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Random Forest-Based Fatigue Reliability-Based Design Optimization for Aeroengine Structures

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 665-684页

作者： Xue-qin li Lu-Kai Song School of Energy and Power Engineering Beihang UniversityBeijing100191China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityKowloonHong Kong999077China Research Institute of Aero-Engine Beihang UniversityBeijing100191China

Fatigue reliability-based design optimization of aeroengine structures involves multiple repeated calculations of reliability degree and large-scale calls of implicit high-nonlinearity limit state function,leading to the traditional direct Monte Claro and surrogate methods prone to unacceptable computing efficiency and *** this case,by fusing the random subspace strategy and weight allocation technology into bagging ensemble theory,a random forest(RF)model is presented to enhance the computing efficiency of reliability degree;moreover,by embedding the RF model into multilevel optimization model,an efficient RF-assisted fatigue reliability-based design optimization framework is *** the low-cycle fatigue reliability-based design optimization of aeroengine turbine disc as a case,the effectiveness of the presented framework is *** reliabilitybased design optimization results exhibit that the proposed framework holds high computing accuracy and computing *** current efforts shed a light on the theory/method development of reliability-based design optimization of complex engineering structures.

关键词： Random forest reliability-based design optimization ensemble learning machine learning

The Monsky Matrices and Non-congruent Numbers

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Algebra Colloquium 2024年第2期31卷 239-262页

作者： Guilin li Hourong qin Fei Xu Department of Mathematics Nanjing UniversityNanjing 210093China 不详

We give some sufficient conditions for non-congruent numbers in terms of the Monsky *** known criteria for non-congruent numbers can be viewed as special cases of our results.

关键词： congruent elliptic curve Selmer group Monsky matrix non-congruent number

Effect of tungsten carbide particles on microstructure and mechanical properties of Cu alloy composite bit matrix

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Journal of Iron and Steel Research International 2024年第2期31卷 519-530页

作者： Ding-qian Dong Feng-yuan He Xin-hui Chen hui li Kai-hua Shi hui-wen Xiong Xin Xiang li Zhang College of Mechanical Engineering Sichuan University of Science and EngineeringZigong643000SichuanChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083HunanChina Zigong Cemented Carbide Co. Ltd.Zigong643011SichuanChina Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Science and EngineeringZigong643000SichuanChina

Copper alloy composite bit matrix was prepared by pressureless vacuum infiltration,using at least one of the three kinds of tungsten carbide particles,for example,irregular cast tungsten carbide,monocrystalline tungsten carbide and sintered reduced tungsten carbide *** effects of powder particle morphology,particle size and mass fraction of tungsten carbide on the microstructure and mechanical properties of copper alloy composite were investigated by means of scanning electron microscopy,X-ray diffraction and abrasive wear test in *** results show that tungsten carbide morphology and particle size have obvious effects on the mechanical properties of copper alloy *** tungsten carbide partially dissolved in the copper alloy binding phase,and layers of Cu_(0.3)W_(0.5)Ni_(0.1)Mn_(0.1)C phase with a thickness of around 8–15μm were formed on the edge of the cast tungsten *** 45%irregular crushed fine cast tungsten carbide and 15%monocrystalline cast tungsten carbide were used as the skeleton,satisfactory comprehensive performance of the reinforced copper alloy composite bit matrix was obtained,with the bending strength,impact toughness and hardness reaching 1048 MPa,4.95 J/cm^(2) and 43.6 HRC,*** main wear mechanism was that the tungsten carbide particles firstly protruded from the friction surface after the copper alloy matrix was worn,and then peeled off from the matrix when further wear occurred.

关键词： Polycrystalline diamond compact Pressureless vacuum infiltration Copper alloy composite bit matrix Microstructure characterization Abrasive wear behavior

Application of carbon materials for Zn anode protection in aqueous Zn metal batteries

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Rare Metals 2024年第10期43卷 4807-4843页

作者： Cui-qin Chao Yan-Nan li Yan Zhao College of Energy Materials and Chemistry Inner Mongolia University School of Physical Science and Technology Inner Mongolia University

