用偏钛酸作原料制备纳米TiO2粉末以及颗粒相结构与光催化性能关系的研究

米用常温氨水水解TiOSO4过程中加入自制的表面活性剂制备了超细纳米TiO2粉末,用XRD,TEM和比表面仪对不同煅烧温度下的纳米TiO2粉末结构、粒径大小和比表面等进行了表征,研究了纳米TiO2粉末对甲基橙的光催化降解能力。研究表明煅烧温度在400℃～800℃时得到的纳米TiO2粉末呈锐钛矿结构,粒径约为5．5nm～9．6nm,比表面积高达189．45m^2/g;在850℃煅烧后所得的纳米TiO2粉末为锐钛矿与金红石型混晶结构;在l100℃时得到的纳米TiO2粉末为金红石型纳米TiO2粉末,同时微粒出现团聚且粒径变大。光催化实验表明：纳米TiO2粉末的光催化活性与煅烧温度密切相关,850℃煅烧1．5h所制得的混晶结构纳米TiO2粉末表现出较高的光催化活性。与国产商品纳米锐钛矿型TiO2相比,其降解甲基橙的速率约为国产商品纳米TiO2的1倍。     

硫化亚铜/四针状氧化锌晶须异质结的多元醇法制备及光催化性能(英文)

以聚乙烯吡咯烷酮(PVP)为表面活性剂,通过多元醇法制备 Cu2S/T-ZnOw异质结复合材料,利用 XRD、FESEM、EDS、XPS 和 FTIR 测试方法对样品进行表征,通过测定甲基橙溶液的光降解率来评价样品的光催化活性。结果表明,在紫外光照射下,Cu2S/T-ZnOw纳米复合材料的光催化性能优于纯氧化锌晶须的。当 PVP 的浓度为 3.0 g/L 时,样品的光催化活性最高,在紫外光照射 120 min 后,甲基橙的降解率为 97%。经过 4 个周期的光催化实验后,Cu2S/T-ZnOw 催化剂的光催化活性并没有明显下降,说明该样品具有优异的光稳定性。此外,讨论了Cu2S/T-ZnOw 纳米复合材料的光催化机理。     

双通TiO2纳米管阵列光催化膜的研制

采用阳极氧化法,在钛箔上制备TiO2纳米管阵列,并利用HF气体去处其阻挡层,并作了SEM,Uv-Vis表征,表明获得了具有光催化性能的双通TiO2纳米管阵列.以双通TiO2纳米管阵列为光催化剂,在紫外光照射下进行甲基橙的降解实验,2 h内甲基橙降解率可以达到86%(A=484 nm),发现其光催化降解甲基橙的效果明显较好.     

双氧水改性二氧化钛的光催化性能研究

研究了用微乳法制备纳米二氧化钛粉末的工艺，以及在紫外光照射下，TiO2和H2O2分别以及两者结合对于甲基橙溶液的降解作用。结果表明用微乳法可以制备粒度为23．2nm的纳米TiO2粉末；在紫外光照射下，H2O2可以有效地降解甲基橙溶液；当H2O2浓度从1mmol／L增加到10mmol／L，甲基橙的吸光度直线下降；当H2O2浓度达到10mmol／L时，降解率可以达到99％；TiO2也可以有效地降解甲崔橙溶液，当TiO2的浓度为0．50～0．75g／L时，降解率最大；用H2O2对TiO2进行改性后，可以有效地降解甲基橙溶液，固定TiO2的量为0．5g／L时，当H202浓度为4mmol／L时，甲基橙溶液的吸光度达到最低；当H2O2浓度处于10mmol／L以上时，甲基橙溶液的吸光度却出现无规则的变化。     

硅胶负载掺钕TiO2的制备及其光催化性能

采用溶胶-凝胶法将掺钕二氧化钛负载在二氧化硅上制备复合光催化剂（Nd/TiO2-SiO2）,利用XRD、SEM、FT-IR和DRS对Nd/TiO2-SiO2进行表征,并通过甲基橙溶液的光催化降解评价其光催化性能。结果表明：Nd/TiO2-SiO2在可见光区388-619nm范围内的光吸收性能随着钕掺杂量的增大而增强,钕掺杂有利于降低电子-空穴的复合率,钕和二氧化硅提高TiO2的光催化活性。在600℃煅烧的0.1%Nd/TiO2-SiO2的光催化活性最高,1h后甲基橙降解率为82.9%。     

