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143 results on '"Shi, Kunpeng"'

2. Hankel Spectrum Analysis: A novel signal decomposition method and its geophysical applications

Author

Shi, Kunpeng and Ding, Hao

Subjects
Physics - Geophysics, Nonlinear Sciences - Chaotic Dynamics, Physics - Applied Physics
Abstract

To analyze non-stationary harmonic signals typically contained in geophysical observables is a quest that has seen continual advances in numerical techniques over the decades. In this paper, based on transient z-pole estimation (in Hankel matrices), a novel state-space analysis referred to as Hankel Spectral Analysis (HSA), was developed. Depended on the Hankel total least square (HTLS), the HSA incorporates truncated singular value decomposition (TSVD) and its shift-invariant property in robustly decomposing the closely-spaced sinusoids. Resorted to a sliding window processing, HSA can be used to analyze non-stationary sequential structures, in the support of consecutive quaternary parameters {Ai, {\alpha}i, fi, {\theta}i}. Based on a series of experiments with special features commonly in real measurements, the availabilities of HSA in complex harmonic constituents (e.g., the time-variant amplitude/frequency, mutation, the episodic recording signals) with low Signal-to-Noise Ratio are confirmed. In real applications, we use HSA to analyze both global geophysical observables, including polar motion (PM) and earth's dynamic oblateness ({\Delta}J2), and some new findings are obtained. In the PM series since the 1900s, a total of triple jumps from Chandler wobble (CW) are firstly confirmed; and all of them are synchronized by the sharp decrease of Chandler intensity and period. In the {\Delta}J2 series, two decadal signals (18.6 yr, 10.5 yr) are identified to be associated with the tide effect, and solar activity; and its interannual-to-decadal oscillations contribute to multiple global gravity anomalies. These findings implied the great potential of the HSA in searching hitherto signals of geophysical observations., Comment: 40 pages,10 figures

Published
2022

26. Analysis of Strength Characteristics and Energy Dissipation of Improved-Subgrade Soil of High-Speed Railway above Mined-Out Areas

Author

Wang, Shuren, Shi, Kunpeng, Chen, Yubo, Zahng, Jiyun, and Li, Chunliu

Subjects
dynamic test, energy dissipation, high-speed railway, mined-out area, subgrade soil
Abstract

To reveal the effect of sand content on the mechanical performance and energy dissipation of cement improved subgrade soil, using universal testing machine and SHPB test device, unconfined compressive strength (UCS) and impact compression strength under different impact load (0.2, 0.3, 0.4, and 0.5 MPa) were carried out for the cement improved subgrade soil with different sand content (0%, 5%, 10%, 15%, and 20%). Results show that the dynamic and static stress-strain curves of the cement improved soil have similar variation trend. With the increase of the sand content, the UCS and impact compressive strength of the cement improved soil both increase first, then decrease later, showing the form of a quadratic function. The strength growth rate and the dynamic increase factor (DIF) reach the maximum values when the sand content is 10%, which is 64.7% and 18.6% larger than that of ordinary improved subgrade soil, respectively. In addition, when the sand content increases from 0% to 20%, the specific dissipation energy increases first, and decreases later. Mixing 10% natural sand is the optimal proportion to obtain better energy dissipation capacity of the sand-cement-improved soil.

Published
2023

27. Cumulative Deformation Analysis of Foundation of Mined-Out Areas under Dynamic Loading - a Case Study of Taijiao High-Speed Railway

Author

Shi, Kunpeng, Wang, Shuren, Chen, Yubo, Yang, Wenfu, and Li, Chunliu

Subjects
cumulative deformation, dynamic loading, foundation, high-speed railway, mined-out areas
Abstract

Since there is a safety risk of cumulative deformation exceeding the limit when high-speed rail passes through the mined-out areas, for the special needs of risk control along the high-speed railway, taking the foundation of the mined-out areas of Dianshang coal mine under Taijiao high-speed railway as the background, the mechanical model of rotation structure of key block was established. The stability criterion of fracture structure rock of the mined-out area was proposed. Using self-developed similar model test and dynamic loading device, the evolution characteristics and deformation mechanism of foundation of the mined-out areas under long-term dynamic loading of the high-speed railway were analyzed. Results show that when the number of loading vibration exceeds 5 million times, the foundation of the mined-out areas will occur over all settlement and deformation. The cumulative deformation of the foundation in different buried depths has similar variation law with the increasing of excitation and all experience three stages: the slow growth stage, the fast growth stage, and the stable stage. The prediction model of cumulative deformation of the foundation of the mined-out areas with different damage degrees under the long-term dynamic loading was proposed. The model parameters are closely related to the damage degree of foundation of the mined-out areas. The conclusions obtained in this study provide a theoretical basis for the prediction and control of the cumulative deformation of the foundation of the mined-out areas under the dynamic loading of high-speed railway.

