Aiming at the existing relevant problems in cost management for the projects of petrochemical enterprises, this paper includes a large quantity of practical data and summarizes the indicators which influence the cost of projects of petrochemical enterprises into 14 indicators including investment scale, integrated operation, key technologies of pro
The case study aims to understand the influence of social environment on the course of life of children of a commercial sex worker.The participants of the study were two sons of a commercial sex worker who grew up in different environments.The older sibling who is 19 years of age (case 1) lives with his mother, Military UAV whereas the younger sibl
Tuning the mass density and bulk modulus independently is the key to manipulate the propagation of sound wave.Acoustic metamaterials provide a feasible method to realize various acoustic parameters.However, the relevant studies are mainly concentrated in air, and the huge impedance difference makes it difficult to directly extend these airborne str
Interactions within the food chain are essential Disposables to ecosystem ecology.At the same time, very little is known of the trophic relationships between Heteroptera and zooplankton.The aim of this study was to examine the community structure of water bugs in the littoral zone of shallow lakes and their impact on crustacean zooplankton communit