(Re)defining Esotericism

Studies stability properties of linear time-invariant delay systems. The specific notion under consideration is asymptotic stability independent of delay. As an attempt to achieve a compromise between the complexity and tightness of various stability tests, the authors present a number of sufficient stability conditions which improve several previously available sufficient conditions and which are also much easier to verify than the known necessary and sufficient conditions.

The structure, stability and electronic property of the AuGe n (n = 2–13) clusters with different spin configurations are systematically investigated with density-functional theory approach at UB3LYP/LanL2DZ level. In examining the lowest energy structures, it is found that the growth behaviors for the small-sized AuGe n (n = 2–9) clusters and relatively large-sized AuGe n (n = 10–13) clusters are different. As the number of Ge atom increases, the Au atom would gradually move from convex to surface and to interior sites. For the most stable structures of AuGe n (n = 10–13) clusters, the Au atom would be completely surrounded by the Ge atoms to form Au-encapsulated Ge n cages. Natural population analysis shows that the charges always transfer from the Au atom to the Ge n framework except for the AuGe2 cluster. This indicates that the Au atom acts as electron donor even the 5d orbitals of the Au atom are not significantly involved in chemical bonding. The analyses of the average atomic binding energies as well as the dissociation energies and the second-order differences of total energy show that the AuGe n clusters with n = 5, 9 and 12 are more stable than their neighboring ones, in which the bicapped pentagonal prism AuGe12 in D 2d symmetry is most stable. The highest occupied molecular orbital–lowest unoccupied molecular orbital gaps are explored to be in the region of semiconductors and the more stable clusters have slightly smaller gaps. It could be expected that the stable clusters might be considered as the novel building blocks in practical applications, e.g., the cluster-assembled semiconductors or optoelectronic material.

Homeostatic property clusters (HPCs) are offered as a way of understanding natural kinds, especially biological species. I review the HPC approach and then discuss an objection by Ereshefsky and Matthen, to the effect that an HPC qua cluster seems ill-fitted as a description of a polymorphic species. The standard response by champions of the HPC approach is to say that all members of a polymorphic species have things in common, namely dispositions or conditional properties. I argue that this response fails. Instances of an HPC kind need not all be similar in their exhibited properties. Instead, HPCs should instead be understood as unified by the underlying causal mechanism that maintains them. The causal mechanism can both produce and explain some systematic differences between a kind’s members. An HPC kind is best understood not as a single cluster of properties maintained in stasis by causal forces, but as a complex of related property clusters kept in relation by an underlying causal process. This approach requires recognizing that taxonomic systems serve both explanatory and inductive purposes.

The research is devoted to the analysis of phraseological units of Russian and English which include the name of the element water. The beginning of the paper represents a review of research works devoted to the investigation of the element. Most of the works appear to be cognitive studies of the element water making use of the field method in considering material by forming semantic fields which include a certain number of language units. The specific feature of the present paper consists in analysing the name of the element water itself. The aim of the present paper is to distinguish semantic (semiotic) manifestations of the element water as part of idioms; to reveal the aspects of human life the element correlates with; to consider the image potential of the element water in its phraseological embodiment, to reveal its cultural connotations. The empirical material includes 39 Russian and 33 English idioms from reliable lexicography sources which were analyzed. To achieve the aim the introspective method together with the parallel analysis of the actual idiom meaning and its inner form, taking into consideration historical etymology data, was applied. Methodology of the paper rests upon the generally accepted fact that meanings of idioms are based on connotations (particularly cultural) of their parts or situations described in them. It is obvious that cultural connotations can be revealed from a word and serve as a motive to the appearance of an idiom in case the word is a symbol recognized in this culture. To determine the notional characteristics of the term analysis of the works devoted to symbol and symbolic meanings of words (A.F. Losev, Yu.M. Lotman, N.D. Arutyunova, M.L. Kovshova, Ts. Todorov, A.V. Medvedeva, D.A. Tarakanova) was undertaken. According to the analysis the basic and interconnected characteristics distinguishing the notion of symbol are: 1) sign nature, 2) belonging to the sphere of culture, 3) generalisation, 4) similarity between form and content, 5) ability to be recognised by native speakers. Sharing ideas of A.N. Bara-nov and D.O. Dobrovolsky who consider the feature, i.e. direct or indirect belonging to the world of things, to be the most important feature of a symbol, the author agrees with their classification that includes four groups of symbol categories in language and culture: 1) symbols of culture, 2) symbols of language, 3) cultural and language symbols simultaneously, 4) non-productive language symbols. Based on the described methodology analysis of the material made it possible to identify classes of phraseological units including the component water joint with symbolic / property meanings. Section of phraseological units including idioms with symbolic representations of the element water consists of four main groups and four subgroups. Section with non-symbolic (property) representations of the element water consists of seven main groups and three subgroups. According to the results of the research a conclusion about the high degree of semantic development of the element water in Russian and English language cultures was made. In its symbolic and non-symbolic aspects the element water reflects various spheres of human existence such as: Life, Time, Truth, Space, Purity; it corresponds with the ethic, aesthetic values of people, with some aspects of agricultural activities, with features of human character. Specific for Russian language culture are the images of water connected with where evil spirits live, for English language culture the images of water as material values and the water body to travel in a vessel.

