电感耦合等离子体质谱法测定核级海绵锆中痕量硼

硼的存在会严重影响核级海绵锆的中子平衡和反应堆的正常运转,因此,需要准确测定核级海绵锆中痕量硼。在采用电感耦合等离子体质谱法(ICP-MS)测定核级海绵锆中痕量硼时,锆基体干扰比较严重,必须对其进行校正或消除。实验用硝酸和氢氟酸溶解样品,以¹¹B为测定同位素,采用标准加入法克服基体干扰,建立了ICP-MS测定核级海绵锆中痕量硼的方法。结果表明,在优化的实验条件下,硼质量浓度在0.50~10.00 μg/L范围内与其对应的信号强度呈线性关系,相关系数为0.999 5,方法检出限为0.038 μg/g,定量限为0.125 μg/g。按照实验方法测定6个核级海绵锆样品中硼,结果的相对标准偏差(RSD)为2.3%,加标回收率为102%;采用分光光度法进行方法对照试验,两种方法测定结果基本一致。     

电感耦合等离子体原子发射光谱法测定石灰性土壤中有效磷

石灰性土壤中有效磷的测定通常采用钼锑抗分光光度法,操作复杂、检出限高。采用碳酸氢钠浸提-基体掩蔽结合电感耦合等离子体原子发射光谱法(ICP-AES)实现了对大批量土壤样本中有效磷的高效分析。实验中采用pH值为8.5、0.5 mol/L碳酸氢钠溶液为浸提液,按照20∶1的水土比(浸提液体积(mL)与土壤质量(g)之比)于(25±1)℃下振荡提取30 min;用定量滤纸过滤后,分取20.00 mL滤液,加入2 mL 硝酸(1+1)酸化,用250 mg的丁二酸掩蔽碱金属离子,选择P 214.914 nm为分析谱线,采用ICP-AES测定磷。结果表明,磷质量浓度与其发射强度在一定范围内呈良好的线性关系,线性相关系数为0.999 7。方法检出限为0.004 6 mg/kg,定量限为0.015 mg/kg。方法用于测定土壤标准物质(GBW07413a、GBW07414a、GBW07459、GBW07460、GBW07461)中有效磷,测定值与认定值基本相符,测定结果的相对标准偏差(RSD, n=6)为0.87%~2.1%;用于土壤样品中有效磷的测定,测定结果的相对标准偏差(n=6)不大于1.7%,与农业部标准方法(NY/T 1121.7—2014)测得的结果基本一致,无显著性差异。     

高分辨电感耦合等离子体质谱法测定高纯镍中25种痕量元素

镍基高温合金广泛应用于航空发动机的热端部件,其主要原材料高纯镍的纯度对其性能有着重要影响,因此需要测定和控制高纯镍中痕量元素的含量。通过选择合适的同位素克服质谱干扰,选择标准加入法绘制校准曲线克服基体效应,对辅助气流量进行了优化,在高分辨率模式下测定钙和砷,在中分辨率模式下测定其余元素,建立了高分辨电感耦合等离子体质谱法测定高纯镍中镁、铝、磷、钙、锰、铁、铜、锌、镓、锗、砷、硒、银、镉、铟、锡、锑、碲、金、汞、铊、铅、铋、钍、铀共25种痕量元素的方法。在优化的实验条件下,校准曲线线性相关系数均在0.999以上,各元素的方法检出限在0.003～0.15 μg/L之间,定量限在0.010～0.50 μg/L之间。选择3个高纯镍样品(纯度为99.99%),按实验方法对其中25种痕量元素进行测定,同时对同一高纯镍样品进行不同梯度的加标回收试验,结果表明,测定结果的相对标准偏差(RSD,n=8)为3.5%~9.7%,回收率为90%～110%。采用实验方法测定纯镍标准物质,测定值与标准值基本一致。按照实验方法对高纯镍样品中25种杂质元素进行测定,同时采用辉光放电质谱法进行方法比对,结果表明,两种分析方法测定结果吻合度较高。     

航空伽玛能谱数据在突泉地区铀成矿预测中的应用

受森林分布广、覆盖厚及矿体隐伏等因素制约,大兴安岭成矿带突泉地区铀找矿进展缓慢。航空伽玛能谱数据蕴含有丰富的铀矿化信息,除地表矿化信息外,亦含有部分深部铀矿化弱信息。在典型铀矿点地质特征及伽玛能谱特征分析的基础上,利用K、U、Th元素含量之间的地球化学特征差异,构建了3个航放参数模型(U高场、△U高值晕、N高值晕),增强航放微弱异常信息。在航放异常信息提取、优选的基础上,结合地质、化探等找矿有利信息,预测铀成矿远景区9处。其中4处远景区成矿地质条件优越,异常线索丰富,尚属铀矿空白区,在进一步工作中应引起重视。     

