搜索结果: 1-15 共查到“理学 fields”相关记录503条 . 查询时间(0.171 秒)
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Occupation fields for Markov loops
马尔可夫循环 占用域 格林函数
2023/11/29
In this talk, we introduce occupation fields for vertices and oriented edges and compute their distributions. More precisely, under the Markov loop measure, the expected number for crossings of an ori...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Positivity and model complete fields
正性 模型完备域 有理数域
2023/11/13
In recent work with Will Johnson, we have shown that given a curve C over the rational number field Q with genus at least 2 and C(Q) is empty, the class of fields K of characteristic 0 such that C(K) ...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Characterizations of Separably Differentially Closed Fields
可分 微分闭域 微分场
2023/11/7
In this talk, we define a new class of differential fields called separably differentially closed fields and show their several characterizations by comparing them with differentially closed fields of...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Fields with a generic multiplicative endomorphism
通用乘法 自同态 域
2023/5/4
The theory of fields expanded by a unary function symbol for a multiplicative endomorphism admits a model-companion, we denote it ACFH. It is a new example of an NSOP1 theory which is not simple. I wi...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Rational points and homogeneous spaces over function fields of curves
曲线函数场 有理点 齐次空间
2023/4/17
In the last decade, there has been a growing interest in the study of rational points on homogeneous spaces of linear algebraic groups defined over fields having good arithmetical properties other tha...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Numerical method for low-frequency electromagnetic fields and its applications
低频 电磁场数值 低频涡流场 有限元编程
2023/4/13
本报告首先回顾传统低频涡流场的两种计算格式，指出有限元编程实现过程中的基函数选择以及需要注意的难点问题。第二部分针对静磁场问题，通过引入规范条件提出了一种基于矢量磁位和磁场强度的新型的对偶格式，该方法通过巧妙构造基于矢量磁位和磁场强度的计算格式，整体矩阵完全一致并且可以给出系统电感参数的上下界，在实际参数提取中有很好的应用前景。在第三部分，由于传统低频涡流场近似不能有效考虑分布电容效应，而传统高频...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Zeros of complete symmetric polynomials over finite fields
有限域 完全对称 多项式 零点
2023/4/13
Wan and Zhang have recently obtained a nontrivial lower bound for the number of zeros of complete symmetric polynomials over finite fields, and proposed a problem whether their bound can be improved. ...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Number of rational points of difference varieties in finite difference fields
有限差分域 差分簇 有理点数
2023/4/13
A difference field is a field with a distinguished automorphism. Automorphisms of a finite field are powers of the Frobenius map. In this talk, I will discuss how to estimate the number of rational po...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Conformally invariant fields out of Brownian loop soups
布朗环汤 共形 不变场 布朗分布
2023/4/14
For each central charge c\in (0,1], we construct a conformally invariant field which is a measurable function of the local time field \mathcal{L} of the Brownian loop soup with intensity c and i.i.d. ...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：Microphysical and non-thermal processes in the circumgalactic medium: turbulence, magnetic fields and cosmic rays
银河系 周介质 微物理 非热过程 湍流 磁场 宇宙射线
2023/4/18
Multiphase gas structure is ubiquitous in our universe. Recent observations suggest that large quantities of cool (10^4 K) gas are detected in the circumgalactic medium (CGM) of galaxy halos, which ex...
Academy of Mathematics and Systems Science, CAS Colloquia & Seminars：RL-based Trajectory Planning for Efficient Exploration of Spatio-Temporal Fields
RL 高效时空场 探测轨迹 规划
2023/5/17
This talk concerns trajectory planning problems of an autonomous vehicle for field exploration, where the vehicle needs to accumulate sufficient information on a spatio-temporal field and to reach a d...
Physicists steer chemical reactions by magnetic fields and quantum interference（图）
磁场 量子干涉 化学反应 量子力学 超冷化学
2023/6/9
Physicists in the MIT-Harvard Center for Ultracold Atoms (CUA) have developed a new approach to control the outcome of chemical reactions. This is traditionally done using temperature and chemical cat...
Scientists image magnetic fields at edge of M87's black hole（图）
Scientists mage magnetic fields edge M87 black hole
2021/3/26
Event Horizon Telescope scientists, who produced the first image of a black hole, have revealed a new view of the massive object at the center of the M87 galaxy, showing how it looks in polarized...
Researchers develop ultra-sensitive device for detecting magnetic fields（图）
Researchers develop ultra-sensitive device detecting magnetic fields
2020/6/19
A team of Brown University physicists has developed a new type of compact, ultra-sensitive magnetometer. The new device could be useful in applications involving weak magnetic fields, the re...
Scientists deepen understanding of magnetic fields that surround Earth（图）
Scientists magnetic fields surround Earth
2019/10/23
Vast rings of electrically charged particles encircle the Earth and other planets. Now, a team of scientists has conducted research into waves that travel through this magnetic, electrically charged e...