Occurrence and distribution of phthalate esters in riverine sediments from the Pearl River Delta region,South China   总被引：5，自引：0，他引：5  

Hong Liu  Kunyan Cui  Feng Zeng  Lixuan Chen  Yating Cheng  Huiru Li  Shuocong Li  Xi Zhou  Fang Zhu  Gangfeng Ouyang  Tiangang Luan  Zunxiang Zeng 《Marine pollution bulletin》2014

Sixty-eight sediment samples collected from Dongjiang River, Xijiang River, Beijiang River and Zhujiang River in the Pearl River Delta (PRD) region, Southern China, were analyzed for 16 phthalate esters (PAEs). PAEs were detected in all riverine sediments analyzed, which indicate that PAEs are ubiquitous environmental contaminants. The Σ₁₆PAEs concentrations in riverine sediments in the PRD region ranged from 0.567 to 47.3 μg g⁻¹ dry weight (dw), with the mean and median concentrations of 5.34 μg g⁻¹ dw and 2.15 μg g⁻¹ dw, respectively. Elevated PAEs concentrations in riverine sediments in the PRD region were found in the highly urbanized and industrialized areas. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs, with the mean and median concentrations of 1.12 μg g⁻¹ dw, 0.420 μg g⁻¹ dw and 3.72 μg g⁻¹ dw, and 0.429 μg g⁻¹ dw, 0.152 μg g⁻¹ dw and 1.55 μg g⁻¹ dw, respectively, and accounted for 94.2–99.7% of the Σ₁₆PAEs concentrations. Influenced by local sources and the properties of PAEs, a gradient trend of concentrations and a fractionation of composition from more to less industrialized and urbanized areas were discovered. As compared to the results from other studies, the riverine sediments in the PRD region were severely contaminated with PAEs. Information about PAEs contamination status and its effect on the aquatic organisms in the PRD region may deserve further attention.  相似文献   

Air-sea CO₂ fluxes in the southern Yellow Sea: An examination of the continental shelf pump hypothesis   总被引：1，自引：0，他引：1  

Liang Xue  Longjun Zhang  Wei-Jun CaiLi-Qing Jiang 《Continental Shelf Research》2011,31(18):1904-1914

The southern Yellow Sea (SYS), located to the north of the East China Sea (ECS), was considered part of the ECS when Tsunogai et al. (1999) proposed the “continental shelf pump” (CSP) hypothesis. However, the original CSP carbon dioxide (CO₂) uptake flux (2.9 mol C m⁻² yr⁻¹) appears to have been overestimated, primarily due to the differences between the SYS and the ECS in terms of their CO₂ system. In this paper, we estimated air-sea CO₂ fluxes in the SYS using the surface water partial pressure of CO₂ (pCO₂) measured in winter, spring, and summer, as well as that estimated in fall via the relationship of pCO₂ with salinity, temperature, and chlorophyll a. The results indicate that overall, the entire investigated area was a net source of atmospheric CO₂ during summer, winter, and fall, whereas it was a net sink during spring. Spatially, the nearshore area was almost a permanent CO₂ source, while the central SYS shifted from being a CO₂ sink in spring to a source in the other seasons of the year. Overall, the SYS is a net source of atmospheric CO₂ on an annual scale, releasing ∼7.38 Tg C (1 Tg=10¹² g) to the atmosphere annually. Thus, the updated CO₂ uptake flux in the combined SYS and ECS is reduced to ∼0.86 mol C m⁻² yr⁻¹. If this value is extrapolated globally following Tsunogai et al. (1999), the global continental shelf would be a sink of ∼0.29 Pg C yr⁻¹, instead of 1 Pg C yr⁻¹ (1 Pg=10¹⁵ g).The SYS as a net annual source of atmospheric CO₂ is in sharp contrast to most mid- and high-latitude continental shelves, which are CO₂ sinks. We argue that unlike the ECS and the North Sea where carbon on the shelf could be exported to the open ocean, the SYS lacks the physical conditions required by the CSP to transport carbon off the shelf effectively. The global validity of the CSP theory is thus questionable.  相似文献   

Laws,place, history and the interpretation of landforms          下载免费PDF全文

Jonathan D. Phillips 《地球表面变化过程与地形》2017,42(2):347-354

The state of an Earth surface system (ESS) is determined by three sets of factors: laws, place, and history. Laws ( L = L₁, L₂, . . . , L_n) are the n general principles applicable to any such system at any time. Place factors ( P = P_1, P_2, . . . , P_m) are the m relevant characteristics of the local or regional environment. History factors ( H = H₁ , H₂, . . . , H_q) include the previous evolutionary pathway of the ESS, its stage of development, past disturbance, and initial conditions. Geoscience investigation may focus on laws, place, or history, but ultimately all three are necessary to understand and explain ESS. The LPH triad is useful as a pedagogical device, illustrated here via application to explaining the world's longest cave (Mammoth Cave, KY). Beyond providing a useful checklist, the LPH framework provides analytical traction to some difficult research problems. For example, studies of the avulsions of three southeast Texas rivers showed substantial differences in avulsion regimes and resulting alluvial morphology, despite the proximity and superficial similarity of the systems. Avulsions are governed by the same laws in all cases [ L (A) = L (B) = L (C)], and the three rivers have undergone the same sea‐level, climate, and tectonic histories, as well as the same general anthropic impacts [ H (A) ≈ H (B) ≈ H (C)]. Though regional environmental controls are similar, local details such as the location of the modern main channel relative to Pleistocene meander channels differ, and thus these place factors explain the differences between the rivers. The LPH framework, or similar types of reasoning, is implicit in many types of geoscience analysis. Explicit attention to the triad can help solve or address many specific problems and remind us of the importance of all three sets of factors. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Vortical and wave modes in 3D rotating stratified flows: random large-scale forcing     

