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Mechanism of local solidification time variations with melt rate during vacuum arc remelting process of 8Cr4Mo4V high-strength steel

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Journal of Iron and Steel Research International 2024年第2期31卷 377-388页

作者： Tao Pan Hong-chun Zhu Zhou-hua jiang hua-bing Li Rui Zhang Hao Feng School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina

A 2D axisymmetric numerical model was established to investigate the variations of molten pool with different melt rates during the vacuum arc remelting of 8Cr4Mo4V high-strength steel,and the ingot growth was simulated by dynamic mesh *** results show that as the ingot grows,the molten pool profile changes from shallow and flat to V-shaped,and both the molten pool depth and the mushy width ***,the variation of both the molten pool shape and the mushy width melt rate is clarified by the thermal equilibrium *** melt rate increases,both the molten pool depth and the mushy width *** is caused by the increment in sensible heat stored in the ingot due to the limitation of the cooling capacity of the *** nonlinear increment in sensible heat leads to a nonlinear increase in the mushy *** addition,as melt rate increases,the local solidification time(LST)of ingot decreases obviously at first and then *** melt rate is controlled in a suitable range,LST is the lowest and the secondary dendrite arm spacing of the ingot is the smallest,which can effectively improve the compactness degree of 8Cr4Mo4V high-strength steel.

关键词： 8Cr4Mo4V high-strength steel Vacuum arc remelting process Melt rate Molten pool Local solidification time

The Limitations and Ethical Considerations of ChatGPT

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Data Intelligence 2024年第1期6卷 201-239页

作者： Shangying hua Shuangci Jin Shengyi jiang Guangdong University of Foreign Studies Guangzhou 510000China

With the advancements of artificial intelligence technology,ChatGPT,a new practice of artificial intelligence,holds immense potential across multiple *** user-friendly human-machine interface,rapid response capabilities,and delivery of high-quality answers have attracted considerable attention and widespread *** by many as a groundbreaking advancement in AI,ChatGPT represents a new milestone in the ***,as with any technological evolution,the emergence of ChatGPT brings not only benefits,but also inevitable security risks and ethical *** paper provides specific information about ChatGPT,including its technology,limitations,ethical issues,governance paths and future ***,we firstly offered a thorough exploration of the technical implementation details of GPT series ***,we provided an intricate analysis elucidating the reasons for limitations and scrutinized the consequential impacts,such as malicious misuse,privacy violation,and so ***,we explore diverse governance paths to mitigate the impacts of ChatGPT and present future *** review aims to equip users with crucial knowledge,facilitating well-informed decision-making,effectively handling of potential challenges in employing ChatGPT,and staying abreast with the rapidly evolving landscape of this technology.

关键词： ChatGPT ChatGPT Technology Limitations Ethical considerations Artificial Intelligence

Predictive modeling for postoperative delirium in elderly patients with abdominal malignancies using synthetic minority oversampling technique

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1227-1235页

作者： Wen-jing Hu Gang Bai Yan Wang Dong-Mei Hong Jin-hua jiang Jia-Xun Li Yin hua Xin-Yu Wang Ying Chen Intensive Care Unit Shanghai Fourth People’s Hospital Affiliated to Tongji University School of MedicineShanghai 200434China Department of Anesthesia and Perioperative Medicine Shanghai Fourth People’s Hospital Affiliated to Tongji University School of MedicineShanghai 200434China Department of Nursing Shanghai Fourth People’s Hospital Affiliated to Tongji University School of MedicineShanghai 200434China Department of Thyroid Breast and Vascular SurgeryShanghai Fourth People’s Hospital Affiliated to Tongji University School of MedicineShanghai 200434China

BACKGROUND Postoperative delirium,particularly prevalent in elderly patients after abdominal cancer surgery,presents significant challenges in clinical *** To develop a synthetic minority oversampling technique(SMOTE)-based model for predicting postoperative delirium in elderly abdominal cancer *** In this retrospective cohort study,we analyzed data from 611 elderly patients who underwent abdominal malignant tumor surgery at our hospital between September 2020 and October *** incidence of postoperative delirium was recorded for 7 d *** were divided into delirium and non-delirium groups based on the occurrence of postoperative delirium or not.A multivariate logistic regression model was used to identify risk factors and develop a predictive model for postoperative *** SMOTE technique was applied to enhance the model by oversampling the delirium *** model’s predictive accuracy was then *** In our study involving 611 elderly patients with abdominal malignant tumors,multivariate logistic regression analysis identified significant risk factors for postoperative *** included the Charlson comorbidity index,American Society of Anesthesiologists classification,history of cerebrovascular disease,surgical duration,perioperative blood transfusion,and postoperative pain *** incidence rate of postoperative delirium in our study was 22.91%.The original predictive model(P1)exhibited an area under the receiver operating characteristic curve of *** comparison,the SMOTE-based logistic early warning model(P2),which utilized the SMOTE oversampling algorithm,showed a slightly lower but comparable area under the curve of 0.856,suggesting no significant difference in performance between the two predictive *** This study confirms that the SMOTE-enhanced predictive model for postoperative delirium in elderly abdominal tumor patients shows performance equivalent to that of tradi

