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51.
根据实验测定的相图,运用CALPHAD技术对ErCl3-CaCl2体系进行了热力学优化和计算.计算出的相图属于简单低共熔型,低共熔点为850.92K,46.0%(摩尔分数)ErCl3,同时优化计算了该体系的液相混合焓和相互作用系数.这些热力学参数对于稀土金属及其合金的冶炼有重要意义. 相似文献
52.
鲁春发 《十堰职业技术学院学报》2011,24(2):101-103
通过对移动从动件凸轮轮廓曲线的几何分析,运用三心定理得出凸轮压力角的计算公式,用Excel准确计算出凸轮轮廓曲线上各点的压力角后运用图表分析不同运动规律、不同升程及不同偏心距的情况下凸轮轮廓曲线上各点压力角的变化规律。 相似文献
53.
酒明衍 《南阳师范学院学报》2011,10(3):40-42
测定了四元体系RbBr-CeBr3-HBr-H2O在25℃时的溶度数据,绘制了相应的溶度图.该四元体系由2个固相区RbBr(原始盐),CeBr3.6H2O(原始盐)组成,是一简单共饱型体系.双饱点组成(平均值)为:HBr 13.34%,CeBr344.15%,RbBr 6.84%.与文献报道的此类氯化物体系比较发现,溴化物体系与氯化物轻稀土体系有较大的相化学关系差异,其原因可能是溴阴离子半径较大所致. 相似文献
54.
Ningsi Zhang Xin Wang Jianyong Feng Huiting Huang Yongsheng Guo Zhaosheng Li Zhigang Zou 《国家科学评论(英文版)》2020,7(6):1059
Although β-Fe2O3 has a high theoretical solar-to-hydrogen efficiency because of its narrow band gap, the study of β-Fe2O3 photoanodes for water splitting is elusive as a result of their metastable nature. Raman identification of β-Fe2O3 is theoretically and experimentally investigated in this study for the first time, thus clarifying the debate about its Raman spectrum in the literature. Phase transformation of β-Fe2O3 to α-Fe2O3 was found to potentially take place under laser and electron irradiation as well as annealing. Herein, phase transformation of β-Fe2O3 to α-Fe2O3 was inhibited by introduction of Zr doping, and β-Fe2O3 was found to withstand a higher annealing temperature without any phase transformation. The solar water splitting photocurrent of the Zr-doped β-Fe2O3 photoanode was increased by 500% compared to that of the pure β-Fe2O3 photoanode. Additionally, Zr-doped β-Fe2O3 exhibited very good stability during the process of solar water splitting. These results indicate that by improving its thermal stability, metastable β-Fe2O3 film is a promising photoanode for solar water splitting. 相似文献
55.
论述指向性超低音扬声器阵列的意义和实际应用价值,阐述三种常规超低音扬声器阵列的指向性基本原理,采用专用计算机软件进行模拟仿真,利用实际消声室实验对该基础理论以及计算机仿真结果进行验证及归纳总结;并针对侧墙对Front/Back阵列声辐射的影响进行探究,通过实验得出结论。 相似文献
56.
褪黑素(melatonin,MT)在同步昼夜节律方面具有关键作用,且抑郁症的主要特征就是昼夜节律紊乱导致的睡眠障碍和褪黑素分泌紊乱。针对昼夜节律系统开发出的褪黑素类似物(如阿戈美拉汀、雷美替胺、他司美琼等)在治疗抑郁症方面有积极作用,特别是阿戈美拉汀,这是一种具有抗抑郁和抗焦虑作用的褪黑素受体激动剂及5-HT2C受体拮抗剂。研究综述了昼夜节律紊乱与抑郁症之间的关联,以及褪黑素在运动调控生物节律与改善抑郁行为方面的作用及机制,并提出了运动联合MT的抗抑郁策略。提出运动的抗抑郁作用,一方面通过MT的分泌调节使生物节律同步和MT促进海马神经发生和生物钟基因表达同步,另一方面通过MT调节脑源性神经营养因子节律和水平及改善炎症和氧化应激。 相似文献
57.
高等教育大众化背景下地方高校的办学效益问题 总被引:2,自引:0,他引:2
地方高校由于自身的特殊性,办学效益有一定特性。文章分析地方高校办学效益方面存在的主要问题,指出必须树立效益意识、提高管理水平、强化人才培养、主动融入社会,在高教大众化背景下发展得更充分、更科学。 相似文献
58.
59.
Ben L. Langdown Jack E.T. Wells Sean Graham Matt W. Bridge 《Journal of sports sciences》2019,37(6):656-664
Previous research has highlighted the positive effect that different warm-up protocols have on golf performance (e.g. Sorbie et al., 2016; Tilley & Macfarlane, 2012) with the design of warm-ups and programmes targeting and improving golf performance through the activation and development of specific muscle groups. This study aimed to examine the acute effects of two warm-up protocols on golf drive performance in comparison to a control condition. Using a randomised counterbalanced design over three testing sessions, twenty-three highly skilled golfers completed the control, dynamic and resistance-band warm-up conditions. Following each condition, a GC2 launch monitor was used to record ball velocity and other launch parameters of ten shots hit with the participants’ own driver. A repeated-measures ANOVA found significant increases in ball velocity (ηp2 = .217) between the control and both the dynamic and resistance-band warm-up conditions but no difference between these latter two, and a reduction in launch angle between control and dynamic conditions. The use of either a dynamic stretching or resistance-band warm-up can have acute benefits on ball velocity but golfers should liaise with a PGA Professional golf coach to effectively integrate this into their golf driving performance. 相似文献
60.
Leg amputation side determines performance in curve sprinting: a case study on a Paralympic medalist
Johannes Funken Kai Heinrich Steffen Willwacher Ralf Müller Jonas Böcker Hiroaki Hobara 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(1):75-87
The lower limb kinetics of curve sprinting in amputees are not well described in the literature, particularly with respect to the effect of the side of amputation. This is an issue due to the importance of the knowledge for prosthetic design and classification of athletes. Thus, the aim of this study was to investigate the influence of side of amputation on curve sprinting performance in athletes with a unilateral leg amputation. A three-dimensional motion analysis system (Vicon), four force plates (Kistler) and a modified mathematical human model (ALASKA) were used to compare clockwise and counter clockwise curve sprinting lower limb kinematics and kinetics of a Paralympic medalist with a left-sided knee exarticular amputation. Results reveal that vertical ground reaction force application and total vertical impulse were lower when the affected limb was at the inside of the curve. The unaffected limb showed joint mechanics different to those established for non-amputee athletes and might contribute better to propulsion when being the inside limb. Curve sprinting biomechanics and the ability to attain high radial velocities are directly dependent on the side of amputation relative to the curve direction in a unilateral amputee athlete of highest performance level. 相似文献