In this study,the workability of cement-based grouts containing n-TiO 2 nanoparticles and fly ash has been investigated experimentally.Several characteristic quantities(including,but not limited to,the marsh cone flow...In this study,the workability of cement-based grouts containing n-TiO 2 nanoparticles and fly ash has been investigated experimentally.Several characteristic quantities(including,but not limited to,the marsh cone flow time,the mini slump spreading diameter and the plate cohesion meter value)have been measured for different percentages of these additives.The use of fly ash as a mineral additive has been found to result in improvements in terms of workability behavior as expected.Moreover,if nano titanium oxide is also used,an improvement can be obtained regarding the bleeding values for the cement-based grout mixes.Using such experimental data,a multi-layer perceptron artificial neural network model has been developed(5 neurons in the hidden layer of the network model have been developed using a total of 42 experimental data).70%of the data employed in this model have been used for training,15%for validation and 15%for the test phase.The results demonstrate that the artificial neural network model can predict Marsh cone flow time,mini slump spreading diameter and plate cohesion meter values with an average error of 0.15%.展开更多
Effects of titanium oxide (TiO 2) nanoparticles on Bel-7402 human hepatoma cells and L-02 human hepatocytes at different times were observed.Using cell culture,cell growth curves of Bel-7402 cells and L-02 cells trea...Effects of titanium oxide (TiO 2) nanoparticles on Bel-7402 human hepatoma cells and L-02 human hepatocytes at different times were observed.Using cell culture,cell growth curves of Bel-7402 cells and L-02 cells treated with TiO 2 nanoparticles were examined by MTT assay,and the cellular ultrastructure was observed by an analytical transmission electron microscope (ATEM).It is found that OD value of Bel-7402 cell treated with TiO 2 nanoparticles for 48-144h is obviously lower than that of control group (p<0.01).However the growth curve of L-02 cells is almost not affected by TiO 2 nanoparticles.ATEM and energy dispersive X ray (EDX) analyses show that there are obvious vacuoles increased heterolysosome,and particles with high electron density which are confirmed to be TiO 2 nanoparticles in Bel-7402 cytoplasm.More interestingly,it is alse found that TiO 2 nanoparticle obviously inhibits the proliferation of hepatoma cells by altering lysosome activity and destroying cytoplasm structure.The inhibition on proliferation of hepatocytes by TiO 2 nanoparticles is much slighter.The results demonstrate that TiO 2 nanoparticle has different killing effects on cancer cell and normal cell.展开更多
We study the extended gate ion sensitive structure,and deposit the titanium oxide (TiO_2) thin film on p-type (100) silicon substrate.The device of the hydrogen ion sensing structure is TiO_2/Si-substrate,and a commer...We study the extended gate ion sensitive structure,and deposit the titanium oxide (TiO_2) thin film on p-type (100) silicon substrate.The device of the hydrogen ion sensing structure is TiO_2/Si-substrate,and a commercial device of the metal oxide semiconductor field effect transistor (MOSFET) is connected to the separative sensing device.The sensitivity and linearity are measured under different work pressures.When the mixed ratio of Ar/O_2 is 80 ml·min^(-1)/20 ml·min^(-1),the work pressure is 4 Pa,the sputtering power is 150 W,and the sputtering time is two hours,the better sensing properties of the sensitivity and linearity are 36.49 mV/pH and 0.99654,respectively.However,some instruments are analyzed the surface of TiO_2 membrane,such as X-ray diffraction (XRD) and Auger Electron Spectrometer (AES).The characteristics of TiO_2 thin film can be demonstrated.展开更多
A series of three-dimensional ordered macroporous(3 DOM)W-TiO_(2)catalysts have been prepared through a facile colloidal crystal template method.The prepared materials characterized in detail exhibited enhanced cataly...A series of three-dimensional ordered macroporous(3 DOM)W-TiO_(2)catalysts have been prepared through a facile colloidal crystal template method.The prepared materials characterized in detail exhibited enhanced catalytic activity in aerobic oxidative desulfurization process.The experimental results indicated that the as-prepared materials possessed excellent 3 DOM structure,which is beneficial for the catalytic activity.The sample 3 DOM W-TiO_(2)-20 exhibited the highest activity in ODS process,and the sulfur removal can reach 98%in 6 h.Furthermore,the oxidative product was also analyzed in the reaction process.展开更多
The corrosion and weaker interaction with metal catalysts of common carbon supports during electrocatalysis push the development of alternative supports materials. Titanium oxide-based materials have been widely explo...The corrosion and weaker interaction with metal catalysts of common carbon supports during electrocatalysis push the development of alternative supports materials. Titanium oxide-based materials have been widely explored as electrocatalysts supports in consideration of their chemical stability, strong interactions with metal catalyst and wider applications in electrocatalytic reactions as well as the improved electronic conductivity. This review summarizes recent research advances in engineering titanium oxide-based supports for the catalysts in electrocatalysis field to provide guidance for designing high performance non-carbon supported electrocatalysts. Typically, the titanium oxide-based supports are classified into shaped TiO_(2), doped TiO_(2), titanium suboxide and TiO_(2)-carbon composites according to the modification methods and corresponding preparation methods. Then the engineering strategies and electrocatalytic applications are discussed in detail. Finally, the challenges, future research directions and perspectives of titanium oxide-based supports for electrocatalysis are presented for practical applications.展开更多
