共查询到20条相似文献，搜索用时 46 毫秒
1.
2.
本文主要针对铀矿地浸孔成井工艺进行了详细的探讨分析,从钻机定位、钻孔施工、冲孔换浆、下管、冲孔、投砾、注水泥浆及洗井等工艺深入分析其特点,通过不断学习和总结,效益逐年提高,取得了一定的施工经验但是伴随地浸孔机台间竞争的压力越来越大,利润空间越来越小,如何提高钻探的生产效率,降低生产成本,成为钻探行业可持续发展的必要环节. 相似文献
3.
随着采矿技术的迅猛发展与采矿装备的不断更新,锡矿山深部资源的安全高效回采逾来逾依赖于采矿科技的进步。本文阐述了通过改进采矿装备,优化采矿工艺,可大幅提高采矿生产效率和改善井下作业条件,降低工人的劳动强度,进而提高企业经济效益,并具有深远的社会意义。并用发展的眼光提出未来采用计算机模拟采矿工艺的设想。 相似文献
4.
近年来，随着我国经济的增长与国际地位的逐渐提高，我国对各行各业都进行了一定的改进。铣工工艺与技能训练是我国的一个新崛起的行业，大家或许多这方面的内容还不是很了解。然而铣工工艺与技能训练虽然是刚崛起的事业，却得到了国家的重视。因为，该项技术确实能够大大促进我国加工行业的发展，给我国的经济发展带来贡献。目前我国有很多技工学校甚至大学都已经开设了铣工工艺课程。本文将简要的对铣工工艺与技能训练教学创新与实践的相关内容进行探讨，希望大家有所了解。 相似文献
5.
6.
7.
本文所涉及到的工装制造工艺设计管理系统,是在分析计算机辅助工艺设计(CAPP)的研究现状与发展趋势的基础上,根据信息化管理系统的原理和方法,分析、优化工装的工艺设计及管理流程,建立企业级工装数据库,以实现工装数据在企业内共享的目的,提高工艺设计水平、完善技术状态跟踪,实现工装管理与其他业务领域的信息化建设同步、协调发展,全面提升公司综合竞争力. 相似文献
8.
炮采放顶煤工艺是一种重要的煤炭采集工艺的,在我国当前煤炭采集领域占据举足轻重的地位。炮采放顶煤工艺能否得到保持持续稳定的发展速度,关键在于能否有效提高煤炭的采出率和确定合理准确的放煤技术参数。而合理准确的参数确定更是需要切实优化放煤工艺水平。笔者根据自己多年工程实践经验,通过对生产实践的不懈探索,并对结果数据进行严谨的分析对比基础上,提出了一套比较成熟的能够满足当前煤炭开采需要的大倾角炮放工作面悬疑支架放煤技术。 相似文献
9.
本文通过三起较典型的电缆冷缩终端炸裂事故的解剖及理论分析,总结事故原因,提出相应的工艺改善及提高措施,以求提高新制作电缆终端质量,提高电缆抗击过电压能力,延长电缆使用寿命. 相似文献
10.
高新材料运用于比赛器械,极大地推动了体育运动成绩的提高。概括地总结与研究高新材料在体育比赛器械中的作用、相互关系、主要材料与功能和制作工艺特点,有助于加速体育对高新材料的重视和运用。 相似文献
11.
This study examined the effect of carbohydrate ingestion on metabolic and performance-related responses during and after a simulated 1h cycling time trial. Eight trained male cyclists (VO 2 peak = 66.5ml kg -1 min -1 ) rode their own bicycles mounted on a windload simulator to imitate real riding conditions. At a self-selected maximal pace, the cyclists performed two 1h rides (separated by 7 days) and were fed either an 8% carbohydrate or placebo solution. The beverages were administered 25 min before (4.5ml kg -1 ) and at the end (4.5ml kg -1 ) of the ride. With carbohydrate feeding, plasma glucose tended (P = 0.21) to rise before the time trial. Compared with rest, the plasma glucose concentration decreased significantly (P < 0.05) at the end of both rides, with no statistically significant difference being observed between treatments. Thereafter, plasma glucose increased significantly (P < 0.05) at 15 and 30 min into recovery, and was significantly higher at 30 min during the carbohydrate trial compared with the placebo trial. No significant changes in plasma free fatty acids were observed during the ride. However, a significant increase (P < 0.05) in free fatty acids was found at 15 and 30 min into recovery, with no difference between trials. Mean power output was significantly (P < 0.05) greater during the carbohydrate compared with the placebo trial (mean - S.E.: 277-3 and 269-3W, respectively). The greater distance covered in the carbohydrate compared with the placebo trial (41.5-1.06 and 41.0–1.06km, respectively; P < 0.05) was equivalent to a 44s improvement. We conclude that pre-exercise carbohydrate ingestion significantly increases endurance performance in trained cyclists during a 1h simulated time trial. Although the mechanism for this enhancement in performance with carbohydrate ingestion cannot be surmised from the present results, it could be related to a higher rate of carbohydrate oxidation, or to favourable effects of carbohydrate ingestion on the central component of fatigue. 相似文献
12.
