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Titanium alloy and its thin-walled structures are widely used in the aerospace field. Aiming at the processing chatter and difficult-to-machine problem of titanium alloy thin-walled workpieces, rotary ultrasonic milling technology (RUM) is employed to restrict machining vibration in this paper. Firstly, for describing its dynamic characteristics, the titanium alloy web with low stiffness is equivalent to a mass-spring-damping system with three degrees of freedom. Then, a novel stability analysis method is proposed for RUM thin-walled workpiece (RUM-tww) through defining an ultrasonic function angle. Furthermore, RUM-tww stability lobe diagrams (SLDs) are achieved based on the semi-discrete method (SDM). The simulation results show that the milling stability of titanium alloy webs is improved effectively under the effect of ultrasonic vibration energy. Compared with conventional milling thin-walled workpiece (CM-tww), the stability region is increased by 80.32% within the spindle speed from 1000 to 5000r/min. Finally, the milling experiments are carried out to verify the validity and rationality of SLDs via analyzing chatter marks, cutter marks, and flatness on the machined surface. The experimental results are in good agreement with the theoretical prediction.

Resistance to pod shattering is a key domestication-related trait selected for seed production in many crops. Here, we show that the transition from shattering in wild soybeans to shattering resistance in cultivated soybeans resulted from selection of mutations within the coding sequences of two nearby genes - Sh1 and Pdh1. Sh1 encodes a C2H2-like zinc finger transcription factor that promotes shattering by repressing SHAT1-5 expression, thereby reducing the secondary wall thickness of fiber cap cells in the abscission layers of pod sutures, while Pdh1 encodes a dirigent protein that orchestrates asymmetric lignin distribution in inner sclerenchyma, creating torsion in pod walls that facilitates shattering. Integration analyses of quantitative trait locus mapping, genome-wide association studies, and allele distribution in representative soybean germplasm suggest that these two genes are primary modulators underlying this domestication trait. Our study thus provides comprehensive understanding regarding the genetic, molecular, and cellular bases of shattering resistance in soybeans. Resistance to pod shattering in crops is typically modulated by major loci each underpinned by a single gene. Here, the authors show that the transition from shattering in wild soybean to shattering resistance in cultivated soybean is underlain by selection of mutations within two neighboring genes.

The application of pure zinc (Zn) in biodegradable implants is limited by its mechanical strength. This study investigates the microstructural and textural evolution of pure Zn induced by high-strain cold rolling (up to 98% reduction) and its consequent effect on microhardness, employing x-ray diffraction (XRD), electron backscattered diffraction (EBSD), and Vickers hardness testing. The results indicate that cold rolling significantly refines the grain structure through discontinuous dynamic recrystallization (DDRX). A slight increase in grain size to 50 μm was observed at 98% reduction, which is attributed to adiabatic heating. The texture evolved from a basal orientation to a more randomly oriented state and then reverted to a basal texture. This transition is closely associated with 10–12〈10-1-1〉 tensile twinning and DDRX, wherein the formation of the DDRX texture occurred via selective growth. Microhardness exhibited a minor decrease at 96% reduction due to the weakening of the 〈11–20〉//RD texture, followed by a significant reduction at 98% reduction, attributed to the softening effect of DDRX. Additionally, adiabatic heating activated 10–10〈1–210〉 prismatic slip at elevated strains. This slip system may interact synergistically with 0001〈11–20〉 basal, 11–22〈−1–123〉 second-order pyramidal slip, and twinning to facilitate DDRX.

