Machine learning optimization strategy of shaped charge liner structure based on jet penetration efficiency

Shaped charge liner(SCL)has been extensively applied in oil recovery and defense industries.Achieving superior penetration capability through optimizing SCL structures presents a substantial challenge due to intricate rate-dependent processes involving detonation-driven liner collapse,high-speed jet stretching,and penetration.This study introduces an innovative optimization strategy for SCL structures that employs jet penetration efficiency as the primary objective function.The strategy combines experimentally validated finite element method with machine learning(FEM-ML).We propose a novel jet penetration efficiency index derived from enhanced cutoff velocity and shape characteristics of the jet via machine learning.This index effectively evaluates the jet penetration performance.Furthermore,a multi-model fusion based on a machine learning optimization method,called XGBOOST-MFO,is put forward to optimize SCL structure over a large input space.The strategy's feasibility is demonstrated through the optimization of copper SCL implemented via the FEM-ML strategy.Finally,this strategy is extended to optimize the structure of the recently emerging CrMnFeCoNi high-entropy alloy conical liners and hemispherical copper liners.Therefore,the strategy can provide helpful guidance for the engineering design of SCL.

Influence of O-O formation pathways and charge transfer mediator on lipid bilayer membrane-like photoanodes for water oxidation

Inspired by the function of crucial components in photosystemⅡ(PSⅡ),electrochemical and dyesensitized photoelectrochemical(DSPEC)water oxidation devices were constructed by the selfassembly of well-designed amphipathic Ru(bda)-based catalysts(bda=2,2'-bipyrdine-6,6'-dicarbonoxyl acid)and aliphatic chain decorated electrode surfaces,forming lipid bilayer membrane(LBM)-like structures.The Ru(bda)catalysts on electrode-supported LBM films demonstrated remarkable water oxidation performance with different O-O formation mechanisms.However,compared to the slow charge transfer process,the O-O formation pathways did not determine the PEC water oxidation efficiency of the dyesensitized photoanodes,and the different reaction rates for similar catalysts with different catalytic paths did not determine the PEC performance of the DSPECs.Instead,charge transfer plays a decisive role in the PEC water oxidation rate.When an indolo[3,2-b]carbazole derivative was introduced between the Ru(bda)catalysts and aliphatic chain-modified photosensitizer in LBM films,serving as a charge transfer mediator for the tyrosine-histidine pair in PSⅡ,the PEC water oxidation performance of the corresponding photoanodes was dramatically enhanced.

高速艇发电机高温报警停机问题分析及处理

主要针对某高速艇在航速到达45节以上时出现发电机高温停机问题,通过现场勘验以及与相关方研讨分析,分析问题产生的原因,并制定了解决措施。为确保既满足给发电机供水降温又能避免损坏发电机,调整了发电机冷却水舷外吸口的布置方案,在经过多次航行试验验证后,最终解决了发电机高温停机问题。

高速铝合金艇船体共振原因分析及对策

主要针对某高速铝合金艇在试验过程中航速到达45节以上时出现严重的振动问题,经过观察、听音、测量、计算、分析等手段排除疑似原因并逐步确定振动原因和振源位置,并根据振源部位进行共振消除方案分析和实际应用试验,最终找到合理可行消除共振的方案,通过长时间、高航速的航行试验最终证实问题分析合理、方案可行、减振措施得当且效果显著。

Bioinformatics and Expression Analysis of CaERF Gene in Capsicum

AP2/ERF transcription factor is a kind of plant-specific transcription factor,which is widely involved in the whole process of plant growth and development,and has important regulatory effects in plant secondary metabolism.In this study,the CaERF gene was cloned from Capsicum annuum by RT-PCR.The bioinformatics and expression analysis revealed that the CDS region of this gene is 795 bp in length,encoding 264 amino acids,and the molecular weight and isoelectric point of the protein are 30.1 KD and 5.74,respectively;the gene encodes a 58-amino acid DNA-binding domain AP2 at 533-706,which is closest to Capsicum chinense in genetics;and the gene is expressed early in the fruit development from 16 to 20 d after flowering,and related to the level of pun 1 gene expression.The cloning and expression analysis of CaERF transcription factor gene laid a foundation for further study on the regulation of capsaicin synthesis.

