Solid ducted rockets (SDRs) have garnered considerable attention as promising propulsion systems for hypersonic vehicles owing to their advantages, such simple structures and high specific impulse. However, the performance of this system is greatly related both working pressure free volume. Such strong uncertainties in engine pose a challenge designing gas ffow control system. In study, we incorporated an artiffcial neural network (ANN)-based variable speed integral strategy adaptive...

Prodigiosin (PG) is a secondary metabolite produced by Serratia marcescens which has promising future in food, textile, and other industries due to its bright color diverse biological activities. Currently, the production of PG mainly restricted components fermentation medium large losses during extraction process, making large-scale industrial impossible. In this study, Box–Behnken design (BBD) was used optimize response surface S. marcescens. The optimum composition found be sucrose, 16.29...

Elymus sibiricus is an important native grass in Qinghai-Tibetan Plateau. Seed shattering a serious problem for E. sibiricus, especially at harvest time. Cross breeding effective way to create new varieties with beneficial characteristic or improved traits, and broaden genetic base.In this study, we created five hybrid populations by crossing seven genotypes that have seed variation. Then, nine EST-SSR primers were used identification based on DNA fingerprinting, diversity analysis of their...

To ensure efficient railroad operation and maintenance management, the accurate reconstruction of BIM models is a crucial step. This paper proposes workflow for automated segmentation structures using point cloud data, without relying on intensity or trajectory information. The consists four main components: adaptive denoising, scene segmentation, structure combined with deep learning, model reconstruction. proposed was validated two datasets significant differences in line data. results...

Abstract The high and steep slopes along a high-speed railway in the mountainous area of Southwest China are mostly composed loose accumulations debris with large internal pores poor stability, which can easily induce adverse geological disasters under rainfall conditions. To ensure smooth construction subsequent safe operation, it is necessary to master stability evolution process accumulation slope rainfall. This article simulates using finite element analysis software’s hydromechanical...

Performing object tracking tasks and efficiently perceiving the underwater environment in real time for vehicles is a challenging task due to complex nature of environment. A hybrid excitation model based lightweight Siamese network proposed solve mismatch between objects with limited characteristics deep learning models. The neural applied residual reduce computational complexity cost while constructing deeper network. In addition, deal changeable consider timing video tracking, global (HE...

In direction-of-arrival (DOA) estimation, Cramér-Rao bound is widely used to lower the mean square error (MSE), which, however, a local bound. As global bound, existing Ziv-Zakai (ZZB) restricted by single source assumption and has not considered effect of ordering process during MSE calculation. this paper, we derive an explicit ZZB for multiple sources DOA where derivation framework first extended case. Further, order statistics are introduced describe on change priori distribution DOAs,...

Mining frequent item sets is an important issue in association rules community. This paper proposes a parallel algorithm for mining based on bit matrix. The reduces the memory space and I/O overhead, it scans database only once builds compressed It combines both top-down approach bottom-up to improve efficiency of pruning, uses dynamic scheduling multi-threaded OpenMP mine sets. experiments show that this has higher computing than Apriori algorithm.

INTRODUCTION: Photovoltaic (PV) energy sources frequently experience issues, including fragmentation, open-circuit, short-circuiting, and other common hazardous problems. The current focus of PV research is on fault detection within solar arrays. Traditional models encounter challenges in identifying errors due to uncertainties panel settings the complex nature actual structure.OBJECTIVES: This study aims introduce a novel Extreme Gradient Boosting (XGBoost) approach for diagnosis...

The aerodynamic performance of aircraft can be improved via shape morphing wings actuated by piezoelectric material. An integrated design approach piezo-actuated was developed while simultaneously considering aeroelastic tailoring the base wing and actuator optimization. main purpose to investigate how anisotropic composite substrate piezocomposite actuators affect each other in both passive active aspects. To this end, an model established using finite element method combined with unsteady...

Variable-throat adjustment is the most practical flow regulation method of solid ducted rocket ramjet (SDR). The high-fidelity mathematical model interstage valve basis for realizing high-precision gas and thrust regulation. In this paper, complex effect was divided into load throat deformation effect. mainly determined by clearance, friction torque, pneumatic torque that subjected to during operation. And primarily deposition ablation faced in gas. Therefore, we could divide three parts:...

A low profile 24 G-automotive radar antenna with dual - mode excitation is proposed. By adding ground metal discs which interacts the main to excite modes, it can introduce additional resonant points, thus enable operate over a wider frequency range. When element operates at 24.35 GHz, radiation patch excites x-mode. Areas large electric field amplitude show an +-shape. of 26.15 x- mode. x-shape. The fed by microstrip line and easy form array. 1 x 4 linear array planar are designed reduce...

Variable flow ducted rockets are excellent candidates for propulsion systems in hypersonic vehicles. However, the anti-regulation characteristics of gas not only decrease stability but also create difficulties control system design. In this study, a model predictive (MPC)–based compound algorithm that suppresses is proposed. First, mathematical involving regulation was developed to describe and analyse anti-regulation. Next, fused feedback variable included both generator pressure signal...