Unraveling the Stray Current-Induced Interfacial Transition Zone(ITZ)Effect on Sulfate Corrosion in Concrete

The rail transit in sulfate-rich areas faces the combined effects of stray current and salt corrosion;however,the sulfate ion transport and concrete degradation mechanisms under such conditions are still unclear.To address this issue,novel sulfate transport and mesoscale splitting tests were designed,with a focus on considering the differences between the interfacial transition zone(ITZ)and cement matrix.Under the influence of stray current,the ITZ played a pivotal role in regulating the transport and mechanical failure processes of sulfate attack,while the tortuous and blocking effects of aggregates almost disappeared.This phenomenon was termed the“stray current-induced ITZ effect.”The experimental data revealed that the difference in sulfate ion transport attributed to the ITZ ranged from 1.90 to 2.31 times,while the difference in splitting strength ranged from 1.56 to 1.64 times.Through the real-time synchronization of splitting experiments and microsecond-responsive particle image velocimetry(PIV)technology,the mechanical properties were exposed to the consequences of the stray currentinduced ITZ effect.The number of splitting cracks in the concrete increased,rather than along the central axis,which was significantly different from the conditions without stray current and the ideal Brazilian disk test.Furthermore,a sulfate ion mass transfer model that incorporates reactivity and electrodiffusion was meticulously constructed.The embedded finite element calculation exhibited excellent agreement with the experimental results,indicating its reliability and accuracy.Additionally,the stress field was determined utilizing analytical methods,and the mechanism underlying crack propagation was successfully obtained.Compared to the cement matrix,a stray current led to more sulfates,more microstructure degradation,and greater increases in thickness and porosity in the ITZ,which was considered to be the essence of the stray current-induced ITZ effect.

New finite strain elastoplastic equations for accurately and explicitly simulating pseudoelastic-to-plastic transition effects of shape memory alloys

A new finite strain elatoplastic J2-flow model with coupling effects of both isotropic and anisotropic hardening is proposed with the co-rotational logarithmic rate.In terms of certain single-variable shape functions representing uniaxial loading and unloading curves,explicit multi-axial expressions for the three hardening quantities incorporated in the new model proposed are derived in unified forms for the purpose of automatically and accurately simulating complex pseudoelastic-to-plastic transition effects of shape memory alloys(SMAs)under multiple loading-unloading cycles.Numerical examples show that with only a single parameter of direct physical meaning for each cycle,accurate and explicit simulations may be achieved for extensive data from multiple cycle tests.

Effects of Reduced Frequency on Network Configuration and Synchronization Transition

Synchronization of networked phase oscillators depends essentially on the correlation between the topological structure of the graph and the dynamical property of the elements. We propose the concept of ＇reduced frequency＇, a measure which can quantify natural frequencies of each pair of oscillators. Then we introduce an evolving network whose linking rules are controlled by its own dynamical property. The simulation results indicate that when the linking probability positively correlates with the reduced frequency, the network undergoes a first-order phase transition. Meanwhile, we discuss the circumstance under which an explosive synchronization can be ignited. The numerical results show that the peculiar butterfly shape correlation between frequencies and degrees of the nodes contributes to an explosive synchronization transition.

Effect of Carbon on the Paramagnetic-Antiferromagnetic Transition and γ→εMartensitic Transformation of Fe-24Mn Alloys

The effect of C content (0.014-0.39 wt pct) on the paramagnetic-antiferromagnetic transition and γ→ε martensitic transformation of Fe-24Mn alloys has been investigated by the resistivity, dilation, tensile properties measurement and microstructure examination. The results have shown that C decreases T_N; increases the thermal expansion coefficients both above and below the T_N; increases the resistivity above the T_N and antiferromagnetic scattering resistivity below T_N. It strongly depresses the γ→ε martensitic transformation and reduces the M_s of Fe-24Mn alloys. Moreover, it increases the lattice parameter of austenite, enhances the tensile ductility, but almost does not affect the tensile strength. With increasing C content from 0.014 to 0.19 wt pct, the yield strength of Fe-24Mn alloy decreases obviously arising from the decreasing of preexisting ε martensite. but it increases from 0.19 to 0.39 wt pct C due to the solution hardening of C.

