The eastern sub-basin of the North Yellow Sea is an area with low degree of exploration, in which the Middle and Upper Jurassic dark mudstone is the main source rocks. The detailed evaluation of source rocks is very important for further exploration. Based on the sequence stratigraphy, by use the methods of organic geochemistry and organic petrology, the integrated study was conducted for the geochemical characteristics of the Jurassic source rocks in different sequences and different system tracts of the same sequence, and then the distribution law and main influencing factors of source rocks were discussed. The Middle and Upper Jurassic source rocks have high heterogeneity in the eastern sub-basin. The lithology of the source rocks is mainly dark mudstones of semi-deep lacustrine, deep lacustrine, and shore-shallow lacustrine in J₂SQ1 and J₂SQ2. Though these source rocks have high w(TOC), low w(S₁+S₂) and I_H,and the type of organic matter is poor, so these source rocks don't have high hydrocarbon generation potential in this basin. In general, the quality of the Middle Jurassic source rocks is medium to poor. The lithology of source rocks is mainly dark mudstones of delta front and shore-shallow lacustrine in J₃SQ1. The source rocks of J₃SQ1 have low w(TOC), and all of them are poor source rocks in different system tracts. The lithology of source rocks is mainly dark mudstone of semi-deep lacustrine, deep lacustrine in J₃SQ2, which is characterized by large thickness, high purity, and wide horizontal distribution. The w(TOC) of source rocks ranges from 0.5% to 5.3% in various system tracts of J₃SQ2. The high-quality source rocks are mainly developed in the high stand system tracts and extent system tracts, which are the most important oil source rocks in the eastern sub-basin. The studies indicate that the range of distribution is controlled by the sequential stratigraphic framework and the sedimentary facies. The quality of source rocks is controlled by the terrestrial matter input and the primary organic matter production of the lake basin. The preservation of organic matter is controlled by the oxygen content and salinity of lake water to a certain degree. In conclusion, the eastern sub-basin of the North Yellow Sea is an oil and gas bearing basin with medium-low abundance. The favorable exploration targets should be found in the high-quality hydrocarbon source rocks.

We studied the sedimentary strata and identified the sequential interfaces of the northern Jiangsu and South Yellow Sea basin by using lithology, well logging, paleontology and other data, and divided the Upper Permian-Lower Triassic strata of the research area into two large cycles (LC1 and LC2) and three intermediate cycles (MC1-MC3) based on continental shelf drilling program Well CSDP-2, in combination with Well N5, Well WX5-ST1 and typical section of Jiangning area in Nanjing under the theoretical instruction of sequence stratigraphy and sedimentology. This research shows that the South Yellow Sea basin and the northern Jiangsu basin are actually the same sedimentary basin separated by coastlines, and their Upper Permian-Lower Triassic strata are very well comparable. The LC1 large scale cycle has obvious asymmetry, and the highest base level MFS1 corresponds to the mudstone of shallow sea shelf facies in the middle and lower part of Longtan Formation. The LC2 large scale cycle was denuded by the Indosinian movement, and only half cycle of the basic-level rising remains. The study area mainly developed tidal flat, lagoon, delta and other marine and land transitional facies in the MC1 cycle (Longtan Formation), indicating the relatively stable water depth from place to place; however, during the MC2 and MC3 cycles (Dalong Formation and Qinglong Formation), the sedimentary facies such as shallow sea shelf, tidal flat, lagoon,and carbonate platform developed, and the water became deeper in the southwest and shallower in the northeast. This is the result of basin differential uplifts during Tungwu Movement.

The accurate description to sedimentary facies and its evolution of the complicated depositional environment can effectively guide the oil and gas field exploration and exploitation. Combined with the regional background of Weicheng structure in Dongpu depression, the depositional features and sedimentary model of the 4th member of Shahejie Formation (Es₄) in Wei 81 block of Weicheng oildfield were analyzed by use of the data of core description, logging, analysis and test, etc. It is considered that the associated sediments of terminal fan to beach-bar in shore-shallow lake are developed in the study formation of this block. The terminal fan was developed in the background of energy loss and flow fluctuation at the end of the rivers in the lower part of Es₄, and the distributary channel evolved into overflow or mudflat along the source direction,thus forming the fan-shape accumulation; with the change of sedimentary environment under the frequent expansion or shrink of the lake level, the beach-bar sediments in shore-shallow were developed in Es₄, paralleling to the trend of master fault with composite form.

