Parameters of Spiral V-notch Loosen Blasting

Based on the mechanism of spiral V notch loosen blasting,uncoupled explosive loading is adopted to prevent the explosion waves from breaking the wall of the blasting hole. Relative parameters of spiral V notch are analyzed and their calculating formulae are achieved. The expressions of the width of the blasted crack,the length of the developed crack and of the sizes of the blasted lumps are obtained. The relationship between the blastyed effect, the spiral angle, and the notching angle is studied, which provides a theoretical base for developing a blasting strategy with desirable lump sizes.     

STUDY OF SPECIMEN SIZES OF FRACTURE EXPERIMENTS OF CONCRETE MATERIAL

The minimum sizes of specimens that can get effective K_(10) values by 3-point bending, 4-point bending and CT methods are derived on the basis of their notch sensitivity laws and size effect equation of concrete. The results show that the minimum heights of 3-point bending and 4-point bending specimens are very similar to those from Modeer's results, and the minimum height of CT specimen increases as the relative crack length increases.     

A time-varying signal processing method for Coriolis mass flowmeter

The mass flowrate of Coriolis mass flowmeter in practical application has slow changes with time. To solve the problem, an improved time-varying signal model whose frequency, amplitude and phase are time-varying based on the random walk model is established firstly. A new algorithm of adaptive notch filter with the capability of tracking frequency variation is applied to filter the sensor output signal of Coriolis mass flowmeter and its frequency is calculated next. An adaptive line enhancer based on the mentioned notch filter extracts fundamental frequency signal from noisy data. Then, by short window intercepting, the revised sliding DTFT recursive algorithm is introduced to calculate the real-time phase difference between two enhanced signals. With the frequency and phase difference obtained, the time interval between the two signals is calculated and then the mass flowrate is derived. The simulations and field test results show that the proposed method can not only track the change of frequency and phase, but also ensure the calculation accuracy when measuring small phase difference. The computational load of the algorithm is simple so that it can be applied to real-time signal processing for Coriolis mass flowmeter.     

EEG Signal Denoising Based on Wavelet Transform

The article focuses on the method of noise cancellation for EEG signal. The method of notch filter is discussed. According to the frequency of noise and the principle of notch filter, the design result of the notch filter and the denoised signal are presented. Then, the analysis of EEG signal are proposed based on wavelet transform (WT) and noise cancellation using WT. Wavelet transform is a multi-resolution time-frequency analysis method. It can decompose mixed signal into signals at different frequency bands. The EEG signal is analyzed and denoised using WT, then the results are presented respectively. Comparing the experiment results shows that WT can detect and process noise in the EEG signal effectively.     

PD Online Measurement of Transformers with Wide Frequency Band System and the Noise Eliminating Method by Cascaded IIR Lattice Notch Digital Filter

The frequency band of conventional partial discharge (PD) measurement systems is selected just within several ten kilohertz. With the development of computer and digital signal processing techniques, wide frequency band (WFB) measurement systems have been used to detect PD in electrical equipment for its higher sensitivity. Nevertheless, the WFB measurement systems are easy suffered from the interference of strong field electromagnetism noises. A set of PD online monitoring system with frequency band from 50 kHz to 1 megahertz used for transformer is developed, in which pre-processing device and cascaded 2nd order IIR lattice notch digital filter are mainly used to suppress periodic narrow-band interference. With analysis of field monitored signal at a 220 kV substation, it is shown that the monitoring system not only can detect and extract the discharge pulse signal effectively, but also has the powerful capability of suppressing interference.     

Frequency tracking method and simulation for coriolismass flowmter based on a new adaptive notch filter

In order to improve the long-playing frequency tracking ability in the signal processing for coriolis mass flowmeter (CMF) , a new IIR adaptive notch filter (ANF) is developed via steiglitz-mcBride method (SMM) and applied to filter the sensor output signal whose frequency, amplitude and phase are time-varying following the random walk model. The proposed method can detect the signal frequency fleetly and track the frequency variations continuously. The tracking performances of the proposed method and the adaptive lattice notch filter (LANF) method are investigated with computer simulations. Simulations demonstrate the superiority of the proposed method and show it has advantages of fast convergence rate, insensitivity to initial phase variations, and higher long-playing tracking stability and accuracy than LANF method.     

Signal Processing Method for Coriolis Mass Flowmeter Based on Lattice Notch Filter and DTFT

A novel signal processing method for Coriolis mass flowmeter is proposed based on time-varying signal model. First, an adaptive lattice notch filter is applied to filter the output signal, whose frequency, amplitude and phase are time-varying based on the random walk model, of Coriolis mass flowmeter to get its frequency and enhanced signal. Then, by short window intercepting, the DTFT algorithm with negative frequency contribution is introduced to calculate the real-time phase difference between two enhanced signals. With the frequency and the phase difference, the time interval between two signals is calculated. Simulation results show that the proposed method is efficient. Furthermore, the computation of algorithms is simple so that it can be applied to real-time signal processing for Coriolis mass flowmeter.     

