, Shouyi Yang, Xin-cheng Ren, Ahsan Altaf, Saad Hassan Kiani, Muhammad Rizwan Anjum, Amjad Iqbal, Muhammad Asif, Sohail Imran Saeed
Summary: This paper introduces and investigates a novel single layer MIMO antenna design for efficient operation in 5G mm-wave communication, with low Envelope Correlation Coefficient (ECC), higher efficiency, and satisfactory gain.
Article
Chemistry, Analytical
Ruiyue Hu, Feng Zhang, Shengbo Ye, Guangyou Fang
Summary: In this paper, an ultra-wideband and high-gain Vivaldi antenna with artificial electromagnetic material is proposed for ground-penetrating radar systems. The antenna utilizes directors loaded inside the antenna gradient slot and an artificial electromagnetic material composed of H-shaped units to improve gain and radiation directivity. Experimental results show that the antenna has good impedance matching and a maximum realized gain of 15.2 dBi.
Article
Engineering, Electrical & Electronic
Kam Eucharist Kedze, Heesu Wang, Ikmo Park
Summary: This study presents a metasurface-based circularly polarized microstrip patch antenna with high performance in terms of global bandwidth and gain. Through the interaction between the metasurface and the microstrip patch with crossed slot, the antenna achieves wide global bandwidth and stable broadside gain.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Qian Zou, Zhen Gu, Rensheng Xie, Zhongxiang Zhang, Hualiang Zhang, Jun Ding
Summary: In this work, a wideband nonresonant metasurface is proposed to enhance the gain of an ultra-wideband double slot Vivaldi antenna (DSVA). The slots etched on both sides of the ground plane improve the current distribution. The nonresonant metasurface composed of WiFi-shaped unit cells can bend the outgoing wave to the end-fire direction and maintain a high refractive index in the operating bandwidth.
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
(2023)
Article
Optics
Jian-Xiang Zhang
Summary: A new THz polarization beam splitter based on COC photonic crystal fiber with a simple structure is proposed, showing wide bandwidth and high polarization extinction ratios for x and y-polarization modes, suitable for applications in THz communication, imaging, sensing, metrology, and microscopy.
Article
Engineering, Electrical & Electronic
Ya Fei Wu, Yu Jian Cheng, Yi Chen Zhong, Hai Ning Yang
Summary: The paper introduces a method for generating a transverse linearly polarized Bessel beam using a substrate integrated waveguide (SIW) slot array antenna, achieving the desired phase and amplitude distribution. By modulating the offset of the slots and metalized vias, the desired beam can be generated.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Jingjing Wang, Jianwei Liu, Kangming Hou, Yongcheng Li
Summary: A novel antipodal Vivaldi antenna with enhanced gain and directivity is proposed in this paper. The substrate of the antenna is innovated to a combination of circular-shaped and rectangular-shaped. To enhance the gain, a fan-shaped expansion structure is loaded along the opening of the patch, and several directors are loaded in the vertical direction of the substrate to enhance the directivity. The results show that the proposed antenna has a reflection coefficient below -12 dB in the frequency range of 3 to 10 GHz, and the peak gain is higher than 8 dBi after 6 GHz.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Ziheng Zhou, Yue Li, Yijing He, Zhijun Zhang, Pai-Yen Chen
Summary: A special Fabry-Perot (FP) cavity antenna with a slender structure was proposed to achieve omnidirectional radiation pattern with horizontal polarization. The antenna prototype had a length of 2.95 lambda and demonstrated an omnidirectional pattern over the operating band (2.41-2.5 GHz) with high gain and minimal gain variation on the E-plane.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Zichao Zheng, Fangjun Chen, Ziyu Pan, Feng Xu
Summary: In this study, a high-gain and low-profile tapered slot antenna with a composite patch made of ellipse and spoof surface plasmon polaritons (sSPPs) structures is proposed. The fabricated antenna achieves a wide operating bandwidth of 82.3% (5-12 GHz) and shows good directivity and end-fire radiation performance.
