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一种新的语音信号共振峰提取的算法 被引量:6
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作者 何峰 陈晓清 +1 位作者 李国锁 林嘉宇 《信号处理》 CSCD 北大核心 2007年第4期618-621,共4页
本文提出了一种新的语音信号共振峰的提取方法。在LPC幅度谱上搜寻最大的极大值点所对应的频率,并将它作为构成声道参数的某一谐振腔所对应的共轭复根的角度,再通过LPC系数的相—频特性的一次导数和三次导数相结合的方法求出这对共轭复... 本文提出了一种新的语音信号共振峰的提取方法。在LPC幅度谱上搜寻最大的极大值点所对应的频率,并将它作为构成声道参数的某一谐振腔所对应的共轭复根的角度,再通过LPC系数的相—频特性的一次导数和三次导数相结合的方法求出这对共轭复根的幅度,从而确定了该谐振腔,也就得到了该谐振腔的共振峰。然后,用LPC的多项式对该谐振腔所对应的多项式做多项式除法,得到新的LPC系数,接着重复前面的步骤,可以较好地求出在LPC谱中对应幅度最大的两个共振峰。 展开更多
关键词 LPC 共振峰 相—特性 谐振腔
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Regulation of Nitrogen on Potato under NaCl Stress 被引量:1
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作者 张瑞玖 陈有君 +3 位作者 蒙美莲 郦海龙 周长艳 冯琰 《Agricultural Science & Technology》 CAS 2010年第11期65-67,共3页
The effects of nitrogen on physiological and biochemical characteristics of potato cultivar Zihuabai under NaCl stress were studied in culture condition.The results show that,under NaCl stress,the contents of proline,... The effects of nitrogen on physiological and biochemical characteristics of potato cultivar Zihuabai under NaCl stress were studied in culture condition.The results show that,under NaCl stress,the contents of proline,chlorophyll and protein and root system vitality first increase and then decrease with the increase of nitrogen level,and reach the top under 4.17 mmol/L NH4NO3 level.Wherein,the contents of chlorophyll,protein and root system vitality are respectively 69.88%,13.07% and 59.29% higher than that of the control under 4.17 mmol/L NH4NO3 level;the activities of superoxide dismutase(SOD)and peroxidase(POD)increase generally under NaCl stress with the increase of nitrogen level,and reach the peaks [111.83 U/g and 25.467 U/(g·min)],which are 37.73% and 35.46% higher than that of control,at 6.25 mmol/L NH4NO3 level. 展开更多
关键词 POTATO NaCl stress Nitrogen level Physiological and biochemical characteristics
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Robust CMOS phase frequency detector for high speed and low jitter charge pump PLL
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作者 周建政 王志功 《Journal of Southeast University(English Edition)》 EI CAS 2008年第1期15-19,共5页
In order to improve the performance of the existing phase frequency detectors (PFDs), a systematical analysis of the existing PFDs is presented. Based on the circuit architecture, both classifications and comparison... In order to improve the performance of the existing phase frequency detectors (PFDs), a systematical analysis of the existing PFDs is presented. Based on the circuit architecture, both classifications and comparisons are made. A new robust CMOS phase frequency detector for a high speed and low jitter charge pump phrase-locked loop (PLL) is designed. The proposed PFD consists of two rising-edge triggered dynamic D flip-flops, two positive-edge detectors and delaying units and two OR gates. It adopts two reset mechanisms to avoid the LIP and DN signals to be logic-1 simultaneously. Thus, any current mismatch of the charge pump circuit will not worsen the performance of the PLL. Furthermore, it has hardly any dead-zone phenomenon in phase characteristic. Simulations with ADS are performed based on a TSMC 0. 18-μm CMOS process with a 1.8-V supply voltage. According to the theoretical analyses and simulation results, the proposed PFD shows a satisfactory performance with a high operation frequency (≈ 1 GHz), a wide phase-detection range [ ± 2π], a near zero dead-zone ( 〈 0. 1 ps), high reliability, low phase jitter, low power consumption ( ≈100 μW) and small circuit complexity. 展开更多
关键词 phase frequency detectors DEAD-ZONE blind-zone phase characteristic frequency characteristic
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Genetic Relationships Among Soluble Carbohydrates, Anthocyanins and Growth Characteristics in Leymus (Gramineae) Detected with Molecular Markers 被引量:3
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作者 胡赞民 Steven R. LARSON +1 位作者 Thomas A. JONES Richard R-C. WANG 《Acta Botanica Sinica》 CSCD 2002年第10期1173-1181,共9页
Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization ... Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization requirement, growth, and soluble carbohydrate accumulations of the winter-annual Triticeae species. Two hundred and four unmapped AFLP markers and genome-specific DNA markers genetically linked to the vrn-1 gene were used to detect QTL controlling soluble carbohydrate accumulations, anthocyanin coloration and growth characteristics in a segregating population derived from open pollinated Leymus cinereus x L. triticoides hybrids. These perennial Triticeae grasses are distinguished by adaptation and growth habit. As expected, positive trait correlations and pleiotropic gene effects were detected for soluble carbohydrate accumulations and anthocyanin coloration. Likewise, positive trait correlations and pleiotropic gene effects were detected for tillering, leaf development, leaf growth, regrowth and rhizome spread. However, soluble carbohydrate accumulations were not associated with attenuated growth. In fact, several DNA marker alleles, including one near vrn-Ns1, had positive effects on soluble leaf carbohydrate concentrations and low temperature growth. The corresponding DNA marker near vrn-Ns1 had more specific effects on tillering. We speculate that vrn-1 exerts quantitative effects on low-temperature soluble leaf carbohydrate accumulations and growth habit of the perennial Leymus. However, a number of other DNA markers displayed highly significant effects on soluble carbohydrate accumulations and various growth characteristics. Findings indicate that anthocyanin coloration may be a useful phenotypic marker for soluble carbohydrate accumulation. Although variation for soluble carbohydrates was not associated with attenuated growth in this population, this trait was under genetic control. 展开更多
关键词 LEYMUS molecular markers genetic relationship
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Comparison Between Three-Valley Model and Full Band Model in Monte Carlo Simulation of Bulk Wurtzite GaN 被引量:1
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作者 郭宝增 王永青 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第2期113-119,共7页
The Monte Carlo simulators with the three valley model and the full band Monte Carlo model are used to explore electron transport in bulk wurtzite gallium nitride (GaN).Comparison of the results based on the two mode... The Monte Carlo simulators with the three valley model and the full band Monte Carlo model are used to explore electron transport in bulk wurtzite gallium nitride (GaN).Comparison of the results based on the two models is made.The results based on both models are basically the same at the lower field region,but exhibit some differences at the higher field region.The electron average energy exhibits obvious difference at the high field region between the two models.This difference further causes several other differences of GaN properties,such as the drift velocity versus field characteristics,the repopulation.Because of the complicated energy band structures at the high energy region for wurtzite GaN,the analytical band structures in the three valley model can not cover all properties of the band structures of wurtzite GaN,so the results based on the full band Monte Carlo model should be more exact. 展开更多
关键词 Monte Carlo simulation wurtzite GaN transport properties band structures
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Experimental investigation on heat transfer characteristics of a new radiant floor system with phase change material 被引量:1
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作者 夏燚 张小松 《Journal of Southeast University(English Edition)》 EI CAS 2015年第4期496-500,共5页
In order to improve the heat transfer characteristics of the traditional phase change material(PCM) floor, a new double-layer radiant floor system with PCM is proposed, which can store thermal or cold energy in the ... In order to improve the heat transfer characteristics of the traditional phase change material(PCM) floor, a new double-layer radiant floor system with PCM is proposed, which can store thermal or cold energy in the off-peak period and use them in the peak period. An experimental setup was developed to study the heat transfer characteristics of the new system under both cooling and heating modes. The experimental results show that the double-layer radiant floor system with PCM can meet both the cold and thermal requirements of users. Moreover, with the same duration of the thermal energy storage process, the increase of water temperature supplied to the system can improve the heat transfer characteristics of the system but lead to the discomfort of users. On the other hand, if the air temperature at the end of the thermal energy storage process is the same under different conditions, the increase of supplied water temperature will decrease the thermal energy storage time and ensure the comfort of users. 展开更多
关键词 ENERGY-SAVING radiant floor phase changematerial DOUBLE-LAYER heat transfer characteristics
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Biological Characteristics of Biosurfactantproducing Petroleum-degrader Bacterium Bacillus BS-8
