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基于优化极限学习机模型的反应堆中子通量与k_(eff)预测方法研究
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作者 陈镜宇 刘喜洋 +2 位作者 赵鹏程 刘紫静 李卫 《核技术》 EI CAS CSCD 北大核心 2024年第10期178-187,共10页
通过模拟和扩展人类智能,人工智能能够解决预测反应堆k_(eff)和中子通量等问题。本研究选用国际原子能机构(International Atomic Energy Agency,IAEA)反应堆作为研究对象,以稳态时的堆芯中子通量和k_(eff)为预测量,通过堆芯物理分析程... 通过模拟和扩展人类智能,人工智能能够解决预测反应堆k_(eff)和中子通量等问题。本研究选用国际原子能机构(International Atomic Energy Agency,IAEA)反应堆作为研究对象,以稳态时的堆芯中子通量和k_(eff)为预测量,通过堆芯物理分析程序ADPRES生成数据样本后,利用极限学习机(Extreme Learning Machine,ELM)构建中子通量和k_(eff)的基础神经网络模型,随后通过随机森林(Random Forest,RF)评估特征值重要程度以建立各模型最佳输入特征子集,采用遍历方法确定隐藏层最佳神经元数目,最后使用鲸鱼优化算法(Whale Optimization Algorithm,WOA)对其初始权值与阈值进行优化,进一步提高了模型的精度。研究结果显示:经降维优化处理后,神经网络的预测能力有较大提升,其中k_(eff)的预测精度提高了两个量级,中子通量的预测误差降低了87.24%,并且减少了模型训练时间。本文构建方法对快速评估堆芯物理特性有一定参考意义。 展开更多
关键词 极限学习机 鲸鱼优化算法 中子通量 k_(eff) 参数预测方法 随机森林
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Method of fabricating artificial rock specimens based on extrusion free forming(EFF)3D printing
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作者 Xiaomeng Shi Tingbang Deng +2 位作者 Sen Lin Chunjiang Zou Baoguo Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1455-1466,共12页
Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natura... Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natural rock.Extrusion free forming(EFF)is a 3D printing technique that uses clay as the printing material and cures the specimens through high-temperature sintering.In this study,we attempted to use the EFF technology to fabricate artificial rock specimens.The results show the physico-mechanical properties of the specimens are significantly affected by the sintering temperature,while the nozzle diameter and layer thickness also have a certain impact.The specimens are primarily composed of SiO_(2),with mineral compositions similar to that of natural rocks.The density,uniaxial compressive strength(UCS),elastic modulus,and tensile strength of the printed specimens fall in the range of 1.65–2.54 g/cm3,16.46–50.49 MPa,2.17–13.35 GPa,and 0.82–17.18 MPa,respectively.It is capable of simulating different types of rocks,especially mudstone,sandstone,limestone,and gneiss.However,the simulation of hard rocks with UCS exceeding 50 MPa still requires validation. 展开更多
关键词 Artificial rock 3D printing Extrusion free forming(eff) Similarity analysis Mechanical properties
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一种测量缓发中子有效份额β_(eff)的方法 被引量:3
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作者 朱庆福 史永谦 +5 位作者 罗皇达 张巍 刘宏伟 攸国顺 周琦 陈桂美 《原子能科学技术》 EI CAS CSCD 北大核心 2010年第6期650-653,共4页
本工作通过实验与理论计算相结合,给出了测定缓发中子有效份额βeff的新方法。用实验方法确定反应堆临界状态,并测量次临界状态时以βeff为单位的次临界反应性,应用理论程序计算临界时的中子有效增殖因数keff,确定keff的计算偏差,然后... 本工作通过实验与理论计算相结合,给出了测定缓发中子有效份额βeff的新方法。用实验方法确定反应堆临界状态,并测量次临界状态时以βeff为单位的次临界反应性,应用理论程序计算临界时的中子有效增殖因数keff,确定keff的计算偏差,然后理论计算次临界状态下的keff,并用确定keff的计算偏差对次临界状态下计算的keff进行修正,给出次临界状态的反应性。将实验测量结果与理论计算结果相比较,从而给出βeff。这种方法由于是实验确定的反应堆状态,因此,按实验结果计算的keff与理论描述反应堆状态的计算模型关系不大。分析表明,βeff测量结果的精度高于以往测量方法的精度。 展开更多
关键词 缓发中子有效份额βeff 以βeff为单位的次临界反应性 绝对反应性
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次临界堆芯参数变化对K_(eff)值的影响 被引量:1
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作者 邱小平 黎学川 王建华 《南华大学学报(自然科学版)》 2005年第1期42-46,共5页
作为下一代能源的优先选择者,加速器驱动次临界系统ADS能够有效的利用铀和钍资源,并能够转化具有长期放射性的核废料,提高了核安全.文章主要是对快热耦合ADS次临界堆芯进行了描述,利用蒙特卡罗代码MCNP模拟计算一系列不同堆芯参数下的K... 作为下一代能源的优先选择者,加速器驱动次临界系统ADS能够有效的利用铀和钍资源,并能够转化具有长期放射性的核废料,提高了核安全.文章主要是对快热耦合ADS次临界堆芯进行了描述,利用蒙特卡罗代码MCNP模拟计算一系列不同堆芯参数下的Keff值.MCNP程序中最重要的就是输入文件,输入文件各个参数设置的不同都可能对Keff值计算结果产生极大影响.在解决输入文件问题的过程中,根据实际经验对计算条件进行多组假设,并对不同参数条件下产生的结论进行比较,最终得到Keff值的最佳结果. 展开更多
