可动态维护的软件体系结构

将软件维护的方法和技术划分为方法级、源代码级和目标代码级等３个层次,并给出了可在目标代码级支持软件动态维护的软件的体系结构。     

一种单片机应用系统中I／O接口配置及实现方法

从研制开发产品的角度,通过典型的实例,分析讨论单片机应用系统中Ｉ／Ｏ接口的配置及实现方法。     

贝克曼离心机故障排除两例

简要介绍贝克曼离心机触摸键盘失控和控制参数显示混乱两例故障的故障现象、故障分析以及故障排除方法。     

Error estimation in peak‐shape analysis of XPS core‐level spectra using UNIFIT 2003: how significant are the results of peak fits?

An error analysis for numerically evaluating random uncertainties in x‐ray photoelectron spectroscopy has been implemented in version 2003 of the spectra treatment and analysis software UNIFIT in order to improve the understanding of the statistical basis and the reliability of the model parameters for photoelectron spectra. The theoretical basis as well as two approaches to obtain error limits of the fit parameters have been considered. Several test spectra have been analysed and discussed. A representative example has been chosen to demonstrate the relevance of the error estimation for practical surface analysis. Suggestions for the minimization of errors in the peak‐fitting procedures are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

Optimization of a GFAAS method for determination of total inorganic arsenic in drinking water

The new 10 μg l⁻¹ arsenic standard in drinking water has been a spur to the search for reliable routine analytical methods with a limit of detection at the μg l⁻¹ level. These methods also need to be easy to handle due to the routine analyses that are required in drinking water monitoring. Graphite furnace atomic absorption spectrometry (GFAAS) meets these requirements, but the limit of detection is generally too high except for methods using a pre-concentration or separation step. The use of a high-intensity boosted discharge hollow-cathode lamp decreases the baseline noise level and therefore allows a lower limit of detection. The temperature program, chemical matrix modifier and thermal stabilizer additives were optimized for total inorganic arsenic determination with GFAAS, without preliminary treatment. The optimal furnace program was validated with a proprietary software. The limit of detection was 0.26 μg As l⁻¹ for a sample volume of 16 μl corresponding to 4.2 pg As. This attractive technique is rapid as 20 samples can be analysed per hour. This method was validated with arsenic reference solutions. Its applicability was verified with artificial and natural groundwaters. Recoveries from 91 to 105% with relative standard deviation <5% can be easily achieved. The effect of interfering anions and cations commonly found in groundwater was studied. Only phosphates and silicates (respectively at 4 and 20 mg l⁻¹) lead to significant interferences in the determination of total inorganic arsenic at 4 μg l⁻¹.     

The index of ideality of correlation: improvement of models for toxicity to algae

Toxicity to algae is important characteristic of substances from ecologic point of view. The CORAL software (http://www.insilico.eu/coral) gives possibility to build up model of toxicity to algae using data on the molecular architecture and experimental toxicity, without additional data on physicochemical and/or biochemical parameters. Considerable improvement of the model is observed in the case of using the index of ideality of correlation (IIC) in the role of additional criterion of predictive potential. The IIC is calculated with using of the correlation coefficient between experimental and calculated values of endpoint for the calibration set, with taking into account the positive and negative dispersions between experimental and calculated values. The best model calculated with use the IIC is characterized (the validation set) by n?=?50, r²?=?0.947, RMSE?=?0.401 whereas, model calculated without use the IIC is characterized by n?=?50, r²?=?0.805, and RMSE?=?0.539. The suggested models are built up in accordance to five OECD principles.

     

GROMACS: fast, flexible, and free

This article describes the software suite GROMACS (Groningen MAchine for Chemical Simulation) that was developed at the University of Groningen, The Netherlands, in the early 1990s. The software, written in ANSI C, originates from a parallel hardware project, and is well suited for parallelization on processor clusters. By careful optimization of neighbor searching and of inner loop performance, GROMACS is a very fast program for molecular dynamics simulation. It does not have a force field of its own, but is compatible with GROMOS, OPLS, AMBER, and ENCAD force fields. In addition, it can handle polarizable shell models and flexible constraints. The program is versatile, as force routines can be added by the user, tabulated functions can be specified, and analyses can be easily customized. Nonequilibrium dynamics and free energy determinations are incorporated. Interfaces with popular quantum-chemical packages (MOPAC, GAMES-UK, GAUSSIAN) are provided to perform mixed MM/QM simulations. The package includes about 100 utility and analysis programs. GROMACS is in the public domain and distributed (with source code and documentation) under the GNU General Public License. It is maintained by a group of developers from the Universities of Groningen, Uppsala, and Stockholm, and the Max Planck Institute for Polymer Research in Mainz. Its Web site is http://www.gromacs.org.     

Effects of glucose,glutamine, and malate on the metabolism of spodoptera frugiperda clone 9 (sf9) cells

Optimal design and operation of bioreactors for insect cell culture is facilitated by functional relations providing quantitative information on cellular metabolite consumption kinetics, as well as on the specific cell growth rates (μ_G). Initial specific consumption rates of glucose, malate, and oxygen, and associated changes in μ_G, were measured forSpodoptera frugiperda clone 9 (Sf9) cells grown in batch suspension culture in medium containing 7–35 mM glucose, 0–16 mM malate, and 4–16 mM glutamine. The initial specific glucose consumption rate (q _G ) could be described by a modified Michaelis-Menten equation treating malate as a “competitive” inhibitorK ₁ = 6.5 mM) and glutamine as a “noncompetitive” inhibitorK _I = 14 mM) ofq _G , with aK _m of 7.1 mM for glucose. All three carbon sources were found to increase μ_G in a saturable manner, and a modified Monod equation was employed to describe this relationship (μ_Gmax = 0.047 h^-1). The initial specific oxygen consumption rate (q_O2) in Sf9 cells could be related to μ_G by the maintenance energy model, and it was calculated that, under typical culture conditions, about 15–20% of the cellular energy demand comes from functions not related to growth. Fitted parameters in mathematical expression for μg: K₄, Monod constant for glucose (mM); K₅, modified Monod constant for malate (mM); K₆, Monod constant for glutamine (mM); m_o2, specific consumption rate of oxygen by the cells under zero-growth conditions (nmol/cell/h); q_F, initial specific fumarate production rate (nmol/cell/ h);q _G , initial specific glucose consumption rate (nmol/cell/h); q_Gmax, maximum initial specific glucose consumption rate (nmol/cell/h);q _M , initial specific malate consumption rate (nmol/cell/h); q_o2, initial specific oxygen consumption rate (nmol/cell/h); Y_o2, cell yield on oxygen (cells/nmol); μ, initial specific cell growth rate (h^-1); μ_g, initial specific cell growth rate (h^-1); μG_max, maximum initial specific cell growth rate (h^-1).