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作者 常慧萍 邢文会 +3 位作者 夏铁骑 付瑞敏 陶令霞 张红 《Agricultural Science & Technology》 CAS 2016年第1期1-3,18,共4页
The growth characteristics of petroleum-degrader BS-8(Bacillus sp.) and the factors influencing its biosurfactant production were tested; the biosurfactant releasing mode of BS-8 was speculated by measuring OD600, s... The growth characteristics of petroleum-degrader BS-8(Bacillus sp.) and the factors influencing its biosurfactant production were tested; the biosurfactant releasing mode of BS-8 was speculated by measuring OD600, surface tension and oil displacement of fermentation broth; and the effects of carbon source, nitrogen source, temperature, p H, and Na Cl concentration on biosurfactant production by BS-8 were observed in this study. The results showed that the biosurfactant releasing mode of BS-8 was growth-correlated, the surface tension of BS-8 fermentation broth declined with the total bacteria increasing, and the oil displacement was positive correlated with biosurfactant content in fermentation broth; and the optimal culture conditions for effective biosurfactant production included: glucose as carbon source,yeast extract as nitrogen source, Na Cl concentration of 2%, p H of 7.0 and temperature at 30 ℃. 展开更多
关键词 BIOSURFACTANT Petroleum-degrader BS-8 Growth-correlated Biological characteristic
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Seed Morphology and Seedling Variation of Four Ornamental Lupin Pedigrees
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作者 高柱 王小玲 +3 位作者 刘腾云 高松金 喻琼 余发新 《Agricultural Science & Technology》 CAS 2015年第1期57-62,67,共7页
[Objective] This study was conducted to reveal seed characteristics, variation and their effects on seedling growth of ornamental lupins. [Method] The phenotypic characteristics and germination rate of the seeds of fo... [Objective] This study was conducted to reveal seed characteristics, variation and their effects on seedling growth of ornamental lupins. [Method] The phenotypic characteristics and germination rate of the seeds of four excellent lupin pedigrees were measured, and then their correlations with seeding growth were analyzed. [Result] There were abundant variations among the four ornamental lupin pedigrees. Pink seeds had the largest volume and red seeds had the largest 1 000seed weight. The variation coefficients for the seed morphological traits among the four pedigrees ranged from 2.97% to 14.34%. Seed specific weight and 1 000-seed weight could be used as important indicators for selection in breeding because of their higher variability. Seed weight variation of ornamental lupin was mainly depen- dent on seed width variation. There was small variation in seed length. The seeds of the four ornamental lupin pedigrees started to germinate one day after sowing, and the germination period was 5 d. Germination rate coefficient and germination index of pink and red seeds were higher than those of blue seeds, but blue seeds had the largest germination rate. 1 000-seed weight shared significantly positive correlations with seed germination rate, germination potential and seedling retention rate. Round and large seeds had some advantages in germination. Full seeds had higher germination rate and speed, and seedling retention rate. There was a significant relationship between seed length-width ratio and the number of leaflets of seedlings. [Conclusion] The results provided references for the evaluation of seed phenotypic diversity and breeding research of ornamental lupins. 展开更多
关键词 Ornamental lupin PEDIGREE Seed morphology Seedling variation Correlation analysis
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HIERARCHIC GREY QUASI-PREFERRED ANALYSIS MODEL AND ITS APPLICATION
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作者 李炳军 刘思峰 任盈盈 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第1期78-83,共6页
The grey quasi-preferred analysis (GQPA) is one of important methods for realizing system analysis to conquer the limitations of the existing GQPA model, without any considerations to the difference of the different b... The grey quasi-preferred analysis (GQPA) is one of important methods for realizing system analysis to conquer the limitations of the existing GQPA model, without any considerations to the difference of the different behavioral factor′s importance. It could not be used to analyze the complex system with multi-hierarchy correlation factors, the weighted synthetic method for calculating abstract incidence degrees between the system beha-vioral characteristics and correlative factors in different hierarchies is given out,and the hierarchic grey quasi-preferred analysis (HGQPA) model is established. The effectiveness of the HGQPA model is tested by the scientific-technical system of Jiangsu Province. The depth and the range of the application of GQPA are developed, and the HGQPA model is regarded as a new approach to systemically analyze the complex systems with multi-hierarchy correlation factors. 展开更多