关键词 ADS MCNP程序 次临界反应堆 Keff 加速器驱动次临界系统 Keff 参数
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中国IPO定价效率研究——基于IPO抑价率和EFF值的比较分析 被引量:13
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作者 陈训波 贺炎林 《经济理论与经济管理》 CSSCI 北大核心 2013年第8期47-59,共13页
IPO定价效率是IPO市场的一个研究热点。本文以沪深A股市场首次公开发行并上市的新股为样本,通过IPO抑价率和EFF值指标比较分析了IPO定价效率的行业特征和定价制度特征。研究表明:EFF均值在行业之间的差异不显著,而IR均值在行业之间差异... IPO定价效率是IPO市场的一个研究热点。本文以沪深A股市场首次公开发行并上市的新股为样本,通过IPO抑价率和EFF值指标比较分析了IPO定价效率的行业特征和定价制度特征。研究表明:EFF均值在行业之间的差异不显著,而IR均值在行业之间差异显著;我国IPO定价效率未随时间推移而不断提高,EFF值和IR值呈现出无趋势的特征。在此基础上,本文认为我国IPO定价效率不高的主要原因不是一级市场低价发行,而是二级市场投资者的追捧和半市场化性质的改革,提高IPO定价效率的根本途径在于回归市场化改革。 展开更多
关键词 IPO抑价率 eff 行业特征 IPO定价效率
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高效率EFF2、EFF1三相异步电动机设计中应注意的几个问题
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作者 刘宇琼 《电机技术》 2003年第3期30-32,共3页
叙述了本企业提高三相异步电动机效率而采用的设计、工艺方法及相应出现的问题,并针对这些问题所做的工作,同时提出了一些建议。
关键词 三相异步电动机 设计 机座 散热片 eff2 effl 硅钢片 定子 转子
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BEAVRS堆芯k_(eff)的敏感性与不确定性分析 被引量:2
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作者 秦凯文 杨波 +3 位作者 刘义保 张洁茹 郝鹏飞 刘豪杰 《核技术》 CAS CSCD 北大核心 2022年第2期69-75,共7页
核数据不确定性分析影响着反应堆安全,在反应堆堆芯物理计算过程中具有重要意义。利用SCALE6.1程序包中KENO模块建立反应堆模拟评估和验证基准BEAVRS(Benchmark for Evaluation and Validation of Reactor Simulations)第一循环热态零... 核数据不确定性分析影响着反应堆安全,在反应堆堆芯物理计算过程中具有重要意义。利用SCALE6.1程序包中KENO模块建立反应堆模拟评估和验证基准BEAVRS(Benchmark for Evaluation and Validation of Reactor Simulations)第一循环热态零功率堆芯物理模型,采用TSUNAMI-3D模块开展k_(eff)的敏感性与不确定性分析,分析了不同燃料富集度、不同温度对k_(eff)敏感性与不确定性的影响。结果表明:核数据不确定性导致BEAVRS模型的k_(eff)总的不确定性为0.5016%;^(235)U的平均裂变中子数敏感性导致k_(eff)的敏感性系数最大(0.92658);对k_(eff)不确定性贡献最大的是238U(n,γ)反应截面,为0.29814%;在燃料富集度降低、温度上升时,238U(n,γ)反应截面不确定性会导致k_(eff)的不确定性增大。因此,在开展反应堆堆芯物理计算过程中,应重点关注238U(n,γ)反应截面信息。 展开更多
关键词 BEAVRS模型 k_(eff) 敏感性 不确定性 238U(n γ)反应截面
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熔盐堆有效缓发中子份额β_(eff)的计算及分析 被引量:1
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作者 胡田亮 曹良志 +1 位作者 吴宏春 庄坤 《核动力工程》 EI CAS CSCD 北大核心 2017年第S1期37-40,共4页
有效缓发中子份额(β_(eff))是研究反应堆动态特性的重要参数。在熔盐堆(MSR)中,采用液体燃料,导致β_(eff)的计算与传统的采用固体燃料反应堆的计算方法不同。本文研究了MSRβ_(eff)的计算方法,并对嬗变熔盐堆(MOSART)的β_(eff)进行... 有效缓发中子份额(β_(eff))是研究反应堆动态特性的重要参数。在熔盐堆(MSR)中,采用液体燃料,导致β_(eff)的计算与传统的采用固体燃料反应堆的计算方法不同。本文研究了MSRβ_(eff)的计算方法,并对嬗变熔盐堆(MOSART)的β_(eff)进行了计算,并分析了熔盐在堆外流动时间和熔盐入口速度对β_(eff)的影响。计算结果表明:固定堆芯入口速度,熔盐在堆芯外流动的时间增加,β_(eff)会减小;固定熔盐在堆芯外流动时间,熔盐在堆芯入口速度增大,β_(eff)会减小。 展开更多
关键词 有效缓发中子份额(βeff) 熔盐堆(MSR) 缓发中子先驱核
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Therapeutic effect and mechanism of breviscapine on cisplatin-induced nephrotoxicity in mice 被引量:6
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作者 Xiao-Yu Lou Jing-Liang Cheng Bo Zhang 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2015年第10期853-857,共5页
Objective:To observe the protective effect of breviscapineon mice with cisplatin-induced nephrotoxicity.Methods:Mice were given a single injection of cisplalin(8 mg/kg,up.);then,breviscapine was given to mice at 25 mg... Objective:To observe the protective effect of breviscapineon mice with cisplatin-induced nephrotoxicity.Methods:Mice were given a single injection of cisplalin(8 mg/kg,up.);then,breviscapine was given to mice at 25 mg/kg and 50 mg/kg doses,respectively,once a day for seven days.Renal tissue structure was observed after animals