The Temporal and Spatial Evolution Characteristics Analysis of Jiangsu Tourism Economy

[Objective] The paper aimed to reflect the spatial pattern and temporal and spatial evolution characteristics, the differences between inter-regional tourism economy was measured from the quality aspect, which provided a reference for the local governments in the future tourism development. [Method] Using the location entropy methods, three time periods side of tourism-related date of 2000, 2005, 2007 were selected, from the angle of the spatial pattern and the evolution of the differences within the different scales, the spatial and temporal evolution characteristics of the economic development level of Jiangsu were analysed. [Result] The results showed that from the aspect of spatial evolution pattern, as time goes on, the economic development of Jiangsu tourism has experienced morphological evolution of concentration- dispersion decrease-stability; when it comes to the development of the tourism economy, in recent years, the overall gap between the tourism economy in Jiangsu did not widen, the gap mainly led by the region one after another. According to their volatility, it will be divided into four categories: A Stable type (Wuxi, Xuzhou, Lianyungang and Taizhou), B Increasing type (Huai’an), C Fluctuations type (Nanjing, Changzhou, Suzhou and Yangzhou) and D Depression type (Nantong, Yancheng, Zhenjiang and Suqian). [Conclusion] Location entropy was quoted into tourism economic analysis, the method was simple and easy to understand, the result was accurate and convincing, which provided a reference for travel economic development and investment decision-making of Jiangsu.

Evolution Characteristics and Development Trends of Sand Barriers

Sand barriers are one of the main measures used to prevent desertification and have been widely used in desertification control. Here, we use bibliometric methods and content analysis to summarize sand barrier type, applications and research. Existing problems in research are pointed out and revolution characteristics and development trends of sand barriers are discussed. We conclude that three main driving factors have stimulated sand barrier study： demand, technology and development concept. Developing environmentally friendly technology and promoting industrialization of sand area economies are future directions for sand barrier research.

Spatiotemporal Evolution Characteristics Study on the Precipitation Infiltration Recharge over the Past 50 Years in the North China Plain

The spatiotemporal evolution characteristics of precipitation infiltration recharge during the past 50 years are discussed in this paper. This research is significant for groundwater resource rational utilization. The distribution of precipitation infiltration recharge coefficients in the 1960 s, 1980 s, and 2000 s can be obtained using unsaturated zone lithology and depth to water table at different times. The amount of precipitation infiltration recharge in the 1960 s, 1980 s, and 2000 s can be calculated using precipitation infiltration recharge coefficients and precipitation data from the Ministry of Water Resources of China. Results show that the change in the precipitation infiltration recharge coefficient is closely related to the water table decrease. From the 1960 s to the 1980 s, the precipitation infiltration recharge coefficient clearly increased in all units. From the 1980 s to the 2000 s, the value slightly increased in the ancient Yellow River alluvial-proluvial and eastern alluvial-marine plains and slightly decreased in the piedmont alluvial-proluvial and central alluvial-lacustrine plains. The piedmont alluvial-proluvial and ancient Yellow River alluvial-proluvial plains exhibited a large precipitation infiltration recharge coefficient for the coarse lithology. The amounts of precipitation infiltration recharges were 16.23×109（1960s）, 19.11×109（1980s）, and 19.42×109 m3/a（2000s）. The amount of precipitation infiltration recharge increased from the 1960 s to the 1980 s then decreased from the 1980 s to the 2000 s in the piedmont alluvial-proluvial and the central alluvial-lacustrine plains. However, this value increased from the 1960 s to the 2000 s in the ancient Yellow River alluvial-proluvial and eastern alluvial-marine plains.

Characteristics of Geochemical Evolution of Trace Elements and REE in Gejiu Granites, Yunnan Province

The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite monzonitic granite(stageⅠ),medium-coarse-grained biotite-K-feldspar granite(stage Ⅱ)and two-mica alkali-feldspar granite(stage Ⅲ)are thought to have been formed successively from the samegranite magma source through fractional crystallization(Rayliegh fractionation),because linear correlationsare found between log(Rb/Sr)-log Sn,log(Rb/Ba)-log Sn,log(Rb/Ba)-log(Rb/Sr),log La-log Sr,log Ce-log Sr,log Eu-log Sr,etc In addition.the characteristics of REE distribution patterns in these three major types ofgranites also reflect the magmatic differentiation features of Gejiu granites.Of the three major types,the twomica alkali-feldspar granite of stage Ⅲ nuderwent the strongest differentiation,and thus has the closestgenetic relationship with the Gejiu tin-polymetallic ore deposit Such tin-polymetal mineralized granites arecharacterized by high Rb/Sr and Rb/Ba ratios,low K/Rb and ∑Ce/∑Y ratios and remarkable Eu depletion.

