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991.
The purpose of this study was to investigate if there was an effect of task on determination of habitual pitch, or speaking fundamental frequency (SFF). Seven tasks commonly used to elicit habitual pitch in clinical voice evaluations were compared. Three groups of normal subjects (N = 36) were examined (adult males, adult females, and male and female prepubescent children). For the adult male (n = 12) and pediatric (n = 12) subjects, no significant effect of task was found. For the adult female (n = 12) subjects, a statistically significant (P < .001) effect of task was found. All tasks were found to have high (>0.90) test-retest reliability for all subjects. Implications of the use of one task for determination of habitual pitch are discussed, as is the possibility of a task effect on determination of other voice parameters. 相似文献
992.
Abstract Representative water samples were collected from different oases in the western desert of Egypt to examine characteristics of Egyptian groundwater. Chemical data recognized two basic groundwater types; alkali bicarbonate and alkali chloride, where sodium has the highest concentration. For each region the median SD, δ18 0 and ionic strength of water calculated from their chemical analyses are recorded and plotted. Generally, the results of isotopic content measurements of the groundwaters from the different oases in the western desert indicate the fossile origin of these waters. The values of δD and δ18 0 of the western desert oases' waters are characteristic of old paleowaters from the Nubian sand aquifer. Modern sparse rainfall data suggest that any precipitation will exhibit moderate to large positive isotopic content enrichments and cannot be a source for these waters. They have been in no connection with the Nile water, moreover the change in isotopic composition is due to evaporation which is now ineffective at deeper levels. 相似文献
993.
Sequential evaluation of continuous deformation field of semi-crystalline polymers during tensile deformation accompanied by neck propagation 总被引:1,自引:0,他引:1
The localized deformation field of high density polyethylene and polypropylene during a tensile test accompanied by neck propagation was quantitatively evaluated based on the network digital image correlation method. In the proposed method, the continuity of the deformation field around a point of interest was introduced for accurate evaluation of the displacement. The accuracy of the proposed method was verified through test images. Using the proposed method, the development of a non-uniform displacement field during tensile tests was evaluated from sequential digital images. The local strain rate was almost uniform until the nominal stress reached its maximum value. After the maximum stress was reached, non-uniform deformation developed at a part of the gauge region of the specimen. A decrease in nominal stress induced a reduction of the local strain rate at regions other than the necked zone. In this study, the cross section average local true stress, strain, and strain rate can be evaluated from the local displacement field. Thus, the relationship between these quantities was evaluated during the tensile tests. Using the proposed method, the local response under wide ranges of strain and strain rate can be evaluated from a few test conditions of tensile strain rate and a small range of tensile strain. Finally, the relationships between gradients of stress, strain, and strain rate under uniaxial tension are discussed. These non-local quantities deviated from those predicted by constitutive equations when the domain size used to evaluate the local quantities was large. 相似文献
994.
995.
景象匹配辅助导航系统匹配置信度评估方法 总被引:1,自引:0,他引:1
针对景象匹配辅助导航中,由于噪声、云层、摄像机抖动等原因导致的景象匹配可能输出错误匹配结果情况,提出一种基于证据推理的景象匹配末端置信度评估方法.首先建立序列帧时空约束关系,对匹配相关阵中峰值构建辨识框架,计算序列帧对各峰值的置信指派并利用适配因子进行折扣运算,然后采用证据推理组合规则进行融合,最后给出判决准则输出匹配... 相似文献
996.
The metal-organic framework copper-1,3,5-benzenetricarboxylate (Cu-BTC) was evaluated for its ability to selectively interact with Lewis-base analytes by examining retention on gas-chromatographic columns packed with Chromosorb W HP that contained 3.0% SE-30 along with various loadings of Cu-BTC. Scanning electron microscopy images of the support material showed the characteristic Cu-BTC crystals embedded in the SE-30 coating on the diatomaceous support. The results indicated that the Cu-BTC-containing stationary phase had limited thermal stability (220 °C) and strong general retention for analytes. Kováts index calculations showed selective retention (amounting to about 300 Kováts units) relative to n-alkanes for many small Lewis-base analytes on a column that contained 0.75% Cu-BTC compared with an SE-30 control. Short columns that contained lower loadings of Cu-BTC (0.10%) allowed elution of nitroaromatics; however, selectivity was not observed for aromatic compounds (including nitroaromatics) or nitroalkanes. Observed retention characteristics are discussed. 相似文献
997.
