一次引爆型云爆剂的爆速计算

以典型一次引爆型云爆剂为基础,根据炸药的热化学理论和爆轰理论,对一次引爆型云爆剂的爆速进行了理论分析和计算,并研究了组分配比及配方对爆速的影响.结果表明,一次引爆型云爆剂的理论爆速与金属粉含量有关,在一定范围内适当增加金属粉含量,可以提高爆速,且金属粉的热值越高,其一次引爆型云爆剂理论爆速也越高.     

Single Event Kinetic Modeling of Complex Catalytic Processes

Kinetic models for complex processes may contain an excessive number of rate parameters. Rather than simplifying the reaction scheme the approach illustrated here develops it in terms of the elementary steps of cation chemistry, using a computer algorithm. The resulting scheme, although gigantic, thus consists of a limited number of types of steps, generally involving series of homologous species. The rate coefficients of these steps are modeled based upon transition state theory and statistical thermodynamics. The single event concept explicits the effect of structure on the entropy contribution to the rate coefficient of the transformation, while the enthalpy effect is calculated using the Evans-Polanyi relation. Together with thermodynamic constraints this approach drastically reduces the number of independent parameters to be determined from the experimental data. The approach is applied to the methanol-to-olefins process on ZSM5 and to a process with complex feedstock like the catalytic cracking of vacuum gas oil. In the latter case an additional problem is the requirement of an adequate feedstock definition. Other processes catalyzed by acid catalysts, eventually loaded with metals, like hydrocracking, catalytic reforming, alkylation and, more generall, processes involving series of homologous components can be dealt with along the same lines.     

3‐D Simulations of an Internal Airlift Loop Reactor using a Steady Two‐Fluid Model

Three‐dimensional (3‐D) simulations of an internal airlift loop reactor in a cylindrical reference frame are presented, which are based on a two‐fluid model with a revised k‐? turbulence model for two‐phase bubbly flow. A steady state formulation is used with the purpose of time saving for cases with superficial gas velocity values as high as 0.12 m/s. Special 3‐D treatment of the boundary conditions at the axis is undertaken to allow asymmetric gas‐liquid flow. The simulation results are compared to the experimental data on average gas holdup, average liquid velocity in the riser and the downcomer, and good agreement is observed. The turbulent dispersion in the present two‐fluid model has a strong effect on the gas holdup distribution and wall‐peaking behavior is predicted. The CFD code developed has the potential to be applied as a tool for scaling up loop reactors.     

三维编织复合材料的力学行为研究现状

关于三维编织复合材料的细观几何模型以及力学性能的研究进展进行了综述,着重阐述了近年来该研究领域的一些学术成果,其中包括三维编织复合材料力学性能的实验和理论研究.实验研究则多以测试各种编织参数和载荷对其力学性能参数的影响规律,而理论研究则侧重介绍细观结构力学模型.最后,总结了目前研究工作存在的问题,并对未来发展趋势做出展望.     

Numerical Investigation of Perovskite and u-CIGS Based Tandem Solar Cells Using Silvaco TCAD Simulation

Silicon - In this paper, a numerical model is designed to evaluate the performances of a two-terminal tandem Perovskite-CIGS solar cell. Tandem perovskite solar cells (TPSCs) are a type of device...     

蒙皂石层间结构与性质关系的分子模拟研究进展

综述了计算机模拟中的分子力学、Monte Carlo和分子动力学模拟方法及其在蒙皂石层间结构中的应用进展,涉及粘土-水-离子体系的位能函数、粘土的水化和层间结构、热力学性质、物理机械性质和柱撑蒙脱石等各个方面.指出分子模拟对蒙皂石层间分子行为的基础研究将发挥重要作用.     

Investigation of convection and diffusion during biodiesel production in packed membrane reactor using 3D simulation

The 3D simulation of convection and diffusion phenomena within a ceramic membrane during transesterification reaction was the aim of this study. The ceramic membrane was a tubular micro porous TiO₂/Al₂O₃ packed with the heterogeneous catalyst. The Navier–Stokes, Brinkman and Stephan–Maxwell equations were applied for investigation of fluid flow reaction and mass transfer within the system. The value of the convection was generally between 10⁴ and 10⁷ times higher than diffusion. It depends on concentration component, the diffusion coefficient and components velocity. A good agreement was found with the maximum deviation of 8% from experimental data.     

3D Single Bubble Breakup Tracking in a Stirred Tank

A detailed understanding of turbulent fluid particle breakup mechanisms is essential for the accurate modeling of gas/liquid and liquid/liquid dispersions. The design of a fully automated setup for the three‐dimensional serial examination of the single bubble breakup process in a stirred tank, ensuring high repetition rates necessary for the additionally automated statistical analysis, is described. The implementation of a three‐dimensional automatic bubble breakup tracking tool is illustrated. At last, exemplary bubble breakup trajectories that show the benefits and limitations of the developed system and method are discussed.     

Investigation of the active thickness of solid oxide fuel cell electrodes using a 3D microstructure model

A 3D microstructure model is used to investigate the effect of the thickness of the solid oxide fuel cell (SOFC) electrode on its performance. The 3D microstructure model, which is based on 3D Monte Carlo packing of spherical particles of different types, can be used to handle different particle sizes and generate a heterogeneous network of the composite materials from which a range of microstructural properties can be calculated, including phase volume fraction, percolation and three phase boundary (TPB) length. The electrode model can also be used to perform transport and electrochemical modelling such that the performance of the synthetic electrode can be predicted. The dependence of the active electrode thickness, i.e. the region of the anode, which is electrochemically active, on operating over-potential, electrode composition and particle size is observed. Operating the electrode at an over-potential of above 200 mV results in a decrease in the active thickness with increasing over-potential. Reducing the particle size dramatically enhances the percolating TPB density and thus the performance of the electrode at smaller thicknesses; a smaller active thickness is found with electrodes made of smaller particles. Distributions of local current generation throughout the electrode reveal the heterogeneity of the 3D microstructure at the electrode/electrolyte interface and the dominant current generation in the vicinity of this interface. The active electrode thickness predicted using the model ranges from 5 μm to 15 μm, which corresponds well to many experimental observations, supporting the use of our 3D microstructure model for the investigation of SOFC electrode related phenomena.     

