地震动的波序特征研究

基于实际地震记录的统计分析,研究地震动的波序统计特征。实验研究表明,地震动的波序特征对土体变形发展有显著影响,其应变发展时程及残余变形主要受峰值及峰值前脉冲控制。通过真实地震动的统计分析研究其波序特征,结果表明：峰值前后脉冲个数的对数与截断比呈线性递减关系,与震级呈线性递增关系。当截断比小于0.5时,峰值后脉冲个数大于峰值前脉冲个数,二者之比的范围为3.1-1.2,当截断比大于0.5时,峰值后与峰值前脉冲个数差别变小,二者之比为1.2-1.0。

石油闪点测定仪分段式线性控温系统

分段式线性控温系统是石油闪点测定仪的核心部分,是确保石油闪点测试条件的关键环节。本文提出了一种全周波为最小调节量且分布均匀的控制电炉加热线性升温的波序控制方法。现场使用和实验表明,分段式线性控温系统的控制性能满足石油闪点测定的GB/T3536 83国家标准,并具有较高的控制精度和线性度。

Signal and Data Processing of Television Based on Multistatic Radar Systems

A television based multistatic radar system is described. The commercial television transmitter is used as the illuminator in the multistatic radar system. The reflected commercial television signals are measured by an array of sensors. A data processing scheme is developed that adapts to the poor signal processing ability. The innovation is focused on the construction of the observation space, which could reduce the non linearity error. The new method leads to better system stability than the traditional one. Monte Carlo simulation is utilized and compared with the traditional method.

空穴掺杂超导体的超导电性

在二维空穴掺杂t-t′-J-U模型和重整化平均场理论的框架下,用Gutzwiller方法研究了电子次近邻跃迁对空穴掺杂超导体的超导电性的影响。在掺杂浓度小于0.1的欠掺杂区,随着电子次近邻跃迁的增大,超导序参数在欠掺杂区域受到抑制,而在过掺杂区得到加强。

Modeling Nonstationary Time Series for Gyroscopic Drift Analysing

A state space aproach for modeling nonstationary time series is employed in analysing gyro transient process. Based on the concept of smoothness priors constraint, the overall model is using the Kalman filter and Akaike's AIC criterion.Some numerical results of gyro drift models are obtained for analysis of gyro system. As the trend and irregular components of the observed time series can be modeled simultaneously, it is statistically more accurate and efficient than that modeled separately.

gossamer超导体基态相图的研究

在t-t-′J-U模型下,应用Gutzwiller平均场近似的方法,研究了gossamer超导体基态情况下的相图。结果表明,大U极限下,在欠掺杂区域,反铁磁序和d波超导序在很大的掺杂浓度范围内都共存。随着次近邻跃迁的增大,超导序参数在欠掺杂区域受到抑制,在最佳掺杂和过掺杂区域得到加强,从而导致反铁磁序和d波超导序共存区域变大,d波超导序在较大的掺杂浓度范围内一直存在。这些都与数值计算结果的趋势一致。

视频广告监播中的图像匹配方法研究

在视频广告监播系统中,首先对视频广告进行关键帧的提取,然后对所提取的图片进行预处理,然后进行图像匹配。传统的方法是对图像二值化,利用序贯相似性检测算法进行图像匹配。本文提出将图像灰度化后,利用小波对图像进行边缘检测,采用基于图像边缘特征的启发式快速匹配算法,这样能提高匹配速度,提高识别效率,在视频广告监播系统中达到实时监播的作用。

LINEAR FILTERING FOR VASICEK TERM STRUCTURE MODEL WITH SEQUENTIALLY CORRELATED NOISE

When Kalman filter is used in the estimation of Vasicek term structure of interest rates,it is usual to assume that the measurement noise is uncorrelated.Study results are more favorable to the assumption of correlated measurement noise.An augmented state Kalman filter form for Vasicek model is proposed to optimally estimate the unobservable state variable with the assumption of correlated measurement noise.Empirical results indicate that the model with sequentially correlated measurement noise can more accurately describe the dynamics of the term structure of interest rates.