were sacrificed.Blood urea nitrogen(BUN),serum creatinine(Scr),lipid peroxide(MDA) and superoxide dismutase(SOD) serum levels were detected;and MDA,glutathione peroxidase,and SOD levels in the renal cortex were detected.Results:Compared with the blank control group(BCG),the kidney pathological damage of mice in the model control group(MCG) was more severe.After applying different doses of breviscapine,different degrees of renal injury improvement appeared.Compared with the BCG,the serum levels of Scr and BUN in the MCG increased to(89.92±6.78) μmoL/L and(15.32±4.53) mmoL/L.The differences were statistical significant(P<0.01).Compared with the MCG,the serum levels of Scr and BUN in the Bre low-dose groups and Bre high-dose groups decreased significantly(P<0.05).Compared with the BCG,the MDA levels in serum and in the renal cortex in the MCG significantly increased,while the SOD levels significantly decreased.Both the differences were statistically significant(P<0.01).In the Bre low-dose groups and Bre high-dose groups,MDA levels in serum and in the renal cortex significantly decreased,while SOD and glutathione peroxidase levels in the renal cortex significantly increased,compared with the MCG;and the differences were statistically significant(P<0.05).Conclusions:Breviscapine can reduce cisplatin induced renal toxicity in mice and it's possible through inhibition of renal tubule cell lipid peroxidation and reduces the nephrotoxicity of cisplatin. 展开更多
关键词 CISPLATIN RENAL INJURY BREVISCAPINE Protective eff
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启明星实验装置设计方案中K_(eff)与最优化参数的计算 被引量:2
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作者 王晓宇 冯开明 +1 位作者 黄锦华 张国书 《核聚变与等离子体物理》 CAS CSCD 北大核心 2004年第2期123-128,共6页
在验证加速器驱动系统的启明星实验装置的设计方案中,利用蒙特卡罗程序(MCNP)对有效增殖系数Keff进行了计算,并对与Keff密切相关的热区燃料元件栅距和热区厚度进行了最优参数的计算。结果表明,启明星实验装置的Keff能够达到设计的目标。
关键词 启明星实验装置 MCNP程序 蒙特卡罗程序 反应堆
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The plurality effect of topographical irregularities on site seismic response 被引量:7
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作者 Saeed Ghaffarpour Jahromi Sama Karkhaneh 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第3期521-534,共14页
Topography can have signifi cant eff ects on seismic ground response during an earthquake because topographic irregularities cause considerable diff erences between the seismic waves emitted by the source and the wave... Topography can have signifi cant eff ects on seismic ground response during an earthquake because topographic irregularities cause considerable diff erences between the seismic waves emitted by the source and the waves reaching the ground surface. When a seismic motion happens in a topographically irregular area, seismic waves are trapped and refl ected between the topographic features. Therefore, the interaction between topographies can amplify seismic ground response. In order to reveal how interaction between topographies infl uences seismic response, several numerical fi nite element studies have been performed by using the ABAQUS program. The results show that topographic features a greater distance between the seismic source and the site would cause greater seismic motion amplifi cation and is perceptible for the hills far away from the source and the ridges. Also, site acceleration response is impacted by surrounding topography further than site velocity and displacement response. 展开更多
