改进的RSS信息推送技术在农地流转中的应用

我国农地流转过程存在双方沟通不畅、信息不对称等问题,建立合理有效的信息沟通机制是解决当前农地生产要素合理流动和优化配置的有效途径之一。本文在分析农地流转信息推送特征的基础上,提出将RSS信息技术应用到农地流转信息推送领域,并探讨在RSS信息推送模型中引入地名匹配步骤,进一步提高农地流转信息推送的查全率、查准率和综合分类率。     

自主车的运动仿真

在自主车的运动路径规划中,局部路径规划特别重要,而且是自主车的一项关键技术。该文提出了将自主式多智能体的任务和反应性行为模型嵌入到离散事件系统框架中作局部路径规划的方法,此方法克服了势场法（包括早期的虚力场法）的缺陷,为确保自主车运动路径规划的可靠性和合理性,该文就局部路径规划对自主车作运动仿真。     

Study on destructions and reinforcement measures of mined constructions

Ground movement and deformation caused by underground mining would destroy the constructions located within subsidence area. Constructions would suffer different destructions with different location. The effect of ground deformation caused by underground mining to constructions was analyzed. Analyzed the destructive types of constructions in different ground movement and deformation. Taking a two-storey building for example, the walls were reinforced by computation before mining. To protect the construction the reinforcement measures to the construction before mining were studied.     

Study on calculation method of surface subsidence about the dewatering concretion of clay influenced by mining

Under the condition of thick alluvia, there is biggish declination in predicting the coal mining subsidence by commonly strip design method compared with the practical observation, the sinkage is much smaller. Based on the method of the probability integral about coal mining subsidence calculation, discussed the surface subsidence calculation and deduced the formulas caused by the clay with dewatering. The results show that the clay dewatering has great impact on surface subsidence. Therefore, the clay dewatering on surface subsidence should not be overlooked.     

Breakability analysis of the elastic rock beam based on the winkler model

Based on the Winkler model, a mechanic model was established with formulas derived concerned with the deformations before and after a roof breakage at places in front of and at the back of the working face. In accordance with the theory for rock beam breakage, the beam breaking position in front of the working face is specified. In addition, the formulas were developed for the velocity of the subsidence at observatory point A in front of the working face when the coal wall serves as the coordinate center and the advance distance at time t as the dynamic coordinate. In the application of the above-mentioned achievements to the practice of Xieqiao Mine and the mines of the Eastern Panji Company of Huainan Mining（Group） Co. Ltd., the results concerned with the velocity with which the roof stratum tends to subside before and after breakage as derived from the mechanic model are well compatible to the results based on in-situ observations and measurements.     

改进Kriging插值的地面沉降监控模型的研究

随着城市化进程的加快,地下水超采、高层建筑的兴建、建筑容积率和建筑密度的增加以及特殊的地质环境所引起的城市地面沉降日趋严峻。因此,建立一种通用性更强、效率更高的沉降监控模型是十分必要的。Kriging插值以其独特的建模机制,在区域空间插值中已得到广泛应用,而在时域插值中却鲜有研究,借鉴Kriging空间插值模型,研究其在时间域插值的应用具有重要意义。为保证时域模型数据的时间相关性,减少扰动信息累积,需删除早期数据;而为了保证变异函数能真实反映数据的时间分布特征,模型又需要足够的样本数据。为此,探讨了一种基于灰色理论的等维动态Kriging时域插值模型,采用等维动态预测,保证数据时间相关性,减少信息扰动;采用对建模数据量要求较少的灰理论模型来拟合变异函数曲线,解决样本不足的问题,并结合工程实例,验证了该算法的实用性、可靠性和有效性。更多还原     

Effects of land use and changes in cover on the transformation and transportation of iron:A case study of the Sanjiang Plain,Northeast China

Wetland reclamation has been ongoing in the Sanjiang Plain since the mid-1950s,which has resulted in major changes in wetlands and the agriculture ecosystem in the region that have influenced the iron output to the Sea of Okhotsk and limited the primary productivity in the North Pacific Ocean.This study was conducted to investigate the chemical forms of iron in different aquatic environments(agricultural water including groundwater,paddy water,and canal water;wetland water including marsh water,marsh stream...     

Electromyography applied to sport ergonomics

Abstract

The improvement of electromyographic (EMG) devices for the detection of electric potentials produced in voluntary complex movements and the evolution of methodological approaches to data acquisition and computerized analysis of patterns, are responsible for the increased applications of EMG in bioengineering, rehabilitation, sport and occupational biomechanics, physiology and zoology and to a lesser extent in ergonomics. This paper describes three different EMG applications related to a sport environment using three different EMG registration and data acquisition approaches.

The first study examined the relation between the swimming action in water and its simulation using training equipment on land. It was found that with respect to the mechanical aspects of dry-land equipment and to the biomechanical differences in the execution of the front crawl action on dry land and in water, based on EMG activity of the propulsion muscles, the best results were found when using devices with accommodating resistance. Recovery muscles were best imitated using isokinetics, but despite the greater effort on land, lower EMG activity was recorded than in water. It was generally observed that whenever the swimmer acted against a mechanical resistance an important pattern deviation was noted.

Second, a study to determine the influence of ski materials on the EMG muscle activity of skiers showed systematic differences between the use of racing, soft and compact skis. The results supported the idea that the soft ski should be more highly recommended than the compact or racing ski for both general and competive use.

Finally, in a third study we found that there was a very high degree of similarity in the pattern and intensity of muscle activity in both free swimming and swimming against a mechanical resistance (MAD swimming), even though the kinesiological aspects of the movement trajectory were proved different beforehand.     

Desorption kinetics of trichloroethylene and perchloroethylene from aged dense nonaqueous phase liquid-contaminated soil

Batch experiments were conducted to investigate the desorption kinetics of a contaminated soil collected from a field site at Hill Air Force Base (AFB), Utah. The site has been contaminated with many dense nonaqueous phase liquids (DNAPLs), primarily trichloroethylene (TCE) and perchloroethylene (PCE), for more than 60 years. Similar desorptive behaviour of both TCE and PCE was observed: a stage of fast release of the contaminant at the start followed by a very slow stage. Moreover, it is suggested that not all the contaminant in the solid phase may be released to the aqueous phase, apparently due to the age factor. Local variations were observed in the effective diffusivity and other sorption-related parameters across the site due to aquifer heterogeneity. Experimental results were then simulated using a numerical code based on the intraparticle diffusion model. Good agreement was found between both results.     

隐退的岗丘(一)

本文从一张大连的旧照片说起,通过描绘和分析人们对于高差与坡度的感觉改变,讲述了在大连城市开发中自然地貌特征的逐渐隐退。