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Underground Space 2024年第1期14卷 197-218页

作者： yi Yang Xing-gao Li Han-yuan Li yi-dong Guo ying-ran Fang Key Laboratory of Urban Underground Engineering of the Education Ministry Beijing Jiaotong UniversityBeijing 100044China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

This paper proposed a two-way coupled computational fluid dynamics(CFD)and discrete element method(DEM)approach to analyze the evolution of clogging in slurry shield tunneling *** interactions between clay particles and slurry were considered by exchanging three interaction forces,including buoyancy force,pressure gradient force,and drag *** CFD-DEM coupling approach was first benchmarked by comparing cutterhead torque and total thrust with field monitored data of a practical slurry shield tunnel *** evolution process of the particle phase and the fluid phase over time was *** results indicated that fewer than 70%of the particles can be washed away in time by the circulating *** 9%of the particles adhered to the submerged wall,resulting in increased cutterhead torque and *** parametric analysis,the influence of the shield driving parameters on the clay clogging behavior is further *** time history of cutterhead torque or thrust can be used as a criterion for judging whether clogging has ***,a new assessment method of clogging risk and an optimization strategy of driving parameters were proposed,which were intended to provide some guidance for similar projects.

关键词： Slurry shield Clogging Driving parameter optimization Assessment method CFD-DEM

Study of Flow and Heat Transfer in an Ejector-Driven Swirl Anti-Icing Chamber

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Fluid Dynamics & Materials Processing 2024年第5期20卷 989-1014页

作者： yi Tu yuan Wu Yu Zeng Hunan University of Arts and Sciences Hunan Key Laboratory of Distributed Electric Propulsion Vehicle Control TechnologyChangde415000China Liaoning Provincial Key Laboratory of Aircraft Ice Protection AVIC Aerodynamics Research InstituteShenyang110034China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic *** Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annular chamber to heat the engine inlet lip surface and prevent *** study employs a validated Computational Fluid Dynamics(CFD)approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing ***,the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the *** research findings indicate that,within the considered flow range,reducing the nozzle specific areaφfrom 0.03061 to 0.01083 can enhance the ejection coefficient by over 60.7%.This enhancement increases the air circulating rate,thereby intensifying convective heat transfer within the SAI ***,the reduction inφalso leads to a significant increase in the required bleed air pressure and a higher entropy generation rate,indicating lower exergy *** nozzle angleθnotably affects the distribution of hot and cold spots on the lip surface of the SAI ***θfrom 0°to 20°reduces the maximum temperature difference on the anti-icing chamber surface by 60 K.

关键词： Swirl anti-icing heat transfer exergy efficiency hot and cold spot aircraft engine

Mathematical Model,Numerical Simulation and Convergence Analysis of a Semiconductor Device Problem with Heat and Magnetic Influences

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 302-319页

作者： Chang-feng LI yi-rang yuan Huai-ling SONG School of Economics Shandong UniversityJinan 250100China Institute of Mathematics Shandong UniversityJinan 250100China College of Mathematics and Econometrics Hunan UniversityChangsha 410082China

In this paper,the authors discuss a three-dimensional problem of the semiconductor device type involved its mathematical description,numerical simulation and theoretical *** important factors,heat and magnetic influences are *** mathematical model is formulated by four nonlinear partial differential equations(PDEs),determining four major physical *** influences of magnetic fields are supposed to be weak,and the strength is parallel to the *** elliptic equation is treated by a block-centered method,and the law of conservation is *** computational accuracy is improved one *** equations are convection-dominated,thus are approximated by upwind block-centered *** difference can eliminate numerical dispersion and nonphysical *** diffusion is approximated by the block-centered difference,while the convection term is treated by upwind ***,the unknowns and adjoint functions are computed at the same *** characters play important roles in numerical computations of conductor device *** the theories of priori analysis such as energy estimates,the principle of duality and mathematical inductions,an optimal estimates result is *** a composite numerical method is shown for solving this problem.

关键词： three-dimensional conductor device problem with heat and magnetic influences upwind blockcentered differences elemental conservation of mass numerical analysis

Intrinsic correlation between the generalized phase equilibrium condition and mechanical behaviors in hydrate-bearing sediments

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2822-2832页

作者： Jiazuo Zhou Changfu Wei Rongtao Yan yuan Zhou yi Dong Hubei Key Laboratory of Marine Geological Resources College of Marine Science and TechnologyChina University of GeosciencesWuhanChina State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhanChina Guangxi Key Laboratory of New Energy and Building Energy Saving College of Civil Engineering and ArchitectureGuilin University of TechnologyGuilinChina

