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1.
Zhong Shao Xiang 《大连大学学报》1995,(4)
根据叶片绕流理论,用保角变换和级数展开的方法推导出由变换系数表示的叶片表面的速度分布,给出了轴流泵可调叶片的水动力矩数学模型及可靠性分析。最后,对某泵可调叶片的水动力矩进行了计算。研究表明,方法是可靠的,结果令人满意。 相似文献
2.
为了研究不同频率的激振力叠加作用下平板叶片的位移响应变化,在平板叶片上选取激励点和多个响应点进行相关性激励试验。试验中,首先运用设计的加法器对频率为112、280和583 Hz的简谐力分别进行叠加,然后以压电陶瓷片作为激振器对平板叶片进行激励,同时以压电陶瓷片作为感应器采集位移响应,最后应用谱分析方法对位移响应进行分析。通过对比不同频率的激振力叠加作用下的位移响应自功率谱幅值,发现自功率谱幅值比单一频率激振力作用时有所降低,并且降低的程度和与其叠加的激振力频率的大小和个数有关,叠加的个数越多,降低的程度越大。 相似文献
3.
矮牵牛在生产中常采用播种繁殖。但是种子大都是从国外进口的,价格昂贵,为了更快的获得大量种苗,通过对矮牵牛进行了快速繁殖方法的实验．主要采用组织培养技术繁殖．经半年多的研究和配方试验,掌握了矮牵牛的组织培养配方及技术,大大缩短了其繁殖周期．并保持其品种的稳定性． 相似文献
4.
为解决航空发动机空心涡轮叶片陶瓷型芯的3D打印难题,研究基于图像投影的复杂结构陶瓷型芯光固化成型（mask-image projection stereolithography,MIP-SLA）方法。搭建MIP-SLA工艺系统平台,对陶瓷浆料的制备和打印工艺参数的配置进行研究。分析利用球磨机将光敏树脂和陶瓷颗粒进行混合制备陶瓷浆料时,光敏树脂类型、固相含量、陶瓷颗粒粒径、分散剂含量和球磨时间对陶瓷浆料性能的影响。对不同配置参数下的打印效果进行对比分析,对确定的最佳打印工艺参数进行打印效果验证。 相似文献
5.
Eric Sprigings Peter McNair Grant Mawston David Sumner Mark Boocock 《Sports Engineering》2006,9(3):147-153
The intent of this project was to explore the feasibility of personalising the paddle blade size for individual flatwater
kayakers based on their power output profiles. Twelve elite male kayakers performed on a kayak ergometer at the same intensity
and resistance that they would normally experience while paddling at race pace for 500 m on the water. The kayak ergometer
was instrumented so that power profiles could be determined from the instantaneous force and velocity of the representative
centre point of the paddle blade. From the power profile information, the researchers calculated a personalised blade size
that was expected to improve performance for those kayakers differing more than 5% from the calculated ‘ideal’ size. For the
elite kayakers studied, it was recommended that seven of the paddlers should increase their blade size by approximately 5–10%.
For the remaining five paddlers, the results indicated that their current blade sizes were within the expected measurement
error of their predicted ideal value and should be retained. It is anticipated that this research will provide the theoretical
rationale for elite kayakers to see the need to personalise their blade size based on their own muscle power profiles. 相似文献
6.
金属研磨平板消除冰刀卷刃的实验研究 总被引：3，自引：1，他引：2
研究目的：通过剖析传统研磨冰刀出现卷刃的原因及消除卷刃过程中存在的问题，寻求解决该问题的途径。研究方法：借鉴工业生产中金属研磨平板精研磨理论与实践，运用比较的方法，找出油石研磨冰刀存在的卷刃问题，确定出解决该问题的实验方案。主要结果和结论：设计制造出速滑刀金属研磨平板、勾刃冰刀金属研磨棒。通过实验证明，运用该方法、研磨冰刀刃间面可直接切断卷刃，获得良好的锋刃及滑度，取代传统油石研磨卷刃做法具有可行性。 相似文献
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8.
防爆局扇是我总厂新开发的高效率、低能耗的新型井下通风设备。其铸铝扇叶要求精度高，尺寸公差小。叶片为流线型，按坐标定位，最小壁厚尺寸为0.62mm，国内无生产成功先例。我们经过分析研究和多次试验采用了数控切割样板，水玻璃砂造型，分体组芯，表面涂滑石粉，提高浇注温度，去气精炼和变质处理等方法，解决了该件所存在的技术难题。并试制出合格的产品。 相似文献
9.
本文主要介绍用工具显微镜、扫描电镜、冷光源照相机等仪器对TiN YT15涂层刀具与未涂层刀具的磨损形态进行观察与分析,发现涂层刀具的主要失效形式,进一步分析了涂层刀具使用寿命高的机理。 相似文献
10.
Based on the nonlinear continuum damage model(CDM) developed by Chaboche,a modified model for high cycle fatigue of TC4 alloy was proposed.Unsymmetrical cycle fatigue tests were conducted on rod specimens at room temperature.Then the material parameters needed in the CDM were obtained by the fatigue tests,and the stress distribution of the specimen was calculated by FE method.Compared with the linear damage model(LDM),the damage results and the life prediction of the CDM show a better agreement with the test and they are more precise than the LDM.By applying the CDM developed in this study to the life prediction of aeroengine blades,it is concluded that the root is the most dangerous region of the whole blade and the shortest life is 58 211 cycles.Finally,the Cox proportional hazard model of survival analysis was applied to the analysis of the fatigue reliability.The Cox model takes the covariates into consideration,which include diameter,weight,mean stress and tensile strength.The result shows that the mean stress is the only factor that accelerates the fracture process. 相似文献