共查询到20条相似文献,搜索用时 15 毫秒
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采用机理分析与统计分析相结合的方法,对对硝基苯胺生产过程进行了调优,得出了“变温操作”的结论。反应过程的保温时间缩短了20%,产品质量稳定。在不增加设备的情况下,每年可增加产量48.5吨。 相似文献
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基于ALE方法分析楔形体入水问题,楔形体采用拉格朗日网格离散,空气和水采用ALE网格离散。将楔形体视为刚体,空气和水的力学行为分别采用Gamma定律和GRUNEISEN状态方程模拟。讨论ALE流固耦合关键字中罚函数罚因子的取值方法,提出相应的建议原则;分析水域截断边界对楔形体响应的影响,给出模拟无限水域的截断边界位置的建议值;分析楔形体表面压力振荡的原因,提出楔形体表面压力获取方法。通过试验结果对比分析,验证方法的合理性。 相似文献
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The present paper deals with the variational approach for solving a clamped rectangular plate under a uniform load. The increasing use of composite materials for plate-type structures intensified the need for solutions of rectangular plates. The variational approach has a broad range of applications in solid mechanics. The methods used to solve the problem consider the minimum total potential energy approach. The maximum deflection is obtained for a square plate by the Ritz, Galerkin and Kantorovich methods. The aim of this paper is to find an approximate solution of higher accuracy. Numerical results for various components of stresses are found and plotted in the form of curves. The results obtained by various methods are compared with those reported earlier. The results show reasonable agreement with the known results, but with a simple and practical approach. The physical aspect of the concept is the immediate use of these results in solid and structural mechanics. 相似文献
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Simulation of partially observed Markov decision process and dynamic quality improvement 总被引:1,自引:0,他引:1
Computer simulation is used to compare three quality policies. The first policy is ‘do-nothing’. The second is an appraisal policy. The third policy includes prevention that leads to process quality improvement. The simulation model is based on a Partially Observed Markov Decision Process (POMDP). The unobserved states of the process depend on the failure rate, λ. The observed process output is the number of conforming and nonconforming products. The process performance is measured by quality costs per unit. The simulation language used is SLAM II. The power of using computer simulation to model the dynamics of process quality improvement is discussed. 相似文献
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《Calphad》2017
The Au-Ni nanoparticles (NPs) were prepared by oleylamine solvothermal synthesis from metal precursors. The Au-Ni phase diagram prediction respecting the particle size was calculated by the CALPHAD method. The hydrodynamic size of the AuNi NPs in a nonpolar organic solvent was measured by the dynamic light scattering (DLS) method. The average hydrodynamic sizes of the nanoparticle samples were between 18 and 25 nm. The metallic composition of the AuNi NP samples was obtained by inductively-coupled plasma atomic emission spectroscopy (ICP-OES). The metallic fraction inside AuNi NPs was varied Au-(30–70) wt%Ni. The steric alkylamine stabilization was observed. The individual AuNi NPs were investigated by transmission electron microscopy (TEM). The dry nanopowder was also studied. The structures of the aggregated samples were investigated by scanning electron microscopy (SEM). The AuNi NPs reveal randomly mixed face-centered cubic (FCC) crystal lattices. The phase transformations were studied under inert gas and air. The samples were studied by differential scanning calorimetry (DSC). 相似文献
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基于RS与GIS的典型地区土地利用/覆盖变化研究——以三江源生态环境重点保护区玛多县为例 总被引:5,自引:0,他引:5
典型地区和脆弱区的土地利用/覆盖变化是区域性研究的重要内容。三江源地区是国家级自然保护区,生态系统异常敏感和脆弱。以典型地区玛多县为案例,基于RS和GIS技术,系统研究了该地区土地利用/覆盖变化及其对景观格局的影响,探讨了生态环境演化过程,可为更广泛的区域性综合提供基础。研究发现:①10 a间,该地区湿地、水体和天然草地明显减少,湿地减少比例达到36.63%,大于6 hm2的湖泊减少近半数;沙地,裸地和盐碱地等明显增加,草地退化、沙漠化严重;②天然草地、裸地、沙地、水体、湿地和盐碱地之间的类型转化较为明显,且与水资源又有密切的关系。③多样性、均匀性指数和景观异质程度提高,土地趋于多样化和均匀化;裸地、沙地优势度增加,湿地、水体和天然草地优势度减少;整体破碎化程度呈缓慢减少趋势,而湿地、沙地破碎度增加。④综合土地利用动态度为0.98,天然草地、裸地、湿地、沙地动态面积变化较大。⑤研究区的土地利用/覆盖变化将深刻影响该地区的生态过程,同时还将影响三江源地区的水源涵养和供给。 相似文献
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基于码重分布的系统循环码识别方法 总被引:1,自引:0,他引:1
介绍系统循环码的定义及矩阵描述,分析其码重分布特性,根据向量间距离的概率定义码重分布距离,推导随机序列的理论码重分布概率,提出实际序列码重分布概率的估计方法和利用实际序列的码重分布概率和随机序列的理论码重分布概率之间的距离估计码组长度和起始点的方法,在此基础上利用高斯消元法估计生成矩阵和校验矩阵,并提出了在误码情况下的识别方法。最后并对不同长度的码进行仿真实验,结果表明文中方法能够在误码为10-3的情况下有效地识别中短码。 相似文献
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讨论了交—交变频调速系统故障诊断的重要性,在当前的检测方法与故障诊断手段研究的基础上,提出了基于DSP和小波分析的变频调速系统故障诊断方法,建立了故障诊断系统;采用了基于小波能量的机电设备状态检测方法,充分利用了DSP强大的数据处理功能,以及小波分析所具有的对非平稳信号的分析处理能力和多分辨力的特性;建立了交—交变频调速系统的数学模型。经仿真实验证明:该方法适用于变频调速系统的故障诊断。 相似文献
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基于采样数据的线性变换,提出了一种曲线变形的思想;设计一种以Lagrange插值为基础的曲线变形算法,并进行算法复杂度分析。该方法能实现代数曲线间的变形处理,具有普遍的适用性和较高的计算精度。通过给出数值实例,验证了算法的有效性和可行性,该算法提供了曲线变形的一种有效途径。 相似文献
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阐述了光电探头线性测量原理和方法,提出了基于双光源叠加法,利用积分球混光完成辐照度叠加,测量了超高亮LED随内部电流变化的光谱特性,测量结果证明:辐照光源使用超高亮LED的可行性。设计中以计算机编程自动控制实现智能化和自动化完成光电探测器的线性测量为宗旨,对系统的各部分结构、原理、特点及创新性进行分析。讨论了测量系统的不确定度来源与处理方法。对硅光电探头进行多次线性测量,重复精度优于±0.5%,测量结果证明:该系统设计自动化程度和精度较高,可以作为光电探测器线性测量装置。 相似文献
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Fuzzy models are known for their ability of precise data approximation. They can be used in automatic control as controllers. One of the techniques is based on inversion of fuzzy models. Fuzzy models can be inverted exactly or approximately. The exact inversion requires special features of fuzzy models. The approximate methods can be applied to a wider class of fuzzy models. The paper presents an approximate inversion of a fuzzy model with parametrized consequences. This fuzzy model cannot be inverted exactly. The presented approach inverts an existing fuzzy model with respect to any input. The inversion procedure uses the Ridders algorithm. The inversion is fast and does not require a separate training for each inverse input. The convergence of this approach is faster than linear. The paper formulates a theorem that shortens a search interval and may help to accelerate an inversion. The paper is accompanied by numerical examples. 相似文献