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Construction technology for deep tunnels crossing superhigh-temperature fault zones with high water surges

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1267-1280页

作者： Yong ZHAO Tingyu ZHU li YU ming LU Sichuan–Xizang Railway Co. Ltd.Linzhi 860000China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610036China

The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and *** main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature control measures,and insufficient systematic *** this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A cooling strategy is proposed to offer technical support in achieving comprehensive cooling,overall as well as for each of the ***,a comprehensive geological survey explores the mechanism and exact location of the heat ***,grouting and centralized drainage measures are used to control the heat release of hot *** ventilation,ice chillers and other applicable measures are used to control the ambient ***,a monitoring and early warning system is established to prevent *** cooling strategy has been applied in the field with good results.

关键词： high geothermal tunnels cooling strategy comprehensive cooling measures safety and security

Development of CONTHAC-3D and hydrogen distribution analysis of HPR1000

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Nuclear Science and Techniques 2024年第2期35卷 210-221页

作者： Hui Wang Jing-Jing li Yuan Chang Gong-lin li ming Ding China Nuclear Power Engineering Co.LTD. Beijing 100084China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin 100049China

An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe ***-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the ***-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling *** validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment *** hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by ***,the hydrogen distribution in the HPR1000 containment during a severe accident was *** results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the *** amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is ***,we do not recommend installing all autocatalytic recombiners at high *** study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.

关键词： Hydrogen risk mitigation Pressurized water reactor HPR1000 Thermal hydraulic CONTHAC-3D

Preheating-assisted solid-state friction stir repair of Al-Mg-Si alloy plate at different rotational speeds

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 725-736页

作者： Hui Wang Yidi li ming Zhang Wei Gong Ruilin Lai Yunping li State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Research Institute of light Alloy Central South UniversityChangsha 410083China

Additive friction stir deposition(AFSD)is a novel structural repair and manufacturing technology has become a research hotspot at home and abroad in the past five *** this work,the microstructural evolution and mechanical performance of the Al-Mg-Si alloy plate repaired by the preheating-assisted AFSD process were *** evaluate the tool rotation speed and substrate preheating for repair quality,the AFSD technique was used to additively repair 5 mm depth blind holes on 6061 aluminum alloy *** results showed that preheat-assisted AFSD repair significantly improved joint bonding and joint strength compared to the control non-preheat substrate ***,increasing rotation speed was also beneficial to improve the metallurgical bonding of the interface and avoid volume *** preheating conditions,the UTS and elongation were positively correlated with rotation *** the process parameters of preheated substrate and tool rotation speed of 1000 r/min,defect-free specimens could be obtained accompanied by tensile fracture occurring in the substrate rather than the repaired *** UTS and elongation reached the maximum values of 164.2MPa and 13.4%,which are equivalent to 99.4%and 140%of the heated substrate,respectively.

关键词： additive friction stir deposition structural repair tool rotation speed Al alloy

TBAB hydrate formation and growth in a microdevice under static and dynamic conditions

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Petroleum Science 2024年第2期21卷 1396-1404页

作者： Xingxun li ming liu Qingping li Weixin Pang Guangjin Chen Changyu Sun State Key Laboratory of Heavy Oil Processing China University of Petroleum BeijingBeijing102249China State Key Laboratory of Natural Gas Hydrate CNOOC Research Institute Co.Ltd.Beijing100027China

The natural gas hydrate has become one of the most promising future green energy sources on the *** natural gas hydrates mostly exist in the sediments with porous structure, so a solid understanding of the hydrate formation and growth processes in the porous medium is of significance for the exploitation of natural gas hydrate. The micro-packed bed device is one of the efficient microfluidic devices in the engineering field, but it has been rarely used for the hydrate-based research. In this study, a transparent micro-packed bed device filled with glass beads was developed to mimic the porous condition of sediments, and used to in-situ visualize the hydrate formation and growth habits in the pore spaces under both static and dynamic conditions. For the static experiment, two types of hydrate growth patterns in porous medium were observed and identified in the micro-packed bed device, which were the graincoating growth and pore-filling growth. For the dynamic condition, the hydrate formation, growth,distribution habits and hydrate blockage phenomena in the pore spaces were in-situ visually *** impacts of flowrate and subcooling on the pressure variation of the micro-packed bed and the duration of the hydrate growth under dynamic flow condition in pores were in-situ monitored and analyzed. The higher flowrate could result in the faster hydrate growth and more severe blockage in pores, but the effect of subcooling condition might be less significant at the high flowrate.

