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Effect of neutral polymeric bonding agent on tensile mechanical properties and damage evolution of NEPE propellant

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Defence Technology（防务技术） 2024年第2期32卷 357-367页

作者： M.wubuliaisan Yanqing wu xiao Hou Kun Yang Hongzheng Duan Xinmei Yin State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China The Fourth Institute of China Aerospace Science and Technology Corporation Xi'an710025PR China School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081PR China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyHubei441003PR China

Introducing Neutral Polymeric bonding agents(NPBA) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could improve the adhesion between filler/matrix interface, thereby contributing to the development of new generations of the NEPE propellant with better mechanical properties. Therefore,understanding the effects of NPBA on the deformation and damage evolution of the NEPE propellant is fundamental to material design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different amounts of NPBA. The damage evolution in terms of interface debonding is further investigated using a cohesive-zone model(CZM). Experimental results show that the initial modulus and strength of the NEPE propellant increase with the increasing amount of NPBA while the elongation decreases. Meanwhile, the relaxation rate slows down and a higher long-term equilibrium modulus is reached. Experimental and numerical analyses indicate that interface debonding and crack propagation along filler-matrix interface are the dominant damage mechanism for the samples with a low amount of NPBA, while damage localization and crack advancement through the matrix are predominant for the ones with a high amount of NPBA. Finally, crosslinking density tests and simulation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

关键词： Solid propellant Bonding agent Mechanical properties Damage evolution Cohesive-zone model Interface debonding

Climatic impacts induced by winter wheat irrigation over North China simulated by the nonhydrostatic RegCM4.7

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Advances in Climate Change Research 2024年第2期15卷 197-210页

作者： Jia wu Zhen-Yu HAN Xue-Jie gao Zheng-Jia LIU National Climate Centre China Meteorological AdministrationBeijing 100081China Key Laboratory for Climate Studies China Meteorological AdministrationBeijing 100081China Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China

Quantification of the impact of winter wheat irrigation on the climate and the occurrence of extreme climatic events over North China is crucial for regional adaptation *** related studies mainly focused on the impact on surface processes;however,few focused on the effects of extreme events using high-resolution nonhydrostatic regional climate ***,the 9-km-resolution nonhydrostatic RegCM4.7 was coupled with a crop irrigation scheme and an updated winter wheat irrigation dataset to better simulate irrigation *** experiments were conducted with and without winter wheat irrigation to isolate the effects of *** showed that irrigation simulation reduces the model biases in temperature,precipitation,latent heat flux,soil moisture,sensitive heat flux,and top-layer soil ***,it also reduces the bias and increases the correlation with observations obtained in irrigated areas,especially in summer,indicating better representation of irrigation *** wheat irrigation tends to cause substantial cooling of the local surface maximum,minimum,and mean air temperatures(by-1.68,-0.34,and-0.79℃,respectively)over irrigated areas of North China,with the largest changes observed in relation to maximum ***,precipitation is found to increase during spring and summer,which is strongly related to water vapor transport in the lower levels of the *** analyses indicated that the number of annual mean hot days decrease(-13.9 d),whereas the number of both comfort days(+10.2 d)and rainy days(days with total precipitation greater than 1 mm:+6.6 d)increase over irrigated areas,demonstrating beneficial feedback to human perception and ***,although the heat wave risk increases(number of annual mean heat wave days:+5.8 d),the impact is limited to small areas within irrigated ***,no notable change was found in terms of heavy rainfall events and precipitation intensity

关键词： Nonhydrostatic regional climate model Irrigation effect Extreme events North China

PACS gene family-related neurological diseases: limited genotypes and diverse phenotypes

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World Journal of Pediatrics 2024年第1期20卷 82-91页

作者： Han Zhang Kai gao Shuang Wang Yue-Hua Zhang Zhi-Xian Yang Ye wu Yu-wu Jiang Department of Pediatrics Peking University First Hospital.No.1 Xi'an Men StreetWest DistrictBeijing 100034China Bejing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases BeijingChina Children Epilepsy Center Peking University First HospitalBeijingChina Key Laboratory for Neuroscience Ministry of Education/National Health and Family Planning CommissionPeking UniversityBeijingChina Center of Epilepsy Beijing Institute for Brain DisordersBeijingChina

Background The PACS gene family has been demonstrated to be related to intracellular vesicular *** phenotypic manifestations caused by the pathogenic variants of PACS include epilepsy,intellectual disability/developmental delay,and malformations,such as facial *** We identified seven new cases with pathogenic or likely pathogenic PACS variants using next-generation *** information obtained from these patients was analyzed along with that obtained from previously reported *** With the inclusion of the newly diagnosed cases in this study,103 cases with PACS gene family-related neurological diseases were reported,of which 43 were PACS2-related cases and the remaining were PACSI-related *** patients had seizures,which have been reported to be effectively controlled by several types of anti-seizure medications(ASMs).The most efficacious and frequently prescribed ASMs included sodium valproate(43.3%,13/30),oxcarbazepine/carbamazepine(26.7%,8/30),and levetiracetam(20%,6/30).Almost all patients had intellectual disability/developmental *** most common pathogenic missense variants were PACSI ***203Trp and PACS2 *** addition,we report a patient carrying a likely pathogenic copy number variation(CNV)(de novo heterozygous deletion of chr14:105821380-106107443,286 kilobase,destroyed part of the furin-binding region domain and the protein structure after it)with more severe and refractory late-onset *** The clinical phenotypes of the different PACS heterozygous missense variants were *** pathogenic variant sites of PACSI and PACS2 were quite limited but located in different regions.A CNV destroying part of the PACS2 gene might also be *** findings may provide an important clue for further functional studies on the pathogenic mechanism of neurological disorders related to the PACS gene family.

