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Universal critical properties of the Eulerian bond-cubic model
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作者 丁成祥 姚桂元 +2 位作者 李崧 邓友金 郭文安 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第7期1-8,共8页
We investigate the Eulerian bond-cubic model on the square lattice by means of Monte Carlo simulations, using an efficient cluster algorithm and a finite-size scaling analysis. The critical points and four critical ex... We investigate the Eulerian bond-cubic model on the square lattice by means of Monte Carlo simulations, using an efficient cluster algorithm and a finite-size scaling analysis. The critical points and four critical exponents of the model are determined for several values of n. Two of the exponents are fractal dimensions, which are obtained numerically for the first time. Our results are consistent with the Coulomb gas predictions for the critical O(n) branch for n 〈 2 and the results obtained by previous transfer matrix calculations. For n = 2, we find that the thermal exponent, the magnetic exponent and the fractal dimension of the largest critical Eulerian bond component are different from those of the critical 0(2) loop model. These results confirm that the cubic anisotropy is marginal at n = 2 but irrelevant for n〈2. 展开更多
关键词 phase transition and critical phenomena Eulerian-bond cubic model Monte Carlo sim-ulation fractal dimension
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Subspace Minimization Conjugate Gradient Method Based on Cubic Regularization Model for Unconstrained Optimization 被引量:1
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作者 Ting Zhao Hongwei Liu 《Journal of Harbin Institute of Technology(New Series)》 CAS 2021年第5期61-69,共9页
Many methods have been put forward to solve unconstrained optimization problems,among which conjugate gradient method(CG)is very important.With the increasing emergence of large⁃scale problems,the subspace technology ... Many methods have been put forward to solve unconstrained optimization problems,among which conjugate gradient method(CG)is very important.With the increasing emergence of large⁃scale problems,the subspace technology has become particularly important and widely used in the field of optimization.In this study,a new CG method was put forward,which combined subspace technology and a cubic regularization model.Besides,a special scaled norm in a cubic regularization model was analyzed.Under certain conditions,some significant characteristics of the search direction were given and the convergence of the algorithm was built.Numerical comparisons show that for the 145 test functions under the CUTEr library,the proposed method is better than two classical CG methods and two new subspaces conjugate gradient methods. 展开更多
关键词 cubic regularization model conjugate gradient method subspace technique unconstrained optimization
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Estimation of the water–oil–gas relative permeability curve from immiscible WAG coreflood experiments using the cubic B-spline model
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作者 Dai-Gang Wang Yong-Le Hu +1 位作者 Jing-Jing Sun Yong Li 《Petroleum Science》 SCIE CAS CSCD 2016年第3期507-516,共10页
Immiscible water-alternating-gas(WAG) flooding is an EOR technique that has proven successful for water drive reservoirs due to its ability to improve displacement and sweep efficiency.Nevertheless,considering the c... Immiscible water-alternating-gas(WAG) flooding is an EOR technique that has proven successful for water drive reservoirs due to its ability to improve displacement and sweep efficiency.Nevertheless,considering the complicated phase behavior and various multiphase flow characteristics,gas tends to break through early in production wells in heterogeneous formations because of overriding,fingering,and channeling,which may result in unfavorable recovery performance.On the basis of phase behavior studies,minimum miscibility pressure measurements,and immiscible WAG coreflood experiments,the cubic B-spline model(CBM) was employed to describe the three-phase relative permeability curve.Using the Levenberg-Marquardt algorithm to adjust the vector of unknown model parameters of the CBM sequentially,optimization of production performance including pressure drop,water cut,and the cumulative gas-oil ratio was performed.A novel numerical inversion method was established for estimation of the water-oil-gas relative permeability curve during the immiscible WAG process.Based on the quantitative characterization of major recovery mechanisms,the proposed method was validated by interpreting coreflood data of the immiscible WAG experiment.The proposed method is reliable and can meet engineering requirements.It provides a basic calculation theory for implicit estimation of oil-water-gas relative permeability curve. 展开更多
