塑料光学零件的型芯材料

本文是作者在实践中的研究成果与总结。介绍了透明塑料光学透镜、棱镜注塑模具型芯常用材料应具备的基本特性及选取原则。同时还介绍了实践中碰到的一些具体问题,期望与同行共同探讨。     

A STOICHIOMETRIC DISPLACEMENT MODEL FOR RETENTION OF SOLUTE IN LIQUID CHROMATOGRAPHY WITH MULTI-COMPONENT SYSTEM

Considering all the kinds of interactions between solute and solvent, solute and stationary phase, solvent and stationary phase molecules as well as the competitional adsorption among various kinds of solvent molecules on the stationary phase, we present a stoichiometric displacement model of solute retention with four sets of parameters in liquid chromatography. This model was tested with data from both literature and experiments done by ourselves. These results show that this model may fit the experimental data for a liquid chromatography system with various kinds of mobile phases consisting of a complete range of multi-components and with different types of stationary phases.     

Unusual multi-component condensation in the synthesis of 1,4-dihydro-1,6-naphthyridine derivatives

Multi-component condensation of cyanoselenoacetamide with ethyl 2-furfuryl-idenacetoacetate and liquid alkyl halides, catalyzed byN-methylmorpholine, affords 7-alkylseleno-5-amino-8-cyano-3-ethoxycarbonyl-4-(2-furyl)-2-methyl-1,4-dihydro-1,6-naphthyridines, which have not been described hitherto. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 121–124, January, 2000.     

纳米银焊膏烧结大功率LED模块的高温可靠性研究

介绍了一种加速老化试验模型对LED模块进行寿命预测。分别采用纳米银焊膏、锡银铜焊料、导电银胶作为芯片粘结材料。控制环境温度和正向电流,在特定的时间测量光输出。比较了不同粘接材料及环境温度对LED老化过程的影响,并针对老化过程进行分析推导,建立老化数学模型,对其进行寿命预测。试验结果表明,纳米银焊膏粘接的模块对温度的抗性最好,纳米银焊膏有潜力在未来固态照明、投影和其他高功率器件领域得到应用。     

Partial nearest neighbor PDF for multi-component material systems

We develop general expressions for partial nearest neighbor probability density functions (PNNPDF’s) for equilibrium multi-component systems, valid for arbitrary partial densities, temperatures, and interaction potentials; thus providing an alternative means of describing structure at the microscopic (atomic scale) level for multi-component material systems. This paper thus complements an earlier paper (U.F. Edgal and D.L. Huber, J. Phys. Chem. B 108, 13777–13788 2004) in the analytical investigation of the classical statistical thermodynamics of multi-component systems. The connection between PNNPDF’s and the commonly employed partial m-body distribution functions is detailed. Results for PNNPDF’s and partial m-body distribution functions applicable for the poisson-distributed multi-component system and the low density binary mixture of hard spheres are provided. The statistical geometry of the systems is further studied through a brief investigation of particle clustering. A major hallmark of the above investigation involves the several multiple integrals and multiple sums encountered, that were quite formidable to perform, even in the absence of particle interactions.     

Microwave-assisted multi-component synthesis of fused 3-aminoimidazoles

A variety of fused 3-aminoimidazoles have been synthesised by a microwave assisted Ugi three-component coupling (3cc) reaction catalysed by scandium triflate in methanol as solvent. Yields of 33-93% have been achieved after just 10 min of microwave irradiation using a simple one-stage procedure. The methodology described is suitable for the rapid and efficient synthesis of a range of fused heterocycles of pharmacological interest.     

Use of Concentration Pulse Chromatography for Determining Binary Isotherms: Comparison with Statically Determined Binary Isotherms

The characterization of adsorption properties of binary gas mixtures is an important factor in the design of cyclic periodic adsorption processes. Presently, there are a few methods for determining the binary adsorption behaviour. However, most of these methods are very time demanding (static approaches). One dynamic approach for determining the binary adsorption behaviour is by employing the concentration pulse method. Although this experimental method has been shown to reliably reproduce the data obtained with static approaches, the application has been limited to systems where the adsorption capacities are similar. In our previous work, a novel method (HT-CPM) was shown to be capable of handling systems where the adsorption capacity of the heavy component is much greater than the light component.In order to further validate the novel method, HT-CPM, previously published statically determined binary adsorption data have been used to supply the data required for the concentration pulse method (CPM) data reduction techniques. From this data, the HT-CPM was then applied and the resulting data compared. The two other CPM approaches were also applied and these results are shown.Four binary systems were chosen so that a range of heavy/light adsorption capacities was examined. The results show that the HT-CPM was able to produce results that were consistent with the static data taken from the literature. The other data reduction techniques used with the CPM could only produce meaningful data when the adsorption capacities of the heavy and light components were similar.     

Lanthanide(III)-catalyzed multi-component aza-Diels-Alder reaction of aliphatic N-arylaldimines with cyclopentadiene

The Ln(OTf)₃-catalyzed formal aza-Diels-Alder (or Povarov) reaction of cyclopentadiene with in situ generated N-arylimines containing enolizable protons is described. This three-component Povarov reaction generates highly functionalized C-2 aliphatic substituted tetrahydroquinolines, heterocycles that were previously inaccessible using the Povarov reaction, because of the instability of the intermediate aliphatic N-arylaldimine.     

Effect of glass transition temperature of polymeric binders on properties ceramic materials

In the paper are presented the studies of the effect of glass transition temperature of new water-thinnable polymeric binders on the properties of ceramic materials obtained by die pressing. The parameters of ceramic samples comprising polymeric binders have been compared with those of samples comprising poly(vinyl alcohol) (PVA) — water-soluble binder. When using poly(acrylic-styrene) (AS), poly(acrylic-allyl) (AA) and poly(vinyl-allyl) (VA) water-thinnable binders, materials of greater density and mechanical strength were obtained in the green state as well as after sintering than those in the case of using PVA. The dependence of the chemical structure of the binders applied on the properties of samples such as the glass transition temperature and hydrophobic-hydrophilic balance of the copolymers has been discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

GPU Parallelization Computation of High-Dimensional Multi-Phase Separation in Complex Domains Based on the Corrected FPM北大核心CSCD

Based on the corrected finite pointset method (CFPM) with CPU-GPU heteroid parallelization (CFPM-GPU), a high-efficiency, accurate and fast parallel algorithm was developed for the high-dimensional phase separation phenomena governed by the multi-component Cahn-Hilliard (C-H) equation in complex domains. The proposed parallel algorithm with the CFPM-GPU was built in a process like: ① introduce the Wendland weight function into the discretization of the finite pointset method (FPM) scheme for the 1st/2nd spatial derivatives, based on the Taylor series and the weighted least square concept; ② use the above FPM scheme twice to approximate the 4th spatial derivative in the C-H equation, which is called the CFPM method; ③ for the first time establish an accelerating parallel algorithm for the CFPM with local matrices by means of a single GPU card based on the CUDA programming. Two benchmark problems of 2D radially and 3D spherically symmetric C-H equations were first solved to test the accuracy and high-efficiency of the proposed CFPM-GPU, and the acceleration ratio of the GPU parallelization to the single CPU computation is about 160. Subsequently, the proposed CFPM-GPU was used to predict the 2D/3D multi-phase separation phenomena in complex domains, and the prediction was compared with other numerical results. The numerical results show that, the proposed CFPM-GPU is valid and high-efficiency to simulate the 2D/3D multi-phase separation cases in complex domains. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.