共查询到20条相似文献,搜索用时 468 毫秒
1.
2.
小扰动理论预计轴流压气机旋转失速起始点的研究 总被引:1,自引:0,他引:1
本文对各种建立在小扰动理论基础上的预计旋转失速的起始条件进行了分析、统一和比较.并将它与单级轴流压气机的转子实验数据进行了关联,取得了理论值和实验值之间较好的一致性.分析了旋转失速起始条件的机理.证明了预计方法的有效性.扩大了方法的应用范围. 相似文献
3.
采用悬浮液-自吸扣背景石墨炉原子吸收法测定了高纯氧化铝中痕量元素铜、铁、钠含量.实验对灰化温度、原子化温度和自吸扣背景灯电流等石墨炉原子吸收工作条件等进行了优化,确定了最佳测定条件.样品测试采用标准水溶液进行校正,方法准确性采用氧化铝AKP-30在高温高压和浓硫酸密闭条件下溶解样品进样分析测定结果与文献报道的其他测定方... 相似文献
4.
5.
6.
7.
针对常见的两类量子交互干涉实验,Young 氏双缝干涉和超低强度长时间曝光量子交互结果显示出的明显波动统计分布特性,本文基于另一种经典概率测量模型Bayes统计依据的条件概率方法,提出条件概率变值测量模型,建立了测量模拟方法,给出了不同参量的测量公式,并对相关的重要条件进行描述.通过2个具体例子按每个函数形成四组16个直方图统计分布进行比较,对给定例子中的重要特性进行了分析.分析表明,在同步/异步、对称/反对称的作用下,条件概率测量模拟系统能针对左路、右路、双路粒子和双路波动交互作条件形成两类8种不同的统计分布.从不同的侧面显现了双路粒子同左/右路异步加算符信号之间的直接耦合关系,以及左/右路同步加算符信号与双路波动之间的干涉输出关系.在条件概率模型的条件下,单路/双路、粒子和波动的区别非常明晰,可以从中看到Feynman提炼的经典和量子统计之间的区别,统计判据直接从直方图分布中即可区分. 这类特性从基础层面显示了波/粒二重性的怪异特性,可以通过粒子性的模型完整描述. 相似文献
8.
利用白光干涉原理,借助迈克耳孙干涉仪对肥皂膜的厚度进行了非接触测量.在干涉条纹宽窄相同的条件下,对不同层数的肥皂膜进行对比测量;在干涉条纹宽窄不同的条件下,对相同层数的肥皂膜进行对比测量;通过计算给出了膜的中心厚度和不确定度,对比分析了各种条件下测量时误差产生的原因.结果表明:单层、双层膜适合在宽条纹下测量,四层膜适合在窄条纹下测量. 相似文献
9.
连续流动分析法测定烟草中水溶性糖、烟碱、氯离子的比较研究 总被引:3,自引:0,他引:3
选择了具有代表性的分析仪器进行对比实验,探讨仪器分析方法之间异同点,通过优化分析条件,完善分析方法.通过样品测试数据的比较,表明API和ALLIANCE仪器上分别测得的水溶性糖、烟碱、氯离子结果一致,为根据需要或现有条件选择实验方法提供了依据. 相似文献
10.
11.
Spectrographic voice identification: a forensic survey 总被引:1,自引:0,他引:1
B E Koenig 《The Journal of the Acoustical Society of America》1986,79(6):2088-2090
A survey of 2000 voice identification comparisons made by Federal Bureau of Investigation (FBI) examiners was used to determine the observed error rate of the spectrographic voice identification technique under actual forensic conditions. The qualifications of the examiners and the comparison procedures are set forth. The survey revealed that decisions were made in 34.8% of the comparisons with a 0.31% false identification error rate and a 0.53% false elimination error rate. These error rates are expected to represent the minimum error rates under actual forensic conditions. 相似文献
12.
13.
