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.

Study on damage mechanism and damage distribution of the rear plate under impact of debris cloud

The debris cloud generated by the hypervelocity impact(HVI)of orbiting space debris directly threatens the spacecraft.A full understanding of the damage mechanism of rear plate is useful for the optimal design of protective structures.In this study,the hypervelocity yaw impact of a cylindrical aluminum projectile on a double-layer aluminum plate is simulated by the FE-SPH adaptive method,and the damage process of the rear plate under the impact of the debris cloud is analyzed based on the debris cloud structure.The damage process can be divided into the main impact stage of the debris cloud and the structural response of the rear plate.The main impact stage lasts a short time and is the basis of the rear plate damage.In the stage of structure response,the continuous deformation and inertial motion of the rear plate dominate the perforation of the rear plate.We further analyze the damage mechanism and damage distribution characteristics of the rear plate in detail.Moreover,the connection between velocity space and position space of the debris cloud is established,which promotes the general analysis of the damage law of debris cloud.Based on the relationship,the features of typical damage areas are identified by the localized fine analysis.Both the cumulative effect and structural response cause the perforation of rear plate;in the non-perforated area,cratering by the impact of hazardous fragments is the main damage mode of the rear plate.

The prognostic role of circulating tumor DNA across breast cancer molecular subtypes:A systematic review and meta-analysis

Objective:Circulating tumor DNA(ctDNA)is increasingly being used as a potential prognostic biomarker in cancer patients.We aimed to assess the prognostic value of ctDNA in different subtypes of breast cancer patients throughout the whole treatment cycle.Materials and methods:PubMed,Web of Science,Embase,Cochrane Library,Scopus,and clinical trials.gov databases were searched from January 2016 to May 2022.The following search terms were used:ctDNA OR circulating tumor DNA AND breast cancer OR breast carcinoma.Only studies written in English were included.The following pre-specified criteria should be met for inclusion:(i)original articles,conference abstracts,etc.;(ii)patients with breast cancer;(iii)ctDNA measurement;and(iv)clinical outcome data such as recurrence-free survival(RFS)and overall survival(OS).The random-effects model was preferred considering the potential het-erogeneity across studies.The main outcomes are ctDNA detection rate and postoperative long-term outcomes(RFS and OS).Results:A total of 24 studies were screened.At every measurement time,the ctDNA detection rate of the HR+subgroup was similar to that of the HR-subgroup(P=0.075;P=0.458;P=0.744;and P=0.578),and the ctDNA detection rate of the HER2+subgroup was similar to that of the HER2-subgroup(P=0.805;P=0.271;P=0.807;and P=0.703).In the HR+subgroup,RFS and OS of ctDNA positive patients were similar to those of ctDNA negative patients(P=0.589 and P=0.110),while RFS and OS of the ctDNA positive group was significantly shorter than those of the ctDNA negative patients in the HR-subgroup(HR=4.03,P<0.001;HR=3.21,P<0.001).According to HER grouping,the results were the same as above.In the triple negative breast cancer(TNBC)subgroup,the RFS and OS of ctDNA-positive patients was significantly shorter than of the ctDNA negative patients before and after surgery.Conclusions:ctDNA was more predictive of recurrence-free survival and overall survival in the HR-subgroup than in the HR+subgroup,and the same result was showed in the HER2-subgroup vs.HER2+subgroup.The prognosis of the TNBC subtype is closely related to ctDNA before and after surgery.

Circulating tumor DNA as prognostic markers of relapsed breast cancer:a systematic review and meta-analysis

