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The effects of different soaking times and cycles of deep cryogenic treatment on the microstructure and mechanical properties of Co28.5Cr21.5Fe20Ni26Mo4 medium entropy alloys were studied. The results show that the maximum hardness and compress strength were 364 HV and 3153 MPa after cryogenic deep treatment for 8 h, which were increased by about 9.97% and 33.32%, respectively. The maximum hardness and compressive strength were 375 HV and 3039 MPa, which were increased by about 13.29% and 28.50%, respectively, after three deep cryogenic cyclic times. The reason is that μ phase is rich in Mo, and Mo element has high strength and hardness. After deep cryogenic treatment, the agglomeration of μ phase in the alloys was improved, the distribution of μ phase was more uniform, the content of μ phase was increased, and the content of Mo element in the μ phase was increased, so that the strengthening effect of μ phase was enhanced.

Inspired by the hierarchical structure of the pearl shell and its related multi-scale toughening mechanism, based on the combination of powder metallurgy technology and spark plasma sintering, a layered graphene and carbon nanotubes hybrid reinforced Cu matrix composite material was successfully prepared. Compared with other conventional Cu matrix composite materials, the compressive elongation of the bionic materials is significantly improved, and all of them are above 20%, which is attributed to the effective crack deflection and the pull-out of the reinforcing phase. In terms of overall strength and toughness, (0.8 wt% MWCNTs+0.2 wt% GNPs)/Cu has the best performance. Its tensile strength, compressive strength and compressive elongation are 103.63 MPa, 202.32 MPa and 33.49% respectively. The large grain size in the laminates is conducive to the movement of dislocations, while the interlayer interface and nanocrystalline grains hinder the movement of dislocations in the direction perpendicular to the laminates.

Cu–Al–Mn–Ti–xTa alloys (x = 0, 1, 2, 3, wt.%) prepared by spark plasma sintering were investigated for the effect of Ta content on the microstructure, mechanical and damping properties. The microstructure and phase composition indicate that the alloy is mainly composed of β′1 martensite, γ′1 martensite, Ti-rich and Ta-rich phase. As the Ta content increases, the grain size of the alloy first decreases and then increases. The reverse trend was observed for hardness, tensile and compressive strength. The hardness, tensile strength and compressive strength increased by 18.2%, 44.9% and 28%, respectively, when the Ta content was 1 wt.% compared to the alloy without Ta element. The presence of martensite provides the alloy with promising damping properties. Meanwhile, the formation of the second phase has a two-sided effect on the damping characteristics. That is, the increase in grain boundaries provides more interfaces for energy dissipation, but the increased compressive stress between the interfaces also hinders the movement of the interfaces. Excellent damping performance is demonstrated with the addition of 1 wt.% of Ta element. The peak values of damping capacity at room temperature and at about 580 °C reached 0.026 and 0.19, respectively. The results confirm that the addition of Ta elements is achievable to obtain Cu–Al–Mn–Ti alloys with both high mechanical and damping properties.

As an ideal reinforcing phase, nano-carbon has been widely used to improve the properties of composites. In this paper, Mo–Cu–Zr ternary composites were reinforced with various types and contents of nano-carbon to find the optimal composition and the microstructure and mechanical properties of the composites were systematically characterized and analyzed. The composites were fabricated via a powder metallurgy method to achieve high compactness and structural uniformity. The analysis results show that the increase of nano-carbon may cause a serious agglomeration and subsequent decrease of the composite compactness, while the synergetic effect of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) can improve their dispersion. The 0.8C + 0.2G-MCZ3 composite showed the best comprehensive properties, which achieved a relative density, hardness and compressive strength of 99.7%, 343.6 HV and 953.5 MPa, respectively. Moreover, the component Zr mainly formed solid solution and compound particles with Cu or C through in-situ chemical reactions. It played an important role in solid solution strengthening and dispersion strengthening, and the in-situ synthesized ZrC nanoparticles on nano-carbon surfaces can pin interfaces and improve the effect of load transfer. The synergetic effects and multiple strengthening mechanisms result in the improvement of the microstructure and properties of the composites.

Cu–Al-based alloys are a kind of new functional material. Due to their unique thermoelastic martensite structure, they have excellent damping performance, which has become a research hotspot in the field of materials science and engineering in recent years. However, the elastic anisotropy and large grain size easily cause a brittle fracture, which is harmful to the mechanical properties of the material. In order to meet the practical needs of engineering, it is an important choice to design Cu–Al-based alloys with excellent mechanical properties and damping performances from the perspective of refining the grain size. When the grain size is small, the effect of fine grain strengthening and interfacial damping can play a role simultaneously to obtain Cu–Al-based alloys with excellent comprehensive properties. In this paper, several common preparation methods of Cu–Al-based alloy are introduced firstly. Then the contributions of researchers in refining grain size from alloying and heat treatment are summarized. Meanwhile, nanomaterials can be used as the reinforcing phase of Cu–Al based alloy, and play a superb role in mechanical properties and damping performances. The purpose of this study is to provide a reference for the further research of structure-function integrated materials with high strength and high damping simultaneously. Finally, the development of Cu–Al-based alloy from the aspects of 3D printing and numerical simulation is prospected.

