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The prediction of external flow field and hydrodynamic force with limited data using deep neural network

水动力学研究与进展B辑:英文版 2023年第3期35卷 549-570页

作者： Tong-sheng Wang guang xi Zhong-guo sun Zhu Huang School of Energy and Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Predicting the external flow field with limited data or limited measurements has attracted long-time interests of researchers in many industrial applications.Physics informed neural network(PINN)provides a seamless framework for combining the measured data with the deep neural network,making the neural network capable of executing certain physical constraints.Unlike the data-driven model to learn the end-to-end mapping between the sensor data and high-dimensional flow field,PINN need no prior high-dimensional field as the training dataset and can construct the mapping from sensor data to high dimensional flow field directly.However,the extrapolation of the flow field in the temporal direction is limited due to the lack of training data.Therefore,we apply the long short-term memory(LSTM)network and physics-informed neural network(PINN)to predict the flow field and hydrodynamic force in the future temporal domain with limited data measured in the spatial domain.The physical constraints(conservation laws of fluid flow,e.g.,Navier-Stokes equations)are embedded into the loss function to enforce the trained neural network to capture some latent physical relation between the output fluid parameters and input tempo-spatial parameters.The sparsely measured points in this work are obtained from computational fluid dynamics(CFD)solver based on the local radial basis function(RBF)method.Different numbers of spatial measured points(4–35)downstream the cylinder are trained with/without the prior knowledge of Reynolds number to validate the availability and accuracy of the proposed approach.More practical applications of flow field prediction can compute the drag and lift force along with the cylinder,while different geometry shapes are taken into account.By comparing the flow field reconstruction and force prediction with CFD results,the proposed approach produces a comparable level of accuracy while significantly fewer data in the spatial domain is needed.The numerical results demonstrate that the proposed approach with a spe

关键词： Flow field prediction hydrodynamic force prediction long short-term memory physics informed neural network limited data local radial basis function method

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Role of carbon in modifying solidification and microstructure of a Ni?based superalloy with high Al and Ti contents

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Journal of Iron and Steel Research(International) 2021年第1期28卷 98-110页

作者： guang‑di Zhao xi‑min Zang Wen‑ru sun School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina Institute of Metal Research Chinese Academy of SciencesShenyang 110016LiaoningChina

The effect of carbon ranging from 0.014 to 0.071 wt.%on the solidification and microstructure of a Ni-based superalloy with high Al and Ti contents was studied.The results show that the increase in carbon addition significantly increases the size and volume fraction of MC carbides and promotes the change of their morphology from blocky to elongated shape.However,the carbon addition obviously decreases the size and volume fraction of eutectic(γ+γ′)and reducesηphase and borides formation.The change in carbide characteristics is mainly because of the increasing carbide-forming element and carbides precipitation temperature with the increase in carbon which favors the growth of them along the interdendritic liquid film.MC carbides are formed at an earlier solidification stage than the eutectic(γ+γ′).The increased carbide formation consumes more Ti,which delays and reduces the eutectic(γ+γ′)precipitation.The delay of eutectic(γ+γ′)precipitation leads to a deeper undercooling,which significantly decreases the critical Ti concentration for its precipitation.This,in turn,lowers Ti/Al ratio in residual liquids ahead of the eutectic(γ+γ′)and hence reducesηformation subsequently.B and Zr are slightly enriched in the carbides,which are considered during discussing how carbon influences the eutectic(γ+γ′)precipitation.

关键词： Carbon Ni-based superalloy Solidification Segregation Eutectic(γ+γ′) MC carbide

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Experimental investigation of transient characteristics of mild surge and diffuser rotating stall in a centrifugal compressor with vaned diffuser

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Science China(Technological Sciences) 2020年第7期63卷 1212-1223页

作者： ZHAO Yang xi guang ZOU HanSen sun Ya Wei WANG ZhiHeng National Engineering Research Centre of Fluid Machinery&Compressors Xi’an Jiaotong UniversityXi'an 710049China