3D Investigation of 8-nm Tapered n-FinFET Model

The miniaturization has become a key word for advanced integrated circuits over the last few years. It is within this context that the fin field effect tra     

Improved Design of Shearing Sections with New Calculation Models Based on 3D Finite‐Element Simulations

New models for the Maddock and spiral shearing sections have been developed, employing three‐dimensional finite element analysis (3D FEA). These models describe the pressure‐throughput and power consumption behavior of the shearing sections for both the extrusion and the injection molding process and have been implemented in the REX 6.0 and PSI 4.0 simulation software. As a consequence it is now possible to describe the process behavior of these shearing sections within just a few seconds with the accuracy of FEA calculations.

Actual Maddock shearing section (left) and actual spiral shearing section (right).     

Investigation of Vitamin D2 and Vitamin D3 Hydroxylation by Kutzneria albida

The active vitamin D metabolites 25-OH−D and 1α,25-(OH)₂−D play an essential role in controlling several cellular processes in the human body and are potentially effective in the treatment of several diseases, such as autoimmune diseases, cardiovascular diseases and cancer. The microbial synthesis of vitamin D₂ (VD₂) and vitamin D₃ (VD₃) metabolites has emerged as a suitable alternative to established complex chemical syntheses. In this study, a novel strain, Kutzneria albida, with the ability to form 25-OH−D₂ and 25-OH−D₃ was identified. To further improve the conversion of the poorly soluble substrates, several solubilizers were tested. 100-fold higher product concentrations of 25-OH−D₃ and tenfold higher concentrations of 25-OH−D₂ after addition of 5 % (w/v) 2-hydroxypropyl β-cyclodextrin (2-HPβCD) were reached. Besides the single-hydroxylation products, the human double-hydroxylation products 1,25-(OH)₂−D₂ and 1,25-(OH)₂−D₃ and various other potential single- and double-hydroxylation products were detected. Thus, K. albida represents a promising strain for the biotechnological production of VD₂ and VD₃ metabolites.     

Design and Investigation of Split Gate Dielectric Modulated JLFET for Detection of Biological Molecule Using TCAD Simulation

Silicon - Here, a split gate insulator-controlled Junction less FET also known as SG-DM-JLFET is investigated and proposed to recognize biomolecules such as uricase, biotin, or aminopropyl-...     

立体编织预制体用自动单针插刺机设计

介绍了立体编织预制体成型工艺过程中,单针插刺工艺的自动化,提出了自动单针插刺机的总体设计方案,研究了方案的机构功能及工作过程。自动单针插刺机研制,可提高生产效率,优化成型工艺性能,适应立体编织预制体形状复杂化、大型化的趋势要求。     

Investigation of Single Event Transient Induced by Process Variability in 14 nm High-k/Metal Gate SOI FinFET Devices

Silicon - With the down scaling of device dimensions, FinFET structure faces the problem of the increasing process variability which results to the device performance mismatch. By technology...     

PDS中夹套管三维工程设计实践探讨

夹套管伴热是类似于套管换热器的一种管道伴热形式,因伴热效果均匀而广泛应用于石化、化工等领域。由于其结构的复杂性,夹套管在工厂设计系统(PDS)中的三维工程设计一直存在技术难点。采用一种新的方法,结合工程实例详细论述PDS中如何实现夹套管的三维工程设计。     

Color naming experiments using 2D and 3D rendered samples

This article describes a color naming experiment using 2D and 3D rendered color samples. Conventional color naming experiments using a priori clues generally involve 2D clues such as color patches. However, in real‐world scenes, most objects have 3D shapes whose colors are affected by illumination effects such as shadows and gloss. We use 2D and 3D rendered samples as clues in the experiments, and analyze the relationship between color terms and object surfaces. First, we develop a color term collection system that can produce 218 test colors. We render the color images of a flat disk as a 2D sample and a sphere as a 3D sample on a calibrated display device. It is supposed that the 2D and 3D surfaces with the same object color are obtained under the same conditions of viewing and illumination. The results of color naming experiments show that there are differences for color terms between 2D and 3D samples. Important findings are as follows: (1) brighter color terms tend to be chosen for the 3D samples than the 2D samples, when observing achromatic colors, (2) achromatic color terms are chosen for 3D samples having low saturation, and (3) for chromatic colors, a darker color term is generally chosen in comparison to the corresponding 2D samples of the same color. These properties become more prominent by changing the illumination angle from 0° to 45° to the surface normal. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 270–280, 2015     

复杂花纹子午线轮胎水滑特性仿真研究

基于LS-DYNA非线性有限元分析软件,建立具有复杂胎面花纹的175/65R14子午线轮胎三维有限元模型.通过轮胎径向刚度试验验证所建轮胎有限元模型的有效性,并在此基础上构造轮胎水滑仿真分析模型.使用ALE算法处理轮胎与水流间的流固耦合关系,仿真分析轮胎从静止到水滑现象产生的全过程,获得的轮胎临界水滑速度与经验公式的计算结果具有较好的一致性.3种不同花纹轮胎水滑速度仿真结果在趋势上与预期一致,进一步说明了有限元方法对轮胎水滑特性仿真评价的有效性.