Giant Volume Magnetostriction Caused by Itinerant Electron Metamagnetic Transition and Pronounced Invar Effects in La(Fe_xSi_(1-x))_(13) Compounds

A first-order itinerant electron metamagnetic (IEM) transition above the Curie temperature Tc for ferromagnetic La(Fe_xSi_1-x)13 compounds has been confirmed by applying magnetic field. The volume change just above T_C for x=0.88 is huge of about 1.5%, which is caused by a large magnetic moment induced by the IEM transition. These compounds have a possibility for practical applications as giant magnetostrictive materials. Pronounced Invar effects bring about a negative thermal expansion below TC, closely correlated with the negative mode-mode coupling among spin fluctuations.

Transition and self-sustained turbulence in dilute suspensions of finite-size particles

We study the transition to turbulence of channel flow of finite-size particle suspensions at low volume fraction, i.e., φ ≈0.001. The critical Reynolds number above which turbulence is sustained reduces to Re ≈ 1675, in the presence of few particles, independently of the initial condition, a value lower than that of the corresponding single-phase flow, i.e., Re ≈1775. In the dilute suspension, the initial arrangement of the particles is important to trigger the transition at a fixed Reynolds number and particle volume fraction. As in single phase flows, streamwise elongated disturbances are initially induced in the flow. If particles can induce oblique disturbances with high enough energy within a certain time, the streaks breakdown, flow experiences the transition to turbulence and the particle trajectories become chaotic, Otherwise, the streaks decay in time and the particles immigrate towards the channel core in a laminar flow.

Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part I: LiMn_2O_4 and LiCo_(0.5)Ni_(0.5)O_2

Electrochemical insertion/extraction of Li on cathode materials of spinel type LiMn2O4 and ordered rock-salt type LiCo0.5 Ni0.5O2 was measured on samples of which structures were well characterized. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materiaIs on electrochemical Li insertion/extraction performance was discussed. These two transition metal oxides belong to onegroup that the crystallinity of these oxides affects to the performance.

Effect of Crystallinity on Electrochemical Insertion/Extraction of Li in Transition Metal Oxides Part Ⅱ: TiO_2, V_2O_5 and MoO_3

Electrochemical insertion/extraction of Li on cathode materials of anatase type TiO_2, quasilayered structure V_2O_5 and layered structure MoO_3 was measured on samples of which structures were well characterized and showed a wide range of crystallinity. On the basis of experimental results on structure, morphology and charge-discharge characteristics, the effect of crystallinity of the cathode materials on electrochemical Li insertion/extraction pedermance was discussed. These three transition metal oxides were classified as one group on the basis of whether the crystallinity of these oxides affects to the performance or not; LiMn_2O_4 and LiCo_(0.5)O_2 belongs to the former group and TiO_2, V_2O_5 and MoO_3 to the latter.

Transition Effects from the Initial Adoption of IFRS 9 by Italian and German Blue Chip Companies

For the financial years from 2018,the new standard for accounting of financial instruments,IFRS 9,was applicable for the first time.Various questions arose in connection with the transition.For example,how high would the resulting transition effect be on equity?Another aspect related to the question of the extent to which the fair value measurement(through profit or loss)would increase.It is also of interest whether the previously presented IFRS 9 changes are classifiable as being material.Through the analysis of the financial statements of FTSE MIB and DAX 30 companies that were prepared for the first time in accordance with IFRS 9 in the year 2018,answers are given in this article to the aforementioned questions and a comparison is made regarding the extent to which national differences or commonalities existed.In the overall view of the absolute change in equity,for the FTSE MIB companies,a mean value of€-3.03 million was calculated and for the DAX 30 companies,€-34.29 million.The equity ratio(median),however,only declined marginally in percentage points with the FTSE MIB companies(-0.07),as well as with the DAX 30 companies(-0.02).With regard to the migration of financial assets,it has been shown that the accounting and measurement of more than 90%of financial assets of the FTSE MIB and DAX 30 companies have not changed.With the rest,the measurement net at fair value(through profit or loss)increased in both stock exchange segments.Nearly all changes to equity,the FTSE MIB,as well as DAX 30 companies,can be classified as immaterial.The extent to which the expansion of the measurement of financial instruments,which are measured at the fair value(through profit or loss)can be material,will ultimately depend on the individual case,in view of the future IFRS financial statements.This then depends on how high the actual change in fair value(through profit or loss)of these holdings is in a period in an individual case,in absolute and relative terms—for example,in proportion to the equity and the P&L.The latter also applies to FTSE MIB,as well as DAX 30 companies.