The centrifugal compressor is widely used for gas compression in various industrial fields such as aero-engine, gas turbine and turbocharger. However, the stable operating range is usually restricted by the occurrence of flow instability such as stall and surge. The paper experimentally examines the developing process of surge and stall occurring in a centrifugal compressor to advance the understanding on flow mechanism of flow instability. It is found that three types of pressure fluctuation can be observed at low flowrate region. At the critical point, the local stall firstly occurs in some specific diffuser passages and the enlarged local diffuser stall eventually induces the mild surge of compression system indicated by the sinusoidal pressure fluctuation. At lower mass flow rate, the diffuser stall cell begins to circumferentially propagate along the impeller rotating direction at 11% of rotor speed with the existence of mild surge. In comparative analysis of IGV pre-swirl angle on the occurrence of mild surge, the mild surge still occurs at the operating condition when the slope of the characteristic map of test stage is still obviously negative, in which the compression system is supposed to be stable in previous study. And a new suggested criterion for the prediction of mild surge is demonstrated that the occurrence of mild surge depends on the destabilization effect of downstream components about diffuser and volute. Combined with the experimental data, the streamwise distribution characteristic of diffuser stall can be used to develop the simplified model of lumped parameters for the analysis on the generation mechanism of the diffuser rotating stall. The quantitative investigation on the relation between the pressure-rise characteristic of subcomponents and the occurrence of mild surge and diffuser rotating stall not only advances the prediction of stability limit but also lays the theoretic foundation for controlling these unsteady behaviors to improve the operating range.

关键词： centrifugal compressor mild surge diffuser rotating stall transient measurement

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The safety of radium-223 combined with new-generation hormonal agents in bone metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis

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Asian Journal of Andrology 2023年第4期25卷 441-447页

作者： Ming-Hao Wang Jin-Dong Dai xing-Ming Zhang Jin-Ge Zhao Guang-Xi Sun Yu-Hao Zeng Hong Zeng Nan-Wei Xu Hao Zeng Peng-Fei Shen Department of Urology West China Hospital of Sichuan UniversityChengdu 610041China

Patients with bone metastatic castration-resistant prostate cancer (mCRPC) might benefit from radium-223 (^(223)Ra) combined withnew-generation hormonal agents (NHAs) in terms of survival and quality of life (QoL). However, the safety of combination therapiesremains unclear. Therefore, we aimed to perform a network meta-analysis by reviewing the literature about the combination of^(223)Ra with abiraterone acetate plus prednisone (AAP) or enzalutamide and to evaluate the safety of combination therapy in bonemCRPC patients. Ultimately, ten studies (2835 patients) were selected, including four randomized controlled trials (RCTs), fiveretrospective cohort studies, and one single-arm study. Overall, there was no difference in the incidence of fracture between the^(223)Ra+NHA combination group and the ^(223)Ra monotherapy group (odds ratio [OR]: 1.46, 95% confidence interval [CI]: 0.91–2.34,P = 0.66), but the incidences in both the ^(223)Ra+NHA combination group (OR: 3.22, 95% CI: 2.24–4.63, P < 0.01) and the ^(223)Ramonotherapy group (OR: 2.24, 95% CI: 1.23–4.08, P < 0.01) were higher than that in the NHA monotherapy group. However, inthe meta-analysis involving only RCTs, there was no difference between the ^(223)Ra monotherapy group and the NHA monotherapygroup (OR: 1.14, 95% CI: 0.22–5.95, P = 0.88), while the difference between the ^(223)Ra+NHA combination group and the NHAmonotherapy group remained significant (OR: 3.22, 95% CI: 2.24–4.63, P < 0.01). Symptomatic skeletal events (SSEs), SSE-freesurvival (SSE-FS), all grades of common adverse events (AEs), and ≥grade 3 AEs among all groups did not show any significantdifference. Our results indicate that the combination of ^(223)Ra with NHAs was well tolerated in bone mCRPC patients compared to ^(223)Ra monotherapy, even though the incidence of fracture was higher in patients who received ^(223)Ra than that among those whoreceived NHA monotherapy. More evidence is needed to explore the safety and efficiency of ^(223)Ra combination therapies.

关键词： meta-analysis metastatic castration-resistant prostate cancer new-generation hormonal agents radium-223 safety

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Equicontinuity of Maps on a Dendrite with Finite Branch Points

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Acta Mathematica Sinica,English Series 2017年第8期33卷 1125-1130页

作者： Tai xiang sun guang Wang SU Hong Jian xi xin KONG College of Information and Statistics Guangxi University of Finance and Economics College of Mathematics and Information Science Guangxi University

Let （T, d） be a dendrite with finite branch points and f be a continuous map from T to T. Denote by w（x, f） and P（f） the w-limit set of x under f and the set of periodic points of f, respectively. Write Ω（x, f） = {yl there exist a sequence of points xk ∈ T and a sequence of positive integers n1 〈 n2 〈 … such that lim k→∞ Xk = X and lim k→∞ f nk （xk） = y}. In this paper, we show that the following statements are equivalent：（1） f is equicontinuous. （2） w（x, f） = Ω（x, f） for any x ∈ T. （3） ∩ ∞ n=1 f n（T） = P（f）, and w（x, f） is a periodic orbit for every x ∈ T and map h： x → w（x, f）（x ∈ T） is continuous. （4） Ω（x, f） is a periodic orbit for any x ∈ T.

