检索结果-南通市图书馆

Rigidity of certain admissible pairs of rational homogeneous spaces of Picard number 1 which are not of the subdiagram type

引用

science China Mathematics 2019年第11期62卷 2335-2354页

作者： Ngaiming mok Department of Mathematics The University of Hong Kong

Recently, mok and Zhang(2019) introduced the notion of admissible pairs(X0, X) of rational homogeneous spaces of Picard number 1 and proved rigidity of admissible pairs(X0, X) of the subdiagram type whenever X0 is nonlinear. It remains unsolved whether rigidity holds when(X0, X) is an admissible pair NOT of the subdiagram type of nonlinear irreducible Hermitian symmetric spaces such that(X0, X) is nondegenerate for substructures. In this article we provide sufficient conditions for confirming rigidity of such an admissible pair. In a nutshell our solution consists of an enhancement of the method of propagation of sub-VMRT(varieties of minimal rational tangents) structures along chains of minimal rational curves as is already implemented in the proof of the Thickening Lemma of mok and Zhang(2019). There it was proven that, for a sub-VMRT structure? : C(s) → s on a uniruled projective manifold(X, K) equipped with a minimal rational component and satisfying certain conditions so that in particular s is "uniruled" by open subsets of certain minimal rational curves on X, for a "good" minimal rational curve ? emanating from a general point x ∈ s, there exists an immersed neighborhood N?of ? which is in some sense "uniruled" by minimal rational curves. By means of the Algebraicity Theorem of mok and Zhang(2019), s can be completed to a projective subvariety Z ? X. By the author’s solution of the Recognition Problem for irreducible Hermitian symmetric spaces of rank 2(2008)and under Condition(F), which symbolizes the fitting of sub-VMRTs into VMRTs, we further prove that Z is the image under a holomorphic immersion of X0 into X which induces an isomorphism on second homology groups. By studying C*-actions we prove that Z can be deformed via a one-parameter family of automorphisms to converge to X0 ? X. Under the additional hypothesis that all holomorphic sections in Γ(X0, TX |X0) lift to global holomorphic vector fields on X, we prove that the admissible pair(X0, X) is rigi

关键词： rational homogeneous spaces rigidity uniruled projective manifolds sub-VMRT structures

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A weak form of beyond endoscopic decomposition for the stable trace formula of odd orthogonal groups

引用

science China Mathematics 2018年第6期61卷 993-1012页

作者： Chung Pang mok Department of Mathematics Purdue University

We show that the cuspidal component of the stable trace formula of a split special odd orthogonal group over a number field, satisfies a weak form of beyond endoscopic decomposition. We also study the r-stable trace formula, when r is the standard or the second fundamental representation of the dual group, and show that they satisfy a similar kind of beyond endoscopic decomposition. The results are consequences of Arthur's works(2013) on endoscopic classification of automorphic representations, together with known results concerning a class of Langlands L-functions for special odd orthogonal groups.

关键词： cuspidal component stable trace formula beyond endoscopic decomposition r-stable trace formula

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Characterization of standard embeddings between complex Grassmannians by means of varieties of minimal rational tangents

