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黑曲霉液体发酵制备 β- 葡萄糖苷酶的研究 总被引:5,自引:0,他引:5
研究了培养条件对黑曲霉液体发酵制备β-葡萄糖苷酶的影响及β-葡萄糖苷酶的表观酶学性质。麸皮是黑曲霉β-葡萄糖苷酶的较适诱导物。黑曲霉NL02以 40 g/L 麸皮为碳源,在 250 mL 三角瓶中装液 40 mL,接种量 8%,初始pH值5.5, 30℃、 170 r/min 下培养 10 d,β-葡萄糖苷酶活力为 19.12 IU/mL。β-葡萄糖苷酶最适温度为 65℃,40℃ 时稳定性较好;最适pH值为4.8,在pH值3.0~5.0之间稳定性较好。 相似文献
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不同品种桂花挥发油成分的GC-MS分析 总被引:3,自引:0,他引:3
采用水蒸气蒸馏法提取了江西地区金桂、银桂和四季桂3种桂花的挥发油,通过气相色谱-质谱联用法分析鉴定了3种桂花挥发油的化学成分及其含量。金桂挥发油中的主要成分是氧化芳樟醇、香叶醇、 α-紫罗兰酮、β-紫罗兰酮、二氢猕猴桃内酯和邻苯二甲酸二丁酯等;主要香气成分为香叶醇、 α-紫罗兰酮、 β-紫罗兰酮、丁位癸内酯和芳樟醇及其氧化物。银桂挥发油的主要成分是氧化芳樟醇、环氧芳樟醇、丁位癸内酯、 β-紫罗兰醇、 β-紫罗兰酮、二氢猕猴桃内酯、邻苯二甲酸二异丁酯和邻苯二甲酸二丁酯等;主要香气成分为β-紫罗兰醇、 β-紫罗兰酮、丁位癸内酯和氧化芳樟醇。四季桂挥发油的主要成分是香叶醇、茶香螺烷、 β-紫罗兰醇、 4-(2,6,6-三甲基-环己-1-己烯)-丁烷-2-醇、邻苯二甲酸二丁酯和丁位癸内酯等;主要香气成分为β-紫罗兰醇、香叶醇和茶香螺烷。 相似文献
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松节油标准样品的制备及特征组分研究 总被引:5,自引:2,他引:5
对比研究了溶剂法和水蒸气蒸馏法制备马尾松、湿地松和思茅松松节油的工艺,使用水蒸气蒸馏法制得的3种松节油样品均符合国家标准《脂松节油》GB/T 12901-2006的质量指标要求。GC和GC-MS分析结果显示, 3种松节油样品的主要特征组分有α-蒎烯、β-蒎烯、苧烯、β-水芹烯和长叶烯、石竹烯等,而且含量差异比较明显。主要成分α-蒎烯与β-蒎烯相对含量之比分别为马尾松松节油8.5、湿地松松节油2.0和思茅松松节油4.0,该比值具有非常明显的差异性,其比值的大小有可能作为松树树种鉴别的一项重要判断依据。 相似文献
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以β-蒎烯为原料,在阴离子交换树脂负载ZnCl2催化作用下,与多聚甲醛反应合成诺卜醇。研究了氯化锌的负载量、原料配比、反应温度和反应时间对诺卜醇产率的影响及催化剂的重复使用性能。在β-蒎烯与甲醛摩尔比3:1,反应温度80℃,反应时间4 h条件下,诺卜醇产率达到62.4%。催化剂可重复使用。 相似文献
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天然产物白果会因干燥方式的不同,而使得干燥白果粉性能有所差别。本研究分别采用喷雾干燥(SP)与真空冷冻干燥(FD)对白果浆进行干燥处理。然后对两种干燥白果粉的性能(含水量、颗粒度、色泽、蛋白质质量分数)进行对比来比较各自的优越性。喷雾干燥采用参数:风量120 m3/h,进料浓度8%(质量分数),进气温度205℃,出气温度100℃,雾化器转速32000 r/min。真空冷冻干燥先在-40℃下预冻4h后,再在真空度300 Pa下-50℃低温干燥48 h。结果发现含水量SP相似文献
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研究了湿地松松节油标准样品的制备和稳定性、均匀性及其定值方法。湿地松松节油制备采用水蒸气蒸馏法,含量分析采用气相色谱面积归一化法。制备得到松节油标准样品在36个月内保持稳定,通过了均匀性检验。多实验室联合定值结果为:α-蒎烯含量X标=62.41%,标准不确定度UA=0.15%,扩展不确定度U0.95=0.30%;β-蒎烯含量X'标=31.66%,标准不确定度U'A=0.09%,扩展不确定度U'0.95=0.18%;β-水芹烯含量X″标=3.33%,标准不确定度U″A=0.05%,扩展不确定度U″0.95=0.10%。 相似文献
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研究了作为云南省主要采脂树种的思茅松松节油标准样品的制备和稳定性、均匀性及其定值方法。思茅松松节油制备采用水蒸气蒸馏法,含量分析采用气相色谱面积归一化法。制备得到的松节油标准样品在36个月内保持稳定,通过了均匀性检验。多实验室联合定值结果为:α-蒎烯含量X标=75.30 %,标准不确定度UA=0.23 %,扩展不确定度U0.95=0.45 %; β-蒎烯含量X标=17.80 %,标准不确定度UA=0.08 %,扩展不确定度U0.95=0.16 %; β-水芹烯含量为X标=3.50 %,标准不确定度UA=0.08 %,扩展不确定度U0.95=0.16 %。 相似文献
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以水热法自制的纳米氧化锆为原料,用油酸对其进行表面改性。考查了改性温度、油酸用量对改性粉体的分散性的影响。用TEM、SEM对改性粉体进行表征。结果表明,改性后氧化锆从亲水性明显转变为亲油性,在弱极性溶剂中分散效果良好,改性效果明显。 相似文献
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纳米氧化锌/PE复合薄膜性能研究 总被引:1,自引:0,他引:1
以硅烷偶联剂为改性剂对纳米ZnO粉体进行表面改性;采用母粒法将改性后的粉体与PE树脂混合、吹膜,并对其分散的稳定性及抗紫外性能进行了初步的探讨。结果表明:经硅烷偶联剂改性后的纳米氧化锌具有良好的稳定性和良好的抗紫外性能。 相似文献
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Yexian Sun Yifan Niu Ting Liu Jiaxiang Liu 《International Journal of Applied Ceramic Technology》2020,17(6):2690-2696
A slurry with high dispersibility is crucial for slip casting technology. The weakly acidic SiC powder with high dispersibility was prepared with polyacrylic acid pretreated by the sodium hydroxide (adjusted pH = 5). The pretreated polyacrylic acid can be effectively adsorbed on the surface of SiC powder, and its utilization efficiency (37%) was better than the unpretreated one (21%). The modified SiC powder with pH = 6 was obtained by polyacrylic acid modification, and the maximum solid content was 61.2 Vol%. The optimum of the pretreated polyacrylic acid addition amount was 1 wt% based on Zeta potential, solid content, and viscosity analysis data. Compared with the unmodified SiC, the Zeta potential absolute value of the modified (−63 mV) was higher due to a large amount of anionic modifier adsorbed on particle surfaces. The modified SiC slurry was more stable because the modification increases the electrostatic repulsion among the SiC molecules. 相似文献
