基于R-L分数阶定义的CCM Flyback变换器建模与分析

针对电容电感都为分数阶这一事实,利用分数阶微积分R-L定义和状态空间平均法,对工作在电感电流连续模式(CCM)下的分数阶Flyback变换器进行建模与分析。推导CCM分数阶Flyback变换器的静态工作点和小信号传递函数以及变换器工作在CCM模式下的条件。其次,讨论Caputo模型与R-L导数模型的区别,得出在R-L分数阶定义下直流静态工作点不仅与占空比相关,而且还与电感和电容的阶数以及负载有关。最后,在PSIM中搭建R-L分数阶CCM Flyback变换器电路模型,得到不同分数阶电感电容阶数下分数阶Flyback变换器输出电压和电感电流的仿真波形,通过仿真结果与理论计算结果对比,验证所建模型的正确性,得出分数阶电感电容的阶数会影响闭环控制器的设计和分数阶模型能更加精确地描述Flyback变换器的工作特性。

盐湖大气环境下316 L仪表管点蚀深度预测研究

为提高316 L仪表管在盐湖大气环境下点蚀深度的预测精度,采用变阶平均弱化缓冲算子、积分背景值和新陈代谢对分数阶累加灰色模型FGM(1,1,r)进行改进,首先通过改进Tent混沌映射、莱维飞行和区间自适应反向学习策略提高黏菌算法(SMA)的寻优能力和收敛速度,随后利用改进黏菌算法(ISMA)对FGM(1,1,r,ρ)中的参数r和ρ进行寻优,最后构建仪表管ISMA-FGM(1,1,r,ρ)点蚀深度预测模型。研究结果表明:经优化的新模型比原模型误差更小、拟合度更高,在仪表管点蚀深度预测方面具有更好的性能。研究结果可为仪表管道系统的完整性评价和风险预警提供参考。

Biomass-Based Rice (Oryza sativa L.) Aboveground Architectural Parameter Models

To quantify the relationships between rice plant architecture parameters and the corresponding organ biomass, and to research on functional structural plant models of rice plant, this paper presented a biomass-based model of aboveground architectural parameters of rice （Oryza sativa L.） in the young seedling stage, designed to explain effects of cultivars and environmental conditions on rice aboveground morphogenesis at the individual leaf level. Various model variables, including biomass of blade and blade length, were parameterized for rice based on data derived from an outdoor experiment with rice cv. Liangyou 108, 86You 8, Nanjing 43, and Yangdao 6. The organ dimensions of rice aboveground were modelled taking corresponding organ biomass as an independent variable. Various variables in rice showed marked consistency in observation and simulation, suggesting possibilities for a general rice architectural model in the young seedling stage. Our descriptive model was suitable for our objective. However, they can set the stage for connection to physiological model via biomass and development of functional structural rice models （FSRM）, and start with the localized production and partitioning of assimilates as affected by abiotic growth factors. The finding of biomass-based rice architectural parameter models also can be used in morphological models of blade, sheath, and tiller of the other stages in rice life.

Modelling the impacts of cover crop management strategies on the water use,carbon exchange and yield of olive orchards

Cover crops have long been proposed as an alternative soil management for minimizing erosion rates in olive stands while providing additional ecosystem services.However,the trade-off between these benefits and the competition for water with the trees makes the definition of optimal management practices a challenging task in semiarid climates.This work presents an improved version of OliveCan,a process-based simulation model of olive orchards that now can simulate the main impacts of cover crops on the water and carbon balances of olive orchards.Albeit simple in its formulation,the new model components were developed to deal with different cover crop management strategies.Examples are presented for simulation runs of a traditional olive orchard in the conditions of southern Spain,evaluating the effects of different widths for the strip occupied by the cover crop(Fcc)and two contrasting mowing dates.Results revealed that high Fccresulted in lower olive yields,but only when mowing was applied at the end of spring.In this regard,late mowing and high Fccwas associated with lower soil water content from spring to summer,coinciding with olive flowering and the earlier stages of fruit growth.Fccwas also negatively correlated with surface runoff irrespective of the mowing date.On the other hand,net ecosystem productivity(NEP)was substantially affected by both Fccand mowing date.Further simulations under future climate scenarios comparing the same management alternatives are also presented,showing substantial yield reductions by the end of the century and minor or negligible changes in NEP and seasonal runoff.

