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Finite element modeling of consolidation process of Si C fiber-reinforced titanium matrix composites via matrix-coated fiber method

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Rare Metals 2015年第12期34卷 844-850页

作者： Xiang-Hong Xu yan-qing yang Xian Luo Lin Qin Ju-Hong Lou qing Sun Shazhou Polytechnic Institute of Technology State Key Laboratory of Solidification Processing Northwestern Polytechnical University

The consolidation process of SiCf/Ti-6Al-4V composites by matrix-coated fiber (MCF) method via hot pressing was investigated using finite element modeling (FEM). By analyzing the elastic–plastic contact deformation of the representative aligned coated fibers, the consolidation maps delineating the time–temperature–pressure relationship for full densification were constructed. Both the flow coefficient and the contact area coefficient used to describe the contact deformation were calculated according to the model. In addition, the effect of fiber content on matrix stress distribution was analyzed. The results show that fiber content is a significant factor that influences the densification process. Higher fiber content will lower the consolidation rate.

关键词： Titanium matrix composites Consolidation Finite element modeling Matrix-coated fiber

Nano-Twinning and Martensitic Transformation Behaviors in 316L Austenitic Stainless Steel During Large Tensile Deformation

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Acta Metallurgica Sinica(English Letters) 2023年第5期36卷 758-770页

作者： Jin-Wang Liu Xian Luo Bin Huang yan-qing yang Wen-Jie Lu Xiao-Wei Yi Hong Wang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China

The evolutions of nano-twins and martensitic transformation in 316L austenitic stainless steel during large tensile deformation were studied by electron backscatter diffraction(EBSD)technology and transmission electron microscopy(TEM)in *** results show that due to the low stacking fault energy of the steel,phase transformation induced plasticity(TRIP)and twinning induced plasticity(TWIP)coexist during the tensile *** deformation firstly induces the formation of deformation twins,and dislocation pile-up is caused by the reduction of the dislocation mean free path(MFP)or grain refinement due to the twin boundaries,which further induces the martensitic *** the increase of tensile deformation,a large number of nano-twins andα’-martensite appear,and the width of nano-twins decreases gradually,meanwhile the frequency of the intersecting deformation twins *** martensitic transformation can be divided into two types:γ-austenite→α’-martensite andγ-austenite→ε-martensite.α’-martensite is mainly distributed near the twin boundaries,especially at the intersection of twins,whileε-martensite and stacking faults exist in the form of transition products between the twins and the matrix.

关键词： Austenitic stainless steel Intersecting-deformation twins Martensitic transformation High resolution transmission electron microscopy(HRTEM) Deformation mechanism

In Situ HRTEM Observation of Electron-Irradiation-Induced Amorphization and Dissolution of the E(Al_(18)Cr_2Mg_3) Phase in 7475 Al Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 147-151页

作者： Mao-Hua Li yan-qing yang Bin Huang Xian Luo Wei Zhang yan-Xia Chen Ming Han Ji-Gang Ru State Key Laboratory of Solidification Processing Northwestern Polytechnical University Beijing Institute of Aeronautical Materials

Electron irradiation effects on phase stability of the E （Al18Cr2Mg3） phase have been investigated by high- angle annular dark-field scanning transmission electron microscopy and high-resolution transmission electron microscopy （HRTEM）. The in situ HRTEM observations show that the Ala8Cr2Mg3 particles with different thickness undergo amorphization and dissolution under 300 keV electron irradiation at 25 ℃. The results indicate that the intermetallic compound Al18Cr2Mg3 is unstable under electron irradiation, and structural changes mainly depend on the thickness of particles. Amorphization in the thick particles is caused by a combination of chemical disordering and an increase in point defect concentration. Dissolution after amorphization in the thin particles is attributed to the diffusion of point defect towards the Al matrix.

关键词： Intermetallic compound Al18Cr2Mg3 Irradiation effects Amorphization Dissolution

Risk factors for progression to acute-on-chronic liver failure during severe acute exacerbation of chronic hepatitis B virus infection

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World Journal of Gastroenterology 2019年第19期25卷 2327-2337页

作者： Ling Yuan Bai-Mei Zeng Lu-Lu Liu Yi Ren yan-qing yang Jun Chu Ying Li Fang-Wan yang Yi-Huai He Shi-De Lin Department of Infectious Diseases Affiliated Hospital of Zunyi Medical University Department of Gastroenterology Jiangsu Province Hospital Pukou Branch Department of Respiratory Medicine the Fifth People’s Hospital of Chongqing