The recent published experimental data of titanium oxide memristor devices which are tested under the same experi- mental conditions exhibit the strange instability and complexity of these devices. Such undesired char...The recent published experimental data of titanium oxide memristor devices which are tested under the same experi- mental conditions exhibit the strange instability and complexity of these devices. Such undesired characteristics preclude the understanding of the device conductive processes and the memristor-based practical applications. The possibility of the coexistence of dopant drift and tunnel barrier conduction in a memristor provides preliminary explanations for the undesired characteristics. However, current research lacks detailed discussion about the coexistence case. In this paper, dopant drift and tunnel barrier-based theories are first analyzed for studying the relations between parameters and physical variables which affect characteristics of mernristors, and then the influences of each parameter change on the conductive behaviors in the single and coexistence cases of the two mechanisms are simulated and discussed respectively. The simulation results provide further explanations of the complex device conduction. Theoretical methods of eliminating or reducing the coex- istence of the two mechanisms are proposed, in order to increase the stability of the device conduction. This work also provides the support for optimizing the fabrications of memristor devices with excellent performance.展开更多
The preparation, characterization and properties of titania overlayer on Fe(110) substrate is hereby reported. The TiO;overlayer was found to form in a layer-by-layer mode with a suboxide of titanium in the form of ...The preparation, characterization and properties of titania overlayer on Fe(110) substrate is hereby reported. The TiO;overlayer was found to form in a layer-by-layer mode with a suboxide of titanium in the form of TiO migrating into the Fe substrate and Fe migrating into the deposited layer of TiO;simultaneously during the deposition.展开更多
Low-pressure dielectric barrier discharge(DBD) TiCl4/O2and N2 plasmas have been used to deposit titanium oxide films at different power supply driving frequencies. A homemade large area low pressure DBD reactor was ...Low-pressure dielectric barrier discharge(DBD) TiCl4/O2and N2 plasmas have been used to deposit titanium oxide films at different power supply driving frequencies. A homemade large area low pressure DBD reactor was applied, characterized by the simplicity of the experimental set-up and a low consumption of feed gas and electric power, as well as being easy to operate. Atomic force microscopy, scanning electron microscopy, energy dispersive spectroscopy,and contact angle measurements have been used to characterize the deposited films. Experimental results show all deposited films are uniform and hydrophilic with a contact angle of about 15 o.Compared to titanium oxide films deposited in TiCl4/O2gas mixtures, those in TiCl4/O2/N2gas mixtures are much more stable. The contact angle of titanium oxide films in TiCl4/O2/N2gas mixtures with the addition of 50% N2 and 20% TiCl4 is still smaller than 20 o, while that of undoped titanium oxide films is larger than 64 owhen they are measured after one week. The low-pressure TiCl4/O2plasmas consist of pulsed glow-like discharges with peak widths of several microseconds, which leads to the uniform deposition of titanium oxide films. Increasing a film thickness over several hundreds of nm leads to the film’s fragmentation due to the over-high film stress. Optical emission spectra(OES) of TiCl4/O2DBD plasmas at various power supply driving frequencies are presented.展开更多
This is second paper summarizing the study on the hydrous titanium oxide absorbent for extracting uranium fromseawater. The investigation is performed by means of X- ray photoelectronic energy spectroscopy for chemica...This is second paper summarizing the study on the hydrous titanium oxide absorbent for extracting uranium fromseawater. The investigation is performed by means of X- ray photoelectronic energy spectroscopy for chemical analysis ( ESC A ) , determination of surface hydroxy radical, Fourier-transfer infrared spectrophotometry (FT-IR ) , electron paramagnetic resonance (EPR), inductively coupled Plasma torch (ICP), etc. The emphasis is laid upon the exploration of HTO surface and a discussion about the adsorption micromechanism.展开更多
-The i. r. spectra of Na4 [UO2 (CO3)3], Na [UO2 (OH)3] and the surface species of uranium on HTO underthe condition of flowing natural seawater and concentrated seawater (NaCl-NaHCO3-U) were recorded, with the bands o...-The i. r. spectra of Na4 [UO2 (CO3)3], Na [UO2 (OH)3] and the surface species of uranium on HTO underthe condition of flowing natural seawater and concentrated seawater (NaCl-NaHCO3-U) were recorded, with the bands of urany! of surface species obtained and the finding that iigands of surface species besides HTO are mainly water and OH, and there are some CO32- groups under the condition of natural seawater. Some relations between the complex properties and the j. r. spectroscopic characters for uranyl complexes were studied, and the transferred change quantity of surface complex was calculated.Structure models for surface species of adsorption are herein presented and the mechanism for uranium adsorption is deduced.展开更多
