共查询到20条相似文献，搜索用时 46 毫秒
1.
Approximation order plays an important role in characterizing multiscaling functios.The sufficient and necessary condition of approximation order is obtained by studying M - band multiscaling functions in frequency domain. 相似文献
2.
N periodic multiresolution analysis with band M was introduced. By means of Fourier transformation and inner-product, N periodic orthogonal muhiresolution analysis with band M was studied. Expression of its scaling function space in frequency domain is obtained, the coefficients relationship of lowpass filter and highpass filter is investigated, and the elementary property of its mask is worked out. The results show that filter and mask of periodic wavelet is a series of coefficients. 相似文献
3.
This paper analyzes the principle of THS(Traditional Holo-Spectrum) technique,and in allusion to the deficiency of THS that only can be used in stationary signal,a new holo-spectrum technique based on order tracking is proposed.By order tracking sampling technology,non-stationary signal in the time domain is transformed into stationary signal in the angle domain,then the THS technique can be applied.Through this way,the influence of non-stationary to THS is reduced and the application of THS is extended.The paper researches the principle of order tracking holo-spectrum and verified by a simulation experiment.The simulation result and error analysis demonstrate that this method can be valid used to analyze the non-stationary signal.The spectrum is distinct and the effect is apparent. 相似文献
4.
The authors discuss the finite groups with 52 p elements of maximal order,and get a theorem as follows: SupposeG is a finite group with |M(G)|=52 p elements of maximal order,where p is a prime and p>5,then G is solvable. 相似文献
5.
Zhang Xiangwei Xu Meihe 《保鲜与加工》1991,(2):47-55
A simplified procedure is presented for the determintion of rates of change of frequency response function matrix of system for the non-proportional changeable damping ,by means of the second order perturbation technique in conjunction with complex modal analysis. Consequently, when excitation information in frequency domain is known,the sensitivity of the response power spectra and the response time history can be obtained. 相似文献
6.
Wang Tingkai Wang Lichun 《保鲜与加工》1990,(4):57-65
This paper combines model reduction with system identification by means of time-domain function approximation, and presents a new time domain method of direct identification of linear reduced model and model reduction, and demonstrates existence theorem of its solution and criterion of order determination. Simulation tests show that the method is simple, accurate with few data requirement. 相似文献
7.
The fault character of moving parts of rotating machinery most time is speed related. The method of order spectrum analysis is more efficient than usual frequency analysis.Two general methods for realizing order tracking are discussed, and a new order tracking method based on time-frequency analysis is proposed. The time frequency order tracking method only depends on software for order tracking, which is a strong supplement to traditional methods, and specially satisfied the require of virtual instruments, so there is a good prospect for its using. 相似文献
8.
A method to cutoff substructure low order normal modes in component mode synthesis is proposed. Frequency shifting technique is introduced in substructure free vibration differential equation. Quasi-static constraint mode is taken into coordinate transformation and the contribution of substructure low order normal modes to system middle frequency modes is reduced,thus substructure low order normal modes truncation is achieved. This technique is used to compute dynamic characteristics of a body-in-white FEM mode in the frequency band of 160~190 Hz. The results show that compared with traditional component mode synthesis,which keeps 1 836 normal modes,this method only needs 297 normal modes and saves 27.7% calculation time. It means frequency shifting technique can improve the computational efficiency for middle frequency band dynamic characteristics of complex structure. 相似文献
9.
The characteristic of broadband mobile channel is analyzed, then we construct a model of bidimensions wideband mobile channel based on delay and Doppler frequency domain. On the basis of describing OFDM theory, the design on initial physical layer of broadband cellular mobile communication systems is proposed. Simulation for base band system is ground on channel model proposed above. The results of experiment and simulation are relatively inosculated, which manifest the well prospect of the communication system proposed for future application. 相似文献
10.
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. 相似文献
11.
