Comparison of various optimization approaches for fed-batch ethanol production

Various optimization techniques have been proposed to optimize the feedrate profile to maximize ethanol production. Among them are the differential algebraic system (DAS) approach, Kelly transformation approach, singular control approach, and on-off control approach. These methods are compared and it is shown that the DAS approach and Kelly transformation method are equivalent. A nonsingular transformation approach is presented. The performance obtained with the nonsingular approach is the same as that obtained with the singular approach and better than those obtained with the DAS and on-off control approaches.     

前、后路手术治疗颈脊髓损伤的效果比较

目的比较前、后路手术治疗颈脊髓损伤的临床效果。方法选取78例颈脊髓损伤患者,抽签随机分为两组,其中39例采用前路手术治疗患者记为前路术组,另外39例采用后路手术治疗记为后路术组,观察两组手术相关指标并结合术后有效随访比较治疗综合效果。结果前路术组手术时间(75.4±10.2)min、术中出血量(206.3±31.5)m L较后路术组明显较低,术后1年颈椎功能JOA评分(14.4±1.8)分较后路术组显著较高(P0.05);前路术组不良结果发生率5.13%较后路术组低(P0.05)。结论同后路手术相比,前路手术具有手术时间短、术中出血量少的特点,且能有效减少术后不良结果的发生,对病情康复和改善预后具有重要意义。     

量子Monte Carlo处理激发态

提出了用于电子激发态的剩余函数变分量子ＭｏｎｔｅＣａｒｌｏ（ＳＦＶＭＣ）方法,已经证明：若激发态的初始波函数与基态的初始波函数属于对称性不同的不可约表示时,该激发态的ＳＦＶＭＣ方法与基态的ＳＦＶＭＣ方法完全相同;若激发态的初始波函数与基态的初始波函数有相同的对称性时,只要对激发态的初始波函数作正交性修正,则其态的ＳＦＶＭＣ方法亦可推到该激发态的情况。文章导出了这第二类激发态的ＳＦＶＭＣ方法的详细计     

A dual-level approach to density-functional theory

An efficient approximate scheme for density-functional theory (DFT) calculations, which eliminates the time-consuming self-consistent-field (SCF) procedure, is proposed using a dual-level DFT approach. In this approach, dual levels of basis sets and exchange-correlation functionals are adopted. The dual-level DFT approach is based on the idea that the total electron density in the ground state can be represented in terms of the density evaluated using the low-quality basis set and the low-cost exchange-correlation functional. Since the SCF procedure is avoided in the total energy evaluation, the dual-level DFT approach drastically reduces the computational cost. The applications of several dual-level DFT calculations to molecular systems show that our approach is more efficient than the self-consistent DFT approach with a moderate accuracy.     

挥发诱导自组装法制备结构有序的有机-无机纳米复合材料*

挥发诱导自组装方法（EISA）可以用来模拟自然界中的有机-无机杂化材料的纳米有序结构的形成过程。这是一种新兴的、有效的合成结构有序纳米复合材料的方法,其具有快速、简便、高效的特点。本文就挥发诱导自组装方法的原理及利用该方法制备结构有序的有机-无机纳米复合材料(MSC材料)的机理、有关影响MSC材料有序结构形成的因素作了详细探讨,并对利用EISA方法制备MSC材料的研究和发展前景进行了展望。     

Critical thoughts on computing atom condensed Fukui functions

Different procedures to obtain atom condensed Fukui functions are described. It is shown how the resulting values may differ depending on the exact approach to atom condensed Fukui functions. The condensed Fukui function can be computed using either the fragment of molecular response approach or the response of molecular fragment approach. The two approaches are nonequivalent; only the latter approach corresponds in general with a population difference expression. The Mulliken approach does not depend on the approach taken but has some computational drawbacks. The different resulting expressions are tested for a wide set of molecules. In practice one must make seemingly arbitrary choices about how to compute condensed Fukui functions, which suggests questioning the role of these indicators in conceptual density-functional theory.     