Soybean seed appearance quality greatly affects the marketability. The objective of this study was to identify the quantitative trait loci (QTLs) that control the appearance quality of soybean seeds. A total of 256 recombinant inbred lines from Qi Huang No.34 × Ji Dou No.17 were utilized for QTL mapping. We innovatively applied a machine vision system to quantify the seed appearance of each line. As a result of QTL mapping, a total of 145 QTLs for the machine vision parameters were detected across three environments. We integrated QTLs mapped overlapped and obtained 16 QTL hotspots in total. Of these hotspots, hotspot-4–1 was suggested to be a major locus controlling seed size, and hotspot-15 was identified to affect the seed color and texture. The mapping for principal components of the seed appearance also supported it. This study comprehensively dug up the QTLs for seed appearance quality of soybean cultivars while providing an efficient method for phenotyping of seed appearance. These results would contribute to dissecting the genetic bases of seed appearance quality for the improvement of soybean.

As soybean plays an indispensable role in the supply of vegetable oil and protein, balancing the relationship between seed quality and yield traits according to human demand has become an important breeding goal for soybean improvement. Here, 256 intraspecific recombinant inbred lines (RILs), derived from a cross between Qi Huang No.34 (QH34) and Ji Dou No.17 (JD17), were used for quantitative trait loci (QTLs) mapping with remarkable four chemical and physical properties with a purpose for exploring the distribution of excellent alleles in germplasm resources in China. A total of 25 QTLs were detected, of which 10 QTLs inherited the alleles from the parent QH34. Pedigree research on favorable alleles on these QTLs showed the process of excellent alleles pyramided into QH34. Meta-analysis of the 25 QTLs by comparing with existed QTLs in previous study identified 17 novel QTLs. QTLs with pleiotropic effects have been detected. Furthermore, three representative elite recombinant inbred lines in different locations that have great potential in soybean breeding were selected, and finally, four seed weight-related candidate genes were identified. The discovery of these QTLs provides a new guidance for combining the diversity and rarity of germplasm resources, which can effectively increase population genetic diversity and broaden genetic basis of varieties.

Phytophthora root rot, caused by oomycete pathogens in the Phytophthora genus, poses a significant threat to soybean productivity. While resistance mechanisms against Phytophthora sojae have been extensively studied in soybean, the molecular basis underlying immune responses to Phytophthora sansomeana remains unclear. In this study, we investigated transcriptomic and epigenetic responses of two resistant (Colfax and NE2701) and two susceptible (Williams 82 and Senaki) soybean lines at four time points (2, 4, 8, and 16 h post inoculation [hpi]) after P. sansomeana inoculation. Comparative transcriptomic analyses revealed a greater number of differentially expressed genes (DEGs) upon pathogen inoculation in resistant lines, particularly at 8 and 16 hpi. These DEGs were predominantly associated with defense response, ethylene, and reactive oxygen species‐mediated defense pathways. Moreover, DE transposons were predominantly upregulated after inoculation, and more of them were enriched near genes in Colfax than other soybean lines. Notably, we identified a long non‐coding RNA (lncRNA) within the mapped region of the resistance gene that exhibited exclusive upregulation in the resistant lines after inoculation, potentially regulating two flanking LURP‐one‐related genes. Furthermore, DNA methylation analysis revealed increased CHH (where H = A, T, or C) methylation levels in lncRNAs after inoculation, with delayed responses in Colfax compared to Williams 82. Overall, our results provide comprehensive insights into soybean responses to P. sansomeana, highlighting potential roles of lncRNAs and epigenetic regulation in plant defense. Core Ideas Contrasting transcriptomic responses are observed between resistant and susceptible soybean lines upon Phytophthora sansomeana inoculation. Genes associated with stress response, ethylene, and reactive oxygen species‐mediated defense pathways are upregulated after pathogen inoculation in the resistant lines. The majority of the differentially transcribed transposons are upregulated in response to P. sansomeana. A novel long non‐coding RNA is found to potentially regulate two adjacent genes responsible for defense against oomycetes. Changes in CHH methylation in long intergenic non‐coding RNAs occur later in the resistant line after pathogen inoculation. Plain Language Summary Phytophthora root rot (PRR), caused by oomycete pathogens, poses a serious threat to soybean crops. Our study aimed to understand soybean responses to a newly discovered PRR‐causing pathogen, Phytophthora sansomeana. We compared gene and transposon expression, along with epigenetic changes, in resistant and susceptible soybean lines at different time points after pathogen inoculation. Resistant and susceptible lines showed contrasting responses, with a higher number of genes changing expression at 8 and 16 h post inoculation in the resistant lines. These genes were associated with plant hormones and signaling proteins, orchestrating a complex defense response. Additionally, we observed the upregulation of transposons following inoculation, and identified a long non‐coding RNA, which appeared to regulate neighboring genes crucial for defense. Our study provides insights into how soybean copes with P. sansomeana, suggesting potential strategies for bolstering plant defenses.

