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1.
《Marine Chemistry》2001,73(3-4):291-303
Oxygen and phosphate measurements from two sections across the Norwegian Atlantic Current, the Gimsøy-NW section from 67.5°N 9°E to 71.5°N 1°E and the Bjørnøya-W section along 74.5°N from 7 to 15°E, are used to estimate oxygen fluxes in the surface layer and between the atmosphere and the ocean. Vertical entrainment velocities of 0.9 m day−1 for the winter season and 0.1 m day−1 for the summer season are found and applied to the upper 300 m. The resulting oxygen fluxes to the surface layer driven by this vertical mixing are 0.58±0.05 and 0.27±0.02 mol O2 m−2 year−1 at the Gimsøy-NW and Bjørnøya-W sections, respectively. Oxygen fluxes to the surface layer due to phytoplankton production are 2.6 and 3.4 mol O2 m−2 year−1, which represent the net community production at the two sections. Estimated uncertainties in these numbers are ±15%. The surface water is a sink for atmospheric oxygen during fall and winter and a source during the productive season for both sections. On an annual basis there is a net uptake of oxygen from the atmosphere, 3.4±0.4 mol O2 m−2 year−1 at the Gimsøy-NW section and 4.9±0.5 mol O2 m−2 year−1 at the Bjørnøya-W. A decrease in temperature of 1°C to 1.5°C seen between the Gimsøy-NW section and the Bjørnøya-W section is the main reason for the increased atmospheric flux of oxygen at the latter section. An oxygen budget made for the area bounded by the two sections gives a net advective flux of oxygen out of the area of approximately 10 mol O2 m−2 year−1. The increased concentration of oxygen corresponding to the decrease in surface layer temperatures going northwards in the Norwegian Atlantic Current is mainly attributed to the air–sea oxygen exchange and phytoplankton production in this area.  相似文献   

2.
由于缺乏长期观测资料,前人对山东半岛邻近海域海水溶解氧的时间变化和空间分布特征的研究较少。本文基于威海刘公岛海洋牧场于2016年7月20日至2017年3月14日期间,利用生态环境实时在线观测系统获得的底层海水的温度、盐度、水深、溶解氧数据,分析了该牧场海水溶解氧浓度的时间变化特征及其影响因素,并探讨了低氧灾害发生的可能性。结果表明在观测期间,该牧场海水溶解氧浓度以季节变化为主,冬季最大、夏季最小,其中2月份平均值最高,约为10.86mg/L,8月份平均值最低,约为5.91mg/L。同时海水溶解氧浓度也存在显著的小时变化和日变化,且变化幅度于8月份最大、3月份最小。影响海水溶解氧浓度变化的主要因素是海水温度,溶解氧浓度随着温度的季节性变化而变化。夏季,水体分层会使溶解氧浓度发生大幅度的降低,大风过程对于溶解氧浓度也有一定的影响,通过打破夏季的季节性温跃层使水体发生垂向混合从而为海底提供氧气,但大风过程之后的几天会出现溶解氧浓度降低的现象。本次研究发现刘公岛海洋牧场在观测期间不存在低氧现象。  相似文献   

3.
-During the multi-disciplinary investigations on the waters of Nansa Islands for three cruises respectively in 1985. 1986. 1987. it is found that the dissolved oxygen maximum (DOmax) in its vertical distribution usually exists between 20m and 75m deep. The deep position of O2 maximum is near the thermocline below and above the deep chlorophyll maximum, as well as above the light-beam attenuation coefficient maximum. In the parts of O2 maximum occurring, the minimum of CO2 partial pressure and the maximum of pH value are also found at the same depth. It is still difficult to explain the features exactly by using the published research results about the oxygen maximum in its vertical distribution on the waters of middle and high latitude.In the present paper, the dissolved oxygen maximum in its vertical distribution on the waters of low latitude is described. It is made by an internal wave which holds eddy mixture. The feature appears to arise from the biological photosynthesis with stratification, from t  相似文献   

4.
Data on the diffusion coefficientK zand the concentration of H2S in the Black Sea are used to compute the depth distribution of the vertical flux, and the intensity of the H2S sources and sinks. On average, the total production of H2S in the Black Sea reaches 37×106 t/year. The main bulk of H2S is produced not at the bottom, but in the layer of 450–1300 m. Destruction of H2S prevails above the 400 m layer. Dissolved oxygen penetrating the H2S zone can oxidize only half of the hydrogen sulphide produced in the sea.Translated by Mikhail M. Trufanov.  相似文献   