引用

science China Mathematics 2008年第4期51卷 660-684页

作者： mok Ngaiming Department of Mathematics The University of Hong Kong

In 1993, Tsai proved that a proper holomorphic mapping f: Ω → Ω′ from an irreducible bounded symmetric domain Ω of rank ? 2 into a bounded symmetric domain Ω′ is necessarily totally geodesic provided that r′:= rank(Ωg’) ? rank(Ω):= r, proving a conjecture of the author’s motivated by Hermitian metric rigidity. As a first step in the proof, Tsai showed that df preserves almost everywhere the set of tangent vectors of rank 1. Identifying bounded symmetric domains as open subsets of their compact duals by means of the Borel embedding, this means that the germ of f at a general point preserves the varieties of minimal rational tangents (VMRTs).In another completely different direction Hwang-mok established with very few exceptions the Cartan-Fubini extension priniciple for germs of local biholomorphisms between Fano manifolds of Picard number 1, showing that the germ of map extends to a global biholomorphism provided that it preserves VMRTs. We propose to isolate the problem of characterization of special holomorphic embeddings between Fano manifolds of Picard number 1, especially in the case of classical manifolds such as rational homogeneous spaces of Picard number 1, by a non-equidimensional analogue of the Cartan-Fubini extension principle. As an illustration we show along this line that standard embeddings between complex Grassmann manifolds of rank ? 2 can be characterized by the VMRT-preserving property and a non-degeneracy condition, giving a new proof of a result of Neretin’s which on the one hand paves the way for far-reaching generalizations to the context of rational homogeneous spaces and more generally Fano manifolds of Picard number 1, on the other hand should be applicable to the study of proper holomorphic mappings between bounded domains carrying some form of geometric structures.

关键词： minimal rational curves varieties of minimal rational tangents analytic continuation rigidity bounded symmetric domains proper holomorphic maps 14J45 32M15 32H35 53C10

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On compact splitting complex submanifolds of quotients of bounded symmetric domains

引用

science China Mathematics 2017年第6期60卷 1057-1076页

作者： mok Ngaiming NG suiChung Department of Mathematics The University of Hong Kong Department of Mathematics Shanghai Key Laboratory of PMMPEast China Normal University

We study compact complex submanifolds s of quotient manifolds X =Ω/F of irreducible bounded symmetric domains by torsion free discrete lattices of automorphisms, and we are interested in the characterization of the totally geodesic submanifolds among compact splitting complex submanifolds s C X, i.e., under the assumption that the tangent sequence over s splits holomorphically. We prove results of two types. The first type of results concerns s C X which are characteristic complex submanifolds, i.e., embedding Ω as an open subset of its compact dual manifold M by means of the Borel embedding, the non-zero （1, 0）-vectors tangent to s lift under a local inverse of the universal covering map π → X to minimal rational tangents of M. We prove that a compact characteristic complex submanifold s C X is necessarily totally geodesic whenever s is a splitting complex submanifold. Our proof generalizes the case of the characterization of totally geodesic complex submanifolds of quotients of the complex unit ball B^n obtained by mok （2005）. The proof given here is however new and it is based on a monotonic property of curvatures of Hermitian holomorphic vector subbundles of Hermitian holomorphic vector bundles and on exploiting the splitting of the tangent sequence to identify the holomorphic tangent bundle Ts as a quotient bundle rather than as a subbundle of the restriction of the holomorphic tangent bundle Tx to s. The second type of results concerns characterization of total geodesic submanifolds among compact splitting complex submanifolds s C X deduced from the results of Aubin （1978） and yau （1978） which imply the existence of Kahler-Einstein metrics on s C X. We prove that compact s- plitting complex submanifolds s C X of sufticiently large dimension （depending on ） are necessarily totally geodesic. The proof relies on the Hermitian-Einstein property of holomorphic vector bundles associated to Ts, which implies that endomorphisms of such bundles are parallel, and the co

关键词： bounded symmetric domains tangent sequence splitting complex submanifolds varieties of minimal rational tangents K/ihler-Einstein metrics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

studies on Nitrogen Oxides Removal Using Plasma Assisted Catalytic Reactor

引用

Plasma science and Technology 2003年第6期5卷 2057-2062页

作者： V.Ravi young sun mok B.s.Rajanikanth Ho-Chul Kang Department of High Voltage Engineering Indian Institute of Science Bangalore-560 012IndiaDepartment of Chemical EngineeringCheju National UniversityAraCheju 690-756South KoreaDepartment of High Voltage EngineeringIndian Institute of Science Bangalore-560 012IndiaDepartment of Chemical EngineeringCheju National UniversityAraCheju 690-756South Korea

An electric discharge plasma reactor combined with a catalytic reactor wasstudied for removing nitrogen oxides. To understand the combined process thoroughly, dischargeplasma and catalytic process were separately studied first, and then the two processes were combinedfor the study. The plasma reactor was able to oxidize NO to NO_2 well although the oxidation ratedecreased with temperature. The plasma reactor alone did not reduce the NO_x (NO+NO_2) leveleffectively, but the increase in the ratio of NO_2 to NO as a result of plasma discharge led to theenhancement of NO_x removal efficiency even at lower temperatures over the catalyst surface(V_2O_5-WO_3/TiO_2). At a gas temperature of 100℃, the NO_x removal efficiency obtained using thecombined plasma catalytic process was 88% for an energy input of 36 eV/molecule or 30 J/l.

