钯—丁二酮肟配合物的极谱研究

1.引言我国对极谱催化波和吸附波有大量的研究,其中不少体系已有实际应用。钯的配合物吸附波也有报道,但其检测限均在5×10~(-8)mol/L左右,选择性也不够理想。我们在研究钯与有机试剂配合物的极谱行为时发现,在碱性介质中,钯与丁二酮肟的配合物在单扫示波极谱仪上,有一灵敏的配合物吸附还原波,而在酸性介质中也可以得到一个灵敏度比较高,选择性非常好的极谱波。     

示波极谱法测定矿石中的微量铱

1 前言我们根据在示波极谱上可以得到与普通极谱同样的但更为灵敏的氢的催化波这一原理,将"盐酸—碘化钾—硫脲—碲"这一测定铱的体系用于配装新功能增进器(以下简称增进器)的JP—1A型示波极谱仪上,对体系各组份进行了试验,调整了底液各成份的用量;研究了原点电位、扫描电压速度、休止时间等对测定铱的影响;将仪器选     

酚酞示波极谱及其在痕量钌催化分析中的应用

在稀盐酸介质中酚酞于－０．５５Ｖ处产生一灵敏的单扫描示波极谱波。基于在稀盐酸介质中及１００℃下，痕量Ｒｕ（Ⅲ）对高碘酸盐氧化酚酞这一缓慢反应的强烈催化作用，用自来水冷却中止反应，采用单扫描示波极谱波研究Ｒｕ这一新的指示反应，建立检出限和测定范围分别为０．０５ｎｇ／ｍｌＲｕ的催化反应－示波极谱分析新方法，并用于实际试样分析，结果较好。     

示波极谱法测定铁矿石中铁

铁矿石中铁的测定,常采用重铬酸钾容量法,其他样品中低含量铁的测定采用示波极谱法,本文研究用示波极谱法测定铁矿石中的高含量铁取得成功。     

示波极谱法测定超痕量铱

实验发现,在25℃高氯酸介质中Ir(Ⅳ)—Ce(Ⅳ)—As(Ⅲ)催化体系中As(Ⅲ)浓度的变化可用单扫描示波极谱跟踪测量。作者采用起始速率法研究了该指示反应测定铱的各种影响因素,拟定一个测定超痕量铱的催化反应—示波极谱分析新方法。其检出限和测定范围分别为0.02ng/ml和0.04～4.0ng/ml Ir。     

镀液中金的测定

1.引言金的分析方法有重量法、发射光谱法、X光荧光法、分光光度法、原子吸收分光光度法及中子活化法等。电化学分析法虽有报道,较多的是采用示波极谱法测定,如用MIBK萃取富集,以浸腊石墨电极在示波极谱仪上测定粗铜中的痕量     

富铂、钯阳极泥中微量硒的方波极谱测定

资料中还没有见到用方波极谱法测定贵金属中微量硒的报道。我们在阳极泥的分析中采用方波极谱测定微量硒时发现,铂、钯的存在严重干扰硒的测定,采用砷共沉淀或硫酸肼沉淀,都不能使硒与大量铂、钯分离。资料[1～3]介绍,溴化硒能被苯、甲苯或     

痕量钌的催化反应—示波极谱分析

实验发现,在25℃硫酸介质中,Ru(Ⅲ)对KIO_4氧化罗丹明B这一缓慢反应具有极强的催化作用,罗丹明B的氧化产物于-0.40 V产生一示波极谱波。作者以罗丹明B的电活性氧化产物作检测组分,采用固定时间法,拟定了一个检出限和测定范围分别为0.05ng/ml和0.1～2.5ng/ml Ru的催化反应—示波极谱分析新方法。该法已用于合成试样及氯化渣试样中痕量钌的分析。     

Ag(Ⅰ)—d''''d′-dipy—Na_(2)S_(2)O_8——碱性藏红T新体系的极谱研究

碱性藏红T在0.20mol/L醋酸钠介质中于-0.58V产生一双电子可逆吸附波。基于Ag(I)对Na_2S_2O_8氧化碱性藏红T这一褪色反应的强烈催化作用及联吡啶对Ag(I) 的活化作用,用示波极谱仪监测其浓度之变化,建立一个检测限和测定范围分别为2.0ng/ml和4.0～160ng/ml银的催化反应极谱法,并用于废水中微量银的测定。     

阳极溶出伏安法测定微量铱

1.引言对于微量铱的电化学测定,一般采用极谱催化波法和示波极谱法,其灵敏度分别达10~(-10)mol/L和<10ppm。由于铱的电化学活性较差,阳极溶出法测定灵敏度仅有1μmol/L,作者曾用三烷基氧化膦分离Rh-Ir,效果很好。本文将其用于贵金属复杂样品进行分离富集,达到了排除干扰的目的。同时,讨论了用阳极溶出伏安法测定微量铱的新体系。     

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.