GLOBAL SOLUTIONS TO A HYDRODYNAMIC MODEL FOR SEMICONDUCTORS WITH VELOCITY RELAXATION

In this paper,we apply the method given in the paper“Zero relaxation time limits to a hydrodynamic model of two carrier types for semiconductors”(Mathematische Annalen,2022,382:1031–1046)to study the Cauchy problem for a one dimensional inhomogeneous hydrodynamic model of two-carrier types for semiconductors with the velocity relaxation.

Genetic variation of height growth rhythm between clones of Larix kaempferi × L. gmelini based on logistic models

Fifty-three larch interspecific hybrid clones（Larix kaempferi × L.gmelini） and their parent clones were used for growth curve analysis of height variations.The growth curves of the 55 clones were ＇S＇-shaped and 36 exhibited similar curves as the male parent.The coefficients of the logistic models were higher than 0.943,indicating that our results were effective in the simulation of the growth curves.ANOVA analysis showed significant differences in height of different clones （P／0.01）.Average date of maximum height growth was Day 173,and average duration of rapid growth lasted for 50 days.Annual average increase in height was 9.7cm d^（-1） and daily average increase was 0.2 cm.The ratio of GR to the total annual increase in height ranged from 51.2 to 68.8%,with the average being 59.8%.There was a positive correlation between k values and plant heights which benefited from the evaluation of early plant height.There was also a positive correlation between GR（growth stage）,GD（plant height） and annual increase in height.These results are informative to the evaluation of the elite clone selection and provide a theoretical basis for breeding and management.

A Study on the Nonlinear Caputo-Type Snakebite Envenoming Model with Memory

In this article,we introduce a nonlinear Caputo-type snakebite envenoming model with memory.The well-known Caputo fractional derivative is used to generalize the previously presented integer-order model into a fractionalorder sense.The numerical solution of the model is derived from a novel implementation of a finite-difference predictor-corrector(L1-PC)scheme with error estimation and stability analysis.The proof of the existence and positivity of the solution is given by using the fixed point theory.From the necessary simulations,we justify that the first-time implementation of the proposedmethod on an epidemicmodel shows that the scheme is fully suitable and time-efficient for solving epidemic models.This work aims to show the novel application of the given scheme as well as to check how the proposed snakebite envenoming model behaves in the presence of the Caputo fractional derivative,including memory effects.

Adjustment of Mathematical Models and the Quality of Drying the Pulped Coffee at Different Air Conditions

The aim of the study was to describe the drying kinetics of washed coffee (Coffea arabica L.) and evaluate the best mathematical model to fit the experimental drying data conducted with different air humidity (40%, 50% and 60%), temperatures (23, 40 and 60 °C) and the quality of the coffee. The cherries coffee were separated and standardized in the processes of washing, mechanical and manual separation. Then, approx. 85 kg of coffee cherries were pulped and taken directly to the yard. The washed coffee was completed dried in a mechanical dryer and yard. The results showed that the different conditions of the ambient air significantly influenced the processes of drying. The water content of the hygroscopic equilibrium of pulped coffee is directly proportional to the water activity and relative humidity (RH), decreasing with increasing temperature, for the same value of equilibrium. The Oswin model was best represented by the hygroscopicity of the pulped coffee, while the Midilli model shows the best fit to describe the drying curves of the washed coffee. The effective diffusion coefficient increases with increasing temperature of the drying air and reducing of RH, being described by the Arrhenius equation. Electrical conductivity, potassium leaching, total titratable acidity and grease acidity increase with increasing drying temperature regardless of the type of processing. Reducing sugars, total sugars and the sensorial quality was negatively affected with increasing drying temperature regardless of the type of processing. The drying at 60 °C/40% RH negatively affected the coffee quality.

基于自由曲面和L-system的红掌生长模型

针对红掌花卉生长可视化中参数难以确定的问题进行研究,提出推导控制点的方法,建立红掌器官模型:采用Bezier曲线结合扫描成型的方法来构造叶柄模型,采用双三次NURBS曲线对佛焰苞进行建模;运用红掌的相关表型数据拟合生长函数,提出基于红掌生长规律的微分L-system,可有效模拟红掌的拓扑结构和生长过程;通过虚拟器官表示红掌器官的几何属性,降低微分L-system的复杂度。试验验证提出的方法对红掌各项生长指标拟合度可达0.89以上,并可对每个生长阶段的红掌进行模拟,能有效地对红掌的生长过程进行建模。

