The cylindrical shell is one of the main structural parts in ocean engineering structures.These cylinders are mostly of medium length,which means that the radius of the cross section is significantly smaller than the ...The cylindrical shell is one of the main structural parts in ocean engineering structures.These cylinders are mostly of medium length,which means that the radius of the cross section is significantly smaller than the length of the cylindrical shell.From the viewpoint of the shell theory,they belong to the mid-long cylindrical shell category.To solve mechanical problems on this kind of structure,especially a cracked cylindrical shell,analysis based on shell theory is necessary.At present the generally used solving system for the mid-long cylindrical shell is too complicated,difficult to solve,and inapplicable to engineering.This paper introduced the Sanders' mid-long cylindrical shell theory which reduces the difficulty of the solution process,and will be suitable for solving problems with complicated boundary conditions.On this basis,the engineering applications of this theory were discussed in conjunction with the problem of a mid-long cylindrical shell having a circumferential crack.The solution process is simple,and the closed form solution can usually be found.In practical engineering applications,it gives satisfactory precision.展开更多
The increased production efficiency of heat treatable A1 alloys, as the result of applied electromagnetic field during continuous casting process was investigated. The applied frequency of the electromagnetic field （...The increased production efficiency of heat treatable A1 alloys, as the result of applied electromagnetic field during continuous casting process was investigated. The applied frequency of the electromagnetic field （EMF） during the AI alloys continuous casting was changing from 30 Hz to 50 Hz, while some castings were obtained without the EMF influence. The mechanical characterization of continuous casted AI alloys EN AW 2007 and En AW 2024 was done on testing machine Zwick/Roell Z 100. The microstructure of as-cast samples was examined, as well. When the frequency decreases （from 50 Hz to 30 Hz）, the grain size decreases as well, what is noticeable through the finer microstructure and its uniformity throughout the cross-section. These results have shown that low frequency electromagnetic field significantly influenced the microstructure and therefore the mechanical properties of as cast ingots. Thus, through improved castings quality, operation time and energy savings, the production efficiency was increased.展开更多
Brick and tile were originally the building components for meeting a certain function, and have been widely applied to the field of the interior design today through designer＇ s unique understanding and constant desi...Brick and tile were originally the building components for meeting a certain function, and have been widely applied to the field of the interior design today through designer＇ s unique understanding and constant design thinking, so that they are developed into the symbolic signs with the characteristics of traditional Chinese culture. However, ＂function is converted to symbolic sign＂ as a model of thinking is a reflection and return of the traditional culture to the spirit of the times, and it carries forward the essence of the nation.展开更多
The past decade has witnessed a huge increase in the number of proposed middleware solutions for robotic fleets operating in unstructured environments. As a result, it has become difficult to decide which middleware i...The past decade has witnessed a huge increase in the number of proposed middleware solutions for robotic fleets operating in unstructured environments. As a result, it has become difficult to decide which middleware is the most appropriate for a specific application or application domain. In this paper we first extract a set of common and specific challenges that middlewares address, and group them according to the source domain they have originated within. These challenges are derived from a specific precision agriculture use-case based on the robotic fleet for weed control elaborated within the European project RHEA-robot fleets for highly effective agriculture and forestry management. Furthermore, the paper provides an analysis of a number of different middlewares and suggests a set of criteria for systemizing representative solutions. The aim of this analysis is to assist the process of finding an adequate middleware for a specific application domain.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.（50579023）.
文摘The cylindrical shell is one of the main structural parts in ocean engineering structures.These cylinders are mostly of medium length,which means that the radius of the cross section is significantly smaller than the length of the cylindrical shell.From the viewpoint of the shell theory,they belong to the mid-long cylindrical shell category.To solve mechanical problems on this kind of structure,especially a cracked cylindrical shell,analysis based on shell theory is necessary.At present the generally used solving system for the mid-long cylindrical shell is too complicated,difficult to solve,and inapplicable to engineering.This paper introduced the Sanders' mid-long cylindrical shell theory which reduces the difficulty of the solution process,and will be suitable for solving problems with complicated boundary conditions.On this basis,the engineering applications of this theory were discussed in conjunction with the problem of a mid-long cylindrical shell having a circumferential crack.The solution process is simple,and the closed form solution can usually be found.In practical engineering applications,it gives satisfactory precision.
文摘The increased production efficiency of heat treatable A1 alloys, as the result of applied electromagnetic field during continuous casting process was investigated. The applied frequency of the electromagnetic field （EMF） during the AI alloys continuous casting was changing from 30 Hz to 50 Hz, while some castings were obtained without the EMF influence. The mechanical characterization of continuous casted AI alloys EN AW 2007 and En AW 2024 was done on testing machine Zwick/Roell Z 100. The microstructure of as-cast samples was examined, as well. When the frequency decreases （from 50 Hz to 30 Hz）, the grain size decreases as well, what is noticeable through the finer microstructure and its uniformity throughout the cross-section. These results have shown that low frequency electromagnetic field significantly influenced the microstructure and therefore the mechanical properties of as cast ingots. Thus, through improved castings quality, operation time and energy savings, the production efficiency was increased.
文摘Brick and tile were originally the building components for meeting a certain function, and have been widely applied to the field of the interior design today through designer＇ s unique understanding and constant design thinking, so that they are developed into the symbolic signs with the characteristics of traditional Chinese culture. However, ＂function is converted to symbolic sign＂ as a model of thinking is a reflection and return of the traditional culture to the spirit of the times, and it carries forward the essence of the nation.
文摘The past decade has witnessed a huge increase in the number of proposed middleware solutions for robotic fleets operating in unstructured environments. As a result, it has become difficult to decide which middleware is the most appropriate for a specific application or application domain. In this paper we first extract a set of common and specific challenges that middlewares address, and group them according to the source domain they have originated within. These challenges are derived from a specific precision agriculture use-case based on the robotic fleet for weed control elaborated within the European project RHEA-robot fleets for highly effective agriculture and forestry management. Furthermore, the paper provides an analysis of a number of different middlewares and suggests a set of criteria for systemizing representative solutions. The aim of this analysis is to assist the process of finding an adequate middleware for a specific application domain.
