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Lightweight,Strong and High Heat-Resistant Poly(lactide acid)Foams via Microcellular Injection Molding with Self-Assembly Nucleating Agent

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Chinese Journal of Polymer Science 2024年第6期42卷 739-750页

作者： xiao-Hu bing Wen-Yu ma Ming-Hui Wu Peng Gao xiao Zhou Hai-bin Luo Long Wang Wen-Ge Zheng School of materials Science and Engineering Shanghai UniversityShanghai200444China Ningbo Key Lab of Polymer materials Ningbo Institute of Material Technology and EngineeringChinese Academy of SciencesNingbo315201China University of Chinese Academy of Sciences Beijing100049China

Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)***,PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt *** this study,a high-performance PLA foam with well-defined cell morphology,exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding(MIM)*** scanning calorimetry(DSC)results revealed that the added hydrazine-based nucleating agent(HNA)significantly increased the crystallization temperature and accelerated the crystallization process of ***,the addition of a 1.5 wt%of HNA led to a significant reduction in PLA’s cell size,from 43.5µm to 2.87µm,and a remarkable increase in cell density,from 1.08×10^(7)cells/cm^(3)to 2.15×10^(10)cells/cm^(3).This enhancement resulted in a final crystallinity of approximately 55.7%for the PLA blend foam,a marked improvement compared to the pure PLA ***,at 1.5 wt%HNA concentration,the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136%and 463%,***,the Vicat softening temperature of PLA blend foam increased significantly to 134.8°C,whereas the pure PLA foam exhibited only about 59.7℃.These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance,which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.

关键词： Poly(lactide acid) Nucleating agent Microcellular injection molding Heat-resistance Toughness

High-entropy oxide-supported platinum nanoparticles for efficient hydrogen evolution reaction

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Rare Metals 2024年第4期43卷 1537-1546页

作者： Ming-Yu Fan Jia-Jun Wang Jun Zhao Hong Zhang Tian-Yi ma xiao-Peng Han Wen-bin Hu School of materials Science and Engineering Tianjin Key Laboratory of Composite and Functional Materials Key Laboratory of Advanced Ceramics and Machining TechnologyTianjin UniversityTianjin300350China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou350207China School of Science RMIT UniversityMelbourneVIC3000Australia

High-entropy oxides(HEOs)are a new class of single-phase structures with unique electronic and catalytic properties;therefore,it is worthwhile to explore their applications in *** this study,a Pt/(FeCoNiCrAl)_(3)O_(4)nanohybrid using HEO as a support was developed as an efficient catalyst for the hydrogen evolution reaction(HER).Pt/(FeCoNiCrAl)_(3)O_(4)exhibited high HER activity with a low overpotential of 22 mV at10 ma·cm^(-2),outperforming other binary,ternary,and quaternary *** HER activity of Pt/(FeCoNiCrAl)_(3)O_(4)was higher than that of a commercial Pt/C with a significantly lower Pt *** catalyst exhibited good activity and long-term stability(60 h)in an electrolytic water-splitting *** good activity can be attributed to the fact that the introduction of Pt effectively facilitates electronic interactions between Pt and the *** addition,the HEO substrate was more favorable for dispersing Pt particles,optimizing the electrochemical specific surface area,and significantly reducing the charge resistance of the *** study extends the application of HEOs in electrocatalysis and demonstrates the promising prospects of HEOs as supports for electrocatalysts.

关键词： High-entropy oxides Hydrogen evolution reaction Nanohybrid Water electrolysis

A new method for evaluating wedges of steel plates and strips

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Journal of Iron and Steel Research(International) 2024年第7期31卷 1719-1735页

作者： xiao-bao ma xiao-xin ma Tao Wang Zhong-kai Ren Yu-cheng Ren College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024ShanxiChina Ministry of Education Engineering Research Center of Advanced Metal Composite Forming Technology and Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina China National Heavy machinery Research Institute Co. Ltd.Xi'an 710018ShaanxiChina Faculty of Mechanical Engineering Hebei University of ArchitectureZhangjiakou 075000HebeiChina

To overcome the inaccuracy problem of the traditional wedge evaluation of steel plates and strips caused by the ran-domness of the thicknesses of two local points and improve the reliability of the wedge index,the double-centroid method for the wedge evaluation was proposed,and a model based on the centroid theory was ***,an integral model for the discrete thickness values of the cross-section profiles was *** discussion focused on the distinct characteristics of the two-point method,asymmetric method,and double-centroid method in evaluating the asymmetric distribution of *** three methods were employed to evaluate the wedge values of both the theoretical and measured cross-sections of steel plates and strips,and the accuracies of three wedge evaluation models were analyzed and *** results showed that the double-centroid method objectively reflects the degree and variation characteristics of the wedge values of the cross-sections of steel plates and strips,and this method is feasible,reliable,and outstanding.

