河北平原水系密度与隐伏活动构造的关系

以1926年出版的比例尺为1:5万的顺直地形图作为基础图件,用地理信息系统技术对河北平原作水系密度计量分析,揭示隐伏在第四纪巨厚的沉积物之下活动构造的信息。研究结果证实水系线密度统计图与使用其它地球科学方法获得的成果,例如基底活动断块图、地貌类型图和第四纪厚度图都有很好的对应,特别与布格重力图对应更好。研究结果发现水系密度图与布格重力异常图在总体一致性较好的前提下,多处反向异常区均为近代强震发生的区域。提出这种地表水系密度统计研究的成果不仅可以揭示深部隐伏的活动构造,而且具有较明确的时间含义。

利用ArcGIS生成水系密度的方法

介绍利用地理信息系统软件ArcGIS生成水系密度图的思路和方法。文章以DEM数据为基础,利用ArcGIS中的水文分析功能自动提取水系。水系经过与网格相交、重新统计总长度、连接等操作,最后得到水系密度图。以徐州地区为例,说明该方法的通用性与可行性。

利用水系密度方法研究徐州地区隐伏活动构造特征

以90 m分辨率的SRTM DEM数据为基础,利用Arc GIS软件提取徐州及其周围流域水系,并结合地形图进行校正与修改。用GIS空间分析技术对徐州地区做水系密度的统计分析,在此基础之上结合地质、深部特征、地震活动性分布等资料,研究徐州及其周围地区隐伏活动构造特征,得出研究区隐伏活动构造的规律,同时验证了水系密度等值线高梯度带,特别是梯度带的转弯及两个方向的交接部位是现代强震的分布地带;水系密度图与布格重力异常图的异常区均为近代强震发生的区域。为探索利用水系密度等值线图探讨徐州地区隐伏活动构造的特征提供了一定的借鉴意义,为揭示全新世以来平原覆盖层下地震构造及其活动的基本特征提供新的技术思路。

西北格陵兰冰盖英格尔菲尔德地区冰面-冰前流域水系遥感监测

近年来格陵兰冰盖物质损失加速,冰面消融是造成冰盖物质损失的重要原因。每年消融期,西北格陵兰冰盖表面都会形成规模庞大、结构复杂的冰面水系,将大量冰面融水输送至冰盖边缘,汇集至冰前水系并最终进入大洋,显著影响冰盖物质平衡。然而,目前对西北格陵兰冰盖冰面水系与冰前水系的研究很少,冰面水系与冰前水系的形态结构特征尚不清楚。本研究选取2018年7—8月西北格陵兰盖英格尔菲尔德地区(面积4 624 km^2)12景10 m空间分辨率的Sentinel-2卫星遥感影像,增强河流横纵剖面特征,提取了西北格陵兰冰盖的冰面水系与冰前水系,并以水系密度与河流宽度为代表性指标,监测冰面水系与冰前水系动态变化。结果表明:在2018年消融期内,西北格陵兰冰盖形成了平行状的冰面水系和树枝状的冰前水系;冰面水系由低高程地区(<800m)逐步向高高程地区(>1000m)推进;流域出口附近冰前河河宽与冰面水系密度的变化具有较好的一致性,8月份的冰前水系新发育河宽较窄(10~30m)的冰前河,反映了冰面水系对冰前水系的供给作用。

用GIS方法研究唐山和邢台地震区全新世隐伏活动构造

以 1 92 6年出版的顺直地形图 (1∶ 5万 )为基础图件 ,使用地理信息系统 (GIS)的方法 ,统计研究邢台和唐山两地震区地表水系的密度分布。早期的地形图较好地保留了原始水系形态 ,有利于提取隐伏构造活动的信息。 GIS技术具有信息量大 ,数据处理速度快的优点 ,做出的水系密度等值线图比较客观地反映了全新世以来平原覆盖层下地震构造及其活动的基本特征。本文介绍了基本研究思路和研究方法 ,并提供出邢台和唐山地震区的初步研究成果。

