缺氧型钨氧化物纳/微米结构的制备及其光催化性能

通过在真空管式炉中不同条件下加热氧化钨粉末和硫粉末制备了深绿色的WO_3微米颗粒、深蓝色的WO_(2.9)纳米棒和深紫色的W_(19)O_(55)纳/微米板条,并选用亚甲基蓝溶液作为目标降解物模拟污水处理测试了材料的光催化性能。研究发现,在相同条件下,所制备的3种钨氧化物纳/微米结构中W_(19)O_(55)纳/微米板条具有最好的光催化效果,且钨氧化物纳/微米结构的光催化性能与其氧缺陷程度和比表面积有关。     

铁掺杂透辉石的光催化活性(英文)

以亚甲基蓝为光催化降解标的物,考察了在紫外可见光下掺杂Fe3+的透辉石的光催化活性。应用XRD、SEM、FT-IR和UV-visDRS等方法表征了掺杂Fe3+的透辉石的结构、组成、形貌和紫外可见光吸收能力。实验结果表明:Fe3+的掺入在透辉石内产生了一些含Fe3+的新物种,提高了透辉石的紫外可见光吸收能力;透辉石的光催化活性明显依赖于Fe3+掺入量;当Fe3+掺杂量为1.848%时,透辉石具有最高的光催化活性,光反应3h后,亚甲基蓝降解率达到95%;动力学模拟可知亚甲基蓝在透辉石上的反应遵循一级反应动力学。     

铁含量对CaTiO3-Fex光催化活性的影响

利用XRD、SEM-EDS、FT-IR光谱、UV-Vis光谱等多种方法对CaTiO3-Fex进行表征,通过测定亚甲基蓝的光催化降解率来考察铁含量对CaTiO3-Fex光催化活性的影响。结果表明,当铁含量从0增加到4.745%时,CaTiO3-Fex的化学组成几乎保持不变。但是,随着铁含量的增加,CaTiO3-Fex的光吸收能力显著增强。亚甲基蓝在CaTiO3-Fex上的光催化降解遵循一级反应动力学。基于亚甲基蓝浓度的变化及其反应动力学,CaTiO3-Fe0.474%显示出最佳的光催化活性。在紫外-可见光光照3.0 h时,亚甲基蓝在CaTiO3-Fe0.474%上的光催化降解达到100%。亚甲基蓝在CaTiO3-Fe0.474%上光催化降解的表观速率常数（kobs）为1.33 h-1,是其在CaTiO3-Fe0上光催化降解的kobs的7倍。     

CuO/石墨烯的制备及光电催化性能研究

以硝酸铜和改进的Hummers法制备的氧化石墨烯为原料,原位生长制备CuO/石墨烯。采用SEM、XRD手段对其进行表征,并在紫外光照射和外加电场条件下考察了对亚甲基蓝的催化降解效果。实验结果表明,石墨烯的加入,增强了催化剂的吸附性和导电性,外加电场的施加,使得电极-催化剂颗粒-电极之间形成三电极体系,大幅提升了CuO的催化效率。与纯的CuO相比,CuO/石墨烯对亚甲基蓝的光催化降解率从33.23%提高到91.77%,对亚甲基蓝的光电催化降解率达93.16%。     

TiO_2/石墨烯-Fe_3O_4磁性三元复合光催化剂的制备及光催化性能

以改进的Hummers法制备的氧化石墨烯为原料,采用共沉淀法获得磁性的石墨烯-Fe_3O_4载体,进而采用水热法制备出TiO_2/石墨烯-Fe_3O_4磁性三元复合光催化剂。借助X射线衍射(XRD)、扫描电子显微镜(SEM)及固体紫外-可见漫反射光谱(UV-vis DRS)对产物进行表征,并通过在紫外光和可见光下对亚甲基蓝的降解来评价复合光催化剂的催化性能及稳定性能。结果表明,Ti O_2/石墨烯-Fe_3O_4磁性三元复合光催化剂对亚甲基蓝的光催化降解符合拟一级动力学模型。该复合催化剂在紫外光和可见光下均具有较好的光催化性能,且催化活性均高于纯Ti O_2。石墨烯由于担当了载体和电子受体,增强了Ti O_2在可见光区域的吸收,能有效提高对目标污染物的光催化降解活性,同时通过添加磁性Fe_3O_4,进一步提高了其回收再利用性。     