关键词 multi-hierarchy quasi-preferred analysis MODEL grey system
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Fabrication of Cu_2O@Cu_2O core-shell nanoparticles and conversion to Cu_2O@Cu core-shell nanoparticles in solution 被引量:2
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作者 杨爱玲 李顺嫔 +3 位作者 王玉金 王乐乐 包西昌 杨仁强 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第11期3643-3650,共8页
Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive a... Cu2O@Cu2O core-shell nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Cu2O@Cu2O NPs were easily converted to Cu2O@Cu NPs with the help of polyvinylpyrrolidine (PVP) and excessive ascorbic acid (AA) in air at room temperature, which was an interesting phenomenon. The features of the two kinds of NPs were characterized by XRD, TEM and extinction spectra. Cu2O@Cu NPs with different shell thicknesses showed wide tunable optical properties for the localized surface plasmon (LSP) in metallic Cu. But Cu2O@Cu2O NPs did not indicate this feature. FTIR results reveal that Cu+ ions on the surface of Cu2O shell coordinate with N and O atoms in PVP and are further reduced to metallic Cu by excessive AA and then form a nucleation site on the surface of Cu2O nanocrystalline. PVP binds onto different sites to proceed with the reduction utill all the Cu sources in Cu2O shell are completely assumed. 展开更多
关键词 Cu2O@Cu2O core-shell nanoparticles Cu2O@Cu core-shell nanoparticles solution phase strategy reducing agent tunable optical properties polyvinylpyrrolidine
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Measurement of spatiotemporal characteristics of femtosecond laser pulses by a modified single-shot autocorrelation
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作者 邓杨保 邓曙光 +3 位作者 熊翠秀 张光富 田野 沈连丰 《Journal of Southeast University(English Edition)》 EI CAS 2014年第4期411-415,共5页
To overcome the shortcomings of the single-shot autocorrelation SSA where only one pulse width is obtained when the SSA is applied to measure the pulse width of ultrashort laser pulses a modified SSA for measuring the... To overcome the shortcomings of the single-shot autocorrelation SSA where only one pulse width is obtained when the SSA is applied to measure the pulse width of ultrashort laser pulses a modified SSA for measuring the spatiotemporal characteristics of ultrashort laser pulses at different spatial positions is proposed. The spatiotemporal characteristics of femtosecond laser pulses output from the Ti sapphire regenerative amplifier system are experimentally measured by the proposed method. It was found that the complex spatial characteristics are measured accurately.The pulse widths at different spatial positions are various which obey the Gaussian distribution.The pulse width at the same spatial position becomes narrow with the increase in input average power when femtosecond laser pulses pass through a carbon disulfide CS2 nonlinear medium.The experimental results verify that the proposed method is valid for measuring the spatiotemporal characteristics of ultrashort laser pulses at different spatial positions. 展开更多
关键词 spatiotemporal characteristics modified single-shot autocorrelation femtosecond laser pulses ultrafast laser technology
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Comethylation of p16 and MGMT genes in colorectal carcinoma:Correlation with clinicopathological features and prognostic value 被引量:10
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作者 Koviljka Krtolica Milena Krajnovic +3 位作者 Slavica Usaj-Knezevic Dragan Babic Dusan Jovanovic Bogomir Dimitrijevic 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第8期1187-1194,共8页
