熔体塔式造粒法生产尿基复混肥

化肥企业生产尿基复混肥对于农业科学施肥、提高肥料利用率、避免环境污染及促进企业产品结构调整都具有十分重要的意义。熔体塔式造粒法生产尿基复混肥较之其它方法优越性更为显著,笔者简要介绍该法的生产机理、工艺流程、技术特点、国内现状及产品市场前景等方面的一些情况。     

优选法在选择刀具角度中的运用

应用优选法确定刀具几何参数,优选得γ=20°,主偏角φ=81°,刃倾角λ=20°,使生产率提高3倍。     

玻璃纤维毡增强热塑性复合片材的研制和应用

本文简要介绍了玻璃纤维毡增强聚丙烯片材的研制，性能和应用。     

Development of the meshless finite volume particle method with exact and efficient calculation of interparticle area

The Finite Volume Particle Method (FVPM) is a meshless method based on a definition of interparticle area which is closely analogous to cell face area in the classical finite volume method. In previous work, the interparticle area has been computed by numerical integration, which is a source of error and is extremely expensive. We show that if the particle weight or kernel function is defined as a discontinuous top-hat function, the particle interaction vectors may be evaluated exactly and efficiently. The new formulation reduces overall computational time by a factor between 6.4 and 8.2. In numerical experiments on a viscous flow with an analytical solution, the method converges under all conditions. Significantly, in contrast with standard FVPM and SPH, error depends on particle size but not on particle overlap (as long as the computational domain is completely covered by particles). The new method is shown to be superior to standard FVPM for shock tube flow and inviscid steady transonic flow. In benchmarking on a viscous multiphase flow application, FVPM with exact interparticle area is shown to be competitive with a mesh-based volume-of-fluid solver in terms of computational time required to resolve the structure of an interface.     

A conservative discontinuous Galerkin scheme for the 2D incompressible Navier–Stokes equations

In this paper we consider a conservative discretization of the two-dimensional incompressible Navier–Stokes equations. We propose an extension of Arakawa’s classical finite difference scheme for fluid flow in the vorticity–stream function formulation to a high order discontinuous Galerkin approximation. In addition, we show numerical simulations that demonstrate the accuracy of the scheme and verify the conservation properties, which are essential for long time integration. Furthermore, we discuss the massively parallel implementation on graphic processing units.     

一步法生产涤纶FDY工艺的探讨

利用ＫＶ７３１纺丝设备一步法生产出涤纶ＦＤＹ，探讨了热辊拉伸和熔体温度对纤维质量的影响。采用高特性粘数的聚酯切片，严格控制纺丝工艺，可以在５０００ｍ／ｍｉｎ的纺丝速度下纺制高质量的细旦涤纶ＦＤＹ。     

Proposal of a uniform color scale for virgin olive oils

A new color scale was developed from a broad data set of 1700 virgin olive oil samples over four crop seasons, which can be considered highly representative of the whole color range of virgin olive oils available in Spain. This color scale provides a new set of 60 color standards, improving the results achieved by the old 60-color standards proposed by the bromthymol blue method. Seeking the greatest possibility of including a near match between colors of virgin olive oils and proposed standards, we developed our new color scale using a recent uniform color space, with standards placed in a regular rhombohedral lattice like the one employed by the Uniform Color Scales of the Optical Society of America. The average color difference between each of the 1700 virgin olive oils and its nearest standard is reduced from 8.17 CIELAB units, using the bromthymol blue standards, to 3.99 CIELAB units using the new standards. Within a color tolerance of 7.0 CIELAB units, 93.2% of our virgin olive oils can be classified with the new standards, but only 59.1% with the bromthymol blue ones. In the interest of future adoption, the performance of the new color standards should be tested by industry and researchers.     

降维方法监督分类的比较研究

对ISOMap、LDA、LLE、PCA这4种典型降维算法的主要思想和算法步骤进行了详细分析,并将它们用于有监督分类。从实验结果分析得到结论 ,其可为有监督分类提供有益的借鉴。     

酚醛胺(T-31)环氧树脂固化剂之浅谈

介绍了酚醛胺(T-31)系列环氧固化剂及原料的现状和特点,并对酚醛胺(T-31)系列环氧固化剂进行了分代,阐述了第三代酚醛胺(T-31)系列环氧固化剂的系列化、专用化、高档化。预测和展望了2005年的需求和方向。