Preparation of molecularly imprinted fluorescence sensor based on carbon quantum dots via precipitation polymerization for fluorescence detection of tetracycline

A facile and effective method was proposed to prepare the molecularly imprinted fluorescence sensor with carbon quantum dots, which were modified vinyl groups by acrylic acid on the surface. The obtained fluorescence composite material was investigated by transmission electron microscope and Fourier transform infrared spectra. After the experimental conditions were optimized, a linear range of 1.0–60 μmol L⁻¹ was obtained and the detection limit was 0.17 μmol L⁻¹. The novel fluorescence sensor can be successfully used to detect tetracycline in real samples. This study provides a convenient strategy for selective recognition and rapid detection of tetracycline in the complex environment.     

The growth of oleaginous Rhodotorula glutinis in an internal-loop airlift bioreactor by using mixture substrates of rice straw hydrolysate and crude glycerol

The conversion of lignocellulosic biomass (LCB) to microbial oils is attracting a growing amount of attention. However, the growth of the oleaginous yeast Rhodotorula glutinis on LCB hydrolysate (mainly rice straw) only will lead to a low lipid mass fraction, in the range of 10–20%. This study shows that the addition of crude glycerol to the LCB hydrolysate medium can efficiently raise the lipid mass fraction to the range of 30–40%. Crude glycerol is a by-product in the biodiesel production process. The use of renewable LCB hydrolysate and crude glycerol would greatly reduce the substrate cost for microbial oil production using R. glutinis. In addition, the results of experiments show that a low-cost airlift bioreactor is a more suitable fermentation process for the growth of R. glutinis than the use of a conventional agitation tank. When using mixed carbon sources of LCB hydrolysate with 30 kg m⁻³ of reducing sugars and 30 kg m⁻³ of crude glycerol, a maximal cell mass of 21.4 kg m⁻³ and lipid mass fraction of 58.5 ± 6.2 were achieved in an internal loop airlift bioreactor, and this process may have the potential to be applied in scale-up production.     

DP980+Z烘烤硬化值与退火温度的关系

摘要：为了研究退火温度对镀锌DP980+Z烘烤硬化值的影响，退火温度控制在760～820℃之间，系统分析退火温度对烘烤硬化值的影响。通过准静态拉伸试验机测量烘烤硬化值及抗拉强度，采用lepara试剂对组织中的马氏体进行着色，利用金相显微镜及图像处理软件测量马氏体的体积分数；采用扫描电镜观察DP980+Z的双相组织特点，并且将组织图片通过CAD转化成有限元图进行网格划分，建立代表性体积单元（RVE），通过有限元分析铁素体、马氏体强度对烘烤硬化值的影响。在同样的变形量情况下，DP980+Z的原始屈服强度越高，烘烤硬化值越高。     

碳基采暖电热材料研究进展

近几年,由于节能与环保的需求,电取暖的方式得到大力的推广,电热材料的研究与应用受到人们广泛的重视。非金属碳基电热材料是新型的节能型电热采暖材料,本文重点对影响非金属碳基电热材料中的炭黑基电热材料、碳纤维基电热材料、碳晶电热材料电热性能的因素及相关应用进行了综述。     

Effect of residual excess carbon on the densification of ultra-fine HfC powder

The residual carbon content of ultra-fine hafnium carbide (HfC) powder was controlled by the optimization of the synthesis process, and the effect of residual carbon on the densification of HfC powder was analyzed. The amount of residual carbon in the HfC powder could be reduced by the de-agglomeration of HfO₂ powder before the carbo-thermal reduction (CTR) process. The average particle size of HfO₂ powder decreased from 230 to 130 nm after the de-agglomeration treatment. Ultra-fine (d₅₀: 110 nm) and highly pure (metal basis purity: >99.9 % except for Zr) HfC powder was obtained after the CTR at 1600 °C for 1 h using the C/Hf mixing ratio of 3.3. In contrast, the C/Hf ratio increased to 3.6 without the de-agglomeration treatment, indicating that a large amount of excess carbon was required for the complete reduction of the agglomerated HfO₂ particles. HfC ceramics with high relative density (>98 %) were obtained after spark plasma sintering at 2000 °C under 80 MPa pressure when using the HfC powder with low excess carbon content. In contrast, the densification did not complete at a higher temperature (2300 °C) and pressure (100 MPa) when the HfC powder contained a large amount of residual carbon. The results clearly indicated that residual carbon suppressed the densification of HfC powder in case the carbide powder had low oxygen content, and the residual carbon content could be controlled by the optimization of the synthesis process. The average grain size and Vickers hardness of the sintered specimen were 6.7(±0.7) μm and 19.6 GPa, respectively.     