BACKGROUND Acute exacerbation in patients with chronic hepatitis B virus(HBV) infection results in different severities of liver injury. The risk factors related to progression to hepatic decompensation(HD) and acute-on-chronic liver failure(ACLF) in patients with severe acute exacerbation(SAE) of chronic HBV infection remain *** To identify risk factors related to progression to HD and ACLF in compensated patients with SAE of chronic HBV *** The baseline characteristics of 164 patients with SAE of chronic HBV infection were retrospectively reviewed. Independent risk factors associated with progression to HD and ACLF were identified. The predictive values of our previously established prediction model in patients with acute exacerbation(AE model) and the model for end-stage liver disease(MELD) score in predicting the development of ACLF were *** Among 164 patients with SAE, 83(50.6%) had compensated liver cirrhosis(LC),43 had progression to HD without ACLF, and 29 had progression to ACLF within 28 d after admission. Independent risk factors associated with progression to HD were LC and low alanine aminotransferase. Independent risk factors for progression to ACLF were LC, high MELD score, high aspartate aminotransferase(AST) levels, and low prothrombin activity(PTA). The area under the receiver operating characteristic of the AE model [0.844, 95%confidence interval(CI): 0.779-0.896] was significantly higher than that of MELD score(0.690, 95%CI: 0.613-0.760, P < 0.05) in predicting the development of *** In patients with SAE of chronic HBV infection, LC is an independent risk factor for progression to both HD and ACLF. High MELD score, high AST, and low PTA are associated with progression to ACLF. The AE model is a better predictor of ACLF development in patients with SAE than MELD score.

关键词： Acute-on-chronic liver failure Chronic hepatitis B Hepatic decompensation Liver cirrhosis Risk factors Severe acute exacerbation

Deformed microstructure and texture of Ti6Al4V alloy

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Transactions of Nonferrous Metals Society of China 2014年第10期24卷 3103-3110页

作者：杨柳青杨延清西北工业大学材料学院凝固技术国家重点实验室西安710072

Microstructure and texture evolution during hot compression of Ti6Al4 V alloy with an initial equiaxed microstructure were studied in the temperature range of 850-930 °C, strain rate range of 0.01-1 s-1 and engineering compressive strain of 70%. The results indicate that when temperature is below 900 °C and strain rate is higher than 0.1 s-1, the microstructure is mainly composed of elongated α grains. While deforming at higher temperatures and lower strain rates, dynamic recrystallization takes place. Electron back scattered diffraction（EBSD） result shows that during dynamic recrystallization, subgrain boundaries absorb dislocations and the recrystallized grains with high angle grain boundary form. At 930 °C dynamic recrystallization has basically completed, and needlelike α phase forms after water quenching. Pole figure analysis indicates that compared with the initial specimen, textures below 930 °C are weaker, while at 930 °C they are stronger.

关键词： Ti6Al4V alloy hot compression dynamic recrystallization EBSD texture

^(125)I-labeled anti-b FGF monoclonal antibody inhibits growth of hepatocellular carcinoma

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World Journal of Gastroenterology 2016年第21期22卷 5033-5041页

作者： Peng-Hui Hu Lan-Hong Pan Patrick Ting-Yat Wong Wen-Hui Chen yan-qing yang Hong Wang Jun-Jian Xiang Meng Xu Department of Oncology the First Affiliated Hospital of Jinan University Department of Endocrinology and Metabolism The First Affiliated Hospital of Jinan University Guangdong Province Key Laboratory of Molecular Immunology and Antibody Engineering Jinan University

AIM: To investigate the inhibitory efficacy of 125I-labeled anti-basic fibroblast growth factor (bFGF) monoclonal antibody (mAb) in hepatocellular carcinoma (HCC).METHODS: bFGF mAb was prepared by using the 1G9B9 hybridoma cell line with hybridization technology and extracted from ascites fluid through a Protein G Sepharose affinity column. After labeling with 125I through the chloramine-T method, bFGF mAb was further purified by a Sephadex G-25 column. Gamma radiation counter GC-1200 detected radioactivity of 125I-bFGF mAb. The murine H22 HCC xenograft model was established and randomized to interventions with control (phosphate-buffered saline), 125I-bFGF mAb, 125I plus bFGF mAb, bFGF mAb, or 125I. The ratios of tumor inhibition were then calculated. Expression of bFGF, fibroblast growth factor receptor (FGFR), platelet-derived growth factor, and vascular endothelial growth factor (VEGF) mRNA was determined by quantitative reverse transcriptase real-time polymerase chain ***: The purified bFGF mAb solution was 8.145 mg/mL with a titer of 1:2560000 and was stored at -20 °C. After coupling, 125I-bFGF mAb was used at a 1: 1280000 dilution, stored at 4 °C, and its specific radioactivity was 37 MBq/mg. The corresponding tumor weight in the control, 125I, bFGF mAb, 125I plus bFGF mAb, and 125I-bFGF mAb groups was 1.88 ± 0.25, 1.625 ± 0.21, 1.5 ± 0.18, 1.41 ± 0.16, and 0.98 ± 0.11 g, respectively. The tumor inhibition ratio in the 125I, bFGF mAb, 125I plus bFGF mAb, and 125I-bFGF mAb groups was 13.6%, 20.2%, 25.1%, and 47.9%, respectively. Growth of HCC xenografts was inhibited significantly more in the 125I-bFGF mAb group than in the other groups (P 125I-bFGF mAb group

