摘要：
针对目前有线全双工通信系统中保密通信技术尚未成熟,在保密性能存在局限性,以同频同时全双工(co-frequency co-time full duplex,CCFD)系统的自干扰(self-interference,SI...展开更多 针对目前有线全双工通信系统中保密通信技术尚未成熟,在保密性能存在局限性,以同频同时全双工(co-frequency co-time full duplex,CCFD)系统的自干扰(self-interference,SI)消除理论为基础,提出一种物理层绝对安全的有线保密通信系统设计方案,通过巧妙地在接收端向链路中释放同时同频大功率人造噪声的方式将目标信号隐藏起来,再利用接收机对噪声信号的已知性,借助CCFD系统的模拟域自干扰消除技术在接收机中实现高dB的SI消除,实现Wyner意义上的绝对安全的保密通信。依据香农理论分析了延迟时间差、窃听位置、传输线长度等因素对SI消除能力和系统安全容量的影响。结果表明:系统的安全容量始终大于零,达到绝对保密通信效果。收起
期刊：
EUROPEAN PHYSICAL JOURNAL C,2023年83(7):1-14 ISSN：1434-6044
通讯作者：
Pang, LG
作者机构：
[Pang, Long-Gang; Wang, Xin-Nian; Yang, Zhong] Cent China Normal Univ, Inst Particle Phys, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;[He, Yayun] South China Normal Univ, Inst Quantum Matter, Guangdong Prov Key Lab Nucl Sci, Guangzhou 510006, Peoples R China.;[He, Yayun] South China Normal Univ, Southern Nucl Sci Comp Ctr, Guangdong Hong Kong Joint Lab Quantum Matter, Guangzhou 510006, Guangdong, Peoples R China.;[Chen, Wei] Wuhan Univ Sci & Technol, Coll Sci, Wuhan 430065, Peoples R China.;[Ke, Wei-Yao; Wang, Xin-Nian] Univ Calif Berkeley, Phys Dept, Berkeley, CA 94720 USA.
通讯机构：
[Pang, LG ] C;Cent China Normal Univ, Inst Particle Phys, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.
摘要：
Mach cones are expected to form in the expanding quark-gluon plasma (QGP) when energetic quarks and gluons traverse the hot medium at a velocity faster than the speed of sound in high-energy heavy-ion collisions. The shape of the Mach cone and the associated diffusion wake are sensitive to the initial jet production location and the propagation direction of the parton shower relative to the radial flow because of the distortion caused by the collective expansion of the QGP and the large density gradient. The shape of jet-induced Mach cones and their distortions in heavy-ion collisions provide a unique and direct probe of the dynamical evolution and the equation of state of QGP. However, it is difficult to identify the Mach cone and the diffusion wake in current experimental measurements of final hadron distributions because they are averaged over all possible initial jet production locations and parton-shower propagation directions. To overcome this difficulty, we develop a deep learning assisted jet tomography which uses the full information of the final hadrons from jets to localize the initial jet production positions. This method can help to constrain the initial regions of jet production in heavy-ion collisions and enable a differential study of Mach-cones with different path lengths and orientations relative to the radial flow of the QGP in heavy-ion collisions.
期刊：
Physica A-Statistical Mechanics and its Applications,2023年617:128666 ISSN：0378-4371
通讯作者：
Liu, FY
作者机构：
[Yang, Chunbin; Liu, Feiyi; Chen, Shiyang; Deng, Weibing; Li, Wei; Chen, Xiangna; Liu, FY] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;[Yang, Chunbin; Liu, Feiyi; Chen, Shiyang; Deng, Weibing; Li, Wei; Chen, Xiangna; Liu, FY] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;[Liu, Feiyi; Papp, Gabor; Liu, FY] Eotvos Lorand Univ, Inst Phys, 1-A Pazmany P Setany, H-1117 Budapest, Hungary.;[Li, Wei] Max Planck Inst Math Sci, D-04103 Leipzig, Germany.;[Shen, Jianmin] Baoshan Univ, Sch Engn & Technol, Baoshan 678000, Peoples R China.
