Formation of niobium oxide nanowires by thermal oxidation

In this report, we describe simple thermal oxidation of niobium for the fabrication of niobium oxides, emphasizing that niobium oxide nanowires can be prepared upon the concentration of oxygen in the environment. For example, dense Nb₂O₅ nanowires on thin oxide film are produced if the annealing is performed in a restricted concentration of oxygen (herein, 3 Torr vacuum). If most of the oxygen is removed in the environment, the nanowires are sparely formed. The nanowires consist of a superlattice monoclinic Nb₂O₅ with a growth direction of [0 0 1].     

Thermal fatigue estimation due to thermal stratification in the RCS branch line using one-way FSI scheme

The scheme and procedure for thermal fatigue estimation of a thermally stratified branch line were developed. One-way FSI (fluid and structure interaction) scheme was applied to evaluate the thermal stratification piping. Thermal flow analysis, stress analysis and fatigue estimation were performed in serial order. Finally, detailed monitoring locations and mitigation scheme for the integrity maintenance of piping were recommended. All wall mesh and transient temperature distribution data obtained from the CFD (computational fluid dynamics) analysis were directly imported into the input data of stress analysis model without any calculation for heat transfer coefficients. Cumulated usage factors for fatigue effect review with nodes were calculated. A modified method that combines ASME Section III, NB-3600 with NB-3200 was used because the previous method cannot consider the thermal stratification stress intensity. As the results of evaluation, the SCS (shutdown cooling system) line, branch piping of the RCS (reactor coolant system) line, shows that the CUF (cumulative usage factor) value exceeds 1.0, ASME Code limit, in case thermal stratification load is included. The HPSI (high pressure safety injection) line, re-branch piping, shows that temperature difference between top and bottom of piping exceeds the criterion temperature, 28°C, and that the CUF value exceeds 1.0. Therefore, these branch pipings require a detailed review, monitoring or analysis. In particular, it is recommended that the HPSI piping should be shifted backward to decrease the influence of turbulent penetration intensity from the RCS piping. This paper was recommended for publication in revised form by Associate Editor Jae Young Lee Kwang-Chu Kim received his B.S., M.S. and Ph.D degrees from department of mechanical engineering, Kyunghee University in 1993, 1995 and 2000, respectively. He has worked for Korea Power Engineering Company since 1995 and he is now a senior researcher. Dr. Kim’s research area includes CFD analysis, flow control, plant design and simulator. Jong-Han Lim received his B.S. degree from department of mechanical engineering, Chosun University in 1981, M.S. and Ph.D degrees from department of mechanical engineering, Kyunghee University in 1986 and 1992, respectively. He worked for Hyundai Motors Company during 1986-95. He is now a professor in department of mechanical & automotive engineering, Kyungwon University. Dr. Lim’s research interests are in the area of thermal flow, internal combustion and liquid atomization. Jun-Kyu Yoon received his B.S. degree from department of mechanical engineering, Chosun University in 1981, M.S. degree from department of mechanical engineering, Kyunghee University in 1987 and Ph.D degree from department of mechanical engineering, Myongji University in 2001. He worked for Hyundai Motors Company and Asia Motors Company during 1985–96. He is now a professor in department of mechanical & automotive engineering, Kyungwon University. Dr. Yoon’s research interests are in the area of flow control, heat transfer, liquid atomization, spray and combustion.     

Calculation of input-voltage standing-wave ratio for a reflector antenna

A simple method is presented for the calculation of the energy reabsorbed by the feed in an antenna system. The method is applied to determine the v.s.w.r. when a dielectric-cone feed is used to illuminate a subreflector.     

Standing-gradient osmotic flow. Examination of its validity using an analytical method

The development of pathological lesions in the organs of rabbits was examined at intervals from 1 h to 4 days after aerosol infection with Francisella tularensis. The earliest change, accumulation of polymorphonuclear leucocytes (PMN) in ulmonary alveolar ducts, occurred at 19 h. From the 2nd day multiple foci of necrosis and PMN infiltration were present in large airways and alveoli throughout the lungs and progressively increased in size. Pulmonary arteritis was a prominent feature of the infection. Areas of necrosis were present in the nasal mucosa, pharynz and trachea, and pyogranolomatous lesions consistently developed in the liver, spleen, and lymph nodes.     

On the calculation of resistance of the multiple driven rod electrode

Expressions for the resistance of symmetrical multiple driven rod electrodes are derived using both the conceptually correct equal potential condition and the approximate equal charge or average potential method. Computed results for several such electrode systems of practical dimensions are presented, allowing a comparison of the two methods. A general expression for the resistance of a non-symmetrical bed of driven electrodes is also derived.     

The scanning Kelvin probe; a new technique for the in situ analysis of the delamination of organic coatings

Corrosion reactions which take place during delamination in the vicinity of defects have not been understood up to now. In this paper the delamination of a simple model coating from clean steel and the delamination of technical coatings from petreated steel substrates are analysed with a scanning Kelvin probe. It is possible, with this technique, to follow the delamination in situ and to understand the basic corrosion mechanism at the metal/polymer interface.     

Accurate design of a corner fed square slot patch antenna forcircular polarisation

New fast form analytic expressions to determine the impedance elements of the desegmentation matrix have been obtained. These results, using the Green's function approach, enable an accurate determination of the dimensions of the slot at the centre of a corner fed square patch antenna to produce circular polarisation     

PAK promotes morphological changes by acting upstream of Rac

The serine/threonine kinase p21-activated kinase (PAK) has been implicated as a downstream effector of the small GTPases Rac and Cdc42. While these GTPases evidently induce a variety of morphological changes, the role(s) of PAK remains elusive. Here we report that overexpression of betaPAK in PC12 cells induces a Rac phenotype, including cell spreading/membrane ruffling, and increased lamellipodia formation at growth cones and shafts of nerve growth factor-induced neurites. These effects are still observed in cells expressing kinase-negative or Rac/Cdc42 binding-deficient PAK mutants, indicating that kinase- and p21-binding domains are not involved. Furthermore, lamellipodia formation in all cell lines, including those expressing Rac binding-deficient PAK, is inhibited significantly by dominant-negative RacN17. Equal inhibition is achieved by blocking PAK interaction with the guanine nucleotide exchange factor PIX using a specific N-terminal PAK fragment. We conclude that PAK, via its N-terminal non-catalytic domain, acts upstream of Rac mediating lamellipodia formation through interaction with PIX.     

Analysing the natural resting aspect of a component for automated assembly using the energy envelope method

This paper presents a new approach for analysing the natural resting behaviour of a non-rotational component. The method employs the energy envelope concept to analyse the natural resting of a component. The resultant curves for all the prisms agree well with Boothroyd's theoretical curve and Boothroyd's experimental data.