In situ formation of BN nanotubes during nitriding reactions

High-yield multiwalled boron nitride (BN) nanotubes have been produced using a ball milling-annealing method. The BN nanotubes with a diameter less than 10 nm and a well-crystallized multiwalled structure were formed via an in situ nitriding reaction. The systematic investigation of the formation process at different annealing temperatures and for different times suggested that the formation of the unique multiwalled structure was attributed by a two-dimensional growth of the BN phase and a nonmetal catalytic growth.

An electrochemical impedance study of ionic liquid film formation and aqueous corrosion of magnesium alloy ZE41

Ionic liquid surface treatments are proposed as a method of controlling corrosion processes on magnesium alloys. An important magnesium alloy, ZE41 (nominally 4% Zn and 1% rare earth), was treated with the ionic liquid trihexyl(tetradecyl)phosphonium diphenylphosphate (P₆₆₆₁₄DPP). Impedance spectra were acquired at intervals during the treatment, indicating the development of a film and allowing a measure of the film formation process to be obtained over time. Mechanically polished and electro-polished surfaces were prepared; these surfaces, treated and untreated, were subsequently exposed to 0.1 M NaCl aqueous solutions. The corrosion behavior of the prepared surfaces were assessed using impedance spectroscopy and optical microscopy. The results indicated a significant role for the method of surface preparation used and, in both cases, the ionic liquid treatment produced a more corrosion-resistant surface.

Real-time, in-situ, extinction spectroscopy studies on silver-nanoseed formation

In this paper, real-time extinction spectroscopy was employed to analyze in situ the fast formation process of silver seeds. The influencing factors for silver-seed formation, including the concentration of the reducer (NaBH 4), the amount of stabilizer (citrate), and the addition procedure of NaBH4, were evaluated. The configuration of the surface plasmon resonance (SPR) spectra of silver nanoparticles, which reflected the morphology of the produced silver seeds, was found to be distinctly affected by the NaBH4 concentration. Homogeneous silver nanoparticles were obtained when the added NaBH4 was lower in concentration than 2.00 mM. In contrast, higher concentrations of reducing agent (>3.00 mM NaBH4) resulted in uneven silver nanoparticles. Mie theory was applied to clarify the correlation of the SPR and the size of the silver seeds. Repeated additions of a small amount of the reducing agent could increase the monodispersity and isotropy of silver seeds. Real-time extinction spectroscopy is a convenient technique that achieves the in-situ and nondestructive measurement of intermediates in the formation process of silver nanoseeds.

Formation of nanoscale titanium carbides in ferrite: an atomic study

The formation and evolution of nanoscale titanium carbide in ferrite during the early isothermal annealing process were investigated via molecular dynamics simulation. The atomic interactions of titanium and carbon atoms during the initial formation process explained the atoms aggregation and carbides formation. It was found that the aggregation and dissociation of titanium carbide occurred simultaneously, and the composition of carbide clusters varied in a wide range. A mechanism for the formation of titanium carbide clusters in ferrite was disclosed.

Economic transition and commercial property markets : China and Poland

This paper discusses the economic transition and the property market emergence in transition economies. It compares the Chinese property market with the Polish market. It preliminarily examines market emergence and maturity in the context of economic transition, comparing the transitions with the emphasis placed on commercial property markets especially their formation and behaviour. Supply and demand for commercial space in China and Poland are also contrasted. As commercial property market behaviour is somewhat driven by market structure formation process and the business cycle, the transition has provided a “common ground” that enables similarities between the property markets in China and Poland. The challenge for state intervention is mainly due to the agency problem which is also a problem in mature markets; it appears that transitional economies do share common features in their emerging property markets. This paper suggests state intervention in market formation and emergence is necessary and essential. However the actual formation and behaviour of property markets have some distinctive characteristics. Value or implication of the study include: knowing the stage of market emergence is essential for making investment decisions, especially when identifying markets with varying backgrounds. This paper is also relevant to policy-makers in the process of facilitating transitions in emerging markets.