Objective: Circulating tumor DNA (ctDNA) is increasingly being used as a potential prognosis biomarker in patients of breast cancer. This review aims to assess the clinical value of ctDNA in outcome prediction in breast cancer patients throughout the whole treatment cycle. Methods: PubMed, Web of Science, Embase, Cochrane Library, Scopus, and clinical trials.gov were searched from January 2016 to May 2022. Conference abstracts published in last three years were also included. The following search terms were used: ctDNA OR circulating tumor DNA AND breast cancer OR breast carcinoma. Only studies written in English languages were included. The following pre-specified criteria should be met for inclusion: (1) observational studies (prospective or retrospective), randomized control trials, case-control studies and case series studies;(2) patients with breast cancer;(3) ctDNA measurement;(4) clinical outcome data such as objective response rate (ORR), pathological complete response (pCR), relapse-free survival (RFS), overall survival (OS), and so on. The random-effect model was preferred considering the potential heterogeneity across studies. The primary outcomes included postoperative short-term outcomes (ORR and pCR) and postoperative long-term outcomes (RFS, OS, and relapse). Secondary outcomes focused on ctDNA detection rate. Results: A total of 30 studies, comprising of 19 cohort studies, 2 case-control studies and 9 case series studies were included. The baseline ctDNA was significantly negatively associated with ORR outcome (Relative Risk [RR] = 0.65, 95% confidence interval [CI]: 0.50–0.83), with lower ORR in the ctDNA-positive group than ctDNAnegative group. ctDNA during neoadjuvant therapy (NAT) treatment was significantly associated with pCR outcomes (Odds Ratio [OR] = 0.15, 95% CI: 0.04–0.54). The strong association between ctDNA and RFS or relapse outcome was significant across the whole treatment period, especially after the surgery (RFS: Hazard Ratio [HR] = 6.74, 95% CI: 3.73–12.17;relapse outcome: RR = 7.11, 95% CI: 3.05–16.53), although there was heterogeneity in these results. Pre-operative and post-operative ctDNA measurements were significantly associated with OS outcomes (pre-operative: HR = 2.03, 95% CI: 1.12–3.70;post-operative: HR = 6.03, 95% CI: 1.31–27.78). Conclusions: In this review, ctDNA measurements at different timepoints are correlated with evaluation indexes at different periods after treatment. The ctDNA can be used as an early potential postoperative prognosis biomarker in breast cancer, and also as a reference index to evaluate the therapeutic effect at different stages.

Debris cloud structure and hazardous fragments distribution under hypervelocity yaw impact

This study investigates how the debris cloud structure and hazardous fragment distribution vary with attack angle by simulating a circular cylinder projectile hypervelocity impinging on a thin plate using the finite element-smoothed particle hydrodynamics(FE-SPH)adaptive method.Based on the comparison and analysis of the experimental and simulation results,the FE-SPH adaptive method was applied to address the hypervelocity yaw impact problem,and the variation law of the debris cloud structure with the attack angle was obtained.The screening criterion of the hazardous fragment at yaw impact is given by analyzing the debris formation obtained by the FE-SPH adaptive method,and the distribution characteristics of hazardous fragments and their relationship with the attack angle are given.Moreover,the velocity space was used to evaluate the distribution range and damage capability of asymmetric hazardous fragments.The maximum velocity angle was extended from fully symmetrical working conditions to asymmetrical cases to describe the asymmetrical debris cloud distribution range.In this range,the energy density was calculated to quantitatively analyze how much damage hazardous fragments inflict on the rear plate.The results showed that the number of hazardous fragments generated by the case near the 35°attack angle was the largest,the distribution range was the smallest,and the energy density was the largest.These results suggest that in this case,debris cloud generated by the impact had the strongest damage to the rear plate.

Research on the Electric Energy Metering Data Sharing Method in Smart Grid Based on Blockchain

Enabling data sharing among smart grid power suppliers is a pressing challenge due to technical hurdles in verifying,storing,and synchronizing energy metering data.Access and sharing limitations are stringent for users,power companies,and researchers,demanding significant resources and time for permissions and verification.This paper proposes a blockchain-based architecture for secure and efficient sharing of electric energy metering data.Further,we propose a data sharing model based on evolutionary game theory.Based on the Lyapunov stability theory,the model’s evolutionary stable strategy(ESS)is analyzed.Numerical results verify the correctness and practicability of the scheme proposed in this paper,and provide a new method for realizing convenient,safe and fast data sharing.

5G通信技术在城市轨道交通信号车地通信中的应用研究

论文研究了5G通信技术在城市轨道交通信号车地通信中的应用。首先介绍了5G通信技术的特点和发展历程,以及在城市轨道交通信号车地通信中的现状。接着针对5G通信技术在城市轨道交通信号车地通信中的优势,提出了5G通信技术在城市轨道交通信号车地通信中的应用方案,并进行了实验研究。论文对于推动城市轨道交通信号车地通信的发展具有重要意义。

配送式智能变电站关键技术研究

配送式变电站[1]是一种新兴的变电站建设方案,目前已开始在新一代智能变电站的建设中采用。本文主要介绍预制舱式智能变电站[2],文章从预制舱结构及电气接口上探讨了预制舱式智能变电站的二次系统的几项关键技术,着重分析了预制舱的结构、屏柜布局以及预制舱的配置方案,并对预制舱式变电站的电气接口形式进行了研究。