The study on interlayers in fluvial reservoir plays an important guiding role in the reservoir architecture characterization and remaining oil development. Taking the block 6 of Gudong oilfield in Zhanhua sag as an example, the single well, profile,and plane characteristics of the distal braided river were analyzed by using core and wire logging. In order to analyze the interlayer patterns in the braided fluvial reservoirs, the interlayer characteristics in different hierarchical structures were identified by control of the microfacies and calibration of the well and core. The interlayer between single layers is physical, the interlayer between single sand bodies is physical or boulder clay, and the interlayer between the accretion bodies is silty mudstone. The silty interlayer in the braided bar is 80-400 m wide and 350-1 630 m long, and its inclinations at the bar head is about 2.03°, at the bar tail is about 1.28°, and at the wings is about 1.58°. Based on the constraints of the well network, the geometric parameters and occurrences of the interlayers in the braid bar were characterized, and the architectural model was built by the method of interface constraint, which can further characterize the heterogeneity of braided fluvial reservoir.

It is of great theoretical and practical significance for the classification of petroleum-bearing systems, the evaluation of favourable petroleum migration pathways, and the clarification of sweet spot for exploration to deepen the study of formation-pressure-structure in oil-bearing sedimentary basins and to clarify the spatial distribution of abnormal pressures. In order to carry out the secondary exploration of the oil-rich sags in Bohai Bay basin, we took Qikou sag as the research object and focused on its formation pressure structure. By calibrating the measured formation pressure, the single well formation-pressure-pattern analysis, the well-correlation profile analysis, and the 2-D seismic profile analysis were integrated to clarify the formation-pressure-pattern of Qikou sag. Four vertical formation-pressure-patterns were identified:the pattern with a single overpressure zone, the pattern with double overpressure zones, the pattern with multiple overpressure zones,and the hydrostatic formation pressure pattern. Vertically, there are three types of pressure systems in Qikou sag:single-overpressure-system, double-overpressure-system, and hydrostatic system. The double-overpressure-system is the main type of overpressure system in Qikou sag, which is widely developed in the main sag and the sub-sags. In the direction from the main sag to the edge of the basin, the double-overpressure-system gradually transits into the single-overpressure-system and the hydrostatic system. The single-overpressure-system is mainly distributed in the slope areas and the buried hills, such as Qibei high slope and Yangsanmu-Koucun buried hill. The hydrostatic system is mainly distributed in the Shenqingzhuang and Chengbei slope areas, farther away from the main sag. The seals of the upper and lower overpressure systems are located in Dongying Formation and Es₃ Formation, respectively. Laterally, the overpressure systems are controlled by the basin edges and deep faults. The formation of the upper overpressure system is mainly controlled by undercompaction, and is distributed in a ring around the main sag; while the formation of the lower overpressure system is mainly controlled by hydrocarbon generation, and is centered on the main sag and sub-sags. In the future, the main target of ultra deep gas exploration in Qikou area will be the natural gas stored in the lower overpressure system.

The Zaozigou gold deposit is located at the western part of the western Qinling Mountains in Gansu Province, and it is a super-large gold deposit discovered by regional geochemistry-national reconnaissance program in the 20th century. The deposit is a typical middle-low temperature magmatic hydrothermal deposit, and the orebody is mainly controlled by fault structures and dike rocks. In order to solve the Problem of deep prospecting, we were collected related data of 61 drillings and obtained 4 012 date of drimary halo in this paper. Through the correlation analysis, R-type cluster analysis, factor analysis, and zoning characteristics of primary halo, the best combination of indicator elements for gold prospecting is Au, As, Sb, Ag, Hg, W, while the closest and most direct indicator elements to gold mineralization are As and Sb. By calculating the index of primary halos, the axial zonation of this ore deposits is as follows (from high to low):Au-Hg-Bi-Pb-Mo-Sb-Ag-Cu-W-Zn-Co-As, and the reverse zoning phenomenon of the front elements (Sb, As) shows that blind ore bodies may exist in the deep. Base on the above studies and combined with geological knowledge, the ore-bearing potential and exact prospecting information in the deep were evaluated, the geological and geochemical deep prospecting model of the Zaozigou gold deposit was constructed, and finally two deep prospecting target areas were pointed out.