关键词： Steel plate and strip Wedge Two-point method Double-centroid method Reliability

Recent advances in Pt catalysts and membrane electrode assemblies fabrication for proton exchange membrane fuel cells

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Rare Metals 2024年第9期43卷 4198-4221页

作者： Miao ma Li-xiao Shen Jing Liu bin Xu Yun-Long Zhang Lei Zhao Zhen-Bo Wang School of Chemistry and Chemical Engineering Harbin Instituteof Technology College of Environmental and Chemical Engineering YanshanUniversity Unipower Hydrogen Technology (Jiangsu) Corporation

Proton exchange membrane fuel cells(PEMFCs) have been identified as a highly promising means of achieving sustainable energy conversion. A crucial factor in enhancing the performance of PEMFCs for further potential energy applications is the advancement in the field of catalyst engineering that has led to remarkable performance enhancement in facilitating the oxygen reduction reaction(ORR). Subsequently, it is important to acknowledge that the techniques used in preparation of membrane electrode assemblies(MEAs), the vital constituents of PEMFCs, also possess direct and critical influence on exhibiting the full catalytic activity of meticulously crafted catalysts. Here, a succinct summary of the most recent advancements in Pt catalysts for ORR was offered and their underly catalytic mechanism were discussed. Then, both laboratory-scale and industrial-scale MEA fabrication techniques of Pt catalysts were summarized. Furthermore, a detailed analysis of the connections between materials, process, and performance in MEA fabrication was presented in order to facilitate the development of optimal catalyst layers.

关键词： MEA fabrication techniques Membrane electrode assemblies Oxygen reduction reaction Pt catalysts

Enhanced piezoelectric performance of Cr/Ta non-equivalent co-doped Bi_(4)Ti_(3)O_(12)-based high-temperature piezoceramics

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Journal of Advanced Ceramics 2024年第3期13卷 263-271页

作者： Xuanyu Chen Ziqi ma bin Li Yejing Dai School of materials Sun Yat-sen UniversityShenzhen 518107China

In this study,(Cr_(1/3)/Ta_(2/3))non-equivalent co-doped Bi_(4)Ti_(3)O_(12)(BIT)ceramics were prepared to solve the problem that high piezoelectric performance,high Curie temperature,and high-temperature resistivity could not be achieved simultaneously in BIT-based ceramics.A series of Bi_(4)Ti_(3-x)(Cr_(1/3)Ta_(2/3))_(x)O_(12)(x=0-0.04)ceramics were synthesized by the solid-state reaction *** phase structure,microstructure,piezoelectric performance,and conductive mechanism of the samples were systematically *** B-site non-equivalent co-doping strategy combining high-valence Ta^(5+)and low-valence Cr^(3+)significantly enhances electrical properties due to a decrease in oxygen vacancy ***_(4)Ti_(2.97)(Cr_(1/3)Ta_(2/3))_(0.03)O_(12)ceramics exhibit a high piezoelectric coefficient(d_(33)=26 pC·N^(-1))and a high Curie temperature(TC=687℃).Moreover,the significantly increased resistivity(ρ=2.8×10^(6)Ω·cm at 500℃)and good piezoelectric stability up to 600℃are also obtained for this *** the results demonstrate that Cr/Ta co-doped BIT-based ceramics have great potential to be applied in high-temperature piezoelectric applications.

关键词： high temperature piezoelectricity co-doped Bi_(4)Ti_(3)O_(12)(BIT)

One-step construction of strongly coupled Co_(3)V_(2)O_(8)/Co_(3)O_(4)/MXene heterostructure via in-situ Co-F bonds for high performance all-solid-state asymmetric supercapacitors

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Rare Metals 2024年第2期43卷 682-691页

作者： Ji Zhou bin-bin Liu Hu Zheng Wen-Qing ma Qian Li Cai-Xia Xu Institute for Advanced Interdisciplinary Research(iAIR) Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of ShandongSchool of Chemistry and Chemical EngineeringUniversity of JinanJinan250022China

Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal *** interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and anchor on the surface of Ti_(3)C_(2)T_(x) via the strong Co-F bonds and contribute tremendously to depress Ti_(3)C_(2)T_(x) *** from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti_(3)C_(2)T_(x) as well as outstanding stability of the as-designed nanostructure,the optimum Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x)electrode reaches a commendable specific capacitance(up to 3800 mF·cm^(−2)),great rate capability(80%capacitance retention after 20-times current increasing),and preeminent cycling stability(95.4%/85.5%retention at 7000th/20,000th cycle).Moreover,the all-solid-state asymmetric supercapacitor based on Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) and active carbon can deliver a high energy density of 84.0μWh·cm^(−2) at the power energy of 3.2 mW·cm^(−2),and excellent cycling durability with 87.0%of initial capacitance retention upon 20,000 *** work provides a practicable pathway to tailor MXene-based composites for high-performance supercapacitor.