Analysis of Cloning and Expression Characteristics of Capsicum chinense Jacq. CcMYB Gene

In order to discuss the role of MYB gene in capsaicine synthesis process, one CcMYB gene was cloned from Capsicum chinense Jacq. by RT-PCR. Its cDNA has a total length of 1 038 bp, and was speculated to code 345 amino acids, comprising an complete open reading frame. The isoelectric point is 8.57, and the molecular weight is 38.2 KD. The protein is a neutral hydrophobin without transmentbrane structure. There are two MYBDNA domains at the N terminal. The fluorescence quantitative PCR results showed that CcMYB gene was expressed in all the root, stem, leaf, flower, placenta and fruit tissue of pepper, and the expression level was the highest in fruit ; and CcMYB was expressed in fruit at the highest level at turning stage, and at the second highest level at expansion stage, which accords with the expression profile of punl gene in fruit development period. It is speculated that CcMYB gene plays an important role in the regulation of capsaicine synthesis in C. chinense fruit.

Polymeric viologen-based electron transfer mediator for improving the photoelectrochemical water splitting on Sb_(2)Se_(3) photocathode

The photogenerated charge carrier separation and transportation of inside photocathodes can greatly influence the performance of photoelectrochemical(PEC)H2 production devices.Coupling TiO_(2) with p-type semiconductors to construct heterojunction structures is one of the most widely used strategies to facilitate charge separation and transportation.However,the band position of TiO_(2) could not perfectly match with all p-type semiconductors.Here,taking antimony selenide(Sb_(2)Se_(3))as an example,a rational strategy was developed by introducing a viologen electron transfer mediator(ETM)containing polymeric film(poly-1,1′-dially-[4,4′-bipyridine]-1,1′-diium,denoted as PV^(2+))at the interface between Sb_(2)Se_(3) and TiO_(2) to regulate the energy band alignment,which could inhibit the recombination of photogenerated charge carriers of interfaces.With Pt as a catalyst,the constructed Sb_(2)Se_(3)/PV^(2+)/TiO_(2)/Pt photocathode showed a superior PEC hydrogen generation activity with a photocurrent density of−18.6 mA cm^(-2) vs.a reversible hydrogen electrode(RHE)and a half-cell solar-to-hydrogen efficiency(HC-STH)of 1.54%at 0.17 V vs.RHE,which was much better than that of the related Sb_(2)Se_(3)/TiO_(2)/Pt photocathode without PV^(2+)(−9.8 mA cm^(-2),0.51%at 0.10 V vs.RHE).

UltrahighQ Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)microwave dielectric ceramics for temperature-stable millimeter-wave dielectric resonator antennas

Microwave dielectric ceramics should be improved to advance mobile communication technologies further.In this study,we prepared Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics with nonstoichiometric Sr^(2+)ratios based on our previously reported SrY_(2)O_(4) microwave dielectric ceramic,which has a low dielectric constant and an ultrahigh quality factor(Q value).The ceramic exhibited a 33.6% higher Q-by-frequency(Q×f)value(Q≈12,500)at x=0.02 than SrY_(2)O_(4).All Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited pure phase structures,although variations in crystal-plane spacings were observed.The ceramics are mainly composed of Sr-O,Y1-O,and Y_(2)-O octahedra,with the temperature coefficient of the resonant frequency(τ_(f))of the ceramic increasing with Y_(2)-O octahedral distortion.The ceramic comprises uniform grains with a homogeneous elemental distribution,clear grain boundaries,and no obvious cavities at x=0.02.The Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited good microwave dielectric properties,with optimal performance observed at x=0.02(dielectric constant(εr)=15.41,Q×f=112,375 GHz,and τ_(f)=-17.44 ppm/℃).The τ_(f) value was reduced to meet the temperaturestability requirements of 5G/6G communication systems by adding CaTiO_(3),with Sr_(1.02)Y_(2)O_(4.02)+2wt% CaTiO_(3) exhibiting ε_(r)=16.14,Q×f=51,004 GHz,andτf=0 ppm/℃.A dielectric resonator antenna prepared using Sr_(1.02)Y_(2)O_(4.02)+2wt%CaTiO_(3) exhibited a central frequency of 26.6 GHz,with a corresponding gain and efficiency of 3.66 dBi and 83.14%,respectively.Consequently,Sr_(1.02)Y_(2)O_(4).02-based dielectric resonator antennas are suitable for use in 5G millimeter-wave band(24.5-27.5 GHz)applications.