Determination of the Current System on Isopycnal Surface Between Mindanao and New Guinea from GDEM

In this study, we used the Navy’s Generalized Digital Environmental Model (GDEM) climatological temperature and salinity data on a 0.5°×0.5° grid to investigate the seasonal variabilities of the southwest Philippines Sea (0.5°–9°N, 123.5°–136.5°) thermohaline structure and circulation. The GDEM for the area was built up on historical (1930–1997) temperature and salinity profiles. A three-dimensional estimate of the absolute geostrophic velocity field on isopycnal surface was obtained from the GDEM temperature and salinity fields using the P-vector method. The seasonal variabilities of the thermohaline structure and currents (obtained from the inverse method) such as the Mindanao Current, Mindanao Undercurrent, North Equatorial Counter Current, New Guinea Coastal Undercurrent, and dual-eddies (cyclinic Mindanao Eddy and anticyclonic Halmahera Eddy) are identified.

Interactions between a cyanobacterial bloom (Microcystis) and the submerged aquatic plant Ceratophyllum oryzetorum Kom.

In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited by C. oryzetorurn, but no significant effect is found in this study.

Algal community composition and abundance near the confluence of the Jialing and Yangtze Rivers and in Shuanglong Lake in Chongqing,P.R.China

To understand the potential impact of the Three Gorges Reservoir on the aquatic ecosystem after the damming of the Yangtze River,we studied the community composition and temporal abundance distribution of algae in two types of water bodies:a segment of the Jialing River near its confluence with the Yangtze River as an example of the river-lake type,and Shuanglong Lake in Chongqing as an example of the lake type.In total,107 species belonging to 58 genera of 7 phyla were identified in the study area of the Jialing River,dominated by three groups with 49.5% diatoms,29.0% chlorophytes,and 11.4% cyanobacteria in the community composition.There were 122 species belonging to 66 genera of 8 phyla in Shuanglong Lake,dominated by the same three groups with 19.7% diatoms,48.4% chlorophytes,and 22.2% cyanobacteria.The densities of total algae and individual dominant groups were all much higher in the lake.More species of diatoms were found in the river-lake segment;whereas more chlorophyte species and cyanobacteriaum species were in the lake.There were 17 dominant species including 8 diatoms,4 chlorophytes,3 cyanobacteria and 2 cryptophytes in the river-lake segment,and 21 species in the lake,including 2 diatoms,9 chlorophytes,6 cyanobacteria,3 cryptophytes and a dinoflagellate.In eutrophic conditions,chlorophytes and cyanobacteria may proliferate in a lake-type area and diatoms may cause algal bloom in a relatively faster-flow lake-river type area.

Leak Detection in Water Distribution Systems Using Bayesian Theory and Fisher’s Law

A leak detection method based on Bayesian theory and Fisher’s law was developed for water distribution systems. A hydraulic model was associated with the parameters of leaks (location, extent). The randomness of parameter values was quantified by probability density function and updated by Bayesian theory. Values of the parameters were estimated based on Fisher’s law. The amount of leaks was estimated by back propagation neural network. Based on flow characteristics in water distribution systems, the location of leaks can be estimated. The effectiveness of the proposed method was illustrated by simulated leak data of node pressure head and flow rate of pipelines in a test pipe network, and the leaks were spotted accurately and renovated on time.

Effect of stocking density on performances of juvenile turbot (Scophthalmus maximus) in recirculating aquaculture systems

