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Extending ssD Lifespan with Comprehensive Non-Volatile Memory-Based Write Buffers

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Journal of Computer science & Technology 2019年第1期34卷 113-132页

作者： Ziqi fan Dongchul Park Department of Computer science and Engineering University of Minnesota-Twin CitiesMinneapolisMN 55455U.S.A. Division of Computer and Electronic systems Engineering Hankuk University of Foreign Studies Gyeonggi-do 17035South Korea

New non-volatile memory (NVM)technologies are expected to replace main memory DRAM (dynamic random access memory)in the near *** flash technological breakthroughs have enabled wide adoption of solid state drives (ssDs)in storage ***,flash-based ssDs,by nature,cannot avoid low endurance problems because each cell only allows a limited number of *** can give rise to critical ssD reliability *** many ssD write operations eventually cause many ssD erase operations,reducing ssD write traffic plays a crucial role in ssD reliability. This paper proposes two NVM-based buffer cache policies which can work together in different layers to maximally reduce ssD write traffic:a main memory buffer cache design named Hierarchical Adaptive Replacement Cache (H-ARC)and an internal ssD write buffer design named Write Traffic Reduction Buffer (WRB).H-ARC considers four factors (dirty,clean, recency,and frequency)to reduce write traffic and improve cache hit ratios in the *** reduces block erasures and write traffic further inside an ssD by effectively exploiting temporal and spatial *** two comprehensive schemes significantly reduce total ssD write traffic at each different layer (i.e.,host and ssD)by up to ***,they help extend ssD lifespan without system performance degradation.

关键词： buffer cache policy write buffer non-volatile memory solid state drive flash memory

Non-linear characteristics of Rayleigh-Taylor instable perturbations

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Acta Mechanica sinica 2008年第2期24卷 143-149页

作者： Zhengfeng fan Jisheng Luo Department of Fluid Mechanics School of MechanicsTianjin University Tianjin 300072 China

The direct numerical simulation method is adopted to study the non-linear characteristics of Rayleigh-Taylor instable perturbations at the ablation front of a 200 μm planar CH ablation target. In the simulation, the classical electrical thermal conductivity is included, and NND difference scheme is used. The linear growth rates obtained from the simulation agree with the Takabe formula. The ampli- tude distribution of the density perturbation at the ablation front is obtained for the linear growth case. The non-linear characteristics of Rayleigh-Taylor instable perturbations are analyzed and the numerical results show that the amplitude distributions of the compulsive harmonics are very different from that of the fundamental perturbation. The characteristics of the amplitude distributions of the harmonics and their fast growth explain why spikes occur at the ablation front. The numerical results also show that non-linear effects have relations with the phase differences of double mode initial perturbations, and different phase differences lead to varied spikes.

关键词： Inertial confinement fusion Rayleigh-Taylorinstability Non-linear characteristics Direct numerical simulation

Temporal modulation brings metamaterials into new era

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Light(science & Applications) 2022年第7期11卷 1327-1328页

作者： Luqi Yuan shanhui fan state Key Laboratory of Advanced Optical Communication systems and Networks School of Physics and AstronomyShanghai Jiao Tong University200240 ShanghaiChina Department of Electrical Engineering Stanford UniversityStanfordCA 94305USA

Temporal modulations in photonics bring many exotic optical phenomena in the time dimension while metamaterials provide powerful ways in manipulating light in the spatial *** authors envision the connection,Floquet Me... 详细信息

关键词： Metamaterials photonics dimension

statistical Modification Analysis of Helical Planetary Gears based on Response surface Method and Monte Carlo simulation

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Chinese Journal of Mechanical Engineering 2015年第6期28卷 1194-1203页

作者： ZHANG Jun GUO fan school of Mechanical Engineering Anhui University of Technology

Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random errors on gear modification effects. In order to investigate the uncertainties of tooth modification amount variations on system＇s dynamic behaviors of a helical planetary gears, an analytical dynamic model including tooth modification parameters is proposed to carry out a deterministic analysis on the dynamics of a helical planetary gear. The dynamic meshing forces as well as the dynamic transmission errors of the sun-planet 1 gear pair with and without tooth modifications are computed and compared to show the effectiveness of tooth modifications on gear dynamics enhancement. By using response surface method, a fitted regression model for the dynamic transmission error（DTE） fluctuations is established to quantify the relationship between modification amounts and DTE fluctuations. By shifting the inevitable random errors arousing from manufacturing and installing process to tooth modification amount variations, a statistical tooth modification model is developed and a methodology combining Monte Carlo simulation and response surface method is presented for uncertainty analysis of tooth modifications. The uncertainly analysis reveals that the system＇s dynamic behaviors do not obey the normal distribution rule even though the design variables are normally distributed. In addition, a deterministic modification amount will not definitely achieve an optimal result for both static and dynamic transmission error fluctuation reduction simultaneously.

关键词： tooth modification helical planetary gears response surface method Monte Carlo simulation

Evasion strategies of a three-player lifeline game

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science China(Information sciences) 2018年第11期61卷 144-154页

作者： fan ZHANG Wenzhong ZHA school of Automation Beijing Institute of Technology state Key Laboratory of Intelligent Control and Decision of Complex system Information science Academy China Electronics Technology Group Corporation

This study examines a multi-player pursuit-evasion game, more specifically, a three-player lifeline game in a planar environment, where a single evader is tasked with reaching a lifeline prior to capture. A decomposition method based on an explicit policy is proposed to address the game qualitatively from two main aspects:(1) the evader’s position distribution to guarantee winning the game(i.e., the escape zone),which is based on the premise of knowing the pursuers’ positions initially, and(2) evasion strategies in the escape zone. First, this study decomposes the three-player lifeline game into two two-player sub-games and obtains an analytic expression of the escape zone by constructing a barrier, which is an integration of the solutions of two sub-games. This study then explicitly partitions the escape zone into several regions and derives an evasion strategy for each region. In particular, this study provides a resultant force method for the evader to balance the active goal of reaching the lifeline and the passive goal of avoiding capture. Finally,some examples from a lifeline game involving more than one pursuer are used to verify the effectiveness and scalability of the evasion strategies.

