共查询到18条相似文献，搜索用时 484 毫秒
1.
在露天开采过程中遇到断层时,由于煤层突然错位,造成剥采比剧变,工程接续困难。因此,过断层期间剥采比合理控制和矿山工程平稳过渡接续是露天开采的技术难题之一。笔者通过建立剥采比与断层落差、产状及煤层厚度数学模型,研究不同煤柱留设宽度对边坡稳定的影响;分析了矿山工程发展速度与同时采煤台阶数的关系,计算确定了过断层期间确保矿山工程平稳过渡接续的动态降深速度和生产能力接续方式。结合胜利东二号露天矿过F61断层进行实例研究。结果表明：过断层开采方式和生产能力接续方法可有效均衡生产剥采比,保证产量稳定,提高矿山经济效益。 相似文献
2.
3.
4.
苏南太湖地区水稻氮肥施用与环境可持续发展 总被引：9，自引：0，他引：9
研究了苏南水稻不同施氮量与产量、养分吸收量,养分利用率之间的关系。在此基础上,探讨了水稻的经济合理施氮量。试验结果表明,水稻产量、养分吸收量、养分利用率随着氮肥用量的增加而增加,但增量越来越小,如果充分考虑到生态效益和经济效益,则水稻适宜施氮量应为２２５ｋｇ／ｈｍ＾２,相应产量为７５３３ｋｇ／ｈｍ＾２。 相似文献
5.
为了揭示不同工程复垦措施下采煤沉陷区土壤质量的演变特征,基于10年的长期定位试验,研究了晋东南采煤沉陷区在表土剥离和混推复垦两种工程复垦方式下,10年间土壤的理化性质、微生物群落结构及土地生产力的变化特征。结果表明：复垦初期,表土剥离处理的复垦土壤理化性质、土地产出能力均显著高于混推复垦。复垦7年时,土壤的物理性质、微生物群落结构组成与多样性和土地产出能力基本一致,差异不显著。复垦10年间,0~20 cm土层土壤养分含量始终表现为表土剥离>混推复垦;10年间表土剥离较混推复垦收益累计增加6609元/hm2,因此,表土剥离复垦方式在保持耕层土壤肥力及综合收益上要优于混推复垦。但复垦10年后,2种复垦方式土地生产力和肥力水平均很低,说明复垦方式只是矿区复垦过程的一个前置环节,矿区土壤的生态恢复是必须要结合施肥措施进行。 相似文献
6.
采用土壤养分状况系统研究法（ASI）,又称土壤养分状况综合评价法,研究河西灌区施钾对啤酒大麦产量、品质的影响,并确定甘肃河西灌区合理经济的施钾量。结果表明固定N、P及微量元素等养分后,与不施钾比较。施钾的啤酒大麦的产量增加279～1325kg／hm^2,增幅5．9％～27．9％,千粒重提高0．1～2．8g;钾水平在0～150kg／hm^2范围内,随着施钾量的增加,产量、经济效益、千粒重也随之增加,籽粒粗蛋白含量降低。说明施钾提高了啤酒大麦的产量与经济效益,改善并保证了啤酒大麦的品质,合理经济的钾用量为150kg／hm^2. 相似文献
7.
棉田多种群优势天敌捕食棉铃虫动态研究 总被引：4，自引：0，他引：4
本文采用二次通用旋转组合设计方法，研究了草间小黑蛛、小花蝽、龟纹瓢虫３种天敌与棉铃虫共存系统的动态捕食量数学模型，对捕食量模型分析可以了解棉铃虫种群密度与天敌复合种群密度之间的关系及对捕食量的影响、各类天敌种群间的交互作用。同时还建立了各类天敌数量增长的子模型。为棉田棉铃虫防治策略提供理论依据。 相似文献
8.
施氮对春玉米产量和经济效益的影响 总被引：1，自引：0，他引：1
采用随机区组设计试验,研究施氮对春玉米产量和经济效益的影响。结果表明,不同施氮量对春玉米经济性状、产量和经济效益的影响不同,各处理间产量差异极显著,以施氮量150kg/hm2的处理表现最佳;玉米产量和经济效益随施氮量的增加呈现先增加后降低的趋势;氮肥的农学效率随施氮量增加而降低。单位面积玉米产量和施氮量具有显著的回归关系,最高产量施氮量是:N161.9kg/hm2,最高产量为8351.9kg/hm2;最佳产量施氮量为:N144.7kg/hm2,最佳产量8324.1kg/hm2。 相似文献
9.