关键词 TOPOGRAPHY eff ECTS surrounding TOPOGRAPHY site seismic response ABAQUS PROGRAM and PLAXIS PROGRAM
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Effect of site amplification on inelastic seismic response 被引量:4
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作者 Adhikary S Singh Y 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第3期535-554,共20页
The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility ... The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility demand, on the eff ective periods, is investigated, and inelastic site amplifi cation is shown to be strongly correlated to the normalized eff ective period. Two non-dimensional parameters, analogous to the conventional site amplifi cation factors in codes, are defi ned to quantify the inelastic site amplifi cation. It is shown that the inelastic site amplifi cation factor (i.e. ratio of constant ductility spectral ordinates at soil site to those at rock outcrop) is able to represent the site eff ects more clearly, as compared to the inelastic site amplifi cation ratio (i.e. ratio of inelastic spectral ordinates at soil site to the corresponding elastic spectral ordinates at rock outcrop). Further, the peak in the amplifi cation factor corresponding to the eff ective site period diminishes rapidly with increasing ductility demand. 展开更多
关键词 SITE amplifi CATION normalized RESPONSE SPECTRA eff ective period INELASTIC SEISMIC RESPONSE INELASTIC SITE amplifi CATION factor
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基于m_(eff)指数的多尺度景观破碎化空间特征研究——以宁国市为例
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作者 谷晓阳 喻根 王晓辉 《安徽农业科学》 CAS 2017年第13期46-51,共6页
采用CBC算法计算的m_(eff)指数,基于GIS技术,以宁国市、乡镇、1 km^2格网3种不同空间尺度区域为报告单元,选取城市建设区域、道路、农田、采矿区、采伐区、水体6类景观破碎因子组成景观破碎几何量度,研究宁国市景观破碎空间分布特征。... 采用CBC算法计算的m_(eff)指数,基于GIS技术,以宁国市、乡镇、1 km^2格网3种不同空间尺度区域为报告单元,选取城市建设区域、道路、农田、采矿区、采伐区、水体6类景观破碎因子组成景观破碎几何量度,研究宁国市景观破碎空间分布特征。结果表明,基于3种报告单元的m_(eff)值为0~422.92 km^2;宁国市景观破碎空间分布特征明显,破碎程度较重区域空间上呈"人"字形分布,城区破碎化水平最高,市域西北部、南部部分地区破碎程度相对较轻。 展开更多
关键词 景观破碎 空间分布特征 M eff指数 多尺度报告单元 景观联通性 宁国市
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Bauschinger-Like Effect of AZ31 Magnesium Alloy Wide Sheet During the Straightening Process 被引量:2
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作者 Fangkun Ning Qichi Le +1 位作者 Yonghui Jia Liang Chen 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2021年第9期1255-1264,共10页
The Bauschinger-like effect, which showed up in the straightening process of the AZ31 magnesium alloy wide sheet, was investigated through the multi-pass discrete three-point bending–unloading–bending(BUB) experimen... The Bauschinger-like effect, which showed up in the straightening process of the AZ31 magnesium alloy wide sheet, was investigated through the multi-pass discrete three-point bending–unloading–bending(BUB) experiments. The stress variable, anisotropy, and asymmetry of tension and compression on the straightening process were corresponding to the Bauschingerlike effect. The Bauschinger-like effect in the initial, intermediate, and end of the straightening process was dominated by the twinning, detwinning, and dislocation induced by pyramidal < c + a > slip, respectively. Also, they were responsible for the transformation of the Bauschinger stress parameter(BSP) and Bauschinger energy parameter(BEP). Later, the anisotropic nonlinear kinematic hardening model(ANK model) to describe the Bauschinger-like effect was optimized and simplified. 展开更多
