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ESMO2023:恩扎卢胺联合雄激素剥夺治疗对比安慰剂联合雄激素剥夺治疗在中国转移性激素敏感性前列腺癌患者中的疗效和安全性(中国ARCHES)
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作者 李永红 《现代泌尿外科杂志》 2024年第1期81-82,共2页
2019年发表的全球ARCHES试验(NCT02677896)结果显示,与安慰剂(placebo,PBO)+雄激素剥夺治疗(androgen deprivation therapy,ADT)相比,恩扎卢胺+ADT延长了转移性激素敏感性前列腺癌(metastatic hormone-sensitive prostate cancer,mHSPC... 2019年发表的全球ARCHES试验(NCT02677896)结果显示,与安慰剂(placebo,PBO)+雄激素剥夺治疗(androgen deprivation therapy,ADT)相比,恩扎卢胺+ADT延长了转移性激素敏感性前列腺癌(metastatic hormone-sensitive prostate cancer,mHSPC)患者的总生存期和放射影像学无进展生存期(radiographic progression-free survival,rPFS)^([1])。然而,该试验无中国患者入组。欧洲肿瘤内科学会(European Society for Medical Oncology,ESMO)2023年会议报道了中国ARCHES研究(NCT04076059)的初步结果,这是一项评估恩扎卢胺+ADTvs.PBO+ADT在中国m HSPC患者中的疗效和安全性的多中心、随机、双盲、PBO对照的Ⅲ期试验^([2])。 展开更多
关键词 转移性激素敏感性前列腺癌 恩扎卢胺 雄激素剥夺治疗 安慰剂 中国患者 archES
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Health diagnosis of ultrahigh arch dam performance using heterogeneous spatial panel vector model
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作者 Er-feng Zhao Xin Li Chong-shi Gu 《Water Science and Engineering》 EI CAS CSCD 2024年第2期177-186,共10页
Currently,more than ten ultrahigh arch dams have been constructed or are being constructed in China.Safety control is essential to long-term operation of these dams.This study employed the flexibility coefficient and ... Currently,more than ten ultrahigh arch dams have been constructed or are being constructed in China.Safety control is essential to long-term operation of these dams.This study employed the flexibility coefficient and plastic complementary energy norm to assess the structural safety of arch dams.A comprehensive analysis was conducted,focusing on differences among conventional methods in characterizing the structural behavior of the Xiaowan arch dam in China.Subsequently,the spatiotemporal characteristics of the measured performance of the Xiaowan dam were explored,including periodicity,convergence,and time-effect characteristics.These findings revealed the governing mechanism of main factors.Furthermore,a heterogeneous spatial panel vector model was developed,considering both common factors and specific factors affecting the safety and performance of arch dams.This model aims to comprehensively illustrate spatial heterogeneity between the entire structure and local regions,introducing a specific effect quantity to characterize local deformation differences.Ultimately,the proposed model was applied to the Xiaowan arch dam,accurately quantifying the spatiotemporal heterogeneity of dam performance.Additionally,the spatiotemporal distri-bution characteristics of environmental load effects on different parts of the dam were reasonably interpreted.Validation of the model prediction enhances its credibility,leading to the formulation of health diagnosis criteria for future long-term operation of the Xiaowan dam.The findings not only enhance the predictive ability and timely control of ultrahigh arch dams'performance but also provide a crucial basis for assessing the effectiveness of engineering treatment measures. 展开更多
关键词 Ultrahigh arch dam Structural performance Deformation behavior Diagnosis criterion Panel data model
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Three-Center Configuration with Four,Three, and Two Electrons for Carbon,Boron, Hydrogen, and Halogen Exchange. A Model and Theoretical Study with Experimental Evidence 被引量:1
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作者 Henk M. Buck 《Open Journal of Physical Chemistry》 2014年第2期33-43,共11页
