The Experts below are selected from a list of 49110 Experts worldwide ranked by ideXlab platform
Xiaoxing Zhang - One of the best experts on this subject based on the ideXlab platform.
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pristine and cu decorated hexagonal inn monolayer a promising candidate to detect and scavenge sf6 decompositions based on first principle study
Journal of Hazardous Materials, 2019Co-Authors: Dachang Chen, Xiaoxing Zhang, Ju Tang, Zhaolun Cui, Hao CuiAbstract:Abstract We carried out the first-principle study of four types of SF6 decompositions adsorbed on pristine and Cu atom decorated hexagonal InN monolayer. The adsorption structures, adsorption energy, electron transfer, band structure, density of states and desorption properties were discussed to evaluate the possible application of InN monolayer in field of adsorbent and Gas sensor. The results revealed that the pristine InN monolayer has the largest adsorption energy to SO2 with evident chemical interactions. The introduction of Cu adatom on InN monolayer significantly enhanced the chemical interactions between the InN monolayer and the SO2, SOF2, SO2F2 Gas Molecule but declined the adsorption energy of HF. We also investigated the electronic properties of all adsorption configurations and estimated the desorption time of every Gas Molecule from pristine and Cu decorated InN monolayer to evaluate the potential application in noxious Gas detecting and scavenging in Gas insulated switch-gear (GIS).
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Ni-CNT Chemical Sensor for SF6 Decomposition Components Detection: A Combined Experimental and Theoretical Study
Sensors, 2018Co-Authors: Xiaoxing Zhang, Peigeng Lv, Chao Tang, Shan Wang, Qu ZhouAbstract:SF6 decomposition components detection is a key technology to evaluate and diagnose the insulation status of SF6-insulated equipment online, especially when insulation defects-induced discharge occurs in equipment. In order to detect the type and concentration of SF6 decomposition components, a Ni-modified carbon nanotube (Ni-CNT) Gas sensor has been prepared to analyze its Gas sensitivity and selectivity to SF6 decomposition components based on an experimental and density functional theory (DFT) theoretical study. Experimental results show that a Ni-CNT Gas sensor presents an outstanding Gas sensing property according to the significant change of conductivity during the Gas Molecule adsorption. The conductivity increases in the following order: H2S > SOF2 > SO2 > SO2F2. The limit of detection of the Ni-CNT Gas sensor reaches 1 ppm. In addition, the excellent recovery property of the Ni-CNT Gas sensor makes it easy to be widely used. A DFT theoretical study was applied to analyze the influence mechanism of Ni modification on SF6 decomposition components detection. In summary, the Ni-CNT Gas sensor prepared in this study can be an effective way to evaluate and diagnose the insulation status of SF6-insulated equipment online.
Sefaattin Tongay - One of the best experts on this subject based on the ideXlab platform.
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Highly efficient Gas Molecule-tunable few-layer Gase phototransistors
Journal of Materials Chemistry C, 2016Co-Authors: Shengxue Yang, Qu Yue, Hui Cai, Chengbao Jiang, Sefaattin TongayAbstract:Herein we present a systematic study on the effects of different Gas Molecules on the photoelectric response of few-layer Gase phototransistors before and after introducing defects.
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highly efficient Gas Molecule tunable few layer Gase phototransistors
Journal of Materials Chemistry C, 2016Co-Authors: Shengxue Yang, Qu Yue, Hui Cai, Chengbao Jiang, Sefaattin TongayAbstract:Herein we present a systematic study on the effects of different Gas Molecules on the photoelectric response of few-layer Gase phototransistors before and after introducing defects. After introducing defects by thermal annealing, the phototransistors become largely photo-responsive (18.75 A W−1) with high external quantum efficiency (EQE) (∼91.53%), high photocurrent on–off ratio, fast photo-response, and good stability in an O2 rich environment when illuminated by 254 nm ultraviolet light.
Qu Zhou - One of the best experts on this subject based on the ideXlab platform.
