基于三度分析的环渤海区域旅游产业发展水平研究

系统研究区域旅游产业分析评价方法基础上,结合产业经济和区域分析理论,提出"三度"分析框架,阐明了优势度、成长度、成熟度的理论模型与计算方法。分析框架分别从旅游产业的区域产业地位、产业经济增长、结构绩效优劣角度对区域旅游产业进行综合评价。结合环渤海区域案例,综合分析与评价了环渤海区域旅游产业发展水平,发现环渤海区域旅游产业整体上优势度、成长度高,而成熟度不高。同时环渤海区域内旅游产业发展水平差异明显,说明分别处于不同的发展阶段,优势度度量了其现状产业地位,成长度表征了其近年的增长性。环渤海区域内各地区的共性是旅游产业发展的结构性矛盾十分突出。最后,提出了优化旅游产业结构等环渤海区域旅游发展的若干对策建议。

全面理解新时代中国社会主要矛盾变化的三重维度

党的十九大报告明确提出了新时代中国社会主要矛盾的变化,这是以习近平同志为核心的党中央基于我国进入新的历史方位而作出的重大战略判断。全面理解新时代中国社会主要矛盾的变化,需要从理论、现实和价值三个维度进行分析。从理论维度分析,我们找到了中国社会主要矛盾变与不变的理论根源;从现实维度分析,生产力的发展是新时代社会主要矛盾变化的必然条件;从价值维度分析,新时代确立了"以人民为中心"的价值追求。

Accurate estimation of soil shear strength parameters

The cost and safety of geotechnical engineering are highly depending on the accuracy of soil shear strength parameters.There are three methods often used to estimate soil shear strength parameters,i.e.,moment method,3-sigma rule and linear regression method.In this study,the accuracy of these three methods is compared.Traditional linear regression method(LRM)can only offer the mean of shear strength parameters.Some engineers misuse the standard error of shear strength indexes as the standard deviations.Such misuse may highly underestimate the uncertainty and induce high risk to the geotechnical design.A modified LRM is proposed to determine both the mean and variance of shear strength parameters.The moment method,three-sigma rule and LRM are used to analyze the tri-axial test data in Xiaolangdi Hydraulic Project and three numerical shear strength tests.The results demonstrate that:1)The modified LRM can offer the most accurate estimation to shear strength parameters;2)A dimensionless formula is much preferred in LRM rather than a dimensional formula.The stress ratio formula is much better than stress relation in the shear strength parameter analysis.The proposed method is applicable to shear strength parameter analysis for tri-axial test data,direct shear test and the un-drained shear strength test of stratified clay.

Design and optimization of vector coil sensor suited to magnetometric resistivity method

Magnetometric resistivity(MMR)method is a new way to detect dam leakage.The coil sensor is generally used to collect data in geophysical exploration methods.Given the characteristics of accurate vector data requirements and high sensitivity requirement,a three-component MMR air-core coil sensor is designed.Through the analysis of sensor sensitivity and coil structure parameters,the coil structure and turn number are designed.By analyzing the noise source of the sensor,a suitable amplifier is selected to reduce the background noise of the system.Through the analysis of the three-component non-orthogonal angles,the parameters of the non-orthogonal angles of the coils are corrected.Finally,a three-component MMR induction magnetic field sensor is designed.The volume of the sensor is controlled at 0.027 m 3.The background noise of X、Y and Z are 5.030435 nV/Hz@380 Hz and magnetic field sensitivities are 0.18995 pT/Hz@380 Hz.The three channels have good consistency,and the three-component nonorthogonal angles correction error of three components is controlled within 0.2%.

Stress analysis of single joint rock mass under triaxial compression

Based on the fundamental principle of rock mechanics, the stresses of single joint rock mass under three-dimensional compression were analyzed. The effect of the in-termediate principle stress on the strength of single joint rock mass were discussed in par-ticular. It is found that the strength of single joint rock are affected by the intermediate principal stress, which may be the main factor in some conditions.

Dynamic Characteristic of the Medium Span Concrete Footbridges

Concrete footbridges, due to their mass, stiffness and damping, are perceived as strucaires more resistant to vibration caused by dynamic action of the users. In order to verify the dynamic behaviour of concrete footbridges, a series of field tests and numerical analyses have been carried out. In the paper, the results of the dynamic field tests of three medium span concrete footbridges with different structural systems （frame, beam and arch footbridges） and their dynamic characteristics （mass, stiffness and damping） are presented. The field tests were carried out for different types of vibration excitation caused by walking, running and jumping persons. Furthermore, the vibrational comfort criteria for footbridges are shortly described and verified for examined structures. The study were supplemented by numerical calculation of natural mode shapes and frequencies of the structures using the 3D FEA （finite element analysis） models with elastic supports elements in order to ensure the compatibility of the calculated and measured mode shapes of the footbridges.

