热活化黄土胶凝性能研究

借助TG、DTA、XRD等手段研究了黄土在100 ℃～1000 ℃的物相组成和热分解特征,采用凝石技术制备了以黄土为主要原料的胶凝材料,测定其力学性能并研究了赤泥掺量对其胶凝材料的力学性能影响.研究结果表明,黄土在600℃煅烧胶凝性能良好;黄土掺量达到40%时,可获得28 d抗压强度超过42.5 MPa的胶凝材料.而且赤泥的掺入对胶凝材料的早期强度有良好的改善作用.     

热处理温度对赤泥胶凝活性的影响

通过对不同温度煅烧的赤泥特性的研究,分析了热处理温度对赤泥胶凝性能的影响。采用XRD、DSC-TG、FT-IR等测试手段对不同温度煅烧的赤泥及其水化浆体进行研究。结果表明,热处理过程中赤泥的晶相组成发生变化;800℃煅烧的赤泥中β-C2S含量明显增加,含铝矿物的铝由四配位部分向六配位转化;不同温度煅烧的赤泥胶凝活性:600℃煅烧的赤泥>未处理赤泥>800℃煅烧的赤泥。     

机械力化学效应对赤泥结构特性和胶凝性能的影响

依据机械力化学原理，采用高能球磨技术对煅烧赤泥进行了活化处理，并利用SEM、XRD、XPS、NMR等一系列微观测试分析工具对赤泥活化前后细度变化、矿物组成、微观结构以及化学状态等进行了研究，在此基础上阐明了机械力化学效应对赤泥结构特性和胶凝性能的影响。该原料条件下，配加50％粉磨时间为30min赤泥的胶凝材料强度性能达到了42．5^#水泥强度性能的要求，这为赤泥的高效大宗利用提供了试验依据和理论基础。     

矿物掺合料、纳米SiO2和纳米CaCO3对胶凝材料需水量的影响

通过粉煤灰、矿粉、硅灰、纳米CaCO3和纳米SiO2以不同掺量等量取代的方法掺入胶凝材料,通过标准稠度用水量的方法研究了胶凝材料需水量的变化.结果表明:掺入粉煤灰、硅灰、纳米CaCO3和纳米SiO2使胶凝材料的需水量增大,并随掺量的增加而增大,矿粉则相反.掺量小于8%的硅灰对胶凝材料的需水量影响不大.掺入纳米材料,掺量小于2%时,胶凝材料的需水量变化不大,掺量大于5%后,会产生急剧增大的现象.     

复合热活化对赤泥-煤矸石胶凝性能的影响

研究了600 ℃简单热活化和复合热活化对赤泥-煤矸石胶凝性能的影响,借助ICP、XRD、SEM等微观测试手段对两种活化方式下的赤泥-煤矸石体系的硅铝离子的溶出特性、矿物组成及微观结构进行了对比研究.结果表明,复合热活化之后的赤泥-煤矸石体系的胶凝性能明显提高.复合热活化过程中,赤泥的适量加入有助于房山煤矸石中绿泥石矿物的分解,且使石英的结晶度明显降低.当赤泥与煤矸石的比例为3:2,掺量为50%时,其复合体系所制备的胶砂试块28 d强度达到37.3 MPa.这为赤泥和煤矸石的大宗高效利用提供了试验依据和理论基础.     

机械力化学效应对赤泥结构特性和胶凝性能的影响

依据机械力化学原理,采用高能球磨技术对煅烧赤泥进行了活化处理,并利用SEM、XRD、XPS、NMR等一系列微观测试分析工具对赤泥活化前后细度变化、矿物组成、微观结构以及化学状态等进行了研究,在此基础上阐明了机械力化学效应对赤泥结构特性和胶凝性能的影响.该原料条件下,配加50%粉磨时间为30 min赤泥的胶凝材料强度性能达到了42.5#水泥强度性能的要求,这为赤泥的高效大宗利用提供了试验依据和理论基础.     

大掺量拜耳法赤泥轻质保温陶瓷材料的研究

大掺量拜耳法赤泥轻质保温陶瓷材料的制备以拜耳法赤泥、玻璃粉为原料,钾长石粉为助溶剂,聚苯乙烯为发泡剂。研究了不同批次赤泥对材料性能的影响,并对其微观结构和物相进行了分析。结果表明:赤泥掺量为70%、烧成温度为1060℃时,轻质保温陶瓷材料性能良好(容重为346kg/m~3,热导率为0.09W/m·℃,抗压强度为0.41MPa,不燃性属于A1级,可切可钻)。     

烧结法赤泥胶凝性能的试验研究

通过复合激发的方法，使烧结法赤泥的活性得到充分发挥。可以将赤泥配制成无熟料的且具有一定强度的水硬性胶凝材料。按照《水泥胶砂强度检验方法》（GB／T17671-1999），无熟料赤泥胶砂的3d抗折强度为2.9MPa、抗压强度为11.6MPa；28d抗折强度为6.2MPa、抗压强度为36.0MPa。     

碱激发赤泥胶凝材料的探索研究

以开发利用赤泥为目的,充分利用赤泥中2CaO.SiO2的活性成分,并对赤泥进行焙烧活化处理,再引入高活性的水淬粒化高炉矿渣组分,配以适宜的碱激发剂、调凝剂,研制成功新型碱激发赤泥胶凝材料。     

赤泥基胶凝材料的Na~+固化机理

采用SEM、EDS等分析手段研究了赤泥基胶凝材料的水化过程.结果表明,在低Ca/Si的赤泥基胶凝材料水化过程中,在Al对Si的取代作用下,桥[SiO_4]、[AlO_4]四面体数目逐渐增多,[Si(Al)O_4]结构单元聚合度逐渐增大,Si以Q~1、Q~2结构形式存在的C-S-H凝胶,逐渐转变为具有SiQ~2、SiQ~3和SiQ~4结构单元的(Na,Al)-C-S-H凝胶,从而使Na~+以化学吸附和化学固溶形式固化于水化产物中.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.