模内层压模具动态温度控制系统的设计实现

介绍一种模内层压注塑模具的动态温度控制系统,系统基于CPLD、FPGA构建了可靠、独立和快速的测控平台,并通过优化的PID策略,实现了模温的精确测量与控制。模内层压注塑工艺采用动态温度控制,提高了产品品质和生产效率。

变模温注塑技术的研究与应用分析

变模温注塑是一种基于动态模温控制策略的注射成型技术,可根据不同工艺阶段的特点,随时调整模具温度,可在不降低生产效率的同时有效提升塑件的品质。在深入回顾变模温注塑技术研究发展的基础上,分析比较各种技术的优缺点和应用范围。构建了蒸汽辅助加热变模温注塑系统,实现了平板电视机面板的高光无熔痕注塑生产。

蒸气辅助快速热循环注塑技术及模温响应模拟

快速热循环注塑采用动态模温控制新策略,可以彻底解决常规注塑工艺存在的短射、喷射痕、缩痕、流动痕、熔接痕、浮纤等缺陷。文中通过对快速热循环注塑工艺与常规注塑工艺的比较,深入研究了蒸气辅助快速热循环注塑工艺的原理,制定了相应的工艺流程,提出了一套新的利用蒸气加热和冷凝水冷却的动态模温控制方案。利用ANSYS模拟了快速热循环注塑工艺和常规注塑工艺的模温响应过程,分别获得了两种注塑工艺的模具加热速率和冷却速率,讨论了快速热循环注塑对塑件成型周期的影响规律。

基于Moldflow与Fluent模拟流体对注塑模温的热响应研究

以螺纹转接头注塑模为例,通过应用Moldflow与Fluent创建不同工况下的注塑模型,模拟动态模温模具的加热和冷却,分析流体类别及流速对模具温度变化的影响,获取动态模温注塑热响应曲线。结果显示:冷却流体流速对模温的影响有明显的区间差异性;模具型腔表面温度变化幅度比成型件内大,加热介质为热水时更显著;介质流速快的平均模温比流速慢的高,其中传热油特别明显;同一介质加热温度越高,加热及冷却时的模温变化幅度越大;加热介质对模温变化影响存在滞后性,其中传热油更明显。

石墨烯镀层辅助快速热循环注射成型方法的研究

提出了一种以石墨烯纳米镀层辅助实现快速热循环注射成型的新方法,采用化学气相沉积工艺在模具型腔表面制备连续且致密的化学键合石墨烯镀层,仅需低压电源驱动就能将型腔表面温度迅速提升至聚合物材料玻璃化转变温度(T_g)之上并进行实时调控,型腔表面温度分布均匀且具有较高的降温速率,可满足注射成型快变模温调控的要求。结果表明,利用石墨烯镀层快速热循环注射成型方法可有效改善注射成型熔体流动行为,明显消除制品的熔接痕。

快速热循环注塑技术的研究与应用

研究了一种新颖的快速热循环(高光无熔痕)注塑过程的工艺原理,建立了高光无熔痕注塑工艺流程;提出了一种利用蒸汽加热、冷凝水冷却的模具温度动态控制方法,自主研制了以PLC为控制核心的温度控制系统,并开发了相应的控制软件,实现了注塑模具温度的快速准确实时控制;利用人机界面技术,实现了注塑工艺全过程的实时监控,可保障生产系统的稳定性、可靠性和易操作性;建立了高光无熔痕绿色注塑生产线,实现了大型液晶平板电视机面板的绿色注塑生产,塑件表面无熔痕、流痕、凹陷等缺陷,达到镜面效果,无需环境污染严重的喷涂工艺等二次加工过程。

A Thermal-Conscious Integrated Circuit Power Model and Its Impact on Dynamic Voltage Scaling Techniques

We propose a novel thermal-conscious power model for integrated circuits that can accurately predict power and temperature under voltage scaling. Experimental results show that the leakage power consumption is underestimated by 52 % if thermal effects are omitted. Furthermore, an inconsistency arises when energy and temperature are simultaneously optimized by dynamic voltage scaling. Temperature is a limiting factor for future integrated circuits,and the thermal optimization approach can attain a temperature reduction of up to 12℃ with less than 1.8% energy penalty compared with the energy optimization one.

