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造纸机分布传动可编程控制器PCC系统的应用
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作者 苏鹏飞 孟磊 《造纸科学与技术》 2024年第2期98-101,共4页
PCC可编程控制器以其强大的数据处理能力、高运算速度和可靠网络连接等优势,在在造纸工业中得到广泛应用,充分发挥其优势有助于推进造纸机的智能化发展、提升造纸机的技术水平。对此,简述了PCC系统控制原理,设计了以PCC B&R 2005为... PCC可编程控制器以其强大的数据处理能力、高运算速度和可靠网络连接等优势,在在造纸工业中得到广泛应用,充分发挥其优势有助于推进造纸机的智能化发展、提升造纸机的技术水平。对此,简述了PCC系统控制原理,设计了以PCC B&R 2005为主控制器、操作面板为人机界面、PROFIBUS现场总线为通信方式的造纸机分布传动控制系统,对系统中主要硬件选型与配置、系统通信方式、下位机软件设计等进行了详细说明,并基于组态王与PCC进行造纸机分布传动上位机监控界面的设计,以期提高造纸机分布传动控制系统的控制精度、实时性和稳定性。 展开更多
关键词 造纸机 分布传动控制系统 可编程控制器pcc 网络通信 监控界面
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Molecular Dynamics, Diffusion Coefficients and Activation Energy of the Electrolyte (Anode) in Lithium (Li and Li+), Sodium (Na and Na+) and Potassium (K and K+)
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作者 Alain Second Dzabana Honguelet Timothée Nsongo +1 位作者 Bitho Rodongo Earvin Loumbandzila 《Modeling and Numerical Simulation of Material Science》 2024年第1期39-57,共19页
This work is a simulation modelling with the LAMMPS calculation code of an electrode based on alkali metals (lithium, sodium and potassium) using the MEAM potential. For different multiplicities, two models were studi... This work is a simulation modelling with the LAMMPS calculation code of an electrode based on alkali metals (lithium, sodium and potassium) using the MEAM potential. For different multiplicities, two models were studied;with and without gap. In this work, we present the structural, physical and chemical properties of the lithium, sodium and potassium electrodes. For the structural properties, the cohesive energy and the mesh parameters were calculated, revealing that, whatever the chemical element selected, the compact hexagonal hcp structure is the most stable, followed by the face-centred cubic CFC structure, and finally the BCC structure. The most stable structure is lithium, with a cohesion energy of -6570 eV, and the lowest bcc-hcp transition energy of -0.553 eV/atom, followed by sodium. For physical properties, kinetic and potential energies were calculated for each of the sectioned chemical elements, with lithium achieving the highest value. Finally, for the chemical properties, we studied the diffusion coefficient and the activation energy. Only potassium followed an opposite order to the other two, with the quantities with lacunae being greater than those without lacunae, whatever the multiplicity. The order of magnitude of the diffusion coefficients is given by the relationship D<sub>Li</sub> > D<sub>Na</sub> > D<sub>k</sub> for the multiplicity 6*6*6, while for the activation energy the order is reversed. 展开更多
关键词 Molecular Dynamics Diffusion coefficients Activation Energy LITHIUM Alkali Metals MEAM Potential
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Adaptive Random Effects/Coefficients Modeling
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作者 George J. Knafl 《Open Journal of Statistics》 2024年第2期179-206,共28页