Through a field research,some new understandings have been obtained on the geology,ore body characteristics,surrounding rocks and rocks,ore characteristics, and mineral genesis of the Xiengkhor magnesite in Houaphanh Province,Laos. The exposed strata in the mining area are Lower Paleozoic (Pz₁),Middle Carboniferous-Upper Carboniferous(C_2-3),and Quaternary river secondary terrace deposits (Qp_Ⅱ^al). The main structure is a northwestward reverse fault and four northeast shift faults. The ore bodies are produced in the strong tectonic deformation zone on the southwest side of the reverse fault, and they are vein-like with the thickness of several millimeters,several centimeters, or ten centimeters. A total of ten ore bodies are circled. The surrounding rock of the ore body is the same as the rock type included in the ore body. It is a shallow metamorphic terrigenous clastic rock with high silicon(SiO₂=81.190%),low magnesium(MgO=0.781%),and rich iron (Fe₂O₃=11.716%,FeO=1.719%). The ore mineral is magnesite,and the gangue minerals are mainly quartz,phlogopite,dolomite,sericite, and limonite. It is inferred that the Xiengkhor magnesite was formed during the closure of the Middle Triassic-Late Triassic Paleo-Tethys ocean:The magnesia precipitated from the ultramafic rocks and formed the ore-bearing hydrothermal fluid; after enrichment,reticular magnesite was formed in the strong tectonic deformation zone. The genetic type of the Xiengkhor magnesite belongs to the Laoxieng-type crystalline magnesite hydrothermal deposit in shallow metamorphic clastic rocks. The metallogenic age is in Middle Triassic-Late Triassic.

The Late Carboniferous granites, including Dawusu and Fuxili plutons, consist of monzogranie and granodiorite. The LA-ICP-MS zircon U-Pb date indicates that the emplaced ages of these two plutons are (303.7±2.2)Ma and(300.5±0.5)Ma, formed by the Late carboniferous magmatism. The plutons are characterized by high silica (w(SiO₂)=66.77%-75.85%), alkali (w(Na₂O+K₂O)=7.41%-8.69%) and alumina (w(Al₂O₃)=12.90%-16.22%),with low MgO, CaO,and TiO₂. They are of calcalkaline series and peraluminous as indicated by A/CNK ratio of 1.06-1.44. Different from the aluminum-rich S type granite, no aluminum-rich minerals such as native muscovite, cordierite, and garnet were seen under the microscope. Conversely, the plutons show I type granite characteristics with negative correlation between P₂O₅ and SiO₂. The rocks are enriched in LREE, Ba, Rb and K with negative Nb, Ta and Ti anomalies, which is similar to that of the post-orogenic I type granitoids, indicating the plutons formed in an extensional tectonic environment. The w(⁸⁷Sr/⁸⁶Sr)ratio of the monzogranie is 0.712 938, and w(¹⁴³Nd/¹⁴⁴Nd) is 0.512 386 with the initial w(⁸⁷Sr/⁸⁶Sr)_i and ε_Nd(t)value of 0.704 4 and-1.09 respectively, indicating the source material is mainly the crust material from the depleted mantle. This is supported by the young Nd model age (T_DM2=1 172 Ma). Combined with the previous studies in the regional tectonics, the Dawusu and Fuxili plutons are related to the lithosphere extension after the orogenic collision between the Erguna-Xing'an block and the Songnen block.

