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Strain rate response of a Zr-based composite fabricated by Bridgman solidification

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 214-219页

作者： Jun-wei Qiao Yong zhang ji-heng Li guo-liang Chen State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0 bulk metallic glass matrix composites,containingβ-Zr dendrites,were fabricated by Bridgman solidification at the withdrawal velocity of 1.0 mm/s through a temperature gradient of～45 K/*** to the increasing compressive strain rates,the monotonic increasing and decreasing were obtained for the maximum strength and the fracture strain,*** results show that high strain rate may induce the insufficient time for the interaction between shear bands and the crystalline phase,and early fracture occurs as a *** fractographs are consistent with the mechanical properties,and the failure mode of the present Zr-based composites is in agreement with the frame of the ellipse criterion.

关键词： bulk metallic glass composites Bridgman solidification mechanical properties

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餐馆菜肴和家庭菜肴钠、脂肪含量及分布研究

中国健康教育 2024年第1期40卷 36-39页

作者：张继国杜文雯黄绯绯张晓帆李丽张兵王惠君中国疾病预防控制中心营养与健康所北京100050

目的了解我国餐馆菜肴和家庭菜肴钠、脂肪含量及分布情况,为合理膳食提供依据。方法2019—2020年在我国6省192家餐馆以及北京某单位招募志愿者进行家庭烹饪,采集以上途径获得的菜肴。对于有较多汤汁的菜肴,食用部分和非食用部分(油汤)... 详细信息

目的了解我国餐馆菜肴和家庭菜肴钠、脂肪含量及分布情况,为合理膳食提供依据。方法2019—2020年在我国6省192家餐馆以及北京某单位招募志愿者进行家庭烹饪,采集以上途径获得的菜肴。对于有较多汤汁的菜肴,食用部分和非食用部分(油汤)分别采样。全部样品统一送至第三方实验室检测钠和脂肪含量。结果958道餐馆菜肴钠含量中位数为513.0 mg/100 g,220道家庭菜肴钠含量中位数为476.7 mg/100 g;432道餐馆菜肴脂肪含量中位数为11.6 g/100 g,168道家庭菜肴脂肪含量中位数为8.2 g/100 g;568道餐馆菜肴非食用部分钠含量占比为13.8%,133道家庭菜肴非食用部分钠含量占比为19.7%;364道餐馆菜肴非食用部分脂肪含量占比为19.5%,82道家庭菜肴非食用部分脂肪含量占比为11.8%。结论在日常饮食中应避免食用菜肴的油汤,可减少钠和脂肪的摄入;未来应开展健康教育,减少餐馆和家庭烹饪中食盐等调味品和食用油的使用量。

关键词：餐馆家庭菜肴钠脂肪

2018年中国6~17岁儿童青少年宏量营养素摄入与超重/肥胖的关系

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营养学报 2024年第3期46卷 215-219,227页

作者：原晓蓉姜红如魏艳丽王惠君王志宏张兵张继国中国疾病预防控制中心营养与健康所北京100050

目的分析2018年中国15省(自治区、直辖市)6~17岁儿童青少年宏量营养素供能比与超重/肥胖以及身体体质指数(BMI)的关系。方法数据来源于中美合作课题“中国健康与营养调查”和国家财政项目“中国居民营养状况变迁的队列研究”。选取2018... 详细信息

目的分析2018年中国15省(自治区、直辖市)6~17岁儿童青少年宏量营养素供能比与超重/肥胖以及身体体质指数(BMI)的关系。方法数据来源于中美合作课题“中国健康与营养调查”和国家财政项目“中国居民营养状况变迁的队列研究”。选取2018年调查中数据完整的6~17岁儿童青少年1464人。采用连续3 d 24 h膳食回顾法和家庭称重法收集膳食资料。分别采用广义线性回归模型和Logistic回归模型分析宏量营养素摄入与BMI和超重/肥胖的关系。结果2018年儿童青少年超重/肥胖率为22.5%。调整混杂因素后,相较于蛋白质供能比<10%组,12%~15%组(β=0.71,95%CI:0.19,1.22)和≥15%组(β=0.78,95%CI:0.21,1.34)与BMI呈正相关;蛋白质供能比12~15%组(OR=1.47,95%CI:1.01,2.14)和≥15%组(OR=1.58,95%CI:1.06,2.37)超重/肥胖的风险分别增加47%和58%。与碳水化合物供能比<40%组相比,≥55%组(OR=1.47,95%CI:1.02,2.11)超重/肥胖风险增加47%。结论儿童青少年蛋白质和碳水化合物摄入与超重/肥胖和BMI呈正相关。

关键词：儿童青少年超重肥胖宏量营养素

Novel data-driven sparse polynomial chaos and analysis of covariance for aerodynamics of compressor cascades with dependent geometric uncertainties

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Chinese Journal of Aeronautics 2024年第6期37卷 89-108页

作者： Zhengtao guo Wuli CHU Haoguang zhang Tianyuan ji School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China

