人造岩石固wx 包容锕系核素废物

研究了富钙钛锆石型和富烧绿石型两种人造岩石固化体包容锕系核素的配方设计和固化产品的鉴定评价,包括物理性能、抗浸出性能和耐辐照性能。采用了X射线衍射(XRD)、扫描电镜/能谱分析(SEM/EDS)和透射电镜/能谱分析(TEM/EDS)研究了矿相组合、元素分布和矿相化学组成等。研究表明,富钙钛锆石和富烧绿石型人造岩石都能很好地固化包容锕系核素废物。     

CXN天然沸石的研究Ⅲ.新型 LiCl/H-STI主/客体固电解质的制 备与表征

利用自发热扩散法,将易潮解流失的LiCl(客体)固全到CXN沸石改所得的H－STI沸石(主体)上,形成新型主/客体材料,粉未XRD,SEM,FT-IR和TG/STA等方法表征显示LiCl已经分散到H－STI孔道中,实现了客体的稳定化,其分散阈值0.14g/g。负载量为阈值的样品在绝湿条件下的电导率比主体H－STI提高了四个数量级,是一种良好的固体电解质。     

CXN天然沸石的研究Ⅲ.新型 LiCl/H-STI主/客体固电解质的制 备与表征

利用自发热扩散法,将易潮解流失的LiCl(客体)固全到CXN沸石改所得的H－STI沸石(主体)上,形成新型主/客体材料,粉未XRD,SEM,FT-IR和TG/STA等方法表征显示LiCl已经分散到H－STI孔道中,实现了客体的稳定化,其分散阈值0.14g/g。负载量为阈值的样品在绝湿条件下的电导率比主体H－STI提高了四个数量级,是一种良好的固体电解质。     

杂原子Ti-ZSM-12分子筛的合成与结构表征

以甲基三乙基溴化铵为模板剂,水热晶化法合成出杂原子Ti-ZSM-12型分子筛.X射线衍射,扫描电镜,IR及XPS等现代技术手段研究表明杂原子Ti取代骨架Si原子而存在于ZSM-12分子筛骨架上.     

杂原子对Y沸石液固相类质同晶取代规律探讨

用NH~4BF~4,(NH~4)~3ZrF~7,(NH~4)~2Tif~6,(NH~4)~3FeF~6和CrF~3,3NH~4F等溶液为取代剂,对Y沸石实行液固相类质同晶取代,除了B以外, 其它金属元素均能代入沸石骨架,它们的取代程度为Fe>Ti>Cr≈Zr.采用XRD,IR和DTA 等手段对取代产物进行表征,证实杂原子已成为骨架元素.由液固相类质同晶取代机理出发, 对影响杂原子取代程度的主要因素进行了探讨,提出由杂原子的离子半径.含氟配合物累积稳定常数. 阳离子水解平衡常数和水解产物聚合平衡常数可以预测各种杂原子的取代效果.     

Tannery waste solidification and stabilization

The stabilization/solidification of tannery waste containing chromium was studied as an option for its treatment and final disposal, by using a Portland cement type II and two different commercial bentonites (sodium and organophilic) as additives. Different compositions were evaluated by compressive strength analysis, porosity measurement, leaching tests and thermal analysis. The effect on the compressive strength is directly related to the resulting effect of the components present in the original paste on the hydration degree of the cement, which can be evaluated by thermogravimetric analysis from the dehydration steps of tobermorite and ettringite phases of the pastes. The results show that this process is suitable for the treatment of the tanning waste and that the best conditions of stabilization are obtained when both additives are used. This revised version was published online in August 2006 with corrections to the Cover Date.     

Biosorption of actinides from dilute waste actinide solution by egg-shell membrane

Removal of radioactive elements from the effluent and waste aqueous solutions is an important problem. In previous laboratory batch experiments, hen egg-shell membrane (ESM) was stable as an insoluble protein and was very capable of binding heavy metal ions from aqueous solution. Batch laboratory pH profile, time dependency, and capacity experiments were performed to determine the binding of uranium (U) and thorium (Th) to ESM. Batch pH profile experiments indicated that the optimum pH for binding these actinides was approx 6.0 (U) or 3.0 (Th). The adsorption isotherms were developed at pH 5.0 (U) or 3.0 (Th) at 25°C, and the adsorption equilibrium data fitted both Langmuir and Freundlich models. The maximum uptakes by the Langmuir model were about 240 mg U/g and 60 mg Th/g dry weight ESM. In addition, their adsorption capacities increased as salt concentration increased. ESM could also accumulate uranium from dilute aqueous solution by adjusting to the optimum pH. These results showed that ESM was effective for removing actinides from solution and would be useful in filtration technology to remove actinides from aqueous solution. S.-I. Ishikawa is a research fellow at the Japan Society for the Promotion of Science.     

