Misfit Layer Compounds: A Platform for Heavily Doped 2D Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity, and topological properties. Their physical properties can be controlled by doping in electric double-layer field-effect transistors (FET). However, for the case of single layer NbSe₂, FET doping is limited to ≈ 1 × 10¹⁴ cm⁻², while a somewhat larger charge injection can be obtained via deposition of K atoms. Here, by performing angle-resolved photoemission spectroscopy, scanning tunneling microscopy, quasiparticle interference measurements, and first-principles calculations it is shown that a misfit compound formed by sandwiching NbSe₂ and LaSe layers behaves as a NbSe₂ single layer with a rigid doping of 0.55–0.6 electrons per Nb atom or ≈ 6 × 10¹⁴ cm⁻². Due to this huge doping, the 3 × 3 charge density wave is replaced by a 2 × 2 order with very short coherence length. As a tremendous number of different misfit compounds can be obtained by sandwiching TMDs layers with rock salt or other layers, this work paves the way to the exploration of heavily doped 2D TMDs over an unprecedented wide range of doping.     

CO2 Hydrogenation to Methanol Over Cu/ZnO/Al2O3 Catalyst: Kinetic Modeling Based on Either Single- or Dual-Active Site Mechanism

CO₂ hydrogenation to CH₃OH via heterogeneous catalysis is one of the most promising and available approaches for mitigation of anthropogenic CO₂ issues. In this work, thermodynamic equilibria of CO₂ to methanol were compared with experimental results at given conditions using a commercial Cu/ZnO/Al₂O₃ catalyst for CO hydrogenation to methanol. It was found that, the high pressure, low temperature, and high H₂/CO₂ ratio are favorable to methanol synthesis from CO₂. Furthermore, the kinetic data were measured with an isothermal integral reactor under temperature between 160 and 240 °C, lower than that for CO hydrogenation to methanol reaction. Based on the single-active site and dual-active site LH mechanisms, both kinetic models can achieve full illustration of the influence of the operating conditions and the mechanisms. According to comparative analysis of the error variances of model correlations and the adsorbate coverages on the active sites, the dual-site mechanism identified to be superior to the single-site one for methanol synthesis from CO₂ feedstock. Overall, this paper provides fundamental understanding of the thermodynamic and kinetic aspects of a central route for CO₂ Valorisation.

Graphical Abstract

     

Physicochemical characteristics of a southern Lake Michigan river plume

Riverine inputs are a major source of nutrients to the Laurentian Great Lakes and have important effects on nearshore biological processes, where mixing between river and lake water leads to formation of heterogeneous river plumes. We examined the physical and chemical characteristics of the St. Joseph River plume in southern Lake Michigan between May and October 2011, and in October 2012, June 2013 and April 2014. Specific electric conductivity and stable isotopes of water were used to quantify the fraction of river water (FRW) at sampling sites in Lake Michigan. Both tracers predicted similar patterns of FRW among sites; however, there was a systematic offset between the two methods, and specific electric conductivity method under-predicted the FRW by ~5%. We observed a distinct, seasonally varying river plume, with plume size correlated with flow rate of St. Joseph River. Within the plume, sediments and nutrients were non-conservative and exhibited significant and seasonally varying losses that we attribute to settling of particle-bound nutrients and/or nutrients in particulate phase below the plume. The characteristics and the spatiotemporal heterogeneity of the river plume documented here may have important implications for the nearshore biogeochemistry of the Great Lakes and for understanding the roles of these features in ecological processes in nearshore areas.     

The integration of ergonomics into design—A review

This paper examines the role of ergonomics in product and systems design. Market requirements as well as legislation have increased the use of ergonomics in design. This has increased the demands upon both ergonomists and designers. The ergonomist must learn to participate in the product development team. In return the design team must find the time and resources necessary for the inclusion of ergonomics in the development programme. This paper discusses the different roles played by the ergonomist in each stage of product and systems design. The need to give designers, engineers and management a fundamental education in ergonomics is highlighted as is the need for the ergonomist to consider the financial consequences of his work.     

Developing strategies for robust energy systems. II: Application to CO2 risk management

One of the most important determinants for the design of the future energy system is whether or not constraints on CO₂ emissions will be imposed. Here, this issue is treated as a decision under uncertainty. Three strategies have been considered: immediate action to adapt to a future emission constraint (Commitment), business as usual (No Hedging), and hedging (Hedging). In the case of hedging, preparations are made outside the energy system, but the energy system itself is allowed to develop according to baseline assumptions until the uncertainty has been resolved. The IEA-MARKAL model has been used to show how efficient and robust the three strategies are under different developments. The development of the Swedish energy system has been studied for two rates of economic growth in combination with three nuclear policies and two CO₂ policies. The value of preparations for meeting a possible restriction on CO₂ emissions, i.e., following either the Commitment or the Hedging strategy, is considerably higher when the energy demand increases rapidly. In the low growth case, the choice of strategy is largely dependent upon the decision maker's estimate of the likelihood of an emission cap. In the high growth case, this likelihood must be considered to be very small in order to choose the No Hedging strategy, even with reinvestments in nuclear capacity beyond 2010.     