甘蔗不同熟期品种合理搭配与提高蔗糖分关系的研究 总被引：3，自引：0，他引：3
根据甘蔗不同熟期品种蔗糖分积累变化和高糖期出现迟早早存在差异的特点,应用其积累动态模拟模型,探讨不同品种搭配形式与提高蔗糖分的关系,从理论上阐明早,中,迟熟品种合理搭地延长高糖期和提高蔗糖分的作用,并给出品种搭配求算原则和方法,为糖厂确定不同期品种的种植比例,提高经济效率提供指导依据。 相似文献
10.
为获得烤烟优质高产栽培的合理株型，以‘中川208’品种为试验材料，开展不同施氮量与种植密度组合大田试验，研究烤烟株型性状与烟叶产质量的关系，进行烤烟株型性状与烟叶产值、烟叶化学成分可用性指数(Chemical Components Usability Index, CCUI)的回归关系分析，提出烤烟合理株型特征。结果表明，施氮量与种植密度对烟草株型性状、干物质积累量、烟叶经济性状、化学成分产生显著影响，适当增加施氮量，可以促进烟株主茎、叶片生长、干物质积累，增加烟叶产量、产值，提升化学成分协调性；增加密度使烤烟单株主茎变高变细，叶片变小，干物质积累减少，但群体烟叶产量、产值增加，化学成分协调性先升高后降低。中部叶是影响烟叶产值、质量的关键因素。构建烟草株型性状与烟叶产值、CCUI的回归方程，获得‘中川208’平顶期合理株型性状范围：株高124.77～128.70 cm，茎围9.61～9.84 cm，节距6.20～6.35 cm，下部叶长56.06～58.05 cm、叶宽28.15～30.57 cm，中部叶长63.74～69.05 cm、叶宽29.93～30.36 cm，上部叶长48.4... 相似文献
11.
The measurement of in-site crustal stresses are carried out in Yan Shi Tai coal mine.The outburst-proneness of 6# coal seam are studied with five indexes. Based on the strength testing of coal,the strength criterion is set up. The energy criterion is put forward in the light of engineering practice.According to the "three criteria" mechanical model,the prediction of danger zone of coal burst of 6# coal seam in this mine is carried out. 相似文献
12.
High pressure pulsed water jet (HPWJ) is a new technology of effectively improving coal seam permeability. However, the mechanism of increased permeability is not yet clear, which restricts the application of HPWJ in different coal seams. From the perspective of improving permeability by coal matrix shrinkage, the impelled dynamic equations is established based on analysis of coal dynamic effects by water jet. According to theoretical analysis of the stress state of coal matrix, it is concluded that HPWJ can promote coal matrix shrinkage, and the relationship equation between jet impact-coal matrix is derived. Besides, the gas seepage function in the coal slotted by the HPWJ is gained by using PM model, which provides theoretical support for generalizing the technology in the coal mine. 相似文献
13.
Based on the coal seam of Zhao zhuang coal mine and Si he coal mine belong to Jin cheng anthracite Mining Group in Shanxi province, by using the self developed three axial servo controlled seepage equipment for hot fluid solid coupling of coal containing methane, parallel experiments for permeability of helium and methane under different gas pressures are carried out to quantitatively study the influence of Klinkenberg effects on the permeability of coal. Meanwhile, the problem of permeability decreasing caused by fluid pressure decreasing and gas desorption is eliminated by controlling the effective stress. The results show thatthe Klinkenberg effect is obvious under low gas pressure. With the increase of gas pressure, the permeability of coal decreases at first and then increases. The inflection points of gas pressure for Klinkenberg effect are about 0.9 MPa both for coal samples in Zhao zhuang coal mine and Si he coal mine. When the effective stress is constant, with the increase of gas pressure, the permeability increment caused by Klinkenberg effect decreases, while permeability increment caused by coal matrix shrinkage increases. Coal matrix shrinkage has a close relationship with the mechanical properties of coal rock mass. For the coal sample with a poor mechanical property, coal matrix shrinkage is more obvious. 相似文献
14.
