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Locally and globally uniform approximations for ruin probabilities of a nonstandard bidimensional risk model with subexponential claims

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 98-113页

作者： liu Zai-ming geng Bing-zhen WANG Shi-jie School of Mathematics and Statistics Central South UniversityChangsha 410083China School of Big Data and Statistics Anhui UniversityHefei 230601China

Consider a nonstandard continuous-time bidimensional risk model with constant force of interest,in which the two classes of claims with subexponential distributions satisfy a general dependence structure and each pair of the claim-inter-arrival times is arbitrarily *** some mild conditions,we achieve a locally uniform approximation of the finite-time ruin probability for all time horizon within a finite *** we further assume that each pair of the claim-inter-arrival times is negative quadrant dependent and the two classes of claims are consistently-varying-tailed,it shows that the above obtained approximation is also globally uniform for all time horizon within an infinite interval.

关键词： bidimensional risk model asymptotic formula subexponential distribution consistently varying tail ruin probability

Application of electromagnetic metallurgy in continuous casting: A review

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Progress in Natural Science:Materials International 2024年第1期34卷 1-11页

作者： Jiale Li Yi nian Xiang liu Youcheng Zong Xinyu Tang Chaojie Zhang Liqiang Zhang The Intelligent Metallurgy Research Institute School of Metallurgical Engineering Anhui University of Technology

The standards within the global steel industry are constantly advancing, necessitating increasingly rigorous quality control protocols during the continuous casting process. Central to the challenges faced in this domain are persistent defects such as central segregation, V-shaped segregation, and center porosity, which significantly impede the production of high-caliber steel products. The discipline of electromagnetic metallurgy has emerged as a critical solution in reducing these defects, thereby enhancing the efficiency and stability of continuous casting operations. Its demonstrated effectiveness has led to its widespread implementation across global and domestic steel production industries. This paper aims to deliver a comprehensive examination of electromagnetic metallurgy's impact on the final stages of solidification in continuous casting, along with its contributions to the heating and purification processes within the tundish. Additionally, it will explore the potential advancements and applications of this technology in the evolving sphere of continuous casting.

关键词： continuous casting Quality control Final electromagnetic stirring Induction heating Electromagnetic purification

Controllable Ring-opening Polymerization ofδ-Valerolactone Catalyzed by Quinolinyl-Urea/MTBD Systems

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Chinese Journal of Polymer Science 2024年第8期42卷 1103-1110页

作者： Xin-Yu liu Liang Zhu Su-Yun Jie Bo-geng Li State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310058China

Due to their excellent biocompatibility and biodegradability,aliphatic polyesters are widely used in the biomedical,packaging and agricultural fields,which are usually accessed by the ring-opening polymerization(ROP)of lactones and the catalysts particularly play an important *** a series of quinolinyl-urea catalysts have been synthesized via the reaction between isocyanate and aminoquinoline with an amino group at different substitution positions and *** combination with 7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene(MTBD)as a cocatalyst and benzyl alcohol(BnOH)as an initiator,1-(3,5-bis(trifluoromethyl)phenyl)-3-(quinolin-3-yl)urea(3-QU)was observed to be most active for the ROP ofδ-valerolactone(δ-VL).The polymerization conditions were optimized by varying the type of organic base,catalyst concentration and reaction *** changing the ratio of[M]_0/[I],linear polyvalerolactones(PVLs)with different molecular weights and narrow molecular weight distribution were *** kinetic and chain extension experiments were carried out to prove the"living"/controllable *** the NMR experiments were used to support the proposal of possible mechanism.

关键词： Quinolinyl-urea Ring-opening polymerization PVL

冰川槽谷横剖面沿程变化及其对冰川动力的反映

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地理学报 2000年第2期55卷 235-242页

作者：李英奎刘耕年北京大学城市与环境学系北京100871

冰川槽谷梯级宽深比定义为槽谷横剖面上相同等高线间距离与对应深度的比值。它可以描述槽谷横剖面形态的总体特征 ,便于不同槽谷横剖面形态的对比。统计分析表明槽谷梯级宽深比随槽谷深度的变化符合幂函数模型。使用这一模型描述冰川槽... 详细信息

冰川槽谷梯级宽深比定义为槽谷横剖面上相同等高线间距离与对应深度的比值。它可以描述槽谷横剖面形态的总体特征 ,便于不同槽谷横剖面形态的对比。统计分析表明槽谷梯级宽深比随槽谷深度的变化符合幂函数模型。使用这一模型描述冰川槽谷横剖面的总体形态并据此探讨冰川槽谷横剖面形态的沿程变化。主要结论如下 :简单槽谷从上源到雪线附近 ,模型参数显示为槽谷展宽 ,谷壁变陡 ,从雪线向下游 ,槽谷变窄 ,谷壁变缓 ;从简单槽谷段向复合槽谷段 ,槽谷明显展宽 ,谷壁变陡 ,从复合槽谷段向单流槽谷段 ,槽谷变窄。

