一种基于有限元网格的车身CAD曲面数据修复方法

针对车身CAD中非同构数据格式间的转换使自由形体的近似值发生变化而导致曲面片之间产生缝隙或网格叠加的情况，提出了一种基于有限元网格、应用于车身CAD曲面网格数据自动修复的方法。该方法还能够在一定程度上局部修复原来划分有缺陷的网格，从而降低对车身CAD模型有限元网格划分的质量要求，并通过工业复杂成形件的实际处理结果验证了该方法的有效性。     

TiberCAD: A new multiscale simulator for electronic and optoelectronic devices

In the last years GaN-based heterostructures have attracted much attention for their application as optoelectronic devices. The strain due to lattice mismatch of the constituent materials plays a crucial role in the behaviour of these structures, especially if they are of reduced dimensions, as e.g. nanocolumns. We show an implementation of a new device simulator which accounts for strain-related effects and quantum mechanical properties and couples them with the transport of the quasi-particles in the system. Simulations of an AlGaN/GaN nanocolumn LED are reported as an example.     

CFD‐based multi‐objective optimization method for ship design

This paper concerns development and demonstration of a computational fluid dynamics (CFD)‐based multi‐objective optimization method for ship design. Three main components of the method, i.e. computer‐aided design (CAD), CFD, and optimizer modules are functionally independent and replaceable. The CAD used in the present study is NAPA system, which is one of the leading CAD systems in ship design. The CFD method is FLOWPACK version 2004d, a Reynolds‐averaged Navier–Stokes (RaNS) solver developed by the present authors. The CFD method is implemented into a self‐propulsion simulator, where the RaNS solver is coupled with a propeller‐performance program. In addition, a maneuvering simulation model is developed and applied to predict ship maneuverability performance. Two nonlinear optimization algorithms are used in the present study, i.e. the successive quadratic programming and the multi‐objective genetic algorithm, while the former is mainly used to verify the results from the latter. For demonstration of the present method, a multi‐objective optimization problem is formulated where ship propulsion and maneuverability performances are considered. That is, the aim is to simultaneously minimize opposite hydrodynamic performances in design tradeoff. In the following, an overview of the present method is given, and results are presented and discussed for tanker stern optimization problem including detailed verification work on the present numerical schemes. Copyright © 2006 John Wiley & Sons, Ltd.     

A Network Computing Environment for TWT-CAD

Based on RPC semantic and agent-oriented software bus, a task-level-parallel Distributed-Object-Computing model has been designed to have complicated numerical analysis and Visualization in Scientific Computing(ViSC) for TWT-CAD, while making use of object-oriented technology and thread-concurrence technology. The ViSC software running on a Windows NT LAN(Local Area Network) for beam-wave interaction of TWTs has been developed in Visual C++, of which software architecture and key technologies are given in the paper.     

Shape recovery for sparse‐data tomography

A two‐dimensional sparse‐data tomographic problem is studied. The target is assumed to be a homogeneous object bounded by a smooth curve. A nonuniform rational basis splines (NURBS) curve is used as a computational representation of the boundary. This approach conveniently provides the result in a format readily compatible with computer‐aided design software. However, the linear tomography task becomes a nonlinear inverse problem because of the NURBS‐based parameterization. Therefore, Bayesian inversion with Markov chain Monte Carlo sampling is used for calculating an estimate of the NURBS control points. The reconstruction method is tested with both simulated data and measured X‐ray projection data. The proposed method recovers the shape and the attenuation coefficient significantly better than the baseline algorithm (optimally thresholded total variation regularization), but at the cost of heavier computation.     

Determination of lipid content and stability in lipid nanoparticles using ultra high-performance liquid chromatography in combination with a Corona Charged Aerosol Detector

For many years, lipid nanoparticles (LNPs) have been used as delivery vehicles for various payloads (especially various oligonucleotides and mRNA), finding numerous applications in drug and vaccine development. LNP stability and bilayer fluidity are determined by the identities and the amounts of the various lipids employed in the formulation and LNP efficacy is determined in large part by the lipid composition which usually contains a cationic lipid, a PEG-lipid conjugate, cholesterol, and a zwitterionic helper phospholipid. Analytical methods developed for LNP characterization must be able to determine not only the identity and content of each individual lipid component (i.e., the parent lipids), but also the associated impurities and degradants. In this work, we describe an efficient and sensitive reversed-phase chromatographic method with charged aerosol detection (CAD) suitable for this purpose. Sample preparation diluent and mobile phase pH conditions are critical and have been optimized for the lipids of interest. This method was validated for its linearity, accuracy, precision, and specificity for lipid analysis to support process and formulation development for new drugs and vaccines.     

Fair cubic transition between two circles with one circle inside or tangent to the other

This paper describes a method for joining two circles with a C-shaped and an S-shaped transition curve, composed of a cubic Bézier segment. As an extension of our previous work; we show that a single cubic curve can be used for blending or for a transition curve preserving G ² continuity regardless of the distance of their centers and magnitudes of the radii which is an advantage. Our method with shape parameter provides freedom to modify the shape in a stable manner.     

样条函数在光学器件设计和优化中的建模与应用

讨论了样条函数在光学器件设计和优化过程中的建模方法与应用。提出了用样条函数进行太阳能会聚器的优化设计。根据太阳能会聚器曲面的设计要求,首先讨论了抛物面与高次非球曲面的光学性能,然后给出了样条函数的数学模型和优化设计过程。基于光学设计软件CODE V的计算机仿真结果表明,它与通常的抛物面会聚器相比,样条函数方法具有太阳能转换效率高、系统可实现间断跟踪太阳和成本低等优点。     

机械设计在CAD中图表资料的处理

机械设计中，有许多复杂的数据信息需要处理，本文主要探讨了齿轮传动中有关数据，表格和线圈的程序化处理方法。     

Comparison of two aerosol-based detectors for the analysis of gabapentin in pharmaceutical formulations by hydrophilic interaction chromatography

Comparison of hydrophilic interaction chromatography (HILIC) columns coupled with an evaporative light scattering detector (ELSD) or charged aerosol detector (CAD) was done for the detection of gabapentin in pharmaceutical formulations. The chromatographic separations were achieved on four HILIC columns: ZIC HILIC, ZIC pHILIC, Luna HILIC, and Atlantis HILIC. Experimental factors such as mobile phase composition, acetonitrile content, and mobile phase pH were evaluated. Validation of method was done in terms of linearity, sensitivity, accuracy, and precision. The performance of ELSD detection method is comparable to that of CAD. The intra-day and inter-day variations were below 1.7% and 3.2% for CAD and 2.8%, and 3.4% for ELSD, respectively. In addition, detection sensitivities of ELSD, CAD, and UV detectors were also compared for HILIC and reversed phase (RP) modes and the highest sensitivities were obtained in the HILIC mode when connected with CAD and ELSD. The developed HILIC aerosol based detection methods were successfully applied to the analysis of gabapentin in commercial tablets and capsules.