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Multi-level coarse-grained discrete element method modeling of cylinder particle flow in a rotating drum

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Particuology 2024年第5期88卷 218-238页

作者： lei xu Xiukai Wu Shuai Wang Shiyi Bao Institute of Process Equipment and Control Engineering Zhejiang University of TechnologyHangzhou 310023China Engineering Research Center of Process Equipment and Remanufacturing Ministry of EducationZhejiang University of TechnologyHangzhou 310023China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

The coarse-grained discrete element method(DEM)is probably a feasible option for simulating an actual drum-type biomass boiler,which contains over 10 million cylinder particles.A multi-level study was conducted based on particle and coarse-grained level data to evaluate the adequacy of the coarse-grained approach in terms of geometrical characteristics,kinematic features,and dynamic properties.Two scaling laws for contact parameters were used and compared during the simulations.The results show that the coarse-grained approach can accurately predict the positions of the free surface and active-passive interface,the mixing index,and the orientation properties.Deviations in the velocity fields may occur due to the worse flowability of coarse-grained particles near the free surface.The efficiency is significantly improved by the coarse-grained model compared with the corresponding original case(the same DEM code without a coarse-grained model was used for the original simulations).

关键词： Coarse-grained method Discrete element method(DEM) Cylinder particle Rotating drum Granular flow

Recent applications of macrocycles in supramolecular catalysis

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Chinese Chemical Letters 2024年第4期35卷 132-141页

作者： Conghui Wang lei xu Zhenhua Jia Teck-Peng Loh College of Advanced Interdisciplinary Science and Technology Henan University of TechnologyZhengzhou 450001China Division of Chemistry and Biological Chemistry School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore 637371Singapore Institute of Advanced Synthesis School of Chemistry and Molecular Engineering Nanjing Tech UniversityNanjing 211816China

Numerous supramolecular macrocycles have been utilized for developing catalysts by exploiting their specific molecular recognition and ability to form inclusion complexes through noncovalent interactions. The cyclic structure and modified functional groups of these macrocycles can influence substrate and transition state stability, as well as reaction selectivity. The inner cavities of these macrocycles are particularly beneficial, as they enable substrates to adopt preorganized arrangements and serve as versatile platforms for highly efficient supramolecular catalytic systems. This minireview provides an overview of recent advancements in supramolecular catalysis using various macrocycles, such as crown ethers, cyclodextrins,calixarenes, pillararenes, cucurbiturils, and other novel macrocycles.

关键词： Supramolecular catalysis Macrocycle Host-guest interactions Confinement Selectivity

Rockburst criterion and evaluation method for potential rockburst pit depth considering excavation damage effect

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1649-1666页

作者： Jinhao Dai Fengqiang Gong lei xu Engineering Research Center of Safety and Protection of Explosion & Impact of Ministry of Education (ERCSPEIME) Southeast UniversityNanjing211189China School of Civil Engineering Southeast UniversityNanjing211189China

Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit depth.Taking two diversion tunnels of Jinping II hydropower station for example,the relationship between rockburst pit depth and excavation damage effect is first surveyed.The results indicate that the rockburst pit depth in tunnels with severe damage to rock masses is relatively large.Subsequently,the excavation-induced damage effect is characterized by disturbance factor D based on the Hoek-Brown criterion and wave velocity method.It is found that the EDZ could be further divided into a high-damage zone(HDZ)with D=1 and weak-damage zone(WDZ),and D decays from one to zero linearly.For this,a quantitative evaluation method for potential rockburst pit depth is established by presenting a three-element rockburst criterion considering rock strength,geostress and disturbance factor.The evaluation results obtained by this method match well with actual observations.In addition,the weakening of rock mass strength promotes the formation and expansion of potential rockburst pits.The potential rockburst pit depth is positively correlated with HDZ and WDZ depths,and the HDZ depth has a significant contribution to the potential rockburst pit depth.