In this study, a chiral stability-indicating CE assay was developed for the stability evaluation of tramadol (TR) enantiomers in commercial tablets using maltodextrin as chiral selector. To investigate the stability-indicating power of the analytical method as well as stability evaluation of TR enantiomers, active pharmaceutical ingredient and TR tablets were subjected to photolysis, heat, oxidation and hydrolysis to conduct stress testing. Best separation for the TR enantiomers was achieved on an uncoated fused-silica capillary at 20 °C using borate buffer (50 mM, pH 10.2) containing 10% m/v maltodextrin. All determinations were performed by a UV detector at 214 nm. A constant voltage of 20 kV was applied to obtain the separation. The range of quantitation for both enantiomers was 5-100 μg/mL (R>0.996). Intra- and inter-day RSD (n=6) were less than 10%. The percent relevant errors were obtained to be less than 4.0 for both enantiomers. The limits of quantitation and detection for both enantiomers were 5 and 1.5 μg/mL, respectively. Degradation products resulting from the stress studies were the same for both enantiomers and did not interfere with the detection of the enantiomers. 相似文献
998.
在恒温恒压条件下,以丙酮和样本中底物作为主要耗散物的不同成分的样本对非线性化学反应机理产生不同影响,从而引起反应体系电位-时间曲线形状不同变化为特征的B-Z化学振荡体系为例,就非线性化学指纹图谱原理进行了详细研究和讨论,并提出了计算非线性化学指纹图谱系统相似度的通用方法.利用系统相似度和欧氏距离、相关系数及夹角余弦对不同生产批次古汉养生精和18种其他样本的非线性化学指纹图谱的相似度进行了计算与分析.结果表明,相关系数和夹角余弦都不能用来作为评价非线性化指纹图谱相似度的指标.利用欧氏距离公式计算指纹图谱的非参数型相似度时,能正确反映指纹图谱的特征差异,但用其计算参数型相似度时,则有时不能正确反映样本非线性化学指纹图谱特征差异的相对程度.系统相似度能最真实反映样本指纹图谱之间差异程度,是4种相似度计算方法中最好的,可用于非线性化学指纹图谱相似度计算与评价.成功提出了一种经济、简便、易行和有效的鉴别样本真伪与评价其质量的科学方法. 相似文献
999.
利用样本成分耗散物的非线性化学指纹图谱的检测方法、条件、特点和应用 总被引:2,自引:0,他引:2
分析了适用于测定样本非线性化学指纹图谱的热力学体系和动力学模型,结果表明,在远离平衡的封闭体系和无耗散物补充的敞开体系中,阻尼非线性化学反应对样本化学成分的群集表征和整体含量分析具有重要作用.以丙酮和葡萄糖等为耗散物的阻尼B—Z振荡非线性化学反应为例,研究了反应物种及其浓度、电极类型、温度、搅拌速率、样本种类及用量等影响非线性化学指纹图谱的因素,并对指纹图谱中样本化学成分的定量信息、指纹图谱的特点和应用等进行了研究.成功提出了用于鉴别和评价样本的非线性化学指纹图谱的检测条件和方法. 相似文献
1000.
Petru Blaga Teodora C?tina? Gheorghe Coman 《Applied mathematics and computation》2011,218(7):3072-3082
We construct and analyze Bernstein-type operators on triangles with curved sides, their product and Boolean sum. We study the interpolation properties and approximation accuracy. Using the modulus of continuity we also study the remainders of the corresponding approximation formulas. Finally, there are given some particular cases and numerical examples. 相似文献