快速路复杂立交桥区立交桥型指路标志对行驶速度的影响

为研究城市快速路不同立交匝道类型条件下立交桥型指路标志对行驶速度的影响,以立交桥型指路标志、立交桥匝道类型作为实验控制因素设计12个实验场景,通过驾驶模拟实验获得车辆行驶状态数据;以速度、速度标准差、加速度、加速度标准差为速度类指标,结合配对T检验的方法进行影响研究.问卷统计结果显示,31名被试中47.83%认为城市快速路出口指路标志系统中"立交桥型指路标志"指路效果最佳,61.9%被试认为指路标志将影响其行驶速度,主要使其速度变慢.数据分析结果表明,受匝道线形复杂程度作用,不同类型匝道条件下,与三级预告标志组合设置时立交桥型指路标志对速度类指标的影响不同:定向匝道条件下,驾驶员速度类指标未受影响;半定向、环形匝道条件下,立交桥型指路标志作用范围内车辆行驶速度变低,立交桥型指路标志降速作用的关键影响区域集中在相应匝道出口附近.半定向、环形匝道条件下,作用范围逐段内驾驶员受立交桥型指路标志显著性影响的速度类指标、关键区域不同.同时,立交桥型指路标志、三级预告标志组合使用时,两者效用间存在一定的耦合作用,这种耦合作用在半定向、环形匝道条件下具有不一致性.     

Principles of the roof cut short-arm beam mining method (110 method) and its mining-induced stress distribution

Since the 1960 s, mining science and technology in China has experienced two technical innovations, i.e.the ‘‘Masonry Beam Theory(MBT)" and ‘‘Transfer Rock Beam Theory(TRBT)". Based on those theories, the conventional mining method(being called the 121 mining method) was established, consisting of excavating two tunnels with a pillar left for mining a working panel. However, with increasing mining depth,engineering geological disasters in the underground caverns have been frequently encountered. In addition, the use of the coal-pillar mining results in a large amount of coal resources unexploited. In order to address the problems above, the ‘‘Roof Cut Short-Arm Beam Theory(RCSBT), being called the 110 mining method)" was proposed by He Manchao in 2008. The 110 mining method features the mining of one coal seam panel, excavating necessarily only one roadway tunnel and leaving no pillars. Realization of the 110 mining method includes the following steps:(1) directional pre-splitting roof cutting,(2) supporting the roof by using high Constant Resistance Large Deformation bolt/cable(CRLD), and(3) blocking gangue by hydraulic props. This paper presents an overview of the principles, techniques and application of the 110 mining method. Special emphasis is placed on the numerical simulation of the geostress distribution found in the mining panel using the 110 method compared to that of the 121 method. In addition, the stress distribution on the ‘‘short beam" left by the roof cutting when performing the 110 method was also investigated using both numerical simulation and theoretical formulation.     

浅论中国电信市场监管政策

在对电信监管政策研究的各个领域与环节中 ,大多数研究者多从经济学的角度分析电信监管的必要性和相应的经济制衡措施 ;还有部分研究者仅局限于从感性的角度对某一种监管手段进行评论或分析。而该文即以政策科学为手段 ,从微观的、政策科学的角度对我国电信市场监管政策、电信监管政策的演变历程进行实证研究 ,运用政策科学的理论分析了现有政策在实施中所取得的成绩 ,指出了政策缺乏权威性、强有力的监控体系和不配套等存在的问题。     

Complexity analysis of blast-induced vibrations in underground mining: A case study

Blasting in geological bodies is an industrial process acting in an environment characterized by high uncertainties (natural joints, faults, voids, abrupt structural changes), which are transposed into the process parameters (e.g. energetic transfer to rock mass, hole deviations, misfires, vibrations, fly-rock, etc.). The approach to this problem searching for the “optimum” result can be ineffective. The geological environment is marked out by too many uncertainties, to have an “optimum” suitable to different applications. Researching for “Robustness” in a blast design gives rise to much more efficiency. Robustness is the capability of the system to behave constantly under varying conditions, without leading to unexpected results. Since the geology varies from site to site, setting a robust method can grant better results in varying environments, lowering the costs and increasing benefits and safety. Complexity Analysis (C.A.) is an innovative approach to systems. C.A. allows analyzing the Complexity of the Blast System and the criticality of each variable (drilling, charging and initiation parameters). The lower is the complexity, the more robust is the system, and the lower is the possibility of unexpected results. The paper presents the results obtained thanks to the C.A. approach in an underground gypsum quarry (Italy), exploited by conventional rooms and pillars method by drilling and blasting. The application of C.A. led to a reliable solution to reduce the charge per delay, hence reducing the impact of ground vibration on the surrounding structures. The analysis of the correlation degree between the variables allowed recognizing empirical laws as well.     

