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A comparison between artificial neural network algorithms and empirical equations applied to submerged weir scour evolution prediction

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International Journal of Sediment Research 2023年第1期38卷 105-114页

作者： dawei guan Jingang Liu Yee-Meng Chiew Jian-Hao Hong Liang Cheng Key Laboratory of Ministry of Education for Coastal Disaster and Protection Hohai University School of Civil and Environment Engineering Nanyang Technological University Sustainability Center Nanhua University School of the Environment and Safety Engineering Jiangsu University

Estimating the time evolution of a local scour hole downstream of submerged weirs can help determine the maximum scour depth and length and is essential to designing submerged weir foundations.In the current study, artificial neural networks with a backpropagation learning algorithm were used to estimate the temporal variation of scour profiles downstream of submerged weirs under clear water conditions. Physical factors, such as the flow condition, weir size, and sediment characteristics, are general scour considerations. Two sets of data combinations, namely original and non-dimensional data, were utilized in developing the backpropagation network(BPN) model. Using the data combinations and a trial-and-error method, the appropriate number of hidden neurons in the model architecture was determined. The results indicated that using non-dimensional variables as inputs in estimating the time evolution of scour holes downstream of a submerged weir is more suitable for the BPN model. Comparisons of the prediction results of the BPN model and an empirical regression formula revealed that the BPN model was more accurate and more direct in predicting the temporal variation of the local scour hole profile. In addition, sensitivity analysis showed that the dimensionless time exerted the most significant impact on the time evolution of the non-dimensional scour hole profile.

关键词： Submerged weir Scour profile Artificial neural networks (ANNs) Time evolution Backpropagation

DNA degradation within mouse brain and dental pulp cells 72 hours postmortem

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Neural Regeneration Research 2012年第4期7卷 290-294页

作者： Jilong Zheng Xiaona Li Di Shan Han Zhang dawei guan School of Forensic Medicine China Medical University Shenyang 110001 Liaoning Province China School of Forensic Medicine China Criminal Police University Shenyang 110035 Liaoning Province China Department of Chemistry China Medical University School of Basic Medicine Shenyang 110001 Liaoning Province China North Railway Police Station Shenyang Public Security Bureau Shenyang 110013 Liaoning Province China Department of Police Dog Technology China Criminal Police University Shenyang 110035 Liaoning Province China

In this study, we sought to elucidate the process of DNA degradation in brain and dental pulp cells of mice, within postmortem 0-72 hours, by using the single cell gel electrophoresis assay and professional comet image analysis and processing techniques. The frequency of comet-like cells, the percentage of tail DNA, tail length, tail moment, Olive moment and tail area increased in tandem with increasing postmortem interval. In contrast, the head radius, the percentage of head DNA and head area showed a decreasing trend. Linear regression analysis revealed a high correlation between these parameters and the postmortem interval. The findings suggest that the single cell gel electrophoresis assay is a quick and sensitive method to detect DNA degradation in brain and dental pulp cells, providing an objective and accurate new way to estimate postmortem interval.

关键词： DNA degradation single cell gel electrophoresis postmortem interval brain dental pulp

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黑龙江森林冰雪文化旅游发展策略研究

林业勘查设计 2024年第3期53卷 69-74页

作者：孙莹关大伟黑龙江东方学院哈尔滨150066 黑龙江省林业和草原调查规划设计院哈尔滨150008

黑龙江拥有得天独厚的优质生态资源和冰雪资源,是全国最适合发展森林冰雪旅游的区域。黑龙江积极响应国家政策,发展森林冰雪文化旅游,不断丰富发展经济和保护生态之间的辩证关系,在实践中将“绿水青山就是金山银山,冰天雪地也是金山银... 详细信息

黑龙江拥有得天独厚的优质生态资源和冰雪资源,是全国最适合发展森林冰雪旅游的区域。黑龙江积极响应国家政策,发展森林冰雪文化旅游,不断丰富发展经济和保护生态之间的辩证关系,在实践中将“绿水青山就是金山银山,冰天雪地也是金山银山”化为生动的现实。分析黑龙江发展森林冰雪文化旅游的优势和必要性,立足黑龙江森林冰雪旅游面临的困境,提出黑龙江森林冰雪文化旅游发展策略。在面临国内外旅游市场的巨大竞争压力下,寻找黑龙江发展特色旅游之路,全力打造竞争力强、美誉度高的森林冰雪文化旅游品牌。

关键词：黑龙江森林资源冰雪文化旅游发展

Characterization of horseshoe vortex in a developing scour hole at a cylindrical bridge pier

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International Journal of Sediment Research 2019年第2期34卷 118-124页

作者： dawei guan Yee-Meng Chiew Maoxing Wei Shih-Chun Hsieh College of Harbour Coastal and Offshore EngineeringHohai University School of Civil and Environmental Engineering Nanyang Technological University

