660MW发电机励磁小轴联轴器断裂原因分析

通过宏观检查、光谱分析、力学性能试验、显微组织及断口分析等手段，对发电机励磁小轴联轴器的断裂原因进行了分析。结果表明：裂纹起源于联轴器一侧的引线槽底部边缘转角处，表现为穿晶特征，断口存在明显的疲劳辉纹，为典型的疲劳开裂；引线槽底部转角部位的加工不符合要求，没有进行圆角过渡所导致的应力集中，是造成发电机励磁小轴联轴器出现疲劳裂纹的主要原因。     

足球机器人比赛中的一种位置滤波方法

在机器人足球比赛中,小球的位置的准确获得和未来的位置的预测对于机器人动作完成成功与否非常重要。本文通过对小球在场上的运动特性和实际采集点的位置分布特性的分析,提供了一种基于卡尔曼滤波的小球位置估计和预测的方法,并给出了实施方法和实验结果。     

QD24桥式堆包机简介及其检修方法

本文向大家介绍二下新厂区的QD24桥式堆包机。并提出了相关的检修要求。     

Study on energy threshold and spectral characteristics with spot radius based on LIBS technology

The aim of this study is to investigate the relationship between the laser-induced optical breakdown energy threshold and the spectral signal changes with the spot radius. First of all, using the avalanche breakdown threshold theory calculates the threshold avalanche ionization rate ηc. Combining with the theory of light intensity distribution and the relationship between pulse energy and peak power, numerical calculations have obtained the law of change of spot radius and threshold laser energy. Secondly, the variation of the spectral signal-to-noise ratio (SNR) with the laser energy is measured according the experimental measurement, and the threshold laser energy required for optical breakdown at different spot radius is obtained. The theoretical threshold model of the relationship between the threshold laser energy and the quadratic function of the spot radius obtained by numerical calculation is verified, and it is revised, the results show that the relative error between the revised theoretical threshold model and the experimental threshold model is less than 5.3%. At last, the influence of the spot radius on the spectral signal and electron density is also analyzed, it is found that both the spectral intensity and the electron density have a maximum at the spot radius of 11 μm. The results show that it is necessary to find the best spot radius during the laser induced breakdown spectroscopy (LIBS) experiment. This provides a reliable theoretical basis and experimental reference for further study of the influence of spot radius on LIBS technology measurement.     

基于背景扣除法消除土壤基底中Al元素干扰的LIBS实验研究

土壤中重金属的污染严重影响了农业和食品安全，因此，对重金属污染的高效、准确的检测是目前亟需解决的问题。采用激光诱导击穿光谱技术（Laser induced breakdown spectroscopy，LIBS）对土壤中Ni元素进行定量分析时发现，土壤中波长为373.68 nm的Ni元素的特征峰会受到Al元素在373.39 nm处谱线的影响，因此，将纯铝基底土壤光谱与压片土壤光谱进行了对比测量。提出了以纯Al作为基底，采用纯Al基底谱线扣除土壤背景中Al元素谱线的方法，来消除土壤背景中Al元素对Ni元素干扰，该方法被称为背景扣除法。实验确定了两种土壤样品的最佳延迟时间均为1.0 μs，透镜到样品的距离（Lens to sample distance，LTSD）分别为97 mm和96 mm。采用内标法对两种土壤样品中的Ni进行了定量分析，得到纯Al基底土壤样品中Ni元素的定标曲线拟合效果较好，相关系数R2为0.997，最大标准偏差（Relative standard deviation，RSD）为4.34%，采用基底背景扣除法后的纯铝基底土壤样品中Ni元素检测的相对误差降低到4%。实验结果表明:采用LIBS技术对土壤中重金属元素含量测量时，在元素特征谱线有限的情况下，为避免谱线干扰，提高检测精度，采用背景扣除的方法能够有效消除元素间的谱线的干扰。     

秦山核电二期辅助变投运的问题和建议

秦山核电二期220 kV辅助变投运过程中,暴露出一些问题:冲击受电时,接地故障信号误发,压力释放保护经常误报警等.文章对上述问题进行了分析和探讨,并提出了一些建议.     

Plasma characteristics and quantitative analysis of Pb and Ni in soil based on LIBS technology

When measured by laser induced breakdown spectroscopy, the characteristic parameters of the plasma fluctuate significantly with the experimental parameters, which would have a greater impact on the quantitative measurement. The effects of two experimental parameters, lens to sample distance(LTSD) and delay time, on plasma temperature and electron density were analyzed. Thereafter the optimal LTSD and delay time for quantitative analysis of Pb and Ni in soil were identified. Two element calibration curves were calculated by the internal standard method under the optimal LTSD and delay time. About the two elements, correlation coefficient of the calibration curves is above 0.993. The maximum relative standard deviation(RSD) were 4.47% and 4.76%, respectively, and the maximum relative errors were 12% and 4.8%, respectively. The experimental results showed that laser induced breakdown spectroscopy method in combination with plasma characteristic parameter analysis shows the advantage on quantitative analysis of heavy metals in soil.     

梨幼果多酚的纯化及其抗氧化性

采用5种大孔吸附树脂分离纯化梨幼果多酚,并测定其抗氧化性。结果表明,综合分析吸附与解吸效果,NKA-9大孔树脂性能较好,最适合用来纯化梨幼果多酚;NKA-9大孔树脂对梨幼果多酚进行纯化时,最适宜的条件为:将2 mg/m L的多酚提取液调至p H值为5.0,设定进样流速为1 m L/min,充分吸附,然后用70%的乙醇为洗脱液进行动态洗脱,洗脱流速为1 m L/min,用此方法纯化后的梨幼果多酚的纯度从6.23%提高到30.68%;梨幼果多酚粗品对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl radicals,DPPH)自由基、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐自由基(2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate)radicals,ABTS~+·)、亚硝酸基的IC50值分别为:151.07、152.48、490.35μg/m L;梨幼果多酚纯品对DPPH自由基、ABTS~+·、亚硝酸基的IC_(50)值分别为:122.12、130.78、392.09μg/m L;纯化后的多酚样品抗氧化能力比粗品有所增强。     

微型足球机器人守门员策略研究

提出了一种基于区域的防守方法,对不同区域的防守策略进行了分析,给出了参数计算公式．对危险区域的防守策略进行了重点讨论,分析了可能遇到的各种情况．针对比赛规则对机器人持球能力的限制,提出了一种简单有效的防守办法．     

脆化的20Cr1Mo1VNbTiB螺栓的缺口试验

在取自服役12×104 h的20Cr1Mo1VNbTiB螺栓钢的拉伸试样上预制不同底部曲率半径(0.10mm,0.13mm,0.25mm,0.85 mm)和不同深度(0.25 mm,0.50 mm,1.00 mm)的V型缺口,通过拉伸试验研究了脆化后的20Cr1Mo1VNbTiB螺栓钢的缺口性能,并与新材料的缺口试验进...