Fe XVII离子能级和振子强度的相对论多组态Dirac-Fock计算

本文用相对论多组态的狄拉克-福克(Dirac-Fock)(MCDF)近似方法计算了铁的类氖离子FeXVII的2p~53s,和3p和3d态的所有能级以及3s—3p,3p—3d跃迁的电偶极振子强度f值.理论计算的能级值同实验值的比较表明,使用MCDF方法计算类氖等电子序列的能级会得到与实验值符合得比较好的结果.因无实验数据可作比较,本文得到的振子强度值纯属理论预言值.     

An ion-imprinted amino-functionalized silica gel sorbent prepared by hydrothermal assisted surface imprinting technique for selective removal of cadmium (II) from aqueous solution

A new ion-imprinted amino-functionalized silica gel sorbent was synthesized by the hydrothermal-assisted surface imprinting technique using Cd²⁺ as the template, 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (AAAPTS) as the functional monomer, and epichlorohydrin as the cross-linking agent (IIP-AAAPTS/SiO₂) for the selective removal of Cd²⁺ from aqueous solution, and was characterized by FTIR, SEM, nitrogen adsorption and the static adsorption-desorption experiment method. The specific surface area of the IIP-AAAPTS/SiO₂ sorbents was found to be 149 m² g⁻¹. The results showed that the maximum static adsorption capacities of IIP-AAAPTS/SiO₂ sorbents by hydrothermal heating method and by the conventional heating method were 57.4 and 31.6 mg g⁻¹, respectively. The IIP-AAAPTS/SiO₂ sorbents offered a fast kinetics for the adsorption and desorption of Cd(II). The relative selectivity coefficients of IIP-AAAPTS/SiO₂ sorbents for Cd²⁺/Co²⁺, Cd²⁺/Ni²⁺, Cd²⁺/Zn²⁺, Cd²⁺/Pb²⁺ and Cd²⁺/Cu²⁺ were 30.68, 14.02, 3.00, 3.12 and 6.17, respectively. IIP-AAAPTS/SiO₂ sorbents had a substantial binding capacity in the range of pH 4-8 and could be used repeatedly. Equilibrium data fitted perfectly with Langmuir isotherm model compared to Freundlich isotherm model. Kinetic studies indicated that adsorption followed a pseudo-second-order model. Negative values of ΔG° indicated spontaneous adsorption and the degree of spontaneity of the reaction increased with increasing temperature. ΔH° of 26.13 kJ mol⁻¹ due to the adsorption of Cd²⁺ on the IIP-AAAPTS/SiO₂ sorbents indicated that the adsorption was endothermic in the experimental temperature range.     

Radiation damage and annealing in Sb implanted diamond

The predicted, but as yet unobserved, intradonor absorption spectrum of the hydrogenic-like donors in CdF₂ crystals is presented. The role of phonon coupling in these spectra is discussed. From the data on the insulator-semiconductor transition in CdPbF₂ it is concluded that the dominant factor in convertibility of CdF₂ to a semiconducting state is its electron affinity, the largest among the fluorites (x≈4 eV).     

流动注射在线离子交换柱富集-火焰原子吸收光谱法测定钨矿中的铜、锌和铅

建立了流动注射在线离子交换柱富集-火焰原子吸收光谱法测定钨矿中的铜、锌和铅的方法,样品经盐酸和硝酸分解后,加入5%宁可辛溶液使样品中大量的钨呈钨酸析出,样品中一般的伴生元素都可形成可溶性化合物与钨酸分离,之后采用流动注射在线富集与原子吸收联用技术,分别加入浓度依次递增的3种元素的标准溶液,用空气-乙炔火焰原子吸收连续测定Cu、Zn和Pb的含量。建立了优化的仪器工作条件,并对可能存在的元素进行干扰试验。方法检出限Cu为0.001μg/mL、Zn为0.001μg/mL、Pb为0.01μg/mL,相对标准偏差Cu为2.7%、Zn为3.6%、Pb为1.9%,加标回收率为96%—106%。     

Expiratory Muscle Training Increases Pressure Support in High School Band Students

