水煤浆气化炉耐火材料的损毁原因及改进

分析了水煤浆气化炉用耐火材料的损毁原因,认为熔渣侵蚀、剥落和机械磨损是导致炉衬耐火材料损毁的主要因素,其中以剥落为主;引起剥落的原因是多方面的,包括熔渣渗透引起的结构应力、温度变化引起的热应力、体积膨胀引起的机械应力及组分价态变化引起的体积效应等。以减少熔渣渗透为目的,通过添加适合金属外加剂,研制的新产品具有更高的体积密度和更小的气孔直径,预计可提高炉衬使用寿命10%以上。     

膜生物反应器膜污染泥饼层剥落研究

膜生物反应器(MBR)是一种由膜分离单元与生物处理单元相结合的水处理技术。MBR具有出水水良好,效率高等特点,成为最受欢迎污水处理工艺之一。由于MBR膜分离单元易产生淤塞造成膜污染,阻碍了其发展。膜污染是指混合液中的微粒及溶质大分子与膜存在着物理、化学或生物作用而在膜表面或膜孔内部沉积,造成膜孔变小或堵塞,进而在膜面形成泥饼层,使得膜通量减小和TMP增加的现象。因此研究膜污染泥饼层的剥落机理对MBR有重要意义。通常MBR泥饼层剥落量取决于曝气量,曝气孔径,曝气时间等。本实验表明:曝气量小,泥饼层(SS)剥落量在膜上中下三部分相差不大;曝气量大,膜下方泥饼层SS剥落大,泥饼层厚度与SS剥落一致。而胞外聚合物(EPS)(mg/gvss)是冲刷后反而增加,因为曝气只能冲刷掉SS,而作为膜污染主要因素EPS则很难去除,即曝气的剥落作用对EPS的去除不明显,得出结论物理清洗并不能有效防止膜污染。     

约束对单面盐冻混凝土表面损伤的影响及机理EI北大核心CSCD

研究约束(膨胀约束、收缩约束)对单面盐冻混凝土表面损伤的影响及作用机理,测试了水灰比为0.40的自由态和约束态混凝土每4次盐冻循环的表面剥落量和首次盐冻循环降温过程中的混凝土应变,计算了混凝土表面冰层中的拉应力。结果表明:约束态混凝土表面剥落量比自由态混凝土大;约束态混凝土表面剥落量随膨胀约束应力增大而增加,受收缩约束应力影响较小。与自由态混凝土相比,约束态混凝土表面冰层中的拉应力较大且随膨胀约束应力增大而增大;根据"粘贴-剥落"理论计算并证明了膨胀约束导致冰层更易开裂,引发了冰层下混凝土发生更严重表面损伤。     

解决膜污染技术的理论探讨

用解析的方法分析了膜作简谱振动时,膜间流体的速度场分布,用数学的形式说明了污染颗粒在膜表面受交变应力作用,从而使污染颗粒从膜表面脱离下来,产生自净效果。     

高铬耐火材料在熔渣气化炉中的剥落模式

在熔渣气化炉中,将煤转化成可燃烧洁净能源的可行性一直受到气化炉热面耐火材料使用寿命的制约。影响耐火材料使用寿命的最主要损毁机制是材料的剥落,无论是材料体积膨胀(受到压应力)或是体积收缩(受到拉应力)时都会产生剥落。对于高铬耐火材料的性能以及使用特性而言,在气化炉操作环境下,体积收缩是其损毁的基础模式。这种模式在适当情况下可以预测气化炉用耐火材料的使用寿命,如铬挥发并向表面扩散,熔渣从气孔和裂纹向材料内部渗透。     

陶瓷饮食器的釉面开裂现象和釉内应力的关系以及釉应力的快速测定方法(坯釉适应性的研究之一)

一、前言开裂是陶瓷饮食器中最为常见的一种缺陷.W、舒马赫(1876年)以及稍后的H、西格指出产生开裂或剥落主要是由于釉和坯体的热膨胀不同,使釉内产生了应力.即当釉的热膨胀系数大于坯体,冷却时釉内产生拉伸应力而形成开裂.反之当釉的热膨胀系数过小,压缩应力超过一定程度时则形成剥落.然而实际情况是釉的抗压强度要比拉伸     

B掺杂CVD金刚石厚膜的应力研究

在HFCVD系统中采用B2O3作为掺杂源制备了B掺杂CVD金刚石厚膜,利用X-射线衍射仪研究了B掺杂对CVD金刚石厚膜应力的影响.结果显示,B元素的掺杂改变了金刚石膜的成分和结构,膜中非晶态碳含量随着掺杂浓度的增加而增加.在低掺杂时CVD金刚石厚膜成核面上的应力状态为压应力,在高掺杂时应力状态为张应力,张应力值随着掺杂浓度的增加而增加.掺杂CVD金刚石厚膜生长面的应力为张应力,在高掺杂时的张应力值较高.     

