基于PID-二分组合控制算法的分布参数空气源热泵仿真模型的研究

采用分布参数法建立双级压缩空气源热泵系统热力学模型,建立一种基于PID-二分组合控制算法的全系统循环分布参数模型,并结合实验数据验证该模型的准确性。结果表明：系统模型在双级压缩制热模式下制热性能系数（COP）的模拟数据与实验数据的平均偏差为5.41%,两者在不同运行模式下的最大偏差不超过15%,均在可信范围之内,模型能准确反映系统性能随外界参数变化的规律;该模型与单独使用比例积分微分（PID）控制算法的分布参数法模型相比,总迭代次数较原模型减少约2.96倍,极大减少了模型的计算量,可在保证模型精度的情况下提升模型的计算速度。     

Phase equilibrium in systems based on oxides of zirconium,lanthanum and samarium

According to the results of the samples studied by X-ray diffraction and microstructural analyzes the phase equilibria in the binary La₂O₃ – Sm₂O₃ and ternary ZrO₂ – La₂O₃ – Sm₂O₃ systems were studied. The boundaries of the phase fields of the binary system are specified and an isothermal cross section of the ternary state diagram of the ZrO₂ – La₂O₃ – Sm₂O₃ system at a temperature of 1500 °C is constructed. No new phases have been identified in the studied systems. It is established that in the ternary system ZrO₂ – La₂O₃ – Sm₂O₃ at 1500 °C fields of solid solutions on the basis of cubic (F) modification with structure of fluorite type, tetragonal (T) modification of ZrO₂, monoclinic (B) modifications of Sm₂O₃, hexagonal (A) are formed. La₂O₃, as well as an ordered phase with a structure of the type of pyrochlore Ln₂Zr₂O₇ (Py). The boundaries of the phase fields and the parameters of the unit cells of the formed phases are determined. A characteristic feature of this isothermal cross section is the formation of a continuous series of solid solutions based on the phase of the pyrochlore type La₂Zr₂O₇ (Sm₂Zr₂O₇). The limiting solubility of Sm₂O₃ in the ordered phase La₂Zr₂O₇ is 16 mol. % along the section Sm₂O₃- (67 mol.% ZrO₂ - 33 mol.% La₂O₃). The solubility of La₂O₃ in the solid solution Sm₂Zr₂O₇ is slightly less and is 11 mol. % along the section La₂O₃- (67 mol.% ZrO₂ - 33 mol.% Sm₂O₃). The isothermal cross-section of the state diagram of the ZrO₂ – La₂O₃ – Sm₂O₃ system at 1500 °C is characterized by the presence of three three-phase (Py + T + F), (A + Py + B), (Py + F + B) and eight two-phase (A + Py), (B + A), (B + Py), (F + B), (T + F), (Py + T), (F + Py-two) areas.     

Cyclic thermal shock resistance for MgAlON–MgO composites obtained with additions of spent MgO–C brick: Microstructure characteristics,thermal shock parameter and thermal shock mechanism

Thermal shock parameters (R, R''', R'''' and R_st) of MgAlON–MgO composites obtained with additions of spent MgO–C brick were calculated using measured mechanical properties and thermal expansion coefficient, determining their resistance to fracture initiation and crack propagation. The cyclic thermal shock experiments of MgAlON–MgO composites performed from 1398 K to ambient temperature indicate that as number of thermal shock cycle increases, retained strength ratio of MgAlON and MgAlON–4.2 wt%MgO sharply decrease and then keep constant, while that of MgAlON–10.5 wt%MgO and MgAlON–15.7 wt%MgO slowly decrease. The reason for the difference is that MgAlON and MgAlON–4.2 wt%MgO show low value of R''' and R'''', and high value of R and R_st. Moreover, precipitation of impurity containing Fe may play a positive role in improvement of thermal shock resistance of MgAlON–MgO composites. MgAlON?4.2 wt%MgO has the maximum retained strength (55 MPa) even after 5 thermal shock cycles, which is expected to be used in the metallurgical industry.     

C105管桩混凝土设计参数取值的探讨

通过试验得出了C105混凝土100 mm×100 mm×100 mm立方体非标准试件抗压强度换算系数以及C105混凝土的标准方差和强度变异系数。采用理论计算,得到了棱柱体抗压强度与立方体抗压强度的比值α_c1,并与试验实测平均值进行了比较,验证了理论计算方法的可行性。此外,通过对比分析,探讨了直接外延法和引用公式法两种C105混凝土设计参数计算方法的正确性,研究结果可为C105管桩混凝土的设计和应用提供参考。     

RouterOS在电子阅览室网络管理中应用与实践

本文探讨利用RouterOS软路由来建设图书馆电子阅览室网络的低成本、高性能解决方案,介绍了ROS的特点及其安装和配置过程,尤其在电子阅览室网络安全方面进行了详细分析并给出有效的配置.     

A tree-based address configuration for a MANET

This paper proposes an address configuration scheme for a MANET. In this paper, the tree-based architecture and the algorithm of constructing a MANET are presented. In this architecture, a proxy node can assign a unique address for neighbor new nodes, so the address configuration task is distributed around all proxy nodes. The transmission of control packets is controlled within one-hop scope, so the cost is reduced and the delay is shortened. Through this architecture, the address resources released by failed nodes can be automatically reclaimed for reuse, so a proxy node has always the sufficient address space for assignment. In order to ensure the uniqueness of a node’s address, the paper also proposes the MANET merging and partitioning algorithms. Finally, this paper evaluates the performance metrics of both the proposed scheme and the existing schemes, and the results show that the proposed scheme reduces the address configuration cost and shortens the address configuration delay.     

乙烯-乙酸乙烯酯共聚物Levapren 800硫化胶溶度参数的测定及应用

采用溶胀实验及计算机HSPiP软件对牌号为Levapren 800的乙烯-乙酸乙烯酯硫化胶的溶度参数进行了研究。结果表明,单一溶剂与混合溶剂都可用于Levapren 800硫化胶溶度参数的测定,用溶胀法测得其一维溶度参数(δt)为18.90~19.25(J/cm3)1/2。通过HSPiP软件测得Levapren 800硫化胶的δt为19.97(J/cm3)1/2;三维溶度参数的色散力、极性力和氢键力溶度参数分别为18.20,5.50,6.10(J/cm3)1/2。利用三维溶度参数可以预测Levapren 800硫化胶在标准实验油中的溶胀行为;相对能量差对预测聚合物在溶剂中的溶胀性能方面具有一定的应用价值。     

基于振动信号的深沟球轴承滚动体故障诊断研究

目前针对滚动轴承内、外圈故障的诊断方法较为有效,但难以诊断滚动体故障。针对这种情况,利用时域统计参数(有效值、峭度、脉冲因数、裕度因数)与Hilbert包络谱两种方法,对不同转速、负荷和故障程度情况下滚动体故障与正常状况的振动加速度数据进行比较分析,得出了滚动体故障难以诊断的原因,并给出了解决方法。     

余热锅炉蒸汽流量的温度压力补偿及在DCS系统中的实现方法

将"IFC-1967公式"用于水蒸汽流量的温度压力补偿,可以保证企业精确测量及统计蒸汽流量和累计用量。利用DCS系统提供的结构化文本编程组态方式,将IFC-1967公式写入到系统,并封装成通用功能块,在DCS系统中实现了对余热锅炉过热蒸汽流量的准确测量。