Бимодальность в спектрах электролюминесценции InGaAs квантовых яма-точек

The electroluminescence spectra of waveguiding structures based on quantum well-dots were investigated with polarization resolution in the temperature range of 60−300 K. It is found that the ground state emission consists of two peaks with different degrees of TE-polarization and these peaks are getting closer with temperature decrease. We attribute the bimodality to the existence of two different types of nanoobjects in the active region: the quantum well-dots, which have partially TE-polarized emission, and quantum dots emitting almost fully TE-polarized light.

Design and Optimization for Mounting Primary Mirror with Reduced Sensitivity to Temperature Change in an Aerial Optoelectronic Sensor

In order to improve the image quality of the aerial optoelectronic sensor over a wide range of temperature changes, high thermal adaptability of the primary mirror as the critical components is considered. Integrated optomechanical analysis and optimization for mounting primary mirrors are carried out. The mirror surface shape error caused by uniform temperature decrease was treated as the objective function, and the fundamental frequency of the mirror assembly and the surface shape error caused by gravity parallel or vertical to the optical axis are taken as the constraints. A detailed size optimization is conducted to optimize its dimension parameters. Sensitivities of the optical system performance with respect to the size parameters are further evaluated. The configuration of the primary mirror and the flexure are obtained. The simulated optimization results show that the size parameters differently affect the optical performance and which factors are the key. The mirror surface shape error under 30 °C uniform temperature decrease effectively decreased from 26.5 nm to 11.6 nm, despite the weight of the primary mirror assembly increases by 0.3 kg. Compared to the initial design, the value of the system’s modulation transfer function (0° field angle) is improved from 0.15 to 0.21. Namely, the optical performance of the camera under thermal load has been enhanced and thermal adaptability of the primary mirror has been obviously reinforced after optimization. Based on the optimized results, a prototype of the primary mirror assembly is manufactured and assembled. A ground thermal test was conducted to verify difference in imaging quality at room and low temperature, respectively. The image quality of the camera meets the requirements of the index despite degrading.

Evaluation of Moisture Diffusion by IR Thermography

It is well known that IRT is among the preferred instruments in the qualitative monitoring of humidity in buildings. The evaporation of water leads to a sink of thermal energy that eventually manifests as a decreasing of the temperature. The imaging and non-contact characteristics of IRT make the monitoring of this temperature decrease particularly easy and effective. Nonetheless, the quantitative extraction of some figures that make the qualitative observation more reliable is still an open problem.

F1F0 ATP Hydrolysis is a Determinant of Metabolic Rate and a Correlate of Lifespan

Dramatic rectal temperature decrease, in mice administered with a drug that specifically inhibits F1F0 ATP hydrolysis, suggests that F1F0 ATP hydrolysis is a major determinant of metabolic rate in vivo. Across twelve investigated species, less F1F0 ATP hydrolysis correlates with greater maximal lifespan.

Determination of Step Check Quality Control Thresholds on Air Temperature Data at South Tangerang Climatological Station

All data, including air temperature data, must be verified by conducting quality control using the step check method. Step check quality control is carried out by looking at the difference of a parameter in a certain period compared to the threshold value that was already determined. Therefore before carrying out step check quality control, it is necessary to determine the ceiling and floor boundaries of the difference in air temperature data every hour. The data used in this study are hourly air temperature data and hourly present weather data from weather observations at the South Tangerang Climatological Station during 2016 - 2020. In determining the threshold for air temperature step check quality control, the air temperature data is paired with weather condition data to obtain a threshold value according to rain and no rain conditions. The threshold conducted in this study is based on a check for unusual climatological values, where the limits for an unusual and impossible jump in hourly air temperature changes are determined based on a certain percentage of the data distribution. This study uses percentile analysis to determine the threshold, where 5% in the lower and upper part of the data distribution are used as the threshold. The results show various thresholds every hour. The increase in temperature dominates the changes of hourly air temperature in no-rain conditions. The highest threshold for temperature increase occurs at 00.00 – 01.00 UTC at 3.2°C and continues to decrease over time. The highest threshold for temperature decrease occurs at 09.00 UTC - 10.00 UTC at 2.2°C. In rain conditions, the increase in temperature can still occur. However, the decrease in temperature mainly occurs. The highest threshold for temperature increase during rainy conditions is 1.8°C at 01.00 - 02.00 UTC, while the highest threshold for the temperature decrease is 5.8°C at 06.00 UTC – 07.00 UTC. With these results, observers can first carry out quality control with the Step Check method before filling in the data into the system database. Thus, any suspect data either from reading errors or tool errors can be minimized and finally produce a valid dataset.

Riddance jamming of pipeline shut-off valves

The paper conciders the problems of modeling the processes of thermal deformation of valves with an ambient temperature decrease. Some type of wedge valves are exposed to jamming. Heating the valve body is used to eliminate jamming. This problem is common for rigid wedge valves but the reasons not fully explained. Sometimes the valve stem is destroyed due to the significant power of the gate valve electric drives. The aim of the study is to determine the nature of the stress distribution between the structural elements of the valve, which are the cause of jamming with an ambient temperature decrease, and to search for the parameters of the heating process that ensure minimum energy consumption and time. To study the thermal processes in the valve body, a numerical model describing the heat transfer in the structural elements and the fluid is developed. The thermal model is combined with the elastic deformation model. That allows to make compatible calculations without introducing additional errors. The thermal deformations appear in the cooling process and give rise to disproportionate changes in valve dimensions and thermal stresses. Thermal stresses are the cause of jamming. Modeling of the processes of thermal deformation with a decrease in temperature showed that pressure forces of different signs arise in the middle plane of the wedge. At the average height of the horizontal line, there is a compacting pressure and at the lower and upper points there is a stretching pressure. To eliminate the compacting forces local heating was performed in several areas of the body. It was found that the most effective option is to heat the lower hemispherical surface of the body. Heating for thirty minutes reduces the thermal stresses in the wedge and compressive forces to minimum values. For this reason, jamming of the valve is eliminated. For heating the body, a hemispherical induction heater with a magnetic core is provided. The proposed design allows the use of industrial frequency voltage without a step-down transformer and reactive power compensation.