Animal models of pulmonary hypertension due to left heart disease

Pulmonary hypertension due to left heart disease(PH-LHD) is regarded as the most prevalent form of pulmonary hypertension(PH). Indeed, PH is an independent risk factor and predicts adverse prognosis for patients with left heart disease(LHD). Clinically, there are no drugs or treatments that directly address PH-LHD, and treatment of LHD alone will not also ameliorate PH. To target the underlying physiopathological alterations of PH-LHD and to develop novel therapeutic approaches for this population, animal models that simulate the pathophysiology of PH-LHD are required. There are several available models for PH-LHD that have been successfully employed in rodents or large animals by artificially provoking an elevated pressure load on the left heart, which by transduction elicits an escalated pressure in pulmonary artery. In addition, metabolic derangement combined with aortic banding or vascular endothelial growth factor receptor antagonist is also currently applied to reproduce the phenotype of PH-LHD. As of today, none of the animal models exactly recapitulates the condition of patients with PH-LHD. Nevertheless, the selection of an appropriate animal model is essential in basic and translational studies of PH-LHD. Therefore, this review will summarize the characteristics of each PH-LHD animal model and discuss the advantages and limitations of the different models.

基于肠道菌群-LPS/TLR4通路探讨野菊花提取物对“过食膏粱厚味”致高尿酸血症大鼠的作用

[目的]研究野菊花提取物(Chrysanthemi Indici Flos extract,CYM.E)对“过食膏粱厚味”致高尿酸血症(hyperuricemia,HUA)大鼠的治疗作用及机制。[方法]将64只大鼠随机分为正常对照组,模型对照组,别嘌醇10 mg·kg^(-1)组,苯溴马隆5 mg·kg^(-1)组,CYM.E15、30、60、90 mg·kg^(-1)组,每组8只。除正常对照组外,其余各组均灌胃脂肪乳剂,建立拟人“过食膏粱厚味”致HUA大鼠模型。实验期间测定血清尿酸(uric acid,UA)、总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、高密度脂蛋白胆固醇(high density lipoprotein cholesterol,HDL-c)和低密度脂蛋白胆固醇(low density lipoprotein cholesterol,LDL-c)水平;酶联免疫吸附测定(enzyme linked immunosorbent assay,ELISA)法测定血清白细胞介素-6(interleukin-6,IL-6)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和血浆脂多糖(lipopolysaccharide,LPS)水平;实时荧光定量聚合酶链式反应(Real-time quantitative polymerase chain reaction,qRT-PCR)法测定小肠中TNF-α、Toll样受体4(Toll like receptor 4,TLR4)的mRNA表达;免疫印迹法检测小肠中TLR4蛋白表达;应用16S rDNA测序技术,对肠道菌群进行操作分类单元(operational taxonomic units,OTU)分类,选择合适的OTU进行结构分析、LEfSe差异贡献分析等。[结果]CYM.E能显著降低模型大鼠血清UA、TC、LDL-c、IL-6和TNF-α水平;显著降低血浆LPS水平;同时显著下调小肠组织TNF-αmRNA、TLR4 mRNA表达和TLR4蛋白表达,改善肠道的微炎症状态;增加乳酸杆菌、双歧杆菌的丰度与种类,降低拟杆菌、大肠杆菌的丰度与种类。[结论]CYM.E具有降低血清UA水平、调节血脂、减低炎症损伤、减少LPS释放等作用,可能通过调节肠道微生态发挥作用。

甲状腺全切+L-T_(4)皮下注射建立孕期亚临床甲减大鼠模型及稳定性研究

目的探讨采用甲状腺全切+L-T_(4)皮下注射方法建立孕期亚临床甲状腺功能减退症(SCH)大鼠模型及模型稳定性评价。方法选取26只体重180~200 g雌性SD大鼠作为研究对象,将其随机分为对照组(10只)及模型组(16只)。对照组采用甲状腺全切术,模型组采取甲状腺全切+术后L-T_(4)1.0μg/(100 g·d)皮下注射。观察2组大鼠术后1个月、甲状腺全切+术后L-T_(4)10 d后、妊娠13 d 3个时间点促甲状腺激素(TSH)、游离甲状腺素(TT4)水平和体重情况。结果模型组大鼠术后1个月血清TSH水平高于对照组,差异有统计学意义(P<0.01)。甲状腺全切+L-T_(4)10 d后,模型组大鼠血清TSH水平高于对照组,差异有统计学意义(P<0.01)。妊娠13 d时,模型组大鼠血清TSH水平明显高于对照组,差异有统计学意义(P<0.01)。模型组大鼠术后1个月血清TT4水平小于对照组,差异有统计学意义(P<0.01)。甲状腺全切+L-T_(4)10 d后2组大鼠血清TT4水平比较,差异无统计学意义(P>0.05)。妊娠13 d时,2组大鼠TT4水平比较,差异无统计学意义(P>0.05)。2组大鼠术前体重比较,差异无统计学意义(P>0.05)。术后1个月、甲状腺全切+L-T_(4)10 d后,模型组大鼠体重明显低于对照组,差异有统计学意义(P<0.01)。妊娠13 d时,模型组大鼠体重明显低于对照组,差异有统计学意义(P<0.01)。2组大鼠平均产子数比较,差异无统计学意义(P>0.05)。结论采用甲状腺全切+L-T_(4)皮下注射可以成功建立孕期SCH大鼠模型,且稳定性良好。

