Optimum location of surface wells for remote pressure relief coalbed methane drainage in mining areas

Based on engineering tests in the Huainan coal mining area,we studied alternative well location to improve the performance of surface wells for remote pressure relief of coalbed methane in mining areas.The key factors,affecting location and well gas production were analyzed by simulation tests for similar material.The exploitation results indicate that wells located in various positions on panels could achieve relatively better gas production in regions with thin Cenozoic layers,low mining heights and slow rate of longwall advancement,but their periods of gas production lasted less than 230 days,as opposed to wells in regions with thick Cenozoic layers,greater mining heights and fast rates of longwall advancement.Wells near panel margins achieved relatively better gas production and lasted longer than centerline wells.The rules of development of mining fractures in strata over panels control gas production of surface wells.Mining fractures located in areas determined by lines of compaction and the effect of mining are well developed and can be maintained for long periods of time.Placing the well at the end of panels and on the updip return airway side of panels,determined by lines of compaction and the effect of mining,would result in surface wells for remote pressure relief CBM obtaining their longest gas production periods and highest cumulative gas production.

Acoustic emission source location method and experimental verification for structures containing unknown empty areas

Acoustic emission(AE)localization plays an important role in the prediction and control of potential hazardous sources in complex structures.However,existing location methods have less discussion on the presence of unknown empty areas.This paper proposes an AE source location method for structures containing unknown empty areas(SUEA).Firstly,this method identifies the shape,size,and location of empty areas in the unknown region by exciting the active AE sources and using the collected AE arrivals.Then,the unknown AE source can be located considering the identified empty areas.The lead break experiments were performed to verify the effectiveness and accuracy of the proposed method.Five specimens were selected containing empty areas with different positions,shapes,and sizes.Results show the average location accuracy of the SUEA increased by 78%compared to the results of the existing method.It can provide a more accurate solution for locating AE sources in complex structures containing unknown empty areas such as tunnels,bridges,railroads,and caves in practical engineering.

Method of Fault Area ＆ Section Location for Non-solidly Earthed Distribution System

中国中压配电网以架空线为主，多为小电流系统，单相接地故障占到电网故障总数的80％以上，但中国配网自动化系统基本上没有小电流接地故障定位功能，使配网自动化系统在提高可靠性的作用上大打折扣。给出一种小电流接地故障区段定位新方法，在线路上配置广域相量测量固定测点，获取小电流电网单相接地故障特征信息。基于测点相邻矩阵区段起始测点标识向量和故障路径标识向量概念，提出确定故障区间边界节点算法。物理模拟实验和挂网测试表明：该故障分区分段定位方法能够在线求解小电流接地故障段边界节点，缩小线路维护巡视范围。确定故障区间边界节点算法还可用于确定故障区相关负荷开关，为线路维护和馈线自动化提供依据。

AN APPROACH TO RETAIL COMMERCE LOCATION OF GUANGZHOU URBAN AREA

Proceeding from the commercial function of Guangzhou urban area, this paper expounds the principles and requirements for choosing commercial location, puts forward the bases to determine the limits of commercial centres. Thirty major commercial centres, in Guangzhou urban area are classified by means of cluster analysis. The function, size, hierarchy and interconnection of commercial centres of different groups are studied. The paper emphatically analyzes the major characteristics and formation factors of the commercial location of Guangzhou urban area. Finally, to counter some problems in existence, some suggestions are put forward in order to improve the commercial location of Guangzhou urban area.

The Incorporation of Precautionary Principle in the Planning of Global System for Mobile Communications Mast Locations in Built-up Areas： Proposals for Jimeta, Nigeria

This paper aimed at incorporating the precautionary principles into the planning and development of GSM （global system for mobile communications） masts within the built-up areas of Jimeta. Using GIS （geographic information system） analysis technique, the zone of precautionary principle was defined to 500 meters radius as the zone within which precautionary measures are exercised. The criteria for siting GSM base station are also equally identified. For instance, the presence of certain elements within the precautionary zone like schools, hospitals, residential density and overlap of RF （radio frequency） occurrences, may disqualify any mast location. Analysis of the land use within precautionary zone has shown various proportions of exposure to RF, whereas, only 3.39% of the masts are suitably located and 94.92% are not and therefore should be relocated. The study recommend measures for addressing physical development within precautionary areas, including land conversion and mast sharing to reduce potential harmful effects of RF emanating from GSM base stations.

Numerical analysis of stability for mined-out area in multi-field coupling

There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.

Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area

Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area was carried out with FLAC3D. The whole analytical process was divided into two steps, including the static analysis and the dynamic analysis which were used to simulate the influence of excavation process and blasting vibration respectively. The results show that the shape of right upper boundary is extremely irregular after excavation, and stress concentration occurs at many places and higher tensile stress appears. The maximum tensile stress is higher than the tensile strength of rock mass, and surrounding rock of right roof will be damaged with tension fracture. The maximum displacement of surrounding rock is 4.75 mm after excavation. However, the maximum displacement increases to 5.47 mm after the blasting dynamic load is applied. And the covering area of plastic zones expands obviously, especially at the foot of right upper slope. The analytical results are in basic accordance with the observed results on the whole. Damage and disturbance on surrounding rock to some degree are caused by excavation, while blasting dynamic load increases the possibility of occurrence of dynamic instability and destruction further. So the effective supporting and vibration reducing measures should be taken during mining.

Exploring Location Pattern of Commercial Stores in Shichahai, Beijing from a Street Centrality Perspective

The location pattern of different commercial stores in Shichahai, a historic conservation area in Beijing, was investigated from a street centrality perspective. Many previous studies have investigated the relationship between street centrality and land use patterns or commercial activities at interurban or intraurban scales. We considered Shichahai in this study to determine if street centrality applied at the street scale and if the street network was the only factor influencing the selection of store location. First, the nearest neighbor index, nearest neighbor hierarchical spatial cluster(NNHSC), and kernel density estimation(KDE) methods were used to provide baseline spatial distributions of commercial stores. Second, urban network analysis(UNA) tools were used to measure the street centrality indices under two conditions, with and without the weighting of cultural relics calculated by a principal component analysis(PCA). Finally, both store locations and centrality values at nodes were transformed to one unit(raster pixel) for a correlation analysis.The results showed that three of the four store types were clustered and had their own hotspots that were mostly located in the eastern and central parts of city blocks. The most momentous findings were determined from the street centrality indices. Among the three store types with correlation coefficients above 0.5, all centrality indices with landmark weighting, except straightness, had higher correlations,with closeness with landmark weighting having the highest correlation, followed by betweenness with landmark weighting. Therefore,we statistically concluded that street centrality could apply at the street scale and that the street network was not the only factor that influenced store location pattern, with landmarks also playing a significant role. The results provide guidance in determining the selection strategy for stores in a historic conservation area.

Instability identification on large scale underground mined-out area in the metal mine based on the improved FRBFNN

To identify the instability on large scale underground mined-out area in the metal mine effectively,the parameters of radial basis function were determined through clustering method and the improved fuzzy radial basis function neural network(FRBFNN)model of instability identification model about large scale underground mined-out area in the metal mine was built.The improved FRBFNN model was trained and tested.The results show that the improved FRBFNN model has high training accuracy and generalization ability.Parameters such as pillar area ratio,filling level and the value of rock quality designation have strong influence on instability of large scale underground mined-out area.Correctness of analysis about the improved FRBFNN model was proved by the practical application results about instability discrimination of surrounding rock in large-scale underground mined-out area of a metal mine in south China.

Quantitative analysis of biotechnical reinforcement for a steep slope consisting of composite coal-gangue-soil medium adjacent to a mined-out area

The engineering and geological characteristics of a steep slope consisting of coal gangue, rock and soil medium in Huating coal mine have been comprehensively investigated. Owing to humid weather, heavy rainfall, vegetation and porous characteristics of the soil and rock mass, the steep slope will be destabilized and induce mud-rock flow or derive hazard easily. Firstly, based on the classical slope reinforcement theory, some regularity between the shear and displacement in the destabilized zone of the slope with or without root strength contribution is presented. Then, based on the experimental and statistical analysis of root strength, hydrological characteristics and stability status, etc., some possible biotechnical techniques for reinforcement of the steep slope have been suggested. These methods are important for quantitative analysis of destabilization of the slope and design of the biotechnical reinforcement.

Time function of surface subsidence based on Harris model in mined-out area

The surface subsidence is a common environmental hazard in mined-out area. Based on careful analysis of the regularity of surface subsidence in mined-out area, we proposed a new time function based on Harris curve model in consideration of the shortage of current surface subsidence time functions. By analyzing the characteristics of the new time function, we found that it could meet the dynamic process, the velocity change process and the acceleration change process during surface subsidence. Then its rationality had been verified through project cases. The results show that the proposed time function model can give a good reflection of the regularity of surface subsidence in mined-out area and can accurately predict surface subsidence. And the prediction data of the model are a little greater than measured data on condition of proper measured data quantity, which is safety in the engineering. This model provides a new method for the analysis of surface subsidence in mined-out area and reference for future prediction, and it is valuable to engineering application.

