Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
Not a member yet
40778 research outputs found
Sort by
Modulating Catalytic Activity and Stability of Atomically Precise Gold Nanoclusters as Peroxidase Mimics via Ligand Engineering
No full textMetal nanoclusters (NCs), composed of a metal core and protecting ligands, show promising potentials as enzyme mimics for producing fuels, pharmaceuticals, and valuable chemicals, etc. Herein, we explore the critical role of ligands in modulating the peroxidase mimic activity and stability of Au NCs. A series of Au15(SR)13 NCs with various thiolate ligands [SR = N-acetyl-L-cysteine (NAC), 3-mercapto-propionic acid (MPA), or 3-mercapto-2-methylpropanoic acid (MMPA)] are utilized as model catalysts. It is found that Au15(NAC)13 shows higher structural stability than Au15(MMPA)13 and Au15(MPA)13 against external stimuli (e.g., pH, oxidants, and temperature) because of the intramolecular hydrogen bonds. More importantly, detailed enzymatic kinetics data show that the catalytic activity of Au15(NAC)13 is about 4.3 and 2.7 times higher than the catalytic activity of Au15(MMPA)13 and Au15(MPA)13, respectively. Density functional theory (DFT) calculations reveal that the Au atoms on the motif of Au NCs should be the active centers, whereas the superior peroxidase mimic activity of Au15(NAC)13 should originate from the emptier orbitals of Au atoms because of the electron-withdrawing effect of acetyl amino group in NAC. This work demonstrates the ligand-engineered electronic structure and functionality of atomically precise metal NCs, which afford molecular and atomic level insights for artificial enzyme design
单价选择性阴离子交换膜的改性研究进展
No full text详细介绍了表面改性法和膜基体改性法的原理、特点及其改性效果,总结了近3年来单价选择性阴离子交换改性的研究进展并对不同改性方法进行了评价。结果表明,膜改性是一种提高单价选择性阴离子交换膜的渗透选择性、离子通量和抗污染性能的有效方法。最后分析了限制单价选择性阴离子交换膜量产的因素,并展望了单价选择性阴离子交换膜可能的量产方向
胶原的百年研究历程回顾与展望
No full text胶原作为细胞外基质的主要成分,是脊椎动物体内含量最丰富的蛋白。胶原研究历程与人们对生命本质的认识过程密不可分,从纤维学说到细胞学说确立经历了数百年的历程。近百年来,胶原的应用从制革和黏合剂等,逐渐拓展至食品、药品、化妆品、生物材料,近年来拓展至组织工程、再生医学及干细胞定向转化等。结合已有的文献报道及相关研究经验,针对胶原的研究历程、应用范围以及相关技术在胶原研究中的应用、取得的阶段性进步或成果等进行梳理。以期为胶原领域的研究人员提供胶原研究的最新动向,使其充分理解技术进步与科学研究之间的关系,同时有助于促进不同学科领域的交叉与融合
Effect of Substrate Temperature on Structure of Vacuum Evaporated Zinc-Magnesium Alloy Coating
No full textAbstract
In order to solve the problem that the poor plating ability of Galvanized ultra-high strength steel automobile sheet made by traditional continuous hot-dip galvanizing method and the problem that it is difficult to prepare high magnesium (more than 3%) content coated steel sheet by traditional continuous hot-dip galvanizing method. In this chapter, Zn-Mg coating was evaporated at substrate temperature of 50 °C, 100 °C, 150 °C and 200 °C by double source co-evaporation method, and the microstructure and adhesion of single-layer Zn Mg coating were analyzed. The results show that, with the increasing of substrate temperature, the surface grains of zinc magnesium coating have a trend of increasing gradually, but the adhesion of the coating has a trend of decreasing, among which ZnMg-100 coating has the best adhesion
3D bioprinting of dECM/Gel/QCS/nHAp hybrid scaffolds laden with mesenchymal stem cell-derived exosomes to improve angiogenesis and osteogenesis
No full textAbstract Craniofacial bone regeneration is a coupled process of angiogenesis and osteogenesis, which, associated with infection, still remains a challenge in bone defects after trauma or tumor resection. 3D tissue engineering scaffolds with multifunctional-therapeutic properties can offer many advantages for the angiogenesis and osteogenesis of infected bone defects. Hence, in the present study, a microchannel networks-enriched 3D hybrid scaffold composed of decellularized extracellular matrix (dECM), gelatin (Gel), quaterinized chitosan (QCS) and nano-hydroxyapatite (nHAp) (dGQH) was fabricated by an extrusion 3D bioprinting technology. And enlightened by the characteristics of natural bone microstructure and the demands of vascularized bone regeneration, the exosomes (Exos) isolated from human adipose derived stem cells as angiogenic and osteogenic factors were then co-loaded into the desired dGQH20 hybrid scaffold based on an electrostatic interaction. The results of the hybrid scaffolds performance characterization showed that these hybrid scaffolds exhibited an interconnected pore structure and appropriate degradability (>61% after 8 weeks of treatment), and the dGQH20 hybrid scaffold displayed the highest porosity (83.93 ± 7.38%) and mechanical properties (tensile modulus: 