分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Warm absorbers (WAs) located approximately in the region of $1-1000$ parsecs are common phenomena in many active galactic nuclei (AGNs). The driving mechanism of WAs is still under debate. Ultra-fast outflows (UFOs) which are launched very close to the central black hole are also frequently observed in AGNs. When UFOs move outwards, they will collide with the interstellar medius (ISM) gas. In this paper, we study the possibility that whether WAs can be generated by the interaction between ISM gas and the UFOs. We find that under some ISM gas conditions, WAs can be generated. However, the covering factor of WAs is much smaller than that given by observations. This indicates that other mechanisms should also be at work. We also find that the properties of the WAs mainly depend on the density of the ISM injected into the computational domain from the outer radial boundary (1000 parsec). The higher the density of the ISM is, the higher the mass flux and kinetic power of the WAs will be. The kinetic power of the UFO driven WAs is much less than $1\%$ of the bolometric luminosity of its host AGNs. Therefore, the UFO driven WAs might not contribute sufficient feedback to its host galaxy.
分类： 心理学 >> 认知心理学 提交时间： 2020-06-17
摘要： This study aimed to examine the brain mechanisms underlying the distinctions between automatic and controlled handwriting. Functional magnetic resonance imaging data were collected while adult participants (n = 53) performed a copying task with varying speed control demands. Network analysis showed significant differences in functional connectivity within and between the frontoparietal network (FPN), the default mode network (DMN), the dorsal attention network (DAN), the somatomotor network (SMN) and the visual network (VN) between automatic and speed-controlled handwriting irrespective of written materials, which are thought to reflect general executive control and task-relevant visuomotor operations. However, there were no differences in brain activation between automatic and controlled handwriting. These results suggest that reconfiguration of functional network architecture, rather than regional activation, underlies the dissociations between automatic and controlled handwriting. Our findings shed new light on the neural mechanisms of handwriting mastery and handwriting impairments in individuals with neurological disorders.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： One of the most prominent problems of optical/ultraviolet (UV) tidal disruption events (TDEs) is the origin of their optical/UV emission. It has been proposed that the soft X-rays produced by the stellar debris accretion disk can be reprocessed into optical/UV photons by a surrounding optically thick envelope or outflow. However, there is still no detailed models for this mechanism. In this paper, by performing hydrodynamic simulations with radiative transfer, we calculate the optical/UV emission of the circularized stellar debris accretion flow/outflow system. We find that the optical/UV photons can be generated by reprocessing the emission of the accretion flow in the optically thick outflows. The model can well interpret the observed emission properties of optical/UV TDEs, including the emission radius, the radiation temperature and the luminosity, as well as the evolution of these quantities with time, providing a strong theoretical basis for understanding the origin of optical/UV TDEs.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Winds play a significant role in active galactic nuclei feedback process. Previous simulations studying winds only focus on a small dynamical range. Therefore, it is unknown how far the winds can go and what the properties of the winds will be if they can move to large radii. We perform simulations to study the large scale dynamics of winds driven by line force. We find that the properties of the winds depend on both black hole mass ($M_{BH}$) and accretion disk luminosity. When the accretion disk luminosity is $0.6L_{edd}$ ($L_{edd}$ being Eddington luminosity), independent of $M_{BH}$, the winds have kinetic energy flux exceeding $1\% L_{edd}$ and can escape from the black hole potential. For the case with the accretion disk luminosity equaling 0.3$L_{edd}$, the strength of the winds decreases with the decrease of $M_{BH}$. If $M_{BH}$ decreases from $10^9$ to $10^6$ solar mass ($M_\odot$), the winds kinetic energy flux decreases from $\sim 0.01 L_{edd}$ to $ \sim 10^{-6} L_{edd}$. In case of $M_{BH}\geq 10^7 M_\odot$, winds can escape from black hole potential. In the case of $M_{BH}=10^6 M_\odot$, the winds can not escape. We find that for the ultra-fast winds observed in hard X-ray bands (\citealt{Gofford et al. 2015}), the observed dependence of the mass flux and the kinetic energy flux on accretion disk luminosity can be well produced by line force driven winds model. We also find that the properties of the ultra-fast winds observed in soft X-ray bands can be explained by the line force driven winds model.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： The sensitivity of perturbation sensing can be effectively enhanced with higher-order exceptional points due to the nonlinear response to frequency splitting. However, the experimental implementation is challenging since all the parameters need to be precisely prepared. The emergence of exceptional surface (ES) improves the robustness of the system to the external environment, while maintaining the same sensitivity. Here, we propose the first scalable protocol for realizing photonic high-order exceptional surface with passive resonators. By adding one or more additional passive resonators in the low-order ES photonic system, the 3- or arbitrary N-order ES is constructed and proved to be easily realized in experiment. We show that the sensitivity is enhanced and experimental demonstration is more resilent against the fabrication errors. The additional phase-modulation effect is also investigated.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Polarization beam splitter (PBS) is a crucial photonic element to separately extract transverse-electric (TE) and transverse-magnetic (TM) polarizations from the propagating light fields. Here, we propose a concise, continuously tunable and all-optical partial PBS in the vector optomechanical system which contains two orthogonal polarized cavity modes with degenerate frequency. The results show that one can manipulate the polarization states of different output fields by tuning the polarization angle of the pumping field and the system function as partial PBS when the pump laser polarizes vertically or horizontally. As a significant application of the tunable PBS, we propose a scheme of implementing quantum walks in resonator arrays without the aid of other auxiliary systems. Furthermore, we investigate the optomechanically induced Faraday effect in the vector optomechanical system which enables arbitrary tailoring of the input lights and the behaviors of polarization angles of the output fields in the under couple, critical couple, and over couple regimes. Our findings prove the optomechanical system is a potential platform to manipulate the polarization states in multimode resonators and boost the process of applications related to polarization modulation.
分类： 医学、药学 >> 药学 提交时间： 2022-12-26
Chen-yu Wang
Di-hong Yang
Xiao-min Niu
Lu Han
Wen Wang
Roman Filimonov
Sajid Ali Shah
Xin-yang Weng
Zheng Jiao
摘要： 目的：在非小细胞肺癌患者中，免疫检查点抑制剂联合化疗方案比传统化疗方案为患者提供了更多获益。然而，依然有部分患者无法得到获益，存在着免疫耐受的现象。临床可测量的生物标志物是预测临床结果和优化剂量策略所必需的。本研究旨在通过定量系统药理学（QSP）研究可获得的生物标志物，这些生物标志物可以预测非小细胞肺癌患者的临床结果，并优化atezolizumab和nab紫杉醇联合治疗的给药策略。 方法：使用MATLAB中的SimBiology工具箱，基于已发表的三阴性乳腺癌QSP模型开发该模型。利用该模型，我们生成了一个虚拟患者队列以进行虚拟临床试验模拟，并使用来自真实临床试验（IMpower131）的数据进行模型校准和验证。 结果：最终QSP模型预测与临床报告的疗效终点一致。患者的肿瘤中基线CD8+和CD4+T细胞密度与临床获益显著相关。Roc分析进一步揭示了它们作为联合治疗方案的预测生物标志物的潜力。虚拟临床试验模拟显示，将nab紫杉醇剂量从100 mg/m2降至75 mg/m2将导致ORR降低，但依然高于atezolizumab单药治疗。三种atezolizumab给药策略联合nab紫杉醇显示出相似的疗效。 结论：本研究提供了一个QSP模型，可用于生成虚拟患者队列并进行虚拟临床试验。我们的研究结果证明了它在预测免疫疗法和化疗的疗效、识别预测性生物标志物以及指导未来临床试验设计方面的潜力。
分类： 光学 >> 量子光学 提交时间： 2023-02-22
Jin Chuan Zhang
Hong Yang Zhu
Xiao Mei Zhu
Yan Li Zhang
Zhao Wang
Fei Liang Chen
Ke Li
Xiao Feng Li
Wei Li Zhang
