A novel rapid cooling assembly design in a high-pressure cubic press apparatus

In traditional high-pressure–temperature assembly design, priority has been given to temperature insulation and retention at high pressures.This limits the efficiency of cooling of samples at the end of experiments, with a negative impact on many studies in high-pressure Earth andplanetary science. Inefficient cooling of experiments containing molten phases at high temperature leads to the formation of quench textures,which makes it impossible to quantify key compositional parameters of the original molten phase, such as their volatile contents. Here,we present a new low-cost experimental assembly for rapid cooling in a six-anvil cubic press. This assembly not only retains high heatingefficiency and thermal insulation, but also enables a very high cooling rate (∼600 ℃/s from 1900 ℃ to the glass transition temperature).Without using expensive materials or external modification of the press, the cooling rate in an assembly (∼600 ℃/s) with cube lengths of38.5 mm is about ten times faster than that in the traditional assembly (∼60 ℃/s). Experiments yielding inhomogeneous quenched melttextures when the traditional assembly is used are shown to yield homogeneous silicate glass without quench textures when the rapid coolingassembly is used.

Synthesizing active and durable cubic ceria catalysts(<6 nm)for fast dehydrogenation of bio-polyols to carboxylic acids coproducing green H_(2)

Dehydrogenation is considered as one of the most important industrial applications for renewable energy.Cubic ceria-based catalysts are known to display promising dehydrogenation performances in this area.Large particle size(>20 nm)and less surface defects,however,hinder further application of ceria materials.Herein,an alternative strategy involving lactic acid(LA)assisted hydrothermal method was developed to synthesize active,selective and durable cubic ceria of<6 nm for dehydrogenation reactions.Detailed studies of growth mechanism revealed that,the carboxyl and hydroxyl groups in LA molecule synergistically manipulate the morphological evolution of ceria precursors.Carboxyl groups determine the cubic shape and particle size,while hydroxyl groups promote compositional transformation of ceria precursors into CeO_(2) phases.Moreover,enhanced oxygen vacancies(Vo)on the surface of CeO_(2) were obtained owing to continuous removal of O species under reductive atmosphere.Cubic CeO_(2) catalysts synthesized by the LA-assisted method,immobilized with bimetallic PtCo clusters,exhibit a record high activity(TOF:29,241 h^(-1))and Vo-dependent synergism for dehydrogenation of bio-derived polyols at 200℃.We also found that quenching Vo defects at air atmosphere causes activity loss of PtCo/CeO_(2) catalysts.To regenerate Vo defects,a simple strategy was developed by irradiating deactivated catalysts using hernia lamp.The outcome of this work will provide new insights into manufacturing durable catalyst materials for aqueous phase dehydrogenation applications.

A Mathematical Modeling of 3D Cubical Geometry Hypothetical Reservoir under the Effect of Nanoparticles Flow Rate,Porosity,and Relative Permeability

This study aims to formulate a steady-state mathematical model for a three-dimensional permeable enclosure(cavity)to determine the oil extraction rate using three distinct nanoparticles,SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3),in unconventional oil reservoirs.The simulation is conducted for different parameters of volume fractions,porosities,and mass flow rates to determine the optimal oil recovery.The impact of nanoparticles on relative permeability(kr)and water is also investigated.The simulation process utilizes the finite volume ANSYS Fluent.The study results showed that when the mass flow rate at the inlet is low,oil recovery goes up.In addition,they indicated that silicon nanoparticles are better at getting oil out of the ground(i.e.,oil reservoir)than Al_(2)O_(3)and Fe_(2)O_(3).Most oil can be extracted from SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3)at a rate of 97.8%,96.5%,and 88%,respectively.

Metastable face-centered cubic ruthenium-based binary alloy for efficient alkaline hydrogen oxidation electrocatalysis

Metastable nanostructured electrocatalyst with a completely different surface environment compared to conventional phase-based electrocatalyst often shows distinctive catalytic property.Although Ru-based electrocatalysts have been widely investigated toward hydrogen oxidation reaction(HOR)under alkaline electrolytes,these studies are mostly limited to conventional hexagonal-close-packed(hcp)phase,mainly arising from the lack of sufficient synthesis strategies.In this study,we report the precise synthesis of metastable binary RuW alloy with face-centered-cubic(fcc)phase.We find that the introduction of W can serve as fcc phase seeds and reduce the formation energy of metastable fcc-RuW alloy.Impressively,fcc-RuW exhibits remarkable alkaline HOR performance and stability with the activity of 0.67 mA cm_(Ru)^(-2)which is almost five and three times higher than that of hcp-Ru and commercial Pt/C,respectively,which is attributed to the optimized binding strength of adsorbed hydroxide intermediate derived from tailored electronic structure through W doping and phase engineering.Moreover,this strategy can also be applied to synthesize other metastable fcc-RuCr and fcc-RuMo alloys with enhanced HOR performances.

