Results 51 to 60 of about 761 (208)

Quadratic forms over fraction fields of two-dimensional henselian rings and Brauer groups of related schemes

, 2000
Let A be an excellent henselian two-dimensional local domain (for the definition of excellent rings, see [EGA IV2], 7.8.2). Let K be its field of fractions and k its residue field. Assume that k is separably closed.
M. Ojanguren, R. Parimala, J.-L. Colliot-Thélène   +2 more
core  

6.1% Volumetric Negative Thermal Expansion Induced by the Reversible Reconstructive Phase Transition in Pb‐Free Bi1−xLnxCoO3 (Ln: Lanthanoid)

Advanced Science, EarlyView.
Perovskite‐type oxide lanthanoid‐substituted BiCoO3 exhibits a reversible negative thermal expansion (NTE) originated from the coordination change from the CoO5 pyramid to the CoO6 octahedron due to melting of the dxy orbital ordering in the d6 electron configuration, and the 6.1% volume shrinkage in Bi0.82Nd0.18CoO3 is the largest ever observed in the
Yuki Sakai, Kazuki Takahashi, Shogo Wakazaki, Takumi Nishikubo, Jun Miyake, Takehiro Koike, Teppei Nagase, Takafumi Yamamoto, Kano Hatayama, Masaichiro Mizumaki, Masaki Azuma   +10 more
wiley   +1 more source

SUMS OF SQUARES OF LINEAR FORMS

, 2008
. Let k be a real field. We show that every non-negative homogeneous quadratic polynomial f(x1,..., xn) with coefficients in the polynomial ring k[t] is a sum of 2n · τ(k) squares of linear forms, where τ(k) is the supremum of the levels of the finite ...
Jesús M. Ruiz, Claus Scheiderer, José F. Fernando   +2 more
core  

Enhancing Near‐Room‐Temperature Thermoelectric Performance of n‐Type Mg3(Sb, Bi)2‐Based Materials via ZrB2 Heterointerface Engineering

Advanced Science, EarlyView.
A conductive ZrB2 ceramic composite strategy was developed for Mg3(Sb, Bi)2 thermoelectrics to regulate carrier transport and phonon scattering through heterointerface engineering. The 1.0 wt.% ZrB2 composite achieved enhanced room‐temperature performance, with a power factor of 28.51 µW cm−1 K−2 and a peak ZT of 1.22 at 573 K.
Yangyang Xu, Li Zhang, Meng Li, Jie Zhang, Nan‐Hai Li, Yan‐Ling Yang, Xiao‐Lei Shi, Zhi‐Gang Chen   +7 more
wiley   +1 more source

Modular Metamaterials for Adaptable MRI Signal Control: Combining Dipole Array With a New Hexagon‐Based Artificial Dielectrics

Advanced Science, EarlyView.
A flexible, hexagonally packed artificial dielectric providing a wide range of effective permittivities (εr ≈ 30–1400) without lumped elements was developed for clinical and ultra‐high‐field MRI. Combined with modular passive‐dipole arrays, the system enables adaptable RF field shaping through electric‐ and magnetic‐dipole tuning.
Santosh Kumar Maurya, Ilan Goldberg, Rita Schmidt   +2 more
wiley   +1 more source

Emergent Magnetism, Heavy Electrons, and Pressure‐Induced Reentrant Superconductivity in the Iron Substituted 4d Transition‐Metal Sulfides

Advanced Science, EarlyView.
This work illustrates that magnetic Fe substitution enables systematic modulation of physical properties of the putative unconventional superconductor Rh17S15. Iron doping uncovers delicate competition between weak ferromagnetism, spin‐glass states, heavy‐fermion signatures, and superconductivity.
Yalei Huang, Lu Xin, Na Zuo, Bin Li, Wei Zhou, Dhanarajagopal Alltrin, Boning Yu, Haiyang Yang, Bin Qian, Wen‐Chin Lin, Raman Sankar, Michael Smidman, Xiangzhuo Xing, Chunqiang Xu, Xiaobing Liu, Jianhui Dai, Dong Qian, Shiyan Li, Xiaofeng Xu   +18 more
wiley   +1 more source

Internal Resonance Mismatch‐Controlled Dissipative Bistability Collapse in Coupled Micromechanical Oscillators

Advanced Science, EarlyView.
This paper reveals internal resonance mismatch‐controlled dissipative bistability collapse in a coupled micromechanical resonator. Tuning δIR changes both internal‐mode amplitude and phase‐dependent feedback. For negative mismatch, Duffing bistability survives.
Jianlin Chen, Xin Zhou, Takashiro Tsukamoto, Nan Wang, Shuji Tanaka   +4 more
wiley   +1 more source

Quaternion Algebra over Rational Number Field

, 2014
本論文主要不只是探討四元素環在有理數上的分類情況，也描述由他們所形成的Brauer群結構。 有理數上的四元素環大致可分為2乘2矩陣與可除環情況，而我們可以用quadratic form討論其同構狀況。由於2乘2矩陣均同構，故只需考慮可除環的情況，其可更進一步分為不同的同構狀況。 在局部域的情況，可說明其可除環均同構，並使用希爾伯特符號來分類其為2乘2矩陣或是可除環。 最後我們使用Brauer群來描述其分類，並且闡述其群運算方式，透過Hasse ...
Lin, Yun-Xiang, 林運翔
core  

Atomistic Kinetics of Dislocation‐Mediated Grain Growth in Monolayer MoS2

Advanced Science, EarlyView.
Atomic‐resolution in‐situ heating microscopy directly visualizes dislocation‐mediated grain boundary migration and grain growth in monolayer MoS2. Mobile grain boundaries migrate through collective motion of Mo 5|7 dislocations, whereas S 5|7 defects remain largely immobile.
Chang‐Won Choi, Min‐Yeong Choi, Tao Du, Jinho Rhee, Seokho Moon, Yeon‐Seo Nam, Xiaoyan Lu, Jong Kyu Kim, Jungwon Park, Moon‐Ho Jo, Cheol‐Joo Kim, Si‐Young Choi   +11 more
wiley   +1 more source

Twin‐Lever Multifunctional Meta‐Optics With High Longitudinal Tolerance

Advanced Science, EarlyView.
We introduce a single‐layer, CMOS‐compatible metasurface that allows for polarization‐programmable, achromatic broadband dual‐mode imaging with high longitudinal tolerance. The twin‐lever design combines bright‐field focusing and vortex‐based edge‐enhanced imaging while managing axial intensity distribution from 488 to 633 nm.
Isma Javed, Kyungtae Kim, Aqib Raza Shah, Dohyun Kang, Joohoon Kim, Azhar Javed Satti, Xuefeng Liu, Muhammad Zubair, Jichuan Xiong, Muhammad Qasim Mehmood, Junsuk Rho   +10 more
wiley   +1 more source