论配电线路线损

根据国家电网统计线损数据,目前配电线路线损率约为10%-15%,高压输电线路线损率均小于3%。提出产生线损过大的原因,以理论模型建立线损解决方法,为改造配电网制定降损思路提出理论科学依据。应用相-特变换矩阵理论[1]分析,对于不平衡、不匹配供电方式所产生线损由来,即正序波的相量(不平衡时三矢量幅值不等相角差为120°)转换为特征矢量时,产生过多的"0"序波[2],是造成线损过大的根源。

Wavelet matrix transform for time-series similarity measurement

A time-series similarity measurement method based on wavelet and matrix transform was proposed,and its anti-noise ability,sensitivity and accuracy were discussed. The time-series sequences were compressed into wavelet subspace,and sample feature vector and orthogonal basics of sample time-series sequences were obtained by K-L transform. Then the inner product transform was carried out to project analyzed time-series sequence into orthogonal basics to gain analyzed feature vectors. The similarity was calculated between sample feature vector and analyzed feature vector by the Euclid distance. Taking fault wave of power electronic devices for example,the experimental results show that the proposed method has low dimension of feature vector,the anti-noise ability of proposed method is 30 times as large as that of plain wavelet method,the sensitivity of proposed method is 1/3 as large as that of plain wavelet method,and the accuracy of proposed method is higher than that of the wavelet singular value decomposition method. The proposed method can be applied in similarity matching and indexing for lager time series databases.

Eliminating shrinkage defects and improving mechanical performance of large thin-walled ZL205A alloy castings by coupling travelling magnetic fields with sequential solidification

ZL205 A alloys with large thin-walled shape were continuously processed by coupling travelling magnetic fields(TMF)with sequential solidification,to eliminate the shrinkage defects and optimize the mechanical performance.Through experiments and simulations,the parameter optimization of TMF and the influence on feeding behavior,microstructure and properties were systematically studied.The results indicate that the magnetic force maximizes at the excitation current of 20 A and frequency of 200 Hz under the experimental conditions of this study,and increases from center to side-walls,which is more convenient to process thin-walled castings.TMF can break secondary dendritic arm and dendrites overlaps,widen feeding channels,prolong the feeding time,optimize the feeding paths,eliminate shrinkage defects and improve properties.Specifically,for as-cast state,TMF with excitation current of 20 A increases ultimate tensile strength,elongation and micro-hardness from 186 MPa,7.3%and 82.1 kg/mm^(2) to 221 MPa,11.7%and 100.5 kg/mm^(2),decreases porosity from 1.71%to 0.22%,and alters brittle fracture to ductile fracture.

A New Trial Equation Method and Its Applications

As an improved version of trial equation method, a new trial equation method is proposed. Using this method, abundant new exact traveling wave solutions to a high-order KdV-type equation are obtained.

Estimation of Shallow S-Wave Velocity Structure of Two Practical Sites from Microtremors Array Observation in Tangshan Area

Microtremors array observation for estimating S-wave velocity structure from phase velocities of Rayleigh and Love wave on two practical sites in Tangshan area by a China-US joint group are researched.The phase velocities of Rayleigh wave are estimated from vertical component records and those of Love wave are estimated from three-component records of microtremors array using modified spatial auto-correlation method.Haskell matrix method is used in calculating Rayleigh and Love wave phase velocities,and the shallow S-wave velocity structure of two practical sites are estimated by means of a hybrid approach of Genetic Algorithm and Simplex.The results are compared with the PS logging data of the two sites,showing it is feasible to estimate the shallow S-wave velocity structure of practical site from the observation of microtremor array.

Experimental Research on the Low Frequency Wave That Radiates into the Air before the Failure of Rock

Experiments on sonic transmission show that a slabstone can directly transmit part of the energy of a wave excited by knocking or by a transducer into the air. The other part of the wave energy can generate the normal mode of vibration on the slabstone and excite measurable acoustic signals in the air. The dominant frequency is related to the size of the slabstone. These results indicate that the acoustic emission (AE) in rock also displays similar behavior if the source is shallow. It is demonstrated that with the nucleation and propagation of cracks, the dominant frequency of the radiated wave will be lower. When the frequency becomes very low, the wave can be transmitted through the rock into the air and be received by a microphone. According to the theory of similarity of size, there will be low-frequency waves before strong earthquakes because of nucleation of cracks, which can be received by special low-frequency transducers or infrasonic detectors. Before earthquakes, the mechanism of precursors could be very complicated. They might be produced by plastic creep or attributed to liquids but not brittle fracture in most cases. So the periods of the produced waves will be longer. This perhaps accounts for the lack of foreshocks before many strong earthquakes.

