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This paper addresses the problem of H∞ control for a class of uncertain stochastic systems with Markovian switching and time-varying delays. The system under consideration is subject to time-varying norm-bounded parameter uncertainties and an unknown nonlinear function in the state. An integral sliding surface corresponding to every mode is first constructed, and the given sliding mode controller concerning the transition rates of modes can deal with the effect of Markovian switching. The synthesized sliding mode control law ensures the reachability of the sliding surface for corresponding subsystems and the global stochastic stability of the sliding mode dynamics. A simulation example is presented to illustrate the proposed method

Density functional theory study of the structural and electronic properties of single and double acceptor dopants in MX2 monolayers

Density functional theory calculations are used to systematically investigate the structural and electronic properties of MX2 transition metal dichalcogenide monolayers with M = Cr, Mo, W and X = S, Se, Te that are doped with single (V, Nb, Ta) and double (Ti, Zr, Hf) acceptor dopants on the M site with local D3h symmetry in the dilute limit. Three impurity levels that arise from intervalley scattering are found above the valence band maxima (VBM): an orbitally doubly degenerate e′ level bound to the K/K′ VBM and a singly degenerate a1′ level bound to the Γ-point VBM. Replacing S with Se or Te lowers the Γ point VBM substantially with respect to the K/K′ VBM bringing the a1′ level down with it. The relative positions of the impurity levels that determine the different structural and electronic properties of the impurities in p-doped MX2 monolayers can thus be tuned by replacing S with Se or Te. Single acceptors introduce a magnetic moment of 1μB in all MX2 monolayers. Out-of-plane magnetic anisotropy energies as large as 10 meV/dopant atom are found thereby satisfying an essential condition for long-range ferromagnetic ordering in two dimensions. For double acceptors in MS2 monolayers, both holes occupy the high-lying a1′ level with opposite spins so there is no magnetic moment; in MSe2 and MTe2 monolayers the holes occupy the e′ level, a Jahn-Teller (JT) distortion wins the competition with exchange splitting resulting in the quenching of the magnetic moments. Even when the JT distortion is disallowed, magnetic double acceptors have a large in-plane magnetic anisotropy energy that is incompatible with long-range magnetic ordering in two dimensions. The magnetic moments of pairs of single acceptors exhibit long-range ferromagnetic coupling except for MS2 where the coupling is quenched for impurity pairs below a critical separation. For Se and Te compounds, the holes are accommodated in high-lying degenerate e′ levels, which form triplets for all separations. However, for X=Te, a JT distortion lifts the degeneracy of the e′ levels leading to a reduction of the exchange interaction between impurity pairs. Deep, intrinsic, vacancy, and antisite defects that localize the holes might stabilize the magnetization of p-doped MX2 monolayers. Our systematic study of the p-doped MX2 monolayers identifies 1H CrTe2 and MoSe2 as the most promising candidates for room-temperature ferromagnetism. We combine the exchange interaction estimated from the energy difference calculated for ferromagnetically and antiferromagnetically coupled pairs with Monte Carlo calculations to estimate the Curie temperatures TC for vanadium-doped CrTe2 and MoSe2 monolayers. Room-temperature values of TC are predicted for V dopant concentrations of 5% and 9%, respectively. In view of the instability of CrTe2 in the 1H form, we suggest that the CrxMo1-x(TeySe1-y)2 alloy system be studied. A single d electron or hole is uncorrelated. However, in the single-impurity limit, the residual self-interaction of this carrier in the local spin density approximation (LSDA) can be corrected by introducing a Hubbard U. Doing so leads to a large increase of the ordering temperatures calculated in the LSDA (reducing the doping concentration needed to achieve room-temperature ordering) but at the expense of introducing an indeterminate parameter U.</p

DEVELOPMENT AND VALIDATION OF AN INSTRUMENT TO MEASURE INDIVIDUAL LEVEL ERP ASSIMILATION

Case evidence has shown the important role of individual level assimilation of ERP technology in realizing the business value of implemented ERP systems. However, empirical research in this area has been constrained by the lack of a validated scale for measuring individual level ERP assimilation. This study address this limitation by first theoretically conceptualizing three key dimensions through a multi-case study and then following a rigorous development process to validate a formative measurement instrument for individual level ERP assimilation. The findings show that individual level ERP assimilation consists of width, depth, and innovation, and the proposed measurement instrument is reliable and meets the validity requirements

UNDERSTANDING INDIVIDUAL LEVEL ERP ASSIMILATION FROM A SOCIAL NETWORK PERSPECTIVE: A MULTI-CASE STUDY

Prior research on ERP assimilation has primarily focused on influntial factors at the organizational level. In this study, we attempt to extend our understanding of individual level ERP assimilation from the perspective of social network theory. We designed a multi-case study to explore the relations between ERP users´ social networks and their levels of ERP assimilation based on the three dimensions of the social networks. We gathered data through interviews with 26 ERP users at different levels in five companies. Qualitative analysis was used to understand the effects of social networks and individual interactive learning. We found that user social networks play a significant role in individual level ERP assimilation through interactive learning behaviours among users. We also found five key factors that facilitate users´ assimilation of ERP knowledge: homogeneity (age, position and rank), tie content (instrumental and expressive ties), tie strength, external ties, and centrality. Our research has significant implications for managing assimilation of ERP systems and improving users´ ERP assimilation level in organizations