关键词 Bauschinger-like eff ect STRAIGHTENING Discrete experiments Anisotropic nonlinear kinematic hardening model(ANK model)
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The conversion factor of K_(eff) to K_(3.7) in thermoluminescence dating 被引量:3
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作者 Wang Wei-Da Zhou Zhi-Xin +1 位作者 Xia Jun-Ding (Research Laborotory for Conservation and Archaeology, Shanghai Museum, Shanghai 200951)Leung P L Stokes M J(Department of Physics and Materials Science, City University of Hong Kong) 《Nuclear Science and Techniques》 SCIE CAS CSCD 1998年第4期227-230,共4页
In the fine-grain TL dating the full o dose must be converted into the equivalent P dose. The conversion is finished by Keff-value, which is an effective or effectiveness. But the Keff can not be measured directly for... In the fine-grain TL dating the full o dose must be converted into the equivalent P dose. The conversion is finished by Keff-value, which is an effective or effectiveness. But the Keff can not be measured directly for each sample and only the external radiative efficiency K3.7 can be measured. In order to obtain the Keff a special study for the conversion factor of Keff to K3.t has been made using the ultrathin TLD. The results show that the conversion factor of tile TLD for archaeological samples is 0.847, which is in agreement with calculated value 0.85. 展开更多
关键词 考古学 热致发光断定年代 Keff-K3.7 变换因子
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Single and combined eff ects of fertilization,ectomycorrhizal inoculation,and drought on container-grown Japanese larch seedlings 被引量:1
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作者 Evgenios Agathokleous Mitsutoshi Kitao +3 位作者 Masabumi Komatsu Yutaka Tamai Hisanori Harayama Takayoshi Koike 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第4期1077-1094,共18页
Climate change can intensify drought in many regions of the world and lead to more frequent drought events or altered cycles of soil water status.Therefore,it is important to enhance the tolerance to drought and thus ... Climate change can intensify drought in many regions of the world and lead to more frequent drought events or altered cycles of soil water status.Therefore,it is important to enhance the tolerance to drought and thus health,vigor,and success of transplantation seedlings used in the forestry by modifying fertilization and promoting mycorrhization.Here,we sowed seeds of Japanese larch(Larix kaempferi)in 0.2-L containers with 0.5 g(low fertilization;LF)or 2 g(high fertilization;HF)of slow-release fertilizer early in the growing season.One month later,we irrigated seedlings with non-sterilized ectomycorrhizal inoculum(ECM)or sterilized solution(non-ECM),and after about 2 months,plants were either kept well watered(WW;500 mL water/plant/week)or subjected to drought(DR;50 mL water per plant/week)until the end of the growing season.HF largely stimulated plant growth and above-and belowground biomass production,eff ects that are of practical signifi cance,but caused a small decrease in stomatal conductance(Gs 390)and transpiration rate(E 390),which in practice is insignifi cant.ECM treatment resulted in moderate inhibition of seedling growth and biomass and largely canceled out the enhancement of biomass and foliar K content by HF.DR caused a large decrease in CO 2 assimilation,and enhanced stomatal closure and induced senescence.DR also largely depleted