High-entropy alloys (HEAs) have become a research focus because of their easy access to nanostructures and the characteristics of high strength, hardness, wear resistance, and oxidation resistance, and have been applied in aerospace lightweight materials, ultrahigh temperature materials, high-performance materials, and biomimetic materials. At present, the study of HEAs mainly focuses on the microstructure and mechanical properties. HEAs of Mo, Ti, V, Nb, Hf, Ta, Cr, and W series have high strength, while HEAs of Fe, Co, Ni, Cr, Cu, and Mn series have good toughness. However, the emergence of medium-entropy alloys, metastable HEAs, dual-phase HEAs, and multiphase HEAs increased the complexity of the HEA system, and the phase transition mechanism and strengthening and toughening mechanisms were not fully established. In this article, the preparation, phase formation, phase transformation as well as strengthening and toughening mechanisms of the HEAs are reviewed. The inductive effects of alloying elements, temperature, magnetism, and pressure on the phase transformation were systematically analyzed. The strengthening mechanisms of HEAs are discussed, which provides a reference for the design and performance optimization of HEAs.

In this work, α-Al2O3 whisker reinforced Cu-graphite matrix composites were prepared by spark plasma sintering. Results show that the surface modification of α-Al2O3 whiskers with sodium dodecyl sulfate solution can improve its dispersibility, and the composites obtained are basically completely dense. The relative density of all composite materials is above 95%. The interface bonding mode in the composite is mainly mechanical bonding, and the formation of a diffusion layer is also observed from interfaces. With the increase of α-Al2O3 whisker content, mechanical properties of the composites increase first and then decrease. The composite with 1.0 wt% α-Al2O3 whisker has the best performance. The corresponding relative density, hardness and compressive strength are 96.35%, 56.20 HV, 139.12 MPa, respectively. By analyzing microstructure and fracture morphology of the composites, it is determined that the strengthening mechanisms are mainly fine grain strengthening, particle strengthening and load transfer. Simultaneously, the fracture type is brittle fracture., This work was supported by Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences (No.IIMDKFJJ-19-08) and China Postdoctoral Science Foundation (No. 2015M570794, No. 2018T110993).

In this study, nonequiatomic Co28.5Cr21.5Fe20Ni26Mo4 medium-entropy alloys (MEAs) were prepared using hot isostatic pressing. The effect of annealing heat treatment on microstructure and mechanical properties of MEAs was investigated. The results showed that the microstructure of as-sintered alloys was mainly composed of the face-centered cubic (FCC) phase and μ phase. The presence of the μ phase could improve the compressive strength of Co28.5Cr21.5Fe20Ni26Mo4 MEAs. Meanwhile, the ductile FCC phase matrix could effectively suppress the propagation of cracks to improve its ductility. Hence, as-sintered MEAs possessed excellent compression properties, and the average compressive strength value was 2,606 MPa when the strain was 50%. Compared with as-sintered MEAs, the phase composition of as-annealed MEAs did not change. The micro-hardness of annealed MEAs was stable compared to as-sintered MEAs (342 HV), and its fluctuation was about ±30 HV. The compressive strength of the annealed MEAs did not alter greatly, and the maximum fluctuation value was only about 6.5%. Hence, Co28.5Cr21.5Fe20Ni26Mo4 MEAs had excellent thermal stability.

With the development of economy, international trade and commerce frequently boomed, multicultural families are gradually increasing, so developing children’s bilingual competence has become a focused issue. This thesis collects 38 Korean-Chinese children’s bilingual proficiency test paper to research language bidirectional transfer in the process of K-C children bilingual acquisition. There are two types of children involved, that one is bilingual children who born in china, with a Korean parent and a Chinese parent; the other type is early second acquisition children who came to China before the age of three, and their parents are both Korean. Early second acquisition children have lived in a Chinese environment since childhood. Based on the influence of bilingual language community and early childhood education intervention, they input Chinese signals implicitly, and started to learn Chinese systematically in kindergarten at around age of three. Two types of children are affected by language transfer from Korean and Chinese. As far as the pronunciation is concerned, K-C children have difficulty in identifying Pinyin, recognition of tone labeling, and pronunciation of speech cross languages; in terms of syntax, K-C children show object-verb inversion and shift of topic focus of prepositional verb. This thesis mainly involves error analysis of speech and syntactic structure, classification of error item, to study the cross-lingual impact between Chinese-Korean in children’s bilingual acquisition who are under the Chinese environment, which will help to build dynamic schema of bidirectional transfer in K-C children language acquisition, and final finally give some suggestions.