关键词： Elderly patients Abdominal cancer Postoperative delirium Synthetic minority oversampling technique Predictive modeling Surgical outcomes

Solvothermal synthesis and adsorption performance of layered boehmite using aluminum chloride and high-alumina fly ash

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Chinese Journal of Chemical Engineering 2024年第6期70卷 280-290页

作者： jing Wen Ruirui Yuan Tao jiang Tangxia Yu Yufan Zhang School of Metallurgy Northeastern UniversityShenyang 110819China Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819China Liaoning Key Laboratory for Metallurgical Sensor and Technology Shenyang 110819China

High alumina fly ash(FAHAl)is a kind of bulk solid waste unique to China,whose availability of high-value aluminum and the threat to the environment makes its high-value utilization *** this work,the alumina containing leaching solution obtained from Na_(2)CO_(3) roasting and HCl leaching of FAHAl was used as the mother liquor to prepare layered boehmite in *** preparation process with AlCl_(3) as the raw material was also *** formation process and mechanism of boehmite,the choice of solvent,along with the adsorption capability of Congo red were analyzed by X-ray diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,Brunauer-Emmett-Teller method and adsorption *** showed that during the preparation of layered boehmite,the precursor Al(OH)_(3) from the reaction of Al^(3+) and OH-is transformed into boehmiteγ-*** existence of ethanol is beneficial to regulate and promote the growth of boehmite crystal *** water and ethanol are mixed with a volume ratio of 2:1 and used as the solvent,the maximum specific surface area of the boehmite is obtained at 135.7 m^(2)·g^(-1),and 99.16%of Congo red can be absorbed after 10 min when AlCl3 is used as a raw *** purified leaching solution is used as the mother liquid,the crystallinity of boehmite decreases slightly when the pH value decreases from 12.5 to *** pH is 11,the removal efficiency of Congo red reaches a maximum of 72.25%.This process not only achieves the extraction of aluminum and high-value utilization of FAHAl but also provides a thought to prepare layered boehmite with adsorption properties.

关键词： High-alumina fly ash Layered boehmite In-situ preparation Solvothermal synthesis Adsorption High-value utilization

Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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Chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： Chi Zhang Rong Liu jing-Yuan Liu Wen-Wei jiang Key Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

Constrained clustering with weak label prior

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Frontiers of Computer Science 2024年第3期18卷 117-132页

作者： jing ZHANG Ruidong FAN Hong TAO Jiacheng jiang Chenping HOU College of Sciences National University of Defense TechnologyChangsha 410073China

Clustering is widely exploited in data *** has been proved that embedding weak label prior into clustering is effective to promote its *** researches mainly focus on only one type of ***,in many real scenarios,two kinds of weak label prior information,e.g.,pairwise constraints and cluster ratio,are easily obtained or already *** to incorporate them to improve clustering performance is important but rarely *** propose a novel constrained Clustering with Weak Label Prior method(CWLP),which is an integrated *** the unified spectral clustering model,the pairwise constraints are employed as a regularizer in spectral embedding and label proportion is added as a constraint in spectral *** approximate a variant of the embedding matrix more precisely,we replace a cluster indicator matrix with its scaled *** of fixing an initial similarity matrix,we propose a new similarity matrix that is more suitable for deriving clustering *** for the theoretical convergence and computational complexity analyses,we validate the effectiveness of CWLP through several benchmark datasets,together with its ability to discriminate suspected breast cancer patients from healthy *** experimental evaluation illustrates the superiority of our proposed approach.