关键词 cubic B-spline model Immiscible WAG flooding Relative permeability Numerical inversion
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MODELING OF 3-D IMAGES AND SPACE MARKOV CUBIC MESH MODELS
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作者 钱唯 《Journal of Electronics(China)》 1990年第3期280-284,共5页
Three-dimensional(3-D)Markov cubic random mesh models are presented andproved in the form of two theorems in details.Its applications to the modeling and description of3-D images are described.The model presented here... Three-dimensional(3-D)Markov cubic random mesh models are presented andproved in the form of two theorems in details.Its applications to the modeling and description of3-D images are described.The model presented here is a appropriate mathematical tool for thesegmentation,modeling,classification and other processing.Finally,an example is given. 展开更多
关键词 MARKOV cubic MESH model modeling 3-D IMAGE
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Enhancing asphaltene precipitation modeling by cubic-PR solid model using thermodynamic correlations and averaging techniques 被引量:1
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作者 Aktham E.Shoukry Ahmed H.El-Banbi Helmy Sayyouh 《Petroleum Science》 SCIE CAS CSCD 2020年第1期232-241,共10页
Cubic equation-of-state solid models are one of the most widely used models to predict asphaltene precipitation behavior.Thermodynamic parameters are needed to model precipitation under different pressures and tempera... Cubic equation-of-state solid models are one of the most widely used models to predict asphaltene precipitation behavior.Thermodynamic parameters are needed to model precipitation under different pressures and temperatures and are usually obtained through tuning with multi asphaltene onset experiments.For the purpose of enhancing the cubic Peng–Robinson solid model and reducing its dependency on asphaltene experiments,this paper tests the use of aromatics and waxes correlations to obtain these thermodynamic parameters.In addition,weighted averages between both correlations are introduced.The averaging is based on reported saturates,aromatics,resins,asphaltene(SARA)fractions,and wax content.All the methods are tested on four oil samples,with previously published data,covering precipitation and onset experiments.The proposed wax-asphaltene average showed the best match with experimental data,followed by a SARA-weighted average.This new addition enhances the model predictability and agrees with the general molecular structure of asphaltene molecules. 展开更多
关键词 ASPHALTENE PRECIPITATION ASPHALTENE ONSET pressure ASPHALTENE PRECIPITATION modelING ASPHALTENE THERMODYNAMICS cubic equation of state
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CYCLIC DEFORMATION OF FACE CENTERED CUBIC CRYSTALS AND ITS DISLOCATION INTERACTION MODEL——Ⅱ.DISLOCATION INTERACTION MODEL OF CYCLIC DEFORMATION
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作者 JIN Nengyun Shanghai Jiaotong University Jin Nengyun,Department of Materials Science,Shanghai Jiaotong University,Shanghai 200030,China.Present address:Max-Planck-Institut für Metallforschung,Institut für Physik,7000 Stuttgart 80,FRG 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1989年第2期93-99,共7页
A dislocation interaction model has been proposed for cyclic deformation of fcc crystals.Ac- cording to this model,cyclic stress-strain responses and saturation dislocation structures of a crystal are associated with ... A dislocation interaction model has been proposed for cyclic deformation of fcc crystals.Ac- cording to this model,cyclic stress-strain responses and saturation dislocation structures of a crystal are associated with the modes and intensities of dislocation interactions between slip systems active in the crystal; and,hence,may be predicted by the location of its tensile axis in the crystallographic triangle.This model has successfully explained the different behaviours of double-slip crystals and multi-slip behaviours of some crystals with orientations usually con- sidered as single-slip ones. 展开更多
关键词 face centered cubic crystal dislocation interaction model multi-slip cyclic deformation
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A Finite Element Cable Model and Its Applications Based on the Cubic Spline Curve 被引量:2
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作者 方子帆 贺青松 +3 位作者 向兵飞 肖化攀 何孔德 杜义贤 《China Ocean Engineering》 SCIE EI CSCD 2013年第5期683-692,共10页
