软件工具的可视化力在物理教学中的应用

力是物理学的核心概念,Algodoo软件的“可视化力”功能能让我们直观地观察到物体的受力情况及其变化,为物理教学的直观化提供了辅助。在讲解静力学时,涉及到弹力、摩擦力和共点力的合成问题时,可以借助“可视化力”功能创设情境来研究问题;在与力相关的习题教学中,可以用“可视化力”功能来模拟情境,既能显示物体的受力情况,还能显示其运动情境;在破解一些教学难点时,“可视化力”功能会助一臂之力,如静摩擦力的凸凹齿合说等。我们建议,教师要熟悉Algodoo软件的功能、特点和使用方法,在教学中根据需要制作能解决实际问题的优秀课件,提高教学效益。

可视化领导力最佳实践

运用"三力合一"的思维驻点和"管理模型"的工具体系,直观、快捷、系统地分析和处理企业实战中遇到的问题。可视化领导力运用"三力合一"的思维驻点和"管理模型"的工具体系,直观、快捷、系统地分析和处理企业实战中遇到的问题。在为企业带来一种新理念的同时,也为思考和解决问题提供一种新的思维模式和工具体系。可视化领导力有两个构成要件,分别是"管理模型"的直观图像和"三力合一"的固化思维。

Algodoo软件在力的可视化教学中的应用

Algodoo软件是一款可以实现多种场景仿真的模拟软件,它能够可视化物体受到的力。针对判断力的有无、判断力的方向和判断运动物体受力情况这三种常见题型,利用力的可视化功能来进行力的教学能够给学生提供大量直观的感性认识,帮助学生建构相关物理知识。

Sentiment classification model for bullet screen based on self-attention mechanism

With the development of short video industry,video and bullet screen have become important ways to spread public opinions.Public attitudes can be timely obtained through emotional analysis on bullet screen,which can also reduce difficulties in management of online public opinions.A convolutional neural network model based on multi-head attention is proposed to solve the problem of how to effectively model relations among words and identify key words in emotion classification tasks with short text contents and lack of complete context information.Firstly,encode word positions so that order information of input sequences can be used by the model.Secondly,use a multi-head attention mechanism to obtain semantic expressions in different subspaces,effectively capture internal relevance and enhance dependent relationships among words,as well as highlight emotional weights of key emotional words.Then a dilated convolution is used to increase the receptive field and extract more features.On this basis,the above multi-attention mechanism is combined with a convolutional neural network to model and analyze the seven emotional categories of bullet screens.Testing from perspectives of model and dataset,experimental results can validate effectiveness of our approach.Finally,emotions of bullet screens are visualized to provide data supports for hot event controls and other fields.

Visualization of Bubble Dynamics for Pool Boiling of Binary Refrigerant Mixture R11-R113

A digital photographic study of pool boiling with binary mixture Rll（CC13）-Rll3（CCl3CF3） was performed on a horizontal transparent heater at pressure of 0.1MPa. A high speed digital camera was applied to record the bubble behaviors in boiling process. Strong effects of composition on bubble departure diameter, deparatre time, nucleation density were observed, which was attributed to the nature of the activation of the boiling surface and mass diffusion effects. The bubble departure diameter, departure period and nucleation density as functions of composition for binary mixtures R 11-R 113 were presented respectively. From the video images, it can be concluded that evaporation of microlayer is very important to the growth of bubble. It is also observed that there is not any liquid recruited into the microlayer below the bubble.

The Power of Reality： How Radio Documents Stimulate Listeners＇ Imagination and Emotions？

Sound has great power to move listeners＇ imagination and stimulate listeners＇ emotions. Sound makes the imagination work, and mind creates a sequence of associations, obvious and surprising, but always interesting. The sound is strength because of its delicacy. Because it does not create images, it evokes creativity. We see a picture, we even feel its movement. The sound＇s power of stimulating our imagination is known by the feature makers who-as John Biewen claims-use sound to tell story artfully. The author presents a visualization of sound, paying attention to a few aspects of this visualization, such as using a microphone like a camera, the role of pause/silence as photographs, audioscenography, and suggestiveness of human voice.