关键词： Hydrate formation Hydrate growth Microdevice In-situ measurement

A Survey of Edge Caching:Key Issues and Challenges

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Tsinghua Science and Technology 2024年第3期29卷 818-842页

作者： Hanwen li mingtao Sun Fan xia xiaolong Xu Muhammad Bilal School of Computer Science Nanjing University of Information Science and TechnologyNanjing 210044China Shandong Provincial University Laboratory for Protected Horticulture Weifang University of Science and TechnologyWeifang 262700China Reading Academy Nanjing University of Information Science and TechnologyNanjing 210044China School of Software Nanjing University of Information Science and TechnologyNanjing 210044China Department of Computer Engineering Hankuk University of Foreign StudiesYongin-si 17035Republic of Korea

With the rapid development of mobile communication technology and intelligent applications,the quantity of mobile devices and data traffic in networks have been growing exponentially,which poses a great burden to networks and brings huge challenge to servicing user *** caching,which utilizes the storage and computation resources of the edge to bring resources closer to end users,is a promising way to relieve network burden and enhance user *** this paper,we aim to survey the edge caching techniques from a comprehensive and systematic *** first present an overview of edge caching,summarizing the three key issues regarding edge caching,i.e.,where,what,and how to cache,and then introducing several significant caching *** then carry out a detailed and in-depth elaboration on these three issues,which correspond to caching locations,caching objects,and caching strategies,*** particular,we innovate on the issue“what to cache”,interpreting it as the classification of the“caching objects”,which can be further classified into content cache,data cache,and service ***,we discuss several open issues and challenges of edge caching to inspire future investigations in this research area.

关键词： edge caching edge computing caching location caching object caching strategy 5G networkarchitecture Internet of Things(IoT)

Potentiation of the lateral habenula-ventral tegmental area pathway underlines the susceptibility to depression in mice with chronic pain

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Science China(life Sciences) 2024年第1期67卷 67-82页

作者： Chun-Kui Zhang Pan Wang Yuan-Yuan Ji Jian-Shuai Zhao Jun-xiang Gu xian-xia Yan Hong-Wei Fan ming-ming Zhang Yu Qiao xiao-Die liu Bao-Juan li ming-Hui Wang Hai-Long Dong Hao-Hong li Peng-Cheng Huang Yun-Qing li Wu-Gang Hou Jin-lian li Tao Chen Department of Anatomy and K.K.Leung Brain Research Centre Fourth Military Medical UniversityXi’an 710032China Beijing Institute of Basic Medical Sciences Beijing 100850China Key Laboratory of Ministry of Public Health for Forensic Science Xi’an Jiaotong UniversityXi’an 710061China Department of Anesthesiology Xijing HospitalFourth Military Medical UniversityXi’an 710032China Department of Neurosurgery the Second Affiliated Hospital of Xian Jiaotong UniversityXi’an 710004China School of Biomedical Engineering Fourth Military Medical UniversityXi’an 710032China Affiliated Mental Health Centre and Hangzhou Seventh People’s Hospital Zhejiang University School of MedicineHangzhou 310013China The MOE Frontier Research Center of Brain&Brain-machine Integration Zhejiang University School of Brain Science and Brain MedicineHangzhou 310058China Department of Neurology The First Affiliated Hospital of Nanchang UniversityNanchang 330006China Department of Anatomy School of MedicineNorthwest UniversityXi’an 710069China

Chronic pain often develops severe mood changes such as ***,how chronic pain leads to depression remains elusive and the mechanisms determining individuals’responses to depression are largely *** we found that depression-like behaviors could only be observed in 67.9%of mice with chronic neuropathic pain,leaving 32.1%of mice with depression *** determined that the spike discharges of the ventral tegmental area(VTA)-projecting lateral habenula(LHb)glutamatergic(Glu)neurons were sequentially increased in sham,resilient and susceptible mice,which consequently inhibited VTA dopaminergic(DA)neurons through a LHbGlu-VTAGABA-VTADA ***,the LHbGlu-VTADA excitatory inputs were dampened via GABAB receptors in a pre-synaptic *** of LHb-VTA pathway largely affected the development of depressive symptoms caused by chronic *** study thus identifies a pivotal role of the LHb-VTA pathway in coupling chronic pain with depression and highlights the activity-dependent contribution of LHbGlu-to-VTADA inhibition in depressive behavioral regulation.

关键词： chronic pain depression lateral habenula ventral tegmental area dopamine susceptibility

Flow Field Characteristics of Multi-Trophic Artificial Reef Based on Computation Fluid Dynamics

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Journal of Ocean University of China 2024年第2期23卷 317-327页

作者： HUANG Junlin li Jiao li Yan GONG Pihai GUAN Changtao xia Xu School of Engineering Ocean University of ChinaQingdao 266100China Yellow Sea Fisheries Research Institute Chinese Academy of Fishery SciencesKey Laboratory of Sustainable Development of Marine FisheriesMinistry of Agriculture and Rural AffairsQingdao Key Laboratory for Marine Fish Breeding and BiotechnologyQingdao 266071China Laboratory for Marine Fisheries Science and Food Production Processes Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266071China