Sasaki S 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2008,84(2):31-57
The physiological characteristics of the dominant tree species in the tropical rain forest mainly belonging to dipterocarps as well as the environmental conditions especially for the light in the forest were studied to establish the silvicultural system for the forest regeneration in the tropical South Asia. The flowering patterns of the dipterocarp trees are usually irregular and unpredictable, which make difficult to collect sufficient seeds for raising the seedlings. The field survey revealed the diverged features of the so-called gregarious or simultaneous flowering of various species of this group. Appropriate conditions and methods for the storage of the seeds were established according to the detailed analyses of the morphological and physiological characteristics of the seeds such as the low temperature tolerance and the moisture contents. The intensity and spectra of the light in the forest primarily determine the growth and the morphological development of the seedlings under the canopy. Based on the measurements of the diffused light at the sites in the tropical forest in the varying sunlight, the parameters such as "the steady state of the diffuse light" and "the turning point" were defined, which were useful to evaluate the light conditions in the forest. To improve the survival of the transplanted seedlings, a planting method of "the bare-root seedlings", the seedlings easy to be handled by removal of all leaves, soil and pots, was developed. Its marked efficiency was proved with various dipterocarps and other tropical trees by the field trial in the practical scale. Tolerance of the various species to the extreme environmental conditions such as fires, acid soils and drought were examined by the experiments and the field survey, which revealed marked adaptability of Shorea roxburghii as a potential species for regeneration of the tropical forests. 相似文献
14.
Thode A Kim KH Greene CR Roth E 《The Journal of the Acoustical Society of America》2010,128(4):EL181-EL187
In 2008 the Louis S. St-Laurent (LSSL) surveyed deep Arctic waters using a three-airgun seismic source. Signals from the seismic survey were detected between 400 km and 1300 km range on a directional autonomous acoustic recorder deployed in water 53 m deep off the Alaskan North Slope. Observations of received signal levels between 10-450 Hz versus LSSL range roughly fit a cylindrical transmission loss model plus 0.01 dB/km attenuation in deep ice-free waters, and fit previous empirical models in ice-covered waters. The transition between ice-free and ice-covered propagation conditions shifted 200 km closer to the recorder during the survey. 相似文献
15.
A brief survey is given of theoretical works on surface states (SSs) in Dirac materials. Within the formalism of envelope wave functions and boundary conditions for these functions, a minimal model is formulated that analytically describes surface and edge states of various (topological and nontopological) types in several systems with Dirac fermions (DFs). The applicability conditions of this model are discussed. 相似文献
16.
The paper describes the results of research aimed at investigating the preferred subjective listening conditions inside churches. The effect of different musical motifs (spanning Gregorian chants to symphonic music) was investigated and regression analysis was performed in order to point out the relationship between subjective ratings and acoustical parameters. In order to present realistic listening conditions to the subjects a small subset of nine churches was selected among a larger set of acoustic data collected in several Italian churches during a widespread on-site survey. The subset represented different architectural styles and shapes, and was characterized by average listening conditions. For each church a single source–receiver combination with fixed relative positions was chosen. Measured binaural impulse responses were cross-talk cancelled and then convolved with five anechoic motifs. Paired comparisons were finally performed, asking a trained panel of subjects their preference. Factor analysis pointed out a substantially common underlying pattern characterizing subjective responses. The results show that preferred listening conditions vary as a function of the musical motif, depending on early decay time for choral music and on a combination of initial time delay and lateral energy for instrumental music. 相似文献
17.
We discuss how the dynamics of an exploding hot fireball of quark-gluon matter impacts the actual phase transition conditions
between the deconfined and confined state of matter. We survey the chemical conditions prevailing at hadronization. 相似文献
18.
The results of a noise survey made within the Portsmouth City boundaries are outlined. Measurements were made throughout the 18-hour day at 33 sites which covered a wide range of traffic conditions. Comparisons were made between the published noise prediction methods and the measured results for sites adjacent to roads carrying free-flowing traffic. A modification is introduced to allow the design parameter employed by traffic engineers to be used in the prediction formula. The fall-off of noise levels with distance was also examined. An area classification is suggested for situations where the prediction formulae are not able to be applied. 相似文献
19.
《Physica D: Nonlinear Phenomena》1988,31(1):103-116
The dynamics of a periodically driven damped Toda chain with periodic boundary conditions is investigated. With the help of energy cross sections it can be shown that besides periodic motions of different periodicity quasiperiodic and aperiodic (chaotic) motions exist. The method of energy bifurcation diagrams is introduced which allows a survey of the resonance properties of the chain. 相似文献
20.
Ulrich von Pidoll 《Journal of Electrostatics》2013,71(1):1-5
This paper gives a literature survey on recommendations for the worst case test conditions for electrostatic tests of liquid handling systems. The following applications are dealt with: 1) Testing equipment for flowing solvents, 2) Testing equipment for flowing fuel, 3) Testing equipment for flowing contaminated liquids, 4) Spraying liquids, and 5) Reconstruction of accidents. 相似文献