The 1990's property cycle in Hainan

The continuous debate between the radical and the conservative approaches on which one is more suitable for a successful economic transition seems to be in favour of the latter. With the recent upswing in the property market in Hainan, the review of the 1990s property cycle in Hainan is linked with economic transition in China. A case study approach is used to establish the importance of the 1990s Hainan property cycle to the formation process of the Chinese property market system. The analytical framework is an integration of the theories of property cycles and economic transition, using the conceptual model of typical commercial property markets modified according to the historical settings in Hainan. It is found that the 1990s Hainan property cycle is unique in that the economic transition has been the key driving force. The structural imbalance caused by the equally imbalanced reform process in different sectors in Hainan has been proved an unsuccessful practice. By and large, the 1990s cycle in Hainan lasted for about 10 years and was state-driven. It was considered an experiment conducted by the state in testing the radical approach of economic transition in the property and urban land sectors. It is suggested that current knowledge of emerging commercial property markets, especially their cyclical behaviour, is limited at both theoretical and empirical levels. Evidence from the past 15 years seems to suggest that the structural and investment imbalance in the economic transition was the main cause of the high volatility in the Hainan property market in the 1990s. The emergence of a commercial property market seems to require choosing the right places to start reform with great caution on investment structure and the fundame ntals of the real economy. Eventually, it is essential to adopt a systematic view to assess and to make decision in the process of emergence of property cycles, based on the basic demand and supply patterns in a city’s transitional economy.

The interactional effects of the internal and external university environment, and the influence of personal values, on satisfaction among international postgraduate students

The article investigates the interactional effects of internal and external university learning environments, and the influence of personal values, in the satisfaction formation process of international postgraduate students from Asia. Past research on student satisfaction has been narrowly focused on certain aspects of the university internal environment such as teaching, learning and support services. While acknowledging the impact of the internal learning environment on student satisfaction, the article argues that the external community environment, where students spend most of their academic life, has a much stronger influence on their satisfaction. It is also argued that students’ personal values have a mediating influence on the impact on student satisfaction of the internal and external learning environments. A sample of 411 international postgraduate business students from five Australian universities is used in the study. Structural equation modelling is used to analyse the data. Practical implications for universities are provided.

Stereo vision and wavelets/multiwavelets analysis : 3d reconstruction using wavelets/multiwavelets theory and stereo vision

During the image formation process of the camera, explicit 3D information about the scene or objects in the scene are lost. Therefore, 3D structure or depth information has to be inferred implicitly from the 2D intensity images. This problem is com- monly referred to as 3D reconstruction. In this work a complete 3D reconstruction algorithm is presented, capable of reconstructing dimensionally accurate 3D models of the objects, based on stereo vision and multi-resolution analysis. The developed system uses a reference depth model of the objects under observation to improve the disparity maps, estimated. Only a few features are extracted from that reference model, which are the relative location of the discontinuities and the z-dimensional extremes of objects depth. The maximum error deviation of the estimated depth along the surfaces is less than 0.5mm and along the discontinuities is less than 1.5mm. The developed system is invariant to illuminative variations, and orientation, location and scaling of the objects under consideration, which makes the developed system highly robust.

Model-based character recognition in low resolution

We propose a combined character separation and recognition approach for low-resolution images of alphanumeric text. By synthesising the image formation process a set of low-resolution templates is created for each character. Cluster algorithms and normalised cross-correlation are then applied to match these templates and thereby allowing both character separation and recognition to be achieved at the same time. Thus characters are recognised using their low-resolution appearance only without applying image enhancement methods. Experiments showed that this approach is able to recognise low-resolution alphanumeric text of down to 5 pixels in size.

V2O5·nH2O crystalline nanosheets : hydrothermal fabrication and structure evolution

V2O5·nH2O nanosheets are fabricated hydrothermally with the acidified peroxovanadate solution at 200 °C for 12 h. The X-ray diffraction suggests that V2O5·nH2O nanosheets display lamellar ordering along c-axis direction. Transmission electron microscopy, field-emission scanning electron microscopy, and selected area electron diffraction indicate that V2O5·nH2O nanosheets are very thin in thickness and micron-sized in lateral dimension, and they are two-dimensional crystallites. X-ray photoelectron spectroscopy and thermogravimetric analysis are utilized to confirm the elemental composition of nanosheets. The formation process of nanosheets is also discussed in terms of time- and temperature-controlled experiments.