Adaptive fractional polynomial modeling of general correlated outcomes is formulated to address nonlinearity in means, variances/dispersions, and correlations. Means and variances/dispersions are modeled using general... Adaptive fractional polynomial modeling of general correlated outcomes is formulated to address nonlinearity in means, variances/dispersions, and correlations. Means and variances/dispersions are modeled using generalized linear models in fixed effects/coefficients. Correlations are modeled using random effects/coefficients. Nonlinearity is addressed using power transforms of primary (untransformed) predictors. Parameter estimation is based on extended linear mixed modeling generalizing both generalized estimating equations and linear mixed modeling. Models are evaluated using likelihood cross-validation (LCV) scores and are generated adaptively using a heuristic search controlled by LCV scores. Cases covered include linear, Poisson, logistic, exponential, and discrete regression of correlated continuous, count/rate, dichotomous, positive continuous, and discrete numeric outcomes treated as normally, Poisson, Bernoulli, exponentially, and discrete numerically distributed, respectively. Example analyses are also generated for these five cases to compare adaptive random effects/coefficients modeling of correlated outcomes to previously developed adaptive modeling based on directly specified covariance structures. Adaptive random effects/coefficients modeling substantially outperforms direct covariance modeling in the linear, exponential, and discrete regression example analyses. It generates equivalent results in the logistic regression example analyses and it is substantially outperformed in the Poisson regression case. Random effects/coefficients modeling of correlated outcomes can provide substantial improvements in model selection compared to directly specified covariance modeling. However, directly specified covariance modeling can generate competitive or substantially better results in some cases while usually requiring less computation time. 展开更多
关键词 Adaptive Regression Correlated Outcomes Extended Linear Mixed Modeling Fractional Polynomials Likelihood Cross-Validation Random Effects/coefficients
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Evaluation of the coefficient of lateral stress at rest of granular materials under repetitive loading conditions
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作者 Heerym Han Hyunwook Choo Junghee Park 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1709-1721,共13页
Although the internal stress state of soils can be affected by repetitive loading,there are few studies evaluating the lateral stress(or K_(0))of soils under repetitive loading.This study investigates the changes in K... Although the internal stress state of soils can be affected by repetitive loading,there are few studies evaluating the lateral stress(or K_(0))of soils under repetitive loading.This study investigates the changes in K_(0) and directional shear wave velocity(V_(s))in samples of two granular materials with different particle shapes during repetitive loading.A modified oedometer cell equipped with bender elements and a diaphragm transducer was developed to measure the variations in the lateral stress and the shear wave velocity,under repetitive loading on the loading and unloading paths.The study produced the following results:(1)Repetitive loading on the loading path resulted in an increase in the K_(0) of test samples as a function of cyclic loading number(i),and(2)Repetitive loading on the unloading path resulted in a decrease in K_(0) according to i.The shear wave velocity ratio(i.e.V_(s)(HH)/V_(s)(VH),where the first and second letters in parentheses corresponds to the directions of wave propagation and particle motion,respectively,and V and H corresponds to the vertical and horizontal directions,respectively)according to i supports the experimental observations of this study.However,when the tested material was in lightly over-consolidated state,there was an increase in K_(0) during repetitive loading,indicating that it was the initial K_(0),rather than the loading path,which is responsible for the change in K_(0).The power model can capture the variation in the K_(0) of samples according to i.Notably,the K_(0)=1 line acts as the boundary between the increase and decrease in K_(0) under repetitive loading. 展开更多
