一种解决光刀断线问题的新方法

用光切法测量物体的三维形貌 ,由于其原理简单、速度快、精度高等特点 ,所以得以广泛应用。针对光切法中一直存在的光刀断线问题进行了讨论 ,并提出采用自适应阈值的光刀中心提取法与一维、二维光刀数据修补技术相结合来解决此问题 ,可同时消除噪声的影响。实验证明 :采用此方法可以取得很好的效果。     

再谈“PT对称的非厄米体系的能谱性质”

本文详细讨论了具有PT对称的一维量子系统虚数势对能谱的影响,补充了《大学物理》2018年第3期《PT对称的非厄米体系的能谱性质》一文在系统维度为奇数情况下的结论.     

Effects of flexibility on liquid crystalline polymer behavior: The nematic broken rod

A new theory for liquid crystalline polymers is developed, and its behavior in simple shear flow is analyzed. The theory accounts for molecular flexibility by employing a microstructure consisting of two rigid rods linked by a joint with a tunable stiffness. The probability distribution function equation for the orientation of the arms of the broken rod is derived. The adaptation of the smoothed particle hydrodynamics (SPH) technique for obtaining numerical solutions to this theory is detailed. The behavior of the theory at equilibrium is derived analytically and compared with numerical results; the SPH technique is then used to obtain results in flow. It is found that in the limit of a nearly stiff joint, the model gives behavior that is very similar to that of rigid rod polymers, the only difference being a lesser tendency to tumble due to greater variation in the order parameter. For nearly free joints, the shear flow induces interesting dynamics for the transition between states with the arms outstretched and those where they are folded up (so‐called “hairpins” of main‐chain LCPs). © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 281–300, 1999     

有界Heyting代数的扩张模糊LI-理想

运用代数学与模糊集的基本原理和运算方法深入研究有界Heyting代数的扩张模糊LI-理想理论。在有界Heyting代数H,≤,→,0,1中,引入了模糊LI-理想f关于H上的模糊子集κ的扩张模糊LI-理想和不变模糊LI-理想概念,给出了扩张模糊LI-理想和不变模糊LI-理想的若干重要性质和等价刻画;讨论了扩张模糊LI-理想与生成模糊LI-理想之间的关系;考查了扩张模糊LI-理想在构造格结构研究中的应用,证明了有界Heyting代数H,≤,→,0,1的模糊LI-理想全体之集FLIH的三类子集在模糊集合包含序?下均构成完备Heyting代数。     

Colorings versus list colorings of uniform hypergraphs

Let $r$ be an integer with $r\ge 2$ and $G$ be a connected $r$-uniform hypergraph with $m$ edges. By refining the broken cycle theorem for hypergraphs, we show that if $k>\text{◂/▸}\frac{m-1}{\ln (1+\sqrt{2})}\approx \text{◂⋅▸}1.135\left(m-1\right)$, then the $k$-list assignment of $G$ admitting the fewest colorings is the constant list assignment. This extends the previous results of Donner, Thomassen, and the current authors for graphs.     

Extended-source broken gate tunnel FET for improving direct current and analog/radio-frequency performance

The various advantages of extended-source(ES), broken gate(BG), and hetero-gate-dielectric(HGD) technology are blended together for the proposed tunnel field-effect transistor(ESBG TFET) in order to enhance the direct-current and analog/radio-frequency performance. The source of the ESBG TFET is extended into channel for the purpose of increasing the point and line tunneling in the device at the tunneling junction, and then, the on-state current for the ESBG TFET increases. The influence of the source region length on the direct-current and radio-frequency performance parameters of the ESBG TFET is analyzed in detail. The results show that the proposed TFET exhibits a high on-state current to off-state current ratio of 1013, large transconductance of 1200 μS/μm, high cut-off frequency of 72.8 GHz, and high gain bandwidth product of 14.3 GHz. Apart from these parameters, the ESBG TFET also demonstrates high linearity distortion parameters in terms of the second-and third-order voltage intercept points, the third-order input interception point, and the third-order intermodulation distortion. Therefore, the ESBG TFET greatly promotes the application potential of conventional TFETs.     

Stochastic radiative transfer in multilayer broken clouds. Part II: validation tests

In the second part of our two-part paper, we estimated the accuracy and robustness of the approximated equations for the mean radiance that were derived in Part I. In our analysis we used the three-dimensional (3D) cloud fields provided by (i) the stochastic Boolean model, (ii) large-eddy simulation model and (iii) satellite cloud retrieval. The accuracy of the obtained equations was evaluated by comparing the ensemble-averaged radiative properties that were obtained by the numerical averaging method (reference) and the analytical averaging method (approximation). The robustness of these equations was estimated by comparing the domain-averaged radiative properties obtained by using (i) the full 3D cloud structure (reference) and (ii) the bulk cloud statistics (approximation). It was shown that the approximated equations could provide reasonable accuracy (∼15%) for both the ensemble- and domain-averaged radiative properties.     

大学普通物理实验的简化、深化和拓展探讨

在分析大学普通物理实验改革“深化”和“简化”两种流行观点的基础上,针对当前大学普通物理实验存在的主要问题,综合利用简化、深化和拓展等手段,从设立大学普通物理单元实验,改进大学普通物理实验内涵,在大学普通物理实验中完善计算机辅助功能等方面进行了有价值的探讨.     

Role of electronic nematicity in the interplay between s- and d-wave broken-symmetry states

To understand the role of electronic nematic order in the interplay between s- and d-wave particle-particle or particle-hole condensate states, relations between various s- and d-wave order parameters are studied. We find that the nematic operator transforms two independent six-dimensional vectors. The d-wave superconducting, d-density wave, and antiferromagnetic orders are organized into one vector, and the s-wave superconducting, charge density wave, and spin-triplet d-density wave orders into the other vector. Each vector acts as a superspin and transforms under the action of SO(6) where charge, spin, η- and π-pairing, spin-triplet nematic operators satisfy the SO(6) Lie algebra. Electronic nematic order is not a part of the SO(6) group. It commutes with all 15 generators. Our findings imply that nematic order does not affect the competition among the order parameters within the same superspin, while it strongly interferes the interplay between two order parameters that belong to different superspins. For example, nematicity allows a linear coupling between d- and s-wave superconducting order parameters which modifies the superconducting transition temperature. A generalized Ginzburg-Landau theory and further physical implications are discussed.