Aqueous Zn metal batteries (AZMBs) have gained widespread attention due to their high theoretica specific capacity,good safety,and low *** Zn anodes suffer from serious problems of dendrites and side reactions,which should be solved by modifying the Zn anode (Zn host,protective layer),electrolyte,and *** materials with structurally tunable and physicochemical stability properties have been widely used in the study of Zn anode protection and have also been reviewed in the past ***,review reports on carbon-based Zn anodes for Zn anode protection from new perspectives are still urgently ***,the timeliness of the review reports is very valuable for researchers to timely and accurately understand the dynamics of the research ***,this review firs reports the significance of AZMBs and summarizes the current main challenges that should be solved for practical ***,the ways to construct long-life Zn anodes using carbon materials from the perspectives of modified carbon materials with gradient properties (gradient zincophilicity,gradient electrical conductivity,and multigradient deposition) as protective layers/hosts to guide Zn ions toward bottom-up gradient Zn deposition are *** addition,the recent advances of carbon materials for electrolyte and separator modifications are ***,the remaining challenges and future perspectives of carbon materials in AZMBs Zn anode protection are briefly outlined.

关键词： Anode protection Aqueous Zn battery Carbon Gradient deposition

Oleanonic acid inhibits glioma growth by inactivating STAT3 via upregulating SIRT6 in nude mice

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Food Science and Human Wellness 2024年

作者： Jiancun Wang Yuanyuan Wang hui Gao qin Sun Wen li Neurosurgery Department of the First Affiliated Hospital of Soochow University Department of Neurosurgery， the Third Affiliated Hospital of Naval Medical University Department of anesthesiology， General Hospital Of Eastern Theater Command Department of Pharmacology， School of Medicine， Shaoxing University

Patients with glioma have a very high mortality rate， thus improving the poor prognosis of glioma has been the goal in the therapeutic field. Searching for more effective drugs for gliomas from natural compounds is a promising strategy. In this study， both oleanonic acid and oleanolic acid inhibited proliferation of glioma cells and reduced expression of cyclin D1 and E1， but the former has a lower IC50 than the latter. Oleanonic acid reduced the expression of p-STAT3 but not p-STAT1 and 5， and also reducing the expression of STAT3 in the nucleus and its transcriptional activity in glioma cells. Furthermore， knockdown of STAT3 expression inhibited proliferation and migration of glioma cells. Next， the expressions of the upstream regulators such as SIRT6 and p-JAK2 but not SIRT1， p-ERK1/2， p300 were increased by oleanonic acid. The overexpression of SIRT6 not only reduced the expression of p-STAT3 and its transcriptional activity but also inhibited the proliferation and migration of glioma cells. In addition， the effects that oleanonic acid reduced the expression of p-STAT3 and its transcriptional activity and inhibited the proliferation and migration were attenuated by the knockdown of SIRT6. Furthermore， oleanonic acid effectively suppressed glioma growth and extended survival in nude mice bearing intracerebral U87 xenografts， but not in nude mice bearing intracerebral SIRT6-knockdown U87 xenografts. In conclusion， oleanonic acid upregulates the expression of SIRT6 to inactivates STAT3 and then inhibits glioma growth.

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Advances in immunotherapy for hepatitis B virus associated hepatocellular carcinoma patients

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World Journal of Hepatology 2024年第10期16卷 1158-1168页

作者： Wei-Hua Cao Ya-qin Zhang Xin-Xin li Zi-Yu Zhang Ming-hui li Department of Hepatology Division 2 Beijing Ditan HospitalCapital Medical UniversityBeijing 100015China Department of Hepatology Division 2 Beijing Ditan HospitalCapital Medical UniversityPeking University Ditan Teaching HospitalBeijing 100015China

Hepatitis B virus(HBV)infection plays an important role in the occurrence and development of hepatocellular carcinoma(HCC),and the rate of HBV infection in liver cancer patients in China is as high as 92.05%.Due to long-term exposure to chronic antigens from the gut,the liver needs to maintain a certain level of immune tolerance,both to avoid severe inflammation caused by non-pathogenic antigens and to maintain the possibility of rapid and violent responses to infection and ***,HBV infection interacts with the tumor microenvironment(TME)through a highly complex and intertwined signaling pathway,which results in a special TME in *** to changes in the TME,tumor cells can evade immune surveillance by inhibiting tumor-specific T cell function through cytotoxic T-lymphocy-associated protein-4(CTLA-4)and programmed cell death 1(PD-1)/programmed cell death ligand 1(PD-L1).Interferons,as a class of immune factors with strong biological activity,can improve the TME of HBV-HCC through various *** recent years,the systematic treatment of HCC has gradually come out of the *** addition to the continuous emergence of new multi-target anti-vascular tyrosine kinase inhibitor drugs,immune checkpoint inhibitors have opened up a new avenue for the systematic treatment of *** present,immunotherapy based on PD-1/L1 inhibitors has gradually become a new direction of systematic treatment for HCC,and the disease charac-teristics of patients included in global clinical studies are different from those of Chinese ***,whether a group of HCC patients with HBV background and poor prognosis in China can also benefit from immunotherapy is an issue of wide *** review aims to elucidate the advances of immuno-therapy for HBV related HCC patients with regard to:(1)Immunotherapy based on interferons;(2)Immunotherapy based on PD-1/L1 inhibitors;(3)Immunotherapy based on CTLA4 inhibitors;(4)Adoptive cell transfer;(5)Combination immunotherapy str

