Deacetylated Cellulose Acetate/Polyurethane Composite Nanofiber Membranes with Highly Efficient Oil/Water Separation and Excellent Mechanical Properties

Nowadays, oil pollution has become more serious, which causes great threats both to the ecological environment and human life. In this study, a novel type of multifunctional deacetylated cellulose acetate/polyurethane (d-M_CA:M_TPU) composite nanofiber membranes for oil/water separation are successfully fabricated by electrospinning, which show super-amphiphilicity in air, super-hydrophilicity in oil, and oleophobicity in water. All the d-M_CA:M_TPU composite nanofiber membranes with different mass ratios can be used as water-removing, oil-removing, and emulsion separation substance only by gravity driving force. The highest separation flux for water and oil reaches up to 37 000 and 74 000 L m⁻² h⁻¹, respectively, and all the separation efficiencies are more than 99%. They have outstanding comprehensive mechanics performance, which can be controlled by simply adjusting the mass ratios. They show excellent antifouling and self-cleaning ability, endowing powerful cyclic stability and reusability. Those results show that d-M_CA:M_TPU composite nanofiber membranes have great application prospects in oil/water separation.     

Organic Semiconducting Luminophores for Near-Infrared Afterglow,Chemiluminescence, and Bioluminescence Imaging

Optical imaging has played a pivotal role in deciphering in vivo bioinformatics but is limited by shallow penetration depth and poor imaging performance owing to interfering tissue autofluorescence induced by concurrent photoexcitation. The emergence of near-infrared (NIR) self-luminescence imaging independent of real-time irradiation has timely addressed these problems. There are two main kinds of self-luminescent agents, namely inorganic and organic luminophores. Inorganic luminophores usually suffer from long-term biotoxicity concerns resulting from potential heavy-metal ions leakage and nonbiodegradability, which hinders their further translational application. In contrast, organic luminophores, especially organic semiconducting luminophores (OSLs) with good biodegradable potential, tunable design, and outstanding optical properties, are preferred in biological applications. This review summarizes the recent progress of OSLs used in NIR afterglow, chemiluminescence, and bioluminescence imaging. Molecular manipulation and nanoengineering approaches of OSLs are discussed, with emphasis on strategies that can extend the emission wavelength from visible to NIR range and amplify luminescence signals. This review concludes with a discussion of current challenges and possible solutions of OSLs in the self-luminescence field.     

How scientific research incorporates policy: an examination using the case of China’s science and technology evaluation system

Scientometrics - Governments typically formulate sets of policies to guide the direction of scientific research. And the possible effects of these policies on scientific research have been...     

Fabrication of Anticounterfeiting Nanocomposites with Multiple Security Features via Integration of a Photoresponsive Polymer and Upconverting Nanoparticles

Anticounterfeiting materials are used to distinguish real banknotes, products, and documents from counterfeits, fakes, or unauthorized replicas. However, conventional anticounterfeiting materials generally exhibit a single anticounterfeiting function, resulting in a low level of security. Herein, a novel anticounterfeiting nanocomposite is demonstrated with numerous prominent security features. The nanocomposite is fabricated by doping upconverting nanoparticles (UCNPs) in a photoresponsive azobenzene-containing polymer (azopolymer). Because of the cis–trans photoisomerization of the azopolymer, the nanocomposite exhibits photoinduced reversible color changes suitable for anticounterfeiting applications. Additionally, the hard nanocomposite can be converted to a rubber-like soft solid by light irradiation. Imprinted microstructures are fabricated on the photosoftened nanocomposite, which result in photonic colors. Moreover, polarization-dependent structures are fabricated on the nanocomposite via photoinduced orientation for encryption. Importantly, UCNPs in the nanocomposite emit visible light upon excitation by near-infrared light, enabling the observation of various anticounterfeiting structures with high contrast. An advantage of the anticounterfeiting nanocomposite is that the security features can be observed by the naked eye for quick discrimination and can be analyzed using laboratory equipment for higher accuracy. The anticounterfeiting nanocomposite is easily processed on paper, glass, and plastic, which demonstrates its potential anticounterfeiting functions for banknotes, wines, and medicines.     