Radio map updated method based on subscriber locations in indoor WLAN localization

With the rapid development of wireless local area network （WLAN） technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to overcome signal time-varying. A novel fingerprint positioning algorithm, known as the adaptive radio map with updated method based on hidden Markov model （HMM）, is proposed. It is shown that by using a collection of user traces that can be cheaply obtained, the proposed algorithm can take advantage of these data to update the labeled calibration data to further improve the position estimation accuracy. This algorithm is a combination of machine learning, information gain theory and fingerprinting. By collecting data and testing the algorithm in a realistic indoor WLAN environment, the experiment results indicate that, compared with the widely used K nearest neighbor algorithm, the proposed algorithm can improve the positioning accuracy while greatly reduce the calibration effort.

ANALYSIS OF EFFECT OF APOPLECTIC HEMIPLEGIA TREATED BY NEEDLING AROUND THE PROJECTIVE AREA ON THE SCALP OF FOCUS LOCATED WITH NUCLEAR MAGNETIC RESONANCE(NMR)

Sixty-one patients of ischemic apoplectic hemiplegia were randomly divided into group ofneedling around the ipsilateral projective area on the scalp of the fOcus (group A) and group of scalpacupuncture (group B). After 30 treatments, there is a significant difference between the therapeuticeffects of two groups (P < 0. 05 ), the former is better than the latter. It suggests that the method ofneedling around the projective area on the scalp of the focus is an effective and a feasible

The location analysis of real estate project development

Under the new situation of the macroscopic readjustment and control of the housing policy as well as the transformation of individual consumption ideas, this article has carded on the analysis on the housing location theory and its impact factors, and then emphatically pointed out the important impact of the housing location factors in the development of real estate project on urban development area and the built-up area＇s construction according to the theory, and it is expected that the developer of real estate project may benefit from the new background.

云南盐津地区两种地震序列的地震活动性分析

2020年9月—2021年1月,云南盐津地区出现了密集中小地震活动。为获取更完备的地震目录和更准确的震源参数,利用2020年1月—2021年2月云南及其邻区地震台网记录到地震事件的观测报告和连续波形,采用匹配定位方法检测到了1340次地震事件。利用联合波形互相关的双差地震定位方法进行重定位,获得了检测目录中351次地震的精确位置,对精定位后的地震活动时空分布特征进行分析研究,结果表明:盐津地区发生的密集中小地震活动为先后发生的2种不同类型的地震序列,沿两条不同走向和倾角的断裂分布,其中2020年9—10月的M_(L)3.9震群型地震序列发生在NNW走向、倾角约为75°的盐津—筠连断裂;2021年1月的M_(L)5.2孤立型地震序列发生在近SN走向、断层线与盐津—筠连断裂呈约30°夹角且倾角约为50°的隐伏断裂。

基于综合优属度的大风区高速铁路线路方案优选研究

为了应对西部路网扩张过程中必须面临的大风环境高铁建造问题,从问题的本源出发,研究选线设计与大风环境的耦合关系,建立科学的决策模型成为实现高速铁路高质量建设的关键内容。通过分析大风区高速铁路线路方案设计的主要影响因素并参考选线原则,从工程技术、生态环境、防风工程和社会效益4个方面选取22项指标,建立大风区高速铁路线路方案优选的多层次指标体系。采用三角模糊数对定性指标量化后,引入最佳去模糊性能值的方法将其转化为精确数,并融合粗糙集理论中的属性约简算法与信息熵理论,根据属性重要度将冗余或不重要的属性去除,实现初选指标的筛选。为使结果既能反映决策者的主观经验,又能反映指标数据的客观真实性,同时兼顾数据的变异和相互影响程度,分别采用G2法和CRITIC法进行主、客观赋权,并引入最优卡方距离的思想计算最终权重。最后,统筹考虑距离相似性和几何相似性维度,采用靶心距确定距离优属度以及与集合曲线趋势变化的趋同程度确定几何优属度,建立基于综合优属度的大风区高速铁路线路方案决策模型,并结合工程实例对模型进行验证。结果表明,基于本模型的大风区高速铁路方案的决策结果与工程实际具有较好的一致性,验证了模型的可靠性和适用性,为大风区高铁线路方案优化设计提供一定的理论支持。

