Environmental Simulation Experiments of 3D-C/SiC Composites with Different PyC Interfacial Layers

A series of 3D-C/SiC composites with different pyrolytic carbon (PyC) interracial layers (about 20～300 nm thick)were prepared by chemical vapor infiltration. Simulation experiments at different temperatures were performed byexposing C/SiC specimens in single and coupling gases partial pressure atmospheres, namely, O2, H2O vapor andmolten salt (Na+) vapor. It suggested that at intermediate temperature range (about 600～800℃) a dramatic effectof PyC thickness on the weight and strength change of C/SiC was shown, which was mainly influenced by O2 partialpressure; at high temperature range (about 1200～1300℃) the effect was not obvious relatively, which might beinfluenced by H2O vapor partial pressure; and finally at very high temperature range (＞1500℃) the molten saltvapor was the factor of most possibility affecting the weight change of C/SiC.

Kinetic Model and Simulation Analysis for Toluene Disproportionation and C9-Aromatics Transalkylation

A new kinetic model for commercial unit of toluene disproportionation and C9-armatiocs transalkylation is developed based on the reported reaction scheme.A time based catalyst deactivation function taking weight hourly space velocity(WHSV)into account is incorporated into the model,which reasonably accounts for the loss in activity because of coke deposition on the surface of catalyst during long-term operation.The kinetic parameters are benchmarked with several sets of balanced plant data and estimated by the differential variable metric optimiza- tion method.Sets of plant data at different operating conditions are applied to make sure validation of the model and the results show a good agreement between the model predictions and plant observations.The simulation analysis of key variables such as temperature and WHSV affecting process performance is discussed in detail,giv- ing the guidance to select suitable operating conditions.

J^(#)-U_(c)-clean环与强J^(#)-U_(c)-clean环

设R是一个环,如果U(R)=U_(c)(R)+J^(#)(R),则称R是GU_(c)J环;如果对于任意a∈R,都存在g∈U_(c)(R),p^(2)=p∈R,d∈J^(#)(R)使得ag=p+d(且ap=pa),则称R是(强)J^(#)-U_(c)-clean环。GU_(c)J环和J^(#)-U_(c)-clean环分别是GUJ环和GJ-clean环的真推广。文章研究了GU_(c)J环的基本性质,证明了R是GU_(c)J环当且仅当R/J是U_(c)U环且U_(c)(R/J)=(U_(c)(R)+J)/J,R是U_(c)J环当且仅当R是GU_(c)J环且R/J是reduced的。此外,给出了(强)J^(#)-U_(c)-clean环的例子,得到了(强)J^(#)-U_(c)-clean环的性质和一些等价刻画,证明了若R是一个交换环,则R是GJ-clean环当且仅当存在整数n≥1使得T_(n)(R)是GJ-clean环,当且仅当存在整数n≥2使得T_(n)(R)是J^(#)-U_(c)-clean环。进一步地,研究了强J^(#)-U_(c)-clean环的Morita不变性。

Temperature-triggered Protein Adsorption and Desorption on Temperature-responsive PNIPAAm-grafted-silica:Molecular Dynamics Simulation and Experimental Validation

Poly(N-isopropylacrylamide)(PNIPAAm) grafted onto silica,which may be used for reverse phase chromatography(RPC),was simulated and synthesized for protein separation with temperature-triggered adsorption and desorption.Molecular dynamics simulation at an all-atom level was performed to illustrate the adsorption/desorption behavior of cytochrome c,the model protein,on PNIPAAm-grafted-silica,a temperature responsive adsorbent.At a temperature above the lower critical solution temperature(LCST),the PNIPAAm chains aggregate on the silica surface,forming a hydrophobic surface that is favorable for the hydrophobic adsorption of cytochrome c,which has a high exposure of hydrophobic patches.At temperatures below the LCST,the PNIPAAm chains stretch,forming hydrophilic surface due to hydrogen bonding between PNIPAAm and surrounding water.Desorption of cytochrome c on the PNIPAAm-grafted-silica surface occurs as a result of competition with water,which forms hydrogen bonds with the protein.The conformational transitions of both cytochrome c and PNIPAAm are monitored,providing molecular insight into this temperature-responsive RPC technique.PNIPAAm-grafted-silica beads were synthesized and used for the adsorption and desorption of cytochrome c at approximately 313 K and 290 K,respectively.The experimental results validate the molecular dynamics simulation.In comparison to conventional RPC,using temperature as a driving force for RPC reduces the risk of protein denaturation caused by exposure to chaotropic solvents.Moreover,it simplifies the separation process by avoiding the buffer exchange operations between the steps.