For accurate prediction of the deformation of cable in the towed system, a new finite element model is presented that provides a representation of both the bending and torsional effects. In this paper, the cubic splin... For accurate prediction of the deformation of cable in the towed system, a new finite element model is presented that provides a representation of both the bending and torsional effects. In this paper, the cubic spline interpolation function is applied as the trial solution. By using a weighted residual approach, the discretized motion equations for the new finite element model are developed. The model is calculated with the computation program complier by Matlab. Several numerical examples are presented to illustrate the numerical schemes. The results of numerical simulation are stable and valid, and consistent with the mechanical properties of the cable. The model can be applied to kinematics analysis and the design of ocean cable, such as mooring lines, towing, and ROV umbilical cables. 展开更多
关键词 tension stiffness bending stiffness torsion stiffness cubic spline curve Galerkin criterion finite element model
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AN INTEGRATION METHOD WITH FITTING CUBIC SPLINE FUNCTIONS TO A NUMERICAL MODEL OF 2ND-ORDER SPACE-TIME DIFFERENTIAL REMAINDER——FOR AN IDEAL GLOBAL SIMULATION CASE WITH PRIMITIVE ATMOSPHERIC EQUATIONS
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作者 辜旭赞 张兵 王明欢 《Journal of Tropical Meteorology》 SCIE 2013年第4期388-396,共9页
In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubi... In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubic spline numerical model(Spline Model for short),which is with a quasi-Lagrangian time-split integration scheme of fitting cubic spline/bicubic surface to all physical variable fields in the atmospheric equations on spherical discrete latitude-longitude mesh.A new algorithm of"fitting cubic spline—time step integration—fitting cubic spline—……"is developed to determine their first-and2nd-order derivatives and their upstream points for time discrete integral to the governing equations in Spline Model.And the cubic spline function and its mathematical polarities are also discussed to understand the Spline Model’s mathematical foundation of numerical analysis.It is pointed out that the Spline Model has mathematical laws of"convergence"of the cubic spline functions contracting to the original functions as well as its 1st-order and 2nd-order derivatives.The"optimality"of the 2nd-order derivative of the cubic spline functions is optimal approximation to that of the original functions.In addition,a Hermite bicubic patch is equivalent to operate on a grid for a 2nd-order derivative variable field.Besides,the slopes and curvatures of a central difference are identified respectively,with a smoothing coefficient of 1/3,three-point smoothing of that of a cubic spline.Then the slopes and curvatures of a central difference are calculated from the smoothing coefficient 1/3 and three-point smoothing of that of a cubic spline,respectively.Furthermore,a global simulation case of adiabatic,non-frictional and"incompressible"model atmosphere is shown with the quasi-Lagrangian time integration by using a global Spline Model,whose initial condition comes from the NCEP reanalysis data,along with quasi-uniform latitude-longitude grids and the so-called"shallow atmosphere"Navier-Stokes primitive equations in the spherical coordinates.The Spline Model,which adopted the Navier-Stokes primitive equations and quasi-Lagrangian time-split integration scheme,provides an initial ideal case of global atmospheric circulation.In addition,considering the essentially non-linear atmospheric motions,the Spline Model could judge reasonably well simple points of any smoothed variable field according to its fitting spline curvatures that must conform to its physical interpretation. 展开更多
关键词 NUMERICAL forecast and NUMERICAL SIMULATION 2nd-order SPACE-TIME differential REMAINDER NUMERICAL model cubic spline functions Navier-Stokes PRIMITIVE EQUATIONS quasi-Lagrangian time-split integration scheme global SIMULATION case
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Constructing B-rep Solid Model from Cubic Volume Cells
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作者 Liu Jinyi Fu Guangri(Dept of Computer Science & Technology, Fushun Petroleum Institute, Fushun, 113001)Maekawa Electric Steel Casting Co., Fukuoka, 800-03, Japan) 《Computer Aided Drafting,Design and Manufacturing》 1999年第1期30-38,共9页
The paper introduces a method for displaying cubic volume cells (voxels) resulting frompartitioning given objectS with orthogonal planes for finite difference calculation. The method representS ablock of voxels as a B... The paper introduces a method for displaying cubic volume cells (voxels) resulting frompartitioning given objectS with orthogonal planes for finite difference calculation. The method representS ablock of voxels as a B-rep solid model and conStrUcts the B-rep geometric clementS with an approach frombottom to up. Once the B-rep model is established, it is efficient in displaying because inner voxels areomitted and many coplanar facetS are merged together. By displaying the interSeCtion lines of theconstructed B-reP model and the partitioning planes, the tessellation image can be generated. 展开更多
关键词 finite difference method cubic volume cell B-rep solid model.