Unique influences of reboiler inventory control on the operation of totally reboiled reactive distillation columns

In this work,the dynamics and operation of the totally reboiled reactive distillation columns are visualized in terms of transfer function based process models.This kind of processes is found to be characterized by underdamped step responses due to the special topological configuration and the intricate interplay between the reaction operation and the separation operation involved.The under-dampness can be substantially alleviated through the tight inventory control of bottom reboiler and this presents beneficial effects to process dynamics and operation.Two totally reboiled reactive distillation columns,separating,respectively,a hypothetical synthesis reaction from reactants A and B to product C,and a real decomposition reaction from 1,4-butanediol to tetrahydrofuran and water,are employed to demonstrate these uncommon behaviors.The results obtained give full support to the above qualitative interpretation.Despite the strong influences of reaction kinetics and thermodynamic properties of the reacting mixtures,the totally reboiled reactive distillation columns are generally considered to present such unique behaviors and require tight inventory control of bottom reboiler to facilitate their control system development.

Generation of 3D random meso-structure of soil-rock mixture and its meso-structural mechanics based on numerical tests

The mesoscopic failure mechanism and the macro-mechanical characteristics of soil-rock mixture(S-RM) under external load are largely controlled by S-RM's meso-structural features. The objective of this work is to improve the three-dimensional technology for the generation of the random meso-structural models of S-RM, for randomly generating irregular rock blocks in S-RM with different shapes, sizes, and distributions according to the characteristics of the rock blocks' size distribution. Based on the new improved technology, a software system named as R-SRM3 D for generation and visualization of S-RM is developed. Using R-SRM3 D, a three-dimensional meso-structural model of S-RM is generated and used to study the meso-mechanical behavior through a series of true-triaxial numerical tests. From the numerical tests, the following conclusions are obtained. The meso-stress field of S-RM is influenced by the distribution of the internal rock blocks, and the macro-mechanical characteristics of S-RM are anisotropic in 3D; the intermediate principal stress and the soil-rock interface properties have significant influence on the macro strength of S-RM.

Study on conditions of internally carried air-launched launch vehicles based on the virtual prototype technology

A method based on the virtual prototype technology simulating the separation of a launch vehicle from its aircraft in the aircraft wake was proposed based on the internally carried air-launched launch vehicle program.In this method,the full-scale model of the aircraft,the vehicle and the parachute are constructed.Then,they are imported into the ADAMS software,constraint solutions and driving forces are then added for visual dynamic simulation.The unsteady aerodynamic forces of the vehicle in the aircraft wake are calculated by CFD and the moving grid technique.The forces generated by the parachute can be derived from the Kirchhoff motion equation.Through comparing and analyzing the simulation results under different launch conditions,it has been proven that this method simulates the separation of a launch vehicle from the aircraft in the aircraft wake accurately.It provides the foundation for the aggregate project of internally carried air-launch vehicles,and offers a new referenced method for multi-body dynamic simulation.

基于支架-围岩耦合原理的模拟试验液压支架及测控系统研制与应用

目前模拟试验中支架–围岩不能很好地满足强度、刚度和稳定性耦合关系,支架的多维受力特征也被忽略。为了保证试验结果的准确性和科学性,建立支架三维受力力学模型,考虑邻架挤压力和架尾推力对支架的影响,在满足支架结构稳定和受力环境与现场支架相似的基础上,借助高精度应力/位移传感器实时获取了模型支架工作参数,研制模拟试验液压支架及测控系统,测试成套系统的性能,结果表明:两柱掩护式模型支架阻力范围0.046~0.528 k N,可以通过调整液压系统油压输出端压力和立柱内径实现额定工作阻力的输出;支架增阻阶段刚度基本不变,且承载动压冲击的能力较强;支架临界下滑角在三向受力下比单向压缩时要小,抗滑能力下降,但架间挤压力与架尾推力在一定程度上又抑制了其倾倒的发生。将模型支架应用于绿水洞煤矿3132工作面开采试验中,支架的工作阻力为22.42 MPa,与实测结果误差在5%以内。对采空区进行探测,模型支架与现场支架在调整围岩结构和应力场方面效能一致。

