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Effects of metallic microstructures on fatigue fracture of Q345 steel

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Journal of Iron and Steel Research(International) 2020年第6期27卷 702-709页

作者： Han-qing Liu Chun-ming wang Hong Zhang Zhi-yong Huang qing-yuan wang Qiang Chen School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065SichuanChina Failure Mechanics and Engineering Disaster Prevention and Mitigation Key Laboratory of Sichuan Province Sichuan UniversityChengdu 610065SichuanChina Department of Mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan School of Materials Science and Engineering Jiangxi University of Science and TechnologyGanzhou 341000JiangxiChina

Effects of high-frequency cyclic loading on the banded ferrite-pearlite steel were analyzed through crack initiation and propagation. Interfaces of ferrite and pearlite colony with a small angle deviation from the loading axis were verified to be the most potential sites to fabricate the microcracks caused by the high strain gradient. The initial crack extension inside ferrite grain was driven by shear stress in model II along the direction with a 45° angle to the loading axis. Banded pearlite colony and the high-angle grain boundaries were considered as the dominant factors that promote the fatigue resistance of the material through arousing crack deflection in short crack propagation range and crack branching in long crack propagation range to reduce the crack propagation driving force in the crack tip. P-S-N curves were used to quantify the dispersion of fatigue lifetimes and evaluate the effect of elevated volume content of pearlite colony on the fatigue performance of the material.

关键词： Ferrite-pearlite steel High-cycle fatigue Crack propagation Crack branching High-angle grain boundary P-S-N curve

Study on General Governing Equations of Computational Heat Transfer and Fluid Flow

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Communications in Computational Physics 2012年第10期12卷 1482-1494页

作者： wang Li Bo Yu Yi wang Xin-Ran wang qing-yuan wang Wen-Quan Tao Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of PetroleumBeijing102249People’s Republic of China Key Laboratory of Thermal Fluid Science and Engineering of MOE Xi’an Jiaotong UniversityXi’an710049People’s Republic of China

The governing equations for heat transfer and fluid flow are often formulated in a general formfor the simplification of discretization and programming,which has achieved great success in thermal science and engineering.Based on the analysis of the popular general form of governing equations,we found that energy conservation cannot be guaranteed when specific heat capacity is not constant,which may lead to unreliable results.A new concept of generalized density is put forward,based on which a new general form of governing equations is proposed to guarantee energy conservation.A number of calculation examples have been employed to verify validation and feasibility.

关键词： SIMPLE algorithm general form of governing equations conservation generalized variable fluid-solid coupling

Ultrasonic Fatigue Damage Behavior of 304L Austenitic Stainless Steel Based on Micro-plasticity and Heat Dissipation

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Journal of Iron and Steel Research(International) 2015年第7期22卷 638-644页

作者： Chao HE Ren-hui TIAN Yong-jie LIU Jiu-kai LI qing-yuan wang Key Laboratory of Energy Engineering Safety and Disaster Mechanics of Ministry of EducationCollege of Architecture and EnvironmentSichuan University

Very high cycle fatigue behavior （107 --109 cycles） of 304L austenitic stainless steel was studied with ultra- sonic fatigue testing system （20 kHz）. The characteristics of fatigue crack initiation and propagation were discussed based on the observation of surface plastic deformation and heat dissipation. It was found that micro-plasticity （slip markings） could be observed on the specimen surface even at very low stress amplitudes. The persistent slip mark- ings increased clearly along with a remarkable process of heat dissipation just before the fatigue failure. By detailed investigation using a scanning electron microscope and an infrared camera, slip markings appeared at the large grains where the fatigue crack initiation site was located. The surface temperature around the fatigue crack tip and the slip markings close to the fracture surface increased prominently with the propagation of fatigue crack. Finally, the cou- pling relationship among the fatigue crack propagation, appearance of surface slip markings and heat dissipation was analyzed for a better understanding of ultrasonic fatigue damage behavior.

关键词： very high cycle fatigue austenitic stainless steel micro-plasticity heat dissipation fatigue damage behavior

P-and SV-wave dispersion and attenuation in saturated microcracked porous rock with aligned penny-shaped fractures

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Petroleum Science 2024年第1期21卷 143-161页

作者： Sheng-qing Li Wen-Hao wang yuan-Da Su Jun-Xin Guo Xiao-Ming Tang School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Laoshan National Laboratory Qingdao 266071ShangdongChina Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology Southern University of Science and TechnologyShenzhen 518055GuangdongChina Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055GuangdongChina

P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned fractures.However,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic scale.Hence,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the fractures.Using Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and SV-waves.We then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy approximation.The results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave velocities.The coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV waves.Randomly oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV waves.Through a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model.