Modeling and Simulation of Heat Transfer Phenomenon Related to Mold Heating during Investment Casting

Cast shape during investment casting process dictates properties and service life of the casting. These properties are the function of cast part parameters (both static and dynamic), part geometry and hence mold geometry, nature and type of metal being cast, properties (extrinsic and intrinsic) and processing parameters (rate of heating, rate of cooling, rate of pouring). Improper and inadequate manipulation and modification of mold properties degrade the properties and life of casting altogether. A mathematical model is developed using standard transport equations incorporating all heat transfer coefficients (HTCs) to determine the effect of external mold heating on the properties of the final casting and a simulation is performed in C++ to validate it against experimental results. Pure iron is casted in investment molds of silica sand with zircon coating. Airflow near the mold surfaces was partially restricted due to geometry of the molds and arrangement of the pieces around a tree. The variations in heat transfer coefficient contribute towards total heat transfer out of mold surface. External heating is found to be very effective for improved casting properties. The mold heat transfer profile is found to be in good agreement with experimental values validating the effectiveness of mold heating.

Design and simulation of a Torus topology for network on chip

Aiming at the applications of NOC （network on chip） technology in rising scale and complexity on chip systems, a Torus structure and corresponding route algorithm for NOC is proposed. This Torus structure improves traditional Torus topology and redefines the denotations of the routers. Through redefining the router denotations and changing the original router locations, the Torus structure for NOC application is reconstructed. On the basis of this structure, a dead-lock and live-lock free route algorithm is designed according to dimension increase. System C is used to implement this structure and the route algorithm is simulated. In the four different traffic patterns, average, hotspot 13%, hotspot 67% and transpose, the average delay and normalization throughput of this Torus structure are evaluated. Then, the performance of delay and throughput between this Torus and Mesh structure is compared. The results indicate that this Torus structure is more suitable for NOC applications.

Numerical Simulation of PRHR System Based on CFD

In this paper numerical simulation of PRHR HX and IRWST is demonstrated using FLUENT, and different numbers of C-type heat transfer tubes and coolant inlet temperature’s effects for the residual heat removal capacity of PRHR HX, IRWST thermal stratification and natural circulation have been researched. It’s found that at a constant flow area when heat transfer tubes’ number increased outlet temperature of PRHR HX is lower, the whole water temperature of IRWST is higher, thermal stratification and natural circulation are more oblivious. At a constant mass flow when inlet temperature of PRHR HX increased, inlet flow velocity increases and outlet temperature is higher. But on the other hand the cooling rate increases at the same time, the average temperature of IRWST is higher, the range of thermal stratification expands and the velocity of natural circulation increases.

Molecular Dynamics Simulation Study of CIF in Water： Halogen Bonding Interaction in Liquid

Does the halogen bonding interaction co-exist in liquid when it competes with the hydrogen bonding interaction？ The classical molecular dynamics simulations for the solvation properties of CLF molecule in water are performed with the Lennard-Jones plus Coulomb electrostatic potential parameters that are optimized with ab initio interaction energy calculations for the pre-reactive H2O-CLF complex. We find that the halogen bonding interactions occur between O and CL atoms and have the comparable strength and population with respect to the hydrogen bonding interactions of C1...H.

Study on the QSIM-based Simulation of the Credit Behavior in C2C E-commerce

As the behavior of breaking credit is more womed by people in C2C transactions, all state variables in the C2C transaction system of credit signal transmission mechanism and punishment mechanism may have many results after credit is cracked by seller. In this paper, the development and change trend of seller＇s credit behavior is studied by taking seller＇s behavior of cracking credit as the initial state. By a QSIM qualitative research, how the credit decision of an individual develops is found under the joint action of the credit mechanism, signal transmission mechanism, and punishment mechanism in C2C. Based on the research result, policy suggestions are proposed for the development of the online C2C credit mechanism.