关键词：冰川动力冰川槽谷横剖面沿程变化

A continuous-wave Nd:YVO_(4)-KGW intracavity Raman laser with over 34% diode-to-Stokes optical efficiency

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High Power Laser Science and Engineering 2024年第2期12卷 62-68页

作者： Quan Sheng Jingni geng Tianchang liu Shijie Fu Wei Shi Jianquan Yao Institute of Laser and Optoelectronics School of Precision Instrument and Optoelectronics EngineeringTianjin UniversityTianjinChina Key Laboratory of Optoelectronic Information Technology(Ministry of Education) Tianjin UniversityTianjinChina

We demonstrate a continuous-wave(CW)Nd:YVO_(4)-potassium gadolinium tungstate(KGW)intracavity Raman laser with a diode-to-Stokes optical efficiency of 34.2%.By optimizing the cavity arrangement and reducing the cavity losses,8.47 W Stokes output at 1177 nm was obtained under an incident 878.6 nm diode pump power of 24.8 *** influence of cavity losses on the power and efficiency of the CW Raman laser,as well as the potential for further optimization,was investigated based on the numerical *** observation of thermally-induced output rollover was well explained by the calculation of the thermal lensing and cavity stability,indicating that the end-face curvature played an important role when the end-face of the crystal was highly reflective coated to make the cavity.A 10.9 W Stokes output under 40.9 W incident pump was also demonstrated with a cavity arrangement less sensitive to the end-face curvature,which is the highest output power of CW intracavity Raman lasers reported.

关键词： continuous wave intracavity Raman laser KGW crystal thermal lens

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A novel deep learning framework with variational auto-encoder for indoor air quality prediction

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Frontiers of Environmental Science & Engineering 2024年第1期18卷 97-109页

作者： Qiyue Wu Yun geng Xinyuan Wang Dongsheng Wang ChangKyoo Yoo Hongbin liu Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources Nanjing Forestry UniversityNanjing 210037China College of Automation&College of Artificial Intelligence Nanjing University of Posts and TelecommunicationsNanjing 210023China Guangxi Key Laboratory of Clean Pulp&Papermaking and Pollution Control College of Light Industry and Food EngineeringGuangxi UniversityNanning 530004China Laboratory for Comprehensive Utilization of Paper Waste of Shandong Province Shandong Huatai Paper Co.Ltd.Dongying 257335China Department of Environmental Science and Engineering College of EngineeringKyung Hee UniversityYongin 446701Republic of Korea

Exposure to poor indoor air conditions poses significant risks to human health, increasing morbidity and mortality rates. Soft measurement modeling is suitable for stable and accurate monitoring of air pollutants and improving air quality. Based on partial least squares (PLS), we propose an indoor air quality prediction model that utilizes variational auto-encoder regression (VAER) algorithm. To reduce the negative effects of noise, latent variables in the original data are extracted by PLS in the first step. Then, the extracted variables are used as inputs to VAER, which improve the accuracy and robustness of the model. Through comparative analysis with traditional methods, we demonstrate the superior performance of our PLS-VAER model, which exhibits improved prediction performance and stability. The root mean square error (RMSE) of PLS-VAER is reduced by 14.71%, 26.47%, and 12.50% compared to single VAER, PLS-SVR, and PLS-ANN, respectively. Additionally, the coefficient of determination (R2) of PLS-VAER improves by 13.70%, 30.09%, and 11.25% compared to single VAER, PLS-SVR, and PLS-ANN, respectively. This research offers an innovative and environmentally-friendly approach to monitor and improve indoor air quality.

关键词： Indoor air quality PM_(2.5)concentration Variational auto-encoder Latent variable Soft measurement modeling

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天山玛纳斯河源鹿角湾冰川地貌与冰期序列

冰川冻土 2005年第6期27卷 907-912页

作者：鞠远江刘耕年中国矿业大学资源学院江苏徐州221008 北京大学环境学院北京100871

在鹿角湾冰川区40 km2的考察范围内, 共发育了18个冰斗. 按斗底高度的不同, 可以将18个冰斗分成3个高度等级, 分别代表了3次雪线高度不同的冰进. 冰斗朝向以偏北为主, 说明水热条件对冰斗发育是限制因素. 18号冰斗和2号冰斗朝向偏南, ... 详细信息

在鹿角湾冰川区40 km2的考察范围内, 共发育了18个冰斗. 按斗底高度的不同, 可以将18个冰斗分成3个高度等级, 分别代表了3次雪线高度不同的冰进. 冰斗朝向以偏北为主, 说明水热条件对冰斗发育是限制因素. 18号冰斗和2号冰斗朝向偏南, 说明其所代表的冰进阶段水热条件组合有利于冰川的长期存在, 从而发育了大规模的向阳冰斗. 鹿角湾冰川共发育了10道保存比较完整的冰碛垄, 按冰碛垄表面特征和产出位置, 结合测年资料, 将10道冰碛垄划分为5套冰碛地层. 对冰碛垄上所采冰碛土样品进行年代测试的结果是: 冰碛丘陵上组地层属于小冰期沉积, 较早的两次冰进结束时间为(680±60)a BP和(250±60)a BP; 冰碛丘陵组地层属于新冰期沉积, 3次冰进结束年代分别为: (4.2±0.4)ka BP, (2.9±0.3)ka BP, (1 720±60)a BP; 末次冰期晚期结束年代为1.1～1.2 ka BP.其它几次冰进阶段未能取得可信的测年数据.