Limited information has been available about the influence of loading density on the performances of Scophthalmus maximus, especially in recirculating aquaculture systems （RAS）. In this study, turbot （13.84±2.74 g; average weigh±SD） were reared at four different initial densities （low 0.66, medium 1.26, sub-high 2.56, high 4.00 kg/m^2） for 10 weeks in RAS at 23±1℃ Final densities were 4.67, 7.25, 14.16, and 17.47 kg/m^2, respectively, which translate to 82, 108, 214, and 282 percent coverage of the tank bottom. Density had both negative and independent impacts on growth. The final mean weight, specific growth rate （SGR）, and voluntary feed intake significantly decreased and the coefficient of variation （CV） of final body weight increased with increase in stocking density. The medium and sub-high density groups did not differ significantly in SGR, mean weight, CV, food conversion rate （FCR）, feed intake, blood parameters, and digestive enzymes. The protease activities of the digestive tract at pH 7, 8.5, 9, and 10 were significantly higher for the highest density group, but tended to be lower （not significantly） at pH 4 and 8.5 for the lowest density group. The intensity of protease activity was inversely related to feed intake at the different densities. Catalase activity was higher （but not significantly） at the highest density, perhaps because high density started to induce an oxidative effect in turbot. In conclusion, turbot can be cultured in RAS at a density of less than 17.47 kg/m^2. With good water quality and no feed limitation, initial density between 1.26 and 2.56 kg/m^2 （final： 7.25 and 14.16 kg/m^2） would not negatively affect the turbot cultured in RAS. For culture at higher density, multi-level feeding devices are suggested to ease feeding competition.

Density and Viscosity of Ternary Systems(Poloxamer 188+Ethanol/ Acetone+Water)at Temperatures from 288.15 K to 308.15 K

The densities and viscosities of ternary systems(Poloxamer 188+ethanol/acetone+water)were meas- ured at 288.15,293.15,298.15,303.15,308.15 K and atmospheric pressure for different mass fractions of Poloxamer 188(0 to 0.02)in aqueous solution and different solvent volume fractions of ethanol/acetone(0 to 0.3)in Poloxamer 188 aqueous solution.The densities were measured by a pycnometer,while the viscosities were measured using two Ubbelohde capillary viscometers.The correlations of density and viscosity of these ternary systems are obtained by fitting the experimental data at different temperatures,mass fractions and volume fractions.

Densities and Viscosities of the Quaternary System Mannitol-Sorbitol- D-Glucose-H2O and Its Ternary Subsystems at 298.15K

To check the applicabilities of the simple density equation and viscosity equation in the semi-ideal solution theory to nonelectrolyte solutions, the densities and viscosities were measured for the quaternary system mannitol-sorbitol-D-glucose-HzO and its ternary subsystems mannitol-D-glucose-H2O and sorbitol-D-glucose-H2O at 298.15K. The results were used to test the applicability of the simple equations for the density and viscosity of the multicomponent nonelectrolyte solution. The agreements between the predicted and measured results are good.

Energy Storage System with Ultracapacitors for Thermal Underwater Glider

A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the control and sensor system.An electric energy storage system (ESS) is required which possesses high power density with good cycle life.Ultracapacitors which exhibit high power density and cycle life are considered as energy storage devices.Simulations based on a specific voyage condition indicate that ESS with ultracapacitors has positive effects on reducing the output power demand of PEMFC and lightening the power system.Experimental results show that the state of charge (SOC) is related to the capacitance and resistance in ultracapacitor ESS.

Experimental study on ultrasonic propagation in water-based bentonite slurry

Drilling fluid is a common flushing medium used in pile foundation, geological drilling and petroleum drilling. Study on ultrasonic propagation properties in drilling fluid is of vital importance, not only for developing equipments to non-contact measuring concrete casting level for bored pile, but also for developing equip- ments considering drilling fluid as signal channel. The existence of clay particles makes the ultrasonic propagation and attenuation in drilling fluid much different from pure water. In order to know the relation among ultrasound frequency, slun-y density and depth, a series of laboratory experiments about ultrasound propagation in water-based bentonite slurry were finished. Wavelet method was adopted to process the gained original waves of ultrasonic propagation in slurry, so we knew the velocity and attenuation coefficient of ultrasound propagated in different drilling fluids with different density. The first group experiments shows that with density of drilling fluid increase, ultrasonic velocity will decrease but attenuation coefficient will increase if ultrasonic frequency keep constant. The second group experiments shows that the power of ultrasound will intensify in small bore hole, the attenuation coefficient is much smaller than theoretical value.

