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Tuning the crystallite size of monoclinic ZrO_(2) to reveal critical roles of Surface defects on m–ZrO_(2) catalyst for direct synthesis of isobutene from syngas

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Chinese Journal of Chemical Engineering 2021年第7期34卷 211-219页

作者： Xuemei Wu Minghui Tan Bing Xu Shengying Zhao Qingxiang Ma Yingluo He Chunyang Zeng Guohui Yang Noritatsu Tsubaki Yisheng Tan State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan 750021China Department of Applied Chemistry School of EngineeringUniversity of ToyamaGofuku 3190Toyama 930-8555Japan China Petroleum Chemical Industry Federation Beijing 100723China

The effects of crystallite size on the physicochemical properties and Surface defects of pure monoclinic ZrO_(2) catalysts for isobutene synthesis were studied.We prepared a series of monoclinic ZrO_(2) catalysts with different crystallite size by changing calcination temperature and evaluated their catalytic performance for isobutene synthesis from syngas.ZrO_(2) with small crystalline size showed higher CO conversion and isobutene selectivity,while samples with large crystalline size preferred to form dimethyl ether(DME)instead of hydrocarbons,much less to isobutene.Oxygen defects(Odefects)analyzed by X-ray photoelectron spectroscopy(XPS)provided evidence that more Odefectsoccupied on the surface of ZrO_(2) catalysts with smaller crystalline size.Electron paramagnetic resonance(EPR)and ultraviolet–visible diffuse reflectance(UV–vis DRS)confirmed the presence of high concentration of Surface defects and Zr3+on mZrO_(2)-5.9 sample,respectively.In situ diffuse reflectance infrared Fourier transform spectroscopy(in situ DRIFTS)analysis indicated that the adsorption strength of formed formate species on catalyst reduced as the crystalline size decreased.These results suggested that Surface defects were responsible for CO activation and further influenced the adsorption strength of surface species,and thus the products distribution changed.This study provides an in-depth insight for active sites regulation of ZrO_(2) catalyst in CO hydrogenation reaction.

关键词： Syngas Isobutene ZrO_(2)catalyst Crystallite size Surface defects

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Impact of Methanol Photomediated Surface defects on Photocatalytic H2 Production Over Pt/TiO2

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Energy & Environmental Materials 2020年第2期3卷 202-208页

作者： Zhi Jiang Rongjie Qi Zhengwen Huang Wenfeng Shanggguan Roong Jien Wong Adam Lee Research Center for Combustion and Environment Technology Shanghai Jiao Tong UniversityShanghai 200240China Center of Hydrogen Science Shanghai Jiao Tong UniversityShanghai 200240China School of Science RMIT UniversityMelbourne Vic.3000Australia

Co-catalysts play a critical role in enhancing the efficiency of inorganic semiconductor photocatalysts;however,synthetic approaches to tailoring cocatalyst properties are rarely the focus of research efforts.A photomediated route to control the dispersion and oxidation state of a platinum(Pt)cocatalyst through defect generation in the P25 titania photocatalyst substrate is reported.Titania photoirradiation in the presence of methanol induces longlived Surface defects which subsequently promote the photodeposition of highly dispersed(2.2±0.8 nm)and heavily reduced Pt nanoparticles on exposure to H2 PtCl6.The optimal methanol concentration of 20 vol%produces the highest density of metallic Pt nanoparticles.Photocatalytic activity for water splitting and associated hydrogen(H2)production under UV irradiation mirrors the methanol concentration employed during the P25 photoirradiation pretreatment and resulting Pt loading resulting in a common mass-normalized H2 productivity of 3800±130 mmol gpt-1 h-1.Photomediated Surface defects(arising in the presence of a methanol hole scavenger)provide electron traps that regulate subsequent photodeposition of a Pt co-catalyst over P25,offering a facile route to tune photocatalytic efficiency.

