非正态分布时最小子样容量的确定

对可靠性试验中非正态分布前提下如何确定最少试验个数的问题进行了研究。提出了采用当量正态化方法 ,并综合考虑假设检验的两类错误 ,利用统计推断方法 ,在一定精度指标和置信水平下 ,给出估计母体均值和母体下限值时所需最少试件个数。算例分析说明了该方法的可行性     

上市公司母体企业分离办社会职能的探索和实践

介绍国有企业的经营性资产上市后，留在母体企业的办社会职能尚未由地方政府接管的过渡时期，母体企业主动分离办社会职能的做法。     

对比试验个数与对比误差

介绍疲劳试验时疲劳试样个数的确定及试验误差。重点讨论对比试验时试样个数的确定及对比误差分析，以便正确选择试样个数，使试验误差减少到所要求的范围之内。     

虚拟噪声通道在基于ICA消噪过程中的应用

考虑应用独立分量分析方法进行信号的消噪处理时，要求观测通道的个数大于或等于独立信源的个数的条件，以及实际应用中的噪声源的随机性，尝试引入虚拟噪声通道的概念，克服难以确定噪声源的个数，因而很难满足独立分量分析方法应用要求的限制，根据具体的检测条件和被测对象的特性，引入相应的虚拟通道数，从而提高独立分量分析方法在消噪方面的应用性能。实验表明，利用该方法可以得到很好的消噪结果，有效提高信号的信噪比。     

内齿行星轮传动中内齿行星轮个数的选择

通过对内齿行星轮传动静、动态受力分析，研究了内齿行星轮个数与内齿行星轮传动特性的关系。通过分析得知，内齿行星轮个数为3和6的传动是实用的。     

电感耦合等离子体质谱法测定母体静脉血及胎儿脐带血中微量元素镉和铜

母体和胎儿是两个生命一个整体,两者密切相关[1].孕期母体由于循环血量增加和雌激素的作用,以及由于胎儿发育的需要母体内许多元素要通过胎盘转运给胎儿,此时胎儿体内与母体微量元素的变化以及相互关系是一个值得探讨的问题.本工作拟用电感耦合等离子体质谱(ICP-MS)技术测定母体静脉血及胎儿脐带血中Cu和Cd,以了解母体与胎儿微量元素含量的关系.     

阈-线性模型下安哥拉山羊初生重和产羔数遗传参数的贝叶斯推断

对安哥拉山羊的初生重和产羔数配合阈一线性动物模型进行了二性状遗传参数的贝叶斯分析。采用SPSS13．0软件准备育种数据，用MTGSAM软件对943头安哥拉山羊初生重和产羔数的遗传参数进行Gibbs抽样运算。Gibbs抽样器的运行参数为：共运行550000次，前50000次作为初始化过程舍弃，稀疏间隔为100。后Gibbs分析使用R—CODA软件。结果表明，初生重的直接遗传力为0．329，总遗传力为0．341，属于中等偏高遗传力。初生重的母体遗传力为0．157，初生重的个体直接一母体加性遗传相关为-0．184。产羔数的直接遗传力为0．140，属于低偏中等的遗传力。产羔数的直接加性遗传效应与初生重的母体加性遗传效应间的相关为-0．069。两性状的遗传相关和表型相关分别为0．109和0．018。     

两模态输入整形器的设计方法研究

以两模态输入整形器为例，对级联法和联立方程法这两种设计方法进行研究，并就这两种方法在时滞、脉冲个数、鲁棒性、计算强度等方面进行比较，仿真结果表明这两种方法对系统的两种模态误差均有很好的鲁棒性，级联法设计简单，且对高模态的不灵敏性要高于联立方程法，联立方程法则比较直观，得到的输入整形器包含的脉冲个数少，减少了时滞。     

冲天炉新技术特点及炉气余热利用

介绍了冲天炉炉型特点，风口面积分配比、风口比、风口排距和个数。以及余热利用。     

大落料模具凸凹模堆焊刃口的结构与工艺过程

本文主要介绍大型落料模具凸凹模选用４５＾＃钢做母体、刃口堆焊高强度材质代替整体合金工具钢的堆焊结构和工艺过程，实践证明效果良好。     

Path classification and estimation model based prognosis of pneumatic cylinder lifetime

Prognosis is a key technology to improve reliability,safety and maintainability of products,a lot of researchers have been devoted to this technology.But to improve the predict accuracy of remaining li...     