Ant colony system algorithm for the optimization of beer fermentation control

Beer fermentation is a dynamic process that must be guided along a temperature profile to obtain the desired results. Ant colony system algorithm was applied to optimize the kinetic model of this process. During a fixed period of fermentation time, a series of different temperature profiles of the mixture were constructed. An optimal one was chosen at last. Optimal temperature profile maximized the final ethanol production and minimized the byproducts concentration and spoilage risk. The satisfactory results obtained did not require much computation effort.

Molecular Dynamics Simulations for Melting Temperatures of SrF2 and BaF2

The shell-model molecular dynamics method was applied to simulate the melting temper- atures of SrF2 and BaF2 at elevated temperatures and high pressures. The same method was used to calculate the equations of state for SrF2 and BaF2 over the pressure range of 0.1 MPa-3 GPa and 0.1 MPa-7 GPa. Compared with previous results for equations of state, the maximum errors are 0.3% and 2.2%, respectively. Considering the pre-melting in the fluorite-type crystals, we made the necessary corrections for the simulated melting temper- atures of SrF2 and BaF2. Consequently, the melting temperatures of SrF2 and BaF2 were obtained for high pressures. The melting temperatures of SrF2 and BaF2 that were obtained by the simulation are in good agreement with available experimental data.

A study on the characterization of smoke movement in shafts with different fire source positions

In this study,experimental and numerical simulation methods were combined to simulate the changing course of the temperature and velocity fields in nine different fire scenes. The characteristics of smoke movement in shafts with different fire source position factors(h/H) were quantitatively investigated,and the non-dimensional fitting function between the fire source position factors and the maximum temperature was deduced. The results showed that the location of the neutral plane moved upward as the fire source rose,and all the generated smoke spread to the upper areas;however,there was barely any smoke in the lower areas. The maximum temperature was inversely proportional to the fire source position factor;the higher the source position is,i.e. the higher the ratio factor is,the lower the maximum temperature is in the shaft. The experimental verification of the fire dynamics simulator(FDS) showed good results.

Optimal dynamic dispatch of surplus gas among buffer boilers in steel plant

As valuable energy in iron-and steel-making process,by-product gas is widely used in heating and technical processes in steel plant.After being used according to the technical requirements,the surplus by-product gas is usually used for buffer boilers to produce steam.With the rapid development of energy conservation technology and energy consumption level,surplus gas in steel plant continues to get larger.Therefore,it is significant to organize surplus gas among buffer boilers.A dynamic programming model of that issue was established in this work,considering the ramp rate constraint of boilers and the influences of setting gasholders.Then a case study was done.It is shown that dynamic programming dispatch gets more steam generation and less specific gas consumption compared with current proportionate dispatch depending on nominal capacities of boilers.The ignored boiler ramp rate constraint was considered and its contribution to the result validity was pointed out.Finally,the significance of setting gasholders was studied.

Alternate Form of Damped Wave Conduction and Relaxation Equation a Capite Adcalcem in Temperature

An alternate non-Fourier heat conduction equation is derived from consideration of translation motion of spinless electron under a driving force due to an applied temperature gradient. This equation is a eapite ad calcem,temperature. Elimination of the rate of change of velocity with respect to time leads to a non-Fourier heat conduction equation with a accumulation of temperature or ballistic term in it. The new constitutive heat conduction equation is combined with the energy balance equation in one dimension. The governing equation for transient temperature a partial differential equation （Eq. （23）） is solved for by the method of Laplace transforms. The problem considered is the semi-infinite medium with constant thermo physical properties with constant wall temperature boundary condition. A closed form analyticalexpression for the transient temperature was obtained （Eq. （36）） after truncation of higher order terms in the infinite binomial series and use of convolution and lag properties. This solution is compared with that obtained using the parabolic Fourier model and the damped wave model as presented in an earlier study. The predictions of Eq. （36） are closer to the Fourier model. The convex nature of the temperature curve is present.