柠檬酸化壳寡糖改性水性聚氨酯的合成与性能

以异佛尔酮二异氰酸酯(IPDI)与聚四氢呋喃醚二醇(PTMG-2000)为主要原料,二羟甲基丙酸(DMPA)为亲水扩链剂,柠檬酸化壳寡糖(CA-COS)为改性剂,合成了柠檬酸化壳寡糖型水性聚氨酯(CCOS-WPU)。以乳液和胶膜的基本性能为指标,对反应条件进行了优化,通过傅里叶变换红外光谱对胶膜的结构进行了表征,用X射线衍射和热重分析对胶膜的结晶度和热稳定性进行了分析。结果表明,当n(NCO)∶n(OH)为4∶1,DMPA用量为5.0%,CA-COS用量为1.0%时,CCOS-WPU乳液粒径为57.57 nm,CCOS-WPU乳液及胶膜的综合性能较好,相比未改性的WPU,胶膜的拉伸强度从15.84 MPa提高到16.34 MPa,CA-COS的加入可使聚氨酯的结晶能力下降,耐热性明显提高。

Erucic acid from Isatis indigotica Fort. suppresses influenza A virus replication and inflammation in vitro and in vivo through modulation of NF-kB and p38 MAPK pathway

Isatis indigotica Fort.(Ban-Lan-Gen)is an herbal medicine prescribed for influenza treatment.However,its active components and mode of action remain mostly unknown.In the present study,erucic acid was isolated from Isatis indigotica Fort.,and subsequently its underlying mechanism against influenza A virus(IAV)infection was investigated in vitro and in vivo.Our results demonstrated that erucic acid exhibited broad-spectrum antiviral activity against IAV resulting from reduction of viral polymerase transcription activity.Erucic acid was found to exert inhibitory effects on IAV or viral(v)RNA-induced pro-inflam-matory mediators as well as interferons(IFNs).The molecular mechanism by which erucic acid with antiviral and anti-inflammatory properties was attributed to inactivation of NF-kB and p38 MAPK signaling.Furthermore,the NF-kB and p38 MAPK inhibitory effect of erucic acid led to diminishing the transcriptional activity of interferon-stimulated gene factor 3(ISGF-3),and thereby reducing IAV-triggered pro-inflammatory response amplification in IFN-β-sensitized cells.Additionally,IAV-or vRNA-triggered apoptosis of alveolar epithelial A549 cells was prevented by erucic acid.In vivo,erucic acid administration consistently displayed decreased lung viral load and viral antigens expression.Meanwhile,erucic acid markedly reduced CD8+cytotoxic T lymphocyte(CTL)recruitment,pro-apoptotic signaling,hyperactivity of multiple signaling pathways,and exacerbated immune inflammation in the lung,which resulted in decreased lung injury and mortality in mice with a mouse-adapted A/FM/1/47-MA(H1N1)strain infection.Our findings provided a mechanistic basis for the action of erucic acid against IAV-mediated inflammation and injury,suggesting that erucic acid may have a therapeutic potential in the treatment of influenza.

Oblique perforation of thick metallic plates by rigid projectiles

Oblique perforation of thick metallic plates by rigid projectiles with various nose shapes is studied in this paper. Two perforation mechanisms, i.e., the hole enlargement for a sharp projectile nose and the plugging formation for a blunt projectile nose, are considered in the proposed analytical model. It is shown that the perforation of a thick plate is dominated by several non-dimensional numbers, i.e., the impact function, the geometry function of projectile, the non-dimensional thickness of target and the impact obliquity. Explicit formulae are obtained to predict the ballistic limit, residual velocity and directional change for the oblique perforation of thick metallic plates. The proposed model is able to predict the critical condition for the occurrence of ricochet. The proposed model is validated by comparing the predictions with other existing models and independent experimental data.

A simplified approximate model of compressible hypervelocity penetration

A simplified approximate model considering rod/target material's compressibility is proposed for hypervelocity penetration.We study the effect of shockwaves on hypervelocity penetration whenever the compressibility of the rod is much larger,analogously,and much less than that of the target,respectively.The results show that the effect of shockwaves is insignificant up to 12 km/s,so the shockwave is neglected in the present approximate model.The Murnaghan equation of state is adopted to simulate the material behaviors in penetration and its validity is proved.The approximate model is finally reduced to an equation depending only on the penetration velocity and a simple approximate solution is achieved.The solution of the approximate model is in agreement with the result of the complete compressible model.In addition,the effect of shockwaves on hypervelocity penetration is shown to weaken material's compressibility and reduce the interface pressure of the rod/target,and thus the striking/protective performance of the rod/target is weakened,respectively.We also conduct an error analysis of the interface pressure and penetration efficiency.With a velocity change of 1.6 times the initial sound speed for the rod or target,the error of the approximate model is very small.For metallic rod-target combinations,the approximate model is applicable even at an impact velocity of 12 km/s.