Since local scour at bridge piers in rivers and estuaries is a major cause of bridge failure,estimation of the maximum local scour depth is of great importance to hydraulic and coastal engineers.Although numerous studies that focus on scour-depth prediction have been done and published,understanding of the flow and turbulence characteristics of the horseshoe vortex that drives the scour mechanism in a developing scour hole still is immature.This study aims to quantify the detailed turbulent flow field in a developing clear-water scour hole at a circular pier using Particle Image Velocimetry(PIV).The distributions of velocity fields,turbulence intensities,and Reynolds shear stresses of the horseshoe vortex that form in front of the pier at different scour stages(t = 0,0.5,1,12,24,and 48 h)are presented in this paper.During scour development,the horseshoe vortex system was found to evolve from one initially small vortex to three vortices.The strength and size of the main vortex are found to increase with increasing scour depth.The regions of both the maximum turbulence intensity and Reynolds shear stress are found to form at a location upstream of the main vortex,where the large turbulent eddies have the highest possibility of occurrence.Results from this study not only provide new insight into the complex flow-sediment interaction at bridge piers,but also provide valuable experimental databases for advanced numerical simulations.

关键词： Sediment transport Scour Bridge pier PIV Horseshoe vortex Turbulence Scour hole

Experimental investigation on scour topography around high-rise structure foundations

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International Journal of Sediment Research 2021年第3期36卷 348-361页

作者： Yang Xiao Hao Jia dawei guan Dongfang Liang Saiyu Yuan Hongwu Tang State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Yangtze Institute for Conservation and Development Hohai University College of Harbour Coastal and Offshore Engineering Hohai University Department of Engineering University of Cambridge

The current study aims to investigate the characteristics of scour topography around High-Rise Structure Foundations(HRSFs) via physical modeling tests. Clear-water scour tests with a uniform non-cohesive bed are modeled under the action of unidirectional steady flows. Time variations of the erosion and deposition topography are measured. The results show that deposition downstream of the first dune behind the HRSF is not located on the centerline of the wake. The deposition pattern indicates that a long steady wake region exists behind the permeable foundation. The scour depth around an HRSF is much less than that around a monopile because of the structural permeability, which gives rise to the bleed flow and a weakened downflow and horseshoe vortex. Additionally, the asymmetry of the HRSF affects the scour rate but not the final equilibrium scour depth. The average scour slope decreases along the direction of the flow. On the contrary, the scour radial distance increases along the direction of the flow,with the average value changing from 1.36 Deto 2.35 De(where Deis the equivalent diameter of the foundation). Furthermore, the scour hole around the HRSF is serrated rather than smooth owing to the presence of multiple piles. Empirical formulae are suggested for estimating the evolution of scour depth and volume. These laboratory experiments provide reference information for relevant numerical modeling studies and can be applied to guide engineering designs in an ocean area.

关键词： High-rise structure foundation Scour Sediment transport Pile groups

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波浪条件下单桩冲刷大比尺试验研究

清华大学学报（自然科学版） 2024年第4期64卷 619-625页

作者：宫恩宇陈松贵陈鑫张凯豪管大为郑金海中国农业大学水利与土木工程学院北京100083 天津水运工程科学研究院天津300456 中国农业大学北京市供水管网系统安全与节能工程技术研究中心北京100083 佛山恒益热电有限公司佛山528100 河海大学海岸灾害及防护教育部重点实验室南京210024

发展海上风电技术在国家“双碳”战略中具有重要意义,单桩冲刷深度的预测是海上风电单桩冲刷研究的热点。受比尺效应的影响,传统的小比尺物理模型通常会导致冲刷深度预测公式的适用性受到限制。为此,该文在1∶13的大比尺物理模型中开展... 详细信息

发展海上风电技术在国家“双碳”战略中具有重要意义,单桩冲刷深度的预测是海上风电单桩冲刷研究的热点。受比尺效应的影响,传统的小比尺物理模型通常会导致冲刷深度预测公式的适用性受到限制。为此,该文在1∶13的大比尺物理模型中开展了局部冲刷试验,研究了不规则波条件下,KC(Keulegan-Carpenter)为4~9时,单桩周围的平衡冲刷深度和冲刷坑体积。研究发现,通过改进KC的计算方法,能够提高现有公式在不规则波条件下预测平衡冲刷深度的准确度。此外,提出了单桩周围局部平衡冲刷深度和冲刷坑体积的公式,为单桩防护施工时的抛石冗余量估算提供了简便的预测方法。

关键词：大比尺试验 KC(Keulegan-Carpenter) 平衡冲刷深度冲刷坑体积

Sleep Deprivation Selectively Down-Regulates Astrocytic 5-HT2B Receptors and Triggers Depressive-Like Behaviors via Stimulating P2X7 Receptors in Mice

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Neuroscience Bulletin 2020年第11期36卷 1259-1270页

作者： Maosheng Xia Zexiong Li Shuai Li Shanshan Liang Xiaowei Li Beina Chen Manman Zhang Chengyi Dong Alexei Verkhratsky dawei guan Baoman Li Practical Teaching Centre School of Forensic MedicineChina Medical UniversityShenyang 110122China Department of Orthopaedics The First HospitalChina Medical UniversityShenyang 110001China Faculty of Biology Medicine and HealthThe University of ManchesterManchester M139PLUK Department of Forensic Pathology School of Forensic MedicineChina Medical UniversityShenyang 110122China Department of Poison Analysis School of Forensic MedicineChina Medical UniversityShenyang 110122China

