Bioinspired and Mechanically Strong Fibers Based on Engineered Non-Spider Chimeric Proteins

Silk-protein-based fibers have attracted considerable interest due to their low weight and extraordinary mechanical properties. Most studies on fibrous proteins focus on the recombinant spidroins, but these fibers exhibit moderate mechanical performance. Thus, the development of alternative structural proteins for the construction of robust fibers is an attractive goal. Herein, we report a class of biological fibers produced using a designed chimeric protein, which consists of the sequences of a cationic elastin-like polypeptide and a squid ring teeth protein. Remarkably, the chimeric protein fibers exhibit a breaking strength up to about 630 MPa and a corresponding toughness as high as about 130 MJ m⁻³, making them superior to many recombinant spider silks and even comparable to some native counterparts. Therefore, this strategy is a novel concept for exploring bioinspired ultrastrong protein materials through the development of new types of structural chimeric proteins.     

Simultaneously improving flame retardancy and dynamic mechanical properties of epoxy resin nanocomposites through synergistic effect of zirconium phenylphosphate and POSS

Journal of Thermal Analysis and Calorimetry - To simultaneously improve flame retardancy and dynamic mechanical properties of epoxy resin (EP) nanocomposites, layered zirconium phenylphosphate...     

北京一次小震级地震前异常声-重力波产生机理的研究

观测到北京一次小震级地震(ML=3.0)前的异常声-重力波,并同时记录到异常地表倾斜信号。二者相关系数比较高,在接近震中的地区相关系数达到最大值0.5,相关系数随着远离震中的距离增大而减小。经过研究表明,异常声-重力波的产生与震前的地表缓慢活动引发的山体缓慢晃动导致的气流风速波动变化有关。基于350 m高的气象铁塔观测的风速数据,对两层大气模型传播的声-重力波进行了数值计算,得到的相对山体非平稳气流引起的声-重力波与观测信号在特征周期、幅度和速度三个参数上近似。以地表倾斜为例的模型与观测数据的一致性表明该震前声-重力波与地震存在关联性。      

多巴胺基纳米材料在生物医药中的应用

多巴胺是存在于人体内的一种儿茶酚胺类神经递质。自从研究者们发现了利用多巴胺的氧化自聚合反应制备聚多巴胺涂层的简便方法之后,多巴胺基纳米材料已经发展成为一类新兴的生物材料。多巴胺基纳米材料由于具有独特的物理化学性质,例如普适性的粘附性质、高化学反应活性、优良的生物相容性和生物降解性、以及光热转换性质,而在生物传感、药物输送、光热疗法、抗菌和组织工程等领域吸引了研究者们强烈的研究兴趣。本文综述了多巴胺基纳米材料的制备、功能化及在生物医药应用方面的最新进展。首先介绍了几种典型的多巴胺基纳米材料,并讨论影响其组装过程的因素。之后详细综述了这些材料在生物医药领域的应用,尤其是在癌症诊断和治疗方面。最后,本文提出了推进多巴胺基纳米材料临床应用需要发展的研究方向。     

Experimental study on physical and mechanical properties and U(VI) leaching characteristics of fiber-reinforced uranium tailing geopolymer-solidified bodies

Journal of Radioanalytical and Nuclear Chemistry - A uranium tailing pond in southern China is the largest in Asia. For historical reasons, uranium tailings stored in the pond have been in an...     

自动驾驶汽车在交通网络中的效能分析

研究了对于三车道的高速公路,自动驾驶汽车对混合交通流的通行能力及安全性的影响。引入变道欲望值、连续刹车率、空间速度方差和时间速度方差的概念,基于交通流元胞自动机模型,针对手动和自动驾驶2种汽车,建立了单向三车道的加减速和换道规则。选取6个评价参数,针对三车道模型,研究了随着自动驾驶汽车比例的增加,车道平均速度、平均速度的方差、交通密度、连续刹车率以及变道次数的变化情况。实验结果表明:在通行能力方面,当自动驾驶汽车的比例持续增加时,整个车道的平均速度、交通密度显著增加,从而大大提高了此交通网路中的通行能力;同时空间速度方差和时间速度方差会显著减少,说明整个交通流的平稳性增加了。在安全表现方面,当自动驾驶汽车的比例持续增加时,整个交通网路中的连续刹车率、变道次数先逐渐增加,然后逐渐减少,从而很好地刻画了安全性。最后分析了模型的优缺点,并指出了改进的方向。     

Detecting nanoparticles by “listening”