关键词：天山玛纳斯河源地貌冰期序列

Clinical efficacy and safety of erlotinib combined with chemotherapy in the treatment of advanced pancreatic cancer:A meta-analysis

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World Journal of Gastrointestinal Surgery 2024年第3期16卷 921-931页

作者： Xiao-Yan liu Hong-nian Pan Yue Yu Cheeloo College of Medicine Shandong UniversityJinan 250012Shandong ProvinceChina Department of Gastroenterology The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230001Anhui ProvinceChina Department of Gastroenterology The Lu’an Hospital Affiliated to Anhui Medical UniversityThe Lu’an People's HospitalLu’an 237000Anhui ProvinceChina

BACKGROUND Advanced pancreatic cancer is resistant to chemotherapeutic drugs,resulting in limited treatment efficacy and poor *** administration of the chemotherapeutic gemcitabine and erlotinib is considered a potential first-line treatment for advanced pancreatic ***,their comparative benefits and potential risks remain *** To assess the clinical efficacy and safety of erlotinib combined with other chemotherapy regimens for the treatment of advanced pancreatic *** Literature on the clinical efficacy and safety of erlotinib combined with chemotherapy for advanced pancreatic cancer was retrieved through an online *** retrieved literature was subjected to a methodological qualitative assessment and was analyzed using the RevMan 5.3 *** randomized controlled trials involving 2444 patients with advanced pancreatic cancer were included in the *** Compared with chemotherapeutic treatment,erlotinib combined with chemotherapy significantly prolonged the progression-free survival time of pancreatic cancer patients[hazard ratio(HR)=0.78,95%CI:0.66-0.92,P=0.003].Meanwhile,the overall survival(HR=0.99,95%CI:0.72-1.37,and P=0.95)and disease control rate(OR=0.93,95%CI:0.45-0.91,P=0.84)were not significantly *** terms of safety,the erlotinib and chemotherapy combination was associated with a significantly higher risk of diarrhea(OR=3.59,95%CI:1.63-7.90,P<0.05)and rash(OR=3.63,95%CI:1.64-8.01,P<0.05)compared with single-agent ***,the risk of vomiting(OR=1.27,95%CI:0.62-2.59,P=0.51),regurgitation/anorexia(OR=1.61,95%CI:0.25-10.31,P=0.62),and infection(OR=0.72,95%CI:0.28-1.87,P=0.50)were not significant in either *** Compared with a single chemotherapeutic modality,erlotinib combined with gemcitabine can prolong progression-free survival in pancreatic cancer,but does not improve survival benefit or disease control rate,and can increase the risk of diarrhea and rash.

关键词： Erlotinib Chemotherapy Advanced pancreatic cancer Efficacy Safety Meta-analysis

Mechanical response of a tunnel subjected to strike-slip faulting processes,based on a multi-scale modeling method

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1281-1295页

作者： Guoguo liu Ping geng Tianqiang WANG Xiangyu GUO Jiaxiang WANG Ti DING Key Laboratory of Transportation Tunnel Engineering Ministry of EducationChengdu 610031China College of Civil Engineering Huaqiao UniversityXiamen 361021China China Railway Design Corporation Tianjin 300308China

The stick-slip action of strike-slip faults poses a significant threat to the safety and stability of underground *** this study,the north-east area of the Longmenshan fault,Sichuan,provides the geological background;the rheological characteristics of the crustal lithosphere and the nonlinear interactions between plates are described by Burger’s viscoelastic constitutive model and the friction constitutive model,respectively.A large-scale global numerical model for plate squeezing analysis is established,and the seemingly periodic stick-slip action of faults at different crust depths is *** a second model at a smaller scale,a local finite element model(sub-model),the time history of displacement at a ground level location on the Longmenshan fault plane in a stick-slip action is considered as the displacement *** integration of these models,creating a multi-scale modeling method,is used to evaluate the crack propagation and mechanical response of a tunnel subjected to strike-slip *** determinations of the recurrence interval of stick-slip action and the cracking characteristics of the tunnel are in substantial agreement with the previous field investigation and experimental results,validating the multi-scale modeling *** can be concluded that,regardless of stratum stiffness,initial cracks first occur at the inverted arch of the tunnel in the footwall,on the squeezed side under strike-slip *** smaller the stratum stiffness is,the smaller the included angle between the crack expansion and longitudinal direction of the tunnel,and the more extensive the crack expansion *** the tunnel in a high stiffness stratum,both shear and bending failures occur on the lining under strike-slip faulting,while for that in the low stiffness stratum,only bending failure occurs on the lining.

关键词： stick-slip action plate squeezing analysis multi-scale modeling method lining cracking mechanical response