关键词： Aligned fractures P-and SV-wave Dispersion and attenuation Microcracked porous background FB-WIFF Elastic scattering Squirt flow

A pH/ROS dual-responsive system for effective chemoimmunotherapy against melanoma via remodeling tumor immune microenvironment

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2263-2280页

作者： Leilei wang Shanshan He Rong Liu yuan Xue yuan Quan Rongying Shi Xueying Yang qing Lin Xun Sun Zhirong Zhang Ling Zhang Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry West China School of PharmacySichuan UniversityChengdu 610041China Med-X Center for Materials College of Polymer Science and EngineeringSichuan UniversityChengdu 610065China

Chemotherapeutics can induce immunogenic cell death(ICD)in tumor cells,offering new possibilities for cancer therapy.However,the efficiency of the immune response generated is insufficient due to the inhibitory nature of the tumor microenvironment(TME).Here,we developed a pH/reactive oxygen species(ROS)dual-response system to enhance chemoimmunotherapy for melanoma.The system productively accumulated in tumors by specific binding of phenylboronic acid(PBA)to sialic acids(SA).The nanoparticles(NPs)rapidly swelled and released quercetin(QUE)and doxorubicin(DOX)upon the stimulation of tumor microenvironment(TME).The in vitro and in vivo results consistently demonstrated that the NPs improved anti-tumor efficacy and prolonged survival of mice,significantly enhancing the effects of the combination.Our study revealed DOX was an ICD inducer,stimulating immune responses and promoting maturation of dendritic cells(DCs).Additionally,QUE served as a TME regulator by inhibiting the cyclooxygenase-2(COX2)-prostaglandin E2(PGE2)axis,which influenced various immune cells,including increasing cytotoxic T cells(CLTs)infiltration,promoting M1 macrophage polarization,and reducing regulatory T cells(Tregs)infiltration.The combination synergistically facilitated chemoimmunotherapy efficacy by remodeling the immunosuppressive microenvironment.This work presents a promising strategy to increase anti-tumor efficiency of chemotherapeutic agents.

关键词： Quercetin Nanoparticle Responsiveness Chemoimmunotherapy Tumor immune microenvironment

Research on the prognostic value of adjusting intraperitoneal threedimensional quality evaluation mode in laparoscopic cholecystectomy patients

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World Journal of Gastrointestinal Surgery 2024年第4期16卷 1078-1086页

作者： yuan Zhou Zhan-qing Chen Operating Room Lianyungang Hospital of Traditional Chinese MedicineLianyungang 222000Jiangsu ProvinceChina Operating Room The Second People's Hospital of Lianyungang Affiliated to Kangda College of Nanjing Medical UniversityLianyungang 222000Jiangsu ProvinceChina

BACKGROUND Benign gallbladder diseases have become a high-prevalence condition not only in China but also worldwide.The main types of benign gallbladder diseases include gallbladder polyps,acute and chronic cholecystitis,and gallstones,with gallstones being the most common,accounting for over 70%of cases.Although the mortality rate of benign gallbladder diseases is low,they carry obvious potential risks.Studies have shown that an increased incidence of benign gallbladder diseases can increase the risk of cardiovascular diseases and gallbladder cancer,resulting in a substantial disease burden on patients and their families.AIM To assess the medical utility of the Configuration-Procedure-Consequence(CPC)three-dimensional quality evaluation model in modulating the prognosis of laparoscopic cholecystectomy patients.METHODS A total of 98 patients who underwent laparoscopic cholecystectomy in our hospital from February 2020 to January 2022 were selected as the subjects.According to the random number table method,they were divided into a study group and a control group,with 49 patients in each group.The control group received routine perioperative care,while the study group had the addition of the CPC three-dimensional quality evaluation.The postoperative recovery-related indicators(time to first flatus,time to oral intake,time to ambulation,hospital stay),stress indicators(cortisol and adrenaline levels),distinctions in anxiety and RESULTS The time to first flatus,time to oral intake,time to ambulation,and hospital stay of the study group patients were obviously lower than those of the control group patients,with statistical significance(P0.05).However,on the 3rd day after surgery,the cortisol and adrenaline levels,as well as SAS and SDS scores of the study gr

关键词： Configuration-Procedure-Consequence Three-dimensional quality evaluation Laparoscopic Cholecystectomy Recovery process Anxiety and depression Complications

Experimental study on the through-thickness properties of structural steel thick plate and its heat-affected zone at low temperatures

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2015年第3期16卷 217-228页

作者： yuan-qing wang Xiao-wei LIAO yuan-yuan ZHANG Yong-jiu SHI Key laboratory of Civil Engineering Safety and Durability of China Education Ministry Department of Civil Engineering Tsinghua University Beijing 100084 China

