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Non-Darcy flows in layered porous media(LPMs)with contrasting pore space structures

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Petroleum Science 2022年第5期19卷 2004-2013页

作者： xue-yi Zhang Zhi Dou Jin-Guo Wang Zhi-Fang Zhou Chao Zhuang School of Earth Sciences and Engineering Hohai UniversityNanjing 210098JiangsuChina

Compared to single layer porous media,fluid flow through layered porous media(LPMs)with contrasting pore space structures is more *** study constructed three-dimensional(3-D)pore-scale LPMs with different grain size ratios of 1.20,1.47,and *** flow behavior in the constructed LPMs and single layer porous media was numerically investigated.A total of 178 numerical experimental data were collected in LPMs and single layer porous *** all cases,two different flow regimes(i.e.,Darcy and Non-Darcy)were *** influence of the interface of layers on Non-Darcy flow behavior in LPMs was analyzed based pore-scale flow *** was found that the available correlations based on single layer porous media fail to predict the flow behavior in LPMs,especially for LPM with large grain size *** effective permeability,which incorporated the influence of the interface is more accurate than the Kozeny-Carman equation for estimating the Darcy permeability of *** inertial pressure loss in LPMs,which determines the onset of the Non-Darcy flow,was underestimated when using a power law expression of mean grain *** constant B,an empirical value in the classical Ergun equation,typically equals *** inertial pressure loss in LPMs can be significantly different from it in single lager porous *** Non-Darcy flow in LPMs,it is necessary to consider a modified larger constant B to improve the accuracy of the Ergun empirical equation.

关键词： Non-Darcy flow Layered porous media Heterogeneity Forchheimer equation Simulations

Performance of the CENDL-3.2 and other major neutron data libraries for criticality calculations

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Nuclear Science and Techniques 2022年第1期33卷 81-97页

作者： Bin Zhang Xu-Bo Ma Kui Hu Teng Zhang Xuan Ma yi-xue Chen School of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China

Nuclear data are the cornerstones of reactor physics and shielding ***,China released CENDL-3.2 in 2020,and the US released ENDF/B-VIII.0 in ***,it is necessary to comprehensively evaluate the criticality computing performance of these newly released evaluated nuclear *** this study,we used the NJOY2016 code to generate ACE format libraries based on the latest neutron data libraries(including CENDL-3.2,JEFF3.3,ENDF/B-VIII.0,and JENDL4.0).The MCNP code was used to conduct a detailed analysis of fission nuclides,including^(235)U,^(233)U,and^(239)Pu,in different evaluated nuclear data libraries based on 100 *** criticality calculation performance of each library was evaluated using three statistical parameters:δk/σ,χ^(2),and.Analysis of theδk/σparameter showed that CENDL-3.1 and JENDL-4.0 both had>10 benchmarks that exceeded 3r,whereas CENDL3.2,ENDFB-VIII.0,and JEFF-3.3 had,7,5,and 4 benchmarks,respectively,exceeding *** ENDF/B-VII.1 library performed best,with only two benchmarks exceeding *** to CENDL-3.1,CENDL-3.2 offers an improvement in criticality *** to the JEFF-3.3 and ENDF/B-VIII.0 libraries,CENDL3.2 performs better in the calculation of the^(233)U assemblies,but it performs poorly in the pusl11 series case calculation of the^(239)Pu assemblies,and thus further improvement is needed.

关键词： Criticality calculations CENDL-3.2 ENDF/B-VIII.0 Neutron ACE library

Experimental investigations on effects of gas pressure on mechanical behaviors and failure characteristic of coals

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第2期15卷 412-428页

作者： yi xue P.G.Ranjith Feng Gao Zhizhen Zhang Songhe Wang State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an710048China Deep Earth Energy Laboratory Department of Civil EngineeringMonash UniversityBuilding 60MelbourneVictoria3800Australia State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221006China

The mechanical behavior of coal is the key factor affecting underground coal mining and coalbed methane *** this study,triaxial compression and seepage tests were carried out on coal at different gas *** mechanical properties and failure process of coal were studied,as well as the acoustic emission(AE)and strain *** influence of gas pressure on the mechanical parameters of this coal was *** on the conventional energy calculation formula,the pore pressure was introduced through the effective stress formula,and each energy component of coal containing gas was refined *** contribution of gas pressure to the total energy input and dissipation during loading was quantitatively ***,the influence of gas pressure on coal strength was theo-retically analyzed from the perspectives of MohreCoulomb criterion and fracture *** results show that the total absorbed energy comprises the absorbed energy in the axial pressure direction(positive)and in the confining pressure direction(negative),as well as that induced by the pore pressure(initially negative and then positive).The absorbed energy in the axial pressure direction accounts for the main proportion of the total energy absorbed by *** quiet period of AE in the initial stage shortens,and AE activity increases during the pre-peak stage under high gas *** fractal characteristics of AE in three stages are studied using the correlation *** AE process has different forms of self-similarity in various deformation stages.

