The effect of electrochemical reactions on the surface film composition and corrosion resistance of aluminum in acid solutions

Cathodic polarization was found to reduce the hydrogen transport resistance of the surface oxide film on aluminum, at potentials around -1.65V vs. Ag/AgCl/4M KCl in 0.1M HCl solution. Reduction of film resistance was shown to be due to change of film composition as a consequence of cathodic charging. Formation of surface film was also found at potentials where the film resistance was reduced. The film, which was shown to contain appreciable amounts of water, was found to be an ohmic proton conductor with the conductivity at the same order of magnitude as precipitated aluminum hydroxide;The cathodic product detected by ex-situ infrared spectroscopy is an aluminum oxide or hydroxide which contains water. The peak areas for three major bands increased linearly with cathodic charge suggesting that the film maintains an approximately uniform composition as it become thicker. The spectra for the cathodic products compare most favorably to that of the porous, amorphous oxide films formed by anodizing in acid solution. Aluminum ions in the film are highly coordinated to hydroxyl groups. The OH groups or H[subscript]2O molecules of the film are readily accessible to exchange by D[subscript]2O indicating that the film has an open structure;Cathodic charging of aluminum in acid solution induced an anodic current transient in the passive potential region, accompanied by electrode mass increase, which was primarily due to water absorption into the film. The anodic current decay, by three orders of magnitude, was due to an increase of the film resistance. The reaction with the metal surface of water which had been stored in the film during cathodic charging, to form aluminum oxide, was considered to be responsible for the increase of resistance;The rates of pit initiation and pit growth during the first 30 ms anodic polarization at -0.4V, above the pitting potential, were also enhanced by the prior cathodic charging during the first 30 ms. Pits initiate over a longer period of time with greater oxide film mass. The pitting current diminished if oxidation reaction was allowed to take place more than 20 ms at -0.9V before the potential was stepped to -0.4V. Increase of film resistance by oxidation reaction below the pitting potential was responsible for the decrease of rates of pit initiation and pit growth

Deterministic Dense Coding and Faithful Teleportation with Multipartite Graph States

We proposed novel schemes to perform the deterministic dense coding and faithful teleportation with multipartite graph states. We also find the sufficient and necessary condition of a viable graph state for the proposed scheme. That is, for the associated graph, the reduced adjacency matrix of the Tanner-type subgraph between senders and receivers should be invertible.Comment: 10 pages, 1 figure;v2. discussions improve

A Comparative Study of Thai Adult Learners’ Attitudes Toward Learning Chinese Culture in Chinese as a Foreign Language Class Among Three Levels: Beginner, Intermediate and Advanced at a Chinese Learning Center in Bangkok, Thailand

The aim of this study was to determine Thai adult learners’ attitude toward learning Chinese culture among beginner, intermediate and advanced level, in order to identify whether there was a significant difference among the levels. This study was conducted at a Chinese learning center in Bangkok, Thailand. The study focused on 210 Thai adult learners in a Chinese learning center. They were 100 learners at beginner level, 60 at intermediate level and 50 at advanced level. The researcher used the descriptive statistics and one-way ANOVA to analyze the data. Thai adult learners had positive attitudes toward learning Chinese culture in Chinese as a foreign language class. The result of a one-way analysis of variance showed that there was no significant difference among the three levels: beginner, intermediate and advanced, as the significance was higher than .05 (p > .05). Based on these findings, the researcher gives some suggestions to learners, teachers, school administrators, curriculum developers, and future researchers

Polydipsia-induced hyponatremia and status epilepticus in a schizophrenia patient: A case report from the emergency department

AbstractRelated to severe hyponatremia, various symptoms, such as confusion, vomiting, changes in mental state, status epilepticus, and a variety of conscious disturbances are sometimes seen in the emergency department (ED) but seldom recognized as water intoxication in the early stages. Status epilepticus is an emergent and life-threatening condition if not diagnosed and managed promptly and efficiently. The authors reported a case of a 31-year-old woman with history of schizophrenia with poor drug compliance. The compulsive drinking of more than 15,000mL of water per day for 4 days resulted in intermittent episodes of vomiting and seizures and she was sent to our ED by ambulance. Water intoxication with severe hyponatremia ([Na+]=112mEq/L) was diagnosed and hypertonic sodium supplements and airway protection were then offered. Detailed history taking and early detection of hyponatremia is crucial to prevent fatal complications of water intoxication. Emergency physicians should be suspicious of hyponatremia from water intoxication in psychiatric patients with neurologic symptoms during the observation period in the ED

Multipartite Entanglement Measures and Quantum Criticality from Matrix and Tensor Product States

We compute the multipartite entanglement measures such as the global entanglement of various one- and two-dimensional quantum systems to probe the quantum criticality based on the matrix and tensor product states (MPSs/TPSs). We use infinite time-evolving block decimation (iTEBD) method to find the ground states numerically in the form of MPSs/TPSs, and then evaluate their entanglement measures by the method of tensor renormalization group (TRG). We find these entanglement measures can characterize the quantum phase transitions by their derivative discontinuity right at the critical points in all models considered here. We also comment on the scaling behaviors of the entanglement measures by the ideas of quantum state renormalization group transformations.Comment: 22 pages, 11 figure

Symmetry Protected Quantum State Renormalization

Symmetry protected topological (SPT) phases with gapless edge excitations have been shown to exist in principle in strongly interacting bosonic/fermionic systems and it is highly desirable to find practical systems to realize such phases through numerical calculation. A central question to be addressed is how to determine the SPT order in the system given the numerical simulation result while no local order parameter can be measured to distinguish the phases from a trivial one. In the tensor network approach to simulate strongly interacting systems, the quantum state renormalization algorithm has been demonstrated to be effective in identifying the intrinsic topological orders. Here we show that a modified algorithm can identify SPT orders by extracting the fixed point entanglement pattern in the ground state wave function which is essential for the existence of SPT order. The key to this approach is to add symmetry protection to the quantum state renormalization process and we demonstrate the effectiveness of this algorithm with the example of AKLT states in both 1D and 2D