Visualization Investigation on Flowing Condensation in Horizontal Small Channels with Liquid Separator

A simultaneous visualization and measurement experiment was carried out to investigate condensation flow pat- terns and condensing heat transfer characteristics of refrigerant R14 lb in parallel horizontal multi-channels with liquid-vapor separator. The hydraulic diameter of each channel was 1.5 mm and the channel length was 100 ram. The refrigerant vapor flowing in the small channels was cooled by cooling water. The parallel horizontal mul- ti-channels were covered with a transparent silica glass for visualization of flow patterns. Experiments were per- formed at different inlet superheat temperatures （ranging from 3~C to 7~C）. Mass velocity was in the range of 82.37 kg mZs1 to 35.56 kg m-2s1. It was found that there were three different flow patterns through the mul- ti-channels with the increase of mass velocity. The flow patterns in each channel pass almost tended to be same and all of them were annular flows.＇ The efficiency of the liquid-vapor separator with U-type was related to vapor mass velocity and the pressure in the small channels. It was also found that the heat transfer coefficient increased with the increase of the mass velocity while the cooling water mass flow rate increased. It increased to a top point and then decreased. It increased with the increase of superheat in the low superheat temperature region.

High-Speed Visualization of Bubble Behaviors for Pool Boiling of R-141b

A visualization study on the behavior of bubbles has been carried out for pool boiling of R141b on a horizontal transparent heater at pressure 0.1 MPa. The behaviors of bubbles were recorded by a high-speed camera placed beneath the heater surface. The departure diameter, departure time of bubbles and nucleation site density at different heat flux were obtained. The visualization results show that bubble departure diameter and departure time decrease, while the nucleation site density increases as the heat flux increases. R is also observed that there is no liquid recruited into the microlayer in the experiment. Based on the experimental results, boiling curve for R141b was predicted by using the dynamic microlayer model. As a resuR, the agreement between the predictive result based on the dynamic microlayer model and the experiment data for boiling curve of R141b is good at high heat flux.

Temperature and Pressure Measurements at Cold Exit of Counter-flow Vortex Tube with Flow Visualization of Reversed Flow

In order to clarify the structure of the cold flow discharged from the counter-flow vortex tube(VT), the temperature and pressure of the cold flow were measured, and the existence and behavior of the reversed flow at the cold exit was studied using a simple flow visualization technique consisting of a 0.75mm-diameter needle, and an oil paint droplet. It is observed through this experiment that the Pitot pressure at the cold exit center can either be lower or higher than atmospheric pressure, depending on the inlet pressure and the cold fraction, and that a reversed flow is observed when the Pitot pressure at the cold exit center is lower than atmospheric pressure. In addition, it is observed that when reducing the cold fraction from unity at any arbitrary inlet pressure, the region of reversed and colder flow in the central part of cold exit extends in the downstream direction.

Visualization of α_1-adrenergic receptors with phenylpiperazine-based fluorescent probes

Several novel fluorescent probes targeting α_1-adrenergic receptors were well designed and synthesized by conjugating phenylpiperazine pharmacophore with coumarin and fluorescein fluorophores. These compounds showed suitable fluorescence property, high receptor affinity, and low cytotoxicity. Moreover, the cell imaging results displayed that these probes can be effective tools for the real-time detection of ligand-receptor interactions, as well as the visualization and location of α_1-adrenergic receptors in living cells.