针对目前制备壳聚糖膜无法控制厚度的问题,以壳聚糖(CS)为基体,将L-精氨酸固载到CS大分子上,制备L-精氨酸接枝壳聚糖(CS-L-Arginine,CA),并分别在保鲜膜、涤纶膜上刮膜,考察其成膜性、膜厚度、拉伸强力及抗菌性能.结果表明:以2%的冰乙...针对目前制备壳聚糖膜无法控制厚度的问题,以壳聚糖(CS)为基体,将L-精氨酸固载到CS大分子上,制备L-精氨酸接枝壳聚糖(CS-L-Arginine,CA),并分别在保鲜膜、涤纶膜上刮膜,考察其成膜性、膜厚度、拉伸强力及抗菌性能.结果表明:以2%的冰乙酸溶液为分散剂、以10 g/L山梨醇为增塑剂,CA的质量分数为5%时,以涤纶膜作为刮膜底物制备的CA膜厚度均匀为0.03 mm,拉伸强力为389 c N/cm,对Cu^(2+)和Ni^(2+)离子的去除率分别为74.53%和69.36%,优于以保鲜膜为底物的CA膜,且对大肠杆菌和金黄色葡萄球菌的抑菌率高达90.23%和93.37%.这说明CA粉末在成膜后保持其对Cu^(2+)、Ni^(2+)优良的吸附性能和对大肠杆菌、金黄色葡萄球菌高效的抗菌性.展开更多
The catalytic activity of trimethyl phosphite modified HZSM-5 zeolite and un-modified HZSM-5zeolite treated with 100% steam at 673,773,873,973 and 1073K, respectively, were investigated using heptanecracking as a prob...The catalytic activity of trimethyl phosphite modified HZSM-5 zeolite and un-modified HZSM-5zeolite treated with 100% steam at 673,773,873,973 and 1073K, respectively, were investigated using heptanecracking as a probe reaction. The results showed that the heptane conversion of both trimethyl phosphitetreated samples and un-phosphated samples decreased with an increase in treating temperature, but trimethylphosphite modified samples showed higher activity in comparison with the un-modified samples, which weresteam-treated at a higher temperature. The results were firstly elucidated by the model cluster method andcomputational quantum chemistry method. Full optimization and frequency analysis of all cluster model havebeen carried out using the Gaussian 94 software-package with the PM 3 semi-empirical method performed onsmall cluster models. The computational results showed that the dealumination of trimethyl phosphite modi-fied zeolite model cluster was more difficult than that of un-modified zeolite model cluster when they weretreated with steam while investigating the heat of reaction.展开更多
A series of symmetrical peptidomimetics （3-8） based on cysteine-modified cyclo（L-Lys-L-Lys）s were synthesized, and their gelation capability in organic solvents was dominated by fluorenylmethyloxycarbonyl （Fmoc）...A series of symmetrical peptidomimetics （3-8） based on cysteine-modified cyclo（L-Lys-L-Lys）s were synthesized, and their gelation capability in organic solvents was dominated by fluorenylmethyloxycarbonyl （Fmoc） and triphenylmethyl （Trt） protecting groups and the exchange of thiol-to-disulfide as well. The peptidomimetics holding Trt （3 and 4） showed no gel performance, while the Fmoc groups promoted 5 and 6 to give rise to thermo-reversible organogels in a number of organic solvents. The self-assembled fibrillar networks were distinctly evidenced in the organogels by transmission electron micros- copy （TEM） and scanning electron microscopy （SEM） observations. Fourier transform infrared spectroscopy （FT-IR） and fluorescence analyses revealed that the hydrogen bonding and ^-rt stacking play as major driving forces for the self-assembly of these organogelators. A 13-turn secondary structure was deduced for the organogel of 6 by virtue of X-ray diffraction, FT-IR and circular dichroism （CD） measurements, and an interdigitated bilayer structure was also presented.展开更多
文摘针对目前制备壳聚糖膜无法控制厚度的问题,以壳聚糖(CS)为基体,将L-精氨酸固载到CS大分子上,制备L-精氨酸接枝壳聚糖(CS-L-Arginine,CA),并分别在保鲜膜、涤纶膜上刮膜,考察其成膜性、膜厚度、拉伸强力及抗菌性能.结果表明:以2%的冰乙酸溶液为分散剂、以10 g/L山梨醇为增塑剂,CA的质量分数为5%时,以涤纶膜作为刮膜底物制备的CA膜厚度均匀为0.03 mm,拉伸强力为389 c N/cm,对Cu^(2+)和Ni^(2+)离子的去除率分别为74.53%和69.36%,优于以保鲜膜为底物的CA膜,且对大肠杆菌和金黄色葡萄球菌的抑菌率高达90.23%和93.37%.这说明CA粉末在成膜后保持其对Cu^(2+)、Ni^(2+)优良的吸附性能和对大肠杆菌、金黄色葡萄球菌高效的抗菌性.
文摘The catalytic activity of trimethyl phosphite modified HZSM-5 zeolite and un-modified HZSM-5zeolite treated with 100% steam at 673,773,873,973 and 1073K, respectively, were investigated using heptanecracking as a probe reaction. The results showed that the heptane conversion of both trimethyl phosphitetreated samples and un-phosphated samples decreased with an increase in treating temperature, but trimethylphosphite modified samples showed higher activity in comparison with the un-modified samples, which weresteam-treated at a higher temperature. The results were firstly elucidated by the model cluster method andcomputational quantum chemistry method. Full optimization and frequency analysis of all cluster model havebeen carried out using the Gaussian 94 software-package with the PM 3 semi-empirical method performed onsmall cluster models. The computational results showed that the dealumination of trimethyl phosphite modi-fied zeolite model cluster was more difficult than that of un-modified zeolite model cluster when they weretreated with steam while investigating the heat of reaction.
基金the National Natural Science Foundation of China (21174018)
文摘A series of symmetrical peptidomimetics （3-8） based on cysteine-modified cyclo（L-Lys-L-Lys）s were synthesized, and their gelation capability in organic solvents was dominated by fluorenylmethyloxycarbonyl （Fmoc） and triphenylmethyl （Trt） protecting groups and the exchange of thiol-to-disulfide as well. The peptidomimetics holding Trt （3 and 4） showed no gel performance, while the Fmoc groups promoted 5 and 6 to give rise to thermo-reversible organogels in a number of organic solvents. The self-assembled fibrillar networks were distinctly evidenced in the organogels by transmission electron micros- copy （TEM） and scanning electron microscopy （SEM） observations. Fourier transform infrared spectroscopy （FT-IR） and fluorescence analyses revealed that the hydrogen bonding and ^-rt stacking play as major driving forces for the self-assembly of these organogelators. A 13-turn secondary structure was deduced for the organogel of 6 by virtue of X-ray diffraction, FT-IR and circular dichroism （CD） measurements, and an interdigitated bilayer structure was also presented.
