Effects of thermal-oxidative aging on rheological properties of montmorillonite modified bitumen

Organic montmorillonite(OMMT) modified bitumen nanocomposites was prepared by melt blending.The effects of thin-film oven test(TFOT) and pressure ageing vessel(PAV) on rheological properties of pristine bitumen and OMMT modified bitumen were investigated by dynamic shear rheometer(DSR).The results show that complex modulus(G*) increases,phase angle(δ) decreases and rutting factor(G*/sin δ) is enhanced for the pristine bitumen after TFOT,whereas G*,δ and G*/sin δ of OMMT modified bitumen have a little change before and after TFOT.Besides,the pristine bitumen exhibits a large increase of G* and a great decrease of δ after PAV aging.However,the changes in G* and δ of OMMT modified bitumen are small before and after PAV.Compared with the pristine bitumen,OMMT modified bitumen presents a lower fatigue factor(G*sin δ) after PAV.As a consequence,resistance to thermal-oxidative aging of bitumen is remarkably improved due to the introduction of OMMT.     

Effect of organophilic montmorillonite on thermal-oxidative aging behavior of SBS modified bitumen crack filling material

Styrene-butadiene-styrene (SBS) modified bitumen crack filling material with organophilic montmorillonite (OCFM) was prepared by melt blending. X-ray diffraction analysis shows that the interlayer spacing of organophilic montmorillonite (OMMT) in OCFM is widened and an exfoliated structure may be formed. Thermal-oxidative aging behavior of OCFM and SBS modified bitumen crack filling material (SCFM) was investigated. The experimental results indicate that the rate of thermal-oxidative aging of OCFM is much slower than that of SCFM, which can be attributed to barrier of exfoliated structure of OCFM to oxygen. Funded by the National Natural Science Foundation of China (50773061)     

紫铜表面Fe-Al共渗层的耐磨性实验研究

为了提高紫铜表面耐磨性,对其进行Fe-Al共渗处理,并对共渗层的耐磨性和组织结构进行分析。结果表明,共渗层的显微硬度可达386HV,耐磨性比紫铜提高了105%~116%,比渗铝层提高了26%~33%。这种变化主要是因为铁元素能阻滞β→α+γ2共析转变,细化晶粒,改善渗层的脆性,共渗后紫铜表面得到α+(α+γ2)亚共析体,其中α+γ2相为类似珠光体的片状结构,硬度较高,而α相较软,相当于软基体上分布有硬质点,起到减磨的作用。     

拟线性退化抛物型方程的柯西问题及其解传播速度的有限性

本文研究拟线性退化抛物型方程柯西问题广义解的存在唯一性,并在一定条件下证明了解的传播速度为有限。     

一种新的仿真系统评估模式

仿真程序和仿真引擎之间的交互作用以及它们的动态行为通过传统仿真系统的V&V技术无法评估,为此规则常常会用于仿真系统的V&V技术,但引入规则后仍存在规则修改和管理困难的缺陷,针对此问题,提出了一个基于动态规则执行技术的仿真系统校核与验证模式.该模式中包含6类建模元素,约束被形式化描述为规则,通过规则引擎的执行检测在仿真执行期是否产生规则违反来判断仿真系统是否存在问题,从而实现对仿真系统的动态V&V.为仿真系统的评估提供了新思路,同时由于规则与系统的分离性也便于仿真系统的修正与完善.     

一种新的入侵检测方法

随着Internet网络的快速普及,针对计算机及网络基础设施的攻击已经成为了一个越来越严重的问题.针对入侵检测技术提出了一种基于敏感时间滑窗的检测算法STSW,扩展了数据挖掘在入侵检测中的应用.以KDD CUP99作为实验数据研究了参数的选取对检测效果的影响,将该算法的执行效率与基于SPADE挖掘序列模式的入侵检测算法进行了对比.结果表明:入侵检测算法可以取得比较满意的检测效果,并且执行效率要优于基于SPADE的入侵检测算法.     

