检索结果-南通市图书馆

Real hypersurfaces in the complex quadric with commuting Ricci tensor

在线全文

学校读者我要写书评

暂无评论

science China Mathematics 2016年第11期59卷 2185-2198页

作者： sUH YoungJin hwang DooHyun Department of Mathematics Kyungpook National University

We introduce the notion of commuting Ricci tensor for real hypersurfaces in the complex quadric Qm = sOm＋2/sOmsO2. It is shown that the commuting Ricci tensor gives that the unit normal vector field N becomes -principal or -isotropic. Then according to each case, we give a complete classification of Hopf real hypersurfaces in Qm = sOm＋2/sOmsO2 with commuting Ricci tensor.

关键词： commuting Ricci tensor -isotropic -principal kahler structure complex conjugation complex quadric

New multi-phonon gamma vibrational bands in A～110 neutron-rich nuclei

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2011年第S1期54卷 44-48页

作者： HAMILTON J H RAMAYYA A V RAsMUssEN J O hwang J k YEOH E Y Department of Physics Vanderbilt University Nashville TN 37235 USA Lawrence Berkeley National Laboratory Berkeley CA 94720 USA Department of Physics Tsinghua University Beijing 100084 China

The high spin states of neutron-rich 103Nb, 107Tc and 109Tc nuclei in A^110 region have been investigated by measuring prompt γ-γ-γ coincident measurements populated with the spontaneous fission of 252Cf with the Gammasphere detector array. In 103Nb, one-phonon k = 9/2 and two-phonon k = 13/2 γ-vibrational bands have been identified. In 107Tc and 109Tc, one-phonon k = 11/2 and two-phonon k = 15/2 γ-vibrational bands, in which the zero-phonon bands are based on k=7/2 excited states, have also been identified. The two-phonon bands are first observed in odd-Z nuclei. The characteristics for these band structures have been discussed.

关键词： high spin states neutron-rich nucleus γ-vibrational bands

Broadband nonreciprocal thermal emissivity and absorptivity

在线全文

学校读者我要写书评

暂无评论

Light(science & Applications) 2024年第9期13卷 1820-1827页

作者： komron J.shayegan Jae s.hwang Bo Zhao Aaswath P.Raman Harry A.Atwater Thomas J.Watson Laboratory of Applied Physics California Institute of TechnologyPasadenaCAUSA Department of Electrical Engineering California Institute of TechnologyPasadenaCAUSA Department of Materials science and Engineering University of CaliforniaLos AngelesLos AngelesCAUSA Department of Mechanical Engineering University of HoustonHoustonTXUSA

A body that violates kirchhoff’s law of thermal radiation exhibits an inequality in its spectral directional absorptivity and *** such an inequality is of fundamental interest as well as a prerequisite for achieving thermodynamic limits in photonic energy conversion1 and radiative *** far,inequalities in the spectral directional emissivity and absorptivity have been limited to narrow spectral resonances3,or wavelengths well beyond the infrared *** the gap from basic demonstrations to practical applications requires control over a broad spectral range of the unequal spectral directional absorptivity and *** this work,we demonstrate broadband nonreciprocal thermal emissivity and absorptivity by measuring the thermal emissivity and absorptivity of gradient epsilon-near-zero InAs layers of subwavelength thicknesses(50 nm and 150 nm)with an external magnetic *** effect occurs in a spectral range(12.5–16μm)that overlaps with the infrared transparency window and is observed at moderate(1 T)magnetic fields.

关键词： field. reciprocal thermal

Effective I/O scheme Based on RTP for Multimedia Communication systems

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

Journal of Computer science & Technology 2006年第6期21卷 989-996页

作者： Nam-sup Park Chong-sun hwang Department of Computer science and Engineering Korea Univcrsity Seoul Korea

The prime standard for audio/video transport in IP networks is the Real-time Transport Protocol （RTP） and it is targeted at useful services for the transport of real-time multimedia data. RTP was originally designed for use in multicast conferences, using the lightweight sessions model. RTP （in particular, the data part） is so tightly coupled to the application that a number of people have developed libraries that implement RTP. However, little is known about the RTP overheads between user area and kernel area within operating systenl. Actually, unnecessary copying between user area and kernel area lowers the system efficiency. In this paper, we present the design and implementation of Enhanced Multimedia Input/Output scheme based on LINUX. We brought focus to the crossover architecture supporting RTP. Our contributions are able to be summarized into two components： 1） Enhanced Input/Output （EIO） scheme based on LINUX improves the transmission speed by reducing the overheads generated from data copy and context switch between user area and kernel area. And this enables server-based system to transport multimedia data more efficiently. 2） Furthermore, Enhanced Input/Output scheme with RTP （EIORTP） scheme supports efficient multimedia data transmission architecture. The two schemes improve the performance of massive multimedia data transmission.

