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Waveform inversion and analysis of an unusual earthquake swarm in the Boshan mining area, Shandong Province, China

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Earthquake Science 2016年第1期29卷 1-15页

作者： Jian-Chang Zheng Jin-Hua Zhao Chang-peng xu peng Wang Earthquake Administration of Shandong Province Jinnan 250014China

Moment tensor solutions were retrieved for the earthquake swarm that occurred during November and December 2010 in the Boshan mining area, Shandong Province, China. The results showed that the double-couple components in the source mechanisms were higher at the beginning of the swarm and consisted mainly of shear faulting controlled by tectonic stress. The subsequent events had significant non-double-couple components, indicating tensile faulting. The double-couple components predominately presented as normal faulting and the P axes were orientated almost vertically. The slip vectors of the swarm events were relatively stable. With reference to the tectonic features near the epicenter, we concluded that the swarm was a result of subordinate fault motion related to the Wangmu Mountain fault and that high-pressure pore fluids played a crucial role in the activity of the earthquake swarm.

关键词： Moment tensor - Tensile crack Mechanism Boshan earthquake swarm Pore pressure

On-site variety discrimination of tomato plant using visible-near infrared reflectance spectroscopy

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第2期10卷 126-132页

作者： Hui-rong xu peng YU Xia-ping FU Yi-bin YING College of Biosystems Engineering and Food Science Zhejiang University Hangzhou 310029 China

The use of visible-near infrared (NIR) spectroscopy was explored as a tool to discriminate two new tomato plant varieties in China (Zheza205 and Zheza207). In this study, 82 top-canopy leaves of Zheza205 and 86 top-canopy leaves of Zheza207 were measured in visible-NIR reflectance mode. Discriminant models were developed using principal component analysis (PCA), discriminant analysis (DA), and discriminant partial least squares (DPLS) regression methods. After outliers detection, the samples were randomly split into two sets, one used as a calibration set (n=82) and the remaining samples as a validation set (n=82). When predicting the variety of the samples in validation set, the classification correctness of the DPLS model after optimizing spectral pretreatment was up to 93%. The DPLS model with raw spectra after multiplicative scatter cor- rection and Savitzky-Golay filter smoothing pretreatments had the best satisfactory calibration and prediction abilities (correlation coefficient of calibration (Rc)=0.920, root mean square errors of calibration=0.196, and root mean square errors of predic- tion=0.216). The results show that visible-NIR spectroscopy might be a suitable alternative tool to discriminate tomato plant varieties on-site.

关键词： Visible-NIR spectroscopy Tomato plant variety Discrimination Principal component analysis (PCA) Discriminant analysis (DA) Discriminant partial least squares (DPLS)

Thermodynamic optimization and fluid selection of organic Rankine cycle driven by a latent heat source

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Journal of Central South University 2017年第12期24卷 2829-2841页

作者： xu peng LU Jian LI Tai-lu ZHU Jia-ling School of Energy and Safety Engineering Tianjin Chengjian University Tianjin 300384 China Key Laboratory of Efficient Utilization of Low and Medium Grade Energy Ministry of Education(Tianjin University) Tianjin 300072 China

Organic Rankine cycle(ORC) is applicable for the heat-work conversion. Whereas, there also exist a lot issues that influence the efficiency and the cost of the system. In this work, eleven pure working fluids(as categorized into alkanes, and fluorinated alkanes) are investigated based on the first and second law of thermodynamics. The major objective is to obtain the most suitable working fluid for the latent heat source. The results show that the working fluid is an important factor of the system performance. The heat absorption of the working fluid in the evaporator is inversely proportional to the evaporating temperature, but the thermal and exergetic efficiencies are just the opposite. RC318 has the highest net power output and the lowest outlet temperature of the heat source, but its global warming potential(GWP) value is too high. The cyclohexane shows the highest thermal efficiency among the fluids investigated. Moreover, the figure of merit(FOM) of the isobutane is higher than that of other working fluids. Overall, the cyclohexane shows that the optimal comprehensive performance is more feasible for medium grade heat source in engineering applications.

关键词： organic Rankine cycle working fluids thermodynamics low-temperature evaporating temperature

Characterization and source identification of submicron aerosol dur ing ser ious haze pollution periods in Beijing

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Journal of Environmental Sciences 2022年第2期34卷 25-37页

作者： peng xu Yuan Yang Junke Zhang Wenkang Gao Zirui Liu Bo Hu Yuesi Wang State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Resource and Environmental Engineering Guizhou UniversityGuiyang 550025GuizhouChina Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu 611756China University of the Chinese Academy of Sciences Beijing 100049China

