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Effects of the cosmological constant on chaos in an FRW scalar field universe

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Research in Astronomy and Astrophysics 2009年第11期9卷 1185-1191页

作者： Da-zhu Ma Xin Wu Shuang-Ying Zhong Department of Physics Nanchang University Nanchang 330031 China Department of Physics Hubei University for Nationalities Enshi 445000 China

The dependence of chaos on two parameters of the cosmological constant and the self-interacting coefficient in the imaginary phase space for a closed Friedman- Robertson-Walker （FRW） universe with a conformally coupled scalar field, as the full understanding of the dependence in real phase space, is investigated numerically. It is found that Poincar6 plots for the two parameters less than 1 are almost the same as those in the absence of the cosmological constant and self-interacting terms. For energies below the energy threshold of 0.5 for the imaginary problem in which there are no cosmological constant and self-interacting terms, an abrupt transition to chaos occurs when at least one of the two parameters is 1. However, the strength of the chaos does not increase for energies larger than the threshold. For other situations of the two parameters larger than 1, chaos is weaker, and even disappears as the two parameters increase.

关键词： cosmology cosmological parameters -- methods numerical

Combo Packet:An Encryption Traffic Classification Method Based on Contextual Information

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Computers, Materials & Continua 2024年第4期79卷 1223-1243页

作者： Yuancong Chai Yuefei zhu Wei Lin Ding Li State Key Laboratory of Mathematical Engineering and Advanced Computing Information Engineering UniversityZhengzhou450001China

With the increasing proportion of encrypted traffic in cyberspace, the classification of encrypted traffic has becomea core key technology in network supervision. In recent years, many different solutions have emerged in this *** methods identify and classify traffic by extracting spatiotemporal characteristics of data flows or byte-levelfeatures of packets. However, due to changes in data transmission mediums, such as fiber optics and satellites,temporal features can exhibit significant variations due to changes in communication links and transmissionquality. Additionally, partial spatial features can change due to reasons like data reordering and *** with these challenges, identifying encrypted traffic solely based on packet byte-level features is significantlydifficult. To address this, we propose a universal packet-level encrypted traffic identification method, ComboPacket. This method utilizes convolutional neural networks to extract deep features of the current packet andits contextual information and employs spatial and channel attention mechanisms to select and locate effectivefeatures. Experimental data shows that Combo Packet can effectively distinguish between encrypted traffic servicecategories (e.g., File Transfer Protocol, FTP, and Peer-to-Peer, P2P) and encrypted traffic application categories (e.g.,BitTorrent and Skype). Validated on the ISCX VPN-non VPN dataset, it achieves classification accuracies of 97.0%and 97.1% for service and application categories, respectively. It also provides shorter training times and higherrecognition speeds. The performance and recognition capabilities of Combo Packet are significantly superior tothe existing classification methods mentioned.

关键词： Encrypted traffic classification packet-level convolutional neural network attention mechanisms

Environmental evolution recorded by multi-proxy evidence in Lake Chenghai sediments, Yunnan Province during recent 100 years

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Chinese Journal Of Geochemistry 2013年第1期32卷 47-55页

作者： zhu Zhengjie CHEN Jing'an REN Shicong ZENG Yan The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Chongqing Key Laboratory of Exogenic Mineralization and Mine Environment Chongqing Institute of Geology and Mineral Resources Chongqing Research Center of State Key Laboratory of Coal Resources and Safe Mining

Lacustrine sediments can provide potential information about environmental changes in the past. On the basis of high-resolution multi-proxy analysis including carbon and nitrogen contents of organic matter, C/N ratios, inorganic carbon contents, and carbon and oxygen isotopic composition of carbonate, together with precise 137Cs dating, the environmental evolution of Lake Chenghai, Yunnan Province, during the past 100 years has been investigated. It is shown that the carbonate in Lake Chenghai is authigenic, and the organic matter is mainly derived from aquatic plants and algae, instead of terrestrial-source materials. The environmental evolution of Lake Chenghai can be diverged into three periods with the contrasting characteristics during the past 100 years. Before 1940, the stable carbon and oxygen isotope values, the poor correlation between them and the lower carbon and nitrogen contents of organic matter suggested that Lake Chenghai was open, and the lake water was oligotrophic during that period. During 1940-1993, the negative δ13C values and the gradual increase of carbon and nitrogen contents of organic matter and C/N ratios indicated that the eutrophication was aggravated. The closeness of Lake Chenghai and human activities may be responsible for this eutrophication. After 1993, notable increases in carbon and oxygen isotopic values of carbonate, carbon and nitrogen contents of organic matter, C/N ratios and inorganic carbon contents demonstrated that the increase of lacustrine productivity and the serious eutrophication were resulted from strong human activities. Therefore, the multi-proxy in Lake Chenghai sediments has reliably recorded the natural environmental evolution and the impacts from human activities.