分级尾砂充填料浆L管实验及阻力特性研究

管道输送阻力是充填料浆管道输送的一个重要参数,目前普遍采用基于宾汉流变模型推导的白金汉公式进行计算,而管壁滑移效应的影响在该公式中被忽略,导致管道输送阻力的计算产生一定的偏差。因此本文基于L管输送实验,提出了考虑管壁滑移效应影响的充填料浆输送阻力计算方法,采用全面实验设计方案,研究了料浆质量分数、灰砂比和管壁滑移效应对于充填料浆管输阻力的影响。结果表明:管输阻力与质量分数、灰砂比呈正相关,与管壁滑移效应呈负相关。管壁滑移效应通过滑移贡献率来量化,该系数受质量分数的影响较明显,随着质量分数增大逐渐减弱,在质量分数较小时,受灰砂比的影响不明显。通过回归分析,构建了基于管径、流速、质量分数、灰砂比四变量,考虑管壁滑移效应的充填料浆管输阻力数学模型,并进行了工程实践验证。

L型抗滑桩加固土坡特性的离心模型试验与有限元模拟研究

L型抗滑桩在传统等截面抗滑桩的基础上加入横段,有效提高桩的稳定性和加固边坡效果。本文采用离心模型试验与数值模拟相结合的方法研究了L型抗滑桩加固土坡的变形特征与桩土相互作用。基于离心模型试验得到了L型抗滑桩加固土坡的位移场,并采用有限元软件对离心模型试验过程进行了数值模拟,数值与试验结果得出的土坡荷载位移曲线吻合程度较高,水平位移分布趋势基本一致。模拟结果表明,L型抗滑桩的加固效果明显优于传统等截面抗滑桩,土坡位移减小约25%,桩转角减小约70%。通过对比、融合离心模型试验观测与数值模拟结果,分析了L型抗滑桩对土坡的加固效果及桩-土相互作用。横段上下侧的土压力分布相差很大,差距最大时上侧土压力仅为下侧土压力的20%左右。L型抗滑桩横段与土的摩擦力分布存在极小值,竖直段抗滑桩可以改变土坡位移场,使得内侧位移分布存在极大值。坡体受力变形分析结果表明,抗滑桩导致土坡出现土拱效应,L型抗滑桩的横段会进一步增强土拱效应,形成应力重分布,使横段所受土压力增大,提高抗滑桩的稳定性。

Composition Analysis and Identification of Ancient Glass Products Based on L1 Regularization Logistic Regression

In view of the composition analysis and identification of ancient glass products, L1 regularization, K-Means cluster analysis, elbow rule and other methods were comprehensively used to build logical regression, cluster analysis, hyper-parameter test and other models, and SPSS, Python and other tools were used to obtain the classification rules of glass products under different fluxes, sub classification under different chemical compositions, hyper-parameter K value test and rationality analysis. Research can provide theoretical support for the protection and restoration of ancient glass relics.

Effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids by using the Lord-Shulman and dual-phase-lag models

The effects of rotation and gravity on an electro-magneto-thermoelastic medium with diffusion and voids in a generalized thermoplastic half-space are studied by using the Lord-Shulman (L-S) model and the dual-phase-lag (DPL) model. The analytical solutions for the displacements, stresses, temperature, diffusion concentration, and volume fraction field with different values of the magnetic field, the rotation, the gravity, and the initial stress are obtained and portrayed graphically. The results indicate that the effects of gravity, rotation, voids, diffusion, initial stress, and electromagnetic field are very pronounced on the physical properties of the material.