关键词： kernel area system call EIO RTP EIORTP

Numerical simulation of solidification morphologies of Cu-0.6Cr casting alloy using modified cellular automaton model

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

Transactions of Nonferrous Metals society of China 2010年第6期20卷 1072-1077页

作者： TsAI De-chang hwang Weng-sing Department of Materials science and Engineering National Cheng Kung University

The purpose of this study is to predict the morphologies in the solidification process for Cu-0.6Cr(mass fraction,%)alloy by vacuum continuous casting(VCC)and verify its accuracy by the observed experimental *** numerical simulation aspect, finite difference(FD)method and modified cellular automaton(MCA)model were used to simulate the macro-temperature field, micro-concentration field,nucleation and grain growth of Cu-0.6Cr alloy using real data from actual casting *** the observed casting experiment,the preliminary grain morphologies are the directional columnar grains by the VCC *** solidification morphologies by MCAFD model are in agreement with the result of actual casting experiment well.

关键词： Cu-Cr alloy vacuum continuous casting solidification morphology simulation modified cellular automaton model finite difference method

Manipulating the nonlinearity of transition-metal dichalcogenide polaritons

在线全文

学校读者我要写书评

暂无评论

Light(science & Applications) 2023年第12期12卷 2540-2542页

作者： Min-soo hwang Hong-Gyu Park Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul 08826Republic of Korea

The lithographically designed potential wells in monolayer Ws2 microcavities are utilized to manipulate nonlinear transition-metal dichalcogenide polaritons and enhance the polariton-reservoir interaction strength.

关键词： strength. polar transition

Measurement of alumina film induced ablation of internal insulator in solid rocket environment

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

Defence Technology（防务技术） 2023年第11期29卷 181-192页

作者： Ji-Yeul Bae In s.k.hwang Yoongoo kang Agency for Defense Development 160488th Bukyuseong-streetDaejeonSouth Korea

This study investigates the ablation of internal insulation induced by the deposition of an alumina film with different lateral film speeds.A sub-scale test solid rocket motor(sRM)was designed in an impinging jet configuration to form an alumina film on the sample and to encourage the lateral movement of the film by a high-speed wall *** static fire tests of the test sRM were conducted with six different jet velocities(V_(jet)=100 m/s,150 m/s,200 m/s,268 m/s,330 m/s,and 450 m/s)that indirectly affected the velocity of the wall jet and the deposition rate of alumina *** ablation velocity was deduced from the difference in the sample thickness after a test using a coordinate measuring *** droplet deposition mass flux and wall jet velocity were obtained via two-phase flow simulation with the same jet velocity and effective *** a result,the characteristics of alumina-induced ablation and the changes in ablation with jet velocities were *** area within0.8×jet diameter was focused upon,where the ratio of ablation velocity to incoming alumina mass was constant for each jet velocity,and showed a similarity in jet *** the ablation velocity was increased from 2.05 to 9.98 mm/s with increasing jet velocity,the ratio of the ablation velocity and alumina mass flux decreased from 1.07×10^(-4)to 0.49×10^(-4)m^(3)/kg as Al_(2)O_(3)-C reactions became less efficient with a reduced residence time of the *** the decrease in residence time by the wall jet is more pronounced for slow reactions involved in Al_(2)O_(3)-C reactions,fast reactions in Al_(2)O_(3)-C reactions are less affected and result in a convergence of the volumetric rate of ablation per unit mass of alumina.

关键词： Internal insulation solid rocket motor Ablation Alumina

Multi-party quantum secret sharing based on two special entangled states

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2012年第3期55卷 460-464页

作者： TsAI ChiaWei hwang Tzonelih Computer science and Information Engineering Department National Chengkung University

A multi-party quantum secret sharing protocol using two entangled states, φ0〉 = 1/√2 （1＋）n ＋ 1-）n） and （φ1）1） =1/√2 （1＋）n -1-〉n）, is proposed and analyzed. In this protocol, without requiring to generate any photon or do any local unitary operation, an agent can obtain a shadow of the secret key by simply performing a measurement of single photon. Furthermore, the security of the protocol is analyzed. It shows that no agent can obtain the manager＇s secret without the help of the other agents, and any eavesdropper will be detected if he/she tries to steal the manager＇s secret under ideal or noisy quantum channels.

关键词： entangled state local unitary operation measurement of single photon

Deterministic quantum communication using the symmetric W state

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2013年第10期56卷 1903-1908页

作者： TsAI Chia-Wei hwang Tzonelih smart Network system Institute at Institute for Information Industry Department of Computer science and Information Engineering National Cheng Kung University

This study proposes a new coding function for the symmetric W state. Based on the new coding function, a theoretical protocol of deterministic quanama communication （DQC） is proposed. The sender can use the proposed coding function to encode his/her message, and the receiver can perform the imperfect Bell measurement to obtain the sender＇s message. In comparison to the existing DQC protocols that also use the W class state, the proposed protocol is more efficient and also more practical within today＇s technology. Moreover, the security of this protocol is analyzed to show that any eavesdropper will be detected with a very high probability under both the ideal and the noisy quantum channel.

关键词： deterministic quantum communication symmetric W state imperfect Bell measurement