Reaction environment self-modification on low-coordination Ni2+ octahedra atomic interface for superior electrocatalytic overall water splitting

Large scale synthesis of high-efficiency bifunctional electrocatalyst based on cost-effective and earth-abundant transition metal for overall water splitting in the alkaline environment is indispensable for renewable energy conversion. In this regard, meticulous design of active sites and probing their catalytic mechanism on both cathode and anode with different reaction environment at molecular-scale are vitally necessary. Herein, a coordination environment inheriting strategy is presented for designing low-coordination Ni²⁺ octahedra (L-Ni-8) atomic interface at a high concentration (4.6 at.%). Advanced spectroscopic techniques and theoretical calculations reveal that the self-matching electron delocalization and localization state at L-Ni-8 atomic interface enable an ideal reaction environment at both cathode and anode. To improve the efficiency of using the self-modification reaction environment at L-Ni-8, all of the structural features, including high atom economy, mass transfer, and electron transfer, are integrated together from atomic-scale to macro-scale. At high current density of 500 mA/cm², the samples synthesized at gram-scale can deliver low hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) overpotentials of 262 and 348 mV, respectively.

     

Chemical bond characteristics and infrared reflectivity spectrum of a novel microwave dielectric ceramic CaIn2O4 with near-zero τf

Orthorhombic-structured CaIn₂O₄ ceramics with a space group Pca2₁ were synthesized via a solid-state reaction method. A high relative density (95.6 %) and excellent microwave dielectric properties (ε_r ～11.28, Qf = 74,200 GHz, τ_f ～ ?4.6 ppm/°C) were obtained when the ceramics were sintered at 1375 °C for 6 h. The dielectric properties were investigated on the basis of the Phillips–Van Vechten–Levine chemical bond theory. Results indicated that the dielectric properties were mainly determined by the InO bonds in the CaIn₂O₄ ceramics. These bonds contributed more (74.65 %) to the dielectric constant than the CaO bonds (25.35 %). Furthermore, the intrinsic dielectric properties of the CaIn₂O₄ ceramics were investigated via infrared reflectivity spectroscopy. The extrapolated microwave dielectric properties were ε_r ～10.12 and Qf = 112,200 GHz. Results indicated that ion polarization is the main contributor to the dielectric constant in microwave frequency ranges.     

Input-to-state learning of recurrent neural networks with delay and disturbance

This article deals with the issue of input-to-state stabilization for recurrent neural networks with delay and external disturbance. The goal is to design a suitable weight-learning law to make the considered network input-to-state stable with a predefined -gain. Based on the solution of linear matrix inequalities, two schemes for the desired learning law are presented via using decay-rate-dependent and decay-rate-independent Lyapunov functionals, respectively. It is shown that, in the absence of external disturbance, the proposed learning law also guarantees the exponential stability of the network. To illustrate the applicability of the present weight-learning law, two numerical examples with simulations are given.     

Overview of Physical and Chemical,Operational Properties of Nitrous Oxide Used as a Propellant for Low-thrust Rocket Engines

The results of a system analysis of the efficiency of nitrous oxide(N_2O) as a propellant component for small space vehicles(SSV) were presented. A criterion for mass efficiency of the SSV propulsion system(PS) is determined. The current global state-of-the-art of SSV PSs is shown. The application field of nitrous oxide in SSV PSs is calculated and mass efficiency of N_2O application is quantitatively determined. An overview of physical and chemical as well as operational properties of nitrous oxide as a promising, non-toxic component of rocket propellant is provided. Main physical and chemical constants of gaseous and liquid nitrous oxide; chemical properties of N_2O, thermal stability of N_2O, catalytic decomposition of N_2O, a mechanism of decomposition of N_2O, catalysts for decomposition of N_2O, ballast additives to N_2O, application of nitrous oxide, nitrous oxide as a rocket propellant, production of nitrous oxide, toxicity of nitrous oxide, fire hazard of N_2O, requirements to equipment when handling N_2O; storage and transportation of N_2O are considered. It is demonstrated that nitrous oxide is a chemical compound meeting the requirements to rocket propellants, including those related to the environmental friendliness of propellants. With 75 references.     

Anchoring DTPA grafted PEI onto carboxylated graphene oxide to effectively remove both heavy metal ions and dyes from wastewater with robust stability

Highly efficient adsorbents, which can effectively remove both metal ions and dyes from wastewater with robust stability, are strongly required for the remediation of current polluted aqueous system, but still a challenge to be realized. Herein, a new adsorbent has been designed to solve this problem by anchoring diethylene triamine pentaacetic acid (DTPA) grafted polyethyleneimine (PEI) onto carboxylated GO (GOC-g-PD). Given the amino and carboxyl active groups from PEI and GOC/DTPA, our GOC-g-PD displays good adsorption capacity against not only inorganic metal ions (Cu²⁺ and Pb²⁺) but also organic dye (methylene blue: MB). The maximum adsorption capacity of GOC-g-PD for Cu²⁺, Pb²⁺ and MB reached 309.60 mg·g^?1, 316.17 mg·g^?1 and 262.10 mg·g^?1, respectively. Furthermore, our GOC-g-PD also exhibits good cycling stability and chemical stability against wide pH values. These outstanding properties revealed our GOC-g-PD held great potential in purifying the sewage discharged from industries.

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Formation of new functional materials and device heterostructures on the basis of nanosystems of superionic conductors

Search for conditions of conservation of fast ionic transport (FIT) in nanosystems of advanced superionic conductors (ASIC)[1-4] and synthesis of new types of device thin-film heterostructures on this basis is a fundamental scientific problem. ASICs (α-AgI, solid electrolytes of the family RbAg4I5, etc. ) are crystals with a record high level of ionic conductivity and a low value of activation energy E～0. 1 eV.     

应用泡沫浮选萃取法从排放水中回收钼

根据实验室的试验结果，推荐应用浮选萃取联合工艺从水溶液中回收Mo(Ⅵ）。这一工艺包括制取以钼酸铵形式的商品，和对所有的有机试剂作再生处理。萃取Mo(Ⅵ）的准备系统，应包括在反萃取胺和用NaOH使水溶液碱化到pH=12以后，通过添加水溶液以使煤油、壬醇和AHII捕收剂按规定的比例进行混合等作业。对在萃取器中获得的混合液进行相分离后，有机溶液可用作泡沫浮选萃取Mo(Ⅵ）的萃取剂，而水溶液则加入到原始溶液中。     

对依兰煤田钻孔缩径挤夹钻具事故的认识

针对依兰煤田钻探施工中出现的钻孔缩径挤夹钻具事故,提出产生事故的根本原因不是因岩层本身膨胀所致,而是由于某种岩层裂隙发育,渗透性良好,吸水性强,使钻孔孔壁泥皮迅速增厚所致,并提出预防事故的具体措施。     

Zu Fragen der Ausbildung und Weiterbildung im österreichischen Bergbau

Training and continuous education is today for the management of a mineral producing operation more important than ever before. The focus of education today in the field of mineral producing industry has not only to be dedicated versus the needs of the industry but also versus the importance of the ever increasing need of societal acceptance of industrial operations. Therefore it is expected that graduates from mining schools not only have a good knowledge of technical and economical subjects but also a good background for the realisation of environmental and safety targets for the people at work and in the neighbourhood of an operation. A strong request to the education and training at university level is therefore not only to deliver a broad knowledge but also the formation of a basis which allows to obtain authority for functions as “safety expert”, “Mine rescuer”, “waste disposal expert” and others. In the text the contents of the BSc study program “Natural resources” are reviewed and the training and education for a “Natural Resources Manager” together with the required continuous education is discussed.