关键词： Developmental delay Epilepsy Intellectual disability PACSI PACS2

A Power Data Anomaly Detection Model Based on Deep Learning with Adaptive Feature Fusion

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Computers, Materials & Continua 2024年第6期79卷 4045-4061页

作者： Xiu Liu Liang Gu Xin Gong Long An Xurui gao Juying wu State Grid Information&Telecommunication Co.of SEPC Big Data CenterTaiyuan030000China

With the popularisation of intelligent power,power devices have different shapes,numbers and *** means that the power data has distributional variability,the model learning process cannot achieve sufficient extraction of data features,which seriously affects the accuracy and performance of anomaly ***,this paper proposes a deep learning-based anomaly detection model for power data,which integrates a data alignment enhancement technique based on random sampling and an adaptive feature fusion method leveraging dimension *** at the distribution variability of power data,this paper developed a sliding window-based data adjustment method for this model,which solves the problem of high-dimensional feature noise and low-dimensional missing *** address the problem of insufficient feature fusion,an adaptive feature fusion method based on feature dimension reduction and dictionary learning is proposed to improve the anomaly data detection accuracy of the *** order to verify the effectiveness of the proposed method,we conducted effectiveness comparisons through elimination *** experimental results show that compared with the traditional anomaly detection methods,the method proposed in this paper not only has an advantage in model accuracy,but also reduces the amount of parameter calculation of the model in the process of feature matching and improves the detection speed.

关键词： Data alignment dimension reduction feature fusion data anomaly detection deep learning

Geochemical Characteristics and Hydrocarbon Generation Modeling of the Paleocene Source Rocks in the Jiaojiang Sag,East China Sea Basin

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Journal of Earth Science 2024年第2期35卷 642-654页

作者： Chuang Lei Shiyan Yin Jiaren Ye Jingfu wu Zhaosheng Wang Bin gao Collaborative Innovation Center of Green Development and Ecological Restoration of Mineral Resources North China University of Science and TechnologyTangshan063210China Key Laboratory of Tectonics and Petroleum Resources China University of GeosciencesMinistry of EducationWuhan430074China CNOOC Research Institute Ltd Beijing100028China

Jiaojiang sag in the East China Sea Basin is at the earlier exploration stage,where characterizing hydrocarbon generation of source rocks is important to understand oil-gas exploration *** geochemical and basin modeling analysis,hydrocarbon generation capacity and process of the Paleocene E_(1)y,E_(1)l and E_(1)m formations were *** show that E_(1)y and E_(1)l mudstones are high-quality source rocks with Type Ⅱ kerogen,which is dominated by both aquatic organisms and terrestrial higher plants deposited in sub-reduced environment.E_(1)m mudstone interbedded with thin carbonaceous mudstone and coal is poor-quality source rock with Type Ⅲ kerogen,whose organic matter was originated from terrestrial higher plants under oxidized *** by burial and maturity histories,E_(1)y and E_(1)l source rocks experienced two hydrocarbon generation stages,which took place in the Late Paleocene and in the Middle to Late Eocene,respectively,and had high hydrocarbon generation capacity with cumulative hydrocarbon volume of 363 and 328 mg/g,respectively.E_(1)m source rock only had one hydrocarbon generation process in the Late Eocene,which had low hydrocarbon generation capacity with cumulative hydrocarbon volume of only 24 mg/*** future oil-gas exploration in the Jiaojiang sag should focus on hydrocarbon generation center and select targets in the central uplift formed before the Miocene with high-quality traps.

关键词： East China Sea Basin Jiaojiang sag source rock geochemical characteristics hydrocarbon generation basin modeling petroleum geology

Laboratory and field evaluation of a low-cost optical particle sizer

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Journal of Environmental Sciences 2024年第8期142卷 215-225页

作者： Mingzhen Tang Yicheng Shen Yanzhen Ge Jian gao Chong Wang Liqing wu Shuchun Si State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Jinan Grid-Based Supervision Center of Ecological and Environmental Protection Jinan 250100China Tai’an Ecological Environment Protection Control Center Tai’an 271000China School of Physics Shandong UniversityJinan 250013China

