Protein‐Affinitive Polydopamine Nanoparticles as an Efficient Surface Modification Strategy for Versatile Porous Scaffolds Enhancing Tissue Regeneration

Porous scaffolds for tissue regeneration are often functionalized with extracellular matrix proteins to enhance surface/cell interactions and tissue regeneration. However, continuous coatings produced by commonly used surface modification strategies may preclude cells from contacting and sensing the chemical and physical cues of the scaffold. Here, it is shown that polydopamine nanoparticles (PDA‐NPs) tightly adhere on various scaffolds to form nanostructures, and the coverage can be finely tuned. Furthermore, the PDA‐NPs have good affinity to a variety of proteins and peptides. Thus, the PDA‐NPs act as an anchor to immobilize signal biomolecules on scaffolds, and consequently promote cell activity and tissue regeneration. β‐Tricalcium phosphate (TCP) scaffolds decorated with PDA‐NPs demonstrate excellent osteoinductivity and bone‐regeneration performance due to the protein affinity of PDA‐NPs and the intrinsic bioactive characteristics of TCP scaffolds. In summary, PDA‐NPs with excellent affinity for protein adhesion represent a versatile platform to modify porous scaffolds while not compromising the biological functions of the scaffolds, and might have potential applications in tissue regeneration.     

Magnetically‐Confined Fe‐Mn Bimetallic Oxide Encapsulation as an Efficient and Recoverable Adsorbent for Arsenic(III) Removal

Synthesis of bimetallic‐oxide‐encapsulated magnetic nanoparticles is still significantly challenging and has rarely been attempted previously, due to the effects of lattice mismatch, weak chemical interactions and variances in growth rates between different components, as well as the difficulty in process control for uniform co‐deposition. In the present work, Fe‐Mn bimetallic oxide (FMBO) nanoplatelet encapsulated magnetic nanoparticles (Mag‐FeMn) are prepared by controlled engineering of the interparticle coupling of Fe₃O₄ and FMBO, with its multifunctional capabilities highlighted in terms of the potentially superior As(III) sequestration and convenient recoverability. Multiple characterization techniques are employed to examine the derived morphologies and to accurately resolve both compositionally and magnetically the hierarchical structure in detail. The synthesized magnetic composites retain highly porous structure with the main components of Fe₂O₃, FeOOH, Fe₃O₄, and Mn₃O₄. Mag‐FeMn exhibits a quite competitive high capacity for As(III) capture (56.1 mg g^–1), whereby As(III) oxidation coupled with synchronous sorption contributes to the improved performance. The unique heterostructure of FMBO encapsulation with an embedded magnetic core would be applicable to help with rational synthesis of other bimetallic oxide encapsulated magnetic nanoparticles, and definitely shows promise for the development of new nanotechnology enabled approaches for adsorption‐based water purification.     

有源介观LC电路的量子涨落

本文利用含时微扰论,研究了电源幅值较小时介观LC电路中电荷与电流的量子涨落。在确定的温度下,系统将处在混合态,进一步得到有限温度下含源介观LC电路的量子涨落。研究表明有源介观LC电路的量子涨落不仅与电路参数有关,还与时间和温度有关。     

The simplified material parameter equation for elliptical cylinder cloaks

We simplify the material parameter equation for elliptical cylinder cloaks under transverse-electric and transverse-magnetic models, respectively, and confirm these simplified equations by numerical simulations. As a result, the number of the component parameters is reduced from three to two, which simplifies the design of meta-materials and thus opens up the possibility of achieving elliptical cylinder cloaks in an easy way.     

Effect of mesoporous carbon containing binary conductive additives in lithium ion batteries on the electrochemical performance of the LiCoO2 composite cathodes

Binary conductive additives (BCA), formed by sonication of mesoporous carbon (MC) and acetylene black (AB), were used as conductive additives to improve the electrochemical performance of a LiCoO₂ composite cathode. The electrochemical performance of the LiCoO₂ composite cathode dispersed with BCA was investigated. The results showed that the electrochemical performance (including the discharge capacity, the discharge voltage and the total internal resistance) of a BCA loaded LiCoO₂ composite cathode was better than that of a cathode loaded with AB. The possible mechanism is that the MC in BCA can adsorb and retain electrolyte solution, which allows an intimate contact between the lithium ions and the cathode active material LiCoO₂ due to its large mesopore specific surface area. A simplified model was also proposed.     

The Initial Reactions of H3PO4 and NaH2PO4Supported on Silica: A Joint Experimental and Theoretical Study

利用XRD、TG、DRIFTS、31P MAS NMR和密度泛函理论研究了浸渍法制备的硅胶负载型磷酸和磷酸二氢钠催化剂,阐明了催化剂制备过程中生成的初始缩合产物和其反应机理. 光谱试验结果显示,在二氧化硅负载的磷酸上,除了聚磷酸外,还有硅磷酸盐的存在;在二氧化硅负载的磷酸二氢钠上,仅发现聚磷酸钠存在. 密度泛函模拟结果也证明,磷酸与二氧化硅表面硅羟基之间的反应在缩合反应的初始阶段比其自身的二聚反应更为有利. 但是在硅胶负载的磷酸二氢钠上,磷酸二氢钠的二聚和三聚是缩合反应初始阶段的主要反应.     

极限热环境下大功率PCB散热改进研究

通过改进太阳罩结构、改变PCB安装形式、设置隔热等方式,对大功率PCB在大空间极限热环境下的散热方式进行了优化和数值模拟。研究结果表明,根据不同发热电子元件的功率及其在PCB上的安装位置及与PCB的连接形式,采用上述措施,可以显著改善散热效果。     

All-solid-state 543 nm green laser generated by frequency doubling of a diode pumped Nd:YVO<Subscript>4</Subscript> laser at 1086 nm

An efficient and compact green laser at 543 nm is generated by intracavity frequency doubling of a continuous wave (CW) laser operation of a diode pumped Nd:YVO₄ laser at 1086 nm under the condition of suppression the higher gain transition near 1064 nm. With 10 W diode pump power and a frequency doubling crystal LBO, as high as 2.13 W of CW output power at 543 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 21.3% and the output power stability in 3 h is better than 2.27%.     

Evaluation of the acoustic nonlinearity parameter of materials with Rayleigh waves excited directly

An experimental technique for the determination of the relative acoustic nonnnearity parameter of materials with Rayleigh waves excited directly is presented. Rayleigh surface waves were directly generated in materials by the specific piezoelectric transducer fixed at the specimen＇s edge, and were measured with a laser interferometer system. After the Rayleigh wave signals were processed with FFT method, the relative acoustic nonlinearity parameter of materials was then determined from the absolute magnitudes of the fundamental and second harmonics of Rayleigh surface waves. This procedure was used to determine the acoustic non- linearity parameters of aluminum alloys 2024 and 6061. It is shown that the results comply well with those available in the literature; this method can thus be used to evaluate the acous- tic nonlinearity parameter of materials effectively. This technique can provide a practical way in the nondestructive characterization of degradation of materials and structures in the early fatigue life.