Representation of scanning probe images in virtual reality

The visualization of the data obtained with scanning probe microscopes can be improved by the use of virtual reality software which has recently become available commercially. One such software program was applied to images obtained with an atomic force microscope. The mapping capabilities of this new visualization technique as well as the images were quite striking when viewed in virtual reality.     

The tetrahedral tip as a probe for scanning near-field optical microscopy at 30 nm resolution

The tetrahedral tip is introduced as a new type of a probe for scanning near-field optical microscopy (SNOM). Probe fabrication, its integration into a scheme of an inverted photon scanning tunnelling microscope and imaging at 30 nm resolution are shown. A purely optical signal is used for feedback control of the distance of the scanning tip to the sample, thus avoiding a convolution of the SNOM image with other simultaneous imaging modes such as force microscopy. The advantages of this probe seem to be a very high efficiency and its potential for SNOM at high lateral resolution below 30 nm.     

Changes in microstructure,phases, and hydrogen storage characteristics of metal hydro-borate and nickel-added magnesium hydride with hydrogen absorption and release reactions

In this work, Zn(BH₄)₂ and/or Ni were added to MgH₂ in order to improve the hydrogen absorption and release properties of MgH₂. 99 wt% MgH₂ + 1 wt% Zn(BH₄)₂, 99 wt% MgH₂ + 0.5 wt% Zn(BH₄)₂ + 0.5 wt% Ni, and 95 wt% MgH₂ + 2.5 wt% Zn(BH₄)₂ + 2.5 wt% Ni samples [named MgH₂-1Zn(BH₄)₂, MgH₂-0.5Zn(BH₄)₂-0.5Ni, and MgH₂-2.5Zn(BH₄)₂-2.5Ni, respectively] were prepared by milling in a planetary ball mill in a hydrogen atmosphere. MgH₂-0.5Zn(BH₄)₂-0.5Ni had the highest initial hydriding and dehydriding rates and the largest quantities of hydrogen absorbed and released for 20 min. MgH₂-0.5Zn(BH₄)₂-0.5Ni dehydrided at the fourth cycle had small particles, large particles, and agglomerates. The sizes of the fine particles on the agglomerates were slightly smaller than those in the as-milled sample and quite flat surfaces of the agglomerates were not observed. MgH₂-0.5Ni-0.5Zn(BH₄)₂ dehydrided at 623 K under 1.0 bar H₂ at the 4th cycle contained Mg, MgO, and small amounts of β-MgH₂ and Mg₂Ni. The initial hydriding rates at n = 2, 3, and 4 were higher than that at n = 1. The quantity of hydrogen absorbed for 60 min, H_a (60 min), decreased as the number of cycles, n, increased. The initial dehydriding rate increased and the quantity of hydrogen released for 60 min, H_r (60 min), decreased as n increased. Outside the particles and agglomerates, particles became finer due to expansion and contraction, while in their interiors cracks were believed to coalesce due to annealing effect. MgH₂-0.5Ni-0.5Zn(BH₄)₂ had an effective hydrogen storage capacity (the quantity of hydrogen absorbed for 60 min) of about 5.5 wt% (5.52 ± 0.10 wt% at 593 K under 12 bar H₂). The PCT curve of MgH₂-0.5Ni-0.5Zn(BH₄)₂ showed that the hydrogen storage capacity was 6.64 ± 0.25 wt%.     

Determination of ochratoxin A in wines by capillary liquid chromatography with laser induced fluorescence detection using dispersive liquid-liquid microextraction

A method based on reverse phase capillary high performance liquid chromatography (capillary HPLC) coupled to laser-induced fluorescence detection (LIF) has been proposed for the determination of ochratoxin A (OTA) in wine samples. An anionic micellar medium was added to the mobile phase for increasing the fluorescence intensity and peak efficiency. Dispersive liquid-liquid microextraction (DLLME) has been used as a simple and efficient sample pretreatment method for the analysis of OTA in wines, being optimised by means of experimental design. The limit of detection was 5.5 ng L(-1) (3 × S/N) and recoveries for different wines ranged from 91.7 to 98.1%. The proposed methodology could be classified as a green analytical chemistry alternative, combining the low organic solvent volumes required in the DLLME with the reduced consumption of mobile phase in capillary HPLC. The use of LIF as detector provided an extremely sensitive method for the determination of OTA in wines.     

Efficient H2 production by photocatalytic water splitting under UV or solar light over variously modified TiO2-based catalysts

This paper focused for the first time on the comparison between three different approach to modify the chemico-physical properties of TiO₂-based photocatalysts and their effect in the H₂ production by photocatalytic water splitting both under UV and solar light irradiation, under the same experimental conditions. The application of pulsed laser irradiation to aqueous TiO₂ suspensions (first approach) induced structural transformations both on the bulk and on the surface of TiO₂, boosting the H₂ production, under UV light irradiation, of almost three times (20.9 mmol/g_cat·h) compared to bare TiO₂ (7.7 mmol/g_cat·h). The second strategy was based on a templating method to obtain TiO₂ with a macroporous structure to favour an efficient light absorption process inside the material pores, thus allowing a high H₂ production (0.64 mmol/g_cat·h) under solar light irradiation. This performance was further enhanced when the macroporous TiO₂ was coupled with CeO₂ or W (third approach). In the latter case the H₂ production increased to 0.72 mmol/g_cat·h for macroporous TiO₂CeO₂ and to 0.82 mmol/g_cat·h for macroporous TiO₂W. This work highlights how it is possible to tune the TiO₂ photocatalytic properties with easy and green procedures to obtain environmental friendly catalyst for hydrogen production.     

