低功耗便携式温度自动记录仪的设计

综合应用计算机技术、通信技术、数理统计和控制论的有关知识设计了能自动检测并记忆温度的仪器,该仪器具有掉电自动保护、低功耗、便携的特点,并具有智能性,能预测温度变化趋势,有超前警示和及时报警两种报警功能。     

Clusters in a mixture of an "amphiphilic" ionic liquid and a nonionic liquid: theoretical study

A Flory-Huggins type lattice approach is used to describe theoretically a heterogeneous mixture composed of an ionic liquid (IL) and a nonionic liquid (nIL). It is analyzed, how the behavior of the system depends on the difference in the affinities of the cations and the anions to the neutral molecules (i.e., on the "amphiphilicity" of the IL with respect to the nIL). It is proved that if the difference in the affinities is not large, two macrophases coexist in the mixture; if the difference exceeds a certain threshold value, the mixture becomes microheterogeneous: depending on its composition, it can turn either into ion clusters dispersed over the phase having low concentration of ions, or into clusters of neutral molecules dispersed over the phase having high concentration of ions. If the system is not close to the critical point, the ion clusters can be only small: the maximal ratio of their diameter to an ion diameter is of the order of ten; however, the clusters of nonionic molecules can be large, if the difference in the affinities has a certain value. It is predicted also that cavities can nucleate inside an IL, and clusters of ions can appear in a saturated vapor of an IL.     

A modular photocurrent generation system based on phospholipid-assembled fullerenes

A modular photoconversion system based on phospholipid-incorporated fullerene is reported. It relies on the noncovalent formation of a lipid bilayer on an electrode to achieve precise placement of fullerene and can be quickly implemented in aqueous media. Photosensitizing dyes can be conveniently added to the system to achieve higher conversion efficiency. It is suggested that amphiphilic lipids are attractive materials for organic solar cells because of their versatility in molecular assembly and chemical conjugation.     

A comprehensive approach to argumentation

A reasoning model, based on the logic of argumentation, is described. The model represents argumentation as a directed graph in which nodes and arcs can be colored using an ordinal set of weightings and in which the attributes of both nodes and arcs can be modified. It is thus able to deal with the undercutting or augmenting of arguments. Weightings can be propagated through the graph to generate unique weightings for any node or arc. The model is able to deal with contradiction. It can incorporate numerical methods and is able to handle qualitative and quantitative reasoning.     

凝聚相有机磷酸酯红外光谱解析研究中计算机的应用

为了更方便有效地进行凝聚相有机磷酸酯的红外光谱规律及谱图解析的研究,利用计算机的软、硬件技术设计出一套用于微机的光谱辅助分析软件包,功能齐全,操作灵活,可完成多种化合物分类模式检索;可进行多谱图叠加,吸收峰直方图的显示,峰的自动识别及范围确定;可进行差谱分析;谱图显示操作灵活,可进行绘图仪输出。在实际分析应用中有较好的效果。     

Fluorescence quenching by reversible excimer formation: Kinetics and yield predictions for a classical potential association-dissociation model

Fluorescence quenching by reversible excimer formation is studied on the assumption that excimer formation and dissociation can be modelled as entering and leaving the attractive region of an monomer excited-monomer interaction potential by diffusion. To get some general insight in the kinetic consequences of such a type of modelling, the simple case of an attractive square-well potential is investigated. It is shown that three different kinetic regimes have to be distinguished: Two "reversible" ones in case of slow excimer radiative decay, in which the quenching kinetics can be formulated by Markovian or non-Markovian rate equations with both excimer formation and excimer dissociation terms, and an effectively "irreversible" regime if the excimer radiative decay is too rapid to allow the excimer equilibration. In the latter case a dissociation coefficient can no longer be defined and the quenching kinetics can only be predicted on the basis of generalized rate equations of a net-excimer-formation type. It is shown how the quenching constant formula must be generalized to be applicable in all kinetic situations.     

