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排序方式: 共有2123条查询结果,搜索用时 62 毫秒
1.
《Egyptian Journal of Petroleum》2019,28(4):377-382
Four hydrocarbon-base gasolines (BG) were formulated from the local refinery streams; isomerate, reformate, and light naphtha. The formulations were enriched in reformate. Each of these BG formulations was blended with 10 vol% of anhydrous ethanol. From ASTM-D86 distillation data, eight distillation curves were constructed and the trend line equations of these distillation curves were developed. Also, the area under each distillation curve (AUDC) was calculated through calculus definite integration technique. Subsequently, the area due to azeotrope formation (ADAF) for each BG-ethanol blend was estimated. In this paper, the influence of increasing reformate proportions on the created positive azeotrope, was studied. Also the influence of increasing reformate proportions on vapor pressure, Temperature for the vapor-liquid ratio of 20, T50 and octane number was studied. The results show that the R2 values of the distillation curve equations prove the reliability of the fits. Also, increasing reformate proportion in the fuel blend improves the octane number while increasing reformate proportion decreases the volatility of the fuel formulation. 相似文献
2.
装配式建筑相较于传统建筑,具有节能减排、绿色环保、快速施工、工业化生产和缩短工期等优势,能有效改善我国现阶段建筑业劳动力低、技术创新弱、建筑品质不高的局面,推动建造方式的改变,并能大幅提高企业信息化、可视化管控管理水平,并通过预制装配式产业链的整合,催生相关新产业和服务业,可以使产业链上各企业的核心竞争力得到提高。全产业标准化,规格化,使得信息流、资金流和物流得到有效整合。 相似文献
3.
目的以月柿提取物为原料,研究其对2,2-联苯基-1-苦基肼基(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基的清除能力,并测定其多酚类物质没食子酸的含量。方法检测波长为518 nm,反应时间为40 min条件下,以IC_(50)值(清除率为50%时,抗氧化剂的浓度值)作为抗氧化能力评价指标,并采用高效液相色谱法测定其没食子酸含量。结果月柿提取物对于DPPH自由基有良好的清除作用,其IC50值为0.1868 mg/mL,与常用抗氧化剂作用相当,且月柿提取物中没食子酸含量为1.65 g/kg。结论月柿提取物具有很强抗氧化活性,作为化妆品及功能性食品原料有广阔的开发前景。 相似文献
4.
《Advanced Powder Technology》2020,31(1):279-286
To explore the potential application of industrial waste, steel slag powder in combination with melamine pyrophosphate (MPP) was adopted to improve the flame retardancy of rigid polyurethane foam (RPUF). The incorporation of steel slag slightly reduced the thermal conductivity of the resulting flame-retardant RPUF samples. The addition of MPP and/or steel slag did not significantly alter the thermal stability in terms of T-10% and Tmax but did obviously increase the T-50% value, suggesting the improved thermal resistance of the residues. The coaddition of MPP and steel slag into RPUF resulted in higher LOI values and lower peak heat release rates than the samples incorporating either MPP or steel slag alone. The superior flame retardancy could be attributed to MPP promoting char formation, which then acted as a barrier at the beginning of RPUF thermal decomposition; simultaneously, the thermally stable inorganics in the steel slag powder strengthened the thermal resistance of this char layer. 相似文献
5.
以二氯乙二肟、二甲基甲酰胺、叠氮化钠、盐酸羟胺和硝酸铅等为原料,合成了1,1-二羟基-5,5′-联四唑羟胺铅盐(Pb-TKX-50)燃烧催化剂,研究了Pb-TKX-50对推进剂机械感度的影响以及与推进剂组分的相容性;利用差示扫描量热法和热重法研究了Pb-TKX-50在不同升温速率下的热分解过程,计算其表观活化能(E K和E O)和指前因子(A K),得到其热分解动力学参数、热分解机理函数、热爆炸温度和热力学性质。结果表明,在推进剂配方中加入Pb-TKX-50燃烧催化剂,可以改善其撞击感度和摩擦感度,且与推进剂组分的相容性良好;Pb-TKX-50的主峰分解温度相对于TKX-50的主峰分解温度显著提高,说明其热稳定性显著提高。Ozawa法和Kissinger法得到Pb-TKX-50的表观活化能分别为181.45 kJ/mol和182.49 kJ/mol,且热分解过程符合Avrami-Erofeev方程;Pb-TKX-50的自加速分解温度和爆炸临界温度分别为500.53 K和544.33 K,表明其热稳定性良好;Pb-TKX-50催化剂的热分解自由能(ΔG^≠)为158.87 kJ/mol,活化焓(ΔH^≠)为187.03 kJ/mol,活化熵(ΔS≠)为52.98 kJ/mol。 相似文献
6.