Effect of polyphenolic ingredients on physical characteristics of cheese

A novel cheese product developed based on the incorporation of various polyphenolic compounds was evaluated for its texture characteristics. Single phenolic compounds including catechin, epigallocatechin gallate (EGCG), tannic acid, homovanillic acid, hesperetin and flavone, along with natural crude compounds such as grape extract, green tea extract and dehydrated cranberry powder, were added as functional ingredients during the cheese-making process. Cheese curds containing polyphenolic compounds at a concentration of 0.5 mg/mL showed a decrease of curd moisture content (CMC) while the gel strength (GS) was not affected. Structural differences were observed when crude polyphenolic compounds were added to the cheese, resulting in rough and granular structures. Physical properties of the cheese product were evaluated after adding bioactive phenolic compounds to the cheese curd. We fully expect to apply this approach to other dairy products in the future.     

两相圆湍射流中Stokes数的影响

以Ｒｅ＝ ５ ６４０ 的水平圆湍射流为对象,用粒子动态分析仪详细测量了单相及两相射流近场（ｘ／Ｄ＜ １５）的轴向和径向时均速度、湍动能及颗粒相浓度的分布。实验选用粒径分布分别为２５±３μｍ 、７０±５ μｍ 和１００±１０ μｍ 等的玻璃微珠（密度ρｐ＝ ２ ５９０ ｋｇ／ｍ ３）代表颗粒相,分析了两相圆湍射流中Ｓｔｏｋｅｓ数变化对射流特性的影响。实验结果表明,Ｓｔ＜ １ 时应考虑颗粒相与气相湍流拟序结构的相互影响,在射流近场的横向截面上,颗粒相轴向速度有超前气相的现象。随着Ｓｔｏｋｅｓ数的增大,颗粒相速度低于气相速度。由于颗粒相的加入,与单相射流相比,两相湍射流中的气相湍动能发生变化。当Ｓｔ＜ １ 和Ｓｔ１ 时,气相湍能都呈增大的趋势,但二者增大的原因不同。     

Thermal characterisation of ceramic/metal joining techniques for fusion applications using X-ray tomography

This work investigates the thermal performance of four novel CFC–Cu joining techniques. Two involve direct casting and brazing of Cu onto a chromium modified CFC surface, the other two pre-coat a brazing alloy with chromium using galvanisation and sputtering processes. The chromium carbide layer at the interface has been shown to improve adhesion. Thermal conductivity across the join interface was measured by laser flash analysis. X-ray tomography was performed to investigate micro-structures that might influence the thermal behaviour. It was found that thermal conductivity varied by up to 72%. Quantification of the X-ray tomography data showed that the dominant feature in reducing thermal conductivity was the lateral spread of voids at the interface. Correlations were made to estimate the extent of this effect.     

Nanostructured MIEC Ba0.5Sr0.5Co0.6Fe0.4O3−δ (BSCF5564) cathode for IT-SOFC by nitric acid aided EDTA–citric acid complexing process (NECC)

Ba_0.5Sr_0.5Co_0.6Fe_0.4O_3−δ(BSCF5564) was synthesized by nitric acid aided EDTA–citric acid complexing sol-gel method (NECC). Both, the phase formation temperature and time of BSCF5564 synthesized NECC were found to be low i.e. single perovskite phase formation temperature is 200 °C less as compared to the conventional method of synthesis. The orthorhombic perovskite structure has been formed after calcination at 800 °C for 5 h. Scanning electron microscopy reveals the formation of porous material constituting nano-sized and irregularly shaped rod-like structure with particle size approximately ranges from 90 to 160 nm. The total weight loss of the BSCF5564 sample comes out to be 6.6%, indicating that quadrivalence state Co⁴⁺ and Fe⁴⁺ in the sample have been completely reduced to the trivalent state Co³⁺ and Fe³⁺ due to thermal analysis. The value of E_a for BSCF5564 prepared by NECC was 0.2288 eV. The electrical conductivity of BSCF5564 synthesized by NECC is observed to be steady at high temperature (above 700 °C).     

Laser-printed thick-film electrodes for solid-state rechargeable Li-ion microbatteries

Laser-printed thick-film electrodes (LiCoO₂ cathode and carbon anode) are deposited onto metallic current collectors for fabricating Li-ion microbatteries. These microbatteries demonstrate a significantly higher discharge capacity, power and energy densities than those made by sputter-deposited thin-film techniques. This increased performance is attributed to the porous structure of the laser-printed electrodes, which allows improved ionic and electronic transport through the thick electrodes (∼100 μm) without a significant increase in internal resistance. These laser-printed electrodes are separated by a laser-cut porous membrane impregnated with a gel polymer electrolyte (GPE) in order to build mm-size scale solid-state rechargeable Li-ion microbatteries (LiCoO₂/GPE/carbon). The resulting packaged microbatteries exhibit a power density of ∼38 mW cm⁻² with a discharge capacity of ∼102 μAh cm⁻² at a high discharge rate of 10 mA cm⁻². The laser-printed microbatteries also exhibit discharge capacities in excess of 2500 μAh cm⁻² at a current density of 100 μA cm⁻². This is over an order of magnitude higher than that observed for sputter-deposited thin-film microbatteries (∼160 μAh cm⁻²).