Jai Sukhatme  Leslie M. Smith 《地球物理与天体物理流体动力学》2013,107(5):437-455

Utilizing an eigenfunction decomposition, we study the growth and spectra of energy in the vortical (geostrophic) and wave (ageostrophic) modes of a three-dimensional (3D) rotating stratified fluid as a function of ε = f/N, where f is the Coriolis parameter and N is the Brunt–Vaisala frequency. Throughout, we employ a random large-scale forcing in a unit aspect ratio domain and set these parameters such that the Froude and Rossby numbers are roughly comparable and much less than unity. Working in regimes characterized by moderate Burger numbers, i.e. Bu = 1/ε² < 1 or Bu ≥ 1, our results indicate profound change in the character of vortical and wave mode interactions with respect to Bu = 1. Indeed, previous analytical work concerning the qualitatively different nature of these interactions has been in limiting conditions of rotation or stratification domination (i.e. when Bu ? 1 or Bu ? 1, respectively). As with the reference state of ε = 1, for ε < 1 the wave mode energy saturates quite quickly and the ensuing forward cascade continues to act as an efficient means of dissipating ageostrophic energy. Further, these saturated spectra steepen as ε decreases: we see a shift from k ^?1 to k ^?5/3 scaling for k _f < k < k _d (where k _f and k _d are the forcing and dissipation scales, respectively). On the other hand, when ε > 1 the wave mode energy never saturates and comes to dominate the total energy in the system. In fact, in a sense the wave modes behave in an asymmetric manner about ε = 1. With regard to the vortical modes, for ε ≤ 1, the signatures of 3D quasigeostrophy are clearly evident. Specifically, we see a k ^?3 scaling for k _f < k < k _d and, in accord with an inverse transfer of energy, the vortical mode energy never saturates but rather increases for all k < k _f . In contrast, for ε > 1 and increasing, the vortical modes contain a progressively smaller fraction of the total energy indicating that the 3D quasigeostrophic subsystem, though always present, plays an energetically smaller role in the overall dynamics. Combining the vortical and wave modes, the total energy for k > k _f and ε ≤ 1 shows a transition as k increases wherein the vortical modes contain a large portion of the energy at large scales, while the wave modes dominate at smaller scales. There is no such transition when ε > 1 and the wave modes dominate the total energy for all k > k _f .  相似文献   

A Monte Carlo simulation of the effect of ion self-collisions on the ion velocity distribution function in the high-latitude F-region     

I. A. Barghouthi  A. R. Barakat  R. W. Schunk 《Annales Geophysicae》1994,12(10-11):1076-1084

Non-Maxwellian ion velocity distribution functions have been theoretically predicted and confirmed by observations, to occur at high latitudes. These distributions deviate from Maxwellian due to the combined effect of the E×B drift and ion-neutral collisions. The majority of previous literature, in which the effect of ion self-collisions was neglected, established a clear picture for the ion distribution under a wide range of conditions. At high altitudes and/or for solar maximum conditions, the ion-to-neutral density ratio increases and, hence, the role of ion self-collisions becomes appreciable. A Monte Carlo simulation was used to investigate the behavior of O⁺ ions that are E×B-drifting through a background of neutral O, with the effect of O⁺ (Coulomb) self-collisions included. Wide ranges of the ion-to-neutral density ratio n _i /n _n and the electrostatic field E were considered in order to investigate the change of ion behavior with solar cycle and with altitude. For low altitudes and/or solar minimum (n _i /n _n \leq10^?5), the effect of self-collisions is negligible. For higher values of n _i /n _n , the effect of self-collisions becomes significant and, hence, the non-Maxwellian features of the O⁺ distribution are reduced. For example, the parallel temperature T _i\Vert increases, the perpendicular temperature T _i⊥ decreases, the temperature anisotropy approaches unity and the toroidal features of the ion distribution function become less pronounced. Also, as E increases, the ion-neutral collision rate increases, while the ion-ion collision rate decreases. Therefore, the effect of ion self-collisions is reduced. Finally, the Monte Carlo results were compared to those that used simplified collision models in order to assess their validity. In general, the simple collision models tend to be more accurate for low E and for high n _i /n _n .  相似文献   

Does heavy oil pollution induce bacterial diseases in Japanese flounder Paralichthys olivaceus?   总被引：1，自引：1，他引：0  

Jun-Young Song  Kei Nakayama  Yasunori Murakami  Sung-Ju Jung  Myung-Joo Oh  Satoru Matsuoka  Hidemasa Kawakami  Shin-Ichi Kitamura   《Marine pollution bulletin》2008,57(6-12):889

As basic research for the effect of heavy oil on the fish immune system, in this study, the number of leukocyte was counted in Japanese flounder Paralichthys olivaceus, after exposure to heavy oil at a concentration of 30 g/8 L for 3 days. To compare the numbers of bacteria in the skin mucus between oil-exposed and control fish, viable bacteria were enumerated by counting colony forming unit (CFU). Compared with 5.79 ± 1.88 × 10⁷ leukocytes/mL in the controls, the exposed fish demonstrated higher counts, averaging 1.45 ± 0.45 × 10⁸ cells/mL. The bacterial numbers of control fish were 4.27 ± 3.68 × 10⁴ CFU/g, whereas they were 4.58 ± 1.63 × 10⁵ CFU/g in the exposed fish. The results suggest that immune suppression of the fish occurred due to heavy oil stressor, and bacteria could invade in the mucus, resulting in the increasing leukocyte number to prevent infectious disease.  相似文献   

