水分对PET聚酯切片流变性能测试的影响

利用毛细管流变仪对不同水分聚酯熔体的流变性能进行了对比研究,讨论储料装置对干燥后聚酯切片吸水性的影响,以及水分对表观粘度、非牛顿指数及粘流活化能的影响。结果表明:由于发生了水解反应,在相同温度下,聚酯熔体的表观粘度随着水分的增加而降低,非牛顿指数随着水分的增加而增大,粘流活化能随着水分的增加而增大。     

蒸煮助剂对低用碱量硫酸盐法预处理毛竹竹屑的影响

毛竹竹屑经10%低用碱量 (以Na₂O计)、20%硫化度、160 ℃下保温1 h预处理,木质素脱除率达到62.35%,预处理物料酶水解48 h葡萄糖和木糖得率分别为56.04%和53.47%。研究了硼氢化钠、三聚磷酸钠、2-蒽醌磺酸钠3种蒸煮助剂对毛竹竹屑10%用碱量硫酸盐预处理的成分以及糖化效果影响,其中2-蒽醌磺酸钠影响最大。在10%用碱量和20%硫化度的预处理液中添加0.15%的2-蒽醌磺酸时,160 ℃下保温1 h的葡聚糖回收率和木质素脱除率分别为94.93%和68.55%,与空白对比分别提高5.45%和9.94%;预处理物料酶解48 h葡萄糖和木糖得率分别为62.88%和58.97%,与空白对比分别提高12.21%和10.29%。     

聚乙二醇型含硼表面活性剂的合成

含硼特种表面活性剂具有碳氢表面活性剂无法替代的长处,具有广阔的应用前景。因此,合成含硼表面活性剂意义重大。本论文采用聚乙二醇、三乙醇胺、硼酸为原料,应用潜溶剂法（以甲苯为溶剂,通过回流带出酯化反应所生成的水）制备了含硼表面活性剂。设计正交实验确定最佳的酯化条件。实验结果表明,最佳的酯化条件为：温度（90±2）℃,硼酸、三乙醇胺、PEG（400）的摩尔比为2：1：2。最佳酯化条件下合成的聚乙二醇型三乙醇酰胺硼酸酯表面活性剂的电导率为0．36mS·cm^-1,表面张力为67．00mN·m^-1,pH值为8～9,水溶液为均一透明溶液。所合成的硼酸酯表面活性剂可以很好地应用于金属切削加工液中。     

吗啉副产物的开发利用

以吗啉工业生产中的副产物为原料,采用加压水解法,经分离后,可得到吗啉及混合醇。在210℃,2．0MPa下,水与副产物的质量比为1：1,采用氢氧化钠为催化剂,用量为副产物的1．5％,反应时间为4小时,吗啉的收率可达35％,混合醇的收率可达42％。混合醇可替代乙二醇作为防冻液的主要原料,60％的混合醇水溶液凝固点能达到-40℃以下。     

有机相中壳聚糖-海藻酸固定化脂酶的特性

研究了壳聚糖 海藻酸固定化脂酶在有机相反应中的稳定性与活性。考察了凝胶时间、壳聚糖浓度及壳聚糖分子质量对固定化脂酶包埋率与活性的影响 ,确定了适宜 pH值与批反应时间。同时讨论了溶剂极性和操作时间对固定化酶稳定性的影响。测定了固定化脂酶水解橄榄油反应的动力学参数。结果表明 ,壳聚糖 海藻酸聚电解质膜可提高固定化酶的包埋率与稳定性     

Optimization of Enzymatic Production of Oligopeptides from Apricot Almonds Meal with Neutrase and N120P

Neutrase 0.8L and N120P proteases were used for oligopeptide production from apricot almonds meal, and response surface design was carried out to optimize the effect of hydrolysis conditions on hydrolysis degree (DH) and oligopeptide yield rate. Four independent variables were used to optimize the hydrolysis process: hydrolysis temperature (X(1)), enzyme-to substrate ratio (E/S) (X(2)), substrate concentration (X(3)) and reaction time (X(4)). Statistical analysis indicated that the four variables, quadratic terms of X(1), X(3), and X(4), and the interaction terms with X(1) had a significant (p < 0.05) effect on DH. The yield rate was also significantly affected by the four variables and quadratic terms of X(1), X(2) and X(4). Two mathematical models with high determination coefficient were obtained and could be employed to optimize protein hydrolysis. The optimal hydrolysis conditions were determined as follows: hydrolysis temperature 52.5 °C; enzyme-to-substrate ratio (E/S) 7200 U/g; substrate concentration 2%; reaction time 173 min. The initial pH 6.5 and Neutrase-to-N120P dosage ratio 2:1 were fixed in this study according to the preliminary research. Under these conditions, the experimental DH and yield rate were 34.10 ± 5.25% and 72.42 ± 2.27%, respectively.     

