掺加石灰石煅烧煤矸石及其在水泥水化过程中的作用机理

以江苏宜兴煤矸石为主要研究对象,对其基本物性进行分析可知,其成分以SiO2、Al2O3为主,CaO含量较低;矿物组成以高岭石和石英为主,属于低钙粘土类物质。在复合矿化剂作用下于1000～1100℃高温煅烧制成活化煤矸石样,分析各活化样的结构特征,并在检验其胶凝性能的基础上,运用化学结合水量、Ca(OH)2量测定等方法对活化煤矸石水泥的水化过程进行追踪测定。研究结果表明,各活化煤矸石的胶凝性能不同,其中以1050℃保温0.5h煅烧而成的活化样对水泥强度的影响最大,将其以30%掺量替代水泥后,体系28d净浆强度达到70.16MPa。水化过程的分析结果与宏观力学强度结果基本吻合。     

铝矾土尾矿的热活化效果

铝矾土尾矿的热活化效果直接影响其在水泥混凝土中的利用率,而活化效果与铝矾土尾矿的组成、结构变化和它对水泥水化性能的影响有关.本研究将铝矾土尾矿于600～800℃煅烧2 h后,实验观察和分析了铝矾土尾矿煅烧前后组成的变化,并研究了尾矿掺量在10％～30％时水泥胶砂强度活性指数和硬化浆体的水化.研究结果显示在该温度段内温度变化对铝矾土尾矿活性影响较小,即铝矾土尾矿有较宽的热活化温度范围;当掺入30％活化铝矾土尾矿后,仅略微降低了水泥胶砂强度,而这些效果与煅烧尾矿中偏高岭石形成以及硬化浆体致密性提高有关.总体而言,经合理热活化的铝矾土尾矿具有和粉煤灰相似的作用.     

微波辐照活化煤矸石-硅酸盐水泥体系试验研究

通过宏观试验和扫描电镜(SEM)微观测试分析技术研究了微波辐照活化煤矸石及掺量对硅酸盐水泥体系的细度、凝结时间、体积安定性、火山灰活性和强度等性能的影响,结果表明,大掺量微波辐照活化煤矸石对硅酸盐水泥体系各项技术性能无不良影响;微波辐照活化煤矸石硅酸盐水泥在水化硬化过程中有微膨胀,但体积安定性满足国家相关规范要求;在煤矸石中添加少量CaO利用微波技术可获得质地优良的水泥辅助性胶凝组分;与常规热活化煤矸石方法相比微波辐照活化煤矸石的节能和生产成本降低效果十分显著。     

微波活化煤矸石对水泥基材料的性能影响

本研究采用微波对煤矸石粉进行高温辐射以激发其潜在活性,使其作为掺合料高效运用于水泥基材料中。通过红外温度仪测量煤矸石粉微波温度,进一步利用激光粒度分析、XRD和SEM对活性煤矸石粉的矿物组成和微观形貌进行表征,对比分析了未活化和活化后煤矸石胶砂的流动度及力学性能,研究了活性煤矸石粉的水化机理。结果表明：微波高温后,煤矸石粉的粒度整体减小,颗粒圆润化和粒径均匀化。此外,微波高温使得煤矸石结构疏松多孔,所需游离水增加,胶砂流动度下降。当微波温度为500～600℃,煤矸石粉掺量为10%、20%、30%时,试块的28 d抗压强度比未活化组分别提高了46.5%、37.9%、51.1%。活性煤矸石浆体中煤矸石粉表面生成了水化活性较好的C-S-H和C-A-S-H凝胶,发挥了火山灰效应,而未反应的煤矸石粉则填充在浆体空隙中,进而提高了胶砂的力学性能。     

微波辐照活化煤矸石-硅酸盐水泥体系试验研究

通过宏观试验和扫描电镜（SEM）微观测试分析技术研究了微波辐照活化煤矸石及掺量对硅酸盐水泥体系的细度、凝结时间、体积安定性、火山灰活性和强度等性能的影响，结果表明，大掺量微波辐照活化煤矸石对硅酸盐水泥体系各项技术性能无不良影响；微波辐照活化煤矸石硅酸盐水泥在水化硬化过程中有微膨胀，但体积安定性满足国家相关规范要求；在煤...     

不同温度煅烧凹凸棒土的水化活性

研究了煅烧温度(200～800℃)对凹凸棒土外观、矿物组成和活性SiO2含量的影响,煅烧前后凹凸棒土对水泥浆体化学结合水量、反应程度和水泥胶砂抗折、抗压及劈裂强度等力学性能的影响.结果表明:煅烧温度改变了凹凸棒土的矿物组成,从而影响了水泥基材料的水化活性,经500℃煅烧的凹凸棒土对水泥基材料水化活性的提高效果最佳.     