Features of seismicity in Xinjiang and its possible reason after the Yutian M_S7.4 earthquake, 2008          下载免费PDF全文

Qiong Wang  Haitao Wang  Aiguo Xia 《地震科学（英文版）》2009,22(6):615-622

The paper discusses quantitatively the influence of the Yutian M_S7.4 earthquake of March 21, 2008 and Wuqia M_S6.9 earthquake of October 5, 2008 on regional seismicity in Xinjiang, and explains primarily the possible reason of earthquake activity feature in Xinjiang after the Yutian M_S7.4 earthquake by analyzing the static Coulomb failure stress change produced by the Yutian M_S7.4 earthquake and Wuqia M_S6.9 earthquake, and the seismicity feature of M_S?≥3 earthquakes in the positive Coulomb stress change region of Kashi-Wuqia joint region, the central segment of Tianshan Mountain and Kalpin block. The result shows that the Yutian M_S7.4 earthquake of March 21, 2008, may encourage the Wuqia M_S6.9 earthquake of October 5, 2008, and the Yutian M_S7.4 earthquake and Wuqia M_S6.9 earthquake may change the seismicity state in the central segment of Tianshan Mountain, Kalpin block and Kashi-Wuqia joint region, and encourage the subsequent M_S?≥3 earthquakes.

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L'énergie des perturbations et les deux régimes du mouvement des fluides en météorologie synoptique     

Prof. Ing. Antonio Giao 《Pure and Applied Geophysics》1955,32(1):107-123

Résumé On commence par déduire l'équation thermo-hydrodynamique d'une masse finie quelconque du fluide. Cette équation réalise la synthèse des équations du mouvement, de l'équation de continuité, de l'équation qui exprime le premier principe de la thermodynamique et de l'équation d'état. Sous sa forme première, elle ne se prête pas, pour plusieurs raisons; à l'étude des transformations d'énergie dans une masse donnée. En considérant cependant la décomposition du mouvement réel en mouvement de base et perturbation, et en appliquant l'équation thermo-hydrodynamique à une même masse dans le mouvement réel et dans le mouvement de base (c'est-à-dire, à une masse dont la surface limite se déplace de la même manière dans le mouvement réel et dans le mouvement de base), on arrive facilement à une nouvelle forme beaucoup plus simple, quoique rigoureuse, de l'équation thermohydrodynamique. Cette nouvelle forme exprime la perturbation de l'énergie cinétique du mouvement autour du centre de gravité de la masse en fonction de la perturbation de son enthalpie (terme margulésien) et de la perturbation de la dissipation d'énergie dans la masse par les efforts de frottement. D'où un premier résultat central du mémoire qui s'énonce en disant que la perturbation de la dissipation d'énergie contribue nécessairement et efficacement, dans certains volumes de l'atmosphère, à une augmentation de l'énergie cinétique des perturbations.La variation de l'enthalpie peut être exprimée en fonction du mouvement du centre de gravité de la masse. On montre alors que la variation temporelle de la perturhation de l'enthalpie est nulle pour toute masse dont le mouvement de la surface limite n'a pas de perturbation. Ceci conduit au deuxième résultat central, d'après lequel la variation de la perturbation de l'énergie cinétique du mouvement autour du centre de gravité dans und telle masse est égale à la perturbation, changée de signe, de la vitesse de dissipation d'énergie par les efforts de frottement.Ces deux résultats impliquent, selon l'auteur, un changement radical dans la manière de traiter le problème de l'origine de l'énergie des perturbations. En particulier ils montrent qu'il faut rejeter les modèles margulésiens ou margulésiens généralisés, selon lesquels toute perturbation est essentiellement un mécanisme qui emprunte son énergie cinétique à l'enthalpie de la masse.Le mouvement de base, produit directement par l'ensemble des actions extérieures thermodynamiques et mécaniques qui agissent sur le fluide, doit être considéré comme étant celui qui réalise à chaque instant, pour ses différentes propriétés, le minimum de variation temporelle. Ceci implique l'existence, en chaque point du fluide, d'une fonction de dissipation essentiellement positive, d'où résulte que la loi des efforts de frottement dans le mouvement de base est nécessairement une loi de Hooke isotrope. Sous l'influence des mêmes actions extérieures, le fluide prend cependant un mouvement différent du mouvement de base (en d'autres termes, il se superpose à celui-ci une perturbation) parce que la loi réelle des efforts de frottement n'est pas rigoureusement une loi de Hooke isotrope. La perturbation est donc, à chaque instant, la résultat de l'action, étendue à tout le passé du fluide, de la différence des deux lois des efforts de frottement.En négligeant cependant différentiellement, à un instant donné, la partie des efforts de frottement qui ne correspond pas à une loi de Hooke isotrope, on arrive facilement à une généralisation du théorème de Helmholtz sur la fonction de dissipation, et l'on montre que la condition nécessaire et suffisante pour qu'il existe une perturbation non nulle est que le mouvement de base soit rotationnel ou divergent.