The introduction of specific sites in organic frames for accommodation of various modes of bonding has been focused on reaction types which are described by using different theoretical models with or without a definit... The introduction of specific sites in organic frames for accommodation of various modes of bonding has been focused on reaction types which are described by using different theoretical models with or without a definite experimental proof. In this study three-center four-, three-, and two-electron systems based on carbon-, boron-, hydrogen-, and halogen exchange are under consideration. Based on the number of electrons in the transition state or transition complex it is shown that all transfer or exchange reactions share the same ratio numbers expressed as the quotient of the transitional bond distance under investigation and its normal bond length. With X-ray data of model systems it was even possible to give the ratio numbers for a three-center four-electron configuration experimental support with additional ab initio data. Furthermore a novel model type of substitution in organic chemistry is introduced through electrophilic insertion, informative for enzyme-substrate interactions based on the lock-and-key model. Reactions based on a three-center two-electron configuration mostly follow a nonlinear transition. In this alignment there will be a pursuit of cyclization for stabilization via homoaromaticity as homocyclopropenyl cation. The molecular dynamics of such a process is discussed based on recent X-ray crystallographic data of the symmetrically bridged, nonclassical geometry of the 2-norbornyl cation. In the present paper the focus is aimed at the transition intermediate of the (classical) 2-norbornyl cation involved in the isomerization into the nonclassical geometry. This model description is compared with a simple molecular rearrangement of the 1-propyl cation into the corner-protonated cyclopropane using the ab initio data. The exclusivity of the former isomerization compared with the latter one could be unambiguously demonstrated by the invention that theintramolecularelectron shift can be expressed in a linear relationship between the concerned electron-donating and accepting bond lengths. Finally, the fluor transitions as divalent atoms in a three-center two-electron configuration are described. The role of fluor in comparison with the other halogens is striking. The attention was focused on an excellent correspondence between the recent chemical and theoretical evidence for a symmetrical fluoronium ionin solution. Simple dialkylfluoroniumions in contrast to the other halonium ions are not present in solution. Although the geometry of the fluoronium ion theoretically can be described as a real minimum, the C-F-C angle of 120° is apparently the borderline transition for dissociation in C+ and F-C. 展开更多
关键词 three-center CONFIGURATION Frozen Transition State Molecular DRONE ENIGMA Classical and NONCLASSICAL 2-Norbornyl Cation
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Mechanical properties and influence mechanism of confined concrete arches in high-stress tunnels 被引量:3
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作者 Bei Jiang Zhongxin Xin +4 位作者 Xiufeng Zhang Yusong Deng Mingzi Wang Shidong Li Wentao Ren 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第7期829-841,共13页