Roy J. Shephard 《Journal of sports sciences》2013,31(7):603-620
The biology and medicine of rowing are briefly reviewed. Effort in a 2000 -m race is about 70% aerobic. Because the boat (and in some instances a cox) must be propelled, successful competitors are very tall, with a large lean mass and aerobic power. Large hearts may lead to erroneous diagnoses of a cardiomyopathy. Large respiratory minute volumes must be developed by chest muscles that are also involved in rowing. The vital capacity is typically large, and breathing becomes entrained. Expiration cannot be slowed relative to inspiration (as normally occurs at high rates of ventilation) and the limiting flow velocity may be reached, with the potential for airway collapse. Performance is strongly related to the power output at the ‘anaerobic threshold’, and lactate measures provide a guide to an appropriate intensity of endurance training. Peak blood lactate levels are higher in males (commonly 11–19 mmol·l -1 and occasionally as high as 25 mmol·l -1) than in females (9–11 mmol·l -1), probably because males have a greater muscle mass in relation to blood volume. The skeletal muscles are predominantly slow twitch in type, developing an unusual force and power at low contraction velocities. Many rowers have a suboptimal diet, eating excessive amounts of fat. Lightweight rowers also have problems of weight cycling. Aerobic power and muscle endurance often change by 10% over the season, but such fluctuations can be largely avoided by a well-designed winter training programme. Injuries include back and knee problems, tenosynovitis of the wrist and, since the introduction of large blades, fractures of the costae. 相似文献
13.
许良 《体育科技文献通报》2011,19(2):1-4
基于1985、1995和2005年全国学生体质调研数据,对各时期我国城乡学生形态、机能、体能发展水平进行系统地定量研究,动态分析20年全国城乡学生体质发展的特点与规律。主要研究结果：（1）近20年城乡学生生长发育持续提前,城市学生各项形态指标生长水平高于乡村,身高城乡差距缩小,体重、胸围城乡差距加大;（2）城市学生肺活量水平高于乡村,城乡学生肺活量20年持续下降,前10年乡村学生下降快、后10年城市学生下降快;（3）乡村学生800m、1000m跑水平高于城市,城市女生50m跑、仰卧起坐水平高于乡村,其他素质城乡学生水平波动较大;（4）城市女生50m跑20年持续下降,城乡学生800m和1000m跑、城市学生50m×8往返跑20年加速下降,其他素质20年间有增有降发展极不平稳。 相似文献
14.
采用测量、问卷调查、数理统计等方法,分析定向运动学习前后对大学生身心健康的影响.结果经T检验和x2检验且表明：定向运动不仅能增强学生体质健康水平,而且有助于学生的情绪调节,增强自信心与创新意识,培养勇敢顽强的意志品质,建立良好的人际关系,能有效地促进学生身心健康发展.为了全面提高大学生整体素质,积极实践,构建定向运动课内外一体化教学模式,进行定向运动课程模块化教学,以满足学生的多元化需求. 相似文献
15.
Alan M. Nevill Roger L. Holder Andrew Bardsley Helen Calvert Stephen Jones 《Journal of sports sciences》2013,31(4):437-443
A regression analysis of competitors' tournament results in relation to their world rankings was proposed to identify the effect of home advantage in international ‘grand-slam’ tennis and ‘major’ golf tournaments. The results provided little evidence of home advantage in either the grand-slam tennis or the golf tournaments held in 1993. The only possible evidence of home advantage was found in the Wimbledon tennis and the US Open golf championships. Even these findings can be explained, at least partially, by (1) the availability of information concerning the low world rankings of the British tennis players competing at Wimbledon, and (2) selective entry, allowing only the world's top-ranked foreign golfers into the US open golf tournament. In both cases, the lower ranking home competitors have a greater opportunity to perform above their anticipated world rankings. Therefore, provided entry into tennis and golf tournaments is truly ‘open’ to both the host nation's representatives and foreign competitors alike, home advantage does not appear to be a major factor influencing the competitors' performance in such competitions. These findings may be explained by the relatively objective nature of the scoring systems used in tennis and golf, unlike the subjective influence of refereeing decisions on the results of team-games such as soccer. 相似文献
16.
17.
曲爱宁 《体育科技文献通报》2007,15(8):97-98
柔韧素质是健美操专业学生的专项素质之一,通过对普通高校健美操专业学生分组对照进行柔韧性训练的实验研究,认为对训练肌群辅以按摩器振颤刺激,可大大提高柔韧性训练效果。 相似文献
18.
我国城市体育自然环境建设与发展的研究 总被引：5，自引：0，他引：5
采用实地调查研究、理性思维研究和文献资料调研等方法对主要问题进行了专门研究，提出了进行城市体育场所区域生态功能区划、设计体育生态功能区布局的方案、做好体育场所绿色环境系统规划、制定体育场所生态与绿地管理措施等基本观点，提出了若干城市体育自然环境建设与发展的对策。 相似文献
19.
20.
重新认识体育的社会关联 总被引：3，自引：1，他引：2
体育与政治之间存在一个悖论，体育的发展与经济实力之间没有直线相关，体育与教育部分重叠，体育与宗教最为近缘，体育可借用科学手段，体育的艺术禀性日益明显，体育与养生反映着两种人生观。 相似文献