An Efficient Adaptive Failure Detection Mechanism for Cloud Platform Based on Volterra Series

Failure detection module is one of important components in fault-tolerant distributed systems,especially cloud platform.However,to achieve fast and accurate detection of failure becomes more and more difficult especially when network and other resources' status keep changing.This study presented an efficient adaptive failure detection mechanism based on volterra series,which can use a small amount of data for predicting.The mechanism uses a volterra filter for time series prediction and a decision tree for decision making.Major contributions are applying volterra filter in cloud failure prediction,and introducing a user factor for different QoS requirements in different modules and levels of IaaS.Detailed implementation is proposed,and an evaluation is performed in Beijing and Guangzhou experiment environment.

Windowed overlapped frequency domain block filtering approach for direct sequence signal acquisition

This study applies a windowed frequency domain overlapped block filtering approach to acquire direct sequence signals. As a novel viewpoint, the windows not only allow pulse shaping without front-end pulse-shaping filter, but also increase the performance of the spectrum sensing unit, which can efficiently be implemented into this frequency domain receiver and may further be used for spectrum sensing in cognitive radios or narrowband interference cancellation in military radios. The proposed receiver is applicable for the initial time synchroni- zation of different signals containing a preamble. These signals include single carrier, constant envelope single carder, multicarrier, and even generalized multicarrier signals, making the proposed receiver structure a universal unit. Furthermore, the receiver can be used to perform filtering with long codes and compute the sliding correlation of an unknown periodic preamble. The receiver can further be modified to handle large Doppler shifts. We will also demonstrate herein the computational complexity and analysis of the acquisition performance in Rayleigh and Rician fading channels.

Re-explanation of Weyl Quantization Scheme via Weyl Ordering Approach

We re-explain the Weyl quantization scheme by virtue of the technique of integration within Weyl orderedproduct of operators,i.e.,the Weyl correspondence rule can be reconstructed by classical functions' Fourier transfor-mation followed by an inverse Fourier transformation within Weyl ordering of operators.As an application of thisreconstruction,we derive the quantum operator coresponding to the angular spectrum amplitude of a spherical wave.

Terminal Inflorescence and Restricted Branching Genes in Lupins （L. albus L., L. angustifolius L., L. luteus L.） and Field Bean （Vicia faba L.） Breeding in Poland

The objective of this paper is to present a new ideotype of grain legume cultivar and show improvements in breeding from the introduction of the terminal inflorescence （ti） gene in field bean, and the introduction of the restricted branching （rb） gene in three lupin crops--narrow-leafed lupin, white lupin and yellow lupin. Field trials using control cultivars were conducted at the Research Center for Cultivar Testing in Poland. For each species, different trial periods were selected in which new cultivars with ti/rb genes were registered. A breeding progress was estimated by a comparison of a new cultivar to control--bridge cultivar to the next trial period. Over the past twenty years cultivar improvement using ti/rb genes has proceeded differently in these species. The newest, self-completing legume cultivars have yields comparable to traditional ones and generally are earlier and more uniform when mature. This paper shows that breeding progress in rb yellow lupin is outstanding; in rb narrow-leafed lupin and ti field bean is favorable; and in rb white lupin is moderate.

Periodic Folded Wave Patterns for(2+1)-Dimensional Higher-Order Broer-Kaup Equation

A general solution including three arbitrary functions is obtained for the (2+1)-dimensional higher-orderBroer-Kaup equation by means of WTC truncation method.Introducing proper multiple valued functions and Jacobielliptic functions in the seed solution,special types of periodic folded waves are derived.In long wave limit theseperiodic folded wave patterns may degenerate into single localized folded solitary wave excitations.The interactions ofthe periodic folded waves and their degenerated single folded solitary waves are investigated graphically and are foundto be completely elastic.

Green-Naghdi Theory,Part A:Green-Naghdi(GN) Equations for Shallow Water Waves

In this work, Green-Naghdi （GN） equations with general weight functions were derived in a simple way. A wave-absorbing beach was also considered in the general GN equations. A numerical solution for a level higher than 4 was not feasible in the past with the original GN equations. The GN equations for shallow water waves were simplified here, which make the application of high level （higher than 4） equations feasible. The linear dispersion relationships of the first seven levels were presented. The accuracy of dispersion relationships increased as the level increased. Level 7 GN equations are capable of simulating waves out to wave number times depth kd 〈 26. Numerical simulation of nonlinear water waves was performed by use of Level 5 and 7 GN equations, which will be presented in the next paper.