小麦类胡萝卜素合成途径关键基因Lcye功能分析 总被引：2，自引：0，他引：2
ZHAI Sheng-Nan GUO Jun LIU Cheng LI Hao-Sheng SONG Jian-Min LIU Ai-Feng CAO Xin-You CHENG Dun-Gong LI Fa-Ji HE Zhong-Hu XIA Xian-Chun LIU Jian-Jun 《作物学报》2020,46(10):1485-1495
小麦籽粒黄色素是面粉及面制品黄度形成的主要原因,其主要成分是类胡萝卜素。ε-番茄红素环化酶(LCYE)是小麦类胡萝卜素生物合成途径的关键酶,前人对其研究多集中于QTL定位、基因克隆和分子标记开发,而基因功能和遗传调控机制尚不明确。本研究利用TILLING技术筛选EMS诱变群体,对Lcye功能及遗传调控机制进行研究,以期深入认识小麦籽粒黄色素含量形成的分子机制。在2491份M_2代EMS诱变群体中共检测到21个Lcye基因的点突变,包含6个错义突变,2个同义突变和13个内含子突变,Lcye基因在该诱变群体中的突变频率为1/266.1kb。PARSENP软件预测分析显示,M090815(C2202T)和M091648(G3284A)两个错义突变可能严重影响蛋白质功能。MEME分析结果表明, M090815和M092230 (G2195A)突变位点位于Lcye基因保守结构域内。6个错义突变植株与野生型杂交构建的F_2代群体中, M090815突变位点显著降低籽粒黄色素含量,证实该位点对LCYE功能具有重要影响。qRT-PCR(quantitative real-time PCR)分析也显示,M090815突变位点显著降低Lcye基因表达水平,且Lcye-B1和Lcye-D1基因表达降低趋势相似,而Lcye-A1在花后14～28 d表现出补偿效应。本研究不仅验证Lcye基因功能,也为面粉及其制品颜色性状改良提供了理论依据和种质资源。 相似文献
12.
The simplified method, in which second-order elasticity analysis having undergone stiffness reduction is employed to research into sway frames' second order effect, has begun to be accepted by Chinese Standard. In the proper ascertainment of the value of stiffness reduction factor considering non-elastic characteristic, it is advisable to properly choose the checking computation method of the stiffness reduction on the basis of a comprehensive analysis of RC frame. Combined with a contrastive analysis of the present schemes in USA and New Zealand, a scheme to ascertain the RC frames component's stiffness reduction is proposed for the revision of the Chinese Standard. 相似文献
13.
棉花高质量RNA的提取及MADS-box基因保守区段的克隆 总被引：11，自引：2，他引：9
研究和探讨了一种可用于高质量棉花总RNA提取的热硼酸法,并用于棉花MADS box基因的RT PCR分析,结果表明,该方法制备的RNA质量较高,克隆得到的基因片段序列与已知MADS box基因序列之间具有较高同源性。 相似文献
14.
To provide various production for fulfilling the customer's requirements to the market has been the goal of manufacturing enterprises. The order form is the representation of customer's requirements. It has been the headstream and end-piont of the management of enterprises and SCM. The idea and it's realization of SCM to the whole process are introduced, that is driven by the order form. It's derived from several aspects, including the characteristics of the production's configuration, the type of order form and supplying, the manufacture organizing mode and the material requirements, the way of SCM in manufacturing enterprise and the model of SCM to the whole process driven by order form, realizing technique, etc. 相似文献
15.
小麦抗白粉病生化标记--过氧化物酶pⅠ 6.1酶带 总被引：3，自引：0，他引：3
采用等电聚焦凝胶电泳比较了抗、感白粉病小麦品种的过氧化物酶同工酶酶谱,发现抗、感品种之间的叶片过氧化物酶同工酶pⅠ6.1酶带(位于过氧化物酶同工酶等电聚焦凝胶电泳酶谱pⅠ6.1)在拔节期至白粉病发生期表现水平有很大差别.抗病品种中编码pⅠ6.1酶带的基因终生正常表达,该酶带在小麦全生育期均有较强的活性,染色后着色深,多属一级酶带.而该基因的表达在感病品种拔节之后受到抑制,酶带变得模糊不清甚至消失踪迹,多为三级、零级酶带.感染白粉病之后酶活性才回升,再度表现为一、二级酶带.为了探索造成这一差异的原因,比较了119株抗病品种与感品种杂交F2代和65株抗病品种/感病品种//感病品种的BC1代植株叶片过氧化物酶同工酶IEF酶谱,证明感病品种成株的pⅠ6.1酶带活性下降是因另一隐性基因所至. 相似文献
16.