关键词 coefficient of lateral stress at rest Repetitive loading Granular materials Shear wave velocity Stiffness anisotropy
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Determination of Natural Logarithm of Diffusion Coefficient and Activation Energy of Thin Layer Drying Process of Ginger Rhizome Slices
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作者 Austin Ikechukwu Gbasouzor Sam Nna Omenyi +1 位作者 Sabuj Mallik Jude E. Njoku 《World Journal of Engineering and Technology》 2024年第1期213-228,共16页
This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhiz... This study is an extension of the previous work done with ARS-680 Environmental Chamber. Drying is a complex operation that demands much energy and time. Drying is essentially important for preservation of ginger rhizome. Drying of ginger was modeled, and then the effective diffusion coefficient and activation energy were determined. For this purpose, the experiments were done at six levels of varied temperatures: 10°C, 20°C, 30°C, 40°C, 50°C and 60°C. The values of effective diffusion coefficients obtained in this work for the variously treated ginger rhizomes closely agreed with the average effective diffusion coefficients of other notable authors who determined the drying kinetics and convective heat transfer coefficients of ginger slices. 展开更多
关键词 Activation Energy Diffusion coefficients Ginger Rhizomes Drying Model Drying Time Moisture Ratio Thin Layer
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Thermomechanical Dynamics (TMD) and Bifurcation-Integration Solutions in Nonlinear Differential Equations with Time-Dependent Coefficients
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作者 Hiroshi Uechi Lisa Uechi Schun T. Uechi 《Journal of Applied Mathematics and Physics》 2024年第5期1733-1743,共11页
The new independent solutions of the nonlinear differential equation with time-dependent coefficients (NDE-TC) are discussed, for the first time, by employing experimental device called a drinking bird whose simple ba... The new independent solutions of the nonlinear differential equation with time-dependent coefficients (NDE-TC) are discussed, for the first time, by employing experimental device called a drinking bird whose simple back-and-forth motion develops into water drinking motion. The solution to a drinking bird equation of motion manifests itself the transition from thermodynamic equilibrium to nonequilibrium irreversible states. The independent solution signifying a nonequilibrium thermal state seems to be constructed as if two independent bifurcation solutions are synthesized, and so, the solution is tentatively termed as the bifurcation-integration solution. The bifurcation-integration solution expresses the transition from mechanical and thermodynamic equilibrium to a nonequilibrium irreversible state, which is explicitly shown by the nonlinear differential equation with time-dependent coefficients (NDE-TC). The analysis established a new theoretical approach to nonequilibrium irreversible states, thermomechanical dynamics (TMD). The TMD method enables one to obtain thermodynamically consistent and time-dependent progresses of thermodynamic quantities, by employing the bifurcation-integration solutions of NDE-TC. We hope that the basic properties of bifurcation-integration solutions will be studied and investigated further in mathematics, physics, chemistry and nonlinear sciences in general. 展开更多