Background This study aimed to explore the association between diabetes mellitus and health-related quality of life (HRQoL) of older people in Shanghai, China, especially regarding the differences in each aspect of the EQ-5D and how large the score gaps are between older people with and without diabetes. Methods A total of 11,103 people of either sex older than 60 years were enrolled from 17 districts of Shanghai. The EQ-5D-3L was used to assess the HRQoL of older people. The Wilcoxon rank sum test and t-test were used to compare the difference in HRQoL between people with or without diabetes. After univariate regression, multiple linear regression and ordinal logistic regression were conducted to evaluate the influence of diabetes mellitus and other confounding variables on the EQ VAS scores and on the five dimensions of the EQ-5D. Results Twelve percent of all participants had diabetes mellitus, and the proportion was almost the same between men and women. The EQ VAS scores of people with diabetes mellitus were approximately 3.70 points lower than those of people without diabetes (95% CI = -4.40, -2.99, p Conclusions This study showed that diabetes mellitus was associated with the HRQoL of older people and that older people with diabetes had poorer performance in every aspect of EQ-5D measurements.

The multiphase co-reinforcing composite combines the advantages of different reinforcing phases to give composite superior properties. In this study, nano-carbon and hexagonal boron nitride (HBN) reinforced Cu-Ti3SiC2-C composites are fabricated by surface modification, ball milling, vacuum hot pressing (VHP) and hot isostatic pressing (HIP). The content of nano-carbon is 0.5 wt%, and the ratio of multi walled carbon nanotubes (MWCNTs) to graphene was 4:1, 1:1 and 1:4, respectively. Microstructure and mechanical properties of the prepared composites are systematically tested and analyzed. Results show that the interface bonding mode between the reinforcements and matrix is mainly mechanical locking. The composite with the ratio of MWCNTs to graphene is 4:1 shows the best properties in which the hardness, tensile, compressive and shear strength are 121.91 HV, 163.87 MPa, 431.86 MPa and 122.56 MPa, respectively. The reinforcements improve the properties of composites by the mechanisms of load transfer, fine grain strengthening, particle strengthening and anti-friction lubrication., This work was supported by Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences (No.IIMDKFJJ-17-06), National Natural Science Foundation of China (No. 51201143), China Postdoctoral Science Foundation (No. 2015M570794, No. 2018T110993).

Multi-walled carbon nanotubes (MWCNTs) and graphene synergetically reinforced Cu–graphite matrix composites with alloying elements and the rare earth element lanthanum were fabricated by powder metallurgy, and their mechanical properties were evaluated. An innovative solution for dispersing the solution into the MWCNTs and graphene was adopted by surface modification with gallic acid solution or rutin solution, instead of strong acid and base solutions, respectively. The interfacial bonding between MWCNTs or graphene and the copper matrix, and the particle distribution uniformity, were enhanced by mechanical alloying and freeze-drying. Nearly complete densification of the MWCNTs and graphene synergetically reinforced Cu–graphite matrix composites was achieved by hot-pressing and hot isostatic pressing sintering. The microstructure and mechanical properties of the composites indicated that the interfaces between the reinforcing phases and matrix were tightly bonded, confirming that the interface bonding between the MWCNTs, graphene, and copper matrix was mainly established as mechanical locks. The dominant strengthening mechanisms in the composites were the fine grain strengthening, load transferring, and solution strengthening, followed by dislocation strengthening.

Biolinguistics is an interdisciplinary subject derived from the interaction of biology and linguistics. In 1967, after the publication of Biological Foundations of Language by Lenneberg E.H., the vision of Language study has been introduced into the field of biology. Later, Chomsky proposed the term of language faculty and regarded language as “an organ of the body”. Different from traditional linguists’ description of the rules of language externalization, Chomsky focuses on the biological mechanism of internalized language. The challenge of theory of evolution in biology has also enriched the study of the origin and evolution of language. This thesis will begin with the mythological origin and philosophical foundation of language, chase the challenge of evolutionary theory, and discuss two groups of basic properties of language, which is unity and diversity, recursiveness and thinking, so as to further study the relation between language and its biological basis, that is, from language and speech organ, language and thought to language and gene, to analyze the uniqueness of human language competence.