关键词： Deep tunnel Rockburst Rockburst pit Excavation damage effect Hoek-Brown criterion

Subclinical paraganglioma of the retroperitoneum:A case report

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World Journal of Clinical Cases 2024年第15期12卷 2672-2677页

作者： Li-Min Kang Fa-Kun Yu Fu-Wei Zhang lei xu Department of Hepatobiliary and Pancreatic Surgery Puer People's HospitalPuer 665000Yunnan ProvinceChina

BACKGROUND Paraganglioma(PGL)located in the retroperitoneum presents challenges in diagnosis and treatment due to its hidden location,lack of specific symptoms in the early stages,and absence of distinctive manifestations on imaging.CASE SUMMARY A 56-year-old woman presented with a left upper abdominal mass discovered 1 wk ago during a physical examination.She did not have a history of smoking,alcohol consumption,or other harmful habits,no surgical procedures or infectious diseases,and had a 4-year history of hypertension.Upon admission,she did not exhibit fever,vomiting,or abdominal distension.Physical examination indicated mild percussion pain in the left upper abdomen,with no palpable enlargement of the liver or spleen.Laboratory tests and tumor markers showed no significant abnormalities.Enhanced computed tomography and magnetic resonance imaging of the upper abdomen revealed a cystic solid mass in the left epigastrium measuring approximately 6.5 cm×4.5 cm,with inhomogeneous enhancement in the arterial phase,closely associated with the lesser curvature of the stomach and the pancreas.The patient underwent laparoscopic resection of the retroperitoneal mass,which was successfully removed without tumor rupture.A 12-month postoperative follow-up period showed good recovery.CONCLUSION This case report details the successful laparoscopic resection of a retroperitoneal subclinical PGL,resulting in a good recovery observed at the 12-month follow-up.Interestingly,the patient also experienced unexpected cure of hypertensive disease.

关键词： Paraganglioma Retroperitoneal anatomy Subclinical Pheochromocytoma Laparoscopy Case report

Simultaneous removal of sulfur dioxide and nitrogen oxide from flue gas by phosphorus sludge:The performance and absorption mechanism

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Chinese Journal of Chemical Engineering 2024年第1期65卷 212-221页

作者： Yuanyuan Yin xujun Wang lei xu Binbin He Yunxiang Nie Yi Mei Faculty of Chemical Engineering Kunming University of Science and TechnologyKunming 650500China Yunnan Provincial Key Laboratory of Energy Saving in Phosphorus Chemical Engineering and New Phosphorus Materials Kunming 650500China The Higher Educational Key Laboratory for Phosphorus Chemical Engineering of Yunnan Province Kunming 650500China

Developing low-cost and green simultaneous desulfurization and denitrification technologies is of great significance for sulfur dioxide(SO_(2))and nitrogen oxide(NO_(x))emission control at low temperatures,especially for small and medium-sized coal-fired boilers and furnaces.Herein,phosphorus sludge,an industrial waste from the production process of yellow phosphorus,has been developed to simultaneously eliminate SO_(2)and NO_(x)from coal-fired flue gas.The key factors affecting the experimental results indicate that desulfurization and denitrification efficiency of over 95%can be achieved at a low temperature of 55℃.Further,the absorption mechanism was investigated by characterizing the solid and liquid phases of the phosphorus sludge during the absorption process.The efficient removal of SO_(2)is attributed to the abundance of iron(Fe^(3+))and manganese(Mn^(2+))in the absorbent.SO_(2)can be rapidly catalyzed and converted to SO_(4)^(2-)by them.The key to NOx removal is the oxidation of NO toward watersoluble high-valent nitrogen oxides by oxidizing reactive substances induced via yellow phosphorus,which are then absorbed by water and converted to NO_(3)^(-).Meanwhile,yellow phosphorus is oxidized to phosphoric acid(H_(3)PO_(4)).The spent absorption slurry can be reused through wet process phosphoric acid production,as it contains sulfuric acid(H_(2)SO_(4)),nitric acid(HNO_(3)),and H_(3)PO_(4).Accordingly,this is a technology with broad application prospects.

