Reciprocating flow ion exchange part II: Application to saline water softening

The “hardness” components in sea water can be considerably reduced by means of a new economical fixed bed technique called “Reciprocating Flow Ion Exchange”, when used in conjunction with a closed cycle exchanger-evaporator system. Removal of 87.9% of the calcium and 54.5% of the magnesium in sea water has been obtained with an overall flow rate of 5.0 U. S. g. p. m./sq. ft. Results from bench scale and a 5,000 g. p. d. pilot plant were identical. The virtually continuous cyclic steady-state process requires a small amount of exchanger (0.5 to 2% of the usual ion exchange methods, such as conventional fixed beds or fluidized beds). The effects of variation in operating parameters are discussed.     

Einfluß der Produkteigenschaften auf die Trocknung

Influence of Product Properties on Drying. A number of items of information are required for selection and design of a drying process. Thermodynamic equilibrium as well as heat and mass transfer are the traditional prerequisites for describing the drying operation. In the development of a drying process further specific properties of the product must be known. These properties, such as chemical reactions or sticking properties, greatly reduce the number of possible drying processes. For this reason, the measurement of these properties plays an important role in the development of a drying process. Many of the bench scale tests in use do not have a physical basis, but have been developed empirically because the physical context is often unknown. Yet a number of physically well-defined methods are available for product characterization. In practical work a combination of empirical and scientifically defined methods is used.     

高强度高压绝缘子产品质量同其结构性能的重要关系(续)——制造者和用户应共同掌握的规则和指标(第二部分)

6　各种电瓷结构分析实例证实结构的差别下面介绍各种电瓷结构分析的结果。从扫描电镜照片 (ＲＥＭ)的判读中可见到这些材料的差别。试样ａ:日本瓷绝缘子Ｃ1 1 0 /1 1 2 ,制造年代 1 997试样ｂ :西门子瓷绝缘子Ｃ1 2 0 ,Ｃ1 3 0 ,制造年代 2 0 0 1试样ｃ:高强度矾土瓷绝缘子 ,西门子 2 0 0 1开发陶瓷岩相试样的制备系经多级金刚石研磨和抛光以及化学浸蚀。为判定气孔状态 ,对磨片作了透光照片 ,在其光亮区放大倍数为 1 0 0∶1 ,而且扫描电镜照片放大倍数为2 0 0∶1。图 5ａ　试样ａ光片的ＬＭ(透光显微镜 )和ＲＥＭ(扫描电镜 )图象 ,放大倍…     

Regulation of phosphatidylinositol turnover,calcium metabolism and enzyme secretion by phorbol dibutyrate in neutrophils

The action of the tumor promoter, phorbol 12,13-dibutyrate (PDBu), on rabbit peritoneal and human neutrophils is associated with stimulation of¹⁴C-arachidonic acid incorporation into phospholipids within 1–2 min. Stimulated¹⁴C-arachidonate incorporation was relatively selective for phosphatidylinositol (PI) in rabbit neutrophils. In contrast, the secretory response of human neutrophils to PDBu coincided with stimulated label incorporation into phosphatidylserine (PS), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA) and PI. Significant increases in label incorporation were observed with PDBu concentrations as low as 2 nM, and the dose response of stimulated label incorporation paralleled that of evoked lysozyme secretion. A parallel, but partial, inhibition of PDBu-stimulated PI labeling and enzyme release was observed after exposing rabbit neutrophils to calcium-deprived medium, whereas calcium deprivation failed to significantly depress either of these stimulant actions of PDBu in human neutrophils. Further, in rabbit neutrophils PDBu elicited an increase in cell associated⁴⁵Ca. However, PDBu was unable to promote the incorporation of³²P orthophosphate into PI or enhance phospholipase A₂ activity in broken cells. These findings suggest that one expression of the interaction between phorbol esters and their receptors on neutrophils involves the turnover of arachidonic acid in phospholipids. This stimulated turnover of arachidonate may be a critical step in the cascade of events associated with neutrophil activation.     

