贵阳花溪地区早三叠世碳、氧同位素特征及其古环境意义     

尚晓冬  时国  韦恒叶 《中国科学院研究生院学报》2015,32(3):363-372

对取自贵阳花溪地区改毛剖面上二叠统一下三叠统碳酸盐岩样品进行碳、氧同位素测定,利用所测数据建立相应的演化曲线.根据曲线变化情况,结合地质背景与岩性,着重探讨碳同位素变化的环境原因,并对研究区该时期古环境进行分析解释.研究表明,早三叠世初期,该地区海洋生态环境遭到严重破坏,但在Griesbachian早期有一次短暂恢复,而后又进入长期低迷的缺氧环境直到Smithian中期.  相似文献   

Temporal specificity of training: intra-day effects on biochemical responses and Olympic-Weightlifting performances     

Achraf Ammar  Hamdi Chtourou  Khaled Trabelsi  Johnny Padulo  Mouna Turki  Kais El Abed 《Journal of sports sciences》2015,33(4):358-368

The aim of this study was to investigate the performance of an Olympic-Weightlifting session training at three times of the day on the performance related to biochemical responses. Nine weightlifters (21 ± 0.5 years) performed, in randomised order, on three Olympic-Weightlifting training (snatch, clean and jerk) sessions (08:00 a.m., 02:00 p. m., 06:00 p. m.). Blood samples were collected: before, 3 min and 48 h after each training session. Haematological parameters and markers of muscle injury were assessed. Resting oral temperature and rating of perceived exertion (RPE) were also assessed during each session. ANOVA showed that the performance was better (P < 0.001) at 02:00 p. m. with a less RPE (P < 0.01) compared to the morning and the evening sessions while there was higher (P < 0.05) oral temperature at 06:00 p. m. versus 08:00 a.m. and 02:00 p. m. Muscle damage changed immediately (without significant effect after 48 h) after the training sessions with lower values ??in the evening compared to the morning. In conclusion, the afternoon training is more effective than morning or evening sessions for weightlifters. Therefore, coaches and weightlifters should be advised to schedule their training session in the afternoon hour.  相似文献   

校园空气负氧离子浓度分布与空气质量评价     

叶宏萌  郑茂钟  姜嘉祺  谢行冬 《鸡西大学学报》2015,(4):153-156

空气负氧离子浓度水平不仅反映了空气质量,还直接影响人们的舒适程度和健康状况。研究武夷学院空气负氧离子浓度含量发现,其受人类活动力度、海拔高度、空气流通状况、动态水体和植被分布等综合因素影响,并具有明显的气象变化和日变化特征。负氧离子浓度含量排序为:暴雨天>小雨天>雨后阴天>晴天;一日中上午>傍晚>中午。测量结果表明该校园整体空气质量等级达到四级或者三级,空气清新,有利于师生健康。  相似文献   

MTL代数中素滤子集上的拓扑     

赵晓东  张家录 《湘南学院学报》2011,32(2):15-18

通过研究MTL代数M中滤子、极大滤子的性质,在M的全体素滤子集P(M)上引进拓扑T并研究拓扑空间(P(M),T)的紧致性、分离性、连通性等拓扑性质,证明了(P(M),T)是紧致的T0空间.如果把P(M)上拓扑T限制在M的全体极大滤子集M(M)上,则(M(M),TIM(M)是紧致的Hausdorff空间.  相似文献   

Extraterrestrial artificial photosynthetic materials for in-situ resource utilization     

Liuqing Yang  Ce Zhang  Xiwen Yu  Yingfang Yao  Zhaosheng Li  Congping Wu  Wei Yao  Zhigang Zou 《国家科学评论(英文版)》2021,8(8)

Aerospace milestones in human history, including returning to the moon and manned Martian missions, have been implemented in recent years. Space exploration has become one of the global common goals, and to ensure the survival and development of human beings in the extraterrestrial extreme environment has been becoming the basic ability and technology of manned space exploration. For the purpose of fulfilling the goal of extraterrestrial survival, researchers in Nanjing University and the China Academy of Space Technology proposed extraterrestrial artificial photosynthesis (EAP) technology. By simulating the natural photosynthesis of green plants on the Earth, EAP converts CO₂/H₂O into fuel and O₂ in an in-situ, accelerated and controllable manner by using waste CO₂ in the confined space of spacecraft, or abundant CO₂ resources in extraterrestrial celestial environments, e.g. Mars. Thus, the material loading of manned spacecraft can be greatly reduced to support affordable and sustainable deep space exploration. In this paper, EAP technology is compared with existing methods of converting CO₂/H₂O into fuel and O₂ in the aerospace field, especially the Sabatier method and Bosch reduction method. The research progress of possible EAP materials for in-situ utilization of extraterrestrial resources are also discussed in depth. Finally, this review lists the challenges that the EAP process may encounter, which need to be focused on for future implementation and application. We expect to deepen the understanding of artificial photosynthetic materials and technologies, and aim to strongly support the development of manned spaceflight.  相似文献   

