Early Hydration and Setting Process of Fly Ash-blended Cement Paste under Different Curing Temperatures

A specially developed ultrasonic measurement apparatus (UMA) was used to in situ monitor the setting process of fly ash blended cement paste. Combined with the results of Vicat Needle tests, isothermal calorimetric measurement, XRD analysis, SEM morphology and compressive test, the influence of curing temperature (20, 40, 60, and 90 ℃) and fly ash content (0,10%, 20% and 30%) on the setting and hydration process of fly ash blended cement paste was analyzed. The results show that setting and hardening process of fly ash blended cement paste at elevated temperature can be clearly identified into three stages including dormant stage, acceleration stage and deceleration stage. The increasing of curing temperature greatly accelerates the setting and hardening process. However, the content of fly ash does not have significant effect on the setting in condition of 90 ℃. Besides, the initial and final setting time of cement paste is correspondent with the time of duration of dormant stage and the time of UPV value is 1500 m/s (T1500), respectively. Thus, the UMA can be used to determine the initial and final setting time of cementitious material under different curing temperatures. The compressive test results indicate that the paste with 20% fly ash presents higher compressive strength than the plain paste at curing temperatures of 90 ℃. Therefore, appropriate amount of fly ash is beneficial for concrete in the high temperature curing conditions.

FRACTAL PROPERTIES OF POLAR SETS OF RANDOM STRING PROCESSES

This paper studies fractal properties of polar sets for random string processes. We give upper and lower bounds of the hitting probabilities on compact sets and prove some sufficient conditions and necessary conditions for compact sets to be polar for the random string process. Moreover, we also determine the smallest Hausdorff dimensions of non-polar sets by constructing a Cantor-type set to connect its Hausdorff dimension and capacity.

Detrital Mode and Geochemistry of the Shurijeh Formation (Late Jurassic-Early Cretaceous) in the Central and Western Parts of the Intracontinental Kopet-Dagh Basin, NE Iran: Implications for Provenance, Tectonic Setting and Weathering Processes

Petrographical and geochemical methods were combined to investigate the provenance, geodynamic and weathering history of the Shurijeh sandstones, Kopet-Dagh Basin. The point-counting method and XRF technique are used for modal and geochemical analyses. Based on petrographical examinations, it seems that the Shurijeh sandstones are mainly deposited in the craton interior and recycled orogen belts. In addition to petrographical investigation, geochemical analyses （major oxides and trace elements） of Late Jurassic-Early Cretaceous rocks reveal that the sedimentation processes are performed in a passive continental margin. Such interpretation is supported with geodynamic and paleogeographical studies of the Kopeh-Dagh basin during this time. The geochemical investigations suggested that the composition of probable source rocks mostly was acidic-intermediate with minor mafic igneous rocks. Based on the above, Paleo-Tethys remnants and their collision-related granitoids, in the south and west of Mashhad, may have been the source area for these rocks. CIA values, which range from 63.8 to 94.9 in samples, are suggesting a moderate to relatively high degree of alteration （weathering） in the source area. Therefore, petrographical and paleogeographical studies of siliciclastic rocks can be used for the provenance, tectonic setting and paleoweathering studies in the source area.

Quantitative Prediction of Reduction in Large Pipe Setting Round Process

The control manner during the process to ensure the quality of pipe products mainly relies on the operator’s experience, so it is very necessary to study the setting round process and obtain its spring-back law. The setting round process is shaping an oval section pipe into circular section, so it is difficult to provide a quantificational analysis for its spring-back process because of the curvature inequality of pipe section neutral layer. However, the spring-back law of the circle-oval process can be easily predicted. The experimental method is firstly used to establish the equivalent effect between the setting round process and the circle-oval process. The setting round process can be converted into the circle-oval process. There are two difficulties in the theoretical analysis for the circle-oval process: elastic-plastic bending problem of curved beam; statically indeterminate problem. A quantitative analytic method for the circle-oval process is presented on the basis of combination of the spring-back law of plane curved beam with the element dividing idea in finite element method. The ovality after unloading versus the relative reduction is plotted with analytical and experimental results respectively, which shows a fair agreement. Finally, the method of quantitative prediction of reduction for large pipe setting round is given based on the equivalent effect and the analytical results. Five pipes, which are needed to be set round, are used to carry out experiment so as to verify this method. The results of verification experiment indicates that, in the experimental range, the residual ovality are all under 0.35% after the once only setting round with the theoretical prediction reductions. It is much less than the 1% requirement of pipe standard. Applying the established theoretical analysis is able to correct the pipe ovality with sufficient accuracy, which provides theoretical direction to plant use.