Poor corrosion resistance and osseointegration of titanium/hydroxyapatite (Ti/HA) composites or coatings limit their application of long-term implants. In this study, spark plasma sintering was employed to fabricate Ti/HA nanocrystalline composites, in which HA was proposed to improve osseointegration of Ti alloys and surface-functionalized nanocarbons (graphene nanoflakes (GNFs) and carbon nanotubes (CNTs)) were proposed to improve corrosion resistance and osteogenicity of Ti/HA nanocomposites. The microstructures indicated that phase transition of Ti, HA decomposition and chemical reaction occurred during sintering and typical microstructural characteristics such as porosity, dislocations, polycrystalline compounds or secondary compounds were present in the Ti/HA nanocomposites. The electrochemical behavior showed that Ti/HA nanocomposites containing graphenes (0.5 GNFs and 0.4CNT/0.1GNFs) had better corrosion resistance compared to other composites (0.5 CNTs and nonreinforced). The embedded graphene acted as an efficient barrier against ionic diffusion, thus causing an effective shielding against corrosion. In vitro cytocompatibility and osteogenesis evaluation demonstrated that 0.4CNT/0.1GNF-reinforced Ti/HA nanocomposites led to optimal osteoblast adhesion and proliferation, support of osteogenic differentiation and osteogenic activity. In summary, overall, considering the corrosion resistance, cytocompatibility and osteogenesis of the Ti/HA nanocomposites, 0.4CNT/0.1GNF-reinforced Ti/HA nanocomposites had acceptable corrosion resistance and optimal cytocompatibility and osteogenicity, making it a potentially feasible bone implant biomaterial., We would like to thank Dr. Xingzhi Liu (School of Nano-Tech and Nano-Bionics, University of Science and Technology of China), who contributed to this study for the in vitro cytocompatibility and osteogenesis tests of our Ti/HA nanocomposite. This work was supported by the Sichuan Science and Technology Support Program (No. 2016FZ0079) and China Postdoctoral Science Foundation (No. 2017M623054 and No. 2018T110993)., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Objectives Using the person-environment (PE) fit theory, this study aims to explore factors affecting medical professionals’ job satisfaction, turnover intention, and professional efficacy, and to examine individual characters associated with PE fit. Design and methods This study used data from the sixth National Health Service Survey conducted in 2018, with a focus on job outcomes among medical professionals in Shanghai. The reliability and validity of the tools for measuring PE and job outcomes were calculated. A structural equation model was used to examine the relationship among person-job (PJ) fit and person-group (PG) fit, job satisfaction, turnover intention, and professional efficacy. Finally, a hierarchical regression model was used to analyze the association between demographic variables and the PJ and PG fit. Results PG fit was directly and positively associated with job satisfaction and professional efficacy. PJ fit had a direct and positive association with job satisfaction but had a direct and negative association with turnover intention. The indirect association of PJ fit with turnover intention was statistically significant. The results from the hierarchical regression analysis showed that younger physicians generally had a lower level of PJ fit and older physicians with higher education tended to have a lower level of PG fit. Conclusions Medical professionals with higher PJ or PG fit have higher job satisfaction, and those with higher PG fit have higher professional efficacy. The impact of PJ fit on turnover intention was mediated by job satisfaction. Healthcare managers should take actions to effectively promote medical professionals’ PJ and PG fit to improve their retention and efficiency.

The effects of Y content on the microstructure, mechanical and damping properties of Cu-11Al-3Ni-2.5Mn-χY (χ = 0, 0.5, 1, 2, wt.%) alloys were investigated. The results of X-ray diffraction (XRD) analysis showed that the alloy was mainly composed of 18R martensite, α-Cu and γ2-Cu9Al4. The Y2O3 particles appear after the addition of Y elements. The grain size is reduced to 36.5 μm when 1 wt.% Y element was added, and the combined effect of the grain size reduction and the Y2O3 particles increases the tensile strength to 601.75 MPa. Meanwhile, the alloy at this content has high damping properties, the damping peaks at room temperature and temperature 600 °C were 0.038 and 0.24, respectively.

In this paper, the solid-state welding and fusion welding of high-entropy alloys (HEAs) were reviewed. For solid-state welding of HEAs, the influence of microstructure change and welding parameters on properties of welded joints were discussed. For fusion welding of HEAs, the application of laser welding, electron beam welding and gas tungsten arc welding was analyzed. Then relevant welding mechanisms, solidification behavior of grains, and phase formation in fusion welding of HEAs were discussed. The methods optimizing properties and microstructure of welded joints were discussed, including the adjustment of parameters, usage of pre-welding heat treatment and post-welding heat treatment, as well as the application of metallic interlayers in dissimilar welding of HEAs. The application of numerical simulation in HEAs welding could facilitate the optimization of experimental parameters. In addition, HEAs have been applied as coatings to improve the properties and life of materials based on welding methods, and the application of HEAs fillers in welding was also achieved. In the future, molecular dynamics simulation can be applied to analyze the atomic diffusion and stress distribution in HEAs welding, and there are still many aspects that need to be explored in the field of HEAs welding.