Novel 0–π transitions in Josephson junctions between noncentrosymmetric superconductors

We study the Josephson effect between two noncentrosymmetric superconductors（NCSs） with opposite polarization vectors of Rashba spin–orbit coupling（RSOC）.We find a 0–π transition driven by the triplet–singlet ratio of NCSs.Different from conventional 0–π transitions,the Andreev bound states change their energy range instead of phase shift in the 0–π transition found here.This novel property results in a feature that the critical current becomes almost zero at the transition point,not only a minimum.Furthermore,when the directions of RSOC polarization vectors are the same in two NCSs,the similar effect can also be found in the presence of a perpendicular exchange field or a Dresselhause spin–orbit coupling in the interlayer.We find novel oscillations of critical current without 0–π transition.These novel 0–π transitions or oscillations of critical current present new understanding of the Josephson effect and can also serve as a tool to determine the unknown triplet–singlet ratio of NCSs.

Strain-induced insulator–metal transition in ferroelectric BaTiO_3(001) surface:First-principles study

The electronic properties of TiO2-terminated BaTiO3（001） surface subjected to biaxial strain have been studied using first-principles calculations based on density functional theory. The Ti ions are always inward shifted either at compressive or tension strains, while the inward shift of the Ba ions occurs only for high compressive strain, implying an enhanced electric dipole moment in the case of high compressive strain. In particular, an insulator–metal transition is predicted at a compressive biaxial strain of 0.0475. These changes present a very interesting possibility for engineering the electronic properties of ferroelectric BaTiO3（001） surface.

Voltage-controlled Kosterlitz–Thouless transitions and various kinds of Kondo behaviors in a triple dot device

The transport property and phase transition for a parallel triple dot device are studied by adopting Wilson＇s numerical renormalization group technique, focusing on the effects of level spacings between neighboring dot sites. By keeping dot 2at the half-filled level and tuning the level differences, it is demonstrated that the system transits from local spin quadruplet to triplet and doublet sequently, and three kinds of Kondo peaks at the Fermi surface could be found, which are separated by two Kosterlitz–Thouless type quantum phase transitions and correspond to spin-3/2, spin-1, and spin-1/2 Kondo effect,respectively. To obtain a detailed understanding of these problems, the charge occupation, the spin–spin correlation, the transmission coefficient, and the temperature-dependent magnetic moment are shown, and necessary physical arguments are given.

Studies of Anomalies in Mixed Conduction of Na2O and V2O5 Doped Boro-Phosphate Glasses

A set of borophosphate glasses doped with alkali and transition metal (TM) ions have been synthesized. The glasses were carried through;annealing, XRD, density, DC conductivity studies. Molar volume and density varied nonlinearly. High temperature activation energy is analysed taking into consideration of Mott’s SPH model. The low temperature electrical conductivity was analysed by Mott and Greaves VRH. Several polaron hopping related parameters at high temperature region and density of states at low temperature region were computed. The high temperature DC activation energy measured by conductivity, calculated numerous pertained parameters varied nonlinearly with mole fraction of vanadium content. The Study exhibits DC electrical conduction is due to both alkali and transition metal ions and thus confirms the mixed conductivity. A crossover conduction mechanism from the ionic dominant region to polaronic predominant region has been also observed. Studies revealed the single transition effect at 0.4 mol fraction of V2O5 content.