通讯机构：
[Liu, FY ] C;Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Eotvos Lorand Univ, Inst Phys, 1-A Pazmany P Setany, H-1117 Budapest, Hungary.
摘要：
A transfer learning method, Domain Adversarial Neural Network (DANN), is introduced to study the phase transition of two-dimensional q-state Potts model. With the DANN, we only need to choose a few labeled configurations automatically as input data, then the critical points can be obtained after training the algorithm. By an additional iterative process, the critical points can be captured to comparable accuracy to Monte Carlo simulations as we demonstrate it for q = 3,4, 5, 7 and 10. The type of phase transition (first or second-order) is also determined at the same time. Meanwhile, for the second -order phase transition at q = 3, we can calculate the critical exponent & nu; by data collapse. Furthermore, compared to the traditional supervised learning, we found the DANN to be more accurate with lower cost.& COPY; 2023 Elsevier B.V. All rights reserved.
期刊：
Sensors and Actuators B-Chemical,2023年381:133429 ISSN：0925-4005
通讯作者：
Yan Wang
作者机构：
[Ma, Weijia; Wang, Yan] Hubei Minzu Univ, Sch Chem & Environm Engn, Enshi 445000, Peoples R China.;[Fu, Yuheng] Wuhan Univ Technol, Sch Mat Sci & Engn, Wuhan 430070, Peoples R China.;[Tan, Jianfeng; Meng, Gaoxiang] Hubei Minzu Univ, Key Lab Green Mfg Superlight Elastomer Mat State E, Enshi 445000, Peoples R China.;[Tan, Jianfeng; Meng, Gaoxiang] Hubei Minzu Univ, Coll Intelligent Syst Sci & Engn, Enshi 445000, Peoples R China.;[Tan, Wenhu] Cent China Normal Univ, Dept Phys Sci & Technol, Wuhan 430079, Peoples R China.
通讯机构：
[Yan Wang] S;School of Chemical and Environmental Engineering, Hubei Minzu University, Enshi 445000, PR China
关键词：
Nature-inspired;Branch-leaf structure;Electronic structure regulation;Flexibility;Room-temperature;NO2 gas sensor
摘要：
Flexible room-temperature (RT) gas sensors are highly desirable due to their low power consumption and wearability. However, it is very challenging to integrate excellent mechanical flexibility and superior gas sensing properties. Here, polyacrylonitrile (PAN) nanofiber/cobalt-doping SnS2 nanosheets with nature-inspired "branch-leaf" structure was well tailored by directly grown Co-SnS2 ultrathin nanosheets on PAN nanofiber for the first time. With the interfacial bonding interaction between PAN substrate and SnS2 nanosheets, the geometrical deformability of composite structure, the interfacial bonding force, stress distribution, transfer and dissipation will be enhanced. Moreover, the electronic structure and S vacancy are regulated by Co-doping, then improve the gas transmission/diffusion, gas sensitive reactivity and carrier transfer/transport properties. The integrated RT NO2 gas sensor exhibits excellent flexibility (minimum radius of curvature is 3.9 mu m), high response, fast response/recovery speed (6.2 and 27.5/60 s). Meanwhile, it possesses a low detection limit and long-term sta-bility. This comprehensive strategy for the integration of mechanical and gas sensitive properties unlocks the inherent bottlenecks of conventional film-based gas sensors and open a new design avenue for the development of flexible electronics.
