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Friction 2024年第3期12卷 452-461页

作者： Xiaoyue wang Zenghui YANG Tingmei wang qihua wang Xinrui ZHANG Song LI Key Laboratory of Science and Technology on Wear and Protection of Materials Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Recyclability of thermosetting polymers and their composites is a challenge for alleviating environmental pollution and resource *** this study,solvent-recyclable thermosetting polyimide(PI)and its composite were successfully *** tensile strength,elongation at break,and Young’s modulus of PI are 108.70±7.29 MPa,19.35%±3.89%,and 2336.42±128.00 MPa,*** addition of reduced graphene oxide(RGO)not only enhances the mechanical properties of PI but also endows it with excellent tribological *** PI illustrates a high recycling efficiency of 94.15%,but the recycled composite exhibits inferior mechanical *** recycling and utilization of PI and its composite are realized through imine bonds(-C=N),which provides new guidance for solving the problem of environmental pollution and resource waste and is potential application in the field of sustainable tribology.

关键词： thermosetting polyimide(PI) recyclability dynamic covalent bonds friction and wear polymer composites

Tribological properties of PTFE-based fabric composites at cryogenic temperature

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Friction 2024年第2期12卷 245-257页

作者： Mingkun XU Zidan wang Lihe GUO Liming TAO Tianbao MA Tingmei wang qihua wang Key Laboratory of Science and Technology on Wear and Protection of Materials Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Fabric composites are widely employed in self-lubricating bearing liners as solid lubrication *** the tribological behaviors of fabric composites have been extensively studied,the cryogenic tribological properties and mechanisms have been scarcely reported and are largely unclear to instruct material design for aerospace and other high-tech ***,the tribological properties of polytetrafluoroethylene(PTFE)-based hybrid-fabric composites were investigated at cryogenic and ambient temperatures in the form of pin-on-disk friction under heavy *** results suggest that the friction coefficients of the hybrid-fabric composites obviously increase with a decrease in wear when the temperature drops from 25 to−150°***,thermoplastic polyetherimide(PEI),as an adhesive for fabric composites,has better cryogenic lubrication performance than thermosetting phenol formaldehyde(PF)resin,which can be attributed to the flexible chemical structure of *** excellent lubrication performance of hybrid-fabric composites is attributed to the transfer film formed by PTFE fibers on the surface of fabrics.

关键词： cryogenic temperatures fabric composites friction and wear transfer film

聚六氢化三嗪交联聚酰亚胺/石墨烯形状记忆复合材料

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功能高分子学报 2024年第2期37卷 113-120页

作者：杨增辉王炎张新瑞王廷梅王齐华中国科学院兰州化学物理研究所兰州730000

以高分散性的氧化石墨烯(GO)作为增强相,通过溶剂挥发、高温环化的方法制备了聚六氢化三嗪交联聚酰亚胺/石墨烯(PI-PHT)形状记忆复合材料。利用核磁、红外光谱、热重分析等对材料的结构和热稳定性进行表征,通过万能试验机对复合材料的... 详细信息

以高分散性的氧化石墨烯(GO)作为增强相,通过溶剂挥发、高温环化的方法制备了聚六氢化三嗪交联聚酰亚胺/石墨烯(PI-PHT)形状记忆复合材料。利用核磁、红外光谱、热重分析等对材料的结构和热稳定性进行表征,通过万能试验机对复合材料的力学性能进行测试,通过动态热机械分析仪对热机械性能、形状记忆性能、形状回复力等进行分析。结果表明:引入石墨烯后,复合材料的强度、韧性、热机械性能以及形状记忆性能明显提升,其中当GO的质量分数为5%时,复合材料的拉伸强度和韧性分别达到105.7 MPa和12.4 MJ/m~3(相比未添加GO的PI-PHT分别提高了1.3倍和2倍),并且其形状固定率、回复率和回复应力分别达到了97.2%、92.6%和9.46 MPa。

关键词：聚酰亚胺形状记忆石墨烯聚六氢化三嗪力学性能

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Functional singular component analysis based functional additive models