A phenomenological memristor model for synaptic memory and learning behaviors

Properties that are similar to the memory and learning functions in biological systems have been observed and reported in the experimental studies of memristors fabricated by different materials. These properties include the forgetting effect, the transition from short-term memory（STM） to long-term memory（LTM）, learning-experience behavior, etc. The mathematical model of this kind of memristor would be very important for its theoretical analysis and application design.In our analysis of the existing memristor model with these properties, we find that some behaviors of the model are inconsistent with the reported experimental observations. A phenomenological memristor model is proposed for this kind of memristor. The model design is based on the forgetting effect and STM-to-LTM transition since these behaviors are two typical properties of these memristors. Further analyses of this model show that this model can also be used directly or modified to describe other experimentally observed behaviors. Simulations show that the proposed model can give a better description of the reported memory and learning behaviors of this kind of memristor than the existing model.

Modeling porous structure of oil-pressboard interface and its effect on electric field distribution

The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification and discharge at the interface under certain condition. It is of significant importance to take an insight into the phenomenon occurring at the interface. Through experiment, the pressboard is found as a porous material. The interface changes abruptly from bulk pressboard to the bulk oil as a result of the porous structure. A new model is proposed which divides the interface into bulk oil region, transition region, and bulk pressboard region. The width of the transition region is decided according to the microtome figure. The effective permittivity of the transition region is calculated using a new model based on fractal theory. The model is validated and compared with previous calculation model. The effect of the existence of transition region on the electric field distribution is discussed.

Influence of cooling rate on magneto-structural transition and magnetocaloric effect of Ni_(30)Cu)8Co_(12)Mn_(37)Ga_(13) alloy

The influence of heat treatment with different cooling rates on phase transition behaviors and magnetocaloric effect is systematically studied.Difference in atomic order is induced by changing cooling rates,where ordered phase is obtained in the furnace cooled（FC）sample while disordered phase is reserved in the water quenched（WQ）sample.The coupled magneto-structural transition is detected in both samples but the characteristic temperature significantly shifts to lower temperatures with increasing atomic order.Giant magnetic entropy change（ΔS_（mag））derived from magnetic field induced martensitic transformation is confirmed for both samples,and can be remarkably enhanced by the atomic ordering.The largestΔS_（mag） of 20.9J/（kg·K）is obtained at 307.5Kunder 5Tin the FC sample.

Rapid transition of the hole Rashba effect from strong field dependence to saturation in semiconductor nanowires

With the support by the National Natural Science Foundation of China,a study by the research group led by Prof.Luo Junwei(骆军委)from the Institute of Semiconductors,Chinese Academy of Sciences discovered a rapid transition of the hole Rashba effect from strong field dependence to saturation

Potential shift of bacterial community structure and corrosion-related bacteria in drinking water distribution pipeline driven by water source switching

As a result of pollution in the present water sources,cities have been forced to utilize cleaner water sources.There are few reports regarding the potential shift of bacterial community structure driven by water source switching,especially that of corrosion-related bacteria.Three types of finished water were used for simulation,the polluted source water from the Qiantang and Dongtiaoxi Rivers(China)was replaced by cleaner water from Qiandao Lake(China).Here,we discussed the transition effects through three simulated reactors.The bacterial characteristics were identified using the highthroughput sequencing and heterotrophic plate count method.It was observed that the level of culturable bacteria declined by 2–3 orders of magnitude after water source switching.The bacterial community released from the pipeline reactor was significantly different under different finished water,and it exhibited large variation at the genus level.Porphyrobacter(58.2%)and Phreatobacter(14.5%)clearly replaced Novosphingobium,Aquabacterium,and Cupriavidus as new dominant genera in system A,which could be attributed to the lower carbon and nitrogen content of the new water source.Although corrosion-inhibiting bacteria decreased after switching,they still maintained dominant in three reactors(6.6%,15.9%,and 19.7%).Furthermore,potential opportunistic pathogens such as Sphingomonas were detected.Our study shows that after transition to a high quality water source,the total culturable bacteria released was in a downtrend,which leads to a great reduction in the risk of bacterial leakage in the produced drinking water.