An experiment to increase expiratory muscle strength for instrumentalists, using a high-intensity, low-repetition expiratory training method, was conducted with 40 healthy high school band players. Subjects trained five days per week for 2 weeks using four sets of six training breaths for a total of 24 training breaths with a spring-loaded pressure relief valve that provided an adjustable threshold. The training valve pressure was set at 75% of the subject's measured maximum expiratory pressure (up to 80 cm H₂O). Results demonstrated that high-intensity, low-repetition expiratory exercises significantly increased expiratory pressure generating capacity in these subjects and the degree of the training effect was similar regardless of the instrument the band member played. The training effect occurred within 2 weeks of initiating expiratory muscle training. Thus, this simple method of expiratory-specific strength training is effective and efficient for increasing expiratory pressure support in high school band students and has possibilities of a respiratory support device for many high pressure generating purposes. The potential mechanisms of the training effect are discussed.     

(Im-)possible ISOL beams

Refractory elements, i.e. elements with very high melting point and low vapor pressure, cannot be released in atomic form from an ISOL target. Therefore most of these elements are presently not available as ISOL beams. However, when reactive gases are introduced into the target, they may form volatile compounds with the refractory elements, allowing for an easier transport to the ion source. Particularly useful are high-temperature stable fluorides and oxides. By these chemical evaporation methods so far ISOL beams of the refractory elements C, Zr, Hf and Ta have been produced. We discuss how ISOL beams of B, Ti, Nb, Mo, Tc, Ru, W, Re, Os and Ir could be produced in a similar way.     

Fragmentation of elongated-shaped ZnO nanostructures into spherical particles by swift ion impact

This work reports on the fragmentation of rod-shaped ZnO nanostructures into spherical nanoparticles under 120 MeV Ag⁹⁺ swift ion irradiation. The visual evidence of the irradiation induced morphological change has been witnessed through electron microscopic studies. Typically, rods of 50 nm length and 21 nm diameter have transformed into particles of smaller dimension. Conversely, X-ray diffraction studies have revealed the lowering of crystallite size from 21.5 nm to 9 nm and an increase in microstrain by 11 times. Further, spectroscopic results, such as, significant blue shift (∼24 cm⁻¹) in vibrational features of Zn–O bonding, increase in native defect concentration in the nanostructures etc. also favor the irradiation led modification of nanostructures. It was anticipated that, dislodging and recrystallization of the constituent atoms of the elongated systems, as a consequence of suppression of the cohesive energy (owing to enormous energy deposition) caused by energetic ion irradiation, is chiefly responsible for the evolution of spherical nanoparticles.     

用水物理模型表征纯水离子积

纯水被描述为离解成水合氢离子(H₃O)¹⁺和氢氧根离子(HO)^1-, 平衡常数在液态水的温度和压力范围内被称为离子积,即两种离子的平衡态浓度的乘积. 用非线性最小二乘法把实验数据拟合成基于化学热力学的平衡态方程. 本工作提出一个全新的、基于统计物理的水离子积方程,其中的离子为带正电的质子和带负电的质子空穴(质穴). 把0-100 ℃纯水的实验数据用非线性最小二乘法拟合的方程,给出的结果比35年工业标准更准确.     

超高强块体非晶合金的研究进展

研制具有极限力学性能的金属材料一直是材料研究人员的梦想.超高强块体非晶合金是一类具有极高断裂强度(4 GPa)、高热稳定性(玻璃化转变温度通常高于800 K)和高硬度(通常高于12 GPa)的新型先进金属材料,其代表合金材料Co-Ta-B的断裂强度可达6 GPa,为目前公开报道的块体金属材料的强度记录值.本文系统地综述了该类超高强度块体非晶合金的组分、热学性能、弹性模量及力学性能,阐述了该类材料的研发历程;以弹性模量为联系桥梁,阐明了该类超高强块体非晶合金材料各物理性能的关联性,并揭示了其高强度、高硬度的价键本质.相关内容对于材料工作者了解该类超高强度金属材料的性能和特点,并推进该类材料在航空航天先进制造、超持久部件、机械加工等领域的实际应用有着重要意义.