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71.
Zusammenfassung R. v. Eötvös hat für die Bestimmung von Lotrichtungsdifferenzen mit seiner Drehwaage zwei Verfahren angegeben, die aber nur unter Hinzuziehung astronomisch-geodätischer Messungen zum Ziel führen. Beide Verfahren sind sehr umständlich, und in der einschlägigen Literatur finden sich keine Hinweise, daß eines der genannten Verfahren seitEötvös nochmals angewandt wurde. — In Freiburg i. Br. wird zur Zeit eine Drehwaage erprobt, mit der voraussichtlich die direkte Messung des GradientenU zzs möglich sein wird. Es soll nun gezeigt werden, daß die Bestimmung der Lotrichtungsdifferenz zweier Feldpunkte mit Hilfe dieser Größe, ohne Zuhilfenahme von astronomisch-geodätischen Messungen, möglich ist.
Summary R. v. Eötvös has showed two methods for the measurement of differences between vertical lines with his torsion-balance. Both methods are only applicable, if they are connected with astronomic and geodetic measurements, and they are very troublesome. In the special publications are no remarks, that one of these methods everytime has been applied since the measurement ofEötvös. —At Freiburg i. Br. (Western Germany) now a new torsion-balance is built, with which foreseeable the direct measurement of the gradientU zzs will be possible. In the following publication will be demonstrated, that the fixation of differences between the vertical lines of two points of the gravity field of the earth is possible with this gradientU zzs without astronomic and geodetic measurements.
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72.
Summary The main subject of Ekman's most careful and detailed analysis of the current measurements of Armauer Hansen is to elucidate the periodical character of ocean currents. A survey of his results is given in table 2 and by means of an outline chartlet a comparison is made between the values which are derived from the observations on board Armauer Hansen and those attained by the reviewer by numerical calculation.
Les observations faites à bord du navire Armauer Hansen en 1930 à ses mouillages dans l'Atlantique et leur exploitation par V. W. Ekman
Résumé Le but principal de V. W. Ekman dans son analyse scrupuleuse et détaillée des mesures de courant est d'élucider le caractère periodique des courants océaniques. Les résultats les plus importants en sont donnés dans la table 2; en outre le rapporteur compare ces résultats empiriques d'Ekman avec ses propres calculs numériques en les confrontant dans une petite carte.


V. W. Ekmann, Studies on Ocean Currents. Geofysiske Publikasjoner Vol. XIX, No. 1, Bergen 1953.  相似文献   
73.
Zusammenfassung Stratigraphische und tektonische Untersuchungen im Gebiet zwischen Rheinbrohl/Brohl im NW und Leutesdorf/Namedy im SE erbrachten den Nachweis einer Großmulde aus Mittleren Siegener Schichten, deren Kern bei Oberhammerstein den Rhein quert. Die HENKE'sche Annahme eines Hönningen-Seifener Sattels im NW unseres Gebietes konnte bestätigt werden. Aus dem gegenseitigen Verhalten zwischen Faltung und Brüchen verschiedener Art ließ sich eine Altersfolge entwickeln, wobei die Einzelphasen sich einander zeitlich überschneidend ablösen. Diese zeitliche Folge wird von Falte zu Falte von den örtlichen Faktoren modifiziert, so durch die Verzopfung zweier Einzelfalten, wie an einem gut überschaubaren Beispiel gezeigt wird.  相似文献   
74.
Zusammenfassung Durch weitere experimentelle Untersuchungen wird festgestellt, dass das an destillierten Wassertropfen ermittelte Gefrierkernspektrum von speziellen Versuchsbedingungen unabhängig ist und auch für Wasserarten mit verschiedenen natürlichen oder künstlichen Verunreinigungen gilt. Es kann ausserdem in allen bisher im Laboratorium und in der Atmosphäre durchgeführten Untersuchungen über die Eiskeimbildung nachgewiesen werden. Dieser Befund stützt als notwendige Bedingung die Deutung des Gefrierkernspektrums durch Strukturänderungen des Wassers und besagt, dass im Laboratorium und in der Atmosphäre dieselben Gefrierkerne vorhanden sind und dass bei der atmosphärischen Eiskeimbildung auch nur die aus Untersuchungen im Laboratorium bekannten Besonderheiten des Gefrieveorgangs (im unterkühlten Wasser) vorliegen.
Summary Further experimental investigations demonstrate the «Gefrierkernspektrum», which was found for droplets from destilled water, to be independent from special experimental conditions and valid for sorts of water containing natural or artificial impurities, too. Furthermore it can be pointed out from all existing investigations on ice-nucleation, made in laboratory and in the atmosphere. This result supports, as a necessary condition, the interpretation of the «Gefrierkernspektrum» by means of changes in the structure of water itself and proves, that there are the same freezing nuclei both in the laboratory and the fre atmosphere and that ice-nucleation in the atmosphere holds but the same peculiarities of freezing (of supercooled water), known from laboratory work.
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75.
Zusammenfassung In der vorliegenden Arbeit wird eine Methode beschrieben, die es gestattet, mit Hilfe lackierter Glasplatten Kondensationskerntröpfchen oder andere Tröpfchen mit einem Durchmesser von 5 zu fixieren und dann elektronisch auszuzählen. Vorversuche, bei denen diese Methode angewendet wurde, machen es wahrscheinlich, dass bei Kondensationskernzählern, die nach dem Expansionsprinzip arbeiten, ein Teil der Kerne wegen ihrer Aktivität schon vor der Expansion als Wassertröpfchen ausfällt und damit der Zählung entgeht.
Summary In the present paper a method is described, which allows to fix droplets of condensation nucleus or other droplets (diameter 5 ) by means of varnished plates of glass and count them afterwards electronically. Preliminary experiments with this method show up the probability, that in the nucleus counter, working on the principle of expansion, some of the very active nucleus drops out before the expansion chamber is dilated and thus escapes registration.