关键词： non-thermal plasma catalytic process oxidation NO_x removal

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Factorization of proper holomorphic maps on irreducible bounded symmetric domains of rank≥2

引用

science China Mathematics 2010年第3期53卷 813-826页

作者： mok Ngaiming NG sui-Chung Department of Mathematics The University of Hong Kong

We obtain rigidity results on arbitrary proper holomorphic maps F from an irreducible bounded symmetric domain Ω of rank ≥2 into any complex space Z. After lifting to the normalization of the subvariety F (Ω) Z, we prove that F must be the canonical projection map to the quotient space of Ω by a finite group of automorphisms. The approach is along the line of the works of mok and Tsai by considering radial limits of bounded holomorphic functions derived from F and proving that proper holomorphic maps between bounded symmetric domains preserve certain totally geodesic subdomains. In contrast to the previous works, in general we have to deal with multivalent holomorphic maps for which Fatou’s theorem cannot be applied directly. We bypass the difficulty by devising a limiting process for taking radial limits of correspondences arising from proper holomorphic maps and by elementary estimates allowing us to define distinct univalent branches of the underlying multivalent map on certain subsets. As a consequence of our rigidity result, with the exception of Type-IV domains, any proper holomorphic map f : Ω→ D of Ω onto a bounded convex domain D is necessarily a biholomorphism. In the exceptional case where Ω is a Type-IV domain, either f is a biholomorphism or it is a double cover branched over a totally geodesic submanifold which can be explicitly described.

关键词： bounded symmetric domain proper holomorphic map Fatou’s theorem correspondence discriminant G-structure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

second fundamental forms of holomorphic isometries of the Poincar disk into bounded symmetric domains and their boundary behavior along the unit circle

引用

science China Mathematics 2009年第12期52卷 2628-2646页

作者： mok Ngaiming NG sui Chung Department of Mathematics The University of Hong Kong

Motivated by problems arising from Arithmetic Geometry,in an earlier article one of the authors studied germs of holomorphic isometries between bounded domains with respect to the Bergman *** the case of a germ of holomorphic isometry f:(Δ,λ ds 2Δ ;0) → (Ω,ds 2Ω ;0) of the Poincar disk Δ into a bounded symmetric domain Ω C N in its Harish-Chandra realization and equipped with the Bergman metric,f extends to a proper holomorphic isometric embedding F:(Δ,λ ds 2Δ) → (Ω,ds 2Ω) and Graph(f) extends to an affine-algebraic variety V  C × C *** of F which are not totally geodesic have been *** arise primarily from the p-th root map ρ p:H → H p and a non-standard holomorphic embedding G from the upper half-plane to the siegel upper half-plane H 3 of genus *** the current article on the one hand we examine second fundamental forms σ of these known examples,by computing explicitly σ *** the other hand we study on the theoretical side asymptotic properties of σ for arbitrary holomorphic isometries of the Poincar disk into *** such mappings expressing via the inverse Cayley transform in terms of the Euclidean coordinate τ=s + it on the upper half-plane H,we have φ(τ)=t 2 u(τ),where u t=0 ≡ *** show that u must satisfy the first order differential equation u t | t=0 ≡ 0 on the real axis outside a finite number of points at which u is *** a by-product of our method of proof we show that any non-standard holomorphic isometric embedding of the Poincar disk into the polydisk must develop singularities along the boundary *** equation φuφt | t=0 ≡ 0 along the real axis for holomorphic isometries into polydisks distinguishes the latter maps from holomorphic isometries into siegel upper half-planes arising from *** the end of the article we formulate characterization problems for holomorphic isometries suggested both by the theoretical and the computational results of the article.