关键词 The Nonlinear Differential Equation with Time-Dependent coefficients The Bifurcation-Integration Solution Nonequilibrium Irreversible States Thermomechanical Dynamics (TMD)
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基于频数统计和χ^(2)-PCC的建筑施工高处坠落事故特征分析 被引量:1
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作者 许浒 陈宇航 +3 位作者 何佳斌 YAHIA Halabi 龙丹冰 赵仕兴 《中国安全科学学报》 CAS CSCD 北大核心 2023年第4期91-99,共9页
为减少建筑施工高坠事故的发生概率,完善相关工程管理质量和技术措施,收集和整理2010—2020年中央住房和城乡建设部等部门公布的746份事故报告,总结事故发生时间、事故等级、直接经济损失、坠落高度、高处作业分类、防护措施和工人年龄... 为减少建筑施工高坠事故的发生概率,完善相关工程管理质量和技术措施,收集和整理2010—2020年中央住房和城乡建设部等部门公布的746份事故报告,总结事故发生时间、事故等级、直接经济损失、坠落高度、高处作业分类、防护措施和工人年龄这7类典型事故特征及相应指标,采用频数统计方法分析事故特征和规律,采用χ^(2)-皮尔逊相关系数(PCC)方法明确各因素间的相关性水平以及影响程度。结果表明:近半数坠落高度发生在二级作业高度范围,超过半数的工人在发生事故时未采取有效防护措施,且坠落高度、死亡人数、直接经济损失和防护措施四者之间的相关性达到显著性水平;防护措施与坠落高度、死亡人数、直接经济损失的相关系数分别为0.119、0.149和0.187,坠落高度与死亡人数相关系数为0.404,直接经济损失和死亡人数的相关系数达0.957,悬空作业与死亡人数相关系数为0.17。此外,目前国内施工现场较低高度的高处作业存在防护盲区,既有防护措施未能有效降低事故严重程度,建议加强对危险区域作业的安全监控,提高伤亡赔偿标准,重视防护用具长期使用后性能劣化情况的检验和抽查。 展开更多
关键词 频数统计 χ^(2)皮尔逊相关系数(pcc) 建筑施工 高处坠落 高处作业 防护措施
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巨藻中谷胱甘肽S转移酶基因对细长聚球藻PCC7942耐镉性的影响 被引量:1
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作者 顾梓鹏 任玉东 +4 位作者 程芬 张晓雯 徐东 叶乃好 梁成伟 《渔业科学进展》 CSCD 北大核心 2023年第2期127-136,共10页
谷胱甘肽S转移酶(glutathione S-transferase, GST)是一个较大的基因家族,在生物体生长发育和对环境变化响应中发挥重要的调控作用。本研究从巨藻(Macrocystis pyrifera)配子体中克隆了6个完整的GST基因(mpgst1、mpgst2、mpgst3、mpgst4... 谷胱甘肽S转移酶(glutathione S-transferase, GST)是一个较大的基因家族,在生物体生长发育和对环境变化响应中发挥重要的调控作用。本研究从巨藻(Macrocystis pyrifera)配子体中克隆了6个完整的GST基因(mpgst1、mpgst2、mpgst3、mpgst4、mpgst5和mpgst6)。随后将6个巨藻GST基因分别转化至细长聚球藻(SynechococcuselongatusPCC7942)中,提取细长聚球藻转化株基因组DNA作为模板进行PCR验证及测定转化株GST酶活进行基因功能验证,结果显示,6个mpgst基因都分别成功整合到细长聚球藻的基因组中,但只有含mpgst1、mpgst4和mpgst6基因的细长聚球藻转化株(MG1、MG4和MG6)具有耐镉性。在镉离子胁迫下,细长聚球藻转化株MG1、MG4和MG6的生长、光合色素含量和叶绿素荧光参数Fv/Fm值均显著高于野生株(P<0.05)。本研究结果为进一步研究巨藻GST基因的抗重金属胁迫功能奠定了基础。 展开更多
关键词 谷胱甘肽S转移酶基因 转基因 镉离子胁迫 巨藻 细长聚球藻pcc7942
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基于GINI-PCC分析方法的批判性思维培养的探索
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作者 王梅 康美玲 《微型电脑应用》 2023年第1期21-23,共3页
批判性思维是当代学生必须具备的一种思维方式,能够促进学生从辩证的角度对待多元化的信息,提高学生的问题思辨能力。以高校计算机专业的研究生为研究对象,采用基尼指数分析学生批判性思维特征的重要性,利用皮尔逊相关系数分析各个特征... 批判性思维是当代学生必须具备的一种思维方式,能够促进学生从辩证的角度对待多元化的信息,提高学生的问题思辨能力。以高校计算机专业的研究生为研究对象,采用基尼指数分析学生批判性思维特征的重要性,利用皮尔逊相关系数分析各个特征相关性,来确定侧重培养的特征。研究发现,通过侧重培养这些特征,学生的批判性思维有明显提高。 展开更多
关键词 批判性思维 基尼指数 皮尔逊相关系数 特征分析
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基于CF-PCCs模型的维西县滑坡致灾因子敏感性分析 被引量:1
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作者 郑景莹 谈树成 +2 位作者 王超 杨贵忠 江龙 《云南大学学报(自然科学版)》 CAS CSCD 北大核心 2023年第2期369-378,共10页
为了深入了解滑坡的成灾背景,减少灾害造成的生命财产损失,以云南省维西县为研究区,选取了高程、坡度、坡向、降水量、距河流距离、工程地质岩组、距断层距离、植被归一化指数(Normalized Difference Vegetation Index,NDVI)和道路密度... 为了深入了解滑坡的成灾背景,减少灾害造成的生命财产损失,以云南省维西县为研究区,选取了高程、坡度、坡向、降水量、距河流距离、工程地质岩组、距断层距离、植被归一化指数(Normalized Difference Vegetation Index,NDVI)和道路密度9项致灾因子,利用确定性系数(Certainty Factor,CF)−皮尔逊积矩相关系数(Pearson Product-moment Correlation Coefficient,PCCs)模型对致灾因子进行敏感性分析,并对分析结果的准确性进行了验证.结果表明:①因子敏感性由高到低分别为坡向、河流、高程、降水量、断层、道路、坡度、工程地质岩组和NDVI;②敏感性最大的因子类别包括:高程为1486~2600 m,坡度为0°~20°,坡向为半阳坡,降水量为782~1178 mm,距河流距离为0~300 m,工程地质岩组为极软岩,距断层距离为2400~3200 m,NDVI为−0.169~0.039,道路密度为80~117 km/km2;③CF-PCCs模型精度高,数据分析结果可靠,该方法可为滑坡敏感性分析提供新思路. 展开更多
