Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

Structural, Electronic and Optical Properties of ScxAl1-xN alloys within DFT Calculations

Structural, electronic and optical properties of Sc-based aluminum-nitride alloy have been carried out with first-principles methods using both local density approximation (LDA) and Heyd-Scuseria-Ernzerhof (HSE) hybrid functional. This latter provides a more accurate description of the lattice parameters, enthalpy of formation, electronic and optical properties of our alloy than standard DFT. We found the transition from wurtzite to rocksalt structures at 61% of Sc concentration. By increasing the scandium concentration, the lattice parameters and the band gap decrease. The HSE band gap is in good agreement with available experimental data. The existence of the strong hybridization between Sc 3d and N 2p indicates the transport of electrons from Sc to N atoms. Besides, it is shown that the insertion of the Sc atom leads to the redshift of the optical absorption edge. The optical absorption of ScxAl1-xN is found to decrease with increasing Sc concentrations in the low energy range. Because of this, ScxAl1-xN have a great potential for applications in photovoltaics and photocatalysis.

A Hybrid Approach to Modeling and Control of Vehicle Height for Electronically Controlled Air Suspension

The control problems associated with vehicle height adjustment of electronically controlled air suspension （ECAS） still pose theoretical challenges for researchers, which manifest themselves in the publications on this subject over the last years. This paper deals with modeling and control of a vehicle height adjustment system for ECAS, which is an example of a hybrid dynamical system due to the coexistence and coupling of continuous variables and discrete events. A mixed logical dynamical （MLD） modeling approach is chosen for capturing enough details of the vehicle height adjustment process. The hybrid dynamic model is constructed on the basis of some assumptions and piecewise linear approximation for components nonlinearities. Then, the on-off statuses of solenoid valves and the piecewise approximation process are described by propositional logic, and the hybrid system is transformed into the set of linear mixed-integer equalities and inequalities, denoted as MLD model, automatically by HYSDEL. Using this model, a hybrid model predictive controller （HMPC） is tuned based on online mixed-integer quadratic optimization （MIQP）. Two different scenarios are considered in the simulation, whose results verify the height adjustment effectiveness of the proposed approach. Explicit solutions of the controller are computed to control the vehicle height adjustment system in realtime using an offline multi-parametric programming technology （MPT）, thus convert the controller into an equivalent explicit piecewise affine form. Finally, bench experiments for vehicle height lifting, holding and lowering procedures are conducted, which demonstrate that the HMPC can adjust the vehicle height by controlling the on-off statuses of solenoid valves directly. This research proposes a new modeling and control method for vehicle height adjustment of ECAS, which leads to a closed-loop system with favorable dynamical properties.

Research on power electronic transformer applied in AC/DC hybrid distribution networks

The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/DC hybrid distribution network is put forward according to the demands of power grid, with advantages of accepting DG and DC loads, while clearing DC fault by blocking the clamping double sub-module(CDSM) of input stage. Then, this paper shows the typical structure of AC/DC distribution network that is hand in hand. Based on the new topology, this paper designs the control and modulation strategies of each stage, where the outer loop controller of input stage is emphasized for its twocontrol mode. At last, the rationality of new topology and the validity of control strategies are verified by the steady and dynamic state simulation. At the same time, the simulation results highlight the role of PET in energy regulation.

A Numerical Convex Lens for the State-Discretized Modeling and Simulation of Megawatt Power Electronics Systems as Generalized Hybrid Systems

Modeling and simulation have emerged as an indispensable approach to create numerical experiment platforms and study engineering systems.However,the increasingly complicated systems that engineers face today dramatically challenge state-of-the-art modeling and simulation approaches.Such complicated systems,which are composed of not only continuous states but also discrete events,and which contain complex dynamics across multiple timescales,are defined as generalized hybrid systems(GHSs)in this paper.As a representative GHS,megawatt power electronics(MPE)systems have been largely integrated into the modern power grid,but MPE simulation remains a bottleneck due to its unacceptable time cost and poor convergence.To address this challenge,this paper proposes the numerical convex lens approach to achieve state-discretized modeling and simulation of GHSs.This approach transforms conventional time-discretized passive simulations designed for pure-continuous systems into state-discretized selective simulations designed for GHSs.When this approach was applied to a largescale MPE-based renewable energy system,a 1000-fold increase in simulation speed was achieved,in comparison with existing software.Furthermore,the proposed approach uniquely enables the switching transient simulation of a largescale megawatt system with high accuracy,compared with experimental results,and with no convergence concerns.The numerical convex lens approach leads to the highly efficient simulation of intricate GHSs across multiple timescales,and thus significantly extends engineers’capability to study systems with numerical experiments.