Promoting near-infrared II fluorescence efficiency by blocking long-range energy migration

Generally,long wavelength absorbed near-infrared II(NIR-II)dyes have a low fluorescence efficiency in aggregate states for aggregate-caused quenching effect,simultaneously enhancing efficiency and extending absorption is a challenging issue for NIR-II dyes.Here,three benzo[1,2-c:4,5-c’]bis[1,2,5]thiadiazole(BBT)derivatives(TPA-BBT,FT-BBT,and BTBT-BBT)are used to clarify fluorescence quenching mechanisms.When the BBT derivatives are doped into a small molecule matrix,they show quite different fluorescence behaviors.Structuredistorted TPA-BBT displays fluorescence quenching originating from short-range exchange interaction,while FT-BBT and BTBT-BBT with a co-planar-conjugated backbone exhibit concentration-dependent quenching processes,namely changing from long-range dipole-dipole interaction to exchange interaction,which could be majorly ascribed to large spectral overlap between absorption and emission.By precisely tuning doping concentration,both FT-BBT and BTBT-BBT nanoparticles(NPs)present the optimal NIR-II fluorescence brightness at∼2.5 wt%doping concentration.The doped NPs have good biocompatibility and could be served as fluorescence contrast agents for vascular imaging with a high resolution under 980-nm laser excitation.Those paradigms evidence that molecular doping can promote fluorescence efficiency of long wavelength-absorbed NIR-II fluorophores via suppressing long-range energy migration.

Evaluation of activated sludge properties’changes in industrial-wastewater pre-treatment:role of residual aluminum hydrolyzed species with different polymerization degree

With the widespread introduction of pre-coagulation prior to the biological unit in various industrial wastewater treatments,it is noteworthy that long-term accumulation of residual coagulants has certains effect on both micro and macro characteristics of activated sludge(AS).In this study,the morphology distributions of residual aluminum salts(RAS)and their effects on the removal efficiency of AS were investigated under different PAC concentrations.The results showed that the dominance of medium polymeric RAS,formed under an appropriate PAC dose of 20 mg/L enhanced the hydrophobicity,flocculation,and sedimentation performances of AS,as well as the enzymatic activity in cells in the sludge system,improving the main pollutants removal efficiency of the treatment system.Comparatively the species composition with monomer and dimer/high polymer RAS as the overwhelming parts under an over-dosed PAC concentration of 55 mg/L resulted in excessive secretion of EPS with loose flocs structure and conspicuous inhibition of cellular activity,leading to the deterioration of physico-chemical and biological properties of AS.Based on these findings,this study can shed light on the role of the RAS hydrolyzed species distributions,closely relevant to Al dosage,in affecting the comprehensive properties of AS and provide a theoretical reference for coagulants dosage precise control in the pretreatment of industrial wastewater.

Design and evaluation of a novel biopsy needle with hemostatic function

Biopsy is a method commonly used for early cancer diagnosis.However,bleeding complications of widely available biopsy are risky for patients.Safer biopsy will result in a more accurate cancer diagnosis and a decrease in the risk of complications.In this article,we propose a novel biopsy needle that can reduce bleeding during biopsy procedures and achieve stable hemostasis.The proposed biopsy needle features a compact structure and can be operated easily by left and right hands.A predictive model for puncture force and tip deflection based on coupled Eulerian–Lagrangian(CEL)method is developed.Experimental results show that the biopsy needle can smoothly deliver the gelatin sponge hemostatic plug into the tissue.Although the hemostatic plug bends,the overall delivery process is stable,and the hemostatic plug retains in the tissue without being affected by the withdrawal of the needle.Further experiments indicate that the specimens are well obtained and evenly distributed in the groove of the outer needle without scattering.Our proposed design of biopsy needle possesses strong ability of hemostasis,tissue cutting,and tissue retention.The CEL model accurately predicts the peak of puncture force and produces close estimation of the insertion force at the postpuncture stage and tip position.