Co_3O_4/AuPt复合材料的制备及光降解亚甲基蓝的研究

采用一步水热合成法制备了具有二维尺寸的Co_3O_4材料,再通过绿色合成法引入NaBH_4还原H_2PtCl_6、HAuCl_4,得到Co_3O_4/AuPt复合纳米材料,用扫描电镜(SEM)、透射电镜(TEM)对其结构和性能进行了表征。采用紫外-可见分光光度法对复合材料的光催化性能进行了研究。结果表明,Co_3O_4/AuPt表现出最强的光催化性能,对于3.7μg亚甲基蓝(MB),当加入的催化剂达到200μg,降解时间为6min时,其降解率可达到100%;对于1000μg 2,4,6-三硝基甲苯(TNT),当加入的催化剂达到90.9μg,降解时间为10min时,其降解率可达到100%;对于55.6μg对硝基苯酚(4-NP),当加入的催化剂达到500μg,降解时间为7min时,其降解率可达到100%;由此表明,Co_3O_4/AuPt催化剂对亚甲基蓝等环境污染物质有较强的光催化降解能力。     

纤维素/ZnO复合膜的制备及其光催化性能

为克服纳米粉体光催化剂易团聚、难回收和容易引起二次污染等缺点,采用"一步"水热法在纤维素膜表面原位生长多孔球形微纳米ZnO颗粒。利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)和热重分析仪(TG)分析了纤维素/ZnO复合膜的微观形貌、组成、晶体结构、热稳定性以及ZnO的负载量;采用紫外-可见分光光度计根据亚甲基蓝溶液的降解测试其光催化活性。结果表明:该方法可成功实现纤维素膜对ZnO颗粒的负载,且当加热时间为12h时,负载的ZnO颗粒数量多分布均匀,且为多孔球状并呈典型的纤锌矿结构。在紫外光照射下,纤维素/ZnO复合膜具有优越的光催化性能,可用于降解染料等有机物;当ZnO负载量为6 mg时,3h内亚甲基蓝的催化效率为90%。     

纳米LiInO2光催化剂的溶胶-凝胶法制备与表征

本文利用溶胶-凝胶法制备了LiInO₂纳米材料,采用X-射线衍射(XRD)、扫描电镜(SEM)和紫外-可见吸收光谱等测试手段,研究了制备条件对LiInO₂微观结构的影响因素,并以亚甲基蓝为目标降解物研究了LiInO₂的光催化性能。研究结果表明：制备的LiInO₂纳米粒子具有LiFeO₂的晶型,颗粒尺寸约50-100纳米,制备样品的焙烧温度对其结构和性能产生了明显地影响,在氙灯(300W)照射90 min条件下,纳米LiInO₂对亚甲基蓝的光催化降解率达92%,活性位点捕获实验表明光生空穴在降解亚甲基蓝的机制中占主导作用。     

锌掺杂二氧化钛的制备及其催化降解亚甲基蓝

利用溶胶凝胶法制备了锌掺杂二氧化钛,用XRD研究了合成产物的晶型,利用紫外-可见分光光度计研究了二氧化钛对亚甲基蓝的降解能力。结果表明:合成得到的二氧化钛均为锐钛矿型,少量锌离子掺杂并未改变二氧化钛的晶型。锌离子掺杂量占钛酸四丁酯(TBT)质量的1.2%时,二氧化钛的光响应范围和光催化能力均达到最大值,其中光响应范围扩大至420nm,较未掺杂样品红移接近40nm,在紫外光和自然光下240min后,对10mg/L的亚甲基蓝溶液的降解率分别达到97%和79%。     

纳米颗粒增强TiO_2涂层的制备及其防污性能

为提高二氧化钛涂层的防污性能,采用KH-550硅烷改性锐钛矿型TiO_2颗粒,并充分分散于二氧化钛凝胶涂层中。通过降解亚甲基蓝溶液、细菌贴附试验、藻类贴附试验,分别评价了涂层的光催化性能、抗菌性能及抗藻类附着性能,并利用激光共聚焦显微镜及扫描电子显微镜对藻类在涂层表面的附着情况进行分析。结果表明,添加TiO_2纳米颗粒涂层的防污性能较未添加TiO_2纳米颗粒涂层有较大程度的提高。添加粒径为5~10 nm TiO_2颗粒的二氧化钛涂层对小球藻、三角褐指藻及小新月菱形藻的附着降低率分别达到了92.1%、71.5%和62.1%,相较于纯二氧化钛涂层对3种藻类的附着降低率分别提高了29.7%、68.4%和43.5%。TiO_2颗粒的加入可以有效地提高涂层的光催化性能,光催化使得涂层具有亲水、抗菌及自清洁的性能进而有利于提高涂层的防污性能。     

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.     

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).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.