北京市部分普通高校男篮队员专项身体素质有效成分研究     

刘蓟生  韩旭 《天津体育学院学报》2005,20(5):73-75

对北京市6所普通高校43名男篮队员的专项身体素质进行测评,经因子分析和回归分析等方法筛选出了影响运动训练水平的30m起动跑、助跑摸高、穿梭跑、28m×10折返跑等4个有效因子,并进一步提出了简易综合评定方法,为大学生男篮运动员身体训练水平评定提供了参考依据。  相似文献   

U17足球运动员专项灵敏和耐力素质分析及评价等级的建立     

陈翀  陈效科  王朝信  王启荣 《北京体育大学学报》2016,39(11):112-118

摘要：目的：分析我国优秀U17足球运动员专项灵敏和耐力素质，并建立评价等级标准。主要运用场地测试法、数理统计法，对全国优秀的U17男子足球运动员进行专项灵敏和耐力素质测试和分析，分析结果为：1）按照优良中下差等级划分标准，曲线跑为9.05s以下、9.06~9.40s、9.41~10.20s、10.21~10.70s、10.71s以上；四线往返跑为9.60s以下、9.61~9.90s、9.91~10.60s、10.61~10.90s、10.91s以上。YOYO间歇性耐力跑为3601m以上、3231~3600m、2201~3230m、1951~2200m、1950m以下；2）平均值方面，曲线跑为9.88±0.66s；四线往返跑为10.27±0.53s；YOYO间歇性耐力跑为2754.30±672.37m。得出以下结论：1）足球运动中，曲线跑和四线往返跑是反映专项灵敏的代表性指标，YOYO间歇性耐力跑是反映专项耐力的代表性指标。运用离差法可以客观准确的建立足球运动员专项灵敏和专项耐力评分表和评价等级标准。2）我国U17男子足球运动员的专项灵敏和耐力水平分布比较分散，其位置特征总体表现为专项灵敏素质：前锋>前卫>守门员>后卫；专项耐力素质：前卫>后卫 >前锋>守门员。  相似文献   

DyCl3-KCl和DyCl3-CaCl2体系相图的热力学优化计算     

姚永香  张继红  马芝森  孟祥珍  孙益民  乔芝郁 《上海大学学报(英文版)》2006,10(6):547-552

1 Introduction Molten salts are considered to be used as fluid tar-gets in the nuclear incineration of transuranic elementswith proto accelerators .The molten salts are also usedas the media in high temperature chemical reprocess-ing of spent nuclear fuel of fast reactors .The phase di-agrams of rare earth metal halides in combination withalkali metal halide systems are of pri me i mportance inapplication. The thermodynamic properties and phase diagramsof the DyCl3-MClnsystems ( M =alkali or…  相似文献   

Using a modified argument-driven inquiry to promote elementary school students’ engagement in learning science and argumentation     

Hsiang-Ting Chen  Hsin-Hui Wang  Ying-Yan Lu  Huann-shyang Lin 《International Journal of Science Education》2016,38(2):170-191

This study explored the effects of a modified argument-driven inquiry approach on Grade 4 students’ engagement in learning science and argumentation in Taiwan. The students were recruited as an experimental group (EG, n?=?36) to join a 12-week study, while another 36 Grade 4 students from the same schools were randomly selected to be the comparison group (CG). All participants completed a questionnaire at the beginning and end of this study. In addition, four target students with the highest and the other four students with the lowest pretest engagement in learning science or argumentation to be observed weekly and interviewed following the posttest. Initial results revealed that the EG students’ total engagement in learning science and argumentation and the claim and warrant components were significantly higher than the CG students. In addition, the EG students’ anxiety in learning science significantly decreased during the study; and their posttest total engagement in learning science scores were positively associated with their argumentation scores. Interview and observation results were consistent with the quantitative findings. Instructional implications and research recommendations are discussed.  相似文献   