A METHOD FOR CALCULATING STRESS INTENSITY FACTORS OF CHEVRON-NOTCHED THREE-POINT BEND ROUND BAR SPECIMENS

An effective approximate method is proposed to obtain the stress intensity factors (SIF) of the chevron notched three-point bend round bar specimens, the least square principle is applied to fit the results into a polynomial for SIF,which is applied to the fracture toughness specimen suggested by the International Society for Rock Mechanics(ISRM) ,the result is satisfatory.     

种子活力光学无损检测技术研究进展

种子活力检测是种子检测中的重要一环,国际种子检验协会建议的检测方法主要有标准发芽实验法、TTC染色法、电导率测定和加速老化试验等方法。这些检测方法具有检测结果显示直观、测量准确等优点,但也存在对种子有破坏作用、检测过程复杂和耗时耗力等缺点。随着现代免耕直播技术的发展,对种子活力的检测在速度和无损性方面提出了更高的要求,而传统方法难以实现快速无损检测目标。基于光学技术的种子活力检测方法具有效率高、无损的特点,近年来得到了国内外相关学者的关注。本文对光学技术在种子活力检测上的应用进行了综述,介绍了X光、近红外光谱、高光谱、光声光谱、可调谐半导体激光吸收光谱和色选技术等光学技术在种子活力检测中的研究,并对光学技术在种子活力检测的前景进行了展望。     

Remote Test Method of Relay Protection

Considering the limitation of the field test for relay protection in power system, the paper studies and discusses the remote test method of relay protection in power system. It provides the technology requirements, the technology problems and restricted factors to build the protection test and analysis center. It proposes the method of building the protection test and analysis center. Considering the practice for the transmission of test data, the paper introduces the technology requirements of utilizing dispatching automation system data network to transmit the protection test data. Considering the requirements of microcomputer protection devices for remote test method, the paper presents that there are remote test function and synchronization test function in the field microcomputer protection devices.     

不同拉伸速度对卷烟纸纵向抗张强度和伸长率检测结果的影响

用统计学的方法对比了不同拉伸速度对卷烟纸纵向抗张强度和伸长率的检测结果。结果表明,在拉伸速度分别为15,17,20,22,25 mm/min时,各试验组内检测结果无显著性差异,稳定性均较好;在拉伸速度为15～25 mm/min,不同的拉伸速度对卷烟纸纵向抗张强度检测结果无显著性影响,一致性较好;不同的拉伸速度将会对卷烟纸伸长率检测结果产生显著性影响,应在检测报告中注明拉伸速度;若要保证检测结果的一致性,应选择能使检测结果无显著性差异的拉伸速度进行检测。     

Analysis on drag coefficients of bundled conductors under wind load

Drag coefficients of quad-bundled conductor under different wind speeds and attack angles are firstly determined by means of wind tunnel test. Meanwhile, the drag coefficients are obtained by numerical simulation method and the results are consistent with those by the wind tunnel test. Furthermore, cross flows around six-bundled and eight-bundled conductors are numerically investigated, and the drag coefficients are then determined. Compared with the determination method of wind load on conductor in current Chinese code and the IEC code for the design of transmission line, the drag coefficients defined in the Chinese code may be too large for bundled conductors, and may need to be adjusted based on further theoretical and wind tunnel test investigation.     

Optimization of Curve Fitting Used in Development of Magic Formula Tire Model

Characteristics of a tire are the foundation of vehicle dynamics studying, especially play a vital role in vehicle handling study. It is necessary to establish a tire model in the simulation for vehicle handling because the tire characteristics got by test can not be satisfied.The optimization of fitting to the tire test data curves by Magic Formula is discussed, included the digitalization of tire test data curves, designing objective functions and optimization processes,etc. Finally the parameters in Magic Formula tire model are obtained and they lay a foundation for the development of vehicle handling aftertime.     

固结煤矸石抗剪强度特征试验

依据现场大型剪切试验和室内直剪试验,研究了固结煤矸石的抗剪强度特性。试验剪应力-剪位移过程曲线表明,一定含水率条件下的固结煤矸石呈现明显的粘塑性体力学特性。以现场大型剪切试验煤矸石作为试样配料进行了室内直剪试验,分析了含水率和密实度对良好固结煤矸石试样剪应力-剪位移试验曲线以及抗剪强度参数的影响,在此基础上探讨了试样内煤及其它细颗粒的状态变化对固结煤矸石抗剪强度的弱化作用机理,最后对比分析了现场大型剪切试验抗剪强度参数值和室内直剪试验抗剪强度参数值的差异及其产生的主要原因。     

Application of the concepts of test value and varietal value to the study of genetic advance in recurrent selection: A synthesis