关键词 滑坡 CF-pccs模型 敏感性 致灾因子 维西县
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造纸设备新一代PCC可编程计算机控制器应用研究
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作者 王金炜 韩鹏 王军红 《造纸科学与技术》 2023年第4期56-58,88,共4页
随着计算机技术的发展和广泛应用,控制器(PC)已经成为计算机的重要组成部分,几乎所有工业控制都离不开PC机。它是一种高性能、高可靠性、多功能的工业计算机。目前,市面上PC机都可以通过“PCI总线”来连接多个设备,可编程控制器(PLC)是... 随着计算机技术的发展和广泛应用,控制器(PC)已经成为计算机的重要组成部分,几乎所有工业控制都离不开PC机。它是一种高性能、高可靠性、多功能的工业计算机。目前,市面上PC机都可以通过“PCI总线”来连接多个设备,可编程控制器(PLC)是工业控制领域中应用最广泛、技术最成熟、开发周期最短的计算机系统之一,而新一代可编程控制器PCC(ProgrammableCycle-IO)是一种性能优越,功能强大的新型工业计算机。在造纸工业中PCC控制器应用于纸机控制系统中,既可充分发挥其运算速度快、控制精度高、抗干扰能力强等优势,又能有效地降低设备成本和运行费用,提高了纸机自动化程度,从而减少人工干预。 展开更多
关键词 造纸设备 新一代pcc 编程 计算机控制器
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PCC可编程计算机控制器在造纸机变频传动控制系统中的应用 被引量:4
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作者 祝建荣 《中华纸业》 CAS 2023年第10期51-56,共6页
介绍了新一代可编程计算机控制器(PCC)在造纸机变频传动控制系统中的应用。PCC通过RS485串行通讯控制所有变频器。整个系统控制精度高,实时性好,使用效果好。
关键词 造纸机 变频器 pcc RS485串行通讯
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鱼腥藻PCC 7120乙酰辅酶A合成酶All0769的缺失降低异形胞频率
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作者 陈柏楠 余胜超 +2 位作者 袁丽 杨明坤 葛峰 《水生生物学报》 CAS CSCD 北大核心 2023年第7期1025-1035,共11页
研究鉴定了All0769为鱼腥藻PCC 7120中乙酰辅酶A合成酶,通过CRISPR/Cpf1系统敲除鱼腥藻PCC 7120中的乙酰辅酶A合成酶(由all0769编码),探究了乙酰辅酶A合成酶在异形胞分化中的调控机制。结果所示:All0769能在体外反应中催化乙酰辅酶A的... 研究鉴定了All0769为鱼腥藻PCC 7120中乙酰辅酶A合成酶,通过CRISPR/Cpf1系统敲除鱼腥藻PCC 7120中的乙酰辅酶A合成酶(由all0769编码),探究了乙酰辅酶A合成酶在异形胞分化中的调控机制。结果所示:All0769能在体外反应中催化乙酰辅酶A的生成。在供氮环境下,敲除all0769会影响藻细胞生长速率。而无论环境中是否存在化合氮,Δall0769突变株的乙酰辅酶A和α-酮戊二酸含量均显著减少。在供氮环境下,Δall0769突变株中检测到(26.17±1.55)nmol/mg protein的乙酰辅酶A,而在野生型中检测出(43.04±1.09)nmol/mg的乙酰辅酶A。Δall0769突变株的α-酮戊二酸[(1.41±0.24)nmol/mg protein]低于野生型的α-酮戊二酸[(2.13±0.05)nmol/mg protein]。在缺氮环境下,Δall0769突变株中检测到(10.00±2.81)nmol/mg protein的乙酰辅酶A,而在野生型中检测出(29.82±4.04)nmol/mg protein的乙酰辅酶A。Δall0769突变株的α-酮戊二酸含量[(1.48±0.35)nmol/mg protein]低于野生型的α-酮戊二酸[(2.74±0.33)nmol/mg protein]。此外,Δall0769突变株异形胞分化频率(7.12%)显著低于野生型异形胞分化频率(9.22%)。综上所述:文章鉴定了All0769是鱼腥藻PCC 7120中的乙酰辅酶A合成酶。在鱼腥藻PCC 7120中,缺失乙酰辅酶A合成酶(All0769)会减少乙酰辅酶A的含量,进而下调α-酮戊二酸含量使异形胞频率降低。 展开更多
关键词 鱼腥藻pcc 7120 乙酰辅酶A合成酶 乙酰辅酶A Α-酮戊二酸 异形胞
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Advances in joint roughness coefficient (JRC) and its engineering applications 被引量:2
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作者 Nick Barton Changshuo Wang Rui Yong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第12期3352-3379,共28页
The joint roughness coefficient (JRC), introduced in Barton (1973) represented a new method in rock mechanics and rock engineering to deal with problems related to joint roughness and shear strength estimation. It has... The joint roughness coefficient (JRC), introduced in Barton (1973) represented a new method in rock mechanics and rock engineering to deal with problems related to joint roughness and shear strength estimation. It has the advantages of its simple form, easy estimation, and explicit consideration of scale effects, which make it the most widely accepted parameter for roughness quantification since it was proposed. As a result, JRC has attracted the attention of many scholars who have developed JRC-related methods in many areas, such as geological engineering, multidisciplinary geosciences, mining mineral processing, civil engineering, environmental engineering, and water resources. Because of such a developing trend, an overview of JRC is presented here to