Mechanism of CeO_2 synthesized by thermal decomposition of Ce-MOF and its performance of benzene catalytic combustion

In this paper,the formation mechanism of mesoporous CeO_2 synthesized by thermal decomposition of Ce-MOF and its performance of benzene catalytic combustion,as well as the structure-activity relationship between them were studied in depth.The self-assembly process and physicochemical properties of CeO_2 were characterized by thermogravimetry analysis,powder X-ray diffraction,N_2 adsorption/desorption,high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy techniques.Characterization results show that Ce-MOF is completely decomposed into pure mesoporous CeO_2 when the decomposition temperature is higher than 400℃.At this threshold temperature,CeO_2(400) has the largest specific surface area and pore volume of 114 m~2/g and 0.152 cm3/g,respectively.CeO_2(400) exhibits very high catalytic activity for benzene combustion,which can completely catalyze the degradation of benzene at 260℃.Meanwhile,the mesoporous CeO_2(400) supported Pt nanocrystalline catalysts were prepared by high temperature solution-phase reduction method.Pt/CeO_2(400)can completely degrade benzene at about 200℃ and represents high durability and good waterresistance for benzene combustion during 100 h of continuous reaction.     

高温燃烧红外吸收法快速测定铜精矿中的硫

研究采用高温燃烧红外吸收法测定钢精矿中高硫的方法。与经典的硫酸钡重量法及高温燃烧中和法相比,新方法 具有快速、准确、简便等优点。可测定铜精矿中10％～35％的高硫,相对标准偏差(RSD,n=8)小于1.0％。     

热喷涂技术的发展及应用

热喷涂技术是随着现代航空、航天技术的发展而发展起来的。已广泛应用于航空、航天、军事、纺织、机械、电力、化工、生物工程等各个领域，是一项具有广阔应用前景的技术。文中对火焰喷涂、电弧喷涂、等离子喷涂和特殊喷涂的主要内容及其技术特点进行了综述，并展望了热喷涂的应用及发展趋势。     

废弃印刷线路板Pb,Cd和Cr的测定

研究用原子吸收分光光度计测定废弃印刷线路板中重金属元素Pb，Cd和Cr的含量。结果表明，方法灵敏、快速、准确、操作方便，实用性强。Pb，Cd和Cr的回收率在98．9％～103．6％之间，相对标准偏差RSD〈1．45％。     

原子吸收法测定阳极泥及其浸出渣中银

试样经王水分解，在氨性介质中用原子吸收法直接测定阳极泥及其浸出渣中银。方法简便、快速、准确。回收率为９７％－１０５％，相对标准偏差优于±５％。     

Germanium-antimony-selenium-tellurium thin films: Clusters formation by laser ablation and comparison with clusters from mixtures of elements

Quaternary germanium-antimony-selenium-tellurium (Ge-Sb-Se-Te) thin films deposited from Ge_19.4Sb_16.7Se_63.9−xTe_x (x = 5, 10, 15, and 20) glass-ceramics targets by radio frequency magnetron sputtering were studied using laser ablation quadrupole ion trap time of flight mass spectrometry. Binary, ternary, and quaternary Ge_aSb_bSe_cTe_d clusters were formed and their stoichiometry was determined. By comparison of the clusters obtained from quaternary Ge-Sb-Se-Te thin films and those from ternary Ge-Sb-Te materials, we found that Ge-Te species are not detected from the quaternary system. Furthermore, Ge-Se and Se-Te species are missing in mass spectra generated from Ge-Sb-Se-Te thin films. From the Ge-Sb-Se-Te thin films, 16 clusters were detected while ternary Ge-Sb-Se glasses yielded 26 species. This might be considered as a signal of higher stability of Ge-Sb-Se-Te thin films which is increasing with a higher content of Te. The missing (Se₂⁺, Ge_aSb⁺ (a = 1–4), and GeSe_c⁺ (c = 1, 2)) and new (Ge⁺ and Sb_bTe⁺ (b = 1–3)) clusters may indicate that some of the structural features of the films (Ge₂Se_6/2 and Se₂Sb-SbSe₂) were replaced by (GeSe_4−xTe_x and SbSe_3−xTe_x) ones. In addition, when comparing the stoichiometry of clusters formed from Ge-Sb-Se-Te thin films with those from the mixtures of the elements, only Sb₃⁺ and SbSe⁺ were observed in both cases. The knowledge gained concerning clusters stoichiometry contributes to the elucidation of the processes proceeding during plasma formation used for the chalcogenide thin films deposition.