Effect of microwave heating time on the gel properties of chicken myofibrillar proteins and their formation mechanism

The present work was conducted to illustrate the mechanism of gel formation of myofibrillar proteins (MPs) under different microwave heating times. The results showed that the denaturation enthalpy (ΔH) of the MPs significantly decreased when the heating time increased from 3 to 9 s and then completely disappeared as the heating time progressed, indicating that the MPs gradually denatured and subsequently aggregated with increasing heating time, which was further verified by the changes in the secondary structure, electrophoretic bands, and gel properties (e.g., water holding capacity and textural profiles) of the MPs. Microstructural images indicated that the MP gel formed under 12 s had the most compact network, indicating that extended microwave heating time could induce quality deterioration of MP gels. Moreover, the hydrophobic forces, electrostatic forces, and disulphide bonds of the MPs gradually intensified with increasing microwave heating time, suggesting that both non-covalent and covalent bonds could promote molecular denaturation and subsequent aggregation of MPs. In addition, correlation analysis revealed that the changes in the molecular conformation of MPs induced by different microwave heating times could effectively regulate the formation of MP gels and their related properties.     

Association of solid fuel use with risk of stunting in children living in China

Stunting adversely affects physical and mental outcomes of children. It has not been examined whether household air pollution from solid fuel combustion is a risk factor for stunting in children. In a total of 41,439 children aged 6-17 across China, height was measured using a unified protocol. Multivariable linear regression models and logistic regression models were used to assess the associations of solid fuel use for cooking/heating with stunting in children. Adjusted for covariates, cooking/heating with solid fuel was significantly associated with a lower z-score for height for age and sex (β = −0.21 [−0.32 to −0.09] and −0.17 [−0.31 to −0.03], respectively) and an increased risk of stunting with an estimated ORs of 1.34 [1.07~1.68] and 1.37 [1.02~1.83], respectively. The risk of stunting associated with solid fuel use was statistically significant in high-age children. And the effect was greater on girls than on boys, though the difference was not statistically significant. Our study suggested that Chinese children living in households using solid fuel had a significantly higher risk of stunting than those living in households using cleaner fuel.     

Structures and properties of chicken myofibrillar protein gel induced by microwave heating

Structures and properties of myofibrillar protein gel prepared at different power (300–800 W) were evaluated. Amino acid analysis demonstrated that changes in microwave power did not alter primary structure of gel. However, an increase in microwave power could change higher structures of gel. As microwave power increased, α-helix content decreased and β-sheet content increased. Increased microwave power probably facilitated protein to unfold and expose the internal groups, causing surface hydrophobicity and the formation of disulphide bonds were enhanced, which indicated changes in tertiary and quaternary structures of protein. At 500 W, gel had the best ultrastructure where surface morphology, springiness and water holding capacity reached the optimum. Our findings suggested that microwave at an appropriate power (500 W) could change higher structures of myofibrillar protein gel to achieve desired processing and quality protein gel characteristics.     

基于热负荷自动调节的延迟焦化加热炉三点注汽量智能优化

针对国内某炼油厂延迟焦化加热炉三点注汽问题，采用热负荷自动调节的算法进行了研究。运用该模型方法，分析了三点注汽量对加热炉热负荷和炉管结焦系数的影响，发现三点注汽量的改变均会对热负荷和炉管结焦系数产生影响，主要表现为提高注汽量将会提高热负荷，同时降低结焦系数；第1点注汽量和第2点注汽量对热负荷和结焦系数的影响较强，第3点注汽量对热负荷和结焦系数的影响较弱。在实际操作中，加热炉中的结焦程度既不能太强也不能太弱，合适的结焦系数能够保证正常开工周期里炉管不结焦，也能保证瓦斯、注汽量等参数的合理分配。通过对热负荷、注汽量的智能分配，可得到不同原料油加工负荷条件下更加合理的装置运行方案。     

碳基采暖电热材料研究进展

近几年,由于节能与环保的需求,电取暖的方式得到大力的推广,电热材料的研究与应用受到人们广泛的重视。非金属碳基电热材料是新型的节能型电热采暖材料,本文重点对影响非金属碳基电热材料中的炭黑基电热材料、碳纤维基电热材料、碳晶电热材料电热性能的因素及相关应用进行了综述。     

黑匣子高温测试仪的开发

采用物质的相变吸热原理，可以将高温环境传人保温箱的热量重新排回至高温环境，有效地提高了保温箱的抗高温能力，并对保温箱的隔热性能做了简单的理论推算和测温反向试验。温度测试仪选用超低功耗CPU，具有体积小、耗电少的优点，使黑匣子高温测试仪在运行过程中具有很好的安全可靠性。     

数字化蓄热式钢包烘烤器及自动控制系统

蓄热式燃烧技术和脉冲燃烧技术是新型的节能环保燃烧技术。数字化蓄热式钢包烘烤器控制系统利用数字化脉冲控制把这两项技术结合在一起。这大大降低了能耗，减少环境污染。本文针对数字化蓄热式钢包烘烤器，提出升温阶段采用自寻优算法，不断调整换向时间，并能记忆最优参数，保证经过几次烘烤后系统整体最优；保温阶段即采用脉冲控制的方法。     

微波合成无机纳米材料的研究进展

微波加热作为一种合成纳米材料的新方法，近年来得到飞速发展。介绍了微波加热原理，阐述了微波合成无机纳米材料的一些研究进展，主要是液相微波加热在制备金属氧化物和金属硫化物纳米材料以及微波烧结在合成陶瓷材料的应用，并对该领域未来作了一些展望。     

广州清洁燃料汽车发展方向

选择好合适的汽车替代燃料，科学确定一个地区清洁燃料汽车的发展方向，是减少机动车有害尾气排放、控制城市大气环境污染重大而紧迫的课题。国内外汽车清洁燃料的发展规律表明，天然气特别是液化天然气，是汽车替代燃料的最佳选择与发展方向。为此，探讨了随着天然气工业的加快发展，作为广州这样一座已经发展液化石油气汽车并已形成有一定规模的城市，如何适应新形势的需求，科学决策，选择符合国家能源发展政策并适应当地具体实际的汽车清洁燃料路线，寻求顺利实施液化石油气与天然气两种清洁燃料平稳过渡的具体措施。最后提出以下建议：加速LNG加气站和液化天然气汽车（LNGV）相关技术规范的制定；加快实现LNG关键设备，如LNG泵、LNG售气机、车用LNG储罐的国产化步伐，以降低LNGV和加气站的成本；鉴于LNGV改装技术的现状，不提倡对在用车进行改装，而应加大力度，逐步推广单燃料LNG汽车。