provide a clear perspective on the concepts, methods, applications, and trends related to its extensions. This review mainly introduces the origin and connotation of JRC, JRC-related roughness measurement, JRC estimation methods, JRC-based roughness characteristics investigation, JRC-based rock joint property description, JRC's influence on rock mass properties, and JRC-based rock engineering applications. Moreover, the representativeness of the joint samples and the determination of the sampling interval for rock joint roughness measurements are discussed. In the future, the existing JRC-related methods will likely be further improved and extended in rock engineering. 展开更多
关键词 Joint roughness coefficient(JRC) Rock joints ROUGHNESS Shear strength Scale effect
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基于PCC可编程计算机控制器的造纸机电控系统程序设计与应用 被引量:2
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作者 祝建荣 《中华纸业》 CAS 2023年第8期32-48,共17页
针对造纸机电控系统的自动控制要求,介绍了基于新一代可编程计算机控制器(PCC)的高速造纸机电控系统程序设计与应用。主站PCC2005与子站PCC2003之间通过CAN现场总线进行组网通讯,并且运用主站PCC2005串行通讯口RS422通讯方式同SSD591全... 针对造纸机电控系统的自动控制要求,介绍了基于新一代可编程计算机控制器(PCC)的高速造纸机电控系统程序设计与应用。主站PCC2005与子站PCC2003之间通过CAN现场总线进行组网通讯,并且运用主站PCC2005串行通讯口RS422通讯方式同SSD591全数字直流调速装置之间构成局域网络以及上位机工控组态软件选用组态王,并与主站PCC2005之间通过串行通讯口RS232通讯方式实现上位机的监控系统,从而实现了造纸机电控系统的网络控制。 展开更多
关键词 造纸机 pcc CAN现场总线 RS422通讯方式 RS232通讯方式 网络控制 组态王 监控系统 SSD591全数字直流调速装置
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Prediction models of the ionization coefficient and ionization cross-section based on multi-layer molecular parameters 被引量:1
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作者 邱睿 周文俊 +2 位作者 郑宇 侯华 王宝山 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第5期93-103,共11页
Prediction models were proposed to estimate the reduced Townsend ionization coefficient and ionization cross-section.A shape function of the reduced Townsend ionization coefficient curves was derived from the ionizati... Prediction models were proposed to estimate the reduced Townsend ionization coefficient and ionization cross-section.A shape function of the reduced Townsend ionization coefficient curves was derived from the ionization collision probability model.The function had three parameters:the first ionization potential energy,A_(α),and B_(α).A_(α)and B_(α)were related to the molecule symmetry and size.The polarization of molecules could characterize the molecule symmetry.The multi-layer molecular cross-section(MMCS)was proposed to describe the contributions of electrons and molecule radius on different molecule surfaces to collisions.A prediction model of the ionization cross-section was also proposed based on Aα.The molecule parameters were calculated by the Becke3–Lee–Yang–Parr(B3LYP)method and the 6–311G**basis set.We used available data of 30 and 23 gases,respectively,to build the prediction models of reduced Townsend ionization coefficients and ionization cross-sections.The relationships between the molecular parameters Aαand Bαand the ionization cross-section were built up via nonlinear fittings.The determination coefficients R^(2)of Aα,Bα,and the ionization cross-section were 0.877,0.887,and 0.838,respectively.The results showed that the accuracy of models was positively correlated with the molecule symmetry and reduced electric field.This was mainly related to the accuracy of the MMCS model in predicting Aα.The MMCS model needed to be improved to describe the collision direction selectivity caused by the molecule asymmetry.Under a high reduced electric field,that error of Aαhad less influence on the prediction results.However,the prediction results for single atoms with high symmetry were poor.This may be due to the absolute error of the model close to single atoms’reduced Townsend ionization coefficients.The models could provide the basis for gas insulation prediction and discharge calculations,especially for symmetric molecules under a high electric field. 展开更多