关键词： Hepatitis B virus Hepatocellular carcinoma Immune checkpoint inhibitors Peginterferon alpha Systematic treatment

Measurement of acceleration and angular velocity of particles during a 3D silo discharge

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Particuology 2024年第9期92卷 61-71页

作者： Tongtong Mu Yiming li Quan Chen Ran li hui Yang College of Medical Instrument Shanghai University of Medicine and Health SciencesShanghai201318China School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China

Accurate measurement of the three-dimensional(3D)movement of discrete particles is crucial for comprehending complex granular rheology in *** this paper,the acceleration and angular velocity of particles in 3D silos are measured by using a spherical detector based on inertial technology and magnetic positioning *** acceleration of particles is the largest in the center of silos,which suggest that the resistance generated by friction and extrusion is the ***,the angular velocity distribution follows lognormal function except for particles near the *** correlation between acceleration and angular velocity is opposite in different flow *** reveals for the first time that the extent to which the resultant force on the particles affects their rotational motion is related to the flow *** results have practical significance for regulating the granular flow pattern and optimizing the structural design of silos.

关键词： Granularflow Silo Angular velocity Acceleration

Selective hydrodeoxygenation of guaiacol to cyclohexanol using activated hydrochar-supported Ru catalysts

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 13-22页

作者： Kaile li Shijie Yu qinghai li Yanguo Zhang hui Zhou Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO_(2) Utilization and Reduction TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore117585Singapore

lignin,an abundant aromatic polymer in nature,has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental *** hydrodeoxygenation of guaiacol,a lignin-derived monomer,can produce cyclohexanol,a nylon precursor,in a carbon-negative and environmentally friendly *** study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective *** selective cleavage of C_(ary)-O bonds was achieved under mild conditions(160°C,0.2 MPa H_(2),and 4 h),and alkali activation further improved the catalytic *** characterization methods revealedthat hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion.X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium,indicating the effective regulation of interaction between active sites and *** synergistic approach used in this study,involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol,indicated the comprehensive and sustainable utilization of biomass resources.

关键词： hydrochar guaiacol cyclohexanol activation full-component utilization

Anomalous response to creep deformation from dislocation density during electrically assisted creep aging

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Rare Metals 2024年第10期43卷 5268-5283页

作者： Chang Zhou li-Hua Zhan Chun-hui liu Ming-hui Huang College of Mechanical and Electrical Engineering Central South University light Alloys Research Institute State Key Laboratory of Precision Manufacturing for Extreme Service PerformanceCentral South University

Adding numerous dislocations into metallic materials before the forming stage significantly enhances their deformability. However, this beneficial effect of dislocation defects may not have a simple monotonic relationship with increased dislocation density during electroplastic deformation. This is due to the complex interactions among the drifting electrons, dislocations and solute atoms. This study explores the effect of diverse initial dislocation densities on creep deformation during electrically aided creep aging of an aluminum–lithium alloy. Surprisingly, we discovered a threshold value for the dislocation density that affects electroplastic creep, i.e., an enhanced effect from dislocations weakens when exceeding this density threshold(an anomalous response to creep). Microstructural data also reveal that such an anomalous response originates mainly from differences in various dislocation density-tailored configurations, which can influence the dislocation motions and precipitation kinetics of the strengthening T1precipitates under the same action of pulsed currents. This study provides important insights into the dislocation density-mediated electroplastic creep of an aluminum–lithium alloy.

关键词： Al–Cu–li alloy Creep aging Dislocation density Pulsed currents