Table of Content

20 January 2001, Volume 37 Issue 1

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Error Analysis of Doppler Radar Expanded VAD Technique

BAI Jie,ZHOU Xiaobo,WANG Likun,TAO Zuyu

2001, 37(1):  48-54. 

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VAD (Velocity-Azimuth Display) technique can retrieve larger scale wind and divergence efficiently. Triple VAD(TVAD) and half VAD technique are an extension of VAD technique, they can get the large-scale mean wind information of different region in radar scan area. In this paper, the error analytic formula of expanded VAD technique (TVAD and half VAD) against VAD technique is obtained in theory. It is proved that harmonic analytic method can be used to calculate the first harmonic coefficient from half circle data accurately and from triple circle data approximately by error theory and simulating test and observed radar data fitting test. So the large-scale winds retrieved by half VAD technique have the same precision as the wind retrieved by VAD technique, and the large-scale winds retrieved by TVAD technique have some error. The error of the large-scale wind retrieved by TVAD technique has some relationship to initial phase of the fitting harmonic curve. The error of wind direction from TVAD technique is 0～20°, relative error of wind speed is 0～0.4. Simulated test of ideal harmonic dispersed data indicates that the average error of wind direction retrieved by TVAD is 16°, relative error of wind speed is 0.27, it is close to the error of conventional wind observation. The fitting test of Doppler velocity-azimuth profile illustrates that the fitting harmonic curve of half VAD technique and TVAD technique can give the characteristic of the large-scale wind field in the calculated area.

A Scheme of Error-detecting Codes

QIU Weisheng

2001, 37(1):  1-5. 

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It is presented that a scheme of error-detecting codes, give its computational methods, find probabilities detected of each type of error. In particular, a set of check character systems of 《National Standard of People's Republic of China: Data Processing-Check Character Systems》 and 《International Standard ISO 7064》can be derived from this scheme.

Weighted Approximation on Szász-Mirakjan Operators

LI Cuixiang,ZHAO Yang

2001, 37(1):  6-11. 

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It is introduced that ω_φ²λ(f, t)_w and apply it to study the weighted approximation on Szász operators, and give a pointwise results which expands some previous results.

The Pickands' Estimator of the Negative Extreme-value Index

PENG Zuoxiang,S Nadarajah

2001, 37(1):  12-19. 

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It is proposed that a new estimator of the extreme-value index (when it is negative) that is similar in form to the Pickands' estimator. Its consistency and asymptotic distribution is established.

A Note on the Least Prime in an Arithmetic Progression

MENG Zaizhao

2001, 37(1):  20-22. 

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It is proved that the least prime in an arithmetic progression with difference q(has bounded cubic part) is <<q^4.5.

A Refined Theory of Transversely Isotropic Plates

YIN Huiming,WANG Wei

2001, 37(1):  23-33. 

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In this paper, to counter a flexible beam undergoing large overall motion imA refined plate theory for transversely isotropic materials is derived by using Elliott-Lodge solutions and Lur'e operator method. The two possibilities s₁²≠s₂² and s₁²=s₂² are both considered.

Stability Analysis for a Class of Nonlinear Feedback System

YU Xuegang,HUANG Lin

2001, 37(1):  34-43. 

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Using the integral quadratic constraints (IQC's) methods, the L₂-stability for a class of nonlinear feedback system is studied in this paper. Thus some sufficient and necessary conditions are given. These results are suitable for both time-invariant and time-varying systems. As an application, the general time-varying Lur'e problem is studied too. Then the time-varying circle criterion in the SISO case is given. At the same time, in the MIMO case, a stability criterion is given, which doesn't need the decoupling conditions.

A Theoretical Research of Hall Coefficient in the Normal State of Bi₂Sr₂CaCu₂O_8+δ

ZHANG Shuang,ZHANG Liyuan

2001, 37(1):  44-47. 

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Using the formula of the nearly local pair model, based on the two-component model of high-T_c superconductivity, we have studied temperature-dependent phenomena of Hall coefficient in the normal state of Bi₂Sr₂CaCu₂O_8+δ, and got the results consistent with the experiments. It is argued that the successive deepening of pseudogap with decreasing temperature leads to that Hall coefficient attains to a positive maximum at the temperature a little higher than T_c, and the maximum corresponds about the bottom of pseudogap depth changing with temperature.

The Study of Kinematic Turbulence Parameterization in Meso-scale Numerical Weather Forecast

SUN Aidong,XU Yumao

2001, 37(1):  55-66. 

