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the mean value concept in mono-linear regression of multi-variables and its application to trace studies in geosciences

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Science China Earth Sciences 2007年第12期50卷 1828-1834页

作者： A j t jULL NSF-AMS laboratory University of Arizona

the "mean value concept" in a mono-linear regression of multi-variables is *** applications to reconstruction of the past 90-year salinity of the sea surface water in Xisha Islands and to tracing the past 80 ka paleo-geomagnetic events from the Luochuan loess 10Be record are introduced in detail,which show the significance and the potential of the "mean value concept" in geoscience research.

关键词： mean value concept, linear regression, trace, reconstruction

Effect of surface layer softening from previous electrochemical corrosion on electrochemical cold drawing of Q235 steel bar

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journal of Iron and Steel Research International 2022年第5期29卷 819-835页

作者： j.L.Guo t.j.Chen State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou730050GansuChina

the effects of H_(2)SO_(4)concentration and current in electrochemical corrosion on surface layer softening or plasticizing of Q235 steel bar and their effects on subsequent electrochemical cold drawing(ECD)were *** results indicate that the electrochemical corrosion can soften or plasticize the surface layer of Q235 steel bar and then make the subsequent ECD be conducted more *** softening degree and thickness of the surface layer are continuously enhanced with increasing corrosion rate,i.e.,increasing H_(2)SO_(4)concentration or current,due to the generation of more vacancy clusters in deeper regions of surface *** vacancy clusters then relax dislocations through being absorbed during ECD,and the formation and movement of additional dislocation flux are thereby enhanced,resulting in the further obvious decrease in the drawing *** is also due to the enhanced formation and movement of additional dislocation flux that the dislocation density and thus the hardness of the surface layer are decreased,as well as that the texture structure is *** behaviors are enhanced as the corrosion rate increases.

关键词： Electrochemical corrosion Electrochemical cold drawing Surface layer softening Vacancy Additional dislocation flux

Performance and Internal Flow of Sirocco Fan Using Contra-Rotating Rotors

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journal of thermal Science 2008年第1期17卷 35-41页

作者： j.Fukutomi t.Shigemitsu t.Yasunobu Institute of Science and technology The University of Tokushima2-1 Minamijyosanjima-choTokushima 770-8506JAPAN Institute of Science and technology The University of Tokushima2-1 Minamijyosanjima-choTokushima 770-8506JAPAN Research Associate Graduate School of Advanced technology and Science The University of Tokushima2-1 Minamijyosanjima-choTokushima 770-8506JAPAN

A sirocco fan using contra-rotating rotors in which an inner rotor is settled inside the sirocco fan rotor and each rotor rotates in an opposite direction was proposed for the purpose of getting the higher pressure and making the structure of a sirocco fan more compact. If the high discharge pressure is obtained with the adoption of the contra-rotating rotors, it could be used for various purposes. Pressure coefficient of a sirocco fan with contra-rotating rotors is 2.5 times as high as the conventional sirocco fan and the maximum efficiency point of contra-rotating rotors shifts to larger flow rate than a conventional sirocco fan. On the other hand, it was clarified from the flow measurement results that circumferential velocity component at the outlet of the outer rotor of contra-rotating ro- tors becomes larger than a conventional one. In the present paper, the performance of a conventional sirocco fan and a sirocco fan with contra-rotating rotors are shown and the internal flow field at the outlet of outer rotor of both cases is clarified. then, the effect of different kind of contra-rotating rotors on the performance and internal flow field is investigated and the rotor design with higher performance would be discussed.

关键词： Sirocco fan High pressure Contra-rotating rotors Slow angle Circular arc blade Aerofoil blade

疱疹早期应用度洛西汀预防带状疱疹后神经痛的疗效:一项随机对照研究

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中国疼痛医学杂志 2025年第1期31卷 13-14页

作者： Zhao C Zhang t Zhu Q 赵春美(译) 不详首都医科大学附属北京天坛医院疼痛科

经典抗焦虑抑郁药物-度洛西汀为带状疱疹后神经痛(postherpetic neuralgia,PHN)的一线治疗药物。本研究首次提出在带状疱疹出疱急性期预防性口服度洛西汀有望预防PHN的发生,纳入疼痛VAS评分≥4、带状疱疹出疱72 h内的750例病人,随机分... 详细信息

