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1,438 results on '"Zhang, Guobin"'

204. Statistical investigation on the coupling mode characteristics of a blade-disk-shaft unit.

Author

She, Houxin, Li, Chaofeng, Zhang, Guobin, and Tang, Qiansheng

Subjects
MONTE Carlo method, DISTRIBUTION (Probability theory), MODE shapes
Abstract

The coupling vibration of a blade-disk-shaft unit is generally studied on the assumption that all the blades are identical. However, the mistuning feature always occurs due to manufacturing tolerances and other reasons in engineering practice. Therefore, a shaft-disk-blades coupling model with the random mistuning feature is derived based on our previous work. Then the statistical analysis on vibration characteristics of a blade-disk-shaft unit is performed. The uncertainty effects of blade parameters on coupling characteristics between the subcomponents are exhibited. The Monte Carlo simulation and statistical theory are used to capture the probability distributions of coupling characteristics. The natural frequency distributions of coupling modes are obtained under different mistuning levels and evaluated through confidence intervals. Then the mode shapes, obtained by eigenvector, are plotted to derive the evolution law of coupling mode type in a random mistuning system. At last, the localization factor is defined, then its statistical results are obtained to evaluate the mode localization magnitude under different mistuning levels. [ABSTRACT FROM AUTHOR]

Published
2023
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207. Foliar Spraying of NaHS Alleviates Cucumber Salt Stress by Maintaining N + /K + Balance and Activating Salt Tolerance Signaling Pathways.

Author

Luo, Shilei, Liu, Zeci, Wan, Zilong, He, Xianxia, Lv, Jian, Yu, Jihua, and Zhang, Guobin

Subjects
CUCUMBERS, HYDROGEN sulfide, CELLULAR signal transduction, SALT, LEAF area, MITOGEN-activated protein kinases, ION transport (Biology)
Abstract

Hydrogen sulfide (H2S) is involved in the regulation of plant salt stress as a potential signaling molecule. This work investigated the effect of H2S on cucumber growth, photosynthesis, antioxidation, ion balance, and other salt tolerance pathways. The plant height, stem diameter, leaf area and photosynthesis of cucumber seedlings were significantly inhibited by 50 mmol·L−1 NaCl. Moreover, NaCl treatment induced superoxide anion (O2·−) and Na+ accumulation and affected the absorption of other mineral ions. On the contrary, exogenous spraying of 200 μmol·L−1 sodium hydrosulfide (NaHS) maintained the growth of cucumber seedlings, increased photosynthesis, enhanced the ascorbate–glutathione cycle (AsA–GSH), and promoted the absorption of mineral ions under salt stress. Meanwhile, NaHS upregulated SOS1, SOS2, SOS3, NHX1, and AKT1 genes to maintain Na+/K+ balance and increased the relative expression of MAPK3, MAPK4, MAPK6, and MAPK9 genes to enhance salt tolerance. These positive effects of H2S could be reversed by 150 mmol·L−1 propargylglycine (PAG, a specific inhibitor of H2S biosynthesis). These results indicated that H2S could mitigate salt damage in cucumber, mainly by improving photosynthesis, enhancing the AsA–GSH cycle, reducing the Na+/K+ ratio, and inducing the SOS pathway and MAPK pathway. [ABSTRACT FROM AUTHOR]

Published
2023
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218. A selection scheme for energy storage to participate in primary frequency regulation of new energy

Author

Zhao, Song, primary, Li, Rongli, additional, Zhao, Wei, additional, Zhou, Lei, additional, Li, Xu, additional, Yu, Haicun, additional, Zhang, Qian, additional, Du, Ronghua, additional, Huo, Hongyan, additional, Dang, Shaojia, additional, Xin, Xiaogang, additional, Zhang, Guobin, additional, Guo, Ruijun, additional, and Yin, Jianhua, additional

Published
2022
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225. Exhaustive Drainage versus Fixed-time Drainage for Chronic Subdural Hematoma after One-burr Hole Craniostomy (ECHO): Study Protocol for a Multicenter Randomized Controlled Trial

Author

Wu, Liang, primary, Ou, Yunwei, additional, Zhu, Bingcheng, additional, Guo, Xufei, additional, Yu, Xiaofan, additional, Xu, Long, additional, Li, Jinping, additional, Feng, Enshan, additional, Li, Huaqing, additional, Wang, Xiaodong, additional, Chen, Huaqun, additional, Sun, Zhaosheng, additional, Liu, Zaofu, additional, Yang, Dawei, additional, Zhang, Hongbing, additional, Liu, Zhigang, additional, Tang, Jie, additional, Zhao, Shangfeng, additional, Zhang, Guobin, additional, Yao, Jiemin, additional, Ma, Dongming, additional, Sun, Zelin, additional, Zhou, Hui, additional, Liu, Baiyun, additional, and Liu, Weiming, additional

Published
2022
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230. Dynamic modeling and simulation of a novel mechanism for adhesive capture of space debris

Author

Zhiwei Feng, Zhang Guobin, Chen Qingquan, Tao Yang, and Qingbin Zhang

Subjects
Atmospheric Science, Computer simulation, Computer science, Process (computing), Aerospace Engineering, Mechanical engineering, Astronomy and Astrophysics, Multibody system, System dynamics, Mechanism (engineering), Geophysics, Space and Planetary Science, Robustness (computer science), General Earth and Planetary Sciences, Beam (structure), Space debris
Abstract