关键词： Coal Gas pressure Acoustic emission(AE) Strain energy Fractal characteristics

Tungsten doping La_(0.6)Ca_(0.4)Fe_(0.8)Ni_(0.2)O_(3-δ)as electrode for highly efficient and stable symmetric solid oxide cells

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Tungsten 2023年第4期5卷 598-606页

作者： Xin-yi Jiao Ao-Yan Geng yi-Yang xue Xing-Bao Wang Fang-Jun Jin yi-Han Ling Yun-Feng Tian School of Materials Science and Physics China University of Mining and TechnologyXuzhou221116China State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan030024China

Perovskite oxide La_(0.6)Ca_(0.4)Fe_(0.8)Ni_(0.2)O_(3-δ)(LCFN)has been used in symmetric solid oxide cells(SSOCs)to obtain good electrochemical performance in both fuel cells(SOFCs)and electrolysis cells(SOECs)***,its structural stability still faces challenges and the electrocatalytic activity also needs to be further ***,tungsten-doped La_(0.6)Ca_(0.4)Fe_(0.7)Ni_(0.2)W_(0.1)0_(3-δ)(LCFNW)perovskite oxide material was synthesized which exhibits good structural stability under H_(2)and superior electrochemical performance as an electrode for *** SOFCs mode,the cell achieved the maximum power density of 0.58 W·cm^(-2)with wet H_(2)as fuel at 850℃.In SOECs mode,the current density can reach 1.81 A·cm^(-2)for pure CO_(2)electrolysis at 2 ***,the SSOCs exhibits outstanding long-term stability in both SOFCs and SOECs modes,proving that doping W in perovskite oxide is an effective strategy to enhance the catalytic activity and stability of the *** LCFNW material developed in this work shows promising prospect as an electrode candidate for SSOCs.

关键词： Symmetric solid oxide cells Perovskite oxide La_(0.6)Ca_(0.4)Fe_(0.8)Ni_(0.2)O_(3-δ) CO_(2)electrolysis Stability

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飞轮锂电池混合储能系统的VSG控制策略

黑龙江科技大学学报 2024年第1期34卷 132-137页

作者：薛易李天意吴立涵龙腾飞黑龙江科技大学电气与控制工程学院哈尔滨150022

为提升电网电能质量,抑制电网在运行过程的频率和电压超波动,采用飞轮锂电池混合储能系统进行波动平抑,考虑飞轮作用时间短,蓄电池作用时间长,在VSG控制中引入一阶高通滤波器,通过蓄电池参与一次调频,飞轮参与调压。结果表明,该策略能... 详细信息

为提升电网电能质量,抑制电网在运行过程的频率和电压超波动,采用飞轮锂电池混合储能系统进行波动平抑,考虑飞轮作用时间短,蓄电池作用时间长,在VSG控制中引入一阶高通滤波器,通过蓄电池参与一次调频,飞轮参与调压。结果表明,该策略能够实现电压维持在690 V,频率维持在50 Hz,实现了对频率和电压良好平抑,具有很好的鲁棒性。

关键词：混合储能系统虚拟同步发电机波动平抑

基于Logistic回归和支持向量机的早发性结直肠癌风险预测模型

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中国现代普通外科进展 2024年第3期27卷 195-198页

作者：薛亦诚刘超杨贵淞齐宏青岛大学附属青岛市市立医院胃肠外二科山东青岛266071

目的:通过Logis tic回归和支持向量机(SVM)探究早发性结直肠癌(EOCRC)和晚发性结直肠癌(LOCRC)的危险因素,建立针对不同年龄段人群的风险预测模型并比较预测效果。方法:选择2012—2022年诊断为结直肠癌患者,记录人口学特征、临床表现、... 详细信息

目的:通过Logis tic回归和支持向量机(SVM)探究早发性结直肠癌(EOCRC)和晚发性结直肠癌(LOCRC)的危险因素,建立针对不同年龄段人群的风险预测模型并比较预测效果。方法:选择2012—2022年诊断为结直肠癌患者,记录人口学特征、临床表现、既往史、家族史、生活方式、体格检查、实验室检查及病理诊断,分别建立风险预测模型,比较两模型的ROC曲线下面积(AUROC)、准确率、精确率、召回率、F1分数。结果:综合两模型结果,EOCRC风险与出现消化道出血、腹胀腹痛、大便习惯改变等临床表现、体重减轻、肿瘤标志物升高具有较强的正相关性,与婚姻状况、阑尾切除史、糖尿病史、血脂异常病史、结直肠癌家族史也存在较弱的正相关;LOCRC风险与婚姻状况、出现临床表现、体重减轻、血脂异常、肿瘤标志物升高具有较强的正相关性,与年龄、吸烟、阑尾切除史、结直肠癌家族史也存在一定的正相关性。两模型的AUROC、准确率、F1分数相差不大,但Logistic回归模型的精确率更高而SVM模型的召回率更高。结论:EOCRC和LOCRC的危险因素不完全相同,婚姻状况、吸烟、血脂异常、肿瘤家族史在EOCRC中的贡献低于在LOCRC中的贡献。相较Logistic回归,SVM能发现更多的结直肠癌危险因素,能尽可能多的找出结直肠癌的可能患者。

