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Wear-resistant Ag-MAX phase 3D interpenetrating-phase composites:Processing,structure,and properties

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Nano Research 2024年第2期17卷 806-819页

作者： Yu Guo Xi Xie Zengqian Liu Longchao Zhuo Jian Zhang Shaogang Wang Qiqiang Duan Qing Jia Dake Xu weihai Xue Deli Duan Filippo Berto Zhefeng Zhang Rui Yang Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048China Electrobiomaterials institute Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education)Northeastern UniversityShenyang 110819China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China department of Chemical Engineering Materials and EnvironmentSapienza University of RomeRoma 00185Italy

Electrical contact materials are generally Ag-or Cu-based composites and play a critical role in ensuring the reliability and efficiency of electrical equipments and electronic *** MAX(M is an early transition metal,A is an element from III or IV main groups,and X is carbon or/and nitrogen)phase ceramics display a unique combination of properties and may serve as an ideal reinforcement phase for electrical contact *** biological materials evolved in nature generally exhibit three-dimensional(3D)interpenetrating-phase architectures,which may offer useful inspiration for the architectural design of electrical contact ***,a series of bi-continuous Ag-Ti_(3)SiC_(2) MAX phase composites with high ceramic contents exceeding 50 vol.%and having micron-and ultrafine-scaled 3D interpenetrating-phase architectures,wherein both constituents were continuous and mutually interspersed,were exploited by pressureless infiltration of Ag melt into partially sintered Ti_(3)SiC_(2) *** mechanical and electrical properties as well as the friction and wear performance of the composites were investigated and revealed to be closely dependent on the ceramic contents and characteristic structural *** composites exhibited a good combination of properties with high hardness over 2.3 GPa,high flexural strength exceeding 530 MPa,decent fracture toughness over 10 MPa·m^(1/2),and good wear resistance with low wear rate at an order of 10^(-5)mm^(3)/(N·m),which were much superior compared to the counterparts made by powder metallurgy *** particular,the hardness,electrical conductivity,strength,and fracture toughness of the composites demonstrated a simultaneous improvement as the structure was refined from micron-to ultrafine-scales at equivalent ceramic *** good combination of properties along with the facile processing route makes the Ag-Ti_(3)SiC_(2)3D interpenetrating-phase composites appealing for electrical contact applicatio

关键词： three-dimensional(3D)interpenetrating-phase architecture Ag-MAX(M=early transition metal A=element from III or IV main groups and X=carbon or/and nitrogen)phase composites melt infiltration electrical contact materials mechanical

Single-cell transcriptomic Atlas of aging macaque ocular outflow tissues

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Protein & Cell 2024年第8期15卷 594-611页

作者： Jian Wu Chaoye Wang Shuhui Sun Tianmin Ren Lijie Pan Hongyi Liu Simeng Hou Shen Wu Xuejing Yan Jingxue Zhang Xiaofang Zhao weihai Liu Sirui Zhu Shuwen Wei Chi Zhang Xu Jia Qi Zhang Ziyu Yu Yehong Zhuo Qi Zhao Chenlong Yang Ningli Wang Beijing institute of Ophthalmology Beijing Tongren Eye CenterBeijing Tongren HospitalCapital Medical UniversityBeijing Key Laboratory of Ophthalmology and Visual SciencesBeijing 100730China State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-sen UniversityGuangzhou 510060China State Key Laboratory of Oncology in South china Collaborative Innovation Center for Cancer MedicineSun Yat-sen University Cancer CenterGuangzhou 510060China State Key Laboratory of Membrane Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Beijing institute for Stem Cell and Regenerative Medicine Beijing 100101China institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China department of Neurosurgery Peking University Third HospitalCenter for Precision Neurosurgery and Oncology of Peking University Health Science CenterBeijing 100191China Spencer Center for Vision Research Byers Eye InstituteSchool of MedicineStanford UniversityPalo AltoCA 94304USA