On the basis of computational fluid dynamics,the flow field characteristics of multi-trophic artificial reefs,including the flow field distribution features of a single reef under three different velocities and the effect of spacing between reefs on flow scale and the flow state,were *** indicate upwelling,slow flow,and eddy around a single *** velocity,height,and volume of upwelling in front of a single reef were positively correlated with inflow *** length and volume of slow flow increased with the increase in inflow *** were present both inside and backward,and vorticity was positively correlated with inflow *** between reefs had a minor influence on the maximum velocity and height of *** the increase in space from 0.5 L to 1.5 L(L is the reef lehgth),the length of slow flow in the front and back of the combined reefs increased *** the space was 2.0 L,the length of the slow flow *** four different spaces,eddies were present inside and at the back of each *** maximum vorticity was negatively correlated with space from 0.5 L to 1.5 L,but under 2.0 L space,the maximum vorticity was close to the vorticity of a single reef under the same inflow velocity.

关键词： artificial reef flow field characteristics computation fluid dynamics multi-trophic structure

Mucosa color and size may indicate malignant transformation of chicken skin mucosa-positive colorectal neoplastic polyps

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 750-760页

作者： Ying-Jie Zhang Meng-xia Yuan Wu Wen Fan li Yi Jian Chuan-ming Zhang Ye Yang Feng-lin Chen Department of Digestive Diseases Chengdu Second People’s HospitalChengdu 610000Sichuan ProvinceChina Graduate School Chengdu Medical CollegeChengdu 610000Sichuan ProvinceChina

BACKGROUND lipid metabolism reprogramming is suspected to exist in pre-cancerous lesions,including colorectal *** colonoscopy frequently reveals chicken skin mucosa(CSM;white or yellow-white speckled mucosa)surrounding colo-rectal polyps,caused by macrophages engulfing and accumulating the lipids decomposed by colon cells or adjacent ***-positive colorectal polyps are associated with various diseases;however,their prognosis varies *** snare polypectomy is commonly used to resect lesions up to 10 to 15 mm in diameter without signs of submucosal invasion but is controversial for CSM-positive colorectal *** imaging is required to diagnose and treat CSM-positive colorectal *** This retrospective cohort study included 177 patients with CSM-positive colorectal polyps diagnosed using *** patient-related information was extracted from the Goldisc soft-clinic DICOM system or electronic medical record *** on the pathological results,patients were classified as non-neoplastic polyps(five juvenile polyps),neoplastic polyps,non-invasive high-grade neoplasia(NHGN),or submucosal invasive carcinoma(SM stage cancer).We analyzed and compared the clinical features,suspected risk factors for malignant transformation of neoplastic polyps,and early infiltration of sub-mucosal *** The diameters of NHGN and SM polyps were much smaller than those of neoplastic *** NHGN polyps had a deeper red mucosal *** logistic regression analyses,diameter and deeper red mucosal color were independent risk factors for malignant transformation of neoplastic *** 1 CSM was more common in high-grade intraepithelial neoplasia and SM;type 2 CSM was more common in neoplastic *** regression analyses revealed no significant differences in the malignant transformation of neoplastic polyps or early submucosal invasion of CSM-positive colorectal *** in the CSM mucosa surrounding neoplastic

关键词： Chicken skin mucosa Colorectal cancer Colorectal polyps Endoscopic resection Malignant transformation White light endoscopy

Beyond 1,4-addition of in-situ generated(aza-)quinone methides and indole imine methides

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Chinese Chemical Letters 2024年第7期35卷 35-53页

作者： Yan-li li Zhi-ming li Kai-Kai Wang xiao-Long He Medical College Xinxiang UniversityXinxiang 453000China School of Pharmacy Xinxiang UniversityXinxiang 453000China School of Food and Bioengineering Xihua UniversityChengdu 610039China

The conjugate addition of in-situ generated(aza-)quinone methides(QMs)and indole imine methides(IIMs)emerged as a powerful protocol to access densely functionalized benzenes and *** alcohols,aminobenzhydryl alcohols,and varied indolylmethanols served as most effective precursors for the in-situ generation of such reactive species under acid *** relevant propargylic alcohol has proven to be an elegant precursor to generate the propargylic-QMs and-IIMs via the acid promoted dehydration process,thus enabling diverse challenging remote activation to proceed conjugate1,6-and 1,***,the heteroarene has proven to be workable to transfer the LUMO of the p-QMs and 2-IIMs,thus inducing the remote nucleophilic dearomative *** conjugate additions of(aza-)p-QMs and varied IIMs has made significant contribution in the field of remote activation chemistry in past *** review summarizes the latest advances of the remote conjugate additions of the in-situ generated QMs and IIMs.

关键词： Conjugate addition QMs IIMs LUMO Remote activation Dearomative addition