浮选吸光光度法测定钯

1.引言浮选吸光光度法为铂族元素的分析提供了许多高灵敏度的测定法。钯—硫氰酸盐一次甲基蓝(MB)—苯体系浮选光度法采用低酸度(pH 1～6)介质,ε_(660)nm=1.7×10~5,Pd∶SCN~-∶MB=1∶4∶2。缺点是浮选物疏松,易造成损失;空白不稳定,影响测定的精密度。我们利用上述体系,采用高酸度(1.5 N HCl)介质和两次洗净技术,所得浮选物致密,空自很低而且稳定,ε_(660) nm=1.9×10~5,Pd∶SCN~-∶MB=1∶5∶3,含钯0.04～0.8μg/ml符合比尔定律。用于矿石和阳极泥中微量钯的测定效果满意。     

铑四元配合物的生成及其分光光度特性

1.引言铑在SnCl_2的HCl介质中,生成红色三元配合物〔 Cl Cl Rh SnCl_3 SnCl_3 〕-.本文在此基础上研究了Rh(Ⅱ)-SnCl_2-HCl-R(R=R6G)体系.实验证明,在1.2～3.2mol/L HCl介质中,生成紫红色四元配合物,其组成比1∶2,稳定达48h,配合物的吸收峰为560nm,试剂为520nm.采用差示双波长分光光度分析法,可在某些铂族离子的存在下,直接测定Rh含量.     

新型Gemini阳离子捕收剂对一水硬铝石和高岭石的反浮选行为

研究了Gemini 12-4-12对一水硬铝石和高岭石的浮选行为,在中性介质(pH7～pH8)下,对一水硬铝石与高岭石的反浮选分离作了初步探讨.浮选结果表明:Gemini 12-4-12在广泛的pH范围内对一水硬铝石和高岭石具有很强的捕收能力,在中性体系(pH7～pH8)及浓度3.0×10~(-4)mol·1~(-1)时,对一水硬铝石和高峰石的浮选回收率达到95%以上;在可溶性淀粉浓度为200mg/l的条件下,一水硬铝石全部被抑制,而且两种矿物回收率相差达70%以上,并且通过人工混合矿试验,对不同A/S的一水硬铝石和高岭石人工混合矿取得很好的分离效果.     

深冷处理对TC6钛合金热导率和热膨胀系数的影响

对TC6钛合金进行深冷处理,通过对比深冷处理前后合金在25～600℃范围内的热导率和热膨胀系数的变化,探讨了深冷处理对TC6钛合金热导率和热膨胀系数的影响。结果表明:随着温度升高,经深冷处理合金的热导率先小于后大于未经深冷处理合金的热导率,而热膨胀系数则先略大于后小于未经深冷处理合金的热膨胀系数。600℃时,经深冷处理合金的热导率和热膨胀系数分别为7.95 W·m~(-1)·K~(-1)和1.17×10~(-5)·℃~(-1),较相同温度下未经深冷处理的分别增大和减小了14.88%(1.03 W.m~(-1)·K~(-1))和1.62%(0.19×10~(-6)·℃~(-1))。     

镁的精炼、高纯镁的制取、镁及其合金制品和半成品的生产

工业制取的镁平均含有,％:Fe 0.03;Si 0.002;Al 0.01;Ni 0.0005;Cu 0.002;Mn 0.01;Cl 0.003;Zn 0.005;Pb 0.002;Ca 0.002;Cr(0.5～1.3)×10~(-4);Ti(1～8)×10~(-4);Sb(7～9)×10~(-6);Cd(0.5～1.2)×10~(-5);P(1～4)×10~(-3);As(1.5～3.0)×10~(-4);N(0.5～2)×10~(-3);C(1～4)×10~(-3);O(2～4)×10~(-2);以及Bi、Cs、Co各约10~(-3);Sn和Rb各为5×10~(-4);Sn、Ba、Mo、Ag、Sr、W各为1×10~(-4);Hf2×10~(-4)。镁中金属夹杂物主要来源于盐类原料、炉衬和电极材料。大气中的氧、氢和氮也会进入     

钯—氯化亚锡—孔雀绿高灵敏度离子缔合显色反应的研究与应用

研究了钯-氯化亚锡-孔雀绿高灵敏测定钯的分光光度法.在0.27～0.37M盐酸介质中,在聚乙烯醇存在下,钯氯化亚锡络阴离子与孔雀绿阳离子形成可溶的显色离子缔合物,其最大吸收值λ_(max)=700nm,ε=2.3×10~6l·mol·~9-1)·cm~(-1)钯量在0～1.0μg/25ml遵守比尔定律.并测定缔合物的组成和缔合常数,缔合物的化学式为MG_4~+[PdCl_2(SnCl_3)_4]~(4-),测定0.4～1.2μg/25ml的钯,相对标准偏差≤10%,还研究了共存离子的影响.本方法已成功的应用于矿样中痕量钯的测定.     