5.
We have observed the temporal variation of oxygen deficient water with short time scale (less than a few days) in the central area of Ohmura Bay, Kyushu, Japan, in summer, 1995 and 1996. The vertical profiles of temperature were similar to those of dissolved oxygen. We noticed a linear relation between temperature and dissolved oxygen in the bottom layer, and applied the T-DO relation to estimate the net oxygen consumption rate, rather than direct evaluation of the advection and diffusion. Oxygen consumption rate just above the bottom was estimated to be about 0.21 g O2 m–3day–1 in July 1995, and about 0.28 g O2 m–3day–1 in August 1996. The net oxygen consumption rate estimated for the bottom layer below the second thermocline was about 0.61 g O2 m–3day–1 with variability from 0.55 to 0.66 g O2 m–3day–1 during July 25 to 29, 1995. This is was about 0.64 g O2 m–3day–1 with variability from 0.18 to 1.4 g O2 m–3day–1 during August 22 to 30, 1996. The net oxygen consumption rates are about half of those measured with a closed system in the Seto Inland Sea.  相似文献   

6.
基于2020年夏季的大面航次观测数据,分析了烟台—威海北部海洋牧场及邻近海域海水溶解氧浓度垂向分布最小值（氧最小值层）的空间分布特征,并探讨了影响因素。从6月至8月,海水溶解氧浓度不断减小,垂向结构亦存在显著变化。海水溶解氧浓度垂向分布的最小值主要集中于7月的近岸海域,最小值大致从外海向近岸方向减小,其距离海底高度及与底层溶解氧浓度之差的绝对值均于双岛湾邻近海域为最大。海水溶解氧浓度垂向分布的最小值位于最强密度层结以下。但是海水溶解氧浓度垂向分布最小值的强度向北减小,而密度层结向北增大,两者的空间分布基本相反,说明密度层结抑制垂向湍流扩散可极大减少深层海水溶解氧的来源,是海水溶解氧浓度垂向分布最小值形成的必要条件,但不是主导因素。在海水溶解氧浓度垂向分布的最小值层,表观耗氧量存在垂向分布的最大值,大部分站点的pH存在垂向分布的最小值,说明局地增强、持续的生物地球化学耗氧是控制海水溶解氧浓度垂向分布最小值形成和空间分布的一个重要过程。研究结果表明氧最小值层是夏季烟台—威海北部近岸海水溶解氧垂向结构的典型特征之一。  相似文献   

7.
Regularities of oxygen and hydrogen sulfide are examined, using the method of spatial isopycnic analysis. The contribution that ventilation of winter-time surface waters over the domes of cyclonic gyres makes to the transfer of O2 towards the upper boundary of the constant pycnocline and to the oxicline layer is demonstrated. The paper provides spatial scales of this phenomenon and indicates the areas where the upper boundary of the anoxic layer in the Black Sea, relative to the conventional density, is located much higher compared with the rest of the sea. The suboxic zone is shown to be a specific feature of the O2/H2S distribution in the Black Sea waters, typical, at least, of the northern part of the basin. Analysis of the suboxic spatial variability in the vertical has been conducted. Translated by Vladimir A. Puchkin.  相似文献   

8.
Measurements of dissolved gases (O2, N2O), nutrients (NO3−, NO2−, PO43−), and oceanographic variables were performed off northern Chile (∼21°S) between March 2000 and July 2004, in order to characterize the existing oxygen minimum zone (OMZ) and identify processes involved in N2O cycling. Both N2O and NO3− displayed sharp, shallow peaks with concentrations of up to 124 nM (1370% saturation) and 26 μM, respectively, in association with a strong oxycline that impinges on the euphotic zone. NO2− accumulation below the oxycline's base reached up to 9 μM. The vertical distribution of physical and chemical parameters and the existing relationships between apparent oxygen utilization (AOU), apparent N2O production (ΔN2O), and NO3− revealed three main layers within the upper OMZ. The first layer, or the upper part of the oxycline, is located between the base of the mixed layer and the mid-point of the oxycline (around σt=25.5 kg m−3). There the O2 declines from ∼250 to ∼50 μM, and strong (but opposing) O2 and NO3− gradients and their associated AOU–ΔN2O and AOU–NO3− relationships indicate that nitrification produces N2O and NO3− in the presence of light. The second layer, or lower part of the oxycline, represents the upper OMZ boundary and is located between the middle and the base of the oxycline (25.9<σt<26.1 kg m−3). In this layer NO3− reduction begins at O2 levels ranging from ∼50 to ∼11 μM and accumulation of 41–68% of the ΔN2O pool occurs. The accumulation of N2O (but not of NO2− or NH4+) and the observed AOU–ΔN2O and AOU–NO3− relationships (which are opposite to those of the overlying first layer) suggest that a coupling between nitrification and NO3− reduction is involved in N2O cycling in this second layer. The third layer is the OMZ core, where the O2 concentration remains constant (O2<11 μM). It coincides with σt>26.2 kg m−3, which is typical of Equatorial Subsurface Water (ESSW). In this layer, N2O and NO3− continue to decrease, but a large NO2− accumulation is observed. Considering all the data, a biogeochemical model for the upper OMZ off northern of Chile is proposed, in which nitrification and denitrification differentially mediate N2O cycling in each layer.  相似文献   