氮和硫共掺杂纳米TiO2光催化剂的制备及可见光活性研究

以钛酸四丁酯、三乙醇胺和硫脲为前驱物,采用溶胶-凝胶法合成了氮硫共掺杂纳米TiO2光催化剂,以XRD、DRS、PL、FTIR、SEM、TEM、XPS等手段对所制备的粉体进行了性能表征;并以日光色镝灯为光源,研究了催化剂对光降解甲基橙的活性.结果表明,除了700℃煅烧样品是锐钛矿和金红石晶型共存外,其它掺杂催化剂主要是锐钛矿晶型.不同温度煅烧的催化剂在波长低于550nm的可见光区域内都有高的吸光度.可见光光催化结果表明,500℃煅烧制得的掺杂氧化钛光催化剂表现出最佳的光催化活性,180min内对甲基橙溶液的降解率达到76.7%.     

柠檬酸络合sol-gel法原位合成rGO-La~(3+)/TiO_2及其光催化性能

首先采用Hummers法制备氧化石墨烯(GO),然后用柠檬酸络合溶胶-凝胶法原位合成GO-La~(3+)/TiO_2,再经硼氪化钠还原得到石墨烯-La~(3+)/TiO_2(rG0-La~(3+)/TiO_2)复合材料;利用X射线衍射(XRD)、透射电镜(TEM)、荧光光谱(PL)对其进行表征分析。研究了GO加入量对复合材料光催化效率的影响及复合光催化剂投入量对甲基橙降解率的影响。结果表明:柠檬酸络合法可以有效改善纳米La~(3+)/TiO_2在rGO表面的分散情况;rG0-La~(3+)/TiO_2复合光催化剂的光催化活性明显高于La~(3+)/TiO_2,GO加入量对复合材料光催化性能影响很大;降解甲基橙时,复合光催化剂最佳投入量为0.10g。     

热处理对活性炭负载纳米TiO2光催化剂晶体结构及光活性的影响

用改性溶胶-凝胶法合成了活性炭负载纳米TiO2光催化剂粉末,通过X射线衍射(XRD)、拉曼光谱(Raman)、透射电子显微镜(TEM)等研究光催化剂的晶体结构和表面形貌。不同气氛下煅烧对TiO2的晶体转变的影响研究表明：氮气下TiO2晶体转变温度明显低于空气下晶体转变温度,但是活性炭负载量对晶体结构的影响不大。光催化活性实验表明：活性炭负载纳米TiO2光催化剂对亚甲基蓝的降解作用要优于纯TiO2的降解作用。不同气氛下煅烧实验研究发现,在低于400℃时,空气中煅烧的光催化剂的光催化活性明显要优于在氮气中煅烧的;但在400℃时氮气中煅烧后的光催化剂对亚甲基蓝的降解作用达到了最佳,且高于同温度下在空气中煅烧的样品。而高于400℃后其降解效果逐渐下降。在空气中煅烧后的光催化剂在550℃煅烧后才对亚甲基蓝的降解活性达到了最佳状态。     

纳米氧化钛粉体的制备及光催化应用的研究

利用机械力化学法成功制备了TiO2粉体.研究了外界条件(添加不同介质)对纳米TiO2晶相的影响.用XRD衍射仪对纳米TiO2粉末的微观结构、粒径大小进行了表征.同时研究了不同制备条件下的纳米TiO2粉末对甲基橙的光催化降解能力.光催化试验表明,纳米TiO2粉末的光催化活性与其晶相和煅烧温度密切相关.     

Ce改性TiO2纳米粒子的制备及光催化活性

采用浸渍法制备了Ce/纳米TiO2复合粉体,用XRD对复合粉体的晶体结构进行了表征.以紫外光照下降解甲基橙为目标,研究了Ce掺杂量和焙烧温度对Ce/纳米TiO2复合粉体的光催化能力的影响规律,并分析其机理.结果表明Ce掺杂能有效地提高纳米TiO2光催化降解甲基橙的能力,在400℃～700℃的焙烧温度下,纳米TiO2为锐钛型晶型结构,0.4%Ce(质量分数,下同)掺杂的复合粉体具有最好的光催化降解甲基橙的能力,其原因在于Ce4+掺杂有利于在TiO2纳米粒子中心和表面之间产生电势差,实现光生电子-空穴对的有效分离,因此存在一个最佳掺杂浓度使得光催化活性最高;焙烧温度对Ce/TiO2纳米复合粉体的影响依赖于Ce的掺杂量,低掺杂量时,较高的焙烧温度降解效果较好;高掺杂量时,较低的焙烧温度降解效果较好.     

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.     

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.     

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。     

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).     

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.     

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.