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:1672-7207(2011)12-3772-05 Improvement of C4.5 decision tree continuous attributes segmentation threshold algorithm and its application YAO Ya-fu, XING Liu-tao (School of Mechanical and Electrical... algorithm, which selects the best segmentation threshold of the continuous attribute values, was proposed. According to the principle that there always exist the boundary points at the optimal segmentation......
统计量,平方预测误差统计量(squared predicted error, )相似,ICA采用指标,和进行故障检测和诊断,不同的是通过核密度估计(kernel density estimation, KDE)方法[14]获得故障检测三指标的控制限.KDE方法为基于ICA的故障检测方法求取控制限提供了可能,但当数据分布不均匀时,该方法获取的监控阈值可能不合理,导致故障检测效果不平稳.LEE等[15]提出改进的ICA算法并将其用于故障检测及诊断,有效地提高了故障检测率;YANG等[16]针对复杂工业过程中的动态特性和难以检测的微小故障,提出了规范变量-独立成分分析(canonical varia......
, Yueyang 414000, China) Abstract: Based on field dynamic response testing results and the critical dynamic stress and fatigue dynamic shear strain threshold obtained from fatigue test indoor... were also given. Influences for water content ratio and confining pressure on replacement thickness of cutting bed were discussed. The results show that the dynamic shear strain threshold increases......
不同化学蚀刻法对石英基片激光损伤阈值的影响 吕海兵1,郑万国1,晏良宏1,赵松楠1,袁晓东1 (1.中国工程物理研究院激光聚变研究中心,绵阳,621900) 摘要:为提高三倍频光学元件的表面损伤阈值,采用了不同方式对石英基片进行酸蚀刻,利用原子力显微镜观测了基片蚀刻前后的表面微观形貌,并在激光损伤测量装置上进行了R:1方式的阈值测试,比较分析了蚀刻前后基片激光损伤阈值和表面形貌的变化,并比较了不同抛光质量石英基片蚀刻效果的差异.通过实验研究,总结了不同蚀刻方式的优缺点,研究表明酸蚀刻法可以有效提高石英基片激光损伤阈值. 关键词:激光损伤阈值; 湿化学蚀刻; 石英基片; 表面形貌; laser damage threshold; wet etching; fused silica; surface morphology; [全文内容正在添加中] ......
实时控制过饱和度降温法生长KDP晶体 孙洵1,王圣来1,曾红1,付有君1,高樟寿1,李义平1 (1.山东大学) 摘要:用变压器型电导仪实现了KDP晶体生长过程中溶液的浓度和过饱和度的实时测量与控制,测量精度0.03g KDP/100g H2O(0.10%相对过饱和度),控制精度与测量精度相当. 过饱和度实时控制系统提供了一种方法,可以研究在不同工艺条件生长KDP晶体时,过饱和度与晶体生长和性能的关系. 用分析纯原料生长KDP晶体,发现随着过饱和度的增大,晶体的生长速度加快,晶体的均匀性降低. 过饱和度实时控制系统可以使KDP晶体在相对恒定的过饱和度下生长,提高了晶体生长的均匀性,抑制了生......
%~30%时, 碳纤维石墨水泥砂浆试样的体积电阻率与压应力呈现良好的可重复性, 电阻值在应力加载时几乎呈线性下降, 而卸载时增加. 关键词:碳纤维; 石墨; CCCW; 渗流阈值; 压阻特性; carbon fiber; graphite; CCCW; percolation threshold; piezoresistivity; [全文内容正在添加中] ......
threshold which was assumed to be the starting point of initial yield phase. Furthermore, the theoretical correlation between model parameter and deformation moduli of rock under triaxial compression... mechanics; the principle of minimum dissipative energy; unified energy yield criterion of rock; damage threshold; damage evolution equation 漫长的地质演变过程及复杂的三向应力环境使岩石内部产生大量非连续且形态不规则的隐裂隙,微裂纹,微孔洞及节理等微缺陷,微缺陷......
Influence of Stress Ratio and Loading Condition on Near-threshold Fatigue Crack Growth BehaviourB.Weiss,R.Stickler摘 要:<正> Near-threshold fatigue... closure effect as well as the effective fatigue threshold,It was found that thefatigue threshold for R=0 is higher than those for R=-1 and R=0.4,for which almost the samethreshold value......
of a threshold stress due to an interaction between the dislocations and Cu-rich precipitates during creep deformation.The creep mechanism is associated with the dislocation climbing governed by the matrix lattice diffusion.The origin of the threshold stress is mainly attributed to the coherency strain induced in the matrix by Cu-rich precipitates.The theoretically estimated threshold stresses from......
and electrical resistance measurement The experimental results shows that impact damage energy threshold value of carbon fabric/epoxy-matrix composites can determine by using ultrasonic F-scan. When the impact energy exceeds the threshold value, damage is generated in composites. Electrical resistance of impacted composites is changed owing to the contact of each carbon fiber unit in composites, which......