关键词： Ti_(3)C_(2)T_(x) Co_(3)V_(2)O_(8)/Co_(3)O_(4) Heterostructure Cathode Supercapacitor

Prognostic Significance of MiR-34a Expression in Patients with Gastric Cancer after Radical Gastrectomy

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Chinese Medical Journal 2015年第19期128卷 2632-2637页

作者： Wen.Tao Hui xiao-bin ma Ying Zan Xi-Jing Wang Lei Dong 1Department of Oncology The Second Affiliated Hospital Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710000 China Department of Gastroenterology The Second Affiliated Hospital Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710000 China

Background： MiR-34a dysregulation has been implicated in tumorigenesis and progression of gastric cancer, but its role in prognosis of patients with gastric cancer remains unknown. The aim of this study was to investigate the expression and prognostic significance of miR-34a in gastric cancer patients after radical gastrectomy. Methods： Quantitative real-time polymerase chain reaction was performed to detect the expression of miR-34a in human gastric cancer cell lines and tissues in 76 patients with gastric adenocarcinoma from China. Results are assessed for association with clinical features and overall survival （OS） using Kaplan-Meier analysis. Prognostic values of miR-34a expression and clinical outcomes were evaluated by Cox regression analysis. A molecular prognostic stratification scheme incorporating miR-34a expression was determined using receiver operating characteristic analysis. Results： The results show that the expression level of miR-34a was decreased in human gastric cancer cell lines and tissues, and down-regulated expression of miR-34a was associated with Lauren classification （P = 0.034）. Decreased miR-34a expression in gastric cancer tissues was positively correlated with poor OS of gastric cancer patients （P = 0.0 l 3）. Further multivariate Cox regression analysis suggested that miR-34a expression was an independent prognostic indicator for gastric cancer （P = 0.027）. Applying the prognostic value of miR-34a expression to tumor node metastasis （TNM） stage system showed a better prognostic value in patients with gastric cancer than miR-34a expression （P = 0.0435） or TNM stage （P = 0.0249） alone. Conclusion： The results reinforce the critical role for the down-regulated miR-34a expression in gastric cancer and suggest that miR-34a could be a prognostic indicator for this disease.

关键词： Gastric Cancer MiR-34a Overall Survival Prognostic Significance Radical Gastrectomy

Two-stage aging treatment to accelerate aging kinetics without impairing strength in B4C/7A04Al composite

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Science China Technological Sciences 2024年第8期67卷 2485-2492页

作者： CHEN YunTao ma GuoNan ZHU ShiZe WANG Dong xiao BoLv ma ZongYi Shi-Changxu Innovation Center for Advanced materials Institute of Metal Research Chinese Academy of Sciences School of materials Science and Engineering University of Science and Technology of China Centre of Excellence for Advanced materials

Aging treatments are the key process to obtain satisfactory strength for 7xxxAl alloys and their composites. However, traditional single-stage（SS） aging is time-consuming to reach a peak strength condition. In this study, an efficient 120℃ + 160℃ two-stage（TS） aging treatment was proposed on a B4C/7A04Al composite fabricated via powder metallurgy（PM） technology, which could acquire similar peak-aging strength but only took about 15% of the time compared to traditional 120℃ SS aging. The evolution of precipitation during the TS aging was investigated, as well as those of the 7A04Al alloys for comparison. In the second stage aging process, the higher aging temperature accelerated the nucleation of η′ phases inside the grains and thus increased the density of precipitates. Moreover, the short aging time limited the coarsening of precipitates and the broadening of precipitatefree zones. The above factors were beneficial for quickly obtaining satisfactory precipitation strengthening effects. The B4C/7A04Al composite exhibited slower aging kinetics than the 7A04Al alloy in the TS aging. Mg elements consumption by the chemical reaction between B impurities introduced by B4C particles and the Al matrix was considered to potentially retard the aging kinetics of the B4C/7A04Al composite. Nevertheless, the precipitation sequence was not affected.

关键词： aluminum matrix composites aging treatment powder metallurgy mechanical properties precipitation

Disastrous effects of climate change on High Mountain Asia

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Advances in Climate Change Research 2024年第3期15卷 365-366页

作者： Peng CUI Yao-Ming ma Yan WANG bin-binWANG Institute of Geographic Sciences and Natural Resources Research The Chinese Academy of Sciences(CAS)Beijing 100101China Institute of Mountain Hazards and Environment CASChengdu 610041China China-Pakistan Joint Research Center on Earth Sciences CAS-HECIslamabad 45320Pakistan State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchCASBeijing 100101China

High Mountain Asia(Hma),encompassing the Tibetan Plateau and the surrounding high mountain ranges of the Hindu Kush and Tianshan,is a region characterised by large terrain,complex topography and the interplay of vario... 详细信息

关键词： terrain Tianshan Tibetan