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Science China Mathematics 2016年第12期59卷 2443-2462页

作者： ZHANG Tao wang qihua School of Science Guangxi University of Science and Technology Academy of Mathematics and Systems Science Chinese Academy of Sciences Institute of Statistical Science Shenzhen University

We propose a method which uses functional singular component to establish functional additive models. The proposed methodology reduces the curve regression problem to ordinary(i.e., scalar) additive regression problems of the singular components of the predictor process and response process. Consistency of estimators for the nonparametric function and prediction are proved, respectively. A simulation study is conducted to investigate the finite sample performances of the proposed estimators.

关键词： functional data functional additive models functional singular component analysis

Probability density estimation with surrogate data and validation sample

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Frontiers of Mathematics in China 2013年第3期8卷 665-694页

作者： qihua wang Wenquan CUI Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China Department of Statistics and Finance University of Science and Technology of China Hefei 230026. China

The probability density estimation problem with surrogate data and validation sample is considered. A regression calibration kernel density estimator is defined to incorporate the information contained in both surrogate variates and validation sample. Also, we define two weighted estimators which have less asymptotic variances but have bigger biases than the regression calibration kernel density estimator. All the proposed estimators are proved to be asymptotically normal. And the asymptotic representations for the mean squared error and mean integrated square error of the proposed estimators are established, respectively. A simulation study is conducted to compare the finite sample behaviors of the proposed estimators.

关键词： Measurement error asymptotic normality convergent rate

Empirical likelihood-based dimension reduction inference for linear error-in-responses models with validation study

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Science China Mathematics 2004年第6期47卷 921-939页

作者： wang qihua Hardie Wolfgang Academy of Mathematics and System Sciences Chinese Academy of SciencesBeijing 100080China Heilongjiang University Harbin 150080China Center for Applied Statistics and Economics Humboldt-Universitat zu Berlin10178 BerlinGermany

In this paper, linear errors-in-response models are considered in the presence of validation data on the responses. A semiparametric dimension reduction technique is employed to define an estimator of β with asymptotic normality, the estimated empirical loglikelihoods and the adjusted empirical loglikelihoods for the vector of regression coefficients and linear combinations of the regression coefficients, respectively. The estimated empirical log-likelihoods are shown to be asymptotically distributed as weighted sums of independent X 2 1 and the adjusted empirical loglikelihoods are proved to be asymptotically distributed as standard chi-squares, respectively.

关键词： confidence intervals error-in-response validation data

焦虑对白内障术后患者的干眼症状及生活质量的影响

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国际精神病学杂志 2024年第4期51卷 1251-1253页

作者：张豪王其华空军军医大学第一附属医院眼科西安710032

目的探讨焦虑对白内障术后患者的干眼症状及生活质量的影响。方法本研究对象为2021年2月~2022年12月97例白内障患者,术后进行焦虑情绪评价,并根据评价结果设为焦虑组以及无焦虑组。术后1周评估汉密尔顿焦虑量表(HAMA),干眼主观症状及体... 详细信息

目的探讨焦虑对白内障术后患者的干眼症状及生活质量的影响。方法本研究对象为2021年2月~2022年12月97例白内障患者,术后进行焦虑情绪评价,并根据评价结果设为焦虑组以及无焦虑组。术后1周评估汉密尔顿焦虑量表(HAMA),干眼主观症状及体征评分,视功能评分(VF)以及过中国版视功能指数量表(VF-14-CN),并分析焦虑组HAMA评分与上述指标的相关性。结果97例白内障患者术后检出焦虑28例;焦虑组干眼主观评分显著高于无焦虑组,泪膜破裂时间(BUT),泪液分泌试验显著低于无焦虑组,(P<0.05);焦虑组VF评分,VF-14-CN评分显著低于无焦虑组,(P<0.05);焦虑组HAMA评分与干眼主观评分呈正相关,与BUT,泪液分泌试验,VF评分,VF-14-CN评分呈负相关,(P<0.05)。结论白内障术后焦虑情况较为常见,焦虑可能加重白内障术后干眼症状,并降低视功能以及视觉相关生活质量。