In recent years there has increased interest in the characterization of titanium oxide nanorods for application in analytical devices. The titanium oxide nanorods (NRTiO) were obtained by hydrothermal reaction with a ...In recent years there has increased interest in the characterization of titanium oxide nanorods for application in analytical devices. The titanium oxide nanorods (NRTiO) were obtained by hydrothermal reaction with a NaOH solution heated in the autoclave at 150°C for up to 50 h. Experimental data indicate that the prepared nanorods consist of anatase and rutile phases, with a possible interlayer structure. The NRTiO was investigated as pH sensor in the pH range 2 - 12, and the extended gate field effect transistor (EGFET) configuration presented a sensitivity of 49.6 mV/pH. Voltammetric data showed a sensitivity of 47.8 mV/pH. These results indicate that the material is a promising candidate for applications as an EGFET-pH sensor and as a disposable biosensor in the future.展开更多
The prime objective of the present communication is to examine the entropy-optimized second order velocity slip Darcy–Forchheimer hybrid nanofluid flow of viscous material between two rotating disks.Electrical conduc...The prime objective of the present communication is to examine the entropy-optimized second order velocity slip Darcy–Forchheimer hybrid nanofluid flow of viscous material between two rotating disks.Electrical conducting flow is considered and saturated through Darcy–Forchheimer relation.Both the disks are rotating with different angular frequencies and stretches with different rates.Here graphene oxide and titanium dioxide are considered for hybrid nanoparticles and water as a continuous phase liquid.Joule heating,heat generation/absorption and viscous dissipation effects are incorporated in the mathematical modeling of energy expression.Furthermore,binary chemical reaction with activation energy is considered.The total entropy rate is calculated in the presence of heat transfer irreversibility,fluid friction irreversibility,Joule heating irreversibility,porosity irreversibility and chemical reaction irreversibility through thermodynamics second law.The nonlinear governing equations are first converted into ordinary differential equations through implementation of appropriate similarity transformations and then numerical solutions are calculated through Built-in-Shooting method.Characteristics of sundry flow variables on the entropy generation rate,velocity,concentration,Bejan number,temperature are discussed graphically for both graphene oxide and titanium dioxide hybrid nanoparticles.The engineering interest like skin friction coefficient and Nusselt number are computed numerically and presented through tables.It is noticed from the obtained results that entropy generation rate and Bejan number have similar effects versus diffusion parameter.Also entropy generation rate is more against the higher Brinkman number.展开更多
The paper shows the results of the mathematical model development and the numerical simulation of the oxygen vacancies,and the distribution of TiO,Ti_(2)O_(3),and TiO_(2)oxides in the titanium oxide nanostructure obta...The paper shows the results of the mathematical model development and the numerical simulation of the oxygen vacancies,and the distribution of TiO,Ti_(2)O_(3),and TiO_(2)oxides in the titanium oxide nanostructure obtained by local anodic oxidation(anodization).The effect of the anodization voltage pulse duration and amplitude on the titanium oxide composition distribution and the conduction channel formation was shown.Synaptic device prototypes based on electrochemical titanium oxide are fabricated and investigated.It was shown that forming free resistive switching between the low resistances state(LRS)1.43±0.54 kΩand the high resistance state(HRS)28.75±9.75 kΩwere observed during 100,000 switching cycles and LRS 1.49±0.23 kΩwas maintained for 10,000 s.Multilevel resistive switching of the synaptic device prototype was investigated.It was shown that increasing Uset from 0.5 to 1.5 V leads to different LRS from 3.96±0.19 to 0.71±0.10 kΩ.The results obtained can be used in the development of technological foundations for the formation of high-performance multilevel artificial synapses for elements of neuroelectronics and hardware neural networks.展开更多
The photothermal therapy (PTT) technique is regarded as a promising method for cancer treatment. However, one of the obstacles preventing its clinical application is the non-degradability and biotoxicity of the exis...The photothermal therapy (PTT) technique is regarded as a promising method for cancer treatment. However, one of the obstacles preventing its clinical application is the non-degradability and biotoxicity of the existing heavy-metal and carbon-based therapeutic agents. Therefore, a PTT material with a high photothermal efficiency, low toxicity, and good biocompatibility is urgently wanted. Herein, we report a titanium oxide-based therapeutic agent with a high efficacy and low toxicity for the PTT process. We demonstrated that Magneliphase Ti8015 nanoparticles fabricated by the arc-melting method exhibit 〉98% absorption of near infrared light and a superior photothermal therapy effect in the in vivo mouse model. The Ti8O15 nanoparticle PTT material also shows a good biocompatibility and biosafety. Our study reveals Magneli-phase titanium oxide as a new family of PTT agents and introduces new applications of titanium oxides for photothermal conversion.展开更多
