SnO-SnO2 modified two-dimensional MXene Ti3C2Tx for acetone gas sensor working at room temperature

Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO2 (p-n junction) and Ti3C2Tx MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO2,forming in-situ p-n junctions on the surface of SnO.The hamburger-like SnO-SnO2/Ti3C2Tx sensor exhibited improved acetone gas sensing response of 12.1 (Rg/Ra) at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti3C2Tx and pristine SnO-SnO2,respectively.Moreover,it expressed a short recovery time (9 s) and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti3C2Tx nanosheets,acting as a hole accumulation layer (HALs) between Ti3C2Tx and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti3C2Tx MXene in SnO-SnO2/Ti3C2Tx sensors was discussed in detail.     

Manufacture of three-layer wood–porcelain stone composite board reinforced with bamboo fiber

The objective of this study was to improve bending strength properties of three-layer wood–porcelain stone composite board. The focus of this study was on the effects of orientations and weight ratios of bamboo fiber in face layer on physical and mechanical properties of the board. Three types of board with different orientation of bamboo fibers in the face layer were manufactured: one in which the fibers were oriented at random orientation (R board), another in which the fibers were oriented at unidirectional orientation (U board), and a third in which the fibers were oriented at cross orientation (C board). The physical and mechanical properties of the boards were evaluated based on the Japanese Industrial Standard for Particleboards. The main results obtained were as follows: Bending strength properties of the board were strongly affected by both orientation and weight ratio of bamboo fibers. Perpendicular specimen of C board has larger bending strength properties than U board and the value become larger with increased weight ratio of bamboo fibers. Internal bond strength value decreased with increasing weight ratio of bamboo fibers. The effect of orientation and weight ratios of bamboo fiber on thickness swelling of the board was not significant.     

The structure of crystalline polyethylene sulphide — a laser Raman study

That polyethylene sulphide crystallizes in lamellar units within spherulites, has been presumed. In this paper further evidence for lamellae from Raman spectroscopy is presented and discussed. Thickening of the lamellae betweenT _M-90 andT _M-15 is also demonstrated.     

Structure and properties of linear polyethylene crystallized by rapid cooling of melts: 3. The effect of shear

This paper investigates the relationship between the mechanical performance of an injection moulded product and the flow and temperature characteristics within the mould during manufacture. This has been achieved by devising a laboratory experiment involving production of a thin moulded rod. We have shown that the modulus in linear polyethylene is anomalously high when the polymer melt is rapidly solidified whilst being exposed to a high shear gradient. We have related this observation to the morphology of the solid product.     

WebFindIt: an architecture and system for querying Web databases

The Web offers a single user interface to data sharing across heterogeneous and autonomous databases, but it was not designed to handle the rigid DBMS protocols and data formats used by relational and object-oriented databases. WebFindIt is an ongoing project to develop the database equivalent of the World Wide Web-namely, a World Wide Database-through a middleware infrastructure for describing, locating, and accessing data from any kind of Web-accessible database. A special-purpose language, Web-Tassili, supports the definition and manipulation of middleware constructs for organizing the information space. An implementation of WebFindIt combines Java, CORBA and database technologies     

Application of Reproducing Kernel Hilbert Spaces to a Minimization Problem with Prescribed Nodes

The theory of reproducing kernel Hilbert spaces is applied to a minimization problem with prescribed nodes. We re-prove and generalize some results previously obtained by Gunawan et al. [2,3], and also discuss the Hölder continuity of the solution to the problem.     

Polydopamine as an intermediate layer for silver and hydroxyapatite immobilisation on metallic biomaterials surface

Hydroxyapatite (HA) coated implant is more susceptible to bacterial infection as the micro-structure surface which is beneficial for osseointegration, could also become a reservoir for bacterial colonisation. The aim of this study was to introduce the antibacterial effect of silver (Ag) to the biomineralised HA by utilising a polydopamine film as an intermediate layer for Ag and HA immobilisation. Sufficient catechol groups in polydopamine were required to bind chemically stainless steel 316 L, Ag and HA elements. Different amounts of Ag nanoparticles were metallised on the polydopamine grafted stainless steel by varying the immersion time in silver nitrate solution from 12 to 24 h. Another polydopamine layer was then formed on the metallised film, followed by surface biomineralisation in 1.5 Simulated Body Fluid (SBF) solution for 3 days. Several characterisation techniques including X-Ray Photoelectron Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Contact Angle showed that Ag nanoparticles and HA agglomerations were successfully immobilised on the polydopamine film through an element reduction process. The Ag metallisation at 24 h has killed the viable bacteria with 97.88% of bactericidal ratio. The Ag was ionised up to 7 days which is crucial to prevent bacterial infection during the first stage of implant restoration. The aged functionalised films were considered stable due to less alteration of its chemical composition, surface roughness and wettability properties. The ability of the functionalised film to coat complex and micro scale metal make it suitable for dental and orthopaedic implants application.     

Development of 2-axis hybrid positioning system for precision contouring on micro-milling operation

A 2-axis hybrid positioning system was developed for precision contouring on micro-milling operation. The system was developed to overcome the micro-positioning limitations of conventional linear stage positioning system on machine tools. A 2-axis flexure hinge type piezoelectric stage was added on a standard milling machine to obtain better machining results. The control method used for the hybrid system was active error compensation type, where errors from linear stages are cancelled by the piezoelectric stage motion. Positioning experiments showed an improvement of machine accuracy which was confirmed by the machining results. A micro-pillar was fabricated for the validation of long-range and high-precision contouring capability. The system was successfully implemented on micro-milling machining to achieve high-precision machining results.