Numerical Approaches to Identification of Characteristic Soil Layers in an Urban Environment

Pedogenetic soil horizons are one of the fundamental building blocks of modern soil classification; however, in soils of urban areas which are often strongly disturbed by human activities, horizons are difficult to distinguish but substitutive morphological layers may be identified. To identify the characteristic soil layers in an urban environment, 224 soil layers of 36 in-situ pedons were examined and described in urban and suburban Nanjing, and 27 variables were extracted for multivariate analysis. Three groups and six subdivisions were identified by TwoStep cluster analysis combined with hierarchical cluster analysis based on factor scores. Soil forming factors and soil forming processes could be interpreted from the principal component analysis （PCA） of variables, cluster analysis of soil layers, and discriminant analysis of soil layer groups and their subdivisions. Parent materials, moisture regimes, organic matter accumulation, and especially nutrient accumulation were the main causes of characteristic soil layer formations. The numerical approaches used in this study were useful tools for characteristic soil layer identification of urban soils.

Geological Characteristics of Potassium-Bearing Salt Layers in the Well Block Quele of the Kuqa Depression and their Significance

Potash is one of the long-term scare deposits in China,and potash prospecting has long been listed as a key brainstorm project for our nation and geological prospecting units.There have been considerable studies in search for potash deposits in the Kuqa depression of the Tarim basin(Jackson et al.,1991;Gemmer et al.,2004;Vendeville,2005;Vendeville and Jackson,1992a,1992b),

Characteristic Study of the Boundary Layer Parameters over the Arabian Sea and the Bay of Bengal Using the QuikSCAT Dataset

The marine atmospheric boundary layer （MABL） plays a vital role in the transport of momentum and heat from the surface of the ocean into the atmosphere. A detailed study on the MABL characteristics was carried out using high-resolution surface-wind data as measured by the QuikSCAT （Quick scatterometer） satellite. Spatial variations in the surface wind, frictional velocity, roughness parameter and drag coefficient for the different seasons were studied. The surface wind was strong during the southwest monsoon season due to the modulation induced by the Low Level Jetstream. The drag coefficient was larger during this season, due to the strong winds and was lower during the winter months. The spatial variations in the frictional velocity over the seas was small during the post-monsoon season （-0.2 m s^-1）. The maximum spatial variation in the frictional velocity was found over the south Arabian Sea （0.3 to 0.5 m s^-1） during the southwest monsoon period, followed by the pre-monsoon over the Bay of Bengal （0.1 to 0.25 m s^-1）. The mean wind-stress curl during the winter was positive over the equatorial region, with a maximum value of 1.5×10^-7 N m^-3, but on either side of the equatorial belt, a negative wind-stress curl dominated. The area average of the frictional velocity and drag coefficient over the Arabian Sea and Bay of Bengal were also studied. The values of frictional velocity shows a variability that is similar to the intraseasonal oscillation （ISO） and this was confirmed via wavelet analysis. In the case of the drag coefficient, the prominent oscillations were ISO and quasi-biweekly mode （QBM）. The interrelationship between the drag coefficient and the frictional velocity with wind speed in both the Arabian Sea and the Bay of Bengal was also studied.

CHARACTERISTICS OF BOUNDARY LAYER AND ITS EFFECTS ON ATMOSPHERIC AEROSOL CONCENTRATIONS IN DONGGUAN, GUANGDONG

The structure of atmospheric boundary layer determines the ability of atmospheric dispersion and has an essential impact on airborne aerosols.In this paper,the data of a radio sounding experiment held in Dongguan National Meteorological Observation Station,which is in a coastal city in Pearl River Delta,as well as the data of atmospheric aerosols,were utilized in order to analyze the characteristics of atmospheric boundary layer and its effects on surface aerosol concentrations.The results are showed at follows:the local circulations,associated with dominant winds,made complex structures of atmospheric layers,as the cold air and systematic winds weakened in the end of a cold air event.Weakened wind shears and inversion layers,especially a strong near-surface inversion layer,remarkably diminished the atmospheric diffusion abilities and facilitated an especially high concentration of surface aerosols.The convergence line or weak shear line of sea breeze in the ground level helps weaken the atmospheric diffusion abilities and results in atmospheric aerosols accumulation.

Large eddy simulation on the flow characteristics of an argon thermal plasma jet

Large eddy simulations based on the CFD software Open FOAM have been used to study the effect of Reynolds number and turbulence intensity on the flow and mixing characteristics of an argon thermal plasma jet.Detailed analysis was carried out with respect to four aspects:the average flow field,the instantaneous flow field,turbulence statistical characteristics and the selfsimilarity.It was shown that for the argon thermal plasma jet with low Reynolds number,increasing the turbulence intensity will increase the turbulent transport mechanism in the mixing layer rather than in the jet axis,leading to the faster development of turbulence.The effect of the turbulent transport mechanism increases with increasing Reynolds number.However,the characteristics of flow and mixing are not affected by turbulence intensity for high Reynolds number situations.It was also found that the mean axial velocity and mean temperature in the axis of the turbulent thermal plasma jet satisfy the self-similarity aspects downstream.In addition,decay constant K is 1.25,which is much smaller than that(5.7-6.1)of the turbulent cold gas jet and has nothing to do with the Reynolds number or turbulence intensity in the jet inlet.