关于“巷道周围岩体内应力分布曲线形态和破裂带范围计算方法”的商榷

本文从实验资料和理论分析两个方面,对目前国内已出版的有关“岩体力学”和“矿山压力”论著中普遍引用的巷道周围岩体内应力分布曲线形态”进行质疑。提出了在巷道周围岩体内“两带”(弹性带和塑性带)交界处切向应力不连续(即存在一个“跳跃”)的观点。进一步指出了目前通用的“破裂带范围计算方法”缺乏理论依据。文中还对不同岩石条件下,“两带”交界处切向应力差值的大小作了初步分析。     

汉语拼音复韵母 ao、iao 与日语汉字读音的对应关系

试从汉语的韵母入手,找出汉语拼音复韵母ao、iao和日语音读的对应关系,从而提高日语学习者记忆单词的效率以及增加掌握汉字读音的准确率。本研究表明,在汉语中辅音和韵母ao组词的汉字,日语一般都将它们读成オ段长音。而在汉语中辅音和复韵母iao组词的汉字,日语吴音汉音一般都读作オ段拗长音。另外,因为辅音j、q、x不能和复韵母ao相拼读,只能和复韵母iao相拼读,一般日语吴音读做オ段拗长音,汉音读做オ段长音,个别读作入声音。     

基于Petri网的地下洞室出渣系统建模仿真

出渣是控制开挖进度的重要工序,如何配备最适宜的自卸汽车台数,使装载机的利用率最高、岔口前排队概率最小,保证出渣运输工作顺利进行,同时满足不同道路等级的行车密度要求,是出渣过程中需要考虑的问题.结合溪洛渡工程,将地下厂房洞室群多工作面、多工种交叉作业情况下的出渣问题抽象为有限源多级随机服务系统,重点介绍了应用Petri网理论建立出渣系统模拟模型和模型实现的过程,并采用三阶段法的仿真策略,对水电站地下洞室群出渣系统进行仿真研究,取得了与实际情况相近的仿真模拟成果,为机械方案的优选提供了决策支持.     

A novel virtual machine deployment algorithm with energy efficiency in cloud computing

In order to improve the energy efficiency of large-scale data centers, a virtual machine(VM) deployment algorithm called three-threshold energy saving algorithm(TESA), which is based on the linear relation between the energy consumption and(processor) resource utilization, is proposed. In TESA, according to load, hosts in data centers are divided into four classes, that is,host with light load, host with proper load, host with middle load and host with heavy load. By defining TESA, VMs on lightly loaded host or VMs on heavily loaded host are migrated to another host with proper load; VMs on properly loaded host or VMs on middling loaded host are kept constant. Then, based on the TESA, five kinds of VM selection policies(minimization of migrations policy based on TESA(MIMT), maximization of migrations policy based on TESA(MAMT), highest potential growth policy based on TESA(HPGT), lowest potential growth policy based on TESA(LPGT) and random choice policy based on TESA(RCT)) are presented, and MIMT is chosen as the representative policy through experimental comparison. Finally, five research directions are put forward on future energy management. The results of simulation indicate that, as compared with single threshold(ST) algorithm and minimization of migrations(MM) algorithm, MIMT significantly improves the energy efficiency in data centers.     

论文化产业政策的实施机制

从近几年我国文化产业政策实践看，我国文化产业政策的绩效并不理想。绩效不理想的原因是多方面的，而未能形成有效的政策实施机制是其主要原因之一。从文化产业政策实施三要素之间的关系出发，探讨了文化产业政策的实施机制，指出了我国文化产业政策在执行过程中存在的问题，提出了优化我国文化产业政策实施机制的对策。     

呼图壁低压水敏储层保护钻井液技术

枯竭气藏型地下储气库地层压力系数低,钻完井中储层保护难度大.针对呼图壁储气库水平井大压差钻完井中井筒工作液深度侵入储层造成严重储层损害的难题,通过储层岩石的矿物组分分析和膨胀性、润湿性、自吸钻井液滤液的渗透率损害率测定,分析了呼图壁储气库储层损害的主要方式,即强水敏地层的黏土水化膨胀和致密储层的液锁损害;提出了强化抑制...     