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使用鱼眼镜头制作QuickTime CubicVR 被引量:3
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作者 张燕翔 吴敏 邵敏勇 《系统仿真学报》 CAS CSCD 2001年第S2期568-569,共2页
讨论了最新的QuickTime CubicVR技术的几种合成方法,并就其中最简单易行的鱼眼镜头法进行了深入的探讨,得到了这种方法的数学模型,为以后的软件开发奠定了基础。
关键词 鱼眼镜头 QuickTimecubicVR 数学模型
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严重肾病患者血浆脂蛋白(a)与急性心肌梗死风险的关系:一项基于限制性立方样条模型分析的研究
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作者 郭丽娟 袁玉婷 +3 位作者 孙星河 张贤 杨泉 刘小慧 《中国心血管病研究》 2026年第2期121-126,共6页
目的探讨严重肾脏病[估算肾小球滤过率(eGFR)<30 ml·min-1·1.73m-2]患者血浆脂蛋白a[Lp(a)]水平与急性心肌梗死(AMI)风险的关系,评价血浆Lp(a)水平对AMI风险的预测价值。方法选取2018年7月至2023年3月北京大学国际医院心... 目的探讨严重肾脏病[估算肾小球滤过率(eGFR)<30 ml·min-1·1.73m-2]患者血浆脂蛋白a[Lp(a)]水平与急性心肌梗死(AMI)风险的关系,评价血浆Lp(a)水平对AMI风险的预测价值。方法选取2018年7月至2023年3月北京大学国际医院心血管内科就诊的伴严重肾脏病的冠心病患者136例,其中确诊AMI的43例患者作为研究组(AMI组),非AMI的93例患者作为对照组(非AMI组)。血浆Lp(a)>300mg/L定义为高Lp(a)。分别以高Lp(a)以及血浆Lp(a)水平四分组作为自变量,基于Logistic回归分析模型绘制限制性立方样条(RCS)曲线,分析Lp(a)与AMI风险的关系。进一步绘制血浆Lp(a)水平单一指标预测AMI的受试者工作特征曲线(ROC)。基于约登指数计算血浆Lp(a)预测严重肾脏病患者发生AMI的最佳截断值、敏感度和特异度。结果严重肾脏病患者中,CKD4期与CKD5期患者的血浆Lp(a)水平无显著差异(P>0.05)。AMI组患者的高Lp(a)比例显著高于非AMI组[275.0(132.0,778.0)mg/L比103.0(58.0,196.0)mg/L,P<0.05]。多因素Logistic回归分析及趋势性检验结果显示,校正混杂因素后,高Lp(a)(OR=3.95,95%CI 1.59~9.83,P<0.01)是影响严重肾脏病患者发生AMI的独立预测因素,其中,Lp(a)最高四分位数组(Q4)发生AMI的风险为最低四分位数组(Q1)的6.36倍。Lp(a)与AMI风险之间存在线性剂量-反应关系(P非线性>0.05)。ROC曲线结果显示,血浆Lp(a)水平预测AMI的AUC值为0.713(95%CI 0.615~0.810,P<0.01),最佳截断值为145 mg/L时,敏感度为0.744,特异度为0.624。结论在严重肾脏病患者中,血浆Lp(a)水平升高显著增加AMI的风险,二者之间存在的线性剂量-反应关系,血浆Lp(a)水平升高可作为严重肾脏病患者AMI风险的预测因子。 展开更多
关键词 急性心肌梗死 血浆脂蛋白(a) 严重肾脏病 限制性立方样条模型
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血清B型利尿钠肽及微RNA-132与慢性阻塞性肺疾病急性加重期患者并发心力衰竭的剂量-反应关系
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作者 王银娟 付英 昌敏 《中国医刊》 2026年第2期146-150,共5页
目的探讨血清B型利尿钠肽(BNP)、微RNA-132(miR-132)与慢性阻塞性肺疾病急性加重期(AECOPD)患者并发心力衰竭的剂量-反应关系。方法选取2021年1月至2024年12月山西医科大学附属运城市中心医院收治的205例AECOPD患者,根据住院期间是否并... 目的探讨血清B型利尿钠肽(BNP)、微RNA-132(miR-132)与慢性阻塞性肺疾病急性加重期(AECOPD)患者并发心力衰竭的剂量-反应关系。方法选取2021年1月至2024年12月山西医科大学附属运城市中心医院收治的205例AECOPD患者,根据住院期间是否并发心力衰竭分为发生组和未发生组。应用倾向评分匹配两组基线协变量,匹配后两组分别纳入70例患者。比较匹配后两组患者的血清BNP、miR-132水平,应用logistic回归方程和限制性立方样条模型(RCS)分析血清BNP、miR-132水平与AECOPD患者并发心力衰竭的相关性,应用受试者操作特征(ROC)曲线分析血清BNP、miR-132水平对AECOPD患者并发心力衰竭的预测效能。结果发生组第一秒用力呼气容积占预计值百分比(FEV_(1)%)、第一秒用力呼气容积占用力肺活量百分比(FEV_(1)/FVC)及miR-132水平低于未发生组,急性生理与慢性健康状况评价Ⅱ(APACHEⅡ)评分、BNP水平高于未发生组,差异有统计学意义(P<0.05);校正FEV_(1)%、FEV_(1)/FVC、APACHEⅡ评分后,BNP、miR-132仍是AECOPD患者并发心力衰竭的影响因素(P<0.05);心力衰竭与BNP呈线性相关,与miR-132呈非线性相关(P<0.05);BNP联合miR-132对AECOPD患者并发心力衰竭的预测效能高于FEV_(1)%、FEV_(1)/FVC及APACHEⅡ评分联合应用(AUC分别为0.926、0.849;P<0.05)。结论血清BNP、miR-132与AECOPD患者并发心力衰竭密切相关,联合检测可提高对心力衰竭的预测效能,有助于临床识别高危人群,采取合理诊治措施。 展开更多