Density functional theory: Approximating quasiparticle density functional

A constructive approach for deriving the approximating quasiparticle energy density functional is proposed. As a matter of fact, the proposed approach is the direct development of the Kohn–Sham quasiparticle concept and the Levy–Valone approach. The approach presented takes into account a pseudopotential character of the exchange-correlation part of the density functional and results in a system of functional equations to obtain ground-state energies of many-electron systems.     

Evaluation of uncertainty utilising the component by component approach

 This paper reviews the so-called "component by component approach" of evaluating measurement uncertainty. An overview of the evaluation process is given followed by an in-depth discussion of some of the differences between this approach and the approach of utilising validation data. Some of the advantages and disadvantages of using the component by component approach are outlined at the end. Received: 4 August 1999 · Accepted: 11 November 1999     

中空结构聚合物微粒的制备方法

对国内外有关中空结构聚合物微粒(包括微球和乳液粒子)的制备方法进行了综述，包括自组装法，模板法以及乳液法等。参考了国内外最新的40余篇论文和专利文献。     

Combined plane wave and localized orbital electronic structure calculation: Adsorption energy of hydrogen on Pd(111)

To achieve the necessary accuracy when calculating the electronic structures of materials, for example, for surface or bulk models, we propose a combined plane wave (PW) and localized orbital (LO) electronic structure calculation approach. A high level theory calculation based on the LO approach can be used to describe chemical reactions and other electronic processes using a cluster model. Conversely, the electronic structure of a surface or bulk model is best calculated using a PW approach. In this study, we analyzed the potential energy surface of a hydrogen atom adsorption on a Pd(111) surface using our proposed combined PW and LO approach. We clearly demonstrate that the combined PW and LO approach is both effective and necessary to determine local surface phenomena. We expect that the proposed approach will be effective for a broad range of applications in the material science field.     

Real-time monitoring of biomolecular interactions in blood plasma using a surface plasmon resonance biosensor

We report a novel approach to biosensor-based observations of biomolecular interactions which enables real-time monitoring of biomolecular interactions in complex media. This approach is demonstrated by investigating the interaction between the human chorionic gonadotropin (hCG) and its antibody in blood plasma using a surface plasmon resonance biosensor and a dispersionless microfluidics system. The real-time binding data obtained in blood plasma are compared with those obtained in buffer and blood plasma using a conventional method. It is also demonstrated that the proposed approach can enhance the capability of the biosensor to detect biomolecules in complex samples in terms of detection time and sensitivity. In the model experiment, this approach is shown to enable direct detection of hCG in blood plasma at levels which are five times lower than those detected using the conventional detection approach.     

Frontier orbitals aromaticity: A simple approach to the analysis of pericyclic reactions

A new and simple approach to the analysis of pericyclic reactions based on combination of the interaction of HOMO-LUMO molecular orbitals and Huckel-Mobius aromaticity concept in transition state is reported. This approach seems to be more powerful than the Woodward-Hoffmann approach which appears to be limited to reactions with sufficiently high symmetry, and the Huckel-Mobius that use the non-participating lowest basis set (Ψ₁). One important impact of the current approach is its capability in addressing the photochemical concerted reactions.     

荧光量子点的水相合成及其在化学和生物分析中的应用

荧光量子点(又称为半导体纳米晶体)是一种新兴的无机发光材料, 由于其具有独特的结构和光电性能, 在发光二极管、太阳能电池及生命科学等领域有广泛的应用. 目前, 有机相合成法和水相合成法已被成功地用于荧光量子点的合成. 与有机相合成法相比, 水相合成量子点方法简单、绿色且廉价, 合成的量子点水溶性好, 在生物医学等领域具有很好的应用前景. 本文主要介绍荧光量子点的水相合成方法及其在化学和生物分析中的应用, 并对其发展趋势进行了展望.     

