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11.
由于市场的局限性和设备创造价值的不可分割性,重置成本法在机电设备评估实践中得到了广泛应用。但在应用该方法获取评估值时,对于基本公式的选择以及三大贬值或综合成新率的确定目前存在很大分歧。基于重置成本法的基本公式和定义,综合考虑了机器设备的有形损耗和无形磨损,以实体性贬值、功能性贬值和经济性贬值为基础建立了因素集,并建立了科学合理的计算设备价值的方法,对评估价值量较小且单一的机械设备的价格具有一定的实际意义和参考价值。 相似文献
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High‐performance thermosets with tailored properties derived from methacrylated eugenol and epoxy‐based vinyl ester 下载免费PDF全文
Yuehong Zhang Yuzhan Li Vijay Kumar Thakur Zhenhua Gao Jiyou Gu Michael R Kessler 《Polymer International》2018,67(5):544-549
A renewable chemical, eugenol, is methacrylated to produce methacrylated eugenol (ME) employing the Steglich esterification reaction without any solvent. The resulting ME is used as a low‐viscosity co‐monomer to replace styrene in a commercial epoxy‐based vinyl ester resin (VE). The volatility and viscosity of ME and styrene are compared. The effect of ME loading and temperature on the viscosity of the VE–ME resin is investigated. Moreover, the thermomechanical properties, curing extent and thermal stability of the fully cured VE–ME thermosets are systematically examined. The results indicate that ME is a monomer with low volatility and low viscosity, and therefore the incorporation of ME monomer in VE resins allows significant reduction of viscosity. Moreover, the viscosity of the VE–ME resin can be tailored by adjusting the ME loadings and processing temperature to meet commercial liquid molding technology requirements. The glass transition temperatures of VE–ME thermosets range from 139 to 199 °C. In addition, more than 95% of the monomer is incorporated and fixed in the crosslinked network structure of VE–ME thermosets. Overall, the developed ME monomer exhibits promising potential for replacing styrene as an effective low‐viscosity co‐monomer. The VE–ME resins show great advantages for use in polymer matrices for high‐performance fiber‐reinforced composites. This work is of great significance to the vinyl ester industry by providing detailed experimental support. © 2018 Society of Chemical Industry 相似文献
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近年来,由集成电路(IC)供应链的全球化带来的硬件木马电路威胁引发了广泛的关注。现有运行阶段针对不可信第三方知识产权核(3PIP)的木马电路检测技术没有考虑到检测到木马电路时被感染IP核的定位和替换问题,使得系统时间性能开销增加、可靠性下降。为了解决该问题,基于IP核多样性和现有的木马电路检测和出错恢复架构,提出了一个面向开销优化的被感染IP核定位和替换的解决方案。定位技术通过检测阶段存储结果和恢复阶段运行结果的实时比较实现,并在理论上证明了定位的准确性;替换技术通过可编程逻辑实现,能够最小程度地影响系统下次的正常运行。实验表明,在检测到木马电路时,被感染IP核的定位技术相比于已有的木马电路检测和恢复技术能够平均提升25%的系统时间开销。提出的定位和替换方案对于使用不可信单元建立可信计算系统,以及加强系统的安全性具有一定的指导意义。 相似文献
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The first 2 generations from a 3-breed rotation of the Viking Red (VR), Montbéliarde (MO), and Holstein (HO) breeds were compared with their HO herdmates in high-performance commercial herds in Minnesota. The designed study enrolled pure HO females in 2008 to initiate a comparison of 3-breed rotational crossbreds with their HO herdmates. Sires of cows were proven artificial insemination bulls selected for high genetic merit in each of the 3 breeds. The first-generation cows calved for a first time from 2010 to 2014 and had 376 VR × HO and 358 MO × HO crossbreds to compare with their 640 HO herdmates. The second-generation cows calved for a first time from 2012 to 2014 and had 109 VR × MO/HO and 117 MO × VR/HO crossbreds to compare with their 250 HO herdmates. Collection of data ceased on December 31, 2017, and all cows studied had the opportunity for 45 mo in the herd after first calving. Production of milk, fat, and protein (kg) during lifetimes of cows was estimated from test-day observations with best prediction. The lifetime profit function included revenue and cost. Revenue was from production, calves, and slaughter of cull cows. Costs included feed cost during lactation, lactating overhead cost, dry cow cost (including feed cost during dry periods), replacement cost, health treatment cost, insemination cost, fertility hormone cost, pregnancy diagnosis cost, hoof trimming cost, and carcass disposal cost. For individual cows with herd life longer than 45 mo after first calving, survival of cows was projected beyond 45 mo after first calving to estimate herd life, production, and profitability. The 2-breed crossbreds had +158 d longer herd life and the 3-breed crossbreds had +147 d longer herd life compared with their respective HO herdmates. Also, 12.4% of the 2-breed crossbreds died up to 45 mo after first calving compared with 16.3% of their HO herdmates. Furthermore, approximately 29% of both the 2-breed and 3-breed crossbreds lived beyond 45 mo after first calving compared with approximately 18% of their respective HO herdmates. On a lifetime basis, the 2-breed and 3-breed crossbreds provided +$122 and +$134, respectively, more cull cow revenue compared with their HO herdmates. For lifetime replacement cost, the 2-breed crossbreds did not differ from their HO herdmates; however, the 3-breed crossbreds had ?$28 less lifetime replacement cost compared with their HO herdmates because of their younger age at first calving. The combined 2-breed crossbreds had +$0.473 (+13%) more daily profit (ignoring potential differences for feed efficiency) and the combined 3-breed crossbreds had +$0.342 (+9%) more daily profit compared with their respective HO herdmates. This resulted in +$173 more profit/cow annually for the combined 2-breed crossbreds and +$125 more profit/cow annually for the combined 3-breed crossbreds compared with their respective HO herdmates. 相似文献
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本文对直接计算条形基础和短形基础换土垫层厚度的方法进行了探讨,建立力平衡方程直接计算,可不需试算就可直接算出换土垫层厚度。 相似文献
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采用抛填卵石挤淤置换并辅以强夯对淤泥地基进行了处理,对处理后的地基进行了钻探、重型动力触和浅层平板载荷试验,表明此方法加固效果显著。 相似文献
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中国能源形势和政策浅析 总被引:1,自引:3,他引:1
在分析中国各种能源资源供需形势、供应潜力和新型能源开发利用进展情况的基础上,提出中国能源政策的战略选择应是立足国内,加大非煤能源开发利用力度,提高能源利用效率,保持较低的对外依存度。我国完全有能力保证经济社会发展对能源的需求,最终实现对能源利用的平稳的更新换代。 相似文献
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大型洞室群稳定性与优化的并行进化神经网络有限元方法研究--第二部分:实例研究 总被引:5,自引:4,他引:5
利用作者提出的并行进化神经网络有限元方法对水布垭地下厂房进行了软岩置换方案的优化及稳定性分析。结果表明,该方法具有极大的全局搜索和快速收敛的优势.实例给出了最优的置换方案和置换步骤,通过最优方案的有限元与神经网络的计算比较表明,该方法是合理的。同时,提出了施工的合理化建议。 相似文献