COMPREHENSIVE UNDERSTANDING THE INHIBITORS AND ENABLERS OF KNOWLEDGE TRANSFER IN ERP ASSIMILATIONS: A MULTI-CASE STUDY

In the enterprise resource planning (ERP) assimilation process, organizations are increasingly concerned about how to ensure employees to have sufficient ERP knowledge effectively. However, limited attention has been directed toward examining knowledge transfer in the assimilation stage systematically. In particular, a significant omission is to understand the key enablers and inhibitors of employees’ learning intention who may receiver knowledge passively in the mandatory setting. We employed a multi-case study method in this exploratory research by interviewing 33 ERP users at all levels in nine big-size firms in China. Results of this analysis suggested that causal ambiguity in new systems, incumbent system habit, and technostress significantly undermined recipients’ learning intentions. Meanwhile, perceived management support, relation embeddedness, and symbolic adoption were key determinants of increased their learning intentions. This study is arguably the first that attempts to look into passive knowledge transfer phenomenon in some depth, and extends prior researches in ERP lifecycle by shedding light on the joint influences of enablers and inhibitors in ERP assimilation context

Responses of soil nitrogen mineralization to temperature and moisture in alpine ecosystems on the Tibetan Plateau

AbstractThe responses of soil net nitrogen (N) mineralization to temperature and moisture were investigated in four alpine ecosystems of forest, shrub, meadow and steppe by laboratory incubation method with undisturbed soil cores on the Tibetan Plateau. The results indicated the soil net N mineralization varies greatly between alpine ecosystems. The soil net N mineralization rate in three incubating moisture of forest ecosystem rose markedly, and that of meadow ecosystem rose gently from temperature of 5°C to 35°C, while that of shrub and steppe ecosystems increased from temperature of 5°C to 25°C and reduced from temperature of 25°C to 35°C. At the same incubating temperature, the soil net N mineralization of four alpine ecosystems increased in the middle moisture and deceased in the low or high moisture

DFT study of itinerant ferromagnetism in pp-doped monolayers of MoS2_2

We use density functional theory to explore the possibility of making the semiconducting transition-metal dichalcogenide MoS$_2$ ferromagnetic by introducing holes into the narrow Mo $d$ band that forms the top of the valence band. In the single impurity limit, the repulsive Coulomb potential of an acceptor atom and intervalley scattering lead to a twofold orbitally degenerate effective-mass like $e'$ state being formed from Mo $d_{x^2-y^2}$ and $d_{xy}$ states, bound to the K and K$'$ valence band maxima. It also leads to a singly degenerate $a'_1$ state with Mo $d_{3z^2-r^2}$ character bound to the slightly lower lying valence band maximum at $\Gamma$. Within the accuracy of our calculations, these $e'$ and $a'_1$ states are degenerate for MoS$_2$ and accommodate the hole that polarizes fully in the local spin density approximation in the impurity limit. With spin-orbit coupling included, we find a single ion magnetic anisotropy of $\sim 5\,$meV favouring out-of-plane orientation of the magnetic moment. Pairs of such hole states introduced by V, Nb or Ta doping are found to couple ferromagnetically unless the dopant atoms are too close in which case the magnetic moments are quenched by the formation of spin singlets. Combining these exchange interactions with Monte Carlo calculations allows us to estimate ordering temperatures as a function of the dopant concentration $x$. For $x \sim 9\%$, Curie temperatures as high as 100K for Nb and Ta and in excess of 160K for V doping are predicted. Factors limiting the ordering temperature are identified and suggestions made to circumvent these limitations

Fasudil in Combination With Bone Marrow Stromal Cells (BMSCs) Attenuates Alzheimer\u27s Disease-Related Changes Through the Regulation of the Peripheral Immune System.

Alzheimer\u27s disease (AD) is a chronic progressive neurodegenerative disease. Its mechanism is still not clear. Majority of research focused on the central nervous system (CNS) changes, while few studies emphasize on peripheral immune system modulation. Our study aimed to investigate the regulation of the peripheral immune system and its relationship to the severity of the disease after treatment in an AD model of APPswe/PSEN1dE9 transgenic (APP/PS1 Tg) mice. APP/PS1 Tg mice (8 months old) were treated with the ROCK-II inhibitor 1-(5-isoquinolinesulfonyl)-homo-piperazine (Fasudil) (intraperitoneal (i.p.) injections, 25 mg/kg/day), bone marrow stromal cells (BMSCs; caudal vein injections, 1 × 1