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排序方式: 共有2475条查询结果,搜索用时 31 毫秒
1.
Sumeng Wei Yining Xu Baohua Kong Meijuan Wang Jingming Zhang Qian Liu Yuling Yang 《International Journal of Food Science & Technology》2022,57(8):5024-5035
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. 相似文献
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Public-private partnerships (PPPs) are predominantly executed through the use of formal contracts which define the relationship between a public agency and private supplier. As such, a PPP is not a generic contract between buyer and supplier but rather a specific contractual arrangement between a public buyer and private supplier. The contract captures the responsibilities of each party in achieving a specific set of performance objectives. Given budgetary pressures faced by public agencies, there is an increasing need for suppliers to make investments which could reduce future-year costs of meeting contract performance objectives. This research addresses two overarching questions specific to the issue of private, supplier-side investment. First, “how does public agency and private supplier perception of risk influence contract duration?” and second, “how does contract duration influence private investment?” To answer these questions, structured interviews were conducted with those in public agencies and private, supplier firms actively engaged in PPPs. Factors suspected to contribute to the risk position of public and private actors were evaluated. Additionally, linkages between public buyer-private supplier risk position, contract duration and private, supplier-side investment were addressed. Outcomes suggest properly structured long-term contracts may: 1) provide the risk mitigation mechanisms needed for both public and private actors, and 2) facilitate private, supplier-side investment. 相似文献
3.
《International Journal of Hydrogen Energy》2019,44(36):20587-20597
In this study, a series of full-scale high-pressure natural gas pipeline physical explosion experiments were performed, in which the overpressure of the shock waves was measured and analyzed. The concept of “physical explosion linear energy (PEXLE)” was proposed and a “PEXLE model” was established to evaluate shock waves in a cylindrical pipeline with high length–diameter ratio. Equations were fitted to describe the characteristics of peak overpressure, positive pressure duration and specific impulse. Results showed that peak overpressure of shock waves is not influenced by the length of pipeline. With the increase of the propagation distance, specific impulse first increases and then decreases. This indicates that the position of the maximum value of overpressure does not correspond with that of the specific impulse. 相似文献
4.
Research on the hot surface ignition of hydrogen‐air mixture under different influencing factors 下载免费PDF全文
To further reveal the pre‐ignition characteristics of hydrogen internal combustion engine, the effect of hot surface characteristic parameters on the ignition characteristics of hydrogen‐air mixture was investigated in this research. Based on the prototype of the constant volume combustion bomb with an overhead glow plug, the duration from the heating of the hot surface to the combustion of hydrogen‐air mixture, the so‐called heating duration, was firstly researched under different fuel‐air equivalence ratio, initial temperature, initial pressure, hot surface temperature, and hot surface area, and the influence of each factor on the heating duration was analyzed. The results show that the order of the effect of each factor on the hot surface ignition is as follows: hot surface temperature > initial pressure of hydrogen‐air mixture > equivalent ratio > initial temperature of hydrogen‐air mixture > hot surface area. The influence of the hot surface characteristic parameters on the heating duration was further analyzed in detail. On this basis, the relationship among the critical ignition temperature, the heating duration and the hot surface area was researched and established. The results show that the heating duration is the only major factor affecting the critical ignition temperature. Finally, the research results were applied to analysis the pre‐ignition in hydrogen internal combustion engine. 相似文献
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我国酸雨状况及综合防治对策研究 总被引:4,自引:0,他引:4
本文详细论述了酸雨及其形成机理、危害和我国酸雨状况,指出了我国防治酸雨的必要性,提出了酸雨综合防治的策略。结合北京市的特点,探讨了北京市酸雨防治的对策。 相似文献
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绿色生态住区的水环境建设 总被引:5,自引:1,他引:5
从分析住区水环境的现状入手,针对当前住区水环境建设中存在的一些问题,从自然化,生态化的角度论述如何提高提高住区生态环境质量,对合理进行水环境建设提出了一些措施。 相似文献
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