Comparative study on MoO3 and HxMoO3 nanobelts : structure and electric transport

In this study, the suspension of MoO3 nanobelts was first prepared in a hydrothermal way from Mo powders and H2O2 solution, which could be transformed into the suspension of HxMoO3 nanobelts under an acidic condition using N2H4 ·H2O as the reducing agent. Three paper-form samples made from MoO3 and HxMoO3 nanobelts (low or high hydrogen content) were then fabricated via a vacuum filtration method, followed by their structural comparative analysis such as FESEM, XRD, Raman spectra, and XPS, etc. The measurement of electric resistances at room temperature shows that the conductance of HxMoO3 nanobelts is greatly improved because of hydrogen doping. The temperature-dependent resistances of HxMoO3 nanobelts agree with the exponential correlation, supporting that the conducting carriers are the quasi-free electrons released from Mo5+. In addition, the formation process of HxMoO3 nanobelts from MoO3 nanobelts is also discussed.

Facile synthesis of silver submicrospheres and their applications

Uniform silver submicrospheres were synthesized under ambient conditions, through reduction of silver nitrate using ascorbic acid as a reducing agent and Tween 20 as a stabilizer. The silver submicroparticles exhibited strong catalytic activity for the reduction of 4-nitrophenol by sodium borohydride (NaBH4). Significantly, the aggregates of a few silver submicroparticles can be used as surface-enhanced Raman scattering (SERS) substrate to improve markedly the Raman signal of crystal violet. The morphologies of silver submicroparticles can be controlled by changing reaction conditions. The formation process of silver submicroparticles was monitored by time-resolved extinction spectroscopy. The influences of concentrations and molar ratios of reaction reagents on the formation of silver submicroparticles are discussed.

Current trends in machinability research

The manufacturing index of a country relies on the quality of manufacturing research outputs. Theemergence of new materials such as composites and multi component alloy has replaced traditionalmaterials in certain design application. Materials with properties like high strength to weight ratio,fatigue strength, wear resistance, thermal stability and damping capacity are a popular choice for adesign engineer. Contrary, the manufacturing engineer is novice to the science of machining thesematerials. This paper is an attempt to focus on the current trends in machinability research and anaddition to the existing information on machining. The paper consist of information on machiningAustempered Ductile Iron (ADI), Duplex Stainless Steel and Nano-Structured Bainitic Steel. Thevarious techniques used to judge the machinability of these materials is described in this paper.Studying the chip formation process in duplex steel using a quick stop device, metallographic analysisusing heat tinting of ADI and cutting force analysis of Nano-structured bainitic steel is discussed.

Modulated deformation of lipid membrane to vesicles and tubes due to reduction of graphene oxide substrate under laser irradiation

Biomembrane transformations are closely related to many biological processes including endo/exocytosis and the cellular response to the local physical environment. In this work, we investigated the transformation between lipid membranes and lipid vesicles/tubes modulated by the solid substrate of graphene oxide (GO) aggregates under laser irradiation. We firstly fabricate a novel type of lipid@GO composite consisting of micrometer-sized GO aggregates surrounded by lamellar lipid membranes. Upon laser irradiation, lipid protrusion occurs and leads to the formation of vesicles adsorbed on the GO aggregate surface, with an average size as 0.43 times of the radius of GO aggregate. Both the location and the dynamic formation process of vesicles can be modulated. The arising of vesicles prefers to occur at edges of the GO planes rather than on surface of individual GO sheets within the GO aggregate. Furthermore, at a reduced laser power density, the lipid protrusion mainly grows to tubes instead of vesicles. Such transformations from lipid membrane to vesicles and tubes is ascribed to the reduction of GO to reduced-GO (rGO) under laser irradiation, probably along with the release of gases leading to the deformation of lipid membrane surrounding the GO surface.