Direct Measurement of Polaron Binding Energy in AMnO3 as a Function of the A Site Ionic Size by Photoinduced IR Absorption

Photoinduced IR absorption was measured in undoped (LaMn)_1–O₃ and (NdMn)_1–O₃. We observe broadening and a 44% increase of the midinfrared anti-Jahn–Teller polaron peak energy when La³⁺ is replaced with smaller Nd³⁺. The absence of any concurent large frequency shifts of the observed PI phonon bleaching peaks and the Brillouin-zone-center internal perovskite phonon modes measured by Raman and infrared spectroscopy indicate that the polaron peak energy shift is mainly a consequence of an increase of the electron phonon coupling constant with decreasing ionic radius r _A on the perovskite A site. This indicates that the dynamical lattice effects strongly contribute to the electronic band narrowing with decreasing r _A in doped giant magnetoresistance manganites.     

A Simple Prediction Method for the Surface Tension of Ionic Liquids as a Function of Temperature

In this study, a simple prediction method for the surface tension of ionic liquids (ILs) as a function of temperature is developed. Based on a database of experimental surface tension values collected from the literature, first a prediction scheme for the surface tension at a reference temperature of 298.15 K using only information on the density, molar mass, and anion type of the IL is suggested. By combination of this approach with the temperature dependence of the density, an extended prediction scheme describing the temperature dependence of the surface tension of ILs is recommended. The optimized prediction model for the surface tension allows for the prediction of about 3500 temperature-dependent experimental surface tension data of 226 different ILs with a standard deviation of about 7 %. In comparison with fluid-specific prediction methods found in the literature, the developed simple empirical prediction model requires only easily accessible parameters and can be applied for ILs with arbitrary cation and anion combinations. Thus, the proposed prediction method seems to be a valuable engineering tool for the quantitative estimation of the surface tension of ILs.     

Temperature Effects on the Self-trapping Energy of a Polaron in a GaAs Parabolic Quantum Dot

The temperature and the size dependences of the self-trapping energy of a polaron in a GaAs parabolic quantum dot are investigated by the second order Rayleigh-Schrodinger perturbation method using the framework of the effective mass approximation. The numerical results show that the self-trapping energies of polaron in GaAs parabolic quantum dots shrink with the enhancement of temperature and the size of the quantum dot. The results also indicate that the temperature effect becomes obvious in small quantum dots     

浅谈能源计量在节能减排中的作用及现状

能源、资源、环境是人类生存和发展的基础。自工业革命以来,资源的大规模开发利用创造了辉煌的物质文明,同时也带来了世界性的资源环境问题。基于严峻的资源环境形势,我国提出要用科学发展观统筹经济社会发展全局,要通过结构性调整和发展方式转变来破解资源环境难题,节能减排被作为一项操作层面的具体措施和抓手摆在了突出位置。而企业节能减排必须对能源进行量化管理,量化管理的手段就是计量,就现有的节能减排政策文献的内容看,大多只针对某一具体政策进行论述,很少有论述能源计量在节能减排中的作用,忽略能源计量的基础作用。本文主张在目前的大环境下,应该认识到节能减排与能源计量的关系,发挥能源计量的作用,改变传统的节能减排的做法,有条不紊推进节能减排目标的实现。     

The Thermal Conductivity of Superfluid 3He in Aerogel: A Measurement of the Energy Gap

Transport properties of superfluid ³ He in aerogel are governed by a fixed mean free path set by the typical dimensions of the strand separation. We describe preliminary measurements of the thermal conductivity of superfluid ³ He confined in 98% silica aerogel. The majority of the measurements are made in relatively high magnetic fields where the superfluid within the aerogel is in the A-phase like state. Since the quasiparticle mean free path is fixed, the temperature dependence of the thermal conductivity depends only on the superfluid energy gap and on the texture in the case of the A-phase. The results so far obtained are broadly consistent with the aerogel-confined superfluid having a temperature dependent energy gap close to the BCS prediction although there are significant deviations at the lowest temperatures.     

Measurement of the Sensitivity Function in a Time-Domain Atomic Interferometer

We present here an analysis of the sensitivity of a time-domain atomic interferometer to the phase noise of the lasers used to manipulate the atomic wave packets. The sensitivity function is calculated in the case of a three-pulse Mach-Zehnder interferometer, which is the configuration of the two inertial sensors we are building at the Laboratoire National de Metrologie et d'Essais-Systeme de References Temps-Espace. We successfully compare this calculation to experimental measurements. The sensitivity of the interferometer is limited by the phase noise of the lasers as well as by residual vibrations. We evaluate the performance that could be obtained with state-of-the-art quartz oscillators, as well as the impact of the residual phase noise of the phase-locked loop. Requirements on the level of vibrations are derived from the same formalism.     

