Optimal deployment of swarm positions in cooperative interception of multiple UAV swarms

In order to prevent the attacker from breaking through the blockade of the interception,deploying multiple Unmanned Aerial Vehicle(UAV)swarms on the interception line is a new combat style.To solve the optimal deployment of swarm positions in the cooperative interception,an optimal deployment optimization model is presented by minimizing the penetration zones'area and the analytical expression of the optimal deployment positions is deduced.Firstly,from the view of the attackers breaking through the interception line,the situations of vertical penetration and oblique penetration are analyzed respectively,and the mathematical models of penetration zones are obtained under the condition of a single UAV swarm and multiple UAV swarms.Secondly,based on the optimization goal of minimizing the penetration area,the optimal deployment optimization model for swarm positions is proposed,and the analytical solution of the optimal deployment is solved by using the convex programming theory.Finally,the proposed optimal deployment is compared with the uniform deployment and random deployment to verify the validity of the theoretical analysis.

Dietary saccharin sodium supplementation improves the production performance of dairy goats without residue in milk in summer

The purpose of this study was to investigate the effects of dietary saccharin sodium supplementation on production performance,serum biochemical indicators,and rumen fermentation of dairy goats in summer.Twelve Guanzhong dairy goats with similar body weight,days in milk,and milk yield were randomly divided into two dietary treatments:(1)CON:basal diet;(2)SS:basal diet+150 mg/kg saccharin sodium on the basis of dry matter.The experiment lasted 35 d,including 7 d for adaptation and 28 d for dietary treatments,sampling and data collection.Each dairy goat was housed individually in a clean separate pen with ad libitum access to diet and water.The goats fed SS diet had increased dry matter intake(DMI;P=0.037),4%fat corrected milk yield(P=0.049),energy corrected milk yield(P=0.037),milk protein yield(P=0.031),and total solids yield(P=0.036).Serum activity of aspartate aminotransferase(P=0.047)and concentrations of 70-kDa heat shock protein(P=0.090),malondialdehyde(P=0.092),and total protein(P=0.057)were lower in goats fed SS diet than those fed CON diet.Supplementation of saccharin sodium tended to increase activity of glutathione peroxidase in serum(P=0.079).The concentrations of rumen total volatile fatty acid(P=0.042)and butyrate(P=0.038)were increased by saccharin sodium supplementation.Dietary supplementation of saccharin sodium increased the relative abundance of Lachnobacterium(P=0.022),Pseudoramibacter(P=0.022),Shuttleworthia(P=0.025),and Syntrophococcus(P=0.037),but reduced the relative abundance of Prevotella_1(P=0.037)and Lachnospiraceae_UCG_008(P=0.037)in rumen.Saccharin sodium was observed in feces and urine of goats fed diet supplemented with saccharin sodium,but saccharin sodium was undetectable in the milk of goats receiving SS diet.In conclusion,administration of saccharin sodium was effective in increasing fat and energy corrected milk yield by increasing DMI and improving rumen fermentation and antioxidant capacity of dairy goats in summer.In addition,saccharin sodium residue was undetectable in the milk.

Automated identification of steel weld defects,a convolutional neural network improved machine learning approach

This paper proposes a machine-learning-based methodology to automatically classify different types of steel weld defects,including lack of the fusion,porosity,slag inclusion,and the qualified(no defects)cases.This methodology solves the shortcomings of existing detection methods,such as expensive equipment,complicated operation and inability to detect internal defects.The study first collected percussed data from welded steel members with or without weld defects.Then,three methods,the Mel frequency cepstral coefficients,short-time Fourier transform(STFT),and continuous wavelet transform were implemented and compared to explore the most appropriate features for classification of weld statuses.Classic and convolutional neural network-enhanced algorithms were used to classify,the extracted features.Furthermore,experiments were designed and performed to validate the proposed method.Results showed that STFT achieved higher accuracies(up to 96.63%on average)in the weld status classification.The convolutional neural network-enhanced support vector machine(SVM)outperformed six other algorithms with an average accuracy of 95.8%.In addition,random forest and SVM were efficient approaches with a balanced trade-off between the accuracies and the computational efforts.

Suppression of intervalley scattering and enhanced phonon anharmonic interactions in 2D Bi_(2)TeSe_(2):Crystal-field symmetry and band convergence

The electron-phonon(el-ph)and phonon-phonon interactions play a key role in determining electronic and thermal transport properties,respectively,in promising two-dimensional(2D)semiconductor de-vices.In this study,we investigated el-ph interactions using Wannier-Fourier interpolation method and renormalized phonon scattering considering finite-temperature effects in Bi_(2)TeSe_(2)monolayer.The re-sults show that the optical phonon modes dominate the carrier scattering,where level repulsion induced by crystal field splitting and spin-orbit coupling(SOC)effect effectively suppresses intervalley scattering,leading to high hole mobility.Moreover,the strong anharmonicity in Bi_(2)TeSe_(2)monolayer results in the temperature-dependent softening of its optical phonons,along with a corresponding variation in interatomic force constants(IFCs).As a result,the lattice thermal conductivity is remarkably low and exhibits weak temperature dependence.Finally,the predicted dimensionless thermoelectric figure of merit exceeds unity in the range of 200-800 K,indicating the potential of Bi_(2)TeSe_(2)monolayer for thermoelectric applications.This work provides new insights into the elimination of intervalley scat-tering by crystal field splitting and SOC effects,and paves the way for the evaluation of thermoelectric properties of materials with complex scattering mechanisms and strong anharmonicity.

天蓝色链霉菌海藻糖合酶的异源表达、活性分析及重组菌全细胞转化合成海藻糖的条件优化

从天蓝色链霉菌Streptomyces coelicolor克隆得到海藻糖合酶基因(ScTreS),在大肠杆菌Escherichia coli BL21(DE3)中进行了异源表达,通过Ni-NTA亲和柱对表达产物进行分离纯化得到纯酶,经SDS-PAGE测定其分子量约为62.3 kDa。研究其酶学性质发现该酶最适温度35℃;最适pH7.0,对酸性条件比较敏感。通过同源建模和序列比对分析,对该基因进行定点突变。突变酶K246A比酶活比野生酶提高了1.43倍,突变酶A165T相对提高了1.39倍,海藻糖转化率分别提高了14%和10%。利用突变体重组菌K246A进行全细胞转化优化海藻糖的合成条件并放大进行5L罐发酵,结果表明:在麦芽糖浓度300g/L、初始反应温度和pH分别为35℃和7.0的条件下,转化率最高达到71.3%,产量为213.93 g/L;当底物浓度增加到700g/L时,海藻糖产量仍可达到465.98g/L。