α-Fe/Nd2Fe14B稀土永磁合金定量相分析

通过对Ｎｄ２Ｆｅ１４Ｂ四方相单胞分析,确定其结构因数,进而建立了稀土永磁合金直接比较法定量相分析计算程序。在对单相计算结果与实验值取得一致的基础上,对α－Ｆｅ／Ｎｄ２Ｆｅ１４Ｂ双相稀土永磁合金进行了定量相含量测算和分析。     

露天矿采剥工程量计算与可视化新方法研究

针对目前露天矿采剥工程量计算中存在的精度低、自动化程度不高、不直观等问题,提出基于Surfer的露天矿采剥工程量计算与三维可视化新方法;介绍了数据野外采集和插值方法评定与选择,并对新方法计算原理与精度作了分析;最后将计算结果进行三维可视化。通过理论分析与实例演示证实这是一种精度高、速度快并且直观的露天矿采剥工程量计算方法。     

数据拟合法在等离子弧温度场测算中的应用研究

等离子弧作为新兴的高温热源在冶金工业方面应用发展相当迅速。由于对其内部温度进行光谱法测算中Abel逆变换的存在 ,使得温度场的计算比较困难。本文基于最小二乘原理对原始离散数据进行拟合 ,然后利用拟合曲线对Abel逆变换进行计算。实验结果表明该算法精度很高、程序实现方便 ,并可有效处理积分奇异点问题 ,从而得到了计算等离子弧温度场的一种有效方法。     

KR950轧辊磨床曲线磨削机构磨削误差分析及调整

针对轧辊磨床在磨削曲线工件时,产生曲线精度误差的原因分析,通过曲线量的计算、系统调整、轧辊曲线的磨削调试等手段,找到消除磨削误差的有效方法,提高了轧辊曲线磨削精度。     

中小型软件项目成本测算的实践

以面向中小软件开发公司和一般软件开发用户的成本测算为应用对象,以任务分解方法为基础,依据软件项目管理的实例,提出方法实用、计算简便的软件成本测算方法,并通过对软件工作量的估算和软件的成本测算以及目标百分比的核定与使用来实现.     

矿山电气设备的稳定性及可靠性测试分析

在矿山行业中,电气设备的应用是必不可少的。然而,传统的性能测算方法难以实现对其精确的计量和分析。对应用于矿山上的电气设备的稳定性能及可靠性能进行了测算分析,建立了基于仿真计算的智能型建模测试机制,还通过对比传统的测算方式与基于建模机制的测算方式结果进行了对比研究,验证了矿山电气设备的稳定性和可靠性,提高了电气设备在不同矿山应用下的性能,为提高并优化矿山电气设备的研究提供了指导性理论依据。     

热工测试中空气过剩系数计算方法的比较

通过对热工测试中常用的空气过剩系数计算方法的误差对比,指出了不同测算方法的使用范围,及使用时的注意事项。     

盐浴炉的电能利用率与节电措施

讨论了盐浴炉电能利用率的计算方法，在此基础上，通过实验提出若干节电措施，给出电能利用率的测算结果。     

金属材料加工设备的数学建模相应计算分析

为解决金属材料加工设备在实际运行过程中的不确定性和加工精度预测不可靠问题,开展金属材料加工设备的数学建模相应计算分析研究。通过金属材料加工设备相关数据采集、数字加工设备模型构建,实现对加工设备的数学建模,并以此为基础,对加工过程中切屑折断函数和加工误差量进行计算,以期为金属材料加工设备的高精度加工提供数据支撑。     

冷连轧轧制力计算模型及改进方案

过程控制系统要求数学模型能正确反映规律性,运算简单,并且有较高的预报精度。轧制力计算模型是过程控制数学模型的核心,轧制力的计算精度直接影响到板形与板厚控制的精度。为了提高轧制力计算的精度,通过对冷轧轧制力特点的分析和计算模型的研究,我们在现有Hill公式的基础上,考虑张力对计算冷轧带钢轧制力的影响并借助于自学习计算功能,通过添加张力影响因子和模型自学习系数对Hill公式进行了改进,在保证轧制力预报精度的同时实现轧制力的在线计算。实际数据测试结果表明轧制力在线计算模型的预报精度误差在±5%以内。     

Optimal Spacing in an Array of Fully Penetrating Ditches for Subsurface Drainage

A methodology for optimal spacing in an array of ditches fully penetrating into homogeneous and isotropic porous medium of finite depth over an impervious layer is presented. The cost function includes the depth-dependent earthwork cost and the capitalized cost of pumping of drain discharge. Essentially, it is a problem of minimization of a nonlinear objective function of single variable. The input variables consist of rainfall intensity, hydraulic conductivity of the porous medium, width and depth of ditches, earthwork cost, cost of pumps and pumping energy cost, efficiency of pumping unit, and rate of interest. Using nonlinear data fitting method an explicit equation has been proposed for computing the optimal spacing between the ditches.     

