Nanoassembly Growth Model for Subdomain and Grain Boundary Formation in 1T′ Layered ReS2

Grain boundaries (GBs) significantly affect the electrical, optical, magnetic, and mechanical properties of 2D materials. An anisotropic 2D material like ReS₂ provides unprecedented opportunities to explore novel GB properties, since the reduced lattice symmetry offers greater degrees of freedom to build new GB structures. Here the atomic structure and formation mechanism of unusual multidomain and diverse GB structures in the vapor phase synthesized ReS₂ atomic layers are reported. Using high‐resolution electron microscopy, two major categories of GBs are observed in each ReS₂ domain, namely, the joint GB including three structures, and the GBs formed from a reconstruction of Re4‐chains including seven different structures. Based on the experimental observations, a novel “nanoassembly growth model” is proposed to elucidate the growth process of ReS₂, where three types of Re4‐chain reconstruction give rise to a multidomain structure. Moreover, it is shown that by controlling the thermodynamics of the growth process, the structure and density of GB in the ReS₂ domain can be tailored. First‐principles calculations point to interesting new properties resulting from such GBs, such as a new electron state or ferromagnetism, which are highly sought after in the construction of novel 2D devices.     

Photoactive Electro-Controlled Visual Perception Memory for Emulating Synaptic Metaplasticity and Hebbian Learning

In bionic technology, it has become an innovative process imitating the functionality and structuralism of human biological systems to exploit advanced artificial intelligent machines. Bionics plays a significant role in environmental protection, especially for its low energy loss. By fusing the concept of receptor-like sensing component and synapse-like memory, the photoactive electro-controlled optical sensory memory (PE-SM) is proposed and realized in a single device, which endows a simple methodology of reducing power consumption by photoactive electro-control. The PE-SM is the system built with the stacked atomically thick materials, in which rhenium diselenide serves as a robust photosensor, hexagonal boron nitride serves as a tunneling dielectric, and graphene serves as a charge-storage layer. With the features of the PE-SM, it performs synaptic metaplasticities under optical spikes. In addition, a simulated spiking neural network composed of 24 × 24 PE-SMs is further presented in an unsupervised machine learning environment, performing image recognition via the Hebbian rule. The PE-SM not only improves the neuromorphic computing efficiency but also simplifies the circuit-size structure. Eventually, the concept of photoactive electro-control can extend to other photosensitive 2D materials and provide a new approach of constructing either visual perception memory or photonic synaptic devices.     

The Effect of Water on the Activity and Selectivity for γ-Alumina Supported Cobalt Fischer–Tropsch Catalysts with Different Pore Sizes

The effect of water on the activity and selectivity for a series of γ-Al₂O₃ supported cobalt Fischer–Tropsch catalysts has been studied in an isothermal fixed-bed reactor at T = 483 K, P = 20 bar, and H₂/CO = 2.1. The catalysts were produced applying incipient wetness impregnation and consisted of 20 wt.% cobalt and 0.5 wt.% rhenium deposited on γ-Al₂O₃ supports with different pore characteristics. For the narrow-pore catalysts, addition of water corresponding to an inlet partial pressure ratio of P_H2O/P_H2 = 0.4 reduced the reaction rates. In contrast, for a catalyst with larger pores the same water pressure increased the reaction rates. For all catalysts, water amounts equal to P_H2O/P_H2 = 0.7 at the reactor inlet suppressed the reaction rates and led to permanent deactivation. The addition of water increased the C₅₊ selectivity and decreased the CH₄ selectivity for all catalysts. The pore characteristics seem to determine the effect of water on the rates.     

Metal separations of interest to the Chinese metallurgical industry

IBC Advanced Technologies’ Molecular Recognition Technology(MRT) SuperLig products selectively and rapidly bind with target species enabling their selective removal from solutions.The MRT process can produce a high purity separation product of maximum added value at a competitive cost.SuperLig products have high selectivity for many target species which can include metal ions,anions,and neutral molecules.In operation,the SuperLig product is first placed in a packed column.A solution containing a mixture of the target species and other chemical species is then passed through the column.The target species is removed selectively by the SuperLig product,the column is washed to remove residual feed solution,and the target species is recovered by a minimal quantity of eluent.The result is a pure and concentrated species that can be kept for its value or disposed of safely.The process is environmentally and ecologically friendly with no organic solvents being used.This paper provides a review of some examples of applications of MRT to separations of interest to the Chinese metallurgical industry.Included are several applications of MRT,including Pd separations from Pt metal refinery streams and low-grade spent catalyst wastes,Rh recovery from spent auto catalyst and other feeds,Re removal from selected impurity ions,Cd removal from Co electrolyte,Bi removal from Cu electrolyte,In and Ge separations from difficult matrices,and removal of bivalent first transition series and other metal ions from acid mine drainage(Berkeley Pit,Montana).Finally,the potential application of MRT to separations involving the recovery of rare earth metals and Li from low-level waste solutions and end-of-life products is discussed.     