经典抗焦虑抑郁药物-度洛西汀为带状疱疹后神经痛(postherpetic neuralgia,PHN)的一线治疗药物。本研究首次提出在带状疱疹出疱急性期预防性口服度洛西汀有望预防PHN的发生,纳入疼痛VAS评分≥4、带状疱疹出疱72 h内的750例病人,随机分为对照组和度洛西汀组。对照组接受常规临床治疗,度洛西汀组在常规治疗基础上口服度洛西汀。主要结局指标为12周时PHN的发生率。次要结局指标包括3、4、8周VAS评分>0的人数,以及4、8、12周VAS评分≥3的人数、生活质量评分、病人总体变化评分、睡眠质量评分等。结果表明,度洛西汀组的PHN发生率与对照组相比无显著差异,度洛西汀组第3、4、8周VAS评分>0的人数,以及4、8和12周VAS评分≥3的人数显著少于对照组。度洛西汀组病人的生活质量评分、病人总体变化评分、睡眠质量评分均显著优于对照组。虽然本研究为阴性结果,但预防性口服度洛西汀仍可以避免5.9%的带状疱疹病人发展成为PHN,因此具有一定的临床意义。

关键词：带状疱疹后神经痛度洛西汀结局指标阴性结果一线治疗药物早期应用随机对照研究带状疱疹病

Stochastic framework for modeling the linear apparent behavior of complex materials:Application to random porous materials with interphases

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Acta Mechanica Sinica 2013年第6期29卷 773-782页

作者： j.Guilleminot t.t.Le C.Soize Universit Paris-Est Laboratoire Modlisation et Simulation Multi EchelleMSME UMR8208 CNRS5 Bd Descartes77454 Marne la ValleFrance

this paper is concerned with the modeling of randomness in multiscale analysis of heterogeneous materials. More specifically, a framework dedicated to the stochastic modeling of random properties is first introduced. A probabilistic model for matrix-valued second-order random fields with symmetry propertries, recently proposed in the literature, is further reviewed. Algorithms adapted to the Monte Carlo simulation of the proposed representation are also provided. the derivations and calibration procedure are finally exemplified through the modeling of the apparent properties associated with an elastic porous microstructure containing stochastic interphases.

关键词： Apparent properties MaxEnt Probabilistic model

two-fluid modelling for cylindrical fluidized beds using kinetic theory for rough spheres

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Particuology 2020年第3期18卷 25-34页

作者： Lei Yang j.t.Padding j.A.M.Kuipers Helmholtz Institute Erlangen-Nürnberg for Renewable Energy(IEK-11) Fürther Straβe 24890429 NurnbergGermany Department of Process and Energy Delft University of Technology2628CB DelftThe Netherlands Department of Chemical Engineering and Chemistry Eindhoven University of Technology5600MB EindhovenThe Netherlands

Recently,we have extended the kinetic theory of granular flow (KtGF) to include friction between the spherical particles and tested it in rectangular *** this study,the extended KtGF implemented in cylindrical coordinates is used to model the more-commonly employed cylindrical bubbling fluidized *** attention is paid to the anti-symmetric part of the velocity gradient in the solids stress *** verification of the implementation,a comparison of the present model in the limit of zero friction with the original (frictionless) KtGF model was ***,simulations of bubbling fluidized beds of inelastic particles were performed using our extended KtGF and an effective KtGF model for inelastic particles of jenkins and *** simulation results show good agreement for the time-averaged solids volume fraction distribution and solids circulation ***,our model is validated by predicting the individual bubble behavior in dense bubbling fluidized beds containing different granular materials in a comparison with experimental data from Verma et al.(2014).the extended KtGF leads to an improved agreement with experimental bubble *** to previous work (Yang et al.,2016b,2017c),and by introducing cylindrical coordinates,the current work demonstrates that the extended KtGF improves predictions for the temporal bubble behavior of cylindrical fluidized beds.

关键词： Fluidization Frictional collision Rough particles Cylindrical bed hydrodynamics two-fluid model

Microstructure and tensile properties of magnesium nanocomposites fabricated using magnesium chips and carbon black

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journal of Magnesium and Alloys 2020年第3期8卷 860-872页

作者： t.j.Lee W.j.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

In this study,carbon black(0,0.01,0.03 and 0.08 wt%)and AZ31(Mg-3Al-lZn)magnesium chips were used to fabricate carbon black-reinforced magnesium matrix composites with extrusion or a combination of extrusion and high-ratio differential speed *** hot pressing at 693 K and extrusion at 623 K with an extrusion ratio of 22,the magnesium chips coated with carbon black were soundly bonded into a bulk composite *** grain sizes of the extruded materials were similar with a size of 48.2-51.5|im despite the difference in the amount of carbon *** yield strength and ultimate tensile strength increased from 177 to 191 MPa and from 240 to 265 MPa,respectively,as a result of the addition of 0.01%carbon black;however,a further increase in the strength was marginal with additional carbon *** same trend was observed in the strain hardening *** tensile elongation increased by to the addition of 0.01%carbon black(from 15.8%to 17.4%)due to the increased work hardening effect,but decreased with additional carbon black due to its agglomeration and poor dispersion at higher *** high-ratio differential speed rolling(HRDSR)on the extruded materials and subsequent annealing,the AZ31 and AZ31 composites had a similar fine grain size of 16.3-17.9 *** annealed HRDSR composites showed the best mechanical properties at a higher content of carbon black(0.03%)compared to that(0.01%)for the extruded *** resulted from the enhanced dispersion effect of the carbon black due to the high shear flow induced during the HRDSR *** extruded composites exhibited the three distinct hardening stages(stage II,stage III and stage IV),while the annealed HRDSR composites mainly displayed the stage III *** addition of carbon black increased the strain hardening rate at all the strain hardening stages in both of the extruded and annealed HRDSR *** the initial hardening stage,the strain hardening rates of the extruded comp