关键词： Absorption Oxidation Multiphase reaction Phosphorus sludge Yellow phosphorus Low temperature

Appendiceal intussusception complicated by adenocarcinoma of the cecum:A case report

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World Journal of Clinical Cases 2024年第8期12卷 1461-1466页

作者： Yu Long Yi-Ning Xiang Fei Huang lei xu Xiao-Yun Li Yun-Huan Zhen Department of Colorectal Surgery The Affiliated Hospital of Guizhou Medical UniversityGuiyang 550001Guzihou ProvinceChina Department of Colorectal Surgery Guizhou Medical UniversityGuiyang 550001Guizhou ProvinceChina Department of Pathology The Affiliated Hospital of Guizhou Medical UniversityGuiyang 550001Guizhou ProvinceChina

BACKGROUND Appendiceal intussusception is a pathological condition in which the appendix is inverted into the cecum,which may cause symptoms that resemble those of other gastrointestinal disorders and may induce intestinal obstruction.The rarity of this case presentation is the co-occurrence of appendiceal intussusception and cecal adenocarcinoma,a combination that to our knowledge has not previously been reported in the medical literature.This case provides new insights into the complexities of diagnosing and managing overlapping pathologies.CASE SUMMARY A 25-year-old woman presented with persistent periumbilical pain and bloody stools.An initial biopsy showed cecal cancer;however,subsequent colonoscopy and computed tomography findings raised the suspicion of appendiceal intussus-ception,which was later confirmed postoperatively.This unique case was charac-terized by a combination of intussusception and adenocarcinoma of the cecum.The intervention included a laparoscopic right hemicolectomy,which led to the histopathological diagnosis of mucinous adenocarcinoma with appendiceal intussusception.The patient recovered well postoperatively and was advised to initiate adjuvant chemotherapy.This case highlights not only the importance of considering appendiceal intussusception in the differential diagnosis,but also the possibility of appendicitis and the atypical presentation of neoplastic lesions.CONCLUSIONS Physicians should consider the possibility of appendiceal intussusception in cases of atypical appendicitis,particularly when associated with neoplastic presentation.

关键词： Appendiceal intussusception Appendicitis Cecal cancer Target signs Misdiagnosis Case report

Proactive Caching at the Wireless Edge:A Novel Predictive User Popularity-Aware Approach

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1997-2017页

作者： Yunye Wan Peng Chen Yunni Xia Yong Ma Dongge Zhu xu Wang Hui Liu Weiling Li Xianhua Niu lei xu Yumin Dong College of Computer Science Chongqing UniversityChongqing400044China School of Computer and Software Engineering Xihua UniversityChengdu610039China School of Computer and Information Engineering Jiangxi Normal UniversityNanchang330022China Electric Power Research Institute of State Grid Ningxia Electric Power Co. Ltd.Yinchuan750002China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing400030China School of Computer Science and Technology Beijing Institute of TechnologyBeijing100083China School of Computer Science and Technology Dongguan University of TechnologyDongguan523808China School of Emergency Management Xihua UniversityChengdu610039China College of Computer and Information Science Chongqing Normal UniversityChongqing401331China

Mobile Edge Computing(MEC)is a promising technology that provides on-demand computing and efficient storage services as close to end users as possible.In an MEC environment,servers are deployed closer to mobile terminals to exploit storage infrastructure,improve content delivery efficiency,and enhance user experience.However,due to the limited capacity of edge servers,it remains a significant challenge to meet the changing,time-varying,and customized needs for highly diversified content of users.Recently,techniques for caching content at the edge are becoming popular for addressing the above challenges.It is capable of filling the communication gap between the users and content providers while relieving pressure on remote cloud servers.However,existing static caching strategies are still inefficient in handling the dynamics of the time-varying popularity of content and meeting users’demands for highly diversified entity data.To address this challenge,we introduce a novel method for content caching over MEC,i.e.,PRIME.It synthesizes a content popularity prediction model,which takes users’stay time and their request traces as inputs,and a deep reinforcement learning model for yielding dynamic caching schedules.Experimental results demonstrate that PRIME,when tested upon the MovieLens 1M dataset for user request patterns and the Shanghai Telecom dataset for user mobility,outperforms its peers in terms of cache hit rates,transmission latency,and system cost.