摘要：
In this paper, we propose a scheme for measurement-based control of hybrid Einstein-Podolsky-Rosen (EPR) entanglement and steering between distant macroscopic mechanical oscillator and yttrium iron garnet (YIG) sphere in a system of an electromechanical cavity unidirectionally coupled to an electromagnonical cavity. We reveal that when the output of the electromagnonical cavity is continuously monitored by homodyne detection, not only the phonon-magnon entanglement and steering but also the purities of the phononic, magnonic and phonon-magnon states are considerably enhanced. We also find that the measurement can effectively retrieve the magnon-to-phonon steering, which is not yet obtained in the absence of the measurement. We show that unconditional phonon-magnon entanglement and steering can be achieved by introducing indirect feedback to drive the magnon and mechanical subsystems. The long-distance macroscopic hybrid entanglement and steering can be useful for, e.g., fundamental tests for quantum mechanics and quantum networks.
期刊：
EUROPEAN PHYSICAL JOURNAL C,2023年83(1):1-14 ISSN：1434-6044
通讯作者：
Cao, S.;Deng, J.
作者机构：
[Li, Xiaowen; Deng, Jian; Cao, Shanshan] Shandong Univ, Inst Frontier & Interdisciplinary Sci, Qingdao 266237, Shandong, Peoples R China.;[Jiang, Ze-Fang] Hubei Engn Univ, Dept Phys & Elect Informat Engn, Xiaogan 432000, Hubei, Peoples R China.;[Jiang, Ze-Fang] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.;[Jiang, Ze-Fang] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.
通讯机构：
[Shanshan Cao; Jian Deng] I;Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, China<&wdkj&>Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, China
摘要：
Extremely large angular orbital momentum can be produced in non-central heavy-ion collisions, leading to a strong transverse polarization of partons that scatter through the quark-gluon plasma (QGP) due to spin-orbital coupling. We develop a perturbative approach to describe the formation and spacetime evolution of quark polarization inside the QGP. Polarization from both the initial hard scatterings and interactions with the QGP have been consistently described using the quark-potential scattering approach, which has been coupled to realistic initial condition calculation and the subsequent
$$(3+1)$$
-dimensional viscous hydrodynamic simulation of the QGP for the first time. Within this improved approach, we have found that different spacetime-rapidity-dependent initial energy density distributions generate different time evolution profiles of the longitudinal flow velocity gradient of the QGP, which further lead to an approximately 15% difference in the final polarization of quarks collected on the hadronization hypersurface of the QGP. Therefore, in addition to the collective flow coefficients, the hyperon polarization may serve as a novel tool to help constrain the initial condition of the hot nuclear matter created in high-energy nuclear collisions.
摘要：
Currently, most fatigue driving detection methods rely on complex neural networks whose feasibility in hardware implementation needs to be further improved. This paper proposes an embedded device-oriented fatigue driving detection method based on a lightweight YOLOv5s. Firstly, a YOLOv5s face detection network with a parametric-free attention mechanism is designed to enhance the focus on face regions during face detection. Then, a practical facial landmark detector model is improved by integrating multi-scale feature fusion with Ghost module, which can adapt to the variations brought by different scale targets. Next, a fatigue determination approach is investigated by using multiple features of the face. Finally, experiments of the proposed detection model with the public YawDD dataset are implemented on the PC platform and the embedded device, respectively. The experimental results demonstrate that the proposed method achieves a detection accuracy of 95.3% and a processing speed of 22FPS on the PC platform. Meanwhile, the hardware test on an Orange Pi5 embedded device achieves a detection accuracy of 93.3% and a processing speed of 12FPS, which has good prospects for applications.
摘要：
As an novel paradigm, computation offloading in the mobile edge computing (MEC) system can effectively support the resource-intensive applications for the mobile devices (MD) equipped with limited computing capability. However, the hostile radio transmission and data leakage during the offloading process may erode the MEC system's potential. To tackle these hindrances, we investigate an IRS-assisted secure MEC system with eavesdroppers, where the intelligent reflecting surface (IRS) is deployed to enhance the communication between the MD and the AP equipped with edge servers and the malicious eavesdroppers may attack the wireless data offloaded by MD. The MD opt for offloading part of the tasks to the edge server for execution to support the computation-intensive applications. Moreover, the relevant latency minimization problem is formulated by optimizing the offloading ratio, the allocation of edge server computing capability, the multiple-user-detection (MUD) matrix and the IRS phase shift parameters, subject to the constraints of edge computation resource and practical IRS phase shifts. Then, the original problem is decouple into two subproblem, and the computing and communication subproblems are alternatively optimized by block coordinate descent (BCD) method with low complexity. Finally, simulation results demonstrate that the proposed scheme can significantly enhance the performance of secure offloading in the MEC system.(c) 2023 Elsevier B.V. All rights reserved.