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Summary The thermo-hydrodynamical equation for an arbitrary finite mass of the fluid is first of all deduced. This equation realizes the synthesis of the equations of motion, the equation of continuity, the equation expressing the first principle of thermodynamics and the equation of state. In its primary form, the thermo-hydrodynamical equation cannot be easily applied, for several reasons, to the investigation of the energy transformations in a given mass. However, by considering the separation of the motion in a basic motion and a perturbation, and applying the thermo-hydrodynamical equation to the same mass in the real and the basic motion (in other words, to a mass with the same displacements of its boundary surface in the real as in the basic motions), a much more simple (but still exact) form of this equation can be derived. This new form expresses the perturbation of the kinetic energy of the motion around the gravity centre of the mass as a function of the perturbation of its enthalpy (margulesian term) and the perturbation of the energy dissipation inside the mass by the frictional stresses. A first result follows from this equation, which states that the perturbation of the energy dissipation by the frictional stresses must necessarily and efficiently contribute, in some volumes of the fluid, to an increase of the kinetic energy of the perturbations.The enthalpy variation can be expressed as a function of the motion of the gravity centre of the mass. It can then be shown that the temporal variation of the enthalpy perturbation must vanish for any mass with no perturbation of the motion of its boundary surface. This property then leads to the second central result of the paper, which states that the temporal variation of the perturbation of the kinetic energy of the motion around the gravity centre of such a mass is due solely to the perturbation of the rate of energy dissipation by the frictional stresses.In the author's opinion, these results lead to a radical change of attitude towards the fundamental problem of the origin of the energy of the perturbations. They show, for instance, that any margulesian or generalized margulesian perturbation model, consisting essentially in a mechanism borrowing its kinetic energy from the enthalpy of the mass, should be rejected.The basic motion is the direct effect of the thermodynamical and mechanical external actions and must be considered as the motion which realizes, at any moment, a condition of minimum temporal variation for its properties. Consequently, an essentially positive dissipation function must exist at any point in the basic motion. The corresponding law for the frictional stresses is necessarily an isotropic Hooke's law. The real motion of the fluid, under the influence of the same external actions, differs from the basic motion because the real law of the frictional stresses is not strictly an isotropic Hooke's law. At any moment, the perturbation is the integrated result, for all the life history of the fluid, of the difference between the two laws of the frictional stresses.Neglecting however differentially, at a given moment, the part of the frictional stresses not corresponding to an isotropic Hooke's law, a generalization of Helmholtz theorem on the dissipation function can be derived, with the consequence that the necessary and sufficient condition for a non vanishing perturbation is a rotational or divergent basic motion.

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Communication à la 3ème Assemblée de la «Società Italiana di Geofisica e Meteorologia» (Gênes, 15–17 Avril 1955).  相似文献   

长江中下游大型湖泊水体固有光学特性:Ⅰ.吸收   总被引：1，自引：0，他引：1  

王长凤  段洪涛  马荣华  张玉超 《湖泊科学》2013,25(4):497-504

吸收系数是水体固有光学特性的重要组成部分,也是构建水色参数高精度遥感模型的基础,具有重要的研究意义.本文针对长江中下游三大淡水湖——鄱阳湖(2010 10、2011 08)、太湖(2008 10、2011 08)和巢湖(2009 10)进行5次野外实验,以International Ocean Colour Coordinating Group(IOCCG)2000年报告"Remote Sensing of Ocean Colour in Coastal,and Other Optically-Complex,Waters"为基础,对水体不同光学主导类型进行分类;并根据a_d(非色素颗粒物吸收)、a_ph(浮游植物色素吸收)、a_g(有色可溶性有机物吸收)等不同主导类型光谱曲线特征差异,引入a_d-g(主导类型a_d、a_g、a_d-a_g的合并类型)和a_ph-related(主导类型a_d-a_ph、a_d-a_ph-a_g的合并类型)类型,对主导类型进行归纳合并.结果显示:秋季,鄱阳湖、太湖、巢湖的主导类型较为单一,分别为a_d、a_d-a_g、a_d-a_ph-a_g;夏季,鄱阳湖和太湖同为两种类型共同主导,分别为a_d、a_d-a_g,a_d-a_ph-a_g、a_d-a_ph.总体来说,鄱阳湖夏、秋季和太湖秋季主导类型都属于a_d-g类型,而太湖夏季和巢湖秋季则属于a_ph-related类型.另外,分别针对Gons和Gitelson叶绿素a模型假设条件进行验证,发现不同湖泊水体及不同主导类型下其适用性程度不一致.  相似文献   

Seekarte und Landkarte     

H. Ermel 《Ocean Dynamics》1952,5(5-6):213-219

Zusammenfassung Die Landkarte im Sinne einer Karte, die das Festland darstellt, ist allgemein bekannt. Die Seekarte ist dagegen meistens nur einem begrenzten Personenkreis geläufig, der sich aus der seefahrenden und Küstenbevölkerung zusammensetzt. Obwohl die Seekarte gegenüber den Landkarten eine bewußte Selbständigkeit und Eigenart an den Tag legt, bestehen zwischen beiden Kartenarten doch viele Berührungspunkte, die in den Vermessungs- und Aufnahmemethoden, der Einteilung und Gliederung der Karten, den Kartensymbolen, den Projektionen, den Original-herstellungsverfahren und den Druckverfahren zum Ausdruck kommen. Darüber hinaus ist die Seekarte ebenso wie die bekannten internationalen allgemeingeographischen und geologischen Kartenunternehmen als Mittel zur Völkerverständigung anzusehen.

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Chart and map

Summary The map as a medium of representing the continents is known to almost all people while, on the contrary, only a limited number of persons, mostly the seafaring and maritime population is acquainted with the chart. Though a comparison between both types of representation shows that the chart maintains a pronounced independancy and a character of its own it has many features in common with the map, as will be seen from the methods of surveying, the classification of charts, the symbols, the projections, the drawing methods of originals and the printing procedure. Besides, like the well-known international enterprises in general geographical and geological cartography, the chart may be regarded as an aid in international understanding.

