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81.
82.
为满足含能材料高能钝感的要求,以CL-20为主体炸药,LLM-105为钝感剂,采用溶液水悬浮法制备了LLM-105质量分数分别为10%、20%、30%的3种LLM-105/CL-20基PBX。通过扫描电子显微镜(SEM)、粉末X射线衍射仪(PXRD)和差示扫描量热仪(DSC)对样品的形貌、晶体结构和热性能进行表征,并测试其机械感度;采用EXPLO5软件计算了其爆轰参数。结果表明,LLM-105/CL-20基PBX样品呈类球形,颗粒密实,粒径约为500μm;PBX中各组分的晶体结构未发生改变;3种配方的热安定性都较好,且随着钝感剂LLM-105含量的增加,LLM-105/CL-20基PBX的热爆炸临界温度呈递增趋势;与原料CL-20相比,3种LLM-105/CL-20基PBX的特性落高分别提高了25.88、33.68、37.18 cm,摩擦爆炸概率分别下降29%、38%、45%;LLM-105质量分数为10%的LLM-105/CL-20基PBX的特性落高与PBX-9501相当,而LLM-105质量分数为20%和30%的LLM-105/CL-20基PBX分别比PBX-9501高16.6%和25.12%;理论爆速分别高381.76、279.2、82.03 m/s。3种配方LLM-105/CL-20基PBX炸药的爆轰性能明显优于PBX-9501。 相似文献
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为促进变几何涡轮在航空发动机中的广泛应用,提高变几何涡轮的工作效率,设计了一种用于变几何涡轮的摆杆式导叶调节机构。采用Adams软件对导叶调节机构进行了运动学仿真研究,仿真结果验证了调节机构设计的可行性,通过仿真发现这样的导叶调节机构至少需采用3个作动筒同时驱动才能保证涡轮调节的精度要求。在Adams中对机构进行了参数化建模,利用参数化模型分析了尺寸误差和间隙对导叶转动精度的影响,并且以前十次仿真为例计算了调节机构导叶角度重复位置精度的可靠度。研究结果表明设计的导叶调节机构结构合理、可靠性高。 相似文献
86.
Brandon Tonnis Ming Li Wang Xianran Li Jianping Wang Naveen Puppala Shyam Tallury Jianming Yu 《Journal of the American Oil Chemists' Society》2020,97(9):1001-1010
The level of oleic acid is an important parameter in determining seed nutritional quality and oil stability. The level of oleic acid in peanut is genetically controlled by a pair of fatty acid desaturase genes (FAD2A and FAD2B), but the environmental conditions of the production sites can also have a significant effect. To investigate the effect of gene and environment interaction, 45 accessions were grown at three locations for 2 years. Environmental data were collected; individual plants were genotyped with functional SNP markers from FAD2A and FAD2B; and seed level of oleic acid was determined by gas chromatography. Three FAD2A/FAD2B genotypes (448G/no insertion 442A, 448A/no insertion 442A, and 448A/insertion 442A) were identified and designated as G/W, A/W, and A/A, respectively. A/A genotype averaged the highest level of oleic acid (80.0%), followed by A/W (56.0%), and then G/W (40.7%). Analysis of gene and environment interaction revealed that oleic acid phenotype plasticity could be explained by the interaction of FAD2 genotype and photothermal time, which quantified environmental conditions. The A/W genotype was the most sensitive to photothermal time changes. The oleic acid plasticity revealed in this study would be useful for breeders, farmers, and product processors. 相似文献
87.
CAT02, the most widely used chromatic adaptation transform to characterize the chromatic adaptation mechanism in the human visual system, includes a factor D to characterize the degree of chromatic adaptation. This factor, however, is only determined by the luminance level of the adapting field and surround. This study was designed to investigate how the change of adapting chromaticities and the simultaneous changes of adapting chromaticities and luminance affect the degree of chromatic adaptation and color appearance on computer displays. The human observers adjusted the color appearance of various familiar objects and cubes on different display backgrounds. A higher degree of chromatic adaptation was found when using familiar objects, which was likely due to the cognitive mechanism. Both the adapting chromaticities and luminance significantly affected the degree of chromatic adaptation, with a lower degree under an adapting condition with a lower adapting correlated color temperature and a lower adapting luminance. In addition, the effect of adapting luminance on colorfulness (known as the Hunt Effect) was likely to be overpredicted in CAM02-UCS, which merits further investigations. 相似文献
88.
萃取塔因生产能力大、占地面积小、密闭性好等优点,在石油、化工、生物、医药和环境工程等多领域被广泛应用。本文从以下几个方面介绍了萃取塔近些年的研究进展:综述了传统萃取塔(脉冲萃取塔、转盘塔与Kühni塔等)的水力学、轴向扩散与传质模型的发展,分析比较了表面张力、传质方向、放大效应等因素对模型的影响;介绍了计算流体动力学(CFD)在萃取塔中单液滴、单相流模拟、液-液两相流模拟、外加能量模拟、与群体平衡模型(PBM)耦合模拟中的应用进展;介绍了国内外设计开发的新型萃取塔,包括改变传统塔的内构件和引入多种外场能量等方式来强化相间传质。研究表明,将先进实验研究方法、准确经验模型和可靠理论计算相结合,将会是萃取塔研究的重要手段和方向。 相似文献
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Jiaojiao Gao Jinpeng Song Ming Lv Lei Cao Juncai Xie 《Ceramics International》2018,44(15):17895-17904
TiC0.7N0.3-HfC cermet tool materials were fabricated by hot-press sintering. Effects of different metal additives (Ni, Co, Ni-Co and Ni-Mo), sintering temperature and holding time on the microstructures and mechanical properties of TiC0.7N0.3-HfC cermets were investigated. Results showed that Ni-Mo or Ni-Co as metal additives was better for the mechanical properties of TiC0.7N0.3-HfC cermets than only Ni or only Co as the metal additives and Ni-Mo better than Ni-Co. HfC particle dispersion existed in these four cermets and only in the TiC0.7N0.3-HfC-Ni-Mo cermet the core-rim structure obviously existed. TiC0.7N0.3-HfC-Ni-Mo cermet had significantly smaller grains than the other three cermets because Ni-Mo can significantly refine the grain. With the sintering temperature increasing from 1450?°C to 1650?°C, grains grew gradually; Vickers hardness and flexural strength decreased gradually and the fracture toughness increased firstly and then decreased. With the holding time increasing from 15?min to 60?min, grains grew gradually; Vickers hardness, flexural strength and the fracture toughness increased firstly and then decreased. TiC0.7N0.3-HfC-Ni-Mo cermets sintered at 1450?°C with 30?min holding time had the better comprehensive mechanical properties with flexural strength of 1346.41?±?31?MPa, fracture toughness of 8.46?±?0.23?MPa?m1/2 and Vickers hardness of 22.91?±?0.22?GPa. 相似文献