α7-烟碱型乙酰胆碱受体在肺炎和肺癌中的研究进展

烟碱型乙酰胆碱受体(nicotinic acetylcholine receptors,nAChRs)是细胞膜上门控离子通道受体,乙酰胆碱(acetylcholine,ACh)与其相互作用,激活细胞增殖、凋亡等下游信号通路,参与肺组织多种病理生理过程,在肺癌的发生发展过程中发挥重要作用。α7-nAChR是nAChRs的重要亚型,通过胆碱能抗炎通路对肺炎产生重要影响,还可以参与肺癌细胞增殖、血管生成、转移以及抑制细胞凋亡等过程。尼古丁作为α7-nAChR的激动剂,其调节机制研究对肺癌药物的研发具有重要意义。本文将对α7-nAChR及其下游信号通路在肺炎和肺癌中的作用进行综述,为制定抗炎策略和研究新型抗癌药物提供依据。

聚丙烯-聚乙烯消光膜体系织态结构形成机理

采用偏光显微镜和热台联用的方法,研究了聚丙烯(PP)-聚乙烯(PE)共混体系降温过程中的相分离和结晶行为。在此共混体系中,PE质量分数为10%~60%,随着PE质量分数增加,结果呈现2种不同的分相形貌特征:PE质量分数为10%~30%时,PE相区分散在连续相PP中,当PE质量分数为40%~60%时,PE/PP共存,为双连续相。通过对结晶过程形貌特征的转变以及相畴尺寸的定量分析,发现了2种控制表面粗糙程度的机理:在PP为单连续相时,粗糙度主要取决于分散相相畴大小;在PE/PP双连续相的情况下,在互穿网络结构中主要为骨架相互挤压控制。通过比对各拉伸比下的形貌特征,发现静态结晶形成的织态结构在拉伸过程中发生与宏观应变相关的等比放大,表明消光膜表面形貌主要取决于静态结晶过程。为了建立静态结晶形成结构和消光膜雾度的关系,通过共混-挤出-流延-双向拉伸的方法制备了不同PE含量所对应的消光膜样品,通过雾度测试,证明表面粗糙的织态结构为决定雾度的关键,同时证明了静态结晶实验对于消光膜加工过程中雾度控制的指导意义。

Preface to the special collection of Induced Earthquakes

It has been long recognized that a variety of anthropogenic activities may cause earthquakes(Ellsworth et al.,2013;Yang HF et al.,2017).In the recent decades,induced earthquakes have been found in many settings and become a growing concern,in particular for regions that are undergoing with resource development.

Chronic pre-treatment with memantine prevents amyloid-beta protein-mediated long-term potentiation disruption

Previous studies indicate that memantine, a low-affinity N-methyI-D-aspartate receptor antagonist exerted acute protective effects against amyloid-β protein-induced neurotoxicity. In the present study, the chronic effects and mechanisms of memantine were investigated further using electrophysiological methods. The results showed that 7-day intraperitoneal application of memantine, at doses of 5 mg/kg or 20 mg/kg, did not alter hippocampal long-term potentiation induction in rats, while 40 mg/kg memantine presented potent long-term potentiation inhibition. Then further in vitro studys were carried out in 5 mg/kg and 20 mg/kg memantine treated rats. We found that 20 mg/kg memantine attenuated the potent long-term potentiation inhibition caused by exposure to amyloid-β protein in the dentate gyrus in vitro. These findings are the first to demonstrate the antagonizing effect of long-term systematic treatment of memantine against amyloid-β protein triggered long-term potentiation inhibition to improve synaptic plasticity.

