采场直接顶的结构力学特性及其刚度

分析了采场四边形体直接顶的结构力学特性，给出了直接顶刚度的计算方法．按刚度把直接顶分为似刚性、似零刚度和中间型刚度三类，给出了确定不同直接顶刚度类型的方法，分析了不同直接顶刚度条件下的支架工作阻力和顶板下沉量的关系．     

浅谈即时通讯软件的开发技术

分析了即时通讯软件的运行模式，协议选择及开发技术，提出了开发过程中的有关处理方法。     

Dynamic buckling mechanism of pillar rockbursts induced by stress waves

Rockbursts are sudden and violent rock failures that can lead to huge production and equipment losses,injury or death of mining workers.Buckling has been regarded as one of the key mechanisms of rockbursts,which are often induced by dynamic loads from mining excavations,such as drilling and blasting in underground mining.The paper attempts to investigate the dynamic buckling mechanism of pillar rockbursts in underground mining,by considering rockbursts as a dynamic stability problem of underground rock structures.The results include:(1) A new explanation of the "sudden and violent" phenomenon of rockbursts,characterized by exponential growth of the amplitudes of transverse displacement responses,even in the presence of rock damping;(2) Identification of the critical role in inducing rockbursts of dynamic loads that bear frequencies approximately double the natural pillar frequency;(3) The greater influence on rockburst occurrence of the amplitude of dynamic component relative to the static component of loads;and(4) Quantification of the relative effects of stress waveform of dynamic loads on pillar rockbursts,which are in decreasing order if other parameters remain constant:rectangular,sinusoidal,and exponential waveforms.Application examples are provided and limitations of the approach are discussed.This research is motivated by the on-going and ubiquitous occurrence of rockbursts in underground excavations all around the world.In contrast to conventional methods that use rock specimens or rock materials to study rockbursts,this investigation emphasizes the structural effects on rockbursts,which has potential applications in hard rock mining engineering.     

油水井套管的腐蚀及防护理论、实验与应用--油水井套管电化学保护测试方法

通过对比各种电化学保护测试法 ,介绍了接触测试法在对套管保护电位测量中的应用 .由于参比电极与套管间的距离缩短 ,使参比电极处于被测套管的被测点处 ,证明该法能够反映套管的被保护情况 ,但测试费用较高 ,一般仅在条件允许或具有实验价值的测量时采用 .而地表保护电位测试法、瞬间断电法、E -lgI测试法等建议在常规测试中应用 .     

Parallel Indexing: Infrastructure and Space

As governments around the world open the public coffers in an attempt to pull their economies back from collapse, Holger Kehne and Jeff Turko describe how they have extended the work of the Architectural Association Diploma Unit 12 to incorporate the pertinent subject of infrastructure and architecture, employing ‘indexical systems’. Copyright © 2009 John Wiley & Sons, Ltd.     

食用芒果过敏的研究进展

芒果是我国亚热带地区重要经济作物,含有多种功能性成分,然而大部分人群在接触或食用芒果后会出现不同程度的过敏临床反应。本文简单介绍食用芒果导致的过敏反应,包括接触性皮炎、口腔过敏症状、交叉过敏等,并详细阐述了芒果导致过敏现象的两种途径,以及不同过敏原物质、反应类型和发病人体的免疫途径。根据过敏原Allergome数据库(http://www.allergome.org/)分析得到芒果中所含有的9种主要的过敏原,并对其中2种过敏原蛋白,即抑制蛋白和几丁质酶进行了结构域的分析。通过对芒果过敏交叉反应的介绍,得到不同物种中的过敏蛋白氨基酸序列具有高度同源性,而这些同源性序列决定与免疫球蛋白E具有相同作用的表位。本文以期从分子水平上提供芒果低过敏品种培育的新途径和过敏防治的新思路。     

薄直接顶大采高综采工作面切顶留巷合理参数研究

针对薄直接顶大采高工作面顶板垮落后不能及时充满采空区,造成上覆厚硬顶板在工作面侧向形成悬臂梁结构,进而向留巷侧传递覆岩压力导致留巷围岩破坏失稳的现象,以某矿12408工作面薄直接顶、厚硬基本顶条件为工程背景,采用理论分析、数值模拟和现场监测相结合的研究方法,研究了薄直接顶大采高综采工作面切顶留巷合理参数。建立了留巷顶板的力学模型,量化了未贯穿面的拉应力与切顶高度和切顶角度的关系,确定了未贯穿面拉应力随切顶高度和切顶角度的变化规律,得出了切顶角度一定时,未贯穿面处的拉应力与切顶高度近似指数函数规律分布,拉应力随切顶高度的增大而增大,且增长速率逐渐加快;切顶高度一定时,未贯穿面处的拉应力随切顶角度的变化曲线呈抛物线形,随着切顶高度增大,未贯穿面处的拉应力超过极限所需的切顶角度的范围也增大。数值模拟方法分析了留巷中锚索轴力变化系数的变化规律、区段煤柱和相邻巷道竖直方向应力的分布特征,确定了11 m的切顶高度和大于0°的切顶角度即可切断顶板间的应力传递。现场考虑到实际岩层赋存条件的复杂多变、爆破后切缝面的不平整性和贯通程度的差异性以及保证厚硬顶板在矿山压力作用下顺利垮落,采用13.6 m的切顶高度和10°的切顶角度,结合顶板垮落后的碎涨系数,理论验证了顶板垮落后的高度大于工作面实际高度,即垮落顶板能够及早支撑上覆岩层,减轻覆岩运动对留巷和煤柱稳定性的影响。现场监测到巷道顶底板及两帮变形量较小,围岩较稳定,验证了数值模拟结果的可靠性以及切顶卸压技术的可行性,可为类似条件的切顶留巷提供借鉴和参考。     

基于即时行为检测的P2P文件共享系统信任模型研究

针对P2P文件共享系统中只根据历史行为计算信任度和服务节点的选择不合理的问题,提出了基于即时行为检测机制IBD的P2P文件共享系统信任模型,该模型在信任度计算和选择服务节点时采用了即时行为检测方法,提高了信任度计算的准确性和选择服务节点的合理性。仿真结果表明了该模型的优越性。     

Age dissociates recency and lag recency effects in free recall.

The temporal relations among word-list items exert a powerful influence on episodic memory retrieval. Two experiments were conducted with younger and older adults in which the age-related recall deficit was examined by using a decomposition method to the serial position curve, partitioning performance into (a) the probability of first recall, illustrating the recency effect, and (b) the conditional response probability, illustrating the lag recency effect (M. W. Howard & M. J. Kahana, 1999). Although the older adults initiated recall in the same manner in both immediate and delayed free recall, temporal proximity of study items (contiguity) exerted a much weaker influence on recall transitions in older adults. This finding suggests that an associative deficit may be an important contributor to older adults' well-known impairment in free recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于支付平台系统的多种收费方式

介绍了交换机计费系统通过支付平台系统实现多种收费 ,收费方式包括实时托收、预存托收、代收通、一触即发 .实时托收是当用户产生一定费用时立即从银行托收 ,预存托收是预存用户入网时托收预存款 ,代收通是用户去银行缴费 ,银行代收现金 ,一触即发是用户通过企业的客户服务系统的语音提示将他产生的费用从个人帐户存入企业帐户