Summary The concepts of varietal ability and value in test of a genotype or group of genotypes are specified according to the type of variety (clones, hybrids, lines, synthetics) and the testing system (phenotype, S₁, General combining ability (GCA), line value, General synthesizing ability (GSA)). Varietal ability and value in test are to be considered as any quantitative characters for which it is possible to define additive effects, dominance effects and epistasis. For diploids in recurrent selection, only additive effects and additive× additive epistasis for varietal value contribute to genetic advance. Genetic advance depends on the covariance between the testing value of the parents and the test value of the progeny by intercrossing. Such a parent-offspring covariance is, in the absence of epistasis and inbreeding, one half of the covariance between additive effects in test of the parents and additive effects in test of their progenies. This allows one to express directly the genetic advance in varietal value according to the type of variety and to the testing system used in recurrent selection. The case of biallelic populations is considered; it allows some discussions on the relative values of components of variance of varietal and test values.     

Reliability model for Subsystems of CNC machine tool with small samples

Many subsystems in CNC machine tool have only a few failures, so they are small samples. In this case, classical reliability modeling method often has large errors. For the failure data of small sample, maximum likelihood estimation method is used to estimate the Weibull distribution model parameters of time between failures of the subsystems. Then, the Weibull distribution model parameters are modified by parameter bias correction method. Finally, the effect of bias correction parametersis tested by the D test and the error area ratio test method. The test results show that the modified models are better.     

新疆膜下滴灌棉田土壤水分与灌溉预报模型研究

本研究收集大量气象数据结合大田试验构建了土壤水分和灌溉预报模型,并对模型进行了检验.两个模型的检验结果均达到显著水平,其中,土壤水分模型检验结果为:RE=4.63%,RMSE=0.0113,r2=0.945,LA=0.997.灌溉预报模型检验结果为:RE=5.17%,RMSE=0.0123,LA=0.988.结果表明:...     

我国棉花品种区域试验重复次数和试点数量的设计

农作物区域试验重复次数和试点数量设置直接影响试验的遗传力和品种选择效率。本研究以2000-2014年期间长江流域、黄河流域和西北内陆棉区国家棉花区试数据为资料,依据各棉区的试验发展现状和试验遗传力随着试点数量的变化,分析重复次数和试点数量设置的合理性,提出各棉区试点数量的设置方案。结果表明: (1)我国棉花品种区域试验采用3次重复是保证试验效率的充分条件;(2)长江流域和黄河流域国家棉花区试现行的试点数量设置已经可以充分满足试验的遗传力要求,西北内陆棉区的试点数也符合遗传力达到0.75的基本要求;(3)由于棉花区域试验对品种的推荐审定和应用十分重要,试验过程中也可能会因田间管理、自然灾害或其他异常情况导致试验报废,为充分保证试验的可靠性,长江流域棉区可保持当前20个左右的试点数量,遗传力即可达到0.90的水平;黄河流域和西北内陆棉区可以分别将试点数量增加到27个和19个左右,遗传力达到0.90和0.85的水平。该结果为国家棉花区域试验的优化配置提供理论依据,也为其他作物区域试验布局提供参考。     

大白菜一代杂种及双亲幼苗的等电聚焦电泳过氧化物同工酶分析

等电聚焦电泳是近些年发展起来的分离蛋白质的有效生化技术．操作简便，分辨率高，电泳条带多而且细，信息量大，利于进行深入细致的研究。该文利用等电聚焦丙烯酰胺电泳方法分析了6个大白菜一代杂种及双亲幼苗的过氧化物同工酶电泳图谱，共分离出十几条酶带，F1杂种与亲本间同工酶图谱均表现出明现差异，特别是A鉴别区内的酶带差异最明显，大多为互补型，是主要鉴别区。进一步研究结果表明，6个大白菜品种均可利用过氧化物同工酶鉴别由自交引起的假杂种。利用这项技术大量开展了这6个品种的商品种子纯度检测工作，同时在田间进行了验证性测定，二者结果基本相符。     

Wind Tunnel Test for Section Model of Caiyuanbai Bridge Over Yangtse River

With the development of modern construction technique and the application of new material,arch bridges which progress towards small rigidity,long span and light weight,what's more is that long span bridge's rigidity under construction is much less than that in use stage.So it is very necessary to study the aerodynamic characteristics of long span bridge.The regularity of the three dimensional static component forces coefficient varying with attack angle and the girder's flutter properties of Caiyuanbai Bridge over Yangtse River are investigated with segmental molding's static wind-tunnel test and segmental molding's dynamic wind-tunnel test.Eight derivatives of the girder are also identified from the segmental molding's dynamic wind-tunnel test.Finally the assessment to wind resistant properties of the bridge is given based on detailed analysis of the test results.The conclusion which gets from analysis can provide an suggestion to design and construction this kind bridge.