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A comparative study of the osteogenic performance between the hierarchical micro/submicro-textured 3D-printed Ti6Al4V surface and the SLA surface

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Bioactive Materials 2020年第1期5卷 9-16页

作者： Jinkai Zhanga Jiaqiang Liu Chengtao Wang Fengshan Chen Xudong Wang Kaili Lin Department of Orthodontics School&Hospital of StomatologyTongji UniversityShanghai Engineering Research Center of Tooth Restoration and RegenerationShanghai200072China Department of Oral&Cranio-Maxillofacial Surgery Shanghai Ninth People’s HospitalCollege of StomatologyShanghai Jiao Tong University School of MedicineNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of Stomatology&Shanghai Research Institute of StomatologyShanghai200011China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China

Three-dimensional(3D)printed titanium and its alloys have broad application prospect in the field of biomedical implant materials,although the biological performance of the original surface should be improved.Learning from the development experience of conventional titanium implants,to construct a hierarchical hybrid topological surface is the future direction of efforts.Since the original 3D-printed(3D hereafter)Ti6Al4V surface inherently has micron-scale features,in the present study,we introduced submicron-scale pits on the original surface by acid etching to obtain a hierarchical micro/submicro-textured surface.The characteristic and biological performance of the 3D-printed and acid-etched(3DA hereafter)surface were evaluated in vitro and in vivo,compared with the conventional sandblasted,large-grit,acid-etched(SLA hereafter)surface.Our results suggested the adhesion,proliferation and osteogenic differentiation of bone marrow derived mesenchymal stromal cells(BMSCs),as well as the in vivo osseointegration on 3DA surfaces were significantly improved.However,the overall osteogenic performance of the 3DA surface was not as good as the conventional SLA surface.

关键词： 3D printing Ti6Al4V Surface modification Osteogenesis SLA

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Local and global well-posedness of entropy-bounded solutions to the compressible Navier-Stokes equations in multi-dimensions

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Science China Mathematics 2023年第10期66卷 2219-2242页

作者： jinkai Li Zhouping Xin South China Research Center for Applied Mathematics and Interdisciplinary Studies School of Mathematical SciencesSouth China Normal UniversityGuangzhou 510631China The Institute of Mathematical Sciences The Chinese University of Hong KongHong KongChina

Due to the high degeneracy and singularity of the entropy equation,the physical entropy for viscous and heat-conductive polytropic gases behaves singularly in the presence of vacuum,and it is thus a challenge to study its dynamics.It is shown in this paper that the uniform boundedness of the entropy and the inhomogeneous Sobolev regularities of the velocity and temperature can be propagated for viscous and heat-conductive gases in R3,provided that the initial vacuum occurs only at far fields with suitably slow decay of the initial density.Precisely,it is proved that for any strong solution to the Cauchy problem of the heat-conductive compressible Navier-Stokes equations,the corresponding entropy remains uniformly bounded,and the L2 regularities of the velocity and temperature can be propagated,up to the existing time of the solution,as long as the initial density vanishes only at far fields with a rate not faster than O(1/|x|^(2)).The main tools are some singularly weighted energy estimates and an elaborate De Giorgi-type iteration technique.We apply the De Giorgi-type iterations to different equations in establishing the lower and upper bounds of the entropy.

关键词： heat-conductive compressible Navier-Stokes equation strong solution far-field vacuum uniform boundedness of entropy inhomogeneous Sobolev space

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Novel Hollow Re-entrant Structures Improving Hydrophobicity of Metal Surfaces

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Nanomanufacturing and Metrology 2023年第2期6卷 27-36页

作者： Zhaoqiang Zou jinkai Xu Wanfei Ren Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing Changchun University of Science and TechnologyChangchun 130022China School of Mechanical and Electrical Engineering Changchun University of Science and TechnologyChangchun 130022China

Re-entrant structures have drawn increasing attention because of their hydrophobicity.However,it is very difficult to manufacture re-entrant structures at the micron scale on metal surfaces.In this study,we designed and manufactured novel hollow re-entrant structures employing laser ablation and electrodeposition technology.This designed hollow re-entrant structure on metal surfaces has been fabricated successfully,which has high processing efficiency and good repeatability.The morphology and size of the hollow re-entrant structures were characterized.We found that the hydrophobic performance of hollow re-entrant structures was improved after being in the atmosphere for 3 days.After electrodeposition,the static contact angle was 133°.However,after being placed in the atmosphere for 3 days,the static contact angle was 140.4°,which is 5.2%higher than that after electrochemical deposition.We explained the cause of this phenomenon.The change of element content on the surface of hollow re-entrant structures was used to indicate the formation of metal oxide.After being in the atmosphere for 3 days,oxygen content increased by 0.4%.The metal surfaces with hollow re-entrant structures have a broader application prospect.