Polynomial Chaos Expansion(PCE)has gained significant popularity among engineers across various engineering disciplines for uncertainty ***,traditional PCE suffers from two major ***,the orthogonality of polynomial basis functions holds only for independent input variables,limiting the model’s ability to propagate uncertainty in dependent ***,PCE encounters the"curse of dimensionality"due to the high computational cost of training the model with numerous polynomial *** practical manufacturing,compressor blades are subject to machining precision limitations,leading to deviations from their ideal geometric *** deviations require a large number of geometric parameters to describe,and exhibit significant *** efficiently quantify the impact of high-dimensional dependent geometric deviations on the aerodynamic performance of compressor blades,this paper firstly introduces a novel approach called Data-driven Sparse PCE(DSPCE).The proposed method addresses the aforementioned challenges by employing a decorrelation algorithm to directly create multivariate basis functions,accommodating both independent and dependent random ***,the method utilizes an iterative Diffeomorphic Modulation under Observable Response Preserving Homotopy regression algorithm to solve the unknown coefficients,achieving model sparsity while maintaining fitting ***,the study investigates the simultaneous effects of seven dependent geometric deviations on the aerodynamics of a high subsonic compressor cascade by using the DSPCE method proposed and sensitivity analysis of *** joint distribution of the dependent geometric deviations is determined using Quantile-Quantile plots and normal copula functions based on finite measurement *** results demonstrate that the correlations between geometric deviations significantly impact the variance of aerodynamic performance and the flow ***,

关键词： Data-driven sparse polyno-mial chaos Analysis of covariance Dependent uncertainty Aerodynamic performance Compressor cascade

A Scan of Obesogenic Environments and a Spatial Inference of Obesity Prevalence in Chinese Children and Adolescents: Based on the Chinese Health and Nutrition Survey 2011 Data

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Biomedical and Environmental Sciences 2018年第10期31卷 729-739页

作者： guo Chun Lei zhang Bing WANG Hui Jun FENG guo Shuang LI Jun Ming SU Chang zhang ji guo WANG Zhi Hong DU Wen Wen National Institute for Nutrition and Health Chinese Center for Disease Control and Prevention Center for Clinical Epidemiology & Evidence-based Medicine of Beijing Children's Hospital Capital Medical University National Center for Children's Health School of Statistics Shanxi University of Finance and Economics

Objective To identify the characteristics of Chinese obesogenic environments at a provincial level, infer a spatial distribution map of obesity prevalence in 31 provinces, and provide a foundation for development of policy to reduce obesity in children and adolescents. Methods After scanning obesity data on subjects aged 7-17 years from 12 provinces in the China Health and Nutrition Survey 2011 and environmental data on 31 provinces from the China Statistical Yearbook 2011 and other sources, we selected 12 predictors. We used the 12 surveyed provinces as a training sample to fit an analytical model with partial least squares regression and prioritized the 12 predictors using variable importance in projection. We also fitted a predictive model with Bayesian analysis. Results We identified characteristics of obesogenic environments. We fitted the predictive model with a deviance information criterion of 61.96 and with statistically significant（P 〈 0.05） parameter estimates of intercept [95% confidence interval（CI）： 329.10, 963.11], log（oil）（CI： 13.11, 20.30）, log（GDP）（CI： 3.05, 6.93）, log（media）（CI：-234.95,-89.61）, and log（washing-machine）（CI： 0.92, 5.07）. The total inferred average obesity prevalence among those aged 7-17 was 9.69% in 31 Chinese provinces in 2011. We also found obvious clustering in occurrences of obesity in northern and eastern provinces in the predicted map. Conclusion Given complexity of obesity in children and adolescents, concerted efforts are needed to reduce consumption of edible oils, increase consumption of vegetables, and strengthen nutrition, health, and physical activity education in Chinese schools. The northern and eastern regions are the key areas requiring intervention.

关键词： Chinese children Obesity Environment Spatial inference Prevalence

Association of Red Meat Usual Intake with Serum Ferritin and the Risk of Metabolic Syndrome in Chinese Adults: A Longitudinal Study from the China Health and Nutrition Survey

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Biomedical and Environmental Sciences 2020年第1期33卷 19-29页

作者： HUANG Li Na WANG Hui Jun WANG Zhi Hong zhang ji guo jiA Xiao Fang zhang Bing DING Gang Qiang National Institute for Nutrition and Health Chinese Center for Disease Control and PreventionBeijing 100050China

Objective The present study aimed to investigate the association of red meat usual intake with metabolic syndrome(Met S),and explore the contribution of red meat usual intake to serum *** Based on the data from the longitudinal China Health and Nutrition Survey(CHNS),2,797 healthy adults aged 18–75 years without hypertension,diabetes,and Met S were selected in 2009 as subjects and follow-up studies were carried out till *** used the National Cancer Institute(NCI)method to estimate the usual intake of *** logistic regressions were performed to evaluate the association between red meat usual intake and the risk of Met *** regression analysis was used to study the relationship between red meat consumption and serum ferritin *** After adjusting for potential confounders,red meat,and fresh red meat were positively associated with the risk of Met S(RR=1.41,95%CI:1.05–1.90 and RR=1.37,95%CI:1.02–1.85,respectively).These relationships showed increasing trend(P<0.05).The level of serum ferritin increased significantly with the number of Met S components(P<0.05).The quantile regression analysis showed that red meat and fresh red meat usual intake had a significant positive association with serum ferritin levels across the entire conditional serum ferritin distribution(P<0.05).Processed red meat did not exhibit a similar *** Higher red meat usual intake was associated with an increased risk of Met S and elevated serum ferritin levels.