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Ni-CNT Chemical Sensor for SF6 Decomposition Components Detection: A Combined Experimental and Theoretical Study
Sensors, 2018Co-Authors: Xiaoxing Zhang, Peigeng Lv, Chao Tang, Shan Wang, Qu ZhouAbstract:SF6 decomposition components detection is a key technology to evaluate and diagnose the insulation status of SF6-insulated equipment online, especially when insulation defects-induced discharge occurs in equipment. In order to detect the type and concentration of SF6 decomposition components, a Ni-modified carbon nanotube (Ni-CNT) Gas sensor has been prepared to analyze its Gas sensitivity and selectivity to SF6 decomposition components based on an experimental and density functional theory (DFT) theoretical study. Experimental results show that a Ni-CNT Gas sensor presents an outstanding Gas sensing property according to the significant change of conductivity during the Gas Molecule adsorption. The conductivity increases in the following order: H2S > SOF2 > SO2 > SO2F2. The limit of detection of the Ni-CNT Gas sensor reaches 1 ppm. In addition, the excellent recovery property of the Ni-CNT Gas sensor makes it easy to be widely used. A DFT theoretical study was applied to analyze the influence mechanism of Ni modification on SF6 decomposition components detection. In summary, the Ni-CNT Gas sensor prepared in this study can be an effective way to evaluate and diagnose the insulation status of SF6-insulated equipment online.
Xianqi Dai - One of the best experts on this subject based on the ideXlab platform.
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A theoretical study on metal atom-modified BC 3 sheets for effects of Gas Molecule adsorptions
Applied Physics A, 2018Co-Authors: Yanan Tang, Weiguang Chen, Xiao Cui, Dalei Zhu, Huaduo Chai, Xianqi DaiAbstract:Based on the first-principle calculations, the chemical reactivity of transition metal (Fe, Co, Ni, and Cu) dopants within BC3 sheets toward toxic Gas Molecules (CO, NO, NO2, SO2, and HCN) is comparably investigated. First, the adsorbed Gases on metal-modified BC3 sheets exhibit the different stability. Compared with other Gases, the metal-modified BC3 substrates exhibit the stronger affinity toward the NO and NO2 Molecules (> 1.0 eV), while the adsorbed HCN has the smallest adsorption energy, illustrating that the NO and NO2 as specific toxic Gas Molecule can be easily detected. Second, the adsorbed Gas Molecules can effectively regulate the electronic structure and magnetic property of BC3 systems. Fox example, the strong adsorption of NO and NO2 on Fe-modified BC3 systems exhibits non-magnetic property, yet these Gases on Co modified BC3 systems exhibit the magnetic character. In addition, the adsorbed NO and SO2 can induce and turn the degree of magnetic moments of Ni- and Cu-modified BC3 systems. Therefore, the different kinds of adsorbed Gases on metal-modified BC3 sheets can be distinguished through investigating the changed magnetic moments of system, which would provide important information for designing the functional BC3-based materials.
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Structural, electronic, and magnetic properties of Gas Molecules on Mo-, Si-, and Pt-doped BC3 sheets
Journal of Physics and Chemistry of Solids, 2018Co-Authors: Yanan Tang, Weiguang Chen, Xiao Cui, Minghui Zhang, Xianqi DaiAbstract:Abstract In this study, based on first principles calculations, we compared the performance during the sensing of toxic Gas Molecules (NO, NO2, HCN, and NH3) by Mo, Si, and Pt dopants within BC3 sheets (D-BC3). Compared with the Pt-BC3 sheet, the Si-BC3 and Mo-BC3 sheets exhibit a stronger affinity for the adsorption of Gas Molecules. The adsorbed NO and HCN had larger energy differences than those of the NO2 and NH3 Molecules, thereby indicating that NO2 and NH3 could be detected readily as specific Gas Molecule on the D-BC3 substrates. In addition, the adsorption of Gas Molecules induced great changes in the electronic structure and magnetic properties of the D-BC3 systems. In particular, the adsorption of NO on the Pt-BC3 and Si-BC3 substrates yielded a larger magnetic moment (2.0 μB) than those when the other Gases were adsorbed on D-BC3 sheets. These results may facilitate control over the adsorption properties of toxic Gas Molecules and the design of BC3-based Gas sensors or spintronic devices.