foliar Mg and enriched foliar K.Although DR caused a large decrease in foliar P content in LF,it moderately increased P in HF.Likewise,DR increased foliar K in HF but not in LF,and decreased foliar P in ECM plants but not in non-ECM plants.Conversely,ECM plants exhibited a large enrichment in foliar P under WW and had a lower water potential under DR when grown in LF.These results indicate that the drought tolerance and health and vigor of Japanese larch seedlings can be modifi ed by soil fertility and soil microorganisms.This study provides a basis for new multifactorial research programs aimed at producing seedlings of superior quality for forestation under climate change. 展开更多
关键词 DROUGHT ECTOMYCORRHIZAE Fertilizer eff ect Oxidative stress Stressor interactions
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Effect size in papers published by the Journal of Forestry Research:A missing treasure? 被引量:1
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作者 Evgenios Agathokleous Lei Yu 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第2期297-299,共3页
P values based on standard hypothesis testing are commonly reported in articles published by the Journal of Forestry Research(JFR).However,effect sizes are barely used and reported,even if they are of direct relevance... P values based on standard hypothesis testing are commonly reported in articles published by the Journal of Forestry Research(JFR).However,effect sizes are barely used and reported,even if they are of direct relevance to the primary questions of many of the published studies.The incorporation of effect sizes in studies published by JFR should be encouraged and promoted.Inclusion of effect sizes as a requirement in the journal guidelines will facilitate a major change in the way data are tested and interpreted,with the ultimate goal to exempt researchers from the custom of drawing conclusions merely based upon a dichotomous statistical result(P value).Such a policy can also lead to more informed decisions of whether identified effects are of practical relevance to the forestry. 展开更多
关键词 eff ect magnitude Null hypothesis signifi cance testing P value Science communication Scientifi c writing
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Metal Oxide/Nitrogen-Doped Carbon Catalysts Enables Highly Effi cient CO_(2) Electroreduction 被引量:1
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作者 Han Shi Yingying Cheng Peng Kang 《Transactions of Tianjin University》 EI CAS 2021年第3期269-277,共9页
The metal oxide/nitrogen-doped carbon(NC)compounds zirconium oxide/NC(ZrO_(2)/NC)and cerium oxide/NC(CeO_(2)/NC)were synthesized via the pyrolysis of polyaniline on the metal oxide surface.The characterization of the ... The metal oxide/nitrogen-doped carbon(NC)compounds zirconium oxide/NC(ZrO_(2)/NC)and cerium oxide/NC(CeO_(2)/NC)were synthesized via the pyrolysis of polyaniline on the metal oxide surface.The characterization of the ZrO_(2)/NC and CeO_(2)/NC catalysts showed more active CO_(2) reduction reaction activity than that of NC catalyst without metal oxide.Gas chromatography analysis revealed that CO and H_(2)were the primary products,and no liquid-phase products were detected via proton nuclear magnetic resonance spectroscopy or high-performance liquid chromatography.The maximum Faraday effi ciency of ZrO_(2)/NC reached 90%at−0.73 V(vs.RHE),with the current density of CO at 5.5 mA/cm^(2);this Faraday effi ciency value was higher than that of NC(41%),with the current density of CO at 3.1 mA/cm^(2).The interaction between the metal oxide and carbon allowed the effi cient formation of defect sites,especially imine-type nitrogen,strengthening the adsorption of the key reaction intermediate CO_(2)^(•−) and thus promoting the CO_(2) reduction reaction. 展开更多
