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Rock fragmentation under different installation polar angles of TBM disc cutters

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Journal of Central South University 2017年第10期24卷 2306-2313页

作者： cheng yong-liang ZHONG Jue MEI yong-bing XIA Yi-min State Key Laboratory of High Performance Complex Manufacturing Central South University China Railway Construction Heavy Industry Co. Ltd.

The disc cutters of tunnel boring machine(TBM) are installed with different polar angles. This causes the cutting depth difference between adjacent disc cutters on the tunnel face. A rock-cutting model was established to study the rock fragmentation law between adjacent disc cutters with different polar angles based on particle flow code(PFC). The influence of polar angle of adjacent disc cutters on rock cracks and stresses under different cutter spacing and penetration was studied. Research shows that polar angle difference leads to the discontinuity of rock-fragmentation process by adjacent cutters. The effect of rock-fragmentation is influenced by the cutting depth difference between adjacent cutters. The effect of rock-fragmentation performed best, meanwhile large rock blocks were flaked when the difference of cutting depth is half of the penetration. Too large or small difference of the cutting depth will cause high specific energy consumption of rock fragmentation. The specific energy consumption is relatively small when the difference of cutting depth is half of the penetration.

关键词： tunnel boring machine disc cutter polar angle particle flow code rock fragmentation

Mendelian randomization analysis of causal relationship between cheese intake and diabetic retinopathy

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International Journal of Ophthalmology(English edition) 2024年第10期17卷 1905-1910页

作者： cheng-Ye Tang Dong-yong Tang Ying-Qin Yang Yu-Bing liang Hao liang Department of Ophthalmology the First Affiliated Hospital of Guangxi Medical UniversityNanning 530000Guangxi Zhuang Autonomous RegionChina Department of Ophthalmology the Affiliated Hospital of Guilin Medical UniversityGuilin 541001Guangxi Zhuang Autonomous RegionChina Department of Anesthesiology Guangxi Medical University Cancer HospitalNanning 530000Guangxi Zhuang Autonomous RegionChina

AIM:To assess whether there is a possible causal link between the intake of cheese and the risk of diabetic retinopathy(DR)utilizing a two-sample Mendelian randomization(MR)***:The research data were obtained from summary statistics of genome-wide association studies(GWAS).Genetic loci closely related to cheese intake were extracted as instrumental variables(IVs),and DR was the outcome *** data were extracted from individuals of European *** data of cheese intake consisted of 451486 samples with 9851867 single nucleotide polymorphisms(SNPs),while the DR data consisted of 206234 samples with 16380446 ***-one genetic loci closely related to cheese intake were selected as *** analysis was performed by inverse-variance weighted(IVW)method and MR-Egger regression *** causal relationship between cheese intake and DR was evaluated using odds ratios(ORs)and 95%confidence intervals(CIs).Egger-intercept test was used to test horizontal pleiotropy and sensitivity analysis was performed by leave-one-out ***:The P value of the IVW method was less than 0.05,indicating a significant negative correlation between cheese intake and ***-Egger regression showed that the intercept was 0.01 with a standard error of 0.022,and a P-value of 0.634,indicating no evidence of horizontal pleiotropy affecting the IVs related to the exposure ***,heterogeneity tests confirmed the absence of heterogeneity,and the“leave-one-out”sensitivity analysis demonstrated that the results were ***:Cheese intake is causally negatively correlated with the occurrence of DR,and cheese intake could reduce the risk of DR.