AIM: To investigate the significance of p16 and O6- methylguanine-DNA methyltransferase (MGMT) genes promoter hypermethylation and K-ras mutations on colorectal tumorigenesis and progression. METHODS: p16 and MGMT met... AIM: To investigate the significance of p16 and O6- methylguanine-DNA methyltransferase (MGMT) genes promoter hypermethylation and K-ras mutations on colorectal tumorigenesis and progression. METHODS: p16 and MGMT methylation status was examined on 47 tumor samples, and K-ras mutational status was examined on 85 tumor samples. For methylation analysis, a methylation specific PCR (MS-PCR) method was used. RESULTS: p16 and MGMT promoter methylation was found in 51% (24/47) and 43% (20/47) of CRCs, respectively, and the K-ras mutation was found in 44% (37/85) of CRCs. Comethylation of p16 and MGMT genes was significantly associated with lower aggressiveness of the disease within a two-year period of observation. Only 27% of patients with simultaneous p 16 and MGMT methylation showed the detectible occurrence of metastasis and/or death, compared to 67% of patients without double methylation or with no methylation (3/11 vs 22/33, P < 0.05, χ2-test). In addition, p16 and MGMT comethylation showed a trend toward an association with longer survival in patients with CRCs (35.5 ± 6.0 mo vs 23.1 ± 3.2 mo, P = 0.072, Log-rank test). Progression of the disease within a two-year period was observed in 66% of patients carrying the K-ras mutation, compared to only 19% of patients with wild type K-ras (29/44 vs 7/37, P < 0.001, χ2-test). The presence of the K-ras mutation significantly correlated to shortened overall survival (20.0 ± 1.9 mo vs 37.0 ± 1.8 mo, P < 0.001, Log-rank test). The comethylation of p16 and MGMT genes was significantly associated with lower aggressiveness of the disease even when K-ras mutations were included in the analysis as an independent variable. CONCLUSION: Our data suggest that comethylation of promoters of p 16 and MGMT genes could have a prognostic value in patients with CRC. Specifically, concurrent methylation of both genes correlates with better prognosis. 展开更多
关键词 Colorectal carcinoma DNA methylation P16 MGMT K-ras mutation
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First principles study of structural, electronic and mechanical properties of transition metal hydrides(TMH, TM=Mo,Tc, Ru) 被引量:3
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作者 G. SUDHA PRIYANGA A.T.ASVINI MEENAATCI +1 位作者 R. RAJESWARA PALANICHAMY K.IYAKUTTI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第9期2700-2707,共8页
The structural, electronic and mechanical properties of transition metal hydrides (TMH, TM=Mo, Tc, Ru) are investigated by means of first principles calculation based on density fimctional theory with generalized gr... The structural, electronic and mechanical properties of transition metal hydrides (TMH, TM=Mo, Tc, Ru) are investigated by means of first principles calculation based on density fimctional theory with generalized gradient approximation. Among the five crystallographic structures that have been investigated, the cubic phase is found to be more stable than the hexagonal ones. A structural phase transition from ZB to WC in Moll, NaC1 to NiAs in TcH and NaCI to ZB to NiAs in RuH is also predicted under high pressure. The calculated elastic constants indicate that all the three hydrides are mechanically stable at ambient pressure. 展开更多
关键词 ab-initio method structural phase transition electronic properties elastic property
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An Experimental Study on the Flow Characteristics of OilWater Two-Phase Flow in Horizontal Straight Pipes 被引量:7
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作者 刘文红 郭烈锦 +1 位作者 吴铁军 张西民 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第5期491-496,共6页
The flow patterns and their transitions of oil-water two-phase flow in horizontal pipes were studied. The experiments were conducted in two kinds of horizontal tubes, made of plexiglas pipe and stainless steel pipe wi... The flow patterns and their transitions of oil-water two-phase flow in horizontal pipes were studied. The experiments were conducted in two kinds of horizontal tubes, made of plexiglas pipe and stainless steel pipe with 40 mm ID respectively. No. 46 mechanical oil and tap water were used as working fluids. The superflcial velocity ranges of oil and water were: 0.04-1.2m·s-1 and 0.04-2.2m·s-1, respectively. The flow patterns were identified by visualization and by transient fluctuation signals of differential pressure drop. The flow patterns were defined according to the relative distribution of oil and water phases in the pipes. Flow pattern maps were obtained for both pipelines. In addition, semi-theoretical transition criteria for the flow patterns were proposed, and the proposed transitional criteria are in reasonable agreement with available data in liquid-liquid systems. 展开更多
关键词 oil-water two-phase flow horizontal pipe flow pattern transition criterion
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Guaranteeing Wireless Communication Secrecy via a WFRFT-Based Cooperative System 被引量:18
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作者 Fang Xiaojie Sha Xuejun Mei Lin 《China Communications》 SCIE CSCD 2015年第9期76-82,共7页