In vivo effects of 17-β-estradiol on plasma immunoglobulin levels and leukocyte density in zebrafish Danio rerio

Estradiol, or 17-β-estradiol （E2）, the most potent naturally occurring estrogen, is involved in the hormone-immune system interaction in both mammals and fish. However, in vivo studies are largely limited, and little is known about whether E2 exerts similar effects on both female and male zebrafish （Danio rerio）. Here, we show exposure of both sexes ofD. rerio to 20 nmol/L E2 resulted in a significant increase in Vgl expression, but caused little damage to the hepatocytes, suggesting that this is the optimum E2 concentration. Also, exposure to 20 nmol/L E2 for 20 days caused a marked increase in plasma IgM levels, but had little influence on the peripheral leukocyte density, providing the first evidence of a hormone-immune system interaction in this species.

Measurement and modeling of the effective thermal conductivity for porous methane hydrate samples

The effective thermal conductivities of gas-saturated porous methane hydrates were measured by a single-sided transient plane source (TPS) technique and simulated by a generalized fractal model of porous media that based on self-similarity.The density of porous hydrate,measured by the volume of the sample in the experimental system,was used to evaluate the porosity of methane hydrate samples.The fractal model was based on Sierpinski carpet,a thermal-electrical analogy technique and one-dimensional heat flow assumption.Both the experimental and computational results show the effective thermal conductivity of methane hydrate decreases with the porosity increase.The porosity of 0.3 can reduce the thermal conductivity of the methane hydrate by 25%.By analysis of the experimental data and the simulative result,the optimized thermal conductivity of the zero-porosity methane hydrate is about 0.7 W m-1K-1.

Vegetable Production After Flooded Rice Improves Soil Properties in the Red River Delta, Vietnam

Vegetable production in South East Asia often is in rotation with flooded rice. The puddling of the soil with flooded rice production may result in unfavourable soil conditions for the subsequent production of dry land crops. To establish whether permanent vegetable production results in favourable soil conditions for vegetables, the effects of five different permanent vegetable production systems and a system of vegetable production in rotation with flooded rice on soil properties after flooded rice were studied in a 2-year field experiment. Bulk density at 0.05–0.10 m depth layer decreased with permanent vegetable production and vegetable production in rotation with flooded rice. The decrease in bulk density was influenced by the application of organic manure and rice husks, and especially by the number of crops cultivated, suggesting that frequency of soil tillage had a major effect on bulk density. Ploughing with buffalo traction after flooded rice, in combination with construction of raised beds, could reduce or totally eliminate negative effects of puddling on soil structure. Bulk density at 0.15–0.20 m soil depth was not influenced. Soil acidity decreased significantly in all systems. Soil organic carbon increased in all systems, but significant increase was only found in two permanent vegetable production systems. Available phosphorus(P) significantly increased in two permanent vegetable production systems, with a positively correlation to the amount of P applied. The significant decrease in bulk density and increase in p H(H2O), after only 2 years, showed that soil conditions after flooded rice could be improved in a short time under intensive vegetable production.

Solid electrolyte interphase in water-in-salt electrolytes

The water-in-salt strategy successfully expands the electrochemical window of the aqueous electrolyte from1.23 to~3.0 V,which can lead to a breakthrough in the energy output of the aqueous battery system while maintaining the advantage of high safety.The expanded electrochemical window of the water-in-salt electrolytes can be ascribed to the decreased water activity and the solid electrolyte interphase formed on the anode.The solid electrolyte interphase in the aqueous system is not fully understood,and the basic composition,the structure,and the formation mechanism are still cloaked in mystery.This perspective summarizes the published research with emphasis on the most possible formation mechanism and composition of the interphase layer in the aqueous system.Further understanding of the interphase as well as rounded assessment of the water-in-salt electrolyte in practical operating conditions is encouraged.The full understanding of the interface will guide the design of aqueous electrolytes and help to build novel aqueous batteries with high safety and high energy density.