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采用设计合成的含氟大分子表面改性剂,对纳米S i3N4粉体进行了表面包覆改性处理。应用TEM,FTIR,NMR,TGA等对含氟大分子表面改性剂和表面改性前后的纳米S i3N4粉体进行了表征和分析比较。结果表明,包覆在纳米S i3N4粉体表面的含氟大分子表面改性剂,与其发生了化学键合,有效地阻止了纳米S i3N4粉体的团聚。当含氟大分子表面改性剂用量为7%时,包覆改性后的纳米S i3N4粉体的粒径较小,为64.5 nm,分布最窄,分散性最好。 相似文献
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水基改性碳化硅陶瓷料浆流变性的研究 总被引:7,自引:0,他引:7
用有机硅偶联剂处理SiC粉体,在适合的上,经聚合反应再将有机的单体接枝于SiC颗粒表面上,在SiC颗粒表面上形成聚电解质包覆层,以改善SiC粒子在水介质中的分散性质。同时研究了改性SiC粉在水介质中的稳定条件,荷电性及在高固体含量下,用改性SiC粉所制备的陶瓷料浆的流变性。研究结果表明:改性后碳化硅粉在水中的分散稳定性能大大优于未改性碳化硅粉,所制备料浆体系的固体含量,分散稳定性能,粘度等参数有满足注浆成型工艺的要求。 相似文献
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《Ceramics International》2022,48(10):14192-14200
In this study, mold powder slurries with high solid loading and low viscosity were prepared during the ball-milling process for improving the homogeneity and mechanical properties of granules after spray-drying. The effect of ball-milling parameters, such as solid loading, binder/dispersant content, and ball-milling time, on the flowability, dispersibility, stability, and rheological behavior of mold powder slurries was systematically investigated by rheology observation and sedimentation tests. As these parameters varied, the slurry exhibited the shear-thinning behavior of a non-Newtonian fluid with a shear rate range of 0–50 s?1, which was adequately described by the Herschel-Bulkley model. The optimal parameters that optimized the flowability, dispersibility, and stability of the slurry, along with its rheological behavior, were chosen as follows: solid loading, 60 wt%; modified sodium carboxymethyl cellulose binder content, 1.0 wt%; sodium tripolyphosphate dispersant content, 0.5 wt%; ball-milling time, 60 min. 相似文献
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Meiling Wan Shuifeng Liu Da Huang Yang Qu Yang Hu Qisheng Su Wenxu Zheng Xianming Dong Hongwu Zhang Yen Wei Wuyi Zhou 《应用聚合物科学杂志》2021,138(13):50114
Polylactic acid (PLA) has become a popular polymer material due to its superior biocompatibility. At present, there are a few relevant research on heterogeneous bone powder. Besides, the poor dispersibility and adhesivity of inorganic particles in the organic phase remains a problem. In this study, the pork bone powders were modified with N-butanol to improve its dispersibility and compatibility in the PLA matrix. In addition, polybutylene succinate-co-terephthalates (PBSA) was applied as a flexibilizer to further reinforce the mechanical properties of materials. The composite filaments with a diameter of 1.75 ± 0.05 mm containing 10 wt% of modified bone powder, 10 wt% PBSA and 80 wt% PLA were prepared by a melt blending method. The obtained results showed that modified particles were uniformly dispersed within the PLA matrix and improved the mechanical properties of the composite filaments with a tensile strength of 48.5 ± 0.2 MPa and a bending strength of 79.1 ± 0.1 MPa and a notch impact strength of 15.8 ± 0.3 kJ/m2. And the prepared composite materials contained low cytotoxicity, high biocompatibility and printability, which verified the feasibility of it in 3D printing personalized bone repair applications. This provides a theoretical basis for further research on the effect of bone repair in vivo. Therefore, the composite material will have potential applications such as making customized bones and bone scaffolds by three dimensional printing technology. 相似文献