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Rockfill material uncertainty inversion analysis of concrete-faced rockfill dams using stacking ensemble strategy and Jaya optimizer

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Water Science and Engineering 2023年第4期16卷 419-428页

作者： Qin Ke ming-chao li Qiu-bing Ren Wen-chao Zhao State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300350China Bei Fang Investigation Design&Research Co.LtdTianjin 300222China

Numerical simulation of concrete-faced rockfill dams(CFRDs)considering the spatial variability of rockfill has become a popular research topic in recent *** order to determine uncertain rockfill properties efficiently and reliably,this study developed an uncertainty inversion analysis method for rockfill material parameters using the stacking ensemble strategy and Jaya *** comprehensive implementation process of the proposed model was described with an illustrative CFRD ***,the surrogate model method using the stacking ensemble algorithm was used to conduct the Monte Carlo stochastic finite element calculations with reduced computational cost and improved ***,the Jaya algorithm was used to inversely calculate the combination of the coefficient of variation of rockfill material *** optimizer obtained higher accuracy and more significant uncertainty reduction than traditional ***,the developed model effectively identified the random parameters of rockfill *** study provided scientific references for uncertainty analysis of *** addition,the proposed method can be applied to other similar engineering structures.

关键词： CFRD Uncertainty inversion analysis Stochastic finite element Surrogate model Stacking ensemble Jaya algorithm

Seepage and stress analysis of anti-seepage structures constructed with different concrete materials in an RCC gravity dam

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Water Science and Engineering 2015年第4期8卷 326-334页

作者： ming-chao li Xin-yu Guo Jonathan Shi Ze-biao Zhu State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University College of Engineering Louisiana State University

This study used the finite element method （FEM） to analyze the stress field and seepage field of a roller-compacted concrete （RCC） dam, with an upstream impervious layer constructed with different types of concrete materials, including three-graded RCC, two-graded RCC, conven- tional vibrated concrete （CVC）, and grout-enriched vibrated RCC （GEVR）, corresponding to the design schemes S 1 through $4. It also evaluated the anti-seepage performance of the imperious layer in the four design schemes under the normal water level and flood-check level. Stress field analysis of a retaining section and discharge section shows that the maximum tensile stress occurs near the dam heel, the maximum compressive stress occurs near the dam toe, and the stress distributions in the four schemes can satisfy the stress control criteria. Seepage field analysis shows that the uplift pressure heads in schemes S3 and S4 descend rapidly in the anti-seepage region, and that the calculated results of daily seepage flow under the steady seepage condition in these two schemes are about 30%-50% lower than those in the other two schemes, demonstrating that CVC and GEVR show better anti-seepage performance. The results provide essential parameters such as the uplift pressure head and seelga^e flow for physical model tests and anti-seepage structure selection in RCC dams.

关键词： RCC gravity dam Concrete parition Impervious layer FEM Seepage field Stress field

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Petroleum Science 2024年第4期21卷 2383-2392页

作者： li-ming Zhao Cai-Ping Lu Yang liu chao-chao li School of Mines China University of Mining and Technology Henan Institute of Geophysical Space Information

The similarities and differences in inherent mechanism and characteristic frequency between the onedimensional(1D) poroelastic model and the layered White model were investigated. This investigation was conducted under the assumption that the rock was homogenous and isotropic at the mesoscopic scale. For the inherent mechanism, both models resulted from quasi-static flow in a slow P-wave diffusion mode, and the differences between them originated from saturated fluids and boundary conditions. On the other hand, for the characteristic frequencies of the models, the characteristic frequency of the 1D poroelastic model was first modified because the elastic constant and formula for calculating it were misused and then compared to that of the layered White model. Both of them moved towards higher frequencies with increasing permeability and decreasing viscosity and diffusion length. The differences between them were due to the diffusion length. The diffusion length for the 1D poroelastic model was determined by the sample length, whereas that for the layered White model was determined by the length of the representative elementary volume(REV). Subsequently, a numerical example was presented to demonstrate the similarities and differences between the models. Finally, published experimental data were interpreted using the 1D poroelastic model combined with the Cole-Cole *** prediction of the combined model was in good agreement with the experimental data, thereby validating the effectiveness of the 1D poroelastic model. Furthermore, the modified characteristic frequency in our study was much closer to the experimental data than the previous prediction, validating the effectiveness of our modification of the characteristic frequency of the 1D poroelastic model. The investigation provided insight into the internal relationship between wave-induced fluid flow(WIFF)models at macroscopic and mesoscopic scales and can aid in a better understanding of the elastic modulus d

