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排序方式: 共有497条查询结果,搜索用时 31 毫秒
51.
A. S. Lupashko G. K. Dikusar O. F. Lupu 《Surface Engineering and Applied Electrochemistry》2007,43(2):131-135
Application of a convective method and a combined method employing a high-frequency current alongside convection for drying kernels of apricot stones is experimentally studied. The drying rate, the drying rate constants, and the duration of the first and second periods are determined. The effect of a high-frequency electromagnetic field on the kinetics of the drying is analyzed. 相似文献
52.
This work investigates numerically the influence of a metallic absorption layer on the laser-based measurements of the thermal conductivity of dielectric (SiO2) and semiconductor (Si) electronic materials. The validity of the approach and the obtained results are assessed by comparison with experimental measurements obtained for gold-covered silicon dioxide samples. The results reveal the presence of behaviors associated with thermally thin and thermally thick absorption layers, depending on the ratio between the thickness of the absorption layer and the heat penetration depth. Optimal performance of the transient thermo-reflectance method was found to exist for thicknesses of metal layers falling between the identified thermally thin and thermally thick layers. 相似文献
53.
Mihailescu M Scarlat M Gheorghiu A Costescu J Kusko M Paun IA Scarlat E 《Applied optics》2011,50(20):3589-3597
This paper presents our method, which simultaneously combines automatic imaging, identification, and counting with the acquisition of morphological information for at least 1000 blood cells from several three-dimensional images of the same sample. We started with seeking parameters to differentiate between red blood cells that are similar but different with respect to their development stage, i.e., mature or immature. We highlight that these cells have different diffractive patterns with complementary central intensity distribution in a given plane along the propagation axis. We use the Fresnel approximation to simulate propagation through cells modeled as spheroid-shaped phase objects and to find the cell property that has the dominant influence on this behavior. Starting with images obtained in the reconstruction step of the digital holographic microscopy technique, we developed a code for automated simultaneous individual cell image separation, identification, and counting, even when the cells are partially overlapped on a slide, and accurate measuring of their morphological features. To find the centroids of each cell, we propose a method based on analytical functions applied at threshold intervals. Our procedure separates the mature from the immature red blood cells and from the white blood cells through a decision based on gradient and radius values. 相似文献
54.
Lenka Zají?ková Daniel FrantaDavid Ne?as Vilma BuršíkováMihai Muresan Vratislav Pe?inaChristoph Cobet 《Thin solid films》2011,519(13):4299-4308
The optical properties and structure of a-C:H films were modified by addition of nitrogen into the CH4/H2 deposition mixture. Three films prepared in capacitively coupled rf discharge were compared: (a) hydrogenated diamond like carbon film with hydrogen content of 34% and indentation hardness of 21.7 GPa, (b) hard a-C:H:N film with nitrogen content of 13% and indentation hardness of 18.5 GPa and (c) soft a-C:H:N film with nitrogen content of 10% and indentation hardness of 6.7 GPa. It is shown how the parametrized density of states model describing dielectric response of electronic interband transitions can be applied to modified a-C:H:N and how it can be combined with correct treatment of transmittance measured in infrared range using additional Gaussian peaks in joint density of phonon states. This analysis resulted in determination of film dielectric function in wide spectral range (0.045-30 eV) and provided also information about the density of states of valence and conduction bands and lattice vibrations. 相似文献
55.
György Deák Sorin Mihai Ştefania E. Deák Ilie Oancea 《Mine Water and the Environment》2007,26(4):251-255
In Romania, surface waters near underground salt mines represent a significant risk to the stability of the mine workings.
Such problems occur in many salt exploiting facilities, i.e. Slanic Prahova, Targu Ocna, Praid. In this paper, the authors
present a method of dealing with this issue at the Praid salt mine with research targeted at avoiding the hazard presented
by intrusion of surface waters into old mine workings. Monitoring activities are proposed to prevent damage due to the seepage
of Corund Creek water into the subsurface salt body, which could compromise and even produce collapses in the salt mine sanatorium
and old and new mines. 相似文献
56.
Liliana Olenic Gheorghe Mihailescu Stela Pruneanu Ioan Bratu Alexandru R. Biris Dan Lupu Grigore Sigartau Lucian B. Tudoran 《Particulate Science and Technology》2005,23(1):79-83
Gold colloidal nanoparticles (GNPs) were prepared by reducing a complex of Au+. Na3Au(SO3)2 with sodium citrate. The procedure provides control of the dimension of nanoparticles produced, which is a function of reaction time and concentration of reactants. The nanoparticles were separated by centrifugation and their characteristics and dimensions were studied using UV-Vis and IR spectroscopy and transmission electronic microscopy (TEM). 相似文献
57.
Pavel L. Komarov Mihai G. Burzo Gunhan Kaytaz Peter E. Raad 《Microelectronics Journal》2003,34(12):1115-1118
The transient thermoreflectance method has been used to measure the thermal conductivity of natural silicon and isotopically-pure silicon-28 layers that are epitaxially grown on natural silicon substrates. The measurements were performed at room temperature for both a low level (1016) and a higher level (2×1019) of Boron doping of the epitaxial layers. The results indicate a gain of approximately 55% in the thermal conductivity of Si28 as compared to that of natural Si, at both low and higher levels of doping, and a loss of approximately 19% for both types of silicon due to the higher level of doping. 相似文献
58.
William J. Brown Michael D. Basil Mihai C. Bocarnea 《The Journal of communication》2003,53(4):587-605
When Diana, Princess of Wales, was killed in 1997, a massive public outpouring of grief occurred. Six years after her death, the public and the tabloids still debate whether the paparazzi were to blame for her fatal car accident. Previous studies of celebrities suggest that psychological involvement with a celebrity will determine to what extent stories of the celebrity and their subsequent social influence will affect the general public. The same process was examined in this study of Princess Diana. To study this phenomenon, a survey administered immediately after her fatal car accident compared people's level of involvement with Princess Diana to their viewing of stories about her funeral and their attitudes toward the press. Results showed that gender and age similarities predicted involvement with Princess Diana. This involvement, in turn, predicted people's media use in response to her death and their attitudes toward the press. This finding reinforces previous studies that have shown involvement is an important variable that influences both media consumption and media effects. The authors consider implications of this research for investigating the growing international influence of celebrities through mass media. 相似文献
59.
D. Lupu A. Biris E. Indrea N. Aldea R.V. Bucur M. Morariu 《International Journal of Hydrogen Energy》1983,8(10):797-799
The hydrogenation properties of the alloys of overall formula Mg2Ni1?xFex (x ? 0.37) have been studied. In this range of composition multi-phase alloys were obtained containing Mg2Ni, Mg and more or less finely dispersed Fe in different coordination as proved by the EXAFS technique and Mössbauer spectroscopy. There is no significant substitution of Ni by Fe atoms in the Mg2Ni lattice. Two or three plateau-pressures are observed on the pressure-composition isotherms of the hydrides with the heats of formation in the range ?18.4 to 20.4 kcal/mol H2 (?77 to ?85.4 kJ/mol H2). The hydrides of the Fe containing alloys show higher desorption rates of hydrogen compared to the pure Mg2Ni hydride. 相似文献
60.
The temperature-programmed polycondensation of tetrachlorobisphenol A with chloromethylphosphonic dichloride is carried out in the sample tube of an NMR spectrometer. From the spectra during polycondensation, the instantaneous concentration of components can be determined. Phosphorus and chlorine-containing polymers with flame-retardant properties are obtained. 相似文献