High-Quality and Wafer-Scale Cubic Silicon Carbide Single Crystals

Cubic silicon carbide(3C-SiC)has superior mobility and thermal conduction over that of widely applied hexagonal 4H-SiC.Moreover,much lower concentration of interfacial traps between insulating oxide gate and 3C-SiC helps fabricate reliable and long-life devices like metal-oxidesemiconductor field effect transistors.However,the growth of high-quality and wafer-scale 3C-SiC crystals has remained a big challenge up to now despite decades-long efforts by researchers because of its easy transformation into other polytypes during growth,limiting the development of 3C-SiC-based devices.Herein,we report that 3C-SiC can be made thermodynamically favored from nucleation to growth on a 4H-SiC substrate by top-seeded solution growth technique,beyond what is expected by classical nucleation theory.This enables the steady growth of high-quality and large-size 3C-SiC crystals(2-4-inch in diameter and 4.0-10.0 mm in thickness)sustainable.The as-grown 3C-SiC crystals are free of other polytypes and have high-crystalline quality.Our findings broaden the mechanism of hetero-seed crystal growth and provide a feasible route to mass production of 3C-SiC crystals,offering new opportunities to develop power electronic devices potentially with better performances than those based on 4H-SiC.

ANovel Non-Isolated Cubic DC-DC Converter with High Voltage Gain for Renewable Energy Power Generation System

In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.

Accounting for Quadratic and Cubic Invariants in Continuum Mechanics–An Overview

The differential equations of continuum mechanics are the basis of an uncountable variety of phenomena and technological processes in fluid-dynamics and related fields.These equations contain derivatives of the first order with respect to time.The derivation of the equations of continuum mechanics uses the limit transitions of the tendency of the volume increment and the time increment to zero.Derivatives are used to derive the wave equation.The differential wave equation is second order in time.Therefore,increments of volume and increments of time in continuum mechanics should be considered as small but finite quantities for problems of wave formation.This is important for calculating the generation of sound waves and water hammer waves.Therefore,the Euler continuity equation with finite time increments is of interest.The finiteness of the time increment makes it possible to take into account the quadratic and cubic invariants of the strain rate tensor.This is a new branch in hydrodynamics.Quadratic and cubic invariants will be used in differential wave equations of the second and third order in time.

Effect of Size and Initial Water Content on the Effective Diffusion Coefficient during Convective Drying of Sweet Potato Cut into Cubic and Cylindrical Shapes

In this article, we investigated the influence of size and initial water content on the effective diffusion coefficient of sweet potatoes samples cut into cubic and cylindrical shapes. The sizes of the cubic samples are 0.5, 1, 1.5, 1.75, 2, 2.5 and 3 cm edge with a respective initial water content of 2.7, 3.76, 3.48, 2.68, 3.28, 2.17 and 2.29 kg/kgms. For cylindrical samples, the radius is set at 0.5 cm and sample heights are 1, 1.5, 2, 2.5, 3, 3.5 and 4 cm with respective water contents of 2.2, 3.19, 2.85, 2.1, 2.17, 2.39 and 2.03 kg/kgms. The effective diffusion coefficients of cubic samples are of the order of 10−10 and 10−9 m2∙s−1 grew with sample edge. As for the cylindrical samples, the effective diffusion coefficients were of the order of 10−9 m2∙s−1 and there was no linear correlation between cylinder height and their effective diffusion coefficient. As for the examination of the initial water content on the effective diffusion coefficient, it turned out that the initial water content had no influence on the effective diffusion coefficient of the sweet potato samples.