关键词： 1D poroelastic model Layered White model Quasi-static flow Slow P-wave diffusion Characteristic frequency Diffusion length

Microstructure and property of laser additive manufactured alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si after aged at different temperatures

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Rare Metals 2024年第5期43卷 2275-2281页

作者： Guo-chao li Xu Cheng Hua-ming Wang National Engineering Laboratory of Additive Manufacturing for Large Metallic Components and Engineering Research Center of Ministry of Education on Laser Direct Manufacturing for Large Metallic Components School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar *** this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was *** results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' *** at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine *** increasing the aging temperature,the number of α_(s) decreases but with coarsened *** aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°*** changing size of α_(s) obviously influences the property of the *** fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.

关键词： α+βtitanium alloy Laser additive manufacturing Solid solution and aging treatment Microstructure Room temperature tensile property

Deformation coordination analysis of CC-RCC combined dam structures under dynamic loads

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Water Science and Engineering 2020年第2期13卷 162-170页

作者： Bo-wen Shi ming-chao li ling-guang Song Meng-xi Zhang Yang Shen State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300350China Department of Construction Management University of HoustonHoustonTX 77204USA

A combined dam structure using different concrete materials offers many practical *** are several real-world cases where largevolume heterogeneous concrete materials have been used *** the engineering design standpoint,it is crucial to understand the deformation coordination characteristics and mechanical properties of large-volume heterogeneous concrete,which affect dam safety and *** this study,a large dam facility was selected for a case study,and various design schemes of the combined dam structure were developed by changing the configurations of material zoning and material types for a given dam *** analysis of the damfoundation-reservoir system for six schemes was carried out under dynamic conditions,in which the concrete damaged plasticity(CDP)model,the Lagrangian finite element formulation,and a surface-to-surface contact model were *** evaluate the mechanical properties of zoning interfaces and coordination characteristics,the vertical distribution of the first principal stress at the longitudinal joint was used as the critical index of deformation coordination control,and the overall deformation and damage characteristics of the dam were also *** a comparative study of the design schemes,an optimal scheme of the combined dam structure was identified:large-volume roller-compacted concrete(RCC)is recommended for the dam body upstream of the longitudinal joint,and high-volume fly ash conventional concrete(CC)for the dam body downstream of the longitudinal *** study provides engineers with a reference basis for combined dam structure design.

关键词： Combined dam structure Deformation coordination CC-RCC Dynamic response Finite element simulation Concrete damaged plasticity(CDP)model

Synergistic effect of Zr and Mo on precipitation and high-temperature properties of Al-Si-Cu-Mg alloys

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China Foundry 2024年第1期21卷 71-81页

作者： chao Gao Bing-rong Zhang Yin-ming li Zhi-ming Wang Xiang-bin Meng Faculty of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Hebei Ounai Machinery Mould Co.Ltd. Xingtai 054500HebeiChina

This study focuses on finding a solution to the sharp decline in mechanical properties of Al-Si-Cu-Mg alloys due to rapid coarsening of traditional intermediate phases at high temperature.A new type of modified al oy,to be used in automobile engines at high temperatures,was prepared by adding Zr and Mo into Al-Si-Cu-Mg *** synergistic effects of Zr and Mo on the microstructure evolution and high-temperature mechanical properties were *** show that the addition of Zr and Mo generates a series of intermetallic phases dispersed in the *** can improve the strength of the alloy by hindering dislocation movement and crack *** addition,some nano-strengthened phases show coherent interfaces with the matrix and improve grain *** addition of Mo greatly improves the heat resistance of the *** extremely low diffusivity of Mo enables it to improve the thermal stability of the intermetallic phases,inhibit precipitation during aging,reduce the size of the precipitates,and improve the heat resistance of the alloy.