Dissolution Properties of Piroxicam Powders and Capsules as a Function of Particle Size and the Agglomeration of Powders

The poor dissolution characteristics of relatively insoluble drugs have long been a problem to the pharmaceutical industry. An example is piroxicam, a highly potent anti-inflammatory agent. In many countries, a large number of generic piroxicam products are available to the prescriber. The aim of this study was to investigate the cause of the dissolution problems experienced by manufacturers of generic piroxicam capsules. Two raw material batches and the dissolution properties of several piroxicam capsules were studied. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) results showed that the two raw material samples were identical with respect to polymorphic modification. The particles of powder 1 were smaller than those of powder 2, but the dissolution of powder 1 was much slower than that of powder 2. The dissolution results for the capsules showed a marked difference among different brands, with capsule C not meeting the USP tolerance. Adding surfactant to the dissolution medium increased the dissolution of both powder 1 and capsule C. Failure of powder 1 or capsule C to meet USP dissolution criteria could result in differences in product efficacy, as well as in potential side effects. Such observations should be taken into account along with other relevant considerations when decisions regarding the generic substitution of oral piroxicam products are made.     

地热驱动吸收式制冷技术在广东地热开发中的应用探讨

本文从分析广东省地热资源状况出发 ,介绍地热驱动吸收式制冷技术的应用意义 ,探讨其在广东乃至整个南方地热开发中的应用前景和经济效益     

The Effective Mass and Binding Energy of 4He in 3He in the Fermi Liquid Region

We have measured the solubility of ⁴ He in liquid ³ He down to about 40 mK and at pressures from zero up to 24 atm. The solubility was obtained from the thickness of the superfluid film in contact with unsaturated solutions of ⁴ He in ³ He as a function of temperature. By fitting the solubility data to Fermi liquid theory, we obtained the parameters m ₄ ^* and as a function of pressure. Here, m ₄ ^* is the effective mass of ⁴ He in liquid ³ He and the difference in binding energy between ⁴ He in pure ⁴ He and ⁴ He in liquid ³He. This difference has a minimum near 10 atm. The average of the results for m ₄ ^* , at different pressures, is (1.3 ± 0.2)m ₄. This agrees with the many body calculations of de Saavedra et al., and with the Stokes hydrodynamic mass using the partial volume of ⁴ He in ³ He, v ₄ ^* . The partial volume was obtained by taking the derivative of with respect to pressure.     

简论工业企业能源计量管理体系的构建

节能降耗是工业经济可持续发展的重要前提,国家各级政府通过政策法规为工业企业制定了节能降耗的任务和目标,明确了能源计量工作的具体要求和责任。企业据此应形成明确的意识与科学的认识,采取合理的方法与有力的措施,通过对能源计量一系列具体工作内容的建设,构建企业能源计量管理体系。从而促进企业技术进步,提升企业市场竞争力,为企业长远发展提供重要基础平台。     

原子吸收光谱法测定茶叶中铜的测量不确定度评定

通过对测定茶叶中铜含量的不确定度评定分析,找出引起不确定度产生的主要因素,评定确认由最小二乘法拟合校准标准曲线及测量重复性是影响结果的最主要因素,使用标准物质（标准储备液）及稀释过程引入的不确定度也应引起重视,此方法对类似的火焰原子吸收法测定样品中待测元素含量有借鉴和参考作用。     

Effect of Core Electrons in Defining the Total Energy,Correlation Energy,and Binding Energy of Graphene,Graphite, and Diamond: a First-Principles Study

Effects of core electrons on total energy, correlation energy, and binding energy of graphene, graphite, and diamond have been investigated along with density functional theory (DFT) calculations at the PBE level of theory using all electron and frozen-core calculations. For these calculations, correlation-consistent basis sets cc-pVXZ and cc-pCVXZ have been used where X is the cardinal number that represents the maximum angular momentum number in the basis set. By taking the difference between all electron and frozen-core calculations, core-electron binding energy contribution for each basis set has been obtained. It has been shown that to reduce the effects of core electrons, large basis sets should be used.     

Investigations Regarding the Measurement of the Modulation Transfer Function and Possibilities for its Designation by a Numerical Value

A step by step analysis of the photographic image forming process is used to explain the possible restrictions on the range of validity of the modulation transfer function (MTF). In general the MTF characterizes a film-developer-system within a given range of exposure and contrast. Other functions to describe the spatial frequency response are discussed. The use of photographic film as a photometer is distinguished from the use as image reproducer on behalf of the use of the proper signal functions. The interaction between the aperture of the exposing pencils and the thickness of the coating is investigated experimentally and a simple formula is proposed to describe it. The possibilities of characterizing the MTF by one single numerical value are discussed.     

