多媒体技术在小学数学教学中的作用

科学技术的日新月异发展,推动了素质教育的进程,多媒体技术已经走进了课堂,本文阐述了小学数学教学应用多媒体技术,激发了学生浓厚的学习兴趣,化解了教学重点难点,营造了良好的氛围,优化了课堂教学,提高了课堂教学效率。     

易在河南

伏羲,中华民族人文始祖,是我国古籍中记载的最早的王,所处时代约为新石器时代早期,他根据天地万物的变化,发明创造了八卦,成了中国古文字的发端,也结束了“结绳纪事”的历史。他又结绳为网,用来捕鸟打猎,并教会了人们渔猎的方法,发明了瑟,创作了《驾辨》曲子。他的活动,标志着中华文明的起始,也留下了大量神话传说。     

多媒体-小学数学教学的得力助手

多媒体技术的发展使小学数学教学模式发生了根本性变化。课堂体现了学生的主体性原则,多媒体的应用丰富了教学内容,灵活了教学方式,点燃了学生思维的火花,提高了学生听课效率,有效解决了数学教学中的重难点,多媒体是小学数学教学的得力助手。     

70 m以上空心高墩施工的温度应力应变控制

介绍了关家沟特大桥工程概况,分析了桥墩轴线的放样施工,提出了施工中消除温度影响的控制技术,并进行了理论计算,对该技术的现场应用情况进行了探讨,得出了该方法正确的结论,为同类工程积累了经验.     

柴油发电机励磁绕组的改进

本文介绍了柴油发电机组励磁系统出现的故障及原因,设计了新的励磁装置,并制定了使用控制措施,通过实践检验,排除了类似故障,从而保证了工程施工的安全、质量、进度和效益,取得了较好的经济效益。     

盘点城市

近些年,河南城乡建设取得长足进步,给我们留下太多的惊喜和惊奇。花园多了,建筑高了,广场大了,道路宽了,河道治理了,污水少了,绿化率提高了……     

2012年中国建材素质拓展掠影

这是一次心的历练,一段生命的体验,一堂寓意深远的课程,更是值得永远铭记和感恩的回忆。两天的拓展训练里,我们洒下了汗水,收获了成功;留下了眼泪,带走了感动;战胜了恐惧,建立了信心;突破了极限,坚实了凝聚力。探索与思考,祝福与欢笑,分歧与统一,遗憾与启迪,在我们的合力协作中愈显珍贵。两天的拓展训练完满结束,这是每一个人的胜利,更是集体的胜     

翻转课堂在初中英语高效课堂构建中的作用

随着信息技术与英语教学的深度整合,翻转课堂教学这一新的教学模式进入了英语教学,有效解决了如何创设英语语境的问题,为学生提供了丰富的个性化英语学习语境,使不同层次的学生都得到了发展与提高。由于教师将学习的权利交给了学生,学生成为了学习的主体,构建了有效教学评价机制,实现了多元化、全方位的英语教学评价。     

小型热回收装置的可行性研究

通过回收排气中的余热对引入空调系统的新风进行预热或者预冷,可以减少空调系统的能耗。分析了不同装置的原理和性能特点以及适用性特征,初步探讨了热回收设备配置的合理性并举例说明了其节能效果,从而论证了应用的技术可行性。提出了一种简易的经济分析计算方法,评价了经济效果,论证了经济可行性。得出了小型热回收装置用于暖通空调系统可行的结论,并展望了乐观的应用前景。     

简论多媒体技术在小学语文教学中的应用

科学技术的日新月异发展,多媒体技术已经进入了课堂,优化了课堂教学,提高了教学效率,突出了学生主体地位,激发了学生学习欲望,调动了学生学习的积极性、主动性、创造性,扩大了知识容量,促进了学生想象思维的发展,实现了课堂教学过程的最优化。本文试就多媒体技术在小学语文教学中的应用进行了探讨。     

单管塔的计算方法及优化设计

目前,单管塔的设计计算方法常用的有两种,本文提出了两种新的计算方法,通过理论分析和实例计算,对这四种方法进行了具体的比较,得出一些结论,并对各种方法作出评论。还提出了一种单管塔最优化设计的方法,依据大量算例,得出了单管塔的各参数随塔高、风压的变化规律。     

A comparison of shear stress estimation methods for a single geobag on a rough bed

There are several methods for estimating bed shear stress in the literature, but comprehensive comparisons among them are limited and under specific conditions. This study compared these methods first on a bare smooth bed, and then for a single geobag on a rough bed in the interest of determining the stability of geobags used in riverbank protection structures. The geobag was filled with cement or sand and tested under different open channel flow conditions. The turbulent kinetic energy method appeared to best represent the local bed shear stress on the geobag when using the newly calibrated proportionality constants. The Reynolds stress method via extrapolation was relatively unaffected by changes to the geobags shape and measurement locations, suggesting this method inadequately represents the local bed shear stress. The Patel method and the universal law of the wall method failed to represent local bed shear stress in the rough bed cases due to instrument limitations and the breakdown of the law of the wall. This study highlights the impact of different methods on the bed shear stress estimation.     