A new model for evaluating the electrical conductivity of nonferrous slag

Electrical conductivity of molten slag is an important physicochemical property for designing the refining process in electric smelting furnaces.Though conductivities of many slag systems have been measured,the quantitative relationships of conductivity with slag composition and temperature are still very limited.In this article,the Arrhenius law was used to describe the experimental data of conductivities for CaO-MgO-Al2O3-SiO2,CaO-Al2O3-SiO2,CaO-MnO-Al2O3-SiO2,as well as CaO-MgO-MnO-Al2O3-SiO2 systems,and...     

泡沫沥青混合料冷再生技术

根据国内外最新研究成果,介绍了沥青发泡原理及特性并对其影响因素分别从宏观和微观角度进行了分析,探讨了泡沫沥青混合料的设计方法,最佳拌和用水量试验,养生条件对泡沫沥青混合料的影响,实验室检测方法,力学特性的研究及其影响因素.文中列举了沥青发泡技术在一些温拌沥青混合料中的应用,提出并分析了泡沫沥青今后发展的几个重要问题,包括泡沫沥青混合料设计与评价方法,发泡剂的研制与选择,泡沫沥青改性及其工艺改进方法.     

综合电压传递矩阵的一种新方法

本文将二阶有源RC网络作为基本单元,利用级联及反馈技术,提出了一些新的综合电压传递矩阵的方法和电路,其特点是不需要积分器及多绕组变压器,包含较少的有源元件;同时本文也讨论了利用反相运放作为级联的线路,分析了它们的优点。     

一种新的尺度不变特征提取方法

为解决传统尺度不变特征点提取算子计算复杂度高、抗噪能力不强以及特征点位置发生漂移等问题,提出一种基于尺度空间因果关系的尺度不变特征提取方法.首先原图像与高斯函数进行卷积获得高斯平滑图像;然后在原图与高斯图像中分别提取Harris角点作为候选特征点;最后以高斯图像上的候选特征点为中心向原图上投影寻找对应的特征点作为最终的尺度不变特征点.实验结果表明,该算法容易实现、计算效率高、抗噪能力强.该算法能为后续视觉处理提供稳定抗噪的尺度不变特征点.     

A new measure for evaluating spatially related properties of traffic information credibility

With the wide applications of sensor network technology in traffic information acquisition systems, a new measure will be quite necessary to evaluate spatially related properties of traffic information credibility. The heterogeneity of spatial distribution of information credibility from sensor networks is analyzed and a new measure, information credibility function （ICF）, is proposed to describe this heterogeneity. Three possible functional forms of sensor ICF and their corresponding expressions are presented. Then, two feasible operations of spatial superposition of sensor ICFs are discussed. Finally, a numerical example is introduced to show the calibration method of sensor ICF and obtain the spatially related properties of expressway in Beijing. The results show that the sensor ICF of expressway in Beijing possesses a negative exponent property. The traffic information is more abundant at or near the locations of sensor, while with the distance away from the sensor increasing, the traffic information credibility will be declined by an exponential trend. The new measure provides theoretical bases for the optimal locations of traffic sensor networks and the mechanism research of spatial distribution of traffic information credibility.     

A new hybrid decision support tool for evaluating the sustainability of mining projects

The integration of sustainable development challenges and opportunities into the decision making process during the design and/or implementation of multi-disciplinary mining projects is generally not supported by decision support systems(DSS). A new hybrid decision support tool, which features an integrated assessment of sustainable development issues as they apply to mining projects, is hereby proposed. The proposed DSS framework, named ‘‘Acropolis DSS", can be used to assist involved stakeholders in critical decisions, especially when addressing issues such as stakeholder participation, transparency,and trade-offs. The proposed DSS is based on a multi-criteria decision analysis combined with the multi-attribute utility theory.     