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Cartes marines et cartes géographiques

Résumé La carte géographique au sens d'une représentation de la terre ferme est bien connue de beaucoup de personnes tandis que la carte marine ne l'est que d'un petit nombre se composant surtout de marins et d'habitants du littoral. Une comparaison de la carte marine à la carte géographique montre que la carte marine a bien conservé son originalité et son indépendance prononcée malgré de nombreuses analogies entre les deux types de représentation comme par exemple la méthode du levé, la classification des cartes, les symboles, les projections ainsi que les procédés de dessin des cartes originales et les méthodes d'impression. De plus, semblable aux entreprises internationales en cartographie générale et géologique, la carte marine peut être considérée comme moyen d'entente internationale.

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Vortrag, gehalten auf dem 37. Geodätentag in Hamburg am 30. September 1952.  相似文献   

Forecasting the ionospheric f₀F₂ parameter one hour ahead using a support vector machine technique     

Chun Chen  Zhensen Wu  Shuji Sun  Panpan Ban  Zhonghua Ding  Zhengwen Xu   《Journal of Atmospheric and Solar》2010,72(18):1341-1347

This paper proposes a method for forecasting the ionospheric critical frequency, f₀F₂, 1 h in advance, using the support vector machine (SVM) approach. The inputs to the SVM network are the time of day, seasonal information, 2 month running mean sunspot number (R2), 3 day running mean of the 3 h planetary magnetic ap index, the solar zenith angle, the present value f₀F₂(t) and its first and second increments, the observation of f₀F₂ at t?23 h, the 30-day mean value at time, t, f_mF₂ (t) and the previous 30 day running mean of f₀F₂ at t?23 h f_mF₂(t?23). The output is the predicted f₀F₂ 1 h ahead. The network is trained to use the ionospheric sounding data at Haikou, Guangzhou, Chongqing, Lanzhou, Beijing, Changchun and Manzhouli stations at high and low solar activities. The performance of the SVM model was verified with observed data. It is shown that the predicted f₀F₂ has good agreement with the observed f₀F₂. The performance of the SVM model is superior to that of the autocorrelation and persistence models, and that it is comparable to that of the neural network model.  相似文献   

Effect of organic solvent type on the removal of nitrate ion using liquid membrane technique     

Şahset İrdemez  Nazmi Topçu  Yalçın Şevki Yıldız  Nuhi Demircioğlu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,21(2):175-181

In this study, the removal of nitrate ions from aqueous solutions with liquid membrane technique has been investigated for different organic solvent types in which solubilized tetradecyl trimethyl ammonium bromide (TDTMABr) as carrier. n-butyl alcohol, chloroform, and mixture of chloroform + n-hexane (n-hexane 85% + chloroform 15%) were used as organic solvent. Kinetic parameters (k _1d, k _2m, k _2a, t _max, R _m^max, J _m^max, J _a^max) were calculated from obtained data. time R _a values of mixture, butyl alcohol, and chloroform are 0.81, 0.78, and 0.55, respectively. Similarly R _d, R _m, and t _max values of the mixture equal to 0.14, 0.04, and 87.92 min, respectively. This behavior of the system shows the organic solvent type is an effective parameter on separation yield. It can be concluded that the mixture is the most effective organic solvent type among the investigated ones, because liquid membrane systems should be operated within the range of having the R _m, R _d, and t _max values are minimum while R _a values are maximum.  相似文献   

Les bilans énergétiques en météorologie dynamique     

Dr. Jacques Van Mieghem 《Pure and Applied Geophysics》1951,19(3-4):159-166

Résumé L'objet de cet article est d'établir les bilans énergétiques dans un référentiel quelconque, animé d'un mouvement variable d'un point à un autre et d'un instant à un autre. Le bilan de l'énergie mécanique se déduit, grâce au théorème des forces vives, des équations du mouvement de l'air par rapport au référentiel mobile. Le bilan qui exprime la conservation de l'énergie totale s'obtient en transposant, dans le référentiel mobile, l'expression du premier principe de la thermodynamique, énoncé dans le référentiel galiléen.

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Summary In this paper, energy equations of balance are established in any type of frame moving with an arbitrary, variable velocity with respect to space aud time. The equation of balance of mechanical energy can be deduced from the eqnations of motion of the air with respect to the moving frame. The equation of balance showing the conservation of total energy will be obtained by transposing in the moving frame, the expression of the first principle of thermodynamics given for the absolute frame.

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U, Th, K and Cs activity concentrations along the southern coast of the Caspian Sea, Iran     

Mohammad Reza Abdi  Smaeyl Hassanzadeh  Hamid Reza Raji 《Marine pollution bulletin》2009,58(5):658-662

The determination of activity concentrations of the radioactive elements ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs was performed on grab samples taken from a polluted environment. The samples were sliced into strata from 5 cm depth, dried and ground to sieved through a 170 mesh size prior to the analysis. Activity concentration was quantified using gamma spectroscopy. The results showed that the concentrations of activity in the sediment samples are 177 ± 12.4, 117 ± 11.5, 1085 ± 101.6 and 131 ± 4.8 Bq kg⁻¹ for ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs, respectively. In general, the distribution of activity concentrations along the southern coast of the Caspian Sea area exceeded international limits. The hazard index of the samples was 0.19-0.88, with an average of 0.49. The mean values of radium equivalent activity and dose rate are 176 Bq kg⁻¹ and 63 nGy h⁻¹, respectively.  相似文献   

Mesures de temperatures dans l'ice — Cap du Groenland     

Dr. J. -C. Heuberger 《Pure and Applied Geophysics》1956,34(1):71-73

Résumé Des mesures de températures ont été faites dans les Forages du Camp VI et de la Station Centrale, au cours de la Campagne de 1950, des « Expéditions Polaires Françaises 1948–1951 ». Ces mesures ne concordant pas avec celles effectuées par « L'Expédition Allemande au Groenland, A.Wegener, de 1930–31 », le ProfesseurKurt Wegener, dans un rapport intitulé « Température de l'Inlandsis du Groenland », commente les résultats, et, utilisant les résultats des deux Expéditions, établit la distribution de la température dans l'Inlandsis. — Le but de ce rapport est de justifier les mesures de 1950, de donner une limite d'utilisation de ces mesures, et d'expliquer les divergences entre les résultats des deux Expéditions.