作者机构：
[Xia, Qiaoqiao; Wang, Ji; Wang, J; Ma, Xinxin] Cent China Normal Univ, Dept Elect & Informat Engn, Wuhan, Peoples R China.;[Zheng, Le] Beijing Inst Technol, Sch Informat & Elect, Beijing, Peoples R China.;[Yang, Kai] Tongji Univ, Dept Comp Sci, Shanghai, Peoples R China.;[Chen, Zhao] Tsinghua Univ, Beijing Natl Res Ctr Informat Sci & Technol, Beijing, Peoples R China.
会议名称：
IEEE Wireless Communications and Networking Conference (WCNC)
会议时间：
MAR 26-29, 2023
会议地点：
Glasgow, SCOTLAND
会议主办单位：
[Wang, Ji;Ma, Xinxin;Xia, Qiaoqiao] Cent China Normal Univ, Dept Elect & Informat Engn, Wuhan, Peoples R China.^[Zheng, Le] Beijing Inst Technol, Sch Informat & Elect, Beijing, Peoples R China.^[Yang, Kai] Tongji Univ, Dept Comp Sci, Shanghai, Peoples R China.^[Chen, Zhao] Tsinghua Univ, Beijing Natl Res Ctr Informat Sci & Technol, Beijing, Peoples R China.
会议论文集名称：
IEEE Wireless Communications and Networking Conference
关键词：
Internet of Things;ultra-dense cloud radio access network;energy harvesting;successive convex approximation
摘要：
This paper studies the secrecy wireless information and power transfer problem in ultra-dense cloud radio access network (UD-CRAN) with wireless fronthaul, which is a promising framework for future Internet of Things (IoT). The transmission schemes of wireless fronthaul and access links are jointly designed, while addressing the characteristics of ultra-dense network such as base station diversity and high probability of line-of-sight transmission. Specifically, we employ the idea of block diagonalization to deal with the fronthaul interference, which support multi-stream fronthaul transmission for each remote radio head (RRH). We then jointly optimize the power allocation in the fronthaul and the resource allocation in the access link which includes beamforming for information and energy transmission, on/off of RRHs, and user-RRH association. In order to solve the formulated mixed integer non-convex optimization problem, we leverage the sparsity of beamforming vectors brought by the ultra-dense RRHs. We then solve the reformulated problem by employing the successive convex approximation approach. Finally, numerical results are presented to demonstrate the effectiveness of the proposed scheme.
通讯机构：
[Yang, Z ] C;[Hu, P ] H;Hubei Univ Technol, Sch Sci, Wuhan 430068, Peoples R China.;Cent China Normal Univ, Coll Phys Sci & Technol, Inst Nanosci & Nanotechnol, Wuhan 430079, Peoples R China.
关键词：
copper ion storage;V2O5;charge-storage mechanism
摘要：
Copper metal is a promising anode in aqueous batteries due to its low price, noble reaction potential (0.34 V), high theoretical specific capacity, abundance and chemical stability. However, only a few copper ion storage materials have been reported. Herein, layered vanadium pentoxide is chosen to store copper ions for the first time. Ex situ XRD reveals a unique two phase transition process during cycling. The V2O5 electrode shows stable copper ion storage performance. It delivers 91.9 mAh g(-1) for the first cycle with a cycle life of as high as 4000 cycles at 1.0 A g(-1). This work provides an intriguing copper ion storage material and expands the available options of electrode materials for copper ion storage.