9.
For the first time in situ, deep penetrating O2 profiles were measured in abyssal sediments in the western South Atlantic. Construction of deep penetrating O2 optodes and adaptation to a benthic profiling lander are described. The opto-chemical oxygen sensors allow measurements to a depth of 55 cm in marine sediments. A vertical resolution of 0.5 cm was used to determine the O2 dynamics in those oligotrophic deep sea sediments; the oxygen concentration across the sediment water interface was measured with a resolution of 100 μm. Oxygen penetration depth (OPD), diffusive oxygen uptake (DOU) and oxygen consumption rates were determined at four stations north of the Amazon fan and one at the Mid-Atlantic Ridge. Diffusive oxygen uptake rates ranged from 0.1 to 0.9 mmol m−2 d−1; the oxygen penetration depth ranged from 8 to 26 cm. Carbon consumption rates calculated from the diffusive oxygen uptake rates were in the range of 0.3–3.0 g C m−2 a−1. Comparison between in situ and laboratory DOU and OPD measurements confirmed previous findings that core recovery and warming have strong effects on the oxygen dynamics in deep sea sediments. Laboratory measurements yielded a decrease of 50–75% in OPD and consequently an increase in DOU by 1.5 and 18-times. Deep penetrating oxygen optodes provide a new tool to accurately determine oxygen dynamics (and thereby calculate carbon mineralization rates) in oligotrophic sediments. However, oxygen optodes as used in this study do not resolve the diffusive boundary layer (DBL). The data show that deep penetrating O2 optodes in combination with high-resolution O2 microelectrodes give a complete picture of the oxygen dynamics, including the DBL, in deep sea sediments.  相似文献   

10.
Net community biological production in the euphotic zone of the ocean fuels organic matter and oxygen export from the upper ocean, which has a large influence on the atmospheric pressure of carbon dioxide and is the driving force for metabolite distributions in the sea. We determine the net annual biological oxygen production in the mixed layer of the northeast subarctic Pacific Ocean from in situ O2 and N2 measurements. Temperature, salinity, total gas pressure and O2 were measured every 3 h for 9 months in 2007 at about 3 m depth on a surface mooring at Station P (50°N, 145°W). The concentration of nitrogen gas, N2, determined from separate total gas pressure and pO2 measurements, was used as an inert tracer of the physical processes that induce gas departure from thermodynamic equilibrium with the atmosphere. We use a simple model of the ocean’s mixed layer along with the nitrogen concentration to constrain the importance of bubbles, gas exchange and horizontal advection, which are then used in the oxygen mass balance to derive net biological oxygen production. The mixed-layer oxygen mass balance is dominated by exchange with the atmosphere, and we determine a mean summertime oxygen production of 24 mmol O2 m?2 d?1. The annual pattern in the difference between the supersaturation of oxygen and nitrogen in the surface waters reveals very little net oxygen production during the winter at this location. The calculated annual net community production (NCP) of carbon from this new method, 2.5 mol m?2 yr?1, agrees to within its error of about×40% with previous determinations at this location from oxygen mass balance, NO3? draw down and 234Th measurements. This value is either indistinguishable from or lower than annual NCP measurements in the subtropical North Pacific, indicating that there is no experimental evidence for differences in annual NCP between the subarctic and subtropical North Pacific Ocean.  相似文献   