Representation Theorems for Fuzzy Random Sets and Fuzzy Stochastic Processes

The fuzzy static and dynamic random phenomena in an abstract separable Banach space is discussed in this paper. The representation theorems for fuzzy set valued random sets, fuzzy random elements and fuzzy set valued stochastic processes are obtained.

Set-Valued Stochastic Integrals with Respect to Finite Variation Processes

In a Euclidean space Rd, the Lebesgue-Stieltjes integral of set-valued stochastic processes with respect to real valued finite variation process is defined directly by employing all integrably bounded selections instead of taking the decomposable closure appearing in some existed references. We shall show that this kind of integral is measurable, continuous in t under the Hausdorff metric and L2-bounded.

Process Auxiliary Decision-making Based on Rough Sets and Regulation Distance Computing

Computer aided process planning（CAPP） is an important content of computer integrated manufacturing, and intelligentizing is the orientation of development of CAPP. Process planning has characters of empirical and time-consuming to finalize, and the same technical aim always can be achieved by different process schemes, so intelligentizing of process decision making always be a difficult point of CAPP and computer integrated manufacturing （CIM）. For the purpose of intelligent aided process decision making and reuse of process resource, this paper proposed a decision making method based on rough sets（RS） and regular distance computing. The main contents and methods of process planning decision making are analyzed under agile response manufacturing environment, the concept of process knowledge granule is represented, and the methods of process knowledge granule partitioning and granularity analysis are put forward. Based on the theory of RS and combined the method of process attributes importance identification, the paper brought forward a computing model for process scheme regulation distance under the same attribute conditions, and conflict resolution strategy was introduced to acquire process scheme fit for actual situation of enterprise＇s manufacturing resources, so as to realize process resources＇ conflict resolution and quick excavate and reuse of enterprises＇ existing process knowledge, to advance measures of process decision making and improve the rationality and capability of agile response of process planning.

改进水平集协同FLICM的汽车零部件表面缺陷识别

针对汽车机械零部件中检测效率低、误检率高等瓶颈问题,提出了一种结合图像处理技术的方法。基于汽车副车架表面结构复杂以及缺陷异形等特征,首先通过小波邻域收缩去噪和多尺度增强算法对零件图像进行预处理,再通过水平集函数初步定位缺陷区域,最后结合空间模糊聚类进一步精确定位缺陷区域,达到对零件表面缺陷识别的目的。对工件表面划伤、压痕、气孔三种缺陷进行检测。实验结果表明:该算法相对于其它两种算法的检测率分别93.3%、86%和90%,具有较高的检测成功率。为后续缺陷零部件分类奠定良好的基础且可以满足工业检测要求。

基于AHP-模糊评价分析法的社区老年人售药机设计研究

为了提升社区生活环境中老年人用户售药机的使用体验,以及解决老年人在自主购药中的问题,在注重城市社区生活环境背景的同时,更加科学合理地对售药机设计方案进行创新。聚焦传统售药机的使用需求和使用习惯,以及现有老年人售药机存在的问题,运用AHP层次分析法将相对应的设计因素进行归纳总结,从操作、造型、人机和老年人需求4个方面构建社区老年人售药机的多层级分析模型,并归纳计算影响因素评价指标的权重;最后通过模糊综合评价分析法对设计方案进行评价,以判断设计方案是否具有可行性。将AHP与模糊评价分析法结合,使主观的设计需求转为客观准确的分析,并且通过模糊评价分析法验证结果的合理性,为老年人售药机提供有效客观的设计方法。通过对社区老年人售药机的分析和设计,提出了AHP-模糊评价分析法的集成模型应用于老年人售药机设计的可行性。

基于集对分析理论和数字化平台的山岭隧道塌方风险评价

为更准确、更科学地完成山岭隧道塌方风险评价,提出一种基于层次分析法(AHP)-熵值法(Entropy)集对分析理论的山岭隧道塌方风险评价方法。首先,选取地质因素、设计因素、施工因素、管理因素4项因素作为塌方风险评价指标体系的准则层,选取12项因素作为指标层,运用层次分析法和熵值法分别计算2级指标权重;然后,引入集对分析理论确定指标联系度,并结合置信度准则对塌方风险的等级进行判定;接着,利用Grasshopper以及Python软件,对集对分析理论进行可视化程序开发,并将其与隧道-地质BIM交互模型进行耦合,建立基于AHP-Entropy集对分析模型的隧道塌方风险数字化分析平台;最后,结合重庆某隧道实际工程,验证隧道塌方风险评价的高效化、可视化效果。研究表明:基于集对分析理论的山岭隧道塌方风险评价数字化分析平台运行时间约为2 s,与传统的隧道塌方风险评价方法相比可以大大提高风险评价效率,同时利用AHP-Entropy法确定评价指标权重,提高了评价结果的可靠性。

