Bragg Reflectors consist of periodic dielectric layers having an optical path length of quarter wavelength for each layer giving them important properties and makes them suitable for optoelectronics applications. The reflectivity can be increased by increasing the number of layers of the mirror to get the required value. For example for an 8 layers Bragg mirror (two layers for each dielectric pair), the contrast of the refractive index has to be equal to 0.275 for reaching reflectivity > 99%. Doubling the number of layers results in a reflectivity of 99.99%. The high reflectivity is purely caused by multiple-interference effects. It can be analyzed by using different matrix methods such as the transfer matrix method (TMM) which is the simplest method to study the characteristic of devices with different alternating layers.
The use of legislation related to electronic contracting, through the adoption of the method of enactment of legislation and legislative intervention, and to be careful and cautious in the issuance of legislative texts that do not adversely affect the business activity, which is taking its steps for the first time on the path of electronic commerce in this new world by the new knowledge of the subject theoretically and practically , With the necessary assistance of legal expertise so that legislation does not constitute barriers and obstacles to the development of electronic commerce.
The aim of the research is to study the biology, life cycles, distribution and structure of the reproductive organ of Leucozonella retteri in natural conditions. Zoological and malacological methods are used in the work. The collection of the material was carried out according to A.A. Shileiko method. According to the results of the conducted studies, the differences between Leucozonella retteri and other species in the structure of the reproductive organ were manifested in the following. The lower part of the sperm is straight, the ovary is slightly curved. The paw pad is 8, located in 4x2 positions. The stylophore is large spherical. The vagina is cylindrical, its length is 5-6 times greater than the width. The penis is large and conve
... Show MoreThe Esterification kinetics of acetic acid with ethanol in the presence of sulfuric acid as a homogenous catalyst was studied with isothermal batch experiments at 50-60°C and at a different molar ratio of ethanol to acetic acid [EtOH/Ac]. Investigation of kinetics of the reaction indicated that the low of [EtOH/Ac] molar ratio is favored for esterification reaction, this is due to the reaction is catalyzed by acid. The maximum conversion, approximately 80% was obtained at 60°C for molar ratio of 10 EtOH/Ac. It was found that increasing temperature of the reaction, increases the rate constant and conversion at a certain mole ratio, that is due to the esterification is exothermic. Activity coefficients were calculated using UNIFAC progra
... Show MoreIn this paper we define and study new generalizations of continuous functions namely, -weakly (resp., w-closure, w-strongly) continuous and the main properties are studies: (a) If f : X®Y is w-weakly (resp., w-closure, w-strongly) continuous, then for any AÌX and any BÌY the restrictions fïA : A®Y and fB : f -1(B)®B are w-weakly (resp., w-closure, w-strongly) continuous. (b) Comparison between deferent forms of generalizations of continuous functions. (c) Relationship between compositions of deferent forms of generalizations of continuous functions. Moreover, we expanded the above generalizations and namely almost w-weakly (resp., w-closure, w-strongly) continuous functions and we state and prove several results concerning it.
The protection of the rights of minorities is primarily an internal issue that depends on the nature of the political system of the state, and it is one of the internal means to reassure minorities and ensure their enjoyment of those rights. It can be a safety valve against the problems that these minorities may raise. that live in our society, but rather work on developing a legal system that can serve as a role model to protect our minorities, which contributed to drawing a picture that reflected the diversity of our society
In contemporary discourses the debate of most Western thinkers is about the efforts to clarify the normative foundations of democracy. And then, some political thinkers have adopted other models differ in terms of standards for traditional liberal democracy. Be the common goal of democracy will give the formation of a greater role than usual in political liberalism rather than limiting the participatory activity of citizens on the function to give permanent legitimacy to the exercise of state authority. The activity is to be permanently enshrined in the democratic public sphere and the issue must be understood as the source of all political decisions.
A survey of chrysidid wasps and an identification key to the genera from different localities in Iraq are provided. The genus Pseudomalus Ashmead, 1902 with Pseudomalus auratus (Linnaeus) and Omalus timidus (Nurse), are new records from Iraq. As well, a preliminary checklist of Iraq’s Chrysididae is suggested. Twenty species within nine genera in two subfamilies have been included in the current list. Historical information is provided together with remarks on the current taxonomic status and the particular validity for some species.
Time is an essential element of contracts، as there is an independent in many parts of each contract، but the time dimension has a significant impact on the provisions of all contracts and is not limited to a particular range of contracts، and French and Arab jurists alike have called for this dimension to be given special attention، and as a result the French legislator has introduced the term duration of the contract، to try to limit the temporal elements، to clarify their provisions and to distinguish between them in decree131/2 016، but for our Arab country it did not receive the appropriate answer. The problem of duration in contracts relates to the lack of clarity of the idea، and then to confuse the various time terms in the
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