关键词： holomorphic isometry Poincar disk siegel upper half-plane second fundamental form asymptotics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Influence of the wastewater composition on denitrification and biological P-removal in the s-DN-P process: (c) Dissolved and undissolved substrates

引用

Journal of Environmental sciences 2009年第8期21卷 1074-1079页

作者： Hee-Jeong Choi Chul-Ho Choi seung-mok Lee Diwakar Tiwari Department of Environmental Engineering Kwandong University Department of Chemistry School of Physical Sciences Mizoram University

The denitdfication and P-removal in the sorption-denitrification-P-removal （s-DN-P） process were carded out under various wastewater compositions. It is noted that P-removal largely depends on the wastewater composition as well to the quantity of the substrates present in wastewater fraction. Three different wastewater fractions are obtained as： raw wastewater, dissolved wastewater （obtained with filtration using 0.45 μm filter）, and undissolved wastewater （i.e., infiltrate obtained by above filtration）. The ratio of P-release/CODtotal-consumption clearly inferred that undissolved wastewater possess very low value i.e., 0.0008 followed by raw wastewater 0.008 and dissolved wastewater 0.03. When this ratio was nearby 0.01, enhanced P-removal was observed. Moreover, the ratio of P-uptake to NO3^--N decomposition for raw wastewater was two times for dissolved wastewater. Interestingly, it was observed that the P-removal and denitrification depend not only on the dissolved substrates but also the undissolved substrates present in the wastewater. The result of the P-removal obtained with this s-DN-P process did not show a big difference of 36%, 34% and 30%, respectively, for raw, dissolved and undissolved wastewater.

关键词： denitrification polyhydroxybutyrate sequencing batch biofilm reactor sorption denitrification P-removals

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Distributed Virtual Inertia Based Control of Multiple Photovoltaic systems in Autonomous Microgrid

引用

IEEE/CAA Journal of Automatica sinica 2017年第3期4卷 512-519页

作者： Won-sang Im Cheng Wang Wenxin Liu Liming Liu Jang-mok Kim Lehigh University IEEE ABB Inc. Pusan National University

The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the *** an autonomous renewable microgrid usually has much smaller inertia,the control system must be very fast and accurate to fight against the small inertia and *** reduce the demanding requirements on control,this paper proposes to increase the inertia of photovoltaic(PV) system through inertia *** inertia emulation is realized by controlling the charging/discharging of the direct current(DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or *** well designing the inertia,the DC-link capacitor parameters and the control range,the negative impact of inertia emulation on energy efficiency can be *** proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation *** studies demonstrate the effectiveness of the proposed solution.

关键词： Inertia emulation microgrid photovoltaic system renewable energy voltage source converter

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Promoting Entrepreneurship and Innovation in China:Enhancing Research and Transforming University Curriculum

引用

Frontiers of Education in China 2013年第2期8卷 173-197页

作者： Ka Ho mok KAN yue College of Education Zhejiang UniversityHangzhou 310007China Department of Asian and Policy studies The Hong Kong Institute of EducationHong KongChina

In the last three decades or so,China has managed to become the second largest economy in the world,especially after engaging in economic reforms since the late *** being a“world factory”and playing a very significant role in manufacturing products and exporting to different parts of the globe,the Chinese government has realized that depending upon this production mode cannot sustain the country’s long term economic growth and ***,the Chinese government has tried to invest more in advancing technology,research and innovation,knowledge transfer,and promoting entrepreneurship *** article sets out to critically examine the major strategies and policies that the Chinese government has adopted in promoting entrepreneurship and innovation against the wider policies outlined above,with a focused reflection given to the major challenges facing Chinese universities during the process of promoting entrepreneurship and innovation,and entrepreneurship education.

关键词： entrepreneurship education promotion of innovation higher education China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：