Ultraviolet‐C Light Sanitization of English Cucumber (Cucumis sativus) Packaged in Polyethylene Film

Food safety is becoming an increasing concern in the United States. This study investigated the effects of ultraviolet‐C (UV‐C) light as a postpackaging bactericidal treatment on the quality of English cucumber packaged in polyethylene (PE) film. Escherichia coli k‐12 was used as a surrogate microbe. The microbial growth and physical properties of packaged cucumbers were analyzed during a 28‐d storage period at 5 °C. Inoculating packaged cucumbers treated at 23 °C for 6 min with UV‐C (560 mJ/cm²) resulted in a 1.60 log CFU/g reduction. However, this treatment had no significant effect (P > 0.05) on the water vapor transmission rate or oxygen transmission rate of the PE film. Results show that UV‐C light treatment delayed the loss of firmness and yellowing of English cucumber up to 28 d at 5 °C. In addition, UV‐C light treatment extended the shelf life of treated cucumber 1 wk longer compared to untreated cucumbers. Electron microscopy images indicate that UV‐C light treatment influences the morphology of the E. coli k‐12 cells. Findings demonstrate that treating cucumbers with UV‐C light following packaging in PE film can reduce bacterial populations significantly and delay quality loss. This technology may also be effective for other similarly packaged fresh fruits and vegetables.     

新型棉/氨弹力织物的染整工艺研究

系统研究了染整加工中各工艺因素对棉/氨弹力织物各项性能的影响.研究表明,棉/氨弹力织物高温碱性条件下,损伤较为严重;双氧水漂白后织物的强力和弹性损伤较次氯酸钠漂白小;丝光碱用量以180g/L为宜;热定形以温度180℃,时间30s为宜.对含氨纶较少的棉/氨弹力织物可选择活性染料染色,染色后各项牢度较好,弹性回复率较高.     

翡翠中蜡质物和高分子聚合物充填处理尺度的判别

在翡翠的漂白、酸碱蚀、蜡质物和高分子聚合物注入等项实验研究的基础上,利用傅立叶变换红外光谱仪,重点对蜡质物和高分子聚合物充填处理翡翠的红外吸收光谱进行表征.结果表明,利用2 800～3 000 cm-1范围内由蜡质物和高分子聚合物(CH2和CH3官能团)致红外吸收谱带的相对吸收比(Ra)和其半峰宽面积(Sa),可以对翡翠的优化与处理尺度进行判定,即:1/4＜Ra≤2/4,Sa≤15(无需标识);2/4＜Ra≤3/4,15＜Sa≤30(为"优化");3/4＜Ra≤4/4,30＜Sa(为"处理").对翡翠的漂白、漂白充填处理和酸碱蚀充填处理的本质与属性予以了剖析.     

汽车滤清器非织造过滤材料的开发

根据汽车滤清器的使用要求试制开发了复合型非织造空气过滤材料。通过对原料、工艺及不同过滤材料的对比进行了分析和探讨。试验证实了复合型非织造过滤材料达到了汽车滤清器的要求并满足了国内外客户的愿望。     

冲裁模具寿命的研究

在工厂实践的基础上，从冲裁零件设计、冲裁工艺过程安排、冲裁模具设计和模具零件材料的选择与热处理等方面提出了延长冲裁模具寿命的方法。     

Migration of bisphenol A from polycarbonate baby bottles under real use conditions

Migration of the potential endocrine disrupter, bisphenol A (BPA), from 31 polycarbonate (PC) baby bottles into aqueous food simulants was studied under real repetitive use, using a sensitive and fully validated liquid chromatographic method with fluorescence detection. Confirmation of the presence of BPA was performed by liquid chromatography–mass spectrometry (LC–MS). The effects of cleaning in a dishwasher or with a brush, sterilization with boiling water and the temperature of migration were examined. It was shown that temperature was the crucial factor for the migration of BPA from the plastic bottles to water. All samples released BPA in the concentration range 2.4–14.3 µg kg^?1 when filled with boiled water and left at ambient temperature for 45 min. The decrease of BPA release in the sterilization water and in the food simulant over 12 cycles of use indicated that the hypothesis of polymer degradation in water is dubious. Estimated infantile dietary exposure, regarding the use of PC baby bottles, ranged between 0.2 and 2.2 µg kg^?1 bw day^?1, which is below the Tolerable Daily Intake of 50 µg kg^?1 bw recently established by EFSA.     

两亲聚合物加脂剂新进展

综述了两亲聚合物加脂剂的合成方法和应用现状,并预测了其今后的发展趋势。     

含氧化叔胺侧基的水溶性酚醛树脂的制备与性能

为了得到一种具有热致亲和性变化的酚醛树脂,应用于热敏成像体系中,制备和表征了一种新型含氧化叔胺侧基的水溶性酚醛树脂。首先,二甲胺与甲基丙烯酸甲酯通过加成反应,随后水解制得3-二甲胺基丙酸。其次,3-二甲胺基丙酸通过双氧水氧化,生成氮氧化3-二甲胺基丙酸。再次,酚醛环氧树脂与氮氧化3-二甲胺基丙酸反应得到水溶性改性酚醛树脂。对制备的树脂的热行为和热致溶解性变化性能进行了研究。研究发现,改性酚醛树脂在120℃下加热10min仍然能在水中溶解,其溶解性几乎没有改变。但是,当温度加热到140℃时,该树脂变得完全不溶于水。这种改性酚醛树脂具有良好的成膜性能,涂布后可形成均匀的膜并能很强地附着于版基上。     

天丝/锦纶复合经弹面料的开发

采用天丝和锦纶、氨纶复合开发了经向弹力面料,对织物的设计与生产加工工艺要点进行了分析探讨,合理和组合使用天丝纤维可发挥其光泽好、手感柔软、尺寸稳定、强力高、吸湿性好的优点,开发出有特色的弹力织物。     

思茅松松节油标准样品的定值研究

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U_A=0.23 %,扩展不确定度U_0.95=0.45 %; β-蒎烯含量X_标=17.80 %,标准不确定度U_A=0.08 %,扩展不确定度U_0.95=0.16 %; β-水芹烯含量为X_标=3.50 %,标准不确定度U_A=0.08 %,扩展不确定度U_0.95=0.16 %。