抗氢钢焊缝的声发射检测分析

采用声发射检测方法对抗氢钢焊缝在受载情况下的变化过程进行监测,提取出对应的声发射信号特征并进行了状态的判断。试验表明,无缺陷试样变形过程中所释放的应变能较小,而抗氢钢焊缝内部气孔缺陷在受载后将发生扩展,试样在断裂前会产生大量高幅值声发射信号。经分析后认为,声发射检测方法有望实现抗氢钢焊接构件的监测与整体性能评估。     

蠕变现象的小冲杆试验研究--蠕变应力分析

主要阐述根据小冲杆试样实测中心挠度求蠕变应力的问题。包括：借助“表征”概念，将试样中心点视为整片试样的表征点；利用压力容器薄膜理论之力平衡关系确定特定时间状态下试样中心区域的应力状态，推导小冲杆试样中心点的蠕变应力估算公式；按该估算公式处理12CrlMoV钢在特定试验条件下获得的小冲杆变试验数据，并对比由此求得的蠕变应力－时间关系与有限元计算的同类结果，根据两者的一致程度判定应力计算模型和工程估算公式的可信度。最后，文章还对具体如何确定特定小冲杆试验之表征蠕变应力值给出了建议。     

Throughput maximization of particle radius measurements through balancing size versus current of the electron probe

In this paper we investigate which probe size maximizes the throughput when measuring the radius of nanoparticles in high angle annular dark field scanning transmission electron microscopy (HAADF STEM). The size and the corresponding current of the electron probe determine the precision of the estimate of a particle's radius. Maximizing throughput means that a maximum number of particles should be imaged within a given time frame, so that a prespecified precision is attained. We show that Bayesian statistical experimental design is a very useful approach to determine the optimal probe size using a certain amount of prior knowledge about the sample. The dependence of the optimal probe size on the detector geometry and the diameter, variability and atomic number of the particles is investigated. An expression for the optimal probe size in the absence of any kind of prior knowledge about the specimen is derived as well.     

疲劳损伤的激光检测及细观初探

利用一种非接触、非破坏的激光衍射谱谱面光强检测方法，对ＬＹ１２ＣＺ铝合金板材试样进行了拉－拉非对称循环疲劳损伤检测。证明谱面光强对疲劳损伤是敏感的；衍射光强比Ｋ随循环次数Ｎ的增加单调下降；损伤变量Ｄ则随Ｎ的增加单调增加，当Ｄ达到其临界值Ｄｃ时疲劳破坏发生。同时对不同循环次数下试样表面进行电镜扫描分析，对衍射光强比变化的表面细观状态进行探讨。     

Automated analysis of submicron particles by computer-controlled scanning electron microscopy

Automated analysis of submicron particles by computer-controlled scanning electron microscopy is generally possible. The minimum diameter of the detectable particles is dependent on the mean atomic number of the particles and the operating parameters of the scanning microscope. The main limitation with regard to particle size is set by the quality of the particle detection system, which generally is the backscatter electron detector. The accuracy of the results of the x-ray analyses is very often strongly affected by specimen damage, omnipresent especially for environmental particles even at low electron energies and probe currents. With the exception for light elements, the detection limit is approximately 1 wt%. Device-related limitations to automated analysis may be specimen drift and an unreliable autofocus function.     

A new methodology to estimate starvation in ball bearings

In agreement with isothermal EHD theory, increases in speed and lubricant viscosity determine the increase in film thickness. Beyond certain limits, both speed and viscosity lead to a decrease in film thickness, as a result of thermal effects and starvation. To estimate starvation limits and film thickness in high-speed, mist-lubricated ball bearings, a new analytical methodology has been developed. This methodology is based both on the oil flow rate in ball-race contacts and Hamrock and Dowson's starvation theory. This new methodology has been used to estimate minimum film thickness in a 7206C angular contact ball bearing, axially-loaded, and rotated between 0 and 35,000 r/min⁻¹. Good correlation between computed and experimental values of the minimum film thickness have been obtained.     

基于有效回波概率估计空间碎片激光测距系统作用距离

基于回波光子数方程估计空间碎片激光测距系统作用距离时,最小可接受回波光子数很难确定。本文提出了通过改变空间碎片实测数据回波稀疏性获得精度变化曲线的退化模型,以"精度不变"作为衡量条件,确定保精度情况下系统最小可识别有效回波概率,从而估算系统作用距离的方法。首先,根据单光子雪崩探测器"关门"特性,得到了有效回波概率与测量距离关系。然后,建立实测数据的稀疏性退化模型得到测量精度与有效回波概率的跃变曲线,根据精度曲线中"保精度平台"的"跳变点"获得最小可识别有效回波概率。最后,根据最小可识别回波概率获得系统对不同大小典型空间碎片的作用距离。分别处理了有效截面积为3.884 0,6.391 2和9.855 5m2的3种典型空间碎片的实验数据,结果表明:系统在满足m级测距精度的前提下,可识别的最小有效回波概率为0.02~0.044,对上述不同特性典型空间碎片相应的最大作用距离分别为820,1 520和2 250km。提出的模型在精度不变情况下解决了系统最小可识别有效回波概率难以确定的问题,大大减少了实验成本。     

Minimum variance lower bound estimation and realization for desired structures

The Minimum Variance Lower Bound (MVLB) represents the best achievable controller capability in a variance sense. Estimation and realization of MVLB for nonlinear systems confront some difficulties. Hence, almost all methods introduced so far estimate MVLB for a certain structure (e.g., NARMAX) or controller (e.g. PID). In this paper, MVLB for desired structures (not restricted to a certain type) is studied. The situation when the model is not in hand, is not accurate, or is not invertible has been considered. Moreover, in order to realize minimum variance controllers for nonlinear structures, a recursive model-free MVC design is utilized. Finally, a simulation study has been used to clarify the effectiveness of the proposed control scheme.