62.68 ± 10.29 MPa, compressive modulus: 16.22 ± 3.61 MPa) among the dGQH hybrid scaffolds. Moreover, the dGQH20 hybrid scaffold presented good antibacterial activities (against 94.90 ± 2.44% of Escherichia coli and 95.41 ± 2.65% of Staphylococcus aureus, respectively) as well as excellent hemocompatibility and biocompatibility. Furthermore, the results of applying the Exos to the dGQH20 hybrid scaffold showed that the Exo promoted the cell attachment and proliferation on the scaffold, and also showed a significant increase in osteogenesis and vascularity regeneration in the dGQH@Exo scaffolds in vitro and in vivo. Overall, this novel dECM/Gel/QCS/nHAp hybrid scaffold laden with Exo has a considerable potential application in reservation of craniofacial bone defects.</p
Dynamic behaviors of bubble formation on submerged micro-capillary under constant flow conditions
No full textBubble column offers various advantages compared to other devices in the chemical process industry, which was used as a fine particulate and sulfuric acid mist control device. Bubble formation behaviors, including volume, diameter and velocity, were systematically investigated in the single submerged micro-capillary test bed under constant flow conditions by using the high-speed optical camera in this paper. Besides, force model of the bubble forming process was established based on the experimental results. It was found that the formed bubble turned to be elliptical and bubble shape was independent of the gas flow rate under the conditions of this study. In addition, bubble velocity was found quickly reached the highest level, then decreased, and eventually tended to be stable (0.02-0.1 m/s). By analyzing the bubble forces, it was found that pressure force FP, surface tension force FS and buoyancy force FB played different roles in different bubble formation process. These results can provide detailed parameters for the modeling of bubble formation process under the test conditions
Molecular-Layer-Deposited Zincone Films Induce the Formation of LiF-Rich Interphase for Lithium Metal Anodes
No full textLithium metal anodes suffer from low Coulombic efficiency and dendritic growth owing to an unstable solid electrolyte interphase (SEI), which limit the practical applications of lithium metal anodes. Here, zincone (ZnHQ) is conformally fabricated on 3D copper nanowires (CuNWs) via a molecular layer deposition (MLD) technology. Upon polarization, the terminal oxygen of ZnHQ serves as a strong nucleophilic agent to attack Li bis(trifluoromethanesulfonyl)imide, yielding a LiF-rich SEI. This SEI facilitates the Li transport, shuts off the electron conduction, and inhibits the growth of lithium dendrites. In addition, the zinc atoms of ZnHQ induce favorable Li deposition owing to their lithiophilicity. These advantages enabled by MLD make the ZnHQ-modified CuNW (CuNW@ZnHQ) an ideal Li metal anode, which demonstrates excellent cyclability. A symmetrical cell of CuNW@ZnHQ shows high cycling stability for more than 7000 h at the current density of 1 mA cm(-2). When pairing with a Ni/Co/Mn ternary oxide cathode (NCM523), the resultant CuNW@ZnHQ||NCM full cell is cycled for 1000 cycles with a 90% capacity retention at an areal capacity of 3.2 mAh cm(-2). The MLD technology brings new opportunities for next-generation high-energy Li metal batteries
Depolymerization of polyethylene terephthalate with glycol under comparatively mild conditions
No full textThe depolymerization of polyethylene terephthalate (PET) can proceed by using ethylene glycol (EG) as an alcoholysis solvent. However, high reaction temperature (>= 180 degrees C) of glycolysis process requires high energy consumption, and unfortunately results in yellowing of monomer product, i.e., bis(2-hydroxyethyl) terephthalate (BHET), limiting the production of high-quality and colorless recycled PET (rPET). To address this problem, a strategy involving acetonitrile as cosolvent was applied to decrease glycolysis temperature to 90 degrees C or even lower, and solvents as well as catalyst can be recycled and reused. The glycolysis of PET is hard to proceed at 90 degrees C. However, the swelling effect of acetonitrile caused cracks and defects on the surface of PET, which promoted the depolymerization of PET and led to an S-shaped reaction curve. Besides, adding acetonitrile could significantly accelerate the degradation of oligomers into BHET. Under the optimal reaction conditions, the conversion of PET and yield of BHET could reach 96% and 90%, respectively