11.
本研究首次探究了西太平洋雅浦海沟北段从表层到超深渊海水中甲烷（CH4）及二甲基硫（DMS）的前体物质二甲基巯基丙酸内盐（DMSP）的浓度变化情况。结果表明:雅浦海沟海水甲烷浓度变化范围为1.49~3.87 nmol/L。其上层海水甲烷平均浓度最高,有明显的次表层极大现象。雅浦海沟氧最小层海水的甲烷平均浓度最低;在500~1 000 m中层水中甲烷浓度有一定程度的增大,1 000 m以下至底层甲烷浓度继续升高。研究海区溶解态DMSP（DMSPd）和总DMSP（DMSPt）平均浓度的垂直变化随深度呈先增大后减小趋势,颗粒态DMSP（DMSPp）的平均浓度随深度呈波动式变化,在中层达到最大。雅浦海沟CH4和DMSP浓度垂直变化受浮游生物、微生物、光照、温度、压力、大洋环流等的复杂影响。在真光层海水中,CH4浓度与DMSPd、DMSPp和DMSPt浓度表现为负相关关系,在200 m至底层海水中,CH4浓度与DMSPd、DMSPp和DMSPt浓度表现为正相关关系,显示光照条件是造成雅浦海沟不同深度海水CH4和DMSP浓度相关性差异的关键因素。  相似文献   

12.
南海北部陆架陆坡区海流观测研究   总被引：3，自引：0，他引：3  
针对2006-2009年期间,南海北部陆架陆坡区3个站ADCP海流连续观测资料,采用功率谱分析、潮流调和分析方法,重点分析了陆架陆坡区100 m,200 m和1 200 m水深海域海流的垂向结构,探讨了环流的季节变化和空间分布特征,特别讨论了南海暖流和北陆坡流的时空变化特征。结果表明,陆架陆坡区潮流类型属于不规则日潮,深水站点中层表现为正规全日潮类型,垂向为"三层结构",甚至更加复杂。O1,K1,M2,S2等分潮总体上为顺时针旋转,在深水站点,基本表现为西北－东南走向的往复流形态。从能量角度看,表层和底层海流中,潮流所占份额较大,分别占30%~40%和40%~50%,中层较小,约为20%。对东沙群岛西南陆架陆坡区环流,观测计算结果证实了西向强流的存在,且垂向结构具有显著的季节变化,在200 m水深处没有明显的南海暖流,只是10~30 m以上层次存在逆风海流。海南岛以东海域连续15个月表层环流的结果表明,冬季明显受到南海暖流的影响,存在东北向的逆风海流,夏秋季的环流表现为西南向,流速较强,夏季也存在逆风情况,造成上述情形的原因可能是该地南海暖流的流轴具有季节性变化——冬季偏南,夏季偏北。  相似文献   

13.
This paper focuses on the impact of periodic internal waves on the oxygen/hydrogen sulphide co-existence zone in the open Black Sea. The numerical model is based on a set of transport/diffusion equations governing the evolution of oxygen/hydrogen sulphide concentrations and considering the reaction between them. The wave velocity field is determined by solving a spectrum problem for preinertial period internal waves, using the characteristic vertical density profile for summertime. Via analysis of the model data, the influence of wave characteristics on the parameters of the O2/H2S co-existence zone has been assessed.Translated by Vladimir A. Puchkin.  相似文献   

14.
《Marine Chemistry》2002,79(1):27-36
Preformed Cd and PO4 were investigated in the northwestern Pacific (Station CM05) and the Okhotsk Sea (Station CM06), and the relationship between the two elements was examined. At CM05, from the apparent oxygen utilization (AOU)–Cd and PO4 plot, the different molecular ratios of consumed O2 to regenerated Cd and PO4 were calculated to be 254,000 (Cd) and 96 (PO4) for the shallow layer (30–99 m) and 613,000 (Cd) and 170 (PO4) for the deep layer (below the oxygen minimum layer), which suggested the preferential remineralization of Cd and PO4 in the shallow layer. At CM06, regeneration ratios of O2/Cd, PO4 were obtained only in the shallow layer (29–124 m) as 227,000 (Cd) and 75 (PO4). The calculated preformed Cd and PO4 concentrations in the shallow layer were 0.59 nM of Cd and 1.6 μM of PO4 at CM05 and 0.35 nM of Cd and 0.95 μM of PO4 at CM06. These concentrations were much higher than those (close to 0) in the low-latitude area, which was attributable to the supply of these constituents from deep water by the strong winter convection. In the deep layer, at CM05, preformed concentrations were 0.64 nM of Cd and 1.4 μM of PO4. Preformed PO4 generally agreed with previously reported values in the Pacific, which suggested that the concentrations of the initial PO4 in the deep water were preserved as preformed through the movement to the northwestern Pacific. On the other hand, obtained preformed Cd in the northwestern Pacific deep water showed a somewhat higher value than that in the southwest Pacific. The possibility of the terrestrial input and remineralization of Cd by CaCO3 dissolution during the northward movement was considered. A plot of Cd and PO4 showed a linear relationship with slopes of 0.34 and 0.40 (nM/μM) at CM05 and CM06, respectively, which generally agreed with the reported values in the North Pacific.  相似文献   