South China Sea Typhoon Hagibis enhanced Xinfengjiang Reservoir seismicity

There was an evident increase in the number of earthquakes in the Xinfengjiang Reservoir from June to July 2014 after the landing of Typhoon Hagibis.To understand the spatial and temporal evolution of this microseismicity,we built a high-precision earthquake catalog for 2014 and relocated 2275 events using recently developed methods for event picking and catalog construction.Seismicity occurred in the southeastern part of the reservoir,with the preferred fault plane orientation aligned along the Heyuan Fault.The total seismic energy peaked when the typhoon passed through the reservoir,and seismicity correlated with typhoon energy.In contrast,a limited seismic response was observed during the later Typhoon Rammasun.Combining data regarding the water level in the Xinfengjiang Reservoir and seismicity frequency changes in the Taiwan region during these two typhoon events,we suggest that typhoon activity may increase microseism energy by impacting fault stability around the Xinfengjiang Reservoir.Whether a fault can be activated also depends on how close the stress accumulation is to its failure point.

Fracture evolution and localization effect of damage in rock based on wave velocity imaging technology

By utilizing wave velocity imaging technology,the uniaxial multi-stage loading test was conducted on siltstone to attain wave velocity imagings during rock fracture.Based on the time series parameters of acoustic emissions(AE),joint response characteristics of the velocity field and AE during rock fracture were analyzed.Moreover,the localization effect of damage during rock fracture was explored by applying wave velocity imagings.The experimental result showed that the wave velocity imagings enable three-dimensional(3-D)visualization of the extent and spatial position of damage to the rock.A damaged zone has a low wave velocity and a zone where the low wave velocity is concentrated tends to correspond to a severely damaged zone.AE parameters and wave velocity imagings depict the changes in activity of cracks during rock fracture from temporal and spatial perspectives,respectively:the activity of cracks is strengthened,and the rate of AE events increases during rock fracture;correspondingly,the low-velocity zones are gradually aggregated and their area gradually increases.From the wave velocity imagings,the damaged zones in rock were divided into an initially damaged zone,a progressively damaged zone,and a fractured zone.During rock fracture,the progressively damaged zone and the fractured zone both develop around the initially damaged zone,showing a typical localization effect of the damage.By capturing the spatial development trends of the progressively damaged zone and fractured zone in wave velocity imagings,the development of microfractures can be predicted,exerting practical significance for determining the position of the main fracture.

Characteristics of gravity fields in the Jinggu M6. 6 earthquake

Based on the study of high-precision gravity data obtained from recent studies and the regional gravi- ty network for Yunnan province, a variation in the regional gravity field was identified before the occurrence of the Yunnan Jinggu M6.6 earthquake.

Spatial-temporal Evolution Analysis on Land Use Multifunctionality in the China-Vietnam Border Area

Exploring the spatial and temporal evolution characteristics of the border land use multifunctionality(LUMF)provides insights for taking advantage of border land use and optimizing border land use policies.Based on the improved Technique for Order Preference by Similarity to an Ideal Solution(TOPSIS)mode,this study identifies and evaluates the LUMFs in the China-Vietnam border area between 2000 and 2018 from the perspectives of agricultural production,social security,ecological service,landscape recreation,and national security.The results show that:1)The comprehensive land use functions in most counties and cities continued to be improved.2)The comprehensive land use function exhibits remarkable spatial divergence and aggregation characteristics.The high-value area of the agricultural production function and social security function evolves from the east to the west.In addition,the spatial evolution of ecological service function is complicated,without an obvious spatial divergence and aggregation pattern.The landscape recreation function shows different spatial differentiation characteristics in the early and middle stage,and forms a large cluster in the later stage.Finally,the spatial evolution pattern of the national security function is significant.3)Designing differentiated border land policies,improving border land use security,and establishing a long-term mechanism for ecological protection and ecological compensation can aid in optimizing the LUMF level in the border area.