Deep underground projects(e.g., coal mines), are often faced with complex conditions such as high stress and extremely soft rock. The strength and rigidity of the traditional support system are often insufficient,whic... Deep underground projects(e.g., coal mines), are often faced with complex conditions such as high stress and extremely soft rock. The strength and rigidity of the traditional support system are often insufficient,which makes it difficult to meet the requirements of ground control under complex conditions. As a new support form with high strength and rigidity, the confined concrete arch plays an important role in controlling the rock deformation under complex conditions. The section shape of the tunnel has an important impact on the mechanical properties and design of the support system. However, studies on the mechanical properties and influence mechanism of the new confined concrete arch are rarely reported. To this end, the mechanical properties of traditional U-shaped steel and new confined concrete arches are compared and comparative tests on arches of circular and straight-leg semicircular shapes in deep tunnels are conducted. A large mechanical testing system for underground engineering support structure is developed. The mechanical properties and influence mechanism of confined concrete arches with different section shapes under different loading modes and cross-section parameters are systematically studied. Test results show that the bearing capacity of the confined concrete arch is 2.10 times that of the U-shaped steel arch, and the bearing capacity of the circular confined concrete arch is 2.27 times that of the straight-leg semicircular arch. Among the various influencing factors and their engineering parameters,the lateral stress coefficient has the greatest impact on the bearing capacity of the confined concrete arch,followed by the steel pipe wall thickness, steel strength, and core concrete strength. Subsequently, the economic index of bearing capacity and cost is established, and the optimization design method for the confined concrete arch is proposed. Finally, this design method is applied to a high-stress tunnel under complex conditions, and the deformation of the surrounding rock is effectively controlled. 展开更多
关键词 High-stress tunnel Confined concrete arch Section shape Mechanical properties Design method
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Structural Damage Identification System Suitable for Old Arch Bridge in Rural Regions: Random Forest Approach 被引量:1
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作者 Yu Zhang Zhihua Xiong +2 位作者 Zhuoxi Liang Jiachen She Chicheng Ma 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第7期447-469,共23页
A huge number of old arch bridges located in rural regions are at the peak of maintenance.The health monitoring technology of the long-span bridge is hardly applicable to the small-span bridge,owing to the absence of ... A huge number of old arch bridges located in rural regions are at the peak of maintenance.The health monitoring technology of the long-span bridge is hardly applicable to the small-span bridge,owing to the absence of technical resources and sufficient funds in rural regions.There is an urgent need for an economical,fast,and accurate damage identification solution.The authors proposed a damage identification system of an old arch bridge implemented with amachine learning algorithm,which took the vehicle-induced response as the excitation.A damage index was defined based on wavelet packet theory,and a machine learning sample database collecting the denoised response was constructed.Through comparing three machine learning algorithms:Back-Propagation Neural Network(BPNN),Support Vector Machine(SVM),and Random Forest(R.F.),the R.F.damage identification model were found to have a better recognition ability.Finally,the Particle Swarm Optimization(PSO)algorithm was used to optimize the number of subtrees and split features of the R.F.model.The PSO optimized R.F.model was capable of the identification of different damage levels of old arch bridges with sensitive damage index.The proposed framework is practical and promising for the old bridge’s structural damage identification in rural regions. 展开更多