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adsorption sensitivity of metal atom decorated bilayer graphene toward toxic Gas Molecules co no so2 and hcn
Sensors and Actuators B-chemical, 2017Co-Authors: Yanan Tang, Zhiyong Liu, Zigang Shen, Weiguang Chen, Xianqi DaiAbstract:Abstract Based on the first-principles calculations, the sensing performances of Fe embedded graphene sheets (including monolayer Fe-MG and bilayer Fe-BG) toward toxic Gases (NO, CO, HCN and SO2) are comparably investigated. Compared with the Fe-MG, the stable configuration of Fe-BG sheet exhibits the stronger affinity toward the Gas Molecules. The adsorbed NO has the largest energy difference between Fe-MG and Fe-BG substrate as compared with the other Gases, as well as inducing the change in electronic structure and magnetic property of Fe-graphene systems. In addition, the supported Pt(111) substrate can effectively regulate the strength of interaction between Gas Molecule and Fe-graphene substrates. As a result, the increased layer of graphene substrate can be utilizing as good sensor for toxic Gas Molecules, yet the metal Pt supported substrate can enhance the magnetic property of adsorbed Gas on the Fe-graphene systems. These results could provide important information for controlling the adsorption sensoring of Gas Molecules, which opens up a new avenue for the design and fabrication of the graphene-based Gas sensors or spintronic devices.
Christopher J Hogan - One of the best experts on this subject based on the ideXlab platform.
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Gas Molecule scattering & ion mobility measurements for organic macro-ions in He versus N2 environments
Physical chemistry chemical physics : PCCP, 2015Co-Authors: Carlos Larriba-andaluz, Christopher J Hogan, Juan Fernández-garcía, Michael A. Ewing, David E. ClemmerAbstract:A pending issue in linking ion mobility measurements to ion structures is that the collisional cross section (CCS, the measured structural parameter in ion mobility spectrometry) of an ion is strongly dependent upon the manner in which Gas Molecules effectively impinge on and are reemitted from ion surfaces (when modeling ions as fixed structures). To directly examine the Gas Molecule impingement and reemission processes and their influence, we measured the CCSs of positively charged ions of room temperature ionic liquids 1-ethyl-3-methylimidazolium dicyanamide (EMIM-N(CN)2) and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) in N2 using a differential mobility analyzer-mass spectrometer (DMA-MS) and in He using a drift tube mobility spectrometer-mass spectrometer (DT-MS). Cluster ions, generated via electrosprays, took the form (AB)N(A)z, spanning up to z = 20 and with masses greater than 100 kDa. As confirmed by molecular dynamics simulations, at the measurement temperature (∼300 K), such cluster ions took on globular conformations in the Gas phase. Based upon their attained charge levels, in neither He nor N2 did the ion-induced dipole potential significantly influence Gas Molecule-ion collisions. Therefore, differences in the CCSs measured for ions in the two different Gases could be primarily attributed to differences in Gas Molecule behavior upon collision with ions. Overwhelmingly, by comparison of predicted CCSs with selected input impingement-reemission laws to measurements, we find that in N2, Gas Molecules collide with ions diffusely--they are reemitted at random angles relative to the Gas Molecule incoming angle--and inelastically. Meanwhile, in He, Gas Molecules collide specularly and elastically and are emitted from ion surfaces at determined angles. The results can be rationalized on the basis of the momentum transferred per collision; in the case of He, individual Gas Molecule collisions minimally perturb the atoms within a cluster ion (internal motion), while in the case of N2, individual Gas Molecules have sufficiently large momentum to alter the internal motion in organic ions.
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Gas Molecule scattering ion mobility measurements for organic macro ions in he versus n2 environments
Physical Chemistry Chemical Physics, 2015Co-Authors: Carlos Larribaandaluz, Christopher J Hogan, Michael A. Ewing, Juan Fernandezgarcia, David E. ClemmerAbstract:A pending issue in linking ion mobility measurements to ion structures is that the collisional cross section (CCS, the measured structural parameter in ion mobility spectrometry) of an ion is strongly dependent upon the manner in which Gas Molecules effectively impinge on and are reemitted from ion surfaces (when modeling ions as fixed structures). To directly examine the Gas Molecule impingement and reemission processes and their influence, we measured the CCSs of positively charged ions of room temperature ionic liquids 1-ethyl-3-methylimidazolium dicyanamide (EMIM-N(CN)2) and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4) in N2 using a differential mobility analyzer-mass spectrometer (DMA-MS) and in He using a drift tube mobility spectrometer-mass spectrometer (DT-MS). Cluster ions, generated via electrosprays, took the form (AB)N(A)z, spanning up to z = 20 and with masses greater than 100 kDa. As confirmed by molecular dynamics simulations, at the measurement temperature (∼300 K), such cluster ions took on globular conformations in the Gas phase. Based upon their attained charge levels, in neither He nor N2 did the ion-induced dipole potential significantly influence Gas Molecule–ion collisions. Therefore, differences in the CCSs measured for ions in the two different Gases could be primarily attributed to differences in Gas Molecule behavior upon collision with ions. Overwhelmingly, by comparison of predicted CCSs with selected input impingement–reemission laws to measurements, we find that in N2, Gas Molecules collide with ions diffusely – they are reemitted at random angles relative to the Gas Molecule incoming angle – and inelastically. Meanwhile, in He, Gas Molecules collide specularly and elastically and are emitted from ion surfaces at determined angles. The results can be rationalized on the basis of the momentum transferred per collision; in the case of He, individual Gas Molecule collisions minimally perturb the atoms within a cluster ion (internal motion), while in the case of N2, individual Gas Molecules have sufficiently large momentum to alter the internal motion in organic ions.