试析养老服务创业团队的培养

我国已步入老龄化社会,推动养老事业由＂生存型＂向＂文化型＂转变,建设培养合格的养老服务创业团队十分重要.结合齐齐哈尔工程学院家政教学中心创业团队建设,对养老服务创业团队的培养内容和培养方法进行了分析探讨.     

一种新的软硬件协同综合及其处理器分配方法

在实际应用中,软硬件协同设计过程包含了软硬件结构的确定,这一确定过程具体包括了处理器件的选择、任务到元件的映射和任务时间调度的安排。现存有很多基于协同设计的启发式算法,但其中的大部分只能应用于简单的结构和非流水化的应用。提出了一种能够应用于软硬件协同设计的处理器分配和流水化处理的新方法。这种方法能够根据元器件对系统性能的提高程度反复选择器件,据此分配任务、创建流水平台,并且能够消除冗余平台。     

A new approach to test generation for combinational circuits

Aimed at the generation of high-quality test set in the shortest possible time, the test generation for combinational circuits (CC) based on the chaotic particle swarm optimization (CPSO) algorithm is presented according to the analysis of existent problems of CC test generation, and an appropriate CPSO algorithm model has been constructed. With the help of fault simulator, the test set of ISCAS’85 benchmark CC is generated using the CPSO, and some techniques are introduced such as half-random generation, and simulation of undetected faults with original test vector and inverse test vector. Experimental results show that this algorithm can generate the same fault coverage and small-size test set in short time compared with other known similar methods, which proves that the proposed method is applicable and effective.     

一种新的模糊神经元网络建模方法

基于零阶Ｔ－Ｓ模糊模型,本文指出了一种实用的输入输出的数据进行复杂系统的模糊神经元网络建模的方法,该方法的主要目的是解决模糊神经元网络中结构辨识的困难。 种所谡语言模型被用来寻找系统输入变量的最佳组合。     

一种新的引出熵函数的绝热法

本文提出了一种新的绝热法，和一般绝热法所不同的是，该方法不仅环境角度出发，故不需要选择被考察体系的独立变量，也不需要引入关于体系性质的各种不一定具有普遍意义的假定或猜测，体系的任意性由此可得到保证。为了使环境的任意性也能得到保证，本文对环境热源的性质了不作任何限制，本文还从逻辑学的角度对热力学的一些结论作了考察，指出某些条件的非必要性，并给出了熵增原理等一些重要结论的充分必要条件，本文还通过对可设计假定的分析，指出了公理化热力学应有的特点。     

一种新的间断型备件需求预测方法

针对间断型需求因需求发生随机、需求量值波动大而导致预测困难这一问题,提出一种新的备件需求预测方法.该方法能分别预测需求发生时间和非零需求发生时的需求量值.对于0-1需求发生时间序列,采用调制方法对其进行平滑处理,运用神经网络对调制后的0-1时间序列进行预测,获得需求发生时间的预测值.采用时间聚合方法对实际备件需求时间序列进行预测,将滚动预测应用到解聚合过程中,得到备件的需求量预测值.使用三一重工砼活塞和核电设备的备件需求数据对方法进行验证,结果表明,该方法的预测精度要优于Croston方法、指数平滑法以及BP神经网络,证明了所提方法的有效性和准确性.     

价值工程新探

商品是个利益综合体，经营中必须顾及各方的利益。长期以来，VE学科缺乏对生产厂商和公众利益的研究。因此，在功能领域中没有列入交换功能和社会公益功能，在生命周期费用中也没有计算市场交易费用，这是不全面的。在全面推行VE中，应该加以拓展。近期推广价值链(VC)、供应链(SC)、企业资源计划(ERP)等都是应用了VE原理。本对上述问题作了些新的探索。     

教学质量评价模型

介绍模糊数学中综合评判的数学模型,应用此模型评价教师授课质量．通过对学生问卷调查,得到学生对教师的教学评判矩阵,请专家给出权重分配,从而得到对教师的综合评价．