We have successfully prepared a series of Pd- Ni/TiO2 catalysts by a one-step impregnation-reduction method. Among these catalysts with different compositions of Ni and Pd, the one with the Ni:Pd ratio of 2.95 showed...We have successfully prepared a series of Pd- Ni/TiO2 catalysts by a one-step impregnation-reduction method. Among these catalysts with different compositions of Ni and Pd, the one with the Ni:Pd ratio of 2.95 showed the best activity. Small monodispersed Pd-Ni bimetallic nanoparticles were loaded on the surface of titanium oxide nanopowder as confirmed with TEM and EDS mapping. The XPS analysis demonstrated that Pd exists as 31% Pd(II) species and 69% Pd(0) species and all nickel is Ni(II). The prepared Pd-Ni/TiO2 exhibited enhanced catalytic activity compared to an equal amount of Pd/TiO2 for Suzuki-Miyaura reactions together with excellent applicability and reusability.展开更多
Precise catalysis is critical for the high-quality catalysis industry.However,it remains challenging to fundamentally understand precise catalysis at the atomic orbital level.Herein,we propose a new strategy to unrave...Precise catalysis is critical for the high-quality catalysis industry.However,it remains challenging to fundamentally understand precise catalysis at the atomic orbital level.Herein,we propose a new strategy to unravel the role of specific d orbitals in catalysis.The oxygen reduction reaction(ORR)catalyzed by atomically dispersed Pt/Co-doped Ti_(1−x)O_(2) nanosheets(Pt_(1)/Co_(1)-Ti_(1−x)O_(2))is used as a model catalysis.The z-axis d orbitals of Pt/Co-Ti realms dominate the O2 adsorption,thus triggering ORR.In light of orbital-resolved analysis,Pt_(1)/Co_(1)-Ti_(1−x)O_(2) is experimentally fabricated,and the excellent ORR catalytic performance is further demonstrated.Further analysis reveals that the superior ORR performance of Pt_(1)-Ti_(1−x)O_(2) to Co_(1)-Ti_(1−x)O_(2) is ascribed to stronger activation of Ti by Pt than Co via the d-d hybridization.Overall,this work provides a useful tool to understand the underlying catalytic mechanisms at the atomic orbital level and opens new opportunities for precise catalyst design.展开更多
Resistive switching devices with a high self-rectifying ratio are important for achieving the crossbar memristor array that overcomes the sneak current issue.Herein,we demonstrate a single amorphous lithium lanthanum ...Resistive switching devices with a high self-rectifying ratio are important for achieving the crossbar memristor array that overcomes the sneak current issue.Herein,we demonstrate a single amorphous lithium lanthanum titanium oxide(LLTO)layer based Pt/LLTO/Pt device possessing a self-rectifying ratio higher than 1 × 10^(4) that is comparable to the reported devices with complicated multi-layer stacking structures.Moreover,the device shows forming-free and highly uniform bipolar resistive switching(BRS)characteristic that facilitates the potential applications.The trap-controlled and trap-free space charge limited conductions are demonstrated to dominate the high and low resistance states of the device,respectively.The fast migration of lithium ions under external voltage accelerates the electron injection across the Pt/LLTO interface and also the space charge accumulation in the LLTO layer,and as a result,the high performance of the Pt/LLTO/Pt device was achieved.As demonstrated Pt/LLTO/Pt device sheds a light on the potential applications of the lithium ionic conductors in self-rectifying resistive switching devices.展开更多
Titanium oxide films were prepared by annealing DC magnetron sputtered titanium films in an oxygen ambient. X-ray diffraction (XRD), Auger electron spectroscopy (AES) sputter profiling, MCs^+-mode secondary ion m...Titanium oxide films were prepared by annealing DC magnetron sputtered titanium films in an oxygen ambient. X-ray diffraction (XRD), Auger electron spectroscopy (AES) sputter profiling, MCs^+-mode secondary ion mass spectrometry (MCs^+-SIMS) and atomic force microscopy (AFM) were employed, respectively, for the structural, com- positional and morphological characterization of the obtained films. For temperatures below 875 K, titanium films could not be fully oxidized within one hour. Above that temperature, the completely oxidized films were found to be rutile in structure. Detailed studies on the oxidation process at 925K were carried out for the understanding of the underlying mechanism of titanium dioxide (TiO2) formation by thermal oxidation. It was demonstrated that the formation of crystalline TiO2 could be divided into a short oxidation stage, followed by crystal forming stage. Relevance of this recognition was further discussed.展开更多
CO2 and O2 were employed as reactive gases to fabricate carbon-doped titanium oxide films using DC reactive magnetron sputtering. Microstructure, composition and optical band gap of the films were investigated by X-ra...CO2 and O2 were employed as reactive gases to fabricate carbon-doped titanium oxide films using DC reactive magnetron sputtering. Microstructure, composition and optical band gap of the films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and UV-visible spectrophotometer, respectively. The results showed that carbon-doped titanium monoxide films (C-TiO) with a carbon concentration of 5.8 at.% were obtained in an AffCO2 mixed atmosphere. However, carbon-doped futile and anatase (C-TiO2) with a carbon concentration of about 1.4 at.% were obtained in an Ar/CO2/O2 mixed atmosphere. The optical band gaps of C-TiO and C-TiO2 were about 2.6 and 2.9 eV, respectively. Both of them were narrower than that of pure TiO2 films. Films with narrowed optical band gap energy are promising in promoting their photo-catalytic activity.展开更多
基金funded by The Scientific and Technological Research Council of Turkey-TUBITAK[Grant No.219M522].
