Thermodynamic Calculation on the Formation of Titanium Hydride

A modified Miedema model, using interrelationship among the basic properties of elements Ti and H, is employed to calculate the standard enthalpy of formation of titanium hydride TiHx (1≤x≤2). Based on Debye theories of solid thermal capacity, the vibrational entropy, as well as electronic entropy, is acquired by quantum mechanics and statistic thermodynamics methods, and a new approach is presented to calculate the standard entropy of formation of TiH2. The values of standard enthalpy of formation of TiHx decrease linearly with increase of x. The calculated results of standard enthalpy, entropy, and free energy of formation of TiH2 at 298.16 K are -142.39 kJ/mol, -143.0 J/(mol?K) and -99.75 kJ/mol, respectively, which is consistent with the previously-reported data obtained by either experimental or theoretic     

基于虚拟现实技术的电机的虚拟运行

介绍和分析了虚拟现实技术,提出了基于3DS MAX和VRML的产品网上三维虚拟的展示方法.以典型的三相绕线式异步电动机为对象,基于面向对象的方法来描述其基本结构、主要部件的几何特征、运动特性和功能特点,运用3DS MAX对其进行三维建模、建立其虚拟展示的场景模型,并结合VRML的虚拟交互技术和外部编程接口技术EAI对已建立起来的电动机虚拟场景进行交互式虚拟操作.在此基础上,构建了基于VRML的电动机运行状态模拟的网上展示系统,使得用户可基于Web的互动方式远程、透明地访问、浏览、观看和了解该设备不同视觉角度的三维结构、动画演示、主要特征等.     

基于Petri网的报社稿件管理系统建模与实现

为了管理来自网络的大量稿源信息,需要对稿件进行数字化、集成化的管理。本文针对报社稿件管理的数字化、网络化和自动化等问题,结合petri网理论和工作流技术,提出了一个适用于稿件审核的新的工作流网——MMWFN（稿件管理系统工作流网）,并对报社稿件审核工作流程进行建模,同时通过对系统的功能需求和模块体系结构的详细分析,使用动态网页技术,设计和实现了报社稿件管理系统。     

建筑火灾区域模拟辐射换热的计算

首先给出了几个与区域模拟基本思想相一致的假设，然后据此推导了区域模拟辐射换热的计算模型．本模型将火源假设为点火源；并假定包壳仅由两个表面组成，其中，上表面为顶篷和上部坚墙，而下表面为地板和下部竖墙．这一模型既考虑了吸收性介质对火源及壁面辐射的影响，也考虑了烟气主要成份对吸收性系数的影响．     

基于Petri网的遥感卫星业务运行管理单元模型设计与仿真

本文首先介绍了Petri网和四种工作流原语向Petri网映射的方法及其性能分析算法;然后通过研究遥感卫星业务运行管理单元的业务运行流程,实现了基于Petri网对遥感卫星业务运行管理单元常规模式和应急模式的工作流程的层次化建模;最后利用Petri网仿真软件Visual Object Net 对常规模式和应急模式的工作流程进行仿真并分析其时间性能。仿真结果表明本文所建立的基于Petri网的工作流模型是正确的,并且业务运行流程在采用应急模式时,业务运行管理单元节省了大约60%的系统运行时间,故该模型运行效果良好。     

基于UC3854的Boost电路的仿真与应用

有源功率因数校正技术对解决电源污染问题有着重要意义。本文引入建模分析法和状态空间法研究一种平均电流控制模式的Boost型功率因数校正技术,分析Boost变换器各个环节的电压、电流的变化情况,推导其状态方程,建立了Boost变换器的MATLAB仿真模型,并利用UC3854控制芯片,设计出一个基于平均电流控制模式的功率因数校正实验装置。仿真与实验结果的一致性表明该模型是有效的。     

计算机图形学中图素的面向对象描述与存储

为降低软件开发的复杂度，提高软件开发的质量和可重用性，运用面向对象建模方法对计算机图形学中的图素进行了对象化分类与描述；同时，针对目前许多图形系统的数据模型在计算机内部表示上普遍存在不兼容，彼此间难以进行图形数据变换与共享的问题，提出了运用关系数据库存储图形数据，给出UML(Unified Modeling Language)模型向E-R(Entity Relationship)模型映射的方法，将对象建模过程中生成的图形数据存储到关系数据库中。该方法不仅为图形数据的存储提供了有效途径，同时使各种图形数据转换在关系数据库的基础上具有统一的标准。     

Hyperelastic modeling of location-dependent human distal femoral cartilage mechanics

Knee articular cartilage exhibits complex mechanical behavior, even under high strain rates, which poses a challenge to developing accurate and efficient cartilage models. In particular, the tissue׳s stress–strain response is non-linear and the stiffness of the response is location-dependent. Hyperelastic models such as those of Alan Gent and others have increasingly found use in soft tissue biomechanics. Recently, a hyperelastic statistical chain network model representing the transverse isotropy of the collagen matrix in the superficial tangential zone has been developed. The model successfully simulated the 100% strain/s unconfined compression response of human proximal tibial cartilage. Moreover, spatial variations in the tangent modulus to the nominal stress–strain curve taken at 10% strain were reflected in the variability of a single parameter of the model. Given the success of the model, we desired to determine whether these outcomes are equally applicable to healthy human distal femoral cartilage so that a complete model of tibiofemoral joint cartilage can be developed. The transversely isotropic model was employed along with two other hyperelastic chain network models to determine which model best simulated unconfined compression data for healthy distal femoral cartilage. The transversely isotropic model fit the data excellently (R²=0.999). The model was subsequently simplified to depend on a single parameter and reapplied to the dataset. The modified model maintained an excellent fit to the data (R²=0.999), and its single parameter varied in a statistically similar regional pattern (p<0.05) to the experimentally-obtained elastic modulus of the tissue. Outcomes suggest that this model is suitable for modeling the spatially-varying, non-linear mechanics of healthy human distal femoral cartilage. Implementation of this constitutive relation within computational models of the knee will provide novel insight into the relationship between joint mechanics, cartilage loading, and knee osteoarthritis development.     

Machine learning simulation of pharmaceutical solubility in supercritical carbon dioxide: Prediction and experimental validation for busulfan drug

An artificial intelligence-based predictive model was developed using a support vector machine to investigate the solubility data of the drug Busulfan drug in supercritical carbon dioxide. The data for simulations were collected from literature. The model was trained and implemented in order to determine the correlation between the solubility values and the input parameters, namely, temperature and pressure. These parameters were used as the inputs as they are known to have a significant effect on the solubility of Busulfan in supercritical carbon dioxide. In the artificial intelligence model, a polynomial model with kernel function was applied to the data, and the model’s findings were compared with measured data for fitting. Good agreement was observed between the model’s outputs and the measured data with coefficient of determination greater than 0.99.