Vulnerability to Flood in the Vietnamese Mekong Delta： Mapping and Uncertainty Assessment

The Vietnamese Mekong Delta is located at the end of the Mekong River, one of the 10 largest rivers in the world. It plays an important role, especially in terms of food security for not only Vietnam but also the world. However, the Vietnamese Mekong Delta is projected to be heavily affected by： （1） the annual （fluvial） flood, which would be changed in terms of time and spatial distribution after impacts of climate change scenarios （i.e., sharper hydrograph with shorter flood period）; and （2） sea level rise. Such combination would result in significant changes of surface water resources, leading to consequent impacts on the existing fanning systems in the Vietnamese Mekong Delta. Therefore, this paper presents a new approach of integrating a one-dimensional hydrodynamic model （ISIS-1 D） with GIS （Geographic Information System ） analyses to： （1） identify priority areas for flood adaptation and mitigation; （2） provide an insight to local decision-makers in the Vietnamese Mekong Delta in changes of future floods.

Thermal analysis of high speed permanent magnetic generator

High-speed permanent magnetic generators (HSPMG) are common and important power generation equipments used in distributed generation systems. A 100 kW level HSPMG is investigated in this paper, and it is fluid-thermal coupling analyzed. The transient 2D electromagnetic field while machine is under rated operating is analyzed by using the time-stepping FEM, from which the electromagnetic performances and the loss distributions are obtained. Then, an analysis model for fluid-solid temperature field analysis is established. Taking losses as the distributed heat sources, the 3D thermal field is coupling calculated. The variations of heat transfer coefficient and temperature of fluid in stator grooves along the axial direction, as well as the whole region 3D temperature distribution in HSPMG are obtained. Then, considering the variations of heat sources distributions and heat transfer conditions, 3D temperature fields of HSPMG operating under different speeds are calculated, and the influences of machine operating speed on the HSPMG thermal performance are studied, based on which, the functions of machine temperature with operating speed and stator windings resistance are proposed. The obtained conclusions may provide a useful reference for the design and research of HSPMG.

Mechanism study of the transmission of moxibustion heat in human acupoint tissues

Objective: To discuss the topical action characteristics of the biological transmission of moxibustion heat via temperature collection and numerical modeling. Methods: Temperature of moxibustion was measured at multiple points at a distance of 3 cm to obtain the moxibustion temperature field nephograms by the high-accuracy temperature measure array. Finite element analysis was used to imitate the three-dimensional dynamic distribution of temperature in acupoint tissues. Results: Through numerical analysis, the one-dimensional, two-dimensional and three-dimensional distributions of temperature in human acupoint tissues at 5 min of moxibustion were established. The result showed that moxibustion heat mainly tran smitted from the surface of the tissue to the internal, and the in flue nee of moxibusti on heat decreased with the depth of the tissue. The analysis of the nephograms of acupoint tissue temperature at 5,10, 15 and 20 min of moxibustion showed that with the in crease of the moxibusti on time, the temperature in acupoint tissues consta ntly rose, and the transmission depth of moxibustion heat also further expanded inside acupoint. Conclusion: By establishing the three-dimensional dynamic model of heat transmission inside acupoint tissues with the biological parameters of human tissues and the temperature values obtained, this study used finite element analysis software ANSYS 14.0 and discovered the rules in the transmission of heat in body tissues during moxibustion, and the features in moxibustion heat transmission (from the proximal to the distant) and heat penetration (from the surface to the intern al). This study provides theoretical and experime ntal support for the application of moxibusti on in clinical practice.

Effects of overburden, rock strength and pillar width on the safety of a three-parallel-hole tunnel

During the excavation of three-parallel-hole tunnel, the tunnel might collapse due to over-stress as a result of inadequate rock pillar width. Treating the rock overburden depth, rock strength, and rock pillar width as variables, a series of 3D numerical analysis was carried out to examine the effect of each variable on the safety of the tunnel, in particular the rock pillar. A stress strength ratio (SSR) was used to define whether the safety of the rock pillar was exceeded. A simple design chart for the case of three-parallel-hole tunnel, which took into account the influence of overburden depth, rock pillar width, and rock strength, was also proposed for used in the preliminary design stage.

Multi-scale chemo-mechanical analysis of the slip surface of landslides in the Three Gorges, China

Multi-scale chemo-mechanical effects and microscopic failure modes are explored in the evolution of strength change of slip surface. Direct shear equipments, scanning electro-microscope and X-ray diffraction are used to trace the change in strength of remodeled soils of slip surfaces in the Three Gorges area. Results show that there is a release of alkali metals and concentration of clay minerals on the surface. During the tests, potassium ions were released, the cementation was reduced, and the ratio of interlayer minerals varied associated with strength change. Accordingly, illites or montmorillonite-illite mixtures turned into montmorillonite. So the strength change originates from the release of alkali metal ions on molecular scale that leads to the concentration and transition of clay minerals on meso-scale. The evolution of slip surface and soil strength is a typical process involving multi-scale processes of structure changes and chemo-mechanical coupling.