作者机构：
[Ketel, T.; Tuning, N.; Mauri, A.; Usachov, A.; Lukashenko, V.; Galati, M. D.; Heijhoff, K.; Veronesi, M.; Akiba, K.; Aaij, R.; Snoch, A.; van Beuzekom, M.; Biolchini, A.; Jans, E.; Greeven, L. M.; Geertsema, R. E.; Pellegrino, A.; Gabriel, E.; Merk, M.; Butter, J. S.; Koppenburg, P.; Soares, M. Senghi; Klaver, S.; Gras, C. Sanchez; Raven, G.; Sole, S. Ferreres; Kostiuk, I.; Schubiger, M.; Hulsbergen, W.] Nikhef Natl Inst Subat Phys, Amsterdam, Netherlands.;[Baptista de Souza Leite, J.; De Freitas Carneiro Da Graca, U.; Massafferri, A.; Cruz Torres, M.; De Miranda, J. M.; Falcao, L. N.; Bediaga, I. B.; Leite, JBD; Gomes, A.; Torres Machado, D.; dos Reis, A. C.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.;[Lopes, J. H.; Polycarpo, E.; Souza De Paula, B.; Souza De Almeida, F. L.; Gandelman, M.; Rangel, M. S.; Ferreira Rodrigues, F.; Hicheur, A.; Otalora Goicochea, J. M.; De Paula, L.; Nasteva, I.; Amato, S.; Meyer Garcia, L.] Univ Fed Rio de Janeiro, Rio De Janeiro, Brazil.;[Wang, Z.; Qu, S.; Qin, N.; Ren, Z.; Xu, L.; Tou, D. Y.; Wang, J.; Li, A.; Hu, X.; Tan, Y.; Gu, C.; Gong, G.; Kang, Y.; Qi, H. R.; Chen, C.; Luo, Y.; Yang, D.; Mu, H.; Zeng, M.; Dong, C.; Zhang, L.; Gan, Y.] Tsinghua Univ, Ctr High Energy Phys, Beijing, Peoples R China.;[Lu, Y.; Li, Y.; Ma, L.; Sheng, S.; Li, T.; Xu, L.; Wang, J.; Chen, S.; Tobin, M.; Miao, D.; Grieser, N. A.; Jiang, X.; Batsukh, B.; Zou, Q.; Liu, S.] Inst High Energy Phys, Beijing, Peoples R China.
通讯机构：
[Leite, JBD ] C;Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil.
摘要：
Searches for the rare hadronic decays B-0 -> p (p) over barp (p) over bar and B-s(0) -> p (p) over barp (p) over bar are performed using proton-proton collision data recorded by the LHCb experiment and corresponding to an integrated luminosity of 9 fb-1. Significances of 9.3 sigma and 4.0 sigma, including statistical and systematic uncertainties, are obtained for the B-0 -> p (p) over barp (p) over bar and B-s(0) -> p (p) over barp (p) over bar signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays B-0 -> J/psi(-> p (p) over bar )K*(0)(-> K+ pi(-) ) and B-s(0) -> J/psi(-> p (p) over bar )X phi(-> K+ K- ). The branching fractions are measured to be B(B-0 -> p (p) over barp (p) over bar) = (2.2 +/- 0.4 +/- 0.1 +/- 0.1) x 10(-8) and B(B-s(0) -> p (p) over barp (p) over bar) = (2.3 +/- 1.0 +/- 0.2 +/- 0.1) x 10(-8). In these measurements, the first uncertainty is statistical, the second is systematic, and the third one is due to the external branching fraction of the normalization channel.