关键词： Dendrite map equicontinuity periodic point ε-limit set

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交叉学科背景下国家安全学学科人才培养路径研究

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情报科学 2022年第10期40卷 60-66页

作者：孙曙光肖晞吉林大学研究生院吉林长春130012 吉林大学公共外交学院国家发展与安全研究院吉林长春130012

【目的/意义】人才培养是交叉学科建设的核心任务,针对目前对国家安全学人才培养系统性研究不足的问题,以国家安全学学科建设为切入点,聚焦国家安全学人才培养的理论和实践,以期为学科建设与人才培养提供思路。【方法/过程】坚持理论体... 详细信息

【目的/意义】人才培养是交叉学科建设的核心任务,针对目前对国家安全学人才培养系统性研究不足的问题,以国家安全学学科建设为切入点,聚焦国家安全学人才培养的理论和实践,以期为学科建设与人才培养提供思路。【方法/过程】坚持理论体系探究和实践探索相结合,从三个维度提出国家安全学的理论分析框架,指出其具有的鲜明学科特征;对吉林大学国家安全学学科的方向凝练、平台建设、人才培养、队伍构建等实践方面进行了有益探索。【结果/结论】探讨了国家安全学人才培养体系的建构路径,提出在坚持学科育人导向的逻辑前提下,加快推进学科的“再学科化”,树立交叉融合育人理念,深化课程结构性变革;优化交叉学科组织形式,营造交叉学科人才培养氛围。【创新/局限】以探讨学科形成机理为基础,提出国家安全学人才培养的系统性举措。研究对象的比较与借鉴、国际视角相对缺失。

关键词：交叉学科国家安全学人才培养吉林大学路径遵循

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Clinical and oncologic findings of extraprostatic extension on needle biopsy in de novo metastatic prostate cancer

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Asian Journal of Andrology 2020年第4期22卷 427-431页

作者： Jun-Ru Chen Jin-Ge Zhao Sha Zhu Meng-Ni Zhang Ni Chen Jian-Dong Liu Guang-Xi Sun Peng-Fei Shen Hao Zeng Department of Urology Institute of UrologyWest China HospitalSichuan UniversityChengdu 610041China Department of Pathology West China HospitalSichuan UniversityChengdu 610041China

This study aimed to explore the clinical and oncologic findings in patients with de novo metastatic prostate cancer(mPCa)and extraprostatic extension(EPE)on biopsy.We retrospectively evaluated data on 630 patients with de novo mPCa between January 2009 and December 2017 in the West China Hospital(Chengdu,China),including evaluating the relationships between EPE and other variables and the association of EPE with survival outcomes by the Chi-square test,Kaplan–Meier curves,and the Cox proportional-hazards model.EPE was found in 70/630 patients,making a prevalence of 11.1%.The presence of EPE on biopsy was associated with higher Gleason scores and higher incidence of neuroendocrine differentiation(NED),intraductal carcinoma of the prostate(IDC-P),and perineural invasion(PNI).Compared with those without EPE,patients with EPE had shorter castration-resistant prostate cancer-free survival(CFS;median:14.1 vs 17.1 months,P=0.015)and overall survival(OS;median:43.7 vs 68.3 months,P=0.032).According to multivariate analysis,EPE was not an independent predictor for survival.Subgroup analyses demonstrated that patients with favorable characteristics,including negative NED or IDC-P status,Eastern Cooperative Oncology Group(ECOG)score<2,and prostate-specific antigen(PSA)<50 ng ml−1,had worse prognoses if EPE was detected.In patients with PSA<50 ng ml−1,EPE was a negative independent predictor for OS(hazard ratio[HR]:4.239,95%confidence interval[CI]:1.218–14.756,P=0.023).EPE was strongly associated with other aggressive clinicopathological features and poorer CFS and OS.These data suggest that EPE may be an indicator of poor prognosis,particularly in patients,otherwise considered likely to have favorable survival outcomes.