某院药品消耗指数与DRG超支的相关性及阈值效应分析

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。

血红蛋白/红细胞分布宽度比值与肺栓塞患者预后的相关性

目的探讨血红蛋白/红细胞分布宽度比值(hemoglobin/red blood cell distribution width ratio,HRR)与肺栓塞患者病死率的相关性及预后预测价值。方法本研究对MIMIC-Ⅳ(v2.2)中的肺栓塞患者进行回顾性研究。主要结局为院内死亡,次要结局为出ICU 7天、30天病死率。采用逻辑回归和限制性立方样条(RCS)探讨HRR与肺栓塞患者病死率的相关性;应用受试者工作特征(ROC)曲线分析HRR对肺栓塞患者的预后预测价值;通过亚组分析和似然比检验的交互作用检验来评估研究结果的稳健性。收集2021年1月1日至2023年12月31日入住山东中医药大学附属医院周围血管病科及重症医学科肺栓塞患者的临床数据,对肺栓塞与HRR预后相关性进行验证。结果本研究共纳入2282例肺栓塞患者,根据HRR的三分位数分成Q1组(<0.81)、Q2组(0.81~0.99)、Q3组(>0.99)。逻辑回归模型分析院内病死率时,在校正模型3中,HRR与院内病死率呈负相关(OR=0.202,95%CI 0.063~0.654)。RCS曲线进一步验证其具有线性相关性。ROC曲线分析院内死亡风险时,曲线下面积(AUC)为0.6424(95%CI 0.5863~0.6985),HRR具有显著预测优势。在亚组分析中,除婚姻-其他组(P=0.068)、种族-黑人组(P=0.497)、连续性肾脏替代治疗(CRRT)-是组(P=0.522)外,肺栓塞患者院内病死率的相关性稳定(P<0.05)。除下肢深静脉血栓形成组(交互作用P=0.019)、糖尿病组(交互作用P=0.019)外,HRR与其他各组无显著交互作用(交互作用P=0.152~0.821)。收集国内肺栓塞患者临床数据应用ROC曲线加以验证,AUC为0.8515(95%CI 0.7455~0.9575)。结论HRR与肺栓塞患者病死率具有显著的线性负相关性,且HRR是相对独立的预测因子。

Cubic B样条旋转曲面的自由绘制技术

随着基于样条曲线的模型逐渐成为CAGD的主要研究对象,进一步带动了高度自由曲面建模技术的发展.本文描述一个新颖、直观的旋转曲面绘制技术,它支持三次B样条的自由输入作为轮廓线,并通过提取的样点矢量以及最小方差逼近方法形成旋转轴,利用轴上测量点的切线方向确定各个圆平面,从而建立了平面上旋转坐标矩阵,最终插值空间球面样点生成双三次B样条曲面.实验结果有效地验证了此技术的高效性.

双正交Hermite Cubics的对称预滤波设计

将多小波预滤波器设计的"超函数"法推广到了双正交系统,得到使联合滤波器具有m阶平衡的条件,并针对双正交Hermite Cubics,分别设计了使系统具有2阶平衡与4阶平衡的对称预滤波器.

Anti-Plane Elasticity Problem and Mode Ⅲ Crack Problem of Cubic Quasicrystal

The fracture theory of cubic quasicrystal was developed. The exact analytic solution of a Mode Ⅲ Griffith crack in the material was obtained by using the Fourier transform and dual integral equations theory, and so the displacement and stress fields, the stress intensity factor and strain energy release rate were determined. The results show that the stress intensity factor is independent of material constants, and the strain energy release rate is dependent on all material constants. These provide important information for studying the deformation and fracture of the new solid material.

Application of face centred cubic TiB powder as conductive filler for electrically conductive adhesives

Face centred cubic（FCC） TiB ceramic powder synthesized by Ti-boronizing method was used as conductive filler to make ceramic electrically conductive adhesives（ECAs） with the polymer matrix.Electrically conductive properties of the ceramic ECAs were studied.The bulk electrical resistivity varied with the powder content of the FCC-TiB in ECAs.The FCC-TiB filled ECAs also showed the percolation behavior that usually occurred for the metal-filled ECAs,the percolation threshold was located at the content of 60%FCC-TiB.A minimum value of 0.1 Ω·cm was obtained at a content of 75%FCC-TiB.In order to check the reliability of mechanical property,tensile test was done to measure the shear strength,and the shear strength dropped with increasing the content of FCC-TiB powders.It is about 12.26 MPa at the content of 70%TiB powders.The Cu filled ECAs were also prepared for comparison.The properties of the oxidation resistance of the two ECAs were evaluated.The results show that the ceramic ECAs have excellent oxidation resistance and better stability compared with the Cu filled ECAs.

