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Electron Impact Excitation of Xenon from the Ground State and the Metastable State to the 5p57p Levels

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Chinese Physics Letters 2014年第3期31卷 51-54页

作者： CHEN Zhan-Bin DONG Chen-Zhong XIE Lu-You jiang jun Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province College of Physics and Electronic Engineering Northwest Normal University Lanzhou 730070 Key Joint Laboratory of Atomic and Molecular Physics Northwest Normal University and Institute of Modern Physics of Chinese Academy of Sciences Lanzhou 730070

Electron impact excitation cross sections from the ground state and the lowest metastable state 5p56s J=2 to the excited states of the 5p57p configuration of xenon are calculated systematically using the fully relativistic distorted wave method. Special attention is paid to the configuration interaction effects in the wave-function expansion of target states. The results are in good agreement with the recent experimental data by jung et al. [Phys. Rev. A 80 （2009） 062708] over the measured energy range. These accurate theoretical results can be used in the modeling and diagnosis of plasmas containing xenon.

关键词： XENON RESEARCH GROUND state energy METASTABLE states ELECTRONIC excitation -- Research WAVE functions

Dynamic Subcarrier Assignment for OFDM-PON Network Based on RSOA for ACCORDANCE

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China Communications 2014年第6期11卷 81-88页

作者： LIU Zhuo ZHANG Min jiang jun ZHAN Yueying CHEN Xue State Key Lab. of Information Photonics and Optical Communications Beijing Univ. of Posts & Telecom.10 Xitucheng Road

In this paper, we overview the principle of Orthogonal Frequency Division Multiplexing Passive Optical Network （OFDM-PON） systems, with a particular focus on upstream architectures capable of achieving 10Gbit/s colorless upstream transmission using Reflective Semiconductor Optical Amplifier （RSOA）. We propose an architecture of RSOA based OFDM-PON which can achieve 10Gbit/s upstream transmission over a single wavelength. A novel Dynamic Subcarrier Assignment （DSA） algorithm is also proposed to support my architecture, namely Service based Polling in Pipeline （SPP） dynamic subcarrier algorithm. A simulation was conducted to study the performance of SPP algorithm. Compared with the traditional dynamic bandwidth allocation algorithms, service based polling meets the quality of in pipeline algorithm service requirements excellently, and adapts orthogonal frequency division multiplexing passive optical network better with higher bandwidth efficiency and lower algorithm complexity.

关键词： OFDM-PON RSOA DBA QoS SPP

TIM: threat context-enhanced TTP intelligence mining on unstructured threat data

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Cybersecurity 2022年第2期5卷 10-26页

作者： Yizhe You jun jiang Zhengwei jiang Peian Yang Baoxu Liu Huamin Feng Xuren Wang Ning Li Institute of Information Engineering Chinese Academy of SciencesBeijing100093China School of Cyber Security University of Chinese Academy of SciencesBeijing100029China College of Information Engineering Capital Normal UniversityBeijing100048China Beijing Electronic Science and Technology Institute Beijing102627China

TTPs (Tactics, Techniques, and Procedures), which represent an attacker’s goals and methods, are the long period and essential feature of the attacker. Defenders can use TTP intelligence to perform the penetration test and compensate for defense deficiency. However, most TTP intelligence is described in unstructured threat data, such as APT analysis reports. Manually converting natural language TTPs descriptions to standard TTP names, such as ATT&CK TTP names and IDs, is time-consuming and requires deep expertise. In this paper, we define the TTP classification task as a sentence classification task. We annotate a new sentence-level TTP dataset with 6 categories and 6061 TTP descriptions from 10761 security analysis reports. We construct a threat context-enhanced TTP intelligence mining (TIM) framework to mine TTP intelligence from unstructured threat data. The TIM framework uses TCENet (Threat Context Enhanced Network) to find and classify TTP descriptions, which we define as three continuous sentences, from textual data. Meanwhile, we use the element features of TTP in the descriptions to enhance the TTPs classification accuracy of TCENet. The evaluation result shows that the average classification accuracy of our proposed method on the 6 TTP categories reaches 0.941. The evaluation results also show that adding TTP element features can improve our classification accuracy compared to using only text features. TCENet also achieved the best results compared to the previous document-level TTP classification works and other popular text classification methods, even in the case of few-shot training samples. Finally, the TIM framework organizes TTP descriptions and TTP elements into STIX 2.1 format as final TTP intelligence for sharing the long-period and essential attack behavior characteristics of attackers. In addition, we transform TTP intelligence into sigma detection rules for attack behavior detection. Such TTP intelligence and rules can help defenders deploy lon

关键词： TTPs Threat intelligence Natural language processing(NLP) Advanced persistent threat(APT)