关键词： extraprostatic extension metastatic prostate cancer prevalence prognosis

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Bayesian serial revision method for RLLC cluster systems failure prediction

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Journal of Systems Engineering and Electronics 2011年第2期22卷 238-246页

作者： Qiang Liu guang Jin Jinglun Zhou Quan sun Min xi College of Information System and Management National University of Defense Technology Changsha 410073 P. R. China School of Computer Science McGill University Montreal H3A2A7 Canada School of Industrial and Systems Engineering Georgia Institute of Technology Atlanta 303320205 USA Department of Computer Science Xi'an Jiaotong University Xi'an 710049 P. R. China

Failure prediction plays an important role for many tasks such as optimal resource management in large-scale system. However, accurately failure number prediction of repairable large-scale long-running computing （RLLC） is a challenge because of the reparability and large-scale. To address the challenge, a general Bayesian serial revision prediction method based on Bootstrap approach and moving average approach is put forward, which can make an accurately prediction for the failure number. To demonstrate the performance gains of our method, extensive experiments on the data of Los Alamos National Laboratory （LANL） cluster is implemented, which is a typical RLLC system. And experimental results show that the prediction accuracy of our method is 80.2 %, and it is a greatly improvement with 4 % compared with some typical methods. Finally, the managerial implications of the models are discussed.

关键词： failure prediction cluster systems Bayesian approach failure rate.

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Regional location of lymph node metastases predicts survival in patients with de novo metastatic prostate cancer

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Asian Journal of Andrology 2023年第4期25卷 462-467页

作者： Zhi-Peng Wang Jun-Ru Chen Jin-Ge Zhao Sha Zhu xing-Ming Zhang Jia-Yu Liang Ben He Yu-Chao Ni Guang-Xi Sun Peng-Fei Shen Hao Zeng Department of Urology Institute of UrologyWest China HospitalSichuan UniversityChengdu 610041China Department of Urology The Third People’s Hospital of ChengduChengdu 610031China

To report the regional locations of metastases and to estimate the prognostic value of the pattern of regional metastases inmen with metastatic hormone-sensitive prostate cancer (mHSPC), we retrospectively analyzed 870 mHSPC patients betweenNovember 28, 2009, and February 4, 2021, from West China Hospital in Chengdu, China. The patients were initially classifiedinto 5 subgroups according to metastatic patterns as follows: simple bone metastases (G1), concomitant bone and regional lymphnode (LN) metastases (G2), concomitant bone and nonregional LN (NRLN) metastases (G3), lung metastases (G4), and livermetastases (G5). In addition, patients in the G3 group were subclassified as G3a and G3b based on the LN metastatic plane(below or above the diaphragm, respectively). The associations of different metastatic patterns with castration-resistant prostatecancer-free survival (CFS) and overall survival (OS) were analyzed by univariate and multivariate analyses. The results showedthat patients in G1 and G2 had relatively favorable clinical outcomes, patients in G3a and G4 had intermediate prognoses, andpatients in G3b and G5 had the worst survival outcomes. We observed that patients in G3b had outcomes comparable to those inG5 but had a significantly worse prognosis than patients in G3a (median CFS: 8.2 months vs 14.3 months, P = 0.015;medianOS: 38.1 months vs 45.8 months, P = 0.038). In conclusion, metastatic site can predict the prognosis of patients with mHSPC,and the presence of concomitant bone and NRLN metastases is a valuable prognostic factor. Furthermore, our findings indicatethat the farther the NRLNs are located, the more aggressive the disease is.

关键词： lymph node metastases metastatic hormone-sensitive prostate cancer metastatic pattern metastatic site nonregional lymph node metastases staging

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一种适用于粒子法的二维复杂几何形状建模方法

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西安交通大学学报 2023年第7期57卷 160-168页

作者：康江南孙一颉孙中国席光西安交通大学能源与动力工程学院西安710049

为提高无网格法数值计算中固体边界粒子离散的几何精度和均布质量,提出了一种复杂二维形状的边界粒子离散以及内部粒子填充技术。首先,使用整体微调法对单层边界粒子进行离散,再基于多边形偏移原理和圆角化处理实现多层边界粒子均匀布置... 详细信息

为提高无网格法数值计算中固体边界粒子离散的几何精度和均布质量,提出了一种复杂二维形状的边界粒子离散以及内部粒子填充技术。首先,使用整体微调法对单层边界粒子进行离散,再基于多边形偏移原理和圆角化处理实现多层边界粒子均匀布置;然后,使用扫描-等距微调法和粒子补偿法进行粒子初始填充,再通过粒子迁移算法,实现内部粒子均匀填充。通过对多种典型二维复杂形状进行粒子建模和浸没算例的模拟,结果表明:该方法对狭长夹角和任意复杂形状都能实现高精度均匀离散,内部粒子数密度平均值误差低于0.4%;与传统笛卡尔坐标系建模方式相比,使用该方法所建模型对边界的几何描述更加准确,边界周围流体的静压误差不超过6.51%。

关键词：粒子法前处理粒子均匀布置移动粒子半隐式方法粒子迁移

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