钢板阵列射流冷却过程换热实验研究

基于组合式超快速冷却测试装置,研究了8.4×10~5、14.0×10~5、19.6×10~5 L·(m~2·min)~(-1)水流密度对50 mm厚AISI304奥氏体不锈钢0.1 m·s~(-1)辊式淬火过程中厚向截面冷却速度和表面换热的影响,利用导热微分方程及反传热求解方法,计算钢板表面热流密度分布。结果表明,在冷却速度增长区,水流密度通过影响温度梯度的分布进而影响冷却速度变化;在平缓区,温度梯度的改变基本不受水流密度变化的影响,而是由遗传效应主导的;8.4×10~5 L·(m~2·min)~(-1)水流密度条件下的沸腾曲线能观察到明显的膜沸腾和热流肩现象,随着水流密度增加到14.0×10~5 L·(m~2·min)~(-1)和19.6×10~5 L·(m~2·min)~(-1),实验钢板表面在射流水的冲击下无法形成稳定的沸腾蒸汽膜,较高的表面温度也使得临界热流密度值增加到无法到达的水平,沸腾过程无法出现热流肩。     

焊接名词术语(五)

2·32 阴极区 cathode rogion 电弧紧靠负电极的区域。阴极区很窄,约为10~(-5)～10~(-6)厘米。 2·33 阴极压降 cathode drop 电弧阴极区两端的电压降。 2·34 阴极斑点 cathode spot 电弧放电时,负电极表面上集中发射电子的微小区域。该区域具有明显的光的斑点。 2·35 阳极区 anode region 电弧紧靠正电极的区域,阳极区较阴极区宽,约为10~(-3)～10~(-4)厘米。 2·36 阳极压降 anode drop 电弧阳极区两端的电压降。 2·37 阳极斑点 anode spot 电弧放电时,正电极表面上集中接收电子的微小     

不同壳层厚度Au@SiO_2的表面增强拉曼效应

通过电偶置换反应制备了尺寸在30~35 nm的结晶性良好的Au纳米颗粒,并成功在其表面包覆了不同厚度的Si O2壳层,利用TEM、HRTEM和UV-Vis对样品的结构和形貌进行了表征,并以罗丹明6G(R6G)为探针分子,对Au@SiO_2复合粒子的表面增强拉曼散射(SERS)效应进行了研究。结果显示,相对于Au纳米颗粒,Au@SiO_2复合粒子显著提高了拉曼信号的质量和检测的灵敏度,且Si O2壳层厚度对其SRES效应影响显著,壳层厚度为2 nm的复合粒子对R6G分子的检测极限可达10~(-7)mol/L。     

正十六硫醇分子在Ag表面的自组装动力学及其保护作用

利用充放电电容法、接触角测量法和电化学阻抗法研究了正十六硫醇在Ag镀层表面的自组装行为。在浓度为10和100μmol·L~(-1)条件下,由充放电电容法得到吸附速率常数分别为(1.3±0.2)×10~6和(2.8±0.5)×10~4mol~(-1)·L·s~(-1),由接触角方法得到的吸附速率常数分别为(9.3±0.7)×10~5和(3.4±0.6)×10~4 mol~(-1)·L·s~(-1),两种方法得到的结果一致。同时,结果也表明低浓度的硫醇分子有更高的吸附速率常数。Tafel极化曲线表明,经5 mmol·L-1的正十六硫醇溶液浸泡15 min后,Ag镀件在阴极和阳极区域的电流密度显著降低,缓蚀率可达98.6%。80°C下烘烤12 h实验、Na_2S溶液腐蚀实验以及H_2S气体腐蚀实验的结果进一步证实上述保护工艺既符合生产操作要求,又可以获得显著的耐蚀效果。     

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.     

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.     

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.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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