Experimental Investigation to Establish the Possibility of Realistic Simulation of the Behavior of Single Storey—One Bay Infilled R.C.Frames in Scale 1:9,Subjected to Horizontal Cyclic Loading

In order to study the dynamic behaviour of construction,specifically seismic response of structures,as many researchers did,we have resorted to modelling methods,based on the scaled internal forces.Therefore,this research includes results of an experimental investigation aimed to establish the possibility of realistic simulations of the cyclic response of small-scale models of one bay,one-storey reinforced concrete frames with masonry infills as a preliminary step for simulating the dynamic response of such structural.So,the specimens constructed were 1:9 scale R/C frames.These 1:9 scale infill frames were constructed with prototype materials and were tested in an extensive experimental sequence representing specimens of a scale near the prototype(1:3).The tested laboratory models include 1:3 scale infilled R/C frames that were built from original material such as steel,concrete and masonry infills(hollow masonry units and mortar).With the same scale,geometry and construction materials used for the construction of a 1:3 scale 5-story three dimensional building.This program consisted of 16 models,5 bare and 11 masonry infilled.all models refer to single-storey one-bay 1:9 scale as for the original structure and a one third of the scale(1:3)as for the prototype(1:3).The reinforced concrete specimens were designed in such a way as to prevent shear failure of the columns.Finally,the present paper was carried out in the Laboratory of Strength of Materials and Structures in the Department of Civil Engineering at Aristotle University of Thessaloniki.

Simulation of Ceramic Grain Growth in Three Dimensions

Microstructural evolutions of ceramic grain growth at atomistic scale were modeled. The simulation was preceded with Monte-Carlo method, using Visual C++ and OpenGL languages. Realistic images in series were monitored both in two d imensions and three dimensions. Simulated image of grain growth in this series i s presented in left figure with N 0=25, r=0.40 nm, α=0.1, T=1 300 ℃, and P 0=50 %. It was seen that the average grain size increases wit h the time of grain growth. It is in good agreement with that of practical BST c eramics. The average grain area versus grain growth time is shown in right figur e. It is clear that the kinetic exponents of grain growth are not constant durin g the process of microstructural evolution. The kinetic exponents are smaller ( m≈0.5) at the early stages of growth and larger (m≈8) at the later sta ges, which are in agreement with reported results.

基于Simulink与C~#混合编程的交流传动试验仿真平台设计

介绍了Simulink与C#混合编程相关技术,叙述了交流传动试验仿真平台开发过程及界面设计特点,总结了设计中遇到的技术难点,并提出了有效解决方案。

CRYSTAL STRUCTURE OF A LONG－PERIOD ORDERED PHASE IN Fe－C MARTENSITE AND COMPUTER SIMULATION OF ITS ELECTRON DIFFRACTION PATTERNS

Different structure models of a long-period ordered phase in Fe-C martenstie formed during aging have been checked by computer simulation of electron diffraction(ED) patterns based on these models.The results showed that the simulated ED pattern of γ'-FexC(Ⅱ) model proposed by the present authors is in good agreement with experimentally observed ED pattern.It was also confirmed that the incommensurate superperiod stems from the coexistence of several γ'-Fe_xC(H) phases with different superperiods.The Fe(144)C(24)(Fe6C) model proposed by Uwakweh et al.generated ED patterns remarkably different from the experimental ones.

Numerical Simulation for Analysis and Optimization of the Elastic Properties of a C-spring Tube

In this paper we use the finite element analysis software ANSYS10.0 to establish a finite element model for pressure gauge C -spring tube, and the main factors affected the relation between the pressure and distortion displacement are analyzed. The results show that with the increasing of the spring tube wall thickness T and the minor axis length B, the elastic rigidity of spring tube increases, which is reduced with spring tube diameter D. Moreover, the major axis length H increases. Meanwhile, a pressure gauge spring tube has been optimized according to the simulation results bused on a model with special features, and the design results achieve the intended purpose. The analysis results provide a reliable method for the research and design of similar elastic elements.