关键词： Recycling Magnesium alloys chips Carbon black Nanocomposites Extrusion Differential speed rolling

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亚洲高山流域千年尺度地表剥蚀的制约因素

中国科学:地球科学 2025年第1期55卷 75-94页

作者：杨业 Steven ABINNIE 徐胜刘丛强 tibor jDUNAI 天津大学地球系统科学学院表层地球系统科学研究院天津300072 Institute of Geology and Mineralogy University of CologneCologne 50674Germany

本研究利用前人1233个亚洲高山流域沉积物宇宙成因核素^(10)Be数据统一计算了地表剥蚀速率,以约束构造、气候和地形如何影响和控制地表剥蚀过程.基于高程数据逐个像元的核素产率,使用蒙特卡洛模拟方法重新计算了^(10)Be流域剥蚀速率.剥... 详细信息

本研究利用前人1233个亚洲高山流域沉积物宇宙成因核素^(10)Be数据统一计算了地表剥蚀速率,以约束构造、气候和地形如何影响和控制地表剥蚀过程.基于高程数据逐个像元的核素产率,使用蒙特卡洛模拟方法重新计算了^(10)Be流域剥蚀速率.剥蚀速率变化范围从(7.4±0.7)mm ka^(-1)(1σ;青藏高原内部)到(9,646744+777)mm ka^(-1)(1σ;青藏高原南部)跨四个数量级,中位数为186mm ka^(-1).逐个像元计算的核素产率与传统模型使用质心坐标和平均高程计算的核素产率相比,后者96.6%核素产率被低估,其中高程差越大越被低估.两种方法计算的产率偏差可达40%,究其原因可能是流域高程分布不均和核素产率随海拔和纬度呈非线性变化.通过量化地表剥蚀速率与构造、气候、地形和岩性之间的相关性将有助于推演未知流域的剥蚀速率.从局部小尺度分析,亚热带台湾岛地区剥蚀速率可能主要受降水和新构造驱动的山体滑坡影响,而降水变化范围较窄的青藏高原东部的剥蚀速率主要受控于地形;冰川覆盖的高原地区剥蚀速率受冰川作用影响,如帕米尔、青藏高原内部和南部地区;青藏高原内部剥蚀速率较低是因为较低的降水和较高的侵蚀基准面,从而限制了河流的下切和地表起伏度演化.与局部小尺度强调单一主控因素不同,本研究对亚洲高山流域宏观大尺度进行量化分析发现:(1)地形指标(包括坡度、地形起伏度和河道陡峭指数)与剥蚀速率在千年尺度呈现一致的幂函数关系,而非简单线性;(2)剥蚀速率与气候(包括与海拔相关的降水、温度和植被覆盖度)和新构造活动(地震核密度分布)呈近似幂函数关系,为次要控制因素;(3)岩性与剥蚀速率没有明显的相关性,可能受限于流域复杂的岩性混合和低分辨率的可侵蚀指数数据.

关键词： 10Be剥蚀速率气候变化构造抬升地形梯度亚洲高山流域

Structural modeling of sandwich structures with lightweight cellular cores

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Acta Mechanica Sinica 2007年第5期23卷 545-559页

作者： t.Liu Z.C.Deng t.j.Lu Department of Engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China MOE Key Laboratory of Strength and Vibration School of AerospaceXi'an Jiaotong UniversityXi'an 710049China

An effective single layered finite element （FE） computational model is proposed to predict the structural behavior of lightweight sandwich panels having two dimensional （2D） prismatic or three dimensional （3D） truss cores. three different types of cellular core topology are considered： pyramidal truss core （3D）, Kagome truss core （3D） and corrugated core （2D）, representing three kinds of material anisotropy： orthotropic, monoclinic and general anisotropic. A homogenization technique is developed to obtain the homogenized macroscopic stiffness properties of the cellular core. In comparison with the results obtained by using detailed FE model, the single layered computational model can give acceptable predictions for both the static and dynamic behaviors of orthotropic truss core sandwich panels. However, for non-orthotropic 3D truss cores, the predictions are not so well. For both static and dynamic behaviors of a 2D corrugated core sandwich panel, the predictions derived by the single layered computational model is generally acceptable when the size of the unit cell varies within a certain range, with the predictions for moderately strong or strong corrugated cores more accurate than those for weak cores.

关键词： Cellular material Sandwich panel Homogenization Finite element