氢化物发生-原子荧光光谱法测定食品添加剂磷酸中铅的测量不确定度评定

按照测量不确定度评定的通用规则,建立了数学模型,对氢化物发生-原子荧光光谱法测定食品添加剂磷酸中铅的测量不确定度进行了评定,分析了方法中的不确定度分量及其来源,计算了各分量的不确定度,最后计算出了检测结果的合成标准不确定度和扩展不确定度。检测结果和不确定度评定结果为(0.190±0.006)mg/kg,k=2。结果表明标准溶液配制是氢化物发生-原子荧光光谱法测定食品添加剂磷酸中铅含量不确定度的主要影响因素。     

高效液相色谱法测定黄柏中盐酸小檗碱含量的不确定度评估

介绍一种高效液相色谱法测定含量的不确定度计算方法.通过黄柏中盐酸小檗碱含量测定结果,对产生不确定度的各分量进行计算,研究测量不确定度的主要分量,以控制检验环节的质量,保证结果准确度.     

火焰原子吸收光谱法测定工作场所空气中铜及化合物的不确定度评定

通过对火焰原子吸收光谱法测定工作场所中铜及化合物含量的测定过程分析,合理选择评定方法,简化并计算了测试过程中的不确定分量,计算出了相对合成不确定度和相对扩展不确定度,达到了对其测量不确定度合理评定的目的。     

ICP-AES测定人发中铁的不确定度分析

通过ICP-AES测定人发中铁的不确定度的评定实践,分析了该方法测定过程中的不确定度来源,建立了数学模型,并计算了各标准不确定度分量、合成标准不确定度、扩展不确定度等。     

容量法测定硫酸镁注射液含量的不确定度评定

讨论了容量法测定硫酸镁注射液含量中的各种不确定度影响因素。通过对测定过程中各种影响因素进行分析评估,计算出各分量的不确定度,得出合成不确定度和扩展不确定度(k=2)。建立的不确定度计算方法适用于容量法测定硫酸镁注射液含量的不确定度评价。     

ICP-AES测定钛合金中铝、钼和锆的不确定度评定

对钛合金中铝、钼和锆含量测定过程中的不确定度来源进行了辨别,并在此基础上评定了分析结果的不确定度.测量不确定度主要来源于试样称量、标准溶液配制、校准曲线拟合、各种玻璃量器的使用及测量重复性.依据不确定度评定的步骤,计算得到了各分量标准不确定度及合成标准不确定度.     

火焰原子吸收光谱法测定车间空气中钠及化合物的不确定度评定

对火焰原子吸收光谱法测定工作场所空气中钠及化合物含量的测定过程分析,合理选择评定方法,简化了测试过程中的不确定分量,计算出其相对合成不确定度和相对扩展不确定度,达到了对其测量不确定度合理评定的目的。     

大学物理实验的结果应采用不确定表示

介绍了不确定度的有关概念 ,提出了对不确定度A类分量及B类分量评定的方法 ,以及在两种分量下合成标准不确定度的表示式。结合具体的物理实验教学 ,举出了计算合成标准不确定便子。     

ICP-AES分析茶叶中Mg和K含量的不确定度评定

对用电感耦合等离子体-原子发射光谱法(ICP-AES)测定茶叶中的金属元素Mg、K含量的不确定度来源进行分析和计算.其分析方法的标准不确定度主要来源包括物质称量、线性回归拟合、溶液稀释等过程,并依据不确定度的评定方法计算各不确定度分量,结果表示茶叶中Mg、K的含量依次为1773、16666mg/kg,标准不确定度依次为...     

石墨炉原子吸收光谱法测定水样中钒的不确定度评定

采用石墨炉原子吸收光谱法(GFAAS)对水样中的钒进行测定,其测量不确定度主要来源于标准溶液配制、曲线拟合、样品的准备和重复测量.并对各个不确定度分量进行了评估和量化计算,得出标准不确定度和扩展不确定度.当水样中钒的含量为4.68μg·L-1时,其扩展不确定度为0.18μg·L-1(k=2).该不确定度表示方法在实际工作中具有较好的实用价值.     

Role of the near-electrode regions in the formation of the volume discharge heterogeneity in nitrogen in the pin-to-plane configuration

The development of streamers and sparks in nitrogen at atmospheric pressure in the pin-to-plane electrode configuration is studied in experiments and theoretical calculations. It is demonstrated that the near-electrode regions play the decisive role in streamer initiation. At a negative pin voltage, a spark is formed in the absence of fast primary streamers. At a positive pin voltage, streamer build-up is initiated by the current spots on the anode that result from the development of the ionization instabilities in the anode region. The calculations show that the formation of the current spot on the anode leads to a redistribution of the electric field in the vicinity of the anode, so that a single avalanche is transformed into a streamer under the conditions when the known criterion for streamer breakdown (the Meek-Raether criterion) is not satisfied. Original Text ? Astro, Ltd., 2006.     