The authors studied the Late Jurassic granitoids in the Chaihe region of central Great Xing'an Range. The Late Jurassic granitoids consist of granodiorite, monzonitic granite, and alkali-feldspar granite in lithology. We obtained two LA-ICP-MS zircon U-Pb ages of monzonitic granite, they are (152±1) Ma and (150±1) Ma respectively. The chemical analyses show that the Late Jurassic granitoids are classified as ferrous alkali-calcic rocks, and are characterized by enrichment in light rare earth elements (LREEs), large ion lithophile elements (LILEs), Zr, Hf, and depletion of heavy rare earth elements (HREEs), high field strength elements (HFSEs), Ba, and Sr, with weak to moderate Eu negative anomalies. All the geochemical characteristics suggest that the Late Jurassic granitoids were derived from the partial melting of lower juvenile crustal basaltic rocks. We propose that the generation of the Late Jurassic granitoids is related to the transitional environment of extrusion-extension after the final closure of the Mongol-Okhotsk Sea and subsequent continental thickening.

The volcanic rocks of Tamulangou Formation in New Barag Right Banner are mainly composed of basalt, basaltic andesite,and andesite. TIMS zircon U-Pb dating result shows that the volcanic rocks were formed in the Late Jurassic (ca. 154 Ma). The geochemical data show that the volcanic rocks belong to alkaline series, and have low contents of MgO (w(MgO)=0.55%-3.36%) and small amount of Mg^# (0.17-0.49); the chondrite-normalized rare earth element (REE) patterns indicate that the volcanic rocks are enriched in light rare earth elements (LREE) with significant fractionation of HREE from LREE ((La/Yb)_N=9.51-17.21) and insignificant Eu anomalies (δEu=0.78-1.04); the trace element geochemistry is characterized by enrichment of large ionic lithophile elements (e.g. Rb, Ba, K) and LREEs, depletion of high field strength elements (e.g., Nb, Ta, Ti),and compatible elements (Cr, Co, Ni). These characteristics suggest that the magma may be derived from partial melting of lithosphere mantle and metasomatized by subduction related fluids. Combined with the regional research results, we suggest that the volcanic rocks were formed under a lithospheric extension after the closure of the Mongol-Okhotsk Ocean.

The thin-bedded limestone,at the top of Xujiajuan Formation of Xiangshan Group in Ningxia, the western of Ordos basin, has become the pivotal stratigraphic unit to solve the age controversy of Xiangshan Group for some critical fossils found in Xujiajuan Formation. There has been an age controversy since the 1940s when the group was discovered, which now seriously blocks the research such as Early Paleozoic tectonics, stratigraphy and paleogeography in the northern Qilian area. The authors discussed the aqueous media from which these thin-bedded limestones were deposited based on the data of rare earth elements (REEs) and other trace elements. The results show that:1) the thin-bedded limestone can be divided into three types of A, B and C according to their REEs characteristics. 2) the positive Eu anomalies and negative Ce anomalies increase and decrease from type A to type C, respectively. 3) the geochemical indices of limestone change regularly from type A to type C, including the decrease of (La/La^*)_N, (Y/Y^*)_N, (Gd/Gd^*)_N, and Y/Ho ratios, the increase of the concentration of total REE and the ratios of light REE to heavy REE, the first increase and then decrease of (La/Yb)_N and (La/Sm)_N values, the increase of (Ce/Ce^*)_N values relative to the decrease of U/Th ratios, and the stability of Sr/Ba ratios relative to the distinct increase of Zr/Rb ratios. These geochemical changes suggest that the water media from type A to type C during deposition were characterized by:1)the attributes of seawater was decreased while the influence of terrigenous origin increased. 2)the depositional hydrodynamic intensity increased distinctively with variation of water depth. 3)the redox condition was from reduction to oxidation, and the water salinity was stable. Based on these interpretations of sedimentary aqueous media (seawater), sedimentary environments, and the significant positive Eu anomalies, the deposition of thin-bedded limestones perhaps occurred in an anoxic zone near the boundary of redox-stratified ocean and the internal-waves and internal-tides influenced by the sea floor hydrothermal plumes, which probably controlled the input of terrigenous material and the redox conditions, causing hydrodynamic oxygenation on the anoxic background.

