On McCoy modules

Jian Cui,Jianlong Chen 대한수학회 2011 대한수학회보 Vol.48 No.1

Extending the notion of McCoy rings, we introduce the class of McCoy modules. Over a given ring R, it contains the class of Armendariz modules (over R). Some properties of this class of modules are established, and equivalent conditions for McCoy modules are given. Moreover, we study the relationship between a module and its polynomial module. Several known results relating to McCoy rings can be obtained as corollaries of our results.

Quasipolar matrix rings over local rings

Jian Cui,Xiaobin Yin 대한수학회 2014 대한수학회보 Vol.51 No.3

A ring R is called quasipolar if for every a 2 R there exists p2 = p ∈ R such that p ∈ comm2 R(a), a + p ∈ U(R) and ap 2∈Rqnil. The class of quasipolar rings lies properly between the class of strongly π-regular rings and the class of strongly clean rings. In this paper, we determine when a 2 × 2 matrix over a local ring is quasipolar. Necessary and sufficient conditions for a 2 × 2 matrix ring to be quasipolar are obtained.

A NOTE ON STRONGLY *-CLEAN RINGS

Jian Cui,Zhou Wang 대한수학회 2015 대한수학회지 Vol.52 No.4

A *-ring R is called (strongly) *-clean if every element of R is the sum of a projection and a unit (which commute with each other). In this note, some properties of *-clean rings are considered. In particular, a new class of *-clean rings which called strongly π-*-regular are introduced. It is shown that R is strongly π-*-regular if and only if R is π-regular and every idempotent of R is a projection if and only if R/J(R) is strongly regular with J(R) nil, and every idempotent of R/J(R) is lifted to a central projection of R. In addition, the stable range conditions of *-clean rings are discussed, and equivalent conditions among *-rings related to *-cleanness are obtained.

Extensions of linearly McCoy rings

Jian Cui,Jianlong Chen 대한수학회 2013 대한수학회보 Vol.50 No.5

A ring R is called linearly McCoy if whenever linear poly- nomials f(x), g(x) ∈ R[x]\{0} satisfy f(x)g(x) = 0, there exist nonzero elements r, s ∈ R such that f(x)r = sg(x) = 0. In this paper, extension properties of linearly McCoy rings are investigated. We prove that the polynomial ring over a linearly McCoy ring need not be linearly McCoy. It is shown that if there exists the classical right quotient ring Q of a ring R, then R is right linearly McCoy if and only if so is Q. Other basic extensions are also considered.

Optimization of the Phosphorus Doped BSF Doping Profile and Formation Method for N-type Bifacial Solar Cells

Jian Cui,Shihyun Ahn,Nagarajan Balaji,Cheolmin Park,Junsin Yi 한국태양광발전학회 2016 Current Photovoltaic Research Vol.4 No.2

n-type PERT (passivated emitter, rear totally diffused) bifacial solar cells with boron and phosphorus diffusion as p+ emitter and n+ BSF (back surface field) have attracted significant research interest recently. In this work, the influences of wafer thickness, bulk lifetime, emitter, BSF on the photovoltaic characteristics of solar cells are discussed. The performance of the solar cell is determined by using one-dimensional solar cell simulation software PC1D. The simulation results show that the key role of the BSF is to decrease the surface doping concentration reducing the recombination and thus, increasing the cell efficiency. A lightly phosphorus doped BSF (LD BSF) was experimentally optimized to get low surface dopant concentration for n type bifacial solar cells. Pre-oxidation combined with a multi-plateau drive-in, using limited source diffusion was carried out before pre-deposition. It could reduce the surface dopant concentration with minimal impact on the sheet resistance.

Extensions of linearly McCoy rings

Cui, Jian,Chen, Jianlong Korean Mathematical Society 2013 대한수학회보 Vol.50 No.5

A ring R is called linearly McCoy if whenever linear polynomials $f(x)$, $g(x){\in}R[x]{\backslash}\{0\}$ satisfy $f(x)g(x)=0$, there exist nonzero elements $r,s{\in}R$ such that $f(x)r=sg(x)=0$. In this paper, extension properties of linearly McCoy rings are investigated. We prove that the polynomial ring over a linearly McCoy ring need not be linearly McCoy. It is shown that if there exists the classical right quotient ring Q of a ring R, then R is right linearly McCoy if and only if so is Q. Other basic extensions are also considered.

로봇 저널리즘 연구 동향 및 미래 전망

Cui, Jian-Dong,Song, Seung-keun 한국정보통신학회 2020 한국정보통신학회논문지 Vol.24 No.2

AI-powered robot news is drawing attention as artificial intelligence technology is fully spread in the news distribution field. Robot news still has many technical and ethical problems, but academic research on this is insufficient. This study analyzes the issue of robot writing in artificial intelligent based robot journalism industry using SWOT analysis. As a result, the advantages of big data processes, accurate information gathering, high efficiency and disadvantages such as lack of independent arguments and lack of evidence and opportunities for technical development, government support, academic development, and industrial applications, and threats such as uncritical acceptance and lack of talent have been found. This study suggests three future-oriented directions, such as human-machine collaboration, intelligent news, and chat-bot, through previous studies on the development direction of robot journalism-based article writing.

A NOTE ON STRONGLY *-CLEAN RINGS

CUI, JIAN,WANG, ZHOU Korean Mathematical Society 2015 대한수학회지 Vol.52 No.4

A *-ring R is called (strongly) *-clean if every element of R is the sum of a projection and a unit (which commute with each other). In this note, some properties of *-clean rings are considered. In particular, a new class of *-clean rings which called strongly ${\pi}$-*-regular are introduced. It is shown that R is strongly ${\pi}$-*-regular if and only if R is ${\pi}$-regular and every idempotent of R is a projection if and only if R/J(R) is strongly regular with J(R) nil, and every idempotent of R/J(R) is lifted to a central projection of R. In addition, the stable range conditions of *-clean rings are discussed, and equivalent conditions among *-rings related to *-cleanness are obtained.

On McCoy modules

Cui, Jian,Chen, Jianlong Korean Mathematical Society 2011 대한수학회보 Vol.48 No.1

Extending the notion of McCoy rings, we introduce the class of McCoy modules. Over a given ring R, it contains the class of Armendariz modules (over R). Some properties of this class of modules are established, and equivalent conditions for McCoy modules are given. Moreover, we study the relationship between a module and its polynomial module. Several known results relating to McCoy rings can be obtained as corollaries of our results.

Optimization of the Phosphorus Doped BSF Doping Profile and Formation Method for N-type Bifacial Solar Cells

Cui, Jian,Ahn, Shihyun,Balaji, Nagarajan,Park, Cheolmin,Yi, Junsin Korea Photovoltaic Society 2016 Current Photovoltaic Research Vol.4 No.2

n-type PERT (passivated emitter, rear totally diffused) bifacial solar cells with boron and phosphorus diffusion as p+ emitter and n+ BSF (back surface field) have attracted significant research interest recently. In this work, the influences of wafer thickness, bulk lifetime, emitter, BSF on the photovoltaic characteristics of solar cells are discussed. The performance of the solar cell is determined by using one-dimensional solar cell simulation software PC1D. The simulation results show that the key role of the BSF is to decrease the surface doping concentration reducing the recombination and thus, increasing the cell efficiency. A lightly phosphorus doped BSF (LD BSF) was experimentally optimized to get low surface dopant concentration for n type bifacial solar cells. Pre-oxidation combined with a multi-plateau drive-in, using limited source diffusion was carried out before pre-deposition. It could reduce the surface dopant concentration with minimal impact on the sheet resistance.