智能铸砂发气性能试验机高温监控研究

本文分析了影响智能铸砂发气性能试验机高温控制精度的主要原因, 并详细介绍了提高高温控制精度的一些有效措施     

电动头套管焊缝断裂的失效分析

对２ＲＩＳＯ１２ＶＰ电动头失效原因进行了研究。熔敷金属的化学成份分析结果指出其钴和钨的含量分别高达３９．６％和９３．５％,硬度测量表明,平均显微硬度为ＨＶ６５０。试验结果表明,焊接填充材料属司太立合金。宏观金相观察结果表明,焊缝中有气孔存在。     

某含铜金矿石选矿试验研究

针对某含铜金矿石,进行了直接全泥氰化、氨浸—氰化、酸浸—氰化、浮选试验研究。其结果表明,采用"先硫后氧"优先浮选—浮选尾矿氰化工艺流程,获得了较好的技术指标,金回收率可达到93.41%,银回收率达到68.81%。同时,对浮选所得的两种精矿进行氰化试验探索,也获得了较好的浸出指标。     

Effect of Pseudomonas fluorescens on beef discoloration and oxymyoglobin oxidation in vitro

The relationship between bacterial growth and oxymyoglobin oxidation in vitro and in meat was studied. In the in vitro study, oxymyoglobin was combined with Pseudomonas fluorescens or sterile nutrient broth (control) in an airtight vessel. P. fluorescens samples showed greater metmyoglobin formation and oxygen consumption than controls. The P. fluorescens population in the reaction vessels was correlated with metmyoglobin formation (r = 0.85, P < 0.05) and oxygen consumption (r = 0.91, P < 0.05). When P. fluorescens and oxymyoglobin were combined in an airtight vessel, reducing the headspace from 13 ml and 9 ml to 3 ml resulted in greater metmyoglobin formation (P < 0.05). In the meat study, beef cores prepared from longissimus lumborum were inoculated with P. fluorescens (10(7) CFU/cm2) or sterile peptone water (control), packaged under 1% O2 (+99% N2), air, or 100% O2 and stored at 4 degrees C. Inoculated beef cores showed higher bacterial loads and metmyoglobin formation than their respective controls during 10 h storage in 1% O2, 3 days in air, and 7 days in 100% O2 (P < 0.05). This finding indicated that P. fluorescens could accelerate beef discoloration. Overall, studies demonstrated that oxygen consumption concomitant with P. fluorescens growth decreased partial oxygen pressure, which accelerated oxymyoglobin oxidation.     

卧式活套中带钢跑偏问题分析与改善措施

针对带钢连续生产线上卧式活套中无法避免的带钢跑偏问题,对各种不同机组中卧式活套中带钢的跑偏问题进行分析研究,提出了多种不同的应对措施,通过在卧式活套中改进设计或增加设备,在现场运行过程中切实可行的缓解了带钢跑偏问题,为今后进行卧式活套设计提供了可靠的依据。     

带有随机系数的双线性INAR(1)模型的统计推断

基于带有随机系数的二项稀疏算子构造双线性INAR(1)模型,推导了模型的统计性质．采用修正的矩估计法对模型进行参数估计并进行了模拟研究．最后给出一个实例应用,结果表明基于带有随机系数的二项稀疏算子的双线性INAR(1)模型是更适合数据的模型．     

Scanning transmission ion microscopy computed tomography (STIM-CT) for inertial confinement fusion (ICF) targets

ICF target quality control in the laser fusion program is vital to ensure that the energy deposition from the lasers results in uniform compression and minimization of Rayleigh–Taylor instabilities, which requires surface finishes on the order of submicron-scale. During target fabrication process the surface finish and the dimensions of the hohlraum need be well controlled. Density variations and nonspherical or nonconcentric shells might be produced. Scanning transmission ion microscopy computed tomography (STIM-CT) is able to reconstruct the three-dimensional quantitative structure of ICF targets a few tens of micrometers in size. Compared to other types of probe techniques, the main advantage of STIM-CT is that quantitative information about mass density and sphericity can be obtained directly and non-destructively, utilizing specific reconstruction codes. We present a case of ICF target (composed of polyvinyl alcohol) characterization by STIM-CT in order to demonstrate the STIM-CT potential impact in assessing target fabrication processes.     

一个拓扑熵等于∞的非浑沌系统

本文构造了一个离散动力系统(E,σ),其中E是一个可数集。σ:E→E是一个连续映射,满足: 1)σ的拓扑熵是+∞; 2)σ的非游荡集是空集; 3)σ只在E的聚点处有初值敏感性     

Rotor resonances of high-speed permanent-magnet brushless machines

For high-speed machines, in particular, it is very important to accurately predict natural frequencies of the rotor at the design stage so as to minimize the likelihood of failure. Finite-element analysis and experimental measurements are used to establish the natural frequencies and modes of the rotor of a high-speed permanent-magnet brushless motor, and to assess the influence of leading design parameters, such as the active length, the shaft diameter and extension, the bearings, and the material properties.     

局部阻塞管道中湍流的数值预测

本文提出了一个在回流区壁面附近湍流二方程模式的改进方法,并湍流的涡量输运方程及流函数方结合衰减函数的差分格式计算了局部阻塞管道中程,所得到的湍流的时均速度分布与前人的数值结果相比更接近实验结果.