关键词 慢性阻塞性肺疾病急性加重期 心力衰竭 B型利尿钠肽 微RNA-132 限制性立方样条模型
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基于复合插值算法的硅基压力传感器补偿研究
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作者 朱建亭 樊磊 +1 位作者 亓雪 谭秋林 《传感器与微系统》 北大核心 2026年第3期19-24,共6页
针对硅基压阻式压力传感器的温度漂移严重制约多通道压力采集系统测量精度的问题,提出了一种基于拉格朗日插值与三次样条插值结合的补偿算法。算法在离线阶段采用分段策略的拉格朗日插值构建温度—电压映射模型,并利用三次样条插值构建... 针对硅基压阻式压力传感器的温度漂移严重制约多通道压力采集系统测量精度的问题,提出了一种基于拉格朗日插值与三次样条插值结合的补偿算法。算法在离线阶段采用分段策略的拉格朗日插值构建温度—电压映射模型,并利用三次样条插值构建电压—压力的非线性映射模型,实时阶段通过查询预建模型快速定位压力区间,并计算补偿值。为验证算法有效性,设计了一种多通道压力测试系统,在30~80℃的温度范围内进行传标定和补偿验证。实验结果表明,补偿后传感器在全温度范围内的非线性误差降低至0.034 4%FS以下,准确度达到0.103 9%FS,与使用多项式拟合和反向传播(BP)神经网络的方法相比,所提算法在提升补偿精度的同时,具备较高的计算效率。 展开更多
关键词 硅基压力传感器 离线建模 拉格朗日插值 三次样条插值
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运用Cubic曲线模型预测深圳市售乳制品铅含量及人群暴露水平评估
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作者 王舟 黄薇 +1 位作者 潘柳波 谭唯 《中国公共卫生管理》 2011年第6期569-570,共2页
目的建立未来3年深圳市售乳制品中铅含量的预测数学模型,评估人群暴露水平,以了解其可能风险。方法根据2001~2010年深圳市乳制品中铅检测数据,应用Cubic曲线模型对未来3年深圳市售乳制品中铅含量进行预测,并结合深圳市膳食调查人群乳... 目的建立未来3年深圳市售乳制品中铅含量的预测数学模型,评估人群暴露水平,以了解其可能风险。方法根据2001~2010年深圳市乳制品中铅检测数据,应用Cubic曲线模型对未来3年深圳市售乳制品中铅含量进行预测,并结合深圳市膳食调查人群乳制品消费量数据,评估人群的暴露水平。结果 Cubic曲线模型结果显示2011-2013年深圳市乳制品铅含量有上升降趋势,为0.087~0.246mg/kg;人群乳制品铅暴露量也呈上升趋势,为9.962~28.167μg/d/p,占PTDI的4.648%~13.144%。结论目前深圳市居民通过乳制品摄入铅的风险尚较小。 展开更多
关键词 污染趋势 cubic曲线模型 人群暴露水平
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基于限制性立方样条模型分析轻度急性缺血性脑卒中病人衰弱、体质指数与肌少症的关联性
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作者 叶俊华 陈蕊 +3 位作者 刘竹韵 胡采霞 叶日春 魏琳 《循证护理》 2026年第4期777-782,共6页
目的:探讨轻度急性缺血性脑卒中病人衰弱、体质指数(BMI)与肌少症的相关性。方法:采用便利抽样法选取2020年7月—2021年5月广州中医药大学第二附属医院招募的首次轻度急性缺血性脑卒中住院病人118例作为研究对象,收集一般资料、实验室... 目的:探讨轻度急性缺血性脑卒中病人衰弱、体质指数(BMI)与肌少症的相关性。方法:采用便利抽样法选取2020年7月—2021年5月广州中医药大学第二附属医院招募的首次轻度急性缺血性脑卒中住院病人118例作为研究对象,收集一般资料、实验室检查、衰弱、肌少症、BMI等信息。采用单因素和多因素Logistic回归分析衰弱和BMI与肌少症发生风险之间的关联,采用受试者工作特征(ROC)曲线确定衰弱和BMI对肌少症的预测价值。使用限制性立方样条(RCS)模型进一步阐明轻度急性缺血性脑卒中病人BMI与肌少症间的剂量-反应关系。结果:118例轻度急性缺血性脑卒中病人肌少症患病率为39.8%。Logistic回归分析结果显示,衰弱前期、衰弱、BMI是轻度急性缺血性脑卒中病人肌少症发生的影响因素(P<0.05)。多因素Logistic回归模型在校正潜在混杂因素后,上述关联关系保持稳定。ROC曲线显示,衰弱和BMI的ROC曲线下面积分别为0.65[95%CI(0.55,0.75)]和0.86[95%CI(0.80,0.93)]。限制性立方样条分析结果显示,轻度急性缺血性脑卒中病人BMI与肌少症之间存在剂量-反应关系。当BMI<23.1 kg/m^(2)时,肌少症发生风险随BMI降低而明显升高;而当BMI>23.1 kg/m^(2)时,肌少症发生风险趋于平稳。结论:衰弱、BMI可作为轻度急性缺血性脑卒中病人肌少症发生的重要预测指标,BMI对肌少症发生风险具有明显的剂量-反应特征。 展开更多
关键词 脑卒中 肌少症 体质指数 衰弱 限制性立方样条模型 护理
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某院药品消耗指数与DRG超支的相关性及阈值效应分析 被引量:4
