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121.
膨化方便食品的质量控制手段 总被引:1,自引:0,他引:1
根据膨化方便食品(油炸、挤压膨化食品)的加工、保藏和包装特点,分析了控制膨化方便食品质量的手段。 相似文献
122.
研究了简化应变诱发激活(SIMA)工艺条件下Mg-5.5Zn-2Gd-0.6Zr挤压态镁合金在不同等温温度(600,610和620℃)和不同等温时间条件下的微观组织演变规律。结果表明,在相同等温温度条件下,α(Mg)晶粒直径与等温时间之间符合关系式3 30d?d?Kt,粗化速率常数K随等温温度的升高而增大;实验合金的粗化机制符合Monson-Whitton等提出的改进的液膜迁移理论模型。分析发现,实验合金的纵向组织α(Mg)晶粒粗化速率大于其横向组织α(Mg)晶粒粗化速率,这是简化SIMA法工艺在制备半固态触变浆料时存在组织不均匀现象的根本原因。 相似文献
123.
为提高青霉素酰化酶的催化性能和热稳定性,在酶组装过程中添加小分子试剂对介孔泡沫硅载体表面过量的活化位点进行封闭。详细考察了小分子添加质量分数和种类对青霉素酰化酶负载率、催化活力及热稳定性的影响。实验结果得到:经精氨酸封闭的固定化酶活力提高至1.92倍;甘氨酸封闭的固定化酶5 h的50℃热稳定性提高至2.9倍,甘氨酸和谷氨酸封闭的固定化酶50℃热处理25 h仍保持87.9%和82.2%的残余活力;甘氨酸和谷氨酸封闭的固定化酶最适催化pH值向中性偏移且对pH值的耐受性增强。结果表明,在青霉素酰化酶共价组装过程中添加合适的小分子封闭能显著提高酶的催化性能和热稳定性。 相似文献
124.
Thomas O.J. Blomfeldt Richard T. Olsson Mohan Menon David Plackett Eva Johansson Mikael S. Hedenqvist 《大分子材料与工程》2010,295(9):796-801
A new way of producing rigid or semi‐rigid foams from vital wheat gluten using a freeze‐drying process is reported. Water/gluten‐based mixtures were frozen and freeze‐dried. Different foam structures were obtained by varying the mixing process and wheat gluten concentration, or by adding glycerol or bacterial cellulose nanofibers. MIP revealed that the foams had mainly an open porosity peaking at 93%. The average pore diameter ranged between 20 and 73 µm; the sample with the highest wheat gluten concentration and no plasticizer had the smallest pores. Immersion tests with limonene revealed that the foams rapidly soaked up the liquid. An especially interesting feature of the low‐wheat‐concentration foams was the “in situ” created soft‐top‐rigid‐bottom foams.
125.
126.
水榭山庄花园设计为高档别墅区,外墙采用建筑节能复合保温墙,通过样板先行、后大面积施工,明确施工工艺及标准,有效进行了施工过程中的质量控制,可为同类项目施工提供参考。 相似文献
127.
128.
Weiyuan Lin Yoshiki Hamamoto Yuta Hikima Masahiro Ohshima 《Polymer Engineering and Science》2023,63(1):44-54
Microcellular injection molding is an attractive method. However, their surface imperfections have been a major problem hindering wide industrial applications. Several methods have been proposed to improve the surface appearance of foams. In this study, we proposed a method to improve the surface appearance of polypropylene (PP) foams from the material property perspective, especially with regard to crystallization and viscosity. The basic idea of the surface improvement is to reduce the size of bubbles generated at the flow front, delay the solidification behavior of the polymer at the mold interface, squeeze the bubbles existing at the mold–polymer interface, and redissolve the bubbles into the polymer by holding pressure. Blending a low-modulus PP delays the crystallization of the polymers at the skin layer and solidification, taking enough time to squeeze the bubbles smaller. A sorbitol-based gelling agent, bis-O-([4 methylphenyl]methylene)-D-Glucitol, was used to increase the viscosity at a low strain rate to reduce the size of the bubbles generated at the flow front during the filling stage. The foam injection molding experiments demonstrated that the proposed method effectively improved the surface appearance of the foams. In particular, the surface appearance of the foams became almost equivalent to that of solid samples using low-modulus PP. 相似文献
129.
Jun Lai Feng Huang An Huang Tong Liu Xiangfang Peng Jianming Wu Lihong Geng 《Polymer Engineering and Science》2023,63(4):1082-1093
Long carbon chain thermoplastic polyamide elastomer (TPAE) with PA1212 as hard segment and polytetrahydrofuran as soft segment was synthesized successfully. Subsequently, thermoplastic polyurethane (TPU) incorporated to compensate for the high cost of TPAE and improved the foaming performance, in which a chain extender (ADR) was applied to enhance melt strength and interfacial compatibility simultaneously. The effect of ADR content on the mechanical, thermal, rheological, and foaming properties of TPAE/TPU composites were investigated in detail. It was found that the composite foams showed a more perfect cell structure, high cell density, and increased expansion ratio because of the enhanced melt strength and interfacial compatibility, when ADR was incorporated. With the increase of ADR content, the cell size and expansion ratio of the composite foams with TPU content of 30% showed a trend of first increasing and the following decreasing. The cell size reached a maximum value when the content of ADR was 2%, which was 25.81 μm. Consequently, the obtained TPAE/TPU composite foams showed an outstanding compressive modulus and resilient performance to broaden its application in footwear industry. 相似文献
130.
Zhen Yu Yifa Song Lijuan Yang Shibao Wen Yingjie Zhao Yongxian Zhao Zhenxiu Zhang 《乙烯基与添加剂工艺杂志》2023,29(5):901-908
Improving the flame retardancy and lightweight of fluorosilicone rubber (FSR) foam is important for its application in aerospace, rail transportation, petrochemical equipment, etc. In this work, ammonium polyphosphate (APP) and expandable graphite (EG) were used as synergistic flame retardants, and the lightweight FSR composite foam with flame retardancy was prepared by supercritical N2 foaming. When there were 12.5 phr APP and 7.5 phr EG, the composite foam with density of 0.254 g/cm3 showed superiority in foaming performance and flame retardancy, and the limit oxygen index was 36.4%, the UL-94 grade reached V-0, the ignition time was 12 s and the fire performance index was 0.071 s·m2/kW. In addition, the aging, oil and solvent resistance of FSR foam was not affected. This work provided data support for the production and application of the flame retardant FSR foam. 相似文献