关键词： Mobile edge computing content caching system average cost deep reinforcement learning collaborative mechanism

N:ZnO/MoS_(2)-heterostructured flexible synaptic devices enabling optoelectronic co-modulation for robust artificial visual systems

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Nano Research 2024年第3期17卷 1902-1912页

作者： lei xu Wenxiao Wang Yang Li Yonghui Lin Wenjing Yue Kai Qian Qinglei Guo Jeonghyun Kim Guozhen Shen School of Information Science and Engineering University of JinanJinan 250022China School of Microelectronics Shandong UniversityJinan 250101China Department of Electronic Convergence Engineering Kwangwoon UniversitySeoul 01897Republic of Korea School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China

With the merits of non-contact,highly efficient,and parallel computing,optoelectronic synaptic devices combining sensing and memory in a single unit are promising for constructing neuromorphic computing and artificial visual chip.Based on this,a N:ZnO/MoS_(2)-heterostructured flexible optoelectronic synaptic device is developed in this work,and its capability in mimicking the synaptic behaviors is systemically investigated under the electrical and light signals.Versatile synaptic functions,including synaptic plasticity,long-term/short-term memory,and learning-forgetting-relearning property,have been achieved in this synaptic device.Further,an artificial visual memory system integrating sense and memory is emulated with the device array,and the visual memory behavior can be regulated by varying the light parameters.Moreover,the optoelectronic co-modulation behavior is verified by applying mixed electric and light signals to the array.In detail,a transient recovery property is discovered when the electric signals are applied in synergy during the decay of the light response,of which property facilitates the development of robust artificial visual systems.Furthermore,by superimposing electrical signals during the light response process,a differentiated response of the array is achieved,which can be used as a proof of concept for the color perception of the artificial visual system.

关键词： flexible synaptic device synaptic plasticity optoelectronic synapse robust visual memory optoelectronic co-modulation artificial visual system

N-glycan biosignatures as a potential diagnostic biomarker for earlystage pancreatic cancer

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 659-669页

作者： Yan-Rong Wen Xia-Wen Lin Yu-Wen Zhou lei xu Jun-Li Zhang Cui-Ying Chen Jian He Department of Nuclear Medicine Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210008Jiangsu ProvinceChina Department of Research and Development Sysdiagno(Nanjing)Biotech Co.LtdNanjing 210008Jiangsu ProvinceChina

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)has a poor prognosis,with a 5-year survival rate of less than 10%,owing to its late-stage diagnosis.Early detection of pancreatic cancer(PC)can significantly increase survival rates.AIM To identify the serum biomarker signatures associated with early-stage PDAC by serum N-glycan analysis.METHODS An extensive patient cohort was used to determine a biomarker signature,in-cluding patients with PDAC that was well-defined at an early stage(stages I and II).The biomarker signature was derived from a case-control study using a case-cohort design consisting of 29 patients with stage I,22 with stage II,4 with stage III,16 with stage IV PDAC,and 88 controls.We used multiparametric analysis to identify early-stage PDAC N-glycan signatures and developed an N-glycan sig-nature-based diagnosis model called the“Glyco-model”.RESULTS The biomarker signature was created to discriminate samples derived from patients with PC from those of controls,with a receiver operating characteristic area under the curve of 0.86.In addition,the biomarker signature combined with cancer antigen 19-9 could discriminate patients with PDAC from controls,with a receiver operating characteristic area under the curve of 0.919.Glyco-model demonstrated favorable diagnostic performance in all stages of PC.The diagnostic sensitivity for stage I PDAC was 89.66%.Core Tip:This study employed a patient cohort to investigate the N-glycan signature of early-stage pancreatic cancer(PC).Serum N-glycans analysis was conducted to identify the serum biomarker signature associated with early-stage pancreatic ductal adenocarcinoma(PDAC),resulting in the identification of nine early-stage PDAC N-glycan signatures.Subsequently,utilizing these biosignatures,a diagnostic model named the“Glyco-model”was developed,demonstrating promising diagnostic performance across all stages of PC.The study revealed that the diagnostic sensitivity for stage I PDAC was determined to be 89.66%.Consequently,this diagnostic model exhibits potent

关键词： Glycomics N-glycans Biomarkers Pancreatic cancer Predictive modeling