VAE乳胶粉掺量对苯丙乳液水泥基路面填缝料拉伸性能的影响

采用控制变量法研究了VAE可再分散乳胶粉掺量对聚合物水泥填缝料(Polymer-Modified Cement Based Composed Joint Sealant,PCJS)拉伸性能的影响规律。将苯丙乳液水泥基路面填缝料中的部分填料替换为VAE乳胶粉制成新型的PCJS,测量了不同VAE乳胶粉掺量下PCJS的拉伸强度、拉伸断裂伸长率、拉伸峰值应变、拉伸模量,观察记录了拉伸破坏形态,分析了温差对PCJS早期拉伸强度性能的影响,研究了苯丙乳液(SAE)和VAE乳胶粉对PCJS的复合改性作用。试验结果表明:30℃温差处理对PCJS早期拉伸强度发展无显著影响。且在28d标准条件下养护完成后,随着VAE乳胶粉掺量增加,PCJS拉伸强度和拉伸模量显著上升,拉伸破坏形态由"内聚破坏"向"粘结破坏"转变,拉伸断裂伸长率和拉伸峰值应变随乳胶粉掺量增加呈先上升后下降趋势,当乳胶粉掺量为2%~3%时,PCJS拉伸变形性能最佳。     

Preparation and characterization of aligned carbon nanotubes coated with titania nanoparticles

Titania (TiO2) is an environmental-friendly photo- catalyst material with high stability and efficiency, so its preparation methods received extensive atten- tion[1―4], and the products were advanced from dis- persed nano-powder and fastness nano-film[5,…     

共形平坦黎曼流形中具有平行第二基本形式的子流形

设Ｍ＾ｎ＋ｐ是ｎ＋ｐ维共形平坦黎曼流形，本文对具有平行第二基本形式的子流形作了讨论，将我们现有结论推广到了更一般的情形。     

铝交联膨润土催化性能的研究

经不同时间沉降而得的精制原料土制备交联膨润土,发现用沉降30分钟而得的精制原料土制备的交联膨润土催化活性较好.测定了不同焙烧温度和焙烧时间对交联臌润土裂化活性的影响,用XRD分析了不同焙烧温度、OH/Al(摩尔比)比值对d(001)峰的影响.用IR,D1A,BET手段表征了交联膨润土的物化特性。实验结果表明用山西浑源膨润土制备的交联膨润土是一种良好的催化裂化催化剂材料。     

一种面向基因与疾病关系的文本挖掘方法

结合模式匹配、生物医学本体及共现技术,设计了一种自动抽取基因与疾病、基因与基因之间关系的文本挖掘方法,并开发了一个可以处理海量文本数据的系统.该系统可抽取与疾病相关的基因实体,挖掘基因与疾病、基因与基因之间的关系,衡量基因与疾病实体的相关性,并为分析基因与疾病、基因与基因之间的关系提供了网络可视化工具.实验结果表明,系统在测试数据集上抽取基因与疾病之间的关系可获得83.0%的综合测评率,抽取基因与基因之间的关系可获得78.5%的综合测评率.该系统已成功应用于乳腺癌及相关基因的研究.     

南宁市突发性污染事故隐患调查

为摸清南宁市污染事故隐患情况,于1998年4月至7月调查南宁市各主要工矿企业、油库、仓库等单位的周围环境状况、生产工艺流程、有毒、有害、易燃、易爆品的种类、数量分布以及防患措施.对调查结果进行统计分析,认为南宁市目前的各种突发性污染事故隐患较多,防范重点在于易燃品、农药、化工原料及化学品、腐蚀品和剧毒品等几类物质.防范工作的方向应定在各种工厂企业,有关的公司以及各种加油站,在防范区域上应以江南区及兴宁区为主.     

具有自学习功能的电力负荷模糊推理预测

考虑到电力负荷预测问题中存在的不确定性,采用模糊推理预测方法进行负荷预测的研究。该方法利用电力最高负荷和国内生产总值的历史数据建立模糊推理规则,从而进一步建立最高负荷跟国内生产总值之间的模糊蕴涵关系,通过模糊推理得到了负荷预测结果。为了使模型能够象专家一样不断地总结新的经验并调整原有的经验,模型克服了其它模型中知识的凝固性,具有自学习功能。利用某些区的实际数据进行分析计算,得到了满足的结果。     

Robust H∞ guaranteed cost satisfactory fault-tolerant control for discrete-time systems with quadratic D stabilizability

The problem of robust H∞ guaranteed cost satisfactory fault-tolerant control with quadratic D stabilizability against actuator failures is investigated for a class of discrete-time systems with value-bounded uncertainties existing in both the state and control input matrices. Based on a more practical and general model of actuator continuous gain failures, taking the transient property, robust behaviour on H∞ performance and quadratic cost performance requirements into consideration, sufficient conditions for the existence of satisfactory fault-tolerant controller are given and the effective design steps with constraints of multiple performance indices are provided. Meanwhile, the consistency of the regional pole index, H∞ norm-bound constraint and cost performance indices is set up for fault-tolerant control. A simulation example shows the effectiveness of the proposed method.     

Visualization of the complex structure and stress field inside rock by means of 3D printing technology

Accurate characterization and visualization of the complex inner structure and stress distribution of rocks are of vital significance to solve a variety of underground engineering problems. In this paper, we incorporate several advanced technologies, such as CT scan, three-dimensional（3D） reconstruction, and 3D printing, to produce a physical model representing the natural coal rock that inherently contains complex fractures or joints. We employ 3D frozen stress and photoelastic technologies to characterize and visualize the stress distribution within the fractured rock under uniaxial compression. The 3D printed model presents the fracture structures identical to those of the natural prototype. The mechanical properties of the printed model,including uniaxial compression strength, elastic modulus,and Poisson’s ratio, are testified to be similar to those of the prototype coal rock. The frozen stress and photoelastic tests show that the location of stress concentration and the stress gradient around the discontinuous fractures are in good agreement with the numerical predictions of the real coalsample. The proposed method appears to be capable of visually quantifying the influences of discontinuous,irregular fractures on the strength, deformation, and stress concentration of coal rock. The method of incorporating3 D printing and frozen stress technologies shows a promising way to quantify and visualize the complex fracture structures and their influences on 3D stress distribution of underground rocks, which can also be used to verify numerical simulations.     

平面有界三次系统有限奇点分布举例

通过构造有界的平面三次系统,证实了（1）其有限奇点的5－4（5个奇点指标为＋1,另4个奇点指标为－1）,3－2,2－1,＋1四种分布均可实现;（2）仅有一个指标为＋1的有限奇点的有界三次系统至少有11种类型;（3）赤道附近轨线拓扑结构相同的有界三次系统它们有限奇点的分布可以有不同类型。