Advanced Surface of Fibrous Activated Carbon Immobilized with FeO/TiO2 for Photocatalytic Evolution of Hydrogen under Visible Light

FeO-doped TiO₂ nanoparticle photocatalysts were immobilized onto the surface of fibrous activated carbon (ACF) via a sol-gel process. As an adsorbent and photocatalyst, FeO-TiO₂ on immobilized ACFs (FeO-TiO₂/ACF) greatly improved the photocatalysis rate of hydrogen production as compared with pure TiO₂ and ACF-TiO₂ under UV irradiation and visible light. The addition of ACFs surface significantly reduced the photogenerated pairs of electrons-hole recombination, thereby promoting the photocatalysis action of doped photo-metal oxides of FeO-TiO₂. Co-doping of FeO onto the lattice of the TiO₂ approach can improve the absorption activity of visible light through photo-metal oxide of TiO₂ and further enhance hydrogen production under visible light. The photocatalytic fabrics (FeO-TiO₂/ACF) were effortlessly split out from the experimental solution for re-utilization and exhibited high stability even after five complete regeneration cycles.     

生物可降解PCL/PLA开孔发泡材料制备及吸油性能

以聚己内酯（PCL）为基体，添加不同含量聚乳酸（PLA）熔融共混制备具有不同分散相形态的PCL/PLA共混物，利用超临界二氧化碳（scCO₂）微孔发泡工艺制备不同发泡倍率和开孔率的PCL/PLA多孔材料用于吸油应用。针对边长3 mm正方体样品溶解度实验发现100 min后CO₂在PCL中已达到饱和吸附状态。PLA分散相含量的增加显著增大了PCL/PLA共混物泡孔密度，并使共混泡孔尺寸减小且分布更加均匀；发泡温度升高6℃，泡孔尺寸增大50%，发泡倍率增大38%，开孔率减小了20%。PCL/PLA开孔材料具有明显的亲油疏水性，发泡倍率越高，疏水性越好；针对花生油和硅油的吸油实验发现材料吸油率与发泡倍率和开孔率整体呈正比，实际吸油量高于理论计算值，10次循环吸油测试后样品吸油率仅降低8.5%，材料吸油量与油品特性黏度关系不大。     

高分散度Pt/C电催化剂的制备

Cabot公司Vulcan XC-72型炭黑，经过H2O2氧化处理后作为Pt的载体，H2PtCl6作为金属前驱体制备了高度分散的Pt/C催化剂。讨论了不同条件下H2PtCl6在炭黑上的吸附性能。载体经过H2O2氧化处理24h,H2PtCl6在pH=9下吸收48h，H2 350℃还原2h，可以制备出铂晶粒平均大小为1.8nm的Pt/C电催化剂。     

Capture of Organic Vapors Using Adsorption and Electrothermal Regeneration

Activated-carbon-fiber cloth (ACFC) is an alternative adsorbent to granular activated carbon (GAC) for removing and recovering organic vapors from gas streams. Electrothermal desorption (ED) of ACFC provides rapid regeneration while requiring less energy compared to traditional regeneration techniques used with GAC. This paper provides proof-of-concept results from a bench-scale ACFC adsorption system. The automated system captured 1,000 ppmv of hazardous air pollutants/volatile organic compounds (HAPs/VOCs) from air streams and demonstrated the use of ED, using ac voltage, to recover the HAP/VOC as a pure liquid. The desorbed HAP/VOC condensed onto the inner walls of the adsorber and was collected at the bottom of the vessel, without the use of ancillary cooling. Seventy percent of the HAP/VOC was collected per cycle as condensate, with the balance being retained in the regenerated adsorber or recycled to the second adsorber. ED with in-vessel condensation results in minimal N2 consumption and short regeneration cycle times allowing the process to be cost competitive with conventional GAC-based adsorption processes. This technology extends the application of carbon adsorption systems to situations that were previously economically and physically impractical.     

Annealing effects on structural and electrical properties of fluorinated amorphous carbon films deposited by plasma enhanced chemical vapor deposition

The annealing effects on the structural and electrical properties of fluorinated amorphous carbon (a-C:F) thin films prepared from C₆F₆ and Ar plasma are investigated in a N₂ environment at 200 mTorr. The a-C:F films deposited at room temperature are thermally stable up to 250 °C, but as the annealing temperature is increased beyond 300 °C, the fluorine incorporation in the film is reduced, and the degree of crosslinking and graphitization in the film appears to be enhanced. At the annealing temperature of 250 °C, the chemical bond structures of the film are unchanged noticeably, but the interface trapped charges between the film and the silicon substrate are reduced significantly. The increased annealing temperature contributes the decrease of both the interface charges and the effective charge density in the a-C:F film. Higher self-bias voltage is shown to reduce the charge density in the film.