A synthetic IgG-binding domain based on staphylococcal protein A

A synthetic IgG-binding domain based on staphylococcal proteinA was designed with the aid of sequence comparisons and computergraphic analysis. A strategy, utilizing non-palindromic restrictionsites, was used to overcome the difficulties of introducingshe-specific changes into the repetitive gene. A single mutagenizedgene fragment was polymerized to different multiplicities, andthe different gene products were expressed in Escherichia coli.Using this scheme, protein A-like proteins composed of differentnumbers of IgG-binding domains were produced. These domainswere changed to lack asparagine-glycine dipeptide sequencesas well as methionine residues and are thus, in contrast tonative protein A, resistant to treatment with hydroxylamineand cyanogen bromide.     

Empirical evaluation of the reformed assembly work at the Volvo Uddevalla plant: Psychosocial effects and performance aspects

This paper reports on the innovative, now defunct, Volvo Uddevalla final assembly plant. Theoretical frames of reference, the design process and empirical data on work group characteristics and working conditions are focused upon.

Information regarding the Uddevalla plant has been gathered during a long-term co-operation project with the Volvo Corporation. During the closing-down period we obtained full access to all the production engineering data and personnel files available. We also had the opportunity of studying the responses to a questionnaire distributed to a random sample of blue-collar workers.

Working conditions in Uddevalla in the form of psychosocial job factors are compared with industrial blue-collar workers in general as well as with assembly workers in the closed down Volvo Kalmar final assembly plant, which had a different, more traditional, production system. The paper also compares the psychosocial job factors, performance measures and work-group characteristics in the five assembly workshops in the Uddevalla plant.

In comparing assembly workshops, the paper contrasts two approaches to competence development and work structuring used in Uddevalla, namely (1) giving priority to individual in-depth training of a specific task or (2) giving priority to a large competence overlap between individuals in a work group.

Relevance to industry

This paper reports and explains some results from a multidisciplinary evaluation of shop-floor work in the Volvo Uddevalla plant, a full-scale assembly plant with parallellized flow and long cycle time, using autonomous work groups. These experiences should be of general interest to industries searching for the factory of the future.     

Intellectual competence and the intelligent personality: A third way in differential psychology.

This article conceptualizes the construct of the intelligent personality as an indicator of intellectual competence in an attempt to expand the traditional concept of intelligence and account for both ability and nonability determinants of academic performance. Theoretical implications are discussed with regard to recent attempts to (a) explain correlations between personality and intelligence measures, (b) conceptualize novel constructs that may bridge the gap between intelligence and personality, and (c) develop a conceptual model for understanding the relationship among individual differences underlying human performance in real-world settings. Practical implications are also considered, in particular with regard to the validity of the intelligent personality as a predictor of future achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

NMDA receptor complex blockade by oral administration of magnesium: comparison with MK-801

The ion channel of the N-methyl-D-aspartate (NMDA) receptor complex is subject to a voltage-dependent regulation by Mg2+ cations. Under physiological conditions, this channel is supposed to be blocked by a high concentration of magnesium in extracellular fluids. A single dose of magnesium organic salts (i.e., aspartate, pyroglutamate, and lactate) given orally to normal mice rapidly increases the plasma Mg2+ level and reveals a significant dose-dependent antagonist effect of magnesium on the latency of NMDA-induced convulsions; this effect is similar to that seen after administration of the dizocilpine (MK-801) channel blocker. An anticonvulsant effect of Mg2+ treatment is also observed with strychnine-induced convulsions but not with bicuculline-, picrotoxin-, or pentylenetetrazol-induced convulsions. In the forced swimming test, Mg2+ salts reduce the immobility time in a way similar to imipramine and thus resemble the antidepressant-like activity of MK-801. This activity is masked at high doses of magnesium by a myorelaxant effect that is comparable to MK-801-induced ataxia. Potentiation of yohimbine fatal toxicity is another test commonly used to evaluate putative antidepressant drugs. Administration of Mg2+ salts, like administration of imipramine strongly potentiates yohimbine lethality in contrast to MK-801, which is only poorly active in this test. Neither Mg2+ nor MK-801 treatment can prevent reserpine-induced hypothermia. These data demonstrate that oral administration of magnesium to normal animals can antagonize NMDA-mediated responses and lead to antidepressant-like effects that are comparable to those of MK-801. This important regulatory role of Mg2+ in the central nervous system needs further investigation to evaluate the potential therapeutic advantages of magnesium supplementation in psychiatric disorders.