Analysis of chromosomal DNA patterns of the genus Kluyveromyces

Using an improved procedure of pulsed field gel electrophoresis, yeast chromosomes were separated over a wide range of molecular size (250-4000 kbp) on single gels. The chromosomal DNA patterns of all the species belonging to the genus Kluyveromyces were examined. Within the species K. marxianus, the varieties lactis, drosophilarum and vanudenii showed closely related patterns: very different from them, the varieties bulgaricus and marxianus were related to each other, forming a distinct group; the strains commonly called 'K. lactis' and 'K. fragilis' were unambiguously different from each other in chromosome patterns. These differences were correlated with the presence of characteristic repetitive sequence elements in the mitochondrial DNA of the former group and not in the latter. Analysis of Candida macedoniensis, which had been considered to be an anamorph of K. marxianus var. marxianus, showed that these two yeast species were indeed similar in chromosome patterns and in mitochondrial DNA restriction patterns.     

Lead‐Free Polycrystalline Ferroelectric Nanowires with Enhanced Curie Temperature

Ferroelectrics are important technological materials with wide‐ranging applications in electronics, communication, health, and energy. While lead‐based ferroelectrics have remained the predominant mainstay of industry for decades, environmentally friendly lead‐free alternatives are limited due to relatively low Curie temperatures (T _C) and/or high cost in many cases. Efforts have been made to enhance T _C through strain engineering, often involving energy‐intensive and expensive fabrication of thin epitaxial films on lattice‐mismatched substrates. Here, a relatively simple and scalable sol–gel synthesis route to fabricate polycrystalline (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ nanowires within porous templates is presented, with an observed enhancement of T _C up to ≈300 °C as compared to ≈90 °C in the bulk. By combining experiments and theoretical calculations, this effect is attributed to the volume reduction in the template‐grown nanowires that modifies the balance between different structural instabilities. The results offer a cost‐effective solution‐based approach for strain‐tuning in a promising lead‐free ferroelectric system, thus widening their current applicability.     

航空煤油的羟丙基纤维素凝胶力学性能研究

采用软固体测定仪，研究了胶凝剂、表面活性剂、稳定剂用量对航空煤油凝胶力学性能的影响。结果表明在实验条件下，随胶凝剂用量和表面活性剂OP-10用量的增加，凝胶的屈服应力增加。引入稳定剂C可使凝胶形成时间显著缩短，抗剪切能力显著增强。     

Sol–gel fabrication and enhanced optical properties,photocatalysis, and surface wettability of nanostructured titanium dioxide films

TiO₂ photocatalytic film, annealed at temperatures of 500 °C and 700 °C, was prepared on SiO₂ pre-coated glass via sol–gel technique for photocatalytic purposes and effects of catalyst-type on its properties were investigated by an X-ray diffractometer (XRD), Scanning Electron Microscope, UV–vis spectrophotometer, and contact angle measurements. The XRD results showed that present phases depend upon catalyst used in the solution and phase transformation behaves in a temperature-dependent manner. For the layers derived from sols containing acidic catalysts, the anatase structure dominated and exhibited much better photocatalytic activity. The results indicated that the sample derived from sol comprises H₂SO₄ as catalyst, and exhibits anatase grains with the lowest size. This could be the reason for its better photocatalytic activity. Finally, samples derived from sol containing acidic catalysts showed superhydrophilicity and superior cleaning ability.     

RhB／SiO2凝胶的吸收与发射光谱

将有机染料若丹明B（RhB)以溶胶－凝胶方法镶嵌于SiO2凝胶载体中，测量了样品的吸收光谱和发光光谱。发现，以凝胶玻璃作载体，染料的集聚程度降低，发光光谱发生红移，认为，与凝胶介孔的弱极性环境和激发态分子的偶极矩的减小有关。     

The effect of ethylene glycol/citric acid molar ratio in the initial precursor of TiO2 nanoparticle paste synthesized by a polymerizable complex method on the photovoltaic properties of dye-sensitized solar cells

