Magnetostriction of Fe81Ga19 oriented crystals

The effect of the orientation on the magnetostriction in Fe₈₁Ga₁₉ alloy has been investigated experimentally and theoretically. The Fe₈₁Ga₁₉ [001] and [110] oriented crystals were prepared and the magnetostriction was measured under different pre-stress. The saturation magnetostriction of the [001] oriented crystal increases from 170×10^-6 to 330×10^-6 under the pre-stress from 0 to 50 MPa. The [110] oriented crystal has a saturation magnetostriction from 20×10^-6 to 140×10^-6 with the compressive pre-stress from 0 to 40 MPa. The magnetostriction of [001] and [110] oriented crystals has been simulated based on the phenomenological theory. The domain rotation path has been determined and the resultant magnetostriction calculated under different pre-stress. The experimental and simulated results both show that the [001] oriented crystal exhibits better magnetostriction than [110] oriented crystal. The enhancement of the saturation magnetostriction by the compressive pre-stress in the [110] oriented crystal is higher than that in the [001] oriented crystal.     

新疆金山金矿床中Cu-Zn合金矿物的发现及其地质意义

在研究新疆金山金矿床物质组分的过程中,通过对矿石矿物进行反光显微镜下观察与电子探针分析,发现了Cu-Zn合金矿物。与国内外已发现的Cu-Zn合金矿物相比,所发现的Cu-Zn合金矿物中Cu含量(81.35%～85.36%,平均83.75%)较高,Zn含量(6.08%～10.10%,平均为7.39%)较低,并含少量的Sn(4.13%～6.75%,平均为5.23%)、Ni(0.88%～1.38%,平均为1.05%),属于为α相Cu-Zn合金矿物。Cu-Zn合金矿物在自然界极为罕见,其生成条件也很独特。结合金山金矿成矿特征和形成条件,作者认为该Cu-Zn合金矿物是在热液成矿晚阶段(第Ⅳ阶段)强还原条件下的缺氧、缺硫环境中形成的。     

基于硫酸盐还原菌作用的油菜秆固定床处理模拟含Cr（Ⅵ）废水

探讨了固定床除Cr工艺以油菜秆为微生物生长的缓释碳源,含SRB的混合微生物和油菜秆对Cr（Ⅵ）的还原和固定的共同作用。动态实验分2阶段开展：初始2周的驯化阶段和梯度增加Cr（Ⅵ）浓度的除Cr实验阶段。除Cr实验中,间歇对固定床出水pH、氧化还原电位、SO42-及硫化物浓度、DOC、Cr（Ⅵ）浓度进行测试,实验结束后对固定床中固体产物进行SEM、EDS和XPS等分析。结果表明,油菜秆固定床处理模拟含Cr（Ⅵ）废水效果明显。当进水Cr（Ⅵ）浓度ρ[Cr（Ⅵ）]〈19.52 mg/L时,出水Cr（Ⅵ）和Cr（Ⅲ）浓度均低于排放标准（0.05 mg/L）;Cr（Ⅵ）被还原为Cr（Ⅲ）,Cr（Ⅲ）以氢氧化物的形式沉淀附着于油菜秆和其它固体物质之上。分析认为,油菜秆在固定床处理模拟含Cr（Ⅵ）废水中所起的作用主要包括3方面（作为微生物生长的缓释碳源;吸附Cr（Ⅵ）,降低其对微生物的毒性;作为Cr（Ⅲ）矿化产物的沉淀附着界面）;Cr（Ⅵ）主要通过SRB的直接作用及H2S的作用被还原为Cr（Ⅲ）;以油菜秆为碳源的固定床处理Cr（Ⅵ）的浓度上限介于15.05～19.52mg/L之间。     