关键词 Metal oxide Nitrogen-doped carbon Interface eff ect CO_(2)reduction reaction
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Cost-Effective Machining of Granite by Reducing Tribological Interactions 被引量:1
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作者 LI Yuan 1, HUANG Hui 1, SHEN Jian-yun 1, XU Xi-peng 1, GAO Yong-sheng 2 (1. Province Key Lab of Stone Machining, Huaqiao University, Quanzhou 362011, China 2. Department of Mechanical Engineering, Hong Kong University of Science and T echnology, Hong Kong, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期123-,共1页
In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the wor... In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the workpiece surfaces are maintained to be satisfactory. It is understood that the main factors affecting the tool wear, the energy, and the efficiency during the machining process are related to the tribological interactions that occur at the interface between the diamond tool surface and the workpiece. Based on this consideration, we propose a new machining method to machine granite materia ls to achieve improved cost effectiveness. In the proposed method, the tribologi cal interactions are maintained to a minimum. Based on the analyses of the experimental results, the following conclusions can be drawn: The wear performance is greatly dependent on the machining parameters and their combination. Therefore, optimum machining parameters must be set up at first in order to optimize the tribological characteristics of segments and thereby sawbl ade performance. These may be realized by balancing the energy expended by frict ion and the mechanical load on diamond crystal. The geometry and structure of diamond segments are another important criterion f or the diamond saw blade. Using a seven-layer structure for multi-blades sawin g and applying segments with side slots for trimming application had greatly red uced the frictions in the sawing processes. The wetting and bonding between diamonds and matrix alloys have been considered as the prerequisite for high wear performance of the segments. Diamonds coated w ith Ti-Cr alloy by a unique technique can effectively improve its wetting c apability and provide more storage space for debris, thereby reducing friction i nteractions. 展开更多
关键词 GRANITE SAWING friction interaction cost-effe ctive
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AP1000堆芯物理计算中核数据对k_(eff)的敏感性与不确定性分析
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作者 秦凯文 杨波 +2 位作者 刘义保 张洁茹 郝鹏飞 《能源研究与管理》 2022年第2期61-67,共7页
核数据作为反应堆计算的输入参数,其不确定性对堆芯物理计算至关重要。以第3代先进压水堆AP1000首循环零功率堆芯为研究对象,采用SCALE6.1程序建立堆芯物理模型,分别计算了反应堆冷态和热态工况下,5种典型硼浓度的堆芯有效增殖因子k_(ef... 核数据作为反应堆计算的输入参数,其不确定性对堆芯物理计算至关重要。以第3代先进压水堆AP1000首循环零功率堆芯为研究对象,采用SCALE6.1程序建立堆芯物理模型,分别计算了反应堆冷态和热态工况下,5种典型硼浓度的堆芯有效增殖因子k_(eff),并与AP1000设计文件基准值进行比对,误差在50 pcm以内,验证了模型准确性。随后开展核数据对k_(eff)的敏感性和不确定性分析,结果表明,低能区中^(235)U的平均裂变中子产额、^(10)B的(n,α)反应截面、共振区中^(1)H的弹性散射截面、快中子区中^(238)U的裂变截面具有较大的敏感性与不确定性,在反应堆物理计算工程中应重点关注。 展开更多
关键词 核数据 有效增值因子k_(eff) 敏感性 不确定性 AP1000
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