下级法院报请提级管辖机制之司法现状审视及完善路径——以“动态管辖调整”与“法定管辖例外”为理论基点

下级法院报请是当前提级管辖案件的主要来源。探讨下级法院报请提级管辖机制,其表层意义在于阐释“动态管辖调整”与“法定管辖例外”的发生机理,即为何需要在法定管辖及静态管辖之外,设置“动态”及“弹性”等更具灵活性的规则;其深层意义在于通过我国审级架构中“平行式柱型结构”向“金字塔体系布局”调整的路径,让各级法院深入理解裁判文书所具有的规则意义、政策效应及利益衡量价值。但实践中,受认知受限、规定抽象原则、配套机制阙如三方面因素制约,下级法院报请提级管辖面临适用标准宽严无序、裁判文书格式不统一等问题,严重影响提级管辖机制适用性、有效性。对此,为充分发挥提级管辖机制效能,首先,要结合案件要素对提级管辖案件适用标准予以明确;其次,从关键环节入手,细化提级管辖运行流程;最后,以考核激励机制为导向,充分发挥提级管辖案件的示范价值。

湿基α-半水石膏制备高强石膏制品研究

为实现湿基α-半水石膏制备高强石膏制品,研究了湿基α-半水石膏陈化时间、粉磨时间、浇筑料浆温度及缓凝剂掺量等工艺参数对高强石膏凝结时间和强度的影响,并确定最佳制备工艺。此外,采用X射线衍射、扫描电子显微镜等微观测试手段,揭示了各因素对强度的影响机理。结果表明:陈化时间越长,石膏凝结时间越短,制品强度越低;随着粉磨时间延长,石膏凝结时间显著缩短,制品强度先升高后降低;料浆温度越高,石膏凝结时间越长,制品强度越低。最佳制备工艺:陈化时间5 min、粉磨时间20 s、料浆温度20℃。在此基础上加入0.08%(质量分数)缓凝剂能够有效地延长石膏凝结时间并提高硬化强度,制备的石膏制品性能优异,绝干抗折强度为14.1 MPa,绝干抗压强度为58.3 MPa。微观测试结果表明,各工艺参数会通过改变石膏标稠用水量和水化进程来影响石膏内部结构的密实程度和二水石膏晶体的生长发育,最终影响制品硬化强度。

基于关键轮廓点的汉字矢量化及字库生成研究

古迹文字字符数字化保护过程中一直存在无规范流程、准确率低、耗时耗力等问题。针对这种情况,提出古迹文字矢量化流程,其中包括多阶段图像处理与矢量化文字提取两个关键技术。多阶段图像处理技术采用非局部均值去噪算法去除电子噪声和光照不均引入的噪声,运用直方图均衡化技术增强图像对比度,采用基于偏微分方程的Inpainting技术实现区域修复,完成受损字符图像修复。矢量化文字提取技术基于汉字笔画的特性提取更多类型的关键轮廓点,去除了冗余的轮廓点和噪声轮廓点。实验表明,本文提出的矢量化文字提取技术相较于现有方法,内存减少8.0419%,与原图相比误差小于0.15,最终提取到的字符存储到了Unicode字库中,可在文本编辑器中使用。

基于SET-AHP-FBS的液压式压合机设计

为解决现有液压式压力机产品设计开发流程过程繁琐,且创新性不足的问题,文章构建了基于SET-AHP-FBS的设计策略。通过SET分析法找到产品创新设计的必要性及设计缺口,利用AHP分析用户需求权重,基于FBS进行“需求—行为—结构”的映射,将用户需求转化为结构设计参数,得到液压式压合机的系统方案设计。借助李克特量表对设计方案进行有效性验证。研究表明,基于SET-AHP-FBS的设计策略可以有效地减少设计过程中主观因素的影响,提升产品的创新性。

基于YOLO-OpenMax的水声通信信号开集识别方法

水声通信信号调制方式随着技术进步从典型的传统调制方式发展为水声通信机厂商私有开发的新型调制方式,这使得现有的水声通信信号闭集调制识别技术实用性受到制约,但现阶段鲜有研究基于深度学习的水声通信信号调制方式的开集识别方法。针对此现状,提出一种基于YOLO图像检测识别网络和OpenMax模型的开集识别方法。利用YOLOv5网络的输出特点,将传统OpenMax模型的处理方法进行改进,提出一种两步测试方法,实现了在多径信道下的水声通信信号的开集识别。仿真实验表明:在归一化系数为0.5,信噪比等于10 dB条件下的归一化开集识别准确率达到90%以上,实测数据同样验证了本文方法的有效性。