In this paper, a weighted fractional Fourier transform(WFRFT) based cooperative overlay system, aiming to guarantee physical layer(PHY) security, is proposed. The paper elaborates how WFRFT and physical layer properti... In this paper, a weighted fractional Fourier transform(WFRFT) based cooperative overlay system, aiming to guarantee physical layer(PHY) security, is proposed. The paper elaborates how WFRFT and physical layer properties of the wireless medium are collaborated to guarantee the secrecy of wireless transmissions. In the proposed system, WFRFT is first preform on the secret data, such that the transmitted signal is distorted and can only be neutralized by inverse-WFRFT with the same parameter. And then two streams of the transformed sequences that bearing different messages are cooperatively and simultaneously transmitted to two legitimate receivers via a beamforming-liked method, respectively. In general, both the rapid spatial decorrelation property and the inherent security features of WFRFT are leveraged, such that only the eavesdropper's is degraded, and hence, the wireless communication secrecy is reliably guaranteed. Numerical simulations are conducted to evaluate the performance of the proposed system in terms of the average bit error rate and the secrecy capacity. 展开更多
关键词 weighted fractional Fourier trans-form(WFRFT) physical layer(PHY) security secrecy capacity
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Local Gas Phase Flow Characteristics of a Gas-Liquid-Solid Three-Phase Reversed Flow Jet Loop Reactor 被引量:2
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作者 闻建平 周怀 陈云琳 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第1期119-122,共4页
The local gas-phase flow characteristics such as local gas holdup(εg), local bubble velocity (V_b) and local bubble mean diameter(d_b) at a specified point in a gas-liquid-solid three-phase reversedflow jet loop reac... The local gas-phase flow characteristics such as local gas holdup(εg), local bubble velocity (V_b) and local bubble mean diameter(d_b) at a specified point in a gas-liquid-solid three-phase reversedflow jet loop reactor was experimentally investigated by a five-pointconductivity probe. The effects of gas jet flow rate, liquid jet flowrate, solid loading, nozzle diameter and axial position on the localεg, V_b and d_b profiles were discussed. The presence of solids atlow solid concentrations not only increased the local εg and V_b,but also decreased the local d_b. The optimum solid loading for themaximum local εg and V_b together with the minimum local d_b was0.16×10^-3 m^3, corresponding to a solid volume fraction ε_S=2.5/100. 展开更多
关键词 local gas holdup local bubble velocity local bubble mean diameter gas-liquid-solid three-phase
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Esophageal granular cell tumors:Report of 9 cases and a literature review 被引量:6
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作者 Guo-Qiang Xu Hong-Tan Chen +1 位作者 Cheng-Fu Xu Xiao-Dong Teng 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第47期7118-7121,共4页
Esophageal granular cell tumors(GCTs) are rare tumors of the esophagus.We evaluated the clinical and pathologic features of 9 esophageal GCT patients(5 men and 4 women) from our institute and reviewed the related dise... Esophageal granular cell tumors(GCTs) are rare tumors of the esophagus.We evaluated the clinical and pathologic features of 9 esophageal GCT patients(5 men and 4 women) from our institute and reviewed the related disease literature.Patient age ranged from 25 to 53 years(mean:41 years).All the patients were asymptomatic or presented with non-specific symptoms.Most GCTs occurred in the distal esophagus and were less than 6 mm in diameter.Computational analysis showed that the average gray-scale endoscopic ultrasound images of esophageal GCTs were greater than that of esophageal leiomyomas.Eight patients were treated by endoscopic resection,and 1 patient underwent surgical excision.No post-therapy recurrence or metastasis developed during follow-up(mean:36.4 mo,range:1-72 mo). 展开更多
关键词 Esophageal granular cell tumor Endoscopic ultrasonography Computer images analysis
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An Experimental Study on Alkaline/Surfactant/Polymer Flooding Systems Using Natural Mixed Carboxylate 被引量:2
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作者 牟建海 李干佐 李英 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2001年第2期162-166,共5页
Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding sy... Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil recovery is increased by about 25.2% and 26.8% original oil in place, respectively. 展开更多