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作者 杨香瑜 李璐璐 +1 位作者 余子珩 张韶辉 《中国药房》 北大核心 2025年第1期113-116,共4页
目的探讨药品消耗指数与疾病诊断相关分组(DRG)超支的相关性,为医院优化费用结构、加强精细化管理提供依据。方法以某三级甲等医院2023年9-11月DRG入组病例为研究资料,分别采用Logistic回归模型、限制性立方样条(RCS)模型分析药品消耗... 目的探讨药品消耗指数与疾病诊断相关分组(DRG)超支的相关性,为医院优化费用结构、加强精细化管理提供依据。方法以某三级甲等医院2023年9-11月DRG入组病例为研究资料,分别采用Logistic回归模型、限制性立方样条(RCS)模型分析药品消耗指数与DRG超支的相关性以及阈值效应。同时基于药品消耗指数开展合理用药点评,进行精准控费及管理,并分析管控前(2023年1-6月)与管控后(2024年1-6月)全院主要药事指标变化情况。结果多因素Logistic回归分析结果显示,住院天数长、药品消耗指数高、转科、合并糖尿病是DRG超支的危险因素(P<0.05)。RCS模型结果表明,药品消耗指数与DRG超支呈非线性关系,当药品消耗指数≥0.64时,药品消耗指数与DRG超支风险呈正相关(P<0.05)。与管控前同期比较,管控后的次均医疗费用、次均药品费用、药品消耗指数均显著下降(P<0.01)。结论药品消耗指数是DRG超支的危险因素,其与DRG超支存在非线性关系和阈值效应。各医院可结合实际药品使用情况、疾病谱特征以及成本控制目标,综合考虑医疗质量、患者需求和医保支付能力等因素,设定合理的阈值并实施动态监测与干预,以实现药品使用的精准管控。 展开更多
关键词 药品消耗指数 疾病诊断相关分组 LOGISTIC回归 限制性立方样条模型 阈值效应
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Effective Stacking Fault Energy in Face-Centered Cubic Metals 被引量:1
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作者 Ke-Qiang Li Zhen-Jun Zhang +3 位作者 Lin-Lin Li Peng Zhang Jin-Bo Yang Zhe-Feng Zhang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2018年第8期873-877,共5页
As a typical configuration in plastic deformations, dislocation arrays possess a large variation of the separation of the partial dislocation pairs in face-centered cubic(fcc) metals. This can be manifested convenie... As a typical configuration in plastic deformations, dislocation arrays possess a large variation of the separation of the partial dislocation pairs in face-centered cubic(fcc) metals. This can be manifested conveniently by an effective stacking fault energy(SFE). The effective SFE of dislocation arrays is described within the elastic theory of dislocations and verified by atomistic simulations. The atomistic modeling results reveal that the general formulae of the effective SFE can give a reasonably satisfactory prediction for all dislocation types, especially for edge dislocation arrays. Furthermore, the predicted variation of the effective SFE is consistent with several previous experiments, in which the measured SFE is not definite, changing with dislocation density. Our approach could provide better understandings of cross-slip and the competition between slip and twinning during plastic deformations in fcc metals. 展开更多
关键词 Face-centered cubic Stacking fault energy - Dislocation dissociation Atomistic modeling
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A comparison of piecewise cubic Hermite interpolating polynomials,cubic splines and piecewise linear functions for the approximation of projectile aerodynamics 被引量:6