关键词 Old arch bridge damage identification machine learning random forest particle swarm optimization
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Improved super-elastic Ti–Ni alloy wire intrusion arch for skeletal class Ⅱ malocclusion combined with deep overbite:A case report 被引量:1
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作者 Ching-Yu Yang Chih-Chieh Lin +2 位作者 I-Jia Wang Yuan-Hou Chen Jian-Hong Yu 《World Journal of Clinical Cases》 SCIE 2023年第17期4142-4151,共10页
BACKGROUND Treatment for deep overbite cases can be difficult. This case report presents some techniques with improved super-elastic Ti–Ni alloy wire(ISW) for deep overbite correction.CASE SUMMARY A 21-year-old woman... BACKGROUND Treatment for deep overbite cases can be difficult. This case report presents some techniques with improved super-elastic Ti–Ni alloy wire(ISW) for deep overbite correction.CASE SUMMARY A 21-year-old woman had a chief complaint of flaring maxillary teeth. Orthodontic evaluation revealed a skeletal class Ⅱ malocclusion and a convex profile appearance. A deep overbite with palatal impingement and large overjet were also noted. Bilateral maxillary first premolars were extracted, and spaces were closed using a closed-coil spring and elastic chain. The deep overbite was corrected by applying the ISW curve and ISW intrusion arch. Intermaxillary elastics was used to adjust the intermaxillary relationship. Active treatment took approximately 3 years, and the appearance and dentition alignment noticeably improved.CONCLUSION The use of the ISW technique in a case of skeletal class Ⅱ malocclusion with deep overbite achieved a desirable result, and the patient was satisfied with the treatment outcome. 展开更多
关键词 Dentistry ORTHODONTICS Skeletal class II Intrusion arch Case report
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基于ARCH族模型的石油价格波动性分析
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作者 晁玉 王传会 《国际会计前沿》 2023年第2期235-244,共10页
随着中国成为世界第二大经济实体,能源在经济发展方面的重要地位也与日俱增,石油价格的波动牵动着全球经济的“神经”,会对经济发展产生极大的影响,因此降低石油价格波动所产生风险非常必要。本文以1987~2021年WTI原油价格为原始数据,利... 随着中国成为世界第二大经济实体,能源在经济发展方面的重要地位也与日俱增,石油价格的波动牵动着全球经济的“神经”,会对经济发展产生极大的影响,因此降低石油价格波动所产生风险非常必要。本文以1987~2021年WTI原油价格为原始数据,利用ARCH族模型对油价波动进行实证分析,研究表明石油价格波动具有肥尾分布和波动率聚类的特征且具有均值回归的倾向,当面对“黑天鹅事件”时能够以较快的速度减小危机带来的冲击,从而得出石油价格波动在突发情形下具有较大弹性的一般结论,并基于此提出完善市场机制作为主要政策实施方向和发展石油期货期权等衍生产品的政策建议,从而减小经济发展的不确定性风险。 展开更多
关键词 arch模型 油价波动 不确定性风险 异方差 能源安全
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Deformation critical threshold estimation of Xiaowan ultrahigh arch dam with time-varying grey model
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作者 Er-feng Zhao Bo Li +1 位作者 Hao Chen Bing-bing Nie 《Water Science and Engineering》 EI CAS CSCD 2023年第3期302-312,共11页
The structural behavior of the Xiaowan ultrahigh arch dam is primarily influenced by external loads and time-varying characteristics of dam concrete and foundation rock mass during long-term operation. According to ov... The structural behavior of the Xiaowan ultrahigh arch dam is primarily influenced by external loads and time-varying characteristics of dam concrete and foundation rock mass during long-term operation. According to overload testing with a geological model and the measured time series of installed perpendicular lines, the space and time evolution characteristics of the arch dam structure were analyzed, and its mechanical performance was evaluated. Subsequently, the deformation centroid of the deflective curve was suggested to indicate the magnitude and unique distribution rules for a typical dam section using the measured deformation values at