The effect of temperature on high-resolution TEM image contrast

Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

2021 ◽  
pp. 107754632110026
Author(s):  
Zhou Sun ◽  
Siyu Chen ◽  
Xuan Tao ◽  
Zehua Hu

Under high-speed and heavy-load conditions, the influence of temperature on the gear system is extremely important. Basically, the current work on the effect of temperature mostly considers the flash temperature or the overall temperature field to cause expansion at the meshing point and then affects nonlinear factors such as time-varying meshing stiffness, which lead to the deterioration of the dynamic transmission. This work considers the effect of temperature on the material’s elastic modulus and Poisson’s ratio and relates the temperature to the time-varying meshing stiffness. The effects of temperature on the elastic modulus and Poisson’s ratio are expressed as functions and brought into the improved energy method stiffness calculation formula. Then, the dynamic characteristics of the gear system are analyzed. With the bifurcation diagram, phase, Poincaré, and fast Fourier transform plots of the gear system, the influence of temperature on the nonlinear dynamics of the gear system is discussed. The numerical analysis results show that as the temperature increases, the dynamic response of the system in the middle-speed region gradually changes from periodic motion to chaos.


Author(s):  
Yiqun Huang ◽  
Pawan Singh Takhar ◽  
Juming Tang ◽  
Barry G Swanson

Rheological behaviors of high acyl (HA) gellan are not well understood partially because of its relatively late commercialization compared to low acyl gellan. The objective of this study was to investigate the effect of temperature (5-30 °C), calcium (0, 1 and 10 mM) and gellan concentrations (0.0044-0.1000% w/v) on the flow behaviors of high acyl gellan aqueous solutions using rheological tests. Gellan solutions with 0 or 1 mM added Ca++ exhibited shear thinning behavior at gellan concentrations above 0.0125%. The influence of temperature on apparent viscosity (shear rate, 100 s-1) of gellan solutions can be described with an Arrhenius relationship. The apparent viscosity of gellan solution at low concentrations was more sensitive to temperature changes. The addition of Ca++ led to a decrease in flow resistance for a dilute gellan solution (<0.0125%), but an increased resistance for a relatively concentrated gellan solution (>0.0125%).


The X-ray inelastic scattering phenomena during the time-dependent perturbations are described with the aid of dynamical dispersion equations coupled with charge current in the Maxwell equations towards the appearance of the Debye-Waller factor driving the absorption coefficient, either for inelastic thermal diffusion and the Compton scattering, respectively.


2021 ◽  
Vol 99 (1) ◽  
pp. 18-23
Author(s):  
Charlie Joe Croxford ◽  
Rajpreet Kaur ◽  
Kultar Singh ◽  
Mandeep Singh Bakshi

Stable colloidal zein nanoparticles (NPs) were synthesized by using controlled precipitation method. They were made fluorescence active by incorporating a small amount of fluorescence quinolinium surfactant. The incorporation of fluorescence surfactant provided both the colloidal stability and the fluorescence ability to determine the phase transition in zein NPs under the effect of temperature variation. Maintaining colloidal stability under the effect of temperature variation is an essential aspect of zein NPs applicability as a source of vegetarian protein supplement in different food suspensions. Different techniques such as fluorescence, DLS size, zeta potential, and FTIR measurements were applied to determine the influence of temperature on the colloidal stability of zein NPs. Zein NPs undergo phase transition well above room temperature while maintaining their size in nanometer range, and the phase transition temperature decreased with the amount of zein used in the synthesis of zein NPs. The results highlighted the potential use of zein NPs as a vegetarian supplement protein in different food products.