Summary Seed morphology and quality of cultivated soybean (Glycine max) have changed dramatically during domestication from their wild relatives, but their relationship to selection is poorly understood. Here, we describe a semi‐dominant locus, ST1 (Seed Thickness 1), affecting seed thickness and encoding a UDP‐D‐glucuronate 4‐epimerase, which catalyses UDP‐galacturonic acid production and promotes pectin biosynthesis. Interestingly, this morphological change concurrently boosted seed oil content, which, along with up‐regulation of glycolysis biosynthesis modulated by ST1, enabled soybean to become a staple oil crop. Strikingly, ST1 and an inversion controlling seed coat colour formed part of a single selective sweep. Structural variation analysis of the region surrounding ST1 shows that the critical mutation in ST1 existed in earlier wild relatives of soybean and the region containing ST1 subsequently underwent an inversion, which was followed by successive selection for both traits through hitchhiking during selection for seed coat colour. Together, these results provide direct evidence that simultaneously variation for seed morphology and quality occurred earlier than variation for seed coat colour during soybean domestication. The identification of ST1 thus sheds light on a crucial phase of human empirical selection in soybeans and provides evidence that our ancestors improved soybean based on taste.

For the robotic milling of large components with poor rigidity, it is easy to cause machining chatter. Severe chatter reduces the machining accuracy and surface quality of the part and affects the service life of the tool. Currently, the chatter suppression of robotic machining based on ultrasonic machining technology has become a hot topic. In this paper, a chatter active suppression method is proposed by adjusting the input of ultrasonic vibration energy to improve the robotic milling stability. Firstly, according to the optimal ratio of torsional vibration energy to longitudinal vibration energy, the ultrasonic knife handle is designed to improve robotic milling stability. Then, the chatter recognition method is applied to determine whether the robot exhibits chatter. After that, a model for the relationship between ultrasonic vibration energy and chatter energy is constructed for chatter active suppression. Finally, the experiment of robotic rotary ultrasonic milling brackets is carried out. The experimental results indicate that the machining quality meets the requirements of roughness and flatness. Compared with robotic common milling, the machining efficiency could be increased by five times.

The poor rigidity of large composite material components in the helicopter has an important impact on robotic milling stability. Based on the machining stability of robotic edge trimming process, a method for calculating the component overhang is proposed in this paper. Firstly, the stability model of robotic longitudinal-torsional ultrasonic milling component (RCUM-LT) with poor rigidity is established by machining dynamics analysis. Then, the influence mechanism of variables such as ultrasonic vibration energy, workpiece overhang, and edge thickness on the stability region of robotic edge milling is explored emphatically. The calculation results show that the intake of ultrasonic energy suppresses robotic milling chatter effectively. As a result, the stability region of RCUM-LT is increased by 361.79%. In addition, the smaller the component overhang, the better the stability of edge milling will be. The effect of component thickness on RCUM-LT stability is the combined action result of modal property and dynamic milling force. Considering the influence of three variables on the stability region comprehensively, a reasonable boundary curve of the adsorption position is achieved according to RCUM-LT stability model. It provides technical support for realizing robotic edge milling composite material with high efficiency and stability. Finally, the verification experiments are carried out for stability lobes and optimal overhang length. The results show that the experimental results of RCUM-LT stability are in good agreement with the theoretical prediction. With the adsorption method proposed by this study, the surface roughness and its consistency of machined surface are significantly improved.