关键词： Basic fibroblast growth factor 125Iodine Monoclonal antibody Hepatocellular carcinoma Fibroblast growth factor receptor Vascular endothelial growth factor

Effect of deep surface rolling on microstructure and properties of AZ91 magnesium alloy

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Transactions of Nonferrous Metals Society of China 2019年第7期29卷 1424-1429页

作者： Xian LUO Qi-yang TAN Ning MO Yu YIN yan-qing yang Wyman ZHUANG Ming-xing ZHANG School of Materials Science and Engineering Northwestern Polytechnical University Xi’an 710072 China School of Mechanical and Mining Engineering The University of Queensland St. Lucia QLD 4072 Australia Aerospace Division Defence Science and Technology 506 Lorimer Street Fishermans Bend Victoria 3207 Australia

A solution-treated AZ91 bulk material was deep-surface-rolled at room temperature to investigate the effect of deep surface rolling on the microstructure and mechanical properties of the alloy. Microhardness and microstructure along the depth of the treated surface layer were characterized. The results show that the affected layer was up to 2.0 mm thick and consisted of three sublayers: a severe deformation layer with thickness of about 400 μm from the topmost surface, a medium deformation layer with thickness of around 600 μm and a small deformation layer up to 1000 μm thick. In addition to grain refinement in the deformation layer, strain-induced precipitation of β phase (Mg17Al12) was observed, particularly in the severe and medium deformation layers. It is believed that the cooperative effects of grain refinement, strain hardening and precipitation strengthening led to the significant increase in hardness of the AZ91 alloy after the deep surface rolling.

关键词： surface deformation magnesium alloy deep surface rolling microstructural evolution hardness

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青光眼的药物治疗概况

国际眼科杂志 2015年第5期15卷 807-809页

作者：杨燕清李燕昆明医科大学第一附属医院眼科中国云南省昆明市650032

作为全球公认的不可逆致盲眼病,青光眼可出现病理性眼压升高,进行性视神经节细胞及轴突丢失,视杯进行性扩大加深及视野缺损扩大。多种研究认为,兴奋性氨基酸毒性、氧化损伤、细胞内Ca2+超载、细胞凋亡等多种致病因素共同参与了青光眼的... 详细信息

作为全球公认的不可逆致盲眼病,青光眼可出现病理性眼压升高,进行性视神经节细胞及轴突丢失,视杯进行性扩大加深及视野缺损扩大。多种研究认为,兴奋性氨基酸毒性、氧化损伤、细胞内Ca2+超载、细胞凋亡等多种致病因素共同参与了青光眼的发生发展,目前临床上已有多种药物及手术治疗方案来控制青光眼进一步恶化,也有更多新药及方法正在开发过程中。本文就目前抗青光眼药物做一系统概述。

关键词：青光眼视神经保护药物视神经视网膜

Finite element analysis of stress distribution and burst failure of SiC_f/Ti-6Al-4V composite ring

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Transactions of Nonferrous Metals Society of China 2015年第1期25卷 261-270页

作者：张红园杨延清罗贤西北工业大学材料学院凝固技术国家重点实验室西安710072

A three-dimensional cyclic symmetry finite element model of titanium-matrix composites（TMCs） ring was developed to investigate the stress distribution and burst failure. The effects of fiber volume fractions, reinforced areas, thermal residual stresses and two different temperatures on stress distribution were studied. The burst speed was obtained through analyzing the hoop tensile stresses under a series of rotating speeds. The results indicate that at the two different temperatures, the influences of fiber volume fractions and reinforced areas on stress level and distribution are different. Some proposals are provided for the structure design of the TMCs ring. With regard to thermal residual stresses, a larger reinforced area is an advisable choice for design of the ring at higher temperature.

关键词： titanium-matrix composites ring stress distribution burst failure finite element analysis thermal residual stresses