聚酯表面的生物技术改性

合成纤维是纺织工业的重要组成部分。合成纤维的缺点是其亲水度低,PET纤维特别疏水,这影响纤维的加工性和功能性。比较新颖、有前途、可供选择的方法是酶用于合成纤维的表面改性。已经报道,用酶水解酯键,从而提高聚酯的亲水度。这一促进功能化的过程,目标是用现代的生物技术使PET纺织材料功能化。结果将形成新的特定知识和技术,产生用生物技术改性的纺织材料,从而有助于向生物型经济转变。

采用水基前驱溶液喷墨印刷制备光催化活性TiO_2薄膜

近年来,作为一种高能量带隙半导体,二氧化钛(TiO_2)由于在紫外光照射下具有良好的光催化活性,已引起科研人员的广泛关注。由于TiO_2无色透明,具有广泛的应用前景,如薄的TiO_2涂层可用于创建自清洁、防雾、超亲水表面。同时,也能用于太阳能电池等光电子行业。

A strategy for enhancing luminescence thermometry via Ta^(5+)-triggered K_(0.5)Na_(0.5)NbO_(3):Er^(3+)transparent ceramics

Luminescence thermometry is a reliable approach for remote thermal sensing,and extensive studies have been devoted to designing a luminescence thermometer with heightened thermal sensitivity.Herein,we report a promising luminescence thermometric material,Ta^(5+)-substituted K_(0.5)Na_(0.5)NbO_(3):0.003Er^(3+)transparent ferroelectric ceramics.The temperature sensing sensitivity is significantly improved by adjusting the concentration of Ta^(5+)in the material.Specifically,utilizing the fluorescence intensity ratio from the 2H_(11/2) and 4S_(3/2) thermally coupled states of Er^(3+)as a detecting signal within the temperature range of 273–543 K,an optimal maximum absolute sensitivity of 0.0058 K–1 and relative sensitivity of 0.0158 K–1 are achieved for K_(0.5)Na_(0.5)NbO_(3):0.65Ta^(5+)/0.003Er^(3+).Simultaneously,as the concentration of Ta5+increase,a unique evolution of structural phase transitions is observed from orthorhombic to tetragonal and then to cubic.This is accompanied by an improvement in luminescence temperature sensing properties,and the best sensitivity is demonstrated in the cubic-phase region.Intriguingly,a huge change in infrared luminescence properties as a function of temperature is found around the structure transition temperature of the samples.These results indicate a promising potential for achieving highly sensitive thermometry or monitoring phase structure transitions through luminescence thermometry behavior in the K_(0.5)Na_(0.5)NbO_(3) host.

Adding memory to pressure-sensitive phosphors

Mechanoluminescence(ML)is the phenomenon describing the emission of light during mechanical action on a solid,leading to applications such as pressure sensing,damage detection and visualization of stress distributions.In most cases,this mechanical action releases energy that was previously stored in the crystal lattice of the phosphor by means of trapped charge carriers.A drawback is the need to record the ML emission during a pressure event.In this work,we provide a method for adding a memory function to these pressure-sensitive phosphors,allowing an optical readout of the location and intensity of a pressure event in excess of 72 h after the event.This is achieved in the BaSi_(2)O_(2)N_(2):Eu^(2+) phosphor,where a broad trap depth distribution essential for the process is present.By merging optically stimulated luminescence(OSL),thermoluminescence(TL)and ML measurements,the influence of light,heat and pressure on the trap depth distribution is carefully analysed.This analysis demonstrates that mechanical action can not only lead to direct light emission but also to a reshuffling of trap occupations.This memory effect not only is expected to lead to new pressure sensing applications but also offers an approach to study charge carrier transitions in energy storage phosphors.

Photoreceptor-Mediated Bending towards UV-B in Arabidopsis

Plants reorient their growth towards light to optimize photosynthetic light capture--a process known as phototropism. Phototropins are the photoreceptors essential for phototropic growth towards blue and ultraviolet-A （UV- A） light. Here we detail a phototropic response towards UV-B in etiolated Arabidopsis seedlings. We report that early differential growth is mediated by phototropins but clear phototropic bending to UV-B is maintained in photl phot2 double mutants. We further show that this phototropin-independent phototropic response to UV-B requires the UVoB photoreceptor UVR8. Broad UV-B-mediated repression of auxin-responsive genes suggests that UVR8 regulates directional bending by affecting auxin signaling. Kinetic analysis shows that UVR8-dependent directional bending occurs later than the phototropin response. We conclude that plants may use the full short-wavelength spectrum of sunlight to efficiently reorient photosynthetic tissue with incoming light.

Hybrid remote quantum dot/powder phosphor designs for display backlights

Quantum dots are ideally suited for color conversion in light emitting diodes owing to their spectral tunability,high conversion efficiency and narrow emission bands.These properties are particularly important for display backlights;the highly saturated colors generated by quantum dots justify their higher production cost.Here,we demonstrate the benefits of a hybrid remote phosphor approach that combines a green-emitting europium-doped phosphor with red-emitting CdSe/CdS core/shell quantum dots.Different stacking geometries,including mixed and separate layers of both materials,are studied at the macroscopic and microscopic levels to identify the configuration that achieves maximum device efficiency while minimizing material usage.The influence of reabsorption,optical outcoupling and refractive index-matching between the layers is evaluated in detail with respect to device efficiency and cost.From the findings of this study,general guidelines are derived to optimize both the cost and efficiency of CdSe/CdS and other(potentially cadmium-free)quantum dot systems.When reabsorption of the green and/or red emission is significant compared to the absorption strength for the blue emission of the pumping light emitting diode,the hybrid remote phosphor approach becomes beneficial.