摘要： Whispering gallery mode (WGM) microcavities can efficiently store and manipulate light with strong light confinement and long photon lifetime, while coupling light into and from WGMs is intrinsically hindered by their unique feature of rotational symmetry. Here, a scattering-assisted liquid crystal (LC) micropillar WGM laser is proposed. WGM lasing at the surface of the micropillar is obviously enhanced by fluorescence scattering in the core of the micropillar. Besides, weak scattering of LC molecules also builds efficient coupling channels between the laser modes and the axial transmission modes of the micropillar-based waveguide, providing an all-in-one liquid WGM laser with functions of self-seeding and self-guiding. Furthermore, based on the hysteresis characteristics of the electrically anchored LC molecules under the interaction of thermal force, an erasable read-write liquid memory device is proposed, paving the way for the application of logic-controllable WGM lasers in optical storage and optical control.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Xuan Mao
Hong Yang
Dan Long
Min Wang
Peng-Yu Wen
Yun-Qi Hu
Bo-Yang Wang
Gui-Qin Li
Jian-Cun Gao
Gui-Lu Long
摘要： The highly efficient coupling of light from conventional optical components to optical mode volumes lies in the heart of chip-based micro-devices, which is determined by the phase-matching between propagation constants of fiber taper and the whispering-gallery-mode (WGM) of the resonator. Optical gyroscopes, typically realized as fiber-optic gyroscopes and ring-laser gyroscopes, have been the mainstay in diverse applications such as positioning and inertial sensing. Here, the phase-matching is theoretically analyzed and experimentally verified. We observe Sagnac effect in a millimeter-scale wedged resonator gyroscope which has attracted considerable attention and been rapidly promoted in recent years. We demonstrate a bidirectional pump and probe scheme, which directly measures the frequency beat caused by the Sagnac effect. We establish the linear response between the detected beat frequency and the rotation velocity. The clockwise and counterclockwise rotation can also be distinguished according to the value of the frequency beat. The experimental results verify the feasibility of developing gyroscope in WGM resonator system and pave the way for future development.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Rui-Tao Wang
Hong-Yang Li
Lu Feng
Min Li
Qi Bian
Jun-Wei Zuo
Kai Jin
Chen Wang
Yue Liang
Ming Wang
Jun-Feng Dou
Ding-Wen Zhang
Kai Wei
You-Ming Guo
Yong Bo
Sui-Jian Xue
摘要： The application of sodium laser guide star is the key difference between modern adaptive optics system and traditional adaptive optics system. Especially in system like multi-conjugate adaptive optics, sodium laser guide star asterism which is formed by several laser guide stars in certain pattern is required to probe more atmospheric turbulence in different directions. To achieve this, a sodium laser guide star asterism launching platform is required. In this paper, we will introduce the sodium laser guide star asterism launching platform built and tested on the 1.8m telescope of the Gaomeigu Observatory. The platform has two functions: one is to compare the performance of sodium laser guide stars generated by different lasers at the same place; the other is to generate sodium laser guide star asterism with adjustable shape. The field test results at the beginning of 2021 verify the important role of the platform, which is also the first time to realize sodium laser guide star asterism in China.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Rui-Tao Wang
Hong-Yang Li
Lu Feng
Min Li
Qi Bian
Jun-Wei Zuo
Kai Jin
Chen Wang
Yue Liang
Ming Wang
Jun-Feng Dou
Ding-Wen Zhang
Kai Wei
You-Ming Guo
Yong Bo
Sui-Jian Xue
摘要： The application of sodium laser guide star is the key difference between modern adaptive optics system and traditional adaptive optics system. Especially in system like multi-conjugate adaptive optics, sodium laser guide star asterism which is formed by several laser guide stars in certain pattern is required to probe more atmospheric turbulence in different directions. To achieve this, a sodium laser guide star asterism launching platform is required. In this paper, we will introduce the sodium laser guide star asterism launching platform built and tested on the 1.8m telescope of the Gaomeigu Observatory. The platform has two functions: one is to compare the performance of sodium laser guide stars generated by different lasers at the same place; the other is to generate sodium laser guide star asterism with adjustable shape. The field test results at the beginning of 2021 verify the important role of the platform, which is also the first time to realize sodium laser guide star asterism in China.
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