15.
A one-dimensional ionic-photochemical model of the gaseous composition of the atmosphere that describes the formation of the D layer of the ionosphere is presented. Based on this model, the vertical profiles of the concentration of electrons and ions in the D layer of the ionosphere were calculated, as were the vertical distributions of minor gaseous constituents in the atmosphere up to a height of 86 km for undisturbed conditions and after a powerful solar proton events (SPE) at the end of October 2003. The calculations showed that SPEs significantly increase NOx in the mesosphere of polar latitudes. In the lower mesosphere of polar caps, the NOx mixing ratio increases by 20–50 ppb; in the upper mesosphere it increases by 100 ppb and more. High NOx levels in zones of their formation can be retained for several weeks, producing a long-term but comparatively small ozone decrease in the lower mesosphere. The main ozone decrease is caused by a short-term HOx increase after SPEs and is also of a short-term character in the conditions of the illuminated mesosphere. After the SPE in October 2003, model calculations yield an ozone concentration decrease by 40% in the middle and upper mesosphere at 75 ° S and by 70% at the same heights at 70 ° N. The results of modeling NOx and O3 changes after the SPE in October 2003 agree well with the data of satellite measurements. The changes in minor gases of the mesosphere after the SPE obtained in the model with parameterized sources of HOx and NOx are compared with their changes obtained in the complete ionic-photochemical model. The changes in HOx, NOx, and O3 coincide rather well, whereas the changes in ClO noticeably differ, especially in the lower mesosphere. Thus, at a height of about 60 km, the parameterized photochemical model underestimated twofold the ClO formation after the SPE.  相似文献   

16.
The relationship between particulate organic carbon (POC) concentrations measured in modern sediment and fluxes of exported POC to the sediment surface needs to be understood in order to use POC content as a proxy of paleo-environmental conditions. The objective of our study was to compare POC concentrations, POC mineralization rates calculated from O2 consumption and POC burial rates. Benthic O2 distributions were determined in 58 fine-grained sediment cores collected at different periods at 14 stations in the southeastern part of the Bay of Biscay with depths ranging from 140 to 2800 m. Depth-dependent volume-specific oxygen consumption rates were used to assess rates of aerobic oxidation of organic matter (OM), assuming that O2 consumption solely was related to heterotrophic activity at the sediment–water interface. Heterogeneity of benthic O2 fluxes denoted changes in time and space of fresh organic material sedimentation. The most labile fraction of exported POC engendered a steep decrease in concentration in the upper 5 mm of vertical O2 profiles. The rupture in the gradient of O2 microprofile may be related to the bioturbation-induced mixing depth of fast-decaying carbon. Average diffusive O2 fluxes showed that this fast-decaying OM flux was much higher than buried POC, although diffusive O2 fluxes underestimated the total sediment oxygen demand, and thus the fast-decaying OM flux to the sediment surface. Sedimentary POC burial was calculated from sediment mass accumulation rate and the organic carbon content measured at the top of the sediment. The proportion of buried POC relative to total exported POC ranged at the most between 50% and 10%, depending on station location. Therefore, for a narrow geographic area like the Bay of Biscay, burial efficiency of POC was variable. A fraction of buried POC consisted of slow-decaying OM that was mineralized within the upper decimetres of sediment through oxic and anoxic processes. This fraction was deduced from the decrease with depth in POC concentration. At sites located below 500 m water depth, where the fast-decaying carbon did not reach the anoxic sediment, the slow-decaying pool may control the O2 penetration depth. Only refractory organic material was fossilized in sedimentary records at locations where labile OM did not reach the anoxic portion of the sediment.  相似文献   