复合材料联轴器膜片的应力分析

用ANSYS有限元程序对复合材料联轴器中圆环式膜片进行了应力分析,给出了膜片中存在的4种应力的计算结果,并分析比较了应力对复合膜片疲劳寿命的影响。其结果对复合材料膜片疲劳寿命的计算提供了参考。     

304不锈钢应力腐蚀的临界氯离子浓度

通过慢拉伸实验得出了304不锈钢应力腐蚀敏感性与溶液中Cl-浓度的关系,用扫描电镜对拉伸试样的断口形貌进行了分析,得出了304不锈钢发生应力腐蚀的临界氯离子浓度。采用自行设计的装置对304不锈钢试样施加拉应力,通过恒应变条件下的电化学原位测试研究了304不锈钢钝化膜破裂电位与氯离子浓度的关系。得出导致钝化膜破裂电位突变的Cl-浓度与发生应力腐蚀破裂的临界Cl-浓度是基本一致的结论。     

碳素制品抗热冲击性能的几种测定方法

一、前言碳素制品具有良好的导热性能和耐高温性能。广泛应用于各种高温领域。在使用过程中,碳素制品受到各种机械应力和热应力的冲击,易发生裂纹或破损剥落现象统称为“剥落”。由热冲击而产生的热应力,使碳素制品发生裂纹或破损,称之为“热剥落”。碳素制品在使用时,连接处,连结过紧或不好,引起不均衡的张力,剪切力而造成裂纹剥落损伤,称之为“机械剥落”。另外,碳素制品在使用时受到铁水,钢水等侵蚀而引起组织上的变化,在组织的不连续处发生裂纹剥落,称之为“组织剥落”。     

多色钛阳极氧化膜的耐蚀性研究

钛阳极氧化膜由于其特殊的性能而得到广泛作用。在此通过测量钛阳极氧化膜在０．０５ｍｏｌ／Ｌ氢氟酸溶液中的腐蚀电位随时间的变化以研究其耐蚀性。分析了膜层厚度、膜的形成温度及时间对其耐蚀性的影响。     

Ultrasonic velocity and attenuation of polymeric solids under oscillatory deformation. III: Drawn films of high density and linear low density polyethylene and their blends

Viscoelastic nonlinearity was examined on uniaxially drawn films of high density and linear low density polyethylenes and their blends using dynamic ultrasonic measurements. It was found that nonlinearity due to plastic deformations, such as slippage and dislocations, occurs in the fibrous structures. Plastic deformations were different from those in corresponding undrawn films. For undrawn films, the formation and/or deformation of crystal defects and voids were caused by the disruption of spherulitic structures. Nonlinearity was smaller for drawn films than for undrawn films, suggesting that the superstructure of drawn films is more uniform and more stable for mechanical deformations.     

Electrochemical analysis of zincate treatments for Al and Al alloy films

Electrochemical behavior of Al and Al alloy films in zincate solution was investigated to elucidate the effect of the zincate pretreatment for electroless NiP deposition, which is used for under bump metallization for LSI interconnects. The immersion potential for AlCu and AlSiCu, immediately reached to constant, which was almost equal potential to zinc reference electrode. The corrosion current for the AlCu and AlSiCu films was larger than that of the Al and AlSi films in the zincate solution. It was also confirmed that the deposited Zn at the surface of AlCu and AlSiCu films possessed smaller grain size and larger amount of nucleation, resulted in the formation of flat NiP films.     

Gas transport phenomena in hydroxypropyl cellulose solid film retaining cholesteric liquid crystalline order

Two kinds of hydroxypropyl cellulose (HPC) films were prepared: one retained cholesteric liquid crystalline order (HPC-A), and another was amorphous (HPC-B). Gas transport phenomena in the HPC-A films were determined at 20°C, which is below the T_g of HPC, compared with those in the HPC-B films, by using mainly oxygen and nitrogen gases; herium and carbon dioxide gases were also used. The permeability coefficient P for the HPC-A films was smaller than that for the HPC-B films by approximately 10 times. The gas permselectivity, defined as the ratio of P for each gas, was affected by the liquid crystalline order, as follows: The permselectivity for the HPC-A films was greater than that of the HPC-B films. The trends of gas permeability and permselectivity for the liquid crystal-forming HPC films were the same as those reported for other liquid crystal-forming cellulosic films. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1465–1470, 1998     

Comparative study of the elasticity and permeability of vulcanized films made with skim and cream natural rubber latex