关键词：湖泊沉积物环境演变多代理云南省程海氧同位素组成水体富营养化人类活动影响

Dual Space SVDD Based Radar Target Recognition from HRRP

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Chinese Journal of Electronics 2014年第2期23卷 419-425页

作者： XIAO Huaitie FENG Guoyu zhu Yongfeng HUANG Mengjun Science and Technology on Automatic Target Recognition Laboratory National University of Defense Technology

In radar target recognition based on kernel method, Support vector data description(SVDD) has been applied to High resolution range profiles(HRRPs)recognition. In this paper, first, three distribution models,i.e., Membership model, Cloud model, Gaussian mixture model, are developed to describe distribution characteristics of HRRPs in extended space. Secondly, test HRRPs in multi-target hypersphere spaces are classified, in accordance with their multi-space distributing characteristics,into two types, i.e., shrink sample and slack sample. Determination of the property of a test sample is achieved by using the minimum relative distance for shrink samples and three distribution models for slack samples, respectively. Thus three HRRP recognition methods based on dual space SVDD are formed. The extensive experiment results for HRRPs of four planes show that the proposed methods have better recognition performance than the recognition method based on single space SVDD.

关键词： High resolution range profile Support vector data description Membership model Cloud model Gaussian mixture model

Fluctuations of Single-Mode Laser Driven by Two Different Kinds of Colored Noise

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Communications in Theoretical Physics 2006年第4期45卷 630-636页

作者： WU Dan LUO Xiao-Qin zhu Shi-Qun School of Physical Science and Technology Suzhou University Suzhou 215006 China

A single-mode laser with coupling between additive and multiplicative noise terms is investigated when the multiplicative noise and the coupling between two noise terms are colored fluctuations with finite correlation times T1 and T2. Combining the unified colored noise approximation （UCNA） and the functional analysis, the stationary probability distribution （SPD） and the variance of the laser intensity is derived. It is found that the colored nature of multiplicative noise and the coupling strength between two noise terms can affect both the structure and the height of the SPD, while the colored nature of the coupling between two noise terms can only affect the height of the SPD. The multiplicative noise can enhance the intensity fluctuations while the additive noise can reduce the fluctuations in a laser system. Numerical simulations are presented and consistent to the analytical results.

关键词： single-mode laser colored noise fluctuation coupling variance

Numerical Study on the Suitability of Passive Solar Heating Technology Based on Differentiated Thermal Comfort Demand

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Computer Modeling in Engineering & Sciences 2022年第8期132卷 627-660页

作者： Xiaona Fan Qin Zhao Guochen Sang Yiyun zhu School of Civil Engineering and Architecture Xi’an University of TechnologyXi’an710048China

Indoor thermal comfort and passive solar heating technologies have been extensively ***,few studies have explored the suitability of passive solar heating technologies based on differentiated thermal comfort *** work took the rural dwellings in Northwest China as the research ***,the current indoor and outdoor thermal environment in winter and the mechanism of residents’differentiated demand for indoor thermal comfort were obtained through tests,questionnaires,and statistical ***,a comprehensive passive optimized design of existing buildings was conducted,and the validity of the optimized combination scheme was explored using DesignBuilder ***,the suitability of passive solar heating technology for each region in Northwest China was analyzed based on residents’differentiated demand for indoor thermal *** regions were then classified according to the suitability of the technology for *** results showed that the indoor heating energy consumption was high and the indoor thermal environment was not ideal,yet the solar energy resources were *** comfort temperature indexes that match the functional rooms and usage periods were *** the buildings with the optimized combination scheme,the average indoor temperature was increased significantly and the temperature fluctuation was decreased *** regions in Northwest China were suitable for the development of passive solar heating *** on the obtained suitability of the technology for the regions of Northwest China,these were classified into most suitable,more suitable,less suitable,and unsuitable regions.