关键词：早发性结直肠癌 Logistic回归支持向量机危险因素预测模型

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教研训一体化区域性实践:缘起、路径与策略

教师教育论坛 2024年第3期37卷 46-54页

作者：曾召文许惠芝谢刚易雪冰长沙教育学院长沙410006 长沙市雨花区教育局长沙410007

数字化转型背景下教师教育的创新与变革是当前的热门议题。本研究将研修支持共同体支持下教研训一体化推进作为区域教师发展的一种解决方案。基于成人学习理论,梳理了教师学习的特点;基于系统理论阐述了教学、教研和培训之间的关系,探... 详细信息

数字化转型背景下教师教育的创新与变革是当前的热门议题。本研究将研修支持共同体支持下教研训一体化推进作为区域教师发展的一种解决方案。基于成人学习理论,梳理了教师学习的特点;基于系统理论阐述了教学、教研和培训之间的关系,探讨了教研训一体化的必要性;构建了教研训一体化实施模型,并在研修支持共同体支持下,开展了行动研究。从实践中提炼了几条基本策略,即:基于系统思维与共情意识,构建经验交互的活动序列;基于理念方法和技术引领,搭建学员学习的支架系统;基于团队实践与研训支持,促进反思性实践持续发生;基于环境建设与数据赋能,促进学员经验的不断扩充;基于自我反思与专家引领,促进学员实践智慧的形成。本研究致力于探索教师培养路径方法的创新,旨在为教师专业发展提供可复制、可推广的实践经验。

关键词：研修支持共同体教研训一体化策略研究教师专业发展

2020年11月19-20日哈尔滨市特大暴雪的特征及模式预报结果对比分析

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黑龙江气象 2024年第1期41卷 27-31页

作者：姜兵于凯旋付洪泰景学义杜静高梦竹董学贤哈尔滨市气象局黑龙江哈尔滨150000 黑龙江省气象台黑龙江哈尔滨150000 鸡西市气象局黑龙江鸡西158100

利用常规观测资料、地面自动站资料,对2020年11月19—20日哈尔滨市大范围特大暴雪过程的特征及模式预报结果进行对比分析,结果表明:本次降雪过程受江淮气旋影响,降雪时间长达25个小时,6个主城区平均降雪量高达37.7 mm,降雪量存在两个峰... 详细信息

利用常规观测资料、地面自动站资料,对2020年11月19—20日哈尔滨市大范围特大暴雪过程的特征及模式预报结果进行对比分析,结果表明:本次降雪过程受江淮气旋影响,降雪时间长达25个小时,6个主城区平均降雪量高达37.7 mm,降雪量存在两个峰值区,前一个峰值区最大小时雪强在3.7 mm/h,后一个峰值区最大小时雪强在5.3 mm/h,属特大暴雪量级。本次降雪条件水汽条件充沛,整层大气处于饱和状态,低空的东北偏东气流为暴雪区提供了水汽来源。EC模式温度预报中,临近时间起报的结果较好,模式预报温度平均偏高2-3℃,较强转折性的倒温度天气,EC模式预报效果较差;降雪预报中,较长时间起报的降雪量级较为准确,但开始、结束时段较临近时间起报的预报误差较大;临近的降雪总量预报骤然减少,大大影响预报员对降雪量的判断,所以在专业气象服务中,先前的预报结论和量级不要轻易地降低或减少,可参考较长时间起报的降雪量级、参考临近时间起报的开始、结束时段。

关键词：暴雪水汽江淮气旋模式预报

直驱风机并入交流电网引发的次同步振荡分析与抑制

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黑龙江电力 2024年第2期46卷 146-150页

作者：薛易吴立涵龙腾飞李天意黑龙江科技大学电气与控制工程学院哈尔滨150022

通过对直驱风机并网模型及短路比原理分析,阐述次同步振荡的发生机理。提出在高压母线侧加装静止无功补偿器去抑制次同步振荡的发生,并对静止无功补偿器的控制策略进行分析。结果表明,该控制策略能有效抑制次同步振荡现象,保障电力系统... 详细信息

通过对直驱风机并网模型及短路比原理分析,阐述次同步振荡的发生机理。提出在高压母线侧加装静止无功补偿器去抑制次同步振荡的发生,并对静止无功补偿器的控制策略进行分析。结果表明,该控制策略能有效抑制次同步振荡现象,保障电力系统的安全与稳定。

关键词：直驱风机次同步振荡静止无功补偿器短路比