Dissimilar joining of Ti-6Al-4V titanium alloy and AISI316L stainless steel was investigated in the current study by diffusion bonding using Cu/Nb multi-interlayer. Effects of the bonding temperature and bonding time on microstructure and mechanical properties were studied in the range of 850–950 °C. Microstructural characterization was carried out through optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Results showed that when the bonding temperature is 900 °C or below, the formation of intermetallic compounds was successfully prevented and strong TiA/α-β Ti/Nb/Cu/SS diffusion bonding joints were achieved by inserting a Cu/Nb multi-interlayer. A minimum hardness value of 99 HV was measured in the joint zones and maximum tensile strength of 489 MPa is accomplished when the joints processed at 900 °C for 90 min. Fracture analysis results showed different fracture morphologies at different bonding temperatures. Fracture took place though Cu/Nb interface at lower parameters then transferred to remnant Cu layer at 900 °C for 90 min with extensive dimples on the surfaces, displaying a ductile nature. However, bonded at 950 °C for 90 min, joints fractured along the intermetallic compounds upon tensile tests, indicating a brittle nature.

Diffusion bonding is a near net shape forming process that can join dissimilar materials through atomic diffusion under a high pressure at a high temperature. Titanium alloy TC4 (Ti-6A1-4V) and 4J29 Kovar alloy (Fe-29Ni-17Co) were diffusely bonded by a vacuum hot-press sintering process in the temperature range of 700–850 °C and bonding time of 120 min, under a pressure of 34.66 MPa. Interfacial microstructures and intermetallic compounds of the diffusion-bonded joints were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The elemental diffusion across the interface was revealed by electron probe microanalysis. Mechanical properties of joints were investigated by micro Vickers hardness and tensile strength. Results of EDS and XRD indicated that (Fe, Co, Ni)-Ti, TiNi, Ti2Ni, TiNi2, Fe2Ti, Ti17Mn3 and Al6Ti19 were formed at the interface. When the bonding temperature was raised from 700 to 850 °C, the voids of interface were reduced and intermetallic layers were widened. Maximum tensile strength of joints at 53.5 MPa was recorded by the sintering process at 850 °C for 120 min. Fracture surface of the joint indicated brittle nature, and failure took place through interface of intermetallic compounds. Based on the mechanical properties and microstructure of the diffusion-bonded joints, diffusion mechanisms between Ti-6A1-4V titanium and Fe-29Ni-17Co Kovar alloys were analyzed in terms of elemental diffusion, nucleation and growth of grains, plastic deformation and formation of intermetallic compounds near the interface.

// Yuntao Chen 1, 2, * , Zhenyi Shao 2, * , Wen Chen 2 , Hua Xie 2 , Zhenyu Wu 1, 2 , Guoyou Qin 1, 2 , Naiqing Zhao 1, 2 1 Department of Biostatistics, School of Public Health and Key Laboratory of Public Health Safety, Fudan University, Shanghai 200032, China 2 Collaborative Innovation Center of Social Risks Governance in Health, Fudan University, Shanghai 200032, China * Co-first authors Correspondence to: Guoyou Qin, email: gyqin@fudan.edu.cn Naiqing Zhao, email: nqzhao@shmu.edu.cn Keywords: CA19-9, pancreatic cancer, varying coefficient model, biomarker, prognosis Abbreviations: PC: pancreatic cancer; OS: overall survival; CA19-9: carbohydrate antigen 19-9; PH: proportional hazard; HR: hazard ratio. Received: August 16, 2016 Accepted: January 23, 2017 Published: February 21, 2017 ABSTRACT Purpose: To evaluate the relationship between serum CA19-9 and overall survival in patients with advanced pancreatic cancer. Methods: 109 advanced pancreatic cancer patients with gemcitabine based first-line chemotherapy were included. The effect of pretreatment CA19-9 level on overall survival was modeled by Cox proportional hazard regression. The effect of CA19-9 kinetics on overall survival was modeled by an extended Cox regression with a time varying coefficient and a time varying covariate. Results: Univariate analysis indicated that baseline CA19-9 correlated with OS (HR = 1.66, p < 0.01) and this association remained significant within multivariate analysis (HR = 1.56, P < 0.01). For the analysis of CA19-9 kinetics, the extended Cox model showed that the effect of CA19-9 on overall survival changed with time: increased in the first two months and reached the top at a HR of about 2, then decreased for the next two months to a HR of about 1.56 and finally tended to be stable. The combination of pretreatment CA19-9 and CA19-9 at 2 month may better evaluate the patients’ prognosis compared to pretreatment CA19-9 alone. Conclusion: Pretreatment CA19-9 and CA19-9 kinetics may serve as a useful serum biomarker in advanced pancreatic cancer.

