Target signatures for thin surfaces

We investigate an inverse scattering problem for a thin inhomogeneous scatterer in ${\mathbb R}^m$, $m=2,3$, which we model as a $m-1$ dimensional open surface. The scatterer is referred to as a screen. The goal is to design target signatures that are computable from scattering data in order to detect changes in the material properties of the screen. This target signature is characterized by a mixed Steklov eigenvalue problem for a domain whose boundary contains the screen. We show that the corresponding eigenvalues can be determined from appropriately modified scattering data by using the generalized linear sampling method. A weaker justification is provided for the classical linear sampling method. Numerical experiments are presented to support our theoretical results.

Microclimatic features of landscapes in the territory with a sparse network of meteorological observations

Automatic monitoring of air temperature and humidity in the mountain-depression landscapes of the Tunka depression has been organized. The results of the analysis of observation data for 10 years showed significant differences in the temperature regime in different landscapes. The sites can be divided into three groups – the slopes of the depression, pine- herbaceous landscapes, and the lacustrine-bog complex of the central part. The average annual air temperature at all sites is negative and vary in range -0.7 … -2.1°C. Vegetation has the greatest influence on microclimatic characteristics. The maximum contrasts in the temperature regime of the air throughout the year are observed in open areas with cloudless skies. In winter, this is explained by radiation cooling, and in summer – by the heating of the open surface in the daytime. In this case, not only the daily amplitude of air temperature in the open areas increases, but also the largest contrasts between the open and closed areas are observed.

ELIOSYSTEMS FOR INCREASING THE EFFICIENCYOF THE USE OF SOLAR ENERGY IN CONCRETE TECHNOLOGY

Приведены результаты исследования влияния предложенных гелиосистем для повышения эффективности использования солнечной энергии в технологии бетона. При этом исследованы температурные поля бетона изделий, выдерживаемых под гелиопокрытием с межпленочным переменным сечением (МПС). Изучены влияние модуля открытой поверхности на температурный режим твердения, распределение температуры по сечению. Опыты показали эффективность использования солнечной энергии применением гелиотехнической системы для интенсификации твердения бетона в условиях сухого жаркого климата. The results of the study of the influence of the proposed heliosystems for increasing the efficiency of using solar energy in concrete technology are presented. In this case, the temperature fields of the concrete of products maintained under solar coating and under the MPS were investigated. The effect of the open surface modulus on the temperature regime of hardening, the temperature distribution over the cross section, was studied. The experiments showed the efficiency of the use of solar energy by using a solar system for the intensification of concrete hardening in a dry, hot climate.

Rapid construct superhydrophobic microcracks on the open-surface platform for droplet manipulations

Droplet-based transport driven by surface tension has been explored as an automated pumping source for several biomedical applications. This paper presented a simple and fast superhydrophobic modify and patterning approach to fabricate various open-surface platforms to manipulate droplets to achieve transport, mixing, concentration, and rebounding control. Several commercial reagents were tested in our approach, and the Glaco reagent was selected to create a superhydrophobic layer; laser cutters are utilized to scan on these superhydrophobic surface to create gradient hydrophilic micro-patterns. Implementing back-and-forth vibrations on the predetermined parallel patterns, droplets can be transported and mixed successfully. Colorimetry of horseradish peroxidase (HRP) mixing with substrates also reduced the reaction time by more than 5-times with the help of superhydrophobic patterned chips. Besides, patterned superhydrophobic chips can significantly improve the sensitivity of colorimetric glucose-sensing by more than 10 times. Moreover, all bioassays were distributed homogeneously within the region of hydrophilic micropatterns without the coffee-ring effect. In addition, to discuss further applications of the surface wettability, the way of controlling the droplet impacting and rebounding phenomenon was also demonstrated. This work reports a rapid approach to modify and patterning superhydrophobic films to perform droplet-based manipulations with a lower technical barrier, higher efficiency, and easier operation. It holds the potential to broaden the applications of open microfluidics in the future.

Ultrafast and long-range self-transport of droplets on multi-bioinspired surface with periodic gradient structure

Droplet self-transport is crucial in various fields ranging from physics to biochemistry. Despite extensive progress, existing systems for droplet self-transport still perform at low transport velocity or limited transport range. Here, a multi-bioinspired surface comprising two-dimensional gradient structures is proposed innovatively, which integrates the heterogeneous wettability with the shape gradient morphology. Droplet transport behaviors are systematically investigated from experiment, theory, and simulation. The fabricated structure achieves the ultrafast (over ~ 450 mm/s) and long-range (over ~ 200 mm) self-transport of droplets. Moreover, the fantastic scalability of this structure enables it to pump numerous multi-scale droplets from one site to the preset region with ultralow loss. Drawing inspirations, two systems have been designed to complete complex tasks on open surface. This work provides a reliable droplet manipulation strategy for various applications, such as water collection, microfluidics, and biomedicine, etc.

Rapid construct superhydrophobic microcracks on the open-surface platform for droplet manipulations

Droplet-based transport driven by surface tension has been explored as an automated pumping source for several biomedical applications. This paper presented a simple and fast superhydrophobic modify and patterning approach to fabricate various open-surface platforms to manipulate droplets to achieve transport, mixing, concentration, and rebounding control. Several commercial reagents were tested in our approach, and the Glaco reagent was selected to create a superhydrophobic layer; laser cutters are utilized to scan on these superhydrophobic surface to create gradient hydrophilic micro-patterns. Implementing back-and-forth vibrations on the predetermined parallel patterns, droplets can be transported and mixed successfully. Colorimetry of horseradish peroxidase (HRP) mixing with substrates also reduced the reaction time by more than 5-times with the help of superhydrophobic patterned chips. Besides, patterned superhydrophobic chips can significantly improve the sensitivity of colorimetric glucose-sensing by more than 10 times. Moreover, all bioassays were distributed homogeneously within the region of hydrophilic micropatterns without the coffee-ring effect. In addition, to discuss further applications of the surface wettability, the way of controlling the droplet impacting and rebounding phenomenon was also demonstrated. This work reports a rapid approach to modify and pattering superhydrophobic films to perform droplet-based manipulations with a lower technical barrier, higher efficiency, and easier operation. It holds the potential to broaden the applications of open microfluidics in the future.