软黏土中某内支撑式深基坑稳定性安全系数分析

软黏土中深基坑稳定性安全系数是基坑设计的重要指标,目前基坑稳定性安全系数评估方法主要有传统经验公式法和有限元强度折减法。针对深厚软黏土中某倒塌内支撑式深基坑,采用传统经验公式法和有限元强度折减法对该基坑稳定性安全系数FS进行了计算分析,比较了不同土体强度指标计算结果的差异,结合其它学者的研究,对各计算方法及其所采用土体强度指标的合理性进行了评价。研究结果表明:无论是应用经验公式法还是有限元强度折减法,采用不排水抗剪强度指标su计算得到的基坑FS均比较接近1.0,而采用土体c,?强度指标得到基坑FS均远大于1.0。应用有限元强度折减法时,数值计算不收敛准则相对交点法得到基坑FS偏大。采用交点法与Terzaghi法得到基坑FS最接近1.0,与基坑处于极限平衡状态事实相符。     

Estimation of phosphorus flux in a regulated channel

During a nutrient loading study in the Okanagan River Basin, British Columbia, the regression relationship between phosphorus concentration and the Okanagan River discharge was shown to be not statistically significant. Phosphorus flux could, therefore, not be determined by conventional methods which rely on the concentration-discharge relationship. The reason for failure of conventional methods is the regulated nature of the Okanagan River flow. Two sampling strategies for chemical analysis of water samples were applied: (a) simultaneous, based on manual collection of sample replicates; and (b) sequential, using an automatic device to obtain a series of point concentration measurements. These sampling strategies provided a basis for nutrient flux estimation by the following methods: (a) partial load method, resulting from simultaneous sampling; and (b) flow interval method, based on sequential sampling. Load estimates and their confidence limits derived from the partial load method were compared with loads obtained by the flow interval method. There was a high level of correlation between the load estimates. Annual trends are more appropriately investigated by the flow interval method, cross-sectional load variability and confidence limits should be assessed by the partial load method.     

Using a genetic algorithm to develop a pile design method

A genetic algorithm (GA) was used in this study to develop a standard penetration test (SPT)-based design method for the axial capacity of driven piles. A total of 72 pile load tests was collected from literature and divided into two groups based on their measurements. The first group had the load-transfer distribution measurements for extracting both the unit side and tip resistances. These unit resistances were correlated by the GA with soil measurements and pile properties to develop the design method. The second group, where only the total capacity measurements were available, were used to validate the new design method and compare its performance with three existing SPT-based design methods. The new GA-derived design method considers nonlinear relationships with the effective stress and pile length and provides an unbiased prediction with a low coefficient of variation (COV) of 40.0 %, while the three existing methods overestimate the capacity by a factor of 1.62 to 1.65 with a high COV of 40.3 % to 52.8 %, which could result in an under design of pile foundations. This study shows that the GA was able to obtain complex relationships with great accuracy and the new design method can be applied to new cases reasonably well.     

某地铁隧道工后沉降稳定性判断研究

地铁隧道建设规模不断扩大,工程建设期间经常需要判定工后沉降是否稳定,其关系到后期设备安装等工期计划。工程实践中常采用理论公式法、经验推算预测法及数值分析等方法。根据某地铁明挖隧道实例,采用上述三种方法判断研究工后沉降稳定问题,为合理安排工程筹划提供参考。     

Comparison of the simplified methods of the ISO 13790 standard and detailed modelling programs in a regulatory context

The CEN standards that support the European Energy Performance of Buildings Directive requirement for calculation of the energy consumption of buildings allow various methods to be used for the same calculation. The impact of using the different methods within the updated ISO 13790 standard for space heating and cooling energy calculations was examined with a parametric analysis of a common building specification. The impact was assessed by considering the energy band, which would be assigned for the building based on the calculation results. The standard describes three different methods that can be used for the calculations: a monthly quasi-steady state method, a simplified hourly method and detailed simulation. For most cases studied, differences in the building rating given by the various methods were a maximum of one band. More significant differences were noticed in some cases. Parameter values in the monthly method were determined, which would lead to improved matching.     

层状岩体坝基抗滑稳定分析中的几个问题

展状岩体坝基抗滑稳定分析是坝工建设中重要问题之一。但是分析方法还不完善,目前正进行多方探索,其中用极限平衡理论进行分析比较普遍,近年来有限单元法也在逐步开展,有的工程还补充进行脆性材料模型试验。本文以某工程为例,介绍了上述方法的应用,并对稳定分析中的一些问题提出初步看法.     

Air tightness measurement with transient methods using sudden expansion from a compressed chamber

Air tightness in an escape route of a building is important in preventing a fatal disaster by smoke spreading during a fire. To measure air tightness, transient methods using sudden air expansion from a small compressed air chamber into a room are proposed. Pressure variations in the chamber and the room are measured, and effective leakage areas are evaluated using differential and integral transient methods. The results of the two transient methods are compared with results from a typical steady method using an external blower fan. As a result, it was confirmed that all three experimental methods show good linearity between the imposed open hole area and the estimated effective leakage area. Therefore, the effective leakage area estimated using the transient methods could be converted to the equivalent leakage area of the steady method. The transient methods proposed in this study are expected to be more conveniently adopted for measuring air tightness if a suitable conversion factor is preliminarily evaluated.     

Three methods for verifying and validating the simulation of a construction operation

A simulation model must be verified to confirm that it describes correctly its intended real world process under study; moreover, the simulation results obtained must be a valid representation of the process. This study presents three activity-based white-box methods for assisting a user in verifying and validating construction simulations. The first method reports a simulation by listing all activities in the chronological order of their executions, so that a user can contrast the simulated progress against the actual progress in the real world. The second method summarizes the operating counts and mean durations of all activities over the simulated time period, to enable a user to evaluate whether all activities have been executed correctly during simulation. The third method generates an activity cycle report for any selected resource entity, so that a user can examine whether the entity is moving in the correct logical and chronological order during simulation. The three methods can be used jointly to debug a simulation model, so as to confirm that the simulation is correctly conducted and the obtained results are valid. The three methods are implemented in a simulation system in the form of corresponding reports. A concreting process is employed to illustrate these methods.