关键词： Al-Si-Cu-Mg alloy high-temperature properties Zr-Mo-rich intermetallics nano-strengthening phases

Thermodynamic geometry of the RN-Ad S black hole and non-local observables

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Communications in Theoretical Physics 2024年第2期76卷 137-144页

作者： chao Wang Bin Wu Zhen-ming Xu Wen-li Yang Institute of Physics Shaanxi University of TechnologyHanzhong 723000China School of Physics Northwest UniversityXi'an 710127China Institute of Modern Physics Northwest UniversityXi'an 710127China Shaanxi Key Laboratory for Theoretical Physics Frontiers Xi'an 710127China Peng Huanwu Center for Fundamental Theory Xi'an 710127China

This paper studies the thermodynamic geometry of the Reissner–Nordstr?m-anti-de Sitter(RN-AdS)black hole via detection of the non-local observables in the dual field theory,including the entanglement entropy and equal-time two-point correlation *** the dimensional analysis,we construct the principle of corresponding states of black hole *** a result,our findings can be applied to black holes with different Ad S *** this sense,the probe of the thermodynamic geometry of the RN-Ad S black hole though the non-local observables in dual field theory has been confirmed numerically.

关键词： black hole thermodynamic thermodynamic geometry phase transition non-local observables

CYCLOPEPTIDE FROM THE SEEDS OF ANNONA GLABRA

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Chinese Chemical Letters 1995年第1期6卷 39-40页

作者： chao ming li Ning Hua TAN Hui Lan ZHENG Xiao Jiang HAO Jun ZHOU Acad Sinica Kunming Inst Bot Lab Phytochem Kunming 650204 Peoples R China Acad Sinica Kunming Inst Bot Xishuangbanna Trop Bot Garden Mengla 666303 Peoples R China

A new cyclopeptide glabrin A has been isolated from the seeds of Annona glabra. Its structure was elucidated by 2D-NMR and FAB-MS.

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Predictive value of FSH, testicular volume, and histopathological findings for the sperm retrieval rate of microdissection TESE in nonobstructive azoospermia： a meta-analysis

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Asian Journal of Andrology 2018年第1期20卷 30-36页

作者： Hao li li-Ping Chen Jun Yang ming-chao li Rui-Bao Chen Ru-Zhu Lan Shao-Gang Wang Ji-Hong liu Tao Wang Department of Urology Tongji Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Institute of Urology Tongji Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China

We performed this meta-analysis to evaluate the predictive value of different parameters in the sperm retrieval rate （SRR） of microdissection testicular sperm extraction （TESE） in patients with nonobstructive azoospermia （NOA）. All relevant studies were searched in PubMed, Web of Science, EMBASE, Cochrane library, and EBSCO. We chose three parameters to perform the meta-analysis： follicle-stimulating hormone （FSH）, testicular volume, and testicular histopathological findings which included three patterns： hypospermatogenesis （HS）, maturation arrest （MA）, and Sertoli-cell-only syndrome （SCOS）. If there was a threshold effect, only the area under the summary receiver operating characteristic curve （AUSROC） was calculated. Otherwise, the pooled sensitivity, specificity, positive likelihood ratio （PLR）, negative likelihood ratio （NLR）, and the diagnostic odds ratio （DOR） were also calculated. Twenty-one articles were included in our study finally. There was a threshold effect among studies investigating FSH and SCOS. The AUSROCs of FSH, testicular volume, HS, MA, and SCOS were 0.6119, 0.6389, 0.6758, 0.5535, and 0.2763, respectively. The DORs of testicular volume, HS, and MA were 1.98, 16.49, and 1.26, respectively. The sensitivities of them were 0.80, 0.30, and 0.27, while the specificities of them were 0.35, 0.98, and 0.76, respectively. The PLRs of them were 1.49, 10.63, and 1.15, respectively. And NLRs were 0.73, 0.72, and 0.95, respectively. All the investigated factors in our study had limited predictive value. However, the histopathological findings were helpful to some extent. Most patients with HS could get sperm by microdissection TESE.

关键词： microdissection TESE nonobstructive azoospermia prediction sperm retrieval rate