关键词： cheese intake diabetic retinopathy Mendelian randomization analysis

Orientational growth behavior and mechanism of delta(δ)phase precipitation in cold-rolled Inconel 718 alloy during heat treatment

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Journal of Iron and Steel Research International 2024年第1期31卷 264-274页

作者： Neng-yong Ye Guang-liang Zhang Tian-yue Huang Ming cheng Shi-hong Zhang Lei Wang School of Materials Science&Engineering Taizhou UniversityTaizhou318000ZhejiangChina Institute of Metal Research Chinese Academy of SciencesShenyang110016LiaoningChina

Due to the important role ofδphase's quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components,it is necessary to renew insights into the effect of cold deformation on theδphase precipitation,especially on the morphology ***,the nucleation and growth behavior ofδphase in cold-rolled Inconel 718 alloy during aging were *** results show that the precipitation rate and volume fraction ofδphase increase with increasing the cold rolling reduction from 10%to 50%.The volume fraction ofδphase reaches equilibrium after 5 h,remaining at 5.98%,6.52%,and 6.79%under different rolling reductions(10%,30%,and 50%),*** nucleation ofδphase mainly occurs on different sites(grain boundaries,new twin boundaries and old twin boundaries)under 10%rolling reduction,whileδphase mainly nucleates on the new grain boundaries of static recrystallization due to 50%rolling *** the growth ofδphase undergoes a process of alternate orientation growth from spherical(nucleation)→short rod(longitudinal orientation growth)→short rod(radial orientation growth)→dynamic *** 10%rolling reduction,δphase tends to grow into the matrix,while under 50%rolling reduction,the orientation grows faster and is easily affected by the grain boundary curvature.

关键词： Inconel 718 alloy Cold rolling δphase Orientation growth Morphology evolution

Thermoelectric transport properties of p-type Bi_(2)Se_(3)-Sb_(2)Se_(3)-In_(2)Se_(3) high entropy compounds

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Rare Metals 2024年第7期43卷 3415-3421页

作者： Feng Jiang cheng-liang Xia yong-Bin Zhu Jun Li Yue Chen Wei-Shu Liu Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

The introduction of entropy concept into thermoelectric materials recently has attracted broad ***,we showed the phase diagram of the ternary systems of Bi_(2)Se_(3)-Sb_(2)Se_(3)-In_(2)Se_(3).Among the high entropy compounds (HECs),we have identified an intrinsic p-type region near our previously reported Bi_(0.8)Sb_(0.8)In_(0.4)Se_(3) in the phase diagram.

关键词： entropy (3) compounds

The higher-order topological pumping explored in the 2D acoustic crystal

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 127-133页

作者： Yanqiu Wang Bin liang Jianchun cheng Key Laboratory of Modern Acoustics Ministry of EducationInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

The topological pumping has been instrumental in advancing our understanding of topological phase transitions in various physical systems,which can be extended to uncover intriguing higher-order topological phases in the lower-dimensional ***,we propose a theoretical exploration of topological dipole pumping on an acoustic square superlattice by cyclically modulating intracell couplings,which shares the topological nature of an extended three-dimensional system with chiral hinge *** the multipole chiral numbers,we characterize the higher-order topological phases that arise during the *** evolution of topological phase transitions is verified by numerical simulations and shows corner states are transferred across the *** findings can inspire the construction of chiral hinge states in artificial crystals,opening up new possibilities for the design of devices allowing the unidirectional propagation of sound.

关键词： topological phases of matter Thouless pumping acoustic metamaterial

A compact route for efficient production of high-purity β-Ga2O3 powder

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Rare Metals 2024年第9期43卷 4573-4584页

作者： Xiao-Wei Zhou Gao-Jie Chen liang Xu Zhi-Jun Shao cheng Yang yong-Pan Tian Zhuo Zhao School of Metallurgical Engineering Anhui University of Technology Low-Carbon Research Institute Anhui University of Technology

The present study has proposed a compact process for the production of high-purity β-Ga2O3powder by simply using gallium metal and water as the raw materials. The process basically consists of two essential steps including hydrothermal synthesis of Ga OOH and calcination of Ga OOH for the production of the target product of β-Ga2O3. Thermodynamic evaluation and systematic experiments were conducted for process parameter optimization. X-ray diffractometer（XRD）, scanning electron microscopy（SEM）, thermogravimetryDdifferential scanning calorimetry（TG-DSC） and X-ray photoelectron spectroscopy（XPS） were utilized to clarify the reaction mechanisms of the hydrothermal synthesis and transformation of Ga OOH to β-Ga2O3by calcination. Chemical analysis of the final product of β-Ga2O3obtained under the optimal conditions was carried out with inductively coupled plasma mass spectrometry（ICP-MS）, and the results showed that the contents of the representative impurities such as Ni, Cu, In, Mn, Co, Zn and Cr are obviously lower than the requirement of 5N β-Ga2O3standard, exhibiting excellent application prospect of the proposed process to produce high-purity β-Ga2O3.