1970 ◽  
Vol 15 ◽  
pp. 41-46 ◽  
Author(s):  
MM Rahman ◽  
W Islam ◽  
KN Ahmed

Xylocoris flavipes (Reuter) is one of the dominant predators of many stored product insect pest including Cryptolestes pusillus. The influence of temperature on predator development, survival and some selected life history parameters was determined. Eggs laid/female (27.27±2.52) and egg hatching rate (%) (88.25±2.19) were highest at 30°C and lowest at 20°C (5.43±1.19 and 30.79±4.63%) respectively but no eggs laid at 15°C. Mortality among immature stages (%) was highest (51.71±1.48) at 35°C and lowest (24.25c±1.14) at 25°C. Developmental times decreasing with the increasing of temperature. Maximum numbers of progeny/female/day (3.55±0.76) were produced at 25°C and minimum (0.83±0.04) were at 20°C.The sex ratios (% female) of X. flavipes were 47.04, 56.68, 51.66 and 50.07 for 20, 25, 30 and 35°C respectively. Survivorship of ovipositing females was highest at 25°C but lowest at 35°C respectively. Key words: Xylocoris flavipes, Cryptolestes pusillus, life history, temperature, developmental time   doi: 10.3329/jbs.v15i0.2201 J. bio-sci. 15: 41-46, 2007


2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.


e-Polymers ◽  
2014 ◽  
Vol 14 (5) ◽  
pp. 323-333 ◽  
Author(s):  
Soghra Ramazani ◽  
Mohammad Karimi

AbstractThe present work shows the effect of temperature on successfully obtained uniform electrospun poly-(ε-caprolactone) (PCL) fibers, with specific attention to the molecular orientation and diameter of nanofibers. Experiments were performed at temperatures (T) of 25°, 35°, and 45°C, and at PCL concentrations (w) of 12, 16, and 20 wt.%. Scanning electron microscopy provided the morphology of electrospun fibers and quantified their diameters. Elevated temperature for all PCL concentrations yielded a viscosity that allows for easier stretching of the jet to obtain a smaller diameter for fibers. A minimum size of the fiber diameter (close to 100 nm) was achieved for the set point T=45°C and w=12 and 16 wt.%. Due to the easy stretching of the jet by controlling the elastic property of the solution, a dichroic ratio of 1.62 was accessible for the set point T=35°C and w=12 wt.% from polarized Fourier transform infrared spectra as a factor for the orientation of PCL chains.


2021 ◽  
Vol 37 (6) ◽  
pp. 1359-1365
Author(s):  
Adjo Cynthia Kouakou ◽  
Agbékonyi Kokou Agbodan ◽  
Kwami Lumo Awaga ◽  
Awèdéou Bakpo ◽  
Eyawèdeou Yelegue ◽  
...  

Tchoukoutou is a local alcoholic drink made from sorghum. The optimization and good quality of this drink depend on certain factors such as temperature that were the subject of our work. To carry out this study, we have set ourselves the general objective of structuring the production of Tchoukoutou. Specifically, the study aims to systematize the cooking of the wort, to verify the properties of the beer through tests and to produce a quality drink. An investigation was made on the influence of temperature on sorghum germination and wort cooking. The study of the effect of temperature on the germination of sorghum was carried out. It concerned four different temperature levels which are: 23 ° C, 26 ° C, 30 ° C and 35 ° C. A study of the influence of temperature on brewing was done with different varieties of sorghum and also at different temperature ranges: 78 ° C, 83 ° C, 89 ° C, and 92 ° C. The results showed that the ideal germination temperature is 30 ° C and for brewing it is 78 ° C. The soaking time during germination, for a good germination rate, is between 16h and 26h. In conclusion, the temperature factor is a parameter that should not be overlooked when making Tchoukoutou. Our study thus made will serve as a basis for subsequent studies in the same direction to achieve a standardized industrial production of Tchoukoutou.


Author(s):  
M. J. Hytch ◽  
W. M. Stobbs

Even though it is now well recognised that the grain boundary stucture can be the dominant factor in limiting the critical current of the high Tc oxide YBa2Cu3O7-δ, it remains interesting to determine the degree of ordering of the [010] O-Cu-O chains in the basal planes, between the Ba atoms. This is because, although chain ordering is not apparently essential for other high Tc oxides2, it is clear that the degree of ordering and the value of Tc are closely linked for YBa2Cu3O7-δ. In this context, Ourmazd and Spence have suggested that the [100] and [010] orientations can at least be distinguished through details of high resolution contrast. At the same time, Huxford et al amongst others, have argued that the thermal vibrations of the O atoms in the O-Cu-O chains should reduce these contrast differences - making the degree of ordering hard to quantify.