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作者 C.A.Rabbath D.Corriveau 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第5期741-757,共17页
Modelling and simulation of projectile flight is at the core of ballistic computer software and is essential to the study of performance of rifles and projectiles in various engagement conditions.An effective and repr... Modelling and simulation of projectile flight is at the core of ballistic computer software and is essential to the study of performance of rifles and projectiles in various engagement conditions.An effective and representative numerical model of projectile flight requires a relatively good approximation of the aerodynamics.The aerodynamic coefficients of the projectile model should be described as a series of piecewise polynomial functions of the Mach number that ideally meet the following conditions:they are continuous,differentiable at least once,and have a relatively low degree.The paper provides the steps needed to generate such piecewise polynomial functions using readily available tools,and then compares Piecewise Cubic Hermite Interpolating Polynomial(PCHIP),cubic splines,and piecewise linear functions,and their variant,as potential curve fitting methods to approximate the aerodynamics of a generic small arms projectile.A key contribution of the paper is the application of PCHIP to the approximation of projectile aerodynamics,and its evaluation against a set of criteria.Finally,the paper provides a baseline assessment of the impact of the polynomial functions on flight trajectory predictions obtained with 6-degree-of-freedom simulations of a generic projectile. 展开更多
关键词 Aerodynamic coefficients PIECEWISE POLYNOMIAL FUNCTIONS cubic splines Curve fitting PIECEWISE linear FUNCTIONS PIECEWISE cubic HERMITE interpolating POLYNOMIAL PROJECTILE modelling and simulation Fire control inputs Precision Ballistic computer software
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New insight into prediction of phase behavior of natural gas hydrate by different cubic equations of state coupled with various mixing rules
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作者 Amir Hossein Saeedi Dehaghani 《Petroleum Science》 SCIE CAS CSCD 2017年第4期780-790,共11页