TriCTI:an actionable cyber threat intelligence discovery system via trigger-enhanced neural network

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Cybersecurity 2022年第3期5卷 18-33页

作者： Jian Lu junjie Yan jun jiang Yitong He Xuren Wang Zhengwei jiang Peian Yang Ning Li Institute of Information Engineering Chinese Academy of SciencesBeijing 100093China School of Cyber Security University of Chinese Academy of SciencesBejing 100029China College of Information Engineering Capital Normal UniversityBeijing 100048China

The cybersecurity report provides unstructured actionable cyber threat intelligence(CTI)with detailed threat attack procedures and indicators of compromise(IOCs),e.g.,malware hash or URL(uniform resource locator)of command and control *** actionable CTI,integrated into intrusion detection systems,can not only prioritize the most urgent threats based on the campaign stages of attack vectors(i.e.,IOCs)but also take appropriate mitigation measures based on contextual information of the ***,the dramatic growth in the number of cybersecurity reports makes it nearly impossible for security professionals to find an efficient way to use these massive amounts of threat *** this paper,we propose a trigger-enhanced actionable CTI discovery system(TriCTI)to portray a relationship between IOCs and campaign stages and generate actionable CTI from cybersecurity reports through natural language processing(NLP)***,we introduce the“campaign trigger”for an effective explanation of the campaign stages to improve the performance of the classification *** campaign trigger phrases are the keywords in the sentence that imply the campaign *** trained final trigger vectors have similar space representations with the keywords in the unseen sentence and will help correct classification by increasing the weight of the *** also meticulously devise a data augmentation specifically for cybersecurity training sets to cope with the challenge of the scarcity of annotation data *** with state-of-the-art text classification models,such as BERT,the trigger-enhanced classification model has better performance with accuracy(86.99%)and F1 score(87.02%).We run TriCTI on more than 29k cybersecurity reports,from which we automatically and efficiently collect 113,543 actionable *** particular,we verify the actionability of discovered CTI by using large-scale field data from VirusTotal(VT).The results demonstrate that the threat

关键词： Actionable cyber threat intelligence Campaign trigger Indicators of compromise(IOCs) Natural language processing(NLP)

Protecting User Privacy in a Multi-Path Information-Centric Network Using Multiple Random-Caches

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Journal of Computer Science & Technology 2017年第3期32卷 585-598页

作者： Wei-Bo Chu Li-Fang Wang Ze-jun jiang Chin-Chen Chang School of Computer Science and Technology Northwestern Polytechnical University Xi'an 710072 China Department of Information Engineering and Computer Science Feng Chia University Taichung Taiwan 40724 China

In-network caching is a fundamental mechanism advocated by information-centric networks （ICNs） for efficient content delivery. However, this new mechanism also brings serious privacy risks due to cache snooping attacks. One effective solution to this problem is random-cache, where the cache in a router randomly mimics a cache hit or a cache miss for each content request/probe. In this paper, we investigate the effectiveness of using multiple random-caches to protect cache privacy in a multi-path ICN. We propose models for characterizing the privacy of multi-path ICNs with random-caches, and analyze two different attack scenarios： 1） prefix-based attacks and 2） suffix-based attacks. Both homogeneous and heterogeneous caches are considered. Our analysis shows that in a multi-path ICN an adversary can potentially gain more privacy information by adopting prefix-based attacks. Furthermore, heterogeneous caches provide much better privacy protection than homogeneous ones under both attacks. The effect of different parameters on the privacy of multi-path random-caches is further investigated, and the comparison with its single-path counterpart is carried out based on numerical evaluations. The analysis and results in this paper provide insights in designing and evaluating multi-path ICNs when we take privacy into consideration.

关键词： information-centric network (ICN) user privacy cache snooping random-cache multi-path

Anharmonicity induced thermal modulation in stressed graphene

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Science China(Physics,Mechanics & Astronomy) 2017年第7期60卷 48-52页

作者： Jian jun jiang Wei Cheng Fu Ji Ge Chen Hong Zhao Department of Physics and Institute of Theoretical Physics and Astrophysics Xiamen University Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied PhysicsChinese Academy of Sciences

Thermal properties are essentially decided by atomic geometry and thus stress is the most direct way for manipulating. In this paper, we investigate stress modulation of thermal conductivity of graphene by molecular dynamics simulations and discuss the underlying microscopic mechanism. It is found that thermal conductivity of ftexural-free graphene increases with compression and decreases with strain, while thermal conductivity of flexural-included graphene decreases with both compression and strain. Such difference in thermal behavior originates from the changes in the anharmonicity of the interatomic potential, where the wrinkle scattering is responsible for the thermal conductivity diminishment in flexural-included graphene under strain. By comparing the results obtained from the Tersoff and AIREBO potentials, it is revealed that the degree of the symmetry of interatomic potential determines the thermal conductivity variation of graphene. Our results indicate that the symmetry of interatomic potential should be taken into careful consideration in constructing the lattice model of graphene.