This research is to study the sedimentary environment and geochemical characteristics of the Early Cambrian Mufushan Formation in Nanjing area. The relative sea level rise and fall of the Mufushan Formation is analyzed by using element geochemistry, isotopic characteristics of carbon and oxygen, records of paleo-salinity, paleo-water depth, and paleo-environment. The Mg²⁺/Ca²⁺ values of the Mufushan Formation has a negative correlation with the paleo-bathymetry. The values of Sr/Ba, 1000Sr/Ca and V/Ni show positive correlation with the paleo-salinity and paleo-water depth. The curves of paleo-salinity and paleo-water depth reflected by the values of Sr/Ba, 1000Sr/Ca and V/Ni indicate the cyclicity of the sea-level changes. The oxygen and carbon isotopes of the Mufushan Formation samples retain the original marine isotope composition. The δ¹³C_PDB values distribute between 0.8‰ and 3.5‰,with the mean of 2.55‰. The δ¹⁸O_PDB values distribute between -6.9‰ and -2.2‰,with the mean of -4.18‰. The δ¹³C_PDB values of the Mufushan Formation samples reflect the relative sea-level lift. Based on the values of Sr/Ba, 1000Sr/Ca, V/Ni,δ¹³C_PDB and the evolution of the sedimentary environment, the curves of relative sea-level lift of the Mufushan Formation are drawn. The Mufushan Formation underwent a transgressive-regressive cycle. The relative sea-level lift curve shows that the sea-level fluctuated frequently in the Mufushan period. The fluctuation is composed by three relative sea-level rises and three declines.

Based on the AMS¹⁴C dating and the phytoliths extracted from the 205 cm peat profile in the northern part of Dunhua, the paleoclimate environmental progresses of the study area near 2 ka were reconstructed,and the changing rules and influencing factors were discussed. The phytolith assemblages, ordered cluster analysis, and phytolith indexes showed that the peat swamp in the studied profile had experienced four significant stages:45-680 A. D. warm and wet stage; 680-1340 A. D. warm and dry stage; 1340-1870 A. D. cold and dry to wet stage; 1870-2017 A. D. warm, dry, and wet fluctuation stage. The paleoclimate condition in 680-1225 A. D. was similar to that in the Medieval Warm Period (MWP), and the condition in 1340-1870 A. D. was similar to that in the Little Ice Age (LIA). In such a climate context, the peat swamp developed a slow to gradually accelerated period. Compared with solar irradiation, stalagmite δ¹⁸O sequence,Niño3.4, and the paleotemperature reconstruction in Northeast China, the phytolith analysis in the studied peat profile indicated that the paleoclimate process during MWP and LIA was controlled by solar activity, solar irradiation, monsoon circulation, and ENSO (El Niño-Southern Oscillation).

The breaching process of natural dams is influenced by many factors. However, it is still unclear about the effects of initial soil moisture on the discharge hydrograph and breach evolution. In this study, we conducted several laboratory tests to study how the initial soil moisture influences the breaching process of natural dams. The results show that there were three periods with different breaching characteristics in the breaching process with different initial soil moistures, namely the tractive erosion, the backward erosion, and the water and sand movement rebalance. The peak discharge increased with the increase of initial soil moisture. However, the breaching duration and dam height after dam failure decreased with the increase of initial soil moisture. The intensity of backward erosion decreased with the increase of initial soil moisture;in contrast, the tractive erosion enhanced with the increase of initial soil moisture. The greater the initial soil moisture was, the larger the incision rate was, and the incision rate increased slowly when the initial soil moisture was less than 7.8%, otherwise the incision rate increased quickly. In addition, the average incision rate at an initial water content of 10.3% was twice that of the initial water content of 7.8%. The ratio of breach width to depth decreased as the initial soil moisture increased before the last period. The ratio of breach width to depth after dam failure decreased with the increasing of initial soil moisture, which tended to be 1.00 and then less than 1.00 with increasing of the initial soil moisture.