1949—2021年登陆我国热带气旋历史规律研究

基于1949—2021年中国气象局最佳热带气旋路径数据,按照相应规则筛选出登陆我国的热带气旋及登陆位置,分析研究登陆热带气旋的数量、强度、时间等特征和变化规律,并具体分析沿海各地区登陆热带气旋的变化规律。结果表明:1949—2021年登陆我国的热带气旋数量呈略微减小趋势,有明显的高峰、低谷期,2018年后处于一个较低的水平;热带气旋登陆时的强度主要集中于强热带风暴、台风级别,登陆月份主要集中于7—9月;1949—2021年登陆我国的低强度热带气旋有减小趋势,而高强度热带气旋有增大趋势,说明登陆的高强度热带气旋将会越来越多,这可能与全球变暖以及热带扩展有关;1949—2021年登陆热带气旋位置在纬向上有轻微的南落,经向上无明显变化,这和前人的研究结论不一致,可能是由于选取的数据源以及时间跨度不一致造成的;我国沿海各地区热带气旋登陆频次最高的是广东地区,其次是台湾地区、海南、福建地区,大体上从南到北逐渐减少;台湾地区高强度登陆热带气旋占比最多,其次为浙江、福建、广东、海南地区;长期来看,广东、台湾地区年热带气旋登陆频次呈现减小趋势,浙江、福建地区呈现上升趋势。

基于BANs的通信及定位仿真实验平台

近年来,BANs在医学检测、监测和急救等领域被广泛应用,因此BANs对医学传感器的通信和定位系统的性能也提出了更高的要求,但利用实际设备直接在体内实验的不便,给WBAN中实现实时性能的测试和定位带来极大的困难,因此,开发了一个实时的性能测试硬件平台,用于BANs的通信和定位测试。在验证平台的有效性后,通过比较分析发现,不同调制方式中,低数据速率的调制具有更好的通信性能;并且体内的信道模型比穿透体的信道模型有更好的通信性能;对于体内定位,在RSS定位算法的基础上,利用调整矩阵改进最大似然算法,并应用于沿小肠传播路径中的若干点,结果有效地验证了系统的定位算法。

鄂尔多斯盆地南部建庄地区直罗组铀矿化定位研究

笔者总结建庄地区目的层直罗组构造、沉积相、氧化带及伽玛异常展布特征,建立“三过渡”铀矿定位模式,指导了建庄地区铀矿找矿工作,指出“三过渡”复合区规模是影响工业矿体连续性的主要因素,对铀矿找矿和综合研究具有很好的借鉴意义。

三峡库区典型农业小流域溶解态养分输移对“源—汇”景观格局的响应

“源—汇”景观格局反映了流域土地利用配置与空间要素分布,导控流域能源流动与水沙过程,是影响小流域养分流失的重要因素。为探明景观格局对不同降雨类型下,农业小流域溶解态养分输移的影响,以三峡库区石盘丘小流域的传统农业型集水区与农林复合型集水区为研究对象,监测不同强度侵蚀性次降雨事件中,两个集水区出口断面处径流溶解态氮、磷浓度,利用航测数据结合最小累计阻力模型识别“源-汇”景观空间格局,引用景观空间负荷对比指数(Location-Weighted Landscape Index,LWLI)进一步分析小流域溶解态养分输移对“源—汇”景观格局的响应机制。结果表明:(1)传统农业型集水区内,“源”“汇”景观面积比为1.8︰1,以“源”景观为主,景观垂直分异性明显;农林复合型集水区内“源”“汇”景观比例约1︰1,且均衡分布,但高陡坡区域占比高、平均坡度大。(2)两种类型集水区内,溶解态氮、磷流失负荷均表现为暴雨>中雨>大雨,而不同降雨事件中,传统农业型集水区养分输出负荷及其变异系数均高于农林复合型集水区,养分输移波动性强,更易受到降雨强度变化的影响。(3)农业用地在两种集水区内均是主要的养分流失来源,但受坡度限制,其他林地可能是农林复合集水区中重要的养分迁出区域;传统农业型集水区的LWLI高达0.75,表征了该集水区的高氮、磷流失风险;农林复合型集水区LWLI为0.28,养分输出量低,这是合理的景观空间格局与农林复合经营模式共同作用的结果。“源—汇”景观格局对小流域养分流失影响显著,可通过“源—汇”景观空间负荷对比指数对小流域养分流失风险进行判别,并为“源—汇”景观格局优化及小流域面源污染防控提供依据。