关键词： Hollow re-entrant structures Electrodeposition Hydrophobic surface

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Percolation of carbon nanomaterials for high-k polymer nanocomposites

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Chinese Chemical Letters 2017年第11期28卷 2036-2044页

作者： jinkai Yuan Centre de Recherche Paul Pascal CNRS Université de Bordeaux Pessac 33600 France

High-k polymer composite materials are next-generation dielectrics that show amazing applications in diverse electrical and electronic devices. Establishing near-percolated network of conducting filler in an insulating polymer matrix is a promising approach to develop flexible high-k dielectrics. However, challenges still exist today on fine controlling the network morphology to achieve extremely high k values and low losses simultaneously. The relationship between the network morphology and the dielectric properties of polymer composites is raising a number of fundamental questions. Herein, recent progress towards high-k polymer composites based on carbon nanomaterials is reviewed. Particular attention is paid on the influence of the network morphology on the dielectric properties. Some perspectives that warrant further investigation in the future are also addressed.

关键词： Percolation Carbon nanomaterials Polymer composites Dielectric constant Permittivity

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Synthesis and luminescent properties of Ba_(3)Y_(3.88)Gd_(0.12)O_(9):Eu^(3+) phosphors with enhanced red emission

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Journal of Rare Earths 2022年第4期40卷 534-540,I0001页

作者： Guiyuan Liu Bin Liu jinkai Li Zongming Liu School of Materials Science and Engineering University of JinanJinan 250022China

In this work,the Gd^(3+)/Eu^(3+) activated Ba_(3)Y_(4)O_(9)(BYO)phosphors were successfully synthesized via coprecipitation method at 1400℃.The precursor composition,crystal structure stability,microscopic morphology,photoluminescence(PL)/photoluminescence excitation(PLE)spectra and fluorescence attenuation analysis of the phosphors are discussed in detail.The chemical composition of the precursor was determined by Fourier transform infrared spectroscopy(FT-IR)and thermogravimetry(TG)analysis;According to field emission-scanning electron microscopy(FE-SEM)analysis,it is found that the particle size of phosphor is uniform and the agglomeration is few.According to PL/PLE spectra analysis,Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) phosphors has the strongest excitation band at 260 nm and the strongest emission band at 614 nm,and the fluorescence intensity of Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) is higher than that of Ba_(3)Y^(3.4)Eu^(0.6)O_(9).The quenching concentration of Eu^(3+)in Ba_(3)Y_(3.88–4x)Eu_(4x)Gd_(0.12)O_(9) phosphors is x=0.15 and the mechanism of quenching concentration of Eu^(3+)is electric dipole-quadrupole type interactions.The lifetime value of Ba_(3)Y_(3.88–4x)Eu_(4x)Gd_(0.12)O_(9)(x=0.15)phosphors is 0.686 ms and decreases with the increase of Eu^(3+)content.In addition,the CIE chromaticity diagram of Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) phosphors is(0.66,0.34).Finally,the lamp beads assembled with Ba_(3)Y_(3.28)Eu_(0.6)Gd_(0.12)O_(9) phosphors have an ideal luminous effect.Therefore,the Ba_(3)Y_(3.88–4x)Eu_(4x)Gd_(0.12)O_(9) phosphors designed in this work may hopefully meet the requirements of various lighting and optical display applications.

关键词： Coprecipitation method Ba_(3)Y_(3.88)Gd_(0.12)O_(9):Eu^(3+)phosphor Luminescent property Rare earths

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Nanocomposites of CsPbBr_(3) perovskite quantum dots embedded in Gd_(2)O_(3):Eu^(3+) hollow spheres for LEDs application

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Journal of Rare Earths 2022年第10期40卷 1509-1518页

作者： Gang Wang Shangjun Yu Bin Liu Zongming Liu jinkai Li School of Materials Science and Engineering University of JinanJjinan 250022China