The purpose of this study was to gain a clearer picture of the structure and properties of vulcanized films made with skim and cream latex from Hevea brasiliensis. The two properties targeted for this study were the elasticity of the films and their permeability to acetone. Surface characterization by atomic force microscopy revealed that vulcanization substantially modified the structure of the films compared to unvulcanized films. Unlike unvulcanized films, particle identity was retained in the vulcanized films made with cream latex, even after 4 weeks of aging. In addition, skim latex gave vulcanized films with greater elasticity than those obtained with cream latex. On the basis of the structural characterization carried out on the latex and films and information from the literature, the greater elasticity of the skim films arose from more entanglements between polyisoprene chains and associations between proteins. Despite differences in the structure, the acetone permeability was very similar for skim and cream vulcanized films. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Investigation of plasma polymerized benzene and furan thin films for application in opto‐electronic devices

Conjugated polymers are among the most promising organic materials for opto‐electronic devices. In such applications, the main fabrication problem is to get uniform, defect‐free, and reproducible thin films of these materials. In this investigation, an RF plasma reactor was used to produce cross‐linked organic thin films from benzene and furan precursors. Uniform thin films of desired thickness were fabricated using this plasma polymerization technique. The composition of the plasma‐polymerized films was determined with X‐ray photoelectron spectroscopy. Fourier transform infrared spectra of the monomers and plasma‐polymerized thin films prepared were compared to analyze the chemical structure of the films. Ultraviolet–visible absorption spectroscopy shows a red shift of 45 nm in λ_max for the case of plasma‐polymerized benzene films and 52 nm in the case of plasma‐polymerized furan films when compared to their respective monomer spectra. Photo luminescence spectra of these films show a blue emission with a broad peak at 460 nm for the plasma‐polymerized benzene films and 445 nm for the plasma‐polymerized furan films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 523–528, 2003     

锂离子电池隔膜研究与发展现状

介绍了锂离子电池隔膜的特性和类型。重点介绍了国内外聚烯烃隔膜的发展现状,通过专利和文献的检索了解到以聚烯烃为原料生产锂离子电池隔膜的发展历史和目前国外对锂离子电池隔膜开展研究较活跃的国家,最后介绍了锂离子电池隔膜的生产技术和国内市场情况,并提出了发展建议。     

Effects of mechanical properties of paint film on the forming of pre-painted steel sheets

Formability is one of the most important factors for pre-painted steel sheets (PCMs). Both high formability of the steel substrate and high integrity of the paint films on it after processing are required. In this study, elongation, tensile strength and elastic strain energy of various paint films were examined by tensile test, and the relationship between the mechanical properties of paint films and the integrity of paint films of PCM after bending and drawing were studied. We found that the required properties of paint films of PCM depended on the forming mode. In the bending mode, in which steel sheets were mainly subjected to tensile strain, the damage of paint films was dominated by the maximum strain and the tensile strength of the paint films. The paint films having higher maximum strain and higher tensile strength had better formability in bending. On the other hand, the damage of paint films was dominated by the maximum strain of paint films and elastic strain energy stored in paint films after deformation in the drawing mode in which steel sheets were subjected to tensile and compressive strain. The paint films having higher maximum strain and lower elastic strain energy had better formability in drawing. The relationship between the lubrication attributes of paint films and the limit of drawing ratio (LDR) of PCM was also studied. It was observed that the PCM with paint films having low friction coefficient had a higher LDR and it was the same ratio as the unpainted substrates.     

纳米MoS2的制备及其与聚吡咯物复合膜光学性能的研究

以有机热溶剂法制备MoS2,并以XRD对其结构进行表征.TEM形貌观察表明晶粒具有纳米尺寸。以电化方法在ITO导电玻璃基体上制备聚合物聚吡咯薄膜。在导电聚合物膜上涂布纳米MoS2晶体,荧光分析发现其荧光光谱相对于聚合物膜有一定程度的红移。Z-Scan测试其折射率的结果表明其具有非线性光学特性。     

Mechanical Properties of Sputter-Deposited Titanium-Silicon-Carbon Films

The effect of SiC additions on the mechanical properties of TiC films was investigated. Ti-Si-C films with varying SiC content were deposited using dual-cathode radio-frequency magnetron sputtering. The nanoindentation hardness of these films increased with SiC content to a maximum of 20–22 GPa for films in the range of 15–30 at.% SiC. The elastic modulus was also measured, and the hardness to modulus ratio ( H / E ) increased with SiC content, indicating that hardness increases were due to microstructural effects. The residual stress was measured in several films, but was low in magnitude, indicating that hardness measurements were not influenced by residual stress. TEM examination of several films revealed that the SiC additions altered the film microstructure in a manner that could account for the observed hardness increases.