单片机在数显时间继电器质量检测中的应用

介绍用单片计算机测量数显时间继电器计时精度的方法;包括单片计算机检测台硬件的配置、软件的设计和误差的分析等.

数显时间控制装置

热处理用的箱式炉一般用于回火、退火等工序,每一工序所需时间较长,操作者一旦忘记了工序的终止时间就浪费了电能,且影响了工件质量。本人为此设计了数显时控装置,能24h内预置好时间后,自动接通或关断炉子的电源,同时作声光报警,提醒操作者作下一工序的操作,如调整温度仪表的温度设定、重调置预置时间等。本装置体积小(150mm×100mm×50mm)。

数显时间继电器专用芯片DNL9204的功能扩展

本文介绍了数显时间继电器专用芯片DNL9204增设秒点闪烁、暂停功能的方法以及清零功能的改进方案。

机电式时间继电器故障分析与排除

在繁多电气控制电路中，使用机电式时间继电器的还有一些，尤其是老型进口旧设备。出现故障用电子及数显时间继电器代替，有的因外观、体积、安装位置、电压等级等原因还有一定困难，购买新的同型号的往往又很难办到（有的已淘汰）。在特殊环境中（如大型闸流管整流、逆变、

WPF-2交流电弧发生器的改造

介绍利用数显时间继电器实现了WPF -

润滑液加温搅动自控仪设计

本文介绍了润滑液加温、搅动自控仪的应用范围、组成和工作原理及该自控仪的主要特点,为液体的恒温加热及搅动提供参考。

金门子电气公司

随着工厂自动化的迅猛发展,各种基础自动化元件被普遍采用,金门子公司引进具有目前国际先进水平的工艺制造设备,包括德国西门子公司的传感器专用生产线、专用检测设备,美国的丝网印刷机,英国的厚膜测试仪、激光修调机,日本的自动贴片机等,专业研究、开发、生产各种系列的接近开关、红外线光电开关、霍尔开关、磁性开关、位移量线性传感器、超声波传感器、色标传感器、人体红外线光电开关、安全光幕传感器、数显时间继电器、可编程时控器、计数器。

Microscopic phase-field simulation for nucleation incubation time of Ni_(75)Al_xV_(25-x)alloy

With the microscopic phase-field dynamic model, the effects of temperature and concentration on the nucleation incubation time of Ni75AlxV25-x alloy were studied and the relation between the incubation time and precipitation mechanism was investigated by using the atomic occupation probability picture and average order parameter curve. The simulation results demonstrate that there exists the incubation time for different precipitation mechanisms~ such as non-classical nucleation, the mixed style of non-classical nucleation and spinodal decomposition, and spinodal ordering; and the incubation time shortens in turn for the three kinds of mechanisms. With the increase of Al content of Ni75AlxV25-x alloy, the incubation time of Llz phases shortens continuously and that of DOzz phases is prolonged. The effects of temperature on the incubation time of Llz and DOzz phases are accordant, i.e. the incuba- tion time is greatly prolonged with the temperature rising.

CFD-PBE simulation of a bubble column in OpenFOAM

A general CFD-PBE(computational fluid dynamics-population balance equation) solver for gas–liquid poly-dispersed flows of both low and high gas volume fractions is developed in OpenFOAM(open-source field operation and manipulation) in this work. Implementation of this solver in OpenFOAM is illustrated in detail. The PBE is solved with the cell average technique. The coupling between pressure and velocity is dealt with the transient PIMPLE algorithm, which is a merged PISO-SIMPLE(pressure implicit split operator-semi-implicit method for pressure-linked equations) algorithm. Results show generally good agreement with the published experimental data, whereas the modeling precision could be improved further with more sophisticated closure models for interfacial forces, the models for the bubble-induced turbulence and those for bubble coalescence and breakage.The results also indicate that the PBE could be solved out the PIMPLE loop to save much computation time while still preserving the time information on variables. This is important for CFD-PBE modeling of many actual gas–liquid problems, which are commonly high-turbulent flows with intrinsic transient and 3 D characteristics.

Contrast-enhanced ultrasound evaluation of hepatic microvascular changes in liver diseases

AIM： To assess if software assisted-contrast-enhanced ultrasonography （CEUS） provides reproducible perfu- sion parameters of hepatic parenchyma in patients af- fected by chronic liver disease. METHODS： Forty patients with chronic viral liver dis- ease, with （n = 20） or without （n = 20） cirrhosis, and 10 healthy subjects underwent CEUS and video re- cordings of each examination were then analysed with Esaote＇s Qontrast software. CEUS dedicated software Qontrast was used to determine peak （the maximum signal intensity）, time to peak （TTP）, region of blood value （RBV） proportional to the area under the time- intensity curve, mean transit time （MTT） measured in seconds and region of blood flow （RBF）. RESULTS： Qontrast-assisted CEUS parameters dis- played high inter-observer reproducibility （κ： coefficients of 0.87 for MTT and 0.90 TTP）. When the region of in-terest included a main hepatic vein, Qontrast-calculated TTP was significantly shorter in cirrhotic patients （vs non-cirrhotics and healthy subjects） （71.0 ± 11.3 s vs 82.4±15.6 s, 86.3±20.3 s, P 〈 0.05）. MTIs in the patients with liver cirrhosis were significantly shorter than those of controls （111.9±22.0 s vs 139.4±39.8 s, P 〈 0.05）, but there was no significant difference between the cirrhotic and non-cirrhotic groups （111.9± 22.0 s vs 110.3 ±14.6 s）. Peak enhancement in the patients with liver cirrhosis was also higher than that observed in controls （23.9± 5.9 vs 18.9±7.1, P = 0.05）. There were no significant intergroup differences in the RBVs and RBFs. CONCLUSION： Qontrast-assisted CEUS revealed re- producible differences in liver perfusion parameters during the development of hepatic fibrogenesis.