multi-monitoring points. The ellipse equations of the critical ellipsoid for the centroid were derived from the historical measured time series. Hydrostatic and seasonal components were extracted from the measured deformation values with a traditional statistical model, and residuals were adopted as a grey component. A time-varying grey model was developed to accurately predict the evolution of the deformation behavior of the ultrahigh arch dam during future operation. In the developed model, constant coefficients were modified so as to be time-dependent functions, and the prediction accuracy was significantly improved through introduction of a forgetting factor. Finally, the critical threshold was estimated, and predicted ellipsoids were derived for the Xiaowan arch dam. The findings of this study can provide technical support for safety evaluation of the actual operation of ultrahigh arch dams and help to provide early warning of abnormal changes. 展开更多
关键词 arch dam Deformation behavior EVOLUTION Critical threshold Grey model
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Dynamic soil arching in piled embankment under train load of high-speed railways
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作者 Niu Tingting Yang Yule +2 位作者 Ma Qianli Zou Jiuqun Lin Bin 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第3期719-730,共12页
Piled embankments have many advantages that have been applied in high-speed railway construction engineering.However,the load transfer mechanism of piled embankments,such as soil arching and tension membranes,is still... Piled embankments have many advantages that have been applied in high-speed railway construction engineering.However,the load transfer mechanism of piled embankments,such as soil arching and tension membranes,is still unclear,especially under dynamic loads.To investigate the soil arching and tension membrane under dynamic train loads on high-speed railways,a large-scale piled embankment model test with X-shaped piles as vertical reinforcement was performed,in which twenty-eight earth pressure cells were installed in the piled embankment and an M-shaped wave was adopted to simulate the high-speed railway train load.The results show that dynamic soil arching only occurs when two bogies of a carriage pass by and disappears at other times.The dynamic soil arching and membrane effect are the most significant under the concrete base.The arching height,stress concentration ratio and pile-soil load sharing ratio have a minimal value at 25 Hz.The dynamic soil arching degrades severely at 25 Hz,whose height at 25 Hz is only 0.35 times that at 5 Hz.The arching height fluctuates over a narrow range with increasing loading amplitude.The stress concentration ratio and the pile-soil load sharing ratio increase monotonically as the loading amplitude increases. 展开更多
关键词 dynamic soil arching membrane effect piled embankment train load model test
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基于ARCH类模型的农产品价格波动特征研究
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作者 王溯 胡长情 陈健(指导) 《中国林业经济》 2023年第2期80-84,共5页
基于2011年1月至2022年8月的月度价格指数,运用自回归条件异方差ARCH类模型对猪肉、牛肉、棉花、大豆、稻谷、羊肉六种农产品进行价格波动特征分析研究。结果表明:具有较为显著的ARCH效应是牛肉、大豆、猪肉、棉花这四种农产品;其中农... 基于2011年1月至2022年8月的月度价格指数,运用自回归条件异方差ARCH类模型对猪肉、牛肉、棉花、大豆、稻谷、羊肉六种农产品进行价格波动特征分析研究。结果表明:具有较为显著的ARCH效应是牛肉、大豆、猪肉、棉花这四种农产品;其中农产品价格具有波动集聚性特征的是牛肉、大豆、猪肉、棉花;牛肉、大豆、猪肉、棉花价格不具备高风险和高报酬的特征;农产品价格均具有非对称性是棉花、大豆、猪肉。基于研究分析结果,本文提出相关政策建议,为农产品市场价格调控提供参考。 展开更多
关键词 农产品 价格波动特征 arch类模型
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基于马尔科夫转换ARCH模型的房地产市场波动研究——以房地产市场景气指数为例 被引量:1
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作者 顾稚平 《现代商业》 2023年第2期49-52,共4页