膜分离与醇沉技术纯化猴头菇粗多糖的比较

研究膜分离和醇沉两种技术对猴头菇粗多糖分离效果及其抗氧化活性的影响。以猴头菇子实体为原料,通过热水浸提后分别用醇沉、纳滤、纳滤+醇沉、微滤+纳滤、微滤+纳滤+醇沉5种方法得到猴头菇粗多糖,分别记为A-He P、B-He P、C-He P、D-He P和E-He P。比较5种方法对猴头菇粗多糖的分离纯化效果、理化性质和抗氧化活性的差异。结果表明,微滤+纳滤技术分离纯化效果较好,其粗多糖得率为10.08%,纯度为43.01%,提取液中80.34%的多糖得到保留。经傅里叶变换红外光谱分析,5种工艺处理获得的粗多糖样品均具有典型的吡喃型葡聚糖和β-型糖苷键吸收峰。5种处理获得的粗多糖样品中均含一定量的蛋白质,且B-He P的蛋白质量分数高于C-He P,说明微滤处理可以除去部分蛋白而提高多糖的纯度。还原力、·OH、2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)二铵盐阳离子自由基、1,1-二苯基-2-三硝基苯肼自由基清除结果表明,5种粗多糖样品均具有一定的抗氧化能力,且D-He P的抗氧化能力最佳。     

香蕉米酒酿造工艺的响应面法优化

采用单因素试验法,探讨鱼糜添加量、冰水添加量和素肉粉添加量3个因素对鱼肉饺皮感官评分的影响。通过响应曲面分析法对鱼肉饺皮的感官评分和弹性进行优化,得到鱼肉饺皮制作的最优工艺是:鱼糜添加量58.76%、冰水添加量14.16%、素肉粉添加量2.02%。在此条件下鱼肉饺皮的感官评分为91,弹性为0.819,大肠菌群呈阴性。     

Advances in reduction of NOx and N2O1 emission formation in an oxy-fired fluidized bed boiler

Fossil fuel combustion is one of the major means to meet the mounting global energy demand. However, the increasing NO_x and N₂O emissions arising from fossil fuel combustion process have hazardous effects. Thus, mitigating these gases is vital to attain a sustainable environment. Interestingly, oxy-fuel combustion in fluidized bed for carbon capture and minimized NO_x emissions is strongly sustainable compare to the other approaches. It was assessed that NO_x formation and fuel-N conversion have significant limitation under oxy-fluidized bed compared to air mode and the mechanism of NO_x formation is still deficient and requires further development. In addition, this review paper discussed the potential of primary measure as low emission process with others supplementary techniques for feasible NO_x reduction. The influences of combustion mode, operating parameters, and reduction techniques such as flue gas recirculation, oxygen staging, biomass co-firing, catalyst, influence of fluidized bed design and structure, decoupling combustion and their merges are respectively evaluated. Findings show that significant minimization of NO_x emission can be achieved through combination of primary and secondary reduction techniques.     

Band gap narrowing and electrical properties of (1-x)BaTiO3-xSrFe0.5Nb0.5O3 lead-free ceramics

Journal of Materials Science: Materials in Electronics - The composite materials in the form of (1-x)BaTiO3-xSrFe0.5Nb0.5O3((1-x)BT-xSFN) are synthesized via the solid-state reaction route....     

Aqueous dispersion of 1D van der Waals Mo6S3I6 crystal using biocompatible tri-block copolymer

To achieve the stable dispersion of 1D van der Waals crystal Mo₆S₃I₆ in aqueous media, the tri-block copolymer (Poloxamer) is used as dispersant. The head group of Poloxamer, hydrophobic polypropylene oxide parts can be adsorbed to Mo₆S₃I₆ surface by hydrophobic interaction and the tail group with hydrophilic polyethylene oxide exposed to the outside of the Mo₆S₃I₆ is soluble in water and can form sufficient steric hindrance, resulting in stable aqueous dispersion in nm scale. The excellent biocompatibility of aqueous dispersed nm scale 1D Mo₆S₃I₆ was demonstrated by effective proliferation of C2C12 cells.     

激光刻痕对取向电工钢磁畴和铁损的影响

为了研究激光刻痕工艺参数对取向电工钢表面的磁畴形貌、刻痕线宽度和铁损的影响规律，开展了激光刻痕工艺试验。结果表明，激光刻痕后取向电工钢表面的磁畴宽度明显细化，且随着输入电流的增加，磁畴宽度先减小后增大；刻痕线宽度随着输入电流的增加而增大。对于本次试验样品，通过对比分析，确定最佳激光刻痕工艺参数为电流为 12 A，激光频率为 5 kHz，刻痕速度为 800 mm/s，该参数下铁损改善率可达 11.81%。