Investigating Localized Electrochemical of Ferrocenyl-Imidazolium in Ionic Liquid Using Scanning Electrochemical Microscopy Configuration

In the present work, the localized electrochemical behavior of redox molecule in ionic liquid has been investigated using scanning electrochemical microscopy. The electrochemical response of ferrocenyl-imidazolium redox mediator was studied by recording approach curves over a conducting and insulating substrate in an undiluted ionic liquid. The SECM approach curve over the conducting substrate displays a positive feedback, as observed in classical solvent. However, in the case of the insulating substrate, the approach curve reveals different shapes, depending on the used approach speed. In this configuration, low approach speed is necessary to reach the expected negative feedback. Interestingly, at a very close distance between the UME and the insulating substrate, a thin film behavior is revealed. In addition, the approach curves on both insulator and conducting substrates can be reconstructed from punctual responses at different distance tip-substrate. The latter match perfectly with the expected theoretical curves over conducting and insulating under diffusion control.     

Modeling adhesion forces between deformable bodies by FEM and Hamaker summation

A new numerical approach is presented for predicting adhesion forces of particles at flat and rough surfaces. The new hybrid method uses the finite element method (FEM) for the determination of elastic and plastic particle deformation combined with numerical Hamaker summation. In the numerical approach, the influence of the plastic deformation can be fully included. We show how the adhesion force depends on the contact geometry and the material properties. For easy comparison with other models, the force-displacement behavior of the systems is presented. The numerical approach is supported by atomic force microscopy (AFM) measurements. The experimentally observed adhesion force hysteresis is described very well by the new approach. Although calculations in this article are focused on spherical particles, our approach can be extended to particles of arbitrary shapes.     

Colloidal aspects of eating

This paper is an overview of the work currently carried out on the microstructural approach to reduce unhealthy ingredients in everyday foods, while maintaining the positive eating aspects of the original product. Fat reduction is discussed in detail as an example of how the approach might be used. In particular, we will cover the very new approach using tribology based physical measurements and relate this to oral response as opposed to using rheological measurements. Materials such as low fat, air/oil-in-water and water-in-water emulsions as well as sheared (or fluid) gels will be discussed as this approach has allowed physical, chemical and sensory properties of high fat content foods to be matched by structures containing considerably less fat. This microstructural approach to the engineering challenge of fat replacement has proved very successful in the development of mayonnaise, cream and sauces with good eating properties. If the approach discussed continues to be developed, they promise significant advancement and rewards on the formulation of healthy everyday foods which are perceived by the consumer as indulgent.     

Geometric constraints in semiclassical initial value representation calculations in Cartesian coordinates: accurate reduction in zero-point energy

An approach for the inclusion of geometric constraints in semiclassical initial value representation calculations is introduced. An important aspect of the approach is that Cartesian coordinates are used throughout. We devised an algorithm for the constrained sampling of initial conditions through the use of multivariate Gaussian distribution based on a projected Hessian. We also propose an approach for the constrained evaluation of the so-called Herman-Kluk prefactor in its exact log-derivative form. Sample calculations are performed for free and constrained rare-gas trimers. The results show that the proposed approach provides an accurate evaluation of the reduction in zero-point energy. Exact basis set calculations are used to assess the accuracy of the semiclassical results. Since Cartesian coordinates are used, the approach is general and applicable to a variety of molecular and atomic systems.     

Improving the accuracy of density-functional theory calculation: the genetic algorithm and neural network approach

The combination of genetic algorithm and neural network approach (GANN) has been developed to improve the calculation accuracy of density functional theory. As a demonstration, this combined quantum mechanical calculation and GANN correction approach has been applied to evaluate the optical absorption energies of 150 organic molecules. The neural network approach reduces the root-mean-square (rms) deviation of the calculated absorption energies of 150 organic molecules from 0.47 to 0.22 eV for the TDDFTB3LYP6-31G(d) calculation, and the newly developed GANN correction approach reduces the rms deviation to 0.16 eV.     

A toxicity evaluation and predictive system based on neural networks and wavelets

A computational approach has been developed for performing efficient and reasonably accurate toxicity evaluation and prediction. The approach is based on computational neural networks linked to modern computational chemistry and wavelet methods. In this paper, we present details of this approach and results demonstrating its accuracy and flexibility for predicting diverse biological endpoints including metabolic processes, mode of action, and hepato- and neurotoxicity. The approach also can be used for automatic processing of microarray data to predict modes of action.