硫铝酸钙-贝利特水泥熟料的低温制备及其水化性能研究

以煤矸石、脱硫石膏、石灰为主要原料,采用水热合成-低温煅烧方法制备了硫铝酸钙-贝利特水泥熟料,通过X射线衍射(XRD)、扫描电镜(SEM)等分析了水热合成物、煅烧试样及水化产物的矿物相,利用等温量热仪测定了水泥早期水化放热随时间的变化,并测定了水泥的力学性能。结果表明:在120℃下水热合成前驱体后再经煅烧,可在1 050℃低温下制成硫铝酸钙-贝利特水泥熟料。与一步法相比,该低温水泥的早期水化放热速率较高。当水泥中的二水石膏掺量为13%(质量分数)时,水泥1d、28d的抗压强度分别为30.2 MPa和57.3 MPa,28d的水化产物主要为长纤维状的AFt。     

热激发煤矸石-水泥体系煤矸石与水泥的相互作用研究

通过对热激发煤矸石-水泥体系的水化热特征、Ca(OH)2含量、化学结合水含量以及热激发煤矸石的反应程度的研究,揭示了热激发煤矸石-水泥体系中热激发煤矸石和水泥的相互作用规律.研究结果表明,热激发煤矸石对于水泥水化的促进作用主要表现在早期,中间阶段对于水泥的水化会产生一定的抑制作用;水泥对于煤矸石的火山灰反应的促进作用则贯穿于始终.     

三元复合胶凝体系中硅灰和粉煤灰反应程度的确定

采用选择性溶解法和非蒸发水量法定量研究了不同龄期、不同掺量水泥-硅灰-粉煤灰三元复合胶凝体系中矿物掺合料的反应进程。用同细度同掺量的惰性石英粉替代粉煤灰以消除粉煤灰的稀释效应和异核成核效应,得到三元复合胶凝体系中硅灰的反应程度;根据三元复合胶凝体系中矿物掺合料的整体反应程度,计算了粉煤灰的反应程度。结果表明,硅灰的火山灰反应在复合胶凝体系水化1 d时就已经开始,并呈现早期快而后期慢的特点;而粉煤灰的火山灰效应,在7 d以后才开始并加快。在三元复合胶凝体系中,硅灰和粉煤灰的反应程度均随着粉煤灰掺量的提高而降低。     

硫硅酸钙的合成及水化性能的研究

以分析纯物料制备硫硅酸钙(C_5S_2$)矿物,通过XRD、f-CaO分析不同煅烧温度对C_5S_2$矿物合成的影响,Rietveld精修计算C_5S_2$矿物的合成率,SEM观测其形貌。将合成的C_5S_2$矿物按不同比例掺入硫铝酸盐水泥中,通过测定抗压强度及水化试样结合水含量来研究C_5S_2$矿物对硫铝酸盐水泥力学性能及水化速率的影响。研究表明:C_5S_2$矿物的最佳煅烧温度为1 150℃,合成率可达到94.9%,C_5S_2$晶体形貌为圆棒状。当C_5S_2$掺量在7.5%～10%时,水泥强度明显提高;当C_5S_2$掺量为10%时,水泥28 d强度可达到73.3 MPa。掺入适量C_5S_2$可以提高硫铝酸盐水泥的水化速率,当C_5S_2$掺量为10%时,水泥28 d结合水量达到27.48%,水化速率最高。     

高分子PVP吸附对胶体Zeta电位的影响

高分子聚合物PVP在SiO2 胶体颗粒上的吸附将直接影响胶体的稳定性质 ,其中最重要的包括Zeta电位、吸附层厚度等。从温度、pH值、聚合物浓度以及电解质浓度 4个方面考察了以上两方面的变化 ,初步探索了胶体表面Zeta电位变化的一般规律 ,并用电位法计算了胶体表面的吸附层厚度     

大尺度结构对气动光学效应影响的实验研究

为了深入研究细光束穿越可压缩混合层后光束畸变的机理,本文提出将双曝光CCD相机成像技术与纹影技术相结合进行流场与光束畸变的同步测量.利用纹影技术获得可压缩混合层密度梯度场特征,进而获得大尺度结构的密度梯度场分布;利用CCD相机成像技术获取通过混合层后光束畸变特性;双曝光技术的引入可以得到大尺度结构的移动对细光束畸变的影...     

Paramagnetic Meissner Effect

The explanation for the paramagnetic Meissner effect (PME) in high-temperature superconductors (HTSC) and niobium disks, distinct from previous discussions, is proposed. It is based on the impurity mechanism of high-temperature superconductivity and the general localization approach to the superconductivity problem. Turns of the local magnetic moments of the two-level systems are considered to be the cause of this effect in HTSC. The estimations of the magnetic moment magnitude and the magnetic moment concentration are given. In niobium disks, this effect is also explained by turns of the local magnetic moments, but of another nature. The role of the layered structure is demonstrated. It is shown that the proposed models can explain all available experimental facts. The connection between this effect and the electric field effect in HTSC is discussed.     

