基于瑞利分布的大型风电场风机维护方案优化

针对大型风电场风能利用率低下的问题,从优化风机维护方案的角度出发,在假设风速服从瑞利分布的前提下,建立了两阶段多目标0-1规划模型,确定了所有风机每年2次的维护方案,方案以风电场风能利用率最大为目标,兼顾了维修人员的值班任务和维护任务的均衡,具有操作简单、可行性强的优势.     

基于相干光码分多址技术的隐藏通信系统仿真

提出了光域隐藏通信的概念以及评价其性能的指标:隐藏性、可用性和稳健性,给出了基于现有光纤通信体制的三种光域隐藏通信方案及其对系统配置的要求.使用光纤通信系统仿真软件对所提出的方案进行了仿真研究,针对现有的光纤宿主信道的特点,提出了采用码移键控(CSK)平衡调制方式和基于等效相移超结构光纤光栅(EPS-SSFBG)双边带编/解码器的系统配置方案以提高系统的性能.结果表明,该方法各项性能指标良好.在信噪比为-13 dB,信号完全隐藏在信道噪声中的情况下,仍然能够以1.25 Gb/s的速率保持通信,能够抑制隐藏系统与宿主系统间的相互影响,是一种具有较高应用价值的光域隐藏通信方法.     

Various Trap States at SiGe-SiO2 Interface Formed by a Pulsed Laser

We report fabrication of low-dimensional structures in air by a pulsed laser on SiGe alloy samples in which different oxide structures are formed by laser irradiation and annealing treatment. The micro-structures on SiGe are more complex than those on Si. A series of photolumineseence （PL） emission is observed due to various trap states at the SiGe-SiO2 interface formed under different preparing conditions. The peak centre of PL emission exhibits red=shift from Si to SiGe because of narrower gap. A model for explaining the PL emission is proposed in which the trap states of the interface between some oxide and SiGe play an important role.     

Nonplanar Ion-Acoustic Solitons in Electron-Positron-Ion Quantum Plasmas

The propagation of nonplanar quantum ion-acoustic solitary waves in a dense, unmagnetized electron-positronion （e-p-i） plasma are studied by using the Korteweg-de Vries （KdV） model. The quantum hydrodynamic （QHD） equations are used taking into account the quantum diffraction and quantum statistics corrections. The analytical and numerical solutions of KdV equation reveal that the nonplanar ion-acoustic solitons arc modified significantly with quantum corrections and positron concentration, and behave differently in different geometries.     

Novel Quantum Secret Sharing and Controlled Communication Schemes Based on Einstein-Podolsky-Rosen Correlations

Employing quantum registers, we first proposed a novel （2, 3） quantum threshold scheme based on Einstein- Podolsky Rosen （EPR） correlations in this letter. Motivated by the present threshold scheme, we also propose a controlled communication scheme to transmit the secret message with a controller. In the communication protocol, the encoded quantum message carried by particles sequence, is transmitted by legitimate communicators.     

侧面抽运板状激光介质的热汇冷却

高热负荷固体激光介质的热效应已经成为制约激光器功率进一步提高的严重障碍,只有对激光介质进行有效的冷却才能保证其安全运行。以不均匀换热系数模型为基础,研究了具有非均匀内热源的侧面双向抽运板状激光介质在狭窄通道强制对流冷却情况下的耦合换热问题,对热汇冷却方案下介质的温度分布和热应力分布进行了数值模拟和分析,并对复合介质、蓝宝石和金刚石三种热汇材料进行对比。结果表明,忽视换热系数的非均匀性将导致应力计算结果偏低。对于侧面抽运、侧面冷却的激光介质,金刚石热汇冷却方案最佳,蓝宝石热汇方案次之,而复合介质方案不宜采用。     

算思结合 突破困难 提升素养——以一道解析几何题求解历程为例

日前笔者所在学校高三的一次月考结束后,很多学生都觉得自己考“爆”了.原来是试卷中涉及解析几何的解答题没能处理好,耽误了时间,影响了学生的考试状态,导致整份试卷没有做好.很多时候遇到解析几何问题,一部分学生纠结的是明明知道选择的处理方法可能不是最佳方案,但理论上“应该”能解决问题,却苦于繁琐的运算而纷纷止步,导致解析几何题不能彻底解决;还有一部分学生总想回避繁琐的计算、找捷径,一旦考场上找不到更好的方案便失去信心,加之平时运算训练不到位,在繁杂的运算面前便无从下手,只能望运算而兴叹,最终以失败而告终.     

物理学中的“场”和“理想模型”

一物理学中＂场＂的概念桌子、黑板、房、树木……都是由分子、原子组成的,而分子、原子又是由电子、质子、中子等基本粒子组成的.这些实物都是物质.物质是客观存在的,能作用于我们的感觉器官而引起感觉的东西.在我们周围的物质世界里,     

在时域实验研究扩散诱导的Ramsey压窄

基于Duan-Lukin-Cirac-Zoller(DLCZ)方案,在时域上研究了扩散诱导的Ramsey压窄. 以⁸⁷Rb热原子系综为研究对象,观测到缓冲气体,激光束尺寸和镀石蜡Rb池均可以导致Ramsey压窄现象. 实验结果和文献中重复相互作用模型预期的一致.     

Scalable Arbitrated Quantum Signature of Classical Messages with Multi-Signers

Unconditionally secure signature is an important part of quantum cryptography. Usually, a signature scheme only provides an environment for a single signer. Nevertheless, in real applications, many signers may collaboratively send a message to the verifier and convince the verifier that the message is actually transmitted by them. In this paper, we give a scalable arbitrated signature protocol of classical proved to be secure even with a compromised arbitrator. messages with multi-signers. Its security is analyzed and proved to be secure even with a compromised arbitrator.