关键词 Townsend ionization coefficient ionization cross-section gas discharge eco-friendly insulation gases
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Analysis of burnup performance and temperature coefficient for a small modular molten‑salt reactor started with plutonium 被引量:1
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作者 Xue‑Chao Zhao Yang Zou +1 位作者 Rui Yan Xiang‑Zhou Cai 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第1期178-189,共12页
In a thorium-based molten salt reactor(TMSR),it is difficult to achieve the pure 232Th–^(233)U fuel cycle without sufficient^(233)U fuel supply.Therefore,the original molten salt reactor was designed to use enriched ... In a thorium-based molten salt reactor(TMSR),it is difficult to achieve the pure 232Th–^(233)U fuel cycle without sufficient^(233)U fuel supply.Therefore,the original molten salt reactor was designed to use enriched uranium or plutonium as the starting fuel.By exploiting plutonium as the starting fuel and thorium as the fertile fuel,the high-purity^(233)U produced can be separated from the spent fuel by fluorination volatilization.Therefore,the molten salt reactor started with plutonium can be designed as a^(233)U breeder with the burning plutonium extracted from a pressurized water reactor(PWR).Combining these advantages,the study of the physical properties of plutonium-activated salt reactors is attractive.This study mainly focused on the burnup performance and temperature reactivity coefficient of a small modular molten-salt reactor started with plutonium(SM-MSR-Pu).The neutron spectra,^(233)U production,plutonium incineration,minor actinide(MA)residues,and temperature reactivity coefficients for different fuel salt volume fractions(VF)and hexagon pitch(P)sizes were calculated to analyze the burnup behavior in the SM-SMR-Pu.Based on the comparative analysis results of the burn-up calculation,a lower VF and larger P size are more beneficial for improving the burnup performance.However,from a passive safety perspective,a higher fuel volume fraction and smaller hexagon pitch size are necessary to achieve a deep negative feedback coefficient.Therefore,an excellent burnup performance and a deep negative temperature feedback coefficient are incompatible,and the optimal design range is relatively narrow in the optimized design of an SM-MSR-Pu.In a comprehensive consideration,P=20 cm and VF=20%are considered to be relatively balanced design parameters.Based on the fuel off-line batching scheme,a 250 MWth SM-MSR-Pu can produce approximately 29.83 kg of ^(233)U,incinerate 98.29 kg of plutonium,and accumulate 14.70 kg of MAs per year,and the temperature reactivity coefficient can always be lower than−4.0pcm/K. 展开更多
关键词 Molten salt fuel Incinerate plutonium 233U production Temperature reactivity coefficient
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基于PCC和KELM的电力系统暂态稳定分析方法
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作者 肖兵 张雅婷 +1 位作者 刘颂凯 张磊 《内蒙古电力技术》 2023年第3期57-62,共6页