近年来,我国房价波动较大,房地产投机现象时有发生。因此,研究房地产市场的运行规律,对于预测房价、防范房地产泡沫具有重要意义。本文研究了中国住房市场的波动状态。使用ARCH和GARCH模型来寻找房地产市场景气指数随时间变化的证据。... 近年来,我国房价波动较大,房地产投机现象时有发生。因此,研究房地产市场的运行规律,对于预测房价、防范房地产泡沫具有重要意义。本文研究了中国住房市场的波动状态。使用ARCH和GARCH模型来寻找房地产市场景气指数随时间变化的证据。然后利用马尔科夫转移模型(MS模型)连续分析2000年~2021年中国住房市场波动状态的动态。结果表明,中国住房市场存在低波动性、中波动性和高波动性三种状态。实证分析发现,2002年之前,房地产市场一直处于低波动状态,2002年以后,房地产市场在中波动状态和高波动状态来回转换,针对每一个波动拐点,也可以找到当年政府发布的与房地产市场相关的政策,这在一定程度也说明政府行为对房地产市场常起导向作用。本文以房地产市场景气指数为数据,运用EViews和MATLAB进行实践操作,对研究问题进行求解,目的是了解中国房地产市场的波动情况,判断房地产市场的稳定性,为相关房地产企业经营决策和政府部门的规范管理提供参考。 展开更多
关键词 国房景气指数 波动性 arch族模型 马尔科夫转移模型
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Comparison of seismic fragility analysis methods for arch dams
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作者 Jin Aiyun Qiu Yixiang Wang Jinting 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第1期173-189,共17页
This study focuses on the seismic fragility analysis of arch dams.The multiple stripe analysis(MSA),cloud analysis(CLA),and incremental dynamic analysis(IDA)methods are compared.A comprehensive dam-reservoir-foundatio... This study focuses on the seismic fragility analysis of arch dams.The multiple stripe analysis(MSA),cloud analysis(CLA),and incremental dynamic analysis(IDA)methods are compared.A comprehensive dam-reservoir-foundation rock system,which considers the opening of contraction joints,the nonlinearity of dam concrete and foundation rock,the radiation damping effect of semi-unbounded foundation,and the compressibility of reservoir water,is used as a numerical example.225,80,and 15 earthquake records are selected for MSA,CLA,and IDA,respectively.The results show that MSA provides satisfactory fragility analysis,while both CLA and IDA have assumptions that may lead to deviations.Therefore,MSA is the most reliable method among the three methods and is recommended for the fragility analysis of arch dams.It is also shown that the choice of demand level affects the reliability of fragility curves and the effect of the material uncertainty on the fragility of the dam is not significant. 展开更多
关键词 arch dam seismic fragility analysis cloud analysis incremental dynamic analysis multiple stripe analysis
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Predictive value of the trans-perineal three-dimensional ultrasound measurement of the pubic arch angle for vaginal delivery
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作者 Zhu-Wei Liang Wan-Li Gao 《World Journal of Clinical Cases》 SCIE 2023年第20期4874-4882,共9页
BACKGROUND Numerous variables are linked to the success of vaginal delivery,including the subpubic arch angle(SPAA)during labor,the importance of which has not yet been fully elucidated.AIM To examine the SPAA distrib... BACKGROUND Numerous variables are linked to the success of vaginal delivery,including the subpubic arch angle(SPAA)during labor,the importance of which has not yet been fully elucidated.AIM To examine the SPAA distributional characteristics and to ascertain SPAA’s ability to predict the type and duration of labor.METHODS We determined the SPAA and analyzed the corresponding data.We also evaluated the relationship between the SPAA and the mode of delivery and the duration of labor by regression.The present study comprised a total of 301 pregnant women who had given birth at Beijing Tiantan Hospital of the Capital Medical University between January and December of 2021.RESULTS Our analysis of 301 pregnant women revealed that the SPAA measured using three-dimensional trans-perineal ultrasound had a minimum angle of 81°and a maximum angle of 122.2°.The angle in the normal vaginal delivery group was greater than that in the labor cesarean group(P=0.000).The SPAA was a highly significant positive predictor of normal vaginal delivery(P=0.000)with an area under the curve of 0.782(P=0.000;95%CI:0.717-0.848).We found the length of the second stage of labor to be positively influenced by the SPAA using linear regression analysis(P=0.045).CONCLUSION The SPAA was a highly significant positive predictor of normal vaginal delivery.The length of the second stage of labor and normal vaginal birth were predicted by SPAA. 展开更多