关键词：焦虑白内障术后干眼症生活质量

Design and optimization of an integrated process for the purification of propylene oxide and the separation of propylene glycol by-product

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Chinese Journal of Chemical Engineering 2022年第5期35卷 111-120页

作者： Song Hu Jinlong Li qihua wang Weisheng Yang State Key Laboratory of Green Chemical Engineering and Industrial Catalysis SINOPEC Shanghai Research Institute of petrochemical TechnologyShanghai 201208China School of Petrochemical Engineering Changzhou UniversityChangzhou 213164China

It is difficult to separate the methanol and hydrocarbons in the propylene oxide(PO)purification process due to their forming *** for this,a novel PO separation process,in that the deionized water is employed as extractant and 1,2-propylene glycol(MPG)that is formed from the PO hydrolysis reaction is recovered,is presented in this *** salient feature of this process is that both the non-catalyzed reactions of PO hydrolysis to form MPG and dipropylene glycol(DPG)are simultaneously considered and MPG by-product with high purity is obtained in virtue of the deionized water as reflux liquid and side take-off in MPG *** addition,the ionic liquid(IL)extractant is screened through the conductorlike screening model for segment activity coefficient(COSMO-SAC)and the comparisons of separation efficiency between the IL and normal octane(nC_(8))extractant for the separation of PO and 2-methylpentane are *** the non-random two-liquid(NRTL)thermodynamic model,the simulation and optimization design for the full flow sheet are performed and the effects of the key operation parameters such as solvent ratio,theoretical stages,feeding stage *** separation efficiency are detailedly *** results show that the mass purity and the mass yield of PO can be up to 99.99%and 99.0%,and the condenser duty,reboiler duty and PO loss in the process with IL extractant can be decreased by 69.66%,30.21%and 78.86%compared to ones with nC_(8).The total annual cost(TAC)calculation also suggests that the TAC would be significantly reduced if using IL in replace of nC_(8) for the investigated *** presented results would provide a useful guide for improving the quality of PO product and the economic efficiency of industrial plant.

关键词： Propylene oxide purification Ionic liquids Separation Extractive distillation Hydrolysis 1 2-propylene glycol

Finite sample breakdown point of Tukey＇s halfspace median

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Science China Mathematics 2017年第5期60卷 861-874页

作者： LIU XiaoHui ZUO YiJuna wang qihua School of Statistics Jiangxi University of Finance and Economics Nanchang 330013 China Research Center of Applied Statistics Jiangxi University of Finance and Economics Nanchang 330013 China Department of Statistics and Probability Michigan State University East Lansing MI 48823 USA Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China Institute of Statistical Science Shenzhen University Shenzhen 518006 China

Tukey's halfspace median(HM), servicing as the multivariate counterpart of the univariate median,has been introduced and extensively studied in the literature. It is supposed and expected to preserve robustness property(the most outstanding property) of the univariate median. One of prevalent quantitative assessments of robustness is finite sample breakdown point(FSBP). Indeed, the FSBP of many multivariate medians have been identified, except for the most prevailing one—the Tukey's halfspace median. This paper presents a precise result on FSBP for Tukey's halfspace median. The result here depicts the complete prospect of the global robustness of HM in the finite sample practical scenario, revealing the dimension effect on the breakdown point robustness and complimenting the existing asymptotic breakdown point result.

关键词： Tukey depth Tukey median breakdown point in general position

Iinnc Crehaisninag the international influence of Science in China

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Science China Mathematics 2009年第6期52卷 1081-1082页

作者： wang qihua Chinese Acad Sci Acad Math & Syst Sci Beijing 100864 Peoples R China

Science in China Series A: Mathematics, a peer-reviewed academic journal, covers novel and important research results in basic and applied mathematics, providing a forum for

关键词： Iinnc Crehaisninag the international influence of Science in China