Hydrodynamic Evolution and Hydrocarbon Accumulation in the Dabashan Foreland Thrust Belt,China

There are two plays in the Dabashan foreland tectonic belt： the upper and the lower plays. The lower play experienced one sedimentary hydrodynamic stage, two burial hydrodynamic stages, two tectonic hydrodynamic stages and two infiltration hydrodynamic stages from the Sinian to the Cenozoic, while the upper play had one sedimentary hydrodynamic stage, one burial hydrodynamic stage, two tectonic hydrodynamic stages and one infiltration hydrodynamic stage from the Permian to the Cenozoic. Extensive flows of both sedimentary water, including hydrocarbons, and deep mantle fluid occurred in the Chengkou faults during collision orogeny in the Middle-Late Triassic Indosinian orogeny, and fluid flow was complicated during intracontinental orogeny in the Middle-Late Jurassic. In addition to these movements, infiltration and movement of meteoric water took place in the Chengkou faults, whereas in the covering-strata decollement tectonic belt, extensive sedimentary water flow （including hydrocarbons） occurred mainly in the Zhenba and Pingba faults. During the stage of rapid uplift and exhumation from the Cretaceous to the Cenozoic, the fluid flow was characterized mainly by infiltration of meteoric water and gravity-induced flow caused by altitude difference, whereas sedimentary water flow caused by tectonic processes was relatively less significant. Sedimentary water flow was more significant to the lower play in hydrocarbon migration and accumulation during collision orogeny in the Middle-Late Triassic Indosinian orogeny, but its influence is relatively slight on the upper play. On one hand, hydrodynamics during intracontinental orogeny in the Middle-Late Jurassic adjusted, reformed or oven destroyed oil reservoirs in the lower play; on the other hand, it drove large amounts of hydrocarbons to migrate laterally and vertically and is favorable for hydrocarbon accumulation. Infiltration hydrodynamics mainly adjusted and destroyed oil reservoirs from the Cretaceous to the Cenozoic.

Mechanical and damage evolution properties of sandstone under triaxial compression

To study the mechanical and damage evolution properties of sandstone under triaxial compression, we analyzed the stress strain curve characteristics, deformation and strength properties, and failure process and characteristics of sandstone samples under different stress states. The experimental results reveal that peak strength, residual strength, elasticity modulus and deformation modulus increase linearly with confining pressure, and failure models transform from fragile failure under low confining pressure to ductility failure under high confining pressure. Macroscopic failure forms of samples under uniaxial compression were split failure parallel to the axis of samples, while macroscopic failure forms under uniaxial compression were shear failure, the shear failure angle of which decreased linearly with confin- ing pressure. There were significant volume dilatation properties in the loading process of sandstone under different confining pressures, and we analyzed the damage evolution properties of samples based on acoustic emission damage and volumetric dilatation damage, and established damage constitutive model, realizing the real-time Quantitative evaluation of samnles damage state in loading process.

Evolutionary characteristics and driving factors of carbon emission performance at the city level in China

To achieve carbon peak targets,realize carbon neutrality vision,and tackle global climate change,China must improve the carbon emission performance at the city level.Based on the carbon emission performance of 191 prefecture-level cities in China from 1997 to 2017,this paper analyses the evolution characteristics of urban carbon emission performance from three aspects:the overall spatial and temporal evolution,the differences according to both region and city size,and the differences among clusters categorized by carbon emission performance at the city level.This paper also reveals the impact of the social and economic transition on China’s carbon emission performance.The results show that:(1)The overall level of carbon emission performance of Chinese cities is low,and there is a downward trend during the study period.The differences in carbon emission performance among cities are convergent,but there is a wide gap between high and low values.(2)The carbon emission performance of cities in eastern coastal areas is higher than that in non-coastal areas cities.Large urban agglomerations and economically developed regions,such as provincial capitals,are the agglomeration areas of high urban carbon emission performance values.(3)The carbon emission performance level of cities with similar sizes will converge.At the same time,such changes will enhance the differences among carbon emission performances at the city level within the same region.(4)Cities that belong to high urban carbon emission performance clusters are mainly distributed in the eastern region.Such cities are classified into large cities,supercities,and megacities.Compared with low urban carbon emission performance clusters,cities in high urban carbon emission performance clusters show a higher proportion in the medium-high level and high level of carbon emission performance.Moreover,cities in high urban carbon emission performance clusters are more likely to improve their urban carbon emission performance.(5)The economic agglomeration effect,industrial structure adjustment and carbon intensity reduction have a significant impact on improving urban carbon emission performance.Population agglomeration has an incremental effect,and the anticipated benefits of environmental regulation have yet to be fully realized.The impacts of different clusters and different regions are variable.Finally,this paper advances policy enlightenment according to its research findings.