题目：低温条件下钢结构厚板及其热影响区的Z向性能试验研究　　目的：系统研究钢结构厚板在常温和低温条件下的Z向性能，并为其工程应用和评价指标的制定提供基础数据。　　方法：在常温和低温条件下，分别通过单轴静力拉伸试验、夏... 详细信息

题目：低温条件下钢结构厚板及其热影响区的Z向性能试验研究　　目的：系统研究钢结构厚板在常温和低温条件下的Z向性能，并为其工程应用和评价指标的制定提供基础数据。　　方法：在常温和低温条件下，分别通过单轴静力拉伸试验、夏比V型缺口冲击韧性试验和三点弯曲试验，研究钢结构厚板钢材及其热影响区的Z向和沿钢板轧制方向的力学性能指标、冲击韧性和断裂韧性随温度和钢板厚度变化的规律；并通过扫描电镜微观图像分析冲击试验和断裂试验的断口随温度和钢板厚度的变化。　　结论：1.钢结构厚板的Z向性能要低于沿钢板轧制方向的性能，包括屈服强度、抗拉强度、延性指标、冲击韧性和断裂韧性；2.焊接热输入会降低钢结构厚板热影响区母材 Z 向的力学和韧性指标；3.相比沿轧制方向的性能，钢结构厚板的Z向性能对温度和厚度的变化更敏感。

关键词：钢结构厚板 Z 向性能力学性能冲击韧性断裂韧性低温环境

Response enhancement of olfactory sensory neurons-based biosensors for odorant detection

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第4期10卷 285-290页

作者： Chun-sheng WU Pei-hua CHEN qing yuan Ping wang Biosensor National Special Laboratory MOE Key Laboratory of Biomedical Engineering Department of Biomedical Engineering Zhejiang University Hangzhou 310027 China

This paper presents a novel strategy for the response enhancement of olfactory sensory neurons (OSNs)-based biosensors by monitoring the enhancive responses of OSNs to odorants. An OSNs-based biosensor was developed on the basis of the light addressable potentiometric sensor (LAPS), in which rat OSNs were cultured on the surface of LAPS chip and served as sensing elements. LY294002, the specific inhibitor of phosphatidylinositol 3-kinase (PI3K), was used to enhance the responses of OSNs to odorants. The responses of OSNs to odorants with and without the treatment of LY294002 were recorded by LAPS. The results show that the enhancive effect of LY294002 was recorded efficiently by LAPS and the responses of this OSNs-LAPS hybrid biosensor were enhanced by LY294002 by about 1.5-fold. We conclude that this method can enhance the responses of OSNs-LAPS hybrid biosensors, which may provide a novel strategy for the bioelectrical signal monitor of OSNs in biosensors. It is also suggested that this strategy may be applicable to other kinds of OSNs-based biosensors for cellular activity detection, such as microelectrode array (MEA) and field effect transistor (FET).

关键词：生物传感器感觉神经元气味检测嗅觉光寻址电位传感器场效应晶体管信号监测活性检测

Molecular Mechanism of Polysaccharides Extracted from Chinese Medicine Targeting Gut Microbiota for Promoting Health

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Chinese Journal of Integrative Medicine 2024年第2期30卷 171-180页

作者： ZHAO Wen-xiao wang Tong ZHANG Ya-nan CHEN Qian wang yuan XING Yan-qing ZHENG Jun DUAN Chen-chen CHEN Lijun ZHAO Hai-jun wang Shijun School of Nursing Shandong University of Traditional Chinese MedicineShandong University of Traditional Chinese MedicineJi'nan(250355)China Shandong Co-innovation Center of Classic Traditional Chinese Medicine Formula Shandong University of Traditional Chinese MedicineJi'nan(250355)China College of Traditional Chinese Medicine Shandong University of Traditional Chinese MedicineJinan(250355)China

The accumulating evidence revealed that gut microbiota plays an important role in pathological process of disease including obesity,type 2 diabetes mellitus,heart failure,and non-alcoholic fatty liver disease.Polysaccharides extracted from Chinese medicine(CM)can not only alleviate pathological status but also promote health by anti-inflammatory,regulating immunity,lowering blood glucose and lipids,anti-cancer,and anti-oxidation.The alterations of gut microbiota composition and metabolism pathways are the potential mechanisms of CM polysaccharides treatment.In addition,they exert functions through gut-organ axis or play an indirect role by synergistic actions with other drugs or components mediated by gut microbiota.This review summarizes the molecular mechanisms of CM polysaccharides interacted with intestinal microbial inhabitants as potential prebiotics forpromoting health.

关键词： Chinese medicine polysaccharides gut microbiota short-chain fatty acids lipopolysaccharides gut-organaxis synergistic actions