When a network begins losing nodes or links there is, eventually, a loss in its effectiveness. Thus, a communication network must be constructed to be as stable as possible, not only with respect to tlie initial disruption, but also with respect to the possible reconstruction of the network. When any disruption happens in a cornmunication network two questions are considered: How many vertices can still communicate? How difficult is it to reconnect the network? If a graph is considered as a modeling network, then the above questions can be answered by the graphs. Many graph parameters have been used to deseribe the stability of communication networks, including connectivity, integrity, and tougliness and the binding number. The thorny graphs are special classes of graphs that represent some static interconnection networks. In tliis work, we have given the tenacity of thorny graphs of static interconnection networks.
The tendency for self-superparasitism and it's effects on the quality of the parasitoid Ooencyrtus pityocampae (Mercet) (Hymenoptera: Encyrtidae) in parasitizing a new laboratory host, Philosamia ricini (Danovan) (Lepidoptera: Saturniidae), were investigated. In this study, female parasitoids of various ages (1-, 3- and 5-day-old) were tested individually. Parasitoids were provided with 1-day-old P. ricini eggs at ratios of 5, 10, 20, 30 and 40 host eggs per wasp. The tendency to superparasitize was dependent on the female's age and host density. Five-day-old females showed a strong tendency to superparasitize at low host densities. The development time of wasps in superparasitized eggs was longer than that of wasps in singly parasitized eggs. The size and longevity of adult parasitoids decreased significantly with superparasitism. This work contributes to the development of an efficient mass rearing and laboratory rearing of the parasitoid O. pityocampae using a new host., Hilal Tunca, Maurane Buradino, Etty-Ambre Colombel, Elisabeth Tabone., and Obsahuje bibliografii
Lead zirconatetitanate (PZT) is widely used for its ferroelectric and piezoelectric properties. Its unique properties are conditioned by perovskite structure. Crystallization into this phase is determined among others by a proper stoichiometry, where the lead concentration is a crucial parameter. That is why this paper is devoted to the control of chemical composition of PZT thin films deposited via ion beam sputtering (IBS). Our study showed that the determinative lead content in PZT films prepared by ion-beam sputtering from a multicomponent target can be easily controlled by the power of primary ion source. At the same time, the composition is also dependent on the substrate temperature and the power of assistant ion source. and Olovo zirkonát-titanát (PZT) je široce používaný pro svoje feroelektrické a piezoelektrické vlastnosti, které jsou podmíněny perovskitovou strukturou. Krystalizace PZT do této preferované fáze je podmíněna mimo jiné také správným stechiometrickým složením, kde koncentrace olova je kritickým parametrem. Samotný proces krystalizace probíhá při vysokoteplotním žíhání, při kterém ovšem dochází k nežádoucímu snížení obsahu olova v deponované vrstvě. Proto je dobré připravit vrstvu s přebytkem olova, a tím tak kompenzovat jeho úbytek při žíhání. Z toho důvodu je tento článek zaměřen na řízení chemického složení tenkých filmů PZT pomocí naprašování iontovým svazkem (IBS). Vrstvy nanesené pomocí IBS by měly teoreticky vykazovat stejné chemické složení jaké má terč, z kterého jsou nanášeny. Nicméně, v případě PZT je vhodné mít možnost kontrolovaně měnit chemické složení naprašovaných tenkých filmů pro dosažení vysokého perovskitového podílu. Naše studie odhalila, že určující obsah olova v PZT vrstvách, připravených pomocí jednoduché a duální iontové depozice z vícesložkového terče, může být snadno řízen výkonem primárního iontového zdroje. Složení je také závislé na teplotě substrátu a na energii iontů asistenčního iontového zdroje. Tenké PZT vrstvy byly připraveny s více než 30% přebytkem ze stechiometrického vícesložkového terče (tj. terč bez přebytku olova). Můžeme tedy navrhnout několik možných setů depozičních parametrů vhodných pro depozici PZT pomocí IBS pro dosažení vysokého perovskitového podílu.
At first glance, tensegrity structures give the impression of levitation, but, of course, they do not deny gravity. They are a beautiful example of the application of basic physical laws and applying physical principles in practice. The term tensegrity refers to structures formed by rigid bodies under pressure in a network formed by mechanical tension.
Reduced soil tillage practices are claimed to improve soil health, fertility and productivity through improved soil structure and higher soil organic matter contents. This study compares soil structure stability of soil aggregates under three different tillage practices: conventional, reduced and no tillage. The erosive strength of soil aggregates has been determined using the abrasion technique with the soil aggregate erosion chambers (SAE). During abrasion soil aggregates have been separated into the exterior, transitional and interior regions. The forces needed to remove the material from the aggregate were calculated as erosive strength and compared with the tensile strength of the aggregates derived from crushing tests. The relationship between aggregate strength and other soil properties such as organic carbon and hydrophobic groups’ content has also been identified. The results show that erosive and tensile strength of soil aggregates is very low in topsoil under conventional and reduced tillage comparing with the subsoil horizons. Negative correlation was found between the content of organic carbon, hydrophobic compounds and erosive aggregate strength which suggests that the stabilising effect of soils organic carbon may be lost with drying. The positive relationship between the tensile strength and erosive strength for aggregates of 8–5 mm size suggests that the total strength of these aggregates is controlled by the sum of strength of all concentric layers.
In this paper the tensor products of Hilbert modules over locally $C^{*}$-algebras are defined and their properties are studied. Thus we show that most of the basic properties of the tensor products of Hilbert $C^{*}$-modules are also valid in the context of Hilbert modules over locally $C^{*}$-algebras.