Published
2023

32. Acute damage from the degradation of Ulva prolifera on the environmental microbiota, intestinal microbiota and transcriptome of Japanese flounder Paralichthys olivaceus

Author

Fan, Qingxin, primary, Shi, Kunpeng, additional, Zhan, Min, additional, Xu, Qian, additional, Liu, Xinbao, additional, Li, Zhujun, additional, Liu, Hongning, additional, Xia, Yanting, additional, Chen, Yadong, additional, Shi, Xiaoyong, additional, and Sha, Zhenxia, additional

Published
2022
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41. Experimental research on the wall-wetting effects on the frictional property of the cylinder liner–piston ring pair.

Author

Xu, Bo, Yin, Bifeng, Jia, Hekun, Wei, Mingliang, and Shi, Kunpeng

Abstract

The application of novel injection strategies (high-pressure injection, early injection, retarded injection, etc.) in combustion engines has made the wall-wetting problem severer. As the splashed fuel dilutes the lubricating oil, the tribological performance of the cylinder liner–piston ring pair will be affected. In this research, the viscosity and wettability tests were conducted firstly by mixing diesel into lubrication oil. It was found that the dynamic viscosity of the mixture drops with more fuel diluting the oil, and a small quantity of diesel mixed will cause a remarkable decline in lubricant viscosity; also, the contact angle shows a downward trend with the increasing diluting ratio. Then based on several typical diluting ratios, the reciprocating friction tests were carried out to measure the instantaneous friction force of the production ring/liner pair. The experimental results showed that under a mixed lubrication state, the peak friction force of the ring/liner pair occurs around the dead centers, while the minimum force occurs at the middle position of the reciprocating stroke; with more fuel diluting the oil, the bearing capacity of oil film degrades, resulting in the increase of friction force. In addition, the average friction coefficient of the ring/liner pair shows an upward trend with the increasing diluting ratio, and the Stribeck curve moves toward the upper-left, which means the lubrication condition of this pair tends to transit from mixed lubrication to boundary lubrication, causing negative effects on the frictional property of the cylinder liner–piston ring pair. Therefore, the diluting ratio should be controlled under 20%. [ABSTRACT FROM AUTHOR]

Published
2022
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43. Acute Damage of the Decomposition of Ulva. Prolifera on the Environmental Microbiota, Intestinal Microbiota and Transcriptome of Japanese Flounder Paralichthys Olivaceus

Author

Fan, Qingxin, primary, Shi, Kunpeng, additional, Zhan, Min, additional, Xu, Qian, additional, Liu, Xinbao, additional, Li, Zhujun, additional, Liu, Hongning, additional, Xia, Yanting, additional, Chen, Yadong, additional, Shi, Xiaoyong, additional, and Sha, Zhenxia, additional

Published
2021
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47. Association between MyoG Gene Polymorphism and Egg Quality of Egg Quail

Author

Yang Shuai, Shi KunPeng, Wu XiaoHong, Fan HongDeng, Bai JunYan, Fu XueYan, Cao Heng, and Pang YouZhi

Subjects
Andrology, Genetic marker, biology.animal, Genotype, Animal Science and Zoology, Single-nucleotide polymorphism, Gene polymorphism, Allele, Biology, Allele frequency, Gene, Quail
Published
2020

48. Stability Analysis of Middle Rock Pillar and Cross - S ection Optimi z ation for Ultra - Small Spacing Tunnel s

Author

Chen Wenxue, Liu Shiping, Wang Shuren, and Shi Kunpeng

Subjects
0211 other engineering and technologies, General Engineering, Pillar, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Stability (probability), Cross section (physics), lcsh:TA1-2040, lcsh:Technology (General), lcsh:T1-995, Geotechnical engineering, lcsh:Engineering (General). Civil engineering (General), Geology, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences
Published
2018

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