论形象思维在静态宇宙模型建立中的表现

从科学史的角度论述了形象思维在静态宇宙模型建立中的作用，并结合爱因斯坦的研究风格分析了这种创造性思维形态的具体表现和特征。     

Correlation between Variations in the Number of Neutrons in the Atmosphere and in the Intensities of the Atmospheric Ozone Lines

We compare the data on the atmospheric radio emission in two ozone lines with resonance frequencies 96,228 and 101,736 MHz, obtained at the N. I. Lobachevsky State University of Nizhny Novgorod in 1996–2001, with the corresponding results of measuring the number of neutrons in the atmosphere, obtained at the Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (Troitsk, Moscow region) using the NM-64 monitor. It is shown that variations in both the optical depth and the intensity ratio of these lines correlate with variations in the number of neutrons. The maximum observed correlation coefficients for the optical-depth decrements of the lines amount to 0.5–0.6, which is about a factor of 1.5 higher than the maximum correlation coefficient for their intensity ratio. We analyze the dependence of the correlation coefficients on the time shift between data series for the ozone line intensity and the number of neutrons in the atmosphere. It is shown that correlation between these data series almost vanishes for a time shift of about 200 h. We discuss the features of the data on the number of neutrons in the atmosphere and the possibility of the solar origin of neutrons.     

Investigation of the fluctuations in the angles of arrival of laser radiation in the surface layer of the atmosphere

The fluctuations in the angles of arrival of a laser beam along a route 1200 m in length are investigated experimentally. The aperture dimensions of the transmitting and receiving devices and the beam geometry were varied during the measurements. The results obtained are compared with the results obtained by simultaneously determining the fluctuations in the angles of arrival of the radiation from a source of spherical waves. It is shown that the angles of arrival have a normal distribution. The dispersion of the angles of arrival depends on the diameter of the receiving aperture raised to the power -1/3 and increases as the angular aperture of the beam is reduced, becoming greater than the dispersion of the angles of arrival of spherical waves.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, Vol. 12, No. 1, pp. 103–106, January, 1969.     

Structure in the temperature dependence of the lifetime of the excited F-center in KCl

Evidence of a temperature-dependent structure in the lifetime of excited F-centers in KCl is reported. The sharp features are revealed when the temperature control of the sample is better than a few hundreth of a degree. For less accurate temperature control, as currently used in lifetime measurements, sharp variations of the lifetime with temperature are averaged, and the structure is not detectable. A theoretical explanation is suggested.     

放大系统在惠斯通电桥灵敏度研究中的应用

基于惠斯通电桥原理,在电位比较的基础上,加入了放大系统,通过调节放大系统的电阻,得出了在该模型下且在一定范围内,惠斯通电桥灵敏度具有一定的可调性,并发现在该模型下与待测电阻同路的电阻阻值与待测电阻阻值越接近越能获得高灵敏度,同时给出了此模型最佳适用条件。     

Solutions of the BBGKI equations in the fourth approximation in the temperature

Solutions of the Bogolyubov-Born-Green-Kirkwood-Ivon equations in the fourth approximation in the temperature are given in a class of generalized functions both for van der Waals and ionic crystals in the case of the so-called taking into account of smoothed correlations. A statistical thermodynamics of strongly anharmonic van der Waals and ionic crystals is constructed. Temperature expansions of the correlative distribution functions and thermodynamic quantities are investigated within the framework of the indicated method. The temperature dependence of cubic order is taken into account in the expression of the isochoric specific heat and the Grüneisen parameter of the listed crystals. It is shown that the temperature expansion for the isochoric specific heat of anharmonic crystals converges well for a value of the reduced temperature 0.33 T_m (T_m is the melting temperature).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 55–59, July, 1981.     

Change in the sign of the magnetoresistance effect in bilayer superconductor/ferromagnet structures under change in the type of the domain structure in the ferromagnet

The magnetoresistance effects in the bi- and trilayer hybrid planar superconductor/ferromagnet (S/F) structures based on Py (permalloy) and Nb near the superconducting transition temperature T _C are considered. It has been experimentally shown that the sign of the observed magnetoresistance peaks in the bilayer S/F systems changes from negative to positive at the permalloy layer thickness corresponding to the change in the type of domain walls from Néel to Bloch. For the Néel walls at the ferromagnet coercive fields, the negative magnetoresistance effect, which is due to a decrease in the depairing action of the exchange field E _ex, is observed in the S/F bilayers. For the Bloch domain walls, the magnetoresistance of the bilayer S/F structures is determined by the dissipative motion of Abrikosov vortices in the superconducting layer. In the trilayer F/S/F structures, the magnetoresistance is mainly due to the suppression of the superconducting order parameter in the superconducting layer under the action of the accumulation of the spin-polarized carriers near the S/F interfaces.