关键词： Usual intake Red meat Metabolic syndrome Serum ferritin

Inverse reliability analysis and design for tunnel face stability considering soil spatial variability

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1552-1564页

作者： Zheming zhang jian ji Xiangfeng guo Siang Huat Goh Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China Department of Civil and Environmental Engineering National University of SingaporeSingapore

The traditional deterministic analysis for tunnel face stability neglects the uncertainties of geotechnical parameters,while the simplified reliability analysis which models the potential uncertainties by means of random variables usually fails to account for soil spatial *** overcome these limitations,this study proposes an efficient framework for conducting reliability analysis and reliability-based design(RBD)of tunnel face stability in spatially variable soil *** three-dimensional(3D)rotational failure mechanism of the tunnel face is extended to account for the soil spatial variability,and a probabilistic framework is established by coupling the extended mechanism with the improved Hasofer-Lind-Rackwits-Fiessler recursive algorithm(iHLRF)as well as its inverse analysis *** proposed framework allows for rapid and precise reliability analysis and RBD of tunnel face *** demonstrate the feasibility and efficacy of the proposed framework,an illustrative case of tunnelling in frictional soils is presented,where the soil's cohesion and friction angle are modelled as two anisotropic cross-correlated lognormal random *** results show that the proposed method can accurately estimate the failure probability(or reliability index)regarding the tunnel face stability and can efficiently determine the required supporting pressure for a target reliability index with soil spatial variability being taken into ***,this study reveals the impact of various factors on the support pressure,including coefficient of variation,cross-correlation between cohesion and friction angle,as well as autocorrelation distance of spatially variable soil *** results also demonstrate the feasibility of using the forward and/or inverse first-order reliability method(FORM)in high-dimensional stochastic *** is hoped that this study may provide a practical and reliable framework for determining the stability of tunnels in complex

关键词： Limit analysis Tunnel face stability Spatial variability HLRF algorithm Inverse reliability method

A New Nonlinear Optical Crystal GdCa_(4)O(BO_(3))_(3)

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Chinese Physics Letters 1999年第3期16卷 184-186页

作者： zhang Shu-jun CHENG Zhen-xiang zhang Shao-jun zhang ji-guo HAN jian-ru CHEN Huan-chu National Laboratory of Crystal Materials Shandong UniversityJi’nan 250100

Large size and high quality single crystals GdCa_(4)O(BO_(3))_(3) have been grown from platinum crucible under air atmosphere by the conventional rf-heating Czochralski *** crystal growth conditions,growth habits,and transmission spectra were *** crystal is transparent in the visible and near-infrared region(320-2600nm).It has a good second harmonic generation phase-matching *** phase-matching experiment result is well consistent with the theoretical *** frequency-doubling efficiency is 26.7% in the phase-matching angles θ=45o and ø=45.1o direction.

关键词： Crystal matching doubling

UAMP-Based Delay-Doppler Channel Estimation for OTFS Systems

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China Communications 2024年第10期21卷 1-15页

作者： Li Zhongjie Yuan Weijie guo Qinghua Wu Nan zhang ji Department of Electronic and Electrical Engineering Southern University of Science and TechonologyShenzhen 518055China School of Electrical Computer and Telecommunications EngineeringUniversity of WollongongWollongongNSW 2522Australia School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China School of Mathematics and Statistics Henan University of Science and TechnologyLuoyang 471000China

Orthogonal time frequency space(OTFS)technique, which modulates data symbols in the delayDoppler(DD) domain, presents a potential solution for supporting reliable information transmission in highmobility vehicular networks. In this paper, we study the issues of DD channel estimation for OTFS in the presence of fractional Doppler. We first propose a channel estimation algorithm with both low complexity and high accuracy based on the unitary approximate message passing(UAMP), which exploits the structured sparsity of the effective DD domain channel using hidden Markov model(HMM). The empirical state evolution(SE) analysis is then leveraged to predict the performance of our proposed algorithm. To refine the hyperparameters in the proposed algorithm,we derive the update criterion for the hyperparameters through the expectation-maximization(EM) algorithm. Finally, Our simulation results demonstrate that our proposed algorithm can achieve a significant gain over various baseline schemes.

关键词： channel estimation hidden Markov model(HMM) orthogonal time frequency space(OTFS) unitary approximate message passing(UAMP)