Impacts of precipitation variation and soil and water conservation measures on runoff and sediment yield in the Loess Plateau Gully Region, China

The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.

Characteristics and Causes of the Spatial Evolution of Urban Villages:A Case Study of Shenzhen Special Economic Zone

Studies on the renovation and governance of urban villages have become the interest of human geography since the 1990s.However up to now,there is little literature focusing on the development patterns and dynamic mechanism of the spatial evolution of urban villages based on the theoretical system of urban spatial structure,and there are few scholars doing analyses on the relationship between urban villages and general urban areas in terms of spatial development.In this paper,Shenzhen,the most representative city of China in terms of urban village development,is taken as a case for exploring the characteristics and modes of the spatial evolution of urban villages.With census data of urban village construction in 1999 and 2004 in terms of built-up area,floor area,and construction intensity,the spatial and temporal evolution of the 91 administrative urban villages in the original Shenzhen Special Economic Zone have been analyzed in comparison with that of Shenzhen's general urban areas.It is indicated that the spatial evolution of urban villages matches with the general rules of the spatial development of general urban areas in three aspects.First,land expansion is the most remarkable mode of spatial evolution in the early stage of development;second,in the period of rapid development,there is the obvious tendency of "distance-decay" in terms of construction intensity accompanied by some anomalous fluctuations at certain points;third,renewal and redevelopment are carried out gradually in the mature stage of development.However,because of historical and institutional restrictions,the spatial evolution of urban villages shows its unique characteristics in the aspects of original spatial distribution and spatial expansion mode in the period of rapid development,etc.The outcomes of this study would help not only enrich the theoretical study on the evolution mode of urban spatial structure,but also strengthen the administration over urban villages,in particular with the suggestions that the spatial evolution of urban villages as a type of urban space should not be the same as that of general urban areas and its unique characteristics should not be ignored;specific rules should be set up to guide the rational spatial evolution of urban villages according to the economic development of the city,as well as the housing demands of various kinds of residents.

Study on the Method of Short-Term Synthetic Earthquake Prediction in the North China Region

Based on the extraction and calculation of the short-term seismic precursory information magnitude from the 114 major precursory observations in the North China region, and together with consideration of factors such as geological structure, seismicity, crustal thickness, and in particular, the current geodynamics of the region, the authors studied the time-space evolution characteristics of the short-term earthquake precursory information magnitude and its relationship with earthquakes and proposed the index and method for the short-term synthetic prediction of earthquakes with M S≥5.0 in the North China region. The inspection through R-value shows that the method is effective to a certain extent for earthquake prediction.

Physical and mechanical properties of sandstone containing a single fissure after exposure to high temperatures

In order to investigate the physical and mechanical properties of sandstone containing fissures after exposure to high temperatures,fissures with different angles α were prefabricated in the plate sandstone samples,and the processed samples were then heated at 5 different temperatures.Indoor uniaxial compression was conducted to analyze the change rules of physical properties of sandstone after exposure to high temperature,and the deformation,strength and failure characteristics of sandstone containing fissures.The results show that,with increasing temperature,the volume of sandstone increases gradually while the quality and density decrease gradually,and the color of sandstone remains basically unchanged while the brightness increases markedly when the temperature is higher than 585 ℃;the peak strength of sandstone containing fissures first decreases then increases when the temperature is between 25℃and 400℃.The peak strain of sandstone containing fissures increases gradually while the average modulus decreases gradually with increasing temperature,and the mechanical properties of sandstone show obvious deterioration after 400 ℃.The peak strain of sandstone containing fissures increases gradually while the average modulus decreases gradually with increasing temperature;with increasing angle αof the fissure,the evolution characteristics of the macro-mechanical parameters of sandstone are closely related to the their own mechanical properties.When the temperature is 800 ℃,the correlation between the peak strength and average modulus of sandstone and the angle α of the fissure is obviously weakened.The failure modes of sandstone containing fissures after high temperature exposure are of three different kinds including:tensile crack failure,tensile and shear cracks mixed failure,and shear crack failure.Tensile and shear crack mixed failure occur mainly at low temperatures and small angles;tensile crack failure occurs at high temperatures and large angles.