A HYBRID ELECTRONIC NOSES’SYSTEM BASED ON MOS-SAW DETECTION UNITS INTENDED FOR LUNG CANCER DIAGNOSIS

In this paper,a hybrid electronic noses’system(HENS)based on MOS-SAW detection units intended for lung cancer diagnosis is proposed.The MOS gas sensors are used to detect the VOC molecules with low molecular weight(LMW),and the SAW sensors are adopted for the detection of VOC with high molecular weight(HMW).Thus,the novel combination of these two kinds of gas sensors provides higher sensitivities to more of VOC species in breath than that of using only a single kind of sensor.The signals from MOS-SAW detection units are then recognized by a multi-model diagnosis method.Applying four algorithms,six models were established for diagnosis and tested by leave-one-out cross-validation method.The model by artificial neural network(ANN)was selected as the best model to analyze breath samples.89 clinical samples were tested with MOS-SAW ANN diagnostic model,which takes the features derived from both the MOS and SAW sensors.It shows the highest sensitivity of 93.62%,and the highest selectivity of 83.37%.The study shows that,promisingly,our HENS is effective during screening of lung cancer patients,especially among the people of high risk.

The front-end electronics design of dose monitors for beam delivery system of Shanghai Advanced Proton Therapy Facility

A front-end electronics of dose monitor has been developed for measuring irradiation dose to the patient in Shanghai Advanced Proton Therapy Facility.The parallel plate ionization chamber is used for the dose monitoring.Unlike the traditional method of recycling capacitor integration and voltage-to-frequency conversion,this dose monitor electronics uses the trans-impedance amplifier and analog-to-digital conversion method.It performs satisfactorily,with the integral nonlinearity of less than ±0.04 nA in the range of-400 to 50 nA and the resolution of about±0.6 nA.

Morphology and Electronic Properties of Hybrid Organic-Inorganic System: Ag Nanoparticles Embedded into CuPc Matrix

Materials with a high on-off resistance ratio could become the basis for resistive random-access memory (RRAM). It is assumed that one of RRAM types can be based on hybrid organic-inorganic systems, while particular attention is focused on hybrid systems consisting of metal nanoparticles (NP) embedded in organic matrix (OM). In this investigation we created and studied the hybrid organic-inorganic systems made of metal (Ag) nanoparticles embedded in organic semiconductor material CuPc. The LEED patterns and NEXAFS data demonstrate that the CuPc films deposited on Au(001) substrate are highly ordered and molecular planes lie parallel to the gold surface. The metal atoms were deposited on the outer surface of the organic molecular film and self-assembled into nanoparticles due to surface and bulk diffusion. The properties of nano-composite materials seem to be significantly dependent on the microstructure, i.e. the size, concentration, bulk- and size-distribution of nanoparticles;therefore we have studied by high resolution transmission electron microscopy the evolution of morphology of nano-composite films as a function of nominal metal deposition. The filled and empty electronic states of the hybrid organic-inorganic systems, energy level alignment at interfaces formed between metal nanoparticles and the organic semiconductor CuPc as well as the chemical interaction at the NP/OM interface were studied by UPS, XPS and NEXAFS methods.

Hybrid ionic/electronic interphase enabling uniform nucleation and fast diffusion kinetics for stable lithium metal anode

Lithium(Li)dendrite issue,which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase(SEI),impedes the further development of high-energy Li metal batteries.However,the integrated construction of a high-stable SEI layer that can regulate uniform nucleation and facilitate fast Li-ion diffusion kinetics for Li metal anode still falls short.Herein,we designed an artificial SEI with hybrid ionic/electronic interphase to regulate Li deposition by in-situ constructing metal Co clusters embedded in LiF matrix.The generated Co and LiF both enable fast Li-ion diffusion kinetics,meanwhile,the lithiophilic properties of Co clusters can serve as Li-ion nucleation sites,thereby contributing to uniform Li nucleation and non-dendritic growth.As a result,a dendrite-free Li deposition with a low overpotential(16.1 mV)is achieved,which enables an extended lifespan over 750 h under strict conditions.The full cells with high-mass-loading LiFePO_(4)(11.5 mg/cm^(2))as cathodes exhibit a remarkable rate capacity of 84.1 mAh/g at 5 C and an improved cycling performance with a capacity retention of 96.4%after undergoing 180 cycles.