Submicron aerosol is of extensive concern not only due to its significant impact on air quality but also because it is detrimental to human *** this study,we investigated the characteristics,sources and chemical processes of submicron aerosol based on realtime online measurements of submicron aerosols(NR-PM 1)during December 2015 at an urban site in *** average mass concentration of NR-PM 1 was 92.5±84.9μg/m^(3),the hourly maximum was 459.1μg/m^(3) during the entire *** organic aerosol(OA)(55%)was the largest contributor to NR-PM *** average mass concentration of PAHs was 0.217±0.247μg/m^(3),exhibiting the highest concentration at night and the lowest levels in the *** average mass concentration of organic nitrate was 2.52±2.36μg/m^(3) and that of inorganic nitrate was 7.62±8.22μg/m^(3),accounting for 36%and 64%,respectively,of the total nitrate *** matrix factorization(PMF)differentiated the OA into five chemical components including LV-OOA,SV-OOA,COA,HOA and CCOA,accounting for 22%,16%,13%,25%and 24%respectively,of the total *** average NR-PM 1 mass concentration on the heavy polluted days(HPD)was 182.8±70.2μg/m^(3),which was approximately 9 times that on clean days(CD).The enhanced secondary formation of SNA was evident on HPD,especially the rapid increase of sulfate(23%)and nitrate(19%).

关键词： Haze pollution Submicron aerosol Source apportionment PAHs Organic and inorganic nitrate

Study of ghost image suppression in polarized catadioptric virtual reality optical systems

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Virtual Reality & Intelligent Hardware 2020年第1期2卷 70-78页

作者： xu peng Zhenyu GAO Yitong DING Dongfeng ZHAO Xiaoyu CHI School of Instrumentation and Optoelectronic Engineering Qingdao Research Institute of Beihang UniversityQingdao 266100China Goertek Co. Ltd.Qingdao 266100China

Backgrounds This paper introduces a polarized catadioptric virtual reality optical *** a focus on the issue of serious ghost image in the system,root causes are analyzed based on design principles and optical *** The distribution of stray light is simulated using Lighttools,and three major ghost paths are selected using the area of the diffuse spot,S d and the energy ratio of the stray light,K as evaluation means.A method to restrain the ghost image through optimization of the structure of the optical system by controlling the focal power of the ghost image path is ***/Conclusions The results show that the S_(d) for the ghost image path increases by 40%and K decreases by 40%after *** image is effectively suppressed,which provides the theoretical basis and technical support for ghost suppression in a virtual reality optical system.

关键词： Virtual Reality Optical System Ghost Focal power Optical Design

BIM-based automated design for HVAC system of office buildings-An experimental study

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Building Simulation 2022年第7期15卷 1177-1192页

作者： Hongxin Wang peng xu Huajing Sha Jiefan Gu Tong Xiao Yikun Yang Dingyi Zhang School of Mechanical Engineering Tongji University1239 Siping RoadShanghaiChina College of Food Science and Technology Shanghai Ocean UniversityShanghai201306China

Although computer technologies have greatly advanced in recent years and help engineers improve work efficiency,the heating,ventilation,and air conditioning(HVAC)design process is still very *** this paper,we propose a conceptual framework for automating the entire design process to replace current human-based HVAC design *** framework includes the following automated processes:building information modeling(BIM)simplification,building energy modeling(BEM)generation&load calculation,HVAC system topology generation&equipment sizing,and system diagram *** this study,we analyze the importance of each process and possible ways to implement them using ***,we use a case study to test the automated design procedure and illustrate the feasibility of the new automated design *** purpose of this study is to simplify the steps in the traditional rule-based HVAC system design process by introducing artificial intelligence(Al)technology based on the traditional computer-aided design(CAD)*** results show that the automatic processes are feasible,compared with the traditional design process can effectively shorten the design time from 23.37 working hours to nearly 1 hour,and improve the efficiency.

关键词： BIM BEM HVAC system automated design

Biological analysis of woodpecker’s brain after impact experiments

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Science China(Technological Sciences) 2021年第5期64卷 1101-1106页

作者： xu peng NI YiKun LIU JingLong ZHANG WeiRong LIU SiJian WANG LiZhen FAN YuBo Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Centre for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing 100083China