Riassunto Nella presente ricerca si descrive un metodo il quale consente di fissare goccioline provenienti da nuclei di condensazione, o altre goccioline (diam. 5 ), su dischi di vetro verniciati, e in seguito di contarle elettronicamente. Prove eseguite con questo metodo rendono probabile che, in contatori di nuclei di condensazione che lavorano secondo il principio dell'espansione, una parte dei nuclei, in seguito alla loro stessa attività, cada sotto forma di goccioline d'acqua già prima dell'espansione e che quindi sfugga al conteggio.
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76.
In order to decide whether the seeing conditions at SAAO/Sutherland justify the erection of a 3.5 m telescope and also to compare Sutherland with the Gamsberg/Namibia site, a seeing campaign covering 15 months has been carried out. For direct comparison with the results of the seeing campaign at Gamsberg twenty years before the same QUESTAR telescope was employed. The seeing is determined by the scattering of the star-trail exposed on a film in the focal plane of the telescope. The campaign commenced in February 1992. Up to May 1993, data for 204 nights, that is 47.3% of the total number of nights, were collected. Due to wind speeds above 30 km h-1, 25 out of the 204 nights were not considered in the final reduction. The useful 179 nights are evenly distributed over the campaign period. The median seeing value for the whole period is = 0.52. There are differences during the year: the best season gives = 0.42, the worst = 0.67. Each night was divided into three intervals, although data for each of the three intervals were not always available. Generally, there is an improvement in the seeing during the course of a night. The results are compared to the seeing values of Gamsberg/Namibia and ESO/La Silla.  相似文献   
77.
The analytical expression of the gradient line, i.e. the perpendicular to the Moon's zonal equipotential surfaces is derived. Being a sensitive indicator of the geometric structure of the gravitational field, the shape of the trajectory, its direction field and curvature, the points of inflection, etc., are computed at elevations 0 km, 250 km, 1000 km and 10000 km above the Moon's surface. The numerical results were derived from the coefficients of Liu and Laing (1971) and are compared- whenever suitable - with the results obtained from the coefficients of Michaelet al. (1969).  相似文献   
78.
The San Francisco Estuary Regional Monitoring Program initiated surveillance monitoring to identify previously unmonitored synthetic organic contaminants in the San Francisco Estuary. Organic extracts of water samples were analyzed using gas chromatography-mass spectrometry in full scan mode. The major contaminant classes identified in the samples were fire retardants, pesticides, personal care product ingredients, and plasticizers. Evidence from the literature suggests that some of these contaminants can persist in the environment, induce toxicity, and accumulate in marine biota and in higher food chain consumers. The major sources of these contaminants into the marine environment are the discharge of municipal and industrial wastewater effluents, urban stormwater, and agricultural runoff. As a proactive effort, it is suggested that surveillance studies be used routinely in monitoring programs to identify and prevent potential problem contaminants from harming the marine environment.  相似文献   
79.
The capture efficiency map: the capture zone under time-varying flow   总被引:3,自引:0,他引:3  
Festger AD  Walter GR 《Ground water》2002,40(6):619-628
The capture zone or contributing area of a ground water extraction well can be defined as that portion of the aquifer from which the well draws its water. Accurate delineation of capture zones is important in many ground water remediation applications and in the definition of wellhead protection areas. Their mathematical delineation is often simplified by using quasi-steady-state models based on time-weighted average pumping rates and background hydraulic gradients. We present a new semianalytic approach for the definition of capture zones under transient-flow conditions. We then use this approach to evaluate the effects of time variations in the direction of the background hydraulic gradient on capture. Results are presented in the form of capture efficiency maps (CEMs). Although the area contributing to a given well is found to generally expand relative to the steady-state average capture zone when the gradient direction varies, the zone of 100% capture may expand or contract depending on site-specific conditions. We illustrate our CEM approach by applying it to the design of a plume containment system.  相似文献   
80.
Studies on the biodiversity and population dynamics of freshwater planktonic Gastrotricha have been carried out in conjunction with a physical–chemical analysis of the water in the Yaounde Municipal Lake (Cameroon, Central Africa) over a 14 months period (November 1996–December 1997). The results obtained allow to consider the Yaounde Municipal Lake as an eutrophic lake. It harbours eight species of Gastrotricha belonging to four genera (Chaetonotus, Dasydytes, Neogossea and Polymerurus) of the order Chaetonotida. This community was characterized by high abundances of populations, and was dominated by the genus Neogossea and Chaetonotusreaching up to 2000 ind. L−1. Polymerurus was mostly abundant at the almost anoxic bottom layers. The highest abundances were found mostly during the rainy season, when there is an important sedimentation process of organic matter, and were influenced by several different environmental factors such as dissolved oxygen, temperature and pH of the water.

Finally this community which may play an important role in the water bodies, is a potential water quality indicator.  相似文献   

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