Al-Si alloy nanocomposites reinforced with nano-carbon (carbon nanotubes (CNTs), graphene nanoplatelets (GNPs)) and in-situ Al2O3 were fabricated via the process of surface modification, ball milling and hot isostatic pressing (HIP). The microstructure and mechanical properties of the nanocomposites were tested and analyzed. The interface between nano-carbon and Al matrix bonded tightly for reacting at the interface to form Al4C3, and the in-situ synthesis Al2O3 particles were dispersively distributed and had high bond strength with Al matrix. The nanocomposites show high compactness (≥98.5%) and excellent mechanical properties, the hardness, tensile, compressive and shear strength of the nanocomposite with 1.0 wt% CNTs are 96.4 HV, 237.7 MPa, 389.5 MPa and 130.3 MPa, respectively. The interface bonding mechanisms and strengthening mechanisms were studied in detail. The results show that the reinforcement phases mainly reinforce the nanocomposites by grain refinement strengthening, dislocations strengthening, particles strengthening and load transfer.

Mo–Cu composites exhibit excellent physical and mechanical properties, while the problems of densification and interface seriously limit their application. In this paper, the effect of element Zr on the properties of Mo–Cu composites is investigated aiming to overcome these critical issues. Various compositions of Mo–Cu–Zr ternary composites were fabricated via ball milling, cold isostatic pressing and microwave sintering. Microstructures and mechanical properties of the prepared composites were systematically characterized and analyzed. The results show that the density and mechanical properties of the composites increase with the increase of Zr content, and the 50Mo30Cu20Zr composite achieves the highest relative density of 97.6%, hardness of 314.4 HV and compressive strength of 805.9 MPa. The increase of Zr content reduces the sintering activation energy and leads to the improvement of density. Simultaneously, the element Zr can form solid solutions and in-situ synthesis intermetallic compounds with Cu matrix, which leads to solid solubility strengthening and dispersion strengthening. Moreover, the interface between Mo and Cu phase is found to have been reinforced by the in-situ intermetallic compound particles embedded in the interface. This work provides an important reference for research of densification and mechanical property of Mo–Cu composites.

Natural materials usually have excellent performance for their special structures. Learning from the nature may catalyze the creation of artificial composites with unprecedented performance and functionalities. To realize this bio-inspired design idea on nano-carbon reinforced metal matrix composites, it is indispensable to understand and quantify the design principles of natural materials and consider the inherent characteristics of artificial materials and conditions of engineering applications. In this paper, recent researches of the bio-inspired nano-carbon reinforced metal matrix composites are reviewed to highlight the scientific and technological questions to obtain the bio-inspired structure artificial composites. These include the fabrication methods for solving the dispersion problem of nano-carbon and achieving the bio-inspired structure, characterization of microstructure and properties of bio-inspired composites. The interface and reinforcement mechanisms are emphatically investigated and discussed, in this way to help unveil natural design principles and provide reference for the future research of bio-inspired composites., This work was supported by Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences (No. IIMDKFJJ-17-06), National Natural Science Foundation of China (No. 51201143), China Postdoctoral Science Foundation (No. 2015M570794, No. 2018T110993).

Researches have shown that the addition of trace amounts of rare earth element lanthanum (La) to the alloys and composites can significantly improve their microstructure and properties. In this work, Cu/Ti3SiC2/C composites with 0.05wt%, 0.1wt% and 0.3wt% La were prepared by powder metallurgy methodthrough mechanical alloying, hot-pressing (HP) and hot isostatic pressing (HIP). The effects of different La contents on the microstructure and mechanical properties of Cu/Ti3SiC2/C composites were investigated. The results show that La has a refinement effect on the grain of the matrix, and with the increase of La content, the size of the matrix of the composite becomes smaller. As the content of La increases, the performance of the composite exhibits a tendency to increase first and then decrease. The composite of 0.1wt% La exhibited the best performance with a hardness of 97.8 MPa, a tensile strength of 174.9 MPa, and a compressive strength and shear strength of 461.1 MPa and 102.1 MPa, respectively. Since the dimple is observed, the tensile fracture indicates that the fracture mode is a ductile fracture. The enhancement mechanism of La mainly includes dispersion strengthening and fine grain strengthening.