文摘In this study,the workability of cement-based grouts containing n-TiO 2 nanoparticles and fly ash has been investigated experimentally.Several characteristic quantities(including,but not limited to,the marsh cone flow time,the mini slump spreading diameter and the plate cohesion meter value)have been measured for different percentages of these additives.The use of fly ash as a mineral additive has been found to result in improvements in terms of workability behavior as expected.Moreover,if nano titanium oxide is also used,an improvement can be obtained regarding the bleeding values for the cement-based grout mixes.Using such experimental data,a multi-layer perceptron artificial neural network model has been developed(5 neurons in the hidden layer of the network model have been developed using a total of 42 experimental data).70%of the data employed in this model have been used for training,15%for validation and 15%for the test phase.The results demonstrate that the artificial neural network model can predict Marsh cone flow time,mini slump spreading diameter and plate cohesion meter values with an average error of 0.15%.
基金FundedbytheNationalNaturalScienceFoundationofChina (No :39770 2 2 5 )
文摘Effects of titanium oxide (TiO 2) nanoparticles on Bel-7402 human hepatoma cells and L-02 human hepatocytes at different times were observed.Using cell culture,cell growth curves of Bel-7402 cells and L-02 cells treated with TiO 2 nanoparticles were examined by MTT assay,and the cellular ultrastructure was observed by an analytical transmission electron microscope (ATEM).It is found that OD value of Bel-7402 cell treated with TiO 2 nanoparticles for 48-144h is obviously lower than that of control group (p<0.01).However the growth curve of L-02 cells is almost not affected by TiO 2 nanoparticles.ATEM and energy dispersive X ray (EDX) analyses show that there are obvious vacuoles increased heterolysosome,and particles with high electron density which are confirmed to be TiO 2 nanoparticles in Bel-7402 cytoplasm.More interestingly,it is alse found that TiO 2 nanoparticle obviously inhibits the proliferation of hepatoma cells by altering lysosome activity and destroying cytoplasm structure.The inhibition on proliferation of hepatocytes by TiO 2 nanoparticles is much slighter.The results demonstrate that TiO 2 nanoparticle has different killing effects on cancer cell and normal cell.
文摘We study the extended gate ion sensitive structure,and deposit the titanium oxide (TiO_2) thin film on p-type (100) silicon substrate.The device of the hydrogen ion sensing structure is TiO_2/Si-substrate,and a commercial device of the metal oxide semiconductor field effect transistor (MOSFET) is connected to the separative sensing device.The sensitivity and linearity are measured under different work pressures.When the mixed ratio of Ar/O_2 is 80 ml·min^(-1)/20 ml·min^(-1),the work pressure is 4 Pa,the sputtering power is 150 W,and the sputtering time is two hours,the better sensing properties of the sensitivity and linearity are 36.49 mV/pH and 0.99654,respectively.However,some instruments are analyzed the surface of TiO_2 membrane,such as X-ray diffraction (XRD) and Auger Electron Spectrometer (AES).The characteristics of TiO_2 thin film can be demonstrated.
基金the financial support from the National Natural Science Foundation of China(Nos.21722604 and 21776116)China Postdoctoral Science Foundation(2020M671365)+2 种基金Jiangsu Postdoctoral Research Funding Program(No.2021K343C)Natural Science Foundation of Jiangsu Province(No.BK20190243)the Society Development Fund of Zhenjiang City(SH2020020)。
文摘A series of three-dimensional ordered macroporous(3 DOM)W-TiO_(2)catalysts have been prepared through a facile colloidal crystal template method.The prepared materials characterized in detail exhibited enhanced catalytic activity in aerobic oxidative desulfurization process.The experimental results indicated that the as-prepared materials possessed excellent 3 DOM structure,which is beneficial for the catalytic activity.The sample 3 DOM W-TiO_(2)-20 exhibited the highest activity in ODS process,and the sulfur removal can reach 98%in 6 h.Furthermore,the oxidative product was also analyzed in the reaction process.
基金supported by the National Natural Science Foundation of China(91963109)the Innovation Research Funds of the Huazhong University of Science and Technology(2019kfyR CPY100)。
文摘The corrosion and weaker interaction with metal catalysts of common carbon supports during electrocatalysis push the development of alternative supports materials. Titanium oxide-based materials have been widely explored as electrocatalysts supports in consideration of their chemical stability, strong interactions with metal catalyst and wider applications in electrocatalytic reactions as well as the improved electronic conductivity. This review summarizes recent research advances in engineering titanium oxide-based supports for the catalysts in electrocatalysis field to provide guidance for designing high performance non-carbon supported electrocatalysts. Typically, the titanium oxide-based supports are classified into shaped TiO_(2), doped TiO_(2), titanium suboxide and TiO_(2)-carbon composites according to the modification methods and corresponding preparation methods. Then the engineering strategies and electrocatalytic applications are discussed in detail. Finally, the challenges, future research directions and perspectives of titanium oxide-based supports for electrocatalysis are presented for practical applications.