Taking the planning of the central urban area in Luzhou City as the research area, we firstly established the building suitability evaluation method, which includes multiple factors, comprehensive evaluation model, and multi hierarchy evaluation index system, secondly calculated the weight of evaluation factors based on Fuzzy weighting and APH, and then evaluated the building suitability of the research area combined with the statistical methods and GIS spatial analysis techniques, finally analyzed the reliability of the evaluation methods. The results indicate that the evaluation method is suitable for hilly urban building suitability evaluation. The suitable area accounts for 36.16% of the total area, the relatively suitable area accounts for 28.81%, the poor area accounts for 20.96%, and the unsuitable area accounts for 8.07%. The building suitability of the research area is well. The planning and construction and the site selection of major construction in Luzhou City should be in the suitable area or relatively suitable area. If the construction and major construction site is in a poor area and unsuitable area, the attention should be paid to the prevention and control of the existing and possible geological disasters induced by uneven settlement of foundations, soft soil, and collapse in different sections.

The effect of the traditional groundwater level prediction model is not ideal due to the lack of considering the temporal and spatial variation rules and the relevant influencing factors of groundwater level.The authors used the long and short term memory neural network (LSTM), adopted the method of multivariable input,and constructed the groundwater level prediction model. Taking the monitoring Well J1 in Daiyue district of Tai'an City as an example, the groundwater level dynamic monitoring data from 2001 to 2014 and the relevant influencing factor data were used to predict the groundwater level from 2015 to 2016 by using the multivariable LSTM neural network, and further compared with the single variable LSTM neural network model and BP neural network model. The research results show that the BP neural network prediction model can only make the corresponding prediction according to the change of the influencing variables without considering the change rule of timing sequence, so the prediction error is large (2.399 3). The single-variable LSTM model only takes the groundwater level as the variable input with no considering the influence of relevant factors, and the prediction error is 2.102 2. The prediction accuracy of the LSTM neural network prediction model based on multivariable input is significantly higher than that of the univariate LSTM neural network and BP neural network models, and the prediction root mean square error is only 1.919 1, which successfully verifies the accuracy of the multivariable LSTM neural network groundwater level prediction model.

Gudui Spring is the only low medium temperature geothermal spring in Fenhe River basin. The research of hydro-geological characteristics and demarcation of karst groundwater system is the basis of karst groundwater resource evaluation. On the basis of the geological structural and hydro-geological characteristic analysis and karst groundwater circulation, the Gudui Spring karst groundwater system and subsystem are preliminarily delimited. The results show that the geological structures of the Gudui Spring karst system are complicated, and there are a lot of intrusive igneous rocks and buried faults. The overall geological structure of the system can be described as three uplifts and three subsides both in east-west and north-south directions. The recharge of karst groundwater is mainly from the precipitation of carbonate outcrop areas in Taer Mountain, Erfeng Mountain and Zhongtiao Mountain. Nanliang Spring and Haitou Spring are two local discharge areas;while Gudui Spring is the final discharge area. The boundary of Gudui Spring karst groundwater system and its hydrogeological nature are delimited by using the method of hydro-geological and groundwater circulation characteristic analysis. The area of Gudui Spring karst system is 2 942 km² and can be divided into four relatively independent systems. The first is Taer Mountain-Jiuyuan Mountain Gudui Spring karst subsystem, the second is Foling Mountain-Gaoxian Haitou Spring karst subsystem, the third is Zhongtiao Mountain Nanliang Spring karst subsystem,and the last is Houma Basin deep circulation karst groundwater subsystem.

In order to study the co-migration characteristics of natural soil colloids and Ni²⁺ in a groundwater system, the effect of natural soil colloids on the migration of Ni²⁺ in groundwater and the influence of pH, ionic strength (IS), and organic matter on the adsorption of Ni²⁺ by soil colloids were analyzed by means of static adsorption experiments and column technique of quartz sand simulation medium. The results show that the adsorption of heavy metals on soil colloids was increased by increasing pH, but reduced significantly by the increase of ionic strength; the adsorption capacity of colloids on Ni²⁺ was increased by the presence of humic acid; in the presence of colloids, the time of the Ni²⁺ penetrating sand column was shortened, the adsorption capacity of soil colloids was enhanced, and the amount of adsorption was increased; however, when the ionic strength increased, although the time of Ni²⁺ penetrating through the sand column was shortened, the amount of adsorption was decreased.