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Summary In the drilled holes of Camp VI and «Station Centrale», temperature surveys were run during the 1950th expedition of «French Polar Expeditions 1948–1951» (MissionsPaul-Emile Victor). The measurements not being in agreement with those made by the «German Expedition to Greenland A.Wegener 1930–1931» Professor Dr.Kurt Wegener, in a report published in this revue (Die Temperatur in Grönländischen Inlandeis), comments the results and, using the results of both expeditions, gives the temperature distribution in the Greenland Ice-Cap. — The purpose of this report is to justify the 1950th surveys, to state the readings accuracy and to find out the causes of the divergences between the results of both expeditions.

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Metal concentrations in sediments from tourist beaches of Miri City,Sarawak, Malaysia (Borneo Island)     

R. Nagarajan  M.P. Jonathan  Priyadarsi D. Roy  L. Wai-Hwa  M.V. Prasanna  S.K. Sarkar  M. Navarrete-López 《Marine pollution bulletin》2013

Forty-three sediment samples were collected from the beaches of Miri City, Sarawak, Malaysia to identify the enrichment of partially leached trace metals (PLTMs) from six different tourist beaches. The samples were analyzed for PLTMs Fe, Mn, Cr, Co, Cu, Ni, Pb, Sr and Zn. The concentration pattern suggest that the southern side of the study area is enriched with Fe (1821–6097 μg g⁻¹), Mn (11.57–90.22 μg g⁻¹), Cr (51.50–311 μg g⁻¹), Ni (18–51 μg g⁻¹), Pb (8.81–84.05 μg g⁻¹), Sr (25.95–140.49 μg g⁻¹) and Zn (12.46–35.04 μg g⁻¹). Compared to the eco-toxicological values, Cr > Effects range low (ERL), Lowest effect level (LEL), Severe effect level (SEL); Cu > Unpolluted sediments, ERL, LEL; Pb > Unpolluted sediments and Ni > ERL and LEL. Comparative results with other regions indicate that Co, Cr, Cu, Ni and Zn are higher, indicating an external input rather than natural process.  相似文献   

Untersuchungen über den Wärmeumsatz an der Meeresoberfläche und die Meeresströmungen im Indischen Ozean     

Dr. Fritz H. W. Albrecht 《Pure and Applied Geophysics》1958,39(1):194-215

Zusammenfassung Der Küstenverlauf des Indischen Ozeans legt den Gedanken nahe, daß dieser Ozean in den Gebieten nördlich des 35. Parallelkreises südlicher Breite gegen die anderen Ozeane fast abgeschlossen ist. Denn die Durchlässe zwischen den Sunda Inseln, Neu Guinea und Australien sind vergleichsweise schmal gegenüber der Gesamtlänge der östlichen Küsten dieses Ozeans. Das Integral des Wärmeumsatzes, genommen über solch ein abgeschlossenes Meeresgebiet, müßte über das ganze Jahr Null sein, weil die Temperatur des Ozeans über längere Zeiten ungeändert bleibt. Untersuchungen, die in dieser Richtung im Jahre 1951 ausgeführt wurden, zeigten, daß diese Bedingung nicht erfüllt war. Der Ozean verlor Wärme.Die Beobachtungen in dem neuen Australischen Strahlungsnetz ließen erkennen, daß diese früheren Berechnungen eineÅngströmsche Formel für die Globalstrahlung benutzten, die zu kleine Werte gab. Die Berechnungen von Karten des Wärmeumsatzes mit einer korrigierten Formel zeigten Gleichheit von Wärmegewinn und Verlust für den ganzen Indischen Ozean. Aber es bestehen große Differenzen in den jährlichen Mitteln des Wärmeumsatzes in den verschiedenen Teilen dieses Ozeans. Besonders in seinem Mittelteil besteht ein großes Gebiet mit Wärmeverlust östlich von Madagaskar, während der Ozean im Norden und Süden von diesem Verlustgebiet Wärme aufnimmt. Der Wärmetransport zu dem Verlustgebiet des Wärmeumsatzes im Mittelteil des Ozeans ist nur möglich durch die Meereströmungen und zwar sowohlin der Oberfläche als auchunter derselben.In einem kurzen Abschnitt wurde der jährliche Gang des mittleren Wärmeumsatzes und der mittleren Oberflächentemperatur, genommen über den ganzen Indischen Ozean, behandelt. Es wurde eine Phasendifferenz zwischen beiden Elementen von zwei Monaten festgestellt und eine mittlere Stärke der vom Wärmeumsatz beeinflußten Oberflächenschicht von 123 m.Zur Untersuchung der Rolle der Meeresströmungen mit Bezug auf den Wärmetransport wurden zehn Bahnen von Körpern gezeichnet, die als mit den Meeresströmungen driftend angenommen wurden. Es wurde dann die Annahme gemacht, daß diese Driftwege die Bahnen der an der Oberfläche bewegten Wassermassen selbst darstellen. Der Wärmeumsatz und die Oberflächentemperaturen zeigen in den nördlichen und südlichen Teilen des Ozeans einen kleinen Wärmegewinn, aber für die Wege durch das Wärmeverlustgebiet eine beträchtliche Wärmeabgabe.Daraus mußte geschlossen werden, daß die ursprüngliche Annahme, der Indische Ozean bilde ein in sich abgeschlossenes System des Wärmeumsatzes, aufgegeben werden muß. In dem ganzen nördlichen Sommer wird der Ozean von einem Meeresstrom durchflossen, der durch die Öffnungen an seinen Ostküsten in der Äquatorialzone kommt, nach Westen fließt und in den Agulhas-Strom entlang Südafrika einmündet.Betrachtet man den Beitrag der Zirkulationen unter der Oberfläche zu dem Ausgleich zwischen den Gebieten positiven und negativen Wärmeumsatzes, so muß die Tatsache betont werden, daß in den Tiefen von 200 und 400 m unter den Gebieten des stärksten Wärmeverlustes an der Oberfläche sowohl im Indischen als auch im Stillen Ozean Gebiete von relativen Höchsttemperaturen liegen.