气体分压比对2~#钢在H_2S/CO_2环境中腐蚀的影响

采用常温高压条件下的挂片试验,结合SEM和EDS等技术,研究了20#钢在H2S/CO2环境中不同气体分压比(pCO2/pH2S)条件下的腐蚀行为。结果表明,在试验环境中,20#钢的腐蚀以均匀腐蚀为主,伴有轻微的局部腐蚀;在低气体分压比情况下,腐蚀呈现先增大后减小再增大的规律;依据腐蚀规律,可将低分压比变化范围分为两个区域,在两个腐蚀区域内,腐蚀产物的元素百分含量差别不大,腐蚀产物以FeS和FeCO3为主。

Simulating leaf net CO_2 assimilation rate of C_3 & C_4 plants and its response to environmental factors

Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former researcher results. Then, considering some environmental factors influencing on leaf photosynthesis, three numerical sensitivity experiments were carried out. We simulated the sing le leaf net CO2 assimilation, which acts as a function of different light, carbo n dioxide and temperature conditions. The relationships between leaf net photosy nthetic rate of C3 and C4 plant with CO2 concentration intercellular, leaf tempe rature, and photosynthetic active radiation (PAR) were presented, respectively. The results show the numerical experiment may indicate the main characteristic o f plant photosynthesis in C3 and C4 plant, and further can be used to integrate with the regional climate model and act as land surface process scheme, and bett er understand the interaction between vegetation and atmosphere.

基于C#和DSP的核能谱模拟平台构建

针对核信号在脉冲幅度和相邻脉冲时间间隔上存在的随机性,探讨构建了一种基于C#和DSP软硬件的核能谱模拟平台。采用相关算法,产生核随机信号,并统计其涨落特性,在软硬件两方面实现对任意核能谱的精确模拟和逼真再现。可对相邻核信号产生的时间间隔作任意分布设定,还可对核能谱的刷新频率、每次刷新增加的脉冲数以及统计脉冲总数等参数进行设置。模拟结果表明,在统计的脉冲总数与原始数据量相等的情况下,谱各道相对误差可控制在0.5%以内。

基于C#与Viustools的物探虚拟实验系统及应用

目前地质院校物探专业教学中普遍存在学生数量与有限物探仪器的矛盾,给专业实验课和教学实习带来了困境。为了解决这个问题,应用C#,Viustools和数据库技术,较好地实现了物探仪器虚拟实验系统的设计,构建出高真实感的虚拟实验学习环境。投入教学应用后实践证明,利用虚拟实验方式去改革传统的实验教学模式,能够促进学生对实验设备和实验过程的理解和掌握,节约教学的时间和经费,提升教和学的效率,也便于教师进行针对性的教学,效果改善明显。

C#开发AutoCAD在盘形槽凸轮参数化绘制中的应用

针对绘图软件在绘制凸轮二维图的过程中所存在的周期长、效率低的问题,对AutoCAD软件的二次开发进行了相关研究。以盘形槽凸轮机构为例,运用Visual Studio2015开发工具,采用Visual C#语言对AutoCAD软件进行了二次开发,结合凸轮设计的原理,在Visual C#人机交互界面中输入了相关参数,完成了盘形槽凸轮的绘制,最后利用Solid Works软件对绘制出的以修正正弦为主运动曲线的盘形槽凸轮二维图进行了三维建模,以及运动仿真分析。研究结果表明:运用Visual C#对AutoCAD软件进行二次开发求取凸轮轮廓曲线的方法,能在够保证盘形槽凸轮轮廓曲线精度、缩短其绘图周期的前提下,实现盘型槽凸轮的参数化绘制。

基于OpenGL与C#的工业机器人三维仿真设计与实现

以6R机器人为对象,应用基于空间机构学理论建立其运动学方程,在Windows环境下,通过C#对OpenGL动态链接库函数的调用,建立机器人机械本体三维实体模型和实现各构件空间相对运动仿真,进而完成该机器人三维仿真软件设计.该方法具有低硬件要求和高动画仿真效果,且方便快捷,在其他应用场合也具有一定的参考意义.