关键词： graphene heat conduction thermal modulation stressed graphene anharmonicity

A Broadband 630-720 GHz Schottky Based Sub-Harmonic Mixer Using Intrinsic Resonances of Hammer-Head Filter

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China Communications 2019年第2期16卷 76-84页

作者： Yue He Yaoling Tian Li Miao jun jiang XianJin Deng Microsystem and Terahertz Research Center China Academy of Engineering Physics Institute of Electronic Engineering China Academy of Engineering Physics

An room temperature low noise anti-parallel Schottky diode based 630-720 GHz sub-harmonic mixer(SHM) is designed, built and measured. Intrinsic resonances in lowpass hammer-head filter have been adopted to prevent the LO and RF power leak from the IF channel, while greatly minimizing the transmission line size. The mixer consists of 15 um quartz terahertz circuit and 127 um Al2 O3 IF transformer circuit. An improved lumped element equivalent noise model of SBDs guarantees the accuracy of simulation. The measurement indicates that with local oscillating(LO)signal of 2-8 mW, the lowest double sideband(DSB) conversion loss is 8.2 dB at 645 GHz,and the best DSB noise temperature is 2800 K at 657 GHz. The 3 dB bandwidth of conversion loss is 75 GHz from 638 to 715 GHz. The work IF frequency band is above 20 GHz ranging from 1 to 20 GHz with-10 dB return loss.

关键词： erahertz sub-harmonic mixer hammer-head filter Schottky diode

Improving photoelectrochemical activity of dye sensitized solar cell by a bilayered electrode with an overlayer of mesoporous anatase TiO_2

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Particuology 2011年第3期9卷 222-227页

作者： jun jiang Jian Zhang Feng Gu Wei Shao Chunzhong Li Mengkai Lu Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and Engineering East China University of Science and Technology Shanghai 200237 China State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

For better performance of dye sensitized solar cells （DSSCs）, a bilayer structured electrode was constructed by employing a mesoporous anatase TiO2 overlayer above a commercial P25 TiO2 nanoparticles underlayer. The mesoporous anatase TiO2, prepared through a facile surfactant-assisted sol-gel process, possessed large pore size and well inter-connected network structure, both beneficial for dye adsorption and electron transfer. The dye adsorption capability of the mesoporous TiO2 was nearly twice that of the P25 counterpart. In the electrode, the mesoporous TiO2 film enhanced both dye adsorption and lightharvest, to increase photocurrent （Jsc） from 12.32 to 14.78 mA/cm^2. Compared to the single P25 TiO2 film, the synergy of the mesoporous TiO2 and the P25 TiO2 nanoparticle films in the electrode resulted in a 24% improvement in light-to-electricity conversion efficiency （η）. This bilayered electrode provides an alternative approach for further developing a photovoltaic device with better cell performance.

关键词： Meosporous TiO2 Preparation Bilayer structured electrode Dye sensitized solar cells

Achieving high ductility and strength in magnesium alloy through cryogenic-hot forming

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Journal of Magnesium and Alloys 2023年第9期11卷 3130-3140页

作者： Kai Zhang Zhutao Shao Joseph Robson Yan Huang Jinghua Zheng jun jiang Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Department of Mechanical Engineering University College LondonLondon WC1E 7JEUK Department of Materials The University of ManchesterManchester M13BBUK BCAST Institute of Materials and ManufacturingBrunel University LondonUxbridge UB83PHUK College of Material Science and Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Magnesium alloys are the lightest structural alloys and have attracted substantial research attention in the past two decades. However, their mechanical properties, including ductility and strength, are limited after forming due to the formation of coarse grains and strong texture. This study proposes and proves a new cryogenic-hot forming process concept. Cryogenic deformation is imposed before the hot deformation. The effect of the cryogenic step has been compared with a conventional direct hot deformation process. The mechanical properties, microstructure,and texture of both the novel and conventional process routes have been compared. The cryogenic-hot deformed sample exhibits the highest ductility and fracture strength(ultimate tensile strength: 321 MPa, ductility: 21%) due to effective grain refinement and texture weakening by cryogenically formed twin-twin interaction induced recrystallisation. The proposed cryogenic-hot forming process can be a potential innovative manufacturing method for producing high-performance magnesium components.

关键词： Magnesium alloys Dynamic recrystallisation Twinning Cryogenic deformation