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The improvement to the turbulence parameterization of meso-scale forecast model MM4 was presented. A turbulent kinematic energy(TKE)parameterization is used all over the forecast time in the whole model region to take the local K-theory's place in the bulk aerodynamic parameterization of the host model MM4, while MM4 with the high-resolution PBL parameterization is used as control forecast. MM4 with different parameterizations was utilized on the forecast of rainstorm on July 17, 1997, and new TKE parameterization introduced a reasonable distribution of turbulent variables. The computational stability is good and the forecast results of different variables are close to or better than those of the control model, Although locations of the strongest rainfall do not show any improvement, the amount of the 24-hour rainfall is larger than that forecasted by the control model. This amount is still not as large as the actual rainfall, but this result shows that the TKE parameterization is encouraging. The application of TKE parameterization readjusts the distribution of eddy viscosity, K_m, and hence improves the model.

The Application of Ultra-long Electromagnetic Wave Remote Sensing to Deep Petroleum Exploration Under Bohai Sea

HOU Guiting,YI Xuelei,QIAN Xianglin,ZHAO Weiming

2001, 37(1):  81-86. 

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On the basis of analysis and comparison between two drills, one in the center of Bohai Sea, another near the west shore of Bohai Sea, ultra-long electromagnetic wave remote sensing can be applied to forecast the interfaces between the different rocks, and help to choose the location of drill and drilling plan. The ultra-long electromagnetic remote sensing also can be applied to general investigation in the prospecting area and organizing the structural map on the basis of the profiles and plane. Based on the analysis of the ultra-long electromagnetic wave curves from Tanggu to Dalian, the geological body to effect the high gravity and magnetic anomalies could be a mafic intrusion. The magma activity provided the heat source to organic maturation in the center of Bohai Sea, so the center of Bohai Sea could be the prospection of deep gas in Bohai Sea.

The Application of CCA in Climatic Analysis and Prediction in Recent Years

HUANG Maoyi,HUANG Jiayou,WANG Yong,TIAN Feng

2001, 37(1):  128-135. 

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The application of CCA(Canonical Correlation Analysis)in climate analysis and prediction in recent years is elaborated. The demonstration is focus on its advantages and disadvantages in theoretical and practical aspects. The study also give the example applied to the summer precipitation forecasting in China.

The Application of CCA in Climatic Analysis and Prediction in Recent Years

HUANG Maoyi,HUANG Jiayou,WANG Yong,TIAN Feng

2001, 37(1):  128-135. 

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The application of CCA(Canonical Correlation Analysis)in climate analysis and prediction in recent years is elaborated. The demonstration is focus on its advantages and disadvantages in theoretical and practical aspects. The study also give the example applied to the summer precipitation forecasting in China.

Studies of Extension-compression Tectonic Dynamic Setting in Sichuan Basin

LI Zhongquan,PAN Mao,XIAO Deming,CHEN Gengsheng,LU Zhongkan,YING Danlin

2001, 37(1):  87-93. 

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Viewing from the global tectonics, the authors dynamically described the dialectical relationships between extensions and compressions in time special 4-D, and pointed out the different tectonic deformation systems corresponding to different tectonic dynamical environments. Considering the geological evolution of Sichuan Basin, from nine aspects, the authors proved that the tectonic dynamical environments of Sichuan Basin, after its formation, has experienced the early extension, middle transition and late compression environments. Correspondingly, as the paper suggests, a considerable attention need to be paid to the comprehensive studies of the early extensional structures, middle inversion structures and the late compression structures of Sichuan Basin when analyzing its tectonics.

Indicator Kriging Study of Multivariate Information in Temporal-spatial Domain

XIAO Bin,PAN Mao,ZHAO Pengda,HOU Jingru

2001, 37(1):  94-98. 

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Based on indicator kriging and the theory of coregionalization in spatial domain, indicator kriging of multivariate information in temporal-spatial domain was discussed. Authors mainly studied second order moment of indicator kriging, indicator cokriging, indicator principal component kriging and order relation in temporal-spatial domain.

Significance of Paleostructure and Paleogeography of Ordovician-Silurian Rock Associations in Northern Xinjiang, China

HE Guoqi,LI Maosong

2001, 37(1):  99-110. 

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Traditional tectonic ideas are that the orogenic belts in the northern Xinjiang were formed mainly in the late Paleozoic. However, new data show that there is almost continuous early Paleozoic orogenic belt surrounding the Junggar Basin. The facts will change the traditional idea which only emphasizes the late Paleozoic orogenesis. According to the new data, authors reconstructed the early Paleozoic geologic evolution of the Northern Xinjiang. The Junggar and adjacent old lands began to breakup in the Sinian period. The ancient ocean between those old lands came up to the biggest size at early Ordovician. The inferential Junggar old land often situated below sea level in the period of cracking and spreading of the old land. The ancient ocean of the Northern Xinjiang began to shrink and the old continental margin became active margin in the late Ordovician. Then, convergence, collision and orogenesis were took place among the Junggar, Yili and Siberia old lands. The late Ordovician and early middle Silurian forearc or back arc foreland basins might develop on the side of earn Junggar old land of the early Paleozoic orogenic belts.