基于AHP与Rough Set的农业节水技术综合评价

由于不同区域自然条件的差异,农业节水技术自身特点及对应用环境条件的要求,导致不同农业节水技术的应用效果存在很大差异,有较大的不确定性,因此,如何筛选合理的评价指标,构建科学、全面的农业节水技术综合评价方法具有十分重要的意义。根据对农业节水技术应用效果的实地调研,应用Delphi法从调查获得的20项评价指标中筛选出了9项农业节水技术综合评价指标。其中节水率、积温和土壤肥力属于生态因子,产投比、劳动力投入和经济投入属于经济因子,可靠性、推广程度和农民认可度为社会因子。基于以上9项指标,构建了农业节水技术综合评价指标体系.综合评价方法(ARM)通过引入经验因子α对应用层次分析法(AHP)和粗糙集(Rough Set)所获得指标权重进行修订,使指标权重更加合理化。同时,分别应用AHP、Rough Set和ARM对甘肃省武威市的地膜覆盖、秸秆覆盖和常规畦田灌溉在大田中的应用效果进行了综合评价。评价结果显示,在对地膜覆盖技术评价中,AHP法过分强调了经济效益的作用(0.44),Rough Set法则强调的是生态效益(0.33)和社会效益(0.32),弱化了经济效益(0.05),ARM修正了以上2种方法的评价结果,获得地膜覆盖的经济效益、生态效益和社会效益,分别为0.36、0.20和0.13。在对秸秆覆盖评价中,与其它两种方法相比,Rough Set法的评价结果存在显著性差异,ARM修正获得的经济效益、生态效益和社会效益,分别为0.09、0.18和0.06。在对常规畦田灌溉评价中,Rough Set法强调了生态效益(0.28),经过修正获得的经济效益、生态效益和社会效益,分别为0.24、0.01和0.13。ARM的评价结果表明,采用地膜覆盖的经济效益最佳;同常规畦田灌溉相比较,地膜覆盖、秸秆覆盖的生态性指数分别比之高0.19和0.17,主要是由于秸秆覆盖具有保墒、增加土壤有机质以及在作物生长后期调节地温的作用,地膜覆盖具有节水、提高苗期土壤温度和促进提前出苗的作用;同秸秆覆盖相比,地膜覆盖和常规畦田灌溉的社会性指数分别高112.12%、18.18%,说明这两种技术在河西半干旱地区具有良好的社会基础。可见,在西北半干旱地区地膜覆盖用于种植玉米的效果最佳,而秸秆覆盖尽管其生态效益较高,但经济效益较低,推广应用存在一定的难度。

一种基于FCM和LevelSet的MRI医学图像分割方法

对基于区域的几何活动轮廓模型中的区域项进行了改进.改进后的算法不仅解决了原算法存在的稳定性问题,同时也有效地提高了分割速度.算法还被成功地扩展到能够分割多种脑组织,且分割质量显著提高.多种子初始化方式的采用,进一步降低了算法对初始条件的敏感性,同时也减少了人工干预.对模拟和真实脑MRI图像的分割实验证明了改进的可行性和有效性,噪声条件下分割的比较分析也表明改进后的算法具有良好的韧性.

基于变分Level Set方法的图像分割

文章主要利用levelset函数隐式地追踪图像的边界来实现图像分割。在该文中首先给出了一个变分问题以及相应的Euler-Lagrange方程,并且提出了一种求解该方程的数值算法,使得计算速度有了很大的提高。数值算例表明,该水平集算法具有数值稳定性,不会出现振荡现象,可以很好地处理拓扑结构的变化。

农田水利节水灌溉发展现状及优化措施

节水灌溉是农业生产向理性化、科学化发展的新灌溉模式,是农业可持续发展和水资源合理利用的必然要求。随着农业生产的转型升级和灌溉机械设备的功能优化与产品迭代,农田水利建设中的节水灌溉技术应用成为农业生产的重要工作。近年来,在国家政策支持下,我国节水灌溉工作得到长足发展但仍面临较大挑战,探索适合我国国情的农业节水灌溉新途径与新思路,有利于促进节水灌溉技术的科学落地,真正帮助农业向资源节约型和环境友好型转变。

基于Level Set法铸造充型过程气-液两相流数值模拟

针对目前铸造充型流动模拟最为常见VOF方法的不足,建立了基于Level Set方法的气-液两相流数学模型及求解方法。应用所建立的模型,模拟了气泡的运动过程,并通过水模拟试验进行了验证,模拟结果表明,Level Set方法可以有效地模拟铸造充型过程中的气-液两相流动,是铸造模拟技术发展的新方向。