Progress in hydrate thermodynamic study necessitates robust and fast models to be incorporated in reservoir simulation softwares. However, numerous models presented in the literature makes selection of the best,proper... Progress in hydrate thermodynamic study necessitates robust and fast models to be incorporated in reservoir simulation softwares. However, numerous models presented in the literature makes selection of the best,proper predictive model a cumbersome task. It is of industrial interest to make use of cubic equations of state(EOS) for modeling hydrate equilibria. In this regard, this study focuses on evaluation of three common EOSs including Peng–Robinson, Soave–Redlich–Kwong and Valderrama–Patel–Teja coupled with van der Waals and Platteeuw theory to predict hydrate P–T equilibrium of a real natural gas sample. Each EOS was accompanied with three mixing rules, including van der Waals(vd W),Avlonitis non-density dependent(ANDD) and general nonquadratic(GNQ). The prediction of cubic EOSs was in sufficient agreement with experimental data and with overall AARD% of less than unity. In addition, PR plus ANDD proved to be the most accurate model in this study for prediction of hydrate equilibria with AARD% of 0.166.It was observed that the accuracy of cubic EOSs studied in this paper depends on mixing rule coupled with them,especially at high-pressure conditions. Lastly, the present study does not include any adjustable parameter to be correlated with hydrate phase equilibrium data. 展开更多
关键词 Gas Hydrate cubic equation of state Mixing rule Thermodynamic modeling
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混合模式下医学生学习沉浸体验对系统思维的影响
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作者 林志萍 林淑娟 +1 位作者 郑建盛 颜桑桑 《沈阳医学院学报》 2025年第4期424-428,448,共6页
目的:探讨混合教学模式下医学生学习沉浸体验对其系统思维的影响。方法:选取2022至2023学年完成医学统计学课程学习的医学生为研究对象,采用SATS 36量表、青少年学习沉浸体验问卷、系统思考量表调查医学生的学习态度、学习沉浸体验和系... 目的:探讨混合教学模式下医学生学习沉浸体验对其系统思维的影响。方法:选取2022至2023学年完成医学统计学课程学习的医学生为研究对象,采用SATS 36量表、青少年学习沉浸体验问卷、系统思考量表调查医学生的学习态度、学习沉浸体验和系统思维。采用线性相关分析学习态度、学习沉浸体验与系统思维之间的相关关系;采用多重线性回归和限制性立方样条(Restricted cubic spline,RCS)模型分析控制性别、专业和学习态度影响后,学习沉浸体验与系统思维之间的线性和非线性关系。结果:349名医学生的学习态度均分为(4.31±0.59)分,学习沉浸体验均分为(3.33±0.65)分,均处于中等偏上水平;系统思维得分为(59.01±13.57)分,处于中等水平。医学生的学习沉浸体验、学习态度和系统思维间均呈正相关。学习沉浸体验存在性别和专业差异。在控制了性别、专业和学习态度影响后,多重线性回归结果显示,学习沉浸体验和系统思维存在线性趋势关系(P<0.01);RCS模型分析显示,学习沉浸体验和系统思维之间存在J型的非线性关系(P for non-linearity<0.01);以中位数3.16为拐点,学习沉浸体验得分<3.16分时,对医学生的系统思维不产生影响(P=0.51);当得分≥3.16分时,随着学习沉浸体验增加,医学生的系统思维随之增加(Beta per SD=0.56,95%CI:0.44~0.68,P<0.01)。结论:混合模式下医学生的学习沉浸体验会对系统思维产生促进作用,当学习沉浸体验得分≥3.16分时,医学生的学习沉浸体验越高,系统思维随之增加。不同维度学习沉浸体验与系统思维的密切程度不一样。 展开更多
关键词 医学统计学 混合教学 学习态度 学习沉浸体验 系统思维 趋势分析 限制性立方样条模型
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