基于融合Lasso的非参数加性分位数回归模型

加性分位数回归为非线性关系的建模提供一种灵活、鲁棒的方法.拟合加性分位数模型的方法通常使用样条函数逼近分量,但需要先验的选择节点,计算速度较慢,并不适合大规模数据问题.因此文中提出基于融合Lasso的非参数加性分位数回归模型(Nonparametric Additive Quantile Regression Model Based on Fused Lasso,AQFL),是在融合Lasso罚和l_(2)罚之间折衷的可对加性分位数回归模型进行估计和变量选择的模型.融合Lasso罚使模型能快速计算,并在局部进行自适应,从而实现对所需分位数甚至极端分位数的预测.同时结合l_(2)罚,在高维数据中将对响应影响较小的协变量函数值压缩为零,实现变量的选择.此外,文中给出保证收敛到全局最优的块坐标ADMM算法(Block Coordinate Alternating Direction Method of Multipliers,BC-ADMM),证明AQFL的预测一致性.在合成数据和碎猪肉数据上的实验表明AQFL在预测准确性和鲁棒性等方面较优.

基于SSA_(n)-SSA_(l)-LSTM的短期空调负荷预测模型

本文提出了一种奇异谱分析(SSA_(n))和麻雀搜索算法(SSA_(l))优化的长短期记忆网络(LSTM)的组合空调负荷预测模型。使用皮尔逊相关系数和主成分分析法对输入特征进行挑选和处理,以消除特征之间的冗余性和相关性。针对空调负荷的波动性和随机性,采用SSA_(n)将空调负荷分解为多个分量。同时针对LSTM超参数设置的问题,采用SSA_(l)对模型进行优化,使用优化后的LSTM对各个分量进行预测,对预测结果进行重构。利用办公建筑和医疗建筑的空调负荷数据对模型进行了验证和分析。研究发现,与其他模型相比,SSA_(n)-SSA_(l)-LSTM模型表现最好,在预测办公建筑空调负荷时决定系数(R^(2))高达0.996 7,平均绝对百分比误差(MAPE)、平均绝对误差(MAE)和均方根误差(RMSE)分别为0.62%、14.42 kW和18.82 kW,在预测医疗建筑空调负荷时R^(2)高达0.992 7,MAPE、MAE和RMSE分别为0.50%、19.40 kW和25.71 kW。

Quantitative Assessment of Remotely Sensed Global Surface Models Using Various Land Classes Produced from Landsat Data in Istanbul

Digital elevation model （DEM） is the most popular product for three-dimensional （3D） digital representation of bare Earth surface and can be produced by many techniques with different characteristics and ground sampling distances （GSD）. Space-borne opti- cal and synthetic aperture radar （SAR） imaging are two of the most preferred and modern techniques for DEM generation. Using them, global DEMs that cover almost entire Earth are produced with low cost and time saving processing. In this study, we aimed to assess the Satellite pour robservation de la Terre-5 （SPOT-5）, High Resolution Stereoscopic （HRS）, the Advanced Space-borne Thermal Emission and Reflection Radiometer （ASTER）, and the Shuttle Radar Topography Mission （SRTM） C-band global DEMs, produced with space-borne optical and SAR imaging. For the assessment, a reference DEM derived from 1 ： 1000 scaled digital photogrammetric maps was used. The study is performed in 100 km2 study area in Istanbul including various land classes such as open land, forest, built-up land, scrub and rough terrain obtained from Landsat data. The analyses were realized considering three vertical accuracy types as fundamental, supplemental, and consolidated, defined by national digital elevation program （NDEP） of USA. The results showed that, vertical accuracy of SRTM C-band DEM is better than optical models in all three accuracy types despite having the largest grid spacing. The result of SPOT-5 HRS DEM is very close by SRTM and superior in comparison with ASTER models.

基于WPSO-BP和L-MBWO的多翼离心风机优化研究

针对多翼离心风机气动性能、噪声情况难以同时改进的问题,提出了一种基于变权重粒子群优化算法的反向传播神经网络风机性能预测模型(WPSO-BP),以及一种基于逻辑混沌初始化的多目标白鲸优化算法(L-MBWO),并将二者应用于多翼离心风机的优化设计中。首先,选取了叶片进出口角、倾斜蜗舌的最大蜗舌半径、叶片切除角度作为设计变量,把风机的全压、效率、声压级作为优化目标;然后,构建了WPSO-BP预测模型,以反映设计变量与优化目标之间的关系,定量分析对比了该模型与BP神经网络预测模型,预测值用于风机的性能优化;接着,将逻辑混沌初始化引入到白鲸优化算法(BWO),基于第三代非支配排序遗传算法(NSGA-Ⅲ)构建了L-MBWO优化算法;最后,在实验验证仿真可靠的前提下,将提出的预测模型和优化算法应用于风机优化,并对优化效果进行了综合分析。研究结果表明:优化后的风机全压增加了34.79 Pa,效率提高了0.67%,噪声降低了1.73 dB,实现了多个优化目标之间的平衡,有效改善了风机的综合性能,为多翼离心风机的优化设计提供了一种新思路。