Preparation and Conducting Behavior of Amphibious Organic/Inorganic Hybrid Proton Exchange Membranes Based on Benzyltetrazole

A series of novel amphibious organic/inorganic hybrid proton exchange membranes with H3PO4 doped which could be used under both wet and dry conditions was prepared through a sol-gel process based on acrylated triethoxysilane（A-TES） and benzyltetrazole-modified triethoxysilane（BT-TES）.The dual-curing approach including UV-curing and thermal curing was used to obtain the crosslinked membranes.Polyethylene glycol（400） diacrylate（PEGDA） was used as an oligomer to form the polymeric matrix.The molecular structures of precursors were characterized by 1 H,13 C and 29 Si NMR spectra.The thermogravimetric analysis（TGA） results show that the membranes exhibit acceptable thermal stability for their application at above 200 oC.The differential scanning calorimeter（DSC） determination indicates that the crosslinked membranes with the mass ratios of below 1.6 of BT-TES to A-TES and the same mass of H3PO4 doped as that of A-TES possess the-T g s,and the lowest T g（-28.9 ℃） exists for the membrane with double mass of H3PO4 doped as well.The high proton conductivity in a range of 9.4―17.3 mS/cm with the corresponding water uptake of 19.1%―32.8% of the membranes was detected at 90 oC under wet conditions.Meanwhile,the proton conductivity in a dry environment for the membrane with a mass ratio of 2.4 of BT-TES to A-TES and double H3PO4 loading increases from 4.89×10-2 mS/cm at 30 ℃ to 25.7 mS/cm at 140 ℃.The excellent proton transport ability under both hydrous and anhydrous conditions demonstrates a potential application in the polymer electrolyte membrane fuel cells.

Electronic and optical properties of lithium niobate under high pressure: A first-principles study

We theoretically study the structural, electronic, and optical properties of lithium niobate under pressure using the plane-wave pseudopotential density functional theory by CASTEP code. It was found that there is a phase transition from the R3 c structure to the Pnma structure at a pressure of 18.7 GPa. The Pnma structure was dynamically stable according to the calculation of phonon dispersion. From the charge density distributions, there exist covalent interactions along the Nb–O bond. The hybridization between O 2p and Nb 4d orbital in the Pnma phase increases with increasing pressure, while it is not changed in the R3c phase. With increasing pressure, the average Nb–O bond length decreases and the Nb–O bond population increases, indicating the increased covalent character between Nb and O atoms under high pressure at Pnma phase, which leads to the increased hybridization between O 2p and Nb 4d orbitals. Furthermore, the optical dielectric function, refractive index, extinction coefficient, electron energy, loss and reflectivity are calculated.

Optimized calculation of the synergy conditions between electron cyclotron current drive and lower hybrid current drive on EAST

The optimized synergy conditions between electron cyclotron current drive （ECCD） and lower hybrid current drive （LHCD） with normal parameters of the EAST tokamak are studied by using the C3PO/LUKE code based on the under- standing of the synergy mechanisms so as to obtain a higher synergistic current and provide theoretical reference for the synergistic effect in the EAST experiment. The dependences of the synergistic effect on the parameters of two waves （lower hybrid wave （LHW） and electron cyclotron wave （ECW））, including the radial position of the power deposition, the power value of the LH and EC waves, and the parallel refractive indices of the LHW （Nr） are oresented and discussed.

Analysis of the decrease of two-dimensional electron gas concentration in GaN-based HEMT caused by proton irradiation

Gallium nitride(Ga N)-based high electron mobility transistors(HEMTs)that work in aerospace are exposed to particles radiation,which can cause the degradation in electrical performance.We investigate the effect of proton irradiation on the concentration of two-dimensional electron gas(2 DEG)in Ga N-based HEMTs.Coupled Schr¨odinger’s and Poisson’s equations are solved to calculate the band structure and the concentration of 2 DEG by the self-consistency method,in which the vacancies caused by proton irradiation are taken into account.Proton irradiation simulation for Ga N-based HEMT is carried out using the stopping and range of ions in matter(SRIM)simulation software,after which a theoretical model is established to analyze how proton irradiation affects the concentration of 2 DEG.Irradiated by protons with high fluence and low energy,a large number of Ga vacancies appear inside the device.The results indicate that the ionized Ga vacancies in the Ga N cap layer and the Al Ga N layer will affect the Fermi level,while the Ga vacancies in the Ga N layer will trap the two-dimensional electrons in the potential well.Proton irradiation significantly reduced the concentration of 2 DEG by the combined effect of these two mechanisms.

The Phenomenon of Proton Dissolving in Vacuum and of Proton Condensation from Vacuum. Two Forms of Protons, Structure of Nuclei, Electrons and Atoms

It was investigated how react molecular clusters in water, starch, bio-matrices, polymers and in quartz on gravitation radiation from planets. Gravitation radiation (GR) was found to influence the proton jumping in hydrogen bonds that stabilize the cluster structure. There was given a method calculating parameters of GR as well as a mechanism of its resonance interaction with weak GR from molecular matter (WGR). WGR has been defined as the result of proton dissolving in vacuum connected with its simultaneous condensation in the nearest free space. Both dissolving and condensation proceed with super light velocity. The gravitation wave length has been determined experimentally and it depends on the planet masses (between Earth and Sun λ ≥ 62 km, between Earth and Milky Way center λ ≥ 330 km). GR has been characterized with super light velocity. After analyzing the Sun influence on water two forms of protons were found: in a condensed and dissolved state. A new model for the atomic nucleus has been suggested according to which the protons in the nucleus oscillate between condensed and dissolved state, where in the case of isotopes this state is partially destroyed. The models for H2 and Be shall be given. Electron orbitals in atoms and molecules were found to be caused by a stationary front of shock waves from condensing protons.

