振荡吸积盘的光变研究

理论研究指出随机振荡吸积盘可能引起活动天体的光变,然而观测数据分析表明光变中除了含有随机噪声外还存在混沌因素.将混沌因素引入到随机振荡吸积盘中,构成"混沌+随机"振荡吸积盘模型.通过分析扰动的相图,直观再现了混沌吸引子的状态.研究结果表明:在随机因素占主导时,光变混乱无序;随机因素与混沌因素相当时,光变上下起伏类似于心电图;混沌因素占主导时,光变具有一定有序性.模拟光变曲线的关联维与观测数据的关联维一致,表明模拟光变曲线与观测结果之间存在内在联系.     

高效液相色谱法测定红茶中的茶黄素

建立了一种用于分析红茶中茶黄素的高效液相色谱法。该方法采用反相C18柱;流动相A为2%醋酸,流动相B为乙腈-乙酸乙酯(体积比为21∶3),梯度洗脱,流速0.8 mL/min;紫外检测波长280 nm;柱温40 ℃;外标法定量。结果表明,所采用的标准曲线有良好的线性关系(r=0.9990~0.9992),加标回收率为96.88%~103.57%,方法的精密度良好(平均RSD<1.5%)。该方法简便、快速、准确,可用于实际样品的测定。     

Intramolecular vibrational dynamical barrier due to extremely irrational couplings

The intramolecular vibrational dynamics due to extremely irrational couplings is demonstrated by contrast to the resonance couplings, for the three-mode case of H分子物理学 分子内振动弛豫 甚高频无理耦合 共鸣 振动动力学intramolecular vibrational relaxation, extremely irrational couplings, resonanceProject supported by the National Natural Science Foundation of China (Grant No~20373030) and the Foundation for Key Program of Ministry of Education, China (Grant No~306020) and the Specialized Research Fund for the Doctoral Program of Higher Educatio2007-03-04The intramolecular vibrational dynamics due to extremely irrational couplings is demonstrated by contrast to the resonance couplings, for the three-mode case of H2O as an example. The extremely irrational couplings are shown to impose such strong hindrance to intramolecular vibrational relaxation （IVR） that they act as barriers. They restrict the direct action/energy transfer between the two stretching modes, though they allow the transfer between a stretching and a bending modes. In contrast, the resonance is more mediated by the bending mode and leads to chaotic IVR. It is also shown that there is a region in the dynamical space in which resonance and extremely irrational couplings coexist.     

SIM/GC/ITD测定土样中ppt级多氯二苯并二噁英

本文介绍了以选择离子检测方式的气相色谱-离子阱检测器(SIM/GC/ITD)分析土样中ppt级多氯二苯并-对-二噁英的方法。该法所用仪器简单,操作简便,净化效率和回收率高。当组分浓度在ppt～ppb范围、母体组成在很大范围变动时,也有较好的重复性。     

Shielding effects in fusion reactions with a proton-halo nucleus

To explain the experimental observation that the fusion cross-section of a proton-halo nucleus with a heavy target nucleus is not enhanced as expected,the shielding hypothesis was proposed,where the proton-halo nucleus is polarized and the valence proton shielded by the core.In the frame of the improved quantum molecular dynamics model,the fusion reaction 17F on 208Pb around the Coulomb barrier is simulated.The existence of the shielding effect is verified by the microscopic dynamics simulations.Its influence on the effective interaction potential is also investigated.     

硅微机械FP腔器件机电特性模拟

介绍了一种硅微机械FP腔器件,该器件作为光学滤波器、光学衰减器等在光纤通信技术中具有广泛应用.采用化学气相沉积、刻蚀、金属蒸发等工艺对该器件进行加工,并利用湿法腐蚀释放使其形成悬空结构,悬空膜采用静电激励驱动.分析了器件的基本原理、工作范围、静电激励的阈值电压等特性,并指出了影响阈值电压大小的因素.     

A Low Sampling Rate Receiver Design for Multi-Antenna Multi-User OFDM Systems

The future 6G mobile communication network will support an unprecedented amount of Internet of Things (IoT) devices, which will boost the demand for low cost terminals under the principle of green communication. One of the critical issues for low cost terminals is the sampling rate of analog-to-digital converters (ADCs) at the receivers. A high sampling rate of the ADC gives rise to a high energy consumption and high hardware cost for the terminal. In the conventional multi-user OFDM systems, all users have to sample the received signal with a sampling rate that is larger than or equal to the Nyquist rate, despite only a small fraction of the bandwidth (number of subcarriers) is allocated to each user. This paper proposes a low sampling rate receiver design for multi-antenna multi-user OFDM systems. With the aid of zero-forcing precoding, the sampling rate of the receiver can be reduced to 1/K of the Nyquist rate, where K is the number of users. The simulation results show that with a significant reduction in sampling rate, performance loss is insignificant and acceptable in terms of bit error rate, mutual information and peak-to-average power ratio.     

Institution Publication Feature Analysis Based on Time-Series Clustering

Based on the time series of articles obtained from the literature, we propose three analysis methods to deeply examine the characteristics of these articles. This method can be used to analyze the construction and development of various disciplines in institutions, and to explore the features of the publications in important periodicals in the disciplines. By defining the concepts and methods relevant to research and discipline innovation, we propose three methods for analyzing the characteristics of agency publications: numerical distribution, trend, and correlation network analyses. The time series of the issuance of articles in 30 important journals in the field of management sciences were taken, and the new analysis methods were used to discover some valuable results. The results showed that by using the proposed methods to analyze the characteristics of institution publications, not only did we find similar levels of discipline development or similar trends in institutions, achieving a more reasonable division of the academic levels, but we also determined the preferences of the journals selected by the institutions, which provides a reference for subject construction and development.