摘要：UV irradiation hydrogen peroxide （H202） system is used as an effective, easy and low-cost combined depolymerization technique to produce oligosaccharides from chitosan. UV-Vis spectroscopic studies explained that with increasing treatment time, the absorption of the depolymerized chitosan solution has increased, indicating the increase in the carbonyl and amino groups in their structure. Fourier transform infrared spectroscopy and nuclear magnetic resonance （1H NMR） analysis showed that the 1,4-β-D-glucoside linkages of chitosan are degraded without important changes in chemical structure of decomposed samples. X-ray diffraction patterns verified the polymerization of chitosan to produce oligomers, changing in structure from crystalline to amorphous. Viscosity-average molecular weight measurements of fragmented chitosan samples and MarkHouwink equation are used to demonstrate the efficiency of this depolymerization method. Finally, the obtained results ascertained that this combined method could produce water soluble chitosan with significant efficiency and no essential change in its chemical *** irradiation hydrogen peroxide （H202） system is used as an effective, easy and low-cost combined depolymerization technique to produce oligosaccharides from chitosan. UV-Vis spectroscopic studies explained that with increasing treatment time, the absorption of the depolymerized chitosan solution has increased, indicating the increase in the carbonyl and amino groups in their structure. Fourier transform infrared spectroscopy and nuclear magnetic resonance （1H NMR） analysis showed that the 1,4-β-D-glucoside linkages of chitosan are degraded without important changes in chemical structure of decomposed samples. X-ray diffraction patterns verified the polymerization of chitosan to produce oligomers, changing in structure from crystalline to amorphous. Viscosity-average molecular weight measurements of fragmented chitosan samples and MarkHouwink equation are used to dem

摘要：The development of natural biomaterials applied for hard tissue repair and regeneration is of great importance,especially in societies with a large elderly ***-assembled peptide hydrogels are a new generation of biomaterials that provide excellent biocompatibility,tunable mechanical stability,injectability,trigger capability,lack of immunogenic reactions,and the ability to load cells and active pharmaceutical agents for tissue ***-based hydrogels are ideal templates for the deposition of hydroxyapatite crystals,which can mimic the extracellular ***,peptide-based hydrogels enhance hard tissue repair and regeneration compared to conventional *** review presents three major self-assembled peptide hydrogels with potential application for bone and dental tissue regeneration,including ionic self-complementary peptides,amphiphilic(surfactant-like)peptides,and triple-helix(collagen-like)*** attention is given to the main bioactive peptides,the role and importance of self-assembled peptide hydrogels,and a brief overview on molecular simulation of self-assembled peptide hydrogels applied for bone and dental tissue engineering and regeneration.

摘要：在赛车运动开始后不久,工程人员就意识到提高汽车转弯速度的方法之一是使汽车与路面产生更大的摩擦力.在早期进行的获取汽车与路面之间更大摩擦力的众多尝试中,较有趣的一种是采用双后轮行驶.然而,最有代表性的解决办法是采用胎面更宽,即断面宽度更大的轮胎.

摘要：Polyurethane elastomers with covalent adaptable networks(PU-CANs)based on the dynamic urethane bond have attracted remarkable attention owing to their reprocessability,adaptability,and ***,it is still a formidable challenge to achieve excellent dynamics at low temperatures since the urethane bond energy is usually ***,a fluorinated phenolic polyurethane(FPPU)elastomer with CANs based on phenol±carbamate bonds was successfully designed and ***,the effects of fluorine atoms on the mechanical properties,thermal stability,reprocessability,and self-healability,surface free energy,and hydrophobicity of the prepared elastomers were systematically *** FPPU elastomer showed notch-insensitivity,remarkable self-healable efficiency(98%),low dynamic dissociation temperature(60℃),excellent reprocessability,and low surface energy(62 MJ m^(-2))compared with non-fluorinated counterpart phenolic polyurethane elastomer(APPU).Based on the above-mentioned features,FPPU was selected as an elastic substrate to assemble into a triboelectric nanogenerator(TENG)to harvest energy from natural *** TENG exhibited an excellent electrical output performance with a peak open-circuit voltage of 103 V,a peak short-circuit current of 4.7μA and a peak short-circuit charge of 43 *** addition,the TENG possessed high selfcleaning and reprocessing ***,a stretchable and self-healing composite conductor based on FPPU was fabricated for flexible electronic devices.