The reduced graphene oxide (rGO) doped and Ag-TiO₂ based photoelectrodes were prepared to study the effect of the composite method on the electron transport and tetracycline degradation by photocatalyst. The electrodes were characterized by electrochemical impedance spectroscopy and Mott-Schottky curve. The results showed that the interface resistance of the double-layer/thin film was reduced by the layered composite method on the surface of the carrier; while the total charge transfer resistance was mainly reduced by the fully mixed composite method. In addition, the concentration of the electron donor increased with the increasing of composite amount. When the rGO mass fraction was 0.45% and 0.25%, the degradation rate of tetracycline by the layered composite and the fully mixed doped electrode was 11.4% and 2.3% higher than that of Ag-TiO₂, respectively. Under the applied 0.5 V bias voltage, the LG6 degradation efficiency of the layered composite electrode was increased by 5.3%; while the MG2 efficiency of the fully mixed composite electrode was not improved. The layered composite method can improve the electron transport efficiency more effectively on the surface of photocatalyst.

In order to optimize the process parameter of high loaded bioflocculation-membrane reactor (HLB-MR) and improve its efficiency of recovering organics in municipal wastewater, the organics removal, bioflocculation, organics recovery, and membrane fouling of the reactor were investigated under different solid retention time (t_SR) in parallel. When the HLB-MR operated at t_SR of 0.2, 0.6, and 1.0 d respectively, all the efficiencies of organics removal reached above 85% and the chemical oxygen demands (COD) of permeate were all stable at around 30 mg/L. The bioflocculation effect was enhanced with the extension of t_SR, and the flocculation efficiency of colloid COD increased from 66% when t_SR was 0.2 d to 95% when t_SR was 1.0 d. The mineralization loss rate of organics increased gradually from 6.9% when t_SR was 0.2 d to 10.5% when t_SR was 1.0 d, while the recovery rate of total COD decreased gradually. The membrane fouling potential of the concentrate in the reactor was gradually alleviated with the extension of t_SR, which was related to higher EPS yield, better bioflocculation effect and lower particle fraction of fine particles (0-1 μm) under a longer t_SR in the reactor. Compared with 0.2 d and 1.0 d, 0.6 d was considered to be optimal t_SR of the HLB-MR from a comprehensive perspective. Under this condition, the flocculation efficiency of COD was up to 90%, the membrane fouling was relatively light, the total COD loss rate was as low as 7.4%, and the recovery rate of total COD could be as high as 80% if the loss of organic matter was ignored during the membrane cleaning.

During the survey of fixed-wing airborne electromagnetic system, the transmitting and receiving coils are rotated by wind direction, flight bumpy etc., which makes the change of coil attitude,and it,in turn,causes error to receiving electromagnetic responses. Based on Faraday's law of electromagnetic induction, by using the transformation relationship between the coil coordinate system and the system coordinate system, we deduced the formula for calculating electromagnetic response,and concluded that electromagnetic response is composed of two parts:The dynamic response generated by cutting geomagnetic field in the movement process of coil and the static response induced in the sloping coil. We further studied the coil attitude correction algorithm based on BP neural network through the following steps:Firstly, the dynamic response was removed through calculation by using geomagnetic field and coil attitude angle,then BP neural network model was constructed, and the static response was corrected by using of the static response coefficient obtained in the network. The simulation results show that the quality of the corrected electromagnetic response data is greatly improved.

The Nenjiang-Balihan fault is an important fault on the western margin of Songliao basin. It is of great significance to study the formation and evolution of the Meso and Cenozoic basins in the region. The previous research on the deep structural characteristics of the Nenjiang-Balihan fault is relatively inadequate, as it is covered by thick sediments. In this study, one MT (magnetotelluric sounding) line and one seismic profile across the Nenjiang-Balihan fault were processed and interpreted, and in combination with the regional drilling data, the structural characteristics of the deep and shallow parts of the fault were obtained. The results show that the deep electrical structures along the MT profile are horizontally bounded by an "eight-shaped" low resistance band and corresponded well to the geological units. It is inferred that the east-dipping low-resistivity strip L₃ represents the Nenjiang-Balihan fault with the characteristics of concealment, ultra-crust, shallow high angle, etc. The whole fault is composed of two east-dipping anti-Y-type faults and one west-dipping fault, in a flower-like structural style, indicating that the faults have experienced a strong compressive stress environment.