The progressive degradation in the trabecular meshwork(TM)is related to age-related ocular diseases like primary open-angle ***,the molecular basis and biological significance of the aging process in TM have not been fully ***,we established a dynamic single-cell transcriptomic landscape of aged macaque TM,wherein we classified the outflow tissue into 12 cell subtypes and identified mitochondrial dysfunction as a prominent feature of TM ***,we divided TM cells into 13 clusters and performed an in-depth analysis on cluster O,which had the highest aging score and the most significant changes in cell proportions between the two ***,we found that the APOE gene was an important differentially expressed gene in cluster O during the aging process,highlighting the close relationship between cell migration and extracellular matrix regulation,and TM *** work further demonstrated that silencing the APOE gene could increase migration and reduce apoptosis by releasing the inhibition on the PI3K-AKT pathway and downregulating the expression of extracellular matrix components,thereby increasing the aqueous outflow rate and maintaining intraocular pressure within the normal *** work provides valuable insights for future clinical diagnosis and treatment of glaucoma.

关键词： single-cell transcriptomic atlas macaque trabecular meshwork ocular outflow tissue aging

Catalysts for decomposing ozone tail gas

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Journal of Environmental sciences 2003年第6期15卷 779-782页

作者： LIU Chang-an, SUN De-zhi, WANG Hui, LI Wei (department of Environmental Science and Engineering, harbin institute of technology, harbin 150001,china. department of Environmental Science and Engineering Harbin Institute of Technology Harbin 150001 China

The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially, and their catalytic activities were investigated. The results showed that the catalyst with activated carbon dipping acetate(active components are Mn:Cu=3:2, active component proportion in catalyst is 15%, calcination temperature is 200℃) has the best catalytic activity for ozone decomposing. One gram of catalyst can decompose 17.6 g ozone at initial ozone concentration of 2.5 g/m 3 and the residence time in reactor of 0.1 s. The experimental results also indicated that humidity of reaction system had negative effect on catalytic activity.

关键词： ozone tail gas catalytic decomposition immobilizing-catalyst MnO 2 CuO

Weighted norm inequalities for the multilinear Calderón-Zygmund operators

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Science china Mathematics 2010年第7期53卷 1859-1872页

作者： HU GuoEn department of Applied Mathematics, Zhengzhou Information sciences and technology institute,Zhengzhou 450002, china department of Applied Mathematics Zhengzhou Information Sciences and Technology Institute Zhengzhou China

In this paper, by proving some suitable weighted endpoint estimates, and then by multilinear interpolation and a new multilinear extrapolation lemma, the author establishes some weighted estimates for the multilinear ... 详细信息

关键词： multilinear Calderón-Zygmund operator commutator weighted norm inequality interpolation extrapolation

Protective effects of L-arginine on pulmonary oxidative stress and antioxidant defenses during exhaustive exercise in rats

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Acta Pharmacologica Sinica 2005年第8期26卷 992-999页

作者： Wan-teng LIN~(2,5), Suh-ching YANG~3, Kung-tung CHEN~4, Chi-chang HUANG~3, Ning-yuean LEE~(2,6) ~2 department of Nutrition and food sciences, Fu-Jen Catholic University, Taipei, china ~3 School of Nutrition and Health sciences, Taipei Medical University, Taipei, china ~4 department of General Education, Ming Hsin University of Science and technology Hsinchu, china ~5 De Lin institute of technology, Taipei, china department of Nutrition and food sciences Fu-Jen Catholic University Taipei China De Lin institute of technology Taipei China School of Nutrition and Health sciences Taipei Medical University Taipei China department of General Education Ming Hsin University of Science and Technology Hsinchu China

Aim: To assess the effects of L-arginine (L-Arg) supplementation on pulmonary oxidative stress and antioxidant defenses in rats after exhaustive exercise. Methods: Rats were randomly divided into four groups: sedentary control (SC), sedentary control with L-Arg treatment (SC+Arg), exhaustive exercise with control diet (E) and exhaustive exercise with L-Arg treatment (E+Arg). Rats in groups SC+Arg and E+Arg received a 2% L-Arg diet. Rats in groups E and E+Arg underwent an exhaustive running test on a motorized treadmill. Pulmonary oxidative stress indices [xanthine oxidase (XO), myeloperoxidase (MPO), and malondialdehyde (MDA)] and antioxidant defense systems [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione (GSH)] were investigated in this study. Results: L-Arg supplementation significantly reduced exercise-induced elevations of XO and MPO activities in lung. LArg reversed the exercise-induced increase in SOD and GR activities, but increased CAT and GPX activities. L-Arg administration also significantly increased the GSH levels in plasma. Conclusion: L-Arg supplementation can prevent elevations of XO and MPO activities in the lung and favorably influence pulmonary antioxidant defense systems after exhaustive exercise.