A statistical dynamics model of the marine ecosystem and its application in Jiaozhou Bay

Models of marine ecosystem dynamics play an important role in revealing the evolution mechanisms of marine ecosystems and in forecasting their future changes. Most traditional ecological dynamics models are established based on basic physical and biological laws, and have obvious dynamic characteristics and ecological significance. However, they are not flexible enough for the variability of environment conditions and ecological processes found in offshore marine areas, where it is often difficult to obtain parameters for the model, and the precision of the model is often low. In this paper, a new modeling method is introduced, which aims to establish an evolution model of marine ecosystems by coupling statistics with differential dynamics. Firstly, we outline the basic concept and method of inverse modeling of marine ecosystems. Then we set up a statistical dynamics model of marine ecosystems evolution according to annual ecological observation data from Jiaozhou Bay. This was done under the forcing conditions of sea surface temperature and surface irradiance and considering the state variables of phytoplankton, zooplankton and nutrients. This model is dynamic, makes the best of field observation data, and the average predicted precision can reach 90% or higher. A simpler model can be easily obtained through eliminating the terms with smaller contributions according to the weight coefficients of model differential items. The method proposed in this paper avoids the difficulties of obtaining and optimizing parameters, which exist in traditional research, and it provides a new path for research of marine ecological dynamics.

What Determines the Amplitude of ENSO Events?

In this paper, the dynamic effect of oceanic upwelling on the intensity of E1 Nifio-Southern Oscilla tion （ENSO） is studied using a simple coupled model （Zebiak-Cane Model）. The term balance analysis in the temperature variability equation shows that the anomalous upwelling of the mean vertical temperature gradient and the mean advection of the anomalous meridional tem perature gradient are the two of most important factors that determine the intensity of ENSO events, in which the ＂vertical oceanic heat flux＂ in the eastern equatorial Pa cific （EEP） is the primary influencing factor. The lag cor relation between ＂vertical heat flux （VHF）＂ and ENSO intensity shows that the highest correlation occurs when the former leads the latter by one to two weeks. The VHF is positively correlated with the background thermocline strength in the EEP, and an increase of both could result in strong ENSO variability. Comparison of the forced and coupled experiments suggests that the coupled process can affect both the intensity and freauencv of ENSO.

Alpine Activity Patterns of Mitopus morio(Fabricius, 1779) are Induced by Variations in Temperature and Humidity at Different Scales in Central Norway

Our research addresses questions about how micro-climate affects activity abundance of a common and widespread harvestman in an alpine ecosystem. Activity patterns of the Harvestman Mitopus morio(Fabricius, 1779) were studied along different alpine gradients in the central Norwegian Scandes. Within a nested design, we surveyed 18 alpine habitats with pitfall traps and microclimatological equipment along oceanic-continental, two elevational, and(fine-scaled) microtopographic gradients. Sites in the oceanic region of the Scandes showed generally higher abundance of M. morio than sites in the continental region. Furthermore, along the elevational gradient, middle-alpine sites showed higher abundances than low-alpine sites. These general patterns are best explained by higher humidity in the oceanic region and in the middlealpine belt. Focusing at a finer scale, i.e. one elevational level within each region, revealed partly opposing activity patterns within relatively short distances. While in the western middle-alpine belt these patterns were best explained by humidityrelated measures but now with higher activity abundance during drier conditions, in the drier eastern middle-alpine belt heat sums rather than humidity were found to be the best explanatoryvariables for the observed patterns. Hence, our results imply a pronounced different reaction of the two populations towards climatic variables that partly even contradict the previously described general pattern. Regardless whether these differences in activity abundance in M. morio are a form of phenotypic plasticity or adaptation, our findings stress the importance of detailed autecological knowledge combined with fine-scaled climatic measurements when aiming at predictions about possible future ecosystem structures and spatiotemporal phenomena. M. morio proves to be an ideal biogeographic model organism for understanding spatio-temporal responses of alpine ecosystems under modified climatic conditions.

快速热循环工艺对玻纤增强注塑制品表面质量的影响研究

提出将快速热循环方法辅助注塑成型工艺,探究不同型腔温度对薄壁玻纤增强制品的表面质量的改善情况。结果表明:制品表面光泽度随着型腔温度的升高也有所提高,表面的"浮纤"缺陷得到明显的改善,但是制品表面粗糙度则随着型腔温度的升高而增大。通过提高型腔表面质量的同时辅助快速热循环工艺,可以明显改善制品的表面质量。