Landslide is one of the most important types of geological hazards. It is of great significance to find out the geological and geophysical characteristics of a landslide area for analyzing the formation mechanism of a landslide and evaluating its stability. In view of this, the high-density resistivity method was first introduced into the landslide geological survey of Wanzhou area in the hinterland of the Three Gorges Reservoir area, and the geophysical exploration of Sifangbei landslide, Tangjiao No. 1 landslide, and Maliulin landslide was carried out in the area. The measured results were compared and verified with borehole data. Through data inversion and analysis, the stratum structure and slip surface of landslide bodies are obtained; By combining with the relevant geological data and comparative interpretation, it can make up for the deficiency of only relying on borehole information to determine the shape of slip surface; According to the measured data of the three typical landslide areas, the geophysical and electrical characteristics of landslide mass and sliding bed are as follows, resistivity of landslide mass composed of colluvium, quaternary silty clay and water bearing gravel block is less than 40 Ω·m, while resistivity of sliding bed composed of sandstone and mudstone is more than 40 Ω·m. It is proved that the high-density electrical method can get better results for both bedrock landslide and soil landslide.

The microscopic characteristics of carbonate reservoirs cannot be easily described due to the limitation of existing geophysical data scale. By using the critical porosity model as rock physical theory, the relationships between pore structures and elastic responses were built, and the key parameters were estimated through statistical method. Furthermore, the experiments were used to classify logging data with their critical porosities. The results indicate that the accuracy and stability of this new method (error less than 10%) meet the needs of carbonate reservoir exploration at Log YS1. It provides a new method to reduce the pore complexity and inversion uncertainty, and has reference value for geological interpretation.

In recent years, the technology of Rayleigh-waveform inversion is highly valued by scholars, because the wave field is calculated and inverted directly without the calculation of conventional dispersion curves. In other words, the waveform inversion method is no longer limited by the theoretical assumption of horizontal layered media. Rayleigh waveform inversion requires repeated forward and inverse calculations of wave field; in addition, due to the small velocity of the shallow surface, the simulation requires a small grid space to avoid numerical dispersion, which undoubtedly greatly increases the forward modeling calculation amount. Based on the idea of message passing interface (MPI) method, we applied a parallel finite-difference algorithm to wave field simulation to improve the computation efficiency of the forward modeling. Firstly, the whole calculation region was decomposed into several sub-regions; and then, the wave field was computed for each sub-region; finally, the whole wave field was completed together by communicating among sub-regions. In this paper, the detailed implementation methods and steps of the parallel schemes, such as region decomposition, coordinate transformation, region communication, and wave field combination and so on, are given. The analyzing results of the different parallel schemes in elastic model, Kelvin and standard linear solid (SLS) viscoelastic model show that our parallel scheme is feasible and effective. The parallel computation results indicate that multiple processors can significantly reduce the computing time compared with a single processor; however, the communication time between different processors also increases. It is necessary to select the appropriate number of processors in the parallel process. For viscoelastic medium model, the parallel computation efficiency of SLS viscoelastic model is better than that of Kelvin viscoelastic model.

Object-oriented image segmentation is the premise of information extraction and classification, and its scale parameter setting directly affects the accuracy of extraction and classification. Taking GF-2 image data as an example, this paper presented a new optimal scale model based on the existing segmentation theory and method. By taking the obtained components of the principal component analysis and the newly built NDVI feature layer as the segmentation reference layers, the authors carried out multi-scale segmentation. In consideration with the influence of shape factor and compactness factor comprehensively, the weighted scale assessment index was constructed, and the cubic spline interpolation was used to fit the optimal segmentation scale. Finally the error coefficient (E_c) was proposed to compare the new model with the original model. The results show that the error coefficient of the OS model (E_c=1.15%) is smaller than that of the original model (E_c=3.28%), and the segmentation objects of the OS model are closer to the ground truth. This model provides an objective basis for the setting of scale parameters, avoids the subjectivity of traditional parameter selection, and improves the image segmentation quality.