Numerical prediction and experiment on rubber creep and stress relaxation using time-dependent hyperelastic approach

Rubber is an excellent material for anti-vibration components in industry with a long term service. However, its time-dependent behaviour is undesirable in engineering applications. This article presents an engineering approach to evaluate the time-dependent responses, i.e., creep and stress relaxation, for rubber anti-vibration components. A time-dependent damage function was introduced into hyperelastic models. This function can be expressed in three forms. A typical rubber product and a dumbbell specimen were selected to validate the proposed approach. It has been shown that the predictions obtained from this method are consistent with the experimental data. It has also been established that the time-dependent response of industrial products can be predicted based on the responses from simple specimens, e.g., dumbbell specimen. In addition, it is possible to obtain a creep response based on a relaxation response and vice versa (by changing K value only) using the proposed approach, which has also been observed experimentally in the literature. The proposed function can also be easily incorporated into commercial finite element software (e.g., Abaqus). It has been demonstrated that the proposed method may be used at an appropriate design stage. Finally, the readers can select one of the three forms presented to perform assessments on the time-dependent responses evaluations for rubber anti-vibration products.     

Application of reference materials for quality assessment in neutron activation analysis-use of information theory

It is generally accepted that an analytical procedure can be regarded as an information production system yielding information on the composition of the analyzed sample. Thus, information theory can be useful and the quantities characterizing the information properties of an analytical method may be applied not only as evaluation criteria but also as objective functions in the optimization. The usability of information theory is demonstrated on the example of neutron activation analysis. Both precision and bias of NAA results are taken into account together with the possible use of reference materials for quality assessment. The influence of the above-mentioned parameters on information properties such as information gain and profitability of NAA results is discussed in detail. It has been proved that information theory is especially useful in choosing suitable reference materials for the quality assessment of routine analytical procedures not only with respect to matrix and analyte concentration in the sample but also to concentrations and uncertainties of certified values in the CRM used. In the extreme trace analysis, CRMs with relatively large uncertainties and very low certified concentrations can still yield rather high information gain of results.     

Deciphering the impact of PEG antifouling layer on surface attached functional peptides in regulating cell behaviors

In the ‘noise’ environment of culture medium, a medium length PEG antifouling layer (the OEG8 layer) can effectively resist the non-specific cell adhesion and present the optimal and genuine function of peptides in controlling cell behaviors.     

Recombinant HDL-like nanoparticles: a specific contrast agent for MRI of atherosclerotic plaques

A new contrast agent for MRI based on recombinant HDL-like nanoparticles has been prepared. It shows a great potential as a contrast agent for atherosclerotic plaques in a relative short time (24 h post-injection) as it is selective for the plaques and is an endogenous molecule. It also can distinguish between different types of plaques as the enhancement obtained is different, depending on plaque composition.     

MDAnalysis: A toolkit for the analysis of molecular dynamics simulations

MDAnalysis is an object‐oriented library for structural and temporal analysis of molecular dynamics (MD) simulation trajectories and individual protein structures. It is written in the Python language with some performance‐critical code in C. It uses the powerful NumPy package to expose trajectory data as fast and efficient NumPy arrays. It has been tested on systems of millions of particles. Many common file formats of simulation packages including CHARMM, Gromacs, Amber, and NAMD and the Protein Data Bank format can be read and written. Atoms can be selected with a syntax similar to CHARMM's powerful selection commands. MDAnalysis enables both novice and experienced programmers to rapidly write their own analytical tools and access data stored in trajectories in an easily accessible manner that facilitates interactive explorative analysis. MDAnalysis has been tested on and works for most Unix‐based platforms such as Linux and Mac OS X. It is freely available under the GNU General Public License from http://mdanalysis.googlecode.com . © 2011 Wiley Periodicals, Inc. J Comput Chem 2011     

An algorithm for geometry optimization without analytical gradients

A numerical algorithm for locating both minima and transition states designed for use in the ab initio program package GAUSSIAN 82 is presented. It is based on the RFO method of Simons and coworkers and is effectively the numerical version of an analytical algorithm (OPT = EF) previously published in this journal. The algorithm is designed to make maximum use of external second derivative information obtained from prior optimizations at lower levels of theory. It can be used with any wave function for which an energy can be calculated and is about two to three times faster than the default DFP algorithm (OPT = FP) supplied with GAUSSIAN 82.     