The phase equilibrium and mechanical behaviors of natural gas hydrate-bearing sediment are essential for gas recovery from hydrate *** heating closed systems,the temperature-pressure path of hydrate-bearing sediment deviates from that of pure bulk hydrate,reflecting the porous media effect in phase equilibrium.A generalized phase equilibrium equation was established for hydrate-bearing sediments,which indicates that both capillary and osmotic pressures cause the phase equilibrium curve to shift leftward on the temperature-pressure *** contrast to bulk hydrate,hydrate-bearing sediment always contains a certain amount of unhydrated water,which keeps phase equilibrium with the hydrate within the hydrate stability *** changes in temperature and pressure,a portion of pore hydrate and unhydrated water may transform into each other,affecting the shear strength of hydrate-bearing sediment.A shear strength model is proposed to consider not only hydrate saturation but also the change in temperature and pressure of hydrate-bearing *** model is validated by experimental data with various hydrate saturation,temperature and pressure *** deformation induced by partial dissociation was studied through depressurization tests under constant effective *** reduction in gas pressure within the hydrate stability field indeed caused sediment *** dissociation-induced deformation can be reasonably estimated as the difference in volume between hydrate-bearing and hydrate-free sediments from the compression curves.

关键词： Hydrate-bearing sediment Generalized phase equilibrium Unhydrated water Partial dissociation Mechanical behavior

Simultaneously enhanced electrochemical performance and air stability of Ni-rich cathode with a modified washing process

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Rare Metals 2024年第1期43卷 87-97页

作者： Ben-Rui Hu ying-yi yuan Yu-Cheng Wang Xun-Hui Xiong School of Environment and Energy Guangdong Provincial Key Laboratory of Advanced Energy Storage MaterialsSouth China University of TechnologyGuangzhou 510640China

Water washing has been regarded as one of the most effective strategies to remove surface residual lithium of nickel-rich layered oxides for lithium-ion batteries(LIBs).However,the loss of lattice lithium during the water washing process deteriorates the electrochemical performances and air ***,washing the LiNi_(0.90)Co_(0.05)Al_(0.02)O_(2)(NCA) with ammonium dihydrogen phosphate(NH_(4)H_(2)PO_(4)) solution has been proposed to simultaneously enhance electrochemical performances and air stability,in which in-situ generated Li_(3)PO_(4) coating layer on surface of NCA can suppress the loss of lattice ***,as a fast ionic conductor,Li_(3)PO_(4) coating layer on NCA can prevent the direct contact with electrolyte/*** a result,the NH_(4)H_(2)PO_(4) solution washed NCA cathode can deliver a high capacity of131.9 mAh·g^(-1) at 10.0C rate as well as impressive cycle stability with a capacity retention of 83.1% after 100 cycles at 1.0C,much higher than those of water washed NCA(WS-NCA) *** exposed in air for 7 days,the NH_(4)H_(2)PO_(4) solution washed NCA electrode can more effectively maintain the structural integrity as well as the electrochemical performances than water-washed *** work provides a simple and effective approach to enhance the cycle stability and air stability of Nickel-rich cathode materials.

关键词： Layered Ni-rich cathode Residual lithium Li_(3)PO_(4)coating Rate performance Air stability

Evaluation on cutting performance of novel PDC cutter for pipe jacking machine

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Underground Space 2024年第1期14卷 34-52页

作者： Long-Chuan Deng yi-Xiang yuan Xiao-Zhao Li Qian-Wei Zhuang Chi Zhang yi-Wei Chen School of Earth Sciences and Engineering Nanjing UniversityNanjingJiangsu 210023China Shanghai Tunnel Engineering Co.Ltd. Shanghai 200232China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China

It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated *** previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this *** on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut *** peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel *** LS-DYNA is employed to investigate the cutting performance in *** simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel ***,the linear cutting platform is adopted to investigate the force ability and damage state of PDC *** is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse *** patterns occurred in both numerical and experimental results are generally ***,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 *** tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC *** is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.

关键词： PDC cutter RC Pipe jacking machine Linear cutting tests Damage and wear LS-DYNA

Different lymph node staging systems for predicting the prognosis of colorectal neuroendocrine neoplasms

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1745-1755页

作者： yuan-yi Zhang Yue-Wei Cai Xia Zhang Department of Pathology Zhaoqing Medical CollegeZhaoqing 526020Guangdong ProvinceChina Department of Emergency Zhaoqing Second People’s HospitalZhaoqing 526020Guangdong ProvinceChina Department of Pathology and Physiology Zhaoqing Medical CollegeZhaoqing 526020Guangdong ProvinceChina