摘要：
针对当前遥感卫星电荷耦合器件(CCD)相机幅宽越来越大, 速率越来越高, 现有相机模拟源设备数据输出带宽不足的问题, 提出并实现了一种基于非易失性存储器 Express(NVMe)的超高速多通道遥感相机模拟源设备。该设备利用现场可编程逻辑门阵列 (FPGA)实现 4组 NVMe SSD主机控制器, 完成对固态硬盘 (SSD)的读写操作; 同时利用 DMA控制器读取 DDR4中缓存数据, 数据经封装处理后通过光纤接口输出。实验结果表明: NVMe主机控制器的写平均速率可以达到 1.7 GBps, 读平均速率达到 3.2 GBps。模拟源系统整体存储容量 8 TB, 对外输出带宽高达 80 Gbps, 支持 8路光纤接口输出。该模拟源具有较强的稳定性及良好的可扩展性, 已成功应用在某遥感卫星 CCD相机模拟源系统中, 为数传等设备的测试以及调试提供了充分保障。 Aiming at the problem that the current remote sensing satellite Charge Couple Device (CCD) camera has an increasing width and speed, and the output bandwidth of existing camera simulator is insufficient, an Non-Volatile Memory express(NVMe) based ultrahigh-speed multi-channel remote sensing camera simulator is proposed and implemented. This simulator employs a Field Programmable Gate Array(FPGA) to implement four groups of NVMe SSD host controllers and complete the read and write operations on the Solid State Drive(SSD). The Direct Memory Access(DMA) controller is utilized to read the cache data in DDR4, and the data is output through the optical fiber interface after being encapsulated. Experimental results show that the average write rate of the NVMe host controller can reach 1.7 GBps, and the average read rate can reach 3.2 GBps. The overall storage capacity of the simulator is 8 TB, the external output bandwidth is up to 80 Gbps, and it supports eight-way optical fiber interface outputs. This simulator with strong stability and good scalability, has been successfully applied in a remote sensing satellite CCD camera simulator system, which provides sufficient guarantee for the testing and debugging of device such as data transmission.
作者机构：
[Chen, Wei; Chen, W] Univ Chinese Acad Sci, Sch Nucl Sci & Technol, Beijing 100049, Peoples R China.;[Pang, Longgang; Wang, Xin-Nian; Yang, Zhong] Cent China Normal Univ, Key Lab Quark & Lepton Phys, MOE, Wuhan 430079, Peoples R China.;[Pang, Longgang; Wang, Xin-Nian; Yang, Zhong] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;[He, Yayun] South China Normal Univ, Guangdong Prov Key Lab Nucl Sci, Inst Quantum Matter, Guangzhou 510006, Peoples R China.;[Luo, Tan] Univ Santiago Compostela, Inst Galego Fis Altas Enerxias IGFAE, Galicia, Spain.
会议名称：
29th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions Quark Matter
会议时间：
APR 04-10, 2022
会议地点：
Krakow, POLAND
会议主办单位：
[Chen, Wei] Univ Chinese Acad Sci, Sch Nucl Sci & Technol, Beijing 100049, Peoples R China.^[Yang, Zhong;Pang, Longgang;Wang, Xin-Nian] Cent China Normal Univ, Key Lab Quark & Lepton Phys, MOE, Wuhan 430079, Peoples R China.^[Yang, Zhong;Pang, Longgang;Wang, Xin-Nian] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.^[He, Yayun] South China Normal Univ, Guangdong Prov Key Lab Nucl Sci, Inst Quantum Matter, Guangzhou 510006, Peoples R China.^[Luo, Tan] Univ Santiago Compostela, Inst Galego Fis Altas Enerxias IGFAE, Galicia, Spain.^[Wang, Xin-Nian] Lawrence Berkeley Natl Lab, Nucl Sci Div, MS 70R0319, Berkeley, CA 94720 USA.