Evolution of surface morphology and photoluminescence characteristics of 1.3-μm In_(0.5)Ga_(0.5)As/GaAs quantum dots grown by molecular beam epitaxy

Evolution of surface morphology and optical characteristics of 1.3-μm In0.5Ga0.5As/GaAs quantum dots （QDs） grown by molecular beam epitaxy （MBE） are investigated by atomic force microscopy （AFM） and photoluminescence （PL）. After deposition of 16 monolayers （ML） of In0.5Ga0.5As, QDs are formed and elongated along the [120] direction when using sub-ML depositions, while large size InGaAs QDs with better uniformity are formed when using ML or super-ML depositions. It is also found that the larger size QDs show enhanced PL efficiency without optical nonlinearity, which is in contrast to the elongated QDs.

The effect of volatile components in oil on evolutionary character- istics of diamondoids during oil thermal pyrolysis

On the basis of the results of simulation experiments, now we better understand the contribution of high carbon number hydrocarbons to diamondoid generation during thermal pyrolysis of crude oil and its sub-fractions(saturated, aromatic, resin, and asphalene fractions). However, little is known about the effect of volatile components in oil on diamondoid generation and diamondoid indices due to the lack of attention to these components in experiments. In this study, the effect of volatile components in oil on diamondoid generation and maturity indices was investigated by the pyrolysis simulation experiments on a normal crude oil from the HD23 well of the Tarim Basin and its residual oil after artificial volatilization, combined with quantitative analysis of diamondoids. The results indicate that the volatile components(≤n C12) in oil have an obvious contribution to the generation of adamantanes, which occurs mainly in the early stage of oil cracking(Easy Ro<1.0%), and influences the variations in maturity indices of adamantanes; but they have no obvious effect on the generation and maturity indices of diamantanes. Therefore, some secondary alterations e.g., migration, gas washing, and biodegradation, which may result in the loss of light hydrocarbons in oil under actual geological conditions, could affect the identification of adamantanes generated during the late-stage cracking of crude oil, and further influence the practical application of adamantane indices.

Thermodynamic Characteristic and Phase Evolution in Immiscible Cr–Mo Binary Alloys

This paper systematically reports the thermodynamic characteristic and phase evolution of immiscible Cr–Mo binary alloy during mechanical alloying（MA） process. The Cr–35Mo（in at%） powder mixture was milled at 243 and258 K, respectively, for different time. For comparative study, Cr–15Mo and Cr–62Mo powder mixtures were milled at 243 K for 18 h. Solid solution Cr（Mo） with body-centered cubic（bcc） crystal structure and amorphous Cr（Mo） alloy was obtained during MA process caused by high-energy ball milling. Based on the Miedema＇s model, the free-energy change for forming either a solid solution or an amorphous in Cr–Mo alloy system is positive but small at a temperature range between 200 and 300 K. The thermodynamical barrier for forming alloy in Cr–Mo system can be overcome when MA occurs at 243 K, and the supersaturated solid solution crystal nuclei with bcc structure form continually, and three supersaturated solid solutions of Cr–62Mo, Cr–35Mo and Cr–15Mo formed. Milling the Cr–35Mo powder mixture at 258 K, the solid solution Cr（Mo） forms firstly, and then the solid solution Cr（Mo） transforms into the amorphous Cr（Mo）alloy with a few of nanocrystallines when milling is prolonged. At higher milling temperature, it is favorable for the formation of the amorphous phase, as indicated by the thermodynamical calculation for immiscible Cr–Mo alloy system.

A Special MJO Event with a Double Kelvin Wave Structure

The second Madden–Julian Oscillation（MJO）event during the field campaign of the Dynamics of the MJO/Cooperative Indian Ocean Experiment on Intraseasonal Variability in the Year 2011（DYNAMO/CINDY2011）exhibi ted an unusual double rainband structure.Using a wavenumber-frequency spectral filtering method,we unveil that this double rainband structure arises primarily from the Kelvin wave component.The zonal phase speed of the double rainbands is about 7.9 degree per day in the equatorial Indian Ocean,being in the range of convectively coupled Kelvin wave phase speeds.The convection and circulation anomalies associated with the Kelvin wave component are characterized by two anomalous convective cells,with low-level westerly（easterly）and high（low）pressure anomalies to the west（east）of the convective centers,and opposite wind and pressure anomalies in the upper troposphere.Such a zonal wind–pressure phase relationship is consistent with the equatorial free-wave dynamics.While the freeatmospheric circulation was dominated by the first baroclinic mode vertical structure,moisture and vertical motion in the boundary layer led the convection.The convection and circulation structures derived based on the conventional MJO filter show a different characteristic.For example,the phase speed is slower（about 5.9 degree per day）,and there were no double convective branches.This suggests that MJO generally involves multi-scales and it is incomplete to extract its signals by using the conventional filtering technique.