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Collision cross section calculations for polyatomic ions considering rotating diatomic/linear Gas Molecules.
The Journal of chemical physics, 2014Co-Authors: Carlos Larriba-andaluz, Christopher J HoganAbstract:Structural characterization of ions in the Gas phase is facilitated by measurement of ion collision cross sections (CCS) using techniques such as ion mobility spectrometry. Further information is gained from CCS measurement when comparison is made between measurements and accurately predicted CCSs for model ion structures and the Gas in which measurements are made. While diatomic Gases, namely molecular nitrogen and air, are being used in CCS measurement with increasingly prevalency, the majority of studies in which measurements are compared to predictions use models in which Gas Molecules are spherical or non-rotating, which is not necessarily appropriate for diatomic Gases. Here, we adapt a momentum transfer based CCS calculation approach to consider rotating, diatomic Gas Molecule collisions with polyatomic ions, and compare CCS predictions with a diatomic Gas Molecule to those made with a spherical Gas molecular for model spherical ions, tetra-alkylammonium ions, and multiply charged polyethylene glycol ions. CCS calculations are performed using both specular-elastic and diffuse-inelastic collisions rules, which mimic negligible internal energy exchange and complete thermal accommodation, respectively, between Gas Molecule and ion. The influence of the long range ion-induced dipole potential on calculations is also examined with both Gas Molecule models. In large part we find that CCSs calculated with specular-elastic collision rules decrease, while they increase with diffuse-inelastic collision rules when using diatomic Gas Molecules. Results clearly show the structural model of both the ion and Gas Molecule, the potential energy field between ion and Gas Molecule, and finally the modeled degree of kinetic energy exchange between ion and Gas Molecule internal energy are coupled to one another in CCS calculations, and must be considered carefully to obtain results which agree with measurements.
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free molecular collision cross section calculation methods for nanoparticles and complex ions with energy accommodation
Journal of Computational Physics, 2013Co-Authors: Carlos Larriba, Christopher J HoganAbstract:The structures of nanoparticles, macroMolecules, and molecular clusters in Gas phase environments are often studied via measurement of collision cross sections. To directly compare structure models to measurements, it is hence necessary to have computational techniques available to calculate the collision cross sections of structural models under conditions matching measurements. However, presently available collision cross section methods contain the underlying assumption that collision between Gas Molecules and structures are completely elastic (Gas Molecule translational energy conserving) and specular, while experimental evidence suggests that in the most commonly used background Gases for measurements, air and molecular nitrogen, Gas Molecule reemission is largely inelastic (with exchange of energy between vibrational, rotational, and translational modes) and should be treated as diffuse in computations with fixed structural models. In this work, we describe computational techniques to predict the free molecular collision cross sections for fixed structural models of Gas phase entities where inelastic and non-specular Gas Molecule reemission rules can be invoked, and the long range ion-induced dipole (polarization) potential between Gas Molecules and a charged entity can be considered. Specifically, two calculation procedures are described detail: a diffuse hard sphere scattering (DHSS) method, in which structures are modeled as hard spheres and collision cross sections are calculated for rectilinear trajectories of Gas Molecules, and a diffuse trajectory method (DTM), in which the assumption of rectilinear trajectories is relaxed and the ion-induced dipole potential is considered. Collision cross section calculations using the DHSS and DTM methods are performed on spheres, models of quasifractal aggregates of varying fractal dimension, and fullerene like structures. Techniques to accelerate DTM calculations by assessing the contribution of grazing Gas Molecule collisions (Gas Molecules with altered trajectories by the potential interaction) without tracking grazing trajectories are further discussed. The presented calculation techniques should enable more accurate collision cross section predictions under experimentally relevant conditions than pre-existing approaches, and should enhance the ability of collision cross section measurement schemes to discern the structures of Gas phase entities.
