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Deformation and damage features of a Re/Ru-containing single crystal nickel base superalloy during creep at elevated temperature

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Progress in Natural Science:Materials International 2019年第2期29卷 210-216页

作者： Guoqi Zhao Sugui tian Shunke Zhang ning tian Lirong Liu School of Mechanical Engineering Guizhou University of Engineering Science School of Materials Science and Engineering Shenyang University of Technology

The deformation and damage features of a 4.5%Re/3.0%Ru-containing single crystal nickel-based superalloy during the creep in the temperature range of 1040–1070 °C and stress range of 137–180 MPa was investigated by means of creep properties measurement and contrast analysis of dislocation configuration. The results showed that the alloy exhibited a better creep resistance in the range of the testing temperatures and stresses, the deformation mechanism of the alloy during steady state creep was dislocations climbing over the rafted γ′ *** the latter period of creep, the deformation mechanism of the alloy was dislocations shearing into the rafted γ′phase. It is believed that the dislocations shearing into γ′ phase may cross-slip from {111} to {100} planes for forming the K-W locks to restrain the slipping and cross-slipping of dislocations on {111} plane. As the creep goes on, the alternate slipping of dislocations results in the twisted of the rafted γ′ phase to promote the initiation and propagation of cracks along the γ/γ′ interfaces up to creep fracture, which is considered to be the damage and fracture feature of alloy during creep at high temperature.

关键词： Re/Ru alloying Single crystal nickel-based superalloy Creep Dislocations climbing K-W locks

Synthesis of covalent organic framework materials and their application in the field of sensing

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Nano Research 2024年第1期17卷 162-195页

作者： Weiyu Zhang Shiwei Liu Qihua Sun ning tian Zhaofeng Wu Xinjiang Key Laboratory of Solid-State Physics and Devices Urumqi 830046China School of Physics Science and Technology Xinjiang UniversityUrumqi 830046China

Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building *** to their large surface area,high intrinsic pore space,good crystallization properties,high stability,and designability of the resultant units,COFs are widely studied and used in the fields of gas adsorption,drug transport,energy storage,photoelectric catalysis,electrochemistry,and *** recent years,the rapid development of the Internet of Things and people’s yearning for a better life have put forward higher and more requirements for sensors,which are the core components of the Internet of ***,this paper reviews the recent progress of COFs in synthesis methods and sensing applications,especially in the last five *** paper first introduces structure,properties,and synthesis methods of COFs and discusses advantages and disadvantages of different synthesis ***,the research progress of COFs in different sensing fields,such as metal ion sensors,gas sensors,biomedical sensors,humidity sensors,and pH sensors,is introduced *** and prospects are also presented in order to provide a reference for researchers concerned with COFs and sensors.

关键词： covalent organic framework materials structural design and synthesis sensing application gas sensors

Cause analysis and reoperation effect of failure and recurrence after epiblepharon correction in children

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World Journal of Clinical Cases 2020年第24期8卷 6274-6281页

作者： Yue Wang Yang Zhang ning tian Department of Ophthalmology Beijing Tongren Eye CenterBeijing Tongren Hospital of Capital Medical UniversityBeijing Key Laboratory of Ophthalmology and Visual ScienceBeijing 100730China

BACKGROUND In children, it is common to see failure and recurrence in the correction ofepiblepharon and to have reoperation due to obvious irritation symptoms andcorneal *** To explore the causes of failure and recurrence after epiblepharon correction inchildren, to remove accurately redundant epiblepharon and orbicularis oculimuscle in patients via the cilia-everting suture technique combined with lidmargin splitting in some patients due to inverted lashes in the medial part of theeyelid, and to observe the therapeutic *** From 2015 to 2019, in the Outpatient Department of Ophthalmology of BeijingTongren Hospital, 22 children (40 eyes) with epiblepharon, aged 5-12 years, weretreated due to correction failure and recurrence. Fourteen patients (28 eyes)underwent the full-thickness everting suture technique, and eight patients (16eyes) underwent incisional surgery. They were treated by reviewing the previoussurgical methods and observing epiblepharon, eyelash direction, and cornealinjury. During reoperation, a subciliary incision was made 1 mm below theinferior lash line. Incisional surgery for the lower eyelid was used to removeaccurately redundant epiblepharon and part of the pretarsal orbicularis *** tissue and the orbicularis muscle of the upper skin-muscle flapwere anchored to the anterior fascia of the tarsal plate by rotational sutures. Lidmargin splitting was used only for patients who had seriously inverted lasheslocated in the medial part of the eyelid. All patients were followed for 6-12 moafter reoperation to observe the lower eyelid position, skin incision, eyelash direction, corneal damage, and *** After reoperation, all the patients were corrected. Photophobia, rubbing the eye,winking, and tearing disappeared. There was no lower eyelid entropion,ectropion, or retraction. There was no obvious sunken scar or lower eyelid *** eyelashes were far away from the cornea, and when the patients lookeddown, t