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Summary The shape of the coasts of the Indian Ocean suggests that this ocean is, in its area north of 35° S almost separated from the other oceans, because the openings between the Sunda Islands, New Guinea, and Australia are comparatively narrow with reference to the total length of the eastern coasts of this ocean. The integral of the heat exchange on the surface of the ocean extended over such a closed ocean region should be zero for the whole year, because the temperature of the ocean is unchanged for long periods. Investigations carried out in this direction in 1951 showed that this condition was not satisfied: The ocean displays a loss in heat.The observations of the new Australian radiation network showed, used for the relevant calculations, thatÅngströms formula of global radiation gave too small values. The new calculations of charts of the heat exchange with a corrected formula showed equality of heat gain and loss for the whole Indian Ocean. But large differences in the yearly means of heat balance exist in different parts of this ocean. In particular, a large region of heat loss is present in the central part of the ocean east of Madagascar, while the ocean in the North and the South of this region gains heat. The transport of heat to the region of heat loss in the central part of the Indian Ocean is only possible by ocean currents, both, on the surface und under the surface.In a section of this paper the annual variation of the mean heat exchange and the mean surface temperature is treated for the whole Indian Ocean. A phase difference of two months between both elements and a mean thickness of 123 m for the surface layer influenced by the heat exchange were found.For investigations on the rôle of ocean currents with regard to the transport of heat ten trajectories of masses drifting with the currents were drawn on a chart of the Indian Ocean, assuming that these trajectories represent also the paths of water masses themselves. The heat exchanges and the temperatures along these paths show for the paths in the northern and southern parts of the ocean a small gain of heat but, for the ways through the above mentioned region of heat loss a considerable loss of heat.Therefore, it can be concluded that the previous assumption of the Indian Ocean, being a system with an own heat balance, must be abandoned. In the whole northern summer the ocean is penetrated by a current of water coming through the openings in the equatorial zone, flowing towards West and flowing into the Agulhas current along South Africa.Considering the contribution of the circulations under surface to the compensation between the regions of positive and negative heat exchange, it must be emphasised that regions of maximum temperatures lie under the regions of the largest heat loss in depths of 200 and 400 m in both, the Indian and the Pacific Oceans.

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Balance of energies in the development of sea waves,semi-empirical evaluation     

B. V. Korvin-Kroukovsky 《Ocean Dynamics》1965,18(4):145-160

Summary As sea waves develop with increasing fetch, a balance is continuously maintained among the enegy increase in waves, the rate of energy received from the wind, and the rate of the energy dissipated in water. In making a semi-empirical analysis of this problem, the first is evaluated by B. W. Wilson's Formula IV, the second by aerodynamic and meteorological methods and data, and third by matching certain dimensional considerations to the difference of the first two. In the consequent synthesis the rate of the wave energy growth is evaluated as the rate of the wind energy input less the rate of energy dissipation. The growth of the wave energy with increase of the fetch is finally evaluated by numerical integration of energy equations. The increase of the energy is resolved into increases of wave celerity and height by simultaneous solution of energy and momentum equations. The form of energy equations, and the experience with their integration provide explicit indication of many factors affecting the wave growth, in addition to the, commonly used, wind speed and fetch.

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Der Energiehaushalt bei der Entwicklung von Meereswellen, halb-empirische Auswertung

Zusammenfassung Da sich die Meereswellen mit zunehmendem Windweg entwickeln, ist ständig ein Gleichgewicht vorhanden zwischen der Energiezunahme der Wellen, dem Anteil der Energie, die sie vom Wind erhalten und dem Energieanteil, der im Wasser vernichtet wird. Bei einer halbempirischen Analyse dieses Problems wird ersteres nach der Formel IV von B. W. Wilson untersucht, zweites an Hand von aerodynamischen und meteorologischen Methoden und Daten und letzteres durch gewisse Dimensionsbetrachtungen über die Differenz der beiden ersten. In der anschließenden Synthese wird die Zuwachsrate der Wellenergie berechnet aus dem Verhältnis der Windenergie, die ihr zugeführt wird, abzüglich der Energievernichtung. Die Wellenenergiezunahme ist mit zunchmendem Windweg schließlich durch numerische Integration von Energiegleichungen berechenbar. Die Energiezunahme wird zerlegt in die Zunahme der Wellengeschwindigkeit und-höhe bei gleichzeitiger Lösung von Energie- und Impulsgleichungen. Die Form der Energiegleichungen und die Erfahrungen mit ihrer Integration geben einen klaren Hinweis auf die vielen Faktoren, die das Wachsen der Wellen verursachen, zusätzlich zu Windgeschwindigkeit und Windweg, die normalerweise nur berücksichtigt werden.