Gd_(2)O_(3):Eu^(3+)@CsPbBr_(3) quantum dots(QDs)mesoporous hollow nanocomposites with good luminescent properties and high stability were built.Among which,the hollow Gd_(2)O_(3):Eu^(3+)spheres and CsPbBr_(3) QDs were prepared by urea homogeneous precipitation and hot-injection method,respectively.Finally,the Gd_(2)O_(3):Eu^(3+)@CsPbBr_(3) QDs shell-core compounds were constructed through mechanical stirring.The structure,morphology,stability and luminescent properties were studied by Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry/thermogravity(DSC/TG),X-ray diffraction(XRD),field-emission scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM),photoluminescence excitation/photoluminescence(PLE/PL)and life decay tools.Compared to the original CsPbBr_(3) QDs,Gd_(2)O_(3):Eu^(3+)@CsPbBr_(3) QDs display better photostability,thermal stability and current stability.The resulting Gd_(2)O_(3):Eu^(3+)@CsPbBr_(3) QDs composite exhibits good yellow emission.The Gd_(2)O_(3):Eu^(3+)@CsPbBr_(3) QDs mixed silicone resin was directly coated on the blue LED chip,then the w-LED device with the color coordinate of(0.31,0.32)was successfully assembled.The Gd_(2) O_(3):Eu^(3+)@CsPbBr_(3) QDs compounds with excellent luminescent properties and stability are expected to be widely used in lighting and display areas.

关键词： Rare earth oxides Hollow mesoporous Stability Perovskite quantum dot Light-emitting diode

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Plant phosphate nutrition:sensing the stress

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Stress Biology 2022年第1期2卷 496-509页

作者： Viswanathan Satheesh Ayesha Tahir jinkai Li Mingguang Lei Shanghai Center for Plant Stress Biology CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghai 201602China Department of Biosciences COMSATS University IslamabadPark RoadIslamabadPakistan University of Chinese Academy of Sciences Beijing 100049China

Phosphorus(P)is obtained by plants as phosphate(Pi)from the soil and low Pi levels affects plant growth and development.Adaptation to low Pi condition entails sensing internal and external Pi levels and translating those signals to molecular and morphophysiological changes in the plant.In this review,we present findings related to local and systemin Pi sensing with focus the molecular mechanisms behind root system architectural changes and the impact of hormones and epigenetic mechanisms affecting those changes.We also present some of the recent advances in the Pi sensing and signaling mechanisms focusing on inositol pyrophosphate InsP8 and its interaction with SPX domain proteins to regulate the activity of the central regulator of the Pi starvation response,PHR.

关键词： Phosphate signaling Root system architecture Inositol pyrophosphates InsP8 SPX domain Plant Human

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Synthesis and luminescence properties of Tb^(3+)/Eu^(3+) co-doped GdAlO_3 phosphors with enhanced red emission

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Journal of Rare Earths 2018年第9期36卷 924-930页

作者： Qi Chen jinkai Li Wenzhi Wang School of Materials Science and Engineering University of Jinan

he（Gd0.97-xEuxTb0.03）AIO3（x= 0.005-0.07） phosphors were synthesized by the co-precipitation method,using ammonium bicarbonate as a precipitant.The combined technologies of FT-IR,XRD,FESEM,PLE/PL and photo luminescence decay analysis were used to study the phase evolution,morphologies and luminescent properties.The phosphors with good dispersion exhibit strong vivid red emission located at 617 nm（5 D0-7 F2 transition of Eu3＋） under the optimal excitation wavelength of 275 nm（4 f8-4 f75 d1 transition of Tb3＋,8 S7/2→6IJ transition of Gd3＋）.The presence of Gd3＋ and Tb3＋ excitation bands on the PLE spectra monitoring the Eu3＋ emission directly gives an evidence of Tb3＋ → Eu3＋ and Gd3＋ → Eu3＋ energy transfer,The emission intensity varies with the Eu3＋ amount,and the quenching concentration is ～5 at% which is close to the calculated value.The quenching mechanism is determined to be the exchange reaction between Eu3＋.The temperature-dependent PL analysis indicates that the best（Gd0.92Eu0.05Tb0.03）AlO3 sample possesses good thermally stable properties.All the（Gd0.97-xEuxTb0.03）AIO3 phosphors in this work have similar CIE chromaticity coordinates and color temperatures,which are（0.65 ± 0.02,0.35 ± 0.02） and ～2558 K,respectively.Fluorescence decay analysis shows that the lifetime for～617 nm emission decreases with the content of Eu3＋ and temperature increasing.Owing to the Tb3＋→ Eu3＋ energy transfer,the luminescent properties of the（Gd0.92Eu0.05Tb0.03）AlO3 phosphors are superior to the single Eu3＋ doped sample（Gd0.95Eu0.05）AlO3.As a result,the prepared phosphors may be widely used in solid-state display and light emitting devices.