关键词： Epiblepharon failure recurrence Children Reoperation effect Epiblepharon correction Irritation symptom

Microstructure heterogeneity and creep damage of DZ125 nickel-based superalloy

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Progress in Natural Science:Materials International 2014年第3期24卷 266-273页

作者： Haofang Sun Sugui tian ning tian Huichen Yu Xianlin Meng School of Materials Science and Engineering Shenyang University of Technology Beijing Institute of Aeronautical Materials

The creep behavior of the DZ125 superalloy at high temperatures has been investigated based on the creep properties measurement and microstructure observations. The experimental results show that, after full heat treatment, the fine and coarser cuboidal γ0precipitates distributed in the dendrite arm and inter-dendrite regions, respectively, the boundaries with various configurations located in the inter-dendrite regions. In the primary creep stage, the cuboidal γ0phase in the alloy transformed into the rafted structure along the direction vertical to the stress *** dislocations slipping and climbing over the rafted γ0phase are attributed the deformation mechanism of the alloy during steady-state ***(1/2)?1 1 0? dislocations slipping in the γ matrix and ?1 1 0? super-dislocations shearing into the γ0phase are the deformation mechanisms of the alloy in the latter stage of creep. And then the alternate slipping of dislocations results in the initiation and propagation of the micro-cracks along the boundaries until the occurrence of the creep fracture. Since the grain boundaries with various angles relative to the stress axis distribute in the different regions, the initiation and propagation of micro-cracks along the boundaries display the various features.& 2014 Chinese Materials Research Society. Production and hosting by Elsevier B.V. All rights reserved.

关键词： DZ125 nickel-based superalloy Microstructure Creep mechanism

Fast response ultraviolet photodetectors based on solution-processed ZnO nanocrystals

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Science China(Technological Sciences) 2015年第8期58卷 1328-1332页

作者： ZHANG TongShuo YU Ji DENG YuFu tian ning GAO Peng College of Physics Science and Technology Shenyang Normal University

By utilizing Schottky contact in device fabrication,we have constructed fast response ultraviolet photodetectors based on the solution-processed Zn O *** 5 V,the detector exhibits fast photoresponse with a rise time of 20 ns and fall time of 350 ns,which is one of the fastest response time among the reported Zn O-based *** results reported in this paper may show great promise for fast response optoelectronic devices based on the solution-processed nanocrystals.

关键词： ultraviolet photodetector solution-processed nanocrystal ZnO fast response

Hole transport and phonon scattering in epitaxial PbSe films

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 137-142页

作者： Jian-xiao SI Hui-zhen WU tian-ning XU Chun-fang CAO Department of Physics Zhejiang University Hangzhou 310027 China College of Physics and Mathematics Zhejiang Normal University Jinhua 321004 China

The combined characterizations of mobility and phonon scattering spectra allow us to probe hole transport process in epitaxial PbSe crystalline films grown by molecular beam epitaxy (MBE). The measurements of Hall effect show p-type con- ductivity of PbSe epitaxial films. At 295 K, the PbSe samples display hole concentrations of (5～8)×1017 cm–3 with mobilities of about 300 cm2/(V·s), and at 77 K the hole mobility is as high as 3×103 cm2/(V·s). Five scattering mechanisms limiting hole mobilities are theoretically analyzed. The calculations and Raman scattering measurements show that, in the temperatures between 200 and 295 K, the scattering of polar optical phonon modes dominates the impact on the observed hole mobility in the epitaxial PbSe films. Raman spectra characterization observed strong optical phonon scatterings at high temperature in the PbSe epitaxial films, which is consistent with the result of the measured hole mobility.