为准确及时地监测电力系统的运行状态,提出一种基于皮尔逊相关系数(Pearson Correlation Coefficient,PCC)和核极限学习机(Kernel Extreme Learning Machine,KELM)的电力系统暂态稳定分析方法。首先,利用电力系统仿真软件PSS/E进行数据... 为准确及时地监测电力系统的运行状态,提出一种基于皮尔逊相关系数(Pearson Correlation Coefficient,PCC)和核极限学习机(Kernel Extreme Learning Machine,KELM)的电力系统暂态稳定分析方法。首先,利用电力系统仿真软件PSS/E进行数据生成;然后,使用PCC对电力系统运行特征进行相关性检测,进而选出关键特征;最后,对KELM模型进行训练。在实际应用时,当相量测量单元(Phasor Measurement Unit,PMU)所采集的电力系统实时运行信息被发送到训练好的KELM模型时,可立即提供暂态稳定分析结果。此外,设计了模型更新过程以应对电力系统运行条件的变化,并在新英格兰10机39节点系统验证了该方法的有效性。 展开更多
关键词 核极限学习机 暂态稳定 皮尔逊相关系数 相量测量单元 输入特征
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基于PCC-ISSA-BP燃料电池剩余寿命预测
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作者 方娜 肖威 邓心 《电子测量技术》 北大核心 2023年第24期77-83,共7页
在质子交换膜燃料电池(PEMFC)寿命预测中,针对燃料电池中的特征对其寿命的影响程度未知问题,使预测燃料电池的剩余寿命问题变得相对复杂,为了更加准确的预测燃料电池的剩余使用寿命。本文首先通过小波分析对原始堆栈电压进行去噪处理,... 在质子交换膜燃料电池(PEMFC)寿命预测中,针对燃料电池中的特征对其寿命的影响程度未知问题,使预测燃料电池的剩余寿命问题变得相对复杂,为了更加准确的预测燃料电池的剩余使用寿命。本文首先通过小波分析对原始堆栈电压进行去噪处理,滤除噪声数据,利用皮尔逊相关系数(PCC)对影响因素进行降维,提取关键影响因素,简化模型结构;然后利用改进的麻雀优化算法(ISSA)优化BP神经网络,找到网络最优的权值和阈值,并建立ISSABP模型;最后将处理好的数据输入ISSA-BP模型,实现PEMFC的剩余寿命预测。实验结果表明,PCC-ISSA-BP的平均绝对误差百分比、平均绝对误差、均方根误差分别为0.125%、0.00397、0.00568,优于其它模型,能够更有效地预测燃料电池的剩余寿命。 展开更多
关键词 燃料电池 小波分析 皮尔逊相关系数 BP神经网络 改进麻雀优化算法
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Determination of rock mass integrity coefficient using a non-invasive geophysical approach 被引量:1
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作者 Muhammad Hasan Yanjun Shang +2 位作者 Xuetao Yi Peng Shao Meng He 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第6期1426-1440,共15页
Determination of rock mechanical parameters is the most important step in rock mass quality evaluation and has significant impacts on geotechnical engineering practice.Rock mass integrity coefficient(KV)is one of the ... Determination of rock mechanical parameters is the most important step in rock mass quality evaluation and has significant impacts on geotechnical engineering practice.Rock mass integrity coefficient(KV)is one of the most efficient parameters,which is conventionally determined from boreholes.Such approaches,however,are time-consuming and expensive,offer low data coverage of point measurements,require heavy equipment,and are hardly conducted in steep topographic sites.Hence,borehole approaches cannot assess the subsurface thoroughly for rock mass quality evaluation.Alternatively,use of geophysical methods is non-invasive,rapid and economical.The proposed geophysical approach makes useful empirical correlation between geophysical and geotechnical parameters.We evaluated the rock mass quality via integration between KV measured from the limited boreholes and inverted resistivity obtained from electrical resistivity tomography(ERT).The borehole-ERT correlation provided KV along various geophysical profiles for more detailed 2D/3D(two-/three-dimensional)mapping of rock mass quality.The subsurface was thoroughly evaluated for rock masses with different engineering qualities,including highly weathered rock,semi-weathered rock,and fresh rock.Furthermore,ERT was integrated with induced polarization(IP)to resolve the uncertainty caused by water/clay content.Our results show that the proposed method,compared with the conventional approaches,can reduce the ambiguities caused by inadequate data,and give more accurate insights into the subsurface for rock mass quality evaluation. 展开更多
关键词 Geotechnical engineering Rock mass integrity coefficient Rock mechanical parameters Geophysical parameters Electrical resistivity tomography(ERT) Induced polarization(IP)
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