2-羟基萘-1-亚甲基若丹宁光度法测定铂的研究

分光光度法是测定痕量铂最广泛使用的方法之一,若丹宁类试剂是优良的显色剂。作者合成了一种新型若丹宁显色剂—2-羟基萘-1-亚甲基若丹宁(HNR),研究了HNR与Pt的显色反应,在HCl介质中,吐温-80存在下,HNR与Pt反应生成2:1稳定络合物,体系的λmax=540nm,摩尔吸光系数ε=1.02×105L·mol-1·cm-1。铂含量在0.05～2.0μg/mL内符合比尔定律,本方法可用于催化剂中铂的测定,结果满意。     

DBC-偶氮氯膦固相光度法测定痕量镧

在0.5 mo1·L-1盐酸介质中,La(Ⅲ)-(DBC-偶氮氯膦)所形成的络合物可吸附到201×7型苯乙烯阴离子树脂上.该固相显色体系最大吸收波长位于650 nm,镧的表观摩尔吸光系数为ε650nm=2.08×l05L·mol-1·cm-1.该固相分光光度法测定镧灵敏度为La(Ⅲ)-(DBC-偶氮氯膦)液相分光光度法灵敏度的2.31倍.镧在0～0.44 μg.ml-1范围内遵守比尔定律.考察了26种共存离子对测定镧的影响.本研究所建立的方法已成功地用于分子筛中镧的测定,结果满意.     

用DSPCF分光光度法测定钯

在室温下以硝酸为介质,钯与DSPCF形成有色络合物,其表观摩尔吸光系数ε_(520)=1.2×10~4,络合物组成为Pd(Ⅱ):DSPCF=1:2。其特点是在室温下发生显色反应,当加入HNO_3使介质达1.75N时,只有Pd(Ⅱ)—DSPCF红色络合物不褪色,可用于铂钯二次精矿等的测定。     

4-羟基萘-1-亚甲基若丹宁柱前衍生高效液相色谱法测定Pt、Pd、Rh

研究了用4-羟基萘-1-亚甲基若丹宁(HNR)为柱前衍生试剂,安捷伦ZORBAXStableBound(4.6×50mm,1.8μm)快速分离柱为固定相,62%的甲醇(内含0.5%的醋酸)为流动相,高效液相色谱分离,二极管矩阵检测器检测Pt、Pd和Rh的方法。3种贵金属离子的络合物在2.0min内可达到基线分离。根据信噪比(S/N=3)测得各金属离子的检测限分别为:Pt1.0μg/L、Pd0.6μg/L和Rh0.8μg/L,方法用于废汽车尾气催化剂中痕量Pt、Pd和Rh的测定,相对标准偏差为1.8%～2.1%,标准回收率为97%～103%,结果令人满意。     

4,4′-二-(二乙氨基)-苯硫酮和Triton X-100分光光度测定钯

1.引言4,4′-二-(二甲氨基)苯硫酮(简称硫代咪嗤酮)与钯(Ⅱ)的显色反应早有研究。新近有人合成了4,4′-二-(二乙氨基)苯硫酮(缩写名 BDTBP)并用于金的分光光度测定。该试剂与钯(Ⅱ)的反应未见报道。我们广泛地研究了 BDTBP 与贵金属的显色反应,发现在一定条件下 Pd~(2+)—BDTBP—Triton X-100三元体系的显色反应具有很高的灵敏度(ε=2.1×10~5l·mol~(-1)·cm~(-1))和选择性。本文系统地研究了钯有色络合物的形成条件及性能,拟订了在水相直接测定痕量钯的分光光度法,并试用于     

新显色剂2—[2,3,5—三氮唑]—5—[（N,N—二羧基甲基）氨基]苯甲酸的合成及其与钯的显色反应

合成了新显色剂 2 -〔2 ,3,5-三氮唑〕 - 5-〔(N ,N -二羧基甲基 )氨基〕苯甲酸 (简称TZACAB) ,并研究了性质及其与Pd显色反应的条件。结果表明 :试剂的分子式C1 3H1 2 N6O6,分子量 349 2 7;在pH 3 1 8HAc -NaAc缓冲溶液中 ,试剂与Pd形成 1∶1蓝色络合物 ,λmax为 661 4nm ,Pd量在 0～ 1 2 μg·ml- 1 范围内遵守比耳定律 ,表观摩尔吸光系数为ε =1 72× 1 0 4 L·mol- 1 ·cm- 1 ,大量的其它金属离子共存时 ,不经预分离也无需掩蔽剂可直接测定Pd -Pt催化剂中的微量Pd ,操作简便 ,结果满意     

偶氮氯膦Ⅲ高灵敏分光光度法测定钛

详细地研究了显色剂偶氮氯膦Ⅲ与Ti(Ⅳ)的显色反应和所形成的络合物,该络合物的λmax=690nm,表观摩尔吸光系数为1.47×105L·mol-1·cm-1,钛在0～1.0μg/ml内服从比尔定律,所拟定的方法能满意地用于还原用铁粉、粉末冶金铁粉和钢铁中微量钛的分光光度测定。     

2-(2-喹啉偶氮)-1,3-二氨基苯光度法测定钯的研究

合成了新试剂2-(2-喹啉偶氮)-1,3-二氨基苯(QADAB),并研究了其与钯的显色反应,在0.2～3.0mol/LHClO4介质中,QADAB与钯反应生成2:1稳定络合物,体系λmax=590nm,ε=8.08×104L·mol-1·cm-1。钯含量在0.01～1.2mg/L内符合比尔定律。本方法用于一些含钯样品中钯含量的测定,结果令人满意。     

5,7-二溴〔杯(4)芳烃偶氮〕氨基喹啉与Pd(Ⅱ)显色反应的研究与应用

合成了新试剂 5 ,7-二溴〔杯 ( 4 )芳烃偶氮〕氨基喹啉 (DBCAQ) ,经红外光谱、元素分析和薄板层析检验其结构。研究了该试剂与Pd(Ⅱ )的显色反应的适宜条件。在pH =5 0的HAc -NaAc缓冲溶液中及非离子表面活性剂吐温 - 80存在下 ,试剂与Pd(Ⅱ )生成 1∶1的稳定配合物 ,建立了测定Pd(Ⅱ )的光度法新体系 ,该体系至少可稳定 1 0h ,λmax=680nm ,ε =8 2 6× 1 0 4 L/mol·cm ,Pd(Ⅱ )浓度在 0～ 35 μm/2 5ml内服从比耳定律。方法已用于钯催化剂中Pd(Ⅱ )的测定 ,结果与原子吸收法 (AAS)结果相符。     

2-羧基苯偶氮若丹宁固相萃取分光光度法测定Au的研究

研究了2-羧基苯偶氮若丹宁与Au的显色反应,在HCl介质中,乳化剂-OP存在下,CPAR与Au反应生成2∶1稳定络合物,络合物的λmax=510nm,ε=7.20×104Lmol-1cm-1,Au的含量在0～20μg/10mL内符合比尔定律,矿石样中的Au用磷酸三丁酯萃淋树脂固相萃取柱分离和富集后用该方法测定,相对标准偏差为2.5%～3.2%,标准回收率为96%～103%,结果令人满意。     

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.