基金supported by the National Natural Science Foundation of China(Grant No.61171017)
文摘The recent published experimental data of titanium oxide memristor devices which are tested under the same experi- mental conditions exhibit the strange instability and complexity of these devices. Such undesired characteristics preclude the understanding of the device conductive processes and the memristor-based practical applications. The possibility of the coexistence of dopant drift and tunnel barrier conduction in a memristor provides preliminary explanations for the undesired characteristics. However, current research lacks detailed discussion about the coexistence case. In this paper, dopant drift and tunnel barrier-based theories are first analyzed for studying the relations between parameters and physical variables which affect characteristics of mernristors, and then the influences of each parameter change on the conductive behaviors in the single and coexistence cases of the two mechanisms are simulated and discussed respectively. The simulation results provide further explanations of the complex device conduction. Theoretical methods of eliminating or reducing the coex- istence of the two mechanisms are proposed, in order to increase the stability of the device conduction. This work also provides the support for optimizing the fabrications of memristor devices with excellent performance.
文摘The preparation, characterization and properties of titania overlayer on Fe(110) substrate is hereby reported. The TiO;overlayer was found to form in a layer-by-layer mode with a suboxide of titanium in the form of TiO migrating into the Fe substrate and Fe migrating into the deposited layer of TiO;simultaneously during the deposition.
基金supported by National Natural Science Foundation of China(Nos.10875025 and 20803007)Fundamental Research Funds for Central Universities of China(Nos.DC12010116 and DC13010106)Program for Liaoning Excellent Talents in University(LJQ20l3128)
文摘Low-pressure dielectric barrier discharge(DBD) TiCl4/O2and N2 plasmas have been used to deposit titanium oxide films at different power supply driving frequencies. A homemade large area low pressure DBD reactor was applied, characterized by the simplicity of the experimental set-up and a low consumption of feed gas and electric power, as well as being easy to operate. Atomic force microscopy, scanning electron microscopy, energy dispersive spectroscopy,and contact angle measurements have been used to characterize the deposited films. Experimental results show all deposited films are uniform and hydrophilic with a contact angle of about 15 o.Compared to titanium oxide films deposited in TiCl4/O2gas mixtures, those in TiCl4/O2/N2gas mixtures are much more stable. The contact angle of titanium oxide films in TiCl4/O2/N2gas mixtures with the addition of 50% N2 and 20% TiCl4 is still smaller than 20 o, while that of undoped titanium oxide films is larger than 64 owhen they are measured after one week. The low-pressure TiCl4/O2plasmas consist of pulsed glow-like discharges with peak widths of several microseconds, which leads to the uniform deposition of titanium oxide films. Increasing a film thickness over several hundreds of nm leads to the film’s fragmentation due to the over-high film stress. Optical emission spectra(OES) of TiCl4/O2DBD plasmas at various power supply driving frequencies are presented.
文摘This is second paper summarizing the study on the hydrous titanium oxide absorbent for extracting uranium fromseawater. The investigation is performed by means of X- ray photoelectronic energy spectroscopy for chemical analysis ( ESC A ) , determination of surface hydroxy radical, Fourier-transfer infrared spectrophotometry (FT-IR ) , electron paramagnetic resonance (EPR), inductively coupled Plasma torch (ICP), etc. The emphasis is laid upon the exploration of HTO surface and a discussion about the adsorption micromechanism.
文摘-The i. r. spectra of Na4 [UO2 (CO3)3], Na [UO2 (OH)3] and the surface species of uranium on HTO underthe condition of flowing natural seawater and concentrated seawater (NaCl-NaHCO3-U) were recorded, with the bands of urany! of surface species obtained and the finding that iigands of surface species besides HTO are mainly water and OH, and there are some CO32- groups under the condition of natural seawater. Some relations between the complex properties and the j. r. spectroscopic characters for uranyl complexes were studied, and the transferred change quantity of surface complex was calculated.Structure models for surface species of adsorption are herein presented and the mechanism for uranium adsorption is deduced.
基金This work was supported by FAPESP,FAPEMIG,CNPq and CAPES
文摘In recent years there has increased interest in the characterization of titanium oxide nanorods for application in analytical devices. The titanium oxide nanorods (NRTiO) were obtained by hydrothermal reaction with a NaOH solution heated in the autoclave at 150°C for up to 50 h. Experimental data indicate that the prepared nanorods consist of anatase and rutile phases, with a possible interlayer structure. The NRTiO was investigated as pH sensor in the pH range 2 - 12, and the extended gate field effect transistor (EGFET) configuration presented a sensitivity of 49.6 mV/pH. Voltammetric data showed a sensitivity of 47.8 mV/pH. These results indicate that the material is a promising candidate for applications as an EGFET-pH sensor and as a disposable biosensor in the future.