关键词：（Gd0.97-xEUxTb0.03）AlO3 phosphors Carbonate precipitation Luminescence property Rare earths

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Red color Sr_(2)NaMg_(2)V_(3)O_(12):Eu^(3+)phosphor with high thermal stability for w-LEDs

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Journal of Rare Earths 2023年第11期41卷 1689-1695,I0002页

作者： jinkai Li Bin Liu Guiyuan Liu Quande Che Yizhong Lu Zongming Liu School of Materials Science and Engineering University of JinanJinan250022China Infovision Optoelectronics(Kunshan)Co. Ltd.Kunshan215333China

Sr_(2)NaMg_(2)V_(3)O_(12):xEu phosphors with uniform particle size/morphology and good dispersion can be synthesized via solid state reaction.Under the optimum excitation wavelength of ~340 nm,the Sr_(2)NaMg_(2)V_(3)O_(12):xEu phosphor displays the broad emission band at ~500 nm(blue-green emission,^(3)T_(1,2)→^(1)A_(1) transition of[VO_(4)]^(3-))and sharp emission peak at~610 nm(red emission,^(5)D_(0)→^(7)F_(2) transition of Eu^(3+)),respectively.With the Eu^(3+)content increasing,the emission intensity of[VO_(4)]^(3-)decreases gradually while the emission intensity of Eu^(3+)increases,which is ascribed to the energy transfer from[VO_(4)]^(3-)to Eu^(3+)ions.The decay time of[VO_(4)]^(3-)(-500 nm)increases gradually with the Eu^(3+)content increasing.The energy transfer efficiency and mechanism of[VO_(4)]^(3-)→Eu^(3+)ions were analyzed,respectively.The emission color of Sr_(2)NaMg_(2)V_(3)O_(12):xEu phosphor was regulated from green to red via altering the Eu^(3+)ions concentration.It is delightful for us that the white color emission can be just achieved when the Eu^(3+)content is 5 at%(x=0.05),and the w-LED can be assembled.By studying the luminescence temperature dependence and activation energy of Sr_(2)NaMg_(2)V_3O_(12):xEu phosphor,it is shown that the phosphor has good thermal stability.The Sr_(2)NaMg_(2)V_3O_(12):xEu powder is expected to be a new type of phosphor widely used in light and display areas.

关键词： Phosphor W-LEDs Thermal stability Energy transfer Rare earths

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Comparison of the Pore Structure of Ultralow-Permeability Reservoirs Between the East and West Subsags of the Lishui Sag Using Constant-Rate Mercury Injection

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Journal of Ocean University of China 2021年第2期20卷 315-328页

作者： WANG jinkai ZHANG Jinliang SHEN Wenlong LIU Hengyi Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China College of Geological Science and Engineering Shandong University of Science and TechnologyQingdao 266590China CNOOC Ltd. Shanghai BranchShanghai 200335China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

In this study, the differences in reservoir parameters, such as pore radius, throat radius, and pore-throat ratio, between the east and west subsags of the Lishui Sag are analyzed by using data obtained from a constant-rate mercury injection experiment. Furthermore, the quality of the reservoirs in the two subsags is systematically evaluated. Results show that the throat radius of the Lishui west subsag is larger than that of the east subsag, and this parameter has a positive correlation with reservoir quality. However, the pore-throat ratio of the east subsag is larger than that of the west subsag, which has an inverse relationship with reservoir quality. The main reasons for this reservoir difference can be attributed to sedimentation and diagenesis. The sedimentary facies types of the Lishui east subsag are the fan delta, shore lake, shallow lake, and shore shallow lake;their sandstone composition maturity is low;the clay mineral content is high;and the rock has undergone strong diagenesis. Therefore, the physical conditions of the reservoir are poor. However, the sandstones in the Lishui west subsag have weak cementation and compaction, mainly with an intergranular pore structure type, which leads to good connectivity between pores. Therefore, the storage performance and seepage capacity of the Lishui west subsag are better than those of the east subsag;the west subsag is the main area of oil and gas accumulation, as confirmed in the process of exploration and development.

关键词： Lishui Sag constant-rate mercury injection sedimentary facies diagenesis rock pore structure

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