Nano-carbon reinforced titanium matrix/hydroxyapatite (HA) biocomposites were successfully prepared by spark plasma sintering (SPS). The microstructure, mechanical properties, biocompatibility, and the relationship between microstructure and properties of biocomposites were systematically investigated. Results showed there are some new phases in sintered composites, such as &beta, Ti, TiO3, ZrO2, etc. Moreover, a small amount of Ti17P10, CaTiO3, Ca3(PO4)2 were also detected. The reaction that may occur during the preparation process is suppressed to some extent, which is because that the addition of second phases can prevent the direct contact of titanium with HA and reduce the contact areas. Transmission electron microscope (TEM) analysis proved the existence of elemental diffusion and chemical reactions in sintered composites. Compared with results of composites prepared by hot-pressed sintering before, mechanical properties (microhardness, compressive strength, and shear strength) of 0.5-GNFs composites prepared by SPS were increased by about 2.8, 4.8, and 4.1 times, respectively. The better mechanical properties of 0.5-GNFs composite in nano-carbon reinforced composites are mainly due to the lower degree of agglomeration of tubular carbon nanotubes (CNTs) compared to lamellar graphene nanoflakes (GNFs). Moreover, the strengthening and toughening mechanisms of nano-carbon reinforced titanium alloy/HA biocomposite prepared by spark plasma sintering (SPS) mainly included second phase strengthening, grain refinement strengthening, solution strengthening, graphene extraction, carbon nanotubes bridging, crack tail stripping, etc. In addition, in vitro bioactivity test revealed that the addition of nano-carbon was beneficial to promote the adhesion and proliferation of cells on the surface of titanium alloy/HA composite, because nano-carbon can enhance the formation of mineralized necks in the composites after transplantation, stimulate biomineralization and promote bone regeneration.

Titanium alloy/Hydroxyapatite (HA) composites have become a hot research topic in biomedical materials, while there are some challenges concerning bioactivity and mechanical properties such as low interface adhesion at the interface between metal and ceramic, complex interfacial reactions, and so on. Nevertheless, composites with reinforced phases can reach special properties that meet the requirements of biomedical materials due to the strong interfacial interactions between reinforcing phases (nano-carbon, partial oxides, and so on) and Titanium alloys or HA. This review summarizes the interface properties and mechanisms of Titanium alloy/HA composites, including interfacial bonding methods, strengthening and toughening mechanisms, and performance evaluation. On this basis, the interface characteristics and mechanisms of the Titaniumalloy/HA composites with enhanced phase are prospected. The results show that the interfacial bonding methods in the Titanium alloy/HA composites include chemical reactions and mechanical effects. The strengthening and toughening mechanisms contain grain refinement strengthening, second phase strengthening, solution strengthening, cracks and pulling out mechanisms, etc. This review provides a guidline for the fabrication of biocomposites with both mechanical properties and bioactivity.

Single-crystal &alpha, Al2O3 fibres can be utilized as a novel reinforcement in high-temperature composites owing to their high elastic modulus, chemical and thermal stability. Unlike non-oxide fibres and polycrystalline alumina fibres, high-temperature oxidation and polycrystalline particles boundary growth will not occur for single-crystal &alpha, Al2O3 fibres. In this work, single-crystal &alpha, Al2O3 whiskers and Al2O3 particles synergistic reinforced copper-graphite composites were fabricated by mechanical alloying and hot isostatic pressing techniques. The phase compositions, microstructures, and fracture morphologies of the composites were investigated using X-ray diffraction, a scanning electron microscope equipped with an X-ray energy-dispersive spectrometer (EDS), an electron probe microscopic analysis equipped with wavelength-dispersive spectrometer, and a transmission electron microscope equipped with EDS. The mechanical properties have been measured by a micro-hardness tester and electronic universal testing machine. The results show that the reinforcements were unevenly distributed in the matrix with the increase of their content and there were some micro-cracks located at the interface between the reinforcement and the matrix. With the increase of the Al2O3 whisker content, the compressive strength of the composites first increased and then decreased, while the hardness decreased. The fracture and strengthening mechanisms of the composite materials were explored on the basis of the structure and composition of the composites through the formation and function of the interface. The main strengthening mechanism in the composites was fine grain strengthening and solid solution strengthening. The fracture type of the composites was brittle fracture.

Background: Elevated pretreatment lactate dehydrogenase (LDH) has been reported to be associated with poor survival in small cell lung cancer (SCLC). The present study aimed to investigate the continuous relationship between baseline LDH level and survival in patients with extensive-disease SCLC (ED-SCLC). Methods: Data were retrospectively collected from Shanghai Health Information Network. Patients primarily diagnosed as ED-SCLC from April 2011 to August 2014 were eligible for our study. Patients’ survival status was checked in March 2016. A multivariate Cox proportional hazard model was used to detect the association between baseline serum LDH and overall survival. The corresponding continuous relationship was analyzed by using natural spline functions in the Cox model. Results: A total of 132 eligible ED-SCLC patients were analyzed. Elevated LDH at baseline was associated with poor survival (HR =1.92; 95% CI, 1.29–2.86). An increment of LDH would still raise the risk of death even in abnormal range. Among patients with elevated LDH, those who had relatively higher LDH levels (>370 U/L) would have a poorer prognosis than those with moderately elevated LDH levels (245–370 U/L; median survival time, 114 vs . 274 days; P value of log rank test, 0.007). Conclusions: LDH is a significant prognostic biomarker for ED-SCLC patients. The interpretation of continuous relationship between LDH and patients’ survival can provide more accurate information for clinical practice.