水中化学需氧量检测方法的比对分析     

詹为民  沈兆欣  张静林  朱振 《中国科技纵横》2014,(10):77-78

通过重铬酸钾法（经典潮与快速消解分光光度法（改进后的快速潮两种试验方法对不同水样化学需氧量的对比分析,确定两种方法对不同水样比对结果,最大差值7mg/L,加标回收率为93．5％-105％。改进后的快速法标准样品验证试验分析实验结果准确度与精密度在方法控制范围内。证明改进后的快速法操作简便,方法稳定,精密度与准确度较高,与经典法比对可比性好。  相似文献   

Changes in repeated-sprint performance in relation to change in locomotor profile in highly-trained young soccer players     

Martin Buchheit  Alberto Mendez-Villanueva 《Journal of sports sciences》2014,32(13):1309-1317

Abstract

The aim of this study was to examine the effects of changes in maximal aerobic (MAS) and sprinting (MSS) speeds and the anaerobic reserve (ASR) on repeated-sprint performance. Two hundred and seventy highly-trained soccer players (14.5 ± 1.6 year) completed three times per season (over 5 years) a maximal incremental running test to approach MAS, a 40-m sprint with 10-m splits to assess MSS and a repeated-sprint test (10 × 30-m sprints), where best (RSb) and mean (RSm) sprint times, and percentage of speed decrement (%Dec) were calculated. ASR was calculated as MSS-MAS. While ?RSb were related to ?MSS and ?body mass (r² = 0.42, 90%CL[0.34;0.49] for the overall multiple regression, n = 334), ?RSm was also correlated with ?MAS and ?sum of 7 skinfolds (r² = 0.43 [0.35;0.50], n = 334). There was a small and positive association between ?%Dec and ?MAS (r² = 0.02 [?0.07;0.11], n = 334). Substantial ?MSS and ?MAS had a predictive value of 70 and 55% for ?RSm, respectively. Finally, ?ASR per se was not predictive of ?RSm (Cohen’s = +0.8 to ?0.3 with increased ASR), but the greater magnitude of ?RSm improvement was observed when MSS, MAS and ASR increased together (0.8 vs. +0.4 with ASR increased vs. not, additionally to MSS and MAS). Low-cost field tests aimed at assessing maximal sprinting and aerobic speeds can be used to monitor ?RS performance.  相似文献   

心力变化趋势与摄氧量和心率相关性的研究   总被引：6，自引：0，他引：6  

步斌  苏全生  孙君志  周薇  龙小安 《体育科学》2004,24(10):35-37

20名运动员及15名普通大学生志愿受试者在功率自行车上做递增负荷运动直至疲劳。用运动心力监测仪在记录受试者运动每个阶段的第一心音幅值，把它相对于安静时幅值增加的相应倍数定义为心力变化趋势(Cardiac Contractility Change Trend，CCCT)，并用运动心肺功能仪同时记录其摄氧量和心率，探讨运动员及普通大学生在运动及恢复状态下心肌收缩力变化趋势与摄氧量和心率的相关性。结果表明，受试者在运动及恢复阶段的心肌收缩力与摄氧量(r=0．589～0．978)和心率(r=0．739～0．986)的变化趋势之间存在着高度相关。提示，心力变化趋势指标可以作为运动员和常人临床测定心肺功能的重要指标之一，为运动医学和临床实践提供依据。  相似文献   

运动中肌肉氧含量下降与肌肉疲劳的关系     

李秀荣  王景贵  张立 《武汉体育学院学报》2004,38(2):63-64,68

肌肉的强烈收缩将导致疲劳，肌肉在疲劳状态下工作能力下降，并容易导致损伤，因而能否有效评价疲劳对监控运动负荷以及避免肌肉损伤具有重要意义。肌电指标是传统的评定肌肉疲劳的方法，在训练状态下不易获得，近红外光谱技术是一种无损的可以遥测组织氧含量的方法，由于氧含量下降可能与肌肉疲劳的发生相关，因而监测肌氧含量的下降程度可能是评定肌肉疲劳的新方法。  相似文献   

最大吸氧量对青少年100m和800m训练项目的影响     

程磊  陈霞 《山西师大体育学院学报》2005,20(Z1):122-124

采用文献资料法、实验法、数理统计法对某重点中学体育训练队的16名男女学生进行Pwc170台阶实验测试分别推算出各受试学生的Vo2m ax,然后对男女各组100m和800m进行相关性分析,根据测试结果及分析显示,Vo2m ax对男生100m与800m成绩的线性关系达到了显著水平,男女生存在差异。对青少年的最大吸氧量的预测有非常重要的意义。  相似文献