Influence of backfilling rate on the stability of the “backfilling body-immediate roof” cooperative bearing structure

To reduce the cost of backfilling coal mining and utilize the underground space of coal mines, a new backfilling mining method with low backfilling rate called constructional backfilling coal mining (CBCM) is proposed. The “backfilling body-immediate roof” cooperative bearing structure of CBCM is analyzed by establishing the model of the medium thick plate on an elastic foundation. The influence of the backfilling rate on the stability of overlying strata is analyzed by the numerical simulation experiment. The control effect of CBCM is verified by a physic similar simulation test. The economic benefit of CBCM is analyzed. The conclusions are: the deformation characteristics of the immediate roof and critical backfilling spacing in CBCM can be analyzed based on the Hu Haichang’s theory. Exerting the bearing capacity of the immediate roof is beneficial to the stability of the overlying strata. The CBCM has a good control effect on the overburden in Xinyang Mine when the backfilling rate is lower than 25%. The backfilling cost of per ton coal is 37.39 yuan/t when the backfilling rate is 13.7%, with a decrease rate of 56.63% than the full-filling. The research results can provide theoretical support for the application of CBCM in coal mining.     

Utilising the scientific method to demonstrate that slender beam/column behaviour is the dominant behavioural mechanism leading to roof/rib failure

As per most other earth science engineering problems, the underground coal geotechnical environment and the way in which roof and rib support interacts with the rock mass are complex issues. It is therefore generally recognised that without prudent simplification, the complexity of the problem will overwhelm all current geotechnical methods of modelling, not least for the reason that a rock mass can never be characterised to a level that allows a ‘‘non-simplified" analysis. The fact that numerical models, which are commonly purported to be a ‘‘simulation" tool and the so-called epitome of advanced geotechnical engineering, always need to be ‘‘calibrated" to a known reality is taken to be conclusive proof of this statement. While the problem should not be oversimplified(i.e. the dominant failure mechanisms or critical data input parameters should not be ignored), without question judicious simplification is at the heart of all engineering design, to the point that it has a well-established name –‘‘reductionism". The hypothesis addressed in this paper, is that horizontal and vertical stress-driven slender beam and column behaviour(which includes unstable Euler Buckling) are respectively the dominant(but not only) roadway roof and ribline behavioural mechanism that(if not controlled) can lead to excessive deformation,failure and eventual collapse. As a part of the Scientific Method, a hypothesis can only be tested via real-world observations, measurements and analyses in establishing it is a credible Theory. Utilising the Scientific Method, this paper demonstrates that slender beam/column behaviour is the dominant instability mechanism within a coal mine roof/rib subject to elevated horizontal/vertical stress conditions and therefore, must be representatively accounted for in any credible empirical, analytical, or numerical approach to coal mine roof/rib stability assessment and associated ground support design.     

实现AOI取像路径规划的混合遗传算法

为了提高自动光学检测过程中图像采集的效率,需要对取像的视场位置和取像的路径进行优化.现有取像方法的一个共同点就是效率偏低,鉴于此提出了基于混合遗传算法的路径规划方法,该方法可一步完成路径优化,进而提高取像的时间效率.仿真结果验证了该算法的有效性,在相同的条件下,可以减少取像时间,提高检测效率,克服了传统顺序取像方法的缺点,针对电路板进行离线路径规划,不会影响实际在线取像的时间.基于混合遗传算法的路径规划方法,有效解决了自动光学检测中路径规划关键问题,对提高工业生产效率,具有重要意义.     

城市快速路网分布式匝道协调控制

针对城市快速路网的匝道调节问题,提出了分布式匝道协调控制策略.首先采用动态图混杂自动机与元胞传输模型相结合的方法建立了快速路网的交通流模型;然后分析了系统的平衡状态集,在此基础上设计了分布式匝道协调控制,使得系统状态渐近收敛到某个平衡状态;最后对北京三环快速路网进行了仿真实验.实验结果验证了控制方案的有效性和可行性.     