铼的分离分析方法研究进展

介绍了萃取分离、离子交换、液膜分离、活性炭吸附等四种铼的主要分离富集方法,以及分光光度法、等离子体-质谱法等铼的分析方法,指出了不同方法的特点及使用范围,并展望了铼的分离分析方法的发展方向。     

电子束悬浮熔炼钼铼合金铸锭的热加工方法

电子束悬浮熔炼钼铼合金铸锭晶粒粗大,致使热加工性能变差,锻造过程出现开裂,文章分析了锻造过程材料的受力状态,认为是垂直晶界的拉应力导致沿晶开裂,据此提出了热轧开坯的工艺方法,且规定第1道次平行铸锭轴向喂料,轧制过程中材料产生剪切滑移变形,滑移面与晶界成一定夹角,不产生垂直晶界的拉应力,避免了拉应力作用下的沿晶开裂,获得优质热轧板。     

高铼酸的制备研究

以高铼酸铵为原料,分别采用50%TBP+50%260#溶剂油萃取法和C160树脂离子交换—真空旋转蒸发二步法制备高铼酸。结果表明,采用上述两种方法均可制得符合行业标准YS/T 836—2012要求的Ⅰ级高铼酸产品,其中萃取法铼回收率为97.47%,NH4+去除率高达99.993%;离子交换法铼损失率为0.035%,C160阳离子树脂对NH4+的穿透吸附容量为33.6g/L。     

钼精矿焙烧烟道灰中铼的回收

含铼钼精矿经外加热式回转窑焙烧,伴生的稀贵金属铼进入烟尘,采用自激式高效收尘方式和装置进行回收,对焙烧烟尘中的主要成分进行分析,研究了浸出过程的主要影响因素:浸出剂、酸度、温度、时间、液固比等,把回收的含铼钼粉尘进行溶解,通过添加氧化剂,提高铼的浸出率,将含铼溶液,选择强碱性阴离子交换树脂201×7吸附,再用萃取剂萃取,用7N的氨水反萃,铼进入反萃液中,再用氨水解吸、蒸发、结晶得高铼酸铵。该工艺有效的回收了烟尘中的铼,粉尘回收率可达到98%以上,减少粉尘排放,降低环境污染;烟尘中的铼的浸出率在98%以上;溶液中铼的吸附率在99%以上,附铼树脂上铼的解析率在99%以上;铼酸铵纯度≥99.99%,总回收率≥98%;提高了矿产资源综合利用率及经济效益,为企业增加了新的经济增长点。     

Selective Adsorption of Mo(VI) From Re(VII) Containing Effluent on Orange Waste Gel Modified by Ethylenediamine,Diethylamine, and Triethylamine

New adsorption gels were prepared by chemically immobilizing functional groups of ethylenediamine, diethylamine and/or triethylamine on orange waste, named OW-en, OW-DEA, and OW-TEA, respectively. By comparing with the adsorption of other coexisting metals, such as Re(VII), Pb(II), Fe(III), Zn(II), Mn(VII), Ca(II), and Cu(II), the novel gels exhibited selectivity only for Mo(VI) and the adsorption behavior obeys the Langmuir model. The maximum adsorption capacity for molybdenum was in the order, OW-en (2.17 mol/kg) > OW-TEA (1.26 mol/kg) > OW-DEA (0.88 mol/kg). A kinetic study for the adsorption of molybdenum at various temperatures confirmed that the endothermic adsorption process followed pseudo-second order kinetics. In addition, its excellent adsorption characteristics for Mo(VI) were confirmed by the adsorption and elution tests using a column packed with the OW-en gel, especially by separation of Mo(VI) from Mo-Re containing industrial effluent.     

Acidic Leaching with Chlorate as Oxidizing Agent to Extract Mo and Re from Molybdenite Flotation Concentrate in a Copper Plant

The technology of molybdenum extraction from molybdenite concentrate by using potassium chlorate (KClO₃) or sodium chlorate (NaClO₃) has been investigated. The results show that leaching time, leaching temperature, agitation speed, oxidizer type, potassium or sodium chlorate, and hydrochloric acid concentration have significant effect on the molybdenum extraction efficiency. Optimum process operating parameters were established as follows: 4 hrs, hydrochloric acid concentration: 35%, solids ratio: 5%, temperature: 65-70°C, agitation speed: 600 rpm, the mass of potassium chlorate and sodium chlorate: 25 g. Under these experimental conditions, the extraction of molybdenum and rhenium were obtained about 85% and 100%, respectively.