BACKGROUND Colorectal neuroendocrine neoplasms(NENs)are a rare malignancy that primarily arises from the diffuse distribution of neuroendocrine cells in the colon and *** studies have pointed out that the status of lymph node may be used to predict the *** To investigate the predictive values of lymph node ratio(LNR),positive lymph node(PLN),and log odds of PLNs(LODDS)staging systems on the prognosis of colorectal NENs treated surgically,and compare their predictive *** This cohort study included 895 patients with colorectal NENs treated surgically from the Surveillance,Epidemiology,and End Results *** endpoint was mortality of patients with colorectal NENs treated surgically.X-tile software was utilized to identify most suitable thresholds for categorizing the LNR,PLN,and *** were selected in a random manner to form training and testing *** prognosis of surgically treating colorectal NENs was examined using multivariate cox analysis to assess the associations of LNR,PLN,and LODDS with the prognosis of colorectal NENs.C-index was used for assessing the predictive *** conducted a subgroup analysis to explore the different lymph node staging systems’predictive *** After adjusting all confounding factors,PLN,LNR and LODDS staging systems were linked with mortality in patients with colorectal NENs treated surgically(P<0.05).We found that LODDS staging had a higher prognostic value for patients with colorectal NENs treated surgically than PLN and LNR staging *** results were obtained in the different G staging subgroup ***,the area under the receiver operating characteristic curve values for LODDS staging system remained consistently higher than those of PLN or LNR,even at the 1-,2-,3-,4-,5-and 6-year follow-up *** LNR,PLN,and LODDS were found to significantly predict the prognosis of patients with colorectal NENs treated surgically.

关键词： Positive lymph node Lymph node ratio Log odds of positive lymph nodes Prognosis Colorectal neuroendocrine neoplasms

Controllable Construction of Vinyl Sulfones and β-Keto Selenosulfones via Selective Oxidative Sulfonylation of Alkenes

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Chinese Journal of Chemistry 2024年第12期42卷 1367-1372页

作者： Xiang Liu yuan Zhang yi Zheng Changfeng Huang Hua Cao School of Chemistry and Chemical Engineering Guangdong Pharmaceutical UniversityZhongshanGuangdong 528458China

Comprehensive Summary The selective oxidative sulfonylation of alkenes with selenium sulfonate depended on the reaction *** electrochemical C—H sulfonylation proceeded smoothly to afford(E)-vinyl sulfones with good selectivity in an undivided cell without external *** aerobic trifunctionalization of alkenes occurred in the presence of KI in the air,which providesβ-keto selenosulfones via the formation of C—O,C—S,and C—Se bonds in *** control experiments,a plausible mechanism is proposed to rationalize the experimental results.

关键词： Synthetic methods Alkenes Difunctionalization Selenylation Sulfonylation

A Heuristic Radiomics Feature Selection Method Based on Frequency Iteration and Multi-Supervised Training Mode

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Computers, Materials & Continua 2024年第5期79卷 2277-2293页

作者： Zhigao Zeng Aoting Tang Shengqiu yi Xinpan yuan Yanhui Zhu School of Computer Hunan University of TechnologyZhuzhou412007China Hunan Key Laboratory of Intelligent Information Perception and Processing Technology Zhuzhou412007China

Radiomics is a non-invasive method for extracting quantitative and higher-dimensional features from medical images for *** has received great attention due to its huge application prospects in recent *** can know that the number of features selected by the existing radiomics feature selectionmethods is basically about *** this paper,a heuristic feature selection method based on frequency iteration and multiple supervised training mode is *** on the combination between features,it decomposes all features layer by layer to select the optimal features for each layer,then fuses the optimal features to form a local optimal group layer by layer and iterates to the global optimal combination *** with the currentmethod with the best prediction performance in the three data sets,thismethod proposed in this paper can reduce the number of features fromabout ten to about three without losing classification accuracy and even significantly improving classification *** proposed method has better interpretability and generalization ability,which gives it great potential in the feature selection of radiomics.

关键词： Radiomics feature selection machine learning metaheuristic

Nature-inspired design of droplet-synthesized polymeric nanoelectrode for photoelectrochemical microRNA sensing within single cells

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Science Bulletin 2024年第2期69卷 159-162页

作者： Si-yuan Yu yi-Li Liu Zheng Li Dechen Jiang Jing-Juan Xu Hong-yuan Chen Wei-Wei Zhao State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Nanoelectrodes have been shown to be powerful tools for nanoscopic research on single entities,deepening the understanding of heterogeneity and stochastics for single molecules,nanoparticles and cells[1–3].However,despite their importance,current nanoelectrode preparations are highly restrained to flame/electrochemical etching,metal sputtering,electrochemical deposition,etc.[3],resulting in a limited range of materials(mainly gold,platinum and carbon)for potential-resolved detection of redox-active species(Table S1 online).The enrichment of preparation methods to introduce novel materials and mechanisms should prove significant for the development of nanoelectrodes.

关键词： electrode deepening restrained