综合布线系统的设计、施工及测试

针对综合布线系统工程设计与施工中存在的问题作一简单的归纳，并提出相应的解决办法。其中解决的办法包括几点重要的内容：设计时注意用户的需求和系统的可扩展性，施工时严格按照规范施工，工程结束后要做出详细的测试方案。接地问题和线缆敷设管路的弯曲问题是在施工时很重要的。测试时应测试的内容有：远端串扰、近端串扰、综合近端串扰、结构回波损耗等。     

Simulation-based sequential analysis of Markov switching stochastic volatility models

We propose a simulation-based algorithm for inference in stochastic volatility models with possible regime switching in which the regime state is governed by a first-order Markov process. Using auxiliary particle filters we developed a strategy to sequentially learn about states and parameters of the model. The methodology is tested against a synthetic time series and validated with a real financial time series: the IBOVESPA stock index (São Paulo Stock Exchange).     

Design of thermophoretic probe for precise particle sampling

We proposed a design methodology for improved thermophoretic probes that can sample particles with high spatial resolution. A bending vibration analysis for the instantaneous motion of a probe has been done together with direct observation of the probe motion and flow disturbance for systematic study of the effect of different designs on particle sampling. Direct observation of the motion of thermophoretic sampling probes revealed that the probe with a low stiffness would result in inaccurate particle sampling. Based on these, the thermophoretic sampling probe was modified to minimize probe vibration and flow disturbance and this modified design was confirmed to sample particles with higher spatial resolution than the original one by examining transmission electron microscope (TEM) images of particles collected in a flame.     

真空蒸发沉积VOPc薄膜及磁场对薄膜结构与性能的影响

用真空蒸发制备了酞菁氧钒 (VOPc)薄膜 ,并在磁场中进行了热处理。用X光电子能谱、X射线衍射、紫外 可见吸收光谱、原子力显微镜等手段对制备的薄膜进行了表征。结果表明沉积的酞菁氧钒薄膜为α 型 ,成分接近酞菁氧钒的分子式。制备的薄膜在磁场中进行了热处理 ,发现磁场使酞菁氧钒薄膜性质发生改变 :UV VIS吸收谱Q带发生红移 ;XRD谱图衍射峰强度明显增强 ,峰位略有变化 ;原子力显微镜 (AFM)分析发现晶粒大小无明显变化。以上结果说明磁场的存在使得VOPc分子在热处理过程中发生了定向的排列     

YGQC磁选机磁系调节系统的模糊综合评判

介绍了设计YGQC干式磁选机模糊综合评判的基本原理。     

Magnetotransport Properties and Mechanism of the A-Site Ordering in the Nd–Ba Optimal-Doped Manganites

The crystal structure and magnetotransport properties of the Nd_0.70Ba_0.30-MnO_3.00−δ manganites have been investigated. The stoichiometric A-site ionic disordered Nd_0.70Ba_0.30MnO_3.00 sample is orthorhombic (SG=Imma) ferromagnet below T _C ≈151 K. It has metal-insulator transition at T _MI ≈140 K and peak of magnetoresistance ∼50% in field of 9 kOe. The anion-deficient partly A-site ionic ordered Nd_0.70Ba_0.30MnO_2.60 sample is ferrimagnet with T _N ≈130 K and has nanometric ∼440 nm grains. The oxygen annealed stoichiometric partly A-site ordered Nd_0.70Ba_0.30MnO_3.00 sample consists of two perovskite phases: (i) A-site ionic completely ordered tetragonal (SG=P4/mmm) NdBaMn_2.00O_6.00 with a Curie point of ∼310 K and (ii) superstoichiometric orthorhombic (SG=Pnma) NdMnO_3.00+γ with a Curie point of ∼120 K. The magnetoresistance of this sample at the room temperature is about 7% in a field of 9 kOe. Considerable changes of the magnetic properties are interpreted as due to the ordering of Nd³⁺ and Ba²⁺ cations as well as the formation of nanometric grains.      

Techniques and Apparatus for Measuring Rotational Core Losses of Soft Magnetic Materials

In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.     

Monotonic and cyclic oedometer tests on sand at high stress levels

In this paper, one-dimensional compression behavior of uniformly graded fine sand is studied with the use of oedometer test at elevated stress levels. To reach the elevated stress levels, testing is performed in a strain controlled manner. In addition, standard stress controlled testing method is also used at lower stress levels for the purpose of comparison. Specimens prepared with initial relative densities ranging from loose to dense are subjected to normal loading as well as hysteretic and repeated loading patterns. Results showed that there is a linear relationship between compressibility index and relative density. The magnitude of compression is mainly influenced by inundation where the compressibility behavior is found to be depending on the initial formation density. Regardless of the initial formation density, convergence to a similar compression index is observed with the hysteretically loaded samples whereas a continuous modification was obtained with repetitively loaded reformed specimens.     

Characterisation of inter-particle forces within agglomerated metallurgical powders

The strength of agglomerates of nickel flash furnace concentrate and dust was determined from experimental observations of agglomerates forming under controlled conditions, combined with mathematical equations from the literature. It was found that the agglomerates had a tensile strength ranging from 0.01 Pa to 38.7 Pa, while inter-particle forces ranged from 2.2 × 10^− 12 N to 1.5 × 10^− 10 N. These values were compared to the expected magnitude of van der Waals, electrostatic, magnetic and capillary forces within the agglomerates, and it was found that both electrostatic and van der Waals forces are likely to contribute to the cohesion of agglomerates, although sub-micron particles and the presence of sufficiently large asperities on the surface of particles limit the magnitude of van der Waals forces. Magnetic forces are large enough to contribute to the cohesion of dust agglomerates, which is in keeping with the high magnetite content of the recycle dust. It is postulated that electrostatic forces, acting over a longer range than van der Waals forces, may be responsible for initially bringing particles together. The methodology for determining inter-particle forces can be applied to the computer modelling of flash smelting systems, as well as other gas/particle systems such as fluidized beds.