基金supported by the National Natural Science Foundation of China(Grant Nos.11971142,11871202,61673169,11701176,11626101,and 11601485)。
文摘The prime objective of the present communication is to examine the entropy-optimized second order velocity slip Darcy–Forchheimer hybrid nanofluid flow of viscous material between two rotating disks.Electrical conducting flow is considered and saturated through Darcy–Forchheimer relation.Both the disks are rotating with different angular frequencies and stretches with different rates.Here graphene oxide and titanium dioxide are considered for hybrid nanoparticles and water as a continuous phase liquid.Joule heating,heat generation/absorption and viscous dissipation effects are incorporated in the mathematical modeling of energy expression.Furthermore,binary chemical reaction with activation energy is considered.The total entropy rate is calculated in the presence of heat transfer irreversibility,fluid friction irreversibility,Joule heating irreversibility,porosity irreversibility and chemical reaction irreversibility through thermodynamics second law.The nonlinear governing equations are first converted into ordinary differential equations through implementation of appropriate similarity transformations and then numerical solutions are calculated through Built-in-Shooting method.Characteristics of sundry flow variables on the entropy generation rate,velocity,concentration,Bejan number,temperature are discussed graphically for both graphene oxide and titanium dioxide hybrid nanoparticles.The engineering interest like skin friction coefficient and Nusselt number are computed numerically and presented through tables.It is noticed from the obtained results that entropy generation rate and Bejan number have similar effects versus diffusion parameter.Also entropy generation rate is more against the higher Brinkman number.
基金The reported study was funded by the Russian Federation Government(Agreement No.075-15-2022-1123)(mathematical model development and theoretical calculations)The fabrication of memristor structures and their resistive switching investigation were supported by a grant from the Russian Science Foundation No.22-79-10215,https://rscf.ru/project/22-79-10215/,at Southern Federal University.Multilevel switching was researched with the financial support of the grant of the President of the Russian FederationМК-2290.2022.4。
文摘The paper shows the results of the mathematical model development and the numerical simulation of the oxygen vacancies,and the distribution of TiO,Ti_(2)O_(3),and TiO_(2)oxides in the titanium oxide nanostructure obtained by local anodic oxidation(anodization).The effect of the anodization voltage pulse duration and amplitude on the titanium oxide composition distribution and the conduction channel formation was shown.Synaptic device prototypes based on electrochemical titanium oxide are fabricated and investigated.It was shown that forming free resistive switching between the low resistances state(LRS)1.43±0.54 kΩand the high resistance state(HRS)28.75±9.75 kΩwere observed during 100,000 switching cycles and LRS 1.49±0.23 kΩwas maintained for 10,000 s.Multilevel resistive switching of the synaptic device prototype was investigated.It was shown that increasing Uset from 0.5 to 1.5 V leads to different LRS from 3.96±0.19 to 0.71±0.10 kΩ.The results obtained can be used in the development of technological foundations for the formation of high-performance multilevel artificial synapses for elements of neuroelectronics and hardware neural networks.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China (Nos. 51302180, 51222203, 51002100, and 51132006), the National Basic Research Program of China (Nos. 2011CB911002 and 2012CB932601), and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘The photothermal therapy (PTT) technique is regarded as a promising method for cancer treatment. However, one of the obstacles preventing its clinical application is the non-degradability and biotoxicity of the existing heavy-metal and carbon-based therapeutic agents. Therefore, a PTT material with a high photothermal efficiency, low toxicity, and good biocompatibility is urgently wanted. Herein, we report a titanium oxide-based therapeutic agent with a high efficacy and low toxicity for the PTT process. We demonstrated that Magneliphase Ti8015 nanoparticles fabricated by the arc-melting method exhibit 〉98% absorption of near infrared light and a superior photothermal therapy effect in the in vivo mouse model. The Ti8O15 nanoparticle PTT material also shows a good biocompatibility and biosafety. Our study reveals Magneli-phase titanium oxide as a new family of PTT agents and introduces new applications of titanium oxides for photothermal conversion.
基金Acknowledgements We are grateful for financial support from the National Key R&D Program of China (Grant No. 2016YFA0202900), the National Natural Science Foundation of China (Grant Nos. 21376212 and 21436010).
文摘We have successfully prepared a series of Pd- Ni/TiO2 catalysts by a one-step impregnation-reduction method. Among these catalysts with different compositions of Ni and Pd, the one with the Ni:Pd ratio of 2.95 showed the best activity. Small monodispersed Pd-Ni bimetallic nanoparticles were loaded on the surface of titanium oxide nanopowder as confirmed with TEM and EDS mapping. The XPS analysis demonstrated that Pd exists as 31% Pd(II) species and 69% Pd(0) species and all nickel is Ni(II). The prepared Pd-Ni/TiO2 exhibited enhanced catalytic activity compared to an equal amount of Pd/TiO2 for Suzuki-Miyaura reactions together with excellent applicability and reusability.
