Overall Parameters Design of Air-Launched Rockets Using Surrogate Based Optimization Method

In this paper, the design and optimization method of rocket parameters based on the surrogate model and the trajectory simulation system of the 3-DOF air-launched rockets were established. The Gaussian kernel width determination method based on the relationship between local density and width is used to ensure the efficiency and reliability of the optimization method, and at the same time greatly reduces the amount of calculation. An adaptive sampling point updating method was established, which includes three stages: location sampling, exploration sampling, and potential optimal sampling of the potential feasible region. The adaptive sampling is realized by the distance constraint. Based on the precision of the surrogate model, the convergence end criterion was established, which can achieve efficient and reliable probabilistic global optimization. The objective function of the optimization problem was deduced to determine the maximum load mass and reasonable constraints were set to ensure that the rocket could successfully enter orbit. For solid engine rockets with the same take-off mass as Launcherone, the launch altitude and target orbit were optimized and analyzed, and verified by 3-DOF trajectory simulation. The surrogate-based optimization algorithm solved the problem of the overall parameter design optimization of the air-launched rocket and it provides support for the design of air-launched solid rockets

A comparison of benzyl and 2-naphthylmethyl ethers as permanent hydroxyl protecting groups in the synthesis of α-galactoglycosphingolipids KRN7000 and PBS-57

<p>Due to the interest in the biological properties of marine derived α-galactoglycosphingolipids (α-GalGSLs), a lot of work has focused on the development of their synthesis. Here we conducted the direct comparison of benzyl and 2-naphthylmethyl (Nap) ethers as permanent hydroxyl protecting groups for the synthesis of KRN7000, as well as the practical synthesis of a biologically active α-GalGSLs PBS-57. This work further revealed the advantages of Nap ether over benzyl ether for permanent hydroxyl protection in the synthesis of α-GalGSLs.</p

Evolutionary dynamics of chromatin structure and duplicate gene expression in diploid and allopolyploid cotton

Polyploidy is a prominent mechanism of plant speciation and adaptation, yet the mechanistic understandings of duplicated gene regulation remain elusive. Chromatin structure dynamics are suggested to govern gene regulatory control. Here we characterized genome-wide nucleosome organization and chromatin accessibility in allotetraploid cotton, Gossypium hirsutum (AADD, 2n=4X=52), relative to its two diploid parents (AA or DD genome) and their synthetic diploid hybrid (AD), using DNS-seq. The larger A-genome exhibited wider average nucleosome spacing in diploids, and this inter-genomic difference diminished in the allopolyploid but not hybrid. Allopolyploidization also exhibited increased accessibility at promoters genome-wide and synchronized cis-regulatory motifs between subgenomes. A prominent cis-acting control was inferred for chromatin dynamics and demonstrated by transposable element removal from promoters. Linking accessibility to gene expression patterns, we found distinct regulatory effects for hybridization and later allopolyploid stages, including nuanced establishment of homoeolog expression bias and expression level dominance. Histone gene expression and nucleosome organization are coordinated through chromatin accessibility. Our study demonstrates the capability to track high resolution chromatin structure dynamics and reveals their role in the evolution of cis-regulatory landscapes and duplicate gene expression in polyploids, illuminating regulatory ties to subgenomic asymmetry and dominance.This preprint is made available from Research Square at doi: https://doi.org/10.21203/rs.3.rs-3373364/v1. Copyright 2023, The Authors. This work is licensed under a CC BY 4.0 License