谢林模型的统计物理学

社会性隔离是人类社会作为复杂系统涌现的典型现象之一.托马斯·谢林（Thomas C.Schelling,1921—2016）在1971年提出了解释种族隔离现象的著名模型——谢林模型.半个多世纪以来,谢林模型吸引了相当数量的研究,由此产生了许多重要结论 .本文旨在对谢林模型的统计物理以及晚近的进展做一概要介绍,以阐明统计物理和社会动力学之间的深层关系.     

沥青混合料级配离析的无损检测技术

沥青混合料的级配离析是影响路面使用寿命的关键因素之一。本文分别采用无核密度仪和激光纹理仪检测评价沥青混合料的内部离析和表面离析。研究表明,无损检测技术可以快速检测获取大量的试验数据,然后运用概率统计的方法进行处理,能够比较科学的评价沥青路面的施工离析程度。     

杂交早稻米质性状遗传的初步研究

测定武昌夏季和广西秋季栽培的杂交早稻新组成威伐242F1、F2，汕优242F、F2，威20B，珍汕97B和湖大242的糙米率、精率、米粒长、米粒宽、粒形（长／宽）、垩白等级和碱消值。分析以上性状的F2变异，估算垩白等级和碱消值的广义遗传力分别为52．26％和80．40％。同时研究了异地不同季别栽培条件对米质性状的影响。     

微量元素锡、砷在U_(74)重轨钢中的晶界偏聚

用Auger谱仪和X射线面扫描探测了U_(74)重轨钢在加热到1200℃奥氏体化以后再以不同冷速进行冷却的条件下微量元素Sn,As的偏聚情况。实验结果表明:在缓慢冷却的条件下,U_(74)轨钢中会发生Sn,As的晶界偏聚。600℃长时间等温可加剧钢中As元素的偏聚,但不加剧Sn的偏聚。     

索塔锚固区钢纤维混凝土的工艺试验

首先通过室内试验优选出索塔锚固区纤维混凝土配合比,然后在现场泵送浇注2.44 m×1.22 m×1.22 m长方体试验块和3.4 m×1.0 m×2.3 m剪力钉试验块,最后浇注节段足尺模型.采用合理的振捣工艺,避免振捣过程中砂浆上浮和纤维外漏,从而试验块未出现开裂,外观质量良好.对优选的钢纤维混凝土进行了120 m和216 m泵送试验,系统泵压都在20 MPa左右;停机0.5h后泵压约为22 MPa,并且混凝土土出机坍落度大、和易性良好.通过泵送阻力计算,预测优选的钢纤维混凝土能达到306 m的泵送高度.     

Non-equilibrium segregation of boron on grain boundary in Fe-30%Ni alloy

The moving boundary non-equilibrium segregation during recrystallization and the influence of pre-deformation in Fe-30%Ni Alloy at1000℃ was investigated by the PTA (particle tracking autoradiography) technique, optical and electron microscopy. The results indicated that intensity of boron segregation on moving boundary after different deformation is concerned with the pre-deformation degree and the movingspeed of the boundary. The TEM (transmission electron microscopy) result showed that the dislocation density nearby the moving boundary increase obviously. The phenomena are discussed by the widening grain boundary mechanism.     

用数字图像技术评价沥青路面的表面离析

为寻找适宜的路面施工工程质量控制方法,基于数字图像技术,开发了一套判别和评价沥青路面表面离析的方法．该方法包括：离析的判别、路面非离析的定义和路面离析程度的评价．平行试验结果表明,该方法可以满足路面工程质量评价的精度要求,同时具有成本低、易操作等优点,对提高沥青路面施工质量、延长使用寿命有帮助．     

Cr/Mn偏析对高碳轴承钢珠光体–马氏体带状组织的影响分析

The effect of Cr/Mn segregation on the abnormal banded structure of high carbon bearing steel was studied by reheating and hot rolling. With the use of an optical microscope, scanning electron microscope, transmission electron microscope, and electron probe microanalyzer, the segregation characteristics of alloying elements in cast billet and their relationship with hot-rolled plate banded structure were revealed. The formation causes of an abnormal banded structure and the elimination methods were analyzed. Results indicate the serious positive segregation of C, Cr, and Mn alloy elements in the billet. Even distribution of Cr/Mn elements could not be achieved after 10 h of heat preservation at 1200°C, and the spacing of the element aggregation area increased, but the segregation index of alloy elements decreased. Obvious alloying element segregation characteristics are present in the banded structure of the hot-rolled plate. This distinct white band is composed of martensitic phases. The formation of this abnormal pearlite–martensite banded structure is due to the interaction between the undercooled austenite transformation behavior of hot-rolled metal and the segregation of its alloying elements. Under the air cooling after rolling, controlling the segregation index of alloy elements can reduce or eliminate the abnormal banded structure.     

硅片氧化过程及其对硅中杂质分布影响的分析

利用带活动边界的“D＇Alembert变分法”分析了硅片的氧化过程及此过程所引起的硅中杂质的再分布.氧化过程的理论分析结果及对两种常见的杂质初始分布的计算结果均与实验相符.