Switching the O-O Bond Formation Pathways of Ru-pda Water Oxidation Catalyst by Third Coordination Sphere Engineering

Water oxidation is a vital anodic reaction for renewable fuel generation via electrochemical-and photoelectrochemical-driven water splitting or CO_(2)reduction.Ruthenium complexes,such as Ru-bda family,have been shown as highly efficient wateroxidation catalysts(WOCs),particularly when they undergo a bimolecular O-O bond formation pathway.In this study,a novel Ru(pda)-type(pda^(2–)=1,10-phenanthroline-2,9-dicarboxylate)molecular WOC with 4-vinylpyridine axial ligands was immobilized on the glassy carbon electrode surface by electrochemical polymerization.Electrochemical kinetic studies revealed that this homocoupling polymer catalyzes water oxidation through a bimolecular radical coupling pathway,where interaction between two Ru(pda)–oxyl moieties(I2M)forms the O-O bond.The calculated barrier of the I2M pathway by densityfunctional theory(DFT)is significantly lower than the barrier of a water nucleophilic attack(WNA)pathway.By using this polymerization strategy,the Ru centers are brought closer in the distance,and the O-O bond formation pathway by the Ru(pda)catalyst is switched from WNA in a homogeneous molecular catalytic system to I2M in the polymerized film,providing some deep insights into the importance of third coordination sphere engineering of the water oxidation catalyst.

Effect of rare earth on the performance of Ru/MgAl-LDO catalysts for ammonia synthesis

A series of MgAl-layered double oxides（LDO） doped with different rare-earth elements（Y, La, and Ce）were synthesized by the calcination of Mg-Al layered double hydroxides, and Ru, which were used to prepare ammonia synthesis catalysts. The as-obtained oxides and catalysts were characterized by XRD,TEM, TPD, TPR and XPS to understand their catalytic performances in ammonia synthesis. The H_2-TPR and HRTEM studies reveal that Ru/Y-LDO catalyst possesses more active Ru metal and small particle size.The XPS demonstrates that the electronic interaction between Y and Ru metals is stronger, which can be tentatively explained by most of Y inserted into the hydrotalcites structure. CO_2-TPD demonstrates that Ru/Y-LDO catalyst shows stronger basic site densities than catalysts doped with Ce and La. Higher activity of the Ru/Y-LDO catalyst can be attributed to smaller particle size, more active metal（Ru） and strong Ru-support interaction.

Multilevel air quality evolution in Shenyang:Impact of elevated point emission reduction

Visibility observed at different altitudes is favorable to understand the causes of air pol-lution.We conducted 4-years of observations of visibility at 2.8 and 60 m and particulate matter(PM)concentrations from 2015 to 2018 in Shenyang,a provincial city in Northeast China.The results indicated that visibility increased with the increasing height in winter(especially at night),and decreased with height in summer(especially at the daytime).PM concentration exhibited opposite vertical variation to visibility,reflecting that visibility de-grades with the increase of aerosol concentration in the air.The radiosonde meteorological data showed that weak turbulence in the planetary boundary layer(PBL)in winter favored aerosols'accumulation near the surface.Whereas in summer,unstable atmospheric con-ditions,upper-level moister environment,and regional transport of air pollutants resulted in the deterioration of upper-level visibility.Inter-annual variation in the two-level visibility indicated that the upper-level visibility improved more significantly than low-level visibil-ity,much likely due to the reduction in emission of elevated point sources in Shenyang.Our study suggested that strengthening the control of surface non-point emissions is a promis-ing control strategy to improve Shenyang air quality.