摘要：
Diffusion wake is an unambiguous part of the jet-induced medium response in high-energy heavy-ion collisions that leads to a depletion of soft hadrons in the opposite direction of the jet propagation. Using a coupled linear Boltzmann transport and hydro model, we identify a valley structure caused by the diffusion wake on top of a ridge from the initial multiple parton interaction (MPI) in the jet-hadron correlation as a function of azimuthal angle and rapidity. This gives rise to the unambiguous signals of the diffusion wake on soft hadrons in the opposite direction of the jets, which are reflected in the depletion in azimuthal angle distribution after subtraction of the contributions from MPI with a mixed-event procedure, and the double-peak structure in the rapidity distribution. We further employ the longitudinal and transverse gradient jet tomography for the first time to localize the initial jet production positions in Z/gamma-jet events in which the effect of the diffusion wake is apparent in Z/gamma-hadron correlation even without the subtraction of MPI.
摘要：
Accurate determination of the thermal rate constants for combustion reactions is a highly challenging task, both experimentally and theoretically. Machine learning has been proven to be a powerful tool to predict reaction rate constants in recent years. In this work, three supervised machine learning algorithms, including XGB, FNN, and XGB-FNN, are used to develop quantitative structure-property relationship models for the estimation of the rate constants of hydrogen abstraction reactions from alkanes by the free radicals CH(3), H, and O. The molecular similarity based on Morgan molecular fingerprints combined with the topological indices are proposed to represent chemical reactions in the machine learning models. Using the newly constructed descriptors, the hybrid XGB-FNN algorithm yields average deviations of 65.4%, 12.1%, and 64.5% on the prediction sets of alkanes + CH(3), H, and O, respectively, whose performance is comparable and even superior to the corresponding one using the activation energy as a descriptor. The use of activation energy as a descriptor has previously been shown to significantly improve prediction accuracy ( Fuel 2022, 322, 124150) but typically requires cumbersome ab initio calculations. In addition, the XGB-FNN models could reasonably predict reaction rate constants of hydrogen abstractions from different sites of alkanes and their isomers, indicating a good generalization ability. It is expected that the reaction descriptors proposed in this work can be applied to build machine learning models for other reactions.
摘要：
The zero-degree calorimeter (ZDC) plays a crucial role toward determining the centrality in the Cooling-Storage-Ring External-target Experiment (CEE) at the Heavy Ion Research Facility in Lanzhou. A boosted decision tree (BDT) multi-classification algorithm was employed to classify the centrality of the collision events based on the raw features from ZDC such as the number of fired channels and deposited energy. The data from simulated
$$^{238}\textrm{U}$$
+
$$^{238}\textrm{U}$$
collisions at 500
$$\mathrm{MeV/u}$$
, generated by the IQMD event generator and subsequently modeled using the GEANT4 package, were employed to train and test the BDT model. The results showed the high accuracy of the multi-classification model adopted in ZDC for centrality determination, which is robust against variations in different factors of detector geometry and response. This study demonstrates the good performance of CEE-ZDC in determining the centrality in nucleus–nucleus collisions.
摘要：
This study presents an electronics system for cosmic X-ray polarization detection (CXPD). The CXPD was designed as a high-sensitivity soft X-ray polarimeter with a measurement energy range of 2–10 keV carried by a CubeSat. A stable and functionally complete electronics system under power and space constraints is a key challenge. The complete CXPD electronics system (CXPDES) comprises hardware and firmware. CXPDES adopts a three-layer electronic board structure based on functionality and available space. Two gas pixel detectors (GPDs) were placed on the top layer board, and CXPDES provided the GPDs with voltages up to
$$-$$
4000V. Each GPD signal was digitized, compressed, encoded, and stored before being transmitted to the ground. The CXPDES provided stable and high-speed communication based on a scheme that separated command and data transmission, and it supports the CXPDES in-orbit upgrade. In addition, environmental monitors, silicon photomultiplier (SiPM) triggers, power management, GPDs configuration, and mode switches were included in the overall operating logic of the CXPDES. The results obtained by testing the CXPDES showed that it satisfied all the requirements of CXPD. The CXPDES provides design experience and technological readiness for future large-area X-ray polarimetry missions.