关键词： methanol platinum Surface defects titanium

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Creation of Surface defects on carbon nanofibers by steam treatment

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Journal of Energy Chemistry 2013年第5期22卷 804-810页

作者： Zhengfeng Shao Min Pang Wei Xia Martin Muhler Changhai Liang Laboratory of Advanced Materials and Catalytic Engineering School of Chemical EngineeringDalian University of Technology Laboratory of Industrial Chemistry Ruhr University Bochum

A direct strategy for the creation of defects on carbon nanofibers (CNFs) has been developed by steam treatment.Nitrogen physisorption,XRD,Raman spectra,SEM and TEM analyses proved the existence of the new defects on CNFs.BET surface area of CNFs after steam treatment was enhanced from 20 to 378 m2/g.Pd catalysts supported on CNFs were also prepared by colloidal deposition method.The different activity of Pd/CNFs catalysts in the partial hydrogenation of phenylacetylene further demonstrated the diverse surfaces of CNFs could be formed by steam treatment.

关键词： carbon nanofibers Surface defects steam treatment palladium

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Surface defects of Cold-Rolled Ti-IF Steel Sheets due to Non-Metallic Inclusions

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Journal of Iron and Steel Research(International) 2011年第S2期18卷 335-340页

作者： CUI Heng1, WU Hua-jie1, YUE Feng1, WU Wei-shuang1, WANG Min1, BAO Yan-ping1, CHEN Bin2, JI Chen-xi2 (1. Engineering Research Institute, University of Science and Technology Beijing, Beijing 100083, China 2. Shougang Research Institute of Technology, Beijing 100043, China) Univ Sci & Technol Beijing Engn Res Inst Beijing 100083 Peoples R China Shougang Res Inst Technol Beijing 100043 Peoples R China

Surface defects of the cold-rolled sheets of Ti-IF steel were studied and analyzed. After analyzing Surface defects of cold-rolled sheets, such as shelling defects, holes and sliver defects by SEM/EDS, a variety of inclusions were found. In addition, the distribution of macro-inclusions in slabs was analyzed by MIDAS method. The results show the macroscopic inclusion bands of head slabs and normal slabs are in 1/8 slab thickness regions of both inner arc side and outer arc side. The formation process of the defects in the cold-rolled sheets was simulated with an experimental cold-rolling machine for comparison. The results show that there were three kinds of inclusions underneath the Surface defects: Al2O3, SiO2 and particles from slag entrainment, which were the main reason for defect formation during cold rolling.

关键词： Ti-IF steel cold-rolled sheet Surface defects inclusion

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Study on incident laser modulation using surface micro-defects on KH_2PO_4 crystal

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Chinese Physics B 2012年第6期21卷 249-256页

作者：陈明君程健李明全肖勇曲遵世王勇刚刘杰郑丽和苏良碧徐军 Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001China

KH2PO4 crystal is a crucial optical component of inertial confinement fusion. Modulation of an incident laser by surface micro-defects will induce the growth of surface damage, which largely restricts the enhancement of the laser induced damage threshold. The modulation of an incident laser by using different kinds of Surface defects are simulated by employing the three-dimensional finite-difference time-domain method. The results indicate that after the modulation of Surface defects, the light intensity distribution inside the crystal is badly distorted, with the light intensity enhanced symmetrically. The relations between modulation properties and defect geometries （e.g., width, morphology, and depth of defects） are quite different for different defects. The modulation action is most obvious when the width of Surface defects reaches 1.064 p-m. For defects with smooth morphology, such as spherical pits, the degree of modulation is the smallest and the light intensity distribution seems relatively uniform. The degree of modulation increases rapidly with the increase of the depth of Surface defects and becomes stable when the depth reaches a critical value. The critical depth is 1.064 μm for cuboid pits and radial cracks, while for ellipsoidal pits the value depends on both the width and the length of the defects.

关键词： KH2PO4 crystal Surface defects modulation degree three-dimensional finite-differencetime-domain

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Analytical Modeling and Mechanism Analysis of Time-Varying Excitation for Surface defects in Rolling Element Bearings

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Journal of Dynamics, Monitoring and Diagnostics 2023年第2期2卷 89-101页

作者： Laihao Yang Yu Sun Ruobin Sun Lixia Gao Xuefeng Chen State Key Laboratory for Manufacturing and Systems Engineering Xi’an Jiaotong UniversityXi’anChina AECC Sichuan Gas Turbine Establishment ChengduChina