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Bilan d'énergie dans la formation des vagues; évaluation semi-empirique

Résumé Tandis que les vagues se développent à mesure que s'accroît le fetch, un équilibre est continuellement maintenu entre l'accroissement d'énergie des vagues, la part d'énergie fournie par le vent et la part d'énergie dissipée dans l'eau. Pour faire une analyse semi-empirique du problème, la première est évaluée au moyen de la formule IV de B. W. Wilson, la seconde par des méthodes et des données aérodynamiques et météorologiques et la troisième en adaptant certaines considérations d'ordre dimensionnel à la différence entre les deux premières. Dans la synthèse qui en résulte, le taux d'accroissement de l'énergie des vagues est considéré comme étant la différence entre la part de l'énergie fournie par le vent et celle de l'énergie dissipée. L'accroissement de l'énergie des vagues à mesure qu'augmente le fetch est obtenu finalement par intégration numérique des équations d'énergie. Cet accroissement d'énergie se traduit en accroissements de la célérité des vagues et de leur hauteur obtenus en résolvant simultanément les équations d'énergie et des moments cinétiques. La forme des équations d'énergie et l'expérience avec leur intégration fournissent des indications explicites sur les nombreux facteurs qui interviennent dans la croissance des vagues, en plus de la vitesse du vent et du fetch habituellement utilisés.

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Seasonal variations in pCO₂ and its controlling factors in surface seawater of the northern East China Sea   总被引：2，自引：0，他引：2  

JeongHee Shim  Dongseon Kim  Young Chul Kang  Jae Hak Lee  Sung-Tae Jang  Cheol-Ho Kim 《Continental Shelf Research》2007,27(20):2623-2636

Surface partial pressure of CO₂ (pCO₂), temperature, salinity, nutrients, and chlorophyll a were measured in the East China Sea (ECS; 31°30′–34°00′N to 124°00′–127°30′E) in August 2003 (summer), May 2004 (spring), October 2004 (early fall), and November 2005 (fall). The warm and saline Tsushima Warm Current was observed in the eastern part of the survey area during four cruises, and relatively low salinity waters due to outflow from the Changjiang (Yangtze River) were observed over the western part of the survey area. Surface pCO₂ ranged from 236 to 445 μatm in spring and summer, and from 326 to 517 μatm in fall. Large pCO₂ (values >400 μatm) occurred in the western part of the study area in spring and fall, and in the eastern part in summer. A positive linear correlation existed between surface pCO₂ and temperature in the eastern part of the study area, where the Tsushima Warm Current dominates; this correlation suggests that temperature is the major factor controlling surface pCO₂ distribution in that area. In the western part of the study area, however, the main controlling factor is different and seasonally complex. There is large transport in this region of Changjiang Diluted Water in summer, causing low salinity and low pCO₂ values. The relationship between surface pCO₂ and water stability suggests that the amount of mixing and/or upwelling of CO₂-rich water might be the important process controlling surface pCO₂ levels during spring and fall in this shallow region. Sea–air CO₂ flux, based on the application of a Wanninkhof [1992. Relationship between wind speed and gas exchange over the ocean. Journal of Geophysical Research 97, 7373–7382] formula for gas transfer velocity and a set of monthly averaged satellite wind data, were −5.04±1.59, −2.52±1.81, 1.71±2.87, and 0.39±0.18 mmol m⁻² d⁻¹ in spring, summer, early fall, and fall, respectively, in the northern ECS. The ocean in this study area is therefore a carbon sink in spring and summer, but a weak source or in equilibrium with the atmosphere in fall. If the winter flux value is assumed to have been the mean of autumnal and vernal values, then the northern ECS absorbs about 0.013 Pg C annually. That result suggests that the northern ECS is a net sink for atmospheric CO₂, a result consistent with previous studies.  相似文献   

Melt segregation inside a partially molten zone: Theory,numerical models and implications     

Ya. M. Khazan  O. V. Aryasova 《Izvestiya Physics of the Solid Earth》2011,47(5):425-439

For the problem of matrix compaction and melt segregation a general mush continuity equation is derived, which explicitly expresses the coupling between the melt percolation and the inelastic matrix deformation and closes the governing equation set. Besides, a general equation is obtained, which describes the change in the volume of pore space due to all the possible reasons (inelastic matrix deformation, the phase transitions, and the advection of porosity by the matrix flow). The features of the isothermal melt segregation inside a partially molten zone are demonstrated using one-dimensional (1D) numerical solutions. It follows from the solutions that the pattern and the characteristic time of the melt segregation inside a partially molten zone of thickness L are controlled by the segregation parameter γ _c = (L/δ _c )², where the compaction length δ _c = k(φ₀)η/(φ₀μ) depends on the permeability, k, the value of characteristic porosity, φ₀, and the viscosities of the matrix, η, and melt, μ. The solutions demonstrate that at any value of γ _c , layers that are highly enriched in melt compared to the maximum initial porosity are formed in the upper part of the zone. At the same time, the evolution of the system and the segregation time differ considerably in the limits of γ _c ≪ γ* and γ _c ≫ γ*, where γ* depends on the boundary and initial conditions of the problem, and γ* is about 80 for the problem of melt segregation inside a partially molten zone with the maximum in the initial melt distribution located in the middle of the zone. At γ _c ≪ γ*, which corresponds to the segregation of low-viscosity ultrabasic melts (kimberlites, carbonatites), all the melt accumulates to the roof of the zone, and the segregation time does not depend on the matrix permeability and melt viscosity and decreases with an increase in the thickness of the zone as L ⁻¹. The latter can be the reason for the formation of clusters of the same age and same composition eruptions characteristic of the kimberlite provinces. In the opposite limiting case, γ _c ≫ γ*, the segregation time does not depend on the matrix viscosity and scales as L with a wave sequence forming in the upper part of the zone, which, probably, elucidates the origin of the rhythmical layering of the large tholeiitic basalt plutons.  相似文献