ELECTRONICS LETTERS
(2022)
Article
Crystallography
Ammar Armghan, Sunil Lavadiya, Meshari Alsharari, Khaled Aliqab, Malek G. Daher, Shobhit K. Patel
Summary: High-speed wireless communication devices require high-gain, multi-frequency antennas, and the demand for such antennas is increasing. The proposed metamaterial superstrate antenna provides the necessary high gain and multiband performance for high-speed wireless communication devices. The antenna design is also suitable for C- and X-band communication devices and achieves performance optimization through various adjustments. The design exhibits excellent performance in terms of reflection coefficient, directivity, gain, and electric field, and is cost-effective due to the use of FR4 as the dielectric material. A comparison with other articles confirms the novelty of the design, and the proposed method targets applications such as WiFi, Earth observation, and microwave links.
Article
Engineering, Electrical & Electronic
Xiaosong Liu, Zehong Yan, Enlin Wang, Xiaofei Zhao, Tianling Zhang, Fangfang Fan
Summary: This paper presents the design of a novel dual-band dual-beam bifunctional meta-surface with orthogonally polarized characteristics. The proposed reflect-transmit-array is able to reflect x-polarized incidence while transmitting y-polarized incidence and converting it into circularly polarized waves. Experimental results show good performance of the designed prototype.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Chemistry, Applied
Jingjing Liu, Yanlong Huo, Xiaoyan Shi, Zhongqi Liu, Yulong Shan, Yunbo Yu, Wenpo Shan, Hong He
Summary: A series of Ce-Sn catalysts modified with W were prepared and studied for the SCR of NOx by NH3. The Ce-W-Sn catalysts showed higher deNOx efficiency than the Ce-Sn catalysts, and the Ce1W0.24Sn2Ox catalyst prepared by coprecipitation displayed the highest NOx conversion. The mechanism by which W modification improved the structure and function of the Ce1Sn2Oy catalyst was investigated, revealing the promotion of t-Sn(Ce)O2 active phase formation and the inhibition of c-Ce(Sn)O2 phase generation by W species. Additionally, the highly dispersed W species on the Ce1W0.24Sn2Ox catalyst surface formed new Ce-O-W active sites, contributing to enhanced NH3-SCR performance and the suppression of excess NH3 oxidation.
Article
Environmental Sciences
Guangyan Xu, Wenpo Shan, Yunbo Yu, Yulong Shan, Xiaodong Wu, Ye Wu, Shaojun Zhang, Liqiang He, Shijin Shuai, Hailong Pang, Xuefeng Jiang, Heng Zhang, Lei Guo, Shufen Wang, Feng-Shou Xiao, Xiangju Meng, Feng Wu, Dongwei Yao, Yan Ding, Hang Yin, Hong He
Summary: Diesel vehicles in China have caused serious environmental problems, prompting the government to take serious actions against air pollution and impose stricter regulations on diesel vehicle emissions in the latest China VI standard. To comply with these regulations, two major technical routes, EGR and SCR, have been developed for diesel engines. Additionally, complicated aftertreatment technologies, including DOC, DPF, SCR, and ASC, have been developed for emission control. Integration of the aftertreatment system with the engine system is necessary to meet the stringent requirements of the China VI standard, and further upgrades will be needed for near-zero emission targets in the future.
