UV curing-assisted 3D plotting of ceramic feedstock containing thermo-regulated phase-separable,photocurable vehicle for dual-scale porosity structure

We propose a novel approach for manufacturing dual-scale porosity alumina structures by UV curing-assisted 3D plotting of a specially formulated alumina feedstock using a thermo-regulated phase separable, photocurable camphene/triethylene glycol dimethacrylate (TEGDMA) vehicle. In particular, 3D plotting process was conducted at - 5 °C, and thus an alumina suspension prepared using liquid camphene/TEGDMA at room temperature could undergo phase separation, resulting in camphene crystals surrounded by walls comprised of liquid photopolymer enclosing alumina particles. To enhance the shape retention ability of extruded filaments, polystyrene (PS) polymer was used as the tackifier. The phase-separated feedrod could be extruded favorably through a nozzle and rapidly photopolymerized by UV light during the 3D plotting process. Three-dimensionally interconnected macropores were tightly constructed, which were separated by microporous alumina filaments, where micropores were created by the removal of camphene crystals via freeze-dying. The macroporosity of porous alumina ceramics was controlled by adjusting the distance between deposited filaments, while their microporosity was kept constant, leading to tightly tailored overall porosity and mechanical properties.     

The application of photography in investigating fraud

The impact of fraud on the world economy is significant. As fraud has evolved it has become more organized and increasingly cyber-enabled and committed across borders of law enforcement jurisdictions. The technological demands facing fraud investigators are increasing. Yet, little attention has been given to how forensic photography can help tackle emerging crime types, like fraud. This study reviews literature surrounding forensic photography and provides an up to date and collective narrative. This article focuses on the advancements in photography and how imaging-science techniques can apply to a fraud investigation. Photographic practice plays a key role in many crime investigations but must embrace continual change to ensure that it remains relevant to modern policing. Fresh approaches are essential and practitioners must fully utilize new technologies and adapt to tackle the increasingly demanding scope of fraud types.     

指甲花叶色素对涤纶织物染色及防紫外线整理

文中研究了指甲花叶色素对涤纶织物染色及防紫外线整理,首先探讨了涤纶织物高温高压指甲花叶色素直接染色的较优工艺,并以硫酸铝钾和单宁酸作为媒染剂对织物进行后媒染色,探讨了媒染剂媒染对染色性能及防紫外线效果的影响。结果表明,指甲花色素对涤纶织物高温高压直接染色工艺较优条件为:染色温度125℃、染色时间60 min、染液浓度30 g/L和pH值=3,染色后织物耐皂洗色牢度和耐摩擦色牢度满足穿着要求,且具有一定的防紫外线性能;硫酸铝钾和单宁酸作为媒染剂对涤纶织物后媒染色有利于提升指甲花叶色素上染涤纶织物的效果及防紫外线能力。     

UV-enhanced conductive and dielectric properties in KTN crystal

We observe enhancements of both conductive and dielectric properties under UV illumination by using a ferroelectric absorber, potassium tantalate niobate (KTa_1-xNb_xO₃, KTN). The UV-generated electron-hole pairs weaken the intrinsic ferroelectric polarization while enhance the conductive property. The UV-induced heat effect causes the enhancement of the dielectric property. The results are further confirmed by the maximal rectification ratio which shows an opposite trend between the direct heating process and the UV illumination. Our results are useful for better understanding of ferroelectric properties under UV illumination and the development of new optoelectronic devices.     

纳米ZnO/有机氟改性丙烯酸酯乳液的合成与表征

以纳米ZnO、甲基丙烯酸十二氟庚酯(DFMA)、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为原料,用半连续种子乳液聚合法制备纳米ZnO/有机氟改性聚丙烯酸酯,探索了合成工艺,然后将合成乳液用于亚麻织物的整理。采用FT-IR、XPS和SEM等方法对乳胶膜和整理后的织物进行表征分析。结果表明:当乳化剂质量分数为4%,引发剂质量分数为1.5%,反应温度为80℃,保温时间为60 min时,乳液的合成效果最好。合成的乳液具有良好的抗紫外性能,其乳胶膜的吸水率为8.64%。XPS和SEM测试结果显示,合成的复合乳液和织物相结合,提高了亚麻织物的疏水性。相比聚丙烯酸酯整理后的织物,经复合乳液整理后的亚麻织物对水的接触角提高了60.4°。     

Solution processed,vertically aligned,AZO nanocolumn array for chemiresistive sensor application with UV-enhanced sensitivity

In this work, a wide and highly sensitive chemiresistive sensor has been developed based on the AZO nanocolumn array film. This is meant for the room detection of H₂O₂ under UV illumination. A cost-effective one step multi-layers growth process was adopted for the synthesis of the AZO nanocolumn array. The experimental studies were done by scanning electron microscopy (SEM), transmission and electron microscopy (TEM).Then X-ray diffraction confirmed that the AZO column array was closely packed, connected, vertically aligned, and polycrystalline, with a high surface area. This structure ensures better electrical conduction over random and separated nanostructures. The hall-effect measurement indicates that the AZO film was n-type, with high conductivity (3.60 × 10³ Ωcm), high carrier density (11.3 × 10²⁰cm⁻³) and with acceptable mobility (0.95 cm²/Vs). The x-ray photoemission spectroscopy suggests that the AZO film consists of a large amount of adsorbed oxygen-related species at the sheath layer of the thin-film, which is vital for sensors. By the UV light activation, sensors based on the AZO nanocolumn array exhibited enhanced H₂O₂ detection properties at room temperature. At a concentration from 15 μM to 30 mM, H₂O₂ sensitivity evaluated by relative response was remarkably increased from 15% to 36%. The operation under ambient conditions and wide range sensing shows that this chemiresistive AZO sensor is adequate for biomedical and environmental applications.