甲基纤维素修饰电极对H2O2电催化还原的研究     

李业梅  戴月 《郧阳师范高等专科学校学报》2004,24(6):18-20

用甲基纤维素(MC)将过氧化氢酶(Cat)固载于热裂解石墨电极表面,制备了Cat-MC膜修饰电极.甲基纤维素膜中的过氧化氢酶与电极直接传递电子.在pH6.0的磷酸盐缓冲溶液中可得到一对可逆的过氧化氢酶辅基血红素Fe(III)/Fe(II)电对氧化还原峰,式电势为-0.331V(vsSCE).其式电势随溶液的pH值增加而负移且成线性关系,直线斜率为-38.0mV/pH,说明过氧化氢酶的电子传递过程伴随有质子的转移.并研究了过氧化氢酶修饰电极对H2O2的电催化性能.在H2O2一定浓度范围(15.6～110.1μmol/L)内,催化电流与H2O2浓度成线性关系.  相似文献   

5-溴水杨醛甘氨酸修饰碳糊电极测定微量Cu2+的研究     

匡云飞  邹建陵  李薇  杨颖群 《衡阳师范学院学报》2006,27(6):44-46

在pH=9.0 H3BO3-Na2B4O7缓冲体系中,以5-溴水杨醛甘氨酸修饰碳糊电极为工作电极,Cu2 于 120mV(vs.SCE)处产生一灵敏的吸附波,其二阶导数峰电流与Cu2 浓度在4.0×10-9~8.0×10-7mol.dm-3范围内呈良好的线性关系,相关系数为0.9964,检出限为6.0×10-10mol.dm-3(3倍信噪比)。应用该法测定发样中Cu2 的含量,结果令人满意。  相似文献   

纳米碳—PVC膜修饰电极测定镉     

黎江鹏  胡小安  王浩华  罗永刚 《楚雄师范学院学报》2007,22(3):52-54,59

介绍了用纳米碳-PVC膜修饰电极测定痕量镉的新方法。优化了各种试验条件,如支持电解质的选择、pH值的影响、修饰剂的用量、富集电位及时间、扫描速率等。  相似文献   

Agile administrative choreographies for multimode education at the University of Pretoria     

Tony John Mays  Folake Ruth Aluko 《Distance Education》2019,40(1):5-19

This paper responds in part to a special edition of this journal (39/2) on dual-mode provision. We were concerned that contact providers might drift into distance education provision through extending campus-based online learning without first thinking through the underpinning implications of its administrative systems, an issue that was not addressed in the special edition. Proceeding from a pragmatic and constructivist perspective, while adopting a transactional orientation drawing on systems theory and hermeneutics, this paper focuses on the challenge for administrative staff and systems of the changing nature of provision in terms of both the underpinning learning and business models. Based on experience and reflection, we conclude that the move into dual- and multimode provision is inevitable and that this requires agility on the part of both administrative staff and systems that is often overlooked in planning and review processes.  相似文献   

修正的Bernstein-Durrmeyer算子的若干保持性质     

马月梅 《石家庄学院学报》2005,7(3):14-16

修正的Bernstein-Durrmeyer算子既具有一些与Bernstein算子相似的性质，同时也具有Bernstein-Durrmeyer算子的一些性质，研究了修正的Bernstein-Durrmeyer算子的特性，得到相应原函数的单调性、凸性、H^n类的保持性质，所得结果类似于所对应的Bernstein算子的结果。  相似文献   

转基因生物对生物多样性的影响     

毛新志  冯巍 《科学学研究》2006,24(1):22-25

生物多样性是生态平衡的基础。转基因生物是强势生物,其对生物的诸多影响主要表现在:对非目标生物的伤害,基因污染破坏生物多样性,对传统物种的威胁和单一转基因生物种植或饲养的危险。“和而不同”为我们维护生物多样性提供了哲学依据。我们应该重视转基因生物对生物多样性的影响,保护生物多样性,维护生态平衡,促进人与自然的可持续发展。  相似文献