Studies on the Construction Parameter of an Artificial Occluded Cell for In-situ Inspection of the Propagation Rate of Localized Corrosion

An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state (i.e., non-passive state) have been studied. The results showed that the developed electrochemical system can satisfactorily imitate a naturally formed localized corrosion and the coupling current can indicate the maximum localized propagating rate. In this artificial system, the anodic dissolution reaction followed the auto-catalytic mechanism. The localized corrosion current density was dependent on the area ratio R of the cathode to the occluded anode. While R was equal to or more than 6, the coupling current reached at a maximum value and did not alter with the increase in R-value. Therefore, R=7 is chosen as one of these optimum parameters used in constructing the system, with which the biggest galvanic current might be obtained. In contrast, the thickness of the polymer filler separating the occluded anode area from the bulk electrolyte solution and the volume of the occluded anode area did not affect the corrosion current obviously. They might affect the response time to approach a steady state.

An approach of constructing mixed-level orthogonal arrays of strength≥3

Orthogonal arrays (OAs), mixed level or fixed level (asymmetric or symmetric), are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurations. In this paper, we establish a general "expansive replacement method" for constructing mixedlevel OAs of an arbitrary strength. As a consequence, a positive answer to the question about orthogonal arrays posed by Hedayat, Sloane and Stufken is given. Some series of mixed level OAs of strength ≥3 are produced.

In-situ formed NiS/Ni coupled interface for efficient oxygen evolution and hydrogen evolution

High-performance electrocatalysts for water splitting are desired due to the urgent requirement of clean and sustainable hydrogen production.To reduce the energy barrier,herein,we adopt a facile in-situ surface modification strategy to develop a low-cost and efficient electrocatalyst for water splitting.The synthesized mulberry-like NiS/Ni nanoparticles exhibit excellent catalytic performance for water splitting.Small overpotentials of 301 and 161 mV are needed to drive the current density of 10 mA cm^-2 accompanying with remarkably low Tafel slopes of 46 and 74 mV dec^-1 for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER),respectively.Meanwhile,a robust electrochemical stability is demonstrated.Further high-resolution X-ray photoelectron spectroscopy analyses reveal that the intrinsic HER activity improvement is attributed to the electron-enriched S on the strongly coupled NiS and Ni interface,which simultaneously facilitates the important electron transfer,consistent with the electrochemical impedance results.The post characterizations demonstrate that surface reconstructed oxyhydroxide contributes to the OER activity and NiS/Ni is an OER precatalyst.This structure construction with in-situ formation of active interface provides an effective way to design efficient electrocatalysts for energy conversion.

A Class of Key Predistribution Schemes Based on Orthogonal Arrays

Pairwise key establishment is a fundamental security service in sensor networks; it enables sensor nodes to communicate securely with each other using cryptographic techniques. In order to ensure this security, many approaches have been proposed recently. One of them is to use key predistribution schemes （KPSs） by means of combinatorial designs. In this paper, we use the Bush＇s construction of orthogonal arrays to present a class of key predistribution schemes for distributed sensor networks. The secure connectivity and resilience of the resulting sensor network are analyzed. This KPS constructed in our paper has some better properties than those of the existing schemes.

Production of Fibres from Lunar Soil:Feasibility,Applicability and Future Perspectives

The construction of a lunar base is considered to be an important step towards deep-space exploration by humanity,and will rely on the utilisation of in situ lunar resources.In this paper,we discuss the current knowledge on the feasibility of converting lunar soil to high-performance fibres that can be used for the construction of a lunar base.This fibre would be combined with further portions of lunar soil to generate fibre-reinforced composites,which is utilized as multi-functional materials for lunar base construction.We discuss and analyse the latest findings regarding the composition of lunar soil simulants and their fibrisation properties,and techniques for fibre spinning and system integration.Finally,we suggest how the achievements made so far could be applied to the construction of a lunar base.