Low-cost sensors are widely used to collect high-spatial-resolution particulate matter data that traditional reference monitoring devices *** addition to the mass concentration,the number concentration and size distribution are also fundamental in determining the origin and hazard level of particulate ***,low-cost optical sensors have been improved to establish optical particle sizers(OPSs).In this study,a low-cost OPS,the Nova SDS029,is introduced,and it is evaluated in comparison to two reference instruments—the GRIMM 11-D and the TSI *** first tested the sizing accuracy using polystyrene latex ***,we assessed the mass and number size distribution accuracy in three application scenarios:indoor smoking,ambient air quality,and mobile *** evaluations suggest that the low-cost SDS029 rivals research-grade optical sizers in many *** example,(1)the particle diameters obtained with the SDS029 are close to the reference instruments(usually<10%)in the 0.3-5μm range;(2)the number of particles and mass concentration are highly correlated(r≥0.99)with the values obtained with the reference instruments;and(3)the SDS029 slightly underestimates the number concentration,but the derived PM_(2.5)values are closer to monitoring station than the reference *** successful application of the SDS029 in multiple scenarios suggests that a plausible particle size distribution can be obtained in an easy and cost-efficient *** believe that low-cost OPSs will increasingly be used to map the sources and risk levels of particles at the city scale.

关键词： Optical particle sizer Particle size distribution Low-cost sensor Evaluation Field application

Efficient Untargeted White-Box Adversarial Attacks Based on Simple Initialization

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Chinese Journal of Electronics 2024年第4期33卷 979-988页

作者： Yunyi ZHOU Haichang gao Jianping HE Shudong ZHANG Zihui wu School of Computer Science and Technology Xidian University

Adversarial examples(AEs) are an additive amalgamation of clean examples and artificially malicious perturbations. Attackers often leverage random noise and multiple random restarts to initialize perturbation starting points, thereby increasing the diversity of AEs. Given the non-convex nature of the loss function, employing randomness to augment the attack's success rate may lead to considerable computational overhead. To overcome this challenge,we introduce the one-hot mean square error loss to guide the initialization. This loss is combined with the strongest first-order attack, the projected gradient descent, alongside a dynamic attack step size adjustment strategy to form a comprehensive attack process. Through experimental validation, we demonstrate that our method outperforms baseline attacks in constrained attack budget scenarios and regular experimental settings. This establishes it as a reliable measure for assessing the robustness of deep learning models. We explore the broader application of this initialization strategy in enhancing the defense impact of few-shot classification models. We aspire to provide valuable insights for the community in designing attack and defense mechanisms.

关键词： Deep learning Additives Perturbation methods Noise Mean square error methods Robustness Glass box

Structural Optimization of the Inlet Header of Supercritical Carbon Dioxide Printed Circuit Board Heat Exchanger

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Journal of Thermal Science 2024年第4期33卷 1458-1467页

作者： WANG Yanquan LU Yuanwei WANG Yuanyuan HAN Xinlong wu Yuting gao Qi MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of TechnologyBeijing100124China

Supercritical carbon dioxide printed circuit board heat exchangers are expected to be applied in third-generation solar thermal power ***,the uniformity of supercritical carbon dioxide entering the heat exchanger has a significant impact on the overall performance of the heat *** order to improve the uniformity of flow distribution in the inlet header,this article studies and optimizes the inlet header of a printed circuit board heat exchanger through numerical *** results indicate that when supercritical carbon dioxide flows through the header cavity,eddy currents will be generated,which will increase the uneven distribution of flow rate,while reducing the generation of eddy currents will improve the uniform distribution of flow *** the dimensionless factor of the inlet header is 6,the hyperbolic configuration is the optimal *** also reduced the eddy current region by adding transition segments,and the results showed that the structure was the best when the dilation angle was 10°,which reduced the non-uniformity by 21%compared to the hyperbolic configuration,providing guidance for engineering practice.

关键词： third-generation solar thermal power generation inlet header PCHE numerical simulation

Strip flatness prediction of cold rolling based on ensemble methods

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Journal of Iron and Steel Research(International) 2024年第1期31卷 237-251页

作者： wu-quan Yang Zhi-ting Zhao Liang-yu Zhu Xun-yang gao Li Wang School of Mechanical and Power Engineering Shenyang University of Chemical TechnologyShenyang110142LiaoningChina

Aiming at the problem of insufficient prediction accuracy of strip flatness at the outlet of cold tandem rolling,the prediction performance of strip flatness based on different ensemble methods was studied and a high-precision prediction ensemble model of strip flatness at the outlet was ***,based on linear regression(LR),K nearest neighbors(KNN),support vector regression,regression trees(RT),and backpropagation neural network(BPN),bagging,boosting,and stacking ensemble methods were used for ensemble ***,three existing ensemble models,i.e.,random forest,extreme random tree(ET)and extreme gradient boosting,were used to conduct experiments and compare the *** research shows that bagging,boosting,and stacking three ensemble methods have the most significant improvement in the prediction accuracy of the regression trees model,which is increased by 5.28%,6.51%,and 5.32%,*** the same time,the stacking ensemble method improves both the simple model and the complex model,and the improvement effect on the simple base model is the greatest,which is 4.69%higher than that of the base model *** all of the ensemble models,the stacking ensemble model of level-1(ET,AdaBoost-RT,LR,BPN)paired with level-2(LR)was discovered to be the best model(EALB-LR)and can be further studied for industrial applications.

关键词： Tandem cold rolling Flatness prediction Machine learning Ensemble method