关键词 Three-dimensional ultrasound Subpubic arch angle Trans-perineal Vaginal delivery
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基于GARCH族模型人民币离岸价格收益率波动预测分析
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作者 耿春燕 《统计学与应用》 2023年第6期1667-1674,共8页
我国是个外贸依存度很高的国家,汇率的较大波动会对我国经济造成重大影响,准确预测汇率波动性能够为降低中国企业的外贸、投资的汇率风险规避提供一定的参考价值。因此,本文选取了2022年1月3日~2023年7月15日香港美元人民币市场的每日... 我国是个外贸依存度很高的国家,汇率的较大波动会对我国经济造成重大影响,准确预测汇率波动性能够为降低中国企业的外贸、投资的汇率风险规避提供一定的参考价值。因此,本文选取了2022年1月3日~2023年7月15日香港美元人民币市场的每日收盘价格,用2022年1月3日至2022年6月30日的样本内数据建模,并用模型进行2023年7月3日至2023年7月21日的样本外预测以评价模型的预测能力。研究结果显示,IGARCH模型是数据拟合模型最优的,反映了人民币离岸价格收益波动率受冲击影响持久。 展开更多
关键词 收益率波动 arch效应 Garch族模型 预测能力
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Persistent left superior vena cava in right hemiarch replacement under deep hypothermic circulatory arrest:A case report
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作者 Ze-Yu Mi Gang He +1 位作者 Hong-Li Gao Chao Li 《World Journal of Clinical Cases》 SCIE 2023年第32期7858-7864,共7页
BACKGROUND Persistent left superior vena cava(PLSVC),a relatively rare thoracic vascular malformation,can inconvenience perfusionists and operators when encountered during deep hypothermic circulatory arrest(DHCA).CAS... BACKGROUND Persistent left superior vena cava(PLSVC),a relatively rare thoracic vascular malformation,can inconvenience perfusionists and operators when encountered during deep hypothermic circulatory arrest(DHCA).CASE SUMMARY Herein,we describe the case of a patient with concurrent giant aortic arch aneurysm,aortic stenosis,and PLSVC.To treat these conditions,we performed right hemiarch and aortic valve replacements under DHCA.Notably,we applied“bilateral superior vena cava retrograde cerebral perfusion(RCP)”for cerebral protection,which significantly optimized the surgical procedure and reduced the risk of postoperative complications.The patient was discharged 14 d after surgery with no complications.CONCLUSION Surgical intervention for PLSVC under DHCA can be performed using the bilateral superior vena cava RCP approach. 展开更多
关键词 Persistent left superior vena cava Aortic arch aneurysm Hemiarch replacement Deep hypothermic circulatory arrest Retrograde cerebral perfusion Case report
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一类双函数系数ARCH-M模型的经验似然估计
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作者 姜茜 赵培信 《重庆工商大学学报(自然科学版)》 2023年第2期106-112,共7页
针对一类双函数系数自回归条件异方差-均值(ARCH-M)模型的估计问题,提出一种基于经验似然的估计方法;在该估计方法中,所提出的模型允许金融时间序列的风险效应和收益效应同时为某一变量的函数结构,可以有效地刻画金融时间序列的风险和... 针对一类双函数系数自回归条件异方差-均值(ARCH-M)模型的估计问题,提出一种基于经验似然的估计方法;在该估计方法中,所提出的模型允许金融时间序列的风险效应和收益效应同时为某一变量的函数结构,可以有效地刻画金融时间序列的风险和平均收益之间的关系,具有较广的适应性;同时,与经典矩估计法和极大似然估计法相比,基于经验似然的估计方法具有独特的优势,可以充分考虑金融序列的异方差性,并且所构造的置信区间不涉及任何渐近方差的估计,因此具有较好的稳健性和有效性;在一些正则条件下,对所构造的经验对数似然比统计量及函数系数估计量的渐近分布进行了理论分析;结果表明:关于风险效应函数系数和收益效应函数系数的经验对数似然比统计量均渐近收敛于中心卡方分布,同时函数系数估计量渐近收敛于正态分布;进而对风险效应函数系数和收益效应函数系数分别构造了相应函数系数的逐点置信区间。 展开更多
关键词 函数系数模型 arch-M模型 经验似然 置信区间
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瓮马铁路乌江特大桥设计关键技术研究 被引量:1
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作者 王小飞 张杰 +2 位作者 王新国 周继 罗春林 《铁道标准设计》 北大核心 2024年第3期91-98,共8页