Surface defects,including dents,spalls,and cracks,for rolling element bearings are the most common faults in rotating machinery.The accurate model for the time-varying excitation is the basis for the vibration mechanism analysis and fault feature extraction.However,in conventional investigations,this issue is not well and fully addressed from the perspective of theoretical analysis and physical derivation.In this study,an improved analytical model for time-varying displacement excitations(TVDEs)caused by Surface defects is theoretically formulated.First and foremost,the physical mechanism for the effect of defect sizes on the physical process of rolling element-defect interaction is revealed.According to the physical interaction mechanism between the rolling element and different types of defects,the relationship between time-varying displacement pulse and defect sizes is further analytically derived.With the obtained time-varying displacement pulse,the dynamic model for the deep groove bearings considering the internal excitation caused by the surface defect is established.The nonlinear vibration responses and fault features induced by Surface defects are analyzed using the proposed TVDE model.The results suggest that the presence of Surface defects may result in the occurrence of the dual-impulse phenomenon,which can serve as indexes for surface-defect fault diagnosis.

关键词： analytical model rolling bearings Surface defects time-varying excitation vibration mechanism

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Research of the light reflex Surface defects detection technology

Research of the light reflex surface defects detection techn...

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2007亚洲光电子会议光学设计与测试分会场

作者： Jiajun Tian Yong Yao* Yunxu Sun Weijie Shi Xinhui Zhao Xuelian YU Department of Electronic and Information Engineering Shenzhen Graduate School Harbin Institute of Technology Shenzhen China 518055

The Surface defects （indentations, humps, scores） of semiconductor wafers are the major factor to affect the performance of the semiconductor devices. Moreover, these defects make the manufacturing process difficult or yield of the semiconductor devices decrease. Consequently, it is necessary to do an on-line wafers detection in the benefit of the performance and yield of the devices. Thus, developing a way suited for practical detection is the urgent affair faced to people. The optical methods are the most suited ways for Surface defects detection because of their non-contact operation. We discuss a relatively unknown method of the light reflex Surface defects detection technology （Makyoh （or magic-mirror） topography （MT））. The optical system that we designed achieves the detection mode of the parallel light vertical incidence for the first time. It corrects the deviation between the tradition light path and arithmetic, promotes the detection precision. A lot of experiments based on this optical system are taken to get the difference between the detection modes of vertical incidence and the oblique incidence. The experiments prove that the vertical incidence mode excels the oblique incidence mode. The MT images are also analyzed and disposed. The quantitative measurement can be realized by digital image processing technology.

关键词： optical detection Surface defects Makyoh （magic-mirror） topography（MT） quantitative detection

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surface defect engineered-Mg-based implants enable the dual functions of superhydrophobic and synergetic photothermal/chemodynamic therapy

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Bioactive Materials 2023年第12期30卷 15-28页

作者： Dongdong Zhang Ru Xu Shuhan Chen Huihui Du Shi Qian Feng Peng Xuanyong Liu State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China Shenzhen Key Laboratory for Innovative Technology in Orthopaedic Trauma The University of Hong Kong Shenzhen HospitalShenzhenChina Center for Human Tissues and Organs Degeneration Shenzhen Institutes of Advanced TechnologyChinese Academy of ScienceShenzhen518055PR China Medical Research Institute Department of OrthopedicsGuangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern MedicalUniversityGuangzhou510080China GuangDong Engineering Technology Research Center of Functional Repair of Bone defects and Biomaterials Guangzhou510080China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences1 Sub-lane XiangshanHangzhou310024China

Promoting metallic magnesium(Mg)-based implants to treat bone diseases in clinics,such as osteosarcoma and bacterial infection,remains a challenging topic.Herein,an iron hydroxide-based composite coating with a twostage nanosheet-like structure was fabricated on Mg alloy,and this was followed by a thermal reduction treatment to break some of the surface Fe–OH bonds.The coating demonstrated three positive changes in properties due to the defects.First,the removal of–OH made the coating superhydrophobic,and it had self-cleaning and antifouling properties.This is beneficial for keeping the implants clean and for anti-corrosion before implantation into the human body.Furthermore,the superhydrophobicity could be removed by immersing the implant in a 75%ethanol solution,to further facilitate biological action during service.Second,the color of the coating changed from yellow to brown-black,leading to an increase in the light absorption,which resulted in an excellent photothermal effect.Third,the defects increased the Fe2+content in the coating and highly improved peroxidase activity.Thus,the defect coating exhibited synergistic photothermal/chemodynamic therapeutic effects for bacteria and tumors.Moreover,the coating substantially enhanced the anti-corrosion and biocompatibility of the Mg alloys.Therefore,this study offers a novel multi-functional Mg-based implant for osteosarcoma therapy.