Author(s):  
Т.В. ФЕДОСЕНКО ◽  
Л.К. ПАЦЮК ◽  
В.В. КОНДРАТЕНКО ◽  
Ю.Ю. УСАНОВА

При применении инновационных способов производства пищевых продуктов, например ультразвуковой кавитационной обработки, для управления параметрами ультразвукового воздействия необходима предварительная информация об исходных свойствах обрабатываемой среды – теплопроводности, плотности, вязкости, дисперсности, поверхностном натяжении, которой, особенно для пищевых продуктов, пока еще недостаточно. Цель настоящей работы – экспериментально установить влияние температуры на величину коэффициента поверхностного натяжения образцов овощных пюре из моркови, тыквы и кабачков, изготовленных на оборудовании технологического стенда по классической технологии. Из образцов предварительно удаляли дисперсную фазу центрифугированием с фактором разделения 8000 g. Супернатант фильтровали через складчатый бумажный обеззоленный фильтр и для образцов фильтрата определяли коэффициент поверхностного натяжения сталагмометрическим методом по ГОСТ 33276–2015 в сравнении с водой. Плотность пюре устанавливали пикнометрическим методом. Для определения влияния температуры на величину поверхностного натяжения образцы овощного пюре нагревали на водяной бане до 25 и 35°С. Установлено, что для всех исследованных образцов овощных пюре величина коэффициента поверхностного натяжения практически в два раза превышает значение аналогичного показателя для воды. Для математического описания зависимости коэффициента поверхностного натяжения от температуры в образцах овощных пюре использовали эмпирическую формулу Катаямы–Гуггенгейма. Установлено, что изменение коэффициента поверхностного натяжения овощных пюре под влиянием температуры практически не зависит от таксономической принадлежности исходного сырья и начальной текучести продукта. Поэтому при практическом использовании установленную зависимость необходимо исследовать отдельно для каждого вида овощного пюре. Зависимости коэффициентов поверхностного натяжения образцов кабачкового и морковного пюре от температуры практически идентичны. Наиболее выражено влияние температуры на коэффициент поверхностного натяжения тыквенного пюре, что указывает на очевидную необходимость стабилизации температуры технологического процесса для сохранения условий, не выходящих за границы оптимума его реализации. When using innovative methods of food production, for example ultrasonic cavitation treatment, to control the parameters of ultrasonic exposure, preliminary information about the initial properties of the treated medium – thermal conductivity, density, viscosity, dispersion, surface tension is necessary. The purpose of this work is to experimentally establish the effect of temperature on the value of the surface tension coefficient of samples of vegetable purees from carrots, pumpkins and zucchini made on the equipment of the technological stand. The dispersed phase was previously removed from the samples by centrifugation with a separation factor of 8000 g. The supernatant was filtered through a folded paper decontaminated filter and the surface tension coefficient was determined for the filtrate samples by the stalagmometric method according to GOST 33276–2015 in comparison with water. The density of the puree was set pycnometrically. To determine the effect of temperature on the value of surface tension, samples of vegetable puree were heated in a water bath to 25 and 35°C. It was found that for all the studied samples of vegetable purees, the value of the surface tension coefficient is almost twice the value of the same indicator for water. The Katayama–Guggenheim empirical formula was used to mathematically describe the dependence of the surface tension coefficient on the temperature in the samples of vegetable purees. It is established that the change in the surface tension coefficient of vegetable purees under the influence of temperature practically does not depend on the taxonomic affiliation of the raw material and the initial fluidity of the product. Therefore, in practical use, the established dependence should be investigated separately for each type of vegetable puree. The temperature dependences of the surface tension coefficients of zucchini and carrot puree are almost identical. The influence of temperature on the surface tension coefficient is most pronounced in pumpkin puree, which indicates the obvious need to stabilize the temperature of the technological process in order to maintain conditions that do not exceed the optimal limits of its implementation.


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