The robust stability problem of linear discrete singular time-delay systems with structured (elemental) parameter uncertainties is investigated. Under the assumptions that the nominal discrete singular time-delay system is regular, impulse-free and asymptotically stable, some new sufficient conditions are proposed to preserve the assumed properties when structured (elemental) parameter uncertainties are added into the nominal discrete singular time-delay system. Further new sufficient conditions are also proposed for guaranteeing that the linear discrete singular time-delay system with both structured (elemental) and unstructured (norm-bounded) parameter uncertainties has the properties of regularity, impulse-immunity and asymptotic stability. Four examples are given to demonstrate the applicability of the proposed sufficient conditions.

The application of fish gelatin (FG) is limited due to its poor mechanical properties and thermal stability, both of which could be significantly improved by gellan gum (GG) found in previous research. However, the FG/GG composite hydrogel was brittle and easily damaged by external forces. It was found that the composite hydrogel with Fe2(SO4)3 showed good flexibility and self-healing properties in the pre-experiment. Thus, the synergistic effect of FG, GG and Fe2(SO4)3 on the mechanical properties of the composite hydrogel was investigated in this study. According to one-way experiments, response surface tests and Texture Profile Analysis, it was found that under the optimum condition of FG concentration 186.443 g/L, GG concentration 8.666 g/L and Fe2(SO4)3 concentration 56.503 g/L, the springiness of the composite cylindrical hydrogel with the height of 25 mm formed in 25 mL beakers (bottom diameter 30 mm) was 7.602 mm. Determination of the rheological properties, compression performance, adhesive performance and self-healing properties showed that the composite hydrogel had good thermal stability, flexibility and self-healing properties with good adhesion, skin compliance and compressive strength, and it was easy to remove. The composite hydrogel showed strong antimicrobial activity against A. salmonicida and V. parahaemolyticus. All hydrogels showed a uniform and porous structure. The 3D structure of the composite hydrogel was much looser and more porous than the pure FG hydrogel. The flexible and self-healing composite hydrogel with some antimicrobial activity is suitable for the development of medical dressings, which broadens the applications of the composite hydrogel.

Intrinsic photothermal phase change materials with enhanced toughness and flexibility for thermal management in extreme environments

Structural, electronic and vibrational properties of GexCy (x+y=2–5) nanoclusters: A B3LYP-DFT study

In this paper, we present a global optimal and stable fuzzy controller design method for both continuous- and discrete-time fuzzy systems under both finite and infinite horizons. First, a sufficient condition is proposed which indicates that the global optimal effect can be achieved by the fuzzily combined local optimal controllers. Based on this sufficient condition, we derive a local concept approach to designing the optimal fuzzy controller by applying traditional linear optimal control theory. The stability of the entire closed-loop continuous fuzzy system can be ensured by the designed optimal fuzzy controller. The optimal feedback continuous fuzzy system can not only be guaranteed to be exponentially stable, but also be stabilized to any desired degree. Also, the total energy of system output is absolutely finite. Moreover, the resultant feedback continuous fuzzy system possesses an infinite gain margin; that is, its stability is guaranteed no matter how large the feedback gain becomes. Two examples are given to illustrate the proposed optimal fuzzy controller design approach and to demonstrate the proved stability properties.