Flexible capture has high applicability in the removal of space debris. In this paper, a novel adhesive capture mechanism is proposed, the multibody dynamic modeling method of the capture system is detailed, and an investigation of the adhesive capture process by numerical simulation is presented. First, the passive trigger mechanism of the capture device is described. Second, based on the classical rigid body mechanics and the fully parameterized ANCF beam element, the multibody model of the capture device is detailed. A contact detection algorithm is proposed to take the failure of adhesive connection into account, and its robustness and effectiveness are demonstrated. Finally, investigations of the dynamics during the capture process in two typical capture conditions are described and the impact of some system parameters on the capture effectiveness is discussed. The simulation results provide key parameters for the selection of the adhesive material and show the practical applicability of the capture mechanism.

Published
2021

247. Decoration of NiFe‐LDH Nanodots Endows Lower Fe‐d Band Center of Fe1‐N‐C Hollow Nanorods as Bifunctional Oxygen Electrocatalysts with Small Overpotential Gap.

Author

Liu, Zheng‐Qi, Liang, Xiongyi, Ma, Fei‐Xiang, Xiong, Yu‐Xuan, Zhang, Guobin, Chen, Guohua, Zhen, Liang, and Xu, Cheng‐Yan

Subjects
OXYGEN reduction, OXYGEN evolution reactions, ELECTROCATALYSTS, NANODOTS, NANORODS, OVERPOTENTIAL, STANDARD hydrogen electrode, POWER density, HYDROGEN evolution reactions
Abstract

Single‐atom Fe‐N‐C (denoted as Fe1‐N‐C) catalysts exhibit inadequate bifunctional activities to conquer the sluggish oxygen reduction and evolution reaction (ORR/OER), hindering their practical applications in rechargeable Zn‐air batteries (ZABs). Here, by employing Fe1‐N‐C hollow nanorods as ORR‐active support, OER‐active NiFe‐layered double hydroxide (NiFe‐LDH) nanodots are evenly decorated through a spatially confined process to form NiFe‐LDH/Fe1‐N‐C heterostructure hollow nanorods with abundant accessible catalytic sites. The NiFe‐LDH/Fe1‐N‐C heterostructure not only enhances the ORR activity of pristine Fe1‐N‐C but also realizes efficient bifunctional ORR/OER activity in one monolithic catalyst. Theoretical calculations reveal that introducing NiFe‐LDH nanodots results in donation of electrons to the Fe1‐N‐C matrix and thus lowers the Fe‐d band center of the Fe‐N4 sites, dramatically narrowing the energy barriers of the ORR rate‐limiting steps. As a result, NiFe‐LDH/Fe1‐N‐C nanorods deliver remarkable ORR activity with a half‐wave potential of 0.90 V versus reversible hydrogen electrode, surpassing bare Fe1‐N‐C and commercial Pt/C. Impressively, the integrated NiFe‐LDH/Fe1‐N‐C catalysts show outstanding bifunctional performance with a small overpotential gap of only 0.65 V. The liquid‐state ZABs with NiFe‐LDH/Fe1‐N‐C as an air‐cathode catalyst deliver a peak power density of 205 mW cm−2 and long‐term cycling stability of up to 400 h. [ABSTRACT FROM AUTHOR]

Published
2023
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250. Temporal Variation of Airborne Dust Concentrations in the Mogao Grottoes, Dunhuang, China

Author

Zhang, Guobin, Tan, Lihai, Zhang, Weimin, Zhan, Hongtao, and Qiu, Fei

Subjects
General Environmental Science
Abstract

Dust storms bring a large quantity of dust aerosols from arid and semi-arid regions of the Earth. However, real-time dust concentration data for dust storms in arid regions, important for wind erosion studies, are still limited. Here, temporal variation of airborne dust concentrations in the Mogao Grottoes, Northwest China, during the monitoring period from February to October 2012 and typical dust storms under different wind directions were analyzed. Results reveal that the monthly mean total suspended particle (TSP), particulate matter less than 10 μm (PM10), and particulate matter less than 2.5 μm (PM2.5) concentrations gradually decreased from February to October. The daily mean dust concentrations fluctuated with the day, with extreme values occurring mainly on February, March, and April. The daily mean PM10/TSP ratio ranged from 0.67 to 0.98 (mean of 0.82), and the PM2.5/PM10 ratio ranged from 0.31 to 0.73 (mean of 0.55), indicating PM10 dominated in TSP. In typical dust storms, the maximum real-time concentrations can reach 16, 000–21, 000 μg TSP m−3, ∼11, 000 μg PM10 m−3, and 3000–3500 μg PM2.5 m−3, and extreme real-time dust concentrations of 50358.03 μg TSP m−3, 33100.86 μg PM10 m−3, and 7502.59 μg PM2.5 m−3 were recorded. Coincidence of the dry climate and windy season and sufficient dust sources in the surrounding environment contributed to the high dust concentrations in the Mogao Grottoes. To achieve the goal of minimizing the damage of falling dust to the murals and statues, establishing a dust storm early warning system and improving the existing sand control system are recommended.

Published
2022

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