Performance of Ti6Al4V fabricated by electron beam and laser hybrid preheating and selective melting strategy

Electron beam selective melting(EBM)and selective laser melting(SLM)are regarded as significant manufacturing processes for near-net-shaped Ti6Al4V components.Generally,in the conventional EBM process,preheating is necessitated to avoid"smoke"caused by the charging of electrons.In the conventional SLM process,laser as an energy source without the risk of"smoke"can be employed to melt metal powder at low temperatures.However,because of the low absorption rate of laser,the powder bed temperature cannot reach a high level.It is difficult to obtain as-built TiAl4V with favorable comprehensive properties via conventional EBM or SLM.Hence,two types of electron beam and laser hybrid preheating(EB-LHP)combined with selective melting strategies are proposed.Using laser to preheat powder allows EBM to be performed at a low powder bed temperature(EBM-LT),whereas using an electron beam to preheat powder allows SLM to be performed at a high powder bed temperature(SLM-HT).Ti6Al4V samples are fabricated using two different manufacturing strategies(i.e.,EBM-LT and SLM-HT)and two conventional processes,i.e.,EBM at a high powder bed temperature(EBM-HT)and SLM at a low powder bed temperature(SLM-LT).The temperature-dependent surface quality,microstructure,density,and mechanical properties of the as-built Ti6Al4V samples are characterized and compared.Results show that EBM-LT Ti6Al4V exhibits a higher ultimate tensile strength(981±43 MPa)and a lower elongation(12.2%±2.3%)than EBM-HT Ti6Al4V owing to the presence ofα′martensite.The SLM-HT Ti6Al4V possesses the highest ultimate tensile strength(1,059±62 MPa)and an elongation(14.8%±4.0%)comparable to that of the EBM-HT Ti6Al4V(16.6%±1.2%).

Theoretical Studies on Electronic Spectrum Property of 2-(2-Hydroxyphenyl)pyridine Via Time-dependence Density Functional Theory Method

The geometrical structures of 2 (2 hydroxyphenyl) pyridine(PP) and its protonation states were optimized by means of the B3LYP/6 31G(d) method. For all the selected systems, the existence of H bond is in favor of the stability of the systems. On the basis of the optimized geometrical structures, their electronic spectrum properties were studied by time dependent density functional theory(TD DFT) methosd via a hybrid function of B3LYP and 6 31G(d) basis set. The TD DFT calculation result predicts the absorption spectrum of PP at 324 nm(3.82 eV), which is in very good agreement with the experimental value of 322 nm( 3.85 eV ) determined in solvent chloroform. The absorption spectra of the two protonation states both exert a red shift in various pH media.

Electronic Structure and Optical Properties of LiBiO3 Doped with V,Nb,and Ta

The crystal structure, band structure, density of states, Mulliken charge, bond population and optical properties for LiBi_（1-x）M_xO_3（M=V, Nb, and Ta） were investigated using hybrid density functional theory. It was found that LiBiO_3 doped with V, Nb, and Ta presented distinctly stronger covalent interactions in M-O（M=V, Nb, and Ta） than Bi-O, thus resulting in mild distortion of the structure and facilitating the separation of photogenerated carriers. Furthermore, the hybridizations of Bi-6s, M-d（M=V, Nb, and Ta） and O-2p widened the valence and conduction bands, which promoted transmission of photogenerated carriers in the band edge and thus caused better photocatalytic performance.

DISTRIBUTION OF VEGF mRNA IN BREAST CANCER WITH NONRADIOACTIVE IN SITU HYBRIDIZATION AT ELECTRON MICROSCOPIC LEVELS

Object: To localize the mRNA coding for VEGF at Ultrastractural level in human breast cancer by using digoxigenin-labeled cDNA probes. Methods: Nonradioactive in situ hybridization at electron microscopic level was employed to detected VEGF mRNA in breast cancer. Result: Cancer cells and endothelial cell of angiogensis show dark color in experiment sections. No dark color can be found in control sections. Positive hybridization signals showed dark dot and were located in various compartments of the breast cancer cell and endothelial cell in experiment section. No labeling was observed in control sections. In experiment sections, the staining appeared concentrated in cytoplasm and nucleus of the breast cancer cell and endothelial cell. Conclusion: Nonradioactive in situ hybridization at electron microscopic level is efficient for direct observation of the target site mRNA of VEGF in the cytoplasm and nucleus.