Synthesis and characterization of CuO containing mesoporous silica spheres

A new series of mesoporous silica spheres containing nanodispersed copper oxides were synthesized in H₂O/EtOH/ammonia solution at room temperature. The mesoporous structures were characterised using X-ray powder diffraction and N₂ adsorption-desorption techniques. Scanning electron micrograph and transmission electron micrograph revealed that the MCM-41 particles have spherical morphologies. The DTA curve of pure MCM-41 exhibited a sharp single exothermic peak between 290°C and 340°C, while a broad peak with several shoulders in the temperature range between 180°C and 380°C was observed for Cu-MCM-41, indicating the possible complexation of Cu²⁺ with surfactants adhering to the inner surfaces of the mesopores. Electron paramagnetic resonance spectra of uncalcined samples revealed that Cu²⁺ ions are in an octahedral or distorted octahedral coordination with nitrogen ligands of the surfactant while in the calcined samples they are coordinated with oxygen of the MCM-41 framework. The redox properties of samples were examined by a temperature-programmed reduction and N₂O passivation method. The results indicate that CuO with increasing particle size could be formed in the mesoporous materials with increasing Cu contents, and this decreased the reducibility of the resulting CuO.     

Superposition Representability Problems of Quantum Information Channels

An operator-topological classification method of normal states is given. This result is applied to a study of method of representing normal states on tensor product operator algebras as the superpositions of normal states on subalgebras and quantum information channels. Finally, an entropy theoretic classification method of quantum Markov chains is given.     

Correlation between corrosion rate and AE signal in an acidic environment for mild steel

The AE method is an effective technique for inspecting corrosion damage of mild steel, such as tank bottom floors. However, the correlation between AE signals and corrosion behaviour for mild steel has not yet been fully clarified. In the present study, the authors considered that the corrosion regions of bottom floors become a strong acid environment by Cl⁻, as reported in a previous study. Thus, the polarization resistance for the test pieces of mild steel was measured with an AC impedance method under a strong acid environment. It was clear that the polarization resistance indicated the corrosion rate for a test piece of mild steel in the experiments. While measuring the AE signals, the corrosion rate was monitored with a test piece. As a result, the AE signal showed good correlation with the corrosion rates of the test pieces. The corrosion behaviour of the test pieces was then discussed with the corrosion potential measured during the experiments. Furthermore, the cathode current was changed to control the generated hydrogen gas volume. The volume of the hydrogen gas generated from the cathode reaction was correlated to the AE signals.     

Oversize single-mode H-guide

A new type of H-guide is proposed which is more than ten times as large as the conventional H-guide in transverse dimensions, but can operate in a single mode. A single order of magnitude reduction in attenuation over the single-strip and double-strip H-guide can be achieved with this oversize H-guide     

Lateral growth of GaAs on patterned {-1-1-1}B substrates for the fabrication of nano wires using metalorganic molecular beam epitaxy

We have grown GaAs nano wire structures (45 × 20 nm²) buried in AIAs layers by lateral metalorganic molecular beam epitaxy on the terraced sidewalls of mesa-grooved (-1-1-1)B substrates. The growth of GaAs occurred primarily on the sidewall of the mesa-grooves and not on the (-1-1-1)B surface for arsenic pressures greater than 2.0 × 10⁻³ Pa at a substrate temperature of 480°C. An (0-1-1) facet formation during the lateral epitaxy at the intersection region between the bottom (-1-1-1)B surface and the (1-2-2)A sidewall has been directly observed by real-time scanning microprobe reflection high-energy electron diffraction. The growth rate on the (0111) facet was estimated from the variation of its width with growth time.     

Material balances of organics and nutrients in an oxidation pond

A series of experiments concerning a tertiary oxidation pond was performed from 10 January to 12 November 1979, using a model oxidation pond of 21 m² in capacity. The concentrations of organics and nutrients in influent and pond water were measured so as to consider the conversion of water quality in a tertiary oxidation pond. The sedimentation rates were measured weekly, and the final sediments were analyzed at the end of experiments, so that the material balances in respect to carbon, nitrogen and phosphorus were calculated and the various transition reactions were evaluated quantitatively. The result of the material balances showed that there were three main reactions in pond: the assimilation to algae; the sedimentation of suspended substance; and the decomposition of sediments. The regeneration rates of nutrients from sediments were so active that the removal of nutrients by algal solidification were not effective. Consequently, the overall removal efficiency of nutrients was 45% in total nitrogen and 43% in total phosphorus by a tertiary oxidation pond with 16 days detention time.     

Development of a huge varix following endovascular embolization for cerebellar arteriovenous malformation. A case report

A case is presented of a patient with bilateral retinoblastoma, treated at infancy with surgery, chemotherapy and radiotherapy, who subsequently developed at least four additional histologically distinct malignancies: a Ewing sarcoma of the left fibula, two extraskeletal osteosarcomas of the left lower extremity, a mucoepidermoid carcinoma of the right parotid gland and a squamous cell carcinoma of the left paranasal cavity. In addition to retinoblastoma, patients with a germline RB-1 mutation are at high risk of second primary malignancies. An additive carcinogenic effect of cytotoxic therapy in these patients has been assumed. Patients with hereditary retinoblastoma should be under life-long follow-up programmes including a regular head and neck examination for detection of new primaries, especially in the radiation field of the presenting retinoblastoma.     

Algorithms for Extracting Correct Critical Points and Constructing Topological Graphs from Discrete Geographical Elevation Data

Researchers in the fields of computer graphics and geographical information systems (GISs) have extensively studied the methods of extracting terrain features such as peaks, pits, passes, ridges, and ravines from discrete elevation data. The existing techniques, however, do not guarantee the topological integrity of the extracted features because of their heuristic operations, which results in spurious features. Furthermore, there have been no algorithms for constructing topological graphs such as the surface network and the Reeb graph from the extracted peaks, pits, and passes. This paper presents new algorithms for extracting features and constructing the topological graphs using the features. Our algorithms enable us to extract correct terrain features; i.e., our method extracts the critical points that satisfy the Euler formula, which represents the topological invariant of smooth surfaces. This paper also provides an algorithm that converts the surface network to the Reeb graph for representing contour changes with respect to the height. The discrete elevation data used in this paper is a set of sample points on a terrain surface. Examples are presented to show that the algorithms also appeal to our visual cognition.     

Application of two-dimensional spectral analysis to the evaluation of the single and joint segregation characteristics

Two-dimensional statistical functions such as spectral density function, coherence function and phase angle are used to evaluate the single and joint segregation characteristics of alloying elements. Employing the latter two functions, the joint segregation index, defined elsewhere for a one-dimensional case, is redefined for a two-dimensional one. The effects of calcium treatment on center segregation (macrosegregation) and intergranular segregation (semi-macrosegregation) of MnS in three commercial calcium treated steel slabs, continuously cast under different operating conditions, are quantified by using the joint segregation index. The results are compared with those of a slab without calcium treatment. It is shown that both center segregation and intergranular segregation of MnS in all three calcium treated slabs are suppressed as compared with the slab without calcium treatment, and that the extent of the effect depends on the casting conditions. By reasoning on the basis of two-dimensional power spectra, it is shown that in a calcium treated slab sulfur and calcium are almost uniformly distributed throughout the slab, and that in the slab without calcium treatment sulfur and manganese appear together periodically only at largely spaced positions.