使用鱼眼镜头制作QuickTime CubicVR

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。

中小学生高度近视发生风险预测模型:基于巢式病例对照研究

背景中小学生由于学习压力、电子产品普及以及不良用眼习惯,视力健康问题日益严重,成为近视的高发群体,高度近视作为近视的严重阶段,已成为全球范围内的公共卫生问题。尽管现有诸多研究对近视的危险因素进行了探讨,但鲜有研究针对性阐明风险因素与高度近视发生的复杂非线性关系,本研究结合巢式病例对照研究和限制性立方样条,开发一个中小学生高度近视风险预测模型,通过早期识别高风险个体,延缓或阻止高度近视的发展,实现近视的三级预防,对中小学生的学业和生活质量有积极意义。目的探究中小学生高度近视的流行现状及危险因素,构建风险预测模型,为中小学生高度近视防控提供科学依据。方法采用巢式病例对照研究,于2023年选取杭州市12所学校中度近视的学生作为研究对象建立队列,按照全国学生常见病和健康影响因素监测与干预工作方案,对纳入研究的中小学生开展近视状况监测,研究期间进展为高度近视的中小学生作为高度近视发生组,其余未进展为高度近视的中小学生作为对照组,对两组研究对象开展视力保健行为进行调查。采用Lasso回归筛选特征变量后进行多因素Logistic回归分析探究中小学生高度近视发生的影响因素,并采用列线图对风险预测模型可视化,同时采用Hosmer-Lemeshow检验、受试者工作特征(ROC)曲线、Calibration曲线、决策曲线分析(DCA)对模型性能进行评估,最后采用限制性立方样条进一步明确年龄与高度近视发生风险的关系。结果12所中小学校共纳入2468名学生,未进展为高度近视的学生1293名,中度近视进展为高度近视的学生1175名,高度近视发生率为47.61%(1175/2468)。两组学生年龄、年级、BMI、每日入睡时间、地区、户外活动时间、电子产品使用时间、课后作业时间、家用台灯比较,差异有统计学意义(P<0.05)。Lasso回归筛选出8个特征变量:年级、BMI、每日入睡时间、地区、户外活动时间、电子产品使用时间、课后作业时间、家用台灯。多因素Logistic回归分析结果显示,初中年级(OR=2.612,95%CI=2.185~3.127),超重或肥胖(OR=2.140,95%CI=1.458~3.169)、偏瘦(OR=1.807,95%CI=1.430~2.290),每日入睡时间在22:00之后(OR=1.408,95%CI=1.188~1.670),户外活动时间1~2 h/d(OR=1.371,95%CI=1.122~1.675)、<1 h/d(OR=1.648,95%CI=1.342~2.027),电子产品使用时间>2 h/d(OR=1.440,95%CI=1.119~1.856),课后作业时间1~2 h/d(OR=1.461,95%CI=1.126~1.899)、>2 h/d(OR=1.534,95%CI=1.218~1.935)为中小学生高度近视发生的危险因素(P<0.05);而高中年级(OR=0.560,95%CI=0.419~0.743)为中小学生高度近视发生的保护因素(P<0.05)。基于年级、BMI、每日入睡时间、户外活动时间、电子产品使用时间、课后作业时间等6个变量构建的预测模型ROC曲线下面积为0.840(95%CI=0.825~0.855),具有良好的拟合优度、一致性、应用性,限制性立方样条分析显示13~15岁为高度近视的高发年龄段。结论中小学生高度近视发生率较高,风险预测模型为高度近视的预防和控制提供了科学依据,应在初中年级加强近视防控措施,改善学生的视力保健行为,降低高度近视的发生。

基于Hermite Cubics的预滤波器与双正交平衡系统

首先将正交多小波系统的平衡性理论及预滤波理论推广到双正交系统,在此基础上,从不具有平衡性的Hermite Cubics双正交多小波出发,得到两组使系统的"低通"滤波器保持三阶多项式信号的预滤波器,最后给出一组基于Hermite Cubics系统的具有一阶平衡性的双正交多小波系统.

Growth of Cubic GaN by MOCVD at High Temperature

High quality cubic GaN (c GaN) is grown by metalorganic vapor deposition (MOCVD) at an increased growth temperature of 900℃,with the growth rate of 1 6μm/h.The full width at half maximum (FWHM) of room temperature photoluminescence (PL) for the high temperature grown GaN film is 48meV.It is smaller than that of the sample grown at 830℃.In X ray diffraction (XRD) measurement,the high temperature grown GaN shows a (002) peak at 20° with a FWHM of 21′.It can be concluded that,although c GaN is of metastable phase,high growth temperature is still beneficial to the improvement in its crystal quality.The relationship between the growth rate and growth temperature is also discussed.

基于形态学算子的Cubic图像缩放方法

立方卷积插值(Cubic算法)是一种常用的图像缩放方法。为了使喷码机喷印图像更加清晰可见,改善Cubic算法边缘模糊、分辨率低等不足,本文将形态学算子中的腐蚀运算与Cubic算法结合,以此进行了理论分析和实验验证。结果表明,此方法对提高图像边缘的清晰度和图像质量有明显效果。

解BBMB方程的改进三次B样条配置法

使用一种改进的三次B样条配置法求解Benjamin-Bona-Mahony-Burgers(BBMB)方程.通过限制标准三次B样条高阶导数,利用Crank-Nicolson格式将时间离散化,并采用线性化过程处理非线性项,结合空间上改进的三次B样条函数离散化,实现了对BBMB方程的高效数值求解.通过Von-Neumann稳定性分析,验证了该方法的稳定性.数值实验表明,该方法在空间上达到六阶收敛精度.