Th@C76. Computational characterization of larger actinide endohedral fullerenes

The actinide endohedral fullerene Th@C₇₆ was successfully prepared in a very recent experiment (Wang et al., J. Am. Chem. Soc. 2017 , 139, 5110) yet without any structural information. In this work, density functional theory calculations revealed that this novel molecule bears a T_d(19151)‐C₇₆ cage obeying the isolated pentagon rule. The internal Th atom is off‐centered and resides under a sumanene‐type hexagonal ring, formally donating 4e to the carbon cage. The metal position was rationalized by the structure and charge distribution of the negatively charged cage. Interestingly, an octahedron‐like dynamic trajectory of metal inside the C₇₆ cage at high temperature was found based on the cage symmetry and located transition state structures. Furthermore, the infrared, NMR, and UV/vis spectra of Th@C₇₆ were simulated to assist future experimental characterization.     

Periodic trends and complexation chemistry of tetravalent actinide ions with a potential actinide decorporation agent 5-LIO(Me-3,2-HOPO): A relativistic density functional theory exploration

A relativistic density functional theory (DFT) study is reported which aims to understand the complexation chemistry of An⁴⁺ ions (An = Th, U, Np, and Pu) with a potential decorporation agent, 5-LIO(Me-3,2-HOPO). The calculations show that the periodic change of the metal binding free energy has an excellent correlation with the ionic radii and such change of ionic radii also leads to the structural modulation of actinide–ligand complexes. The calculated structural and binding parameters agree well with the available experimental data. Atomic charges derived from quantum theory of atoms in molecules (QTAIM) and natural bond order (NBO) analysis shows the major role of ligand-to-metal charge transfer in the stability of the complexes. Energy decomposition analysis, QTAIM, and electron localization function (ELF) predict that the actinide–ligand bond is dominantly ionic, but the contribution of orbital interaction is considerable and increases from Th⁴⁺ to Pu⁴⁺. A decomposition of orbital contributions applying the extended transition state-natural orbital chemical valence method points out the significant π-donation from the oxygen donor centers to the electron-poor actinide ion. Molecular orbital analysis suggests an increasing trend of orbital mixing in the context of 5f orbital participation across the tetravalent An series (Th-Pu). However, the corresponding overlap integral is found to be smaller than in the case of 6d orbital participation. An analysis of the results from the aforementioned electronic structure methods indicates that such orbital participation possibly arises due to the energy matching of ligand and metal orbitals and carries the signature of near-degeneracy driven covalency.     

Comparative studies of quasi-relativistic density functional methods for the description of lanthanide and actinide complexes

We present a comparative Density Functional Theory (DFT) study based on two different implementations of relativistic effects within the Kohn-Sham (KS) approach, to describe the metal-ligand interaction in I(3)M-L complexes (L = NH(3), NCCH(3), CO and M = La, Nd, U). In the first model, the scalar corrections were included by a quasi-relativistic approach (QR) via the so-called ZORA or Pauli Hamiltonians, while in the second, these effects are taken into account in a quasi-Relativistic Effective Core Potential (RECP). These relativistic approaches were used in conjunction with various gradient corrected (GGA) or hybrid (SCH) functionals. The structural parameters obtained from geometry optimizations have been compared to experimental structural trends, and rationalized by a KS orbital analysis. Both approaches provide similar results for mainly ionic metal-ligand bonds (e.g., for the sigma-donor ligand L = NH(3)). For the pi-acceptor ligands (NCCH(3), CO), the QR approach is in agreement with experimental trends and consistent with the presence of a backbonding interaction between U(III) and the neutral ligand, which does not exist in the lanthanide homologues. The GGA/RECP methods also reproduce this phenomenon, while the SCH/RECP scheme fails to describe this interaction. The role of the RECP, of its size, and of additional polarization functions has also been examined. Finally, the failure of the SCH/RECP approach was interpreted as a consequence of a bad estimation of frontier orbital energy levels in the uranium and ligand species.     