Copper-graphite composite is an ideal friction material due to its good heat resistance, wear resistance and friction coefficient stability. The addition of Ti3SiC2 can improve strength, hardness and wear resistance of copper-graphite alloy material without affecting its self-lubricating properties and electrical conductivity. Two-dimensional graphene has become an attractive composite reinforcement owing to their unique electrical, mechanical and thermal properties. Cu/Ti3SiC2/C/Graphene naocomposite materials reinforced with graphene have been fabricated by vacuum hot-pressing sintering and hot isostatic pressing. Microstructures and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials with different graphene contents have been systematically investigated. Microstructures of the composites were examined by optical microscopy, X-ray diffraction, back scattered electron imaging, scanning electron microscope with energy dispersive spectrometer and transmission electron microscope. The mechanical properties were determined from Brinell hardness, tensile, compressive and shear tests. Results demonstrated that there was an optimum value of graphene content which has an impact on microstructures and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials. Based on graphene content on microstructure and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials, strengthening and fracture mechanisms by graphene reinforcement have been analyzed.

The prognostic relevance of commonly used composite inflammation-based scores remains severely underdiscussed in pancreatic cancer (PC), especially for advanced PC. In this retrospective cohort study, we aimed to discuss the association between multiple inflammatory scores and the short-term overall survival (OS) of advanced pancreatic ductal adenocarcinoma (PDAC) patients. A total of 66 histologically confirmed PDAC patients were retrospectively analyzed. A multivariate Cox proportional hazards model was used to explore the association between 6 commonly used inflammatory scores measured right after diagnosis, Glasgow Prognostic Score (GPS), Modified Glasgow Prognostic Score (mGPS), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), prognostic index (PI), prognostic nutritional index (PNI), and the short-term OS of advanced PDAC. Analytical results revealed that among GPS, mGPS, NLR, PLR, PI and PNI only PLR was significantly associated with short-term OS of PDAC. For both 1-year and 2-year OS, every 10 increase of PLR value resulted in 1.10 (95% CI: 1.04, 1.16) folds hazard ratio (HR). Further analysis identified a statistically significant dose–response relationship between PLR and HR. Our study results probably suggested that PLR is a promising prognostic factor of advanced PDAC; maintaining normally ranged platelet count may gain short-term survival benefit among such patients.

Cu/Ti3SiC2/C/MWCNTs composites were prepared by vacuum hot-pressing sintering. Microstructures and mechanical properties of Cu/Ti3SiC2/C/MWCNTs composites with different multi-walled carbon nanotubes contents have been systematically investigated. The microstructures of the composites were examined by optical microscopy, X-ray diffraction, back scattered electron imaging, scanning electron microscope and energy dispersive spectrometer. The mechanical properties were determined from Brinell hardness and tensile tests. The results demonstrated that there was an optimum value of MWCNTs content which has an impact on microstructures and mechanical properties of Cu/Ti3SiC2/C/MWCNTs composites. Based on MWCNTs content on properties and microstructure of Cu/Ti3SiC2/C/MWCNTs composites, effects of MWCNTs on improvement of the composites and strengthening mechanism have been analyzed.

Multi-walled carbon nanotubes (MWCNTs) and graphenes have been taken for novel reinforcements due to their unique structure and performance. However, MWCNTs or graphenes reinforced copper matrix composites could not catch up with ideal value due to reinforcement dispersion in metal matrix, wettability to metal matrix, and composite material interface. Taking advantage of the superior properties of one-dimensional MWCNTs and two-dimensional graphenes, complementary performance and structure are constructed to create a high contact area between MWCNTs and graphenes to the Cu matrix. Mechanical alloying, hot pressing, and hot isostatic pressing techniques are used to fabricate Cu matrix self-lubricating nanocomposites. Effects of MWCNTs and graphenes on mechanical properties and microstructures of Cu/Ti3SiC2/C nanocomposites are studied. The fracture and strengthening mechanisms of Cu/Ti3SiC2/C nanocomposites are explored on the basis of structure and composition of Cu/Ti3SiC2/C nanocomposites with formation and function of interface.