Chronic loss of sleep damages health and disturbs the quality of life.Long-lasting sleep deprivation(SD)as well as sleep abnormalities are substantial risk factors for major depressive disorder,although the underlying mechanisms are not clear.Here,we showed that chronic SD in mice promotes a gradual elevation of extracellular ATP,which activates astroglial P2X7 receptors(P2X7Rs).Activated P2X7Rs,in turn,selectively down-regulated the expression of 5-HT2B receptors(5-HT2BRs)in astrocytes.Stimulation of P2X7Rs induced by SD selectively suppressed the phosphorylation of AKT and FoxO3 a in astrocytes,but not in neurons.The overexpression of FoxO3a in astrocytes inhibited the expression of 5-HT2BRs.Down-regulation of 5-HT2BsRs instigated by SD suppressed the activation of STAT3 and relieved the inhibition of Ca2+-dependent phospholipase A2.This latter cascade promoted the release of arachidonic acid and prostaglandin E2.The depression-like behaviors induced by SD were alleviated in P2X7R-KO mice.Our study reveals the mechanism underlying chronic SD-induced depression-like behaviors and suggests 5-HT2BRs as a key target for exploring therapeutic strategies aimed at the depression evoked by sleep disorders.

关键词： Astrocyte Sleep deprivation P2X7 receptor 5-HT2B receptor FoxO3a

Guide to forensic pathology practice for death cases related to coronavirus disease 2019(COVID-19)(Trial draft)

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Forensic Sciences Research 2020年第1期5卷 1-7页

作者： Danmi Mao Nan Zhou Da Zheng Jiacheng Yue Qianhao Zhao Bin Luo dawei guan Yiwu Zhou Bingjie Hu Jianding Cheng(Translated) Faculty of Forensic Medicine Zhongshan School of MedicineSun Yat-Sen UniversityGuangzhouChina School of Forensic Medicine China Medical UniversityShenyangChina Department of Forensic Medicine Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina Department of Pathology Guangzhou Medical UniversityGuangzhouChina

Autopsy is of great significance for elucidating the pathological changes,pathogenesis and cause of death of Coronavirus Disease 2019(COVID-19)and can provide a theoretical basis for scientific and accurate prevention and control of its outbreak.Based on related laws and regulations,such as the Law of the People's Republic of China on Prevention and Control of Infectious Diseases,clinical manifestations and epidemiological characteristics of COVID-19 and guidelines on the prevention and control of this epidemic,combined with the practical work of forensic pathology examinations,we developed the Guide to Forensic Pathology Practice for Death Cases Related to Coronavirus Disease 2019(COVID-19)(Trial Draft).This guide describes the background investigation of the death cases,autopsy room requirements,personal pre-vention and protections,external examinations,autopsy practices and auxiliary examinations,and thus offers a reference for forensic and pathological examination institutions and staff.

关键词： Forensic sciences forensic pathology autopsy SARS-CoV-2 Coronavirus Disease 2019 (COVID-19) guide

Sudden cardiac death of Duchenne muscular dystrophy with NT-proBNP in pericardial fluid as a useful biomarker for diagnosis of the cause of death: a case report

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Forensic Sciences Research 2020年第2期5卷 165-169页

作者： Mengzhou Zhang Rui Zhao Tianshui Yu Jiaoyong Li Miao Zhang Shukun Jiang Linlin Wang Guohua Zhang Rubo Li Baoli Zhu dawei guan Department of Forensic Pathology China Medical University School of Forensic MedicineShenyangChina Remote Forensic Consultation Center Collaborative Innovation Center of Judicial CivilizationChina University of Political Science and LawBeijingChina

Duchenne muscular dystrophy(DMD)is one of the most common and severest muscular dystrophies.Although it can be a cause of death when associated with cardiac muscle and/or respiratory muscles,no cases of sudden deaths in the setting of undiagnosed DMD with cardiac involvement have been reported in the literatures.Previous studies showed that N-terminal-proBNP(NT-proBNP)was a robust laboratory biomarker to diagnose and monitor cardiac failure in clinical situations,suggesting that it may be used as an auxiliary indicator for diagnosis on left ventricular dysfunction in sudden cardiac deaths in forensic settings.Here,we reported a case of 29-year-old man who died suddenly.Autopsy revealed that muscles of the body were almost replaced by fatty and fibrotic tissues.The heart was enlarged with disarray and degeneration of cardiomyocytes in cardiac muscle.Total absence of dystrophin was detected by immunohistochemical staining,which confirmed DMD.Postmortem biochemical test of pericardial fluid revealed a high level of NT-proBNP,indicating dysfunction of the left ventricle before death.The cause of death was certified as an early dilated cardiomyopathy(DCM)/dysfunction of the left ventricle secondary to DMD,suggesting that sudden cardiac death with cardiac dysfunction could be identified by immunohistochemical method in combination with pericardial fluid NT-proBNP determination after systemic autopsy.

关键词： Forensic sciences forensic medicine NT-proBNP sudden cardiac death Duchenne muscular dystrophy left ventricular dysfunction