梳形聚合物comb-1的合成

采用水溶液聚合的方法合成了二元共聚物——梳形聚合物,并通过正交试验确定了合成特性粘数较高的梳形聚合物最优试验条件:单体总浓度为20%,单体B含量为20%,引发剂浓度为0.2%,反应温度为50℃,pH值等于9。在最优条件下合成的梳形聚合物再进行了水解,并确定了最佳水解条件:水解剂质量分数为8%的NaOH,水解温度为60℃,水解时间3h。最优试验条件下合成的梳形聚合物在最佳条件下进行水解,进而获得梳形聚合物comb-1。     

Development and demonstration of a deployable apparatus for generating hydrogen from the hydrolysis of aluminum via sodium hydroxide

Emergency and backup power is often enabled through the use of petrochemical based fuels and combustion-based generator systems, and while reliable, these backup power systems fail when petrochemical supplies are disrupted due to refinery, oil outages, or transportation delays. Fuel cells in some cases can serve as a backup to these traditional generators, but they also are fuel-limited to supplies of available energy sources. Recent work conducted in our laboratories focused on the development of a “backup” emergency hydrogen generation system that could be employed when existing energy stockpiles have failed or depleted. Specifically, aluminum metal can be used to generate hydrogen for fuel cells via hydrolysis with sodium hydroxide. In this paper, we summarize the engineering work to produce a deployable aluminum to hydrogen generator which is capable of producing 3.75 kg of hydrogen per day from scrap aluminum feedstocks. The generator was built upon an aircraft deployable pallet, allowing for hydrogen to be generated remotely in cases of power and fuel outages.     

Improvement of the Characteristics of Steamed Bread by Supplementation of Recombinant alpha-L-arabinofuranosidase Containing xylan-binding domain

Current study investigated the potential to increase the activity of α-L-arabinofuranosidase (TmAra) from Thermotoga marotima on insoluble arabinoxylan (IAX) through fusion to a family 6 xylan-binding domain (CtXBD6) from Clostridium thermocellum. CtXBD6 was fused to the carboxyl terminus of TmAra, and active forms of both TmAra and TmAraCtXBD6 were produced in E. coli and purified to homogeneity for biochemical characterization. TmAraCtXBD6 had similar temperature and pH profiles to TmAra with a decrease in the thermostability and pH stability at pH 7.0–8.2. It exhibited stronger IAX-binding and hydrolytic activity than TmAra. TmAra and TmAraCtXBD6-treated IAX were added to wheat flour to investigate the rheological and textural properties of the finished product. IAX alone had significant increase in dough development time (DDT) and dough stability (DS) and decrease in the softening degree (SD), crumb firmness (CF) and specific volume (SV). On adding TmAra and TmAraCtXBD6 to treat IAX texture, SV and DS improved but decreased DDT, SD, and CF. TmAraCtXBD6 reduced CF and increased SV, and had higher springiness, cohesiveness, and crumb chewiness than TmAra. These results demonstrated that the fusion of CtXBD6 into arabinofuranosidase enables the increase in catalytic performance on insoluble AX substrates, which can be used as more efficient biocatalysts that can improve the quality of AX-rich products.     

废弃白酒糟酸水解工艺的优化

以废弃白酒糟为研究对象,利用正交实验考察了混和酸浓度、时间和温度对酒糟酸水解效果的影响,以木糖浓度和还原糖浓度为评价指标优化工艺条件,并探索最佳的超声波预处理条件。结果表明,在常温条件下,以500W功率、超声波预处理酒糟10min时酸水解效果更佳。最优的酸水解条件为混合酸浓度为2.5%、水解时间为2.5h,温度为120℃。该条件下,木糖浓度和还原糖浓度达到651.62μg/mL和11.85mg/mL。