关键词： L-arginine oxidative stress xanthine oxidase myeloperoxidase exhaustive exercise lung

Fiducial intervals of restricted parameters and their applications

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Science china Mathematics 2005年第11期48卷 1567-1583页

作者： LI Xinmin, LI Guoying & XU Xingzhong College of Mathematics and Information sciences, Shandong University of technology, Zibo 255049, china Academy of Mathematics and System sciences, Chinese Academy of sciences, Beijing 100800, china department of Mathematics, Beijing institute of technology, Beijing 100801, china College of Mathematics and Information sciences Shandong University of Technology Zibo China Academy of Mathematics and System sciences Chinese Academy of Sciences Beijing China department of Mathematics Beijing Institute of Technology Beijing China

In practice, the unknown parameters are often restricted. This paper provides a general method for constructing the fiducial intervals of the restricted parameters. Applying the general method, the fiducial intervals are constructed for the location (scale)parameters and the difference (ratio) of two locations (scales) in a location (scale) family of distributions. The frequency properties of these intervals are verified. For a variance components model, the fiducial intervals for the three parameters of common interest are obtained. Their frequency properties are investigated theoretically and computationally.

关键词： restricted parameter space,fiducial interval,frequency property,variance components

One-step estimation for varying coefficient models

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Science china Mathematics 2005年第2期48卷 198-213页

作者： TANG Qingguo & WANG Jinde department of Mathematics, Nanjing University, Nanjing 210093, china institute of sciences, PLA University of Science and technology, Nanjing 210007, china department of Mathematics Nanjing University Nanjing China institute of sciences PLA University of Science and Technology Nanjing China

A one-step method is proposed to estimate the unknown functions in the varying coefficient models, in which the unknown functions admit different degrees of smoothness. In this method polynomials of different orders are used to approximate unknown functions with different degrees of smoothness. As only one minimization operation is employed, the required computation burden is much less than that required by the existing two-step estimation method. It is shown that the one-step estimators also achieve the optimal convergence rate. Moreover this property is obtained under conditions milder than that imposed in the two-step estimation method. More importantly, as only one minimization operation is employed, the full asymptotic properties, not only the asymptotic bias and variance, but also the asymptotic distributions of the estimators can be derived. The asymptotic distribution results will play a key role for making statistical inference.

关键词： varying coefficient model, one-step estimation, asymptotic distribution, optimal convergence rate.

Study on New Sensitive Method of Determination of Phosphorus by Solid Phase Spectrophotometry

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Chinese Chemical Letters 2000年第7期11卷 609-612页

作者： Yue Qin XEI Shao Min LIU Hong Wu TONG Ya DAI(department of Chemistry, Anhui institute of Education, Hefei 230061 department of food Science, institute of Economics and technology, University of Science and technology of china, Hefei 230052) department of Chemistry Anhui Institute of Education Hefei 230061 China department of food Science Inst. of Economics and Technology Univ. of Sci. and Technol. of China Hefei 230052 China

The use of solid phase spectrophotometry for the determination of trace phosphorus in the system of phosphomolybdate-fructose is described. The adsorption of the system on anion-exchange resin is reported.

关键词： phosphorus solid phase spectrophotometry anion-exchanger resin adsorption

On the stability of diffusion processes with state-dependent switching

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Science china Mathematics 2006年第9期49卷 1258-1274页

作者： XI Fubao & ZHAO Liqin department of Mathematics, Beijing institute of technology, Beijing 100081, china School of Mathematical sciences, Beijing Normal University, Beijing 100875, china department of Mathematics Beijing Institute of Technology Beijing China School of Mathematical sciences Beijing Normal University Beijing China

In this paper we consider the stability for diffusion processes with state-dependent switching. We first prove their Feller continuity by the coupling methods. Furthermore, we also prove their strong Feller continuity and their exponential ergodicity under some reasonable conditions. Finally, we append a very brief discussion about the regularity of these processes.

关键词： Feller continuity, coupling, strong Feller continuity, exponential ergodicity,state-dependent switching.