ON GOLD-BEARING CHARACTERISTICS OF GEOSYNCLINAL TECTONIC LAYER IN XUEFENG MOUNTAIN TECTONIC BELT,HUNAN,CHINA

1. Material composition of the geosynclinal tectonic LayerThe geosynclinal tectonic layer is mainly composed of the following two parts: sandyslate rocks of Precambrin and volcanic rocks inbeded within the sand-slate rocks.The sandy-slate rocks embrace the chemical compositional characteristics of light metamorphic rocks: SiO2=54.5681.63（Wt%）, with average of 63.96（wt%）（n=58, the same as following）; Al2O3=9.4717.75（wt%）, with average of 15.36（wt%）, and Al2O3】K2O+Na2O+CaO; the content of （FeO+Fe2O3） varies greatly with FeO】Fe2O3; （CaO+MgO）=0.789.22 （wt%）with average of 23 （wt%）, and MgO】CaO; the ratios of K2O/Na2O rang from 2 to 4（】1）. By comparing all this chemical data with that of the other kind rocks, We can know that the sand y-slate rocks were the eunic and /or bathyal sediments which formed under the strongly active eugeosynclinal tectonic setting.

Vertical Atmospheric Structure of the Late Summer Clear Days over the East Gansu Loess Plateau in China

In this paper, by using the sounding data collected in LOPEX05, we have analyzed the vertical atmospheric structure and boundary layer characteristics of temperature and humidity in the late summer over the east Gansu loess plateau. The results show that the bottom of the stratosphere is at about 16 500 m and varies between 14 000 m and 18 000 m above the ground. The center of the westerly jet is located between 8300 m and 14 300 m above the ground and its direction moves between 260~ and 305~. There is an inverse humidity layer at about 3000 m height above the ground. The maximum of the air temperature occurs at 1700 LST in the layer below 800 m above the ground. The inversion layer is relatively thick. The time that the maximum of the vapor occurs is not the same for different layers. The depth of the atmospheric boundary layer can reach about 1000 m and the depth of the stable boundary layer can be 650 m.

THE SEISMIC PROFILER FOR DEEP SEDIMENT LAYERS AND ITS CHARACTERISTICS

DDCl-1 type seismic profiler for deep sediment layers is a large scale marine survey equipment. Its penetrating strata depth may reach to 1 km. This equipment suits surveys for continental shelf,seafloor trench and geological structure under seafloor etc. It suits also geological environment surveys of seafloor resources.The working principle, block diagrams composition and echo signal processing characteristics are presented, and some typical strata profiles are shown.

SOME EXPERIMENTAL STUDIES OF BOUNDARY LAYER CHARACTERISTICS ON THE OVERFLOW DAM BY LDA

The velocity profiles at six different cross sections and the development of the boundary layer over the surface of the overflow dam are given.Based on the experimental data using laser fcchnique the boundary layer thickness expression is derived.The velocity distributions within the boundary layer nearby the bottom of the dam are ana- lyzed.The fluctuating pressure on the overflow dam is compared with the fluctuating velocity nearby the bottom of the dam.

Organic–inorganic Au/PVP/ZnO/Si/Al semiconductor heterojunction characteristics

The paper reports the fabrication and characterization of a novel Au/PVP/ZnO/Si/Al semiconductor heterojunction（HJ） diode. Both inorganic n type ZnO and organic polyvinyl pyrrolidone（PVP） layers have grown by sol-gel spin-coating route at 2000 rpm. The front and back metallic contacts are thermally evaporated in a vacuum at pressure of 10^-6 Torr having a diameter of 1.5 mm and a thickness of 250 nm. The detailed analysis of the forward and reverse bias current-voltage characteristics has been provided. Consequently, many electronic parameters, such as ideality factor, rectification coefficient, carrier concentration, series resistance, are then extracted.Based upon our results a non-ideal diode behavior is revealed and ideality factor exceeds the unity（n 〉 4）. A high rectifying（-4.6 × 10^4） device is demonstrated. According to Cheung-Cheung and Norde calculation models, the barrier height and series resitance are respectively of 0.57 eV and 30 kΩ. Ohmic and space charge limited current（SCLC） conduction mechanisms are demonstrated. Such devices will find applications as solar cell, photodiode and photoconductor.

THE PHYSICAL STRUCTURE OF THE WINTER FOG IN CHONGQING METROPOLITAN AREA AND ITS FORMATION PROCESS

Chongqing is a very famous foggy metropolitan in China.The Chongqing Fog Experiment Group carried out com- prehensive experiments on a large and extensive scale in the Chongqing urban area from 15 December 1989 to 15 Janua- ry 1990.And several items were further observed from 7 December 1990 to 7 January 1991.Based on the analysis of the observational data,some important characteristics of the Chongqing winter fog and the boundary layer structure have been revealed.It is found that such factors as topography,mountain wind,rivers,the urban heat island and air pollution,all contribute to the formation of the Chongqing fog in addition to the radiation conditions.

Efficient dye-sensitized solar cells from mesoporous zinc oxide nanostructures sensitized by N719 dye

Dye-sensitized solar cells（DSCs） have attracted a great deal of attention due to their low-cost and high power conversion efficiencies. They usually utilize an interconnected nanoparticle layer of TiO2 as the electron transport medium. From the fundamental point of view, faster mobility of electrons in Zn O is expected to contribute to better performance in DSCs than TiO2, though the actual practical situation is quite the opposite. In this research, we addressed this problem by first applying a dense layer of Zn O on FTO followed by a mesoporous layer of interconnected Zn O nanoparticle layer, both were prepared by spray pyrolysis technique. The best cell shows a power conversion efficiency of 5.2% when the mesoporous layer thickness is 14 μm and the concentration of the N719 dye in dye coating solution is 0.3 m M, while a cell without a dense layer shows 4.2% under identical conditions. The surface concentration of dye adsorbed in the cell with a dense layer and that without a dense layer are5.00 × 10^（-7） and 3.34 × 10^（-7） mol/cm^2, respectively. The cell with the dense layer has an electron lifetime of-54.81 ms whereas that without the dense layer is 11.08 ms. As such, the presence of the dense layer improves DSC characteristics of Zn O-based DSCs.