Numerical and Experimental Study on Droplet Spreading Motion after Impingement Considering Dynamic Contact Angle with CCUP （CIP-Combined Unified Procedure） Method

The contact angle is one of important parameters to simulate droplet spreading and impingement phenomena on the surface. In the most numerical research, it is assumed constant value and it is implemented as boundary condition. However, contact angle is changed according to contact line velocity and time. Hence, for accurate simulation, dynamic contact angle which has various values as time elapsed is adopted. In the present study, the numerical analysis is performed on the droplet spreading phenomena considering dynamic contact angle function which is obtained from single droplet spreading experiment on the flat and bare surface. The CIP （cubic interpolated pseudo-particle） method by Yabe is used for analysis of interface between liquid and gas phases. The numerical results considering contact angle function which newly modeled as time and contact angle are compared with numerical results considering Hoffman＇s function and experimental data for range of Weber number which are 4.427 and 11.334. In contrast of numerical result considering Hoffman＇s function, the numerical result shows good agreement with experimental data as time elapsed in contact angle evolution, deformation of droplet spreading radius and height. Indeed, overall, the results display the increasing maximum spreading radius and the decreasing height as Weber numbers increased.

Developing the s Factor

The current various proposals at the International Maritime Organisation （IMO） for the s factor （probability of surviving a given flooding） make no reference to survival time. The paper shows a direct link of the ＂prime＂ s factor with the time to capsize and shows how to utilise experimental data from 30-minute test runs for the s factor based on longer duration of tests. Unexpectedly, the extension of tests has a modest effect on the survival factor, and hence-modest effect on subdivision index A. Much more important is improving a deficient formulation for the required index R, as flooding cases with si = 1 have an infinite survival time.

Effects of Parameters in Femtosecond Laser Micromachining on Ablation of Silicon

A series of ablation experiments on silicon surface by femtosecond laser system of 775 nm and 150 fs duration pulses were carried out.The morphological characteristics and the associated effect in the ablation were tested by atomic force microscope(AFM),scanning electron microscope(SEM),focused ion beam(FIB),and the optic microscope.The single pulse threshold can be obtained directly.For the multiple pulses,the ablation threshold varies with the number of pulses applied to the surface due to the incubation effect.By analyzing the experimental data,the thresholds of laser fluences under various laser pulse numbers were obtained,and the relationships between ablation area and laser energy and laser pulse number were concluded.Meanwhile,the periodic ripple structure on silicon surface was found.Under the condition of certain laser power,the number of laser pulse can influence the formation of ripples.

Observations and analysis of environment and acoustic field changed by the passage of typhoon Damrey in the Yellow Sea in 2012

In order to investigate the environment and acoustic filed change induced by typhoon in shallow sea, we conducted two ex- periments just before and after the passage of typhoon Damrey, which is the strongest to affect the area north of the Yangtze River since 1949, in the Yellow sea in 2012. The data show that the temperature of the whole water column increases dramati- cally except the sea surface layer after the passage of Damrey while the salinity decreases obviously. The thermocline deepens and weakens, which leads to a change of internal wave activity. The transmission losses （TL） of the two experiments show that the environment change induced by typhoon can increase the TL as large as 8 dB at a distance of 9.2 km and depth of 15 m. The scintillation index （SI） of the sound intensity is simulated to estimate the change of the effect of internal wave activity on acoustic field showing that the SI decreases to a half after the typhoon＇s passage. The normal mode structures of the two experiments are also significanOy different due to the thermocline changes. In addition, the signal arrives earlier after the ty- phoon＇s passage due to the water temperature increase.

Lie Symmetries,Conservation Laws and Explicit Solutions for Time Fractional Rosenau–Haynam Equation

Under investigation in this paper is the invariance properties of the time fractional Rosenau-Haynam equation, which can be used to describe the formation of patterns in liquid drops. By using the Lie group analysis method, the vector fields and symmetry reductions of the equation are derived, respectively. Moreover, based on the power series theory, a kind of explicit power series solutions for the equation are well constructed with a detailed derivation. Finally, by using the new conservation theorem, two kinds of conservation laws of the equation are well constructed with a detailed derivation.

MAXIMUM POPULATION SIZES IN HOST-PARASITOID MODELS

We are concerned with the problem of characterizing the distribution of the maximum number of individuals alive during a fixed time interval in host-parasitoid models, which is shown to have a matrix exponential form. We present simple conditions on the rates of change of population sizes for the matrix exponential solution to be explicit or algo- rithmically tractable. A particularly appealing feature of our solution based on splitting methods is that it allows us to obtain global error control.

STABILITY ANALYSIS OF A PREDATOR-PREY MODEL

In this paper, a time-delayed predator-prey system is considered. The existence of Hopf bifurcations at the positive equilibrium is established by analyzing the distribution of the characteristic values. An explicit algorithm for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form and the center manifold theory. Numerical simulations to support the analytical conclusions are carried out.