DIMINE填挖方量计算原理与方法研究

填挖方量计算是土石方工程的重要环节之一。为了正确应用填挖方量计算方法,提高计算精度,分别研究了DIMINE软件中4种不同计算方法的基本原理。结合不同的工程案例,以相应的布尔体积为标准,对4种方法的计算结果进行对比分析,探讨了各种计算方法存在误差的原因,以及对不同数据特征的适应性。研究结果表明,由于原始数据的地貌特征、地形变化趋势及坡度变化的影响,不同方法的计算精度不同。根据每种计算方法的基本原理和实验结果的误差分析,针对在不同数据特征条件下填挖方量计算方法的应用问题,提出了相应的建议,为正确使用DIMINE软件进行填挖方量计算提供参考。     

Immune thrombocytopenia in children: the immune character of destructive thrombocytopenia and the treatment of bleeding

It is now recognized that different forms of destructive thrombocytopenia due to antibody binding to platelets exist, which can be differentiated by sensitive new assays. Thus, the name has been changed from idiopathic to immune thrombocytopenic purpura (ITP). The immune character of ITP has been further supported by the success of treatment with human antibody concentrate-immunoglobulin treatment. During different studies of ITP in children, it has been recognized that only patients with bleeding in addition to a platelet count less than 20 x 10(9)/L need to be treated. The various forms of treatment are reviewed.     

原子发射光谱法测定钢中微量钙

用光电直读光谱仪分析钢中的钙,可以满足炉前分析对快速、准确的要求。通过实验,总结出了一套用光电直读光谱仪,同时分析钢中的钙及Ｃ、Ｓｉ、Ｍｎ 、Ｐ、Ｓ、Ｃｕ 等元素的方法,其测量精密度、检测限及分析速度完全可以满足炉前分析的要求     

CASS在龙首矿区绿化场地平整与土方计算中的应用探讨

龙首矿区绿化工程中有很多场地平整,土方回填和开挖工作。CASS用于设计场地平整计划并计算土方量。选择合理的土方调配计划尽量实现场地的填挖平衡。避免重复回填、开挖和运输,以达到优化场地平整设计和土方计算的最优解目的,以降低工程造价,提高工程效率,也为龙首矿区绿化设计方案提供设计依据。     

库尔特激光粒度分布仪在测定钽铌复合物粒度分布中的应用

文章介绍了应用库尔特激光粒度分布仪测定钽铌复合物粒度分布的方法。钽铌复合物颗粒均匀分散在二次去离子水中,以一定的流速通过激光束。衍射光经透镜被光电探测器接收转化为电信号,由此测出颗粒的粒度分布,并讨论了应用中的经验。该方法容易建立,精密度高,能够给出多种粒度分布结果以及参数,非常适合生产过程中的应用。     

拐点计数法及其在材料科学中的应用

采用集合论的形式对一种体视学新方法,即拐点计数法及相应的体视学基本关系式进行了描述和推导,使之更加条统、准确和明瞭。并进而讨论了它们在材料科学中的各种可能应用及有关问题。     

Anisotropy in the Spatial Distribution of Roller-Measured Soil Stiffness

The geostatistical analysis of roller-measured soil properties (from continuous compaction control and intelligent compaction) is required for advanced quality control/quality assurance of earthwork and asphalt compaction. This paper explores the existence of anisotropy in the spatial distribution of roller-measured soil stiffness and the effect of anisotropy on kriging. Field testing was conducted to collect roller measurement value (MV) data over typical roadway embankment evaluation areas and on a large square area to enable a robust investigation of anisotropy. The semivariogram analysis of the field data clearly indicates that range anisotropy exists. The spatial distributions of roller MV data are different in the longitudinal x-direction than in the transverse y-direction. Magnitudes of range anisotropy (x-range/y-range) varied from 2.4 to over 5. The observed range anisotropy is not due to the roller measurement system; rather, it is likely due to the directional nature of earthwork construction activities and to alignment geometry. The influence of anisotropy on kriging was found to be significant when considering the use of kriged data in earthwork specifications. The error introduced by not accounting for anisotropy in kriging varied from 5 to 17% when considering pass to pass or layer to layer map analysis. The anisotropy in the spatial distribution of roller MV data should be factored into kriging and other geostatistical analyses. For typical earthwork area geometries, the roller mapping procedure requires a slight modification to determine the y-range and anisotropy ratio.     

Fuzzy Optimization Model for Earthwork Allocations with Imprecise Parameters

Existing linear programming (LP) models of earthwork allocations in roadway construction assume that unit cost coefficients of earthwork activities and borrow pits/disposal sites capacities are certain and deterministic numbers. However in real-world problems there are naturally some uncertainties inherited in these values, which make it difficult to represent a single value as the candidate of entire possible values. This paper presents a fuzzy linear programming (FLP) model of earthwork allocations based on the fact of assuming unit cost coefficients and borrow pits/disposal sites capacities as fuzzy numbers while minimizing total earth-moving cost as an objective function. A method based on α cuts of a fuzzy set is used to take the uncertainty in borrow pits/disposal sites capacities into account. The uncertainty in fuzzy cost coefficients of the objective function and its effects on decision variables of the earthwork allocations model are also considered using the method presented by Chanas and Kuchta in 1994. Subsequently, a more general model is suggested which considers both uncertainties in borrow pits/disposal sites capacities and cost coefficients simultaneously. It is demonstrated that the presented FLP, compared to a deterministic LP, introduces a more robust solution; as the result of giving fuzziness to the uncertain parameters. Such a solution could be beneficial in real world decision making where uncertainties on resources and activities cost exist.     

锁相技术在单片机无功功率测量中的应用

介绍提高采样精度的锁相环同步采样技术,该方法适用于电网有畸变及频率有波动的电网测量,并提出了实现方案。