The allelopathic mechanisms of dominance in bracken (Pteridium aquilinum) in Southern California

Bracken,Pteridium aquilinum, exerts a strong dominance over associated plants throughout much of its worldwide range. Associated plants are often severely inhibited or even excluded from dense stands of the fern. This study investigated the various aspects of herb suppression in bracken stands and assessed the contribution of the various forms of interference between plants to the establishment and maintenance of bracken dominance. It was shown that competition for soil moisture, light, and nutrients could not account for the lack of herbs in bracken stands. Further, uniformity of soil pH, texture, water-holding capacity, and organic matter content ruled out variability in physical factors as a cause. Baiting and trapping experiments showed that the higher concentration of animal activity inside the bracken stands contributed significantly to the pattern of herb suppression, but only against select species. The maintenance of this pattern in the animal-free Santa Cruz Island stands indicates the importance of another factor, allelopathy. It was found that phytotoxins leached from the dead, standing bracken fronds with the first few rains of the wet season were largely responsible for herb suppression. These toxins were isolated in raindrip and from soil inside the fern stands. Removal of the fronds from the stand before the rains could leach them resulted in reinvasion by the herbs after several seasons, and, conversely, placing fronds over the herbs in the grassland brought about herb inhibition. A number of known allelopathic chemicals were tentatively identified from bracken leachates. The importance of the interaction of allelopathy with other factors of plant interference is illustrated by bracken.     

护肤品的功效性评价方法综述

现代科学技术,尤其是生物技术和计算机技术的飞速发展和广泛应用,给化妆品行业带来了全新的发展机遇,赋予化妆品以一定的功效性是新世纪化妆品发展的重要趋势.近20年来,人们对化妆品的要求已从洁肤、润肤为目的的基础护肤品向美白、祛皱为目的的功效性化妆品方向发展.     

A mixed boundary-value problem of elasticity with parabolic boundary

Summary The mixed boundary-values problem of elasticity with parabolic boundary when the prescribed displacement is parabolic has been reduced to the solution of the non-homogeneous Hilbert problem following the method of complex variable. The result has been compared with that obtained byParia [5] for parabolic boundary with prescribed constant displacement as a particular case.

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Zusammenfassung Das gemischte Randwertproblem der Elastizitätstheorie wird für parabolische Berandung auf die Lösung des inhomogenen Hilbert-Problems unter Benützung der komplexen Methode zurückgeführt. Die Randverschiebung wird durch ein Polynom zweiten Grades dargestellt. Das Ergebnis wird mit dem vonParia [5] verglichen, das als Sonderfall konstante Verschiebungen am parabolischen Rand vorschreibt.

     

Approximation mit Exponentialsummen

Zusammenfassung Für die Approximation mit Exponentialsummen ist die beste Approximation imTschebyscheffschen Sinne eindeutig, abgesehen von bisher nicht erkannten Ausnahmen. Eindeutigkeit liegt dagegen immer bei der Anpassung mit positiven Exponentialsummen vor. Daß diese Familie eine andere Struktur hat als die bekannten Verallgemeinerungen linearer Funktionenfamilien, zeigt sich am Charakter des Alternantenkriteriums.

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Summary In this paper we investigate the approximation by sums of exponentials in the sense ofChebyshev. The best approximation is shown to be unique apart from exceptions not previously recognized. However, there is always uniqueness, when only sums of positive exponentials are considered. This family has a structure which is different from that of other generalizations of linear families of functions. This feature is reflected in the criterion on the alternations of the error curve.

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Kernforschungszentrum Karlsruhe, Institut für Neutronenphysik und Reaktortechnik     

Some theorems of the eddy-current theory

Contents In the paper, theorems for the electric vector potentialT and magnetic scalar potentialU are discussed, which occur in the boundary-value problems for eddy currents induced in a conducting block by an external magnetic field. Uniqueness of the solution is examined. An integral representation of the scalar potentialU is derived for a nonmagnetic conductor. It is shown that for a thin metallic shell the integrodifferential equation results from general formulas related to the block.

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Einige Theoreme der Wirbelstromtheorie

Übersicht In der Arbeit werden drei Theoreme für das elektrische VektorpotentialT und das magnetische SkalarpotentialU beschrieben, die in den Randwertaufgaben für in einem metallischen Block durch das äußere magnetische Feld induzierte Wirbelströme auftreten. Es wird bewiesen, daß eine solche Randwertaufgabe eine eindeutige Lösung hat, wenn das Vektorpotential auf dem Rand gleich Null ist. Eine Integralrepräsentation des Skalarpotentials wird abgeleitet. Es wird gezeigt, daß die Integrodifferentialgleichung für eine dünne metallische Hülle aus allgemeinen, den Block betreffenden Formeln hervorgeht.

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List of principal symbols e coordinate unit vector - H magnetic intensity - J current density - T electric vector potential - U magnetic scalar potential - permeability - conductivity - V boundary of regionV