Woodpeckers can withstand a fierce impact during *** studies have focused on the biomechanical analysis of the pecking process,the properties of the beak and hyoid bone of woodpecker;however,the biological characteristics of the woodpecker brain are also important in resisting impact *** employed impact experiments and biological analysis in normal and injured brains to reveal the impact-resistant biological characteristics of woodpecker brains,as well as the impact energy’s biological effects on the woodpecker *** hoopoe,which has a similar size but only a slight pecking behavior,was selected as the control group to compare brain morphology and neuronal cells differences in normal brains between woodpecker and hoopoe by sectioning and staining.A loading device was designed to conduct a quantifiable impact energy to the woodpeckers’*** groups of woodpeckers were impacted with the same energy on the forehead,beak,tempus and occiput,*** changes in the injured brains were evaluated by Nissl staining and enzyme-linked immunosorbent *** results showed that:(1)woodpeckers had a larger cerebellum and a higher density of Nissl bodies than hoopoe;(2)Nissl apoptosis appeared in the brain samples after the forehead and the occiput impact experiments,but no obvious Nissl body apoptosis was observed after impact on the tempus and the beak;(3)β-amyloid protein accumulated in the normal status woodpecker *** study reveals that:woodpecker brain morphology is well-adapted to impact,woodpecker heads display location-dependent protective performance,with beak and tempus regions having a better protective performance than the forehead and occiput,Nissl apoptosis appears in injured woodpecker brains,and that the accumulation ofβ-amyloid protein does not show a direct relationship with the injury state of woodpecker’s brain tissue in our study.

关键词： woodpecker biomechanics impact experiments impact resistance biological analysis

A dural substitute based on oxidized quaternized guar gum/porcine peritoneal acellular matrix with improved stability, antibacterial and anti-adhesive properties

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Chinese Chemical Letters 2023年第3期34卷 424-429页

作者： Xiaoshuang Yu pengfei Yue xu peng Hongmei Ding Ningning Lei Xixun Yu College of Polymer Science and Engineering Sichuan UniversityChengdu 610065China West China Hospital of Sichuan University Department of BiotherapyCancer CenterState Key Laboratory of BiotherapyChengdu 610041China Experimental and Research Animal Institute Sichuan UniversityChengdu 610065China

Trauma and neurosurgery often result in dural defects and are followed by serious complications or even death, finding suitable dural replacement materials to repair the defective dura has important clinical significance. Porcine peritoneal acellular matrix(PPAM) is a promising alternative material, but its poor stability makes it difficult to meet the various needs of dural reconstruction. In this work, we developed a novel antibacterial cross-linking agent oxidized quaternized guar gum(OQGG) and used it for the first time to stabilize PPAM to construct a dural mater substitute(OQGG-PPAM). The results showed that 1.5%OQGG-PPAM presented suitable mechanical property as well as good thermal stability and resistance to enzymatic degradation. It also exhibited good antibacterial activity and good anti-leakage ability. Furthermore, 1.5% OQGG-PPAM not only exhibited excellent cell compatibility but also significantly stimulated the secretion of b FGF and VEGF from seeded cells which was convenient for dural remodeling. In vivo experiment, it also exhibited the excellent histocompatibility and good anti-adhesion property. This study showed that OQGG can be used as a novel antibacterial cross-linking reagent for crosslinking natural tissues and 1.5% OQGG-PPAM was a potential candidate material for dura mater substitute.

关键词： Oxidized quaternized guar gum Dural substitute Porcine peritoneal acellular matrix Antibacterial

SDC-DeepLabv3+:Lightweight and Precise Localization Algorithm for Safflower-Harvesting Robots

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Plant Phenomics 2024年第3期6卷 621-637页

作者： Zhenyu Xing Zhenguo Zhang Yunze Wang peng xu Quanfeng Guo Chao Zeng Ruimeng Shi College of Mechanical and Electrical Engineering Xinjiang Agricultural UniversityUrumqi 830052China Key Laboratory of Intelligent Equipment and Robotics for Agriculture of Zhejiang Province Hangzhou 310058China Key Laboratory of Xinjiang Intelligent Agricultural Equipment Urumqi 830052China

Harvesting robots had difficulty extracting filament phenotypes for small,numerous filaments,heavy cross-obscuration,and similar phenotypic characteristics with *** experience difficulty in localizing under near-colored backgrounds and fuzzy contour *** cannot accurately harvest filaments for ***,a method for detecting and locating filament picking points based on an improved DeepLabv3+algorithm is proposed in this study.A lightweight network structure,ShuffIetNetV2,was used to replace the backbone network Xception of the traditional DeepLabv3+.Convolutional branches for 3 different sampling rates were added to extract information on the safflower features under the receptive *** block attention was incorporated into feature extraction at the coding and decoding layers to solve the interference problem of the near-color background in the feature-fusion ***,using the region of interest of the safflower branch obtained by the improved DeepLabv3+,an algorithm for filament picking-point localization was designed based on barycenter *** tests demonstrated that this method was capable of accurately localizing the *** mean pixel accuracy and mean intersection over union of the improved DeepLabv3+were 95.84%and 96.87%,*** detection rate and weights file size required were superior to those of other *** the localization test,the depth-measurement distance between the depth camera and target safflower filament was 450 to 510 mm,which minimized the visual-localization *** average localization and picking success rates were 92.50%and 90.83%,*** results show that the proposed localization method offers a viable approach for accurate harvesting localization.

关键词： lightweight localization algorithm harvesting precise robots safflower sdc-deeplabv3+