17.
The paper presents a new model of electronic-vibrational kinetics of the products of ozone and molecular oxygen photodissociation in the terrestrial middle atmosphere. The model includes 45 excited states of the oxygen molecules O2(b 1, Σ g + ,v= 0−2), O2 (a 1Δ g , v= 0−5), and O2(X 3Σ g − , v= 1−35) and of the metastable atom O (1 D) and over 100 aeronomic reactions. The model takes into account the dependence of quantum yields of the production of O2(a 1Δ g , v= 0−5) in a singlet channel of ozone photolysis in the Hartley band on the wavelength of photolytic emission. Taking account of the electronic-vibrational kinetics is important in retrieval of the vertical profiles of ozone concentration from measured intensities of the Atm and IR Atm emissions of the oxygen bands above 65 km and leads to an increase in the ozone concentration retrieved from the 1.27-μm emission, in contrast to the previous model of pure electronic kinetics. Sensitivity analysis of the new model is made for variations in the concentrations of atmospheric constituents ([O2], [N2], [O(3P)], [O3], [CO2]), the gas temperature, rate constants of the reactions, and quantum yields of the reaction products. A group of reactions that most strongly affect the uncertainty of ozone retrieval from measured intensities of atmospheric emissions of molecular oxygen O2(b 1Σ g + , v) and O2(a 1Δ g , v) has been determined. Original Russian Text ? V.A. Yankovsky, V.A. Kuleshov, R.O. Manuilova, A.O. Semenov, 2007, published in Izvestiya AN. Fizika Atmosfery i Okeana, 2007, Vol. 43, No. 4, pp. 557–569.  相似文献   

18.
Seasonal depth stratified plankton tows, sediment traps and core tops taken from the same stations along a transect at 29°N off NW Africa are used to describe the seasonal succession, the depth habitats and the oxygen isotope ratios (δ18Oshell) of five planktic foraminiferal species. Both the δ18Oshell and shell concentration profiles show variations in seasonal depth habitats of individual species. None of the species maintain a specific habitat depth exclusively within the surface mixed layer (SML), within the thermocline, or beneath the thermocline. Globigerinoides ruber (white) and (pink) occur with moderate abundance throughout the year along the transect, with highest abundances in the winter and summer/fall season, respectively. The average δ18Oshell of G. ruber (w) from surface sediments is similar to the δ18Oshell values measured from the sediment-trap samples during winter. However, the δ18Oshell of G. ruber (w) underestimates sea surface temperature (SST) by 2 °C in winter and by 4 °C during summer/fall indicating an extension of the calcification/depth habitat into colder thermocline waters. Globigerinoides ruber (p) continues to calcify below the SML as well, particularly in summer/fall when the chlorophyll maximum is found within the thermocline. Its vertical distribution results in δ18Oshell values that underestimate SST by 2 °C. Shell fluxes of Globigerina bulloides are highest in summer/fall, where it lives and calcifies in association with the deep chlorophyll maximum found within the thermocline. Pulleniatina obliquiloculata and Globorotalia truncatulinoides, dwelling and calcifying a part of their lives in the winter SML, record winter thermocline (～180 m) and deep surface water (～350 m) temperatures, respectively. Our observations define the seasonal and vertical distribution of multiple species of foraminifera and the acquisition of their δ18Oshell.  相似文献   

19.
This paper reports that stoichiometric, amorphous, and uniform Er2O3 films are deposited on Si(001) substrates by a radio frequency magnetron sputtering technique. Ellipsometry measurements show that the refractive index of the Er2O3 films is very close to that of a single layer antireflection coating for a solar cell with an air surrounding medium during its working wavelength. For the 90-nm-thick film, the reflectance has a minimum lower than 3% at the wavelength of 600 nm and the weighted average reflectances (400--1000 nm) is 11.6%. The obtained characteristics indicate that Er2O3 films could be a promising candidate for antireflection coatings in solar cells.  相似文献   

20.
Physicochemical features of a typically meromictic lake, Lake Suigetsu, are studied. Vertical distributions of temperature and chlorinity show that the lake is well stratified, and no marked mixing occurs between the upper fresh water and lower salt water. In the chemocline, the vertical gradient of density is large, and the vertical eddy diffusion coefficient is as low as 1.5 × 10–2 cm2 sec.–1 Dissolved oxygen is saturated in the surface portion of the upper water, and then rapidly decreases with depth towards the chemocline, where sulfide first appears and increases towards the bottom. In the chemocline oxygen consumption is prominent process reaching 290 mg 02/m2/day. The oxidation of sulfide, supplied from the underlying water layer, is the main factor causing the oxygen consumption in the chemocline.  相似文献   

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