Phytosterols in edible oil:Distribution,analysis and variation during processing

Phytosterols,which are naturally occurring in plants,have excellent nutritional and health values on lowering both the blood cholesterol level and the risk of cardiovascular diseases.Edible oils are the main source of daily intake of phytosterols,whereas the properties of phytosterols may vary a lot depending on their sources.During the processing of edible oil including refining and frying,phytosterol's content fluctuates,which influences the properties of the final product.Phytosterols and their derivatives undergo physical migration between different phases and chemical conversion during the processing,which reduces the quality and the commercial value of edible oils.Therein,the loss of phytosterols is the major concern in the process of neutralization and deodorization.In addition,oxidation and thermal degradation of phytosterols occur simultaneously during frying,which also reduces the content of phytosterols.Nevertheless,the oil matrix has a promoting or an inhibitory effect on the thermal oxidation of phytosterols.Therefore,various efforts have been devoted to analyzing and improving the remaining contents of phytosterols in edible oil.Regardless of the processing method,temperature plays an important role in the loss of phytosterols.At present,themain analysismethods of phytosterols include gas chromatography and liquid chromatography,inwhich the pretreatment of different types of phytosterols is also a crucial step.This review focused on the following topics comprehensively:(i)the distribution of phytosterols in the oil-containing plants and edible oils during the refining processing;(ii)the pretreatment and analysis methods of various phytosterols(free phytosterols,phytosteryl fatty acid esters,phytosteryl glycosides and acylated phytosteryl glycosides);(iii)the variation of phytosterols in process of esterification and oxidation,storage and so on.The study also proposed that the investigation in the loss and safety of phytosterols during processing of the vegetable oils should be proceeded further in combination with efficient and accurate chromatography methods.

Spatial Quantitative Analysis of Garlic Price Data Based on ArcGIS Technology

In order to solve the hidden regional relationship among garlic prices,this paper carries out spatial quantitative analysis of garlic price data based on ArcGIS technology.The specific analysis process is to collect prices of garlic market from 2015 to 2017 in different regions of Shandong Province,using the Moran's Index to obtain monthly Moran indicators are positive,so as to analyze the overall positive relationship between garlic prices;then using the geostatistical analysis tool in ArcGIS to draw a spatial distribution Grid diagram,it was found that the price of garlic has a significant geographical agglomeration phenomenon and showed a multi-center distribution trend.The results showed that the agglomeration centers are Jining,Dongying,Qingdao,and Yantai.At the end of the article,according to the research results,constructive suggestions were made for the regulation of garlic price.Using Moran’s Index and geostatistical analysis tools to analyze the data of garlic price,which made up for the lack of position correlation in the traditional analysis methods and more intuitively and effectively reflected the trend of garlic price from low to high from west to east in Shandong Province and showed a pattern of circular distribution.

Synthesis of palladium-rhodium bimetallic nanoparticles for formic acid dehydrogenation

Herein,we report for the first time the synthesis of preformed bimetallic Pd-Rh nanoparticles with different Pd:Rh ratios(nominal molar ratio:80-20,60-40,40-60,20-80) and the corresponding Pd and Rh monometallic ones by sol immobilization using polyvinyl alcohol(PVA) as protecting agent and NaBH4 as reducing agent,using carbon nanofibers with high graphitization degree(HHT) as the desired support.The synthesized catalysts were characterized by means of Transmission Electron Microscopy(TEM) and inductively coupled plasma optical emission spectroscopy(ICP-OES).TEM shows that the average particle size of the Pd-Rh nanoparticles is the range of 3-4 nm,with the presence of few large agglomerated nanoparticles.For bimetallic catalysts,EDX-STEM analysis of individual nanoparticles demonstrated the presence of random-alloyed nanoparticles even in all cases Rh content is lower than the nominal one(calculated Pd:Rh molar ratio:90-10,69-31,49-51,40-60).The catalytic performance of the Pd-Rh catalysts was evaluated in the liquid phase dehydrogenation of formic acid to H2.It was found that Pd-Rh molar ratio strongly influences the catalytic performance.Pd-rich catalysts were more active than Rh-rich ones,with the highest activity observed for Pd90:Rh10(1792 h^(-1)),whereas Pd69:Rh31(921 h^(-1)) resulted the most stable during recycling tests.Finally,Pd90:Rh10 was chosen as a representative sample for the liquid-phase hydrogenation of muconic acid using formic acid as hydrogen donor,showing good yield to adipic acid.

A facile one-pot hydrothermal synthesis as an efficient method to modulate the potassium content of cryptomelane and its effects on the redox and catalytic properties

Cryptomelane has been widely applied as catalyst in oxidation reactions due to its excellent redox properties and low cost.Here,a novel one-pot hydrothermal synthesis using a potassium permanganate aqueous solution as precursor and ethanol as reducing agent has successfully been developed to obtain cryptomelane nano-oxides.This synthetic route makes it possible to control the amount of potassium incorporated into the structure of the cryptomelane by selecting the appropriate synthesis temperature and ethanol initial concentration.Taking advantage of this approach,the effect of potassium concentration on the structural stability and reducibility of the cryptomelane,which are poorly discussed in the literature,has been studied.We have observed that samples with low content of potassium(~11%)show high conversions of CO to CO2 especially at low temperatures.The lower activity of the samples with high K contents(~16%)can be ascribed to the beneficial effect of K on the structural stability of cryptomelane in detriment of labile oxygen on cryptomelane surface.