‏‎for the first time nakayama introduced qf-ring. in 1967 carl. faith and elbert a. walker showed that r is qf-ring if and only if each injective right r-module is projective if and only if each injective left r-modules is projective. in 1987 s.k.jain and s.r.lopez-permouth proved that every ring homomorphic images of r has the property that each cyclic s-module is essentialy embeddable in dire...

this study considers the level of increase in customer satisfaction by supplying the variant customer requirements with respect to organizational restrictions. in this regard, anp, qfd and bgp techniques are used in a fuzzy set and a model is proposed in order to help the organization optimize the multi-objective decision-making process. the prioritization of technical attributes is the result ...

the main objective in sampling is to select a sample from a population in order to estimate some unknown population parameter, usually a total or a mean of some interesting variable. a simple way to take a sample of size n is to let all the possible samples have the same probability of being selected. this is called simple random sampling and then all units have the same probability of being ch...

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

this research is about the political economy of china in central asia. in this research the political & economic interactions affected on chinas political economy in central asia are examined. chinas goal of presence in central asia including political-security, economic and energy goals is described in one part. in another part, the trade relations between china and central asian countries ar...