Wohlleben Effect (Paramagnetic Meissner Effect) in High-Temperature superconductors

Recently a quite unexpected phenomenon was observed during the study of the magnetic properties of High-T_c superconductors: In the field-cooled regime the magnetic response of some HTSC at very low fields ( 1Oe), instead of being diamagnetic, becomes paramagnetic. Such behavior is perfectly reproducible and stable. This effect is now called the Wohlleben Effect. The samples showing the Wohlleben effect also display anomalous behavior in some other properties (microwave absorption, second harmonic of magnetic susceptibility). In this paper a survey is given of the experimental studies of this and related phenomena, carried out in different laboratories. Corresponding theoretical models are also discussed. The effect is attributed to the formation of spontaneous currents (spontaneous orbital magnetic moments) in the ground state of the weak link network in case when Josephson coupling between certain grains is negative (-contacts). Microscopic mechanisms of inverse Josephson coupling are discussed especially in connection with the possible unconventional pairing in HTSC.     

Paramagnetic Meissner Effect

The explanation for the paramagnetic Meissner effect (PME) in high-temperature superconductors (HTSC) and niobium disks, distinct from previous discussions, is proposed. It is based on the impurity mechanism of high-temperature superconductivity and the general localization approach to the superconductivity problem. Turns of the local magnetic moments of the two-level systems are considered to be the cause of this effect in HTSC. The estimations of the magnetic moment magnitude and the magnetic moment concentration are given. In niobium disks, this effect is also explained by turns of the local magnetic moments, but of another nature. The role of the layered structure is demonstrated. It is shown that the proposed models can explain all available experimental facts. The connection between this effect and the electric field effect in HTSC is discussed.     

掺杂ZrO2对（Pb,Ca）（Fe,Nb）O3陶瓷微波特性的影响

研究了B位Zr掺杂对(Pb     

爆破地震效应

爆破地震震动达到足够强度时,就会引起各种破坏现象.寻找爆破地震烈度工程标准参数,研究爆破地震动强度,分析爆破地震力对结构的破坏作用,是当前工程结构抗爆破地震效应研究的重点问题.综述了爆破地震烈度的局限性,说明了爆破地震加速度和速度间的相关性,重点通过分析单质点系的爆破地震反应,计算了结构中的内力,进而判断结构的破坏情况,得出建筑结构的震害是由爆破地震运动的加速度或速度最大值决定,而岩土工程的震害主要由地面运动最大速度决定的结论.     

碘化壳聚糖-淀粉复合膜对芒果保鲜效果的研究

对壳聚糖淀粉和碘化壳聚糖淀粉复合膜的透明性、抗拉强度、伸长率、透气性、透湿性进行测试,并用壳聚糖、碘化壳聚糖与淀粉制成涂膜液对芒果进行保鲜处理,然后在常温下进行储藏.结果表明:涂膜芒果在储藏期间其感官评分、果实腐烂指数、转黄指数、失重率、呼吸强度、总糖含量的变化均小于对照组,可有效延长保质期4~6d,并且碘化壳聚糖淀粉复合膜对芒果的保鲜效果优于壳聚糖淀粉复合膜.     

锗基半导体器件的界面磁阻效应和体磁阻效应

本工作对Ag/p-Ge:Ga/Ag器件的界面磁阻和体磁阻效应进行了研究,结果表明该器件的体磁阻效应远大于界面磁阻效应.对界面磁阻而言,界面局部等离子体的形成与淬灭受外加磁场的影响较小,致使界面磁阻很小;而对体磁阻而言,磁场导致载流子复合速率加快,使载流子浓度急剧下降,从而导致体磁阻数值较大.进一步研究发现,采用低载流子浓度Ge制备的器件可以获得更为优异的体磁阻效应.本工作也研究了不同磁场施加方向对体磁阻效应的影响,发现低温时体磁阻具有明显的各向异性.当温度低于200 K时,垂直方向的体磁阻明显大于平行方向的体磁阻,其中当温度为10 K时,垂直方向体磁阻最大值约为123％@1 T,远大于平行方向的体磁阻数值(仅约为41％@1 T).机理分析认为,体磁阻效应的各向异性源于不同磁场构型下几何效应的差异,而低温下载流子迁移率的增加导致这种几何效应的影响更为明显.     

Meissner Effect, Spin Meissner Effect and Charge Expulsion in Superconductors

The Meissner effect and the Spin Meissner effect are the spontaneous generation of charge and spin current respectively near the surface of a metal, making a transition to the superconducting state. The Meissner effect is well known but, I argue, not explained by the conventional theory; the Spin Meissner effect has yet to be detected. I propose that both effects take place in all superconductors, the first one in the presence of an applied magnetostatic field, the second one even in the absence of applied external fields. Both effects can be understood under the assumption that electrons expand their orbits and thereby lower their quantum kinetic energy in the transition to superconductivity. Associated with this process, the metal expels negative charge from the interior to the surface and an electric field is generated in the interior. The resulting charge current can be understood as arising from the magnetic Lorenz force on radially outgoing electrons, and the resulting spin current can be understood as arising from a spin Hall effect originating in the Rashba-like coupling of the electron magnetic moment to the internal electric field. The associated electrodynamics is qualitatively different from London electrodynamics, yet can be described by a small modification of the conventional London equations. The stability of the superconducting state and its macroscopic phase coherence hinge on the fact that the orbital angular momentum of the carriers of the spin current is found to be exactly ?/2, indicating a topological origin. The simplicity and universality of our theory argue for its validity, and the occurrence of superconductivity in many classes of materials can be understood within our theory.