Size as a factor in the brittle-ductile transition and the strength of some materials

Attention is called to a new phenomenon: in certain materials, specimen size (or, its energy-storage capacity) influences its brittle-ductile transition and strength. This effect is not the recognized statistical one (which only concerns the nucleation of fracture), but derives from the strain-energy in the system and concerns the stability of slow-growing cracks after nucleation. Recent experimental observations, in which this effect was noted, are cited and a theory proposed to account for them. This theory is based on the fact that a highly unstable equilibrium exists between the respective rates of strain-energy release and energy demand. When the system is over-stocked with strain-energy, any sudden drop in energy demand creates an excess of energy released. This then takes the form of kinetic energy capable of doing work against the remaining resistance, in turn, resulting in a lower fracture load and reduced ductility. Specimen size enters these considerations only in so far as it governs the amount of stored energy; consequently the effect is most pronounced in flexure.Although the effect was so far observed in materials with moderate ductility, it is speculated that fine techniques might reveal its presence both ideally brittle and ideally ductile materials.

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Zusammenfassung Augenmerk wird auf ein neues Phenomen gelenkt: In gewissen Werkstoffen beeinflusst die Grosse des Prüfkörpers (oder sein Energiespeicherungsvermögen) den Uebergang vom spröden zum verformbaren Verhalten, Diese Erscheinung hat nichts mit dem bekannten statistischen Effekt zu' tun (der sich nur auf den Bruchanriss bezieht), sondern ist eine Folge der Formänderungsenergie in dem System und äussert sich in der Stabilität each dem ersten Anriss langsam fortschreitender Risse. Neuere Beobachtungen, in dessen dieser Effekt festgestellt wurde, werden angeführt und eine Theorie wird aufgestellt, die ihnen Rechnung tragen soll, Diese Theorie gründet sich auf die Tatsache, dass ein hochgradig labiles Gleichgewicht zwischen der jeweiligen Freisetzungsrate der Verformungsenergie und dem Energiebedarf besteht. Wenn das System mit Verformungsenergie überladen ist, verursacht jeder plötzliche Abfall des Energiebedarfs einen Uebersehuss freigesetzter Energie. Dieser tritt als kinetische Energie in Erscheinung, die imstande ist, sich in Ueberwindung des verbleibenden Widerstandes umzusetzen und so zu einer niedrigeren.Bruchlast and zu verringerter Verformbarkeit führt. Die Grösse des Prüfkörpers erscheint in diesen Betrachtungen nur insofern, als sie den Betrag der verfügbaren Energiespeicherung bestimmt; demgemäss zeigt sich der Effekt am stärksten bei der Biegungsbeanspruchung.Obwohl der Effekt bis jetzt nur in Werkstoffen von mässiger Verformbarkeit beobachtet wurde, wird vetmutet, dass Feinmesstechniken sein Auftreten sowohl in ideal sproden als auch in ideal verformbaren Werkstoffen nachweisen könnten.

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Résumé On attire l'attention sur un phénomène nouveau: pour certains materiaux, la dimension des éprouvettes (ou leur capacité d'accumulation d'énergie) possède une influence sur leur résistance et leurs propriétés de transition de ductilité. Cet effet ne procède pas de l'aspect statistique qui concerne la formation du premier nodule de rupture, mais est en rélation avec l'énergie de déformation dans le système, et intéresse la stabilité des fissures en cours d'extension lente après nucléation. On cite des observations expérimentales récentes, où un tel effet dimensionnel a été relevé, et l'on propose une théorie pour entenir compte.Cette théorie est basée sur le fait qu'il existe un état d'équilibre extrêmement instable entre les pour-centages respectifs d'énergie libérée et d'énergie requise pour la fissuration. Lorsque l'énergie de déformation est surabondante dans le système, toute chute soudaine de l'énergie requise se traduit par un excès brutal d'énergie libéree. Celle-ci prend la forme d'une énergie cinétrique qui est à même d'effectuer un travail vis-à-vis de la résistance offerte á la rupture, ce qui entrâine, à son tour, un abaissement de la charge de rupture et une diminution de la ductilité. La dimension de l'éprouvette n' intervient dans ce phénomène que pour autant qu' elle régisse la quantité d' energie accumulée; l'effet en est donc plus prononcé dans les essais de flexion.Malgré que l'effet dimensionnel des éprouvettes sur les propriétés de résistance á la rupture fragile n'a, jusqu' ici, été constaté que pour des matériaux de ductilité moyenne, on pense qu'un affinage des techniques expérimentales est susceptible de le révéler également dans les matériaux idéalement fragiles et idéalement ductiles.

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On leave from Douglas Aircraft Co., Inc., Missile and Space System Division, Santa Monica, California.