JOURNAL OF ENVIRONMENTAL SCIENCES
(2023)
Article
Chemistry, Physical
Jingjing Liu, Xiaoyan Shi, Yunbo Yu, Mengyuan Zhang, Diru Liu, Hong He
Summary: The HC resistance of CeWSnOx, V2O5-WO3/TiO2, and Cu-SSZ-13 catalysts was studied using propene, toluene, and n-pentane as model HCs. The CeWSnOx catalyst showed much better HC tolerance due to its strong HC oxidation capacity, which inhibited side reactions. In contrast, Cu-SSZ-13 and V2O5-WO3/TiO2 showed undesired HC ammoxidation reactions, especially in the presence of propene.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Chemistry, Physical
Qiaoqi Guo, Ying Luo, Jun Xu, Lidan Deng, Zheng Wang, Hong He
Summary: Photocatalytic conversion of low-concentration CO2 with H2O oxidation is an effective method to achieve sustainable carbon cycling and address the global warming issue. Improving charge separation, surface adsorption, and catalytic process of photocatalysts is crucial to overcome the mass transfer limitation during the conversion of low-concentration CO2. In this study, a highly-crystalline AgxNa1_xTaO3-AgCl heterostructure composite was fabricated, which facilitated the separation and transfer of photogenerated charges. The introduction of Ag cations and AgCl components enhanced the adsorption and activation of CO2 on the surface of the photocatalyst. When combined with metallic Ag cocatalysts, the AgxNa1_xTaO3-AgCl heterostructure photocatalyst exhibited improved activity for CO2 reduction and H2O oxidation at low CO2 concentration conditions. The development of photocatalysts active at low CO2 concentration provides an alternative approach for practical CO2 conversion systems in the future.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Engineering, Environmental
Junlin Chen, Yulong Shan, Yu Sun, Wenqing Ding, Sen Xue, Xuewang Han, Jinpeng Du, Zidi Yan, Yunbo Yu, Hong He
Summary: This study investigated the effects of phosphorus on Cu-SSZ-39 catalysts before and after hydrothermal aging treatment. Phosphorus poisoning significantly decreased the low-temperature NH3-SCR catalytic activity, but this activity loss was alleviated by further hydrothermal aging treatment. Characterization techniques revealed that Cu-P species produced by phosphorus poisoning decreased the redox ability of active copper species, resulting in the observed low-temperature deactivation. However, after hydrothermal aging treatment, Cu-P species partly decomposed, leading to the recovery of low-temperature NH3-SCR catalytic activity.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Maofan Li, Meng Gao, Guangzhi He, Yunbo Yu, Hong He
Summary: Mn doping can significantly enhance the low-temperature NH3-SCR activity of Ce-based oxide catalysts, providing important insights for the development of low-temperature Ce-based catalysts.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Qing Cao, Biwu Chu, Peng Zhang, Qingxin Ma, Jinzhu Ma, Yuan Liu, Jun Liu, Yaqi Zhao, Hong Zhang, Yonghong Wang, Hong He
Summary: The reducibility of SO2 and its acidic products inhibit the production of reactive nitrogen in the photolysis of nitrate, affecting the renoxification process. SO2 has an inhibitory effect on the production of NOx, HONO, and NH3 in the photolysis of ammonium nitrate on different substrates. The interaction between the heterogeneous oxidation of SO2 and nitrate photolysis provides a new perspective on how SO2 affects the photolysis of nitrate absorbed on photoactive oxides.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Soil Science
Na Li, Haibo Du, Mai-He Li, Risu Na, Renkai Dong, Hong S. He, Shengwei Zong, Lirong Huang, Zhengfang Wu
Summary: Global environmental changes have led to the migration of plants into alpine or arctic tundra ecosystems. In the Changbai Mountain, the migration of the low-elevation herb species Deyeuxia angustifolia into the alpine shrubby tundra has resulted in changes in soil properties and soil microbial communities. The upward migration, combined with nitrogen deposition, has altered the soil microbial community composition and led to a shortage of soil phosphorus at higher elevations. These changes may benefit the migration of D. angustifolia and suppress the existing shrubby species.
SOIL BIOLOGY & BIOCHEMISTRY
(2023)
Article
Chemistry, Physical
Qi An, Guangyan Xu, Jianhua Liu, Yingjie Wang, Yunbo Yu, Hong He
Summary: In this study, a bifunctional Pt/Cu-SSZ-13 catalyst with catalytic selectivity and selective catalytic reduction function was successfully prepared. The catalyst exhibited excellent catalytic performance during NH3 oxidation under practical conditions containing water vapor, achieving >85% N2 selectivity over the whole temperature range.