Adaptation of anammox bacteria to low temperature via gradual acclimation and cold shocks: distinctions in protein expression, membrane composition and activities

Anammox bacteria enable an efficient removal of nitrogen from sewage in processes involving partial nitritation and anammox (PN/A) or nitrification, partial denitrification, and anammox (N-PdN/A). In mild climates, anammox bacteria must be adapted to ≤15 °C, typically by gradual temperature decrease; however, this takes months or years. To reduce the time necessary for the adaptation, an unconventional method of ‘cold shocks’ is promising, involving hours-long exposure of anammox biomass to extremely low temperatures. We compared the efficacies of gradual temperature decrease and cold shocks to increase the metabolic activity of anammox (fed batch reactor, planktonic “Ca. Kuenenia”). We assessed the cold shock mechanism on the level of protein expression (quantitative shot-gun proteomics, LC-HRMS/MS) and structure of membrane lipids (UPLC-HRMS/MS). The shocked culture was more active (0.66±0.06 vs 0.48±0.06 kg-N/kg-VSS/d) and maintained the relative content of N-respiration proteins at levels consistent levels with the initial state, whereas the content of these proteins decreased in gradually acclimated culture. Cold shocks also induced a more efficient up-regulation of cold shock proteins (e.g. CspB, TypA, ppiD). Ladderane lipids characteristic for anammox evolved to a similar end-point in both cultures which confirms their role in anammox bacteria adaptation to cold and indicates a three-pronged adaptation mechanism involving ladderane lipids (ladderane alkyl length, introduction of shorter non-ladderane alkyls, polar headgroup). Overall, we show the outstanding potential of cold shocks for low-temperature adaptation of anammox bacteria and provide yet unreported detailed mechanisms of anammox adaptation to low temperatures.HighlightsAnammox bacteria were adapted to low T by gradual acclimation and cold shocksThe shocked culture was more active (0.66±0.06 vs 0.48±0.06 kg-N/kg-VSS/d)N-respiration proteins content decreased in gradually acclimated bacteriaSeveral cold shock proteins were upregulated more efficiently by cold shocksAt ↓T, anammox adjusted ladderane membrane lipid composition in three aspectsGraphical abstract

First record of stable isotopes (δ13C, δ18O) and element ratios (Mg/Ca, Sr/Ca) of Middle to Late Jurassic belemnites from the Indian Himalayas and their potential for palaeoenvironmental reconstructions

Middle to Late Jurassic belemnites from the Spiti and Zanskar valleys in the Indian Himalayas were used for stable isotope (δ13C, δ18O) and element (Mg/Ca, Sr/Ca) analyses. Although the Himalayan orogeny deformed and altered a large portion of the collected fossils, cathodoluminescence and scanning electron microscopy in combination with analyses of iron and manganese contents allowed the identification of belemnites believed to still retain their original chemical composition. Results indicate a long-term temperature decrease from the Middle Callovian–Oxfordian to the Tithonian, which is proposed to have been caused by a concomitant drift of eastern Gondwana into higher palaeolatitudes. Reconstructed absolute temperatures depend on the used equation and assumed δ18O value of seawater, but most likely varied between 17.6 °C to 27.6 °C in the Kimmeridgian and Tithonian with average values between 22 °C to 24 °C. This way, temperatures were similar to slightly warmer than today at comparable latitudes. The reconstruction of absolute temperatures for the Middle Callovian–Oxfordian was hindered by a larger number of poorly preserved belemnites representing this time interval.

Phytohormones Regulate the Non-Redundant Response of ω-3 Fatty Acid Desaturases to Low Temperatures in Chorispora Bungeana

To explore the contribution of ω-3 fatty acid desaturases (FADs) to cold stress response in a special cryophyte, Chorispora bungeana (C. bungeana), two plastidial ω-3 FAD genes (CbFAD7 and CbFAD8) were cloned and verified in a Arabidopsis fad7fad8 mutant, before being compared with the microsomal ω-3 FAD gene (CbFAD3) on expression profile. Though these genes were expressed in all tested tissues of C. bungeana, CbFAD7 and CbFAD8 have the highest expression in leaves, while CbFAD3 was mostly expressed in non-green tissues. Low temperatures (4, 0 and -4 ℃) resulted in significant increases in trienoic fatty acids (TAs, mainly C18:3), which were consistent with the non-redundant expression of CbFAD3 and CbFAD8 in suspension-cultured cells, and the coordination of CbFAD7 and CbFAD8 in leaves. Furthermore, the contribution of CbFAD8 increased as temperature decrease in the two tissues. Our data revealed that jasmonie acid and brassinosteroids participated in the cold-responsive expression of these genes in both tissues, and the pyhtohormone regulation in leaves was more complicated with the participation of abscisic acid and gibberellin. These results point to the hormone-regulated non-redundant contribution of ω-3 CbFADs to maintain appropriate level of TAs under low temperatures, which help C. bungeana survive in cold environments.