关键词： lifeline game three-player pursuit-evasion game barrier evasion strategy game of kind

The first confirmed gravitational wave detection in LIGO's second observational run

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science China(Physics,Mechanics & Astronomy) 2017年第12期60卷 74-79页

作者： Jin Li XiLong fan College of Physics Chongqing University school of Physics and Electronics Information Hubei University of Education

In this article,we describe the results concerning the third coincident signal GW170104 from the coalescence of binary black holes（BBHs）during the second observation run（O2）.The result was obtained from the LIGO scientific Collaboration and the Virgo *** the first and second gravitational waves（GWs）detections in the first observation run（O1）[1],recently LIGO has observed a third coincident signal GW170104 from the coalescence of BBHs

关键词： gravitational observational waveform concerning aligned template astronomy Bayesian instrumental Gabor

A Review about Thermal Comfort in Aircraft

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Journal of Thermal science 2019年第2期28卷 169-183页

作者： fan Juli ZHOU Qiongyao Nanjing University of Aeronautics and Astronautics

Thermal comfort is an important factor which affects both work efficiency and life quality. On the basis of satisfying the normal life of the crew and reliable work of equipment, the thermal comfort is increasingly pursued through the design of the environmental control system of modern craft. Thus, a comprehensive survey of the thermal comfort in the cockpit is carried out. First of all, factors affecting the thermal comfort in aircraft cabin are summarized, including low relative humidity, mean radiant temperature, colored light, human metabolic rate and gender, among which the first three factors are environmental factors and the other two are human factors. Although noise is not a factor affecting thermal comfort, it is an important factor in the overall satisfaction of the aircraft cabin environment. Then the thermal comfort prediction models are introduced, including thermal comfort models suitable for steady state uniform environment and thermal comfort models suitable for transient non-uniform environment. Then the limitations of the typical thermal comfort models applied to aircraft are discussed. since the concept of thermal adaptation has been gradually accepted in recent years, many field studies on thermal adaptation have been carried out. Therefore, the adaptive thermal comfort models are summarized and analyzed systematically in this paper. At present, mixing ventilation(MV) system is widely used in most commercial aircraft. However, the air quality under the MV system is very poor, and contaminants cannot be effectively eliminated. so a noticeable shift is the design of ventilation system for cabin drawing lessons from the surface buildings. Currently, the most interesting question is that whether the traditional mixing ventilation(MV) system in an aircraft can be replaced by or combined with displacement ventilation(DV) system without decreasing thermal comfort. A reduction of energy consumption is a valuable gain. Additionally, various seat persona

关键词： aircraft thermal comfort energy efficient ventilation system numerical simulation

Influence of Fabrication Parameters on the Phase Formation and Dielectric Properties of CaCu_3Ti_4O_(12 )Ceramics

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Journal of Materials science & Technology 2012年第10期28卷 920-926页

作者： Qian Zheng Huiqing fan state Key Laboratory of solidification Processing School of Materials Science and EngineeringNorthwestern Polytech-nical UniversityXi'an 710072China

The giant dielectric permittivity materials CaCu3Ti4012 （CCTO） were synthesized by conventional solid-state reaction techniques. X-ray diffraction and Raman scattering for the powder indicate that the powder calcined at 950 ℃ for 12 h has been completely transformed into the purer CCTO phase. Furthermore, the morphology and size of the grains of the ceramics sintered at 1090 ℃ in the dwell time range from 0 to 26 h were observed by scanning electron microscopy （sEM）. Dielectric properties of the polycrystalline CCTO ceramics were characterized in a broad frequency range （100 Hz-1 MHz） and at a temperature ranged from 300 to 500 K. The longer sintering time may lead to more defect structures and the enhanced conductivity, also leads to substantial improvements in permittivity. Grain size and density differences were not large enough to account for the enhancement in dielectric permittivity. Based on the observations, it is believed that the primary factor affecting dielectric behavior is the development of internal defects. The CCTO ceramics sintered at 1090 ℃ for 15 h exhibit lower dielectric loss （-0.05） near room temperature, and the dielectric relaxation behavior above 1 kHz was observed to follow the Arrhenius law. The activation energy （Ea） of 0.65 eV indicates that the doubly ionized oxygen vacancies in the grain boundaries are responsible for the dielectric relaxation of the CCTO ceramics.

关键词： Microstructure Dielectric properties Impedance spectroscopy Relaxation

New fundamental quantum mechanical operator-ordering identities for the coordinate and momentum operators

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science China(Physics,Mechanics & Astronomy) 2012年第5期55卷 762-766页

作者： fan HongYi Department of Physics Shanghai Jiao Tong UniversityShanghai 200030China Department of Material science and Engineering University of Science and Technology of ChinaHefei 230026China

In quantum mechanics theory one of the basic operator orderings is Q-P and P-Q ordering,where Q and P are the coordinate operator and the momentum operator,*** derive some new fundamental operator identities about their mutual *** technique of integration within Q-P ordering and P-Q ordering is *** Q-P ordered and P-Q ordered formulas of the Wigner operator are also deduced which makes arranging the operators in either Q-P or P-Q ordering much more convenient.

关键词： Q-ordering and B-ordering IWOP technique operator-ordering identities Wigner operator