A Review for the Models of Outflow Jet-driving

CAI Kai,WU Yuefang

2001, 37(1):  121-127. 

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Molecular outflows from young stars are important phenomena in star formation Suggestions for their driving mechanisms are various. Several jet-driven models are introduced.According to the domination of two interaction patterns, models are classified as two kinds, and a detailed introduction of each kind are presented. Flnally, some left problems are forwarded.

A Review for the Models of Outflow Jet-driving

CAI Kai,WU Yuefang

2001, 37(1):  121-127. 

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Molecular outflows from young stars are important phenomena in star formation Suggestions for their driving mechanisms are various. Several jet-driven models are introduced. According to the domination of two interaction patterns, models are classified as two kinds, and a detailed introduction of each kind are presented. Flnally, some left problems are forwarded.

Regional Ecological Risk Assessment of Wetland in the Huanghe River Delta

XU Xuegong,LIN Huiping,FU Zaiyi,BU Rencang

2001, 37(1):  111-120. 

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Through the case study of the wetland in the Huanghe River (Yellow River) delta, the concept of regional ecological risk assessment is inquired into, and a set of assessment method was developed. The main process of regional ecological risk assessment includes 5 stages: regional analysis, risk receptor selection, risk sources analysis, exposure and hazard analysis, and integrated risk assessment. Arming at flood, drought, storm tide, petroleum pollution accident and flow breaking in the lower Huanghe River, the probability and distribution of each kind of risk sources are evaluated. The authors bring forward indexes and formulas to measure hazarded degree and risk value of ecosystem. By using remote sensing data, historic record, survey data and by means of geographical information system (GIS), regional ecological risk assessment is finished. On the basis of assessment result, the environmental risk management countermeasure of the Huanghe River delta is advanced.

The Laser Microprobe Dating Drives K-Ar Geochronology into A New Milestone at the End of 20th Century

MU Zhiguo,GAO Yongjun

2001, 37(1):  136-142. 

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K-Ar age dating method is facing a serious challenge to its application due to that both Ar loss and Ar excess are widespread found even though it has been undergoing 50 years. In the latest few years of the 20th century, studies on K-Ar geochronology have been pushing on a new step as a sign of method perfected and precision enhanced. High precision and high resolution ⁴⁰Ar/³⁹Ar dating, can use in both micro-area and a single grain, extends dating limit into the historical realm. Applied range of K-Ar geochronology is getting bigger and bigger due to fine analytical techniques while solved geological problems are getting wider and wider.

The Laser Microprobe Dating Drives K-Ar Geochronology into A New Milestone at the End of 20th Century

MU Zhiguo,GAO Yongjun

2001, 37(1):  136-142. 

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K-Ar age dating method is facing a serious challenge to its application due to that both Ar loss and Ar excess are widespread found even though it has been undergoing 50 years. In the latest few years of the 20th century, studies on K-Ar geochronology have been pushing on a new step as a sign of method perfected and precision enhanced. High precision and high resolution ⁴⁰Ar/³⁹Ar dating, can use in both micro-area and a single grain, extends dating limit into the historical realm. Applied range of K-Ar geochronology is getting bigger and bigger due to fine analytical techniques while solved geological problems are getting wider and wider.

A Study on Speech Recognition for Isolate Words

WU Shuzhen,CHENG Qiansheng

2001, 37(1):  67-70. 

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A speech recognition method is described, that is based on a combination of finite-state vector quantization(FSVQ) and dynamic spectral features. FSVQ is a recallable vector quantization system, which also uses past information for optimizing the code book, and is more effective for speech recognition. The characteristics of a speech signal are represented by time sequences of LPC cepstral coefficients, the dynamic spectral features and log-energy. According to pronunciation feature of Mandarin, the distance values were weighted for the parts of word termination. The experimental results show that the depended speaker speech recognition rate is 98%.

Using FDTD Method to Analyze the EM Scattering of A Coated Object

LI Mingzhi,WANG Changqing,ZHU Xili

2001, 37(1):  71-73. 

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Using FDTD method, the RCS of a missile head coated with absorbing material is analyzed. The results show the RCS can be greatly reduced when we coat the absorbing material at some special parts of the object.

Transport Modeling of Optical Transport Network Nodes

TAO Zhenning,WU Deming,XU Anshi

2001, 37(1):  74-80. 

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The concept of OTN Node Transmission Model is introduced. The requirement of OTN Node Transmission Model is discussed. This model uses the frequency domain transmission matrix to express the OTN node transport characteristics. The simplified model based on WDM and IM-DD systems, the relationship between node characteristics and model parameters and measurement of model parameters are also discussed. At last a briefly discussion on how to develop the OTN simulation and CAD software based on our model is demonstrated.