基金supported by the Fundamental Research Funds for the Central Universities(grant nos.2018JBZ107 and 2019RC035)supported financially by the National Natural Science Foundation of China(grant nos.91961125 and 21905019)+1 种基金the Key Program for International S&T Cooperation Projects of China from the Ministry of Science and Technology of China(grant no.2018YFE0124600)the Chemistry and Chemical Engineering Guangdong Laboratory(nos.1932001,1932004,1911020,and 1911023).
文摘Precise catalysis is critical for the high-quality catalysis industry.However,it remains challenging to fundamentally understand precise catalysis at the atomic orbital level.Herein,we propose a new strategy to unravel the role of specific d orbitals in catalysis.The oxygen reduction reaction(ORR)catalyzed by atomically dispersed Pt/Co-doped Ti_(1−x)O_(2) nanosheets(Pt_(1)/Co_(1)-Ti_(1−x)O_(2))is used as a model catalysis.The z-axis d orbitals of Pt/Co-Ti realms dominate the O2 adsorption,thus triggering ORR.In light of orbital-resolved analysis,Pt_(1)/Co_(1)-Ti_(1−x)O_(2) is experimentally fabricated,and the excellent ORR catalytic performance is further demonstrated.Further analysis reveals that the superior ORR performance of Pt_(1)-Ti_(1−x)O_(2) to Co_(1)-Ti_(1−x)O_(2) is ascribed to stronger activation of Ti by Pt than Co via the d-d hybridization.Overall,this work provides a useful tool to understand the underlying catalytic mechanisms at the atomic orbital level and opens new opportunities for precise catalyst design.
基金supported by the National Key Research and Development Program of China(No.2019YFB2005801)the National Natural Science Foundation of China(Nos.52061135205,51731003,51971024,51971023,51971027,51927802)the Beijing Natural Science Foundation Key Program(No.Z190007)。
文摘Resistive switching devices with a high self-rectifying ratio are important for achieving the crossbar memristor array that overcomes the sneak current issue.Herein,we demonstrate a single amorphous lithium lanthanum titanium oxide(LLTO)layer based Pt/LLTO/Pt device possessing a self-rectifying ratio higher than 1 × 10^(4) that is comparable to the reported devices with complicated multi-layer stacking structures.Moreover,the device shows forming-free and highly uniform bipolar resistive switching(BRS)characteristic that facilitates the potential applications.The trap-controlled and trap-free space charge limited conductions are demonstrated to dominate the high and low resistance states of the device,respectively.The fast migration of lithium ions under external voltage accelerates the electron injection across the Pt/LLTO interface and also the space charge accumulation in the LLTO layer,and as a result,the high performance of the Pt/LLTO/Pt device was achieved.As demonstrated Pt/LLTO/Pt device sheds a light on the potential applications of the lithium ionic conductors in self-rectifying resistive switching devices.
文摘Titanium oxide films were prepared by annealing DC magnetron sputtered titanium films in an oxygen ambient. X-ray diffraction (XRD), Auger electron spectroscopy (AES) sputter profiling, MCs^+-mode secondary ion mass spectrometry (MCs^+-SIMS) and atomic force microscopy (AFM) were employed, respectively, for the structural, com- positional and morphological characterization of the obtained films. For temperatures below 875 K, titanium films could not be fully oxidized within one hour. Above that temperature, the completely oxidized films were found to be rutile in structure. Detailed studies on the oxidation process at 925K were carried out for the understanding of the underlying mechanism of titanium dioxide (TiO2) formation by thermal oxidation. It was demonstrated that the formation of crystalline TiO2 could be divided into a short oxidation stage, followed by crystal forming stage. Relevance of this recognition was further discussed.
基金supported by the National Natural Science Foundation of China (Nos.81171462 and 51062002)the Sichuan Youth Science & Technology Foundation for Distinguished Young Scholars (No.2012JQ0001)the Fundamental Research Funds for the Central Universities (Nos.SWJTU11CX078 and SWJTU12ZT08)
文摘CO2 and O2 were employed as reactive gases to fabricate carbon-doped titanium oxide films using DC reactive magnetron sputtering. Microstructure, composition and optical band gap of the films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and UV-visible spectrophotometer, respectively. The results showed that carbon-doped titanium monoxide films (C-TiO) with a carbon concentration of 5.8 at.% were obtained in an AffCO2 mixed atmosphere. However, carbon-doped futile and anatase (C-TiO2) with a carbon concentration of about 1.4 at.% were obtained in an Ar/CO2/O2 mixed atmosphere. The optical band gaps of C-TiO and C-TiO2 were about 2.6 and 2.9 eV, respectively. Both of them were narrower than that of pure TiO2 films. Films with narrowed optical band gap energy are promising in promoting their photo-catalytic activity.