《International Journal of Hydrogen Energy》2022,47(9):6388-6403
The influence of electrochemical charging of hydrogen at j = ?5 mA/cm2 for 6, 12, 48 and 96 h on the structural and the mechanical behavior of wrought and electron beam melting (EBM) Ti–6Al–4V alloys containing 6 wt% β and similar impurities level was investigated. The length of the α/β interphase boundaries in the EBM alloy was larger by 34% compared to that in the wrought alloy. The small punch test (SPT) technique was used to characterize the mechanical behavior of the non-hydrogenated and hydrogenated specimens. It was found that the maximum load and the displacement at maximum load of the wrought alloy remained nearly stable after 6 h of charging, showing a maximum decrease of ~32% and 11%, respectively. Similarly, hydrogenation of the EBM alloy resulted in a gradual degradation in mechanical properties with charging time, up to ~81% and 86% in pop-in load and displacement at the “pop-in” load, respectively. The mode of fracture of the wrought alloy changed from ductile to semi-brittle with mud-cracking in all hydrogenated specimens. In contrast, the mode of fracture of the EBM alloy changed from a mixed mode ductile-brittle fracture to brittle fracture with star-like morphology. The degraded mechanical properties of the EBM alloy are attributed to its α/β lamellar microstructure which acted as a short-circuit path and enhanced hydrogen diffusion into the bulk as well as δa and δb hydride formation on the surface. In contrast, a surface layer with higher concentration of δa and δb hydrides in the wrought alloy served as a barrier to hydrogen uptake into the bulk and increased the alloy resistivity to hydrogen embrittlement (HE). This study shows that EBM Ti–6Al–4V alloy is more susceptible to mechanical degradation due to HE than wrought Ti–6Al–4V alloy. 相似文献
7.
8.
本文生要研究了甲嘧磺隆对鲈鱼、蛏两种主要的滩涂养殖生物进行了急性毒性研究,为甲嘧磺隆用于滩涂防治互花米草提供科学依据。结果表明:处理96h后对于鲈鱼和蛏的半致死浓度(LC50)分别为151.322和374.450mg/L,甲嘧磺隆对两种实验动物急性毒性属于低毒,对于两种滩涂养殖动物在急性毒性方面没有明显影响。 相似文献
9.
This article develops an improved seismic risk assessment formulation exhibiting both random and bounded uncertainties using a probability and parallelepiped convex set mixed model. Limit thresholds for different types of components are described via a probabilistic model. The distribution parameters of limit thresholds are originally treated by employing a multidimensional parallelepiped convex model, in which marginal intervals are utilised to represent scattering levels for the distribution parameters, while relevant angle are employed to express the correlation between uncertain distribution parameters. The structural responses, i.e., engineering demand parameters (EDPs), are considered as correlated random variables and are assumed to follow a multidimensional lognormal distribution. A performance limit state function, which allows considering the relationship between the EDPs and the corresponding limit thresholds, is employed to reflect the coexistence of both random and parallelepiped convex variables. The limit state function is mapped into the standard parameter space via a transformation technique. Then, the improved seismic risk formulation, characterised through a probability and parallelepiped convex mixed variables, can be derived with the combination of the seismic fragility function and the ground motion hazard curve. The main purpose is to illustrate that the performance limit states should be properly modeled as random and parallelepiped convex mixed variables rather than only random or deterministic quantities. A six-story reinforced concrete building designed according to Chinese codes are used to illustrate the proposed approach for constructing hazard curves. The interstory drift and the peak floor acceleration are the selected EDPs, calculated through incremental dynamic analysis. The results demonstrate that the calculated failure probabilities for different limit states in 50?years are found capable of meeting the requirements of Chinese seismic norms after the proposed seismic risk formulation is adopted. 相似文献
10.