氧分压对Ni-Cr-Fe合金氧化成膜特性影响的研究

以铸态Ni-Cr-Fe合金为试样,于1 050℃湿氢气氛下恒温氧化20 h。通过氧化增重、SEM/EDS以及薄膜X-射线衍射等方法研究了氧分压对该合金在弱氧化性气氛下氧化成膜特性的影响。结果表明:表面氧化膜从外到内氧化物组成依次为:MnCr2O4、Cr2O3以及SiO2。氧化膜的厚度、组成及形貌与体系的氧分压密切相关,中等氧分压(15.9×10-18atm)有利于表面尖晶石的形成;较低氧分压有利于形成厚而多孔的氧化膜,而高氧分压则趋向于形成薄而致密的氧化膜。     

Phase relations of iron and iron–nickel alloys up to 300 GPa: Implications for composition and structure of the Earth's inner core

We have investigated the phase relations of iron and iron–nickel alloys with 18 to 50 wt.% Ni up to over 300 GPa using a laser-heated diamond-anvil cell. The synchrotron X-ray diffraction measurements show the wide stability of hcp-iron up to 301 GPa and 2000 K and 319 GPa and 300 K without phase transition to dhcp, orthorhombic, or bcc phases. On the other hand, the incorporation of nickel has a remarkable effect on expanding the stability field of fcc phase. The geometry of the temperature–composition phase diagram of iron–nickel alloys suggests that the hcp–fcc–liquid triple point is located at 10 to 20 wt.% Ni at the pressure of the inner core boundary. The fcc phase could crystallize depending on the nickel and silicon contents in the Earth's core, both of which are fcc stabilizer.     

石墨炉原子吸收光谱法测定镁基合金中的铍和镍

采用石墨炉原子吸收光谱法测定镁基合金中的铍和镍.研究并校正了基体对待测元素的影响.方法简单、快速.对含铍11.4×10^-6、镍9.25×10^-6的样品11份测定,相对标准偏差分别为3.5%、4.3%,铍、镍回收率分别为98.8%、97.5%.     

氢化物原子荧光光谱法测定富马酸中的砷

用氢氧化钠溶液分解富马酸使其转化为水溶性富马酸钠 ,然后用氢化物发生 -原子荧光光谱法测定了试样中的砷。方法的检出限为 0 .2 μg/L ,对富马酸中As的测定结果与国标法结果相符 ,对w(As) =1 .5× 1 0 - 6的试样测定 1 2次 ,RSD为 4.8% ,加标回收率为 97.9%～ 1 0 7.5%。     

块金成因新见及其分级

本文描述了块金的形成新机制。在热液中呈金氢化物、金羰基化合物及纳料金粒子、纳米金合金粒子活化迁移。在表生条件下,金硫代硫酸盐配合物、金粒子、金合金粒子是金迁移的主要形式。块金是地质的、化学的、物理的、生物化学的综合作用的结果。按块金成因分为内生块金和次生块金。按单块块金质量分为４级。     

The region of Collinder 121

The distribution of bright B-type stars in a field with a radius of 5° centred at the Galactic open cluster Cr 121 is studied utilizing Strömgren and H β photometry. All PPM stars earlier than spectral type A0 are used, revealing a loose nearby structure at a distance of 660–730 pc, and a compact more distant group, which appears to be a genuine cluster: Cr 121. Based on similar coordinates, distances and positions on the colour–magnitude (CM) and Hertzsprung–Russell (HR) diagrams, 11 photometric cluster members are selected at a mean distance of 1085(±41 standard error) pc. The results are discussed in the light of both classical and Hipparcos points of view.     

Chromium(VI) reduction by sulphur(IV) in aqueous solutions

The rates of the reduction of Cr(VI) with S(IV) were measured in deaerated NaCl solution as a function of pH, temperature and ionic strength. The rates of the reaction were found to be first order with respect to Cr(VI) and second order with respect to S(IV), in agreement with previous results obtained at concentrations two order higher than the present study. The reaction also showed a first-order dependence of the rates on the concentration of the proton and a small influence of temperature with an apparent energy of activation ΔH_app of 22.8 ± 3.4 kJ/mol. The rates were independent of ionic strength from 0.01 to 1 M. The rate of Cr(VI) reduction is described by the general expression

−d[Cr(VI)]/dt=k[Cr(VI)][S(IV)]²