关键词： Magnesium-based implants Surface defects Superhydrophobic Anti-bacterial Anti-tumor

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Neutral and metallic vs.charged and semiconducting surface layer in acceptor doped CeO_(2)

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 795-802页

作者： Ilan Riess Physics Department Technion IITHaifa 3200003Israel

The monomolecular surface layer of acceptor doped CeO_(2) may become neutral and metallic or charged and semiconducting.This is revealed in the theoretical analysis of the oxygen pressure dependence of the Surface defects concentration in acceptor doped ceria with two different dopant types and operated under different oxygen pressures.Recently published experimental data for highly reduced Sm0.2Ce0.8O1.9-x(SDC)containing a fixed valence dopant Sm3+are very different from those published for Pr0.1Ce0.9O_(2)-x(PCO) with the variable valence dopant Pr4+/Pr3+being reduced under milder conditions.The theoretical analysis of these experimental results fits very well the experimental results of SDC and PCO.It leads to the following predictions:the highly reduced surface of SDC is metallic and neutral,the metallic surface electron density of state is gs=0.9×10^(38)J-1·m^(-2)(1.4×1015eV^(-1)·cm^(-2)),the electron effective mass is meff,s=3.3me,and the phase diagram of the reduced surface has theα(fcc)structure as in the bulk.In PCO a double layer is predicted to be formed between the surface and the bulk with the surface being negatively charged and semiconducting.The surface of PCO maintains high Pr^(3+) defect concentration as well as relative high oxygen vacancy concentration at oxygen pressures higher than in the bulk.The reasons for the difference between a metallic and semiconducting surface layer of acceptor doped CeO_(2) are reviewed,as well as the key theoretical considerations applied in coping with this problem.For that we make use of the experimental data and theoretical analysis available for acceptor doped ceria.

关键词： CeO_(2) Surface defects metallic surface oxide reduction Sm doped CeO_(2) Pr doped CeO_(2)

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Highly efficient and stable organic solar cells with SnO_(2)electron transport layer enabled by UV-curing acrylate oligomers

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Journal of Energy Chemistry 2024年第5期92卷 124-131页

作者： Mwende Mbilo Du Hyeon Ryu Seungjin Lee Muhammad Haris Julius Mwakondo Mwabora Robinson Juma Musembi Hang Ken Lee Sang Kyu Lee Chang Eun Song Won Suk Shin Department of Physics Faculty of Science and TechnologyUniversity of Nairobi(UoN)P.O.Box 30197-00100NairobiKenya Advanced Energy Materials Research Center Korea Research Institute of Chemical Technology(KRICT)Daejeon 34114Republic of Korea Advanced Materials and Chemical Engineering University of Science and Technology(UST)Daejeon 34113Republic of Korea

The interfaces between the inorganic metal oxide and organic photoactive layer are of outmost importance for efficiency and stability in organic solar cells(OSCs).Tin oxide(SnO_(2))is one of the promising candidates for the electron transport layer(ETL)in high-performance inverted OSCs.When a solution-processed SnO_(2)ETL is employed,however,the presence of interfacial defects and suboptimal interfacial contact can lower the power conversion efficiency(PCE)and operational stability of OSCs.Herein,highly efficient and stable inverted OSCs by modification of the SnO_(2)surface with ultraviolet(UV)-curable acrylate oligomers(SAR and OCS)are demonstrated.The highest PCEs of 16.6%and 17.0%are achieved in PM6:Y6-BO OSCs with the SAR and OCS,respectively,outperforming a device with a bare SnO_(2)ETL(PCE 13.8%).The remarkable enhancement of PCEs is attributed to the optimized interfacial contact,leading to mitigated Surface defects.More strikingly,improved light-soaking and thermal stability strongly correlated with the interfacial defects are demonstrated for OSCs based on SnO_(2)/UV cross-linked resins compared to OSCs utilizing bare SnO_(2).We believe that UV cross-linking oligomers will play a key role as interfacial modifiers in the future fabrication of large-area and flexible OSCs with high efficiency and stability.

关键词： Organic solar cells SnO_(2) Surface defects Ultraviolet resins Stability Cross-linking oligomers Non-halogenated solvent

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