Static grain growth in an austenitic stainless steel subjected to intense plastic straining

The post-dynamic recrystallization of an ultrafine grained 304-type austenitic stainless steel was studied during annealing at 800 and 1000°C for 7.5 to 480 minutes. The initial ultrafine grained microstructures have been developed by continuous dynamic recrystallization during isothermal multidirectional forging to a total strain of ~4 at temperatures ranging from 500 to 800°C. The post-dynamic recrystallization involves a rapid softening at early stage of annealing followed by a sluggish decrease of hardness upon further annealing. A transient recrystallization at early annealing stage results in somewhat heterogeneous microstructures in the samples subjected to previous deformation at relatively low temperatures of 500-600°C. This structural heterogeneity disappears with increasing the annealing tim

Microstructure and mechanical properties of austenitic stainless steels after dynamic and post-dynamic recrystallization treatment

The effects of dynamic and post-dynamic recrystallization (DRX and post-DRX) on the microstructure and mechanical properties of austenitic stainless steels are critically reviewed. Particularly, the paper is focused on the grain refinement and strengthening by large strain deformation including severe plastic deformation conditions. The DRX and post-DRX microstructures are considered with close relation to the operative recrystallization mechanism

Properties of bright squeezed vacuum at increasing brightness

A bright squeezed vacuum (BSV) is a nonclassical macroscopic state of light, which is generated through high-gain parametric down-conversion or four-wave mixing. Although the BSV is an important tool in quantum optics and has a lot of applications, its theoretical description is still not complete. In particular, the existing description in terms of Schmidt modes with gain-independent shapes fails to explain the spectral broadening observed in the experiment as the mean number of photons increases. Meanwhile, the semiclassical description accounting for the broadening does not allow us to decouple the intermodal photon-number correlations. In this work, we present a new generalized theoretical approach to describe the spatial properties of a multimode BSV. In the multimode case, one has to take into account the complicated interplay between all involved modes: each plane-wave mode interacts with all other modes, which complicates the problem significantly. The developed approach is based on exchanging the (k, t ) and (ω, z) representations and solving a system of integrodifferential equations. Our approach predicts correctly the dynamics of the Schmidt modes and the broadening of the angular distribution with the increase in the BSV mean photon number due to a stronger pumping. Moreover, the model correctly describes various properties of a widely used experimental configuration with two crystals and an air gap between them, namely, an SU(1,1) interferometer. In particular, it predicts the narrowing of the intensity distribution, the reduction and shift of the side lobes, and the decline in the interference visibility as the mean photon number increases due to stronger pumping. The presented experimental results confirm the validity of the new approach. The model can be easily extended to the case of the frequency spectrum, frequency Schmidt modes, and other experimental configurations

Studying self-fertility in new black currant cultivars from the VIR collection in Northwestern Russia

Background. An important task is to search for and select highly self-fertile cultivars for plant breeding programs and for setting single-cultivar plantings in commercial horticulture.Materials and methods. Cultivars were assessed for their self-fertility levels at Pushkin and Pavlovsk Laboratories of VIR in 2019–2022. Thirty black currant cultivars of eight genetic groups served as the research material. Their levels of self-fertility were tested using conventional techniques. Free pollination served as the control. The resulting data were analyzed according to the main indicators crucial for precise characterization of a cultivar’s self-fertility level: fruit setting rate, berry weight, seed yield, and fertilization effectiveness. The data were statistically processed using Microsoft Excel and the guidelines by B. A. Dospekhov. Fruit setting rate, berry weight, seed yield and fertilization effectiveness were considered for each pollination variant.Results and conclusion. Cultivars with high and stable self-fertility levels were identified as potential valuable sources for breeding programs: ‘Partizanka Bryanskaya’ (k-45548), ‘Ben Gairn’(k-45524), ‘Litvinovskaya’ (k-45542), ‘Mushketer’ (k-45544), ‘Raduzhnaya’ (k-45549), ‘Ben Lomond’ (k-32611), and ‘Vertikal’ (k-45528). Cvs. ‘Partizanka Bryanskaya’ (k-45548), ‘Ben Gairn’ (k-45524), ‘Mushketer’ (k-45544), and ‘Vertikal’ (k-45528) may be used in single-cultivar plantings because they are able to set the same number of berries under natural self-pollination and free pollination. Natural self-pollination (autogamy) led to a decrease in the size of berries and the number of seeds in them. An increase in the main self-fertility indicators was observed under artificial self-pollination and free pollination

EVALUATION OF SELF-FERTILITY IN BLACK CURRANT CULTIVARS IN THE NORTHWEST OF RUSSIA

Background. High yield is one of the main requirements for modern black currant cultivars. It depends on many factors, but is always linked to self-fertility. Highly selffertile cultivars are of particular importance in areas with unfavorable weather conditions during flowering, because they are able to provide high yields even in single-cultivar plantings. In this regard, it is very important to study selffertility of cultivars in order to identify those with the highest level of this character for use in breeding and large-scale cultivation.Materials and methods. The study of selffertility was carried out at Pushkin and Pavlovsk Laboratories of VIR in 2014–2017. Fifty-seven black currant cultivars of different genetic and ecogeographic origin were the material of the research. The degree of self-fertility was measured by conventional techniques in 3 variants of pollination: 1) natural self-pollination; 2) artificial self-pollination; and 3) free pollination. Statistical data processing was performed using Microsoft Excel and the guidelines by B. A. Dospekhov.Results and conclusions. Highly self-fertile cultivars were identified, which may be recommended for breeders as sources of this trait: ‘Navlya’ (k-42228), ‘Dobrynya’ (k-42121), ‘Golubichka’ (k-32624), ‘Golosievsky velikan’ (k-44176), ‘Valentina’ (k-15631A), ‘Kozatskaya’ (k-44187), ‘Arapka’ (к-44175), ‘Kanakhama’ (k-44197) and ‘Fat’ (k-42509). High yield in the Northwest of Russia can be secured by cultivars that combine high self-fertility with large fruit size: ‘Valentina’ (k-15631A), ‘Vernisazh’ (k-43126), ‘Garmoniya’ (k-40677), ‘Dobrynya’ (k-42121), ‘Desertnaya Ogoltsovoy’(k-45670), ‘Joninai’ (k-43124), ‘Kanakhama’ (k-44197), ‘Karri (k-44172), ‘Mila’ (k-40673), ‘Sevchanka’(k-45551), ‘Sofievskaya’(k-43131), ‘Talisman’ (k-44183), ‘Yubileinaya Kopanya’ (k-44189), ‘Shalunya’(k-41988), and accession 2780-20-33 (k-15575A). It is shown that free pollination and artificial self-pollinationprovide a positive impact on the fruit setting level, fruit weight and seed productivity. Natural autogamy, on the contrary, tends to decrease the weight of berries and the number of seeds in them