共查询到19条相似文献,搜索用时 109 毫秒
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采用旋度算子的方法研究流体动力学方程组固壁边界问题的奇异极限。克服大参数和边界所引出的困难,直接对解作能量估计,证明了局部可微解的存在和唯一性定理。推广了文献中关于Cauchy问题的结果。 相似文献
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考虑具张弛正压气体动力学方程组Cauchy问题,利用极值原理证明了张弛在保证"小始值"解的光滑性意义下具有耗散效应.这一结果不仅验证了张弛具有耗散效应,而且也丰富了拟线性双曲型方程组中耗散现象的研究. 相似文献
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引用带权的Sobolev模和牛顿迭代格式,讨论了拟线性对称双曲抛物耦合方程组的初边值问题,得到了可微解的存在和唯一性定理。 相似文献
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腹主动脉瘤壁应力应变关系的测量 总被引:1,自引:1,他引:0
目的对腹主动脉瘤壁进行单轴拉伸试验,研究其应力应变关系、极限应力和极限应变。方法腹主动脉瘤壁样品置于拉伸试验机下进行单轴拉伸直至断裂,记录拉伸过程中拉力和变形,计算应力应变关系曲线、极限应力、极限应变。分别使用指数函数和二次多项式对应力应变关系曲线进行拟合,其决定系数R2。结果指数函数方法拟合,R2的平均值为92.04%±5.42%。二次多项式拟合,R2的平均值为98.47%±1.17%。独立样本t检验显示多项式曲线拟合的R2显著大于指数函数(P<0.01)。瘤壁的极限应力为(0.809 4±0.384 2)MPa,极限应变为0.349 3±0.089 1。结论拉伸试验可用于测量腹主动脉瘤的应力应变关系、极限应力和极限应变。使用二次多项式拟合的准确性优于指数函数。 相似文献
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通过定义164号元胞自动机的基本粒子,找到了粒子的逆演化规律,从而完全确定了其极限语言,并证明了164号元胞自动机的极限语言是正规的。结果表明:用有限自动机就可以接收该极限语言。 相似文献
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用循环伏安法研究了光对电化学聚合吡咯极限电位的影响,结果表明光照可明显改变聚合吡咯的极限电位,明显加快吡咯的聚合速度,且吡咯的氧化电流和光照时间成正比。在有光条件下,氧并不直接参与吡咯的氧化过程,对聚吡咯的极限电位无显著影响。 相似文献
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将24只成年雌性SD大鼠分成正常对照组和卵巢切了作组,120天后宰杀。骨骼生物力不这测试发现,卵巢切除组腰椎极限抗压承载力和极限抗压强度均显著低于正常对照组,股骨极限抗弯承载力与正常对照组无显著性差异; 相似文献
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This paper reports the use of 3 multiple regression equations (designated as A, B, and C), established by right cardiac catheterization and rheogram of pulmonary impedance examination simultaneously, for the determination of mean pulmonary artery pressure (PAP) in 100 healthy persons and 129 cases of chronic cor pulmonale on exacerbation. By analysis and comparison of the PAP values obtained from these 3 equations, the results showed that on equation B the upper limit of the PAP in 95% normal value range was 2.439 kPa (18.34 mmHg), which correspond to the upper limit of normal value range of the PAP 2.394 kPa (18.0 mmHg) as measured by right cardiac catheterization. Also, the range 1.032-2.597 kPa (7.761-19.530 mmHg) and standard deviation 0.383 kPa (+/- 2.88 mmHg) of PAP value in healthy persons, using the equation B for measurement were less than those on equation A and C. Thus, it was illustrated that the values of PAP were more stable on equation B than those on the other equations. On the other hand, the results obtained from the PAP test with these 3 equations in 100 healthy persons and 129 cases of chronic cor pulmonale on exacerbation, indicated that the specificity on equation B for healthy persons was higher, while using equation B the sensitivity and specificity for cor pulmonale patients were higher than those equation A or C. Therefore, we suggest that equation B is more conformable to the actual circumstances and suitable for clinical application. 相似文献
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目的建立一种快速实用的方法测定依达拉奉原料药中乙酸乙酯的残留量。方法用气相色谱法,采用固定相为二乙烯苯-乙基乙烯苯型高分子多孔小球(直径为0.18~0.25mm),氮气为载气,用外标法测定依达拉奉中残留乙酸乙酯的含量。结果乙酸乙酯浓度在25~400μg/mL范围内呈良好的线性关系,响应曲线相关系数为0.9992,平均回收率为99.61%。结论本法简便,快速、实用,灵敏度高,可有效地用于依达拉奉的质量控制。 相似文献