The solidification behavior of a PBT/PET blend over a wide range of cooling rate

In recent years, much attention has been paid to the development of high‐performance polyester blends, among which blends of polybutylene terephthalate/polyethylene terephthalate (PBT/PET) are expected to exhibit remarkable properties as far as their crystallization behavior is concerned. Through trial and error, appropriate commercial compositions have been chosen which could not be otherwise explained by a suitable interpretation of the mechanisms determining their solidification behavior. The solidification behavior of a 60/40 w/w PBT/PET blend was studied in a wide range of cooling conditions, according to a continuous cooling transformation (CCT) procedure developed previously, aiming at emulating the typical conditions encountered in polymer processing. Several samples characterized by a homogeneous structure were solidified from the melt at various cooling rates and the resulting structure and properties were subsequently evaluated by analyzing the density, microhardness (MH), and wide angle x‐ray diffraction (WAXD). The resulting solidification behavior was then compared to that exhibited by the individual constituents of the blend (i.e., PBT and PET). The blend displayed a unique solidification behavior, conversely to those of the pure components which showed characteristics not recognized in the blend except at certain restricted cooling rates ranges. The cooling rate dependence observed in the blend does not bring similarities to the crystallization behavior of individual constituents since the fall down of density with cooling rate should be related to the rate controlling demixing stage of the two moieties just before crystallization occurs. The kinetics observed is thus a measure of the kinetics of demixing. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 799–810, 2009     

电感耦合等离子体发射光谱法测定二次电池废料中的钴含量

采用电感耦合等离子体发射光谱法(ICP-AES)法测定二次电池废料中的钴含量。根据分析线的选择原则,采用干扰少、灵敏度相对低的波长为201.153nm谱线作为方法分析线。以稳定性为原则优化了仪器测试条件,探讨了酸度效应和共存元素的影响。该方法具有快速简便、良好的准确度和精密度,校准曲线的线性相关系数为0.9999,加标回收率为94.3%~104.6%,相对标准偏差(n=8)小于1%。该方法适用于二次电池废料含量小于10%的钴量的测定,适用于工业化生产的日常分析。     

Molten and solidification properties of copper nanoparticles

The melting and solidifying processes are carried out using molecular dynamics simulations. The influencing mechanism of the simulation size and the crystal configuration after solidification on the molten and the solidification properties is explored. The results demonstrate that the crystal structure of solidified copper nanoparticle is sensitive to the size of the copper nanocubes. Polycrystalline appears in the solidified copper nanoparticle for the relatively larger copper cubes; correspondingly, the grain boundaries give rise to the increase of the average atomic energy. Whereas for the relatively small copper cubes, the solidified copper nanoparticles mainly present monocrystalline structure. Moreover, the relationship between the internal pressure of the liquid copper droplets and the droplet diameter is studied to clarify the surface tension property at nanoscale. It is found that the internal pressure of the liquid copper droplets is logarithmically linearly dependent on the diameter of the copper droplets, implying that the surface tension of the liquid copper is not sensitive to the diameter of the liquid copper droplets. The present findings will be helpful to the preparation of the copper nanoparticle‐based thin ribbon. Copyright © 2016 John Wiley & Sons, Ltd.     

Applications of thermal analysis in quality control of solidification processes

Summary Thermal analysis is widely used to determine solidification characteristics of metals and alloys in various metallurgical processes. Computer-Aided Cooling Curve Analysis (CA-CCA) is the most popular thermal analysis technique because of its ease of use and low cost. This paper discusses the principles of CA-CCA and zero curve calculations. The methods for calculating key solidification characteristics of metals from cooling curves are presented, and their importance in the quality control of manufacturing processes are demonstrated. Examples are presented for cast iron, copper and aluminum alloys.     

Effect of rapid solidification on heat capacities of Al-Sr alloys

Heat capacities of both the ingot-like and melt-spun Al-Sr alloys have been measured through the temperature range 373 to 1060 K using differential scanning calorimetry. The experimental results show that rapid solidification has a slight effect on the temperature dependence of the heat capacities of the Al-Sr alloys. The heat capacities of the melt-spun Al-Sr alloys increase more slowly than those of the ingot-like alloys with increasing temperature from 373 to 900 K. Furthermore, the effect of rapid solidification on the heat capacities becomes more obvious with increasing Sr concentration in the Al-Sr alloys. The data of the heat capacities between 373 and 900 K have been fitted with the least square method and a linear dependence on temperature was assumed for that temperature range. This revised version was published online in July 2006 with corrections to the Cover Date.