The correspondence between sequential program schemes and formal languages is well known (Blikle and Mazurkiewicz (1972), Engelfriet (1974)). The situation is more complicated in the case of parallel program schemes, and trace languages (Mazurkiewicz (1977)) have been introduced to describe them. We introduce the concept of the closure of a language on a so called independence relation on the alphabet of the language, and formulate several theorems about them and the trace languages. We investigate the closedness properties of Chomsky classes under closure on independence relations, and as a special case we derive a new necessary and sufficient condition for the regularity of the commutative closure of a language.

Due to properties of flexibility, adaptiveness, error tolerance, and time-determinism performance, the FlexRay communication protocol has been widely used to investigate robot systems and new generation of automobiles. In this paper, with the FlexRay communication protocol, the tracking problem of a class of cyber-physical systems are investigated by developing a general hybrid model, in which an emulation controller is utilized. Based on the proposed hybrid model, some sufficient conditions are established to guarantee the convergence of tracking errors. Then, the maximum allowable transmission interval (MATI) of the static/dynamic segment is obtained with a more general formula than the ones in some the previous works. The obtained MATI over the FlexRay communication network can be adjusted via the appropriate length of the static/dynamic segment, which reflects the flexibility of FlexRay. Finally, the results are verified by considering the tracking problem of a single-link robot arm system as well as the stabilization of a batch reactor system.

Output Regulation by Error Dynamic Feedback in Hybrid Linear Systems with State Jumps

Calmness is a restricted form of local Lipschitz continuity where one point of comparison is fixed. We study the calmness of solutions to parameterized optimization problems of the form $$ \min \{f(x,w)\} \hbox{ over all } x \in\reals^{n}, $$ where the extended real-valued objective function f is continuously prox-regular in x with compatible parameterization in w. This model covers most finite-dimensional optimization problems, though we focus particular attention here on the case of parameterized nonlinear programming. We give a second-order sufficient condition for there to exist unique optimal solutions that are calm with respect to the parameter. We also characterize a slightly stronger stability property in terms of the same second-order condition, thus clarifying the gap between our sufficient condition and the calmness property. In the case of nonlinear programming, our results complement a long study of the stability properties of optimal solutions: for instance, one consequence of our results is that the Mangasarian--Fromovitz constraint qualification when paired with a new (and relatively weak) second-order condition ensures the calmness of solutions to parameterized nonlinear programs.

This section is concerned with the application of vector norm based stability analysis techniques developed in another chapter (Borne et al., 1993) of this book. For pedagogical reasons, this paper is restrained to a single class of problems and to a particular class of systems which leads to simple developments. More general processes can be further investigated in the same way but with a heavier technical part (Meizel, 1984) The proposed method is essentially a parametric optimization one. Typically, the considered process model depends upon a time-varying perturbation input and for a constant value of this one, the process model is supposed to be almost linear stationary. The considered stability property is the exponential stability of an equilibrium point. Regarding this property, the “non linear” characteristics stem both from the fact that considered processes are not linear stationary and from the fact that the stability analysis tool gives sufficient conditions which can be more or less restrictive with respect to the intrinsic — but unknown — stability properties of the studied equilibrium. For an a priori chosen control structure, the problem consists in tuning the control parameters and simultaneously in adapting the stability analysis tool so that the stability conditions are the least restrictive possible. This last feature is achieved by using some parametrizations that are obviously efficient on the well-known case of linear stationary processes while keeping the validity of the method for nonlinear systems. This parametrization heuristic leads to the definition of a scalar criterion, almost everywhere differentiable, whose iterative minimization is the design method.

Uniformly convergent hybrid schemes for solutions and derivatives in quasilinear singularly perturbed BVPs