关键词： Electrical properties of PbSe Mobility Scattering mechanism

Mechanism of the reconstruction of aqueous outflow drainage

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Science China(Life Sciences) 2018年第5期61卷 534-540页

作者： Chen Xin ning tian Meng Li Huaizhou Wang ningli Wang Beijing Institute of Ophthalmology Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology & Visual Sciences Key Laboratory Beijing 100005 China Department of ophthalmology Beo'ing Anzhen Hospital Capital Medical University Beijing 100029 China

Glaucoma is the leading cause of irreversible blindness worldwide. The reconstruction of aqueous outflow drainage (RAOD) has recently been proposed to aid in restoring aqueous outflow drainage in primary open-angle glaucoma. However, the mechanism of RAOD remains to be fully understood. Based on literature review and research studies, the potential mechanisms of RAOD are the following: (i) Circumferential dilation of the Schlemm’s canal (SC) and surrounding collector channels. (ii) Instant formation of microcracks through RAOD procedures. (iii) Formation of more pores, and local detachment between the SC endothelium (SCE) and basement membrane. (iv) Activation of stem cells by constant mechanical stress caused by the tensional suture placed at the anterior part of the SC. (v) Reversal of trabecular meshwork (TM) herniation. (vi) Mobilization of the reserve of the aqueous drainage. (vii) Change of SCE phenotype. (viii) Mechanosensing and mechanotransducing of TM.

关键词： reconstruction of aqueous outflow drainage canaloplasty Schlemm'scanal trabecular meshwork

Nonlinear Bayesian Estimation： From Kalman Filtering to a Broader Horizon

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IEEE/CAA Journal of Automatica Sinica 2018年第2期5卷 401-417页

作者： Huazhen Fang ning tian Yebin Wang Meng Chu Zhou Mulugeta A. Haile IEEE Department of Mechanical Engineering University of Kansas Lawrence KS 66045 USA Mitsubishi Electric Research Laboratories Cambridge MA 02139 USA the Helen and John C. Hartmann Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ 07102 USA the Vehicle Technology Directorate US Army Research Laboratory Aberdeen MD 21005 USA

This article presents an up-to-date tutorial review of nonlinear Bayesian estimation. State estimation for nonlinear systems has been a challenge encountered in a wide range of engineering fields, attracting decades of research effort. To date,one of the most promising and popular approaches is to view and address the problem from a Bayesian probabilistic perspective,which enables estimation of the unknown state variables by tracking their probabilistic distribution or statistics(e.g., mean and covariance) conditioned on a system's measurement *** article offers a systematic introduction to the Bayesian state estimation framework and reviews various Kalman filtering(KF)techniques, progressively from the standard KF for linear systems to extended KF, unscented KF and ensemble KF for nonlinear systems. It also overviews other prominent or emerging Bayesian estimation methods including Gaussian filtering, Gaussian-sum filtering, particle filtering and moving horizon estimation and extends the discussion of state estimation to more complicated problems such as simultaneous state and parameter/input estimation.

关键词： Index Terms-Kalman filtering (KF) nonlinear Bayesian esti-mation state estimation stochastic estimation.

Nonlinear Optical Properties of D-π-A-π-D Type Oligomers with Different Conjugation Length

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Chinese Journal of Chemical Physics 2015年第5期28卷 -页

作者： tian-hao Huang Ying-hui Wang tian-ning Xu Feng-ying Yu Han-zhuang Zhang Yu-ran Wang Department of Science Zhijiang College of Zhejiang University of Technology Hangzhou 310024ChinaFemtosecond Laboratory College of Physics Jilin University Changchun 130012 China Femtosecond Laboratory College of Physics Jilin University Changchun 130012 China Department of Science Zhijiang College of Zhejiang University of Technology Hangzhou 310024China North China University of Science and Technology Tangshan 063000 China

The conjugation length-dependent nonlinear optical properties of fluorenone-based linear conjugated oligomers have been investigated by experimental and theoretical methods. Infrared spectra and the steady-state absorption spectra show that the increase of conjugated unit could enhance the stretching vibration peaks of C=C and lead to a red-shift of the absorption peaks. Meanwhile, the two-photonfluorescence (TPF) intensity is gradually enhanced with the increase of excitation energy, and the TPF efficiency is obviously higher after the introduction of fluorene-ethylene units. The sum-over-states approach was used to model the two-photon absorption (TPA) cross-sections of oligomers, and the theoretical values agree well with the experimental data obtained from the femtosecond open-aperture z-scan technique. The results exhibit that the extension of conjugated system indeed plays a role in the improvement of TPA behavior of oligomers.

关键词： Linear conjugated oligomer Two-photo absorption Sum-over-states