In the macroscopic world, we can obtain some important information through the vibration of objects, that is, listening to the sound. Likewise, we can also get some information of the nanoparticles that we want to know by the means of “listening” in the microscopic world. In this review, we will introduce two sensing methods (cavity optomechanical sensing and surface-enhanced Raman scattering sensing) which can be used to detect the nanoparticles. The cavity optomechanical systems are mainly used to detect sub-gigahertz nano particle or cavity vibrations, while surface-enhanced Raman scattering is a well-known technique to detect molecular vibrations whose frequency generally exceeds terahertz. Therefore, the vibrational information of nanoparticles from low-frequency to high-frequency could be obtained by these two methods. The size of the viruses is at the nanoscale and we can regard it as a kind of nanoparticles. Rapid and ultrasensitive detection of the viruses is the key strategies to break the spread of the viruses in the community. Cavity optomechanical sensing enables rapid, ultrasensitive detection of nanoparticles through the interaction of light and mechanical oscillators and surface-enhanced Raman scattering is an attractive qualitatively analytical technique for chemical sensing and biomedical applications, which has been used to detect the SARS-CoV-2 infected. Hence, investigation in these two fields is of vital importance in preventing the spread of the virus from affecting human’s life and health.     

热电制冷模组热端散热器性能优化研究

针对实际项目热电制冷模组进行了三维数值模拟,对比分析断槽数不同的四种典型散热器在不同电流、翅片厚度、断槽宽度下的散热能力,得到了性能较佳的工况与散热器模型.结果 表明,随着电流增加,热电制冷模组冷面温度不断降低,当电流超过一定数值时,冷面温度趋于平衡,热面温度急剧上升.四类散热器中,断槽数为一的散热器散热能力较佳,并对此类散热器的翅片厚度进行优化,在研究范围内,翅片厚度2.5 mm散热效果较佳.断槽宽度有临界值,断槽宽度值小于9 mm时散热器面积减小不会使散热能力减弱,反之大于9 mm时散热能力急剧衰弱,为实际工程的分析提供了借鉴和参考.     

FeOOH photo-deposited perylene linear polymer with accelerated charge separation for photocatalytic overall water splitting

It is a challenge to develop single polymer-based photocatalyst for overall water splitting without adding sacrificial agents due to the insufficient driving force for charge separation and the lack of active sites of organic polymer.Metal oxyhyroxides are widely acted as co-catalyst for photoelectrocatalysis oxygen evolution reaction.Here,we firstly report the peryleno[1,12-bcd]thiophene sulfone-based linear co-polymer PS-5 for photocatalytic overall water splitting by photo-depositing simple and low-cost cocatalyst FeOOH under the visible-light illumination.The density functional theory(DFT)calculations and experimental results indicated clearly that the oxygen vacancies-richβ-FeOOH can effectively promote the separation of photo-generated excitons and provide active sites for photocatalytic oxygen evolution reaction.As a result,the average H₂and O₂production rates of optimized PS-5/β-FeOOH-0.2M reach at~170 and~76.6μmol h^-1g^-1,respectively,with a stoichiometric ratio at about 2:1.This work provides a simple and low-cost method for the preparation of overall water splitting system based on polymer photocatalyst.     

Correction to: First-principles study on the Jahn-Teller distortion in trigonal bipyramidal coordinated LiFe1−xMxBO3 (M=Mn,Co, and Ni) compounds

The development of new cathode materials with high capacity, good stability, and high safety is important for the future improvement of Li batteries. LiFeBO₃ is considered to be a type of promising electrode materials for Li-ion batteries due to its low cost, high theoretical capacity of 220 mAh/g (about 30% larger than that of LiFePO₄), low toxicity, and small volume change of 2% during the Li⁺ reversible extraction/insertion process. However, its electronic conductivity and rate performance still need further improvement. To optimize the performance of the LiFeBO₃, Mn, Cr, and Ni doping at Fe site have been studied experimentally, while the effect of minor addition of 3d transition metals on the electronic structure of LiFeBO₃ is rarely investigated. Thus, density functional theory calculations corrected by on-site Coulomb interactions have been conducted to study the crystal structure and electronic property of the LiFe_1−xM_xBO₃ (M = Mn, Co, and Ni) electrode systems. The results indicate that the coordination geometry about Fe in LiFeBO₃ is a distorted trigonal bipyramid with a distortion which can be attributed to a Jahn-Teller effect. The band gap energy of LiFeBO₃ is calculated to be 3.40 eV, which is in reasonable agreement with the previously computed values. The doping at Fe site with Mn cannot reduce the distortion of Jahn-Teller effect, whereas Co doping intensifies Jahn-Teller distortion of the FeO₅ trigonal bipyramid in LiFeBO₃. Ni substitution is predicted to be able to introduce impurity levels, and the Jahn-Teller distortion degree of the trigonal bipyramid decreased from 11.9 of the FeO₅ to 8.7% of the NiO₅. Thus, Ni doping is expected to increase stability and the electronic conductivity of the LiFeBO₃ structure.