共查询到20条相似文献，搜索用时 156 毫秒
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实验采用高温热爆的方法,将Ni-Al粉末压坯进行反应合成,同时测得实验中燃烧温度曲线。通过与合成体系绝热燃烧温度热力学计算结果进行对此,发现实验温度此计算略低。应用热力学原理,分析该燃烧合成体系的平衡产物相为NiAl和Ni3Al。热爆合成产物经XRD分析及SEM显微组织观察与热力学分析结果相吻合,说明该燃烧合成反应进行的较为彻底。 相似文献
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DNA计算是解决困难问题的一种很重要的方法。应用DNA计算解决图论中的最小支撑树问题。利用DNA的热力学特性,根据边的权长不同,给它们设计不同溶解温度的DNA链。根据温度的不同,电泳时DNA分子的形状不同,电泳的速度也不同,从而根据电泳速度分离出最小支撑树的所有边。在这里给出了5个顶点的赋权图为例来求它的最小支撑树,说明了该方法的简便性。 相似文献
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李凯 《大科技．科学之谜》2014,(4):199-200
研究了单宁酸改性蒙脱石对镉的吸附热力学。在同一温度下,单宁酸改性蒙脱石对镉的吸附量随镉浓度的增加呈现一个先增加然后平衡的过程,吸附过程能很好的符合Langmuir方程和Lagergren二级方程;对不同温度下（20-50℃）吸附过程各热力学参数（△H、△C、△S）的计算说明,单宁酸改性蒙脱石对镉的吸附是～个自发的吸热过程。 相似文献
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陈佩芳 《内蒙古科技与经济》2020,(13)
建立了一种采用生命周期成本分析方法研究建筑材料的最佳绝热厚度的模型,该方法是一种基于度日数方法和生命周期成本分析的分析优化方法,目标函数是生命周期成本最小化,控制变量包括绝热厚度、绝热材料和墙体材料的热导率;采用该模型对玻璃棉绝热的粘土砖墙体材料进行了分析计算,结果表明,粘土砖墙体材料采用玻璃棉进行绝热时,最优绝热厚度为37.4mm。 相似文献
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制备了一个简易绝热型热量计,并用此热量计实测了７种非均相电解质水溶液在５～６０℃范围内不同温度区间的比热容,提出了比热容与温度的经验关联式。关联式的计算值和实验值的平均相对偏差均小于１％。热量计采用标准物质正庚烷标定,装置的测量精度为０．９％。 相似文献
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《科技风》2016,(16)
基于高钢级管线钢的成分体系,建立双亚点阵模型:(Nbx,Ti1-x)(Cy N1-y)-Al N复合析出的热力学模型,计算出800℃~1450℃温度区间内两种不同Nb含量的管线钢中碳氮化物复合析出数据,并于Jmatpro软件计算结果进行比较,结果表明:Nb含量的增加,提高了Nb的全固溶温度,扩大了高温析出温度区域;Ti元素1200℃~1450℃温度区间内析出速度很快,1200℃时两种成分钢中Ti的析出量均大于50%;800℃平衡态时,析出物均以Nb C为主;Nb对Ti元素的交互作用,间接影响到Al N的析出。热力学计算结果与JMatpro软件计算结果进行比较,试验数据有着良好的一致性。 相似文献
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A procedure is described for determining the characteristics of adiabatic flow through a rocket nozzle with and without composition change. The method of calculation is illustrated for the expansion of pure hydrogen gas from a chamber temperature of 306° K. and a pressure of 20.42 atm. to atmospheric pressure.The study indicates that the exhaust velocity and temperature are highest for flow where complete equilibrium is reached at each temperature with respect to the reaction Flow with composition change requires a nozzle exit to nozzle throat area ratio somewhat greater than that determined for adiabatic flow without composition change for the same ratio of chamber pressure to exit pressure.The residence time in a given temperature range is computed as a function of gas temperature for the two types of flow. The results of this calculation may be used to determine the minimum required reaction rates which allow composition changes during flow through the nozzle. 相似文献
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适用于中尺度系统研究的位涡方程 总被引：1，自引：0，他引：1
本文通过推导绝热、无摩擦大气方程组，讨论了新方程组的特点；新方程组中，位温 显式出现在动量方程中，有利于探讨倾斜的等熵面（等位温面）对中尺度系统发生和发展的影响。进一步，利用此新方程组，推导出适用于中尺度系统研究的新的位涡方程，新位涡方程突出的特点是，与中尺度系统发生、发展密切相关的散度项显式出现在方程的右端；这为研究中尺度系统演变过程中，辐合、辐散效应对系统位涡收支的影响、进而研究中尺度系统发生、发展的热、动力学过程提供了方法。 相似文献
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B.V. Korvin-Kroukovsky 《Journal of The Franklin Institute》1938,225(1):81-93
The efflux of gases through orifices was treated heretofore on basis of adiabatic expansion, postulating the decrease of temperature, which is not observed in the facts of everyday experience. The consideration of molecular motion on the principles of the Kinetic Theory of Gases shows the possibility of the expansion of a gas flowing through an orifice without change of temperature, and permits the formation of simple quantitative relations which are in a satisfactory agreement with test data. For small difference in pressure the new expression for discharge becomes identical with Fliegner's formula. It is explained that reduction of temperature postulated by adiabatic formulæ should be understood to apply to the observer moving with stream, and that no change of temperature is registered by stationary observer. The possibility of extension of the adiabatic and of the new “kinetic” formulæ to the pressure ratios below critical is opened by the consideration of reduced number of impacts between molecules with reduction of the pressure ratio. 相似文献