A polymerizable complex method, also known as a Pechini method, was employed to synthesize titanium-sol (Ti-sol) as a matrix for TiO₂ nanoparticle paste, suitable for fabrication of semiconducting mesoporous TiO₂ layer as a photoanode of dye-sensitized solar cells (DSSCs). The purpose of the present work was to investigate the effect of ethylene glycol (EG)/citric acid (CA) molar ratio (Z), in the initial Ti-sol precursor, on the photovoltaic properties of DSSCs. From viscosity (µ) measurement and Fourier transform infrared (FTIR) spectrum of Ti-sols it was revealed that the amount of polyester in the sol decreases with increasing Z. The higher polyester content in the Ti-sols with lower Z ratios led to their higher surface tension (γ) and as a result the higher contact angle (α). The low wettability of fluorine doped tin oxide (FTO) coated glass with Ti-sol was the main reason of micro-cracking of TiO₂ layers after sintering. This effect was significant for lower Z ratios. Micro-cracks increase the back electron–hole recombination rate. Also, at higher Z ratio, the back electron–hole recombination rate increased, which was due to the lower Ti⁴⁺ ions in the Ti-sol precursor and poor interconnection between TiO₂ nanoparticles. Therefore, the maximum short circuit current density (I_sc) and the maximum conversion efficiency (η) were obtained for Z=4. Fill factor (FF) decreased with increasing Z. But, open circuit voltage (V_oc) was nearly independent of Z.     

Facile deposition of ZnO:Cu films: Structural and optical characterization

Sol–gel technology has been applied for preparation of ZnO:Cu films. The proposed facile approach allows obtaining a wide variety of copper doped zinc oxide systems, revealing different structural and optical behaviors. The work presents structural and optical studies depending on Cu concentration and thermal treatments in the range of 500–800 °C. The structural analysis is performed by X-Ray diffraction (XRD). It reveals that small Cu addition enhances the film crystallization. Increasing copper concentration results in deterioration of ZnO:Cu crystallization. XRD study manifests no Cu oxide phases in ZnO:Cu film structure for lower Cu additions. For a specific higher copper concentration, an appearance of a small fraction of copper oxide is detected. Vibrational properties have been characterized by FTIR spectroscopy. The effect of the copper introduction into ZnO reveals a slight change of optical properties compared to ZnO films for certain Cu ratios. ZnO:Cu films with higher copper contents manifest different optical behaviors with very high transparency in spectral visible range.     

Zirconium oxide dielectric layer grown by a surface sol–gel method for low-voltage,hysteresis-free,and high-mobility polymer field effect transistors

A simple, facile surface sol–gel method is introduced for the fabrication of zirconium oxide films for use as a dielectric layer of a solution-processed polymer field effect transistor (PFET). High dielectric strength is demonstrated for a zirconium oxide layer under room-temperature fabrication conditions using a surface sol–gel method without any post-treatments, which are typically needed in general sol–gel methods. X-ray photoemission spectroscopy showed that the fabricated zirconium oxide layer consists of inorganic ZrO₂ and organic alkoxide groups, which can explain its marginal dielectric constant (∼9) and continuous film properties. In addition, by finishing the surface sol–gel synthesis at the stage of chemisorption, the hydrophobic nature of the final surface was retained, leading to a trap-free semiconductor/dielectric interface. As a result, the PFET made with a conventional polymeric semiconductor rendered nearly hysteresis-free and high mobility (0.3 cm²/V) characteristics at low voltage (<2 V).     

Magnetocontrollable Droplet and Bubble Manipulation on a Stable Amphibious Slippery Gel Surface

Smart manipulation of liquid/bubble transport has garnered widespread attention due to its potential applications in many fields. Designing a responsive surface has emerged as an effective strategy for achieving controllable transport of liquids/bubbles. However, it is still challenging to fabricate stable amphibious responsive surfaces that can be used for the smart manipulation of liquid in air and bubbles underwater. Here, amphibious slippery surfaces are fabricated using magnetically responsive soft poly(dimethylsiloxane) doped with iron powder and silicone oil. The slippery gel surface retains its magnetic responsiveness and demonstrates strong affinity for bubbles underwater but shows small and switching resistance forces with the water droplets in air and bubbles underwater, which is the key factor for achieving the controllable transport of liquids/bubbles. On the slippery gel surface, the sliding behaviors of water droplets and bubbles can be reversibly controlled by alternately applying/removing an external magnetic field. Notably, compared with slippery liquid‐infused porous surfaces, the slippery gel surface demonstrates outstanding stability, whether in air or underwater, even after 100 cycles of alternately applying/removing the magnetic field. This surface shows potential applications in gas/liquid microreactors, gas–liquid mixed fluid transportation, bubble/droplet manipulation, etc.     

Gold‐Nanoparticle‐Doped TiO2 Semiconductor Thin Films: Optical Characterization

A simple procedure for creating titania sol–gel‐based semiconductor thin films is described. Gold nanoparticles are doped homogeneously into the precursor mixture and the particles are homogeneously distributed in the resultant films when prepared using spin‐coating. The effects of particle loading and annealing temperature on the optical properties of the resultant films are characterized. Ellipsometry, X‐ray diffraction, atomic force microscopy, and surface plasmon spectroscopy are used to monitor the crystallization and porosity changes during film synthesis.