关键词： clustering weak label prior cluster ratio pairwise constraints

Core shift limitation in investment casting process of hollow turbine blade

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Chinese Journal of Aeronautics 2024年第8期37卷 513-526页

作者： Kang CUI Lin jing Ruisong jiang Longnv YU Xiao GAO Automation and Software Engineering Shanxi UniversityTaiyuan 030006China Key Laboratory of High Performance Manufacturing for Aero Engine Ministry of Industry and Information TechnologySchool of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China School of Mechanical Engineering Sichuan UniversityChengdu 610065China

The deviation in wall thickness caused by core shift during the investment casting process significantly impacts the strength and service life of hollow turbine *** address this issue,a core shift limitation method is developed in this ***,a shift model is established based on computational fluid dynamics and motion simulation to predict the movement of the ceramic core in investment casting ***,utilizing this model,an optimization method for fixturing layout inside the refractory ceramic shell is devised for the ceramic *** casting experiment demonstrates that by utilizing the optimized fixture layout,not only can core shift during the investment casting pouring process be effectively controlled,but also the maximum wall thickness error of the blade can be reduced by 42.02%.In addition,the core shift prediction is also validated,with a prediction error of less than 26.9%.

关键词： Hollow turbine blade Wall thickness Ceramic core Shift prediction Fixturing layout optimization

Design of dual-functional protic porous ionic liquids for boosting selective extractive desulfurization

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Petroleum Science 2024年第4期21卷 2817-2829页

作者： Jin-Rui Zhang Jie Yin jing He Hong-Shun Ran Wei jiang Hong-Ping Li Wen-Shuai Zhu hua-Ming Li Ming Zhang School of the Environment and Safety Engineering & Institute for Energy Research Jiangsu University School of Chemistry and Chemical Engineering Jiangsu University

Porous ionic liquids have demonstrated excellent performance in the field of separation, attributed to their high specific surface area and efficient mass transfer. Herein, task-specific protic porous ionic liquids(PPILs) were prepared by employing a novel one-step coupling neutralization reaction strategy for extractive desulfurization. The single-extraction efficiency of PPILs reached 75.0% for ***, adding aromatic hydrocarbon interferents resulted in a slight decrease in the extraction efficiency of PPILs(from 45.2% to 37.3%, 37.9%, and 33.5%), indicating the excellent extraction selectivity of PPILs. The experimental measurements and density functional theory calculations reveal that the surface channels of porous structures can selectively capture dibenzothiophene by the stronger electrophilicity(Eint(HS surface channel/DBT)=-39.8 kcal mol-1), and the multiple extraction sites of ion pairs can effectively enrich and transport dibenzothiophene from the oil phase into PPILs through π...π, C-H...π and hydrogen bonds interactions. Furthermore, this straightforward synthetic strategy can be employed in preparing porous liquids, offering new possibilities for synthesizing PPILs with tailored functionalities.

关键词： Protic porous ionic liquids Extractive desulfurization Selectivity Density functional theory

Analysis of rail-bridge interaction of a high-speed railway suspension bridge under near-fault pulse-type earthquakes

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Transportation Safety and Environment 2024年第3期6卷 71-84页

作者： Xiangdong Yu Bangzheng jiang Haiquan jing School of Civil Engineering Central South UniversityChangsha 410075HunanChina

Due to the limitations of railway route selection,some high-speed railways are inevitably built near or across fault *** study the distribution of rail-bridge interaction under different load history states of suspension bridges under three types of near-fault pulse-type earthquakes,this paper takes China’s longest high-speed railway suspension bridge—Wufengshan Yangtze River Bridge-as the background and establishes a spatial model of the rail-bridge interaction of a suspension *** results show that:under the constant load state,the distribution of additional force under three types of pulse-type earthquakes is generally consistent,and pulse-type earthquakes produce more significant responses than non-pulse-type earthquakes;with fling-step pulse being the largest,it is advised to specifically consider the influence of the fling-step pulse in the *** the initial condition of the main beam temperature loading history,all rail-bridge additional forces increase significantly,particularly affecting the steel rail *** value of the rail-bridge interaction additional force under the near-fault earthquake in the initial state of the suspension bridge when the train deflection load is loaded from the tower to the mid-span is more significant and particularly *** initial effect of the braking load will weaken the effect of the deflection load loading *** results of the study indicate that the effect of the initial state of suspension bridges is an important factor influencing the rail-bridge interaction under near-fault pulse-type earthquakes,which needs to be considered in future seismic design.

关键词： rail-bridge interaction high-speed railway suspension bridge near-fault pulse-type earthquakes loading history initial state