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Mohamad Sleiman Rachid Bouyekhf Adbellah El Moudni 《Journal of The Franklin Institute》2019,356(1):351-381
The paper explores the application of thermodynamic formalism to model and control transportation networks. Specifically, by considering the vehicles as the abstract energy supplied to the system, we show in certain circumstances that certain thermodynamic concepts such as temperature, thermal capacity and thermal equilibrium can have the corresponding notions in transportation context. In addition, despite the lack of a natural principle in transportation context that corresponds to the second law of thermodynamic as we will show, the most important thermodynamic notion, which is the entropy, can be also defined in order to measure the disorder of transportation systems. It is then shown that the state when all lanes have the same occupancy corresponds to the thermal equilibrium arising in isolated thermodynamic system. This equilibrium occupancy leads to a minimum entropy corresponding to a minimal disorder. Besides, by taking the transportation entropy as the storage function, a robust dissipativity based control strategy is presented to reduce the disorder and render the system better organized. Finally, an example is worked out to illustrate the results. 相似文献
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研究广义Birkhoff系统Lie对称性的摄动与绝热不变量.首先,列写出广义Birkhoff系统的运动微分方程;其次,基于微分方程在无限小变换下的不变性,研究了广义Birkhoff系统的Lie对称性,给出了系统Lie对称性直接导致的Hojman守恒量,并进一步研究在小扰动作用下Lie对称性的摄动,得到了系统的Hojma... 相似文献
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在对科技成果经济效益评价理论、方法研究分析基础上,结合石油工程类科技成果的特点,从经济效益评价计算角度确定适合石油工程行业经济效益计算的成果分类体系;针对不同成果类型建立多个适应性强的经济效益评价计算模型,通过实例测算分析,证明该计算模型科学可靠,为石油工程类科技成果经济效益计算和投入产出量化评价提供一套科学、实用的方法和工具。 相似文献
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污染物的排放方式对水环境容量的大小至关重要,不同的水环境容量条件对应不同的旅游业规模和布局,不同的旅游业规模和布局又对污染物排放方式产生较大的影响。本文根据不同污染物种类和排放模式,对泸沽湖水环境容量的一般值和保守值进行了估算,在不同水环境容量条件下模拟了旅游业人口容量的情景,并与传统方法计算的旅游人口容量进行了比较。结果表明,按完全混合模式（集中排放模式）条件下的总磷水环境容量,计算的保守旅游人口容量为15.8×104人/d;以2004年现状排放量、扩散半径30 m条件下的总磷水环境容量为基础,计算的保守旅游人口容量为3.3×104人/d;按照可游览面积法计算,确定的保守旅游人口容量为3.95×104人/d。从保护湖体水环境的角度来讲,建议选择较低的旅游人口环境容量,即以分散模式布局旅游业、且以总磷水环境容量为基础计算的旅游人口容量为最高值控制旅游规模,即3.3×104人/d,可有效保护湖体水质。 相似文献
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Arthur K. Doolittle 《Journal of The Franklin Institute》1973,295(3):217-237
A volume—entropy—energy (VSE) equation of state, unlike a PVT equation of state, can be used to calculate “all conceivable” thermodynamic quantities, including specific heats, without supplemental calorimetric data. A VSE equation for liquids, based on simple theoretical concepts, is proposed and, in this paper, applied specifically to n-heptane. This equation of state requires only ten arbitrary parameters, seven of which may be calculated from data at but three temperatures, e.g., 25°, 50° and the normal boiling point. It yields calculated values of many thermodynamic properties nearly as accurate as the best experimental data, from a few degrees above the melting temperature all the way to the critical temperature. PVT equations of state of comparable accuracy over such broad ranges would require at least as many parameters, as well as supplemental calorimetric data, to calculate many thermodynamic quantities that are obtainable directly from our VSE equation. 相似文献