玉米抗南方型锈病基因共分离分子标记的研究 总被引：1，自引：0，他引：1
本文以玉米(Zea mays L.)抗南方型锈病自交系P25和感病自交系F349的F1与F349回交,并连续回交所得BC5代的F349抗病近等基因系（nearly isogenic lines,NILs）为材料,以RGA（resistance gene analogs）的方法,在抗病自交系中克隆出一条321 bp的特异性DNA条带。根据序列比对的结果,设计出新的引物作为分子标记,在96株BC7、BC4F5NILs及其亲本和杂种F1群体上进行鉴定,其中94株的田间抗感结果与分子检测结果一致,选择的有效率达97.9%。此标记扩增效果清晰,可重复性强,在抗玉米南方型锈病的分子标记辅助育种研究中有应用价值。 相似文献
17.
In order to reduce the dangers for the investors arousing from indefinite factors in market, the balance of profit and loss is analysed. But the analysis of nonlinear balance is more close to the real state of the investment programme income and cost in the market economy. It is analysed that the various combination of income and cost curves in the square nonlinear balance, the proof for a common conclusion is obtained. This conclusion can make it convenient to gain balance point in the analysis of the square nonlinear balance. 相似文献
18.
通过短期和长期试验相结合,研究减施磷肥对水稻产量和磷肥利用的影响。短期试验设置常规基施磷肥（P1）、磷肥减半基施（P2）和磷肥减半且基肥和穗肥各50%施用（P3）3个处理,以常规稻粤晶丝苗2号和杂交稻晶两优华占为供试材料,进行早晚两季试验;长期定位试验包含不施磷（M0）和常规施磷（M1）2个处理,采用9年18季试验数据。短期试验结果表明,磷肥减施对水稻产量、干物质积累量与转运、磷素积累量与利用等性状指标均无显著影响。P1、P2和P3处理间土壤总磷和可溶性磷含量均无显著差异,并且田面水总磷和可溶性磷含量在全生育期内无显著差异。P1、P2和P3处理的磷素盈亏率分别为8.7%、-35.3%和-31.8%,P1处理可达到土壤磷素表观平衡。长期定位试验结果表明,M0处理的产量随种植季节数增加而下降,3年6季内M0与M1处理产量相当。根据目前稻田土壤磷含量情况,在生产上3年内磷肥减半施用,既不影响水稻产量,又可降低稻田磷素损失风险,是兼顾产量和环保的技术方案。 相似文献
19.
黄淮麦区小麦品种演变的辈序分析 总被引：1，自引：0，他引：1
通过３０年来黄淮区麦区推广各植的１５个主要小麦品种的辈序分析，阐述了各辈次的遗传特征及相互关联，揭示了辈序质变的内在因素，探讨了小麦品种演变的基本规律，并就如何利用这些经验和现有品种基础，提出了建议。 相似文献
20.
This paper points out that the price, quality, the level of supplying on time, the level of after-sales service and so on can be regarded as resources that the suppliers can provide, and proposes a concept called the comprehensive level of resources exploitation which can be used to evaluate the comprehensive effect of order quantities allocation of one product between several suppliers. A relative index is presented to measure the comprehensive level of resources exploitation. The index is fit for comparison between several order quantities allocation plans in different time to evaluate which plan exploits the resources of suppliers more effectively. Finally, this paper establishes a linear programming model to solve the optimal order quantities allocation based on the highest comprehensive level of resources exploitation. 相似文献