Article
Chemistry, Physical
Shuangye Li, Liyun Song, Jian Li, Hong He
Summary: A series of NdV/Ti-x% catalysts were prepared by a microwave-assisted deposition-precipitation method and their catalytic performance for the selective catalytic reduction (SCR) of NO by NH3 was investigated. The amount of vanadate added significantly influenced the SCR activity of the catalyst. The NdV/Ti-x% catalysts demonstrated good low-temperature catalyst activities and excellent SO2 resistance performances.
Article
Engineering, Environmental
Zhuocan Li, Meng Gao, Zhihui Lv, Rucheng Duan, Yulong Shan, Hongwei Li, Guangzhi He, Hong He
Summary: This study reveals the active sites and working principle of commercial vanadium oxide catalysts in the fast SCR reaction through experimental and computational methods. It demonstrates that polymeric vanadyl species act as the main active sites and provides a fundamental basis for developing high-efficiency and low V2O5-loading SCR catalysts.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Review
Multidisciplinary Sciences
Yuan Liu, Guangzhi He, Biwu Chu, Qingxin Ma, Hong He
Summary: Soot particles, consisting of elemental carbon and organic compounds, have significant impacts on climate, the environment, and human health. They are chemically and physically active in atmospheric aging processes, leading to changes in composition, morphology, hygroscopicity, and optical properties. The interactions between soot and atmospheric substances, as well as the heterogeneous reactions on soot, have been extensively studied to better understand the environmental behaviors of soot.
FUNDAMENTAL RESEARCH
(2023)
Article
Environmental Sciences
Zhihua Liu, Wen J. Wang, Ashley Ballantyne, Hong S. He, Xugao Wang, Shuguang Liu, Philippe Ciais, Michael C. Wimberly, Shilong Piao, Kailiang Yu, Qichao Yao, Yu Liang, Zhiwei Wu, Yunting Fang, Anping Chen, Wenru Xu, Jiaojun Zhu
Summary: According to satellite data, the rate, frequency, and extent of forest disturbances in China decreased from 1986 to 2020, possibly due to forest protection policies. However, while these disturbances intensified in the southeast, they weakened in the northeast.
COMMUNICATIONS EARTH & ENVIRONMENT
(2023)
Article
Meteorology & Atmospheric Sciences
Yuanyuan Fu, Chang Liu, Hong He, Shaoqiang Wang, Lunche Wang, Zhijie Xie
Summary: Exploring spring phenology dynamics in the Greater Khingan Mountains, Northeast China, we found that preseason temperature strongly influenced the start of the growing season (SOS), while the effects of preseason precipitation and radiation varied by region. The SOS dates showed regional characteristics, with a gradual delay from north to south.
INTERNATIONAL JOURNAL OF CLIMATOLOGY
(2023)
Article
Engineering, Environmental
Zhi Liu, Yingsheng An, Guangyan Xu, Yunbo Yu, Hong He
Summary: The mechanistic cause of the enhancement of the C3H6-SCR activity of Ag/Al2O3 by trace Pd doping and the corresponding structure-property relationship were investigated. Pd doping enhanced the water resistance of Ag/Al2O3 for C3H6-SCR by changing the reaction pathway. Under wet conditions, a series of in situ DRIFT studies indicated that the production of an active acetate intermediate on Ag/Al2O3 was suppressed during the partial oxidation of C3H6, while trace Pd doping promoted the formation of another active intermediate, an enolic species. Furthermore, a pathway for the formation of enolic species by the reaction of acrylate with hydroxyl species was proposed. DFT calculations revealed that the surface of Ag clusters was easily covered by hydroxyl in the presence of water vapor, which could inhibit the formation of acetates. Doping with Pd facilitated the activation of acrylate which might further react with hydroxyl species to form enolic species. These findings can be helpful for the future design of efficient HC-SCR catalysts.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