关键词： Rural dwellings differentiated thermal comfort demand optimization and simulation statistical analysis passive solar heating technology suitability

Activation of the Brain to Postpone Dementia: A Concept Originating from Postmortem Human Brain Studies

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Neuroscience Bulletin 2019年第2期35卷 253-266页

作者： Qiong-Bin zhu Ai-Min Bao Dick Swaab Department of Neurology Sir Run Run Shaw HospitalZhejiang University School of Medicine Department of Neurobiology Key Laboratory of Medical Neurobiology of the Ministry of Health of China Zhejiang Province Key Laboratory of Neurobiology Zhejiang University School of Medicine Netherlands Institute for Neuroscience Institute of the Royal Netherlands Academy of Arts and Sciences

Alzheimer's disease(AD) is characterized by decreased neuronal activity and atrophy, while hyperactivity of neurons seems to make them resistant to aging and neurodegeneration, a phenomenon which we have paraphrased as ‘use it or lose it'. Our hypothesis proposes that(1) during their functioning, neurons are damaged;(2)accumulation of damage that is not repaired is the basis of aging;(3) the vulnerability to AD is determined by the genetic background and the balance between the amount of damage and the efficiency of repair, and(4) by stimulating the brain, repair mechanisms are stimulated and cognitive reserve is increased, resulting in a decreased rate of aging and risk for AD. Environmental stimulating factors such as bilingualism/multilingualism, education, occupation, musical experience, physical exercise, and leisure activities have been reported to reduce the risk of dementia and decrease the rate of cognitive decline, although methodological problems are present.

关键词： Dementia Genes Environmental stimulation Brain activation Cognitive reserve Use it or lose it

Photopatternable PEDOT:PSS/PEG hybrid thin film with moisture stability and sensitivity

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Microsystems & Nanoengineering 2017年第1期3卷 358-366页

作者： Zijie zhu Gaomai Yang Ruya Li Tingrui Pan Micro-Nano Innovations(MiNI)Laboratory Department of Biomedical EngineeringThe University of CaliforniaDavisCA 95616USA Department of Electrical and Computer Engineering The University of CaliforniaDavisCA 95616USA

Degradation and delamination resulting from environmental humidity have been technically challenging for poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)thin-film *** overcome this problem,we introduced a one-step photolithographic method to both pattern and link a PEDOT:PSS film onto a poly(ethylene glycol)(PEG)layer as a hybrid thin film structure on a flexible *** film exhibited excellent long-term moisture stability(more than 10 days)and lithographic resolution(as low as 2μm).Mechanical characterizations were performed,including both stretching and bending tests,which illustrated the strong adhesion present between the PEDOT:PSS and PEG layers as well as between the hybrid thin film and ***,the hybrid moisture-absorbable film showed a quick response of its permittivity to environmental humidity variations,in which the patterned PEDOT:PSS layer served as an electrode and the PEG layer as a moisture-sensing *** tracking over various parts of the body surface as well as breath rate measurement under the nose were successfully carried out as demonstrations,which illustrated the potential utility of this stable hybrid thin film for emerging flexible and wearable electronic applications.

关键词： breath rate measurement humidity sensor hybrid thin film moisture stability one-step photopatterning PEDOT:PSS perspiration tracking

Multiple Limit Cycles in an Immune System

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 177-184页

作者： Xun-cheng Huan Le-min zhu Minaya Villasana Yangzhou Polytechnic University Yangzhou 225009 China Universidad Simon Bolivar Caracas 1080-A Venezuela

The nonlinear oscillatory phenomenon has been observed in the system of immune response, which corresponds to the limit cycles in the mathematical models. We prove that the system simulating an immune response studied by Huang has at least three limit cycles in the system. The conditions for the multiple limit cycles are useful in analyzing the nonlinear oscillation in immune response.

关键词： Immune response multiple limit cycle, oscillation