新建瓮马铁路乌江特大桥跨越两山之间深谷,地形复杂、设计难度大。为研究该桥梁方案,首先阐述了主桥的方案构思和结构设计,然后通过空间有限元软件对本桥进行静、动力仿真分析,总结了大跨铁路劲性骨架混凝土拱桥构造和受力特性。结果表... 新建瓮马铁路乌江特大桥跨越两山之间深谷,地形复杂、设计难度大。为研究该桥梁方案,首先阐述了主桥的方案构思和结构设计,然后通过空间有限元软件对本桥进行静、动力仿真分析,总结了大跨铁路劲性骨架混凝土拱桥构造和受力特性。结果表明:主跨337 m上承式劲性骨架混凝土拱桥具有刚度大、徐变小、后期养护维修工作量小等优点,主拱圈采用小矢跨比设计,兼顾安全、经济、环保和美观,能够满足铁路桥梁跨越山区“V”形峡谷的要求;主拱圈由劲性钢管混凝土骨架外包C55无收缩混凝土构成,通过分层分段浇筑方案改善拱圈各构件的内力;拱上结合梁采用两片工字形钢与混凝土桥面板相结合的形式,钢梁栓焊结合,便于制造、运输和施工;拱座采用梯形断面扩大基础,基础开挖永临结合,有效降低施工风险;数值分析表明该桥结构的刚度、强度、稳定性均能满足规范要求,能够满足客货共线铁路的安全性和乘坐舒适性要求。可为其他山区铁路桥梁桥式研究提供参考。 展开更多
关键词 山区铁路 铁路桥 钢管混凝土劲性骨架拱桥 数值计算 设计
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股票市盈率波动有偏性对投资者股票交易量的影响研究--基于沪深300指数
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作者 江海潮 范晨宇 《衡阳师范学院学报》 2024年第2期54-60,共7页
有着独特波动规律的股票市盈率,会对投资者的股票交易产生影响。从市盈率波动有偏性的角度出发,以沪深300指数的市盈率数据为研究样本,构建回归模型,实证检验市盈率波动有偏性对股票交易量的影响,结果表明:沪深300指数市盈率波动相对于... 有着独特波动规律的股票市盈率,会对投资者的股票交易产生影响。从市盈率波动有偏性的角度出发,以沪深300指数的市盈率数据为研究样本,构建回归模型,实证检验市盈率波动有偏性对股票交易量的影响,结果表明:沪深300指数市盈率波动相对于正常波动水平存在明显右偏性;沪深300指数市盈率波动的持续时间较长且具有非对称性;沪深300指数市盈率波动右偏性对股票成交量具有显著的反向影响,并且这种影响受到经济增长、出口量、利率、汇率、居民消费价格指数和货币供应量的非对称约束。要稳定股市交易量,就需要综合考虑上述因素的影响,并根据市场变动灵活调整政策措施。 展开更多
关键词 市盈率 交易量 波动有偏性 arch模型
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大倾角钢箱提篮拱桥总体设计
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作者 陈楚龙 吴晓勤 +1 位作者 刘新华 朱玉 《世界桥梁》 北大核心 2024年第1期13-18,共6页
考虑施工技术、经济性和景观效果等方面,陕西蔡家坡渭河特大桥主桥采用(35+210+35) m大倾角钢箱提篮拱桥。该桥采用摩擦摆和环向钢丝绳阻尼支座综合减隔震约束体系,以降低结构的地震响应。拱肋为单室等宽钢箱截面,采用主、副拱肋2条悬链... 考虑施工技术、经济性和景观效果等方面,陕西蔡家坡渭河特大桥主桥采用(35+210+35) m大倾角钢箱提篮拱桥。该桥采用摩擦摆和环向钢丝绳阻尼支座综合减隔震约束体系,以降低结构的地震响应。拱肋为单室等宽钢箱截面,采用主、副拱肋2条悬链线,主、副拱肋共面,设计为横向内倾20°的大倾角,在提高桥梁景观效果的同时,又有效提高了结构的整体稳定性;拱肋设钢-混结合段连接拱脚与混凝土拱座。桥面系采用自重较轻的正交异性钢桥面板结构。吊杆采用抗拉强度1 860 MPa的环氧柔性钢绞线。基础采用Φ2.5 m的钻孔灌注群桩,以抵抗软弱地质条件下荷载的竖向及水平作用力。该桥总体采用先梁后拱的施工方案。整体及局部有限元分析结果表明,桥梁结构力学性能均满足规范要求,设计安全可靠。 展开更多
关键词 钢箱提篮拱桥 大倾角拱肋 减隔震约束体系 正交异性板 群桩基础 先梁后拱 桥梁设计
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Comparison and Selection of Arch-Rib Construction Schemes for Continuous Beam arch Composite Bridge of High Speed Railway
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作者 ZHOU Weiming ZHENG Mingda(Translated) 《Chinese Railways》 2023年第2期35-43,共9页
The paper summarizes the four different construction schemes based on engineering cases for the arch rib construction of continuous beam-arch composite bridges for high-speed railways.These methods include in-situ ass... The paper summarizes the four different construction schemes based on engineering cases for the arch rib construction of continuous beam-arch composite bridges for high-speed railways.These methods include in-situ assembly,segmental lifting,incremental launching and longitudinal moving,and vertical rotation.The temporary structural designs,process methods,and technological equipment for each construction scheme are described in detail.The advantages and disadvantages of each scheme and its application scope under various conditions are analyzed,and opinions and suggestions for guiding the application of each scheme are proposed.The comparison and selection analyses show that the four arch rib construction schemes have certain applicability under different conditions such as bridge site status,bridge span,and construction environment.With the continuous increase of bridge span and progress of construction technological equipment,the arch rib construction technology is developing towards the overall erection direction.This leads to more obvious technical advantages of the segmental lifting method,incremental launching and longitudinal moving method,and vertical rotation method.Therefore,it is necessary to select the best construction scheme according to the construction status and technical conditions during application. 展开更多
关键词 high-speed railway(HSR) continuous beam-arch composite bridge arch rib in-situ assembly segmental lifting incremental launching and longitudinal moving vertical rotation
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