Superior performance and high service stability for GeTe-based thermoelectric compounds     

Tong Xing  Qingfeng Song  Pengfei Qiu  Qihao Zhang  Xugui Xia  Jincheng Liao  Ruiheng Liu  Hui Huang  Jiong Yang  Shengqiang Bai  Dudi Ren  Xun Shi  Lidong Chen 《国家科学评论(英文版)》2019,6(5):944

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Postural balance and rifle stability in a standing shooting position after specific physical effort in biathletes     

Dorota Sadowska  Justyna Krzepota  Andrzej Klusiewicz 《Journal of sports sciences》2019,37(16):1892-1898

The aim of the study was to evaluate the effect of maximal specific physical effort on postural balance and rifle stability in biathletes in a standing shooting position. The study included 10 junior elite biathletes. The measurements were taken with the Vicon system and AMTI force platform. Postural balance and rifle stability characteristics were determined at rest as well as 1 and 5 min post maximal specific physical effort which was performed on a ski ergometer and continued until exhaustion. Maximal physical effort exerted a significant effect on all examined postural sway and rifle sway characteristics. The duration of the post-exercise changes was longer than 5 minutes. Higher post-effort rifle sway was observed in the vertical direction than in the across the shooting line direction. Post-effort postural balance impairment in the shooting line was much greater than in the across the shooting line direction. Moreover, a strong correlation was found between postural balance and rifle stability. Maximal physical effort influenced postural balance and rifle stability during aiming. Rifle sway during aiming in a standing shooting position seems to be coordinated with the postural sway of the biathlete’s body. Thus, an increase in postural sway contributes to greater sway and lesser stability of the rifle.  相似文献   

石膏/蚯蚓粪肥对赤泥团聚体结构稳定性的影响     

王琼丽  叶羽真  薛生国  江钧  朱锋  田桃 《中国科学院大学学报》2019,36(4):530-536

赤泥是氧化铝工业生产过程中排放的高碱性固体废弃物，迄今尚无经济有效的处置方法。以华中地区某堆场赤泥为研究对象，通过土培实验研究改良剂（石膏、蚯蚓粪肥、石膏+蚯蚓粪肥）对赤泥团聚体稳定性的影响。结果表明：石膏的添加能显著降低赤泥pH，而蚯蚓粪肥能显著增加赤泥有机碳含量。土培60 d时，石膏添加后赤泥pH由10.54降到8.75，蚯蚓粪肥添加后赤泥有机碳含量由3.54 g·kg^-1增加至14.31 g·kg^-1。土培180 d时，石膏、蚯蚓粪肥、石膏+蚯蚓粪肥添加后赤泥水稳性团聚体含量由12.04%分别增加到23.49%、29.24%、33.94%；团聚体平均重量直径由0.15 mm分别增加到0.26、0.30、0.34 mm；可蚀性因子由0.36分别降低到0.31、0.30、0.29。石膏和蚯蚓粪肥的添加促进水稳性团聚体形成，提高赤泥团聚体稳定性。基质改良对赤泥团聚体稳定性的影响效果依次为：石膏+蚯蚓粪肥 > 蚯蚓粪肥 > 石膏。研究结果对赤泥土壤化处置和规模化消纳研究有科学参考意义。  相似文献   

Does local dynamic stability of kayak paddling technique affect the sports performance? A pilot study     

Daniel Hamacher  Tobias Krebs  Guido Meyer  Astrid Zech 《European Journal of Sport Science》2018,18(4):491-496

During competition, kayak athletes must optimally adapt to environmental factors (e.g. wind, waves) to achieve peak performance. However, the ability to adapt to such perturbations has never been assessed in kayak paddling. Therefore, the aim of the current study was to evaluate the local dynamic stability in sports technique of youth sprint kayak athletes. In a cross-sectional study, 14 healthy male athletes were recruited from an elite youth sprint kayak squad. During an incremental kayak ergometer test, mean power, heart rates and local dynamic technique stability of hands, arms, trunk and paddle were registered and the association with the athletes 2000?m free-water times were estimated using mixed models. The 2000?m free-water performance significantly predicted the paddles (p?=?.037) local dynamic stability whereas no association was found for the trunk or the upper extremity kinematics. In conclusion, kayak athletes with high-performance capability over 2000?m paddling depict high local dynamic technique stability. This emphasizes the importance of a stable technique for advanced kayak skills, especially regarding paddling movements.  相似文献   

Protective Factors as Predictors of Suicide Risk Among Graduate Students          下载免费PDF全文

Kristin L. Bruns  Amber Letcher 《Journal of College Counseling》2018,21(2):111-124

The purpose of this study was to examine protective factors as predictors of suicide risk among graduate students (n = 413) at a large midwestern university. Using binary logistic regression, the authors assigned students to risk classifications (i.e., nonrisk group or suicide risk group). Results indicated emotional stability as the strongest predictor for participants’ placement into the nonrisk or suicide risk group. The authors discuss implications for counselors and directors of college counseling centers, as well as directions for future research.  相似文献   

不同权力结构下考虑搭便车行为的闭环供应链决策研究          下载免费PDF全文

李新然  刘媛媛  俞明南 《科研管理》2018,39(3):45-58

本文针对单个制造商和零售商组成的闭环供应链系统,基于博弈论的基本方法,分别构建了集中式、制造商领导的Stackelberg博弈、零售商领导的Stackelberg博弈、制造商和零售商存在Nash均衡博弈等模式下的闭环供应链决策模型,进而对比分析消费者搭便车行为对不同权力结构闭环供应链的决策及利润等影响问题。研究表明,集中式决策闭环供应链的总利润和分散式决策中各权力主体的利润受到搭便车系数的影响;各权力结构下网络直销渠道的销售价格和市场需求均随搭便车系数的增加而增加等。  相似文献   

电力系统电压稳定性的研究     

卢文波 《黑龙江科技信息》2007,(4S):31-31,135

对国内外电压稳定问题研究的现状进行了概述。特别介绍了对电压失稳机理的认识以及当前广泛采用的几种电压稳定性的分析方法，而且还介绍了电压稳定研究进一步发展的方向。  相似文献   

Boundary control of a linear distributed parameter bioprocess     

Hideki Sano 《Journal of The Franklin Institute》2003,340(5):293-306

This paper is concerned with boundary control of a linear distributed parameter bioprocess. Huang's result (Ann. Differential Equations 1(1) (1985) 43) on the spectrum determined growth assumption is applied to prove that the closed-loop system becomes exponentially stable under a certain condition with respect to the feedback gain. Moreover, it is shown that the decay rate of the open-loop system is given by letting the feedback gain tend to zero.  相似文献   

卵磷脂稳定性的研究进展     

许海丹  吕秀阳  李英华 《科技通报》2006,22(2):267-270

在卵磷脂结构和性质介绍的基础上,综述了来源、贮存方式和生产工艺等对卵磷脂稳定性影响的研究现状与进展,并对提高卵磷脂稳定性的途径进行了阐述和展望。  相似文献   

金融稳定评估指标体系:银行稳定的宏观成本控制研究     

王明华  黎志成 《中国软科学》2005,45(9):126-132

区域性金融稳定评估指标体系是金融风险预警系统的一种,它是通过考察区域内宏观经济和金融机构的发展状况,在把相关数据汇总的基础上,进行审慎分析后得出的关于风险提示及其变动趋势的信息分析系统。本文以我国湖北省为例,从建立指标体系的理论基础、目标要求、指标体系构成、分析方法以及进一步完善指标体系需要解决的问题五个方面入手,阐述了建立区域性金融稳定评估指标体系的原则和内容。  相似文献