关键词： Calcination Hydrothermal synthesis Purity Reaction mechanism β-Ga2O3

A Geometric Based Connection between Fractional Calculus and Fractal Functions

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Acta Mathematica Sinica,English Series 2024年第2期40卷 537-567页

作者： yong Shun liang Wei Yi SU School of Mathematics and Statistic Nanjing University of Science and TechnologyNanjing 210094P.R.China Department of Mathematics Nanjing UniversityNanjing 210023P.R.China

Establishing the accurate relationship between fractional calculus and fractals is an important research content of fractional calculus *** the present paper,we investigate the relationship between fractional calculus and fractal functions,based only on fractal dimension *** dimension of the Riemann-Liouville fractional integral of continuous functions seems no more than fractal dimension of functions *** fractal dimension of the Riemann-Liouville fractional differential of continuous functions seems no less than fractal dimension of functions themselves when they *** further discussion,fractal dimension of the Riemann-Liouville fractional integral is at least linearly decreasing and fractal dimension of the Riemann-Liouville fractional differential is at most linearly increasing for the Holder continuous *** about other fractional calculus,such as the Weyl-Marchaud fractional derivative and the Weyl fractional integral has also been given *** work is helpful to reveal the mechanism of fractional calculus on continuous *** the same time,it provides some theoretical basis for the rationality of the definition of fractional *** is also helpful to reveal and explain the internal relationship between fractional calculus and fractals from the perspective of geometry.

关键词： Fractional calculus fractal functions fractal dimension fractional calculus equation relationship

Optimal design of structural parameters for shield cutterhead based on fuzzy mathematics and multi-objective genetic algorithm

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Journal of Central South University 2015年第3期22卷 937-945页

作者：夏毅敏唐露暨智勇程永亮卞章括 State Key Laboratory of High Performance and Complex Manufacturing(Central South University) China Railway Construction Heavy Industry Co. Ltd.

In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.

关键词： shield tunneling machine cutterhead structural parameters fuzzy mathematics finite element optimization

Long-term operation optimization of circulating cooling water systems under fouling conditions

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Chinese Journal of Chemical Engineering 2024年第1期65卷 255-267页

作者： Jiarui liang yong Tian Shutong Yang yong Wang Ruiqi Yin Yufei Wang School of Chemical Engineering and Environment China University of PetroleumBeijing102249China CHN Energy Xinjiang Chemical Co. LTDUrumqi830092China College of Mechanical and Transportation Engineering China University of PetroleumBeijing 102249China

Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's ***,the operation optimization of CCWS often prioritizes short-term flow velocity optimization for minimizing power consumption,without considering ***,low flow velocity promotes ***,it's crucial to balance fouling and energy/water conservation for optimal CCWS long-term *** study proposes a mixed-integer nonlinear programming(MINLP)model to achieve this *** model considers fouling in the pipeline,dynamic concentration cycle,and variable frequency drive to optimize the synergy between heat transfer,pressure drop,and *** optimizing the concentration cycle of the CCWS,water conservation and fouling control can be *** model can obtain the optimal operating parameters for different operation intervals,including the number of pumps,frequency,and valve local resistance *** experiments on cycle and environmental temperature reveal that as the cycle increases,the marginal benefits of energy/water conservation *** periods with minimal impact on fouling rate,energy/water conservation can be achieved by increasing the cycle while maintaining a low fouling ***,the proposed model has significant energy/water saving effects and can comprehensively optimize the CCWS through its incorporation of fouling and cycle optimization.

关键词： Computer simulation Circulating water system Fouling Concentration cycle Optimization Variable frequency drive