液压脉冲试验台建模与仿真研究

针对液压脉冲试验台要能可靠可控地产生脉冲波形这个关键技术问题,以管道－容腔物理模型为基础,首次建立了斜坡输入模型,推导出了斜坡响应输出表达式。计算结果表明斜坡输入模型的超调量最大为63.7%。根据阶跃输入和斜坡输入模型,从理论上分析得出了在斜坡输入时间不大于系统振荡周期十分之一时,斜坡输入可以作为阶跃输入来处理。利用Matlab和液电比拟方法对阶跃模型、斜坡模型进行了数字仿真,仿真结果表明通过调整容腔体积、管道长度以及管道直径等系统参数,能产生符合标准的脉冲波形。     

Application of ventilation simulation to spontaneous combustion control in underground coal mine: A case study from Bulianta colliery

Spontaneous combustion of residual coal in longwall goaf is a long standing hazard. Airflow leakage into goaf is a major driver to the hazard and this issue deteriorates where longwalls are operating in multiple seams and shallow covers because mining-induced cracks are very likely to draw fresh airflow into goaf due to presence of pressure differential between longwall face and surface. To study the problem more critically, a ventilation simulation package ‘‘Ventsim" is used to conduct a case study from Bulianta colliery. It was found that isolating and pressurizing active longwall panel can mitigate the problem and the pressure differential can be adjusted by varying performance of auxiliary fan and resistance of ventilation regulator. A booster ventilation system can also mitigate the problem by adjusting fan duties. Ventilation simulation is a powerful tool to study spontaneous combustion control in underground coal mine.     

基于深度学习的新能源爬坡事件预测方法

随着新能源渗透率的逐渐增大,有功功率不平衡的爬坡事件时有发生,甚至造成较大负荷损失。因风电和光伏预测的精度不够,需要考虑的运行场景较多,时域仿真不能满足在线评估要求。提出一种基于深度学习的方法,综合考虑机组和联络线的调节能力,利用堆叠降噪自动编码器提取各层特征训练支持向量机。将风电、光伏和负荷预测数据及上一时刻联络线功率等相关量作为输入,是否发生爬坡事件为输出,通过支持向量机快速预测是否发生爬坡事件。实际电网的仿真结果表明,本研究方法快速准确,能够对爬坡事件进行有效辨识。     

基于深度学习的新能源爬坡事件预测方法

随着新能源渗透率的逐渐增大,有功功率不平衡的爬坡事件时有发生,甚至造成较大负荷损失。因风电和光伏预测的精度不够,需要考虑的运行场景较多,时域仿真不能满足在线评估要求。提出一种基于深度学习的方法,综合考虑机组和联络线的调节能力,利用堆叠降噪自动编码器提取各层特征训练支持向量机。将风电、光伏和负荷预测数据及上一时刻联络线功率等相关量作为输入,是否发生爬坡事件为输出,通过支持向量机快速预测是否发生爬坡事件。实际电网的仿真结果表明,本研究方法快速准确,能够对爬坡事件进行有效辨识。     

新媒体时代的舆论规律及危机应对

随着社会结构变迁、利益格局重构、思想观念变革,民众利益诉求也呈现出了多元化、多层级、多途径的趋势。互联网的异军突起,更为公众参与公共事务讨论和自身利益诉求表达,搭建了一个足以颠覆任何传统新闻传播介质和规律的快捷的革命性的平台。以网络为代表的“第四媒体”、“第五媒体”、“自媒体”的迅猛崛起,注定了新信息传播矩阵和舆论格局已经构建成型。面对新形势、新任务、新要求,我们必须以长远的眼光、理性的思维和科学的态度,审视、关注和充分利用互联网新技术、新手段,积极构建和优化网络媒体生态,良性协调“主流舆论场”与“民间舆论场”关系,最大限度增加两大舆论场“公约数”,用网络的手段提高执政水平。     

“金课”背景下有机化学虚拟仿真实验的设计与实践

在全国高校打造五大“金课”的大背景,虚拟仿真实验教学项目建设已逐渐成为高校人才培养、学科建设的必要组成部分。有机化学虚拟仿真实验是有机化学实验教学的重要手段,可以实现真实实验难以进行的实验题目,是有机化学实验的良好补充。分析了有机化学虚拟仿真实验和有机化学真实实验的优缺点,并按照“金课”标准,探讨了如何设计有机化学虚拟仿真实验。