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一、短跑的特征
现代短跑运动最核心的东西就是以髋为轴的高速摆动一平动运动，以及在高速跑动中的放松技能。传统的短跑理论强调后蹬，破坏了用力的连续性，会使身体重心轨迹波动较大，降低了整体运动的效果，影响运动成绩。 相似文献
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通过对影响有氧能力因素的理论分析、结合当前少年中跑运动员的训练现状,指出发展有氧能力对少年中跑运动员运动能力的重要性,并就发展中跑运动员有氧能力的训练方法,提出训练建议,供训练界同仁参考。 相似文献
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The batch extractive distillation (BED) process has the advantages of both batch and extractive distillation. It is one of the most promising means for the separation of azeotropic and close-boiling point systems. However, so far this process has not been applied in industry due to its over-complexity. A new shortcut model was proposed to simulate the operation of the batch extractive distillation operations. This algorithm is based on the assumption that the batch extractive distillation column can be considered as a continuous extractive distillation column with changing feed at any time. Namely, the whole batch process is simulated as a succession of a finite number of steady states of short duration, in which holdup is considered as constant mole. For each period of time the batch extractive distillation process is solved through the algorithm for continuous extractive distillation. Finally, the practical implementation of the shortcut model is discussed and data from the laboratory and literature are presented. It is found that this model has better adaptability, more satisfactory accuracy and less calculative load than previous rigorous model. Hence the algorithm for simulating BED is verified. 相似文献
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The reaction kinetics of dilute acetic acid with methanol using NKC-9 as catalyst was studied at temperatures of 308 K, 318 K, 323 K, 328 K. The kinetic model based on Langmuir-Hinshel-wood rate model was derived and the activation energy was 6.13×104 kJ/kmol. The experiment of recovery of dilute acetic acid was conducted in a packed bed catalytic distillation column. The optimal process parameters and operational conditions determined to make up to 85.9% conversion of acetic acid are as follows:the height of catalyst bed is 1 100 mm, reflux ratio is 4:1, and the ratio of methanol to acetic acid is 2:1. The method can be used as a guide in industrial scale recovery of 15%-30% dilute acetic acid. 相似文献
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A volume-based method for measuring particle-size distribution (PSD) fractal dimensions of porous mediums was developed by employing laser size-analyzing technology. Compared with conventional approaches of using hydrometer or screen to determine PSD, this method can avoid calculation errors and measure smaller size-scale porous medium. In this paper the experimental porous mediums were brown soil, kaolin and sand soil. A micro-order of magnitude ( 10 ^-5 m) in particle-size interval could be shown in PSD results of brown soiland kaolin. The experiments indicated that brown soil had a nearly mono-fractal PSD character, while kaolinand sand soil showed multi-fractal PSD characters. By the adsorption isotherm experiments, the PSD fractal dimensions of the sand soil were also found to keep a linearly increasing relation with the linear adsorptive parameters of the soils in different intervals to adsorb benzene from aqueous solution. 相似文献
6.
徐世民 《佳木斯教育学院学报》2012,(3):18+20
近代哲学为解决自身危机大力引进自然科学方法,造成内部理性主义与经验主义的分裂。而自然科学却排斥哲学的存在并要将世界统一到完整的机械世界图景当中。哲学和科学的近代冲突终于导致了三个方面的危机和问题,而马克思的思想探索之路深受此背景的影响,他必须克服和超越。历史唯物主义对旧社会科学三种形态进行了超越,从而给予马克思主义以牢固的科学性。 相似文献
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徐世民 《沙洋师范高等专科学校学报》2012,13(3):62-64
文章戒繁冗,尚精炼,自古以来如此。具有现代公文性质的古代奏议尤当如此,而包拯正是这方面无可争议的代表。无论从其奏议的篇幅、修辞还是内容来看,其朴实严谨精炼的文风和求真务实的论事,都不失其作为具有现代公文性质的代表。 相似文献
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徐世民 《黎明职业大学学报》2012,(2):15-17
摘要：通观王安石的政论文章,其人才思想中有3个突出的矛盾点：即多才与少才,用才与留不才。先变法后人才和先人才后变法。这其中既显示了王安石的人格与思想特色,也反应了他思想上的无奈和部分失误。 相似文献
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徐世民 《安徽广播电视大学学报》2012,(3):16-19
柏格森哲学的"直觉",不是从外部肢解分析对象的碎片,而是深入事物的内部去经验整体,克服科学理智对变化的事物几何化、静止化抽象的缺陷。理智要当物质的主人,只能导向功利性的工具理性思维。人类语言与理智特征上的相似,也是将理智缺陷放大并导致形而上学混乱的原因。在传统的价值理性框架内,理智的缺陷和工具理性的滥用都无法得到有力的克服,柏格森的哲学则指引了另一条道路。 相似文献