The experimental study of physic and mechanic properties of coal seam in a coal mine is presented, and the relation between coal-gas outburst and the strength, the elastic modulus, as well as the deformation property of coal seam is analysed on the basis of the experimental results. 相似文献
15.
ECMB, which is developed by Amoco company in USA, has very prospective. On the basis of the study on adsorption characteristics of mixture gas in coal, the principle of ECMB has been explored. The order of adsorption capacities of coal for several gases is: CO 2>CH 4>N 2>H 2 when coal adsorbs gas. In 2 member mixture gases, adsorption capacities of coal for mixed gases, methane and carbon dioxide tally with Langmuir equation, but not does for nitrogen and hydrogen. The substance of the increasing drawing ratio of coal seam gas by using ECBM is decreasing adsorption amount of methane in coal by emptying the other gas or gases into coal seam. N 2 is better gas than CO 2 in the process of using ECMB. 相似文献
16.
《Journal of Landscape Research》2017,(6)
To obtain the deep displacement of the coal seam in the working face,multi-point displacements were installed in the coal seam, but the installation of multi-point displacement is differen tunder different geological conditions. This paper is based on the splitting and merging of 7_1 coal and 7_2 coal in Huaibei Mining(Group) Co., Ltd., and analyzes properties of the roof andcoal in the 7_2 coal of the lower coal seam of bifurcation area, and calculates the damage depth of the floor in the process of 7_1 coal mining. The multi-point displacement meter installation is often challenged by hole collapse, stuck pole and broken installation rod in 7_2 coal of the soft coal seam of bifurcation area, as a result, the base points can't be installed in the specified location. In view of this, this paper adopts a new anchor cable mounting rod which can install the whole base points to the specified location without stuck pole or broken mounting stem. All the basic displacement data can be obtained, and the law of mine pressure appearance in stope and tunnel can be accurately controlled, which can be used to maintain the stability of roadway and the safety of stope. 相似文献
17.
为降低乳制品运输成本,合理安排运输,提高乳制品运输企业的经济效益,通过对河北省某运输公司乳制品车辆的运输成本、车型及效益分析研究,确定了2006～2008年变动成本路桥费、加油费2项占总成本的比例分别为62.89%、64.01%、54.74%,并确定了主要运输成本所占比例及其从高到低的次序;对不同年度、不同月份、不同车型车辆的运输收入、成本、利润及其变化进行了分析;12.5米、230马力的新型箱式半挂车为乳品运输的最佳运输车辆;2006年半挂车1、5、8月份运输纯利润最高,10月份次之,2、12月纯利润最少;年运输总收入11、5、8月运输总收入最高,6、1、2月运输总收入最少;2006年半挂车年收益率为10.18%,乳品运输车辆是一种高风险、中收益的投资方式。 相似文献
18.
为了在最大程度上解决城市土地资源配置与经济建设要求相匹配的问题，实现城市土地利用综合效益最大化目标，以呼和浩特市市区为例，结合2001—2016年研究区城市土地利用结构和布局变化特征，围绕经济-社会效益目标分别运用目标规划法和层次分析法对2030年用地需求方案进行模拟预测和择优，并通过CLUE-S模型对上述2种目标的优化方案进行空间模拟和最佳用地方案决策。结果表明：（1）2001—2016年研究区城市建设用地总面积增率达到94.104%，其中增幅较大的2类用地为交通运输用地和住宅用地。（2）与现状城市用地结构变化趋势不同，基于经济效益、社会效益目标的优化方案中，增幅最大的城市建设用地类分别为商服用地和工矿仓储用地，且2种方案的城市建设用地结构均衡度比2016年现状值分别高出0.259、0.462，各类城市建设用地的面积构成趋于动态平衡的态势。（3）2种不同效益目标优化方案的城市建设用地预测总面积有所不同，经济效益方案比社会效益方案高出30.828 km2。社会效益优化方案在城市用地结构及布局的动态平衡度上优于经济效益方案，设定其为最佳城市用地优化方案。 相似文献