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对高开孔率、大孔径筛板复合塔板在喷射状态下的流体力学性能进行了测定及关联,提供了必要的流体力学参数。结果表明,该塔板具有阻力低、雾沫夹带量小、操作上限速度大等特点,特别适合那些要求气相负荷大、液相负荷低的过程。 相似文献
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目的 确定湿热环境下不同作业强度时的平均体温上限,用以保证作业安全。方法 从576名受试者中筛选30名男性志愿者为受试者,年龄18~23岁,经体检和体能测试合格。每次训练前后测量体温度相关指标(包括皮肤5点温度、肛温以及由此计算出的平均体温)。与文献报道对比,确定其符合度。通过多元回归方程分析建立相关模型,并对模型进行点估计。结果 (1)受试者平均体温超过文献报道的例数占受试者的35.83%,符合度较低。(2)平均体温 ^y与环境的温度X1、湿度X2,以及劳动作业强度X3有关。其回归方程为 ^y=14.247 68+0.604 67X1-0.018 29X2+0.343 53X3,按照相关点估计的计算后形成查表。(3)使用动态耐热上限指标后,在441例次的温度指标中,平均体温超过动态上限的例数在11例次,占全部的2.49%。结论 湿热环境下人体的平均体温和环境温度、湿度、作业强度均有关,在这一基础上按照点估计计算得到的动态上限值表,具有保证作业安全的意义。 相似文献
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用化学发光法测定辣根过氧化物酶几种体系的研究 总被引:4,自引:2,他引:4
Four systems were studied used for chemiluminescent determination of HRP and the determination conditions optimized. In luminol-H2O2 (NaOH) system, HRP was determined conveniently in the range of 0.05-4 pmol, with a correlation coefficient of 0.998 for the linear log-log equation and a limit of detection of 16 fmol HRP. In pyrogallol-H2O2 (pH 6.5) system, 0.1-100 pmol of HRP were determined, based on three log-log regression equations with correlation coefficients of 0.997, 0.994 and 0.999, respectively, and limits of detection of 3-17 fmol HRP. Luminol-H2O2-para iodophenol system was used to determine HRP in the range to 10-50 fmol, based on the chemiluminescence intensity at 1 min and the correlation coefficient of the log-log equation being 0.996 with a limit of detection of 10 fmol HRP. When p-hydroxybiphenyl was used to take the place of p-iodophenol and the chemiluminescence intensity at 1 min or 3 min measured, 6-40 fmol HRP were determined with a correlation coefficient of 0.994 or 0.995 for the log-log equation and a limit of detection of 6.5 or 3.3 fmol HRP. 相似文献
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A study on the dose-effect relationship between blood lead level and FEP,ZPP,CPU,and ALAU among 250 lead smelter workers was conducted.A nonlinear regression model of a dose-effect relationship between blood lead and porphyrin metabolism indicators was dose-effect relationship between blood lead and prphyrin metabolism indicators was established.The upper limit of normal values of these indicators were estimated from blood lead levels by these nonlinear regression equations.The diagnostic significance was evaluated by multiregression and discriminant analysis.This study would be heplful to the decisionmaking policy in revising the current diagnostic criteria for occupational lead poisoning. 相似文献
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马菁 《世界中西医结合杂志》2010,5(11):951-952
目的清咽解毒颗粒由15味中药组成,其中金银花、连翘、黄芩等有一定的抑菌作用,研究对该品种微生物限度检查方法进行方法学验证,了解直接采用常规法进行微生物限度检查对结果的干扰情况,以确立该品种的微生物限度检查方法。方法按照中华人民共和国药典(2005年版)一部附录微生物限度检查法项下规定,对3个批次的清咽解毒颗粒进行了微生物限度检查方法学验证。结果清咽解毒颗粒所含的抑菌成分不影响其微生物限度检查结果。结论通过对该品种的方法学验证确定该制剂可采用常规法进行微生物限度检查,不需去除抑菌成分。 相似文献