Concerning resistance network analogues for relaxation in multi-level systems and for double resonance experiments

The value of resistance network analogues as an aid to understanding relaxation in multi-level systems is re-emphasised. It is pointed out that analogues of the cross-saturation parameters which arise in the theoretical analysis of ENDOR and ELDOR experiments can be obtained from resistance measurements on an analogue circuit.     

Stabilization of 1,2-ditellurolane by 2,3,5,6-tetramethylnitrosobenzene (Nitrosodurene)

1,2-Ditellurolane is an extremely unstable heterocyclic compound which can be maintained in solution in the presence of nitrosodurene for several days. It is proposed on the basis of UV spectroscopy and ¹H NMR spectroscopy that a complex is formed which determines the stability of 1,2-ditellurolane. It is shown that stabilized 1,2-ditellurolane can be used in organic synthesis. Presented to Academician of the Russian Academy of Sciences Boris Aleksandrovich Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, 1736–1738, November, 2008.     

Structure-Activity Relationships in the Control of Chemical Risks

Abstract

Cluster significance analysis is a tool that allows the identification of ‘embedded clusters’ in QSAR datasets. It is successfully applied to an eye irritation data set to show that these data are indeed asymmetric. The method identifies five parameters that form an embedded cluster of eye irritants amongst non irritants, although full separation is not achieved. This method has considerable potential to identify potential non-linearity in toxicology data sets and for parameter reduction. It is shown also that this can be obtained relatively quickly with an analysis performed on 100,000 subsets containing the same information as an analysis on 1,000,000 subsets.     

氧化钙催化煤温和气化研究

报道了神木煤在小型流不反应器中,于４５０～７５０℃温度内,用ＣａＯ催化煤温和气化的研究。结果表明：添加ＣａＯ后,气体和半焦产率增加,焦油产率减少;ＣａＯ粒子对煤温和气化生成的焦裂解具有明显催化作用;可以明显增加气相中Ｈ２、ＣＨ４、Ｃ１～Ｃ５产率,降低半焦中Ｈ／Ｃ比,ＣａＯ还具有明显的固硫和固ＣＯ２作用,最后,推测了煤温和气化中ＣａＯ催化裂解多环芳烃侧链的机理。     

Deciphering the impact of PEG antifouling layer on surface attached functional peptides in regulating cell behaviors

It is highly desired to have bioactive surfaces for biomaterials and controllable interactions with cells.These functions were widely achieved by attaching functional peptides to the surface of biomaterials.It is well known that an antifouling layer can help reducing the nonspecific cell attachment.However,it is unclear how an antifouling PEG layer affects the function of peptides attached on material surface in controlling cell behavior.This highlight introduced the recent JACS paper from Prof.Liu and coworkers in addressing this question thoroughly.     

Calculation of phase diagrams of ternary M-Ga-Sb (M = In,Al) systems by convex hull approach

The ternary semiconductor phase diagrams of M-Ga-Sb (M = In, Al) are calculated by means of the convex hull approach. The software package TernAPI is tested as an effective tool for these purposes. The new facilities and advantages of this package are proven. It enables one to construct ternary phase diagrams based on thermodynamic properties of all phases existing in systems. The changes in phase region shapes and phase transformations with temperature can be studied by means of the TernAPI package. Selection of reliable thermodynamic models of solutions is of crucial importance for correct calculations of phase equilibria. It is shown that an adequate phase diagram can be constructed when a polynomial model of liquid solutions in the Al-Ga-Sb system is used.     

Hydrophobic Actuation of a DNA Origami Bilayer Structure

Amphiphilic compounds have a strong tendency to form aggregates in aqueous solutions. It is shown that such aggregation can be utilized to fold cholesterol‐modified, single‐layered DNA origami structures into sandwich‐like bilayer structures, which hide the cholesterol modifications in their interior. The DNA bilayer structures unfold after addition of the surfactant Tween 80, and also in the presence of lipid bilayer membranes, with opening kinetics well described by stretched exponentials. It is also demonstrated that by combination with an appropriate lock and key mechanism, hydrophobic actuation of DNA sandwiches can be made conditional on the presence of an additional molecular input such as a specific DNA sequence.