关键词 alkaline/surfactant/polymer flooding system natural mixed carboxylate interfacial tension phase behavior orthogonal-test-design
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Correlation Analysis of X-Band Sea Clutter in Complex Domain 被引量:1
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作者 CHENG Xiaolong JI Tingting +1 位作者 WANG Guoyu JI Guangrong 《Journal of Ocean University of China》 SCIE CAS 2016年第4期613-618,共6页
The correlation analysis of sea clutter data in a complex domain is conducted in this study. Specific to X-band sea clutter, the statistical characteristics of the complex correlation, particularly the phase character... The correlation analysis of sea clutter data in a complex domain is conducted in this study. Specific to X-band sea clutter, the statistical characteristics of the complex correlation, particularly the phase characteristics which are closely related to the phase difference of the sea clutter and the Doppler properties, are analyzed in detail based on the experimental data, recorded by the Mc Master University IPIX radar in 1993. That the phase term of the complex correlation presents linear change means that there exists the linearity of phase differences between different time intervals in the X-band sea clutter. This investigation explores the regularities about the effect of wind on the complex correlation with similar patterns for different polarization modes. The regularities indicate that the wind direction can be inferred from the distribution pattern of the complex correlation. Moreover, a model describing the relationships between the statistics of the complex correlation and wind parameters is proposed. The application for target detection based on the differences of characteristics of complex correlations between the sea clutter and the target are also investigated and the proposed features have been confirmed. The principle of the method is fundamental for broader future applications. 展开更多
关键词 clutter Correlation Domain describing fitting patch scatter correspondence descriptor normalized
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Multi-scale Chaotic Analysis of the Characteristics of Gas-Liquid Two-phase Flow Patterns 被引量:5
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作者 李洪伟 周云龙 +1 位作者 孙斌 杨悦 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第5期880-888,共9页
Using the high-speed camera the time sequences of the classical flow patterns of horizontal gas-liquid pipe flow are recorded, from which the average gray-scale values of single-frame images are extracted. Thus obtain... Using the high-speed camera the time sequences of the classical flow patterns of horizontal gas-liquid pipe flow are recorded, from which the average gray-scale values of single-frame images are extracted. Thus obtained gray-scale time series is decomposed by the Empirical Mode Decomposition (EMD) method, the various scales of the signals are processed by Hurst exponent method, and then the dual-fractal characteristics are obtained. The scattered bubble and the bubble cluster theories are applied to the evolution analysis of two-phase flow patterns. At the same time the various signals are checked in the chaotic recursion chart by which the two typical characteristics (diagonal average length and Shannon entropy) are obtained. Resulting term of these properties, the dynamic characteristics of gas-liquid two-phase flow patterns are quantitatively analyzed. The results show that the evolution paths of gas-liquid two-phase flow patterns can be well characterized by the integrated analysis on the basis of the gray-scale time series of flowing images from EMD, Hurst exponents and Recurrence Plot (RP). In the middle frequency section (2nd, 3rd, 4th scales), three flow patterns decomposed by the EMD exhibit dual fractal characteristics which represent the dynamic features of bubble cluster, single bubble, slug bubble and scattered bubble. According to the change of diagonal average lengths and recursive Shannon entropy characteristic value, the structure deterministic of the slug flow is better than the other two patterns. After the decomposition by EMD the slug flow and the mist flow in the high frequency section have obvious peaks. Anyway, it is an effective way to understand and characterize the dynamic characteristics of two-phase flow patterns using the multi-scale non-linear analysis method based on image gray-scale fluctuation signals. 展开更多
关键词 gas-liquid two-phase flow gray-scale time series empirical mode decomposition Hurst exponent chaotic recurrence plot
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